Modeling of Microneedle Arrays in Transdermal Drug Delivery Applications

The use of computational tools for the development of technologies in fields such as medicine and engineering has facilitated the process of designing new components and devices for these areas. In this work, two proposals focused on a hollow microneedle array (MNA) for the administration of an analgesic drug are shown and evaluated by means of a computational fluid dynamics (CFD) simulation distributed in three stages. In the first stage, the behavior of lidocaine through the MNA was evaluated as a workflow. Then, the possible entry of the drug into the organism, which was established as a porous aqueous medium, was modeled. Finally, a joint simulation was performed to understand the general behavior in the interaction between the outflow of an MNA and the body to which lidocaine is administered. The input parameters to the simulation were set at a velocity of 0.05 m∙s^-1, at a pressure of 2000 Pa, the dominant behavior was defined as laminar flow, and a resistive pressure at the inlet of 400 Pa. Our results indicate that the vertical flow exhibits a better fluid distribution across the MNAs and favorable infiltration behavior, representing better delivery of the analgesic to the skin capillaries.

Phonon Dominated Thermal Transport in Metallic Niobium Diselenide from First Principles Calculations

Niobium diselenide (NbSe₂) is a layered transition metal dichalcogenide material which possesses unique electrical and superconducting properties for future nanodevices. While the superconducting, electrical, and bulk thermal transport properties of NbSe₂ have been widely studied, the in-plane thermal transport property of NbSe₂, which is important for potential thermoelectric applications, has not been thoroughly investigated. In this report, we study the lattice in-plane thermal transport of 2D NbSe₂ by solving the phonon Boltzmann transport equation with the help of the first principles calculation. The thermal conductivity obtained at room temperature is 12.3 W/mK. A detailed analysis shows that the transverse acoustic phonon dominates the lattice thermal transport, and an anomalously small portion of electron contribution to the total thermal conductivity is observed for this metallic phase. The results agree well with experimental measurements and provide detailed mode-by-mode thermal conductivity contribution from different phonon modes. This study can provide useful information for integrating NbSe₂ in nanodevices where both electrical and thermal properties are critical, showing great potential for integrating monolayer NbSe₂ to thermoelectric devices.

Analysis of the Part Distortions for Inconel 718 SLM: A Case Study on the NIST Test Artifact

The present paper evaluates the misalignment and geometry distortion of the standard National Institute of Standards and Technology (NIST) test artifact in Inconel 718 alloy, when several layers with and without supports are employed to manufacture it by the Selective Laser Melting (SLM) process. To this end, a coordinate-measuring machine (CMM) is used to measure the geometrical distortion in each manufacturing configuration, following the same measurement protocol. The results show that the laser path strategy favors a thermal gradient which, consequently, induces geometrical distortions in the part. To prove this hypothesis, a numerical simulation is performed to determine the thermal gradient and the pattern of the residual stresses. It was found that the geometrical distortion certainly depends on the position of the feature position and laser strategy, where thermal cycles and residual thermal stresses had an impact in the end-part geometry, especially if a high strength-to-weight ratio commonly used in aeronautics is present.

An evaluation of assumptions underlying respondent-driven sampling and the social contexts of sexual and gender minority youth participating in HIV clinical trials in the United States

Introduction:

Respondent-driven sampling has been an effective sampling strategy for HIV research in many settings, but has had limited success among some youth in the United States. We evaluated a modified RDS approach for sampling Black and Latinx sexual and gender minority youth (BLSGMY) and evaluates how lived experiences and social contexts of BLSGMY youth may impact traditional RDS assumptions.

Methods:

RDS was implemented in three cities to engage BLSGMY in HIV prevention or care intervention trials. RDS was modified to include targeted seed recruitment from venues, internet, and health clinics, and provided options for electronic or paper coupons. Qualitative interviews were conducted among a sub-sample of RDS participants to explore their experiences with RDS. Interviews were coded using RDS assumptions as an analytic framework.

Results:

Between August 2017 and October 2019, 405 participants were enrolled, 1,670 coupons were distributed, with 133 returned, yielding a 0.079 return rate. The maximum recruitment depth was 4 waves among seeds that propagated. Self-reported median network size was 5 (IQR 2–10) and reduced to 3 (IQR 1–5) when asked how many peers were seen in the past 30 days. Qualitative interviews (n=27) revealed that small social networks, peer trust, and targeted referral of peers with certain characteristics challenged network, random recruitment, and reciprocity assumptions of RDS. HIV stigma and research hesitancy were barriers to participation and peer referral.

