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231.
ShorttermefectofSalviamiltiorhizaintreatingrataceticacidchronicgastriculcerandlongtermefectinpreventingrecurenceWANGGuoZho...  相似文献   
232.
The Transfusion Safety Study (TSS) and the National Heart, Lung, and Blood Institute (NHLBI) established a repository of approximately 200,000 sera from blood donors in late 1984 and early 1985. Collections were made in the four metropolitan areas with the highest prevalence of AIDS. Retrospective testing showed an overall anti-HIV-1 prevalence of 16 cases per 10,000 donations. In this study, the predictive value of a negative initial enzyme-linked immunoassay was estimated from both quality control specimens and the rescreening of 13,461 sera to be greater than 99.99 percent with respect to technical error. Among anti-HIV-1-positive persons, there was a 1.3- to 1.5-fold excess of first-time donors. The anti-HIV-1 prevalence among donors showed that infection was more common among young men than suggested by national reporting of AIDS cases. Anti-HIV-1 prevalence varied among the four metropolitan areas less than did reported AIDS cases, but, by 1987, the differences in the latter had decreased. Anti-HIV-1 prevalence in collection areas outside of the four major cities differed much more widely than that among the cities themselves. The TSS/NHLBI Donor Repository will remain available for the indefinite future for further evaluation of screening procedures for HIV-1 and other viruses for which transfusion is found to be an important route of transmission.  相似文献   
233.
Down syndrome (DS) children with acute myeloid leukemia (AML) have significantly higher event-free survival (EFS) rates compared with non- DS children when treated with protocols containing 1-beta-D- arabinofuranosylcytosine (ara-C). Sensitivity and metabolism of ara-C was examined in myeloblasts from DS and non-DS patients with AML, DS infants with the transient myeloproliferative disorder, and Epstein- Barr Virus (EBV) transformed lymphoblastoid cell lines with and without trisomy 21. DS myeloblasts were approximately 10-fold more sensitive to ara-C (measured by the 3-[4,5-dimethyl-thiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) colorimetric sensitivity assay), compared with non-DS myeloblasts, following exposure to ara-C for 72 hours. Mean levels of l-beta-D-arabinofuranosylcytosine 5'-triphosphate (ara-CTP) were significantly higher in DS myeloblasts compared with non-DS myeloblasts after incubation with 5 micromol/L ara-C (621.4 v 228.4 pmol/mg protein). DS cell lines also generated higher levels of ara-CTP compared with cell lines with diploid chromosome numbers (66.5 v 13.6 pmol/mg protein and 137.6 v 41.7 pmol/mg protein at 1 and 5 micromol/L ara-C, respectively). Elevated ara-CTP levels in the DS cells were accompanied by slightly lower levels of endogenous deoxycytidine triphosphate (dCTP) pools, slightly greater extent of ara-C incorporation into DNA, and increased relative numbers of double strand DNA strand breaks. There were no significant differences in the cell cycle distributions of DS and non-DS cells. These in vitro studies support our hypothesis that enhanced metabolism of ara-C in DS cells may be a contributing factor to the superior survival rate of DS children with AML and is possibly based on a gene dosage effect of genes localized to chromosome 21 including cystathionine-beta-synthase. Further study of the mechanisms (ie, alterations in dCTP pools and DNA methylation) involved may lead to improvements in the treatment of all AML patients.  相似文献   
234.
Although the number of cases of tuberculosis in Navarre has fallen in recent years, it is necessary to adapt the control programs to the new situation. The keys to advancing in its prevention and control are: obtaining an early diagnosis and an effective treatment of patients and detecting and treating people with a latent infection. Primary care plays an important role in both activities. Half of the cases of active tuberculosis that are diagnosed have been contacts by bacilliferous TB patients or else have had a high personal predisposition to developing the disease. That is why detection and treatment of the latent infection in our setting must be carried out: 1) through screening persons at high risk of becoming infected and developing the disease, and 2) trough a systematic study of contacts of persons with the disease. In the treatment of both active tuberculosis and latent infection it is essential to obtain good patient adherence.  相似文献   
235.
236.
