bluuebunny/crossref_metadata_2025 huggingface dataset:
Renal clearance of glucose in hypothermic dogs
Authors: Kanter G. S.
Published: December 2017

Quantitative alterations in both glomerular filtration (GFR) and tubular reabsorption of glucose, before, during and after onset of hypothermia were investigated. Urine was collected by direct cannulation of ureters and arterial blood obtained from a femoral cannula. Creatinine was used to measure GFR and glucose was analyzed by the glucose-oxidase method. During control period (rectal temp. 38°C) it was found that onlg a trace (17 ± 4 mg %) (.09 ± .02 mg/min.) of glucose spilled over into the urine. With the development of hypothermia a progressive fall in glomerular filtration rate was observed (78 ± 5 ml/min. at control rectal temp. (R.T.) to 30 ± 5 ml/min. at R.T. of 25°C). In spite of the fact that less fluid was filtered across the glomerulus, both urine volume and glucose excretion increased markedly (373 ± 122 mg %) (4.3 ± 1.9 mg/min.) at R.T. of 25°C. There is obviously a twofold effect of hypothermia on renal function, physically via the cardiovascular system resulting in a falling GFR and chemically on the tubular reabsorptive processes resulting in a decreased glucose reabsorption. To study the kinetics of this decreased glucose reabsorption, glucose Tm was investigated. It was found that control glucose Tm averaged 380 mg/min. (the E/F ratio being 52%). At 27°C R.T. the Tm was 103 mg/min. (E/F ratio being 73%).
Effect of single and chronic choline supplements on phospholipid metabolism of the dog
Authors: Di Luzio N. R. , Zilversmit D. B.
Published: December 2017

The administration of a single dose of oral choline to choline-deficient dogs results in an increased synthesis of phospholipids of liver, but not of kidney, small intestine, muscle, skin and aorta. The rate of incorporation of P32 into liver phosphatide is greater in choline-deficient dogs than in normal dogs or in animals receiving daily choline supplements. No simple relation between rate of lipid phosphorylation and lipotropic action of choline could be demonstrated.
Effect of adrenalectomy and cortisone on peripheral nerve function
Authors: Wright Ernest B. , Lester E. Jean
Published: December 2017

Fifty-four male Holtzman strain rats, 200–250 gm, were subjected to the same surgical treatment; 27 adrenalectomized, the others sham-operated. Fifteen of each group were kept on normal diet; four on 0.9% NaCl drinking water; four given daily injections of 1 mg cortone acetate and four, 2 mg cortone acetate. The excitability constant k (H. A. Blair. J. Gen. Physiol. 15: 709, 1932) was 30% lower in adrenalectomized rat nerve than in normal and the velocity of conduction was slightly decreased. The effect of adrenalectomy on excitability and conduction was reversed or prevented by 1 mg cortone acetate or by 0.9% NaCl drinking water. Two milligrams cortone acetate in normal animals also reduced k slightly but did not affect the velocity. The survival time of adrenalectomized rat nerve deprived of oxygen was decreased 12% from normal. Administration of cortisone to normal animals also resulted in a slightly decreased survival time. The oxygen uptake rate was 214 cu mm/gm/hr. in nerves from adrenalectomized rats; 181 cu mm/gm/hr. in normal rat nerves, an increase of 18%. Immersion of normal rat nerves in low-sodium solution (less than 10% of normal) produced excitability changes similar to the adrenalectomy effects. It is concluded that the effect of adrenalectomy on excitability of peripheral nerve is due to the resultant change in electrolyte balance, especially with respect to the Na ion and an apparent contradiction between results obtained from brain tissue and nerve tissue by previous investigators has been resolved.
Distribution of acid-soluble nucleotides in hind leg muscles of mice with ‘dystrophia muscularis’
Authors: Zymaris Michael C. , Epstein Nathan , Saifer Abraham , Aronson Stanley M. , Volk Bruno W.
Published: December 2017

Qualitative and quantitative distribution of acid-soluble nucleotides in muscle from mice with dystrophia muscularis was compared to normal mouse muscle using filter paper chromatography followed by elution and U.V. spectrophotometry. Qualitatively, no apparent differences were found in the number and types of nucleotides present in both tissues. Similar results were obtained using radioautography with P32. Significant amounts of AMP, ADP, ATP, DPN, GTP, GDP were found, while smaller amounts of components tentatively identified as UDP, UTP, CTP and IDP were also observed. The concentrations of AMP, GTP (including UTP), and GDP (including UDP, CTP, and IDP) were significantly higher in the hind limb muscles of dystrophic mice than those obtained for normal mouse muscles, while for ATP the reverse was found. Slight or no significant differences were found in the acid-soluble nucleotides of animals with experimentally induced atrophy of the hind leg when compared to the normal group, while histologically there was a significant decrease of the individual muscle fiber diameter in the atrophic muscle.
Factors modifying water metabolism in rats fed dry diets
Authors: Radford Edward P.
Published: December 2017

To determine dietary factors which govern water turnover in rats, water intake and output were studied during 24-hour intervals. Rats given water ad libitum and Purina laboratory chow or a synthetic diet voluntarily maintained an antidiuretic state, restricting water intake and excreting urine of nearly maximum concentration. Dietary modifications which have been studied include: addition of large amounts of NaCl or urea; a protein-free diet with or without urea added; and diets containing various levels of Na, K and Cl. Conclusions drawn from these studies are as follows: under most conditions water intake was determined by the minimum urine water for solute excretion or by changes in fecal volume; the degree of antidiuresis maintained by the rats may depend on the electrolyte content of the diet. Nitrogen turnover has an additional influence on water metabolism through the effect of urea excretion on the renal concentrating mechanism. Evidence also presented indicates that Pitressin may act to ‘reset’ the threshold of drinking, with a resulting concentration of body fluids.
X. Endogenous dilution of administered labeled acetate during lipogenesis and cholesterogenesis in two types of obese mice
Authors: Zomzely Claire , Mayer Jean
Published: December 2017

