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Biomedical subjects

J Otis

Publications and source records attributed to J Otis.

At least 19 recordsLinked to original sources
PubMed2001

Risk factors associated with HIV infection among young gay and bisexual men in Canada.

OBJECTIVE: To assess risk factors associated with HIV prevalence and incidence among gay and bisexual men in two prospective Canadian cohorts. METHODS: The Vanguard Project and the Omega Cohort are prospective cohort studies of gay and bisexual men ongoing in Vancouver and Montreal, respectively. For this analysis, baseline sociodemographic characteristics, sexual behavior, and substance use data from these two cohorts were combined. Assessment of risk factors for HIV seroprevalence and seroconversion were carried out using univariate and multivariate analysis. RESULTS: This analysis was based on 1373 gay and bisexual men aged 16 to 30 years. Men who were HIV-seropositive at baseline (n = 48) were more likely to report living in unstable housing, to have had less than a high school education, and to have been unemployed than those who were HIV-negative (n = 1325). HIV-positive men were also more likely to report having engaged in sexual risk behavior, including having had consensual sex at a younger age, having had at least 6 partners during the previous year, ever having been involved in the sex trade, and having engaged in unprotected receptive anal intercourse. With respect to substance use, HIV-positive men were more likely to report the use of crack, cocaine, heroin, and marijuana and to use injection drugs. Similarly, men who seroconverted during the course of the studies (n = 26) were more likely to report having less than a high school education and having lived in unstable housing at baseline. Compared with HIV-negative men, men who seroconverted were more likely to report ever having been involved in the sex trade and engaging in unprotected receptive anal intercourse. Reports of cocaine use and injection drug use were also significantly higher for men who seroconverted compared with HIV-negative men. CONCLUSIONS: Our data indicate that HIV-positive gay and bisexual men are more likely to be living in unstable conditions and to report more risky sexual and substance use behaviors than HIV-negative men.

Adolescent↗
PubMed2000

Correlates of risky behaviors among young and older men having sexual relations with men in Montréal, Québec, Canada. Omega Study Group.

OBJECTIVE: To assess characteristics associated with 1) age and 2) recent unprotected anal sex with casual partners among men having sexual relations with men (MSM) participating in the Omega Cohort, Montréal, Québec, Canada. METHODS: The Omega Cohort is a study of the incidence and psychosocial determinants of HIV infection among MSM living in Montréal. MSM complete a questionnaire and are tested for HIV every 6 months. RESULTS: Thirteen percent of young MSM (< 30 years of age, n = 355) and 12% of older MSM (> or = 30 years of age, n = 455) reported recent unprotected anal sex with casual partners. The predictors of this latter behavior were: not living with a male sexual partner, unprotected anal sex with regular partner, > 5 casual partners, alcohol/drug use before anal sex, and having difficulties with procedures needed for safe sex. Among young MSM, additional predictors were: to have been living in Montreal for less than 1 year and to have exchanged money for sex. Among older MSM, additional predictors were: female sexual partners, unprotected anal sex with an HIV-infected partner, and feeling invulnerable to AIDS. CONCLUSION: Young Omega participants do not have more risky behaviors than older participants. Some predictors of recent risk behaviors with casual partners were different between the two groups. Prevention programs should be adapted consequently.

Adolescent↗
PubMed2000

In vitro airway responsiveness of Flinders sensitive and resistant line rats.

Recently, we reported that freely moving Flinders sensitive line rats (FSL, selectively bred for their cholinergic hyperresponsiveness) are more susceptible to allergen-induced airway hyperresponsiveness than their control counterparts-Flinders resistant line (FRL) rats. In this study the two Flinders lines were compared for responsiveness of excised tracheal and primary bronchial smooth muscle in vitro. FSL tissues were slightly but significantly more sensitive to cholinergic stimulation than FRL tissues (slightly lower EC(50) value for carbachol) but the FRL tissues were more responsive, exhibiting larger amplitude of response. Surprisingly, previous exposure to allergen challenge was accompanied by reduced in vitro responses to spasmogens in both rat lines. We conclude that FSL and FRL airways do not differ greatly with respect to sensitivity to cholinergic stimulation in vitro and that inflamed airways show reduced in vitro responses to spasmogens. The discrepancy between the in vivo and in vitro findings suggests that responsiveness of airway smooth muscle involves regulation from both proximal and distal sites.

