bluuebunny/crossref_metadata_2025 huggingface dataset:
Increase in weight of the submandibular salivary glands of rats following periodic amputation of the erupted portion of the incisor teeth
Authors: Wells Herbert , Zackin S. Jerome , Gold-Haber Paul , Munson Paul L.
Published: December 2017

Periodic amputation of the erupted portion of the lower incisors of albino rats resulted in a marked increase in the wet and dry weight of the submandibular salivary glands as early as 7 days after the first amputation. Enlargement of both serous and mucous acini was observed, but no effect on the cells of the tubules could be detected. Amputation of the upper incisors alone did not result in enlargement of the submandibular glands. Hypophysectomy decreased the extent of the response to amputation of the lower incisors but did not abolish it. Chronic treatment with cortisone had no significant effect on the weight of the glands. A reflex neurologic explanation was offered as a tentative basis for understanding the phenomenon and as a starting point for further investigation.
Hepatic function of the golden hamster after exposure to cold and during hibernation
Authors: Harrington Joseph D. , Nardone Roland M.
Published: December 2017

The effect of forced hypothermia, long term cold exposure and hibernation on liver function of the golden hamster, Mesocricetus auratus, was studied in order to ascertain the role of the liver in survival of a hibernator under cold stress. The bromsulphalein test for liver function indicated no liver damage from forced hypothermia and 3.5% liver impairment from long term cold exposure. The colloidal red flocculation test for liver function showed an upset of serum albumin/globulin ratio after long cold exposure and during hibernation. This is correlated with prolongation of blood clotting time observed during hibernation. These factors are used to exemplify the importance of the liver in hibernal physiology.
Effect of heat and solar radiation on vitamin A utilization by the bovine animal
Authors: Page H. M. , Erwin E. S. , Nelms G. E.
Published: December 2017

During trial I, twin calves, fed 6 mg carotene daily per 100 lb. body weight, were subjected to high and low ambient temperatures. Differential liver vitamin A analyses indicated that high ambient temperatures predisposed an increased liver vitamin A expenditure. In the first phase of trial II, identical twin calves exposed to solar radiation ( SR) for 38 days lost more hepatic vitamin A than their co-twins in the shade ( S). Following vitamin A administration, SR stored more hepatic vitamin A than S. Possible mechanisms predisposed by heat stress, that alter vitamin A metabolism, were discussed.
Effect of acetazoleamide alone and during asphyxia on hippocampal and cortical activity in the marsupial phalanger
Authors: Dunlop C. W.
Published: December 2017

The effects of asphyxia and acetazoleamide on evoked hippocampal and cortical activity in the marsupial phalanger were determined. During asphyxia the evoked hippocampal activity was affected before the evoked cortical activity. Acetazoleamide administered prior to asphyxia caused inhibition earlier during asphyxia and prolonged the recovery period of the evoked activity in both regions. Acetazoleamide gave only slight protection in the hippocampus against electrically induced seizures. The peak effect of the drug was reached 4 hours after administration and then declined gradually.
Effect of endotoxin on renal function in the dog
Authors: Hinshaw Lerner B. , Bradley Gloria M. , Carlson Curtis H.
Published: December 2017

Studies were made on isolated and intact dog kidneys provided with a controlled renal arterial perfusion pressure. Renal function tests were performed for a period of 1–2 hours. Creatinine and PAH extraction ratios, clearance rates and TmPAH values were calculated. A procedure was devised for the calculation of renal clearances from simultaneously occurring values which obviated errors due to urinary dead space and permitted the measurement of rapid changes in extraction rates. Renal blood flows and urine flows were measured. After administration of endotoxin PAH extraction ratios and extraction rates declined. TmPAH values temporarily fell but within an hour returned to pre-endotoxin levels. Creatinine extraction ratios and rates and urine flow showed irregular changes after endotoxin. Renal hyperemia was observed if the arterial pressure was maintained and especially when smaller injections of endotoxin were administered. It is concluded that the effect of endotoxin on the kidney is primarily a vascular one. There is no evidence for the poisoning of renal tubule cells, and renal vascular occlusion is not observed.
Contrasting effects of stress and cortisol overdosage in the rat
Authors: Hall C. E. , Hall O.
Published: December 2017

Immature female albino rats were subjected to chronic stress and to cortisol overdosage singly and in combination. At a dosage of 1 mg/day the steroid produced slight augmentation of blood pressure, moderate inhibition of growth and great involution of the thymus. Stress, in the form of intermittently applied electrical shocks, although it had little effect on the thymus or on body growth, produced slight adrenal hypertrophy and a considerable hypertrophy of the preputial glands. Stress and cortisol together acted synergistically on body growth and thymus involution; but cortisol dominated the adrenal response and stress that of the preputial glands. There was only suggestive evidence that blood pressure effects of cortisol were augmented by stress. The possible usefulness of preputial hypertrophy in the assessment of chronic stress states is discussed.
Incorporation of C14-amino acids into protein of isolated diaphragms: an effect of insulin independent of glucose entry
Authors: Wool Ira G. , Krahl M. E.
Published: December 2017

