bluuebunny/crossref_metadata_2025 huggingface dataset:
Muscle Training by Static, Concentric and Eccentric Contractions
Authors: Petersen Flemming Bonde
Published: December 2008

Isometric strength of the elbow flexors and the knee extensors was measured by a strain‐gauge dynamometer constructed according to Darcus (1953). The accuracy of this dynamometer was found to be ± 1–3 per cent. Seventeen young female and seventeen young male subjects underwent a training period of from 20 to 36 days. Their training constituted the performance of one of the following forms of exercise: 1 daily maximum isometric contraction, 10 daily maximum isometric contractions, 10 daily eccentric muscular contractions or 15 min of daily heavy dynamic work (riding a bicycle ergometer). The effect on the isometric strength and endurance of the trained muscle groups was measured and compared to a control group of 7 females and 6 males, who received no specific training, It was found that 1 daily maximum isometric contraction had no effect on the isometric strength of the muscles, 10 daily maximum isometric contractions had a tendency to increase the isometric strength of the muscles, while 10 daily maximum eccentric contractions had no measurable effect on isometric muscle strength. Heavy dynamic work increased the isometric strength of the muscles by 12 per cent in the females and 23 per cent in the males. There was no measurable effect on endurance to sustained isometric contractions consequent to any of the training programs. Training of muscles on one side did not modify the strength of the contralateral muscle groups.
Intermittent Muscular Work
Authors: ÅStrand Irma , ÅStrand Per‐Olof , Christensen Erik Hohwü , Hedman Rune
Published: December 2008

The physiological effect of rest pauses on a non‐steady state work (2,160 kpm/min) was studied. A physically well trained subject performed in one hour a total amount of 64,800 kpm on a bicycle ergometer by intermittent work with 0.5, 1, 2 or 3 min periods of work and rest. Total O2 intake, total pulmonary ventilation, total number of heart beats and blood lactic acid concentration during the work hour and during recovery were determined. It was found that the heavy work when split into short periods of work and rest (of 0.5 or 1 min duration) was transformed to a submaximal load on circulation and respiration and was well tolerated during one hour. With longer periods (of 2 or 3 min duration) the work output got close to the upper limit of performance and could be fulfilled only with the utmost strain. These findings are discussed from a physiological and practical point of view. In order to explain the low lactic acid values during the short periods of work and rest it was proposed that the myohemoglobin has an important function as an oxygen store during short spells of heavy muscular work.
Myohemoglobin as an Oxygen‐Store in Man
Authors: ÅStrand Irma , ÅStrand Per‐Olof , Christensen Erik Hohwü , Hedman Rune
Published: December 2008

The aim of the present research was to investigate further the possible r81e of myohemoglobin as an oxygen‐store during the initial stage of muscular work. One subject worked intermittently with a work load of 2,520 kpm/min with varied duration of work and rest pauses on a bicycle ergometer. A highly significant difference in the blood lactic acid concentration during the experimental time of 30 min was found, at work with short work periods (10 sec, lactic acid concentration about 10–20 mg per 100 ml) compared with relative long ones (60 sec, lactic acid concentration 110–140 mg per 100 ml). The conclusion was drawn that the first type of work is performed aerobically. The calculated oxygen demand, during the work period of 10 sec, however, does not correspond to the measured oxygen intake. A deficit of about 0.43 1 O2 for each period of work will occur. It was suggested that this amount of 0.43 1 O2 is supplied to the working muscle mainly from oxymyo‐hemoglobin. This store function of myohemoglobin is discussed in relation to the present findings and to the results mentioned in the literature.
On the Specificity of the RUM Like Joint Receptors
Authors: Eklund G. , Skoglund S.
Published: December 2008

The response pattern of Ruffini like receptors has been studied in some 60 knee joint capsule preparations, which in a Tyrode bath were exposed to a linear increase of tension. The response pattern was also studied while applying an additional tension increase at angles to the linear one. From the findings it was concluded that the sensitivity bands displayed by the sense organs in situ are only a reflection of tension alterations in the capsule and not of specific end organ properties.
Dynamic Elasticity in the Initial Phase of an Isotonic Twitch
Authors: Buchthal F. , Rosenfalck P.
Published: December 2008

A method is described which allows a continuous determination of the elastic and viscous component of the dynamic stiffness of isolated frog muscle fibres in vibration experiments. Elastic and viscous stiffness increased gradually in the initial phase of preloaded isotonic twitches. The increase started already within the mechanical latent period. Within 25 per cent of the time to maximum shortening elastic stiffness increased by 100 per cent and viscous stiffness by 50 per cent. In slightly stretched fibres, at the length in the body, the increase in dynamic stiffness during tetanic contraction was identical with that found in a twitch. In highly stretched fibres dynamic stiffness in a tetanus exceeded that of a twitch, presumably due to the redistribution of load between the contractile substance and the sarcolemma. The increase in dynamic stiffness during a twitch immediately after a prolonged tetanus was markedly lower than in a twitch performed before the tetanus. The contributions to the dynamic stiffness from the parallel elastic, the series elastic and the contractile component were evaluated. Although the periodical deformations were essentially confined to the series elastic component, the dynamic elastic properties give information about the contractile substance as the series elastic component mainly represents the elasticity of the contractile material.
Comparison of the Effect of Ethanol and Malonate on the Respiration of Rat Brain Cortex Slices
Authors: Wallgren Henrik
Published: December 2008

