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R Detels

Publications and source records attributed to R Detels.

At least 19 recordsLinked to original sources
PubMed1992

Predictors of the risk of development of acquired immunodeficiency syndrome within 24 months among gay men seropositive for human immunodeficiency virus type 1: a report from the Multicenter AIDS Cohort Study.

The natural history of infection with human immunodeficiency virus type 1 (HIV-1) is characterized by a relentless decline in CD4-positive lymphocytes and the ultimate development of acquired immunodeficiency syndrome (AIDS). However, variables other than the CD4-positive lymphocyte level contribute to the measurement of risk for AIDS and can be used as predictors of AIDS onset. This study was undertaken to identify factors that, independently of the CD4-positive lymphocyte level, would predict the risk of AIDS over 24 months in a cohort of HIV-1 seropositive homosexual men receiving no antiretroviral therapy. Demographic, clinical, and laboratory data from 1,325 white, HIV-1 seropositive participants in the Multicenter AIDS Cohort Study who have been studied for 4 years were analyzed with univariate and multivariate methods. To control for stage of infection, the baseline percentage of CD4-positive lymphocytes (a known marker of disease progression), and the decline of CD4-positive cells during the first 6 months of observation were used as continuous variables. The variables that were independently associated with an increased risk of developing AIDS were: low baseline CD4 percentage, decline in the CD4 percentage during the first 6 months of follow-up, the presence of serum immunoglobulin A at baseline, decrease in hemoglobin during the first 6 months of follow-up, incident fatigue, and the interaction of decline in the CD4 percentage and incident thrush. While low CD4 percentage and other variables have been previously described as prognostic markers, decline in the CD4 percentage and the interaction of that decline and incident thrush have not previously been described as being of prognostic importance. These variables and the analytic method for estimating prognosis may prove useful for selecting and evaluating antiretroviral therapy, instituting prophylactic measures against certain opportunistic infections, and recruitment into clinical trials. Because study participants received no antiretroviral prophylaxis during the period under analysis, the method could be used to estimate the prognosis for those receiving investigational treatment were they to remain untreated, effectively making any participant in a clinical trial his own untreated control.

Acquired Immunodeficiency Syndrome↗
PubMed1992

The effects on survival of early treatment of human immunodeficiency virus infection.

BACKGROUND: Zidovudine has been shown to prolong survival in patients with the acquired immunodeficiency syndrome (AIDS) and, in persons with human immunodeficiency virus (HIV) infection but not AIDS, to delay the progression to AIDS. However, it is still uncertain whether treatment before the development of AIDS prolongs survival. METHODS: We analyzed data from a cohort of 2162 high-risk men who were already seropositive for HIV type 1 (HIV-1) and 406 men who seroconverted from October 1986 through April 1991. There were 306 deaths. The probabilities of death were compared among men at similar stages of disease who began zidovudine therapy before the diagnosis of AIDS and among those who did not. Relative risks of death were calculated for each of five initial disease states on the basis of CD4+ cell counts and clinical symptoms and signs appearing over follow-up periods of 6, 12, 18, and 24 months. Adjustments were also made for the use of prophylaxis against Pneumocystis carinii pneumonia (PCP). RESULTS: After we controlled for CD4+ cell count and symptoms, the use of zidovudine with or without PCP prophylaxis before the development of AIDS significantly reduced mortality in all follow-up periods. The relative risks of death were 0.43 (95 percent confidence interval, 0.23 to 0.78) at 6 months, 0.54 (95 percent confidence interval, 0.38 to 0.78) at 12 months, 0.59 (95 percent confidence interval, 0.44 to 0.79) at 18 months, and 0.67 (95 percent confidence interval, 0.52 to 0.86) at 24 months. After we adjusted for the effects of PCP prophylaxis, zidovudine alone significantly reduced mortality at 6, 12, and 18 months (relative risks, 0.45, 0.59, and 0.70, respectively), but not at 24 months (relative risk, 0.81). Among zidovudine users, those who also used PCP prophylaxis before the development of AIDS had significantly lower mortality at 18 and 24 months than those who did not (relative risks, 0.62 and 0.60, respectively). CONCLUSIONS: The results of this study support the hypothesis that in HIV-1 infection, early treatment with zidovudine and PCP prophylaxis improves survival in addition to slowing the progression to AIDS.

