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At least 91 records · Page 5Linked to original sources
PubMed1996

Serum antibodies against Borrelia afzelii, Borrelia burgdorferi sensu stricto and the 41-kiloDalton flagellin in patients from a Lyme borreliosis endemic area: analysis by EIA and immunoblot.

To evaluate the possible importance of antigenic heterogeneity in the serological diagnosis of Lyme borreliosis a study was performed using antigens from various Lyme Borrelia strains. Serum samples from 102 patients with clinical signs of the infection, all living in an endemic area in southern Sweden, were evaluated by four enzyme immuno assays (EIA). The sera were initially tested for the immunoglobulin G response to antigens from a local Borrelia afzelii strain (ACA1). Serum samples from healthy blood donors residing in the same region were used to define seropositivity in the ACAI-EIA. Immunoblotting was performed with the ACAI antigen and the reactive bands were analysed. A serum was defined as positive when at least four of the Borrelia specific polypeptides (OspC, OspA, OspB, p39, p41 [flagellin], p83, p94, 110kDa) were stained. The same sera were then analysed in three other IgG enzyme immunoassays, one based on antigens from Borrelia burgdorferi sensu stricto B31, and another on pooled protein fractions from strains B31 and ACAI. In the third EIA, sera were analysed for antiflagellin reactivity (B, afzelii strain DK-1). An inconstant immune response was demonstrated in the EIAs and the seropositivity varied between 30-47% when low positive values were excluded, and between 38-73% if all values were included. Fifty sera (50/102) met the criteria for a positive immunoblot, but positive immunoblots were detected with both low positive and negative sera independent of antigen used in the EIAs. Antigens of the local B. afzelii strain were found to detect a higher number of seropositive individuals, which suggests that the antibody reactivity to Lyme Borrelia increases when antigens from a strain endemic in a particular geographical region are used. Data from this study suggest that EIA alone seems insufficient for the serodiagnosis, and antigenic heterogeneity of Lyme Borrelia spp. influences the performance of serum antibody tests. The reliability of serological assays could be increased when the serum antibodies against antigens of Borrelia spp. predominant in the local geographical region are measured.

Antigens, Bacterial↗
PubMed1990

Small-area analysis of gastrointestinal disease hospital discharge variation: are the poor at risk?

Capitation plans may place their enrollees at risk of rationed services if they do not adjust for underlying patient characteristics that dictate differing levels of care. To assess the degree to which population-based socioeconomic characteristics are associated with hospital use, this study explored small-area variation in hospital discharges for gastrointestinal and liver (GI) Diagnosis Related Groups (DRGs). Utilizing a 1980 Michigan database of 1.5 million discharges, we constructed age-adjusted, population-based discharge rates for the GI DRGs. We then evaluated the effect of poverty, defined by the percent of households in a hospital market community below the poverty line. Using regression techniques, we found that poverty explained 27.5% of the variation in GI hospital discharges, with the poor admitted more often (p less than 0.0001). Using cost weighted discharge rates as the dependent variable, we found that poverty explained 20.3% (p = 0.0003) of the variation in cost weighted discharges. These results suggest that poverty explains a significant amount of variation in hospital discharges and has a significant effect on associated small-area hospitalization costs in GI diseases. Practicing gastroenterologists and surgeons need to be aware of factors that influence patients utilizing their services in order to retain their role as patient advocates as changes in payment systems are suggested.

Capitation Fee↗
PubMed1986

Etiology of pure tricuspid regurgitation based on anular circumference and leaflet area: analysis of 45 necropsy patients with clinical and morphologic evidence of pure tricuspid regurgitation.

Despite recent renewed interest in the detection of tricuspid valve regurgitation by echocardiographic and Doppler techniques, little morphologic information is available on dysfunctioning tricuspid valves. This report describes 45 necropsy patients with clinical and morphologic evidence of pure (no element of stenosis) tricuspid regurgitation and provides morphometric observations (anular circumference, leaflet area) of the tricuspid valve useful in determining the etiology of pure tricuspid regurgitation. Of 45 patients, 24 (53%) had pure tricuspid regurgitation resulting from an anatomically abnormal valve (prolapse in 7, papillary muscle dysfunction in 6, rheumatic disease in 5, Ebstein's anomaly in 3, infective endocarditis in 2, carcinoid tumor in 1), and 21 (47%) had an anatomically normal valve with systolic pulmonary artery hypertension (cor pulmonale in 12, mitral stenosis in 9). Anular circumference was dilated (greater than 12 cm) in patients with various causes of pulmonary hypertension, floppy valve and Ebstein's tricuspid anomaly. Leaflet area was increased in floppy valve and Ebstein's anomaly. Of the 45 patients, 24 had pulmonary systolic artery pressure measurements available for correlation with tricuspid valve morphology. Pulmonary artery pressures accurately predicted morphologically normal from abnormal valves in 16 patients (89%). Morphologic overlap occurred in six patients with pulmonary pressures of 41 to 54 mm Hg. Of these six, the additional knowledge of normal or dilated anular circumference correctly separated valves with normal and abnormal leaflets.

