A cell junction pathology of neural stem cells leads to abnormal neurogenesis and hydrocephalus

Most cells of the developing mammalian brain derive from the ventricular (VZ) and the subventricular (SVZ) zones. The VZ is formed by the multipotent radial glia/neural stem cells (NSCs) while the SVZ harbors the rapidly proliferative neural precursor cells (NPCs). Evidence from human and animal models indicates that the common history of hydrocephalus and brain maldevelopment starts early in embryonic life with disruption of the VZ and SVZ. We propose that a "cell junction pathology" involving adherent and gap junctions is a final common outcome of a wide range of gene mutations resulting in proteins abnormally expressed by the VZ cells undergoing disruption. Disruption of the VZ during fetal development implies the loss of NSCs whereas VZ disruption during the perinatal period implies the loss of ependyma. The process of disruption occurs in specific regions of the ventricular system and at specific stages of brain development. This explains why only certain brain structures have an abnormal development, which in turn results in a specific neurological impairment of the newborn. Disruption of the VZ of the Sylvian aqueduct (SA) leads to aqueductal stenosis and hydrocephalus, while disruption of the VZ of telencephalon impairs neurogenesis. We are currently investigating whether grafting of NSCs/neurospheres from normal rats into the CSF of hydrocephalic mutants helps to diminish/repair the outcomes of VZ disruption.

Prevalência e fatores de risco associados à infecção por Chlamydophila abortus em granjas suinícolas tecnificadas no estado de Alagoas, Brasil / Prevalence and risk factors associated with infection by Chlamydophila abortus in commercial pig farms in the state of Alagoas, Brazil

Objetivou-se com este estudo calcular a prevalência e identificar os fatores de risco associados à infecção por Chlamydophila abortus em suínos criados em granjas tecnificadas no Estado de Alagoas, Brasil. Para compor a amostra do estudo foram utilizados 342 suínos, sendo 312 matrizes e 30 varrões oriundos de sete granjas de ciclo completo e distribuídas em cinco municípios do Estado de Alagoas. O diagnóstico sorológico da infecção por C. abortus foi realizado através da microtécnica de Fixação do Complemento (RFC). A análise dos fatores de risco foi realizada por meio da aplicação de questionários investigativos, constituídos por perguntas objetivas referentes ao criador, às características gerais da propriedade, ao manejo produtivo, reprodutivo e sanitário. Observou-se prevalência de 10,5% (36/342) de suínos soropositivos para a infecção por C. abortus, com 85,8% das granjas analisadas com animais positivos. As variáveis que demonstraram associação significativa foram: utilização de bebedouros comuns para jovens e adultos (p=0,024;OR=10,83; IC=1,36–86,03) e método de cobertura de monta natural associada à inseminação artificial (p=0,05; OR=7,62; IC=1,00-58,31). Relata-se a primeira ocorrência de anticorpos anti-C. abortus em suínos no Brasil. Fatores como a introdução de reprodutores nos plantéis e a forma de fornecimento de água foram evidenciados como facilitadores da infecção das matrizes neste estudo. Dessa forma, medidas de controle da infecção devem ser enfocadas nesse aspecto para evitar a disseminação do agente nas granjas suinícolas e em outros plantéis da região.

The objective of this study was to determine the prevalence and identify risk factors associated with Chlamydophila abortus infection in commercial swine farms on the state of Alagoas, Brazil. To compose the study sample 342 pigs were used, with 312 sows and 30 boars from seven swine farms and distributed in five districts of the Alagoas. The serological diagnosis of infection by C. abortus was performed by fixation of complement microtechnique (RFC). The analysis of risk factors were performed by the application of research questionnaires, consisting of objective questions relating to the designer, the general characteristics of the property, the production, reproductive and health management. I was observed a prevalence of 10.5% (36/342) of pigs seropositive for infection by C. abortus with 85.8% of farms with positive animals analyzed. The variables that showed significant association were use of common drinker for young and adults pigs (p=0.024, OR=10.83, CI=1.36-86.03) and associated the natural mount with artificial insemination (p=0.05, OR=7.62, CI=1.00-58.31). This work reports the first occurrence of anti-C. abortusin pigs in Brazil. Factors as the introduction of boars in herds and the form of water supply were seen as facilitators of infection on sows in this study. Thus measures of infection control should be focused on this aspect to prevent the spread of the agent in pig farms and other herds in the region.

Biodisponibilidad y bioutilización de mezclas de aminoácidos vs. proteínas intactas / Bioavailability and bioutilization of mixtures of amino acids vs. intact proteins

La absorción y utilización del nitrógeno de la dieta fueron estudiadas en ratas en el crecimiento cuando este elemento se suministra en forma de proteina intacta o de mezclas equivalentas de aminoácidos. Las mezclas de aminoácidos ingeridas son absorbidas más eficientemente y ocasionan en el organismo similares valores de deposición proteica, los cuales se logran a expensas de un incrementado consumo de energia y de una redución del compartimiento graso del organismo. La reducción de la ingestión de la dieta y el elevado consumo energético que genera la bioutilización de los aminoácidos aislados no mejora con el suplemento de minerales y oligoelementos. La sustitución de los aminoácidos no esenciales de la dieta por ácido glutámico como única fuente de nitrógeno no esencial, reduce considerablemente la bioutilización del nitrógeno de la dieta