Triflavin, an Arg-Gly-Asp containing snake venom peptide, inhibits aggregation of human platelets induced by human hepatoma cell line

Triflavin, an Arg-Gly-Asp (RGD)-containing peptide, purified from snake venom of Trimeresurus flavoviridis, inhibits human platelet aggregation through the blockade of fibrinogen binding to fibrinogen receptors associated with glycoprotein IIb/IIIa complex. In this report, we examined the effect of triflavin on tumor cells (human hepatoma J-5)-induced platelet aggregation (TCIPA) of heparinized platelet-rich plasma (PRP). ADP-scavenger agents, apyrase (10 U/ml) and creatine phosphate (5 mM)/creatine phosphokinase (5 U/ml) did not inhibit TCIPA while hirudin (5u/ml) completely inhibited it. J-5 cells initially induced platelet aggregation, then blood coagulation occurred. J-5 cells concentration-dependently shortened the recalcification time of normal as well as Factor VIII, IX-deficient human plasmas, while it was inactive at shortening the recalcification time of Factor VII-deficient plasma, suggesting J-5 cells induced platelet aggregation through activation of extrinsic pathway, leading to thrombin formation as evidenced by the amidolytic activity on S-2238 by expressing tissue factor-like activity. Triflavin inhibited TCIPA in a dose-dependent manner (IC₅₀, 0.02 μM). When compared on molar ratio, triflavin was approximately 30,000 times more potent than GRGDS (IC₅₀,0.58 mM). On the other hand, GRGES showed no significant effect on TCIPA, even its concentration was raised to 4 mM. Additionally, the monoclonal antibodies, raised against glycoprotein IIb/IIIa complex (i.e., 7E₃ and 10 E₅) inhibited J-5 TCIPA. In conclusion, we suggest the inhibitory effect of triflavin on J-5 TCIPA may be chiefly mediated by the binding of triflavin to the fibrinogen receptor associated with glycoprotein IIb/IIIa complex on platelet surface membrane.     

A VIP antagonist distinguishes VIP receptors on spinal cord cells and lymphocytes

Vasoactive intestinal peptide (VIP) is a neuropeptide which also interacts with cells of the immune system. The paucity of specific VIP receptor antagonists has hampered studies of possible receptor heterogeneity and of VIP function. To aid in achieving these goals, a new VIP antagonist, a hybrid between neurotensin and VIP, has been synthesized. This peptide interacted with VIP receptors on spinal cord cells with an affinity 10-fold greater than VIP itself. In contrast, 1000-fold higher concentrations of the antagonist were required to displace labeled VIP from its receptor on lymphoid cells as compared to VIP itself, suggesting VIP receptor heterogeneity between immune and spinal cord cells.     

Randomized placebo-controlled trial comparing montelukast and cetirizine for treating perennial allergic rhinitis in children aged 2–6 yr

Leukotriene receptor antagonists (LTRAs) were recently added to the method of treating allergic rhinitis (AR). However, in children under 6 yr old, there has been no study about its efficacy in treating AR. We aim to compare the clinical efficacy of montelukast, cetirizine and placebo in the treatment of children from 2 to 6 yr old with perennial allergic rhinitis (PAR), to see if there are any significant differences. Sixty children were selected and treated with montelukast, or cetirizine, or placebo once daily. The efficacy of the three agents was compared with the Pediatric Rhinoconjunctivitis Quality of Life Questionnaire (PRQLQ) and Total Symptom Score (TSS) by diary. In addition, we also examined serum IgE, serum eosinophil cationic protein (ECP), blood eosinophil counts, nasal airway resistance (NAR) and eosinophil percentage in nasal smears. The results revealed that both montelukast and cetirizine were significantly efficacious compared with placebo in NAR, eosinophil percentage in nasal smears, PRQLQ, TSS and all symptom items except nasal itching, throat itching and tearing. For nasal itching, only cetirizine was significantly efficacious. On the other hand, for night sleep quality, montelukast was significantly superior to cetirizine.     

