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41.
Cytokineplasts (CKP) are anucleate, motile, granule-poor fragments induced from polymorphonuclear leukocytes on surfaces by the brief application of heat. Derived from the peripheral cytoplasm and membranes of PMN, they retain the sensing, transducing, and effector mechanisms necessary for chemotaxis and phagocytosis, and appear to represent a functional, self-purification of the motile apparatus. Unlike their parent PMN, CKP are cryopreservable. We have shown that they can adhere to endothelial cell monolayers, open interendothelial cell junctions, and migrate to the abluminal side when stimulated by a chemoattractant. Employing an animal model, we now show that, given intravenously, they can home to an inflammatory target lesion in vivo. 相似文献
42.
Dana W. Dunne Albert Shaw Linda K. Bockenstedt Heather G. Allore Shu Chen Stephen E. Malawista Lin Leng Yuka Mizue Marta Piecychna Lin Zhang Virginia Towle Richard Bucala Ruth R. Montgomery Erol Fikrig 《PloS one》2010,5(6)
Background
An increasing number of patients have medical conditions with altered host immunity or that require immunosuppressive medications. While immunosuppression is associated with increased risk of infection, the precise effect of immunosuppression on innate immunity is not well understood. We studied monocyte Toll-like receptor (TLR) expression and cytokine production in 137 patients with autoimmune diseases who were maintained on immunosuppressive medications and 419 non-immunosuppressed individuals.Methodology/Principal Findings
Human peripheral blood monocytes were assessed for surface expression of TLRs 1, 2, and 4. After incubation with TLR agonists, in vitro production of the cytokines IL-8, TNFα, and MIF were measured by ELISA as a measure of TLR signaling efficiency and downstream effector responsiveness. Immunosuppressed patients had significantly higher TLR4 surface expression when compared to non-immunosuppressed adults (TLR4 %-positive 70.12±2.28 vs. 61.72±2.05, p = 0.0008). IL-8 and TNF-α baseline levels did not differ, but were significantly higher in the autoimmune disease group following TLR stimulation. By contrast, baseline MIF levels were elevated in monocytes from immunosuppressed individuals. By multivariable analyses, IL-8 and TNFα, but not MIF levels, were associated with the diagnosis of an underlying autoimmune disease. However, only MIF levels were significantly associated with the use of immunosuppressive medications.Conclusions/Significance
Our results reveal that an enhanced innate immune response is a feature of patients with autoimmune diseases treated with immunosuppressive agents. The increased risk for infection evident in this patient group may reflect a dysregulation rather than a simple suppression of innate immunity. 相似文献43.
添加玉米和水稻秸秆对淹水土壤pH、二氧化碳及交换态铵的影响 总被引:4,自引:0,他引:4
通过温室土壤培养试验,研究了不同添加量玉米和水稻秸秆对淹水土壤pH、CO2及交换态铵的影响.结果表明:在接近中性的土壤中加入秸秆可使土壤pH值降低,4 g·kg-1玉米和水稻秸秆处理的土壤pH值均与对照差异显著(P<0.05),而1 g·kg-1玉米和水稻秸秆处理与对照差异不显著(P>0.05).土壤溶液中的CO2含量随秸秆添加量的增加而增大,1 g·kg-1玉米和水稻秸秆处理的土壤溶液CO2含量最大值分别为35.9%和31.9%(v/v),与对照(25.8%)差异达显著水平(P<0.05),但两者间差异不显著(P>0.05);4 g·kg-1玉米和水稻秸秆处理的土壤溶液CO2含量最大值分别为54.2%和41.8%(v/v),与对照差异极显著(P<0.01),两者间差异也达显著水平(P<0.05).在不施氮肥的情况下,添加秸秆可降低土壤铵态氮浓度,且铵态氮浓度随秸秆添加量的增加而降低,不同添加量处理间差异显著(P<0.05);在施入氮肥的情况下,1 g·kg-1玉米和水稻秸秆处理提高了土壤铵态氮浓度,而4 g·kg-1玉米和水稻秸秆处理降低了土壤铵态氮浓度.无论是否施入氮肥,玉米和水稻秸秆处理的土壤铵态氮浓度差异不显著(P>0.05). 相似文献
44.
