Experimental and finite element analysis for prediction of kidney injury under blunt impact

Kidneys are third most injured organs in abdominal trauma after liver and spleen; this study therefore is an attempt to understand the behaviour of kidneys under blunt trauma. Dynamic impact tests were performed on 20 fresh porcine kidneys to study the injury propagation in the organ, and the acceleration of the impactor was measured. A kidney model was developed with structural details like capsule and cortex. The kidney cortex was modelled with solid hexahedral elements and the capsule was modelled with quadratic shell elements. The material models for the capsule and cortex were used from the experimental data reported in our previous study. The developed model was calibrated using previous and current experimental results to reproduce the injuries of the organ in terms of acceleration of the impactor, and the injuries sustained by the organ during the experiments. The developed kidney model is observed to be robust and can be integrated with the available human body finite element models to simulate accidents and to predict or simulate injuries.     

Complete 6-Deoxy-D-altro-heptose Biosynthesis Pathway from Campylobacter jejuni: MORE COMPLEX THAN ANTICIPATED

The Campylobacter jejuni capsule is important for colonization and virulence in various infection models. In most strains, the capsule includes a modified heptose whose biological role and biosynthetic pathway are unknown. To decipher the biosynthesis pathway for the 6-deoxy-d-altro-heptose of strain 81-176, we previously showed that the 4,6-dehydratase WcbK and the reductase WcaG generated GDP-6-deoxy-d-manno-heptose, but the C3 epimerase necessary to form GDP-6-deoxy-d-altro-heptose was not identified. Herein, we characterized the putative C3/C5 epimerase Cjj1430 and C3/C5 epimerase/C4 reductase Cjj1427 from the capsular cluster. We demonstrate that GDP-6-deoxy-d-altro-heptose biosynthesis is more complex than anticipated and requires the sequential action of WcbK, Cjj1430, and Cjj1427. We show that Cjj1430 serves as C3 epimerase devoid of C5 epimerization activity and that Cjj1427 has no epimerization activity and only serves as a reductase to produce GDP-6-deoxy-d-altro-heptose. Cjj1430 and Cjj1427 are the only members of the C3/C5 epimerases and C3/C5 epimerase/C4 reductase families shown to have activity on a heptose substrate and to exhibit only one of their two to three potential activities, respectively. Furthermore, we show that although the reductase WcaG is not part of the main pathway, its presence and its product affect the outcome of the pathway in a complex regulatory loop involving Cjj1427. This work provides the grounds for the elucidation of similar pathways found in other C. jejuni strains and other pathogens. It provides new molecular tools for the synthesis of carbohydrate antigens useful for vaccination and for the screening of enzymatic inhibitors that may have antibacterial effects.     

NeuA O-acetylesterase activity is specific for CMP-activated O-acetyl sialic acid in Streptococcus suis serotype 2

Several bacteria causing meningitis, such as Escherichia coli K1, Streptococcus suis, Neisseria meningitidis, and group B Streptococci (GBS), produce sialic acid (Neu5Ac)-containing capsular polysaccharide (CPS). Biosynthesis of the Neu5Ac-containing CPS requires CMP-Neu5Ac as substrate, which is synthesized by CMP-Neu5Ac synthetase from CTP and Neu5Ac. In E. coli or GBS, the NeuA protein encoded by the neuA gene has been known encoding a bifunctional enzyme that possesses both CMP-Neu5Ac synthetase and O-acetylesterase activity. In this report, we found that the S. suis NeuA (SsNeuA) was also a bifunctional CMP-Neu5Ac synthetase/O-acetylesterase. Biochemical analyses revealed that the SsNeuA strictly de-O-acetylated CMP-O-acetyl-Neu5Ac, whereas the E. coli NeuA (EcNeuA) preferentially de-O-acetylated CMP-O-acetyl-Neu5Ac. E. coli devoid of NeuA O-acetylesterase activity was unable to produce capsule and only CMP-Neu5Ac synthetase activity of the EcNeuA or SsNeuA could not restore its ability to produce capsule. These results suggest that the O-acetylesterase is essential for the synthesis of capsular Neu5Ac in E. coli, probably in S. suis and GBS as well. Our findings are key to understanding the biosynthesis of capsular Neu5Ac in E. coli, S. suis and GBS.     