Determination of dilution of administered labeled acetate by endogenously produced acetate in two types of obese mice: goldthioglucose obese mice (regulatory obesity) and obese hyperglycemic mice (metabolic obesity) shows that this dilution is of the same order for obese and non-obese mice when fed ‘ad libitum.’ When fasted, dilution is again of the same order for goldthioglucose obese mice and normal controls, but is twice as great for obese hyperglycemic mice. These data in conjunction with results obtained on incorporation of C14 into fatty acids and cholesterol show that the increased synthesis of these lipids is related solely to the hyperphagia in the case of the goldthioglucose obese mice. By contrast, the obese-hyperglycemic mice show rates of fatty acid and cholesterol synthesis which are three times the control levels even when fasted. These results justify the previously drawn distinction between ‘regulatory’ and ‘metabolic’ obesities.
Functional development of the emetic apparatus in the cat
Authors: Brizzee K. R. , Vitale D.
Published: December 2017

A series of cats and kittens varying in body weight from 150 gm (about 2 days of age) to over 3 kg (adult) were tested for the emetic response with graded doses of lanatoside C (.06–.8 mg/kg) and total body x-irradiation (12,000 r). At .06 mg/kg lanatoside C, the incidence of vomiting decreased from 52% in the adult group to zero in the 400-gm animals. At .08 and .12 mg/kg all the adult animals responded, but the incidence dropped to zero in the 250-gm group (about 10 days of age). At .3 and .8 mg/kg the incidence dropped from 100% in adults to zero in the 150-gm group. With total body x-irradiation at a maximum dose of 12,000 r the incidence was 100% in all groups between 400 gm and the adults, dropped to 50% in the 250-gm animals and to zero in the 150-gm group. It is thus clear that the period between the 150-gm and 250-gm stages is the critical period in the development of the emetic mechanism for the two stimuli employed in this study. The very low (about 6%) incidence of retching in animals of the younger groups which did not vomit suggests that the various components of the mechanism mature almost simultaneously.
Metabolic effects of l-thyroxine and l-triiodothyronine on the intact rat and selected excised tissues
Authors: Whaley R. A. , Hart T. M. , Klitgaard H. M.
Published: December 2017

Time-response curves for the oxygen consumption of the intact rat and excised tissues were determined after single equimolar injections of l-thyroxine or l-triiodothyronine. In the whole animal, injection of either material resulted in significant increases in BMR within 12 hours. Thyroxine treatment of the intact rat caused an increased oxygen utilization until the sixth day, while the triiodothyronine-treated group began declining after the 4th day. Tissue oxygen consumption was determined in kidney, liver, heart, gastric mucosa, skeletal muscle, diaphragm and duodenal smooth muscle during the same time periods as used in the study of the whole animal. The oxygen consumption of all tissues except smooth muscle showed a significant increase above the control value. The earliest response to either hormone occurred 12 hours after injection in liver, kidney and cardiac muscle and all reactive tissues reached their maximal values in 3 days with the exception of skeletal muscle. All tissues from thyroxine-injected animals maintained a near maximum oxygen consumption through the 9th day except for cardiac muscle; all tissues from triiodothyronine-injected animals (except skeletal muscle) showed significant decreases by the 7th day.
Analysis of Vagal and Cholinesterase Effects on the Heart of Chelydra serpentina
Authors: Yonce Lloyd R. , Brassfield Charles R.
Published: December 2017

Page 589: Lloyd R. Yonce and Charles R. Brassfield, "Analysis of vagal and cholinesterase effects on the heart of Chelydra serpentina." Figures 3 and 4 are reversed. The legends are correct.
Effects of pinealectomy and of a bovine pineal extract in rats
Authors: Wurtman Richard Jay , Altschule Mark D. , Holmgren Uno
Published: December 2017

Fifty-four 26-day-old female rats of the CD strain were divided into four groups of 10 or 11 each, i.e. 1) controls; 2) animals given 0.3 ml of a protein-free bovine pineal extract daily intraperitoneally for 28 days; 3) sham-operated animals; 4) pinealectomized animals. In a second experiment two groups of six each were divided into a) control animals given a diet restricted with respect to Na, K and phosphate, and b) animals on the same diet, given 1.0 ml/day of the pineal extract. Pinealectomy caused ovarian hypertrophy ( P < .001), pituitary hypertrophy ( P < .001), and adrenal hypertrophy ( P < .05). The extract reversed these changes. Giving the extract to intact animals caused effects varying with the dose. The dose of 0.3 ml given daily caused gonadal atrophy ( P < .05), pituitary atrophy ( P < .001) and insignificant adrenal activity. The dose of 1.0 ml caused further gonadal atrophy ( P < .001) and significant adrenal atrophy ( P < .05).
Sex and sex-cycle differences in rat serum protein concentrations
Authors: Heim Werner G.
Published: December 2017