MARIA-MARCELA POVEDA MARIE-CLAUDE SOUQUAL MARIE-THÉRÈSE FAUVEL JACQUES GAMISANS THIERRY GAUQUELIN 《Botanical journal of the Linnean Society. Linnean Society of London》2002,140(2):165-168
The cuticular wax composition of leaves has been analysed in three western European populations (Corsica, central Pyrenees, northern Alps) of Juniperus communis var. saxatilis Pall. (= J. nana Willd., nom illeg.) and in one population of J. communis L. var. depressa Pursh. from North America (Sierra Nevada). Gas chromatography shows the presence of 13 alkanes in all samples ranging from C23 to C35 with important intraspecific polymorphism in alkane content. The dominant alkanes range from C33 to C35 . Alkanes C21 and C22 were found only in Corsica and Sierra Nevada populations. Canonical discriminant analysis separated the J. communis L. var. depressa Pursh. of the population of Sierra Nevada from other populations of J. communis var. saxatilis Pall. on the basis of their higher C31 content and the constant presence of C21 and C22 alkanes. J. communis var. saxatilis Pall. populations from the Pyrenees are close to northern Alps populations characterized by high concentrations of C33 , C34 and C35 alkanes. This paper confirms the existence of Juniperus var. saxatilis Pall. in the Pyrenees (France). © The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 165–168. 相似文献
45.
SE?Aleshin AV?Timofeev MV?Khoretonenko LG?Zakharova GV?Pashvykina JR?Stephenson AM?Shneider AD?AltsteinEmail author 《BMC microbiology》2005,5(1):45
Background
Heterologous prime-boost immunization protocols using different gene expression systems have proven to be successful tools in protecting against various diseases in experimental animal models. The main reason for using this approach is to exploit the ability of expression cassettes to prime or boost the immune system in different ways during vaccination procedures. The purpose of the project was to study the ability of recombinant vaccinia virus (VV) and bacterial plasmid, both carrying the NS1 gene from tick-borne encephalitis (TBE) virus under the control of different promoters, to protect mice against lethal challenge using a heterologous prime-boost vaccination protocol. 相似文献46.
Kaplow LS Chevance Ad Ade B Henkel J Malawista SE 《Cell motility and the cytoskeleton》2002,53(4):289-292
The study was carried out under direct videomicroscopic control to ascertain whether electromagnetic forces (photons) can initiate directed cell motility of human polymorphonuclear neutrophils (PMN). Cell suspensions containing a mixture of randomly motile white blood cells and erythrocytes (red cells) were placed in a double-decked preparation created by a glass slide and two cover slips and sealed by paraffin. Erythrocytes in the upper or lower chamber were destroyed by a single burst from a narrow ruby laser beam. Directed locomotion of PMN toward the erythrocyte debris occurred exclusively in the chamber in which the erythrocytes had been destroyed. Only random PMN locomotion was observed in the adjacent chamber. The results indicate that in this experimental model, electromagnetic forces do not initiate directed locomotion. 相似文献
47.
People can eat a food without having a strong preference for it, and people can prefer a food without eating it. Given this seeming disconnect between attitude and behavior, which type of measure or segment can best be used to profile or identify loyal consumer segments of a food, such as soy? This research compares a usage‐based method (heavy‐light‐nonusers) with a new attitude‐based method (seeker‐neutral‐avoider), and finds that the attitude‐based method differentiates purchase‐related intentions better than the usage‐based method. Implications for profiling consumer taste patterns and consumer segments are provided. 相似文献
48.
Ustilago maydis, the causal agent of corn smut disease, displays dimorphic growth in which it alternates between a unicellular, nonpathogenic yeast-like form and a dikaryotic, pathogenic filamentous form. Previously, a constitutively filamentous haploid mutant was obtained. Complementation of this mutant led to the isolation of the gene encoding adenylate cyclase, uac1. Secondary mutagenesis of a uac1 disruption strain allowed the isolation of a large number of suppressor mutants, termed ubc, for Ustilago bypass of cyclase, lacking the filamentous phenotype. Analysis of one of these suppressor mutants previously led to the identification of the ubc1 gene, encoding the regulatory subunit of cAMP-dependent protein kinase. In this report we describe the isolation of cosmids containing three new ubc genes, termed ubc2, ubc3, and ubc4. We also describe the morphology of the ubc2, ubc3, and ubc4 mutants in a uac1- background as well as in a background with a functional uac1 gene. In addition, we describe several mutant strains not complemented with any of the genes currently in hand and that are thus presumed to possess mutations in additional ubc genes. Copyright 1998 Academic Press. 相似文献
49.
Variation in rates of molecular evolution now appears to be widespread. The
demonstration that body size is correlated with rates of molecular
evolution suggests that physiological and ecological factors may be
involved in molecular rate variation, but large-scale comparative studies
are still lacking. Here, we use complete cytochrome b sequences from 85
species of tube-nosed seabirds (order Procellariiformes) and 5 outgroup
species of penguins (order Sphenisciformes) to test for an association
between body mass and rates of molecular evolution within the former avian
order. Cladistic analysis of the 90 sequences estimates a phylogeny largely
consistent with the traditional taxonomy of the Procellariiformes. The
Diomedeidae, Procellariidae, and Pelecanoididae are monophyletic, while the
Hydrobatidae are basal and paraphyletic. However, the two subfamilies
within the Hydrobatidae (Hydrobatinae and Oceanitinae) are monophyletic. A
likelihood ratio test detects significant deviation from clocklike
evolution in our data. Using a sign test for an association between body
mass and branch length in the seabird phylogeny, we find that larger taxa
tend to have shorter terminal branch lengths than smaller taxa. This
observation suggests that rates of mitochondrial DNA evolution are slower
for larger taxa. Rate calibrations based on the fossil record reveal
concordant body size effects. We interpret these results as evidence for a
metabolic rate effect, as the species in this order exhibit large
differences in metabolic rates, which are known to be highly correlated
with body mass in this group. Our results support previous findings of body
size effects and show that this effect can be significant even within a
single avian order. This suggests that even lineage-specific molecular
clocks may not be tenable if calibrations involve taxa with different
metabolic rates.
相似文献
50.
THE MOBILIZATION AND EXTRACELLULAR RELEASE OF GRANULAR ENZYMES FROM HUMAN LEUKOCYTES DURING PHAGOCYTOSIS 总被引:22,自引:5,他引:17
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The importance of granular (lysosomal) enzymes from neutrophils in producing the tissue damage of acute inflammation has been suggested by much indirect and some direct evidence. This study has investigated the kinetics of release and subsequent fate of granular enzymes from phagocytizing human leukocytes The following observations are made: (a) During phagocytosis, the granular enzyme lysozyme is released from leukocytes into the extracellular medium. (b) Release of lysozyme increases as phagocytic challenge increases, but attains a maximum. (c) Release of lysozyme accompanies phagocytosis and is not a delayed event. (d) The lack of release of a nongranular enzyme, lactic dehydrogenase, indicates that cell damage is not a necessary condition of enzyme release. (e) Like lysozyme, β-glucuronidase is released from phagocytizing leukocytes. Acid α-naphthyl phosphatase and cathepsin also appear to be released, but are not found in appreciable amounts in the extracellular medium, in part because of their lability in solution. These results support the concept that extracellular release of granular enzymes may be a useful secretory function of inflammatory leukocytes which becomes damaging to the host in certain circumstances. 相似文献