Novel retinoic acid, 9-cis retinoic acid, in combination with all-trans retinoic acid is an effective inducer of differentiation of retinoic acid-resistant HL-60 cells

Recent studies have shown that a high proportion of patients with acute promyelocytic leukemia (APL) achieve complete remission after treatment with all-trans retinoic acid (RA). Nevertheless, despite an initial good response, most patients that received continuous treatment with all-trans RA relapse and develop RA-resistant disease. The 9-cis RA is a high-affinity ligand for retinoid X receptors (RXRs) and also binds efficiently to retinoic acid receptors (RARs); all-trans RA is a ligand for RARs. Both alone are able to induce differentiation of wild-type HL- 60 cells. We found that neither all-trans RA nor 9-cis RA (< 2 x 10(-6) mol/L) induced differentiation of RA-resistant HL-60 cells into either mature granulocytes or monocytes. However, morphologic differentiation of the RA-resistant HL-60 cells was induced by 10(-6) mol/L all-trans RA combined with various concentrations (10(-12) to 10(-6) mol/L) of 9- cis RA. Electron microscopic examination also confirmed that the combination of both retinoids induced RA-resistant HL-60 cells to differentiate to mature granulocytes. Functional analysis of differentiation (NBT reduction activity) confirmed the necessity of both analogs to induce differentiation. Also, expression of myeloid- specific differentiation antigens (CD11b and CD14) as well as migration inhibitory factor-related protein (MRP)-8/14 mRNAs were upregulated only in the presence of both retinoids in a dose-dependent manner. In these conditions 3H-thymidine incorporation was inhibited and numbers of viable cells were decreased, suggesting that all-trans RA with 9-cis RA may inhibit cell growth and induce differentiation of RA-resistant HL-60 cells into mature granulocytes. These studies suggest that 9-cis RA in combination with all-trans RA is an effective inducer of RA- resistant HL-60 cells and may have implications for both the biology of retinoids and clinical treatment of RA-resistant acute myelogenous leukemia, including APL patients.     

Myeloperoxidase: its structure and expression during myeloid differentiation

Myeloperoxidase (MPO) is a major protein present in myeloid cells and is used by these cells to help kill microbes. The human promyelocytic HL-60 line can be induced to differentiate to granulocytes or macrophagelike cells. Poly (A) containing RNA was isolated from HL-60 granulocytes, HL-60 macrophages, HL-60 blasts, and normal human granulocytes. The mRNA was translated in a reticulocyte lysate system in the presence of 35S-methionine. The MPO was precipitated from the lysate with rabbit IgG antiserum to human MPO. The resulting precipitate from HL-60 blasts gave a major band of radioactivity of approximately 77,000 daltons and another band at approximately 46,000 daltons on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The MPO identity of the labeled bands was confirmed by cold competition. The relative mRNA activity expressed as a percentage of radioactivity incorporated into MPO (77,000-dalton band) as compared with total trichloracetic acid (TCA) precipitable radioactivity was 0.2%. Negligible mRNA activity for MPO was present in HL-60 granulocytes, HL-60 macrophages, and normal human granulocytes. Pulse- chase experiments showed that MPO was an approximate 75,000-dalton major band and 77,000-dalton minor band of radioactivity after HL-60 blasts were labeled for 1/2 hour with 35S-methionine and the cell lysate immunoprecipitated and subjected to SDS-PAGE. The chase experiments (one to 24 hours) showed that the 77,000- and 75,000-dalton bands of radioactivity were replaced with two major bands (55,000 and 15,000 daltons) and one minor band (approximately 39,000 daltons) of radioactivity. Six-hour 35S-methionine labeling experiments showed that the relative rate of MPO synthesis compared with total TCA precipitable radioactivity was 0.5% in HL-60 blasts and almost negligible in HL-60 macrophages and granulocytes, normal human granulocytes, and B- lymphocytes. The KG-1 myeloblasts and KG-1a early myeloblasts synthesized a small amount of the 75,000-dalton MPO protein. Although HL-60 cells no longer synthesized MPO after differentiation, HL-60 granulocytes and HL-60 macrophages continued to contain MPO as measured by enzyme activity.(ABSTRACT TRUNCATED AT 400 WORDS)     

Detection of in vitro and in vivo cleavage of high molecular weight kininogen in human plasma by immunoblotting with monoclonal antibodies

