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991.
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The efficacy of injectable doramectin applied at 200 microg/kg was evaluated against adult female Boophilus microplus (Canestrini) (Acari: Ixodidae) in the later stages of engorgement before detachment. Lethal levels of doramectin in the serum of treated cattle (9.7-36.6 ppb) were reached and sustained within 24 h after treatment. However, treatment at 19 or 20 d postinfestation allowed greater tick survival and reproductive capability (IF) than at 18 d postinfestation, indicating that a significant portion of the ticks were able to engorge and detach before obtaining a lethal dose of doramectin. Thus, treatment at 18 d after infestation provided significantly higher overall control (99.5%) than treatment at 19 or 20 d postinfestation (95.8 and 89.1%, respectively). Analysis of control on a daily basis demonstrated that treatment at 18 d postinfestation provided > 99% on each day of the evaluation. Conversely, treatment at 19 or 20 d postinfestation produced levels of control ranging from 22.6 to 85.6% during the first 2 d of female detachment, and > or = 99% control was not achieved until after the fourth day of female detachment, where it remained throughout the study. Therefore, application of injectable doramectin at < or = 18 d after tick infestation was the only treatment regime considered acceptable for use in the U.S. Boophilus Eradication Program. Treatment intervals > 18 d postinfestation could pose a substantial risk of dispersing viable ticks to tick-free areas outside the permanent quarantine zone that has been established along the Texas-Mexico border.  相似文献   
995.
996.
Among risk factors for shoulder dystocia, a prior history of delivery complicated by shoulder dystocia is the single greatest risk factor for shoulder dystocia occurrence, with odds ratios 7 to 10 times that of the general population. Recurrence rates have been reported to be as high as 16%. Whereas prevention of shoulder dystocia in the general population is neither feasible nor cost-effective, intervention efforts directed at the particular subgroup of women with a prior history of shoulder dystocia can concentrate on potentially modifiable risk factors and individualized management strategies that can minimize recurrence and the associated significant morbidities and mortality.  相似文献   
997.
The decision by public health agencies to regulate specific microorganisms that may be found in drinking water can only be made if specific criteria find that a microorganism poses a health risk. These criteria should include: (1) there is a clinical history of an organism causing disease from the ingestion of drinking water; (2) there is epidemiological evidence that drinking water rather than food or other vectors is a major source of disease; (3) there is sufficient evidence that the target organism, if found in water, possesses virulence factors capable of causing disease in humans; (4) there is sufficient evidence that the target organism is not readily removed or inactivated by multi-barrier conventional water treatment process (e.g., coagulation-filtration-disinfection); (5) there is sufficient evidence that the target organism, if surviving conventional treatment, will be viable, virulent, and present in sufficient numbers to cause disease; (6) there are robust analytical methods for the target organism which have acceptable sensitivity, specificity, and reproducibility to measure accurately the presence of the target organism in treated water; and (7) the performance criteria of analytical method(s) for the target organism have been certified by the appropriate public health agency, and there is intra-laboratory field-test performance data to base this certification.  相似文献   
998.
Experimental studies have shown that blockade of the angiotensin II type-1 (AT(1)) receptor is effective in the mitigation and treatment of radiation-induced chronic renal failure. Also, blockade of the angiotensin II type-2 (AT(2)) receptor with PD-123319 also had a modest, but reproducible, beneficial effect in experimental radiation nephropathy, and it might augment the efficacy of an AT(1) blocker (L-158,809). Those studies could not exclude the possibility that the effects of AT(2) blockade were nonspecific. The current studies confirm the efficacy of AT(2) blockade for mitigation of experimental radiation nephropathy but paradoxically find no detectable level of AT(2) receptor binding in renal membranes. However, the results of a bioassay showed that the circulating levels of the AT(2) blocker were orders-of-magnitude too low to block AT(1) receptors. The effect of AT(2) blockade in radiation nephropathy cannot be explained by binding to the AT(1) receptor, and the efficacy of the AT(1) blockade in the same model cannot be explained by unopposed overstimulation of the AT(2) receptor.  相似文献   
999.
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BACKGROUND/OBJECTIVE: The AIDS Clinical Trials Group (ACTG) Adherence Questionnaire is used extensively, but investigators frequently only use the first item of the questionnaire (4-day recall). DESIGN/METHODS: A secondary analysis was conducted to (1) estimate the validity and reliability of each of the 5 scale items and (2) compare the approach commonly used to summarize adherence data collected with the instrument (average 4-day recall) with alternate approaches derived using principal component (PC) analysis and the full questionnaire. We hypothesized that an estimate of adherence taking all items of the questionnaire into account would provide a stronger measure of adherence. RESULTS: Logistic regression analyses showed that the first PC identified (PC1) was significantly correlated with plasma HIV RNA outcome (P < 0.0001 for ACTG 370 data and P = 0.006 for ACTG 398 data) and correlated with plasma HIV RNA better than average 4-day recall. An adherence index formulated using weights of PC1 showed substantially greater variability in the range of adherence scores in comparison to average 4-day adherence recall alone. PC1 compared favorably with 2 indices derived from medication event monitoring system data as well. CONCLUSIONS: Findings indicate that a superior assessment of antiretroviral adherence may be obtained with the ACTG Adherence Questionnaire by using the method employed in this analysis.  相似文献   
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