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Biomedical subjects

A Clark

Publications and source records attributed to A Clark.

At least 343 records · Page 19Linked to original sources
PubMedDate not supplied

Disease mapping models: an empirical evaluation. Disease Mapping Collaborative Group.

The analysis of small area disease incidence has now developed to a degree where many methods have been proposed. However, there are few studies of the relative merits of the methods available. While many Bayesian models have been examined with respect to prior sensitivity, it is clear that wider comparisons of methods are largely missing from the literature. In this paper we present some preliminary results concerning the goodness-of-fit of a variety of disease mapping methods to simulated data for disease incidence derived from a range of models. These simulated models cover simple risk gradients to more complex true risk structures, including spatial correlation. The main general results presented here show that the gamma-Poisson exchangeable model and the Besag, York and Mollie (BYM) model are most robust across a range of diverse models. Mixture models are less robust. Non-parametric smoothing methods perform badly in general. Linear Bayes methods display behaviour similar to that of the gamma-Poisson methods.

Algorithms↗
PubMedDate not supplied

Effects of colchicine on the gallbladder of the mouse.

The effects of colchicine on the mouse gallbladder followed a course depending on the dosage given (0.4-4 mg/100 g body weight). Following 0.5 mg/100 g, by 16 h there was a marked cholestasis with dilatation of the gallbladder and steatosis. There were progressive alterations in the Golgi apparatus and accumulation of vesicles. The apical mucous droplets decreased in number and became pleomorphic and dispersed throughout the cytoplasm. Lipid droplets appeared in numbers on the epithelial cytoplasm. By 48 h the tissues had reverted to normal appearances. When cholecystokinin, pilocarpine or ceruletide were given to animals which had received colchicine 18 h previously, the excess bile from the dilated gallbladder was discharged into the duodenum, remaining apical mucous droplets secreted and electron dense material accumulated in the lateral intercellular space. This formed a quasi-regular array between the epithelial bases and the basement membrane. Biochemically there was a significant decrease in alkaline phosphatase activity and a significant increase in acid phosphatase activity.

Acid Phosphatase↗
PubMedDate not supplied

Evaluation of Syva's enzyme immunoassay for the detection of Chlamydia trachomatis in urogenital specimens.

A newly developed microwell enzyme immunosorbent assay (EIA) system by Syva Company (Palo Alto, CA) can detect Chlamydia trachomatis in < 3 hr. It uses a polyclonal antibody to chlamydial lipopolysaccharide and end points are determined with a spectrophotometer. Three clinical trial sites (University of California Medical Center, San Francisco, CA; University of Washington, Seattle, WA; and Louisiana State University Medical Center, New Orleans, LA), compared this EIA with tissue culture (TC) for identifying Chlamydia in urogenital specimens. Overall prevalence by TC was 10.4% (136 of 1306). When tests were compared with TC (using vials or microtiter plates and a fluorescent antibody stain), we found an EIA sensitivity of 93.4% (127 of 136) and a specificity of 98.1% (1148 of 1170). This EIA has a performance profile that is, at the very least, comparable with other nonculture methods for diagnosing genital tract infections with C. trachomatis.

Antibodies, Bacterial↗
PubMedDate not supplied

Process-outcome analysis in computer-aided treatment of obsessive-compulsive disorder.

The study purpose was to examine dose-response relationships between behavior on a computer-delivered treatment program and outcome in obsessive-compulsive disorder (OCD), and to report the use of human-computer interactions (HCIs) as a process measure in psychotherapy research. Thirteen OCD patients completed three 45-minute sessions at weekly intervals on an interactive computer program which provided vicarious exposure and response prevention for OCD. The scenario modeled exposure to dirt for the treatment of a hand-washing ritual. HCIs were recorded and analyzed to provide a detailed description of the behavioral strategies used. The relationship between subject characteristics, process measures, and outcome was examined. Across the three computer treatment sessions, all subjects showed a marked increase in vicarious exposure behavior, that is, enacting a hand-dirtying behavior sequence on the interactive computer program. Some subjects enacted hand-washing, although this decreased across sessions. A higher amount of vicarious hand-dirtying behavior predicted symptom reduction on the Padua Inventory (PI). Higher National Adult Reading Test (NART) scores, an intelligence measure, predicted more enactments of hand-dirtying behavior, but the relationship between hand-dirtying and outcome remained significant after controlling for NART scores. We conclude that HCIs are a novel and objective process measure that may aid in clarifying specific treatment factors. The relationship between hand-dirtying and outcome suggests a likely increased benefit from higher treatment dosages.

