Insights into the biosynthesis of septacidin l-heptosamine moiety unveils a VOC family sugar epimerase

l-Heptopyranoses are important components of bacterial polysaccharides and biological active secondary metabolites like septacidin (SEP), which represents a group of nucleoside antibiotics with antitumor, antifungal, and pain-relief activities. However, little is known about the formation mechanisms of those l-heptose moieties. In this study, we deciphered the biosynthetic pathway of the l,l-gluco-heptosamine moiety in SEPs by functional characterizing four genes and proposed that SepI initiates the process by oxidizing the 4'-hydroxyl of l-glycero-α-d-manno-heptose moiety of SEP-328 ( 2) to a keto group. Subsequently, SepJ (C5 epimerase) and SepA (C3 epimerase) shape the 4'-keto-l-heptopyranose moiety by sequential epimerization reactions. At the last step, an aminotransferase SepG installs the 4'-amino group of the l,l-gluco-heptosamine moiety to generate SEP-327 ( 3). An interesting phenomenon is that the SEP intermediates with 4'-keto-l-heptopyranose moieties exist as special bicyclic sugars with hemiacetal-hemiketal structures. Notably, l-pyranose is usually converted from d-pyranose by bifunctional C3/C5 epimerase. SepA is an unprecedented monofunctional l-pyranose C3 epimerase. Further in silico and experimental studies revealed that it represents an overlooked metal dependent-sugar epimerase family bearing vicinal oxygen chelate (VOC) architecture.

Current treatment of juvenile nasopharyngeal carcinoma / 中华放射医学与防护杂志

Nasopharyngeal carcinoma (NPC) is a cancer arising from the nasopharynx epithelium, and is one of the most frequent head and neck malignancies in adolescents. Treatment strategies for juvenile NPC follow the guidelines established for adult NPC. However, juvenile NPC has its distinct clinical characteristics. For juvenile patients in the developmental stage, the late toxicity of treatment should not be ignored. Therefore, it is important to seek appropriate treatment strategies for juvenile NPC. This review gives an overview of the epidemiology, clinical characteristics and current treatment of juvenile NPC, along with the promising strategies to reduce the intensity of treatment in adolescents. This review aims to provide new insight for improving the treatment of this disease.

Comparison of intestinal microbial community succession based on different universal primer sets / 生物工程学报

The important role of intestinal microorganisms in human health has been widely confirmed. At present, most of the studies on intestinal microorganisms are based on amplification of the V3-V4 region of bacterial 16S rRNA gene, and little attention has been paid to archaea. In this study, a primer set which can amplify 16S rRNA gene of both bacteria and archaea at the same time was used. By comparing the community changes before and after probiotics intake, it showed that this primer set is suitable for analyzing the changes of human intestinal bacteria and archaea communities. The fecal samples of volunteers were collected, and the amplification and high-throughput sequencing were carried out by using bacterial primer set (B primer) and bacterial and archaeal universal primer (AB primer); several commonly used rRNA databases were used to determine the amplification ability of the primer set to bacteria and archaea. The results showed that AB primer could display the bacterial community amplified by B primer, and could obtain the sequence of common methanogenic archaea in intestinal tract. AB primer set can analyze the bacteria and archaea in the intestinal tract at the same time by only one amplification and sequencing, which can show the structure of intestinal microbial community more comprehensively, which is suitable for the research of intestinal microorganisms.

Protein engineering: from directed evolution to computational design / 生物工程学报

By constructing mutant libraries and utilizing high-throughput screening methods, directed evolution has emerged as the most popular strategy for protein design nowadays. In the past decade, taking advantages of computer performance and algorithms, computer-assisted protein design has rapidly developed and become a powerful method of protein engineering. Based on the simulation of protein structure and calculation of energy function, computational design can alter the substrate specificity and improve the thermostability of enzymes, as well as de novo design of artificial enzymes with expected functions. Recently, machine learning and other artificial intelligence technologies have also been applied to computational protein engineering, resulting in a series of remarkable applications. Along the lines of protein engineering, this paper reviews the progress and applications of computer-assisted protein design, and current trends and outlooks of the development.

Risk factors of complications after CT-guided percutaneous needle biopsy of lumps near pulmonary hilum / 华中科技大学学报（医学）（英德文版）

The factors influencing the incidence of common complications (pneumothorax and pulmonary hemorrhage) of CT-guided percutaneous needle biopsy of lumps near pulmonary hilum were investigated. CT-guided percutaneous needle biopsy of lumps near pulmonary hilum was performed on 48 patients. The complications of pneumothorax and pneumorrhagia as well as the contributing factors were analyzed statistically. The major complications associated with CT-guided needle biopsy included pneumothorax (13 cases, 27.1%) and pulmonary hemorrhage (14 cases, 20.24%). χ(2) test revealed that pneumothorax was associated with the lesion size and depth of needle penetration, and pulmonary hemorrhage with the depth of needle penetration and needle retention time with a significant P value. Pneumothorax was observed in 7 cases (17.5%) out of 40 cases with diameter of mass greater than 3 cm, and in 6 cases (60%) out of 10 cases with depth of needle penetration greater than 4 cm. Additionally, pulmonary hemorrhage was identified in 12 cases (41.4%) out of 29 cases with needle retention time longer than 15 min, and pulmonary hemorrhage in 7 cases (70%) out of 10 cases with depth of needle penetration greater than 4 cm. CT-guided percutaneous needle biopsy of lumps near pulmonary hilum is safe and effective. The key factors to prevent the complications include correct evaluation of lesion size, depth of needle penetration and the needle retention time before the operation.

