Bovine central nervous system development / Desenvolvimento do sistema nervoso central de bovinos

Central nervous system (CNS) development researches are extremely important to the most common congenital disorders and organogenesis comprehension. However, few studies show the entire developmental process during the critical period. Present research can provide data to new researches related to normal development and abnormalities and changes that occur along the CNS organogenesis, especially nowadays with the need for preliminary studies in animal models, which could be used for experimental research on the influence of viruses, such as the influence of Zika virus on the development of the neural system and its correlation with microcephaly in human newborns. Then, present study describes CNS organogenesis in cattle according to microscopic and macroscopic aspects, identifying structures and correlating to gestational period. Fourteen embryos and nine bovine fetuses at different ages were collected and analyzed. All individuals were measured in order to detect the gestational period. Bovine embryo at 17 days age has its neural tube, cranial neuropore, caudal neuropore and somites developed. After 24 days of development, were observed in cranial part of neural tube five encephalic vesicles denominated: telencephalon, diencephalon, mesencephalon, metencephalon and myelencephalon. In addition, the caudal part of neural tube was identified with the primitive spinal cord. The primordial CNS differentiation occurred from 90 to 110 days. The five encephalic vesicles, primordial spinal cord and the cavities: third ventricule, mesencephalic aqueduct, fourth ventricle and central canal in spinal cord were observed. With 90 days, the main structures were identified: (1) cerebral hemispheres, corpus callosum and fornix, of the telencephalon; (2) interthalamic adhesion, thalamus, hypothalamus and epythalamus (glandula pinealis), of the diencephalon; (3) cerebral peduncles and quadruplets bodies, of the mesencephalon; (4) pons and cerebellum, of the metencephalon; (5) medulla oblongata or bulb, of the myelencephalon; and (6) spinal cord, of the primitive spinal cord. After 110 days of gestation, the five encephalic vesicles and its structures were completely developed. It was noted the presence of the spinal cord with the cervicothoracic and lumbossacral intumescences. In summary, the results describes the formation of the neural tube from the neural plate of the ectoderm, the encephalic vesicles derived from the neural tube and subsequent structural and cavities subdivisions, thus representing the complete embryology of the central nervous system.(AU)

Os estudos que descrevem o desenvolvimento do sistema nervoso central (SNC) são de suma importância para compreensão da organogênese e identificação dos prováveis eventos que resultam em malformações congênitas. Estes dados podem subsidiar novas pesquisas relacionadas ao desenvolvimento normal, e interpretação de malformações e alterações que ocorrem ao longo da organogênese do SNC, considerando neste momento a necessidade de estudos preliminares em modelos animais, os quais poderiam ser utilizados para pesquisas experimentais sobre a influência de agentes infecciosos como o Zika vírus, no desenvolvimento do sistema nervoso e suas relações com a microcefalia em humanos recém-nascidos. O presente estudo teve como objetivo descrever os aspectos morfológicos macro e microscópicos da organogênese do SNC de bovinos, buscando correlacionar os achados morfológicos com a idade gestacional. Todos os animais foram mensurados para detectar o período gestacional. Foram coletados e analisados 14 embriões e nove fetos de bovinos de diferentes idades gestacionais. No embrião bovino a partir do décimo sétimo dia de gestação, encontra-se a formação do tubo neural, o neuroporo cranial e neuroporo caudal, e formação dos somitos. Após 24 dias de desenvolvimento, são observadas na parte cranial do tubo neural cinco vesículas encefálicas denominadas: telencéfalo, diencéfalo, mesencéfalo, metencéfalo e mielencéfalo; e na parte caudal do tubo neural, encontra-se a medula espinhal primitiva. Entre 90 a 110 dias de gestação, observa-se a total diferenciação das cinco vesículas do SNC. Com 90 dias, são identificas as principais estruturas: (1) do telencéfalo, os hemisférios cerebrais, corpo caloso e fórnix; (2) do diencéfalo, a aderência intertalâmica, tálamo, hipotálamo e epitálamo (glândula pineal); (3) do mesencéfalo, os pedúnculos cerebrais e os corpos quadrigêmios; (4) do metencéfalo, a ponte e o cerebelo; (5) do mielencéfalo, a medula oblonga (ou bulbo); e (6) da medula espinhal primitiva, a medula espinhal. Após 110 dias, as cinco vesículas encefálicas e as suas subdivisões se encontram completamente desenvolvidas. Notou-se a presença da medula espinhal com as intumescências cervicotorácica e lombossacral. Em resumo, os resultados demonstram a formação do tubo neural a partir da placa neural do ectoderma, as vesículas encefálicas provenientes do tubo neural e posteriormente as subdivisões das estruturas e das cavidades, que representam a completa embriologia do sistema nervoso central.(AU)

