Minority Stressors, Social Provisions, and Past-Year Suicidal Ideation and Suicide Attempts in a Sample of Sexual Orientation and Gender Identity/Expression Minority People in Canada

Purpose: Mental health disparities in sexual orientation and/or gender identity and/or expression (SOGIE) minority groups are well-documented, with research consistently showing higher levels of suicidality, even in Canada, considered one of the world's most accepting countries of SOGIE minority groups. Adverse outcomes in these groups are often framed using minority stress theory, with social support frequently studied as an integral buffer to these outcomes. This analysis explores facets of minority stress and social support associated with past-year suicidal ideation and suicide attempts. Methods: A cross-sectional internet survey of SOGIE diverse people in Canada (n = 1542) was conducted. Binary logistic regression calculated bivariate and multivariate factors associated with past-year suicidal ideation and suicide attempts. Backward elimination (retaining sociodemographic factors and self-rated mental health) identified salient minority stress and social support (provisions) factors. Results: Over half (56.72%) of participants had ever thought of dying by suicide, with 24.84% having attempted suicide. During the past year, 26.80% had thought of dying by suicide, with 5.32% having attempted suicide. Victimization events, and guidance (e.g., someone to talk to about important decisions) and attachment (e.g., close relationships providing emotional security) social provision subscales remained salient after backward elimination procedures. Conclusion: Our findings emphasize that a fulsome, multilevel approach considering structural, community, and individual strategies to address overt discrimination, integrating social connections and guidance, is necessary to prevent dying by suicide.

Exploring community enabling factors associated with recent HIV testing in a regional sample of gay, bisexual, and other men who have sex with men

HIV testing and diagnosis are the gateway into treatment and eventual viral suppression. With gay, bisexual, and other men who have sex with men (GBMSM) persistently over-representing new HIV diagnoses in Canada, combined with the evolving nature of community social connection, an exploration of factors associated with recent HIV testing is warranted. As most studies of GBMSM rely on samples obtained from larger metropolitan regions, examining HIV testing from an under-researched region is necessary. With data collected from an online survey of LGBTQ+ persons 16 or older living, working, or residing in the Region of Waterloo, Ontario, Canada, we used multinomial logistic regression to explore socio-demographic, behavioural, and psychosocial factors associated with recent HIV testing for GBMSM. In the final multivariate multinomial logistic regression model: sense of belonging was associated with more recently testing, as was having an increasing proportion of LGBT friends, app use to find sex partners in the past 12 months, access to the local AIDS service organization, and general sense of belonging to local community, among other. This analysis highlights the continued importance of enabling and need factors when accessing testing, and suggests areas for further testing promotion in physical and virtual spaces frequented by GBMSM.

Experiences of trans patients in primary care settings: findings from The OutLook Study

BACKGROUND

Relationships between primary care providers (PCP) and trans patients remain important, necessitating discussions about gender identity, health and their intersections.

METHODS

Using an online survey, we explored socio-demographic and psycho-social factors associated with: (1) disclosing gender identity; (2) discussing gender identity-related health issues; and (3) comfort sharing gender identity with PCPs, among trans people (n=112) over 16years of age, sampled in Waterloo, Ontario, Canada. Bivariate and multivariate methods using modified Poisson regression generated effect estimates.

RESULTS

Age, birth presumed gender, employment status, family support, and transphobia were significantly associated with disclosing gender identity, discussing gender identity-related health issues, and comfortability sharing gender identity with PCPs.

CONCLUSION

Increasing PCPs' knowledge of trans-related health issues is stressed to improve access and quality for trans patients.

Experiences of Transgender Participants in Emergency Departments: Findings from the OutLook Study

Purpose: Even in cases of medical emergency, mistreatment and negative experiences in life or in medical settings can deter trans patients from seeking necessary care. The purpose of this study was to identify factors associated with trans persons' emergency department (ED) avoidance in the mixed urban-rural Region of Waterloo, Ontario, Canada. Methods: The OutLook Study was a community-based partnership that created an online, cross-sectional questionnaire for lesbian, gay, bisexual, transgender, and other sexual and gender minority community members. Participants in this analysis were 16 years of age or older, lived, worked, or attended school in Waterloo Region, and identified as trans (n=112). Binary logistic regression was used to test associations between sociodemographic, resilience, and risk variables, and ED avoidance. Sociodemographic variables statistically significant at p<0.05 at the bivariate level were included as controls to explore different combinations of resilience and risk factor in multivariable models. Results: Participants reporting complete or partially complete medical transitions were more likely to report ED avoidance, compared to those who had not initiated medical transition. Elevated transphobia was associated with greater likelihood of avoidance. However, increasing levels of social support decreased the likelihood of avoidance. In multivariable models, social support, support from a special person, and transphobia were always significant, regardless of controlled variables. Conclusion: Transphobia-enacted in the contexts of everyday life and health care-can deter patients from seeking care. Patient-centered care requires careful attention to trans identity and health needs, especially in emergency settings. In the absence of structural changes, providers can take steps to mitigate the erasure and discrimination trans patients experience and anticipate when accessing EDs.

Community acceptance and HIV sexual risk among gay and bisexual men in a ‘typical’ Canadian city

Included in Statistics Canada's largest geographical “peer group,” London, Ontario is typical of many mid-size Canadian cities. A local health forum identified community acceptance and homophobia as key factors impacting LGBTQ health; we studied these with regard to HIV-related sexual risk in gay and bisexual men. Survey data were collected from 201 gay and bisexual men in Middlesex-London, Ontario; 173 reported their HIV status as negative/unknown and were included in this analysis. Unadjusted and adjusted prevalence risk ratios (PRRs) were modelled using modified Poisson regression. First, a model was fit for non-modifiable sociodemographic and background factors. Community factors were then added: social support; internalized homonegativity; perceptions of community acceptance of people like oneself (based on orientation, racialization, gender identity). Older age was associated with decreased risk; other sociodemographic and background factors were not. For each 10-year increase in age, prevalence of high-risk sex decreased by 24% (PRR=0.76; 95% CI: 0.60, 0.95). Controlling for age, we found an interaction between perception of broader community acceptance and gay community acceptance of people like oneself. As broader community acceptance increased, high-risk sex decreased; however, this effect varied depending upon perceptions of gay community acceptance, with men feeling most accepted within the gay community having the smallest reductions in high-risk sex. This interaction raises a series of questions. Among these: How do community norms and availability of partners shape sexual risk-taking? Are conventional “contextualized” measures of sexual risk sufficient, or do they miss important risk-mitigation strategies used within gay communities?

