Effectiveness of beta-blockers in the treatment of idiopathic premature ventricular contractions in children

Aim. To evaluate the effectiveness of beta-blockers (BB) in the treatment of idiopathic premature ventricular contractions (PVCs) in children.Material and methods. BBs were prescribed to 27 children with idiopathic PVCs. In 3 (11,1%) patients, side effects (hypotension, bronchial obstruction) was revealed at the beginning of therapy. A total of 24 children were included in the further study (15 boys (62,5%), 9 girls (37,5%). The mean age was 8,3±5,4 years. Data from anamnesis, electrocardiography (ECG), 24-hour ECG monitoring, and echocardiography were analyzed.Results. The 24-hour PVC rate was 33,2±17,7 thousand/day or 26,6±13,2%. In 14 (58,3%) children, we recorded paired PVCs, in 3 (12,5%) — multiform, in 10 (41,7%) — runs of non-sustained VT. There were complaints in 7 (29,2%) children. The follow-up period lasted 369,8±119,1 days. Propranolol was received by 17 (70,8%) patients, metoprolol — by 7 (29,2%). The therapy was effective in 11 (45,8%) patients, while ineffective in 13 (54,2%), among which 5 (20,8%) had an increase in the number of PVCs. The effectiveness of BBs was higher in children under the age of 1 year (p=0,043). Propranolol showed greater efficacy than metoprolol (p=0,047). Less efficiency was observed in female patients and those with pathological heart rate turbulence parameters (p=0,04).Conclusion. The effectiveness of BBs in children with idiopathic PVCs is 45,8%, higher in children aged <1 year and declines with age, decreasing in adolescents to 25%. The use of BBs is limited by non-cardiac side effects in 11,1% of children. Propranolol is more effective than metoprolol

Hemolysis and ATP release from human and rat erythrocytes under conditions of hypoxia: a comparative study

Red blood cells are involved not only in transportation of oxygen and carbon dioxide but also in autoregulation of vascular tone by ATP release in hypoxic conditions. Molecular mechanisms of the ATP release from red blood cells in response to a decrease in partial oxygen pressure still remain to be elucidated. In this work we have studied effects of hypoxia on red blood cell hemolysis in humans and rats and compared the effects of inhibitors of ecto-ATPase and pannexin on the release of ATP and hemoglobin from rat erythrocytes. The 20-min hypoxia at 37°C increased hemolysis of red blood cells in humans and rats 1.5- and 2.5-fold, respectively. In rat erythrocytes a significant increase in hypoxia-induced extracellular ATP level was found only in the presence of ecto-ATPase inhibitor ARL 67156. In these conditions we observed a positive correlation (R2 = 0.5003) between the increase in free hemoglobin concentration and the ATP release. Neither carbenoxolon nor probenecid, the inhibitors of low-selectivity pannexin channels, altered the hypoxia-induced ATP release from rat erythrocytes. The obtained results indicate a key role of hemolysis in the ATP release from red blood cells

Subsets of cerebrospinal fluid lymphocytes in acute pediatric respiratory viral infection with meningeal syndrome

