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Biomedical subjects

John Davidson

Publications and source records attributed to John Davidson.

8 recordsLinked to original sources
PubMed2003

STAT1-dependent innate immunity to a Norwalk-like virus.

Norwalk-like caliciviruses (Noroviruses) cause over 90% of nonbacterial epidemic gastroenteritis worldwide, but the pathogenesis of norovirus infection is poorly understood because these viruses do not grow in cultured cells and there is no small animal model. Here, we report a previously unknown murine norovirus. Analysis of Murine Norovirus 1 infection revealed that signal transducer and activator of transcription 1-dependent innate immunity, but not T and B cell-dependent adaptive immunity, is essential for norovirus resistance. The identification of host molecules essential for murine norovirus resistance may provide targets for prevention or control of an important human disease.

Animals↗
PubMed2003

Balancing hospital and community treatment: effectiveness of an extended-hours community mental health team in a semi-rural region of australia.

OBJECTIVE: To examine the effectiveness of the introduction of a community mental health team on consumer psychosocial outcomes. DESIGN: Longitudinal panel design. SETTING: District general hospital in a semi-rural region of Australia. NUMBERS: Two matched groups (n = 37 in each group) MAIN OUTCOME MEASURE: These included: Brief Psychiatric Rating Scale (BPRS), Global Assessment Scale (GAS), Rosenberg Self-Esteem, Life Skills Profile as well as self-report. RESULTS: The study found that the introduction of the new service resulted in few significant differences in consumer outcomes. CONCLUSIONS: The paper argues that because the state was the only specialist mental health service provider and it was unable to offer assertive community treatment, hospital care remained central. Evidence that a substantial proportion of consumers and carers preferred hospital to community care is placed against this background. The paper argues that in regions like these, where community-based services are likely to remain underdeveloped, it may be best to maintain quality hospital services and to target community services more precisely on what is achievable rather than developing community services at the expense of hospital care. WHAT IS ALREADY KNOWN: Studies on the efficacy of assertive community treatment suggest that it can lead to improved consumer outcomes. However, these studies are usually in urban settings and involve experimental teams. In many rural and regional areas community treatment teams offer standard rather than assertive community care. It is therefore important to investigate the effectiveness of community treatment teams in rural and regional Australia. WHAT THIS STUDY ADDS: This study suggests that in rural and regional areas characterised by limited resources, it is too much to expect community treatment teams to have a measurable impact on consumer outcomes. In these settings hospital care remains at the heart of the service. This means that regions such as these need to focus their community services on what is achievable given the level of resources and social ecology. For example, they may need to consider offering either crisis intervention or rehabilitation services and to rely on innovations, such as telehealth or strategic alliances with other service providers to fill the gap.

Attitude to Health↗
PubMed2002

Metabolites released by Cryptococcus neoformans var. neoformans and var. gattii differentially affect human neutrophil function.

Differences in the ability of Cryptococcus neoformans var. neoformans (CNVN) and var. gattii (CNVG) to establish localized lesions in the lungs of healthy humans remain unexplained. In this study, CNVG infection in a rat model was characterized by early neutrophil invasion into lung tissue, but phagocytosis of cryptococci was not observed. The chemical composition of non-enzymic components secreted by one strain of each variety (heat-inactivated supernatants from CNVN and CNVG, termed vns and vgs, respectively) were compared, using magnetic resonance spectroscopy. Effects on human neutrophil viability and functions at both pH 5.5 and 7.0 were investigated, as the pH of cryptococcomas was found to be 5.4-5.6 in vivo. The supernatants were similar in composition, although metabolites in vns were generally present in higher concentrations. In addition, vgs contained two novel metabolites-acetoin and dihydroxyacetone. Polyphosphate was observed in cells from both varieties and may be a source of extracellular inorganic phosphate. Superoxide production in the presence of phorbol ester was enhanced by treatment with vns and decreased by vgs. At pH 5.5, vns caused high levels of necrosis in neutrophils, as well as increased adhesion/migration through A549 lung epithelial cell monolayers. Individual supernatant components such as polyols, acetoin, dihydroxyacetone, and gamma-aminobutyric acid exhibited both pro- and anti-inflammatory properties. Overall, we found that vgs was potentially less pro-inflammatory than vns. Inhibition of neutrophil function by products of CNVG may promote survival of extracellular organisms, and local multiplication to form cryptococcomas.

Animals↗
PubMed2002

Psychiatric and social outcomes of a rural district general hospital in the 1990s.

This study investigates the psychiatric and social outcomes of treatment by the psychiatric unit of a district general hospital in a semirural region of Australia. The study is a naturalistic investigation of a routine clinical service, and utilizes a longitudinal panel design. Repeat interviews at admission, 1 month and 1 year later were conducted with all consenting respondents (n = 57) with a diagnosis of schizophrenia, bipolar disorder or related condition, as well as with their nominated relatives. Patients showed significant improvements on clinical measures (P < 0.001) and a high rate of continuation of medication. Most measures of social functioning showed improvement although few were statistically significant. Patients and relative satisfaction was high. Relative worry showed significant improvement in the first month (P < 0.05). There was a high rate of readmission (31 patients) and mean days in hospital were also high at 43 days. These results suggest that basic district general hospital care, operating under both budgetary restrictions and the difficulties associated with recruiting staff can nonetheless provide a credible service. However, the results fall short of what research tells us can be achieved when services are adequately funded and more specifically targeted to meet patient needs.

Acute Disease↗
PubMed2002

A comparison of patient clinical and social outcomes before and after the introduction of an extended-hours community mental health team.

OBJECTIVE: The aim of this study was to assess the effectiveness of the addition of standard community treatment to a hospital-based service in a regional district of Australia. METHOD: The study was a naturalistic investigation of a routine clinical service and utilized a longitudinal panel design. Two matched groups of seriously mentally ill patients were recruited,one before the addition of the community mental health team (CMHT)and one after. Each sample was followed up for one year using a semistructured questionnaire and instruments including the Brief Psychiatric Rating Scale, the Global Assessment Scale, the Life Skills Profile and the Rosenberg Self-Esteem Scale as well as hospital records. RESULTS: Patients in both groups showed similar patterns of improvements. Although the aims of the new service included reducing in-patient utilization and improving social functioning,there were few significant differences between the two groups. While the number of admissions and length of stay were lower in the post-CMHTsample most were admitted rather than treated in their homes by the CMHT. CONCLUSION: The study concludes that better outcomes might have been achieved if the aims of the CMHT had been limited to either crisis or rehabilitation interventions, but not both. More attention needs to be paid to the service context in which model programmes are introduced so that new developments can be more closely tailored to the realities of what is likely to be achievable.

Adolescent↗