bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparison of the Effects of Three Organic Solvents: Dimethyl Sulfoxide, Formamide, and Propylene Glycol, on Spontaneous Activity of Isolated Smooth Muscle
Authors: Bonnardeaux J. L.
Published: April 2011

The effects of propylene glycol, formamide, and dimethyl sulfoxide on the contractility of isolated smooth muscle preparations of uterus, duodenum, and rectum were studied. The recording technique employed provided information about the effects of the compounds on the frequency and amplitude of contractions of two types of waves. All three compounds depressed the amplitude of the contractions. In the case of dimethyl sulfoxide, this action can be attributed to metabolic changes. The changes produced in frequency of contraction of duodenum could be attributed to direct membrane phenomena and changes induced through a nervous interaction. In the case of the uterus and rectum, the membrane mechanisms seemed to be either directly affected or secondary to metabolic action. It is concluded that these agents are not pharmacologically inert since they possess pharmacological properties of their own.
Response of Caudal Photoreceptor of Crayfish to Continuous and Intermittent Photic Stimulation
Authors: Galeano C. , Chow K. L.
Published: April 2011

The response of the caudal photoreceptor of the crayfish to steady and intermittent photic stimulation was studied, with particular reference to decrement during prolonged stimulation.The same duration of photostimulation was applied in two patterns, continuous and intermittent, and the intensity of the light was kept constant throughout both patterns. At points with the same duration and intensity of stimulation, the decrement was greater when the receptor was driven with intermittent stimulation, within a certain repetition rate. After the response to repetitive short stimulation had waned, spontaneous restoration occurred during resting periods in the dark. A novel photostimuli intercalated into an intermittent photostimulation series did not restore the responsiveness to the previous level. The electrical stimulation of nerves from the telson and uropods, eliciting inhibition of discharge from the photoreceptors, diminished the photoresponses as it was applied; it increased the photoresponses coincidently with the period of postinhibitory rebound after its cessation.It is difficult at present to account for these complex adaptational properties, which suggest either an unusual photoreceptive process or a form of neural plasticity.
The Pre- to Post-capillary Resistance Ratio in the Human Forearm
Authors: Newberry P. D. , Hayman G. A. , Parsons S.
Published: April 2011

A plethysmograph made of two rubber bladders, enclosed in a sleeve of thin brass sheet, was used to measure capillary filtration rate [Formula: see text] in the forearms of five supine subjects at a room temperature of 27 ± 1 °C, at several plethysmograph pressures (pPL) between 0 and 25 mm Hg while venous pressure (pV) was held constant. We (Newberry et al. 1970) reported previously that in the same five subjects [Formula: see text] increased linearly with pV at a mean rate of 0.00357 ml/min∙100 ml∙mm Hg. [Formula: see text] decreased linearly with pPL in each subject (r varied from −0.81 to −0.99) at a mean rate of −0.00538 ml/min∙100 ml∙mm Hg. Compared as paired values the absolute values of these rates are significantly different (p < 0.02). It is shown that the pre- to post-capillary resistance ratio (rA:rV) can be determined from the relationship between the rates of change of [Formula: see text] with change of pV and pPL. The mean value of this ratio was 2:1 with a range from 1.03:1 to 3.5:1. It is likely that the absolute value of [Formula: see text]/ΔpPL is the capillary filtration coefficient.
Sequential Lowering and Raising of Brain γ-Aminobutyric Acid Levels by Isonicotinic Acid Hydrazide
Authors: Wood J. D. , Peesker S. J.
Published: April 2011

The intramuscular administration of isonicotinic acid hydrazide to chicks produced initially a rapid and significant decrease in the concentration of brain γ-aminobutyric acid (GABA) which was followed by a reversal of the effect such that the GABA level became greater than that in untreated control chicks.
Characteristics of Pacemaker Oscillations in Aplysia Neurons
Authors: Mathieu P. A. , Roberge F. A.
Published: April 2011

Slow membrane potential oscillations of 5–50 mV in amplitude were unmasked in "bursting" neurons of Aplysia, following treatment with tetrodotoxin. These oscillations were sensitive to changes in membrane polarization; both the amplitude and period decreased with depolarization and increased with hyperpolarization. The oscillations could be blocked by strong depolarization or hyperpolarization, and the two critical levels or stable states corresponded approximately to −30 mV and −70 mV. The bursting discharge of the intact neuron appears to be caused by such an oscillation, but the effects of spike activity on the oscillator mechanism are still largely unknown.
The Extracellular Space of the Single Fiber from the Giant Barnacle
Authors: Brigden M. L. , Spira A. W. , Hinke J. A. M.
Published: April 2011

Reexamination of the extracellular space of single fibers from Balanus nubilus using light and electron microscopy reveals it to be an elaborate system of clefts and tubules which permeate the fiber substance so that a position in the myoplasm is never more than 2 μ from extracellular fluid. Penetration by ferritin and horseradish peroxidase particles indicate patency of the tubular system as far as the sarcoplasmic reticulum. Both radioautographic and classic influx studies using 22Na+ indicate that the Na+ in the extracellular compartment, like the Na+ in the bath, has a diffusion coefficient of 1.28 × 10−5 cm2/s at 25 °C and a half-time exchange [Formula: see text] of about 1 min. Even though the extracellular space contains half the fiber Na+ in 6% of the fiber volume, it can be cleared of Na+ after 6 min in a zero NaCl bath without significant alteration to the intracellular Na+ content.
The Beneficial Effects of Postirradiation Treatment with Cobaltous Chloride on the Development of Nuclear Damage in Thymocytes, Erythropoiesis, and the Survival of Mice
Authors: Vittorio P. V. , Whitfield J. F.
Published: April 2011

