Functional Characterization of the N-Acetylmuramyl-l-Alanine Amidase, Ami1, from Mycobacterium abscessus.

Peptidoglycan (PG) is made of a polymer of disaccharides organized as a three-dimensional mesh-like network connected together by peptidic cross-links. PG is a dynamic structure that is essential for resistance to environmental stressors. Remodeling of PG occurs throughout the bacterial life cycle, particularly during bacterial division and separation into daughter cells. Numerous autolysins with various substrate specificities participate in PG remodeling. Expression of these enzymes must be tightly regulated, as an excess of hydrolytic activity can be detrimental for the bacteria. In non-tuberculous mycobacteria such as Mycobacterium abscessus, the function of PG-modifying enzymes has been poorly investigated. In this study, we characterized the function of the PG amidase, Ami1 from M. abscessus. An ami1 deletion mutant was generated and the phenotypes of the mutant were evaluated with respect to susceptibility to antibiotics and virulence in human macrophages and zebrafish. The capacity of purified Ami1 to hydrolyze muramyl-dipeptide was demonstrated in vitro. In addition, the screening of a 9200 compounds library led to the selection of three compounds inhibiting Ami1 in vitro. We also report the structural characterization of Ami1 which, combined with in silico docking studies, allows us to propose a mode of action for these inhibitors

Symptoms and management of cow's milk allergy: perception and evidence

IntroductionThe diagnosis and management of cow's milk allergy (CMA) is a topic of debate and controversy. Our aim was to compare the opinions of expert groups from the Middle East (n = 14) and the European Society of Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) (n = 13).MethodsThese Expert groups voted on statements that were developed by the ESPGHAN group and published in a recent position paper. The voting outcome was compared.ResultsOverall, there was consensus amongst both groups of experts. Experts agreed that symptoms of crying, irritability and colic, as single manifestation, are not suggestive of CMA. They agreed that amino-acid based formula (AAF) should be reserved for severe cases (e.g., malnutrition and anaphylaxis) and that there is insufficient evidence to recommend a step-down approach. There was no unanimous consensus on the statement that a cow's milk based extensively hydrolysed formula (eHF) should be the first choice as a diagnostic elimination diet in mild/moderate cases. Although the statements regarding the role for hydrolysed rice formula as a diagnostic and therapeutic elimination diet were accepted, 3/27 disagreed. The votes regarding soy formula highlight the differences in opinion in the role of soy protein in CMA dietary treatment. Generally, soy-based formula is seldom available in the Middle-East region. All ESPGHAN experts agreed that there is insufficient evidence that the addition of probiotics, prebiotics and synbiotics increase the efficacy of elimination diets regarding CMA symptoms (despite other benefits such as decrease of infections and antibiotic intake), whereas 3/14 of the Middle East group thought there was sufficient evidence.DiscussionDifferences in voting are related to geographical, cultural and other conditions, such as cost and availability. This emphasizes the need to develop region-specific guidelines considering social and cultural conditions, and to perform further research in this area

Mucoceles gigantes: visão neurocirúrgica. Relato de dois casos Giant mucoceles: neurosurgical view. Report of two cases

São apresentados dois casos de mucocele gigante do seio frontal submetidos a tratamento cirúrgico. A manifestação clínica foi cefaléia de evolução prolongada, associada com protrusão unilateral do globo ocular de curta duração. Em ambos os casos foi realizada craniotomia frontal com remoção completa da lesão, reparação do soalho frontal com retalho pediculado de gálea e cranialização do seio frontal. No segundo caso, uma abordagem endoscópica intranasal foi combinada à abordagem externa no mesmo ato cirúrgico. Alguns aspectos abordando a etiologia, associação com outras afecções e tratamento cirúrgico são discutidos.<br>Two patients harboring giant frontal mucoceles are reported. In both cases complaints of chronic headaches and progressive unilateral proptosis were preponderant. Surgical treatment included a frontal craniotomy with excision of the lesion, skull base reinforcement with pedicled galea and wide opening of the frontal sinuses. In the second case an intranasal endoscopic approach was combined with craniotomy at the same surgical operative time. Some aspects regarding etiology, association with other diseases and some surgical aspects are discussed