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N Sato

Publications and source records attributed to N Sato.

At least 235 records · Page 13Linked to original sources
PubMed2000

Novel biphasic effect of pyrrolidine dithiocarbamate on neuronal cell viability is mediated by the differential regulation of intracellular zinc and copper ion levels, NF-kappaB, and MAP kinases.

Nuclear factor kappaB (NF-kappaB) is a transcription factor involved in the expression of a wide range of genes, most of which code for proteins that play a role in immunity and inflammation. Pyrrolidine dithiocarbamate (PDTC) is a well-known inhibitor of NF-kappaB. Although its mechanism of action is conferred by its antioxidant property, other mechanisms by which PDTC can act as a prooxidant, metal chelator, and free thiol group modulator have recently been suggested. Here we report that PDTC caused a dual effect on cell viability in neuronal rat pheochromocytoma (PC12) cells, depending on its concentration. Increase of intracellular zinc and copper ion levels selectively potentiated the cytotoxic PDTC effect in a dose-dependent manner, and thiol reagents, such as glutathione and N-acetylcysteine, as well as divalent metal-chelating reagents, such as EDTA and bathocuproline disulfonic acid, blocked its cell death effect. The differential effect of PDTC on cell viability correlates well with the inhibition of NF-kappaB activities. In addition, PDTC differentially activated microtubule-associated protein (MAP) kinases, such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), but not p38, depending on its dose, and the coaddition of glutathione (GSH), other antioxidants, and metal ions also modulated their activities. Furthermore, stable Bcl-2 expression blocked the PDTC-induced cell death. These results suggest that the thiol groups and free zinc and copper ion levels are important for the novel biphasic PDTC effect on cell viability, which is associated with the differential activation of NF-kappaB and MAP kinases.

Animals↗
PubMed2000

Centrosome abnormalities in human carcinomas of the gallbladder and intrahepatic and extrahepatic bile ducts.

During mitosis, 2 centrosomes ensure accurate assembly of bipolar spindles and fidelity of the chromosomal segregation. The presence of more than 2 copies of centrosomes during mitosis can result in the formation of multipolar spindles, unbalanced chromosome segregation, and aneuploidy. Recent studies have provided evidence that centrosome hyperamplification plays a pivotal role in carcinogenesis. Using immunofluorescence analysis with gamma-tubulin and pericentrin antibodies, paraffin-embedded sections from 40 malignant biliary diseases including gallbladder cancers (GC; n = 13), intrahepatic cholangiocellular carcinoma (CCC; n = 19), and extrahepatic bile duct cancers (BDC; n = 8) were examined. Thirty-seven benign biliary diseases including chronic cholecystitis, gallbladder adenoma, hepatolithiasis, and choledochal cyst were included as benign controls. The frequencies of the centrosome abnormalities were 70% for GC, 58% for CCC, and 50% for BDC, respectively. The frequencies of centrosome abnormalities in malignant biliary diseases were significantly higher than in their benign counterparts (GC, CCC, BDC; P =.001,.002, and.001, respectively). The results of current study also indicated that biliary malignancy in the advanced stage (III-IV) displayed a higher frequency of centrosome abnormalities than in the early stage (I-II) (P <.001). We conclude that abnormalities in size, number, and shape of the centrosome are frequently observed in biliary tract malignancy. Centrosome abnormalities started to occur in the early stage of biliary malignancy and became very frequent in the advanced stage. This implies that centrosome abnormality might relate to the transition from early to advanced malignancy in biliary malignancy.

Adenocarcinoma↗
PubMed2000

Estrogen is involved in early alcohol-induced liver injury in a rat enteral feeding model.

