bluuebunny/crossref_metadata_2025 huggingface dataset:
ENDOTHELIAL CELL MITOSIS AND PERMEABILITY
Authors: Stehbens W. E.
Published: December 2014

Endothelial cell regeneration following mechanical trauma to veins has been studied in the rabbit. Mitoses were observed most frequently on the 3rd day and stigmata and stomata probably representing intercellular gaps were observed at the equator of dividing endothelial cells during and after telophase. This could account for the increased permeability of growing capillaries.
THE HEMOGLOBIN, OXYGEN, CARBON DIOXIDE AND HYDROGEN ION CONCENTRATIONS IN THE UMBILICAL BLOODS OF SHEEP AND GOATS AS SAMPLED VIA INDWELLING PLASTIC CATHETERS
Authors: Meschia Giacomo , Barron Donald H. , Cotter Julian R. , Breathnach Caoimhghin S.
Published: December 2014

A method is described for the introduction of plastic catheters into the umbilical vessels of fetal goats and lambs whereby samples of blood may be obtained over a period of days and weeks in conditions in which the mother is free from obvious stress. The results of the analyses of samples so obtained, indicate that (1) the oxygen capacity of the fetal blood does not increase after 100 days and (2) that the oxygen saturation does not fall systematically in the last month of gestation. Data on the day to day variations in the blood levels of oxygen, carbon dioxide and pH are reported.
ULTRASTRUCTURE OF VASCULAR ENDOTHELIUM IN THE FROG
Authors: Stehbens W. E.
Published: December 2014

An electron microscopic investigation of the endothelium of capillaries and venules of the frog (Hyla cœrulea) revealed, as well as the usual cytoplasmic constituents, several new features.

In the endothelial cells three types of vesicle were encountered, each of which could be highly selective in the transport of materials across the vessel wall. The well‐recognized micropinocytotic vesicles of light density were most numerous. Less frequently seen, and hitherto unobserved in endothelium, were the dense‐walled micropinocytotic vesicles which at other sites are associated with protein uptake. Large vesicular spaces similar to the macropinocytotic vesicles described by Fawcett [1963] were readily observed.

Fenestrated endothelium occurred in attenuated segments of endothelial cells in the tongue as well as in the gut. Fenestrae were seen in the walls of macropinocytotic vesicles and along the cytoplasmic processes projecting into the lumen or along those which overlapped adjacent cells.

At intercellular clefts, tight junctions predominated. Occasional intermediate junctions were found but no desmosomes.

Thick basement membranes, the result of the coalescence of a thin endothelial basement membrane and thick convoluted laminae related to pericytes and adventitial cells, were found about vessels particularly in the tongue.

Microtubules and microtubular bodies of unknown significance were observed.
THE DIFFUSIBILITY OF OXYGEN ACROSS THE SHEEP PLACENTA
Authors: Meschia Giacomo , Cotter Julian R. , Breathnach Caoimhghin S. , Barron Donald H.
Published: December 2014

Estimates have been made of: (1) the oxygen tension in blood samples drawn from unanesthetized ewes and their fetuses via chronic catheters in the uterine vein, umbilical artery and umbilical vein between 90 days and full term; (2) the rate of oxygen uptake by the umbilical circulation between 80 and 134 days in a series of anesthetized ewes, and (3) the ‘diffusing capacity’ of the placenta for oxygen in eleven anesthetized ewes in stages of gestation from 81 to 134 days. The results demonstrate: (1) there is no regular change with advancing gestation in the oxygen tension of the blood in the vessels sampled, and (2) the quantity of oxygen taken up by the umbilical blood and the ‘diffusing eapacity’ of the placenta for oxygen both increase as the fetal weight.
JUNCTIONAL COMPLEXES OF THE HAMSTER VAGINA, UNDER NORMAL AND EXPERIMENTAL CONDITIONS
Authors: Vargas‐Linares Clara E. Roigde , Burgos Mario H.
Published: December 2014

The ultrastructure of the different junctional complexes of the stratified epithelium of the hamster vagina at late metestrus has been studied both under normal conditions and after perfusion with EDTA. Four types of junctions are described through which the vaginal cells adhere both to each other and to the basement membrane. These junctions are: the typical desmosome; the tight junction; the adhering band, and the basal junction.

After the calcium depletion due to EDTA, the desmosomes open up and there is a disappearance of the central laminar density. This causes the extension of the intercellular spaces. The other junctions, with the exception of the adhering bands in the vicinity of the desmosomes, appear to be resistent to EDTA.

These EDTA‐induced changes are similar to those produced by leucocyte invasion of the vaginal epithelium in metestrus.
THE EFFECT OF WIND‐SPEED ON HEAT PRODUCTION IN THE NEW‐BORN PIG
Authors: Mount L. E.
Published: December 2014

New‐born pigs were exposed singly in a closed respiratory metabolism chamber to wind‐speeds of 5, 34, 82 and 158 cm./sec. at ambient temperatures of 20 and 30° C. A rise in wind‐speed increased the metabolic rate, but not as much as expected from a heated cylindrical model, probably due to reductions in mean skin temperature, and in effective surface area possibly due to postural change.
THE EFFECTS OF SODIUM DEPLETION AND POTASSIUM SUPPLEMENTS UPON ELECTRICAL POTENTIALS IN THE RUMEN OF THE SHEEP
Authors: Scott D.
Published: December 2014

Measurements were made of the electrical potential gradient between the blood and the rumen contents of sheep made sodium deficient by the withdrawal of parotid saliva.

