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Biomedical subjects

T Matsuhashi

Publications and source records attributed to T Matsuhashi.

36 records · Page 2Linked to original sources

Inhibition of N-butyl-N-(4-hydroxybutyl) nitrosamine-induced urinary bladder tumor in rats by alpha-difluoromethylornithine.

The therapeutic effects of alpha-difluoromethylornithine (DFMO) on rats with bladder tumors induced by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) were examined. Eight-week-old male Wistar rats were given 0.05% BBN in their drinking water for a period of 4 weeks. Therapy (0.1% DFMO in their drinking water) was started at week 4 and all rats were killed at week 60. DFMO was seen to significantly reduce the incidence, the mean number and the total size of tumors. No side-effects of DFMO were noted, except alopecia, which started at month 7 of the therapy.

Animals↗

Reduction of 2,4-dinitrotoluene by Wistar rat liver microsomal and cytosol fractions.

2,4-Dinitrotoluene (2,4-DNT) is an important industrial nitroaromatic compound. 2,4-Diaminotoluene (2,4-DAT), one of the urinary metabolites of 2,4-DNT, is carcinogenic when fed to rats. The objectives of these studies were to determine whether 2,4-DAT was formed from 2,4-DNT in rat liver and to clarify the nature of enzymes responsible for reduction of 2,4-DNT to 2,4-DAT. Data obtained from thin-layer and high-pressure liquid chromatography indicated that metabolites produced by microsomal preparations were 2-amino-4-nitrotoluene (2A4NT) and its isomer (4A2NT). This microsomal activity is probably mediated by cytochrome P-450 because the reduction is blocked by carbon monoxide and primary amines [aniline, n-octylamine, and 2,4-dichloro-6-phenylphenoxyethylamine (DPEA)]. In contrast, 2,4-DNT was metabolized via 2A4NT and 4A2NT to 2,4-DAT by cytosolic preparations. The greatest part of the reduction activity was due to cytosolic xanthine oxidase because the reduction was blocked by allopurinol. The results of this investigation suggest that reduction of 2,4-DNT to 2,4-DAT by cytosolic xanthine oxidase may play a role in 2,4-DNT hepatocarcinogenicity.

Animals↗

[Artistic production in epilepsy].

In the epileptic's relation to the world, there is--as a particular way of being--an opposition between two constitutive moments: the world of the dark mass and the world of the light tone of colour as moments of an entirety. This can be seen symbolically in pictures as a contrast between light with an upward trend towards heaven and darkness as an earthy mass with a downward tendency. The two worlds are one at the same time, with diverging trends coexisting in a dynamically flowing organic interrelationship. This is combined with a specific religious atmosphere. From this point of view the attempt is made to gain an understanding of the condition of being ill with epilepsy.

Adult↗

Small angiomyolipoma of the liver diagnosed by fine-needle aspiration biopsy under ultrasound guidance.

The first reported case of small hepatic angiomyolipoma to be diagnosed by fine-needle aspiration biopsy (FNAB) is described. A 53 year old man presented with a tumour in segment VI of the liver measuring 0.9 x 0.8 cm. The tumour was hyperechoic on ultrasound examination, showed relatively low density (+ 33 Hounsfield units) on computed tomography (CT), and was hypervascular on angiography. Computed tomography during arterial portography demonstrated a perfusion defect. Magnetic resonance imaging (MRI) revealed high intensity by both T1- and T2-weighted imaging. Diagnosis could not be obtained by these imaging modalities, but it was established successfully by FNAB under ultrasound guidance. Histologically, the tumour was an angiomyolipoma made up of three components: blood vessels, smooth muscle and fatty tissue. Surgery is unnecessary for this benign condition, and the patient has been followed up. Ten months later, the patient is currently doing well without growth of the hepatic angiomyolipoma.

Angiomyolipoma↗

Suppression of the hydrazine-induced formation of megamitochondria in the rat liver by coenzyme Q10.

The effects of coenzyme Q10 (CoQ10) on the hydrazine-induced changes in the structure of mitochondria and those in antioxidant systems of the liver were investigated using rats as experimental animals. Animals were placed on a powdered diet containing 1.0% hydrazine for 7-8 days in the presence or absence of the combined treatment with CoQ10. Results obtained were as follows: (a) treatment of animals with CoQ10 prevented the hydrazine-induced formation of megamitochondria in the liver; (b) changes observed in the liver of the hydrazine-treated animals in comparison to the control were increases in the contents of alpha-tocopherol and CoQ analogs, increases in the levels of lipid peroxidation, decreases in the level of reduced glutathione with increases in that of oxidized glutathione, and increases in the ratio of unsaturated to saturated fatty acids in phospholipid domains of mitochondrial membranes; and (c) administration of CoQ10 to hydrazine-treated animals suppressed enhanced lipid peroxidation and improved lowered adenosine diphosphate/O ratios of mitochondria. The present data suggest that CoQ10 suppresses the hydrazine-induced formation of megamitochondria by scavenging free radicals generated from hydrazine and its metabolites.

Animals↗