组织工程支架材料偏磷酸钙玻璃陶瓷的多孔性能

文章采用二次烧结法,没有添加发泡剂,制备了一种新型泡沫多孔玻璃陶瓷,主要考察了其多孔性能,分析了其成孔机制并作出成泡沫假设,验证其降解性能和生物相容性能。多孔玻璃陶瓷的制备过程中没有采用发泡剂,但材料可以发泡成孔,材料的配方中,其钙磷物质的量比为0.47,烧结温度选择680℃。X射线衍射图谱证实所得多孔玻璃陶瓷主晶相为偏磷酸钙(β-Ca(PO3)2,CMP)。液体(水)静力称重法计算出其吸水率、显气孔率及体积密度分别为34.6%,43.6%和1.26g/cm3,与树脂成孔法结果类似。扫描电镜图显示,偏磷酸钙玻璃陶瓷孔隙丰富,大孔(100～300μm)和微孔(2～20μm)相互贯通。降解性能检测显示,偏磷酸钙块浸泡于37℃生理盐水28d,失重率9.2%;扫描电镜显示其表面形貌有较大的改变,出现了一些细小条状物质,原因需进一步的分析。细胞实验显示,人骨髓间充质干细胞在偏磷酸钙孔洞里大量生长,且与偏磷酸钙材料表面结合紧密。提示采用二次烧结工艺,无需添加发泡剂,利用其自身配方和性质即可以制备多孔偏磷酸钙玻璃陶瓷,其发泡的主要原因为不定相偏磷酸钙的降解能力强。降解实验和生物相容实验表明所得偏磷酸钙玻璃陶瓷是一种非常有潜力的组织工程支架材料。     

Promotion of high school blood donations: testing the efficacy of a videotaped intervention

"Life to Life," an 11-minute videotape based on social learning principles, was used by 10 blood centers in presentations to 4970 high school students one week before school blood drives. At each school, some students saw the videotape and others attended a blood center's customary presentation. Students also completed a brief questionnaire assessing donation attitudes, donation history, and intent to donate. The videotape accounted for a relative increase of 18.7 percent in donations even when other factors were not controlled for. Results were analyzed with logistic models and showed a consistently positive effect over all models used. For students who had never donated, the estimated odds ratio for actual donation (videotape:control) was 1.528. When the model included both type of presentation and ethnicity, the relative increase in donation over that after the blood centers' usual presentation was 69.8 percent for first-time donors. Among previous donors considered alone, the effect on donation was not significant. Whatever their donor history, students who viewed the videotape showed significantly more positive attitudes toward donation and had greater intention to donate than students who saw the blood centers' standard presentations. These results suggest that this videotape is a useful tool for recruitment of high school blood donors.     

Identification and characterization of an HIV-2 antibody-positive blood donor in the United States

BACKGROUND: As of June 1, 1992, the Food and Drug Administration recommended that all donated blood be screened for antibodies specific to HIV-2. Despite broad serologic surveillance, only two cases of HIV-2 infection had been detected among potential blood and plasma donors since the implementation of the test. CASE REPORT: The identification of a third HIV-2 antibody-positive blood donor is reported. The first- time donor was identified by routine screening procedures as anti-HIV- 1/HIV-2-reactive, and that status was confirmed by licensed HIV-1 Western blot. Concurrent whole-virus lysate enzyme immunoassay and Western blot for HIV-2 were strongly positive, but the possibility of HIV-1 cross-reactivity could not be eliminated. The donor was notified, counseled, and deferred from future donation. He subsequently enrolled in a Centers for Disease Control and Prevention-sponsored epidemiologic study of HIV-positive former donors. When it was revealed during the standardized interview that he was a native of an HIV-2-endemic region, follow-up samples were submitted to the Centers for Disease Control and Prevention. Investigational HIV-1 and HIV-2 peptide enzyme immunoassays indicated that this infection was due to HIV-2 only. CONCLUSION: Enzyme immunoassays for antibodies to synthetic peptides of HIV-1 and HIV-2 may be useful in differentiating the two viruses in individuals with ambiguous Western blot results and risk factors for HIV-2 infection.     

