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D Thompson

Publications and source records attributed to D Thompson.

At least 145 records · Page 8Linked to original sources
PubMed1997

Subtle changes in benign tissue adjacent to prostate neoplasia detected with a Bayesian belief network.

The aim of this paper was to test the usefulness of a Bayesian belief network (BBN) as a decision support system in the uncertainty assessment of benign prostatic tissue, either associated or not with inflammation or adjacent to prostatic adenocarcinoma (PAC) or prostatic intraepithelial neoplasia (PIN). A shallow network was used with eight first-level descendant nodes for the diagnostic clues, each independently linked by a conditional probability matrix to a root node containing the diagnostic alternatives. One diagnostic evidence node was based on the tissue architecture and the others were based on cell features. The efficacy of the network was tested on a series of 45 simple prostatectomy specimens, subdivided as follows; benign prostatic tissue not associated with other diseases (15 cases), associated with acute and/or chronic inflammation (15 cases), and adjacent to accidentally discovered PAC or PIN (15 cases). The highest belief values for the diagnostic alternative normal prostate (NP) were obtained in the 15 cases not associated with other diseases, the mean value being 0.996. The 15 cases evaluated in areas with inflammation showed the lowest belief values for NP (mean 0.774). For the 15 cases evaluated in specimens with PAC or PIN, the belief values for NP were intermediate between those from normal prostatic tissue associated with inflammation and those not associated (mean 0.925). Moreover, it was found that subtle changes were also present at a certain distance from the tumour. In conclusion, the network can be used as a decision support system to differentiate with high certainty benign prostate adjacent to PAC or PIN from benign prostatic tissue either associated or not with inflammation. The subtle morphological alteration detected with the BBN may be considered malignancy-associated changes.

Adenocarcinoma↗
PubMed1997

Specific Contributions of Politics, Economics, and Toxicology in Setting Socially Consensual Limit Values

/ Limit values are legal limits for the concentrations of substances in the environment. They must be agreed upon in a consensual procedure between science, economics/technology, and political forces. This is a crucial political precondition for their social acceptance. The arguments put forward to justify their expediency and numerical level are based not only on risk-benefit considerations but also on the aspect of the technical avoidability of direct and indirect exposure. The critical assessment of the direct benefit of specified exposures falls within the responsibility of economics/technology, whereas criteria for their potential adverse effects (direct and indirect) are provided by medicine/biochemistry and/or ecology. Within this concept, the avoidance of nonbeneficial-even if not openly adverse-exposure is the essential aim of environmental hygiene and should be promoted by politics/science. In general, society or segments thereof reject adverse, accept beneficial, and tolerate unavoidable exposure. Conflicts of interest arise when different groups of society simultaneously define a given exposure as being adverse, beneficial, and unavoidable. Therefore, from the viewpoint of society as a whole, an optimal exposure lies as far as reasonably achievable at a level lower than known or plausible adverse effect thresholds (as defined by toxicology or ecology). This optimal level of exposure must be determined using a transparent and, hence, public procedure.KEY WORDS: Legal limit values; Benefit threshold; Social acceptance; Social tolerability; Adverse effect threshold; Avoidable exposure; Tolerance threshold; Environmental hygiene

Journal Article↗
PubMed1997

Quantitative study of ductal breast cancer--patient targeted prognosis: an exploration of case base reasoning.

Current analytic methodologies allow the extraction, even from small tumor masses, of extensive information on the biologic characteristics of malignant lesions, such as tumor aggressivity, metastatic potential, drug resistance, and host interactions. Clinical practice now offers a wide range of therapeutic strategies. Information technological advances offer the opportunity to refer to very large data bases of patient anamnestic data, response to treatment and clinical outcome. There is a need to formulate therapy and prognosis for each individual case. Case based reasoning is a knowledge based methodology where the outcome for complex situations can be predicted by referring to a large data base of cases of known outcomes. The preliminary data obtained from this study suggest that case based reasoning may offer a promising approach to individual targeted prognosis.

Breast Neoplasms↗
PubMed1997

Scrotal pathology as the cause for hip pain. Diagnostic findings on bone scintigraphy.

Scrotal scintigraphy has become a relatively uncommon examination in many nuclear medicine departments. However, scrotal perfusion is visualized during three-phase bone imaging of the pelvis and hips. The authors present a compilation of three cases of hip pain secondary to unsuspected scrotal pathology documented on routine three-phase bone scintigraphy, discussing this topic for the first time in the literature. A short review of the pathophysiology of referred hip pain, differential diagnosis, and imaging alternatives emphasize the unique contribution of nuclear imaging.

Adolescent↗
PubMed1997

Value-adding in the rural training stream: a release program for hospital-based rural training stream registrars.

This paper describes a release program developed in 1995 for year I hospital based GP registrars in the Rural Training Stream of the Royal Australian College of General Practitioners Training Program in South Australia. Background, objectives, content and organisation, and evaluation are described. The 1996 program that developed from this pilot is also described.

Australia↗
PubMed1997

The soluble interleukin-2 receptor predicts mortality in older hospitalized men.

BACKGROUND: There is an inverse relationship between the soluble interleukin-2 receptor (sIL-2R) and serum albumin, cholesterol, transferrin, prealbumin, and hemoglobin. Inasmuch as low serum albumin and cholesterol have been associated with excess mortality, we hypothesized that elevated sIL-2R would predict mortality in older adults. OBJECTIVE: To determine if elevated sIL-2R predicts mortality in patients on a geriatric rehabilitation unit. DESIGN: Prospective cohort. SETTING: University-affiliated VA medical center. PARTICIPANTS: Seventy-two male patients aged greater than 60 years admitted to a geriatric rehabilitation unit. Patients with severe hepatic or renal disease were excluded. MEASUREMENTS: We measured serum albumin, prealbumin, cholesterol, transferrin, hemoglobin, body mass index (BMI), C-reactive protein (CRP), and sIL-2R upon admission. Subjects were followed for 1 year. RESULTS: Low serum albumin, prealbumin, and hemoglobin and high sIL-2R and CRP predicted 1-year mortality on univariate analysis. When these predictors were included as covariates in a Cox regression model, only sIL-2R was a significant independent predictor of mortality (P = .043). Multiple linear regression with the above covariates revealed that only sIL-2R predicted time to death at (P = .003). CONCLUSIONS: High sIL-2R and CRP and low albumin, prealbumin, and hemoglobin predicted mortality using univariate analysis on a rehabilitation unit. However, with multivariate analysis, sIL-2R was the sole predictor of mortality.

Aged↗
PubMed1997

A descriptive analysis of children's playground injuries in the United States 1990-4.

OBJECTIVES: To review playground injury statistics over a five year period in order to develop an awareness of how and where children in the United States are being injured. METHODS: All data are based on the United States Consumer Product Safety Commission's National Electronic Injury Surveillance System (NEISS) for playground related injuries during 1990-4. The surveillance data includes injuries recorded in more than 90 hospital emergency departments located throughout the United States. RESULTS: Each year there are roughly 211,000 preschool or elementary school-children in the United States who receive emergency department care for injuries associated with playground equipment. On average, 17 of these cases result in death. 70% of all injuries occur on public playgrounds, with nearly one third classified as severe. Swings, climbers, and slides are the pieces of playground equipment associated with 88% of all NEISS reported injuries. Falls to the surface are responsible for 70%. CONCLUSIONS: NEISS playground injury statistics contribute to our understanding of playground injuries. By identifying where and how children are injured, suggestions can be made in an attempt to make playgrounds safer.

Adolescent↗
PubMed1997

Diagnostic distance of high grade prostatic intraepithelial neoplasia from normal prostate and adenocarcinoma.

