ISSN:0004-945X    

DOI:10.1038/icb.1983.14

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryThe spontaneous interaction of sheep erythrocytes and human lymphocytes results in the formation of aggregates known as E‐rosettes. The antigen reactivity of murine T‐lymphocytes can be detected indirectly by the production of a lymphokine that augments the E‐rosette‐forming ability of human lymphocytes. An indirect E‐rosette augmentation (ERA) assay was used to study cellular reactivity and tumour‐related serum reactions in mice bearing methylcholanthrene (MCA)‐induced tumours. The assay was used to demonstrate the antigenic specificity of two tumours and to detect blocking factors in tumour‐bearer serum. Blocking factors were shown to be tumour‐specific and to act on lymphocytes at an early stage before exposure to antigen.

ISSN:0004-945X    

DOI:10.1038/icb.1983.15

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryThe cellular requirements for rejection of cultured islet allografts, a tissue expressing only class I alloantigens, have been studied. The results obtained show that sensitised Thy 1+, Lyt 2+lymphocytes and not Lyt 2−lymphocytes trigger acute graft rejection.

ISSN:0004-945X    

DOI:10.1038/icb.1983.16

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryNon‐specific hyporesponsiveness of cytotoxic T cells to alphaviruses and alloantigens was induced in male mice by multiple, large injections, starting at birth, of gamma‐inactivated alphavirus, stock‐grown in outbred mouse brains. Offspring of matings between 2 out of 17 treated males and normal females also exhibited significant non‐specific hyporesponsiveness (in comparison with normal control mice), without prior exposure to gamma‐inactivated alphavirus stock.

ISSN:0004-945X    

DOI:10.1038/icb.1983.17

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryThe properties of Leanyer virus, isolated in Northern Australia in 1974, were compared with those of Bunyamwera virus. Leanyer virus replicated in BHK‐21 and Vero cells. In sucrose gradients it had a density of 1·17 g/cm3and sedimented with the sameSvalue as Bunyamwera virus. The diameter of negatively stained virions was approximately 110 nm. Three species of RNA sedimenting at 30S (L), 26S (M) and 14S (S) and four virion proteins (L, G1, G2, N) were detected in preparations of purified virions. The results were consistent with the classification of Leanyer virus as a member of the family Bunyaviridae, possibly within the Bunyavirus genus.

ISSN:0004-945X    

DOI:10.1038/icb.1983.18

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryWe have characterized members of the Mapputta group of ‘bunya‐virus‐like’ viruses in terms of morphology, structure, ultrastructural development and virus‐directed RNA and protein synthesis. Our primary study has been with Maprik virus (MPK) as a representative of the group. The MPK virion is uniformly spherical (≃ 90 nm diameter) and possesses a membrane envelope. Virus maturation is by budding into small vesicles in the perinuclear region. During infection of BHK cells which is cytopathic, maximum viral RNA synthesis is ≃ 20% of RNA synthesis in uninfected cells without actinomycin D. InAedes alboplctuscells, where high initial titres are followed by a persistent infection, maximum viral RNA synthesis is only 1·5% of levels in control cells. MPK virions contain three RNA species. MPK generates four virus‐specific RNAs (L, M, S1 and S2) and three nucleocapsid species in infected BHK cells. Six virus‐specific polypeptides are present in infected cells; the four largest correspond to L (a probable transcriptase component), G1 and G2 (envelope proteins) and N (the nucleocapsid protein), respectively. These results and complementary studies with Trubanaman and Gan Gan viruses indicate that the members of the Mapputta serogroup can be placed in thebunyavirusgenus of the family Bunya‐viridae.

ISSN:0004-945X    

DOI:10.1038/icb.1983.19

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryLocal anaesthetic drugs were instilled into the pericardial sac of conscious rabbits through a chronically implanted catheter. Twenty mg of procaine HCl always caused complete blockade of cardiac vagal and sympathetic efferent nerves, tested by eliciting the baroreceptor‐heart rate reflex, and abolished the reflex depression of renal sympathetic nerve activity elicited by impeding left ventricular outflow. It also slowed heart rate by a direct effect on the sinoatrial pacemaker. When the same dose of procaine was given intravenously there were only transient changes in blood pressure, heart rate and the baroreceptor‐heart rate reflex. Lignocaine HCl and bupivacaine HCl were relatively less effective in blocking cardiac sympathetic efferent nerves. Intrapericardial procaine can be used in conscious animals to elucidate the part played by the cardiac receptor reflexes in control of the circulation.

ISSN:0004-945X    

DOI:10.1038/icb.1983.20

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryThe eggs of the cattle tick,Boophilus microplus, contain at least two proteolytic enzyme inhibitors which have been purified and partially characterized. One of these is closely related to an inhibitor from larval ticks previously purified. It is similar in general properties, in amino acid composition and it cross‐reacts immunologically with the larval protein. The egg and larval proteins are, however, largely or completely stage‐specific. The significance of this to the study of She host‐parasite interaction is discussed.

ISSN:0004-945X    

DOI:10.1038/icb.1983.21

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryAll six enzymes ofde novopyrimidine biosynthesis leading to the formation of UMP have been demonstrated in whole homogenates from two bovineBabesiaspecies,B. bovisandB. bigemina.The specific activities of the respective enzymes were of the same order of magnitude as observed for the related parasite,Plasmodium berghei.The results indicate that both these parasites have the potential of obtaining their pyrimidine requirements byde novosynthesis.Subcellular fractionation established that dihydroorotate dehydrogenase, the fourth enzyme of the pathway, was of a particulate nature. Mammalian respiratory chain inhibitors and ubiquinone analogues caused inhibition of theBabesiadihydroorotate dehydrogenase. As observed for other eukaryotic systems, the dehydrogenase appears to be linked to a respiratory chain via ubiquinone.

ISSN:0004-945X    

DOI:10.1038/icb.1983.22

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryThis study investigated the effect of splenectomy on the production of ablastin and the elimination ofTrypanosoma lewisifrom the circulation of infected Porton rats. Rats were splenectomized or sham‐splenectomized either before or at various stages during the infection and the course of the parasitaemia compared with untreated control animals. Ablastin titres in the serum were measured by a sensitivein vitroassay and were found to be the same in all the rats, regardless of the nature or timing of the operation. Splenectomized animals eliminated the parasite more slowly from the circulation than either the sham‐splenectomized animals or unoperated controls. It is concluded that the presence of the spleen enables the rat to clear the parasite more rapidly from the circulation, but that the spleen is not essential for the production ablastin during the infection.

ISSN:0004-945X    

DOI:10.1038/icb.1983.23

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY