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Biomedical subjects

M Toyama

Publications and source records attributed to M Toyama.

At least 91 records · Page 5Linked to original sources
PubMed1988

Interhemispheric epithelial cyst. Case report.

We report a rare case of a 54-year-old woman with an interhemispheric epithelial cyst. This will be the first report of an interhemispheric epithelial cyst without callosal agenesis. A partial excision of the cyst wall has led to her recovery with no evidence of recurrence. Ultrastructural studies suggest that the cyst was derived from the primitive neuroepithelium. We discuss the pathogenesis of the interhemispheric epithelial cyst.

Brain Diseases↗
PubMed1988

Assessment of L-ascorbic acid requirement for prolonged survival in ODS rats and their susceptibility to urinary bladder carcinogenesis by N-butyl-N-(4-hydroxybutyl)nitrosamine.

Assessment of L-ascorbic acid requirement for prolonged survival in ODS (genotype: od/od) rats and their susceptibility to urinary bladder carcinogenesis by N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) were examined. In ODS rats without L-ascorbic acid synthesizing ability, the 50 ppm dietary total ascorbic acid (TAA) was insufficient to survive for 4 weeks, the 250 ppm dietary TAA was sufficient to survive for 36 weeks. In examination of BBN treatment, ODS rats--although showing a lower availability of TAA than the heterozygotes (+/od) and normal (+/+) rats with L-ascorbic acid synthesizing ability--were equally susceptible to bladder carcinogenesis.

Animals↗
PubMed1987

Influences of strain and diet on the promoting effects of sodium L-ascorbate in two-stage urinary bladder carcinogenesis in rats.

The influences of strain and diet on the promoting effects of sodium L-ascorbate (SA) on two-stage urinary bladder carcinogenesis was investigated in male F344 and Lewis rats. Two kinds of commercial basal diets, Oriental MF and Clea CA-1, were used. Rats were given 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine in their drinking water for 4 weeks and then basal diet with 5% SA or without SA for 32 weeks. Treatment with SA increased the induction of neoplastic lesions of the urinary bladder in rats initiated by 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine. The promoting effect of SA for urinary bladder carcinogenesis was: F344 strain-Oriental MF diet greater than Lewis strain-Clea CA-1 diet greater than F344 strain-Clea CA-1 diet = Lewis stain-Oriental MF diet. In both strains or with both diets, SA-treatment increased the urinary pH and the concentrations of sodium ion and total ascorbic acid. These results demonstrate that strain and diet strongly influence susceptibility to the SA-promoting effects in rat urinary bladder carcinogenesis.

Animals↗
PubMed1987

Effect of GnRH-associated peptide on prolactin secretion from human lactotrope adenoma cells in culture.

The effect of GnRH-associated peptide on PRL secretion by human pituitary lactotropes in culture was studied. Pituitary adenomas obtained at selective transsphenoidal adenomectomy from a patient with prolactinoma, and two patients with mixed GH- and PRL-secreting pituitary adenomas were cultured in monolayer. When cells were incubated with dopamine (10 nmol/l), a significant inhibition in PRL secretion was observed in all the experiments, which was blocked by co-incubation with haloperidol. In mixed GH- and PRL-secreting adenoma cells, dopamine likewise decreased GH secretion. Incubation of cells with synthetic GnRH-associated peptide at concentrations up to 100 nmol/l, on the other hand, failed to affect both PRL and GH secretion. These results suggest that synthetic GnRH-associated peptide has no inhibitory effect on PRL secretion in human pituitary lactotropes.

Adenoma↗
PubMed1987

[A case of intrasellar meningioma with panhypopituitarism and hyperprolactinemia].

