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Spin-lattice (T1) and spin-spin (T2) relaxation times of proton, deuteron, and oxygen-17 in muscle water have been measured at 9.21 MHz in the temperature range of 0 degree--40 degrees C. The values of the apparent activation energy for the three nuclei are (in kJ . mol-1) 9.1, 19, and 18 for 1/T1, and -1.3, 4.2, and 14 for 1/T2, respectively. The relatively small values for T2 for 1H and 2H and their low apparent activation energies are attributed to hydrogen exchange between water and proteins; this exchange does not affect the 17O relaxation. Quantitative calculations on deuteron T1 and oxygen-17 T1 and T2 have been made. The effect of surface-induced anisotropy on a minor fraction of water molecules is considered in some detail, and a new expression for its spectral density similar to that of liquid crystalline systems is applied in the calculation. It is suggested that water on the surfaces of macromolecules has a rotational correlation time of tau c approximately 1 x 10(-9) S, with a time constant of tau x approximately 3 x 10(-7) S, which is characteristic of the relaxation of the local structure. | US |
Currently used methods for plasma cAMP measurements are either tedious (chromatographic preparation of sample) or potentially inaccurate (direct assay of plasma samples). A rapid, simple, and accurate competitive binding assay for plasma cAMP, which does not require chromatographic preparation of the sample, has been developed. This procedure prevents destruction of plasma cAMP by utilizing both theophylline and EDTA in the collection of the blood sample. Human plasma contains variable amounts of cAMP-binding activity which interfere with the measurement of cAMP by the standard competitive binding assay. Our assay procedure removes this binding activity by precipitation of plasma proteins with perchloric acid. The normal fasting value (+/- SD) of plasma cAMP using this technique is 17.6 +/- 4.3 pmol/ml, which is identical to values obtained by methods utilizing chromatographic purification of samples (18.3 +/- 3.0). The fasting plasma cAMP of patients with hyperparathyroidism is normal (16.2 +/- 3.4), but patients with maturity-onset diabetes mellitus have fasting values significantly below normal (12.3 +/- 2.4). | US |
The immunoreactive (RIA), ACTH, LPH, alpha endorphin (alpha End) and beta End in an extract of a human pancreatic islet cell carcinoma causing the ectopic ACTH syndrome were assayed after gel exclusion chromatography. In addition to "big", "intermediate" and "little" ACTHs, beta lipotropin (beta LPH) and gamma LPH, the eluate fractions contained RIA-alpha End and -beta End. The major RIA-beta End component appeared to be h beta LPH, which has beta End as its carboxy-terminus, but significant concentrations of a component that coeluted with synthetic p beta End were also found. Small amounts of RIA-alpha End were found in two peaks, one that may have represented 1-76 h beta LPH, with alpha End as its carboxy-terminus, and one probably representing alpha End itself. RIA-ACTH, -LPH and -beta End were found in the void volume fractions. Thus, a human nonpituitary tumor that produced ACTH and LPHs also produced endorphins, all perhaps deriving from a common precursor. | US |
This report describes, at least in part, the role of prostaglandin and cyclic nucleotide metabolism in the etiology of the vascular disease associated with diabetes mellitus. Alterations in this metabolism seem associated with induction of platelet aggregation leads to microthromboses leads to microangiopathy sequences that are subtle but inexorable over a long period of time. Prostaglandins are generally elevated in blood from patients having frank signs of diabetic retinopathy when compared with nondiabetic subjects. Prostaglandin concentration remained elevated in diabetic retinopathy patients receiving indomethacin. We formed, therefore, the working hypothesis--yet to be fully tested either in patients or animal models with and without indomethacin treatment--that the increased prostacyclin (synthesized by endothelial microsomes) and cyclic-AMP production, both of which favor prevention of platelet aggregation, accompany the increased concentration of one or more of the prostaglandin E and F compounds. Concurrently, there may be an accompanying reduction of thromboxane A2 (synthesized by platelet microsomes) and cyclic-GMP (both of which favor platelet aggregation) production in the diabetic patients. The elevated prostaglandin in the diabetic patients not receiving indomethacin could possibly be directed toward slowing but not preventing the progression of the complex disease process in diabetes. | US |
Characteristic EEG sleep changes in depression are highlighted by a sleep continuity disturbance, delta sleep reduction, and a shortened REM latency. Since these findings have been derived primarily from only a few baseline recordings, questions regarding their persistence and/or variability have not been previously addressed. As part of an extensive set of investigations of EEG sleep in depression, we examined nightly the sleep of 12 hospitalized, non-delusional, primary depressives who were involved in a program of active psychosocial treatment intervention and received only placebo during a 5-week study period. EEG sleep findings revealed a relative lack of change across time, particularly in those parameters reported to be associated with a primary or 'biologic' depressive episode. While some degree of clinical improvement was noted, the group failed to achieve a state of remission or even partial remission as determined by the Hamilton Rating Scale. It appears that the major sleep alterations associated with such disorders persist for up to at least 5 weeks in the absence of pharmacologic or other somatic intervention. | US |
The effect or oral glucose ingestion on renal phosphate reabsorption was studied in 13 patients with the inherited form of vitamin D-resistant rickets (VDRR) and 5 normal subjects. In contrast to the normal subjects, glycosuria developed in six VDRR patients after glucose ingestion and resulted in a further 43% decrease in renal phosphate reabsorption. This was accompanied by a 33% increase in phosphate clearance. This was not attended by differences in fasting glucose or phosphorus levels between groups, or in their respective values 1 h after glucose ingestion. Baseline renal phosphate reabsorption was less and baseline phosphate clearance was greater in those VDRR subjects who developed glycosuria. The accumulated data suggest that excessive glucose ingestion by some patients with VDRR may add an additional insult to the phosphaturia characteristic of this disorder. This, in turn, would further compromise the response of circulating phosphate to therapeutic attempts at oral phosphate supplementation, thereby reducing the efficacy of oral phosphate therapy on skeletal growth and development in this disorder. | US |
A patient with hypoadrenocorticism was found to have low basal plasma concentrations of ACTH and lipotropins and deficient responses of these hormones to insulin-induced hypoglycemia and lysine vasopressin. The adequacy of secretion of other anterior pituitary hormones was assessed either directly, by measuring their concentration in plasma, or indirectly, by assessing end organ function, under basal and stimulated conditions. The responses of gonadotropins to LRH and of PRL and TSH to TRH were normal. The etiology of this rare condition of isolated deficiency of ACTH and lipotropins remains to be elucidated. | US |
A 64-yr-old female presented with severe osteoporosis and easy bruisability of over 2-yr duration. Biopsy of a neck mass revealed medullary carcinoma of the thyroid. Subsequently, lymphangitic pulmonary metastases were demonstrated which had been present radiographically for at least 4 yr. Basal serum calcitonin was markedly elevated and increased during calcium infusion. The diagnosis of ectopic ACTH syndrome was first entertained when hypokalemic alkalosis was observed during evaluation of her carcinoma. Elevated urinary 17-hydroxycorticosteroids, 17-ketosteroids, plasma cortisol, and immunoreactive plasma ACTH levels were documented. Adrenal steroidogenesis seemed to suppress on high dose dexamethasone. The primary tumor and its metastases contained high concentrations of immunoreactive ACTH and beta-melanocyte-stimulating hormone. Hepatic metastases contained extremely high concentrations of calcitonin. In contrast to the usual presentation of the ectopic ACTH syndrome as primarily hypokalemic alkalosis and glucose intolerance, patients with relatively benign and indolent ACTH-secreting tumors, such as certain cases of medullary carcinoma of the thyroid, may present with more typical signs and symptoms of Cushing's syndrome. The more pronounced cushingoid features in this latter group presumably reflects a more prolonged period of exposure to elevated glucocorticoid levels. Ten cases of ACTH-secreting medullary carcinoma of the thyroid from the literature are discussed. Extopic ACTH production by such tumors should be considered in the evaluation of patients with Cushing's syndrome or unexplained severe osteopenia. | US |
Normal adrenal and adrenal tumor cells from a female infant with a virilizing adrenal tumor were grown in tissue culture as monolayers for a period of 7 weeks. Half of the cultures were exposed to ACTH (0.1 U/ml). The cells grew well and continued to produce steroid hormones over the entire period in culture. Production of steroid hormones was measured by RIA of individual steroids in the culture medium. Unstimulated normal and tumor cells produced equivalent amounts of cortisol, 11 beta, 18, 21-trihydroxy-4-pregnene-3,20-dione, and 18,21-dihydroxy-4-pregnene-3,20-dione, but tumor cells produced lesser amounts of dehydroepiandrosterone (DHA), androstenedione, testosterone, and progesterone. Normal cells exposed to ACTH showed an increase in all steroids measured, whereas ACTH-exposed tumor cells showed an increase principally in DHA consistent with a deficiency in 3 beta-hydroxysteroid dehydrogenase activity. Circulating levels of DHA, androstenedione, and testosterone were elevated in the patient before removal of the adrenal tumor. The production of androgens by tumor cells in vitro resembled the pattern of circulating steroids in vivo. These studies demonstrate that tissue culture of human adrenal cells provides a means both to determine their biochemical characteristics and to investigate their responses to exogenous hormones. | US |
A study was performed to determine the possible role of angiotensin II (AII) in mediating the increased adrenal aldosterone response to infused alpha 1-24-ACTH, induced by sodium deprivation. Nine normal subjects, aged 18-31 yr. received 8-h infusions of 1) alpha 1-24-ACTH (0.5 U given over 8 h) while on a diet with unrestricted sodium content; 2) saralasin at 0.5 micrograms/kg/min or ACTH alone (0.5 U over 8 h) on the 7th day of a 10 meq sodium diet; and 3) ACTH and saralasin together on the 8th day while still on sodium restriction. AII was administered for the last 2 h of infusion 3. Plasma cortisol and aldosterone concentrations were measured at hourly intervals during the infusions and plasma renin activity was measured at 2 hourly intervals. ACTH infusion produced an increase in the plasma aldosterone concentration which was significantly greater during sodium restriction than when sodium intake was unlimited. This increase was not associated with an ACTH-induced rise in the plasma renin activity and was not significantly altered when ACTH was administered with saralasin. The rise in plasma cortisol concentration induced by ACTH was not significantly different when the normal subjects were on liberal and restricted sodium intakes. It is concluded that AII plays little if any acute role in increasing the stimulatory action of ACTH on aldosterone secretion during sodium restriction. | US |
A 15.5-yr-old black male is reported with hypocalcemia, hyperphosphatemia, and severe osteitis fibrosa cystica. While hypocalcemic and hyperphosphatemic, the circulating parathyroid hormone (PTH) level and urinary cAMP excretion were increased. An infusion of exogenous PTH produced a normal maximal excretion of urinary cAMP but failed to increase phosphate excretion. Correction of the hypocalcemia by administration of 200,000 U vitamin D daily lowered the endogenous PTH level and basal excretion of cAMP to normal; at that time, infusion of PTH produced both a normal rise in urinary cAMP and a normal phosphaturic response. This pattern of response suggests pseudohypoparathyroidism with a calcium-sensitive defect in renal phosphate transport distal to the PTH receptor adenyl cyclase mechanism, producing hyperphosphatemia, hypocalcemia, and secondary hyperparathyroidism. The osteitis fibrosa cystica was presumably due to the increased PTH, suggesting that resistance to PTH was present in kidney but not bone. | US |
Twenty-one unselected patients with recurrent nephrolithiasis and normocalcemic hypercalciuria with or without hypophosphatemia and 18 normal subjects were studied with an oral calcium tolerance test and for 3- to 5-day periods while consuming a low normal (400 mg) and high-normal (1000 mg) calcium intake. The oral calcium tolerance test consisted of the measurement of the calcemic, calciuric, and parathyroid (assessed by determinations of serum immunoreactive parathyroid hormone and nephrogenous cAMP) responses to acute 1000- or 350-mg doses of calcium. Nineteen patients displayed normal results for basal serum calcium, parathyroid function, and fasting calcium excretion, and striking calcemic (mean increase in serum calcium, 0.9 vs. 0.2 mg/dl in the normal subjects) and calciuric (mean increase in urinary calcium, 0.33 vs. 0.15 mg calcium/100 ml GF in the normal subjects) responses to the 1000-mg calcium tolerance test, associated with a mean 54% suppression in nephrogenous cAMP. These patients were operationally defined as having "absorptive" hypercalciuria. The variable occurrence of hypophosphatemia in this group suggested that the pathogenesis of "absorptive" hypercalciuria may be complex and/or multifactorial. There were strong positive correlations between the calciuric response to the calcium tolerance test and fractional isotopic calcium absorption (r = 0.75, P less than 0.00), the calcemic responses to the test (r = 0.71, P less than 0.001) and the calciuric responses noted on the 1000- vs. the 400-mg daily calcium intake (r = 0.78, P less than 0.001). Two patients displayed low or low normal basal serum calcium, increased parathyroid function, increased fasting calcium excretion, and a striking calciuric but minimal calcemic response to the 1000-mg calcium tolerance test, associated with a moderate suppression in nephrogenous cAMP. These patients were operationally defined as having "renal" hypercalciuria. Several lines of evidence indicated that the hyperparathyroidism in these patients was physiological or secondary, including the near normalization of parathyroid function on the daily 1000-mg calcium intake. A steep slope of calcium excretion on calcium intake (due to increased calcium absorption) was noted in all hypercalciuric patients and accounted for the significantly improved diagnostic accuracy of screening patients for hypercalciuria on the high-normal calcium intake. The simple measurement of total cAMP excretion (nanomoles per 100 ml GF) and urinary calcium on the 1000-mg daily calcium intake seemed to provide reliable separation of patients with "renal" from those with "absorptive" hypercalciuria. A physiological (350 mg) dose of oral calcium produced a 30% suppression of nephrogenous cAMP in normal subjects; this suggests that dietary calcium exerts an important control of parathyroid function under physiological circumstances. | US |
Bilateral paratesticular tumors were observed in a 32-yr-old man 14 yr after he developed a pituitary tumor after adrenalectomy for Cushing's disease (Nelson's syndrome). Plasma ACTH concentrations were markedly elevated (mean, 6350 pg/ml), but urinary free cortisol concentrations were low (27-31 micrograms/24 h). Catheterization revealed a spermatic to peripheral venous gradient for cortisol consistent with secretion of this steroid by the tumor. This was confirmed by decreased cortisol excretion after tumor excision. Serum androgen (testosterone, androstenedione, dihydrotestosterone, and dehydroepiandrosterone-sulfate) and progestin (progesterone and 17-hydroxyprogesterone) concentrations were decreased and did not decline further after tumor removal. These latter observations suggested that the paratesticular tumors did not secrete appreciable testosterone or any of its immediate precursors. Serum gonadotropin levels were also low. Cyproheptadine treatment resulted in a marked lowering of plasma ACTH concentrations (221-320 pg/ml). This was associated with an increase in both plasma LH and testosterone concentrations. These observations are consistent with the hypothesis that ACTH may directly affect LH and testosterone secretion. | US |
One hundred fourteen hypertensives and 20 normal controls were examined using a new clinical technique of measuring 24-h urinary free 18-hydroxy-11-desoxycorticosterone (18-OH-DOC) excretion in response to dietary salt manipulations and ACTH injections. The object was to avoid potential errors of random plasma sampling. Mean urinary free 18-OH-DOC in normals on 110 milliequivalent sodium diet was 1.84 +/- 0.69 microgram (mean +/- SD) and represented about 2% of the daily secretion rate of this steroid. Both in normals and hypertensives, urinary free 18-OH-DOC approximately doubled on low salt (P less than 0.01 for each) and rose about 10 times in response to ACTH injection (P less than 0.05 and P less than 0.01, respectively). Plasma and urinary free 18-OH-DOC showed good correlation in patients with essential hypertension on a low salt diet (r = 0.45, P less than 0.01). Suppressed renin patients showed no propensity toward excess 18-OH-DOC excretion and hypertensives with elevated 18-OH-DOC could not be distinguished by their aldosterone levels, cortisol levels, nor their responses to various stimuli. These data suggest 18-OH-DOC is predominantly secreted under ACTH control and, to a smaller extent, in response to salt changes. Hypertension characterized by chronic overproduction of 18-OH-DOC forms only a small percentage of the hypertensive population. It is proposed that measuring 24-h urinary free 18-OH-DOC excretion may be the best method of assessing its rate of secretion without resorting to injection of radiolabeled material. | US |
To study dynamic interactions among parathyroid hormone (PTH), plasma calcium, and brain states, seven normal subjects were studied for a total of eight nights in our sleep laboratories. Plasma samples were obtained at 10- to 20-min intervals for PTH and calcium determinations. Electroencephalogram, eye movements, and muscle tone were recorded to determine sleep stages. On each night, several distinct peaks in PTH concentration were seen, which in some cases exceeded the all night mean PTH by as much as 300%. Peaks in plasma PTH were significantly nonrandom and tended to recur about every 100 min. PTH concentration was significantly related to cycles of stages 3 and 4 sleep. Total plasma calcium varied less but was significantly related to cycles of rapid eye movement sleep and to cycles of stage 2 sleep. PTH and calcium were significantly interrelated, especially at high frequencies above 40 cycles/day (1 cycle 36 min). In the 14.4 cycles/day (1 cycle/100 min) frequency range where most PTH and calcium variability was found, however, PTH and calcium were more closely related to sleep stages than to each other. These results suggest that the regulation of PTH and calcium is complex and may involve interactions with neural systems. | US |
Seven patients with Cushing's syndrome were treated with trilostane (WIN 24,540) 4 alpha,5-epoxy-17 beta-hydroxy-3-oxo-5 alpha-androstane-2 alpha-carbonitrile), an inhibitor of adrenal steroid biosynthesis. Trilostane treatment reduced steroid biosynthesis and it also improved biochemical manifestations of the disease in all of the patients treated. The average cortisol secretory rate decreased significantly with treatment, from 47.1 to 23.4 mg/24 h (P less than 0.005), and urinary 17-hydroxycorticosteroids decreased from 15.7 to 8.7 mg/24 h (P less than 0.01). Urinary free cortisol excretion decreased from 277 to 88 microgram/24 h (P less than 0.01), and 0800 h plasma cortisol levels declined from 25.0 to 12.0 microgram/dl (P less than 0.05). Conversely, dehydroepiandrosterone sulfate excretion in urine increased from 1.3 to 5.8 mg/24 h (P less than 0.0025) and in plasma increased from 162 mg/24 h (P less than 0.025). Plasma and urinary free dehydroepiandrosterone increased 2-fold. Urinary 17-ketosteroid excretion increased from 18 to 43 mg/24 h (P less than 0.001). A significant reduction in urinary excretion of tetrahydroaldosterone, tetrahydrodeoxycorticosterone, and 18-hydroxytetrahydrodeoxycorticosterone was observed with treatment. Inhibition of steroid biosynthesis was accompanied by a 2-fold increase in PRA and no change in serum cholesterol levels. Mean arterial blood pressure decreased with treatment from 109 to 97 mm Hg (P less than 0.005), and fasting blood sugar decreased from 117 to 98 mg/dl (P less than 0.005), accompanied by rise in plasma potassium levels from 3.8 to 4.3 milliequivalents/liter (P less than 0.025). Two patients on long term therapy also showed an improvement in clinical features of their disease. There were no significant treatment-related carcinoma, simultaneously producing both an excessive amount of cortisol and ACTH, is described. It is concluded that trilostane is an effective inhibitor of 3 beta-hydroxysteroid dehydrogenase enzyme system in human adrenal gland; it inhibits biosynthesis of cortisol and it is useful in the treatment of Cushing's syndrome. | US |
Effects of TSH on the adenylate cyclase-cAMP system and some parameters of intermediary metabolism were investigated in human thyroid carcinoma and adjacent normal thyroid tissue. Basal adenylate cyclase activity and cAMP concentrations were significantly higher in carcinomatous tissue. Basal [1-14C]glucose oxidation, 32Pi incorporation into phospholipids, and organification of iodide were similar in both tissues. Stimulation of cAMP by TSH was significantly greater in normal compared to carcinomatous tissue. In neither tissue was there a good correlation between TSH stimulation of adenylate cyclase activity and cAMP concentrations. The TSH stimulation of 32Pi incorporation into phospholipids by TSH was significantly greater in normal tissue. The mean effect of TSH on iodide organification and glucose oxidation was similar in normal and carcinomatous tissue. Although specific binding of TSH was demonstrated in both normal and carcinomatous tissue, it did not correlate very well with stimulation of adenylate cyclase activity. Hormones other than TSH also augmented adenylate cyclase activity in two of the carcinomas. In individual patients, the relative responsivity of carcinomatous tissue compared to normal was not always consistent when all of the metabolic parameters were considered. | US |
T3 binding to lymphocyte nuclei has been studied in normal individuals and in a patient (MaG) with peripheral resistance to thyroid hormone action. This syndrome is defined by the presence of hypothyroidism or euthyroidism with high plasma levels of thyroid hormone. T3 bound to a single set of binding sites in normal adult lymphocyte nuclei with a mean Ka of 8.9 +/- 7.1 x 109 M-1, and a capacity of 4.4 +/- 2.9 fmol/100 micrograms DNA. A single binding site was also disclosed in MaG's lymphocytes with a Ka of 0.43 x 109 M-1 and a capacity of 10.5 fmol/100 micrograms DNA. This low affinity was not due to the presence of high plasma T3 level in the patient, since administration of 100 micrograms T3 to normal adult volunteers induced the presence of two different binding sites. The mechanism responsible for this phenomenon is unknown. To binding was also studied using cultured fibroblasts which were incubated in serum-less medium before the binding experiments. One single binding site (Ka, 1.9 x 10(10) M-1, capacity, 12.9 fmol/100 micrograms DNA) was detected in normal fibroblast nuclei. In contrast, a curvilinear Scatchard plot was obtained when MaG's fibroblasts were used. This result could be compatible with the presence of either two different binding sites or negative cooperativity. In support of the latter possibility, Hill plots gave a number lower than unity. The results suggest that the syndrome of peripheral tissue resistance to thyroid hormone action due to a defect at the level of the nuclear receptor. The possible existence of similar syndromes due to an alteration at the level of a post-T3-binding mechanism is not eliminated. | US |
The DMS-79 continuous line of human small cell lung carcinoma cells, which produces immunoreactive (IR)-corticotropin (ACTH), -lipotropin (LPH), and -beta-endorphin (beta END), was found to produce IR-calcitonin (CT). Two major high molecular weight (HMW) forms of IR-CT were observed after gel exclusion chromatography under denaturing conditions (mol wt. approximately 7,000 and approximately 14,000), as well as a minor HMW IR-CT component (mol. wt. approximately 70,000). None of these IR-CT materials was extracted from DMS-79 medium by affinity chromatography using an ACTH antibody covalently bound to agarose. These results demonstrate ectopic production of HMW forms of CT and ACTH/LPH/beta END by human lung tumor cells in tissue culture, but do not support the existence of a common CT/ACTH/LPH/beta END precursor molecule. | US |
Five pregnancies were monitored for couples at-risk for having a child with some form of Niemann-Pick disease (NPD). Three of these were for the classic Type A form in which affected children usually have less than 1% of normal sphingomyelinase activity. Two of these pregnancies were terminated after the cultured amniotic-fluid cells were determined to have less than 1% of normal sphingomyelinase activity (0.4 and 0.6 nmole/mg protein/hr versus the control mean of 61.7). In the other pregnancy at risk for Type A NPD near normal activity was measured and it was continued to term. The two other pregnancies were monitored for couples in which severely affected children were found to have partially deficient sphingomyelinase activity (about 20% of normal) in cultured skin fibroblasts. Cultural amniotic-fluid cells from one of these pregnancies also had about 20% of control sphingomyelinase activity, but the woman underwent a spontaneous abortion soon after the cells were received and no studies on the fetus were done. The other sample was taken at the time of abortion for social reasons. In this case the cultured amniotic-fluid cells and cultured fetal skin fibroblasts gave normal sphingomyelinase activity. Enzymatic studies on tissues from the two fetuses predicted to be affected with Type A NPD confirmed the prenatal diagnosis. Studies of sphingomyelinase activity in the brains from these fetuses and from a child who died with Type A NPD indicated significant levels of activity when measured at pH 7.4 in the presence of magnesium. The higher level of the pH 7.4 sphingomyelinase activity in developing brain may indicate some important role in normal brain development. | US |