Comparison of Predicted Epimerases and Reductases of the Campylobacter jejuni d-altro- and l-gluco-Heptose Synthesis Pathways

Uniquely modified heptoses found in surface carbohydrates of bacterial pathogens are potential therapeutic targets against such pathogens. Our recent biochemical characterization of the GDP-6-deoxy-d-manno- and GDP-6-deoxy-d-altro-heptose biosynthesis pathways has provided the foundation for elucidation of the more complex l-gluco-heptose synthesis pathway of Campylobacter jejuni strain NCTC 11168. In this work we use GDP-4-keto,6-deoxy-d-lyxo-heptose as a surrogate substrate to characterize three enzymes predicted to be involved in this pathway: WcaG_NCTC (also known as Cj1427), MlghB (Cj1430), and MlghC (Cj1428). We compare them with homologues involved in d-altro-heptose production: WcaG₈₁₁₇₆ (formerly WcaG), DdahB (Cjj1430), and DdahC (Cjj1427). We show that despite high levels of similarity, the enzymes have pathway-specific catalytic activities and substrate specificities. MlghB forms three products via C3 and C5 epimerization activities, whereas its DdahB homologue only had C3 epimerase activity along its cognate pathway. MlghC is specific for the double C3/C5 epimer generated by MlghB and produces l-gluco-heptose via stereospecific C4 reductase activity. In contrast, its homologue DdahC only uses the C3 epimer to yield d-altro-heptose via C4 reduction. Finally, we show that WcaG_NCTC is not necessary for l-gluco-heptose synthesis and does not affect its production by MlghB and MlghC, in contrast to its homologue WcaG₈₁₁₇₆, that has regulatory activity on d-altro-heptose synthesis. These studies expand our fundamental understanding of heptose modification, provide new glycobiology tools to synthesize novel heptose derivatives with biomedical applications, and provide a foundation for the structure function analysis of these enzymes.     

复方谷氨酰胺联合双歧杆菌三联活菌胶囊治疗腹泻型肠易激综合征患者的临床疗效

摘要 目的：研究复方谷氨酰胺以及双歧杆菌三联活菌胶囊联用治疗腹泻型肠易激综合征患者的临床疗效。方法：选择2016年1月～2020年2月安徽省濉溪县医院收治的81例腹泻型肠易激综合征患者,将其随机分为两组。对照组41例患者仅口服420 mg的双歧杆菌三联活菌胶囊,每天3次;观察组40例患者加用500 mg的复方谷氨酰胺,每天3次。检测两组治疗前后的血清内毒素、二胺氧化酶活性及D-乳酸水平;血清白介素-6(Interleukin -6,IL-6)、肿瘤坏死因子-α(Tumor necrosis factor alpha,TNF-α)、白介素-8(Interleukin -8,IL-8)、高敏C反应蛋白(High sensitive C reactive protein,hs-CRP)水平;血浆生长抑素和血管活性肠肽水平并比较治疗后临床疗效及治疗过程中不良反应的发生情况。结果：治疗后,观察组的有效率为97.5%,明显高于对照组(75.61%,P<0.05);两组的血清内毒素、二胺氧化酶活性及D-乳酸、IL-6、TNF-α、IL-8、hs-CRP水平、血浆生长抑素和血管活性肠肽水平均较治疗前明显降低(P<0.05),且观察组以上指标均明显低于对照组(P<0.05)。观察组治疗期间的有2例嗜睡、头晕、乏力不适,发生率为5.00 %,对照组有2例头晕,1例头痛、口干,发生率为7.32 %,两组对比无统计学意义（P>0.05）。结论：复方谷氨酰胺联合双歧杆菌三联活菌胶囊治疗腹泻型肠易激综合征患者的临床效果明显优于单用双歧杆菌三联活菌胶囊治疗,其可有效修复肠黏膜屏障损伤,可能与其减轻炎症反应并改善胃肠激素水平有关。     

Developing hydroxypropyl methylcellulose/hydroxypropyl starch blends for use as capsule materials

