bluuebunny/crossref_metadata_2025_split huggingface dataset:
INACTIVATION OF HISTAMINE AND OCCURRENCE OF SMOOTH MUSCLE STIMULATING ACTIVITY IN PLASMA OF SHEEP
Authors: Sjaastad Ö. V. 
Published: December 2014

With incubation periods of 90 min., histamine inactivation in sheep plasma was nearly proportional to substrate concentration within the range of 2 to about 50 µg. histamine diphosphate/ml. plasma. Increasing the substrate concentration above 80 µg./ml. did not increase the histamine inactivation. At optimal substrate concentrations (80 µg./ml. plasma), a histamine inactivating capacity of 42·1±4·8 µg. histamine diphosphate/ml. plasma/hr. was found in seventeen sheep examined. About 80 per cent of the histamine inactivation was abolished by aminoguanidine, indicating that oxidative deamination is the major route of inactivation in sheep plasma in vitro.When plasma was incubated for more than 60 min. with an initial histamine concentration less than 20 µg./ml., smooth muscle stimulating activity interfering with the biological determination of histamine, was observed. Such activity developed rapidly when glass powder was added to plasma prepared with siliconized equipment and it is concluded that the interfering activity is due to substance(s) resembling bradykinin.
DAILY RHYTHMS OF RENAL EXCRETION IN ARCTIC‐DWELLING INDIANS AND ESKIMOS
Authors: Lobban Mary C. 
Published: December 2014

The daily rhythms of renal excretion of indigenous arctic subjects were recorded under natural conditions during the continuous midsummer daylight (Indians and Eskimos) and in the continuous darkness of midwinter (Indians only). The excretory patterns for water, potassium, sodium and chloride have been compared with those of a group of British control subjects, recorded when they were newly introduced into a summer arctic environment in adult life. In general, the excretory patterns of the arctic subjects contain a high proportion of abnormalities, such that the averaged patterns for the indigenous groups are less well defined than are those for the control group of subjects from a temperate zone. The loss of definition of the rhythms is most marked in the Eskimo subjects, where differences between day and night excretory rates have virtually disappeared.Mathematical analysis of the individual results shows that the relative amplitude of the rhythm of potassium excretion decreases from British controls → summer Indians → winter Indians → summer Eskimos. The differences between control subjects and all indigenous subjects and between Indians and Eskimos are significant, and cannot be accounted for by variations in age, activity pattern or diet.It is suggested that the normal daily alternation of light and darkness in the environment is important not only for the day‐to‐day maintenance of renal diurnal rhythms but also for the initiation and full expression of these rhythms in the early life of the human subject.
MOTONEURONE ACTIVITY AS A CAUSE OF DEGENERATION IN THE SOLEUS MUSCLE OF THE RABBIT
Authors: McMinn R. M. H. , Vrbová G. 
Published: December 2014

The tenotomized soleus muscle of a spinal rabbit does not degenerate unless it is stimulated electrically. If the muscle is stimulated at a frequency of 10 imp./sec., the histological changes occurring resemble those of tenotomized muscles in animals without spinal cord section.No decrease of tension can be found if untenotomized muscles of spinal rabbits are stimulated, indicating that no degeneration is taking place.It is concluded that isotonic contractions without a load are harmful to the structural integrity of the slow soleus muscle.
ALBUMIN, TRANSFERRIN AND GAMMA‐GLOBULIN METABOLISM DURING LACTATION IN THE RAT
Authors: Jordan Susan M. , Morgan E. H. 
Published: December 2014

