ASGE guideline: colorectal cancer screening and surveillance.
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Biomedical subjects
Publications and source records attributed to Bo Shen.
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Kallistatin is a serine proteinase inhibitor that has been shown to reduce joint swelling and to inhibit inflammation in a rat model of arthritis. In this study, we investigated the effect and mechanisms of kallistatin on cardiac function after myocardial ischemia-reperfusion (I/R) injury. The human kallistatin gene in an adenoviral vector was delivered locally into rat heart 4 days before 30-min ischemia followed by 24-hr reperfusion. Kallistatin gene transfer significantly reduced myocardial infarct size and left ventricle end-diastolic pressure and improved cardiac contractility. Kallistatin significantly reduced I/R-induced cardiomyocyte apoptosis as identified by TUNEL and Hoechst staining, DNA laddering, cell viability, and caspase-3 activity in ischemic myocardium and in primary cultured cardiomyocytes. Kallistatin also reduced intramyocardial monocyte/macrophage and neutrophil accumulation in conjunction with decreased expression of monocyte chemoattractant protein-1, tumor necrosis factor-alpha, and intercellular adhesion molecule-1. Kallistatin delivery promoted cardiac endothelial nitric oxide synthase activation and increased nitric oxide (NO) formation, but inhibited NADH oxidase activity, p22phox expression, and superoxide production. Moreover, kallistatin reduced the phosphorylation of apoptosis signal-regulating kinase-1 and mitogen-activated protein kinases (MAPKs), but increased Akt and glycogen synthase kinase-3beta phosphorylation. The effects of kallistatin on cardiac function, oxidative stress, and these signal transduction events were all blocked by Nomega-nitro-L-argi-nine methyl ester. These results indicate a novel role of kallistatin in cardiac protection after I/R injury through increased NO formation and Akt-glycogen synthase kinase-3beta signaling and suppression of oxidative stress and MAPK activation.
Evidence suggests that the progression of renal fibrosis is a reversible process. Because inflammation plays a crucial role in the development of renal injury, we examined the effect of kallikrein and activation of the kinin B2 receptor on the reversal of salt-induced inflammation and renal fibrosis in Dahl salt-sensitive (DSS) rats. Four weeks after high salt loading, when renal injury was apparent, adenovirus harboring the human tissue kallikrein gene was injected into DSS rats. To determine the role of the B2 receptor in mediating the actions of kallikrein, icatibant, a kinin B2 receptor antagonist, was infused with kallikrein gene delivery. Two weeks after adenovirus injection, salt-induced glomerular sclerosis, tubular protein cast formation, and monocyte/ macrophage accumulation in the kidney were notably reversed by kallikrein. Decreased intercellular adhesion molecule-1 expression paralleled this observation. Kallikrein gene delivery also dramatically reduced collagens I, III, and IV and reticulin deposition, accompanied by a decline in myofibroblast accumulation and transforming growth factor-beta(1) expression. Moreover, kallikrein reversed salt-induced glomerular hypertrophy and inhibited the increase in levels of the cell cycle-inhibitory proteins p21 and p27. These protective actions of kallikrein were abolished by icatibant, indicating a B2 receptor-mediated event. In addition, kallikrein protected against salt-induced renal injury by diminishing urinary protein and blood urea nitrogen levels. Furthermore, kallikrein gene delivery restored nitric oxide production and suppressed NADH oxidase activity and superoxide generation. These results indicate that tissue kallikrein, through the kinin B2 receptor, reverses salt-induced inflammation, renal fibrosis, and glomerular hypertrophy via suppression of oxidative stress.
