Biomedical subjects

J Galbraith

Publications and source records attributed to J Galbraith.

At least 19 recordsLinked to original sources

PubMed1999

TNF recruits TRADD to the plasma membrane but not the trans-Golgi network, the principal subcellular location of TNF-R1.

The subcellular localization of TNF-R1 to the Golgi apparatus, initially observed in endothelial cells, has been confirmed using transfection of bovine aortic endothelial cells with a human TNF-R1 expression plasmid. The subcellular interactions of TNF-R1 and the TRADD (TNFR-associated death domain protein) adaptor protein have been analyzed in the human monocyte cell line U937 and the human endothelial cell line ECV304 by confocal immunofluorescence microscopy and by Western blot analysis of fractionated cell extracts. In untreated cells, in which TNF-R1 is found on the cell surface but principally localizes to the trans-Golgi network, TRADD is concentrated in the cis- or medial-Golgi region, but separates from the Golgi during cell fractionation. Coimmunoprecipitation studies have shown that TRADD binds to TNF-R1 within 1 min of TNF treatment in a cell fraction-containing plasma membrane. This association is followed by a gradual dissociation, which is prevented if receptor-mediated endocytosis is inhibited by hypertonic medium. In contrast, no association is detected between TRADD and TNF-R1 in the Golgi in response to exogenous TNF at any time examined. These results suggest that although TNF-R1 is predominantly a Golgi-associated protein and TRADD also localizes to the Golgi region, exogenous TNF causes TRADD to bind to TNF-R1 only at the plasma membrane.

Animals↗

PubMed1998

Drug trafficking and drug use among urban African-American adolescents: a causal analysis.

OBJECTIVE: To test the hypothesis that involvement in drug trafficking leads to illicit drug use among urban African-American adolescents. METHODS: Self-reports of substance use, illicit drug use, and drug trafficking were obtained at baseline and every 6 months for 24 months from 383 African-American early adolescents. Transitions between involvement in drug trafficking and illicit drug use over time were examined. Path analysis was conducted to examine the causal relation between drug trafficking and drug use. RESULTS: Among the 35 youth who were initially involved only in drug trafficking, 22 (67%) subsequently used illicit drugs. Of the 53 youth who were initially involved only in illicit drug use, only 19 (42%) continued using drugs at later waves (p < 0.05). Path analysis revealed that baseline drug trafficking had a strong effect on subsequent drug trafficking and drug use, whereas baseline drug use did not have an effect on subsequent drug use or drug trafficking. CONCLUSIONS: Initiation of drug trafficking by adolescents appears to lead to sustained involvement in drug-related activities, including continued drug trafficking and drug use. By contrast, initiation of drug use does not necessarily lead to continued involvement in drug-related behaviors.

Adolescent↗

PubMed1997

Evolution of risk behaviors over 2 years among a cohort of urban African American adolescents.

OBJECTIVE: To examine the evolution of risk behaviors over 2 years among a community-based cohort of low-income African American preadolescents and young adolescents enrolled in a randomized trial of an acquired immunodeficiency syndrome risk reduction intervention. DESIGN: Longitudinal, community-based cohort. SETTING: Nine recreation centers serving 3 public housing developments. SUBJECTS: Three hundred eighty-three African American youths aged 9 through 15 years at baseline. INTERVENTIONS: Frequency distributions, chi 2 analyses, and regression analyses regarding 10 risk behaviors were conducted. To assess whether a specific risk behavior or its protective (nonrisk) behavioral analogue, composing a risk-nonrisk behavioral complex (eg, was sexually active and was sexually abstinent or used drugs and refrained from drugs), was stable over time, kappa values were determined for the 10 risk-nonrisk behavioral complexes. MAIN OUTCOME MEASURES: Instrument assessing risk/ behaviors administered at baseline and every 6 months aurally and visually via talking computer. RESULTS: The prevalence of sexual intercourse, cigarette smoking, alcohol consumption, and drug use increased notably over time. Drug use increased from a 6-month cumulative prevalence of 7% at baseline to 27% at the 24-month follow-up (P < .001). Cumulatively over the 2-year study interval, 81% of youths had engaged in fighting, 58% had engaged in sexual intercourse, and from 33% to 40% had engaged in truancy, knife or bat carrying or both, alcohol consumption, drug use, and cigarette smoking. All of the risk-nonrisk behavioral complexes except weapon carrying were stable during the semiannual assessment intervals. Fighting (kappa = 0.22, P < .01), sexual intercourse (kappa = 0.33, P < .001), alcohol consumption (kappa = 0.21, P < .001), and unprotected sexual intercourse (kappa = 0.34, P < .05) were stable for 2 years. Six risk-nonrisk behavioral complexes were stable for the 2-year interval among youths aged 13 through 15 years at baseline, while only 2 risk-nonrisk behavioral complexes were stable among younger youths. The intervention seemed to affect the stability of 4 risk behaviors: truancy, drug use, unprotected sexual intercourse, and, possibly, fighting. For unprotected sexual intercourse, this intervention effect seemed to be due to stabilization of nonparticipation in risky behavior. Intervention youths were less likely to adopt a risk behavior (ie, engage in it for > or = 2 risk assessment periods) than control youths, but they were not less likely to experiment with a risk behavior. CONCLUSIONS: There is evidence that although the prevalence of risk behaviors does change with age, most risk-nonrisk behavioral complexes seem to be relatively stable over time and stability may increase with time. Risk reduction interventions seem to decrease risk adoption, stabilize nonrisk behaviors, and possibly destabilize risk behavior.