Loss of saliva resulted in an increase in the concentration of potassium and a fall in the concentration of sodium in the rumen fluid, and these changes were associated with an increase in the rumen potential. The results suggest that a potential arising from the passive diffusion of potassium into the blood may contribute significantly to the total potential which is generated across the rumen wall. The change in rumen composition appears to be due to a change in the relative amounts of sodium and potassium entering the rumen. This results from both the loss of saliva and a change in the composition of saliva entering the rumen, since the ratio of Na: K in the parotid saliva falls in response to sodium deficit through the secretion of adrenal hormones.

There is, so far, no indication that adrenal hormones exert any independent influence on the rumen potential other than through a change in the composition of the saliva and rumen fluid.
BONE STRENGTH AND CALCIUM RETENTION OF RATS IN HYPERVITAMINOSIS‐A
Authors: Khogali A.
Published: December 2014

Newly‐weaned male albino rats were fed by gavage excessive doses of vitamin A for 4 weeks either alone or with one of the thyroid hormones: L‐triiodothyronine and D‐triiodothyronine. Some rats were given the thyroid hormones alone. It was found that:

1. The rats fed 6000 i.u. and 12,000 i.u. vitamin A per day gained weight normally and did not sustain spontaneous fractures.

2. A dose of 24,000 i.u. vitamin A per day retarded the growth of the rats and spontaneous fractures of the long bones (mainly tibiæ) occurred.

3. The bones of the animals suffering from hypervitaminosis‐A were abnormally thin and their bending moment at breaking was significantly reduced. The breaking stress (quality) of the bones was also reduced but this can be explained by a change in texture of the bones and is not due to altered quality of the bony material. The stiffness (E) of the bones was not affected.

4. The percentage mineral content of the bones from hypervitaminotic rats was normal, but the total calcium retention of the animals was reduced.

5. L‐triiodothyronine and D‐triiodothyronine in doses of 5 µg. per day aggravated the skeletal changes in hypervitaminosis‐A.

6. The thyroid hormones alone did not produce any significant changes in the physical properties of the femora of rats.

It is suggested that, in hypervitaminosis‐A, the quantity and distribution of the bony material is disturbed but its quality is probably unaltered.
SIMULTANEOUS MEASUREMENT OF UTERINE AND UMBILICAL BLOOD FLOWS AND OXYGEN UPTAKES
Authors: Meschia Giacomo , Cotter Julian R. , Makowski Edgar L. , Barron Donald H.
Published: December 2014

A method is described for the simultaneous estimation of uterine and umbilical blood flows and oxygen uptakes. A test stubstance, antipyrine, was infused at constant rate in the fetal circutlation. About 50 min. after starting the infusion a steady state was attained in which the rate of transplacental diffusion of the test substance was equal, blut for small corrections, to the rate of infusion. During the steady state, blood samples were collected from uterine and umbilical arteries and veins and analyzed for antipyrine and oxygen. Flows and oxygen uptakes were calculated according to Fick's principle. Thie results of sixteen experiments on sheep and goats sh1ow that: (1) transplacental diffusion of antipyrine is mainly flow‐limited, (2) the placenta simulates a concturrent system of exchange, and (3) the oxygen uptakes of the fetus and the utero‐placental mass were, in many cases, of similar magnitude.
RÔLE OF ADRENERGIC FACTORS IN THE PRODUCTION AND PERPETUATION OF ATRIAL FLUTTER IN THE DOG
Authors: Sharma P. L.
Published: December 2014

The rôle of adrenergic factors in the production and perpetuation of atrial flutter has been studied in dogs under pentobarbitone sodium anaesthesia. The adrenergic influence was (a) increased by sympathetic stimulation or by intravenous injection of adrenaline and noradrenaline and (b) decreased by depletion of cardiac stores of catecholamines by previous treatment of the animals with reserpine.

Sympathetic stimulation, as well as adrenaline and noradrenaline increased the atrial rate in aconitine‐induced and post‐stimulatory atrial flutter, and in some cases the flutter was converted into fibrillation. Atropine sulphate only partially blocked the increase in flutter rate, but atrial fibrillation never occurred after atropine administration.

In some cases of aconitine‐induced atrial flutter, as the peak effect of adrenaline was passing off the atrial rate fell below that of sinus rhythm for a few seconds, and then gradually increased to the control level. No such response was seen after noradrenaline administration.

When cardiac stores of catecholamines were depleted by previous treatment of the animals with reserpine, aconitine produced long‐lasting atrial fibrillation in all the experiments. Atropine injection converted atrial fibrillation into slow rate atrial flutter. In such animals, electrical stimulation produced transient atrial fibrillation, the rhythm returning to normal sinus rhythm, a few seconds to a few minutes after the stimulation ceased. It was not possible to induce stable atrial flutter despite repeated attempts, and even after the administration of atropine.

The mechanism of these findings is discussed.
BRAIN AND CONSCIOUS EXPERIENCE. Study Week September 28 to October 4, 1964 of the Pontificia Academia Scientiarum. Edited by Sir John C. Eccles. Berlin, Heidelberg, New York: Springer‐Verleg. Pp. xxi + 591. DM. 67,20
Authors: Walsh E. G.
Published: December 2014

In the Review of Brain and Conscious Experience edited by Sir John Eccles, on p. 223, line 19 of text, ‘Adrain's’ should read ‘Adrian's’.
THE EFFECT OF INTRAVENOUSLY INFUSED SALINE ON THE RENAL CLEARANCES OF INULIN AND PARA‐AMINOHIPPURATE IN DOGS
Authors: Ramsay D. J. , Coxon R. V.
Published: December 2014

