Homosexual Volunteers Research Articles

A functional endophenotype for sexual orientation in humans

Sexually arousing visual stimuli activate the human reward system and trigger sexual behavior. Here we performed event-related fMRI during visual processing of sexual core stimuli to pinpoint a neuronal correlate of sexual preference in humans. To dissociate gender of the stimulus from sexual preference, we studied male and female heterosexual and homosexual volunteers while they viewed sexual and nonsexual control stimuli. In contrast to previous work, we used core single-sex stimuli displaying male and female sexually aroused genitals. Since stimuli lacked any additional contextual information, they evoked no activity related to neuronal processing of faces, gestures or social interactions. Our prediction was that the sexual preference of the observer determines the neuronal responsiveness to pure male or female sexual stimuli in the human reward and motor system. Consistent with our prediction, the ventral striatum and the centromedian thalamus, showed a stronger neuronal response to preferred relative to non-preferred stimuli. Likewise, the ventral premotor cortex which is a key structure for imitative (mirror neurons) and tool-related (canonical neurons) actions showed a bilateral sexual preference-specific activation, suggesting that viewing sexually aroused genitals of the preferred sex triggers action representations of sexual behavior. The neuronal response of the ventral striatum, centromedian thalamus and ventral premotor cortex to preferred sexual stimuli was consistent across all groups. We propose that this invariant response pattern in core regions of the human reward and motor system represents a functional endophenotype for sexual orientation independent of the gender of the observer and gender of the stimulus.

Attitudes toward early detection of infection by the AIDS retrovirus among persons at high and low risk

Several months prior to the availability of a now-common blood test, homosexual volunteers, in a longitudinal study of their health, and typical college students were questioned about their attitudes toward early detection of acquired immunodeficiency syndrome (AIDS) and toward receiving information about desirable or fear-worthy hypothetical events. Generally, the homosexual volunteers were more interested in receiving information than were the students. Most homosexual volunteers desired human immunodeficiency virus (HIV) antibody test results, which could indicate infection, and indicated that receiving them would affect their behavior. However, all the subjects showed a preference for information on most questions, especially when the information could be used in guiding behavior change and was not virtually certain to be unfavorable. We are unaware of controlled evidence assessing whether or how knowledge of infection influences the imminent health risk of people who are asymptomatic, but prior to learning their HIV status, the homosexual volunteers who at the time had antibody in their sera were less concerned in knowing the test results of hypothetical future sexual partners than those without antibody.

Neuro-otological Manifestations in Different Stages of HIV Infection

A systematic investigation of the incidence and type of peripheral and central auditory and vestibular disorders occurring in different stages of HIV infection was performed: 43 HIV-seropositive patients (14 were symptomatic with manifestation of AIDS or related complex and 29 were clinically asymptomatic) were compared with a matched control group of 33 HIV-seronegative homosexual volunteers. Among the symptomatic patients 8 (57%) out of 14 and among the asymptomatic HIV-positive patients, 13 (45%) out of 29 had abnormal results in various audiological, vestibular and electrophysiological tests. Only minor anomalies were found in 4 (12%) of the 33 seronegative homosexuals. Our results indicate a high incidence of neuro-otological disorders among patients suffering from AIDS. The numerous electrophysiological abnormalities found in asymptomatic HIV-seropositive persons suggest furthermore an early subclinical involvement of the auditory and vestibular systems.

Coincidence of Deficient Delayed Hypersensitivity and Intestinal Protozoa in Homosexual Men

Stool samples of 134 subjectively and apparently healthy male homosexual volunteers were studied, and in 86 men (64.2%) 190 parasite infestations, up to 6 per host, were identified. The most frequent species were Endolimax nana (40), Entamoeba coli (38), Entamoeba histolytica (34), Entamoeba hartmanni (32), and Iodamoeba bütschlii (22); Cryptosporidium was not found. All 11 isolates of Entamoeba histolytica analysed belonged to a noninvasive zymodeme: 10 were of zymodeme I and I of zymodeme III. In 172 healthy control adults 6 parasite infestations were found. In the homosexual men, a negative tuberculin test was more frequent in the presence than in the absence of parasites. Entamoeba histolytica (p = 0.005) Entamoeba coli (p = 0.013) and Iodamoeba bütschlii (p = 0.004) were associated with the anergy.

Hematologic correlates and the role of erythrocyte CR1 (C3b receptor) in the development of AIDS.

