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Biomedical subjects

Y Kitamura

Publications and source records attributed to Y Kitamura.

At least 685 records · Page 38Linked to original sources

High susceptibility to ADP-induced thrombus formation in mast cell-deficient W/Wv mice.

We used mast cell-deficient W/Wv mice to clarify whether mast cell-derived heparin may play a role in inhibiting thrombus formation in the living organism. Small veins in the mesentery of W/Wv or congenic +/+ mice were stretched over an inverted microscope; a micropipette filled with varying concentrations of ADP was set close to the outside of a vein by using a micromanipulator. Thrombus formation was directly examined under the microscope. The concentration of ADP necessary for thrombus formation was significantly lower in the W/Wv mice than in the congenic +/+ mice. Furthermore, the concentration of ADP necessary for aggregation of platelets in platelet-rich plasma (PRP) was significantly lower in W/Wv mice than in +/+ mice. The higher sensitivity of PRP of W/Wv mice is not attributed to the platelets, but to the plasma, since platelets of +/+ mice suspended in platelet-poor plasma (PPP) of W/Wv mice were more sensitive to ADP than platelets of W/Wv mice suspended in PPP of +/+ mice. The present results suggest that plasma of W/Wv mice may lack any inhibitory factor(s) or contain promoting factor(s) for platelet aggregation.

Adenosine Diphosphate↗

Fate of bone marrow-derived cultured mast cells after intracutaneous, intraperitoneal, and intravenous transfer into genetically mast cell-deficient W/Wv mice. Evidence that cultured mast cells can give rise to both connective tissue type and mucosal mast cells.

Both connective tissue mast cells and mast cells grown in vitro are derived from multipotential hematopoietic stem cells, but these two mast cell populations exhibit many differences in morphology, biochemistry, and function. We investigated whether the phenotype of cultured mast cells or their progeny was altered when the cells were transferred into different locations in vivo. Cultured mast cells were immature by ultrastructure, and stained with alcian blue but with neither safranin or berberine sulfate, a fluorescent dye that binds to the heparin of connective tissue mast cell granules. By contrast, mast cells recovered from the peritoneal cavity of congenitally mast cell-deficient (WB X C57BL/6)F1-W/Wv (WBB6F1-W/Wv) mice 10 wk after intraperitoneal injection of cultured WBB6F1-+/+ or C57BL/6-bgJ/bgJ mast cells stained with both safranin and berberine sulfate. Staining with berberine sulfate was prevented by treatment of the cells with heparinase but not chondroitinase ABC, suggesting that the adoptively transferred mast cell population had acquired the ability to synthesize and store heparin. Furthermore, the recovered mast cells were indistinguishable by ultrastructure from the normal mature peritoneal mast cells of WBB6F1-+/+ mice, and contained substantially more histamine than mast cells studied directly from culture. Intravenous injection of cultured mast cells resulted in the development of safranin-and berberine sulfate-positive mast cells in the peritoneal cavity, spleen, skin, and glandular stomach muscularis propria. Mast cells also developed on the glandular stomach mucosa, but these cells stained with alcian blue rather than safranin, and did not stain with berberine sulfate. This result suggests that cultured mast cells can give rise to mast cells of either the connective tissue type or mucosal phenotype, depending on anatomical location. Furthermore, transplantation of cultured mast cells into WBB6F1-W/Wv mice had no measurable effect on the anemia of the recipient mice, suggesting a possible strategy for repairing the mast cell deficiency of WBB6F1-W/Wv mice without affecting other bone marrow-derived populations such as erythrocytes. Intravenous injection of representative connective tissue type mast cells (30-50% pure peritoneal mast cells derived from WBB6F1-+/+ mice) gave results similar to those obtained with cultured mast cells: mast cells developing in the peritoneal cavity, skin, spleen, and glandular stomach muscularis propria of WBB6F1-W/Wv recipients stained with safranin and berberine sulfate, whereas mast cells developing in the mucosa of the glandular stomach stained only with alcian blue.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Increased fructose-lysine of hair protein in diabetic patients.

Fructose-lysine, which is formed by binding glucose to lysine, is changed by acid hydrolysis into furosine. Furosine derived from fructose-lysine of hair was determined by high-performance liquid chromatography according to the method of Schleicher et al. Furosine values were significantly higher in diabetic patients than in healthy subjects, and significantly correlated with the stable components of hemoglobin A1 (HbA1) values. These results suggest that furosine, like HbA1, may become an indicator of past blood glucose control at any time in diabetic patients and be useful in investigating diabetic complications on the level of tissue.

Adult↗

Induction of histidine decarboxylase activity in the spleen of mice treated with staphylococcal enterotoxin A and demonstration of its non-mast cell origin.

Histidine decarboxylase (HDC) activity increased 13-, 7-, and 2-fold in the spleen, lung and liver, respectively, but not in other tissues of C57BL/6 mice injected i.v. with 50 micrograms/kg of Staphylococcal enterotoxin A (SEA). But even in the spleen, increase in the histamine level was only 1.5 times that of untreated mice. In genetically mast cell-deficient WBB6F1 - W/Wv mice HDC activity in the spleen increased to the same extent as in wild type WBB6F1 - +/+ mice on SEA treatment, but the histamine level in the spleen also increased 20-fold, whereas it increased only 1.4-fold in +/+ mice. These results suggest that the increases in HDC and histamine resulted from interaction of SEA with non-mast cells in tissues.

Animals↗

beta-Adrenoceptor stimulation-induced increase in the number of alpha 2-adrenoceptors of cerebral cortical membranes in rats.

Effects of pre-treatment of synaptic membranes with beta-adrenoceptor agonists and cholera toxin on [3H]clonidine and [3H]yohimbine binding were examined in rat cerebral cortex. Pre-incubation of cerebral cortical membranes with isoproterenol (10 or 200 microM) or dobutamine (1, 10 or 200 microM) at 37 degrees C for 40 min caused a significant elevation of specific [3H]clonidine binding but treatment with salbutamol (10 or 200 microM) did not. Scatchard analysis showed that 200 microM isoproterenol treatment resulted in a significant elevation of high affinity component of [3H]clonidine binding which was significantly decreased by the addition of 10 microM GTP. A significant elevation in high affinity [3H]clonidine binding was observed by treatment with 100 micrograms/ml cholera toxin, while a significant decrease in low affinity one was by the treatment. Specific [3H]yohimbine binding was also elevated by 10 or 200 microM isoproterenol treatment. It is suggested that stimulation of beta-receptors, presumably beta 1-subtype, could elevate the number of agonist and antagonist binding sites in alpha 2-receptors in synaptic membranes by partially mediated by stimulatory and/or inhibitory GTP binding regulatory proteins.

Animals↗

Precocious breast development: a case of unilateral hyperplasia of the adrenal cortex.

The case of a 14-month-old girl presenting with precocious breast development due to adrenal hyperplasia is reported. The endocrine studies revealed a slight elevation of the plasma progesterone, 17 alpha-hydroxyprogesterone, testosterone and oestrone levels, and an increased urinary oestrogen excretion. The findings of the ultrasound examination and the evidence that the oestradiol concentration in the left adrenal vein was higher than in the right adrenal vein confirmed the diagnosis of left adrenal hyperfunction. Surgical exploration revealed unilateral hyperplasia of the adrenal cortex. After adrenalectomy the plasma hormone levels and urinary oestrogen excretion fell to normal, with concomitant regression of breast tissue. The girl shows no signs of recurrence of the disorder in a 2 year follow-up. This adrenal hyperplasia might be a benign adrenal disorder causing precocious breast development.

17-alpha-Hydroxyprogesterone↗

Mast-cell precursors in the skin of mouse embryos and their deficiency in embryos of Sl/Sld genotype.

Concentration of mast-cell precursors in the skin and liver of mouse embryos was evaluated by the limiting dilution analysis. The concentration of mast-cell precursors in the liver of (WB X C57BL/6)F1 (hereafter WBB6F1)-+/+ embryos reached the maximum level at Day 15 of the pregnancy, whereas the concentration in the skin at Day 17. The concentration of 17-day skin was about 10 times as high as that of 15-day liver. Appearance of morphologically identifiable mast cells in the skin followed the increase in concentration of the skin precursors. Concentrations of mast-cell precursors in the skin and liver of mutant embryos of Sl/Sld genotype were also measured to clarify the mechanism of mast-cell depletion in this mutant. Although the concentration of mast-cell precursors in the liver of WBB6F1-Sl/Sld embryos was comparable to that of the WBB6F1-+/+ embryos, the concentration in the skin of the Sl/Sld embryos was about 1% that of the +/+ embryos. Moreover, the concentration of morphologically identifiable mast cells in the skin of the Sl/Sld embryos was about 0.1% that of the +/+ embryos. Thus, mast-cell production in Sl/Sld embryos seemed to be suppressed at two stages; (1) during deficient invasion of liver-derived precursors into the skin, or the decreased proliferation of these cells, or both of these causes, (2) during differentiation of the precursors into mast cells.