CD4-Positive T-Lymphocytes↗
PubMed1992

The significance of western blot assays indeterminate for antibody to HIV in a cohort of homosexual/bisexual men. The Multicenter AIDS Cohort Study.

The objective of this study was to determine the frequency and significance of nondiagnostic Western blot (WB) assays in homosexual/bisexual men at risk of infection with HIV-1. The presence of a positive enzyme-linked antibody assay (EIA) confirmed by a positive WB was used as evidence of infection and seroconversion. Indeterminate WB assays were defined as reactions to only one viral gene product of HIV-1. Three analyses were conducted to (a) determine the frequency of such reactions in men who, during a 4-year period, did not develop diagnostic serologic reactions; (b) determine, retrospectively, the preseroconversion frequency of indeterminate WB assays in 286 men who seroconverted; and (c) evaluate in vitro production of specific antibody by peripheral blood mononuclear cells (PBMCs) as a method of indicating whether or not an indeterminate WB assay represents HIV-1 infection. Reactions to products of gag, pol, or env were noted in 8.0, 4.0, and 6.7% of 1,595 first-visit tests of men who remained seronegative for 4 years. Indeterminate reactions occurred in 204 men with negative EIAs who subsequently seroconverted and in 82 men with positive EIAs preconversion. Supernatants harvested from PBMCs of 2 of 36 seroconverters obtained one or two visits preseroconversion and cultured with pokeweed mitogen were antibody-positive. All were positive at the visit, with diagnostic serology. None of the supernatants from cells of 19 men with EIA-negative WB-indeterminate serologic assays were antibody-positive. Our results suggest that persistently EIA-negative homosexual/bisexual men who have indeterminate WB assays are unlikely to be infected with HIV-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Bisexuality↗
PubMed1979

The need for epidemiologists.

The increasing need for epidemiologists in biomedical research has been studied by polling organizations with present and potential needs for epidemiologic services. The research institutes of the National Institutes of the National Institutes of Health and the schools of medicine reported the greatest estimated need among the respondents. They and others polled indicated a substantial need for master's and doctoral level epidemiologists that cannot be fulfilled by current training programs in epidemiology. Broad, sound methodological training applicable to all health problems, and increased funding for support of epidemiologic trainees and training programs in institutions, which would make epidemiology training competitive with that in other fields, are strongly recommened.

Epidemiology↗
PubMed1979

The UCLA population studies of chronic obstructive respiratory disease. I. Methodology and comparison of lung function in areas of high and low pollution.

The prevalence of symptoms of chronic obstructive respiratory disease and of functional respiratory impairment was determined in 3465 residents (70 per cent of enumerated) of an area historically exposed to photochemical/oxidant pollutants and 4509 residents (79 per cent of enumerated) of an area exposed to low levels of chemical pollutants. Tests administered included the NHLI questionnaire, electronic volume spirometry, whole body plethysmography, and the single-breath nitrogen test (deltaN2750-1250 and closing volume). Cough and cough with sputum were more frequently reported in the low-pollution area. Lung function was better among residents of the low-pollution area according to FEV1, FVC, maximal expiratory flow rates, closing volume fraction, thoracic gas volume, and airway resistance. Maximal mid-expiratory flow rate, considered to be a sensitive spirometric test for detection of small airways disease, was similar in residents of both areas. Mean deltaN2750-1250 was slightly worse among residents of the low-pollution area. Findings suggest that adverse effects of long-term exposure to photochemical/oxidant pollutants may occur primarily in the larger airways both among smokers and never smokers. The greatest differences between areas were observed in residents 18-59 years of age, suggesting that long-term exposure may be required to cause measurable impairment and that these differnces may be obliterated by such factors as smoking, differential out-migration and differential survival.

Adolescent↗
PubMed1979

Genetic susceptibility to multiple sclerosis.

