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Biomedical subjects

S Kitagawa

Publications and source records attributed to S Kitagawa.

At least 109 records · Page 6Linked to original sources
PubMed1997

Cholecystoparesis with diabetic autonomic neuropathy.

A 69-year-old male diabetic patient was hospitalized with pneumonia in February 1996. Abdominal ultrasonography performed as a routine examination on admission revealed marked dilatation of gallbladder with a fasting maximal size of 25.7 cm2 compared with 8.8 +/- 2.9 cm2 evaluated in 30 male healthy controls aged 67 +/- 8 years old. Four months after recovery from pneumonia, abnormal gallbladder dilatation remained unchanged (25.0 cm2), while dilatation had not been observed on an examination performed 6 years earlier (9.8 cm2). Because of accompanying neurological defects, we suppose that cholecystoparesis may be caused by progression of autonomic neuropathy in this patient with diabetes mellitus.

Aged↗
PubMed1997

Increased neutrophil respiratory burst in myeloproliferative disorders: selective enhancement of superoxide release triggered by receptor-mediated agonists and low responsiveness to in vitro cytokine stimulation.

The neutrophil superoxide (O2-)-producing capacity in 57 patients with chronic myeloproliferative disorders (MPDs) and eight patients with chronic myelomonocytic leukemia (CMML) was investigated. O2- release in neutrophils stimulated by chemotactic peptide was markedly increased in all types of chronic MPD, including chronic myelogenous leukemia in both chronic phase and blastic crisis, polycythemia vera, and essential thrombocythemia, but was normal in CMML, which is thought to be a myelodysplastic disorder rather than MPD. Increase in O2(-)-producing capacity in MPD was also observed when other receptor-mediated agonists such as interleukin-8 and concanavalin A were used, but not when phorbol ester, a direct activator of protein kinase C, was used as the triggering agonist of O2- release. Priming effects of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), and tumor necrosis factor (TNF) on chemotactic peptide-induced O2- release was observed in all patients with MPD and CMML, though fold enhancement of priming effects was much less in MPD compared with normal subjects. In addition, the priming effects of TNF were less than those of GM-CSF in 10 cases, whereas the priming effects of TNF were consistently and markedly greater than those of GM-CSF in normal subjects. Tyrosine phosphorylation of 42-kDa protein stimulated by G-CSF, GM-CSF, and TNF was observed in CML neutrophils to be identical to that in normal neutrophils. Present results indicate specific potentiation of the receptor-mediated route of signaling that is linked to the respiratory burst and downregulated responsiveness to cytokines in neutrophils in patients with all types of chronic MPD, suggesting in vivo priming of patient neutrophils via certain mechanism by cytokines or related stimuli in these hematological disorders.

Concanavalin A↗
PubMed1997

[Health care needs of the elderly in long-term care facilities and their suitable placements for care].

In order to obtain information on the elderly cared for in long-term facilities, regarding their needs and the actual services received in these facilities, and to determine which facility could provide the most suitable service, elderly in two areas, urban S area and rural N area, were surveyed. The results were as follows. (1) The proportion of elderly placed in hospitals where the suitable care placements were hospitals was 84.6% in S area, and 66.6% in N area. (2) In elderly cared for in long-term facilities, the proportion of persons where the suitable care placement was in-home care was 11.7% in S area, and 14.1% in N area. (3) Therefore estimates for the elderly that would be for at home increases by 21.1% in S area and 27.2% in N area than the estimated figures used in plan for Elderly-Health Welfare in 2,000 AD.

Aged↗
PubMed1996

Transcriptional activation of the cdc2 gene is associated with Fas-induced apoptosis of human hematopoietic cells.

Apoptosis has recently been hypothesized to be the result of aberrant cell cycle control. In this study, we have investigated the role of cell cycle-regulatory elements in Fas-induced apoptosis of hematopoietic cells. When HL-60 cells were treated with anti-Fas antibody, rapid activation of growth-associated histone H1 kinase was observed without any change in cell cycle distribution. This was accompanied by the increase in cdc2 mRNA expression and Cdc2 kinase activity. Up-regulation of cdc2 mRNA was similarly induced in BCL-2-overexpressing HL-60 subline by anti-Fas treatment independently of the appearance of apoptotic phenotypes. Fas-induced apoptosis was completely inhibited by butyrolactone I, a specific inhibitor of Cdc2 kinase. Moreover, the same phenomenon was observed during Fas-induced but not spontaneous apoptosis of postmitotic granulocytes. Finally, we have found that "Fas-responsive element" was located between nucleotides -730 and -552 of the cdc2 promoter and was responsive for transcriptional activation of the cdc2 gene during Fas-induced apoptosis. These results indicate that aberrant activation of Cdc2 is associated with Fas-induced apoptosis of hematopoietic cells, and that the mechanism of cdc2 transcription during Fas-induced apoptosis is different from that in normal cell cycle control.

