摘要:

Summary.1) Experiments with radio‐sodium (Na24) show that when an isolated frog skin separates two solutions containing NaCl (that on the inside being Ringer) the Na+‐flus from outside to inside is normally much higher than the outflux; this is true even when the outside NaCl concentration is only one millimole/l.2) The Na+‐influx (and thus the active sodium transport) shows a pronounced dependency on the pH of the inside solution. High pH values give high values for the Na+‐influx and vice versa.3) The pH of the outside solution has little effect on the Na+‐influx until pH is below‐ ca. 5. Then the 53+‐influs drops to a very low value, whereas the Cl–influx goes up.4) The Cl–influx is as a rule lower and often much lower than the simultaneous Na+‐influx. The variations in the Cl‐influx generally go parallel to the variations in Na+‐influx. There is also a pronounced parallelism between the potential difference across the skin and the influx of Na+‐ and Cl‐so that the more positive becomes the inside relative to the outside. the higher is the influx of Na + and Cl.5) When added on the inside of the skin adrenaline in the concentration 1/106brings about an enormous increase, in the outflux of Na+ and a considerable increase in the influx of this ion. Immediately after the addition of adrenaline a violent drop in the P.D. is observed. This drop and the further course of the P.D. curve depends on the outside salt concentration and the magnitude of the P.D. before the adrenaline addition. It is concluded that the initial drop in P.D. is due to an increased permeability to Na+. The secondary rise in P.D. shortly after the drop must be due to an increased Na+‐transport.6) Cyanide poisoning reduces the Na+‐influx to 5–25% of the original value. The outflux of ions is not reduced.7) The theoretical basis for the use of tracers to determine the active transport of an ion species through a membrane is considered. In the frog skin the Na+‐influx is as a rule a fairly good measure of the Na+actually transferredacrossthe skin. But the total transport work performed by the transporting cells is greater than indicated by the flus because, due to back diffusion, some Na‐ions may be subjected to transport more than once before leaving the skin.8) Based on the experiments a hypothesis is put forward which will account for the interdependency between the in‐ and outflux of Na+and Cl— and the potential difference across the skin.The radioactive isotopes used were kindly provided from the Institute of Theoretical Physics in Copenhagen. I wish to extent my gratitude to the head of this institute, Professor N. Bohr and to his staff, n

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1949.tb00550.x

出版商:Blackwell Publishing Ltd    

年代:1949

数据来源: WILEY

摘要:

Summary.The influence of the adrenocorticotropic hormone on the salt balance in axolotls has been studied.Injection of the hormone was found to increase the salt uptake through the skin of the animals.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1949.tb00551.x

出版商:Blackwell Publishing Ltd    

年代:1949

数据来源: WILEY

摘要:

Summary.1) Some practical and theoretical objections against the viscosimetric assay of hyaluronidase as generally employed have been advanced.2) A simplified method for the preparation of hyaluronate from vitreous humor, synovial fluid and umbilical cords has been worked out and some properties of the preparations determined.3) A method for the assay of hyaluronidase using viscosity measurements has been worked out based on the demonstration that the enzymatic depolymerisation follows a monomolecular reaction scheme. The reaction constant under specified conditions is used as a measure of hyaluronidase activity.4) The feasibility of defining an international unit of hyaluronidase based on measurement of the reaction constant is di

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1949.tb00552.x

出版商:Blackwell Publishing Ltd    

年代:1949

数据来源: WILEY

摘要:

Summary.Studies have been conducted on the possible growth factor requirements of twelve lactobacilli, several of them used in the microbiological amino acid analysis. Liver extracts and enzyme hydrolysates of casein were used as sources of growth factors. It was shown thatLactobacillus citrovorum(8081),Lactobacillus casein, Lactobacillus acidophilusandLactobacillus lactis100 required a strepogenin similar factor present in both types of materials. Besides, liver extracts containing the anti‐pernicious‐anemia factor were separated in three fractions all of which contained growth factors for these four microorganisms. The possible bearing of the results on the microbiological analysis of amino acids is emphasized. The possibility of using any of the four mentioned microorganisms for the standardization of the anti‐pernicious‐anemia factor is analyzed and discussed. Some of the properties of this factor are also discussed in the light of the results o

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1949.tb00553.x

出版商:Blackwell Publishing Ltd    

年代:1949

数据来源: WILEY

摘要:

Summary.The author has investigated the percentual Ci‐content of shells from chicken, duck, and goose eggs. The citric acid analyses have been carried out according to the method of Hunter and Leloir. The experimental material was composed of 30 chicken eggs, 6 duck eggs, and 6 goose eggs. The average Ci‐content in some‐what rounded figures of chicken eggs was found to be 1.5 mg. per g., of duck eggs 0.4 mg., and of goose eggs 0.3 mg., or expressed in p. p. m., 1,500, 400, and 300. A negative correlation seems to exist between the weight of the egg and the Ci‐content of the egg shell. The author stresses the practical importance of knowledge of the factors influencing the Ci‐content of

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1949.tb00554.x

出版商:Blackwell Publishing Ltd    

年代:1949

数据来源: WILEY

摘要:

Summary.1) The precision of the assay of pregnant mares' serum gonadotropin with the ovarian weight method is determined. With the material and method employed for the investigation presented, the limits of error of the assay are ± 15% or less (P = 0.05), when a number of 30 to 45 animals are used each for the standard and the unknown preparation.2) The susceptibility of the rats' ovary is variable. Therefore the potency of a preparation should be determined by simultaneously testing the standard and the unknown.3) A design for the assay is described. The design should be made with due regard to the level of precision re

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1949.tb00555.x

出版商:Blackwell Publishing Ltd    

年代:1949

数据来源: WILEY