The secretion of pancreatic juice in response to stimulation of the vagus nerves in the pig. 1. The secretory response to stimulation of the vagus nerves has been examined in the pig and compared with that in the dog under similar experimental conditions.2. In the pig, stimulation of the vagus nerves caused a profuse flow of pancreatic juice with a high content of bicarbonate, in addition to a secretion of digestive enzymes; atropine suppressed the secretion of enzymes but failed to diminish the flow of bicarbonate-rich juice.3. Intra-arterial injections of acetylcholine closely imitated the effects of stimulation of the nerves, with the difference that both the flow of juice and the secretion of enzymes were abolished together by atropine.4. Stimulation of the nerves and injections of acetylcholine were effective after resection of the stomach and intestine: these stimuli can therefore act directly on the pancreas, independently of the release of gastro-intestinal hormones.5. In the dog, the pancreas differed from that of the pig in that stimulation of the vagus nerves and injections of acetylcholine acted predominantly on the secretion of enzymes and caused only a sparse flow of juice. Atropine annulled all these effects together.6. The results show that the vagus nerves can exert a much wider control of the secretion of pancreatic juice in the pig than in the dog. Possible mechanisms for this action are discussed.


ATP utilization by fast and slow muscles during the development and maintenance of isometric tension.


The secretory and vascular response to nervous and hormonal stimulation in the pancreas of the pig. 1. The atropine-resistant action of the vagus nerves on the flow of pancreatic juice in the pig has been examined and related to certain properties of the pancreas in this species.2. The pancreas was more sensitive to secretin in the pig than in the dog, although similar maximal rates of secretion were observed in both species.3. The potentiation by secretin of the effects of parasympathetic stimulation on the flow of juice was conspicuous in the pig because of the heightened sensitivity to secretin and the resistance to atropine of this action of the secretory nerves.4. Stimulation of the vagus nerves increased the output of amylase in pancreatic juice more readily than injections of pancreozymin in the pig. In the dog pancreozymin was more effective than stimulation and could alone raise the amylase output to values comparable with those attained by stimulation in the pig. In both species atropine reduced the response to pancreozymin by only 20-25%, compared with 70-95% for vagal stimulation.5. Stimulation of the vagus nerves caused an intense, well maintained vasodilatation in the pancreas, which appeared after a shorter latent period than the secretion and was not diminished by atropine. Pancreozymin caused a smaller, and secretin only a slight, increase in pancreatic blood flow, which was also resistant to atropine, but appeared at the same time as the enhanced flow of juice. Injections of acetylcholine caused a vasodilatation which preceded the secretion but was abolished by atropine. The possibility that the pancreas receives an atropine-resistant parasympathetic vasodilator nerve supply is discussed.6. The results provide no evidence that a substance with specific secretin-like properties might be released within the pancreas to act as a secondary transmitter for the effect of stimulation of the vagus nerves on the flow of pancreatic juice.7. The experiments indicate that differences in the parasympathetic innervation of the exocrine cells of the pancreas between the pig and dog may underlie the observed differences in the secretory responses of the gland in these species.


Inorganic phosphate--a new candidate for mediator of functional vasodilatation in skeletal muscle.


The response of alpha motoneurones to movement of their muscles.


Characteristics of secondary endings in muscle spindles in caudal segmental muscles of the rat.


Increased uptake of calcium by human lymphocytes treated with phytohaemagglutinin.


The effects of prolonged treatment with ouabain on Na, K and Ca levels in cultured cells.


Reflex inhibition of monosynaptic reflexes by stimulation of type J pulmonary endings. 1. Monosynaptic reflexes, evoked from flexor and extensor hind limb muscle nerves in cats anaesthetized with pentobarbitone sodium, were depressed for several seconds after right intra-atrial injection of phenyl diguanide. Injection of the drug close to the aortic valves did not produce the same effect on the reflex. There was no obvious depression of polysynaptic reflexes on intra-atrial injection of phenyl diguanide.2. This depression of the monosynaptic reflex was present even after the administration of atropine, which lessened the hypotension due to phenyl diguanide. The blood gas tensions were also measured after the administration of phenyl diguanide, and were not altered to a degree where one would expect the depression to be secondary to a change in arterial gas tensions. The depression was also present in paralysed and artificially ventilated cats.3. The afferent pathway causing this depression of the monosynaptic reflex runs in the vagus nerve, as shown by experiments done before and after vagotomy. Intercollicular decerebration also abolished this inhibition of the monosynaptic reflex.4. Prior intravenous injection of strychnine (0.1 mg/kg) abolished the effect of intra-atrial administration of phenyl diguanide.5. It was concluded that stimulation of type J pulmonary endings causes a reflex inhibition of monosynaptic reflexes lasting for several seconds via regions of the brain cephalad to the intercollicular level.


Effect of intracellular calcium on the potassium permeability of human red cells.


Sodium pump reversal in the erythrocytes of various species.


Inhibition of active sodium transport in isolated frog skin by the diuretic, amiloride: site of action.


Release of acetylcholine by chick embryo heart before innervation. 1. In chick embryo hearts, 3-day-old and not yet innervated, repetitive direct stimulation causes a transitory inhibition of the spontaneous rhythm.2. The degree of post-stimulation inhibition depends on the frequency and duration of the artificial stimulation and on the concentration of K and Ca ions in the extracellular solution.3. After treatment with atropine (10(-5) g/ml.) post-stimulation inhibition is no longer observed. The spontaneous rhythm is accelerated by atropine. The findings therefore suggest that an ACh-like substance is released from the non-innervated embryonic heart during activity.4. By use of the dorsal muscle of the leech for biological assay the liberation of an ACh-like substance from the non-innervated embryonic heart was confirmed.


Renin secretion in the hypothermic dog.

Renin secretion in the hypothermic dog.


The location of the chemoreceptor controlling gastric acid secretion during hypoglycaemia. 1. The injection of 2-deoxy-D-glucose directly into the lateral hypothalamic area of rats, but not elsewhere, caused a prompt and sustained secretion of acid by the stomach at a rate comparable to that due to insulin hypoglycaemia.2. Acid secretion provoked by such injections, like that resulting from hypoglycaemia, could be stopped by raising the plasma glucose concentration by the intravenous infusion of glucose.3. Unilateral intrahypothalamic injection of 2-deoxy-D-glucose activated both vagi for, although cutting one vagus reduced the secretion, division of both was necessary to abolish it.4. Gastric acid secretion evoked by a systemic stimulus (insulin-induced hypoglycaemia or intravenous 3-O-methylglucose) could be prevented by inactivating the lateral hypothalamic area on each side with phenol or lignocaine.5. It is concluded that there exists in the lateral hypothalamic area a chemoreceptor, responsive to a lack of metabolizable glucose, which can initiate and sustain the vagally mediated secretion of acid by the stomach.


Hypothalamic control of adrenaline secretion in response to insufficient glucose. 1. The rise of plasma glucose consequent upon the release of adrenaline following the systemic administration of 3-O-methylglucose is prevented by previous infiltration with lignocaine of the lateral hypothalamic area on both sides.2. The similarity between this effect and that of the same procedure in preventing the hypersecretion of gastric acid in response to the same stimulus, together with the known fact that hypoglycaemia or the systemic administration of some glucose analogues produce both gastric and adrenal medullary hypersecretion, provides strong presumptive evidence that there exists in the lateral hypothalamic area a chemoreceptor which controls the release of adrenaline. The cells of this receptor like those of the chemoreceptor controlling gastric acid secretion, are activated by an insufficiency of metabolizable glucose.


The period of susceptibility to the physiological effects of unilateral eye closure in kittens. 1. Kittens were visually deprived by suturing the lids of the right eye for various periods of time at different ages. Recordings were subsequently made from the striate cortex, and responses from the two eyes compared. As previously reported, monocular eye closure during the first few months of life causes a sharp decline in the number of cells that can be influenced by the previously closed eye.2. Susceptibility to the effects of eye closure begins suddenly near the start of the fourth week, remains high until some time between the sixth and eighth weeks, and then declines, disappearing finally around the end of the third month. Monocular closure for over a year in an adult cat produces no detectable effects.3. During the period of high susceptibility in the fourth and fifth weeks eye closure for as little as 3-4 days leads to a sharp decline in the number of cells that can be driven from both eyes, as well as an over-all decline in the relative influence of the previously closed eye. A 6-day closure is enough to give a reduction in the number of cells that can be driven by the closed eye to a fraction of the normal. The physiological picture is similar to that following a 3-month monocular deprivation from birth, in which the proportion of cells the eye can influence drops from 85 to about 7%.4. Cells of the lateral geniculate receiving input from a deprived eye are noticeably smaller and paler to Nissl stain following 3 or 6 days' deprivation during the fourth week.5. Following 3 months of monocular deprivation, opening the eye for up to 5 yr produces only a very limited recovery in the cortical physiology, and no obvious recovery of the geniculate atrophy, even though behaviourally there is some return of vision in the deprived eye. Closing the normal eye, though necessary for behavioural recovery, has no detectable effect on the cortical physiology. The amount of possible recovery in the striate cortex is probably no greater if the period of eye closure is limited to weeks, but after a 5-week closure there is a definite enhancement of the recovery, even though it is far from complete.


Consequences of monocular deprivation on visual behaviour in kittens. 1. Kittens were raised for a period with one of their eyes closed by suture of the lids. The age at suture and the duration of deprivation were varied systematically. When the cat was a year or more old, the normal and deprived eyes were compared using behavioural procedures which made graded demands on visual function.2. In kittens deprived from birth, the duration of eye closure determined the severity of the defect in vision with the deprived eye. A cat with an eye closed for the first 4-6 weeks showed as a permanent effect only a lowering of the visual acuity. When closure was extended through the first 7 weeks the visual acuity was further lowered but the animal still showed good visual guidance of paw placement. Further extension of deprivation through the first 16 weeks led to a still more severe defect; such animals showed no indication of visual guidance of paw placement or of pattern discrimination. They were influenced visually by stimuli that differed in luminosity.3. The upper age limit of the susceptibility to deprivation was determined by varying the age at eye closure. Waiting until 1 month of age before closing the eye conferred no appreciable protection. Waiting until 2 months of age, however, reduced the damage. Deprivation starting at 4 months of age or later produced no effect we could detect. Thus, susceptibility is greatest during the second month after birth and then falls until by 4 months of age the kitten, like the adult cat, suffers no permanent consequences of monocular light and form deprivation.4. After exclusive use of the deprived eye for a period, brought about by closure of the normal eye, visual control with the deprived eye was better than in similarly deprived cats whose normal eye was never closed. Improvement in the deprived eye was also seen in an animal whose normal eye was closed after both eyes had been open for more than one year.5. Relating the behavioural results to the neurophysiological findings in the visual cortex in the same or similarly deprived cats shows that the grading of visual defects with age and length of deprivation was generally paralleled by a change in proportion of cortical cells driven by stimulation of the deprived eye. The effect of reversal of eye closure in improving behavioural control was not, however, accompanied by an increase in the ability of the deprived eye to drive cortical cells.


Heat production and chemical change in tortoise muscle. 1. Measurements have been made of heat production and changes in levels of phosphorylcreatine (PC), ATP and lactic acid resulting from contraction of tortoise muscle under anaerobic conditions.2. The only significant chemical change found was a break-down of PC.3. The amount of heat produced per mole of PC split (-DeltaH) was 13.18 +/- 1.04 kcal/mole (mean and S.E. from thirty-five observations).4. (-DeltaH) is probably rather greater in tortoise than in frog muscle. The value of (-DeltaH) cannot easily be accounted for by the known processes accompanying PC splitting in either type of muscle.


A servo-controlled pump perfusion system for the investigation of the various factors regulating blood flow in vascular beds.


The mechanical activity of the anterior mesenteric vein.


Influence of oestrogen on thyroid function in the ewe. 1. Thyroid activation at oestrus occurs in several species, which may be related to oestrogen secretion occurring at the same time. In the ewe this relationship has been examined by measuring thyroid activity before and after oestrogen administration.2. Measurements have been made of thyroid (131)I release rate and protein-bound (131)I concentration in the plasma in normal and ovariectomized ewes and of protein-bound (125)I in plasma from thyroid vein blood in ewes with exteriorized thyroid glands.3. No evidence of an activation of the thyroid by oestrogen was observed in immature ewes or adult oestrous cycle, anoestrous or ovariectomized ewes, given oestrone or oestradiol dibenzoate in doses of 25-1000 mug by injection.4. It was concluded that oestrogen may not be responsible for thyroid activation observed in normal oestrous ewes.


Autocancellation, a technique for identifying antidromic neurone potentials.


Real-time analysis of neurophysiological data using a PDP 9 computer.


A floating paired micro-electrode for intracellular recording and extracellular application of drugs by micro-iontophoresis on heart cells.


Irreversible impairment of thermoregulation induced by capsaicin and similar pungent substances in rats and guinea-pigs. 1. In rats and guinea-pigs a subcutaneous or intraperitoneal injection of capsaicin, the substance responsible for the pungency of red pepper, produces profound hypothermia associated with skin vasodilatation.2. After large doses of capsaicin rats and guinea-pigs become insensitive to the hypothermic action of capsaicin. This densensitization is apparently irreversible since it is present months after the capsaicin treatment.3. Capsaicin-desensitized animals are no longer able to protect themselves against overheating but respond with pronounced hyperthermia to high ambient temperatures (32-40 degrees C). Temperature regulation against cold exposure, however, is not impaired.4. They also respond with an enhanced hyperthermia to painful stimuli such as repeated pinching of the tail or repeated introduction of the thermometer probe into the rectum.5. The enhanced hyperthermias are not due to increased heat production but to impairment of the heat dissipating mechanisms, which in rats and guinea-pigs acts mainly through evaporation of saliva, and skin vasodilatation.6. Acylamides with pungent action related to capsaicin such as piperine, caprinoyl-p-aminophenol and propionyl vanillylamide also cause hypothermia followed by desensitization and their efficacy is dependent on their pungency. The non-pungent nonenoyl benzylamide produces neither hypothermia nor desensitization.7. Capsaicin and its related pungent acylamides appear first to stimulate and then to desensitize the hypothalamic warmth detectors. By stimulating them the acylamides evoke reflexly the hypothermic response, whereas after desensitization the protective thermoregulatory reflexes for heat dissipation are no longer activated in response to high ambient temperature and to painful stimuli.


Short-circuit current and ionic fluxes in the isolated colonic mucosa of Bufo arenarum. 1. The unidirectional fluxes of (22)Na, (36)Cl and [(14)C]bicarbonate ions were measured in paired portions of the isolated and short-circuited colonic mucosa of Bufo arenarum, separated from its muscular layer. Pharmacological effects as well as effects of changes in the composition of the nutrient solutions on the electrical parameters of membrane activity (potential difference, short-circuit current and total membrane resistance) are described.2. The net fluxes of both Cl and bicarbonate ions were not significantly different from zero in the absence of electrochemical gradients across the membrane.3. The net Na flux from mucosa to serosa represented a variable proportion of the short-circuit current ranging from 62 to 100%.4. The proportion of membranes with high discrepancies between net Na flux and short-circuit current decreased with the duration of captivity of the toads.5. When Na was entirely replaced by choline in the mucosal bathing solution, the short-circuit current dropped by a variable amount within the range of 64 to 98% of its control values in different membranes. This effect was completely reversible. Similar changes in the serosal solution had no effect.6. The short-circuit current and potential difference were very sensitive to the serosal concentration of bicarbonate ions. In different membranes, 60-100% of the short-circuit current was reversibly abolished by bathing the serosal surface with a bicarbonate-free solution. The mucosal bicarbonate level had no effect on either the potential difference or the short-circuit current. 5 mM bicarbonate in the serosal solution restored at least 50% of the short-circuit control value and full recovery was attained by concentrations near 30 mM bicarbonate.7. Anoxia brought the potential difference and short-circuit current reversibly down to zero in about 50 min.8. Ouabain reduced the short-circuit current up to 80% in about 40 min when present in the serosal solution at a concentration of 10(-4)M. At this or lower concentrations the ouabain effect was reversible. Above this level ouabain produced 100% inhibition in 3-4 hr, but this was no longer reversible. Ouabain had no effect on the short-circuit current either when applied to the mucosal surface or in the absence of Na from the mucosal solution.9. Diamox produced a variable inhibition of the short-circuit current of up to 30% only at concentrations above 10 mM.10. Possible mechanisms are discussed for the appearance of the non-Na component of the short-circuit current. A theory concerning its nature is proposed.


Bicarbonate secretion and non-Na component of the short-circuit current in the isolated colonic mucosa of Bufo arenarum. 1. In the isolated colonic mucosa of Bufo arenarum, under special circumstances, there is a variable fraction of the short-circuit current (0-38%) that is unaccounted for by either the Na or the Cl and bicarbonate transmembrane net fluxes.2. The hypothesis that a special kind of bicarbonate transport may account for the non-Na component of the short-circuit current was investigated. According to this, bicarbonate ions formed within the membrane await transport towards the mucosal solution within a compartment that does not undergo isotopic exchange with the serosal bathing solution. This kind of transport may be detected by a lowering of mucosal specific activity of bicarbonate but would not be revealed by the classic method of comparing the difference between the unidirectional fluxes with the short-circuit current.3. The specific activity of bicarbonate was determined in the inside solution (initially bicarbonate-free) of ten normal and four everted colonic sacs incubated in an external medium (reservoir) containing a constant specific activity of bicarbonate. Comparison between membrane-to-internal solution bicarbonate flux and non-Na component of the short-circuit current was carried out in two different ways: (a) by measuring the remaining short-circuit current in Na-free medium and (b) by determining simultaneously the Na net flux.4. Whatever the value of the short-circuit current and its non-Na component, there is no reduction of the specific activity of the bicarbonate appearing in the inside solution of the everted colonic sacs.5. In the normal sacs there is a reduction of the specific activity of bicarbonate which accounts for a membrane-to-mucosa bicarbonate flux which parallels the variations of the non-Na component of the short-circuit current although quantitatively representing only 68-87% of it.6. There is no systematic decrease in the rate of reduction of the mucosal specific activity of bicarbonate in successive experimental flux periods; this excludes a slow equilibration of the intracellular bicarbonate with serosal bicarbonate.7. Other possible explanations of the present results are discussed, as well as the availability and hydration rate of metabolic CO(2) necessary to account for this kind of bicarbonate transport.


Functional specializations of the vascular bed of soleus. 1. The venous outflow from the slow soleus muscle, at rest and during exercise, was compared with that of fast muscles. The blood flow through the soleus at rest was found to be, on average, 52 ml./100 g.min, which is about 4 times that of fast muscles.2. On stimulation of soleus through its motor nerve at low frequencies, up to 8/sec, hardly any increase in flow was observed, whereas fast muscles stimulated at the same rates showed a marked increase, the maximal functional hyperaemia being reached at 8/sec. Even when the soleus muscle was stimulated at frequencies of 40/sec the post-contraction hyperaemia was very small and sometimes absent.3. The relative absence of functional hyperaemia in the soleus does not appear to be due to low vascular tone, for small amounts of acetylcholine, injected close arterially, produced a considerable increase in blood flow. Further, in experiments in which the vascular tone was increased by lumbar sympathetic stimulation, no functional hyperaemia was seen. It is concluded that a contracting soleus does not release in adequate amounts the substance causing functional vasodilatation in fast muscles.4. No vasodilator effect of adrenaline could be demonstrated in soleus, and the vasodilator effect of isoprenaline was much smaller than that seen in fast muscles.5. The vasoconstrictor effect of lumbar sympathetic stimulation on the resistance vessels of soleus was much smaller than the effect seen in fast muscles. However, the responses of the resistance vessels in soleus to close arterial injections of noradrenaline were not very different from those of fast muscles, and it is suggested that the density of the terminal sympathetic innervation of the vessels of soleus differs from that of fast muscles.


Species and tissue variation in extraneuronal and neuronal accumulation of noradrenaline. 1. The ability of arterial and non-arterial smooth muscle in five tissues (vas deferens, heart, bladder, colon, spleen) in four species (mouse, rabbit, rat, guinea-pig) to accumulate and retain noradrenaline (NA) was measured in thin tissue slices exposed to NA for 30 min, then washed in cold saline solution for 30 min. NA accumulation was assessed histochemically by measuring the fluorescence brightness of the tissue with the Leitz MPV microphotometer. In addition, similar measurements were made on smooth muscle in the cat spleen, on cardiac muscle and on the terminal adrenergic nerves.2. In general, arterial smooth muscle had a greater capacity to accumulate and retain NA than non-arterial smooth muscle, but there was a great species and organ variability. The ability to accumulate and retain NA was best developed in the mouse, followed by the rabbit, rat and guinea-pig in that order. Among organs the artery to the vas and the coronary arteries showed the greatest retention. Among non-arterial smooth muscle the mouse vas and the rabbit colon were notable.3. Cardiac muscle accumulates NA during exposure to the amine but, unlike smooth muscle, cannot retain it when washed with NA-free solution.4. Terminal adrenergic nerves in different tissues show some variability in fluorescence intensity, and this is increased after exposure to NA. This may indicate a variable capacity of these cells to accumulate and retain NA.


