越快越好—事实就是如此(摘要)

随着一次次在拥有大量听众的演讲、会议上以及许多学术杂志中谈论床旁检测实验 (ｐｏｉｎｔ ｏｆ ｃａｒｅｔｅｓｔｉｎｇ,ＰＯＣＴ) ,实验室检验人员正面对如何应用和管理ＰＯＣＴ这一问题。迄今为止 ,真正认真对ＰＯＣＴ的价值做了严肃研究的文献仍属凤毛麟角。Ｎｉｃｈｏｌｓ等发表的文章论述了应用ＰＯＣＴ如何使心血管病人等候的时间缩短。这提供了应用ＰＯＣＴ前如何缜密思考的一个例子。他们事先探讨了ＰＯＣＴ的最佳设置地点 ,如何使用ＰＯＣＴ ,如何计算测定费用 ,以及如何处理与病人的关系和工作流程 ,以使ＰＯＣＴ的应用尽可能简…     

乙肝或丙肝感染后的死亡因素:基于相关社区资料的研究

乙肝或丙肝病毒的慢性感染是肝进行性病变、肝硬化和肝癌发生的常见病因。同时感染乙肝或丙肝会进一步增加肝病恶化的危险性。乙肝或丙肝病毒感染的病史研究已得到深入的开展，尤其是在肝病病程进展的相关研究方面尤为突出，但乙肝或丙肝病毒感染后的死亡率的研究较少。大部分死亡率的研究所选择的人群具有一定的限制或者将研究限定在与自身肝病相关的死亡原因。     

Soluble kit receptor in human serum

c-kit encodes the transmembrane receptor tyrosine kinase (Kit) for the recently described ligand stem cell factor (SCF). We have developed an enzyme-linked immunosorbent assay for measuring soluble human Kit and we have used the assay to show high levels of soluble Kit in human serum. The distribution of soluble Kit levels was investigated among 112 normal human serum donors. The mean serum level (+/- SD) was found to be 324 +/- 105 ng/mL with the values falling between 163 ng/mL and 788 ng/mL. No correlation between soluble Kit levels and the sexes or ages of the donors was found. Partial purification using immunoaffinity chromatography allowed us to characterize the soluble Kit from pooled human serum. Antibodies generated to a 497-amino acid recombinant human soluble Kit corresponding to the N-terminal extracellular domain of the receptor recognized the serum-derived soluble Kit by immunoblotting. We found that the serum-derived soluble Kit is glycosylated, with mostly N- linked but also O-linked carbohydrate, and with terminal sialic acid residues. When compared with the recombinant human soluble Kit, the serum-derived material was similar both in size and glycosylation pattern. CNBr cleavage of the isolated serum-derived material followed by amino terminal sequencing confirmed the presence of five peptides expected for the extracellular portion of the Kit molecule. The immunoaffinity purified serum-derived soluble Kit inhibited binding of [125I]SCF to membrane-bound receptor in an in vitro assay. These results indicate that soluble Kit could modulate the activity and functions of SCF in vivo.     

Reduced tocopherol content of B cells from patients with chronic lymphocytic leukemia

The tocopherol content of lymphocytes, erythrocytes, and plasma from patients with chronic lymphocytic leukemia (CLL), hairy cell leukemia (HCL), and normal subjects was measured by a sensitive high performance liquid chromatographic method. Lymphocytes from patients with CLL had lower values of tocopherol (1.7 +/- 1.0 micrograms/10(9) cells) than lymphocytes from normal subjects (3.8 +/- 0.7 micrograms/10(9) cells). Mononuclear cells from patients with HCL had an increased tocopherol content of 6.2 +/- 1.0 micrograms/10(9) cells. Subfractionation of the lymphocytes from patients with CLL into T- and B-cell subgroups showed that the tocopherol content of T cells was the same as in normal subjects (4.1 +/- 0.5 micrograms/10(9) cells versus 3.5 +/- 1.2), but that the tocopherol content of the B cells was markedly reduced compared to normals (2.6 +/- 1.0 versus 6.0 +/- 1.3).     

The role of hypoxia in the maintenance of hematopoietic stem cells

Bone marrow cell liquid cultures were incubated at various oxygen concentrations ranging from 0% to 18% (air). The total number of cells in culture (CT) at the end of a 6-day incubation was found to be directly proportional to the oxygen concentration. As compared with air- incubated controls, cells recovered from severely hypoxic (1% oxygen) day-5 liquid cultures showed (1) the same day-7 colony-formation efficiency in semisolid culture (neutrophilic/monocytic colonies) or in spleen; (2) a higher day-14 spleen colony-formation efficiency; (3) an enhanced radio-protection ability; and (4) an increased marrow repopulation ability, as measured by determining either total cell number in recipient marrow MRAcell, or the capacity of the latter of generating day-7 neutrophilic/monocytic colonies in secondary in vitro assays (MRACFU-NM). Taking into account CT, the absolute numbers of progenitors in culture were also computed. The results showed that, with respect to time 0, incubation in air produced an increase in the number of day-7 CFUs and a decrease in the number of the other progenitors, whereas in hypoxic cultures all types of progenitors decreased. However, as compared with air-incubated controls, all progenitors, except cells sustaining MRACFU-NM, were reduced in hypoxic cultures. The degree of reduction paralleled the position of the progenitor in the hematopoietic hierarchy, being maximum for day-7 CFUs and null for cells sustaining MRACFU-NM, which, in fact, were better preserved in hypoxic cultures.