Dynamics of Ventricular Repolarization in Patients with Dilated Cardiomyopathy Versus Healthy Subjects

Background: Patients with impaired left ventricular function have a high risk of developing ventricular arrhythmias and sudden death. Among different markers of risk, the prolongation and regional heterogeneity of repolarization are of increasing interest. However, there are limited data regarding feasibility of analyzing repolarization parameters and their dynamics in 24‐hour Holter ECG recordings. Methods: Dynamic behavior of repolarization parameters was studied with a new automatic algorithm in digital 24‐hour Holter recordings of 60 healthy subjects and 55 patients with idiopathic dilated cardiomyopathy (IDC). Repolarization parameters included the mean value of QT and QTc durations, QT dispersion, and peaks of QT duration and QT dispersion above prespecified thresholds. Results: In comparison to healthy subjects, patients with IDC had lower heart rate variability, longer mean QT and QTc durations, higher content of QTc peaks >500 ms, longer QT dispersion and its standard deviation, and a higher content of peaks >100 ms of QT dispersion (P < 0.01 for all comparisons). These repolarization parameters were significantly higher in IDC patients after adjustment for age, sex, and heart rate variability. The parameters of repolarization dynamics correlated with SDNN in healthy subjects but not in dilated cardiomyopathy patients. Conclusions: The automatic assessment of repolarization parameters in 24‐hour digital ECG recordings is feasible and differentiates dilated cardiomyopathy patients from healthy subjects. Patients with dilated cardiomyopathy have increased QT duration, QT dispersion, and increased variability of QT dispersion reflecting variations in T‐wave morphology, the factors which might predispose them to the development of arrhythmic events.     

Assessment of the Impact of Shot-Peening on the Fatigue Life of a Compressor Blade Subjected to Resonance Vibrations

This publication presents an assessment of the influence of a surface treatment such as shot-peening on the fatigue life of a compressor blade exposed to resonant vibrations. As part of the work, a geometric model of the blade was developed, and a numerical modal and fatigue analysis were performed. The fatigue analysis was based on the Manson–Coffin–Basquin and Ramberg–Osgood models. Additionally, the location of the highest equivalent stresses was established. Based on the results of the strength analysis, two points were identified where a fatigue crack may potentially occur. As part of the work, the influence of different values of residual stresses on the results of the fatigue life was determined. The obtained results were compared to the literature values of fatigue life for this blade. A secondary objective of the study was to determine the size of the grains at various points of the blade, as well as the thickness of the layer plasticized as a result of peening. The relationship between the location of the highest values of the equivalent stresses and the thickness of the plasticized layer was determined. An explanation of the effect of shot-peening on the increase in the fatigue life of the blade was proposed.     

Oral Prolonged‐Release Oxycodone/Naloxone for Managing Pain and Opioid‐Induced Constipation: A Review of the Evidence

Background

Opioids provide effective relief from moderate‐to‐severe pain and should be prescribed as part of a multifaceted approach to pain management when other treatments have failed. Fixed‐dose oxycodone/naloxone prolonged‐release tablets (OXN PR) were designed to address the opioid class effect of opioid‐induced constipation (OIC) by combining the analgesic efficacy of oxycodone with the opioid receptor antagonist, naloxone, which has negligible systemic availability when administered orally. This formulation has abuse‐deterrent properties, since systemic exposure to naloxone by parenteral administration would antagonize the euphoric effects of oxycodone.

Methods

A literature search was conducted to assess the evidence base for OXN PR to treat moderate‐to‐severe pain and its impact on bowel function, based on published clinical trials and observational studies.

Results

Extensive data demonstrate that OXN PR provides effective analgesia and clinically relevant improvements in bowel function in patients with OIC and moderate‐to‐severe cancer‐related pain and noncancer pain types such as low back pain, neuropathic pain, and musculoskeletal pain. OXN PR has also been found to improve bowel function in patients with OIC refractory to multiple types of laxatives, and improve Parkinson's disease–related pain. No unanticipated safety concerns have been reported in elderly patients.

Conclusions

Evidence from clinical trials and observational studies confirms that for selected patients OXN PR significantly improves moderate‐to‐severe chronic pain and provides relief from OIC. Treatment should be tailored to individual patients to establish the lowest effective dose. An absence of analgesic ceiling effect was seen across the clinically relevant dose range investigated (≤ 160/80 mg/day).     

