bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impairment of glycine absorption by glucose and galactose in man
Authors: Cook G. C. 
Published: December 2014

1. In order to investigate a possible competition for intestinal transport between amino acids and monosaccharides in man, iso‐osmotic solutions containing (A) 100 m‐mole glycine 1.−1, (B) 100 m‐mole glycine and 200 m‐mole monosaccharide (glucose or galactose) 1.−1, and (C) 200 m‐mole monosaccharide 1.−1, were successively perfused into the upper jejunum of twelve African Zambian patients. None had clinical evidence of malnutrition or small‐intestinal disease. By using a double‐lumen tube and by reference to a non‐absorbable marker (polyethylene glycol, 4000), the rates of absorption of these substances have been calculated for a 30 cm jejunal segment.2. The presence of glucose and galactose produced a significant impairment (up to 50%) in the rate of absorption of glycine. There was also a significant decrease in the uptake of both monosaccharides from the solutions in which glycine was also present.3. If this observation also applies to other amino acids it could have a practical value in population groups living on high carbohydrate diets with a marginal concentration of some essential amino acids. It could have special importance when the jejunal mucosa is damaged in severe malnutrition or gastrointestinal infection. This impairment of amino acid uptake may explain the very high incidence of genetically determined lactase‐deficiency in Africa.
Sustained and transient neurones in the cat's retina and lateral geniculate nucleus
Authors: Cleland B. G. , Dubin M. W. , Levick W. R. 
Published: December 2014

1. Cat retinal ganglion cells may be subdivided into sustained and transient response‐types by the application of a battery of simple tests based on responses to standing contrast, fine grating patterns, size and speed of contrasting targets, and on the presence or absence of the periphery effect. The classification is equivalent to the ‘X’/‘Y’ (linear/nonlinear) subdivision of Enroth‐Cugell & Robson which is thus confirmed and extended.2. The sustained/transient classification applied to both on‐centre and off‐centre cells.3. Lateral geniculate neurones may be similarly classified by the same tests. Occasional concentrically organized cells had a mixture of sustained and transient properties.4. A technique for simultaneous recording from a geniculate neurone and one or more retinal ganglion cells providing its excitatory input showed that the connexions were specific with respect to the sustained/transient classification as well as the on‐centre/off‐centre classification. Most geniculate neurones are excitatorily driven only by retinal ganglion cells of the same functional type. In a few cases the inputs were mixed but only with respect to the sustained/transient classification.5. Sustained retinal ganglion cells had slower‐conducting axons than the transient type. The same was true for lateral geniculate neurones but in this case the distributions showed considerable overlap.6. The sustained/transient classification is the functional correlate for the well‐known segregation of optic nerve fibres into two conduction groups.7. The pathways carrying sustained and transient information remain essentially separate from retina through the lateral geniculate nucleus to the striate cortex.
The mechanics of sprint running
Authors: Cavagna Giovanni A. , Komarek L. , Mazzoleni Stefania 
Published: December 2014

1. The effect of the velocity of shortening on the power developed by the muscles in sprint running was studied by measuring the mechanical work done to accelerate the body forward from the start to about 34 km/hr.2. The work was measured at each step from the data obtained by means of a platform sensitive to the force impressed by the foot.3. Almost the totality of the positive work done during the first second from the start is found as an increase of the kinetic energy of the body. However, as the speed of the run rises, air resistance and particularly the deceleration of the body forward, taking place at each step, rapidly increase, limiting the speed of the run.4. The average power developed by the muscles during the push at each step increases with the velocity of running reaching 3‐4 h.p. at the maximal speed attained.5. At low speed the contractile component of the muscles seems to be mainly responsible for the power output, whereas at high speed (25–34 km/hr) an appreciable fraction of the power appears to be sustained by the mechanical energy stored in the ‘series elastic elements’ during stretching the contracted muscles (negative work) and released immediately after in the positive work phase.
Noradrenaline and acetylcholine responses of supraoptic neurosecretory cells
Authors: Barker J. L. , Crayton J. W. , Nicoll R. A. 
Published: December 2014

