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Biomedical subjects

J Patten

Publications and source records attributed to J Patten.

17 recordsLinked to original sources
PubMed2005

The effects of sediment size fraction and associated algal biofilms on the kinetics of phosphorus release.

Experiments using flumes containing sediment of three different size fractions, from two sites on the River Tame, investigated the influences of sediment particle size, and an associated biofilm, on sediment-water exchanges in heterogeneous sediment deposits. This is the first study undertaken to understand the kinetics of the release of soluble reactive phosphorus from sediments of natural systems to identify which of the size compartments affected those fluxes most. Samples of fine material (<2 mm), gravel (2-20 mm), and stones (>20 mm) were collected over a period of several weeks and brought to a fluvarium where they were placed in artificial, controlled flow, and flume channels. Synthetic solutions of similar ionic strength to the river were prepared using calcium chloride. Temperature, pH, and dissolved oxygen of the solution overlying the sediment were monitored automatically whilst filtered samples were obtained at 2 h intervals over 48 h. The biomass, expressed as mg m(-2) chlorophyll a, of the algal component of the biofilm from the surface of the sediment was estimated using methanol extraction. Differences in the responses were observed between the sediment size fractions and the two sites, where contaminant concentrations varied. The equilibrium phosphate concentration and a phosphorus transfer index were used to establish that there was a net uptake of phosphorus by all three sediment size fractions, from both sites, at the time of sampling. The kinetic results showed very fast initial reactions of phosphorus release from the larger size fractions with a well-developed filamentous algal growth present implying a different mechanism than diffusion being involved. The stones and associated biofilms also released more phosphorus than the fine fraction, e.g. final release concentrations for the most contaminated site were: fines approximately 2.5 microM, gravel approximately 6.5 microM, and stones approximately 65.0 microM (expressed as soluble reactive phosphorus). Phosphorus fluxes, calculated assuming the concentration of phosphorus in the sediment was less than the equilibrium concentration, were a maximum at the most contaminated site, e.g. fines 6.4 nmol m(-2) s(-1), gravel 27 nmol m(-2) s(-1), and stones 109 nmol m(-2) s(-1) (normalised with respect to the river bed area). These results confirm that sediment having a biofilm and associated particulate material results in a greater flux than fine sediment, which does not support a filamentous biomass. Removal of the fine particulates trapped in the algal growth reduced soluble phosphorus release. These factors demonstrate that both gravel and stone substrates have an important control over the release of soluble reactive phosphorus.

Biofilms↗
PubMed2004

Screening for syphilis among men who have sex with men in various clinical settings.

OBJECTIVES: To assess the prevalence of syphilis infections among men who have sex with men (MSM) accessing the Brisbane Sexual Health Clinic during the period 1997 up to May 2003, data were collated through three clinical programmes conducted by the service-a large inner city mainstream sexual health clinic and two small outreach sessional clinics conducted on the site of male sex on premises venues (SOPV). Data analysis also provided the opportunity to evaluate the effectiveness of the smaller outreach clinics to access populations of MSM less likely to attend or identify at the larger mainstream clinic, and therefore enhance the detection of previously undiagnosed sexually transmissible infections. METHODS: Computerised records from 1997-2003 were collated for a statistical analysis of syphilis and other STI pathology results for all MSM accessing the mainstream clinic, and two outreach clinics. RESULTS: A review of client charts showed that 16 new syphilis diagnoses were made over the previous 5 years, but only two of these infections (both through the mainstream clinic) were early syphilis and therefore transmissible. All other cases were latent infections. A higher proportion of bisexual men was identified with positive syphilis serology but this was just below significance (p=0.06). Significantly, almost a third of syphilis diagnoses (all latent) were made at SOPV outreach clinics, despite the much lower proportion of clients seen overall through the SOPV clinics. For other sexually transmissible infections, the mainstream clinic demonstrated greater efficiency at case detection. CONCLUSION: Outreach clinics located in male saunas may serve an effective function in syphilis screening by facilitating access for a particular subpopulation of MSM (bisexual, married men). These outreach clinics may provide important outlets for education and opportunistic screening of asymptomatic MSM and foster a greater willingness for men to honestly self identify. However, larger, mainstream clinics serve a more anonymous venue for the testing of symptomatic men.

Adolescent↗
PubMed2001

Time trends in HIV incidence among homosexually active men seen at sexual health clinics in Australia, 1993-1999.

