共查询到20条相似文献,搜索用时 125 毫秒
1.
K Jaeger M André D Scheinichen J Heine HD Kleine M Leuwer S Piepenbrock 《Canadian Metallurgical Quarterly》1997,22(5):121-124
Recovery chances for severely ill patients have been significantly improved by the progress of intensive care medicine. The success of any therapy, however, is still jeopardized by postoperative infections and septic complications. In the early stage of bacterial infections polymorphonuclear leukocytes (PMNL) play a decisive role. After PMNL activation, the production of oxygen radicals during the respiratory burst (RB) denature the phagocytosed micro-organisms. Remifentanil is a new opioid which has been safely administered to various patient groups and shows pharmacokinetic advantages in comparison to the already established opioids. As some intravenous anaesthetics can influence PMNL functions, we analysed, by flow cytometry, the in vitro influence of clinically relevant remifentanil concentrations on the respiratory burst. In our study remifentanil had no influence on the respiratory burst of human PMNL in vitro, regardless of the RB triggering agents chosen. 相似文献
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An ideal, hydrated, nondilute pseudobinary salt-protein-water solution model of the RBC intracellular solution has been developed to describe the osmotic behavior of human erythrocytes during freezing and thawing. Because of the hydration of intracellular solutes (mostly cell proteins), our analytical results predict that at least 16.65% of the isotonic cell water content will be retained within RBCs placed in hypertonic solutions. These findings are consistent not only with the experimental measurements of the amount of isotonic cell water retained within RBCs subjected to nonisotonic extracellular solutions (20-32%) but also with the experimental evidence that all of the water within RBCs is solvent water. By modeling the RBC intracellular solution as a hydrated salt-protein-water solution, no anomalous osmotic behavior is apparent. 相似文献
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以工业0.27 mm规格高磁感取向硅钢为研究对象,研究了酸溶铝(Als)含量对常化板析出物析出行为的影响.结果表明:常化板中的析岀物主要是AlN与MnS和AlN的复合析出物,随着Als含量的升高,析出物数量增加,但析出物平均尺寸变化不大.常化板中粗大的析出物大多是复合析出物,且多是以MnS为核心,AlN在MnS表面析出,而常化板中细小的析出物多为单一的析出物.常化冷却阶段,由于过饱和的Al和N在珠光体区域附近更多地析出,常化板珠光体区域附近存在较多细小的AlN粒子. 相似文献
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The granulocyte-macrophage colony stimulating factor (GM-CSF) is an important in vivo regulator of granulopoiesis and neutrophil functions. It is well-known that the immune response and the transmembrane signalling in immune cells change with aging. We wished to elucidate the effects of GM-CSF in itself and in priming the activities of other inflammatory agents on neutrophils of elderly persons. Neutrophils of 20 healthy elderly (aged 60-90 years) and 20 healthy young (aged 20-25 years) subjects were studied for superoxide anion production, intracellular free calcium mobilization, antibody dependent cellular cytotoxicity (ADCC) and intracellular killing activities. It was found that GM-CSF is unable to prime neutrophils of elderly subjects to the action of FMLP, metenkephalin or opsonized zymosan. By the use of Pertussis toxin and H7 it was demonstrated that a different signal transduction pathway in neutrophils of elderly subjects is activated by GM-CSF or FMLP if compared to that of young subjects. These results suggest that the lack of priming could contribute to the greater susceptibility of the elderly to infections and that the change of the signal transduction mechanism in neutrophils of elderly subjects might partly explain this phenomenon. 相似文献
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Since 1996, the curriculum "Quality management for physicians" exists with a three-level training concept. Based on these contents, a purposeful course program has been developed by the ZQ, and through May 1998 four level I-, four level II- and four level III-courses have been performed in Hannover. Thus, 50 physicians are qualified for new professional roles as hospital quality managers. The evaluation of a standardized questionnaire shows that the concept is highly accepted--meanwhile also by other professionals in health care. As a new model of quality assurance/quality evaluation is now developed for German hospitals, the contents of the training program will be updated for actual needs. 相似文献
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摘 要:为了掌握Als(酸溶铝)和Nb含量对取向硅钢中夹杂物特征的影响,借助场发射扫描电镜(FE-SEM)结合能谱仪(EDS)和图像分析软件研究了钢中夹杂物类型、数量、尺寸及尺寸分布,结合钢液凝固过程中溶质元素的微观偏析模型,重点分析了Als和Nb含量影响钢中AlN和NbN析出的机制。结果表明,钢中的夹杂物以NbN、AlN和AlN-NbN为主,夹杂物尺寸分布由Als和Nb含量综合影响。Als含量的增加使含氧复合夹杂物中Al2O3含量增加,SiO2含量降低,促进了钢中硅酸盐类氧化物夹杂的去除,但大大增加了AlN和AlN-NbN夹杂的偏析析出。Nb含量的增加使夹杂物的平均尺寸变小,促进了钢中NbN在凝固前沿的提前析出和以氧化物为核心析出。Als主要影响钢中的氧化物和氮化物夹杂,Nb通过影响与Als结合的O和N的活度影响钢中氧化物和氮化物夹杂的析出特性。 相似文献