The turnover of rat serum albumin, transferrin and γ‐globulin and their transfer to the milk was studied following injection of radioiodine‐labelled purified proteins to rats on the 2nd, 9th and 17th days of lactation. The concentrations of the three proteins were also measured in maternal serum, milk whey and the serum of the suckling young.The concentrations and relative and absolute rates of turnover of each protein in maternal serum changed very little with progression of lactation. The concentration of transferrin in whey increased greatly as lactation progressed, while the concentrations of the other two proteins remained constant. The ratio of whey protein‐bound radioactivity to maternal serum activity was constant for each protein at the three stages of lactation. The specific activity of whey albumin and γ‐globulin also remained constant at 100 and 85 per cent respectively of the maternal serum values, while the transferrin specific activity fell from 100 per cent the maternal serum value in early lactation to 25 per cent of this value late in lactation.It is concluded that all of the albumin and most of the γ‐globulin of rat whey is derived from the blood plasma, while an increasing amount of transferrin up to 75 per cent in late lactation, and a little γ‐globulin is synthesized in the mammary gland.
OBSERVATIONS ON THE COURSE OF THE METABOLIC EVENTS ACCOMPANYING MILD EXERCISE
Authors: Harris P. , Bateman M. , Bayley T. J. , Donald K. W. , Gloster J. , Whitehead T. 
Published: December 2014

The ventilation and the oxygen uptake rise during the first 5 min. of mild exercise, remain at a new high level until the end of exercise, and then fall again during the succeeding 5 min. The response of the ventilation and the oxygen uptake are, therefore, similar to the output of a simple damped system in the presence of a square‐waved input.The metabolic response is considerably more complex than the respiratory. This is not only because of the divergent changes of many different substances, but also because these changes arise at specifically different times during the course of events.There appear to be three major groups of disturbances of the composition of the blood accompanying exercise ‐ one group associated with beginning of exercise, one group which is maintained throughout exercise, and one group which is specifically associated with the period of recovery.During the first 5–15 min. after the beginning of exercise there is an increase in the concentration of lactate and pyruvate, the latter reaching its maximum about 5 min. after the former. The increased concentration of lactate is associated with a fall in pH and standard bicarbonate. At the same time there is a transient fall in the free fatty acids in the plasma. All these phenomena also accompany exercise of shorter duration, in which case they continue to evolve after exercise has stopped and the concentration of lactate remains high long after the oxygen uptake has returned to its initial resting level.More prolonged exercise reveals a number of disturbances which would seem to continue indefinitely during the period of exertion. These consist of a certain degree of elevation of the concentration of lactate and pyruvate, and of the serum potassium, sodium and inorganic phosphorus. The concentration of free fatty acids is maintained at a level at or a little above that which existed before exercise. The concentration of glucose is not greatly affected.Immediately after the end of prolonged exercise, the concentration of lactate declines, although, in mild exercise, this usually appears to be a continuation of a process which had already started during exercise. By contrast, during the first few minutes of recovery, the concentration of pyruvate usually shows a transient increase which is followed by a more sustained fall. The concentrations of potassium, sodium and phosphorus fall again at this time, and there is evidence from the literature that a sustained and substantial fall in phosphorus may occur. Immediately after the end of excercise, there is an increase in the concentration of glucose and free fatty acids which may be of considerable magnitude and duration.
THE INTESTINAL AND HEPATIC CONTRIBUTIONS TO THE FLOW AND COMPOSITION OF THORACIC DUCT LYMPH IN YOUNG MILK‐FED CALVES
Authors: Shannon A. D. , Lascelles A. K. 
Published: December 2014

The establishment of recirculating lymphatico‐venous shunts permitted the repeated collection of lymph from either the thoracic or intestinal duct in healthy calves. Hepatic lymph was also collected from calves with lymphatic fistulæ. The operations were carried out on calves in the first week of life.The mean flow of thoracic duct lymph from four calves was 9·73 ml./kg./hr., of intestinal lymph from three calves 8·25 ml./kg./hr. and of hepatic lymph from two calves 0·64 ml./kg./hr. During the experiment the calves were fed 2·27 litres (0·5 gal.) of cow's milk twice daily. The mean protein concentration of lymph from the thoracic, intestinal and hepatic ducts was 56·5, 56·7 and 80·6 per cent, respectively, of the plasma levels. Thus the intestinal lymph contributed most of the volume of lymph and output of protein from the thoracic duct. It was estimated that 275 and 330 per cent of the volume and 155 and 190 per cent of the total protein of the blood plasma compartment passed through the intestinal and thoracic ducts, respectively, in a 24‐hr. period.There was a rapid transfer of T‐1824‐labelled albumin from plasma into intestinal and hepatic lymph in the young calf. Equilibration of the specific activity curves for plasma and for intestinal and hepatic lymph occurred within 100 min. after the injection of the T‐1824.The lipid composition of intestinal lymph was found to be very similar to that of thoracic duct lymph. The concentrations of triglyceride and free fatty acid in hepatic lymph were 350 and 170 per cent, respectively, of those in plasma. It is suggested that a triglyceride‐rich component and free fatty acid were released from the liver into the hepatic lymph.The high flow and output of protein from the intestinal duct may be related to the absorption of large quantities of fat in young milk‐fed calves.
THE ANTAGONISM OF Ca2+ BY Na+ AND OTHER MONOVALENT IONS AT THE FROG NEUROMUSCULAR JUNCTION
Authors: Kelly J. S. 
Published: December 2014

