bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Method for Continuous Measurement of the Carbon Dioxide Tension on the Cerebral Cortex
Authors: Siesjö Bo K. 
Published: December 2008

AbstractSiesjö B. K. A method for continuous measurement of the carbon dioxide tension on the cerebral cortex.A method has been developed for direct, continuous measurement of the pCO2 on the surface of the cerebral cortex, using a modification of the tissue pCO2 electrode earlier described (Hertz Siesjö 1959). The modification was made for the purpose of increasing the stability and accuracy of the measurements. The drift of the electrode was thereby reduced to less than 1 mV in five hours and the accuracy was increased to about ± 1.5 per cent. A reduction of the concavity of the pH glass membrane limited the response time of the pCO2 electrode to 25–30 sec following a twofold increase in pCO2. A description is given of the procedures for calibrating, suspending and thermostatting the electrode.The validity and reproducibility of the pCO2 values obtained when the electrode was applied to the cortical surface were investigated in cat experiments during respiratory and circulatory steady states. It was found that within a relatively wide range the pCO2 was independent of the pressure exerted by the electrode on the cortical surface. Provided that the tissue did not present any swelling and that the tissue surface was not damaged or allowed to dry, the pC2 varied very little (coefficient of variation 1.5 per cent) when the electrode was repeatedly applied to the same or to different cortical areas. The influence of superficial cortical vessels was confined to the larger veins (diameter 0.5–1 mm), across which slightly higher (1–5 mm Hg) values were recorded. The findings are discussed in relation to the applicability of the method in studies of the acid‐base metabolism of the tissue.
Oxygen Consumption and Sodium Reabsorption in the Kidney
Authors: Lassen Niels A. , Munck Ole , Thaysen Jørn Hess 
Published: December 2008

AbstractLassen N. A., O. Munck J. H. Thaysen. Oxygen consumption and sodium reabsorption in the kidney.Renal oxygen consumption can be divided into a small but constant basal oxygen uptake and a variable suprabasal or functional oxygen uptake. The basal oxygen consumption is defined as the oxygen uptake of the non‐filtering and hence non‐reabsorbing kidney. It was measured during marked hypotension and was found to amount to 1 μmole of O2 per gram kidney per minute. The suprabasal or functional oxygen consumption is defined as the total oxygen uptake minus the basal. It was measured on normally functioning kidneys and was found to correlate very closely with the quantity of sodium reabsorbed. For each mol of oxygen consumed in excess of basal requirements 28 sodium equivalents were reabsorbed. The hypothesis, that sodium reabsorption represents the main renal work is forwarded. It provides a simple explanation for the various classical observations on renal oxygen uptake and is in agreement with data on other electrolyte transporting tissues.
Histamine Release Elicited by Extracts from Ascaris Suis – Influence of Oxygen Lack and Glucose
Authors: Diamant Bertil 
Published: December 2008

AbstractIn guinea pigs intraperitoneal injection of Ascaris extract in doses effective in rats neither released histamine into the peritoneal fluid, nor“disrupted” mast cells in the mesentery. In vitro studies on Ascaris‐induced histamine release from rat lung tissue showed the release to be dependant on pH, incubation time and concentration of extract. Under oxygen lack, the histamine release by Ascaris extract diminished to about 9% of that in oxygen, but increased in the presence of glucose to about 80 % of the values found in the presence of both oxygen and glucose (5.6 mmole/1). With oxygen alone 60 % of this value was released. The enhancement of histamine release caused by glucose in nitrogen as well as oxygen suggests that it is dependant on enzymatic processes yielding high energy compounds.
Note on the Effect of Increased NaCl‐Concentration on the Neuromuscular Transmission Does Desensitization to Acetylcholine Take Place during Tetanus?
Authors: Lilleheil Gunnar , Naess Knut 
Published: December 2008