Conclusions:

Small social networks and varying relationships with peers among BLSGMY challenge assumptions that underlie traditional RDS. Modified RDS approaches, including those that incorporate social media, may support recruitment for community-based research but may challenge assumptions of reciprocal relationships. Research hesitancy and situational barriers must be addressed in recruitment and study designs.

Numerical Simulation and Experimental Validation of Sheet Laser Forming Processes Using General Scanning Paths

This work presents numerical simulations and an experimental validation of sheet laser forming processes using general scanning paths with different laser beam operating parameters (i.e., power, diameter, and scanning speed) in two specific graphite coated stainless steel blanks (i.e., with thicknesses of 0.3 mm and 0.6 mm for the AISI 302 and 304 alloys, respectively). To this end, three specific laser forming tests involving single S-shaped, multiple circular, and single piecewise linear scanning paths are carried out. On the other hand, the numerical simulation of these tests is performed via a coupled thermomechanical finite element formulation, accounting for large viscoplastic strains, temperature-dependent material properties, and convection-radiation phenomena. The final bending angles provided by this model are found to be in good agreement with the experimental measurements for all of the cases studied. Therefore, this modeling framework can be established as a reliable approach to predict the material thermomechanical response during sheet laser forming using general scanning paths.

Age-Related Differences in Socio-demographic and Behavioral Determinants of HIV Testing and Counseling in HPTN 043/NIMH Project Accept

Youth represent a large proportion of new HIV infections worldwide, yet their utilization of HIV testing and counseling (HTC) remains low. Using the post-intervention, cross-sectional, population-based household survey done in 2011 as part of HPTN 043/NIMH Project Accept, a cluster-randomized trial of community mobilization and mobile HTC in South Africa (Soweto and KwaZulu Natal), Zimbabwe, Tanzania and Thailand, we evaluated age-related differences among socio-demographic and behavioral determinants of HTC in study participants by study arm, site, and gender. A multivariate logistic regression model was developed using complete individual data from 13,755 participants with recent HIV testing (prior 12 months) as the outcome. Youth (18-24 years) was not predictive of recent HTC, except for high-risk youth with multiple concurrent partners, who were less likely (aOR 0.75; 95% CI 0.61-0.92) to have recently been tested than youth reporting a single partner. Importantly, the intervention was successful in reaching men with site specific success ranging from aOR 1.27 (95% CI 1.05-1.53) in South Africa to aOR 2.30 in Thailand (95% CI 1.85-2.84). Finally, across a diverse range of settings, higher education (aOR 1.67; 95% CI 1.42, 1.96), higher socio-economic status (aOR 1.21; 95% CI 1.08-1.36), and marriage (aOR 1.55; 95% CI 1.37-1.75) were all predictive of recent HTC, which did not significantly vary across study arm, site, gender or age category (18-24 vs. 25-32 years).

Fetal Growth Restriction Induces Heterogeneous Effects on Vascular Biomechanical and Functional Properties in Guinea Pigs (Cavia porcellus)

Aim: Fetal growth restriction (FGR) is associated with a variety of cardiometabolic diseases in adulthood which could involve remodeling processes of the vascular walls that could start in the fetal period. However, there is no consensus whether this remodeling affects in a similar way the whole vascular system. We aimed to determine the effects of FGR on the vasoactive and biomechanical properties of umbilical and systemic vessels in fetal guinea pigs.

Methods: FGR was induced by implanting ameroid occluders at mid-gestation in uterine arteries of pregnant guinea pigs, whilst the control group was exposed to simulated surgery. At the term of gestation, systemic arteries (aorta, carotid and femoral) and umbilical vessels were isolated to determine ex vivo contractile and biomechanical responses (stretch-stress until rupture) on a wire myograph, as well as opening angle and residual stresses. Histological characteristics in tissue samples were measured by van Gieson staining.

Results: Aorta and femoral arteries from FGR showed an increased in biomechanical markers of stiffness (p < 0.01), contractile capacity (p < 0.05) and relative media thickness (p < 0.01), but a reduced internal diameter (p < 0.001), compared with controls. There were no differences in the biomechanical properties of carotid and umbilical from control and FGR fetuses, but FGR umbilical arteries had a decreased contractile response to KCl (p < 0.05) along with a reduced relative media thickness (p < 0.05).

Conclusion: Altogether, these changes in functional, mechanical and morphological properties suggest that FGR is associated with a heterogeneous pro-constrictive vascular remodeling affecting mainly the lower body fetal arteries. These effects would be set during a pathologic pregnancy in order to sustain the fetal blood redistribution in the FGR and may persist up to adulthood increasing the risk of a cardiovascular disease.

