bluuebunny/crossref_metadata_2025 huggingface dataset:
Transfusion‐associated circulatory overload in Ireland: a review of cases reported to the National Haemovigilance Office 2000 to 2010
Authors: Piccin Andrea , Cronin Marina , Brady Róisín , Sweeney Jackie , Marcheselli Luigi , Lawlor Emer
Published: December 2014

Background

Transfusion‐associated circulatory overload (TACO) is an increasingly reported condition but symptoms and signs are still unrecognized. We present a review of the incidence and clinical features of TACO reported to the National Haemovigilance Office at the Irish Blood Transfusion Service.

Study design and methods

Between 2000 and 2010, a total of 1071 cases of serious transfusion‐related reactions were reported, of which 221 (21%) cases were TACO.

Results

A total of 2,000,684 blood components were issued, with a TACO incidence of one in 9177. The TACO incidence per red blood cells, plasma, and platelet components issued was one in 8000, one in 16,000, and one in 57,884, respectively. The majority of cases (68%, n = 151) were elderly patients, while no sex difference was seen. Twenty‐eight (13%) patients experienced severe morbidity; 31 (14%) deaths were reported, of which five (2%) were considered due to TACO and the other deaths considered due to and underlying conditions, which in most cases were cardiovascular (76%). An increased risk of mortality was found in patients on diuretics either before transfusion as part of their routine therapy or given as pretransfusion medication (odds ratio, 2.49; 95% confidence interval, 1.06‐6.01). In 19 (21%) cases, TACO reaction was due to human error.

Conclusions

The strong association between TACO and human errors supports the role of hemovigilance and of adequate transfusion medicine teaching for preventing morbidity and mortality associated with TACO.
Internal medicine resident knowledge of transfusion medicine: results from the BEST‐TEST international education needs assessment
Authors: Haspel Richard L. , Lin Yulia , Mallick Ranjeeta , Tinmouth Alan , Cid Joan , Eichler Hermann , Lozano Miguel , van de Watering Leo , Fisher Patrick B. , Ali Asma , Parks Eric ,   BEST‐TEST Investigators
Published: December 2014

Background

Blood transfusion is the most common hospital procedure performed in the United States. While inadequate physician transfusion medicine knowledge may lead to inappropriate practice, such an educational deficit has not been investigated on an international scale using a validated assessment tool. Identifying specific deficiencies is critical for developing curricula to improve patient care.

Study Design and Methods

Rasch analysis, a method used in high‐stakes testing, was used to validate an assessment tool consisting of a 23‐question survey and a 20‐question examination. The assessment tool was administered to internal medicine residents to determine prior training, attitudes, perceived ability, and actual knowledge related to transfusion medicine.

Results

A total of 474 residents at 23 programs in nine countries completed the examination. The overall mean score of correct responses was 45.7% (site range, 32%‐56%). The mean score for Postgraduate Year (PGY)1 (43.9%) was significantly lower than for PGY3 (47.1%) and PGY4 (50.6%) residents. Although 89% of residents had participated in obtaining informed consent from a patient for transfusion, residents scored poorly (<25% correct) on questions related to transfusion reactions. The majority of residents (65%) would find additional transfusion medicine training “very” or “extremely” helpful.

Conclusion

Internationally, internal medicine residents have poor transfusion medicine knowledge and would welcome additional training. The especially limited knowledge of transfusion reactions suggests an initial area for focused training. This study not only represents the largest international assessment of transfusion medicine knowledge, but also serves as a model for rigorous, collaborative research in medical education.
Household Savings and Housing Prices in China
Authors: Wan Junmin
Published: December 2014

Using Phillips et al. (2012, ‘Testing for Multiple Bubbles’, Yale University) bubble test and the ratio of monthly housing price to rent in China, we cannot find that there were bubbles in the housing market for all provinces including urban and rural sectors during January 2000 to August 2011, but we found that there were housing bubbles for the 36 major cities during December 2004 to July 2011. By the panel provincial data during 1995–2010 in China, we found that the bubbly housing price, especially in the urban sector, significantly raises the household saving rate in cities as well as nationwide after controlling for the life cycle and the other related factors. Based on the micro household data for six major cities in China in 2005, we also find that the increase in housing price and housing loans has significantly positive impacts on household saving, even after controlling for other possible factors. The empirical results here are consistent with the predictions of the speculative saving hypothesis.
The use of rituximab to prevent severe delayed haemolytic transfusion reaction in immunized patients with sickle cell disease
Authors: Noizat‐Pirenne F. , Habibi A. , Mekontso‐Dessap A. , Razazi K. , Chadebech P. , Mahevas M. , Vingert B. , Bierling P. , Galactéros F. , Bartolucci P. , Michel M.
Published: December 2014

Background

Delayed haemolytic transfusion reaction (DHTR) is mainly caused by an immune response to transfused red blood cells (RBCs). Immunized patients have a high risk of producing antibodies in response to further transfusion. Controlling the immune response to RBCs is therefore a major goal in sickle cell disease (SCD).

Study design

We report an observational study of eight alloimmunized SCD patients with history of severe DHTR who were treated with rituximab before a new transfusion to prevent further immunization and DHTR.

