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Biomedical subjects

C K Yeh

Publications and source records attributed to C K Yeh.

43 records · Page 3Linked to original sources

Myocardial composition and function in diabetes. The effects of chronic insulin use.

This study was undertaken in an animal model of mild diabetes to determine if provision of chronic insulin replacement during postprandial hyperglycemia may modify the abnormalities of myocardium. Group 1 served as controls with normal glucose tolerance by intravenous testing. Two additional groups were made diabetic with low doses of alloxan. Diabetic animals of Group 2 were untreated (n = 6). Group 3 animals (n = 6) received regular insulin daily to reduce postprandial hyperglycemia. After one year with maintained body weight, the animals were studied in the intact anesthetized state using the indicator dilution technique for left ventricular volume determinations. Basal left ventricular function and contractility were similar to normals in both diabetic groups. During intraventricular infusion of saline, end-diastolic pressure rose to higher levels in untreated diabetes (14.8 +/- 2 mm Hg) than normals (8.8 +/- 0.84), despite similar basal levels. Insulin treatment was associated with higher filling pressures than in group 1 as well as reduced end-diastolic volume response. Collagen concentrations were enhanced an average of 50% in layers from the inner to outer myocardium in both untreated and treated diabetics, associated with sodium and water accumulation. Since hypertrophy was not present, the diminished compliance appeared related to increased collagen levels. On electron microscopy, the subcellular organelles of the cardiac cell appeared normal in both diabetic groups. Thus, collagen accumulation and abnormal myocardial function in this model of diabetes is not affected by control of postprandial hyperglycemia, but a potential role for sustained hormone replacement is not excluded.

Animals↗

Altered myocardial function and collagen in diabetic rhesus monkeys on atherogenic diet.

We have demonstrated that in rhesus monkeys, 18 months of diabetes alters the end-diastolic pressure, end-diastolic volume relations without hypertrophy. Accumulation of collagen in the myocardial interstitium was the apparent basis for abnormal left ventricular performance. Neither collagen concentration nor left ventricular performance were signigicantly affected by dietary lipid composition. These myocardial abnormalities occurred at a stage when coronary atherosclerosis was limited. However, the relative influence of coronary atherosclerosis and myocardial alterations during more prolonged lipid feeding remains to be determined.

Animals↗

Nonuniform biosynthesis of multiple hemoglobins in the adult rat and guinea pig.

Separation of adult rat bone marrow cells by the method of thin layer countercurrent distribution permits the analyses of 59Fe-tagged erythroid cells for the various multiple hemoglobins and the assignment of such hemoglobins to erythroid cells at different stages of their development. Of the six adult red cell hemoglobins, hemoglobin 5 is synthesized most actively in the earliest erythroid cell whereas hemoglobin 4 (the major hemoglobin of the red cell) is synthesized most actively in the latest erythroid cells, e.g. the reticulocyte. Experimental evidence also indicates that maturation of the erythroid cell is accompanied by a decreased rate of synthesis of hemoglobin 5. The earliest erythroid cells of the marrow contain two hemoglobins, 7 and 8, which are absent in the adult red cell. Similar studies with the guinea pig confirm the nonuniform biosynthesis of its two hemoglobins and suggest that the phenomenon may be a general one among mammalian multiple hemoglobins.

Amino Acid Sequence↗

Spinal bone density and tooth loss in a cohort of postmenopausal women.

Osteoporosis has been suggested to contribute to the edentulous condition. However, studies specifically designed to examine the relationship between tooth loss and osteoporosis are scarce, and reported results have been mixed. This study investigated the correlation between tooth loss and spinal bone density in a nonHispanic white female population. Forty-four subjects were recruited and divided into high and low spinal bone density groups based on whether the bone density was higher or lower than the age-adjusted population mean bone density. Missing teeth and periodontal status in these groups were assessed and analyzed. Tooth loss was not significantly different between subjects with low spinal bone density (4.90 +/- 0.89 teeth) and high spinal bone density (3.81 +/- 0.90 teeth). Tooth loss did not differ after age and periodontal adjustment. However, the loss of attachment levels (relative to the cementoenamel junction) was greater in the low spinal bone density subjects (3.42 +/- 0.30 mm) than in the high spinal bone density subjects (2.37 +/- 0.26 mm) (P < .05). The difference may have resulted from gingival recession (P < .05), because the gingival pocket depths were not significantly different between the two groups. In this study, total tooth loss was not directly associated with systemic bone density. However, periodontal disease was negatively associated with spinal bone density. Whether periodontal disease will ultimately lead to greater tooth loss in low spinal bone density group merits further investigation.

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