Are there adverse consequences of quizzing during informed consent for HIV research?

INTRODUCTION

While quizzing during informed consent for research to ensure understanding has become commonplace, it is unclear whether the quizzing itself is problematic for potential participants. In this study, we address this issue in a multinational HIV prevention research trial enrolling injection drug users in China and Thailand.

METHODS

Enrolment procedures included an informed consent comprehension quiz. An informed consent survey followed.

RESULTS

525 participants completed the informed consent survey (Heng County, China¼255, Xinjiang, China¼229, Chiang Mai, Thailand¼41). Mean age was 33 and mean educational level was 8 yrs. While quizzing was felt to be a good way to determine if a person understands the nature of clinical trial participation (97%) and participants did not generally find the quiz to be problematic, minorities of respondents felt pressured (6%); anxious (5%); bored (5%); minded (5%); and did not find the questions easy (13%). In multivariate analysis, lower educational level was associated with not minding the quizzing (6e10 yrs vs 0e5 yrs: OR¼0.27, p¼0.03; more than 11 yrs vs 0e5 yrs: OR¼0.18, p¼0.03). There were also site differences (Heng County vs Xinjiang) in feeling anxious (OR¼0.07; p¼<0.01), not minding (OR¼0.26; p¼0.03), being bored (OR¼0.25; p¼0.01) and not finding the questions easy (OR¼0.10; p¼<0.01).

CONCLUSIONS

Quizzing during the informed consent process can be problematic for a minority of participants. These problems may be associated with the setting in which research takes place and educational level. Further research is needed to develop, test and implement alternative methods of ensuring comprehension of informed consent.

TRIAL REGISTRATION

clinicaltrials.gov number NCT00270257.

Comparison of methods to detect recent HIV type 1 infection in cross-sectionally collected specimens from a cohort of female sex workers in the Dominican Republic

Interest in estimating HIV-1 incidence using specimens obtained as part of cross-sectional surveys has led to the development of new methods to detect recent HIV-1 infection through the testing of a single anti-HIV-positive specimen. These assays are based on quantitative and qualitative differences in anti-HIV-1 antibodies between recent and long-standing infections. An ongoing vaccine preparedness study enrolled female sex workers in the Dominican Republic. Specimens from women found to be HIV positive at baseline were tested for recent HIV-1 infection using the detuned assay, avidity index, and BED-CEIA assay. An unweighted kappa statistic in pairwise comparisons was used to estimate the correlation of recent HIV-1 infection detection by the three methods. Nineteen (3.9%) of 482 women were positive for HIV-1 infection. The incidence of HIV infection was 1.4% [95% confidence interval (CI): 0.2, 5.3], 0.9%(95% CI: 0.1, 4.4), and 1.0%(95% CI: 0.1, 4.4) using detuned assay, avidity index, and BED-CEIA techniques, respectively. The overall agreement between both detuned assay and avidity index and detuned assay and BED-CEIA was 94%(kappa = 0.8, 95% CI; 0.3, 1.0). The correlation was highest between BED-CEIA and avidity index methods (100%; kappa = 1.0). All three methods performed similarly in detecting recent HIV-1 infection in this region dominated by clade B HIV-1 infection. Although incidence estimates were slightly higher using the detuned assay method, they were not significantly different. These assays may be of value in both clinical research and practice. The utility of individual assays for recent infection detection will depend upon operating characteristics, HIV-1 subtype limitations, and selection of appropriate assay cutoff values.

Characteristics of injection drug using parents who retain their children

While it is known that injection drug users (IDUs) often have their children removed or place them voluntarily, little is known about factors associated with whether IDU parents live with their children. We identified a community sample of 391 IDU parents with at least one child under age 14 (index IDU parents). For these IDU parents, 62% did not have any of their children under age 14 living with them. We assessed whether certain health factors, risk related behaviors, social indicators, and active drug use were related to whether children of IDUs were living with the index IDU parent. IDU parents who were living with their children were overwhelmingly more likely to be female, more likely to have health insurance, and engage in no-risk or low-risk drug practices, as compared to moderate/high-risk practices. Additionally, HIV negative and HIV positive asymptomatic parents were about three times more likely to be living with their children than HIV positive parents with clinical symptoms commonly seen among those suffering from HIV-related illnesses. HIV-related clinical symptoms, rather than HIV status per se, seem to be associated with retention of children.