The effect of glucose concentration and insulin on protein synthesis was investigated using the isolated rat diaphragm and C14-labeled amino acids. When the donor rat has been well fed, the incorporation of histidine-2-C14, lysine-2-C14, phenylalanine-3-C14, and alanine-1-C14 into muscle protein is uninfluenced by glucose concentration in the medium over the range 0–600 mg %. Insulin leads to an increase in C14-amino acid incorporation into muscle protein in the absence of glucose in the medium. This positive effect of insulin in the absence of added glucose is still observed when the diaphragms are pre-incubated for 2 hours prior to adding insulin. These findings suggest an effect of insulin on protein metabolism independent of its action in promoting glucose entry.
Augmentation of mouse thyroid iodide pump activity after withdrawal of propylthiouracil
Authors: Lipner H. J. , Wagner Billie P. , Morris Harold P.
Published: December 2017

The chronic administration of propylthiouracil for 16–30 days to mice resulted in either no increase or depression in the specific activity of the thyroid iodide pump. Within 24 hours after the withdrawal of propylthiouracil from the diet there occurred an augmentation of the specific activity of the iodide pump. The total activity of the thyroid pump behaved in a similar manner. The disassociation of pump activity from growth suggests that in the mouse these parameters of thyroid function are independent processes.
Response of the normal and thyroidectomized cat to serve cold
Authors: Boatman Joseph B.
Published: December 2017

Anesthetized, artificially respired normal and thyroidectomized cats were subjected to –20°C air temperature following 1 hour equilibration at room temperature. Blood pressure, heart rate, I131 albumin blood volume, Na24 dilution volume, hematocrit, and rectal, subdermal, intra-abdominal and esophageal temperatures were measured continuously until arterial blood pressure was absent. At room air temperature thyroidectomized animals had lower body temperatures, blood pressure, heart rate and plasma volumes, and greater Na24 dilution volumes and plasma hematocrits. Both groups exhibited similar responses to sudden and severe cold: immediate increases in heart rate and blood pressure were followed by a sharp and continuous decline. Simultaneously occurred an abrupt decrease in plasma hematocrit, a sudden Na24 volume increase and a decrease of plasma volume. The rates of change of all indices were greater in the thyroidectomized group. Thyroidectomized animals were characterized by a more rapid rate of cooling, most marked in peripheral areas, and Na24 dilution volumes indicated a greater extravascular volume of fluid entered by the sodium isotope. It is concluded that thyroidectomy prior to cold exposure makes heat conservation responses less efficient than in the normal animal and that the intact thyroid plays a role in maintaining body fluids in an efficient equilibrium for rapid adjustment to a cold environment.
Evoked potentials in the hypothalamus
Authors: Feldman Shaul , Van der Heide Charles S. , Porter Robert W.
Published: December 2017

The distribution and some properties of the evoked potentials in the hypothalamus from stimulation of the sciatic nerve were investigated in 60 cats. In the posterior and lateral hypothalamus biphasic positive-negative responses of 7–10 msec. latency were found, while in the anterior and medial hypothalamus the stimuli evoked monophasic negative waves of 20–35 msec. latency. The threshold of activation of the hypothalamic potentials corresponded to the upper range of activation of group A fibers in the sciatic nerve. The hypothalamic evoked potentials had a very prolonged recovery time on double stimulation, were sensitive to pentobarbital even to a greater degree than the evoked potentials in the midbrain reticular formation, and were abolished by high frequency stimulation of the midbrain reticular formation. The long latency potentials in the hypothalamus were similar to those evoked in the midbrain reticular formation, while the short latency potentials had properties similar to those of the lemniscal potentials. This fact suggested that the short latency potentials signaled the arrival of impulses from lemniscal collaterals.
Influence of LSD-25 on optically evoked potentials in the nonanesthetized rabbit
Authors: Koella W. P. , Wells Charles H.
Published: December 2017

The influence of LSD-25 (i.v.) upon the optically evoked cortical potentials was studied in chronically prepared unanesthetized and noncurarized rabbits over a 23-hour period. With moderate doses of the drug (35 µg/animal) the potentials were enhanced for a period of over 6 hours. The time course of the amplitudes indicates a triphasic pattern. LSD-25 reduced the latency of the potentials by about 10%. LSD-25 was found to have a marked effect upon variability of both the amplitude and the latency. Both these variabilities were greatly reduced for 1–3 hours after injection.
Oxidative processes in hypervitaminosis A in albino rats
Authors: Ray Amal , Sadhu D. P.
Published: December 2017

Albino rats were made hypervitaminotic A by feeding 30,000 iu of vitamin A daily by mouth; the effect of this hypervitaminosis was compared with a similar pair-fed group. Food consumption and body weight gain were reduced. Study of liver and kidney slices shows that the latter manifest no significant increase in oxygen consumption in presence of succinate or acetate. There is slight increase in O2 consumption in brain homogenates. Liver homogenate shows 15.2% inhibition with succinate and 5.6% with ascorbate oxidation. Liver homogenate shows 19.3% inhibition of succinate dehydrogenase activity by Thunberg technique with methylene blue indicator. It is concluded that hypervitaminosis A inhibits liver respiration by affecting the dehydrogenase, or any immediate step following it, and the cytochrome c-cytochrome oxidase end of the succinoxidase system is little affected.
Weight, nitrogen and DNA content of small intestine mucosa of rats exposed to X-rays
Authors: Kay Robert E. , Entenman Cecil
Published: December 2017