Ethanol and malonate both reduce the respiration of stimulated cerebral cortex tissue at concentrations which do not depress the oxygen uptake of unstimulated tissue. A study was made of the effects of these compounds added separately or simultaneously at low concentrations to a phosphate‐glucose saline. Within the concentration ranges employed (malonate 10‐4 ‐ 8 times 10‐4M, ethanol 8.7 times 10‐2 ‐ 1.96 times 10‐1M), the only effect on unstimulated tissue was a slight increase in respiration in presence of ethanol. In electrically stimulated tissue, malonate and ethanol both diminished the respiration. When the inhibitors were present simultaneously, the effect of one of them only was obtained, i. e. of that inhibitor having greater action at the particular concentration. This lack of synergism was taken as evidence for independent inhibitory action of ethanol and malonate.
The Effect of Body Position on the Circulation at Rest and During Exercise, with Special Reference to the Influence on the Stroke Volume
Authors: Bevegård S. , Holmgren A. , Jonsson B.
Published: December 2008

In 10 healthy, adult, male subjects the hemodynamics have been studied by the aid of heart catheterization at rest and during work both in supine and sitting positions. The cardiac output was on the average 2.2 1/min less in the sitting than in the supine position, both at rest and during exercise. In the supine position, the stroke volume was constant at rest and during exercise. In the sitting position, the stroke volume at rest was 40 per cent smaller than in the supine. It increased considerably with mild work, but not significantly with an even heavier work load. It never reached the values obtained in the supine position, even during heavy work. The arterio‐venous oxygen difference was larger in the sitting than in the supine position, both at rest and during work. During heavy work, the oxygen transport per heart beat was the same in the supine and the sitting positions, and the physical working capacity (work performed per heart beat) was also of the same order.
Circulatory Data in Normal Subjects at Rest and During Exercise in Recumbent Position, with Special Reference to the Stroke Volume at Different Work Intensities
Authors: Holmgren A. , Jonsson B. , Sjöstrand T.
Published: December 2008

Right heart catheterization has been performed in 18 healthy subjects, 14 males and 4 females, including estimation of cardio‐vascular pressures and cardiac output at rest and during different intensities of exercise in recumbent position. During exercise the cardiac output increased linearly with the oxygen uptake. The increase of the arterio‐venous oxygen difference in relation to the work load or the pulse rate was higher in the males than in the females. With change from rest to work the stroke volume increased slightly but significantly in the males. By increasing work load it successively decreased to the size at rest. There was a high correlation between the stroke volume on one hand and the work performed at pulse rate 170, the heart volume, and the blood volume on the other. The mean pressure in the pulmonary artery was 5 mm Hg higher during exercise than at rest but was constant at different work loads. The end‐diastolic pressure in the right ventricle and the mean pulmonary venous pressure (PC V‐pressure) did not change significantly with the increase in pulse rate.
On the Role of Monoamine Oxidase for the Inactivation of Dopamine in Brain
Authors: ROSENGREN EVALD
Published: December 2008

Evidence is presented that monoamine oxidase is involved in the metabolism of dopamine in brain. Thus 3,4‐dihydroxyphenylacetic acid has been demonstrated to occur in the brains of three species investigated, including man. That this acid was derived from dopamine after oxidative deamination seemed probable as it was found to be localized in the same areas of the brain as dopamine and it disappeared after inhibition of monoamine oxidase with iproniazid. The capacity of this enzyme in brain seemed to be sufficient for the plausible inactivation rate of dopamine in this tissue.
In Vitro Release of Histamine from Cat Skin by Compound 48/80
Authors: Westerholm Barbro
Published: December 2008

Westerholm, B. In vitro release of histamine from cat skin by compound 48/80.

A method for studying histamine releasing activity is described. Chopped cat skin was incubated with liberator and the histamine released was assayed on guinea‐pig ileum. The mechanism of action of compound 48/80 on this preparation was studied. It was shown that histamine release by 48/80 was dependent on time, concentration, temperature and pH. There were temperature and pH optima, though they were not well defined with the doses used. The release could be blocked by certain enzyme inhibitors as the amino group reagent, ninhydrin, and the sulfhydryl group blocking substance, allicin. The observations are considered to support the hypothesis that 48/80 acts by means of an enzyme mechanism.
The Biological Half‐Life of Bromide Ions in Human Blood
Authors: Söremark Rune
Published: December 2008

The biological half‐life of bromide ions in human blood was studied in 10 human subjects. The subjects were healthy students about 20 years old. The radioactive isotope, Br82, was given orally in form of NH4Br in water solution. Venous blood samples were drawn from the subjects twice a day. The biological half‐life of bromide ions in the blood was found to be about 12 days. The bromide ratio red blood cells/serum was found to be about 0.45. This was calculated by using the mean from ten hematocrit values obtained from every person. No bromide was found to be incorporated in fat, extracted from plasma and hemolysed blood cells by ether. Neither was there found any bromide incorporated in blood proteins. This was determined by precipitation with trichloroacetic acid, tannic acid, and phosphotungstic acid and anion exchanger, and paper electrophoresis.
Effect of Reserpine on the Storage of Catechol Amines in Brain and Other Tissues
Authors: Bertler ÅKe
Published: December 2008

Bertler Å. Effect of reserpine on the storage of catechol amines in brain and other tissues.