Sexual Orientation Disclosure in Primary Care Settings by Gay, Bisexual, and Other Men Who Have Sex with Men in a Canadian City

PURPOSE

Sexual orientation affects individuals' health histories and is fundamental to providers' understanding of patients as a whole. Gay, bisexual, and other men who have sex with men (GB-MSM) are vulnerable to certain health conditions, including HIV. The aim of this exploratory analysis was to examine factors associated with sexual orientation disclosure and communication with providers about GB-MSM health issues and to discuss implications.

METHODS

We conducted a cross-sectional internet survey of GB-MSM (n = 202) in London-Middlesex, Ontario, Canada; analyses were limited to those with a regular primary care provider (n = 173). Blockwise regression models explored demographic, psychosocial, and healthcare-related factors associated with sexual orientation disclosure and physician-patient communication about GB-MSM-related health.

RESULTS

Just over seventy-one percent (71.1%) of participants reported that their primary care provider (PCP) knew their sexual orientation, and 44.5% had talked to them about GB-MSM health. Overt negative comments or being refused care based on sexual orientation occurred infrequently, although 26.6% reported their provider had assumed they were heterosexual. Being married to or living common-law with another man, more frequent experiences of homosexual prejudice, and higher quality assessment of provider's communication skills were associated with the PCP knowing respondents' sexual orientation. Greater internalized homonegativity was associated with not talking to a PCP about GB-MSM-related health issues. More frequent experiences of homosexual prejudice, higher assessment of provider communication, and having prior negative experiences with a PCP were significantly associated with talking to a PCP about GB-MSM health.

CONCLUSION

The majority of our sample disclosed their sexual orientation; however, not all patients voluntarily disclose. Medical training and education in Canada, where specific rights protections exist for sexual orientation minority populations, should emphasize awareness of essential patient health information. Training should include information about GB-MSM health and building a foundation on how to speak with GB-MSM patients nonjudgmentally.

Sociodemographic Differences by Survey Mode in a Respondent-Driven Sampling Study of Transgender People in Ontario, Canada

PURPOSE

To describe survey mode uptake and sociodemographic differences by mode among respondents to a respondent-driven sampling survey of transgender people in Ontario, Canada. Survey mode was left to participant choice.

METHODS

Data were collected from 433 transgender Ontarians in 2009-2010 through a self-administered questionnaire, available online, by paper copy, or by telephone with language interpretation.

RESULTS

Paper respondents (9.5%) were significantly more likely to be Aboriginal or persons of color, underhoused, sex workers, and unemployed or receiving disability benefits.

CONCLUSION

In Canada and similar high-income countries, sampling transgender populations that are diverse with respect to social determinants of health may be best carried out with multimode surveys.

A Pilot Trial of a Sexual Health Counseling Intervention for HIV-Positive Gay and Bisexual Men Who Report Anal Sex without Condoms

Background

Even in the presence of promising biomedical treatment as prevention, HIV incidence among men who have sex with men has not always decreased. Counseling interventions, therefore, continue to play an important role in reducing HIV sexual transmission behaviors among gay and bisexual men and other men who have sex with men. The present study evaluated effects of a small-group counseling intervention on psychosocial outcomes and HIV sexual risk behavior.

Method

HIV-positive (HIV+) peer counselors administered seven 2-hour counseling sessions to groups of 5 to 8 HIV+ gay and bisexual men. The intervention employed information provision, motivational interviewing, and behavioral skills building to reduce sexual transmission risk behaviors.

Results

There was a significant reduction in condomless anal sex (CAS) with HIV-negative and unknown HIV-status partners, from 50.0% at baseline to 28.9% of the sample at 3-month follow-up. Findings were robust even when controlling for whether the participant had an undetectable viral load at baseline. Significant reductions were also found in the two secondary psychosocial outcomes, loneliness and sexual compulsivity.

Conclusions

The findings provide preliminary evidence that this intervention may offer an efficient way of concurrently reducing CAS and mental health problems, such as sexual compulsivity and loneliness, for HIV+ gay and bisexual men.

Trial Registration

ClinicalTrials.gov NCT02546271

Sociodemographic Differences by Survey Mode in a Respondent-Driven Sampling Study of Transgender People in Ontario, Canada

PURPOSE

To describe survey mode uptake and sociodemographic differences by mode among respondents to a respondent-driven sampling survey of transgender people in Ontario, Canada. Survey mode was left to participant choice.

METHODS

Data were collected from 433 transgender Ontarians in 2009-2010 through a self-administered questionnaire, available online, by paper copy, or by telephone with language interpretation.

RESULTS

Paper respondents (9.5%) were significantly more likely to be Aboriginal or persons of color, underhoused, sex workers, and unemployed or receiving disability benefits.

CONCLUSION

In Canada and similar high-income countries, sampling transgender populations that are diverse with respect to social determinants of health may be best carried out with multimode surveys.

Community Cleavages: Gay and Bisexual Men's Perceptions of Gay and Mainstream Community Acceptance in the Post-AIDS, Post-Rights Era

Changes in gay and bisexual men's connectedness to the gay community are related to the declining public visibility of HIV/AIDS and greater acceptance for homosexuality and bisexuality in mainstream society. Little work, however, has focused on perceived acceptance for subgroups within the gay community or broader society. Using interviews (n = 20) and a survey (n = 202) of gay and bisexual men in a mid-sized Canadian city, we find perceived hierarchies of acceptance for the various subgroups as well as an age effect wherein middle-aged men perceive the least acceptance for all groups. These differences are linked with the uneven impact of social, political, and institutional changes relevant to gay and bisexual men in Canada.

High heterogeneity of HIV-related sexual risk among transgender people in Ontario, Canada: a province-wide respondent-driven sampling survey

BACKGROUND

Studies of HIV-related risk in trans (transgender, transsexual, or transitioned) people have most often involved urban convenience samples of those on the male-to-female (MTF) spectrum. Studies have detected high prevalences of HIV-related risk behaviours, self-reported HIV, and HIV seropositivity.