Acquired Immunodeficiency Syndrome↗

PubMed1997

Effectiveness of the 40 adolescent AIDS-risk reduction interventions: a quantitative review.

OBJECTIVE: (1) To review evaluations of Acquired Immunodeficiency Syndrome (AIDS) prevention interventions targeting adolescents to determine whether these efforts have been effective in reducing risk behaviors. (2) To examine the relation between intervention design issues and outcomes measures. METHOD: A systematic review of five electronic databases and hand-searches of 11 journals, were undertaken for articles published from January 1983 through November 1995 that reported evaluations of adolescent AIDS risk-reduction interventions conducted in the United States. Outcomes examined include: improved attitudes about AIDS risk and protective behaviors, increased intention to abstain from sexual intercourse or to use condoms, and reduced sexual risk behaviors. RESULTS: Forty studies that met preestablished inclusion criteria were found. For each outcome assessed, a majority of studies found a positive intervention impact (88% of studies assessing changes in knowledge; 58% changes in attitude, 60% changes in intention to use condoms, 73% in condom use, and 64% in decreasing number of sexual partners). Interventions that demonstrated an increase in intention to use a condom were significantly more likely to be theory-based than those that did not show any significant changes in intention (100% vs. 0%, p = .048). Interventions that increased condom use and decreased the number of sexual partners were longer in duration than those that did not improve these outcomes. CONCLUSIONS: AIDS risk reduction interventions can be effective in improving knowledge, attitudes, and behavioral intentions and in reducing risk practices. The positive relationship between improved outcomes and several elements of intervention design underscores the need for increased focus on intervention design in future studies.

Acquired Immunodeficiency Syndrome↗

PubMed1996

Sexually transmitted diseases, human immunodeficiency virus, and pregnancy prevention. Combined contraceptive practices among urban African-American early adolescents.

OBJECTIVE: To evaluate the success of efforts to educate youth not only to use prescription contraceptives to avoid pregnancy, but also to use condoms to avoid sexually transmitted diseases, including infection with the human immunodeficiency virus. METHODS: Longitudinal study of 383 African-American youth aged 9 to 15 years enrolled in a randomized, controlled trial of an acquired immunodeficiency syndrome (AIDS) risk reduction intervention. Data about contraceptive practices were obtained at baseline and 6, 12, and 18 months later using a culturally and developmentally appropriate risk assessment tool administered with "talking" computers (Macintosh, Apple Computer Inc, Cupertino, Calif). RESULTS: Approximately three fourths of sexually active youth used some form of contraception in each 6-month round, with almost half of the youth using combinations of contraceptives. Among all youth at baseline and among control youth throughout the study, more than half used condoms and more than two thirds who used oral contraceptives also used condoms. Receipt of an AIDS education intervention was associated with use of more effective contraceptive practices (eg, condoms and another prescription or nonprescription method of birth control). After receiving the intervention, more than 80% of the youth who used oral contraceptives also used condoms. Contraceptive practices showed considerable stability. Knowledge about AIDS was positively associated with use of more effective contraceptive methods. CONCLUSIONS: Many youth are using condoms and prescription birth control simultaneously, and these use rates can be increased through AIDS education interventions.

