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Biomedical subjects

E Arai

Publications and source records attributed to E Arai.

At least 55 records · Page 3Linked to original sources

Biomechanical behavior of the posterior elements of the lumbar spine under loading--a study of stress analysis by means of three dimensional photoelastic experiments.

To investigate the biomechanical behavior of the lumbar posterior elements under loading, stress analysis was carried out. The three dimensional photoelastic method was used for stress analysis in this study. The forces applied to the superior and the inferior articular facets were concentrated on the pars interarticularis and transmitted to the pedicle. However, almost no stress was generated in the lamina. Highly stressed areas were found in the pars interarticularis and around the lateral recess. The highest compressive stress was present in the pars interarticularis. The deformation pattern of the lumbar spinal canal was recognized and it became flat as the lateral recess was narrowed and deepened. These results very interestingly correspond to the fact that spondylolysis and lumbar canal stenosis are found in the above-mentioned areas clinically.

Biomechanical Phenomena↗

[Metastatic penile tumors: report of three cases].

Metastatic tumor of the penis is uncommon in spite of its rich blood supply, abundant vascular space and the proximity of the pelvic organs which have a high incidence of malignant neoplasms. We report three cases of metastatic penile tumors. The primary sites of these cases were the left ureter, the right kidney and the rectum. We review and discuss sixty two cases collected from the Japanese literature, including our cases.

Adenocarcinoma↗

[A case of renal oncocytoma].

We report a case of renal oncocytoma and review 158 cases in the literature. The patient was a 75-year-old woman whose chief complaint was epigastric discomfort without any urological symptoms. The right renal tumor was incidentally discovered by ultrasonography. Its angiographic patterns such as spoke-wheel appearance and homogeneous nephrogram were "characteristic" of renal oncocytoma. We diagnosed it as oncocytoma by microscopical and ultrastructural observation.

Adenoma↗

[Effect of alpha-methyl-para-tyrosine on "methamphetamine-induced sterotype and hypermotility" of reserpinized rats (author's transl)].

Previously we have found such "bizarre stereotypy" as persistent and bloody biting activity at the legs or the tail of himself or of the cage mate given methamphetamine (MAPT, 10 mg/kg) 24 hrs-48 hrs after long term-administration of reserpine (RE). The present investigation examined the effect of inhibition of dopamine synthesis in brain on MAPT-induced "bizarre stereotypy" and hypermotility of RE-treated rats. Male albino Wistar rats aged 4 weeks were injected intraperitoneally with RE (1.25 mg/kg) or 0.9% saline solution (1.25 ml/kg) every two days for 13 days. Twenty-two hrs after the last injection, rats received alpha-methyl-para-tyrosine ( alpha-MPT, 50 mg/kg, 125 mg/kg, 250 mg/kg i.p.) or its vehicle (1 ml/kg i.p.) and 2 hrs later, MAPT. MAPT induced continuous licking and biting at the metal wire of the cage floor in saline-treated rats and also "bizarre stereotypy" in RE-treated rats, but these activities were completely suppressed by pretreatment of alpha-MPT in each dose given (especially in 125 mg/kg, 250 mg/kg). Pertaining to the locomotor activities of saline-treated rats, the horizontal movements were especially enhanced by MAPT, however, the vertical movements remained unchanged. Alpha-MPT partially inhibited such horizontal movements while it potentiated the vertical movements. Locomotor activities of RE-treated rats were depressed one day after the last injection of RE, however, after the MAPT, these activities counts were increased considerably and were also higher in comparison to the counts of saline-treated rats given MAPT. These hypermotilities in RE-treated rats were partially antagonized by pretreatment with alpha-MPT. It is suggested that MAPT-induced "bizarre stereotypy" of RE-treated rats is mediated by the accelerative effect of RE on MAPT-induced dopamine synthesis, while MAPT-induced hypermotility of RE-treated rats is partially related to such an acceleration of dopamine synthesis.

Animals↗

Chromosomal anomalies of preimplantation rabbit blastocysts and human artificial abortuses in relation to maternal age.

It is well established that in man there is a higher frequency of chromosomally and phenotypically abnormal offspring and a decline in fertility as maternal age increases. This paper describes preliminary work on some chromosomal aspects of 5- and 6-day old preimplantation rabbit embryos, with attention to maternal age dependence of chromosome anomalies. Chromosome preparations were made by a modification of the method of Shaver and Carr (1967). Two trisomic blastocysts were observed among 50 embryos examined from 10 does of 40 to 52 months of age, that is, 45XY with an extra submetacentric chromosome and 45XX with an extra acrocentric chromosome. In man, three trisomies (47XX, G+, 47XX, D+, and 47XY, G+), one monosomy (45X or 45XX, C-) and one double trisomy (48XY, C+, E+ or 48XXY, E+) were karyotyped out of 32 early induced abortuses from women older than 40. Among the 22, induced abortuses analyzed from women between 35 and 39, one trisomic embryo of 47XY, G+ was observed.

Abortion, Induced↗