Cost-effectiveness of eculizumab and efgartigimod for the treatment of anti-acetylcholine receptor antibody-positive generalized myasthenia gravis.

BACKGROUND: Eculizumab and efgartigimod were approved to treat anti-acetylcholine receptor antibody-positive generalized myasthenia gravis (anti-AChR Ab-positive gMG). These relatively new biological treatments provide a more rapid onset of action and improved efficacy compared with conventional immunosuppressive treatments, but at a higher cost. OBJECTIVE: To assess the cost-effectiveness of eculizumab and, separately, efgartigimod, each added to conventional therapy vs conventional therapy alone, among patients with refractory anti-AChR Ab-positive gMG and those with anti-AChR Ab-positive gMG, respectively. METHODS: A Markov model with 4 health states was developed, evaluating costs and utility with a 4-week cycle length and lifetime time horizon from a health care system perspective and a modified societal perspective including productivity losses from patients and caregiver burden. Model inputs were informed by key clinical trials and relevant publications identified from targeted literature reviews, and drug costs were identified from Micromedex Red Book. Costs and outcomes were discounted at 3% per year. Incremental cost-effectiveness ratios (ICERs; cost per quality-adjusted life-year [QALY] gained) were calculated for each comparison. RESULTS: Among the corresponding populations, lifetime costs and QALYs, respectively, for eculizumab were $5,515,000 and 11.85, and for conventional therapy, $308,000 and 10.29, resulting in an ICER of $3,338,000/QALY gained. For efgartigimod, lifetime costs and QALYs, respectively, were $6,773,000 and 13.22, and for conventional therapy, $322,000 and 9.98, yielding an ICER of $1,987,000/QALY gained. After applying indirect costs in a modified societal perspective, the ICERs were reduced to $3,310,000/QALY gained for eculizumab and $1,959,000/QALY gained for efgartigimod. CONCLUSIONS: Eculizumab and efgartigimod are rapidly acting and effective treatments for myasthenia gravis. However, at their current price, both therapies greatly exceeded common cost-effectiveness thresholds, likely limiting patient access to these therapies.

Dermal exposure to synthetic musks: Human health risk assessment, mechanism, and control strategy.

Synthetic musks (SMs) have been widely used as odor additives in personal care products (PCPs). Dermal exposure to SMs is the main pathway of the accumulation of these chemicals in human kerateins and poses potential health risks. In this study, in silico methods were established to reduce the human health risk of SMs from dermal exposure by investigating the risk mechanisms, designing lower bioaccumulation ability SMs and suggesting proper PCP ingredients using molecular docking, molecular dynamics simulation, and quantitative structure-activity relationship (QSAR) models. The binding energy, a parameter reflecting the binding ability of SMs and human keratin protein (4ZRY), was used as the indicator to assess the human health risk of SMs. According to the mechanism analysis, total energy was found as the most influential molecular structural feature influencing the bioaccumulation ability of a SM, and as one of the main factors influencing the function (i.e., odor sensitivity) of an SM. The 3D-QSAR models were constructed to control the human health risk of SMs by designing lower-risk SMs derivatives. The phantolide (PHAN)- 58 was determined to be the optimum SM derivative with lower bioaccumulation ability (reduced 17.25%) and improved odor sensitivity (increased 7.91%). A further reduction of bioaccumulation ability of PHAN-58 was found when adding proper body wash ingredients (i.e., alkyl ethoxylate sulfate (AES), dimethyloldimethyl (DMDM), EDTA-Na4, ethylene glycol distearate (EGDS), hydroxyethyl cellulose (HEC), lemon yellow and octyl glucose), leading to a significant reduction of the bioaccumulation ability (42.27%) compared with that of PHAN. Results demonstrated that the proposed theoretical mechanism and control strategies could effectively reduce the human health risk of SMs from dermal exposure.

Nomogram for short-term outcome assessment in AChR subtype generalized myasthenia gravis.

