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On March 11, 2020, the World Health Organization declared the new Coronavirus a pandemic, due to the large number of cases and deaths worldwide. The upper inhalation routes are the gateway for any viral variant, with the installation of SAR-CoV-2 in the respiratory epithelium, which, belonging to the Coronovidae family, has an acidic pH. Alkalization is a way to destabilize the pathophysiology of COVID-19. In this way, the introduction of saline solutions into the upper respiratory system would be a way of interfering with the symptomatology and behavior of the virus. Objective: To evaluate the role of inhaled 3% sodium bicarbonate solution in improving respiratory symptoms and destabilizing SAR-CoV-2 in COVID-19. Materials and methods: Randomized clinical trial, with people diagnosed with COVID-19 through the RT-PCR assay. The participants included were of any age and gender undergoing hospital treatment at the COVID-19 ward unit at the Hospital Regional Doutor Estácio Muniz, located in the municipality of Aquidauana in the State of Mato Grosso do Sul, between September/2020 and November/2021. Results: It was observed that moderate/severe patients who received inhaled treatment with a 3% sodium bicarbonate solution had a good prognosis for their respiratory condition, progressing to hospital discharge. Conclusion: Treatment with sodium bicarbonate solution has a high potential in the treatment as an adjunct to COVID-19.

Introduction: Gynecological cancers are among the most common in women worldwide, with cervical cancer (CC) being the most frequent type and considered an important public health problem. Methodology: This is a descriptive, cross-sectional, observational study with a quantitative approach, in which 76 women who were being treated for CC in 2020 were interviewed through a questionnaire. The data were entered and reviewed in a program spreadsheet editor and analyzed in a statistical program, where the absolute and relative frequencies of the variables of interest were calculated. Results: It was observed that 27.6% of the women were between 41 and 50 years old, 72.4% were brown, 35.5% had not completed elementary school, 53.9% were married or in a stable relationship, 43.4% had a paid job and 56.6% had a monthly family income of one minimum wage, with 38.2% having menarche at the age of 12 years or less, 65.8% reported their first sexual intercourse at 16 or more years of age, 48.7% had five or more pregnancies, 55.3% had no history of miscarriage, 64.5% used or are using hormonal contraceptives, 60.5% did not undergo regular Pap smear tests and 58.82% had a diagnosis of CC at an advanced stage. Conclusion: Socioeconomic vulnerability, early onset of sexual life, multiparity, low adherence to the preventive examination and diagnosis at na advanced stage were the main characteristics of patients affected by CC.

A utilização da nebulização com solução alcalina de bicarbonato de sódio seria uma opção para possivelmente prevenir a infecção da COVID-19, haja vista o contexto da pandemia e a incessante busca por um tratamento. Esta pesquisa objetiva descrever e elencar os sintomas de um grupo de pacientes que realizaram a nebulização com solução de sódio no período de pandemia da COVID 19. Trata-se de um estudo com análise descritiva dos sintomas e intercorrências clínicas de pacientes de um mesmo grupo familiar com a utilização da solução de bicarbonato de sódio em combate à disseminação do vírus Sars-CoV-2. Durante os primeiros 14 dias de nebulização, o único sintoma apresentado por um componente do grupo familiar foi de cefaléia. Conclui-se que a combinação de hábitos saudáveis, isolamento social e alcalinização das vias aéreas tem potencial de proteção sólido para contaminação e atenuação da infecção pelo SARS-CoV-2.

