摘要:

SUMMARYTen ewes were fed for nine months on a cobalt‐deficient ration of wheaten hay chaff and gluten. Four of the animals were given cobalt throughout the whole period. The remaining six animals were given cobalt for the last two months only. Three of the ewes in the + cobalt group were pair fed with three in the ‐ cobalt group.Biopsy samples of liver were taken at the beginning and end of the nine months period and at three intermediate times. Vitamin B12was measured in the liver samples by theL. leichmanniiassay method. Pantothenic acid was measured by means of microbiological assays withL. plantarumandL. casei. Total pantothenic acid, which was taken as a measure of coenzyme A, was measured after splitting its bound forms with alkaline phosphatase and a pigeon liver enzyme preparation. Free pantothenic acid, measured in half the liver plugs, averaged 2·5 p.c. of the total pantothenic acid (range 0·6–4·3 p.c.).Deprivation of cobalt led to a marked lowering of liver vitamin B12(from a mean value of 1·05 μg./gm. to a mean value of 0·12 μg./gm. in 6 months. The mean concentration rose to 0·48 μg./gm. two months after administration of cobalt.In six months of cobalt deprivation the pantothenic acid concentration in the livers of all the deficient sheep rose, the mean increase being 70 p.c. This change was reversible; two months after giving cobalt the pantothenic acid concentration had fallen again.Statistical analysis of the data for the pair‐fed sheep showed that there was a highly significant difference between the pantothenic acid concentrations in the livers of the sheep in the positive and negative groups, when the latter had been cobalt‐deficient for six months and seven months. The elevated pantothenic acid concentration was associated with a vitamin B12, concentration of about 0·1 μg./gm. of liver.There was no great or consistent difference between pantothenic acid measurements made by the two microbiological assay methods.

ISSN:0004-945X    

DOI:10.1038/icb.1963.1

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYSixty strains of 11 viruses were isolated from 25,901 mosquitoes of 32 species collected at Mitchell River Mission, Cairns and Normanton in 1960 and 1961. The viruses, the local prototype strains and the mosquito species, geographical location and year of repeatable isolations, were:Group A: Sindbis (MRM39) fromCulex annulirostrisandAedes normanensisat Mitchell River (1960) and Cairns (1961); AMM2021 (N544) fromAnopheles amictus amictusandCulex bitaeniorhynchusat Normanton (1961).Group B: Murray Valley encephalitis virus fromC. annulirostrisat Mitchell River (1960 and 1961); Kunjin (MRM16) fromC. annulirostrisat Mitchell River (1960); Kokobera (MRM32) fromC. annulirostrisat Mitchell River (1960 and 1961); Edge Hill (C281) fromAedes vigilaxandC. annulirostrisat Cairns (1961); Stratford (C338) fromAe. vigilaxat Cairns (1961).Koongol group: Koongol (MRM31) fromC. anulirostrisat Mitchell River (1960) and Normanton (1961); Wongal (MRM168) fromC. anulirostrisat Mitchell River (1960 and 1961).Ungrouped: MRM1 (found resistant to ether and sodium desoxycholate) fromC. anulirostrisat Mitchell River (1960); Mapputta (MRM186) fromAnopheles meraukensisat Mitchell River (1960) (not reisolated).C. annulirostriswas the commonest mosquito collected (12,124) and the source of 44 of the virus strains.Eight of the viruses appear to be new. One (Murray Valley encephalitis virus) has previously been isolated from man in Australia and two (Sindbis and AMM 2021) from mosquitoes elsewhere.

ISSN:0004-945X    

DOI:10.1038/icb.1963.2

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYMethods for the accurate assay of rabbit papilloma virus and its antibody are described. Viral infectivity is titrated by a technique in which up to fifty discrete tumours may be counted on a single inoculation site. Neutralizing antibody is measured with considerable accuracy by determining the dilution of serum producing a 50 p.c. reduction in tumour count. A complement fixation test designed to economize on reagents permits the quick and accurate titration of RPV antigen and antibody.Some of the relationships between tumours, infectious virus, antigen and antibody in naturally and experimentally infected rabbits are examined.