BACKGROUND: An accurate prediction for prognosis can help in guiding the therapeutic options and optimizing the trial design for generalized myasthenia gravis (gMG). We aimed to develop and validate a predictive nomogram to assess the short-term outcome in patients with the anti-acetylcholine receptor (AChR) subtype gMG. METHODS: We retrospectively reviewed 165 patients with AChR subtype gMG who were immunotherapy naïve at the first visit from five tertiary centers in China. The short-term clinical outcome is defined as the achievement of minimal symptom expression (MSE) at 12 months. Of them, 120 gMG patients from Huashan Hospital were enrolled to form a derivation cohort (n = 96) and a temporal validation cohort (n = 24) for the nomogram. Then, this nomogram was externally validated using 45 immunotherapy naïve AChR subtype gMG from the other four hospitals. Multivariate logistic regression was used to screen independent factors and construct the nomogram. RESULTS: MSE was achieved in 70 (72.9%), 20 (83.3%), and 33 (73.3%) patients in the training, temporal validation, and external validation cohort, respectively. The duration ≤ 12 months (p = 0.021), ocular score ≤ 2 (p = 0.006), QMG score > 13 (p = 0.008), and gross motor score ≤ 9 (p = 0.006) were statistically associated with MSE in AChR subtype gMG. The nomogram has good performance in predicting MSE as the concordance indexes are 0.81 (95% CI, 0.72-0.90) in the development cohort, 0.944 (95% CI, 0.83-1.00) in the temporal validation cohort, and 0.773 (95% CI, 0.63-0.92) in the external validation cohort. CONCLUSION: The nomogram achieved an optimal prediction of MSE in AChR subtype gMG patients using the baseline clinical characters.

Exame de dosagem de anticorpo anti-receptor de acetilcolina para diagnóstico da Miastenia Gravis / Examination of anti-receptor antibody dosage acetylcholine for the diagnosis of Myasthenia Gravis

