Wiley
0033-5541
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TYPES OF VISUAL RESPONSE FROM SINGLE UNITS IN THE OPTIC TECTUM AND OPTIC NERVE OF THE GOLDFISH Using metal‐filled micropipette electrodes we have recorded responses from single units in the optic tectum and optic chiasma of the goldfish. Responses were evoked by visual stimulation with spots of light and with black discs of various sizes. In many cases, after recording from a unit, the position of the electrode tip was marked by making an electrolytic lesion 10‐50 µ in diameter. These lesions were all found to be in one of the fibre layers of the tectum, either in one of the three most superficial fibre layers which contain the optic afferent fibres, or in the deepest layer of fibres. The two most superficial fibre layers contained “on”, “off” and brief “on‐off” units whch did not appear to be segregated into strata containing only one type of unit. Some of these units were directionally sensitive. Slowly‐adapting “on” and “off” units predominated in the third fibre layer. The deepest fibre layer, below the main layer of tectal cells, contained all the types of units found in the fibre layers near the surface of the tectum. All the types of response found in the optic tectum were also recorded from the optic chiasma. Maps were made of the receptive fields of units recorded in the optic chiasma and at various depths in the optic tectum. Receptive fields organized into adjacent, rather than concentric “on” and “off” zones, were frequently found in the optic chiasma and at all levels in the tectum. The topographical projection of the visual field onto the optic tectum was mapped. Units encountered during an electrode penetration into the tectum normal to its surface were found to have overlapping receptive fields. No ipsilateral projection was found.
Tập 49 Số 2 - Trang 199-209 - 1964
VAGAL DEFLATION AND INFLATION REFLEXES MEDIATED BY LUNG IRRITANT RECEPTORS Lung irritant receptors in anaesthetized rabbits are stimulated by deflations and large inflations of the lungs, with irregular and rather rapidly adapting discharges. After deflation the spontaneous discharge of the receptors is increased, and dynamic compliance is decreased. After inflation the spontaneous discharge is decreased, and compliance is increased. The responses of the receptors to inflation and deflation and the relationship with compliance suggest that they are part of the vagal reflex mechanism stimulating breathing or inspiratory activity in these conditions.
Tập 55 Số 2 - Trang 153-163 - 1970
<i>IN VIVO</i> SURVIVAL IN THE HUMAN SUBJECT OF TRANSFUSED ERYTHROCYTES AFTER STORAGE IN VARIOUS PRESERVATIVE SOLUTIONS The results of the commonly accepted in vitro tests, made upon samples of stored blood, are fallacious indicators of the state of preservation of biological activity, as judged by the subsequent in vivo survival of the erythrocytes. In the selection of preservative solutions, however, in vitro tests may have a negative value. For instance, if blood hæmolyses rapidly in a given solution, that solution may safely be rejected. If, however, a solution is found to be successful in inhibiting hæmolysis, it will not necessarily succeed in prolonging in vivo survival. The degree to which stored erythrocytes resist vigorous shaking in the presence of glass beads is not correlated with their survival time in vivo . Although the osmotic fragility of stored erythrocytes, as usually measured, has led to many fallacious conclusions as to the value of different blood preservatives, a revised test in which the erythrocytes are first treated with fresh plasma may be found more useful. The in vivo survival of blood stored without carbohydrate is almost as good as that of fresh blood when the period of storage is 6 days or less. I. H. T., sodium citrate, and heparin all seem to have a similar effect upon subsequent survival; defibrinated blood seems to survive slightly better. In the treatment of anæmia it is suggested that the limit of 6 days is not exceeded when using blood stored in one of these solutions. Blood stored for 14 days without carbohydrate is almost useless to the recipient as a source of biologically active erythrocytes, although it usually does not contain sufficient free hæmoglobin at this time to be actually a source of danger. Dextrin and sucrose, although they delay the onset of hæmolysis in vitro almost as well as glucose, have very little effect in prolonging the in vivo survival of blood. The effect of glucose in prolonging the survival of erythrocytes is very definite, and varies with alterations in the amount and concentration of glucose that is added. When approximately one volume of citrate‐glucose solution is added