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BACKGROUND: The genotype-by-environment interaction (GxE) in beef cattle can be investigated using reaction norm models to assess environmental sensitivity and, combined with genome-wide association studies (GWAS), to map genomic regions related to animal adaptation. Including genetic markers from whole-genome sequencing in reaction norm (RN) models allows us to identify high-resolution candidate genes across environmental gradients through GWAS. Hence, we performed a GWAS via the RN approach using whole-genome sequencing data, focusing on mapping candidate genes associated with the expression of reproductive and growth traits in Nellore cattle. For this purpose, we used phenotypic data for age at first calving (AFC), scrotal circumference (SC), post-weaning weight gain (PWG), and yearling weight (YW). A total of 20,000 males and 7,159 females genotyped with 770k were imputed to the whole sequence (29 M). After quality control and linkage disequilibrium (LD) pruning, there remained â¼ 2.41 M SNPs for SC, PWG, and YW and â¼ 5.06 M SNPs for AFC. RESULTS: Significant SNPs were identified on Bos taurus autosomes (BTA) 10, 11, 14, 18, 19, 20, 21, 24, 25 and 27 for AFC and on BTA 4, 5 and 8 for SC. For growth traits, significant SNP markers were identified on BTA 3, 5 and 20 for YW and PWG. A total of 56 positional candidate genes were identified for AFC, 9 for SC, 3 for PWG, and 24 for YW. The significant SNPs detected for the reaction norm coefficients in Nellore cattle were found to be associated with growth, adaptative, and reproductive traits. These candidate genes are involved in biological mechanisms related to lipid metabolism, immune response, mitogen-activated protein kinase (MAPK) signaling pathway, and energy and phosphate metabolism. CONCLUSIONS: GWAS results highlighted differences in the physiological processes linked to lipid metabolism, immune response, MAPK signaling pathway, and energy and phosphate metabolism, providing insights into how different environmental conditions interact with specific genes affecting animal adaptation, productivity, and reproductive performance. The shared genomic regions between the intercept and slope are directly implicated in the regulation of growth and reproductive traits in Nellore cattle raised under different environmental conditions.
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Interação Gene-Ambiente , Estudo de Associação Genômica Ampla , Polimorfismo de Nucleotídeo Único , Reprodução , Sequenciamento Completo do Genoma , Animais , Bovinos/genética , Bovinos/crescimento & desenvolvimento , Reprodução/genética , Feminino , Masculino , Genótipo , Fenótipo , Locos de Características Quantitativas , Desequilíbrio de LigaçãoRESUMO
This study utilized Bayesian inference in a genome-wide association study (GWAS) to identify genetic markers associated with traits relevant to the adaptation of Hereford and Braford cattle breeds. We focused on eye pigmentation (EP), weaning hair coat (WHC), yearling hair coat (YHC), and breeding standard (BS). Our dataset comprised 126,290 animals in the pedigree. Out of these, 233 sires were genotyped using high-density (HD) chips, and 3750 animals with medium-density (50 K) single-nucleotide polymorphism (SNP) chips. Employing the Bayes B method with a prior probability of π = 0.99, we identified and tagged single nucleotide polymorphisms (Tag SNPs), ranging from 18 to 117 SNPs depending on the trait. These Tag SNPs facilitated the construction of reduced SNP panels. We then evaluated the predictive accuracy of these panels in comparison to traditional medium-density SNP chips. The accuracy of genomic predictions using these reduced panels varied significantly depending on the clustering method, ranging from 0.13 to 0.65. Additionally, we conducted functional enrichment analysis that found genes associated with the most informative SNP markers in the current study, thereby providing biological insights into the genomic basis of these traits.
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STATEMENT OF PROBLEM: Prefabricated and custom glass fiber posts have been successfully used to reconstruct endodontically treated teeth. However, the performance of computer-aided design and computer-aided manufacture (CAD-CAM) milled glass fiber posts is unclear. PURPOSE: The purpose of this systematic review with meta-analysis was to compare the fracture and bond strength and cement layer thickness of CAD-CAM milled glass fiber posts with prefabricated or custom glass fiber posts. MATERIAL AND METHODS: The protocol was registered in the Open Science Framework (http://osf.io/65jm7). Two reviewers searched the PubMed/MEDLINE, Web of Science, Embase, Scopus, and ProQuest databases for articles up to September 2023. In addition, the reference lists were hand searched. A meta-analysis was performed by using the RevMan 5.4 program. The risk of bias was assessed using the RoBDEMAT tool. RESULTS: After screening, a total of 18 studies were included. The CAD-CAM milled glass fiber posts showed higher fracture strength (P=.02; Standardized Mean Difference [SMD]: 0.57; 95% Confidence Interval [CI]: 0.07 to 1.07), bond strength (P=.010; SMD: 1.07; 95% CI: 0.26 to 1.89), and lower cement layer thickness (P=.009; SMD: -2.94; 95% CI: -5.15 to -0.73) when compared with prefabricated glass fiber posts. However, fracture strength (P=.53; SMD: 0.38; 95% CI: -0.79 to 1.54) and bond strength (P=.90; SMD: -0.05; 95% CI: -0.81 to 0.72) were statistically similar between CAD-CAM milled and custom glass fiber posts. Significant and substantial heterogeneity was observed in all meta-analyzes (P<.01; I>60%). The studies sufficiently reported most domains related to bias, except for randomization of samples, sample size rationale and reporting and operator blinding. CONCLUSIONS: CAD-CAM milled and custom glass fiber posts provide an effective and safe option for restoring endodontically treated teeth, especially for weakened teeth or enlarged root canals. However, further well-designed clinical research is recommended to strengthen these findings.
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This study aimed to evaluate the intestinal interactions between three short-chain fatty acids (SCFA), namely, acetate, propionate, and butyrate, and pathogenic bacteria (Vibrio anguillarum) in intestinal explants of European sea bass (Dicentrarchus labrax) juveniles. The anterior intestine of 12 fish with an average weight of 100 g (killed by excess anesthesia with 2-phenoxyethanol) were sampled and placed in 24-well plates. The experimental treatments consisted of a control medium and a control plus 1 mM or 10 mM of sodium acetate (SA), sodium butyrate (SB), and sodium propionate (SP). After 2 h of incubation, the explants were challenged with Vibrio anguillarum at 1 × 107 CFU/mL for 2 h. After the bacterial challenge, and regardless of the SCFA treatment, the oxidative stress-related genus catalase (cat) and superoxide dismutase (sod) were down-regulated and glutathione peroxidase (gpx) was up-regulated. Furthermore, the immune-related genes, i.e., the tumor necrosis factor (TNF-α), interleukin 8 (IL-8), transforming growth factor (TGF-ß), and nuclear factor (NF-Kß) were also up-regulated, and interleukin 10 (IL-10) was down-regulated. During the pre-challenge, sodium propionate and sodium butyrate seemed to bind the G-protein coupled receptor (grp40L), increasing its expression. During the challenge, citrate synthase (cs) was down-regulated, indicating that the SCFAs were used as an energy source to increase the immune and oxidative responses. Overall, our results suggest that sodium propionate and sodium butyrate may boost European sea bass immune response at the intestine level.
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Lactation curves, which describe the production pattern of milk-related traits over time, provide insightful information about individual cow health, resilience, and milk production efficiency. Key functional traits can be derived through lactation curve modeling, such as lactation peak and persistency. Furthermore, novel traits such as resilience indicators can be derived based on the variability of the deviations of observed milk yield from the expected lactation curve fitted for each animal. Lactation curve parameters are heritable, indicating that one can modify the average lactation curve of a population through selective breeding. Various statistical methods can be used for modeling longitudinal traits. Among them, the use of random regression models enables a more flexible and robust modeling of lactation curves compared with traditional models used to evaluate accumulated milk 305-d yield, as they enable the estimation of both genetic and environmental effects affecting milk production traits over time. In this symposium review, we discuss the importance of evaluating lactation curves from a longitudinal perspective and various statistical and mathematical models used to analyze longitudinal data. We also highlighted the key factors that influence milk production over time, and the potential applications of longitudinal analyses of lactation curves in improving animal health, resilience, and milk production efficiency. Overall, analyzing the longitudinal nature of milk yield will continue to play a crucial role in improving the production efficiency and sustainability of the dairy industry, and the methods and models developed can be easily translated to other longitudinal traits.
