Hibridização in situ fluorescente: princípios básicos e perspectivas para o diagnóstico de doenças infecciosas em medicina veterinária

Case report: acute myocarditis complicated with persistent complete heart block: a clinical dilemma when myocardial inflammation remains

Background

Atrioventricular conduction abnormalities due to acute myocarditis are typically transient and do not require ventricular pacing beyond the acute phase of myocardial inflammation. Notwithstanding, selective injury and necrosis of the heart's conduction system may lead to persistent complete heart block (CHB) requiring device implantation.

Case summary

We report the case of a 23-year-old man with acute lymphocytic myocarditis complicated by cardiogenic shock, cardiac arrest due to ventricular fibrillation, and persistent CHB. Endomyocardial biopsy (EMB) showed signs of subacute myocarditis, with no evidence of granulomas or giant cells, nor criteria for eosinophilic myocarditis. Aetiological work-up found serological evidence of previous Epstein-Barr virus (EBV) infection; Borrelia burgdorferi serology for Lyme disease was negative. The real time-polymerase chain reaction (RT-PCR) of the EMB was positive for the presence of EBV DNA, but in situ hybridization for viral ribosomal RNA (rRNA) was negative. The patient progressed favourably, and left ventricle ejection fraction recovered 2 weeks after initial presentation. However, CHB persisted for more than 3 weeks, and the patient underwent definitive pacemaker implantation with left bundle branch pacing.

Discussion

Persistent CHB after acute myocarditis is generally considered unlikely, but in rare circumstances the damage portended by inflammation may be irreversible. Besides the play of chance, possible mechanisms behind the apparent predilection for the conduction system of the myocardium warrant further research.

Biosurfactants during in situ bioremediation: factors that influence the production and challenges in evalution

Research on the influence of biosurfactants on the efficiency of in situ bioremediation of contaminated soil is continuously growing. Despite the constant progress in understanding the mechanisms involved in the effects of biosurfactants, there are still many factors that are not sufficiently elucidated. There is a lack of research on autochthonous or exogenous microbial metabolism when biostimulation or bioaugmentation is carried out to produce biosurfactants at contaminated sites. In addition, studies on the application of techniques that measure the biosurfactants produced in situ are needed. This is important because, although the positive influence of biosurfactants is often reported, there are also studies where no effect or negative effects have been observed. This review aimed to examine some studies on factors that can improve the production of biosurfactants in soils during in situ bioremediation. Moreover, this work reviews the methodologies that can be used for measuring the production of these biocomposts. We reviewed studies on the potential of biosurfactants to improve the bioremediation of hydrocarbons, as well as the limitations of methods for the production of these biomolecules by microorganisms in soil.