Chromosomal polymorphisms of 1, 9, 16, and Y in 4 major ethnic groups: a large prenatal study.

Using trypsin Giemsa banding (GTG), major polymorphisms of the constitutive heterochromatin regions of chromosome 1, 9, 16, and Y were recorded in a New York City population. Polymorphisms were recorded from amniotic fluid specimens received from 6,250 patients from 4 major population groups, ie, White (European)-2,334 cases, American Black-1,795 cases, Hispanic descent-1,737 cases, and Asian (Oriental and Indian)-384 cases. The major chromosomal polymorphisms were classified as follows: obvious pericentric inversion of the constitutive heterochromatin of the long arm of the chromosome (inv qh); significantly enlarged heterochromatic region of the long arm (qh + is greater than, or equal to, twice the size of the short arm of chromosome 16 [16p]); very small or deficient heterochromatic region in the long arm (qh-); large Y (Yq + greater than size of chromosome 18), small Y (Yq- less than size of a G-group chromosome), and pericentric inversion of Y. Our prenatal study confirmed that the incidence of specific chromosomal variants is different in each population group. The most striking examples of this are the pericentric inversion of chromosome 9 and the different polymorphisms of the Y chromosome. The incidence of inv (9) is highest in the Black population (3.57%); slightly above average in Hispanics (2.42%); and relatively low in Whites (0.73%) and Asians (0.26%). The Y appears to be more variable in Asian (3.37%) and Hispanic (1.82%) than in White or Black groups. The 9qh+ is seen more frequently than 1qh+, or 16qh+. Inv (1), 9qh-, and 16qh- are rare. There were no cases of either 1qh- or inv (16).(ABSTRACT TRUNCATED AT 250 WORDS)

Therapeutic community methods in methadone maintenance (Passages): an open clinical trial.

A non-random open clinical trial was conducted to determine whether a day-treatment program based on modified therapeutic community (TC) methods (Passages) produced better treatment outcomes for heroin addicts than did standard methadone maintenance therapy. Altogether, 327 methadone clients at two clinic sites were studied: 115 Passages members, and 212 comparison subjects. Compared to non-Passages clients, clients who voluntarily joined and remained in Passages for at least 6 months exhibited significantly larger reductions in cocaine use, heroin use, needle use, criminal activity, and psychological dysfunction. The present findings suggest that TC-oriented enhanced day-treatment can help methadone clients recover from drug abuse and adopt a prosocial lifestyle.

United States survey on chromosome mosaicism and pseudomosaicism in prenatal diagnosis.

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.

A revisit of trisomy 20 mosaicism in prenatal diagnosis--an overview of 103 cases.

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.

Amniotic fluid alpha-fetoprotein levels and prenatal diagnosis of autosomal trisomies.

Pregnancies with fetal trisomy 21 have been associated with low amniotic fluid alpha-fetoprotein levels (AFAFP). This observation led to the suggestion that low AFAFP levels be used as a criterion for completion of a chromosomal analysis in patients who are not otherwise at increased risk for a fetal chromosome abnormality and in whom karyotyping might not have been completed for economic reasons. In order to assess the usefulness of such criteria, we reviewed the AFAFP levels of 90 cases of fetal trisomy 21, 23 cases of trisomy 18, and 10 cases of trisomy 13. These were compared with 2400 control samples with normal chromosome constitution. AFAFP levels were generally lower in pregnancies with trisomy 21, showing a median value of 0.72 MoM. However, 40 per cent of the trisomy 21 samples had AFAFP values greater than 0.8 MoM and 20 per cent were over 1.0 MoM. These data imply that over 50 per cent of Down syndrome cases might have been missed using a cut-off level of 0.70 MoM for completion of chromosome analysis. Using a higher cut-off level will leave only a small percentage of samples unkaryotyped. The distribution of AFP levels in trisomy 13 and 18 is no different from controls; we therefore believe that fetal karyotyping should be completed in every amniotic fluid sample obtained.

Trisomy 20 mosaicism in prenatal diagnosis--a review and update.