Liu  SC; Derick  LH; Palek  J 《Blood》1993,81(2):522-528
Red blood cells (RBCs) in sickle cell anemia, transformed into a sickled shape by prolonged deoxygenation, or normal RBCs deformed by a prolonged micropipette aspiration become permanently stabilized in their abnormal shape. This semisolid plastic behavior is thought to involve an irreversible reorganization of the membrane skeleton, but the exact nature of this skeletal rearrangement is not known. In this study, we first asked whether the irreversible deformation is associated with a permanent stretching of the skeletal network, and then whether it is due to a rearrangement of skeletal components involving a disruption of pre-existing protein associations and the subsequent reassociation of new protein contacts. Having found no ultrastructural evidence of stretching of the skeletal lattice in membranes derived from permanently deformed RBCs, we addressed the possibility of reorganization of the proteins of the membrane skeleton. We examined the temperature dependence of irreversible cell deformation to see if it correlated with the known temperature dependence of spectrin tetramers to dimer dissociation and reassociation. Testing the shape irreversibility of both deoxygenated reversibly sickled cells and Nucleopore-aspirated normal cells, we found that both types of cells became permanently deformed when the prolonged incubation of applied force or deoxygenation was performed at 37 degrees C, the temperature at which spectrin tetramers were free to dissociate and reassociate. In contrast, both types of cells were able to regain their original discocytic shape if the prolonged incubation was performed at the lower temperature: at less than 13 degrees C instead of 37 degrees C. Furthermore, normal RBCs were incubated with inosine and pyruvate to elevate intracellular 2,3-diphosphoglycerate, the polyanion shown to destabilize spectrin-actin-protein 4.1 association. This did not result in a promotion of irreversible deformation of these cells. We conclude that the irreversible cell deformation observed at physiologic temperature is associated with a skeletal rearrangement through dissociation of spectrin tetramers to dimers and a subsequent reassociation of dimers to tetramers in the new (deformed) configuration. These findings may explain a permanent stabilization of irreversibly sickled cells in their abnormal shape in vivo.  相似文献   
237.
238.
In open ecological systems, community structure can be determined by physically modulated processes such as the arrival of individuals from a regional pool and by local biological interactions. There is debate centering on whether niche differentiation and local interactions among species are necessary to explain macroscopic community patterns or whether the patterns can be generated by the neutral interplay of dispersal and stochastic demography among ecologically identical species. Here we evaluate how much of the observed spatial variation within a rocky intertidal metacommunity along 800 km of coastline can be explained by drift in the structure of recruits across 15 local sites. Our results show that large spatial changes in recruitment do not explain the observed spatial variation in adult local structure and that, in comparison with the large drift in structure of recruits, local adult communities converged to a common, although not unique, structure across the region. Although there is no unique adult community structure in the entire region, the observed variation represents only a small subset of the possible structures that would be expected from passive recruitment drift. Thus, in this diverse system our results do not support the idea that rocky intertidal metacommunities are structured by neutral mechanisms.  相似文献   
239.
Comparison of the results of first and second cataract eye surgery   总被引:7,自引:0,他引:7  
OBJECTIVE: To compare the outcomes of second eye cataract surgery with those of first eye surgery. In particular, to evaluate changes in visual acuity (VA), visual function, and health status after the first and second eye surgeries. DESIGN: A cohort (case series) analysis of patients recruited in a clinical trial. PARTICIPANTS: A total of 403 consecutive patients with indication of noncombined first eye or second eye cataract surgery were recruited in 3 public hospitals in Barcelona, Spain. First eye surgery patients are compared to second eye surgery patients. INTERVENTION: Patients were evaluated both before surgery and 4 months after surgery by a standardized telephone interview and clinical examination. MAIN OUTCOME MEASURES: Visual acuity, visual function index (VF-14), a 14-item instrument designed to measure visual function, and the Sickness Impact Profile (SIP), a generic measure of health status. RESULTS: Full data were obtained from 315 (78%) patients: 249 who underwent first eye surgery only and 66 different patients who underwent second eye surgery. Significant improvement was found in both groups of patients for best-corrected VA in the operated eye (4.4 Snellen lines, P < 0.001; 4.2 Snellen lines, P < 0.001, respectively), VA in the better eye (2.8 Snellen lines, P < 0.001; 1.4 Snellen lines, P < 0.001), and visual function (26.3 Snellen lines, P < 0.001; 17.0 Snellen lines; P < 0.001). Four months after the operation, the VF-14 of the second eye group was slightly better (93.4 vs. 88.5; P = 0.09; score range: 0, worst, to 100, best). Psycho-social SIP scores improved in both groups (4.8, P < 0.001; 3.1, P = 0.016). Physical SIP score improved only in the first eye surgery group (1.8, P = 0.003) but not in the second eye surgery group (-1.0, P = 0.338; score range: 0, best, to 100, worst). CONCLUSIONS: The results of our study suggest that patients undergoing second eye cataract surgery show significant improvements in VA, visual function, and psycho-social health status. However, global and physical health status does not change after second eye cataract surgery.  相似文献   
240.
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