Adolescent↗
PubMed1988

Improving perinatal outcome through data management: the design of the small area analysis system.

The decentralization of health management requires that appropriate tools be developed for decision support at the local level. The Improved Pregnancy Outcome Data Management System (IPODM) was designed to enable health managers and physicians with little computer experience to access over 500 variables derived from United States Census and California Vital Statistics sources. Using an interactive format one can create datasets describing the sociodemographic composition and perinatal outcome of individuals residing in individual census tracts (or zip codes) and in aggregates of these basic units such as neighborhoods, health catchment areas, or municipal districts. IPODM allows one to analyze this information in terms of tables, plots, maps, and basic statistical procedures using an interactive format. This paper describes the system designed for the State of California and the principles that guided the design.

Database Management Systems↗
PubMed2001

Endovascular brachytherapy: dosimetry and dose-area analysis of various radiation sources.

With the increase in popularity of endovascular brachytherapy for prevention of restenosis following coronary angioplasty, it remains to be determined which isotope and isotope form is the most ideal. An issue concerning the use of wire sources is the influence of the centering of the wire on dose uniformity across the artery wall and the potential problems this can lead to in terms of underdosage of the target tissues. In this investigation, the dosimetric characteristics of three currently used sources (gamma-emitting 192Ir wire; beta-emitting 32P wire; and beta-emitting 188Re solution) were determined with EGS4 Monte Carlo. The dose results were then used to determine the dose-area relationships for the three sources in arteries with concentric and non-concentric lumens/walls, including situations in which the wire sources are moved away from the centre of the artery. It is found that, in order to ensure dose uniformity, centering is substantially more important for beta-emitting wire sources. This is highlighted most significantly in the case of an example large irregular artery. Although the suitability of a source depends on many criteria (e.g., cost, availability, radiation protection, possible radiation-induced late effects), the problem of centering a wire source in possibly large and/or irregular arteries is greatly eased by the use of a gamma-emitting source.

Angioplasty, Balloon, Coronary↗
PubMed2004

XAFS imaging of Tsukuba gabbroic rocks: area analysis of chemical composition and local structure.

Gabbroic rocks were collected at Mount Tsukuba in Japan, and their XAFS images were studied using a projection-type X-ray fluorescence (XRF) microscope, which is a powerful new tool recently developed for extremely rapid imaging. The instrument employs a grazing-incidence arrangement in order that primary X-rays illuminate the whole sample surface, as well as parallel-beam optics and an extremely close geometry in order to detect XRF by a high-performance X-ray CCD system with 1024 x 1024 pixels. The XRF image indicated that black amphibole and white feldspar, both of which are typical mineral textures of the rock, contain iron. The origin has been suggested to be several small yellowish-brown minerals contained there. The XAFS imaging has been carried out by repeating the exposure of XRF images during the energy scan of the primary X-rays. It has been found that the structure is qualitatively close to that of olivine, and the main differences found in both areas can be explained as a difference in iron and magnesium concentration, i.e. the mixed ratio of forsterite (Mg(2)SiO(4)) and fayalite (Fe(2)SiO(4)). The feasibility of the present XAFS imaging method has been demonstrated for realistic inhomogeneous minerals.

Altitude↗
PubMed1991

Small area analysis of hospital discharges for musculoskeletal diseases in Michigan: the influence of socioeconomic factors.

