Myocardial fibrosis predicts ventricular arrhythmias and sudden death after cardiac electronic device implantation

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Unrestricted educational grants

Background

Increasing evidence supports a link between myocardial fibrosis (MF) and ventricular arrhythmias. We sought to determine whether presence of MF on visual assessment (MFVA) and gray zone fibrosis (GZF) mass predicts SCD and ventricular fibrillation / sustained ventricular tachycardia after cardiac implantable electronic device (CIED) implantation.

Methods

In this prospective study, total fibrosis and GZF mass, quantified using cardiovascular magnetic resonance, was assessed in relation to the primary endpoint of sudden cardiac death (SCD) and the secondary, arrhythmic endpoint of SCD or ventricular arrhythmias after CIED implantation.

Results

Among 700 patients (age 68.0 ± 12.0yrs [mean ± SD]), 27 (3.85%) experienced a SCD and 121 (17.3%) met the arrhythmic endpoint over 6.93 yrs (median; interquartile range 5.82-9.32). MFVA predicted SCD (hazard ratio [HR]: HR:26.3 [95% confidence interval [CI] 3.70-3337]; negative predictive value: 100%). In competing risks analyses, MFVA also predicted the arrhythmic endpoint (subdistribution [sHR]: 19.9 [95% CI 6.40-61.9]; negative predictive value:98.6%). Compared with no MFVA, a GZF mass measured with the 5SD method (GZF5SD) > 17 g was associated with highest risk of SCD (HR: 44.6;95% CI 6.12-5685) and the arrhythmic endpoint (sHR: 30.3 [95% CI 9.60-95.8]). Adding GZF5SD mass to MFVA led to reclassification of 39% for SCD and 50.2% for the arrhythmic endpoint. In contrast, LVEF did not predict either endpoint.

Conclusions

In CIED recipients, MFVA excluded patients at risk of SCD and virtually excluded ventricular arrhythmias. Quantified GZF5SD mass added predictive value in relation to SCD and the arrhythmic endpoint.

Analysis of existence of multidrug-resistant H58 gene in Salmonella enterica serovar Typhi isolated from typhoid fever patients in Makassar, Indonesia

The surveillance of multidrug-resistant (MDR) H58 typhoid is highly important, especially in endemic areas. MDR strain detection is needed by using a simple PCR technique that only uses a pair of primers. This is conducted considering the detection of Salmonella Typhi strains that have been carried out so far are only using antimicrobial sensitivity tests to determine microbial resistance phenotypically and to determine genotypically using complex molecular techniques. We aimed to analyse the existence of Salmonella Typhi MDR H58 in patients with typhoid fever in Makassar, Indonesia. A total of 367 blood samples of typhoid fever patients were collected from April 2018 until April 2019. The blood sample was cultured, then confirmed via simple PCR. All of the confirmed samples were tested for susceptibility against antibiotics and molecularly analysed for MDR H58 existence using a simple PCR technique. We found 7% (27/367) of the samples to be positive by both blood culture and PCR. All 27 isolates were found to be sensitive to sulfamethoxazole/trimethoprim. The lowest drug sensitivities were to amoxicillin, at one (3.7%) of 27 isolates, and ampicillin, at 13 (48.1%) of 27 isolates. Salmonella Typhi H58 PCR results showed that one (3.7%) of 27 isolates carried a positive fragment of 993 bp that led to the H58 strain, since the deletion flanks this fragment. The isolate was also found to be resistant to amoxicillin and fluoroquinolone according to a sensitivity test. Further molecular analysis needs to be conducted to examine the single isolate that carried the 933 bp fragment.

The effect of anti-tuberculosis drugs therapy on mRNA efflux pump gene expression of Rv1250 in Mycobacterium tuberculosis collected from tuberculosis patients

Efflux pumps are transmembrane proteins that vigorously participate in extruding a wide range of substrates, including drugs, outside the bacterial cell. We aimed to investigate the mRNA expression level of the Rv1250 efflux pump gene in Mycobacterium tuberculosis isolated from individuals with tuberculosis who received drug therapy, at the 1st, 3rd and 5th months, and newly diagnosed patients with tuberculosis who will receive drug therapy (0 month). The study was a multiple cross-sectional longitudinal design—50 different M. tuberculosis isolates and a reference strain H37Rv were subcultured in LJ medium and confirmed by multiplex PCR for identification of M. tuberculosis and collected for RNA extraction. Total bacterial mRNA was analysed using real-time quantitative PCR to evaluate mRNA quantification gene expression. There were differences in the level of Rv1250 mRNA expression between sensitive (n = 11) and resistant (n = 40) groups of 5.961 ± 0.414 and 10.192 ± 1.978, respectively (fold changes; p < 0.05). There were significant differences of expression level among M. tuberculosis-resistant groups (p < 0.05) specifically 7.573 ± 0.424 for 0-month drug therapy (n = 10), 9.438 ± 0.644 for 1st month drug therapy (n = 10), 11.057 ± 0.262 for 3rd month drug therapy (n = 10) and 12.701 ± 0.460 for 5th month drug therapy (n = 10). We assume that the extent of Rv1250 gene expression in M. tuberculosis clinical isolates is a result of the exposure to antimicrobials during treatment, which affect the basic expression of the efflux pump Rv1250 gene.

Bacterial lipopolysaccharide-mediated murine fetal death: the role of interleukin-1

OBJECTIVE

Our purpose was to determine whether interleukin-1 is an important mediator of lipopolysaccharide-induced fetal death and, if so, whether interleukin-1 causes fetal death by inducing prostanoid formation in gestational tissues.