Previous studies of histocompatibility (HLA) types in multiple sclerosis (MS) families did not provide convincing proof of an HLA-linked susceptibility factor. In 12 families we studied, all MS cases in each family shared at least one chromosome. The probability of this occurring in the absence of genetic linkage is approximately 0.001. The estimated penetrance is 5 percent, implying that the genetic susceptibility factor may be a necessary but not a sufficient cause of MS. Additional studies are needed to identify other differences between affected and unaffected susceptible individuals.

Female↗
PubMed1979

HLA types and immunity in multiple sclerosis.

HLA types and levels of humoral and cell-mediated immune responses to several antigens were studied in a large group of patients with multiple sclerosis, and in controls. Patients were more likely than controls to have the DRw2 antigen. They had higher mean antibody titers to measles but not to cytomegalovirus, herpes 1, or herpes 2, and had less competent cell-mediated responses. Antibody titers to measles were lower and cell-mediated immune responses were more effective in patients with the DRw2 antigen in patients than in patients without it. This apparent specificity for measles suggests that the etiology of multiple sclerosis is related to the immune response to measles or related viruses.

Antibodies, Viral↗
PubMed1979

Multiple sclerosis and housedogs: a case-control study.

A case-control study was conducted to examine the possible association between ownership of housedogs early in life and later development of multiple sclerosis (MS). Sixty MS patients were compared with 60 neighborhood controls matched for age, sex, and race. There was no significant difference between cases and matched controls in housedog ownership, duration of ownership, or age at first exposure to housedogs over the interval from birth to 19 years of age.

Adolescent↗
PubMed1977

Evidence for lower susceptibility to multiple sclerosis in Japanese-Americans.

A search for cases of multiple sclerosis (MS) was carried out among the 120,066 Japanese-American residents and the 3,060,366 Caucasian residents native to state of residence in King and Pierce Counties, Washington, and Los Angeles County, California. Although 48 cases would have been expected among Japanese-Americans in both areas (on the basis of the prevalence among Caucasians in these two areas), only eight cases were found who were residents on prevalence day -- all were American-born residents of Los Angeles County. The age-, sex-adjusted prevalence of MS among Japanese-Americans in both areas was 5.9 per 100,000. The lower prevalence of multiple sclerosis among Japanese-Americans than among Caucasians has been interpreted as evidence of a lower susceptibility to factors causing multiple sclerosis.

Humans↗
PubMed1977

Latitude, migration, and the prevalence of multiple sclerosis.

Prevalence of multiple sclerosis (MS) was determined in three groups of Caucasians in King and Pierce Counties (Washington) and in Los Angeles County (California): natives (born in study state), migrants from high-risk states (North), and migrants from low risk states (South). A diagnosis of definite or probable MS (excluding migrants with onset before migration) was established in 1816 of the persons found. The prevalence in Los Angeles County natives and in migrants from the South to either Los Angeles County or King-Pierce Counties were relatively low, while prevalence in King-Pierce Counties among natives and migrants from the North were high. The prevalence in migrants from the North to Los Angeles was intermediate. The results suggest that some degree of protection is provided to migrants by residence in low-prevalence areas, either early or later in life.

California↗
PubMed1977

Early detection of chronic obstructive pulmonary disease using radionuclide lung-imaging procedures.

One hundred subjects answered a respiratory questionnaire and underwent a physical examination, tests of pulmonary function, and three radionuclide lung-imaging procedures. The results of the radionuclide procedures were compared with each other and with pulmonary function tests and other diagnostic findings to determine their relative sensitivity for detecting evidence of early obstructive airway disease. Perfusion lung imaging was less sensitive than most of the other diagnostic tests evaluated. The aerosol and xenon lung-imaging procedures revealed abnormalities with approximately the same frequency as each other, but more often than any one group of pulmonary function tests, including spirometric data, maximal expiratory flow-volume curves, alveolararterial oxygen gradient, or indices derived from single-breath nitrogen washout. We concluded that xenon and aerosol lung-imaging studies are sensitive and useful screening procedures for detecting evidence of early localized obstructive airway disease and for locating regional abnormalities in the airways of patients with respiratory disease.

Adolescent↗