下坡运动对大鼠骨骼肌肌浆网功能的影响

目的：观测研究下坡(离心)运动对大鼠骨骼肌肌浆网Ca2+-ATP酶活性,Ca2+摄取与释放在量与时程上的影响。此外,测定离子载体的刺激作用,即测定在含与不含(Ca2+离子载体)A23187时Ca2+-ATP酶活性的比值,用以评定囊泡的完整性。方法：成年雄性SD大鼠随机分为对照与离心运动组, 离心运动的大鼠分别于运动后即刻, 4, 24, 48, 72 和144h后取样 (n=7). 离心运动方式采用90min持续跑台下坡运动(-16°;15m/min)。取大鼠红股肌制备组织匀浆, 测定肌浆网Ca2+-ATP酶活性,Ca2+摄取与释放。结果：与对照组[19.25±1.38 nmol ·min-1·(mg protein)-1]相比, 肌浆网Ca2+摄取分别于运动后即刻和4h下降了29% and 36% (P<0.05), 24h依然降低(P<0.05). 肌浆网Ca2+释放与对照组[31.06±2.36 nmol·min-1·(mg protein)-1] 相比,也分别于运动后即刻和4h下降了37% and 39% (P<0.05), 24h持续降低(P<0.05). 用含离子载体测定的肌浆网Ca2+-ATP酶活性运动后4h降低了31%(P<0.05), 并于运动后24h仍然降低 (P<0.05)。运动后, 含与不含A23187时测定的Ca2+-ATP酶活性的比值未见显著性改变, 表明该运动没有明显改变肌浆网膜的完整性。结论：一次性低强度，长时间下坡运动导致肌浆网功能长时间降低, 运动后恢复期两天尚未完全恢复, 亦可构成离心运动诱导的骨骼肌某些功能降低的基础。提示这些变化可能产生于离心收缩时肌节长度不匀一性所造成的张力应激。     

Application of biosafety principles in blood establishments

In light of increasing public and employee concern over potential infectious hazards associated with blood and other body fluids, several government agencies (the Food and Drug Administration, the Centers for Disease Control, the Occupational Safety and Health Administration, the Environmental Protection Agency, the Health Care Financing Administration and the National Heart, Lung and Blood Institute) cosponsored a Biosafety Workshop in April 1988. The objective of the workshop was to identify appropriate biosafety practices and standard control procedures to protect workers involved in the collection, storage, and transportation of human blood donations with the least possible disruption of the nation's blood supply. Speakers focused on human immunodeficiency virus (HIV) and hepatitis B virus (HBV); however, the safety principles discussed were considered equally applicable to other known (e.g., non-A, non-B hepatitis and human T-lymphotropic virus type I (HTLV-1) blood-transmitted infections. The resulting consensus included the need for blood establishments to develop and apply thoughtful biosafety programs to address staff training, accident prevention, HBV vaccination, handling spills, managing contaminated waste and transporting blood specimens. There was lack of agreement, however, on the usefulness of gloves during the phlebotomy of healthy blood donors.     

In vitro changes in platelet function and metabolism following increasing doses of ultraviolet-B irradiation

Ultraviolet-B (UV-B) irradiation of platelet concentrates (PCs) may prevent the development of posttransfusion HLA alloimmunization. This study evaluated the effect of increasing doses of UV-B radiation on stored PCs. Pooled PCs were irradiated at UV-B doses of 600, 2400 or 10,000 mJ per cm2 and stored up to 96 hours under standard blood bank conditions. Compared to nonirradiated room-temperature and 37 degrees C controls, the irradiated units showed no significant changes in platelet count, white cell count, discharge of lactate dehydrogenase, release of beta-thromboglobulin, metabolism of ATP, ADP, ammonia, glutamine, glutamate, hypoxanthine, pCO2, or pO2 at any time of storage following any of the three UV-B doses. However, after a dose of 10,000 mJ per cm2, there were significant decreases in in vitro assays of platelet function-specifically, osmotic recovery and morphology score. Some metabolic systems were also affected by the 10,000 mJ per cm2 radiation dose, as shown by a decline in pH and bicarbonate and an increase in glucose consumption and lactate production (p < 0.05). The changes in these latter assays appeared only after 96 hours of postirradiation storage. Such changes were not seen in either the room- temperature or 37 degrees C control groups. Thus, heat generated during irradiation, per se, did not appear responsible for the observed in vitro changes in platelet function and metabolism. On the basis of the assays analyzed, it is concluded that UV-B irradiation of PCs at doses up to 10,000 mJ per cm2 does not induce significant metabolic or functional derangements following short-term storage (24-48 hours).(ABSTRACT TRUNCATED AT 250 WORDS)     

