Prevalence and Correlates of Injecting with Visitors from the United States Among People Who Inject Drugs in Tijuana, Mexico.

Cross-border infectious disease transmission is a concern related to drug tourism from the U.S. to Mexico. We assessed this risk among people who inject drugs (PWID) in Tijuana, Mexico. We measured the prevalence and identified correlates of injecting with PWID visiting from the U.S. among PWID in Tijuana using univariable and multivariable logistic regression. Of 727 participants, 18.5% injected during the past 6 months in Mexico with U.S. PWID described mostly as friends (63%) or acquaintances (26%). Injecting with U.S. PWID was independently associated with higher education [adjusted odds ratio (aOR) = 1.13/year], deportation from the U.S. (aOR = 1.70), younger age at first injection (aOR = 0.96/year), more lifetime overdoses (aOR = 1.08), and, in the past 6 months, backloading (aOR = 4.00), syringe confiscation by the police (aOR = 3.02) and paying for sex (aOR = 2.98; all p-values < 0.05). Nearly one-fifth of PWID in Tijuana recently injected with U.S. PWID, and their reported risk behaviors could facilitate cross-border disease transmission.

Measuring improvement in knowledge of drug policy reforms following a police education program in Tijuana, Mexico.

BACKGROUND: Mexico's 2009 "narcomenudeo reform" decriminalized small amounts of drugs, shifting some drug law enforcement to the states and mandating drug treatment diversion instead of incarceration. Data from Tijuana suggested limited implementation of this harm reduction-oriented policy. We studied whether a police education program (PEP) improved officers' drug and syringe policy knowledge, and aimed to identify participant characteristics associated with improvement of drug policy knowledge. METHODS: Pre- and post-training surveys were self-administered by municipal police officers to measure legal knowledge. Training impact was assessed through matched paired nominal data using McNemar's tests. Multivariable logistic regression was used to identify predictors of improved legal knowledge, as measured by officers' ability to identify conceptual legal provisions related to syringe possession and thresholds of drugs covered under the reform. RESULTS: Of 1750 respondents comparing pre- versus post training, officers reported significant improvement (p < 0.001) in their technical understanding of syringe possession (56 to 91%) and drug amounts decriminalized, including marijuana (9 to 52%), heroin (8 to 71%), and methamphetamine (7 to 70%). The training was associated with even greater success in improving conceptual legal knowledge for syringe possession (67 to 96%) (p < 0.001), marijuana (16 to 91%), heroin (11 to 91%), and methamphetamine (11 to 89%). In multivariable modeling, those with at least a high school education were more likely to exhibit improvement of conceptual legal knowledge of syringe possession (adjusted odds ratio [aOR] 2.6, 95% CI 1.4-3.2) and decriminalization for heroin (aOR 2.7, 95% CI 1.3-4.3), methamphetamine (aOR 2.2, 95% CI 1.4-3.2), and marijuana (aOR 2.5, 95% CI 1.6-4). CONCLUSIONS: Drug policy reform is often necessary, but not sufficient to achieve public health goals because of gaps in translating formal laws to policing practice. To close such gaps, PEP initiatives bundling occupational safety information with relevant legal content demonstrate clear promise. Our findings underscore additional efforts needed to raise technical knowledge of the law among personnel tasked with its enforcement. Police professionalization, including minimum educational standards, appear critical for aligning policing with harm reduction goals.

Condom use among female sex workers and their non-commercial partners: effects of a sexual risk intervention in two Mexican cities.

The purpose of this study was to examine whether a brief behavioural intervention promoting condom use among female sex workers (FSWs) and their clients had the added benefit of increasing condom use among FSWs and their steady, non-commercial partners (e.g. husbands, boyfriends). Participants were 362 FSWs, aged ≥18 years, living in Tijuana or Ciudad Juarez, Mexico, who received a behavioural intervention to promote condom use with clients. Repeated-measures negative binomial regression was used to assess FSWs' condom use with steady partners versus clients across time. Results showed that FSWs engaged in unprotected sex with steady partners more than with their clients, and that the intervention changed FSWs' condom use with clients but not their steady partners. HIV-prevention interventions for FSWs should promote consistent condom use across partner type. Targeting couples rather than individuals may also be necessary.

Allicin-induced decrease in formation of fatty streaks (atherosclerosis) in mice fed a cholesterol-rich diet.

