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Biomedical subjects

S Miki

Publications and source records attributed to S Miki.

At least 253 records · Page 14Linked to original sources

Interaction of calcium and microtubules in the action of cyclic AMP on the toad urinary bladder.

Involvement of microtubules in the cellular action of vasopressin was studied by physiological and biochemical procedures. The inhibitory effect of 10(-4) M colchicine on the hydro-osmotic response of the toad bladder to 2 mM cyclic AMP was completely blocked by an increase in the concentration of calcium in the serosal bathing medium from 1 to 8 mM. Most of the colchicine-binding activity of extracts of the bladder epithelial cells was recovered by DEAE-Sephadex chromatography in a procedure similar to that used to isolate tubulin of bovine brain. Sodium dodecyl sulfate urea and urea gel electrophoresis of the DEAE-Sephadex fraction from the bladder epithelial cells yielded bands that corresponded to those of bovine brain tubulin. When 8 mM CaCl2 was present in an incubation mixture, the binding of colchicine to tubulin from the bladder epithelial cells and bovine brain was significantly inhibited. However, 1 mM CaCl2 did not affect the binding of colchicine to tubulin. Although the present study supports the concept that microtubules and calcium play an important role in the cellular action of vasopressin on the toad urinary bladder, the mechanism by which calcium blocks the inhibitory effect of colchicine on the hydro-osmotic response to cyclic AMP could not be elucidated.

Animals↗

Simultaneous surgical treatment of tetralogy of Fallot and coronary artery aneurysm due to mucocutaneous lymph node syndrome in a 4-year-old child.

The simultaneous correction of tetralogy of Fallot and an aneurysm of the coronary artery due to mucocutaneous lymph node syndrome (MCLS) in a 4-year-old boy was successfully performed. Of the four aneurysms found on the coronary angiogram at the age of six months, the smaller three regressed spontaneously leaving slight dilatation and thickening of the arterial wall during the 4-year follow-up period. However, the largest one in the right coronary artery, which remained almost the same size, showed marked stagnation of blood in the aneurysm with the possibility of thrombosis and resultant myocardial infarction. At operation, there was a large aneurysm in the right coronary artery, 9 mm in width and 18 mm in length. The wall of the aneurysm was very thick and tightly adherent to the myocardium. The aneurysm was resected and an aorto-coronary bypass graft was fashioned from a saphenous vein taken from the patient's mother, since an autogenous vein was not available. A ventricular septal defect was closed and pulmonary stenosis was relieved without any difficulty. Postoperative cardiac catheterization and coronary angiography four weeks after the operation revealed satisfactory correction of the tetralogy of Fallot and a patent aorto-coronary vein graft. Several problems regarding surgical treatment of coronary artery aneurysm due to MCLS are discussed.

Adult↗