Does age matter? Sexual event-level analysis of age-disparate sexual partners among gay, bisexual and other men who have sex with men (GBM) in Vancouver, Canada

BACKGROUND

To determine factors associated with age-disparate sexual partners among Vancouver gay, bisexual and other men who have sex with men (GBM).

METHODS

Sexually active GBM aged ≥16 years were recruited from February 2012 to February 2014. Participants self-completed a questionnaire on demographics, attitudes and sexual behaviour and substance use at last sexual event with five most recent partners. Two generalised linear mixed models identified factors associated with: (1) 'same-age' (referent), 'younger' or 'much-younger' and (2) 'same-age' (referent), 'older' or 'much-older' partners. Statistical interactions between age and HIV status were tested.

RESULTS

Participants (n=719) were predominantly gay (85.1%), White (75.0%), HIV-negative/unknown status (72.9%) with median age of 33 years (Q1,Q3: 26,47). A minority of sexual events were reported with much-older/much-younger partners (13.7%). In the multivariable models, GBM reporting older partners were more likely to be Asian or Latino, have greater Escape Motivation scores, report their partner used erectile dysfunction drugs (EDDs) and have received something for sex; compared with condom-protected insertive anal sex, participants with older partners were more likely to report condomless insertive anal sex with a serodiscordant or unknown status partner or no insertive anal sex. GBM reporting older partners were less likely to be bisexual-identified, have given something for sex and report event-level alcohol and EDD use. GBM reporting younger partners were more likely to have annual incomes >$30 000 and have met their partner online. As per significant statistical interactions, age-disparate relations were more common for younger HIV-positive and older HIV-negative GBM.

CONCLUSIONS

Differences among age-disparate partners highlight important targets for health promotion and future research.

Awareness and use of nonoccupational post-exposure prophylaxis among men who have sex with men in Vancouver, Canada

OBJECTIVES

Nonoccupational post-exposure prophylaxis (nPEP) is a strategy to reduce the risk of HIV infection in those with high-risk exposure. This study characterized nPEP awareness among gay, bisexual and other men who have sex with men (MSM) in Metro Vancouver, British Columbia, Canada after a pilot nPEP programme established in 2012.

METHODS

Momentum Health Study participants were MSM aged ≥16 years recruited via respondent-driven sampling (RDS) who completed a computer-assisted self-interview. Stratifying patients by HIV status, we used multivariable logistic regression with backward selection to identify factors associated with nPEP awareness. All analyses were RDS-adjusted.

RESULTS

A total of 51.9% (112 of 173) of HIV-positive and 48.5% (272 of 500) of HIV-negative participants had heard of nPEP. Only 3% (five of 106) of HIV-negative participants who reported recent high-risk sex used nPEP. Generally, nPEP awareness was higher for participants who engaged in sexual activities with increased HIV transmission potential. Factors associated with greater awareness among HIV-negative participants included recent alcohol use, higher communal sexual altruism, previous sexually transmitted infection diagnosis, and greater perceived condom use self-efficacy. Other factors associated with greater awareness among HIV-negative participants included white race/ethnicity, gay sexual identity, more formal education, lower personal sexual altruism, and Vancouver residence. Greater nPEP awareness among HIV-positive participants was associated with greater perceived agency to ask sexual partners' HIV status and more frequently reporting doing so, a higher number of lifetime receptive sex partners, and greater access to condoms.

CONCLUSIONS

Following implementation of an nPEP pilot programme, nPEP awareness among HIV-negative MSM was 51% and use was 3%. These data support the need to expand access to and actively promote nPEP services.

Branched isomeric 1,2,3-triazolium-based ionic liquids: new insight into structure–property relationships

Series of branched isomeric 1,2,3-triazolium-based ionic liquids (ILs) were synthesized and characterized. The effect of branching on thermal and physical properties is investigated.

Inkjet printing for high-throughput cell patterning

The adaptation of inkjet printing technology to the complex fields of tissue engineering and biomaterial development presents the potential to increase progress in these emerging technologies through the implementation of this high-throughput capability via automated processes to enable precise control and repeatability. In this paper, a method of applying high-throughput inkjet printing to control cellular attachment and proliferation by precise, automated deposition of collagen is presented. The results indicate that commercial inkjet printing technology can be used to create viable cellular patterns with a resolution of 350 microm through the deposition of biologically active proteins. This method demonstrates a combination of off-the-shelf inkjet printing and biomaterials and has potential to be adapted to tissue engineering and colony patterning applications. Adapting this method into the three-dimensional construction of cellular structures for eventual high-throughput tissue engineering using a bottom-up approach is possible.

Severe local hypothermia from laparoscopic gas evaporative jet cooling: a mechanism to explain clinical observations

BACKGROUND AND OBJECTIVES

Explanations for laparoscopic-induced hypothermia fail to explain clinical observations. It is possible that water evaporation occurs from the jet stream of gas inflation resulting in tissue surface super-cooling leading to tissue damage and drying.

METHODS

Theoretical calculations based on thermal conductivity, mass transfer effects and heat flux considerations correlated closely with synthetic and tissue experiments. Thermocouple measurements at a rate of 15 data points per second were performed.

RESULTS

Cooling rates of 10 to 25 degrees centigrade per second for high flow rates were found based on gas flow rate and effective size of gas delivery site. These rapid temperature drops extended beyond a 2 cm2 diameter.

CONCLUSIONS

Evaporative cooling accounts for significant hypothermia. The cooling is dependent on the lack of water vapor in the gases currently used during laparoscopy. Cooling rates are independent of height from tissue and geometry of delivery port. Heating and hydrating the gas to a physiologic condition eliminates hypothermia and tissue dessication.

