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61.
Secretion in neutrophils is thought to be regulated in different ways for the different granule types. Specific granules are endowed with proteins which are related to docking and fusion events and are absent on azurophilic granules. Furthermore, even if secretion of content from all neutrophil granules is a Ca(2+)-dependent process, a higher concentration of cytosolic calcium is required for azurophilic than for specific granule secretion. In this paper we show that human neutrophils and promyelocitic cells express neuronal calcium sensor-1 (NCS-1), a calcium binding protein involved in exocytosis in various cell types. Both mRNA and protein were found in mature cells and precursors. NCS-1 is shown to be mainly associated with azurophilic granules and, therefore could play an instrumental role in the calcium-dependent secretion of azurophilic granules.  相似文献   
62.
Cell adhesion and migration are important features in tumor invasion, being mediated in part by integrins (extracellular matrix receptors). Integrins are significantly decreased in human prostate cancer. An exception is 6 integrin (laminin receptor) which persists during prostate tumor progression. We have selected high (DU-H) and low (DU-L) expressors of 6 integrin from a human prostate tumor cell line, DU145, to assess experimentally the importance of 6 integrin in tumor invasion. DU-H cells exhibited a four-fold increased expression of 6 integrin on the surface compared to DU-L cells. Both cell types contained similar amounts of 3 and 5 integrin. The DU-H cells contained 6 subunits complexed with both the 1 and 4 subunits whereas DU-L cells contained 6 complexed only with 4. DU-H cells were three times more mobile on laminin as compared to DU-L, but adhered similarly on laminin. Adhesion and migration were inhibited with anti-6 antibody. Each subline was injected intraperitoneally into SCID mice to test its invasive potential. Results showed greater invasion of DU-H compared to DU-L cells, with increased expression of a6 integrin on the tumor at the areas of invasion. These data suggest that 6 integrin expression is advantageous for prostate tumor cell invasion.  相似文献   
63.
The proximal region of the superficial digital flexor tendon of pigs passes under the tibiotarsal joint, where it is subjected to compressional and tensional forces. This region was divided into a surface portion (sp), which is in direct contact with the bone and into a deep portion (dp), which is the layer opposite the articulating surface. The purpose of this work was to analyse the distribution and organisation of the collagen bundles and proteoglycans in the extracellular matrix in sp and dp. Toluidine‐blue‐stained sections were analysed under a polarising microscope. Strong basophilia and metachromasia were observed in sp, demonstrating accumulation of proteoglycan in a region bearing compression, but the intensity was reduced the further layers were from the bone. Linear dichroism confirmed that the glycosaminoglycan molecules were disposed predominantly parallel to the longest axis of the collagen fibrils. Birefringence analysis showed a higher molecular order and aggregation of the collagen bundles in areas where the tension was more prominent. The crimp pattern was more regular in dp than in sp, probably as a requirement for tendon stretching. The optical anisotropy exhibited by the collagen bundles also confirmed the helical organisation of the collagen bundles in the tendon. Hyaluronidase digestion caused a decrease in the basophilia, but this was not eliminated, supporting the idea that in the matrix, proteoglycans are not completely available to the enzyme action.  相似文献   
64.
Allicin, the main organic allyl sulfur component in garlic, exhibits immune-stimulatory and antitumor properties. Allicin stimulated [(3)H]thymidine incorporation in mouse splenocytes and enhanced cell-mediated cytotoxicity in human peripheral mononuclear cells. Multiple administration (i.p.) of allicin elicited a marked antitumor effect in mice inoculated with B-16 melanoma and MCA-105 fibrosarcoma. The immune-stimulatory and antitumor effects of allicin are characterized by a bell-shaped curve, i.e. allicin at high, supra-optimal concentrations is less effective or inhibitory. Allicin induced activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in human peripheral mononuclear cells, and also in wild-type Jurkat T-cells. Allicin failed to activate ERK1/2 in Jurkat T cells that express p21(ras), in which Cys118 was replaced by Ser. These cells are not susceptible to redox-stress modification and activation. We postulate that the immune stimulatory effect of allicin is mediated by redox-sensitive signaling such as activation of p21(ras). It is suggested that the antitumor effect of allicin is related to its immune-stimulatory properties.  相似文献   
65.