Alteraciones del neurodesarrollo en pacientes con hipotiroidismo congénito: Recomendaciones para el seguimiento / Neurodevelopmental assessment of patients with congenital hypothyroidism

Congenital hypothyroidism (CH) is the most common cause of preventable cognitive disability worldwide. Generally, it is produced by an alteration in the embryogenesis of the thyroid gland or by an alteration in the synthesis of thyroid hormones, which determine that affected patients have low or absent thyroid hormone concentrations. The importance of this fact is that brain development during the first three years of life is highly dependent on thyroid hormones. Prior to the implementation of national neonatal screening programs around the world, 8 to 27% of children with CH had an IQ lower than 70. Nowadays, this percentage is close to 0 in countries that have implemented the program. In Chile, CH neonatal screening program achieved national coverage in 1996. Currently, the incidence of the disease in our country is 1: 3163. The degree of disability produced by CH not only depends on the time of detection of the disease and the prompt start of therapy, but also on an adequate monitoring. Despite screening programs, neurocognitive impairment in schoolchildren and teenagers with CH is still observed, reflected in lower scores in cognitive, language and gross motor assessments, receptive communication, expressive communication, fine motor and gross motor skills compared to healthy children. Also, lesser achievements in learning and language disorders are observed. The objective of this review is to update the information available on neurodevelopment of patients with CH.

Development of the central nervous system in guinea pig (Cavia porcellus, Rodentia, Caviidae) / Desenvolvimento do sistema nervoso central em guinea pig (Cavia porcellus, Rodentia, Caviidae)

This study describes the development of the central nervous system in guinea pigs from 12th day post conception (dpc) until birth. Totally, 41 embryos and fetuses were analyzed macroscopically and by means of light and electron microscopy. The neural tube closure was observed at day 14 and the development of the spinal cord and differentiation of the primitive central nervous system vesicles was on 20th dpc. Histologically, undifferentiated brain tissue was observed as a mass of mesenchymal tissue between 18th and 20th dpc, and at 25th dpc the tissue within the medullary canal had higher density. On day 30 the brain tissue was differentiated on day 30 and the spinal cord filling throughout the spinal canal, period from which it was possible to observe cerebral and cerebellar stratums. At day 45 intumescences were visualized and cerebral hemispheres were divided, with a clear division between white and gray matter in brain and cerebellum. Median sulcus of the dorsal spinal cord and the cauda equina were only evident on day 50. There were no significant structural differences in fetuses of 50 and 60 dpc, and animals at term were all lissencephalic. In conclusion, morphological studies of the nervous system in guinea pig can provide important information for clinical studies in humans, due to its high degree of neurological maturity in relation to its short gestation period, what can provide a good tool for neurological studies.(AU)

Este estudo descreve o desenvolvimento do sistema nervoso central em guinea pig do 12º dia pós-concepção (dpc) até ao nascimento. No total, 41 embriões e fetos foram analisados macroscopicamente e por microscopia de luz e eletrônica. O fechamento do tubo neural foi observado no dia 14 e o desenvolvimento da medula espinhal e diferenciação das vesículas primitivas do sistema nervoso central foram observados no dia 20. Histologicamente, o tecido cerebral indiferenciado foi observado como uma massa de tecido mesenquimal entre os dias 18 e 20 e no 25º dia o tecido no interior do canal medular apresentou maior densidade. No dia 30 o tecido cerebral apresentou-se diferenciado, período no qual a medula espinhal preenchia todo o canal vertebral e foi possível observar os estratos cerebral e cerebelar. No dia 45 as intumescências cervical e lombar foram visualizadas e os hemisférios cerebrais estavam divididos, com uma clara distinção entre substância branca e cinzenta no cérebro e cerebelo. O sulco mediano dorsal da medula espinhal e a cauda equina foram evidentes apenas no dia 50. Não houve diferenças estruturais significativas em fetos de 50 e 60 dpc e animais a termo eram todos lisencefálicos. Estudos morfológicos do sistema nervoso em guinea pig podem fornecer informações importantes para estudos clínicos em seres humanos devido ao alto grau de maturidade neurológica em relação ao seu período de gestação curto, fato que servir como excelente ferramenta em estudos neurológicos.(AU)

Morphological characterization of gecko's (eublepharis macularius) glial cells in culture / Caracterización morfológica de las células gliales del gecko (eublepharis macularius) en cultivo

Central nervous system of reptiles has the ability to grow and regenerate during adult life of the animal. Therefore, cells creating CNS of this animal class should compound substances or molecules enabling neuroregeneration. Cells directly involved in this process have not been clearly characterized, especially in cell culture environment. Morphology of reptilian glial adherent cells should be known better to find any differences from mammalian CNS cells. We isolated glial cells from olfactory bulb and cerebrum from gecko (Eublepharis macularius) and cultured separately. We have observed populations of cells with proliferative capacity in both types of cultures. Also, we have detected lipid molecules deposits within their cytoplasm, which localization was correlated with mitochondria position. This information can be helpful in searching new bioactive substances involved in regeneration of central nervous system.

El sistema nervioso central de los reptiles tiene la capacidad de crecer y regenerarse durante la vida adulta del animal. Por lo tanto, las células de SNC creadas de esta clase de animales deberían componerse de sustancias o moléculas que permiten la neuroregeneración. Las células que participan directamente en este proceso no han sido claramente caracterizadas, especialmente en el entorno de cultivo celular. La morfología de las células adherentes gliales de reptiles deben ser reconocidas y diferenciarse respecto a las células del SNC de mamíferos. Se aislaron células gliales del bulbo olfatorio y el cerebro del Gecko (Eublepharis macularius) y se cultivaron por separado. Se observaron poblaciones de células con capacidad proliferativa en ambos tipos de cultivos. Además, se detectaron moléculas de depósitos lipídicos dentro de su citoplasma, y su localización se correlacionó con la posición de las mitocondrias. Esta información puede ser útil en la búsqueda de nuevas sustancias bioactivas que participan en la regeneración del sistema nervioso central.

Effects of maternal postpartum thyroiditis on thyroid function, intelligence quotient and cognitive development of their offspring

The effect of thyroid hormones on all stages of the development of central nervous system has been documented in different studies. Postpartum thyroiditis [PPT] is associated with high titers of TPO-Ab during pregnancy. Thyroid autoimmunity in pregnancy results in reduction of serum free thyroxin level, even in the presence of normal thyroid function. This study was conducted to evaluate the effect of PPT on the thyroid function and cognitive development of the offspring. Materials and Methods: In this prospective cohort study, conducted between December 2007 and March 2008, children born to mothers who had developed postpartum thyroiditis after delivery and those mothers who had not, were included in this study. Blood and urine samples were obtained from all children and blood samples were drawn from their mothers. All children underwent 7 cognitive tests in a clinical psychology laboratory. Results: We enrolled 124 children for the study, 55 cases [children of mothers with PPT] and 69 controls [children of mothers without PPT]. Average age of cases was 9.5 +/- 1.4 and in controls was 9.4 +/- 0.1 [P=0.2]. No difference was noted between the two groups for baseline characteristics which might have affected their neurodevelopment. Mean scores for total IQ, performance IQ, and verbal IQ in cases and controls were as follows: 115 +/- 10 vs. 116 +/- 12, 113 +/- 11 vs. 116 +/- 12, and 113 +/- 12 vs. 113 +/- 13, respectively [P=0.5]. There was no difference between the results of the other tests [CPT, WCST, PRM Test, SWM Test, MFVP Test, SOC] in the two groups. No difference was noted between the thyroid function of the two groups. Conclusion: Prevalence of goiter, thyroid function, cognitive development, and intelligence quotient of children born to mothers who later develop postpartum thyroiditis are similar to those of normal children. Postpartum thyroiditis in mother is not a threat for the newborn

Lista acotada de adquisiciones motoras del desarrollo durante el primer año / Fenced list of motor assessment of the development during the first year

Se describen la importancia de la detección de trastornos del desarrollo en el primer año de vida y los métodos empleados. Se detalla una versión abreviada de adquisiciones del desarrollo basada en la Lista de Adquisiciones de Habilidades Motoras de Lois Bly, la cual es considerada una herramienta de gran utilidad. Esta lista o inventario refiere los componentes motores específicos, base para el logro de hitos posteriores. Evalúa las habilidades motoras correspondientes según edad, permite monitorear progreso y calidad, y guiar el tratamiento si hay déficits. Determina los Puntos Llave o habilidades motoras claves que abren paso a otras y los Signos Atípicos, patrones motores diferentes que pueden comprometer el futuro desarrollo infantil.

