摘要:

SummaryThe ultrastructureof extensor dtgitorum logus(EDL) andsoleusmuscles from two groups of Wistar rats obtained from different colonies has been examined both qualitatively and morphometrically. Compared tosoleus. EDL fibres are richer in sarco‐plasmic reticulum, but contain fewer mitochondria, lipid droplets and nuclei. The quantities of these organelles and related surface volume ratios in single morphometric samples varied, reflecting the heterogeneity of fibre ultrastructure within the muscles. There were significant differences in many features quantified between the two groups of rats; these differences present a problem in comparing different published reports but, fortunately, the EDL/soleusratios were similar in both groups. Within each group, the fibre fractions occupied by mitochondria and sarcoplasmic reticulum found in the morphometric samples were reciprocally related. The different amounts of sarcoplasmic reticulum in the two muscles is insufficient to explain the different calcium pumping capacities observed by Briggs, Poland and Solaro (1977), suggesting a control at the level of the pump protein synthesis.

ISSN:0004-945X    

DOI:10.1038/icb.1980.22

出版商:Nature Publishing Group    

年代:1980

数据来源: WILEY

摘要:

SummaryAfter oral administration of infective third stage larvae (L3) ofNematospiroides dubiusto young mice, intestinal worms persist for many weeks. However, in mice injected parenterally withN. dubiusadult worms, the intraluminal intestinal infection arising after L3 administration can be terminated within 3 to 4 weeks. This accelerated rejection is seen in sensitized BALB/c mice (and (CBA/H × BALB/c)F1mice) and in particular females, but has not been demonstrated in sensitized CBA/H mice. In female BALB/c mice, small numbers of living worms are more effective at sensitization than dead worms, intraperitoneal and subcutaneous implantations are both effective, and products from adult worms incubatedin vitro(i.e. ‘excretory/secretory’ (ES) products) will sensitize but only with very high doses in adjuvant. Using appropriate isolated antigen preparations, comparative immunoparasitological analyses in different mice should provide clues on the nature of host‐protective immunities against intestinal nematode infections which are potentially chronic. From the present studies, two groups which differ most dramatically in the consequences of adult worm sensitization are young male CBA/H versus older female BALB/c mice.

ISSN:0004-945X    

DOI:10.1038/icb.1980.23

出版商:Nature Publishing Group    

年代:1980

数据来源: WILEY

摘要:

SummaryRoutine histological and indirect immunofluorescence techniques were used to examine the histological details of changes in the distribution of epidermal growth factor (EGF) in the submandibular salivary glands of mice during secretion. Comparisons were made between glands of normal mice and those of mice given one of a number of secretagogues at various times prior to sampling. Normal submandibular salivary glands in male mice had an extensive system of convoluted granular tubules (CGT), the cells of which contained EGF. When adrenaline or α‐phenylephrine was administered, the CGT cells degranulated, and there was a concomitant loss of intracellular EGF‐positive immunofluorescence. The excretory ducts were engorged with immunofluorescent material, indicating secretion of EGF into saliva, while the ductal cells themselves remained EGF‐negative. The degranulation response could be blocked by phentolamine, but not by propranolol, and no changes in EGF distribution followed the administration of pilocarpine. It was concluded that EGF is secreted, at least partly into the saliva, following an α‐adrenergic response, and that this occurs with degranulation of the cells of the CGT.

ISSN:0004-945X    

DOI:10.1038/icb.1980.24

出版商:Nature Publishing Group    

年代:1980

数据来源: WILEY

摘要:

SummaryUtilizing the techniques of radioallergosorbent test (RAST), inhibition of RAST and isoelectric focusing on polyacrylamide gels, antigenic cross‐reactivity has been shown between extracts ofAscaris lumbricoides, Ascaris suumandNecator americanus(hookworm). Antigenic homology is extensive between the two Ascaris preparations. The antigens common to hookworm and Ascaris, while representing a minor component of Ascaris body fluid, are nonetheless potent Stimulators of IgE antibody production in subjects infected only with hookworm larvae. These shared antigens appear to have a pI of less than 5.1. The hookworm specific antigens also have a pI of less than 5.1, whereas those specific to Ascaris have pI values in the ranges of 5.0 to 6.0 and 7.0 to 8.6. These latter antigens, i.e. those with pI between 7.0 and 8.6, apparently elicit an immune response only during an active infection with Ascaris.

ISSN:0004-945X    

DOI:10.1038/icb.1980.25

出版商:Nature Publishing Group    

年代:1980

数据来源: WILEY

摘要:

SummaryThe physicochemical and immunochemical characteristics of the allergens fromDermatophagoides pteroyssinushave been described, in particular those for the allergens designated Dpt 4 and Dpt 12. Dpt 4 is a high molecular weight allergen with an apparent molecular weight of 274,000 daltons and a pI of 4.5. In contrast, the antigenically unrelated Dpt 12 has an apparent molecular weight of 24,000 daltons and a pI 6.6. Both allergens demonstrate heterogeneity, either in molecular weight or pI. Dpt 12 appears to be the major allergen in extracts ofD. pteronyssinusand probably corresponds to the low molecular weight allergen previously described by other workers.