In the paper by D. J. Ramsay and R. V. Coxon in the Quarterly Journal of Experimental Physiology (1967) 52, 145–149 in Table II on p. 148, the second column should be headed Injection Method, and the third column should be headed Injection Method plus Infusion.
THE EFFECTS OF VASOPRESSIN, THEOPHYLLINE AND CYCLIC 3'‐5'‐ADENOSINE MONOPHOSPHATE (CYCLIC AMP) ON SODIUM TRANSPORT ACROSS THE FROG SKIN
Authors: Baba W. I. , Smith A. J. , Townshend Mary M.
Published: December 2014

The effects of vasopressin, theophylline and cyclic AMP on sodium transport across isolated frog skin have been studied using 24Na for the measurement of sodium fluxes. Both vasopressin and theophylline produced consistent increases in short‐circuit current, sodium influx and efflux, with a reduction in partial resistance of the skin. The same results were obtained with cyclic AMP only when it was combined with small (loses of theophylline which were by themselves ineffective. The similarity of effect of these three compounds on sodium transport mechanisms strengthens the hypothesis that the physiological activity of vasopressin may be mediated by cyclic AMP.
THE EFFECTS OF BOTULINUM TOXIN ON THE PATTERN OF INNERVATION OF SKELETAL MUSCLE IN THE MOUSE
Authors: Duchen L. W. , Strich Sabina J.
Published: December 2014

Sublethal quantities of botulinum toxin were injected into the gastrocnemius and hamstring muscles of one leg in mice. Local paralysis and atrophy occurred and persisted for a few weeks. Histological examination showed no degeneration of nerve fibres or of motor nerve endings. Silver impregnations showed that during the period of muscle paralysis there was growth of motor nerve fibres from the terminal arborizations. Nerve fibre overgrowth was accompanied by elongation and abnormal configuration of sites of cholinesterase activity. As muscle function recovered the nerve fibre overgrowth receded and well‐formed though still abnormally shaped subneural apparatuses were seen. Nine months after the injection of the toxin, the pattern of innervation of the muscle was still abnormal.

The growth of motor nerve fibres after the injection of botulinum toxin appears to be a response to the failure of neuromuscular transmission and is not analogous to regeneration of nerve fibres after trauma.
THE EFFECT OF VAGAL STIMULATION AND ESERINE ON ISOLATED GUINEA‐PIG ŒSOPHAGUS
Authors: Bartlet A. L.
Published: December 2014

The response of the isolated œsophagus to vagal stimulation was blocked by tubocurarine, decamethonium or nicotine, and was partially antagonized by hyoscine or hexamethonium. The response of the separated external muscle to vagal stimulation was antagonized by tubocurarine or decamethonium, but not by hyoscine or hexamethonium. The muscularis mucosæ and the œsophagus contracted to eserine, 5 µg./ml., after a delay of 2–3 min., but the external muscle did not. Hyoscine antagonized eserine acting on the œsophagus or muscularis mucosæ.
RESPIRATORY AND CARDIOVASCULAR CHANGES DURING ASPHYXIA AND RESUSCITATION OF FŒTAL AND NEWBORN RABBITS
Authors: Godfrey S.
Published: December 2014

A study has been made of the respiratory and circulatory responses to asphyxia and resuscitation of fœtal and newborn rabbits. Fœtuses were both delivered and maintained under isotonic saline, while newborn animals were asphyxiated in an atmosphere of N2 after light ether anæsthesia. Both groups were resuscitated by intermittent positive pressure ventilation with 02, begun after the last spontaneous gasp of asphyxia.

The response to asphyxia was very similar in the two groups. There was a short initial period of (primary) apnœa, accompanied by a sudden fall in heart rate and blood pressure. This hypotension and bradycardia during the early part of asphyxia was reduced by vagotomy. Following primary apnœa, the animals gasped for some 15–20 min. and then again became apnœic (secondary apnœa). The heart rate and blood pressure fell further and, in the absence of external interference, the animals died. Resuscitation was successful, provided the blood pressure was above 5 mm. Hg at the start of I.P.P. ventilation. The heart rate and blood pressure invariably rose before the return of respiration in the successful cases. The Hering‐Breuer and paradoxical reflexes were fully active in the newborn rabbit, but were abolished by asphyxia due to a central nervous block. They did not return for several minutes after resuscitation.
MECHANICAL AND CHEMICAL CONTROL OF BREATH HOLDING
Authors: Godfrey S. , Campbell E. J. M.
Published: December 2014

A method is described for the study of breath holding in which the breath holds are separated by rebreathing to enable accurate control of pCO2; its theoretical basis is discussed.

At the end of a breath hold, rebreathing a mixture such that the pCO2 continues to rise, nevertheless permits the breath hold to be resumed. The number of breaths during the rebreathing is unimportant and a single breath permits as long a resumed breath hold as five breaths.

Healthy adult males held their breath at residual volume. The relationship between breath holding time and pCO2 at the start or end of a breath hold was found to be linear; the higher the pCO2 the shorter the breath holding time. The relationship was unaffected by ten minutes of isocapnic hyperventilation.

These findings imply that the duration of breath holding is directly related to pCO2 but is unaffected by the previous mechanical pattern of breathing.
HUMAN CARDIOPULMONARY RESPONSES TO EXERCISE: COMPARISONS BETWEEN PROGRESSIVE AND STEADY STATE EXERCISE, BETWEEN ARM AND LEG EXERCISE, AND BETWEEN SUBJECTS DIFFERING IN BODY WEIGHT
Authors: Cotes J. E. , Allsopp D. , Sardi F.
Published: December 2014

The regressions of the oxygen uptake on rate of work, of the ventilation and cardiac frequency on oxygen uptake, and of the ventilation on tidal volume have been obtained over the ranges where they were linear during pedalling and during cranking a cycle ergometer. The regression coefficients for ventilation and cardiac frequency on oxygen uptake are higher for light than for heavy subjects, and for work which is performed with the arms instead of the legs; possible reasons are discussed. The respiratory frequency in relation to tidal volume is also higher for arm than for leg work. In the comparison of progressive and steady state exercise no systematic differences were observed, except for the relationship of the consumption of oxygen to the rate of work; this finding is relevant to the planning of exercise studies on normal subjects.
FUNCTION OF LIVER AND OTHER ORGANS DURING LYMPHATIC OBSTRUCTION IN SHEEP
Authors: Heath Trevor
Published: December 2014

Sheep remained clinically normal and showed no signs of oedema after the thoracic duct was ligated; normal secretion of bile salts and fatty acids into the bile was demonstrated, and serum sorbitol dehydrogenase concentration did not increase. However the clearance of sulphobromophthalein from the plasma was impaired, and this may have been due to a decreased rate of transfer between the lumen of the sinusoids and the vicinity of the hepatic cells. The ability of the intestine to absorb fat was slightly impaired after lymphatic obstruction but it was still capable of absorbing a mean of 88·3 per cent of a dose of 14C‐tripalmitin. The volume of plasma and the total amount of circulating plasma protein increased, and the concentration of lymphocytes in the blood decreased after the thoracic duct was ligated, but the operation without duct ligation did cause pronounced alterations in these parameters. Many direct connections between lymphatics and veins had developed by five to eight weeks after the operations, and all but one of these connections entered the hemiazygos vein or its intercostal tributaries.
INHIBITION BY THE SYMPATHETIC OF ADRENALINE'S ACTION ON DOG'S HINDLIMB VASCULAR RESISTANCE
Authors: Hadjiminas John , Maltesos Christos
Published: December 2014

The action of intravenous adrenaline on the vascular resistance of the dog's hindlimb is altered when sympathetic stimulation is given either before or after the adrenaline. The increase in vascular resistance produced by adrenaline is greatly reduced immediately after the recovery of the blood flow from a reduction due to a brief sympathetic stimulation. This partial inhibition of adrenaline's action wears off in 6–12 min. Further, the effect of intravenous adrenaline follows a much shorter time course if during it the sympathetic is stimulated for a period of 2‐4 sec. The mechanism of this phenomenon is discussed.
INNERVATION OF THE OVARY OF THE DOMESTIC HEN
Authors: Gilbert A. B.
Published: December 2014

The intrinsic innervation of the domestic hen's ovary consists of nerves running to the follicles and blood vessels. Both adrenergic and cholinergic components were identified.

The extrinsic supply was a complex network of ganglia and nerves; the ovarian and adrenal plexuses were particularly extensive. Nerves were traced from both left and right sympathetic chains. No positive identification of a parasympathetic supply was made but, in view of the cholinergic fibres that were found within the ovary, it is probable that such a supply was present.

The possible role of the innervation is discussed in relation to reproductive activity.
ULTRASTRUCTURE OF THE PULMONARY MICROCIRCULATION IN EXPERIMENTAL STREPTOCOCCAL BACTERÆMIA
Authors: Stehbens W. E. , Kostianovsky M. , Sonnenwirth A. C.
Published: December 2014

An electron microscopic investigation was made of the changes in the small blood vessels of the alveolar walls of rabbits' lungs five minutes to five hours after intravenous infusion of 20 ml. of a pure suspension of Streptococcus sanguis in sterile saline. The most prominent feature was the presence of numerous leucocytes (neutrophils, macrophages and eosinophils) containing in phagocytic vacuoles bacteria which displayed progressive degenerative changes. Phagocytosis by leucocytes was well established by five minutes. Platelets became aggregated about bacteria and leucocytes forming sizeable thrombi. Many platelets underwent lysis and not uncommonly bacteria were aggregated in masses of cellular debris. Incontrovertible proof of extracellular digestion of bacteria by platelets was not obtained. Osmiophilic material was observed both intracellularly and extracellularly but no definite fibrin deposition was observed in these experiments. Evidence of phagocytosis by endothelium and platelets was found, but the principal phagocyte in the pulmonary microcirculation was the leucocyte. The ultrastructure of Streptococcus sanguis is described.
THE FINE STRUCTURE OF THE INFUNDIBULUM AND MAGNUM OF THE OVIDUCT OF GALLUS DOMESTICUS
Authors: Wyburn G. M. , Johnston H. S. , Draper M. H. , Davidson Maida F.
Published: December 2014

The mucous membrane of the infundibulum and magnum of the hen's oviduct is modified for the receipt and fertilization of the yolk and the elaboration of the bulk of the solid material making up the white of the egg. The secreting surface is arranged in a series of ridges which are particularly elaborate in the neck region of the infundibulum. The surface is lined with columnar epithelial cells and there is a sub‐epithelial layer of tubular glands. There are two types of epithelial cell; ciliated, with little evidence of secretory activity; and granular, with the intracellular structure of a glycoprotein secreting cell. In the infundibulum the granular cells have electron dense granules and the tubular glands arise as invaginations from the epithelium of the deep crypts between the mucosal folds. The gland cells are structurally similar to the epithelial granular cells and have a characteristically large infranuclear granular endoplasmic reticular (GER) space filled with homogeneous material of low electron density, probably representing storage of synthesized protein. In the magnum the granules of the epithelial cells are of low electron density and fill the whole of the distended granular cell in the lower magnum, compressing the neighbouring ciliated cells.

