Spiking-bursting activity in the thalamic reticular nucleus initiates sequences of spindle oscillations in thalamic networks

Recent intracellular and local field potential recordings from thalamic reticular (RE) neurons in vivo as well as computational modeling of the isolated RE nucleus suggest that, at relatively hyperpolarized levels of membrane potentials, the inhibitory postsynaptic potentials (IPSPs) between RE cells can be reversed and gamma-aminobutyric acid-A (GABA(A)) -mediated depolarization can generate persistent spatio-temporal patterns in the RE nucleus. Here we investigate how this activity affects the spatio-temporal properties of spindle oscillations with computer models of interacting RE and thalamocortical (TC) cells. In a one-dimensional network of RE and TC cells, sequences of spindle oscillations alternated with localized patterns of spike-burst activity propagating inside the RE network. New sequences of spindle oscillations were initiated after removal of I(h)-mediated depolarization of the TC cells. The length of the interspindle lulls depended on the intrinsic and synaptic properties of RE and TC cells and was in the range of 3-20 s. In a two-dimensional model, GABA(A)-mediated 2-3 Hz oscillations persisted in the RE nucleus during interspindle lulls and initiated spindle sequences at many foci within the RE-TC network simultaneously. This model predicts that the intrinsic properties of the reticular thalamus may contribute to the synchrony of spindle oscillations observed in vivo.     

New results concerning the plum pox virus epidemiology and resistance of plum cultivars, hybrids and rootstocks

Our recent results on the plum pox virus (PPV) epidemiology show that PPV spreads very rapidly in plum tree plantations in the contaminated areas. A clearing of the PPV-infected trees reduces significantly the spread of the virus but does not eliminate the disease. Some plum tree cultivars, hybrids and rootstocks (Scoldus, Alina, Cristi, BN 1/8Fl, BN 2Gr. etc) showing field resistance could not be infected with PPV by natural way. However, they could be infected with PPV by artificial inoculation except for the plum tree cv. Local of Dragasani and the BN 4Kr myrobalan, which proved to be immune to PPV. PPV was not transmitted through seeds in plum tree and myrobalan in the nursery. The Hyalopterus pruni aphids were found PPV-positive by an enzyme-linked immunosorbent assay (ELISA).     

Energetics of blood flow in Fontan circulation under VAD support

The need to simulate the normal operating conditions of the human body is the key factor in every study and engineering process of bioelectronic devices designed for implantation. The Fontan procedure is an example of such a process aimed to support the human body function. It is a standard treatment method for patients with a functionally univentricular heart. However, it has significant drawbacks such as overload of the only functional heart ventricle that often leads to the necessity of the heart transplantation. In this study, we analyze the total cavopulmonary connection (TCPC) influence on the blood with and without connected auxiliary blood circulation pump. We investigate four different types of TCPC configurations, analyze blood pressure and different flow rate, study the turbulent kinetic energy distribution, and evaluate hydraulic and power losses for various cases. Finally, we calculate volumetric scalar shear stresses distribution and demonstrate the high potential of TCPC configuration with connected rotary pump as a tool for the load redistribution in the functional heart ventricle. This work is particularly relevant for improving existing TCPCs’ quality that can extend the life of Fontan patients. Moreover, it also applies to the reduction of morbidity and mortality of the patients waiting for the heart transplantation.     

Riboxine effectiveness in combined treatment of chronic atrophic gastritis

The authors present results of combined treatment of 60 patients with chronic atrophic gastritis with riboxine. A favorable effect was registered on clinical symptoms, acid-forming function, ultrastructure of gastric mucosa. The above positive effects of riboxine make it useful in combined treatment of chronic atrophic gastritis.     

Bentonite toxicology and epidemiology – a review

Bentonite, a clay with numerous industrial and consumer applications, is mined and processed in many countries of the world. Its many beneficial uses also create the potential for widespread occupational and consumer exposure. The available studies on toxicity and epidemiology indicate that the principal exposure pathway of concern is inhalation of respirable dust by occupationally exposed cohorts. Bentonite itself is probably not more toxic than any other particulate not otherwise regulated and is not classified as a carcinogen by any regulatory or advisory body, but some bentonite may contain variable amounts of respirable crystalline silica, a recognized human carcinogen. Therefore, prudent management and adherence to occupational exposure limits is appropriate. This review summarizes the literature available on production, applications, exposure, toxicity, and epidemiology of bentonite and identifies data gaps and limitations.     