Specificity of cytotoxic effector cells directed against trinitrobenzene sulfonate-modified syngeneic cells. Failure to recognize cell surface- bound trinitrophenyl dextran

Mouse splenic lymphocytes and lymphoid tumor cells were modified with the trinitrophenyl (TNP) group either by treatment with trinitrobenzene sulfonate (TNBS) (which covalently modifies cell surface proteins) or with TNP stearoyl dextran (TSD) (which binds to the cell by noncovalent forces). These cell preparations were compared for their ability to: (a) sensitive syngeneic splenic lymphocytes leading to the generation of cytotoxic effector cells; (b) serve as lysable targets in a 4-h(51)Cr- release assay for effector cells generated in (a); and (c) act as blocking cells in the lysis of TNBS-medified targets lysed by TNP self effector cells generated in (a). In none of these three experimental systems did TSD-medified syngeneic spleen or H-2-matched tumor cells act either as a sensitizing immunogen or as a target antigen, despite the demonstration that quantitatively equivalent mounts of TNP were exposed on the cell surface in the TNBS- and TSD-modified cells. In contrast, TNBS-modified spleen cells sensitized syngeneic lymphocytes to generate effectors against TNBS-modified syageneic targets. Furthermore, TNBS- modified, H-2-matched cells served as specific lysable targets and as inhibiting cells for such effectors. These results indicate that the manner in which TNP is associated with the cell surface is important in the immunogenicity and antigenicity of hapten-modified syngeneic stimulating cells in generating H-2-associated cell-mediated lympholysis (CML) reactions. These findings raise the possibility that a covalent or at least a stable linkage with cell surface proteins (possibly H-2- controlled products) is important for immunological function. Furthermore, these observations do not favor the dual receptor model for H-2-restricted syngeneic CML if it is assumed in such a model that one receptor is specific for the TNP moiety and the second for unmodified self major histocompatibility products.     

Inflammatory bowel disease and the X chromosome

A review of documented cases demonstrates a significant association of Turner's syndrome with Crohn's disease and ulcerative colitis; this association relates particularly to genetic constitutions comprising an abnormal rather than an absent X chromosome. The karyotype 46XiXq, in pure or mosaic form, appears to be a significant susceptibility factor for inflammatory bowel disease. This karyotype often gives rise to relatively weak phenotypic characteristics of Turner's syndrome, which may be overlooked in short females with inflammatory bowel disease. The association of inflammatory bowel disease with Turner's syndrome may reflect the presence on the X chromosome of genes involved in disease pathogenesis. Linkage analysis studies, involving microsatellite markers on the X chromosome, are being performed.      

Expression and function of receptors for stem cell factor and erythropoietin during lineage commitment of human hematopoietic progenitor cells