Synthesis,Characterization and Field‐Effect Transistor Performance of Poly[2,6‐bis(3‐alkylthiophen‐2‐yl)benzo[1,2‐b;4,5‐b′]diselenophene]s

Benzo[1,2‐b:4,5‐b′]diselenophene (BDS) has been incorporated for the first time in a polymer. bis(Stannyl)‐functionalized BDS was copolymerized with 3,3′‐bis(alkyl)‐5,5′‐bithiophenes (dodecyl and tetradecyl side chains) through Stille copolymerization, to yield p‐type polymer semiconductors for organic field‐effect transistor application. The electronic and structural effect of the selenium atoms, compared to sulphur atoms in analogous copolymers, is described. The molecular weight has a decisive influence on the photophysical properties and supramolecular ordering, expressed in field‐effect transistor measurements. Saturation mobilities around 10^?2 cm² · V^?1s^?1 are obtained on standard silicon substrates.

     

The cGMP synthesis and PKG1 expression in murine lymphoid organs

Numerous reports indicate that cyclic 3',5' guanosine monophosphate (cGMP) is involved in the regulation of immune processes. However, the mechanisms responsible for the synthesis of this nucleotide and its signaling pathways in immune cells are still not well recognized. The aim of our studies was to establish: 1) which form of guanylyl cyclase (GC) synthesizes cGMP in murine lymphoid organs and 2) whether the same organs express the isoforms PKG1alpha and/or PKG1beta of protein kinase G, known as possible target for synthesized cGMP. Cells isolated from thymus, lymph nodes, and spleen were treated with activators (SNP, ANP, CNP, STa) of soluble or particulate cyclases. Sodium nitroprusside (SNP) elevated intracellular cGMP 2-fold in thymic and lymph node cells and about 10-fold in spleen cells. Atrial natriuretic peptide (ANP) caused modest but statistically significant increases of cGMP in cells of all three organs. Additionally, spleen cells elevated their cGMP content about 2-fold in response to C-type natriuretic protein (CNP). In cellular homogenates of the all analyzed organs, the antibody anti-PKG1beta stained the 78 kDa band corresponding to the molecular mass of PKG1. Only homogenates of spleen cells were stained by the antibody recognizing PKG1alpha. Our results indicate that in the investigated organs cGMP may be synthesized mainly by soluble GC in response to nitric oxide. The modest increase of cGMP upon stimulation by ANP suggests that in all these organs either exists only a small subpopulation of cells that express particulate cyclase GC-A or GC-A is expressed at very low level. In spleen cells, however, cyclase GC-B appears to be the more active enzyme. Elevated cGMP concentration may in turn activate PKG1beta in thymus, lymph node, and spleen cells and also PKG1alpha in spleen cells.     

Solvent effects on free-radical polymerization, 5. Analysis of homopolymerization rate on the basis of the reactant-solvent complex model

The rate of polymerization was described as a function of the monomer concentration of 36 monomer/solvent systems in terms of the reactant-solvent complex (RSC) model. One-, two-and three-parameter optimization procedures were used to fit the rate function to experimental data. Fitting increments were the complex equilibrium constant K and the relative monomer reactivity parameter r₁₁. Irrespective of the optimization procedure, K and r₁₁, were found to correlate with the monomer exponent n and to be K = 0 and r₁₁, = 1 at n = 1. In these cases the RSC model reduces to the classical rate model. Despite the weak character of the monomer (radical)/solvent complexation, this interaction should not be neglected in rate modelling. The RSC model is a convenient tool to describe the chain propagation separately.     

An ultrasonographic monitoring of skin condition in patients receiving radiotherapy for head and neck cancers

Radiodermatitis is one of the commonest side effects of radiotherapy. They are usually assessed by semi‐quantitative clinical scores, which are not validated and may be subject to inter‐observer variability. A few previous studies suggested that high‐frequency ultrasonography (HF‐USG) is useful in the assessment of the acute phase of radiation dermatitis in breast cancer patients. (a) To monitor skin changes by HF‐USG during the course of radiotherapy due to head and neck cancers, and (b) to determine whether there is any connection between skin sonograms and the skin scoring criteria. This prospective, observational study includes patients diagnosed with head and neck cancers, treated with radiotherapy or concomitant chemoradiation. The final analysis includes six patients. In every patient, the HF‐USG as well as dermatological assessment (target lesion score—TLS and CACE v. 4.0) were performed 4×: before, in the middle, day after, and 3 months after radiotherapy. There were significant differences between non‐irradiated skin thickness and thickness of skin with clinically obvious radiodermatitis (TLS grade 1‐4; P < .0001), as well as between irradiated, unchanged skin thickness (TLS grade 0) and thickness of skin with clinically obvious radiodermatitis (TLS grade 1‐4; P = .0002). There was no significant difference between non‐irradiated and irradiated, unchanged skin thickness (TLS grade 0; P = .9318). In four patients, we demonstrated subepidermal low echogenic band (SLEB). HF‐USG can be useful tool to noninvasive and objective assessment of skin changes during radiotherapy.     

