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Biomedical subjects

B T Johnson

Publications and source records attributed to B T Johnson.

16 recordsLinked to original sources
PubMed1997

Enhancing motivation to reduce the risk of HIV infection for economically disadvantaged urban women.

This research evaluated a motivation-based HIV risk reduction intervention for economically disadvantaged urban women. Participants completed a survey that assessed HIV-related knowledge, risk perceptions, behavioral intentions, sexual communication, substance use, and risk behavior. A total of 102 at-risk women (76% African American) were randomly assigned to either the risk reduction intervention or to a waiting list. Women were reassessed at 3 and 12 weeks. Results indicated that treated women increased their knowledge and risk awareness, strengthened their intentions to adopt safer sexual practices, communicated their intentions with partners, reduced substance use proximal to sexual activities, and engaged in fewer acts of unprotected vaginal intercourse. These effects were observed immediately, and most were maintained at follow-up.

Adolescent↗
PubMed1997

The self-reference effect in memory: a meta-analysis.

In this review, the authors examine the basis for the mnemonic superiority that results from relating material to the self. A meta-analysis confirms the expected self-reference effect (SRE) in memory, with self-referent encoding strategies yielding superior memory relative to both semantic and other-referent encoding strategies. Consistent with theory and research that suggest self-reference (SR) produces both organized and elaborate processing, the SRE was smaller (a) when SR is compared with other-reference (OR) rather than semantic encoding and (b) when the comparison tasks promote both organization and elaboration. Thus, the SRE appears to result primarily because the self is a well-developed and often-used construct that promotes elaboration and organization of encoded information. The authors discuss the implications of these and other findings for theories of the SRE and for future research.

Adult↗
PubMed1996

Effectiveness of yohimbine in the treatment of erectile disorder: four meta-analytic integrations.

The results of four independent yet convergent meta-analyses to examine the efficacy of yohimbine in the treatment of erectile disorder are reported. These meta-analyses integrated data from (i) controlled clinical trials of yohimbine (when used alone), (ii) uncontrolled trials examining yohimbine (alone), (iii) controlled trials of yohimbine when used in combination with other drugs, and (iv) uncontrolled trials of yohimbine plus other drugs. Results document a consistent tendency for yohimbine, and for other medications containing yohimbine, to enhance erectile functioning relative to placebo. We also identify methodological and reporting difficulties that characterize much of the literature.

Alkaloids↗
PubMed1996

Interpersonal contact and acceptance of persons with psychiatric disorders: a research synthesis.

This meta-analytic review predicted and confirmed that interpersonal contact between mental health employees or students and persons diagnosed with psychiatric disorders is associated with improved attitudes toward the latter group. As also predicted, the amount of attitude change was found to be smaller, although still significant, when the evaluative measure described a group of the "mentally ill" rather than specific individuals, and when the respondents were mental health employees rather than students. Contrary to predictions, contact interventions of longer duration were not associated with greater attitude changes. It is concluded that contact interventions occurring in mental health settings are effective in promoting attitude changes toward persons with psychiatric disorders, and methodological refinements that should strengthen the effectiveness of future contact interventions are outlined.

Humans↗
PubMed1996

Elevated blood pressure and personality: a meta-analytic review.

A meta-analysis of 295 relevant effect sizes obtained from 25,469 participants confirmed expectations that elevated blood pressure (BP) and essential hypertension (EH) would be associated with lower affect expression but with more negative affectivity and defensiveness. The strongest associations occurred for defensiveness and measures of anger and affect expression linked to an interpersonal context(s). However, a number of other factors also were found to moderate associations of BP with personality measures, including awareness of BP status, gender, occupation, and diastolic versus systolic BP assessment. Given these moderators, the authors conclude that a traditional view of personality causing EH is untenable and that, not incorporating multifactorial, synergistic approaches is likely to obscure associations of personality-behavior with EH.

Adult↗
PubMed1988

Attitudes toward older and younger adults: a meta-analysis.

Attitudes toward the elderly have been examined in a number of empirical studies, yet the question of whether the elderly are viewed more negatively than younger persons has not been resolved. A meta-analysis of the literature was conducted to examine this question; results demonstrated that attitudes toward the elderly are more negative than attitudes toward younger people. However, smaller differences between the evaluations of elderly and younger targets were found when (a) the study used measures of personality traits (compared with measures of competence), (b) there were a larger number of dependent measures included in the effect size, (c) specific information was provided about the target person (compared with when a general target such as old person was used), and (d) a between-subjects design (compared with a within-subjects design) was used. These results support Lutsky's (1981) conclusion that age, in and of itself, seems to be less important in determining attitudes toward the elderly than other types of information. The methodological limitations within the literature and a need to consider multiple components of attitudes toward older individuals are discussed.

