Anti-salmonella properties of kefir yeast isolates: An in vitro screening for potential infection control

The rise of antibiotic resistance has increased the need for alternative ways of preventing and treating enteropathogenic bacterial infection. Various probiotic bacteria have been used in animal and human. However, Saccharomyces boulardii is the only yeast currently used in humans as probiotic. There is scarce research conducted on yeast species commonly found in kefir despite its claimed potential preventative and curative effects. This work focused on adhesion properties, and antibacterial metabolites produced by Kluyveromyces lactis and Saccharomyces unisporus isolated from traditional kefir grains compared to Saccharomyces boulardii strains. Adhesion and sedimentation assay, slide agglutination, microscopy and turbidimetry assay were used to analyze adhesion of Salmonella Arizonae and Salmonella Typhimurium onto yeast cells. Salmonella growth inhibition due to the antimicrobial metabolites produced by yeasts in killer toxin medium was analyzed by slab on the lawn, turbidimetry, tube dilution and solid agar plating assays. Alcohol and antimicrobial proteins production by yeasts in killer toxin medium were analyzed using gas chromatography and shotgun proteomics, respectively. Salmonella adhered onto viable and non-viable yeast isolates cell wall. Adhesion was visualized using scanning electron microscope. Yeasts-fermented killer toxin medium showed Salmonella growth inhibition. The highest alcohol concentration detected was 1.55%, and proteins with known antimicrobial properties including cathelicidin, xanthine dehydrogenase, mucin-1, lactadherin, lactoperoxidase, serum amyloid A protein and lactotransferrin were detected in yeasts fermented killer medium. These proteins are suggested to be responsible for the observed growth inhibition effect of yeasts-fermented killer toxin medium. Kluyveromyces lactis and Saccharomyces unisporus have anti-salmonella effect comparable to Saccharomyces boulardii strains, and therefore have potential to control Salmonella infection.     

Dietary practices,site-specific tumors,and age-at-death relationships

When rats are given freedom of dietary choice, the quantity and composition of the diet selected varies from animal to animal, but the risk to the individual of developing a variety of neoplasms is greatly increased over that of rats fed fixed diets. The increase in frequency of tumors cannot be explained on the basis of the amount or the composition of the diet selected. However, the application of “variable selection” statistical procedures shows that there are combinations of temporal-specific interacting dietary and dietary-dependent variables that are closely linked with cancer mortality. The multi-variable statistical model for animals dying with one type of tumor is not applicable to those dying with tumors of other types or sites. In every case, the only data required to characterize the dates of death of tumor-bearing individuals are those describing the dietary practices and growth responses prior to maturity. The model for animals with pancreatic tumors is used to illustrate the extent to which dietary practices of early life are linked with the animals’ survival.     

Clusterings should not be compared by visual inspection: response to Gagné & Proulx

In Heikinheimo et al . ( Journal of Biogeography , 2007, 34 , 1053–1064) we used clustering to analyse European land mammal fauna. Gagné & Proulx criticized our choice of the Euclidean distance measure in the analysis, and advocated the use of the Hellinger distance measure, claiming that this leads to very different clustering results. The criticism fails to take into account the probabilistic nature of the methods used and the fact that in this case the similarity measures correlate strongly. Gagné & Proulx used subjective inspection as the criterion of similarity between clusterings. We show that this is insufficient and misleading. Namely, owing to the local minimum problem, two clustering runs rarely give identical results. In the case of our study, the measured similarity (using the kappa statistic) between the Euclidean- and Hellinger-based clusterings is roughly equal to the similarity between two clusterings that both use the Hellinger distance but different random initialization points.     

Rational Design of Novel Phosphoinositide 3‐Kinase Gamma (PI3Kγ) Selective Inhibitors: A Computational Investigation Integrating 3D‐QSAR,Molecular Docking and Molecular Dynamics Simulation

Phosphoinositide 3‐kinase gamma (PI3Kγ) draws an increasing attention due to its link with deadly cancer, chronic inflammation and allergy. But the development of PI3Kγ selective inhibitors is still a challenging endeavor because of the high sequence homology with the other PI3K isoforms. In order to acquire valuable information about the interaction mechanism between potent inhibitors and PI3Kγ, a series of PI3Kγ isoform‐selective inhibitors were analyzed by a systematic computational method, combining 3D‐QSAR, molecular docking, molecular dynamic (MD) simulations, free energy calculations and decomposition. The general structure–activity relationships were revealed and some key residues relating to selectivity and high activity were highlighted. It provides precious guidance for rational virtual screening, modification and design of selective PI3Kγ inhibitors. Finally, ten novel inhibitors were optimized and P10 showed satisfactory predicted bioactivity, demonstrating the feasibility to develop potent PI3Kγ inhibitors through this computational modeling and optimization.     

