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Biomedical subjects

M K Yee

Publications and source records attributed to M K Yee.

5 recordsLinked to original sources

Gastric emptying and small bowel transit in male volunteers after i.m. ketorolac and morphine.

Ten male volunteers were studied in a randomized, double-blind crossover trial. Each received ketorolac tromethamine 30 mg and morphine sulphate 10 mg i.m. at an interval of 2 weeks. After a standard radiolabelled meal, gastric emptying half-time (GE) and small intestinal transit time (SIT) were measured using a gamma camera. Small intestinal transit time was measured also from end-tidal breath hydrogen (ETH), and overall gastrointestinal motility by time to first flatus (TFF). Mean GE, SIT and TFF were significantly prolonged by morphine compared with ketorolac (P less than 0.03); ETH was prolonged also, but the difference was not significant. There were no significant correlations between SIT, ETH and TFF. Most subjects reported adverse effects after morphine, but only one after ketorolac.

Adult↗

APACHE II: preliminary report on 100 intensive care unit cases in University Hospital, Kuala Lumpur.

A good overall assessment of the severity of illnesses of patients admitted to a general intensive care unit (ICU) is not without problems. The APACHE (acute physiology and chronic health evaluation) prognostic scoring system enables us to stratify acutely ill patients and compare efficiency of ICU therapy in different hospitals. This preliminary study carried out on 100 consecutive admissions to the ICU in University Hospital, Kuala Lumpur showed the spectrum of ICU admissions and the direct relationship between APACHE II score and mortality.

Acute Disease↗

Megakaryocyte morphogenesis stimulated in vitro by whole and partially fractionated thrombocytopenic plasma: a model system for the study of platelet formation.

Isolated guinea pig megakaryocytes were cultured in the presence of plasma from normal or thrombocytopenic rabbits. Thrombocytopenic but not normal plasma stimulated formation of long cytoplasmic processes and cytoplasmic fragmentation. Activity was found in the 60% to 80% ammonium sulfate fraction of thrombocytopenic plasma but not in the 0% to 60% fraction. The 60% to 80% fraction of normal plasma contained a small amount of activity. Both colchicine and vincristine inhibited the morphogenesis stimulated by thrombocytopenic plasma. Cytochalasin B and D both mimicked the thrombocytopenic plasma-induced morphological change and affected more megakaryocytes than did the thrombocytopenic plasma. Cytochalasin and thrombocytopenic plasma together had a synergistic effect, causing many megakaryocytes to form processes and break into cytoplasmic fragments 3 to 6 microns in diameter. Immunofluorescence staining with antitubulin antiserum showed that cytoplasmic processes formed in the presence of thrombocytopenic plasma contain microtubules and that fragments released by the megakaryocytes contain microtubule rings. A model for the cytoskeletal basis of platelet formation is proposed.

Animals↗

Differences in the X-ray sensitivity of cells in different regions of the sandwich, a diffusion-limited system for cell growth.

The sandwich system was recently developed as a tumor analog; like spheroids, sandwiches are diffusion-limited multicellular systems which exhibit a necrotic center and a viable cell border. Using sandwiches of the 9L cell line, we compared the X-ray sensitivity of cells in the inner half of the viable border, adjacent to the necrotic center, with that of cells in the outer half of the viable border, adjacent ot the medium. No cells were hypoxic at the time of irradiation. The cells in the inner half of the viable border exhibited an increased radioresistance over cells in the outer half. The effect was dose multiplying with a multiplying factor of 1.5. Besides the sandwich studies, the X-ray sensitivity of 9L plateau monolayer cultures (induced by starvation) was compared to exponentially growing monolayer cultures. The plateau cultures exhibited an increased radioresistance over the exponentially growing cultures. The effect was also dose multiplying with a multiplying factor of 1.5.

Animals↗