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Biomedical subjects

B Visscher

Publications and source records attributed to B Visscher.

At least 19 recordsLinked to original sources
PubMed2003

Response to systemic HIV viral load suppression correlates with psychomotor speed performance.

The authors evaluated the association of a virologic response to highly active antiretroviral therapy, or a subsequent rebound, with performance on two measures of psychomotor speed in HIV-positive subjects. Virologic suppression was associated with improved performance on measures of psychomotor speed, and virologic rebound was associated with psychomotor speed performance decline. Changes in plasma HIV viral load in HIV-positive individuals with cognitive slowing correlate with performance on tests of psychomotor speed.

AIDS Dementia Complex↗
PubMed2003

Do STD clinics correctly diagnose STDs? An assessment of STD management in Hefei, China.

The main purposes of the study were to assess the accuracy of laboratory testing and the diagnosis by physicians in sexually transmitted disease (STD) clinics in Hefei, China. Among 347 men complaining of urethral discharge or dysuria, 240 tested positive at the National Centre for either Neisseria gonorrhoeae or Chlamydia trachomatis, 310 tested positive according to the clinic laboratories, and 347 were diagnosed by the physicians. For chlamydia, the sensitivity and positive predictive value (PPV) of the clinic laboratories were 55% and 26%, and for the diagnosis by the physicians were 61% and 24%. Laboratory testing and the diagnosis by the physicians had low power to detect mixed infection. The PPVs for the diagnosis by the physicians were 50% for syphilis and 43% for herpes simplex virus (HSV), indicating that both syphilis and HSV were over-diagnosed. Over half of those previously infected had not received education to prevent reinfection. Thus, the quality of clinic laboratory testing was not high and physicians often misdiagnosed STDs.

Adolescent↗
PubMed1997

Effect of smoking on the clinical progression of HIV-1 infection.

Cigarette smoking as a risk factor in progression of HIV-1 disease was investigated in the Multicenter AIDS Cohort Study of homosexual men. Longitudinal data for T-cell subsets, HIV-related clinical symptoms, smoking behavior, and AIDS medication use were collected semiannually from 2,499 HIV-1-seropositive men for up to 9 years. Survival methods, including Kaplan-Meier analysis and multivariate Cox regression models, were used to assess the effect of cigarette smoking on development of Pneumocystis carinii pneumonia (PCP), AIDS, death, and self-reported oral thrush. After adjustment for CD4+ lymphocyte count and use of antiretroviral and anti-PCP medications, smoking was not significantly associated with progression to PCP, AIDS, or death in either the HIV-seroprevalent or-seroincident cohort members. Among men who had baseline CD4+ cell counts > 200/microliter, smoking was associated with a 40% increase in the hazard of oral thrush (p < or = 0.01). These data indicate that cigarette smoking does not have a major effect on the progression of HIV-1 infection to AIDS or death but may affect the incidence of oral thrush.

Candidiasis, Oral↗
PubMed1995

Predictors for failure of Pneumocystis carinii pneumonia prophylaxis. Multicenter AIDS Cohort Study.

OBJECTIVE: To identify clinical and epidemiological factors associated with failure of Pneumocystis carinii pneumonia (PCP) prophylaxis in those receiving primary and secondary prophylaxis. DESIGN: Longitudinal cohort study of participants infected with human immunodeficiency virus type 1 in the Multicenter AIDS Cohort Study who used PCP prophylaxis regimens after their T-helper lymphocyte counts had decreased to less than 0.200 x 10(9)/L (200/microL). MAIN OUTCOME MEASURE: Occurrence or recurrence of PCP. RESULTS: A total of 476 participants reported taking one or more of the following regimens: trimethoprim-sulfamethoxazole (TMP-SMX), dapsone, and/or aerosolized pentamidine--367 as primary prophylaxis and 109 as secondary prophylaxis after a previous episode of PCP. A total of 92 (20%) developed PCP despite prophylaxis. The mean failure rates per person-year of follow-up were 16.0% for those receiving primary prophylaxis and 12.1% for those receiving secondary prophylaxis (P = .19). Median times to death after initiation of primary or secondary prophylaxis were 2.0 and 1.2 years, respectively. The main predictor for failure of PCP prophylaxis was profound T-helper lymphocytopenia; 86% of failures occurred after T-helper cell counts decreased to less than 0.075 x 10(9)/L and 76% occurred after counts decreased to less than 0.050 x 10(9)/L. In multivariate time-dependent analysis, when compared with counts between 0.100 x 10(9)/L and 0.200 x 10(9)/L, the risk ratio for failure with counts less than 0.050 x 10(9)/L was 2.90 (P < .001). Once T-helper cell counts were considered, fever was the only other health status indicator that predicted subsequent PCP (ie, a time-dependent risk ratio of 2.22; P = .01). Use of TMP-SMX as the prophylaxis regimen was protective but did not eliminate failure (ie, a time-dependent risk ratio of 0.55; P = .03). CONCLUSIONS: These findings strongly support identifying improved methods of PCP prophylaxis once T-helper cell counts decrease to less than 0.075 x 10(9)/L or 0.100 x 10(9)/L. Given this severe degree of immunosuppression, an inherently more effective regimen against P carinii is required.