Three types of tubular gland cell are described in the magnum: Type A, filled with electron dense granules; Type B, filled with large masses of homogeneous material of low electron density; and Type C, occupied by GER cisternae together with a large and prominent Golgi area. The C cells, which are found in the magnum immediately after the passage of the egg, are regarded as the recovery phase of A cells which have discharged their granules on the passage of the egg. There is evidence that the dense granules of the A cells represent ovalbumin, the commonest protein of the egg white. The fibrous glycoprotein, ovomucin, with its large carbohydrate component, is probably produced by the granular cells of the magnum epithelium. There is a partial discharge of the secretion of the cells of the mucous membrane in response to the presence of the yolk. The nature of the secretion and the origin of some other components are discussed.
EFFECTS OF HISTAMINE AND ACETYLCHOLINE ON THE ISOLATED PERFUSED LUNG LOBE
Authors: Kira Shiro , Rodbard Simon
Published: December 2014

Osmotic, surfactive, and hydrostatic forces were controlled in the Ringer‐Locke perfused, isolated lung lobe of the dog. Changes in the volumes of the airway space and of the total lobe, and in the rate of flow through the vascular bed were recorded. Each injection of acetylcholine (5·6 to 176 ng per gram of lung lobe) or histamine (42 to 139 ng per gram of lung lobe) was followed by an immediate shrinkage of the lobe and by a slightly delayed extrusion of fluid from the airway. The fall in pulmonary vascular conductance (flow rate/arteriovenous perfusion pressure) varied with the instantaneous difference in the changes of the total lung volume and of the airway volume. It appears that as acetylcholine or histamine causes contraction of the smooth muscle of the airways, the lung shrinks and the airway pressure rises. The lowered alveolar capillary transmural (vascular minus airway) pressure collapses the capillaries and reduces pulmonary vascular conductance. The effects on vascular conductance are due to the altered airway resistance rather than to direct effects on the blood vessels.
EFFECT OF CS AEROSOL UPON LUNG GAS TRANSFER AND ALVEOLAR VOLUME IN HEALTHY MEN
Authors: Cotes J. E. , Dabbs J. M. , Evans M. R. , Holland P.
Published: December 2014

Measurements of transfer factor (Tl'), alveolar volume (VA') and KCO (transfer co‐efficient for carbon monoxide; Tl' ÷ VA') have been made by the single breath carbon monoxide method with a single breath determination of alveolar volume before and after exposure to CS aerosol on 11 volunteer servicemen. For each subject the study occupied 3 days of which the first and third were control and post exposure days respectively. The exposure to CS was on the morning of the second day for approximately 1 hr to a concentration which was increased progressively from about 0·6 to 2·0 mg m−3. During the study no changes were observed in the alveolar volume or its subdivisions, vital capacity and residual volume. The transfer factor and KCO were rather higher on the first control day before exposure than on the post exposure day, with the day of exposure intermnediate. Exposure to CS aerosol was followed immediately by an increase in transfer factor and subsequently by a transient decrease to below the initial value. The changes were of small magnitude and quite insufficient to exert any material effect upon gas exchange; they were probably due to variations in vasomotor tone asociated with the procedure affecting the distribution of body blood volume, including the volume of blood in the lung capillaries.
RESPONSE OF SINGLE VAGAL AFFERENT FIBRES TO MECHANICAL AND CHEMICAL STIMULATION OF THE GASTRIC AND DUODENAL MUCOSA IN CATS
Authors: Davison J. S.
Published: December 2014

Single afferent fibres were dissected from the cervical vagus of adult cats and their response to mechanical and chemical stimulation of the gastroduodenal mucosa studied. All the units responded to light phasic mechanical stimulation of the mucosa but two different types of unit could be distinguished on the basis of their response to chemical stimulation. One type of unit responded to acidification of the mucosa while the other responded to application of high pH solutions to the mucosa. Each unit responded to one or other of these two forms of stimulation but not to both. Nor did any unit respond to any other form of chemical stimulation.

Other functional characteristics, the location of the mucosal endings and the pathways of the units between the abdomen and neck are described. The possible role of these afferent units is discussed.
THE STRUCTURE AND FUNCTION OF THE SLOWLY ADAPTING TYPE II MECHANORECEPTOR IN HAIRY SKIN
Authors: Chambers Margaret R. , Andres K. H. , Duering Monika v. , Iggo A.
Published: December 2014

The slowly adapting type II mechanoreceptor in hairy skin of the cat was studied in detail using histological and neurophysiological methods. The end organ (Ruffini ending) was lightly encapsulated, situated in the dermis and supplied by one axon which bifurcated within the capsule to form a terminal arborisation. A serial diagrammatic reconstruction was made of one ending. The afferent units almost invariably carried a resting discharge and responded to vertical displacement of the skin over an area of 2·5 sq. cm and to directional stretching of the skin over an area up to 25 sq. cm. For each unit there was a single small region of maximum sensitivity (less than 2 sq. mm). The response to vertical displacement consisted of a dynamic and static phase, linked by a period of adaptation. These three phases were subjected to quantitative tests, using displacements of different amplitude, velocity and duration. The units were directionally sensitive to skin stretch and this response was of a similar pattern to that caused by vertical displacement. The units were temperature sensitive over a range from 14°–42°C and the resting discharge was increased by a fall in skin temperature and temporarily silenced by an increase.
DISTRIBUTION AND PROPERTIES OF MUSCLE SPINDLES IN THE CAUDAL SEGMENTAL MUSCLES OF THE RAT TOGETHER WITH SOME COMPARISONS WITH HIND LIMB MUSCLE SPINDLES
Authors: Andrew B. L. , Leslie G. C. , Thompson J.
Published: December 2014

The afferent activity in sensory nerve fibres was recorded when lateral segmental muscles of the rat tail were stimulated mechanically. The muscles were then examined histologically and the muscle spindle content established. The distribution of spindles along the tail length and their innervation pattern was obtained. The overall ratio of primary to secondary endings was approximately two to one. Most single spindles (67% of sample) were intermediate; parallel (dual) spindles (29% of sample) usually combined a simple with an intermediate spindle; complex spindles were rare.