The relative concentrations of the various blood serum proteins, and especially of albumin, were found to be significantly different in male and female rats when examined by moving boundary or zone electrophoresis. However, no significant differences were noted in the sera obtained from rats at different points in the estrus cycle.
Carbohydrate metabolism in normal and altitude-exposed mice following arsenite poisoning
Authors: Berry L. Joe , Smythe Dorothy S.
Published: December 2017

The metabolic basis for the greater susceptibility of high altitude-exposed mice to arsenite poisoning was investigated. There was, initially, in altitude-exposed mice less muscle glycogen and blood sugar and these became depleted, along with liver glycogen and total body carbohydrate, more rapidly following intraperitoneal injections of arsenite than in control mice. At a dosage level when altitude-exposed mice were dying in convulsions, normal mice survived with what appeared to be enough carbohydrate to protect them. Livers of altitude-exposed mice retained a significantly larger percentage of isotopically labeled arsenite 1 and 3 hours postintraperitoneal injection than livers of normal mice. The differential effect of arsenite was not accompanied by an unequal accumulation of metabolic intermediates in livers nor by a difference in rate of loss of liver glycogen under in vitro conditions. Impaired synthesis may be more significant than increased loss in explaining these results.
Effects of age, body size and growth hormone on level of tryptophan peroxidase-oxidase in rat liver
Authors: Rivlin Richard S. , Knox W. Eugene
Published: December 2017

The specific activity of rat liver tryptophan peroxidase increased with age, and at 400 days was more than double the level at 38 days of age. The amount of enzyme per 100 gm body weight also increased significantly. This change of enzyme activity with age was attributed to a substrate-induced enzyme adaptation occurring under physiological conditions caused by the tryptophan available for catabolism as growth slowed. Bovine growth hormone injections increased the level of the enzyme in rats.
Estimation of gastric hydrochloric acid secretion in rats by a test meal technique
Authors: Thornton George H. M. , Clifton James A.
Published: December 2017

A test meal containing phenol red and hypertonic sucrose was instilled intragastrically into rats through a rubber catheter. The phenol red was used to calculate the volume of gastric contents and the amount of HCl lost from the stomach and, therefore, the quantity of HCl secreted. The stimulating effect of subcutaneous histamine on gastric HCl secretion was studied. Maximum stimulation occurred with doses of more than 2 mg of histamine phosphate. The duration of the response was 45 minutes. Doses of up to 8 mg of histamine phosphate did not produce toxic effects. A 45-minute test meal, in conjunction with a maximum stimulating dose of histamine, was used to demonstrate inhibition of acid secretion and gastric motility following topical application of p-chloromercuribenzoate to the gastric mucosa.
Relation of metabolic events to gastric contractions in the rat
Authors: Sudsaneh Saovanee , Mayer Jean
Published: December 2017

A water-filled balloon system was used to study gastric hunger contractions in normal rats. Fasted rats have active hunger contractions alternating with periods of quiescence. The contractions occur at a rate of one or two per minute for 10–15 minutes followed by a quiescent period of 5–10 minutes. Exposure to cold (5°C) and heat (32° and 40°C) inhibited gastric hunger contractions in fasted rats. Intravenous administration of 75 µg glucagon or i.v. injection of 50 µg epinephrine and norepinephrine also inhibited gastric hunger contractions. Cessation of the gastric motility also occurred when 100 µg glucagon or 50 µg epinephrine were given to fed animals pretreated with 2 u insulin. It was found that changes in carbohydrate utilization induced by glucagon preceded the gastric phenomena.
Movement of water, sodium, chloride and hydrogen ions across the resting stomach
Authors: Bornstein Alan M. , Dennis Warren H. , Rehm Warren S.
Published: December 2017

Since during secretion chloride ion is transported against its electrochemical potential gradient, it has been postulated that the potential difference (P.D.) across the mucosa results from the Cl– transporting mechanism. The present experiments were designed to find out if Cl– is transported against its electrochemical potential gradient in the resting stomach. Using the chambered gastric segment preparation, NaCl and HCl solutions were placed on the mucosal surface. P.D., net volume changes and ionic composition changes were measured. With 0.05 m solutions, Cl– moved against its electrochemical potential gradient and against a water movement. With 0.05 m NaCl, the Na+ ion moved ISF to lumen. With 0.15 m NaCl the Na+ and Cl– moved lumen to ISF (Na+ with and Cl– against their electrochemical potential gradient). H+ ions are absorbed from both 0.05 and 0.10 m HCl. Water moved ISF to lumen with 0.20 m NaCl. It is concluded that NaCl and water move in the direction of their chemical potential gradients in the resting stomach. The resting potential is discussed relative to these findings.
Heart activity during experimental diving of snakes
Authors: Johansen Kjell
Published: December 2017

Diving bradycardia has been demonstrated in snakes, ( Tropidonotus natrix). The bradycardia was developed rapidly and amounted to a reduction in heart rate of about 85%. The electrocardiographic findings revealed the slowing of the heart rate as effected mainly through a prolongation of the diastole, amounting to 30 times the prediving value. Duration of the electrical systole showed a prolongation of the P-R interval by 15% and the Q-T interval by 130%. A rapid and pronounced shift in the T-wave amplitude occurred upon submersion. The results suggest that the described T-wave shifts are due to changes in concentration of CO2 in the organism. Increased concentrations of CO2 in the respiratory air induced bradycardia and had a depressant effect on respiration.
Effect of goitrogens on adrenal gland of the rat
Authors: McCarthy J. L. , Corley R. C. , Zarrow M. X.
Published: December 2017