The aim of this study was to investigate whether reduction in blood estrogen by removal of the ovaries would decrease the sensitivity of female rats to early alcohol-induced liver injury using an enteral ethanol feeding model, and if so, whether estrogen replacement would compensate. Livers from ovariectomized rats with or without estrogen replacement after 4 weeks of continuous ethanol exposure were compared with nonovariectomized rats in the presence or absence of ethanol. Ethanol increased serum alanine transaminase (ALT) levels from 30 +/- 6 to 64 +/- 7 U/L. This effect was blocked by ovariectomy (31 +/- 7) and totally reversed by estrogen replacement (110 +/- 23). Ethanol increased liver weight and fat accumulation, an effect that was minimized by ovariectomy and reversed partially by estrogen replacement. Infiltrating leukocytes were increased 6. 7-fold by ethanol, an effect that was blunted significantly by ovariectomy and reversed by estrogen replacement. Likewise, a similar pattern of changes was observed in the number of necrotic hepatocytes. Blood endotoxin and hepatic levels of CD14 messenger RNA (mRNA) and protein were increased by ethanol. This effect was blocked in ovariectomized rats and elevated by estrogen replacement. Moreover, Kupffer cells isolated from ethanol-treated rats with estrogen replacement produced more tumor necrosis factor alpha (TNF-alpha) than those from control and ovariectomized rats. It is concluded, therefore, that the sensitivity of rat liver to alcohol-induced injury is directly related to estrogen, which increases endotoxin in the blood and CD14 expression in the liver, leading to increased TNF-alpha production.

Alanine Transaminase↗
PubMed2000

Overgrowth and translocation of Escherichia coli from intestine during prolonged enteral feeding in rats.

Our objective was to examine changes in bacterial flora in the gastrointestinal tract that might lead to their translocation during the prolonged enteral administration of an elemental liquid diet. Eleven rats (experimental group) received a feeding gastrostomy and were administered an intragastric infusion of a liquid elemental diet for 17 days, while 9 rats (control group) received chow and water ad libitum for 17 days. The animals were then killed and the mesenteric lymph nodes (MLNs), liver, jejunum, ileum, and cecum were aseptically removed, homogenized, and cultured for isolation of bacteria. A statistically significant increase in the population of a single species of Enterobacteriaceae, Escherichia coli, was observed in the ileum and cecum of the experimental group fed the liquid diet as compared with the control group. Five of the MLNs from the 11 experimental rats (45%) were positive for E. coli, as compared with none from the 9 control rats, a statistically significant difference (P = 0.038). The E. coli isolated from the MLNs and the ileum of the experimental group exhibited the O168:H serotype. Our results suggest that E. coli isolated from the MLNs of the experimental group had translocated from the intestine. The animal model described here may be useful in screening for drugs to reduce the problem of translocation of intestinal bacteria.

Animals↗
PubMed2000

Combined modality therapy including surgery for stage III small-cell lung cancer on the basis of the sensitivity assay in vitro.

Fifty-nine consecutive patients with clinical stage (cStage) I-III resectable small-cell lung cancer (SCLC) underwent surgery with adjuvant chemotherapy based on an in vitro sensitivity assay between April 1982 and March 1992. In 42 (71%) of these patients, a stable passage of cancer cells from resected specimens was possible and the sensitivity of these cultured SCLC cells to anticancer drugs was examined by the MTT method. In the sensitivity assay, vincristine (VCR) showed the most intense specific efficacy for SCLC, followed by cyclophosphamide (CPM) and cisplatin (CDDP). The 5-year survival rates for pathological stage (pStage) I, pStage II, and pStage III were 55%, 33%, and 23%, respectively. The 5-year survival of the patients with pStage III operated on in the first 5 years was 7% (1/14). On the other hand, 6 of the 16 pStage III patients (38%) operated on during the second 5-year period, who were generally treated with pre- and postoperative adjuvant chemotherapy combined with three drugs, survived over 5 years. In conclusion, these results suggest that combined modality therapy including surgery is necessary, and adjuvant chemotherapy combined with VCR, CPM, and CDDP may be useful in the treatment of Stage III SCLC disease, for the purpose of achieving a long-term survival with both a good performance status and quality of life for the patients.

