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Biomedical subjects

S Nagase

Publications and source records attributed to S Nagase.

At least 37 records · Page 2Linked to original sources
PubMed2000

Cytokines and T-cell responses in superantigen-related glomerulonephritis following methicillin-resistant Staphylococcus aureus infection.

BACKGROUND: We have previously reported that 10 patients who developed glomerulonephritis (GN) in association with methicillin-resistant Staphylococcus aureus (MRSA) infection showed a marked increase in DR+CD4+ and DR+CD8+ subsets of T cells and in T cells expressing several T-cell receptor (TCR) V beta+cells, perhaps representing V beta-specific T-cell activation by MRSA-derived superantigens (Kidney Int 1995; 47: 207-216). In this study we examine cytokine levels, T-lymphocyte subsets, natural killer NK cells, memory T cells, and the expression of IL-2 receptors in order to better understand the role of bacterial superantigens and cytokines in the pathogenesis of MRSA-associated GN. METHODS: Twenty-two patients with MRSA infection who later developed GN caused by staphylococcal enterotoxin were evaluated immunologically in comparison with patients whose MRSA infection was not followed by GN (non-GN group) and normal individuals. RESULTS: Among peripheral lymphocytes, the frequency of T cells expressing several TCR V betas, especially V beta 5-family TCR, was higher in the GN group than in both the non-GN group and the normal healthy control group. GN patients also showed increased serum levels of several cytokines, including tumour necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), IL-2, IL-6, IL-8, and IL-10, which have been implicated in the onset of nephritis. Memory cells, and IL-2 receptors also were elevated in the GN group. CONCLUSION: These results suggest that T cells activated by MRSA-derived staphylococcal enterotoxins and subsequent production of cytokines may play an important role in the pathogenesis of MRSA-associated GN.

Adult↗
PubMed2000

Novel germline mutations in the PTEN tumour suppressor gene found in women with multiple cancers.

Germline mutations in PTEN can predispose people to Cowden syndrome (CS) and Bannayan-Ruvalcaba-Riley (BRR) syndrome, rare, autosomal dominantly inherited neoplastic disorders. To determine whether germline mutations in PTEN contribute to genetic predisposition to multiple primary tumours within the general population, we conducted a nested case-control study, among 32 826 members of the prospective Nurses' Health Study cohort; cases were women with more than one primary tumour at different anatomical sites. We screened all nine exons of PTEN and flanking intronic splice sites for all 103 eligible cases using SSCP and sequencing. We observed two novel germline heterozygous missense mutations in exon 5 in five of the cases; three were V119L and two were V158L. Neither mutation was observed in 115 controls free of diagnosed cancer (p = 0.02). Both mutants showed partial tumour suppressor activity when compared to wild type PTEN when transfected into a PTEN null breast cancer cell line. The phenotype was cell line specific suggesting that genetic background affects growth suppression activity of the mutants. These data provide evidence that germline mutations in PTEN may be a more frequent predisposing factor for cancers in women than previously suggested.

Breast Neoplasms↗
PubMed2000

Hemodialysis does not influence the peroxidative state already present in uremia.

Hemodialysis (HD) patients are exposed to high oxidative stress, however, the nature of this stress is still unclear. In this study, we employed a specific lipid peroxidative product, phosphatidylcholine hydroperoxide (PCOOH), and evaluated the peroxidative effect of end stage renal disease by measuring thiobarbituric acid reactive substances (TBARS) and PCOOH in both plasma and erythrocyte membrane. We also surveyed plasma TBARS and PCOOH before and after HD sessions thereby assessing oxidative stress by a single HD procedure. The plasma TBARS level of healthy controls was 2.9 +/- 0.4 nmol/ml. Those of HD patients before and after HD session were 5.1 +/- 1.4 and 3.1 +/- 0.5 nmol/ml, respectively, and the pre-HD plasma TBARS levels were significantly higher than those of controls and after HD. The plasma PCOOH concentration of patients before HD was 119.7 +/- 58.4 pmol/ml and was significantly higher than that of controls which was 88.6 +/- 14.3 pmol/ml. After HD, the plasma PCOOH level decreased to 103.2 +/- 36.0 pmol/ml, which was still significantly higher than that of controls. In erythrocytes, the PCOOH level of patients was 259.3 +/- 105.4 nmol/g RBC and was significantly higher than that of controls with 88.6 +/- 32.0 nmol/g RBC. Analyzed with respect to the cause of renal disease, the polycystic kidney disease patients showed significantly lower plasma PCOOH levels than the others. These results suggest that there is an increase of lipid peroxidation in both plasma and erythrocytes of HD patients, though this oxidative stress was not brought about by HD.

Erythrocyte Membrane↗
PubMed2000

Synthesis and Properties of an Overcrowded Silabenzene Stable at Ambient Temperature.

