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排序方式: 共有268条查询结果,搜索用时 32 毫秒
31.
Autoantibodies against platelet membrane glycoproteins in children with acute and chronic immune thrombocytopenic purpura 总被引:1,自引:0,他引:1
The autoimmune nature of chronic immune thrombocytopenic purpura (ITP) in adults is widely accepted. In contrast, the pathogenetic mechanism in acute and chronic ITP in children is not known. In this report, we studied 39 children with destructive thrombocytopenia, 15 patients with acute ITP and 24 patients with chronic ITP. Platelet autoantibodies to platelet glycoprotein IIb/IIIa were detected in 14 of 24 patients (58.3%) in the chronic ITP group and in four of 15 (26.7%) with acute ITP. Binding ratios (+/- SD) of positive patients were significantly greater (P = .01) in chronic ITP (8.0 +/- 9.1) when compared with those of acute ITP where the binding ratios were only slightly above the normal range (1.9 +/- 0.4). The results show that autoantibodies against platelet glycoproteins are present in the majority of children with chronic ITP confirming the autoimmune nature of this disorder. The minimal elevation seen in the positive children with acute ITP suggests a different pathogenetic mechanism. These data suggest that this approach may be useful in differentiating acute from chronic ITP patients. 相似文献
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Gulick RM Hu XJ Fiscus SA Fletcher CV Haubrich R Cheng H Acosta E Lagakos SW Swanstrom R Freimuth W Snyder S Mills C Fischl M Pettinelli C Katzenstein D 《The Journal of infectious diseases》2000,182(5):1375-1384
This study compared antiretroviral activity among 6 "salvage" therapy regimens. The study was a prospective, randomized, 2x3 factorial, multicenter study of the AIDS Clinical Trials Group. The study enrolled 277 human immunodeficiency virus (HIV)-infected patients naive to nonnucleoside analogues who had taken indinavir >6 months. The patients had 2000-200,000 HIV RNA copies/mL. Patients received saquinavir with ritonavir or nelfinavir together with delavirdine and/or adefovir and were followed for safety and antiretroviral response between baseline and week 16. At week 16, 30% (77/254) of patients had =500 HIV RNA copies/mL. Virologic response did not differ significantly between pooled ritonavir and nelfinavir groups (28% vs. 33%; P=.50) or between pooled delavirdine and delavirdine/adefovir groups (40% vs. 33%; P=.42). Pooled delavirdine groups had a greater virologic response rate than did adefovir groups (40% vs. 18%; P=.002). Overall, one-third of patients who experienced virologic failure on an indinavir-containing regimen suppressed virus load levels while they were taking a new salvage regimen. 相似文献
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Gudlavalleti VS Murthy Samantha Fox Selvaraj Sivasubramaniam Clare E Gilbert Abdull M Mahdi Abdullahi U Imam Gabriel Entekume Abiose Adenike Olufunmilayo O Bankole C Ezelum Fatima Kyari Mansur M Rabiu Hannah Faal Pak Sang Lee Abubakar Tafida 《Cardiovascular journal of Africa》2013,24(9):344-350
Hypertension is increasingly being recognised as an important public health problem in sub-Saharan Africa, with 26.9% of men and 28.4% of women in 2000 being estimated to have hypertension.1 Although lower than the prevalence in high-income countries (37.4% in men and 37.2% in women), in terms of numbers of people affected, the burden of hypertension in low- and middle-income countries is greater due to the large population.1Hypertension has been recognised as a strong independent risk factor for heart disease and stroke and a predictor of premature death and disability from cardiovascular complications.2 It has been reported that 13.5% of deaths and 6% of disability-adjusted life years (DALYs) were attributed to hypertension globally, and for low- and middle income people, these figures were 12.9 and 5.6%, respectively over the period 1990 to 2001.3 Although infectious diseases remain the leading cause of mortality and morbidity in sub-Saharan Africa, the prevalence of cardiovascular disease and hypertension is rising rapidly.4It has been emphasised that urbanisation is a key reason for the increasing rates of hypertension, as evidenced by the higher prevalence of hypertension in urban areas.4-6 Urban lifestyles, characterised by sedentary living, increased salt intake, obesity and stress contribute to these differences.5 With the urban population in sub-Saharan Africa projected to increase, a greater risk of hypertension is anticipated.Studies on the association between ethnicity and hypertension in high-income countries have documented a higher prevalence of