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Biomedical subjects

O Shimada

Publications and source records attributed to O Shimada.

At least 37 records · Page 2Linked to original sources
PubMed1989

[A case of primary hypothalamic malignant lymphoma with diabetes insipidus].

A case of primary malignant lymphoma involving the hypothalamus is reported. A 31-year-old man was admitted with progressive disorientation. A computed tomography (CT) scan demonstrated a normodense, homogenously enhanced, and nodular shaped mass lesion involving the suprasellar region and extending to the third ventricle. In view of marked cerebral edema, dexamethasone was intravenously administered, at a dose of 4 mg/4 hr, and gradually tapered off. CT scans obtained 10 days after the admission revealed dramatic regression of the lesion, which corresponded with the clinical remission. However, on the 4th day after the discontinuance of corticosteroid, a CT scan demonstrated the recurrence of the mass lesion. Because of the rapid deterioration of consciousness and the progressive enlargement of the mass and dilatation of the ventricles, partial removal of tumor and ventricular drainage were carried out on the 24th day after admission. Dexamethasone was intravenously administered again at a dose of 4 mg/4 hr. A CT scan obtained five days after the operation showed complete disappearance of the lesion, and the patient had became almost alert. CT scans obtained on the 18th day and the 35th day after the operation showed complete disappearance of the mass. However, Magnetic Resonance Imaging revealed a localized area of abnormal signal intensity in the hypothalamus. Diabetes insipidus was continuously observed from the time of admission. A concomitant change of beta-2-microglobulin (beta-2-MG) and immunoglobulin (IgA, IgG, IgM) concentrations in serum and cerebrospinal fluid (CSF) with clinical profiles and CT findings were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[A case of primary intracranial malignant melanoma with characteristic magnetic resonance imaging].

The authors reported a rare case of primary malignant melanoma in the central nervous system and discussed the findings of MRI. A 60-year-old male was admitted for examinations to discover the cause of his generalized tonic convulsions. On admission, he had neither neurological deficits, nor were there any abnormalities revealed during physical examination. Ct scan disclosed a slightly high-density mass with perifocal edema in the right parietal cortex which enhanced markedly after injection of contrast material. This lesion was hypointense on T1 weighted image of MRI (GE: 1.5 Tesla) and a hyperintense band was observed on the surface of the tumor. On T2 weighted image, the tumor showed iso-hypointensity surrounded by an increased signal area compatible with edema. On August 31, 1988, a gross total removal of the tumor was performed. Microscopically, it was identified as a malignant melanoma. No melanoma was found in other parts of the body during careful examinations, especially in dermatologic and ophthalmologic examinations. Characteristic findings of the hyperintense band on T1 weighted image coincided well with the pathological findings of excessive melanin deposition on the surface of the tumor, and which resulted from the paramagnetic free-radicals in the melanin. MR image may be useful for differentiation of intracranial malignant melanomas from other mass lesions.

Brain Neoplasms↗
PubMed1989

[A pleomorphic lipoma of the palm--comparison to spindle cell lipoma].

A pleomorphic lipoma usually occurs in the neck, the shoulder, and/or on the backs of men over the age of 50. This tumor displays a mixture of fat cells, pleomorphic cells, floret cells, and bundles of mature collagen fiber. Herein we report on a pleomorphic lipoma that occurred on the palm of a 56-year-old woman. An immunohistochemical study, performed to compare the characteristics of a pleomorphic lipoma with those of a spindle cell lipoma, has suggested that the pleomorphic and floret cells of a pleomorphic lipoma are similar to the spindle cells of a spindle cell lipoma and not to fat cells. Our result seems to indicate that these two tumors are on the same spectrum and only the quantity of the pleomorphism keeps them distinct.

Diagnosis, Differential↗
PubMed1988

[A clinicopathological study of mediastinal tumors].

