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41.
Immunoglobulin G from patients with heparin-induced thrombocytopenia binds to a complex of heparin and platelet factor 4 总被引:6,自引:3,他引:6
Heparin-induced thrombocytopenia (HIT) is an important complication of heparin therapy. Although there is general agreement that platelet activation in vitro by the HIT IgG is mediated by the platelet Fc receptor, the interaction among the antibody, heparin, and platelet membrane components is uncertain and debated. In this report, we describe studies designed to address these interactions. We found, as others have noted, that a variety of other sulfated polysaccharides could substitute for heparin in the reaction. Using polysaccharides selected for both size and charge, we found that reactivity depended on two independent factors: a certain minimum degree of sulfation per saccharide unit and a certain minimum size. Hence, highly sulfated but small (< 1,000 daltons) polysaccharides were not reactive nor were large but poorly sulfated polysaccharides. The ability of HIT IgG to recognize heparin by itself was tested by Ouchterlony gel diffusion, ammonium sulfate and polyethylene glycol precipitation, and equilibrium dialysis. No technique demonstrated reactivity. However, when platelet releasate was added to heparin and HIT IgG, a 50-fold increase in binding of radio-labeled heparin to HIT IgG was observed. The releasate was then depleted of proteins capable of binding to heparin by immunoaffinity chromatography. Only platelet factor 4-immunodepleted releasate lost its reactivity with HIT IgG and heparin. Finally, to determine whether the reaction occurred on the surface of platelets or in the fluid phase, washed platelets were incubated with HIT IgG or heparin and after a wash step, heparin or HIT IgG was added, respectively. Reactivity was only noted when platelets were preincubated with heparin. Consistent with these observations was the demonstration of the presence of PF4 on platelets using flow cytometry. These studies indicate that heparin and other large, highly sulfated polysaccharides bind to PF4 to form a reactive antigen on the platelet surface. HIT IgG then binds to this complex with activation of platelets through the platelet Fc receptors. 相似文献
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Zorn A Joiner WM Lasker AG Shelhamer M 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2007,179(3):505-515
Humans readily make predictive saccades to periodic alternating targets. This predictive behavior depends on internal monitoring
of timing error of past saccades in order to determine the time of initiation of future saccades; our earlier studies have
confirmed this by finding correlations between latencies of consecutive predictive saccades. It is natural to consider that
timing error is determined by visual detection of the difference between the time the target appears and the time the eyes
arrive at the target; this in turn implies that saccades must actually be produced in order for their timing errors to be
determined and predictive saccade timing to be established. We tested this hypothesis by having subjects view alternating
visual targets while fixating a central target in order to eliminate saccade production. After six alternating target presentations,
subjects began tracking the alternating targets. Tracking performance was assessed with an error measure that compared saccade
latency and inter-saccade interval with desired values (zero and inter-stimulus interval, respectively). Errors in this Prior Viewing paradigm were compared to those from a conventional De Novo paradigm in which saccades began as soon as the alternating targets were presented. Saccades under Prior Viewing reached a low-error steady predictive state more rapidly than under De Novo tracking. The initial saccade under Prior Viewing had a higher latency than the others, suggesting that this saccade was reactive even though the paradigm is predictable;
other reasons for this higher latency include time to disengage from the fixation target and time required to pre-program
the initial set of saccades. The results show that visual detection of timing error from an actual motor act (saccades) is
not necessary to establish predictive saccadic pacing: sensory-only information from viewing the moving targets can help to
establish this predictive state. 相似文献
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Bertram Yuh Walter Artibani Axel Heidenreich Simon Kimm Mani Menon Giacomo Novara Ashutosh Tewari Karim Touijer Timothy Wilson Kevin C. Zorn Scott E. Eggener 《European urology》2014
Context
The role of robot-assisted radical prostatectomy (RARP) for men with high-risk (HR) prostate cancer (PCa) has not been well studied.Objective
To evaluate the indications for surgical treatment, technical aspects such as nerve sparing (NS) and lymph node dissection (LND), and perioperative outcomes of men with HR PCa treated with RARP.Evidence acquisition
A systematic expert review of the literature was performed in October 2012, searching the Medline, Web of Science, and Scopus databases. Studies with a precise HR definition, robotic focus, and reporting of perioperative and pathologic outcomes were included.Evidence synthesis
A total of 12 papers (1360 patients) evaluating RARP in HR PCa were retrieved. Most studies (67%) used the D’Amico classification for defining HR. Biopsy Gleason grade 8–10 was the most frequent HR identifier (61%). Length of follow-up ranged from 9.7 to 37.7 mo. Incidence of NS varied, although when performed did not appear to compromise oncologic outcomes. Extended LND (ELND) revealed positive nodes in up to a third of patients. The rate of symptomatic lymphocele after ELND was 3%. Overall mean operative time was 168 min, estimated blood loss was 189 ml, length of hospital stay was 3.2 d, and catheterization time was 7.8 d. The 12-mo continence rates using a no-pad definition ranged from 51% to 95% with potency recovery ranging from 52% to 60%. The rate of organ-confined disease was 35%, and the positive margin rate was 35%. Three-year biochemical recurrence–free survival ranged from 45% to 86%.Conclusions
Although the use of RARP for HR PCa has been relatively limited, it appears safe and effective for select patients. Short-term results are similar to the literature on open radical prostatectomy. Variability exists for NS and the template of LND, although ELND improves staging and removes a higher number of metastatic nodes. Further study is required to assess long-term outcomes. 相似文献47.