Solid-state, room-temperature stability for silabenzene 1 is granted by the bulky silane rendering kinetic inertness. Silabenzene 1 is synthesized in good yield from the crowded chlorosilane 2 with tert-butyllithium. The delocalized, aromatic nature of 1 was confirmed by NMR spectroscopy and the (1)J(Si-C) value, as well as calculations on an analogous silabenzene.

Journal Article↗
PubMed1999

Choice of vincristine or 6-mercaptopurine on the basis of polyamine level in tumor-bearing regions of the brain.

The effects of vincristine (VC) and 6-mercaptopurine (6-MP) on body weight, regional weights, and the contents of putrescine, spermidine, and spermine in six regions of the brain were examined in rats that had been given these drugs for 5 consecutive days. VC is recommended for management of tumors in the corpus striatum and/or hippocampus, and cortex although its efficacy is dependent on the doubling time of the tumor cells, whereas 6-MP is recommended for the management of tumors in the cortex, thalamus and/or hypothalamus, and diencephalon. VC and 6-MI are chosen for treatment of the brain tumors because they reduce polyamines which are associated with the reduction of drug-sensitive cells and an inhibition of tumor growth.

Animals↗
PubMed1999

Imaging of hydroperoxides in a rat glomerulus stimulated by puromycin aminonucleoside.

BACKGROUND: To determine the locus of the increased oxidation induced by puromycin aminonucleoside (PAN), we imaged hydroperoxides in glomeruli stimulated by PAN in vivo and in vitro. METHODS: Dichlorofluorescein diacetate (DCFH-DA) in cells makes dichlorofluorescein, a substance that fluoresces when reacted with hydroperoxides. Fluorescence was detected using a photon detection video camera connected to a microscope. Two kinds of isolated glomeruli of Wistar rats were examined. One was the glomerulus obtained from rats on the seventh day following the injection of PAN. In this case, glomeruli were incubated in a buffer containing 5 mM DCFH-DA. Another was the glomerulus collected at 30 minutes after a large amount of DCFH-DA was intravenously injected. These glomeruli were incubated with either PAN or phorbol myristate acetate (PMA) in Krebs-Henseleite bicarbonate buffer. RESULTS: The images from the glomeruli treated by PAN in vivo resemble pictures of a galaxy by telescope. When the glomeruli were treated by PAN in vitro, two localized points appeared in each glomerulus after 15 minutes of incubation with PAN, and after 75 minutes of incubation, the fluorescence spread throughout the glomerulus. When glomeruli were incubated with PMA, two points that gave a very strong fluorescence were observed in each glomerulus, but they did not spread throughout the glomeruli. In both experiments, glomeruli without stimulants did not fluoresce. CONCLUSION: Increases in hydroperoxides were observed in the glomeruli from rats made nephrotic by exposure to PAN, and were also observed in glomeruli following 15 minutes of incubation with PAN in vitro.

Animals↗
PubMed1999

Formation of guanidinosuccinic acid, a stable nitric oxide mimic, from argininosuccinic acid and nitric oxide-derived free radicals.

Guanidinosuccinic acid (GSA) is noted for its nitric oxide (NO) mimicking actions such as vasodilatation and activation of the N-methyl-D-aspartate (NMDA) receptor. We have reported that GSA is the product of argininosuccinate (ASA) and some reactive oxygen species, mainly the hydroxyl radical. We tested for GSA synthesis in the presence of NO donors. ASA (1 mM) was incubated with NOR-2, NOC-7 or 3-morpholinosydomine hydrochloride (SIN-1) at 37 degrees C. GSA was determined by HPLC using a cationic resin for separation and phenanthrenequinone as an indicator. Neither NOR-2 or NOC-7 formed GSA. SIN-1, on the other hand, generates NO and the superoxide anion which, in turn, generated peroxynitrite which was then converted to the hydroxyl radical. Incubation of ASA with SIN-1 leads, via this route, to GSA. When ASA was incubated with 1 mM SIN-1, the amount of GSA produced depended on the incubation time and the concentration of ASA. Among the tested SIN-1 concentrations, from 0.5 to 5 mM, GSA synthesis was maximum at 0.5 mM and decreased with increasing concentrations of SIN-1. Carboxy-PTIO, a NO scavenger, completely inhibited GSA synthesis. SOD, a superoxide scavenger, decreased GSA synthesis by 20%, and catalase inhibited GSA synthesis only by 12%; DMSO, a hydroxyl radical scavenger completely inhibited GSA synthesis in the presence of SIN-1. These data suggest that the hydroxyl radical derived from a combination of NO and the superoxide anion generates GSA, a stable NO mimic. Meanwhile, synthesis of GSA by NO produces reactive oxygen and activates the NMDA receptor that generates NO from GSA, suggesting a positive feed back mechanism.