A case of intrasellar meningioma is reported. A 49-year-old woman was admitted to our hospital on July 22, 1985, complaining of reduced visual acuity and visual field defect. Visual acuity was 0.6 in the right eye and 0.1 in the left eye. Visual field examination revealed upper temporal quadrantanopsia on the right side and incomplete temporal hemianopsia on the left side. Ocular fundi were normal. X-ray films of the skull showed a balloon-shaped sella turcica with "double floor". CT scan showed a isodense mass with central low density occupying the intrasellar and suprasellar region. After administration of contrast medium, almost homogenous enhancement was noted. Bilateral carotid angiographies demonstrated that horizontal portion of the right anterior cerebral artery was raised. No tumor blush was evident. Endocrinologic function tests confirmed a complete deficit of the anterior lobe hormones except for elevated serum prolactin level of 110 ng/ml. She showed no galactorrhea. On August 6, 1985, the sella turcica was reached via the transsphenoidal rhinoseptal approach. The sella floor and dura matter were intact. The grey, soft and necrotic tumor tissue was encountered and bleeding was controllable. The tumor extending to suprasellar region was firm in consistency. Pathologically, the tumor was a typical meningothelial meningioma. Postoperatively, visual field defect improved and visual acuity was recovered on the right side immediately. Postoperative CT scan showed a thin residual enhanced lesion, which was the attachment of the tumor. It seemed to be the elevated diaphragma sellae. Clinical observation, radiological and endocrinological findings of intrasellar meningioma are similar to that of non-functioning pituitary adenoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1985

Amitrole: strain differences in morphological response of the liver following subchronic administration to mice.

Strain differences in the induction of hepatocellular preneoplastic lesions by amitrole were examined in NOD, ICR and DS mice. Amitrole was administered to mice in drinking water at a dose of 1% for 6 months. After 3 months, hyperplastic nodules (HN) and severe fibrosis were prominent in NOD mice but not in other strains. On examination at 6 months, both number and size of HN were greatest in the NOD strain. Furthermore, a hepatocellular carcinoma was found in a NOD mouse, suggesting that this strain is more susceptible to amitrole-induced hepatocarcinogenesis than are ICR or DS mice.

Amitrole↗
PubMed1985

[Abnormal left ventricular endocardial structures detected by two-dimensional echocardiography in systemic lupus erythematosus].

This is a report of abnormal endocardial structures on the left ventricular wall as visualized by two-dimensional echocardiography (2-D echo) in patients with systemic lupus erythematosus. Abnormal endocardial structures, arising from the left ventricular endocardium and appearing to proliferate into the cavity, were found in 11 (20%) of 54 patients. The most frequently involved site was posterobasal left ventricular wall in the parasternal long-axis view, and the posterolateral segment of the left ventricle including the anterior and posterior papillary muscles in the parasternal short-axis view. M-mode echocardiograms, simultaneously recorded with 2-D echo, revealed abnormal structures of increased intensity adjacent to the endocardium with thicknesses of 4 approximately 7 mm. Most of the abnormal endocardial structures were observed in patients in the active phase by 2-D echo, and they appeared to regress with steroid therapy. In one autopsy case, fibrous endocardial thickening suggesting healed endocarditis was present in the anterior papillary muscle as observed by 2-D echo. Their location and response to steroid therapy suggests that these abnormal echoes could represent Libman-Sacks endocarditis.

Adult↗
PubMed1984

Identification and quantification of the left-to-right shunt in adults with atrial septal defect by two-dimensional negative contrast echocardiography.

Negative contrast echocardiograms of two-dimensional long axis view of the right ventricle and the atrium were compared with the results of cardiac catheterization and surgical findings in 33 adults with atrial septal defects. Contrast echocardiographic evidence of atrial communication was noted in 30 cases (91%), and, in 28 cases, the negative contrast during one cardiac cycle could be measured. This could be applied even in cases with a small left-to-right shunt or with Eisenmenger's syndrome. No obvious difference in the behavior of negative contrast was documented among the cases with distinct types of septal defects. The maximum negative contrast area and the duration of appearance in one cardiac cycle were related to the pulmonary-to-systemic flow ratio. However, a significant overlap and considerable effects of transducer angulation on measurements were documented. Thus, negative contrast echocardiography may be widely used for the noninvasive identification of a left-to-right shunt in atrial septal defects. However, the method is not appropriate for a precise quantification of three-dimensional shunt flow.

Adolescent↗