PURPOSE: The rise in health care costs has occasioned a number of initiatives in an attempt to reduce the rate of increase. Despite the growth of health maintenance organizations and preferred provider organizations and the introduction of Medicare's prospective payment system, health care costs have continued to increase. Coincident with these efforts, a number of researchers have shown that there exists wide variation in age-adjusted hospital discharge rates, which translate into significant variation in per capita expenditures. Much of the focus on the reasons for hospital admission variability has been on physician practice variation. If most of the variation in hospital discharge rates is due to physician practice style, then payment systems can be developed (e.g., capitation) that limit physician practice variation without harming patients. We examined socioeconomic factors in Michigan communities to assess their association with hospital discharge rates for patients with musculoskeletal diseases. PATIENTS AND METHODS: Data on hospital discharges from 1980 and 1987 were taken from the Michigan Inpatient Data Base. All admissions from the major diagnostic category 8, diagnosis-related group (DRG) 209-256 were included. Zip code-specific hospitalization data were grouped into small geographic areas or hospital market communities (HMCs). Discharge rates were calculated, and profiles of the socioeconomic characteristics of each of the HMCs were developed. A Poisson regression model with an extrasystematic component of variance was used to analyze the association of HMC socioeconomic characteristics with age-adjusted hospital use. RESULTS: We found that four socioeconomic variables, average annual income per capita, percent of the population with four years of college, percent of the population living in an urban area, and percent of families with incomes below the poverty line, explained 26.6% (R2) of the variation in overall hospital discharge rates (p less than 0.001). Moreover, we found that the ability of the model to explain variability was influenced by the type of disease, and that these socioeconomic variables had a consistent effect across the range of DRGs. Finally, we noted that, over the period of 1980 to 1987, socioeconomic factors remained important in explaining hospital use despite the dramatic changes in the delivery of care over this period. CONCLUSION: Socioeconomic factors play a significant role in explaining the observed variation in hospital discharge rates for musculoskeletal diseases. Models utilizing only physician practice variation to account for the population-based differences in discharge rates are overly simplistic. In order to ensure that vulnerable subsets of the population are not harmed by the introduction of cost-containment strategies based on simplistic models, more attention must be paid to the socioeconomic and epidemiologic factors related to hospital use.

Bone Diseases↗
PubMed1991

Determinants of psychiatric rehospitalization: a social area analysis.

The purpose of this paper is to develop an analytic framework and methodology for estimating the demand for psychiatric hospitalization in state facilities, either new admissions or readmissions of clients from the Community Services Boards (CSBs) of Virginia. The combination of community and organizational factors with inpatient characteristics for the CSBs can help identify pertinent predictors of psychiatric hospitalization. Review of the literature on psychiatric epidemiology shows that the predictors of psychiatric hospitalization can be classified into four major dimensions including community resources, socio-demographic factors, CSB client characteristics, and CSB organizational factors. It is postulated that the rates of first admissions and readmissions to state facilities are influenced by four dimensions. Furthermore, the variation in readmissions rates is contingent upon previous first admission rates and the average length of stays in state institutions while other conditions-such as community resources and demographics, CSB client mix, and CSB organizational factors-are simultaneously considered. The data were compiled from multiple sources. A path analytic model, using a linear structural relations program (LISREL VI), was validated. After the model was carefully fitted, the estimation equations for the rates of first admissions and readmissions were finalized. The estimates for psychiatric hospitalization, both first- and re-admissions, were made for each of the study CSBs.

Health Services Accessibility↗
PubMed1999

Alcohol availability and homicide in New Orleans: conceptual considerations for small area analysis of the effect of alcohol outlet density.

OBJECTIVE: To determine the geographic relation between homicide rate and two competing measures of exposure to alcohol outlets, alcohol outlets per square mile and alcohol outlets per person. METHOD: Homicides occurring in 1994 and 1995 and on-sale and off-sale alcohol outlets with active 1995 licenses were geocoded by address for aggregation at the census tract level. Ecologic analysis of the 155 urban residential census tracts in New Orleans was conducted with controls for potential sociodemographic confounders (% black, % adults unemployed, % unmarried households, and ratio males 15-24/males 35-44). RESULTS: After logarithmic transformation of all study variables, sociodemographic confounders alone accounted for 58% (R2 = .58) of the variance of homicide rates. Adding off-sale alcohol outlet density to the models, measured (beta +/- SE) either as outlets per square mile (beta = .211 +/- .062) or outlets per person (beta = .244 +/- .063), yielded strong geographic relations with homicide and increased the amount of variance explained (R2 = .62). A 10% higher off-sale outlet density accounted for a 2.4% higher homicide rate. CONCLUSIONS: Both off-sale alcohol outlets per square mile and off-sale outlets per person demonstrate strong geographic associations with homicide rates among urban residential census tracts in New Orleans. These findings suggest that communities faced with high rates of assaultive violence might consider policy interventions that address alcohol outlet related factors.

Adolescent↗