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S Kawashima

Publications and source records attributed to S Kawashima.

At least 163 records · Page 9Linked to original sources
PubMed1997

Histological localization of advanced glycosylation end products in the progression of diabetic nephropathy.

We studied the immunohistochemical localization of advanced glycosylation end products (AGEs) in the progression of diabetic nephropathy. Fourteen NIDDM patients with diabetic nephropathy were evaluated: 2 patients with normoalbuminuria, 4 with microalbuminuria (MA) and 8 with overt proteinuria (OP). Three patients with minor glomerular abnormalities were used as nondiabetic controls. Immunoreactivity to a monoclonal anti-AGE antibody (6D12) was recognized on the internal elastic membranes of arterial walls in every diabetic group. Hyaline lesions of arterioles of the MA and OP groups demonstrated strong reactions with 6D12. A portion of the nodular and exudative lesions in glomeruli of OP group patients also revealed immunoreactivity to 6D12. No immunoreactivity to 6D12 was observed in nondiabetic control specimens. We confirm that the accumulation of AGEs began in arterial walls of the early stage and presented in glomerular lesions of the late stage of the progression of diabetic nephropathy.

Adult↗
PubMed1997

Lysophosphatidylcholine inhibits receptor-mediated Ca2+ mobilization in intact endothelial cells of rabbit aorta.

We have previously reported that lysophosphatidylcholine (LPC), which accumulates in oxidized LDL and atherosclerotic arteries, inhibits endothelium-dependent relaxation and modulates Ca2+ regulation in cultured bovine aortic endothelial cells. To test the effect of LPC on endothelium-dependent relaxation and endothelial Ca2+ regulation in intact vessels, we simultaneously measured both isometric tension and endothelial cytosolic free Ca2+ concentration ([Ca2+]i), using fura 2, in intact endothelial cells of aortic strips isolated from rabbits. In the aortic strips precontracted with phenylephrine, cumulative addition of acetylcholine (ACh) dose dependently induced endothelium-dependent relaxation, with an increase in endothelial [Ca2+]i, and positive correlation was obtained between these two parameters. LPC (2 to 20 mumol/L) inhibited both ACh (3 mumol/L)-induced endothelium-dependent relaxation and an increase in endothelial [Ca2+]i in a dose-dependent manner. On the other hand, phosphatidylcholine (20 mumol/L) affected neither ACh-induced endothelium-dependent relaxation nor an increase in endothelial [Ca2+]i. LPC had no effect on endothelium-independent relaxation and a decrease in smooth muscle [Ca2+]i induced by nitroglycerin. Thus, the inhibitory effect of LPC on endothelium-dependent relaxation is due to the inhibition of agonist-induced Ca2+ mobilization in vascular endothelial cells, which is an essential step in the synthesis of endothelium-derived relaxing factor.

Acetylcholine↗
PubMed1997

Low-dose N omega-nitro-L-arginine methyl ester treatment improves survival rate and decreases myocardial injury in a murine model of viral myocarditis induced by coxsackievirus B3.

Recent reports demonstrated the expression of inducible-type NO synthase in the heart of viral myocarditis. Since NO has multiple biological actions, a substantial amount of NO produced in the diseased heart may act either as a cytotoxic or as a cytoprotective molecule in the process of myocarditis. In the present study, we examined the effect of inhibition of NO synthesis on the mortality and the extent of myocardial injury in a murine model of coxsackievirus B3-induced myocarditis. We fed the infected mice drinking water containing a relatively low concentration (0.37 mmol/L) of N omega-nitro-L-arginine methyl ester (L-NAME) for 14 days after virus inoculation. This dose of L-NAME did not change virus titers in the heart. However, L-NAME-fed mice showed a significant reduction in mortality compared with those fed normal drinking water (nontreated mice). On the contrary, mice given a higher concentration of L-NAME (3.7 mmol/L) exhibited increased mortality. In addition, mice fed a low concentration of L-NAME showed reductions in the severity of heart failure and in the area of myocardial necrosis. Although systemic blood pressure was reduced in nontreated mice, in mice fed a low concentration of L-NAME, it was maintained at a level similar to that in uninfected control mice, L-NAME-treated mice also exhibited a reduction in the degree of inflammatory cell infiltration associated with decreased production of tissue prostaglandin E2 levels in the heart compared with nontreated mice. Therefore, NO is likely to be involved in the pathogenic mechanisms of myocardial injury and resultant cardiac dysfunction in a murine model of coxsackievirus B3-induced viral myocarditis.

