Juan Carlos de los Reyes

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This study examined the effectiveness of a combined counseling and case management behavioral intervention, using motivational interviewing strategies, in engaging Hispanic injection drug users in treatment and reducing drug use and injection-related HIV risk behaviors. Follow up data are presented on 440 (79.0%) of 557 randomized participants, 6 months(More)
Abstract. Second-order sufficient optimality conditions are established for the optimal control of semilinear elliptic and parabolic equations with pointwise constraints on the control and the state. In contrast to former publications on this subject, the cone of critical directions is the smallest possible in the sense that the second-order sufficient(More)
This study was designed to assess HIV risk behaviors, HIV seroprevalence, and tuberculosis (TB) infection in shooting gallery managers in Puerto Rico. The subjects were 464 injection drug users (IDUs), of whom 12.5% reported managing shooting galleries. The median frequency of drug injection was higher in shooting gallery managers than in nonmanagers. A(More)
OBJECTIVE We analyzed early sexual activity among Hispanic 14 to 15-year-old adolescents residing in a poor neighborhood in Puerto Rico. METHODS Information from a sample of 325 adolescents was collected from a randomized sample of community households. Logistic regression analysis was used to identify the variables that help explained adolescents' sexual(More)
This paper reports results of an analysis of the association between alcohol intoxication and injection and sexual HIV risk behaviors among 557 Hispanic heroin and cocaine injectors, not in treatment, who were recruited in poor communities in Puerto Rico. Subjects were part of a longitudinal prevention-intervention study aimed at reducing drug use and HIV(More)
This study was conducted to identify factors accounting for differences in health care and drug treatment utilization between Puerto Rican drug users residing in 2 separate locations. Survey findings from 334 drug users in Puerto Rico and 617 in New York City showed that those in Puerto Rico were 6 times less likely than their counterparts in New York to(More)
OBJECTIVES To examine the influence of knowledge of HIV serostatus on changes in risk behaviors among injecting drug users (IDU). PROCEDURES IDU were recruited through sampling conducted at street drug-selling areas. Of 374 participants, 88.8% consented to be HIV tested and returned for their test results, and 73.5% were relocated and interviewed 6 months(More)
This study evaluated the effectiveness of the first needle exchange program (NEP) established in Puerto Rico. The data for this study were collected during the first months of the NEP from July 1995 to March 1996 in 13 communities of the San Juan metropolitan area. Subjects were the participants of two modalities of the NEP: a mobile team and a(More)
Despite available strategies to prevent sex risk behaviours in Puerto Rico, heterosexual transmission of HIV continues to increase. Since 1990, heterosexual contact has been the fastest growing infection risk category among the island's general population, and the primary transmission route for women and children. To understand change in sex risk behaviours(More)
Needle sharing is one of the principal risk behaviors leading to HIV transmission among injection drug users (IDUs). Shooting galleries, a social context where IDUs rent, share, and borrow needles, are locations usually found near drug markets. This study, which interviewed 1,700 IDUs from May 1989 to June 1990, assesses sociodemographic characteristics and(More)