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Biomedical subjects

C R Horsburgh

Publications and source records attributed to C R Horsburgh.

At least 19 recordsLinked to original sources
PubMed1992

Effects of disease stage and zidovudine therapy on the detection of human immunodeficiency virus type 1 in semen.

OBJECTIVE: To determine the prevalence and temporal expression of infectious human immunodeficiency virus type 1 (HIV-1) in the semen of HIV-1 seropositive men and to determine whether the detection of HIV-1 in semen is associated with disease stage, zidovudine treatment status, or other clinical factors. DESIGN: A microculture technique was used to detect infectious HIV-1 in semen from a cohort of 95 seropositive men. In addition, semen cultures were performed monthly for at least 6 months for 14 of the men. Information was obtained by interview and extracted from medical records to identify clinical variables associated with HIV-1 in semen. PATIENTS: Sixty HIV-1 seropositive homosexual men participating in clinical studies at the Fenway Community Health Center, Boston, Mass, and 35 HIV seropositive bisexual or heterosexual men participating in the California Partner Study of the University of California, San Francisco. MAIN OUTCOME MEASURES: Semen HIV-1 culture results, seminal leukocyte counts, Centers for Disease Control (CDC) disease stage, peripheral CD4+ cell counts, zidovudine therapy, HIV risk category. RESULTS: In the cross-sectional study, HIV-1 was cultured from the semen of nine (9%) of 95 men. Factors associated with detection of HIV-1 in semen were peripheral CD4+ cell counts of 0.20 x 10(9)/L (200/microL) or less (adjusted odds ratio [OR], 23.33; 95% confidence interval [Cl], 2.89 to 175.63); symptomatic (CDC class IV) disease (adjusted OR, 6.56; 95% Cl, 1.02 to 66.76); and seminal leukocytosis (greater than 1 x 10(9) white blood cells per liter of semen) (adjusted OR, 7.02; 95% Cl, 1.28 to 39.29). Zidovudine therapy was associated with decreased detection of HIV-1 in semen (adjusted OR, 0.04; 95% Cl, 0.00 to 0.63). In the longitudinal study of 14 men who had neither peripheral CD4+ cells counts of 0.20 x 10(9)/L or less nor seminal leukocytosis, seminal HIV-1 was detected in at least one sample from six men (43%). CONCLUSION: HIV-1 is more commonly found in semen from men with advanced HIV-1 infection and seminal leukocytosis but can also be cultured from semen of men with neither of these conditions. Zidovudine therapy may decrease the prevalence and/or titer of seminal HIV-1. However, all HIV-1-infected persons should continue to assume that they are potentially infectious through sexual contact.

CD4-Positive T-Lymphocytes↗
PubMed1992

The relation between nitrite inhalants, unprotected receptive anal intercourse, and the risk of human immunodeficiency virus infection.

The role of nitrite was evaluated between 1985 and 1988 in a study of sexual transmission of the human immunodeficiency virus (HIV) among homosexual male couples in Boston, Massachusetts. Initial enrollment data suggested that a history of unprotected receptive anal intercourse (odds ratio (OR) = 2.3, 95% confidence interval (CI) 1.4-3.6) and a history of nitrite use (OR = 1.7, 95% CI 1.1-2.5) were independent risk factors for HIV infection. In addition, interaction between nitrite use and unprotected receptive anal intercourse was observed (OR = 5.5, 95% CI 2.8-11.1) after controlling for number of unprotected receptive anal sex partners and history of sexually transmitted diseases. Since it was felt that nitrite use might be a marker for unprotected receptive anal sexual activity, a supplemental questionnaire was administered to obtain information on simultaneous nitrite use and unprotected receptive anal intercourse. The supplemental data suggested a strong interaction between nitrite use and unprotected receptive anal intercourse in increasing the risk of HIV infection. In the adjusted analyses, the odds ratio for HIV infection was considerably greater among men who always used nitrites during unprotected receptive anal intercourse (OR = 31.8, 95% CI 12.9-76.7) compared with men who sometimes (OR = 7.1, 95% CI 2.1-23.6) or never (OR = 9.0, 95% CI 2.5-32.1) used them. These findings have preventive public health implications and may add insight into our understanding of the mechanism by which HIV infection spread rapidly among homosexual men in the early 1980s.

