High-sensitivity cardiac troponin T: risk stratification tool in patients with symptoms of chest discomfort

Background

Recent studies have demonstrated the association between increased concentrations of high-sensitivity cardiac troponin T (hs-cTnT) and the incidence of myocardial infarction, heart failure, and mortality. However, most prognostic studies to date focus on the value of hs-cTnT in the elderly or general population. The value of hs-cTnT in symptomatic patients visiting the outpatient department remains unclear. The aim of this study was to investigate the prognostic value of hs-cTnT as a biomarker in patients with symptoms of chest discomfort suspected for coronary artery disease and to assess its additional value in combination with other risk stratification tools in predicting cardiac events.

Methods

We studied 1,088 patients (follow-up 2.2±0.8 years) with chest discomfort who underwent coronary calcium scoring and coronary CT-angiography. Traditional cardiovascular risk factors and concentrations of hs-cTnT, N-terminal pro-brain-type natriuretic peptide (NT-proBNP) and high-sensitivity C-reactive protein (hsCRP) were assessed. Study endpoint was the occurrence of late coronary revascularization (>90 days), acute coronary syndrome, and cardiac mortality.

Results

Hs-cTnT was a significant predictor for the composite endpoint (highest quartile [Q4]>6.7 ng/L, HR 3.55; 95%CI 1.88–6.70; P<0.001). Survival analysis showed that hs-cTnT had significant predictive value on top of current risk stratification tools (Chi-square change P<0.01). In patients with hs-cTnT in Q4 versus P<0.01). This was not the case for hsCRP and NT-proBNP.

Conclusions

Hs-cTnT is a useful prognostic biomarker in patients with chest discomfort suspected for coronary artery disease. In addition, hs-cTnT was an independent predictor for cardiac events when corrected for cardiovascular risk profiling, calcium score and CT-angiography results.     

The Discovery of a Reciprocal Relationship between Tyrosine-Kinase Signaling and Cullin Neddylation

While neddylation is known to activate cullin (CUL)-RING ubiquitin ligases (CRLs), its role in regulating T cell signaling is poorly understood. Using the investigational NEDD8 activating enzyme (NAE) inhibitor, MLN4924, we found that neddylation negatively regulates T cell receptor (TCR) signaling, as its inhibition increases IL-2 production, T cell proliferation and Treg development in vitro. We also discovered that loss of CUL neddylation occurs upon TCR signaling, and CRLs negatively regulate IL-2 production. Additionally, we found that tyrosine kinase signaling leads to CUL deneddylation in multiple cell types. These studies indicate that CUL neddylation is a global regulatory mechanism for tyrosine kinase signaling.     

Cytoplasmic expression systems triggered by mRNA yield increased gene expression in post-mitotic neurons

Non-viral vectors are promising vehicles for gene therapy but delivery of plasmid DNA to post-mitotic cells is challenging as nuclear entry is particularly inefficient. We have developed and evaluated a hybrid mRNA/DNA system designed to bypass the nuclear barrier to transfection and facilitate cytoplasmic gene expression. This system, based on co-delivery of mRNA(A64) encoding for T7 RNA polymerase (T7 RNAP) with a T7-driven plasmid, produced between 10- and 2200-fold higher gene expression in primary dorsal root ganglion neuronal (DRGN) cultures isolated from Sprague–Dawley rats compared to a cytomegalovirus (CMV)-driven plasmid, and 30-fold greater expression than the enhanced T7-based autogene plasmid pR011. Cell-free assays and in vitro transfections highlighted the versatility of this system with small quantities of T7 RNAP mRNA required to mediate expression at levels that were significantly greater than with the T7-driven plasmid alone or supplemented with T7 RNAP protein. We have also characterized a number of parameters, such as mRNA structure, intracellular stability and persistence of each nucleic acid component that represent important factors in determining the transfection efficiency of this hybrid expression system. The results from this study demonstrate that co-delivery of mRNA is a promising strategy to yield increased expression with plasmid DNA, and represents an important step towards improving the capability of non-viral vectors to mediate efficient gene transfer in cell types, such as in DRGN, where the nuclear membrane is a significant barrier to transfection.     

Cell Survival and Polarity of Drosophila Follicle Cells Require the Activity of Ecdysone Receptor B1 Isoform

Proper assembly and maintenance of epithelia are critical for normal development and homeostasis. Here, using the Drosophila ovary as a model, we identify a role for the B1 isoform of the ecdysone receptor (EcR-B1) in this process. We performed a reverse genetic analysis of EcR-B1 function during oogenesis and demonstrate that silencing of this receptor isoform causes loss of integrity and multilayering of the follicular epithelium. We show that multilayered follicle cells lack proper cell polarity with altered distribution of apical and basolateral cell polarity markers including atypical-protein kinase C (aPKC), Discs-large (Dlg), and Scribble (Scrib) and aberrant accumulation of adherens junctions and F-actin cytoskeleton. We find that the EcR-B1 isoform is required for proper follicle cell polarity both during early stages of oogenesis, when follicle cells undergo the mitotic cell cycle, and at midoogenesis when these cells stop dividing and undergo several endocycles. In addition, we show that the EcR-B1 isoform is required during early oogenesis for follicle cell survival and that disruption of its function causes apoptotic cell death induced by caspase.     