The extraneuronal uptake and localization of noradrenaline in the cat spleen and the effect on this of some drugs, of cold and of denervation. 1. Extraneuronal uptake of noradrenaline (NA) was examined in the cat spleen first by perfusing with NA for 10 min, followed by a 2-min wash to clear the extracellular fluid, then measuring the amount retained, its subcellular distribution and the tissue components involved as revealed by the development of the characteristic fluorescence. Secondly, thin spleen slices were exposed to NA in vitro and the development of fluorescence in various structures, particularly arterial smooth muscle, measured.2. The cat spleen accumulated large quantities of NA and this, like the development of fluorescence, was concentration-dependent. After particle separation most of the retained amine appeared in the high-speed supernatant, with a lesser amount in the coarse granule fraction. There was little amine in either the mitochondrial or microsomal fraction. The microsomal fraction from unperfused spleens was rich in NA, presumably from storage granules from the adrenergic nerves. On an intermittent sucrose density gradient the NA-rich particles sedimented between 1.0 and 1.5 M sucrose, corresponding to the recently described dense granules from bovine splenic nerves.3. Fluorescence histochemistry revealed several tissues accumulating NA. At an NA concentration of 10(-5) g/ml., arterial smooth muscle and endothelium showed intracellular fluorescence; at 10(-4) g/ml., collagen, the perimeter of the smooth muscle cells of the capsule-trabecula-vein system and the reticular cells forming the framework of the spleen developed fluorescence. In the reticular cells the fluorescence was intracellular. The fluorescence pattern on the perimeter of non-arterial smooth muscle corresponded to the pattern of basement membrane as shown by PAS staining. The red pulp, lymphoid tissue and the phagocytic cells of the ellipsoids did not fluoresce.4. Cooling the tissue to 15 degrees C or less, phenoxybenzamine in a concentration of 5 x 10(-5) g/ml. or normetanephrine in a concentration of 10(-4) g/ml. prevented both uptake and loss of NA in arterial smooth muscle but had no effect on collagen.5. Chronic post-ganglionic denervation or reserpine had no effect on the development of fluorescence in any extraneuronal tissue.


Abomasal secretory responses to teasing with food and feeding in the sheep. 1. Secretion of acid and pepsin from abomasal pouches and contractions of the reticulum and rumen were studied in sheep. Observations were made in sheep after being fasted and when they had food available ad libitum.2. The abomasal pouches were of fundic regions alone and also of the fundic region with a rim of antral mucosa.3. The secretion from both types of pouch was continuous, was increased by feeding and decreased by fasting.4. The volume, pepsin concentration and acid concentration of the secretion from fundic pouches increased within 15-30 min of the sheep being teased with food or fed. These responses were observed in sheep which had food available ad libitum or had been fasted.5. Reticulum contractions and the rumen contractions associated with them (A sequences) increased in frequency when sheep with either type of pouch were teased with food or when they ate.6. Consistent associations between rumination and abomasal secretory activity were not established.7. Mixed fundic-antral pouches did not characteristically show responses to teasing with food and sustained secretory responses were delayed by up to 90 min after feeding commenced.8. It is suggested that a cephalic phase of gastric (abomasal) secretion was revealed in the studies on fundic pouches of the abomasum.


Depression of transmitter release at the neuromuscular junction of the frog. 1. Depression of transmitter release produced by preceding conditioning stimulation was studied at the frog's neuromuscular junction.2. Depression occurred when transmitter release was restricted to a short length of nerve terminal, or when release was initiated by electrotonic depolarization of the terminals after action potentials were abolished by tetrodotoxin.3. Quantitative studies revealed a non-linear relationship between the estimated magnitude of ;zero-time' depression and the amount of transmitter released by conditioning stimulation.4. Two stimuli separated by 20-200 msec were given and the ratio of the end-plate potential amplitudes (V(2)/V(1)) was measured. This amplitude ratio increased during depression produced by stimuli preceding the test pair.5. These observations may be explained by assuming that depression is associated with a reduction in release probability as well as a depletion of transmitter available for release.


Place and modality analysis in nucleus of posterior commissure. 1. Single units (157) responsive to somatic stimulation in the nucleus of the posterior commissure were examined in the cat under chloralose anaesthesia. 87.3% responded to stimulation of all four limbs, 2.4% to three limbs, 8.7% to two limbs and 2% to one limb.2. 44.7% of units could be activated by phasic hair movement; 52.4% responded additionally to auditory stimuli and 34.6% to visual stimuli, although there are marked differences in degree of heterosensory convergence between hair-sensitive units and others.3. Analysis by spike numbers and latencies show marked preference for contralateral limbs.4. Results are compared with those obtained under identical experimental conditions from units of the gigantocellular bulbar reticular formation, and show that anatomically discrete areas of the reticular formation are capable of differential analysis of afferent input.


Sympathetic denervation of the smooth muscle of the vas deferens. 1. The post-ganglionic nerve fibres to the vas deferens of the guinea-pig and rat were interrupted in vivo by stripping one vas deferens of its serous coat; the other vas deferens was left intact as a control.2. Four to eight days later the stripped vas deferens did not contract in response to electrical transmural stimulation in vitro at 0.1 msec pulse duration. Pulses of 1.0 msec duration produced small contractions which were not abolished by local anaesthetic or adrenergic neurone-blocking drugs.3. Log dose-response curves to noradrenaline were, for stripped vasa deferentia, to the left of those for control vasa. The increase in sensitivity to noradrenaline at 8 days was about sixteenfold for rat vasa and about tenfold for guinea-pig vasa. Tyramine did not contract stripped vasa from guinea-pigs or rats.4. The noradrenaline and adrenaline content of guinea-pig and rat vasa was greatly reduced or abolished 8 days after the stripping operation.5. Fluorescent nerve terminals were usually absent when transverse sections of stripped vasa were examined by fluorescence microscopy after treatment by the formaldehyde condensation method for demonstrating catecholamines.6. It is concluded that post-ganglionic sympathetic denervation is achieved by stripping the vas deferens in vivo of its serous coat and mesenteric attachments.


The effect of diet and acute starvation on the deiodination of thyroxine and triiodothyronine in the thyroidectomized rat. 1. General agreement exists that the level of thyroid function is depressed by starvation. The virtually complete cessation of biliary-faecal thyroxine loss in the starved animal makes the significance of this reduction difficult to assess in physiological terms.2. Deiodination of [(131)I]thyroxine was investigated in thyroidectomized rats. Thus central feed-back effects were eliminated and the changes in peripheral utilization of thyroxine could be observed. The simultaneous use of [(125)I] sodium iodide permitted changes in renal handling of iodide to be taken into consideration.3. Rats fed oxoid (Oxo Ltd. diet 41 B) deiodinated a significantly greater proportion of thyroxine in the 24 hr after injection of a tracer dose of [(131)I]thyroxine than did the starved or glucose-fed rat. [(131)I]triiodothyronine was also probably deiodinated at a faster rate in oxoid-fed rats than in starved or glucose-fed rats.4. Thyroxine was deiodinated at a faster rate by starved rats than by rats fed glucose.5. Thyroxine disappeared significantly faster from the blood in oxoid-fed than in the starved or glucose-fed rat. Thyroxine also disappeared faster from the blood in the starved rat than in the glucose-fed rat over 24 hr.6. These results are discussed in relation to previous findings of depressed pituitary-thyroid function in starvation.


Responses of cat retinal ganglion cells to brief flashes of light. 1. The responses of cat retinal ganglion cells to brief flashes of light have been illustrated and described with a view to providing material for comparison with psychophysical experiments in the scotopic (rod-dominated) range of performance.2. There is a minimum response duration of 50-70 msec no matter how brief the flash is made. This duration is reached with stimuli lasting 32 msec or shorter.3. Reducing the background illumination obviously increases the latency of responses to stimuli at 4 times threshold intensity (about 10 msec increment per log. unit decrement) but has no obvious effect on the minimum response duration.4. The relation between intensity and duration of a flash for threshold responses closely resembles that in human psychophysical experiments. The Bunsen-Roscoe law is applicable for flash durations up to 64 msec.5. If equal amounts of energy are delivered in the form of a pair of flashes of varying separation rather than by rectangular pulses, the shape of the response changes more abruptly with the temporal factor.6. Non-linear performance is apparent for stimuli as weak as 4 times threshold.7. A method is developed for quantitative analysis of individual responses. It is based upon cross-correlation of the train of impulses with a Gaussian smoothing function and represents local impulse frequency as a smooth function of time. The method also improves the signal-to-noise ratio of post-stimulus time-histograms of the sum of many responses.8. The measurement of variability of individual responses is the main result of the method; its magnitude indicates that it is a significant new factor limiting temporal resolution with suprathreshold stimuli.


Blood levels of oxytocin and vasopressin during suckling in the rabbit and the problem of their independent release. 1. Oxytocin and vasopressin were assayed in samples of blood collected from conscious rabbits during suckling. The milk yields were determined from the weight gain of the litters.2. With normal milk yields (35-155 g), relatively high concentrations (31-375 muu./ml.) of oxytocin were present in the blood but vasopressin was detected in only one out of eight samples. It is concluded that the release of oxytocin by the milk-ejection reflex is essential for normal milk removal in the rabbit and that this hormone is released independently of vasopressin.3. When the milk yield did not exceed 15 g, an amount which could be removed by passive withdrawal from the mammary gland, vasopressin was detected in four out of five blood samples but none contained a detectable concentration of oxytocin. This result can be explained by the intervention of emotional stress which is known to block the milk-ejection reflex but which acts as a stimulus for the release of vasopressin.4. Emotional stress could inhibit the milk-ejection reflex either centrally by blocking the release of oxytocin, or peripherally by blocking the response of the mammary gland to circulating oxytocin. The absence of the hormone in blood during ineffectual suckling suggests that the block is central.


Independent release of oxytocin and vasopressin during parturition in the rabbit. 1. Oxytocin and vasopressin were assayed in samples of blood collected from seven conscious rabbits during parturition.2. Oxytocin was detected in the blood in ten out of fourteen samples collected during the expulsion of one or more foetuses. Four samples contained 6-100 muu./ml., three 100-200 muu./ml. and three 200-500 muu./ml.3. Vasopressin was detected in six blood samples collected during the delivery of foetuses but in only one experiment did the amount exceed that found in the corresponding control sample collected before or after delivery.4. When both hormones were detected in the same blood sample, the ratio of oxytocin to vasopressin varied from 5:1 to at least 26:1.5. It is concluded that, while oxytocin may not be essential for parturition in the rabbit, stretching of the birth canal during the expulsion of foetuses normally acts as a stimulus for the reflex release of oxytocin from the neurohypophysis and that oxytocin is released independently of vasopressin.


The roles of striated and smooth muscle in the movement of the cat's nictitating membrane. 1. When the movement of the nictitating membrane is recorded in the usual way, pulled out under load in cat, dog, or rabbit, end-plate-depolarizing drugs such as succinylcholine, decamethonium, nicotine, and 2268F, cause a retraction.2. This movement is due to activation of orbital striated muscle, as evidenced by the resistance of the movement to ganglion block or excision of the superior cervical ganglion and to administration of phentolamine or atropine, and by its great sensitivity to dimethyltubocurarine.3. End-plate-depolarizing drugs produce contractions of the superior and inferior oblique and of the recti muscles strong enough to account for the movements of the nictitating membrane, provided the known fascial connexions of the orbit allow transmission of a fraction of the extraocular muscle movement to the membrane.4. In post mortem specimens with the front of the orbit undisturbed, retraction of the central end of any of the ocular muscles produces movement of the nictitating membrane; the movement was greatest with the superior oblique and medial rectus. In vivo, detaching the superior oblique from its insertion into the globe sometimes abolished or reduced the response to end-plate-depolarizing drugs.5. With the membrane unloaded and retracted into the medial canthus, in the lightly anaesthetized or unanaesthetized dog or cat, these drugs cause a protrusion of the membrane, which can be sufficient to cover the cornea. This response also resists ganglion-block and is highly sensitive to dimethyltubocurarine.6. It is suggested that in the normal conscious animal the nictitating membrane is held retracted by a relatively small amount of sympathetic activity, and that its protrusion is an active mechanism under voluntary control mediated by the striated muscles of the orbit.7. The importance of these mechanisms in the interpretation of experiments in which the nictitating membrane is used are discussed.


Recruitment for the military.

Recruitment for the military.


The biology of the atopic response.

The biology of the atopic response.


The plague on HMS 'Theseus', Jaffa 1799.


Spencer Wells--surgeon RN.

Spencer Wells--surgeon RN.


Actinomycosis of the body of the mandible.


An improved method of elevation of the injured hand.


Repair replication in Chinese hamster cells after damage from ultraviolet light.


Exciplexes and the fluorescence of Staphylococcus aureus endonuclease.


Photolysis of ethyl chloroacetate in liquid phase at 2537 A.


The effect of ultraviolet light on RNA metabolism in bromouracil deoxyriboside-grown HeLa cells.


Effects of ultraviolet radiation on the mitotic cycle and DNA, RNA and protein synthesis in mammalian epidermis in vivo.


Deuterium-isotope effect on the fluorescence yields and lifetimes of indole derivatives--including tryptophan and tryptamine.


The dye-sensitized photo-oxidation chemiluminescence of luminol.


Gradient formation of anthocyanin in seedlings of Fagopyrum and Sinapis unilaterally exposed to red and far-red light.


Differential, lethal and mutagenic action of 254nm and 320-400nm radiation on semi-dried bacteria.


Radiative and non-radiative losses in the retinol polyenes.


Electron spin resonance studies of the excited triplet states of DL-5-hydroxytryptophan, 5-hydroxyindole, 6-hydroxynicotinic acid, indole and hippuric acid.


Light induced synchronization of algal species that divide preferentially in darkness.


Number and distribution of chromophore types in native phycobiliproteins.


Red light interactions with blue and ultraviolet light in polarotropism of germlings of a fern and a liverwort.


Photoreactivation of killing in Streptomyces: action spectra and kinetic studies.


The photochemically induced reaction of sulfur dioxide with alkanes and carbon monoxide.


On the mechnaism of radiosensitization by 5-bromouracil. The occurrence of DNA strand breaks in U.V.-irradiated phage T4 as influenced by cysteamine.


Proflavine-sensitized photooxidation of methionine.


Flash-photolysis of chloranil as studied by electron spin resonance spectroscopy.


Photoaddition of dimethyl sulfoxide to polypeptides.


The pathogenicity of Fasciola hepatica in previously infected, corticosteroid-treated lambs.


Automatic sampling of blood and ruminal fluid of grazing sheep.


Further studies on experimental canine herpesvirus infection in young puppies.


The development of the embryonic membranes in the pig: observations on the afterbirths.


An estimation of the efficiency of the absorption of immune globulins from colostrum by newborn calves.


Kale anaemia. II. Further factors concerned in the occurrence of the disease under experimental conditions.


An experimental study of the causes of a nutritional and lactational stress infertility of pasture-fed cows, associated with loss of bodyweight at about the time of mating.


The effect of thyroidectomy and thyroparathyroidectomy upon phosphorus homeostasis in the goat: a hypothesis for the cause of hypophosphataemia.


Carbohydrate metabolism in newborn lambs and rats.


Experimental Erysipelothrix rhusiopathiae infection in white rats.


The preservation of Brucella melitensis Rev. I vaccine.


Investigations into a hepatotoxin in lupin roughage.


Two possible catecholamine metabolites in the secretion from ox skin.


Bright blindness in sheep. A primary retinopathy due to feeding bracken (Pteris aquilina).


Absorption of chloride from the rumen of the sheep.


The effect of treatment with emetine on sheep infected with immature Fasciola hepatica.


The effect of oral ammonium molybdate and sodium sulphate given to lambs with high liver copper concentrations.


Crystalline material from the feline bladder.


Experimental reovirus infection in dogs: a preliminary report.


The unsuccessful dialysis of scrapie agent from goat brain and spleen.


Biochemical changes following bilateral nephrectomy in the bovine.


The response of ponies to Myxovirus influenzae A-Equi-2. 3. The protective effect of serum and nasal antibody against experimental challenge.


Anthelmintic activity of parbendazole in swine naturally infected with lungworms and gastro-intestinal nematodes.


Function in cows with particular reference to the clearance of silicic acid.


Observations on hypertrophy of the liver in breeding ewes.


Intrapulmonary lymphoid tissue of healthy pigs.


The susceptibility of a dog kidney cell-line (MDCK) to canine distemper, infectious canine hepatitis and canine herpes virus.


The utilization of free amino acid and glucose carbon by sheep pregnant with twins.


The distribution of Herbst corpuscles in the foot of the domestic fowl (Gallus domesticus).


Adrenergic control of canine synovial perfusion in experimentally induced osteoarthritis and synovitis.


The efficacy of cambendazole against Ascaris suum and Strongyloides ransomi in swine.


Anaplasmosis transmission: inoculation by the ocular route.


Bacteriophage-like particles in the large intestine of the horse.


The effect of a conglutinin preparation on the haemolytic activity of streptolysin O.


The effect of dietary iodine on blood cholesterol levels in the dog.


The mind of the physician, or why lawyers have trouble with doctors.


The mind of the lawyer, or why doctors should not have trouble with lawyers.


Diagnoses from flocculation tests and other metabolic profile components. I. Cephalin flocculation.


The effect of home visitation on patient motivation to receive dental prophylaxis.


Experience with a new delivery system for dental care.


Crisis and solution in medical care.

Crisis and solution in medical care.


The determination of hyaluronic acid in synovial fluid.


Predictive medicine. I. Definitions.

Predictive medicine. I. Definitions.


Diagnoses from flocculation tests and other metabolic profile components. II. Thymol turbidity.


Expansion of health services in the medical center.


Characteristics of growth inhibition of Lactobacillus casei by 4-nitroquinoline-n-oxide. The bacteriostatic action of 4-nitroquinoline-n-oxide (4-NQO) for Lactobacillus casei is substantially reversed by d-and l-cysteine, glutathione, and 2,2-dihydroxy-1,4-dithiolbutane (dithioerythritol). The action appears to involve a chemical reaction between carbon atom 4 of 4-NQO and nucleophilic centers, such as -SH groups, located on essential cell constituents. The evidence presented indicates that the protective effect of d- and l-cysteine, glutathione, and dithioerythritol against the action involves reactions between 4-NQO and -SH compounds.


Enhanced immunogenicity in mice of a purified, tween-ether-treated influenza vaccine. The immunogenic response of mice vaccinated intranasally or subcutaneously with increasing doses of a purified, concentrated intact A(2)/Taiwan influenza vaccine or its Tween-ether derived vaccines was compared. Immunogenicity was measured by serum neutralization and hemagglutination-inhibition antibodies, lung lesions scores, and protection against respiratory challenge with live airborne influenza virus. Intact (untreated) vaccine, Tween-ether-treated (ET) vaccine, and the isolated hemagglutinins (HA) provided protection and stimulated homologous antibody response at the 35- and 70-chicken cell agglutination (CCA) unit level. At a lower dosage level, the vaccines administered by the subcutaneous route appeared to confer better protection. The ET vaccine was superior to intact virus or HA vaccines when administered subcutaneously. The minimum amount of the HA and intact vaccine given subcutaneously that protected mice against respiratory challenge was 7 CCA units (3.5 units injected twice) compared to 0.7 CCA units (0.35 units injected twice) for the ET vaccine. No heterologous antibody to the A/PR/8/34 or B/Mass/3/66 was noted. Low-level serum-neutralizing antibody was found against the A(2)/Japan/170 strain but, despite high levels of homologous A(2)/Taiwan/64 antibody, no cross-reactivity was found with the recent A(2)/Hong Kong/68 variant.


Enhancement of Friend leukemia virus infection in mice by Guaroa virus: quantitation and action of various oncogenic and nononcogenic viruses. Previous studies have indicated that Guaroa virus (GV), an arbovirus, enhanced the replication of Friend leukemia virus (FLV) in mice. To study further the interaction of GV and FLV, different levels of FLV activity were inoculated into mice. At a level of activity capable of producing limited splenic response, coinfection with GV resulted in a marked increase in spleen-foci activity, mean spleen weight, and amount of infectious virus recoverable from plasma and spleen of dually infected mice. Various oncogenic and nononcogenic viruses were also tested for their ability to enhance FLV infection.


Ester production by Pseudomonas fragi. IV. Demonstration of esterase activity. Assay of the esterase activity of sonically treated cell-free extracts, whole cell suspensions, and supernatant fluid of Pseudomonas fragi cultures with a differential respirometer revealed that the esterases were intracellular. Polyacrylamide-gel electrophoresis demonstrated six bands of esterase activity, which revealed substrate specificity differences. Band 1 exhibited slow mobility, bands 2, 3, and 4 moderate mobility, and bands 5 and 6 rapid mobility. Six bands were active with alpha-naphthyl acetate, four bands with alpha-naphthyl propionate, and 5 bands with alphanaphthyl butyrate. These esterases appeared to be more active with aromatic esters than with aliphatic esters.


Role of microbial iron transport compounds in bacterial spoilage of eggs. Microbial iron transport compounds, belonging either to the hydroxamate family excreted by pseudomonads, or to the phenolate family excreted by salmonellae, reverse the bacteriostatic effect of conalbumin on the growth of these bacteria in egg white. The presence of microgram quantities of these compounds permits both salmonellae and pseudomonads to reach dense populations in egg white. The role of these iron transport compounds in bacterial egg spoilage is discussed.


Gastrointestinal bacteria of certain Antarctic birds and mammals. An investigation was carried out of the aerobic gram-negative intestinal flora of 158 penguins, 30 skuas, and 66 seals from the Antarctic and sub-Antarctic zones and Phillip Island. Among penguins and seals, 17% and 11%, respectively, were devoid of aerobic enteric organisms, but microscopic examination showed the presence of other bacteria. The coliforms outnumbered the paracolons and nonlactosefermenting bacteria; irregular coliform types and Escherichia coli were predominant. The present study indicated the effect of diet on the composition of the intestinal flora of the birds and mammals examined.


Dry-heat inactivation kinetics of naturally occurring spore populations. Twenty-three soil samples were collected from areas of the United States where major spacecraft assembly and launch facilities are in operation. Soil samples were treated with ethyl alcohol, ultrasonic energy, and gross filtration. The resultant suspensions consisted of viable, naturally occurring bacterial spores and were used to inoculate stainless-steel strips. The strips were suspended in a forced air oven and assays were made at 5-min intervals for the number of viable spores. Most survivor curves were nonlinear. Subsequently, spore crops of heat-sensitive and heat-resistant soil isolates were found to have linear survivor curves at 125 C which were unaffected by the presence or absence of sterile soil particles from the parent sample. When two spore crops, one of which was heat-resistant and the other heat-sensitive, were mixed, the resultant nonlinear curves were unaffected by the presence or absence of sterile parent soil. Therefore, the survivor curves obtained originally with the soils were the result of heterogeneous spore populations rather than of protection afforded by soil particles in our test system. These results question the rationale both of assuming logarithmic death and of using decimal-reduction values obtained with subcultured standard reference spores in the derivation of dry-heat sterilization cycles for items contaminated with naturally occurring spore populations.


Comparison of macrocomplement and microcomplement fixation techniques used in fungus serology. A comparative evaluation was performed on the micro- and macrocomplement fixation (CF) tests that are used as standard procedures in the serodiagnosis of blastomycosis, coccidioidomycosis, and histoplasmosis. Tests with 937 sera from suspected and culturally proven cases of these diseases against yeast-form antigens of Blastomyces dermatitidis and Histoplasma capsulatum and against the soluble antigens, coccidioidin and histoplasmin, revealed that the microtiters were within +/- 1 dilution of the macrotiters in 83 to 93% of the sera. Tests on randomly coded quality control sera revealed the microform of the CF test to be highly reproducible. Our studies indicate that the results obtained by the two tests have similar diagnostic and prognostic interpretations. Because of the sensitivity, reproducibility, economy, and ease of performance, the microtest is highly recommended for use in fungus serology.


Microbiological assay for estimating salivary concentrations of the cariostatic antibiotic Actinobolin. A logarithmic-ratio microbiological assay has been developed for the estimation of concentrations of actinobolin (or inhibitory equivalents) in human saliva. The utility of this assay has been demonstrated by presenting data that show concentrations of this antibiotic (or inhibitory equivalents) detected in saliva or saline after incubation at 37 C for periods as long as 6 hr. The results of some statistical analyses of the assay data have been included.


Immunofluorescent identification of Type 12 group A streptococci. The fluorescent antibody (FA) conjugate prepared by labeling streptococcal M type 12 antibody with fluorescein isothiocyanate was found to exhibit considerable nonspecific FA staining with other group A M-serotypes. The cross-reactions could be reduced sufficiently or eliminated by the addition of adsorbed homologous blocking serum (AHB) but not by preimmune serum. The AHB was prepared by adsorbing type 12 antiserum with untreated homologous cells. Comparative staining with unblocked and AHB-blocked FA conjugates enabled type 12 streptococci from clinical specimens to be rapidly and accurately identified.


Potential of kidney cell cultures from nonhibernating thirteen-lined ground squirrels (Citellus tridecemlineatus) for virus propagation. Kidney cells were cultured in vitro from nonhibernating thirteen-lined ground squirrels (Citellus tridecemlineatus). These primary ground squirrel kidney cultures were tested for the ability to support the replication of 13 viruses representing nine virus groups. The cultures were shown to be susceptible to every virus tested, either by an increase in infectious virus or by the cytopathic effect produced.


Pyelonephritis therapy in rats: random association with excreted urinary antibacterial activity. In vitro activities or excreted urinary activities of 56 generic and experimental drugs against two organisms commonly associated with human pyelonephritis, Escherichia coli and Proteus mirabilis, are not correlated with the in vivo activities of these compounds as measured by reduction of viable organisms in kidneys in experimental pyelonephritis.


Bacterial degradation of diphenylmethane, a DDT model substrate. A strain of Hydrogenomonas was isolated by elective culture in a solution with diphenylmethane, an analogue of DDT, as the sole carbon source. Constitutive enzymes effected the oxidation and fission of one of the benzene rings of diphenylmethane, and phenylacetic acid was found as a major degradation product. Small amounts of phenylglyoxylic and benzoic acids were also generated from diphenylmethane by the bacterium. Phenylacetic acid, which contains the second benzene ring of diphenylmethane, was metabolized by inducible enzymes.


Growth of Rio Bravo virus in cell cultures. The growth of Rio Bravo virus (RBV) in eight cell culture systems was studied. Highest yields of virus were produced in BHK-21 (C13), L, and Vero cell lines, but L cells were resistant to low doses of virus. LLC-MK(2), HeLa, and human embryo skin cells produced moderate amounts of virus, but FL amnion and primary chick embryo fibroblasts supported little virus growth. Virus was rapidly inactivated by exposure to pH values below 7.0. Single-cycle growth in BHK-21, L, and LLC-MK(2) cell monolayers was characterized by a latent period of about 12 hr followed by rapid virus production that peaked at 36 to 48 hr. Vero cell cultures can remain chronically infected with RBV for more than 100 days. Such cultures show evidence of cell destruction, and their supernatant fluids contain virus at 10(4) to 10(5) log(10) per ml.


Evaluation of systemic antifungal agents in X-irradiated mice. The effect of X irradiation on the survival time of animals experimentally infected with pathogenic fungi was studied, and the activity of antifungal agents in pre-irradiated hosts was evaluated. A 24-hr preinfection dose of X irradiation decreased the survival time of mice infected with Cryptococcus neoformans and Histoplasma capsulatum to a greater extent than Candida albicans or Blastomyces dermatitidis infections. Exposure to 400 r caused a significant reduction in the variation (S(2)) survival time of C. albicans or H. capsulatum mouse infections. A single 100-mg/kg dose of 5-fluorocytosine or amphotericin B administered within 24 hr postinfection significantly extended the survival time of mice infected with C. albicans. Delayed treatment with amphotericin B was effective against C. neoformans infections. Four 50-mg/kg doses of 5-fluorocytosine were more effective than a single 200-mg/kg dose against C. neoformans infections. A single dose of amphotericin B provided significant protection when administered 48 hr postinfection against B. dermatitidis in preirradiated mice. A single dose of saramycetin 48 hr postinfection was highly effective against H. capsulatum mouse infections. A 100-mg/kg dose of amphotericin B was only effective against this fungal pathogen when administered within 8 hr postinfection. In vivo activity of the antifungal agents studied was detected within 8 to 14 days. The relative in vivo activity of several antifungal agents indicated the importance of considering their individual pharmacological properties for optimum effectiveness. The experimental model used in this study should be useful for the detection and for the preclinical evaluation of new antifungal agents.


Susceptibility of Pseudomonas aeruginosa to carbenicillin. Ninety clinical isolates of Pseudomonas aeruginosa were examined for susceptibility to carbenicillin by the broth dilution and disc diffusion methods. Inhibition zone diameters varied at given minimal inhibitory concentration levels of the antibiotic. Nevertheless, the results obtained allowed the proposal of the following tentative criteria for the interpretation of inhibition zones. Pseudomonadaceae yielding zones of inhibition measuring at least 10 and 16 mm in diameter around 25-and 100-mug discs, respectively, are sensitive to this antibiotic when examined by the standardized Bauer-Kirby method of disc susceptibility testing. Isolates characterized by zones of less than 100 mm in diameter around 25-mug discs should be tested with 100-mug discs before they are reported as sensitive or resistant to carbenicillin.


Examination of virus-infected cultured cells by scanning electron microscopy. The scanning electron microscope (SEM) was used to detect changes in morphology of BSC-1 cells after infection with vesicular stomatitis virus (VSV) or herpes simplex virus. The morphological changes of the infected cells were related to the length of time of infection and to the virus used. Extensive alteration to the cytoplasm could be seen 24 and 48 hr after infection with 10 and 320 TCID(50) of VSV. Within 24 hr after infection with 1 TCID(50) of herpes simplex, a few nuclei were swollen. However, 72 hr after infection with 100 TCID(50) of herpesvirus, many nuclei were swollen and appeared in large aggregates, probably representing formation of a polykaryocyte. Corresponding samples stained with May-Grunwald-Giemsa were observed in the light microscope and morphological changes were compared to those seen with the SEM.


Sensitivity of the plaque technique for the study of selected vaccine strains and a virulent strain of Newcastle disease virus. A plaque technique was found useful for the differentiation and titration of two vaccine strains and a local highly virulent field isolate of Newcastle disease virus.


