Pharmacology of KB‐R7943: A Na+–Ca2+ exchange inhibitor

The Na⁺–Ca²⁺ exchange (NCX) system plays a pivotal role in regulating intracellular Ca²⁺ concentration in cardiomyocytes, neuronal cells, kidney and a variety of other cells. It performs a particularly important function in regulating cardiac contractility and electrical activity. One of the leading NCX inhibitors is KB‐R9743 (KBR) that appears to exhibit selectivity for Ca²⁺‐influx‐mode NCX activity (reverse mode of NCX). In this article we reviewed pharmacology of KBR and provide a brief summary of studies with other NCX inhibitors, such as SEA0400 (SEA) and SN‐6 (SN). Potential clinical usefulness of KBR and other NCX inhibitors is still controversial but the reviewed findings may be helpful in designing more selective and clinically useful NCX inhibitors for the treatment of cardiac, neuronal and kidney diseases.     

Immunolocalization of intercellular adhesion molecule-1 and leukocyte functional associated antigen-1 in schistosomal soluble egg antigen-induced granulomatous hyporesponsiveness

In this work, the changes in expression of the adhesion molecules ICAM-1/LFA-1 on inflammatory cells of the liver were studied by immunohistochemistry. Mice sensitized with SEA and infected with S. mansoni and S. mansoni-infected controls were examined from day 35 to day 56 postinfection. A significant upregulation of ICAM-1 and LFA-1 in both the SEA group and the infected control group started shortly after egg deposition at day 35 and persisted up to day 56 p.i. Notably, both ICAM-1 and LFA-1 expression peaks were shifted earlier to day 38 p.i. in the SEA group compared to day 40 in the infected control group. The distribution of ICAM-1 and LFA-1 in both groups was comparable. At the early phase of infection before granuloma formation, both ICAM-1 and LFA-1 were detected along the sinusoidal wall of small blood vessels. At the acute cellular granuloma phase, they were homogeneously distributed all over the inflammatory cells, while at the chronic fibrocellular stage a non-homogeneous staining of granuloma cells at the periphery of the granuloma was apparent. The present data suggest that adhesion molecules play a role in the initiation and maintenance of granuloma formation. Thus, the granulomatous hyporesponsiveness induced by sensitization with SEA was associated with reduced expression of adhesion molecules.     

Evaluation of T and B lymphocyte function in clinical practice using a flow cytometry based proliferation assay

The golden standard for functional evaluation of immunodeficiencies is the incorporation of [³H]-thymidine in a proliferation assay stimulated with mitogens. Recently developed whole blood proliferation assays have the advantage of parallel lymphocyte lineage analysis and in addition provide a non-radioactive alternative. Here we evaluate the Flow-cytometric Assay for Specific Cell-mediated Immune-response in Activated whole blood (FASCIA) in a comparison with [³H]-thymidine incorporation in four patients with severe combined immunodeficiency. The threshold for the minimum number of lymphocytes required for reliable responses in FASCIA is determined together with reference values from 100 healthy donors when stimulated with mitogens as well as antigen specific stimuli. Finally, responses against PWM and SEA + SEB stimuli are conducted with clinically relevant immunomodulatory compounds. We conclude that FASCIA is a rapid, stable and sensitive functional whole blood assay that requires small amounts of whole blood that can be used for reliable assessment of lymphocyte reactivity in patients.     

穿心莲超分子提取物的抗炎作用机制研究

目的:研究穿心莲超分子提取物(SEA)的抗炎作用机制。方法:采用蛋清致炎模型测定炎症渗出液中丙二醛(MDA)含量和血清中SOD,CAT活力;醋酸所致小鼠腹腔炎症测定渗出液中PGE2的含量。结果:穿心莲超分子提取物能够显著降低炎症渗出液中PGE2和MDA含量,显著提高小鼠血清SOD和红细胞CAT活力。结论::穿心莲超分子提取物抗炎作用可能是通过抑制环氧化酶(COX)、抗自由基、抗氧化作用实现的。     

Unique excitation–contraction characteristics of mouse myocardium as revealed by SEA0400, a specific inhibitor of Na<Superscript>+</Superscript>–Ca<Superscript>2+</Superscript> exchanger

The functional role of the sodium–calcium exchanger in mouse ventricular myocardium was evaluated with a newly developed specific inhibitor, SEA0400. Contractile force and action potential configuration were measured in isolated ventricular tissue preparations, and cell shortening and Ca²⁺ transients were measured in indo-1-loaded isolated ventricular cardiomyocytes. SEA0400 increased the contractile force, cell shortening and Ca²⁺ transient amplitude, and shortened the late plateau phase of the action potential. -adrenergic stimulation by phenylephrine produced a sustained decrease in contractile force, cell shortening and Ca²⁺ transient amplitude, which were all inhibited by SEA0400. Increasing the contraction frequency resulted in a decrease in contractile force in the absence of drugs (negative staircase phenomenon). This frequency-dependent decrease was attenuated by SEA0400 and enhanced by phenylephrine. Phenylephrine increased the Ca²⁺ sensitivity of contractile proteins in isolated ventricular cardiomyocytes, while SEA0400 had no effect. These results provide the first pharmacological evidence in the mouse ventricular myocardium that inward current generated by Ca²⁺ extrusion through the sodium–calcium exchanger during the Ca²⁺ transient contributes to the action potential late plateau, that -adrenoceptor-mediated negative inotropy is produced by enhanced Ca²⁺ extrusion through the sodium–calcium exchanger, and that the negative staircase phenomenon can be explained by increased Ca²⁺ extrusion through the sodium–calcium exchanger at higher contraction frequencies.     

双调控溶瘤腺病毒介导超抗原SEA基因靶向膀胱肿瘤表达

目的 构建携带SEA基因的选择性增殖腺病毒,体外实验观察SEA基因的表达及其刺激淋巴细胞对肿瘤的杀伤功能.方法 构建一种由端粒酶(hTERT)和缺氧反应元件(HIF)双重启动的携带SEA的选择性增殖腺病毒,通过逆转录-聚合酶链反应(RT-PCR)检测SEA在肿瘤细胞内mRNA表达,免疫荧光定位SEA表达于肿瘤细胞,Western blot测定蛋白表达,显微镜下动态观测淋巴细胞与肿瘤细胞共培养.酶联免疫吸附试验(ELISA)检测白细胞介素(IL)-4分泌.结果 琼脂糖电泳252 bp处可见清晰条带;免疫荧光及Western blot用考马斯亮蓝染色显示在27 kDa附近可见蛋白清晰表达;淋巴细胞与肿瘤细胞共培养12、24、48 h实验组肿瘤细胞明显少于对照组,ELISA检测IL-4分泌量实验组均高于对照组(t=2.585 P＜0.05).结论 携带SEA基因的选择性腺病毒成功构建并表达目的基因,证明对肿瘤细胞的杀伤作用.     

Preservation of mitochondrial function may contribute to cardioprotective effects of Na+/Ca2+ exchanger inhibitors in ischaemic/reperfused rat hearts

BACKGROUND AND PURPOSE: Na+/Ca2+ exchanger (NCX) inhibitors are known to attenuate myocardial reperfusion injury. However, the exact mechanisms for the cardioprotection remain unclear. The present study was undertaken to examine the mechanism underlying the cardioprotection by NCX inhibitors against ischaemia/reperfusion injury. EXPERIMENTAL APPROACH: Isolated rat hearts were subjected to 35-min ischaemia/60-min reperfusion or 20-min ischaemia/60-min reperfusion. NCX inhibitors (3-30 microM KB-R7943 (KBR) or 0.3-1 microM SEA0400 (SEA)) were given for 5 min prior to ischaemia (pre-ischaemic treatment) or for 10 min after the onset of reperfusion (post-ischaemic treatment). KEY RESULTS: With 35-min ischaemia/60-min reperfusion, pre- or post-ischaemic treatment with KBR or SEA neither enhanced post-ischaemic contractile recovery nor attenuated ischaemia- or reperfusion-induced Na+ accumulation and damage to mitochondrial respiratory function. With the milder model (20-min ischaemia/reperfusion), pre- or post-ischaemic treatment with 10 microM KBR or 1 microM SEA significantly enhanced the post-ischaemic contractile recovery, associated with reductions in reperfusion-induced Ca2+ accumulation, damage to mitochondrial function, and decrease in myocardial high-energy phosphates. Furthermore, Na+ influx to mitochondria in vitro was enhanced by increased concentrations of NaCl. KBR (10 microM) and 1 microM SEA partially decreased the Na+ influx. CONCLUSIONS AND IMPLICATIONS: The NCX inhibitors exerted cardioprotective effects during relatively mild ischaemia. The mechanism may be attributable to prevention of mitochondrial damage, possibly mediated by attenuation of Na+ overload in cardiac mitochondria during ischaemia and/or Ca2+ overload via the reverse mode of NCX during reperfusion.     