BACKGROUND: Increases in sexual risk behaviour have recently been reported among homosexually active men in Australia and in other industrialised countries, potentially facilitating an increase in HIV incidence. OBJECTIVE: To monitor HIV incidence among homosexually active men seen through a network of sexual health clinics in Australia. STUDY DESIGN: Selected metropolitan public sexual health clinics provided counts of the number of people seen at the clinics during a calendar year, the number voluntarily tested for HIV antibody and the number newly diagnosed with HIV infection, broken down by sex, age group, HIV exposure category and HIV antibody testing history. HIV incidence was estimated among homosexually active men with a history of a negative test in the 12 months prior to last being seen in a calendar year. RESULTS: Of 23924 men seen at the clinics in 1993-1999 with a reported history of male homosexual contact, 7440 (31.1%) had a negative test in the 12 months prior to last being seen in a calendar year. The percentage of men with a recent negative test declined significantly over time, from more than 33% in 1994-1996 to 29% in 1999 (P=0.003), and with increasing age, from 34.3% among men aged 25-29 years to 27.4% among men aged 40 years or older (P<0.0005). A total of 5346 (71.9%) men were retested for HIV antibody within 12 months of the last negative test. The percentage of men retested declined significantly over time, from 77.8% in 1994 to 67.2% in 1999 (P=0.021) but did not change by age group (P=0.132). Overall, 56 men were newly diagnosed with HIV infection. Estimated HIV incidence was 2.1% in 1993-1999; incidence did not change significantly by year (P=0.498) or age group (P=0.757). CONCLUSION: HIV incidence has remained stable among homosexually active men seen through a network of sexual health clinics in Australia.

Adolescent↗
PubMed1998

The costs and cost-effectiveness of unrelated donor bone marrow transplantation for chronic phase chronic myelogenous leukemia.

Unrelated donor transplantation prolongs survival in some patients with chronic myelogenous leukemia (CML) in chronic phase. However, there are growing concerns about the intensive resources required for this procedure given health care budget constraints. To address this issue, we conducted a study of the costs and cost-effectiveness of unrelated donor transplantation for chronic phase CML. The costs of transplantation were derived from 157 patients from the Brigham and Women's Hospital (BWH) and the Fred Hutchinson Cancer Research Center (FHCRC). Estimates of the effectiveness of transplantation were taken from our previous work using data from the International Bone Marrow Transplant Registry and the National Marrow Donor Program. The median cost of the first 6 months of care including donor identification, marrow collection, patient hospitalization for transplantation and all outpatient medications and readmissions through 6 months postmarrow infusion was $178,500 (range, $85,000 to $462,400) and the mean was $196,200. Mean costs for patients surviving beyond 6 months posttransplant were significantly lower than for patients dying within that period ($189,700 v $211,000, respectively, P =.03). Posttransplant follow-up costs were high for months 6 to 18, then decreased. The incremental cost-effectiveness of transplantation within 1 year of diagnosis versus -interferon therapy without transplant in the base case of a 35-year-old patient was $51,800/quality-adjusted life year (QALY) gained. Sensitivity analysis showed that most ratios were between $50,000 to $100, 000/QALY or within the intermediate zone of acceptable cost-effectiveness ratios.

Adolescent↗
PubMed1985

The Scrooge issue.

Explore the source record for details and available documents.

State Medicine↗
PubMedDate not supplied

Head CT in new geriatric psychiatry patients: a prospective study.

Computed tomography of the head (HCT) was studied prospectively in 42 new geriatric psychiatry patients. Scans were obtained in 88% of the sample. Subjects underwent a complete evaluation by a geriatric psychiatrist who was blind to the HCT results. The HCT was abnormal in 32 (86%) of the 37 patients who had a scan. The most frequent finding was atrophic changes, which were discovered in ten (27%) of the 37 patients. Subcortical vascular disease was found in 14 patients (38%). Mixed pictures with both vascular disease and atrophic changes were found in nine (24%). The only statistically significant predictor of an abnormal HCT was an abnormal neurobehavioral examination. While the information gained from the HCT did not add appreciably to the clinical evaluation in determining whether there was an organic or idiopathic psychiatric syndrome, it was crucial in determining the location and nature of the central nervous system lesions.

Aged↗
PubMedDate not supplied

A case study in evidence-based wound management.

On the first of July 1998, Frank Dobson, the then Secretary of State for Health, revealed the consultation document 'A First Class Service' (Department of Health (DoH), 1998). This article describes a wound management case study which showed how a first class service was provided for a patient with very severe pressure ulcers and complex medical problems. A multiprofessional approach to her complex and challenging problems was maintained. Evidence-based guidelines for the prevention and management of pressure damage were followed, supported by modern researched-based wound management and pressure relief. In addition, risk management strategies were observed, and provided the basis for planning and evaluating her individualized care.

Evidence-Based Medicine↗