Apoptosis↗
PubMed1996

Human monocyte-endothelial cell interaction induces synthesis of granulocyte-macrophage colony-stimulating factor.

BACKGROUND: Adhesion of monocytes to the endothelium is an initial step in the early stages of atherosclerosis and inflammation. Granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates a range of functional activities of monocytes, including regulation of monocyte adhesion and induction of cytokine production. We investigated in this study whether CM-CSF synthesis was induced by the direct cell-to-cell interaction between human monocytes and human umbilical vein endothelial cells (ECs). METHODS AND RESULTS: The expressions of GM-CSF mRNA and protein were analyzed by Northern blotting and ELISA, respectively. Coculture of monocytes and ECs induced the high levels of GM-CSF mRNA expression, whereas culture of ECs or monocytes alone or coculture of neutrophils with ECs induced no GM-CSF mRNA expression. A large amount of GM-CSF was secreted into the supernatant upon coculture of monocytes with ECs. The supernatant from the coculture markedly stimulated 02- release in neutrophils, and this effect was significantly inhibited by anti-GM-CSF antibody (Ab). Immunohistochemistry and in situ hybridization revealed that GM-CSF protein and mRNA were clearly detectable in both ECs and monocytes adhered to ECs but not in nonadherent monocytes. The GM-CSF production by the coculture was markedly inhibited by genistein and partially inhibited by Abs against interleukin-1 and tumor necrosis factor-alpha. CONCLUSIONS: The present results indicate that GM-CSF is produced by direct interaction between monocytes and ECs and suggest that GM-CSF produced locally by monocyte-EC adhesive interaction plays an important role in the pathogenesis of atherosclerosis and inflammation by modulating monocyte/macrophage functions in vivo.

Adult↗
PubMed1996

Up-regulation of VLA-5 expression during monocytic differentiation and its role in negative control of the survival of peripheral blood monocytes.

Interaction between fibronectin (FN) and very late activation Ag-5 (VLA-5) integrin was recently reported to be involved in apoptosis of hematopoietic cells. In an effort to clarify the physiologic role of FN in the regulation of biologic behavior of terminally differentiated hematopoietic cells, we have examined the change of VLA-5 expression during myeloid cell differentiation and its effects on monocytes and granulocytes. VLA-5 alpha mRNA was up-regulated during monocytic differentiation, but not during granulocytic differentiation of HL-60 cells. Flow cytometric and immunocytochemical analysis revealed that surface expression of VLA-5 was selectively increased upon monocytic differentiation and that it was strongly positive on peripheral blood monocytes. Susceptibility to FN-induced apoptosis was greatly increased upon monocytic differentiation, and it was almost completely abrogated by anti-VLA-5 Ab or RGD peptide. Similarly, FN could significantly enhance apoptosis of normal monocytes but not of granulocytes. Finally, we have shown that anti-FN Ab could suppress spontaneous apoptosis of normal monocytes in culture and prolong their survival. These results suggest that FN might play an important role in negative regulation of the survival of monocytes through its interaction with VLA-5, which is selectively up-regulated during monocytic differentiation.

Antibodies, Monoclonal↗
PubMed1996

Dietary cholesterol enhances impaired endothelium-dependent relaxations in aortas of salt-induced hypertensive Dahl rats.

We investigated the effect of hypercholesterolemia on the vascular reactivity of thoracic aortas isolated from hypertensive Dahl salt-sensitive (DS) rats. DS rats were fed on a low-sodium diet (control group), a low-sodium plus high-cholesterol diet (CHOL group), a high-sodium diet (NaCl group) or a high-sodium plus high-cholesterol diet (NaCl + CHOL group) for 8 weeks. Hypercholesterolemia developed in the CHOL and NaCl + CHOL groups, while hypertension developed in the NaCl and NaCl + CHOL groups, with these changes being greatest in the NaCl + CHOL group. Aortic cholesteryl ester accumulation was attenuated in the aortic rings from the NaCl and NaCl + CHOL groups, compared to the control group. The degree of attenuation in the NaCl + CHOL group was significantly greater than that in the NaCl group. Endothelium-dependent relaxations induced by the calcium ionophore A23187 were attenuated only in the NaCl + CHOL group. Endothelium-independent relaxations in response to sodium nitroprusside were slightly but significantly attenuated in the NaCl + CHOL group. The relaxations in the CHOL group were comparable to those in the control group. These findings indicate that cholesterol feeding strikingly enhances the impaired endothelium-dependent relaxations and the slightly impaired endothelium-independent relaxations in the aorta of DS rats with salt-induced hypertension, parallel to the development of hypertension, hypercholesterolemia and cholesterol deposition.