Improvement in migraine-specific quality of life in a clinical trial of rizatriptan

A validated migraine-specific questionnaire (24-h Migraine Quality of Life Questionnaire1: 24-h MQoLQ) was used to assess the impact of migraine and migraine therapy on health related quality of life during an acute migraine attack. Male and female migraineurs aged 18-55 years were randomized to placebo ( n = 41), rizatriptan 2.5 mg ( n = 47), 5 mg ( n = 74), or 10 mg ( n = 85) in a triple-blind, placebo-controlled clinical trial. Rizatriptan 5 mg and 10 mg were significantly more efficacious than placebo on pain relief and functional disability. After accounting, for multiple comparisons to placebo, rizatriptan 10 mg showed significantly better responses compared to placebo on three of five domains of 24-h MQoLQ (social functioning, migraine symptoms, and feelings/concerns). The O'Brien's Rank Sum Test statistic showed a statistically significant overall difference on the 24-h MQoLQ between the 10 mg rizatriptan and placebo groups ( p = 0.005) and for the overall close trend ( p 0.001).     

Recombinant Miltenberger I and II human blood group antigens: the role of glycosylation in cell surface expression and antigenicity of glycophorin A

Glycophorin A is a heavily glycosylated glycoprotein (1 N-linked and 15 O-linked oligosaccharides) and is highly expressed on the surface of human red blood cells. It is important in transfusion medicine because it carries several clinically relevant human blood group antigens. To study further the role of glycosylation in surface expression of this protein, four mutations were separately introduced into glycophorin A cDNA by site-directed mutagenesis. Each of these mutations blocks N- linked glycosylation at Asn26 of this glycoprotein by affecting the Asn- X-Ser/Thr acceptor sequence. Two of these mutations are identical to the amino acid polymorphisms found at position 28 in the Mi.I and Mi.II Miltenberger blood group antigens. The mutated recombinant glycoproteins were expressed in transfected wild-type and glycosylation- deficient Chinese hamster ovary (CHO) cells. When expressed in wild- type CHO cells and analyzed on Western blots, each of the four mutants had a faster electrophoretic mobility than wild-type glycophorin A, corresponding to a difference of approximately 4 Kd. This change is consistent with the absence of the N-linked oligosaccharide at Asn26. Each of the four mutants was highly expressed on the surface of CHO cells, confirming that, in the presence of normal O-linked glycosylation, the N-linked oligosaccharide is not necessary for cell surface expression of this glycoprotein. To examine the role of O- linked glycosylation in this process, the Mi.I mutant cDNA was transfected into the IdlD glycosylation-deficient CHO cell line. When the transfected IdlD cells were cultured in the presence of N- acetylgalactosamine alone, only intermediate levels of cell surface expression were seen for Mi.I mutant glycophorin A containing truncated O-linked oligosaccharides. In contrast, when cultured in the presence of galactose alone, or in the absence of both galactose and N- acetylgalactosamine, Mi.I mutant glycophorin A lacking both N-linked and O-linked oligosaccharides was not expressed at the cell surface. This extends previous results (Remaley et al, J Biol Chem 266:24176, 1991) showing that, in the absence of O-linked glycosylation, some types of N-linked glycosylation can support cell surface expression of glycophorin A. The glycophorin A mutants were also used for serologic testing with defined human antisera. These studies showed that the recombinant Mi.I and Mi.II glycoproteins appropriately bound anti-Vw and anti-Hut, respectively. They also demonstrated that these antibodies recognized the amino acid polymorphisms encoded by Mi.I and Mi.II rather than cryptic peptide antigens uncovered by the lack of N- linked glycosylation.     

