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Biomedical subjects

W Hall

Publications and source records attributed to W Hall.

At least 19 recordsLinked to original sources
PubMed1992

Murine B7 antigen provides a sufficient costimulatory signal for antigen-specific and MHC-restricted T cell activation.

We have previously shown that the murine B7 (mB7) molecule, when expressed in Chinese hamster ovary cells in stable fashion, can costimulate with anti-CD3 mAb or Con A to induce T cell activation. We have now derived, by gene transfection, Chinese hamster ovary cell lines that express the I-Ad molecule, either alone or in context with mB7. We have analyzed these transfectants for their capacity to present Ag to murine CD4+ T lymphocytes. I-Ad/mB7-double transfectants were able to stimulate mixed lymphocyte reactions and to present peptide Ag to specific T cells. Chinese hamster ovary cells that expressed only the I-Ad molecule were not able to stimulate T cell proliferation in these systems. Thus, the mB7 protein is a sufficient costimulatory molecule for the physiologic, Ag-dependent/MHC-restricted activation of murine CD4+ T cells. Stimulation of T cell bulk cultures resulted predominantly in the production of IL-2 and not of IL-4. The costimulatory activity of mB7 is not, however, restricted to the IL-2-secreting subset. We have identified one IL-4-secreting T cell clone, CDC35, which is responsive to mB7 triggering. Finally, we present experiments that suggest that mB7 and peptide/MHC complexes need to be expressed on the same cell for optimal induction of T cell activation.

Animals↗
PubMed1992

Relationship of anxiety and depression.

There has been considerable controversy regarding the relationship between depression and anxiety. We review briefly the descriptive, longitudinal, genetic, biological, and treatment response data indicating that there is overlap between depression and anxiety. Several possible models are explored that provide different conceptions of how this relationship may best be understood: (1) that there are a variety of more or less discrete, but sometimes coexisting, syndromes within the spectrum of anxiety and depression; (2) that symptoms of depression and anxiety represent different external manifestations of a more basic underlying cause; (3) that one condition may predispose to the other; (4) that the association may be due to artifactual definitional overlap, particularly since the instruments used to measure depression and anxiety share so many items. All these propositions are supported. An important, practical question is discussed--should the mixed anxiety/depressive disorder that has been suggested by ICD-10 be included in DSM-IV?

Anxiety↗
PubMed1992

Benzodiazepine use and HIV risk-taking behaviour among injecting drug users.

This paper examines the prevalence of benzodiazepine use, and its relationship to other drug use and HIV risk-taking among a sample of 1245 injecting drug users (IDU). Approximately a third (36.6%) of the sample had used benzodiazepines during their last typical month of injecting. Benzodiazepine users had injected more frequently, injected more heroin and amphetamines, and had more poly-drug use than other IDU. They also had higher levels of HIV risk-taking, having shared injecting equipment more frequently and with more people. There were no differences between groups in number of sexual partners or condom use, although benzodiazepine users were more likely to have been paid for sex. The demographic and drug use variables indicate that benzodiazepine users are a more dysfunctional subgroup of IDU who require particular attention in HIV interventions.

Adult↗
PubMed1992

Liver carcinogenesis by methyl carbamate in F344 rats and not in B6C3F1 mice.