48.
Graft-versus-tumor response in patients with multiple myeloma is associated with antibody response to BCMA, a plasma-cell membrane receptor 总被引:2,自引:1,他引:2
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Bellucci R Alyea EP Chiaretti S Wu CJ Zorn E Weller E Wu B Canning C Schlossman R Munshi NC Anderson KC Ritz J 《Blood》2005,105(10):3945-3950
Donor lymphocyte infusions (DLIs) induce effective graft-versus-tumor responses in patients with multiple myeloma who relapse after allogeneic hematopoietic stem-cell transplantation. The graft-versus-myeloma response is presumably mediated primarily by donor T cells, but recent studies have also demonstrated the presence of antibodies specific for a variety of myeloma-associated antigens in patients who achieve complete remission after DLI. One of the B-cell antigens identified in these studies was B-cell maturation antigen (BCMA), a transmembrane receptor of the tumor necrosis factor (TNF) superfamily that is selectively expressed by mature B cells. The present studies were undertaken to characterize the functional significance of antibodies to BCMA in vivo. Using transfected cells expressing BCMA, antibodies in patient serum were found to react with the cell-surface domain of BCMA. Post-DLI patient serum was able to induce complement-mediated lysis and antibody-dependent cellular cytotoxicity (ADCC) of transfected cells and primary myeloma cells expressing BCMA. BCMA antibodies were only found in post-DLI responders and not in other allogeneic transplant patients or healthy donors. These results demonstrate that BCMA is a target of donor B-cell immunity in patients with myeloma who respond to DLI. Antibody responses to cell-surface BCMA may contribute directly to tumor rejection in vivo. 相似文献
49.
Antibody responses to H-Y minor histocompatibility antigens correlate with chronic graft-versus-host disease and disease remission 总被引:7,自引:4,他引:7
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Miklos DB Kim HT Miller KH Guo L Zorn E Lee SJ Hochberg EP Wu CJ Alyea EP Cutler C Ho V Soiffer RJ Antin JH Ritz J 《Blood》2005,105(7):2973-2978
Minor histocompatibility antigens (mHAs) are known targets of donor T cells after allogeneic hematopoietic stem cell transplantation (HSCT). In contrast, B-cell responses to mHAs have not been extensively characterized and the clinical significance of antibodies to mHAs is unknown. We tested 121 patients who underwent HSCT and 134 healthy donors for immunoglobulin G (IgG) antibodies against 5 mHAs encoded by genes on the Y chromosome (DBY, UTY, ZFY, RPS4Y, and EIF1AY). Antibodies to at least one H-Y protein developed in 52% of male patients with female donors compared with 8.7% of male patients with male donors (P < .0001), and in 41.4% of healthy females compared with 7.8% of healthy males (P < .0001). H-Y antibodies develop 4 to 12 months after transplantation and persist for long periods. The clinical significance of H-Y antibodies was characterized in 75 male patients with hematologic malignancies who received stem cells from female donors (F --> M HSCT). The presence of H-Y antibodies correlated with chronic graft-versus-host disease (GVHD) by univariate (odds ratio [OR] = 15.5; P < .0001) and multivariable logistic regression analysis (OR = 56.5; P < .0001). Antibody response to Y-chromosome encoded histocompatibility antigens (H-Y antigens) was also associated with maintenance of disease remission (P < .0001). B cells may provide a new target for immune intervention in chronic GVHD. 相似文献
50.
After lethal irradiation of C57BL mice followed by the injection of 10(7) marrow cells, total cellularity and progenitor cell levels exceeded pretreatment levels within 12 days in the spleen, but regeneration remained incomplete in the marrow. The exceptional regenerative capacity of progenitor populations in the spleen was observed in organ cultures of spleen slices prepared 24 hr after irradiation and transplantation, excluding continuous repopulation from the marrow as a significant factor in splenic regeneration. 相似文献