In order first to establish the disappearance t 1/2 of endogenous immunoreactive human beta-MSH (RIA-h beta MSH), which is now known to represent the lipotropins, human beta-LPH and human gamma-LPH, the plasma concentrations of RIA-h beta MSH, RIA-hACTH, and fluorogenic corticosteroids (cortisol) were measured before and during infusion of cortisol in three patients with primary adrenocortical insufficiency from whom steroid replacement had been withdrawn. The t 1/2 for RIA-h beta MSH ranged from 44-133 min (mean, 83), and for RIA-hACTH ranged from 20-51 min (mean, 40). On this basis, 30-min sampling intervals were chosen to measure plasma concentrations of RIA-h beta MSH, RIA-hACTH, and cortisol in three normal subjects for 24 h. Similar diurnal rhythms were observed for all three hormones. Highest values (58.0 +/- 5.8 pg/ml) for RIA-h beta MSH were observed at about the time of awaking and lowest values (15.0 +/- 2.1 pg/ml) shortly after retiring. The secretion of both RIA-h beta MSH and RIA-hACTH appeared to be episodic, with about 8-10 secretory episodes/24 h, and the timing of their secretory episodes appeared to be nearly identical. There was excellent correlation (P less than 0.001) between simultaneous concentrations of RIA-h beta MSH and RIA-hACTH in all three subjects. These results establish the presence of a diurnal rhythm in plasma lipotropins (RIA-h beta MSH) and suggest that roughly equimolar amounts of ACTH and LPH are secreted simultaneously by the pituitary under basal conditions in man. | US |
Total nucleic acid has been extracted from a human pancreatic insulinoma. Purification of the messenger RNA (mRNA) fraction by oligo-dT cellulose chromatography yielded 200 micrograms poly(A)-rich mRNA. This mRNA produced a 2-fold stimulation of protein synthesis in a wheat germ cell-free system. Analysis of the translation products by gel filtration chromatography (Biogel P-30) revealed nothing smaller than an acid-alcohol-soluble protein larger than bovine proinsulin. In contrast, insulinoma slices incubated with labeled amino acids synthesized smaller proteins which comigrated with bovine proinsulin and insulin. [3H]Leucine-labeled cell-free proteins were electrophoresed on NaDodSO4-urea polyacrylamide slab gels. In the presence of insulinoma mRNA, discrete proteins of 25,000 and 11,500 mol wt were synthesized. The 11,500 mol wt protein was specifically immunoprecipitated with antiinsulin serum. Thus, cell-free translation of human insulinoma mRNA yields an immunoreactive insulin larger than proinsulin, which is the same size as fish and rat preproinsulins recently described. | US |
Aphagia and adipsia of equivalent duration were produced by knife cuts along the lateral border of the hypothalamus (PH cuts), or the medial surface of the globus pallidus (MP cuts) in male albino rats. Striatal dopamine (DA) was reduced by 75% in animals with PH cuts but only 50% by MP cuts. Hypothalamic norepinephrine was reduced 25% by PH cuts and was unaffected by MP cuts. Aphagia and adipsia were positively correlated with DA depletions only in rats with PH cuts. Presurgical catecholamine depletions produced by chronic injections of alpha-methyl-p-tyrosine did not alter the duration of aphagia or adipsia resulting from these knife cuts. However, following recovery of ingestive behavior, rats with PH and MP cuts were supersensitive to the anorexic effects of the dopamine-beta-hydroxylase inhibitor, diethyldithiocarbamate. Exaggerated anorexia was also observed after DA blockade by haloperidol or alpha-adrenergic blockade by phenoxybenzamine. The most pronounced effects of catecholamine blockade were observed in rats with PH cuts. | US |
A group of estrogen-primed, ovariectomized rats was adrenalectomized and tested for sexual receptivity following hypothalamic implantations of PGE2. The combination of PGE2 and adrenalectomy led to severe debilitation as manifested by greatly reduced open-field activity scores and inhibition of estrogen and progesterone induced sexual receptivity. Neither exogenous progesterone nor corticosterone was able to restore these behaviors to normal levels. A mechanism involving PGE2 and adrenalectomy-induced transient ischemia was discussed as a possible cause of the debilitation. | US |
A variety of cultural conditions were examined to determine the relationship between pyruvate kinase isozyme patterns and morphology in Mucor racemosus. The results indicate that M. racemosus has two isozymes of pyruvate kinase, form A and form B, which are clearly separable on ion-exchange columns (diethylaminoethyl-cellulose). Addition of glucose to cultures growing on amino acids in air resulted in the induction of form A and the termination of form B synthesis. Cycloheximide added at the same time as glucose blocked the formation of form A but did not interfere with the termination of form B synthesis. Removal of glucose resulted in termination of form A synthesis and the induction of form B. Cycloheximide blocked the induction of form B and did not interfere with the termination of form A synthesis. The data show that the isozyme type is not directly related to morphology, but depends only on the presence or absence of glucose. | US |
The expression of several functional properties of the products of the bfe and tonB genes in Escherichia coli was measured after the specific termination of the synthesis of the products of these genes. This was accomplished by the use of a temperature-sensitive amber suppressor mutation, which allowed control, by manipulation of the growth temperature, of the level of product formed from suppressible mutant alleles of the bfe or tonB gene. The bfe product is an outer membrane receptor protein for vitamin B12, the E-colicins, and bacteriophage BF23. The identity of the tonB product is unknown, but it is necessary for a subsequent step of uptake of vitamin B12, iron chelates, all of the group B colicins, and bacteriophages T1 and phi 80. Results from a different experimental system had shown that the termination of expression of the bfe locus was rapidly followed by loss of sensitivity to colicins E2 and E3 and, subsequently, to bacteriophage BF23. This was confirmed with this experimental system. Receptors that were no longer functional for colicin or phage uptake remained fully effective for B12 uptake, showing that receptors are stable on the cell surface. This supports previous contentions for the presence of different functional states for colicin receptors. The functional properties of the tonB product, measured by B12 uptake or sensitivity to the group B colicin D, were unstable, declining extensively after cessation of its synthesis. | US |
Conditions for continuous culture of Escherichia coli K-12 His- Thi- under glucose limitation were established. Both the capacity for respiration, at D greater than 0.2/h, and specific activity of superoxide dismutase increased as a function of specific growth rate, whereas peroxidase and catalase were either invariant with or inversely related to this growth rate. The abrupt increase in the availability of glucose, as a means of elevating the growth rate, was followed by an increase in superoxide dismutase, which reached a plateau before there was a significant increase in the growth rate. Thus, an increase in superoxide dismutase appeared to be a prerequisite for an increase in the rate of growth. Cells that had higher levels of superoxide dismutase, because of varying specific growth rates, were more resistant to the toxicity of hyperbaric oxygen. Superoxide dismutase thus behaved like an essential defense against the toxicity of oxygen. Sensitivity towards streptonigrin increased with specific growth rate in the range of 0.09 to 0.25/h but decreased with further increases in the growth rate. Since this antibiotic has been shown to shunt electrons to oxygen, with concomitant production of O2-, these results indicated a progressive deficiency of reducing power at growth rates below 0.25/h and a surfeit of reducing power with progressively greater protection against O2- by superoxide dismutase at growth rates greater than 0.25/h. | US |
The rates of movement of Na+, Rb+, Cl- and HCO3- from plasma to endolymph were studied in the elasmobranch fish, Squalus acanthias, by use of the appropriate isotopes. Rb+ was used as a marker for K+. The half-times to equilibrium for Na+, Rb+ and Cl- were about 100 hours; for HCO3- it was 6 hours. The equilibrium ratios, endolymph/plasma, are Na+ 0.87, K+ 26, Cl- 1.37, HCO3- 1.47. Carbonic anhydrase inhibition decreased the rate of HCO3- accumulation, suggesting that the process is actually the formation of endolymphatic HCO3- from plasma or tissue CO2. Increase in plasma pCO2 elevates endolymph HCO3- concentration. The secretory tissue contains carbonic anhydrase and Na-K-ATPase. These and other data suggest that a dominant feature of endolymph chemistry may be HCO3- formation linked in some fashion with K+ transport, through rates catalyzed by these two enzymes. | US |
Cleavage of chloroplast deoxyribonucleic acid (DNA) of Euglena gracilis Z with restriction endonuclease RI from Escherichia coli (EcoRI) yielded 23 bands upon electrophoresis in gels of agarose. Four of the bands contained twice the stoichiometric amount of DNA. One of these bands contained two similarly sized fragments. The sum of the molecular weight of the 24 different fragments equaled the molecular weight of the circular molecule. The restriction fragments had different buoyant densities, with four having distinctly heavy densities in CsCl. Restriction fragments with a high buoyant density were preferentially lost when broken chloroplast DNA was purified by equilibrium density gradient centrifugation. Hybridization of chloroplast ribosomal ribonucleic acid to intact chloroplast DNA determined that there are two cistrons for 16S and 23S ribosomal ribonucleic acid. These two cistrons are located on six restriction fragments, all of which have buoyant densities greater than the intact molecule of chloroplast DNA. | US |
Molecular cloning techniques were used to construct hybrid Escherichia coli lambda phage and isolate Col E1 factors that carried the cheB region of the E. coli genome. The products of these genes were examined by using a series of deletions in the phage to stimulate specific polypeptide synthesis in ultraviolet-irradiated cells and by using Col factor to program protein synthesis in minicells. Seven flagellar related polypeptides were synthesized. Three of these with apparent molecular weights of 38,000, 28,000, and 8,000 were associated with the cheB region; three polypeptides 63,000, 61,000, and 60,000 were associated with the region that maps between cheB and cheA. These bands were referred to as the triplet group. We suggest that these polypeptides are the same as the methyl-accepting chemotaxis protein described by Kort et al. (Proc. Natl. Acad. Sci. U.S.A. 72:3939-3943, 1975). Another polypeptide with a molecular weight of 12,000 is associated with the cheA region which also produces at least three gene products. We conclude that the cheA-cheB region in E. coli is complex. Further genetic and biochemical analyses are required to describe all of these products. | US |
A procedure is described that selects for the insertion of transposable antibiotic resistance elements in a variety of recipient replicons. The selected translocation procedure, which employs a plasmid having a temperature-sensitive defect in replication as a donor of transposable genetic elements, was used to investigate certain characteristics of the translocation process. Our results indicate that translocation of the Tn3 element from plasmid to plasmid occurs at a 10(3)- to 10(4)-times-higher frequency than from plasmid to chromosome. In both cases, continued accumulation of Tn3 on recipient genomes is prevented by development of an apparent equilibrium when only a small fraction of molecules in the recipient population contain Tn3. An alternative method for estimation of translocation frequency has shown that the translocation process is temperature sensitive and that its frequency is unaffected by the presence of host recA mutation. Insertions of Tn3 onto the 65 X 10(6)-dalton R6-5 plasmid in Escherichia coli are clustered on EcoRI fragments 3 (8 of 23 insertions) and 9 (7 of 23 insertions), which contain 12 and 5%, respectively, of the R6-5 genome. The occurrence of multiple insertions of Tn3 within EcoRI fragment 9, which contains the IS1 element and a terminus of the Tn4 element, is consistent with earlier evidence indicating that terminal deoxyribonucleic acid sequences of already present transposable elements may provide recognition sequences for subsequent illegitimate recombinational events. | US |
The dominance of dnaA+ to the dnaA508 mutation was complete and was unaffected by the presence of a copy of the chromosomal replication origin on the episome. These results prove that the dnaA gene of Escherichia coli produces a diffusible product. | US |
Six children (7 to 16 years of age) with pelvic osteomyelitis are described. Sites of involvement included the pubis in three patients, the ilium in two patients, and the ischium in one patient. All were right-sided. Each patient presented with a history of fever and an abnormal gait. In four, the point tenderness indicated the site of bony involvement. All patients had pain on abduction but free passive range of motion of the hip. Soft tissue swelling was present on admission pelvic roentgenograms in five patients. Intravenous pyelogram revealed deviation of the bladder toward the midline in each of four patients studied. Roentgenographic changes typical of osteomyelitis developed in four patients ten days to ten weeks after onset of symptoms. In four patients in whom an organism was identified, Staphylococcus aureus was isolated from blood and/or bone. All isolates were methicillin-sensitive and two were penicillin-sensitive. Purulent material was drained from three of the five patients who underwent surgical exploration of the pelvis. All patients received parenteral antistaphylococcal therapy for 3 to 5 1/2 weeks (mean, 4 weeks). Oral antibiotics were given to five patients for an additional 3 to 14 weeks. All patients recovered completely. | US |
The rate of appearance, in a newly formed heterokaryon population, of cells bearing completely intermixed mouse and human surface antigens may be used to estimate diffusion constants for antigens on individual cells. From this estimate, it appears that the surface antigens in most cells do not diffuse at the rate expected, but rather move more slowly, by a factor of ten or more, than expected from either measured or calculated diffusion constants for proteins freely mobile in the plane of a lipid membrane. Differences in diffusion rates between cells are not due to effects of Sendai virus, or of trypsin. Restrictions on diffusion are apparently not due to cytochalasin B- or Colcemid-sensitive elements. | US |
Electrophoretic data from both sodium dodecyl sulfate-polyacrylamide gels (SDS-PAGE) and acid-urea gels reveal a protein in purified murine mammary tumor virus (MuMTV) which co-migrates with purified chick skeletal muscle actin. 125I-labeling of intact and disrupted virus preparations shows that the actin-like protein is not artifactually adsorbed to the outside of virions during isolation. Quantitative SDS-PAGE and examination of negatively stained preparations show that the actin cannot be accounted for by a contaminating population of virus-free vesicles. The ultrastructure of mammary epithelial cells and of Rous sarcoma virus-transformed chick embryo fibroblasts shows that virus extrusion is associated with filament-containing cellular processes. In particular, MuMTV is released from the ends of long microvilli which contain a bundle of 6-8-nm microfilaments and share other structural features with intestinal microvilli. We suggest that virus nucleoids require an interaction with host cell contractile proteins for their extrusion from the cell. | US |
This study involved the application of discrimination behavior for the study of effects of environmental contaminants on the behavior of laboratory animals. Polybrominated biphenyl (PBB) was evaluated for effects on the acquisition and performance of a simple auditory discrimination by rats. Methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK) and carbon monoxide (CO) were evaluated for effects on a delayed match-to-sample discrimination task in the juvenile baboon. All of the contaminants slowed response times and increased extra responses. These findings suggest that discrimination behavior may be of value for the evaluation of environmental contaminants for effects on the central nervous system. | US |
Sister chromatid exchange (SCE) frequencies were studied in differentially stained chromosomes from lymphocytes of 17 patients with viral disease. The mean SCE score for the patients was 8.7 +/- 2.9 standard deviations. SCE scores were significantly elevated in the patients compared with the controls (p less than 0.01); however, variability in SCE means was observed in the patients. SCE elevations were also present in long term cultured Epstein Barr virus positive human B lymphocytes. | US |
1. Most of the lipids in the hemolymph of the spiny lobster, Panulirus interruptus, were associated with a high density lipoprotein (HDL3). The lipid of this lipoprotein was composed of phospholipid (88%), sterol (4%) and triglyceride (3%). 2. In animals fed 14C-labeled triglyceride radioactivity was not seen in the serum until 12 hr after feeding. Most of this serum radioactivity was associated with phosphatidyl choline. 3. Electron micrographs showed that negatively stained high density lipoproteins of the lobster had a polymorphic appearance. | US |
1. Carbohydrate composition of serum low and high density lipoproteins obtained from 5 nonhuman primate species (chimpanzee, patas, baboon, rhesus, and spider) and humans was studied. 2. Individual lipoproteins were isolated from pooled sera of each species by ultracentrifugal flotation between the densities 1.019-1.063 for LDL-2; 1.063-1.12 for HDL-2; and 1.12-1.21 for HDL-3. After delipidation, sialic acid, fucose, glucosamine, mannose, galactose, and glucose were determined on apo LDL-2, apo HDL-2, and apo HDL-3. 3. Glucosamine, galactose, and mannose constituted a major component of the sugars in apo LDL-2, with similar relative proportions in all species. Sialic acid, fucose, and glucose formed a minor component, the proportions of which varied greatly among the species. 4. Unlike apo LDL-2, sialic acid, fucose, and glucosamine constituted the bulk of the sugars in apo HDL-2 and apo HDL-3. Mannose, galactose, and glucose were minor components, with galactose predominating. 5. Qualitative differences were observed in electrophoretic mobilities of apo HDL-2 and apo HDL-3 on polyacrylamide gel. One faster moving band was unique to chimpanzee. 6. Intraspecies differences in the content of sialic acid and fucose of apolipoproteins may be related to lipoprotein metabolism and species susceptibility (or resistance) to either spontaneous or diet-induced atherosclerosis. | US |
1. Crude enzyme preparations from Hymenolepis diminuta contained galactokinase, galactose 1-phosphate uridyl transferase and UDPgalactose 4-epimerase activity, although their specific activities were low. 2. Galactose 1-phosphate non-competitively inhibited galactose phosphorylation. This inhibition, together with the low specific activities of the enzymes in the pathway of galactose utilization, probably accounts for the inadequacy of galactose as a main nutritive carbohydrate for development of the worm. | US |
1. Glucagon stimulated gluconeogenesis from both [U-14C]lactate and [14C]xylitol in isolated perfused mouse liver. 2. Addition of cyclic AMP also stimulated gluconeogenesis from [U-14C]lactate. 3. Glucagon caused a rapid (2.5 min) 12-fold increase in hepatic cyclic AMP but not cyclic GMP concentration. 4. Glucagon caused a rapid and stable decrease in hepatic fructose 1,6-diphosphatase activity measured in vitro. 5. The results are interpreted to indicate that glucagon stimulates hepatic gluconeogenesis in mice via cyclic AMP by two different mechanisms: (a) increased substrate uptake (i.e. utilization) and (b) increased gluconeogenic efficiency (i.e. inhibition of alternate substrate fates). | US |
1. Taste receptors for L-alanine in the channel catfish Ictalurus punctatus have been partially characterized. The binding activity, which is localized to a sedimentable fraction (Fraction P2), was assayed with L-[3H]alanine as the ligand. 2. Addition of HgCl2 or p-mercuribenzoate to the assay at 0.1-1 mM markedly inhibited binding. The effect was not reversible and was unaffected by increased L-alanine in the binding assay. 3. The sulfhydryl reagents iodoacetate, 5,5'-dithiobis(2-nitrobenzoic acid), arsenite, and N-ethylmaleimide did not show appreciable inhibition of binding. The results suggest that the inhibitory effect of mercurials is not on specific sulfhydryl groups at alanine-binding sites. 4. Treatment of Fraction P2 with phospholipase C decreased binding activity and treatment with trypsin led to increased binding activity. | US |
1. The effect of propylthiouracil (PTU)-induced hypothyroidism on carbohydrate and lipid metabolism was studied in the chick embryo. 2. A single dose of PTU (250 micrograms/embryo) was administered on day 11 and embryos sacrificed on day 20 of incubation. 3. Thyroid glands were significantly enlarged (6 fold) by PTU administration. 4. Increased thyroid weight was associated with growth retardation and decreased plasma thyroxine levels. 5. Plasma glucose level was lower and phospholipids were significantly higher in the hypothyroid embryo. 6. Liver lipid concentrations in the control and hypothyroid embryos were not different but were significantly higher in both groups when compared to previously reported values in the young chick. 7. In contrast to PTU treatment after hatching, liver glycogen levels were not increased in the hypothyroid chick embryo. This was attributed to the high lipid nutrient condition of the chick embryo since a high lipid diet in the young chick decreased hepatic glycogen accumulation significantly. | US |
The authors studied the effects of oral loading with 5-HTP on REM fragmentation in a group of alcoholics who were abstinent following acute ethanol withdrawal. Decreased fragmentation was found in the majority of subjects, and those subjects with low baseline REM efficiency (i.e., greater fragmentation) showed more improvement from the drug than did subjects who were less impaired initially. The authors suggest that there is an organic decrement of serotonin during ethanol withdrawal which is partially reversed by 5-HTP loading. | US |
1. Tissue levels of adenosine 3', 5'-cyclic monophosphate (c-AMP) were determined by a protein binding assay in mixed populations of the free living nematode Panagrellus redivivus. 2. The values were 2.6 pmoles/mg dry weight (range 1.3-3.4 pmoles). 3. The identity of the c-AMP assayed was confirmed by both anion exchange and TLC as well as enzymatic degradation. | US |
1. Tissue levels of guanosine 3',5'-cyclic monophosphate (c-GMP) were determined by radioimmunoassay in mixed-age populations of the free living nematode Panagrellus redivivus. 2. Cyclic-GMP was identified by chromatography (ion exchange and thin-layer) and by enzymatic degradation. | US |
1. The larval high density lipoprotein (HDL) from the hemolymph of Manduca sexta, isolated by density gradient centrifugation, contains 61% protein, 37% lipid and 2% carbohydrate. 2. The molecular weight of HDL is 6 x 10(5), with two apoproteins of 2.85 x 10(5) and 8.1 x 10(4) daltons. 3. The large apoprotein is destroyed by trypsin treatment of the particle, while the small one is not. 4. Calculations based upon size and composition show that this particle is very different in structure from mammalian lipoproteins. It is proposed that a portion of the apoprotein occupies the central core region. | US |
1. Glucose-6-phosphatase (EC 3.1.3.9 D-glucose-6-phosphate phosphohydrolase) was found to be localized mainly in the endoplasmic reticulum (microsomal fraction) of all species of vertebrate liver tissue examined. 2. Hepatopancreas tissue from gastropod molluscs was found to be unique in showing the localization of glucose-6-phosphatase in the cytosol (soluble fraction). | US |
The in vitro effects of asbestos fibers on the growth and viability of CHO cells, an epithelioid cell line derived from Chinese hamster ovary, and on K-22 cells, an epithelial cell line derived from rat liver, have been studied. Relatively low concentrations of asbestos (10 micrograms/ml) were quite cytotoxic to both cell types. A sample of chrysotile asbestos was more toxic than samples of crocidolite or amosite. The toxic factor could not be extracted from the asbestos and toxicity occurred only if there was physical contact between the fibers and the cells. Although the phorbol ester class of tumor promoters induces the synthesis of plasminogen activator in various cell cultures, asbestos did not induce this protease in epithelioid or fibroblast cell cultures. The results obtained are compared to previous in vitro results obtained with fibroblast or macrophage cultures and are discussed in terms of their possible relevance to asbestos-induced fibrosis and tumorigenesis. | US |
Pyrimidine 5'-nucleotidase (P5N, EC 3.1.3.5) appears to be a sensitive index of exposure to low level lead. In 21 children 2 to 5 years old with blood leads of 7 to 80 micrograms/dl there was a negative linear correlation of blood lead and red cell P5N: r = -0.60 (P less than 0.01), Y = -0.11X + 12.3. In rats, the enzyme assay was quantitatively similar to that of the human. A treatment group of 12 rats received lead acetate, 36 mg/kg/day, of lead as 0.17 M lead acetate for 24 days. The blood lead of treated rats increased from the control value of 8.3 +/- 1.3 to 36.0 +/- 0.5 on day 24; P5N decreased from 18.3 +/- 0.8 units to 9.0 +/- 1.0 and was below control values at a blood lead of 25. There was a significant negative linear correlation of blood lead and P5N: r = -0.85; n = 17; P less than 0.001; Y = 0.34X + 20.9 that was independent of the correlationship with the reticulocytes. At these levels of blood lead and P5N there was no significant change in the hexokinase, hemoglobin or red cell count and no evidence of stippling. | US |
The interaction of the potential-sensitive extrinsic probe oxonol VI with beef heart submitochondrial particles has been investigated under time resolved and equilibrium conditions. The time course of the probe absorption spectrum red shift induced by ATP or NADH injection into a suspension of submitochondrial particles in a dye solution is biphasic, consisting of a faster process described by a second-order rate law with k2 approximately 3 x 10(5) M-1 sec-1. For the ATP pulse experiments, the slower process follows first-order kinetics with k1 approximately 0.3 sec-1. In oxygen pulse experiments to an anaerobic dye-particle system, the slower process is not significantly developed due to rapid depletion of the oxygen, but the faster process follows second-order kinetics with the same rate of the oxygen, but the faster process follows second-order kinetics with the same rate constant as for the ATP and NADH cases. Evidence for permeation of the submitochondrial particle membrane by oxonol VI has been obtained; the slower process is interpretable as describing the permeation of the membrane bilayer. The results of the time-resolved work are consistent with a mechanism involving a redistribution of the dye from the bulk phase to the particle membrane. The value of the second-order rate constant for passive binding of the dye to submitochondrial particles is not compatible with a mechanism proposed to explain the microsecond probe response times in bilayer and excitable membrane experiments nor are such rapid signals observed in the oxonol VI-submitochondrial particle system. | US |
Specific serum binding of 25-hydroxy-cholecalciferol (25-OHD3) was measured by saturation analysis in rats of various ages, and during vitamin D deprivation. The serum binding capacity for 25-OHD3 was observed to increase until age 6-8 weeks, then decline and remain stable thereafter at 3.7 x 10(-6) M. The 25-hydroxyvitamin D (25-OHD) concentration decreased in serum from rats fed vitamin D-free diet (t1/2 = 7 days). Rats fed 2 IU of vitamin D3/g of diet maintained stable serum levels of 25-OHD at 10-12 ng/ml. Serum binding capacity and affinity for 25-OHD3 was not affected by vitamin D deprivation or hypocalcemia. In addition, the binding affinity did not differ as a function of age (Kd = 3.3 x 10(-9) M). Since normal serum concentrations of 25-OHD in the rat are 2-5 x 10(-8) M, only 1-2% of the serum binding sites for this sterol are occupied under physiological conditions. | US |
Unlike in all other thyroid preparations, exposure of dog thyroid cells in long-term monolayer culture to iodide (10(-7) to 10(-3) M for up to 19 h did not blunt the subsequent adenosine 3', 5'-cyclic monophosphate (cAMP) response to thyrotropin (TSH) stimulation. This lack of effect of iodide was observed even when confluent thyroid cells were "follicularized" by the action of TSH in the culture medium. Preincubation of these cells in thyroxine (T4) and triiodothyronine (T3) was similarly without effect on the subsequent cAMP response to TSH. Study of thyroid cells during the early phase of primary culture demonstrated that inhibition by iodide (10(-4) M) of the cAMP response to TSH occurred after 7 h but was lost after 48 h of cell culture. This inhibitory effect of iodide was prevented by the inclusion of methimazole in the preincubation medium. As with iodide-insensitive cells, T4 and T3 were without effect on the cAMP response to TSH in iodide-sensitive thyroid cells. Exposure of iodide-insensitive thyroid cells to iodide-containing medium obtained after 2 h of incubation with dog thyroid slices, as well as to medium enriched with the 100,000 g supernatant fraction of homogenates prepared from these thyroid slices, did not restore the inhibitory action of iodide. However, iodide-sensitivity of the cAMP response to TSH was restored by preincubation of iodide-insensitive cells in 10(-4) M iodide plus an H2O2-generating system (glucose-glucose oxidase). These data suggest that T4 and T3 are not organic iodine inhibitors of the thyroid cAMP response to TSH. In addition, they provide evidence against the existence of a soluble, freely diffusible, organic iodine inhibitor of thyroid adenylate cyclase. The loss of sensitivity to iodide inhibition of adenylate cyclase that occurs in thyroid cells shortly after initiation of primary culture appears to be related to a defect in the cellular organification mechanism, possibly the H2O2-generating system. | US |
Plasma concentrations of 25-hydroxyvitamin D3 (25-OHD3) and 1 alpha,25-dihydroxyvitamin D3 (1 alpha, 25-(OH)2D3) in growing chicks and weanling rats were measured by a new radioreceptor assay to determine the effects of varying dietary levels of vitamin D3. The plasma concentration of 25-OHD3 fell from 14.1 ng/ml in 1-day-old chicks to undetectable levels after 3 weeks on a rachitogenic diet. Circulating 1 alpha,25-(OH)2D3 hormone also decreased from 8.9 ng/100 ml to undetectable levels at 3 weeks in these chicks. Chicks receiving an optimal supplement of vitamin D3 (1.4 IU/g diet) for three to four weeks had plasma 25-OHD3 and 1 alpha,25-(OH)2D3 levels of 21-35 ng/ml and 5.1-7.5 ng/100 ml, respectively. Nutritional supplementation with a 50-fold excess of vitamin D3 (70 IU/g diet) elicited a substantial increase in plasma 25-OHD3 to 87-130 ng/ml, while plasma 1 alpha,25-(OH)2D3 was not increased. Increasing dietary calcium from 1.4 to 2.8% did not alter the circulating level of vitamin D3 metabolites in chicks fed 1.4 IU of vitamin D3/g diet. Direct measurement of the renal 25-OHD3-1 alpha-hydroxylase in vitro, showed that lowering dietary calcium or exclusion of vitamin D3 stimulated the biosynthesis of 1 alpha,25-(OH)2D3, but raising calcium did not alter the enzyme activity. It is concluded that the circulating concentration of the 1 alpha,25-(OH)2D3 hormone in the chick is unaffected by abnormally high intakes of vitamin D3 or calcium, but the renal production of the hormone increases during vitamin D3 or calcium deprivation. Additional studies in rats fed a diet supplemented with either 2 or 1000 IU of vitamin D3/g verify that the circulating concentration of 25-OHD3 is markedly increased when the dietary intake of vitamin D3 is elevated. Moreover, 1 alpha,25(OH)2D3 is not increased under these conditions, but actually falls significantly when the dietary level of vitamin D3 is raised from 2 to 1000 IU/g. These studies in both the chick and rat indicate that dietary vitamin D3 excess enhances circulating 25-OHD3, probably because the vitamin D3-25-hydroxylase enzyme is not strigently controlled. The fact that the circulating 1 alpha,25-(OH)2D3 is not concomitantly increased may reflect either decreased synthesis or increased utilization of the 1 alpha,25-(OH)2D3 sterol. | US |
Comparisons between automated suprathreshold static perimetry and manual kinetic perimetry were performed for 226 eyes with glaucoma or ocular hypertension, and 147 eyes with other optic nerve disease. Both techniques produced similar high detection rates for glaucomatous visual field defects, whereas suprathreshold static perimetry performed significantly better than kinetic testing in optic nerve disease other than glaucoma. It is concluded that automated suprathreshold static perimetry is an excellent quantitative screening technique for detecting visual field defects. | US |
Fifty-eight patients with orbital rhabdomyosarcoma were treated with irradiation alone (25) or irradiation and chemotherapy (33) with follow-ups of 6 months to 14 years (mean 5.2 yr). At present, 74% are alive and 26% have died. Local control of the tumor was accomplished in 91% of cases. When local sinuses were invaded the survival rate was 55%. Chemotherapy appears to be of greatest value when disease is limited to the orbit. Irradiation or irradiation and chemotherapy should now be the treatment of choice for orbital rhabdomyosarcoma. | US |
The effect of 2-mercaptoethanol (2-ME) and alpha-thioglycerol (alpha TG) on proliferation and polyclonal activation of lymphocytes was studied in cultures of spleen cells from C3H mice. Inclusion in serum-free or serum-containing medium of the optimal concentration (5 x 10(-5) M) of either 2-ME or alpha TG resulted in highly significant uptake and incorporation of tritiated thymidine ([3H]TdR) into DNA and in morphological blast transformation. These phenomena were dose-dependent, with both lower and higher doses causing less marked effects. The kinetic peak of these responses was found to occur at day 3 of culture. Improved cellular viability could not explain these results, because by day 3 there was no significant difference in viability between cells cultured in the presence or absence of 2-ME. 2-ME evoked a proliferative response in cultures of congenitally athymic (nu/nu) spleen cells that exhibited a similar but lower dose-response profile compared with that of heterozygous (nu/+) littermates. Cultures of bone marrow-derived (B) lymphocytes, generated by treatment of spleen cells with rabbit antithymocyte serum and complement, incorporated [3H]TdR to a degree at least equal to that of normal spleen cell cultures. Thymus-dependent (T) cells did not support significant 2-ME, alpha TG, or Concanavalin A responses in the absence of serum. However, when cultured in 5% fetal calf serum, definite T-cell responses occurred, though always of a lower magnitude than B-cell responses in this system. When the enriched B-cell and T-cell preparations were co-cultured, a synergistic response was noted. Macrophage dependency of the 2-ME and alpha TG effect was shown to be minimal. It is likely that the greater effectiveness of alpha TG relative to 2-ME is due to differences in the chemical structure of these two thiol compounds. The advantages of utilizing 2-ME and alpha TG as probes in the study of lymphocyte activation are evaluated and their possible mechanisms of action are discussed. | US |
A sensitive procedure employing limiting dilution of activated lymphocytes and 51Cr release from highly labeled target cells was used to derive minimal estimates of the absolute frequency of cytotoxic T lymphocytes (CTL) present in a population of mouse lymphocytes activated to alloantigens of the major histocompatibility complex in bulk mixed lymphocyte cultures. From this figure (0.7-1.2%), the maximal rate of target cell killing could be calculated to be approximately 4 targets/CTL/hour. | US |
Using limiting dilutions of responding cells in mouse mixed leukocyte cultures, we obtained direct estimates of the minimum frequency of precursors of cytotoxic T lymphocytes (CTL.P) for a variety of antigens. Depending on the strain combination, there were as many as 4-15 CTL.P reactive to DBA/2 among 10(4) lymph node cells. Taking into account that only 5-10% of peripheral T lymphocytes have the potential to develop into cytotoxic T lymphocytes (CTLs) (6), this implies that at least 1-2% of all CTL.P are responsive to any given H-2 haplotype difference. Precursors of cytotoxic cells thus have the same high frequency of cells reactive to alloantigens of the major histocompatibility complex as found among proliferating cells in graft-vs.-host reactions and mixed lymphocyte interactions. The frequencies of CTL.P reactive to xenoantigens (rat) or trinitrophenyl-modified self were less than half the frequency of alloreactive CTL.P. A minority of the CTL.P specific for one H-2 haplotype were also reactive to a third party H-2 haplotype, presumably on the basis of recognition of shared determinants. By dilution of sensitized cells from single microcultures, it was shown that a single CTL.P undergoes a minimum of three to four cell divisions and generates at least 8-16 CTLs after antigenic activation. | US |
Inoculation of rabbit anti-idiotypic (anti-id) antibodies suppresses the subsequent appearance of a cross-reactive idiotype (CRI) associated with the anti-p-azophenylarsonate (anti-Ar) antibodies of A/J mice. Such suppressed mice produce normal concentrations of anti-Ar antibodies which lack the CRI, but against which anti-id antisera can be prepared. The anti-Ar antibodies of an individual, suppressed mouse do not in general share idiotype with anti-Ar antibodies of other A/J mice, either suppressed or nonsuppressed. The present experiments were undertaken to quantitate several "private idiotypes" in a large number of hyperimmunized A/J mice. Anti-Ar antibodies of three mice, suppressed for the CRI, were labeled with 125I and subjected to isoelectric focusing. Four single peaks, that were over 90% reactive with autologous antiid, were randomly selected for use as ligands in a radioimmunoassay, and ascitic fluids containing anti-Ar antibodies from 181 A/J mice were tested as inhibitors. Two of the four idiotypes could not be detected in any mouse other than the donor. The concentration of the idiotype was less than 1 part in 1,250 to less than 1 part in 25,000 of the anti-Ar antibody population; these are minimum values. A third idiotype was detected in 3 of the 181 mice, but at very low concentrations. The fourth idiotype was present in 28% of the mice, again at a low concentration. The data support the existence of a very large repertoire of anti-Ar antibodies in the A/J strain and are consistent with a process of random somatic mutation for generating diversity in hypervariable regions. It is proposed that the cross-reactive idiotype may be controlled by a germ line gene or a gene related to a germ line gene through a small number of somatic mutations; and that the idiotypes that were not detectable in other mice were the products of genes that had undergone extensive mutations, with a low probability of recurrence in other mice. | US |
Specificity of cytotoxic T-cell function was investigated for a range of different influenza viruses. T cells from mice immunized with A or B strain influenza viruses, or with vaccinia virus, showed reciprocal exclusion of cytotoxicity. Extensive cross-reactivity was, however, found for lymphocyte populations from mice infected with a variety of serologically distinct influenza A viruses, though serum antibodies did not cross-react when tested in a radioimmunoassay using comparable target cells as immunoadsorbents. This apparent lack of T-cell specificity was recognized for immune spleen cells generated after intraperitoneal inoculation of high titers of virus, and for mediastinal lymph node populations from mice with pneumonia due to infection with much less virus. The phenomenon could not be explained on the basis of exposure to the chicken host component, which is common to A and B strain viruses. However, not all of the virus-immune T-cell clones are cross-reactive. Competitive-inhibition experiments indicate that a considerable proportion of the lymphocyte response is restricted to the immunizing virus. Even so, the less specific component is significant. Also, exposure to one type A virus was found to prime for an enhanced cell-mediated immunity response after challenge with a second, serologically different A strain virus. | US |
Irreversible adsorption of a virulent phage, phage A25, to heat-killed streptococci, groups A, G, and A variant, has been achieved. Adsorption reflected the observed host range for phage A25 in that heat-killed group B cells were not able to inactivate the phage. Broken cells, cell walls, and peptidoglycan prepared from a group A strain K56 failed to adsorb the phage irreversibly, but retained the potential to carry out reversible adsorption. Experimental data including electron microscopy have demonstrated the specificity of reversible adsorption and have identified the peptidoglycan as a necessary cellular component of the receptor. The sensitivity of whole cells and purified peptidoglycan to muralytic enzymes suggests that the cell wall and peptidoglycan must be intact for optimal adsorption. In general the results are explained by postulating that adsorption of A25 phage particles to group A cells occurs by a two-step process; the first step involves recognition and reversible binding of the phage tail to the cell wall peptidoglycan, the second step is an irreversible reaction catalyzed by a yet unidentified cellular component which is destroyed when cells are ruptured. | US |