Introdução: A Lombalgia é um agravo que afeta 11,9% da população economicamente ativa mundial, e os Cirurgiões Dentistas devido às longas jornadas de trabalho, sedentarismo, obesidade e a não observância do ideal ergonômico à profissão, estão dentro desse percentual. Conhecida por causar do desconforto lombar, esse agravo se manifesta na forma limitante dos movimentos músculos-esqueléticos, prejudicando a vida profissional e social dos pacientes. Objetivo: Identificar a frequência de Lombalgia em Cirurgiões Dentistas que atuam na atenção primária em saúde pública do município de Rio Branco/Acre, bem como, descrever e analisar o perfil epidemiológico desses profissionais. Método: Trata-se de uma pesquisa de campo de abordagem quali-quantitativa, realizada em 2018. Obedecendo ao critério de exclusão, apenas 30 Unidades de Saúde, dentro de um total de 59 postos de trabalho, receberam a visita dos pesquisadores. Resultados: Destacou-se a presença de lombalgia em 53,33%, cuja média de idade em anos está entre 41 mulheres e 42,81 para mulheres, apresentando média de IMC de 26 Kg/m2 apontando para um resultado levemente acima do peso, média de horas trabalhadas semanalmente é de 41,87 para os homens e de 42,85 para as mulheres. Conclusão: A respeito dos achados clínicos, chegou-se a conclusão de que a lombalgia está relacionada a diversos fatores, com destaques para a ergonomia, tempo de profissão e carga horária. Assim, é importante o autocuidado e a prevenção desse agravo, recomenda-se que novos estudos sejam realizados afim de se obter mais informações sobre a problemática.

Introdução: A rápida disseminação do vírus SARS-CoV-2 e suas variantes levou a uma pandemia global desenvolvendo a síndrome respiratória aguda grave nos pacientes rapidamente. A doença coronavírus 2019 (COVID-19) apresenta um espectro de sintomas que variam de leve a grave, onde requer a admissão na unidade de terapia intensiva (UTI). A síndrome do desconforto respiratório agudo é uma complicação importante em pacientes com doença COVID-19 grave, sendo que um dos agravantes é que não há terapias farmacológicas reconhecidas para COVID-19. A rápida disseminação da COVID-19 levou a um aumento na taxa de hospitalizações e admissões em UTI sobrecarregando o sistema de saúde no Brasil e em todo o mundo. A alta demanda de utilização de sedativos, analgésicos e bloqueadores neuromusculares foram utilizados no atendimento de pacientes com COVID-19 sob ventilação mecânica. Objetivo: Identificar os principais trabalhos relacionados à sedação mais utilizados no tratamento de COVID-19 em pacientes adultos em terapia intensiva. Metodologia: Este trabalho de revisão sistemática da literatura, onde as buscas foram realizadas entre agosto a outubro de 2021, na base de dados do Pubmed e Scielo. Os descritores utilizados foram: “COVID-19”, “Síndrome respiratória aguda”, “Sedação” e “Farmacologia”. Inicialmente foram encontrados 296 artigos e, após a análise dos resumos e da aplicação dos critérios de inclusão e exclusão, 90 artigos foram selecionados. Por fim, os estudos foram submetidos à análise quantitativa e qualitativa, resultando em 24 artigos que estão incluídos nesta revisão sistemática. Resultados: Em pacientes com a COVID-19 os mesmos devem permanecer com nível superficial de sedação. As indicações de sedação profunda, para este perfil de pacientes são: Pacientes com síndrome do desconforto respiratório agudo grave e/ou com necessidade de curarização em mudanças de decúbitos, devendo ser sedados de acordo com a escala de RASS. Conclusão: Mediante as variantes do SARS-COV-2 estarem em constante aparecimento e o início da quarta onda no mundo faz necessário mais estudos e ensaios clínicos para verificar o melhor protocolo individual para os pacientes com COVID-19.

Introduction: This study aimed to evaluate the use of sodium bicarbonate solution as an adjunct in the treatment of pediatric patients with moderate symptoms through nebulization. Methods: Two matched groups were followed, of which 2 received treatment with sodium bicarbonate solution along with conventional treatment and 2 patients used saline solution plus conventional treatment. Results: Pulmonary auscultation was better in snoring and crackles in patients treated with sodium bicarbonate solution compared to patients treated with saline. Radiological findings, decreased opacity and bilateral consolidations, as well as reduced length of hospital stay (increase) were observed in patients treated with sodium bicarbonate solution. Conclusion: The use of sodium bicarbonate solution as an adjunct in the treatment of COVID-19 improved the prognosis compared to conventional treatment in pediatric patients.