Adult↗
PubMed1992

Corroboration of sexual histories among male homosexual couples.

Using data from a study of human immunodeficiency virus transmission among homosexual male partners from Boston, Massachusetts, the authors compared self-reported sexual histories among 155 index-partner pairs during 1985-1988. Overall, high levels of agreement were observed for all reported sexual activities. Agreement on anal sex was very high (Spearman's r = 0.78-0.79, p less than or equal to 0.001; kappa = 0.76-0.88, p less than or equal to 0.001). Level of agreement did vary significantly by a couple's drug and alcohol use; the heavier substance user generally reported fewer sexual encounters than the lighter user. These results have important implications in sexual behavior research and show that among homosexual men, self-reports of sexual behavior may be reasonably valid.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Disseminated Mycobacterium avium complex infection: clinical identification and epidemiologic trends.

To evaluate the incidence of disseminated Mycobacterium avium complex infection (DMAC) and to define the association between signs and symptoms and development of DMAC in patients with human immunodeficiency virus (HIV) infection, all cases of DMAC at Grady Memorial Hospital Infectious Disease Clinic (Atlanta) between 1985 and 1990 were reviewed, and a prospective study of the association of symptoms with DMAC was done. Between 1985 and 1990, DMAC occurred in 16% of patients with AIDS. Incidence increased from 5.7% in 1985-1988 to 23.3% in 1989-1990 (P less than .001). Median time from AIDS diagnosis to diagnosis of DMAC increased from 4.5 months in 1985-1988 to 8 months in 1989-1990 (P less than .02). In the prospective study, DMAC was seen only in persons with a CD4+ count less than 100 cells/mm3 and was associated with fever (P less than .03), anemia (P less than .001), weight loss (P less than .01), diarrhea (P less than .01), and elevated alkaline phosphatase (P less than .01). It is recommended that all such HIV-infected persons have mycobacterial blood cultures done.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Changes in the spectrum of AIDS-defining conditions and decrease in CD4+ lymphocyte counts at AIDS manifestation in Germany from 1986 to 1991.

OBJECTIVES: Analysis of changes in the spectrum of AIDS-defining conditions and their correlation with CD4+ lymphocyte counts in different risk groups associated with HIV transmission. METHODS: Review of data from all adult AIDS cases reported in Germany between 1986 and 1991. RESULTS: Among AIDS cases diagnosed between 1986 and 1991, the proportion of cases with lymphoma and wasting syndrome increased, while the proportion of Kaposi's sarcoma decreased. Homosexual men, but not intravenous drug users, showed a decrease in the proportion of cases in Pneumocystis carinii pneumonia and an increase in the proportions with toxoplasmosis and cytomegalovirus infection. The median CD4+ lymphocyte count at time of AIDS diagnosis decreased from 73 x 10(6)/l in 1986 (25 and 75 percentiles, 28 and 212) to 47 x 10(6)/l in 1990 (25 and 75 percentiles, 20 and 120; P less than 0.01). This decrease was the result of reduced CD4+ lymphocyte counts of individuals presenting with opportunistic infections; there was no corresponding change for individuals with non-infectious AIDS-defining conditions. CONCLUSIONS: AIDS diagnosis is now occurring at a later time in the natural history of HIV infection than in 1986, and the relative frequency of specific AIDS-defining conditions has changed. Most pronounced is a decrease of Pneumocystis carinii pneumonia. Changes in the natural history of HIV infection due to therapeutic and prophylactic interventions must be considered when interpreting epidemiological data in the course of the AIDS epidemic. These changes also have implications for the planning and execution of medical care.

