bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retention of Particles by the Reticulo‐Endothelial System
Authors: Juhlin Lennart 
Published: December 2008

AbstractJuhlin, L. Retention of particles by the reticulo‐endothelial system.Spherical particles of methyl methacrylate were injected intravenously in rabbits and mice. They are taken up by the R. E. S. primarily in the liver, spleen and bone marrow. The elimination from these organs was then studied, in some cases up to 18 months after injection. Three types of particles were used: Positively charged particles 0.05 μ in diameter and negatively charged particles 0.1 μ and 0.8 μ in diameter. These particles are all taken up by the R. E. S. and eliminated in a similar fashion. Approximately 50 per cent of the injected dose is eliminated from the body during the first month. In mice after 18 months about 10 per cent remained in the total body. Special polynuclear histiocytic cells were then found in the liver in which 0.8 μ particles could be seen with ordinary microscopy. The 0.8 μ particles increased in the spleen of rabbits and mice and in the bone marrow of rabbits during the first weeks. This seemed to be the result of a liberation of particles from the liver to the blood stream. The total amount of femur‐equivalent bone marrow in the rabbit skeleton was found to be 1.5 per cent of the body weight. The distribution of particles in different bones showed a bilateral symmetry, was not influenced by dose or particle size and was the same 3 hours and 20 days after injection.
Excitation, Inhibition and Rhythmical Activity in Hippocampal Pyramidal Cells in Rabbit
Authors: Euler Curt Von , Green J. D. 
Published: December 2008

AbstractEuler, C. V. and J. D. Green. Excitation, inhibition and rhythmical activity in hippocampal pyramidal cells in rabbit.The activity pattern of single hippocampal pyramidal cells has been studied in rabbit under light urethane anaesthesia and with encéphale isoléin response to various stimuli. Deep depolarization leading to initial excitation followed by in‐activation of spike generation has been found to be a commonly operating mechanism in the hippocampal pyramids. Such ‘inactivation processes’ have appeared spontaneously as well as in response to various stimuli. They may be driven with great precision as well as appearing rhythmically in after discharges. The ‘inactivation process’ was commonly followed by a hyper‐polarization. Thus two different mechanisms of inhibition followed each other. Prolonged septal stimulation provoked trains of rhythmically recurring inactivation processes with bursts of declining spikes at the rising phase of each depolarizing wave.Close similarities between the theta rhythm and rhythmically recurring inactivation processes are described and it is suggested that the former is built up by the latter synchronously occurring in several neurones. The inactivation process was also found to be a commonly occurring cellular event during seizure activity.
Interhippocampal Impulses
Authors: Andersen Per 
Published: December 2008

Andersen, P. Interhippocampal Impulses. III. Basal dendritic activation of CA3 neurorzs.The commissural afferents of the hippocampal field CA3 terminate in the layer of the basal dendrites only (Blackstad 1956), making selective basal dendritic activation possible. The response of CA3 in response to a symmetrical contralateral stimulation is a diphasic spike followed by a negative wave, sometimes with a superimposed spike. The diphasic spike represents interhippocampal fibre activity. The negative wave was recorded only from the CA3 basal dendritic layer. It is partly an excitatory postsynaptic potential produced in the basal dendrites by the commissural volley, partly a postsynaptic CA3 neuron discharge. The spike is a more synchronous discharge of the same neurons. The commissural volley elicits spikes more seldom in CA3 than in CA1, where apical dendritic activation is the most prominent, suggesting that a cell discharge is easier produced by apical than by basal dendritic activation. The susceptibility to anoxia is similar for the two fields. Strychnine normally produces great changes in CA1 potentials, but has only minor influence on the CA3 commissural response.
Thalamic Neurones Responding to Tactile Stimulation of the Cat's Tongue
Authors: Landgren Sven 
Published: December 2008