Presynaptic Ca2+ buffers control the strength of a fast post-tetanic hyperpolarization mediated by the alpha3 Na(+)/K(+)-ATPase

The excitability of CNS presynaptic terminals after a tetanic burst of action potentials is important for synaptic plasticity. The mechanisms that regulate excitability, however, are not well understood. Using direct recordings from the rat calyx of Held terminal, we found that a fast Na(+)/K(+)-ATPase (NKA)-mediated post-tetanic hyperpolarization (PTH) controls the probability and precision of subsequent firing. Notably, increasing the concentration of internal Ca(2+) buffers or decreasing Ca(2+) influx led to larger PTH amplitudes, indicating that an increase in [Ca(2+)](i) regulates PTH via inhibition of NKAs. The characterization for the first time of a presynaptic NKA pump current, combined with immunofluorescence staining, identified the alpha3-NKA isoform on calyx terminals. Accordingly, the increased ability of the calyx to faithfully fire during a high-frequency train as it matures is paralleled by a larger expression of alpha3-NKA during development. We propose that this newly discovered Ca(2+) dependence of PTH is important in the post-burst excitability of nerve terminals.     

Connexin 43‐targeted T1 contrast agent for MRI diagnosis of glioma

Glioblastoma multiforme is the most aggressive form of brain tumor. Early and accurate diagnosis of glioma and its borders is an important step for its successful treatment. One of the promising targets for selective visualization of glioma and its margins is connexin 43 (Cx43), which is highly expressed in reactive astrocytes and migrating glioma cells. The purpose of this study was to synthesize a Gd‐based contrast agent conjugated with specific antibodies to Cx43 for efficient visualization of glioma C6 in vivo. We have prepared stable nontoxic conjugates of monoclonal antibody to Cx43 and polylysine–DTPA ligands complexed with Gd(III), which are characterized by higher T₁ relaxivity (6.5 mM^?1 s^?1 at 7 T) than the commercial agent Magnevist® (3.4 mM^?1 s^?1). Cellular uptake of Cx43‐specific T₁ contrast agent in glioma C6 cells was more than four times higher than the nonspecific IgG‐contrast agent, as detected by flow cytometry and confocal analysis. MRI experiments showed that the obtained agents could markedly enhance visualization of glioma C6 in vivo after their intravenous administration. Significant accumulation of Cx43‐targeted contrast agents in glioma and the peritumoral zone led not only to enhanced contrast but also to improved detection of the tumor periphery. Fluorescence imaging confirmed notable accumulation of Cx43‐specific conjugates in the peritumoral zone compared with nonspecific IgG conjugates at 24 h after intravenous injection. All these features of Cx43‐targeted contrast agents might be useful for more precise diagnosis of glioma and its borders by MRI. Copyright © 2015 John Wiley & Sons, Ltd.     

New-Onset Diabetes After Acute and Critical Illness: A Systematic Review

Hyperglycemia is commonly observed during acute and critical illness. Recent studies have investigated the risk of developing diabetes after acute and critical illness, but the relationship between degree of in-hospital hyperglycemia and new-onset diabetes has not been investigated. This study examines the evidence for the relationship between in-hospital hyperglycemia and prevalence of new-onset diabetes after acute and critical illness. A literature search was performed of the MEDLINE, EMBASE, and Scopus databases for relevant studies published from January 1, 2000, through August 4, 2016. Patients with no history of diabetes before hospital discharge were included in the systematic review. In-hospital glucose concentration was classified as normoglycemia, mild hyperglycemia, or severe hyperglycemia for the meta-analysis. Twenty-three studies were included in the systematic review, and 18 of these (111,078 patients) met the eligibility criteria for the meta-analysis. The prevalence of new-onset diabetes was significantly related to in-hospital glucose concentration and was 4% (95% CI, 2%-7%), 12% (95% CI, 9%-15%), and 28% (95% CI, 18%-39%) for patients with normoglycemia, mild hyperglycemia, and severe hyperglycemia, respectively. The prevalence of new-onset diabetes was not influenced by disease setting, follow-up duration, or study design. In summary, this study found stepwise growth in the prevalence of new-onset diabetes with increasing in-hospital glucose concentration. Patients with severe hyperglycemia are at the highest risk, with 28% developing diabetes after hospital discharge.