Metal sulfides have attracted considerable scrutiny compared to metal oxides owing to their distinguished electrochemical properties and various applications, such as solar cells and supercapacitors.

Mesenchymal stem cells (MSCs) are multipotent, can be easily expanded in culture and hence are an attractive therapeutic tool for cardiac repair. MSCs have tremendous potential to transdifferentiate to cardiac lineage both in vitro and in vivo. The present study examined the differentiation capacity of conditioned media derived from ischemic cardiac tissue on human MSCs. Human Bone marrow-derived MSCs after due characterization by immunocytochemistry and flow cytometry for MSC specific markers were induced by culture media derived from ischemic (n = 13) and non-ischemic (n = 18) human cardiac tissue. Parallel cultures were treated with 5-azacytidine (5-azaC), a potent cardiomyogen. MSCs induced with ischemic conditioned media formed myotube like structures, expressed sarcomeric Troponin I, alpha myosin heavy chain proteins and were positive for cardiac specific markers (Nkx2.5, human atrial natriuretic peptide, myosin light chain-2a, GATA-4) as was observed in 5-azaC treated cells. However, uninduced MSCs as well as those induced with non-ischemic cardiac conditioned media still maintained the fibroblast morphology even after 3 weeks post-induction. Transmission electron microscopic studies of cardiomyocyte-like cells derived from MSCs revealed presence of sarcomeric bands but failed to show gap junctions and intercalated discs as of adult cardiomyocytes. These findings demonstrate that ischemic cardiac conditioned media induces morphological and molecular changes in MSCs with cardiac features, but at a primitive stage. Proteomics analysis of the ischemic conditioned media revealed differential expression of three relevant proteins (C-type lectin superfamily member 13, Testis-specific chromodomain protein Y2 and ADP/ATP translocase 1), whose exact role in cardiac regeneration needs further analysis.

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IntroductionThe use of a vascular-valved conduit in the right side of the heart is common in pediatric cardiac surgery. For instance, Tetrology of Fallot with pulmonary atresia often requires a procedure called Rastelli repair, where valved conduits are used. The gold standard is to use a homograft aorta or pulmonary artery but due to lack of availability of homografts here, more so the smaller sizes, other options were explored. Synthetic grafts are resorted to despite the drawback of the use of life long Abstract Background: Xenogenic organ replacement from pig to human is a possibility provided sterility and immunogenicity are taken care of. The objective of this study was to check the sterility of processed porcine pulmonary xenografts to mark them 'safe' for clinical application, without the threat for xenozoonoses.Methods: A total of 148 porcine pulmonary valve conduits were screened pre and post processing for bacterial, fungal and viral contamination. The bacterial and fungal contaminants such as Candida species, filamentous fungus, yeast like organisms, gram negative bacteria and porcine endogenous retrovirus (PERV) were isolated from the preprocessed porcine conduits. These harvested conduits were collected in a cocktail of antimicrobials and Hanks balanced salt solution. Next, they were subjected to 'processing' i.e., made completely acellular, strong and biocompatible in all respects. Finally, sterility checks were carried out for bacterial, fungal and viral (PERV) contamination.Result: Microbial evaluation performed in this study revealed that the porcine pulmonary conduits were made 'microbe free' on subjecting to the special staged decellularization technique.Conclusion: The porcine xenograft conduit processed in the laboratory, which has an added advantage of numbers and sizes, can replace the gold standard homograft safely. (Ind J Thorac Cardiovasc Surg, 2007; 23: 240-245)

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