Seven goitrogens were studied to determine whether adrenal atrophy was a characteristic response to administration of antithyroidal agents. Treatments consisted of administration of thiouracil (0.1%), Tapazole (Lilly, 0.001%, 0.005% and 0.01%) and potassium perchlorate (1%) in drinking water and feeding of low iodine diet, p-aminosalicylic acid (PAS, 1%, 2%, 4%), p-aminobenzoic acid (PABA, 2%, 4%) and sulfaguanidine (2%, 4%) in the diet. After 12 weeks of treatment, the animals were anesthetized with sodium pentobarbital, blood was withdrawn by cardiac puncture for steroid analyses and the weights of the pituitary, thyroid, adrenal and thymus glands were determined. Treatment with thiouracil, Tapazole, perchlorate, PABA and sulfaguanidine induced an atrophy of the adrenal gland. Administration of PAS and the low iodine diet brought about hypertrophy of the thyroid gland without adrenal atrophy. Feeding with PABA, at the level of 2% in the diet, induced adrenal atrophy without thyroid hypertrophy while at the 4% level both thyroid hypertrophy and adrenal atrophy occurred. PABA at both dose levels brought about a shift in plasm corticoid levels. Plasmaa from rats given PABA was found to contain little or no corticosterone while the concentration of 17-hydroxycorticoids was markedly increased.
Effect of hypophysectomy on liver enzymes involved in glycogenolysis and in glucogenesis
Authors: Weber George , Cantero Antonio
Published: December 2017

The effect of fasting on liver enzymes involved in glucose-6-phosphate production by glycogenolysis (phosphoglucomutase) and by gluconeogenesis (phosphohexoseisomerase, fructose-1, 6-diphosphatase) was studied in normal and hypophysectomized rats. In normal animals the nitrogen content of the average liver cell decreased to 56% at the end of 6 days starvation. In hypophysectomized rats, however, 1-day fasting was sufficient to decrease nitrogen content to 50%. Liver fructose-1,6-diphosphatase activity was preferentially maintained in normal animals as compared to nitrogen level during 6 days fasting. Hypophysectomy abolished this preferential maintenance and the enzyme dropped after 24 hours fasting below the level observed in normal animals after 6-day fast. One-day fasting in hypophysectomized animals reduced phosphohexoseisomerase and phosphoglucomutase activities to the level reached after 6-day fasting in normal rats. It appears that the breakdown in the normal metabolic adaptation to acute starvation is reflected in the ability to maintain the level of liver enzymes which produce glucose-6-phosphate. The physiological maintenance of hepatic fructose-1,6-diphosphatase, phosphohexoseisomerase and phosphoglucomutase depends, partially at least, on pituitary function.
Orally administered antibiotics in burn shock
Authors: Balikov Bernard , Deadrick Ruth J. , Brame Russell E. , Harrison Charles S.
Published: December 2017

Neomycin was given to rats by stomach tube prior to their being subjected to burn shock. When compared with controls, the combined results of several experiments showed an increase in the survival time of the treated rats which was significant at a P level of between 0.01 and 0.025. The beneficial effect of this neomycin prophylaxis could not readily be explained. Limited experimentation did not support the view that either a reduction in the bacterial population of the intestine or the total elimination of a particular bacterial species or genus could account for this effect. These possibilities, however, were not completely ruled out by our experiments.
Adrenal medullary secretion in hemorrhagic shock
Authors: Walker William F. , Zileli M. Sherefettin , Reutter Fritz W. , Shoemaker William C. , Friend Dale , Moore Francis D.
Published: December 2017

Hemorrhage experiments both of an acute and chronic type were carried out in dogs. The adrenal vein was cannulated as in the previous experiments. There were 10 dogs studied during acute hemorrhage and 4 dogs in chronic hemorrhage. Blood loss in these animals produced an immediate and marked increase in concentration of the catechol amines in the adrenal vein blood, this increase being in proportion to the fraction of the total blood volume removed. The increase was due primarily and initially to an increase in concentration of epinephrine rather than norepinephrine in the adrenal venous blood. The maximum output of catechol amines occurred at a variable time and was then followed by a gradual decline. Early retransfusion of the lost blood or replacement by blood substitute immediately and drastically reduced the catechol amine output. The peripheral arterial blood concentrations of epinephrine were higher than the venous blood concentrations and appeared to be more closely correlated with the concentrations in adrenal venous blood. Infusions of norepinephrine in two dogs increased the output of epinephrine and norepinenephrine in the adrenal vein blood. There was no sign of adrenal medullary failure in dogs dying from shock due to blood loss, even when these dogs accepted blood from an upbleeding (Lamson) bottle by ‘taking up.’
Occult intravascular clotting by means of intravenous injection of thrombin
Authors: Quick Armand J. , Hussey Clara V. , Harris John , Peters Kenneth
Published: December 2017

On infusing a dilute solution of thrombin intravenously into a dog at a constant and carefully regulated rate, no massive thrombosis occurs and no evidence of a thrombo-embolic state is obtained. An occult type of intravascular clotting is produced which is characterized by a progressive decrease of the level of fibrinogen, thrombocytopenia, a prolonged prothrombin time and a poor consumption of prothrombin. Labile factor (factor V) and thromboplastinogen (factor VIII) are strikingly diminished. Prothrombin is moderately decreased while stable factor (factor VII) and PTC (factor IX) are not significantly affected. It is postulated that the adsorption of thrombin to the fibrin fibrils which are filtered off in the capillary network and destroyed, constitutes the principal means for preventing dangerous accumulation of thrombin in the blood.
Effects of estrogen and progesterone on single uterine muscle fibers in the rat
Authors: Marshall Jean M.
Published: December 2017