Adult↗
PubMed1984

Impact of an oil field effluent on microbial activities in a Wyoming river.

The survival, functions, and physiological diversity of autochthonous sediment microbiota were examined in situ at five stations along the Little Popo Agie River, WY; one station above, one at, and three below a discharge point for oil wastewater from Union Oil Company's Dallas Field. Below the oil wastewater discharge point there were increases in electron-transport activity, carbon dioxide production, and microbial populations of heterotrophs, ammonifiers, hexadecane degraders, starch hydrolyzers, protein hydrolyzers, and sulfate reducers. At a station 1420 m below the discharge point, however, overall sediment microbial activities and all of the physiological groups of bacteria, except hexadecane-degrading microbiota, were at levels comparable with those at the control station above the discharge point. Similarly, mineralization of glucose, amino acids, hexanoic acid, and hexadecane was elevated at stations directly below the discharge point, but appeared to subside rapidly. Xenobiotic biodegradation potential of the sediments varied with the chemical and the sample location and was not directly related to oil residue levels in the sediment. Microorganisms thus appeared to maintain physiological diversity and increased in numbers and activity in a riverine environment that contained petroleum hydrocarbon concentrations known to be deleterious to freshwater fish and macrobenthic communities.

Alkanes↗
PubMed1981

Biological effects of kepone and mirex in freshwater invertebrates.

Acute and chronic toxicity studies of Kepone (chlordecone) and mirex were conducted with daphnids (Daphnia magna), amphipods (Gammarus pseudolimnaeus), and larvae of a midge (Chironomus plumosus). Acute toxicities of Kepone ranged from a 48-hr EC50 of 350 microgram/L for midges to a 96-hr LC50 of 180 microgram/L for amphipods, whereas the acute toxicities of mirex to all three taxa exceeded 1000 microgram/L. Maximum acceptable toxicant concentrations (MATC's) for Kepone and mirex were estimated by measuring reproduction of daphnids, growth of amphipods, emergence of midges, and survival of all organisms. MATC for Kepone was estimated to be between 9 and 18 microgram/L for daphnids, between 1 and 2 microgram/L for amphipods, and between 8.4 and 18 microgram/L for midges; MATC for mirex exceeded 34 microgram/L for daphnids and midges, but less than 2.4 microgram/L for amphipods. The concentration of Kepone and mirex accumulated by daphnids was 760 and 8025 times, respectively, the concentration in water. Estimated times for elimination of 50% of the residues by daphnids were 141 hr for Kepone and 12 hr for mirex.

Animals↗
PubMed1973

Biomagnification of p, p'-DDT and methoxychlor by bacteria.

Aerobacter aerogenes and Bacillus subtilis accumulated p, p'-DDT and methoxychlor directly from water. Uptake of both (14)C-labeled organochlorine insecticides was rapid; 80 to 90% of the 24-h residues were reached within 30 min. Total cellular residues varied linearly with concentrations of DDT and methoxychlor in water ranging from 0.5 to 5.0 mug/liter. The residue magnification factors from water were between 1,400- to 4,300-fold, but were independent of insecticide concentrations in water. When the insecticide-exposed microbial cells were washed with pesticide-free water, DDT residues were 45% in A. aerogenes and 30% in B. subtilis, whereas the methoxychlor level decreased nearly 75% in both organisms. Subsequent washing did not further reduce the insecticide residue. Autoclave-killed bacteria also rapidly adsorbed DDT and methoxychlor from water and, in some instances, residues were higher than in the living cells. Molecular polarity and lipid solubility appear to influence the retention of the organochlorine insecticides by bacterial cells.

Autoradiography↗
PubMed1967

Conversion of DDT to DDD by pathogenic and saprophytic bacteria associated with plants.

Of 27 microorganisms examined, 23 plant pathogenic and saprophytic bacterial species were found to convert p,p' DDT to p,p' DDD under anaerobic conditions. The range of conversion of DDT (10 micrograms per milliliter) during an incubation of 14 days was from a trace to over 5 micrograms per milliliter, with the majority of the bacteria showing the greatest activity during the final 7-day period. There is evidence that metabolites of DDT other than DDD are also produced.

Alcaligenes↗
PubMedDate not supplied

Enhancing early discharge with home follow-up: a pilot project.

Although early hospital discharge of mothers and infants reduces health care costs, it also decreases the opportunities for women to learn the mothering role with the help of health care providers. This article describes the development of a program in which hospital staff nurses provide follow-up care to new mothers and their infants in the home. In addition, it compares the nonroutine health care expenditures in the postpartum period of mother-infant dyads receiving this service and of dyads who did not.

Adolescent↗