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排序方式: 共有571条查询结果,搜索用时 31 毫秒
81.
TM Sankary ; G Yang ; JM Romeo ; PP Ulrich ; MP Busch ; BD Rawal ; GN Vyas 《Transfusion》1994,34(8):656-660
BACKGROUND: Since screening for antibody to hepatitis C virus (HCV) was introduced in 1990, posttransfusion hepatitis has been reduced to nearly background levels. This has led to reconsideration of the value of testing donated blood for elevated alanine aminotransferase (ALT). The contribution of ALT testing in detecting seronegative infection was evaluated by the performance of polymerase chain reaction (PCR) for hepatitis B virus (HBV) or HCV in plasma from ALT-elevated blood units. STUDY DESIGN AND METHODS: Testing was performed on 375 units of plasma, derived from an equivalent of 47,500 blood donations, with a highly sensitive hemi-nested PCR procedure. Using a triplet of primers directed at the conserved regions of HBV DNA and 5'-noncoding regions of HCV RNA, the hemi-nested PCR assay can reliably amplify 10 viral molecules to levels detectable in ethidium bromide-stained agarose gels. Pools of plasma from groups of four donors were screened with hemi-nested PCR. For any reactive pools, the plasma from individual donors was retested twice on different aliquots. RESULTS: Two of 375 units, both with midrange ALT elevation, were repeatedly reactive in hemi-nested PCR (one each for HBV DNA and HCV RNA). However, samples from the two suspect donors tested 9 and 5 months later revealed no seroconversion, elevated ALT, or viral genomes in hemi-nested PCR. CONCLUSION: The lack of confirmed HBV or HCV infection in this study representing an estimated 47,500 voluntary blood donations suggests that routine ALT testing for further prevention of posttransfusion hepatitis after exclusion of HBV- and/or HCV-seropositive blood may be superfluous. 相似文献
82.
The procoagulant subcellular matrix of stimulated endothelial cells that contains tissue factor (TF) was used to investigate the mechanism by which TF pathway inhibitor (TFPI) inhibits thrombin formation initiated by TF/factor VIIa (FVIIa) under flow conditions. Purified coagulation factors VII, X, and V and prothrombin were perfused at a wall shear rate of 100 s-1 through a flow chamber containing a coverslip covered with matrix of cultured human umbilical vein endothelial cells. This resulted in a TF- and FVII-dependent FXa and thrombin generation as measured in the effluent at the outlet of the system. Inhibition of this TF/FVIIa-triggered thrombin formation by TFPI purified from plasma was dependent on the amount of TF present on the endothelial cell matrix. The rate of prothrombinase assembly and steady-state levels of thrombin formation were decreased by TFPI. Because persistent albeit decreased steady-state levels of thrombin formation occurred in the presence of TFPI, we conclude that plasma- TFPI does not inhibit FXa present in the prothrombinase complex. The addition of FIX and FVIII to perfusates containing FVII and FX increased the FXa generation on endothelial matrices, and counteracted the inhibition of thrombin formation on endothelial cell matrices by TFPI. Our data provide further evidence for the hypothesis that the rapid inactivation of TF/FVIIa by TFPI in combination with the absence of either FVIII or FIX causes the bleeding tendency of patients with hemophilia A or B. 相似文献
83.
Phase II trial of 2-chlorodeoxyadenosine for the treatment of cutaneous T-cell lymphoma [see comments] 总被引:1,自引:0,他引:1
Kuzel TM; Hurria A; Samuelson E; Tallman MS; Roenigk HH Jr; Rademaker AW; Rosen ST 《Blood》1996,87(3):906-911
We investigated the efficacy of 2-chlorodeoxyadenosine (2-CdA) therapy in patients with mycosis fungoides (MF) and the Sezary syndrome (SS). Between February 1991 and November 1993, 21 patients with relapsed or refractory MF/SS were treated with 2-CdA. 2-CdA was administered by continuous intravenous infusion at a dose of 0.1 mg/kg/d for 7 days initially (13 patients), but was subsequently reduced to 5 days (nine patients) due to hematologic toxicity. All patients had failed to respond to at least one prior treatment for MF/SS (median number of total prior therapies, five; median number of systemic prior therapies, three) and had an Eastern Cooperative Oncology Group performance status of two or better. Cycles were administered at 28-day intervals. Assessable patients received at least 5 days of 2-CdA. Fourteen patients received more than one cycle of 2-CdA. An overall response rate of 28% was achieved. Three patients (14%) had a complete response with a median duration of 4.5 months (range, 2.5 to 16). Three (14%) had a partial response with a median duration of 2 months (range, 2 to 4). Fifteen patients (72%) had no response. The most significant toxicities encountered were bone marrow suppression (62% of patients) and infectious complications (62% of patients). Thirty-eight percent of patients experienced no toxicity from 2-CdA. 2-CdA has activity as a single agent in patients with previously treated relapsed MF/SS. Studies in less heavily pretreated individuals with 2-CdA alone or in combination will be undertaken. 相似文献
84.
85.
86.