The quantal content of the e.p.p. and the frequency of the m.e.p.p.s in the presence of enhanced extracellular K+ have been investigated by intracellular recording from frog sartorius muscle fibres. In the presence of 0·23 mM Ca2+ (one eighth of the normal), the replacement of NaCl by sucrose or glycine led to a large increase in quantal content; the size of this increase appeared to be related to the amount of NaCl replaced. The quantal content in 0·9 mM Ca2+, however, was not appreciably altered by the replacement of NaCl by sucrose. When LiCl was used to replace NaCl, the immediate change in the quantal content was small. With methyl‐ and ethylammonium or tris chlorides as substitutes for NaCl, the immediate effect was a reduction in quantal content. A delayed effect of LiCl was a reduction, and that of methylammonium an increase, in quantal content. The replacement of NaCl by sucrose accelerated the m.e.p.p. frequency in the presence of enhanced K+ (12 mM); in contrast the replacement of NaCl by methylammonium chloride caused a reduction in frequency. With LiCl as a substitute the frequency of the m.e.p.p.s increased in the normal K+ concentration, the increase being slowly reversible in the normal Ringer solution.It is suggested that antagonism of Ca2+ by Na+ is non‐specific and that other monovalent cations will also compete with Ca2+.
ABSORPTION OF VOLATILE FATTY ACIDS, TRITIATED WATER AND ANTIPYRINE FROM THE ABOMASUM OF GOATS
Authors: Engelhardt W. v. , Ehrlein H. ‐J. , Hörnicke H. 
Published: December 2014

In conscious goats the abomasum was isolated temporarily from the rest of the gastro‐intestinal tract by means of balloons, or a double by‐pass or a snare around the pylorus. Abomasal contents, rumen fluid or a saline solution were given into the abomasum. Altogether forty experiments were done on four goats.The absorption of acetic acid, propionic acid, butyric acid, tritiated water (HTO) and antipyrine (AP) from the abomasum was measured. For comparison of the absorption rates, the data were given as clearance of the abomasal fluid and as water diffusion.At a mean abomasal fluid volume of 606 ± 201 ml., 513 ± 169 ml. water diffused out of the abomasum through the abomasal mucosa per hour. The antipyrine clearance was 214 ± 84 ml./hr. The volatile fatty acids (VFA) were absorbed considerably faster at acid than at neutral pH values; at pH 5·2 — 5·6 the VFA clearance was only 320 ml./hr.: at pH 3·5−4·0, however, it increased to 1130 ml./hr.The olive oil: water partition coefficients for acetic, propionic and butyric acid were measured in the pH range of 3·5 −6·2. With decreasing pH values the degree of dissociation of the acids decreases and the lipid solubility increases considerably. The permeability of the abomasal and ruminal mucosa for VFA also increases at lower pH values, but not as much as the olive oil : water partition coefficients of the acids.Absorption of VFA, HTO and AP from the abomasum is discussed in relation to the absorption of these substances from the rumen and the human stomach.
THE EFFECT OF ENVIRONMENTAL TEMPERATURE ON HEALING OF BONE LESIONS IN THE RAT. II. THE EFFECT OF BONE INJURY ON MINERAL METABOLISM AT 20° C. AND 30° C
Authors: Cuthbertson D. P. , Tilstone W. J. 
Published: December 2014

Fracture of a radius in rats living at 20° C. and 300° C. leads to a greater whole‐body retention by both groups of a tracer dose of 85Sr injected at the time of fracture, compared to the whole‐body retention found in isothermally housed uninjured controls. A simple small dental drill‐hole lesion of the tibia resulted in an enhanced whole‐body retention of tracer only in rats living at 300° C.There is evidence of skeletal mobilization of calcium on fracture of a bone in rats at 20° C., but not in those at 30° C. However, there were no histologically observable differences in healing of bone lesions between the two groups of rats.
THE PERMEABILITY TO 131I‐PVP OF THE NORMAL AND HYPERTROPHIED GASTRO‐INTESTINAL TRACT OF SHEEP
Authors: Fell B. F. , Regoeczi E. , Campbell Rosa M. , Mackie W. S. 
Published: December 2014

The permeability to 131I‐PVP of the gastro‐intestinal tract was studied in non‐breeding ewes, in post‐parturient ewes with alimentary hypertrophy, and in post‐weaning ewes in which the enlarged intestines were undergoing involution. A method for measuring the clearance of 131I‐PVP from the plasma by the gastro‐intestinal tract is presented and is shown to be more sensitive than that of expressing faecal radioactivities as a fraction of the intravenous dose.The clearance of 131I‐PVP by the gastro‐intestinal tract in non‐breeding ewes was 4·29 per cent of the total clearance from the blood; during the development of alimentary hypertrophy the clearance was 5·09 per cent, and in a group with maximum hypertrophy, 4·91 per cent. These increases were not statistically significant (P〉0·01, but 〈0·05), but the mean clearance value of 6·81 per cent during the atrophy of the intestinal mucosa was significantly higher than the corresponding value in any other group (P〈0·01).The clearance of 131I‐PVP from the plasma via the bile and pancreatic secretions in two normal sheep was equal to about 2 per cent of the total plasma clearance of PVP.It is concluded that the increase in permeability during the post‐weaning atrophic phase of the gut is probably insufficient to cause marked alterations in the catabolism of plasma proteins. The half‐life of serum albumin was measured in both lactating and non‐breeding ewes, and the conclusion that gastro‐intestinal hypertrophy in the lactating ewe is not accompanied by a significant increase in permeability to macromolecules is supported by the finding that the half‐life of serum albumin is not affected by lactation.
ACTION OF OXYTHIAMINE AND PYRITHIAMINE ON THE ISOLATED RAT SUPERIOR CERVICAL GANGLION
Authors: Perri V. , Sacchi O. , Casella C. 
Published: December 2014

Incubation of isolated preparations of the superior cervical ganglion of the rat in the presence of low concentrations of oxythiamine and pyrithiamine results in an early and pronounced decrease of the post‐ganglionic potential. This effect is particularly evident with regard to oxythiamine.The depressant action of both antithiamines on ganglion transmission appears to be specifically due to their metabolic competition because it can be completely prevented by the presence of equimolecular amounts of thiamine in the incubating medium.
THE RAT HEPATOCYTE AFTER EXPOSURE TO HIGH ALTITUDE: STRUCTURAL AND CHEMICAL CHANGES
Authors: Burgos M. H. , Zangheri E. O. , Parisii I. M. 
Published: December 2014

One‐day‐old rats were exposed for 2 weeks in a low pressure chamber at a simulated altitude of 4,700 m. Then total esterified fatty acids, phospholipids and glycogen were determined in their livers, and electron microscopy of the liver cells was carried out. Normal rats of the same age were examined as controls. In the rats exposed to simulated high altitude, total esterified fatty acids were more than thrice the control value, phospholipid the same as the control value, and glycogen less than the control value. Their hepatocytes showed a marked increase in cytoplasmic lipid droplets, most pronounced near the central vein of the hepatic lobules; a marked diminution in rough endoplasmic reticulum; and generally absence of glycogen particles. Dense mitochondria of normal appearance were seen very closely apposed to the lipid droplets.Altitude appears to interfere with the normal development of the hepatocyte, which remains in a rather enzymatically immature stage.
OBSERVATIONS ON THE ‘SURROUND’ PROPERTIES OF THE RECEPTIVE FIELDS OF FROG RETINAL GANGLION CELLS
Authors: Keating M. J. , Gaze R. M. 
Published: December 2014