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In order to elucidate the effect of Als (acid soluble aluminum) and Nb content on the characteristics of inclusions in grain oriented silicon steel, the type, quantity, size and size distribution of inclusions were studied by the field emission scanning electron microscope (FE SEM) equipped with an energy dispersive X ray spectroscopy (EDS) and image analysis software. Combined with the micro segregation model of solute elements during solidification, the precipitation mechanism of AlN and NbN inclusions was analyzed specially. The results indicate that the inclusions are mainly NbN, AlN and AlN-NbN, and the size distribution of the inclusions is affected by Als and Nb simultaneously. With the increase of Als content added in the steel, the content of Al2O3 in the oxide composite inclusions increases, while that of SiO2 decreases. The increase of Als content promotes the removal of silicate inclusions in the steels, but the segregation precipitation of AlN and AlN NbN inclusions increases. With the increase of Nb content added in the steel, the average size of inclusions reduces. The increase of Nb content promotes the earlier precipitation of NbN at the solidification front and its precipitation with oxides as the core. Als mainly affects the precipitation characteristics of oxide and nitride inclusions in the steel, and Nb also affects the oxides and nitrides precipitation characteristics via affecting the activity of oxygen and nitrogen combined with Als. 相似文献
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Role of calcium in the shape control of human granulocytes 总被引:1,自引:0,他引:1
Y Zaffran H Lepidi AM Benoliel C Capo P Bongrand 《Canadian Metallurgical Quarterly》1993,19(1):115-29; discussion 129-31
The possible role of cytoplasmic calcium in the shape control of human blood granulocytes was explored with two complementary sets of experiments. First, cells were stimulated with N-formyl methionyl leucyl phenylalanine (FMLP) with or without depletion of free intracellular calcium (by incubation with BAPTA/AM in calcium-deprived medium). Control cells displayed a rapid and transient rise of free intracellular calcium (peaked after a few seconds, returned to the basal level after 2-3 minutes), extensive morphological polarization (more than 90% polarized cells after 15 minutes), and reorganization of actin filaments (as assessed by image analysis on cells labeled with a fluorescent phallacidin derivative). Calcium-depleted cells displayed no calcium rise, but both morphological polarization and actin reorganization were indistinguishable from those of controls. In a second set of experiments, individual granulocytes were labeled with fluorescent calcium probes and aspirated in a micropipette on the stage of a confocal laser microscope. About half of the cells displayed a transient calcium rise, which was concomitant with the formation of a protrusion in most cases. However, extensive protrusions were shown by the cells that did not exhibit calcium flashes. Furthermore, if cells were treated with ionomycin, in calcium-containing or calcium-deprived medium, then aspirated, they showed protrusions comparable to those of controls. Finally, when cells were treated with ionomycin during micropipette aspiration, a calcium rise was followed by a moderate increase of the rate of protrusion growth. It is concluded that free calcium alone cannot play a major role in the control of cell shape. 相似文献
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L-selectin and Mac-1 expressed on leukocytes are critical for leukocyte adhesion to inflamed endothelium. L-selectin is known to be rapidly shed from the cell surface of granulocytes after activation. In the present study the change of expressions of these adhesion molecules on granulocytes were analyzed by flow cytometry, and the serum concentration of shed L-selectin (soluble L-selectin; sL-selectin) was measured by enzyme-linked immunosorbent assay (ELISA) during hemodialysis in patients treated with regenerated cellulose membranes (RC group) versus polysulfone membranes (PS group). In the RC group, Mac-1 expression on granulocytes increased significantly at 30 min after the initiation of hemodialysis (p < 0.05) compared with predialysis values, coinciding with the nadir of dialysis-induced granulocytopenia. Granulocyte L-selectin expression decreased significantly at 15 min after the initiation of hemodialysis (p < 0.05) and remained decreased through the course of dialysis session, compared with predialysis values. Serum sL-selectin level significantly increased at 15 min after the initiation of hemodialysis (p < 0.05), compared with predialysis values. In the PS group, no significant variation in Mac-1 and L-selectin expression on granulocytes and serum sL-selectin level were detected. This reciprocal change of Mac-1 and L-selectin on granulocyte cell surface was attributed to development of granulocytopenia and subsequent reversal during dialysis with cellulose membranes. In this study, we confirmed the shedding of L-selectin during cellulosic dialysis by ELISA. The increase in sL-selectin, which has potential activity of inhibiting L-selectin-dependent adhesion of granulocyte to endothelium, might be involved in rebound granulocytosis during dialysis with cellulose membranes and impairment of the granulocyte function in patients on chronic hemodialysis. 相似文献