AbstractThe possibility of desensitization of the motor end‐plate to ACh during tetanus — as proposed by Thesleff — and the possible role of this desensitization for production of Wedensky inhibition of the neuromuscular transmission, have been tested and are discussed.As in Thesleff's experiments increased concentration of NaCl has been used to obtain block of contraction and pure end‐plate potentials. Mechanical registration of the contractions and extracellular recording of end‐plate potentials were employed.No signs of Wedensky‐inhibition could be obtained by increasing the NaCl‐concentration in the bath. Previous results indicate that the state of the motor end‐plate after long sustained strong increase in the NaCl‐concentrations must be rather unphysiological. The present results and also previous ones quoted in the discussion do not indicate any certain desensitization of the motor end‐plate to ACh under physiological conditions. A mechanism of this type can probably not be of particular significance for the production of the very rapidly occurring Wedensky inhibition seen, for example, during curarization.
The Functional State of Vasomotor Nerves to Skeletal Muscle Vessels in Reserpinized Cats
Authors: Rosell Sune , Rosén Anders 
Published: December 2008

AbstractThe functional state of vasomotor nerves to skeletal muscle vessels was studied in anesthetized cats treated with reserpine. The effects of the vasoconstrictor nerves could be completely blocked by reserpine while the responses of the vasodilator nerves seemed to be unaffected. The results are consonant with the view that there are two types of vasomotor nerves to the skeletal muscle vessels; namely, adrenergic vasoconstrictor nerves and cholinergic vasodilator nerves. The cardiovascular changes evoked by reserpine are discussed.
A Criticism of the Carcass Analysis Procedure for the Determination of Amino Acid Requirements
Authors: Ericson L.‐E. 
Published: December 2008

AbstractThe carcass analysis procedure is examined as a method for the determination of amino acid requirements. Using a simple reaction sequence to illustrate the fate of an amino acid in the body, enzyme kinetics are applied to demonstrate the impossibility of estimating the requirement of one compound in relation to another from knowledge of only the concentrations of the two compounds in the organism. The further complications arising from (a) the known individual variations in the concentrations of enzymes in the body, (b) the utilization by the organism of certain essential amino acids for purposes other than protein synthesis, (c) the partial ability of the organism to synthesize some essential amino acids, (d) the different rates of breakdown and excretion of the amino acids and (e) the fact that the body consists not of one but of a large number of different proteins with varying metabolic stability are briefly discussed. Some experimental data are cited which indicate that the carcass analysis procedure can give requirement values that are greatly erroneous. The criticism is presented with the hope that it will stimulate further theoretical and experimental studies in order to define the limitations and possibilities of the method.
The Persistence and Regularity of Electrical Activity in Whole Heart Explants
Authors: Cunningham A. W. B. , Lunell N. O. , Rylander B. J. 
Published: December 2008

AbstractThe electrical persistence and regularity of 143 chick embryo whole heart explants during nine days in culture is described. Details are given of culturing and surveillance of explants and handling of data. Over 90% of explants showed continuous electrical activity for nearly all of the first three days in culture. This percentage fell 6 % by the end of day three, 6 % during day four, 17 % on day five and more slowly thereafter. These changes possibly reflected inadequacies in the supernatant. The frequency and magnitude of change in the number of active cultures from one 15 second survey to the next slowly increased with a maximum of 1.2 cultures. It seemed that the failure of hearts to produce potentials was usually temporary and occurred in a rhythmic fashion. The difference between consecutive half‐hour averages of the number of cultures showing activity during 15 out of every 20 seconds was relatively high initially, dropped during the second day then rose again. It was always small compared to the total number of cultures involved. Comparisons between the persistence of electrical function in whole heart explants in various supernatants showed that the one used in this study was least inadequate.
The Effect of Choline 2,6‐Dichloro Phenyl Ether Bromide (TM‐25) on Organ Content and Urinary Excretion of Catecholamines
Authors: Schapiro S. 
Published: December 2008

AbstractDaily injections of choline 2,6‐dichloro phenyl ether bromide (TM‐25) in the rat greatly reduces the urinary output of noradrenaline and to a lesser extent that of adrenaline. After 5–6 days of treatment with TM‐25 the catecholamine content of adrenals, heart and spleen is considerably reduced. It is inferred from the results that TM‐25 interferes with the production, release or storage of catechol amines in the adrenergic nerves and possibly in the adrenals.
The Fate of Uniformly Labelled 14C Fructose in Different Parts of the Brain and the Pituitary in Goats
Authors: Larsson Stig 
Published: December 2008

