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Biomedical subjects

T L Hall

Publications and source records attributed to T L Hall.

At least 37 records · Page 2Linked to original sources
PubMed1987

Prediction of cervical neoplasia diagnosis groups. Discriminant analysis on digitized cell images.

The purpose of this study was to develop discriminant analysis models for predicting cervical dysplasia/neoplasia case diagnoses using cytometric features derived from the digital image analysis of cell monolayers. The data base consisted of 925 cells from 27 cases diagnosed either as moderate dysplasia (n = 10), severe dysplasia (n = 5), carcinoma in situ (n = 8) or invasive carcinoma (n = 4) on both tissue biopsy and monolayer preparations. Cell features examined were cell diameter, nuclear diameter, nuclear mean optical density (OD), nuclear integrated OD (IOD), nuclear OD standard deviation, normalized IOD, nuclear texture and nuclear-cytoplasmic ratio. Features derived from cells visually classified as moderate dysplasia correctly predicted the case diagnosis of moderate dysplasia versus more severe disease for 85% of the cells. Prediction models using summary measures (mean and variance) derived from all visually classified abnormal cells within each case correctly separated all cases into their respective diagnostic categories. These findings suggest that dysplastic cells in a cytologic sample have features that collectively reflect the tissue diagnosis, regardless of the visual differences among the cells. Such information has potential use for diagnosis and possibly for prognosis.

Carcinoma in Situ↗
PubMed1986

Experience with renal transplantation in children undergoing peritoneal dialysis (CAPD/CCPD).

For children with end-stage renal disease, renal transplantation is the ultimate goal because it offers the potential of maximum rehabilitation. In order to evaluate the infectious risk of renal transplantation in patients previously maintained on continuous ambulatory peritoneal dialysis (CAPD) and/or continuous cycling peritoneal dialysis (CCPD), we retrospectively evalauted the clinical course of 44 pediatric patients (mean age 12.0 +/- 5.7 [SD] years) who received 32 cadaver and 16 live-related donor renal grafts after being maintained on peritoneal dialysis for 756 patient-months (mean 17.1 +/- 11.5 months). In the posttransplant period, 25 patients (57%) required dialysis because of acute tubular necrosis or acute rejection. Peritonitis developed in five patients (11%) following transplantation; two were being dialyzed at the time. Exit-site and tunnel infections occurred in nine patients (20%). In all instances, antibiotic treatment and/or catheter removal was curative. Posttransplant ascites developed in 12 patients (27%) and was alleviated by catheter drainage. The catheters were left in situ at the time of transplantation and electively removed when stable graft function was present. The 1- and 2-year actuarial graft survival rate was 65% and 55%, respectively. One patient died in the immediate posttransplant period, which was unrelated to peritoneal dialysis. In conclusion, pediatric patients maintained on CAPD and/or CCPD can be safely transplanted. The potential infectious risks related to peritoneal dialysis can be managed with appropriate management of the catheter and prompt antibiotic therapy. The patient and graft survival rates are comparable to those with patients receiving hemodialysis prior to transplantation. There is no need to limit access to transplantation in children undergoing CAPD and/or CCPD.

Adolescent↗
PubMed1986

Nuclear deoxyribonucleic acid heterogeneity of ovarian borderline malignant serous tumors.

Sixteen borderline malignant serous ovarian tumors and seven well-differentiated invasive serous ovarian carcinomas were examined with the technique of Feulgen microspectrophotometry for the determination of nuclear deoxyribonucleic acid (DNA) ploidy patterns (diploid versus aneuploid) and ploidy levels of the stem cell lines. Of the nine stage I-II borderline malignant tumors, only one (11%) was aneuploid. In contrast, four of seven (57%) stage III borderline malignant neoplasms and all stage III carcinomas were aneuploid. The stem cell modal values in all borderline serous tumors were less than triploid (3N) while in five of seven carcinomas stem cell modal values were greater than triploidy. This contrast in ploidy patterns and ploidy levels may explain the differences in biologic behavior between borderline malignant serous tumors and invasive serous carcinomas of the ovary.

