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Biomedical subjects

W W Darrow

Publications and source records attributed to W W Darrow.

At least 37 records · Page 2Linked to original sources
PubMed1990

Seroprevalence and risk factors for HTLV-I/II infection among female prostitutes in the United States.

We tested 1305 female prostitutes from eight areas of the United States for antibodies to human T-cell lymphotropic virus type I/II. Overall, 6.7% were human T-cell lymphotropic virus type I/II seropositive (with antibodies to both gag and env gene products). The seroprevalence rates ranged from 0% in southern Nevada to 25.4% in Newark, NJ. Human T-cell lymphotropic virus type I/II seropositivity was independently associated with race (odds ratio, 4.68), intravenous drug use (odds ratio, 2.94), hepatitis B seropositivity (odds ratio, 2.87), recruitment in Newark (odds ratio, 2.34), and more years of sexual activity (odds ratio, 1.08 per year of sexual activity). Groups with high rates included blacks, Hispanics, and American Indians, and the rates in these groups were significantly higher than among whites and Asian Americans for women both with and without a history of intravenous drug use. Among intravenous drug users, the only other independent associations were more years of sexual activity and recruitment in Newark; and in non-intravenous drug users, hepatitis B seropositivity. These data show that human T-cell lymphotropic virus type I/II infection is present among female prostitutes in some areas of the United States. Further studies are needed to evaluate patterns of transmission and long-term health effects.

Acquired Immunodeficiency Syndrome↗
PubMed1990

High-risk sexual behavior and knowledge of HIV antibody status in the San Francisco City Clinic Cohort.

To evaluate the effectiveness of human immunodeficiency virus (HIV) testing and counseling among homosexual and bisexual men participating in the San Francisco City Clinic Cohort, compared behavioral data from 181 men who learned their HIV antibody status between 1985 and 1987 with data from 128 men who were tested but declined to receive their results. Overall, significant declines in risk indices for unprotected receptive and insertive anal intercourse occurred between 1983-1984 and 1986-1987, but these declines were independent of both knowledge of HIV status and actual serostatus. Those who chose to learn their HIV status were also no more likely to report depression or to learn their HIV status were also no more likely to report depression or anxiety subsequent to testing. Regression analyses showed no relationship between length of time since learning one's HIV status, mental health symptoms, and the persistence of high-risk behavior in 1986-1987. Although these results do not negate the value of HIV testing and counseling, they suggest that other motivating factors such as frequent access to risk-reduction information may provide sufficient impetus for behavioral change.

AIDS Serodiagnosis↗
PubMed1990

Kaposi's sarcoma in a cohort of homosexual and bisexual men. Epidemiology and analysis for cofactors.

Acquired immunodeficiency syndrome (AIDS) surveillance data for both the United States and San Francisco indicate that Kaposi's sarcoma is more common in homosexual and bisexual men with AIDS than in other adults with AIDS, and that the proportion of newly diagnosed AIDS cases presenting with Kaposi's sarcoma has been significantly declining over time. The changing epidemiology of Kaposi's sarcoma was analyzed in a well-characterized cohort of homosexual and bisexual men; laboratory and interview data from a sample of these men were evaluated for determinants of and cofactors associated with Kaposi's sarcoma. Among 1,341 men with AIDS, the proportion presenting with Kaposi's sarcoma declined from 79% in 1981 to 25% in 1989. Compared with other men with AIDS, men with Kaposi's sarcoma had a shorter interval from human immunodeficiency virus (HIV) seroconversion to AIDS diagnosis (median, 77 vs. 86 months). Men with and without Kaposi's sarcoma did not significantly differ with respect to number of sexual partners, history of certain sexually transmitted or enteric diseases, use of certain recreational drugs (including nitrite inhalants), or participation in certain specific sexual practices. The decline in Kaposi's sarcoma may at least partly be due to a shorter latency period from infection to disease. Although cofactors for the development of Kaposi's sarcoma may exist, many previously hypothesized agents were not supported by this analysis.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Sexual behavior before AIDS: the hepatitis B studies of homosexual and bisexual men.

Data on sexual practices, collected during studies of hepatitis B virus (HBV) infection in 1978 and 1979, were analyzed for 4910 homosexual and bisexual men from Chicago, Denver, Los Angeles, San Francisco, and St Louis. Data on sexual practices in 1978 showed that white participants had larger numbers of non-steady male sexual partners and engaged in oral-genital activities more frequently but were equally likely to engage in anal intercourse as black and Hispanic participants. San Francisco participants had more non-steady sex partners and were more likely to engage in receptive anal intercourse with non-steady partners than participants from all other sites. Analysis of data on 606 HBV-antibody-negative men interviewed on three occasions in 1978 and 1979 showed no changes in risk indices for insertive and receptive anal intercourse between these years, except in San Francisco where significant declines occurred in insertive anal intercourse and receptive anal intercourse without ejacultion in a small, highly select group of participants.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Kaposi's sarcoma among homosexual and bisexual men enrolled in the San Francisco City Clinic Cohort Study.