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Nipah virus (NiV), a biosafety level 4 agent, was first identified in human clinical cases during an outbreak in 1998 in Malaysia and Singapore. While flying foxes are the primary host and viral vector, the infection is associated with a severe clinical presentation in humans, resulting in a high mortality rate. Therefore, NiV is considered a virus with an elevated epidemic potential which is further underscored by its recent emergence (September 2023) as an outbreak in India. Given the situation, it is paramount to understand the molecular dynamics of the virus to shed more light on its evolution and prevent potential future outbreaks. In this study, we conducted Bayesian phylogenetic analysis on all available NiV complete genomes, including partial N-gene NiV sequences (≥1000 bp) in public databases since the first human case, registered in 1998. We observed the distribution of genomes into three main clades corresponding to the genotypes Malaysia, Bangladesh and India, with the Malaysian clade being the oldest in evolutionary terms. The Bayesian skyline plot showed a recent increase in the viral population size since 2019. Protein analysis showed the presence of specific protein families (Hendra_C) in bats that might keep the infection in an asymptomatic state in bats, which also serve as viral vectors. Our results further indicate a shortage of complete NiV genomes, which would be instrumental in gaining a better understanding of NiV's molecular evolution and preventing future outbreaks. Our investigation also underscores the critical need to strengthen genomic surveillance based on complete NiV genomes that will aid thorough genetic characterization of the circulating NiV strains and the phylogenetic relationships between the henipaviruses. This approach will better prepare us to tackle the challenges posed by the NiV virus and other emerging viruses.
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Quirópteros , Infecções por Henipavirus , Vírus Nipah , Animais , Humanos , Vírus Nipah/genética , Filogenia , Teorema de Bayes , Variação GenéticaRESUMO
Count traits are usually explored in livestock breeding programs, and they usually do not fit into normal distribution, requiring alternatives to adjust the phenotype to estimate accurate genetic parameters and breeding values. Alternatively, distribution such as Poisson can be used to evaluate count traits. This study aimed to compare and discuss the genetic evaluation for oocyte and embryo counts considering Gaussian (untransformed variable - LIN; transformed by logarithm - LOG; transformed by Anscombe - ANS) and Poisson (POI) distributions. The data comprised 11,343 total oocytes (TO), viable oocytes (VO), cleaved embryos (CE), and viable embryo (VE) records of ovum pick-up from 1740 Dairy Gir heifers and cows. The genetic parameters and breeding values were estimated by the MCMCglmm package of the R software. The posterior means of heritability varied from 0.40 (LIN) to 0.49 (POI) for TO, 0.39 (LIN) to 0.49 (POI) for VO, 0.30 (LOG) to 0.41 (POI) for cleaved embryos, and 0.19 (LIN) to 0.32 (POI) for viable embryos. The posterior means of repeatability varied from 0.56 (LIN) to 0.65 (POI) for TO, 0.53 (LOG) to 0.63 (POI) for VO, 0.44 (LOG) to 0.60 (POI) for CE, and 0.36 (LOG) to 0.56 (POI) for VE. Deviance information criterion and mean squared residuals indicated that POI model should be used for the genetic evaluation of embryo and oocyte count traits. Spearman's rank correlation between estimated breeding value (EBV) for embryo and oocyte count traits computed by POI, LOG, and ANS models was high (ranging from 0.77 to 0.99), indicating little reranking among the best animals. The POI model is the most adequate for genetic evaluation, resulting in more reliable EBV of oocyte and embryo count traits for Dairy Gir cattle.