AbstractThe fate of uniformly labelled 14C fructose has been studied in different parts of the brain and in the anterior and posterior pituitary. Generally, the metabolism of fructose was less than that of glucose. Particularly in the anterior part of the pituitary the fructose utilisation was small. As the oxygen consumption was little affected by the fructose, the utilisation of endogenous substances must be increased compared to experiments where glucose was used as substrate. The rate of conversion of fructose into various amino acids was considerably lower in the periventricular parts of the hypothalamus and in the anterior part of the pituitary as compared to the glucose experiments. The observed differences are discussed in relation to the importance of the pentose shunt.
The Influence of Rapid Injection of Concentrated Potassium Chloride Solution on the Cardiovascular Functions of the Cat in Respiratory Disorders
Authors: Antila L. , Hartiala K. 
Published: December 2008

AbstractThe effect of concentrated potassium chloride solution on the cardiovascular functions of the cat has been studied under severe asphyctic, hypoxic, and hypercapnic conditions. The potassium concentrations varied between 330–670 meq/1 and the total amount injected between 0.33‐0.67 meqK+ or 0.15‐0.35 meqK‐/kg b. w. The blood oxygen saturation and pH as well as serum potassium content were analysed before the injection. The effect of the injection was followed by continuous electrocardiogram and aortic pressure recordings. The 30 min period of respiratory disturbance did not cause any uniform changes in the serum potassium content. The cardiovascular changes prior to the injection were also unremarkable. The results indicate that the tolerance of the cat towards high potassium concentrations is mainly depressed by lack of oxygen whereas an excess in carbon dioxide does not appear to be so dangerous.
Gastro‐intestinal Excretion of Dextran‐C14
Authors: ÅBerg B. , Bloom W. L. , Hansson E. 
Published: December 2008

AbstractCats were given dextran‐C14 intravenously and the gastric juice as well as intestinal juices from intestinal segments and bile was collected during the first 6 hours after administration. The juices were investigated for radioactivity. It was found that there is a small excretion of radioactivity via the stomach and the liver. The intestinal juices however and chiefly those from the cranial parts of the intestine contained larger amounts of radioactivity which was precipitable with ethanol and represented dextran. The earlier literature on dextran metabolism is reviewed. The parallelism between the dextran and the albumin elimination via the gastrointestinal tract is pointed out.
Photometric Estimation of the Relative Amount of DNA in Early Chick Embryos
Authors: Emanuelsson Hadar 
Published: December 2008

AbstractUsing the two‐wavelength method the author has determined photometrically the amount of DNA in interphase nuclei of cells from chick blastoderms, 0—40 hours of incubation. The investigation was performed on sectioned material, stained according to the Feulgen method. Comparison of results for the different developmental stages shows that essentially only minor variations exist between the stages. Exceptions are the yolk endoderm cells at the 40‐hour stage which apparently are polyploid and cells from 5‐hour‐blastoderms which have an average of 40 per cent more DNA, than that found in other stages. In combination with a previous observation of a high level of DNA in early chick blastoderms the present result indicates a temporary occurrence of cytoplasmatic DNA in the chick embryo. The high DNA‐value at the 5‐hour‐stage is interpreted as indicating a partial synchronism in cell‐division during the early development of the embryo.
Mitotic Activity in Chick Embryos at the Primitive Streak Stage
Authors: Emanuelsson Hadar 
Published: December 2008

AbstractIn the present work it has been investigated whether previously recorded regional differences in the average RNA‐concentration of the primitive streak embryo are also connected with differences in mitotic activity. Mitotic indices calculated for the embryo area reveal no decided regional dissimilarities. However, owing to the uncertainty inherent in the interpretation of the index, it was decided to extend the mitotic counts to embryos in which a successive accumulation of mitoses had been produced by means of heat shock and the mitotic poisons, colchicine and oestradiol. From the obvious differences in mitotic activity which appear in such embryos it is clear that cell multiplication is greatest in a region of the embryo comprising the node and adjacent areas on both sides thereof. As differences in cell multiplication are moderate, however, it is presumed that the existing variation in RNA‐concentration must be partly ascribed to differences in protein synthesis within the embryo, associated with the beginning differentiation of the embryo cells. Cytologic and morphologic changes caused by the heat shocks and the mitotic poisons are described.
Effect of Intravenous Infusion of Glucose on Gastric Secretory Responses to Feeding in Pavlov‐ and Heidenhain‐pouch Dogs
Authors: Dotevall G. , Muren A. 
Published: December 2008

