Pathway analysis of differentially expressed genes in human esophageal squamous cell carcinoma.

OBJECTIVE: Esophageal Squamous Cell Carcinoma (ESCC) is one of the most common human cancers with a particularly high incidence in certain regions of China. Differentially expressed genes (DEG) between the esophageal squamous carcinoma tissues and matched normal esophageal mucosal epithelial tissues can be detected by employing the gene microarray technology. This can aid the analysis of the underlying disease mechanism and can help to identify potentially critical genes as well as related molecular signalling pathways. MATERIALS AND METHODS: The potentially critical genes and related signal pathways are examined by bioinformatics analysis including Gene Ontology (GO) analysis, pathway analysis and signal transduction networks. Here, we performed microarray analysis with 8 pairs of ESCC and normal esophageal mucosal epithelial tissues. RESULTS: Compared to the control group, 347 and 203 genes were found to be up-regulated and down-regulated in the experimental group, respectively. Based on pathway analysis, 52 and 51 signal transduction pathways were involved in the up-regulated and the down-regulated genes, respectively. SLC27A6, RAB11A, ABCA8, JAM2, HNMT, GSTM1, and CDKN3, which play critical roles in regulating the expression of ESCC, were identified among the key genes involved in the signal transduction networks. CONCLUSIONS: Investigation of the mechanism underlying ESCC can provide a direction for the clinical prevention and treatment of ESCC.

Promoter hypermethylation of cyclooxygenase-2 gene in esophageal squamous cell carcinoma.

Cyclooxygenase-2 (COX-2) is overexpressed in various types of human malignancies including esophageal squamous cell carcinoma (ESCC). However, a subset of ESCC either do not express COX-2 or show low level of expression. It is well established that promoter methylation is a major mechanism that mediates transcriptional silencing of COX-2 in gastric and colorectal cancer, but the data on ESCC are very limited. In this study, we attempted to determine whether COX-2 expression was also regulated by promoter methylation in human ESCC cell lines. We examined the methylation status of the COX-2 promoter in five human ESCC cell lines (EC109, EC9706, KYSE 410, KYSE 150, TE-1) using bisulfite sequencing analysis. Western blot analysis was used to determine COX-2 expression. Quantitative real-time polymerase chain reaction was used to determine COX-2 mRNA level. Prostaglandin (PG) E(2) was detected by ELISA. The promoter was densely methylated in TE-1 and KYSE 150, which had a low level of COX-2 expression and less methylated in other three cell lines (EC109, EC9706, KYSE 410), with high level of COX-2 expression. Treatment with 5-aza-deoxycytidine (5-aza-DC), a DNA methyltransferase inhibitor, demethylated the promoter and upregulated COX-2 expression, as well as PGE(2) production in TE-1 and KYSE 150. However, no such effects were observed in EC109. COX-2 protein was negative, but mRNA was positive in TE-1. After treatment with 5-aza-DC, both COX-2 mRNA and protein level had increased. These findings suggest that the promoter methylation may be one of the mechanisms that regulate COX-2 expression in ESCC.

Atrial natriuretic peptide blunts arterial baroreflex in spontaneously hypertensive rats.

We and other laboratories have reported that arterial baroreflex-mediated control of heart rate is blunted in spontaneously hypertensive rats (SHR) compared with normotensive controls. Recently, we reported that atrial natriuretic peptide (ANP) microinjected into the caudal nucleus tractus solitarii of SHR further blunts this defect. The present study tested the hypothesis that ANP modulates arterial baroreflex-mediated control of sympathetic nervous system activity. Nine-week-old, male SHR (n = 29) and normotensive Wistar-Kyoto control rats (n = 24) were instrumented for microinjection into the caudal nucleus tractus solitarii and for direct measurement of arterial blood pressure, heart rate, and lumbar sympathetic nervous system activity. After urethane- and alpha-chloralose-induced induced anesthesia, arterial baroreflex-mediated control of heart rate and lumbar sympathetic nerve activity was assessed during phenylephrine- (5 to 40 micrograms.kg-1.min-1) induced increases and sodium nitroprusside- (15 to 300 micrograms.kg-1.min-1) induced decreases in mean blood pressure before and after microinjection of ANP (50 ng) or monoclonal antibody to ANP (0.55 micrograms) into the caudal nucleus tractus solitarii. ANP reduced and the antibody enhanced the sensitivity of baroreflex-mediated control of both heart rate and lumbar sympathetic nerve activity in SHR but not in Wistar-Kyoto controls (P < .05). Arterial baroreflex sensitivity was unchanged with control microinjections of vehicle or mouse IgG in SHR. These data suggest that endogenous ANP in the caudal nucleus tractus solitarii may contribute to the development and/or maintenance of hypertension in SHR by blunting baroreflex-mediated control of sympathetic nervous system activity.