Animals↗

Age-dependent change in sensitivity of oestrogen-induced uterine cell proliferation of mice, estimated by incorporation of [125I]iododeoxyuridine.

The stimulative effects of both oestradiol-17 beta (E2) and diethylstilbestrol (DES) injections on the proliferation of uterine cells of mice were investigated by using 5-[125I]iodo-2'-deoxyuridine [( 125I]IdUrd) incorporation as an index. Female mice of (WB X C57BL/6)F1 were neonatally castrated, and the [125I]IdUrd uptake by the whole uterus was determined on days 1, 5, 10, 20, 30 and 40 after birth. The relative minimal dose (a minimal dose expressed per body weight, microgram/g b.wt) of E2 necessary for the maximal [125I]IdUrd uptake was much higher than the relative minimal dose of DES on days 1, 5, and 10, when the serum concentration of alpha-fetoprotein was relatively high. However, the relative minimal dose of E2 was comparable to that of DES on days 30 and 40, when the concentration of alpha-fetoprotein was negligible. The difference between the effect of injected E2 and DES during neonatal and suckling periods seems to be attributable to the presence of alpha-fetoprotein in serum, which binds to E2 but not to DES with high affinity. When the relative minimal dose of DES necessary for the maximal [125I]IdUrd uptake was examined in detail, the value was lower on days 10 and 20 of age than on days 30 and 40 of age. This might represent the increased sensitivity of uterine cells to oestrogen on days 10 and 20.

Aging↗

Effect of serum and 12-O-tetradecanoyl-phorbol-13-acetate on FSH-stimulated conversion of 4-androstene-3,17-dione to oestrogens in cell and organ cultures of suckling mouse ovaries.

The effect of serum and 12-O-tetradecanoylphorbol-13-acetate (TPA) on the FSH-stimulated oestrogen production was studied in both cell and organ cultures. Ovaries were removed from (WB X C57BL/6)F1 mice at 9-days of age, and the conversion of 4-androstene-3,17 -dione to oestrogens was stimulated by the addition of FSH in vitro. Either 10% serum (fetal calf, mouse, rat and horse) or 0.1 microM TPA markedly inhibited the FSH-stimulated oestrogen production by dispersed and cultured ovarian cells. In contrast, neither serum nor TPA influenced the oestrogen production in the organ culture. This suggests that the presence of tissue architecture may prevent the inhibitory effect of serum and TPA on the FSH-stimulated oestrogen production.

Androstenedione↗

Urinary retention induced by estrogen injections in mice: an analytical model.

Daily subcutaneous injections of pharmacological doses of 17 beta-estradiol (E2, 0.4 micrograms./gm. body weight) resulted in significant urinary retention in the bladder of castrated mice. Although the urinary retention developed in both male and female mice, the increase in urethral resistance to urinary flow and the dilatation of posterior urethra were observed only in castrated male mice receiving E2. Histological changes common to male and female mice were cornification and stratification of urethral epithelium and fibrosis of connective tissues surrounding the urethra, suggesting that these changes may cause the urinary retention. Although the exact mechanism has not been defined, the urinary retention produced by the present method may be useful as a model of human disease.

Animals↗

Estrogen-induced increase in eosinophil number and peroxidase activity in uterus of genetically mast cell-deficient W/Wv mice.

The role of mast cells in induction of uterine eosinophilia was investigated by using genetically mast cell-deficient (WB X C57BL/6)F1-W/Wv (hereafter called WBB6F1-W/Wv) mice. The injection of estradiol-17 beta (0.16 micrograms/g body weight) increased the peroxidase activity and eosinophil number in the uteri of castrated WBB6F1-W/Wv and WBB6F1-+/+ mice. Since no significant differences were detectable between these two type of mice, mast cells did not seem to be essential for the estrogen-induced uterine eosinophilia, at least in mice.

Animals↗

Proliferative response of mouse submandibular gland to androgen but not to thyroid hormone.

Hormone-induced differentiation and proliferation of cells were investigated in the submandibular gland of castrated female mice, by determining the esteroprotease activity and 3H-thymidine labelling index, respectively. Injections of 5 alpha-dihydrotestosterone (4 micrograms/g body weight/day) or L-thyroxine (0.5 microgram/g body weight/day) induced a significant increase in the activity of esteroprotease, which has been shown to be localized in the convoluted tubule cells of the submandibular gland. Injections of the above-mentioned dose of 5 alpha-dihydrotestosterone for 3 days induced a 43-fold increase in the labelling index of the convoluted tubule cells, but injections of the above-mentioned dose of L-thyroxine for any duration did not induce a significant increase in the labelling index. The present result suggests that hormones which induce differentiation of cells in mouse submandibular gland do not necessarily induce cell proliferation.

Animals↗

Decrease of clonidine binding affinity to alpha 2-adrenoceptor by ADP-ribosylation of 41,000-dalton proteins in rat cerebral cortical membranes by islet-activating protein.

The IC50 value for inhibition of specific [3H]yohimbine binding to rat cerebral cortical membranes by clonidine was increased, and the Hill coefficient (nH) approached unity in the presence of 150 microM GTP. Pretreatment of membranes with islet-activating protein (IAP) in the presence of NAD caused an increase in IC50 and nH values for clonidine compared with control membranes in the absence of GTP, the addition of which was without effect. Scatchard analysis showed that the Bmax value of the high-affinity component in [3H]clonidine binding was decreased by pretreatment with IAP/NAD. GTP in a concentration range of 0.1 microM-1 mM caused a significant elevation of [3H]yohimbine binding. In IAP/NAD-pretreated membranes, however, [3H]yohimbine binding was no longer affected by GTP, although IAP/NAD significantly (p less than 0.01) increased [3H]yohimbine binding compared to control. IAP ADP-ribosylated 41,000 dalton proteins of cerebral cortical membranes. From these results, it can be suggested that inhibitory guanine nucleotide regulatory protein with Mr 41,000 couples to alpha 2-adrenoceptors to regulate binding affinity of agonists and antagonists in membranes of the rat cerebral cortex.

Adenosine Diphosphate Ribose↗

Possible involvement of inhibitory GTP binding regulatory protein in alpha 2-adrenoceptor-mediated inhibition of adenylate cyclase activity in cerebral cortical membranes of rats.

Influences of alpha 2-adrenoceptor stimulation on adenylate cyclase activity were investigated in cerebral cortical membranes of rats. Pretreatment of the membranes with islet-activating protein and NAD resulted in a significant increase in basal activity as well as in GTP- or forskolin/GTP-induced elevation of adenylate cyclase activity. Strong activation of adenylate cyclase was also caused in membranes pretreated with cholera toxin together with NAD in comparison to that in control membranes, suggesting that adenylate cyclase activity is perhaps regulated by stimulatory and inhibitory GTP binding regulatory protein existing in synaptic membranes. In addition, adrenaline (with propranolol) or clonidine significantly reduced adenylate cyclase activity stimulated by pretreatment with forskolin and GTP. The inhibitory effects of adrenaline were also observed in membranes pretreated with cholera toxin and NAD. Moreover, the inhibition by adrenaline or clonidine was completely abolished by treatment with (a) yohimbine or (b) islet-activating protein and NAD. It is suggested that alpha 2-receptor stimulation causes inhibitory influences on adenylate cyclase activity mediated by the inhibitory GTP binding regulatory protein in synaptic membranes of rat cerebral cortex.

Adenylate Cyclase Toxin↗

Effects of starvation on the ultrastructure of the mouse parathyroid gland.

Ultrastructural changes of the parathyroid glands of starved mice were examined. The parathyroid glands of the starved mice showed a decrease in the volume of Golgi complexes and storage granules and an increase in the volume of lipid droplets, and contained more heterogeneously dense bodies and multivesicular bodies compared with that of the control mice. In addition, the volume of mitochondria, cisternae of granular endoplasmic reticulum and secretory granules and the number of prosecretory granules appeared to be decreased compared to those of the control mice. Myelin-like structures were observed in the parathyroid glands of the starved mice. The results of our study provide support for the hypothesis that starvation exerts an inhibitory influence not only on the synthesis but also on release of parathyroid hormone.

Animals↗

Differentiation processes of connective tissue mast cells in living mice.

Mice of mutant genotypes were used to investigate the differentiation process of connective tissue mast cells. Mast cell precursors, which are a progeny of the multipotential hematopoietic stem cell, leave the bone marrow, migrate in the bloodstream and enter into connective tissues where they proliferate and differentiate into mast cells. A portion of morphologically identifiable mast cells may function as committed and localized mast cell precursors. When local production of mast cells is demanded, the mast cells with proliferative potentiality respond first. Further demand is met by invasion and differentiation of marrow-derived precursors.

Animals↗