INTRODUÇÃO: Em 17 de março de 2020, o estado do Acre registrou os três primeiros casos confirmados na capital Rio Branco, sendo decretado o lockdown (20 de março) como medida para evitar a disseminação do SARS-CoV-2 em municípios e aldeias indígenas. Os 3 primeiros casos notificados no alto rio Juruá no dia 4 de abril, mobilizaram toda a equipe do DSEI para o enfrentamento do COVID-19. METODOLOGIA: Dentre os sintomas que mais levam o paciente a deixar a aldeia e procurar atendimento médico em hospitais de campanha está o desconforto respiratório ou dispneia. Relatamos aqui a redução da dispneia pelo uso de nebulização com solução de bicarbonato de sódio a 3% (NaHCO3 3%), em pacientes indígenas no Estado do Acre, Amazônia Ocidental. Por conveniência, foram selecionados 20 pacientes indígenas, positivos para SARS-CoV-2, que apresentavam a dispneia, casos moderados, independentemente do sexo e idade, foram analisados. Esses pacientes foram divididos em dois grupos, um tratado com a solução e o outro controle não tratado. RESULTADOS: O grupo de tratamento nebulizou com 10ml de solução de NaHCO3 a 3% por 20 minutos, a cada 6h, por 7 dias consecutivos. A saturação periférica de oxigênio (SpO2%) foi medida por oxímetro de pulso, antes e após cada nebulização. Para a análise dos dados paramétricos, utilizou o teste de comparação com a média entre os grupos e o teste t pareado para comparar as médias dos dependentes. Para dados não paramétricos, o teste dos postos sinalizados de Wilcoxon foi usado a um nível de significância de 0,05. Verificou-se que os dez participantes do grupo tratado com a solução relataram melhora da dispneia e aumento da SpO2% nos dias 2, 3 e 4, após nebulizações com a solução. CONCLUSÃO: Espera-se, com estes resultados, ampliar o estudo para um número maior de participantes, em diferentes condições clínicas e comorbidades, grupos etários, indígenas e não indígenas.

Introduction: This study aimed to evaluate the use of sodium bicarbonate solution as an adjunct in the treatment of critically ill patients in an intensive care unit (ICU). Methods: A group of 76 patients were followed up, of which 44 received treatment with a sodium bicarbonate (NaHCO3) solution along with the conventional treatment, and 32 patients used only the conventional treatment. Results: In patients treated, there was an improvement in radiological findings, a decrease in opacity and bilateral consolidations, as well as reduced length of stay in the ICU, and mortality. Conclusion: The use of NaHCO3 solution as an adjunct in the treatment of COVID-19 improved prognosis compared to conventional treatment.

Sepsis survivors show long-term impairments, including alterations in memory and executive function. Evidence suggests that systemic inflammation contributes to the progression of Alzheimeŕs disease (AD), but the mechanisms involved in this process are still unclear. Boosted (trained) and diminished (tolerant) innate immune memory has been described in peripheral immune cells after sepsis. However, the occurrence of long-term innate immune memory in the post-septic brain is fully unexplored. Here, we demonstrate that sepsis causes long-lasting trained innate immune memory in the mouse brain, leading to an increased susceptibility to Aβ oligomers (AβO), central neurotoxins found in AD. Hippocampal microglia from sepsis-surviving mice shift to an amoeboid/phagocytic morphological profile when exposed to low amounts of AβO, and this event was accompanied by the upregulation of several pro-inflammatory proteins (IL-1β, IL-6, INF-γ and P2X7 receptor) in the mouse hippocampus, suggesting that a trained innate immune memory occurs in the brain after sepsis. Brain exposure to low amounts of AβO increased microglial phagocytic ability against hippocampal synapses. Pharmacological blockage of brain phagocytic cells or microglial depletion, using minocycline and colony stimulating factor 1 receptor inhibitor (PLX3397), respectively, prevents cognitive dysfunction induced by AβO in sepsis-surviving mice. Altogether, our findings suggest that sepsis induces a long-lasting trained innate immune memory in the mouse brain, leading to an increased susceptibility to AβO-induced neurotoxicity and cognitive impairment.