Determination of niacin in orange juice with lyophilized Lactobacillus arabinosus ATCC 8014. The determination of niacin in orange juice with lyophilized Lactobacillus arabinosus ATCC 8014 has the advantage over the usual method in eliminating the delay caused by the necessity of cultivating cells of L. arabinosus for the inoculum and also in eliminating the periodical cultivation on agar slopes.


Differentiation of Brucella canis from other brucellae by gas chromatography. Gas chromatographic techniques allow for differentiation between a strain of Brucella canis and strains of other brucellae.


Effects of alkylbenzene sulfonates on yeasts. Species of Hansenula and Candida are resistant to high concentrations of anionic alkylbenzene sulfonates and degrade subinhibitory concentrations of these detergents.


Utilization of n-alkanes by Pullularia pullulans. Pullularia pullulans was tested for its ability to utilize a series of n-alkanes for growth. It utilized hydrocarbons containing higher C-numbers (13, 14, 16, and 18) to a greater degree than those containing lower numbers; in addition, an induction phenomenon was noted. Gas-liquid and thin-layer chromatography of ether extracts of the growth media revealed that oleic and palmitic acids were formed from tridecane, tetradecane, hexadecane, and octadecane.


Multiple assessment and serum neutralization of arbovirus mixtures. Mixtures of Venezuelan equine encephalomyelitis, Rift Valley fever, and chikungunya viruses may be assayed by selective immunofluorescence staining of infected cell monolayers. A multiple serum neutralization test is described for quantifying reactions of these viruses with mixtures of serum antibodies.


The pH dependence of the ageing of a phosphonylated acetylcholinesterase: evidence for the catalysis by a carboxyl group.


The reactivity of group-specific chromophoric reagents.


An x-ray study of the product of an unusual reaction in lysozyme.


Selective photo-oxidation of amino acids in proteins.


The biological role of the haem group in haemoglobin.


Pulse radiolysis: an oxidative-reductive probe in general biochemical and enzyme studies.


Functional sulphydryl groups in enzymic catalysis.


The masking of a membrane bound enzyme catalysing disulphide interchange by polysomes: effects of steroid hormones and aflatoxin B1 on the system.


Selective reactivity of thiol groups in proteins.


Stoicheiometric, reactivity and environmental probes for sulphydryl groups in enzymes.


The reactivity of thiol groups in aldolase.


Imidazole and proton transfer in catalysis.


Imidazole catalysis in model reactions for serine peptidase and cysteine peptidase activities.


Catalysis by carboxyl groups.

Catalysis by carboxyl groups.


Steric assistance for intramolecular catalysis.


Letter to the editor: Immediate hysterectomy and suspicious curettings.


Gross splenomegaly and pancytopenia.

Gross splenomegaly and pancytopenia.


Oxygenator: Bayeux-Richard.

Oxygenator: Bayeux-Richard.


Drivers and road signs.

Drivers and road signs.


A comparison of work-load using physiological and time study assessments.


Pilot response in flight and simulated flight.


Internship programmes in professional preparation.


A profile of the internship training programme in preventive and social medicine--all India Institute of Medical Sciences.


An approach to interns' training in rural areas.


Drugs and the newborn.

Drugs and the newborn.


Maternity unit. An experiment in very early discharge at the North Tees Hospital.


Trials with oral B.C.G.

Trials with oral B.C.G.


Innominate science, the specialty of general practice.


Music at night. An experiment in a geriatric ward.


Physicians' involvement with industrial productivity.


Actions of TMA in continuing education.

Actions of TMA in continuing education.


Universal health insurance.

Universal health insurance.


High resolution cinematography at high temperature in the electron microscope.


Stereo height measurements in scanning electron microscopy.


A coupled photometer and respirometer.

A coupled photometer and respirometer.


Studies on leishmaniasis in Ethiopia. II. Laboratory culture and biology of Phlebotomus longipes (Diptera: Psychodidae).


The effect of infection with Brugia pahangi on the flight of Aedes aegypti.


Onchocerca-Simulium complexes. VI. Experimental studies on the transmission of Venezuelan and West African strains of Onchocerca volvulus by Simulium metallicum and S. exiguum in Venezuela.


Erythrocyte reduced glutathione in malaria (Plasmodium berghei and P.knowlesi).


Electron microscopy of Entamoeba histolytica in host tissue.


Studies on the role of adenosine phosphates in erythrocytes of Plasmodium knowlesi-infected monkeys.


Resistance to superinfection with Plasmodium berghei in mice in which the original infection was suppressed by a milk diet.


Anthelmintic activity of pyrantel and morantel against adult and larval stages of Nippostrongylus brasiliensis and Nematospiroides dubius.


Postgraduate medical studies in Poland.

Postgraduate medical studies in Poland.


Vocational training for general practice: some problems of implementation.


Clinical tutors in psychiatry.

Clinical tutors in psychiatry.


Learning environment of a medical school: expectations versus perceptions of a first-year class.


The undergraduate curriculum in retrospect.


Advantages and disadvantages of closed-circuit television in the teaching of large classes in preclinical medicine.


Journalized course instruction. A model plan and its application to a course in neuroanatomy.


Relationship of pore size and surface area to quantity of stabilized enzyme bound to glass.


Purification and properties of human brain mitochondrial monoamine oxidase.


Some catalytic properties of purified gamma-amino-butyrate-alpha-oxoglutarate transaminase from the rat brain.


Salivary amylase activity in a millipede.


Purification and properties of guanine-deaminase from rat kidney.


Inhibition of tryptamine oxidation by N'-dimethylaminosuccinamic acid (B-995) and maleic hydrazide (MH).


Effect of temperature and triton X-100 on the activity of particulate neuraminidase from rabbit brain.


Samuel Wilks.

Samuel Wilks.


Capillary embolism or arterial pyaemia by Samuel Wilks.


Alkaptonuria.

Alkaptonuria.


Structure of Hygromycin B, an antibiotic from Streptomyces hygroscopicus: the use of CMR. spectra in structure determination, I.


Design and analysis of sampling plans to estimate aflatoxin concentrations in shelled peanuts.


The deposition of polyunsaturated fatty acids in the rat fed partially hydrogenated vegetable oil.


Gas-liquid chromatography of amino acids in biological substances.


The effect of salts on the derivatization and chromatography of amino acids.


Trimethylsilylation of amino acids. Effect of solvents on derivatization using bis(trimethylsilyl)trifluoroacetamide.


Gas chromatographic analysis of fecal pollution sterols on a single combined packed column.


Chromatography of adrenocortical steroids on silicic acid columns.


Column chromatography of the bromo-mercuri-methoxy adducts of fatty acid methyl esters as a means of isolating polyenoic acids present in low concentrations.


The separation of free dicarboxylic acid porphyrins using thin-layer and paper chromatography.


Development and comparison of thin-layer chromatographic and gas-liquid chromatographic methods for measurement of methimazole in rat urine.


The application of thin-layer electrophoresis and chromatoelectrophoresis on Sephadex G-25 to the analysis of amino acid and peptide composition of biological fluids.


Direct gas chromatographic estimation of lower alcohols, acetaldehyde, acetone and diacetyl in milk products.


The determination of picloram in fescue by gas-liquid chromatography.


The retardation of certain proteins during chromatography on tanned gelatin.


Manganous chloride spray reagent for cholesterol and bile acids on thin-layer chromatograms.


Separation of Planavin herbicide and some related compounds by two-dimensional thin-layer chromatography.


A thin-layer chromatographic limit test for the detection of anhydrotetracycline and 4-epi-anhydrotetracycline in tetracycline.


Paper chromatography of 3-methylhydantoic acid and 1-methylhdantoin, possible intermediates of microbial degradation of creatine and creatinine.


Differentiation of phenothiazine derivatives by locating agent on thin-layer chromatographic plates.


A rapid chromatographic procedure for the detection of some diuretics in pharmaceuticals and biological fluids.


Medicine at law.

Medicine at law.


A simple, inexpensive aerosol generator.


Malaria: a persistent problem for civilian physicians in 1971.


Myocardial infarction: ventricular tachycardia.


Occupational medicine.

Occupational medicine.


Cell mediated immune response. Current concepts and approaches.


A wind tunnel for environmental studies on small animals.


The foetus and its membranes.

The foetus and its membranes.


Diffuse lighting for infra-red photography in medicine.


Half-skull acrylic models.

Half-skull acrylic models.


Composite rapid sections of whole organs on paper.


Vision and the eye--an historical vignette.


Polaroid photography in ophthalmology.

Polaroid photography in ophthalmology.


Photographic standardization chart.

Photographic standardization chart.


The simple production of large bromide prints ('photo-murals').


Marihuana.

Marihuana.


Central vs. peripheral catecholamines in rats during adaptation to chronic restraint stress.


Action of lycopene in the experimental gastric ulcer.


Investigations on induction of neutrophilic granulocystosis and toxicity of Cleistanthin-CIBA Go.4350--a new glycoside from Cleistanthus collinus (Roxb).


Effects of (--) delta-9-trans-tetrahydrocannabinol and a synthetic derivative on maze performance of rats.


Evaluation of diets in relation to nutritional status.


Experimental protein-calorie deficiency.


Nutritional anaemias.

Nutritional anaemias.


Host--parasite relations: nutrition and genetics in filariasis.


The future of animals as sources of human food. Pigs--whither?


A behavioural approach to organoleptic properties of food.


The future pattern of food consumption and marketing.


Instrumental assessment of food appearance.


Instrumental methods for evaluating food texture.


Some aspects of the measurement of flavour.


On making food attractive.

On making food attractive.


Food selection by ruminants.

Food selection by ruminants.


Flavours of dairy products.

Flavours of dairy products.


Food preference in domestic pets.

Food preference in domestic pets.


The complex background to the sensory qualities of meat and fish.


Some rheumatological emergencies.

Some rheumatological emergencies.


The nature of nasolabial gland secretion (NLGS) in large domestic tuminants.


The fine structure of bovine gastric epithelia.


The effect of intravenous infusion of dopamine on the unesterified fatty acids of sheep plasma.


The recovery of immunoglobulin G from horses by combination of selective plasmapheresis and forced flow electrophoresis.


A post-mortem survey of the relationships between bile staining and ulceration of the oesophageal portion of pig's stomach.


Multiplication of Salmonella in liquid feed and its influence on the duration of excretion in pigs.


Trichostrongylus axei host-parasite relationship studies. The influence of passage on cross infection.


