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Biomedical subjects

M Brownell

Publications and source records attributed to M Brownell.

14 recordsLinked to original sources
PubMed2005

Evaluation of antibiotic resistance analysis and ribotyping for identification of faecal pollution sources in an urban watershed.

AIMS: The accuracy of ribotyping and antibiotic resistance analysis (ARA) for prediction of sources of faecal bacterial pollution in an urban southern California watershed was determined using blinded proficiency samples. METHODS AND RESULTS: Antibiotic resistance patterns and HindIII ribotypes of Escherichia coli (n = 997), and antibiotic resistance patterns of Enterococcus spp. (n = 3657) were used to construct libraries from sewage samples and from faeces of seagulls, dogs, cats, horses and humans within the watershed. The three libraries were analysed to determine the accuracy of host source prediction. The internal accuracy of the libraries (average rate of correct classification, ARCC) with six source categories was 44% for E. coli ARA, 69% for E. coli ribotyping and 48% for Enterococcus ARA. Each library's predictive ability towards isolates that were not part of the library was determined using a blinded proficiency panel of 97 E. coli and 99 Enterococcus isolates. Twenty-eight per cent (by ARA) and 27% (by ribotyping) of the E. coli proficiency isolates were assigned to the correct source category. Sixteen per cent were assigned to the same source category by both methods, and 6% were assigned to the correct category. Addition of 2480 E. coli isolates to the ARA library did not improve the ARCC or proficiency accuracy. In contrast, 45% of Enterococcus proficiency isolates were correctly identified by ARA. CONCLUSIONS: None of the methods performed well enough on the proficiency panel to be judged ready for application to environmental samples. SIGNIFICANCE AND IMPACT OF THE STUDY: Most microbial source tracking (MST) studies published have demonstrated library accuracy solely by the internal ARCC measurement. Low rates of correct classification for E. coli proficiency isolates compared with the ARCCs of the libraries indicate that testing of bacteria from samples that are not represented in the library, such as blinded proficiency samples, is necessary to accurately measure predictive ability. The library-based MST methods used in this study may not be suited for determination of the source(s) of faecal pollution in large, urban watersheds.

Animals↗
PubMed2004

A framework for modelling differences in regional mortality over time.

STUDY OBJECTIVE: To present a conceptual framework for testing differences in mortality for small geographical areas over time using the generalised linear model with generalised estimating equations. This framework can be used to test whether the magnitude of regional inequalities in health status has changed over time. DESIGN: A Poisson regression model for correlated data is used to investigate the relation of population health status to demographic, geographical, and temporal explanatory variables. Differences between regions at one or more points in time are tested with linear contrasts. SETTING AND PARTICIPANTS: A case example shows the application of the framework. All cause mortality and cause specific mortality were compared for three rural regions of Manitoba, Canada between 1985 and 1999. The data were obtained from Vital Statistics records and the provincial health registry. MAIN RESULTS: Tests of linear contrasts on the regression coefficients for time and region show an increase in the magnitude of the difference in the risk of all cause mortality and heart disease mortality between northern and southern regions of the province for the 1985-1989 and 1995-1999 time periods. No significant differences are identified for cancer, injury, or respiratory disease mortality. CONCLUSIONS: The proposed framework enables testing of a variety of hypotheses about differences between regions and time periods and can be applied to other measures of population health status.

Health Status↗
PubMed2001

Epidemiology of varicella zoster virus infection in Canada and the United Kingdom.

Many countries are currently studying the possibility of mass vaccination against varicella. The objective of this study was to provide a comprehensive picture of the pre-vaccine epidemiology of the varicella zoster virus (VZV) to aid in the design of immunization programs and to adequately measure the impact of vaccination. Population-based data including physician visit claims, sentinel surveillance and hospitalization data from Canada and the United Kingdom were analysed. The key epidemiological characteristics of varicella and zoster (age specific consultation rates, seasonality, force of infection, hospitalization rates and inpatient days) were compared. Results show that the overall epidemiology of varicella and zoster is remarkably similar between the two countries. The major difference being that, contrary to Canada, the epidemiology of varicella seems to be changing in the United Kingdom with an important decrease in the average age at infection that coincides with a significant increase in children attending preschool. Furthermore, differences exist in the seasonality between the United Kingdom and Canada, which seem to be primarily due to the school calendar. These results illustrate that school and preschool contact patterns play an important role in the dynamics of varicella. Finally, our results provide baseline estimates of varicella and zoster incidence and morbidity for VZV vaccine effectiveness and cost-effectiveness studies.