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Teorema de Bayes , Cruzamento , Modelos Genéticos , Oócitos , Animais , Bovinos/genética , Oócitos/crescimento & desenvolvimento , Feminino , Fenótipo , Embrião de Mamíferos , Distribuição de PoissonRESUMO
The pharmacological treatment of epilepsy is often complex due to the lack of efficacy in many patients and profound side effects from current drugs, including sedation, motor impairment, and teratogenesis. In the quest for new antiepileptic drugs, animal venoms offer a valuable source of neuroactive molecules targeting ion channels and neurotransmitter receptors. This study investigates the antiepileptic potential of compounds isolated from the venom of the Parawixia bistriata spider. One compound, designated Parawixin-11, demonstrated significant anticonvulsant effects when injected into the cerebral ventricle in a dose-response manner. It effectively countered seizures induced by bicuculline (ED50 0.16 µg/animal), pentylenetetrazole (ED50 0.08 µg/animal), strychnine (ED50 0.05 µg/animal), pilocarpine (ED50 0.10 µg/animal), and NMDA (ED50 0.008 µg/animal). We also assessed whether intracerebroventricular administration of Parawixin-11 caused motor or cognitive impairments in rats using the open field, rotarod, and Morris water maze tests. No differences in exploration or movement were observed with doses of 0.3, 0.2, or 0.1 µg of Parawixin-11. Although there was an increased latency to find the platform during the acquisition phase of the Morris water maze test, no differences in spatial memory retention were noted. Given Parawixin-11's potency against NMDA-induced seizures, we hypothesize that it may modulate the glutamatergic system, aligning with the mechanisms of several spider-derived polyamines.
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Viral hemorrhagic fever poses a significant public health challenge due to its severe clinical presentation and high mortality rate. The diagnostic process is hindered by similarity of symptoms across different diseases and the broad spectrum of pathogens that can cause hemorrhagic fever. In this study, we applied viral metagenomic analysis to 43 serum samples collected by the Public Health Laboratory (Fundação Ezequiel Dias, FUNED) in Minas Gerais State, Brazil, from patients diagnosed with hemorrhagic fever who had tested negative for the standard local hemorrhagic disease testing panel. This panel includes tests for Dengue virus (DENV) IgM, Zika virus IgM, Chikungunya virus IgM, yellow fever IgM, Hantavirus IgM, Rickettsia rickettsii IgM/IgG, and Leptospira interrogans IgM, in addition to respective molecular tests for these infectious agents. The samples were grouped into 18 pools according to geographic origin and analyzed through next-generation sequencing on the NextSeq 2000 platform. Bioinformatic analysis revealed a prevalent occurrence of commensal viruses across all pools, but, notably, a significant number of reads corresponding to the DENV serotype 2 were identified in one specific pool. Further verification via real-time PCR confirmed the presence of DENV-2 RNA in an index case involving an oncology patient with hemorrhagic fever who had initially tested negative for anti-DENV IgM antibodies, thereby excluding this sample from initial molecular testing. The complete DENV-2 genome isolated from this patient was taxonomically classified within the cosmopolitan genotype that was recently introduced into Brazil. These findings highlight the critical role of considering the patient's clinical condition when deciding upon the most appropriate testing procedures. Additionally, this study showcases the potential of viral metagenomics in pinpointing the viral agents behind hemorrhagic diseases. Future research is needed to assess the practicality of incorporating metagenomics into standard viral diagnostic protocols.
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Human Pegivirus Type 1 (HPgV-1), a ubiquitous commensal virus, has been recently suggested as a marker of immunologic function. There is scarce data for the presence, genotypes, and molecular characteristics of HPgV-1 among kidney transplant recipients. Therefore, the objective of this study was to examine the prevalence and the molecular characteristics (cycle threshold, genotypes) of this viral infection among kidney transplant recipients from the Brasília, Federal District of Brazil. HPgV-1 RNA detection in the plasma was assessed by RT-qPCR. Positive samples were submitted to sequencing and phylogenetic analysis of the 5´-UTR portion of the viral genome. The estimated HPgV-1 prevalence among renal-transplant recipients was 20%. The performed phylogenetic inference revealed that the most frequent genotype among these patients was HPgV-1 genotype 2 (78.9%) presented by its two subgenotypes (2 A and 2B), followed by genotypes 1 and 3 (10.5% each). This study presents new data about the HPgV-1 circulation and molecular characteristics among kidney transplant recipients from the Federal District of Brazil. Further work is fundamental to examine the effect of HPgV-1 among patients with immunological suppression, including kidney transplant recipients.