AbstractGlucose solution was infused intravenously (30%, 80–100 ml, 30 min) in conscious dogs with Pavlov‐ or Heidenhain‐pouches during secretion elicited by different procedures. In Pavlov‐pouch dogs a pronounced inhibition of the secretory response was observed during sham‐feeding or teasing with food; the response to feeding was also temporarily depressed, at least during the first two hours after feeding. In Heidenhain‐dogs the response to feeding compared with the Pavlov‐dogs was not significantly affected except during special conditions. It is suggested that the induced hyperglycemia mainly depresses the nervous phase of secretion, possibly both at the central and the peripheral level.
Effects of Ethanol on the Membrane Potential and Membrane Resistance of Frog Muscle Fibres
Authors: Knutsson Evert 
Published: December 2008

AbstractThe effects of ethanol on the membrane potential and membrane resistance of frog muscle fibres in vitro were studied by means of intracellular microelectrode technique. By continuous recording of the membrane potential level from one fibre, as well as by consecutive recordings from different fibres, the time course of the potential changes induced by different concentrations of ethanol was followed for periods of up to one hour. At the lowest concentrations used, 0.05 and 0.1 M, a depolarization, although slow and sometimes irregular, could usually be demonstrated. At a concentration equal to or higher than 0.2 M, a marked lowering of the membrane potential value was regularly observed. The depolarization rate increased with higher ethanol content, a typical result being a 15 per cent reduction of the initial membrane potential value after 15 min of exposure to 1.0 M ethanol. Reversal of the membrane potential changes after the ethanol had been washed out from the muscle bath was also demonstrated. Determinations of the voltage‐current relation of the muscle fibre, either by square pulse analysis or by direct recording of voltage‐current curves, revealed a gradual lowering of the membrane resistance, the effect increasing with the ethanol concentration from 0.2 to 1.0 M; at lower concentrations the changes in membrane resistance were within the normal variations found in untreated muscle.
Stratification of Absorbed Solutions in Mesenterial Veins1
Authors: ÖStling Gustaf 
Published: December 2008

AbstractStratification in the mesenterial venous blood of solutions which have been absorbed from the small intestine was demonstrated. Isotonic and hypotonic sodium phosphate solution and water were transported in the upper, and hypertonic glucose and saline solutions in the lower streamlines in the mesenterial veins. These observations show that the blood stream is laminar and that the streamline flow demonstrated previously in the portal vein after injection of dyes etc. also occurs in the mesenterial part of the venous portal circulation after intestinal absorption. No stratification could be demonstrated in the mesenterial veins after absorption of isotonic glucose and sodium chloride solution. The reasons for the presence and absence of stratification are discussed and different absorption mechanisms are considered. It is suggested that stratification depends on“intestinal short‐cut absorption”. According to this hypothesis, under certain conditions translocation from the intestinal lumen of intraintestinally instilled solutions to the capillaries takes place via gaps between the mucosal epithelial cells. These gaps are produced by expulsion of cells from the epithelial border during the absorption.
Human Serum Cholinesterase as a Sialo‐Protein
Authors: Svensmark Ole 
Published: December 2008

AbstractIncubation of human serum with sialidase (neuraminidase, receptor destroying enzyme) results in a marked decrease of the mobility of cholinesterase without affecting the enzymatic activity as indicated by the splitting of acetylcholine and butyrylcholine. The results suggest that human serum cholinesterase is an acid glycoprotein containing several sialic acid residues per molecule. In normal serum sialidase could not be detected whereas spinal fluid showed weak sialidase activity. In a single pool of serum from patients a marked sialidase activity was observed.
Augmented Cardiac Contraction, Heart Acceleration and Skeletal Muscle Vasodilatation Produced by Hypothalamic Stimulation in Cats
Authors: Rosén Anders 
Published: December 2008

