Discoveries in structure and physiology of mechanically activated ion channels.

The ability to sense physical forces is conserved across all organisms. Cells convert mechanical stimuli into electrical or chemical signals via mechanically activated ion channels. In recent years, the identification of new families of mechanosensitive ion channels-such as PIEZO and OSCA/TMEM63 channels-along with surprising insights into well-studied mechanosensitive channels have driven further developments in the mechanotransduction field. Several well-characterized mechanosensory roles such as touch, blood-pressure sensing and hearing are now linked with primary mechanotransducers. Unanticipated roles of mechanical force sensing continue to be uncovered. Furthermore, high-resolution structures representative of nearly every family of mechanically activated channel described so far have underscored their diversity while advancing our understanding of the biophysical mechanisms of pressure sensing. Here we summarize recent discoveries in the physiology and structures of known mechanically activated ion channel families and discuss their implications for understanding the mechanisms of mechanical force sensing.

Antibodies from Rabbits Immunized with HIV-1 Clade B SOSIP Trimers Can Neutralize Multiple Clade B Viruses by Destabilizing the Envelope Glycoprotein.

The high viral diversity of HIV-1 is a formidable hurdle for the development of an HIV-1 vaccine. Elicitation of broadly neutralizing antibodies (bNAbs) would offer a solution, but so far immunization strategies have failed to efficiently elicit bNAbs. To overcome these obstacles, it is important to understand the immune responses elicited by current HIV-1 envelope glycoprotein (Env) immunogens. To gain more insight, we characterized monoclonal antibodies (MAbs) isolated from rabbits immunized with Env SOSIP trimers based on the clade B isolate AMC008. Four rabbits that were immunized three times with AMC008 trimer developed robust autologous and sporadic low-titer heterologous neutralizing responses. Seventeen AMC008 trimer-reactive MAbs were isolated using antigen-specific single B-cell sorting. Four of these MAbs neutralized the autologous AMC008 virus and several other clade B viruses. When visualized by electron microscopy, the complex of the neutralizing MAbs with the AMC008 trimer showed binding to the gp41 subunit with unusual approach angles, and we observed that their neutralization ability depended on their capacity to induce Env trimer dissociation. Thus, AMC008 SOSIP trimer immunization induced clade B-neutralizing MAbs with unusual approach angles with neutralizing effects that involve trimer destabilization. Optimizing these responses might provide an avenue to the induction of trimer-dissociating bNAbs. IMPORTANCE Roughly 32 million people have died as a consequence of HIV-1 infection since the start of the epidemic, and 1.7 million people still get infected with HIV-1 annually. Therefore, a vaccine to prevent HIV-1 infection is urgently needed. Current HIV-1 immunogens are not able to elicit the broad immune responses needed to provide protection against the large variation of HIV-1 strains circulating globally. A better understanding of the humoral immune responses elicited by immunization with state-of-the-art HIV-1 immunogens should facilitate the design of improved HIV-1 vaccine candidates. We identified antibodies with the ability to neutralize multiple HIV-1 viruses by destabilization of the envelope glycoprotein. Their weak but consistent cross-neutralization ability indicates the potential of this epitope to elicit broad responses. The trimer-destabilizing effect of the neutralizing MAbs, combined with detailed characterization of the neutralization epitope, can be used to shape the next generation of HIV-1 immunogens to elicit improved humoral responses after vaccination.

Fine-mapping the immunodominant antibody epitopes on consensus sequence-based HIV-1 envelope trimer vaccine candidates.

