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排序方式: 共有367条查询结果,搜索用时 15 毫秒
1.
V. Cencora F. Challoner S. Gooch A. Livingstone D. Widgery 《BMJ (Clinical research ed.)》1988,297(6646):481-483
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Frank B. Livingstone 《American journal of human genetics》1971,23(5):543-544
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Ataxia-telangiectasia is a syndrome of progressive cerebellar ataxia and other neurological manifestations associated with conjunctival and cutaneous telangiectases and with recurrent sino-pulmonary infections. Immunological and endocrine abnormalities occur. Two girls with this disease are described. The first had only minor respiratory infections; her serum proteins and immunity responses appeared normal. The second had recurrent pulmonary infections and bronchiectasis; she also exhibited sclerodermatous changes, poor development of secondary sexual characteristics with low urinary excretion of 17-ketosteroids, and lymphopenia. Autopsy at 17 years showed bilateral ovarian dysgerminomata and excessive cutaneous collagen as well as atrophy, and perhaps hypoplasia, of adrenals, thymus, spleen and lymphoid tissue (after steroid therapy). The cerebellum exhibited cortical degeneration. Both lungs were fibrotic with old and recent bronchopneumonia and bronchiectasis. The left lung was studied by injection of a latex preparation; no arteriovenous aneurysms were found, but the smaller pulmonary vessels showed some unusual morphological characteristics. 相似文献
7.
The antioxidant enzymes superoxide dismutase (SOD; EC 1.15.1.1), catalase (EC 1.11.1.6), selenium-dependent glutathione peroxidase (SeGPX; EC 1.11.1.9), glutathione reductase (EC 1.6.4.2) and DT-diaphorase (EC 1.6.99.2), plus total GPX activity (sum of SeGPX and Se-independent GPX activities), were studied in 13 500 g supernatants of embryos and 3-day and 11-day post-hatch larvae of turbot Scophthalmus maximus L. SOD activity decreased progressively during development from embryos to 11-day-old larvae, indicative of a decreased need to detoxify superoxide anion radical (O2 − ). In contrast, catalase, SeGPX and glutathione reductase activities increased progressively from embryos to 11-day-old larvae, indicative of an increased need to metabolize hydrogen peroxide (H2 O2 ) and organic peroxides. Consistent with the latter changes, levels of lipid peroxides (i.e. thiobarbituric acid reactive substances) increased 13-fold from embryos to 3-day-old larvae, whilst total peroxidizable lipid was indicated to decrease. Increases were seen for NADPH-dependent DT-diaphorase (after hatching) and total GPX (between 3 and 11 days post-hatch) activities, whilst no change was found in NADH-dependent DT-diaphorase activity. Overall, the results demonstrate a capacity for early life-stages of S. maximus to detoxify reactive oxygen species (O2 − and H2 O2 ) and other pro-oxidant compounds (organic peroxides, redox cycling chemicals). Furthermore, qualitative and quantitative antioxidant changes occur during hatching and development, possibly linked to such events as altered respiration rates (SOD changes) and tissue reorganization and development (catalase, SeGPX, lipid peroxidation). 相似文献
8.
mtDNA diversity in rhesus monkeys reveals overestimates of divergence time and paraphyly with neighboring species 总被引:4,自引:0,他引:4
Reconstructions of the human-African great ape phylogeny by using
mitochondrial DNA (mtDNA) have been subject to considerable debate. One
confounding factor may be the lack of data on intraspecific variation. To
test this hypothesis, we examined the effect of intraspecific mtDNA
diversity on the phylogenetic reconstruction of another Plio- Pleistocene
radiation of higher primates, the fascicularis group of macaque (Macaca)
monkey species. Fifteen endonucleases were used to identify 10 haplotypes
of 40-47 restriction sites in M. mulatta, which were compared with similar
data for the other members of this species group. Interpopulational,
intraspecific mtDNA diversity was large (0.5%- 4.5%), and estimates of
divergence time and branching order incorporating this variation were
substantially different from those based on single representatives of each
species. We conclude that intraspecific mtDNA diversity is substantial in
at least some primate species. Consequently, without prior information on
the extent of genetic diversity within a particular species, intraspecific
variation must be assessed and accounted for when reconstructing primate
phylogenies. Further, we question the reliability of hominoid mtDNA
phylogenies, based as they are on one or a few representatives of each
species, in an already depauperate superfamily of primates.
相似文献
9.
C Livingstone A R McLellan M A McGregor A Wilson J M Connell M Small G Milligan K R Paterson M D Houslay 《Biochimica et biophysica acta》1991,1096(2):127-133
Adenylate cyclase activity and levels of guanine nucleotide regulatory proteins (G-proteins) were compared in platelets from normal and non-insulin-dependent diabetic (NIDDM) male subjects. Whilst no differences were noted in basal and NaF-stimulated adenylate cyclase activities the degree of stimulation achieved by both forskolin and prostaglandin, E1 was lower by some 34 and 52% respectively, in platelet membranes from diabetic subjects compared with those from normal control subjects. Altered alpha 1-adrenoceptor-mediated inhibition of prostaglandin E1-stimulated adenylate cyclase activity was evident; it being some 34% lower in platelet membranes from diabetic subjects compared to controls. Analysis of G-protein alpha-subunits, using specific anti-peptide antisera, showed that platelets from all subjects exhibited the Gi-2 and Gi-3, but not the Gi-1 forms of the inhibitory G-protein 'Gi' and all expressed the 42 kDa species of alpha-subunit of the stimulatory G-protein Gs. Whilst platelets of diabetic subjects had levels of Gs which were comparable to those found in control subjects their levels of Gi-2 and Gi-3 were some 49 and 75%, respectively, of those found in platelets from control subjects. It is suggested that changes in adenylate cyclase functioning and G-protein expression may contribute to altered platelet functioning in non-insulin-dependent diabetic subjects. 相似文献
10.
D Ribera J F Narbonne X Michel D R Livingstone S O'Hara 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1991,100(1-2):177-181
1. The aim of this work was to evaluate the relationships between free radical scavengers and lipid peroxidation in the common mussel Mytilus edulis. 2. Mussels were exposed to compounds known for their ability to produce free radicals (carbon tetrachloride, CCl4) and reactive oxygen species via redox cycling (menadione) and the effects on digestive gland, gills and remaining tissues were studied. 3. Lipid peroxidation parameters and the status of free radical scavengers (glutathione, vitamins A, E and C) were affected more by exposure to menadione than to CCl4. 4. The observed changes in the free radical scavengers content are indicative of a role in detoxication of damaging reactive species. 相似文献