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Biomedical subjects

M R Dunn

Publications and source records attributed to M R Dunn.

15 recordsLinked to original sources

The shifting sands of graduate medical education.

Each year the American Medical Association (AMA) surveys all programs in graduate medical education (GME) accredited by the Accreditation Council for Graduate Medical Education. Because of the importance of GME in the national workforce policy debate, this year's survey report has been expanded to provide more detailed GME data. The authors describe the historical basis of the current GME workforce dilemma and the multiple forces that now tend to neutralize efforts to adapt to a changing marketplace. For example, as resident physicians find it increasingly difficult to locate suitable employment, one would expect a reduction in hospital-based programs and in the number of their resident physician appointments. Yet, while US medical graduates (USMGs) did not pursue certain programs in this year's National Resident Matching Program, AMA data show that during the past 2 years the reduced number of residents in hospital-based programs was almost exactly offset by the increased number in new and expanded programs. Also, more USMGs are leaving residency training to enter practice after 3 years of basic training in primary care (internal medicine, pediatrics, and family practice). At the same time, an increasing number of international medical graduates are remaining in subspecialty programs. Other examples are cited to show the ebb and flow of GME activities that behave like "shifting sands."

Education, Medical, Graduate

Effect of blood flow reversal in liver autotransplants upon the site of hepatocyte regeneration.

We studied the role of the direction of intrahepatic blood flow upon the location of hepatocyte formation in regenerating liver. Single liver lobes in the dog were autotransplanted to the region of the neck with the blood supply reestablished in a manner to perfuse the hepatic lobule from portal tract to central vein or, in a reverse direction, from central vein to portal tract. Partial resection of the nontransplanted liver was later performed to induce regeneration in the grafts by humoral means. Tritiated thymidine was administered, and radioautographs were prepared from excised graft and nontransplanted liver. In the "straight" blood flow grafts, as well as in all nontransplanted livers, labeled hepatocytes indicating DNA synthesis were found predominantly in the vicinity of the portal tracts. In the "reverse" blood flow grafts, labeled hepatocytes were more prevalent about the central veins. Thus, the localization of hepatocyte formation in the lobule during active liver regeneration cannot be attributed to an inherently greater capacity of periportal liver cells to divide but is probably related to their preferential exposure to blood constituent changes (humoral mechanisms). Hepatocyte regeneration in the presence of abnormal directional circulation might lead to lobular disorganization resulting in consequent biochemical aberrations despite the formation of new cells.

Animals