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Biomedical subjects

M Lipkin

Publications and source records attributed to M Lipkin.

259 records · Page 15Linked to original sources
PubMedDate not supplied

Cell proliferation in rat colon measured with bromodeoxyuridine, proliferating cell nuclear antigen, and [3H]thymidine.

Epithelial cell proliferation was studied in the normal colonic mucosa of 5-week-old Sprague-Dawley rats, comparing [3H]thymidine incorporation (group 1) with two newer proliferation markers, bromodeoxyuridine (group 2) and proliferating cell nuclear antigen (group 3). Microautoradiography (group 1) or immunoperoxidase assays (groups 2 and 3) were carried out. Cells were counted for positive reaction and position along 50 colonic crypt columns/animal. No significant differences were found in number or distribution of labeled epithelial cells in proliferative compartments in crypt columns of normal colonic mucosa; labeled cells were mainly in the lower 60% of colonic crypts. Thus, in this model, bromodeoxyuridine and proliferating cell nuclear antigens were comparable to [3H]thymidine as reliable markers of proliferating epithelial cells in rat colon.

Animals↗
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Effects of vitamin/mineral supplementation on the proliferation of esophageal squamous epithelium in Linxian, China.

Abnormalities of epithelial proliferation have been proposed as an early step in gastrointestinal carcinogenesis. To determine whether micronutrient supplementation may reduce squamous epithelial proliferation in the esophagus, we evaluated proliferation in subjects participating in a randomized nutrition intervention trial in Linxian, China, where esophageal cancer rates are among the highest in the world. After 30 months of intervention involving daily supplementation with multiple vitamins and minerals, an endoscopic survey was performed and squamous biopsies from 512 subjects were labeled with tritiated thymidine and autoradiographed. Analysis showed no treatment effect on the overall amount of squamous epithelial proliferation measured by the total labeling index. However, a measure of the vertical distribution of labeled cells showed lower values with supplementation: a 14% reduction in all subjects (P = 0.29), and a 29% reduction in nonsmokers (P = 0.03). These results suggest a potential modest benefit for short-term intervention with multiple vitamins and minerals on squamous epithelial cell proliferation of the esophagus in this high-risk population.

Adult↗
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A randomized double-blind intervention study on the effect of calcium supplementation on esophageal precancerous lesions in a high-risk population in China.

To determine whether dietary calcium supplementation affects esophageal precancerous lesions, 200 subjects with esophageal lesions in a high-risk area for esophageal cancer in China (Huixian, Henan) were randomly divided into 2 groups (100 subjects/group). Subjects in one group received an oral supplementation of calcium carbonate tablets (1200 mg of calcium daily), and subjects in the other group received placebo pills for 11 months. At the entry and the end of the trial, esophagoscopy was performed, and 2 or 3 biopsy specimens were taken from the middle and lower thirds of the esophagus and from macroscopic lesions, if any, of each subject for histopathology and cell proliferation analysis with deoxythymidine labeling. In comparison to normal epithelium, increased proliferative compartment size was observed in epithelia with hyperplasia or dysplasia. After the intervention, the percentage of individuals with "normal epithelium," "basal cell hyperplasia," "basal cell hyperplasia II," and "basal cell hyperplasia III and dysplasia" were 44, 31, 13, and 11% in the calcium group and 35, 39, 17, and 6% in the placebo group, respectively. The labeling index was 0.046 in the calcium group and 0.044 in the placebo group. After the intervention, the labeling index in basal cell layers 1 to 5, the major zone of cell proliferation, fell 38% in the calcium group and 44% in the placebo group from before the intervention. Therefore, in this study, calcium supplementation was not shown to have beneficial effects in alleviating precancerous lesions and abnormal cell proliferation patterns.

Adult↗
PubMedDate not supplied

Communication patterns of primary care physicians.

OBJECTIVES: To use audiotape analysis to describe communication patterns in primary care, to relate these to ideal relationship types as described in the literature, and to explore the patterns' relationships with physician and patient characteristics and satisfaction. DESIGN: Description of routine communication in primary care based on audiotape analysis and patient and physician exit questionnaires. SETTING: A total of 11 ambulatory clinics and private practices. PARTICIPANTS: The participants were 127 physicians and 537 patients coping with ongoing problems related to disease. MAIN OUTCOMES MEASURES: Roter Interactional Analysis System (RIAS) and patient and physician exit satisfaction questionnaires. RESULTS: Cluster analysis revealed 5 distinct communication patterns: (1) "narrowly biomedical," characterized by closed-ended medical questions and biomedical talk occurring in 32% of visits; (2) "expanded biomedical," like the restricted pattern but with moderate levels of psychosocial discussion occurring in 33% of the visits; (3) "biopsychosocial," reflecting a balance of psychosocial and biomedical topics (20% of the visits); (4) "psychosocial," characterized by psychosocial exchange (8% of visits); and (5) "consumerist," characterized primarily by patient questions and physician information giving (8% of visits). Biomedically focused visits were used more often with more sick, older, and lower income patients by younger, male physicians. Physician satisfaction was lowest in the narrowly biomedical pattern and highest in the consumerist pattern, while patient satisfaction was highest in the psychosocial pattern. CONCLUSIONS: Primary care communication patterns range from narrowly biomedical to consumerist patterns and parallel the ideal forms of patient-physician relationships described in the literature.

Analysis of Variance↗