OBJECTIVE: To develop a distance measure based methodology to support the morphological evaluation of high grade prostatic intraepithelial neoplasia (PIN), a direct precursor of prostate cancer. METHODS: Eight morphological and cellular features were analysed in 20 cases of high grade PIN found in radical prostatectomy specimens from patients with adenocarcinoma. The diagnostic distance was evaluated to measure the extent to which the feature outcomes of the individual high grade PIN cases differed from the expected outcome profile of normal prostate, low and high grade PIN, and cribriform and large acinar adenocarcinoma. The belief value for high grade PIN was evaluated with a Bayesian belief network (BBN). RESULTS: Complete separation existed between the cumulative absolute diagnostic distances of these 20 cases from the prototype feature outcomes of high grade PIN and normal prostate the values for which were < or = 3 (range 0 to 3) and > or = 9 (range 9 to 15), respectively. The distances from low grade PIN (range 3 to 9), cribriform adenocarcinoma (range 2 to 8), and large acinar adenocarcinoma (range 5 to 10) were intermediate and showed overlap in their distribution. When taking into consideration whether the severity of feature changes was increasing or decreasing in comparison with the category prototype outcomes, the cumulative directional diagnostic distances from high grade PIN ranged from -3 to +3. Positive distance values were seen relative to low grade PIN (range +3 to +9) and relative to normal prostate (range +9 to +15). Negative values were found relative to cribriform adenocarcinoma (range -8 to +2). The distance values from large acinar adenocarcinoma ranged from -2 to +4 and partly overlapped with those from the high grade PIN category. A bivariate scattergram derived from both diagnostic distance measures showed excellent separation between the groups' distances. BBN analysis confirmed the morphology based diagnosis. The distance evaluation resulted in 18 cases whose belief value for high grade PIN ranged from 0.60 to 0.87. In the remaining two cases the results of the BBN analysis showed a belief value of 0.50 and 0.57 for low grade PIN and of 0.49 and 0.38 for high grade PIN, respectively. CONCLUSIONS: Distance measure based methodology represents a useful diagnostic decision support tool for the accurate evaluation of high grade PIN.

Adenocarcinoma↗
PubMed1997

Computer-assisted discrimination of glioblastomas.

OBJECTIVE: To measure a number of nuclear features in a series of glioblastomas and compare the data with those from a set of anaplastic and low grade astrocytomas. STUDY DESIGN: The material consisted of toluidine blue-stained smears from 13 consecutive cases of glioblastoma. Smears from 12 high grade astrocytomas and 13 low grade fibrillary astrocytomas were used for comparison. Fifty nuclei were measured in each case. Cell images were segmented by an interactive procedure. A set of features representing both morphometric and nuclear texture characteristics was computed. RESULTS: The use of a discriminant function based on two features related to the gray value distribution resulted in the separation of all low grade astrocytomas from glioblastomas. When the corresponding discriminant function was computed for high grade astrocytomas and the values were plotted against optical density, the glioblastomas formed a group at a greater distance from the low grade astrocytomas than from the high grade astrocytomas. A second discriminant function based on two features allowed complete separation of the glioblastoma cases from the high grade astrocytomas. CONCLUSION: In our material, chromatin texture analysis allowed effective separation of astrocytic tumors with different histologic grades of malignancy.

Astrocytoma↗
PubMed1997

Computer-assisted analysis of medulloblastoma. A cytologic study.

OBJECTIVE: To explore data from a set of cases of medulloblastoma to see whether quantitative image analysis might suggest evidence for the existence of lower and higher grade lesions. STUDY DESIGN: Fourteen consecutive cases of medulloblastoma were obtained. Smears were stained with toluidine blue. For each case, 50 nuclei were measured and a number of densitometric features extracted. RESULTS: The existence of two subgroups of cases, identified as lower and higher grade groups, was suggested by a plot of the total optical density versus nuclear area. Two nuclear texture features--the number of pixels with the same optical density value occurring consecutively in the nucleus and the proportion of pixels in the high optical density range--divided the cases into the same subgroups. The use of a clustering algorithm established two clusters that corresponded to that subgrouping except for one case. Discriminant analysis gave an identical classification, with the misplaced case having a borderline discriminant function score. An unsupervised learning algorithm based on an adaptive distance metric formed two clusters and assigned the borderline case to the low grade subgroup. The grouping obtained by quantitative analysis was only partly related to the grade of nuclear atypia subjectively evaluated. CONCLUSION: In our series of medulloblastomas, quantitative analysis provided a means of detecting differences in the nuclear size and texture that allowed the classification of cases into two subgroups.

