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Biomedical subjects

M Miyagami

Publications and source records attributed to M Miyagami.

47 records · Page 3Linked to original sources

[Ventricular enlargement in experimental occlusion of superior sagittal sinus--in reference to histopathological findings (author's transl)].

An experimental occlusion of superior sagittal sinus was made in dogs according to ligation with thread at the posterior third portion of the sinus. Ventricular enlargement and histological changes in the cerebrum were studied in various stage after occulusion of the sinus. In the acute stage, no ventricular enlargement occured. However, in the chronic stage, nine dogs out of 12 dogs showed enlargement of the ventricle. Hitological examination revealed peeled ependymal layer from subependymal tissue, edematous findings in the periventricular tissue, perivascular gliofibrosis, perivascular hemorrhage, exanguination of plasm, and venous stasis in the ventricular wall and cerebral cortex in convexity. Extracellular space in the subependymal tissue, and the space between pial and glial membrane were widened remarkably. Two factors were raised by authors as the pathogenesis for ventricular enlargement. One factor was the hydrodynamic disturbance of CSF according to the CSF malabsorption into the superior sagittal sinus through arachnoid villi. The other one was the disturbance of venous circulation due to occlusion of the sinus.

Animals↗

[Hydrodynamic of the C.S.E. under experimental occlusion of superior sagittal sinus (author's transl)].

It is recognized that absorption of C.S.F. occurs mainly at the superior sagittal sinus through arachnoid villi after study of the Retzius (1875) and Weed (1914). We are interested in C.S.F. circulation and pathway on the obstructed superior sagittal sinus. At the border of middle one third and posterior one third of the superior sagittal sinus was obstructed experimentally. 1. When evans blue 0.5 to 1.0 ml was injected into lateral ventricle or cisterna magna, the evans blue was recognized on basal surface in either normal and obstructed dog of the superior sagittal sinus. Evans blue stained the convexity of normal dog, however, did not stain the convexity in the dog of obstructed superior sagittal sinus contrally. This was caused by the disturbance of C.S.F. circulation toward superior sagittal sinus. On the intraventricular injection of evans blue, it infiltrated into parenchym from ventripcle due to C.S.F. circulatory disturbance. 2. Study of radioactivity in the peripheral blood after intracisternal or intraventricular injection of RISA 100 muCi revealed that the radioactivity in the blood lowered with day after obstruction of superior sagittal sinus comparing with normal dogs. 3. Macroautoradiography after intracisternal or intraventricular injection of P 2mCi showed lower RI activity at the convexity, but increased activity at the basal brain in the obstructed dogs of superior sagittal sinus. These results showed that C.S.F. in normal dog was absorbed through the brain surface, expecially the basal surface of brain, other than through the superior sagittal sinus. Absorption of C.S.F. through the convexity of brain was disturbed significantly in the obstructed dogs of superior sagittal sinus. C.S.F. absorption into peripheral blood decreased in chronic stage after occlusion of surperior sagittal sinus and it suggested that the absorptive function of C.S.F. through the basal surface of brain was restricted.

Absorption↗