The maximum muscle extension during tail‐bending movements was a submaximal stimulus to tail spindles; there was no resting discharge in the straight tail position in the absence of fusimotor stimulation.

The spindle endings were compared with those in rat hind limb muscles in terms of dynamic index, vibration sensitivity, spindle complexity and conduction velocity of afferent fibres. In all four aspects the tail values were more restricted in range; all caudal spindle endings had lower dynamic indices, lower vibration sensitivity and lower afferent conduction velocities than those found in primary endings in the three hind limb muscles examined (peroneus longus, peroneus brevis and gastrocnemius lateralis). A positive correlation between spindle afferent conduction velocity and vibration sensitivity of caudal spindle endings was recognized, and the possible role of afferent fibre size in determining spindle properties discussed.
RELEASE OF GLUCAGON, INDUCED BY STRESS
Authors: Bloom S. R. , Daniel P. M. , Johnston D. I. , Ogawa Olivia , Pratt O. E.
Published: December 2014

When conscious, lightly restrained primates were startled by noise, the level of glucagon in the plasma rose rapidly and this rise was followed by an elevation of blood glucose but not of plasma insulin. In anaesthetized animals similar effects were produced by unpleasant stimuli (rectal distension, drilling a burr hole in the skull or the passage of an electric current through the head). These experiments show that glucagon is rapidly released in response to various types of stress.
EFFECT OF ADDED DEAD‐SPACE ON PULMONARY VENTILATION DURING SUB‐MAXIMAL, STEADY‐STATE EXERCISE
Authors: Kelman G. R. , Watson A. W. S.
Published: December 2014

Six normal subjects exercised for 6 min at 30%, 50%, and 70% of their predicted Vo2max, with and without an added respiratory dead‐space of 1,200 ml. The added dead‐space caused a marked increase of V2/MVV15%, the values at the three work loads being, respectively: without dead‐space, 20·4%, 30·1%, and 44·2%; and, with dead‐space, 41·1%, 48·6%, and 68·7%. These increases of V2 were due mainly to increases of tidal volume, but ventilatory frequency increased also, the values being: without dead‐space, 21·0, 25·5, and 30·4 breaths/min; and with dead‐space 25·4, 28·4, and 33·9 breaths/min. At the highest work load the V2/VC ratio without dead‐space was 44·0%, and with the dead‐space 62·6%. Possible reasons for the breathing pattern adopted by the subjects are discussed.
THE MITOSIS OF SHEEP BLOOD MONOCYTES IN TISSUE CULTURE
Authors: Greenwood B.
Published: December 2014

A technique is described by which sheep blood monocytes have been collected in tissue culture chambers and maintained in frequent changes of 100% autologous blood plasma. Such cells grow in size, and, having assumed a large macrophage form, they divide by mitosis. The cultures have been observed daily and their mitotic indices determined by counting 2,000 cells. These indices peak about the eighth day in culture. Mitotic activity then diminishes and usually dies out. The products of mitosis are two daughter cells which have macrophage size and morphology, and never at any time resemble fresh blood monocytes. These events have been confirmed by continuous recording with time‐lapse cine‐photomicrography.

The work demonstrates the proliferative capacity of the mammalian blood monocyte. The cell collection technique and the observation and continuous recording of living cultures have been directed at refuting any possible criticism that mitoses were occurring in contaminating fibroblasts.
THE EVALUATION OF A MACHINE FOR INTRODUCING TOBACCO SMOKE INTO THE LUNGS OF ANAESTHETIZED ANIMALS DURING SPONTANEOUS RESPIRATION
Authors: Armitage A. K. , Houseman T. H. , Turner D. M. , Wilson D. A.
Published: December 2014

1. A new smoking machine is described for introducing a measured sample of a 25 ml. puff of tobacco smoke into the lungs of anaesthetized cats, or other experimental animals with similar respiratory characteristics.

2. Important features of the machine are that undiluted smoke is taken directly into the lungs during essentially normal respiration and that the dose administered can be monitored.

3. The efficiency of the machine in administering nicotine and carbon monoxide has been measured. The presentation of smoke to the animals' lungs is considered to resemble the way in which the human cigarette smoker ‘inhales’ smoke into his lungs.
CALCIUM TRANSPORT BY THE CHICK CHORIOALLANTOIS IN VIVO
Authors: Crooks R. Jane , Simkiss K.
Published: December 2014

A technique is described for attaching a perspex annulus to the chorioallantoic membrane of the chick embryo. Radioactive saline is placed on this membrane and the uptake measured in vivo. The method gives calcium influx values of 85·4 n mole/cm2/hr for 12‐day and 115·9 n mole/cm2/hr for 15‐day embryos. Efflux measurements obtained by analyzing accumulated radioactivity in the 15‐day embryo give a value of 113·2 n mole/cm2/hr. The values obtained with these techniques are similar to the rates of calcium absorption from the eggshell during normal development.
THE INFLUENCE OF PHENTOLAMINE ON THE HYPERGLYCAEMIC AND LIPOLYTIC EFFECTS OF AMMONIA IN SHEEP
Authors: Wiechetek Maria , Garwacki S. , Barej W.
Published: December 2014