Cobaltous chloride injected subcutaneously into mice immediately after irradiation decreases the number of cells with pyknotic nuclei appearing in the lymphocyte population of the thymus. In vitro studies show that the presence of cobaltous chloride in the incubating medium immediately after irradiation again lowers the subsequent appearance of cells with pyknotic nuclei. A subcutaneous injection of cobaltous chloride into mice immediately after irradiation also increases both erythropoietic recovery (as measured by the incorporation of 59Fe into blood and spleen) and survival.
Carnitine Enhances the Effect of Norepinephrine on Oxygen Consumption in Rats and Mice
Authors: Hahn Peter , Skala Josef , Davies Peter
Published: April 2011

In adult rats and mice the rise in oxygen consumption due to the subcutaneous injection of norepinephrine is doubled if carnitine (6 or 10 mg/100 g) is also injected.
Effects of Propranolol on Several Physiological Responses During Orthostatic and Exercise Stress in Healthy Male Subjects
Authors: Maksud Michael G. , Tristani Felix E. , Coutts Kenneth D. , Barboriak Joseph J. , Hamilton Lyle H.
Published: April 2011

The effects of propranolol administration on several responses to orthostatic and exercise stress were examined in 16 healthy young men. Propranolol treatment resulted in a significantly lower heart rate response to orthostatic stress, while systolic and diastolic blood pressures were unaffected by the drug. Propranolol treatment resulted in a significant reduction in heart rate and minute ventilation during bicycle exercise. However, oxygen consumption and mean exercise endurance times were not significantly altered following propranolol treatment. The findings suggest that in healthy young male subjects the cardiac depressant effects of propranolol are compensated for, so that the oxygen uptake and work capacity are not seriously compromised.
Rheological Properties of Blood from Diabetic Wistar Rats
Authors: Zingg Walter , Wilson R. B. , Morgan C. D. , Anderson D. E.
Published: April 2011

The rheological properties of blood from rats made diabetic by subtotal pancreatectomy or alloxan injection were compared with those of blood from normal Wistar rats. Blood viscosity, plasma viscosity, hematocrit, erythrocyte sedimentation rate, plasma osmolality, and serum glucose were measured. The alloxan-treated rats had a significantly higher blood viscosity than the normal rats. The plasma viscosity remained unchanged.
Fluid and Electrolyte Shifts Relating Cardiac Hypertrophy with Normal Growth
Authors: Horwood Dorothy M. , Beznak Margaret
Published: April 2011

Fluid shifts and electrolyte changes were studied in skeletal muscle and in myocardium of normal male rats weighing 150–450 g and in rats with cardiac hypertrophy experimentally produced by subdiaphragmal aortic constriction. Extracellular fluid volume was measured by means of 35S-sulfate and was found to increase in all parts of the heart and in skeletal muscle as rats grew from 150 to 300 g. Maximal values for sulfate space were reached in the 250–300 g group and then they decreased as the rats continued to grow from 300 to 450 g. Significant increases (p < 0.05) in sulfate space and sodium concentration of the left and right ventricles were found to occur within 24 h after aortic constriction whereas a significant increase in cardiac mass (p < 0.05) occurred only after 2 days. The increases became very pronounced (p < 0.001) by 10 days, after which both sulfate space and electrolyte concentration returned to within the normal range. Since these transient increases in sulfate space occur prior to and during very rapid growth in both normal muscle and following aortic constriction, a relationship is suggested.
The Chloride Conductance and its pH Sensitivity in Insect Muscle
Authors: Washio H.
Published: April 2011

The effects of the replacement of chloride with methyl sulfate and of changes in the pH of the extracellular solution on the membrane conductance of locust leg muscle fibers were studied with intracellular electrodes. The contribution of chloride to the membrane conductance varied with the extracellular pH. The membrane conductance was sensitive to change in pH in the standard (chloride) saline, being high in alkaline solution and low in acid solution. However, after replacement of chloride by methyl sulfate the membrane conductance showed little change when pH was altered. It was concluded that chloride ions are mainly concerned in the pH sensitivity of the resting conductance.
γ-Aminobutyric Acid and a Caudato-Nigral Inhibition
Authors: Feltz Paul
Published: April 2011

An extracellular microiontophoretic study was made in cats of nigral neurones shown to be inhibited by caudate stimulation. A strong depressant effect was obtained with γ-aminobutyric acid but not with glycine, acetylcholine, or dopamine.
RNA Content and Protein Synthesis in Skeletal Muscles of Young Rats: Effects of Protein Deficiency
Authors: Howarth R. E.
Published: April 2011

A protein-free diet was fed to weanling rats for 1, 2, 3, 4, or 7 days before sacrifice in order to determine the time course of RNA depletion from their gastrocnemius muscles. A 34% loss of total RNA occurred on the first 2 days and thereafter depletion occurred at approximately 8% per day. The time course of RNA repletion was determined by refeeding a stock diet to protein-starved rats. A significant increase in total RNA content occurred on the 2nd day and repletion of total RNA content was complete on the 4th day of refeeding the stock diet. Rates of muscle protein synthesis in vivo were estimated by 14C incorporation from L-leucine into muscle proteins, and correlations between RNA concentrations and rate of protein synthesis were evaluated by linear regression anlysis. There was no significant relationship between soluble RNA concentration and protein synthesis. The relationship between protein synthesis and microsomal RNA concentration was significant. The results support the conclusion that availability of ribosomal RNA is a major factor in the long-term regulation of muscle protein biosynthesis.
Effect of Changes in the Osmolality of the Luminal Fluid on Intracellular Concentration of Solutes in the Hamster Jejunum
Authors: Dinda P. K. , Beck Marjorie , Beck Ivan T.
Published: April 2011