Short-term and long-term carcinogenicity of methyl carbamate (MCB) was evaluated in F344 rats and B6C3F1 mice. In experiments lasting 6, 12, and 18 months, MCB was given in water by gavage to groups of 10 male and 10 female rats at 0 or 400 mg/kg body weight, 5 days per week, and to similar groups of mice at 0 or 1,000 mg/kg. At 6 months, MCB induced atypical mitoses, cytologic alterations, cytomegaly, pigmentation, necrosis, and neoplastic nodules of the liver in rats. At 12 and 18 months, carcinomas of the liver were induced by MCB in 80-90% of male rats and in 60-80% of female rats. None was observed in control rats or in mice. In the 2-year studies, MCB was given to groups of 50 male and 50 female rats at 0, 100, or 200 mg/kg and to similar groups of mice at 0, 500, or 1,000 mg/kg, 5 days/week. Chronic focal inflammation, cytologic alteration, hyperplasia, and neoplastic nodules and carcinomas (200 mg/kg groups only) of the liver were induced by MCB in rats. Liver tumor incidence data for combined experiments in rats were: males--5% in controls, 0% in 100 mg/kg group, 14% in 200 mg/kg group, and 77% in 400 mg/kg group; females--5% in controls, 0% in controls, 0% in 100 mg/kg group, 12% in 200 mg/kg group, and 63% in 400 mg/kg group. MCB was not shown to be carcinogenic in mice.

Animals↗
PubMed1992

Methadone maintenance and the human immunodeficiency virus: current issues in treatment and research.

This paper examines the changes that have occurred in methadone maintenance programmes in response to the advent of HIV and the adoption of harm minimization policies, and the implications of these changes for research. A need for the use of more rigorous research methods is identified and recommendations are made that take into account both the ethical and practical difficulties of conducting research in this area. Both old, unanswered questions that have resurfaced with the recent massive growth in methadone programmes in some countries, and new questions that need to be answered in order to improve the effectiveness of methadone maintenance in the fight against HIV infection are identified as future areas in need of research.

HIV Infections↗
PubMed1992

A comparison of predictors of treatment drop-out of women seeking drug and alcohol treatment in a specialist women's and two traditional mixed-sex treatment services.

The problem of high levels of client drop-out in drug and alcohol treatment is frequently reported in the literature. In the course of conducting an evaluation of a specialist women's treatment service, the inadequacy of the data on women-specific predictors of treatment drop-out was highlighted. Using a retrospective design, the characteristics of 160 women who left treatment less than 5 days after admission were compared to the 160 women who stayed longer than 5 days and were enrolled in the evaluation study. The findings of this study suggested that women who were employed, had a history of sexual assault (especially in adulthood), nominated alcohol as their drug of choice, were not married, older than 25 years of age and had demonstrated a sympathy with the agency's treatment philosophy were less likely to drop-out of treatment. In addition, for lesbian women, women with a history of sexual assault in childhood, and those with dependent children, attendance at a specialist women's service reduced the incidence of treatment drop-out.

Adolescent↗
PubMed1992

Recreational MDMA use in Sydney: a profile of 'Ecstacy' users and their experiences with the drug.

'Ecstasy' (3,4-methylenedioxymethamphetamine or MDMA) is a recreational drug that is gaining popularity world wide. There is a paucity of research regarding the ways in which Ecstasy is used and the nature of its effects. A 'snowball' peer network technique was used to recruit 100 users who completed anonymous questionnaires. The research revealed that Ecstasy is primarily used by infrequent recreational drug users for 'fun' at dance parties and social gatherings. The primary reported effects of Ecstasy were a 'positive mood state' and feelings of intimacy and closeness to others. The secondary effects of Ecstasy were the stimulant effects of energy and activation, and the psychedelic effects of insight and perceptual and sensual enhancement. Ecstasy was reported to share the properties of both amphetamines and hallucinogens in the nature of its side effects and residual effects which were no more severe than those of the latter two classes of drug. It appeared Ecstasy was not conductive to regular and frequent use, because tolerance was reported to develop to the positive effects of Ecstasy, while negative effects increased with use. Although few problems associated with the recreational use of Ecstasy have surfaced to date, animal research has shown it to be neurotoxic to serotonergic nerve terminals. Caution must be observed until further research can determine the level of hazard in humans.

3,4-Methylenedioxyamphetamine↗
PubMed1992

Changes in criminal activity after entering methadone maintenance.