急性等容性血液稀释对血浆ET和CGRP水平的影响

目的　探讨急性等容性血液稀释 (ANH)对血浆内皮素 (ET)和降钙基因相关肽(CGRP)水平的影响。方法　选择非心脏手术ASAⅠ～Ⅱ级患者 2 0例 ,麻醉前快速输入复方乳酸钠1 0～ 1 5ml/kg。麻醉后从桡动脉放血 1 0ml/kg ,同时经静脉输入等量的 4 %琥珀酰明胶。观察ANH麻醉前 (T0 )、血液稀释完成后 1 0min(T1 )、2 0min(T2 )、30min(T3 )的血液动力学、血浆ET和CGRP浓度的变化。结果　ANH前后MAP、HR、SpO2 和ECG均较稳定。ANH后 1 0min、2 0min血浆ET水平分别为 (1 4 4 4 7± 1 9 1 7) pg/ml和 (1 5 7 1 7± 1 2 4 5 ) pg/ml,但明显高于ANH前的 (1 2 7 6 8±2 0 92 ) pg/ml(P <0 0 5 )。ANH后 1 0min、2 0min血浆CGRP水平分别为 (5 4 72± 2 5 6 5 )pg/ml和(5 5 32± 1 7 94 )pg/ml,也明显高于ANH前的 (4 4 6 2± 1 6 90 ) pg/ml(P <0 0 5 )。而ET/CGRP比值无明显变化。结论　ANH近期血浆ET和CGRP水平均有一定的增加 ,但ET/CGRP比值的变化无统计学意义 ,同时心血管反应不明显 ,表明血浆ET和CGRP的动态平衡对ANH时的循环稳定起着重要的作用     

Growth inhibition of estrogen independent MXT mouse mammary carcinomas in mice treated with an agonist or antagonist of LH-RH,an analog of somatostatin,or a combination

Summary Female BDF₁ mice inoculated with MXT (3.2) estrogen independent mouse mammary carcinoma were treated for three weeks with microcapsules of the luteinizing hormone-releasing hormone (LH-RH) agonist [D-Trp⁶]LH-RH, the antagonist SB-75, the somatostatin analog RC-160, or combinations. The lack of estrogen dependence of the tumor was proved by bilateral surgical ovariectomy, which had no effect. In two experiments, treatment with 25µg/day doses of each analog alone resulted in a significant inhibition of tumor growth as shown by a 40–53% inhibition of tumor volumes, 38–43% decrease in tumor weights, and histological signs of tumor regression. However, the combination of SB-75 or [D-Trp⁶]LH-RH with somatostatin analog RC-160 caused greater reduction of tumor volume (68 and 61%) or tumor weights (59 and 56%), than single analogs, and histologically the occurrence of apoptosis and decrease in AgNOR numbers was more pronounced in the groups receiving combination therapy. Specific binding sites for [D-Trp⁶]LH-RH, EGF, and IGF-I were demonstrated in the tumor membranes. The binding capacity of LH-RH receptors was decreased by treatment with the analogs, the greatest down-regulation being caused by combination therapy. A significant decrease in EGF binding capacity was observed after treatment with the LH-RH analogs, alone or especially in combination with somatostatin analog RC-160. The combination of these analogs also caused a reduction in IGF-I receptors. The finding that LH-RH agonists and antagonists and somatostatin analogs inhibit the growth of estrogen independent mammary tumors, and that combinations are more effective than single analogs, might be of practical importance in human breast cancer therapy.     

急性胰腺炎大鼠血浆内皮素和一氧化氮水平变化及卡托普利的早期干预作用

目的 观察急性胰腺炎大鼠血浆内皮素、一氧化氮水平变化及血管紧张素转换酶抑制剂卡托普利对其的早期干预作用。方法 63只SD大鼠分对照组、急性胰腺炎组、卡托普利干预组3组进行不同处理。对照组仅作胃窦切开再缝合术；急性胰腺炎组用十二指肠闭襻法制作急性胰腺炎模型；卡托普利干预组在胰腺炎模型制备后立即腹腔注射卡托普利针(5mg／kg)，在病程不同时点测定血浆内皮素、一氧化氮水平，并观察胰腺组织病理学改变。结果 急性胰腺炎组随病变的进展，胰腺炎病理由水肿向出血坏死发展，而内皮素和一氧化氮从两者平行升高逐渐转向内皮素单一升高，致内皮素／一氧化氮比值上升；卡托普利干预组则胰腺炎病理改变减轻，胰腺组织病理学评分降低，且血浆内皮素水平低于急性胰腺炎组，而一氧化氮总体水平与急性胰腺炎组比较差别无显著性意义，内皮素／一氧化氮比值基本与对照组一致。结论 早期应用卡托普利可维持内皮素与一氧化氮平衡，对大鼠急性胰腺炎病变可能有保护作用。     

内皮素在评价不阻断升主动脉低温室颤对心肌保护作用中的应用

①目的探讨体外循环条件下低温室颤技术对心肌的保护作用。②方法14只健康成年犬随机分为两组，低温停跳组(n=7)与低温室颤组(n=7)，分别检测两组手术前、手术1、2小时和复跳后1小时4个时间点血内皮素(ET)的水平。③结果室颤组ET水平明显低于停跳组。④结论通过内皮素水平的变化，说明体外循环条件下低温室颤技术是一种安全、有效的心肌保护方式，优于传统低温停跳技术。     

