Calculation of the Probability Distribution of CIBS Score in Different Relationships and Its Application / 法医学杂志

Objective To derive the probability distribution formula of combined identity by state （CIBS） score among individuals with different relationships based on population data of autosomal multiallelic genetic markers. Methods The probabilities of different identity by state （IBS） scores occurring at a single locus between two individuals with different relationships were derived based on the principle of ITO method. Then the distribution probability formula of CIBS score between two individuals with different relationships when a certain number of genetic markers were used for relationship identification was derived based on the multinomial distribution theory. The formula was compared with the CIBS probability distribution formula based on binomial distribution theory. Results Between individuals with a certain relationship, labelled as RS, the probabilities of IBS=2, 1 and 0 occurring at a certain autosomal genetic marker x （that is, p2（RSx）, p1（RSx） and p0（RSx））, can be calculated based on the allele frequency data of that genetic marker and the probability of two individuals with the corresponding RS relationship sharing 0, 1 or 2 identity by descent （IBD） alleles （that is, φ0, φ1 and φ2）. For a genotyping system with multiple independent genetic markers, the distribution of CIBS score between pairs of individuals with relationships other than parent-child can be deducted using the averages of the 3 probabilities of all genetic markers （that is, p2（RS）, p1（RS） and p0（RS））, based on multinomial distribution theory. Conclusion The calculation of CIBS score distribution formula can be extended to all kinships and has great application value in case interpretation and system effectiveness evaluation. In most situations, the results based on binomial distribution formula are similar to those based on the formula derived in this study, thus, there is little difference between the two methods in actual work.

Establishment of sleeve gastrectomy model in diet-induced obese Sprague-Dawley rats / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To establish sleeve gastrectomy(SG) rats model of obese type 2 diabetes mellitus(T2DM) for the research of hypoglycemic mechanism.</p><p><b>METHODS</b>Nine male Sprague-Dawley (6-week-old) rats were fed with high-sucrose and high-fat diet for 4 weeks, developing diet-induced obesity (DIO) rats model. The rats were then randomly divided into two groups. Six rats of them underwent sleeve gastrectomy(SG) as the sleeve gastrectomy group[SGG, body weight (471.8±17.9) g] and the other three rats underwent a laparotomy and stomach manipulation as the sham operative group[SOG, body weight (467.0±8.4) g]. The body weight, caloric intake and peripheral blood concentration of total ghrelin of rats were recorded after operation.</p><p><b>RESULTS</b>The weight of all the rats declined progressively after operation. The weight of the rats in SOG began to rise on the 5th postoperative day(POD) and regain their preoperative levels on the average 22nd POD. However, the weight of the rats in SGG began to rise slowly from the 9th POD, but was still lower than that of SOG[(487.4±10.1) g] and preoperative levels[(471.8±17.9) g] on the 28th POD[(420.1±18.6) g](P=0.001). Average caloric intake of rats in SGG was significantly lower than that of SOG after operation, but there was no significant difference between the two groups(P=0.121). The ghrelin level of SGG showed a continuous decreasing trend after intervention, decreased by 17.4% compared with the preoperative level (1595.1±14.4 ng/L) on the 28th POD[(1316.8±14.8) ng/L]. The ghrelin level of SOG did not change obviously before and after operation and both groups differ statistically(P=0.000).</p><p><b>CONCLUSIONS</b>A SG rat model is successfully established. This model can be used for the further study of mechanism analysis of T2DM resolution after surgery.</p>