Paired experiments were performed in vitro using two adjacent segments of hamster jejunum. The intracellular Na, K, glucose, and water concentrations of the segment incubated in isotonic solution on the mucosal side (mucosal solution) (control) were compared to the intracellular concentrations of the same solutes and water in the segment incubated in hypo- or hypertonic mucosal solutions (experimental). The solution bathing the serosal side (serosal solution) was always isotonic and remained so throughout the experimental period of 45 min. Results indicate that hypotonicity of the mucosal solution significantly increased the total and intracellular water content of the intestine. Intracellular Na, K, and glucose concentrations significantly decreased, while, except for glucose, the intracellular solute content remained unaltered. Hyperosmolality of the mucosal solution, on the other hand, decreased the total and intracellular water content, with an increase in the concentration of all intracellular solutes. The intracellular solute content, however, did not change. Calculation of the data shows that the approximate total intracellular solute concentration (2Na+ + 2K+ + glucose) increases linearly with the increase in osmolality of the mucosal solution. The approximate total intracellular solute concentration was always higher than that of the mucosal solution. In muscle tissue, all of the K+ but only 30% of the Na is osmotically active. If this percentage of free Na+ is applied to the epithelial cell, our calculations indicate that the intracellular fluid of the intestinal cell became approximately isoosmotic with the mucosal solutions used. This osmotic equilibrium between the mucosal solution and the epithelial cell may be a prerequisite for the isoosmotic transport of fluid across the intestinal wall.
The Measurement of Potassium Efflux in Superfused Frog Sartorius Muscles
Authors: Lucier G. E. , Mainwood G. W.
Published: April 2011

A method of measuring net potassium flux in isolated frog sartorius muscles is described. The method depends on superfusing muscles at a slow rate in a gas phase so that a thin film of fluid is maintained on the surface. The effluent is analyzed and efflux determined by the product of flow rate and concentration change. Compartment volumes are measured and water movement is monitored by 14C-inulin. A mean resting net efflux of 25 nequiv/g/min or 0.9 pequiv/cm2/s is given in Ringers containing 2.5 mequiv/l potassium. Diffusion limits the response time of the system so that it is only possible to estimate mean flux rates over intervals of the order of 10–20 min. The minimum detectable change in potassium content of the muscle with this system is about 3.5 nequiv or approximately 0.04% of the average potassium content of the sartorius muscle. The increase in net efflux measured during activity (3.7 pequiv/cm2 per impulse) represents only about half the expected value. This is probably due to reentry of potassium with the electrochemical gradient resulting from the increased extracellular concentration. The addition of ouabain to the superfusion fluid results in an increase of potassium efflux to about four times the resting level (85 nequiv/g/min).
Inhibition of Mouse Ascites Tumors by Carbohydrate Combined with Immunization
Authors: Eng C. P. , Bhatnagar M. K. , Morgan J. F.
Published: April 2011

Mice, inoculated intraperitoneally with TA3 ascites tumor cells, received intraperitoneal injections of D-mannose, D-glucosamine, 2-deoxy-D-glucose, and DL-glyceraldehyde. With daily single injections for 10 days, D-mannose produced no effect; D-glucosamine reduced the total tumor volume but not the packed cell volume; 2-deoxy-D-glucose caused a moderate reduction in both the tumor fluid and the packed cell volume; and DL-glyceraldehyde reduced the tumor development drastically. With multiple injections on a single day, 2-deoxy-D-glucose produced no effect; D-glucosamine caused a moderate inhibition of tumor growth; and DL-glyceraldehyde strongly inhibited the tumor development. The inhibitory effect of DL-glyceraldehyde was greatly enhanced by the previous immunization of the mice with an insoluble fraction prepared from the tumor cells. The potentiating effect of DL-glyceraldehyde and immunization was found also with the Ehrlich, Ehrlich-Lettré, 6C3HED, and SAI mouse ascites tumors. DL-Glyceraldehyde was toxic to mice with an LD50 of 3.0 g/kg. Mice, injected intraperitoneally with 1.0% DL-glyceraldehyde solution, developed enlarged livers which showed excessive amounts of cytoplasmic glycoprotein granules.
Contralateral Natriuresis During Reduced Renal Artery Perfusion Pressure in "Renin-Depleted" Dogs
Authors: Belleau L. J. , Mailhot D.
Published: April 2011

The mechanism of contralateral natriuresis subsequent to reduction of renal perfusion pressure was studied. In control dogs a drop in the renal perfusion pressure caused a very significant increase in the arterial and renal venous plasma renin activity, as well as a significant contralateral natriuresis. Systemic blood pressure increased along with contralateral intrarenal resistance. Glomerular filtration rate and renal blood flow did not change in the opposite kidney.In "renin-depleted" dogs a comparable drop in the renal perfusion pressure failed to stimulate renal venous and arterial plasma renin activity. Contralateral natriuresis increased significantly as well as the systemic blood pressure. In the absence of renin, intrarenal resistance of the opposite kidney did not change. Contralateral glomerular filtration rate and renal blood flow remained unchanged.During reduction of renal perfusion pressure, the most significant findings were: (1) absence of renin release despite the stimulation in renin-depleted dogs, (2) increase in contralateral resistance explained by the renin–angiotensin system, (3) systemic blood pressure increment despite renin release inhibition, and (4) the renin–angiotensin system not directly responsible for the contralateral natriuresis following a reduction in the renal perfusion pressure.Contralateral natriuresis cannot be explained by changes in glomerular filtration, renal blood flow, or intrarenal resistance. It is suggested that the rise in blood pressure or another factor, possibly neural or humoral, could explain the contralateral natriuresis.
Cation Transport by Slices from the Isolated Perfused Rat Liver
Authors: Nestruck A. C. , Furneaux R. W.
Published: April 2011