METHODS

The Trans PULSE Project conducted a multi-mode survey using respondent-driven sampling to recruit 433 trans people in Ontario, Canada. Weighted estimates were calculated for HIV-related risk behaviours, HIV testing and self-reported HIV, including subgroup estimates for gender spectrum and ethno-racial groups.

RESULTS

Trans people in Ontario report a wide range of sexual behaviours with a full range of partner types. High proportions - 25% of female-to-male (FTM) and 51% of MTF individuals - had not had a sex partner within the past year. Of MTFs, 19% had a past-year high-risk sexual experience, versus 7% of FTMs. The largest behavioural contributors to HIV risk were sexual behaviours some may assume trans people do not engage in: unprotected receptive genital sex for FTMs and insertive genital sex for MTFs. Overall, 46% had never been tested for HIV; lifetime testing was highest in Aboriginal trans people and lowest among non-Aboriginal racialized people. Approximately 15% of both FTM and MTF participants had engaged in sex work or exchange sex and about 2% currently work in the sex trade. Self-report of HIV prevalence was 10 times the estimated baseline prevalence for Ontario. However, given wide confidence intervals and the high proportion of trans people who had never been tested for HIV, estimating the actual prevalence was not possible.

CONCLUSIONS

Results suggest potentially higher than baseline levels of HIV; however low testing rates were observed and self-reported prevalences likely underestimate seroprevalence. Explicit inclusion of trans people in epidemiological surveillance statistics would provide much-needed information on incidence and prevalence. Given the wide range of sexual behaviours and partner types reported, HIV prevention programs and materials should not make assumptions regarding types of behaviours trans people do or do not engage in.

Herpes simplex virus type 2 seropositivity and relationship status among U.S. adults age 20 to 49: a population-based analysis

BACKGROUND

U.S. population studies show herpes simplex virus type 2 (HSV-2) seroprevalence levelling by approximately age 30, suggesting few new infections after that age. It is unclear whether this pattern is driven by greater percentages in stable relationships, and to what extent adults who initiate new relationships may be at risk of incident HSV-2 infection.

METHODS

Survey and laboratory data from the 1999-2008 waves of the U.S. National Health and Nutrition Examination Survey (NHANES) were combined for 12,862 adults age 20-49. Weighted population estimates of self-reported genital herpes, HSV-2 seroprevalence, and past-year sexual history were calculated, stratified by age, sex, race, and relationship status. Multivariable logistic regression was used to assess whether relationship status provided additional information in predicting HSV-2 over age, race and sex, and whether any such associations could be accounted for through differences in lifetime number of sex partners.

RESULTS

Those who were unpartnered had higher HSV-2 prevalence than those who were married/cohabitating. Among unpartnered 45-49 year olds, seroprevalence was 55.3% in women and 25.7% in men. Those who were married/cohabitating were more likely to have had a past-year sex partner, and less likely to have had two or more partners. The effect of age in increasing the odds of HSV-2 was modified by race, with higher HSV-2 prevalence among Black Americans established by age 20-24 years, and the effect of race decreasing from age 30 to 49. Relationship status remained an independent predictor of HSV-2 when controlling for age, race, and sex among those age 30 to 49; married/cohabitating status was protective for HSV-2 in this group (OR = 0.69)

CONCLUSIONS

Whereas sexually transmitted infections are often perceived as issues for young adults and specific high-risk groups, the chronic nature of HSV-2 results in accumulation of prevalence with age, especially among those not in married/cohabitating relationships. Increased odds of HSV-2 with age did not correspond with increases in self-reported genital herpes, which remained low. Adults who initiate new relationships should be aware of HSV-2 in order to better recognize its symptoms and prevent transmission.

Interferon-kappa, a novel type I interferon expressed in human keratinocytes

High throughput cDNA sequencing has led to the identification of interferon-kappa, a novel subclass of type I interferon that displays approximately 30% homology to other family members. Interferon-kappa consists of 207 amino acids, including a 27-amino acid signal peptide and a series of cysteines conserved in type I interferons. The gene encoding interferon-kappa is located on the short arm of chromosome 9 adjacent to the type I interferon gene cluster and is selectively expressed in epidermal keratinocytes. Expression of interferon-kappa is significantly enhanced in keratinocytes upon viral infection, upon exposure to double-stranded RNA, or upon treatment with either interferon-gamma or interferon-beta. Administration of interferon-kappa recombinant protein imparts cellular protection against viral infection in a species-specific manner. Interferon-kappa activates the interferon-stimulated response element signaling pathway and a panel of genes similar to those regulated by other type I interferons including anti-viral mediators and transcriptional regulators. An antibody that neutralizes the type I interferon receptor completely blocks interferon-kappa signaling, demonstrating that interferon-kappa utilizes the same receptor as other type I interferons. Interferon-kappa therefore defines a novel subclass of type I interferon that is expressed in keratinocytes and expands the repertoire of known proteins mediating host defense.

Cloning and expression of human sialic acid pathway genes to generate CMP-sialic acids in insect cells

The addition of sialic acid residues to glycoproteins can affect important protein properties including biological activity and in vivo circulatory half-life. For sialylation to occur, the donor sugar nucleotide cytidine monophospho-sialic acid (CMP-SA) must be generated and enzymatically transferred to an acceptor oligosaccharide. However, examination of insect cells grown in serum-free medium revealed negligible native levels of the most common sialic acid nucleotide, CMP-N-acetylneuraminic acid (CMP-Neu5Ac). To increase substrate levels, the enzymes of the metabolic pathway for CMP-SA synthesis have been engineered into insect cells using the baculovirus expression system. In this study, a human CMP-sialic acid synthase cDNA was identified and found to encode a protein with 94% identity to the murine homologue. The human CMP-sialic acid synthase (Cmp-Sas) is ubiquitously expressed in human cells from multiple tissues. When expressed in insect cells using the baculovirus vector, the encoded protein is functional and localizes to the nucleus as in mammalian cells. In addition, co-expression of Cmp-Sas with the recently cloned sialic acid phosphate synthase with N-acetylmannosamine feeding yields intracellular CMP-Neu5Ac levels 30 times higher than those observed in unsupplemented CHO cells. The absence of any one of these three components abolishes CMP-Neu5Ac production in vivo. However, when N-acetylmannosamine feeding is omitted, the sugar nucleotide form of deaminated Neu5Ac, CMP-2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (CMP-KDN), is produced instead, indicating that alternative sialic acid glycoforms may eventually be possible in insect cells. The human CMP-SAS enzyme is also capable of CMP-N-glycolylneuraminic acid (CMP-Neu5Gc) synthesis when provided with the proper substrate. Engineering the CMP-SA metabolic pathway may be beneficial in various cell lines in which CMP-Neu5Ac production limits sialylation of glycoproteins or other glycans.