Ovariectomized white rats were treated as follows: group 1, 6.0 µg estradiol benzoate daily for 5 days; group 2, 6.0 µg estradiol for 3 days, then 1.6 µg estradiol plus 12 mg progesterone for 5 days; group 3, untreated controls. Membrane potentials were recorded from single uterine fibers, tension from the entire uterus. Untreated control fibers were quiescent, having a mean resting potential of 35.2 mv. Estrogen-dominated fibers were rhythmically contractile and had a mean resting potential of 57.6 mv. A train of action potentials accompanied and preceded each contraction of the muscle. In certain areas the fibers showed pacemaker-like characteristics, i.e. slow membrane depolarization between action potentials. Progesterone-dominated fibers had significantly higher resting potentials, mean 63.8 mv, but no localized pacemaker areas. Action potentials did not consistently precede or accompany contractions. In groups 1 and 2, acetylcholine stimulated contractions, lowered the membrane potential and increased the discharge rate of action potentials. Epinephrine diminished contractions, raised the membrane potential and abolished the action potential discharge.
Thyroid state and working for heat in the cold
Authors: Laties Victor G. , Weiss Bernard
Published: December 2017

Four experiments were conducted in which rats in a cold room were allowed to obtain a burst of heat from a heat lamp by pressing a lever. When working at 2°C, hypothyroid rats began to work for heat at a steady rate earlier in a 16-hour session than did euthyroid rats. This rate itself was both higher and more steady for hypothyroid than for euthyroid rats. Euthyroid and hypothyroid rats working at 5°C showed a difference only in time required to attain their steady rate. In one experiment, the chronic administration of l-triiodothyronine to hypothyroid rats led to a significant decrease of lever presses as compared to the performance of normal rats. Discontinuance of l-triiodothyronine led to a gradual recovery of the high rate. The differences in this kind of behavior between hypothyroid and euthyroid animals were attributed to differences in drive state arising from the tendency of body temperature of hypothyroid animals to decline more rapidly in the cold.
Effect of intravenous infusions of calcium on renal concentrating ability
Authors: Beck David , Levitin Howard , Epstein Franklin H.
Published: December 2017

Acute hypercalcemia was produced by infusing calcium gluconate intravenously in dogs undergoing mannitol diuresis. The fraction of filtered sodium which was reabsorbed decreased, in association with a fall in glomerular filtration rate. Slight to moderate decreases in TcH2O were observed, but urine did not become hypotonic to plasma.
Myocardial capillaries in rats with cobalt-induced polycythemia
Authors: Becker E. Lovell
Published: December 2017

Studies have been carried out on normal male and female rats of the Carworth-Nelson strain to ascertain myocardial capillary change after cobalt-induced polycythemia. There was a significant increase in blood hemoglobin and hematocrit, but there was no significant increase in the number of myocardial capillaries. There was a statistically significant increase in the ratio of capillary to tissue area. These results secondary to polycythemia were interpreted as suggesting engorgement of capillaries or dilatation of capillaries not readily visible in control animals.
Conduction block in mammalian nerve produced by O2 at high pressure
Authors: Perot Phanor L. , Stein S. N.
Published: December 2017

Oxygen at high pressure causes a block of conduction in the peripheral nerves of mammals. The interval between initiation of exposure to high oxygen pressure and the onset of block is inversely related to the partial pressure of the oxygen. If the block is not maintained for more than a few minutes, recovery of the ability to conduct returns to the nerve upon decompression. The sensitivity of mammalian nerve to the toxic effects of oxygen at high pressure is decreased when the partial pressure of carbon dioxide in the atmosphere is high, whereas if the partial pressure of carbon dioxide in the atmosphere is lower than normal, the sensitivity of the nerve to the effects of high pressure oxygen increases. This is contrary to the effect carbon dioxide has on oxygen toxicity in frog peripheral nerves. Increased metabolic activity, as occurs at high stimulation frequencies, shortens the time required for block; decreased metabolic activity, as occurs when nerves are cooled, delays the onset of block.
Antithyroxine effects of some thyroxine analogues
Authors: Pittman Constance S. , Barker S. B.
Published: December 2017

Several diiodo- and triiodothyronines and their propionic and acetic acid analogues were evaluated for thyroxine-antagonizing capacity. The postabsorptive metabolic rate of thyroidectomized rats maintained on 20 µg L-thyroxine/ kg/day was used as the criterion, to avoid involvement of endogenous thyroid hormone secretion. At an inhibitor to thyroxine molar ratio of 100:1, 3,3',5'-triiodothyronine, 3,3',5'-triiodothyropropionic acid, 3,3'-diiodothyronine and 3,3'-diiodothyropropionic acid completely suppressed the thyroxine effect on metabolic rate. At the same molar ratio, the corresponding diiodo- and triiodothyroacetic acids produced only about 50% inhibition.
Comparison of renal excretion of rubidium and potassium
Authors: Kunin Arthur S. , Dearborn Earl H. , Burrows Belton A. , Relman Arnold S.
Published: December 2017