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The effect of the XeCl-308nm excimer laser on the mineral content and surface morphology of cut dentin was examined in ten extracted human teeth. Each dentin specimen was lased for 4 s at a fluence of 1 J/cm2 and a frequency of 25 Hz. Non-lased area of the same specimen served as control. Scanning electron microscopy and energy dispersive spectrometry revealed a significant decrease in the phosphorus levels following laser treatment. A decrease in calcium levels also occurred but was not statistically significant. Nonsignificant changes in sulphur and potassium levels were also noted. Morphologically, the lased dentin showed an apparently melted surface with partial obstruction of the dentin tubules as well as cracks along the lased surface. Therefore, it appeared that laser treatment may alter the chemical structure as well as the surface morphology of the dentin. 相似文献
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Al. G. Shalimov 《Steel in Translation》2011,41(11):938-946
Factors that affect the behavior of nitrogen in electrosmelting, ladle treatment, and continuous casting of steel are considered. The possibility of obtaining a low nitrogen content in electrosteel is investigated in terms of the purity of the oxygen employed and the nitrogen content in the batch and in the materials used for smelting and ladle treatment. Specific recommendations are made for reduction in the nitrogen content. 相似文献
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D Hoffmann 《Canadian Metallurgical Quarterly》1976,282(10):1021-1024
Last instar larvae of Locusta migratoria can be protected ("vaccinated") against lethal doses of Bacillus thuringiensis by previous injections of low doses of this pathogen. If iron saccharate is injected in to larvae prior to the administration of the "vaccinating" dose of Bacillus thuringiensis, no antibacterial protection can be induced. Injection of iron saccharate in to "vaccinated" larvae does not interfere with the induced protection; such larvae resist lethal doses. 相似文献
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Y Kurata I Hisatome M Tsuboi H Uenishi G Zhang M Oyaizu R Sato S Imanishi 《Canadian Metallurgical Quarterly》1998,63(12):1023-1035
Effects of sulfhydryl oxidizing and reducing agents on permeability of the tetrodotoxin (TTX)-insensitive Na-channel were investigated in guinea-pig ventricular myocytes using the whole-cell patch-clamp technique. Mercury chloride (HgCl2) at 1-100 microM irreversibly blocked Na+ currents with no significant changes in the gating kinetics. In contrast, the hydrophilic sulfhydryl oxidizing agent, thimerosal at 50-100 microM little affected Na+ permeation through the Na-channel. The Hg2+-induced block of Na+ current could be readily reversed by 1,4-dithiothreitol (DTT), an agent that reduces disulfide bonds. These results indicate that the formation of sulfur-Hg-sulfur bridge is essential for Hg2+ block. Pretreatment with DTT prevented the Hg2+ block of Na+ current, whereas Zn2+ and Cd2+ retained their abilities to block Na+ current after DTT treatment. An application of Zn2+ or Cd2+ resulted in the restoration of Hg2+ sensitivity of the DTT-treated channel. A conformational model for the Na-channel with multiple free sulfhydryl groups and native disulfide bonds could account for our experimental data regarding the effects of sulfhydryl modifying agents on the channel permeability. We conclude that the cardiac TTX-insensitive Na-channel contains functionally important free sulfhydryl groups and disulfide bonds which are accessible from the extracellular side by an aqueous pathway. These sulfhydryls would be capable of modulating the Na-channel permeability by affecting the conformation of channel pore region. 相似文献
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PH Nibbering B Thio AC Bezemer RL Beijersbergen TP Zomerdijk 《Canadian Metallurgical Quarterly》1997,137(1):65-75
