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Biomedical subjects

D A Marshall

Publications and source records attributed to D A Marshall.

At least 19 recordsLinked to original sources
PubMed2004

Cost-effectiveness of nucleic acid test screening of volunteer blood donations for hepatitis B, hepatitis C and human immunodeficiency virus in the United States.

BACKGROUND AND OBJECTIVES: The aim of this study was to examine the cost-effectiveness of adding nucleic acid testing (NAT) to serological (antibody and antigen) screening protocols for donated blood in the United States (US) with the purpose of reducing the risks of transfusion-transmission of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV). MATERIALS AND METHODS: The costs, health consequences and cost-effectiveness of adding either minipool or individual-donor NAT to serological screening (SS) testing were estimated using a decision-analysis model. RESULTS: With the given modelling assumptions, adding minipool NAT would avoid an estimated 37, 128 and eight cases of HBV, HCV and HIV, respectively, and save approximately 53 additional years of life and 102 additional quality adjusted life years (QALYs) compared with SS, at a net cost of $154 million. SS + minipool NAT - p24 compared with SS alone resulted in an incremental cost-effectiveness ratio of $1.5 million per QALY gained (range in sensitivity analysis $1.0-2.1 million per QALY gained) in this US analysis. CONCLUSIONS: The cost effectiveness of adding NAT screening is outside the typical range for most healthcare interventions, but not for established blood safety measures.

Blood Donors↗
PubMed2000

Measuring the effect of clinical guidelines on patient outcomes.

OBJECTIVES: To identify and examine the methodologic issues related to evaluating the effectiveness of treatment adherence to clinical guidelines. The example of antiretroviral therapy guidelines for human immunodeficiency virus (HIV) disease is used to illustrate the points. METHODS: Regression analysis was applied to observational HIV clinic data for patients with CD4+ cell counts less than 500 per microL and greater than 50 per microL at baseline (n = 704), using Cox proportional hazards time-varying covariates models controlling for baseline risk. The results are compared with simpler models (Cox model [without time-varying covariates] and logistic regression). In addition, the effect of including a measure of exposure to antiretroviral guidelines in the model is explored. RESULTS: This study has three implications for modeling clinical guideline effectiveness. To capture events that are time-sensitive, a duration model should be used, and covariates that are time-varying should be modeled as time-varying. Thirdly, incorporating a threshold measure of exposure to reflect the minimum period of time for guideline adherence required for a measurable effect on patient outcome should be considered. CONCLUSIONS: The methods proposed in this paper are important to consider if guidelines are to evolve from being a tool for summarizing and transferring the results of research from the literature to clinicians into a practical tool that influences clinical practice patterns. However, the methodology tested in this study needs to be validated using additional data on similar patients and using data on patients with other diseases.

Anti-HIV Agents↗
PubMed1997

Recommendations for the application of bone density measurement. What can you believe?

This study examined the conclusions of published reports that review the literature and make recommendations about appropriate applications of bone density measurement. It is based on a survey of 22 organizations producing such reports between 1986 and Spring 1995. Overall, the application of bone density measurement for the diagnosis of osteoporosis was supported by 65% of reports, by 44% for the monitoring and follow-up of patients with previously diagnosed disease, and by 59% for monitoring and follow-up of patients receiving treatment that may affect their bone density. A smaller proportion of reports from government and public organizations compared with other types of organizations and a smaller proportion of reports using more rigorous methods supported the applications for bone density measurement identified in the survey. A larger proportion of the reports published after 1990 compared with those published between 1986 and 1990 support the applications of bone density measurement, with the exception of population screening. The results of this survey suggest that there is considerable disagreement about the potential applications of bone density measurement. Publicly funded organisations and those using more rigorous methods tended to be more conservative in their conclusions.

Bone Density↗
PubMed1997

Pericardial involvement in systemic sclerosis.

OBJECTIVE: To determine the frequency and histological characteristics of pericardial involvement in systemic sclerosis. METHOD: Necropsy sections of pericardium from 44 patients with systemic sclerosis were studied, together with sections from 19 age/sex matched controls. Sections were stained with haematoxylin and eosin, acid toluidine blue, and elastic van Gieson. Mast cells were counted in 10 random high power fields and the degree of fibrosis was quantified using a Chalkley count. RESULTS: Chronic pericarditis was seen in 31 (77.5%) of the systemic sclerosis cases, but in only one of the controls. The characteristic changes of uraemic pericarditis were not seen. The degree of fibrosis was greater in those with systemic sclerosis, though numbers of mast cells, thought to be important in fibrogenesis, were similar in both groups. Myocardial fibrosis was seen in 15 (37.5%) of systemic sclerosis cases but in none of the controls. CONCLUSION: The incidence of pericarditis and myocardial fibrosis is much greater than in controls. The results indicate that pericarditis is a primary disease (rather than secondary to uraemia).

Adolescent↗
PubMed1993

Fatal disseminated intravascular coagulation complicating dental extraction.

A case is reported of fatal disseminated intravascular coagulation occurring 8 h after routine extraction of wisdom teeth in a 24-year-old woman. Since all bacteriological specimens taken were sterile and no other precipitant was found, we believe this case represents an example of the generalised Shwartzman reaction to the local trauma of dental extraction leading to fatal initiation of the coagulation system.

Adult↗
PubMed1992

Helmets! All the pros wear them.