Adoption of injection practices in heroin users in Guangxi Province, China

This preliminary study collected data from 326 heroin users in Guangxi Province, China, in 1997. Logistic regression analysis was performed to identify the risk factors for injection. Survival analysis identified factors independently associated with time from initiation of heroin use to adoption of injection. Four factors were independently associated with injection: number of friends who used heroin in the last year, duration of heroin use, dose of heroin consumed, and total number of times detoxified in drug treatment and rehabilitation centers. Only gender and duration of heroin use were independently associated with time to first injection. Median time to first injection was 11 months for males and 22 months for females. Median time to first injection varied by age. Median time to injection for those who used heroin for more than one year was 8.1 months; it was 19.1 months for on to five years of use, and 40.5 months for more than five years of use. This study's preliminary findings suggest that younger, more recent heroin users, and males are at increased risk of becoming injectors, a major risk behavior for HIV acquisition.

Modeling intervention efficacy for high-risk women. The WINGS Project

This study evaluates the effectiveness of two strategies--communication and condom skills training--for increasing condom-protected sex in a sample of 510 high-risk women ages 17 to 61. Baseline and 3- and 6-month postintervention interview data were gathered in three cities participating in a randomized trial of a six-session, group skill-building intervention. This analysis was conducted for the entire sample and for six subgroups categorized by age, single or multiple partners, and history of childhood sexual abuse. The dependent variable was the odds ratio of protected sex acts at each follow-up. Structural equation modeling was used to estimate effects for two intervention pathways. The pathway through condom skills increased the odds of protected sex for the intervention group (chi 2 difference = 35, df = 2, p < .05) as well as for all subgroups. The pathways through communication were significant for the intervention group (chi 2 difference = 23, df = 3, p < .05) but fully effective only for participants under 30 and participants who reported childhood sexual abuse. The effectiveness of both pathways diminished at 6 months. WINGS demonstrates that condom skills training can increase protected sex for a heterogeneous group of women. Further research needs to examine how such skill training translates into use of condoms by male partners. To increase the duration of intervention effects, booster sessions may need to be incorporated.

Effects of an HIV risk reduction project on sexual risk behavior of low-income STD patients

A 10-hour small-group informational and skill-building intervention was tested among patients (N = 472) attending publicly funded sexually transmitted disease clinics in Maryland, Georgia, and New Jersey. After completing a 90-minute interview concerning HIV risk behaviors, condom use self-efficacy and condom outcome expectancies, participants were randomized to either an intervention or a control condition. Participants in both conditions displayed significant reductions in unprotected encounters and number of partners and increases in condom use. No differences between treatment conditions were observed, indicating that the motivational effects of the interview may have been stronger than the effects of the intervention in this population.

Preventing HIV infection: the effects of community linkages, time, and money on recruiting and retaining women in intervention groups

Few studies have addressed recruitment and retention of participants in preventive interventions directed at human immunodeficiency virus (HIV), and these generally have not focused on women. In this study, part of the Women in Group Support (WINGS) project, we examine the experience of three sites in recruiting 444 high-risk women for a small group intervention to reduce risky sexual behavior. The intervention included six structured sessions, followed by a continuing series of client-focused, drop-in sessions. Incentives for participants included child care, food, and transportation tokens. Attendees at each structured session also received a cash incentive of $10-$20. Forty-six percent of the women were recruited from community sources, 35% from clinics, and 19% from drug programs. Across all recruitment sources, almost a third of the women reported having had a sexually transmitted disease (STD) in the past year, 88%-94% reported a risky male partner (who, they believed, had sex with other partners or with sex workers, was an injecting drug user, or was HIV positive), and 10%-36% reported trading sex for money or drugs. During 18 months of recruitment, each site averaged 34 screening interviews monthly to secure 8 eligible women a month who completed baseline interviews and reported for randomization. The average number of paid sessions attended by participants was five of six (83%). Average attendance at unpaid sessions was 1 of 12 (8%). Key facilitators to recruitment and retention included linkages with community agencies and monetary incentives. Our findings suggest that researchers and community service providers need to explore alternative strategies to paying women for attending group sessions (e.g., incorporating group interventions into existing program requirements) and balance these against the costs and recruitment effectiveness.