The quantitative relationships between the changes in small intestine weight, mucosa weight, mucosa DNA and nitrogen following exposure to x-rays were investigated. It was found that these relationships depend upon the magnitude of the dose, time of observation, nutritional state of the rat and number of doses administered. Thus, depending on the particular combination of these variables, different effects of x-irradiation on mucosa weight, intestine weight and mucosa DNA and nitrogen were observed. The following relationships were found: a) weight changes in the small intestine always reflected the changes in mucosa weight, b) changes in mucosa nitrogen after a single x-irradiation always paralleled the changes in mucosa weight, whereas the changes in mucosa DNA were not as closely related to the weight changes, c) changes in mucosa weight and nitrogen did not correlate well with the dose received, whereas DNA level approximated a linear relationship over the range 300 to 900 r, and d) there was a minimum level to which the mucosa weight, DNA and nitrogen decreased following x-irradiation.
Effect of urea on central nervous system activity in the cat
Authors: Stevenson George C. , Jacobs R. Campbell , Ross M. William , Collins William F. , Randt Clark T.
Published: December 2017

Effects of i.v. infusion of urea were studied in 26 cats by recording spontaneous cortical activity and somatic afferent evoked potentials from the posteroventral lateral nucleus of the thalamus and periaqueductal midbrain reticular formation. Subsequent to the administration of a 20% solution of urea, spindling and seizure discharges appeared in the electrocorticogram. The evoked potentials from the posteroventral lateral nucleus of the thalamus and reticular formation remained unchanged. Control studies indicated that the operative procedure, including the insertion of subcortical electrodes, hydration incident to fluid administration, possible deterioration of the preparation and alteration of the osmolarity of the serum did not produce the observed results. It was demonstrated that urea administered intravenously, in amounts producing blood NPN values commensurate with those observed in patients with uremia, alters cortical activity and excitability.
Washout of renal countercurrent Na gradient by osmotic diuresis
Authors: Malvin Richard L. , Wilde Walter S.
Published: December 2017

The antidiuretic hormone regulates the ability of the kidney to concentrate urine. There are two theories as to the nature of the renal concentrating mechanism: 1) the existence of an active water pump in a distal area which removes free water from the urine and 2) the existence of a countercurrent multiplier system in the renal pyramid which allows for passive movement of water out of the collecting ducts in response to an osmotic gradient. During stop flow, the kidneys are unable to alter appreciably the total osmotic pressure of urine. Measurement of Na concentrations along the length of the renal pyramid may be used as an index of the magnitude of the countercurrent gradient. Such determinations were made before and during mannitol diuresis in dogs. An osmotic gradient along the pyramids was evident in control kidneys and disappeared upon establishment of osmotic diuresis. These data suggest that high rates of urine flow through the loop of Henle may wash out the pre-existing countercurrent gradient. This accounts for the inability of the kidneys to concentrate stop flow urine. It also demonstrates that osmotic diuresis, which is generally thought of as only a proximal event, must also result from diminished distal water reabsorption due to the washout of the countercurrent gradient.
Plasma volume changes accompanying reactions to infusions of blood or plasma
Authors: Remington John W. , Baker Carleton H.
Published: December 2017

Splenectomized dogs were infused serially with 5–10 cc/kg of blood or plasma. There was a high incidence of reactions to the homologous plasma or blood, marked by a fall in arterial pressure, urticaria, cutaneous edema, a prolonged bleeding time, labored respiration and some fatalities. The pressure fall was not seen in anesthetized dogs. The urticaria and skin edema were largely prevented by injections of antihistaminic drugs, but the other reactions were not reduced. In the majority of dogs given homologous blood, the hematocrit showed a steep rise, indicating a disappearance of plasma. The reduced plasma volume was confirmed by T-1824 injections, although the agreement between hematocrit change and plasma volume change by dye was not always quantitative. These changes were not clearly affected by the antihistaminic drugs. However, when dogs were given their own (autologous) plasma, the blood volume increase as measured by dye or calculated from hematocrit change was the same as that expected from the known amount of plasma transfused, corrected for ultrafiltrate shifts. The infusion reactions were also greatly curtailed.
Myocardial sodium and potassium content in relation to blood pressure
Authors: Freed S. Charles , St. George S.
Published: December 2017

In rats made hypotensive through potassium deprivation, there is a slight loss in myocardial potassium but a significant increase in sodium content. Restoration of blood pressure following cortisone or prednisone administration is associated with removal of the excess myocardial sodium. 9α-Fluorohydrocortisone partially reduces the sodium but further decreases the potassium of the heart, resulting in an unchanged high Na/K ratio. No elevation of blood pressure follows its administration. DCA causes a further lowering of blood pressure associated with an even higher Na/K ratio of the myocardium through a decrease in potassium and an increase in sodium contents.
Effects of fasting and insulin on carbohydrate metabolism of the domestic fowl
Authors: Hazelwood R. L. , Lorenz F. W.
Published: December 2017

Prolonged fasting caused a rise in blood glucose which reached a maximum above the prefast level on the 6th day. Concurrently the liver glycogen, rapidly depleted at the start of the fast, was partially replaced. Blood NPN increased continuously. Thus, gluconeogenesis appeared likely not only to be responsible for the blood glucose increase but also to play a role in the restoration of liver glycogen after initial glycogenolysis due to fasting. Fasting for 48 hours increased cardiac glycogen up to three times the prefasting level; a rapid decrease in this moiety occurred with further abstinence. Glucagon and growth hormone increased the cardiac glycogen of nonfasted birds; but had little, if any, influence on the effects of fasting. The daily injection of 60–70 u of either regular or HGF-free insulin per kilogram body weight resulted in an hyperglycemic rebound 24 hours after each injection. This rebound could be blocked completely by feeding Dibenzyline.
Influence of diet on utilization of glucose and incorporation of acetate-I-C14 into liver fatty acids and cholesterol in rats
Authors: Christophe Jean , Mayer Jean
Published: December 2017