Gender and dietary NaCl in spontaneously hypertensive and Wistar-Kyoto rats.

We recently reported that high dietary NaCl exposure significantly increases both daytime and nighttime mean arterial pressure in male spontaneously hypertensive rats (SHR) but only nighttime values in male normotensive Wistar-Kyoto rats (WKY). In the present study we used a telemetry monitoring system to evaluate the effects of high dietary NaCl exposure on diurnal variation of mean arterial pressure and heart rate in male and female SHR and WKY. After implantation of a radio-frequency transducer, rats were fed either high (8%) or basal (1%) NaCl diets for 2 weeks. High dietary NaCl ingestion significantly increased both daytime and nighttime mean arterial pressure in male SHR compared with males receiving a basal NaCl diet, resulting in greater 24-hour values (163 +/- versus 154 +/- 1 mm Hg, high versus basal NaCl diet; P < .05). High dietary NaCl ingestion significantly increased only nighttime blood pressure in male WKY, with no significant effect on 24-hour mean arterial pressure (102 +/- 2 versus 101 +/- 3 mm Hg, high versus basal). High dietary NaCl exposure did not affect daytime or nighttime mean arterial pressure in female SHR (24-hour mean arterial pressure, 144 +/- 2 versus 141 +/- 2 mm Hg, high versus basal NaCl diet). Twenty-four-hour mean arterial pressure tended to be lower in female WKY receiving a high NaCl diet than females ingesting a basal diet (101 +/- 3 versus 106 +/- 1 mm Hg), but the difference was not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

[The effect of teeth arrangement in maxillary complete denture on the stress distribution of bone tissue--photoelastic stress analysis].

In this paper, we make a study about the effects of 6 different kind of arrangement of the 1st molar in maxillary complete denture on the stress distribution of bone tissue. In intercuspation position, it is well-distributed when the artificial teeth are arranged on the top of alveolar ridge. There are stress concentration in the bone tissue. When the long axis of the teeth incline bucally or the teeth migrate away from the ridge center line. When the ridges relation is disharmonious, it is better that the teeth incline do not over 30 degrees buccally and the teeth migration do not over 5 mm horizontally.

[Risk of endogenous N-nitrosodimethylamine formed by dimethylamine in rats--precursors stability].

N-Nitrosodimethylamine (NDMA) is a potential carcinogen and present in our surroundings widely. NDMA can be formed by many precursors, Dimethylamine (DMA) is the most common precursor in food. To evaluate the risk of DMA nitrosation in vivo, so that men can do their best to reduce endogenous nitrosamine exposure, we carried out this research. This paper is the first part of our research. The stabilities of DMA and nitrite in the stomach were studied. DMA was stable and nitrite was decomposed at the speed of second-order reaction. The stabilities of nitrite in simulate gastric acid and in ascorbic (VC) solution also were studied. Nitrite decomposition in simulate gastric acid was very similar to the one in the stomach. VC solution at the equimolar with nitrite can decompose 53-79% of nitrite in one minute with shaking. We suggested that the efficiency of VC inhibiting endogenous nitrosation can be estimated on the basis of decomposing speed of nitrite and nitrosating speed by nitrite.