Adolescent↗

PubMed1996

A randomized, controlled effectiveness trial of an AIDS prevention program for low-income African-American youths.

BACKGROUND: Some interventions to reduce the risk of the acquired immunodeficiency syndrome (AIDS) that target youths have resulted in short-term increases in self-reported condom use. However, long-term intervention effects have not been assessed. STUDY QUESTION: Can a theoretically and culturally based, AIDS-risk reduction intervention delivered to naturally formed peer groups increase self-reported condom use among African-American early adolescents at 6 and 12 months of follow-up? METHOD: A randomized, controlled trial of a community-based intervention delivered in eight weekly sessions involved 76 naturally formed peer groups consisting of 383 (206 intervention and 177 control) African-American youths 9 to 15 years of age. A theory-based, culturally and developmentally tailored instrument that assessed perceptions, intentions, and self-reported sexual behaviors was administered to all subjects at baseline (preintervention) and 6 and 12 months later. RESULTS: At baseline, 36% of youths were sexually experienced, and by 12 months of follow-up, 49% were sexually experienced. Self-reported condom use rates were significantly higher among intervention than control youths (85% vs 61%; P<.05) at the 6-month follow-up. However, by 12 months, rates were no longer significantly higher among intervention youths. The intervention impact at 6 months was especially strong among boys (85% vs 57%; P<.05) and among early teens (13 to 15 years old) (95% vs 60%; P<.01). Self-reported condom use intention was also increased among intervention youths at 6 months but not at 12 months. Some perceptions were positively affected at 6 months, but the change did not persist at 12 months. CONCLUSIONS: High rates of sexual intercourse underscore the urgent need for effective AIDS-risk reduction interventions that target low-income urban, African-American preteens and early teens. A developmentally and culturally tailored intervention based on social-cognitive theory and delivered to naturally formed peer groups recruited from community settings can increase self-reported condom use. The strong short-term improvements in behaviors and intentions followed by some relapse over longer periods argue for a strengthened program and research focus on sustainability.

Acquired Immunodeficiency Syndrome↗

PubMed1996

Longitudinal stability and predictability of sexual perceptions, intentions, and behaviors among early adolescent African-Americans.

PURPOSE: To assess the stability and predictability of perceptions, intentions, and behaviors regarding intended sexual intercourse and condom use. METHODS: One hundred and nineteen African-American youth aged 9-15 years living in urban public housing provided information at baseline and 6 months later using a theory-based and culturally- and developmentally-tailored instrument assessing perceptions, intentions, and sexual behaviors. RESULTS: Over the 6-month study interval, individual behaviors, intentions, and perceptions demonstrated considerable stability. Intentions regarding sexual intercourse in the next half-year were predictive of subsequent coitus among the entire cohort and among the subset who were virgins at baseline. Youth who thought it likely that they would be sexually-active in the next 6 months were at significantly elevated risk of doing so, compared to youth who were uncertain or thought coitus unlikely. However, intentions regarding future coitus among the subset of youth who were sexually-experienced at baseline were not predictive of future coital behavior. CONCLUSIONS: These data suggest that social cognitive behavioral models that incorporate intentions and perceptions are appropriate as the theoretical basis for interventions targeting these young adolescents.

Adolescent↗

PubMed1996

Design issues addressed in published evaluations of adolescent HIV-risk reduction interventions: a review.