Genetic differences in the susceptibility of sheep to infection with Trichostrongylus axei. A comparison of Scottish Black-face and Dorset breeds.


The pathology of pneumonia in young lambs inoculated with Bedsonia.


Contagious agalactia of sheep and goats. The serial passage in goats of an attenuated strain of Mycoplasma agalactiae AIK40.


Contagious agalactia of sheep and goats. A comparison of 2 Turkish strains of Mycoplasma agalactiae by cross protection tests in goats.


Anaphylaxis in young calves inoculated with heat-inactivated Mycoplasma mycoides.


The use of mature sheep in anthelmintic tests. A hazard of the controlled test.


A critical test of morantel pamoate against Ancyclostoma caninum in dogs.


Resting oxygen consumption in chicks infected with intestinal coccidiosis.


Ifection of Rhipicephalus appendiculatus ticks with Theileria parva, using a rabbit's head perfusion technique.


Multiplication of scrapie agent in cell culture.


Experimental acute toxicity of orally administered sodium selenite in lambs.


Pulmonary alveolar surfactant in irradiated lung of rat.


Effect of oleic and linoleic acids on the monodesaturation in vitro of stearic acid by the livers of patients suffering from malignant neoplastic diseases.


Autoadaptation mechanism of the human body.


Hyperglycinemia and propionate carboxylation.


Host response and biologic differentiation of Nippostrongylus brasiliensis.


Changes in muscle ultrastructure in diabetes mellitus.


A biomechanical evaluation of knee stability in below knee braces.


Vectors of Theileria hirci in south and southeast of Iran.


To teach or not to teach family planning in Kenyan primary schools.


Myoelectric control sites for upper-extremity devices.


The influence of custom and tradition on maternity care in Ankole District. A report to the Maternal and Child Health Advisory Committee of the Ministry of Health, Uganda.


Estimation of maturity by roentgen studies of ossification centres in African newborn infants.


Phlebitis following intravenous infusion.


Penicillamine as an adjuvant to antimonial therapy, effect on electrocardiographic changes in dogs.


The energy budget of man at high altitudes.


Acclimation to heat of the beagle dog.

Acclimation to heat of the beagle dog.


Vital issues in computing decompression schedules from fundamentals. I. Critical supersaturation versus phase equilibration.


Behavior and physiology of mice in a closely controlled environment.


Comparison of the reproductive performance of rats at high altitude (3,800 m) and at sea level.


Cell association and somatic cell hybridization.


Lysosomes and storage diseases.

Lysosomes and storage diseases.


Microtubules in disk-shaped blood cells.


An analysis of coital patterns.

An analysis of coital patterns.


Perceived clarity of individual job objectives and of group mission as correlates of organizational morale.


Relationships of speaker-message perception to perceptual field-independence.


Individual differences in perceptions of the college environment.


Pretest and posttest reactions to self-viewing one's teaching performance on video tape.


The influx of orthophosphate into squid giant axons. 1. The influx of (32)P, applied externally as orthophosphate, into the axoplasm of squid giant axons has been studied.2. An average orthophosphate influx of 20.9 f-mole/cm(2).sec is obtained if the (32)P found in the axoplasm is assumed to be indicative of orthophosphate which has crossed the axolemma.3. The influx does not show very much dependence on external orthophosphate concentration in the range 0.02-0.5 mM.4. The influx is reduced by cyanide, 2,4-dinitrophenol, ouabain and by the absence of external potassium.5. The (32)P appears to arrive in the axoplasm as orthophosphate.6. It is concluded that there is an inward movement of orthophosphate into the axons which is mediated by an active transport process and that this may have some connexion with the active transport of sodium and potassium.


The effect of duodenal and mid small bowel transection on the frequency gradient of the pacesetter potential in the canine small intestine. 1. The effect of surgical transection and reunion of the small bowel on its pacesetter potenial (PP) frequency gradient was studied over periods of 3 months in six conscious, healthy dogs, using fourteen platinum electrodes previously implanted along the bowel.2. Duodenal transection and reunion abolished the gradient of the pacesetter potential distal to the transection and this effect persisted throughout 3 months of observation.3. In dogs with two transections, one in the duodenum and another in the mid small bowel, the mid small bowel transection and reunion further reduced the frequency of the PP caudad to it and this effect also persisted throughout the 3 months of observation.4. We conclude that the gradient in intact bowel occurs because the frequency of the duodenal pace-maker is considerably more rapid than the natural frequency of the PP in the rest of the bowel, and because the bowel is composed of collections or populations of smooth muscle cells with differing natural or intrinsic PP frequencies arranged in a progression of diminishing frequencies from orad to caudad location. The natural frequency of a segment is unmasked by transection of the bowel just orad to it because this eliminates the influence or drive of the orad pace-maker. The findings are in agreement with the concept that in intact bowel, as the PP passes caudadward, distal populations of cells are eventually encountered which cannot follow the faster orad pacesetter because of the slowness of their natural frequency. Thus, during caudad passage, some cycles of the PP are not transmitted and this, occurring over the length of the bowel, accounts in part, at least, for the gradient of frequency of PP over the small bowel.


The coupling of downhill ion movements associated with reversal of the sodium pump in human red cells. 1. Previous work on the incorporation of inorganic phosphate (P(i)) into ATP has suggested reversal of the chemical reactions of the Na pump in human red cells. A study has now been made of the associated movements of Na and K.2. The efflux of K, and the influx and efflux of Na were measured. When the Ringer was without K, the loss of cell K was inhibited by ouabain, and the ouabain-sensitive component of K efflux (0.36 mu-equiv.ml.(-1).hr(-1)) required external Na.3. The exchange of Na was also inhibited by ouabain. When influx and efflux of Na were measured simultaneously in K-free Ringer there was an excess of ouabain-sensitive influx over efflux of about 0.36 mu-equiv.ml.(-1).hr(-1). This difference balanced the ouabain-sensitive K efflux, and was not found with 10 mM-external K. The Na and K movements appear to be coupled and to be mediated by reversal of the Na pump.4. The net uptake of Na sensitive to ouabain was 0.38 mu-equiv.ml.(-1).hr(-1) for red cells incubated in K-free Ringer, and the net loss of K under the same conditions was 0.58 mu-equiv.ml.(-1).hr(-1) in rough keeping with the unidirectional flux values.5. Oligomycin decreased Na influx and efflux to the same extent as ouabain.6. There appears to be a coupled downhill movement of Na and K that is abolished both by inhibitors of the Na pump and by external K which promotes normal transport of Na outwards and K inwards.


The secretory pattern of three stomach preparations in the rat. 1. In conscious rats provided with a gastric fistula, or a Pavlov pouch, or a Heidenhain pouch, the secretion of acid and pepsin was studied in the interdigestive state and in response to hog gastrin II. In Pavlov pouches and in Heidenhain pouches the responses to 2-deoxy-D-glucose and to food were established, as were also the responses to gastrin pentapeptide and methacholine in Heidenhain pouches.2. Interdigestive secretion of acid and pepsin is substantial in the gastric fistula and the Pavlov pouch preparation, whereas in the Heidenhain pouch acid secretion is low or scanty, and the ratio pepsin/acid output is higher than in the innervated preparations.3. Feeding evoked secretion of acid and pepsin in the Heidenhain and Pavlov pouches; the increase in pepsin secretion lasted much longer in the Heidenhain than in the Pavlov pouch.4. Methacholine, infused in a threshold dose, augmented the acid output in response to food in the Heidenhain pouch, but did not affect the pepsin output.5. Gastrin II (hog) evoked graded acid responses in the three stomach preparations, and the innervated preparations were more sensitive to gastrin II than the denervated one, whereas stimulation of pepsin secretion was apparent only in the Heidenhain pouch.6. Methacholine, on infusion, in the Heidenhain pouch, gave a maximal acid secretory response, greater than twice that obtained by gastrin, and produced strong stimulation of pepsin.7. Methacholine, infused in a threshold dose, accentuated the acid secretory response to graded doses of gastrin.8. 2-deoxy-D-glucose stimulated acid and pepsin secretion consistently in the Pavlov pouch, whereas in the Heidenhain pouch the response was scanty or absent.9. A large dose of gastrin pentapeptide injected intravenously while a background secretion was maintained by gastrin II, produced in the Heidenhain pouch triphasic changes in the sequence: stimulation, inhibition, stimulation.


Regional variations in the visual acuity for interference fringes on the retina. 1. The visual acuity of the peripheral retina was measured using both sinusoidal gratings viewed in the usual way and interference fringes formed on the retina directly.2. It is shown that optical aberrations cause a reduction in peripheral visual acuity for eccentricities of less than 5 degrees . However, the hypothesis that optical defects are a major cause of the well-known decrease in acuity with eccentricity is rejected.3. The fringe acuities at various retinal positions are compared with Osterberg's counts of the distribution of cones. It is shown that at eccentricities of less than 2 degrees , resolution approaches the theoretical limits for a mosaic of receptors.


The effect of altered thyroid state on atrial intracellular potentials. 1. A group of rabbits was made hypothyroid by thyroidectomy, and another group was injected daily with L-thyroxine. After an appropriate interval respective alterations in thyroid state were confirmed by measurement of heart weight and of plasma iodine, and the animals' atria were isolated for recording.2. Measurements were made of atrial contractions, conduction velocity, spontaneous heart rate and maximum driven frequency, and action potentials were recorded with intracellular micro-electrodes.3. The resting potential and action potential heights were not affected by differences of thyroid state.4. Atrial arrhythmias are common in hyperthyroidism, rare in myxoedema. The possibility that hypothyroidism might reduce the rate of rise of the action potential, as do anti-arrhythmic drugs, and hyperthyroidism increase it, was investigated. Although the rate of rise was slower in hypothyroid atria at some driving frequencies, this could not alone account for an anti-arrhythmic effect, because at frequencies near the spontaneous heart rate the rate of rise of the action potential was not reduced.5. The duration of the repolarization phase of the action potential was greatly prolonged in atria from thyroidectomized rabbits, and was shortened in hyperthyroid atria. These changes could account for a reduced probability of arrhythmias in hypothyroidism, and the converse in hyperthyroidism.