1. Neurones in the supraoptic nucleus were examined for their responsiveness to microiontophoretically applied monoamines and cholinomimetic agents. One hundred and sixty‐one of the 749 neurones recorded were antidromically identified as neurosecretory cells.2. The monoamines, dopamine, noradrenaline and serotonin, reduced the activity of all cells which responded.3. Reduction in activity following noradrenaline administration was antagonized by the β‐adrenergic blocking agent MJ‐1999 and potentiated by desmethylimipramine.4. Acetylcholine produced either a decrease or an increase in activity of responsive cells with depression the predominant result. Both the depressant and the excitatory response to acetylcholine were seen in individual neurosecretory cells which were depressed by noradrenaline.5. Application of acetyl‐β‐methylcholine and carbaminoylcholine consistently resulted in depression of all responsive cells, while nicotine excited the majority of responsive cells. Both types of response were observed on the same neurosecretory cell.6. The depressant response was antagonized by the muscarinic blocking agent atropine while the excitatory response was antagonized by the nicotinic blocking agent dihydro‐β‐erythroidine. Responses to acetylcholine were potentiated by the acetylcholinesterase inhibitor physostigmine.7. The data indicate that noradrenaline‐containing terminals on these neurosecretory cells are likely to inhibit their discharge rate, while the presumed cholinergic terminals might function as either excitatory or inhibitory, depending on the receptor activated.8. These results support the hypothesis that ADH release is related to the neuronal activity of the supraoptic neurosecretory cell.
Changes of sodium and urea concentrations in the renal papillary interstitial fluid on dehydration of rats
Authors: Lee J. , Williams P. G. 
Published: December 2014

1. The isolated renal papillae of a rat were centrifuged in a two tube assembly which allowed fluid from the tissue to separate into the lower tube.2. The papillae were centrifuged for 15 min at 300 g and 1500 g consecutively.3. After intraperitoneal injection of Na 131I‐diatrizoate, the activities of urine, and fluid samples obtained from the papilla, were compared. It was found at 1500 g that the median value for papillary fluid activity was 1·52% of the activity of urine. This is evidence that the papillary fluid was virtually free from any contamination from the terminal collecting ducts.4. It is considered that the fluid sample obtained from the papillae by centrifugation at 1500 g is a representative and reproducible sample of interstitial fluid.5. The method was used to demonstrate changes in solute concentrations in the renal papillary fluid, following dehydration of rats.
Effects of descending impulses on transmission through the spinocervical tract
Authors: Brown A. G. 
Published: December 2014

1. Micro‐electrode recordings were made from ascending axons of the spinocervical tract in unanaesthetized decerebrate cats before, during and after reversible cold block of impulse conduction in the spinal cord rostral to the recording site.2. Most units (forty‐one of forty‐four) fell into one of four categories as defined by their evoked responses to mechanical stimulation of identified cutaneous receptors. These categories were; Type I excited by movement of tylotrichs (hairs) in the decerebrate preparation but by movement of all types of hairs after block of descending impulses; Type II excited by movement of guard hairs and usually weakly by pressure in the decerebrate state but by movement of all types of hairs and by pressure in the spinal state; Type III excited by movement of all types of hairs and often by pressure in the decerebrate animal but by movement of all types of hairs and always by pressure in the spinal animal; Type IV weakly excited by heavy pressure or with no receptive field in the decerebrate state but excited by pressure in the spinal state.3. The descending influences depressed the spontaneous activity and the evoked responses to harmful stimuli.4. The descending influences depressed inhibitory inputs from segmental levels.5. The functional significance of the descending control is discussed.
The effect of intravenous infusion of antidiuretic hormone on water intake in the rat
Authors: Rolls Barbara J. 
Published: December 2014