Current urgency of studying the intrathecal cellular immune response to infections of central nervous system is determined by limited knowledge on existing data about mechanisms of the brain immune protection in normal and diseased state. Implication of multi-colour flow cytometry in clinical laboratory diagnostics allowed to perform detailed studies of biological liquors, including cerebrospinal fluid (CSF). Currently, however, there are only scarce data on the lymphocyte subpopulations in CSF. Appropriate reference values remain a challenging issue. A study of CSF lymphocyte pool in absence of definite results at previous examination may be a potential way to resolve this problem. These clinical conditions include acute respiratory viral infections (ARVI), presenting with pseudomeningitidis (meningism) syndrome. The aim of this work was to characterize the subsets of lymphocytes from CSF of the children with ARVI with the meningism symptoms in order to get basic (control) values for diagnostics of inflammatory brain diseases. We have studied subpopulation composition of the CSF lymphocytes form in 27 children with ARVI complicated by the meningism (pseudomeningitidis) by means of flow cytometry using FACSCalibur analyzer with BD MultiTEST IMK Kit reagents. The data evaluation was performed with FlowJo software. We have studied relative contents of the main subsets, i.e., total Т cells (CD3+); Т helpers (CD3+CD4+Th); cytotoxic T cells (CD3+CD8+CTL); natural killers (СD3-CD16+CD56+NK); В cells (CD3-CD19+), and minor lymphocyte subpopulations: double-positive (DP) (CD3+CD4+CD8+); double-negative (DN) (CD3+CD4-CD8-) T cells; NKT (СD3+CD16+CD56+); CD3+CD8bright, CD3+CD8dim, CD3-CD8+NK. Statistical evaluation was carried out with standard GraphPad Prism 5 software. Among the main lymphocyte populations in CSF, T cell were predominant (96.2%), as well as their subpopulations, i.e., CD4Th (53.4%), and CD8+CTL (28.2%), with low amounts of NK (2.2%) and B cells (0.7%). The mean relative content of minor subpopulations (DN or DP T cells, and NKT cells) was, respectively, 5.3, 4.0, and 9%. Age dependence was revealed for the contents of major and minor lymphocyte subsets. With advancing age of the children, the relative numbers of CD3+ and CD4+Тh cells in CSF increase, as well as CD4/CD8 ratio, associated with decreased share of NK cells, like as DN and CD3+CD8dimТ cells. The results obtained are reflect some features of lymphocyte pool in CSF of the children without inflammatory process in CNS. Thus, they may be referred as control values (inflammation-free brain disorders) when studying immune pathogenesis of neuroinfections and other inflammatory diseases of CNS in the children from different age groups

Analysis of the application of the optical method to the measurements of the water vapor content in the atmosphere - Part 1: Basic concepts of the measurement technique

We retrieved the total content of the atmospheric water vapor (or Integrated Water Vapor, IWV) from extensive sets of photometric data obtained since 1995 at Lindenberg Meteorological Observatory with star and sun photometers. Different methods of determination of the empirical parameters that are necessary for the retrieval are discussed. The instruments were independently calibrated using laboratory measurements made at Pulkovo Observatory with the VKM-100 multi-pass vacuum cell. The empirical parameters were also calculated by the simulation of the atmospheric absorption by water vapor, using the MODRAN-4 program package for different model atmospheres. The results are compared to those presented in the literature, obtained with different instruments and methods of the retrieval. The reliability of the empirical parameters, used for the power approximation that links the water vapor content with the observed absorption, is analyzed. Currently, the total (from measurements, calibration, and calculations) errors yield the standard uncertainty of about 10% in the total column water vapor. We discuss the possibilities for improving the accuracy of calibration to ~1% as indispensable condition in order to make it possible to use data obtained by optical photometry as an independent reference for other methods (GPS, MW-radiometers, lidar, etc).Comment: 28 pages, 8 figures, 3 tables. In submitting to Atmospheric Measurement Technique

A study on L-threonine and L-serine uptake in Escherichia coli K-12

In the current study, we report the identification and characterization of the yifK gene product as a novel amino acid carrier in E. coli K-12 cells. Both phenotypic and biochemical analyses showed that YifK acts as a permease specific to L-threonine and, to a lesser extent, L-serine. An assay of the effect of uncouplers and composition of the reaction medium on the transport activity indicates that YifK utilizes a proton motive force to energize substrate uptake. To identify the remaining threonine carriers, we screened a genomic library prepared from the yifK-mutant strain and found that brnQ acts as a multicopy suppressor of the threonine transport defect caused by yifK disruption. Our results indicate that BrnQ is directly involved in threonine uptake as a low-affinity but high-flux transporter, which forms the main entry point when the threonine concentration in the external environment reaches a toxic level. By abolishing YifK and BrnQ activity, we unmasked and quantified the threonine transport activity of the LIV-I branched chain amino acid transport system and demonstrated that LIV-I contributes significantly to total threonine uptake. However, this contribution is likely smaller than that of YifK. We also observed the serine transport activity of LIV-I, which was much lower compared with that of the dedicated SdaC carrier, indicating that LIV-I plays a minor role in the serine uptake. Overall, these findings allow us to propose a comprehensive model of the threonine/serine uptakesubsystem in E. coli cells