Neuroserpin reduces cerebral infarct volume and protects neurons from ischemia-induced apoptosis

Neuroserpin, a recently identified inhibitor of tissue-type plasminogen activator (tPA), is primarily localized to neurons within the central nervous system, where it is thought to regulate tPA activity. In the present study neuroserpin expression and its potential therapeutic benefits were examined in a rat model of stroke. Neuroserpin expression increased in neurons surrounding the ischemic core (ischemic penumbra) within 6 hours of occlusion of the middle cerebral artery and remained elevated during the first week after the ischemic insult. Injection of neuroserpin directly into the brain immediately after infarct reduced stroke volume by 64% at 72 hours compared with control animals. In untreated animals both tPA and urokinase-type plasminogen activator (uPA) activity was significantly increased within the region of infarct by 6 hours after reperfusion. Activity of tPA then decreased to control levels by 72 hours, whereas uPA activity continued to rise and was dramatically increased by 72 hours. Both tPA and uPA activity were significantly reduced in neuroserpin-treated animals. Immunohistochemical staining of basement membrane laminin with a monoclonal antibody directed toward a cryptic epitope suggested that proteolysis of the basement membrane occurred as early as 10 minutes after reperfusion and that intracerebral administration of neuroserpin significantly reduced this proteolysis. Neuroserpin also decreased apoptotic cell counts in the ischemic penumbra by more than 50%. Thus, neuroserpin may be a naturally occurring neuroprotective proteinase inhibitor, whose therapeutic administration decreases stroke volume most likely by inhibiting proteinase activity and subsequent apoptosis associated with focal cerebral ischemia/reperfusion. (Blood. 2000;96:569-576)

Cervical dentin hypersensitivity. Part II: Associations with abfractive lesions

OBJECTIVE

The purpose of this retrospective study was to evaluate the association between cervical dentin hypersensitivity and the presence of abfractive lesions.

METHOD AND MATERIALS

Written records and study casts for 250 active-care patients, selected alphabetically, were analyzed for the clinical detection of abfractive lesions and cervical dentin hypersensitivity from 1979 until 1996. Clinical diagnosis of abfractive lesions was made according to existing literature descriptions of these hard tissue lesions. Cervical dentin hypersensitivity was diagnosed when a verified positive threshold patient response was found during tooth evaluation by the air indexing method. Patient groups I and II were formed solely on the basis of the presence or absence, respectively, of a verified positive threshold patient response of cervical dentin to air.

RESULTS

A significant association was found between air-indexed cervical hypersensitivity and the presence of abfractive lesions. The primary locations for both cervical hypersensitivity and abfractive lesions were the buccal surfaces of posterior teeth.

CONCLUSION

This long-term retrospective study found a positive association between cervical dentin hypersensitivity and abfractive lesions. The correlative nature of this study suggests the need for further investigation.

Cervical dentin hypersensitivity. Part I: The air indexing method

The purpose of this article is to introduce an objective method for quantifying cervical dentin hypersensitivity. Air emissions from a standard air-water syringe or a syringe with a Fluid Control Block are directed toward the cervices of teeth at a 45-degree angle to the long axis of test teeth from a distance of 0.5 cm for 0.5 to 1.0 second. An air indexing method has been developed to quantify threshold patient response values for individual teeth to this defined air stimulus. The air indexing method, using the Fluid Control Block, offers the clinician objective information to compare cervical dentin hypersensitivity before and after treatment for this common, painful condition.

Cloning and expression of the human N-acetylneuraminic acid phosphate synthase gene with 2-keto-3-deoxy-D-glycero- D-galacto-nononic acid biosynthetic ability

Sialic acids participate in many important biological recognition events, yet eukaryotic sialic acid biosynthetic genes are not well characterized. In this study, we have identified a novel human gene based on homology to the Escherichia coli sialic acid synthase gene (neuB). The human gene is ubiquitously expressed and encodes a 40-kDa enzyme. The gene partially restores sialic acid synthase activity in a neuB-negative mutant of E. coli and results in N-acetylneuraminic acid (Neu5Ac) and 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (KDN) production in insect cells upon recombinant baculovirus infection. In vitro the human enzyme uses N-acetylmannosamine 6-phosphate and mannose 6-phosphate as substrates to generate phosphorylated forms of Neu5Ac and KDN, respectively, but exhibits much higher activity toward the Neu5Ac phosphate product.

Efficacy of keratinocyte growth factor-2 in dextran sulfate sodium-induced murine colitis

The purpose of this study was to determine the efficacy of a novel human protein, keratinocyte growth factor-2 (KGF-2), in a model of murine colitis induced by ad libitum exposure to a 4% solution of dextran sulfate sodium (DSS) in the drinking water. Initial evaluation of KGF-2 was based on its ability to reduce weight loss, stool score, and histological score in mice exposed to DSS for 7 days. When KGF-2 (0.1-10.0 mg/kg i.p. or s.c.) was injected daily into DSS-treated mice from day 0 to 7, it significantly reduced all three parameters in a dose-response fashion, with a minimum effective dose of between 1 and 3 mg/kg. When KGF-2 was given therapeutically, starting 4 days after initiation of the 7-day DSS treatment, the 3- but not the 0.5-mg/kg dose significantly enhanced weight recovery after discontinuation of DSS treatment. When DSS treatment was prolonged beyond the normal 7 days, therapeutic intervention on day 2 or 4 also significantly reduced mortality, weight loss, and stool score at the 1- and 3-mg/kg dose. Therapeutic treatment also resulted in reduction of colon myloperoxidase levels by more than 50%. These experiments suggest that KGF-2 may be clinically useful in the treatment of inflammatory bowel diseases such as ulcerative colitis and Crohn's disease.

