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Biomedical subjects

W Bradford

Publications and source records attributed to W Bradford.

6 recordsLinked to original sources
PubMed2001

Duke's 3rd year: a 35-year retrospective.

PURPOSE: Our purpose was to review and evaluate Duke University School of Medicine's 3rd year. SUMMARY: Duke University School of Medicine instituted a dramatic change in its curriculum 35 years ago by restructuring the 1st, 2nd, and 4th years of medical school so that the entire 3rd year could be devoted to an elective research experience or independent study of the basic sciences. Today this "new curriculum" permits students to work in basic science laboratories or with clinical investigators, work toward a 2nd degree, and participate in basic science courses beyond the core curriculum. Students were surveyed in 1996 and 1998 about their 3rd-year experience. Results showed that 67% and 73%, respectively, believed the 3rd year was very helpful in facilitating their understanding and appreciation of biomedical and clinical research. Students especially valued the experience and availability of their preceptors and the range of opportunities available during the 3rd year. The most frequent critiques by students were the lack of opportunities to pursue clinical interests, difficulty integrating the 3rd year into the remainder of the curriculum, and a tendency to place too much emphasis on coupling the 3rd-year experience with scholarships and residency plans rather than on a specific investigative interest. CONCLUSIONS: Overall, both faculty and students value the 3rd year as a unique positive experience. Duke faculty have noted, however, that no other medical schools have attempted to replicate the Duke experience.

Curriculum↗
PubMed2000

Cytogenetics and mechanisms of spontaneous abortions: increased apoptosis and decreased cell proliferation in chromosomally abnormal villi.

Genetic defects of the zygote, such as chromosome aberrations, are the most frequent causes of abnormal embryonic development and spontaneous abortion. However, the underlying mechanisms remain unknown. Chromosome aberrations likely cause changes in placental morphology and function (such as size, shape, vascularity, and the presence of trophoblastic inclusion). We postulated that chromosome aberrations may affect rates of cell proliferation or programmed cell death (apoptosis) during the differentiation of chorionic villi. To address these questions, we evaluated cell proliferation using a monoclonal antibody to Ki-67 (a cell-cycle marker) and apoptosis using the in situ end-labeling method (TUNEL) on paraffin-embedded placental tissues. Tissues were obtained from spontaneous abortions in early gestational periods with normal (11 cases) and abnormal karyotypes (15 cases), as well as eight normal control placentas from elective abortions. Apoptotic cells were found in the stroma of all cases, but were significantly higher in number in the stroma of chromosomally abnormal versus chromosomally normal spontaneous abortions. The apoptotic index of the trophoblasts was not significantly different between groups. Cell proliferation was higher in muscularized blood vessels in chromosomally normal placentas (both elective and spontaneous abortions) versus chromosomally abnormal spontaneous abortions. Cell proliferation was different in the trophoblast and stroma between the groups but to a lesser degree than in blood vessels. The morphological and biological data presented here suggest that: (1) chromosomally abnormal spontaneous abortions may occur because of different mechanisms than chromosomally normal spontaneous abortions, (2) apoptosis of the stromal cells and cell proliferation in blood vessels and stroma play an important role in the differentiation and functioning of villi, and (3) these changes could explain the etiology of spontaneous abortion and growth retardation of chromosomally abnormal embryos.

Abortion, Induced↗
PubMedDate not supplied

Hepatic parenchymal cells in cystic fibrosis: ultrastructural evidence for abnormal intracellular transport.

Few ultrastructural observations of hepatic parenchymal cells in cystic fibrosis (CF) have appeared in the literature. Utilizing a unique opportunity to examine freshly fixed hepatic tissue by transmission electron microscopy, we studied 12 patients dying with CF at Duke Hospital from 1979 to 1981 in order to identify possible abnormalities of intracellular architecture. The major findings include (1) intracellular fatty vacuoles, (2) distended bile ductules and bile ducts containing increased cellular debris, (3) profiles of distended rough endoplasmic reticulum containing material of medium electron density, and (4) membrane-bound deposits of electron-lucent material containing electron-dense cores resembling mucus. We suggest that the material seen within the cytocavitary network reflects a derangement of intracellular transport.

Adolescent↗