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排序方式: 共有236条查询结果,搜索用时 15 毫秒
11.
Plasminogen activator inhibitor-1 and vitronectin promote vascular thrombosis in mice 总被引:14,自引:5,他引:9
Occlusive thrombosis depends on the net balance between platelets, coagulation, and fibrinolytic factors. Epidemiologic information suggests that plasminogen activator inhibitor-1 (PAI-1), a central regulator of the fibrinolytic system, plays an important role in determining the overall risk for clinically significant vascular thrombosis. Vitronectin (VN), an abundant plasma and matrix glycoprotein, binds PAI-1 and stabilizes its active conformation. This study assessed the role of PAI-1 and VN expression in the formation of occlusive vascular thrombosis following arterial or venous injury. The common carotid arteries of 17 wild-type (WT) mice and 8 mice deficient in PAI-1 were injured photochemically while blood flow was continuously monitored. WT mice developed occlusive thrombi at 52.0 +/- 3.8 minutes (mean +/- SEM) following injury; mice deficient in PAI-1 developed occlusive thrombosis at 127 +/- 15 minutes (P <.0001). Mice deficient in VN (n = 12) developed vascular occlusion 77 +/- 11 minutes after injury, intermediate between the values observed for WT mice (P <.03) and mice deficient in PAI-1 (P <.01). PAI-1 and VN also affected the time to occlusion after injury to the jugular vein. Three WT mice developed occlusive venous thrombosis an average of 39.7 +/- 1 minutes following the onset of injury, whereas the jugular veins of 4 mice deficient in PAI-1 and 4 deficient in VN occluded 56.7 +/- 5 and 58.7 +/- 2 minutes, respectively, following injury (P <.04 and P <.01 compared to WT mice). These results suggest that endogenous fibrinolysis and its regulation by PAI-1 and VN have important roles in the development of occlusive vascular thrombosis after vascular injury. (Blood. 2000;95:577-580) 相似文献
12.
Although exposure of LLC-PK1 epithelial cell sheets to phorbol esters (TPA)
causes a near immediate and total decrease of transepithelial electrical
resistance (TER), continuation of exposure for 3 to 4 days results in a
tachyphylactic response as TER begins to return to control levels. Recovery
of TER is maximal by 5 to 6 days, but reaches only 70 to 80% of control
level. A reciprocal change in the transepithelial flux of D-mannitol
indicates that the TER decrease is indicative of an increase in tight
junction permeability. Exposure of cell sheets to TPA for several days also
results in the appearance of multilayered polyp- like foci (PLFs) across
the otherwise one cell layer thick cell sheets. The pattern of penetration
of the electron dense dye, ruthenium red, from the apical surface, across
the tight junction and into the lateral intercellular space indicates that
the tight junctions of the cell sheet become uniformly leaky after acute
exposure to TPA. However, when exposure is continued for several days, only
the junctions of cells in the PLFs manifest leakiness. The decrease in TER
following acute TPA exposure correlates with the translocation of protein
kinase C-alpha (PKC alpha) into a membrane-associated compartment. With
exposure of several days, only a trace of PKC alpha is visible by Western
immunoblot, and this is in the membrane-associated compartment.
Immunofluorescent microscopy indicates that the trace of PKC alpha seen in
the Western immunoblots is ascribable distinctly to cells of the PLFs.
Monolayer areas between PLFs show no discernible immunofluorescent signal.
The data therefore indicate that tight junction barrier function may be
restored in certain areas by the down regulation of PKC alpha from the
membrane-associated compartment. Failure to down regulate may result in the
paracellular leakiness and abnormal cell architecture of the PLFs. Possible
implications of this model for in vivo epithelial tumor promotion are
discussed.
相似文献
13.
Molecular analysis of PKU in Ireland 总被引:1,自引:0,他引:1
CA O'Neill RC Eisensmith DT Croke ER Naughten SF Cahalane SLC Woo 《Acta paediatrica (Oslo, Norway : 1992)》1994,83(S407):43-44
Classical phenylketonuria (PKU: McKusick No. 261600) is caused by mutations occurring at the phenylalanine hydroxylase (PAH) locus on chromosome 12 and has a prevalence in Ireland of 1 in 4500. We examined 304 independent alleles from 350 patients for the presence of six mutations and have characterized VNTR alleles within the minisatellite region 3' to the PAH gene in patients carrying the most prevalent mutation. R408W was the most common mutation found, with a relative frequency of 42%. All other mutations had relative frequencies of <10%. VNTR analysis showed that the R408W mutation is associated with the VNTR-8 allele in the Irish population, indicating that R408W is associated with RFLP haplotype 1. This differs from that reported from eastern Europe where R408W is associated with RFLP haplotype 2/VNTR-3; an observation which has led several groups to propose a Balto-Slavic origin for this mutation. These results support the hypothesis of a second, independent founding event for the R408W mutation on an RFLP haplotype 1 VNTR-8 chromsome background in the Irish/Celtic population. 相似文献
14.