Adult↗
PubMed2000

Human CD8 and CD4 T cell epitopes of epithelial cancer antigens.

Recent human tumor immunology research has identified several genes coding immunogenic peptides recognized by CD8 cytotoxic T lymphocytes (CTLs) in melanoma tumors. Very recently, CD4 T cell antigenic epitopes were also determined in certain melanoma tumors. The use of these peptides in conjunction with human immunotherapy could prove to be of great benefit. However, such peptides in clinically common tumors of epithelial cell origin, such as of the stomach, colon, lung, etc., have not yet been determined extensively. We describe for the first time an HLA-A31 (A*31012)-restricted natural antigenic peptide recognized by the CD8 CTL TcHST-2 of gastric signet ring cell carcinoma cell line HST-2. We also identified the HLA-DRB1*08032-restricted peptide recognized by the CD4 T cell line TcOSC-20 of squamous cell carcinoma OSC-20 derived from the oral cavity. The antigenic peptide of HST-2, designated F4.2, is composed of 10 amino acid residues with two anchor motif residues necessary for binding to HLA-A31 molecules. The synthetic F4.2 peptide enhanced the reactivity of TcHST-2 against HST-2 cells. Furthermore, introduction of an expression minigene coding F4.2 peptide to HLA-A31(+) cells conferred cytotoxic susceptibility to TcHST-2 on the cells. Some stomach cancer lines into which the HLA-A31 gene had been introduced, such as MKN28-A31-2, were lysed by TcHST-2, suggesting the presence of F4.2 peptide in at least some HLA-A31(+) stomach cancers. Furthermore, F4.2 peptide induced an F4.2 peptide-specific CTL response in at least 30-40% of HLA-A31(+) peripheral blood lymphocytes from gastric cancer patients, suggesting that F4.2 peptide could be used as a cancer vaccine for gastric tumors. The natural antigenic peptide of OSC-20 was also determined using acid extraction and biochemical separation and by mass spectrometry. Consequently, OSC-20 peptide was designated as the 6-1-5 peptide, an HLA-DRB1*08032-restricted 16-mer peptide with two possible anchor motifs. It has an amino acid sequence identical to that of human alpha-enolase, suggesting that it was derived from the processed parental alpha-enolase protein. We are presently attempting to determine the genes that code tumor rejection antigens recognized by HLA-A24- and A26-restricted T cells, including those of pulmonary and pancreatic carcinomas. The search for these antigenic peptides may lead to the identification of immunogenic peptide antigens that would be suitable for clinical use in commonly occurring epithelial cancers.

Amino Acid Sequence↗
PubMed2000

Monoclonal antibody-dendrimer conjugates enable radiolabeling of antibody with markedly high specific activity with minimal loss of immunoreactivity.

For the purpose of radioimmunotherapy, labelling of monoclonal antibody with high specific activity is often necessary, especially when using a radionuclide with a shorter half-life. Polyamine dendrimers (PAMAM) are novel synthetic polymeric molecules with large numbers of amine residues on their spherical surface. In order to bind large numbers of radiometals to single antibody molecules, the generation-4 PAMAM (G4), which has 64 amines, was conjugated with 43 molecules of 2-(p-isothiocyanatobenzyl)-6-methyl-diethylene triamine penta-acetic acid (1B4M), a derivative of DTPA. This product [G4-(1B4M)43] was then conjugated with OST7, a murine monoclonal IgG1. We evaluated the achievable specific activity for 111In labeling, immunoreactivity, biodistribution, and tumor targeting in mice of the 111In- or 153Gd-OST7-G4-(1B4M)43 as compared with radiolabeled OST7-1B4M or 56C-1B4M. The maximum specific activity of 111In-OST7-G4-(1B4M)43 and 111In-OST7-1B4M was 470 and 8.7 GBq/mg (12,700 and 263 mCi/mg), respectively. Immunoreactivity of radiolabeled OST7-G4-(1B4M)43 and OST7-1B4M, as determined by the binding to KT005 cells expressing the antigen, was respectively 91% and 84% of that of 125I-labelled OST7. Biodistribution studies for preparations with maximum specific activity in normal mice 3 h after injection showed that 111In- or 153Gd-OST7-G4-(1B4M)43 cleared faster from the blood and accumulated more in the liver than did 111In- or 153Gd-OST7-1B4M. The dendrimer 1B4M [G4-(1B4M)64] itself showed similar saturation effects with metals. The radioactivity in all the other organs reflected the rapid clearance of radioactivity from the blood. 153Gd-OST7-G4-(1B4M)43 showed specific accumulation in the KT005 tumor. In conclusion, we could successfully bind 49 times as many metal atoms to an antibody molecule as is possible with conventional metal labeling for indium and gadolinium, and did so with minimal loss of immunoreactivity. When we achieved radiolabeling with maximum specific activity, Gd conjugate showed better biodistribution than In conjugate.