OBJECTIVE: This study was conducted to determine: (1) issues in intervention design that have been addressed in behavioral interventions targeting human immunodeficiency virus (HIV)-risk behaviors among adolescents; (2) specific choices made in intervention design; (3) historic changes in the likelihood that issues in intervention design will be addressed; and (4) if an association exists between quality of evaluation design and the number of intervention design issues addressed. DESIGN: Literature search employing five electronic databases and 11 journals for articles published from January 1983 through December 1993 reporting evaluations of adolescent HIV-risk reduction interventions. MAIN OUTCOMES MEASURES: The frequency with which 12 issues in intervention design were addressed: basing the intervention on a theory of behavioral change; specifying a target population; involving the targeted community in the formulation of the intervention; addressing developmental issues; providing facts; strengthening interpersonal skills; describing the media (format) for delivering the intervention; specifying potentially relevant characteristics of the interventionists; describing the duration of the intervention; providing boosters; pilot testing the intervention; and including other potentially augmentative elements. RESULTS: Twenty-eight published intervention articles were included in these analyses. The median number of intervention design issues addressed in any study was six (range three to nine), although this number increased significantly over time (p < .01). There was substantial variability in the frequency with which each individual design issue was addressed, with some design issues (e.g., inclusion of specific facts and the description of the channel employed) being addressed in all studies. Other design issues were addressed in less than one-quarter of studies [e.g., basing the intervention on a theory of behavioral change (18%) and addressing developmental issues (21%)]. The targeted community was involved in one-third of studies. More recent studies and studies employing a randomized evaluation design with both preintervention and postintervention assessments addressed more intervention design issues than did earlier studies and studies employing other evaluation designs (p = .01 and p = .03, respectively). CONCLUSION: The majority of published adolescent HIV-risk reduction studies have not addressed important issues in intervention design. However, more recent studies and studies employing a strong evaluation design have addressed a greater number of these issues. Frameworks to guide intervention efforts (e.g., to serve as "practice guidelines") are needed to allow for both accurate replication and meaningful comparison of differing intervention approaches.

Adolescent↗

PubMed1996

Challenges and rewards of involving community in research: an overview of the "Focus on Kids" HIV Risk Reduction Program.

Acquired immunodeficiency syndrome (AIDS) continues to be a significant concern for adolescents, especially in minority populations. There is a scarcity of knowledge of the cultural context of sexual behavior in this age group and the influences that lead to early initiation of sex and unsafe sex. Few efforts targeting young adolescents have been community based, although there has been an increased awareness of the need for such research and intervention programs. Four key processes have been defined in gaining community participation in health education programs: (a) defining the community and reaching the community; (b) recognizing tensions among service, research, and community participation; (c) involving community residents; and (d) considering cultural differences in a community. These processes are used to describe the "Focus on Kids" project, a human immunodeficiency virus (HIV) risk reduction intervention that resulted in significant increases in condom use demonstrated by a randomized controlled trial.

Adolescent↗

PubMed1996

Similarity of risk and protective behaviors among African-American pre- and early adolescent members of naturally occurring friendship groups.

To determine whether self-reported risk and protective behaviors, expectations, and attitudes are more similar among African-American early adolescents within a community-based friendship group than across groups, a cross-sectional study was conducted among 382 African-American youth 9 through 15 years of age forming 76 community-based groups of 3 through 10 same-gender friends. Each member of the friendship group reported his/her own past involvement in nine risk behaviors (sexual intercourse, substance abuse, drug-trafficking, and other delinquent activities) and two protective behaviors (high academic performance and regular church attendance) and their expectations and feelings regarding several of these behaviors. Intraclass correlation coefficients were calculated overall and by gender and age. Members were generally more similar within friendship groups than across groups with regard to several risk behaviors and expectations including sexual intercourse and drug-trafficking. Particularly striking was the similarity among members of "junior" friendship groups (e.g., median age of youth < 11 years) of both risk and protective behaviors and expectations. The finding of enhanced similarity of risk behaviors and expectations among members within groups suggests that intervention delivery through community-based friendship groups may be a useful approach for risk prevention efforts targeting pre-adolescent African-American youth living in low-income settings.

Achievement↗

PubMed1995

Development of a culturally, theoretically and developmentally based survey instrument for assessing risk behaviors among African-American early adolescents living in urban low-income neighborhoods.