Cytokine-mediated regulation of transferrin synthesis in mouse macrophages and human T lymphocytes

Transferrin (Tf) plays an important role during immunologic activation by donating iron to activated lymphocytes. Therefore, synthesis by lymphomyeloid cells has been investigated. Mouse macrophages and macrophage cell lines synthesized Tf, with levels being markedly increased by gamma-interferon (gamma-IFN) and, to a lesser extent, by interleukin-1 beta (IL-1 beta), IL-6, and tumor necrosis factor alpha (TNF alpha). Tf was also produced by phytohemagglutinin-stimulated human T cells and two T-cell lines and was increased by IL-2. Even after appropriate activation, none was synthesized by human macrophages or monocytic cell lines or by mouse T cells, T-cell lines, or thymus cells. In both species, B-lineage cell lines were negative. Tf was also synthesised by macrophages from congenitally hypotransferrinemic mice and was responsive to gamma-IFN, but levels were lower than those from normal controls. Synthesis by human and murine hepatoma cells was increased by IL-6 but unaffected by IL-1, TNF alpha, or gamma-IFN. Iron decreased synthesis by hepatoma cells but had no effect on the lymphomyeloid cells. Tf mRNA levels paralleled protein synthesis, suggesting that regulation was pre-translational. Thus, Tf synthesis by lymphomyeloid cells is regulated differently from hepatic synthesis, which is consistent with the suggestion that Tf may act in a paracrine (mouse) or autocrine (human) manner on activated lymphocytes.     

T-cell-depleted autologous bone marrow transplantation therapy: analysis of immune deficiency and late complications

Fourteen patients with T-cell-derived leukemia and lymphoma underwent high-dose chemoradiotherapy and anti-T-cell monoclonal antibody-treated autologous bone marrow transplantation (ABMT). All patients were either in sensitive relapse or had adverse prognostic features, and five patients had a history of bone marrow involvement with disease. Patients received a median of 2 (1 to 3) prior chemotherapy regimens; 10 patients received local radiotherapy. After high-dose ablative therapy, greater than 500/mm3 granulocytes and greater than 20,000 untransfused platelets/mm3 were noted at a median of 23 (13 to 48) and 26 (15 to 43) days post-ABMT, respectively. Natural killer (NK) cells, T cells (predominantly T8+), and monocytes were noted within the first 1 to 2 months post-AMBT, as seen in other series. Disease-free survival was a median of 10.1 months, 5.9 months for patients with T acute lymphoblastic leukemia or lymphoblastic lymphoma and 25.6 months for patients with T non-Hodgkin's lymphoma (NHL). Toxicities were common and severe. Thirty-six percent of patients developed bacteremias early post-BMT. Late complications included a skin rash consistent with graft versus host disease; infections with Herpes zoster, hepatitis, and Pneumocystis carinii; and the development of Epstein-Barr virus associated lymphoproliferative syndrome. Our findings suggest that patients who have undergone T-depleted ABMT have a profound immunodeficiency not reflected in the phenotypic reconstitution of the T and NK cells. Characterization of the functional deficiency may facilitate the development of methods to reduce the long-term toxicity of AMBT in these patients.     

Rearrangement of both immunoglobulin and T-cell receptor genes in a prolymphocytic variant of hairy cell leukemia patient resistant to interferon-alpha [published erratum appears in Blood 1989 Feb;73(2):624]

We describe a patient with the so-called "prolymphocytic variant" form of hairy cell leukemia (HCL) resistant to treatment with interferon- alpha (IFN-alpha). Analysis of immunoglobulin (Ig) and T-cell receptor- beta (TCR beta) gene rearrangements from serial peripheral blood mononuclear cell specimens (MNCs) confirmed not only the B-cell nature of the disease, but also the subsequent emergence of a morphologically indistinguishable population of cells with a clonal TCR beta rearrangement in addition to the original Ig gene rearrangement. With the exception of a transient increase in peripheral blood T cells during treatment with deoxycoformycin (DCF), the MNCs remained essentially constant throughout therapy with no evidence of a co- existing T-cell clone to account for the TCR beta rearrangement. Although MNCs from this patient bound significantly less IFN-alpha than did MNCs from other HCL patients, the binding was of high affinity with a kd similar to that of control cells. The number of IFN-gamma receptors on our patient's MNCs was four times higher than the number of IFN-alpha receptors and was similar to the number of IFN-alpha receptors on MNCs from HCL patients responsive to IFN-alpha. While various treatments including IFN-alpha, DCF, chlorambucil, splenectomy, leukopheresis, and IFN-gamma were not able to change the clinical progression of the disease, they may have provided an opportunity for the divergent TCR beta rearranged clone to expand and displace the initially dominant clone.