The simultaneous renal clearances of rubidium and potassium were studied during the infusion of solutions of rubidium chloride into intact anesthetized dogs. The effects of prior loading with potassium were studied, as were also the responses to acute administration of acetazoleamide and meralluride. It was observed that the clearance of rubidium was usually slightly less than that of potassium and tended under most circumstances to vary in parallel with it. During infusion of RbCl the clearance of rubidium was usually less than the glomerular filtration rate and was independent of plasma level when the latter was varied from 1.0 to 5.0 mEq/l. However, net secretion of rubidium, as well as of potassium, could be demonstrated during periods of reduced filtration rate following administration of acetazoleamide. In the present experiments there was no evidence of interionic competition, but this possibility has not been critically tested. It is concluded that rubidium and potassium are probably handled by similar, if not identical, tubular mechanisms. The secretion of rubidium appears to be slower than that of potassium.
Factors influencing food intake of rats fed low-protein rations
Authors: Meyer J. H. , Hargus W. A.
Published: December 2017

Rats fed low-protein rations increased food intake, weight gain and gain in lean body mass when forced to expend energy by low environmental temperature or exercise (swimming). Rats fed low-protein rations with a higher proportion of fat in their weight gain had a greater food intake and gain in lean body mass. Therefore, gain in lean body mass was improved not only by stimulating energy loss by cold environment or exercise but by an innate ability to deposit more fat in the weight gain, because of an increased food intake, and hence protein intake.
Measurement of thyroid secretion rate of individual pigeons
Authors: Grosvenor Clark E. , Turner Charles W.
Published: December 2017

A method is described in which, by the use of radioiodine techniques, thyroid function of unanaesthetized pigeons was studied. Maximum accumulation of I131 in the pigeon thyroid was accomplished within 24 hours or less followed by rapid thyroidal-I131 release. (Average biological half-life of 2.73 ± .3 days.) Estimation of thyroid secretion rate (TSR) was then made for each pigeon by injecting graded doses of l-thyroxine until the level was reached which suppressed thyrotropic hormone secretion and thus prevented further thyroidal-I131 output. Individual TSR ranged from 1.0–2.5 µg/100 gm/day with an average for 35 adult common pigeons of 1.94 ± .07 µg/100 gm/day l-thyroxine. Analyses of correlation coefficients indicated a significant negative correlation existed between TSR and biological half-life of thyroidal-I131. Nonsignificant correlations existed between TSR and 24-hour I131 uptake and between TSR and body weight. The level of thyroid hormone secretion did not influence the pigeons' crop-sac response to standard lactogenic hormone.
Oxidation of exogenous substrates by isolated human spermatozoa
Authors: Terner Charles
Published: December 2017

In view of the uncertainty whether human spermatozoa display a true oxidative activity, this question was reinvestigated with the aid of C14-labeled substrates. The spermatozoa were isolated from the seminal plasma by centrifugation and resuspended in calcium-free phosphate saline. The radioactive CO2, produced during aerobic incubation of the sperm suspension with C14-labeled glucose, pyruvate or acetate, was collected and from its amount and radioactivity the rates of oxidation to CO2 and H2O of the various substrates were calculated. The results show that of the three substrates tested glucose and pyruvate were oxidized more readily than acetate. The addition of 10–4 m 2:4-dinitrophenol resulted in the acceleration of the rates of oxidation of glucose and of pyruvate, but had no inhibitory effect on the oxidation of acetate. These observations are evidence of the existence of an actively functioning oxidative enzyme system in human spermatozoa.
Incorporation of C14-amino acids into protein of isolated diaphragms: effect of epinephrine and norepinephrine
Authors: Wool Ira G.
Published: December 2017

When diaphragms isolated from normal rats were incubated with a C14-amino acid the addition of epinephrine or norepinephrine decreased incorporation of C14 into muscle protein. The inhibition occurred whether epinephrine was added in vitro or administered in vivo. The minimal effective concentration of epinephrine in vitro was 0.1 µg/ml. When the glucose concentration in the medium was raised to 300 mg % or more the epinephrine induced inhibition of amino acid incorporation into muscle protein was no longer observed.
Adrenal cortical hormone and incorporation of C14 from amino acid precursors into muscle protein
Authors: Wool Ira G. , Weinshelbaum Edward I.
Published: December 2017

The incorporation of C14 from labeled glucose, carboxylic acids and bicarbonate into the protein of isolated rat diaphragm was enhanced by adrenalectomy and decreased by cortisone treatment. The incorporation of radioactivity from pyruvate-3-C14 into the protein of diaphragms from adrenalectomized rats was not appreciably altered by a 20-fold change in pyruvate concentration. Incorporation of C14 from glucose-1-C14 and from glucose-6-C14 was the same, as was the magnitude of the increase after adrenalectomy.
Thermoregulatory responses to hypothalamic cooling in unanesthetized dogs
Authors: Hammel H. T. , Hardy J. D. , Fusco M. M.
Published: December 2017

A method is described for local heating or cooling of regions of the hypothalamus of the intact unanesthetized dog. Needle thermodes carrying warm or cold water are inserted through metal guides fixed permanently in the skull and placed symetrically across the mid-line thus permitting the controlled raising or lowering of the hypothalamic temperature. Insertion of the thermodes is painless and causes no hyperpyrexia or other reaction. The thermodes are withdrawn at the end of an experimental period and the animal can be used repeatedly without ill effects. The following observations were made: a) mild cooling causes vasoconstriction and shivering. There is a marked rise in internal temperature and in temperature of skin over trunk as the result of increased heat production. There is also a large drop in skin temperature of extremities as the result of vasoconstriction. b) With continued cooling, shivering weakens and finally ceases; vasoconstriction continues but rise in body temperature slows. c) Rapidly alternating heating and cooling permits the simultaneous stimulation of panting and shivering responses. These observations suggest that in the hypothalamus there are areas sensitive to cooling, which have thermoregulatory responses. As a result of continued cooling of these regions, inhibitory responses are also evoked which are probably associated with warmth stimulation due to elevated skin and internal body temperature outside of the hypothalamus.
Interrelation between renal transport systems of magnesium and calcium
Authors: Samiy A. H. E. , Brown J. L. , Globus D. L. , Kessler R. H. , Thompson D. D.
Published: December 2017