Acquired Immunodeficiency Syndrome↗
PubMed1992

A comparison of HIV-1 antibody classes, titers, and specificities in paired semen and blood samples from HIV-1 seropositive men.

Twenty-eight paired blood and semen samples obtained from human immunodeficiency virus type 1 (HIV-1) seropositive men at various stages of disease progression were evaluated for titer and immunoglobulin (Ig) class by an enzyme-linked immunosorbent assay (ELISA). Blood antibody titers ranged from 40,000 to 4,000,000 with a median of 40,000. Semen titers ranged from 400 to 40,000 with a median of 400. HIV-1 antibody titers in matched semen and blood samples showed a strong positive correlation (r = 0.963). The ratio of semen:blood titers ranged from 1:1000 to 1:10 with a median of 1:100. There was no correlation between blood or semen antibody titer and stage of disease of the patients. However, there was a trend toward higher (greater than or equal to 4000) semen antibody titers in men with evidence of genital tract inflammation greater than 10(6) white blood cells/ml semen; 3/5 versus 5/23, p greater than 0.1 Fisher exact test). All HIV-1 antibodies detected were of the IgG class; no IgA or IgM class antibodies of titers greater than or equal to 40 were found in either blood or semen. Thirteen paired blood and semen samples from individual patients were analyzed for antibody specificity by Western blot. In some cases antibody profiles in semen were different from those in blood; strong antibody reactivity against the gp160 viral coat antigen band was consistently detected in semen and blood, whereas the prevalence of detectable antibody reactivity against the p55 and p17 HIV-1 antigen bands was significantly reduced in semen.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody Specificity↗
PubMed1991

Human T lymphotropic virus type II (HTLV-II) infection in a cohort of New York intravenous drug users: an old infection?

To identify risk factors for human T lymphotropic virus type II (HTLV-II) infection in intravenous drug users (IVDUs), participants in a longitudinal study of human immunodeficiency virus (HIV) infection in a New York methadone maintenance program were studied. Of 270 participants tested for HTLV-I/II, 21 (8%) were seropositive. Of those, 15 (71%) had HTLV-II-specific sequences by polymerase chain reaction (PCR) and 1 (5%) had both HTLV-I- and -II-specific sequences; 3 persons with indeterminate serologic results were also PCR-positive for HTLV-II. HTLV-II infection was significantly associated with older age but was not predicted by sex, race, socioeconomic status, transfusion history, or HIV infection status. Behavioral factors since 1978, such as duration and frequency of intravenous drug use, needle sharing, visits to shooting galleries, or number of sex partners, were also not associated with HTLV-II infection. These findings are in contrast with the association of these risk factors with HIV in this group and suggest that, among IVDUs, HTLV-II is an older endemic infection that is less efficiently transmitted than HIV.

Adult↗
PubMed1991

Survival of patients with acquired immune deficiency syndrome and disseminated Mycobacterium avium complex infection with and without antimycobacterial chemotherapy.

The contribution of disseminated Mycobacterium avium complex (DMAC) infection to the morbidity and mortality of patients with acquired immune deficiency syndrome (AIDS) is unclear. Previous studies that suggested the decreased survival of patients with AIDS and DMAC had incomplete information on patient immunologic status and follow-up. We studied patients with AIDS and DMAC and compared their survival with that of AIDS patients without DMAC but with other comparable risk factors for survival. Case and control subjects were similar in terms of CD4 cell count, prior AIDS status, history of antiretroviral therapy, history of Pneumocystis carinii prophylaxis, and year of diagnosis. A group of 39 patients with untreated DMAC had significantly shorter survival, mean of 5.6 +/- 1.1 months (median 4 months), than 39 matched patients with AIDS but without DMAC, mean 10.8 +/- 1.3 months (median 11 months, p less than 0.0001). The survival of 16 additional patients with DMAC who received antimycobacterial therapy, mean of 9.5 +/- 1.4 months (median 8 months), was not significantly shorter than that of an additional 16 matched control subjects, mean 11.7 +/- 1.9 months (median 11 months, p = 0.58). Patients with treated DMAC survived significantly longer than those with untreated DMAC (p less than 0.01). We conclude that untreated DMAC significantly shortens survival. Moreover, these results indicate that patients with DMAC who receive antimycobacterial therapy do not experience the shortened survival seen in untreated DMAC.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Complement levels in patients with hepatic dysfunction.

Total hemolytic complement activity and serum complement protein concentrations were compared in 17 hospitalized patients with normal hepatic function and 16 patients with liver disease due to alcohol (15 patients) or acetaminophen toxicity (one patient). In contrast to the control patients, individuals with hepatic dysfunction had decreased total CH50 levels and low concentrations of total C3, C4, C5, factor B, and the regulatory proteins factor I and beta-1H. These patients also had increased C4d/C4 ratios, indicating classical pathway activation. The level of complement deficiency appears to correlate with either prolongation of the prothrombin time or depression of serum albumin concentration. These results indicate that patients with hepatic disease have severe complement depletion that is probably multifactorial in origin. This impairment in complement function will contribute to the impaired antibacterial host defense of the patient with chronic hepatic disease.

Complement System Proteins↗
PubMed1990

Concordance of polymerase chain reaction with human immunodeficiency virus antibody detection.

To evaluate the correlation of detection of human immunodeficiency virus (HIV) by polymerase chain reaction (PCR) with detection of HIV antibody, 271 simultaneous serum and peripheral blood mononuclear cell samples were examined from 242 persons whose activities placed them at increased risk for HIV infection: 142 from homosexual men, 86 from hemophilic men, and 43 from heterosexual partners of HIV-infected persons. PCR was performed using the gag region primer pair SK38/39 and the env region primer pairs SK68/69 and CO71/72. Amplified HIV DNA was detected using specific oligomer probes. Of 63 HIV antibody-positive samples, 58 (92%) had HIV DNA by PCR. Of 208 HIV antibody-negative samples, 7 (3.4%) had HIV DNA by PCR. On follow-up, 4 of the latter persons were seropositive when next tested; 2 were well and antibody- and PCR-negative; 1 had died of a stroke before retesting. Thus, PCR detects HIV in most antibody-positive persons; detection is increased by use of multiple primer pairs. PCR-positive antibody-negative specimens may indicate HIV infection in which antibody has not yet developed or may be false-positive PCR results. When PCR is discordant with HIV antibody, testing of additional specimens and clinical follow-up are necessary to assess HIV infection status.

Bisexuality↗
PubMed1990

Seroconversion to human immunodeficiency virus in prison inmates.

We evaluated the prevalence and incidence of human immunodeficiency virus (HIV) infection in 3,837 inmates of a state prison system. Ninety-two (2.4 percent) were HIV-seropositive. The highest proportion of HIV-seropositive inmates was found among Blacks (5.4 percent), females, and those 30 years of age or older. HIV-seropositivity of entering inmates was also 2.4 percent and was unchanged over the three years of the study. Seroconversion occurred in two inmates while in prison, a rate of one conversion per 604 person-years, but HIV infection could have occurred before entry. Seroconversion to HIV was rare in inmates in this correctional facility.

Adult↗
PubMed1989

Duration of human immunodeficiency virus infection before detection of antibody.