Circulating immune complexes (CICs) are common in patients with the acquired immunodeficiency syndrome (AIDS) as in anemia. In our previous reports, we observed that the deposition of CICs on erythrocytes via C3b receptors (CR1) resulted in a defective CIC clearing system of erythrocytes and in high membrane osmotic fragility of such erythrocytes. We investigated the functional activity of erythrocyte CR1 in 89 patients with AIDS, 41 with AIDS related complex (ARC), 102 healthy homosexual volunteers, and 37 heterosexual males, in relation to the presence of CICs, antibody to lymphadenopathy associated virus/human T lymphotropic virus-III (LAV/HTLV-III), anemia, and the direct and indirect Coombs' tests. CICs were frequently found in all groups except heterosexual males. Absence of CR1 activity was observed in 85% of patients with AIDS, and in 59% with ARC. Impaired CR1 activity also occurred in the homosexual volunteer group. Positive direct Coombs' test and the presence of CICs correlated inversely with CR1 activity while a lowered hematocrit and the presence of antibody to LAV/HTLV-III correlated directly. Neither the sera nor the eluates from erythrocytes with a positive IgG Coombs' test contained IgG antibody against erythrocytes. This suggests decremental loss of CR1 activity progressing from asymptomatic LAV/HTLV-III antibody positive homosexual volunteers to the prodromal spectrum of ARC and finally progressing to a total disappearance in overt AIDS. Of 8 homosexuals volunteers demonstrating the composite of impaired CR1 activity, positive antibody to LAV/HTLV-III, and polyvalent positive direct Coombs' test (with gamma, mu, and C3b), all developed ARC or overt AIDS within 2 years of these observations.

Defective B-lymphocyte function in homosexual men in relation to the acquired immunodeficiency syndrome.

Patients with the acquired immunodeficiency syndrome manifest a wide spectrum of immunologic abnormalities. Polyclonal and antigen-specific differentiation of B lymphocytes into immunoglobulin- and antibody-secreting cells was studied in vitro in three groups of homosexual volunteers: asymptomatic men; men who were symptomatic but lacked clinical criteria for the acquired immunodeficiency syndrome; and those having the syndrome. Although mean responses of all three groups were significantly lower than those of healthy heterosexual male controls, those of the asymptomatic group were least affected. Abnormalities in the symptomatic group were equal to or greater than those of patients with the syndrome, but responses of the latter group were the least augmentable by in vitro manipulations. Severe impairment of B-cell function appeared to favor clinical deterioration. Antibody replenishment might be of value as adjunctive therapy in persons with the acquired immunodeficiency syndrome or as prophylaxis in certain at-risk persons.

Prospective observations of viral and immunologic abnormalities in homosexual males.

This article presents preliminary observations on the immunologic and viral status of 103 homosexual men from New York who were enrolled in a prospective study begun in late 1981. At the time of enrollment, none of the study participants had acquired immunodeficiency syndrome (AIDS) as defined by the Centers for Disease Control (CDC). The initial laboratory investigation indicated that 82.7% of the 1st 81 volunteers had a OKT4:OKT8 ratio lower than the control range of 1.4-2.8. 31 (38.3%) of these 81 volunteers had 1 or more of the following signs and symptoms: history of fever, weight loss, diarrhea, lymphadenopathy, recurrent amebiasis, or persistent amebiasis. As part of the initial study, intensive laboratory investigations were performed on 30 of these subjects, including 20 who were symptomatic. Findings included abnormal T-cell markers, elevated immunoglobulins, circulating immune complexes, and cryoglobulins, as well as B-cell dysfunction. Follow-up of these patients 1 year later indicated that there was no significant improvement in T4:T8 ratio, and those volunteers originally identified as symptomatic continued to contribute the most abnormal ratios. A decrease in the absolute number of T4 lymphocytes contributed most to the ratio reversal. In addition, 26 of the 30 volunteers underwent viral isolation studies from 5 body sites or secretions. 23 of 26 were positive for virus from 1 or more sites compared with 3 of 33 heterosexual controls. Isolation of cytomegalovirus, especially from semen, was most frequent. It remains unclear whether the abnormal immunologic findings in healthy homosexual volunteers represent a transient response to viral infection, an epiphenonomenon due to multifactorial causes that make subjects susceptible to an unidentified AIDS agent, or AIDS itself. The cohort study will continue.