排序方式: 共有21条查询结果,搜索用时 15 毫秒
1.
A case of trisomy 22 in Pongo pygmaeus. 总被引:1,自引:0,他引:1
A behaviorally and clinically abnormal female orangutan was analyzed cytologically using general banding techniques and by an alkaline silver method for staining nucleolus organizer regions. The karyotype had 49 chromosomes, including an extra chromosome 22 (49,XX + 22). No variant chromosome types or heterozygous structural rearrangements were found. Nine of the 14 large acrocentric chromosomes, Nos. 11--17, and three of the five presumptive human G-group equivalents, i.e., two of three chromosomes 22, and one chromosome from pair 23, exhibited positive silver staining of the nucleolus organizer region (NOR). 相似文献
2.
Summary Two unrelated cases of 4q trisomy are described with trisomic segment 4q254qter. The most conspicuous symptoms are psychomotor retardation, microcephaly, malformed ears, retrognathia, finger and toe malformations and cryptorchism in a male. Both cases are compared with 19 previously reported ones.To whon offprints requests should be sent 相似文献
3.
Caoimhe Cawley Alison Wringe Raphael Isingo Baltazar Mtenga Benjamin Clark Milly Marston Jim Todd Mark Urassa Basia Zaba 《PloS one》2013,8(4)
Background
HIV counselling and testing (HCT) services can play an important role in HIV prevention by encouraging safe sexual behaviours and linking HIV-infected clients to antiretroviral therapy (ART). However, regular repeat testing by high-risk HIV-negative individuals is important for timely initiation of ART as part of the ‘treatment as prevention’ approach.Aim
To investigate HCT use during a round of HIV serological surveillance in northwest Tanzania in 2010, and to explore rates of repeat testing between 2003 and 2010.Methods
HCT services were provided during the fourth, fifth and sixth rounds of serological surveillance in 2003–2004 (Sero-4), 2006–2007 (Sero-5) and 2010 (Sero-6). HCT services have also been available at a government-run health centre and at other clinics in the study area since 2005. Questionnaires administered during sero-surveys collected information on socio-demographic characteristics, sexual behaviour and reported previous use of HCT services.Results
The proportion of participants using HCT increased from 9.4% at Sero-4 to 16.6% at Sero-5 and 25.5% at Sero-6. Among participants attending all three sero-survey rounds (n = 2,010), the proportions using HCT twice or more were low, with 11.1% using the HCT service offered at sero-surveys twice or more, and 25.3% having tested twice or more if reported use of HCT outside of sero-surveys was taken into account. In multivariable analyses, individuals testing HIV-positive were less likely to repeat test than individuals testing HIV-negative (aOR 0.17, 95% CI 0.006–0.52).Discussion/Conclusions
Although HCT service use increased over time, it was disappointing that the proportions ever testing and ever repeat-testing were not even larger, considering the increasing availability of HCT and ART in the study area. There was some evidence that HIV-negative people with higher risk sexual behaviours were most likely to repeat test, which was encouraging in terms of the potential to pick-up those at greatest risk of HIV-infection. 相似文献4.
Milly Marston Jessica Nakiyingi-Miiro Victoria Hosegood Tom Lutalo Baltazar Mtenga Basia Zaba 《PloS one》2016,11(3)
Background
UNAIDS official estimates of national HIV prevalence are based on trends observed in antenatal clinic surveillance, after adjustment for the reduced fertility of HIV positive women. Uptake of ART may impact on the fertility of HIV positive women, implying a need to re-estimate the adjustment factors used in these calculations. We analyse the effect of antiretroviral therapy (ART) provision on population-level fertility in Southern and East Africa, comparing trends in HIV infected women against the secular trends observed in uninfected women.Methods
We used fertility data from four community-based demographic and HIV surveillance sites: Kisesa (Tanzania), Masaka and Rakai (Uganda) and uMkhanyakude (South Africa). All births to women aged 15–44 years old were included in the analysis, classified by mother’s age and HIV status at time of birth, and ART availability in the community. Calendar time period of data availability relative to ART Introduction varied across the sites, from 5 years prior to ART roll-out, to 9 years after. Calendar time was classified according to ART availability, grouped into pre ART, ART introduction (available in at least one health facility serving study site) and ART available (available in all designated health facilities serving study site). We used Poisson regression to calculate age adjusted fertility rate ratios over time by HIV status, and investigated the interaction between ART period and HIV status to ascertain whether trends over time were different for HIV positive and negative women.Results
Age-adjusted fertility rates declined significantly over time for HIV negative women in all four studies. However HIV positives either had no change in fertility (Masaka, Rakai) or experienced a significant increase over the same period (Kisesa, uMkhanyakude). HIV positive fertility was significantly lower than negative in both the pre ART period (age adjusted fertility rate ratio (FRR) range 0.51 95%CI 0.42–0.61 to 0.73 95%CI 0.64–0.83) and when ART was widely available (FRR range 0.57 95%CI 0.52–0.62 to 0.83 95%CI 0.78–0.87), but the difference has narrowed. The interaction terms describing the difference in trends between HIV positives and negatives are generally significant.Conclusions
Differences in fertility between HIV positive and HIV negative women are narrowing over time as ART becomes more widely available in these communities. Routine adjustment of ANC data for estimating national HIV prevalence will need to allow for the impact of treatment. 相似文献5.
6.