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BACKGROUND: Crohn's disease (CD) of the pouch can occur in patients with colectomy and ileal pouch-anal anastomosis (IPAA) originally performed for a preoperative diagnosis of ulcerative colitis. The clinical presentations of CD of the pouch are inflammatory, fibrostenotic, and fistulizing. Risk factors for clinical phenotypes of CD of the pouch have not been characterized. METHODS: A total of 78 eligible patients with CD of the pouch together with 294 nonselected non-CD patients with IPAA seen in the Pouchitis Clinic were enrolled, including 28 with inflammatory CD, 18 with fibrostenotic CD, and 32 with fistulizing CD. The clinical phenotypes of CD were diagnosed based on a combined assessment of clinical, endoscopic, radiographic, and histologic features. Three separate analyses were performed, and for each analysis, the outcome of interest was having one of the phenotypes versus not having it. A stepwise selection multivariable logistic regression analysis was used. RESULTS: In the multivariable analysis, the risk factor for inflammatory CD was higher afferent-limb endoscopy scores (hazard ratio [HR] 1.87 95% confidence interval [CI] 1.54-2.27); the risk factors for fibrostenotic CD were higher afferent-limb (95% CI 1.81-3.48, HR 2.51) and higher cuff (95% CI 1.01-1.84, HR 1.36) endoscopy scores; and for fistulizing CD the risk factors were younger age (95% CI 0.93-0.99, HR 0.96), female gender (95% CI 1.35-6.97, HR 3.07), a preoperative diagnosis of indeterminate colitis (95% CI 1.72-9.34, HR 4.00), and no use of nonsteroidal antiinflammatory drugs (95% CI 1.31-8.25, HR 3.28). CONCLUSIONS: Each of the three phenotypes of CD of the pouch was associated with certain risk factors, suggesting that each of these diseases has a different etiology and disease process. The identification and management of some of the modifiable risk factors may reduce CD-related morbidity.
OBJECTIVE: To detect the expression of RhoC protein in human primary hepatocellular carcinoma (HCC) and pericancerous liver (PCL) tissues and its relation to HCC prognosis. METHODS: Immunohistochemical method was used to detect the expression of RhoC protein in HCC, PCL of 43 patients. Thirty-six patients were followed up after they received radical resection. RESULT: The expression of RhoC protein in HCC was significantly higher than that in PCL. Rhoc expression was increased in cases with poor differentiation, portal vascular invasion, unintact envelope and multiple masses. The survival analysis showed that HCC with lower RhoC protein expression had better clinical outcomes. CONCLUSION: RhoC protein expression is correlated with infiltration and metastasis in HCC. RhoC protein can be used as a prognostic indicator for HCC.
This paper studied the grain quality and Q-enzyme activity of three rice varieties and their combinations as affected by air temperature and sink-source volume. The results showed that at the early stage of milk filling, the grains of fully milk filling under high temperature had a higher chalkiness, lower transparency, and lower rate of white rice. Compared with the grain of early-rice, that of late rice had higher gel consistency and transparency, and higher rate of white rice. Planting rice at early-or late season had no significant effect on the amylose and protein contents of rice grain. Leaf-cutting to limit source decreased grain quality markedly, while grain-thinning to decrease sink improved grain quality significantly.
The pathogenesis of Crohn's disease (CD), an idiopathic inflammatory bowel disease, is attributed, in part, to intestinal bacteria that may initiate and perpetuate mucosal inflammation in genetically susceptible individuals. Paneth cells (PC) are the major source of antimicrobial peptides in the small intestine, including human alpha-defensins HD5 and HD6. We tested the hypothesis that reduced expression of PC alpha-defensins compromises mucosal host defenses and predisposes patients to CD of the ileum. We report that patients with CD of the ileum have reduced antibacterial activity in their intestinal mucosal extracts. These specimens also showed decreased expression of PC alpha-defensins, whereas the expression of eight other PC products either remained unchanged or increased when compared with controls. The specific decrease of alpha-defensins was independent of the degree of inflammation in the specimens and was not observed in either CD of the colon, ulcerative colitis, or pouchitis. The functional consequence of alpha-defensin expression levels was examined by using a transgenic mouse model, where we found changes in HD5 expression levels, comparable to those observed in CD, had a pronounced impact on the luminal microbiota. Thus, the specific deficiency of PC defensins that characterizes ileal CD may compromise innate immune defenses of the ileal mucosa and initiate and/or perpetuate this disease.
Cysteine is the first organic product of sulfate assimilation and as such is the precursor of all molecules containing reduced sulfur including methionine, glutathione, and their many metabolites. In plants, 5'-adenylylsulfate (APS) reductase is hypothesized to be a key regulatory point in sulfate assimilation and reduction. APS reductase catalyzes the two-electron reduction of APS to sulfite using glutathione as an electron donor. This paper reviews the experimental basis for this hypothesis. In addition, the results of an experiment designed to test the hypothesis by bypassing the endogenous APS reductase and its regulatory mechanisms are described. Two different bacterial assimilatory reductases were expressed in transgenic Zea mays, the thioredoxin-dependent APS reductase from Pseudomonas aeruginosa and the thioredoxin-dependent 3'-phosphoadenylylsulfate reductase from Escherichia coli. Each of them was placed under transcriptional control of the ubiquitin promoter and the protein products were targeted to chloroplasts. The leaves of transgenic Z. mays lines showed significant accumulation of reduced organic thiol compounds including cysteine, gamma-glutamylcysteine, and glutathione; and reduced inorganic forms of sulfur including sulfite and thiosulfate. Both bacterial enzymes appeared to be equally capable of deregulating the assimilative sulfate reduction pathway. The reduced sulfur compounds accumulated to such high levels that the transgenic plants showed evidence of toxicity. The results provide additional evidence that APS reductase is a major control point for sulfate reduction in Z. mays.