The effect of reserpine on the metabolism of dopamine and noradrenaline in tissues has been studied. Dopamine was found to be depleted from the brain at a higher rate than noradrenaline; dopamine decreased to 50 per cent of the normal level in 15 min while the corresponding time interval for noradrenaline was 45 min. The dopamine in the peripheral tissues of the sheep was found to be only slightly lowered within 13 hours, after administration of 2 and 4 mg reserpine per kg whereas the dopamine of the brains were reduced to insignificant amounts. In this respect it behaved in the same way as 5‐hydroxytryptamine (5‐HT). The rate of disappearance of catechol amines after reserpine is suggested to be dependent on the rate of turnover of the amines. The principal effect of reserpine on the tissue catechol amines and 5‐HT is supposed to be due to an interaction of the active transport of the amines into the storage sites. The results of the investigation indicate that the drug does not interfere with the decarboxylation of dihydroxyphenylalanine and 5‐hydroxytryptophan.
Occurrence and Localization of Catechol Amines in the Human Brain
Authors: Bertler ÅKe
Published: December 2008

BertlerÅ.,Occurrence and localization of catechol amines in the human brain.

The content of noradrenaline, dopamine and 5‐hydroxytryptamine (5‐HT) in various structures of the human brain has been investigated. Noradrenaline in rather high concentrations was found in the anterior and middle portion of the hypothalamus, and lower levels were recorded in structures of the mesencephalon and the floor of the 4th ventricle. Dopamine showed a very strict localization to structures which are involved in the extra‐pyramidal system, i. e. the basal ganglia and the substantia nigra suggesting that it may be involved in the function of this system. Relatively high concentrations of 5‐HT were found in the hypothalamus, the medulla oblongata, the corpus striatum and the thalamus.
Brief Cyclic Variations in Some Sexual Functions of the Male Rabbit
Authors: Degerman G. , Kihlström J. E.
Published: December 2008

G. Degerman J. E. Kihlström. Brief cyclic variations in some sexual functions of the male rabbit.

It has been demonstrated by means of two different statistical methods that at least two sexual functions of male rabbits, the volumes of daily ejaculates and the intensity of the sexual drive, are subjected to cyclic variations. The length of the cycle varies individually from 3 to 6 days, and is in some individuals superimposed by a longer period.
Influence of Noradrenaline on Spinal Interneuron Activity
Authors: Skoglund C. R.
Published: December 2008

SkoglundC. R.Influence of noradrenaline on spinal interneuron activity.

The effects of intra‐arterial and intravenous injections of noradrenaline on spinal interneurons have been studied on decapitate, curarized cats by means of intracellular technique. The most common effect, observed at a threshold dose of 1 μg per kg bodyweight, was an increase in excitability. Interneuron responses to single afferent volleys were facilitated, a typical effect being transformation of single spike responses into repetitive discharges. In the absence of any induced afferent stimulation noradrenaline injections were observed to set up discharges in initially silent cells and to cause an increase in frequency of prevailing activity, sometimes followed by a decrease. An initial decrease in excitability was only occasionally seen.
Effects of Intravenous Infusions of Adrenaline and Noradrenaline on Certain Psychological and Physiological Functions
Authors: Frankenhaeuser Marianne , Järpe Gundla , Matell G.
Published: December 2008

Frankenhaeuser M., G. Jarpe G. Matell. Effects of intravenous infusions of adrenaline and noradrenaline on certain psychological and physiological functions.

Effects of intravenously infused 1‐adrenaline (average dose 14.9 μg/min, average infusion time 34.7 min) and 1‐noradrenaline (average dose 16.2 μg/min, average infusion time 36.8 min) were examined by objective methods in six subjects. The psychological tasks were chosen so as to represent different functional areas. Heart rate and arterial blood pressure were continuously recorded, and excretion of urinary catechols before, during and after infusions was determined. Both drugs produced subjective symptoms (mental and physiological), and these were more pronounced and more frequent for adrenaline. Marked changes in heart rate and arterial pressure were recorded during the infusions. The stress involved in performing the psychological tasks also caused a pronounced increase in heart rate, arterial pressure and the urinary excretion of catechols. Performance did not differ significantly from that during the infusion of Ringer's solution. These results were tentatively interpreted to indicate that an increased alertness accompanying the emotional changes produced by the drugs may act to counterbalance other, unfavourable effects on performance.
Percutaneous Puncture of the Radial Artery with a Multi‐Purpose Teflon Catheter for Indwelling Use
Authors: Barr Per‐Olof
Published: December 2008

Barr P.‐O. Percutaneous puncture of the radial artery with a multipurpose Teflon catheter for indwelling use.

