1,049 research outputs found

    Performance and stall limits of a YTF30-P-1 turbofan engine with uniform inlet flow

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    Performance and stall limits of YTF30-P-1 turbofan engine with uniform compressor inlet flo

    Detection of C-type natriuretic peptide (CNP) transcript in the rat heart and immune organs

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    Previous studies suggested the expression of mRNA, coding for CNP, exclusively in the central nervous system. In the present study, using the polymerase chain reaction (PCR) technique instead of the less sensitive Northern blot hybridization, CNP-specific sequences have also been detected in rat atria and ventricles of the heart as well as in organs of the immune system (thymus, spleen and lymph nodes). Parallel PCR-assays documented ANP-mRNA in these tissues. To verify specificity of the PCR-products, Southern blots have been hybridized with a third internal oligonucleotide and amplification products have been sequenced. The relative level of CNP-mRNA in these tissues was estimated to be in the range of 1-9% of total brain CNP transcripts. The results suggest that the peptide may have a peripheral as well as a central site of action. In light of its pronounced effect on cell proliferation, particular interest should focus on a possible role of CNP in the immune system

    Natriuretic peptide receptors on rat thymocytes: Inhibition of proliferation by atrial natriuretic peptide.

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    Because the thymus expresses the natriuretic peptides (NP) as well as their respective receptors, an involvement of NP in the physiology of this organ has been suggested. To evaluate functional aspects of NP in the thymus, we looked for thymic cells bearing NP receptors (Npr). Furthermore, the regulation of Npr expression by activation of cells and the influence of NP on the proliferation of thymocytes was studied. Expression of receptor messenger RNAs CmRNAs) was examined by PCR and Northern blot. Existence of functional Npr was confirmed by measurement of cGMP, the second messenger of NP. Proliferation of thymocytes upon concanavalin A (Con A) stimulation was analyzed by incorporation of [“Hlthymidine. We report here that thymocytes express mRNAs for the three Npr, namely Npra, Nprb, and Nprc and that activation of Npra and Nprb increases cGMP levels. Stimulation of thymocytes with Con A (1 pg/ml, 48 h) resulted in an increase of mRNA coding for Npra, the receptor specific for atria1 natriuretic peptide (ANP) and brain natriuretic peptide. Nprb and Nprc receptor expression was not altered under these conditions. In agreement with these data only ANP, but not the C-type natriuretic peptide, elicited increased cGMP response in Con A-stimulated cells. ANP inhibited also the proliferation of Con A stimulated thymocytes, whereas C-type natriuretic peptide did not show this effect. These results suggest that ANP affects the complex mechanisms of thymocyte proliferation and differentiation

    Different behaviour of the N-terminal and C-terminal fragment of proatrial natriuretic factor in plasma of healthy subjects as well as of patients with cirrhosis

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    N-terminal (atrial natriuretic factor (ANF) 1-98) and C-terminal (ANF 99-126) fragments of proatrial natriuretic factor (NTA and CTA, respectively) were determined in plasma of healthy subjects adopting different postures and in patients with cirrhosis. Seven healthy subjects were investigated while seated and 30 min after assuming a horizontal position. NTA plasma concentrations increased in subjects in the horizontal position (from 734±250 (SE) fmol/ml to 9021227 fmol/ml; p<0.05). In contrast, CTA plasma concentrations remained unchanged (9.2+1.3 fmol/ml vs 8.9±1.6 fmol/ml). In 10 patients with cirrhosis of the liver, NTA concentrations were markedly (p<0.001) elevated compared to 11 healthy subjects (2334±291 fmol/ml vs 743±155 fmol/ml). However, there was no difference of CTA plasma levels between cirrhotic patients and healthy subjects (8.7±1.3 fmol/ml vs 8.2±0.9 fmol/ml). These data demonstrate changes of the plasma concentration of the N-terminal fragment of proatrial natriuretic factor by posture and in liver disease, in contrast to unchanged levels of the C-terminal fragment

    StudyDB - Key Concepts

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    Our StudyDB inherits a lot of functionality from previous Django development efforts. However, StudyDB faces some additional challenges as it is intended for data collection in the context of translational human studies (empirical and prospective research, clinical trials) and »electronic« questionnaires (interfacing with and processing data from our LimeSurvey server).We would like to present our implementation of the following key concepts which might be of a more general interest and are not limited to database applications:(1) Single Source of Truth: StudyDB manages about 1000 parameters in about 30 tables. We assembled JSON files for each table describing each parameter with its data type, expected range of values and a comment including the units of measurements if applicable (all files are managed in one repository on our Github server). We use this for JSON-Schema validation, generation of test data and Python (Django) source code, online validation of input data, defining function-type fields and automatically generated documentation.(2) Timestamping as described in RFC3161 (using the “DFN Zeitstempel” service)(3) A generic table viewer optimised for object-level database access including KaTeX based LaTeX rendering

    Nuclear Factor-ÎşB-Independent Anti-Inflammatory Action of Salicylate in Human Endothelial Cells

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    In contrast to aspirin, salicylate, its active metabolite, possesses profound anti-inflammatory properties without blocking cyclooxygenase. Inhibition of the transcription factor nuclear factor-ÎşB (NF-ÎşB) has been discussed to play a role in the anti-inflammatory profile of salicylate. However, NF-ÎşB-independent effects of salicylate have been assumed but have up to now been poorly investigated. Therefore, the aim of the present study was to investigate NF-ÎşB-independent anti-inflammatory mechanisms of salicylate in human umbilical vein endothelial cells using interleukin-4 (IL-4) as NF-ÎşB-independent proinflammatory stimulus and P-selectin as inflammatory read-out parameter. Using quantitative real-time reverse transcriptionpolymerase chain reaction, we found that salicylate decreases IL-4-induced P-selectin expression. As judged by Western blot analysis, salicylate increased endothelial heme oxygenase-1 (HO-1) protein levels. Using both the HO-1 inhibitor tin(II) protoporphyrin IX and HO-1 antisense oligonucleotides, we causally linked the induction of HO-1 to the decrease of P-selectin. Moreover, we were interested in the signaling mechanisms leading to the up-regulation of HO-1 by salicylate. c-Jun NH2-terminal kinase (JNK) was found to be activated by salicylate, and we could causally link this activation to the induction of HO-1 by using the JNK inhibitor 1,9-pyrazoloanthrone. By applying activator protein-1 (AP-1) decoys, it was shown that the transcription factor AP-1 is crucially involved in the up-regulation of HO-1 downstream of JNK. In summary, our study introduces HO-1 as novel NF-ÎşB-independent anti-inflammatory target of salicylate in human endothelial cells. Moreover, we elucidated the JNK/AP-1 pathway as crucial for the induction of HO-1 by salicylate
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