为了研究细胞外信号调节激酶(ERK)信号转导通路在三叉神经痛动物模型中的表达,将24只雄性SD大鼠分为三叉神经痛模型组和对照组两组,模型组大鼠以铬制羊肠线疏松结扎大鼠一侧眶下神经,对照组大鼠眶下神经不结扎。应用免疫组化和免疫荧光染色方法,分别检测大鼠三叉神经节(TG)和三叉神经脊束核尾侧亚核(Vc)中磷酸化ERK(p-ERK)的表达。本研究发现p-ERK在模型组和对照组大鼠的TG和Vc中均有不同程度的表达,但模型组大鼠中p-ERK表达明显高于对照组(P<0.05)。提示ERK可能参与了三叉神经痛(TGN)痛觉信号的传导,在三叉神经痛的发病机制中发挥重要的作用。  相似文献   
66.
Human defensins   总被引:7,自引:0,他引:7  
Antimicrobial peptides are small, cationic, amphiphilic peptides of 12–50 amino acids with microbicidal activity against both bacteria and fungi. The eukaryotic antimicrobial peptides may be divided into four distinct groups according to their structural features: cysteine-free -helices, extended cysteine-free -helices with a predominance of one or two amino acids, loop structures with one intramolecular disulfide bond, and -sheet structures which are stabilised by two or three intramolecular disulfide bonds. Mammalian defensins are part of the last-mentioned group. The mammalian defensins can be subdivided into three main classes according to their structural differences: the -defensins, -defensins and the recently described -defensins. Mammalian -defensins are predominantly found in neutrophils and in small intestinal Paneth cells, whereas mammalian -defensins have been isolated from both leukocytes and epithelial cells. Recently, two novel human -defensins, human beta-defensin-3 (HBD-3), and human beta-defensin-4 (HBD-4) have been discovered. Similar to HBD-1 and HBD-2, HBD-3 has microbicidal activity towards the Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli) and the yeasts Candida albicans and Malassezia furfur. In addition, HBD-3 kills Gram-positive bacteria such as Streptococcus pyogenes or Staphylococcus aureus, including multi-resistant S. aureus strains, and even vancomycin-resistant Enterococcus faecium. In contrast to HBD-1 and HBD-2, significant expression of HBD-3 has been demonstrated in non-epithelial tissues, such as leukocytes, heart and skeletal muscle. HBD-4 is expressed in certain epithelia and in neutrophils. Its bactericidal activity against P. aeruginosa is stronger than that of the other known -defensins. Here we present an overview of human antimicrobial peptides with some emphasis on their antifungal properties.J.J. Schneider and A. Unholzer contributed equally to this work  相似文献   
67.
Transmission electron microscopy of thin sections of the rat incisor pulp revealed that in the middle region of the incisor there were fenestrated capillaries in the “predentinal plexus” and that this region contained the tallest odontoblasts. The odontoblasts gradually became shortened in the incisal part of this region: the fenestrated capillaries in the predentinal plexus changed to continuous type capillaries. Almost all the odontoblasts had degenerated near the incisal end of the tooth. The predentinal plexus disappeared in this region, but the “subodontoblastic capillary plexus” persisted. In a specific region just beneath the worn incisal end, numerous macrophages and polymorphonuclear neutrophils appeared and scavenged the degenerating cells, possibly including the odontoblasts. © 1993 Wiley-Liss, Inc.  相似文献   
68.