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Abstract Background Acute myocardial infarction (AMI) without obstructive coronary arteries (MINOCA) is a medical condition of great relevance, with clinical characteristics of AMI, but without evidence of coronary artery obstruction. The mechanism involved in the pathophysiology of the disease and its possible etiologies are important objects of study due to their impact on the morbidity and mortality of affected patients. Objectives The aim of this study was to systematically review MINOCA and its characteristics, with emphasis on the clinical profile of patients, etiology, pathophysiology, diagnosis, and treatment of the syndrome. Methods Relevant articles related to MINOCA were analyzed in the PubMed and LILACS databases. In the initial search stage, 619 eligible articles were obtained, with final inclusion criteria being: original systematic reviews with clinical, epidemiological, diagnostic, or treatment data on MINOCA, published in Portuguese or English, with an abstract, and a publication date limit of September 2020. Results A total of 10 articles classified as systematic reviews that considered clinical data on MINOCA were included in this review. Conclusion After analyzing various literature, the present study provided a tool to better understand MINOCA, not only regarding its casuistry but also in grouping parameters and information that contribute to a healthy approach to this clinical situation. It was possible to identify and better outline the clinical profile of patients who presented this condition and the use of appropriate tools for correct diagnosis and ideal treatment.
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INTRODUCCIÓN: El ataque cerebro vascular (ACV) es una emergencia médica, que ocurre cuando se interrumpe el suministro de sangre al cerebro o cuando existe un sangrado en el cerebro. EL OBJETIVO de esta investigación fue determinar las causas de la no trombolisis en pacientes con ventana terapéutica en accidente cerebral isquémico. MATERIALES Y MÉTODOS: Se realizó un estudio descriptivo con el fin de conocer el argumento de no utilización de tratamiento trombolítico en pacientes dentro de ventana terapéutica en accidente cerebral isquémico que consultaron o fueron derivados al Hospital Clínico Herminda Martín de Chillán, desde octubre de 2017 a marzo de 2018. Se revisaron las fichas clínicas tanto de pacientes egresados vivos como fallecidos. Estas se obtuvieron del Servicio de Neurología, extrayendo la información de Datos de Atención de Urgencias (DAU) y/o ficha clínica. RESULTADOS: Una muestra de 78 pacientes cumplió con los criterios de inclusión del estudio, cuya principal causa de no trombolisis en ventana terapéutica fue presentar un puntaje en la escala de NIHSS menor a 5 puntos, representando el 20,51% del total. DISCUSIÓN: Según la literatura, los principales motivos de exclusión en este grupo de pacientes fueron los ACV con manifestaciones leves (13,1%), mejoría clínica (18,2%) y exclusiones percibidas en el protocolo (13,6%), los cuales coinciden con esta investigación, donde el principal motivo fue un puntaje de NIHSS < 5, manifestando déficit neurológico leve al ingreso. Se recomienda la inclusión del criterio de funcionalidad previa a terapia trombolítica, en este grupo de pacientes. En pacientes en ventana terapéutica con accidente cerebrovascular isquémico atendidos en Hospital Herminda Martín de Chillán.
INTRODUCTION: Vascular brain attack (CVA) is a medical emergency, which occurs when the blood supply to the brain is interrupted or when there is bleeding in the brain. The OBJECTIVE of this research was to determine the causes of non-thrombolysis in patients with therapeutic windows in ischemic stroke. MATERIALS AND METHODS: A descriptive study was carried out in order to know the argument of non-use of thrombolytic treatment in patients with therapeutic window in ischemic stroke who consulted or was referred to the Hospital Clínico Herminda Martín de Chillán Clinical, from October 2017 to March of 2018. The clinical records of both living and deceased patients were reviewed. These were obtained from the Neurology Service, extracting the information from Emergency Care Data (DAU) and / or clinical record. RESULTS: A sample of 78 patients met the inclusion criteria of the study, whose main cause of non-thrombolysis in the therapeutic window was to present a score on the NIHSS scale of less than 5 points, representing 20.51% of the total. DISCUSSION: According to the literature, the main reasons for exclusion in this group of patients were stroke with mild manifestations (13.1%), clinical improvement (18.2%) and perceived exclusions in the protocol (13.6%), which, coincide with this investigation where the main reason was an NIHSS score <5, manifesting mild neurological deficit upon admission. The inclusion of the functionality criterion prior to thrombolytic therapy is recommended in this group of patients.
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Resumo Objetivo: Identificar os principais diagnósticos e características epidemiológicas dos pacientes atendidos em um serviço público de urgência oftalmológica. Métodos: Estudo transversal e retrospectivo, com análise de prontuários de 2834 pacientes atendimentos no período de julho a setembro de 2017, no serviço de Urgência Oftalmológica do Complexo Hospitalar Ouro Verde, Campinas, Brasil. As variáveis estudadas foram idade, gênero e diagnóstico. Resultados: Houve a prevalência do gênero masculino (52,6%) e da faixa etária de 30 a 59 anos (43,5%); 21,1% eram idosos. Os diagnósticos mais prevalentes foram conjuntivite infecciosa (23,9%), trauma ocular (15,7%) e doenças da superfície ocular (14,6%). Entre mulheres e crianças houve o predomínio de quadros infecciosos/inflamatórios; 83,6% dos traumas ocorreram em homens, sendo 62,2% devido a corpo estranho. Conclusão: Os diagnósticos mais prevalentes no serviço de urgência oftalmológica foram conjuntivite infecciosa e trauma ocular. Medidas de educação e prevenção são necessárias para reduzir morbidade e absenteísmo e evitar o uso inapropriado dos serviços especializados de emergência.
Abstract Objective: To identify the most frequent diagnosis and epidemiological characteristics of patients attended in a public ophthalmic emergency service. Methods: This is a retrospective and transverse study based on 2834 patients' chart attended from July to September 2017 at the Ouro Verde Hospital Complex, Campinas, Brazil. The following variables were investigated: age, gender, and diagnosis. Results: Most patients were male (52.6%) and aged between 30 to 59 years (43.5%); 21.1% were elderly. The most frequent diagnostics were conjunctivitis (23.9%), ocular trauma (15.7%), and ocular surface disorders (14.6%). Infectious/inflammatory conditions predominated among children and female; 83.6% of traumas occurred in man, and 62.2% were due to a foreign body. Conclusion: The most prevalent diagnoses in the ophthalmologic emergency department were infectious conjunctivitis and ocular trauma. Education and prevention measures are necessary to reduce morbidity and absenteeism and to avoid inappropriate use of specialized emergency services.
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Humanos , Masculino , Feminino , Recém-Nascido , Lactente , Pré-Escolar , Criança , Adolescente , Adulto , Pessoa de Meia-Idade , Traumatismos Oculares/diagnóstico , Prontuários Médicos , Conjuntivite/diagnóstico , Oftalmopatias/prevenção & controle , Oftalmopatias/epidemiologia , Epidemiologia Descritiva , Estudos Transversais , Estudos Retrospectivos , EmergênciasRESUMO
The impact of neurological disorders in society is growing with alarming estimations for an incidence increase in the next decades. These disorders are generally chronic and can affect individuals early during productive life, imposing real limitations on the performance of their social roles. Patients can have their independence, autonomy, freedom, self-image, and self-confidence affected. In spite of their availability, drugs for the treatment of these disorders are commonly associated with side effects, which can vary in frequency and severity. Currently, no effective cure is known. Nowadays, the biopharmaceutical research community widely recognizes arthropod venoms as a rich source of bioactive compounds, providing a plethora of possibilities for the discovery of new neuroactive compounds, opening up novel and attractive opportunities in this field. Several identified molecules with a neuropharmacological profile can act in the central nervous system on different neuronal targets, rendering them useful tools for the study of neurological disorders. In this context, this review aims to describe the current main compounds extracted from arthropod venoms for the treatment of five major existing neurological disorders: stroke, Alzheimers disease, epilepsy, Parkinsons disease, and pathological anxiety.