1. In rats the continuous
I.V. infusion of ADH at rates up to 6·0 mu. kg−1 min−1 decreased drinking caused by water deprivation, by a 10% increase in osmotic pressure, and by caval ligation.2. Infusion of ADH at rates between 0·07 and 6·0 mu. kg−1 min−1 never potentiated drinking nor did it significantly affect the 24 hr water intake of rats that were in water balance at the start of the experiment.3. Urine output was slowed by a rate of infusion (13·0 μu. kg−1 min−1) which was approximately 150 times smaller than the lowest rate which was found to decrease water intake.4. Since the rates of infusion of ADH which directly affect water intake and urine flow are so different, it is unlikely that ADH is a general homoeostatic hormone which controls both thirst and urine output in the rat.
The secretory nerves of the parotid gland of the dog
Authors: Holmberg Jan 
Published: December 2014

1. Secretory nerve fibres to the parotid gland of the dog have been found in the adventitia of the internal maxillary artery. In dogs under chloralose anaesthesia the course of these fibres from the mandibular nerve to the gland was determined by electrical stimulation at different sites. Secretion induced by these nerves was abolished by atropine but not by hexamethonium.2. In dogs in light barbiturate anaesthesia parotid secretion was evoked reflexly by pouring citric acid on the tongues. After division of the auriculo‐temporal nerve and the nerves on the artery this secretion disappeared in about half the experiments and was greatly reduced in the others.3. The maximal secretory rate which could be obtained reflexly from the normally innervated parotid gland was first estimated in light barbiturate anaesthesia. Chloralose was then given and the auriculo‐temporal nerve and the nerves on the artery were electrically stimulated together; in about half the experiments this could produce secretion at a rate as high as that obtained reflexly.4. By separate and simultaneous stimulation of different sets of nerve fibres convergence of the secretory fibres to the glandular cells could be demonstrated.5. It is concluded that a large number of post‐ganglionic, cholinergic secretory fibres to the canine parotid gland run on the internal maxillary artery. In some dogs a small number of fibres seem to have escaped detection. Possibly they may reach the gland by way of the facial nerve.
The locations and activities of medullary neurones associated with ruminant forestomach motility
Authors: Harding R. , Leek B. F. 
Published: December 2014

1. Neuronal activity bearing a temporal relationship with spontaneous reticulo‐ruminal movements was recorded with micro‐electrodes from the medulla oblongata in halothane‐anaesthetized sheep. Recording sites were located histologically after causing electro‐coagulation at the micro‐electrode tip.2. One hundred and forty‐four gastric units were recorded from the dorsal vagal nucleus and up to 1 mm dorsal and lateral to the nucleus between transverse planes 1 mm caudal, and 4 mm rostral, to the obex. It is considered that records were obtained from the regions of cell bodies.3. The discharges of thirty‐two vagal preganglionic motoneurones were identified by an antidromic collision technique. Conduction velocities ranged from 10–26 m/sec. They were located in the dorsal vagal nucleus and up to 0·5 mm dorsal and lateral to the nucleus. The majority of motoneurones innervated either the reticulum or the rumen. One ruminal unit discharged during both primary and secondary cycle movements.4. One hundred and twelve units which were not orthodromically or antidromically activated by stimulating the vagus nerves were considered to be interneurones. Four types were distinguishable on the basis of their patterns of discharge during primary cycle movements.5. The discharges of Type A interneurones resembled those of gastric motoneurones, having no resting discharge between contraction cycles. Their discharges were temporally related to either reticular contractions or rumen contractions during primary and secondary cycle movements.6. Types B and C interneurones have resting discharges which, respectively, increased and either decreased or stopped during each primary cycle movement.7. Discharges of only three units identified as interneurones resembled the discharges of gastric vagal afferent units.
Respiratory movements and rapid eye movement sleep in the foetal lamb
Authors: Dawes G. S. , Fox H. E. , Leduc B. M. , Liggins G. C. , Richards R. T. 
Published: December 2014