Adult↗
PubMed1985

DNA ploidy measurements in tissue sections.

Nuclear DNA ploidy measurements based on tissue sections, although technically tedious and time consuming, can provide useful diagnostic and prognostic information. Methods for minimizing distributional errors and optimizing interpretation of DNA histograms are presented, and the diagnostic and prognostic significance of DNA ploidy measurements in gynecologic cancer and its precursors is reviewed.

Cell Nucleus↗
PubMed1984

Interspecialty variation in office-based care.

Analysis of national survey data on physician-patient encounters raises questions about physician education and manpower policy. Data compiled by the University of Southern California Medical Activities and Manpower Projects and the United States Bureau of Health Professionals reveal differences among internists, cardiologists, family practitioners, and pediatricians in procedures used for diagnosing and treating several frequently encountered conditions. Differences are observed in expenditure of time and use of a broad range of diagnostic and therapeutic techniques. These differences remain significant even after several important characteristics of individual physicians, patients, and the practice environment have been controlled. Findings from this study underscore the necessity of reviewing the content of medical education and policies that encourage a broad range of specialists to provide primary care. The findings also emphasize the need to address the physician's knowledge base in promoting changes in practice patterns.

Cardiology↗
PubMed1983

Predicting 2,4-dichlorophenoxyacetic Acid ester transformation rates in periphyton-dominated ecosystems.

Using batch cultures, we determined transformation rate coefficients for microbial transformation of 2,4-dichlorophenoxyacetic acid butoxyethyl ester (2,4-DBE) in periphyton-dominated ecosystems. Rates of 2,4-DBE loss were measured over short periods of time (usually less than 10 h), and first-order transformation rate coefficients (k(1)) were determined under the specific conditions of low 2,4-DBE concentrations and no growth. Values for k(1) were divided by total plate counts and by biomass measured as ash-free dry weight to give second-order rate coefficients (k(b) and k(AFDW), respectively) for use in predictive models. Using periphyton attached to Teflon strips, we also determined second-order rate coefficients based on the ratio of colonized surface area to container volume (k(A)). Mean second-order rate coefficients were used to predict 2,4-DBE transformation rates in microcosms having diverse chemical and biological environments. The observed transformation rates among the microcosms were most accurately predicted by using k(A).

Journal Article↗
PubMed1981

Effect of antacids on the bioavailability of diflunisal in the fasting and postprandial states.

Diflunisal is long-acting salicylate derivative. We examined the effect of single concomitant doses of three antacids on diflunisal bioavailability under fasting or fed conditions (30 min after finishing a standard meal). With the use of an open, randomized, and balanced design, one 250-mg diflunisal tablet was given to each of 12 healthy men under six conditions: fasted, no antacid; fed, no antacid; fasted, 15 ml of aluminum hydroxide gel; fed, 15 ml of aluminum hydroxide gel; fasted, 10 ml magnesium hydroxide suspension; and fed, 15 ml of an aluminum hydroxide/magnesium hydroxide mixture. Diflunisal plasma 0- to 48-hr area uiven to each of 12 healthy men under six conditions: fasted, no antacid; fed, no antacid; fasted, 15 ml of aluminum hydroxide gel; fed, 15 ml of aluminum hydroxide gel; fasted, 10 ml magnesium hydroxide suspension; and fed, 15 ml of an aluminum hydroxide/magnesium hydroxide mixture. Diflunisal plasma 0- to 48-hr area uiven to each of 12 healthy men under six conditions: fasted, no antacid; fed, no antacid; fasted, 15 ml of aluminum hydroxide gel; fed, 15 ml of aluminum hydroxide gel; fasted, 10 ml magnesium hydroxide suspension; and fed, 15 ml of an aluminum hydroxide/magnesium hydroxide mixture. Diflunisal plasma 0- to 48-hr area under the time curve (AUC), peak plasma concentrations, and 0-to 96-hr urinary excretion were determined. Food (alone) decreased peak plasma concentrations by 16% (P less than 0.05) but did not affect AUC or urinary excretion. Under fasting conditions, aluminum hydroxide reduced AUC by 26% (P less than 0.01), peak plasma concentrations by 46% (P less than 0.01), and urinary excretion by 14% (P less than 0.05). Magenisuum hydroxide suspension (in the fasting state) increased the early plasma concentrations (by 130% at 0.5 hr and 64% at 1 hr, P less than 0.05) and increased AUC by 10% (P less than 0.05) but had no effect on urinary excretion. In the fed state neither aluminum hydroxide nor the aluminum hydroxide/magnesium hydroxide mixture had any detectable effect.

