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Biomedical subjects

F Sasaki

Publications and source records attributed to F Sasaki.

At least 271 records · Page 15Linked to original sources
PubMed1980

Role of the ovary in the sexual differentiation of prolactin and growth hormone cells in the mouse adenohypophysis during postnatal development: a stereological morphometric study by electron microscopy.

To clarify the role of the ovary in the sexual differentiation of prolactin and growth hormone cells, the anterior pituitary glands of mice ovariectomized before or after puberty were studied by a stereological morphometric technique with the electron microscope. A marked sex difference was observed in the relative proportions of these two types of cells in normal adult control animals. In male mice about 52% of anterior pituitary cells were growth hormone cells and about 10% were prolactin cells, while in female mice prolactin cells represented about 39% and growth hormone cells about 37% of the anterior pituitary cell population. Ovariectomy before puberty reduced the proportion of prolactin cells to about 10% and increased growth hormone cells to about 50% of the cell population. The size of prolactin cells and the development of their cell organelles was also reduced. Ovariectomy after puberty had less marked effects. These results suggest that ovariectomy before puberety induced the male phenotype by inhibition of the differentiation of prolactin cells and stimulation of the differentiation of growth hormone cells. The significance of these results in relation to the sexual differentiation of the pituitary gland is discussed.

Aging↗
PubMed1980

Histogenesis and distribution of red and white muscle fibres of urodelan larvae.

A histochemical and electron microscopical study has been made of the myotomal musculature of an urodelan (Hynobius tokyoensis) tadpole tail and trunk. In older larvae (stage 64) two main types of fibre (small red and large white) could be distinguished on the basis of differences in fibre size, succinic dehydrogenase and adenosine triphosphatase activities, and fine structural features. The red fibres were superficial to the white ones except at the level of the notochord, where red and white were mixed in mosaic fashion. The superficial and deep red fibres were similar in their histochemical and fine structural characteristics.

Adenosine Triphosphatases↗
PubMed1979

Suppression of tuberculin reactivity during natural rubella. Observations with 54 patients.

Fifty-four patients with previously positive tuberculin reactions were followed for tuberculin sensitivity, between the incubation period of natural rubella and the 40th day after the onset of rash. In many instances, tuberculin sensitivity was partially or completely depressed beginning in the incubation period and extending for up to 4 weeks after rash onset. Two of 3 cases of subclinical rubella infection also showed this phenomenon. The highest incidence of negative reactions was 83% in the first 3 days after rash onset. A few subjects had a larger skin reaction to tuberculin than the baseline reading during the 2 to 5 weeks after rash onset.

Adolescent↗
PubMed1978

Light and electron microscopic investigation of ATPase activity in musculature during anuran tail resorption.

The histochemical activity of adenosine triphosphatase (ATPase) was studied at light and electron microscopic levels in larval tail musculature of Rana catesbeiana and Rana ornativentris during late metamorphic stages. The presence of low, moderate or dark reaction of K2-EDTA-preincubated Ca++-ATPase was correlated with the variable degree of degeneration of white fibres even at the late stage of tail resorption. The reasons for an increase in this ATPase activity in degenerating white muscle fibres are discussed. Irrespective of the degree of degeneration, all red fibres showed high ATPase reaction. During myocytolysis, it is shown that the SR vesicles accumulate electron dense amorphous material. The degree of myofibrillar disintegration correlated with decrease in ultrastructural reaction product for Mg++-ATPase. Although grouped atrophy of muscle fibres (as seen in Xenopus laevis, den Hartog Jager et al., 1973, 1975) was absent in musculature of resorptive tails, ultrastructural characteristics including proliferation of SR and dilation of its vesicles represent alteration of the normal neural influence on the skeletal muscle fibres.

Adenosine Triphosphatases↗
PubMed1978

Light and electron microscopic study of adenosine triphosphatase activity of anuran tadpole musculature.

The histochemical activities of succinic dehydrogenase (SDH) and Ca++-activated ATPase (pHs 7.4 and 9.4) were studied in the larval tail musculature of Rana japonica, Rana catesbeiana and Rana ornativentris. The ATPase reaction product was detected by both light and electron microscopy. 'Red' and 'white' muscle fibres, as distinguished by SDH, showed high and low Ca++-ATPase reaction, respectively, at pHs 7.4, 9.4 and following preincubation in cold K2-EDTA solution. The ultrastructural investigation of Ca++-ATPase reaction at pH 7.4 by the Ca++-citrophosphate technique demonstrated electron-dense reaction product in association with A, I and 'Z' bands, intermyofibrillar (SR) compartment and the mitochondrial inner chamber. However, Pb++ precipitation technique demonstrated Mg++-activated myosin ATPase activity at pH 9.2 ultrastructurally. The present histochemical data suggest that the anuran larval tail 'red' muscle fibres are possible 'slow,' and emphasize a possible lack of correlation between the speed of contraction with their ATPase activity. Moreover, 'red' muscle fibres of the anuran tai- musculature are not equivalent to 'Type I' fibres of higher chordates.

Adenosine Triphosphatases↗
PubMed1978

[Yolk sac tumor (author's transl)].

An analysis was made from a histopathological and clinical standpoint of 6 cases of yolk sac tumor over a period of 15 years, treated in the first surgical department of the University of Hokkaido. All these cases, with the exception of one retroperitoneal tumor, were diagnosed as embryonic carcinomas before the study. AFP were examined throughout the duration of treatment and their levels reflected changes corresponding to the effects of treatment and recurrence. They were seen in the form of special fluorescence in the tumor cells using the antibody immunofluorescence method. Radiotherapy and chemotherapy may be effective, but the prognosis of these tumors is poor. Amongst the cases mentioned, only the child with a tumor of testicular origin is in good health.

Child, Preschool↗