Increased inducible nitric oxide synthase (iNOS) expression in human myocardial infarction.

Increased inducible nitric oxide synthase (iNOS) expression has been reported in heart failure, cardiomyopathies, and arteriosclerosis. iNOS is expressed in the heart upon inflammatory stimuli and produces excessive amounts of nitric oxide (NO). The overproduction of NO is cytotoxic and involved in cardiovascular diseases. Furthermore, iNOS produces superoxide anion which proceeds with NO to the harmful oxidant peroxynitrite, causing oxidative stress in the heart. The aim of the study was to gain new insights into the role of iNOS in human myocardial infarction (MI) and its contribution to oxidative stress in the heart. Furthermore, we investigated the unaffected myocardium of the infarction hearts, to study if iNOS expression is increased, probably as an indicator for oxidative stress. Our results show a significant increase (p = 0.013) of the iNOS expression in the affected regions of MI hearts (n = 9) in comparison with healthy control hearts (n = 4). In the unaffected regions of MI hearts, an increase in the iNOS expression in some samples was found as well. Our study demonstrated the direct detection of iNOS mRNA in human myocardial tissue. The balance between beneficial and deleterious effects of iNOS may be particularly influenced by the presence or absence of concurrent oxidative stress.

Sudden unexpected death in the young - Value of massive parallel sequencing in postmortem genetic analyses.

Cases of sudden cardiac death (SCD) in young and apparently healthy individuals represent a devastating event in affected families. Hereditary arrhythmia syndromes, which include primary electrical heart disorders as well as cardiomyopathies, are known to contribute to a significant number of these sudden death cases. We performed postmortem genetic analyses in young sudden death cases (aged <45years) by means of a defined gene panel using massive parallel sequencing (MPS). The data were evaluated bioinformatically and detected sequence variants were assessed using common databases and applying in silico prediction tools. In this study, we identified variants with likely pathogenic effect in 6 of 9 sudden unexpected death (SUD) cases. Due to the detection of numerous unknown and unclassified variants, interpretation of the results proved to be challenging. However, by means of an appropriate evaluation of the findings, MPS represents an important tool to support the forensic investigation and implies great progress for relatives of young SCD victims facilitating adequate risk stratification and genetic counseling.

Kit-dependent discrepancy in D16S539 and general considerations for database matches.

Throughout the last decade more companies have been offering multiplex PCR kits for forensic STR typing. As a consequence, it has been demonstrated, that an observed genotype may unexpectedly vary at a single locus when different STR kits have been used. Analysing STR profiles which have to be entered in a national database, unknown or undetected primer binding site mutations, insertions or deletions within the flanking region of STR loci may hinder matches and therefore have far-reaching consequences. The current study is a further example indicating that sequence variations in flanking regions are a common problem within STR typing which should not be underestimated. A deletion of 16 nucleotides close to the primer binding site downstream of the repeat sequence resulted in deviant genotypes at the D16S539 locus according to different STR kits used.

Characterization of a novel KCNJ2 sequence variant detected in Andersen-Tawil syndrome patients.

BACKGROUND: Mutations in the KCNJ2 gene encoding the ion channel Kir2.1 have been linked to the Andersen-Tawil syndrome (ATS). Molecular genetic screening performed in a family exhibiting clinical ATS phenotypes unmasked a novel sequence variant (c.434A > G, p.Y145C) in this gene. The aim of this study was to investigate the effect of this variant on Kir2.1 ion channel functionality. METHODS: Mutant as well as wild type GFP tagged Kir2.1 channels were expressed in HEK293 cells. In order to examine the effect of the new variant, electrophysiological measurements were performed using patch clamp technique. Cellular localization of the mutant in comparison to the wild type ion channel was analyzed by confocal laser scanning microscopy. RESULTS: The currents of cells expressing only mutant channels or a mixture of wild type and mutant were significantly reduced compared to those expressing wild type (WT) channels (p < 0.01). Whereas WT expressing cells exhibited at -120 mV an averaged current of -4.5 ± 1.9 nA, the mutant generates only a current of -0.17 ± 0.07 nA. A co-expression of mutant and WT channel generates only a partial rescue of the WT current. Confocal laser scanning microscopy indicated that the novel variant is not interfering with synthesis and/or protein trafficking. CONCLUSIONS: The detected sequence variant causes loss-of-function of the Kir2.1 channel and explains the clinical phenotypes observed in Andersen-Tawil syndrome patients.

Relevance of molecular testing in patients with a family history of sudden death.

Sudden cardiac death (SCD) is a major cause of death in industrial countries. Although SCD occurs mainly in adults, it may also affect young persons, where genetic cardiac disorders comprise at least half of these cases. This includes primary arrhythmogenic disorders such as long QT syndrome and inherited cardiomyopathies. However, in many cases, postmortem examinations provide no conclusive results explaining the cause of death. Since family members of the deceased may eventually have inherited the same disease, they are at risk of SCD. In the present study, 28 patients with a family history of sudden unexplained death (SUD), of survived cardiac arrest and with a clinical diagnosis of an inherited cardiac disease were screened using phenotype-guided molecular analysis of genes associated with arrhythmogenic cardiac diseases. In 64% of the cases, gene variants with potentially pathogenic cardiac effects were detected suggesting that an arrhythmia syndrome may have caused the death of the deceased family member. Therefore, we recommend that relatives of SUD victims should undergo extended cardiac examination and, depending on the clinical diagnosis, a targeted genetic analysis should follow, which is crucial to identify family members at risk.

Characterization of 15 STR cannabis loci: nomenclature proposal and SNPSTR haplotypes.

The standardization of methods for individualizing Cannabis sativa plants could offer new possibilities in the investigation of its illegal trade. Here we present the first nomenclature proposal for 15 cannabis STRs, which allows an initial standardization for performing comparisons between laboratories and generating genotype databases. Several alleles of the 15 STR loci have been sequenced. This has revealed that not all the STR loci are equally suitable for the individualization purposes. Moreover, several nucleotide variations have been detected both inside the repeat structure and/or in the flanking region. All the different SNPSTR haplotypes are presented and compared with the previous sequence raw data of the 15 STR loci. The SNPSTR data could considerably increase the informative value of the STRs, which could be very useful in complex cases.