Airway Resistance↗
PubMed2000

Symptom perception during acute bronchoconstriction.

The hypothesis underlying the present study was that some of the variability in symptom intensity seen during acute bronchoconstriction may result from varying intensities of several stimuli yielding several sensations that can be identified by specific descriptive expressions (symptoms). A total of 232 subjects inhaled methacholine in doubling concentrations to a 20% decrease in FEV(1), or 64 mg/ml. The study identified the prevalence of dyspnea, nonspecific discomfort associated with the act of breathing, and 10 specific symptom expressions. Each symptom intensity was rated in Borg scale units. The contribution of the specific symptoms to the intensity of dyspnea is illustrated in the following equation (r = 0. 84): Dyspnea = 0.44 + 0.19 Difficult breathing + 0.41 Chest tightness + 0.20 Breathlessness + 0.14 Labored breathing + 0.11 Chest pain. Dyspnea was more intense with broncho-constriction, baseline pulmonary impairment, weight, and sex (being female). Dyspnea was less intense with age (being older) and as airway responsiveness to methacholine increased (p < 0.05 for all factors). Chest tightness and chest pain were at polar extremes on the discrimination scale, i.e., easily discriminated; chest tightness, difficult and labored breathing were not easily discriminated.

Adult↗
PubMed2000

Association of hepatitis B virus infection with other sexually transmitted infections in homosexual men. Omega Study Group.

OBJECTIVES: This study determined the prevalence and factors associated with hepatitis B virus (HBV) infection among men who have sex with men. METHODS: At the baseline visit of an HIV study among men who have sex with men, we asked about HBV vaccination status and tested for HBV markers. RESULTS: Of 625 subjects, 48% had received at least 1 dose of HBV vaccine. Of 328 unvaccinated men, 41% had 1 or more HBV markers. HBV prevalence increased markedly with age and was associated with many sexual and drug-related behaviors. In a multivariate model, 7 variables were independently associated with HBV infection: ulcerative sexually transmitted diseases (odds ratio [OR] = 10.1; 95% confidence interval [CI] = 2.6, 54); injection drug use (OR = 5.2; 95% CI = 1.2, 26); gonorrhea or chlamydia (OR = 4.0; 95% CI = 1.9, 8.9); sexual partner with HIV/AIDS (OR = 3.6; 95% CI = 1.8, 7.1); 50 or more casual partners (OR = 3.4; 95% CI = 1.6, 7.1); received money for sex (OR = 3.0; 95% CI = 1.2, 7.8); and 20 or more regular partners (OR = 2.5; 95% CI = 1.1, 6.1). CONCLUSIONS: In Montreal, men who have sex with men are at risk for HBV infection, but a substantial proportion remain unvaccinated; new strategies are required to improve coverage. Men who have sex with men and who have a sexually transmitted infection, especially a genito-ulcerative infection, appear to be at particularly high risk for HBV infection.

Adult↗
PubMed1999

Factors associated with hepatitis B vaccination among men having sexual relations with men in Montreal, Quebec, Canada. Omega Study Group.

OBJECTIVE: To determine factors associated with hepatitis B virus (HBV) vaccination status among HIV-uninfected men who have affective and sexual relations with men (MASM) in Montreal, Quebec, Canada. METHODS: The Omega Cohort is a study of the incidence and psychosocial determinants of HIV infection among MASM in Montreal. Participants complete a questionnaire and are HIV-tested every 6 months. At baseline, we also performed testing for HBV markers and collected data on HBV vaccination history. RESULTS: Forty-six percent of 653 participants had received at least one dose of HBV vaccination, whereas 28% were completely vaccinated. Lack of vaccination was associated with injection drug use, having > or =20 regular lifetime partners, living outside Montreal, not having sex in bathhouses, and not having consulted a physician aware of the participant's sexual orientation. Among vaccinated MASM, incomplete vaccination was associated with having <20 lifetime casual partners, trading sex for drugs, having given goods for sex, having had unprotected anal sex with regular partners, and having no history of a previous sexually transmitted disease. CONCLUSION: A significant proportion of Montreal's MASM, some of whom are at risk of contracting HBV through sexual and parenteral transmission, have not been vaccinated for HBV. Men who have affective and sexual relations with men should be educated about the risk of HBV transmission and the seriousness of the disease.