One hundred and fifty-eight cases of mediastinal tumors have been studied clinicopathologically, based on patients of Nagasaki University Hospital from 1961 to 1984. Of these tumors, 29.7% were thymic tumors, 23.4% neurogenic tumors, and 21.5% were germ cell tumors, the frequencies of which reflected the same tendency as other such reports in Japan. Thirty-three cases were malignant tumors. Among them, thymomas were the most common (48.5%) as Wada et al. have reported. Extrathoracic metastases have observed in 2 thymomas. Thymomas associated with myasthenia gravis were seen in 6 cases in which 5 patients are still alive.

Adolescent↗
PubMed1988

[A clinico-statistical study of testicular tumors--a reevaluation of 90 cases at the Nagasaki University Hospital and affiliated hospitals].

We have treated 90 cases of testicular tumors at our institutes from April, 1962 to March, 1986. Of 75 which were germ cell type tumors, 35 were a seminoma, for which the 5-year survival rate was 100% for patients in stage I, and 50% for those in stage III, respectively. Forty cases were non-seminomas, and all cases determined as being in stage I survived for 5 years, whereas 47.6% cases of those in stage III survived for 4.5 years. Thirty-six percent of those with a stage I germ cell tumor were treated with a orchiectomy alone, while other cases also combined radiotherapy and/or chemotherapy. Almost all cases of an advanced tumor received combined retroperitoneal lymph node resection, radiotherapy and/or chemotherapy. Patients with an advanced nonseminomatous tumor showed better a survival rate if they were given CDDP chemotherapy.

Dysgerminoma↗
PubMed1986

Protection against hepatic injury by a novel spiropiperidine derivative.

The evaluation of a novel hepatoprotective agent, Y-8845 (8(2-dimethylaminoethyl)-3-oxo-4-phenyl-1-thia-4,8-diazaspiro [4,5]decane dihydrochloride monohydrate), against carbon tetrachloride (CCl4)- and endotoxin-induced acute and chronic hepatic injury was carried out in rats. This compound, in a dose-dependent way, markedly reduced the increases in serum transaminase activities, the extent of liver cell necrosis, and the delay in indocyanine green (ICG) disappearance produced by a single toxic dosage of CCl4. This protective effect was observed even at doses of Y-8845 lower than 10 mg/kg po. It was also shown to protect the liver against injury induced by endotoxin. Furthermore, in the chronic liver injury induced by repeated administrations of CCl4 for 12 weeks, significant reductions of the increases in serum enzyme activities, liver fibrosis, and liver enlargement, and improvement in the ICG retention rate, were recognized in the Y-8845-treated groups at 10 mg/kg po or less. These findings indicate that this new agent has a remarkable protective effect, and possibly a therapeutic effect on liver injury.

Alanine Transaminase↗
PubMed1986

Hydroxyl radical scavenging action of tinoridine.

Radical scavenging action of tinoridine, a non-steroidal anti-inflammatory drug with a potent anti-peroxidative activity, was investigated. Tinoridine reduced a stable free radical, diphenyl-p-picryl-hydrazyl, in the molar ratio of about 1:2, indicating its free radical scavenging ability. Tinoridine inhibited the lipid peroxidation in rat liver microsomes induced by xanthine-xanthine oxidase system in the presence of ADP and Fe2+, in which hydroxyl radical (. OH) is formed. Tinoridine was demonstrated to be oxidized in the course of the lipid peroxidation by following the fluorescence derived from the oxidation product of tinoridine. It was also oxidized by the xanthine-xanthine oxidase system in the presence of Fe2+, but its oxidation was slow in the absence of Fe2+ and almost completely inhibited by catalase. Tinoridine was also oxidized by H2O2-Fe2+ system producing . OH (Fenton reaction), but it did not affect the reduction of cytochrome c caused by superoxide radical. These results indicate that tinoridine is able to scavenge . OH and the main active oxygen species responsible for the lipid peroxidation is . OH. The anti-peroxidative and . OH scavenging ability of tinoridine should contribute to its anti-inflammatory action.

Adenosine Diphosphate↗
PubMed1984

Immunohistochemical characterization of thyrotropin-releasing hormone-containing neurons in rat septum.

