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Biomedical subjects

Y Nishimura

Publications and source records attributed to Y Nishimura.

At least 487 records · Page 27Linked to original sources
PubMed1996

Effects of dietary manganese contents on 54Mn metabolism in mice.

Several parameters of 54Mn metabolism were noted in mice maintained on diets with manganese contents of 80 to 8000 mg/kg. Excretion of 54Mn was promoted as the dietary manganese contents increased. Clearance of 54Mn from the liver, kidneys, pancreas, and spleen was markedly accelerated by feeding mice a high-manganese diet, but clearance from the muscles, femurs, and brain was relatively insensitive to the dietary manganese. Manganese concentrations in the tissues were regulated homeostatically upto the dietary manganese content of 2400 mg/kg, but marked accumulations of manganese occurred when mice were given 8000 mg/kg diet. No toxic symptoms were found up to the 2400 mg/kg diet, but consumption of the 8000 mg/kg diet was less than for other diets. These results suggest that an oral intake of excess manganese is effective for promoting the excretion of 54Mn from a body contaminated with this isotope.

Animals↗
PubMed1996

Cathepsin B in the growth of colorectal cancer: suppressive effect of leupeptin on the growth of DMH-induced rat colon neoplasm.

Cathepsin B, a thiol protease, has been reported to be involved in cancer progression and metastasis. The suppressive effects of two kinds of protease inhibitors, leupeptin and dietary camostate (FOY-305), on tumorigenesis and progression in 1, 2-dimethylhydrazine (DMH)-induced rat colon neoplasm were examined in relation to tissue cathepsin B activity. Male Donryu rats were treated with leupeptin or FOY-305 during or after the administration of DMH. There were no significant differences in average tumor numbers among all DMH-treated groups. However, the percentage of small tumors was significantly higher in the group in which leupeptin was supplied during DMH administration. This trend was not recognized in the FOY-305-treated groups. The ratio of cathepsin B activity in the tumors to that in the tumor-bearing tissue (T/Tb) was significantly increased with increasing tumor size (P = 0.009). The cathepsin B activity levels in the tumor-bearing mucosa in the groups which received leupeptin or FOY-305 following DMH treatment were both significantly lower than that in the group which received neither protease inhibitor (P = 0.046 and P = 0.0067, respectively). The results obtained indicate that leupeptin may have suppressed tumor growth by lowering the tissue cathepsin B activity.

1,2-Dimethylhydrazine↗
PubMed1996

Cathepsin B in the growth of colorectal cancer: increased activity of cathepsin B in human colorectal cancer.

Cathepsin B, a thiol protease, is involved in cancer metastasis. To clarify the role of cathepsin B in tumor progression in human colorectal cancer, the relationship between its activity, immunohistochemical staining, and clinical tumor progression was investigated. Cathepsin B activity in adenocarcinomas was significantly elevated compared with that in the tumor-bearing tissue. Furthermore, the tumor/tumor-bearing tissue (T/Tb) ratio of the activity was significantly higher than that of colorectal adenoma. Immunohistochemical studies demonstrated intense staining in the cancerous tissue. With respect to the clinical stage of tumors, the activity tended to be higher in tumors that had invaded the serosa or subserosa than in those that invaded the proper muscle. The results suggest that cathepsin B participates in the progression of human colorectal cancer, and its increased expression is a sensitive marker of the differentiation between colorectal adenoma and adenocarcinoma.

Adenocarcinoma↗
PubMed1996

Velopharyngeal closure and the longus capitis muscle.

The dynamic mechanism of velopharyngeal function not only in normal individuals but also in patients with velopharyngeal insufficiency, which is mainly related to cleft palate, has been the subject of considerable interest and controversy. Recently, in order to clarify velopharyngeal movement in the valvular action on phonation we examined dynamic MR images of this area taken in the transverse plane in parallel with the muscle sling of levator veli palatini. In cases in whom the closure pattern in that plane is circular, detailed observation revealed a very interesting result; that is, the longus capitis muscle, one of the group of anterior vertebral muscles, is directly involved in velopharyngeal valving function. It has not previously been reported that the longus capitis muscle acts as one of the velopharyngeal closure muscles, in addition to levator veli palatini. The present study demonstrated that contraction of the muscle contributed to velopharyngeal closure by forward movement of the pharyngeal wall.

Adolescent↗
PubMed1996

[A case of diffuse idiopathic skeletal hyperostosis (DISH) with various neurological complications].