Basal and stress levels of catecholamines (CA) in the adrenal glands, and circulatory levels of adrenocorticotropic hormone (ACTH) were examined in female Wistar rats aged 1, 3, 10 and 24 months. Our data showed reduction in basal dopamine (DA) concentration in adrenal glands and an increase in this catecholamine in response to stress at all ages (1, 3, 10, 24 months). The greatest levels of basal norepinephrine (NE) and epinephrine (E) concentrations in the adrenal glands were noted in intact rats at the age of 24 months. On the other hand, the stress response of NE and DA had a tendency to fall, reaching basal values at the age of 10 and 24 months of age. Basal circulatory levels of ACTH showed a reduction with age. The stress response of ACTH was reduced in animals aged 10 and 24 months. Reduced basal values of adrenal DA and increased NE and E values, suggest that there is increased adrenomedullar activity at the age of 24 months. On the other hand, the reduced or even absent stress response of NE and E observed in the adrenals, in 10 and 24 months old rats, may be of interest in considering the ability of these animals for adaptation. Basal and stress values of plasma ACTH are significantly reduced with the onset of senescence in female rats. 相似文献
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The effect of hydrocortisone on the phagocytosis and intracellular killing by mouse peritoneal macrophages in vitro was studied by a method making it possible to measure these processes separately. The results showed that in vivo treatment with 15 mg of hydrocortisone acetate did not significantly decrease the phagocytosis of several bacterial species such as Staphylococcus albus, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Pseudomonas aeruginosa. The killing indexes of normal macrophages for the various microorganisms were found to be significantly different. This may indicate that the bactericidal mechanisms are not uniform for these bacteria. The effect of hydrocortisone on the intracellular killing was also variable. For Staphylococcus albus a normal killing index was found. For the other species of bacterial and for Candida albicans some decrease was found, but this was only significant for Salmonella typhimurium. It is concluded that a decrease host resistance due to glucocorticosterioid treatment is not caused by a direct effect of these drugs on the phagocytosis and intracellular killing by mononuclear phagocytes. 相似文献
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The sequence proline-proline-glycine-proline is highly conserved in cytochrome P450 families 1 and 2, and similar proline rich sequences are found in other cytochromes P450. Since this sequence immediately follows the NH2-terminal hydrophobic membrane insertion signal, it potentially could function as a signal either for retention of cytochrome P450 in the endoplasmic reticulum or for its correct orientation in the membrane. To test this possibility, DNA sequence coding for this tetrapeptide was deleted from cytochrome P450 2C2 cDNA. Translation of the mutated mRNA in a reticulocyte cell-free system containing canine microsomal membranes resulted in the insertion of the protein into the membrane with a topology indistinguishable from that of normal cytochrome P450 2C2. The mutated protein was expressed in COS1 cells and its distribution, assayed by immunofluorescence, was similar to that of cytochrome P450 2C2. Furthermore, if a short peptide containing a potential glycosylation site was fused to the N-terminus of the mutant protein, the new hybrid protein was glycosylated in COS1 cells and the carbohydrate moiety remained sensitive to cleavage by endoglycosidase H. These results indicate that the protein was inserted and retained in the endoplasmic reticulum membrane. Pulse-chase studies showed that the mutated protein was degraded about four times as fast as cytochrome P450 2C2. In contrast to cytochrome P450 2C2, no (omega-1) hydroxylase activity was detected in COS1 cells expressing the mutated protein at similar steady-state levels as the wild-type protein. These results indicate that, although the conserved PPGP tetrapeptide is not required for cellular localization of cytochrome P450 in the endoplasmic reticulum membrane, its deletion decreases the stability of the protein and abolishes enzymatic activity. 相似文献
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A projective battery was administered to 22 graduate theological students. One group received the Rorschach first followed by the TAT and the DAP. The other group was administered 9 TAT cards and 2 DAP drawings first after which they took the Rorschach. Both groups were matched on the variables of sex, age, IQ, R, and examiner. The group receiving the Rorschach last produced significantly more human content than the group receiving the Rorschach 1st. These findings, if independently confirmed, would indicate that, although previously overlooked, test order may be an important factor in modifying certain projective test scores. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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