Analysis and metaanalysis of two polymorphisms within the tyrosine hydroxylase gene in bipolar and unipolar affective disorders

Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the synthesis of dopamine and noradrenaline. While positive associations between TH and bipolar affective disorder have been found in several studies, many studies have failed to reproduce these results. In order to clarify this situation, association studies of bipolar and unipolar affective disorder groups and metaanalyses of published data on the TH tetranucleotide repeat polymorphism were done. The association studies used the TH tetranucleotide repeat polymorphism in intron 1 and a PstI polymorphism at the 3' end of the gene. The study comprised 124 unrelated bipolar patients, 126 unipolar patients, and 242 controls. There was no significant association of either bipolar or unipolar affective disorder with the TH tetranucleotide repeat polymorphism. However, a weak association (chi2 = 3.946, 1 df, P = 0.047; odds ratio, allele 2 vs. allele 1 = 0.71 (95% CI, 0.51-0.996)) was observed in the unipolar sample with the TH-PstI polymorphism. Three metaanalyses of published data on the TH tetranucleotide repeat polymorphism in major affective disorder were performed: bipolar I + II vs. control using 583 cases and 745 controls; unipolar vs. control using 204 cases and 359 controls; and bipolar + unipolar vs. control using 846 cases and 823 controls. In each analysis there was no association of the TH tetranucleotide repeat polymorphism and affective disorder. These results do not support the tyrosine hydroxylase gene having a major role in the etiology of bipolar affective disorder. However, our data suggest that this locus should be examined in larger samples of unipolar affective disorder.

No association of a functional polymorphism in the dopamine D2 receptor promoter region with bipolar or unipolar affective disorders

The dopaminergic system, along with the serotonergic and noradrenergic systems, has been implicated in the etiology of mood disorders. An association study of a functional variant in the promoter region of the dopamine D2 receptor (DRD2) with bipolar affective disorder I or unipolar major affective disorders was performed. Variable expression of the DRD2 gene in vitro has been shown with this promoter polymorphism. One hundred and thirty-one unrelated bipolar patients, 128 unrelated unipolar patients, and 262 controls were used in the study. There were no significant differences in DRD2 allele or genotype frequencies between the affective disorder and control groups. These results do not support a major role for the DRD2 gene in the etiology of either bipolar or unipolar affective disorders.

Neuroserpin, a brain-associated inhibitor of tissue plasminogen activator is localized primarily in neurons. Implications for the regulation of motor learning and neuronal survival

A cDNA clone for the serine proteinase inhibitor (serpin), neuroserpin, was isolated from a human whole brain cDNA library, and recombinant protein was expressed in insect cells. The purified protein is an efficient inhibitor of tissue type plasminogen activator (tPA), having an apparent second-order rate constant of 6. 2 x 10(5) M-1 s-1 for the two-chain form. However, unlike other known plasminogen activator inhibitors, neuroserpin is a more effective inactivator of tPA than of urokinase-type plasminogen activator. Neuroserpin also effectively inhibited trypsin and nerve growth factor-gamma but reacted only slowly with plasmin and thrombin. Northern blot analysis showed a 1.8 kilobase messenger RNA expressed predominantly in adult human brain and spinal cord, and immunohistochemical studies of normal mouse tissue detected strong staining primarily in neuronal cells with occasionally positive microglial cells. Staining was most prominent in the ependymal cells of the choroid plexus, Purkinje cells of the cerebellum, select neurons of the hypothalamus and hippocampus, and in the myelinated axons of the commissura. Expression of tPA within these regions is reported to be high and has previously been correlated with both motor learning and neuronal survival. Taken together, these data suggest that neuroserpin is likely to be a critical regulator of tPA activity in the central nervous system, and as such may play an important role in neuronal plasticity and/or maintenance.

A novel regulatory function of proteolytically cleaved VEGF-2 for vascular endothelial and smooth muscle cells

By high throughput sequencing, we have identified a cDNA encoding a polypeptide related to vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF) in the VEGF/PDGF gene family. It is designated vascular endothelial growth factor 2 (VEGF-2). Similar to VEGF, expression of VEGF-2 mRNA is abundant in vascular smooth muscle cells and several highly vascularized tissues. VEGF-2 protein is expressed as a secreted 52 kDa precursor as well as the 30 kDa amino-terminal and 27 kDa carboxy-terminal cleavage products. The latter two cleavage products are linked via a disulfide bridge (or bridges) and can be copurified. Using copurified 30 and 27 kDa proteins, the effect of VEGF-2 on growth of several cell types, including vascular endothelial and smooth muscle cells, was determined. Our results demonstrate that VEGF-2 protein stimulates the growth of human vascular endothelial cells but inhibits growth of human aortic smooth muscle cells induced by platelet-derived growth factor. These studies establish VEGF-2 as a novel regulator for growth of vascular endothelial and smooth muscle cells.

Production and purification of novel secreted human proteins

Our objective during the last year was to produce and purify 50-80 novel, secreted human proteins identified via high throughput cDNA sequencing and computer analysis. We chose the baculovirus expression vector system in order to obtain secreted, correctly folded, bioactive proteins. Recombinant (re-)baculoviruses (BV) were plaque purified, and pulse-labeling was used to verify the synthesis and secretion of the re-proteins. N-terminal microsequencing was performed to simultaneously confirm the identity of the protein(s) as well as the signal peptide (SP) cleavage site(s). Following sequence confirmation, the proteins were purified to homogeneity and functional assays carried out to determine potential therapeutic applications. We identified proteins with antiviral activity, several novel growth factors, proteins influencing the differentiation of specific cell types, novel proteases and protease inhibitors among others. Certain proteins were expressed both in insect cells and in CHO stable cell lines. In the cases analyzed, we found that the same SP cleavage site was utilized in the two expression systems. Significant differences were observed in the carbohydrate moieties attached to the proteins, though no effects on the biological activity due to these differences have been demonstrated. The BV system has served as a viable alternative for the high throughput, high fidelity expression of many novel secreted human genes. To date, more than 75 new genes have been expressed, and the re-proteins purified. This expression system combines many favorable traits including relative speed, moderate cost but perhaps most importantly, the production of biologically active proteins.

