新的钙通道阻滞剂 MC9204 对离体兔动脉环的作用

目的：比较ＭＣ９２０４和ｎｉｆｅｄｉｐｉｎｅ（ＮＩＦ）的扩血管强度，并观察ＭＣ９２０４是否具有血管选择性作用。方法：采用离体血管张力实验法，观察ＭＣ９２０４和ＮＩＦ的扩血管作用。结果：ＭＣ９２０４和ＮＩＦ对ＫＣｌ、ＣａＣｌ２和去甲肾上腺素（ＮＥ）引起的离体兔动脉环收缩反应均具有显著的拮抗作用，使剂量－效应曲线右移。在ＮＥ双相收缩实验中，二药均可显著抑制ＮＥ依外Ｃａ２＋性收缩反应，而对ＮＥ依内Ｃａ２＋性收缩反应无抑制作用。结论：ＭＣ９２０４扩血管作用强于ＮＩＦ，ＭＣ９２０４对肾动脉和肠系膜上动脉的抑制作用强于腹主动脉，具有一定的血管选择性作用，此作用通过抑制细胞外Ｃａ２＋的进入而实现。     

Development of an ELISA for detection of an organophosphorus compound using monoclonal antibodies

This paper describes a specific and highly sensitive ELISA system using monoclonal antibodies in order to assay an organophosphorus compound. The soman derivative methyl phosphonic acid, p-aminophenyl 1,2,2,-trimethyl-propyl diester (MATP) served as model substance. In order to obtain antibody-producing hybridomas BALB/c mice were immunized with MATP linked onto human serum albumin (HSA). The spleen cells of immunized mice were fused with syngenic plasmacytomas of the non-producer-line X63Ag8.653 with the aid of polyethylene glycol. To eliminate undesirable cross-reaction, common screening procedures were modified by directly coating the ELISA plates with hapten. Five out of 15 positive cell-lines were cloned by limiting dilution and further propagated. The respective immunoglobulin class and subclass of the obtained monoclonal antibodies was determined. Four of which were identified as IgG₁, the other as IgG_2a. After enrichment of antibodies in ascites and their isolation by protein A-sepharose, the affinity of various monoclonal antibodies was estimated in competitive inhibition enzyme immunoassay (CIEIA) by measuring the IC₅₀ rates of free MATP. The rates were found to lie between 2.5 × 10^–6 mol/l and 4.3 × 10^–4 mol/l MATP. The IC₁₀ rate for detectable MATP concentration was 5.4 × 10^–7 mol/l MATP. Test duration was 280 min. The reactivity of the monoclonal antibodies with structurally related substances was used to check their specificity. Cross-reaction turned out to be negative. In order to develop a direct competitive ELISA, MATP was linked to horse radish peroxidase (HRPO) by adding a spacer. This helped to reduce total duration to 40 min. The detection level was further reduced to 1.3 × 10^–7 mol/l MATP (corresponding to 975 pg/25 l test-buffer) using the monoclonal antibody F71D7. Likewise, MATP was detected in goat serum, chicken serum, rabbit serum, milk and company's water in concentrations between 2.1 × 10^–7 mol/l (IC₁₀, company's water) and 4.9 × 10^–8 mol/l (IC₁₀, milk).     