Results

Five patients showed a good clinical outcome following transfusion preceded by preemptive treatment with rituximab. The remaining patients presented mild DHTR. In all patients, the results of post‐transfusion screening tests were identical to those of pretransfusion tests; no newly formed antibodies were detected.

Conclusion

These cases suggest that rituximab prevents at least occurrence of newly formed antibodies in high responders and minimizes the risk of severe DHTR. This study confirms that DHTR is complex in SCD and does not rely only on the classical antigens/antibodies conflict. Considering potentially serious adverse effect of rituximab, this treatment should be considered cautiously, and only when transfusion is absolutely necessary in patients with history of severe DHTR linked to immunization.
HÆMOGLOBIN CONCENTRATION, HÆMATOCRIT VALUE, AND SEDIMENTATION RATE OF HORSE BLOOD
Authors: Fegler G.
Published: December 2014

1. Volume p.c. of r.b.c., hæmoglobin concentration, relative viscosity of the plasma and blood, and the sedimentation rate of the r.b.c. have been estimated on 7 healthy horses.

2. Increase in the volume p.c. of r.b.c. was found in the excited or working horse. The concentration of r.b.c. in blood from the jugular vein in horses at rest is rather low in comparison with other animals.

3. Increase in the Hb. g. p.c./r.b.c. V. p.c. ratio was found in cases with the higher volume p.c. of r.b.c. with a significant correlation coefficient.

4. Apparent relative viscosity of horse blood at higher volume p.c. of r.b.c. is higher than that of ox or sheep blood at corresponding volume p.c. of r.b.c., the higher viscosity of plasma being one of the causes.

5. Maximum sedimentation rate of r.b.c. in heparinised whole blood of the horse varied from 0·6 mm. to 5·9 mm. per min., depending on the r.b.c. concentration. The sedimentation rate of the horse r.b.c. is also high in sheep or ox plasma, whereas the r.b.c. of these species sediment as slowly in horse plasma as in their own.

6. The physiological significance of the high sedimentation rate of the horse r.b.c. was discussed.
The action of extracellular cations on the release of the sympathetic transmitter from peripheral nerves
Authors: Boullin David J.
Published: December 2014

1. The noradrenaline stores in the sympathetic nerve endings of the cat colon were labelled in vivo with (±)‐[7‐3H]noradrenaline (500 μc, 11·3 μg) injected 3 hr before killing.

2. The colon was removed and immersed in an organ bath containing Krebs solution. The vascular bed was perfused from the inferior mesenteric artery to the colic vein.

3. The effects of Ca2+, Ba2+ and Mg2+ on the output of [3H]noradrenaline and [3H]metabolites in the venous effluent were measured before and after electrical stimulation of the post‐ganglionic inferior mesenteric nerves at 10 impulses/sec.

4. Nerve stimulation increased the efflux of [3H]noradrenaline when the perfusion fluid contained Ca2+. Variations in Ca2+ concentration (1·5‐10 m
M) did not affect this response.

5. Removal of Ca2+ from the fluid passing through the vascular bed (and therefore from the region of the sympathetic nerve terminals), abolished the output of [3H]noradrenaline in response to nerve stimulation. There was no change when phenoxybenzamine was added to prevent the binding of transmitter on to post‐synaptic receptors on the effector organ.

6. The output of transmitter was not changed when Ca2+ was present in the blood vessels of the colon even though it was removed from the solution in contact with the remainder of the tissue.

7. Nerve stimulation released [3H]noradrenaline when Ba2+ was used as a substitute for Ca2+; Mg2+ was not an effective substitute for Ca2+ as then nerve stimulation did not increase the output of radioactive noradrenaline or metabolites.

8. Ba2+ also increased the resting output of [3H]noradrenaline in the absence of nerve stimulation. Addition of Ca2+ or Mg2+ did not change this spontaneous release but it was augmented by removal of Ca2+.

9. It is concluded that Ca2+ is essential for release of the sympathetic transmitter by nerve stimulation but not for the spontaneous output that occurs in the absence of nervous activity. The site of action of Ca2+ is considered to be the terminals of adrenergic fibres.
Chemosensitivity of cardiac muscle
Authors: Williams E. M. Vaughan , Whyte J. M.
Published: December 2014

1. Measurements of contractions, conduction velocity and intracellular potential were made on isolated rabbit atria under four sets of conditions: high bicarbonate/high CO2 (HH), low bicarbonate/low CO2 (LL), high bicarbonate/low CO2 (HL) and low bicarbonate/high CO2 (LH). The ratio high/low was the same for the bicarbonate and CO2 concentrations, so that HH had the same pH as LL.

2. Acid solutions caused a fall of a few mV in the resting potential, but not in the overshoot. They reduced conduction velocity and rate of rise of the action potential. They depressed contractions, but prolonged the tail of the action potential.

3. Alkaline solutions caused the converse changes, but, with the exception of the effect on the duration of the action potential, the relation with pH was markedly alinear, in that a rise in pH had much less effect than an equivalent fall.

4. Statistical tests were devised to decide whether the observed changes were associated primarily with pH, PCO2 or bicarbonate. By far the strongest association was with external pH. Changes in PCO2, per se, had no significant effect.
Properties of the inhibitory potential of smooth muscle as observed in the response to field stimulation of the guinea‐pig taenia coli
Authors: Bülbring Edith , Tomita T.
Published: December 2014

1. The inhibitory potential evoked by field stimulation of the guineapig taenia coli was studied in hypertonic solution in which the spontaneous electrical and mechanical activity was slowed or abolished.

