Botulinum toxin blocks mast cells and prevents rosacea like inflammation

Background

Rosacea is a chronic inflammatory skin condition whose etiology has been linked to mast cells and the antimicrobial peptide cathelicidin LL-37. Individuals with refractory disease have demonstrated clinical benefit with periodic injections of onabotulinum toxin, but the mechanism of action is unknown.

Phenotypic and genetic features of enteropathogenic Escherichia coli isolates from diarrheal children in the Ribeirão Preto metropolitan area,São Paulo State,Brazil

This study was designed to characterize a collection of 60 enteropathogenic Escherichia coli (EPEC) isolates from diarrheic feces of patients in the Ribeirão Preto metropolitan area regarding different phenotypic and molecular features. We examined antibiotic resistance profiles, occurrence of virulence factors‐encoding genes, intimin subtypes and the correlation of serotypes among typical (tEPEC) and atypical (aEPEC) EPEC isolates. The results demonstrated that atypical EPEC was more heterogeneous than typical EPEC concerning the characteristics investigated and 45.2% do not belong to classical EPEC serogroups. Intimin subtype β was the most frequent among the EPEC isolates (46.7%), being detected in both tEPEC and aEPEC. The majority of aEPEC isolates presented localized adherence‐like (LAL) pattern to HEp‐2 cells, although aEPEC isolates displaying diffuse adherence (DA) or non‐adherent were also detected. High prevalence of antimicrobial resistance was found for ampicillin, cephalothin, sulfonamide and tetracycline. In general, tEPEC isolates were more resistant to the antimicrobials tested than aEPEC isolates.     

Spread of an Enterococcus faecalis sequence type 6 (CC2) clone in patients undergoing selective decontamination of the digestive tract

Enterococcus faecalis (E. faecalis) is a common cause of nosocomial infection in immunocompromised patients. The presence and dissemination of high‐risk clonal complexes, such as CC2, is an ongoing problem in hospitals. The aim of this work was to characterize 24 E. faecalis isolates from ICU patients undergoing selective decontamination of the digestive tract (SDD) by phenotypical (antimicrobial susceptibility) and genotypical (presence of virulence genes, RAPD‐PCR and MLST) methods. Our results showed high prevalence of the ST6 E. faecalis clone (91.6%), especially adapted to the hospital environment, with a multidrug resistance pattern and a multitude of putative virulence genes. In addition, ST179 (4.2%) and ST191 (4.2%) were detected. By RAPD–PCR analysis, the 22 isolates identified as ST6 showed six different DNA patterns, while the two remaining isolates, ST179 and ST191, showed two additional profiles. CC2 is a known clonal complex with high adaptability to hospital environment and worldwide distribution. The high prevalence of the ST6 clone in the studied population could be related to the presence of gentamicin in the SDD mixture since most strains were gentamicin resistant. Consequently, strict surveillance should be applied for rapid detection and control of this clone to prevent future spread outside the ICU.     

狼毒二萜类化学成分及其药理作用研究进展

狼毒Euphorbiae Ebracteolatae Radix为大戟科(Euphorbiaceae)植物狼毒大戟Euphorbia fischeriana或月腺大戟E.ebracteolata的干燥根,是一种广泛应用,具有广阔开发前景的中药材。狼毒含有多种生物活性成分,其中二萜类化合物是最为重要的一个部分,主要包括松香烷型、巴豆烷型、海松烷型、玫瑰烷型、西松烷型、巨大戟烷型、贝壳杉烷型、阿替斯烷型8种类型,此外还有少量二萜二聚体及其他类型的二萜类化合物。狼毒二萜类化学成分具有显著的抗肿瘤、抗炎、抗菌、抗病毒等药理作用。对狼毒二萜类化学成分及其药理作用进行综述,以期为更好地开发狼毒资源及其临床应用提供参考。     

Novel phenotype of mouse spermatozoa following deletion of nine β-defensin genes

β-defensin peptides are a large family of antimicrobial peptides. Although they kill microbes in vitro and interact with immune cells, the precise role of these genes in vivo remains uncertain. Despite their inducible presence at mucosal surfaces, their main site of expression is the epididymis. Recent evidence suggests that a major function of these peptides is in sperm maturation. In addition to previous work suggesting this, work at the MRC Human Genetics Unit, Edinburgh, has shown that homozygous deletion of a cluster of nine β-defensin genes in the mouse results in profound male sterility. The spermatozoa derived from the mutants had reduced motility and increased fragility. Epididymal spermatozoa isolated from the cauda region of the homozygous mutants demonstrated precocious capacitation and increased spontaneous acrosome reactions compared with those from wild-types. Despite this, these mutant spermatozoa had reduced ability to bind to the zona pellucida of oocytes. Ultrastructural examination revealed a disintegration of the microtubule structure of mutant-derived spermatozoa isolated from the epididymal cauda region, but not from the caput. Consistent with premature acrosome reaction and hyperactivation, spermatozoa from mutant animals had significantly increased intracellular calcium content. This work demonstrates that in vivo β-defensins are essential for successful sperm maturation, and that their disruption alters intracellular calcium levels, which most likely leads to premature activation and spontaneous acrosome reactions that result in hyperactivation and loss of microtubule structure of the axoneme. Determining which of the nine genes are responsible for the phenotype and the relevance to human sperm function is important for future work on male infertility.     

Neutrophilic defensins penetrate the blood-brain barrier

Defensins are small, cationic, cyclic peptides that are abundantly stored in granules of neutrophils. Defensins non-specifically interact with membranes by forming weakly ion-selective pores. Here we demonstrate immunolocalization of defensin-secreting cells in human brain. Defensins, secreted by activated granulocytes, apparently are not prevented by the blood-brain barrier (BBB) from diffusing across cerebral endothelium to penetrate the neuropil for a considerable distance from the granulocyte. This is in contrast to other neutrophil proteins like the granuleassociated enzyme elastase or the cytosolic protein MRP-14, which are strictly localized to the cytoplasm or granules of neutrophils. Thus, defensins, known chemokinetic and chemotactic molecules, display a unique distribution at BBB sites. © 1995 Wiley-Liss, Inc.     

舍蝇抗菌肽的提取及其对肿瘤细胞生长的抑制作用

目的：研究含蝇抗菌肽的提取对肿瘤细胞生长的抑制作用；方法：对舍蝇幼虫采用针刺损伤及金黄色葡萄球菌感染诱导方法，并通过研磨、加热、阳离子交换柱层析及Sephadex G—50葡聚糖凝胶柱层析等步骤提取抗菌肽；结果：经SDS—PAGE电泳分离到2条带，分子量分别为4kD，9．6kD；结论：提取的舍蝇抗菌肽能有效地抑制人胃癌细胞MGC80—3和BGC—823，人乳腺癌细胞MCF—7及人肺癌细胞SPC—A—1的体外增殖，并且呈浓度依赖关系。