Purified human high-mol-wt kininogen (HMWK), the cofactor of the contact phase of blood coagulation, migrated as a single band (approximately 110,000 mol wt) in a continuous buffer sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), but appeared as two separated bands (approximately 120,000 and 105,000 mol wt) when analyzed in a discontinuous buffer SDS-PAGE system. After elution from SDS polyacrylamide gels, each of the two bands showed coagulant activity. Six murine monoclonal antibodies (Mabs) against HMWK were produced and purified. In immunoblotting studies, three Mabs bound to the isolated alkylated heavy chain and one to the alkylated light chain of HMWK, whereas the remaining two bound only to the single-chain or unreduced two-chain molecule. None of the Mabs inhibited the clotting activity of HMWK or its binding to kaolin. Two of the Mabs, one directed against the light chain and one against the heavy chain, were used as specific probes to study HMWK in plasma samples using an immunoblotting technique. The anti-light chain Mab identified two distinct bands (approximately 120,000 and approximately 105,000 mol wt) in normal human plasma, but not in plasma from patients with hereditary HMWK deficiency. The anti-heavy chain Mab detected two additional bands (approximately 60,000 and approximately 54,000 mol wt) corresponding to low-mol-wt kininogen (LMWK) in normal plasma. A sensitive and specific quantitative immunoblotting assay of HMWK antigen in plasma was developed. Moreover, the immunoblotting technique with the anti-light chain Mab was used to detect the cleavage of HMWK in plasma samples after in vitro or in vivo activation of the contact system. The anti- light chain Mab demonstrated in vivo activation and cleavage of HMWK during an angioedema attack in a patient with hereditary angioedema and C1-inhibitor deficiency.     

Identification and quantitation of protein S in human platelets

Gel filtered human platelets contaminated with less than 0.02% of plasma protein S contained 490 ng of protein S antigen per 3 X 10(8) platelets, equivalent to 2.5% of protein S in whole blood. Three patients with heterozygous plasma protein S deficiency, a congenital disorder associated with venous thrombotic disease, had platelet protein S antigen levels that were 40% of the mean platelet level in ten normal volunteers. In immunoblotting analysis, platelet protein S was indistinguishable from plasma protein S. Thrombin stimulation of platelets caused release of 63% of total protein S antigen and this release was abolished when platelets were preincubated with metabolic inhibitors. Thrombin effected limited proteolysis of platelet protein S and this reaction was inhibited by calcium ions. Immunofluorescent staining of platelets using protein S antibodies demonstrated that protein S colocalized with fibrinogen, an established alpha-granule protein. Thus, human platelets contain protein S in alpha granules that can be released by thrombin stimulation. The released protein S may bind to stimulated platelets and thereby promote and localize the anticoagulant activity of activated protein C on the platelet surface.     

骨髓间充质干细胞在医学领域中的研究与应用

目的:骨髓间充质干细胞主要存在于全身结缔组织和器官间质中,自我更新和增殖能力强,在适宜的微环境里具有多向分化潜能。文章就骨髓间充质干细胞的生物学特性及其在医学领域应用的最新进展做一综述。资料来源:应用计算机检索PUBMED2000-01/2006-12期间的相关文章,检索词为“mesenchymal stem cell”,并限定文章语言种类为English。同时计算机检索中国期刊全文数据库2000-01/2006-12期间的相关文章,检索词为“骨髓间充质干细胞”,并限定文章语言种类为中文。资料选择:对资料进行初审,并查看每篇文献后的引文。纳入标准:文章所述内容应与骨髓间充质干细胞的发展现状及其临床应用相关。排除标准:重复研究或较陈旧的文献。资料提炼:共收集到160篇相关文献,68文献符合纳入标准,排除的92篇文献为内容陈旧或重复。选取符合纳入标准的30篇文献进行分析,分别涉及骨髓间充质干细胞的分离培养和鉴定、在医学领域中的应用、当前存在的问题及展望。资料综合:骨髓间充质干细胞是一类具有分裂增殖和多向分化潜能的干细胞,在适宜的诱导条件下可定向分化为成骨细胞、成软骨细胞、脂肪细胞、腱细胞、肌肉细胞和神经细胞等,且已在退行性及缺损性疾病、心血管疾病、肝移植、肺纤维化等疾病治疗方面取得良好效果。目前骨髓间充质干细胞在体内的细胞生物学和分子生物学作用机制仍不清楚,如何限定体内外诱导条件使其向所需细胞或组织定向分化以及移植时机、是否具有致瘤性等问题尚需深入研究。结论:骨髓间充质干细胞具有易获得、易培养、低免疫原性、易于外源基因的转入和表达等特性,已成为具有细胞治疗和基因治疗临床疾病潜在实用价值的有效载体。     

Strukturiertes klinisches Risikomanagement in einer Akutklinik

Background

A hospital is a dangerous place for patients. Multiple studies have demonstrated that errors are a significant problem in hospitals. At the same time it has been shown that a structured healthcare risk management offers numerous tools for risk reduction or risk prevention. The relevance of data due to errors in hospitals is unambiguous, therefore it is necessary to focus on this issue.

Objective

This article describes the basic principles and the implementation of a structured healthcare risk management. The process and tools of healthcare risk management are presented and explained.

Methods

A review of the literature on healthcare risk management was conducted and the currently used and established tools of healthcare risk management are presented.

Results

In the process of healthcare risk management several effective tools for the reduction and prevention of errors are available. These tools must be established in a structured risk management process.

Conclusion

A structured healthcare risk management in a hospital is no longer a ??nice to have?? but an absolutely ??must?? for the professional care of emergency patients.