Barriers to Pharmacy-Based Syringe Purchase Among Injection Drug Users in Tijuana, Mexico: A Mixed Methods Study

Injection drug users (IDUs) may be denied purchase of sterile syringes even where purchase without a prescription is legal. This study examined barriers to over-the-counter (OTC) syringe purchase among IDUs in Tijuana, Mexico. A quantitative survey and subsequent focus groups were used to quantify barriers to purchase, identify their correlates and provide in-depth exploration of syringe purchase experiences. Of 627 IDUs, 81% purchased a syringe in the past 6 months and 16% were refused or overcharged. Factors independently associated with refusal/overcharging were homelessness, receptive syringe sharing, >5 uses per syringe, and number of lifetime abscesses. Few pharmacies sold syringes to IDUs, who adapted by limiting purchase attempts to pharmacies known to sell syringes consistently. Failed purchases occurred when drug withdrawal required purchase at unusual times or locations, often following release from jail. IDUs reported syringe sharing, syringe reuse, and searching through unsecured medical waste for syringes in response to failed purchase attempts. Interventions to expand OTC syringe sales to IDUs, particularly near detention facilities, will facilitate safer injection practices

Meta-analysis of the BDNF Val66Met polymorphism in major depressive disorder: Effects of gender and ethnicity

Item does not contain fulltextBrain-derived neurotrophic factor (BDNF) is a nerve growth factor that has antidepressant-like effects in animals and may be implicated in the etiology of mood-related phenotypes. However, genetic association studies of the BDNF Val66Met polymorphism (single nucleotide polymorphism rs6265) in major depressive disorder (MDD) have produced inconsistent results. We conducted a meta-analysis of studies comparing the frequency of the BDNF Val66Met-coding variant in depressed cases (MDD) and nondepressed controls. A total of 14 studies involving 2812 cases with DSM-III or -IV defined MDD and 10 843 nondepressed controls met the inclusion criteria. Analyses were stratified either by gender or ethnicity (Asian and Caucasian) because MDD is more prevalent in women and in Caucasians and because BDNF allele frequencies differ by ethnicity. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were provided for allelic analyses (Met versus Val), as well as for genotypic analyses (Met/Met and Val/Met versus Val/Val). In the total sample, the BDNF Val66Met polymorphism was not significantly associated with depression. However, the gender stratified analyses revealed significant effects in both the allelic and genotypic analyses in men (ORMET, 95% CI; 1.27 (1.10–1.47); ORMET/MET, 95% CI; 1.67 (1.19–2.36)). Stratification according to ethnicity did not show significant effects of the Val66Met polymorphism on MDD. Our results suggest that the BDNF Val66Met polymorphism is of greater importance in the development of MDD in men than in women. Future research into gender issues will be of interest.12 p

Search for lensing signatures in the gravitational-wave observations from the first half of LIGO-Virgo's third observing run

We search for signatures of gravitational lensing in the gravitational-wave signals from compact binary coalescences detected by Advanced LIGO and Advanced Virgo during O3a, the first half of their third observing run. We study: 1) the expected rate of lensing at current detector sensitivity and the implications of a non-observation of strong lensing or a stochastic gravitational-wave background on the merger-rate density at high redshift; 2) how the interpretation of individual high-mass events would change if they were found to be lensed; 3) the possibility of multiple images due to strong lensing by galaxies or galaxy clusters; and 4) possible wave-optics effects due to point-mass microlenses. Several pairs of signals in the multiple-image analysis show similar parameters and, in this sense, are nominally consistent with the strong lensing hypothesis. However, taking into account population priors, selection effects, and the prior odds against lensing, these events do not provide sufficient evidence for lensing. Overall, we find no compelling evidence for lensing in the observed gravitational-wave signals from any of these analyses

Search for Lensing Signatures in the Gravitational-Wave Observations from the First Half of LIGO-Virgo's Third Observing Run

We search for signatures of gravitational lensing in the gravitational-wave signals from compact binary coalescences detected by Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) and Advanced Virgo during O3a, the first half of their third observing run. We study: (1) the expected rate of lensing at current detector sensitivity and the implications of a non-observation of strong lensing or a stochastic gravitational-wave background on the merger-rate density at high redshift; (2) how the interpretation of individual high-mass events would change if they were found to be lensed; (3) the possibility of multiple images due to strong lensing by galaxies or galaxy clusters; and (4) possible wave-optics effects due to point-mass microlenses. Several pairs of signals in the multiple-image analysis show similar parameters and, in this sense, are nominally consistent with the strong lensing hypothesis. However, taking into account population priors, selection effects, and the prior odds against lensing, these events do not provide sufficient evidence for lensing. Overall, we find no compelling evidence for lensing in the observed gravitational-wave signals from any of these analyses