Cystatin E is a novel human cysteine proteinase inhibitor with structural resemblance to family 2 cystatins

A new member of the human cystatin superfamily, called cystatin E, has been found by expressed sequence tag (EST) sequencing in amniotic cell and fetal skin epithelial cell cDNA libraries. The sequence of a full-length amniotic cell cDNA clone contained an open reading frame encoding a putative 28-residue signal peptide and a mature protein of 121 amino acids, including four cysteine residues and motifs of importance for the inhibitory activity of Family 2 cystatins like cystatin C. Recombinant cystatin E was produced in a baculovirus expression system and isolated. An antiserum against the recombinant protein could be used for affinity purification of cystatin E from human urine, as confirmed by N-terminal sequencing. The mature recombinant protein processed by insect cells started at amino acid 4 (cystatin C numbering), and displayed reversible inhibition of papain and cathepsin B (Ki values of 0.39 and 32 nM, respectively), in competition with substrate. Cystatin E is thus a functional cysteine proteinase inhibitor despite relatively low amino acid sequence similarities with human cystatins (26-34% identity with sequences for the Family 2 cystatins C, D, S, SN, and SA; <30% with the Family 1 cystatins, A and B, and domains 2 and 3 of the Family 3 cystatin, kininogen). Unlike other human low Mr cystatins, cystatin E is a glycoprotein, carrying an N-linked carbohydrate chain at position 108. Northern blot analysis revealed that the cystatin E gene is expressed in most human tissues, with the highest mRNA amounts found in uterus and liver. A strikingly high incidence of cystatin E clones in cDNA libraries from fetal skin epithelium and amniotic membrane cells (>0.5% of clones sequenced) indicates a protective role of cystatin E during fetal development.

Cloning and characterization of a novel human DNase

The therapeutic significance of recombinant human DNase I in treating the patients with cystic fibrosis has risen our interests in identifying other human DNase I-like enzymes to study their biological significance. Here we described our work of cloning and characterization of a novel gene, which encodes a human protein homologous to human DNase I. A full length cDNA clone of this gene consists of 1290 bp, encoding a polypeptide of 306 amino acids. The deduced amino acid sequence of this novel human DNase (nhDNase) is 45% identical to that of human DNase I. Among sixteen human tissues examined by Northern Blot, high level expression of nhDNase was found in human liver and spleen. Recombinant protein of nhDNase was produced in a Baculovirus expression system and purified by chromatography and reverse-phase HPLC. Purified recombinant nhDNase migrated as a single band of about 33 kD molecular weight analyzed by SDS-PAGE. The DNase activity of nhDNase was demonstrated by assay of hydrolysis of S.S.DNA. Its activity was dependent upon the presence of divalent metal irons, calcium and magnesium. However, unlike bovine pancreas DNase I, nhDNase was not inhibited by G-actin of bovine muscle, which indicates the physiological significance of this enzyme in clinical implication.

Expression and reconstitution of NF-kappaB from insect cells using a baculovirus vector

NF-kappaB is a pleiotropic transcriptional activator originally identified by its ability to regulate immunoglogulin kappa light chain expression. Purification of this DNA-binding complex demonstrated that NF-kappaB is a heterodimer composed of two subunits, NFKB1 and RelA. Previous studies have shown that truncated versions of these proteins could be expressed and purified from bacterial cells. In the present study, we utilize a baculovirus expression vector system (BEVS) to overexpress each subunit independently to produce homodimers or together to reconstitute functional NF-kappaB. These proteins can be enriched to >70% homogeneity on a kappaB-agarose DNA- affinity column. The purified proteins are active in DNA binding as measured by electrophoretic mobility shift assays. Finally, transcriptional activation of these recombinant proteins can be measured by their ability to activate a kappaB-CAT reporter plasmid in transiently transfected/infected SF-9 cells. Thus, BEVS provides a method for production of full-length, transcriptionally active NF-kappaB proteins.

AP-4- and AP-5-like proteins from mouse L cells are trans-activators and bind to the GT-II region of SV40 early TRE in a mutually exclusive manner

Plasmids containing the cat reporter gene, transcription of which is directed by deletion mutants of the SV40 early region transcriptional regulatory element (SV40E TRE), were transfected into mouse L cells to determine the DNA motifs of SV40E TRE responsible for maximal gene expression. One deletion mutant, pSVE305, demonstrated a 50% reduction in CAT activity as compared to pSVE338, suggesting the importance of these 33 bp in directing efficient gene expression in mouse L cells. Introduction of triplet point mutations in this region and subsequent transfection studies in mouse L cells revealed three sites which were responsible for the reduction of CAT activity. These three mutations were located in the middle of the binding sites of three trans-activators: AP-3, AP-4 and AP-5. While the levels of CAT activity directed by SV40E TRE deletion mutants were similar in both HeLa and mouse L cells, the profiles of point mutants were different, suggesting that the activating ability of each nuclear factor is different from that of its counterpart in these two cell lines. Electrophoretic mobility shift assays (EMSA) demonstrated that binding of AP-4- and AP-5-like proteins of mouse L and HeLa cells to the GT-II motif occurs in a mutually exclusive manner. Furthermore, we observed a 'reverse competition' binding phenomenon which suggested a unique relationship between AP-4- and AP-5-like proteins of mouse L cells to the GT-II motif. Proteolytic mobility-shift analyses showed that an AP-5-like protein was more resistant to proteolytic digestion than an AP-4-like protein of mouse L cells.

Antisense inhibition of the p65 subunit of NF-kappa B blocks tumorigenicity and causes tumor regression

The NF-kappa B transcription factor, composed of two proteins, p50 and p65, is a pleiotropic activator that participates in the induction of a wide variety of cellular genes. Various cell adhesion molecules have NF-kappa B binding sites and may play an important role in inflammatory response, tumorigenicity, and metastasis. In an earlier study, we demonstrated that adhesion of diverse transformed cells was blocked by antisense inhibition of the p65 subunit of NF-kappa B. Since cell-substratum interactions play an important role in tumorigenicity, we reasoned that antisense p65 could inhibit tumorigenicity. In diverse transformed cell lines, phosphorothioate antisense oligonucleotides to p65 inhibited in vitro growth, reduced soft-agar colony formation, and eliminated the ability of cells to adhere to an extracellular matrix. Stable transfectants of a fibrosarcoma cell line expressing dexamethasone-inducible antisense RNA to p65 showed inhibition of in vitro growth and in vivo tumor development. In response to inducible expression of antisense RNA, a pronounced tumor regression was seen in nude mice. The administration of antisense but not sense p65 oligonucleotides caused a pronounced inhibition of tumorigenicity in nude mice injected with diverse tumor-derived cell lines. Inhibitors of NF-kappa B function may thus be useful in the treatment of cancer.

