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51.
R. E. Gilbert M. R. Stanford H. Jackson R. E. Holliman M. D. Sanders 《BMJ (Clinical research ed.)》1995,310(6986):1037-1040
OBJECTIVE--To determine the incidence of acute symptomatic toxoplasma retinochoroiditis presenting to ophthalmologists for patients born in Britain and elsewhere. DESIGN--Population based, cross sectional study. SETTING--11 districts in south Greater London. SUBJECTS--All patients presenting to NHS ophthalmologists with symptoms due to acute toxoplasma retinochoroiditis in 1992-3. MAIN OUTCOME MEASURE--Intraocular inflammation in association with a retinochoroidal scar, active adjoining retinitis, and IgG serum antibodies to toxoplasma. RESULTS--The estimated incidence of acute symptomatic retinochoroiditis for all people born in Britain was 0.4/100,000/year. If a mean of two symptomatic episodes per lifetime is assumed, 100 people born in Britain may be affected each year, about a fifth of the estimated 500-600 congenitally infected people born each year. CONCLUSIONS--A substantial proportion of people with acute symptomatic toxoplasma retinochoroiditis were born outside the country, and the number born in Britain was smaller than the number previously estimated to develop retinochoroidal lesions due to congenital toxoplasmosis. These findings suggest that prenatal screening for toxoplasmosis in Britain may be of limited benefit. 相似文献
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Guard cells of plants representing 18 species were assayed qualitatively for potential to conduct photosynthetic linear electron transport. These plants included C3 pteridophytes, C3 and C4 monocots, and C3, C4, and Crassulacean acid metabolism dicots. By use of a microfluorospectrophotometer, guard cell samples in epidermal peels were isolated optically. Chlorophyll fluorescence was monitored from the onset of excitation light. For guard cells of all these species, fluorescence intensity increased during illumination. When samples were preincubated with 3-(3,4-dichlorophenyl)-1,1-dimethylurea, diuron, however, there was a more rapid increase in fluorescence. These results indicate that all tested guard cells conduct photosynthetic electron transport through the reaction center of photosystem II. 相似文献
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The prevalence of hyperuricaemia and gout was investigated in the Micronesian inhabitants of the highly urbanised central Pacific island of Nauru. Sixty-four per cent of men and 60% of women aged 20 years and over had hyperuricaemia--the highest prevalence rates yet reported for a population. The hyperuricaemia in men was accompanied by a high prevalence of clinical gout (6.9%). While the hyperuricaemia is probably genetic, the high prevalence of gout may be related to the environmental change from the traditional island style of living to one of almost complete Westernisation. 相似文献
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Laird G. Jackson 《American journal of human genetics》1977,29(2):215-216
59.
The monolayer technique has been used to study the interaction of lipids with plasma apolipoproteins. Apolipoprotein C-II and C-III from human very low density lipoproteins, apolipoprotein A-I from human high density lipoproteins and arginine-rich protein from swine very low density lipoproteins were studied. The injection of each apoprotein underneath a monolayer of egg phosphatidyl[14C]choline at 20 mN/m caused an increase in surface pressure to approximately 30 mN/m. With apolipoprotein C-II and apolipoprotein C-III there was a decrease in surface radioactivity indicating that the apoproteins were removing phospholipid from the interface; the removal of phospholipid was specific for apolipoprotein C-II and apolipoprotein C-III. Although there was a removal of phospholipid from the monolayer, the surface pressure remained constant and was due to the accumulation of apoprotein at the interface. The rate of surface radioactivity decrease was a function of protein concentration, required lipid in a fluid state and, of the lipids tested, was specific for phosphatidylcholine. Cholesterol and phosphatidylinositol were not removed from the interface. The addition of 33 mol% cholesterol to the phosphatidylcholine monolayer did not affect the removal of phospholipid by apolipoprotein C-III.The addition of phospholipid liposomes to the subphase greatly facilitated the apolipoprotein C-II-mediated removal of phospholipid from the interface. 相似文献
60.
Elaine J. Davis Joel M. Blatt Eva K. Henderson Joseph J. Whittaker Julius H. Jackson 《Molecular & general genetics : MGG》1977,156(3):239-249
Summary Spontaneous mutants (146) of Escherichia coli K-12 were selected that were resistant to inhibition of growth by 1.2 mM L-valine (Valr). The Valr isolates, containing acetohydroxy acid synthase resistant to feedback inhibition by L-valine (AHASr), were classed according to cotransduction of the mutation with leu. Several mutations resulting in an AHASr phenotype were found to be cotransducible with glyA. However, no mutations causing a Valr phenotype were linked to ilv. AHAS activity was more closely examined in representatives of three classes of mutants with Valr linked to leu, labeled ilv-660, ilv-661, and ilv-662. The ilvE503 allele in E. coli K-12, known to cause a two- to three-fold derepression of AHAS, was found to affect regulation of synthesis of both valine-sensitive AHAS (AHASs) and AHASr in the mutants containing ilv-660 and ilv-661, whereas it affected repression of AHASs, only, in the mutant containing ilv-662. Further, both AHASs and AHASr in the ilv-661 mutant were repressed by valine, whereas valine did not repress AHASr synthesis in the strain carrying ilv-660 and only partially repressed AHASr in the strain carrying ilv-662. Unexpectedly, AHASr synthesis in strains carrying ilv-660 or ilv-662 was repressible by leucine. The ilv-660 locus appears to be similar in position to ilvH and encodes a product that confers valine-sensitivity upon AHAS activity in the wild-type E. coli K-12. The ilv-660 and ilv-662 loci may normally encode products that influence both the feedback sensitivity of AHAS and control of AHAS biosynthesis. 相似文献