2. There was no direct correlation between the inhibitory potential and the muscle membrane polarization in response to the stimulating current. The chronaxie for the inhibitory potential was less than 1 msec and that for the muscle spike 20‐30 msec.

3. The inhibitory potential decreased in size along the tissue when one end of the tissue was stimulated, but its spatial decay was slower than that of the electrotonic potential in the muscle bundle.

4. Tetrodotoxin (5 × 10−7 g/ml.) abolished the inhibitory potential without affecting the electrical properties of the muscle membrane. It was concluded that the inhibitory potential was the result of stimulation of intrinsic inhibitory nerves.

5. The following properties of the intrinsic nerve fibres were deduced from the experimental results: The length of the nerve fibres is probably only a few mm and the space constant of the order of 0·1 mm. No repetitive firing is produced by a long current pulse. The absolute refractory period is 3‐4 msec.
The effect of cations on the electrical properties of the smooth muscle cells of the guinea‐pig vas deferens
Authors: Bennett M. R.
Published: December 2014

1. A study has been made of the effects of Na+ and Ca2+ on the responses generated by intracellular current pulses in smooth muscle cells of the guinea‐pig vas deferens and upon the propagated action potential.

2. Reduction of the extracellular Na+ activity (aNa) to less than 30 m
M did not alter the characteristics of the spike‐like response to intracellular current pulses (the active response) or of the propagated action potential.

3. Reduction of the extracellular Ca2+ activity (aCa) to 0·1 m
M decreased the resting input resistance of the cells but increased the input resistance during the crest of the active response. Reduction of Ca2+ decreased the overshoot of the action potential by 22 mV per tenfold change in Ca2+ and the resting potential by 25 mV per tenfold change.

4. Reduction of the extracellular Ca2+, keeping the product aCa/a2Na constant, did not change the resting potential, but decreased the action potential overshoot by 20 mV per tenfold change.

5. It is suggested that part of the current responsible for the rising phase of the action potential is carried by Ca2+.
Intracellular enzymes in local lymph as a measure of cellular injury
Authors: Lewis G. P.
Published: December 2014

1. Lymph was collected directly from the hind limb of cats anaesthetized with pentobarbitone before and for several hours after the limb was injured.

2. After the limb was subjected to very mild injury such as hot water at 50° C or ischaemia for 1 hr there was no increase in protein or enzyme concentrations in the lymph, although after the ischaemia there was an increase in lymph flow.

3. After burning the limb at 60° C there was a significant increase in the concentrations of the cytoplasmic enzymes glutamic‐oxalacetic transaminase and lactic dehydrogenase, as a result of an increased permeability of the cell membrane.

4. When the limb was burned at 80° C there was a marked increase not only in the cytoplasmic enzymes but also in the mitochondrial enzyme glutamic pyruvic transaminase. Thus with the stronger burn the permeability of the intracellular mitochondrial membrane was also increased.

5. Not until the most severe injury of all, i.e. freezing the limb solid, was there an increase in the concentration of lysosomal enzymes in the lymph.

6. It is concluded that estimation of intracellular enzymes in the lymph draining an injured tissue affords a method of assessing the extent of cellular injury.
Post‐synaptic effects of cortical stimulation on forelimb motoneurones in the baboon
Authors: Kernell D. , Chien-Ping Wu
Published: December 2014

1. The arm area of the baboon's precentral motor cortex was stimulated by brief surface‐anodal pulses, and the post‐synaptic potentials elicited in contralateral forelimb motoneurones were studied by intracellular recording.

2. Strong cortical stimuli elicited a rapid series of excitatory and, in some cells, inhibitory post‐synaptic potentials (EPSPs and IPSPs respectively). Comparisons with the simultaneously recorded response of the pyramidal tract indicated that these post‐synaptic potentials were due to a repetitive discharge of fast pyramidal fibres. Thus, the later synaptic events were mostly due to a repetition of the early monosynaptic EPSP and early IPSP respectively.

3. Inhibition was seen more often in cells whose monosynaptic EPSP had a small maximal size than in those whose monosynaptic EPSP was larger. The net depolarization produced by a strong cortical stimulus was related to the maximal size of the early monosynaptic EPSP.

4. In the Discussion, an interpretation is suggested for previous findings concerning the spinal distribution of late synaptic effects elicited by cortical stimulation.
Responses in the dorsal accessory olive of the cat to stimulation of hind limb afferents
Authors: Armstrong D. M. , Eccles J. C. , Harvey R. J. , Matthews P. B. C.
Published: December 2014

1. Field potentials and single unit discharges were recorded in the dorsal accessory olive of the cat following stimulation of nerves of the contralateral hind limb.

2. The largest field potentials were evoked when nerves were stimulated with brief trains at 200‐300/sec. Responses were sometimes evoked from quadriceps nerve by volleys restricted to low threshold group I afferents, but responses were not usually evoked from other muscle nerves unless both group I and II afferents were excited.

3. The spatial distributions of the field potentials evoked from different nerves were very similar and individual units were made to discharge by stimulation of each of a wide range of nerves including muscle, skin and joint nerves. Single units were also made to discharge by stimulation of both the ipsilateral and the contralateral quadriceps nerve.

4. The latency of the field potentials evoked by stimulation of quadriceps nerve ranged from 14 to 23 msec in different preparations. The latency of responses evoked from various branches of the sciatic nerve was consistently longer and was usually between 20 and 30 msec.

5. The activity was conveyed by a tract which, at the upper lumbar level of the spinal cord, lay in the ventral quadrant ipsilateral to the olive. In the upper cervical region the tract lay close to the ventral surface of the cord. Values between 24 and 30 m/sec were found for the conduction velocity of the tract.

6. An excitatory response in the dorsal accessory olive was followed by a period of about 100 msec during which the amplitude of a second response was reduced.
The distribution of the T‐system along the sarcomeres of frog and toad sartorius muscles
Authors: Peachey L. D. , Schild Renée F.
Published: December 2014

1. Frog and toad sartorius muscles were soaked in ferritin suspensions and then fixed and prepared for electron microscopy. Ferritin particles were counted in micrographs of regions where fibril striations were in good register, and the number of particles plotted according to position along the sarcomeres.

2. The distribution of ferritin particles in both frog and toad muscle sarcomeres could be accounted for by a single peak centred at the Z‐line, with a total width of about 0·4 μ.

3. The peak in toad fibres was slightly broader than that in frog fibres, and this was due to more frequent branching of the T‐system in the toad. In both frog and toad sartorius muscles branching increases the total quantity of T‐system by around 30%.

4. No peak was found in the ferritin distribution which could account for the peak of albumin distribution observed near the A—I boundary of toad sartorius muscles by Hill (1964).
The evolution of fatigue associated with isometric contraction in toad sartorius
Authors: Aljure Emilio F. , Borrero Luis M.
Published: December 2014

1. The development of fatigue in isolated toad sartorius undergoing short, periodic, isometric tetani of controlled duration, was studied. Stimulation was direct and curare was used.

2. In the great majority of cases extratension decreased very regularly towards a steady value, following a simple exponential equation.

3. The final steady tension (expressed as percentage of the maximum) and the constant of exponential decay varied as simple functions of the mean frequency of stimulation and their product was a constant.
Renal contribution to thoracic duct lymph in dogs
Authors: O'Morchoe C. C. C. , O'Morchoe P. Jean
Published: December 2014

1. The renal contribution to thoracic duct lymph was measured in seventeen anaesthetized fasting dogs by measurement of thoracic duct flow before and after renal arterial occlusion.

2. In eight experiments it was shown that thoracic duct flow and glomerular filtration rate were not significantly affected by the operation to expose the renal artery.

3. In three experiments occlusion of the renal vein, after release of arterial occlusion, resulted in a sudden increase in thoracic duct flow.

4. In animals infused with isotonic saline or dextrose (approximately 1 ml./min) the average values obtained for control thoracic duct flow, left renal flow and right renal flow were approximately 2·0, 0·7 and 0·3 ml./hr/kg body wt.: in non‐infused animals these values were 1·4, 0·4 and 0·35 ml./hr/kg body wt. respectively.

5. Possible reasons for the apparently smaller lymph flow from the right than the left kidney, and the relationship between the renal contribution to thoracic duct flow and actual renal lymph flow are discussed.

6. Close correlation was found between control thoracic duct flow and body weight and between renal lymph flow and control thoracic duct flow.
The slowing of gastric emptying by monosaccharides and disaccharides in test meals
Authors: Elias E. , Gibson G. J. , Greenwood Linda F. , Hunt J. N. , Tripp J. H.
Published: December 2014

1. Test meals containing various concentrations of glucose, maltose, sucrose, fructose, lactose, galactose and mixtures of these solutes were given to six healthy subjects. All meals contained 40 m
M sodium citrate.

2. The slowing of gastric emptying produced by the disaccharides in test meals was generally consistent with the stimulation of duodenal osmoreceptors occuring after the hydrolysis of the disaccharides.

3. Glucose was slightly more effective, per osmole, in slowing gastric emptying than was galactose.

4. By comparison with glucose or galactose, fructose was much less effective in slowing gastric emptying. In three subjects out of six there was a threshold for its effect.

5. The results may be indicative of the relative activities of disaccharidases in the brush border of the small intestine. They are consistent with there being an osmoreceptor deep to these enzymes which slows gastric emptying.
Effects of tetrodotoxin on the slowly adapting stretch receptor neurone of lobster
Authors: Albuquerque E. X. , Grampp W.
Published: December 2014

1. A study has been made of the effects of tetrodotoxin on the impulse activity, resting membrane potential, input resistance, and the generator potential and its after‐hyperpolarization of the slowly adapting stretch receptor neurone of the lobster.

2. Tetrodotoxin was able to abolish completely within about 2 min the impulse activity in most cells, when given in a dose of 2 × 10−8 g/ml., but in all cells, when administered in a dose of 4 × 10−8 g/ml. After blockage by the toxin in concentrations as high as 4 × 10−6 g/ml. for periods of up to 30 min the action potential was restored by washing the preparation in physiological solution for 1 hr.

3. In a concentration of 4 × 10−8 g/ml. tetrodotoxin produced within 1–2 min an average increase of 4·8 mV of the resting membrane potential and a simultaneous 47% reduction of the resting input resistance. These effects were reversed by washing the preparation in physiological solution for 1 hr.

4. Tetrodotoxin administered in doses as high as 4 × 10−6 g/ml. for periods of up to 30 min had no effect on the amplitude of the steady phase of the generator potential.

5. In a concentration of 4 × 10−8 g/ml. tetrodotoxin produced within 5 min a 65% reduction of the amplitude of the hyperpolarization following the generator potential. This effect was reversed by washing the preparation in physiological solution for 1 hr.

6. The simultaneous increase in resting membrane potential and decrease in membrane resistance is suggested to be due to an elevated potassium permeability besides a reduced sodium conductance. The constancy in height of the generator potential in the presence of a decreased membrane resistance makes necessary the assumption of an augmented generator current. The decrease in amplitude of the hyperpolarization following the generator potential may be the result of an increase in potassium conductance and/or a reduction in acceleration of an electrogenic pump in consequence of a diminished sodium influx during the generator potential.
Heat work and phosphorylcreatine break‐down in muscle
Authors: Wilkie D. R.
Published: December 2014

1. A new instrument, the integrating thermopile, is described for measuring the total quantity of heat produced during muscular contraction.

2. This instrument has been used to investigate the relation between change of enthalpy (‐ (heat produced + work produced)) and break‐down of phosphorylcreatine (ΔPC) in iodoacetate‐poisoned frog sartorii at 0° C. In a variety of different types of contraction—series of isometric twitches, isometric tetani, contractions with positive and with negative work—the relation between enthalpy change and ΔPC was always the same, and corresponded to an in vivo molar enthalpy change (ΔH) of ‐11·0 ± 0·23 (
S.E.; n = 52) kcal/mole.

3. This value of ΔH is used to estimate the in vivo ΔH for ATP splitting and also the number of rephosphorylations to be expected per hexose unit oxidized by normal unpoisoned muscle.
The kinetics and rectifier properties of the slow potassium current in cardiac Purkinje fibres
Authors: Noble D. , Tsien R. W.
Published: December 2014

1. The reversal potential of the slow outward current in Purkinje fibres varies with [K]o in accordance with the expected potassium equilibrium potential. It is concluded that virtually all of this current is carried by potassium ions.

2. The magnitude of the current is determined by two separable factors. The first factor is directly proportional to a variable obeying first‐order voltage‐dependent kinetics of the Hodgkin—Huxley type but with extremely long time constants. The time constants of this variable are extremely sensitive to temperature and the Q10 over the range 26‐38° C is 6.

3. The second factor shows inward‐going rectification with a marked negative slope in the current—voltage relation beyond about 25 mV positive to the K equilibrium potential. The current—voltage relations measured at different values of [K]o cross each other on the outward current side of the equilibrium potential.

4. The changes in slow potassium current during pace‐maker activity have been calculated. It is shown that the mechanism of the pace‐maker potential differs in several important respects from that described by Noble's (1962) model. The negative slope in the current—voltage relation appears to be an important factor in generating the last phase of pace‐maker depolarization.

5. The role of the slow potassium current during the action potential and the consequences of the high temperature dependence of the kinetics are discussed.
Amiloride: a potent inhibitor of sodium transport across the toad bladder
Authors: Bentley P. J.
Published: December 2014

1 Amiloride inhibits Na transport and short‐circuit current (SCC) across the toad bladder. It is 1000 times more active at the mucosal than serosal surface. The lowest effective concentration was 10−7
M.

2. The inhibition was non‐competitive with the sodium on the mucosal side of the bladder.

3. Vasopressin, cyclic adenosine monophosphate (AMP) and aldosterone increased Na transport and SCC across the bladder and these effects were inhibited by amiloride.

4. The antagonism of amiloride for vasopressin was non‐competitive.

5. Amphotericin B also increases Na transport across the bladder but its action was not changed by amiloride.

6. Amiloride was without effects on SCC and diffusion potentials in bladders metabolically inhibited with CN− and iodoacetic acid (IAA).

7. Neither plasma albumin, Ca2+ nor adenosine triphosphate (ATP) altered the effects of amiloride.

8. The only structural analogue of amiloride found to reduce SCC similarly was guanidine which was 1000 times less active. Pyrazine and a substituted pyrazine analogue were without effect. Neither guanidine nor the substituted pyrazine compound were competitive with amiloride.

9. Amiloride had no effect on the osmotic permeability of the toad bladder either in the presence or absence of vasopressin.

10. Na transport across the toad colon was also reduced by 10−5
M amiloride at the mucosal surface.

11. The possible mechanism of action of amiloride is discussed.
A dual effect of calcium ions on neuromuscular facilitation
Authors: Rahamimoff R.
Published: December 2014

1. The changes in neuromuscular facilitation produced by varying extracellular calcium and magnesium concentrations have been studied at the frog neuromuscular junction using intracellular recording and automatic averaging of responses.

2. When [Ca] was elevated three effects were observed: a large increase in transmitter release by the first impulse; a decrease in facilitation at short intervals between impulses; and a prolongation of the time course of the facilitated release. If the release by the first impulse is kept at constant level, by raising both [Ca] and [Mg], facilitation becomes greater at all impulse intervals.

3. The results have been discussed in terms of the hypothesis that the action of calcium is responsible for neuromuscular facilitation.
Renal sodium reabsorption after acute renal denervation in the rabbit
Authors: Blake William D. , Jurf Amin N.
Published: December 2014

1. Separate effects on the functions of left and right kidneys were examined after left‐sided renal handling and acute denervation. Studies were done on pentobarbital‐anaesthetized rabbits using clearance techniques to evaluate renal haemodynamics and water and electrolyte excretion.

2. When compared with its counterpart, the handled kidney exhibited some decrease in function for at least 20 min. Recovery of most functions occurred in 40‐60 min.

3. The effects of denervation on renal functions were observed when the effects of handling had subsided. Renal plasma flow (
R.P.F.) and glomerular filtration rate (
G.F.R.) were not significantly changed, whereas the decrease in Na, K and water excretion, which was usually observed for no ascertained reason in the innervated kidney, was prevented.

4. The magnitude of the denervation natriuresis was greater in these rabbits than in dogs studied previously; other functions studied were comparable in the two species.

5. The results from thirty‐five experiments are interpreted to indicate that denervation decreases Na reabsorption independently of
G.F.R., perhaps by a direct effect on tubular transport, but more probably by a redistribution of filtration to nephrons of lesser reabsorptive capacity.
On the increase in rate of heat production caused by stretch in frog's skeletal muscle
Authors: Clinch N. F.
Published: December 2014

1. The increase in rate of heat production caused by stretch in the unstimulated frog's sartorius (stretch response) has been measured using a conventional thermopile technique.

2. The rate of heat production was found constant between l0 (the distance in vivo between the tendons when the legs were in a straight line) and 1·2 l0, and rose rapidly above this length to reach 3‐5 times the basal rate at 1·3 l0. Stretching to greater lengths appeared to damage the muscles.

3. The stretch response is increased by several substances which increase the duration of the active state.

4. Unlike the rate of heat production at l0, the stretch response is increased by procaine; while the presence of CO2 greatly reduces it.

5. Evidence is presented supporting the hypothesis that the stretch response is associated with the appearance of tension in the sarcolemma.
Factors influencing the sensitivity of the rat to vasopressin
Authors: Forsling Mary L. , Jones J. J. , Lee J.
Published: December 2014

1. Indirect evidence suggests that the concentration of arginine vasopressin in the plasma of normally hydrated man is about 1 μ‐u./ml., but this is usually considered to be below the limit of sensitivity of the standard assay preparation, the water‐loaded Wistar rat under ethanol anaesthesia.

2. It was found that there was a surprising variation in sensitivity to vasopressin between batches of Wistar rats, and that other varieties of rat (including those with diabetes insipidus) were no more sensitive.

3. Three modifications of the standard assay procedure produced an increase in sensitivity:

(a) using Wistar rats weighing 100‐150 g, rather than larger animals;

(b) commencing the assay shortly after surgery, i.e. as soon as the urine flow reached 25 μl./min;

(c) infusing vasopressin intravenously (0·5‐3 μ‐u./min). By using modification (a) with either (b) or (c) it was possible to detect as little as 0·5 μ‐u.

4. With these modifications antidiuretic activity equivalent to 0·5‐2·0 μ‐u./ml. of arginine vasopressin was measured in nine samples of plasma from a normally hydrated subject.

5. It is suggested that the frequent reports of enhanced sensitivity may have been due to the fortuitous use of a particularly sensitive batch of rats, or to a high endogenous secretion of vasopressin due to operative trauma.
Effects of amino acids, dipeptides and disaccharides on the electric potential across rat small intestine
Authors: Kohn P. G. , Smyth D. H. , Wright E. M.
Published: December 2014

1. The effects of a number of amino acids, peptides and disaccharides on the potential difference across the wall of the rat small intestine have been studied.

2. All the
L‐amino acids tested, except lysine and arginine, and the three
D‐amino acids tested stimulate the potential when present in the mucosal fluid.

3. The concentration dependence and time course of the potential differs between different amino acids.

4. The results suggest a close correlation between the active transport of an amino acid and the potential change which it evokes.

5. Glycyl‐glycine, glycyl‐
L‐alanine and tri‐glycine stimulate the potential and this appears to be due to the amino acids liberated by hydrolysis.

6. Maltose and sucrose, but not lactose, stimulate the potential, and the effect appears to depend on the extent of hydrolysis of the disaccharide.

7. The magnitude of the potential varies in different parts of the intestine. For the amino acids tested the maximum potential occurred in the distal ileum, while in the case of hexoses the maximum potential was found in the mid‐intestine.

8. The results are discussed in relation to the mechanisms of transfer of hexoses and amino acids.
The time course of changes in renal tissue composition during mannitol diuresis in the rat
Authors: Atherton J. C. , Hai M. A. , Thomas S.
Published: December 2014

1. The time course and extent of changes in the composition of renal tissue slices in osmotic diuresis were determined by sacrificing groups of rats before and during the intravenous infusion of mannitol (15 g/100 ml.) for up to 7½ hr.

2. Very rapid changes in tissue water and solute contents occurred within 15 min, preceding the times of maximal diuresis, with little subsequent change even up to 7½ hr.