INTRODUCAO: As infeccoes respiratorias agudas e cronicas sao um grande problema de saude publica a nivel mundial. Um dos componentes utilizados para tratamento das doencas respiratorias e o bicarbonato de sodio (NaHCO3), sendo uma opcao para tratamento da COVID-19. A associacao entre a COVID-19 e o tratamento do trato respiratorio ainda e pouco documentada, bem como as suas possiveis consequencias. METODOLOGIA: Foi conduzida uma revisao sistematica da literatura. As buscas foram realizadas a partir do mes de agosto de 2020, na base de dados National Library of Medicine (Medline), Scielo e Pubmed. Os descritores utilizados foram: “Doenca Respiratoria” e “Bicarbonato de sodio”. Inicialmente foram encontrados 315 artigos e, apos a analise dos resumos e da aplicacao dos criterios de inclusao e exclusao, 63 artigos foram selecionados. Por fim, os estudos foram submetidos a analise quantitativa e qualitativa, resultando em 24 artigos que estao incluidos nesta revisao sistematica. A escala de sistematizacao PRISMA foi utilizada a fim de aprimorar os resultados desta revisao. RESULTADOS: Os estudos demonstraram que a ocorrencia de manifestacoes respiratorias inclui complicacoes do trato respiratorio superior e inferior podem ser tratados com bicarbonato de sodio. Entretanto, diversos estudos apresentam limitacoes como dificuldade na aplicacao, obtencao de dados, escassez de recursos e curto tempo de acompanhamento.

Neurological complications affecting the central nervous system have been reported in adult patients infected by Zika virus (ZIKV) but the underlying mechanisms remain unknown. Here, we report that ZIKV replicates in human and mouse adult brain tissue, targeting mature neurons. ZIKV preferentially targets memory-related brain regions, inhibits hippocampal long-term potentiation and induces memory impairment in adult mice. TNF-α upregulation, microgliosis and upregulation of complement system proteins, C1q and C3, are induced by ZIKV infection. Microglia are found to engulf hippocampal presynaptic terminals during acute infection. Neutralization of TNF-α signaling, blockage of microglial activation or of C1q/C3 prevent synapse and memory impairment in ZIKV-infected mice. Results suggest that ZIKV induces synapse and memory dysfunction via aberrant activation of TNF-α, microglia and complement. Our findings establish a mechanism by which ZIKV affects the adult brain, and point to the need of evaluating cognitive deficits as a potential comorbidity in ZIKV-infected adults., Here, using ex-vivo human adult cortical tissue and a mouse model, the authors investigate the functional consequences of Zika virus (ZIKV) infection in the adult brain, and show that ZIKV causes synapse damage and altered brain function that impacts cognition via activation of innate and inflammatory factors.

To analyze risk factors for death in individuals with severe acute respiratory syndrome due to COVID-19.This was a retrospective cohort study, comprised of adult individuals with COVID-19, from March to September 2020, notified by the Epidemiological Surveillance System in the state of Acre, Brazil. Cox regression was used.Among 57,700 individuals analyzed, the incidence was 2,765.4/100,000 inhabitants, and mortality was, 61.8/100,000 inhabitants. The risk factors for death were: being male (HR=1.48 -95% CI 1.25;1.76), age ≥60 years (HR=10.64 -95% CI 8.84;12.81), symptom of dyspnea (HR=4.20 -95% CI 3.44;5.12) and multimorbidity (HR=2.23 -95% CI 1.77;2.81), with emphasis on heart disease and diabetes mellitus. 'Sore throat' and 'headache' were symptoms present in mild cases of COVID-19.Being male, elderly, having heart disease, diabetes mellitus and dyspnea were characteristics associated with death due to COVID-19.Analisar fatores de risco para óbito em indivíduos com síndrome respiratória aguda grave por COVID-19.Coorte retrospectiva, constituída de indivíduos adultos com COVID-19, de março a setembro de 2020, notificados pelo sistema de vigilância epidemiológica do estado do Acre, Brasil. Empregou-se regressão de Cox.Entre 57.700 indivíduos analisados, a incidência foi de 2.765,4/100 mil habitantes, e a mortalidade, de 61,8/100 mil hab. Os fatores de risco para o óbito foram ser do sexo masculino (HR=1,48 - IC95% 1,25;1,76), ter idade ≥60 anos (HR=10,64 - IC95% 8,84;12,81), sintoma de dispneia (HR=4,20 - IC95% 3,44;5,12) e apresentar multimorbidade (HR=2,23 - IC95% 1,77;2,81), com destaque para cardiopatas e diabetes mellitus. Os sintomas ‘dor de garganta’ e ‘cefaleia’ estavam presentes nos casos leves da doença.Ser homem, idoso, apresentar cardiopatia, diabetes mellitus e dispneia foram características associadas ao óbito pela COVID-19.Analizar los factores de riesgo de muerte en individuos con Síndrome Respiratorio Agudo Grave por COVID-19.Cohorte retrospectiva, con individuos adultos con COVID-19, entre marzo y septiembre 2020, notificado pelo Sistema de Vigilancia Epidemiológica en el estado de Acre, Brasil. Se utilizó la regresión de Cox.57.700 individuos evaluados, la incidencia fue de 2.765,4/100.000 habitantes y la mortalidad 61,8/100.000 habitantes. Los factores de riesgo de muerte fueron: sexo masculino (HR=1,48 - IC95% 1,25;1,76), edad ≥60 años (HR=10,64 - IC95% 8,84;12,81), disnea (HR=4,20 - IC95% 3,44;5,12), multimorbidad (HR=2,23 - IC95% 1,77;2,81), incluidos problemas cardíacos y diabetes. Los síntomas dolor de garganta y de cabeza estuvieron presentes en casos leves de la enfermedad.Hombres, ancianos, personas com enfermedades cardíacas, diabetes y disnea fueron características asociadas com la muerte por COVID-19.

Nitric oxide (NO) contributes to myogenesis by regulating the transition between myoblast proliferation and fusion through cGMP signaling. NO can form S-nitrosothiols (RSNO), which control signaling pathways in many different cell types. However, neither the role of RSNO content nor its regulation by the denitrosylase activity of S-nitrosoglutathione reductase (GSNOR) during myogenesis is understood. Here, we used primary cultures of chick embryonic skeletal muscle cells to investigate whether changes in intracellular RSNO alter proliferation and fusion of myoblasts in the presence and absence of cGMP. Cultures were grown to fuse most of the myoblasts into myotubes, with and without S-nitrosocysteine (CysNO), 8-Br-cGMP, DETA-NO, or inhibitors for NO synthase (NOS), GSNOR, soluble guanylyl cyclase (sGC), or a combination of these, followed by analysis of GSNOR activity, protein expression, RSNO, cGMP, and cell morphology. Although the activity of GSNOR increased progressively over 72 h, inhibiting GSNOR (by GSNOR inhibitor – GSNORi – or by knocking down GSNOR with siRNA) produced an increase in RSNO and in the number of myoblasts and fibroblasts, accompanied by a decrease in myoblast fusion index. This was also detected with CysNO supplementation. Enhanced myoblast number was proportional to GSNOR inhibition. Effects of the GSNORi and GSNOR knockdown were blunted by NOS inhibition, suggesting their dependence on NO synthesis. Interestingly, GSNORi and GSNOR knockdown reversed the attenuated proliferation obtained with sGC inhibition in myoblasts, but not in fibroblasts. Hence myoblast proliferation is enhanced by increasing RSNO, and regulated by GSNOR activity, independently of cGMP production and signaling.

OBJECTIVES: To describe the nutritional status of children with cancer during hospital admission in the five different regions of Brazil by Pediatric subjective global nutritional assessment (PSGNA). METHODS: A multicenter, cross-sectional study part of the Brazilian Survey on Oncological Nutrition in Pediatrics (IBNOPe). Patients of both sexes, aged between 2 and 18 years, diagnosed of cancer under treatment in institutions of all regions of Brazil, from March to December of 2018, were eligible. Data were collected from the medical records, using a form prepared exclusively for this research. For subjective nutritional evaluation, the PSGNA questionnaire, adapted by Saraiva et al (2017) for children with cancer, was applied within 48 hours of hospital admission. The classification was made in well nourished, moderately malnourished and severely malnourished. Participating Institutions received training prior to the implementation of the research. Descriptive statistics were performed for statistical analysis. RESULTS: A total of 579 patients were evaluated, 3.3% (n = 19) from the north, 33.0% (n = 191), 20.9% (n = 121) 30) west-west and 37.6% (n = 218) southeast. According to PSGNA data at admission 66.3% were well nourished, 33.7% were malnourished (27.2%) or severely malnourished (6.5%). Considering the region, the southeast presented a higher percentage of severely malnourished children (8.5%), according to the PSGNA. According to anthropometric data, about 23.5% of children presented inadequate anthropometric nutritional status (Zscore