AIM: To investigate the cyclooxygenase-2 (COX-2) expression level in human HepG2, Bel-7402 and SMMC-7721 hepatoma cell lines and the molecular mechanism of COX-2 selective inhibitor celecoxib-induced cell growth inhibition and cell apoptosis. METHODS: Hepatoma cells were cultured and treated with celecoxib. Cell in situ hybridization (ISH) and immunocytochemistry were used to detect COX-2 mRNA and protein expression. Proliferating cell nuclear antigen and phosphorylated Akt were also detected by immunocytochemistry assay. Cell growth rates were assessed by 3-(4, 5-dimethylthiazol-2-yl-2, 5-diphenyltetrazolium (MTT) bromide colorimetric assay. Celecoxib-induced cell apoptosis was measured by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and flow cytometry (FCM). The phosphorylated Akt and activated fragments of caspase-9, caspase-3 were examined by Western blotting analysis. RESULTS: Increased COX-2 mRNA and protein expression were detected in all three hepatoma cell lines. Celecoxib could significantly inhibit cell growth and the inhibitory effect was in a dose- and time-dependent manner evidenced by MTT assays and morphological changes. The apoptotic index measured by TUNEL increased correspondingly with the increased concentration of celecoxib and the reaction time. With 50 micromol/L celecoxib treatment for 24 h, the apoptotic index of HepG2, BEL-7402 and SMMC-7721 cells was 25.01+/-3.08%, 26.40+/-3.05%, and 30.60+/-2.89%, respectively. Western blotting analysis showed remarkable activation of caspase-9, caspase-3 and dephosphorylation of Akt (Thr(308)). Immunocytochemistry also showed the reduction of PCNA expression and phosphorylation Akt (Thr(308)) after treatment with celecoxib. CONCLUSION: COX-2 mRNA and protein overexpression in HepG2, Bel-7402 and SMMC-7721 cell lines correlate with the increased cell growth rate. Celecoxib can inhibit proliferation and induce apoptosis of hepatoma cell strains in a dose- and time-dependent manner.
Supercritical carbon dioxide, with and without a methanol modifier, was used to extract sinomenine from Sinomenium acutum (Thumb) Rehd et Wils. Sinomenine determinations were carried out using high-performance liquid chromatography (HPLC). The results show that the yield obtained after 2.5 h extraction with methanol-modified supercritical carbon dioxide was the highest (7.47 mg/g), while that obtained with only supercritical carbon dioxide was the lowest (0.17 mg/g). The recovery obtained with supercritical carbon dioxide, with and without a methanol modifier, could not be increased greatly by the method of the alkalinization of sample. Higher recoveries were obtained than extraction using methanol in Soxhlet extractor.
Two serine proteinase genes were isolated from Culex pipiens pallens as significantly up-regulated genes in a deltamethrin-resistant strain through a combination of suppression substractive hybridization and gene expression profiling by macroarrays. These two genes were found to be expressed at least threefold higher in the resistant strain than in the susceptible one. By using rapid amplification of cDNA ends to screen the constructed cDNA library, we cloned these two sequences. There were 909 bp with an open reading frame of 786 bp in the sequence of trypsin cDNA (GenBank/NCBI AF468495), the deduced protein had 261 amino acids, which was most similar to the trypsin gene of Anopheles gambiae. There were 992 bp with an open reading frame of 816 bp in the chymotrypsin cDNA (GenBank/NCBI AY034060), and its deduced amino acid sequence had 271 amino acids, which was most similar to the chymotrypsin-like protein from Aedes aegypti. The two genes were stably expressed in mosquito C6/36 cells, and the expected 29 and 30 kDa bands were shown with Western blot, respectively. In these cells, after deltamethrin treatment, they had protective effects on the viability. The results indicate that trypsin and chymotrypsin were more highly expressed in the deltamethrin-resistant strain, and was related to insecticide resistance in mosquitoes, Cx. pipiens pallens.
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