Argininosuccinic Acid↗
PubMed1999

Endothelial nitric oxide synthase gene polymorphism in intron 4 affects the progression of renal failure in non-diabetic renal diseases.

BACKGROUND: Nitric oxide is a very potent regulator of intrarenal haemodynamics and is thought to be an important factor in the deterioration of renal function. Our study sought to verify the hypothesis that endothelial nitric oxide synthase (ecNOS) gene polymorphism in intron 4 might have some relevance to progression in chronic renal failure. METHODS: We studied the frequencies of gene polymorphism of ecNOS intron 4 in patients with end-stage renal disease (302 cases) and compared it with that of healthy subjects (248 cases). ecNOS genotypes were determined by the polymerase chain reaction, followed by agarose gel electrophoresis. RESULTS: Two alleles of ecNOS intron 4, labelled a and b could be detected; a has four and b has five tandem 27-bp repeats. The frequencies of ecNOS4b/b, ecNOS4b/a, ecNOS4a/a genotypes were 81.0% (201/248), 19. 0% (47/248), 0.0% (0/248) in the control group, and 74.8% (226/302), 23.5% (71/302), l.7% (5/302) in all the patients, 72.7% (168/231), 25.1% (58/231), 2.2% (5/231) in the group with end-stage renal diseases, excluding diabetic nephropathy (non-DM group), and 81.7% (58/71), 18.3% (13/71), 0.0% (0/71) in diabetic nephropathy (DM group) respectively. The frequency of the ecNOS4a (ecNOSb/a, and ecNOSa/a) in all the patients and in the non-DM group were significantly higher than that in the control group (P=0.021; P=0. 0096 respectively). In contrast, there was no significant difference in the frequencies of ecNOS genotypes between the DM group and the control group (P=0.81). CONCLUSION: Among the frequencies of ecNOS intron 4 gene polymorphism, a allele displayed a significantly higher frequency in cases with end-stage renal failure (ESRF) not caused by diabetic nephropathy. ecNOS gene polymorphism in intron 4 appears, therefore, to affect the progression of renal failure in non- diabetic renal diseases, but the same conclusion could not be drawn in diabetic nephropathy.

Adult↗
PubMed1999

The outer membrane protein I of Pseudomonas aeruginosa PAO1, a possible pollutant of dialysate in hemodialysis, induces cytokines in mouse bone marrow cells.

The finding of outer membrane protein I (OprI) of Pseudomonas aeruginosa in hemodialyzers used by patients with end-stage renal failure led us to study the possible role of OprI as cytokine inducer. However, there are few reports on the biological activity of OprI, because it is difficult to obtain highly purified OprI. In this study, we attempt to establish a procedure for the efficient purification of OprI, which does not include lipopolysaccharide, from the bacterial culture broth, not hemodialyzers, to demonstrate that OprI is a potent cytokine inducer. From bacterial culture broth (1 liter), P. aeruginosa PAO1, which was confirmed previously by the sequence coding, was separated by centrifugation, high-performance liquid chromatography, and disk electrophoresis. Mouse bone marrow cells were stimulated by purified OprI, and the supernatants of the culture were analyzed by several enzyme-linked immunosorbent assay kits. The tumor necrosis factor alpha production stimulated by purified OprI was confirmed and degraded within 24 h. Furthermore, interleukin (IL) 1alpha, IL-1beta, IL-6, and granulocyte-macrophage colony-stimulating factor were also induced by OprI despite the absence of lipopolysaccharide. We conclude that OprI has the potential to induce tumor necrosis factor alpha production in mouse bone marrow cells and that tumor necrosis factor alpha contributes to the induction of inflammatory cytokines, namely IL-1alpha, IL-1beta, IL-6, and granulocyte/macrophage colony-stimulating factor, while lipopolysaccharide has little effect on these cells. These results suggest the presence of a pathway of inflammatory signal transduction triggered by OprI. In addition, OprI is possibly one of the harmful dialysate pollutants in hemodialysis patients besides the well-known lipopolysaccharide.

Animals↗
PubMed1999

Effects of methotrexate and cyclophosphamide on polyamine levels in various tissues of rats.

The effects of methotrexate (MTX) and cyclophosphamide (CYP) on body weight, organ weight, and the concentration of putrescine, spermidine, and spermine in 14 different tissues were measured in rats that had been given these compounds for 5 consecutive days. These three polyamines in both the thymus and spleen of rats treated with MTX and CYP showed a statistically significant decrease. Further, putrescine in the seminal vesicles, kidney, liver, and small intestine of MTX-treated rats, and in the prostate, seminal vesicles, kidney, heart, liver, small intestine, and lung of CYP-treated rats, spermidine in the prostate, seminal vesicles, testis, thymus, spleen, kidney, heart, small intestine, and skeletal muscle of CYP-treated rats, and spermine in the prostate, seminal vesicles, kidney, heart, small intestine, and stomach of CYP-treated rats showed statistically significant decreases. Recognition of the significance of polyamine levels and attention to their response in anti-cancer drug therapy may have clinical implications.