ISSN:0004-945X    

DOI:10.1038/icb.1963.3

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYIsologous subcutaneous spleen grafts attained a two to five times greater size in splenectomised hosts than in sham‐operated hosts. This size difference was greatest when donor spleens were from mice aged less than twenty‐four hours. Isologous thymus grafts grew equally well in splenectomised und sham‐operated mice. The percentage of lymphoid tissue and lymphocyte mitotic activity were higher in spleen grafts in splenectomised hosts than in grafts in control animals.No changes were observed in the host lymphoid tissues in any of the mice carrying spleen grafts.

ISSN:0004-945X    

DOI:10.1038/icb.1963.4

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYFrom a mouse virulent strain ofSalmonella typhimuriumC5 a leucine‐requiring mutant was obtained by ultra‐violet irradiation. The mutant was found to be relatively avirulent. On transduction of the mutant to prototrophy it still retained its avirulence therefore the leucine mutation appears to be unrelated to virulence.On the basis of the genetic investigations it was suspected that a single genetic difference existed between the two strains. A qualitative antigenic difference could not be demonstrated using serum bactericidal tests or by intravenous clearance of radioactive bacteria. However, a quantitative difference in some heat‐labile antigenic component was suggested by studying the survival characteristics of both the bacterial strains in the mouse peritoneum using suitably absorbed sera to preopsonise the bacteria.

ISSN:0004-945X    

DOI:10.1038/icb.1963.5

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYGroups of mice were painted with a solution of croton oil in acetone on one‐half of the skin of the back twenty‐four hours prior to an injection of urethane. The whole skin of the back was subsequently painted with croton oil weekly for twenty weeks. The number of papillomata developed on the skin was greater on the half given the preliminary application of croton oil. The augmented tumour yield is accounted for by local phenomena produced by the preliminary application of croton oil.

ISSN:0004-945X    

DOI:10.1038/icb.1963.6

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYAn agar‐gel immune haemolysis method was developed for detecting antibody in the lumen of tubular structures in tissue sections. It was used to show haemolytic antibody in renal tubules and blood‐vessels in immunized mice. Globulins and antibody were also found by gel‐diffusion precipitin and immunoelectrophoresis techniques in concentrates of urine from normal or from immunized mice.

ISSN:0004-945X    

DOI:10.1038/icb.1963.7

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYThe amount of adenosine deaminase activity in free‐floating lymphoid cells obtained from the efferent duct of the popliteal node of sheep has been shown to increase after the node was antigenically stimulated by chicken red cells. The increase in cellular enzyme content coincided with the appearance of plasma cells in the lymph and the presence of intra‐cellular antibody.The activity of the free enzyme was found to be higher in intermediate lymph than in peripheral lymph or blood plasma.

ISSN:0004-945X    

DOI:10.1038/icb.1963.8

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYA description is given of the location and general histology of the interstitial cells of Leydig in the testis ofTrichosurus vulpecula.Appropriate staining methods were employed to demonstrate the various cell contents. The reticular cytoplasm of the polygonal Leydig cells was crowded with numerous variously sized vacuoles. Many vacuoles contained masses of secretory material which also occurred as fine granules, aggregated into a semilunar arrangement, at the periphery of the vacuole. The round, pale‐staining nucleus frequently occupied an eccentric position in the interstitial cells.An abundant blood supply, taking its origin from the intertubular arteries which supplied the seminiferous tubules, was provided by arterioles and capillaries which vessels were evident between the groups and strands of Leydig cells.

ISSN:0004-945X    

DOI:10.1038/icb.1963.9

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

ISSN:0004-945X    

DOI:10.1038/icb.1963.58

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY