Study on the Mechanism of the Annexin I -Mediated Co-Assembly of t-PA and Plasminogen

In order to further investigate the effect of annexin Ⅱ (Ann- Ⅱ ) on tissue plasminogen activator (t-PA)-dependent plasminogen (PLG) activation and its interactive mechanism, recombinant native Ann- Ⅱ bound t-PA, PLG and plasmin with high affinity was examined. The flow cytometric assay showed that the ann- Ⅱ expression rate was higher in the human umbilical vein endothelial cell (HUVEC) (87. 65 %) than in the HL-60 cells as controls (35. 79 %). Two irrelevant proteins,bovine serum albumin (BSA) and equine IgG (EIG) had no effect on the production of plasmin.Ann- Ⅱ -mediated enhancement of t-PA-dependent PLG activation was inhibited by ε-aminocaproic acid or by pretreatment of Ann- Ⅱ with carboxypeptidase B with the inhibitive rate being 77.8 % and 77. 0 %, respectively. It was revealed that the effect of Ann- Ⅱ on PLG activation was specific for tPA. Urokinase didn‘t bind to Ann- Ⅱ , demonstrating the role of receptor-related lysine residues on activation of PLG, showing that the Ann- Ⅱ -PLG interaction was dependent upon carboxyl-terminal lysine residues. These findings suggest that annexin Ⅱ -mediated co-assembly of t-PA and PLG may promote plasmin generation and play a key role in modulating fibrinolysis on the endothelial surface.     

Muscular activation patterns of healthy persons and low back pain patients performing a functional capacity evaluation test

The results of most reported studies show differences between the muscular activity of low back pain patients and healthy subjects, but the focus has usually been on trunk muscles only, and they have not involved work-related tests or exercises. The reintegration of chronic low back pain patients to job market is a common problem. Therefore assessment systems like the functional capacity evaluation (FCE) according to Isernhagen [S.J. Isernhagen, Work Injury: Management and Prevention, Aspen Publishers Inc., Gaithersburg, MD, 1988] are often used tools to determine the physical abilities and deficits of long-time incapacitated persons. The aim of the present study was to compare the healthy persons and chronic low back pain patients in performing a FCE-test and to analyse their muscular activation and motion patterns. The results indicate differences in the activation patterns of the groups in the test task “floor to waist lift” common in many occupations.     

Changes in Neutrophil Oxidative Potential in Patients Undergoing Cardiopulmonary Bypass with Polypropylene Hollow Fiber Oxygenators

Neutrophil oxidative metabolism, C3d and beta 2 microglobulin levels, were assessed in nine consecutive patients undergoing cardiopulmonary bypass surgery with polypropylene hollow fiber oxygenators for open cardiac operations. Generation of oxygen free radicals by neutrophils was measured as luminol-enhanced chemiluminescence after stimulation with opsonized Zymosan and phorbol myristate acetate. A significant increase in light emission was detected by using both of the chemiluminescence stimulators. Moreover, a remarkable and significant increase in C3d levels was found already at 10 min. Conversely minimal changes in levels of beta 2 microglobulin were detected during cardiopulmonary bypass surgery. These data suggest that the impact of the patient blood with the foreign surface of cardiopulmonary bypass results in activation of phagocyte cells with increased potential in oxygen consumption. These effects could be partially complement-mediated.     

Effects of accumbens DALA microinjections on brain stimulation reward and behavioral activation in intact and 6-OHDA treated rats

The effects of bilateral nucleus accumbens microinjections ofd-ala-met-enkephalinamide (DALA) were assessed in behavioral activation and lateral hypothalamic self-stimulation (LHSS) rate-frequency curve-shift paradigms in normal and accumbens 6-OHDA (4.0 µg) treated rats. Microinjections of DALA (2.5 µg/µl) in the behavioral activation paradigm had little effect on normal activity; however, DALA administered to 6-OHDA treated rats produced a significant overall increase in locomotion. The 6-OHDA DALA-induced locomotion effect peaked at 2 weeks after 6-OHDA treatment and then returned to baseline levels by week 5 posttreatment. Using LHSS, DALA tested over a range of doses (2.5, 5, 10, 20 µg/µl) displayed a weak biphasic reward effect only at the highest dose, which was characterized by an initial suppression followed by an elevation. DALA significantly depressed initial operant motor/performance in LHSS in a dose dependent fashion. Micro-injections of the normally ineffective low dose of DALA (2.5 µg/µl) following accumbens 6-OHDA treatment produced a significant LHSS reward decrease 2 weeks posttreatment, while LHSS motor/performance was relatively unaffected. Results are discussed in terms of opiate-dopamine and limbic-motor interactions.     

