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1.
Ernst Wm. Spannhake Terry L. Adams Steven R. Kleeberger 《Prostaglandins & other lipid mediators》1985,30(6):1041-1055
The effects of repeated antigen exposure on the synthesis of mediators by lung tissues are not well understood. To investigate the influence of antigen challenge on the synthesis of prostaglandins by central airway and peripheral lung tissues, fourteen sensitive sheep underwent biweekly exposure to aerosolized antigen (7) or saline (7). Following the fifth exposure, microsomal and high speed supernatant fractions were prepared from trachealis muscle and lung parenchyma. Synthesis of thromboxane (TX) A2, prostaglandin (PG) D2 and PGI2 from the PG endoperoxide intermediate, PGH2, was assayed over a range of substrate concentrations from 3–200 uM. Synthesis of PGI2 by trachealis microsomes was approximately 5-fold greater than that of TXA2. PGI2 and TXA2 production was identical in tracheal preparations from Ascaris- and saline-exposed animals. In parenchymal tissues, where TXA2 production predominated over PGI2 by 9-fold, preparations from Ascaris- exposed animals synthesized 50% more TXA2 than controls at PGH2 concentrations of 25 uM and above, whereas synthesis of PGI2 and PGD2 were similar in preparations from both groups of animals. The density of pulmonary mast cells was decreased by 21% in the Ascaris group, whereas polymorphonuclear leukocyte density was unchanged. These results demonstrate the differential synthesis of TXA2 and PGI2 in central airways and peripheral lung regions of the sheep. They further indicate that repeated exposure of the airways to antigen selectively enhances TXA2 synthesis in the lung periphery of sensitized animals. The site of this increased enzymatic activity, whether in resident cells or newly-infiltrated cells, has not been determined. 相似文献
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Regina M. Santella Dezider Grunberger Alfred Nordheim Alexander Rich 《Biochemical and biophysical research communications》1982,106(4):1226-1232
Poly(dG-m5dC)·poly(dG-m5dC) was modified by treatment with N-acetoxy-N-2-acetylaminofluorene (N-Aco-AAF) and its conformation examined by circular dichroism (CD) and susceptibility to S1 nuclease digestion. A sample with a modification level of 10% shows a CD spectrum characteristic of the Z form and is resistant to digestion by S1 nuclease. The relative reactivity of several polymers with N-Aco-AAF was shown to follow the order of ease of formation of Z DNA: poly(dG-m5dC)·poly(dG-m5dC) > poly(dG-dC)·poly(dG-dC) > poly(dG)·poly(dC). This suggests that AAF reacts more readily with Z DNA than B DNA. 相似文献
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The kinetics of the electrostatically induced phase transition of dimyristoyl phosphatidic acid bilayers was followed using the stopped-flow technique. The phase transition was triggered by a fast change in the pH or the magnesium ion concentration and followed by recording the time dependence of the absorbance. When the phase transition was induced by a pH jump the time course of the absorbance could be described by two exponentials, their time constants displaying the for cooperative processes characteristic maximum at the transition midpoint. The time constants are in the 10 and 100 ms range for the H+ triggered transition from the fluid to the ordered state. A third slower process shows no appreciable temperature dependence and is probably caused by vesicle aggregation. For the OH--induced transition fron the ordered to the fluid state the time constants are in the 100 and 1000 ms range. The fluid-ordered transition could also be triggered by addition of magnesium ions. Of the several observed processes only the fastest in the 10–100 ms time range could definitely be assigned to the fluid-ordered transition while the others are due to aggregation phenomena. The experimental data were compared with results obtained from pressure jump experiments and could be interpreted on the basis of theories for non-equilibrium relaxation. 相似文献
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Liane Wehder Günther Ernst Anna C. Crecelius Orlando Guntinas-Lichius Christian Melle Ulrich S. Schubert Ferdinand von Eggeling 《The journal of histochemistry and cytochemistry》2010,58(10):929-937
Carcinoma tissue consists of not only tumor cells but also fibroblasts, endothelial cells or vascular structures, and inflammatory cells forming the supportive tumor stroma. Therefore, the spatial distribution of proteins that promote growth and proliferation in these complex functional units is of high interest. Matrix-assisted laser desorption/ionization imaging mass spectrometry is a newly developed technique that generates spatially resolved profiles of protein signals directly from thin tissue sections. Surface-enhanced laser desorption/ionization mass spectrometry (MS)combined with tissue microdissection allows analysis of defined parts of the tissue with a higher sensitivity and a broader mass range. Nevertheless, both MS-based techniques have a limited spatial resolution. IHC is a technique that allows a resolution down to the subcellular level. However, the detection and measurement of a specific protein expression level is possible only by semiquantitative methods. Moreover, prior knowledge about the identity of the proteins of interest is necessary. In this study, we combined all three techniques to gain highest spatial resolution, sensitivity, and quantitative information. We used frozen tissue from head and neck tumors and chose two exemplary proteins (HNP1–3 and S100A8) to highlight the advantages and disadvantages of each technique. It could be shown that the combination of these three techniques results in congruent but also synergetic data. (J Histochem Cytochem 58:929–937, 2010) 相似文献
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N. A. Volkova N. A. Zinovieva L. A. Volkova L. K. Ernst 《Russian Journal of Genetics》2006,42(1):72-75
The data on the in vitro and in vivo (into embryonic disk) retroviral-mediated transfer of genetic information into chicken embryonic cells are presented. The estimated transformation frequency of the cultured target cells constituted 8 × 10?4 to 5 × 10?3. A transgenic rooster, carrying recombinant DNA in blood, heart, liver, and intestine cells, was obtained. 相似文献
9.
Alfred Fischel 《Development genes and evolution》1915,41(2):312-322
Ohne Zusammenfassung 相似文献
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