1. In foetal lambs from 40 days gestation (0·27 of term) onwards delivered into a warm saline bath, apparently spontaneous breathing movements were present intermittently. They became deeper and more rapid with increasing age.2. In foetal lambs (from 0·66 of term) in which observations were made for many days after chronic implantation of tracheal, carotid and amniotic catheters, rapid irregular respiratory movements were present up to 40% of the time, and brief gasps also were seen.3. The presence of these movements was unrelated to the foetal carotid blood gas values over a wide range of spontaneous variation.4. These foetal breathing movements were accompanied by comparatively small alterations of pulmonary volume recorded from a tracheal flowmeter, insufficient to clear the tracheal dead space. Occasionally a more prolonged expiration led to the outward flow of fluid.5. A description is given of sleep and wakefulness in foetal lambs from 0·78 of term.6. Rapid irregular breathing was associated with rapid eye movement sleep as seen in a warm saline bath or, in utero, as inferred from records of eye movements and electrocortical activity.7. Respiratory movements were often associated with relatively large variations in foetal heart rate, blood pressure and descending aortic blood flow.8. Rapid irregular foetal breathing was unaffected by section or blockade of the cervical vagi, but was abolished by general anaesthesia.9. It is concluded that respiratory movements are normally but intermittently present in the foetal lamb over the greater part of gestation.
Sympathetic inhibition of the urinary bladder and of pelvic ganglionic transmission in the cat
Authors: de Groat William C. , Saum William R. 
Published: December 2014

1. Electrophysiological techniques were utilized to study the mechanisms underlying adrenergic inhibition in the urinary bladder of the cat.2. It has been shown that catecholamines administered by close intraarterial injection or released endogenously by electrical stimulation of the hypogastric nerves elicit two distinct inhibitory responses in the bladder: (1) a direct depression of the vesical smooth muscle and (2) a depression of transmission in vesical parasympathetic ganglia.3. Pharmacological studies revealed that the inhibitory mechanisms were mediated via different adrenergic receptors: β‐receptors on the smooth muscle and α‐receptors in the parasympathetic ganglia.4. We have been unable, however, to demonstrate that either of these mechanisms is activated by naturally occurring sympathetic firing.
Radio‐immunoassay of gastrin in human plasma
Authors: Ganguli P. C. , Hunter W. M. 
Published: December 2014

1. A radio‐immunoassay for gastrin has been developed using partially purified porcine gastrin to raise antibodies and highly purified natural porcine gastrin I for radio‐iodination with 125I. The separation of antibody‐bound from free hormone was performed by a double‐antibody method.2. In this assay highly purified natural porcine gastrin I, synthetic human gastrin I, radio‐iodinated porcine gastrin I, gastrin in the plasma of a healthy volunteer, a patient with pernicious anaemia and another patient with the Zollinger—Ellison syndrome were immunologically identical.3. The fasting plasma gastrin concentration of fourteen gastric ulcer patients was significantly higher than that of the 113 hospital controls with no history of gastro‐intestinal disease, while twenty‐seven duodenal ulcer patients had gastrin levels within the normal range.4. Plasma gastrin concentration was significantly elevated in pernicious anaemia (fifty‐one patients), achlorhydria (thirty‐three patients), hypochlorhydria (eleven patients) and in nine patients with histologically proven Zollinger‐Ellison syndrome.5. In human volunteers a protein meal stimulated endogenous gastrin release while a carbohydrate meal did not. Atropine sulphate
I.M., and hydrochloric acid orally, produced a significant fall in the level of circulating gastrin.
The metabolic basis to the fluid pump in the cornea
Authors: Dikstein S. , Maurice D. M. 
Published: December 2014

1. A technique for isolating and perfusing the rabbit cornea is described, which allowed its thickness to be continuously measured under the microscope. The reversal of thickness of the cold‐swollen cornea on perfusion with various solutions at 37° C was studied.2. It was found that only a combination of adenosine and glutathione was able to reliably reverse the thickness to its normal value. This mechanism is sodium, bicarbonate, and oxygen dependent. Inhibitors of glycolysis or electron transport stop the reversal process.3. The findings are consistent with a need for an ATPase but are not capable of distinguishing among several possibilities for its regulation.
Characteristics of spinal neurones responding to cutaneous myelinated and unmyelinated fibres*
Authors: Gregor M. , Zimmermann M. 
Published: December 2014