The association of herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and syphilis with HIV infection in young men in northern Thailand

To evaluate the association between sexually transmitted diseases that commonly may cause genital ulceration and prevalent and incident HIV infections, we conducted three case control studies in a cohort of 21-year-old male military conscripts in northern Thailand. The men were evaluated at baseline in 1991 and semiannually until their discharge 2 years later. Serologic evidence of infection with herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and HIV were more frequent at baseline in 83 men with a history of genital ulcer than in 97 men without such a history. Seropositivity to H. ducreyi (odds ratio [OR] = 3.46), HSV-2 (OR = 3.83), and syphilis (OR = 1.53) were more common in HIV-positive than HIV-negative men. Men (N = 45) who seroconverted to HIV while in the military were more often seropositive for H. ducreyi and HSV-2 before HIV seroconversion and also were more likely to seroconvert to HSV-2 and H. ducreyi during the same interval as their HIV seroconversion compared with men who remained HIV-negative. These data suggest that HSV-2 and H. ducreyi may be both markers for high-risk sexual behavior and risk factors for HIV infection among young men in Thailand.

Measurement of condom use self-efficacy and outcome expectancies in a geographically diverse group of STD patients

The aim of this project was to conduct an initial evaluation among sexually transmitted disease (STD) patients of the psychometric properties of two instruments: the National Institute of Mental Health (NIMH) multisite condom use self-efficacy scale and the NIMH multisite condom use outcome expectancy scale. The condom use self-efficacy scale was designed to measure one's degree of confidence in various aspects of condom use, whereas the outcome expectancy scale was designed to measure one's belief about the consequences of using condoms. Using a sample of 641 patients from five geographically diverse STD clinics in the eastern United States, initial reliability coefficients were computed. The alpha coefficient for the self-efficacy scale was .91 and for the outcome expectancy scale .88, indicating high internal consistency for both scales. Both scales were analyzed using common factor analytic procedures. Five factors emerged from the analysis of the self-efficacy scale and six factors from the analysis of the outcome expectancy scale. Reliability coefficients for the individual factors ranged from .76 to .86. Construct validity of each scale was assessed by hypothesis testing. As predicted, participants with higher levels of self-efficacy and more positive outcome expectancies were more likely to use condoms.

Reliability of partner reports of sexual history in a heterosexual population at a sexually transmitted diseases clinic

BACKGROUND

In epidemiologic research, information about sexual frequency and condom use is by necessity based on self-reports. This study investigated the reliability of self-reported sexual behavior in 162 heterosexual partnerships.

METHODS

Subjects were part of a larger study of condom use and sexually transmitted diseases (STD) conducted in two Baltimore STD clinics from 1990 to 1992. Partners were enrolled on the same day and were interviewed separately. Information about sexual activity and condom use was collected using a retrospective calendar for the 30 days before enrollment.

RESULTS

Participants were predominantly young, unmarried African-Americans. Based on Spearman's correlation coefficients and kappa statistics, the authors found only fair agreement (K = 0.43; r = 0.51) between partner reports of overall condom use for the 30-day period before the interview. Correlation coefficients ranged from 0.43 for frequency of any sexual activity to 0.56 for number of days on which vaginal intercourse occurred.

CONCLUSIONS

Partner agreement for condom use and frequency of sexual activity decreased as the recall period increased. Higher partner agreement was observed for questions with definite answers compared to the more open-ended sexual behavior questions. These findings indicate potential reporting bias in self-reports of sexual behavior in a population at high risk for STDs.

People and places: behavioral settings and personal network characteristics as correlates of needle sharing

Sharing of contaminated needles constitutes one of the primary modes of HIV transmission in the U.S. This study examined social and environmental factors as possible correlates of needle sharing in a sample of inner-city drug users in Baltimore, Maryland. Drug users' social context was assessed through an analysis of personal networks, and the environmental context of drug use was assessed through a delineation of injection settings. The 330 respondents participating in an HIV prevention study were administered two surveys an average of 5.2 months apart. An examination of the association of network characteristics at baseline and needle sharing at followup revealed that the factors of higher total network density, larger drug network size, and injecting at friends' residences were positively associated with reports of sharing needles that had been cleaned with bleach. Sharing of needles that had not been disinfected with bleach was positively associated with reports of injecting in semipublic areas (streets, rooftops, parks, cars, public bathrooms, and abandoned buildings). These data support ecological and resource models of needle sharing and suggest the potential utility of network-oriented strategies for reducing needle sharing among injecting drug users.

Using social network analysis to study patterns of drug use among urban drug users at high risk for HIV/AIDS

Few studies have examined the current social relationships of injecting drug users. This paper examines the structural and relationship characteristics of the social networks of injecting drug users, and the relation of social network characteristics to the HIV infection risk behavior of frequency of injecting heroin and cocaine. The study sample was comprised of 293 inner city injecting drug users in Baltimore, Maryland. Most participants (89%) reported at least one family member in their social network, and 44% listed their mother or step-mother in their network. Presence of family members in personal social networks was not related to patterns of drug use examined here; however, those who reported a partner in their personal social network injected significantly less often than those who did not report a partner. Network density and size of drug subnetworks were positively associated with frequency of drug injection. The results of this study suggest that social network analysis may be a useful tool for understanding the social context of HIV/AIDS risk behaviors.

