摘要:

SUMMARYBy means of double‐barrelled microelectrodes filled with appropriate salt solutions we have observed the effects of injecting, iontophoretically, sodium, potassium and chloride ions into muscle fibres of the rabbit right ventricle.Injection of sodium ions produced a reversible decline in maximum rate of depolarisation and amplitude of the action potential with no change in shape or voltage‐time course of the action potential.Injection at equivalent rates of equivalent amounts of potassium or chloride ions had no effect.The changes observed after sodium injection are in agreement with the prediction of the mathematical model of the cardiac action potential described by George and Johnson (1962).

ISSN:0004-945X    

DOI:10.1038/icb.1962.11

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYThe magnitude of the resting polarisation resistance and the magnitude and time course of the changes in the polarisation resistance have been measured during the action potential in ventricular muscle from the cat, dog, sheep, rat and guinea pig. The theoretical time course of the changes in membrane conductivity and in membrane permeability have been computed.

ISSN:0004-945X    

DOI:10.1038/icb.1962.12

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYNormal untreated chickens, between one week and about four months of age, have a coating of globulins on their red cells detectable by the antiglobulin reaction.Indirect Coombs tests have shown that the serum of fowls older than two weeks contains the factor responsible for this coating.The specificity of the reaction has been discussed, and evidence presented that only a small fraction of serum globulins are responsible.

ISSN:0004-945X    

DOI:10.1038/icb.1962.13

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYHepatic lymph was collected in hypercholesterolaemic rabbits and the lymph : plasma ratios of albumin and of the three classes of lipoproteins separated by ultracentrifugation at densities of 1·019, 1·063 and 1·200 were determined.These ratios were: 91·6 for albumin; 69·2 for lipoprotein of density 1·063–1·200; 43·4 for 43·4 forlipoprotein of density 1·019–1·063 and 32·8 for those lipoproteins of density less than 1·019, giving a gradient which appeared to be related to the size of the macromolecule over a wide range from 35 to 700 Å.These results were broadly similar to those obtained in another system of highly permeable capillaries in the injured paw. The significance of these findings in regard to the fine structure of the hepatic sinusoids has been discussed.

ISSN:0004-945X    

DOI:10.1038/icb.1962.14

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYThe albumin of liver lymph may derive entirely from the plasma or newly metabolized protein may be added directly to lymph by the liver cells. Following the injection of T‐1824 and131I‐albumin the disappearance of label from plasma and its appearance in liver lymph was studied. When specific activity curves were compared with similar curves for liver following injection of131I‐γ‐globulin, and for leg following131I‐albumin it was apparent that only minor amounts, if any, of new protein could be reaching the liver lymph directly from the synthesizing cells.

ISSN:0004-945X    

DOI:10.1038/icb.1962.15

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYThe isolated auricle of the lizardTiliqua rugosaresponds by positive inotropic and chronotropic effects to a number of drugs including catechol amines, tyramine, dichlorisoproterenol, histamine, serotonin, bretylium, ganglion blocking agents, atropine, and, in the presence of atropine, to ganglion stimulants and vagus nerve stimulation. Evidence is presented that the sympathomimetic effects of vagus stimulation are due to the presence of sympathetic nerves and that the mechanisms of parasympathetic and sympathetic transmission are similar to those of the mammal. The actions of tyramine, diphenylmethylpiperazinium iodide, cocaine and bretylium are described.

ISSN:0004-945X    

DOI:10.1038/icb.1962.16

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYInjection of stilboestrol, either alone or in conjunction with progesterone, into 13 bitches was in all cases followed after between 3 and 14 months by the development of ovarian tumours. One of these was a dysplasia and 12 were definite neoplasms as shown by invasion and development (in 9 cases) of metastases. Administration of progesterone in addition to stilboestrol did not influence the macroscopic or microscopic appearances of the neoplasms nor their behaviour. The neoplasms developed independently of the breed and age of the dogs. The average latent period was reduced considerably by injection of larger oestrogen doses.Hormonal withdrawal from five dogs bearing ovarian neoplasms was followed, between 10½ and 14½ months later, by regression of the tumours and fibrosis and calcification of the secondary growths.The high tumour yield and their hormone dependence indicates a specific activity of the injected material, either the stilboestrol itself or a metabolite.

ISSN:0004-945X    

DOI:10.1038/icb.1962.17

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARY59Fe which entered reticulocytesin vitroor was incorporated into developing red cellsin vivocould be separated into fractions by a chemical procedure or by centrifugation of red cell haemolysates. The chemical separation depended on the solubility of the iron compounds in acid and in alkaline solutions and usually the ratio of the amounts of iron in the acid and alkaline extracts was 30 to 70. The addition of 10−3M KCN to reticulocytes before addition of59Fe changed this ratio to 85 to 15. Particulate matter separated from red cell haemolysates by centrifugation at 6,000 g. for 15 minutes also contained59Fe. When the59Fe was incorporated in vitro 28 p.c. was found in the stromal fraction and when 10−3M KCN was used 90 p.c. was found in the stromal fraction. With in vivo incorporation the stromal fraction contained 19 p.c. of the59Fe.The proportions of59Fe extracted with acid or associated with the stroma were not related to the age of the reticulocytes and did not move to the other fractions on further incubation with iron. There is some evidence to suggest that the iron in the acid extract was that present in the stromal fraction but this has not been proved. However, the iron in all fractions must be principally haemoglobin iron obtained from functional haemoglobin. The separations achieved by the chemical and physical methods suggest that there are different forms of haemoglobin present in red cells which are capable of transporting oxygen.

ISSN:0004-945X    

DOI:10.1038/icb.1962.18

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYThe effect of intravenous and intra‐arterial adrenaline Infusions on the circulation in skin and muscle of the human forearm has been followed by the technique of superficial and deep venous blood oximetry. Forearm blood flow was measured by venous occlusion plethysmography.The initial transient increase in forearm blood flow seen on both intravenous and intra‐arterial infusion of adrenaline was associated with an abrupt increase in deep blood oxygen saturation indicating an increase in muscle blood flow and the subsequent sustained increase in forearm blood flow during intravenous infusion was also accompanied by an increased muscle blood oxygen saturation. Similar increases were seen during intra‐arterial infusion of 0·05 and 0·1 μg./min., a dose of 0·2 μg./min. intra‐arterially also increased the muscle blood flow although the total forearm flow was reduced, while larger doses (0·5 μg./min.) caused a fall in both muscle flow and total forearm flow.The “after‐dilatation”, only seen following intra‐arterial infusions, was more marked with the larger doses and is attributed to the wearing off of a transient constrictor effect on the muscle vessels. Superficial blood oxygen saturation was reduced by most doses of adrenaline indicating a decrease in skin blood flow. The findings indicate that the dilator action of adrenaline on muscle vessels has a longer duration than the constrictor action.

ISSN:0004-945X    

DOI:10.1038/icb.1962.19

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY