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Biomedical subjects

J A Neff

Publications and source records attributed to J A Neff.

At least 19 recordsLinked to original sources
PubMed2003

Reaching impaired populations with HIV prevention programs: a clinical trial for homeless mentally ill African-American men.

This study tested an intervention to reduce sexual risk behaviors in a high risk impaired population: homeless African-American, Caucasian and Hispanic men with mental illness. In a comparison group clinical trial, men were assigned to an experimental cognitive-behavioral or a control intervention and followed up over 16 months. Men were recruited from a psychiatric program in two shelters for homeless men in Nashville, Tennessee. An ethnically mixed cohort of subjects (54% African-American, 42% Caucasian and 4% Hispanic) were included in the study. Most had a chronic psychiatric disorder and a co-morbid substance abuse disorder. The 257 participants who were sexually active (130 experimental, 127 control) prior to the trial were the main target of the intervention. An experimental intervention (SexG), adapted from Susser and Associates (51), comprised 6 group sessions. The control intervention was a 6-session HIV educational program. Sexual risk behavior was the primary outcome. The experimental and control groups were compared with respect to the mean score on a sexual risk index. Complete follow-up data were obtained on 257 men (100%) for the initial six-month follow-up. These individuals have been followed for the remainder of the 16-month follow-up. This intervention, (SexG), successfully reduced sexual risk behaviors of homeless mentally ill African-American, Caucasian and Hispanic men. Similar approaches may be effective in other impaired high-risk populations.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Differential N-demethylation of l-alpha-acetylmethadol (LAAM) and norLAAM by cytochrome P450s 2B6, 2C18, and 3A4.

Incubation of l-alpha-acetylmethadol (LAAM) or norLAAM with cDNA-expressed P450s 3A4, 2B6, and 2C18 produced significant N-demethylation products. P450s 2C19, 2C8, 3A5, 2C9, 3A7, 1A1, and 2D6 (norLAAM only), also produced detectable product. Coexpression of cytochrome b(5) enhanced LAAM N-demethylation, most dramatically for 3A4, but had marginal effects on norLAAM N-demethylation. Modeling total liver metabolism using immunoquantification and relative activity factors of P450s suggests contributions of P450 3A4 > 2B6 > 2C18, with the importance of 2B6 to 2C isozymes enhanced by relative activity factors. The ratio of dinorLAAM to norLAAM plus dinorLAAM formed from LAAM did not exceed 20%, and was isozyme and cytochrome b(5) coexpression dependent. This ratio decreased with concentration with 3A4, but was relatively constant for 2B6 and 2C18. The human liver microsomes substrate-concentration response was similar to cDNA-expressed 3A4, but the ratio was higher. Changes in the environment of cDNA-expressed 3A4 also effected the magnitude of the ratio, but not the concentration-dependent decrease. These studies show that the N-demethylation of LAAM and norLAAM is not restricted to P450 3A4, particularly P450s 2B6 and 2C18, and suggest that the mechanism of sequential metabolism for 3A4 differs from that of 2B6 and 2C18.

Animals↗
PubMed2000

Intensive outpatient treatment of persons with mental retardation and psychiatric disorder: a preliminary study.

The impact of intensive outpatient mental health interventions (in a dual diagnosis clinic) on the hospitalization rate and length of stay was examined for 28 adults with mental retardation and severe psychiatric disorder. They were selected on the basis of frequent use of mental, medical, and social services. Charts were reviewed for the 12-month periods before and after referral to the program to compare service utilization. A single group pretest-posttest design with no control group was employed. Correlated t tests comparing the pre- and post-program number of hospitalizations and lengths of stay indicated significant decreases in both hospitalizations and lengths of stay after program entry, which may result in significant reductions in hospital costs.

Adolescent↗
PubMed2000

Predicting treatment-seeking behavior: psychometric properties of a brief self-report scale.

Development of a brief instrument to assess attitudes toward treatment and predict treatment-seeking behavior among out-of-treatment substance misusers is described. Exploratory factor analysis of an initial pool of 41 items identified four subscales: Perceived need for treatment: perceived drug problem severity; motivation to quit; and negative attitudes toward treatment. Psychometric analyses of data from 535 substance misusers participating in an outreach intervention project provided substantial support for the reliability and construct validity of the first three subscales, and marginal support for the fourth. Evidence of predictive validity was provided by further analyses indicating significant relationships between the three primary scales and both treatment admissions and treatment-seeking during a 3-month follow-up period. The final instrument, the Treatment Attitude Profile (TAP), contains 25 items in a self-report format suitable for use with limited literacy populations in field or office settings.

Attitude to Health↗
PubMed1999

Surface modification for controlled studies of cell-ligand interactions.

This work describes a method for coupling cell adhesion peptides to hydrophobic materials for the purpose of controlling surface peptide density while simultaneously preventing nonspecific protein adsorption. PEO/PPO/PEO triblock copolymers (Pluronic F108) were equipped with terminal pyridyl disulfide functionalities and used to tether RGD containing peptides to polystyrene (PS). The density of F108 on PS was 1.4 E5 +/- 2.12 E1 molecules/microm2. XPS and ToF SIMS indicated that the F108 coating was homogeneous and that the unmodified and activated F108 distributed evenly on PS. By mixing unmodified F108 with PDS-activated F108 prior to adsorption, it was possible to vary peptide density between 0 and 8.7 E4 +/- 2.66 E3 peptides/microm2, while otherwise, maintaining consistent surface properties. GRGDSY grafted PS supported cell attachment, spreading, and development of cytoskeletal structure, all of which were found to increase with increasing peptide density. Cell proliferation followed this same trend, however, maximal growth occurred at a submaximal peptide density. Cell aspect ratio varied in a biphasic manner with GRGDSY density. F108 coated PS and GRGESY grafted PS were inert to cell adhesion. Cells released from GRGDSY grafted PS upon addition of either a reducing agent or free GRGDSY, which indicates that cell-substrate interactions were mediated solely by the tethered peptides.

3T3 Cells↗
PubMed1999

HIV/AIDS mental health training for health care providers: an evaluation of three models.

Three models of continuing education--full-day, half-day, and brief workshop--for health providers treating patients with HIV/AIDS were compared on measures of effectiveness with regard to knowledge, attitude, and practice outcomes. Analyses of pre- and postintervention data from two years of training events suggest consistent, modest, program effects in the full-day and half-day approaches, specifically in the area of knowledge enhancement.

Acquired Immunodeficiency Syndrome↗
PubMed1998

A novel method for surface modification to promote cell attachment to hydrophobic substrates.

The ability to study and regulate cell behavior at a biomaterial interface requires strict control over material surface chemistry. Perhaps the greatest challenge to researchers working in this area is preventing the fouling of a given surface due to uncontrolled protein adsorption. This work describes a method for coupling peptides to hydrophobic materials for the purpose of simultaneously preventing nonspecific protein adsorption and controlling cell adhesion. A hexapeptide containing the ubiquitous RGD cell-adhesion motif was coupled to polystyrene (PS) via a polyethylene oxide (PEO) tether in the form of a modified PEO/PPO/PEO triblock copolymer. Triblocks were adsorbed onto PS at a density of 3.3 +/- (5.14 x 10(-4)) mg/m2 (1.4 x 10(5) +/- 2.12 x 10(1) molecules/microm2), which was determined by isotope 125I labeling. The peptide, GRGDSY, was activated at the N terminus with N-Succinimidyl 3-(2-pyridyldithio) propionate and coupled to immobilized triblocks where the terminal hydroxyls had been converted to sulfhydryl groups. Surface peptide density was measured by amino acid analysis and found to be 1.4 x 10(4) +/- 0.47 x 10(4) molecules/microm2. PS modified with PEO/PPO/PEO copolymers alone was found to be inert to cell adhesion both in the presence of serum proteins and when exposed to activated RGD peptide. In contrast, PS conjugated with RGD via endgroup-activated PEO/PPO/PEO copolymers supported cell adhesion and spreading. The surface coupling scheme reported here should prove valuable for studying cell-ligand interactions under simplified and highly controlled conditions.

3T3 Cells↗
PubMed1998

The Health Belief Model and HIV risk behaviours: a causal model analysis among Anglos, African-Americans and Mexican-Americans.

A causal model of the Health Belief Model (HBM) is empirically evaluated which emphasizes possible indirect paths linking distal demographic and seriousness/susceptibility variables to HIV risk behaviours among Anglo, African-American, and Mexican-American adults. A specific focus of the paper is upon alcohol-related expectancies (anticipation of disinhibitory effects of alcohol upon sexual behavior) as a 'barrier' to preventive behaviours. Ethnic comparisons stem both from the paucity of available research on the HBM in minority populations and from recent questions regarding the applicability of rational models such as the HBM among minority groups. Analyses of data from a community sample of 1390 adults indicate relatively consistent direct effects of barriers for males and benefits for females upon HIV risk behaviors. The analyses suggest distinct paths operative among males and females. The susceptibility-barriers-risk behaviours path among males may suggest that alcohol-related expectancies (barriers in this model) may be more strongly related to risk behaviours among males than minority females.

Adult↗
PubMed1998

Continuing medical education versus clinic-based STD and HIV education interventions for primary care service providers: replication and extension.