AbstractLandgren, S. Thalamic neurones responding to tactile stimulation of the cat's tongue.Encéphale isolé preparations were used. Extracellular spike potentials were recorded from single neurones in Nucleus ventralis posteromedialis of the thalamus. – The response of 40 thalamic neurones to tactile, thermal and gustatory stimulation of the tongue and to electrical stimulation of the tongue and the ipsilateral dorsal ascending trigeminal tract was investigated. Out of these neurones 32 responded only to touch, 4 only to pressure, and 4 to both touch and cooling of the tongue. One third of the neurones showed tactile receptive fields about 2 mm in diameter. Two thirds had larger ipsilateral or contralateral receptive fields. No large bilateral fields of the type shown by cortical “touch cells” were observed. – The typical response evoked in thalamic neurones by touch or electrical stimulation of the tongue was a short burst of spikes. Generally no after‐discharge was seen, but repetitive tactile stimulation sometimes caused an increase in the spontaneous discharge. The mean latency of the first propagated spike in the response of a “touch cell” to electrical stimulation of the tongue was generally 3–6 msec (shortest latency 2.5 msec). Most mean latencies of response to tract stimulation were 1–2 msec (shortest latency 0.9 msec).
Thalamic Neurones Responding to Cooling of the Cat's Tongue
Authors: Landgren Sven 
Published: December 2008

AbstractLandqren, S. Thalamic neurones responding to cooling of the cat's tongue.In encéphale isolé preparations extracellular spike potentials were recorded from single neurones in the thalamic nucleus ventralis posteromedialis (VPM). The effect on these neurones of thermal, mechanical, gustatory and electrical stimulation of the tongue and electrical stimulation of the ipsilateral dorsal ascending trigeminal tract was investigated.Out of 62 neurones fully investigated 20 responded only to cooling of the tongue, 4 to touch or pressure and to cooling and 1 to warming.The latency of the response of the “cold cells” was generally 6–14 msec to electrical stimulation of the tongue and 1.0–1.9 msec to stimulation of the tract.The response of “cold cells” to constant temperatures applied to the tongue and to rapid changes between constant temperature levels was investigated. A drop in temperature caused an increased frequency of discharge, which adapted to a new constant level. In the range 40–20° C the larger the drop in temperature the higher was the initial as well as the maintained frequency. Warming the tongue to 37° C reduced the discharge. Above 45° C an increase was again observed.The anatomical localization of the “cold cells” was laterally in. the medial parvocellular part of VPM.
Effects of RNA on Early Chick Embryos Cultivated in Vitro
Authors: Emanuelsson Hactar 
Published: December 2008

AbstractThe object of the present investigation has been to find out whether pure RNA can exert a stimulating action on the morphogenesis of early chick embryos. The experiments have been performed on 16 to 18‐hour‐old embryos cultivated in vitro. RNA from 1) area opaca of 2‐day‐old chick embryos 2) from heads of 6‐day‐old chick embryos and 3) from yolk‐sacs of 6‐day‐old chick embryos was tested. — After 24 hours' cultivation in vitro a marked growth and differentiation occurred in embryo‐regions homologous to those from which the RNA had been isolated. Other regions, however, were rather retarded in their development and displayed disturbed mitoses. Mitotic counts demonstrated an increased mitotic activity in the growth‐stimulated embryo‐regions. In the latter a slight increase in the percentage of anaphases + telophases also was noted. — Thus it appears that the pure RNA in itself has the capacity of stimulating growth and differentiation in chick embryos, the localization of the effect being dependent, however, on the origin of the RNA used.
Quantitative Studies on the Anaphylactic Mast‐Cell Reaction In Vivo in the Guinea Pig
Authors: Boréus Lars Olof 
Published: December 2008

AbstractThe anaphylactic reaction of tissue mast cells was studied quantitatively in vivo in the nasal mucosa of anaesthetized guinea pigs. Rising doses of antigen, given intraarterially or intravenously, caused proportional degrees of mast‐cell depletion in the tissue, as well as increasing intensity of the anaphylactic shock symptoms. Topical administration of different concentrations of antigen on the mucosa produced proportional degrees of mast‐cell disappearance, but gave no shock symptoms. A total mast‐cell loss in the mucosa was never seen, even following very high doses of antigen. The cell reaction was temporally closely connected to the onset of the anaphylactic shock symptoms. Maximum was found in 1 minute after intraarterial, and in 2 minutes after topical administration of antigen. The cell reaction and the corresponding anaphylactic shock could not be produced until the 9th day following the first sensitizing dose, but both could be provoked during more than 11 months after sensitization. The conclusion is drawn that the anaphylactic reaction in a guinea‐pig tissue is quantitatively reflected in the disappearance of the tissue mast cells.
Immuno‐electrophoretical Investigations of Mouse Serum Protein Fractions Obtained by Ammonium Sulphate Fractionation
Authors: Clausen J. , Heremans J. 
Published: December 2008