The RFV strain of the Friend virus complex induces an erythroleukemia that spontaneously regresses. The tropism of regressing Friend virus complex (RFV), which is conferred by its helper MuLV component, MuLV-RF, is different from that of the conventional virus strain, CFV. RFV is NB-tropic and CFV is N-tropic. Passage of nonregressing CFV through Fv-1 incompatible Swiss/ICR mice changed the tropism of CFV from N to NB and resulted in a virus strain which induced erythroleukemia that regressed. Passage of NB-tropic CFV back through Fv-1 compatible mice maintained NB-tropism and regression. Altering the quantity or type of helper MuLV in RFV complex by addition of Ri-MuLV inhibited regression in proportion to the amount of added Ri-MuLV. These studies indicate a relationship between a change in virus tropism to NB by passage in certain hosts (e.g., Swiss/ICR mice) and the ability of Friend virus to induce erythroleukemia that spontaneously regresses. MuLV-RF isolated from the RFV complex induced lymphocytic leukemia in newborn mice which regressed and caused the regression of CFV-induced erythroleukemia. MuLV-RF is NB-tropic, contains no spleen focus-forming virus (SFFV) activity and helps SFFV form spleen foci in genetically restrictive mice. Pseudotype viruses were prepared, consisting of MuLV-RF, or other MuLV's, and SFFV derived from FV-B. The pseudotype viruses each acquired the tropism of the MuLV used in rescue. The pseudotype prepared with MuLV-RF or another NB-tropic MuLV-F, but not the virus obtained by rescue with N-tropic MuLV-F, induced erythroleukemia that spontaneously regressed. These studies demonstrate that the ability of RFV to induce erythroleukemia that spontaneously regresses is due to its helper MuLV component. | US |
Phagocytosis of bacteria stimulates "professional" phagocytes to produce and release endogenous pyrogen (EP), the protein that mediates fever. To determine whether "nonprofessional" phagocytes also have this capacity, mouse and human fibroblasts and HeLa cells were cultured after ingestion of latex or chicken erythrocytes (CE), and EP release into culture supernate measured by mouse assay. No detectable pyrogen was released by these cell types after phagocytosis, whereas both latex and CE stimulated EP production by cultured mouse macrophages. These studies support the hypothesis that only professional phagocytes of bone marrow origin synthesize EP and induce fever. | US |
Thymus-dependent (T) lymphocytes from (2 x 13)F1 hybrid guinea pigs immunized to ovalbumin (OVA) in complete Freund's adjuvant can be stimulated to proliferate in vitro by antigen-pulsed peritoneal exudate cells (PECs) derived from either strain 2 or strain 13 donors. In this communication, we show that the population of primed F1 T lymphocytes which can be activated by antigen-pulsed strain 2 PECs is largely independent of the population of cells that can be activated by antigen-pulsed strain 13 PECs. This was demonstrated by both positive and negative selection procedures. In the former, T lymphocytes from OVA-primed (2 x 13)F1 donors were enriched by initial culture with OVA-pulsed strain 2 or strain 13 PECs for 1 wk. Cells selected by culture with OVA-pulsed strain 2 PECs responded well to OVA-pulsed strain 2 PECs and poorly to OVA-pulsed strain 13 PECs. If positive selection had been carried out with OVA-pulsed strain 13 PECs, the selected F1 T cells responded well to OVA-pulsed 13 PECs and poorly to OVA-pulsed 2 PECs. Negative selection was achieved by short term culture with antigen-pulsed PECs and by eliminating proliferating cells by treatment with bromodeoxyuridine and light. This procedure demonstrated that the population of primed F1 T lymphocytes which are responsive to OVA or to purified protein derivative of tuberculin can be divided into subpopulations uniquely responsive to antigen on either strain 2 or strain 13 PECs. Evidence was presented to indicate that this selective responsiveness was not the result of the action of alloantigen-specific suppressor cells. The results are considered in terms of current concepts of the genetic and molecular regulation of the interaction of PECs and T lymphocytes. | US |
Virus-immune cytotoxic T cells can inhibit effectively growth of vaccinia virus in acutely infected target cells in vitro by destroying infected target cells before infectious virus progeny is assembled. Together with the fact that virus-specific T cells are demonstrable after 3 days, very early during infection, and with strong circumstantial evidence from adoptive transfer models in vivo, these data suggest that in some virus infections T cells may in fact act cytolytically in vivo to prevent virus growth and spread and be an important early antiviral effector mechanism. | US |
BALB/c T cells, which can prevent normal C57BL IgG2a allotype (G2) production of Ig-congenic partner mice (C.B mice), are shown capable of preventing the growth and G2 production of a C.B plasmacytoma (CBPC 101). Such cytotoxic or suppressor T cells are clearly allotype-specific (G2 Tcs cells). And since CBPC 101 B cells do not require specific helper T cells in order to grow, we infer that G2-bearing B cells (normal or neoplastic) must be the direct target of G2 Tcs cells. This mode of T cell prevention of allotype production contrasts that reported for suppressor T cells in (BALB/c x SJL)F1 mice. | US |
Antibodies in the sera of patients with systemic lupus erythematosus reacted with a nuclear acidic protein called Sm antigen, and these antibodies were used as reagents to identify Sm antigen in preparative fractionation procedures. DNA affinity chromatography showed that Sm antigen was associated with nuclear protein fractions which had DNA-binding capacity. Evidence was also presented that Sm antigen showed preferential binding for single-strand DNA over double-strand DNA. These studies demonstrate that spontaneously occurring anti-nuclear antibodies in disease states may be used to study the properties of cellular proteins which are present in trace amounts. | US |
The synthesis of intracellular J chains was found to be closely associated with that of intracellular immunoglobulin, regardless of its class, during the process of B-cell differentiation. This parallelism between the synthesis of J chain and immunoglobulin was particularly evident in their coincident appearance in serial observations of pokeweed mitogen (PWM)-stimulated lymphocytes. The intensity of J-chain staining by fluorescent reagents in the stimulated cells synthesizing IgG was similar to that found in cells synthesizing IgA or IgM. Evidence was obtained that the presence of J chain in the IgG-producing cells did not reflect antecedent synthesis of IgA or IgM. T cells stimulated by phytohemagglutinin and PWM failed to show J-chain synthesis. Observations on lymphoid cell lines showed a similar parallelism between intracellular Ig and J-chain synthesis; no relation to surface Ig was found. | US |
The genetic control of the immune response of inbred strains of mice to certain antigens has been demonstrated to be governed by a set of Ir genes linked to the major histocompatibility complex (H-2) of mice (1,2). Until recently, the control was thought to be governed by single, dominant genes, located within the I region of the H-2 complex. Merryman et al. (3) originally demonstrated that the immune response to the synthetic terpolymer L-glutamic acid, L-lysine, L-phenylaline (GLphi) is under dominant, H-2-linked Ir gene control (4-7). This was shown both by crossing two nonresponder parental strains to produce responder offspring in the F(1) generation, and by the analysis of appropriate recombinant stains of mice. The two complementing genes have been mapped in the IA and IC regions of the H-2 complex, and have been termed beta and alpha, respectively (5,6). Thus, any strain of mouse may contain neither, one, or both genes. Only mice containing both genes are capable of responding to GLphi. It has been shown using F(1) hybrid and recombinant strains of mice, that the alpha- and beta-genes can complement each other in either the cis (on the same chromosome) or in the trans (on different chromosomes) position (8). In this paper we report the results of studies aimed at answering the question of whether or not the alpha- and beta- genes can complement each other when they are present in different lymphoid cells. To this end we have constructed allophenic mice composed of two nonresponder strains (A and C57BL/6), which show gene complementation in the F(1) generation. Allophenic mice are chimeras containing two cell types coexisting in a "normal" environment. The mice were tested for the specific cellular composition of the two parental cell types and were found to possess a complete range in the relative proportion of the two cell types. This report demonstrates that regardless of the mixture of cell types present in the allophenic mice, none of them were responders to GLphi. Thus no complementation of the alpha- and beta-genes is seen when the two genes are present in different cells. | US |
The sera of three patients with malignant melanoma showing reactivity with surface antigens of cultured autologous melanoma cells were analyzed by mixed hemadsorption and immune adherence assays in conjunction with absorption tests. In contrast to the melanoma-specific antigens demonstrated previously, the surface antigens detected by these sera occurred on a broad range of nucleated cells, both normal and malignant, from human, monkey, mouse, and chicken sources. Each serum had a characteristic pattern of reactivity in absorption tests, indicating the detection of distinct antigenic systems. Two sera showed auto-, allo-, and xenoreactivity, as well as the capacity to distinguish different cell populations in the same individual. The other serum reacted with an antigen apparently universally present on nucleated cells from a variety of species, but absent on erythrocytes. As these patients had been treated with chemotherapy, this may have played a role in the emergence of these broadly reactive autoantibodies. | US |
Cytotoxic T cells specific for Sendai virus were generated by culturing murine spleen cells in vitro together with UV-inactivated Sendai virus. In vivo immunization of donor mice with UV-inactivated Sendai virus resulted in an in vitro secondary response of increased magnitude. Cytotoxic activity was demonstrated in a short-term 51Cr-release assay, using syngeneic tumor cells which had been coated with inactivated Sendai virus by incubation at 4 degrees C for 30 min. The lysis of Sendai virus-coated target cells was restricted by the H-2 haplotype of the target cells, suggesting that the H-2 genes of the target cell contributed to the specificity of the lysis. Kinetic experiments showed that susceptibility to lysis by cytotoxic T cells specific for Sendai virus appeared within 30 min after coating target cells with inactivated virus. Furthermore, there was no detectable synthesis of new proteins in cells treated with UV-inactivated Sendai virus. For these reasons, we suggest that neither viral replication nor the synthesis of new proteins are necessary for the production of the antigen recognized by cytotoxic cells specific for Sendai virus. We infer that the virus-specific component on the target cells is probably a preformed virion antigen adsorbed onto or integrated into the cell membrane. These results imply that, if the cytotoxic T cell recognizes a single antigenic determinant specified both by viral and H-2 genes, this determinant is formed by the physical association of H-2 and Sendai virus antigens rather than by their alteration during the processes of synthesis. | US |
Several recent experiments demonstrate the presence of an essential negatively charged acid group within sodium channels. Sodium permeability titrates away at low pH as if controlled by an acid with a voltage-dependent apparent pKa in the range between 5 and 6. The alkali ion permeability sequence of the channel is best explained by interactions between the cations and a strong negative charge in the channel. Block of sodium currents by a variety of metal and organic cations again points to a cation-coordinating site in the channel. The "blocking cations" and protons also oppose the bindings of tetrodotoxin and saxitoxin. The negative charge in the channel seems to be essential in selecting appropriate cations and in lowering their activation energy for permeation. The same charge seems to form part of the toxin receptor. At present this charged group is the chemical group known to be associated with sodium channels.--Hille B. An essential ionized acid group in sodium channels. | US |
A technique has been developed for the separation of proteins by two-dimensional polyacrylamide gel electrophoresis. Due to its resolution and sensitivity, this technique is a powerful tool for the analysis and detection of proteins from complex biological sources. Proteins are separated according to isoelectric point by isoelectric focusing in the first dimension, and according to molecular weight by sodium dodecyl sulfate electrophoresis in the second dimension. Since these two parameters are unrelated, it is possible to obtain an almost uniform distribution of protein spots across a two-diminsional gel. This technique has resolved 1100 different components from Escherichia coli and should be capable of resolving a maximum of 5000 proteins. A protein containing as little as one disintegration per min of either 14C or 35S can be detected by autoradiography. A protein which constitutes 10 minus 4 to 10 minus 5% of the total protein can be detected and quantified by autoradiography. The reproducibility of the separation is sufficient to permit each spot on one separation to be matched with a spot on a different separation. This technique provides a method for estimation (at the described sensitivities) of the number of proteins made by any biological system. This system can resolve proteins differing in a single charge and consequently can be used in the analysis of in vivo modifications resulting in a change in charge. Proteins whose charge is changed by missense mutations can be identified. A detailed description of the methods as well as the characteristics of this system are presented. | US |