The creation of developmentally and culturally appropriate data-gathering instruments is necessary as health researchers and interventionists expand their investigations to community-based minority adolescent populations. The creation of such instruments is a complex process, requiring the integration of multiple data-gathering and analytic approaches. Recent efforts have delineated several issues to be considered in survey design for minority populations: community collaboration; problem conceptualization; application of the presumed model of behavioral change; and dialect and format of delivery. This paper describes the process of creating a culturally and developmentally appropriate, theoretically grounded instrument for use in monitoring the impact of an AIDS educational intervention on the behavior and health outcomes of urban African-American pre-adolescents and early adolescents. Three phases of research were involved: preliminary (and ongoing) ethnographic research including extensive participant observation, as well as, focus group and individual interviews with 65 youths; construction and testing of the preliminary instrument involving two waves of pilot testing (N1 = 57; N2 = 45); and, finalization of the instrument including reliability testing and assessment of tool constructs and selection of the mode of delivery (involving 2 additional waves of pilot testing (N3 = 91; N4 = 351). The essential role played by the community in all phases of instrument development is underscored.

Adolescent↗

PubMed1994

Anal intercourse among preadolescent and early adolescent low-income urban African-Americans.

OBJECTIVE: The purpose of this study, which was conducted as part of a larger study on adolescent risk behaviors, was to determine the frequency of anal intercourse among preadolescent and early adolescent youths. DESIGN: Survey. SUBJECTS: Three hundred fifty-one low-income urban African-American youths aged 9 to 15 years. MAIN OUTCOME MEASURES: A questionnaire assessing self-reported acquired immunodeficiency syndrome-risk behaviors was administered via a "talking" computer. The outcome measure was anal intercourse. RESULTS: Of the 137 youths (39%) who had engaged in any sexual intercourse (vaginal or anal), 50 (36%) had engaged in anal intercourse, including 41 (35%) sexually active boys and nine (43%) sexually active girls. Youths who had engaged in anal intercourse were significantly more likely to report having been sexually molested and having engaged in several delinquent behaviors than were virgins or youths who had engaged in coitus only. CONCLUSIONS: Efforts at preventing acquired immunodeficiency syndrome that target low-income urban African-American early adolescents should include the high-risk nature of anal intercourse.

Acquired Immunodeficiency Syndrome↗

PubMed1994

Social influences on the sexual behavior of youth at risk for HIV exposure.

OBJECTIVES: Adolescents are increasingly at risk for infection with human immunodeficiency virus (HIV) and other sexually transmitted diseases, especially in poor urban minority communities. To aid the design of interventions in these communities, this study investigated the role of knowledge, attitudes, perceived parental monitoring, and peer behavior in the onset and progression of sexual behavior in children at risk for exposure to HIV. METHODS: A computerized personal interview was administered to 300 African-American 9- to 15-year-old children living in six public housing developments in a large US city. RESULTS: Although children's knowledge about the hazards of sex increased with age, their sexual activity also increased (from 12% sexually experienced at 9 years of age to more than 80% experienced at 15 years of age). Parental monitoring appeared able to influence sexual activity. However, the perceived behavior of friends was associated with the rate at which sexual activity progressed with age and the degree to which condom use was maintained with age. CONCLUSIONS: The early onset and prevalence of sexual behavior and the importance of peer group influence call for early interventions that simultaneously influence the parents and peers in children's social networks.

Adolescent↗

PubMed1994

Sexual practices and intentions among preadolescent and early adolescent low-income urban African-Americans.

OBJECTIVE: To assess the sexual practices and the social and intrapersonal influences on sexual practices and intentions which have an impact on the risk for acquired immunodeficiency syndrome among pre- and early adolescent, low-income African-American youths. DESIGN: Cross-sectional cohort study conducted in nine recreation centers serving three public housing developments in an eastern city. PARTICIPANTS: Three hundred fifty-one African-American youths 9 to 15 years of age. OUTCOME MEASURES: Past and intended sexual intercourse, and past and intended condom use determined by a risk assessment instrument delivered aurally and visually via a "talking" MacIntosh computer. RESULTS: The median age was 11 years; 35% of youths had had sexual intercourse and 20% of virgins thought it likely that they would become sexually active in the next six months. Age and male gender were correlated with sexual activity. Of sexually active youths 62% had used a condom during their last episode of coitus and 60% expected to do so at the next episode. Among sexually active youths, 24% of boys and 35% of girls had had anal intercourse. Rates of foreplay (nonpenetrative sex) were low even among sexually active youths. The median number of sexual partners in the past six months was two. Social influences from parents, peers, and partners in an intimate relationship were important for all four sexual outcomes both by univariate analysis and after logistic regression. IMPLICATIONS: A high percentage of the low-income, urban African-American pre- and early adolescents in this study are engaging or intending to engage in high-risk sexual behaviors. Acquired immunodeficiency syndrome reduction interventions for early adolescents should incorporate the importance of social influences from multiple sources.