Infusion of magnesium chloride markedly increased the excretion of calcium in dogs. A slight but significant increase in the excretion of magnesium occurred following the infusion of calcium chloride. Utilizing the stop-flow technique it was noted that magnesium and calcium achieved minimal concentration ratios in the distal segments of the nephron. Infusion of magnesium chloride during stop-flow studies increased U/PCa/U/PCr ratios both in the proximal and distal samples. These observations support the postulate that magnesium and calcium compete for a common reabsorptive system in the renal tubules. In several stop-flow experiments Mg28 and Ca45 were injected along with inulin 1 or 2 minutes before releasing the ureteral occlusion. Mg28 and Ca45 appeared simultaneously in the urine prior to the appearance of inulin, suggesting transtubular flux of these cations. Such observations, while indicating bidirectional movement of these ions across the tubular epithelium, do not imply active or net secretion.
Evidence for the existence of a gastropancreatic reflex
Authors: White Thomas Taylor , Lundh Göran , Magee Donal F.
Published: December 2017

The effect of distention of the stomach on pancreatic secretion was studied in conscious dogs which had chronic pancreatic fistulae. The results obtained are given. a) In 37 experiments on 23 dogs the average rate of pancreatic secretion was 1.7 cc/20 minutes, while after inflation of a condom in the stomach with 250–400 cc of air the secretion increased in every dog to an average of 4.2 cc/20 minutes (147% change). This was accompanied by an increase in protein production of 98.7%. In five dogs receiving maximal stimulus from continuous secretin, there was a further rise in volume and protein following gastric distention. b) Subcutaneous transplants of the pancreas responsed to secretin but not to gastric distention. c) Distention of four total innervated gastric pouches produced the same increase in volume and protein as distention of intact stomachs. d) Increased secretion was not observed after distention in vagotomized or atropinized dogs or dogs with procaine block of the vagus in the neck. e) An increase in rate of secretion and protein occurred after distention of the stomach in two human subjects with pancreatic fistulae.
Metabolism of sulfate by beef and rabbit cornea
Authors: Wortman Bernard
Published: December 2017

Beef and rabbit corneal stromas will incorporate inorganic sulfate-S35 in vitro. Species differences with respect to the influence of epithelium on this uptake and the distribution of phenol sulfokinase and of arylsulfatase in various parts of cornea have been observed. Rabbit stroma is dependent upon an intact epithelium for its uptake but de-epithelialization is without effect upon the uptake of inorganic sulfate-S35 into beef stroma. Beef cornea epithelial, stromal and endothelial extracts were found to contain phenol sulfokinase and no detectable arylsulfatase activity. The latter enzyme was found in rabbit cornea stromal extract but not in epithelial-endothelial extract. Arylsulfatase has been partially characterized. Nitrocatechol sulfate and p-nitrophenyl sulfate were hydrolyzed at the rate of 280 and 30 mµmoles/hr/mg of extract protein at their pH optima 5.5 and 7.4 at 38°, respectively. The effect of various known arylsulfatase inhibitors was observed, and the results suggested two arylsulfatases. Efforts to find two separate arylsulfatase activities after electrophoresis of rabbit corneal extract on starch were inconclusive.
Role of the kidney in plasma albumin catabolism
Authors: Katz Joseph , Rosenfeld Sheldon , Sellers Alvin L.
Published: December 2017

The role of kidneys in the breakdown of plasma albumin was investigated. The rate of iodoalbumin breakdown by bilaterally nephrectomized rats and in isolated perfused rabbit kidney were studied. Homologous I131-labeled plasma albumin was used. To remove denatured components, the iodoalbumin was ‘screened,’ that is, it was injected into animals which were bled several days later, and whole plasma was used as the iodoalbumin substrate. It was found that bilateral nephrectomy reduced unscreened iodoalbumin breakdown by about 20% but had no effect on the breakdown of screened iodoalbumin. Unscreened iodoalbumin was broken down at an appreciable rate by perfused kidney, but with screened iodoalbumin the breakdown rate was greatly reduced. It is concluded that, at most, 10% of the turnover of native plasma albumin in the body may occur in kidneys.
Stop-flow analysis of renal reabsorption and excretion of sulfate in the dog
Authors: Hierholzer Klaus , Cade Robert , Gurd Ruth , Kessler Richard , Pitts Robert
Published: December 2017

Utilizing the stop-flow technique, the site of reabsorption of inorganic sulfate has been localized in the proximal part of the nephron of the dog. Sulfate is most avidly reabsorbed in that portion of the proximal tubule which most actively secretes PAH. No evidence of secretion of inorganic sulfate in any part of the nephron or of reabsorption of inorganic sulfate in more distal parts of the nephron has been found. However, the infusion of large quantities of sodium sulfate activates the mechanisms of urinary acidification and of potassium and ammonia secretion located in the terminal nephron. This activation is similar to that induced by sodium phosphate and by sodium ferrocyanide and is interpreted as resulting from the presence of unreabsorbed anion in distal tubules and collecting ducts. The infusion of glycine specifically stimulates ammonia secretion.
Mechanism of hemolysis after intravenous glycerol administration
Authors: Pinter Gabriel G. , Zilversmit D. B.
Published: December 2017