Adolescent↗
PubMed1998

[Contraceptive behavior of young Latin-American adults living in Montreal].

Recent research on the contraceptive practices of Hispanics adolescents living in Latin America and the United-States indicates that their practices are inadequate. However, contraceptive practices can vary according to levels of traditionalism and acculturation. In order to verify these hypotheses, the contraceptive behaviors of a group of 114 young adults from both genders of Hispanic origin were evaluated. Results indicate that half of the participants did not use any contraceptive method during the first intercourse and that condoms were the most common method. Contrary to American results, acculturation levels were not significant in contraceptive use. Degree of traditionalism in sexual roles was more significant.

Adult↗
PubMed1997

Regular exercise in 30- to 60-year-old men: combining the stages-of-change model and the theory of planned behavior to identify determinants for targeting heart health interventions.

The theory of planned behavior and the stages-of-change model were used to gain a clearer understanding of the factors associated with regular exercise in order to plan more effective programs in heart disease prevention. The study was conducted using a self-administered postal questionnaire sent to a sample of 2,269 men 30 to 60 years of age. Nearly a quarter (23.3%) of respondents were physically inactive, of whom 10.5% were in the precontemplation and 12.8% in the contemplation stages; 42.1% exercised less than twice a week, of whom 22.4% were in the preparation I and 19.7% in the preparation II stages. Only 34.6% were in the action stage, exercising regularly for at least 20 minutes twice a week or more with the intention of continuing to do so. Logistic regression indicated that the variables derived from the theory of planned behavior, namely attitude, subjective norm and perceived behavioral control, were differently associated with the stages of behavior. Perceived behavioral control was strongly significant in all stages. Attitude was related with stages in which individuals have intention of exercising (contemplation and preparation II). In contrast, subjective norm seemed to be associated with stages in which individuals have no intention of doing so (precontemplation and preparation I). By identifying the specific needs of sub-groups, the results can help define programs most likely to accelerate men to the stage of regular exercise, part of an effective strategy for heart health promotion in this high-risk population.

Adult↗
PubMed1996

Diet and exercise profiles of 30- to 60-year-old male smokers: implications for community heart health programs.

The aim of this study was to estimate the prevalence of diet and exercise behaviors in middle-aged male smokers and identify their determinants of behaviors, with the ultimate goal of designing more effective interventions in a community heart health program. Self-administered, postal questionnaires produced a sample of n = 671 male smokers, 30 to 60 years of age residing in Laval, Quebec's second most populous city. Variables for the study were derived from the theory of planned behavior. Correspondence analysis explained 65% of the variance, classifying smokers into five groups based on diet and exercise behavior. Group 1, smokers with diet and exercise behaviors deemed inadequate for heart health, comprised 43% of the total. Groups 2 and 3, smokers with a diet deemed inadequate or needing improvement respectively, and Group 4, smokers with inadequate exercise, comprised 42% of the total. Group 5, smokers with neither of the other high-risk behaviors, comprised 15% of the total. Four significant variables contrasted Groups 1 to 4 with group 5: age, number of cigarettes smoked daily, and perceived behavioral control (PBC) in both diet and exercise. However, coefficients for age and smoking were weak for all groups. Coefficients for PBC in diet were high and negative only for smokers with an inadequate one. For PBC in exercise, they were high and negative only for smokers who exercised inadequately. Intervention groups based on specific deficiencies in diet and exercise behaviors were then identified. Therefore, the results suggest that smoking cessation programs may be made more effective by targeting specific sub-groups and by providing resources and opportunities to counteract the lack of perceived behavioral control in middle-aged male smokers vis-a-vis diet and exercise.

Adult↗
PubMed1991

Prolonged protection against methacholine-induced bronchoconstriction by the inhaled beta 2-agonist formoterol.

