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PubMed1974

Bisexual mating behavior in a diploid of Saccharomyces cerevisiae: evidence for genetically controlled non-random chromosome loss during vegetative growth.

A diploid strain of Saccharomyces cerevisiae has been isolated which exhabits bisexual mating behavior. The strain mates with either a or alpha strains with a relative mating efficiency of 1 to 2%. The efficiency of mating is correlated with the frequency with which subclones of this strain revert to a single mating type. Crosses of the bisexual diploid with a/a or alpha/alpha diploids yield bisexual segregants with a frequency of approximately 3%. Analysis of the segregation of the mating type alleles and other markers on chromosome III indicates that the primary event which leads to the bisexual phenotype is the loss of one homolog of chromosome III during vegetative growth to produce a monosomic (2n-1) diploid. Evidence is presented that the loss of chromosome III and possibly of other chromosomes during vegetative growth is affected by a recessive nuclear gene-her (hermaphrodite)-which is not closely linked to the mating type locus.

Aneuploidy↗
PubMed1992

A comparison of light intensity preferences for an oviposition site in parthenogenetic and bisexual strains of Drosophila.

On the assumption that the survival of a parthenogenetic strain in nature relies on the strain's ability to compete with the bisexual population, we attempted to discern any diminution of competition between bisexual strains of Drosophila and parthenogenetic strains derived from them on the basis of light intensity preferences in choosing an oviposition site. Four different experiential conditions were imposed on each strain prior to testing for light intensity preferences for an oviposition site. Most light responses are significantly different in each strain for the four experiences. There are also significant differences among the bisexual, unisexual and F1 females of a given strain and between strains. Further experiments were performed to determine light preferences during oviposition when unisexual and bisexual females were in direct competition. In only one comparison were their light preferences significantly different. All strains were unique in their overall behavioral spectra.

Animals↗
PubMed2004

Interaction strategies of lesbian, gay, and bisexual healthcare practitioners in the clinical examination of patients: qualitative study.

OBJECTIVE: To explore how lesbian, gay, and bisexual healthcare practitioners manage their identity in the clinical examination of patients. DESIGN: Qualitative study using grounded theory. SETTING: Hospital and primary health care. PARTICIPANTS: 16 healthcare professionals who identified themselves as lesbian, gay, or bisexual, and are involved in the clinical examination of patients. RESULTS: Healthcare professionals engage in a complex interplay of identity management strategies to avoid homophobic abuse; as a signal of safety from homophobia and understanding for their lesbian, gay, and bisexual patients and as a desexualisation strategy principally for gay men and their women patients. Their training has not helped them deal with ethical and medicolegal anxieties. CONCLUSION: In the light of new legislation, published guidelines will help training and governing bodies understand and help ameliorate the added pressures on their lesbian, gay, and bisexual students and medical staff.

Female↗
PubMed1976

Differential variation of parthenogenetic and bisexual Haemaphysalis longicornis (Acari: Ixodidae).

Morphological characters are measured from each tick specimen from samples of 10 "populations" of Haemaphysalis longicornis. The 10 populations consist of 6 diploid bisexual and 4 triploid parthenogenetic populations from Australia, Japan, and Korea. Statistical analyses (univariate and multivariate) of differential morphological variation are made among sex, method of reproduction, and chromosome ploidy level in attempts to determine the effects of these parameters on overall variation. In general, laboratory-reared thelytokous females (3n = 33y are least variable, laboratory-reared bisexual females and males (2n = 22 female; 21 male) are intermediate in variation, and field-collected bisexual males and females are most variable. However, the only field-collected thelytokous "population" (3n = 33) in the analyses is more variable than even the field-collected bisexual ticks.

Animals↗
PubMed2005

Differential expression of vasa RNA and protein during spermatogenesis and oogenesis in the gibel carp (Carassius auratus gibelio), a bisexually and gynogenetically reproducing vertebrate.