Total left main coronary artery occlusion in a female patient after AVSD surgical repair in childhood as a cause of non ST elevation myocardial infarction

A case of a 51-year-old woman with symptoms of non-ST-segment elevation acute coronary syndrome and concomitant atrial flutter is presented. Patient underwent atrioventricular septal defect repair in childhood. Coronary angiography showed total occlusion of left main coronary artery and massive collateral network originating from right coronary artery supplying entire left coronary artery. Ablation of atrial flutter had been performed and patient was subsequently submitted to mitral valve replacement, tricuspid valvuloplasty and coronary artery bypass grafting. The potential causes of left main occlusion are in this case discussed.     

All near-infrared multiparametric luminescence thermometry using Er3+, Yb3+-doped YAG nanoparticles

This paper presents four new temperature readout approaches to luminescence nanothermometry in spectral regions of biological transparency demonstrated on Yb³⁺/Er³⁺-doped yttrium aluminum garnet nanoparticles. Under the 10 638 cm⁻¹ excitation, down-shifting near infrared emissions (>10 000 cm⁻¹) are identified as those originating from Yb³⁺ ions'' ²F_5/2 → ²F_7/2 (∼9709 cm⁻¹) and Er³⁺ ions'' ⁴I_13/2 → ⁴I_15/2 (∼6494 cm⁻¹) electronic transitions and used for 4 conceptually different luminescence thermometry approaches. Observed variations in luminescence parameters with temperature offered an exceptional base for studying multiparametric temperature readouts. These include the temperature-dependence of: (i) intensity ratio between emissions from Stark components of Er^{3+ 4}I_13/2 level; (ii) intensity ratio between emissions of Yb³⁺ (²F_5/2 → ²F_7/2 transition) and Er³⁺ (⁴I_13/2 → ⁴I_15/2 transition); (iii) band shift and bandwidth and (iv) lifetime of the Yb³⁺ emission (²F_5/2 → ²F_7/2 transition) with maximal sensitivities of 1% K⁻¹, 0.8% K⁻¹, 0.09 cm⁻¹ K⁻¹, 0.46% K⁻¹ and 0.86% K⁻¹, respectively. The multimodal temperature readout provided by this material enables its application in different luminescence thermometry setups as well as improved the reliability of the temperature sensing by the cross-validation between measurements.

Four completely new NIR luminescence temperature readouts in the second and third biological windows are demonstrated with YAG:Er³⁺, Yb³⁺ nanoparticles.     

Non‐invasive left ventricular myocardial work indices in healthy adolescents at rest

Global myocardial work (GMW) provides a metric of left ventricular (LV) function and energy consumption. Its non-invasive assessment by echocardiography correlates with invasive measures and normal values have been reported in healthy adults. We aimed to establish normal values in a healthy adolescent population. Fifty-two healthy adolescents (mean age?=?14.5?±?2.0 years, range 11–19 years, 62% male) with normal echocardiograms were included. Brachial cuff blood pressure was obtained immediately following apical imaging in the supine position. Post-processing of echocardiograms for speckle tracking strain measurement and derivation of global myocardial work indices from LV pressure–strain loops was performed. The mean global work index (GWI) was 1802.0?±?264.4 mmHg% with mean global work efficiency of 95.5?±?1.1%. The mean global constructive work (GCW) was 2054.5?±?297.3 mmHg%, and the mean global wasted work 83.8?±?28.1 mmHg%. On multivariable analysis, there were significant associations between both GWI and GCW with systolic blood pressure (β coefficient?=?0.57, p?<?0.001; β coefficient?=?0.67, p?<?0.001 respectively) and LV global longitudinal strain (GLS) (β coefficient = ? 0.56, p?<?0.001; β coefficient = ? 0.52, p?<?0.001 respectively). There were no associations with any of the work indices with age, sex, body surface area, heart rate or LV ejection fraction. This study provides echocardiographic reference ranges for non-invasive indices of GMW in normal adolescents.