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Biomedical subjects

S Kitagawa

Publications and source records attributed to S Kitagawa.

At least 127 records · Page 7Linked to original sources

[Evaluative indicators for the pre-hospital care system].

Survival factors for out-of-hospital cardiac arrest treated by 80 emergency/critical care centers in Japan were studied. As a result, the following three indicators to evaluate the prehospital care system are proposed. 1) Bystander initiated resuscitation at the scene of collapse 2) Defibrillation by emergency medical technicians 3) Referral system by regional hospitals to emergency/critical care centers These indicators are especially important now, when emergency medical technician services are being expanded in all areas. Also accurate diagnosis of death cause in DOA is important from the sudden death prevention standpoint.

Adolescent↗

Biosynthesis of the so-called "a" and "asialo" pathway glycosphingolipids is differentially regulated in murine myelogenous leukemia NFS60 cells.

Regulation of "a" and "asialo" series ganglioside biosynthesis was analyzed. COS-1 cells expressing only GD1a showed high synthetic activities of GM3, GM2, GM1a, and GD1a, but little activity for GA2 synthesis. However, IL-3-dependent murine NFS60-I7, which has GM1b and GD1 alpha, exhibited high synthetic activities of GM2, GM1a, and GD1a, but GM3 synthase was only 1/6 of COS-1 and GA2 synthetic activity was low. By contrast, IL-3 gene-transfected subline NFS60-H7 expressing GD1a in addition to GM1b and GD1 alpha displayed up-regulated GM3 synthase and GA2 synthase activities, while GM2, GM1a, and GD1a synthase activities were in the same levels as in NFS60-I7 cells. Since GA2 synthetic activities were not parallel with GM2 synthase in the investigated machinery of ganglioside biosynthesis, it is strongly suggested that biosynthesis of "a" and "asialo" series gangliosides is regulated differentially from each other in murine NFS60 cell lines.

Animals↗

Tyrosine phosphorylation of vav protooncogene product in primary human myelogenous leukemic cells stimulated by granulocyte colony-stimulating factor.

Granulocyte colony-stimulating factor(G-CSF), but not granulocyte-macrophage CSF(GM-CSF), induced tyrosine phosphorylation of 95-kDa protein in 13 cases of primary human acute myelogenous leukemic cells. Electrophoretic mobility of 95-kDa phosphoprotein and the protooncogene product p95vav was identical. In addition, p95vav was tyrosine-phosphorylated only in G-CSF-stimulated cells. In contrast to primary leukemic cells, amount of p95vav was under detectable level and G-CSF did not induce tyrosine phosphorylation of 90-100-kDa proteins in human neutrophils. These results indicate specific involvement of vav product in signaling pathway of G-CSF in primary human leukemic cells.

Amino Acid Sequence↗

Manipulation of a single cell with microcapillary tubing based on its electrophoretic mobility.

Manipulation of a single cell of spherical shape, approximately 5-10 microns in diameter, was performed with capillary tubing and an electrostatic field. A single cell migrates with its electrophoretic mobility into capillary tubing against the flow of electroosmosis coming out of the capillary. After trapping the cell in the capillary, it is pulled out into the other microreservoir with the application of a reverse electric voltage. When we apply a negative voltage to the microreservoir itself, the cell in it can keep floating for a relatively long period due to electrostatic repulsion. The electrophoretic mobility of a single cell is also estimated.

Animals↗

Relationship of alcohol-induced changes in Mg(2+)-ATPase activity of rabbit intestinal brush border membrane with changes in fluidity of its lipid bilayer.

We examined the effects of seven n-alkyl alcohols (from n-butyl to n-undecyl alcohol), isoamyl alcohol and benzyl alcohol on the activity of membrane enzyme Mg(2+)-ATPase of the rabbit small intestinal brush border membrane. Their relationships with the changes in the fluidity of the membrane lipid bilayer were examined through studies on the fluorescence anisotropies of diphenylhexatriene (DPH) and its ionic derivatives. Good linear correlations were found both between the partition coefficients of the alcohols and their concentrations causing similar decreases in the activity of Mg(2+)-ATPase and between their partition coefficients and the alcohol-induced changes in fluorescence anisotropies. Within the concentration range of the alcohols tested, including isoamyl alcohol and benzyl alcohol, the decreases in activity of the membrane enzyme Mg(2+)-ATPase clearly corresponded with the decreases in fluorescence anisotropy of DPH, which is thought to be located within the hydrophobic core of the membrane. From these findings, one possible explanation is that inhibition of this enzyme by the alcohols is due to perturbation of the lipid bilayer of the brush border membrane.

Adenosine Triphosphatases↗

Natural history of minute sessile colonic adenomas based on radiographic findings. Is endoscopic removal of every colonic adenoma necessary?