A comparative study of glucose utilization, insulin sensitivity and in vivo incorporation of acetate-C14 into liver fatty acids and cholesterol was conducted in male adult rats. These animals were maintained for 4 weeks on three high carbohydrate diets (glucose, fructose or galactose), a high protein diet (casein), a high fat diet (lard) or Ralston Purina laboratory chow. Glucose utilization was high on the glucose diet and low on the fat diet. Incorporation of C14 into liver fatty acids was very high on the fructose diet, high on the protein and glucose diets, low on chow, and very low on the fat diet. Incorporation of C14 into liver cholesterol was relatively high on chow and relatively low on the fat diet. Glucose utilization in prefasted states and incorporation of acetate into liver fatty acids in fed states were roughly parallel on various diets but no correlation could be noted between glucose utilization and acetate incorporation into liver fatty acids on the one hand and incorporation of acetate into liver cholesterol on the other.
Adaptive enzyme responses in the senescent rat: tryptophan peroxidase and tyrosine transaminase
Authors: Gregerman Robert I.
Published: December 2017

Two of the adaptive enzymes of liver, tryptophan peroxidase and tyrosine transaminase, have been determined in mature (12–13 months old) and senescent (24–26 months old) rats. Basal levels of the two enzymes, the increase of tryptophan peroxidase after substrate administration, and of both tryptophan peroxidase and tyrosine transaminase after adrenal cortical hormone (hydrocortisone) have been studied. In both groups of animals the mean enzyme activities were the same in all instances. The data fail to indicate that senescence is accompanied by a biochemically demonstrable impairment of the mechanisms involved in adaptive enzyme formation.
Electrolyte composition of experimental galactose cataracts
Authors: Hill Joseph C. , Heggeness Franklin W.
Published: December 2017

The composition of galactose-induced cataractous lens differs from that of the normal rat lens. Weight is decreased due to loss of both water and organic solids. Within a few days of maturation of the cataracts the sodium and calcium concentrations are increased and potassium is virtually absent from the lens. No differences were found in the water content or electrolyte composition of other nonvascular tissues such as tendon, cornea or cartilage in rats maintained on a high galactose intake as compared to the control group of rats on a glucose diet. Modifications of the diet by the inclusion of sulfasuxidine or by sulfasuxide plus low calcium do not modify the general electrolyte pattern of the cataractous lens. In rats ingesting a high galactose, calcium-deficient diet cataracts develop sooner than in the presence of adequate dietary calcium.
Effect of feeding and sham feeding on pancreatic secretion of the rat
Authors: Alphin R. S. , Lin T. M.
Published: December 2017

The basal spontaneous pancreatic secretion of a chronic pancreatic fistula rat weighing 300–400 gm is approximately 0.33 ml/hr. The mean hourly amylase output is about 4400 mg maltose equivalents. Oral feeding, gastric feeding and sham feeding of a commercial dog food significantly increased the volume flow and the hourly amylase output of rats with pancreatic fistula. Sham feeding did not have this effect on rats provided with a gastric fistula or after vagotomy.
Mechanism of hypothalamic control of gastric contractions in the rat
Authors: Mayer Jean , Sudsaneh Saovanee
Published: December 2017

Gastric hunger contractions in hypothalamic hyperphagic and aphagic rats are similar to those of normal rats. Heat, cold and epinephrine inhibited hunger contractions in both types of hypothalamic animals. The gastric hunger contractions of aphagic rats are inhibited normally by glucagon. However, doses of glucagon which inhibit hunger contractions in normal rats fail to do so in hyperphagic hypothalamic animals whether obese or reduced to normal weight, in spite of the fact that responses are similar to those seen in normal animals. This ventromedial ‘glucoreceptive’ hypothalamic area thus seems to exert a considerable measure of control upon gastric hunger contractions while the lateral area does not. A scheme integrating hypothalamic, metabolic and gastric factors in hunger is proposed.
Effect of potassium on renal vascular resistance and urine flow rate
Authors: Scott Jerry , Emanuel Dean , Haddy Francis
Published: December 2017

The effect of potassium chloride upon renal vascular resistance and urine flow rate was studied in anesthetized laparotomized dogs. Potassium chloride was infused directly into the renal artery with the rate of blood flow to the kidney held constant and with flow rate not controlled. Resistance progressively decreased when serum potassium level in the kidney was elevated by infusing 0.11–0.69 mEq K+/min. It progressively increased when the infusion rate exceeded 0.69 mEq/min. This relationship was unaltered by the adrenergic blocking agent phentolamine. Urine flow rate increased both before and after denervation of the kidney when potassium was infused at the rate of 0.6 mEq/min. This increase was not apparent when the rate of blood flow was held constant. These findings indicate that a local potassium excess in amounts which might occur naturally leads to dilatation of renal vessels and increase of urine flow rate. The latter probably is related to the former.
Incorporation of C14-histidine into protein of isolated diaphragms: interaction of fasting, glucose and insulin
Authors: Wool Ira G. , Krahl M. E.
Published: December 2017