The impact of different approaches to methadone maintenance on the level of crime committed by heroin addicts was examined in a cohort of addicts entering methadone treatment. The cohort comprises three groups: 72 subjects (group 1) who were approved for treatment and referred to a long-term programme which tolerated continued illicit drug use in treatment; 159 subjects (group 2) who were referred to an abstinence orientated programme from which clients who continued to use heroin were expelled; and 84 subjects who were rejected as unsuitable or failed to complete the assessment process. Official records of convictions were used to calculate conviction rates in the pre- and post-assessment periods. Differences between groups in conviction rates for drug and property crimes were analysed using Poisson regression. Three variables--age, sex and age of first criminal conviction--were significant predictors of conviction rates and all analyses controlled for these variables. Most of the rejected subjects entered treatment during the study period and it was, therefore, not possible to interpret differences between treated and untreated subjects. Among those who entered treatment, property offence rates actually rose, due to a significant increase in conviction rates in group 2. Subjects in group 1 were retained significantly longer in treatment than those in group 2. Among those who remained in treatment less than 12 months, most offences occurred after leaving treatment. When conviction rates were adjusted for time spent in treatment, the differences between the clinics disappeared.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Development and validation of a multi-dimensional instrument for assessing outcome of treatment among opiate users: the Opiate Treatment Index.

This article presents a new instrument with which to assess the effects of opiate treatment. The Opiate Treatment Index (OTI) is multi-dimensional in structure, with scales measuring six independently measured outcome domains: drug use; HIV risk-taking behaviour; social functioning; criminality; health; and psychological adjustment. Psychometric properties of the Index are excellent, suggesting that the OTI is a relatively quick, efficient means of obtaining reliable and valid data on opiate users undergoing treatment over a range of relevant outcome domains.

Adolescent↗
PubMed1992

Development of a short 'readiness to change' questionnaire for use in brief, opportunistic interventions among excessive drinkers.

Excessive drinkers (141) identified in medical settings who were not seeking help for an alcohol problem completed a questionnaire based on Prochaska and DiClemente's stages of change model. Principal components analysis revealed a clear factor structure corresponding to the 'precontemplation', 'contemplation' and 'action' stages of change. On this basis, a 12-item 'Readiness to change' questionnaire was developed with satisfactory psychometric properties. As predicted, scale scores on adjacent stages of change showed significantly higher inter-correlations than scores on non-adjacent stages. Concurrent validation by comparison with subjects' choices of cartoons depicting each of the stages of change and with screening questions regarding aspects of drinking behaviour was moderate to very good. The questionnaire provides a short and convenient measure of readiness to change which may be used in conjunction with brief, opportunistic interventions with excessive drinkers.

Adult↗
PubMed1992

A comparison of women seeking drug and alcohol treatment in a specialist women's and two traditional mixed-sex treatment services.

The paucity of research on the treatment needs of women with substance abuse problems has been a serious impediment to the development of empirically validated treatment programmes. Women continue to be seriously under-represented as research subjects and clients of treatment services. This study compares the characteristics of 80 women attending a specialist women's treatment service with those of eighty women attending two traditional mixed-sex treatment agencies. Women attending a gender-sensitive service were significantly more likely to have dependent children, to be lesbian, to have a maternal history for drug or alcohol problems and to have suffered sexual abuse in childhood. These results suggest that gender-sensitive treatment services may be recruiting women who might not otherwise have sought treatment for their substance dependence problems.

Adolescent↗
PubMed1992

The public perception of the risks and benefits of alcohol consumption.

A survey of the community was undertaken in August 1989 to assess the public's perception of the risks and benefits of alcohol use, and their understanding of recommended levels of safe alcohol consumption. A household sample of 500 men and women (18 to 65 years) in metropolitan and rural New South Wales were asked their opinions about the risks and benefits of alcohol use, the health and social consequences of 'drinking too much', and the number of standard drinks that would produce a low, medium and high risk to the health of an adult man and woman. The major perceived benefits of alcohol use were relaxation and medication; the major health and social problems attributed to alcohol abuse were brain and liver damage, and domestic violence and family problems. The quantities of alcohol which respondents thought could be consumed with a 'low' risk to health were close to National Health and Medical Research Council recommended levels of safe consumption.