The RNA helicase Vasa is a germ cell marker in animals, and its homolog in vertebrates to date has been limited to bisexual reproduction. We cloned and characterized CagVasa, a Vasa homolog from the gibel carp, a fish that reproduces bisexually or gynogenetically. CagVasa possesses 14 RGG repeats and eight conserved motifs of Vasa proteins. In bisexually reproducing gibel carp, vasa is maternally supplied and its zygotic expression is restricted to gonads. By in situ hybridization on testicular sections, vasa is low in spermatogonia, high in primary spermatocytes, reduced in secondary spermatocytes, but disappears in spermatids and sperm. In contrast, vasa persists throughout oogenesis, displaying low-high-low levels from oogonia over vitellogenic oocytes to maturing oocytes. A rabbit anti-Vasa antibody (alphaVasa) was raised against the N-terminal CagVasa for fluorescent immunohistochemistry. On testicular sections, Vasa is the highest in spermatogonia, reduced in spermatocytes, low in spermatids, and absent in sperm. In the ovary, Vasa is the highest in oogonia but persists throughout oogenesis. Subcellular localization of vasa and its protein changes dynamically during oogenesis. The alphaVasa stains putative primordial germ cells in gibel carp fry. It detects gonadal germ cells also in several other teleosts. Therefore, Cagvasa encodes a Vasa ortholog that is differentially expressed in the testis and ovary. Interestingly, the alphaVasa in combination with a nuclear dye can differentiate critical stages of spermatogenesis and oogenesis in fish. The cross-reactivity and the ability to stain stage-specific germ cells make this antibody a useful tool to identify fish germ cell development and differentiation.

Amino Acid Sequence↗
PubMed1994

Personality and lipid level differences associated with homosexual and bisexual identity in men.

Self-identified homosexual (n = 30), bisexual (n = 29), and heterosexual (n = 31) men were compared on measures of gender-typical behavior, sex role, ego strength, and lipid levels. Homosexual men differed significantly from the heterosexual men on the gender-typical behavior and feminine sex-role measure (both in adulthood and in childhood), and several trends and significant differences were found on the biochemical measures of lipid levels (especially when 7 obese men were removed from the analyses). As a rule, the bisexual men were different from the heterosexual men on the above measures, but were indistinguishable from the homosexual men. Bisexuals differed from both of the other two groups, however, by scoring lower on the ego strength scale and by reporting themselves to be more often troubled, lonely, and depressed. We caution that the lipid analyses were made on single blood samples and require an extended replication; however, we report the data because of their possible theoretical interest and because they replicate work of 20 years ago.

Adult↗
PubMed1995

Is gender dysphoria dysphoric? Elevated depression and anxiety in gender dysphoric and nondysphoric homosexual and bisexual men in an HIV sample. HNRC Group.

Few if any studies before the AIDS epidemic suggested that male homosexuals may on average have higher levels of depression than male heterosexuals. However, several samples of homosexual and bisexual men in HIV studies suggest that depression and anxiety are high in these populations, and that this psychiatric morbidity began before the AIDS epidemic. We tested the hypothesis that high childhood gender nonconformity (CGN) is associated with depression and anxiety, and so might account for differences in these variables among samples of homosexuals. A total of 254 homosexual or bisexual male subjects were assessed for depression, anxiety, and associated symptoms using various self-report and interview measures, as well as for CGN (using the Freund Feminine Gender Identity scale, FGI). For comparison purposes only, we also evaluated the subjects for the DSM-III diagnosis of Ego-Dystonic Homosexuality. Highly gender nonconforming men (high FGI scores) were more likely to have current symptoms of anxiety and depression by self-report, and to have had a lifetime history of depression by clinical interview. This association was more often due to FGI items dealing with childhood than adulthood. When the FGI was broken into subscales by a prior factor analysis, stepwise regression suggested that the subscale measuring core gender identity nonconformity (so-called "gender dysphoria") was more reliably associated with depression and anxiety than were the factors measuring nonconformity in the areas of masculine and feminine gender roles, or genitoerotic (sexual) roles. This subscale was also the only FGI measure correlating with Ego-Dystonic Homosexuality. AIDS (CDC stage and HIV serostatus) and age did not account for these findings. We conclude that the often-reported higher levels of depression, anxiety, and associated symptoms among homosexual and bisexual men in AIDS studies are more common in the subgroup of such men who are gender dysphoric. Theoretical and clinical implications of these data are discussed.

Adult↗
PubMed2005

Cigarette smoking and lesbian and bisexual women in the Bronx.

This study investigated the prevalence of cigarette smoking, smoking patterns, and smoking cessation efforts of Black and Hispanic lesbian and bisexual women from a poor, urban community. One-on-one interviews were conducted with a convenience sample of 130 self-identified Black and Hispanic lesbian and bisexual women from the Bronx, NY. Bivariate statistics were used to determine differences between Black and Hispanic respondents in smoking prevalence, frequency, desire to quit, and impact on family unit. Fifty-five percent of Black respondents and sixty-two percent of Hispanic respondents were current smokers. Hispanics were more likely than Blacks to have a partner (p < 0.04), 2 or more children (p < 0.05), and an asthmatic in their household (p < 0.02). Hispanics were less likely than Blacks to have ever attempted to quit (p < 0.04) and to have made a serious attempt to quit in the past year (p < 0.02). Culturally sensitive interventions are needed to help Hispanic lesbian and bisexual women move from the pre-contemplative to action stage of quitting. The large proportion of current smokers requires greater access to effective smoking cessation tools.

Adolescent↗
PubMed1992

Risk of Kaposi's sarcoma and sexual practices associated with faecal contact in homosexual or bisexual men with AIDS.

The causal agent of Kaposi's sarcoma is unknown. That the disorder is ten times more common in homosexual or bisexual men with the acquired immunodeficiency syndrome (AIDS) than in other human immunodeficiency virus (HIV) transmission groups suggests that a certain aspect of their behaviour exposes them to the agent or facilitates its spread. We therefore assessed social and demographic characteristics, including sexual behaviour, of 65 homosexual or bisexual men with AIDS from London. Sexual practices in which there was contact with partner's faeces before AIDS developed were the main determinants of Kaposi's sarcoma risk. Risk increased with frequency of insertive "rimming" (oral-anal contact): Kaposi's sarcoma developed in 18% of the men with AIDS who reported never having practised insertive rimming compared with 50% who practised it less than once a month, 73% between once a week and once a month, and 75% or more once a week (two-sided exact p-value for trend less than 0.001). 45 men had been interviewed about their sexual practices before AIDS developed, and 20 were interviewed at the time the syndrome developed. The findings were similar and statistically significant when each group was analysed separately. The men with Kaposi's sarcoma also tended to be more sexually active and were more likely to engage in other sexual activities that entailed contact with faeces than were the men who had other features of AIDS only. Other behaviours and exposures, including the use of "poppers" (nitrite inhalants), were not related to Kaposi's sarcoma risk, after taking into account whether the subjects had practised insertive rimming. The data suggest that faecal-oral contact is the main route of transmission of the agent of Kaposi's sarcoma in homosexual or bisexual men with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Lesbian and bisexual women's recommendations for improving the provision of assisted reproductive technology services.

Qualitative focus groups were conducted with lesbian and bisexual women who were themselves or whose partners were in the process of trying to conceive (n = 6); who were biological parents of young children (n = 7); and who were nonbiological parents of young children or whose partners were currently pregnant (n = 10) to explore their donor insemination service needs and to provide recommendations for improved or additional services. The 10 recommendations generated by participants included providing cues that the service is lesbian and bisexual positive; offering lesbian- and bisexual-specific infertility support; providing opportunities for women to make informed choices about use of interventions consistent with their known or presumed fertility; and offering accessible services to known sperm donors, including gay men.

Attitude to Health↗
PubMed2000

Cost-effectiveness of screening for anal squamous intraepithelial lesions and anal cancer in human immunodeficiency virus-negative homosexual and bisexual men.

PURPOSE: Homosexual and bisexual men are at an increased risk for human papillomavirus-induced squamous intraepithelial lesions and cancer of the anus. Our objective was to estimate the cost-effectiveness of screening for anal squamous intraepithelial lesions in these high-risk patients. SUBJECTS AND METHODS: A Markov model was developed to evaluate alternative screening strategies using anal cytology in a hypothetical cohort of homosexual and bisexual men. Data were obtained from prospective cohort studies, national databases, Medicare reimbursement rates, and the published literature. Model outcomes included life expectancy, quality-adjusted life expectancy, total lifetime costs, and incremental cost-effectiveness ratios. RESULTS: The undiscounted life expectancy gain associated with anal cytology screening every 3 years was 5.5 months. Compared with no screening, screening every 3 years increased the discounted quality-adjusted life expectancy by 1.8 months and cost $7,000 per quality-adjusted life year (QALY) gained. Screening every 2 years cost $15,100 per QALY gained compared with screening every 3 years. Annual screening provided incremental benefits of less than 0.5 quality-adjusted months and had an incremental cost of $34,800 per QALY gained. Screening every 6 months provided little additional benefit (i.e, 5 days) over that of annual screening and had an incremental cost of $143,500 per QALY gained. CONCLUSION: In homosexual and bisexual men, screening every 2 or 3 years for anal squamous intraepithelial lesions with anal cytology would provide life-expectancy benefits comparable with other accepted preventive health measures, and would be cost-effective.