Acetylcholine↗
PubMed1996

Small intestinal metastasis from esophageal carcinoma associated with small intestinal obstruction: report of a case.

The small intestine is rarely involved with metastatic tumors from outside the abdomen, and few case reports have been documented in the literature. We describe herein what to our knowledge is the third case of a solitary metastasis from squamous cell carcinoma (SCC) of the esophagus being found in the jejunum, causing small intestinal obstruction.

Carcinoma, Squamous Cell↗
PubMed1996

Gastric antral vascular ectasia causing severe anemia.

Gastric antral vascular ectasia (GAVE) that caused continuous gastrointestinal bleeding is reported in a 76-year-old woman who had been treated with repeated blood transfusions because of severe anemia. Endoscopic examination was performed and diffuse speckled telangiectasia of the entire antrum was observed. Laboratory data showed SGOT > SGPT, decreased chE level and the increased levels of serum gastrin and ICG at 15 min. Anti-HCV antibody was positive. Image examination revealed splenomegaly. There was no family history of telangiectasia, and no telangiectasia was found in other organs. The diagnosis was established as GAVE with liver cirrhosis. Surgical resection of the distal stomach resulted in termination of the bleeding, and the cirrhotic changes of the surface of the liver were revealed at that time, providing further evidence of liver cirrhosis. Although the pathogenesis of GAVE is unknown, liver cirrhosis and hypergastrinemia are thought to be associated with the condition. Importantly, this condition is a cause of severe gastrointestinal bleeding in elderly patients.

Aged↗
PubMed1996

Successful salvage of aortoesophageal fistula caused by a fish bone.

We report saving the life of a 66-year-old woman with an aortoesophageal fistula caused by a fish bone. In this case, a hemostastic clip, which was applied to the lesion during emergency endoscopy, facilitated the subsequent diagnosis of this fistula by diagnostic imaging. Compressive hemostasis was effective in controlling preoperative bleeding.

Aged↗
PubMed1996

Monocyte-endothelial cell interaction induces expression of adhesion molecules on human umbilical cord endothelial cells.

OBJECTIVE: The adhesive interaction of monocytes and endothelial cells has been implicated as a regulatory signal in the cell activation that is involved in the pathogenesis of atherosclerosis. We investigated the effect of monocyte-endothelial cell interaction on the expression of adhesion molecules, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), in human umbilical cord vein endothelial cells (HUVECs). METHODS: ICAM-1 and VCAM-1 protein and mRNA expression were determined by cellular ELISA and Northern blot analysis, respectively. RESULTS: The addition of unstimulated human monocytes, as well as interleukin-1 beta (IL-1 beta: 25 U/ml) and tumor necrosis factor-alpha (TNF: 100 U/ml), to HUVECs rapidly induced the expression of ICAM-1 and VCAM-1 protein and mRNA in HUVECs, whereas the addition of polymorphonuclear leukocytes (PMNs) had no significant effect on their expression. The induction of ICAM-1 and VCAM-1 by the co-culture of HUVECs and monocytes was significantly, but partially, inhibited by the combination of anti-IL-1 alpha, anti-IL-1 beta and anti-TNF Abs. Actinomycin D and genistein, but not calphostin C, also significantly inhibited the co-culture-induced adhesion molecule expression. CONCLUSIONS: These results suggest that the monocyte-endothelial cell interaction induces the expression of ICAM-1 and VCAM-1 in endothelial cells partially through the production of IL-1 and TNF. These findings also suggest that the monocyte-endothelial interaction further augments their interaction through the up-regulation of endothelial adhesion molecules, as a positive feedback mechanism.

Arteriosclerosis↗
PubMed1996

Tenascin-X expression in tumor cells and fibroblasts: glucocorticoids as negative regulators in fibroblasts.