A Teflon catheter assembly is described, which was designed for percutaneous insertion and indwelling use in the radial artery, and in other superficial blood vessels with calibers of a similar order of magnitude. The advantages of the instrument, which may also be used for percutaneous puncture of other superficial tissues and organs, are reported and discussed, especially with regard to the preferential choice of the radial artery for arterial punctures.
Effect of Reserpine on the Storage of New‐formed Catecholamines in the Adrenal Medulla
Authors: Bertler ÅKe , Hillarp Nils‐Åke , Rosengren Evald
Published: December 2008

When L‐dopa (100 mg/kg body wt.) was given i.v. to reserpinized (5 mg/kg) rabbits, appreciable amounts of dopamine and noradrenaline rapidly formed in the adrenal medulla. The results support the view that reserpine does not — at least not to a great extent — interfere directly with the decarboxylating and β‐hydroxylating steps in the amine synthesis. To a great extent, however, the drug prevented the new‐formed amines from being incorporated in the storage granules, an incorporation which in normal animals is a very rapid and efficient process. It seems reasonable to assume that reserpine in some way blocks the process of monoamine storage. This may well be the main site of action of the drug.
The Role of the Adrenals on the Mucosal Mast Cells and Tissue Eosinophils in the Gastric Wall of Rat
Authors: Räsänen Toimi
Published: December 2008

The effect of ACTH on the mucosal mast cells and tissue eosinophils in the gastric wall of adrenalectomized and intact rats was studied. In intact rats, ACTH caused almost complete degranulation of the mucosal mast cells and a highly significant fall in tissue eosinophilia. Its degranulating effect on the mucosal mast cells and its tissue eosinopenic effect were inhibited after adrenalectomy. Adrenalectomy alone caused a slight increase in both these cell types in the gastric mucosa. The significance of mast cells as a mucosal histamine depot and its possible primary role as secretory stimulant of the parenchyma and secondary role in causing reduction of tissue eosinophilia is discussed.
The Effect of Deuterium Oxide on the Mechanical Properties of Muscle
Authors: Svensmark Ole
Published: December 2008

The effect of deuterium oxide on the isometric contraction of frog's muscle was investigated. In 99.8 per cent deuterium oxide the twitch force was reduced to 2–70 per cent of the force in aqueous Ringer, the rate of force development to 12–30 per cent, the tetanic force to 61–96 per cent while the latency of force development was approximately doubled. The total duration of the twitch was unchanged. The duration of the plateau of maximum intensity of active state remained unaltered by deuterium while its decline was enhanced. The conduction time of the action potential was not affected by deuterium but the reduction in frequency at which a complete tetanus could be maintained indicated an effect on the excitatory processes. It remained undecided whether the reduction in force is due to an effect of deuterium on the contractile elements or on the excitation‐contraction coupling.
The Comparative Effects of Angiotensin and Noradrenaline on Consecutive Vascular Sections
Authors: Folkow Björn , Johansson Börje , Mellander Stefan
Published: December 2008

The action of 1‐noradrenaline and angiotensin on the resistance and the capacitance vessels in a skin‐muscle region of the cat was studied by means of a technique recently described by Mellander (1960). Intravenous and close arterial infusions of the two substances showed that the constrictor effect of angiotensin on the resistance vessels is greater than that of corresponding amounts of noradrenaline. In the capacitance section, on the other hand, the constrictor responses to noradrenaline by far exceed those to angiotensin. On the basis of these results it is suggested that noradrenaline ‘receptors’ are to be found on the arterial as well as the venous side of the circulation, while angiotensin ‘receptors’ are essentially confined to the smooth muscles of the precapillary vascular region.
A Self‐Recording Electronic Osmometer for Quick, Direct Measurement of Colloid Osmotic Pressure in Small Samples1
Authors: Hansen A. Tybjaerg
Published: December 2008

A self‐recording electronic osmometer for clinico‐physiological use is described. It is a further development of an osmometer described earlier by the author. It is based on the passive counter‐pressure principle and as such representing a return to the principle that was first applied in osmotic pressure measurements. The general principles for the measuring of osmotic pressure and the special requirements to be fulfilled if quick performance is to be obtained are discussed. The importance of the diffusion phenomena in this context has been emphasized and experimentally elucidated. The sample of plasma or serum which is required, is from 0.02 to 0.1 ml. Ten to 15 measurements can be performed per hour. The confidence limits for one measurement are ± 0.5 mm Hg. at the 5% level. Commercially available cellulose membranes are used. No stopcocks are employed. Stainless steel is used for all parts in contact with membrane and sample. The possible usefulness of the osmometer for investigation of the reflection coefficient of permeating particles and for testing membranes is pointed out. Also the possible use in investigations of active trans port problems in connection with organic membranes is hinted at. Finally it is mentioned that the red blood cells under certain circumstances will influence the osmotic pressure.
A Comparison of the Distribution of Radioactive Fluorine and Calcium by Use of Double‐Isotope Autoradiography
Authors: Appelgren Lars‐Erik , Ericsson Yngve , Ullberg Sven
Published: December 2008

The autoradiographic distribution picture has been compared in whole pregnant mice and young rats at short intervals after the injection of fluorine (NaF18) and calcium (Ca45Cl2). The isotopes were injected intravenously on the same animal and selective registration of F18and Ca45was made utilizing the great difference in decay rates. Both isotopes, especially Ca45, were rapidly taken up from the blood. F18accumulated more rapidly and selectively in hard tissues while Ca45was taken up in appreciable amounts in some soft tissues. The distribution pattern in bone and in dentine was very similar for F18and Ca48. F18was taken up in proportionately low concentration in the calcifying molar enamel. Ca45but not F18was taken up in the cartilage of young animals.

A remarkably high accumulation of Ca45was seen in some groups of striated muscles. These muscle groups may be those which were contracted when the lightly anesthetized animal was sacrificed by immersion in the freezing mixture. The dominating excretory organ for F18was the kidney while high concentrations of Ca45appeared in the mucosa and contents of the small intestine.
Stimulation of Sweating by Exercise after Heat Induced“Fatigue” of the Sweating Mechanism
Authors: Ahlman K. , Karvonen M. J.
Published: December 2008

When wrestlers lose weight before a competition, they often induce sweating in a hot bath until the“fatigue” of the sweating mechanism. It is reported that at this stage exercise may still induce sweating. This claim was tested in experiments on five young males. After three or four exposures of 12 min each to ambient heat in a“sauna” bath which caused the rectal temperature to rise to values in a range from 38.4 to 39.4°C, substantial sweating could no more be elicited by repeating the thermal stimulus. However, treadmill running for 20 min caused a further weight loss of 0.1 to 0.9 kg, although the rectal temperature now remained on an average 0.7°C lower than during the preceding exposure to heat. The mean total loss of weight during the whole procedure was 3.6 per cent of the initial body weight.

The concentration of sodium, potassium and chloride varied individually at repeated exposures to heat. In most subjects, the range of the variation was small. During exercise the mean content of sodium was lower than in sweat collected during the first exposure to ambient heat.

The results are discussed.
The Effect of Small Doses of Alcohol on the “Optokinetic Fusion Limit”
Authors: Blomberg Lars‐H. , Wassen Anders
Published: December 2008

Optokinetic nystagmus was examined and registered electronystagmographically in the cases of 21 healthy subjects where the angular speed of optical stimulation was successively increased until the eyes could no longer follow the black and white bands on the optokinetic screen (the “optokinetic fusion limit”, OFL). This limit was also examined under the effect of a small dose of alcohol intravenously 0.8–1.6 g (concentration in serum of up to 5 mg/100 ml). The results showed a statistically significant decrease in OFL (P < 0.01). It is pointed out that the effect of small doses of alcohol on the eye movements is similar in certain respects to that of the barbiturates. No information concerning the exact site of action of alcohol on the central nervous system may be implied from those data.
Regional Blood Flow of the Cerebral Cortex Determined by Krypton85
Authors: INGVAR By DAVID H. , LASSEN NIELS A.
Published: December 2008

A new method for determining regional blood flow in tissue by means of the inert radioactive gas Krypton85is presented. The method has been applied on the exposed cerebral cortex of anesthetized rabbits, cats and dogs. The radioisotope Kr85, a weak beta emitter, was dissolved in saline which was then injected into the carotid artery of the hemisphere to be studied. The rapid uptake and slower clearance of the isotope was recorded from a small area of the exposed cortical surface, about 1 mm in depth. The theory of analyzing the clearance curves and of calculating the average regional cortical blood flow in ml per gram per minute is described. The method requires constant blood flow in the tissue during the measurement (about 5 min). It may, however, to some extent be used for studies of acute changes in perfusion. It is also possible to use it in a continuous fashion. It has been possible to confirm and to study in quantitative terms the correlation between arterial carbon dioxide tension or cortical functional activity, and the regional cortical blood flow. The method is simple to use and permits repeated measurements in the same experiment with minimal interference with the functional activity of the brain. The method may readily be adapted for studies in man
Regional Cerebral Cortical Metabolic Rate of Oxygen and Carbon Dioxide, Related to the EEG in the Anesthetized Dog
Authors: Gleichmann U. , Ingvar D. H. , Lassen N. A. , Lübbers D. W. , Siesjö B. K. , Thews G.
Published: December 2008

— The regional oxygen consumption and carbon dioxide production of a small area of the cerebral cortex (somato‐sensory cortex) in anesthetized dogs at steady state were determined quantitatively by means of a new method for measuring the regional cerebral blood flow (Lassen and Ingvar 1961, 1962) and by determination of the cortical arteriovenous difference of oxygen and carbon dioxide. Samples of cortical venous blood were obtained from the anterior part of the superior sagittal sinus after elimination of the diploic anastomoses. There were 26 complete sets of determinations. The a. v. differences (rAVDo1, and rAVDco2,) were found to be fairly stable (averages 11.3 and 11.7 vol. per cent). Large variations were found in the regional cortical blood flow (rCBF; 0.19 –1.06 ml per g per minute, average 0. 65 ± S.D. 0.23). The regional cortical oxygen consumption (rCMRo2 = rCBF × rAVDo2) hence varied between 2.3 and 13.4, average 7.0 (± S. D. 2.8), ml per 100 g tissue per minute. Studies of the EEG patterns prevailing at the time of the determinations showed that an EEG pattern dominated by faster frequencies (5–12 cycles per second) had an average rCMRo2, of 8.6 ml per 100 g per minute. A pattern dominated by high voltage slow waves (0.5 to 4 cycles per second) showed an average of 5.0, and a mixed EEG pattern of fast and slow waves an average rCMRo2 of 6.8 ml per 100 g per minute.
Formation of Phenolic Acids in Brain after Administration of 3,4‐Dihydroxyphenylalanine
Authors: Carlsson Arvid , Hillarp Nils‐Åke
Published: December 2008

— When L‐DOPA (100 mg/kg body wt.) was given i.v. to rabbits large amounts of first 3,4‐dihydroxyphenyl‐acetic acid (DOPAC) and then homovanillic acid rapidly accumulated in the brain stem. The data suggest that the dopamine formed in the brain from the administered DOPA first reaches sites of monoamine oxidase. The DOPAC thus formed then reaches sites of catechol‐O‐methyl transferase. The data also suggest that the accumulated phenolic acids do not easily escape from the brain to the blood.
Heat Exchange Through the Muskrat Tail. Evidence for Vasodilator Nerves to the Skin
Authors: Johansen Kjell
Published: December 2008

The importance of peripheral vascular adjustments in the regulation of thermal balance has been studied in 25 adult muskrats. This animal has a pelage of high insulative value while the tail is naked. The importance of the naked tail for maintenance of thermal balance was studied by plethysmographic techniques and measurements of tail and rectal temperatures. When subjecting the animal to a positive heat load by general body heating or following excercise, the tail skin temperatures rose to 35–37° C. Tail blood flow increased concomitantly by a factor of more than 400. The vasodilatation and subsequent increase in tail blood flow prevented heat accumulation and increase in rectal temperature during the positive heat load. Nerve block of the tail before heating or excercise precluded the described increase in tail blood flow and hyperthermia resulted. Nerve block at maximum blood flow led to a prompt decrease in tail temperature and a rapid increase in rectal temperature. It is concluded that the muskrat tail is an indispensible heat exchanger, reducing excess heat from increased metabolism or general body heating. The data indicate that the conspicious changes in tail blood flow are mediated through a sympathetic vasodilator mechanism.
Effect of Methanol, N‐Propanol and Acetaldehyde on Oxygen Uptake and on Blood Glucose Concentration in Anesthetized Rabbits
Authors: Perman E. S.
Published: December 2008

Increases in oxygen uptake and in blood glucose concentration after ethanol administration have recently been demonstrated in urethane‐anesthetized rabbits. The present experiments were performed to determine whether substances related to ethanol produce similar effects. The substances were infused intravenously. — Methanol and n‐propanol did not affect the oxygen uptake in doses comparable to the effective ethanol doses. This suggests that the effect of ethanol on oxygen uptake is not common to lower primary alcohols. Acetaldehyde, the chief primary ethanol metabolite, increased oxygen uptake in a smaller dose. It is tentatively suggested that acetaldehyde is involved in the production of increased oxygen uptake noted after ethanol. – Blood glucose increased only after methanol administration. The increase was not abolished by ganglionic blockade, suggesting that methanol and ethanol raise the blood glucose level via different mechanisms.
The Effect of Oxygen at High Pressure on the Histology of the Central Nervous System and Sympathetic and Endocrine Cells
Authors: Edström J.‐E. , Röckert H.
Published: December 2008

Rats were exposed to oxygen at 6 atm daily for about 8 weeks in one series and for 4 weeks in a second series. The exposure times were so adjusted as to give a low incidence of convulsions and lung symptoms. The treated animals did not show any evidence of lung damage at autopsy. Slight motor symptoms of a paralytic nature developed in some of the rats of the first series after about 2 weeks. The symptoms regressed during the continued treatment and had disappeared after further 5 weeks. Histological investigation of the nervous system after 7 to 9 weeks showed no degeneration. The rats of the second series exhibited no neurogenic symptoms. The exposures to high oxygen tension were found to have an action on the sympathetic nervous system resulting in an increased size of the nucleolus of neurons of the stellate ganglion and the adrenal medulla. In both series there was a decrease in the weight of the thymus, but the reduction was significant in the second series only. In agreement with earlier investigators a weight increase of the adrenals was found (P < 0.05 for the first series), and histologically, a thickening of the zonal fasciculata. A weight increase of the same statistical significance was obtained also for the thyroid. The histology of the pituitary was unchanged. Determinations of ribonucleic acid and size of nucleolus in the supraoptic nucleus did not reveal any changes. The investigation, consequently, could not provide any evidence for a direct degenerative action of OHP on the central nervous system. The observed changes are characteristic for a stress reaction. However, the weight increase of the thyroid is not typical for stress and may be an expression of a specific OHP effect.
Self‐Stimulation in the Goat
Authors: Persson Nils
Published: December 2008

A method is described to obtain intracerebral self‐stimulation in the goat. Permanent platinum iridium electrodes were implanted into the hypothalamus. The animal could elicit the electrical stimuli by pressing a switch connected to a stimulator that delivered trains of damped square pulses to the electrodes. High rates of self‐stimulation were obtained in the premamillary region of the hypothalamus between columna fornices descendens and tractus mamillothalamicus. The behaviour of the goats during self‐stimulation was observed, as well as the different rates and frequencies of self‐stimulation that they developed at various electrode sites. The influence of different strengths of current on the rate of self‐stimulation was also observed. In some parts where high rates of self‐stimulation were obtained, an increase in current strength up to 1.0 mA did not decrease the rate of self‐stimulation. A sudden change to stimuli in “rewarding areas” that never before had been tested with electric current immediately developed high rates of self‐stimulation. Amphetamine was tested on self‐stimulating animals. The drug increased the animals' urge for self‐stimulation.
The Solubility of Carbon Dioxide in Cerebral Cortical Tissue of Cats With a note on the solubility of carbon dioxide in water, 0.16 M NaCl and cerebrospinal fluid.
Authors: Siesjö Bo K.
Published: December 2008

The solubility of carbon dioxide in cerebral cortical tissue from cats was determined in homogenates, acidified to pH < 4 (cf. van Slyke, Sendroy, Hastings and Neill, 1928). The homogenates, which were prepared from brains frozen in situ with liquid nitrogen, were equilibrated with pure carbon dioxide at 37.5° C. The carbon dioxide content of the homogenates was determined by the microdiffusion method of Conway (1950) and the resulting Kuenen coefficients (ml CO2/g and ml CO2/g of H2O) calculated. A linear relationship was found between solubility coefficient and tissue concentration in the homogenates. Extrapolation to undiluted tissue gave the coefficients 0.49 (ml CO2/g tissue) and 0.61 (ml CO2/g of H2O in the tissue) respectively. The solubility of carbon dioxide in the tissue followed Henry's law, which should indicate that no appreciable amount of carbon dioxide is adsorbed onto tissue constituents. Measurement of the solubility coefficient for carbon dioxide in cerebrospinal fluid at 37.5° C revealed that this coefficient came very close to that obtained in a 0.16 M NaCl solution. The solubility coefficient in water, originally determined to test the methods used, was in good agreement with two, but in less good agreement with the majority of the coefficients reported in the literature. An examination of the literature indicated a source of error in the determination of the latter values.
The Reliability and Validity of a Physical Work Test
Authors: Borg Gunnar , Dahlström Hans
Published: December 2008

This investigation deals with the reliability and validity of different measurements of importance for the physical working capacity. Some physiological variables,e. g.pulse rate during a work test, have been correlated with each other, with some morphological variables and with an independent external criterion of the physical working capacity in the form of results from a skiing competition. The reliability of the work test on the bicycle ergometer was shown to be very high with intra‐test correlations as high as r = 0.97 and re‐test correlations (after about 8 months) r = 0.75. The highest validity correlation was 0.54 thus showing the usefulness of the work test on the bicycle ergometer.
Further Observations on the Effect of Anoxia on Histamine Release from Guinea‐Pig and Rat Lung Tissue in Vitro
Authors: Diamant Bertil
Published: December 2008

Histamine release was induced in vitro by antigen from sensitized guinea‐pig and rat lung tissue, and by compound 48/80 and Ascaris extract from non‐sensitized rat lung tissue. Preexposure of the lung tissue to nitrogen anoxia in the absence of glucose (“pre‐incubation”) markedly inhibited histamine release subsequently elicited under nitrogen in the presence of glucose, or under oxygen in its absence, whereas the same procedure had a comparatively smaller effect on histamine release induced under oxygen in the presence of glucose. Washing the lung tissue after“pre‐incubation” enhanced the histamine release subsequently induced under nitrogen with glucose, whereas histamine release under oxygen with or without glucose was less affected by the washing procedure. Rat and guinea‐pig lung tissue exposed to compound 48/80 and antigen, respectively, during“pre‐incubation” was found to be insensitive to a second exposure to the same histamine releaser. The results are explained on the assumption that high‐energy compounds available at the time of exposure of the lung tissue to the histamine‐releasing agents are of consequence for histamine release to proceed. They also suggest that the initial reaction (coupling of antigen to antibodies and of compound 48/80 to active sites) occurs without involvement of high‐energy compounds.
Competitive Effects of Sympathetic Control and Tissue Metabolites on Resistance and Capacitance Vessels and Capillary Filtration in Skeletal Muscle
Authors: Lewis David H. , Mellander Stefan
Published: December 2008

Reduction in regional blood flow to skeletal muscle impairs and eventually abolishes the responses of the resistance and capacitance vessels to both sympathetic vasoconstrictor nerve fibre activation and close intraarterial infusion of l‐noradrenaline. The resistance response declines more rapidly and is abolished earlier than the capacitance response. The more severe the degree of flow reduction the more rapid is the decline and the shorter is the time to abolition of both responses. Increased frequency of nerve stimulation and increased dosage of noradrenaline produce greater responses and can ‘protect’ reactivity, temporarily, against the effects of flow reduction. This protection is greater for the capacitance response than for the resistance response. Flow reduction also impairs precapillary resistance to a greater degree and more rapidly than postcapillary resistance. This interferes with and eventually abolishes the normal ability of the nerves to decrease mean capillary hydrostatic pressure and, thereby, to cause a net inward movement of extravascular fluid. Retention of postcapillary resistance response beyond that of precapillary results eventually in an outward movement of fluid on nerve stimulation. The data indicate that precapillary responses (precapillary resistance vessels, precapillary sphincters) are more under the influence of local dilating metabolic factors than are postcapillary responses (postcapillary resistance vessels, major capacitance vessels) which, in turn, are more dominated by extrinsic nervous factors. These observations provide a more precise understanding of the regulation of the local circulation and may aid in explaining the nature of the circulatory derangement in shock.
Distribution of Ingested Palmitic Acid‐1‐C14 between Rat Serum Lipoprotein Fractions
Authors: Karvinen Esko , Koskimies Olli , Miettinen Matti
Published: December 2008

Uptake of palmitic acid‐1‐C14 in albumin plus α1 lipoprotein fraction, in α2 lipoprotein, SbT lipoprotein and chylomicron fractions separated by paper electrophoresis was followed from 3 to 76 hours after oral administration of palmitic acid‐1‐C14. Except the initial high activity in the chylomicrons, the highest activity was found in the albumin plus α1 lipoprotein fraction. Apparent turnover time of this fraction between 3 and 18 hours after ingestion of the label was about 12 hours. Activity of the α2 lipoprotein fraction was not much altered up to 28 hours. Activity of the β lipoprotein fraction seemed to follow the activity of the chylomicron fraction to a greater extent.
Relative Adrenaline Content in Brain Tissue
Authors: Gunne Lars‐M.
Published: December 2008

Following chromatographic separation on a weak cation exchange resin (Amberlite IRC 50) adrenaline was identified in the brains of hens, pigs and rats by means of 1) the ethylene diamine condensation method, 2) the trihydroxyindole method and 3) bioassay on the hen's rectal caecum and cat's blood pressure. The percentage adrenaline in these species varied from 4,5 to 17. In brains of oxen and guinea pigs no adrenaline was detected, indicating less than 4 per cent adrenaline in these species.
The Relation Between Stimulus and Discharge in a Rapidly Adapting Touch Receptor
Authors: Lindblom U.
Published: December 2008

A quantitative experimental analysis was made in decerebrate toads of the relation between stimulus and discharge in touch receptors of the common rapidly adapting type. The stimuli consisted of mechanical pulses of variable slope, amplitude and duration. Recording was made from single afferent fibres in the dorsal root. The impulse frequency of the discharge from the very rapidly adapting receptors, and of the dynamic discharge from the less rapidly adapting receptors, varied with the gradient of the stimulus in a characteristic way. When the rate of the displacement was successively increased from the minimum effective value (critical slope), the impulse frequency was low at first, and then rose as a logarithmic function of the displacement rate (Fig. 2, 3, 5 and 6). The range of rates in which the change in frequency occurred was called the optimal slope range of the receptor. The impulse frequency was independent of the amplitude of the displacement in the very rapidly adapting receptors (Fig. 1 and 3 B), and only partially related to it in the less rapidly adapting ones. The demonstrated relation between displacement rate and discharge frequency constitutes a basis for an exact reproduction of the temporal characteristics of the stimuli and may be of primary importance for tactile discrimination.
Der Einfluss chronischer Hypoxie entsprechend 1,000 — 8,000 m Höhe auf die Erythropoiese der Ratte
Authors: Tribukait Bernhard
Published: December 2008

A device is described for the maintenance of a constant low air pressure. Rats were held under hypoxia equivalent to 1,000—8,000 m altitude for several months. Total hemoglobin was determined according to a modified alveolar CO‐method. Total hemoglobin at sea level was about 0.75 g/100 g body weight, increased significantly at 1,000 m and to 1.1 g at 4,000 m. A maximum of 2.2 g was at 6,000 m. The limit of survival was reached at 8,000 m. New levels of total hemoglobin was reached after 20 and 40 days at 5,000 respectively 6,000 m. An additional supply of iron had no effect. Hemoglobin per 100 ml. blood was 14, 19 and 26 g at sea level, 4,000 respectively 6,000 m. Hematocrite was 45 % at sea level, 60 % and 85 % at 4,000 m and 6,000 m respectively. Hemoglobin concentration parallels hematocrite values during hypoxia. Blood volume increased by 20—50 % at 6,000 m but plasma volume decreased by 10—20 %. Hemoglobin per unit body weight decreased with increasing body weight in animals adapted to 5,000 and 6,000 m, also the blood volume at 6,000 m. The daily production of hemoglobin was calculated from the total hemoglobin and the assumed life span of 60 days for erythrocytes. It increased to 4—5 times the normal during the first two days regardless of degree of hypoxia, but was thereafter a function of the degree of hypoxia.
Reflex Responses and Recurrent Discharges Evoked by Stimulation of Laryngeal Nerves
Authors: Maåtensson A.
Published: December 2008

Reflex responses in intrinsic laryngeal muscles to stimulation of the internal laryngeal nerve were studied with a view to elucidating the mechanism of the protective reflex closure of the glottislpsilateral stimulation evoked reflex discharges of multisynaptic character in all four vocal cord adductors studied but never in the abductor in which only inhibition of pre‐existent activity was observed. Contralateral stimulation evoked similar reciprocal effects but the discharges in the adductors were smaller and of longer latencies and did not appear in all muscles; latent contralateral reflex connections could, however, be demonstrated in all muscles. The reciprocal innervation pattern and the difference in transmitter potentiality of different reflex connections are discussed. 2/ Proprioceptive mechanisms in the laryngeal musculature were investigated. Stimulation of individual muscle nerves evoked, in nerve and muscle, in addition to the direct response, a secondary response amounting to a few per cent of the primary response. By performing an analysis in analogy with previous work on the spinal cord it was concluded that the secondary response represented a recurrent discharge from the motoneurons, whereas no response exhibiting the properties of a monosynaptic reflex was observed. Attempts to record afferent impulses from muscle spindles gave negative results. The findings are discussed in relation to earlier results from morphological and physiological studies of proprioceptive systems in the larynx.