Isolated livers from fed rats were perfused for 1 h with a medium consisting of Krebs–Ringer bicarbonate buffer with added albumin and glucose. Rates of perfusate and bile flow, differences in [Formula: see text], [Formula: see text], and pH, and glucose and potassium efflux were measured. Rewarmed slices of liver taken before the surgical preparation and before the perfusion were found to be able to reverse a cation shift imposed by cold incubation. Slices of liver taken after one perfusion were not able to effect this expected cation transport. It is proposed that the perfusate used was not ideal as evidenced by the altered membrane function of slices after perfusion.
Presynaptic Action of Central Depressant Drugs: Inhibition of Depolarization–Secretion Coupling
Authors: Quastel D. M. J. , Hackett J. T. , Okamoto K.
Published: April 2011

Chlorpromazine, like raised osmotic pressure, not only increases spontaneous miniature endplate potential frequency (F) in mouse diaphragm (in vitro) but also depresses the slope of log F versus focal presynaptic depolarization. It also depresses the slope of log F versus [Ca], in raised K+ (constant depolarization). Similar effects are seen with pentobarbital, chloral hydrate, chloroform, and lowered pH. The drugs have similar actions in locust muscle, where the transmitter is not acetylcholine.
Calcium and Contraction in the Rabbit Anterior Mesenteric–Portal Vein
Authors: Collins G. A. , Sutter M. C. , Teiser J. C.
Published: April 2011

Studies were done measuring contractile activity in the isolated rabbit anterior mesenteric–portal vein (A.M.V.). The rabbit A.M.V. requires external calcium for both spontaneous activity and the initiation and maintenance of contractions to agonists.After bathing the tissues in calcium-free Krebs' solution containing 1 mM ethyleneglycoltetraacetic acid (EGTA) for 10 min, and then washing out the EGTA, the re-addition of calcium produced a contraction. The pre-addition of a small amount of calcium (0.1 mM) after EGTA treatment (while not inducing a contractile response) alters subsequent contractile responses to larger concentrations of calcium. This is interpreted as the ability of membrane-bound calcium to control membrane permeability to calcium.Other experiments involved bathing the tissues in calcium-free solution until no response was obtained to agonists, and then re-adding calcium. The time course of the responses to noradrenaline after calcium re-addition depended on the length of calcium incubation. This suggests that noradrenaline can release a loosely bound calcium fraction which may be involved in controlling calcium influx. This bound calcium, however, does not provide a major source of activator calcium in normal Krebs' solution.
Thyrotropin (TSH) Response to Synthetic TSH-Releasing Factor Following Pharmacological Blockade of Adrenocorticotropin (ACTH) Secretion
Authors: Koch Bernard , Jobin Michel , Dulac Serge , Fortier Claude
Published: April 2011

Pretreatment of rats with either dexamethasone or chlorpromazine, morphine, and Nembutal, though completely preventing the rise in plasma corticosterone and hence the release of ACTH otherwise associated with the intravenous injection of either saline or synthetic TSH-releasing factor (TRF) (200 ng), under ether or Nembutal anesthesia, failed to alter the plasma TSH response to TRF recorded 10 min after the injection. The plasma corticosterone response to the stress of the intravenous injection was of the same order in the animals injected with TRF as in the saline-injected controls. These findings fail to support the hypothesis of a competition between ACTH and TSH secretion at the pituitary level.
Detection of Organelles in Myelinated Nerve Fibers by Dark-Field Microscopy
Authors: Smith R. S.
Published: April 2011

Dark-field microscopy improves the optical detection of intraaxonal organelles. In living myelinated nerve fibers of the adult rat and the adult toad, fast (approximately 1 μm/s) somatopetal and somatofugal movement of near-spherical particles was seen. Rod-shaped organelles were also detected in nerve fibers from both the rat and the toad, but these organelles showed no axial motion.
Stimulation of Renal Organic Base Transport by Uranyl Nitrate
Authors: Hirsch G. H.
Published: April 2011

Administration of 6 mg/kg uranyl nitrate to adult male rats resulted in a significant enhancement of N-methylnicotinamide (NMN) uptake by renal cortical slices when measured 24 or 48 h after injection. The accumulation of another organic base, tetraethylammonium (TEA), by renal cortical slices was also significantly increased by uranyl nitrate treatment, but transport of the organic acid p-aminohippurate (PAH) was not altered in these experiments. The kidney weight to body weight ratio was increased in treated rats. Accumulation of NMN by renal cortical slices was significantly enhanced within 8 h after administration of 6 mg/kg uranyl nitrate. NMN uptake was also significantly enhanced 24 and 48 h after administration of 0.5 or 1.0 mg/kg uranyl nitrate to rats. The nephrotoxicity produced by uranyl nitrate was not directly related to its induction of organic base transport. The data support the hypothesis that the organic base transport system can be selectively induced by appropriate stimuli. Treatment of rats with potassium chloride did not enhance NMN uptake by renal cortical slices.
Separation of Pancreatic and Gut Glucagon-Like Immunoreactivity (G.L.I.) with Observations on Plasma Concentrations of these Hormones during Lactation
Authors: Manns J. G.
Published: April 2011

