Phosphorylation of Vasodilator-Stimulated Phosphoprotein (VASP) dampens hepatic ischemia-reperfusion injury

Recent work has demonstrated that the formation of platelet neutrophil complexes (PNCs) affects inflammatory tissue injury. Vasodilator-stimulated phosphoprotein (VASP) is crucially involved into the control of PNC formation and myocardial reperfusion injury. Given the clinical importance of hepatic IR injury we pursued the role of VASP during hepatic ischemia followed by reperfusion. We report here that VASP−/− animals demonstrate reduced hepatic IR injury compared to wildtype (WT) controls. This correlated with serum levels of lactate dehydrogenase (LDH), aspartate (AST) and alanine (ALT) aminotransferase and the presence of PNCs within ischemic hepatic tissue and could be confirmed using repression of VASP through siRNA. In studies employing bone marrow chimeric mice we identified hematopoietic VASP to be of crucial importance for the extent of hepatic injury. Phosphorylation of VASP on Ser153 through Prostaglandin E1 or on Ser235 through atrial natriuretic peptide resulted in a significant reduction of hepatic IR injury. This was associated with a reduced presence of PNCs in ischemic hepatic tissue. Taken together, these studies identified VASP and VASP phosphorylation as crucial target for future hepatoprotective strategies

Proapoptotic activity of Ukrain is based on Chelidonium majus L. alkaloids and mediated via a mitochondrial death pathway

BACKGROUND: The anticancer drug Ukrain (NSC-631570) which has been specified by the manufacturer as semisynthetic derivative of the Chelidonium majus L. alkaloid chelidonine and the alkylans thiotepa was reported to exert selective cytotoxic effects on human tumour cell lines in vitro. Few clinical trials suggest beneficial effects in the treatment of human cancer. Aim of the present study was to elucidate the importance of apoptosis induction for the antineoplastic activity of Ukrain, to define the molecular mechanism of its cytotoxic effects and to identify its active constituents by mass spectrometry. METHODS: Apoptosis induction was analysed in a Jurkat T-lymphoma cell model by fluorescence microscopy (chromatin condensation and nuclear fragmentation), flow cytometry (cellular shrinkage, depolarisation of the mitochondrial membrane potential, caspase-activation) and Western blot analysis (caspase-activation). Composition of Ukrain was analysed by mass spectrometry and LC-MS coupling. RESULTS: Ukrain turned out to be a potent inducer of apoptosis. Mechanistic analyses revealed that Ukrain induced depolarisation of the mitochondrial membrane potential and activation of caspases. Lack of caspase-8, expression of cFLIP-L and resistance to death receptor ligand-induced apoptosis failed to inhibit Ukrain-induced apoptosis while lack of FADD caused a delay but not abrogation of Ukrain-induced apoptosis pointing to a death receptor independent signalling pathway. In contrast, the broad spectrum caspase-inhibitor zVAD-fmk blocked Ukrain-induced cell death. Moreover, over-expression of Bcl-2 or Bcl-x(L )and expression of dominant negative caspase-9 partially reduced Ukrain-induced apoptosis pointing to Bcl-2 controlled mitochondrial signalling events. However, mass spectrometric analysis of Ukrain failed to detect the suggested trimeric chelidonine thiophosphortriamide or putative dimeric or monomeric chelidonine thiophosphortriamide intermediates from chemical synthesis. Instead, the Chelidonium majus L. alkaloids chelidonine, sanguinarine, chelerythrine, protopine and allocryptopine were identified as major components of Ukrain. Apart from sanguinarine and chelerythrine, chelidonine turned out to be a potent inducer of apoptosis triggering cell death at concentrations of 0.001 mM, while protopine and allocryptopine were less effective. Similar to Ukrain, apoptosis signalling of chelidonine involved Bcl-2 controlled mitochondrial alterations and caspase-activation. CONCLUSION: The potent proapoptotic effects of Ukrain are not due to the suggested "Ukrain-molecule" but to the cytotoxic efficacy of Chelidonium majus L. alkaloids including chelidonine

New insights into the molecular pathology of radiation-induced pneumopathy.