15.
Pulmonary fibrosis is increased in mice carrying the factor V Leiden mutation following bleomycin injury 总被引:1,自引:0,他引:1
Increased fibrin deposition following inflammatory lung injury has been proposed to facilitate the development of pulmonary fibrosis. Therefore, factors predisposing to thrombosis may affect the fibrotic response to injury. Activated protein C (aPC) resistance due to the factor V Leiden mutation (FvL) is a common genetic risk factor for vascular thrombosis. To examine the relationship between aPC resistance and the development of pulmonary fibrosis, lung inflammation was induced by bleomycin in mice carrying the FvL mutation. Three weeks following the instillation of 0.0375 U of bleomycin, the lungs of mice homozygous and heterozygous for FvL contained significantly more hydroxyproline (35 +/- 4 and 36 +/- 7 ug hydroxyproline/mg total protein, respectively) than wild-type mice (26 +/- 6 ug/mg protein, p <0.01 for both comparisons). These data demonstrate a strong relationship between aPC resistance and the pulmonary fibrosis that occurs following inflammatory lung injury. 相似文献
16.
Katja Nelson DDS Detlef Hildebrand DMD DT Juergen Mehrhof MDT 《Journal of prosthodontics》2008,17(7):591-595
This article describes a method of fabricating a fixed retrievable implant‐retained prosthesis based on electroforming. This method combines the advantages of both the cement‐ and screw‐retained prostheses, including passive fit, ease of fabrication, and retrievability. The absence of visible occlusal screw‐canals adds to its increased esthetic appeal. 相似文献
17.
Schizencephaly: diagnosis and progression in utero 总被引:2,自引:0,他引:2
Schizencephaly is an unusual condition of obscure etiology. Most theories of pathogenesis postulate an in utero insult leading to maldevelopment rather than destruction of brain. The cause has most often been described as vascular or idiopathic dysgenesis. The authors report a case in which two in utero ultrasound (US) examinations performed at 31 and 36 menstrual weeks demonstrated progressive deterioration of the relatively narrow, symmetrical clefts connecting the lateral ventricles with the subarachnoid space into broad defects that corresponded to the entire distribution of the middle cerebral arteries. The findings in this case document progressive destruction of brain tissue in utero and are consistent with a vascular cause rather than a failure of formation of portions of the cerebral mantle. 相似文献
18.
A highly sensitive and specific chemiluminescent enzyme-linked immunosorbent assay for diagnosis of active Trypanosoma cruzi infection 总被引:1,自引:0,他引:1
BACKGROUND: Chagas' disease is transmitted to man either by the bite of insects harboring Trypanosoma cruzi or by the transfusion of blood from infected donors. The conventional serologic testing as presently used in blood banks in South America is unsatisfactory, because of a high number of inconclusive and false-positive results. Other methods such as polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) with recombinant antigens have been proposed, but inherent difficulties have so far precluded their adoption in the large-scale screening required by blood banks. STUDY DESIGN AND METHODS: A highly sensitive and specific chemiluminescent ELISA using a purified trypomastigote glycoconjugate antigen and a complex epimastigote antigen was devised for the diagnosis of active T. cruzi infection. RESULTS: Chemiluminescent ELISA was 100-percent sensitive in the diagnosis of 100 cases of confirmed Chagas' disease. Inconclusive results and false-positive reactions were eliminated in a panel of 115 sera.The specificity of the chemiluminescent ELISA was 100 percent with a purified trypomastigote glycoconjugate antigen and 99.7 percent with a complex epimastigote antigen when applied to 1000 normal human sera and 288 heterologous sera from patients with other infections, including leishmaniasis, and vaccinated individuals. CONCLUSION: The chemiluminescent ELISAs provide a test that is highly sensitive (purified trypomastigote glycoconjugate and complex epimastigote antigens) and specific (purified trypomastigote glycoconjugate antigen) for Chagas' disease diagnosis. It can be used in blood bank screening and to monitor the treatment of patients undergoing chemotherapy. 相似文献
19.