A sensitive and specific immunohistochemical technique has been used to reveal the distribution of thyrotropin-releasing hormone (TRH) in extrahypothalamic regions. Numerous cell bodies of the lateral septum were surrounded by profiles of dense, spotted TRH-containing axon terminals, suggesting the presence of synaptic contacts. The immunoreactive TRH was found to decrease markedly after electrolytic lesion of the medial preoptic area. The same lesions also lowered the septal content of TRH to 65%, as estimated by radioimmunoassay.

Animals↗
PubMed1983

Interrelationship between serum and fecal sterols.

Seven healthy volunteers and 3 hospitalized patients were given the same diet for 6 days. The mean intake of cholesterol was 359 mg/day. There was a large difference in the fecal amount of cholesterol and coprostanol among the subjects. The ratio of coprostanol/cholesterol ranged from 0.01 to 4.27. The subjects whose feces contained smaller amount of coprostanol excreted larger amounts of beta-sitosterol and crude fiber, suggesting that the various activities of intestinal flora were lower than the other subjects. The difference in the activity of intestinal flora to convert cholesterol into coprostanol was ascertained by incubating the feces anaerobically with egg yolk in vitro. It was also demonstrated that cholesterol was synthesized de novo and the amount corresponded to 0.1-0.6 g/day. The amounts of sterols in the feces of the other 17 hospitalized patients were also determined and there was an inverse relationship between the serum cholesterol and coprostanol/cholesterol ratio in the feces. These results suggested that the conversion of cholesterol into coprostanol by the intestinal flora might have an important role in the regulation of serum cholesterol level.

Adult↗
PubMed1982

Studies on regression of atherosclerosis--role of lipid containers.

The appearance of the aortic wall of rabbits fed a lanolin containing diet was examined by scanning (SEM) and transmission electron microscopy (TEM) in order to clarify the mechanism of removal of lipids deposited in the aorta. SEM study showed that circulating leukocytes penetrated into the arterial wall in the early phase of the experimental atherosclerosis. In some specimens, spherical bodies with a diameter of 10-30 mu were observed along the cleavage of the marginal folds between the endothelial cells. TEM demonstrated that these bodies contained many lipid particles, and numerous active microvilli were seen on the body surface. In the deeper subendothelial space, villi of each body interdigitated. From these results, it is postulated that the circulating leukocytes penetrate under the endothelium and take up the deposited lipids. Then, they return to the blood stream, containing lipid rich particles. The deposited lipids in the atherosclerotic lesion would be removed by this process. We named this phenomenon as "exo-tissuesis with lipid containers". While lipids are believed to be removed from the atherosclerotic lesion by HDL, lecithin cholesterol acyltransferase and others at the molecular level, we suggest that lipid containers play important roles in the regression and prevention of atherosclerosis on a major scale-cellular and tissue level.

Animals↗
PubMed1981

Cerebral protective effect and radical scavenging action.

The role of radical scavenging action in cerebral protective effect of drugs was investigated in vitro. Incubation of rat brain mitochondrial suspension with ascorbic acid and Fe2+ resulted in the formation of malondialdehyde and a decrease in the turbidity of the suspension, indicating that the mitochondria were peroxidatively disintegrated. Nizofenone at 10 micro M or more inhibited the peroxidative disintegration of mitochondria, and complete inhibition was observed at 100-200 micro M. The action of nizofenone was also ascertained by experiments with rat liver mitochondria. The anti-peroxidative activity of nizofenone was estimated to be approximately equivalent to that of alpha-tocopherol, and this property was unique. Among the cerebral protective drugs tested, thiopental was only slightly efficient, and pentobarbital, phenobarbital, and dimethyl sulfoxide had no effect. In addition, nizofenone was found to scavenge a stable free radical, diphenyl-p-picrylhydrazyl, but the barbiturates did not. These findings suggest that there is no intimate relationship between cerebral protective effect and free radical scavenging action.

Animals↗