Objetivo: Descrever sobre o papel do marcador tumoral CA 125 mediante o diagnóstico de carcinoma de ovário. Métodos: Este estudo é uma revisão integrativa, na qual foram realizados levantamentos bibliográficos e análises de aproximadamente 15 artigos em periódicos científicos encontrados nas bases de dados: MEDLINE, LILACS, SCIELO, BIREME e PubMed, no período de 2011 a 2021. Nesta revisão foram incluídos estudos que se concentraram em abordar os tipos de marcadores tumorais (evidenciando CA 125 e MUC 16). Resultados: A neoplasia epitelial maligna do ovário é evidente entre os tipos de tumores de malignidade agressiva que acometem o aparelho reprodutor feminino, por se tratar de uma doença de difícil controle. Dessa forma, a sobrevida desses pacientes está bem abaixo das demais, sendo de suma importância o diagnóstico precoce. O biomarcador CA125 foi considerado como tendo um alto nível de sensibilidade. Considerações Finais: O biomarcador sérico CA125 é incapaz de confirmar diagnóstico sozinho, pois se altera com outras doença benignas, porém é muito utilizado na prática clínica para auxilio no diagnostico de câncer de ovário.

OBJECTIVES: To evaluate the influence of nutritional status on admission, according to the anthropometric indicator (Body Mass Index- BMI), serum C-reactive protein (CRP) and albumin on length of hospital stay (LHS) and time of mechanical ventilation (MV) in the Pediatric Intensive Care Unit (PICU) in a Oncological Treatment Center. METHODS: It is a longitudinal retrospective study with all children admitted to the PICU in 2013. The comparison of medians related to LHS and VM was assessed using the nonparametric Mann-Whitney and Kruskal Wallis test. The Kaplan-Meier curve evaluated the influence of body mass index (BMI), CRP and albumin on LHS and VM. The significance value was P

Skeletal myogenesis comprises myoblast replication and differentiation into striated multinucleated myotubes. Agents that interfere with myoblast replication are important tools for the understanding of myogenesis. Recently, we showed that cholesterol depletion by methyl-β-cyclodextrin (MCD) enhances the differentiation step in chick-cultured myogenic cells, involving the activation of the Wnt/β-catenin signaling pathway. However, the effects of cholesterol depletion on myoblast replication have not been carefully studied. Here we show that MCD treatment increases cell proliferation in primary chick myogenic cell cultures. Treatment of myogenic cells with the anti-mitotic reagent cytosine arabinoside, immediately following cholesterol depletion, blocks the MCD-induced effects on proliferation. Cholesterol depletion induced an increase in the number of desmin-positive mononucleated cells, and an increase in desmin expression. MCD induces an increase in the expression of the cell cycle regulator p53 and the master switch gene MyoD1. Treatment with BIO, a specific inhibitor of GSK3β, induced effects similar to MCD on cell proliferation; while treatment with Dkk1, a specific inhibitor of the Wnt/β-catenin pathway, neutralized the effects of MCD. These findings indicate that rapid changes in the cholesterol content in cell membranes of myoblasts can induce cell proliferation, possibly by the activation of the Wnt/β-catenin signaling pathway.