Blends of hydroxypropyl methylcellulose (HPMC) with up to 70% hydroxypropyl starch (HPS) were developed for use as hard capsule materials. Polyethylene glycol (PEG) was used as both a plasticizer and a compatibilizer in the blends. In order to prepare hard capsules for pharmaceutical application using the well-established method of dipping stainless steel mold pins into solution then drying at certain temperature, equilibrated solutions with higher solids concentration (20%) were investigated and developed. The solutions, films and capsules of the different HPMC/HPS blends were characterized by viscosity, transparency, tensile testing, water contact angle, SEM, as well as FTIR. The results showed that the blend system is immiscible but compatible in certain degree, especially after adding PEG. The hydroxypropylene groups grafted onto both cellulose and starch improved the compatibility between the HPMC and the modified starch. The higher viscosity of starch at lower temperature improved the viscosity balance of the system, which enlarged the operation window for the dipping–drying technique. The PEG increased the transparency and toughness of the various blends. By optimizing temperature and incubation time to control viscosity, capsules of various blends were successfully developed.     

Assembled capsules transportation driven by motor proteins

An active biomimetic system by integrating kinesin motor, microtubule, and man-made biomimetic microcapsule has been constructed. Biomimetic microcapsules were fabricated by using the layer-by-layer technique and could serve as cargos in this active biomimetic system. Both of the hollow and filled capsules as cargos can be transported by kinesin motors along microtubules. It may help to create kinesin-powered complex hybrid micro- and nanodevices.     

Capsule walls as barriers to oxygen availability: Implications for the development of brooded embryos by the estuarine gastropod Crepipatella dilatata (Calyptraeidae)

Encapsulation of developing embryos imposes potential restrictions, because the capsule wall must allow for adequate inward diffusion of oxygen and for increased diffusion of oxygen as metabolic demand increases with continued development. Samples of egg capsules from the gastropod Crepipatella dilatata were used to document surface characteristics, composition of the different capsule wall layers, and alterations in wall thickness during development. The diffusion coefficient and capsule wall permeability were determined experimentally for capsules containing embryos at different developmental stages. We also determined oxygen consumption rates for various embryonic stages and for nurse eggs, which provide food for embryos during development. The capsule wall of C. dilatata possesses 2 differentiated layers: the external capsular wall (ECW) and the internal capsular wall (ICW). The ECW is compact and fibrous, features that remain invariable during development, and lacks surface features that might make some portions of the capsule wall more permeable to oxygen than others. On the other hand, the ICW is initially spongy and thick, but significantly decreases in thickness over time, particularly before the embryos begin feeding on nurse eggs. Although the capsule wall is a serious barrier to diffusion, permeability to oxygen increases over time by 112% due to the dramatic thinning of the inner capsule wall layer. Nurse eggs consume oxygen but at very low rates, supporting the idea that they correspond to living embryonic cells that have stopped their development. Respiration measurements indicated that embryos are initially supplied with enough oxygen within the egg capsules to carry out the activities characteristic of embryogenesis, even though the capsular walls show their maximum thickness and lowest permeability at this time. However, as the embryo develops its velum and becomes more active, capsule wall thickness decreases and capsule permeability to oxygen increases. Correspondingly, the oxygen demands of metamorphosed but still encapsulated specimens are approximately 135% higher than those of pre-metamorphosed sibling embryos.     

胰岛素联合百令胶囊对早期糖尿病肾病患者临床疗效的影响

目的:探讨胰岛素联合百令胶囊对早期糖尿病肾病患者临床疗效的影响。方法:选取前来我院就诊的已确诊的早期糖尿病肾病患者70例,随机分为对照组和治疗组,每组35例。对照组给予门冬胰岛素治疗;治疗组在对照组基础上联合百令胶囊。比较治疗前后两组患者的血糖、尿白蛋白排泄率(UAER)、24 h尿蛋白定量、β2—微球蛋白(β2-MG)、血肌酐(SCr)、尿素氮(BUN)、T淋巴细胞(CD68)水平的变化情况,记录分析两组患者的临床疗效。结果:治疗组总有效率明显高于对照组(P0.05)。治疗后,两组患者血糖、UAER、24h尿蛋白定量、β2-MG、SCr、BUN、CD68水平均较治疗前显著降低,且治疗组低于对照组(P0.05)。结论:胰岛素和百令胶囊的联合应用能有效控制早期糖尿病肾病患者的血糖水平,减少肾脏损伤,缓解临床症状,提高临床疗效。