OBJECTIVE: To assess the outcome of a multidisciplinary community campaign to increase helmet use and determine the success of a school education and helmet distribution program. DESIGN: Survey research. SETTING: Large metropolitan area and two elementary schools. PARTICIPANTS: Five hundred representative families in a metropolitan area and students enrolled in two elementary schools. INTERVENTIONS: A 1-year-long regional media campaign and a helmet distribution program in one elementary school after 4 weeks of safety instruction. RESULTS: Evaluation of the community component 1 year after initiation of the campaign revealed a 23% awareness of the promotion. Factors associated with wearing a helmet in the community included higher income levels, higher level of education, and male sex. The school component survey revealed that 73% of the children in school A reported helmet use vs 23% in school B. This multifaceted approach to affect helmet use demonstrated variable success in our community. CONCLUSION: This campaign effort achieved its greatest success in promoting community awareness of the importance of helmet use. However, further studies need to be performed to determine the success of the school education and helmet distribution program.

Bicycling↗
PubMed1992

Early aortic valve cusp rupture in relapsing polychondritis.

Aortic regurgitation associated with relapsing polychondritis usually occurs late in the disease as a result of aortic root dilatation. A case where aortic regurgitation occurred early and was due to cusp rupture with a normal aortic root is reported. The patient required urgent aortic valve replacement within six weeks of developing a murmur despite apparent control of inflammation with immunosuppressive treatment. The possibility of cusp rupture with sudden haemodynamic deterioration should be considered in patients with relapsing polychondritis who develop aortic regurgitation.

Aortic Valve↗
PubMed1992

Double blind, placebo controlled study of metronidazole as a disease modifying agent in the treatment of rheumatoid arthritis.

Anecdotal reports suggest that metronidazole may have disease modifying activity in the treatment of rheumatoid arthritis. To assess possible beneficial effects a double blind, comparative trial of metronidazole and placebo was performed. Fifty patients with active rheumatoid arthritis were randomly allocated to receive active drug (n = 24) or placebo (n = 26) and reviewed at weeks 0, 1, 4, 8, 12, 16, and 24. Detailed assessment of drug safety, biochemical and haematological parameters, and efficacy was made at these dates. Dose regimen was 400 mg twice daily from weeks 0 to eight, increasing to 400 mg three times a day from weeks nine to 24 provided that no adverse effects were recorded. Most patients were unable to tolerate metronidazole because of side effects or lack of efficacy, with only five (21%) continuing to take the drug at 24 weeks. For those patients attaining 12 weeks of treatment an overall improvement in articular index and morning stiffness was found. No improvement in laboratory indices of disease activity was seen, however. In this study metronidazole did not have disease modifying properties and was unacceptably toxic.

Adult↗
PubMed1990

Taste responses of dogs to ethylene glycol, propylene glycol, and ethylene glycol-based antifreeze.

Although it is widely believed that ethylene glycol-based antifreeze (AF) is an attractive tastant to dogs and other animals, empirical data on this point are not available. In experiment 1, we examined the propensity of 178 adult mixed-breed dogs to approach, sniff, and lick a concentration of AF commonly used in automotive cooling systems (50%). Despite the fact that most of the dogs approached and sniffed the AF in these 5-minute tests, only 9% initiated lick responses and most of these were brief and not followed by additional licking. In experiment 2, the lick responses of five gastric-cannulated dogs to aqueous solutions of 20% sucrose, 50% ethylene glycol, 50% propylene glycol, water, and 50% AF were examined in 14-minute tests before and after periods of food and water deprivation. Under the latter conditions, 2 of the 5 dogs drank amounts of ethylene glycol that would have been lethal to uncannulated dogs. None of the five dogs drank potentially lethal amounts of AF. The preference order for these tastants was sucrose greater than water greater than ethylene glycol greater than AF = propylene glycol. Although these findings question the general belief that AF is highly palatable to most dogs, they do imply that large individual differences in responsiveness exist and that AF ingestion is likely influenced by motivational state. Furthermore, they suggest the possibility that unpleasant-tasting additives could be successfully developed to eliminate the ingestion of AF, because the initial attractiveness of AF is relatively low. Such additives would have to be stable in vehicular cooling systems and not adversely affect the functional aspects of AF performance.

Animals↗
PubMed1990

Occlusive dressings. Does dressing type influence the growth of common bacterial pathogens?

We studied the effect of different occlusive dressings and of air exposure on the growth of four pathogenic bacteria in wounds. Partial-thickness wounds on domestic pigs were inoculated with Staphylococcus aureus, Clostridium perfringens, Bacteroides fragilis, or Pseudomonas aeruginosa. Each wound was covered with three dressings (DuoDERM, Opsite, or Vigilon), or left exposed to air. Groups of wounds were sampled at 24, 48, and 72 hours. Staphylococcus aureus reached high levels beneath all of the dressings and in the air-exposed wounds. The numbers of C perfringens and B fragilis were greatly reduced in the air-exposed wounds and slightly reduced in the Opsite-covered wounds. The numbers of P aeruginosa were greatest in the Opsite- and Vigilon-covered wounds. The results indicate that occlusive dressings are not indicated in wounds that clinically appear to be grossly contaminated or that may contain anaerobic organisms.

Animals↗
PubMed1990

Ethics committees in Canadian hospitals: report of the 1989 survey.

A survey of English-language hospitals with more than 300 beds in Canada was conducted in 1989 to assess institutional ethics committees. A dramatic increase was found in the growth of such committees, compared with a similar survey taken in 1984. The growth and the activities of institutional ethics committees are discussed, noting the need for more attention for research on their effectiveness.

Canada↗