Animals↗
PubMed1997

Activated RhoA stimulates c-fos gene expression in myocardial cells.

Rho regulates various cell functions, including cell morphology and motility. However, the functional role of Rho on the signaling pathway in myocardial cells (MCs) is unknown. In the present study, we attempted to explore the mode of Rho action for c-fos gene expression in MCs. Expression of the c-fos promoter/enhancer linked to the luciferase reporter gene (c-fos luciferase) was stimulated by the wild type of RhoA and the point-mutated active form of RhoA (RhoA Val14) but not the biologically inactive effector domain mutant of RhoA. Rho GDP dissociation inhibitor inhibited the action of RhoA on c-fos luciferase expression. The deletion analysis revealed that the c-fos serum response element (SRE) and the 12-O-tetradecanoylphorbol-13-acetate response element (TRE) mainly account for c-fos luciferase expression by RhoA Val14. The c-fos SRE mutant, which contains an intact binding site for the serum response factor but lacks the ternary complex factor binding site, was activated by RhoA Val14. The action of RhoA Val14 on c-fos luciferase expression was not inhibited by downregulation of protein kinase C, protein kinase C inhibitors, or tyrosine kinase inhibitors. These results indicate that activated RhoA stimulates c-fos gene expression through the c-fos SRE and TRE and that the signaling pathway from activated RhoA to the c-fos promoter/enhancer is independent of these inhibitor-sensitive pathways in MCs.

Animals↗
PubMed1997

Mastoparan-stimulated prolactin secretion in rat pituitary GH3 cells involves activation of Gq/11 proteins.

Mastoparan has been reported to induce a wide variety of cellular actions by activating GTP-binding proteins (G proteins) in various cells. Here, we demonstrate that mastoparan is able to stimulate the secretion of PRL from rat anterior pituitary tumor GH3 cells in dose- and time-dependent manners. Mastoparan had no effect on the accumulation of intracellular cAMP; however, it induced a rapid increase in the intracellular Ca2+ concentration in GH3 cells. Extracellular Ca2+ was required for mastoparan-induced PRL secretion, which was inhibited by nifedipine, an L-type Ca2+ channel blocker. Incubation of mastoparan with myo-[3H]inositol-labeled GH3 cells also resulted in the increased formation of inositol phosphates (InsPs) compared with control cells. Neomycin sulfate and U73122, both phospholipase C inhibitors, suppressed mastoparan-induced PRL secretion. Guanosine 5'-1beta-thioldiphosphate (GDPbetaS) encapsulated in GH3 cells by reversible electropermeabilization suppressed the response to mastoparan. However, pretreatment with pertussis toxin had no effect on the stimulation of PRL secretion by mastoparan, and both Mas7 (a highly active analogue of mastoparan) and Mas17 (an inactive analogue) enhanced the secretion of PRL to a similar level to that of mastoparan-induced GH3 cells. In contrast, the substance P-related peptide GPant-2A, a Gq antagonist, inhibited mastoparan-induced PRL release, whereas GPant-2, a G(i/o) antagonist, did not in electropermeabilized GH3 cells. Moreover, a specific G(q/11) antibody against the carboxyl terminus of the G(q/11) alpha-subunit blocked the stimulatory effect of mastoparan on secretion and mastoparan-stimulated InsPs production in digitonin-permeabilized GH3 cells. These results indicate that mastoparan induces the Ca2+-regulated secretion of PRL from GH3 cells by activating G(q/11) and the phospholipase C pathway.