Pneumonitis and fibrosis constitute dose-limiting side effects of thorax or total body irradiation. An improved understanding of the underlying mechanisms is a prerequisite for the development of effective radioprotective strategies. Here we characterized the behavior of resident and immune cells in a murine model of radiation-induced pneumopathy

Gαi2- and Gαi3-deficient mice display opposite severity of myocardial ischemia reperfusion injury.

G-protein-coupled receptors (GPCRs) are the most abundant receptors in the heart and therefore are common targets for cardiovascular therapeutics. The activated GPCRs transduce their signals via heterotrimeric G-proteins. The four major families of G-proteins identified so far are specified through their α-subunit: Gαi, Gαs, Gαq and G12/13. Gαi-proteins have been reported to protect hearts from ischemia reperfusion injury. However, determining the individual impact of Gαi2 or Gαi3 on myocardial ischemia injury has not been clarified yet. Here, we first investigated expression of Gαi2 and Gαi3 on transcriptional level by quantitative PCR and on protein level by immunoblot analysis as well as by immunofluorescence in cardiac tissues of wild-type, Gαi2-, and Gαi3-deficient mice. Gαi2 was expressed at higher levels than Gαi3 in murine hearts, and irrespective of the isoform being knocked out we observed an up regulation of the remaining Gαi-protein. Myocardial ischemia promptly regulated cardiac mRNA and with a slight delay protein levels of both Gαi2 and Gαi3, indicating important roles for both Gαi isoforms. Furthermore, ischemia reperfusion injury in Gαi2- and Gαi3-deficient mice exhibited opposite outcomes. Whereas the absence of Gαi2 significantly increased the infarct size in the heart, the absence of Gαi3 or the concomitant upregulation of Gαi2 dramatically reduced cardiac infarction. In conclusion, we demonstrate for the first time that the genetic ablation of Gαi proteins has protective or deleterious effects on cardiac ischemia reperfusion injury depending on the isoform being absent

Assessment and safety of operation of oil and gas pipelines in non-steady conditions of technological parameters

Актуальность. Изменения технологических параметров перекачки продукта в процессе эксплуатации нефтегазопроводов по сравнению со стационарными условиями работы приводят к возникновению дополнительных механических напряжений в стенке труб и к снижению запасов прочности. При этом заданный в стадии проектирования ресурс трубопроводов изменяется в сторону уменьшения. Возрастает риск возникновения аварийных ситуаций. Это обуславливает необходимость разработки методов оценки и обеспечения безопасности нефтегазопроводов в условиях нестационарности технологических параметров эксплуатации. Цель исследования: оценить и обеспечить безопасность эксплуатации нефтегазопроводов при нестационарности технологических параметров перекачки. Объект исследования: трубопроводная система нефтегазовой отрасли. Методы: теоретические исследования безопасности эксплуатации нефтегазопроводов в условиях нестационарности технологических параметров режима перекачки. Результаты. Получены аналитические зависимости запасов прочности трубопроводов от параметров нестационарности режима перекачки. Даны рекомендации по обеспечению безопасности нефтегазопроводов в условиях нестационарности технологических параметров эксплуатации. Выводы. В условиях нестанционарности технологических параметров эксплуатации нефтегазопроводов в стенке их труб возникают повышенные механические напряжения, снижающие безопасность и ресурс сооружения. При одинаковых условиях нагружения внутренним давлением наибольшие напряжения возникают в сечениях соединения трубопровода с оборудованием, имеющим абсолютную жесткость на деформацию. Снижение уровня механических напряжений в стенке труб обеспечивается плавным регулированием режима перекачки, которое реализуется на нефтепроводах с помощью магистральных насосов, оснащенных частотно-регулируемым электроприводом. Обеспечение безопасности эксплуатации нефтегазопроводов в условиях нестационарности технологических параметров перекачки может быть достигнуто регулированием режима перекачки продукта перекачивающими агрегатами, оснащенными регулируемым приводом.The relevance. Changes in technological parameters of product pumping at oil and gas pipelines operation in comparison with the stationary operating condition leads to appearance of additional mechanical stresses in the wall of pipes and to decrease in margin of safety. At the same time, the pipeline resource specified in the project changes to decrease. The risk of failures increases. This substantiates the development of methods for assessing and ensuring the safety of oil and gas pipelines in conditions of non-stationarity of technological parameters of operation. The main aim of the research is to assess and ensure the safety of operation of oil and gas pipelines at non-stationarity of pumping technological parameters. Object: pipeline system of oil and gas industry. Methods: theoretical studies of oil and gas pipeline operation safety in conditions of non-stationarity of technological parameters of the pumping regime. Results. The authors have obtained the analytical dependences of pipelines strength on parameters of non-stationarity of pumping regime and recommended to ensure safety of oil and gas pipelines in conditions of non-stationarity of technological operating parameters. Conclusions. In non-stationarity conditions of oil and gas pipelines technological parameters while operation, in the wall of their pipes, the increased mechanical stresses occur that reduce the safety and life of the structure. Under the same conditions of inner pressure, the highest stresses arise in section of pipeline connection with equipment which have absolute rigidity for deformation. Mechanical stresses reduction in pipeline wall is provided by pumping regime smooth regulation, which is realized on oil pipelines by means of the main pumps, equipped with frequency-regulated electric drive. The pipelines exploitation safety in non-stationarity conditions of pumping technological parameters can be reached by pumping regime regulation with use of frequency-regulated electric drive