ISSN:0004-945X    

DOI:10.1038/icb.1980.26

出版商:Nature Publishing Group    

年代:1980

数据来源: WILEY

摘要:

SummaryHigh molecular weight allergens which react with the S107 murine IgA myeloma and with the lectins Concanavalin A (Con‐A) and tridacnin have been identified and characterized in extracts of the miteDermatophagoides pteronyssinus. Mite extracts from two different manufacturers were Fractionated by Con‐A affinity chromatography. The major antigen in both the Con‐A bound and unbound fractions, which was antigenically indistinguishable, reacted with tridacnin and the S107 myeloma. This high molecular weight, multi‐reactive antigen corresponded to allergen Dpt 4, suggesting that Dpt 4 exists as isoallergens, each differing in the degree of glycosylation or in the type of carbohydrate moiety comprising the glycan part of the allergen. Mite media extracts also reacted with Con‐A, tridacnin and the S107 myeloma but were not allergenicper se.

ISSN:0004-945X    

DOI:10.1038/icb.1980.27

出版商:Nature Publishing Group    

年代:1980

数据来源: WILEY

摘要:

SummaryWhen the bursa of Fabricius was isolated from environmental stimuli across the bursal epielium by clipping the bursal duct on the 19th day of incubation, marked retardation was observed both in the bursal development and in the maturation of the immune reactivity. Neither necrotic changes nor involution in the bursa was, however, observed at any stage examined after clipping the bursal duct. Lymphopoiesis in the bursa and the immune reactivity of these chickens gradually increased with age, although they were constantly lower than those of controls. These results suggest that environmental stimuli across the bursal epithelium play an important role in the amplification mechanisms for B‐cell differentiation in the bursa.

ISSN:0004-945X    

DOI:10.1038/icb.1980.28

出版商:Nature Publishing Group    

年代:1980

数据来源: WILEY

摘要:

SummaryThis paper describes an experiment which provides information on the ontogeny of some parameters of the intestinal immune system in normal lambs. It is also demonstrated that oral administration of a gram negative bacterial vaccine to foetal lambs resulted in non‐specific amplification of the population of IgA plasma cells in the gut and its associated lmphoid tissue, suggesting involvement of bacterial lipopolysaccharide, a recognised B‐lymphocyte mitogen, in ontogeny of gut immunity.

ISSN:0004-945X    

DOI:10.1038/icb.1980.29

出版商:Nature Publishing Group    

年代:1980

数据来源: WILEY

摘要:

Summary5‐Methylcytosine content of chick embryo DNA was almost constant, independent of the age of embryos. Labelling experiments with isolated nuclei revealed that 5‐methylcytosine was only the methylated product and the rate of DNA methylation in nuclei decreased with the age of embryos. The enzyme activity of nuclear extract paralleled the decrease. DNA from the 4 and 10‐day embryos were methylated at the same rate by solubilized DNA methylase, indicating that the degree of DNA methylation does not vary with the age of embryos.

ISSN:0004-945X    

DOI:10.1038/icb.1980.30

出版商:Nature Publishing Group    

年代:1980

数据来源: WILEY

摘要:

SummaryThe infectivity, pathogenicity and immunogenicity of 5 human, 6 calf, 2 pig and 2 foal rotavirus isolates were studied in gnotobiotic calves, piglets and lambs. Three of the human isolates produced subclinical infection in newborn gnotobiotic piglets and the piglets developed neutralising antirotavirus antibody. When challenged with pig rotavirus 2 weeks later, the piglets did not develop diarrhoea, but rotavirus was detected in the faeces. In contrast, piglets inoculated with the other 2 human isolates failed to show evidence of infection and there was no specific antibody detected. These piglets developed diarrhoea when challenged 2 weeks later with pig rotavirus. The 4 human isolates failed to infect gnotobiotic calves and lambs.Two foal rotavirus isolates produced subclinical infection in piglets, but the subsequent protection against a challenge with pig rotavirus lasted less than 15 days. The foal rotavirus isolates failed to infect gnotobiotic calves and lambs.Two of the calf rotavirus isolates were extremely pathogenic to newborn pigs. Two other calf isolates infected newborn lambs, one of which developed mild diarrhoea.Of the 2 pig rotavirus isolates one induced a subclinical infection in newborn lambs but neither infected calves.These experiments suggest that cross‐infection between species is not a property shared by all rotaviruses.

ISSN:0004-945X    

DOI:10.1038/icb.1980.31

出版商:Nature Publishing Group    

年代:1980

数据来源: WILEY