Adult↗
PubMedDate not supplied

Sexual HIV risk among gay and bisexual male methamphetamine abusers.

The current report examined HIV-related high risk sexual behaviors among a small sample of gay and bisexual male methamphetamine abusers in Los Angeles. Participants were 16 methamphetamine-abusing or -dependent gay or bisexual males who participated in a treatment demonstration project between 1989 and 1993. All participants completed the NIDA/WAVE survey, a detailed inventory of HIV-related risk behaviors. Findings indicate a strong connection between methamphetamine abuse and high-risk sexual behavior. For the 12 months prior to treatment 62.5% of participants reported having anal insertive sex without a condom, and 56.3% reported having sex with someone who had HIV. Drug use before or during sex, measured on a 5-point Likert scale, was frequent (M = 4.27, SD = 0.7). Implications for treatment of gay and bisexual male methamphetamine abusers and prevention of HIV among this population are discussed.

Behavior Therapy↗
PubMed1998

Post-exposure prophylaxis for HIV infection in gay and bisexual men. Implications for the future of HIV prevention.

OBJECTIVE: To assess the psychological and behavioral characteristics of gay and bisexual men who intend to use antiretroviral post-exposure prophylaxis (PEP) to prevent HIV infection. METHODS: Gay and bisexual men who had not tested HIV seropositive and were not in long-term exclusive sexual relationships (n = 327) completed anonymous surveys consisting of demographic characteristics, gay community acculturation, experience with and attitudes toward PEP, substance use, and sexual behavior in the past 6 months. SETTING: A large annual Gay Pride festival in Atlanta, Georgia. RESULTS: There were 8 (3%) men who had already used PEP and 85 (26%) who planned to use PEP to prevent themselves from becoming HIV infected. Compared to the 242 (74%) men who did not indicate plans to use PEP, those planning to use PEP were younger, less well educated, more likely to have used illicit substances in the past 6 months, and were more likely to have a history of injection drug use. Men intending to use PEP were also more likely to have practiced unprotected anal and oral intercourse as the receptive partner and were more likely to have multiple anal intercourse partners with whom they were receptive. CONCLUSIONS: Gay and bisexual men are generally supportive of the immediate use of PEP and a significant number of men are planning to use PEP, particularly less educated men who use multiple substances and practice the highest-risk sexual behaviors. Concurrent behavioral interventions must, therefore, be considered critical in the advancement of PEP.

Adult↗
PubMed1998

Gender differences in health and risk behaviors among bisexual and homosexual adolescents.

OBJECTIVE: This study explored gender differences in the health and risk behaviors of 394 self-identified bisexual and homosexual adolescents who participated in an anonymous, school-based survey. METHODS: Respondents included 182 girls and 212 boys; girls were significantly younger than boys (p < 0.001), so respondents were further grouped as younger (< or =14 years) and older (> or =15 years) for analysis. Chi-square was used to test for gender differences in health perceptions and risk behaviors. Items included general health perceptions and health care access, body image and disordered eating behaviors, sexual behaviors, alcohol use, and emotional health measures including mood, life satisfaction, and suicidal ideation and attempts. RESULTS: Both younger and older girls were significantly more likely than their male age mates to report a history of sexual abuse, dissatisfaction with weight, a negative body image, more frequent dieting, and an earlier age at onset of sexual intercourse. Both younger and older boys were significantly more likely than girls to have a positive body image, to rate themselves as healthier than peers, to report no regular source of health care, to be sexually experienced, and to drink alcohol more often and in greater quantity; a significantly greater proportion of older boys than older girls reported alcohol use before school (19.0% vs. 3.9%; p < 0.05). No significant gender differences were found for measures of emotional health, including suicidal ideation and attempts; however, nearly 1 of 3 older boys and girls reported at least one suicide attempt. CONCLUSIONS: Gender is a substantive source of variation in health and risk behaviors among bisexual and homosexual adolescents. Health care providers should incorporate gender-specific approaches to health promotion and risk reduction with young people who self-identify as gay, lesbian, or bisexual.