The placental diffusing capacity for carbon monoxide was measured in unanaesthetized monkeys (M. Mulatta). Maternal and fetal blood was sampled from chronically placed catheters while the mother breathed 50 or 100 parts per million of CO. Diffusing was calculated from the amount of CO taken up by the fetus divided by the partial pressure difference across the placenta, it averaged 0.646 plus or minus 0.062 (SEM) ml x min(-1) x torr(-1) x kg(-1) of fetal weight. The significance of this index of respiratory gas exchange in the monkey placenta is discussed with respect to previous measurements in other species and with respect to fetal growth. | US |
Adult cats survived left lateral funiculotomy 1 to 153 days. The pericruciate cortex was studied electron microscopically in these as well as sham-operated and unoperated animals. Ten days after surgery Betz cells of the right pericruciate cortex displayed disaggregation of cytoplasmic ribosomes; random dispersal and degranulation of the normally compact arrays of cisterns of rough ER; in some cells perinuclear and peripheral disposition of remaining Nissl bodies; retispersion of the Golgi apparatus; and, uncommonly, neurofilamentous hyperplasia. Fourteen days postoperatively cytoplasmic ribosomes were largely regrouped in rosette arrangements and Golgi membranes were evenly distributed in the cytoplasm. Further reversion of the ER toward a normal appearance occurred 28 days postoperatively but substantial perikaryal atrophy had supervened in many neurons by 49-153 days after surgery. Evidence of nerve cell death was not found. Concentric membranous arrays derived from ER and associated with autophagic bodies and mitochondria were identified in dendrites of normals and cats that had been operated upon, perhaps more frequently contralateral to the spinal operation. Electron-dense and electron-lucent degenerative changes in dendrites also occurred, especially early after operation. Degenerating myelin sheaths were detected in the pericruciate cortex of animals that had been operated upon and sometimes were captured in the process of phagocytosis by oligodendrocytes as well as astrocytes and microglia. The long-term persistence of axotomized Betz cells, albeit in an atrophic state, and the reversibility of some of the cytologic responses to axon injury suggest that these neurons may retain a capacity for axon regeneration that could be mobilized, as by pharmacologic means. | US |
Hepatic glycogen content, blood glucose and lactate concentrations, and hepatic mitochondrial energy-linked functions were measured in rats in late hemorrhagic shock. As judged by correlation coefficients, the following significant relationships were noted: (formula: see text). Glycogen depletion, hypoglycemia, and lactic acidemia occurred frequently. However, alone or in combination, these variables did not relate significantly to need for or amount of shed blood uptake prior to sacrifice. Neither hepatic glycogen depletion nor uncoupled hepatic mitochondrial oxidative phosphorylation alone accounted for hypoglycemia. The genesis of hypoglycemia was determined by the occurrence of both these events in either sequence. When hepatic mitochondrial oxidative phosphorylation became uncoupled, the blood glucose concentration and hepatic glycogen content were linearly related (r = 0.94). This effect probably results from impaired gluconeogenesis due to mitochondrial dysfunction. | US |
Improved surgical techniques and judicial use of available antibiotics have reduced the number of postoperative complications over the past decade. However, septic and hemorrhagic shock occur all too frequently, and each carries with it an appreciable morbidity and mortality. Endotoxins and hemorrhage are both known to suppress the phagocytic activity of the reticuloendothelial system (RES). On the other hand, zymosan, a yeast (Saccharomyces cerevisiae) cell wall preparation administered intravenously, results in temporary RES hyperplasia and increased phagocytic activity. Dogs were pretreated with zymosan to determine the degree of RES stimulation and protection against endotoxin and hemorrhagic shock attainable. Twenty-five dogs received intravenous zymosan (10 mg/kg) on days 1, 2, and 3. Another 24 dogs served as controls. On day four, one-half the animals in each group received E coli endotoxin (1.5 mg/kg) intravenously. The other animals underwent two hours of hemorrhagic shock at a mean blood pressure of 40 mm Hg. Seventy-two hour survival was as follows: Endotoxin treated, 66.7% (8/12); endotoxin control, 27% (3/11); hemorrhagic treated, 53.3% (8/15); and hemorrhagic control, 28.6% (4/14). Hemodynamic, metabolic, and lysosomal enzyme parameters were evaluated. No zymosan toxicity was observed. These findings suggest that an RES stimulant such as zymosan could be incorporated as preoperative adjunctive therapy to induce resistance to these shock syndromes in the elective surgical patient. | US |
The present study evaluated the effects of indomethacin (INDO) on cardiovascular and lysosomal mechanisms during experimental myocardial ischemia (MI). INDO (5 mg/kg) was infused IV prior to MI, and the results were compared to vehicle-treated and sham-operated dogs. INDO induced a slight hypertension after MI. Additionally, INDO attenuated the decline in coronary blood flow in the non-ischemic myocardium after MI. Myocardial lysosomes (biopsied three hours post-MI) were more labile in ischemic than in nonischemic tissue, and INDO had a stabilizing effect on lysosomes from ischemic tissue. Plasma activity of cathepsin was increased following MI, and INDO attenuated this increase. In the myocardium (biopsies three hours post-MI) prostaglandin A + E levels were suppressed 60% in both ischemic and nonischemic tissue with INDO treatment; prostaglandin F2 alpha levels were lower with INDO treatment but not significantly so. These results suggest that INDO has a stabilizing effect on lysosomes in vivo, possibly involving an endogenous prostaglandin mechanism, and this protective effect may attenuate lysosomal damage to the cardiovascular system during MI. | US |
One hundred-twenty Sprague-Dawley rats were shocked at 60 torr for 60 minutes and at the end of this period shed blood was reinfused. The animals were divided into three groups at random. These groups were either treated by N saline or glucose in N saline or glucagon in N saline. Glucagon treatment resulted in increased liver and muscle glucose-glycogen stores in the late period following shock. This was associated with a decrease in liver pyruvate and lactate and improved survival. It appears that glucagon more favorably affects the response to shock in this model than does treatment with glucose or saline. | US |
Nine dogs and one primate were placed on total cardiopulmonary bypass and subjected to a simulated hemorrhagic shock procedure. Venous compliance was determined by occluding the venous outflow catheters; venous flow and pressure drop were used to calculate resistance. Individual measurements were made for the superior (SVC) and inferior vena caval (IVC) beds. During hypotension, compliance increased equally in the SVC and IVC; following reinfusion, IVC compliance was consistently lower than SVC compliance. Resistance of the sVC system increased slightly more rapidly during early hypotension than did that of the IVC, but SVC resistance then decreased and remained significantly below that of the IVC system throughout the posthypotension period. These results are interpreted as indicating a different response of the two vascular beds, particularly an increase in IVC arteriolar resistance with a decrease in venous tone. To the extent that the splanchnic bed contributes to the IVC system changes, they are contrary to the concept of a maintained venous tone and decreased arteriolar tone after hemorrhagic shock. | US |
Exocrine pancreatic tissue from 65 male Sprague-Dawley rats was studied by light and electron microscopy to determine if acute lethal and sublethal alterations seen in the human exocrine pancreas following shock could be duplicated in an animal model. Two models were used: one in which 50% of the blood was withdrawn via cardiac puncture with no reinfusion and another in which the animal was subjected to a hypovolemic episode (40 mm Hg) for 60 minutes, with reinfusion of the blood. Animals were killed at various intervals, and pancreatic tissue was sampled for morphological study. No differences were seen between experimental and control animals by light microscopy. The main subcellular alteration seen using these models was the formation of numerous autophagic vacuoles. From these studies it appears that the alterations seen in the human pancreas in shock can be duplicated in the rat and that a shock model that involves removal of more than 50% of the animal's blood volume is necessary to cause irreversible cell damage to the exocrine pancreas. | US |
During hemorrhagic shock, increased uptake of NH3 from the gut with inadequate compensation by the liver results in hyperammonemia. The effect on brain metabolism of acute hyperammonemia alone, as compared with normocapnic hypoxia, was investigated in 11 pentobarbital anesthetized (30 mg/kg) dogs. These animals were paralyzed (pancuronium bromide) and artificially ventilated to maintain the end-tidal fraction of FETCO2) CO2 constant. Arterial blood and cerebrospinal fluid (CSF) samples were obtained following control, 30-minute hypoxia, 60-minute NH3 infusion, and 30-minute hypoxia combined with NH3 infusion. These were analyzed for PaO2, PCO2, pH, and NH3. CSF samples were further analyzed for glutamine, urea, lactate, pyruvate, and citrate. There were no significant changes in urea or citrate. Glutamine, lactate, and the lactate/pyruvate ratio were significantly elevated by hypoxia and by NH3 infusion. (formula: see text). Thus, an acute NH3 load is capable of disrupting aerobic glycolytic metabolism. Hence, hyperammonemia may affect brain function during shock. | US |
The triad of gastric mucosal ischemia and lumenal acid and bile is known to be ulcerogenic. However, the explanation for progressive mucosal injury after resuscitation from hemorrhagic shock is not known, because ischemia does not persist. To test the hypothesis that persistent pathophysiologic arteriovenous shunting is the cause of progressive mucosal injury after shock, we studied in vivo canine gastric mucosal oxygenation and transmembrane potential difference during and after one hour of hemorrhagic shock with and without topical acid (160 mM HCl) and taurocholate (1 mM) in the mucosal bathing solution. Although systemic blood pressure and total gastric blood flow returned to normal after shock in all groups, only the group with topical acid and taurocholate developed mucosal erosions and had persistent hypoxia and inhibition of potential difference in surface epithelial cells. We conclude that pathophysiologic arteriovenous shunting persists in the superficial part of the gastric mucosa after shock. It is tempting to speculate that shunting may replace ischemia in the ulcerogenic triad during the postresuscitation phase of injury. | US |
Terms such as "insulin resistance" and "glucose intolerance" applied to shock-induced hyperglycemia suggest that this state may prejudice survival. However, our data indicate that posthemorrhage hyperglycemia improves short-term survival. Rabbits, either fed until the experiment or fasted for 24 hours, were shocked by rapid removal of 25% of their blood volume (BV) measured by 131IHSA. During the next 60 minutes, blood pressure (BP) was recorded, and the following variables were measured every 10 minutes: plasma volume (PV); arterial and venous plasma osmolality (PO), glucose, lactate, Na, K and hematocrit. Other fasted animals studied similarly received short intravenous pulses of hypertonic xylose after bleeding. The PO of fed animals, who all survived for 60 minutes rose to an extent accounted for by rises in glucose and lactate. A significant PV fluid gain was maintained for 60 minutes. The fasted animals, 42% of whom died before 60 minutes, had a flat glucose curve with a correspondingly small rise in PO. The PV fluid balance, after an initial small gain, became negative. Although a lower blood pressure in fasted rabbits was probably due to lack of PV refill, death resulted from hyperkalemia. Poor tolerance of fasted animals to shock is not attributable only to less glucose for energy metabolism, because when they received xylose, homeostatic features of fed animals were restored. The data suggest that, immediately after hemorrhage, glucose acts as a nonpermeant solute drawing fluid into the circulation. This study also shows that control of the nutritional status of animals used for shock models is important. | US |
In acute renal failure in man following shock and trauma, an amazing discrepancy was found between the complete breakdown of renal function and the very modest histological and ultrastructural changes in "immediate autopsy" patients, even in those who sustained septic shock. Although, from this limited number of studies no satisfactory interpretation of the pathogenesis of acute renal failure can be deduced from the structural changes found, the findings do indicate that hypoxia plays a key role in aggravating the structural changes that induce permanent cell damage in man following shock of various etiologies including septic shock. | US |