This article explains the importance of an early diagnosis in neurodevelopment during the first year of life and the different methods employed. It describes a short form of the Motor acquisition checklist by Lois Bly, which is considered of great utility. This checklist presents specific motor components, which are the basis to reach the following milestones. It evaluates motor abilities according to age, and allows to monitor progression and quality of movement as well as to guide treatment. Key points of motor abilities that allow the acquisition of other abilities in the future, and the atypical signs, which mean different motor patterns that can alter the children development, are determined.

Effects of low X-radiation doses on the central nervous system development: an experimental study in rats / Efeitos de baixas doses de radiação-X no desenvolvimento do sistema nervoso central: estudo experimental em ratos

OBJETIVO: Este trabalho analisa as conseqüências da irradiação-X no desenvolvimento do sistema nervoso de fetos de ratos. MATERIAIS E MÉTODOS: O trabalho foi constituído de 10 Rattus norvegicus albinos, Wistar, fêmeas, grávidas, com idade de oito semanas. Cinco ratas fêmeas constituíram o grupo controle e outras cinco tiveram suas regiões abdominais expostas por 30 segundos a uma dose de 0,3 Gy proveniente de um aparelho odontológico Gnatus de 70 kV e 10 mA. No 17º dia gestacional, ambos os grupos foram submetidos a histerectomia. As seções selecionadas foram examinadas para análise cerebral comparativa entre os grupos. RESULTADOS: O exame clínico revelou não haver diferenças morfológicas entre os grupos controle e experimental e nenhum dos animais apresentou anormalidades grosseiras. Vinte e sete por cento dos animais do grupo experimental apresentaram hemorragia cerebral moderada e 73 por cento apresentaram hemorragia severa e danos no tecido nervoso. Nenhum animal do grupo controle apresentou hemorragia cerebral ou danificações de tecido nervoso. CONCLUSÃO: Estas evidências demonstram que pequenas doses de radiação-X podem causar hemorragias cerebrais e, conseqüentemente, lesão tecidual nervosa.

OBJECTIVE: The present study analyzes the consequences of X-irradiation for the development of the nervous system of rat fetuses. MATERIALS AND METHODS: The sample included ten eight-week-old, pregnant Rattus norvegicus albinus, Wistar. Five female rats constituted the control group and other five had their abdominal region exposed for 30 seconds to a single 0.3 Gy radiation dose from a 70 kV, 10 mA Gnatus odontological apparatus. At the 17th gestational day both groups were submitted to hysterectomy. Selected sections were examined for comparative brain analysis of both groups. RESULTS: The clinical evaluation demonstrated no morphological difference between the control and the experimental groups. Twenty-seven percent of the animals in the experimental group presented mild brain hemorrhage, while 73 percent of the animals had severe cerebral cortex hemorrhage and nervous tissue damage. None of the animals in the control group presented cerebral hemorrhage or nervous tissue damage. CONCLUSION: These evidences demonstrate that low X-radiation doses may cause brain hemorrhage and, consequently, nervous tissue damage.

Entry, dispersion and differentiation of microglia in the developing central nervous system

Microglial cells within the developing central nervous system (CNS) originate from mesodermic precursors of hematopoietic lineage that enter the nervous parenchyma from the meninges, ventricular space and/or blood stream. Once in the nervous parenchyma, microglial cells increase in number and disperse throughtout the CNS; these cells finally differentiate to become fully ramified microglial cells. In this article we review present knowledge on these phases of microglial development and the factors that probably influence them.