The HIV-1 envelope glycoprotein (Env) trimer is the key target for vaccines aimed at inducing neutralizing antibodies (NAbs) against HIV-1. The clinical candidate immunogen ConM SOSIP.v7 is a stabilized native-like HIV-1 Env trimer based on an artificial consensus sequence of all HIV-1 isolates in group M. In preclinical studies ConM SOSIP.v7 trimers induced strong autologous NAb responses in non-human primates (NHPs). To fine-map these responses, we isolated monoclonal antibodies (mAbs) from six cynomolgus macaques that were immunized three times with ConM SOSIP.v7 protein and boosted twice with the closely related ConSOSL.UFO.664 immunogen. A total of 40 ConM and/or ConS-specific mAbs were isolated, of which 18 were retrieved after the three ConM SOSIP.v7 immunizations and 22 after the two immunizations with ConSOSL.UFO.664. 22 mAbs (55%) neutralized the ConM and/or ConS virus. Cross-neutralization of ConS virus by approximately one-third of the mAbs was seen prior to ConSOSL.UFO.664 immunization, albeit with modest potency. Neutralizing antibodies predominantly targeted the V1 and V2 regions of the immunogens, with an apparent extension towards the V3 region. Thus, the V1V2V3 region is immunodominant in the potent NAb response elicited by two consensus sequence native-like HIV-1 Env immunogens. Immunization with these soluble consensus Env proteins also elicited non-neutralizing mAbs targeting the trimer base. These results inform the use and improvement of consensus-based trimer immunogens in combinatorial vaccine strategies.

International consensus statement for the use of botulinum toxin treatment in adults and children with neurological impairments--introduction.

Botulinum neurotoxin (BoNT) is most commonly used to reduce focal over-activity in skeletal muscle, although newer indications such as management of drooling, pain and tremor are emerging. Treatment of spasticity incorporating BoNT is usually part of an integrated multidisciplinary rehabilitation programme. Prior to initiating this therapy, specific functional limitations, goals and expected outcomes of treatment should be discussed with the patient/carers. Muscle selection and the order/priority of treatment should be agreed. Treatment goals may involve increasing active or passive function or the avoidance of secondary complications or impairment progression. This paper describes the basic science mechanisms of the action of BoNT and subsequent nerve recovery and introduces a supplement comprising the best available evidence and expert opinion from international panels on questions of assessment, indications, BoNT regimen, adjunctive therapy, expected outcomes and recommended monitoring. Speciality areas reviewed include Paediatric Lower Limb Hypertonicity, Paediatric Upper Limb Hypertonicity, Adult Lower Limb Hypertonicity, Adult Upper Limb Hypertonicity, Cervical Dystonia, Drooling and Pain and Niche Indications. There is good quality scientific evidence to support the efficacy of BoNT to reduce muscle over-activity in the limbs secondary to central nervous system disorders in adults and children, to address primary or secondary cervical dystonia, to reduce saliva flow and to treat some pain syndromes. There is emergent evidence for the efficacy of BoNT to reduce focal tremor, to treat other types of pain including neuropathic pain and also to improve function following treatment of focal muscle over-activity.

Botulinum toxin assessment, intervention and aftercare for lower limb disorders of movement and muscle tone in adults: international consensus statement.

Lower limb disorders of movement and muscle tone in adults significantly impact quality of life. The management of the patient with hypertonia is complex and requires a multidisciplinary team working with the patient and family/carers. Botulinum neurotoxin type A (BoNT-A) has been used as a component of this management to reduce lower limb hypertonia, increase passive range of motion and reduce associated pain and requirements for bracing. Adjunctive treatments to augment the effect of BoNT-A include electrical muscle stimulation of the injected muscles and stretching. When determining suitability for injection, the patient's main goals for intervention need to be established. Muscle overactivity must be distinguished from contracture, and the effect of underlying muscle weakness taken into account. Explanation of the injection process, potential adverse effects and post-injection interventions is essential. Assessment at baseline and post-treatment of impairments such as hypertonia, range of motion and muscle spasm are appropriate; however, the Goal Attainment Scale and other validated patient-centred scales can also be useful to assess therapy outcomes. In the future, initiatives should be directed towards examining the effectiveness of BoNT treatment to assist with achievement of functional and participation goals in adults with hypertonia and dystonia affecting the lower limb.

Cost-effectiveness modeling of intrathecal baclofen therapy versus other interventions for disabling spasticity.

OBJECTIVE: To assess by simulation the cost-effectiveness of intrathecal baclofen (ITB) therapy compared with conventional medical treatments for patients with disabling spasticity and functional dependence caused by any neurological disease. METHODS: Two models were created to simulate therapeutic strategies for managing severe spasticity, one with and one without the use of ITB, to assess various treatment sequences over 2 years based on current medical practices in France. Successful treatment at each evaluation was defined as a combination of: (1) the increased patient and caregiver satisfaction as assessed by goal attainment scaling (GAS), and (2) a decrease of at least 1 point on the Ashworth score. Probabilistic sensitivity analyses were performed using 5000 Monte-Carlo simulations taking into account specific distribution curves for direct costs and effectiveness parameters in each treatment option. RESULTS: The model simulations suggest that including ITB as a first option strategy in the management of function of severely impaired patients with disabling spasticity results in a higher success rate (78.7% vs 59.3%; P < .001). In addition, the ITB therapy model revealed a lower cost (pound 59,391 vs pound 88,272; P < .001) and an overall more favorable cost-effectiveness ratio (pound 75,204/success vs pound 148,822/success; P < .001), compared with conventional medical management without ITB. CONCLUSION: Within the assumptions of our modeling, ITB therapy evaluated by a combination of treatment success criteria at 6-month intervals over a 2-year period may be a cost-effective strategy compared to conventional medical management alone.

Clinical value of botulinum toxin in neurological indications.

Botulinum toxin type-A (BoNT-A) prevents the release of acetylcholine at cholinergic junctions, thereby causing temporary muscle weakness lasting 3-4 months. It is now widely used to treat a broad range of clinical disorders characterized by muscle hyperactivity. BoNT-A has proved effective in the management of several neurological conditions and, in particular, in the management of movement disorders (e.g. blepharospasm, cervical dystonia, laryngeal dystonia, limb dystonia, hemifacial spasm, focal tics, tremor and other hyperkinetic disorders). As a treatment of spasticity, BoNT-A can improve mobility and dexterity as well as preventing the development of distressing and costly secondary complications. In cerebral palsy, BoNT-A is of value, being able to delay or even avoid surgery until motion patterns have become established.

A randomized, double-blind, placebo-controlled, dose-ranging study to compare the efficacy and safety of three doses of botulinum toxin type A (Dysport) with placebo in upper limb spasticity after stroke.

BACKGROUND AND PURPOSE: We sought to define an effective and safe dose of botulinum toxin type A (Dysport) for the treatment of upper limb muscle spasticity due to stroke. METHODS: This was a prospective, randomized, double-blind, placebo-controlled, dose-ranging study. Patients received either a placebo or 1 of 3 doses of Dysport (500, 1000, 1500 U) into 5 muscles of the affected arm. Efficacy was assessed periodically by the Modified Ashworth Scale and a battery of functional outcome measures. RESULTS: Eighty-three patients were recruited, and 82 completed the study. The 4 study groups were comparable at baseline with respect to their demographic characteristics and severity of spasticity. All doses of Dysport studied showed a significant reduction from baseline of muscle tone compared with placebo. However, the effect on functional disability was not statistically significant and was best at a dose of 1000 U. There were no statistically significant differences between the groups in the incidence of adverse events. CONCLUSIONS: The present study suggests that treatment with Dysport reduces muscle tone in patients with poststroke upper limb spasticity. Treatment was effective at doses of Dysport of 500, 1000, and 1500 U. The optimal dose for treatment of patients with residual voluntary movements in the upper limb appears to be 1000 U. Dysport is safe in the doses used in this study.

Fetus papyraceus in twin pregnancy.

Three cases of fetus papyraceus in twin pregnancy were seen over a 4-month period. They were associated with an antepartum stillbirth and intrauterine growth retardation of the larger twin. Two of the 3 mothers exhibited hypertension. It is concluded, therefore, that the appearance of a fetus papyraceus frequently indicates the presence of a hostile intrauterine environment. We suggest that serial ultrasonic examinations be performed to confirm the diagnosis of fetus papyraceus. In this way, appropriate therapy may be directed toward a better outcome for the second twin.

Endometriosis in adolescents.

Traditional gynecologic opinion holds that endometriosis is rare in teenagers. However, several reports of this disease in teenagers have appeared over the past four decades, and in one study of a series of endometriosis patients, teenagers accounted for 8.5% of them. With these facts in mind, 43 consecutive laparoscopies were prospectively analyzed in symptomatic teenagers. A 65% incidence of endometriosis was found. The symptoms and physical findings are analyzed. The liberal use of diagnostic laparoscopy in selected symptomatic adolescents is recommended for the early diagnosis and aggressive preventive treatment of this common and potentially crippling illness.

The management of pain in spasticity.

Pain is a common feature of spasticity and muscle spasms and the reasons for this are discussed in this article. However, the causes of this spasticity have to be determined and for successful management, knowing the underlying mechanisms, which produce spasticity, is necessary. In addition to knowing the range of available treatments, one has to know their particular contribution to the overall management of the patient. The assessment and management of the spastic patient is multi-disciplinary and painful spasticity changes over time. This therefore requires repeated assessments and the direction of the treatment may also change. Pain may be a dominant feature, but is rarely the sole symptom. This article looks at a strategy for the overall management of the patient with the focus on managing pain.

Short-term sequelae of minor head injury (6 years experience of minor head injury clinic).

PURPOSE: It is known that post-concussive symptoms may persist after mild head injury. However, the majority of those patients are denied follow-up or support. A minor head injury clinic was thus established in North Staffordshire Hospital in 1993 to address these problems. METHODS: Patients 16-65 years old attending hospital with minor head injury were invited to attend the clinic two weeks after presentation. A specialized brain injury nurse and/or assistant clinical psychologist assessed them. Patients with persistent symptoms were invited to a second assessment four weeks later. RESULTS: One thousand two hundred and fifty-five patients were invited for first assessment, the most common cause of head injury was assault (454) followed by road traffic accident (334). Six hundred and sixteen patients did not attend the first assessment; most of non-attendees were those who had been assaulted (281). Six hundred and thirty-nine patients attended, (472) were male, their mean age was 33. Forty-three per cent of them had history of recent alcohol intake. One third had had a previous head injury. Although 391 attendees were in regular employment, 219 patients were unable to return to work 2 weeks after discharge (56%), and 49 people were still off sick 6 weeks after the injury. The most common complaints at both assessments were fatigue, headache, dizziness, irritability, sleep disturbances, poor concentration and poor memory in that order. CONCLUSION: This study shows a significant number of patients with minor head injury still complaining of post concussive symptoms, which may contribute to a delay in return to work. The high incidence of non-attendance among the assaulted victims may indicate that this group needs to be more effectively targeted. Further study to look at the longer-term consequences of minor head injury is required in view of these findings.

Spasticity treatment with botulinum toxins.

Spasticity is a physiological consequence of an insult to the brain or spinal cord, which can lead to life-threatening, disabling and costly consequences. This typically occurs following stroke, brain injury, spinal cord injury, multiple sclerosis and other disabling neurological diseases and cerebral palsy. It is but one feature of the upper motor neurone syndrome and there have been considerable developments in its management through new drugs and technology. The sole indication for treating spasticity is when it is causing harm and interferes with active or passive functioning. Successful treatment strategies have now been developed and there is good evidence of treatment effectiveness. Treatment is essentially aimed at reducing abnormal sensory inputs, which have an impact on excessive and uncontrolled alpha-motor neuron activity. Attending to the physical characteristics of muscle shortening is the basis of spasticity management. All pharmacological interventions are adjunctive to a programme of physical intervention and there is a good evidence base for this in relation to botulinum toxin treatment. Management therefore centres around the development of a formal treatment plan is important to document the intended outcomes, which should be written and agreed upon with the patient. Anti-spastic drugs treat spasticity. They do not treat contractures and they will not make hemiplegic limbs function, unless the patient's function is impeded by the spasticity. The management of spasticity is physical and all pharmacological interventions are adjunctive to that. This article therefore deals with the principles of management of spasticity and treatment with botulinum toxin. It covers treatment planning, patient assessment, goal setting and covers the range of available treatments. It also describes how botulinum toxin works, the evidence for its use in spasticity management and practical aspects of treatment, such as muscle location, the injection procedure and post-injection care. Finally, there is a word on the organisation of services. The contribution of botulinum toxin to spasticity management is now well recognised. The trick in clinical management is to use it intelligently and to know when and when not to use it. It is a useful short-term means of improving patients' function and the distressing features of spasticity following an insult to the central nervous system. This is usually against the background of a long-term condition, for which a long-term management strategy is required. Botulinum toxin provides a window of opportunity to improve the outcomes from physical management of the focal and multi-focal problems of spasticity.

A randomized controlled trial of botulinum toxin on lower limb spasticity following acute acquired severe brain injury.

OBJECTIVE: To determine whether serial casting combined with botulinum toxin reduces the development of calf contracture after severe head injury. DESIGN: A double-blind placebo-controlled trial of three parallel treatments for lower limb spasticity. SETTING: Acute general hospital in the UK. SUBJECTS: Adults aged 17-70 years admitted to hospital following a severe brain INTERVENTIONS: Current physical treatment (group I), lower leg casting plus injections with either saline (group II), or with botulinum toxin (group III) into gastrocnemius and soleus muscles. MEASURES: Limit of ankle dorsiflexion at entry and exit after up to 12 weeks, the Glasgow Outcome Scale (GOS) and Modified Ashworth Scale (MAS). RESULTS: Two hundred and fifty-three patients were screened and 35 were entered into the trial. Three patients died and four failed to complete the trial. Eighty-eight per cent of those entering the randomized part of the study developed spasticity within 14 days of their injury and the mean range of improvement in the angle of passive ankle dorsiflexion was 4.59 degrees in controls, 11.69 degrees in cast and saline and 13.59 degrees in cast and botulinum toxin. There were significant improvements in the MAS scores in actively treated groups, but not in controls. Cast and botulinum toxin patients also demonstrated a significant improvement in the GOS. CONCLUSIONS: Active intervention with casting prevents talipes equinovarus deformities in patients losing ankle movement following severe brain injury. Casting alone in these patients is sufficient; the role of additional botulinum toxin needs further investigation, but is safe in these patients.

A summary of spasticity management--a treatment algorithm.

The muscle overactivity seen in spasticity results in limb stiffness and muscle spasm, to which there is both a neurogenic and a biomechanical component. Spasticity does not always cause harm and can assist in the rehabilitation process enabling a patient to stand when their limb weakness would not otherwise allow it. When it does cause harm, however, treatment is required. This aims to (i) prevent provocative factors (ii) treat muscle overactivity; and (iii) prevent complications. Untreated, limb contracture, pain and other complications occur and early management can be most effective. Treatment is essentially physical, but, when this is inadequate, pharmacological intervention may be required. A strategy has been devised which shows that the first choice pharmacological treatment of focal spasticity is botulinum toxin. Over the past decade, the choice of treatment has become more ambitious with the establishment of new technologies. Good management now depends on an understanding of their role and application in relation to the needs of individual patients. To this end, a treatment algorithm which covers the salient facts in patient assessment and gives the indications for the range of available treatments, is the best approach. The indications and limitations of the available treatments are discussed, along with their place in the overall management of the patients. The evidence base for much of what is done is not strong and this summary examines the activities of proven value and of consensus view.