A method is described for the separation of plasma, pancreatic, and gut G.L.I. by selectively extracting glucagon into aqueous acetone and then precipitating it with additional acetone. Results using this technique indicate that the specificity is satisfactory and that proteolytic enzymes and other proteins are essentially quantitatively removed. Using this technique, it is shown that total plasma G.L.I. increases very substantially in the initial stages of lactation, whereas the plasma extracts representing primarily pancreatic glucagon increase only slightly.
Effects of Dopamine and Other Catecholamines on the Splanchnic Circulation
Authors: Shanbour Linda L. , Parker Don
Published: April 2011

Studies were conducted to evaluate the effects of dopamine (3, 4-dihydroxyphenylethylamine) and other catecholamines on the mesenteric vascular bed in dogs. Mesenteric and hepatic artery blood flows were measured with electromagnetic blood flow transducers. Catecholamines were infused intra-arterially into a branch-of the mesenteric artery. Dopamine consistently decreased mesenteric and hepatic artery blood flows at all dose levels studied (5–100 mg/kg). Phenoxybenzamine (12.5 mg/kg) blocked the effects of norepinephrine (0.05–1.0 μg/kg) and reversed the responses to dopamine in the mesenteric bed to those of pure vasodilation (no transient constriction was observed) but failed to abolish the constrictor action of dopamine on the hepatic artery. Propranolol or haloperidol, when administered with the phenoxybenzamine, did not attenuate the mesenteric responses to dopamine. Haloperidol prevented the hepatic artery vasoconstriction produced by dopamine but did not alter isoproterenol-induced hepatic artery vasodilation. No competitive action was observed between dopamine and norepinephrine or isoproterenol. These results suggest that (1) dopamine produces selective vasodilation of the mesenteric bed which is not blocked by haloperidol, and (2) dopamine has a unique action on the hepatic vascular bed which is blocked by haloperidol.
Increased Depletion of Catecholamines by Reserpine in Immature Cats
Authors: Davidson W. J. , Innes I. R.
Published: April 2011

Catecholamine contents of heart and spleen of young cats were significantly less than those of adult cats 24 h after intraperitoneal injection of reserpine, 1 mg/kg, although the catecholamine contents of those organs in untreated cats were not significantly different between young and adult cats.
Purified Growth Hormone Releasing Factor Increases 45Ca Uptake into Pituitary Cells
Authors: Milligan J. V. , Kraicer Jacob , Fawcett C. P. , Illner Pavel
Published: April 2011

A purified extract of sheep hypothalamus possessing growth hormone releasing factor activity caused an increased uptake of 45Ca from the incubation medium into the rat adenohypophysis concurrent with an increased release of growth hormone. The data are consistent with the "stimulussecretion coupling" model proposed for the release of preformed hormone from the adenohypophysis.
Amino Acids in the Cobalt-Induced Epileptogenic and Nonepileptogenic Cat's Cortex
Authors: Koyama Ikuko
Published: April 2011

Epileptogenic cortical foci were produced by the topical application of cobalt powder to the exposed anterior or posterior sigmoid gyrus of adult cats. Within 60–90 min after application, epileptic discharges were observed only in the area adjacent to the cobalt-treated region (focus). Twenty-four hours later, tonic and clonic epileptic convulsions occurred. These seizures disappeared by the 3rd day after treatment. The concentration of amino acids in the cortex was determined during three periods after the application of cobalt: preconvulsive period (acute), 0–360 min; convulsive period (semi-acute), 24–48 h; postconvulsive period (chronic), 30–70 days.In the cortical tissue adjacent to the site of cobalt application, glutamic acid, aspartic acid, and γ-aminobutyric acid were decreased, while there was a marked increase in glycine, threonine, serine, and taurine during the convulsive period. In the preconvulsive period, the amino acids in the superfusates of the cobalt-treated cortex were measured. The rate of release of glutamic acid increased within 90 min after cobalt application together with a corresponding decrease of the rate of release of glutamine and urea. The excitatory effect of the liberated glutamic acid may play an important role in the production of focal epileptic discharges following the application of cobalt powder to the cerebral cortex.
The Effect of Acetylsalicylic Acid, Caffeine, and Codeine on the Excretion of Phenacetin Metabolites
Authors: Gault M. Henry , Shahidi Nasrollah T. , Gabe Alec
Published: April 2011

The urinary excretion of total N-acetyl-p-aminophenol and conjugates (NAPA) and total 2-hydroxyphenetidin and conjugates (2-OHP) was studied after ingestion of 2 g phenacetin alone and also in combination with acetylsalicylic acid, caffeine, and codeine (APC and C). NAPA excretion was measured in 17 patients; seven had taken the combination analgesic preparation in large amounts for 5 or more years and 11 had values for creatinine clearance of < 50 ml/min. NAPA excretion was measured for 96 h after drug ingestion and 2-OHP for at least 24 h in 15 patients of the same group. Excretion of total NAPA and 2-OHP was significantly reduced when phenacetin was ingested as APC and C compared with excretion when phenacetin was given alone. In the presence of renal failure NAPA excretion was merely delayed, whereas 2-OHP excretion was reduced or absent.
Sarcoplasmic Resistivity of Normal and Dystrophic Muscle Fibers of Mice
Authors: Gradmann Dietrich
Published: April 2011