Impacto del enriquecimiento ambiental sobre el desarrollo cerebral: interacciones sociales, nutricionales y sensoriales / Impact of the enviromental enrichment upon the cerebral development: social, nutritional and sensorial interaction

The influence of environmental enrichment during the course of early postantal development has been extensively studied. Relatively short periods of simulation, during lactation may be associated with important benefits in functional and behavioral capacities. Furthermore many authors support the idea that evolution is an adaptative response of living material to the enriched conditions present in the habitat. Recently, environmental stimulation has been reported to aid recovery from behavioral deficits associated with early post-natal malnutrition and offer similar prospects for brain lesions, some birth defects and related malformations. It has become evident in recent years that the developing cerebral cortex is sculptured by a highly sophysticated program of neuronal reorganization, influenced by social, cultural and environmental cues. These observations raise a number of questions to both, basic scientists and neurologists, as: What types of changes occur in the brain?. What is the time course of these events?. Perhaps most important, what are the functional implications of cortical reorganizations?. The porpuse of this review is to summarize the evidence, already available in an effort to improve the chances of recovering brain health after perinatal malnutrition, social deprivation or sensorial impairement. According to our results, sensorial enrichment account for a significant acceleration in the dendrogenesis of basal dentritic field in pups that were simultaneously malnourished; nutritional-environmental interactions. The mechanisms through which environment induce modifications in morphology and behaviour have not been elucidated. The most obvious prediction is that environmental influences are probably transduced as chemical expressions in the internal milieu

El desarrollo de la marcha en el niño / Gait developmenting children

El desarrollo de la marcha en el niño es un proceso que implica aprendizaje, además de la maduración del sistema nervioso y del sistema musculoesquelético. Como ayuda para su evaluación, este artículo presenta los principales cambios en la marcha del niño sano entre el primer y el quinto año de vida

Peso bajo al nacimiento y funcionamiento del sistema nervioso central en los primeiros años de la vida / A 3-year follow-up central nervous system function in children with low birth weight

El funcionamiento del sistema nervioso central, medido por la técnica de Gesell durante los tres primeros años de vida de una cohorte de niños rurales, no acusó diferencias en relación al peso denacimiento, edad gestacional, combinación de peso y edad gestacional ni clase socioecónomica. La discrepancia entre estos reultados y los encontrados por otros autores, puede deberse a que la forma de evaluación del desarrollo haya servido como estimulación sistemática, cancelando las diferencias entre niños con y sin riesgo. Por otra parte, las madres de estos niños no necesitaron maniobras invasivas durante el parto y los niños no presentaron daño neurológico al nacimiento, ni alteraciones perinatales, ni signos de hipoxia. El análisis del desarrollo de estos mismos niños a edades posteriores a los tres años de vida, cuando existe mayor sensibilidad en los indicadores de disfunción, será motivo de comunicación posterior

Efecto de la nutrición y ambiente sobre el metabolismo noradrenérgico en el sistema nervioso central: I. Desnutrición animal / Effect of nutrition and environment on nordrenergic metabolism in the central nervous system: I. animal malnutrition

Se presentan los resultados preliminares de la concentración de noradrenalina (NA) y actividad enzimática de dihidroxi-L-fenil-alanina descarboxilasa (DOPAD 4.1. 1.26) en cuatro regiones encefálicas (corteza, hemisferios sin corteza, tallo y cerebelo) en 32 ratas de la cepa Wistar, distribuidas aleatoriamente en un diseño factorial 2 x 3, con dos niveles de nutrición (bien nutridas y desnutridas) y tres condiciones ambientales (estimulación, control y aislamiento). A los 50 días de vida postnatal fueron sacrificadas, se extrajo el encéfalo y se midieron las concentraciones de NA y actividad de la enzima DOPAD. En la concentración de NA por gramo de tejido seco de las cuatro regiones encefálicas estudiadas, se observaron diferencias estadísticamente significativas entre ratas estimuladas y aisladas. Las ratas estimuladas presentaron altas concentraciones de NA. La actividad de la enzima DOPAD por gramo de tejido seco y por hora se mostró baja en los animales que se mantuvieron con sobreestimulación, difiriendo significativamente de las ratas aisladas. Las pendientes de regresión entre la concentración de NA y actividad de DOPAD, fueron contrastadas mediante análisis de covarianza y se obtuvo que los índices de regresión en ratas estimuladas son mayores que los observadores en los subgrupos aislados. No hubo diferencia en el factor nutricional