Tenascin-X has recently been shown to be a novel member of the tenascin family and its distribution is often reciprocal to that of tenascin-C in the developing mouse embryo. We have investigated the expression of tenascin-X in fibroblasts and carcinoma cells in culture. Tenascin-X protein was secreted in vitro in the conditioned media at an apparent molecular mass of approximately 450 kDa. In addition fibroblasts contained a major tenascin-X isoform of 220 kDa. On northern blots, a single major transcript with a size of approximately 13 kb was detected. No overexpression of tenascin-X protein was found in primary fibroblasts of the tenascin-C-gene knockout mice. Steroid hormone glucocorticoids, were found to downregulate tenascin-X mRNA levels and protein synthesis in fibroblasts but not carcinoma cells at physiological concentrations. None of the growth factors or cytokines examined affected the expression level of tenascin-X. As in vivo study, carcinoma cells were transplanted into nude mice. In contrast to the ubiquitous presence of tenascin-X in adult skin, expression of tenascin-X protein during tumorigenesis was found to be down-regulated considerably not only in tumor cells themselves but also in tumor stroma. These findings provide evidence that the expression of tenascin-X can be influenced by stromal-epithelial interactions. We have identified glucocorticoids as physiological inhibitors of tenascin-X and suggest that glucocorticoids may in part participate in the downregulation of tenascin-X in fibroblasts in vivo.

Animals↗
PubMed1996

Characteristics of uptake of cefroxadine by rabbit small intestinal brush border membrane vesicles.

Characteristics of transport of an oral aminocephalosporin, cefroxadine, in rabbit small intestinal brush border membrane vesicles were examined. Uptake rate of cefroxadine was saturable in the presence of an inward H+ gradient, and kinetic parameters were similar to those of cephradine. However, the uptake rate was almost linear with the concentration in the absence of an inward H+ gradient up to 5 mM. Overshoot phenomenon was observed in the presence of an inward H+ gradient at 37 degrees C, but it disappeared with decrease of temperature. The Arrhenius plot of uptake rate constant showed a break point at approximately 30 degrees C. Cefroxadine uptake was optimum in the vicinity of pH 5.5 at 37 degrees C, but the dependence on extravesicular pH disappeared at 15 degrees C. The uptake of cefroxadine in the presence of an inward H+ gradient was markedly inhibited by other aminocephalosporins such as cephalexin, but the inhibition was only slight in the absence of an inward H+ gradient. Alkyl alcohols such as n-hexyl alcohol also inhibited H(+)-coupled uptake of cefroxadine at the concentration range at which the alcohols increased the membrane fluidity, and overshoot phenomenon diminished, suggesting that H(+)-coupled transport of cefroxadine is sensitive to the alcohol-induced increase in membrane fluidity. On the other hand, the alcohols rather stimulated its uptake in the absence of an H+ gradient.

Alcohols↗
PubMed1996

Absorption of methochlorpromazine in rat small intestinal everted sac.

The absorption of methochlorpromazine in rat small intestinal everted sac was investigated. 0.22% of the drug added in mucosal fluid was transferred to serosal fluid for 30 min at 37 degrees C. The absorption of the drug was slightly inhibited by choline, and more markedly inhibited by more hydrophobic quaternary ammonium cations such as tetraethylammonium and cetyltrimethylammonium. Moderate inhibition was observed by a polyamine, spermine. The absorption rate of methochlorpromazine markedly depended on temperature. The Arrhenius plot of the apparent transfer rate constant revealed high activation energy (117 kJ/mol) for the transport. Uptake of methochlorpromazine to a small intestinal segment was also inhibited by other quaternary ammonium cations corresponding with their inhibitory effects on its transport. These results suggest that methochlorpromazine binds to the relatively hydrophobic region of small intestinal epithelial cells and transfers by passing through a high energy barrier.

Animals↗
PubMed1996

Inhibitory effects of catechol derivatives on hydrophilic free radical initiator-induced hemolysis and their interaction with hemoglobin.

The effects of pyrocatechol and its monosubstituents on the hemolysis of bovine erythrocytes induced by the hydrophilic free radical initiator, 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH), were investigated. Relatively hydrophilic derivatives such as the 4-COO- substituent (protocatechuic acid), which are almost completely ionized at physiological pH, have a more inhibitory effect than the more hydrophobic derivatives such as the 4-C(CH3)3 substituent. In the presence of relatively low concentrations of the latter derivatives, the onset of hemolysis was retarded, but the hemolysis then proceeded more rapidly and the time, at which almost complete hemolysis occurred, was almost the same as that in their absence. Regression analysis on the relationships between the inhibitory effects of the derivatives and their redox potentials and hydrophobic parameters revealed that the inhibitory activity of the catechol derivatives on AAPH-induced hemolysis was controlled by low hydrophobicity as well as electron donor activity. In the presence of relatively hydrophobic catechol derivatives, oxidation of hemoglobin was observed. These findings suggest that interaction of these derivatives with hemoglobin after their penetration erythrocytes reduced the scavenging activity against free radicals. Their interaction with membrane or cytoplasmic components may cause the increased hemolysis rate after the onset of hemolysis at relatively low concentrations.