Condom use to prevent incident STDs: the validity of self-reported condom use

BACKGROUND

Studies of sexual behavior and of interventions designed to reduce human immunodeficiency virus risk usually depend on self-report. Validation of self-reported condom use measures has not been previously reported in an urban population at high risk for sexually transmitted diseases and human immunodeficiency virus.

METHODS

A prospective cohort study was performed in subjects recruited from sexually transmitted disease clinics in Baltimore. At enrollment, a questionnaire was administered that assessed human immunodeficiency virus risk factors and sexually transmitted disease history, and used a retrospective calendar to assess sexual events and condom use over the previous 30 days. Clinical evaluation was performed for sexually transmitted diseases. At follow-up 3 months later, the same procedures were repeated. Incident sexually transmitted diseases at follow-up were defined as new culture or serologically documented diagnoses of gonorrhea, chlamydia, syphilis, or trichomoniasis.

RESULTS

In the 323 male and 275 female (total = 598) subjects who completed a follow-up visit, 21% reported using condoms for every act of sexual intercourse over the previous 30 days, 21% reported occasionally using condoms, and 59% reported not using condoms. At follow-up, 21% of subjects had new incident gonorrhea, chlamydia, syphilis, or trichomoniasis. Fifteen percent of the men who were "always" condom users had incident sexually transmitted diseases compared with 15.3% of "never users;" 23.5% of women who were "always" users had incident sexually transmitted diseases compared with 26.8% of "never" users.

CONCLUSIONS

In this high-risk population, self-reported condom use is not associated with lower sexually transmitted disease incidence. This finding suggests that self-reported condom use measures, even in a research setting, may be subject to substantial reporting bias.

Condom use to prevent incident STDs: the validity of self-reported condom use

BACKGROUND

Studies of sexual behavior and of interventions designed to reduce human immunodeficiency virus risk usually depend on self-report. Validation of self-reported condom use measures has not been previously reported in an urban population at high risk for sexually transmitted diseases and human immunodeficiency virus.

METHODS

A prospective cohort study was performed in subjects recruited from sexually transmitted disease clinics in Baltimore. At enrollment, a questionnaire was administered that assessed human immunodeficiency virus risk factors and sexually transmitted disease history, and used a retrospective calendar to assess sexual events and condom use over the previous 30 days. Clinical evaluation was performed for sexually transmitted diseases. At follow-up 3 months later, the same procedures were repeated. Incident sexually transmitted diseases at follow-up were defined as new culture or serologically documented diagnoses of gonorrhea, chlamydia, syphilis, or trichomoniasis.

RESULTS

In the 323 male and 275 female (total = 598) subjects who completed a follow-up visit, 21% reported using condoms for every act of sexual intercourse over the previous 30 days, 21% reported occasionally using condoms, and 59% reported not using condoms. At follow-up, 21% of subjects had new incident gonorrhea, chlamydia, syphilis, or trichomoniasis. Fifteen percent of the men who were "always" condom users had incident sexually transmitted diseases compared with 15.3% of "never users;" 23.5% of women who were "always" users had incident sexually transmitted diseases compared with 26.8% of "never" users.

CONCLUSIONS

In this high-risk population, self-reported condom use is not associated with lower sexually transmitted disease incidence. This finding suggests that self-reported condom use measures, even in a research setting, may be subject to substantial reporting bias.

Epidemiology / vaccine efficacy trials. "HIV Incidence in Adults in Northern Thailand"

According to an abstract submitted by the authors to the X International Conference on AIDS, held August 7-12, 1994, in Yokohama, Japan, "

OBJECTIVE

To measure the HIV-1 incidence, follow-up rates and high risk behaviors in cohorts of seronegative adults in northern Thailand.

METHODS

We screened cohorts of female commercial sex workers (CSWs), male STD clinic patients, Royal Thai Army (RTA) conscripts, and discharged RTA conscripts at baseline and q3 to 6 months for HIV infection by ELISA and WB and did interviews for high risk behavior, medical history, and STD cultures.