Animals↗
PubMed2000

A model of binocular stereopsis including a global consistency constraint.

The binocular correspondence problem was solved by implementing the uniqueness constraint and the continuity constraint, as proposed by Marr and Poggio [Marr D, PoggioT (1976) Science 194: 283-287]. However, these constraints are not sufficient to define the proper correspondence uniquely. With these constraints, random-dot stereograms (RDSs), consisting of the periodic textures in each image, are treated as a correspondence of surfaces composed of patches of alternating values of disparity. This is quite different from the surface we perceive through the RDSs, that is a surface characterized by a single depth. Because these constraints are local, they cannot produce the global optimum of correspondence. To obtain the global optimum of correspondence, we propose a model of binocular stereopsis in which a global measure of correspondence is explicitly employed. The model consists of two hierarchical systems. First, the lower system processes various correspondences based on the uniqueness constraint. Second, the higher system provides a global measure of correspondence for the disparity in question. The higher system uniquely determines the global optimum of correspondence in the lower system through the recurrent loop between hierarchical systems. The convergence of the recurrent loop is determined by the consistency between the hierarchical systems. The condition is termed the 'global consistency constraint.

Algorithms↗
PubMed2000

Effects of pneumoperitoneum on cardiac autonomic nervous activity evaluated by heart rate variability analysis during sevoflurane, isoflurane, or propofol anesthesia.

BACKGROUND: The effects of pneumoperitoneum on the activity of the cardiac autonomic nervous system have not been completely understood. METHODS: In this study, 45 unpremedicated adult patients who underwent laparoscopic cholecystectomy were anesthetized with either 3.5% sevoflurane, 2% isoflurane, or 8 mg/kg/h propofol (15 patients in each group). The status of cardiac autonomic nervous activity was evaluated by heart rate variability analysis three times: once when the patient was awake, once after induction of general anesthesia, and once after insufflation for pneumoperitoneum. Intra-abdominal pressure was maintained automatically at 10 mm Hg by a carbon dioxide (CO(2)) insufflator. For each measurement, electrocardiogram was recorded for 256 s and played back offline to detect R-R intervals. Power spectral analysis of heart rate variability was applied, and the low-frequency (LF, 0.04-0.15 Hz) and high-frequency (HF, 0.15-0. 40 Hz) bands of the spectral density of the heart rate variability were obtained from a power spectra of R-R intervals using the fast-Fourier transform algorithm. The HF/LF ratio also was analyzed. RESULTS: Measurements of heart rate variability in the three groups showed similar change. Although the power of HF, which represents parasympathetic nervous activity, did not change, the power of LF, which represents both sympathetic and parasympathetic nervous activity, decreased during the anesthetized stage and increased during the insufflated stage. The HF/LF ratio, which represents the balance of parasympathetic and sympathetic activity, increased after induction of general anesthesia, and decreased after insufflation. CONCLUSIONS: Our results suggest that pneumoperitoneum increases sympathetic cardiac activity. The choice of general anesthetic did not seem to have a major influence on the change in the cardiac autonomic nervous system after induction of pneumoperitoneum for laparoscopic cholecystectomy.