3. The main changes were:

(a) an increase in water content in all slices, particularly the papilla; (b) a very profound decrease in papillary and medullary urea content in the first 15 min, with a small, but significant, further decrease, subsequently; (c) a small, but significant, rapid decrease in papillary sodium, and small non‐significant increases in the outer medulla and cortex. Subsequent changes in any segment were small and non‐significant; (d) apart from small changes in the first 15 min ammonium and potassium contents remained fairly constant.

4. The rates of change in papillary and urinary urea concentrations were similar, so that after 30 min, any differences between tip and urinary concentrations were small and non‐significant.

5. The findings are discussed in terms of factors influencing counter‐current mechanisms. It is concluded that altered medullary blood flow is mainly responsible for the rapid changes in medullary composition.

6. The relation between papillary and urinary urea concentrations is explicable in terms of passive handling, with equilibration across a freely permeable collecting duct membrane.
The time course of changes in renal tissue composition during water diuresis in the rat
Authors: Atherton J. C. , Hai M. A. , Thomas S.
Published: December 2014

1. The time course and extent of changes in the composition of renal tissue slices in water diuresis were determined by sacrificing groups of rats before and during the intravenous infusion of dextrose (2·5 g/100 ml.) in amounts sufficient to administer over 2 hr, and subsequently to maintain for up to 7½ hr, a positive fluid load of 4% body weight.

2. The corticomedullary osmolal gradient characteristic of the nondiuretic rats was progressively dissipated until, at 7½ hr, only papillary tip concentrations were higher than those of other segments.

3. The changes in individual constituents followed different time courses: (i) an increase in water content in all segments, particularly the papilla, was almost complete by 1 hr, preceding the maximal increases in urine flow; (ii) a marked decrease in papillary and medullary urea content in the first hour was followed by a slower, progressive decrease leading to an almost complete dissipation of the urea gradient by 7½ hr; (iii) small, non‐significant decreases in sodium content occurred in all segments in the first hr, followed by a further small, progressive decrease in papillary sodium content; (iv) changes in ammonium and potassium concentrations were mainly related to those in water content, since the contents of these solutes showed only small changes.

4. By 2 hr, differences in the rates of decline of osmolal and urea concentrations in urine and papilla led to urinary concentrations significantly lower than papillary values. The steep papilla‐urine urea concentration difference became smaller, but remained significant even at 7½ hr.

5. The findings are discussed in terms of changes in countercurrent mechanisms, particularly as influenced by anti‐diuretic hormone.

6. The development of papilla/urine urea concentration ratio greater than unity is also considered in terms of passive transport with changes in membrane permeability.
The energetics of tortoise muscle
Authors: Woledge R. C.
Published: December 2014

1. A study has been made of the mechanical behaviour and the heat production of tortoise skeletal muscle during tetanic contractions.

2. The relation between force (P) and velocity (v) is more curved than that of frog muscle. It can be fitted by Hill's equation (v/vmax = (1 ‐ P/P0)/(1 + P/a)) using a value of P0/a considerably less than for frog muscle.

3. The value of the shortening heat constant is less than in frog muscle. It is about a half of a. No evidence was found that the value depended on the load.

4. The maintenance heat rate is much less than in frog muscle and, as in frog muscle, is roughly equal to a.b (where b = vmax.a/P0). The maintenance heat rate does not diminish during a long tetanus as it does in frog muscle.

5. The ratio of work/(work + initial heat) is greater in tortoise muscle than in frog muscle. As in frog muscle, the recovery heat is about equal to (work + initial heat). It follows that tortoise muscle is more efficient than frog muscle at converting free energy into work.

6. Possible theoretical bases for connexions between the shape of the force—velocity curve of a muscle and its efficiency are discussed.
A study of the end‐plate potential in sodium‐deficient solution
Authors: Kordaš M.
Published: December 2014

1. The effect of anticholinesterases in lengthening the end‐plate potential is much more pronounced in a low‐sodium solution than in an ordinary Ringer‐curare solution.

2. To investigate this difference, intracellular recordings of end‐plate potentials and of end‐plate currents in voltage‐clamped muscle fibres were used.

3. It was found that the very large lengthening of the end‐plate potential in a low‐sodium solution was due to a combination of three factors: (i) lengthening of the underlying end‐plate current, (ii) an increased membrane resistance and (iii) marked inward‐going (anomalous) rectification of the muscle membrane.
Energy cost of tonic contraction in a lamellibranch catch muscle
Authors: Baguet F. , Gillis J. M.
Published: December 2014

1. The oxygen consumption of isolated anterior byssus retractor muscle (ABRM) of Mytilus edulis was measured during tonic contraction induced by acetylcholine (ACh).

2. The respiration was measured with an oxygen electrode during 95 min, divided into one period of 5 min and six successive periods of 15 min.

3. Tonic contraction induced a prolonged increase of the basal respiration that slowly diminished with a time course roughly similar to that of the tonic tension.

4. For each period of measurement, the excess respiration over the resting level could be analysed into a constant amount and an amount that depended on the maintained tonic tension. The analysis was performed by fitting regression equations of the type Y = Q+bP, where Y is the excess respiration in n‐moles O2/g.min, and P, the isometric tension (kg/cm2); term b of the equation expresses the amount of oxygen consumption directly proportional to the tonic tension.

5. During the first 20 min of contraction, terms b of the equations are not significant, and most of the excess respiration (terms Q) is independent of the tension. The oxygen consumed during this time is supposed to reflect the recovery metabolism for the energy cost of the development of the tension.