STUDY DESIGN

Pregnant C3H/HeN mice were administered lipopolysaccharide, interleukin-1alpha, interleukin-beta, or vehicle on days 11 to 13 of pregnancy. Mice were killed 72 hours later and the fetal status was determined. Some mice were pretreated with anti-interleukin-1-receptor antibodies or indomethacin. Decidual explants were established from treated mice, and supernatants were assayed for interleukin-1beta and prostaglandin E2.

RESULTS

Decidua taken from lipopolysaccharide-treated mice produced significantly increased amounts of interleukin-1beta, and pretreatment with anti-interleukin-1-receptor antibodies reduced the proportion of fetal deaths after lipopolysaccharide administration from 100% to 33%. The administration of interleukin-1alpha caused fetal death in a dose-dependent fashion, and decidua taken from interleukin-1-treated mice produced significantly increased amounts of prostaglandin E2. However, pretreatment with doses of indomethacin that abrogated decidual prostaglandin E2 production did not reduce the proportion of fetal death after interleukin-1alpha administration.

CONCLUSIONS

Interleukin-1 is an important mediator of lipopolysaccharide-induced fetal death and causes fetal death by prostaglandin-independent effects.

Pathogenic antibodies in women with obstetric features of antiphospholipid syndrome who have negative test results for lupus anticoagulant and anticardiolipin antibodies

OBJECTIVE

Our goal was to determine whether women with clinical features of antiphospholipid syndrome but negative test results for lupus anticoagulant and anticardiolipin antibodies have pathogenic antibodies not identified by currently used methods.

STUDY DESIGN

Sera were obtained from women with clinical features associated with antiphospholipid antibodies who had negative test results for lupus anticoagulant and anticardiolipin antibodies (antiphospholipid syndrome-like). We studied (1) the effect of passive immunization with their purified immunoglobulin G fraction on murine pregnancy (n = 35) and (2) the presence of antiphospholipid antibodies other than lupus anticoagulant or anticardiolipin antibodies (n = 39). Sera were also retested for anticardiolipin antibodies and lupus anticoagulant.

RESULTS

Fetal loss occurred in 235 of 1088 (22%) pups in 137 mice immunized with immunoglobulin G fraction from antiphospholipid syndrome-like women compared with 23 of 402 (6%) pups in 53 control mice. Immunoglobulin G from 11 study patients resulted in the loss of at least one third of the exposed pups. Five women had positive levels of antiphosphatidylserine antibodies (>99th percentile). All levels were low positive, and three women also had low-positive levels of anticardiolipin antibodies on repeat testing. Five of the 11 (45%) women whose immunoglobulin G fractions caused at least 33% fetal loss also had positive test results for antiphospholipid antibodies.

CONCLUSIONS

A subset of women with clinical disorders suspicious for antiphospholipid syndrome but who had negative test results for lupus anticoagulant and anticardiolipin antibodies by current methods have serum immunoglobulin G that is pathogenic to murine pregnancy. Testing for pathogenic immunoglobulin G may provide additional means to identify women with an as yet uncharacterized immune condition. The clinical relevance of low levels of antiphospholipid antibodies in these women remains unproved.

Schizophrenia and GABAA receptor subunit genes

Alterations in gamma-aminobutyric acid (GABA) neurotransmission have been indirectly implicated in the pathogenesis of schizophrenia. Using nine multiplex pedigrees, we tested for linkage between schizophrenia and simple sequence repeat polymorphisms for the GABAA receptor alpha 1, alpha 2, alpha 4, alpha 5, alpha 6, beta 1 and beta 3 subunit genes. Evidence of linkage was not found when assuming either autosomal dominant or autosomal recessive inheritance. The non-parametric sib pair test also did not reveal significant evidence of deviation from expected segregation ratios.

Search for mutations in the beta 1 GABAA receptor subunit gene in patients with schizophrenia

As alterations in GABAergic neurotransmission have been indirectly implicated in the pathogenetics of schizophrenia, GABAA receptor subunit genes are plausible candidate genes for the illness. We undertook a search for sequence variations in the coding region of beta 1 subunit gene by designing intron-based primers to amplify its 9 exons. Using single strand conformation polymorphism (SSCP) analysis, we found an exon 9 variant present in 3 of 86 unrelated schizophrenic cases derived from families having at least 2 first-degree relatives with schizophrenia. Direct sequencing of the SSCP variant revealed a C-->G nucleotide transversion at codon 396 predicting a histidine to glutamine substitution in the beta 1 peptide. The predicted amino acid substitution occurs at a highly conserved site, 9 residues from a cAMP-dependent serine phosphorylation consensus sequence. All known GABAA beta 1 subunit genes including human, bovine, and rat, code for histidine at position 396. Although the variant cosegregated with disease in a family with 2 affected sibs, it was only transmitted to 2 of 3 affected sibs in a multiplex family. The variant was not found in an additional sample comprising 155 unrelated schizophrenics and the sequence variant was present at a low frequency (approximately 1.1%) in control groups. Although these results indicate that the sequence variant is likely to be a natural polymorphism, it is possible that the variant may be a predisposing allele in rare instances. It is also possible that the variant may change the function or regulation of the GABAA receptor complex and it may be of pharmacogenetic relevance.

Stuttering as a phenotype for behavioral genetics research

Stuttering is a broad behavioral phenotype with an adult prevalence of 0.7-1.0%. Family, twin, and segregation studies all indicate that stuttering has a large genetic component to its etiology. The relatively simple phenotype, the early onset, and the apparent rarity of phenocopies of adult stuttering all make stuttering a promising model for the study of the genetics of broad behavioral phenotypes.