2，6-二甲基-4-(3-硝基苯基)-1，4-二氢-3，5-吡啶二羧酸-3-甲酯-5-正戊酯(MN9202)抗实验性血栓形成作用

目的：探讨新的二氢吡啶钙通道阻滞剂ＭＮ９２０２对实验性血栓形成的影响及其作用机制。方法：采用ｉｖ胶原肾上腺素或ｓｃ角叉菜胶，分别复制小鼠肺血栓和尾血栓模型。观察ＭＮ９２０２对实验性肺血栓小鼠死亡率，血栓黑尾形成率及微循环的影响。用凝血酶ＡＤＰ肾上腺素复合诱导剂，复制大鼠脑血栓模型，观察ＭＮ９２０２对大鼠脑血栓损伤的预防作用。结果：ＭＮ９２０２４ｍｇ·ｋｇ－１ｉｐ，能明显降低胶原肾上腺素引起的小鼠死亡率（３０ｖｓ８４Ｐ＜０．０１）；６ｍｇ·ｋｇ－１ｉｇ，对凝血酶诱导的大鼠脑血栓损伤具有保护作用（０．０６９±０．０６８ｖｓ０．１１０±０．０１３，Ｐ＜０．０１）；０．０４，０．４ｍｇ·ｋｇ－１能降低角叉菜胶诱导的血栓黑尾发生率（３０，１０ｖｓ９０，Ｐ＜０．０５；Ｐ＜０．０１），明显减轻微血管内皮的渗出，抑制血小板聚集和ＲＢＣ聚集，改善微血管血流速度。结论：ＭＮ９２０２具有对抗血小板聚集诱导剂及角叉菜胶引起的血栓形成作用。其机制可能与其抑制ＲＢＣ、血小板聚集，保护血管内皮，舒张痉挛血管有关。     

Rifampicin reverses nicardipine effect inducing uncontrolled essential hypertension

Dihydropyridine calcium‐channel blockers are a known substrate for the cytochrome P450 isoform 3A4. Rifampicin, an antitubercular agent, is one of the most potent inducers of hepatic and intestinal CYP3A4 thus increasing dihydropyridine metabolism. We report a case of a 67‐year‐old hypertensive female treated with a four‐drug antihypertensive regimen including a dihydropyridine (nicardipine 50 mg bid), who was admitted for septic arthritis of the knee requiring antibiotic treatment with teicoplanin 400 mg od and rifampicin 600 mg bid. Six days after rifampicin initiation, she presented with Posterior Reversible Encephalopathy Syndrome due to uncontrolled hypertension. We hypothesized that disequilibrium of previously controlled hypertension was partially due to nicardipine ineffectiveness. Plasma nicardipine concentration was assessed through high‐performance liquid chromatography 5 hours after coadministration of the two drugs and proved undetectable.     

RyR1 Deficiency in Congenital Myopathies Disrupts Excitation–Contraction Coupling

In skeletal muscle, excitation–contraction (EC) coupling is the process whereby the voltage‐gated dihydropyridine receptor (DHPR) located on the transverse tubules activates calcium release from the sarcoplasmic reticulum by activating ryanodine receptor (RyR1) Ca²⁺ channels located on the terminal cisternae. This subcellular membrane specialization is necessary for proper intracellular signaling and any alterations in its architecture may lead to neuromuscular disorders. In this study, we present evidence that patients with recessive RYR1‐related congenital myopathies due to primary RyR1 deficiency also exhibit downregulation of the alfa 1 subunit of the DHPR and show disruption of the spatial organization of the EC coupling machinery. We created a cellular RyR1 knockdown model using immortalized human myoblasts transfected with RyR1 siRNA and confirm that knocking down RyR1 concomitantly downregulates not only the DHPR but also the expression of other proteins involved in EC coupling. Unexpectedly, this was paralleled by the upregulation of inositol‐1,4,5‐triphosphate receptors; functionally however, upregulation of the latter Ca²⁺ channels did not compensate for the lack of RyR1‐mediated Ca²⁺ release. These results indicate that in some patients, RyR1 deficiency concomitantly alters the expression pattern of several proteins involved in calcium homeostasis and that this may influence the manifestation of these diseases.     

Endothelin in coronary artery disease

Abstract

Objectives. The aim of the present study was to compare changes in circulating levels of proopiomelanocortin (POMC) derivates and lactate after remote ischemic preconditioning (IPC) and physical exercise. Introduction. Remote IPC (rIPC) is cardioprotective following acute myocardial infarction and major cardiac surgery. A blood-borne, transferable factor, released following not only rIPC but also vigorous exercise, mediates protection that is abolished by naloxone suggesting involvement of an opioid-receptor-dependent pathway. Design. Eight healthy volunteers underwent rIPC by four cycles of 5-min inflation of a pneumatic tourniquet to 200 mmHg interrupted by 5 min of deflation. Subsequently, circulating plasma levels of POMC derivates, cortisol, and lactate were measured. After 3 days, the volunteers completed a vigorous exercise program, after which the same compounds were measured. Results. While rIPC was not associated with any significant increase in circulating POMC derivates or lactate, exercise induced significant elevation of both compared with baseline. Conclusions. We were not able to demonstrate a detectable increase in circulating POMC derivates by a standard rIPC stimulus, suggesting that rIPC effect is not mediated by local or detectable central release of these derivates.     

Excitation-contraction coupling in skeletal muscle: comparisons with cardiac muscle

1. The present review describes the mechanisms involved in controlling Ca2+ release from the sarcoplasmic reticulum (SR) of skeletal muscle, which ultimately regulates contraction. 2. Comparisons are made between cardiac and skeletal muscle with respect to: (i) the role of the dihydropyridine receptors (DHPR) as Ca2+ channels and voltage-sensors; (ii) the regulation of the ryanodine receptor (RyR)/Ca2+-release channels in the SR; and (iii) the importance of Ca2+-induced Ca2+ release. 3. It is shown that the key differences of the skeletal muscle Ca2+-release channel (RyR1), namely the increase in its stimulation by ATP and its inhibition by Mg2+, are critical for its direct regulation by the associated DHPR and, consequently, for the fast, accurate control of skeletal muscle contraction.     

4-噻吩基取代二氢吡啶新衍生物的合成

目的：设计并合成了4个4－噻吩基取代二氢吡啶新衍生物。方法：二氢吡环的4位引入电子等排体噻吩基，5位引入阿司区林，香豆素等。结果与结论：4个化合物的结构经^1HNMR,MS确证。     

Multiple H1-antihistamine-induced urticaria

H₁‐antihistamines are widely used in the treatment of various allergic diseases. Particularly, a cornerstone of the management of chronic idiopathic urticaria is treatment with H₁‐antihistamines. However, a few cases of H₁‐antihistamine‐induced urticaria have been reported. A 34‐year‐old woman presented with a 4‐month history of recurrent urticaria, which was prominently exacerbated by the administration of H₁‐antihistamines. The patient consented to a provocation test of fexofenadine among drugs including cetirizine and hydroxyzine, which were suspected of inducing severe symptoms in episodes. One hour after challenge with 12 mg fexofenadine (one‐fifth of the therapeutic dose), a urticarial reaction rapidly developed on nearly the entire body with remarkably increased levels of plasma histamine (190 nmol/L) and plasma leukotriene B4 (150 pg/mL). In challenge tests with other antihistamines, generalized urticaria occurred 5 and 1 h after intake of 10 mg loratadine and 10 mg bepotastine, respectively, whereas challenges with chlorpheniramine, mequitazine and azelastine were all negative. Skin prick tests with H₁‐antihistamines used in the challenges were all negative, indicating that the urticarial reactions after challenges with the causative drugs might not be immunoglobulin E‐mediated. Among the causative drugs in our case, cetirizine and hydroxyzine are the piperazine derivatives, whereas fexofenadine, bepotastine, ebastine and loratadine are the piperidine derivatives. The chemical structures of both derivatives are very similar. Therefore, in this case, H₁‐antihistamine‐induced urticaria may have been due to cross‐reactivity between metabolites of these drugs, but not to drugs before metabolization. Hypersensitivity to H₁‐antihistamines should be considered when urticarial lesions worsen after H₁‐antihistamine treatment.     

二氢吡啶类钙通道拮抗剂的剂型研究进展

二氢吡啶类钙拮抗剂是目前临床应用最广泛的抗高血压药物之一,但该类药物大多存在水溶性差和半衰期短等缺点。为此,研究人员尝试通过制剂学手段对该类药物的水溶性及半衰期等参数进行改进,并获得了一定成果。介绍了国内外有关二氢吡啶类钙拮抗剂的药物剂型研究进展,旨在为该类溶解性不佳或半衰期较短的药物的制剂开发提供一定参考。