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Biomedical subjects

Y Kitamura

Publications and source records attributed to Y Kitamura.

At least 829 records · Page 46Linked to original sources
PubMed1978

Decrease of mast cells in W/Wv mice and their increase by bone marrow transplantation.

Production of tissue mast cells was evaluated in genetically anemic mice of W/Wv genotype and was found to be abnormal. In the skin of adult W/Wv mice the number of mast cells/cm was less than 1% of the number observed in the congeneic +/+ mice. No mast cells were detectable in other tissues of the W/Wv mice. After transplantation of bone marrow cells from +/+ mice the number of mast cells in the skin, stomach, caecum, and mesentery of the W/Wv mice increased to levels similar to those of the +/+ mice. These results show that the W/Wv mouse is a useful tool for the investigations concerning the physiologic roles and the origin of mast cells.

Anemia, Macrocytic↗
PubMed1978

Hematologic changes during spleen colony development in nonirradiated mice.

The mechanism of spleen colony formation in nonirradiated mice was investigated. When the spleen cells of C57BL mice immunized against CBA-T6T6 mice were injected into the nonirradiated BT6F1 (C57BL X CBA-T6T6) hybrid mice, the number of hematopoietic stem cells (CFU-S of C57BL mouse origin that settled in the spleen of the BT6F1 mice continued to decrease in the first 9 days and then started to increase, with a doubling time of about 36 hr. Colonies were detected on the surface of the spleen 16-22 days after the cell injection. The slower appearance of spleen colonies in nonirradiated mice (compared with 6-10 days in the irridiated animals) appears to be due to retarded start of differentiation and to the prolonged doubling time of CFU-S in non-irradiated mice.

Animals↗
PubMed1977

Tissue fibrinolytic activity of allergic contact dermatitis.

One of our co-workers was sensitized with a 1% DNCB solution in acetone. Biopsies were obtained from skin lesions 1, 2, 4, 8, 12, 24, 30, 36 and 48 hours after a challenge with 0.1% DNCB solution. In the upper dermis, a rapid decrease of tissue fibrinolytic activity was found which disappeared after 30 hours. In the lower dermis, biphasic changes were observed. Tissue fibrinolytic activity increased one hour and 12-36 hours after challenge, whereas at 48 hours, when erythema was most intensive, it decreased in comparison to the normal activity. Erythema and histological changes of the epidermis and the dermis appeared after approximately 12 hours. As for lymphocytes, T-cells were seen at first. Furthermore, B-cells were noted after approximately 30 hours when marked infiltration began to appear.

Biopsy, Needle↗
PubMed1977

A study of hypertension: participation of central adrenaergic mechanism on the angiotensin II-induced hypertension.

I. Interactions of angiotensin II and norepinephrine in the rat hypothalamus and other brainstem were studied by intraventricular perfusion or/and intravenous administration. (1) Intravenous administration of angiotensin reduced the hypothalamus norepinephrine content. (2) Intraventricularly perfused angiotensin reduced the hypothalamus norepinephrine but did not alter that in other parts of brainstem. Hypothalamus norepinephrine was reduced more by intravenous administration of angiotensin than by intraventricularly perfused angiotensin. II. The involvements of adrenergic mechanism in the central pressor effect of angiotensin II were studied through observation of blood pressure changes following injection of angiotensin II, phentolamine and propranolol into the rabbit lateral ventricle of rabbit brain.(1) Intraventricular administration of phentolamine suppressed the central mediated pressor respons of angiotensin. (2) Simultaneous intraventricular administration of propranolol enhanced the angiotensin pressor effect in anesthetized rabbits.

Angiotensin II↗
PubMed1977

Development of hematopoietic spleen colonies in nonirradiated genetically normal mice.

The question as to whether prior irradiation or injection of cytotoxic drugs is essential for the development of spleen colonies was examined in genetically normal mice. Mixtures of lymph node and bone marrow cells from C57BL mice were injected into (C57BL X CBA-T6T6) F1 hybrid mice without pretreatment. Hematopoietic nodules were observed in the spleens of F1 hybrid mice killed 18 days after injection. The average number of nodules increased linearly with increased numbers of injected bone marrow cells. Hematopoietic stem cells (CFU-S) and dividing cells in the nodules were shown to be of C57BL origin. Histologic examination showed that erythroid cell colonies predominated over granulocytic cell colonies. These results suggest that any kind of treatment that causes the depletion of CFU-S in the spleen of hosts would provide a suitable environment for the production of colonies by transplanted CFU-S.

Animals↗
PubMed1977

Sertoli cell junctions in the germ cell-free testis of the congenic mouse.

Intercellular junctions between the Sertoli cells in the germ cell-free testis of the congenic mouse were studied during ontogeny. In freeze-fracture replicas, these junctions are characterized by a great number of parallel occluding junctions, in which the particles are preferentially located in the center of the grooves in the E face. These particles appear to be arranged in discrete rows in both P and E fracture faces. In the initial stages of junction formation, large gap junctions with hexagonally packed particle aggregates and particle-free regions are observed. In the later stages, short segments of the occluding junctions are found associated with gap junctions. In later stages, the gap junctions diminish in size and number. These junctions are quite similar to those between Sertoli cells in the normal mouse and rat reported previously. The Sertoli cell junctions develop in the absence of the spermatogenic cells of this congenic mouse.

Age Factors↗