Adult↗
PubMed1980

Training developing-world personnel in family planning and population: accomplishments and patterns.

The characteristics of more than 12,000 persons from developing countries who received training in population and family planning subjects during 1966-78 are reviewed. During these years many changes occurred with regard to trainee origin, professional background, nature and duration of training program attended, and other important characteristics. The observed patterns of trainee characteristics over time suggest the presence of defined stages of manpower training that are largely predictable. These trends suggest an empirical basis for anticipating future training needs and for evaluating training activities.

Adult↗
PubMed1979

Working life of health professionals.

A comparison was made between the indirect method of preparing a profession-specific working-life table and the direct method. The former uses data on the number of physicians per 1,000 population by age and assumes that the mortality rate for the profession is equal to that of the population as a whole. The latter method makes use of information on profession-specific mortality and on active and inactive status of living physicians. These two approaches were applied to physician data for the United States of America and it was noted that the direct method gives estimates of working life and total life expectancy that are significantly higher than by use of the indirect method. The likely magnitude and directions of the biases inherent in each of the methods are then discussed. A comparison is then made of the estimated working life for Colombian, French and US physicians using the indirect method.

Actuarial Analysis↗
PubMed1977

The unmet demand for health services: a vital component in planning.

Consideration of unmet need as well as effective demand for health services is desirable for planning but frequently ignored. This paper reports an analysis of the findings from a national health survey conducted in Chile to obtain information on both met and unmet demand. The joint analysis proved feasible and highly informative. Total felt need tended to be relatively constant among population groups in comparison with differences in actual services utilization. Moreover, exceptions to this general finding revealed patterns that should improve our insights for health planning.

Analysis of Variance↗
PubMed1977

The applicability of inescapable shock as a source of animal depression.

Male rats (N = 27) were given initial experience with escapable shock, equivalent amounts of inescapable shock, or no shock. Measures were then obtained in the ensuing 15 hours on food intake, water intake, number of cage crossings, and weight change for all groups. Following this, animals were tested on an escape task. Inescapably shocked animals showed significant decreases in food and water consumption in comparison to both nonshocked and escapably shocked control rats. Weight gains were significantly decreased by exposure to shock irrespective of the availability of a coping response. Consistency of these findings with proposals suggesting that exposure to inescapable shock leads to a state of animal depression (learned helplessness) is discussed and compared to alternative stress explanations.

Animals↗
PubMed1975

Measurement and projection of the demand for health care: the Chilean experience.

Projection of the probable demand for health services over time is one of the most important-and difficult-aspects of the health planning process. Not only must the planner contend with many variables external to the health sector, but also with the difficult to predict correlations between the supply of health, services and the resultant demand. This article briefly reviews some of the principal demand projection methods in use and then describes in detail the one adopted in the Chilean health manpower study. The demand portion of the study in Chile involved three main elements: 1) a sample survey which measured the met and unmet demand for medical, dental, and hospital services as a function of six population variables (age, sex, location, income, educational level, and medical insurance status); 2) a baseline demand projection which takes into account the probable effects of changes in these six variables over ten and 20 years on the utilization of services; and 3) an alternative projection which postulates the fulfillment of certain targets for the improvement of health care. The approach offers the planner a number of important analytical and programmatic advantages compared with other methods now available and are discussed along with their limitations.

Age Factors↗