Becquet R Marston M Dabis F Moulton LH Gray G Coovadia HM Essex M Ekouevi DK Jackson D Coutsoudis A Kilewo C Leroy V Wiktor SZ Nduati R Msellati P Zaba B Ghys PD Newell ML;UNAIDS Child Survival Group 《PloS one》2012,7(2):e28510
BACKGROUND: Assumptions about survival of HIV-infected children in Africa without antiretroviral therapy need to be updated to inform ongoing UNAIDS modelling of paediatric HIV epidemics among children. Improved estimates of infant survival by timing of HIV-infection (perinatally or postnatally) are thus needed. METHODOLOGY/PRINCIPAL FINDINGS: A pooled analysis was conducted of individual data of all available intervention cohorts and randomized trials on prevention of HIV mother-to-child transmission in Africa. Studies were right-censored at the time of infant antiretroviral initiation. Overall mortality rate per 1000 child-years of follow-up was calculated by selected maternal and infant characteristics. The Kaplan-Meier method was used to estimate survival curves by child's HIV infection status and timing of HIV infection. Individual data from 12 studies were pooled, with 12,112 children of HIV-infected women. Mortality rates per 1,000 child-years follow-up were 39.3 and 381.6 for HIV-uninfected and infected children respectively. One year after acquisition of HIV infection, an estimated 26% postnatally and 52% perinatally infected children would have died; and 4% uninfected children by age 1 year. Mortality was independently associated with maternal death (adjusted hazard ratio 2.2, 95%CI 1.6-3.0), maternal CD4<350 cells/ml (1.4, 1.1-1.7), postnatal (3.1, 2.1-4.1) or peri-partum HIV-infection (12.4, 10.1-15.3). CONCLUSIONS/RESULTS: These results update previous work and inform future UNAIDS modelling by providing survival estimates for HIV-infected untreated African children by timing of infection. We highlight the urgent need for the prevention of peri-partum and postnatal transmission and timely assessment of HIV infection in infants to initiate antiretroviral care and support for HIV-infected children. 相似文献
7.
Variegation mutants and mechanisms of chloroplast biogenesis 总被引:6,自引:0,他引:6
Yu F Fu A Aluru M Park S Xu Y Liu H Liu X Foudree A Nambogga M Rodermel S 《Plant, cell & environment》2007,30(3):350-365
Variegated plants typically have green‐ and white‐sectored leaves. Cells in the green sectors contain normal‐appearing chloroplasts, whereas cells in the white sectors lack pigments and appear to be blocked at various stages of chloroplast biogenesis. Variegations can be caused by mutations in nuclear, chloroplast or mitochondrial genes. In some plants, the green and white sectors have different genotypes, but in others they have the same (mutant) genotype. One advantage of variegations is that they provide a means of studying genes for proteins that are important for chloroplast development, but for which mutant analysis is difficult, either because mutations in a gene of interest are lethal or because they do not show a readily distinguishable phenotype. This paper focuses on Arabidopsis variegations, for which the most information is available at the molecular level. Perhaps the most interesting of these are variegations caused by defective nuclear gene products in which the cells of the mutant have a uniform genotype. Two questions are of paramount interest: (1) What is the gene product and how does it function in chloroplast biogenesis? (2) What is the mechanism of variegation and why do green sectors arise in plants with a uniform (mutant) genotype? Two paradigms of variegation mechanism are described: immutans (im) and variegated2 (var2). Both mechanisms emphasize compensating activities and the notion of plastid autonomy, but redundant gene products are proposed to play a role in var2, but not in im. It is hypothesized that threshold levels of certain activities are necessary for normal chloroplast development. 相似文献
8.
Attema-de Jonge ME Bekkers JM Oudemans-van Straaten HM Sparidans RW Franssen EJ 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2008,862(1-2):257-262
After oral administration of tobramycin, as part of selective decontamination of the digestive tract (SDD) in critically ill patients, absorption of tobramycin from the gut into the blood may take place. To quantify low concentrations of tobramycin in human plasma, we developed and validated a simple (sample pre-treatment consisting of protein precipitation with acetonitrile using 200microl plasma), rapid (runtime 3min using a Pathfinder MR reversed-phase column) and sensitive (concentration range of 0.05-1.0mg/l using MS/MS detection) method. 相似文献
9.
Summary A 5-year-old male with multiple malformations (dwarfism, microcephalia with brachycephalic shape of skull, mongoloid lid axis, epicanthus, convergent strabismus, flat root of the nose, micrognathia, missing uvula, deformed low-set ears, hypoplastic genitals, and general hypotonia), severe mental retardation, and cerebral paroxysms caused by a partial monosomy (1)(q42qter) is described. This case is compared with other cases with a partial monosomy or ring-1 chromosomes.To whom offprint requests should be sent 相似文献
10.
Cynthia Sung Yuan Wei Satoru Watanabe How Sung Lee Yok Moi Khoo Lu Fan Abhay P. S. Rathore Kitti Wing-Ki Chan Milly M. Choy Uma S. Kamaraj October M. Sessions Pauline Aw Paola F. de Sessions Bernett Lee John E. Connolly Martin L. Hibberd Dhanasekaran Vijaykrishna Limin Wijaya Eng Eong Ooi Jenny Guek-Hong Low Subhash G. Vasudevan 《PLoS neglected tropical diseases》2016,10(8)