Random-phase Approximation Treatment Of Edge Magnetoplasmons: Edge-state Screening And Nonlocality

A random-phase approximation (RPA) treatment of edge magnetoplasmons (EMP) is presented for strong magnetic fields, low temperatures, and integer filling factors \nu. It is valid for negligible dissipation and lateral confining potentials smooth on the scale of the magnetic length \ell_{0} but sufficiently steep that the Landau-level (LL) flattening can be neglected. LL coupling, screening by edge states, and nonlocal contributions to the current density are taken into account. In addition to the fundamental mode with typical dispersion relation \omega\sim q_x \ln(q_{x}), fundamental modes with {\it acoustic} dispersion relation \omega\sim q_x are obtained for \nu>2. For \nu=1,2 a {\bf dipole} mode exists, with dispersion relation \omega\sim q_x^3, that is directly related to nonlocal responses.Comment: Text 12 pages in Latex/Revtex format, 4 Postscript figure

A Novel Signaling Network Essential for Regulating Pseudomonas aeruginosa Biofilm Development

The important human pathogen Pseudomonas aeruginosa has been linked to numerous biofilm-related chronic infections. Here, we demonstrate that biofilm formation following the transition to the surface attached lifestyle is regulated by three previously undescribed two-component systems: BfiSR (PA4196-4197) harboring an RpoD-like domain, an OmpR-like BfmSR (PA4101-4102), and MifSR (PA5511-5512) belonging to the family of NtrC-like transcriptional regulators. These two-component systems become sequentially phosphorylated during biofilm formation. Inactivation of bfiS, bfmR, and mifR arrested biofilm formation at the transition to the irreversible attachment, maturation-1 and -2 stages, respectively, as indicated by analyses of biofilm architecture, and protein and phosphoprotein patterns. Moreover, discontinuation of bfiS, bfmR, and mifR expression in established biofilms resulted in the collapse of biofilms to an earlier developmental stage, indicating a requirement for these regulatory systems for the development and maintenance of normal biofilm architecture. Interestingly, inactivation did not affect planktonic growth, motility, polysaccharide production, or initial attachment. Further, we demonstrate the interdependency of this two-component systems network with GacS (PA0928), which was found to play a dual role in biofilm formation. This work describes a novel signal transduction network regulating committed biofilm developmental steps following attachment, in which phosphorelays and two sigma factor-dependent response regulators appear to be key components of the regulatory machinery that coordinates gene expression during P. aeruginosa biofilm development in response to environmental cues

Histone Deacetylase Inhibitors Selectively Target Homology Dependent DNA Repair Defective Cells and Elevate Non-Homologous Endjoining Activity

Background: We have previously used the ATAD5-luciferase high-throughput screening assay to identify genotoxic compounds with potential chemotherapeutic capabilities. The successful identification of known genotoxic agents, including the histone deacetylase inhibitor (HDACi) trichostatin A (TSA), confirmed the specificity of the screen since TSA has been widely studied for its ability to cause apoptosis in cancer cells. Because many cancers have acquired mutations in DNA damage checkpoints or repair pathways, we hypothesized that these cancers may be susceptible to treatments that target compensatory pathways. Here, we used a panel of isogenic chicken DT40 B lymphocyte mutant and human cell lines to investigate the ability of TSA to define selective pathways that promote HDACi toxicity. Results: HDACi induced a DNA damage response and reduced viability in all repair deficient DT40 mutants although ATM-nulls were least affected. The most dramatic sensitivity was observed in mutants lacking the homology dependent repair (HDR) factor BLM or the non-homologous end-joining (NHEJ) and HDR factors, KU/RAD54, suggesting an involvement of either HDR or NHEJ in HDACi-induced cell death. To extend these findings, we measured the frequencies of HDR and NHEJ after HDACi treatment and monitored viability in human cell lines comparably deficient in HDR or NHEJ. Although no difference in HDR frequency was observed between HDACi treated and untreated cells, HDR-defective human cell lines were clearly more sensitive than wild type. Unexpectedly, cells treated with HDACis showed a significantly elevated NHEJ frequency. Conclusions: HDACi targeting drugs induced significant increases in NHEJ activity in human cell lines but did not alter HDR frequency. Moreover, HDR is required for cellular resistance to HDACi therapy; therefore, NHEJ does not appear to be a critical axis for HDACi resistance. Rather, HDACi compounds induced DNA damage, most likely double strand breaks (DSBs), and HDR proficiency is correlated with cell survivalclose4