Type II alveolar cells can be isolated and partially purified from adult rat lung by a series of steps that includes enzymatic digestion of the lung with trypsin and separation of cells on a discontinuous albumin density gradient. The yield of the isolated type II cells depends on the supplier and the housing of the rats used to prepare the cells. With specific pathogen-free rats housed in a laminar flow hood, the yield was 20.3 x 10(6) cells per rat, of which 50 per cent were type II cells. With rats from 2 other suppliers and no special housing, the yields were 8.8 and 8.3 x 10(6) cells per rat, of which 67 and 65 per cent were type II cells. The ultrastructural appearance of the isolated cells was similar to that of cells from intact lung, except for some dilatation of the endoplasmic reticulum and the perinuclear space. Most cells (92 +/- 5 per cent) excluded the vital dye, trypan blue. The cells consumed O2 at the rate of 76 +/- 12 nmole per 10(6) cells per hour and released only 5.7 +/- 2.0 per cent of their lactate dehydrogenase, a cytoplasmic enzyme, into the medium after 1 hour of incubation. The isolated type II cells contained disaturated phosphatidylcholine, a major component of purified surface-active material. The cells, however, had a low glucose utilization compared to their O2 consumption, which may indicate an abnormality in the metabolism of glucose. This population of cells could be further purified to 89 per cent type II cells by unit gravity velocity sedimentation. | US |
Superoxide (O2-.) is a highly toxic free radical that may be an important component of pulmonary O2 toxicity. The primary defense against this free radical is superoxide dismutase. Rats were exposed to aerosolized superoxide dismutase, and it failed to modify either the time course or the cumulative toxicity of 100 per cent O2. Because the aerosolized enzyme can be expected to be delivered only to the extracellular space of the lung, it is suggested that the primary site of production and of damage due to O2-induced free radicals must be within the intracellular space. | US |
A 34-year-old alcoholic and drug addict developed cavitary pulmonary sporotrichosis that progressed slowly during 6 years. Pulmonary resection and pre- and postoperative therapy with amphotericin B were associated with prompt clinical improvement with no evidence of relapse during a 2-year follow-up. Histologic examination of lung revealed granulomatous inflammation with organisms consistent with Sporothrix schenckii, and interstitial talc (magnesium silicate) granulomas. The latter finding was consistent with the history of intravenous drug abuse. Although the presence of silicates in lung enhances the pathogenicity of some microorganisms, the relation of these findings to the pathogenesis of sporotrichosis in our patient is unclear. | US |
Beclomethasone dipropionate (200 micrograms, administered by inhalation to conscious sheep, does not affect tracheal mucous velocity during a 60-min period. | US |
A survey of 300 grain elevator workers revealed that 77 per cent complained of eye symptoms; 64 per cent, of nasal symptoms; and 88 per cent, of one or more respiratory symptoms on exposure to airborne grain dust. Symptoms on exposure were independent of age and length of employment. Cough and wheezing on exposure were more common among smokers than nonsmokers (P less than 0.025). Nineteen per cent of the workers had had episodes of grain fever. The prevalence of chronic bronchitis was 37 per cent (42 per cent of smokers and 30 per cent of nonsmokers). Wheezes on auscultation were found in 23 per cent. Measurements of lung ventilatory function, as well as diffusing capacity, correlated significantly with age and smoking habits, but not with length of employment. Thirty-seven per cent of the workers had an abnormal mean forced expiratory flow during the middle half of the forced vital capacity (47 per cent of smokers and 13 per cent of nonsmokers), and 34 per cent had an abnormal maximal expiratory flow after exhalation of 50 per cent of the forced vital capacity (40 per cent of smokers and 13 per cent of nonsmokers), whereas only 13 per cent had an abnormal ratio of 1-sec forced expiratory volume to forced vital capacity. There was no correlation between precipitins to fungi, bacteria, grain, or grain dust antigens and acute or chronic respiratory symptoms, lung function, or grain fever. There was, however, a significant correlation between cutaneous reactivity to grain dust and wheezing on exposure (P less than 0.02). Abnormal flows at low lung volumes were more common among cutaneous reactors to common allergens. We concluded that exposure to airborne grain dust can cause acute inflammatory reaction to the exposed mucosa, and it is highly probable that grain dust contributes and, in some cases, causes chronic airway disease. | US |
Immunologic stimuli to the airway of rhesus monkeys were given by aerosol challenge with ascaris antigen or anti-IgE. Both of these stimuli produce immediate-type airway responses. When 2 sequential aerosol challenges were given during the same experiment, the response following the second stimulus was always less than or equal to the first response following any combination of stimuli except the anti-IgE-ascaris sequence. The second response following the latter challenge was always greater than or equal to the first response. The possibility that this exception was the result of anti-IgE priming mediator releasing cells for antigen was not supported by in vitro experiments. It is suggested that the results obtained with the anti-IgE-ascaris sequence may relate to the presence of intralumenal mast cells in the bronchi and the molecular weights of the 2 immunologic stimuli. | US |
The bioavailability of theophylline from single doses of an elixir (Elixophyllin) and two different tablet formulations, as compared to intravenous aminophylline, was studied with a crossover design in 12 normal volunteers. Both tablet formulations (Marax and Tedral) contain ephedrine. Marax contains hydroxyzine hydrochloride, and Tedral contains phenobarbital. The absorption of theophylline was most rapid from the elixir, whereas that from Marax was faster than that from Tedral. The peak concentrations of theophylline after administration of the 3 oral dosage forms were in the order, elixir greater than Marax greater than Tedral, however, the time to achieve peak concentration was highly variable and did not differ significantly among the 3 products. On the basis of area under the serum concentration-time curves, the absorption of theophylline from the elixir and from Marax was essentially complete. The area under the serum concentration curve after administration of Tedral was significantly less than that after intravenous aminophylline, elixir, and Marax; however, when the individual areas under the concentration curves were adjusted for intrasubject variation in elimination rate constant, the mean area under the concentration curve after Tedral no longer differed significantly from those of the intravenous and other two oral products. A large degree of intersubject variation in the oral absorption of theophylline was observe din this study. Therefore, in addition to the well-documented, large individual variation in the serum clearance of theophylline, intersubject differences in the absorption of the drug is another factor that complicates proper adjustment of the dose in oral theophylline therapy. | US |
Using beagle dogs, we have developed an animal model for the evaluation of the effect of chronic cigarette smoking on pulmonary defense and function and on lung structure. The smoking apparatus developed allows the dog actively to inhale properly diluted (1:4) smoke directly from the cigarette through a mouthpipe. In this model, 6-month and 1-year periods of mild to moderate smoking caused impairment of tracheal mucociliary transport and bacteriosuppressive activity of alveolar macrophages, with little change in pulmonary function. Morphologically, subtle, but significant, lesions were noted in the central airways and bronchiolar walls, consisting of tracheal epithelial basal cell hyperplasia, proliferation of goblet cells in central airways, and peribronchiolar infiltration by inflammatory cells. Morphometry of bronchiolar size distribution, volume proportion of parenchymal structure, and alveolar surface area, however, failed to show significant differences between the groups. | US |
Alveolar wall from the lung of aging humans shows a progressive decrease in maximal extensibility, which should follow an increase in resting tissue length rather than a reduction in maximal length. An increase in resting tissue length is compatible with the change in lung volumes and reduction in elastic recoil that occurs with time. A model of the lung was used to compare the effects of a change in resting tissue length in diminishing elastic recoil with that of a reduction in the volume density of the elastic elements (emphysema). Such differentiation is important in selecting an animal that may model the aging or emphysematous lung. In the rat, rabbit, and horse, alveolar walls show no decrease in maximal extensibility with age. In the male monkey (M. nemestrina and M. mulatta) between birth and 2.4 years there is a decrease in maximal extensibility that lacks significance for the limited age span examined. On the other hand, the energy loss in length-tension cycling (hysteresis) of alveolar wall increases in aging humans, diminishes in rats and rabbits, and shows little change in horses and monkeys. The breaking force of alveolar wall increases with age in rats and rabbits but does not change significantly in the other species. Of these species, the monkey promises a better model of the age-related changes in maximal extensibility of alveolar wall. A measure of maximal extensibility can distinguish the effects of dilatation of air spaces from those of destruction of alveolar wall in causing loss of lung elastic recoil. | US |
Twenty patients with pulmonary nodules consisting of concentric hyaline lamellae, usually accompanied by perivascular collections of plasma cells and lymphocytes, were studied. In most instances, the lesions were multiple, bilateral, and mildly symptomatic. Many of these nodules showed all of the staining characteristics of amyloid, but others had an atypical birefringence pattern. No infectious agents were identified, and no consistent pattern of dysproteinemia was observed. Two of the patients had prior histories of tuberculosis. In other cases, the nodules were of unknown origin and pathogenesis. Four cases were complicated by sclerosing mediastinitis, and one, by retroperitoneal fibrosis and amyloidosis. Our current working hypothesis is that these lesions represent an exaggerated and, possibly, continuing immune response, perhaps to one of a number of agents. | US |
The purpose of this presentation is to summarize briefly the evidence, much of it recent and direct, that the most prominent lesion components of the advanced atherosclerotic plaques in experimental animals, namely the necrotic center and the intracellular lipid, can undergo substantial regression. Some of the data will be reviewed indicating that this improvement of lesions in size, consistency and safety is due to a combination of remodeling, regression and healing. The recent evidence will be included indicating that human lesions can also respond favorably to the same rigorous serum cholesterol lowering regimens that lead to improvement of the advanced monkey and swine plaques. | US |
The purpose of this paper is to present a brief coordinated overview of the recent results of research at the artery cell level which appear to have the greatest impact on the rapidly improving understanding of the pathogenesis of atherosclerosis in humans. The majority of these studies have employed in vitro methods and utilized the tools of modern cellular and molecular biology. These include microdissection; cell separation; tissue or cell culture; enzyme, lipid and protein chemistry as well as immunochemistry, ultrastructural visualization, cell organelle and membrane fractionation and the use of genetic markers. With these tools it is possible to study the interaction of the major space-occupying cells of the atherosclerotic plaque (especially the arterial smooth muscle cells) with many of the blood components, especially the lipoproteins and the other serum factors that appear to influence cell division. This direction of study appears to usher in a new era of atherosclerosis research. | US |
We carefully selected 30 men with primary gout, rendered asymptomatic by therapy, to examine the frequency and type of hyperlipidemia and hyperlipoproteinemia, with the objective of determining whether serum uric acid, alcohol intake, liver function, kidney function, and (or) drugs were participating in the secondary lipid disorder. Sixty-one age- and sex-matched men were used as controls. About 73% of the gout patients had hypertriglyceridemia, 1.6-fold the frequency found in the control group. Types IV and IIb lipoprotein electrophoretic patterns were most prevalent in the gout group. Neither alcohol intake nor hyperuricemia, per se, seems to be the cause of the lipid and lipoprotein disorder and cannot be related to liver or kidney dysfunctions. Obesity was the major underlying factor associated with the lipidemia. The study suggests that diet and, possibly, defective clearance of triglycerides may be etiologic factors associated with the abnormal serum triacylglycerol (triglyceride) and lipoprotein concentrations in these individuals. | US |
We describe a rapid, sensitive, and specific "high performance" liquid chromatographic analysis for disopyramide and its mono-N-dealkylated metabolite in serum, urine, and saliva. We used a mu-Bondapak CN column and an acetate buffer mobile phase containing methanol. Retention times for the two compounds and the internal standard, p-chlorodisopyramide, were 3.4, 4.1, and 6.3 min, respectively. The lower limits of sensitivity for drug and metabolite were 50 and 80 micrograms/L, respectively, with maximum coefficients of variation of 4.6 and 12%, respectively. Currently used antiarrhythmic drugs did not interfere with the analysis of disopyramide, and the pharmacokinetics of the drug, obtained from studies of one subject, agree well with reported values. | US |