AbstractHypothalamic stimulation in cats was found to produce an increase of the contractile force of the right ventricle as measured by a strain gauge arch. Concomitant tachycardia was generally observed. The responses were mediated both by cardiac sympathetic innervation and by catechols released from the adrenals. In some experiments the nervous mechanism dominated, in others the humoral factor. The hypothalamic area, the stimulation of which produced cardiac augmentation, appeared to correspond with“the sympathetic vasodilator area”. Muscle vasodilator as well as cardiac augmentative responses appeared concurrently.
Quantitative Differences Between Guinea‐Pig Ileum and Uterus in the Schultz‐Dale Reaction
Authors: Boréus Lars Olof 
Published: December 2008

AbstractAlthough the anaphylactic contraction of smooth muscle in vitro (the Schultz‐Dale reaction) is of the same type, intensity and duration in guinea‐pig ileum and uterus, some quantitative differences between these two organs are demonstrable. To produce equivalent contractions by addition of histamine to the bath, a ten times higher dose was required for uterus than for ileum. In the case of uterus, this amount was more than three times the total histamine content. Uterus released much greater amounts of smooth‐muscle stimulating substance during anaphylactic contraction than did ileum. In terms of histamine, 9 and less than 0.4 %, respectively, of the total content was released. Moreover, the mast‐cell disappearance, demonstrable only with the highest antigen doses used, was more pronounced in uterus.
Influence of Various Factors on Urine Oxygen Tension in the Dog
Authors: Aukland Knut , Krog John 
Published: December 2008

AbstractUrine pO2 (U‐pO2) was recorded polarographically for 2–4 hours in 17 experiments on anesthetized dogs. During air breathing values between 8 and 50 mm Hg were observed. Histamine, papaverine and Regitin invariably increased U‐pO2, with slight and inconsistant changes in total renal blood flow (RBF), renal venous pO.2 (V‐pO2) and urine flow. Single doses of adrenaline and nor‐adrenaline i. v. produced a rapid, transient reduction of RBF, V‐pO2, and urine flow, whilst U‐pO2, increased. Rapid i. v. infusion of hypertonic solutions of urea, mannitol or sodium chloride gave a rapid, transient increase of RBF, whilst U‐pO2, was lowered for several minutes. Oxygen breathing produced a marked rise in U‐pO2, whilst U‐pO2 increased slightly or remained unchanged. It is suggested that U‐pO2 is determined by pO2 in the renal papilla through equilibration across the walls of the collecting ducts. The main determinants are suggested to be 1. the rate of medullary blood flow, 2. medullary oxygen consumption, possibly dependent on the load of sodium to the medulla. Plasma skimming and counter current diffusion of O2 in the medulla is discussed. The findings are consistent with an independent regulation of cortical and medullary blood flow.
Cholinesterases in Human Spinal Fluid and Brain1
Authors: Svensmark Ole 
Published: December 2008

AbstractBy electrophoresis and chromatography on DEAE‐cellulose it was shown that human spinal fluid and brain tissue extracts contained three cholinesterases: Two butyrylcholinesterases and one acetylcholinesterase. One of the butyrylcholinesterases had the same electrophoretic mobility as serum cholinesterases. The other butyrylcholinesterase moved together with the γ‐globulin and the acetylcholinesterase together with the %‐globulin fraction of spinal fluid. These findings indicate that the acetylcholinesterase in spinal fluid derives from brain whereas it can not be decided whether the butyrylcholinesterases originate from plasma or from brain. The low mobility fraction of butyrylcholinesterase may arise from the action of sialidase.
The Loss of Added Lysine and Threonine During the Baking of Wheat Bread
Authors: Ericson L.‐E. , Larsson S. , Lid G. 
Published: December 2008

Rat growth experiments and microbiological assay methods were used to estimate the loss of added free L‐lysine·HCl and DL‐threonine during the baking of wheat bread. Introductory rat experiments showed that the optimum concentration for growth of L‐lysine. HCl added before baking was approximately 0.40‐0.45% of the fresh weight of the flour. The optimum concentrations of L‐lysine·HCl and DL‐threonine when added together were approximately 0.55% for the former amino acid and 0.30% for the latter. The loss of added L‐lysine·HCl during baking was found to be 10–15% as estimated by animal experiments and 5–10% as estimated by microbiological assays. The loss of L‐threonine (added as DL‐threonine) was significantly greater, amounting to approximately 40% as judged by the feeding trials and 20–25% according to the microbiological estimations.The amino acid compositions of the flour and the bread baked from the flour were also determined.