INTRODUÇÃO: A MG é uma doença autoimune da junção neuromuscular que se apresenta com fraqueza muscular localizada ou generalizada. Na maioria dos casos, a doença é causada por anticorpos contra receptores de acetilcolina (anti-AChR), que estão presentes em cerca de 85% e 50% dos pacientes com as formas generalizadas e ocular, respectivamente. O diagnóstico de MG é definido de acordo com manifestações clínicas, além de provas sorológicas ou eletroneuromiográficas, que apresentam sensibilidade e especificidade variadas de acordo com a apresentação da doença. A estimulação nervosa repetitiva é o estudo eletroneuromiográfico complementar atualmente disponível no Sistema Único de Saúde (SUS) para diagnóstico de MG. TECNOLOGIA: Dosagem de anticorpo anti-receptor de acetilcolina. PERGUNTA: o exame diagnóstico de dosagem de anticorpos anti-acetilcolina pode ser uma alternativa à eletroneuromiografia (estimulação nervosa repetitiva ­ ENR) para o diagnóstico da MG? EVIDÊNCIAS CIENTÍFICAS: Uma revisão sistemática (RS) e dois estudos clínicos prospectivos de avaliação de métodos diagnósticos de MG foram incluídos. A RS incluiu sete estudos de avaliação de anticorpos anti-AChR e sete estudos de avaliação da ENR. As estimativas de acurácia do anti-AChR na RS foram agrupadas de acordo com o delineamento dos estudos, evidenciando sensibilidade de 44% a 66% na MG ocular e de 90% a 96% na MG generalizada, sem variação na especificidade (98% a 99% em ambas as apresentações). Os estudos da ENR foram muitos heterogêneos e evidenciaram sensibilidade entre 11% a 39% no diagnóstico da MG ocular, e entre 32% a 98% na MG generalizada, com especificidade elevada em ambos os casos (94% a 97%). Os estudos individuais evidenciaram sensibilidade de 73% a 74% para MG generalizada e de 38% a 70% para MG ocular para o anti-AChR, e sensibilidade de 80% a 83% para MG generalizada e de 45% a 62% para MG ocular. As avaliações do risco de viés dos estudos incluídos demonstraram alto risco de viés para a RS e baixo risco para a maioria dos domínios avaliados nos estudos de coorte. AVALIAÇÃO DE IMPACTO ORÇAMENTÁRIO: A estimativa de custo global anual do exame anti-AChR no cenário base foi de aproximadamente 155 mil reais, com impacto cumulativo em 5 anos de 788 mil reais. Considerando que uma parcela dos indivíduos necessitará submeter-se adicionalmente ao exame eletroneuromiográfico, o que implicaria em aproximadamente 15 mil reais a mais por ano, o custo total do diagnóstico da doença foi de cerca de 170 mil reais a mais por ano, e de cerca de 867 mil reais ao final do quinto ano de incorporação. Na análise de sensibilidade, foram observados valores de custo total de 165 mil reais no cenário mais otimista e acima de 2 milhões de reais no cenário mais pessimista, para o diagnóstico de MG no período de 5 anos. A variável de maior impacto nos resultados foi a população inicial, seguida do custo do exame anti-AChR. CONSIDERAÇÕES FINAIS: A dosagem de anticorpos anti-AChR é um exame confirmatório essencial para diagnóstico de MG. De maneira geral, os estudos evidenciam sensibilidade superior à ENR, tanto no diagnóstico da forma ocular quanto generalizada da doença, com elevada especificidade. Os estudos de ENR foram heterogêneos e evidenciaram diferentes níveis de acurácia de acordo com o número e localização dos estímulos avaliados, o que não ocorre no cenário da dosagem de anticorpos. As avaliações do risco de viés dos estudos incluídos demonstraram alto risco de viés para a RS e baixo risco para a maioria dos domínios avaliados nos estudos de coorte. Não foram identificadas recomendações de diagnóstico de MG em agências de ATS, mas diretrizes internacionais recomendam o exame como etapa inicial no diagnóstico da doença. RECOMENDAÇÃO PRELIMINAR: A Conitec, em sua 93ª reunião ordinária, realizada no dia 08 de dezembro de 2020, deliberou que a matéria fosse disponibilizada em consulta pública com recomendação preliminar favorável à incorporação do exame de dosagem de anticorpos anti-acetilcolina para diagnóstico da Miastenia Gravis no Sistema Único de Saúde. Considerouse, entre outros fatores, que, o exame de avaliação de anticorpos anti-AChR possui uma maior sensibilidade diagnóstica em comparação ao exame eletroneuromiográfico, além disso eletroneuromiografia é um exame demorado e requer um treinamento específico para sua realização. Consequentemente, o tratamento precoce da miastenia gravis poderia ser comprometido. CONSULTA PÚBLICA: A consulta pública nº 68 ficou vigente entre os dias 05/01/2021 e 25/01/2021. Foram recebidas nove contribuições, sendo cinco pelo formulário para contribuições técnico-científicas e quatro pelo formulário para contribuições sobre experiência ou opinião. Estas foram provenientes de pacientes, familiares, amigos ou cuidadores de pacientes, profissionais de saúde ou pessoas interessadas no tema. A maioria das contribuições (77,8%) concordou com a recomendação preliminar da Conitec. Uma contribuição foi neutra (nem concorda e nem discorda) e uma contribuição discordou da recomendação preliminar da Conitec, no entanto, ambas estas contribuições não apresentaram justificativa. As contribuições abordaram, principalmente, os pontos positivos da incorporação da dosagem de anticorpos anti-AChR para o diagnóstico de MG. Não foram solicitadas alterações no texto ou apresentadas referências ou anexos. Houve apenas um argumento sobre a possibilidade de inclusão de anti MUSK para melhoria do atendimento dos demais casos negativos do anticorpo anti-receptor de acetilcolina. Porém, como não houve uma demanda ou pergunta de pesquisa priorizada no escopo, a tecnologia não foi avaliada formalmente pela Conitec. RECOMENDAÇÃO FINAL: Os membros da Conitec presentes na 95ª reunião ordinária, no dia 03 de março de 2021, consideraram que o procedimento possui um corpo de evidências que favorece o exame de dosagem de anticorpos antiacetilcolina para diagnóstico da Miastenia Gravis. Considerou-se a maior sensibilidade e facilidade deste exame comparado à eletroneuromiografia. Diante do exposto, o Plenário deliberou por unanimidade recomendar a incorporação do exame de dosagem de anticorpo anti-receptor de acetilcolina para diagnóstico de Miastenia Gravis. Foi assinado o Registro de Deliberação nº 593/2021. DECISÃO: incorporar o exame de dosagem de anticorpo antirreceptor de acetilcolina para diagnóstico de Miastenia Gravis, do Sistema Único de Saúde - SUS, conforme Portaria nº 11, publicada no Diário Oficial da União nº 74, seção 1, página 235, em 19 de abril de 2021.

Assessment of false transmitters as treatments for nerve agent poisoning.

Nerve agents inhibit acetylcholinesterase (AChE), leading to a build-up of acetylcholine (ACh) and overstimulation at cholinergic synapses. Current post-exposure nerve agent treatment includes atropine to treat overstimulation at muscarinic synapses, a benzodiazepine anti-convulsant, and an oxime to restore the function of AChE. Aside from the oxime, the components do not act directly to reduce the overstimulation at nicotinic synapses. The false transmitters acetylmonoethylcholine (AMECh) and acetyldiethylcholine (ADECh) are analogs of ACh, synthesised similarly at synapses. AMECh and ADECh are partial agonists, with reduced activity compared to ACh, so it was hypothesised the false transmitters could reduce overstimulation. Synthetic routes to AMECh and ADECh, and their precursors, monoethylcholine (MECh) and diethylcholine (DECh), were devised, allowing them to be produced easily on a laboratory-scale. The mechanism of action of the false transmitters was investigated in vitro. AMECh acted as a partial agonist at human muscarinic (M1 and M3) and muscle-type nicotinic receptors, and ADECh was a partial agonist only at certain muscarinic subtypes. Their precursors acted as antagonists at muscle-type nicotinic, but not muscarinic receptors. Administration of MECh and DECh improved neuromuscular function in the soman-exposed guinea-pig hemi-diaphragm preparation. False transmitters may therefore help reduce nerve agent induced overstimulation at cholinergic synapses.

