555 research outputs found

    Захисні лісові насадження – важливий структурний елемент у формуванні національної екологічної мережі

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    Описано роль і значення захисних лісових насаджень як важливого структурного елементу при формуванні національної екологічної мережі.Описана роль и значение защитных лесных насаждений как важного структурного элемента при формировании национальной экологической сети.Role and meaning of forest protective stands as an important structural element for national ecological network formation is described

    High-Frequency network activity, global increase in Neuronal Activity, and Synchrony Expansion Precede Epileptic Seizures In Vitro

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    How seizures start is a major question in epilepsy research. Preictal EEG changes occur in both human patients and animal models, but their underlying mechanisms and relationship with seizure initiation remain unknown. Here we demonstrate the existence, in the hippocampal CA1 region, of a preictal state characterized by the progressive and global increase in neuronal activity associated with a widespread buildup of low-amplitude high-frequency activity (HFA) (100 Hz) and reduction in system complexity.HFAis generated by the firing of neurons, mainly pyramidal cells, at much lower frequencies. Individual cycles ofHFAare generated by the near-synchronous (within 5 ms) firing of small numbers of pyramidal cells. The presence of HFA in the low-calcium model implicates nonsynaptic synchronization; the presence of very similar HFA in the high-potassium model shows that it does not depend on an absence of synaptic transmission. Immediately before seizure onset, CA1 is in a state of high sensitivity in which weak depolarizing or synchronizing perturbations can trigger seizures. Transition to seizure is haracterized by a rapid expansion and fusion of the neuronal populations responsible for HFA, associated with a progressive slowing of HFA, leading to a single, massive, hypersynchronous cluster generating the high-amplitude low-frequency activity of the seizure

    The Lymnaea Cardioexcitatory Peptide (LyCEP) Receptor: A G-Protein–Coupled Receptor for a Novel Member of the RFamide Neuropeptide Family

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    A novel G-protein–coupled receptor (GRL106) resembling neuropeptide Y and tachykinin receptors was cloned from the molluscLymnaea stagnalis. Application of a peptide extract from the Lymnaea brain to Xenopus oocytes expressing GRL106 activated a calcium-dependent chloride channel. Using this response as a bioassay, we purified the ligand for GRL106,Lymnaea cardioexcitatory peptide (LyCEP), an RFamide-type decapeptide (TPHWRPQGRF-NH2) displaying significant similarity to the Achatina cardioexcitatory peptide (ACEP-1) as well as to the recently identified family of mammalian prolactin-releasing peptides. In the Lymnaeabrain, the cells that produce egg-laying hormone are the predominant site of GRL106 gene expression and appear to be innervated by LyCEP-containing fibers. Indeed, LyCEP application transiently hyperpolarizes isolated egg-laying hormone cells. In theLymnaea pericardium, LyCEP-containing fibers end blindly at the pericardial lumen, and the heart is stimulated by LyCEPin vitro. These data confirm that LyCEP is an RFamide ligand for GRL10

    R-h-erythropoietin counteracts the inhibition of in vitro erythropoiesis by tumour necrosis factor alpha in patients with rheumatoid arthritis

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    Anaemia of chronic disease (ACD) is a common extra-articular manifestation of rheumatoid arthritis (RA). Tumour necrosis factor alpha (TNFα) plays an important role in the development of ACD. The objective of the present study was to assess inhibition of in vitro colony-forming unit erythrocyte (CFUe) and blast-forming unit erythrocyte (BFUe) growth by TNFα and to examine whether this suppression could be counteracted by adding increasing concentrations of recombinant human erythropoietin (EPO) (r-h-EPO) to bone marrow cultures of RA patients with ACD and without anaemia (controls). Bone marrow cells of RA patients with ACD and control patients were cultured. The cultures were incubated with increasing concentrations of r-h-EPO (0.25; 0.5; 1; 2 U/ml), each in combination with increasing quantities of TFNα (0; 50; 100; 200; 400 U/ml). CFUe and BFUe were assessed after 7 and 14 days, respectively. Dose-dependent inhibition of BFUe and CFUc by increasing concentrations of TNFα was observed in ACD and controls. Regarding CFUe (ACD patients) incubated with 0.25 U/ml EPO, 50 U/ml TNFα caused 28% suppression compared to cultures without TNFα. Increasing the concentration of r-h-EPO from 0.25 U/ml to 2 U/ml completely restored the number of CFUe. A similar pattern was observed in BFUe growth in both groups. These data demonstrated the suppressive effects of TNFα on erythropoiesis in vitro and that the suppresed erythropoiesis could be partly corrected by the addition of excess r-h-EPO to the cultures. No significant differences were observed between ACD and control RA patients. This in vitro model may help explain the clinical response to r-h-EPO therapy as documented in RA patients with ACD

    IL-6-induced anaemia in rats:Possible pathogenetic implications for anaemia observed in chronic inflammations

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    Anaemia of chronic disease (ACD) is frequently found in rheumatoid arthritis (RA). In the pathogenesis of ACD both cytokines, such as tumour necrosis factor-alpha (TNF-α), IL-1 and IL-6 as well as a relative deficiency of erythropoietin (EPO), are thought to play a key role. In the present study the role of IL-6 in the pathogenesis of this anaemia was investigated. IL-6 was administered intraperitoneally to rats for 14 sequential days. It appeared that IL-6 was able to induce anaemia. No evidence for suppression of bone marrow erythropoiesis or enhanced sequestration of erythrocytes in the liver was found. However, decreased plasma and bone marrow iron contents were observed in anaemic rats. Blood loss in intestinal tissue was demonstrated using erythrocyte labelling with 99mtechnetium. Histologically this was associated with inflammatory cell infiltration, oedema and bleeding in the intestinal wall. In conclusion, IL-6 induced anaemia in rats. This anaemia was caused by intestinal blood loss.</p

    Ferric carboxymaltose versus ferrous fumarate in anemic children with inflammatory bowel disease:the POPEYE randomized controlled clinical trial

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    OBJECTIVE: To determine whether intravenous (IV) or oral iron suppletion is superior in improving physical fitness in anemic children with inflammatory bowel disease (IBD).STUDY DESIGN: We conducted a clinical trial at 11 centers. Children aged 8 to 18 with IBD and anemia (defined as hemoglobin (Hb) z-score &lt; -2) were randomly assigned to a single IV dose of ferric carboxymaltose or 12 weeks of oral ferrous fumarate. Primary endpoint was the change in 6-minute walking distance (6MWD) from baseline, expressed as z-score. Secondary outcome was a change in Hb z-score from baseline.RESULTS: We randomized 64 patients (33 IV iron; 31 oral iron) and followed them for 6 months. One month after the start of iron therapy, the 6MWD z-score of patients in the IV group had increased by 0.71 compared with -0.11 in the oral group (P=0.01). At 3- and 6-months follow-up, no significant differences in 6MWD z-scores were observed. Hb z-scores gradually increased in both groups and the rate of increase was not different between groups at 1, 3 and 6 months after initiation of iron therapy (overall P=0.97).CONCLUSION: In this trial involving anemic children with IBD, a single dose of IV ferric carboxymaltose was superior to oral ferrous fumarate with respect to quick improvement of physical fitness. At 3 and 6 months after initiation of therapy, no differences were discovered between oral or IV therapy. The increase of Hb over time was comparable in both treatment groups.TRIAL REGISTRATION: NTR4487 [Netherlands Trial Registry].</p
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