内镜黏膜下剥离术和挖除术治疗上消化道肿瘤的疗效及安全性分析

目的:分析内镜黏膜下剥离术(ESD)和黏膜下挖除术(ESE)治疗上消化道肿瘤的疗效及安全性。方法:回顾性分析2017年1月至2019年4月我院消化内科接受ESD或ESE治疗的68例上消化道肿瘤住院患者的临床资料,收集患者基础疾病、手术时间、病变部位大小、整块切除率、并发症等资料,同时采用Logistic回归分析对术中穿孔进行危险因素分析。结果:64例患者完整切除瘤体(94.12%),肿瘤平均直径(16.98±8.29)mm。食管病灶病理类型以高级别上皮内瘤变为主,有15例(22.06%);胃部病灶分布以胃体、胃底和胃窦居多,分别有18例(26.47%)、16例(23.53%)和12例(17.65%),病理类型以间质瘤最多,占36.76%;11例患者发生并发症(16.18%),4例患者出现术后出血(5.88%),经过内镜下止血后好转,8例患术中穿孔(11.76%),均行内镜下尼龙绳联合钛夹行荷包缝合,其中1例患者术中穿孔合并术后迟发性出血;病灶最大直径(≥25 mm,P=0.036)和病灶部位(胃底,P=0.015)是导致ESD或ESE术中穿孔的独立危险因素。结论:ESD和ESE治疗上消化道肿瘤安全有效,但需注意病灶大小和胃底病变,因其是导致术中穿孔的独立危险因素。     

两种内镜手术对消化道神经内分泌肿瘤的切除效果及安全性评价

目的:探讨内镜下两种手术方法对消化道神经内分泌肿瘤的切除效果和安全性。方法:选取64例消化道神经内分泌肿瘤患者,随机分为A组和B组,每组各32例。A组接受内镜下黏膜切除术,B组接受内镜下黏膜剥离术。分析和比较两组所切除组织的病理学检查结果、手术时间、切除肿瘤的直径和厚度、治疗费用、住院时间、肿瘤完全切除率、垂直切缘阴性率以及并发症的发生率。结果:A组的手术时间为(8.95±1.63) min,治疗费用为(2127.70±468.31)元,均显著少于B组(P0.05);两组患者切除肿瘤直径和厚度、住院时间、垂直切缘阴性率对比差异均没有统计学意义(P0.05);B组的肿瘤完全切除率为93.75%,显著高于A组(P0.05);A组并发症发生率为3.13%,显著低于B组(P0.05)。结论:两种内镜下手术方式均可有效清除消化道神经内分泌肿瘤病灶。内镜下黏膜切除术的手术时间、费用及并发症的发生率更少低,而内镜下黏膜剥离术能够更彻底地清除肿瘤组织。     

PKD1基因与抑癌基因P53多态性与非综合征性唇腭裂的关联研究

目的:探讨多囊性肾病基因1(polystic kidney disease,PKD1)多态位点rs8049367与抑癌基因P53(anti-oncogene P53)多态位点rs4791774单核苷酸多态性与中国北方人群非综合征性唇腭裂(NSCL/P)的相关性。方法:运用聚合酶链式反应-连接酶检测反应(PCR-LDR)的检测方法,对602例NSCL/P患者和510例对照人群的PKD1基因的rs8049367位点和抑癌基因P53的rs4791774位点进行基因分型。利用SPSS12.0软件分析PKD1基因,抑癌基因P53多态性与NSCL/P的相关性。结果:rs8049367位点和rs4791774位点基因型及基因频率在两组的分布中差异无统计学意义(P0.05)。结论:PKD1基因的rs8049367位点和抑癌基因P53的rs4791774位点单核苷酸多态性可能与中国北方人群非综合征性唇腭裂的发生无相关性。