Chemical synthesis of a synthetically useful L-galactosaminuronic acid building block.

Most bacterial cell surface glycans are structurally unique, and have been considered as ideal target molecules for the developments of detection and diagnosis techniques, as well as vaccines. Chemical synthesis has been a promising approach to prepare well-defined oligosaccharides, facilitating the structure-activity relationship exploration and biomedical applications of bacterial glycans. L-Galactosaminuronic acid is a rare sugar that has been only found in cell surface glycans of gram-negative bacteria. Here, an orthogonally protected L-galactosaminuronic acid building block was designed and chemically synthesized. A synthetic strategy based on glycal addition and TEMPO/BAIB-mediated C6 oxidation served well for the transformation of commercial L-galactose to the corresponding L-galactosaminuronic acid. Notably, the C6 oxidation of the allyl glycoside was more efficient than that of the selenoglycoside. In addition, a balance between the formation of allyl glycoside and the recovery of selenoglycoside was essential to improve efficiency of the NIS/TfOH-catalyzed allylation. This synthetically useful L-galactosaminuronic acid building block will provide a basis for the syntheses of complex bacterial glycans.

Prophylactic abdominal aortic balloon occlusion in patients with pernicious placenta previa during cesarean section: a systematic review and meta-analysis from randomized controlled trials.

PURPOSE: Pernicious placenta previa induces severe hemorrhage during cesarean section. Abdominal aorta balloon occlusion (AABO) is considered as an effective operation for patients with pernicious placenta previa. The aim of this study was to investigate the clinical application of abdominal aortic balloon occlusion in the placenta previa and cesarean section by systematic review and meta-analysis. METHODS: MEDLINE, EMBASE, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), WAN-FANG DATA and CQVIP were searched from inception to Jan. 15th, 2019. Operative time, intraoperative blood loss volume, postoperative hospitalization duration, intraoperative blood transfusion volume, hysterectomy rate, lower extremity thrombosis rate, ICU admission rate, adverse reaction rate, neonatal birth weight, Apgar 1-min and 5-min scores were regarded as the endpoints. Randomized controlled trials (RCT) were used for meta-analysis. RESULTS: Fourteen articles were retrieved from total 650 articles, and the results of meta-analysis showed that application of intraoperative AABO had the ability to reduce the operative time (WMD = - 16.581, 95% CI - 26.690 to - 6.472; P = 0.001), the intraoperative blood loss volume (WMD = - 1202.69, 95% CI - 1732.25 to - 673.12; P < 0.001), the intraoperative blood transfusion volume (WMD = - 1202.69, 95% CI - 1732.25 to - 673.12; P < 0.001). The hysterectomy rate (RR = 0.279, 95% CI 0.164-0.474; P < 0.001), postoperative hospitalization duration (WMD = - 1.423, 95% CI - 2.070 to - 0.776; P < 0.001) and the balloon preset time (WMD = - 13.793, 95% CI - 15.341 to - 12.244; P < 0.001; I2 = 0.0%) were also reduced in AABO group. CONCLUSIONS: Application of AABO in patients with pernicious placenta previa is safe and effective, which is worthy of clinical promotion.

Efficacy of telemedicine for thrombolytic therapy in acute ischemic stroke: a meta-analysis.

The aim of this study was to assess the benefits of telemedicine in the delivery of thrombolytic therapy for patients with acute ischemic stroke. We performed a meta-analysis using combinations of the following terms: telestroke, telemedicine, tissue plasminogen activator/t-PA, and acute ischemic stroke. The primary outcome was favorable outcome based on the modified Rankin score. Secondary outcomes were incidence of symptomatic intracranial hemorrhage and overall mortality. We found no significant difference in favorable outcome between the telemedicine and control groups, and no significant difference was found between these groups in the rate of symptomatic intracranial hemorrhage or overall mortality. Patients with acute ischemic stroke who were treated with intravenous thrombolysis had similar outcomes regardless of whether telemedicine was used or they were treated in-person at a medical facility. Telemedicine can be used to support hospitals with limited experience in administering thrombolytic therapy for stroke.

Soybean transcription factor GmMYBZ2 represses catharanthine biosynthesis in hairy roots of Catharanthus roseus.

Catharanthus roseus (L.) G. Don is a plant species known for its production of a variety of terpenoid indole alkaloids, many of which have pharmacological activities. Production of catharanthine in cell cultures or in hairy roots established by transformation with Agrobacterium rhizogenes is of interest because catharanthine can be chemically coupled to the abundant leaf alkaloid vindoline to form the valuable anticancer drug vinblastine. Here, we observed a high amount of catharanthine in hairy roots of C. roseus, established by infecting leaf explants with the A. rhizogenes >agropine-type A4 strain carrying plasmid pRi. T-DNA transfer from plasmid pRi into hairy roots was confirmed by PCR for the essential T-DNA genes rolA and rolB and the agropine synthesis gene ags. The results suggest that integration of T-DNA into the plant DNA plays a positive role on the catharanthine pathway in C. roseus hairy roots. Furthermore, co-transformation with the soybean transcription factor GmMYBZ2 indicated that GmMYBZ2 reduces the catharanthine production by alteration of expression of a number of genes linked to the pathway. Transcription levels of the zinc-finger transcription factor 1 gene ZCT1 were high, and the transcription levels of the anthranilate synthase gene ASα, the strictosidine synthase gene STR, and the key transcription factor gene octadecanoid-responsive Catharanthus APETALA2/ethylene response factor were low. In addition, GmMYBZ2 had a negative effect on the gene expression levels of A-type cyclin CYSA and B-type cyclin CYSB, which was correlated with a reduced growth rate of the hairy roots.

An approach to evaluate the reliability of hybridization-based and sequencing-based gene expression profiling technologies.

Hybridization-based and sequencing-based technologies have found a widespread application in gene expression profiling analysis but much ambiguity exists regarding their reliability. This study developed a framework based on three parameters: detection ability, repeatability, and accuracy to evaluate the reliability of gene expression profiling technologies. The fraction of coverage of detected transcript category, the degree of variance for the number of differentially expressed genes (DEGs), the consistency of DEG category, and suspected false discovery rate (sFDR) were first introduced as statistical indices. In order to validate the availability of these indices, based on the same RNA extract, the analysis was performed by comparing gene expression differences between wild-type and transgenic rice using deep sequencing and microarray. The results suggested that the parameters were available and showed advances in the determination of gene expression differences. Based on relative self-comparison design, suspected false positive genes were easily identified from all DEGs detected, which was difficult for quantitative real-time polymerase chain reaction (qRT-PCR) validation when the count of DEGs was enormous. In addition, sFDRs had advantages in the accuracy evaluation for previous datasets.