Adult↗
PubMed1996

The regulatory role for magnesium in glycolytic flux of the human erythrocyte.

31P NMR was used to measure the intracellular free magnesium concentration ([Mg2+]i) in human erythrocytes while [Mg2+]i was changed between 0.01 and 1.2 mM using the divalent cationophore A23187. 13C NMR and [2-13C]glucose were used to determine the kinetic effects of [Mg2+]i by measuring the flux through several parts of the glucose pathway. Glucose utilization was strongly dependent on [Mg2+]i, with half-maximal flux occurring at 0.03 mM. The rate-limiting step was most likely at phosphofructokinase, which has a Km(Mg2+) of 0.025 mM in the purified enzyme. Phosphorylated glycolytic intermediate concentration was also strongly dependent on [Mg2+]i and [MgATP], and glucose transport plus hexokinase may have been partially rate-determining at [Mg2+]i below approximately 0.1 mM. The pentose phosphate shunt activity was too low to determine the dependence on [Mg2+]i. Phosphoglycerate kinase and 2, 3-diphosphoglycerate mutase fluxes were also measured, but were not rate-limiting for glycolysis and showed no Mg2+ dependence. Human erythrocyte [Mg2+]i varies between 0.2 mM (oxygenated) and 0.6 mM (deoxygenated), well above the measured [Mg2+]i(1/2). It is unlikely, then, that [Mg2+]i plays a regulatory role in normal erythrocyte glycolysis.

Bisphosphoglycerate Mutase↗
PubMed1996

Collaborating on the integration of cancer nursing services.

This article outlines the proposals contained in the Calman-Hine report (DoH 1995), and then presents the work of a nursing task group set up in response to its recommendations. The authors describe how different agencies collaborated in a network approach to improving the provision of cancer services.

Breast Neoplasms↗
PubMed1996

Use of terfenadine and contraindicated drugs.

OBJECTIVE: To assess changes in concurrent use of products containing terfenadine and contraindicated macrolide antibiotics (erythromycin, clarithromycin, troleandomycin) and imidazole antifungals (ketoconazole, itraconazole) following reports of serious drug-drug interactions and changes in product labeling. DESIGN: Retrospective review of computerized pharmacy claims. SETTING: A large health insurer in New England. PATIENTS: Health plan members with 1 or more paid pharmacy claims for products containing terfenadine between January 1990 and June 1994. MAIN OUTCOME MEASURES: Among persons with paid claims for terfenadine in any given month, percentage with a prescription for any contraindicated drug that alternatively was dispensed on the same day as ("same-day dispensing") or had therapy days that overlapped those of ("overlapping use") a prescription for terfenadine. RESULTS: Concurrent use of terfenadine and contraindicated drugs declined over the study period. The rate of same-day dispensing declined by 84% from an average of 2.5 per 100 persons receiving terfenadine in 1990 to 0.4 per 100 persons during the first 6 months of 1994, while the rate of overlapping use declined by 57% (from 5.4 to 2.3 per 100 persons). Most cases involved erythromycin. CONCLUSIONS: Despite substantial declines following reports of serious drug-drug interactions and changes in product labeling, concurrent use of terfenadine and contraindicated macrolide antibiotics and imidazole antifungals continues to occur.

Anti-Bacterial Agents↗
PubMed1996

Illegal poisoning.

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Animal Welfare↗