AbstractThis study contains data on 21 mouse serum proteins demonstrated by immuno‐electrophoretical analysis of normal F1 (CBA X DBA/2) mice. Supernatants and precipitates obtained with ammonium sulphate at concentrations ranging from 1.2 to 2.8 M were investigated immuno‐electrophoretically, and the precipitation range of most of the components was established. Data regarding the physicochemical properties of several mouse proteins are given as a basis for comparison with some of the better known serum proteins.
A Study of Pressure‐time Curves Obtained in the Occluded Renal Artery in Cats at Different Venous Pressures
Authors: Aarström Arne 
Published: December 2008

AbstractThe magnitude of the minimum arterial pressure for flow in the kidney at different venous pressures (VP) has been studied in anesthetized cats by observing the pressure drop in the renal artery after interruption of its flow for 2.0—2.5 min. At normal VP flow became “practically zero” (<0.0067 ml per min) when the renal arterial pressure (RAP) was 12.5 = 3.5 (S. D.) mm Hg and the mean arteriovenous (A‐V) pressure difference 7.6 ± 3.0 mm Hg. The cessation of flow under these conditions has been attributed to the collapsing effect upon the vessels of tissue pressure. At elevated VP the RAP usually falls to the level of VP. However, in four of twelve cases an A‐V pressure difference of 2–6 mm Hg was observed and has been attributed to a high vascular tone and/or high tissue pressure. This A‐V pressure difference at elevated VP is absent in the denervated preparation. Measures increasing vascular tone tend to augment the difference. Elevation of VP for some minutes causes an increase in resistance to flow which will influence the time course of the pressure drop and, in the case of constant volume perfusion, the value of the minimum arterial pressure for flow is elevated for 4–5 min after restoration of VP to the normal level. This effect of VP elevation is qualitatively similar to that produced at normal VP by perfusion of fluids with a lowered colloid osmotic pressure. The results seem fully explicable without invoking a hypothesis of a “venous arteriolar reflex”.
Resynthesis of Adrenaline in the Rabbit's Adrenal Medulla During Insulin‐Induced Hypoglycemia
Authors: Bygdeman S. , Euler U. S. v. , Hökfelt B. 
Published: December 2008

AbstractResynthesis of suprarenal adrenaline in rabbits during insulin hypoglycemia was calculated on the basis of the amount of adrenaline present in the gland and the amounts produced, estimated from the urinary excretion of adrenaline during a given period. It was found that depletion of adrenaline in the gland of the insulin treated animal was accompanied by a resynthesis, amounting to more than twice the average normal content in 24 hours.
Hämoglobinmenge und Blutvolumen der Ratte und ihre Beziehung zum Körpergewicht
Authors: Tribukait Bernhard 
Published: December 2008

AbstractThe total amount of haemoglobin and blood volume in the normal male rat has been estimated by a modified CO‐method and related to body‐weight. With increasing body‐weight the total amount of haemoglobin decreases from 0.8 g Hb/100 g body‐weight in the rat of 100–150 g to 0.68 g Hb/100 g body‐weight in the rat heavier than 450 g, and the blood volume decreases from 0.85 to 0.67 ml/100 g body‐weight. The results are compared with those of other workers and are discussed.ZusammenfassungHamoglobinmenge und Blutvolumen der normalen mannlichen Ratte wurden mit einer modifizierten CO‐Methode bestimmt und in Relation zum Korpergewicht gestellt. Mit steigendem Korpergewicht sinkt die Hamoglobin‐ menge von 0.8 g Hb/100 g Korpergewicht bei dem 100–150 g schweren Tier, das Blutvolumen von 0.85 auf 0.67 m1/100 g Korpergewicht. Die Resultate werden mit denen anderer Autoren verglichen und besprochen.
A Method for Recording General Activity of Mice
Authors: Arvola Alpo 
Published: December 2008

AbstractThe method is based on the movements of a mouse on the labile floor of the cage. The labile floor rests on a vertical metal axle in the center. Telephone exchange relays at the bottom in the center of each wall register the movements of the floor. The method is suitable for measuring activity during short periods, because the apparatus registers all movements of the mouse.
Studies of the Effect of X‐Rays on the β‐Glucuronidase Activity in the Gastric Mucous Membrane and in the Liver and of its Relation to the Glucuronide Conjugation
Authors: Hartiala K. , Näuntö V. , Rinne U. K. , Savola P. 
Published: December 2008