Analyticity, Crossing Symmetry and the Limits of Chiral Perturbation Theory

The chiral Lagrangian for Goldstone boson scattering is a power series expansion in numbers of derivatives. Each successive term is suppressed by powers of a scale, $\Lambda_\chi$, which must be less than of order $4\pi f/\sqrt{N}$ where $f$ is the Goldstone boson decay constant and $N$ is the number of flavors. The chiral expansion therefore breaks down at or below $4 \pi f/\sqrt{N}$. We argue that the breakdown of the chiral expansion is associated with the appearance of physical states other than Goldstone bosons. Because of crossing symmetry, some ``isospin'' channels will deviate from their low energy behavior well before they approach the scale at which their low energy amplitudes would violate unitarity. We argue that the estimates of ``oblique'' corrections from technicolor obtained by scaling from QCD are untrustworthy.Comment: harvmac, 18 pages (3 figures), HUTP-92/A025, BUHEP-92-18, new version fixes a TeX problem in little mod

Efficacy and safety of diacerein in patients with knee osteoarthritis

Diacerein (D) belongs to a class of symptomatic slow-acting agents, has an original mechanism of action, and is widely used as a diseasemodifying antirheumatic drug to treat osteoarthritis (OA) in Russia and many countries of the world. The ability of the drug to affect the main symptoms and progression of OA has been shown in a number of well-organized clinical trials.Objective: to evaluate the efficacy and safety of D in patients with knee OA.Patients and methods. An open-label trial evaluating the efficacy and safety of D (diaflex) in patients with knee OA was conducted in accordance with the multicenter program «Osteoarthrosis: Assessment of Progression in Real Clinical Practice». The trial included 80 patients of both sexes with Stage II–III knee OA; mean age, 60.8±6.8 years (47–75 years); mean body mass index, 31.8±5.9 kg/m2; disease duration, 10.3±5.7 years (2–30 years). The duration of the trial was 9 months (6 months of therapy and 3 months of follow-up).Results. There was a statistically significant reduction in visual analog scale pain on walking just 1 month after therapy initiation (57.1±9.7 and 44.7±13.9 mm; p<0.0001) and a further significant improvement throughout the 6-month therapy. Pain did not increase after the drug was discontinued (the follow-up period was 3 months). The same pattern was observed in the assessment of the WOMAC index (pain during early therapy, 243.8±73.9; pain at the end of therapy, 137.5±78.9; stiffness, 97.8±41.1 and 57.7±38.6; functional failure, 875.8±250.4 and 525±305.7 respectively; p<0.0001). Statistically significantly improved quality of life indicators measured by EQ-5D were noted throughout the follow-up period: 0.43±0.23 at the beginning of therapy, 0.61±0.14 at its end, and 0.63±0.11 at 3 months following treatment completion (p<0.0001). By the time of therapy completion, 71.3% of the patients completely refused to take nonsteroidal anti-inflammatory drugs (NSAIDs). Both the patient and the physician evaluated the efficiency of treatment identically. By the end of therapy, 87.5% of the patients were observed to have improvement. Adverse reactions (ARs) were recorded in 10 (12.5%) patients and mainly associated with more frequent stools; ARs were not a cause of treatment interruptions or protocol deviations.Conclusion. Diaflex has a good symptomatic and anti-inflammatory effect: the therapy statistically significantly reduces pain, stiffness, and the need for NSAIDs and improves quality of life and joint function. The drug has a good safety profile and after-effects, which is seen at least 3 months after therapy discontinuation