An Innovative Model of ISS-Based Multiple Fractures and Gastrointestinal Dysfunction Related to c-Kit Protein Expression on Interstitial Cells of Cajal.

OBJECTIVE: Gastrointestinal dysfunction seriously affects the prognosis and quality of life of patients with multiple fractures. However, experimental evidence of this relationship is lacking. Here we describe a newly developed mouse model of postoperative gastrointestinal dysfunction after multiple fractures. METHODS: Trauma severity was assessed using the injury severity score (ISS). Based on the ISS, a multiple fracture model was established in mice as follows: limb fractures with pelvic fractures and multiple rib fractures; limb fractures with multiple rib fractures; closed fracture of both forelegs with pelvic fracture and rib fractures; closed limb fractures; limb fracture with pelvic fracture; spinal fractures; hind leg fractures with pelvic fractures; pelvic fracture with multiple rib fractures; closed fracture of both fore legs with pelvic fracture; and closed fracture of both fore legs with multiple rib fractures. In each model group, gastrointestinal motility was assayed and the histopathology of the small intestine was examined. Western blot and immunohistochemical analyses of jejunal tissue were performed to detect c-kit protein expression, the level of which was compared with that of a control group. The results of ANOVA are expressed as mean ± standard deviation. RESULTS: In mice with multiple fractures, food intake was greatly reduced, consistent with histopathological evidence of an injured intestinal epithelium. The jejunal tissue of mice in groups a, c, f, and h was characterized by extensively necrotic and exfoliated intestinal mucosal epithelium and inflammatory cell infiltration in the lamina propria. In the gastrointestinal function assay, gastrointestinal motility was significantly reduced in groups a, b, c, f, and g; these group also had a higher ISS (p < 0.01). The expression of c-kit protein in groups with gastrointestinal dysfunction was significantly up-regulated (p < 0.001) compared with the control group. The close correlation between c-kit expression and the ISS indicated an influence of trauma severity on gastrointestinal motility. CONCLUSION: Gastrointestinal dysfunction after multiple fractures was successfully reproduced in a mouse model. In these mice, c-kit expression correlated with gastrointestinal tissue dysfunction and might serve as a therapeutic target.

[Detection of rpoB gene mutations in Mycobacterium tuberculosis].

ABSTRACT With Mycobacterium tuberculosis H37Rv as a control, the mutations of rpoB gene from 37 Mycobacterium tuberculosis clinical isolates (18 rifampin-resistant strains and 19 rifampin-susceptible strains) have been detected by polymerase chain reaction-single strand conformation polymorphism(PCR-SSCP) under standard condition (no glycerol in gel). For the strains in which mutations had not been detected under standard condition, PCR-SSCP analysis was performed again on condition that 8% glycerol was added to gel. In addition, the PCR products of rpoB genes of 30 strains (18 rifampin-resistant strains and 12 rifampin-susceptible strains) were detected by DNA sequencing. After twice analyses of PCR-SSCP, in 18 rifampin-resistant strains, the patterns of 17 strains were found to be abnormal; and in 19 rifampin-susceptible strains, the patterns of 16 strains were found to be normal. Compared with routine drug susceptibility test, the sensitivity of PCR-SSCP 94.4% is higher for rifampin resistance detection, and specificity of PCR -SSCP 84% seems lower. The results of sequence analysis were shown as: amomg 18 rifampin-resistant strains, only one has deletion in codons 513 and 514 of rpoB gene, which is a new report, the others have point mutation; among 12 rifampin- susceptible strains, 3 positive strains in SSCP occur gene mutations directly related to rifampin resistance. Then compared with DNA sequencing, the accuracy, sensitivity and specificity of PCR-SSCP are 96.7%, 95.2% and 100% respectively. Therefore, the sensitivity of mutation detection in SSCP could be improved by adding glycerol in gel. It is feasible and efficient to detect the mutation of rpoB gene in Mycobacterium tuberculosis by PCR-SSCP. This method is valuable to evaluate the rifampin resistance of Mycobacterium tuberculosis in clinical application for curing tuberculosis.

Genetic diversity and population history of golden monkeys (Rhinopithecus roxellana).

Golden monkey (Rhinopithecus roxellana), namely the snub-nosed monkey, is a well-known endangered primate, which distributes only in the central part of mainland China. As an effort to understand the current genetic status as well as population history of this species, we collected a sample of 32 individuals from four different regions, which cover the major habitat of this species. Forty-four allozyme loci were surveyed in our study by allozyme electrophoresis, none of which was found to be polymorphic. The void of polymorphism compared with that of other nonhuman primates is surprising particularly considering that the current population size is many times larger than that of some other endangered species. Since many independent loci are surveyed in this study, the most plausible explanation for our observation is that the population has experienced a recent bottleneck. We used a coalescent approach to explore various scenarios of population bottleneck and concluded that the most recent bottleneck could have happened within the last 15,000 years. Moreover, the proposed simulation approach could be useful to researchers who need to analyze the non- or low-polymorphism data.