Animals↗
PubMed1997

Contribution of hydrophobicity of nonionic detergents to membrane lipid fluidity and disopyramide uptake by rat intestinal brush-border membrane vesicles.

The contribution of hydrophobicity of different types of detergents to disopyramide uptake by rat small intestinal brush-border membrane vesicles was studied in relation to their membrane lipid fluidity and the physicochemical parameters of the detergents, i.e., hydrophile-lipophile balance (HLB). Span-, Tween-type detergents or glycerol esters at non-solubilizing concentrations (0.01-0.05% (w/v)) decreased the extent of maximum uptake of the drug in the presence of outward H(+)-gradient, but not in the absence of the gradient. The fluorescence anisotropy of the vesicles using diphenylhexatriene (DPH), as reflected by its incorporation into the membrane inner lipid layer, decreased with the addition of all detergents used. In contrast, that of the vesicles using trimethylammoniumphenyl phenylhexatriene (TMA-DPH), which reflected its incorporation into the membrane outer lipid layer, increased depending on the concentration of Tween-type detergents except for Tween 81 and Tween 85, glycerol esters (MO-500, MO-750, ML-500 and ML-750); it decreased with the addition of Span-type detergents, Tween 81 and glycerol ester (MO-310). Therefore, the membrane lipid fluidity change of the outer leaflet, rather than the inner lipophilic domain, of the membrane vesicles caused by the detergents was found to be dependent on the hydrophobicity, but not on the type of detergent. This seems to correlate with the inhibitory effects on the facilitated uptake of the drug by the membrane vesicles.

Animals↗
PubMed1997

In vitro cytotoxicity of imidazolyl-1,3,5-triazine derivatives.

We examined in vitro cytotoxic activity of imidazolyl-1,3,5-triazine derivatives using human breast cancer cell lines (MCF-7, R-27, T-47D and ZR-75-1) and murine leukemia cell line (P388). The percentage of viable cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazorium bromide (MTT) assay. Hexamethylmelamine (HMM), a 1,3,5-triazine derivative has previously been recognized as an antitumor agent effective against lung, ovarian and breast cancer, but failed to show a significant cytotoxic activity in the present study. In contrast, four imidazolyl-1,3,5-triazine derivatives, 2-(1-imidazolyl)-4,6-bis(morpholino)-1,3,5-triazine, 2-(1-imidazolyl)-4-morpholino-6-(3-thiazolidinyl)-1,3,5-triazine, 2-(4-cyano-4-phenylpiperidino)-4-(1-imidazolyl)-6-morpholino-1,3,5-triaz ine and 2-(1-imidazolyl)-4-(N-methyl-N-phenylamino)-6-morpholino-1,3,5-triazine showed cytotoxic activity for most cell lines, which was significantly greater than the activity of hydroxymethylpentamethylmelamine (HMPMM), a major metabolite of HMM.

Altretamine↗
PubMed1997

The delayed recovery of impaired endothelium-dependent vasodilatory response after hemodynamic improvement in dogs with congestive heart failure.