The success of peripheral nerve regeneration depends on intrinsic properties of neurons and a favorable environment, although the mechanisms underlying the molecular events during degeneration and regeneration are still not elucidated. Schwann cells are considered one of the best candidates to be closely involved in the success of peripheral nerve regeneration. These cells and invading macrophages are responsible for clearing myelin and axon debris, creating an appropriate route for a successful regeneration. After injury, Schwann cells express galectin-3, and this has been correlated with phagocytosis; also, in the presence of galectin-3, there is inhibition of Schwann-cell proliferation in vitro. In the present study we explored, in vivo, the effects of the absence of galectin-3 on Wallerian degeneration and nerve-fiber regeneration. We crushed the sciatic nerves of galectin-3 knockout and wild-type mice, and followed the pattern of degeneration and regeneration from 24 h up to 3 weeks. We analyzed the number of myelinated fibers, axon area, fiber area, myelin area, G-ratio and immunofluorescence for beta-catenin, macrophages and Schwann cells in DAPI counterstained sections. Galectin-3 knockout mice showed earlier functional recovery and faster regeneration than the wild-type animals. We concluded that the absence of galectin-3 allowed faster regeneration, which may be associated with increased growth of Schwann cells and expression of beta-catenin. This would favor neuron survival, followed by faster myelination, culminating in a better morphological and functional outcome.

The multifunctional protein Lmo7 has been implicated in some aspects of myogenesis in mammals. Here we studied the distribution and expression of Lmo7 and the effects of Lmo7 knockdown in primary cultures of chick skeletal muscle cells. Lmo7 was localized within the nuclei of myoblasts and at the perinuclear region of myotubes. Knockdown of Lmo7 using siRNA specific to chick reduces the number and width of myotubes and the number of MyoD positive-myoblasts. Both Wnt3a enriched medium and Bio, activators of the Wnt/beta-catenin pathway, could rescue the effects of the Lmo7 knockdown suggesting a crosstalk between the Wnt/beta-catenin and Lmo7-mediated signaling pathways. Our data shows a role of Lmo7 during the initial events of chick skeletal myogenesis, particularly in myoblast survival.

International audience; Myoblasts undergo a series of changes in the composition and dynamics of their plasma membranes during the initial steps of skeletal muscle differentiation. These changes are crucial requirements for myoblast fusion and allow the formation of striated muscle fibers. Membrane microdomains, or lipid rafts, have been implicated in myoblast fusion. Flotillins are scaffold proteins that are essential for the formation and dynamics of lipid rafts. Flotillins have been widely studied over the last few years, but still little is known about their role during skeletal muscle differentiation. In the present study, we analyzed the expression and distribution of flotillin-2 in chick, mice and human muscle cells grown in vitro. Primary cultures of chick myogenic cells showed a decrease in the expression of flotillin-2 during the first 72 hours of muscle differentiation. Interestingly, flotillin-2 was found to be highly expressed in chick myogenic fibroblasts and weakly expressed in chick myoblasts and multinucleated myotubes. Flotillin-2 was distributed in vesicle-like structures within the cytoplasm of chick myogenic fibroblasts, in the mouse C2C12 myogenic cell line, and in neonatal human muscle cells. Cryo-immunogold labeling revealed the presence of flotillin-2 in vesicles and in Golgi stacks in chick myogenic fibroblasts. Further, brefeldin A induced a major reduction in the number of flotillin-2 containing vesicles which correlates to a decrease in myoblast fusion. These results suggest the involvement of flotillin-2 during the initial steps of skeletal myogenesis.

Therapeutic ultrasound (TU) has been used for the last 50 y in rehabilitation, including treatment of soft tissues. Ultrasound waves can be employed in two different modes of operation, continuous and pulsed, which produce both thermal and non-thermal effects. Despite the large-scale use of TU, there are few scientific studies on its biologic effects during skeletal muscle differentiation. To better analyze the cellular effects of TU, we decided to follow cells in vitro. The main purpose of this study was to evaluate the effects of TU in primary chick myogenic cell cultures using phase contrast optical microscopy and immunofluorescence microscopy, followed by image analysis and quantification. Our results indicate that TU can stimulate the differentiation of skeletal muscle cells in vitro, as measured by the thickness of multinucleated myotubes, the ratio of mononucleated cells to multinucleated cells and expression of the muscle-specific protein desmin. This study is a first step toward a metrologic and science-based protocol for cell treatment under different ultrasound field exposures.