Adolescent↗
PubMed2001

Vancomycin-resistant Enterococcus spp. isolated from wastewater and chicken feces in the United States.

Vancomycin-resistant Enterococcus spp. (VRE) were isolated from sewage and chicken feces but not from other animal fecal sources (dog, cow, and pig) or from surface waters tested. VRE from hospital wastewater were resistant to > or =20 microg of vancomycin/ml and possessed the vanA gene. VRE from residential wastewater and chicken feces were resistant to 3 to 5 microg of vancomycin/ml and possessed the vanC gene.

Animals↗
PubMed1999

A comparative study of the costliness of Manitoba hospitals.

OBJECTIVES: In light of ongoing discussions about health care policy, this study offered a method of calculating costs at Manitoba hospitals that compared relative costliness of inpatient care provided in each hospital. RESEARCH DESIGN: This methodology also allowed comparisons across types of hospitals-teaching, community, major rural, intermediate and small rural, as well as northern isolated facilities. MEASURES: Data used in this project include basic hospital information, both financial and statistical, for each of the Manitoba hospitals, hospital charge information by case from the State of Maryland, and hospital discharge abstract information for Manitoba. The data from Maryland were used to create relative cost weights (RCWs) for refined diagnostic related groups (RDRGs) and were subsequently adjusted for Manitoba length of stay. These case weights were then applied to cases in Manitoba hospitals, and several other adjustments were made for nontypical cases. This case mix system allows cost comparisons across hospitals. RESULTS: In general, hospital case mix costing demonstrated variability in hospital costliness, not only across types of hospitals but also within hospitals of the same type and size. CONCLUSIONS: Costs at the teaching hospitals were found to be considerably higher than the average, even after accounting for acuity and case mix.

Bed Occupancy↗
PubMed1998

Managing health services: how administrative data and population-based analyses can focus the agenda.

University-based researchers in Manitoba, Canada, have used administrative data routinely collected as part of the national health insurance plan to design an integrated database and population-based health information system. This information system is proving useful to policymakers for providing answers to such questions as: which populations need more physician services? Which need fewer? Are high-risk populations poorly served or do they have poor health outcomes despite being well served? Does high utilization represent overuse or utilization related to high need? More specifically, this system provides decision-makers with the capability to make critical comparisons across regions and subregions of residents' health status, socioeconomic risk characteristics, and use of hospitals, nursing homes, and physicians. The system permits analyses of demographic changes, expenditure patterns, and hospital performance in relation to the population served. The integrated database has also facilitated outcomes research across hospitals and counties, utilization review within a single hospital, and longitudinal research on health reform. A particularly interesting application to planning physician supply and distribution is discussed. The discussion highlights the strengths of integrated population-based information in analyzing the health care system and raising important questions about the relationship between health care and health.

Canada↗
PubMed1997

Relationship of nonstaging pathological risk factors to lymph node metastasis and recurrence in clinical stage I endometrial carcinoma.

