Effect of Lignocaine on the Responses Produced by Depolarizing Agents at the Chick Neuromuscular Junction

The effect of lignocaine on the depolarization and contracture responses produced by acetylcholine (ACh) or tetraethylammonium (TEA) was studied in the isolated chick biventer cervicis (BVC) nerve-muscle preparation using the moving fluid electrode technique. Lignocaine (37 mumol X 1-1-1.8 mmol X 1-1) produced concentration-dependent contractures in the chick BVC muscle. The contractures produced by lignocaine were not accompanied by membrane depolarizations. ACh (5.5 mumol X 1-1-11.0 mmol X 1-1) and TEA (0.48-24.0 mmol X 1-1) produced concentration-dependent depolarizations and contractures in the chick BVC muscle. Lignocaine (0.93 mmol X 1-1) greatly reduced the responses produced by ACh, while it markedly increased the contracture responses produced by TEA. The depolarizations produced by TEA were reduced in lignocaine (0.93 mmol X 1-1). It was concluded that the local anaesthetic lignocaine produces contractures in the chick BVC muscle. Lignocaine potentiates the contractures produced by TEA, while it greatly reduces those produced by ACh.     

Comparison of the neurotoxic and myotoxic effects of Brazilian Bothrops venoms and their neutralization by commercial antivenom.

The venoms of some Bothrops species produce neuromuscular blockade in avian and mammalian nerve-muscle preparations in vitro. In this study, we compared the neuromuscular activities (myotoxicity and neurotoxicity) of venoms from several Brazilian species of Bothrops (B. jararaca, B. jararacussu, B. moojeni, B. erythromelas and B. neuwiedi) in chick isolated biventer cervicis muscle preparations and examined their neutralization by commercial antivenom. All of the venoms (50-200 microg/ml, n = 3 - 7 each) induced long-lasting, concentration-dependent muscle contracture and twitch-tension blockade, and also inhibited the muscle responses to acetylcholine and KCl. Preincubation of the venoms (200 microg/ml) with bothropic antivenom (0.2 ml) for 30 min at 37 degrees C prevented the twitch-tension blockade to different extents, with the protection varying from 0.5% (B. neuwiedi) to 88% (B. moojeni). Complete protection against the neuromuscular action of B. neuwiedi venom was observed only with a mixture of bothropic and crotalic antivenoms. The venoms caused either high (B. jararacussu, B. neuwiedi and B. moojeni) or low (B. jararaca and B. erythromelas) creatine kinase release. Morphologically, myonecrosis was greatest with B. jararacussu venom (98-100% of fibers damaged) and least with B. jararaca venom (74% damage). The extent of neutralization by bothropic antivenom was B. jararaca (93%)>B. erythromelas (65.8%)>B. moojeni (30.7%)>B. neuwiedi (20%)>B. jararacussu (no neutralization). Despite this variation in neutralization, enzyme-linked immunosorbent assays indicated similar immunoreactivities for the venoms, although immunoblots revealed quantitative variations in the bands detected. These results show that Bothrops venoms produce varying degrees of neuromuscular blockade in chick nerve-muscle preparations. The variable protection by antivenom against neuromuscular activity indicates that the components responsible for the neuromuscular action may differ among the venoms.     

树突状细胞活化的CTLs联合5-FU在裸鼠体内外对子宫颈癌的抑制作用

目的:探讨树突状细胞(DCs)活化的细胞毒T细胞(CTLs)联合5-氟尿嘧啶(5-FU)在裸鼠体内外对子宫颈癌的抑制作用。方法:MTT法检测DCs激活的CTLs联合5-FU在裸鼠体外对子宫颈癌细胞的抑制作用。裸鼠体内实验分为CTLs治疗组、5-FU治疗组、CTLs/5-FU治疗组及对照组,观察移植瘤成瘤率、潜伏期、瘤重及瘤体积。结果:治疗组在裸鼠体外都显著抑制子宫颈癌细胞生长,CTLs/5-FU治疗组最显著(P<0.01)。裸鼠体内实验中,治疗组的成瘤率、瘤体积、瘤重都显著降低,潜伏期延长,CTLs/5-FU治疗组最显著(P<0.01)。结论:联合应用DCs激活的CTLs及5-FU比单独应用CTLs或5-FU更有效。     

Modulation of intracellular Ca2+ levels by Scorpaenidae venoms.