Intravenous infusion over 30 min of ammonium chloride [0·1 g/kg b.w.] caused a significant increase of blood glucose and free fatty acids levels, and a similar effect was observed with adrenaline. Phentolamine [1 mg/kg b.w.] abolished the hyperglycaemic action of ammonium chloride but only slightly diminished the lipolytic effect. It is concluded that the ammonium ion influences carbohydrate metabolism chiefly by way of catecholamines and stimulation of α‐adrenergic receptors, while tissue lipids are mobilized by ammonia by another route, possibly directly.
THE EFFECT OF POTASSIUM CHLORIDE INFUSION ON PAROTID SALIVARY FLOW AND COMPOSITION IN CONSCIOUS SHEEP
Authors: Beal A. M. , Budtz‐Olsen O. E. , Clark R. C.
Published: December 2014

The composition and flow of parotid saliva in conscious sheep was measured before, during and after the intravenous infusion of 0·43 M‐KCl or 0·43 M‐NaCl at 2 ml./min for 2 hr. The salivary flow rate was depressed during the infusion of potassium chloride into both intact sheep and adrenalectomized sheep. As the salivary flow was unchanged by sodium chloride infusion it was concluded that the potassium ion was responsible for the decrease in flow and that this effect was not mediated through any of the adrenal hormones. The highly significant negative correlation between plasma potassium concentration and salivary flow throughout all potassium infusions indicated that the extent to which the salivary flow was depressed varied with the degree of hyperkalaemia. Except for situations where mineralocorticoid levels were likely to be elevated the concentrations of sodium and potassium in the saliva were positively co‐related with the plasma concentrations of these ions. The salivary bicarbonate concentration was positively correlated with the salivary flow whereas the phosphate concentration of the saliva was negatively related to flow. The chloride concentration of the saliva was negatively correlated with salivary flow during all potassium chloride infusions.
ULTRASTRUCTURAL CHANGES IN THE PLACENTA OF THE EWE FOLLOWING FOETAL INFUSION OF CORTISOL
Authors: Jack P. M. B. , Nathanielsz P. W. , Thomas A. L. , Steven D. H.
Published: December 2014

The placental changes which followed continuous infusion of cortisol into the sheep foetus in the later stages of gestation were, like the hormonal changes, broadly similar to those of spontaneous parturition. There was, however, a premature separation of foetal and maternal tissues in certain areas of the placental cotyledons, and this separation appeared to protect the foetal epithelium from the degenerative changes which normally take place in the short space of time between the birth of the lamb and the delivery of the foetal membranes. The results suggest that an experimental model in which premature labour is induced by the administration of cortisol to the foetus is probably incomplete, and that additional factors almost certainly contribute to the cascade phenomenon of spontaneous parturition.
PLASMA LIPOPROTEINS OF LAMBS AND SHEEP
Authors: Leat W. M. F. , Kubasek F. O. T. , Buttress N.
Published: December 2014

The major plasma lipoproteins of the adult sheep were high density lipoprotein (76%) having α‐mobility on electrophoresis and low density lipoprotein (20%) having β‐mobility. Chylomicrons and very low density lipoproteins were minor constituents (<5%). The postabsorptive hyperlipidaemia in suckling lambs is mainly a result of increased concentration of low density and high density lipoproteins although the relative contribution of very low density lipoproteins was increased to 7—15% of the total lipoproteins. The hyperlipidaemia was markedly greater in an intact male lamb than in female or castrated male lambs. In suckling lambs a new lipoprotein (density 1·090 g/ml) appeared in the high density lipoprotein fraction but disappeared before weaning.
ULTRASTRUCTURAL STUDIES OF THE PLACENTA OF THE EWE: PHAGOCYTOSIS OF ERYTHROCYTES BY THE CHORIONIC EPITHELIUM AT THE CENTRAL DEPRESSION OF THE COTYLEDON
Authors: Burton G. J. , Samuel Carole A. , Steven D. H.
Published: December 2014

Extravasated maternal blood, which escapes from capillaries and larger blood vessels within the tips of the maternal septa, is responsible for the characteristic pigmentation of the central depression of the ovine cotyledon in the last third of pregnancy. The chorionic epithelium of this region is actively engaged in the uptake and subsequent breakdown of maternal erythrocytes, which may represent an important source of iron for the foetus during the period of maximum intra‐uterine growth.
THE EFFECT OF INTRAVENOUS INFUSION OF HYPEROSMOTIC SODIUM AND POTASSIUM CHLORIDE SOLUTIONS ON CEPHALIC BLOOD FLOW IN CONSCIOUS SHEEP
Authors: Beal A. M.
Published: December 2014

The rate of flow of plasma and blood through the head of conscious sheep was measured before, during and after the intravenous infusion of 1 mol.l–1 NaCl and 1 mol.l–1 KCl at 0·8–1·0 ml. min‐1 for 2 hours. The plasma flow was estimated by indicator‐dilution technique using sodium para‐aminohippurate which was shown to be a satisfactory indicator substance. Short periods of rumination were found to cause marked increases in cephalic blood flow. The infusion of hyperosmotic sodium chloride caused no consistent changes in the rates of cephalic plasma flow and blood flow. During potassium infusion plasma and blood flows increased as the plasma potassium concentration increased up to approximately 6 mmol.l–1. Further increases in plasma potassium concentration were associated with a progressive return of these flow rates to or below the preinfusion levels. This pattern of change in the rate of plasma flow through the head of the sheep was very similar to that previously reported for renal plasma flow during hyperkalaemia in conscious sheep. At its maximum the cephalic plasma flow was 1·163±0·029 (S.E. of mean) times the pre‐infusion flow rate. Cephalic blood flow tended to reach maximum rates at slightly higher plasma potassium concentrations and thereafter, to fall more slowly than the plasma flow due to concomitant increases in haematocrit. Maximum cephalic blood flow was 1·176±0·032 times the preinfusion flow rate. The lowest rates of cephalic plasma and blood flow occurred during the first 30 minutes following cessation of potassium infusion.
THE PROJECTION OF THE RETINA, INCLUDING THE ‘RED AREA’, ON TO THE OPTIC TECTUM OF THE PIGEON
Authors: Clarke P. G. H. , Whitteridge D.
Published: December 2014

