Anti-inflammatory mechanism of oxymatrine in dextran sulfate sodium-induced colitis of rats

AIM： To investigate the anti-inflammatory mechanism of oxymatrine in dextran sulfate sodium （DSS）-induced colitis of rats. METHODS： Acute colitis was induced by giving 2% DSS orally in drinking water for 8 d. Twenty-six male rats were randomized into oxymatrine-treated group （group A, 10 rats）, DSS control （group B, 10 rats） and normal control （group C, 6 rats）. The rats in group A were injected muscularly with oxymatrine at the dosage of 63 mg/（kg·d） from d 1 to 11 and drank 2% DSS solution from d 4 to 11. The rats in group B were treated with 0.9% saline in an equal volume as group A and drank 2% DSS solution from d 4 to 11. The rats in group C were treated with 0.9% saline as group B from d 1 to 11 and drank water normally. Diarrhea and bloody stool as well as colonic histology were observed. The levels of serum tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） were determined by ELISA, and nuclear factor-κB （NF-κB） activity and the expression of inter-cellular adhesion molecule-1 （ICAM-1） in colonic mucosa were detected by immunohistochemistry method. RESULTS： Compared with DSS control group, the inflammatory symptoms and histological damages of colonic mucosa in oxymatrine-treated group were significantly improved, the serum levels of TNF-α, IL-6, and the expression of NF-κB, ICAM-1 in colonic mucosa were significantly reduced. CONCLUSION： The fact that oxymatrine can reduce the serum levels of TNF-α, IL-6, and the expression of NF-κB and ICAM-1 in colonic mucosa in DSS-induced colitis of rats indicates that oxymatrine may ameliorate the colonic inflammation and thus alleviate diarrhea and bloody stool.

Predictive value of neutrophil infiltration as a marker of Helicobacter pylori infection

AIM： To evaluate the predictive value of neutrophil in- filtration as a marker of Helicobacter pylori （H. pyloni） infection. METHODS： A total of 315 patients with dyspepsia symptoms who underwent upper gastrointestinal en- doscopy were enrolled in this study. Biopsies were evaluated using the updated Sydney system. The medication history of all patients in the preceding 4 wk was recorded. The diagnosis of H. pylori infection was based on 13C-urea breath test at least 4 wk after with- drawal of antisecretory drugs, antibiotics and related drugs. For the patients with subtotal gastrectomy, the diagnosis of H. pylori infection was based on anti-H. pylori immunoglobulin G （IgG） antibody. Serum anti-H. pylori IgG antibody was measured by enzyme-linked immunosorbent assays （Biohit, Finland）. RESULTS： The sensitivity, specificity, positive predic- tive value and negative predictive value of neutrophil infiltration in the diagnosis ofH, pylorlinfection were 92.3%, 83.5%, 77.4% and 94.7%, respectively. Neu- trophil infiltration of gastric mucosa in the histological analysis was strongly associated withH, pylorlinfection （77.4% vs 5.3% in the neutrophil infiltration negative group, P = 0.000）. Moderate neutrophil infiltration was more frequent in H. pylorl infection when compared to mild infiltration （81.8% and 75%, respectively）, but did not reach statistical significance. For those patients with negative rapid urease test, H. pylori was detected in 73.2% of patients with positive neutrophil infiltration on histology. In patients with subtotal gastrectomy, the diagnostic accuracy of neutrophil infiltration in H. pylori infection was 50%. CONCLUSION： Neutrophil infiltration is closely associ- ated withH, pylori and may be recognized as a sign of this infection.

Sequential loss of genetic variation in flea beetle Agasicles hygrophila （Coleoptera： Chrysomelidae） following introduction into China

The flea beetle （Agasicles hygrophila） was imported to Florida, USA and then introduced from Florida into China in 1987 as a biological control agent for the invasive plant alligator weed （Alternanthera philoxeroides）. The initial beetle population was subsequently used for sequential introductions in other areas of China, but little is known about the genetic consequences of the introductions. In this study, the genetic diversity and population structure of five beetle populations, the source Florida population, three intentionally introduced China populations and one accidentally dispersed China population, were examined using amplified fragment length polymorphisms. The results showed a clear pattern of decreasing genetic diversity with the sequential introductions. The diversity was highest in the Florida population followed by the first introduction to Chongqing and then in Kunming and Fuzhou. The lowest diversity was found in the accidentally dispersed Guangzhou population that was first recorded in 1996. Both loci parameters and Nei＇s genetic diversity showed a high variation among these populations. Genetic differentiation among populations was further verified by the GST statistic （0.136–0.432）. Beetles in Kunming had the highest gene flow with those in Guangzhou, and therefore lowest differentiation and closest genetic distance. These data show that sequential introduction influenced the genetic diversity of populations in China. Genetic diversity should be considered in planning introduction and long-term maintenance of populations.

Spikes with short inter-spike intervals in frog retinal ganglion cells are more correlated with their adjacent neurons’activities

Correlated firings among neurons have been extensively investigated;however,previous studies on retinal ganglion cell(RGC)population activities were mainly based on analyzing the correlated activities between the entire spike trains.In the present study,the correlation properties were explored based on burst-like activities and solitary spikes separately.The results indicate that:(1)burst-like activities were more correlated with other neurons’activities;(2)burst-like spikes correlated with their neighboring neurons represented a smaller receptive field than that of correlated solitary spikes.These results suggest that correlated burst-like spikes should be more efficient in signal transmission,and could encode more detailed spatial information.