Acquisition of NFKB1-selective DNA binding by substitution of four amino acid residues from NFKB1 into RelA

The subunits of NF-kappa B, NFKB1 (formerly p50) and RelA (formerly p65), belong to a growing family of transcription factors that share extensive similarity to the c-rel proto-oncogene product. The homology extends over a highly conserved stretch of approximately 300 amino acids termed the Rel homology domain (RHD). This region has been shown to be involved in both multimerization (homo- and heterodimerization) and DNA binding. It is now generally accepted that homodimers of either subunit are capable of binding DNA that contains a kappa B site originally identified in the immunoglobulin enhancer. Recent studies have demonstrated that the individual subunits of the NF-kappa B transcription factor complex can be distinguished by their ability to bind distinct DNA sequence motifs. By using NFKB1 and RelA subunit fusion proteins, different regions within the RHD were found to confer DNA-binding and multimerization functions. A fusion protein that contains 34 N-terminal amino acids of NFKB1 and 264 amino acids of RelA displayed preferential binding to an NFKB1-selective DNA motif while dimerizing with the characteristics of RelA. Within the NFKB1 portion of this fusion protein, a single amino acid change of His to Arg altered the DNA-binding specificity to favor interaction with the RelA-selective DNA motif. Furthermore, substitution of four amino acids from NFKB1 into RelA was able to alter the DNA-binding specificity of the RelA protein to favor interaction with the NFKB1-selective site. Taken together, these findings demonstrate the presence of a distinct subdomain within the RHD involved in conferring the DNA-binding specificity of the Rel family of proteins.

Evidence for differential functions of the p50 and p65 subunits of NF-kappa B with a cell adhesion model

The p50 and p65 subunits of NF-kappa B represent two members of a gene family that shares considerable homology to the rel oncogene. Proteins encoded by these genes form homo- and heterodimers which recognize a common DNA sequence motif. Recent data have suggested that homodimers of individual subunits of NF-kappa B can selectively activate gene expression in vitro. To explore this possibility in a more physiological manner, murine embryonic stem (ES) cells were treated with phosphorothio antisense oligonucleotides to either p50 or p65. Within 5 h after exposure to phosphorothio antisense p65 oligonucleotides, cells exhibited dramatic alterations in adhesion properties. Similar findings were obtained in a stable cell line that expressed a dexamethasone-inducible antisense mRNA to p65. Although antisense oligonucleotides raised against both p50 and p65 elicited a significant reduction in their respective mRNAs, only the cells treated with antisense p50 maintained a normal morphology. However, 6 days following removal of leukemia-inhibiting factor, a growth factor which suppresses embryonic stem cell differentiation, adhesion properties of cells treated with the antisense p50 oligonucleotides were markedly affected. The ability of the individual antisense oligonucleotides to elicit differential effects on cell adhesion, a property dependent upon the stage of differentiation, suggests that the p50 and p65 subunits of NF-kappa B regulate gene expression either as homodimers or as heterodimers with other rel family members. Furthermore, the finding that reduction in p65 expression alone had profound effects on cell adhesion properties indicates that p65 plays an important role in nonstimulated cells and cannot exist solely complexed with the cytosolic inhibitory protein I kappa B.

I-Rel: a novel rel-related protein that inhibits NF-kappa B transcriptional activity

The NF-kappa B transcription factor complex is comprised of two subunits, p50 and p65, that share significant homology to the rel oncogene. We have isolated a cDNA encoding a novel 66-kD rel-related protein, designated I-Rel. Unlike other rel-related proteins, I-Rel does not interact with DNA. I-Rel forms heterodimers with p50, however, and greatly attenuates its DNA-binding activity--an effect probably resulting from the presence of a domain inhibitory to DNA binding present within the 121 amino-terminal residues of I-Rel. In contrast, I-Rel does not associate with p65. Transfection experiments demonstrate that I-Rel suppresses NF-kappa B-induced transcription, probably through its association with p50. Expression of I-Rel mRNA is induced by mitogenic stimulation and accumulates after the appearance of p50 transcripts. Our findings suggest that p50 and I-Rel are components of a feedback pathway where expression of I-Rel may modulate indirectly the expression of genes responsive to the NF-kappa B transcription factor complex.

The SV40 early transcriptional regulatory element is unable to direct gene expression in pituitary GH-3 cells

The SV40 early (SV40E) transcriptional regulatory element (TRE) is able to direct heterologous gene expression in a variety of eukaryotic cell lines. This ability is conferred, in part, by the presence of several cis-elements. Transfection studies, mutational analyses, and in vitro DNA binding assays have demonstrated that the SV40E TRE is capable of interacting with several cellular transcription (trans) factors. In the present study, we have investigated the inability of the SV40E TRE to direct gene expression in cultured rat anterior pituitary GH-3 cells. Gel shift analysis demonstrated that nuclear factors within these cells can recognize and specifically bind to DNA containing SV40 enhancer sequences. Surprisingly, we have found that both HeLa and GH-3 cells possess relatively equal quantities of Sp1-specific RNA; however, a dramatic decrease in Sp1 protein was seen in GH-3 cells. Transfection studies utilizing CAT reporter plasmids revealed that the intact SV40E TRE is inactive in these cells, and that subsequent deletion of a region(s) where nuclear factor binding occurs does not result in detectable levels of gene expression. Thus, removal of cis-sites potentially involved in repressor binding does not result in activation of the SV40E TRE in these cells. Subcloning an SV40 enhancer fragment upstream of a heterologous TK promoter yielded chimeric TREs that could direct high levels of gene expression in HeLa but not GH-3 cells. Therefore, the prototypic SV40 enhancer, in the context of GH-3 cells, cannot enhance gene expression.