10-year-outcomes after rituximab for myasthenia gravis: Efficacy, safety, costs of inhospital care, and impact on childbearing potential.

Rituximab (RTX) has emerged as an attractive off-label treatment option for patients with myasthenia gravis (MG) refractory to other immune therapies. However, data on long-term outcome after RTX for MG are still scarce. Here we present the 10-year outcomes [median (range) 10.1 (6.7-11.2) years] with respect to efficacy, safety, costs of inhospital care, and impact on childbearing potential in all four MG patients treated by one of the authors with RTX. In all patients, RTX led to sustained clinical improvement and eventual tapering of other immune therapies. RTX was well tolerated, and complications were not observed. After the start of RTX, annual costs for hospital admissions were markedly reduced compared to costs in the year preceding RTX. Under close clinical observation, two patients had uncomplicated pregnancies giving birth to a healthy child. With regard to its efficacy, excellent tolerance, lack of complications, low frequency of repeat infusions and pending patent expiry in many countries, RTX appears to compare favourably with other immune therapies used for MG. Multicentre trials and registries are urgently needed to further address long-term safety issues and clarify the efficacy and role of RTX in managing MG.

Infant acetylcholine, dopamine, and melatonin dysregulation: Neonatal biomarkers and causal factors for ASD and ADHD phenotypes.

Autism spectrum disorders (ASD) and ADHD are common neurodevelopmental disorders that benefit from early intervention but currently suffer from late detection and diagnosis: neurochemical dysregulations are extant already at birth but clinical phenotypes are not distinguishable until preschool age or later. The vast heterogeneity between subjects' phenotypes relates to interaction between multiple unknown factors, making research on factor causality insurmountable. To unlock this situation we pose the hypothesis that atypical pupillary light responses from rods, cones, and the recently discovered ipRGC system reflect early acetylcholine, melatonin, and dopamine dysregulation that are sufficient but not necessary factors for developing ASD and/or ADHD disorders. Current technology allows non-invasive cost-efficient assessment already from the first postnatal month. The benefits of the current proposal are: identification of clinical subgroups based on cause rather than phenotypes; facilitation of research on other causal factors; neonatal prediction of later diagnoses; and guidance for targeted therapeutical intervention.

Assessment of physical fatigability and fatigue perception in myasthenia gravis.

INTRODUCTION: Fatigue includes both performance fatigability and fatigue perception. METHODS: In 32 stable patients with generalized myasthenia gravis (MG) and 17 controls, time-dependent physical performance was assessed by the arm movement test (AMT) and 6-minute walk test (6MWT). MG patients presented with low quantitative MG scores (mean 0.5, SD 0.5) and without pathologic decrement. Fatigability was based on calculation of linear trend (LT) reflecting dynamic performance within subsequent constant time intervals. Perception of physical fatigue was analyzed using fatigue questionnaires. RESULTS: MG patients showed a negative LT in both AMT and 6MWT, significantly differing from stable performance in controls. LT inversely correlated with elevation of acetylcholine receptor antibodies (r = -0.59, P < 0.005) but not with quantitative MG score and fatigue perception. CONCLUSIONS: LT allows quantification of fatigability as an objective measurement of decline in individual performance, even in patients without obvious neuromuscular deficits in routine testing. The missing correlation of experienced fatigue supports the multidimensional fatigue model. Muscle Nerve 55: 657-663, 2017.

Guidelines for pre-clinical assessment of the acetylcholine receptor--specific passive transfer myasthenia gravis model-Recommendations for methods and experimental designs.

Antibodies against the muscle acetylcholine receptor (AChR) are the most common cause of myasthenia gravis (MG). Passive transfer of AChR antibodies from MG patients into animals reproduces key features of human disease, including antigenic modulation of the AChR, complement-mediated damage of the neuromuscular junction, and muscle weakness. Similarly, AChR antibodies generated by active immunization in experimental autoimmune MG models can subsequently be passively transferred to other animals and induce weakness. The passive transfer model is useful to test therapeutic strategies aimed at the effector mechanism of the autoantibodies. Here we summarize published and unpublished experience using the AChR passive transfer MG model in mice, rats and rhesus monkeys, and give recommendations for the design of preclinical studies in order to facilitate translation of positive and negative results to improve MG therapies.