Concentrated glycerol solutions in 0.9% saline, when administered intravenously to rabbits and rats, caused considerable intravascular hemolysis, but similar solutions given to dogs had no hemolytic effect. Perfusion of the partially isolated hind leg of the rabbit with Cr51-tagged and glycerol-containing red cell suspensions showed hemolysis of only those cells containing glycerol. This observation eliminates a hemolysin as the cause for the hemolysis. In vitro experiments showed that glycerol penetrates the erythrocytes of rats, rabbits and man quite rapidly, whereas the cells of dogs were penetrated at a much slower rate. It is suggested that the intravascular hemolysis caused by intravenous glycerol is produced by the rapid uptake of glycerol by the erythrocytes and a subsequent osmotic imbalance caused by the rapid decrease of glycerol concentration in the circulating plasma. It is proposed that this mechanism is a general one and explains, for example, the intravascular hemolysis caused by the intravenous injection of hyperosmotic urea dissolved in 0.9% saline.
Distribution and hematocrit ratios of blood in the rat
Authors: Dewey William C.
Published: December 2017

The distribution of blood in the rat was investigated with Cr51 red blood cells and I131 plasma proteins. The hematocrit of blood obtained by decapitation may be assigned the value of 100. Then, the hematocrit of blood draining from the tissues was found to be 100, and for that which remains in the tissues the figure was 57. Since this fraction in the tissues was 18% of the blood volume, the hematocrit for the whole body must be between the two; the value found was go.
Maternal behavior in the rabbit: hair loosening during gestation
Authors: Sawin P. B. , Denenberg V. H. , Ross Sherman , Hafter Erwin , Zarrow M. X.
Published: December 2017

A method is presented for determining the degree of hair loosening in the rabbit by weighing the amount of hair obtained through a standardized combing technique. The results indicate that significant hair loosening occurs during gestation in the rabbit. The time of hair loosening may vary from the 5th day prepartum to the day of parturition and in one instance the phenomenon failed to appear. The response of hair loosening is believed to be a component of the nest building-maternal behavior complex in the rabbit. The loosened body hair is used in nest construction.
Dual action of maltoxin, a neuromuscular blocking agent from malt rootlet
Authors: Urakawa Norimoto , Narahashi Toshio , Deguchi Takehiko , Ohkubo Yoshio
Published: December 2017

Maltoxin, an amine obtained from brew malt rootlet, causes a neuromuscular block in the frog. Its mode of action on the frog's sartorius muscle has been studied mainly with the aid of intracellular microelectrodes. Maltoxin of 10–5 concentration caused an over-all depolarization of the muscle fibers; therefore, direct and indirect stimulations of the muscle were ineffective in producing muscle action potential. Progressive repolarization took place thereafter and the muscle became excitable by direct stimulation, though indirect stimulation remained ineffective for a long period of time. Small end-plate potentials observed could not be explained in terms of depolarization. It was found that the sensitivity of the end-plate membrane to acetylcholine was effectively depressed by maltoxin, and that this is responsible for the persistent neuromuscular block. The initial over-all depolarization caused by maltoxin was fairly antagonized by a previous treatment with d-tubocurarine. It is concluded that maltoxin has a dual mode of action, having some resemblance to acetylcholine, decamethonium, succinylcholine and nicotine.
Distribution of Na and K in various regions of isolated rabbit atria
Authors: Holland W. C.
Published: December 2017

The effects of varying the extracellular K concentration (K0), ouabain (10–6 m) and acetylcholine (10–5 m) on the Na and K content of the pacemaker region, right atrium, and left atrium have been investigated. The Na content is higher, and K content lower in pacemaker, as compared to atria. Increased K0 elevated K in atria, but had no effect on nodal K. Ouabain caused a net loss of K from atria, but had no effect on pacemaker K. At low K0 acetylcholine reduced K in all regions, while at high K0 this agent increased atrial cell K. It is concluded that ‘active transport’ mechanisms are absent or reduced in pacemaker tissue.
Blood-brain barrier behavior during temporary concussion
Authors: Cassen Benedict , Neff Richard
Published: December 2017

Experimental evidence is obtained that, coincident with a state of not too severe concussion, the blood-brain barrier system becomes more permeable to phosphate ions. The permeability returns to normal when the animal recovers and shows normal activity. Arguments are presented in favor of the hypothesis that dysfunction of the central nervous system during concussion is related to a disturbed electrolyte balance in the fluids of the brain caused by a piezochemical disturbance of the blood-brain barrier membranes (presumably the astropods of the astrocytic cells).
Effect of procaine hydrochloride on the pyloric sphincter
Authors: Louckes H. S. , Quigley J. P.
Published: December 2017

The effect of intragastrically and intravenously administered procaine hydrochloride on the pyloric sphincter motility of two well-trained, unanesthetized dogs was studied by the inductograph method. Intragastrically or intravenously administered procaine hydrochloride in moderate doses had little effect on the motor activity of the pyloric sphincter. Larger doses of intragastrically or intravenously administered procaine hydrochloride produced signs of CNS stimulation, particularly of the vomiting centers, and the characteristic inhibition of the sphincter activity during nausea and tetanic contraction of the sphincter during vomiting. When intragastrically administered procaine significantly altered pyloric sphincter motility, it apparently resulted from CNS effects following procaine absorption from the gut.