PURPOSE: With the development of colonoscopy and double-contrast barium enema, detection of minute sessile colonic adenomas has increased. We evaluated progression of these lesions radiologically and attempted to clarify the natural history. METHODS: A total of 125 minute sessile adenomas (< or = 5 mm in size) with histologic confirmation were examined by double-contrast barium enema at an interval of more than one year. The average follow-up period was 24 (range, 12-36; standard deviation, 9.4) months. To allow for differences in magnification, adenomas increasing in size by 2 mm or more were defined as growing, and the other lesions were defined as unchanged. RESULTS: Eighty-six adenomas showed no interval change in size. Four adenomas decreased 1 mm in size, and 27 adenomas increased 1 mm in size. The remaining eight adenomas (6 percent) increased by 2 or 3 mm in size. None of the adenomas showed any morphologic changes. There was also no difference in degree of histologic atypia between growing and unchanged adenomas. None of the adenomas developed into carcinomas during the follow-up period. CONCLUSIONS: These data show that most minute sessile adenomas remain unchanged in size and morphology over the long term. Accordingly, these adenomas probably should be followed up radiologically or endoscopically to avoid excessive polypectomy.

Adenoma↗

Relative allergenicity of cow's milk and cow's milk-based formulas in an animal model.

Human infants fed cow's milk or cow's milk-based formula may become intolerant to milk proteins partially because of allergic reactions. However, the relative allergenicity of these diets has not been clearly determined at the intestinal level. In this study, the allergenicity of cow's milk and milk-based formula was evaluated by examining intestinal anaphylaxis caused by challenge with a milk protein fraction, beta-lactoglobulin (beta LG), in guinea pigs orally sensitized to these diets. Colonic segments were removed and challenged with beta LG. An antigen-induced, anaphylactically mediated elevation of transmural short circuit current, which is caused by net chloride (Cl-) secretion, was measured in Ussing chambers as an index of local immune responsiveness. After removal of the colon, all guinea pigs were challenged by intracardiac injection with beta LG to examine the onset of bronchospasm, a test for systemic anaphylaxis. Whereas colonic segments from all guinea pigs fed whole cow's milk responded to challenge with beta LG, segments from only 60% of animals fed cow's milk formula responded to the challenge. In addition, the responders in the latter group had a significantly lower magnitude of beta LG-induced Cl- secretion compared with animals sensitized to whole cow's milk. In parallel, bronchospasm developed in all guinea pigs fed whole cow's milk. In the group of animals fed cow's milk formula, bronchospasm developed only in those who responded to the intestinal challenge. On the basis of these results, cow's milk-based formula has less sensitizing power than whole cow's milk in our animal model, and our approach is effective in testing allergenicity at the intestinal level.

Allergens↗

Preferential production of interleukin-1 beta over interleukin-1 receptor antagonist contributes to proliferation and suppression of apoptosis in leukemic cells.

Normal human monocytes were isolated in a nascent state by centrifugal elutriation and used for the study of interleukin-1 (IL-1) and interleukin-1 receptor antagonist (IL-1ra) expression. Neither IL-1 beta nor IL-1ra mRNA was present in monocytes just after the isolation, but they were induced simultaneously in response to various stimulants. In contrast, only IL-1 beta mRNA was expressed in monocytic leukemia cell line JOSK-1, while little or no IL-1ra mRNA was detected even after stimulation. Dominant expression of IL-1 beta over IL-1ra was also observed in fresh leukemia cells including monocytic leukemias, i.e., IL-1 beta mRNA was constitutively expressed in 26 out of 36 cases (72.2%), whereas IL-1ra mRNA was present only in 8 cases (22.2%). The signal intensity of IL-1 beta mRNA was stronger than that of IL-1ra even in IL-1ra-positive cases. Apoptotic cell death of monocytes was significantly inhibited by IL-1 beta, and it was enhanced by IL-1ra. In fresh leukemia cells, 3H-thymidine uptake was generally higher in IL-1-producing cases than in IL-1ra-producing cases, and was increased by the addition of IL-1 beta in all cases tested. Cell proliferation was inhibited by either IL-1ra or anti-IL-1 beta antibody in IL-1-producing cases, while it was enhanced by anti-IL-1ra antibody in IL-1ra-producing cases. These results suggest that the balance between IL-1 and IL-1ra is necessary for homeostasis of the mononuclear phagocytosis system. The imbalance between these two counter-acting cytokines might contribute to the altered growth and accumulation of leukemic cells.

Apoptosis↗

Over-expression and amplification of the CDC2 gene in leukaemia cells.

The expression and structure of the cdc2 gene, one of the master regulators of the eukaryotic cell cycle, were investigated in fresh leukaemic cells from 51 cases of various types of leukaemia. Cdc2 mRNA transcripts were detectable in approximately 40% (21/51) of cases by Northern blotting. Over-expression of cdc2 mRNA as compared to normal bone marrow cells was noted in 10/21 cases with detectable cdc2 mRNA transcripts. Amplification of the cdc2 gene was found in three cases. Cdc2 mRNA was over-expressed in these three cases, suggesting that gene amplification is a direct cause of mRNA over-expression in a subset of cases. Cell proliferative capacity was well correlated with the amount of cdc2 mRNA transcripts, i.e. 3H-thymidine incorporation was highest in cases with cdc2 mRNA over-expression and was significantly higher in cdc2-positive cases than in cdc2-negative cases. These results suggest that over-expression of CDC2, which is due to the gene amplification in some cases, might play a role in altered growth of leukaemic cells.