Utilidad de la identificación de los anticuerpos contra receptores de acetil colina para el diagnóstico de miastenia gravis / Utility of the identification of antibodies against acetylcholine receptors for the diagnosis of myasthenia gravis

INTRODUCCIÓN: la Miastenia Gravis es una enfermedad autoinmune, caracteriza por debilidad y fatiga muscular, es fluctuante en su sintomatología, aunado a ello existen dos formas generales de Miastenia, la presentación ocular y la generalizada. No todos los pacientes son seropositivos a la identificación de anticuerpos contra receptores de acetil colina (AChR-ab), estas características hacen que la confirmación diagnóstica sea un reto clínico, y se consideren diferentes pruebas diagnósticas. OBJETIVO: realizar una revisión, apreciación crítica y síntesis de la evidencia disponible sobre la validez y utilidad de la identificación de AChR-ab para el diagnóstico de Miastenia Gravis. METODOLOGÍA: la evaluación fue realizada de acuerdo con un protocolo definido a priori por el grupo desarrollador. Se realizó una búsqueda sistemática en MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, LILACS y Google, sin restricciones de idioma, fecha de publicación y tipo de estudio. Las búsquedas electrónicas fueron hechas en septiembre de 2014 y se complementaron mediante búsqueda manual en bola de nieve y una consulta con expertos temáticos. La tamización de referencias se realizó por dos revisores de forma independiente y los desacuerdos fueron resueltos por consenso. La selección de estudios fue realizada mediante la revisión en texto completo de las referencias preseleccionadas, verificando los criterios de elegibilidad predefinidos. Las características y hallazgos de los estudios fueron extraídos a partir de las publicaciones originales. Se realizó un análisis estadístico descriptivo. RESULTADOS: Se identificó una revisión sistemática de análisis descriptivo que evalúa la identificación de AChR-ab, SFEMG, RNS, comparados con el diagnóstico clínico, de calidad media, con una calidad individual de los estudios baja predominantemente, también se identificaron dos estudios primarios de tipo cohortes prospectiva que evaluaron la misma comparación y uno de ellos (1992) comparó los diferentes test en pacientes con un resultado previo negativo, para estos estudios el riesgo global de sesgo fue bajo. La identificación de AChR-ab comparado con el diagnóstico clínico (características clínicas y prueba de respuesta a colinesterásicos) presenta una buena sensibilidad y especificad, que se encuentra en los siguientes rangos para MG 0.90 -0.96 y 0.99 respectivamente; para MO una sensibilidad y especificidad de 0.44-0.66 y 0.98 -0.99 respectivamente. La sensibilidad y especificad reportada para la SFEMG comparada con diagnóstico clínico (características clínicas y prueba de respuesta a colinesterásicos), se encuentra en los rangos de 86% - 93% y 63% - 83%, respectivamente, reportados para MO y Miastenia. Se evidencia en la literatura variabilidad en la sensibilidad ye especificidad, derivada del tipo de musculo y el electrodo usado, lo anterior no permitió realizar análisis combinados del efecto dada la alta heterogeneidad entre los estudios primarios. En el caso de la RNS, la sensibilidad y la especificidad se encuentran en los siguientes rangos, para MO 29% a 77% y 94%, y para MG 79% a 80% y 97%, para MO el rango es amplio debido a la alta heterogeneidad entre los estudios. En el caso de pacientes seronegativos (AChR-ab negativos), se reporta una sensibilidad para la SFEMG de 97% y para RNS de 66%. Cuando los pacientes son positivos ante la identificación de AChR-ab, la sensibilidad de la SFEMG y la RNS disminuye a 80% y 61% respectivamente. No se encontraron estudios que reportaran la sensibilidad y especificidad de otros anticuerpos como: MuSK, anti RLP4 y receptores de sodio. CONCLUSIONES: en pacientes con sospecha de Miastenia Gravis, la identificación de AChR-ab tiene una buena sensibilidad y especificidad, especialmente para los casos de Miastenia Generalizada. La electromiografía de fibra unitaria (SFEMG) reportó mejores rangos de sensibilidad y especificidad que la identificación de AChR-ab y la estimulación repetitiva del nervio (RNS), cuando se comparan con diagnóstico clínico. En el caso de pacientes seronegativos (AChR-ab negativos), la SFEMG, tuvo la mejor sensibilidad. No se encontraron estudios que reportaran la sensibilidad y especificidad de otros anticuerpos como: MuSK, anti RLP4 y receptores de sodio.(AU)

Novel future therapeutic options in myasthenia gravis.

