B型肉毒毒素重链C端基因的克隆与表达

目的:扩增B型肉毒毒素重链C端基因并将其在大肠杆菌中表达.方法:首先克隆B型肉毒毒素重链C端片段(BoNTB/Hc),经IPTG诱导,在大肠杆菌中进行天然序列的表达.构建原核表达载体pET32/Hc后进行融合蛋白的表达.对5′端引物进行修饰,最终进行N端修饰蛋白的表达.结果:扩增得到的BoNTB/Hc与已知序列同源性达99%,未得到天然序列的表达,获得了融合蛋白和N端修饰蛋白的表达.Western blot鉴定结果表明,融合蛋白和N端修饰蛋白都可以和特异性抗体发生反应.结论:获得了B型肉毒毒素重链C端基因的表达,为肉毒毒素相关研究奠定了基础.     

B型肉毒毒素受体

美国威斯康星大学(UWI)的研究者已发现肉毒毒素如何阻止神经元中的神经递质释放，但尚不知毒素如何首先进入神经元。不管是吸入还是注入，毒素直接朝向神经元。毒素通过与神经元表面的受体结合，能被带入细胞，进而阻止神经递质的释放。     

A型肉毒毒素治疗偏侧面肌痉挛症

目的：观察Ａ型肉毒毒素对偏侧面肌痉挛症的疗效及安全性。方法：３５例偏侧面肌痉挛病人，在面肌痉挛部位多点皮下注射Ａ型肉毒毒素，每一点注射０．１ｍＬ（含２．５Ｕ）。结果：全部病例治疗后均在１ｗｋ内见效，１级和２级痉挛者７例，治疗后痉挛全部消失；３级痉挛２１例，１６例痉挛消失，５例转为１级；７例４级痉挛者除１例转为１级外，余痉挛全部消失。副作用有轻微眼睑下垂、鼻唇沟变浅。结论：Ａ型肉毒毒素治疗偏侧面肌痉     

A型肉毒毒素治疗偏侧面肌痉挛症

目的：观察Ａ型肉毒毒素对偏侧面肌痉挛症的疗效及安全性。方法：３５例偏侧面肌痉挛病人，在面肌痉挛部位多点皮下注射Ａ型肉毒毒素，每一点注射０．１ｍＬ（含２．５Ｕ）。结果：全部病例治疗后均在１ｗｋ内见效，１级和２级痉挛者７例，治疗后痉挛全部消失；３级痉挛２１例，１６例痉挛消失，５例转为１级；７例４级痉挛者除１例转为１级外，余痉挛全部消失。副作用有轻微眼睑下垂、鼻唇沟变浅。结论：Ａ型肉毒毒素治疗偏侧面肌痉挛疗效肯定，使用方便、安全。     

A型肉毒杆菌毒素

肉毒杆菌毒素是肉毒杆菌分泌的一种生物毒性蛋白质,其药理机制是与胆碱能神经末稍SNAP-25等蛋白产生作用,抑制乙酰胆碱释放,减少肌肉收缩和痉挛.目前,A型肉毒杆菌毒素获准用于治疗皱纹,其疗效平均持续4～6月,可以反复注射治疗.本文系统的回顾了A型肉毒杆菌毒的作用机制、临床试验、临床应用及不良反应.大量研究和病例分析已证明肉毒杆菌毒素注射术对于治疗面部各部位的皱纹是安全有效的.     

一起E型肉毒毒素食物中毒的调查分析

肉毒毒素是肉毒梭菌产生的外毒素 ,是一种强烈的神经毒素 ,毒性比氢化钾强 1万倍 ,对人致死量约为 0 .1μg。我国报道的肉毒中毒多为 A型 ,其次为B、E型 ,新疆察布查尔地区为多发地区[1] 。我省此类中毒的报道较为少见。现将发生在明光市某村民组的一起 E型肉毒毒素食物中毒事故的调查结果及原因分析如下。1　中毒发生经过2 0 0 1年某日中午 1 2时 ,明光市某村民组的某住户一家 6口共进午餐 ,餐后下午 5时有 1人出现上腹疼痛 ,未引起注意也未治疗。当晚 6时又在一起共同就餐 ,餐后约 1 0时首例腹痛患者症状加重并伴有视力模糊、呕吐 ,去本…     

A型肉毒毒素治疗眼睑痉挛的临床分析

用A型肉毒毒素局部注射,治疗睑痉挛患者26例。均于治疗后3～5天出现症状缓解;3周好转最明显;5个月后,复发10例。     

肉毒毒素在面部除皱中的应用进展

在面部抗衰老和美容治疗中,肉毒毒素因具有微创和安全、有效的特点,越来越被推广,肉毒毒素和软组织填充剂如透明质酸的联合使用也成为新的临床观察和研究的热点.     

Emerging Opportunities for Serotypes of Botulinum Neurotoxins

Background: Two decades ago, botulinum neurotoxin (BoNT) type A was introduced to the commercial market. Subsequently, the toxin was approved by the FDA to address several neurological syndromes, involving muscle, nerve, and gland hyperactivity. These syndromes have typically been associated with abnormalities in cholinergic transmission. Despite the multiplicity of botulinal serotypes (designated as types A through G), therapeutic preparations are currently only available for BoNT types A and B. However, other BoNT serotypes are under study for possible clinical use and new clinical indications; Objective: To review the current research on botulinum neurotoxin serotypes A-G, and to analyze potential applications within basic science and clinical settings; Conclusions: The increasing understanding of botulinal neurotoxin pathophysiology, including the neurotoxin’s effects on specific neuronal populations, will help us in tailoring treatments for specific diagnoses, symptoms and patients. Scientists and clinicians should be aware of the full range of available data involving neurotoxin subtypes A-G.     

Botulinum toxin for the management of adult patients with upper motor neuron syndrome

The upper motor neuron (UMN) syndrome is a collection of interactive positive signs (associated with spastic hypertonia) and negative signs, such as muscle weakness and loss of voluntary control. In clinical practice, the distinction between active and passive functions allows identifying appropriate treatment objectives. During the last decades, many studies have evaluated the possibility to treat UMN syndromes with botulinum neurotoxin (BoNT). They have shown that BoNT is effective in controlling upper limb spasticity in adults. The clinical improvement is more consistent in the distal joints and the reduction of muscle hypertonia is dose-dependent. The functional efficacy of BoNT for lower limb spasticity has not been documented as well, as some series report efficacy in reducing muscle tone in the lower limb, but not in improving walking.The functional benefit arising from the reduction of spasticity is often difficult to judge in the context of the complex phenomenology of the UMN syndrome. Certain data indicate that some disabilities related to passive and active function in the upper limb can improve with treatment. However, to date, the functional improvement after BoNT treatment in patients with UMN symptoms remains a point of ambiguity in the literature.BoNT is overall well tolerated and must be regarded as a safe treatment intervention. Safety data are abundant in the literature for type-A toxin and scant for type-B toxin. There is no clear evidence to suggest the best time to introduce BoNT injections in the management of UMN syndromes. A common sense approach would be to introduce BoNT treatment as early as possible, in order to prevent further complications including contractures.     

Structure and Function of Clostridium Botulinum Progenitor Toxin

Clostridium botulinum strains produce seven immunologically distinct neurotoxins (NTX), type A to G. the NTXs associate with nontoxic components in cultures, and become large complexes with three forms (12S, 16S, and 19S) designated progenitor toxins. the 12S toxin consists of a NTX and a nontoxic component having no hemagglutinin (HA) activity (described here as non-toxic non-HA, NTNH), and the 16S and 19S toxins are formed by conjugation of the 12S toxin with HA. Based on the genetic-and protein chemical-analyses of the progenitor toxins it became clear that 1) the HA consists of four subcomponents namely HA1 (Mr. 33–35 kDa), HA2 (15–17 kDa), HA3a (19–23 kDa), and HA3b (52–53 kDa), 2) the genes coding for NTX (ntx), NTNH (ntnh), and HA (ha) occur as a cluster; ha lies just upstream of ntnh, and ntx lies just downstream of ntnh, 3) ha is in the opposite orientation from that of ntnh and ntx, 4) ha consists of three ORFs (ha1, ha2, and ha3), 5) the gene product (70 kDa) of ha3 is split into HA3a and HA3b after translation, 6) HA3a is cleaved at several different sites of its N-terminal region to form proteins with slightly different Mrs, 7) the 19S toxin is a dimer of 16S toxin crosslinked by HA1, 8) the NTNHs of type A to D 12S toxins have a cleavage(s) on their N-terminal regions. It also became clear that the HA plays an important role when the 16S (and 19S) toxin is absorbed from the small intestine.     

Interaction of botulinum type A,B and E derivative toxins with synaptosomes of rat brain

Summary Clostridium botulinum ¹²⁵I-labelled derivative toxin immediately bound to rat synaptosomes. Of the two fragments of type B derivative toxin, the large-molecular-weight fragment (fragment I) inhibited the binding of labelled type B derivative toxin to synaptosomes in the same manner as unlabelled type B toxin did. The inhibition by the small-molecular-weight fragment (fragment II) was less than that by fragment I. These findings suggest that type B toxin binds to synaptosomes mainly with some part of fragment I. The binding of labelled type A and E derivative toxins was inhibited by either of the unlabelled type A or E derivative toxins, but not by type B derivative toxin. It is concluded that synaptosomes of rat brain possess relatively specific binding sites for botulinum toxin types.     

A型肉毒毒素治疗慢性偏头痛的临床疗效和安全性观察

目的：观察A型肉毒毒素( BTX-A)治疗慢性偏头痛的有效性和安全性。方法选取2012年9月—2014年9月慢性偏头痛患者39例,对每例患者给予BTX-A治疗,随访记录各时段(治疗前、治疗后1、2、3、6个月)各项观察指标的结果与评分,进行统计学分析。同时记录相关不良反应,来评价该药物的安全性。结果每月偏头痛发作频率、头痛发作持续时间、疼痛视觉模拟量表( VAS)评分、头痛强度、各等级头痛人数在治疗后各时段较治疗前均有改善(P<0．01)。 VAS评分在治疗后2个月时最低,重度头痛的人数变化最明显,疼痛缓解程度在治疗后2个月最明显。本实验共发生4例不良反应,未影响日常生活,轻度可逆。结论 BTX-A治疗慢性偏头痛效果显著,在临床应用中较安全。     

A型肉毒毒素治疗偏侧面肌痉挛的临床观察

目的探讨A型肉毒毒素治疗偏侧面肌痉挛的临床疗效。方法采用A型肉毒毒素局部多点注射治疗偏侧面肌痉挛142例,对治疗前后的病情随访并进行分级比较。结果症状完全缓解占54%,明显缓解占42%,部分缓解占4%,疗效平均持续约3~6个月,个别持续10个月左右,复发者重复注射仍有效,局部不良反应轻微短暂。结论局部注射A型肉毒毒素是治疗偏侧面肌痉挛一种安全有效且简便易行的手段。     

局部注射A型肉毒杆菌毒素治疗贲门失弛缓症临床疗效观察

目的:探讨局部注射A型肉毒杆菌毒素(BTA)治疗贲门失弛缓症的近期和远期临床疗效。方法:选择原发性贲门失弛缓症(PA)患者248例和假性贲门失弛缓症(SA)患者11例,内镜下在食管痉挛处注射BTA20IU,根据治疗前、后的临床症状缓解情况判定其疗效。结果:治疗1周后,所有PA患者的临床症状均有明显的缓解(100.0%),显著高于SA患者(18.2%)(P<0.001);PA患者治疗1、3、6个月的临床症状缓解总有效率达到91.5%、87.2%、77.0%,但治疗1、3、5、10年后总有效率只有51.1%、56.3%、49.0%、44.1%,长期疗效显著低于短期疗效(P<0.01)。结论:局部注射BTA治疗贲门失弛缓症的近期疗效较好,对PA和SA的鉴别也有一定价值。     

Monoclonal Antibodies that Inhibit the Proteolytic Activity of Botulinum Neurotoxin Serotype/B

Existing antibodies (Abs) used to treat botulism cannot enter the cytosol of neurons and bind to botulinum neurotoxin (BoNT) at its site of action, and thus cannot reverse paralysis. However, Abs targeting the proteolytic domain of the toxin could inhibit the proteolytic activity of the toxin intracellularly and potentially reverse intoxication, if they could be delivered intracellularly. As such, antibodies that neutralize toxin activity could serve as potent inhibitory cargos for therapeutic antitoxins against botulism. BoNT serotype B (BoNT/B) contains a zinc endopeptidase light chain (LC) domain that cleaves synaoptobrevin-2, a SNARE protein responsible for vesicle fusion and acetylcholine vesicle release. To generate monoclonal Abs (mAbs) that could reverse paralysis, we targeted the protease domain for Ab generation. Single-chain variable fragment (scFv) libraries from immunized mice or humans were displayed on yeast, and 19 unique BoNT/B LC-specific mAbs isolated by fluorescence-activated cell sorting (FACS). The equilibrium dissociation constants (K_D) of these mAbs for BoNT/B LC ranged from 0.24 nM to 14.3 nM (mean K_D 3.27 nM). Eleven mAbs inhibited BoNT/B LC proteolytic activity. The fine epitopes of selected mAbs were identified by alanine-scanning mutagenesis, revealing that inhibitory mAbs bound near the active site, substrate-binding site or the extended substrate-binding site. The results provide mAbs that could prove useful for intracellular reversal of paralysis and identify epitopes that could be targeted by small molecules inhibitors.     

Skeletal Muscle Atrophy Induced by Intramuscular Repeated Dose of Botulinum Toxin Type A in Rats

Botulinum toxin type A was intramuscularly administered to Sprague–Dawley rats once a day for 28 days at doses of 1, 3, and 9 ng kg^?1 day^?1 to investigate the possibility of unanticipated toxicity of repeated dose. A dose-related decrease in body weight gain was noted and lasted throughout the 4-week recovery period. Paralytic gait was a common clinical sign observed in the animals dosed at ≥3 ng kg^?1 day^?1 and muscle atrophy at 9 ng kg^?1 day^?1. Decreased creatinine was monitored in both males and females treated at 9 ng kg^?1 day^?1. Microscopic examination of the quadriceps femoris muscle, the test article application site, confirmed the muscle atrophy with a decrease in myofiber diameter and an increase of myofiber nuclei and intermyofiber connective tissue. Although antibody against botulinum toxin type A was detected in the sera from both males and females at 9 ng kg^?1 day^?1, no immunogenicity-related changes or lesions were noted. In conclusion, no other side effects of the botulinum toxin type A injection except the decrease in body weight gain and the muscle atrophy at the administration site were noted in the 28-day intramuscular repeated dose study.