Characterization of high-affinity receptors for bombesin/gastrin releasing peptide on the human prostate cancer cell lines PC-3 and DU-145: Internalization of receptor bound 125I-(Tyr4) bombesin by tumor cells

Specific receptors for bombesin/gastrin releasing peptide (GRP) on the androgen-independent human prostate cancer cell lines PC-3 and DU-145 were characterized. No specific binding of ¹²⁵I-[Tyr⁴]-bombesin to the androgen-dependent human prostate cancer cell line LNCaP was detectable. The binding of ¹²⁵I-[Tyr⁴]-bombesin to PC-3 and DU-145 cells was found to be time- and temperature-dependent, saturable, and reversible. Scatchard analysis revealed a single class of binding sites with high affinity (K_d 9.8 × 10^?11 M for PC-3, and 9.1 × 10-¹¹ M for DU-145 cells at 25°C) and with a binding capacity of 44,000 binding sites/cell and 19,000 binding sites/cell, respectively. Bound ¹²⁵I-[Tyr⁴]-bombesin was rapidly internalized by PC-3 cells. The nonhydrolyzable GTP analog GTP-gamma-S caused a dose-dependent inhibition of ¹²⁵I-[Tyr⁴]-bombesin binding to PC-3 and DU-145 cells, indicating that a G-protein (guanine nucleotide-binding protein) couples the bombesin receptor to intracellular effector systems. Bombesin and GRP(14-27) inhibited the binding of ¹²⁵I-[Tyr⁴]-bombesin to both cell lines in a dose-dependent manner with inhibition constants (K_i of 0.5 nM and 0.4 nM, respectively. Both cell lines express the bombesin/GRP preferring bombesin receptor subtype, since, in displacement studies, neuromedin B was more than 200 times less potent than bombesin and GRP(14-27) in inhibiting the binding of ¹²⁵I-[Tyr⁴]-bombesin. Two synthetic bombesin/GRP antagonists, RC-3095 and RC-3110, powerfully inhibited the specific binding of ¹²⁵I-[Tyr⁴]-bombesin with K_i 0.92 nM and 0.26 nM on PC-3 cells, and 3.3 nM and 0.89 nM on DU-145 cells, respectively. These findings indicate that the PC-3 and DU-145 human prostate cancer cell lines possess specific high-affinity receptors for bombesin/GRP, and are suitable models for the evaluation of the antineoplastic activity of new bombesin/GRP antagonists in the treatment of androgen-independent prostate cancer. © 1994 Wiley-Liss, Inc.     

Effect of a single dose of the selectin inhibitor TBC1269 on early and late asthmatic responses

BACKGROUND : Selectins participate in the initial phase of leucocyte migration from circulation to inflamed tissues and may play a role in inflammatory cellular influx into airways in asthma. In the sheep asthma model, TBC1269, a pan-selectin antagonist, reduced late allergen response by 74%. OBJECTIVE : To determine whether a single dose of TBC1269 inhibits early (EAR) and late (LAR) asthmatic responses, and whether it inhibits sputum leucocyte influx after inhalation allergen challenge in atopic asthmatic subjects treated with bronchodilators only. METHODS : Twenty-one asthmatic subjects (mean+/-SD, age=32.5+/-6.7 years, 8 males, FEV1 percent predicted=84+/-15%) with known late asthmatic response based on a screening inhalation allergen challenge were randomly assigned to receive intravenous treatment with either placebo (n=11) or TBC1269 (n=10, 30 mg/kg) infused over 15 min immediately prior to a second (post-treatment) allergen challenge at least 4 weeks after the screening challenge. After each challenge, EAR and LAR were monitored for 7 h. In addition, sputum was induced 1 day before and 1 day after each allergen challenge. RESULTS : TBC1269 did not attenuate the EAR compared with placebo (largest fall in FEV1 within 1 h of 34.1+/-13.9% vs. 31.8+/-12.2% for TBC1269 and placebo groups respectively, P=0.61) or the LAR (largest fall in FEV1 between 3 and 7 h of 39.3+/-15.3% vs. 32.6+/-13.8%, P=0.24). TBC1269 had only minor effects on allergen-induced sputum eosinophilia. CONCLUSION : We conclude that TBC1269 administered before allergen challenge as a single intravenous dose does not attenuate early or late asthmatic responses to allergen in asthmatic subjects.