6. From the 20th to the 80th min of contraction, terms Q are reduced and terms b are significant and constant. The excess respiration during this period is equal to 16·9 (±0·5) n‐moles O2/g.min + P × 6·8 (±0·5) n‐moles O2/kg.cm.min (±
S.E. of the means, n = 24).

7. During a tonic contraction suppression of tension by a release reduced the oxygen consumption which increased again when tension was restored by stretching the muscle back to its original length. This confirmed the role of tension in determining the intensity of respiration during the catch.

8. The oxygen consumption related to this tension restored by stretching the muscle, varied from 8·0 to 12·3 n‐moles O2/kg.cm.min. These figures are of the same order of magnitude as the coefficient b obtained in the case of tonic contraction without modification of tension by length changes.

9. These results are taken as a demonstration that the maintenance of tonic tension is an ‘active’ phenomenon with a metabolic counterpart.
Interference with the metabolism of glucose by a non‐metabolizable hexose (3‐methylglucose)
Authors: Himsworth R. L.
Published: December 2014

1. It having previously been shown that the injection of the non‐metabolizable sugar, 3‐methylglucose, into normal rats provokes the release of adrenaline with consequent hyperglycaemia, the effect of 3‐methylglucose upon the metabolism of glucose was investigated. In rats, whose adrenal glands had been denervated by transplantation, 3‐methylglucose reduced the oxidation of glucose by 46%. A reduction of this magnitude cannot be accounted for unless the oxidation of glucose by the brain is depressed.

2. The lowering of the blood glucose concentration of adrenalectomized rats by insulin was prevented by the prior administration of 3‐methylglucose.

3. 3‐Methylglucose retarded the movement of a glucose load from the blood into the tissues.

4. The results of these experiments are consistent with competition between glucose and 3‐methylglucose for the glucose transfer system at cell surfaces.

5. The similarity between the effects upon cerebral metabolism of hypoglycaemia and the interference by a non‐metabolizable sugar with glucose transport into the brain, is discussed.
Effects of hyperventilation on the circulatory response of the rabbit to arterial hypoxia
Authors: Crocker E. F. , Johnson R. O. , Korner P. I. , Uther J. B. , White S. W.
Published: December 2014

1. The circulatory effects of artificial hyperventilation with air and low oxygen mixtures were studied in rabbits anaesthetized with chloralose‐urethane and given decamethonium iodide. The role of vagal afferents in the response to hypoxia was also assessed in spontaneously breathing unanaesthetized and anaesthetized animals.

2. In the anaesthetized rabbit artificial hyperventilation inhibited all the changes in autonomic activity to the heart and peripheral circulation resulting from stimulation of the arterial chemoreceptors, and also reduced vagal efferent tone. In animals with section of the carotid sinus and aortic nerves the changes in autonomic activity observed during hypoxia and hyperventilation were much smaller than in normal animals and affected only cardiac autonomic activity.

3. The effects of hyperventilation during hypoxia were mediated chiefly through vagal afferents rather than through the effects of hypocapnia. In the absence of changes in autonomic activity (e.g. during artificial hyperventilation with air) the circulatory effects were small and less clearly related to afferent vagal activity.

4. In the spontaneously breathing anaesthetized and unanaesthetized rabbit vagal afferent activity resulting from the respiratory response to hypoxia inhibits sympatho‐adrenal activity in the same way as during hypoxia with artificial hyperventilation.

5. The importance of the vagal afferent input in the rabbit is discussed in relation to the qualitative differences in circulatory response with increasing severity of hypoxia, and in relation to the effects of anaesthesia.
Secretion of kallikrein and its role in vasodilatation in the submaxillary gland
Authors: Beilenson Susanne , Schachter M. , Smaje L. H.
Published: December 2014

1. The effects of parasympathetic (chorda) and sympathetic nerve stimulation on the concentration and output of kallikrein secreted in saliva from the cat's submaxillary gland were compared. Sympathetic stimulation always produced a much higher concentration (up to 500 times) and output (up to 390 times) of kallikrein than parasympathetic stimulation. In the dog, in which sympathetic nerve stimulation produces little or no secretion from the submaxillary gland, there was also a marked increase in the secretion of kallikrein when sympathetic was superimposed on parasympathetic secretion. This effect did not occur, however, in the rabbit's submaxillary gland.

2. It was possible to deplete the cat's submaxillary gland of kallikrein, either by ligation of the duct for several days or by duct ligation and sympathetic nerve stimulation, so that it was undetectable either in the gland or in saliva after stimulation of the chorda. Such glands, nevertheless, responded to chorda stimulation with a normal atropine‐resistant vasodilatation.

3. There is a close parallelism between the rate of secretion of salvia and vasodilatation over a range of frequencies of chorda stimulation, but the output (and concentration) of kallikrein in saliva is distinctly different for the same frequencies of nerve stimulation.

4. Our results are consistent with the view that vasodilator nerves exist in the parasympathetic nerves to the submaxillary gland. We suggest that they are cholinergic in nature despite the fact that chorda vasodilatation is resistant to atropine. It is further suggested that neither the kallikrein—kinin system nor adrenergic vasodilator nerve fibres play a significant role in chorda vasodilatation.