BACKGROUND: Myasthenia Gravis (MG) is an autoimmune disease caused by complement-fixing antibodies against the acetylcholine receptors (AChR). Antigen-specific CD4+ T cells, Tregs and Th17+ are also necessary. Consequently, antibodies, B cells, molecules associated with signalling pathways on T helper cells, cytokines and complement are targets for more specific treatment options. OBJECTIVES: Because available immunosuppressive therapies cause unacceptable side effects after long-term use or are not always effective in inducing remission, novel biological agents directed against the following targets might be options for future therapies in MG: 1) T cell Intracellular Signaling Pathways associated with T cell activation, such as monoclonal antibodies against CD52, Interleukin 2-receptor (IL-2 R), co-stimulatory molecules or compounds inhibiting Janus tyrosine kinases JAK1, JAK3; 2) B cells, against key B cell-surface molecules or trophic factors B cell activation factor (BAFF) and a proliferating inducing ligand (APRIL); 3) Complement, against C3 or C5 that intercept membranolytic attack complex formation; 4) Cytokines and cytokine receptors, including IL-6, IL-17, the p40 subunit of IL12/1L-23, and GM-CSF; and 5) Lymphocyte migration molecules. Construction of recombinant AChR antibodies that block the binding of the pathogenic antibodies, can be a future molecular tool. CONCLUSION: New biological agents are in the offing for future therapies in MG. Their efficacy needs to be secured with vigorously controlled clinical trials and weighted against excessive cost and rare complications.

Non-neurological and metabolic side effects in the Cost Utility of the Latest Antipsychotics in Schizophrenia Randomised Controlled Trial (CUtLASS-1).

The impact of non-neurological and metabolic side effects (NNSEs) on the prescription of antipsychotics in real clinical practice remains unclear. We conducted an intention-to-treat, secondary analysis of data from a randomised, controlled trial (CUtLASS-1; n=227) to examine NNSEs emergent at 12 weeks and 52 weeks. A clinically significant difference was defined as double or half the symptoms in groups prescribed first- versus second-generation antipsychotics, represented by odds ratios greater than 2.0 (indicating advantage for first-generation drugs) or less than 0.5 (indicating advantage for the newer drugs). There were no differences between the treatment groups at baseline. At both 12 and 52 weeks follow-up, patients on second-generation drugs were more likely than their first-generation counterparts to experience cardiovascular problems and anticholinergic side effects, as well as increased sexual side effects in men. Objective weight gain was equivalent between the two groups at 12 weeks, but by one year fewer patients in the second-generation arm experienced weight gain and there was no significant difference with regard to percent change in BMI. These results suggest that there may be clinically significant increases in anticholinergic, cardiovascular, and sexual side effects for patients on second-generation drugs. The expected increased weight gain in the second-generation arm did not occur. This study provides evidence that clinicians should take a more nuanced approach toward expert antipsychotic prescription, rather than viewing the drugs as distinct classes.

DockoMatic: automated peptide analog creation for high throughput virtual screening.

The purpose of this manuscript is threefold: (1) to describe an update to DockoMatic that allows the user to generate cyclic peptide analog structure files based on protein database (pdb) files, (2) to test the accuracy of the peptide analog structure generation utility, and (3) to evaluate the high throughput capacity of DockoMatic. The DockoMatic graphical user interface interfaces with the software program Treepack to create user defined peptide analogs. To validate this approach, DockoMatic produced cyclic peptide analogs were tested for three-dimensional structure consistency and binding affinity against four experimentally determined peptide structure files available in the Research Collaboratory for Structural Bioinformatics database. The peptides used to evaluate this new functionality were alpha-conotoxins ImI, PnIA, and their published analogs. Peptide analogs were generated by DockoMatic and tested for their ability to bind to X-ray crystal structure models of the acetylcholine binding protein originating from Aplysia californica. The results, consisting of more than 300 simulations, demonstrate that DockoMatic predicts the binding energy of peptide structures to within 3.5 kcal mol(-1), and the orientation of bound ligand compares to within 1.8 Å root mean square deviation for ligand structures as compared to experimental data. Evaluation of high throughput virtual screening capacity demonstrated that Dockomatic can collect, evaluate, and summarize the output of 10,000 AutoDock jobs in less than 2 hours of computational time, while 100,000 jobs requires approximately 15 hours and 1,000,000 jobs is estimated to take up to a week.