Animals↗
PubMed1998

Identification of a 100-kb region of common allelic loss on chromosome bands 10q25-q26 in human endometrial cancer.

In human endometrial cancer, we have previously identified a 790-kb region of common allelic loss in chromosome bands 10q25-q26, flanked by D10S587 and D10S1723. We constructed a contig covering the entire deleted region using YACs, PACs, and BACs. Five overlapping cosmid clones derived from YAC clones completely covered the entire deleted region: its size was estimated to be no larger than 200 kb. We further performed two-color fluorescence in situ hybridization (FISH) analysis to confirm the deletion and narrowed down the deleted region to 100 kb or less; it was covered by three overlapping cosmid clones that were included in one BAC clone. Restriction endonuclease mapping identified a region in which NotI, SalI, SmaI, and Xhol were clustered, suggesting the possible existence of a CpG island.

Chromosome Banding↗
PubMed1998

Suppressive effect of low amounts of safflower and perilla oils on diethylnitrosamine-induced hepatocarcinogenesis in male F344 rats.

We have investigated the modulating effects of low amounts of dietary oils rich in polyunsaturated fatty acids (PUFA) on diethylnitrosamine (DEN)-induced hepatocarcinogenesis in male F344 rats. A total of 112 animals were divided into eight groups. Groups 1-4 were given drinking water containing 40 ppm DEN for five weeks. Groups 5-8 served as controls without DEN treatment. Groups 1 and 5 were fed a basal diet containing 5% beef tallow, Groups 2 and 6 were fed a 5% olive oil diet, Groups 3 and 7 were fed a 5% safflower oil diet, and Groups 4 and 8 were fed a 5% perilla oil diet for 21 weeks, starting 1 week before DEN exposure. Beef tallow, olive oil, safflower oil, and perilla oil are rich in saturated fatty acids, a monounsaturated fatty acid, n-6 PUFA, and n-3 PUFA, respectively. All rats were killed 20 weeks after the start of the experiment. Incidences of hepatocellular adenoma and carcinoma were 100% in DEN-treated groups, irrespective of dietary oils. Multiplicities of adenomas in Groups 3 and 4 were significantly (p < 0.05) lower than in Groups 1 and 2. Multiplicity of carcinoma in Group 3 was significantly (p < 0.05) lower than in Group 1. Mean volumes of placental glutathione S-transferase-positive foci per liver and the number of argyrophilic nucleolar organizer region proteins per nucleus in the liver tumors were significantly (p < 0.05) lower in Groups 3 and 4 than in Groups 1 and 2. ras mRNA expression in liver neoplasms was also suppressed significantly (p < 0.05) in Groups 3 and 4 compared with Groups 1 and 2. Significantly (p < 0.05) higher levels of n-6 and n-3 PUFA in the phospholipid fraction of the liver were found in Groups 3 and 4, respectively, than in the other groups. In contrast, a significantly (p < 0.05) decrease in monounsaturated fatty acid was observed in Groups 3 and 4 compared with Groups 1 and 2. These results suggest that safflower oil and perilla oil, rich in n-6 and n-3 PUFA, respectively, alter the membrane fatty acid composition of the liver and suppress the development of liver cell carcinoma in rats.

Animals↗
PubMed1998

Synthesis of creatol, a hydroxyl radical adduct of creatinine and its increase by puromycin aminonucleoside in isolated rat hepatocytes.

Creatol is a hydroxyl radical adduct of creatinine and the precursor of methylguanidine (MG), a uremic toxin. We investigate the synthesis of creatol and MG from creatinine and the effect of substances that affect the hydroxyl radical in isolated rat hepatocytes. In the presence of increasing concentrations of creatinine, rising level of creatol were found after 2 h incubation in Krebs-Henseleit bicarbonate buffer. However, further increase of creatol was not observed after 4 and 6h incubations. On the other hand, MG after 2 h incubation achieved a level of about 50% that of creatol and increased depending on both the creatinine concentration and the incubation period. DMSO, a hydroxyl radical scavenger decreased the generation of creatol and MG by about 50% at 2.5 mM and the inhibition depended on DMSO concentration. Puromycin amino-nucleoside (PAN) increased both by about 170%. These findings demonstrated that hepatocytes synthesize creatol prior to MG and are inhibited by a hydroxyl] radical scavenger. They also show that PAN increased hydroxyl radical generation in tissue cells.

Animals↗