Cardiac cells are organized in vivo in a complex tridimensional structural organization that is crucial for heart function. While in vitro studies can reveal details about cardiac cell biology, usually cells are grown on simplified two-dimensional (2D) environments. To address these differences, we established a cardiac cell culture composed of both 2D and three-dimensional (3D)-organized cells. Our results shows significant differences between the two culture contexts in relation to the overall morphology of the cells, contraction ability, proliferation rate, presence of intercellular adhesion structures, organization of myofibrils, mitochondria morphology, endoplasmic reticulum contents, cytoskeletal filaments and extracellular matrix distribution, and expression of markers of cardiac differentiation. Cardiac cells grown in 2D-context displayed a flattened and well spread shape, were mostly isolated and their cytoplasm was filled with a large network of microfilaments and microtubules. In contrast, 3D-cells were smaller in size, were always in close contact with each other with several cellular junctions, and displayed a less conspicuous cytoskeletal network. 3D-cells had more mitochondria and myofibrils and these cells contract spontaneously more often than 2D-cells. On the other hand, endoplasmic reticulum membranes were present in higher amounts in 2D-cells when compared to 3D-cells. The expression of desmin, cadherin and alpha-actinin was higher in 3D-aggregates compared to 2D-spread cells. These findings indicate that the tridimensional environment in which the cardiac cells are grown influence several aspects of cardiac differentiation, including cell adhesion, cell shape, myofibril assembly, mitochondria contents and protein expression. We suggest that the use of this cardiac culture model, with 2D and 3D-context cells, could be useful for studies on the effects of different drugs, or growth factors, giving valuable information on the biological response of cells grown in different spatial organizations.

Muscle fibers are formed during embryonic development by the fusion of mononucleated myoblasts. The spatial structure and molecular composition of the sarcolemma are crucial for the myoblast recognition and fusion steps. Cyclodextrins are a group of substances that have the ability to solubilize lipids through the formation of molecular inclusion complexes. Previously, we have shown that methyl-β-cyclodextrin (MbCD) enhances muscle differentiation. Here, we analyzed the effects of α-cyclodextrin (aCD) during myogenesis. Myogenic cultures treated with aCD showed an increase in myoblast fusion and in the expression of myogenin, sarcomeric tropomyosin and desmin. aCD-conditioned media accelerates myogenesis in a similar way as aCD does, and increased levels of IL-4 were found in aCD-conditioned media. aCD-induced effects on myogenesis were inhibited by an anti-IL4 antibody. These results show that α-cyclodextrin induces myogenic differentiation by the release of IL-4.

Cholesterol is a sterol lipid that plays pleiotropic roles in the plasma membrane; it is involved in maintaining membrane fluidity and permeability and the structure of lipid microdomains. Despite its importance, the consequences of membrane cholesterol depletion during cardiac differentiation have not been described. Therefore, we investigated the cellular and molecular mechanisms associated with cholesterol depletion in cultures of chick cardiac cells. We used methyl-β-cyclodextrin (MCD) to deplete membrane cholesterol and investigate its role in cardiac differentiation by following the expression of several markers including the transcriptional factor Nkx2.5, the myofibrillar protein tropomyosin, the cytoskeletal intermediate filament protein desmin, the caveolar protein caveolin-3, the cadherin/β-catenin adhesion complex, and the junctional protein connexin 43. Confocal microscopy showed that desmin-positive cells were located more externally in the aggregates in relation to the more internally located caveolin-3-positive cells. Desmin and caveolin-3 were co-localized in filamentous structures in the subsarcolemmal region of well-spread cells outside the aggregates. β-Catenin was concentrated in regions of cell-cell contact, and tropomyosin in sarcomeric structures. Western blot tests showed that immediately following cholesterol depletion, there was a slight decrease in the expression of caveolin-3 and desmin, and at the same time there was a sharp increase in the expression of cadherin, tropomyosin, Nkx2.5 and connexin 43. Further, we found an increase in the expression of cardiac β-myosin heavy chain 7, a marker of the cardiac hypertrophic phenotype. These observations suggest that membrane cholesterol plays a significant role in regulating cardiomyocyte differentiation.