Bombas de expulsión multidrogas en Acinetobacter baumannii y resistencia a antimicrobianos / Multi-drug efflux pumps and antibiotic resistance in Acinetobacter baumannii

Los sistemas multidrogas bacterianos contribuyen al desarrollo del fenotipo de multi-resistencia presentado por cepas de Acinetobacter baumannü, patógeno intrahospi-talario, que durante los últimos años ha incrementado su importancia por la creciente resistencia a carbapenémicos. El fenotipo de multi-resistencia está otorgado por la combinación de varios mecanismos de resistencia entre los cuales se encuentran estos sistemas de bombas de expulsión. El sistema multidroga AdeABC se ha detectado en muchas de estas cepas multi-resistentes de A. baumannü y, se ha relacionado con resistencia a diversos grupos de antimicrobianos, incluidos tigeciclina y meropenem. La inhibición de dichos sistemas multidrogas permitiría aumentar la eficacia de la terapia antimicrobiana. La siguiente revisión se enfoca en las bombas de expulsión multidrogas presentes en A. baumannü, con particular énfasis en el sistema AdeABC.

Bacterial multi-drugs systems contribute to the development of multi-resistance patterns of Acinetobacter baumannii, a nosocomial pathogen of increasing importance due to its emerging resistance to carbapenems. The multi-resistance phenomena is generated by a combination of mechanisms, one of which the efflux pump system. Many of these multiresistant isolates of A. baumannii harbor genes for the AdeABC multi-drug efflux system, related with resistance to various groups of antibacterial agents, including tygecicline and meropenem. Inhibition of these systems would allow to increase the efficacy of this antimicrobial. This review focuses on the multi-drug efflux pump system oí A. baumanni with special emphasis in the AdeABC system.

Amyloid-beta-peptide reduces copper(II) to copper(I) independent of its aggregation state

Alzheimer's disease (AD) is characterized by the deposition of amyloid beta-peptide (A beta) and neuronal degeneration in brain regions involved in learning and memory. One of the leading etiologic hypotheses regarding AD is the involvement of free radical-mediated oxidative stress in neuronal degeneration. Recent evidence suggests that metals concentrated in amyloid deposits may contribute to the oxidative insults observed in AD-affected brains. We hypothesized that A beta peptide in the presence of copper enhances its neurotoxicity generating free radicals via copper reduction. In the present study, we have examined the effect of the aggregation state of amyloid-beta-peptide on copper reduction. In independent experiments we measured the copper-reducing ability of soluble and fibrillar A beta(1-40) forms by bathocuproine assays. As it was previously observed for the amyloid precursor protein (APP), the A beta peptide showed copper-reducing ability. The capacity of A beta to reduce copper was independent of the aggregation state. Finally, the A beta peptide derived from the human sequence has a greater effect than the A beta peptide derived from the rat sequence, suggesting that histidine 13 may play a role in copper reduction. In agreement with this possibility, the A beta peptide reduces less copper in the presence of exogenous histidine.

Evaluación radioisotópica del efecto del ácido alginico/antiácido en la prevención del reflujo gastroesofágico (RGE) patológico / Radioisotopic evaluation of alginic acid/antacid effect in the pathologic gastroesophageal reflux (GER) prevention

En este estudio fueron evaluados prospectivamente los efectos de un compuesto Antiácido/Acido Algínico (Batynid R) mediante técnicas radiosotópicas. Los pacientes fueron divididos en 2 grupos: esofagitis moderada, 13 pacientes y esofagitis serias, 13 pacientes. El estudio isotópico fue realizado antes y posterior a la ingesta del compuesto evaluando la duración, severidad y n§ de episodios de reflujo. Los resultados no mostraron diferencias significativas comparando el reflujo gástrico antes y después del BATYNID R, en ambos grupos de pacientes, considerando todos los pacientes estudiados

Reconstrucción mandibular post hemimandibulectomia. Presentación caso clinico / [Mandibular reconstruction after hemimandibulectomy. Report of a clinical case]

Reconstruction of the mandible with iliac crest bone graft has been reported since early 1900’S. The series go from one to 160 cases published. This article shows the way we approached de reconstruction of a patient who came with an hemimandibulectomy due to osteosarcoma.