COMPLEX DISORDERS OF HEART RHYTHM AND CONDUCTIVITY IN A PATIENT WITH HYPOTHYROIDISM (CLINICAL OBSERVATION)

The article describes a clinical case of the occurrence of complex disorders of the heart rhythm and conductivity in a patient of 45 years with decompensated hypothyroidism. The literature data on specific cardiomyopathy appearing in patients with hypothyroidism (“hypothyroid heart”), metabolic, hemodynamic changes against the background of hypothyroidism and possible violations of heart rhythm and conductivity are given. In the described clinical case the patient’s medical history is given, who has been observed in an endocrinologist for hypothyroidism for the last 3 years. 6 months before this hospitalization patient stopped taking levothyroxine on her own initiative. She noticed deterioration in the last 3 months: the clinic of hypothyroidism appeared and began to grow, a frequent extrasystole appeared. At an objective survey — a symptomatology of the expressed hypothyroidism. A comprehensive examination of the patient was performed, which revealed atrioventricular blockade of the 1st degree, frequent ventricular extrasystole, prolongation of the QT interval on the ECG, late ventricular potentials against the background of low concentrations of sodium and potassium in the blood. During the first 24 hours of hospitalization, there was a clinical death. A clear positive dynamics was traced against the background of therapy aimed at the correction of electrolyte disorders, as well as hormone replacement therapy with levothyroxine

Quality of life, symptom profile and clinical efficacy of second-line treatment with dasatinib in patients with imatinib-resistant or -intolerant chronic myeloid leukemia: results of 2-year follow-up

The article is focused on the results of the multicenter observational study “Quality of life and symptom profile in patients with chronic myeloid leukemia in chronic phase in long-term follow-up of second-line treatment” (2012–2015). Thirty imatinib-resistant or-intolerant patients with chronic myeloid leukemia in chronic phase were observed in the real-world clinical setting during 24 months after start of second-line treatment with dasatinib. Mean age – 48 years old (SD = 13.1); males / females – 14 / 16; one third of patients were with comorbidity, Charlson Index – 0–5 scores. All the patients received dasatinib in the dosage of 100 mg daily. Study time points – 12, 18 and 24 months after second-line treatment start. Treatment outcomes were analyzed in terms of clinical efficacy and safety as well as in terms of patient-reported outcomes, including quality of life and symptom profile assessment. For quality of life and symptom assessment the SF-36 and CSP-CML questionnaires were used, respectively. Statisticallly significant changes in quality of life and symptom severity were analyzed by generalized estimated equation (GEE). Complete hematological response was observed in 96.3 % patients, complete cytogenetic response – in 66.6 % patients, complete or major molecular response – in 60 % patients. The acceptable tolerability of dasatinib treatment was shown during long-term follow-up: hematological and non-hematological serious adverse events were rare and didn’t lead to treatment discontinuation. Significant improvement of physical functioning, role physical functioning, role emotional functioning, vitality and mental health as compared to base-line parameters was observed (p < 0.05). The severity of a number pronounced symptoms decreased and the proportion of patients with severe symptoms reduced (p = 0.01) after 24 months of second-line treatment start. Quality of life treatment response in terms of stabilization or improvement was registered in 83 % of patients. The data of this real-world study in CML patients are in line with the results of clinical studies in terms of dasatinib treatment efficacy and safety. In addition, they demonstrate the value of patient-reported outcomes to evaluate benefits and risks of long-term dasatinib treatment from patient perspective