The aim of the present study was to determine whether stem cell factor (SCF) and erythropoietin (EPO) act differently on defined subsets of progenitor cells, and if potential differences correlate with the receptor density on each subset. To investigate this possibility directly, we optimized conditions for the identification and purification of homogeneous progenitor cell subpopulations from human bone marrow. Populations containing 40% and 44% colony forming cells (CFCs) with 99% and 95% purity for the granulomonocytic and erythroid lineage, respectively, were sorted on the basis of differential expression of CD34, CD64, and CD71. In addition, a population containing 67% CFCs, of which 29-43% were CFU-MIX, was sorted from CD34hi CD38loCD50+ cells. Purified progenitor cell subsets were compared directly for responsiveness to SCF and EPO using a short-term proliferation assay. Expression of the receptors for SCF and EPO were then examined on each subset using a flow cytometer modified for high- sensitivity fluorescence measurements. The results show that EPO induces extensive proliferation of erythroid progenitor cells, but has no effect on the proliferation or survival of primitive or granulomonocytic progenitors, even when used in combination with other cytokines. The majority of erythroid progenitor cells furthermore stained positively with anti-EPO receptor (EPO-R) monoclonal antibodies, whereas other progenitor cells were negative. SCF alone induced extensive proliferation of erythroid progenitor cells, and had a stronger synergistic effect on primitive than on granulo-monocytic progenitors. In spite of these differences in SCF activity, there were no significant differences in SCF-R expression between the progenitor subsets. These results suggest that the selective action of EPO on erythropoiesis is determined by lineage-restricted receptor expression, whereas there are additional cell-type specific factors that influence progenitor cell responses to SCF.     

In vitro characteristics of volume-reduced platelet concentrate stored in syringes

For convenience, small volumes of platelet concentrate (PC) intended for neonatal patients are often dispensed in syringes. The PC, however, may remain in the syringe for up to several hours before the actual transfusion. As there are few data on the effect of such syringe storage on PCs, the in vitro syringe storage properties of small volumes of 1- and 5-day-old units, and volume-reduced units of PC were evaluated. In four separate experiments, PCs were stored in syringes in volumes of 10, 15, or 30 mL for up to 6 hours at 20 to 24 degrees C without agitation. Platelets were evaluated for pH, platelet count, and a variety of biochemical and in vitro functional assays. Results showed that even with the equivalent of a full unit of platelets stored in the syringe for up to 6 hours, the pH did not fall below 6.0. Although there was an increase in lactate production and consumption of glucose, which paralleled the decline in pH, the changes were not greater than those seen in platelets stored up to 5 days in gas-permeable blood bags. Similar results were seen for PCs stored in syringes for 6 hours at 37 degrees C. All of the pH levels recorded at the end of 6 hours of syringe storage were above the minimum required level of pH 6.0. Data from in vitro platelet assays imply that at any time during their shelf life, PCs can be stored in gas-impermeable polypropylene syringes for up to 6 hours and can maintain acceptable storage characteristics; in vivo data are needed to confirm these observations.     

锡伯族和汉族冠心病患者颈动脉粥样硬化及冠状动脉病变对比分析

目的 对比分析锡伯族、汉族冠心病患者颈动脉粥样硬化及冠状动脉病变情况.方法 对经冠状动脉造影明确的48例锡伯族、57例汉族冠心病患者和50例正常对照者均行颈动脉超声检查,比较各组间颈动脉内膜中膜厚度、斑块的发生率及冠状动脉病变的Gensini积分.结果 锡伯族、汉族冠心病患者内膜中膜厚度及颈动脉斑块的发生率均高于正常对照者(1.1±0.3 mm和1.0±0.1 mm比0.6±0.2 mm、88.3%和77.2%比38.0%,P<0.05),但锡伯族与汉族间比较没有统计学差异(P>0.05);锡伯族患者冠状动脉病变支数少于汉族(1.82±0.24比2.54±0.31, P<0.05),冠状动脉病变的Gensini积分也明显低于汉族(8.23±1.35比15.84±2.68,P<0.05),且冠状动脉病变支数越多,锡伯族、汉族冠心病患者颈动脉粥样硬化程度越重.结论 锡伯族和汉族冠心病患者颈动脉粥样硬化情况均重于正常对照者,但锡伯族和汉族间比较没有统计学意义;锡伯族和汉族冠心病患者冠状动脉病变存在差异,且锡伯族冠心病患者冠状动脉病变严重程度低于汉族;通过颈动脉内膜中膜厚度的程度可预测冠状动脉病变的存在及严重程度.