The interaction of fasting, glucose availability and insulin on protein synthesis was investigated using the isolated rat diaphragm incubated in vitro with histidine-2-C14. Prior fasting of the diaphragm donor leads to a decrease in the rate of incorporation of histidine-2-C14 into muscle protein; the decrease after a 12- or 24-hour fast is small, that after a 48-hour fast is marked. A definite influence of glucose concentration can be demonstrated only when the donor rat has been fasted 48 hours; and only in diaphragms from such fasted animals is the insulin anabolic effect dependent on the availability of extracellular glucose.
Vascular-extravascular exchange of I131 plasma proteins in the rat
Authors: Dewey William C.
Published: December 2017

Rates at which plasma proteins penetrate from the vascular system into extravascular spaces in tissues was measured with I131-labeled rabbit gamma globulin, rat gamma and beta globulins, and rat albumin. After vascular mixing was complete, as measured with Cr51-labeled erythrocytes, initial rates of increase in the ratio of tissue radioactivity to plasma radioactivity were used to calculate vascular-extravascular transfer rates; these are reported as grams blood plasma equivalents which penetrate the vascular-extravascular barrier in 1 gm tissue each hour. Transfer rates ranged from 0.06–0.76 for visceral organs to 0.0005–0.005 for tissues such as muscle, fat and skin; the transfer rates were roughly proportional to the vascularity of the tissues. Ratios of tissue to plasma radioactivity reached at equilibrium were used to calculate the amounts of plasma proteins present extravascularly. These protein masses ranged from 0.02 gm plasma equivalents per gm tissue for muscle to 0.13 for skin. Significant differences between the various plasma proteins were found only in the liver, spleen and stomach.
Anoxic endurance of cardiac and respiratory function in the adult and infant rat
Authors: DeHaan Robert L. , Field John
Published: December 2017

In order to provide a quantitative measure of the relative susceptibility to anoxia of infant cardiac and respiratory function, as compared with those of the adult, newborn and adult rats were made to inhale pure nitrogen for varying periods. Care was taken to maintain the body temperature of the infants at a level comparable to that of the adults. The duration of respiratory efforts and of ventricular electrical activity was observed, and the data analyzed by appropriate statistical methods. On a scale of decreasing resistance to the effects of anoxia are to be found: infant rat ventricle; infant rat respiratory center; adult rat ventricle; adult rat respiratory center.
Myocardial metabolic and electrical properties of rabbits and ground squirrels at low temperatures
Authors: Covino Benjamin G. , Hannon John P.
Published: December 2017

When perfused in vitro with Krebs-Henseleit solution both rabbit and arctic squirrel hearts exhibit similar contraction rates in a temperature range of 35°–25°C. Below 25° the rabbit heart was more susceptible to the present effect of cold. A reduction in temperature produced a much more pronounced depression in diastolic ventricular excitability in the rabbit than in the ground squirrel. At any given temperature, both species had quite similar in vitro coronary flow rates. As the perfusion fluid was cooled, however, flow rates of both species were markedly lowered. Ventricular tissue removed from rabbits with rectal temperatures of 15°C showed that a conversion of ATP to ADP had occurred. Lowering of the body temperature to 15°C in squirrels had no effect on ventricular ATP levels. At both normal and hypothermic temperatures, the total ventricular nucleotide content was much higher in squirrels than in rabbits. At 38° and at 15° squirrels exhibited a higher glutamic but a lower ß-hydroxybutyric, malic and succinic oxidase activity than rabbits.
Effect of insulin on membrane potential and potassium content of rat muscle
Authors: Zierler Kenneth L.
Published: December 2017

Insulin increased resting membrane potential of excised rat muscle, extensor digitorum longus, by about 5 mv in less than 1 hour. In 1 hour insulin caused no increase in the ratio of intra- to extracellular potassium, but in 2–3 hours intracellular K increased by about 10%. It is concluded that the increase in intracellular K is probably too small and too late to account for the hyperpolarization on the basis of conventional theory and it is suggested that the hyperpolarization produced by insulin is the cause of the potassium shift.
Reversible conduction block produced by lipid-insoluble quaternary ammonium ions in cetyltrimethylammonium bromide-treated nerves
Authors: Walsh Raymond R. , Deal Stanley E.
Published: December 2017

Frog sciatic nerves were excised and treated in a Ringer's solution containing the surface-active agent, cetyltrimethylammonium bromide (CTMB). Such CTMB-treated nerves were compared to normal, untreated nerves with respect to their susceptibility to conduction block produced by six lipid-insoluble quaternary ammonium ions; the CTMB-treated nerves were rendered especially susceptible to rapid, reversible conduction block. A possible mechanism of CTMB action is proposed, involving chemo-dissection of permeability barriers which normally surround the individual axons. The findings that acetylcholine, curare, etc. can produce reversible, axonal conduction block in CTMB-treated nerves are not inconsistent with a theory of cholinergic impulse conduction.
Effects of cholesterol and ß-sitosterol in the gerbil
Authors: Gordon Samuel , Stolzenberg Sidney J. , Cekleniak Walter P.
Published: December 2017