An evaluation of a 2-day sexually transmitted disease (STD) and HIV and AIDS curriculum for primary care providers is presented which compares large scale continuing medical education (CME) conferences with smaller clinic workshop (CW) models with regard to short-term (2-month) and long-term (10-month) program effects on STD and HIV knowledge, attitudes toward risk assessment, and frequency of both STD diagnosis and STD and HIV risk counseling. Data from interventions held in San Antonio, Texas (328 CME; 95 CW) replicate and extend earlier findings from a preliminary intervention, indicating nonsignificant CME-CW differences and dramatic and long-lasting gains from baseline among those with lower knowledge and experience levels preintervention. Similar program effect magnitudes were found for attitude and practice dimensions at 2 months postintervention, with the strongest consistent short and long-term program effects observed for STD and HIV knowledge among service providers.

Adult↗
PubMed1995

Alcohol use, liberal/conservative orientations, and ethnicity as predictors of sexual behaviors.

The present study examined relationships among ethnicity, gender, alcohol consumption, and sexual behaviors in a community survey sample of 1,392 adults. Predictors included liberal versus conservative orientations (sex role orientation, religiosity); traditional versus liberal attitudes regarding sexuality, typical alcohol consumption patterns, expectancies regarding alcohol's effect upon one's sexuality, and frequency of alcohol use before sex. Findings are consistent with other studies indicating more sex partners among males than females and among Blacks (particularly males) than Anglos. Blacks also reported less involvement in oral sex than Anglos and Mexican-Americans--although observed differences for oral sex were more characteristic of females and less characteristic of unmarried nondrinkers. Unmarried Mexican-American males reported somewhat, though not significantly, more partners than did Anglos. Unmarried Black males (particularly nondrinkers) also reported more frequent risky behaviors than did Anglos. Divorced Black female drinkers reported significantly less frequent risky behavior than their Anglo counterparts. Alcohol use-sexual relationships were independent of psychosocial background characteristics and situated drinking (drinking before sex) was more strongly related to sexual behavior dimensions than were general drinking patterns.

Acculturation↗
PubMed1992

Acculturation and drinking patterns among U.S. Anglos, blacks, and Mexican Americans.

The relationship between acculturation, generational status/nativity and drinking patterns is examined using data from a 1988 community survey of 1286 adult regular drinkers (at least two drinks/month) in San Antonio, Texas. This sample includes 412 Anglo, 239 Black, and 635 Mexican American respondents, with Mexican Americans further classified into high, medium, and low acculturation groups using a language-use-based acculturation measure. This data set allows comparisons between racial/ethnic majority and minority groups with further comparisons between Black and Mexican American subgroups. These racial/ethnic and acculturation level comparisons highlight the effects of minority status and cultural differences between groups with regard to drinking patterns. Overall, the analyses indicate little evidence to support an 'acculturation stress' model of alcohol use, wherein the stresses of acculturation produce higher levels of alcohol consumption among moderately or higher acculturation groups. Generally, in our data, quantity and frequency consumption was somewhat higher among the least acculturated males and moderately acculturated females. Further analyses by generational status indicate heavier consumption patterns among second-generation individuals, especially among the less acculturated, though those differences were eliminated by controls. The findings highlight inadequacies of using generational status/nativity measures alone to assess acculturation level. Further, joint effects of acculturation level and generational status suggest the viability of a cultural marginality model of acculturation, though many of the effects of acculturation and generational status are explained by demographic and psychosocial factors.

Adult↗
PubMed1991

"Machismo," self-esteem, education and high maximum drinking among anglo, black and Mexican-American male drinkers.

This study seeks to clarify the relevance of machismo to patterns of high maximum drinking among male drinkers. Specifically, the study describes the psychometric properties of a newly developed 7-item machismo measure, compares levels of machismo and self-esteem for a sample of Anglo, black and Mexican-American males, and examines both main and interaction effects of machismo, self-esteem and education as predictors of alcohol use in these racial/ethnic subgroups. Logistic regression analyses document interaction between race/ethnicity, machismo, self-esteem and education, which calls into question the presumed importance of machismo as a cultural element causing heavy drinking patterns among Mexican-American males.

Adult↗
PubMed1990

Explaining trends in use of VA inpatient psychiatric services.

We examined the expansion of Veterans Administration (now Department of Veterans Affairs--VA) inpatient psychiatric services from 1963 to 1984. Aggregate national trends in VA inpatient episodes between 1963 and 1984 document not only increased use of inpatient services but also "decentralization," or a shift to providing psychiatric services in general VA medical centers. The national trends show a dramatic increase in admissions to psychiatric bed sections over the period 1963-1978, with admissions staying at this high level from 1976-1981 and dropping only slightly in the 1980s. Admission trends were disaggregated into first admissions and readmissions to psychiatric and general hospitals in a single VA medical district for the period 1972-1981. First admissions declined over the study period for both hospital types; readmissions increased initially, but declined somewhat at the end of the period. The admission trends and patterns in source of first admissions suggest that the growth of VA services reflects psychiatric "decentralization," as well as deinstitutionalization within VA.

Deinstitutionalization↗