温固化水凝胶复合细胞外基质与膀胱平滑肌细胞的相容性

目的:选用膀胱平滑肌细胞为实验细胞,评估细胞外基质/温度敏感性水凝胶复合支架材料的生物相容性。方法:实验于2005-02/05在武汉大学人民医院泌尿外科研究室完成。①实验分组:实验分为4组。细胞外基质/温度敏感性水凝胶复合支架组:细胞外基质/温度敏感性水凝胶复合支架种植平滑肌细胞;单纯细胞外基质组:单纯细胞外基质种植平滑肌细胞;阴性对照组:单纯培养平滑肌细胞;空白对照组:无细胞培养液。②实验操作:种植细胞前先用培养液将支架材料预湿,取第3代兔膀胱平滑肌细胞悬液(1×108L-1)50μL缓慢接种于材料上。③实验评估:培养2d后倒置相差显微镜下观察细胞黏附、生长情况以及扫描电镜下观察细胞在材料上的空间生长情况;培养5,10d取细胞外基质/温度敏感性水凝胶复合支架组、单纯细胞外基质组材料,进行细胞计数,观察细胞黏附数量;培养1,3,5,7d时MTT法检测细胞的活力。结果:①相差显微镜下可见细胞外基质/温度敏感性水凝胶复合材料为红染的网状结构,纤维较粗,网孔直径较小,未见到细胞碎片;种植平滑肌细胞后6h,可见细胞紧密黏附于材料表面;种植平滑肌细胞后12h,可见细胞已伸展,有多个突起;培养3d时,贴附于材料的细胞数量增加,细胞增殖明显。②扫描电镜下可见发育良好的细胞附于材料上,伪足沿纤维伸展,附着牢固,细胞间连接紧密,可见到细胞外基质分泌。③膀胱平滑肌细胞在单纯细胞外基质上黏附性良好,黏附率为87.6%,复合温度敏感性水凝胶后的细胞外基质表面黏附能力较之增强,黏附率为96.7%。④细胞活力:细胞外基质/温度敏感性水凝胶复合支架组、阴性对照组细胞活力(A)高于单纯细胞外基质组,差异有显著性意义(P<0.05,0.01),培养1,3,5d细胞外基质/温度敏感性水凝胶复合支架组细胞活力(A)低于阴性对照组,培养7d高于阴性对照组,差异有显著性意义(P<0.05,0.01)。结论:细胞外基质/温度敏感性水凝胶复合材料具有便于细胞黏附和生长的微孔结构,生物相容性好,并且保留的某些成分具有良好的促组织再生作用,是一种理想的组织工程材料。     

Crossover use of donated blood for autologous transfusion: report of the Council on Scientific Affairs, American Medical Association

BACKGROUND: Controversy exists concerning whether the costs and potential risks outweigh the potential benefits of "crossover" use in the general blood supply of unutilized blood that was donated for autologous transfusion. STUDY DESIGN AND METHODS: Published articles and reports were identified through systematic search of MEDLINE and review of references cited in previously identified articles, textbooks, and reports. Consultation was made with experts in blood donation and transfusion. Additional peer review was received from the American Medical Association (AMA) Council on Scientific Affairs RESULTS: Concern over infectious disease transmission has led to increased interest in and support for autologous transfusion for individuals having planned surgeries. Different requirements exist for collection, labeling, and screening of blood to be used for autologous versus allogeneic transfusions; therefore, procedures for diverting autologous blood donations to the general blood supply involve considerable expense. Several cost-effectiveness studies of autologous blood donation and transfusion conclude that currently this "crossover" appears to be an expensive procedure yielding little increased benefit from a societal perspective. CONCLUSIONS: The recommendations in this report were adopted as AMA Policy at the AMA Annual Meeting in June 1997. The AMA does not encourage blood collection programs to "cross over" units donated for autologous use to the allogeneic blood supply. Practice guidelines are needed, and should be utilized to ensure parsimony in the use of autologous blood donations and transfusions.     

Screening for early pancreatic ductal adenocarcinoma in hereditary pancreatitis

Patients with hereditary pancreatitis have a 40% lifetime risk of developing pancreatic ductal adenocarcinoma. Existing methods of diagnosing pancreatic cancer such as tumor markers, endoscopy, and radiological imaging lack the sensitivity and specificity for early diagnosis, particularly in a background of chronic pancreatitis. Molecular based strategies offer new avenues of screening for pancreatic ductal adenocarcinoma in these high-risk patients, which may allow the development of highly sensitive and specific diagnostic tests for the early detection of cancer.     

Granulocyte transfusions: efficacy in treating fungal infections in neutropenic patients following bone marrow transplantation

Background: A retrospective study was conducted to evaluate the efficacy of granulocyte transfusions in neutropenic patients with fungal infections following bone marrow transplantation. Study Design and Methods: Systemic fungal infection was detected in 87 patients during the first 100 days following bone marrow transplantation; 50 received granulocytes in addition to appropriate antifungal agents. The median age was 17 years in the transfused patients (range, 1.5–57) and 35 years in the nontransfused patients (range, 0.8–50). Granulocyte transfusions were given on a daily to twice-daily basis. To evaluate their responses, patients were categorized by infection type (candidal [n = 38] vs. noncandidal [n = 49]) and site (fungemia alone [n = 30] vs. invasive infection [n = 57]). Resolution of infection was defined as the resolution of signs and symptoms and negative cultures and/or histopathology. Results: No benefit of granulocyte transfusions could be shown in the resolution of infection in patients with either invasive noncandidal infection (29% in the transfused patients vs. 23% in the nontransfused patients, p > 0.1) or candidal sepsis (56% vs. 50%, p > 0.1). Among patients with delayed marrow recovery, no difference was seen in the resolution of infection in the transfused (25.9%) and nontransfused (50%) patients (p > 0.1); nor was any difference between the transfused and nontransfused patients evident in the duration of febrile episode associated with the fungal infection. Granulocyte transfusions were well tolerated, with the only complications being fever in 12 patients (24%), chills in 10 (20%), and respiratory distress in 2 (4%). Despite attempts to stratify by infection type, invasiveness, and marrow recovery, it was not possible to show any benefit of granulocyte transfusions in this group. Conclusions: It is likely that only through a prospective randomized trial can the question of the efficacy of granulocyte transfusions in treating fungal infections be conclusively answered.     

Protection of human polymorphonuclear leukocyte function from the deleterious effects of isolation, irradiation, and storage by interferon-gamma and granulocyte-colony-stimulating factor

BACKGROUND: Fungal infections represent a difficult challenge to clinicians caring for neutropenic patients with hematologic malignancies, as antifungal therapy often has limited success in that setting. One promising yet problematic alternative approach is leukocyte transfusion. The isolation of polymorphonuclear leukocytes (PMNs) induces apoptosis and functional deterioration, and irradiation to prevent transfusion-associated graft-versus-host disease causes further functional deterioration. STUDY DESIGN AND METHODS: The ability of interferon-gamma and granulocyte-colony-stimulating factor (G-CSF), used both alone and in combination, to protect PMNs after 0 or 20 hours' storage in cell culture (as a model for function after transfusion) and irradiation with 0, 5, or 30 Gy was studied. RESULTS: Without cytokine treatment, 20-hour-old PMNs showed marked apoptosis, no appreciable chemotaxis, and no ability to kill Candida albicans. In contrast, cytokine treatment significantly reduced apoptosis and protected chemotaxis, C. albicans killing, and surface-receptor expression from both storage and irradiation. Although the majority of the benefit appeared to be due to G-CSF, consistent trends suggested better function of PMNs after combined treatment with interferon-gamma and G-CSF. CONCLUSION: Judicious use of cytokines may preserve PMN function. These findings have important implications for the transfusion of PMNs to cytopenic patients.     

Buffy coat platelets stored in apyrase, aprotinin, and ascorbic acid in a suspended bag: combined strategies for reducing platelet activation during storage

BACKGROUND: Platelet activation is an important factor impeding the clinical effectiveness of platelet transfusions. In this study, platelet concentrates (PCs) were prepared by a novel suspended-bag buffy coat technique that was followed by the addition of a mixture of platelet activation inhibitors to the storage bag. STUDY DESIGN AND METHODS: In vitro platelet function was evaluated in PCs prepared by the suspended-bag buffy coat technique and stored at 22 degrees C for 5 days in the presence of (n = 12) or absence (n = 12) of apyrase, ascorbic acid, and aprotinin (AAA). RESULTS: Platelets from AAA- incubated PCs demonstrated mean ATP levels 17 percent (p < 0.004), 13 percent (p < 0.02), and 22 percent (p < 0.003) higher than those measured in parallel control PCs on Days 1, 3, and 5, respectively. Similarly, on Days 3 and 5 of storage, respectively, 45-percent (p < 0.001) and 50-percent (p < 0.001) greater ADP-induced maximum aggregation was observed in AAA-incubated PCs than was seen in control preparations. AAA-incubated PCs demonstrated alpha-granule membrane protein-140 expression 92 percent (p < 0.01), 133 percent (p < 0.003), and 104 percent (p < 0.001) below that in control PCs on Days 1, 3, and 5, respectively. At similar intervals, a significant increase in recovery from hypotonic shock also was observed in AAA-incubated PCs. Further, Day 5 AAA-PCs demonstrated significantly higher morphology scores and O2 consumption than did control preparations. CONCLUSION: Buffy coat platelets prepared in suspended bags and stored in the presence of AAA demonstrate significantly reduced activation and enhanced functional and metabolic activity.     