Sistema colinérgico: revisitando receptores, regulação e a relação com a doença de Alzheimer, esquizofrenia, epilepsia e tabagismo: [revisão] / Colinergic system: revisiting receptors, regulation and the relationship with Alzheimer disease, schizophrenia, epilepsy and smoking: [review]

OBJETIVO: Revisar a estrutura e o funcionamento do sistema colinérgico central ressaltando seu papel na fisiologia e na fisiopatologia das doenças de Alzheimer e Parkinson, esquizofrenia, epilepsia e tabagismo. MÉTODO: Foi realizada uma pesquisa bibliográfica no MedLine, LILACS, PubMed e ISI, e na Biblioteca da Fundação Oswaldo Cruz, RJ, selecionando-se o período de 1914 a 2009, utilizando os descritores: "receptors", "cholinergic", "Alzheimer disease", "schizophrenia", "epilepsy" e "smoking", além de referências cruzadas dos artigos selecionados e análise adicional de referências na literatura específica do tema. RESULTADOS: Efeitos importantes da ativação de receptores colinérgicos nicotínicos e muscarínicos sobre o desenvolvimento do sistema nervoso central (SNC) têm sido descritos. A dessensibilização e a internalização dos receptores acoplados à proteína G mediadas pela ativação de proteínas cinases têm sido descritas em proliferação, diferenciação e morte celular, além de síndromes neuropsiquiátricas. CONCLUSÃO: As informações produzidas a partir de estudos do sistema de neurotransmissão colinérgica podem auxiliar no desenvolvimento de medicamentos mais específicos para o tratamento da doença de Alzheimer, esquizofrenia, epilepsia e tabagismo.

OBJECTIVES: To review articles regarding important topics about cholinergic system and its ionotropic and G-protein coupled receptors as well as their regulation, also enlightening its importance in central nervous system (CNS) development and in several neuropsychiatric conditions such as Alzheimer disease, schizophrenia, epilepsy and smoking. METHOD: Bibliographical research was completed through MedLine, LILACS, PubMed, ISI and the Fundação Oswaldo Cruz Library, RJ, specifically for 1914 to 2009, using the descritors: "receptors", "cholinergic", Alzheimer "disease", "schizophrenia", "epilepsy" and "smoking", in addition to the cross-reference of the articles selected and further analyses of bibliographical references on the theme. RESULTS: Currently literature describes important effects of nicotinic and muscarinic receptors activation on development of central nervous system (CNS). The protein G coupled receptors dessensibilization and internalization mediated by kinases have been described in proliferation, differentiation and cell death, and also in neurologic disorders. DISCUSSION: The importance of the cholinergic system and its relationship with pathologies such as Alzheimer disease, schizophrenia, epilepsy is evident. The data produced so far may help on planning medicaments more specific for these pathologies treatment.

An energy-efficient gating mechanism in the acetylcholine receptor channel suggested by molecular and Brownian dynamics.

Acetylcholine receptors mediate electrical signaling between nerve and muscle by opening and closing a transmembrane ion conductive pore. Molecular and Brownian dynamics simulations are used to shed light on the location and mechanism of the channel gate. Four separate 5 ns molecular dynamics simulations are carried out on the imaged structure of the channel, a hypothetical open structure with a slightly wider pore and a mutant structure in which a central ring of hydrophobic residues is replaced by polar groups. Water is found to partially evacuate the pore during molecular simulations of the imaged structure, whereas ions face a large energy barrier and do not conduct through the channel in Brownian dynamics simulations. The pore appears to be in a closed configuration despite containing an unobstructed pathway across the membrane as a series of hydrophobic residues in the center of the channel provide an unfavorable home to water and ions. When the channel is widened slightly, water floods into the channel and ions conduct at a rate comparable to the currents measured experimentally in open channels. The pore remains permeable to ions provided the extracellular end of the pore-lining helix is restrained near the putative open configuration to mimic the presence of the ligand binding domain. Replacing some of the hydrophobic residues with polar ones decreases the barrier for ion permeation but does not result in significant currents. The channel is posited to utilize an energy efficient gating mechanism in which only minor conformational changes of the hydrophobic region of the pore are required to create macroscopic changes in conductance.

Quantitative myasthenia gravis score: assessment of responsiveness and longitudinal validity.

We prospectively tested the quantitative myasthenia gravis score (QMG) for responsiveness and longitudinal construct validity in 53 patients with myasthenia gravis. Index of responsiveness was high. Longitudinal construct validity was confirmed by the correlation between changes in QMG and manual muscle testing and by a difference in QMG changes across patients that were clinically unchanged, improved, or worse between two visits. Our results support QMG use for assessing clinical change in trials.