1. Spike discharges were recorded from neurones in the lumbar spinal cord in cats anaesthetized by barbiturate.2. The neurones were examined systematically for various physiological parameters and for their location. Especially the neurones situated in the dorsal horn were classified for the following parameters: mono‐ or polysynaptic linkage to myelinated afferents; type of natural stimuli which excited the neurones; depth from the cord surface; number of impulses discharged upon a cutaneous A fibre stimulus; steady‐state discharge in the absence of intentional stimulation.3. All neurones were also tested as to whether or not they responded to volleys in cutaneous C fibres. Of 111 units which were activated by the A fibres in nerves from the hairy skin, 57 (= 51%) responded to C volleys in those nerves too.4. By blocking conduction in the A fibres using polarizing currents it was shown that the responses to C fibre volleys were partially or totally suppressed by a preceding discharge of the neurone in response to an A volley. Using search stimuli which were suprathreshold for C fibres one cell out of 36 could be found which responded only to afferent volleys in C fibres.5. About half of all neurones were shown to be connected monosynaptically to cutaneous A fibres, as was judged from the synaptic delay. The other half were polysynaptically linked to the A fibres. Both mono‐ and polysynaptic neurones were found in all layers of the dorsal horn. About 15% of the cells had additional input from muscle Group II and/or III fibres via polysynaptic pathways.6. Subdividing the A and A+C responsive neurones according to their mono‐ (M) or polysynaptic (P) connexions yielded the following sub‐samples: MC, 39%; PC, 15%; MA, 13%; PA, 33%. Most MC neurones had, and most PA units had not, a spontaneous discharge. About half of the PA cells could not be driven by natural skin stimulation. The majority of MC units responded specifically to movement of hairs.7. A model was proposed hypothesizing two pathways in the dorsal horn, one showing convergence of A and C fibres and the other not. Some relations concerning other observations on C fibre effects were discussed.
Reversible differential block of saphenous nerve by cold
Authors: Byck R. , Goldfarb J. , Schaumburg H. H. , Sharpless S. K. 
Published: December 2014

1. This report is concerned with the question of whether the alpha and delta groups of myelinated A fibres show conduction failure at different temperatures.2. The experiments were done on cat saphenous nerve in vitro. Stimuli were applied to both ends of the nerve and biphasic recordings were taken adjacent to an 11 mm segment of nerve, whose temperature was varied. Before cooling commenced, the stimuli were adjusted so that the action potential which passed through the cold zone and was recorded, collided with the action potential initiated at the opposite end of the nerve.3. Upon cooling the nerve, it was always observed that the delta peak of the action potential which had been previously occluded by collision reappeared at a temperature at which the alpha peak remained occluded.4. The reappearance of the delta peak was reversible upon warming the nerve and was not affected by increasing the interstimulus interval.5. The mean temperature for reappearance of the delta peak was 13·5° C, for reappearance of the alpha peak, 5·3° C.6. In any given nerve, the blocking temperature was replicable and was dependent on the temperature of the cooled segment rather than the gradient between that segment and the remainder of the nerve.7. We conclude that in cat saphenous nerve, the delta group of myelinated A fibres shows conduction failure at a higher temperature than does the alpha group.
The visibility and fading of thin lines visualized by their controlled movement across the retina
Authors: Sharpe C. R. 
Published: December 2014

1. The entoptic shadows of the retinal blood vessels were visualized by temporal modulation of their contrast.2. For perception of fine detail, the shadows must move successively from one photoreceptor to the next. To see coarser detail the contrast need only be temporally modulated.3. The contrast threshold of the pattern of shadows rises steadily as they are viewed until the shadows can no longer be seen even with the highest contrast available.4. This elevation of contrast threshold is partially binocularly transferred, suggesting that the perceptual fading has a central origin.5. The fading of the shadows is specific for their orientation, direction of movement and their width.6. Image movements like those produced by fixational eye movements have been simulated. The shadows still fade; the results can be explained in terms of spatial adaptation (Blakemore & Campbell, 1969) of spatial frequency and orientation channels.