BACKGROUND: Garlic (Allium sativum) has been considered to exhibit therapeutic features for many years. The effects of garlic on levels of serum lipids and on atherosclerosis have been investigated extensively. We have previously demonstrated that allicin, an active component of garlic, exerts a beneficial effect on lipid profile in hyperlipidemic rabbits. OBJECTIVE: To investigate the effects of allicin on formation of fatty streaks (atherosclerosis) and lipid profile in mice. METHODS: Allicin was extracted from garlic and kept in a buffer citrate solution at 4 degrees C. Sixty C57BL/6 mice were fed Paigen diet (17% fat, 1.25% cholesterol) for 15 weeks. Thirty randomly selected animals were administered allicin solution (9 mg/kg) and 30 were administered placebo. Blood lipid profile was evaluated five times during the study. At the end of the 15-week period, the animals were killed and the aortic sinus was evaluated for formation of fatty streaks (atherosclerosis). RESULTS: We observed no statistically significant differences between blood lipid profiles of groups. Microscopic evaluation of aortic sinus formation of fatty streaks (atherosclerosis), however, showed that values for mice in the allicin-treated group were significantly lower: areas of formation of fatty streaks (atherosclerosis) were 13,440 +/- 3310 and 23,410 +/- 3723 micron 2, respectively, for allicin-treated and control mice (means +/- SEM; P = 0.023). CONCLUSIONS: These results indicate that allicin reduces formation of fatty streaks (atherosclerosis) in hyperlipidemic mice. These changes do not seem to occur through an alteration in blood lipid profile.

Ribozyme catalysis from the major groove of group II intron domain 5.

The most highly conserved nucleotides in D5, an essential active site component of group II introns, consist of an AGC triad, of which the G is invariant. To understand how this G participates in catalysis, the mechanistic contribution of its functional groups was examined. We observed that the exocyclic amine of G participates in ground state interactions that stabilize D5 binding from the minor groove. In contrast, each major groove heteroatom of the critical G (specifically N7 or O6) is essential for chemistry. Thus, major groove atoms in an RNA helix can participate in catalysis, despite their presumed inaccessibility. N7 or O6 of the critical G could engage in critical tertiary interactions with the rest of the intron or they could, together with phosphate oxygens, serve as a binding site for catalytic metal ions.

Remarkable morphological variability of a common RNA folding motif: the GNRA tetraloop-receptor interaction.

One of the most common RNA tertiary interactions involves the docking of GNRA hairpin loops into stem-loop structures on other regions of RNA. Domain 5 of the group II intron interacts with Domain 1 through such an interaction, which has been characterized thermodynamically and kinetically for the ai5g intron. Using this system, it was possible to test the morphological tolerances of the GNRA tetraloop involved in tertiary interactions. The data presented herein show that a GNRA tetraloop can still participate in tertiary interaction after being physically cut at any phosphodiester linkage within the loop. The "nicked tetraloop" can be expanded by many nucleotides in either direction and the covalently continuous loop can also be expanded without loss of interaction energy. In the context of the nicked tetraloop, the second nucleotide of the tetraloop sequence can be completely deleted without loss of function. By examining radical alterations in tetraloop structure, this study helps define the minimal sequence and structural requirements of a GNRA motif involved in long-range tertiary interaction. It shows that "tetraloop"-like structures capable of forming tertiary interactions can be imbedded in unexpected contexts, such as internal loops and apparently open structure within RNA. It demonstrates that pentaloops and hexaloops can form the same type of interaction, with almost equal affinity, as a tetraloop. Taken together, these data suggest a more generic term for the GNRA tetraloop-receptor interaction: It is proposed herein that the term "GNRA tetraloop" be replaced by "GNn/RA", where n represents a variable number of nucleotides and / indicates that the loop can be divided and interrupted by other sequences.

Catalytic role of 2'-hydroxyl groups within a group II intron active site.

Domain 5 is an essential active-site component of group II intron ribozymes. The role of backbone substituents in D5 function was explored through synthesis of a series of derivatives containing deoxynucleotides at each position along the D5 strand. Kinetic screens revealed that eight 2'-hydroxyl groups were likely to be critical for activity of D5. Through two separate methods, including competitive inhibition and direct kinetic analysis, effects on binding and chemistry were distinguished. Depending on their function, important 2'-hydroxyl groups lie on opposite faces of the molecule, defining distinct loci for molecular recognition and catalysis by D5.