Acquired Immunodeficiency Syndrome↗

PubMed1994

Drug trafficking among African-American early adolescents: prevalence, consequences, and associated behaviors and beliefs.

OBJECTIVE/METHODOLOGY: Drug trafficking by minority youths in low-income, urban areas has received considerable publicity from the mass media in the past half-decade. However, there has been corresponding little exposition of this problem in the medical literature. This review was undertaken to provide an overview of the epidemiology and consequences of drug trafficking among urban youths and to describe factors associated with drug trafficking. RESULTS: Existing data indicate that approximately 10% of male, urban, African-American early adolescents report having engaged in drug trafficking, with a higher percent of youths reporting having been asked to sell drugs and/or indicating that they expect to become involved in drug trafficking. Rates increase with advancing age. Reported rates of drug trafficking are comparable with rates of tobacco and alcohol use among early adolescents and are substantially higher than use rates of illegal drugs. Drug trafficking is associated with increased mortality, accounting for one third to one half of homicide-related deaths in some studies. The practice is also associated with other health-risk behaviors, including nonfatal violence, substance use, and incarceration. Perceived social pressures by family members and/or peers to engage in drug trafficking and the belief that a youth's wage-earning potential is limited to drug trafficking are highly correlated with involvement in this activity. CONCLUSIONS: Drug trafficking is a prevalent risk behavior among adolescents that has several negative health consequences.

Adolescent↗

PubMed1993

Salivary protein interactions with oral bacteria: an electrophoretic study.

The relatively low levels of human salivary proteins in whole saliva as compared to the ductal secretions may be related to their interaction with oral bacteria. These interactions are thought to play an important role in the microbial colonisation of the mouth, and salivary proteins adsorbed to oral surfaces have been implicated in adherence. In this study we attempted to investigate the prevalence of interactive strains by screening a range of oral bacteria. Parotid saliva was incubated with bacterial suspensions and consequent alterations to the salivary protein profile determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). A number of salivary components were found to be preferentially removed, particularly by those species known to be primary colonizers of clean tooth surfaces.

Animals↗

PubMed1993

Perceptions of vaccine efficacy, illness, and health among inner-city parents.

A resurgence of measles in the past decade has focused attention on the limitations of current immunization programs, particularly for inner-city, low-income populations. As part of a larger study of immunization rates, we discussed perceptions of disease severity and vaccine efficacy, as well as the prioritization of the tasks of parenthood, with 40 parents of infants living in inner-city Baltimore to discover their beliefs about immunization. Vaccines were considered only partly successful; susceptibility to chickenpox after vaccination was repeatedly cited as evidence of vaccine failure. Fever was seen as a primary indicator of illness; thus, vaccines were believed to cause, rather than prevent, illness. Immunization was not considered a high-priority parental responsibility. These findings suggest future interventions be aimed at changing parental perceptions of vaccines as ineffective and of fever after immunization as an indicator of illness. Finally, immunizations should be made easily available, even during clinic visits for a child's illness.

Baltimore↗

PubMed1993

Urban adolescent high-risk sexual behavior: corroboration of focus group discussions through pile-sorting. The AIDS Youth Research Team.

Risk activities for acquisition of the human immunodeficiency virus (HIV) remain prevalent among urban adolescents. While interdisciplinary approaches to examine the variables contributing to risk/protective behaviors have been promoted, strategies for such explorations require further formulation. Recently we employed focus group discussions to explore factors placing urban adolescents at risk for engaging in HIV risk behaviors. The focus group format enables substantial interaction on a topic in a limited time period, but does not always provide expression of the full range of behavioral options. In this study we investigated the use of pile-sorts for confirmation of impressions from focus group discussions among 57 urban youths aged 10-14. The pile-sorts revealed some support for most of the views expressed in the group discussions. However, the sorts revealed more variability in views than was expressed in the group discussions. Substantial gender and age-based differences in perceptions were revealed with potentially important intervention implications.

Adolescent↗