Adult↗
PubMed2000

GM-CSF gene therapy using adenoviral vector in hamster pancreatic cancer.

The aim of this study was to examine the antitumor effect of irradiated granulocyte macrophage-colony-stimulating factor (GM-CSF)-gene-transduced hamster pancreatic cancer cells and its relationship to the amount of GM-CSF produced by transduced tumor cells. Hamster pancreatic adenocarcinoma cells, HPD1NR, which spontaneously secrete 15.0+/-0.4 pg/106 cells per 24 h of GM-CSF, and HPD2NR cells, which do not secrete GM-CSF, were used. When these cells were infected with recombinant adenovirus harboring the GM-CSF gene, HPD1NR and HPD2NR secreted 624.2+/-9.9 and 157.8 +/-5.7 pg/106 cells per 24 h, respectively. Vaccination with irradiated GM-CSF-secreting HPD2NR completely protected syngeneic hamsters challenged with live parental cells. On the other hand, vaccination with irradiated HPD1NR protected 60% of hamsters from tumor development after challenge with parental cells. None of the tumor-free hamsters initially vaccinated with irradiated GM-CSF-producing HPD2NR cells developed tumor upon repeated challenge with parental cells during the entire observation period. Irradiated GM-CSF-gene-transduced hamster pancreatic cells are promising as a novel adjuvant cancer therapy after surgery for primary and metastatic pancreatic cancer. The results indicate the necessity for a therapeutic strategy for cancer based on the cytokine status of tumors.

Adenoviridae↗
PubMed2000

Taurine preserves gap junctional intercellular communication in rat hepatocytes under oxidative stress.

Gap junctional intercellular communication (GJIC) between hepatocytes is important for the maintenance of differentiated liver functions. Taurine is known to be cytoprotective, and is used clinically to improve liver functions. We evaluated the effect of taurine on GJIC in hepatocyte doublets under oxidative stress. Hepatocyte doublets were isolated from female Wistar rats, using a collagenase perfusion technique, and cultured in Leibovitz-15 medium containing fetal bovine serum (10%). H2O2 (2 mM) and/or taurine (0.1-1 mM) were added 2 h after inoculation, and the culture was incubated for 3 h. Fluorescent dye (Lucifer Yellow CH) coupling between adjacent cells was evaluated by microinjection. The distribution and quantity of connexin 32 (Cx32) in hepatocytes were detected using indirect immunofluorescence analysis and Western blotting. Steady state mRNA levels of Cx32 were detected by Northern blotting. The percentage of dye coupling 5 h after inoculation was 88 +/- 6.3% in the control. however, this was decreased to almost half the control value by H2O2. Taurine prevented the decrease caused by H2O2 in a dose-dependent manner. Immunofluorescence analysis for Cx32 demonstrated numerous punctate fluorescent spots along the intercellular plasma membrane in controls, which were significantly decreased by H2O2. Taurine prevented the decrease of Cx32. Western blot analysis also showed the decrease of Cx32 protein levels by H2O2 treatment, which decrease was prevented by taurine. Interestingly, H2O2 and/or taurine treatments did not affect Cx32 mRNA levels. Our findings indicated that H2O2 treatment decreased GJIC between hepatocytes, most likely due to augmenting the degradation of Cx32 proteins, whereas taurine prevented this process. This effect of taurine is beneficial for the preservation of differentiated functions in the liver under oxidative stress.

Animals↗
PubMed2000

Comparison of the efficacy of 400mg and 800mg of clarithromycin used with lansoprazole and amoxicillin in eradication regimens for Helicobacter pylori infection in a Japanese population.