The effect of increasing levels (0–1.0%) of dietary cholesterol has been studied in the Mongolian gerbil. A consistent and proportional elevation of serum cholesterol was observed after one week of cholesterol administration. In addition, the simultaneous administration of ß-sitosterol prevented this hypercholesteremia.
Subacute and late cardiovascular sequelae to low doses of gamma radiation
Authors: Smith Durwood J. , Parker Robert C. , Hanna Calvin , Curley Henry E.
Published: December 2017

A battery of in vivo and in vitro tests of cardiovascular performance were used to assess the effects of whole-body gamma radiation (cobalt-60) upon the cardiovascular system of dogs. A new method for study of the pressure-volume relations of isolated surviving arteries is described. Groups of six beagles were exposed to 30 r and 100 r 22 months before death and compared with littermate controls. No differences between irradiated and control dogs could be demonstrated. Eight mongrel dogs received 300 r 30 days before death and were compared with five mongrel controls. The only significant difference observed was in the pressure-volume curves of arteries from irradiated dogs, these vessels having a greater initial tone than control arteries. It is concluded that 30 r and 100 r of whole-body gamma radiation have no demonstrable effect upon the cardiovascular system of dogs irradiated 22 months before study, but that 300 r of gamma radiation does produce a significant abnormality of blood vessels.
Positive pulse reflection in an elastic model from a wider segment with higher resistance
Authors: Hamilton William F. , Brown W. J.
Published: December 2017

It has been shown in earlier work from this laboratory that a standing or resonant wave is set up in the dog's aorta that causes simultaneous augmentation of the systolic pressure in the lower parts of the aorta. It has been hypothesized that this is due to reflection of the pulse wave from the peripheral arterioles. On theoretical premise, the possibility of such reflection has been denied by various authors, on the grounds that the aggregate cross-sectional area of the arterioles is greater than that of the aorta and that reflection in such a region should be negative rather than positive. A model has been constructed of a distensible rubber tube, the end of which can be open or closed with a stopper or a bundle of capillary tubes with aggregate cross-sectional area larger and resistance to flow greater than those of the distensible tube. With tube distended to 20 cm H2O, pulse-wave trains were generated in the tube with the end either open or closed. Pulse waves at the two ends of the tube were recorded simultaneously and recordings showed that with the open tube negative reflection took place, whereas with the tube closed the reflection was unequivocally positive.
Cl36 and Ca45 exchange in atrial fibrillation
Authors: Sekul A. A. , Holland W. C.
Published: December 2017

Transmembrane fluxes of Ca45 and Cl36 have been investigated during treatment with acetylcholine (ACh), rapid stimulation (1200/min.) and ACh induced fibrillation. Resting Ca45 influx was estimated to be 0.024 pmole cm–2sec–1. ACh had no effect. Stimulation for 2 hours increased influx to 0.035 pmole cm–2sec–1. After 2 hours fibrillation influx reached 0.050 pmole cm–2sec–1. The various conditions had no effect on the rate of emergence of Ca45. Absolute Cl36 influx in spontaneously beating preparations was estimated to be 1.74 pmole cm–2sec–1. Stimulation for 20 minutes increased influx to 3.26 pmole cm–2sec–1. After fibrillation (20 min.) influx increased to 4.29 pmole cm–2sec–1. Cl36 efflux in controls was estimated to be 1.61 pmole cm–2sec–1. After 20 minutes stimulation and fibrillation, the values reached 3.09 and 3.05 pmoles cm–2sec–1, respectively. ACh had no effects on either influx or efflux. A comparison of Na, K, Ca and Cl fluxes were made. Data have been interpreted to mean that fibrillation is the result of, or is accompanied by. a marked increase in inward movement of sodium.
Kinetics of erythropoiesis. A comparison of response to anemia induced by phenylhydrazine and by blood loss
Authors: Finch Clement A. , Hanson Mary Lu , Donohue Dennis M.
Published: December 2017

Quantitative measurements of the erythron were made in rabbits. Anemia was produced by red cell removal ( group I), hemolysis from phenylhydrazine ( group II) and red cell removal with replacement by nonviable erythrocytes ( group III). Young red cells, including nucleated and reticulated cell forms, totaled 1.67 x 1010 cells in the normal animal. In anemic animals, by the 3rd day this had increased to 3.59 x 1010 ( group I) and 3.68 ( group II). By the 6th day, average values were 7.24 ( group I) and 7.1 ( group II). There was a greater proportion of young cells in the nucleated form in group I as compared with group II. The addition of nonviable cells ( group III) did not augment erythropoiesis in bled animals. A reticulocyte shift from marrow to circulating blood, proportionate to the degree of anemia, was observed. These studies indicate an augmentation of the rate of erythropoiesis to about three times normal. There was no evidence that products of red cell destruction influence the rate of erythropoiesis.
Factors influencing the ‘resting’ secretion of the adrenal medulla
Authors: Walker William F. , Zileli M. Sherefettin , Reutter Fritz W. , Shoemaker William C. , Moore Francis D.
Published: December 2017

