ABSTRACT
Gut microbiome sequencing studies have great potential to translate microbial analysis outcomes into human health research. Sequencing strategies of 16S amplicon and whole-metagenome shotgun (WMS) are two main methods in microbiome research with respective advantages. However, how sample heterogeneity, sequencers and library preparation protocols affect the sequencing reproducibility of gut microbiome needs further investigation. This study aims to provide a reference for the selection of sequencing technologies by comparing differences in microbial composition from different sampling sites. The results of three widely adopted sequencers showed that the technical repetition correlation (r= 0. 94) was high in WMS method, while the biological repetition correlation (r = 0. 69) was low. Bray-Curtis distance identified that dissimilarity from biological replicates was larger than that of technical replicates (P<0. 001). In addition, dissimilarity and specific taxonomic profiles were observed between 16S and WMS datasets. Our results imply that homogenization is a necessary step before sample DNA extraction. The sequencers contributed less to taxonomic variation than the library preparation protocols. We developed an empirical Bayes approach that " borrowed information" in calculations and analyzed batch effect parameters using standardized data and prior distributions of (non-) parameters, which may improve population comparability between 16S and WMS and provide a basis for further application to fusion analysis of published 16S and microbial datasets.
ABSTRACT
<p><b>OBJECTIVE</b>To study clinical outcomes of serial tightening of reserved suture threads in delayed incision closure.</p><p><b>METHODS</b>From January 2005 to June 2013, 67 patients with delayed incision closure were treated with serial tightening of reserved suture threads. There were 37 males and 30 females, with an average age of 40 years old (ranged from 12 to 75 years old). Among them, 36 patients suffering from leg or forearm double fractures had the incision difficult to those primarily due to high tension or mergency; 13 patients had open wound which lasted for more than routine time for debridement and closure; 9 patients had wound infection; 9 patients had decompression incisions owing to compartment syndrome. The No. 4 suture thread was used to sew up the incision, and the 4 to 6 cm long thread was reserved at two ends of each thread. The reserved thread was tightened gradually from 2 to 4 days after operation according to conditions of swelling relieving. Finally, the reserved thread was not tied until the incision was completely closed.</p><p><b>RESULTS</b>After operation, the reserved threads were tightened and tied for 1 time in 6 patients, 2 times in 23 patients, 3 times in 27 patients, 4 times in 11 patients. Postoperative closure time ranged from 3 to 9 days, with an average of 6.2 days. All the incisions got delayed primary healing.</p><p><b>CONCLUSION</b>The method of serial tightening of reserved suture threads to close delayed incision closure avoids a second operation, which is simple and obtains a fine result.</p>