RESULTS

Of 1068 CSWs, 409 (38.3%) were HIV positive, and 396 HIV negative were enrolled in the study; follow-up at 6 months was 70.7% and 19 seroconverted, for an incidence of 12.8/100 person years. Of 1031 male STD patients, 164 (15.9%) were HIV positive, and 264 HIV negative (30.4%) were enrolled; follow-up at 6 months was 91.9% and 6 seroconverted, for an incidence of 4.92/100 person years. Of 969 RTA conscripts, 12.4% were HIV positive at baseline and 90% were followed at 6 months; 3 of 778 seroconverted, for an incidence of 0.87/100 person years. (Previous RTA cohorts have had an incidence of 3.4%/year). Among 380 men discharged from RTA, follow-up at 9 months was 81.8% and the incidence was 5.2/100 person years. Sample sizes required to show an HIV vaccine efficacy of 60%, with a power-.90, alpha-.05 varies from CSUs 644, STD patients 1456 to ex-RTA-1306.

CONCLUSIONS

Several populations in northern Thailand appear to have sufficiently high HIV-1 incidence and adequate follow-up for HIV vaccine efficacy trials and other preventive intervention trials.

The incidence of HIV-1 infections in village populations of northern Thailand

OBJECTIVES

To determine the age- and sex-specific prevalence of HIV-1 infection in a general ambulatory population in northern Thailand in 1990 and 1992, and the incidence of HIV-1 infections between 1990 and 1992.

DESIGN

Health fairs were held in five villages in Chiang Mai province in northern Thailand between December 1989 and January 1990 and again in January 1992. Participation of all village residents was encouraged. Villagers were offered testing for serological markers of hepatitis B virus (HBV) infection and free HBV vaccine was made available to susceptible individuals.

METHODS

Sera from the two surveys were linked and coded by demographic characteristics (age group and sex). Individual identifiers were removed and the sera tested for HIV-1 antibodies by enzyme-linked immunosorbent assay with Western blot confirmation.

RESULTS

In 1990, 21 out of 1161 (1.8%) individuals were HIV-1-seropositive; the infection rates were 3.3% in men and 0.5% in women. In 1992, 44 out of 956 (4.6%) individuals were HIV-1-seropositive. Among people included in both surveys the 2-year incidence was 2.0% in women and 4.1% in men (annual incidence, 1.0 and 2.05%, respectively); however, among men over the age of 14 years the 2-year incidence was 6.3%, whereas among women of this age the 2-year incidence was 1.8% (annual incidence, 3.15 and 0.9%, respectively). Among men, incident HIV-1 infections were common, even among those aged 50 years or more.

CONCLUSIONS

Infections with HIV-1 are disturbingly frequent and increasing among adult populations in semi-rural areas of northern Thailand. In order to contain further spread of the epidemic public-health strategies targeted to the general public, including those in rural areas, will be needed.

My place, your place, and no place: behavior settings as a risk factor for HIV-related injection practices of drug users in Baltimore, Maryland

Information is sparse on the social context of illicit drug injection behaviors and their relationship to HIV infection. This study examined relationships between injection settings, injecting with others, and HIV risk behaviors of sharing needles and not cleaning contaminated needles in a sample of 630 inner-city injecting drug users in Baltimore, MD. Through open-ended interviews, five primary settings of injection behavior were identified. These settings included one's own, friends' and mother's residence, shooting galleries, and semipublic areas. Most participants reported injecting in their own residence (92%) and friends' residence (86%) in the prior 6 months. In a multiple regression analysis, injecting at friends' residence, in shooting galleries, and in semipublic areas and frequency of injecting with others were significantly associated with frequency of sharing uncleaned needles, "slipping" (i.e., failure to disinfect shared needles), and not always cleaning used needles before injecting. Results suggest that interventions may benefit from targeting settings as well as behaviors to reduce the spread of HIV.

The relationships between sexual behavior, alcohol use, and personal network characteristics among injecting drug users in Baltimore, Maryland

BACKGROUND AND OBJECTIVES

Studies on the relationship between alcohol consumption and HIV-related risk behaviors report inconclusive and contradictory results.

GOAL OF THIS STUDY

This study sought to examine the relationship between drug and alcohol use, personal network characteristics, and sexual risk behaviors.

STUDY DESIGN

A sample of 290 injecting drug users in Baltimore, Maryland, were interviewed.

RESULTS

More than half the males and 28% of the females reported multiple partners within the prior 6 months, and 33% of the males reported exchanging money or drugs for sex. For males, heavy drinking was significantly associated with multiple partners, exchanging money or drugs for sex, and casual sex. The personal network characteristics of size and density, as measured by the percentage of network members who knew each other, were associated with sexual risk behaviors.

CONCLUSION

These results indicate that among injecting drug users in Baltimore, heavy drinkers, and those with larger, lower density personal networks have increased levels of sexual risk behaviors.