OBJECTIVE: To determine if DNA ploidy, hormone receptors, vascular space invasion (VSI), perivascular lymphocytes (PVL), and the oncogenes HER-2/neu, p53, and bcl-2 are independent prognostic indicators for lymph node metastasis and cancer recurrence in clinical stage I endometrial carcinoma. METHODS: Among 349 patients with clinical stage I endometrial cancer 31 patients either had lymph node metastases when surgically staged or developed recurrent cancer. Using a case-control matched-pair technique, controls were selected for each of 24 cases by matching for age, histological grade, depth of myometrial invasion, performance of node dissection, and use of adjuvant radiation therapy. In a blinded fashion a pathologist reviewed all histopathology, and all molecular tests were performed on paraffin-embedded tissue samples. Statistical analysis was performed by chi2 and McNemar's tests. RESULTS: VSI was the only histopathological factor significantly related to positive lymph nodes and cancer recurrence (P = 0.01), independent of grade and myometrial invasion. Aneuploidy, oncogene expression (p53, HER-2/neu, bcl-2), and hormone receptors were not significantly related to lymph node metastasis and cancer recurrence. CONCLUSIONS: The presence of vascular space invasion is a pathological factor independently associated with a risk of nodal metastasis and cancer recurrence in clinical stage I endometrial cancer. DNA ploidy, oncogene expression, and hormone receptor status do not have more predictive value than standard staging pathological criteria.

Aged↗
PubMed1994

Introducing data into the health policy process: developing a report on the efficiency of bed use in Manitoba.

The Manitoba Centre for Health Policy and Evaluation (MCHPE) is a university-based centre funded by the provincial government to provide analyses for use in policy development and management of the health care system. At the government's request, the MCHPE undertook an analysis of bed use in the major hospitals in the province. This article reviews the formulation, execution and delivery of the project to illustrate how health services researchers, administrative data and key actors in the health care system can interact in the policy process.

Bed Occupancy↗
PubMed1992

Splenic involvement by aggressive malignant lymphomas of B-cell and T-cell types. A morphologic and immunophenotypic study.

To determine whether there are any consistent morphologic differences between B-cell and T-cell aggressive non-Hodgkin's lymphomas of the spleen, the authors analyzed 16 spleens involved by mixed cell (1 case) or large cell (15 cases) lymphomas. Immunologic data were derived from cell suspensions or frozen tissue in each case. Five cases had a T-cell phenotype, and 11 were B-cell. Morphologic features favoring a T-cell phenotype included epithelioid histiocytic reactions, confinement of the lymphomas to the splenic T-zones (periarteriolar lymphoid sheath and marginal zone), and clear cell or polymorphous cytologic features. Features favoring a B-cell phenotype included multiple discrete nodules in the white pulp, large coalescent tumor nodules in association with small lymphocytic lymphoma, and large non-cleaved or immunoblastic plasmacytoid cytologic characteristics. Four cases were unusual because most neoplastic large cells were distributed diffusely or formed only small aggregates in the red pulp without definite tumor masses or nodules involving the white pulp. Because of this distribution and the frequently encountered erythrophagocytosis by benign-appearing histiocytes, these cases resembled malignant histiocytosis. A T-cell phenotype was predicted for all four cases; however, only one case, a lymphoma with polymorphous cytologic characteristics, was of T-cell lineage. The other three cases were of B-cell lineage. The authors' results indicate that in most instances the B-cell or T-cell nature of aggressive splenic lymphomas is predictable from the distributional and cytologic features. As in lymph nodes, there are cases for which the morphologic characteristics of B-cell and T-cell lymphomas are indistinguishable.

Adult↗
PubMed1986

Non-Hodgkin's lymphomas following radiation therapy alone for Hodgkin's disease.

We have recently treated three patients who developed a non-Hodgkin's lymphoma after therapy with radiation alone for Hodgkin's disease. The secondary non-Hodgkin's lymphomas occurred 4 years (two patients) and 11.5 years after receiving irradiation. Thirteen additional cases have been reported and are reviewed with attention to the subsequent histology and response to treatment of these secondary non-Hodgkin's lymphomas. The pathogenesis is unknown, but, may be therapy-related or part of the natural history of the lymphocyte predominance subtype of Hodgkin's disease. Possible mechanisms will be discussed. A subset of the patients with secondary lymphomas following radiation therapy alone are curable with chemotherapy. New sites of disease after apparent control of Hodgkin's disease require pathology for confirmation of the disease process and appropriate therapy.

Adult↗