To estimate the duration and frequency of the period of HIV infection without detectable antibody, modelling techniques were applied to results of detection of HIV DNA by means of the polymerase chain reaction (PCR) and to data from cases in published reports. PCR was carried out with gag and env region primers on samples from 27 homosexual and 12 haemophilic men for whom stored samples were available from before and after seroconversion; serum was also tested for p24 antigen by antigen-capture enzyme immunoassay. HIV DNA was detectable before seroconversion in 4 men; in all 4 PCR was positive only in the seronegative sample taken closest to the time of seroconversion. In 3 men antigen was detected before seroconversion; in each case HIV DNA was also detected. By a Markov model, the time from infection with HIV (as assessed by detection of HIV DNA) to first detection of HIV antibody was estimated to be 2.4 (SE 2.1) months for the median individual. Modelling of cases of HIV infection with known exposure in published reports gave a median estimate of 2.1 (0.1) months from exposure to antibody detection, and 95% of cases would be expected to seroconvert within 5.8 (0.6) months. HIV infection for longer than 6 months without detectable antibody seems uncommon.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Infectiousness of HIV between male homosexual partners.

To estimate the risk of transmission of HIV per receptive anal sexual contact, 329 homosexually-active men, representing 155 sexual partnerships, were enrolled into a study. Information on HIV infection status and sexual behavior within and outside the primary relationship was collected. Of these 329 men, 24 had AIDS and 31 had ARC. Of the 155 couples, 35 consisted of partners that were both HIV +; 62 of partners that were both HIV-; and 58 were discordant. A binomial model was fit to data obtained in the first visit to estimate per contact risk of HIV transmission. Assuming a constant risk of transmission per sexual contact between infected and uninfected partners, the estimated risk is about 5 to 30 per 1000 receptive anal exposures to ejaculate. Although the average risk of HIV transmission per sexual contact appears to be low, there appears to be great variability in infectivity. To model this variability over time and across individuals, more complex models must be fit to longitudinal studies of sexual partners.

AIDS-Related Complex↗
PubMed1989

Increased incidence of infections in intravenous drug users.

To ascertain the incidence of infections in intravenous users of illicit drugs, we performed a retrospective study of 270 intravenous drug users (IVDUs) and 562 controls who did not use drugs over a seven-year period from 1978-1985. IVDUs had an increased overall incidence of infections (P less than 0.001) compared to controls, which was explained to a large degree by an increased incidence of hepatitis. Endocarditis and disseminated gonococcal infection were seen with increased frequency in IVDUs (P less than 0.05), but abscess and cellulitis were not. Neither acquired immunodeficiency syndrome (AIDS), tuberculosis, Pneumocystis pneumonia, nor disseminated viral or fungal infection were seen in IVDUs or controls. Heroin users, but not other IVDUs, had an increased incidence of infections not thought to be associated with needle use, suggesting impaired immunity. This study demonstrates that IVDUs have an increased incidence of infection compared to control subjects, but the kinds of infections have changed substantially over the past two decades. The presence of opportunistic pathogens in these patients should suggest concurrent infection with human immunodeficiency virus (HIV).

Adult↗
PubMed1989

Biologic factors in the sexual transmission of human immunodeficiency virus.

The probability that any single episode of genital-genital or anogenital sexual intercourse will result in transmission of HIV may be determined by multiple biologic factors of the infectious person, the virus itself, and the exposed susceptible person. Some of these factors are known or suspected (figure 1), and they may explain observed differences in the sexual transmission of HIV in different parts of the world, notably in Africa, where genital ulcerative disease is probably influencing the epidemiology of HIV. Several studies have shown that infection in partners of HIV-infected persons is not determined solely by numbers of sexual encounters; on the contrary, HIV-infected partners have usually had fewer sexual encounters with infectious mates than have noninfected partners. Thus, sexually active persons should be cautioned that, to our knowledge, there are no nonsusceptible persons and that any single unprotected sexual encounter may lead to HIV transmission. Research into biologic factors that modulate HIV transmission continues to be hampered by difficulties in identifying HIV transmitters and nontransmitters, infective and noninfective variants of HIV (if the latter exist in vivo), and persons relatively more or less susceptible to HIV infection. However, as the number of partner studies and the number of those enrolled in them increase, a progressively clearer idea of the biologic determinants of sexual transmission of HIV should emerge.

Acquired Immunodeficiency Syndrome↗