Comparative behavioral epidemiology of gonococcal and chlamydial infections among patients attending a Baltimore, Maryland, sexually transmitted disease clinic

Between April 1988 and May 1989, 400 males and 400 females attending a Baltimore, Maryland, sexually transmitted disease clinic were enrolled in a study evaluating and comparing behaviors associated with culture-proven gonococcal or chlamydial infection. The subjects were enrolled consecutively, and were all seen by the same clinician. Among participants of each sex, gonorrhea but not chlamydia was associated with increasing numbers of recent (the past 30 days) sexual partners. Compared with males with neither infection, factors independently associated with increased risk of gonorrhea included age less than 20 years (odds ratio (OR) = 1.93), the presence of genitourinary symptoms (OR = 8.07), and recent exposure to a new sexual partner (OR = 2.78); risk for chlamydial infection in males was associated with genitourinary symptoms (OR = 2.83) and was significantly reduced in those reporting multiple recent (OR = 0.19) or new (OR = 0.07) sexual partners. Among females, age less than 20 years was independently associated with gonococcal (OR = 1.86) and chlamydial (OR = 7.79) infections in comparison with females with neither infection. No other behavioral factors were associated with chlamydial infection for females in this study; however, having a regular sexual partner was associated with significantly elevated risk of gonorrhea (OR = 3.85), while the presence of genital tract symptoms was associated with diminished risk (OR = 0.29) for gonorrhea. These data suggest that there are differences in the behaviors associated with gonorrheal and chlamydial infections and that different strategies may be useful in efforts to control these infections.

Trends of HIV-1 risk reduction among initiates into intravenous drug use 1982-1987

To assess how injection practices may have changed during the course of the AIDS epidemic, active intravenous drug users (IVDUs) recruited from the community were asked to report year of first injection as well as specific details about the first 3 months after initial injection: frequencies of injection, using sterile needles, sharing needles and other equipment. For the analysis, the users were sorted into successive cohorts of initiation (by year of first injection), and tests for trends were completed using Mantel-Haenszel statistics. Among the 421 IVDUs who reported first injection between 1982 and 1987, the use of new sterile needles to self-administer drugs increased (p less than .05) along with its corollary behavior (i.e., using equipment one is sure that no one else had used before). Conversely, there was a decrease in the proportion of those who always used equipment previously used by another IVDU (p less than .05) and a decrease in the number of needle-sharing partners (p less than .01). Over the 6 years, heroin as first drug decreased and cocaine increased (p less than .01). Although these data are from a cross-sectional interview study, they suggest a shift toward lower risk practices among new IVDUs between 1982 and 1987. The shift from heroin to cocaine is compatible with other evidence on the cocaine epidemic.

Personality and emotional disorder in a community sample of migraine headache sufferers

To investigate whether individuals who suffer from chronic, severe headaches have more personality abnormalities or emotional disorders than their healthy counterparts, 162 young adults with classical migraine, ascertained by community survey, were compared to matched control subjects without migraine. On the General Health Questionnaire, the prevalence of psychological symptoms among the migraine subjects was 2.5 times the prevalence among the control subjects. The migraine sufferers also had significantly higher scores on the psychoticism (women only), neuroticism, and lie scales of the Eysenck Personality Questionnaire. Frequency of migraine attacks was not related to scores on any of the scales. These results suggest that classical migraine is associated with psychological abnormalities.

Pap testing intervals. Specialty differences in physicians' recommendations in relation to women's pap testing behavior

Using data from a survey of internists, family and general practitioners, and obstetricians and gynecologists, and of women in Maryland, this article examines congruence between physicians' recommendations and women's Papanicolaou (Pap) testing behavior. Both the specialty of the physicians and the age of the women are considered. The majority of all three physician specialties recommended annual Pap tests for all their patients. However, the internists and family or general practitioners were less likely to recommend annual Pap smears for their elderly patients than for their younger patients. Obstetrician-gynecologists were consistently more likely than the other specialties to recommend annual Pap tests, to send postcards to their patients reminding them to come in for Pap tests, and to view themselves as successful in inducing their patients to come in for routine Pap testing. Both the physicians and the women reported that elderly women were less likely than younger women to receive care from obstetrician-gynecologists. Women's reported Pap testing behavior indicated that they received Pap tests with far less frequency than the physicians recommended. Older age was related to less frequent Pap testing, while having a visit with an obstetrician-gynecologist was related to increased frequency. Findings indicate the need for education of physicians about methods of improving women's attendance for Pap testing and of women about the importance of routine Pap testing.