Fig. 2: Assay for the endoprotease activity of botulinumneurotoxin A: general principle.
A sample containing BoNT/A was injected 300 sec over the SNAP-25 sensorchip. The deflection to approximately 600 RU and complete return to baseline reflects the change in refractive index during sample injection, irrespective of the presence (red trace) or absence (black trace) of BoNT/A (400 fM). MAb10F12 was then injected to detect epitopes generated by BoNT/A activity. The difference between red and black traces) corresponds to specific mAb binding, and indicates the number of neo-epitopes produced, which is directly related to BoNT/A activity. Each trace represents a sensorgram monitored in the single flow-cell of a Biacore sensor chip.
The patterns of relative expression for all botulinum toxin locus genes were identical in strains Hall and NCTC 2916 as well as in non-sporulated and sporulated cultures, although
organization, with two botulinum toxin locus genes. One is similar to that from type A1 strains, including ntnh, botR and has genes, but its bont/A gene is replaced with a silent bont/B gene, while the other locus is typical of type A2 strains but has a bont/A type A1 gene and is organized in two operons, p47-ntnh/A-bont/A1 and orfx1-orfx2-orfx3 (Dineen et al., 2004; Henderson et al., 1996; Jovita et al., 1998). The botulinum toxin locus genes were concomitantly expressed and their kinetics showed a bell-shaped curve (Fig. 2). A low expression level was measured during entry into exponential growth, and maximal expression (50- to 200-fold increase compared to the baseline) occurred during the transition phase. Expression of the botulinum toxin locus genes then decreased to baseline at about 24 h of culture. A small increase in gene expression was observed late (48 h) in sporulated strain Hall cultures. Synchronous expression of botR/A, bont/A and antp genes, as well as botR/A being expressed about 100-fold less than the other botulinum toxin locus genes, further supports the hypothesis that BotR/ A is a regulatory factor controlling bont/A and antp gene expression. In addition, the RT-PCR results clearly show that botR/A, bont/A and antp gene expression was mainly restricted to late exponential growth/early stationary phase, indicating that BotR/A is an alternative sigma factor specific to the transition phase and independent of sporulation. The time correlation between the expression of BotR/A and botulinum toxin locus genes suggests that BotR/A is the main regulatory factor. However, this does not rule out that another regulatory or sigma factor is also involved. These results are in agreement with a recent report showing by Northern hybridizations that bontA, ntnhA and ha genes are temporally expressed during late exponential and early stationary phase in C. botulinum type A strains 62A, Hall A-hyper and NCTC 2916 (Bradshaw et al., 2004). It is noteworthy that TxeR from C. difficile is also predominantly expressed during the transition phase, as evidenced by a fusion between a b-glucuronidase reporter gene and TxeR in C. perfringens (Karlsson et al., 2003).
Botulinumneurotoxin (BoNT) treatment is the accepted standard of care for patients with CD and the preferred toxin type is BoNT-A. There are a number of published guidelines which deal with the general aspects, but do not cover the many practical variables that influence outcome of BoNT treatment for CD [ 4 – 6 ]. The success of treatment is very dependent on the experience and ability of the injector, both to identify and to treat the involved muscles, yet there is little practical guidance available to help the treating physician achieve op- timal results. Additionally, as experienced injectors, we have observed that patients have different individual needs and expectations of treatment. There may also be different per- ceptions between the patient and the treating physician on what should be the goals of treatment and what is deemed a satisfactory outcome. Therefore, an international group of neurologists, experts in this area, were brought together to produce consensus statements about the key practical issues
Oral medication has a limited role. Trihexyphenidyl is classically proposed, but the tolerance profile is low ( 5 ). Benzodiazepines, especially diazepam and clonazepam, mainly reduce dystonia-related pain, anxiety, and possibly dystonic tremor ( 6 ). Tetrabenazine, although possibly effective ( 7 ), is lim- ited by the frequent side effect of depression and parkinsonism. Evidence on the effectiveness of allied care treatments, including physiotherapy and cognitive behavioral therapy, is scanty ( 8 ). In those with unsatisfactory botulinumneurotoxin (BoNT) effect, surgery may be considered. Peripheral surgery, such as selective peripheral denervation, can provide improvement in about two-thirds of cases, with frequent relapses and is now rarely performed ( 9 , 10 ). Deep brain stimulation (DBS) of the globus pallidus pars interna appears to be a better choice, despite potential severe complications ( 11 ). Alternative DBS targets, such as the subthalamic nucleus, need further investigation ( 12 ).
nutrients (2): these strategies use anti –vascular-targeting agents (3) and antiangiogenic agents (4). The major difference between antiangiogenic and vascular-targeting agents is that the latter are directed at the preexisting tumor vasculature, whereas the former are designed to affect the process of development. In contrast to previous strategies, the goal of the ‘‘provascular’’ approaches is to increase tumor perfusion and oxygenation temporarily through pharmacologic interventions. For this latter approach, radiotherapy could benefit from tumor reoxygenation because oxygen is a key factor in the response to irradiation (5). Additionally, a decrease in tumor interstitial pressure (6) or a normalization of the tumor vasculature at the early phase of an antiangiogenic treatment (7 –9) could facilitate tumor accessibility to circulating chemotherapeutic drugs. Although such strategies seem rather simple, their implementation is not straightforward, because it is generally thought that structural and functional abnormalities of the immature tumor vessels could confer resistance to the relaxing properties of classic vasoactive drugs. Therefore, there is a real need for developing ways of transiently opening the tumor vascular bed to alleviate tumor hypoxia and increase the efficacy of anticancer cytotoxic therapies. In this study, we explored the role of Botulinumneurotoxin type A (BoNT-A) as a promising adjuvant to anticancer therapies.
Methods: Twenty-eight patients diagnosed with TMD were included in this study. In accordance with the Research Diagnostic Criteria for Temporomandibular Disorders, all patients had myofascial pain. They received botulinum toxin A (BTX-A) injections in temporalis and masseter muscles. QoL was measured using a French translated version of the validated Oral Health Impact Profile-14 (OHIP-14) and a second questionnaire, which was an adaptation of the temporomandibular joint replacement QoL questionnaire (TMJ-QoL). Patients answered both questionnaires and a visual analogue scale (VAS) before the injection, at 1 month after the injection and at 3 months after the injection. Relationship between QoL and factors such as bruxism, age, sex and body mass index (BMI) were also evaluated.
Accepted Jul 31, 2015; Epub ahead of print Oct 1, 2015
Local injection of botulinum toxin-type A (BTx-A) is the stand- ard treatment for focal spasticity, particularly in post-stroke patients. BTx-A acts by blocking the release of acetylcholine from motoneuron terminals at the neuromuscular junction, re- lieving excessive muscle contraction for up to several months. In addition to its peripheral local action, there is evidence for a central effect of BTx-A (1–6). Through blocking the end- plates of intrafusal muscle fibres (7–10), BTx-A may reduce discharge firing from muscle spindles, which may, in turn, alter the functioning of the central motor networks fed by spindle afferents at both spinal and supraspinal levels. Furthermore, animal experiments have shown that BTx-A can be transported retrogradely in the motor axon to motoneuron soma and pos- sibly trans-synaptically (6, 11), hence inhibiting cholinergic synaptic transmission in the spinal cord, as recently suggested for humans (12).
β-N-Methylamino-l-alanine (BMAA), a neurotoxin naturally produced by cyanobacteria, diatoms and dinoflagellates, constitutes a serious environmental and health threat especially during acute blooms, which are becoming more frequent. This neurotoxin is implicated in several neurodegenerative diseases (ND) in humans through contaminated water or food consumption. Even low doses of neurotoxic compounds (NCs) can have lasting effects later in life. In this sense, early stages of development constitute a period of high sensitivity to environmental influence, particularly for the central nervous system. To understand the mechanisms underlying the delayed effects of NCs, newly hatched larvae of the mangrove rivulus fish, Kryptolebias marmoratus, were exposed to two sub-lethal doses of BMAA (20 μg/L and 15 mg/L) for 14 days. This fish naturally produces isogenic lineages due to its self-fertilizing reproduction, which is unique case among vertebrates. It thus provides genetic characteristics that allow scientists to study organisms’ true reaction norm, minimizing genetic variability and focusing exclusively on the effects of the environment. Effect assessment was performed at different levels of biological organization to detect inconspicuous effects of BMAA, since this molecule displays long retention in organisms. BMAA effects on life history traits as well as behavioral traits such as boldness and aggressiveness were assessed more than 100 days after exposure. In addition, the relative expression of 7 potential BMAA target genes was studied, given their involvement in neurotransmission or their association with individual variation in boldness and aggressiveness. Selected genes code for reticulon 4 (RTN4), glutamate vesicular transporter 1 (Slc17a7), glutamine synthetase a (Glula), dopamine receptor D4 (DRD4), monoamine oxidase A (MAOA), calmodulin (CaM) and epedymine (Epd). Despite observing no effects of BMAA on growth, reproduction and behavioral traits, BMAA induced a significant increase of the expression of CaM and MAOA genes at 20 μg/L BMAA compared to the control group. A significant decrease of expression was observed between this lowest BMAA dose and 15 mg/L for DRD4, MAOA and CaM genes. Our results suggest disruption of glutamate turnover, intracellular dopamine depletion and activation of astrocyte protective mechanisms, indicating that BMAA might be excitotoxic. Our study revealed that BMAA can have long-lasting effects on the brain that are suspected to affect phenotypic traits with aging. Furthermore, it highlights the importance of studying delayed effects in ecotoxicological studies.
A comparative study has assessed the ef ﬁcacy of ultrasound-based tracking with an electrostimulation-based technique. 9 The authors evaluated 32 children presenting with cerebral palsy sequelae, who were divided into two groups. All received botulinum toxin injection into the gastrocnemius, which was guided by either ultrasound or electrostimulation depending on the group. The techni- ques were evaluated based on three different scales: the Ashworth (see online supplementary appendix 1), Tardieu (see online supplementary appendix 2), 10 selective motor control (SMC) 9 and Physician Rating scales. The authors observed a non-signi ﬁcant improvement in spasticity, assessed by the Ashworth and Tardieu scales, at 3 months postinjection, in the group treated with ultrasound-guided injections. In contrast, the electrostimulation-guided group showed non-signi ﬁcant improvement in motor control of the antagonistic muscles. The only signi ﬁcant differences revealed were improvements in walking pattern and foot-to-ground contact in the ultrasound-guided group. Nonetheless, the numerous controversial methodological choices made by the authors limited the relevance of these results.
neurotoxin 1-methyl-4-phenyl-1,2,3,6,-tetrahydropyridine (MPTP), administered to mouse brain slices increases n−6 and decreases n−3 PUFAs while increasing the expression of cPLA2 and COX-2.
Previous studies investigating the neuroprotective effects of n−3 fatty acids in experimental models of Parkinson's disease mainly used ﬁsh oil containing the long chain n−3 PUFA docosahexaenoic acid (DHA), but less EPA. Although EPA is far less abundant in the brain than DHA, it is highly neuroactive ( Horrobin, 2002 ), has more potent anti-inﬂammatory effects ( Mickleborough et al., 2009; Sierra et al., 2008 ) and is more effective than DHA in the treatment of psychiatric disorders ( Peet and Stokes, 2005 ). Therefore, presently, the second objective was to test the hypothesis that EPA supplementation to mice can reverse the effects of acute MPP + and that these effects are
20 their treatment after two years (63), linked to a lack of subjective efficacy and the unbalance between efficacy and weakness caused by the injections.
Botulinum toxin was first isolated from a clostridium bacterium. Its mechanism of action as a blocker of neuromuscular transmission was discovered in 1949. It was first used in strabismus in 1977. It acts by inhibiting acetylcholine release by the presynaptic nerve termination in the neuromuscular junction, whose consequence is a motor weakness (extrafusal effect). However, weakness and efficacy are not correlated. Thus, it has been proposed that BOT also acts on the muscles spindles (mechanoreceptors sensible to muscle elongation: intrafusal effect), which consequence is a diminished tonic vibration response, which can last up to 7 months after toxin injection. This effect is thought to modulate peripheral afferences to the brain, and by
Searches were performed on the following publication databases: Pubmed, Scopus, CINAHL, Embase, PsycINFO, and CENTRAL. Studies published in English and on or before 31 December 2018 were selected. Selected keywords included stroke, cerebral vascular accident, ischemic stroke, hemorrhagic stroke, botulinum toxin, botulinum toxin therapy, antispastic therapy, rehabilitation, physical therapy, occupational therapy, intensive rehabilitation, multidisciplinary rehabilitation, motor, function, ability, walk, and capacity. Variations of keywords were individualized for each scientific database. The references of all retrieved articles were reviewed to ensure that all relevant articles were included for data synthesis. As an example, the Pubmed search strategy is illustrated in Appendix A . 5.2. Date Collection and Analysis
The final publication is available at http://dx.doi.org/10.1111/liv.12518
Rose, C.F., 2014. Ammonia: more than a neurotoxin? Liver International, 34(5), p.649-651.
our group, where we recently demonstrated that by preventing the development of hyperammonaemia in bile-duct ligated- induced cirrhotic rats with AST-120 (carbon microspheres), the degree of liver damage was not alleviated . In addition, Jover and colleagues elegantly demonstrated that inducing hyperammonaemia by feeding naïve rats with a high ammonia diet did not result in alterations in liver biochemistry . Also, congenital portal-systemic shunting-induced
A role for endocytosis and exocytosis in cell migration has been proposed but not yet demonstrated. Here we show that cellubrevin, an early endosomal v-SNARE, mediates trafficking in the lamellipod of migrating epithelial cells and partially colocalizes with markers of focal contacts. Expression of tetanus neurotoxin, which selectively cleaves cellubrevin, significantly reduced the speed of migrating epithelial cells. Furthermore, expression of tetanus neurotoxin enhanced the adhesion of epithelial cells to collagen, laminin, fibronectin and E-cadherin, altered spreading on collagen, and impaired the recycling of β1 integrins. These results suggest that cellubrevin-dependent membrane trafficking participates in cell motility through the regulation of cell adhesion.
bone in rodents, to improve our understanding of how bone responds to mechanical forces. Rodent disuse models can roughly be divided into two categories: (1) those that remove or reduce external ground reaction forces but spare muscle activation (e.g., hind limb unloading [HLU] [ 5 ], limb immobilization [ 6 ], cast immobilization [ 7 ], partial weight suspension [ 8 ]) and (2) those that eliminate muscle contractions but permit external forces (e.g., botulinum toxin [BTX] [ 9 ], neurectomy [ 10 ], tendon resection [ 11 ]). Although these two categories are useful for generally characterizing the disuse models, it is clear that the in vivo situation is more complex than implied by these two broad categories. Indeed, muscle and external forces are intri- cately linked in vivo; and thus, it is impracticable to manipulate one loading modality without affecting the other. For instance, muscle contractions are permitted in the HLU model, but muscle forces are theoretically reduced since they need not oppose the torque of the ground reaction forces. Analogously, in the BTX model, intramuscular injection of BTX in hind limbs elicits tem- porary muscle paralysis, which secondarily alters gait and impacts external forces such that peak ground reaction forces are reduced by 11 % 4 days after BTX injection [ 12 ]. These limitations notwithstanding, these models are valuable tools to study the relative musculoskeletal effects of the removal of ground reaction forces versus the removal of muscle forces.