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排序方式: 共有10000条查询结果,搜索用时 484 毫秒
61.
Koumans EH Black CM Markowitz LE Unger E Pierce A Sawyer MK Papp JR 《Journal of clinical microbiology》2003,41(4):1507-1511
62.
Rich JD Dickinson BP Macalino G Flanigan TP Towe CW Spaulding A Vlahov D 《Journal of acquired immune deficiency syndromes (1999)》1999,22(2):161-166
This study explores recent temporal trends in HIV prevalence among women entering prison and the incidence and associated risk factors among women reincarcerated in Rhode Island. Results from mandatory HIV testing from 1992 to 1996 for all incarcerated women were examined. In addition, a case control study was conducted on all seroconverters from 1989 to 1997. In all, 5836 HIV tests were performed on incarceration in 3146 women, 105 of whom tested positive (prevalence, 3.3%). Between 1992 and 1996, the annual prevalence of HIV among all women known to be HIV-positive was stable (p = .12). Age >25 years, nonwhite race, and prior incarceration were associated with seropositivity. Of 1081 initially seronegative women who were retested on reincarceration, 12 seroconverted during 1885 person-years (PY) of follow-up (incidence, 0.6/100 PY). Self-reported injection drug use (IDU; odds ratio [OR], 3.7; 95% confidence interval [CI], 1.3-10.1) was significantly associated with seroconversion, but sexual risk was not (OR, 1.1; 95% CI, 0.4-3.5). Incarceration serves as an opportunity for initiation of treatment and linkage to community services for a population that is at high risk for HIV infection. 相似文献
63.
Chinese hamster cells deficient in ornithine decarboxylase activity: Reversion by gene amplification and by azacytidine treatment 总被引:11,自引:0,他引:11
A group of Chinese hamster ovary (CHO) cell mutants deficient in ornithine decarboxylase (ODC) activity are described and compared to the prototype mutant reported previously (21). Although all mutants belong to the same complementation group, they can be divided into two classes: those with some residual enzyme activity and those with no activity. All mutants are putrescine auxotrophs, but they differ in their ability to utilize the enzyme's substrate, ornithine, a property which correlates with the amount of residual enzyme activity. The mutants also differ in their frequency of reversion to prototrophy. The leaky mutants revert at a high rate by overproducing a partially defective enzyme by a gene amplification mechanism similar to that leading to the ornithine analog-resistant mutants which have elevated enzyme levels. Spontaneous reversion in the null mutants is rare. However, one null mutant, which was induced with ethyl methane sulfonate and which makes ODC mRNA but no active enzyme, is nevertheless revertible with 5-azacytidine. We conclude that CHO cells are at least diploid at the ODC locus, but that only one allele is active. Further studies suggest the possibility that ethyl methane sulfonate is not just a classical mutagen but may also induce gene inactivations that are revertible by 5-azacytidine. 相似文献
64.
65.
Yvonne Myal Carolyn Gregory Hui Wang John L. Hamerton Robert P. C. Shiu 《Somatic Cell and Molecular Genetics》1989,15(3):265-270
The hormonally responsive prolactin-inducible protein (PIP), gene is expressed in benign and malignant breast tumor tissues and in such normal exocrine organs as sweat, salivary, and lacrimal glands. In this communication we report the regional chromosome localization of the PIPgene locus to chromosome 7 by Southern hybridization to DNA from human-hamster somatic cell hybrids, and to 7q32–36 by in situ hybridization. 相似文献
66.
67.
Dean K Whitla Gary Orfield William Silen Carole Teperow Carolyn Howard Joan Reede 《Academic medicine》2003,78(5):460-466
PURPOSE: Many U.S. medical schools have abandoned affirmative action, limiting the recruitment and reducing the admission of underrepresented minority (URM) students even though research supports the premise that the public benefits from an increase in URM physicians and that URM physicians are likely to serve minority, poor, and Medicaid populations. Faculty and students commonly assume they benefit from peer cultural exchange, and the published evidence for the past two decades supports this notion. This research examined the students' perceptions of the educational merits of a diverse student body by surveying medical students at two schools. METHOD: In 2000, medical students from all four years at Harvard Medical School and the University of California, San Francisco, School of Medicine were enrolled in a telephone survey about the relevance of racial diversity (among students) in their medical education. Students responded to the interviewer's questions on a five-point Likert-type scale. RESULTS: Of the 55% of students who could be located, 97% responded to the survey. Students reported having little intercultural contact during their formative years but significantly more interactions during higher education years, especially in medical school. Students reported contacts with diverse peers greatly enhanced their educational experience. They strongly supported strengthening or maintaining current affirmative action policies in admissions. The responses and demography of the Harvard and UCSF students did not differ significantly, nor did they differ for majority students and URM students-all groups overwhelmingly thought that racial and ethnic diversity among their peers enhanced their education. CONCLUSIONS: Diversity in the student body enhanced the educational experiences of students in two U.S. medical schools. 相似文献
68.