to four volumes of blood, variation of the concentration of glucose in the final mixture from 0·6 to 2·2 per cent, makes little difference to subsequent survival. If a larger volume of citrate‐glucose solution is added, however, and a final concentration of 2·7 per cent. in the final mixture is attained, survival is very definitely prolonged. Thus, whereas blood stored in the standard citrate‐glucose solution (VI) for periods of 11‐15 days already shows some falling off in survival, blood stored with the Rous‐Turner solution (X) for periods up to 21 days has a survival which is very little inferior to that of fresh blood. Although the Rous‐Turner solution is thus a better preservative than the citrate‐glucose solution in general use, the advantage is not obvious with blood stored for less than 10 days at least. Moreover, the large relative volume of diluent in the Rous‐Turner solution is a definite disadvantage both from the administrative and transfusion points of view. Thus for blood banks in which the turnover of blood is completed in 10 days or less there is no advantage in changing to the Rous‐Turner solution. Further, the use of a small volume standard citrate‐glucose solution leads to the production of plasma with a relatively high protein content, and this is important when blood that is not required for transfusion is to be used for plasma production. It may be emphasised that of the very many solutions that have been recommended for the preservation of blood, almost all up to now have been selected on the basis of in vitro tests. Such solutions are accordingly only by chance the best for preserving the biological value of stored erythrocytes. In the selection of new preservative solutions, and particularly in devising new citrate‐glucose mixtures, it is recommended that the effect of the solutions upon the survival of the erythrocytes after transfusion be used as the main criterion of value, in preference to the commonly accepted in vitro tests. We should like to thank Dr. J. F. Loutit for permission to carry out this work; Dr. M. Maizels for helpful criticisms; Dr. G. L. Taylor of the Galton Laboratories Serum Unit, for very kindly supplying M and N test sera once more, and Dr. L. F. Hewitt for carrying out the pH determination.
Tập 31 Số 4 - Trang 359-392 - 1942
THE ANTIDIURETIC ACTION OF MORPHINE: ITS SITE AND MODE OF ACTION IN THE HYPOTHALAMUS OF THE DOG 1. Observations made on dogs show that morphine sulphate administered during the course of a water diuresis is antidiuretic, whether it is given intravenously (0·08 mg./ kg.) to the unanæsthetized animal, or injected into the supraoptic nuclei (4‐32 ug.) under chloralose ancesthesia. 2. After section of the supraoptic tracts the injection of morphine sulphate intravenously into the unanæsthetized dog does not cause antidiuresis. 3. The release of adrenaline from the suprarenal medulla is not a factor in the antidiuretic action of morphine. 4. In unanæsthetized dogs into whose supraoptic nuclei DFP has previously been injected, the intravenous administration of morphine sulphate consistently causes an inhibition of the rate of urine flow. 5. Acute tolerance of the antidiuretic response to morphine is not seen on giving two or three small doses in the course of a few hours. 6. Consideration of the results leads to the conclusion that morphine induces antidiuresis by a direct effect on the supraoptic cells, causing the release of the antidiuretic hormone of the posterior lobe of the pituitary. This effect of morphine is unrelated to cholinesterase.
Tập 36 Số 3 - Trang 149-158 - 1951
THE INFLUENCE OF CORTISONE ON CELL DIVISION 1. The influence of large doses of cortisone on the mitotic activity which normally occurs after partial hepatectomy in mice was studied. At the same time the changes in liver protein, fat, glycogen and nucleic acids were followed. 2. In the mice given cortisone, mitoses were rarely seen 2 days after operation, whereas at that time the mitotic rate in controls was very high. Later, at 6 days, this difference was not observed. 3. Although the increase in weight of the liver after partial hepatectomy was the same in experimental and control mice, in the former this was largely due to a deposition of fat and glycogen. There was, however, some new formation of protein in cortisone‐treated mice. 4. RNA regeneration was nearly normal; DNA, however, failed to regenerate in mice given cortisone. 5. Cell division occurring normally in the endothelium of the crypts of Lieberkühn was not inhibited by cortisone in large doses. 6. Mitoses were seen in lymphoid follicles in mice receiving large doses of cortisone. 7. The conclusion that cortisone does not inhibit mitoses in every tissue is discussed.