Neural Adaptation at Stimulus Onset and Speed of Neural Processing as Critical Contributors to Speech Comprehension Independent of Hearing Threshold or Age

International audienceBackground: It is assumed that speech comprehension deficits in background noise are caused by age-related or acquired hearing loss.Methods: We examined young, middle-aged, and older individuals with and without hearing threshold loss using pure-tone (PT) audiometry, short-pulsed distortion-product otoacoustic emissions (pDPOAEs), auditory brainstem responses (ABRs), auditory steady-state responses (ASSRs), speech comprehension (OLSA), and syllable discrimination in quiet and noise.Results: A noticeable decline of hearing sensitivity in extended high-frequency regions and its influence on low-frequency-induced ABRs was striking. When testing for differences in OLSA thresholds normalized for PT thresholds (PTTs), marked differences in speech comprehension ability exist not only in noise, but also in quiet, and they exist throughout the whole age range investigated. Listeners with poor speech comprehension in quiet exhibited a relatively lower pDPOAE and, thus, cochlear amplifier performance independent of PTT, smaller and delayed ABRs, and lower performance in vowel-phoneme discrimination below phase-locking limits (/o/-/u/). When OLSA was tested in noise, listeners with poor speech comprehension independent of PTT had larger pDPOAEs and, thus, cochlear amplifier performance, larger ASSR amplitudes, and higher uncomfortable loudness levels, all linked with lower performance of vowel-phoneme discrimination above the phase-locking limit (/i/-/y/).Conclusions: This study indicates that listening in noise in humans has a sizable disadvantage in envelope coding when basilar-membrane compression is compromised. Clearly, and in contrast to previous assumptions, both good and poor speech comprehension can exist independently of differences in PTTs and age, a phenomenon that urgently requires improved techniques to diagnose sound processing at stimulus onset in the clinical routine

Proapoptotic activity of Ukrain is based on L. alkaloids and mediated via a mitochondrial death pathway-14

<p><b>Copyright information:</b></p><p>Taken from "Proapoptotic activity of Ukrain is based on L. alkaloids and mediated via a mitochondrial death pathway"</p><p>BMC Cancer 2006;6():14-14.</p><p>Published online 17 Jan 2006</p><p>PMCID:PMC1379651.</p><p>Copyright © 2006 Habermehl et al; licensee BioMed Central Ltd.</p>istics (white bars), measurement of mitochondrial membrane potential Δψm (grey bars) and the activation of caspase-3 (black bars) upon treatment of Jurkat Vector cells for 24 h with medium or 0, 50, 100, 150 and 250 μM allocryptopine. Data show means ± SD (n ≥ 3) (left panel). Fluorescence microscopy upon combined staining with Hoechst33342 and propidium iodide staining of cells treated with 250 μM allocryptopine for 24 h showed increased numbers of cells with apoptotic morphology upon treatment (right panel)