Adult↗
PubMed1992

Estimates of the number of injecting drug users in a defined area.

Three estimates of the number of injecting drug users residing within the Eastern Sydney Area Health Service (ESAHS) were obtained by applying the capture-recapture technique to data from three reliable sources, specifically, Methadone Services, the Bourke Street Drug Advisory Service and the Albion Street Clinic. The obtained estimates were 3449, 3046 and 1103 respectively. Statewide methadone statistics were also used to obtain an estimate of 15,082 injecting drug users in New South Wales. This estimate was close to the linearly projected estimates (14,274 and 14,416) from two previous studies. Estimates based upon the methadone statistics indicate that approximately 23% of injecting drug users in New South Wales reside within the ESAHS. A sensitivity analysis was performed to assess the effects on the estimates of the likely violation of the closed population assumption.

Ambulatory Care↗
PubMed1992

Anxiety, depression and HIV related symptomatology across the spectrum of HIV disease.

Levels of anxiety and depression were assessed for 207 HIV seropositive homosexual/bisexual men (AIDS = 34, ARC = 72, asymptomatic HIV infection = 101), and 36 seronegative controls. Lymphocyte subset enumeration, history of opportunistic infections, and occurrence of HIV-related symptoms were recorded at the time of assessment. No differences between groups were found on age, educational level, state/trait anxiety or depression scores. Neither the number of symptoms reported, their duration, severity, frequency of occurrence, nor the proportion of patients who reported a specific symptom was different between the three HIV seropositive groups. Severity of anxiety and depression was related to the magnitude of symptomatology, but not associated with either degree of immunodeficiency, number of opportunistic infections or diagnostic group. Principal component analysis extracted five symptom factors (cognitive, affective, psychosocial, neurological and physical), none of which predicted state anxiety scores. However, affective and psychosocial symptom factors predicted trait anxiety and depression scores. The results indicate that ratings of anxiety and depression are independent of stage of HIV infection, may be in part mediated by constitutional and physical symptoms of HIV disease, but are primarily associated with the presence of psychological and psychosocial symptoms.

AIDS Dementia Complex↗
PubMed1992

Hypermedia in biomedical education: a case study.

The origination, development and application of a hypermedia system for use in the life sciences is described. Implemented in the Apple Macintosh HyperCard environment, the project has been designed to make use of commercially produced laser discs as visual archives and has included the production of authoring and navigational tools. We report here on our experience in authoring stacks for undergraduate teaching, monitoring of student use and assessment of effectiveness as a self-teaching resource. Future developments and applications within the biomedical sciences are discussed.

Biological Science Disciplines↗
PubMed1991

Effect of amphetamine on cerebral blood flow and capillary perfusion.

The purpose of this study was to determine the cerebral regional microvascular and vascular responses to amphetamine sulfate at a dose (5 mg/kg) known to affect neuronal function. Cerebral blood flow (14C-iodoantipyrine method) and percent of perfused capillaries (fluorescein isothiocyanate-dextran and alkaline phosphatase staining method) were determined during control and after intravenous administration of amphetamine in conscious Long-Evans rats. Amphetamine caused an increase in blood pressure (34%) and heart rate (31%). There was a significant increase in averaged cerebral blood flow from 98 +/- 8 to 166 +/- 9 ml/min/100 g after amphetamine. This flow increase was significant in the cortex, basal ganglia, pons and medulla, however the increase was not significant in the hypothalamus. In control rats, there were approximately 325 +/- 17 capillaries/mm2 of brain tissue and 52 +/- 1% of them were perfused. Amphetamine increased the percent perfused significantly to 72 +/- 1% in all examined regions. There was a similar significant increase in the percent of perfused cerebral capillary volume fraction. There were both vascular and microvascular responses to amphetamine, increasing cerebral blood flow as well as reducing the diffusion distance for oxygen.

Amphetamine↗