用稳定性同位素~(58)Fe中子活化法测定缺铁性贫血儿童膳食铁吸收率

本文报告了应用稳定性同位素~(58)Fe对三组缺铁性贫血儿童,分别摄取平衡膳、平衡膳加大豆蛋白膳和平衡膳加大豆蛋白加维生素C膳时,各组儿童膳食铁的吸收率。测定结果顺次分别为12.0±3.6％、10.7±4.7％和18.1±3.6％。后者高于前二者,差异显著。据此,作者同意国际营养性贫血咨询小组(INACG)以及大多数学者的主张,即大豆制品不利于或降低膳食铁的生物利用率(bioavailability)。本文并结合实验讨论了本法的原理、操作技术及误差控制等问题,评价了本法在类似工作中的重要意义。     

Study on lymphocyte activation and proliferation induced by anti-CD3 McAb

Summary T cell activation and proliferation via CD₃-TCR complex were investigated by lymphocyte DNA synthesis in vitro. Several interfering factors were also discussed. The result indicated that lymphocyte activation and proliferation are calciumdependent. A rise of cytoplasmic free Ca²⁺ quickly following activation with CD₃ McAb is mainly due to intracellular mobilization of Ca²⁺, while lymphocyte proliferation needs both intracellular mobilization of Ca²⁺ as well as influx of extracellular Ca²⁺. It was confirmed that CTX sensitive G protein plays a role in regulating T cell proliferation by pretreatment with CTX suppressing lymphocyte³H-TdR incorporation obviously. PLC and PKC inhibitor neomycin and P. S. S could also decrease T cell proliferation.     

Mutagenicity of benzo(a)pyrenyl-1-sulfate in the Ames test.

Comparison of the mutagenicity of nine isomeric benzo(a)pyrenyl [B(a)P] phenols conjugated with either sulfate or glucuronide was carried out using strain Salmonella typhimurium TA98. Of the nine conjugates tested, only B(a)P-1-sulfate was mutagenic. Accordingly, the mutagenicity of B(a)P-1-sulfate was compared with that of B(a)P and 1-hydroxybenzo(a)pyrene [B(a)P-1-OH] in the presence and absence of rat lung S9 and Aroclor-induced liver S9 with and without an NADPH-generating system. B(a)P-1-sulfate was slightly mutagenic, whereas B(a)P and the 1-hydroxy derivative were nonmutagenic when S9 fractions and NADPH were omitted. Addition of induced liver S9 with NADPH caused mutagenicity with B(a) -1-OH greater than B(a)P greater than B(a)P-1-sulfate. B(a)P-1-sulfate was the only mutagenic species when lung S9 was added. This mutagenicity did not require NADPH. Sodium sulfite, an inhibitor of arylsulfatase, decreased the mutagenicity of B(a)P-1-sulfate. These data suggest that a unique mutagenic species is generated from B(a)P-1-sulfate via arylsulfatase in rat lung.     

The assembly of the factor X-activating complex on activated human platelets

Summary.  Platelet membranes provide procoagulant surfaces for the assembly and expression of the factor X-activating complex and promote the proteolytic activation and assembly of the prothrombinase complex resulting in normal hemostasis. Recent studies from our laboratory and others indicate that platelets possess specific, high-affinity, saturable, receptors for factors XI, XIa, IX, IXa, X, VIII, VIIIa, V, Va and Xa, prothrombin, and thrombin. Studies described in this review support the hypothesis that the factor X-activating complex on the platelet surface consists of three receptors (for the enzyme, factor IXa; the substrate, factor X; and the cofactor, factor VIIIa), the colocalization of which results in a 24 million-fold acceleration of the rate of factor X activation. Whether the procoagulant surface of platelets is defined exclusively by procoagulant phospholipids, or whether specific protein receptors exist for the coagulant factors and proteases, is currently unresolved. The interaction between coagulation proteins and platelets is critical to the maintenance of normal hemostasis and is pathogenetically important in human disease.