We investigated whether impaired endothelium-dependent vasodilatory response recovers as heart failure improves. The femoral blood flow responses to intra-arterial administration of nitroglycerin (NTG) and acetylcholine (ACh) were examined in dogs with 2-week pacing-induced chronic congestive heart failure (congestive heart failure group; CHF, n = 12). Thereafter, pacing was stopped and hemodynamic changes and femoral blood flow responses were re-examined either 1 week (recover 1 week group; Re 1W, n = 6) or 4 weeks (recover 4 weeks group; Re 4W, n = 6) after the cessation of pacing. Another group in which a pacemaker was implanted without pacing served as the control group (n = 8). In CHF, heart rate and pulmonary artery pressure increased, and echocardiography revealed increased left ventricular diastolic dimension and reduced percent fractional shortening compared with those in the control group. In Re 1W, all hemodynamic parameters returned to the basal levels and did not differ from those in the control group. Although there was no significant difference in the blood flow responses to NTG among the 4 groups, the responses to ACh in CHF were significantly reduced compared with those in the control group. Despite the recovered hemodynamics, femoral blood flow responses to ACh were still reduced in Re 1W, but they returned to the levels of the control group in Re 4W. Thus, vascular endothelial dysfunction recovers along with improvement in CHF, however, the recovery of endothelial function is delayed in comparison with improvement in cardiac function.

Acetylcholine↗
PubMed1997

[A fatal case of overwhelming postsplenectomy infection syndrome developing 10 years after splenectomy].

UNLABELLED: Splenectomized patients are likely to suffer from severe infections, such as sepsis and meningitis. This syndrome is called overwhelming postsplenectomy infection (OPSI) in Europe and America. The course is rapid, the clinical symptoms are serious, and the prognosis is very poor. We treated one adult patient with OPSI syndrome that developed 10 years after splenectomy. CASE: A 26-year-old man had undergone a splenectomy following a traffic accident 10 years previously. On January 7, 1996, he had diarrhea and nausea. On January 10, he became drowsy and presented at our hospital with multiple organ failure. He underwent hemodialysis and plasmapheresis because of acute renal failure and also received immune globulin, antibiotics and prednisolone. However, these medications were not effective. He died 7 hours later. We identified diplococcus on a blood smear, IgG 3 deficiency and a low titer of specific pneumococcal IgG 2 antibody. The autopsy findings included bilateral acute hemorrhagic necrosis of the adrenal glands (Waterhouse-Friderichsen syndrome).

Adult↗
PubMed1997

[Serum transferrin receptor level as an index of the response to erythropoietin therapy for anemia in pre-dialysis patients with chronic renal failure].

In order to reveal whether serum transferrin receptor (sTfR) can serve as an index in erythropoiesis during recombinant human erythropoietin (rHuEpo) therapy for anemia in pre-dialysis patients with chronic renal failure, we analyzed hematopoietic parameters and sTfR levels in 26 patients who were newly administered rHuEpo. sTfR was determined as sTfR transferrin complex (TRC) using the enzyme linked immunosolvent assay (ELISA) and the latex agglutination nephelometric immunoassay (LA). The therapeutic effect of rHuEpo was expressed as the change in the Ht from the start of treatment to 8 weeks later. (delta Ht). Ht, RBC and Hb levels were significantly increased at 4 and 8 weeks after initiating rHuEpo treatment. Furthermore, sTfR levels were significantly increased at 2 and 4 weeks after the start of rHuEpo treatment. Absolute changes in the sTfR level (sTfR before - sTfR after) and rates of change (absolute change/sTfR before x 100) at, 2, 4 weeks after the start of rHuEpo treatment showed a significant positive correlation with delta Ht. These results indicate that sTfR is a useful marker as an index of therapeutic effect of rHuEpo for anemia in pre-dialysis patients with chronic renal failure.

Adult↗
PubMed1997

Tubulointerstitial lesions in non-insulin dependent diabetes mellitus.

The clinical features and quantitative renal morphometry, including the index of mesangial expansion (IME), the index of arteriolar hyalinous change (IAHC), the percentage of globally sclerosed glomeruli (%GS), and interstitial volume fraction for total renal cortex (Vv int/T) of 67 Japanese non-insulin dependent diabetes mellitus (NIDDM) patients were examined. For the total subject population, Vv int/T correlated with urine protein, creatinine clearance, blood pressure, IME, IAHC and %GS, but not with duration of NIDDM. No significant difference in interstitial expansion between normo- and microalbuminuric patients was observed, and Vv int/T did not correlate with urine albumin excretion rate in those patients. However, in the area without hyalinized glomeruli and atrophic tubules, we found significant interstitial expansion and thickening of the tubular basement membrane (TBM) in patients without overt proteinuria as compared with those in the age-matched minimal change control group. This study confirmed that interstitial expansion in NIDDM progresses in parallel with glomerular and arteriolar lesions and that the expansion occurs concurrently with TBM thickening before the appearance of proteinuria.