Adolescent↗
PubMed1998

Antecedents and consequences of victimization of lesbian, gay, and bisexual young people: a structural model comparing rural university and urban samples.

Research indicates that antigay victimization is widespread and that lesbian, gay, and bisexual young people may be very vulnerable to such victimization. The current study builds upon previous work by Hershberger and D'Augelli (1995), who studied the consequences of sexual orientation-based victimization in 194 urban lesbian, gay, and bisexual youths. Using structural equation modeling, the present study models both antecedents and consequences (including psychological distress, self-esteem, and suicidality) of victimization via a secondary analysis of their data set. In addition, a second sample of 54 lesbian, gay, and bisexual youths from a rural university setting was examined to cross-validate and generalize the relationships found in urban settings. Results indicated that a revised model of victimization exhibited sufficient fit to the urban sample data and provided preliminary support for the generalizability of the model beyond the initial sample. Additional similarities were found between the urban and rural university community samples, including a high prevalence of reported suicide attempts: 42% of the urban sample and 32% of the rural university sample had attempted suicide at least once. Results indicated that victimization based on sexual orientation has similar correlates for young people in different community settings.

Bisexuality↗
PubMed2004

Changes in the meaning of sexual risk behaviors among gay and bisexual male methamphetamine abusers before and after drug treatment.

Methamphetamine is widely used among gay and bisexual men in the West Coast of the United States, and is often used in combination with high-risk sexual activities. This study combined quantitative and qualitative research methodologies to examine sexual risk behaviors among gay and bisexual male methamphetamine abusers as they entered treatment and at 1-year follow-up evaluations. Findings from the quantitative follow-up data demonstrate that gay and bisexual men reduce sexual risk behaviors and sustain those reductions following substance abuse treatment, and qualitative data reveal the meaning of these behavior changes from the perspective of the participant. At 1-year evaluations, associated behaviors of methamphetamine use and sexual risk behaviors were lessened. Although condom use decreased slightly, participants reported fewer anonymous sexual partners, reductions in episodes of both receptive and insertive anal intercourse, and an increased sense of responsibility to disclose their HIV status. This study further demonstrates the value of coupling quantitative with qualitative data in understanding the meanings behind reductions in high-risk behaviors.

Adult↗
PubMed1994

Verbal and physical abuse as stressors in the lives of lesbian, gay male, and bisexual youths: associations with school problems, running away, substance abuse, prostitution, and suicide.

A common theme identified in empirical studies and clinical reports of lesbian, gay male, and bisexual youths is the chronic stress that is created by the verbal and physical abuse they receive from peers and adults. This article reviews the verbal and physical abuse that threatens the well-being and physical survival of lesbian, gay male, and bisexual youths. This response to gay male, lesbian, and bisexual adolescents by significant others in their environment is often associated with several problematic outcomes, including school-related problems, running away from home, conflict with the law, substance abuse, prostitution, and suicide. Although the causal link between these stressors and outcomes has not been scientifically established, there is suggestive evidence that these outcomes are consequences of verbal and physical harassment.

Adolescent↗
PubMed2003

Prevalence of mental disorders, psychological distress, and mental health services use among lesbian, gay, and bisexual adults in the United States.

Recent estimates of mental health morbidity among adults reporting same-gender sexual partners suggest that lesbians, gay men, and bisexual individuals may experience excess risk for some mental disorders as compared with heterosexual individuals. However, sexual orientation has not been measured directly. Using data from a nationally representative survey of 2,917 midlife adults, the authors examined possible sexual orientation-related differences in morbidity, distress, and mental health services use. Results indicate that gay-bisexual men evidenced higher prevalence of depression, panic attacks, and psychological distress than heterosexual men. Lesbian-bisexual women showed greater prevalence of generalized anxiety disorder than heterosexual women. Services use was more frequent among those of minority sexual orientation. Findings support the existence of sexual orientation differences in patterns of morbidity and treatment use.

Adult↗