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Biomedical subjects

K Oka

Publications and source records attributed to K Oka.

At least 541 records · Page 30Linked to original sources

[Intracranial hemorrhage in autopsy cases with occlusion of the circle of Willis (author's transl)].

Seventeen autopsy cases with occlusion of the circle of Willis were examined clinicopathologically. These patients ranged in age from 8 years to 64 years and consisted of 6 males and 11 females. The following results were obtained. 1. Fresh and massive intracerebral hemorrhage was confirmed in 13 of 17 patients and cerebral infarct in 4 of 17 patients. 2. Among these 13 patients, massive hemorrhage was found in basal ganglia, thalamus and hypothalamus of 9 patients, and in thalamus, cerebral peduncle and midbrain of 4 patients. 3. Rupture of the dilated muscular-type arteries was noted in the thalamus and basal ganglia in 2 of 13 patients. Ruptured arteries with organization of the lumen were found in the old hemorrhagic foci in one of them. 4. Overgrown and dilated arteries, branching off from the circle of Willis, were confirmed in 11 patients. These arteries consisted of "perforating" arteries well developed as collateral circulation. 5. No ruture in these arteries of the subarachnoidal spaces was found in 11 patients. In one of them, a small saccular aneurysm was found. These findings strongly suggest that in patients with occlusion of the circle of Willis intracerebral rupture of overgrown "perforating" arteries as collateral circulation may be the main cause of intracranial hemorrhage and intracerebral hemorrhage due to rupture of the arteries may be repeated.

Adolescent↗

Serum and tissue lipids and glomerulonephritis in the spontaneously hypercholesterolemic (SHC) rat, with a note on the effects of gonadectomy.

A spontaneously hypercholesterolemic male rat, found in the Sprague-Dawley strain, was mated with normocholesterolemic females of the same strain: the male offspring were hypercholesterolemic. By selecting rats according to their plasma cholesterol levels and repeated brother-sister mating, progeny became progressively more hypercholesterolemic--especially the males--when fed a basal low-cholesterol diet. These rats were tentatively given the short name of SHC and have at present been bred to the F14 generation. Hypercholesterolemia in male SHC rats proceeded in two stages: plasma cholesterol rose only slightly during the first stage up to the age of about 10 weeks and then increased progressively in the subsequent stage. Female SHC rats developed a high degree of hypercholesterolemia from the age of 10 months. SHC rats maintained on the basal diet were not obese, but their kidneys and livers enlarged. Histological examination showed that glomerulonephritis developed in the kidney of male SHC rats by the age of 9 months. The liver of these rats was not fatty and contained rather less lipid than usually found in the normal Sprague-Dawley rat. Male and female SHC rats were subjected to gonadectomy at the age of 4 weeks, and were then maintained on the basal diet for 18 weeks. Blood cholesterol was higher throughout the experiment in ovariectomized female SHC rats than in controls, and the renal lesion was correspondingly worse. However, gonadectomy in male SHC rats had no effect on the disease.

Aging↗

Induction of aortic lipid deposition in a high-response (ExHC) rat fed a diet containing cholesterol and cholic acid.

Male ExHC and Sprague--Dawley rats were fed a diet containing 3% cholesterol, 0.6% sodium cholate and 15% olive oil for 16 weeks. The ExHC rat is highly susceptible to dietary hypercholesterolemia. Aortas of the ExHC rats showed Sudan-stained deposits and cholesterol accumulation in the intima and media, whereas no deposited lipids were seen in those of the Sprague--Dawley rats. In male and female ExHC rats fed diets containing the above supplements at 3 dose levels, plasma cholesterol and aortic lipid deposition were found to be dose-dependent. Lipid deposition was more prominent in female than in males, but aortic intimal proliferation was absent.

Animals↗

Ceroid-like histiocytic granuloma of gall-bladder --a previously undescribed lesion--.

In the present study, 13 cases of a peculiar gall-bladder granuloma characterized by marked proliferation of ceroid-filled brown histiocytes were pathomorphologically, histochemically and ultrastructurally examined to define the pathologic features of such a lesion previously undescribed in the literature. The lesion grossly showed a granulomatous appearance of yellow brown to dark brown color developing in the wall of gall-bladder. Histologically, there was proliferation of histiocytes containing abundant brown pigment granules in their cytoplasm. The pigment granules proved to have staining characteristics closely resembling those of lipogenic ceroid-like pigment. Ultrastructurally, these granules showed membrane-bound, pleomorphic osmiophilic inclusions of heterogenous materials. With regard to the pathogenesis of this granuloma, it may be suggested that lipid components of bile juice, particularly unsaturated fatty acids and phospholipids, play an important role as a source of ceroidogenesis in the proliferating histiocytes.

Adolescent↗

A case of juxtaglomerular cell tumor diagnosed preoperatively.

A case of juxtaglomerular cell tumor, the fourth case in the world diagnosed preoperatively, was reported. Neither strict sodium restriction nor loading of upright position increased a grade of hyperreninemia observed at recumbant position on ordinary diet, but Pald elevated in response to them. Abnormal glucose tolerance was considered to be due to hypopotassemia. Selective renal arteriography revealed a small number of tumor vessels, a lucent area on the nephrogram and early appearance of the renal vein of the diseased side. Histologically, the tumor contained some canalicular structures among the polygonal nonepithelial tumor cells with rhomboid bodies. These findings suggested that this tumor was a hamartoma originated from the juxtaglomerular apparatus.

Adolescent↗