As control observations for the subsequent papers of this series, dogs were subjected to the environmental and experimental conditions to be used in the hemorrhage experiments. These conditions included immobilization, anesthesia, discomfort, tissue trauma and repeated observations of ‘resting secretion.’ The adrenal vein was cannulated so that adrenal vein blood could be collected for analysis in both chronic and acute preparations. Determination of catechol amines in adrenal venous blood and in peripheral venous blood were carried out by the method of Weil, Malherbe and Bone. Total adrenal hormone efflux was calculated as the product of concentration and flow. The results indicate that immobilization alone had little effect on adrenal vein catechol amine output. When immobilization was complicated by excitement and struggling, or when there was pain or discomfort involved, the outputs were increased. Barbiturate anesthesia lowered catechol amine secretion and adrenal vein blood flow very markedly. Tissue trauma, including fracture of the long bones, increased secretion of the catechol amines. It is emphasized that all of these ‘control’ factors must be evaluated in experiments involving measurement of catechol amines in the adrenal venous blood.
Vascular reactions to cold in the cheek pouch of intact and adrenalectomized hamsters
Authors: Wyman Leland C. , Drapeau Lois L.
Published: December 2017

Adrenalectomized golden hamsters unanesthetized or under anesthesia, did not maintain body temperature when exposed to environmental cold (2°C) as well as intact hamsters or adrenalectomized hamsters receiving cortisone replacement therapy. Dial with urethane anesthesia proved unsuitable for studies of microcirculation in cold so light ether anesthesia was used. At room temperature there were no significant changes in caliber of small vessels of intact or adrenalectomized hamsters under ether, but arteries of hamsters receiving replacement therapy constricted. Suitable controls showed that this was partly due to the treatment. During 2 hours in cold air there was significant constriction of arteries of intact and of adrenalectomized hamsters receiving replacement therapy, but no change in veins, while the majority of untreated adrenalectomized hamsters showed no significant changes in the arteries. This is interpreted as an impairment of the normal peripheral vasoconstrictor response to cold which can be restored by replacement therapy.
Substrates supporting activity in immature nerve fibers
Authors: Carpenter F. G.
Published: December 2017

The ‘A’ fibers within mixed nerve trunks from immature chicks (16–21 days incubation) become inexcitable after 2 hours in nutrient-free Ringer's solution. Conduction in the ‘C’ fibers persists up to 8 hours under the same conditions. In contrast, nerves from adult chickens or rats are capable of transmitting impulses up to 14 hours in the same media. Addition of 5 mm/l. glucose or pyruvate rapidly restores conduction; however, there is no restoration when a variety of carbohydrate intermediates are present for 5 hours. Anaerobic survival of conduction with paired nerves is longer in 5 mm/l. glucose than in 10 mm/l. pyruvate and is inversely proportional to the frequency of stimulation. Our findings suggest that: a) a glycolytic energy source in immature axons is available for activity during anaerobiasis; b) the axon membrane is relatively impermeable to certain carbohydrate intermediates; c) in developing nerve the fraction of the total metabolism that is essential for the maintenance of the excitatory state is relatively small.
Afferent pathway of systemic pressor response to proximal vagosympathetic stimulation in the dog
Authors: Kelly William D.
Published: December 2017

The systemic pressor response to stimulation of the cephalic end of the divided vagosympathetic trunk was studied 1–3 weeks after unilateral stellate ganglionectomy and upper thoracic sympathectomy in 14 dogs. In addition, in four of the animals blood flow to the circulatorily isolated head was measured using either the carotid or veterbral arteries alone for perfusion. In response to electrical stimulation of the proximal vagus, blood flow to the head decreased on the average of 21% on the sympathectomized side and by 55% on the intact side. Nevertheless, the average pressor response as measured in the femoral artery was not significantly altered by sympathectomy in either group. The data are interpreted as indicating that the aforementioned pressor response is mediated by way of afferent visceral fibers in the vagus nerve.
Effects of vagosympathetic stimulation on parotid saliva flow in the dog
Authors: Langley L. L. , Smith J. A.
Published: December 2017

Stimulation (15 v., 50/sec.) of the central end of the cut vagosympathetic trunk in the dog causes the expulsion of preformed saliva from the parotid gland. By varying the time, strength and frequency of the stimulus it is possible to alter the rate of secretion. The mechanism responsible for the expulsion of saliva from the gland fatigues under prolonged or repeated stimulation. The latent period of reponse is about 1 second. It is concluded that the sympathetic fibers which run with the vagus nerve in the dog are responsible for the response.
Incorporation of glycine-1-C14 into nucleic acids and proteins of mice with hereditary muscular dystrophy
Authors: Coleman D. L. , Ashworth M. E.
Published: December 2017

The incorporation of glycine-1-C14 into the nucleic acids and proteins of normal and genetically dystrophic mice was studied. Skeletal muscle from adult mice afflicted with muscular dystrophy contained increased amounts of nucleic acids (up to 60% more DNA and 40% more RNA per gram) when compared with muscle from normal littermate controls. No significant differences in nucleic acid concentration of liver, spleen or kidney were seen. Dystrophic skeletal muscle was found to incorporate glycine-1-C14 into both muscle nucleic acids and muscle proteins much more rapidly than normal skeletal muscle. In contrast, the livers from dystrophic animals showed a diminished ability to incorporate this precursor into liver nucleic acids. These differences between normal and dystrophic animals were found to be proportional to the age of the animal, which in turn is proportional to the severity of the disease.
Uterine blood flow and oxygen consumption in pregnant sheep and goats
Authors: Metcalfe James , Romney Seymour L. , Swartwout Joseph R. , Pitcairn Donald M. , Lethin Anton N. , Barron Donald H.
Published: December 2017