The optic tectum of the pigeon has been mapped physiologically, including much of the inferior surface. There are two separate regions of high magnification factor, the projection areas of the fovea and the middle of the red area in the retina, each of which has a correspondingly high density of neurones in the ganglion cell layer.
EFFECTS OF BRADYKININ MEDIATED BY AUTONOMIC EFFERENT NERVES
Authors: Floyd K. , Hick Verity E. , Koley Juthika , Morrison J. F. B.
Published: December 2014

Intra‐arterial injections of bradykinin cause increases in blood pressure and increased impulse rates in single sympathetic efferent fibres. The peptide also causes one or more large bladder contractions, which are associated with increased impulse rates in pelvic nerve efferent fibres whose spontaneous discharges are temporally associated with increases in intravesical pressure. These induced increases in pelvic nerve discharge and intravesical pressure could be abolished or greatly reduced by interference with conduction in pathways which mediate reflex bladder contractions. It is concluded that bradykinin has little direct action on the bladder, and that the large contractions which result from its administration are mediated by the central nervous system.
ADENOSINE TRIPHOSPHATASE LOCATED ON UNSTIMULATED HUMAN SMALL LYMPHOCYTE CELL MEMBRANES
Authors: Coulson A. S. , Zeitman V. H. , Cohn R. B. , Dong E. , Griepp R. B. , Stinson E. B. , Shumway N. E.
Published: December 2014

This study was undertaken to localize the enzyme sodium‐potassium dependent adenosine triphosphatase in unstimulated human small lymphocytes using the histochemical technique of McClurkin [1964]. The substrate adenosine 5' triphosphate is hydrolyzed by the ATPase resulting in a lead phosphate precipitate at the site of enzyme action, subsequently visualized as lead sulphide.

The enzyme was demonstrated in three different patterns, and for each donor the pattern was constant both on all four of the test slides, and on different occasions. The patterns observed were: clusters of granules related to the cell membrane; positive staining localized to portions of the cell membrane, and, less commonly, the whole cell circumference. The significance of this distribution may relate to areas with large numbers of antigen recognition sites on the lymphocyte membrane.
THE METABOLIC RESPONSE TO EXERCISE IN CHRONIC ALCOHOLICS
Authors: Chalmers R. J. , Sulaiman W. R. , Johnson R. H.
Published: December 2014

The metabolic response to steady exercise was studied in six chronic alcoholics and six normal control subjects. Higher concentrations of lactate and pyruvate were observed in the alcoholics during exercise and they also developed post‐exercise ketosis. These changes were probably not due to reduced fitness of the alcoholics as the heart rates of both groups were similar. Alcoholics had lower levels of growth hormone during exercise compared with the controls suggesting that chronic alcohol consumption has a depressor effect on pathways regulating the release of growth hormone.
VENTILATION, CARDIAC FREQUENCY AND PATTERN OF BREATHING DURING EXERCISE IN MEN EXPOSED TO O‐CHLOROBENZYLIDENE MALONONITRILE (CS) AND AMMONIA GAS IN LOW CONCENTRATIONS
Authors: Cole T. J. , Cotes J. E. , Johnson G. R. , de V. Martin H. , Reed J. W. , Saunders M. J.
Published: December 2014

Ventilation minute volume, tidal volume and cardiac frequency during submaximal exercise have been measured in healthy young soldier volunteers exposed to O‐chlorobenzylidene malononitrile (CS) and ammonia gas in concentrations respectively of 0·16 to 4·4 mg.m‐3 and 50 to 344 mg.m‐3. The response of ventilation minute volume to the two gases is apparently similar; both gases cause1 a reduction of, on average 6%. With low doses this reflects a diminution in respiratory frequency whereas with higher doses it is due to a reduction in tidal volume which is accompanied by tachypnoea.

The findings may result from stimulation successively of receptors in the larynx and of irritant receptors in the large airways of the lung. The pain which is a feature of exposure to CS but not to ammonia is due to stimulation of other so far unidentified receptors. Neither gas has a direct effect upon the exercise cardiac frequency.
THE EFFECTS OF REDUCING DIETARY NITROGEN AND OF INCREASING SODIUM CHLORIDE INTAKE ON UREA EXCRETION AND REABSORPTION AND ON URINE OSMOLALITY IN SHEEP
Authors: Ergene N. , Pickering E. C.
Published: December 2014

Renal responses to reducing dietary nitrogen were studied in four ewes during intravenous infusion of arginine vasopressin. The fall in urea excretion and in plasma urea concentration was accompanied by significant reduction in GFR and in urine osmolality. The fraction of filtered urea reabsorbed increased despite reduction in the urea U/P concentration ratio and this increase was sustained when the urea U/P ratio was further reduced at higher urine flows observed when the drinking water was replaced with saline. This procedure also sustained the RPF which in the absence of additional salt was significantly reduced on the low protein diet. It is suggested that the fall in GFR and the increase in the fraction of filtered urea reabsorbed may contribute to nitrogen economy and that the increase in fractional reabsorption and the reduction in urine osmolality on the low protein diet provided evidence of active reabsorption of urea by renal tubules.
THE ABSORPTIVE VIABILITY OF ISOLATED INTESTINE PREPARED FROM DEAD ANIMALS
Authors: Gardner Michael L. G.
Published: December 2014

Glucose and water absorption rates are much lower (50%) in isolated perfused rat small intestine when the animals are killed by stunning or ether before removal of the intestine than when the animal is maintained alive under light ether anaesthesia throughout the setting‐up procedure.