The changing epidemiology of Kaposi's sarcoma (KS) and possible explanations for this change were analyzed using data from a well-characterized cohort of homosexual and bisexual men. Among 1,341 men with AIDS, the proportion presenting with KS declined from 79% in 1981 to 25% in 1989. For 250 men whose date of HIV seroconversion could be well characterized, persons presenting with KS had a shorter interval from HIV seroconversion to AIDS diagnosis than other AIDS patients without KS (mean = 77 vs. 86 months). Among 182 men who were interviewed prior to a diagnosis of AIDS, men with and without KS did not significantly differ with respect to number of sex partners, a history of certain sexually transmitted or enteric diseases, use of certain recreational drugs (including nitrite inhalants), or participation in certain specific sexual practices. The decline in KS may at least partly be due to a shorter latency period from infection to disease. Although cofactors for the development of KS may exist, many previously hypothesized agents were not supported by this analysis.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Risk of developing AIDS in HIV-infected cohorts of hemophilic and homosexual men.

The latency period and/or incidence of the acquired immunodeficiency syndrome (AIDS) may differ in persons infected with the human immunodeficiency virus by different routes or having different "cofactors." We compared 79 hemophilic men in Pennsylvania and 117 homosexual and bisexual men in California, all having known dates of infection and long postinfection observation periods, to examine these hypotheses. By 1987, twenty-one percent of the hemophilic and 27% of the homosexual men had developed AIDS. However, seroconversion patterns differed for the two groups, and when this was taken into account, the conditional odds ratio for AIDS was 1.20. Kaplan-Meier survival analysis showed no significant difference in the cumulative proportion with AIDS, from time of infection. These results are limited by the small size and geographically localized nature of our study populations, but they suggest that currently the relative length of human immunodeficiency virus infection is of primary importance in comparing disease outcome for different populations.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Statistical analysis of the stages of HIV infection using a Markov model.

We use a staged Markov model to estimate the distribution and mean length of the incubation period for acquired immunodeficiency syndrome (AIDS) from a cohort of 603 human immunodeficiency virus (HIV) infected individuals who have been followed through various stages of infection. The model partitions the infected period into four progressive stages: (1) infected but antibody-negative; (2) antibody-positive but asymptomatic; (3) pre-AIDS symptoms and/or abnormal haematologic indicator; and (4) clinical AIDS. We also model a fifth stage: death due to AIDS. The estimated mean (median) waiting times in each stage of infection are stage 1, 2.2 (1.5) months; stage 2, 52.6 (36.5) months; stage 3, 62.9 (43.6) months; and stage 4, 23.6(16.3) months. We estimate the mean AIDS incubation period (from infection to development of clinical AIDS) as 9.8 years with a 95 per cent confidence interval of [8.4, 11.2] years. The paper also considers the estimated density function of the AIDS incubation period and the estimated survival functions for individuals in each stage of infection. This work represents one of the most complete statistical descriptions to date of the natural history of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Willingness to participate in a national seroprevalence study of HIV infection.

This paper examines the impact of the social dimension of AIDS on a person's willingness to participate in a hypothetical national seroprevalence study of HIV infection. Data from the AIDS supplement of the 1987 National Health Interview Survey provided information about the sociodemographic characteristics and AIDS-related variables and the expressed willingness to participate in a national serosurvey. A multivariate logistic regression model was used to evaluate simultaneously associations between the sociodemographic variables and AIDS-related variables with willingness to participate. Results show that those with sociodemographic characteristics most dissimilar from reported AIDS cases were least willing to participate while those with a high knowledge about AIDS, experience of the HIV test or tested people, and higher perceptions of risk were more willing to participate. We found two exceptions to this general result. First, respondents with no knowledge about AIDS, but a higher level of education, were less willing to participate than those with no knowledge and a lower level of education. Second, respondents with a higher perception of risk and a higher level of education were also less willing than those with high perception of risk and less education.

Acquired Immunodeficiency Syndrome↗
PubMed1988

A model-based estimate of the mean incubation period for AIDS in homosexual men.

Because of the difficulty in identifying the date of exposure to type 1 of the human immunodeficiency virus (HIV-1) infection in persons other than transfusion recipients, studies of the incubation periods for acquired immunodeficiency syndrome (AIDS) have been limited. When data from a cohort of 84 homosexual and bisexual men that provided the information to determine the years of conversion of sera infected with HIV-1 were analyzed, a model for the proportion likely to develop AIDS and the incubation period for AIDS in homosexual men could be derived. The maximum likelihood estimate for the proportion of infected homosexual men developing AIDS is 0.99 (90% confidence interval ranging from 0.38 to 1). Furthermore, the maximum likelihood estimate for the mean incubation period for AIDS in homosexual men is 7.8 years (90% confidence interval ranging from 4.2 years to 15.0 years), which is close to the estimate of 8.2 years for adults developing transfusion-associated AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Estimating AIDS infection rates in the San Francisco cohort.