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Animais , Animais Peçonhentos , Doenças do Sistema Nervoso/terapia , Venenos de Artrópodes/uso terapêuticoRESUMO
The impact of neurological disorders in society is growing with alarming estimations for an incidence increase in the next decades. These disorders are generally chronic and can affect individuals early during productive life, imposing real limitations on the performance of their social roles. Patients can have their independence, autonomy, freedom, self-image, and self-confidence affected. In spite of their availability, drugs for the treatment of these disorders are commonly associated with side effects, which can vary in frequency and severity. Currently, no effective cure is known. Nowadays, the biopharmaceutical research community widely recognizes arthropod venoms as a rich source of bioactive compounds, providing a plethora of possibilities for the discovery of new neuroactive compounds, opening up novel and attractive opportunities in this field. Several identified molecules with a neuropharmacological profile can act in the central nervous system on different neuronal targets, rendering them useful tools for the study of neurological disorders. In this context, this review aims to describe the current main compounds extracted from arthropod venoms for the treatment of five major existing neurological disorders: stroke, Alzheimer's disease, epilepsy, Parkinson's disease, and pathological anxiety.(AU)
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Animais , Venenos de Artrópodes , Produtos Biológicos , Sistema Nervoso Central , Doenças do Sistema NervosoRESUMO
OBJETIVO: Avaliar in vitro, a influência das substâncias químicas utilizadas durante o preparo endodôntico na força de tração do cimento resinoso Rely-X (3M, Sumaré, Brasil) na dentina radicular bovina. MÉTODOS: Utilizou-se 72 dentes bovinos que tiveram suas coroas seccionadas e raízes padronizadas. A seguir, os espécimes foram incluídos em blocos de resina e receberam tratamento químico por 10 minutos com hipoclorito de sódio nas concentrações de 0,5 por cento, 1 por cento, 2,5 por cento, 5,25 por cento ou gel de clorexidina a 2 por cento, além do grupo-controle que recebeu água destilada. Em seguida os espécimes foram imersos em solução de EDTA a 17 por cento por 3 minutos. Dois espécimes de cada grupo foram submetidos à microscopia eletrônica de varredura para avaliação da superfície. Os espécimes para o ensaio de teste de tração receberam condicionamento com ácido fosfórico a 37 por cento por 15 segundos, sistema adesivo Single-Bond (3M, Sumaré, Brasil) e sobre este aplicado o cimento resinoso Rely-X (3M, Sumaré, Brasil). RESULTADOS: Os resultados em Kgf foram: GClorex (2,26); GNaOCl-0,5 por cento (7,92); GNaOCl-1 por cento (9,70); GNaOCl-2,5 por cento (9,05); GNaOCl-5,25 por cento (8,91); GA (0,61). CONCLUSÃO: O hipoclorito de sódio nas concentrações testadas aumentou a força de adesão do cimento resinoso na dentina de forma significativa frente água destilada e gel de clorexidina a 2 por cento. A observação na microscopia eletrônica de varredura mostrou que a estrutura de dentina radicular que fora tratada com hipoclorito de sódio apresentava túbulos dentinários com diâmetros aumentados, menor quantidade de dentina intertubular, além de áreas de depressões, diferentemente dos grupos-controle e gel de clorexidina a 2 por cento.
OBJECTIVE: This study assessed in vitro how the chemicals used in the preparation of root canals affected the force required to remove the resin cement Rely-X (3M, Sumaré, Brazil) from bovine root dentin. METHODS: The crowns of 72 bovine teeth were sectioned and the roots were standardized. The specimens were then placed in resin blocks and treated for 10 minutes with sodium hypochlorite at 0.5 percent, 1 percent, 2.5 percent or 5.25 percent or chlorhexidine gel at 2 percent. The control group was treated with distilled water. Next, the specimens were soaked in 17 percent EDTA for 3 minutes. The surfaces of two specimens from each group were assessed by electron scanning microscopy. The tested specimens were then treated with 37 percent phosphoric acid for 15 minutes, adhesive system Single-Bond (3M, Sumaré, Brazil) and the resin cement Rely-X (3M, Sumaré, Brazil) was applied over it. RESULTS: The results in Kgf were: GChlorhex (2.26); GNaOCl-0.5 percent (7.92); GNaOCl-1 percent (9.70); GNaOCl-2.5 percent (9.05); GNaOCl-5.25 percent (8.91); GA (0.61). CONCLUSION: Sodium hypochlorite in the tested concentrations increased the adhesion of the resin cement to the dentin significantly when compared with water and 2 percent chlorhexidine. Electron scanning microscopy showed that the structure of the root dentin treated with sodium hypochlorite presented widened dentinal tubules, less intertubular dentin and depression areas, all of which were not observed in the roots treated with water and 2 percent chlorhexidine gel.