hypertension in black ethnic groups compared to white ethnic groups.7-9 Reasons for this association are complex, unclear and much debated, reflecting genetic and biochemical mechanisms, and environmental and socio-economic factors.10,11 There is limited evidence regarding differences in the prevalence of hypertension between ethnic groups within the broader classification of black ethnicity.6,12,13Studies in Nigeria and sub-Saharan Africa have mainly involved specific geographical areas or have focused on sub-groups of the population.5,14 Surveys from Nigeria report prevalence estimates ranging from 20.2 to 36.6%, but all have involved participants with different age ranges.15-18 To plan services for hypertension in Nigeria, it is essential to have accurate prevalence estimates for the whole population and to identify populations at risk.Nigeria, which is the most populous country in sub-Saharan Africa, is home to over 250 different ethnic groups. Nigeria is experiencing rapid urbanisation of the population, which is likely to increase the population at risk for hypertension.19 The present study is one of the largest population-based surveys in the region and is able to provide a nationally representative estimate of hypertension for Nigeria. 相似文献
35.
A gradient in the duration of the G1 phase in the murine neocortical proliferative epithelium 总被引:8,自引:6,他引:2
Miyama S; Takahashi T; Nowakowski RS; Caviness VS Jr 《Cerebral cortex (New York, N.Y. : 1991)》1997,7(7):678-689
Neuronogenesis in the neocortical pseudostratified ventricular epithelium
(PVE) is initiated rostrolaterally and progresses caudo- medially as
development progresses. Here we have measured the cytokinetic parameters
and the fractional neuronal output parameter, Q, of laterally located
early-maturing regions over the principal embryonic days (E12-E15) of
neocortical neuronogenesis in the mouse. These measures are compared with
ones previously made of a medial, late- maturing portion of the PVE.
Laterally, as medially, the duration of the neuronogenetic interval is 6
days and comprises 11 integer cell cycles. Also, in both lateral and medial
areas the length of G1 phase (TG1) increases nearly 4-fold and is the only
cell cycle parameter to change. Q progresses essentially identically
laterally and medially with respect to the succession of integer cell
cycles. Most importantly, from E12 to E13 there is a steeply declining
lateral to medial gradient in TG1. The gradient is due both to the lateral
to medial graded stage of neuronogenesis and to the stepwise increase in
TG1 with each integer cycle during the neuronogenetic interval. To our
knowledge this gradient in TG1 of the cerebral PVE is the first cell
biological gradient to be demonstrated experimentally in such an extensive
proliferative epithelial sheet. We suggest that this gradient in TG1 is the
cellular mechanism for positionally encoding a protomap of the neocortex
within the PVE.
相似文献
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The initiation and termination sites of replication of vaccinia DNA has been studied by determining the radioactivity in restriction fragments of the pulse-labeled newly synthesized molecules. The results indicate a bimodal distribution of radioactivity in the molecules completed during a pulse shorter than the completion time of synthesis, implying termination at both ends. The symmetry of replication was studied by hybridization of an intermediate in replication (34 S) to the isolated strands of virion DNA followed by restriction analysis. The frequency of hybridization of the fragments to the light or heavy strand shows a unimodal distribution of radioactivity indicating asymmetric replication. Together, these observations suggest that initiation and termination sites are located at both ends of the chromosome. Changes observed in the conformation of parental DNA at the time of replication, such as high degree of single-strandness, are compatible with strand displacement during synthesis. 相似文献
39.
Freimuth VS 《Health communication》2006,20(2):141-148
This article describes 5 communication challenges faced by the author as she managed the communication response by the Centers for Disease Control and Prevention to the anthrax attacks of 2001: communicating uncertainty, selecting credible spokespersons, collaborating with other organizations, satisfying a competitive 24/7 media, and speed. The lessons learned in responding to these challenges led to profound changes in the way communication was organized in the agency. These changes are described within the framework of chaos theory. 相似文献
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