AbstractThe effect of local X‐irradiation of the liver and the stomach on the β‐glucuronidase activity was studied in rats. In the liver it was found that with the both radiation doses, 400 r and 1,200 r, there was an initial increase in the enzyme activity which was after the first day followed by a return slightly though insignificantly below the control level. After the 3rd day a new rise greatly above the control level was present. This persisted at least 2 weeks after the irradiation.In the gastric mucosa there was only a depression in the enzyme activity beginning already 3 hours after the irradiation. The depression continued over a period of at least 12 days. Comparison of the post‐radiation, β‐glucuronidase activity and the glucuronide conjugation capacity of the same tissues revealed a parallelism for the gastric mucosa. In the liver the same stimulation and depression phases were also present for the both activities. Still they were not parallel so that the time relationships showed a distinct dissociation. The possible meaning of these relations are discussed.
The Kinetics of Na24 Flux Across Amphibian Skin and Bladder1
Authors: Hoshiko T. , Ussing H. H. 
Published: December 2008

AbstractThe sudden addition of Na24 to the solution bathing one side of isolated frog skin or toad urinary bladder results in a steady increase in the labelled flux with time to a final steady state value. The build‐up of the labelled flux follows a single exponential course for both influx and outflux. This is consistent with a model involving a single sodium pool in the membrane. The build‐up half‐times for toad urinary bladder and for frog skin averages about 2–5 minutes and is not accountable as diffusion delay through the connective tissue. The steady state flux, divided by the time constant of flux build‐up, gives an estimate of the minimal amount of sodium in the pool, if only one pool is responsible for the delay. The calculated sodium pool size for urinary bladder and skin is in the same range, from 0.01 to 0.42 uMeq Na/cm2. This amount exceeds any amount imaginable as residing in the 250 Å thick basement membrane which has been proposed as the site of active transport. The pool is probably located in the epithelial cells, and the actively transported sodium passes through and not between the epithelial cells.
Inhibition of Cinchophen Ulcer in Chicks with Boiled Potassium Hydrogen Saccharate
Authors: Hartiala K. , Häkkinen I. 
Published: December 2008

AbstractSimultaneous feeding of saccharic acid lactone (1 1/2% of the diet) with cinchophen prevented completely the usual gastric ulcer formation up to the 10th day at which time the control group treated only with cinchophen had an ulcer in 60 per cent of the cases. At the 14th day the control group had ulcers in 85 per cent, whereas the saccharic acid treated group had ulcers and erosions in 55 per cent. Saccharic acid is known as a β‐glucuronidase enzyme inhibitor. The results are discussed in light of the possible relationship of the local glucuronide conjugation reactions and cinchophen ulcer mechanisms.
The Histamine Methylating Enzyme System in Liver
Authors: Lindahl Kerstin M. 
Published: December 2008

AbstractAn enzyme is described which catalyses the transfer of the methyl group of S‐adenosylmethionine to histamine at the imidazole nitrogen remote from the side chain. A method for the assay of the enzymic activity is described. The enzymic activity is enhanced with increasing pH. The influence of certain inhibitors examined suggests that the enzyme has essential sulfhydryl groups. Studies on the intracellular distribution indicate that the enzyme is localized to the soluble cytoplasm. The enzyme has been found in the liver of mouse, pig, hamster, rabbit, cat, and man.
Functional Organization of the Dorsal Spino‐Cerebellar Tract in the Cat
Authors: Lundberg A. , Winsbury G. 
Published: December 2008

AbstractRecording was made from fibres in the dorsal spino‐cerebellar tract activated by group I afferents from soleus. Adequate activation through brief stretches giving selective activation of I a or I b afferents was used to differentiate between units activated by I a and I b afferents. There was no evidence of convergence of excitatory action by I a and I b afferents to the same neurones. The receptive field is often larger for neurones activated by spindle than for neurones activated by tendon organ afferents.
Inhibitory Effects of Hydrochloric Acid in Antrum and Duodenum on Gastric Secretory Responses to Test Meal in Pavlov and Heidenhain Pouch Dogs
Authors: Andersson Sven 
Published: December 2008

