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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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A transitory increase in ornithine decarboxylase (ODC) activity is shown not to be a prerequisite for the differentiation induced by hexamethylene bisacetamide (HMBA) in murine erythroleukemic (MEL) cells. On the contrary, conditions are described, where inhibition of the ODC activity with alpha-difluoromethyl ornithine (DFMO) stimulated the induced differentiation. Polyamine analysis demonstrated that a reduction in intracellular putrescine and spermidine occurred in MEL cells before commitment to erythrodifferentiation. The presence of DFMO increased the rapidity and the amplitude of these changes. No effect of dexamethasone on these changes in ODC activity or intracellular polyamines was observed. 相似文献
4.
Interaction of the serum amyloid A proteins with phospholipid 总被引:2,自引:0,他引:2
L L Bausserman P N Herbert T Forte R D Klausner K P McAdam J C Osborne M Rosseneu 《The Journal of biological chemistry》1983,258(17):10681-10688
The serum amyloid A proteins (SAA) are transported in plasma in association with the high density lipoproteins. We have studied the solution properties of two of the polymorphic forms of SAA, SAA1 and SAA4, and compared the lipid-binding properties of SAA4 to those of the well characterized apolipoproteins, apo-A-I, apo-A-II, and apo-C-III. SAA4 was monomeric at pH 2.9 but considerable self-association was demonstrated at pH 8.2, even in the presence of 1.0 M guanidine HCl. SAA4 differed from the apolipoproteins in its ability to disrupt multilamellar dimyristoylphosphatidylcholine (DMPC) liposomes and generate bilayer discs. Apo-A-I, apo-A-II, and apo-C-III reduced the turbidity of DMPC dispersions at protein:lipid molar ratios of 1:200. SAA4, however, increased turbidity at molar ratios of 1:250 and 1:100 even when preincubated in guanidine HCl before addition to liposomes. Optical density decreased only at ratios of 1:50 and 1:25. At an SAA4:DMPC ratio of 1:50, discoidal particles (long axis, 28.1 nm; short axis, 4.4 nm) were formed which were similar to those produced by apo-C-III. Lipid binding induced changes in SAA4 conformation similar to those observed in the apolipoproteins. The alpha-helical content and intrinsic tryptophanyl fluorescence were increased and quenching of tryptophanyl fluorescence by acrylamide was reduced in the presence of DMPC. In addition, SAA4 as well as the apolipoproteins broadened the range and increased the temperature of the gel-liquid crystal transition temperature of DMPC. 相似文献
5.
B A Osborne J K Lunney L Pennington D H Sachs S Rudikoff 《Journal of immunology (Baltimore, Md. : 1950)》1983,131(6):2939-2944
Miniature swine MHC antigens from three inbred herds were examined by two-dimensional gel electrophoresis. These antigens were found to constitute a series of complex glycoproteins displaying haplotype-specific patterns that allowed the distinction of both class I and class II molecules among the three haplotypes. Selected outbred pig antisera reacted with a subset of class I antigens, suggesting the presence of at least two distinct molecular species among these antigens. Similarly, alloantisera reacting with mouse Ia antigens and a monoclonal anti-human DR were shown to immunoprecipitate a subset of class II molecules. Examination of the cells from two recombinant haplotypes demonstrated that both independent recombinational events took place between the class I and class II genes. 相似文献
6.
Kinetics of histone H10 accumulation and commitment to differentiation in murine erythroleukemia cells 总被引:3,自引:0,他引:3
The accumulation of histone H10 (also denoted IP 25) in murine erythroleukemia cells, induced to differentiate with hexamethylene bis-acetamide, was shown to precede by 15-20 h the appearance in the culture of cells irreversibly committed to differentiate. In addition the rates of accumulation of H10 and of committed cells vary in a similar manner with the HMBA concentration. Flow microfluorimetric analysis demonstrated that the accumulation of H10 did not occur simultaneously in all the cells. This accumulation of histone H10 was initiated first in cell in the G2 phase of the cell cycle and subsequently in the cells situated in all the phases of the cell cycle. 相似文献
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G Terry Molinert A A Demina M Valcarcel Novo 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1986,(2):54-59
The results of the epidemiological analysis of the morbidity rate in meningococcal infection for 1976-1984 are presented. The maximum rise of morbidity rate, equal to 14.4 per 100000 of population, was observed in 1983. Primarily, the rise of morbidity rate in 1979 was induced by meningococci of two serogroups: C (44.6%) and B (36.4%). The vaccinal prophylaxis of the population, carried out in 1979 with the use of polysaccharide vaccine A + C, did not affect morbidity caused by group B meningococci. The isolation rate of these organisms reached 98.7% from patients and 81.0% from carriers. The characteristic feature of the epidemic process of meningococcal infection in Cuba was a considerable increase in the number of patients under 1 year of age and the absence of seasonal fluctuations in morbidity rate. 相似文献
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Structures of Gram-Negative Cell Walls and Their Derived Membrane Vesicles 总被引:1,自引:0,他引:1
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Terry J. Beveridge 《Journal of bacteriology》1999,181(16):4725-4733