Between 1978 and 1980 a cohort of approximately 6700 homosexual and bisexual men were recruited from the San Francisco City Clinic to participate in studies of sexually transmitted hepatitis B. Testing frozen blood specimens collected at intervals from these patients provides a means of tracking the spread of the AIDS virus since 1978. The rate of spread of HIV was estimated by fitting different survival curves to interval-censored serological data using maximum likelihood techniques. The curves were compared using the Akaike Information Criterion (AIC) to select that which best describes the data. The best was found to be a log-logistic model, which suggested that between 1978 and 1981 the virus spread rapidly, infecting 44% of the then uninfected cohort members. More recently the rate of spread has declined, with an additional 32% of the cohort becoming infected between 1981 and 1987.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Risk factors for human immunodeficiency virus (HIV) infections in homosexual men.

To clarify risk factors for infection with the human immunodeficiency virus (HIV) we selected at random 785 homosexual men who had participated in studies of hepatitis B in San Francisco in 1978-80 for a follow-up study of the acquired immunodeficiency syndrome. Although most had not been contacted in over five years, 492 (63 per cent) were located and enrolled. The 240 (67 per cent) who had developed antibodies to HIV, as measured by an enzyme-linked immunosorbent assay (ELISA), were compared with 119 who had remained seronegative. In multivariate analyses, receptive anal intercourse with ejaculation by nonsteady sexual partners, many sexual partners per month, and other indicators of high levels of sexual activity were highly associated with seroconversions. None of the sexual practices that we studied appeared to offer protection against HIV infection.

Adult↗
PubMed1986

Sex of interviewer, place of interview, and responses of homosexual men to sensitive questions.

Effects of sex of interviewer and place of interview on the responses of 57 AIDS patients and 145 other homosexual men were studied. Data on sensitive topics were collected by five male and three female medical officers at places convenient to respondents. Male physicians recorded fellatio more frequently, but female physicians recorded younger ages of initiating homosexual activities and more frequent use of certain recreational drugs. These differences apparently were due to different patterns of sexual contact and drug use in four cities. Patients with AIDS tended to be interviewed in hospitals and doctors' offices, other men tended to be interviewed in hotel rooms, and patients tended to be different from other men. After adjustments were made for confounding, sex of interviewer and place of interview seemed to have little influence on the answers obtained.

Acquired Immunodeficiency Syndrome↗
PubMed1985

The epidemiology of AIDS: current status and future prospects.

The reported incidence of acquired immune deficiency syndrome (AIDS) continues to increase in countries throughout the world. On the basis of a polynomial model for extrapolation, the cumulative number of cases diagnosed and reported since 1981 in the United States is expected to double during the next year with over 12,000 additional cases projected to be diagnosed by July 1986. The annual incidence rates for single (never-married) men in Manhattan and San Francisco, intravenous drug users in New York City and New Jersey, and persons with hemophilia A ranged from 261 to 350 per 100,000 population during 1984. For single men aged 25 to 44 years in Manhattan and San Francisco, AIDS was the leading cause of premature mortality in 1984 as measured by years of potential life lost. Infection with HTLV-III/LAV is considerably more common than reported AIDS in high-risk populations and can persist at least for several years, so the presence of specific antibody should be considered presumptive evidence of current infection. The screening of donated blood and plasma for antibody to HTLV-III/LAV and use of safer clotting factor concentrates should greatly reduce HTLV-III/LAV transmission through blood and blood products. Most HTLV-III/LAV infections occur through sexual transmission, use of contaminated needles, and as a result of infected mothers passing the virus to newborns. Continued research commitment is needed to develop an HTLV-III/LAV vaccine and therapy for this infection. In the interim, widespread community efforts are needed to minimize transmission.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Exposure to human T-lymphotropic virus type III/lymphadenopathy-associated virus and immunologic abnormalities in asymptomatic homosexual men.

Immunologic and serologic studies were done in 120 homosexual men who reportedly had no symptoms related to the acquired immunodeficiency syndrome. Forty-nine men (41%) had antibody to the retrovirus human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV), and 37 (31%) had an abnormal T-cell subset ratio and other immunologic abnormalities. These abnormalities were almost exclusively confined to men seropositive for the retrovirus. Multivariate statistical analysis showed that exposure to HTLV-III/LAV was the single best predictor of T-cell (and other) immunologic abnormalities. Sexual practice, particularly receptive anal intercourse, predicted exposure to HTLV-III/LAV but was not independently related to T-cell abnormalities. The association of other microbial serologic findings with HTLV-III/LAV seropositivity or T-cell changes was a coincidental function of sexual activity. Immunologic abnormalities in asymptomatic homosexual men are mostly related to exposure to HTLV-III/LAV.

Antibodies, Viral↗