Colonic bacterial superantigens evoke an inflammatory response and exaggerate disease in mice recovering from colitis

BACKGROUND & AIMS: There is renewed interest in commensal bacteria as triggers of idiopathic disease, a concept that is prominent in inflammatory bowel disease (IBD). Here the effect of intracolonic instillation of Staphylococcus aureus enterotoxin B (SEB), a model superantigen (SAgs: potent T-cell stimuli), into mice was examined. METHODS: Mice (Balb/c, severe combined immunodeficient [SCID], V beta 8(+) ovalbumin transgenic [OVA-Tg], interleukin 10 [IL-10] knockout [KO]) received a single intrarectal (IR) dose of SAg and colonic form (histology, myeloperoxidase [MPO] activity) and function (ion transport) were assessed 12-72 hours later. In subsequent studies the potential for SEB to reactivate disease in mice recovering from dextran sodium sulfate (DSS)-induced colitis (5 days at 4% [wt/vol] followed by 14 days normal water) was examined. RESULTS: SEB-treated Balb/c mice displayed a time- and dose-dependent colonic inflammation (increased MPO, histologic damage score, and macrophage number). Similar events occurred in response to other SAgs, namely S. aureus enterotoxin A (SEA) and Yersinia pseudotuberculosis mitogen. Ion transport, the driving force for water movement, was unaffected by SEB treatment. SCID mice developed no inflammation after IR SEB delivery, whereas OVA Tg mice displayed enhanced responsiveness. Although SEB treatment of IL-10 KO mice did elicit a response, the inflammation was transitory and did not hasten the spontaneous colitis seen in these mice. Finally, mice recovering from DSS-induced colitis showed a worsening of the disease when challenged with SEB; IR SEB evoked significant increases in MPO, macrophage infiltration, T-cell activation (i.e., CD25 expression), and perturbed epithelial ion transport. CONCLUSIONS: Lumen-derived bacterial SAgs can elicit a local inflammation and aggravate enteric inflammatory disorders in which they were not the causative agent.     

重组Sj31-b的表达及其免疫诊断价值的研究

目的 探讨日本血吸虫重组31KD蛋白片（rSJ31-b)的免疫诊断价值。方法 表达并纯化rSj31-b，用免疫印迹方法（EITB）检测纯化的rSj-b的免疫活性，以rSj31-b-ELISA分别检测慢性日本血吸虫病人及正常人的血清。结果 纯化的重组Sj31-b具有较好的免疫活性；用其rSj31-b－ELISA检测52份慢性日本血吸虫病人血清及83份正常人血清，敏感性和特异性与常规应用的天然抗原SEA（可溶性虫卵抗原）差异无显性。检测治疗12个月后的慢性日本血吸虫病人血清，阴转率85.0%，明显优于SEA－ELISA。结论 rSj31-b具有较好的敏感性和特异性，且有一定的疗效考核价值，可替代SEA用于慢性日本血吸虫病人的诊断。     

复方海蛇酊药理研究

复方海蛇酊具有祛风除湿，通络止痛的功效。本研究结果表明，复方海蛇酊具有抗炎、镇痛的药理作用。其作用主要是通过降低毛细血管通透性，抑制炎症渗出的结果，其抗炎作用机理可能是通过影响肾上腺皮质系统所致。复方海蛇酊ＬＤ５０测定结果为２６．９２ｍｌ／Ｋｇ，提示其有一定的急性毒性反应。