AbstractInstillation of hydrochloric acid into the excluded duodenum inhibits the gastric secretion stimulated by test meal in both Pavlov and Heidenhain pouch dogs. This is in accordance with the assumption by several authors that a secretion‐inhibiting mechanism is activated by an acid milieu in the duodenum. The results also show that this mechanism operates independent of the vagal nerve supply to the gastric mucosa. Perfusion of an isolated antral pouch with hydrochloric acid had lesser and irregularly occurring inhibitory effects on the secretory responses in Pavlov pouch dogs.
Circulatory Studies on Substance P in Man
Authors: Dunér Hans , Pernow Bengt 
Published: December 2008

AbstractHighly purified substance P preparations were infused intravenously in doses of 0.2‐1.2 units per kg body weight per min in six healthy subjects. Red flushing, tachycardia and a rapid fall in arterial blood pressure were observed. Cardiac output was slightly increased. The effects were maximal after 1–2 min and gradually decreased during continued infusion.
On the Postnatal Development of Postural Mechanisms as Revealed by Electromyography and Myography in Decerebrate Kittens
Authors: Skoglund Sten 
Published: December 2008

AbstractThe present paper is one in a series of studies on the postnatal development of postural reflex activity in the kitten. Its aim is to investigate the reactions to decerebration and additional ablation of the anterior lobe of the cerebellum in these animals from birth until they are able to walk and stand. An attempt was made by electromyography and myography to trace the mechanisms behind the different reactions. It is shown that alpha rigidity is present in the newborn kitten while gamma rigidity develops later, appearing first in the forelimbs around a fortnight after birth and in the hindlimbs after three weeks. The missing gamma rigidity in the newborn animal is readily explained by the observation that no tonic stretch reflexes, as revealed by electromyography can be obtained from the muscles concerned with decerebrate rigidity. The tonic stretch reflex develops in a proximo‐distal direction in the limbs as revealed by electromyography and is earlier obtained in the alpha than the gamma animal and earlier in the forelimbs than the hindlimbs. This development thus precedes the gamma rigidity which in its development closely follows that of the animal's ability to use its limbs for walking and standing. It also runs in a cranio‐caudal direction.
The Spinal Transmission of Proprioceptive Reflexes and the Postnatal Development of Conduction Velocity in Different Hindlimb Nerves in the Kitten
Authors: Skoglund Sten 
Published: December 2008

AbstractThe postnatal development of the conduction velocity in different nerves of the hindlimb has been investigated in the kitten from birth to 4 months of age. It is found that the different fibre systems which have about the same conduction velocity at birth, with reference to conduction velocity, develop at different rates. Thus the large muscle afferents and efferents develop faster than the large fibres of the skin nerves and the latter faster than the gamma efferents. The conduction velocities reach adult values 3.5‐4 months after birth. It is also shown that proprioceptive reflexes can be mediated by arcs of two neurons in the newborn kitten. Furthermore the reflex time for the two‐neuron arc attains adult values when the conduction velocity of the fastest muscle afferents reaches 30 m/sec, which occurs around 20 days postnatally.
Zinc‐Induced Relaxation of Muscle Fibres
Authors: Edman K. A. Paul 
Published: December 2008

AbstractThe extractability of zinc from rabbit psoas muscle by glycerol‐extraction and by further treatment with EDTA and ATP has been determined as has the uptake of zinc by glycerol‐extracted fibres at bath concentrations of zinc corresponding to the free zinc ion concentration needed for induction of complete isometric relaxation of the fibres in the presence of ATP. The functionally relevant uptake of zinc needed for relaxation of extracted fibres could be covered by the total amount of zinc available in fresh muscle. Fully repeatable contraction‐relaxation cycles with glycerol‐extracted fibres in a highly plasticized state were produced with 0.6 mM total zinc simply by alternating the ATP concentration between 3 mM (relaxation) and 7 mM (contraction). The result was similar if, at constant total zinc (0.6 mM) and ATP (3 mM), 1.25 mM EDTA was alternately added (contraction) and removed (relaxation). Based upon these findings a possible mechanism for the action of zinc as a relaxing factor in vivo is presented: Relaxation is caused by inhibition of contractility by zinc; contraction is induced by release into the appropriate compartment of the fibre of a zinc‐complexing substance — ATP or a similar compound — which, after breakdown, again returns the complexed zinc with consequent re‐inhibition of contractility and, thus, relaxation.