Importance of SV40 early 5' distal sequences in directing heterologous gene expression

The chloramphenicol acetyltransferase-encoding reporter gene (cat) is used extensively in assessing the ability of transcriptional regulatory elements (TRE) to direct gene expression in eukaryotic cells. Two commonly utilized plasmids contain the cat coding sequences under the transcriptional control of the Rous sarcoma virus LTR (pRSVcat) or simian virus 40 early (SV40E) promoter (pSV2cat). In the present study, we have recloned the RSV-LTR and SV40E TRE into a pUC18 vector. Direct comparison of these TRE in different plasmid vectors, as well as reevaluation of their relative level of cat expression revealed: (1) a small but significant increases in SV40E-directed reporter gene expression was observed when the TRE was inserted into the pUC18 vector; and (2) a significant increase in SV40E-directed gene expression was realized by inclusion of the 69-bp 5' of the sequences present in pSV2cat. These distal sequences are required for maximal activity of the SV40 TRE in the cell lines tested.

Mutations in the third alpha-helix of bovine growth hormone dramatically affect its intracellular distribution in vitro and growth enhancement in transgenic mice

To investigate the relationship between the secondary structure of the third alpha-helix (amino acids 109-126) of bovine growth hormone (bGH) and the biological activity of the molecule, proline or glycine residues have been used as substitutes for native amino acids at positions 114, 118, 121, and 126, respectively. Mutations at the positions 114, 118, and 121 resulted in a dramatic decrease in bGH secretion by transiently transfected mouse L cells whereas the substitution of glycine for glutamate at position 126 (bGH-E126G) did not affect secretion. Immunofluorescence staining revealed that those nonsecretory bGH mutations possessed a different intracellular location as compared with wild-type bGH or the mutated secretory forms of bGH. Similar results were seen in the distribution of these mutated bGH molecules in transfected rat GH-3 cells. Transgenic mice that express wild-type bGH or bGH-E126G grew to approximately 1.6 times the mass of nontransgenic littermates. Transgenic mice that express two nonsecretory forms of mutated bGHs were found to lack the enhanced mouse growth phenotype in spite of elevated levels of serum bGH. These results suggest that the secondary structure in the third alpha-helix of bGH may be important for efficient intracellular targeting in vitro and in growth promotion in transgenic mice.

A comparison of transcriptional regulatory element activities in transformed and non-transformed rat anterior pituitary cells

Transformed (GH-3) and non-transformed (P3) rat anterior pituitary cells were compared in their ability to direct expression of plasmids containing a variety of eukaryotic transcriptional regulatory elements (TREs). These include the herpes simplex virus thymidine kinase (HSV-TK), Rous sarcoma virus long terminal repeat (RSV-LTR), simian virus 40 early (SV-40E), human cytomegalovirus immediate-early (CMV-IE) and mouse metallothionein 1 (mMT-1) TREs. Chloramphenicol acetyl transferase (CAT) gene expression served as a reporter in this study. Following transient transfection, the cell lines exhibited similar profiles of TRE utilization. In each cell line. CMV-IE was most efficient in directing reporter gene expression, although 2-fold greater activity was observed in GH-3 versus P3 cells. RSV-LTR directed gene expression was lower than that of CMV-IE while both HSV-TK and SV-40E were inactive in each cell line. Also, the mMT-1 promoter was inducible by addition of ZnCl2 to the culture media, though the level required for maximal activation differed between the two cell lines. Transfected GH-3 and P3 cells, therefore, displayed similar TRE utilization profiles yet significant differences were observed in the ability of these cell lines to respond to specific regulatory elements.

Expression of a cytomegalovirus-human growth hormone-releasing hormone precursor fusion gene in transfected GH3 cells

Pituitary GH3 cells were transfected with a human growth hormone-releasing hormone (hGRH) precursor minigene fused to the promoter region of either a cytomegalic immediate early gene (pCMV) or the mouse metallothionein-1 gene (mMT) to examine the molecular heterogeneity of the translation products. Expression of the hGRH message occurred following transfection of the cells with each fusion gene. Extracts of pCMV-hGRH-transfected GH3 cells as well as the culture medium contained detectable levels of immunoreactive (ir)-hGRH peptides. Analysis of molecular heterogeneity by reverse-phase high performance liquid chromatography and radioimmunoassay indicated that both mature forms of hGRH (hGRH(1-44)-NH2 and hGRH(1-40)-OH) were synthesized in the cells, although hGRH(1-44)-NH2 was the primary form secreted into the medium. A high molecular weight form of ir-hGRH, believed to represent the hGRH precursor (or a partially processed form of the precursor) was detected in cells and, in smaller amounts, in the medium. Several ir-hGRH peptides, presumed cleavage products of the mature forms of hGRH, were also found. The efficiency of processing of the hGRH precursor and metabolism of the mature hormonal forms in transfected cells grown in the presence of four different peptidase inhibitors varied with the inhibitor present. Transfected GH3 cells, therefore, possess all of the necessary enzymes for and are capable of processing the hGRH precursor to mature GRH and provide a model to study hGRH biosynthesis.

In vitro expression and characterization of the translation start site of the psbA gene product (QB protein) from higher plants

The psbA gene from higher plants, which codes for the atrazine herbicide binding protein of photosystem II (QB protein), has been recently sequenced by various laboratories. From these data there are two potential translation sites, one yielding a protein of 38,500 kd and another a protein of 34,500 kd. In the present study, cloned psbA gene sequences from maize, tobacco, and pea have been expressed in a highly defined E. coli in vitro transcription/translation system. In order to determine the start site of translation, we also have employed a simplified E. coli system designed to synthesize the first di- or tripeptide of the gene product. From these results, it is clear that the first ATG of the longest open reading frame of the psbA gene, that begins fMet-Thr, is not recognized in vitro. Instead, the next downstream Met at position 37 is the initiation site, since the expected dipeptide fMet-Ile is synthesized from all psbA clones. These data are in accord with the in vivo results that the gene product is a precursor protein of 34,500 kd.

Improved methods for production, isolation, and assay of two new chlorisoxazoline amino acid antitumor antimetabolites: U-42, 126 and U43, 795

Improved fermentation and isolation procedures for antitumor antimetabolites U-42,126 and U-43,795 increased drug yields 30-fold. The sensitivity limit of a newly developed assay is 0.03 mug of U-42,126 and 2.0 mug of U-43,795 per ml. The in vitro antimicrobial effect of both drugs was antagonized by histidine.