Maximum likelihood estimation of ion channel kinetics from macroscopic currents.

We describe a maximum likelihood method for direct estimation of rate constants from macroscopic ion channel data for kinetic models of arbitrary size and topology. The number of channels in the preparation, and the mean and standard deviation of the unitary current can be estimated, and a priori constraints can be imposed on rate constants. The method allows for arbitrary stimulation protocols, including stimuli with finite rise time, trains of ligand or voltage steps, and global fitting across different experimental conditions. The initial state occupancies can be optimized from the fit kinetics. Utilizing arbitrary stimulation protocols and using the mean and the variance of the current reduce or eliminate problems of model identifiability (Kienker, 1989). The algorithm is faster than a recent method that uses the full autocovariance matrix (Celentano and Hawkes, 2004), in part due to the analytical calculation of the likelihood gradients. We tested the method with simulated data and with real macroscopic currents from acetylcholine receptors, elicited in response to brief pulses of carbachol. Given appropriate stimulation protocols, our method chose a reasonable model size and topology.

Interactions of the M2delta segment of the acetylcholine receptor with lipid bilayers: a continuum-solvent model study.

M2delta, one of the transmembrane segments of the nicotinic acetylcholine receptor, is a 23-amino-acid peptide, frequently used as a model for peptide-membrane interactions. In this and the companion article we describe studies of M2delta-membrane interactions, using two different computational approaches. In the present work, we used continuum-solvent model calculations to investigate key thermodynamic aspects of its interactions with lipid bilayers. M2delta was represented in atomic detail and the bilayer was represented as a hydrophobic slab embedded in a structureless aqueous phase. Our calculations show that the transmembrane orientation is the most favorable orientation of the peptide in the bilayer, in good agreement with both experimental and computational data. Moreover, our calculations produced the free energy of association of M2delta with the lipid bilayer, which, to our knowledge, has not been reported to date. The calculations included 10 structures of M2delta, determined by nuclear magnetic resonance in dodecylphosphocholine micelles. All the structures were found to be stable inside the lipid bilayer, although their water-to-membrane transfer free energies differed by as much as 12 kT. Although most of the structures were roughly linear, a single structure had a kink in its central region. Interestingly, this structure was found to be the most stable inside the lipid bilayer, in agreement with molecular dynamics simulations of the peptide and with the recently determined structure of the intact receptor. Our analysis showed that the kink reduced the polarity of the peptide in its central region by allowing the electrostatic masking of the Gln13 side chain in that area. Our calculations also showed a tendency for the membrane to deform in response to peptide insertion, as has been previously found for the membrane-active peptides alamethicin and gramicidin. The results are compared to Monte Carlo simulations of the peptide-membrane system, as presented in the accompanying article.

In vitro EROD induction equivalency factors for the 10 PAHs generally monitored in risk assessment studies in The Netherlands.

The ethoxy resorufin dealkylase (EROD) inducing potency of 10 polycyclic aromatic hydrocarbons (PAHs) is measured in the H4IIE in vitro bioassay and the results are compared to those reported in literature. The selected PAHs varied considerably in their potency to induce EROD activity. Anthracene (Ant) and phenanthrene (Phe) showed consistently no response. Naphthalene (Nap) showed no or a very weak response on EROD activity. Fluoranthene (Fla) and benzo[g,h,i]perylene (BghiP) showed weak responses at the highest doses. The other PAHs, including indeno[1,2,3-cd]pyrene (IP), benz[a]anthracene (BaA), benzo[a]pyrene (BaP), chrysene (Chr) and benzo[k]fluoranthene (BkF), showed full bell shaped dose-response curves. BaP EROD induction equivalency factors (BaP-1EF) were calculated and increased in the order Ant approximately Phe < Fla < Nap < BghiP < IP < BaA < BaP < Chr < BkF. Comparison of BaP-IEFs based on 50% effect concentration (EC50) or lowest effect concentration (LEC), yielded a significant relationship between both methods described by the equation log(BaPIEF(EC50) = 0.55 x log(BaPIEF(LEC)) + 0.07 (r2 = 0.913). BaP-IEFs as derived from our measurements and as reported in literature and measured in other in vitro assays deviated up to a factor of 17 among the different studies, but the potency rankings were comparable. For the PAH mixture as on average present in the human diet an overall tetrachlorodibenzo-p-dioxin (TCDD)-IEF of 1 x 10(-4) was estimated. The total PAH based TCDD induction equivalents (IEQ) intake then was calculated 300 pg/day, which is approximately 2 times higher then the PHAH based TCDD-EQ intake reported for humans.