Reversal of the potassium entry mechanism in red cells, with and without reversal of the entire pump cycle. 1. (42)K has been used to study the ouabain-sensitive component of potassium efflux from intact human red cells.2. Ouabain-sensitive efflux of potassium was observed only in media containing either sodium ions in moderate or high concentration or potassium ions.3. The effects of sodium and potassium in the medium were not additive. Potassium ions always increased the ouabain-sensitive potassium efflux, but in media containing 4.2 mM-K an increase in sodium concentration from 4.5 to 131 mM had little effect.4. In potassium-free media, ouabain-sensitive potassium efflux increased roughly linearly as the external sodium concentration was increased from 35 to 155 mM.5. The sensitivity of potassium efflux to external potassium depended on the concentration of sodium in the medium. In a 5 mM-Na (choline) medium, ouabain-sensitive potassium efflux was half-maximal at about 0.27 mM-K. In a 150 mM-Na medium the effect of potassium was half-maximal at about 1 mM-K. The relation between external potassium concentration and ouabain-sensitive sodium efflux was similarly influenced by the concentration of sodium ions in the medium.6. Inosine greatly reduced the ouabain-sensitive efflux of potassium into both 5 mM-K and potassium-free media. It probably acted by reducing the intracellular phosphate concentration to a low level.7. Ouabain-sensitive potassium efflux was not affected by the concentration of inorganic phosphate outside the cells and was not associated with a ouabain-sensitive efflux of phosphate of comparable magnitude. A small associated efflux could not be excluded.8. Simultaneous measurements of sodium efflux and of potassium efflux from identical batches of cells incubated in potassium-free media showed that inosine reduced ouabain-sensitive potassium efflux at the same time as it increased ouabain-sensitive sodium efflux.9. When cells that had been largely depleted of energy stores by pre-incubation with 2-deoxyglucose were incubated in high-sodium media, with and without potassium, it was observed that potassium in the medium increased the ouabain-sensitive potassium efflux but reduced the ouabain-sensitive efflux of sodium.10. Simultaneous measurements of the ouabain-sensitive efflux of potassium and influx and efflux of sodium across the membranes of starved cells incubated in potassium-free media, with and without inosine, suggested that ouabain-sensitive potassium efflux was associated with a net ouabain-sensitive entry of sodium.11. The results are best explained by supposing that the ouabain-sensitive efflux of potassium does not reflect lack of discrimination by the mechanism responsible for sodium expulsion, but is brought about by the reversal of steps in the pump cycle normally responsible for potassium entry.


Synthesis of adenosine triphosphate at the expense of downhill cation movements in intact human red cells. 1. When red cells that have been starved for about 6 hr are loaded with inorganic phosphate and incubated in high-sodium potassium-free media, the ouabain-sensitive efflux of potassium from the cells is accompanied by a ouabain-sensitive incorporation of inorganic phosphate into ATP.2. The magnitude of the incorporation varies roughly linearly with the concentration of sodium in the medium. The ratio (ouabain-sensitive potassium efflux)/(ouabain-sensitive ATP synthesis) is probably not much less than 2 nor much greater than 3.3. Potassium in the medium inhibits the ouabain-sensitive incorporation of phosphate. The concentration of potassium necessary for half-maximal inhibition is about the same as the concentration at which, under similar conditions, ouabain-sensitive potassium influx and the stimulation of ouabain-sensitive potassium efflux are both half-maximal.4. These observations suggest that the ouabain-sensitive efflux of potassium from red cells incubated in high-sodium potassium-free media is associated with a reversal of the entire pump cycle. In media containing sufficient potassium to saturate the pump, the efflux appears to involve the reversal of only part of the cycle.


The relation between body size and maximum and minimum metabolic rates in the new-born pig. 1. Measurements of rates of oxygen consumption were made on a total of sixty-two Large White pigs aged between 1 hr and 6 days, with a range of body weight from 0.75 to 2.40 kg.2. The maximum rate was determined from the continuous estimation of oxygen consumption as the environmental temperature fell past the point at which the maximum occurred.3. The minimum rate was determined both as the environmental temperature rose through the zone of thermal neutrality, and from measurements at thermal neutrality.4. In animals aged 1-6 days the mean maximum rate was 49.0 ml. O(2)/kg.min, and the mean minimum was 15.3 ml. O(2)/kg.min. Both rates were proportional to body weight and not to surface area.5. Pigs less than 1 day old exhibited lower maximum and minimum rates than the older pigs.


Perfusion from cerebral ventricle to cisterna magna in the unanaesthetized cat. Effect of calcium on body temperature. 1. A method is described for the perfusion of the liquor space from a lateral cerebral ventricle to the cisterna magna in the unanaesthetized cat. Perfusions were carried out for 30-40 min using various physiological salt solutions whilst rectal temperature was recorded.2. When the salt solution used contained calcium in the physiological concentration, rectal temperature remained unchanged, but when it contained no calcium an intense hyperthermia developed during the perfusion. The finding that calcium must be present in the perfusion fluid for preventing temperature from rising may lead to a new understanding of the working of the ;set-point' in the control of body temperature and of the mechanism of action of pyrogens.3. Independent of the nature of the perfusion fluid a long-lasting late rise in temperature developed after a perfusion. This happened regularly when the infusion needle was inserted only into the hub of the ventricular cannula, but rarely when the needle was extended beyond the tip of the cannula shaft and the cannula had been flushed out during the preceding days. It is therefore thought that an unknown pyrogenic factor present in the lumen of the cannula and washed into the ventricle with the perfusion fluid is responsible for this effect.4. The effluent collected from the cisterna contracted the fundus strip of the rat stomach. As the contractions were little affected by BOL, they are attributed mainly to an action of prostaglandin E(1) and not to an action of 5-HT. There was no difference in the biological activity of the effluent whether the perfusion fluid contained calcium or not.


The effect of adrenaline on the contraction of human muscle. 1. Infusions of adrenaline in physiological amounts alter human muscle contractions evoked by nerve stimulation.2. Adrenaline shortens the duration of the slow calf muscle twitch, but has no effect on the fast twitch of adductor pollicis.3. Adrenaline decreases unfused tetanic tension and increases the oscillation of tension in 10/sec tetani of calf muscle and adductor pollicis. The usual rise of tension and decrease in oscillation in unfused tetani (;ramp' phenomenon) is abolished.4. Adrenaline has no effect on maximal tetanic tension or maximal rate of rise of tension in a fused tetanus of adductor pollicis.5. The effects of adrenaline on human muscle are due to stimulation of beta-adrenotropic receptors, for they are abolished by the beta-adrenotropic antagonist DL-propranolol (but not by D-propranolol), and are mimicked by isoprenaline but not by noradrenaline.6. The effect of adrenaline on adductor pollicis is abolished by local beta-blockade of one arm with intra-arterial DL-propranolol, indicating that the responsible beta-receptors lie peripherally.7. The changes in muscle contraction observed cannot be explained by altered muscle temperature, for this falls during adrenaline infusion; nor are they due to an action on neuromuscular transmission, for these small doses of adrenaline do not affect the muscle action potential. The evidence points to a direct action of adrenaline on muscle.


The attenuation of rod signals by bleachings. 1. Contrast flash technique allows the rod threshold to be measured even when it lies far above the cone threshold. In this way the rod dark adaptation curve after rhodopsin bleaching can be measured over 6 log units.2. By retinal densitometry the regeneration of rhodopsin can be measured in the same subject. It is found that the log threshold is raised 1.2 units for each 10% of rhodopsin in the bleached state.3. We have tried to discover whether bleaching raises the threshold by desensitizing the rods, or (like backgrounds) by attenuating their signals. Neither suggestion satisfies all conditions.4. All are satisfied by [Formula: see text], where N is the size of rod signal, constant for threshold; theta, theta(D) are steady backgrounds of light and receptor noise; varphi is the threshold flash with sigma a constant of about 2.5 log td sec; B the fraction of pigment in the bleached state.


Signals from cones.

Signals from cones. 1. We have studied red and green cones by contrast flash inhibition and found them both to be very similar to rods in their response to flash energy, except that all light quantities must be some 100-fold greater in cones for the same effect.2. Using the methods of a previous paper (A.R.T. a) where no backgrounds were employed, we plotted log test flash lambda against log surround flash varphi with criterion that lambda should just be detected. The experiment was repeated with a ;windmill stop' interposed in the varphi flash which reduced its area symmetrically to (1/8). From these two curves it is possible to extract the relation between N, the inhibitory signal, and varphi, the test flash. It isN = varphi/(varphi+sigma),where sigma, the semi-saturation constant, is about 4.5 log td sec.3. Using the methods of (A.R.T. b) where backgrounds were studied, we measured the increment threshold for the surround flash varphi against its background theta using as criterion not that varphi should just be seen but that it should generate a fixed inhibitory signal N so that the fixed test flash lambda could just be seen.4. This increment threshold curve resembled the Aguilar & Stiles (1954) curve for rods, showed saturation and a complete symmetry about the 45 degrees line through the point with co-ordinates (log theta(D), log sigma).5. These results imply that the cone signal N is related to flash varphi and steady background theta by [Formula: see text], where theta(D) is receptor noise (= eigengrau), and varphi and theta are expressed in units of quantum catch.6. The ordinary increment threshold for cones does not show saturation because a steady saturating background bleaches all the pigment away. When the background is presented for only 100 msec with dark pauses between, no great bleaching occurs and saturation is seen.


An electrophysiological investigation of the slow fibre system in the frog rectus abdominis muscle. 1. Junctional potentials were recorded with a micro-electrode inserted into muscle fibres of the rectus abdominis muscle of the frog. Large and small nerve fibres were stimulated separately, using a selective stimulation technique. In a few muscle fibres rectangular current pulses were applied through a second micro-electrode to examine current-voltage relations.2. Two groups of muscle fibres could be distinguished: (a) Muscle fibres with resting potentials less negative than -75 mV, being localized at the ventral surface only and representing about 9% of the superficial fibres. These fibres were found to be innervated by small (high-threshold) nerve fibres and responded to single indirect stimuli with a typical s.j.p. (long latency, multiple components, after-hyperpolarization); upon repetitive stimulation summation of s.j.p.s and a slowly increasing tension could be recorded. The fibres showed a slow time course of electrotonic potentials, relatively high membrane resistance and ;delayed rectification'. (b) Muscle fibres with generally much higher resting potentials, being innervated by large (low-threshold) nerve fibres only. Upon indirect stimulation a short-latency end-plate or action potential (followed by a twitch) was recorded. The membrane time constant and input resistance of these fibres were similar to those of twitch fibres in other frog muscles.3. No evidence was found in the present work for the existence of an intermediate type of muscle fibre.4. It is concluded that the rectus muscle, similar to other frog muscles, contains two distinct types of muscle fibres, twitch and slow.