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Isothermal Titration Calorimetry (ITC) is widely employed to assess antimicrobial affinity for lipopolysaccharide (LPS); nevertheless, experiments are usually limited to commercially available-LPS chemotypes. Herein we show a method that uses Differential Scanning Calorimetry (DSC) to characterize homogeneity artificial vesicles of LPS (LPS-V) extracted from isogenic mutant bacterial strains before analyzing the antimicrobial binding by ITC. This method allows us to characterize the differences in the Polymyxin-B binding and gel to crystalline liquid (ß↔α) phase profiles of LPS-V made of LPS extracted from Escherichia coli isogenic mutant strains for the LPS biosynthesis pathway, allowing us to obtain the comparable data required for new antimicrobial discovery. A method for:•Obtaining LPS vesicles from isogenic mutant bacterial strains.•Characterize artificial LPS vesicles homogeneity.•Characterize antimicrobial binding to LPS.

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Malolactic fermentation (MLF) is responsible for the decarboxylation of l-malic into lactic acid in most red wines and some white wines. It reduces the acidity of wine, improves flavor complexity and microbiological stability. Despite its industrial interest, the MLF mechanism is not fully understood. The objective of this study was to provide new insights into the role of pH on the binding of malic acid to the malolactic enzyme (MLE) of Oenococcus oeni. To this end, sequence similarity networks and phylogenetic analysis were used to generate an MLE homology model, which was further refined by molecular dynamics simulations. The resulting model, together with quantum polarized ligand docking (QPLD), was used to describe the MLE binding pocket and pose of l-malic acid (MAL) and its l-malate (-1) and (-2) protonation states (MAL- and MAL2-, respectively). MAL2- has the lowest ∆Gbinding, followed by MAL- and MAL, with values of -23.8, -19.6, and -14.6 kJ/mol, respectively, consistent with those obtained by isothermal calorimetry thermodynamic (ITC) assays. Furthermore, molecular dynamics and MM/GBSA results suggest that only MAL2- displays an extended open conformation at the binding pocket, satisfying the geometrical requirements for Mn2+ coordination, a critical component of MLE activity. These results are consistent with the intracellular pH conditions of O. oeni cells-ranging from pH 5.8 to 6.1-where the enzymatic decarboxylation of malate occurs.

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BACKGROUND: There is a paucity of information about the epidemiology of acute renal failure in Chile. AIM: To perform a prospective multicentric survey of severe acute renal failure in Chile. MATERIAL AND METHODS: All patients admitted to ten hospitals in Metropolitan Santiago, during a period of six months with severe acute renal failure, were studied. The criteria for severity was the requirement of renal replacement therapy. All patients information was gathered in special forms and the type of renal replacement therapy and evolution was registeres. RESULTS: One hundred fourteen patients were studied (65 males, age range 18 to 87 years). The calculated incidence of acute renal failure was 1.03 cases per 1000 hospital discharges. The onset was nosocomial in 79 subjects (69%) and community acquired in the rest. Renal failure was oliguric in 64 cases (56%) and in 60% of patients it had two or more causative factors. Sepsis, isolated or combined with other causes, was present in 51 of patients. Other causes included ischemia in 47%, surgery in 26%, exogenous toxicity in 25%, endocenous toxicity in 11%, acute glomerular damage in 6% and obstructive uropathy in 6%. Cardiac surgery was responsible for 47% of post operative cases of acute renal failure. Intermittent conventional hemodialysis, continuous renal replacement techniques and daily prolonged hemodialysis were used in 66%, 29% and 2% of patients, respectively. Overall mortality was 45% and it was higher in oliguric patients. Gender, age, cause or the type of therapy did not influence survival. Nine percent of surviving patients had some degree of kidney dysfunction at discharge. CONCLUSIONS: There is still a great space for prevention of severe acute renal failure in Chile, considering the main etiologies found in this study.

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Los accidentes constituyen un acontecimiento traumático y pueden provocar repercusiones psíquicas, entre ellas un trastorno de adaptación. Objetivo: estudiar las características clínicas y la evolución de pacientes con un trastorno de adaptación con síntomas de estrés postraumático (TAD), cuadro que no alcanza a cumplir los criterios diagnósticos para trastorno agudo de estrés o trastorno de estrés postraumático. Metodología: estudio retrospectivo de fichas clínicas de accidentados del trabajao (1996-1998), utilizando criterios diagnósticos de la CIE-10 y un instrumento ad hoc para recoger la información. Se efectuó análisis estadístico con el programa computacional Epi Info 6,04. Resultados: la muestra estuvo constituida por 141 pacientes (54 por ciento hombres), de los cuales el 77,3 por ciento fue derivado a consultar en psiquiatría antes de 30 días de ocurrido el accidente. El tipo de accidente fue una amenaza o ataque intencional (39,3 por ciento), accidente de tránsito (26,4 por ciento) y accidentes en el lugar de trabajo (34,3 por ciento). Los síntomas predominantes fueron los de tipo invasor (95,0 por ciento), ansiedad (93,6 por ciento) y trastornos del sueño (87,9 por ciento). El tratamiento combinado de psicofármacos y psicoterapia duró 85 días y el 62,4 por ciento de los pacientes requirió de reposo médico (en promedio 57,6 días). El 82,3 por ciento de la muestra egresó con el mismo diagnóstico. Los factores que influyeron en una derivación más precoz fueron el tipo de accidente (asalto/violación), los síntomas invasores y los trastornos del sueño. Conclusiones: el diagnóstico de TAD constituye un constructo operacional que ayuda a una derivación más precoz y a un menor tiempo de tratamiento

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