目的:探讨高糖对体外培养Schwann细胞生长及细胞外信号调节激酶(ERK)磷酸化的影响.方法:按照培养液中葡萄糖浓度的小同,分为对照组与高糖组.用MTT法检测Schwann细胞生长情况;用ELISA法检测对照组与高糖组ERK1/2磷酸化的程度,以及加入神经源性一氧化氮合成酶(nNOS)抑制剂后ERK1/2磷酸化的程度.结果:高糖浓度下,细胞虽有增殖但幅度及时程明显低于对照组,高糖抑制Schwann细胞生长;随着精浓度的升高.ERK1/2磷酸化的程度逐渐增加,并与加入nNOS抑制剂有相似的表现.结论:高糖抑制Schwann细胞生长,并且降低nNOS的量,减弱一氧化氮(NO)对ERK1/2的抑制作用,导致ERK1/2磷酸化水平升高.  相似文献   
69.
BACKGROUND: First trimester increased fetal nuchal translucency is associated with fetal aneuploidies. One of the mechanisms of pathophysiology could be an abnormal extracellular matrix facilitating the formation of an interstitial edema. A previous study investigating interstitial edema in first trimester fetuses found large amounts of hyaluronan in the skin of fetuses with trisomy 21. The aim of this study was to establish distribution patterns for a number of other glycosaminoglycans-dermatan, heparan and keratan sulphate, chondroitin-6-sulphate and chondroitin-4-sulphate proteoglycan-in the nuchal skin of normal and chromosomally abnormal fetuses at 11-14 weeks. We also investigated whether biglycan (BGN), which is located on chromosome X, is underexpressed in fetuses with Turner syndrome. Decorin (DCN), a similar-sized proteoglycan located on chromosome 12, was taken as a control. METHODS: We studied the distribution and concentration of various extacellular matrix components using immunohistochemistry, a double staining technique, in-situ hybridization, Northern and Western blot analysis. RESULTS: Chondroitin-6-sulphate and chondroitin-4-sulphate proteoglycan were increased in Turner syndrome fetuses and BGN seemed to be underexpressed compared with normal controls, while DCN was not. Dermatan, heparan and keratan sulphate showed no significant abnormal distribution in trisomies 21, 18, 13, or in Turner syndrome, compared with normal. Western and immunohistochemical analysis revealed that absence of a second X chromosome, as is the case in Turner syndrome, affects BGN protein pattern. CONCLUSIONS: An abnormal amount of glycosaminoglycans and proteoglycans presumably contributes to increased nuchal translucency.  相似文献   
70.
The relationship between autoantibody reactivities and nephritis in systemic lupus erythematosus (SLE) is unclear. We studied MRL/l mice which developed a considerable albuminuria (either mice with short (< 1 week) or heavy and prolonged (3 weeks) albuminuria) and compared them with non-albuminuric age-matched controls, with young (12 weeks old) non-albuminuric mice and with mice which were followed for 36 weeks and did not develop albuminuria. In a longitudinal prospective study on plasma samples we correlated a variety of anti-nuclear reactivities and reactivities against extracellular matrix (ECM) components, with the onset of albuminuria. We found that at the onset of albuminuria, anti-DNA was higher while anti-nucleosome and anti-H2A/H2B-DNA subnucleosome reactivities were lower compared with age-matched non-albuminuric mice. We also studied glomerular eluates of these mice in ELISA and in indirect immunofluorescence (IF). In the eluates we found with IF that anti-glomerular basement membrane (GBM)-tubular basement membrane (TBM) antibodies were already present in 12-week-old non-albuminuric mice. These eluates showed no anti-nuclear antibodies. In eluates of albuminuric mice more immunoglobulin was deposited, and anti-ECM, anti-DNA and anti-nucleosome reactivities were higher than in eluates of age-matched non-albuminuric mice. The deposition of anti-nucleosome antibodies preceded the deposition of anti-DNA antibodies since they were deposited to a greater extent in mice with a short albuminuria. We conclude that anti-GBM-TBM antibodies are the first autoantibodies that deposit in glomeruli of MRL/l mice at an early age. The onset of albuminuria is associated with additional deposition of both anti-ECM and anti-nuclear (anti-nucleosome and anti-DNA) antibodies, but the difference with non-albuminuric mice seems to be more quantitative than qualitative.  相似文献   
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