Is downstream cardiac testing required in patients with reduced functional capacity and otherwise negative exercise stress test? A single center observational study

Background: Exercise stress testing (EST) in patients with poor functional capacity measured by timeon treadmill is typically deemed inconclusive and usually leads to further downstream testing. The aimof this study was firstly to evaluate the maximum rate pressure product (MRPP) during initial EST toassessthe need for follow-up testing; and secondly to investigate if MRPP is better than age predictedmaximum heart rate (APMHR) for diagnostic outcome based on follow up cardiovascular (CV) eventsin patients with inconclusive EST due to poor functional capacity.Methods: From a total of 2761 tests performed, 236 tests were considered inconclusive due to poorfunctional capacity which were available for analysis. From receiver operating characteristic (ROC)analysis, a cut-off value for MRPP of 25000 was chosen using CV events as the outcome measure(sensitivity 97%, specificity 45%). Cases were then categorised into those with an MRPP > 25000 and< 25000.Results: Regardless of treadmill time, any patient attaining an MRPP > 25000 had no abnormaldownstream testing or CV events at 2 years follow-up. On ROC analysis MRPP outperformed APMHRfor sensitivity and specificity (area under curve 0.76 vs. 0.59, respectively).Conclusions: The results suggest that regardless of functional capacity, individuals whose EST is terminatedat maximal fatigue, with no electrocardiogram evidence or symptoms of myocardial ischemiaand yields an MRPP > 25000, do not require further downstream testing. Furthermore, this groupof patients, while not immune to future CV events, have significantly better outcomes than those notattaining a MRPP > 25000

Comparison of Heart Rate Blood Pressure Product Versus Age-Predicted Maximum Heart Rate as Predictors of Cardiovascular Events During Exercise Stress Echocardiography

Exercise stress echocardiograms (ESEs) are a functional cardiovascular (CV) test typically used for the investigation of coronary artery disease. ESEs are often terminated at a predetermined age-predicted maximum heart rate (APMHR) to facilitate timely acquisition of ultrasound images at peak exercise. Although an APMHR of 85% is often used, this has not been validated as a suitable termination end point. Heart rate blood pressure product (HRBPP) as an established measure of myocardial work may provide a more reliable assessment of cardiac workload. The aim of this study was to assess maximal HRBPP (MHRBPP) and APMHR as markers of cardiac workload during ESE, using CV events at mean follow-up as the outcome variable. After exclusions, 712 patients being investigated for ischemic heart disease, performed an ESE to volitional fatigue using the standard Bruce protocol. Patient demographics and test data were collected and patients followed for 4.4 ± 2.1 years. Cut-points for MHRBPP (25,060; area under curve 0.77) and APMHR (93.8% and 97.9%; area under curve 0.71; p = 0.12 for difference) were established from receiver operating characteristic analysis. Those achieving an APMHR >85% but MHRBPP 25,060 regardless of APMHR (

Prediction of hospital outcome in septic shock: a prospective comparison of tissue Doppler and cardiac biomarkers

Introduction: Diastolic dysfunction as demonstrated by tissue Doppler imaging (TDI), particularly E/e' (peak early diastolic transmitral/peak early diastolic mitral annular velocity) is common in critical illness. In septic shock, the prognostic value of TDI is undefined. This study sought to evaluate and compare the prognostic significance of TDI and cardiac biomarkers (B-type natriuretic peptide (BNP); N-terminal proBNP (NTproBNP); troponin T (TnT)) in septic shock. The contribution of fluid management and diastolic dysfunction to elevation of BNP was also evaluated

LHS6343C: A Transiting Field Brown Dwarf Discovered by the Kepler Mission

We report the discovery of a brown dwarf that transits one member of the M+M binary system LHS6343AB every 12.71 days. The transits were discovered using photometric data from the Kelper public data release. The LHS6343 stellar system was previously identified as a single high-proper-motion M dwarf. We use high-contrast imaging to resolve the system into two low-mass stars with masses 0.45 Msun and 0.36 Msun, respectively, and a projected separation of 55 arcsec. High-resolution spectroscopy shows that the more massive component undergoes Doppler variations consistent with Keplerian motion, with a period equal to the transit period and an amplitude consistent with a companion mass of M_C = 62.8 +/- 2.3 Mjup. Based on an analysis of the Kepler light curve we estimate the radius of the companion to be R_C = 0.832 +/- 0.021 Rjup, which is consistent with theoretical predictions of the radius of a > 1 Gyr brown dwarf.Comment: Our previous analysis neglected the dependence of the scaled semimajor axis, a/R, on the transit depth. By not correcting a/R for the third-light contamination, we overestimated the mass of Star A, which led to an overestimate the mass and radius of the LHS6343

Baseline and follow-up assessment of regional left ventricular volume using 3-dimensional echocardiography: comparison with cardiac magnetic resonance

The assessment of regional volumes is an option for analysis of the response of LV segments to interventions such as revascularization or cell therapy. We sought to compare regional volumes from 3D-echocardiography (3DE) with cardiac magnetic resonance (CMR) over follow-up

Modified "Allele-Specific qPCR" Method for SNP Genotyping Based on FRET

Peer reviewe

An accurate, reliable, and universal qPCR method to identify homozygous single insert T-DNA with the example of transgenic rice