Histone-specific Th0 and Th1 clones derived from systemic lupus erythematosus patients induce double-stranded DNA antibody production

OBJECTIVE

To investigate whether histone-specific T helper (Th) cells that are able to induce anti-double-stranded DNA (anti-dsDNA) antibodies can be isolated from patients with systemic lupus erythematosus (SLE) and to characterize the cytokine secretion pattern of such Th clones.

METHODS

Peripheral blood mononuclear cells from SLE patients and healthy donors were stimulated with autologous apoptotic cell material or purified histones, expanded with interleukin-2 (IL-2), and cloned by limiting dilution. Histone reactivity of clones was examined by histone-specific proliferation and cytokine release. Cytokines were determined by enzyme-linked immunosorbent assay (ELISA) and CTLL-2 bioassay. Induction of anti-dsDNA antibodies was measured in cocultures of autologous B cells and Th clones by ELISA:

RESULTS

Numerous histone-specific T cell receptor (TCR) alpha/beta+ Th clones were established from 2 of 3 patients with active SLE and from 1 of 2 healthy individuals. Most Th clones secreted IL-2, interferon-gamma (IFNgamma), and IL-4, whereas some produced predominantly IL-2 and IFNgamma. Th clones that could stimulate the production of anti-dsDNA antibodies were derived from SLE patients and from a healthy individual.

CONCLUSION

Th cells specific for histones may play an important role in the pathogenesis of SLE by inducing autoantibodies to dsDNA. Both Th1 and Th2 cytokines may be involved in the pathogenesis of SLE. The presence of histone-specific Th cells in a healthy individual indicates the importance of peripheral tolerance for preventing autoimmunity to nuclear antigens.

Sedentism and child health among Rendille pastoralists of northern Kenya

Many nomadic pastoralists of Africa are settling near towns and famine-relief centers in response to drought-induced livestock loss, loss of pasture land, increased involvement in market economies and political turmoil including civil war. The present study uses measurements of child health, particularly morbidity, dietary and growth patterns, to evaluate the consequences of sedentism for three Rendille communities of northern Kenya. A nutritional and health survey utilizing interviews, anthropometric measurements, physical examinations and hemoglobin measurements was conducted for 105 mothers and their 174 children under six years of age in three Rendille communities, one fully nomadic and two sedentary, in July 1990, a year of above average rainfall, and again in June 1992, a drought year. Results indicate that while the nomadic Rendille community of Lewogoso shares similar morbidity patterns with its sedentary counterparts and had similar numbers of malnourished children during the wet year, the sedentary communities had significantly more malnutrition among children under six during the dry year. Moreover, the children in the settled town of Korr had significantly higher levels of anemia. Differences in malnutrition are attributed to distinctive dietary regimes: during the drought, nomadic children consumed three times as much milk as the sedentary children, while settled children's diets concentrated on starches, fat and sugar. This study suggests that the pastoral nomadic diet, particularly one dependent on camels' milk, offers children better resistance to the pressures of drought and supports findings that the subsistence base of mixed-species pastoralism is superior to sedentary alternatives with respect to child health.

Demography of the Juang tribal population of Orissa

Demographic analysis of genealogical data collected in 1954 for 23 Juang villages was undertaken employing indirect estimation techniques and computer projection methodology. Results indicated that this group did not feature the historically high fertility levels associated with Indian tribal groups, although fertility was higher than previously reported for the Juang. The population did feature a mortality differential, with worse mortality conditions than the Indian national population at this time. Reversed sexual mortality differentials, common in South Asian populations, were also present for the Juang. Computer projection investigation revealed a steadily growing population, in contrast to some Indian tribal groups faced with extinction.

Children's understanding of psychiatric hospitalization

The authors summarize the results of what they believe to be the first systematic study of children's concepts of their own psychiatric hospitalization. They found that children 6-12 years old are able to gain progressive insight into their problems and the roles that therapeutic staff (doctors and nurses) play in treatment. These findings provide new information about the child's point of view and cognitive understanding of psychiatric hospitalization, illness, and treatment. The findings suggest that preadmission legal hearings addressing the child's understanding of the nature of psychiatric hospitalization would not be meaningful.

Drug-plasma protein binding in Kutchin Athapaskan indians

Free fractions of diazepam (D alpha), warfarin (W alpha), and methadone (M alpha) were measured in plasma obtained from 37 Kutchin Athapaskan Indians. Mean D alpha (3.42%) varied directly with free fatty acid concentration (r = 0.65, P less than 0.001) and was higher than previously found in other groups. These higher levels of fatty acids were associated with lower W alpha (r = -0.43, P = 0.007), and W alpha rose with time after a meal (r = 0.42, P = 0.01) when fatty acids usually fall. Mean W alpha was 0.72% and increased with age (r = 0.47, P = 0.004). In multivariate analysis, age, fatty acids, and time after the last meal together accounted for 42% of intersubject variation in W alpha. W alpha and D alpha were inversely correlated (r = -0.33, P = 0.04), a result of the strong effects of fatty acids in these drugs. In contrast to both D alpha and W alpha, intersubject differences in M alpha correlated inversely with alpha 1-acid glycoprotein concentration (r = -0.50, P = 0.001), but not fatty acids.

Demography and computer simulation in historic village population reconstruction

"Demographic anthropology has given rise to methodological advances in the analysis of single community populations. However, the obstacles of small data bases and incomplete vital-event registration remain. This paper details one approach to these problems; the principles of community demography are incorporated with computer simulation methodology, with the goals of validating the internal consistency of and determining demographic secular trends from data commonly utilized in anthropological investigations." The approach is tested on data for the 250 inhabitants of Old Crow Village, Yukon Territory, Canada, in 1978.