We conducted a randomized prospective comparative study to determine whether a 1-week lansoprazole-amoxicillin-clarithromycin (LAC) regimen with 800 mg of clarithromycin a day was more effective such a regimen with 400 mg daily in the Japanese population. One hundred and seventy-five Helicobacter pylori-positive patients were randomly assigned to receive one of two different 7-day regimens, one with clarithromycin 400 mg (LAC 400 regimen) and the other with clarithromycin 800 mg (LAC 800 regimen). The cure rates for both regimens were similar, although adverse effects were significantly more frequent in the LAC 800 regimen, suggesting that 400 mg of clarithromycin may be sufficient in our patient population.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2000

Long-term survival of a poor-risk octogenarian following wedge resection under VATS for small-cell lung cancer: report of a case.

We describe herein the case of an 81-year-old man who has remained disease-free for more than 3 years after undergoing a wedge resection of cStage I small-cell lung cancer (SCLC) under video-assisted thoracoscopic surgery (VATS), with no adjunct chemotherapy or radiotherapy. The patient had compromised pulmonary function and was a poor surgical risk. As he could not have endured a conventional lobectomy or intensive chemotherapy, a nonanatomical wedge resection of the area of lung involved by the primary tumor was carried out under VATS. Cancer cells from the resected tumor were cultured and the growth characteristics and sensitivity to 12 anticancer drugs were examined. The majority of primary cultured cells proliferated in a monolayer, like paving stones, resembling the growth pattern of non-small-cell carcinoma cells in vitro. The subcultured cells were resistant to most of the drugs, but showed weak sensitivity to cisplatin (CDDP), adriamycin (ADR), and vincristine (VCR). Therefore, the patient was discharged with no adjunct postoperative therapy and was followed up at an outpatient clinic. He has remained alive and disease-free for more than 3 years. Thus, we considered that performing wedge resection under VATS for a primary tumor could be appropriate treatment for selected patients with cStage I SCLC in a peripheral region, especially if they are elderly and a poor surgical risk.

Age Factors↗
PubMed2000

The significance of surgery for bulky N2 small-cell lung cancer: a clinical and in vitro analysis of long-term survivors.

Until recently, stage III small-cell lung cancer (SCLC) has not been considered an indication for surgical treatment, however, stable subculture has become possible in about 80% of the patients with SCLC in our hospital. Therefore, we have been performing surgery for all patients with cStage I-III resectable tumors and giving combined-modality therapy based on the sensitivity assay in vitro since April 1982. In the present study, we reviewed 30 consecutive patients with cStage III and pStage III SCLC, including 27 with N2 disease who underwent surgery between 1982 and 1992, 7 of whom (23%) survived disease-free for over 5 years. We examined the cell characteristics in vitro and the actual treatment of five patients with bulky N2 lesions, four of whom were long-term survivors and one of whom died 11 months after surgery, as controls for comparison with the long-term survivors. Based on the results of the cell characteristics in vitro, SCLC was determined to be a heterogeneous tumor. Thus, surgical excision of the primary tumor with adjuvant therapy might be necessary to achieve long-term survival and maintain good performance status, and to improve quality of life in patients with bulky N2 SCLC by eliminating drug-resistant tumor cells within the primary tumor.

Aged↗
PubMed2000

Nonoperative treatment of reperforated duodenal ulcer: report of three cases.

During the period between 1983 and 1998, a total of 58 patients were admitted to the surgical department of Akita Red Cross Hospital with acute duodenal perforation. Of these 58 patients, 16 were treated operatively and 42 were treated nonoperatively. Among the 38 men and 4 women who received nonoperative treatment, 3 developed reperforation. The incidence of reperforation was 7.1% and the mean average interval from the initial treatment until reperforation was 3.5 years. Endoscopic biopsy and/or serum anti-H. pylori IgG measurement revealed Helicobacter pylori infection in all three patients. No serious complications developed during the nonoperative treatment of reperforation in these three patients, and their recovery was uneventful. The hospital stay ranged from 10 to 18 days, with a mean stay of 12 days after the first perforation and from 14 to 18 days, with a mean stay of 15.6 days after the reperforation. Nonoperative treatment proved successful as a life-saving procedure for reperforation of a duodenal ulcer in all three patients.

