High glucose inhibits the survival of HRMCs and its mechanism

OBJECTIVE

High glucose can promote the apoptosis of glomerular mesangial cells and cause diabetic nephropathy (DN). However, the mechanism remains unclear. In the present study, we investigated the effects of high glucose on the survival of human renal mesangial cells (HRMCs).

MATERIALS AND METHODS

Cells were treated with high glucose (30 mM) or normal glucose (5 mM) for 48 hours. Cell proliferation was determined by trypan blue assay. The relative expression of metalloproteinase-3 (TIMP3) and inflammatory factors detected by real-time polymerase chain reaction (PCR). Protein expression of Smad2/3, p-Smad2/3 and Smad7 in HRMCs were analyzed by Western blot.

RESULTS

Compared with normal glucose, we found that high glucose significantly inhibited cell survival, accompanied by the decrease of tissue metalloproteinase-3 (TIMP3) mRNA expression. Western blot results showed that the expression of p-Smad2/3 was significantly up-regulated, the expression of Smad7 was significantly downregulated, and inflammatory factors IL-6/IL-8 mRNA expression were increased in the HRMCs cultured with the high glucose. We also found that, compared with the normal glucose, the level of MDA was significantly increased (p<0.01), and the level of SOD was significantly lower (p<0.05) in the HRMCs cultured with the high glucose.

CONCLUSIONS

These findings suggested that high glucose inhibited the survival of HRMCs and may be associated with the downregulation of TIMP3 expression, Smad signaling pathway, inflammation and oxidative stress.

Prevalence of erosive esophagitis and Barrett's esophagus in the adult Chinese population

BACKGROUND AND STUDY AIM

The aim of this study was to determine the prevalence, characteristics, and risk factors of erosive esophagitis and Barrett's esophagus in an adult Chinese population without gastroesophageal reflux symptoms.

PATIENTS AND METHODS

Between March 2006 and February 2007, consecutive individuals aged between 18 and 75 years, who underwent routine upper endoscopy as part of their regular medical examination were recruited. Demographic and medical information were collected. Erosive esophagitis was defined endoscopically as visible breaks of the distal esophageal mucosa. Barrett's esophagus was diagnosed endoscopically and confirmed histologically. "Silent GERD" was defined when erosive esophagitis and/or Barrett's esophagus were present in an individual without reflux symptoms.

RESULTS

Among the 2580 individuals included, erosive esophagitis and Barrett's esophagus were found in 4.3 % (n = 110) and 1.0 % (n = 27), respectively. In individuals with erosive esophagitis and Barrett's esophagus, 33.6 % and 40.7 %, respectively, were asymptomatic. Thus, the prevalence of erosive esophagitis and Barrett's esophagus in individuals without GERS was 1.6 % and 0.5 %, respectively, giving an overall prevalence of silent GERD of 2.0 % (46 / 2270). Multivariate analysis identified that male sex (odds ratio [OR] = 2.87, 95 % confidence interval [CI] 1.24 - 6.66; P = 0.014), hiatus hernia (OR = 9.68, 95 %CI 5.00 - 17.95; P < 0.001), and alcohol consumption (OR = 3.17, 95 %CI 1.44 - 6.97; P = 0.004) were positively associated with erosive esophagitis, whereas Helicobacter Pylori infection (OR = 0.37, 95 %CI 0.14 - 0.98; P = 0.046) was negatively associated with erosive esophagitis. Alcohol consumption (OR = 5.32, 95 %CI 1.55 - 13.33; P = 0.008) was positively associated with Barrett's esophagus in asymptomatic individuals.

CONCLUSION

In this cohort of the adult Chinese population without reflux symptoms, the prevalence of erosive esophagitis and Barrett's esophagus is 1.6 % and 0.5 %, respectively, with an overall prevalence of silent GERD of 2.0 %. Male sex, hiatus hernia, and alcohol consumption are positively associated with erosive esophagitis, whereas a negative association exists for H. pylori infection. Alcohol consumption is positively associated with Barrett's esophagus.

A population-based epidemiologic study of irritable bowel syndrome in South China: stratified randomized study by cluster sampling

BACKGROUND

The detailed population-based data on irritable bowel syndrome in South China are lacking.

AIMS

To assess the prevalence of irritable bowel syndrome in South China and its impact on health-related quality of life.

SUBJECTS AND METHODS

A face-to-face interview was carried out in South China to assess the prevalence of irritable bowel syndrome. Random clustered sampling of permanent inhabitants aged 18-80 years was carried out under stratification of urban and suburban areas. The impact of irritable bowel syndrome on health-related quality of life was evaluated using the Chinese version of SF-36.

RESULTS

A total of 4178 subjects (1907 male and 2271 female) were interviewed. The adjusted prevalence of irritable bowel syndrome in South China is 11.50% according to the Manning criteria and 5.67% according to the Rome II criteria. Factors including history of analgesic use such as non-steroidal anti-inflammatory drug (odds ratio 3.83), history of food allergies (odds ratio 2.68), psychological distress (odds ratio 2.18), life events (odds ratio 1.89), history of dysentery (odds ratio 1.63) and negative coping style (odds ratio 1.28) were significantly associated with the presence of irritable bowel syndrome (P < 0.05). Irritable bowel syndrome was significantly associated with a decrement in health-related quality of life score.

CONCLUSION

Irritable bowel syndrome is a common disorder in South China and has a negative impact on health-related quality of life.

B subunit of cholera toxin produced in Escherichia coli

An engineered E. coli strain containing high expression level of CT-B subunits has been obtained by the application of recombinant DNA techniques. The B subunit can be secreted into the medium and reaches 20-40 micrograms/ml when this strain is incubated in a 50 l fermentation tank. The CT-B subunit purified with affinity chromatography in E. coli has the same characters as the natural CT-B subunit in molecular weight, N terminal amino acid analysis and antigenicity. The CT-B subunit has good immunogenicity and can be used as a preparation for protecting against diarrhea caused by V. cholera and enterotoxigenic E. coli. It can also be used as a vector for hepatins.

Construction of a bivalent oral vaccine for prevention of typhoid fever and cholera diarrhea

A recombinant plasmid pMM-CTB containing the gene for production of the nontoxic B subunit of Vibrio cholera was transferred into a safe, effective and attenuated oral vaccine Ty21a strain of Salmonella typhi. The resulting Ty21a (pMM-CTB) could steadily produce CT-B subunit that was secreted extracellularly and had the same antigenicity as CT-B produced by V. cholera. Furthermore, the characteristics of the antigenicity, the persistance in mice and the galactose sensitivity possessed in the strain of Ty21a were also retained in Ty21a (pMM-CTB). A bivalent vaccine containing Ty21a (pMM-CTB) and the killed whole cell of V. cholera was then constructed which had good immunogenecity for typhoid fever and cholera diarrhea.

The expression of enterotoxin A-B+ gene of V. cholerae in E. coli

The cloning in E. coli of a cholerae toxin gene that is A-B+ has been successfully constructed by using DNA recombinant techniques. E. coli cells carrying the recombinant plasmid pMM-CTB have been shown to produce a large amount of CTB subunits which are secreted as extracellular proteins.