No abstract

A-CASI was associated with greater reporting of potentially stigmatized drug, sex and HIV risk behaviors on a moderate number of questions. Moreover, a large majority of participants who used A-CASI would like to be assigned to this method of data collection in future interviews.

The survey of the incidence of chromosome mosaicism and pseudomosaicism detected in prenatal diagnosis included data from approximately 60 000 genetic amniocenteses in the United States. There were 59 participating cytogenetic laboratories nationwide. The overall incidence of chromosome mosaicism was 0.25 per cent (range of 0-0.89 per cent). The average frequency of pseudomosaicism involving multiple cells or clones was 0.7 per cent (range of 0-11.21 per cent). The frequency of single cell or clone pseudomosaicism was 2.47 per cent (range of 0-11.49 per cent). In cases of pseudomosaicism with trisomy, the most frequently involved chromosome was number 2; occurrence rates of trisomies 7,X,9,17 and 20 were also relatively high. In cases of pseudomosaicism with structural abnormalities, this survey showed an association between relative chromosome size and the frequency of involvement in structural rearrangement. Data on a total of 185 cases of chromosome mosaicism collected in this survey as well as from other documented sources showed 89 cases involved an autosome, 73 cases a sex chromosome, and 23 a marker chromosome. The frequency of noticeable phenotypic abnormalities was highest (37.8 per cent) in the autosomal mosaics and lowest (10.5 per cent) in the sex chromosome mosaics. The average rate for cytogenetic confirmation was 70 per cent.

The large-scale expansion of syringe exchange was temporally associated with large reductions in both HIV and HCV prevalence. The prevalence and incidence of HCV, however, still remain at high levels among IDU in New York City.

The very large HIV epidemic among drug users in New York City appears to be entering a new phase, in which sexual transmission is of increasing importance. Additional prevention programs are needed to address this transition.

Cohort studies of young (aged 18-30 years) injecting drug users recruited in 1997-1999 in the Harlem and Lower East Side areas of New York City, New York, were used to assess the incidence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). The authors found that HIV incidence was low at both sites: 0.8/100 person-years at the Harlem site and 0/100 person-years at the Lower East Side site. In contrast, HBV incidence was moderate (12.2/100 person-years) at the Harlem site and high (30.7/100 person-years) at the Lower East Side site. Similarly, HCV incidence was moderate (9.3/100 person-years) at the Harlem site and high (34.0/100 person-years) at the Lower East Side site. Results show that high rates of HBV and HCV transmission do not imply high rates of HIV transmission, even within an area of high HIV seroprevalence.

STARHS testing of samples from large serial cross-sectional surveys can provide important data for the assessment of community-level HIV prevention.

One hundred and three cases with prenatal diagnosis of trisomy 20 mosaicism through amniocentesis were reviewed. Approximately 90 per cent (90/101) of the cases were associated with grossly normal phenotype. It is likely that, in the majority of cases, cells with trisomy 20 were extraembryonic in origin or largely confined to the placenta. However, in some cases, the cells with trisomy 20 were confined to certain specific fetal organs or tissues such as kidney, skin, etc. Cytogenetic follow-up studies in liveborns should include a culture from urine sediment.