Adult↗
PubMed2000

Long-term survival of a patient with stage IV pulmonary large cell carcinoma achieved by combined-modality therapy: report of a case.

We describe herein the case of a 59-year-old-man with stage IV pulmonary large cell carcinoma and a giant brain metastasis, in whom two sublines with different growth characteristics and drug sensitivities in vitro were established from the primary tumor. Disease-free survival for more than 5 years after surgery was achieved by combined-modality therapy together with surgery to remove the primary tumor, radiation to the brain metastasis, and chemotherapy to presumed hematogenous dissemination. Subline 1 proliferated in a monolayer of epithelial-like cells, while subline 2 showed a floating colony pattern of proliferation, resembling the typical growth characteristics of small cell lung cancer (SCLC) cells in vitro. Subline 2 was sensitive to a number of drugs, namely, vincristine (VCR), cyclophosphamide (CPM), adriamycin (ADR), and cisplatin (CDDP), whereas subline 1 was resistant to many drugs. The patient was treated with a combination of 44 Gy of whole-brain irradiation and a number of cycles of chemotherapy comprised of ADR, VCR, and CPM, followed by CDDP, VCR, and CPM, based on the results of sensitivity testing of the subline 2 cells. As a result, the patient has been disease-free for more than 5 years postoperatively. In conclusion, this case report serves to demonstrate that meticulous combined-modality treatment taking tumor heterogeneity in human cancers into account may be necessary to achieve breakthroughs in current cancer therapy for advanced lung cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

High-glucose-induced nuclear factor kappaB activation in vascular smooth muscle cells.

OBJECTIVE: Vascular smooth muscle cell (VSMC) dysfunction plays a role in diabetic macrovasculopathy. This dysfunction may be caused or exacerbated by expression of many of genes potently activated by the transcriptional factor nuclear factor kappaB (NF-kappaB). We have examined whether culture of VSMCs under high glucose conditions to stimulate the diabetic state can lead to the activation of NF-kappaB. METHODS: NF-kappaB activation was assessed in VSMCs stably transfected with a cis-reporter plasmid containing the NF-kappaB binding sites. RESULTS: Within 3-h incubation, high glucose (27.5 or 55 mmol/l) alone induced an increase in NF-kappaB activity in VSMCs; this increase was mimicked by mannitol given to deliver the same osmolar stress to the cells. High glucose or mannitol also enhanced TNFalpha-stimulated NF-kappaB activity. Incubation with high glucose for 48 h followed by stimulation with TNFalpha led to a marked potentiation of NF-kappaB activation compared with normoglycemic (5.5 mmol/l) VSMCs exposed to TNFalpha, while mannitol attenuated this effect. A 48-h incubation with high glucose substantially reduced glutathione (GSH) levels compared with normoglycemic VSMCs, whereas mannitol significantly increased GSH levels. An antioxidant N-acetyl-L-cysteine and a selective protein kinase C (PKC) inhibitor GF109203X significantly suppressed the TNFalpha-induced NF-kappaB activation, and abrogated potentiation of TNFalpha-induced NF-kappaB activity caused by high glucose (27.5 mmol/l). CONCLUSION: These results suggest that acutely high glucose causes alterations in osmolarity leading to activation of NF-kappaB, but that exposure to high glucose for more prolonged times causes changes in antioxidant defences and activation of PKC, which potentiates cytokine activation of NF-kappaB. Further definition of these pathways will help to delineate important signals mediating the aberrant behavior of VSMCs under hyperglycemic/diabetic conditions.

Acetylcysteine↗