Influence of a 12-hour, 22 degrees C holding period for buffy coats on the preparation of platelet concentrates stored in plasma

BACKGROUND: The preparation of platelet concentrates (PCs) from buffy coats (BCs) stored at room temperature is controversial, because of the strong metabolic activity of cells in BCs and the possible detrimental effect of neutrophil enzymes on platelets when the holding time before separation is prolonged. Despite good in vitro and in vivo behavior of BC-PCs stored in synthetic solution, little is known of the quality of BC-PCs stored in plasma. STUDY DESIGN AND METHODS: Comparison was made of PCs prepared from BCs held at 22 degrees C for 3 hours (3-hour BC- PCs) or overnight (12-hour BC-PCs) and stored in plasma. Platelet and white cell counts, pH, response to osmotic shock, and morphologic scores were determined on 20 PCs of each type. The decrease in dense granule and alpha granule content, a marker of platelet activation, were estimated by mepacrine counting and beta-thromboglobulin measurement, respectively (n = 8–10). Platelet function was studied in terms of aggregation and thromboxane production in response to various concentrations of collagen and thrombin (n = 8–17). PCs prepared from unstored BCs (n = 15) and from BCs held for 90 minutes (n = 15) were used as controls. RESULTS: Platelet yield was increased from 53 +/? 10 percent of donated platelets to 73 +/? 4 percent by increasing the BC holding time from 0 to 90 minutes to 3 hours (p < 0.001). Similar yields (7.8 +/? 1.8 vs. 7.9 +/? 2 × 10(10) platelets) and white cell contamination (0.9 +/? 0.8 vs. 1.0 +/? 0.9 × 10(7)) were obtained with 3-hour and 12-hour BC-PCs. At the end of the storage period (Day 5), all variables known to correlate with platelet survival in vivo were well maintained in both 3-hour and 12-hour BC-PCs: pH > or = 6.9, response to osmotic shock > or = 70 percent, and morphology scores always > or = 240. During storage, the dense granule content decreased moderately (30% after 5 days), whatever the conditions. By contrast, the total platelet beta-thromboglobulin content was better preserved in 12-hour BC-PCs than in 3-hour BC-PCs (p < 0.04). No significant differences were observed in collagen-induced aggregation and thromboxane production in the two PC preparations. However, aggregation responses to thrombin were higher in 12-hour BC-PCs on Day 5 of storage (p < 0.01). CONCLUSION: BCs can be held at 22 degrees C for up to 12 hours, with no detrimental effect on the quality of PCs stored for up to 5 days in plasma. Such a holding time might help overcome logistic problems in blood banks     

American Red Cross experience with routine testing for hepatitis B core antibody

The implementation of routine testing of blood donations for hepatitis B core antibody (anti-HBc) has allowed the characterization of the performance of the test in a large number of samples from apparently healthy individuals. This study reports the experience of the American Red Cross in testing 2.3 million donors for anti-HBc. The test protocol reproducibly identified a distinct population of donors. The anti-HBc-positive rate varied by region of the continental United States and by the time of year. In a case-control study, 85 percent of subsequent donations from anti-HBc-positive donors were anti-HBc positive. The predictions made in an earlier pilot study regarding the performance and impact of the test were borne out.     

Influence of the HLA-DRB1 locus on susceptibility and severity in rheumatoid arthritis

We examined HLA-DR genotype risk in 288 patients with rheumatoid arthritis who were carefully categorized for disease severity. Five hundred ethnically-matched bone-marrow donors were controls. A hierarchy of positive allelic associations was noted with DRB1*0401 (p < 10(-38), *0404,8 (p < 10(-43), *0405 (p < 10(-8), *10 (p < 10(-3) and *0101,2 (p < 10(-2), while DRB1*0403 was negatively associated (p = 0.02). The DRB1 genotype relative risks (and 95% CIs) for RA were: *0404,5,8/*0404,5,8 = 36.2 (15-87), *0401/*0404,5,8 = 31.3 (18-55), *401/*0401 = 18.8 (11-35), *0101,2/*0404,5,8 = 6.0 (2-14), *0101,2/*0401 = 6.4 (3-12), *0101,2/*0101,2 = 1.3 (0.3-6), *10/*0404,5,8 = 27.8 (5-148), *10/*0401 = 20.8 (5-89), *10/*0101,2 = 22.3 (5-96), *0404,5,8/DRX = 5.0 (3-8), *0401/DRX = 4.7 (3-7), *0101,2/DRX = 2.3 (1.4-4), *10/DRX = 3.4 (0.8-14). No significant correlation of DRB1 genotypes was found with severity of RA as judged by nodules or articular erosions.      

Long-term frequent plasma exchange donation of cryoprecipitate

Plasma exchange donation accomplishes the selective donation of cryoprecipitate. It facilitates the repeated donation of large quantities of factor VIII by individual donors and reduces donor exposure for recipients. A highly motivated donor is described who has undergone 103 donations between May 1983 and March 1987, producing 359,460 IU of factor VIII and supplying all the factor VIII needed since August 1983 by his severely affected hemophiliac son, now age 14. The donor has remained in good health, and no significant abnormalities have been noted in hematologic, biochemical, immunologic, coagulation, and serum protein testing. Extensive experience with this donor suggests that repeated plasma-exchange donation is safe and can sometimes allow single-donor support of severe hemophiliacs.