The crude venoms of the soldierfish (Gymnapistes marmoratus), the lionfish (Pterois volitans) and the stonefish (Synanceia trachynis) display pronounced neuromuscular activity. Since [Ca(2+)](i) is a key regulator in many aspects of neuromuscular function we sought to determine its involvement in the neuromuscular actions of the venoms. In the chick biventer cervicis muscle, all three venoms produced a sustained contraction (approx 20-30% of 1mM acetylcholine). Blockade of nicotinic receptors with tubocurarine (10 micro M) failed to attenuate the contractile response to either G. marmoratus venom or P. volitans venom, but produced slight inhibition of the response to S. trachynis venom. All three venoms produced a rise in intracellular Ca(2+) (approx. 200-300% of basal) in cultured murine cortical neurons. The Ca(2+)-channel blockers omega-conotoxin MVIIC, omega-conotoxin GVIA, omega-agatoxin IVa and nifedipine (each at 1 micro M) potentiated the increase in [Ca(2+)](i) in response to G. marmoratus venom and P. volitans venom, while attenuating the response to S. trachynis venom. Removal of extracellular Ca(2+), replacement of Ca(2+) with La(3+) (0.5mM), or addition of stonefish antivenom (3units/ml) inhibited both the venom-induced increase in [Ca(2+)](i) in cultured neurones and contraction in chick biventer cervicis muscle. Venom-induced increases in [Ca(2+)](i) correlated with an increased cell death of cultured neurones as measured using propidium iodide (1 micro g/ml). Morphological analysis revealed cellular swelling and neurite loss consistent with necrosis. These data indicate that the effects of all three venoms are due in part to an increase in intracellular Ca(2+), possibly via the formation of pores in the cellular membrane which, under certain conditions, can lead to necrosis.     

Limitation of activities of daily living accompanying reduced neck mobility after laminoplasty preserving or reattaching the semispinalis cervicis into axis

Although difficulties with neck mobility often interfere with patients’ activities of daily living (ADL) after cervical laminoplasty, there was no detailed study on the relation between the limitations of ADL accompanying postoperative reduced neck mobility and the cervical posterior approach. The aim of this study was to compare retrospectively the frequency of limitations of ADL accompanying neck mobility after laminoplasty preserving the semispinalis cervicis inserted into the C2 spinous process with that after laminoplasty reattaching the muscle to C2. Forty-nine patients after C4–C7 laminoplasty with C3 laminectomy preserving the semispinalis cervicis inserted into C2 (Group A) and 24 patients after C3–C7 laminoplasty reattaching the muscle (Group B) were evaluated. The frequency of postoperative limitations of ADL accompanying each of three neck movements of extension, flexion and rotation were investigated. The postoperative O–C7 angles at extension and flexion was measured on lateral extension and flexion radiographs of the cervical spine, respectively. The postoperative cervical range of motion in rotation was measured in the cranial view using a digital camera. Frequency of limitations of ADL accompanying extension was lower (P = 0.037) in Group A (2%) than in Group B (17%). Frequency of limitations of ADL accompanying flexion was similar in Group A (8%) and Group B (4%). Frequency of limitations of ADL accompanying rotation was lower (P = 0.031) in Group A (12%) than in Group B (33%). Average O–C7 angle at extension was significantly larger (P = 0.002) in Group A (147°) than in Group B (136°). Average O–C7 angle at flexion was similar in Group A (93°) and Group B (91°). Average range of motion in rotation was significantly larger (P = 0.004) in Group A (110°) than in Group B (91°). This retrospective study suggested that the frequency of limitations of ADL accompanying neck extension or rotation was lower after laminoplasty preserving the semispinalis cervicis inserted into C2 than after laminoplasty reattaching the muscle.     

金环蛇毒的分离及组分Ⅸ的初步研究

从金环蛇毒中分离到一个神经毒—组分Ⅸ。该组分阻断小鸡颈二腹肌神经肌肉接头传递;阻断标本对乙酰胆碱的反应,标本对直接电刺激以及对高浓度钾离子的反应性仍然存在;组分Ⅸ使蛙缝匠肌终板电位,微终板电位振幅逐渐减小,最后完全消失;但不影响微终板电位的发放频率,也不影响肌纤维的静息膜电位。实验表明组分Ⅸ是作用于突触后膜的神经毒。     

Pharmacological characterisation of a neurotoxin from the venom of Boiga dendrophila (mangrove catsnake).

In this study, we have pharmacologically characterised boigatoxin-A, a three finger toxin isolated from the venom of the colubrid, Boiga dendrophila (Mangrove catsnake). In the chick biventer cervicis nerve-muscle preparation boigatoxin-A (1 microM) displayed poorly reversible postsynaptic blockade as evidenced by the inhibition of indirect (0.1 Hz, 0.2 ms, supramaximal V) twitches and responses to exogenous acetylcholine (1 mM) and carbachol (20 microM). Boigatoxin-A (0.3-0.5 microM) caused a concentration-dependent depression of the maximum response of cumulative concentration response curves to CCh (0.6-80 microM). Boigatoxin-A (1 microM) induced readily reversible inhibition of electrically evoked (0.2 Hz, 0.3 ms, 70-100 V) twitches of the prostatic segment of the rat vas deferens. This inhibition was not significantly attenuated by 8-phenyltheophylline (20 microM) or idazoxan (1 microM). Boigatoxin-A (1 microM) did not affect alpha,beta-mATP (10 microM) or noradrenaline (25 microM) responses in unstimulated epididymal segments of the rat vas deferens. Our data suggests that this toxin has weak postsynaptic neurotoxicity in skeletal muscle and also prejunctional neurotoxic activity in the smooth muscle of the rat vas deferens to inhibit the release of neurotransmitter(s), but not via prejunctional purinergic or adrenergic receptors. This is the first report of such activity for a toxin isolated from snake venom and reinforces the largely untapped potential of colubrid venoms.     

Isolation and characterization at cholinergic nicotinic receptors of a neurotoxin from the venom of the Acanthophis sp. Seram death adder

The present study describes the isolation of the first neurotoxin (acantoxin IVa) from Acanthophis sp. Seram death adder venom and an examination of its activity at nicotinic acetylcholine receptor (nAChR) subtypes. Acantoxin IVa (MW 6815; 0.1-1.0 microM) caused concentration-dependent inhibition of indirect twitches (0.1 Hz, 0.2 ms, supramaximal V) and inhibited contractile responses to exogenous nicotinic agonists in the chick biventer cervicis nerve-muscle, confirming that this toxin is a postsynaptic neurotoxin. Acantoxin IVa (1-10 nM) caused pseudo-irreversible antagonism at skeletal muscle nAChR with an estimated pA2 of 8.36+/-0.17. Acantoxin IVa was approximately two-fold less potent than the long-chain (Type II) neurotoxin, alpha-bungarotoxin. With a pKi value of 4.48, acantoxin IVa was approximately 25,000 times less potent than alpha-bungarotoxin at alpha7-type neuronal nAChR. However, in contrast to alpha-bungarotoxin, acantoxin IVa completely inhibited specific [3H]-methyllycaconitine (MLA) binding in rat hippocampus homogenate. Acantoxin IVa had no activity at ganglionic nAChR, alpha4beta2 subtype neuronal nAChR or cytisine-resistant [3H]-epibatidine binding sites. While long-chain neurotoxin resistant [3H]-MLA binding in hippocampus homogenate requires further investigation, we have shown that a short-chain (Type I) neurotoxin is capable of fully inhibiting specific [3H]-MLA binding.     

子宫颈癌患者新辅助化疗前后癌组织中mdr1、肺耐药蛋白mRNA及其蛋白的表达变化和意义

目的寻找预测子宫颈癌新辅助化疗效果的分子生物学指标。方法采用real time RT—PCR和免疫组织化学法检测40例子宫颈癌患者新辅助化疗前后癌组织中mdr1、肺耐药蛋白（LRP）mRNA及其编码蛋白P-gP、LRP表达水平。结果新辅助化疗前后子宫颈癌组织中mdr1的表达量分别为（45．800±0．636、62．381±0．743,t=-66．582,P〈0．01）;新辅助化疗前后子宫颈癌组织中LRP mRNA的表达量分别为（50．048±0．770、66．912±0．752,t=-78．604,P〈0．01）;新辅助化疗前后子宫颈癌组织中P-gP的阳性表达分别为40．0％（16／40）、70．0％（28／40）,x^2=7．273,P=0．007;新辅助化疗前后子宫颈癌组织中LRP的阳性表达分别为62．5％（25／40）、92．5％（37／40）,x^2=10．323,P=0．001,新辅助化疗后mdr1、LRPmRNA及其编码蛋白P-gP、LRP表达水平较化疗前明显升高,2组比较差异有统计学意义（P〈0．01）。P-gP、LRP表达与患者年龄、肿瘤大小、临床分期、病理分级无关（P〉0．05）;P-gP蛋白的阳性与阴性患者其化疗有效率分别为6（37．5％）、17（70．8％）,2组比较差异有统计学意义（x^2=4．365,P〈0．05）。LRP蛋白的阳性与阴性患者其化疗有效率分别为12（48．0％）、13（86．7％）,2组比较差异有统计学意义（x^2=5．980,P〈0．05）;P-gP与LRP成正相关（x^2=4．177,r=0．323,P〈0．05）。结论P-gP、LRP表达状态有可能作为预测化疗效果的参考指标。     

彩色多普勒超声诊断子宫颈部肌瘤的价值

目的：探讨彩色多普勒超声对子宫颈部肌瘤的声像图特征及其相应的生理、病理学基础,提高彩色多普勒超声对子宫颈部肌瘤的诊断率。材料与方法：采用彩色多普勒超声检查,分析经手术和病理证实的39例子宫颈部肌瘤的声像图表现。结果：子宫颈部黏膜下肌瘤11例、肌壁间肌瘤23例、浆膜下肌瘤5例,误诊3例,诊断符合率为92.3%,误诊率为7.7%。结论：彩色多普勒超声对子宫颈部肌瘤有很高的诊断价值。