Formoterol fumarate is a new, high-affinity, beta 2-adrenergic receptor agonist that causes bronchodilation for at least 12 h. The purpose of this study was to compare the magnitude and duration of the effect of inhalation of formoterol (12 and 24 micrograms), albuterol (200 micrograms), and placebo in terms of protection against methacholine-induced bronchoconstriction. The 16 stable adult asthmatic subjects were studied on four separate study days. On each study day the subjects inhaled 2 puffs of the study medication, and methacholine tests were performed at 30 min and 4, 8, and 12 h later. Results were expressed as the provocative concentration of methacholine required to cause a 20% fall in FEV1 (PC20). At 30 min, 12 and 24 micrograms formoterol caused a mean 14- to 20-fold decrease in responsiveness, and albuterol a 12-fold decrease. However, albuterol had no significant protective effect at 4 h or thereafter, whereas there was still an 8-fold decrease in responsiveness for 24 micrograms formoterol and a 6-fold decrease for 12 micrograms formoterol at 12 h. This study has shown that both doses of formoterol were still actively protective against induced bronchoconstriction 12 h after inhalation, with minimal side effects. This suggests that formoterol may prove to be a very useful bronchodilator for the treatment of patients with asthma who have significant airway hyperresponsiveness or nocturnal symptoms and who require inhaled beta 2-agonists at least twice daily.

Administration, Inhalation↗
PubMed1990

The inhibitory influence of tracheal mucosa mounted in close proximity to canine trachealis.

Reduced smooth muscle contractile responses to agonists occur in the presence of epithelium, perhaps due to the release of an epithelium-derived relaxing factor (EpDRF). It is not clear whether the release of EpDRF requires the direct attachment of the epithelium to the smooth muscle. In the present study, using isolated canine tracheal smooth muscle strips, we examined whether the inhibitory effects of airway mucosa require the attachment of the mucosa to smooth muscle. The smooth muscle contractile responses to acetylcholine and histamine were reduced in the presence of airway mucosa, whether the mucosa was attached or in close proximity. The inhibitory effect mediated by the airway mucosa therefore is not dependent on mucosal attachment to smooth muscle. This phenomenon appears to be due to the release of a soluble, short-acting mediator from the airway mucosa.

Acetylcholine↗
PubMed1990

Stereo and motion cues in preattentive vision processing--some experiments with random-dot stereographic image sequences.

Low-level preattentive vision processing is of special interest since it seems the logical starting point of all vision processing. Exploration of the human visual processing system at this level is, however, extremely difficult, but can be facilitated by the use of stroboscopic presentation of sequences of random-dot stereograms, which contain only local spatial and temporal information and therefore limit the processing of these images to the low level. Four experiments are described in which such sequences were used to explore the relationships between various cues (optical flow, stereo disparity, and accretion and deletion of image points) at the low level. To study these relationships in more depth, especially the resolution of conflicting information among the cues, some of the image sequences presented information not usually encountered in 'natural' scenes. The results indicate that the processing of these cues is undertaken as a set of cooperative processes.

Attention↗
PubMed1986

Serum enzyme, myoglobin and muscle strength relationships in polymyositis and dermatomyositis.

Strength of the quadriceps and hamstring groups was biomechanically assessed in terms of isometric torque production in 14 patients with inflammatory myopathy. Eleven had polymyositis and 3, dermatomyositis. Determinations of serum creatine kinase, lactate dehydrogenase, transaminase, and myoglobin were simultaneously obtained over an average period of observation of 1.8 years. In certain individual patients, there were significant correlations between laboratory indices and strength during the entire course of illness. In others, this was not the case. In the total group of patients, absolute values of the laboratory indices did not correlate well with strength except in the case of serum myoglobin, where there a significant inverse relationship. Logarithmic transformations of the laboratory data increased the inverse correlations. High strength and low myoglobin were related to high prednisone dose. Since laboratory guides are not always related to disease activity, quantitative assessment of muscle strength is necessary.

Adult↗
PubMed1980

The dog heartworm (Dirofilaria immitis) in man. An epidemic pending or in progress?

Human infection with the dog heartworm (Dirofilaria immitis) may lead to focal pulmonary infarction with granuloma formation. The resulting roentgenographic coin lesion may require a diagnostic thoracotomy in consideration of malignancy. Because of sometimes enigmatic histopathological characteristics, this process may not be receiving the recognition it deserves. Furthermore, the dramatic increase of primary (canine) host infections in the United States presages an increase of secondary (human) host infections. Many thoracotomies will be performed for this innocuous process unless the dirofilarial agent can be controlled or the human pulmonary lesion can be reliably identified without operation.

Aged↗