Tập 37 Số 4 - Trang 239-257 - 1952
A HISTOLOGICAL STUDY OF THE ORGANIZATION OF THE RUMEN EPITHELIUM OF SHEEP 1. The papillæ of the surface of the rumen of sheep have been shown to have a rich blood and lymphatic supply in intimate contact with the basal layer of the stratified squamous epithelium. 2. The basal layer of the epithelium consists of columnar cells which in the papillary bodies are arranged round the capillaries, the long axis of the cells being perpendicular to the length of the capillaries. Cells similar to “prickle” cells of the skin are present in the transitional layer between the basal columnar cells and the outer keratinized layers. 3. Mitochondria, which have been shown to be very numerous in the columnar cells, are often elongated and orientated in the long axis of the cells. 4. An analogy between the cubical epithelium of the convoluted tubules of the kidney and the columnar cells of the rumen epithelium is suggested.
Tập 41 Số 3 - Trang 247-253 - 1956
RE‐EVALUATION OF RESPIRATORY REFLEXES In cats anæsthetized with chloralose it was found that below about 18° C. the rhythmic pattern of discharge in low‐threshold pulmonary stretch fibres is reversed in relation to the respiratory cycle. This reversed pattern is apparently responsible for the reversal of the Hering Breuer inflation reflex (Head's paradoxical reflex). Evidence favouring this is that reflex inhibition of respiration, produced by high frequency electrical stimulation of pulmonary stretch fibres applied against a background of low frequency stimulation, is converted to excitation between 9 and 11° C. Head's paradoxical reflex appears when the total discharge in low‐ and higher‐threshold pulmonary fibres during inflation becomes less than the total discharge in the former before inflation. A nomogram showing the relation between temperature and the peak frequency of a train of impulses in fibres of different conduction velocities is presented. The likely mechanism responsible for the quantitative variation of the inflation reflex (and its reversal) with temperature is given.
Tập 51 Số 2 - Trang 151-163 - 1966
THE INFLUENCE OF THE VAGUS ON THE SECRETION OF MUCUS THE STOMACH 1. Evidence is produced that the vagus controls the secretion of the cardiac and pyloric mucous glands and the mucous neck cells of the fundal glands. 2. A histological procedure is described for staining these cells selectively and intensely. 3. No effect of vagal nerve stimulation on the surface epithelial cells of the stomach has been seen. 4. Innervated pyloric pouches cease to secrete on starvation, but secrete at once following the ingestion of food. 5. Blood transfusion has been found greatly to improve the general condition of the decapitate cat after a long and complicated preparation.
Tập 30 Số 4 - Trang 329-339 - 1941
RESPIRATORY CHANGES INDUCED BY THE IMMEDIATE BLOCK OF NERVOUS CONDUCTION IN THE VAGUS NERVES A differentiation of vagal respiratory reflexes has been obtained in rabbits by the application of a D.C. current of various intensities to both the vagus nerves. It has been possible to abolish the inflation reflex while Head's paradoxical response to inflation was revealed without eliminating the deflation reflex. The coexistence of Head's paradoxical reflex and the deflation reflex may suggest that these reflex responses originate through activation of the same receptors. The inspiration which follows the immediate withdrawal of vagal afferent inflow has a much longer duration than the following ones: this seems to suggest that some of the inhibitory influence coming through the vagus is taken over, after the duration of the first breath, by some other inhibitory mechanism. A vagal ‘block’ introduced at the same time as an occlusion of the airways leads to an inspiratory effort which is much longer than when occlusion only is performed. This could be ascribed to the blockade of some vagal fibres normally active at FRC which should have an overall inhibitory influence on inspiratory activity.
Tập 57 Số 2 - Trang 207-212 - 1972
SOME EFFECTS OF ŒSTRADIOL BENZOATE ON IRON METABOLISM IN THE IMMATURE PULLET The injection of œstradiol benzoate (18 mg. in six 48‐hourly doses) into pullets 12–14 weeks old caused a fall in blood hæmoglobin and a large rise in plasma iron. A possible slight increase in non‐hæm iron in the liver was also noted.
Tập 41 Số 3 - Trang 271-274 - 1956