AIDS-Related Opportunistic Infections↗
PubMed1995

CD4+ T-cell number at the time of acquired immunodeficiency syndrome.

In this article, the authors adapt and extend the methodology of Phillips (Phillips et al. J Acquir Immune Defic Syndr 1992;5:148-52) to estimate the distribution of CD4+ T-cell number at the time of acquired immunodeficiency syndrome (AIDS) and to estimate the correlation between CD4+ T-cell number at AIDS and CD4+ T-cell number prior to human immunodeficiency virus infection. Using data from the Los Angeles portion of the Multicenter AIDS Cohort Study, the authors find that the median CD4+ T-cell count at the time of AIDS is 67 cells/mm3 with a 95% confidence interval of 58-84. The 5th and 95th percentiles of the distribution are 8 and 284, respectively. The authors estimate the correlation between the CD4+ T-cell number at the time of AIDS and the CD4+ T-cell number prior to human immunodeficiency virus infection to be 0.71 with a 95% confidence interval of 0.21-0.94. This very high correlation is suggestive of biologic hypotheses concerning possible control of the circulating CD4+ T-cell number. The high correlation can also be useful in determining when to start prophylactic treatment.

Acquired Immunodeficiency Syndrome↗
PubMed1995

An epidemiologic analysis of Mycobacterium avium complex disease in homosexual men infected with human immunodeficiency virus type 1.

Cofactors associated with the Mycobacterium avium complex (MAC) disease and its prognosis in incident cases of AIDS in homosexuals were studied. We compared 51 men in whom MAC disease developed as the initial AIDS-defining illness (termed AIDS illness hereafter); 157 men who had MAC disease subsequent to another AIDS illness; and 884 men who had only non-MAC AIDS illnesses. MAC disease was the initially diagnosed AIDS illness more often in Baltimore (6.9%) and Los Angeles (5.6%) than in Chicago (2.6%) and Pittsburgh (0) (P < .01). MAC disease also was a more common subsequent AIDS illness in Baltimore (14.3%) and Los Angeles (22.4%) than in Chicago (8.5%) and Pittsburgh (6.5%) (P < .0001). Prophylaxis for Pneumocystis carinii infection increased the occurrence of MAC disease as the initial AIDS illness (from 2.3% to 12.5%; P < .0001). A low white blood cell (WBC) count was slightly more predictive of MAC disease than was a low CD4+ cell count. At 0-6, 7-12, and 13-18 months before diagnosis, the WBC cell counts of 75.0%, 61.1%, and 50.0%, respectively, of those with MAC disease as the initial AIDS illness were < or = 3,400/microL. Men in whom cytomegalovirus disease developed were at higher risk for subsequent MAC disease (relative hazard = 2.65; P < .0001). MAC disease also increased the risk for subsequent cytomegalovirus disease (relative hazard = 3.96; P < .0001).

AIDS-Related Opportunistic Infections↗
PubMed1994

Electroencephalographic coherence in acquired immune deficiency syndrome.

We studied a quantitative electroencephalographic (EEG) measure, coherence, in 28 patients with acquired immune deficiency syndrome (AIDS) and 56 uninfected volunteers. Compared with uninfected subjects, AIDS patients had increased coherence in the 6- to 10-Hz band. The largest increases in coherence were between frontal and occipital regions and between temporal and frontal regions. Coherence within contiguous regions was less affected. Eight of the 28 AIDS patients (29%) had clinically abnormal EEG findings, compared with four of the 56 uninfected control subjects (7%). Among the AIDS patients, 12 had normal neuropsychological performance, nine had mild impairment, and six had moderate impairment. Coherence was increased in each subgroup of AIDS patients, including those with normal neuropsychologic performance and/or normal clinical EEG results. AIDS patients were then classified by quantitative EEG power in frontal head regions as "abnormal" (the upper third of patients) or "normal" (the remainder). Increased coherence was found among both groups. Because the development of abnormal neuropsychological performance or a clinically abnormal EEG examination indicates relatively advanced central nervous system disease, alterations in specific coherence measures may detect subclinical effects of the human immunodeficiency virus on brain function before other changes are evident.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Repeated bereavement, depressed mood, and immune parameters in HIV seropositive and seronegative gay men.

The relationships among bereavement, depressed mood, and immunologic patterns prognostic for the development of acquired immunodeficiency syndrome (AIDS) were determined in a sample of human immunodeficiency virus (HIV) seropositive gay men and a comparison group of HIV seronegative gay men. Immunologic parameters were assessed in 45 men who had recently experienced the deaths of close friends and 45 matched nonbereaved men. No immune differences were found between bereaved and nonbereaved men. Among the HIV seropositive nonbereaved men, higher depressed mood was significantly associated with fewer CD4 (helper/inducer) T lymphocytes, more activated CD8 (suppressor/cytotoxic) T cells, and lower proliferative responses to the mitogen phytohemagglutinin. In summary, HIV seropositive men who reported higher levels of depressed mood not associated with bereavement demonstrated immunologic patterns consistent with HIV activity and progression.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Composite risk score for Kaposi's sarcoma based on a case-control and longitudinal study in the Multicenter AIDS Cohort Study (MACS) population.

The possibility that an agent in addition to human immunodeficiency virus type 1 may be involved in the etiology of Kaposi's sarcoma in acquired immunodeficiency syndrome (AIDS) patients was investigated between 1984 and 1992 in this nested case-control analysis from the Multicenter AIDS Cohort Study (MACS) of homosexual and bisexual men. A total of 316 cases of Kaposi's sarcoma were identified and compared with 510 participants with AIDS and no evidence of cancer. More of the Kaposi's sarcoma cases were from Los Angeles and used a higher number of recreational drugs. The Kaposi's sarcoma cases were also more active sexually. There was a dose-response relation between Kaposi's sarcoma and the number of sexual partners, with an odds ratio of 2 between the most and least sexually active subgroups. The odds ratio for Kaposi's sarcoma increased to 4.18 (95% confidence interval 1.29-14.1) in the presence of a history of five infections. Hepatitis and gonorrhea contributed the most to this relation. The various observed odds ratios did not change after multivariate adjustment for the other risk factors. A model was developed combining all predictive associations into a composite risk score ranging from one to 12 and based on history of infections, sexual activity, use of poppers/nitrites, and having had sexual partners from the West Coast of the United States. The subgroup with the highest scores, compared to the subgroup with the lowest score, had an odds ratio of 8.93 (95% confidence interval 3.21-30.44) for Kaposi's sarcoma. A longitudinal proportional hazards analysis among all 2,190 human immunodeficiency virus type 1-seroprevalent men at study entry, based on this risk score and CD4 cells at baseline, confirmed these findings. Identifying these specific subgroups that are at high and low risk for Kaposi's sarcoma will help future investigations to be more focused in their search for an additional etiologic factor for Kaposi's sarcoma in AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Signs and symptoms of "asymptomatic" HIV-1 infection in homosexual men. Multicenter AIDS Cohort Study.

We investigated the long-term health effects of HIV-1 infection in homosexual men not close to developing AIDS by comparing 916 HIV-1-seropositive (SP) men at least 1.67-3.67 years prior to a clinical AIDS diagnosis to 2,161 HIV-1-seronegative (SN) controls. The SP group reported a higher total of 12 distinct symptoms (fatigue, shortness of breath, night sweats, rash, cough, diarrhea, headache, thrush, skin discoloration, fever, weight loss, and sore throat/mouth) than did the SN group (p < 0.0001), corresponding to at least 5.6 more days/year of such symptoms. The SP group had lower body mass index (p < 0.0001) and lower hemoglobin (p < 0.0001). The SP group was more depressed, as measured by CES-D score (p = 0.047), before knowledge of one's serostatus was likely, and became even further depressed (p = 0.038 for increase in depression) after the HIV-1 serostatus test was accessible to high-risk groups. These associations remained unchanged in multivariate models, incorporating other covariates.

Analysis of Variance↗
PubMed1992

The progression of untreated HIV-1 infection prior to AIDS.

Using a case-control study of untreated men, we investigated the physical, mental, and economic effects of human immunodeficiency virus (HIV-1) infection prior to the diagnosis of acquired immunodeficiency syndrome (AIDS). Beginning 2 to 2.5 years prior to AIDS, case subjects reported more of 12 HIV-1 related symptoms and during the year prior to AIDS, at least 30.6 extra days of these symptoms than did control subjects. Within the 6 months preceding AIDS, case subjects' unemployment rose to 9% (P < or = .05) and depression to 34.2% (P < or = .001). At 6 to 12 months and within 6 months before AIDS, 17.1% and 31.5%, respectively, were anemic, while 37.7% and 64.7% had CD4+ counts less than 200 x 10(6)/L. Diagnosing AIDS at CD4+ counts less than 200 x 10(6)/L could significantly reduce pre-AIDS morbidity. Other implications of these findings are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Hand preference in homosexual men.

The present study examined the distribution of hand preference and its relationship to immune system functioning and performance on neuropsychological tests in a sample of 993 homosexual men from the Multicenter AIDS Cohort Study comprising 502 HIV-1 seronegatives, 436 asymptomatic HIV-1 seropositives, and 55 men with diagnoses of AIDS or AIDS Related Complex. The prevalence of left-handedness in all of the groups (13.1-14.5%) was consistent with prior published reports of prevalent left-handedness in the general population. The distribution of hand preference scores (on a 5-item self-report questionnaire) was J-shaped and shifted to the right as in the general population. There were no differences between right- and left-handers in the immune system parameter of CD4 counts, nor was there any increase of self-reported allergies among the left-handers. We found a significantly larger number of 'outliers' on the neuropsychological measures for left-handers than for right-handers, both for HIV-1 seronegatives and seropositives. These results failed to replicate Lindesay's (1987) report of a leftward shift in manual preference among homosexual men, and failed to support Geschwind and Galaburda's (1985b) hypothesis of a link between homosexuality, handedness and autoimmune disorder. The differences between right- and left-handers on neuropsychological measures, independent of HIV-1 serostatus, are discussed in terms of Satz's (1972) model of pathological left-handedness.

Adult↗
PubMed1991

Epidemiologic patterns of upper respiratory illness and Pneumocystis carinii pneumonia in homosexual men.

The relationship between self-reported upper respiratory illness symptoms (URI) and human immunodeficiency virus Type 1 (HIV-1) was examined in homosexual men using semiannual visits from 1984 to 1988. Temporal and geographic patterns of Pneumocystis carinii pneumonia (PCP) diagnosis in these men during the same time period are also described. URI, including acute sinusitis, was reported more often by 916 HIV-1-seropositive participants than by 2,161 seronegative participants (32.21 versus 28.86% p less than 0.001). For 387 seropositive subjects who progressed to acquired immunodeficiency syndrome (AIDS), the proportion reporting URI peaked one visit pre-AIDS at a level significantly higher than matched control subjects (0.45 versus 0.28, p less than or equal to 0.001). The peak was higher for those with PCP as an initial diagnosis. Reported URI peaked in winter and troughed in summer, and PCP diagnosis rates peaked and troughed 4 months later, respectively. Cities with the highest reported rates of URI also had the highest proportions of AIDS cases with PCP as an initial diagnosis. No temporal or geographic patterns were observed for other HIV-1-related symptoms or non-PCP AIDS diagnoses. These patterns suggest the possibility of a person-to-person transmission of P. carinii similar to that of other respiratory pathogens, which would imply a need to consider stricter methods to prevent nosocomial transmission of this pathogen in inpatient and outpatient settings. Further investigation of these issues is needed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Computerized and conventional neuropsychological assessment of HIV-1-infected homosexual men.

We administered a battery of computerized and conventional neuropsychological measures to a group of 507 HIV-1 seronegative, 439 asymptomatic HIV-1 seropositive (Centers for Disease Control [CDC] groups 2 and 3), and 47 symptomatic HIV-1 seropositive (CDC group 4) homosexual/bisexual men enrolled in the Los Angeles center of the Multicenter AIDS Cohort Study. Tasks included multiple measures of attention, reaction time, memory, and psychomotor speed. Comparison of group means revealed significant differences in performance between HIV-1 seronegative and symptomatic HIV-1 seropositive men on computerized measures of choice reaction time and on conventional measures of memory and motor speed. These findings are consistent with previous research in this area and support the sensitivity of both computerized and conventional neuropsychological instruments for detecting cognitive changes found in symptomatic HIV-1-infected individuals. Asymptomatic seropositive men, on the other hand, did not differ significantly from seronegative subjects on any of the computerized or conventional neuropsychological measures. Only 13% of the asymptomatic HIV-1 seropositive men showed abnormal performance on a composite measure of cognitive functioning from the computerized test battery. This proportion did not differ significantly from that of seronegative controls (14%), but was significantly lower than the percentage of abnormal findings observed among symptomatic HIV-1 seropositive subjects (28%). Thus, results from this study support the hypothesis that the frequency of neuropsychological abnormalities in asymptomatic HIV-1-infected homosexual men is low and not statistically different from that of seronegative controls.