Adult↗
PubMed1996

Amino- and carboxyl-terminal heterogeneity of beta-amyloid peptides deposited in human brain.

We aimed to determine quantitatively the fine amino- and carboxyl-terminal structure of A beta peptides deposited in human brain using a set of 12 anti-A beta antibodies that distinguish between terminal modifications including isomerization, stereoisomerization, limited proteolysis, and cyclization. Immunochemical examination of cortical blocks from aged subjects distinguished by their total plaque load and from a young Down's syndrome patient identified the major invariantly deposited species as A beta x-42 (X = 1(D-aspartate) and 3(pyroglutamate) and/or 11(pyroglutamate)). These molecular forms, presumably representing by-products of metabolic intermediates toward degradation, are similar in being resistant to major aminopeptidases. A beta 17-42 ("p3' fragment), a major secreted form of truncated A beta with high insolubility, was found to be a minor one. A possible interpretation for these observations would be that proteolysis of A beta from its amino terminus may limit the rate of A beta catabolism.

Adult↗
PubMed1996

Apoptosis induction resulting from proteasome inhibition.

Proteases are known to be involved in the apoptotic pathway. We report here that benzyloxycarbonyl (Z)-Leu-Leu-leucinal(ZLLLal), a leupeptin analogue, can induce apoptosis in MOLT-4 and L5178Y cells. ZLLLal is a cell-permeant inhibitor of proteasome. Among the protease inhibitors tested, only calpain inhibitor I (acetyl-Leu-Leu-norleucinal) and ZLLLal caused a marked induction of apoptosis in MOLT-4 cells. In contrast Z-Leu-leucinal, a specific inhibitor of calpain, did not induce apoptosis. When MOLT-4 cells were incubated in the presence of ZLLLal, p53 accumulated in the cells. These results strongly suggest that inhibition of proteasome induces p53-dependent apoptosis and that proteasome can protect cell from apoptosis.

Animals↗
PubMed1996

Molecular cloning and characterization of a novel form of neuropeptide gene as a developmentally regulated molecule.

To examine the molecular basis controlling neuronal differentiation, subtraction library construction and differential screening were used to identify cDNAs whose mRNA levels are regulated in mouse NS20Y cells by dibutyryl cyclic AMP treatment. One of them, N27K, whose mRNA increases transiently during both neuronal differentiation in NS20Y cells and development in mouse brain. The deduced amino acid sequence of N27K comprises 212 amino acid residues and is a novel form of a precursor protein for a new neuropeptide nociceptin/orphanin FQ, which we independently cloned as N23K. That is, the putative protein encoded by N27K is 25 amino acids longer than that encoded by N23K. Using an antibody against a C-terminal peptide of the N27K protein that recognizes a 27-kDa protein in Western blot analysis, a punctate structure in the perinuclear region and areas near the tip of neurites is visualized in neurally differentiating NS20Y cells. The time of maximal expression correlates with periods of neurite extension, and expression decreases as the neuritic network develops. Immunohistochemistry of tissue sections of the mouse central nervous system revealed that reactivity for the anti-N27K protein antibody can detected in early generated neurons at embryonic day 14, in virtually all immature neurons at postnatal day 1, and in subsets of neurons of discrete brain regions such as the hypothalamus and spinal cord in adults. This remarkable redistribution suggests that N27K may be involved in a process in neurite outgrowth and nervous system development.

Amino Acid Sequence↗