The regulation of hemopoiesis in long-term bone marrow cultures. II. Stimulation and inhibition of stem cell proliferation 总被引:6,自引:1,他引:6
The isolation of a DNA synthesis inhibitor (NBME fraction IV) and stimulator (RBME fraction III) specific for the hemopoietic stem cell (CFU-s) from freshly isolated normal adult and regenerating murine bone marrow, respectively, has been well documented. We have utilized long- term liquid bone marrow cultures in a further analysis of the role of these factors in the regulation of CFU-s proliferation. Our results show that shortly after feeding, at a time when the cultured CFU-s are actively proliferating, high levels of the hemopoietic stem cell proliferation stimulator fraction III can be isolated from the culture medium. In contrast, the presence of essentially noncycling CFU-s found in cultures fed 8-10 days previously correlates with high levels of the hemopoietic stem cell inhibitor fraction IV. These results suggest that a certain balance between these factors determines CFU-s proliferation in the long-term cultures. In support of this, DNA synthesis in actively cycling CFU-s in the long-term cultures is inhibited for at least 3 days by the addition of excess NBME fraction IV (inhibitor). Furthermore, DNA synthesis in noncycling cultured CFU-s is stimulated for at least 5 days by the addition of RBME fraction III (stimulator). 相似文献
87.
We report a new bleeding disease--storage pool deficiency (SPD) of platelets--in pigs from the Mayo swine colony of homozygous von Willebrand's disease (vWD) and of heterozygous carriers of vWD. Levels of factor VIII, von Willebrand factor antigen (vWF:Ag), and ristocetin cofactor (RCof) were similar in the vWD carriers and SPD pigs. The latter pigs, however, had bleeding times of 15 minutes or more and were severe bleeders, in contrast to clinically normal vWD carriers. Platelet aggregation in response to collagen was reduced in most SPD pigs. Total platelet content of ADP, ATP, and serotonin was less than that of normal pigs. While the initial uptake of 14C-labeled serotonin into platelets was similar in SPD and normal pigs, retention of serotonin was reduced in platelets of SPD pigs. Transmission electron microscopy showed a large decrease of dense bodies in the platelets of SPD pigs. These findings support a diagnosis of SPD. Genetic analyses suggest an autosomal recessive mode of inheritance. A breeding program is under way to produce pigs affected only at the SPD gene, thus allowing further characterization of SPD and SPD-carrier pigs. 相似文献
88.
Molecular basis of the heterogeneity of expression of glycosyl phosphatidylinositol anchored proteins in paroxysmal nocturnal hemoglobinuria 总被引:2,自引:3,他引:2
Endo M; Ware RE; Vreeke TM; Singh SP; Howard TA; Tomita A; Holguin MH; Parker CJ 《Blood》1996,87(6):2546-2557
The purpose of these studies was to determine the molecular basis of the phenotypic mosaicism that is a defining feature of paroxysmal nocturnal hemoglobinuria (PNH). Analysis of T cell clones from a female patient revealed four distinct phenotypes based on surface expression of glycosyl phosphatidylinositol-anchored proteins (GPI-AP). When PIG-A (the gene that is mutant in PNH) from these clones was analyzed, four discrete somatic mutations were identified. Analysis of X chromosomal inactivation among the abnormal T cell clones was consistent with polyclonality. Together, these studies demonstrate that the phenotypic mosaicism that is characteristic of PNH is a consequence of genotypic mosaicism and that, at least in this case, PNH is a polyclonal rather than a monoclonal disease. That four distinct somatic mutations were present in a single patient suggests that in conditions that predispose to PNH PIG-A may be hypermutable. 相似文献
89.
Alpha 4 beta 1-integrin expression on sickle reticulocytes: vascular cell adhesion molecule-1-dependent binding to endothelium 总被引:7,自引:4,他引:7
Important complications in sickle cell anemia occur secondary to vascular occlusion, which is postulated to be initiated by interactions of erythrocytes with vascular endothelial cells. In patients with sickle cell anemia, up to 25% of reticulocytes express the alpha 4 beta 1-integrin complex. Furthermore, erythrocytes from patients with sickle cell anemia bind to endothelial cells activated by tumor necrosis factor alpha via (TNF alpha) via interactions between erythrocyte alpha 4 beta 1 and endothelial cell vascular cell adhesion molecule-1 (VCAM- 1). Thus, binding of alpha 4 beta 1-expressing reticulocytes to cytokine-activated endothelial cells may initiate vascular complications in sickle cell anemia and perhaps other hemolytic anemias during episodes of infection and inflammation. 相似文献
90.
James S Krinsley Moritoki Egi Alex Kiss Amin N Devendra Philipp Schuetz Paula M Maurer Marcus J Schultz Roosmarijn TM van Hooijdonk Morita Kiyoshi Iain MJ Mackenzie Djillali Annane Peter Stow Stanley A Nasraway Sharon Holewinski Ulrike Holzinger Jean-Charles Preiser Jean-Louis Vincent Rinaldo Bellomo 《Critical care (London, England)》2013,17(2):R37