The burden of calcific aortic stenosis: what's behind?

In Western countries, calcific aortic valve stenosis (CAS) is widely common, representing the third cause of death among cardiovascular diseases (CVD). The burden of CAS is high, with an increasing prevalence rate related to age. An efficient medical treatment, according to guidelines, lacks to prevent the development and to reduce the progression of CAS. In this context, due to the aging population and the lack of effective medical management, the prevalence is expected to double-triple within the next decades. In our review, we aim to provide an overview of the underlying mechanisms of pathogenesis and the current state of the art regarding pathophysiological insights and novel potential therapeutic targets.

Increased incidence of postmyocardial infarction ventricular septal defects during Covid-19 pandemic: A case series.

INTRODUCTION: Ventricular septal defect (VSD) is one of the mechanical complications of acute myocardial infarction (MI), whose incidence has been decreasing throughout the years because of the emergence of different reperfusion therapy strategies. METHODS: We present a series of seven patients who underwent surgery for post-MI VSD repair in our institution in the period between March 2020 and June 2021. DISCUSSION: During the recent SARS-COV2 pandemic, time to hospital admission increased due to patients being overcautious out of fear of exposing themselves to COVID-19. The increased time to hospital admission, with associated late reperfusion therapy and delayed PCI, is closely related to an augmented incidence of post-myocardial infarction mechanical complications such as ventricular septal defects. For this reason, we witnessed an increase in the incidence of post-MI VSD. CONCLUSION: Fear of exposure to SARS-COV2 in the medical environment was a major source of concern for all our patients. The target of hospital policy should be to reassure patients of freedom from COVID in the emergency department and cardiac wards in order to prevent such dreadful complications.

Hardware in the medial malleolus: is it intra-articular?

This paper is a radiographic approach to ascertain if the hardware at the medial malleolus is intra-articular. A human tibia was removed from a skeleton and pins were placed in the medial malleolus representing pins that would be intra- and extra-articular (in the mortise). Radiographs were obtained at precise rotation intervals. Those pins that were placed intra-articularly could not be made to appear otherwise. The pin that was placed extra-articularly was visualized on a single view to be extra-articular. Therefore, if hardware can be demonstrated to be extra-articular on any one view then it is not intra-articular.

Group II intron self-splicing. Alternative reaction conditions yield novel products.

Reaction parameters were modified to enhance the in vitro reaction rate and to reveal partial and novel reactions of the group II intron 5g of the mitochondrial gene from Saccharomyces cerevisiae encoding cytochrome c oxidase subunit I. One alteration yields separate 5'- and 3'-exons plus linear excised intron as the main products. A linear reaction intermediate, containing intron and 3'-exon, and products resulting from cleavages at two unexpected sites were identified. Spliced exon "reopening," a novel reaction between excised intron and spliced exons, appears responsible for separate 5'- and 3'-exon products.

Modification of the vitamin K-dependent carboxylase assay.

Methods are presented that describe alternative protocols for the isolation of rat liver microsomes containing the vitamin K-dependent carboxylase and the procedure in which the solubilized enzyme is assayed. The method for determining the rate of 14CO2 incorporation into low molecular weight, acid soluble substrates by the rat liver microsomal vitamin K-dependent carboxylase has been modified in order to optimize safety, accuracy and simplicity. For these studies the rat liver microsomes containing the vitamin K-dependent carboxylase were isolated by CaCl2 precipitation. These Triton X-100 solubilized microsomes were found to be equivalent to the microsomes obtained by high speed ultracentrifugation with regard to protein concentration, pentapeptide carboxylase activity, carboxylase activity, preprothrombin concentration and total carboxylatable endogenous protein substrate. This modified assay procedure requires fewer steps and pipetting transfers and is quantitatively equivalent to previously employed protocols. The described technique can be adapted for any assay where 14CO2 or H14CO3- is incorporated into non-volatile products. This newly developed assay procedure was employed to assess conditions necessary for optimal vitamin K-dependent carboxylation of the less expensive substrate, N-t-Boc-L-glutamic acid alpha-benzyl ester. The optimal conditions for the carboxylation of N-t-Boc-L-glutamic acid alpha-benzyl ester by the carboxylase were found to be 10 mM N-t-Boc-L-glutamic acid alpha-benzyl ester, 10 mM MgCl2 at 15-18 degrees C. The rate of N-t-Boc-L-glutamic acid alpha-benzyl ester carboxylation under these optimized conditions was found to be higher (1.5-fold) than the rate of carboxylation of 1 mM Phe-Leu-Glu-Glu-Ile in the presence of the cation activator, MgCl2.