The electrical resistance of normal glass microelectrodes was calibrated against surrounding solutions of different resistivities. At 10−8 A A.C. (1 kHz) the voltage drop across the KCl-calibrated electrode, inserted into muscle fibers, gives some indication of the cytoplasmic resistivity r. The means ± standard error in units of Ω centimeters yielded for normal and dystrophic M. gastrocnemius 138 ± 4 and 125 ± 6, and for normal and dystrophic M. soleus 166 ± 8 and 135 ± 4. The r values of maximal probability are 18–34 Ω cm lower. These r values are higher than rh, the resistivity expected from the ion content in homogeneous distribution. On the basis of Maxwell's equation for the resistivity of suspensions, this result, as well as the dystrophic fibers' lower r value, may be explained if one assumes a higher degree of inhomogeneity of ion distribution in the normal muscle fiber.
Urine Pigments after Ingestion of Phenacetin
Authors: Gault M. H. , Shahidi N. T.
Published: April 2011

Pigments occurring in urine of patients who had ingested analgesics containing phenacetin were studied by several methods including gel filtration and paper chromatography. Pigmentation usually developed several hours after urine was voided. It first became red–brown and, later, brown–black. Excretion of pigment precursors was ordinarily complete within 7 h of drug ingestion, but took longer when renal function was impaired. The rate of pigment development in vitro was highly sensitive to temperature, time, and the addition of sulfatase. Derivatives of aromatic amines, e.g. 2-hydroxyphenetidin sulfate, contribute to the pigmentation.
Distribution of Thermosensitive and Nonthermosensitive Preoptic and Anterior Hypothalamic Neurons in Unanesthetized Cats, and Effects of Some Anesthetics
Authors: Jell Ralph M. , Gloor Pierre
Published: April 2011

Preoptic and anterior hypothalamic neurons were studied with extracellular microelectrodes in partially decerebrated unanesthetized cats. Local temperature was varied using implanted, water-perfused thermodes, and cell responses were classified according to firing rate change during warming and cooling, and according to anatomical localization. One hundred seventy-five cells were tested in 17 cats. Most cells were located in the medial preoptic area and the adjacent area of the diagonal band of Broca, with an apparent scarcity of cells outside these areas. Five distinct classes of thermosensitive cells were observed, together with a population of nonthermosensitive cells. These five classes were: type A cell showing a linear relationship between firing rate and temperature; type B, response varying during period of observation; type C, showing thermosensitivity above or below a certain threshold; type D, having time lag of lead between temperature change and change of firing rate; type E, firing maximally over a certain temperature range with decreased rate above and below that range. Four anesthetic agents (ether, chloralose, sodium thiopental, and sodium methohexital) were applied during the study of 30 cells, and depression of spontaneous firing rate was observed in all cases with moderate dosages. Eighteen cells showed an increase in Q10 during the action of the drug, 10 showed no change, and two showed a decreased Q10.
Glucosinolates and Their Hydrolytic Products in Intestinal Contents, Feces, Blood, and Urine of Rats Dosed With Rapeseed Meals
Authors: Lo M. T. , Hill D. C.
Published: April 2011

Rapeseed meals were prepared from B. napus rapeseed, either from seed previously heated in boiling water for 10 min or from unheated seed. Rats were dosed by stomach tube with 1 g of each meal and urine was collected for periods of 8,16, 24, and 36 h. Representative rats were sacrificed at these times and total gastrointestinal contents plus feces and total blood were collected. All samples, including the meals, were subjected to analyses for isothiocyanates, nitriles (BCN), and goitrin (OZT), both with and without myrosinase treatment. Significant amounts of glucosinolates were absorbed and excreted intact in the urine. The heated meal yielded more BCN and OZT in the urine than did the raw meal. At 8 h considerable amounts of OZT were found in the blood of rats dosed with heated meal. No free isothiocyanates were found in any of the samples examined. However, following dosing with heated meal, urine treated with myrosinase yielded isothiocyanates equivalent to 40% of their parent glucosinolates present in the meal. Evidence suggests that when heated or raw meals are ingested the main toxic substances formed are BCN and OZT, the former predominating in the case of raw meal and the latter in the case of heated meal.
Activités de la HL-STH hypothalamique, de la STH hypophysaire et de la STH mimétique du plasma chez des rates adultes et immatures traitées à l'Enovid
Authors: Brazeau Jr. P. , Saucier R. , Husain S. M.
Published: April 2011

The chronic administration of norethynodrel–mestranol to both mature and immature rats leads to an increase in hypophysial STH content. Our results suggest that this increase in STH content results from a decrease in the secretion of STH-RF or an increase in the secretion of STH-IF. The decrease in plasma STH-like activity would reflect this inhibition in STH-RF secretion. This is re-fleeted finally in retarded osteogenesis and growth.
Physicochemical Properties of Some Semisynthetic Penicillins
Authors: Rollo Ian M.
Published: April 2011

Variation in the structure of the sidechain of penicillins has been shown to be associated with changes in the physicochemical properties of the substances. Values obtained for ionization constants, oleyl alcohol/water partition coefficients, and binding to serum albumin in a series of 10 semisynthetic penicillins varied from 2.78 to 5.41, from 0.87 to > 800, and from 29% to 100%, respectively. The partition coefficient appears to be the most important of these parameters. Decrease in acid strength is due probably to the formation of dimers by highly nonpolar penicillins. Increase in extent of binding to albumin has been shown previously to be due to increase in hydrophobic bonding between highly nonpolar penicillins and the protein surface. Our data support this. In certain cases, the formation of reinforced ionic bonds may supplement nonionic bonding.
The Resistance to Blood Flow in the Capillaries
Authors: Jay A. W. L. , Rowlands S. , Skibo L.
Published: April 2011