69.
Effect of low-frequency repetitive transcranial magnetic stimulation on interhemispheric inhibition 总被引:5,自引:0,他引:5
Pal PK Hanajima R Gunraj CA Li JY Wagle-Shukla A Morgante F Chen R 《Journal of neurophysiology》2005,94(3):1668-1675
We studied the effects of 1-Hz repetitive transcranial magnetic stimulation (rTMS) on the excitability of interhemispheric connections in 13 right-handed healthy volunteers. TMS was performed using figure-eight coils, and surface electromyography (EMG) was recorded from both first dorsal interosseous (FDI) muscles. A paired-pulse method with a conditioning stimulus (CS) to the motor cortex (M1) followed by a test stimulus to the opposite M1 was used to study the interhemispheric inhibition (ppIHI). Both CS and TS were adjusted to produce motor-evoked potentials of approximately 1 mV in the contralateral FDI muscles. After baseline measurement of right-to-left IHI (pre-RIHI) and left-to-right IHI (pre-LIHI), rTMS was applied over left M1 at 1 Hz with 900 stimuli at 115% of resting motor threshold. After rTMS, ppIHI was studied using both the pre-rTMS CS (post-RIHI and post-LIHI) and an adjusted post-rTMS CS set to produce 1-mV motor evoked potentials (MEPs; post-RIHI(adj) and post-LIHI(adj)). The TS was set to produce 1-mV MEPs. There was a significant reduction in post-LIHI (P = 0.0049) and post-LIHI(adj) (P = 0.0169) compared with pre-LIHI at both interstimulus intervals of 10 and 40 ms. Post-RIHI was significantly reduced compared with pre-RIHI (P = 0.0015) but pre-RIHI and post-RIHI(adj) were not significantly different. We conclude that 1-Hz rTMS reduces IHI in both directions but is predominantly from the stimulated to the unstimulated hemisphere. Low-frequency rTMS may be used to modulate the excitability of IHI circuits. Treatment protocols using low-frequency rTMS to reduce cortical excitability in neurological and psychiatric conditions need to take into account their effects on IHI. 相似文献
70.
Mervis CB Morris CA Klein-Tasman BP Bertrand J Kwitny S Appelbaum LG Rice CE 《Developmental neuropsychology》2003,23(1-2):243-268
Two studies were conducted to consider the looking behavior of infants and toddlers with Williams syndrome (WS).In Study 1,the looking behavior of a 10-month-old girl with WS during play sessions with her mother and with a stranger was compared to that of 2 groups of infants who were developing normally (ND),1 matched for chronological age and the other for developmental age. The infant with WS spent more than twice as much time looking at her mother as the infants in either contrast group did. She also spent twice as much time looking at the stranger.In addition, during 78%of this time, her gaze at the stranger was coded as extremely intense. Looks of this intensity were virtually never made by the ND infants. In Study 2,the looking behavior of 31 individuals with WS ages 8 to 43 months during a genetics evaluation was compared to that of 319 control children in the same age range (242 with developmental delay due to causes other than WS).Twenty-three of the 25 participants with WS aged 33 months or younger demonstrated extended and intense looking at the geneticist. In contrast, none of the control participants looked extensively or intently at the geneticist. Findings are discussed in the context of previous research on arousal and focused attention during normal development and on temperament and personality of older children and adults with WS. It is argued that the unusual looking patterns evidenced by infants and toddlers with WS presage the unusual temperament and personality of older individuals with WS, and the possibility of a genetic basis for these behaviors is addressed. 相似文献