Blotting, Northern↗

Transformation into acute basophilic leukaemia in a patient with myelodysplastic syndrome.

We describe a patient with basophilic leukaemia following a 2-year period with myelodysplastic syndrome (refractory anaemia). The marrow showed 59.4% of blasts with 25.0% of mature and immature basophils. The leukaemic blasts contained granules, positively stained with toluidine blue but negative for peroxidase. The basophilic differentiation was confirmed by ultrastructural analysis demonstrating immature basophil granules. In addition, a morphological transition from immature blasts to more mature basophils was observed. Immunophenotypic analysis of blasts and basophils showed positive for CD5, CD7, CD13, CD33 and CD34. Cytogenetic investigation showed an abnormal karyotype, 46,XY,del(5)(q31q35), in 11% of the cells examined when the initial diagnosis of refractory anaemia was made. However, expansion of the same clone up to 100% was observed concomitantly with transformation to basophilic leukaemia.

Anemia, Refractory↗

Different cholesterol deposition in aorta of Dahl salt-sensitive rats and spontaneously hypertensive rats fed a high-cholesterol diet.

1. We compared the serum and aortic lipid levels in spontaneously hypertensive rats (SHR) and Dahl salt-sensitive rats (DSR) fed a high-cholesterol (HC) diet. 2. In SHR fed the HC diet, the serum cholesterol level significantly increased, but no aortic cholesterol deposition was observed. 3. The serum cholesterol level in DSR fed the HC diet markedly increased compared to that in DSR fed the basal diet, and this change was greater with the diet containing 8% NaCl than 0.4% NaCl. A significant increase in the content of aortic cholesterol, notably cholesteryl ester, was observed in only DSR fed the HC diet containing 8% NaCl. 4. These results suggest that the combination of hypercholesterolaemia with salt-induced hypertension acts as a greater risk factor for atherosclerosis than that with genetic hypertension.

Animals↗

Comparison of the effects of hypercholesterolaemia on relaxation responses in aortas of spontaneously hypertensive rats and Dahl salt-sensitive rats.

1. We investigated the effects of hypercholesterolaemia on relaxation responses in thoracic aortas isolated from two different types of hypertensive rats; spontaneously hypertensive rats (SHR) and Dahl salt-sensitive rats (DSR). 2. All rats fed the high cholesterol diet for 8 weeks showed a significant increase in the serum cholesterol level. The high cholesterol diet did not change the blood pressure of SHR, but increased that of hypertensive DSR fed a high-salt diet. 3. In aortas of SHR, the high-cholesterol diet did not change the endothelium-dependent and -independent relaxation induced by acetylcholine (ACh) and sodium nitroprusside (SNP), respectively. 4. In aortas of hypertensive DSR, the high-cholesterol diet notably reduced the ACh-induced relaxations and slightly reduced SNP-induced relaxation. 5. These results suggest that hypercholesterolaemia causes greater impairment of endothelium-dependent relaxation in rat aorta with salt-induced hypertension than genetic hypertension.

Acetylcholine↗

Suppressive role of endogenous endothelial monocyte chemoattractant protein-1 on monocyte transendothelial migration in vitro.

Monocyte chemoattractant protein-1 (MCP-1, or monocyte chemotactic and activating factor) is thought to play an important role in monocyte infiltration into tissue, but little is known about its effect on monocyte-endothelium interaction. We examined the effect of MCP-1 produced by cytokine-activated endothelial cells (ECs) on monocyte-endothelium adhesion and subsequent transendothelial migration by using a double-chamber vessel model. Unstimulated ECs showed no MCP-1 expression, but exposure to interleukin-1 beta (IL-1 beta, 25 U/mL) induced marked MCP-1 mRNA expression and protein synthesis. When placed in the lower compartment, recombinant human (rh) MCP-1 (100 ng/mL) produced a 1.9-fold and a 2.7-fold increase in adhesion and migration, respectively, compared with a corresponding 51% and 59% decrease when placed in the upper compartment. Migration of monocytes was dependent on a gradient of rh-MCP-1 from the apical to basilar side of the EC layer. Furthermore, a forward gradient of MCP-1 induced adherent cells to increase their subsequent migration, whereas a reverse gradient induced the cells to detach and completely inhibited their subsequent migration. Pretreatment with IL-1 beta for 4 and 24 hours produced a 20% and 63% increase in monocyte migration, respectively. In the presence of anti-MCP-1 antibody, the increase was further enhanced by 52% and 152%, respectively. These results suggest that endogenous endothelial MCP-1, when secreted by IL-1-stimulated ECs, suppresses monocyte migration in the presence of MCP-1 on the basilar side of the EC layer.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies↗