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Biomedical subjects

A Leaf

Publications and source records attributed to A Leaf.

At least 163 records · Page 9Linked to original sources

Medical education and practic in People's Republic of China.

A dramatic adaptation of medical education to meet indigenous needs and circumstances has occurred in the People's Republic of China in the context of a highly structured health care delivery and medical referral system, entailing a reduction in curriculum length from 6 to 3 years. Although general directions and guidelines are set centrally by Peking, considerable autonomy and flexibility exist in individual schools. The innovative approaches used include training medical students in countryside and factories as well as medical schools, combining traditional Chinese and modern Western medicine, opening hospital-run medical schools, and using unconventional methods of producing medical doctors. On graduation the students generally return to the communities from which they came. Although the total number of medical graduates still falls short of national requirements, the problem of maldistribution of physicians has been alleviated in China. Medical care is now readily available in rural areas, where 80% of the population resides.

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The role of cell swelling in ischemic renal damage and the protective effect of hypertonic solute.

The failure of blood flow to return to the kidney following a transient period of ischemia has long been recognized. The cause of this "no-reflow" has been investigated in the rat after a transient period of total obstruction of the renal arteries. The vascular pattern of the kidneys as visualized with silicone rubber injection shows a diffuse patchy ischemia throughout the kidney, which persists after release of the obstructed renal artery. Electron microscopic studies of ischemic kidneys showed that all cellular elements were swollen and limiting the available vascular space. Functional studies revealed an increase in plasma urea nitrogen and creatinine after 1 hr or longer ischemic periods. The ischemia, cell swelling, "no-reflow," and subsequent renal dysfunction occurring after obstruction to the renal arteries were corrected by the administration of hypertonic mannitol, but were unaffected by an equivalent expansion of the extracellular fluid volume either with isotonic saline or isotonic mannitol, showing that the osmotic effect was primary. The hypothesis is presented that ischemic swelling of cells may occlude small blood vessels so that recirculation does not resume even after the initial cause of the ischemia is no longer present; solutes which do not penetrate cell membranes are able to shrink swollen cells, increase the available vascular space and thus permit reflow of blood to the ischemic organ.

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Improvement in myocardial function and coronary blood flow in ischemic myocardium after mannitol.

The purpose of this study was to evaluate the effect of hyperosmolality on the performance of, and the collateral blood flow to, ischemic myocardium. The myocardial response to mannitol, a hyperosmolar agent which remains extracellular, was evaluated in anesthetized dogs. Mannitol was infused into the aortic roots of 31 isovolumic hearts and of 15 dogs on right heart bypass, before and during ischemia. Myocardial ischemia was produced by temporary ligation of either the proximal or mid-left anterior descending coronary artery. Mannitol significantly improved the depressed ventricular function curves which occurred with left anterior descending coronary artery occlusion. Mannitol also significantly lessened the S-T segment elevation (epicardial electrocardiogram) occurring during myocardial ischemia in the isovolumic hearts and this reduction was associated with significant increases in total coronary blood flow (P < 0.005) and with increased collateral coronary blood flow to the ischemia area (P < 0.005).THUS, INCREASES IN SERUM OSMOLALITY PRODUCED BY MANNITOL RESULT IN THE FOLLOWING BENEFICIAL CHANGES DURING MYOCARDIAL ISCHEMIA: (a) improved myocardial function, (b) reduced S-T segment elevation, (c) increased total coronary blood flow, and (d) increased collateral coronary blood flow.

Animals↗