This report deals with the volume of maternal blood flow to the pregnant uterus of the sheep and goat. Studies were made in 2 nonpregnant animals and in 20 pregnant animals at known stages of gestation. Measurements of uterine blood flow were made using nitrous oxide according to the Fick principle. The results indicate that in the nonpregnant uterus the blood flow is approximately 25 ml/min. It increases to approximately 200 ml/min. at the 80th day of gestation and exceeds 1000 ml/min. near the end of the 150-day gestation period of these animals. Data are also included for calculation of uterine O2 consumption. The findings with regard to uterine blood flow and O2 consumption are discussed in relation to previous findings in human beings and in rabbits.
Effect of prolonged cold exposure on the gross blood composition of the rat
Authors: Hannon John P. , Young David W.
Published: December 2017

One month's cold exposure (5 ± 1 °C) of male Sprague-Dawley rats induced a slight, but significant, increase in hemoglobin levels but had no effect on the hematocrit. Fasting for 24 hours, although not altering the hemoglobin concentrations of either the control or the cold-exposed animals, did produce a slight lowering of the hematocrit. Cold exposure also resulted in a plasma dilution as indicated by a significant increase in plasma water, and significant decreases in plasma specific gravity and plasma protein levels. Fasting superimposed a further reduction in plasma protein levels under both control and cold-exposed conditions. The levels of blood glucose and total plasma lipids were unaltered by cold exposure but each was significantly reduced by fasting. Significant increases in the nonprotein nitrogen, phospholipid, cholesterol and ketone levels were observed in cold-exposed, nonfasted animals. Superimposed on these changes, fasting produced a decrease in the levels of nonprotein nitrogen and phospholipids and an increase in the level of ketones. It had no effect on the level of cholesterol. Fasting of the cold-exposed animals led to greater reductions in plasma nonprotein nitrogen and phospholipids and a smaller increase in blood ketones as compared to controls.
Hyperosmotic effects on the cat thyroid perfused in vitro
Authors: Boatman Joseph B. , Walsh John M. , Rabinovitz Marvin J.
Published: December 2017

Tissue blocks containing the thyroid gland of cats were perfused via the carotid artery with normal and hypertonic defibrinated bovine whole blood for 2-hour intervals. Details of apparatus and methods for in vitro perfusion are described. Hypertonic perfusion resulted in reduced Na24 and I131 passage into the gland. The rate of in vivo accumulated I131 (inorganic and organic) movement from the gland to the hypertonic perfusate was increased. Tissue sodium and potassium was increased on a dry weight basis and a thyroid weight loss was observed due to loss of water to the hypertonic perfusate. Radiochromatograms of hypertonically perfused glands showed markedly reduced total I131 and synthesis of diiodotyrosine and monoiodotyrosine. It was concluded the thyroid responded to movements of iodide into and out of the cells in a manner that reflected the osmotic state of the external environment.
Incorporation of C14-amino acids into protein of isolated diaphragms: role of the adrenal steroids
Authors: Wool Ira G. , Weinshelbaum Edward I.
Published: December 2017

The incorporation of C14-amino acids into a protein fraction of diaphragms incubated in vitro was measured. Adrenalectomy led to an increase in amino acid incorporation into protein. Cortisone (0.3 mg/day) administered to adrenalectomized rats tended to restore incorporation to normal; desoxycorticosterone (0.06 mg/day) was without effect. Larger doses of cortisone (1 or 2 mg/day) produced a marked reduction in amino acid incorporation into diaphragms from both normal and adrenalectomized rats. Fasting reduced histidine incorporation into muscle protein whether the donor rat was normal or adrenalectomized. Phenylalanine-3-C14 incorporation into diaphragm protein was measured at several phenylalanine concentrations. Despite large (100-fold) changes in the phenylalanine pool size the percentage increase in C14 incorporation after adrenalectomy was similar.
Effect of spontaneous activity on afferent response in the MES auditory cortex of the dog
Authors: Tunturi Archie R.
Published: December 2017

Treating the spontaneous electrical activity (SEA) and the evoked potential due to a p pulse at the MES auditory cortex as random variables at 3-msec. epochs, an increase in standard deviation during the evoked potential was found suggesting the occurrence of two statistical processes. By suitable application of cocaine hydrochloride locally to the cortex, it was possible to suppress the standard deviation of SEA and obtain a potential with no or little variance. This potential was defined as the ‘afferent response’ representing the activity due to volleys from the ear. It was concluded that the locally arising SEA has connections to the nerve elements causing the afferent response, thus producing the variance of the evoked potential. The SEA, therefore, is an information destroying process, since it reduces the detectability of response from stimulation of the ear.
Role of the non-Newtonian behavior of blood in hemodynamics
Authors: Haynes Robert H. , Burton Alan C.
Published: December 2017

The role of the non-Newtonian behavior of blood in perfused vascular beds has been assessed by measuring the pressure-flow curves of erythrocyte suspensions with hematocrits from 9 to 85%, in glass tubes of radii from 50 to 800 µ. The curves become linear as the flow increases, and for each tube, point back to a ‘nodal point’ on the negative flow axis which is independent of hematocrit. From this data, curves of the rate of shear versus shearing stress at the wall (consistency curves) were obtained which are all linear at stresses greater than 20 dynes/cm. The wall shearing stress in all categories of blood vessels is greater than this, especially in the arterioles where it is 200 dynes/cm. It is concluded that in perfused vascular beds the flow properties of blood are essentially linear in the physiological working range so that the distensibility of the vessels is the all important factor in determining the shape of the pressure-flow curves.