Adult↗
PubMedDate not supplied

College women's attitudes and expectations concerning menstrual-related changes.

The present study examined college women's expectations, attitudes, and knowledge about menstrual-related changes in order to provide a more complete picture of how women perceive the experience of menstruation and to explore the interrelationships of these variables. The women responded to the Moos Menstrual Distress Questionnaire as if they were premenstrual and as if they were intermenstrual in order to examine expectations about symptom changes for themselves. They also responded to a series of agree/disagree items, which yielded five dimensions of attitudes or styles of coping with menstruation. In general, the results suggested that these college women accepted menstruation rather routinely and did not perceive it as overly disruptive. Furthermore, it appears that beliefs about menstruation are more complex than previously thought, involving differential perceptions of physical versus psychological symptoms and a variety of dimensions of menstrual-related attitudes.

Adaptation, Psychological↗
PubMedDate not supplied

Autoantibodies to islet amyloid polypeptide in diabetes.

Islet amyloid polypeptide (IAPP) is the constituent peptide of amyloid in pancreatic islets of Type 2 diabetic patients and in insulinomas. Amyloid formation in Type 2 diabetes is associated with islet cell destruction which may promote formation of autoantibodies to IAPP. An ELISA method has been developed to detect IAPP autoantibodies and used to assay serum from 80 non-diabetic subjects, 49 Type 1 and 228 Type 2 diabetic patients, and 10 patients with insulinomas. Microtitre plates coated with IAPP 1-37 were used to detect antibody binding followed by an alkaline phosphatase conjugated anti-human IgG. ELISA binding decreased with sample dilution and with pre-incubation of the samples with IAPP. The optical density of the substrate reaction was compared with results from a standard serum from a non-diabetic subject (OD ratio). Elevated OD ratios were detected in some subjects from each patient group but the Type 2 diabetic group had significantly higher titres than the non-diabetic subjects (p less than 0.001). The OD ratio was elevated (greater than mean + 2SD non-diabetic group) in 15% of Type 2 and 18% of Type 1 diabetic patients and in 20% with insulinomas. IAPP antibody levels did not correlate with age or gender of subjects, or duration of diabetes. IAPP autoantibodies could be an additional marker for B-cell damage in diabetes.

Adult↗
PubMedDate not supplied

An unusual cause of back pain in a young athlete. A case report.

Back pain in the young athlete is a common problem seen in many sport medicine clinics. Not only can this be a difficult problem for the physician to manage (due to inability to pinpoint the pathology), but it is a frustrating experience for the athlete, unable to compete or train effectively. The sport medicine physician must, therefore, always be alert and obsessed with obtaining a precise diagnosis to be followed by specific treatment. When presented with the adolescent athlete suffering with back pain, one must consider the full gamut of diagnostic possibilities. Mechanical or spondylogenic causes are most common; however, potentially more serious infective, metabolic, and neoplastic conditions should also be considered.

Adolescent↗
PubMedDate not supplied

Implementation of a multidisciplinary disease management program for heart failure patients.

Institutions across the country are considering the feasibility of a disease management program for heart failure (HF) patients. Published reports suggest that such programs can save money and improve outcomes. However, the design of a disease management program can be challenging. This paper describes the structure and function of a successful disease management program for heart failure patients. The program is supported by a multidisciplinary team of nurses, pharmacists, dietitians, social workers, and physicians who approach the problem from a self care perspective. Program components include standardized educational materials, reinforcement of educational contacts, monthly support groups, and a quarterly newsletter. Existing staff built the program with few additional resources and staff. The program, which costs only approximately $330/patient for a 6 month intervention, has decreased hospital readmissions (29%) and days in the hospital (43%) significantly. (c)1999 by CHF, Inc.

Journal Article↗