Adult↗
PubMed1991

Normative data for a brief neuropsychological screening battery. Multicenter AIDS Cohort Study.

This study reports normative data for a group of 733 homosexual/bisexual men stratified by age (range 25 to 54 years) and by education on the following six neuropsychological tests: (1) Digit Span (WAIS-R), (2) Rey Auditory Verbal Learning Test, (3) Symbol Digit Modalities Test, (4) Controlled Oral Word Association Test, (5) Grooved Pegboard, and (6) The Trail Making Test. Analysis demonstrates that both age and education are important determinants of performance for several of these measures.

AIDS Dementia Complex↗
PubMed1990

Neuropsychological performance in HIV-1-infected homosexual men: The Multicenter AIDS Cohort Study (MACS)

We administered a battery of standardized neuropsychological measures to assess cognitive functions in a group of 769 HIV-1 seronegative, 727 asymptomatic HIV-1 seropositive (CDC Groups 2 and 3), and 84 symptomatic HIV-1 seropositive (CDC Group 4) homosexual/bisexual men enrolled in the Multicenter AIDS Cohort Study (MACS). Measures included tests of attention, memory, and psychomotor speed. Comparison of group means revealed significant differences in performance between HIV-1 seronegative and symptomatic HIV-1 seropositive subjects on measures of memory and on measures with strong motor and psychomotor timed components. These findings support the sensitivity of these neuropsychological instruments for detecting cognitive changes that may be related to HIV-1, and are consistent with other reports of neuropsychological abnormalities in symptomatic HIV-1-infected individuals. Asymptomatic seropositive men, on the other hand, did not differ significantly from seronegative subjects on any of the neuropsychological measures. Only 5.5% of the asymptomatic HIV-1 seropositive men showed abnormal performance on individual tests. This proportion did not differ significantly from that of seronegative controls. Further, among asymptomatic seropositive subjects, we found no statistically significant differences as a function of duration of HIV infection or level of immune system functioning. Thus, results from this study support the hypothesis that the frequency of neuropsychological abnormalities in asymptomatic HIV-1-infected homosexual men is low, and not statistically different from that of seronegative controls.

Adult↗
PubMed1990

Association of hepatitis B surface antigen and core antibody with acquisition and manifestations of human immunodeficiency virus type 1 (HIV-1) infection.

We examined the associations between seropositivity for hepatitis B virus (HBV) with the presence or development of antibodies to human immunodeficiency virus (HIV-1) and with HIV-1 induced T-helper lymphocyte deficiency or acquired immunodeficiency syndrome (AIDS). Serologic data on HBV and HIV-1, cytometric enumeration of CD4+ lymphocytes, clinical events (AIDS by Centers for Disease Control criteria) and hepatitis B vaccination histories were available on 4,498 homosexual participants in the Multicenter AIDS Cohort Study, Men were classified as to previous infection with HBV and prevalent or incident infection with HIV-1. Although there was an association between seropositivity for HBV infection and HIV-1 infection at enrollment (odds ratios anti-HBc 2.6; HBsAg 4.2), the relation between HBV seropositivity and subsequent seroconversion to HIV-1 was weaker (odds ratios 1.3 and 1.6). HIV-1 seroconversion was also associated with a history of certain other sexually transmitted diseases, but predisposing sexual practices did not account for the association between HBV and HIV-1 infection. Seropositivity for HBV infection at entry was not related to initially low or more rapid subsequent decline in T-helper lymphocyte counts and was not associated with an increased incidence of AIDS during 2.5 years of follow-up. History of vaccination against HBV did not appear to decrease susceptibility to HIV-1 infection or to subsequent progression of immunodeficiency. We conclude that prior HBV infection is unlikely to be specifically associated with acquisition of HIV-1 infection and is unrelated to more rapid progression of HIV-1-induced immunodeficiency.

Acquired Immunodeficiency Syndrome↗