The activity of frog retinal ganglion cells has been studied, using metal filled micropipette electrodes and recording the activity in either the optic nerve or the superficial neuropil of the optic tectum. It is a feature common to all such cells that their activity can be modulated by retinal stimulation of an area surrounding the excitatory receptive field (ERF).It has been demonstrated that the inhibitory ‘surround’ for sustained edge units (class 1 and 2) is considerably larger than previously realized, extending up to 45° from the edge of the ERF.An inhibitory surround to the receptive fields of ‘on’ units has been demonstrated. In addition an unsuspected complexity of the surround organization of dimmer units (class 4) has been found.
THE ISOLATED PERFUSED LIVER OF THE SHEEP: AN ASSESSMENT OF ITS METABOLIC, SYNTHETIC AND EXCRETORY FUNCTIONS
Authors: Linzell J. L. , Setchell B. P. , Lindsay D. B. 
Published: December 2014

A technique is described for perfusing in isolation the livers of Soay sheep. Thirty‐two livers were perfused for 3–8·5 hr and their normality assessed by histology and by measuring blood and bile flow, Bromsulphthalein (B.S.P.) clearance, the uptake of O2 and infused NH3 and propionate, the production of CO2, urea and glucose and changes in tissue glycogen and weight. With portal pressure set below 10 mm Hg and arterial pressure set at l10 mm Hg, blood flow was 90–400 ml./100 g/min, 3–35 per cent of which came from the hepatic artery. Stimulation of nerves around the hepatic artery caused vasoconstriction in hepatic and portal vascular beds. Maximum bile flow during perfusion was similar to pre‐perfusion values, but generally declined to 20–75 per cent. The extraction of B.S.P. from the blood was inversely related to total blood flow, but directly to the hepatic artery flow. The percentage of injected B.S.P. appearing in the bile was related to bile flow. Perfused livers appeared normal histologically but small amounts of GOT (aspartate amino transferase) were released into the perfusate continually. O2 consumption averaged 1·8 ± 0·21 ml./min/100 g liver with no substrate added to the perfusate and 3·28 ± 0·28 when ammonium propionate was added. Liver glycogen generally (but not invariably), fell during perfusion. Glucose and urea outputs were greatly stimulated by the addition of ammonium propionate to the perfusate, and carbon from 14C propionate was transferred to glucose and CO2. The maximum rate of glucose production from propionate was comparable to that attained in the intact animal, but urea production from ammonia was less than values for the entry rate of urea into the circulation, from all sources, reported in the intact animal.The sheep liver, even when taken from a shot animal, appears to perfuse as well as rat or dog liver, and should be a useful preparation for studying gluconeogenesis and liver function in ruminants.
WATER, SODIUM AND POTASSIUM MOVEMENTS ACROSS THE RUMEN WALL OF SHEEP
Authors: Warner A. C. I. , Stacy B. D. 
Published: December 2014

Saliva was entirely diverted from the rumen of sheep via an oesophageal fistula and usually replaced by infusion of a synthetic saliva of known composition. Water movements in the rumen were measured by the use of soluble markers, and sodium and potassium movements were calculated. Water and various solutions were added to the rumen to vary its osmolality over the range 180–550 m‐osmole/kg.When saliva was not replaced, recovery of the normal rumen osmolality following water loading was very slow indeed. When saliva was replaced by a synthetic solution the rate of water movement across the rumen wall (y, [l./hr]) was a linear function of the osmotic pressure (x, [m‐osmole/kg]), such that y = 0·404–0·001206x (r = ‐0·90). This suggests that the filtration permeability of the rumen wall was similar to that of frogskin or toad bladder.Potassium absorption across the rumen wall was also slow but positively related to the potassium concentration. Sodium absorption appeared to depend on the potassium concentration and the osmotic pressure as well as on the sodium concentration. While moderate levels of potassium increased the rate of sodium absorption, grossly high levels, sufficient to produce a substantial entry of water across the rumen wall, decreased it, sometimes markedly. The rate of potasium and perhaps sodium absorption seemed to depend on the immediate state of nutrition of the animal.