A total of 66 cases with prenatal diagnosis of trisomy 20 mosaicism was reviewed. Since the majority of cases (85 per cent) was associated with grossly normal phenotype and the abnormalities noted in 15 per cent of cases were inconsistent and rather non-specific, no casual relationship between trisomy 20 mosaicism and a specific malformation syndrome can be established. The possibility of an association between an abnormal phenotype and a high percentage of trisomy 20 cells (greater than 60 per cent) must be considered preliminary and be viewed with caution. The fact that cells with trisomy 20 have not been recovered from blood cultures and were detected more frequently from specific fetal tissues, (such as kidney, rectum, oesophagus), and from placental tissues, suggests that trisomy 20 is more likely to be confined to certain fetal organs and to extra-embryonic tissues. This review calls for the collection of more data on all cases of trisomy 20 mosaicism diagnosed prenatally, in order to provide more accurate information to the prospective parents.

Geographic proximity, policy and utilization of syringe exchange programmes.

The objective of the research was to assess the effects of geographic proximity on the utilization of syringe exchange among injection drug users (IDUs) in New York City. Between 1994 and 1996, 805 IDUs were interviewed with a structured questionnaire. Geographic proximity was defined as living within a ten-minute walk. Eighty-one per cent of IDUs who lived close typically used a syringe exchange compared to 59% of those who lived further away. In multiple logistic regression analysis, those who lived close remained (adjusted odds ratio of 2.89; 95% CI 2.06 to 4.06, p = 0.001) more likely to use syringe exchange. Those who lived close were less likely to have engaged in receptive syringe sharing at last injection (adjusted odds ratio = 0.45, 95% CI 0.24 to 0.86, p = 0.015). In conclusion, locating exchange services in areas convenient to large numbers of IDUs may be critical for prevention of HIV infection.

Similarities and differences by race/ethnicity in changes of HIV seroprevalence and related behaviors among drug injectors in New York City, 1991-1996.

OBJECTIVE: To measure differences and similarities in the prevalence of HIV infection and of related risk and protective behaviors among New York City black, white, and Hispanic drug injectors during a period of decreasing HIV prevalence. METHODS: Drug injectors were interviewed at a drug detoxification clinic and a research storefront in New York City from 1990 to 1996. All subjects had injected drugs within the last six months. Phlebotomy for HIV testing was conducted after pretest counseling. Analysis compares the first half (period) of this recruitment interval with the second half. RESULTS: HIV seroprevalence declined among each racial/ethnic group. In each period, white drug injectors were significantly less likely to be infected than either blacks or Hispanics. Similar declines were found in separate analyses by gender, length of time since first injection, and by recruitment site. After adjustment for changes in sample composition over time, blacks and Hispanics remained significantly more likely to be infected than whites. Interactions indicate that the decline may be greatest among Hispanics and slowest among blacks. A wide variety of risk behaviors declined in each racial/ethnic group; and syringe exchange use increased in each group. Few respondents reported injecting with members of a different racial group at their last injection event. CONCLUSIONS: HIV prevalence and risk behaviors seem to be falling among each racial/ethnic group of drug injectors. Black and Hispanic injectors continue to be more likely to be infected. Declining prevalence among whites poses some risk of politically based decisions to reduce prevention efforts. Overall, these results show that risk reduction can be successful among all racial/ethnic groups of drug injectors and suggest that continued risk reduction programs may be able to attain further declines in infection rates in each group.

Factors associated with prevalent hepatitis C: differences among young adult injection drug users in lower and upper Manhattan, New York City.

OBJECTIVES: This study examined correlates of prevalent hepatitis C virus (HCV) infection among young adult injection drug users in 2 neighborhoods in New York City. METHODS: Injection drug users aged 18 to 29 years were street recruited from the Lower East Side and Harlem. Participants were interviewed about drug use and sex practices; venipuncture was performed for hepatitis B virus (HBV), HCV, and HIV serologies. RESULTS: In both sites, testing positive for HCV antibody (anti-HCV) was associated with having injected for more than 3 years. Additionally, HCV infection was positively associated with injecting with someone known to have had hepatitis (but the association was significant only in the Lower East Side) and with sharing cotton (but the association was statistically significant only in Harlem). Being in drug treatment and older than 24 years were associated with HCV in the Lower East Side but not in Harlem. Receiving money for sex was associated with anti-HCV positivity in Harlem but not in the Lower East Side. CONCLUSIONS: Several differences in factors associated with prevalent HCV infection existed among 2 populations of young injection drug users from the same city. Indirect transmission of HCV may occur.