The pressure–flow relations of single erythrocytes and of heparinized whole blood flowing through glass tubes 4–15 μm in diameter have been studied. Driving pressures ranging from 0 to 8 cm H2O were used to produce mean velocities of flow of 0–1000 μm∙s−1. The velocities were measured by high-speed cinemicrophotography. The velocities of latex microspheres suspended in water and in plasma were also measured. By comparing the mean flow velocities of erythrocytes with that of microspheres in water, values for the apparent relative viscosity were obtained.Results show that the pressure–velocity relationship in each case is linear. The relative viscosity of plasma ranged from 1.50 to 2.25 which agrees with values obtained by other methods of viscometry. A single erythrocyte flowing through the tubes increases the flow resistance and the apparent viscosity by about 30% over that of the suspending medium alone. The percentage increase is the same using plasma or Ringer solution as the suspending fluid. The apparent viscosity of whole blood even at hematocrits of over 80% is only about 55% higher than the viscosity of plasma.
Role of the Gastric Pacesetter Potential Defined by Electrical Pacing
Authors: Kelly Keith A. , Force Richard C. La
Published: April 2011

This experiment substantiates the hypothesis that the gastric pacesetter potential sets the pace of gastric contractions. By pacing the gastric pacesetter potential with electrical stimuli during periods of spontaneous and pentagastrin-induced contractile activity, we also paced gastric contractions.
The Effect of Injecting an Inert Oil Into the Cerebral Ventricular System Upon Fever Produced by Intravenous Leucocyte Pyrogen
Authors: Cooper K. E. , Veale W. L.
Published: April 2011

An injection of paraffin oil into the lateral cerebral ventricle of afebrile rabbits appears to fill the entire ventricular system. Such an injection does not affect body temperature nor does it alter the time elapsing between an intravenous injection of leucocyte pyrogen and the fever which follows. It does, however, greatly increase the height and duration of the fever. Oil injected into the cerebral ventricles of rabbits during an intravenous infusion of pyrogen in an amount previously shown to maintain a steady fever level causes the body temperature to commence to climb again and continue to climb considerably thereafter. We suggest that these experiments indicate that leucocyte pyrogen, reaching the hypothalamus via the blood stream, may be excreted through the ependyma of the third ventricle into the cerebrospinal fluid, or that substances released as a result of the presence of leucocyte pyrogen in brain tissue may be thus excreted.
Some Metabolic Effects of a Single Dose of Crystalline Dihydrotachysterol
Authors: Garrett R. J. Burriss , Bickley Harmon C. , Little J. W.
Published: April 2011

A single 1 mg dose of crystalline dihydrotachysterol was administered by gavage to female rats. Quantitative studies of subsequent changes in serum calcium level, food intake, animal weight, and femur cortical fragility indicated that the effects of this drug were severe and protracted. Serum calcium concentration increased to a peak within 2 days and remained elevated throughout the experiment. Food intake and weight of dihydrotachysterol-treated animals declined severely and a sudden onset of femur cortical fragility was detected on the 5th day following treatment.
Gastric Motor Activity during Feeding Induced by Stimulation of the Lateral Hypothalamus in the Rat
Authors: Glavcheva Luba , Manchanda S. K. , Box B. , Stevenson J. A. F.
Published: April 2011

Electrical stimulation of sites in the lateral hypothalamic feeding area of conscious rats elicited stimulus-bound feeding. Stimulation of the same sites when food was not available produced changes in gastric motility which depended on the initial state of gastric activity. If the stomach was active, gastric motility was inhibited; if it was quiescent, gastric motility was activated. In every case, however, a marked activation of gastric motility occurred after stimulation. Feeding behavior and concomitant changes in gastric motility were accompanied by a moderate increase in arterial blood pressure. Rats which did not exhibit feeding responses on lateral hypothalamic stimulation showed a stimulus-bound inhibition of gastric motility but no poststimulatory gastric activation.
Regulation of Intestinal Alkaline Phosphatase by Dietary Phosphate
Authors: McCuaig L. W. , Motzok I.
Published: April 2011

Day-old chicks were fed practical rations containing varying levels of inorganic phosphate (Pi) in an attempt to study the regulation of intestinal alkaline phosphatase by phosphate. Low dietary Pi (0.16%) increased the enzyme activity by 50% compared to adequate Pi (0.48%). The enzyme activities were significantly reversed 8 days after reversing the diets. In another experiment chicks were fed 0.16 or 0.80%) Pi for 4 weeks and killed when full-fed, or after 3 days' starvation. In the full-fed birds low dietary Pi reduced the intestinal nuclear Pi and doubled the intestinal enzyme activity. Nuclear Pi was found to be inversely correlated with alkaline phosphatase in the fed animals. No such effects were found in the starved birds.
The Membrane Binding of Morphine, Diphenylhydantoin, and Tetrahydrocannabinol
Authors: Seeman P. , Chau-Wong M. , Moyyen S.
Published: April 2011

The adsorption of morphine to guinea pig brain synaptosome membranes and to human erythrocyte membranes was found to be passive, and unaffected by time, temperature, ouabain, dinitrophenol, saponin, or ATP. The membrane/buffer partition coefficient for morphine was 35 (at low ionic strength) and 1.2 (at high ionic strength). The synaptosome membrane/buffer partition coefficient for diphenylhydantoin was around 60 (at pH 8), while that for Δ9-tetrahydrocannabinol (THC) was around 380 (in the concentration range of around 10−5 M). The partition coefficient for the latter drug dropped by a factor of two or three with increasing drug concentrations for both erythrocyte ghosts and synaptosomes; there may be two types of binding sites for THC. The minimum blocking concentrations (frog sciatic nerve) were 1.1 × 10−2 M for morphine, and 8.3 × 10−4 M for diphenylhydantoin. The anesthetizing membrane concentrations of these two drugs are close to the value predicted by the Meyer–Overton rule for local anesthesia (30 mmol/kg dry membrane).
The Effect of Glucagon on the Formation of Pancreatic Juice and Bile in the Rat
Authors: Shaw H. M. , Heath T. J.
Published: April 2011

The effect of porcine pancreatic glucagon on the formation of pancreatic juice and bile was studied in conscious rats. When the rats were fasting, intravenous infusions of glucagon were associated with depressions in the flow, and in the output of bicarbonate and protein in pancreatic juice (p < 0.001). By contrast, infusions of glucagon to rats during feeding were associated with increases in the formation of pancreatic juice, particularly the volume and bicarbonate fraction. The responses were greater than those recorded in rats that did not receive exogenous glucagon during feeding (p < 0.01). Glucagon did not appear to influence the formation of bile.
The Inhibition of Sympathetic Preganglionic Neurons by Somatic Afferents
Authors: Wyszogrodski Issie , Polosa Canio
Published: April 2011

The inhibitory effect of sciatic and ulnar nerve afferent stimulation on the firing frequency of sympathetic preganglionic neurons was studied in anesthetized or unanesthetized decerebrate cats, with intact spinal cords or with spinal cords sectioned at C2. The spontaneous firing and the firing evoked by antidromic stimulation, by iontophoretic glutamate, and by mechanical injury could be depressed, in the preparations both with intact and sectioned spinal cord. The depression was not preceded by excitation. The minimum stimulus strength required for the inhibition was, on average, 15 times the nerve threshold. The inhibition elicited by single shocks lasted several hundred milliseconds and was longer in the intact than in the spinal preparation. The results show that the neural pathway used by high threshold somatic afferents for inhibition of the sympathetic preganglionic neurons is complete within the spinal cord and suggest that the inhibition is probably acting on the preganglionic neuron membrane.
Measuring Rates of Appearance in Systems Which are not in Steady State
Authors: Norwich Kenneth H.
Published: April 2011

A general method is advanced for measuring the rate of appearance (production) of a chemical substance in an intact physiological system when this rate is changing with respect to time. The method involves infusing an isotope of this substance at such a rate that specific activity remains constant in space and in time. The means of achieving this constancy are discussed, and the mathematical basis of the method is developed for a fairly general system. An. experiment is described in some detail to show how the rate of endogenous production of glucose in a dog may be calculated when this rate is changing quite rapidly.
The Independent Effects of Changes in H+ and CO2 Concentrations on Pulmonary Hemodynamics of Intact Dogs
Authors: Malik A. B. , Kidd B. S. L.
Published: April 2011

The hydrogen ion concentration ([H+]) and the carbon dioxide tension [Formula: see text] of the arterial blood were varied independently of the other over a range of values while the respiration was controlled at resting levels. The independent effects of the two variables were examined in intact dogs anesthetized with 30 mg/kg sodium pentobarbital. Increases in [H+] and [Formula: see text] were significantly correlated (r = 0.859 and r = 0.646) with increases in the pulmonary vascular resistance (P.V.R.). The rise in P.V.R. in both cases was associated with rise in pulmonary perfusion pressure and no significant change in pulmonary blood flow. Decrease in [Formula: see text] had no effect on the measured parameters. We have demonstrated the independent pulmonary vasoconstrictor effects of increase in the [H+] and [Formula: see text]. The magnitude of the pulmonary vasoconstrictor response is dependent upon the degree of rise in [H+] and [Formula: see text]. [Formula: see text] does not play a role in maintaining resting pulmonary vasomotor tone.
Effect of Sodium Ethylmercurithiosalicylate (Thimerosal) on Serum Binding of Thyroid Hormones
Authors: Bellabarba Diego , Tremblay Raymonde
Published: April 2011

Sodium ethylmercurithiosalicylate (Thimerosal, Merthiolate) has been found to interfere with the binding of thyroid hormones to serum proteins. Dialysis studies showed that this compound, added to serum in concentrations varying from 90 to 360 mg/100 ml, caused an increase of the dialyzable or free fraction of thyroxine (T4) and triiodothyronine (T3). The increase was higher for the free T4 (3.8- to 18-fold) than for the free T3 fraction (2.3- to 5-fold). Electrophoretic studies on the distribution of tracer amounts of labeled T4 among the serum binding proteins revealed that the inhibitory effect of sodium ethylmercurithiosalicylate was exerted mainly on thyroxine binding globulin (TBG). In presence of this compound (180 mg/100 ml of serum) the percentage of tracer T4 bound to TBG was reduced from 53% to 9%. These findings were also confirmed by examining the binding of tracer amounts of labeled T4 and T3 in a serum diluted in barbital buffer, which inhibits the hormonal binding to thyroxine binding prealbumin and albumin. In presence of sodium ethylmercurithiosalicylate a significant displacement of both T4 and T3 from the serum binding protein (TBG) was observed.