Amidines↗
PubMed1996

Activation of human monocyte functions by tumor necrosis factor: rapid priming for enhanced release of superoxide and erythrophagocytosis, but no direct triggering of superoxide release.

Tumor necrosis factor (TNF), like granulocyte-macrophage colony-stimul ating factor (GM-CSF), rapidly primed human monocytes for enhanced release of superoxide (O-2) stimulated by receptor-mediated agonists, N-formyl-methionyl-leucyl-phenylalanine (FMLP) and concanavalin A (Con A), but not by phorbol myristate acetate (PMA), which bypasses the receptors to stimulate the cells. The optimal priming was obtained by pretreatment of suspended monocytes with 10 U/mL TNF for 10 minutes at 37 degrees C. The potency of the maximal priming effect was TNF> GM-CSF, and the combined effect of TNF and GM-CSF was greater than that of each cytokine alone. GM-CSF induced an increase in cytoplasmic pH but TNF did not. These findings suggest that TNF and GM-CSF activate monocytes through different mechanisms. TNF and GM-CSF by themselves never triggered O-2 release in suspended monocytes or monocytes adherent to endothelial cells, although both cytokines triggered massive release of O-2 in human neutrophils. In additions, TNF and GM-CSF induced tyrosine phosphorylation of a 42-kD protein in neutrophils but not in monocytes. These findings suggest that the TNF-receptor- or GM-CSF-receptor-mediated signaling pathways for triggering O-(2) release is active in neutrophils but inactive or defective in monocytes. TNF also enhanced phagocytosis of sialidase-treated autologous erythrocytes by monocytes, and this effect was further potentiated in the presence of autologous fresh serum. The significant enhancement of erythrophagocytosis was obtained at 1 U/mL TNF. At this concentration of TNF, the expression of C3bi-receptor (CD11b/CD18) was upregulated. These findings show that TNF rapidly primes human monocytes for enhanced release of O-(2) and erythrophagocytosis and suggest that TNF activates monocytes through autocrine or paracrine mechanisms at the inflammatory sites inasmuch as TNF is primarily produced by activated monocytes/macrophages.

Adult↗
PubMed1996

Activation and priming of human monocytes by monocyte chemotactic activating factor: cooperation with other inflammatory cytokines and close association between an increase in cytoplasmic free Ca2+ and intracellular acidification.

Both monocyte chemotactic and activating factor (MCAF) and N-formyl-methionyl-leucyl-phenylalanine (FMLP) stimulated an increase in cytoplasmic free Ca2+ ([Ca2+]i) and changes in intracellular pH (pHi) in human monocytes in parallel at lower concentrations and stimulated superoxide (O2-) release and changes in transmembrane potential in parallel at higher concentrations. The changes in pHi were characterized by initial rapid acidification followed by sustained alkalinization, and the changes in transmembrane potential were characterized by initial depolarization followed by partial repolarization. The time courses of all responses stimulated by MCAF and FMLP were similar to each other, although the magnitude of all responses was less in MCAF-stimulated cells. MCAF by itself was a very weak stimulus for inducing O2- release. However, MCAF primed monocytes and enhanced O2- release stimulated by FMLP. The priming effect of MCAF was maximal within 5 minutes of preincubation, and the dose-response curves for priming were identical to those for triggering of an increase in [Ca2+]i. Treatment of monocytes with the intracellular Ca2+ chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), abolished not only the increase in [Ca2+]i but also the changes in pHi (both acidification and alkalinization) induced by MCAF or FMLP. MCAF further potentiated FMLP-induced O2- release in tumor necrosis factor (TNF)-, granulocyte-macrophage colony-stimulating factor (GM-CSF)-, or IL-3-primed monocytes. These findings suggest that MCAF, alone or in concert with other cytokines, primes monocytes for enhanced release of 02-, and that MCAF- or FMLP-induced intracellular acidification and alkalinization are closely associated with an increase in [Ca2+]i, but not O2- release.

Adult↗