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Biomedical subjects

S Shimokawa

Publications and source records attributed to S Shimokawa.

At least 163 records · Page 9Linked to original sources
PubMed1986

[Acute and chronic experimental tricuspid valvular stenosis in dogs].

Acute and chronic experimental tricuspid valve stenosis was produced in 20 dogs. Clinical and hemodynamic alterations that resulted from severe anatomic tricuspid valve narrowing were surprisingly mild. In the acute stenosis studies, the normal tricuspid valve area of 8.2 +/- 0.3 sq cm was narrowed to less than 1.0 +/- 0.1 sq cm with a resulting right auricle-right ventricle diastolic gradient of 3.7 +/- 0.7 mm Hg. In chronic studies, a decrease in tricuspid valve area from 7.6 sq cm to 1.6 +/- 0.3 sq cm produced a diastolic gradient of 1.8 +/- 0.2 mm Hg. After 60 days, overt signs of right-sided failure (pleural effusions and ascites) were absent, and histological evidence of passive congestion (liver and spleen) was not recognized. The splanchnic vascular beds appear to act as excellent buffers against increases in right-sided cardiac pressure. We conclude that isolated narrowing of the tricuspid valve must be very severe to cause notable clinical and hemodynamic changes.

Animals↗
PubMed1985

[A comparative study of experimental models for cardiac preservation through orthotopic transplantation].

Various kinds of models for canine heart preservation were evaluated through orthotopic transplantation. Following warm ischemic (WIT) and preservation times (PT), donor hearts were orthotopically transplanted to recipients and observed for 2 hours. The study was divided into four groups. A heart-lung preparation (Group A) was preserved by coronary perfusion with diluted blood for an hour following 15-minute WIT in A-1 (n = 33), and 2 hours following 30-minute WIT in A-2 (n = 19). Following 30-minute WIT, the heart (Group B) was preserved for an hour by coronary perfusion with diluted blood in B-1 (n = 20), a modified Krebs solution in B-2 (n = 14), and a EL-solution in B-2 (n = 14). Following 30-minute WIT, the heart (Group C) was preserved for 2 hours by a Langendorff's model with coronary perfusion using perfluorochemical in C-1 (n = 5) and Hydroxyethyl starch in C-2 (n = 1). In Group D, electromechanical arrest of the heart and coronary vascular washout were performed in D-1 (n = 8) with K+ cardioplegia, D-2 (n = 8) with K+-verapamil cardioplegia, and D-3 (n = 5) with Collins M-verapamil cardioplegia. The heart was then removed and suspended in the same solution. The graft was preserved at 4 degrees C for 6 hours in D-1 and D-2, and 24 hours in D-3. Fourty-eight % in A-1 and 26% in A-2 were successfully transplanted.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Adenoid cystic carcinoma of lacrimal gland.

Adenoid cystic carcinoma of the lacrimal gland is a relatively rare disease. Only two cases, a man of 61 and a woman of 54 were seen in our clinic from 1962-1981. They presented histopathology of the cribriform pattern characteristic of adenoid cystic carcinoma. The lesion in the male patient belonged to the solid type and was mainly composed of solid nests. It is emphasized that radiotherapy in addition to surgical excision of the tumor is recommended because of its infiltrative nature.

Carcinoma, Adenoid Cystic↗
PubMed1976

Nuclear magnetic relaxation studies of cytidine and its complexing dimethyl sulfoxide solution.

13C spin-lattice relazation times (T1 values) in cytidine were determined experimentally to investigate molecular motions of both metal-free and ion-complexed cytidines in dimethylsulfoxide solutions. It was found that the correlation times of the protonated carbons were equal within experimental error, and this equality of correlation times of different sites of the molecule suggests strongly isotropic random motion of the molecule. Correlation times for internal motion of the amino group obtained from the observed T1 of the amino protons are 4.6 -10(-11) S, 2.0 - 10(-9) S and 1.1 - 10(-10) S for the metal-free cytidine and the cytidine complexed with either CaCl2 or ZnCl2, respectively. An experimental value of T1 of the H6 proton of the cytidine base agrees very well with the value estimated from a conformation determined by the nuclear "Overhauser" effect. Spin-lattice relaxation time measurements of the 7Li nucleus in the LiCl/cytidine system strongly suggested that the 7Li cation is directly coordinated with cytidine.

Binding Sites↗