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Biomedical subjects

M Kamimura

Publications and source records attributed to M Kamimura.

At least 91 records · Page 5Linked to original sources

Polypoid vocal folds. A 10-year review of 191 patients.

During the 10 years from 1971 to 1980, 191 patients with polypoid vocal folds were seen at the Department of Otolaryngology, Kurume University Hospital. A retrospective review of the clinical records of these 191 patients was completed. Results were the followings: 1) There was no marked difference in incidence between male and female; 2) The incidence was high in the age groups of 40 years or older; 3) Most patients were smokers; 4) Bilateral lesions were much more frequent than unilateral lesions; 5) Long-lasting hoarseness was the commonest symptom; 6) Vocal abuse, alcohol drinking and air pollution did not prove to be etiologic factors; and 7) No significant differences in subjective voice improvement were found between the stripping and the sucking technique.

Adolescent↗

[Topical application of ACNU for the treatment of mycosis fungoides].

The effects of topical chemotherapy of 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) on the lesions of mycosis fungoides were evaluated in 7 patients, ranging in age from 44 to 79 years old. Either 0.2% or 0.4% concentration of ACNU, in ointment and ethanol was used. 0.4% ACNU ethanol solution was effective in bringing the plaque lesions under satisfactory control with a complete clearance. ACNU was painted two to three times a week with a maximum dose of 50mg. Irritation and erosion of the applied areas were the major side effects, which were however, controlled by topical steroid ointment. No serious side effects of marrow and liver function were found even when ACNU was applied as long as 40 months (total ACNU dose: 16 gm). Histologically the cleared lesions revealed the thinning of epidermis, almost complete loss of lymphocytic infiltrates and fibrosis of dermis which was density infiltrated by lymphocytes prior to the ACNU therapy. Thus, topical chemotherapy of ACNU appears to be encouraged for modifying the plaque lesions of mycosis fungoides.

Administration, Topical↗

The migration of presumptive primordial germ cells through the endodermal cell mass in Xenopus laevis: a light and electron microscopic study.

Presumptive primordial germ cells (pPGCs) were examined during migration from their deep endodermal position to the endodermal crest in Xenopus laevis, using light and electron microscopy with Epon sections, and several morphological characteristics of pPGCs, associated with their migration, were revealed. pPGCs displayed polymorphism, with smooth contours. The intercellular space around the PGCs was large and variable in width and cytoplasmic processes from pPGCs were occasionally observed in it. It was shown quantitatively that pPGCs at the migratory stage had a tendency to move with the leading end, towards which the nucleus was localized, dragging the germinal plasm behind. These polarized pPGCs were frequently associated with large intercellular spaces, both at their leading and trailing ends. Cytoplasmic processes of polarizing pPGCs found in the large intercellular space at the leading end were conspicuous. Ultrastructurally, the nuclei of pPGCs were euchromatic, and the nucleolus was prominent. The germinal plasm at the light microscope level corresponded to the cytoplasmic area near the nucleus where a large number of mitochondria with well-developed cristae and most of the other organelles were aggregated. Centrioles and centriole-associated microtubules observed in the aggregate were thought to be important structures responsible for the cell polarization mentioned above. It was demonstrated quantitatively that the size of mitochondria in pPGCs was larger on average than that of mitochondria in neighbouring somatic endodermal cells. Numerous irregularly shaped small yolk platelets characterized pPGCs. These ultrastructural features suggested that pPGCs were in an activated metabolic state. It was concluded that the migration of pPGCs was attributable to active movement with high cell metabolism, causing the formation of cell processes and intracellular polarization.

Animals↗

Observations on the migration and proliferation of gonocytes in Xenopus laevis.

The process of primordial germ cell formation in the normal course of development of Xenopus laevis was examined with a light microscope on paraffin and Epon sections of embryos or tadpoles, extending over the period from the gastrula to the feeding tadpole stage. Positional changes of gonocytes with development were nearly the same as those reported on the same species by Blackler (1958) and Whitington & Dixon (1975). The following points were newly demonstrated. Gonocytes which have been located in a deep endodermal position till mid tail-bud stage come to be located in a rather peripheral region of the endoderm cell mass at stage 31 (late tail-bud), suggesting that the initial step of migration of the gonocytes towards the future genital ridge has already begun at this stage. Gonocytes at stages 33/34 and 35/36 were observed in a more dorsal part of the endoderm than at stage 31. Gonocytes which seem to have begun their migration are roundish in external shape and have a large intercellular space around them. At stage 40 gonocytes were located in the dorsal endodermal crest, and at stage 41 gonocytes were found with cell bodies extending over both the dorsal endoderm crest and the dorsal mesentery, indicating that the separation of the gonocytes from the endoderm was in progress at this stage. The present results seem to indicate that gonocytes migrate not passively but actively from the deep endodermal position to the genital ridge, passing through the dorsal mesentery. Counting the number of gonocytes at successive stages of development revealed that gonocytes proliferated exponentially throughout the developmental stages from gastrula to tadpole.

Animals↗