A multigene phylogenetic study of clonal diversity and divergence in North American strains of the plant pathogen Xylella fastidiosa

Xylella fastidiosa is a pathogen that causes leaf scorch and related diseases in over 100 plant species, including Pierce's disease in grapevines (PD), phony peach disease (PP), plum leaf scald (PLS), and leaf scorch in almond (ALS), oak (OAK), and oleander (OLS). We used a high-resolution DNA sequence approach to investigate the evolutionary relationships, geographic variation, and divergence times among the X. fastidiosa isolates causing these diseases in North America. Using a large data set of 10 coding loci and 26 isolates, the phylogeny of X. fastidiosa defined three major clades. Two of these clades correspond to the recently identified X. fastidiosa subspecies piercei (PD and some ALS isolates) and X. fastidiosa subsp. multiplex (OAK, PP, PLS, and some ALS isolates). The third clade grouped all of the OLS isolates into a genetically distinct group, named X. fastidiosa subsp. sandyi. These well-differentiated clades indicate that, historically, X. fastidiosa has been a clonal organism. Based on their synonymous-site divergence ( approximately 3%), these three clades probably originated more than 15,000 years ago, long before the introduction of the nonnative plants that characterize most infections. The sister clades of X. fastidiosa subsp. sandyi and X. fastidiosa subsp. piercei have synonymous-site evolutionary rates 2.9 times faster than X. fastidiosa subsp. multiplex, possibly due to generation time differences. Within X. fastidiosa subsp. multiplex, a low level ( approximately 0.1%) of genetic differentiation indicates the recent divergence of ALS isolates from the PP, PLS, and OAK isolates due to host plant adaptation and/or allopatry. The low level of variation within the X. fastidiosa subsp. piercei and X. fastidiosa subsp. sandyi clades, despite their antiquity, suggests strong selection, possibly driven by host plant adaptation.     

Recombination and insertion events involving the botulinum neurotoxin complex genes in Clostridium botulinum types A, B, E and F and Clostridium butyricum type E strains

Background  

Clostridium botulinum is a taxonomic designation for at least four diverse species that are defined by the expression of one (monovalent) or two (bivalent) of seven different C. botulinum neurotoxins (BoNTs, A-G). The four species have been classified as C. botulinum Groups I-IV. The presence of bont genes in strains representing the different Groups is probably the result of horizontal transfer of the toxin operons between the species.     

Accreditation and the use of validated/recognised methods to analyse human semen

Accreditation of laboratories who perform diagnostic semen analysis in Australia and New Zealand is a requirement of the healthcare system. Within the accreditation process laboratories are required to set ISO standards within their policies and procedures. In order to achieve their aims, laboratories need to be able to measure a number of defined semen parameters both accurately and repetitively, especially around the lower limit of the reference intervals. The methods documented in the WHO-manual are used almost universal as the laboratory standard. Some laboratories incorporate minor method variations into their procedures. As part of the ISO requirements all variations require validation using internally approved processes that are documented and that incorporate appropriate statistical analysis and comparison of results. Validation is an ongoing process and regular review is essential. Evidence of the validation must be available for review by external auditors during accreditation. Where any validated variant method returns results that are significantly different to any method within the WHO-manual, the laboratory needs to develop its own, in-house reference interval for that method.     

The burden of common infectious disease syndromes at the clinic and household level from population-based surveillance in rural and urban Kenya

Background

Characterizing infectious disease burden in Africa is important for prioritizing and targeting limited resources for curative and preventive services and monitoring the impact of interventions.

Methods

From June 1, 2006 to May 31, 2008, we estimated rates of acute lower respiratory tract illness (ALRI), diarrhea and acute febrile illness (AFI) among >50,000 persons participating in population-based surveillance in impoverished, rural western Kenya (Asembo) and an informal settlement in Nairobi, Kenya (Kibera). Field workers visited households every two weeks, collecting recent illness information and performing limited exams. Participants could access free high-quality care in a designated referral clinic in each site. Incidence and longitudinal prevalence were calculated and compared using Poisson regression.

Results

Incidence rates resulting in clinic visitation were the following: ALRI — 0.36 and 0.51 episodes per year for children <5 years and 0.067 and 0.026 for persons ≥5 years in Asembo and Kibera, respectively; diarrhea — 0.40 and 0.71 episodes per year for children <5 years and 0.09 and 0.062 for persons ≥5 years in Asembo and Kibera, respectively; AFI — 0.17 and 0.09 episodes per year for children <5 years and 0.03 and 0.015 for persons ≥5 years in Asembo and Kibera, respectively. Annually, based on household visits, children <5 years in Asembo and Kibera had 60 and 27 cough days, 10 and 8 diarrhea days, and 37 and 11 fever days, respectively. Household-based rates were higher than clinic rates for diarrhea and AFI, this difference being several-fold greater in the rural than urban site.

Conclusions

Individuals in poor Kenyan communities still suffer from a high burden of infectious diseases, which likely hampers their development. Urban slum and rural disease incidence and clinic utilization are sufficiently disparate in Africa to warrant data from both settings for estimating burden and focusing interventions.