A 71-year-old female presented with a 10-year history of slowly progressive gait disturbance and dorsolumbar pain. Motion of he neck and trunk was severely restricted. She showed decreased sensation of vibration and position in the upper and lower limbs and had Romberg's sign. Hyperesthesia of touch sensation was distributed in a stocking pattern. She showed hyporeflexia and pathological reflexes in lower limbs. Her gait was ataxic and spastic. Laboratory examination of blood and urine revealed no remarkable findings. Radiographic examination revealed ligamentous calcification and ossification along the anterolateral aspect of the vertebral column at several levels, and there was ossification of hte ligament and tendon attachment to the bone at extraspinal sites. The radiographic features were characteristic of diffuse idiopathic skeletal hyperostosis (DISH). Computed tomography at lower thoracic and lumbar vertebral portions showed compression of the spinal cord by ossification of the flavatum ligament. The conduction velocity of tibial nerves and sural nerves were delayed, and the mechanism of the occurrence of peripheral nerve lesions in this patient could be explained by extrinsic compression by heterotopic calcification or some metabolic factor due to DISH.

Aged↗
PubMed1996

[Pulmonary artery banding using expanded polytetrafluoroethylene suture].

Pulmonary artery banding (PAB) is essential for infants of complicated cardiac anomaly without pulmonary stenosis, especially those who require future Fontan type correction. In order to avoid pulmonary artery branch stenosis or uneven growth we utilize expanded polytetrafluoroethylene (E-PTFE) suture (Gore-Tex suture, CV-0) as a banding material. We performed three PABs (two newborns and one infant) with this suture. All children were doing well after the banding and no one revealed residual pulmonary hypertension or pulmonary artery distortion in the postoperative catheter study. One patient successfully underwent total cavopulmonary connection eight months after PAB. We believe E-PTFE suture is an advantageous material of PAB for newborns and young infants.

Female↗
PubMed1996

[Relationship between diaphragm weight and body composition].

To study the relationship between diaphragm weight and body composition, we measured fat body mass and lean body mass by dual-energy X-ray absorptiometry (XR-26, Norland), and weighed the diaphragms of patients at autopsy. The subjects were 22 patients with various diseases (13 men and 9 women, aged 72.6 +/- 9.5 years). In 8 of the patients, respiratory muscle strength was assessed with maximal pressure at the mouth. The diaphragm weight was 185.2 +/- 58.2 g and it correlated significantly with lean body mass (r = 0.77, r = 0.73, p < 0.01). Maximal inspiratory pressure at TLC correlated significantly with diaphragm weight. These results show that respiratory muscle strength is related to diaphragm weight and that analysis of body composition may be useful in assessing changes in the mass of the diaphragm.

Absorptiometry, Photon↗
PubMed1996

Trimethadione N-demethylation by rat liver CYP2E1 in vitro.

Trimethadione (TMO) is a model drug utilized for estimation of hepatic metabolism in clinical studies, and it was reported that TMO N-demethylase activity was inhibited by CYP2E1 inhibitors and substrates in rat in vivo. This study was performed to investigate the involvement of the CYP2E1 subfamily on TMO N-demethylation in vitro and to clarify these inhibitory mechanisms. The effects of acetone (AC), imidazole (IM) and N-nitrosodimethylamine (NDA) on TMO N-demethylation were studied in vitro. Rat hepatic microsomal fractions were employed as the enzyme source of TMO N-demethylase and the activity was determined by the production of dimethadione (DMO). DMO was analyzed by a GC/FTD equipped with a narrow-bore capillary column. TMO N-demethylation was biphasic by the graphic analysis of Eadie-Hofstee plots; this suggests the involvement of at least two enzymes in TMO metabolism in the rat. The kinetic parameters for the formation of DMO were analyzed graphically using double-reciprocal plots. The apparent K(m1), K(m2) and Vmax1, Vmax2 values for DMO formation were 4, 20 mM and 182, 595 pmol/mg protein/min, respectively. AC and IM inhibited TMO N-demethylase activity competetively. However, mixed inhibition kinetics was observed by NDA. Furthermore, TMO N-demethylase activity was inhibited by antiserum to CYP2E1 by 62% and CYP3A2 by 46%. These results indicate that the CYP2E1 subfamily is the major enzyme involved in TMO N-demethylation in rat in vitro although the CYP3A2 is also involved in this transformation.

Animals↗