Early determination of transgenic plants that are homozygous for a single locus T-DNA insert is highly desirable in most fundamental and applied transgenic research. This study aimed to build on an accurate, rapid, and reliable quantitative real-time PCR (qPCR) method to fast-track the development of multiple homozygous transgenic rice lines in the T1 generation, with low copy number to single T-DNA insert for further analyses. Here, a well-established qPCR protocol, based on the OsSBE4 reference gene and the nos terminator, was optimized in the transgenic Japonica rice cultivar Nipponbare, to distinguish homozygous single-insert plants with 100% accuracy. This method was successfully adapted to transgenic Indica rice plants carrying three different T-DNAs, without any modifications to quickly develop homozygous rice plants in the T1 generation. The accuracy of this qPCR method when applied to transgenic Indica rice approached 100% in 12 putative transgenic lines. Moreover, this protocol also successfully detected homozygous single-locus T-DNA transgenic rice plants with two-transgene T-DNAs, a feature likely to become more popular in future transgenic research. The assay was developed utilizing universal primers targeting common sequence elements of gene cassettes (the nos terminator). This assay could therefore be applied to other transgenic plants carrying the nos terminator. All procedures described here use standardized qPCR reaction conditions and relatively inexpensive dyes, such as SYBR Green, thus the qPCR method could be cost-effective and suitable for lower budget laboratories that are involved in rice transgenic research

The potential for production of high quality bio-coal from early harvested Miscanthus by hydrothermal carbonisation

To meet combustion quality requirements, Miscanthus is conventionally harvested in late winter/early spring after senescence due to a lowering of fuel nitrogen, chlorine and ash content. This can overcome combustion issues such as slagging, fouling and corrosion however there is a significant reduction in dry matter yields compared to early harvesting in the autumn. In this study, Miscanthus × giganteus harvested conventionally (after senescence) and early (green) have been pre-treated by hydrothermal carbonisation (HTC) at 200 °C and 250 °C. HTC at 200 °C improves the grindability of the biomass but results in limited energy densification. HTC at 250 °C results in increased energy densification producing a bio-coal with a HHV ranging from 27 to 28 MJ/kg for early and 25 to 26 MJ/kg for conventional harvesting; the Hardgrove Grindability Index (HGI) increases from 0 to 150. At higher HTC temperatures, the combustion profile of the bio-coal exhibits a ‘coal like’ single stage combustion profile. HTC results in a significant reduction in alkali metal content, increases safe combustion temperatures and reduces the theoretical propensity of the derived fuel to slag, foul and corrode. The results indicate that HTC can valorise both conventional and early harvested Miscanthus without producing any adverse effect on the yields and quality of the bio-coal. The challenges associated with early harvesting of Miscanthus appear to be largely overcome by HTC resulting in increased yields of up to 40% per hectare due to reduction in dry matter loss

The General Transcription Repressor TaDr1 Is Co-expressed With TaVrn1 and TaFT1 in Bread Wheat Under Drought

The general transcription repressor, TaDr1 gene, was identified during screening of a wheat SNP database using the Amplifluor-like SNP marker KATU-W62. Together with two genes described earlier, TaDr1A and TaDr1B, they represent a set of three homeologous genes in the wheat genome. Under drought, the total expression profiles of all three genes varied between different bread wheat cultivars. Plants of four high-yielding cultivars exposed to drought showed a 2.0–2.4-fold increase in TaDr1 expression compared to controls. Less strong, but significant 1.3–1.8-fold up-regulation of the TaDr1 transcript levels was observed in four low-yielding cultivars. TaVrn1 and TaFT1, which controls the transition to flowering, revealed similar profiles of expression as TaDr1. Expression levels of all three genes were in good correlation with grain yields of evaluated cultivars growing in the field under water-limited conditions. The results could indicate the involvement of all three genes in the same regulatory pathway, where the general transcription repressor TaDr1 may control expression of TaVrn1 and TaFT1 and, consequently, flowering time. The strength of these genes expression can lead to phenological changes that affect plant productivity and hence explain differences in the adaptation of the examined wheat cultivars to the dry environment of Northern and Central Kazakhstan. The Amplifluor-like SNP marker KATU-W62 used in this work can be applied to the identification of wheat cultivars differing in alleles at the TaDr1 locus and in screening hybrids

Status and prospects for renewable energy using wood pellets from the southeastern United States

The ongoing debate about costs and benefits of wood-pellet based bioenergy production in the southeastern United States (SE USA) requires an understanding of the science and context influencing market decisions associated with its sustainability. Production of pellets has garnered much attention as US exports have grown from negligible amounts in the early 2000s to 4.6 million metric tonnes in 2015. Currently, 98% of these pellet exports are shipped to Europe to displace coal in power plants. We ask, ‘How is the production of wood pellets in the SE USA affecting forest systems and the ecosystem services they provide?’ To address this question, we review current forest conditions and the status of the wood products industry, how pellet production affects ecosystem services and biodiversity, and what methods are in place to monitor changes and protect vulnerable systems. Scientific studies provide evidence that wood pellets in the SE USA are a fraction of total forestry operations and can be produced while maintaining or improving forest ecosystem services. Ecosystem services are protected by the requirement to utilize loggers trained to apply scientifically based best management practices in planning and implementing harvest for the export market. Bioenergy markets supplement incomes to private rural landholders and provide an incentive for forest management practices that simultaneously benefit water quality and wildlife and reduce risk of fire and insect outbreaks. Bioenergy also increases the value of forest land to landowners, thereby decreasing likelihood of conversion to nonforest uses. Monitoring and evaluation are essential to verify that regulations and good practices are achieving goals and to enable timely responses if problems arise. Conducting rigorous research to understand how conditions change in response to management choices requires baseline data, monitoring, and appropriate reference scenarios. Long-term monitoring data on forest conditions should be publicly accessible and utilized to inform adaptive management