Risk factors of complications after CT-guided percutaneous needle biopsy of lumps near pulmonary hilum / 华中科技大学学报（医学）（英德文版）

The factors influencing the incidence of common complications (pneumothorax and pulmonary hemorrhage) of CT-guided percutaneous needle biopsy of lumps near pulmonary hilum were investigated. CT-guided percutaneous needle biopsy of lumps near pulmonary hilum was performed on 48 patients. The complications of pneumothorax and pneumorrhagia as well as the contributing factors were analyzed statistically. The major complications associated with CT-guided needle biopsy included pneumothorax (13 cases, 27.1%) and pulmonary hemorrhage (14 cases, 20.24%). χ(2) test revealed that pneumothorax was associated with the lesion size and depth of needle penetration, and pulmonary hemorrhage with the depth of needle penetration and needle retention time with a significant P value. Pneumothorax was observed in 7 cases (17.5%) out of 40 cases with diameter of mass greater than 3 cm, and in 6 cases (60%) out of 10 cases with depth of needle penetration greater than 4 cm. Additionally, pulmonary hemorrhage was identified in 12 cases (41.4%) out of 29 cases with needle retention time longer than 15 min, and pulmonary hemorrhage in 7 cases (70%) out of 10 cases with depth of needle penetration greater than 4 cm. CT-guided percutaneous needle biopsy of lumps near pulmonary hilum is safe and effective. The key factors to prevent the complications include correct evaluation of lesion size, depth of needle penetration and the needle retention time before the operation.

Visualization tool-supported problem-based learning in clinical diagnostic expertise develop-ment / 中华医学教育探索杂志

Objective In problem-based learning, students are often found difficult to con-struct medical knowledge systematically and transfer knowledge to solve new problems. In face of this challenge, this study aims to investigate the effect of visualization tool-supported online problem-based learning on medical students' clinical diagnostic expertise development. Methods A controlled study was conducted and 52 medical students were randomly assigned into experimental group (using visual-ization tool-supported online PBL environment for learning) and control group (using online PBL envi-ronment for learning without visualization tool support). Participants were asked to complete the diag-nostic analysis of three kidney problems according to the requirements of the learning environments and to provide feedback of online learning experience afterwards. Paired-sample t test and one-way analysis of vonriance were used to analyze both group's case 1 and case 3 on line learing scores. Results The results revealed that the experimental group had significant improvement in online learning performance [case 1: (1.47 ±0.54), case 3: (2.14 ±0.55), P=0.015], while the control group had no significant improvement [case 1:(1.57±0.67), case 3:(1.66±0.49), P=0.234]. Early performance of online learning and group factor had interative effects (F=7.266, P=0.013). Conclusions The findings suggest that visualization tool-supported online PBL environment can facilitate medical student clinical diagnostic expertise development effectively.

Correlation between increased circulating endothelial progenitor cells and stage of non-Hodgkin lymphoma / 华中科技大学学报（医学）（英德文版）

This study aims to examine the levels of circulating endothelial progenitor cells (cEPCs) in the peripheral blood of patients with non-Hodgkin lymphoma (NHL) and their correlation with the tumor stage. Forty-one patients with biopsy-proven NHL and 16 healthy individuals were recruited. Peripheral blood mononuclear cells (PBMCs) were isolated by density gradient centrifugation, and cEPCs were characterized by triple staining using antibodies against CD133, CD34 and vascular endothelial growth factor receptor-2 (VEGFR-2, CD309) and quantified by flow cytometry. In NHL patients, the number of cEPCs was significantly greater than in control group (P=0.000). The cEPCs counts in patients with NHL of stage III-IV were significantly greater than in stage I-II (P=0.010). FACS analysis revealed that the number of cEPCs in NHL patients had no correlation with the gender (P=0.401) or the pathological category (P=0.852). It was suggested that the over-expression of cEPCs in NHL patients may serve as a novel biomarker for disease progression in NHL.

Correlation between increased circulating endothelial progenitor cells and stage of non-Hodgkin lymphoma / 华中科技大学学报（医学）（英德文版）

This study aims to examine the levels of circulating endothelial progenitor cells (cEPCs) in the peripheral blood of patients with non-Hodgkin lymphoma (NHL) and their correlation with the tumor stage. Forty-one patients with biopsy-proven NHL and 16 healthy individuals were recruited. Peripheral blood mononuclear cells (PBMCs) were isolated by density gradient centrifugation, and cEPCs were characterized by triple staining using antibodies against CD133, CD34 and vascular endothelial growth factor receptor-2 (VEGFR-2, CD309) and quantified by flow cytometry. In NHL patients, the number of cEPCs was significantly greater than in control group (P=0.000). The cEPCs counts in patients with NHL of stage III-IV were significantly greater than in stage I-II (P=0.010). FACS analysis revealed that the number of cEPCs in NHL patients had no correlation with the gender (P=0.401) or the pathological category (P=0.852). It was suggested that the over-expression of cEPCs in NHL patients may serve as a novel biomarker for disease progression in NHL.