RESUMO
Alzheimer's disease (AD) is clinically characterized by progressive memory loss, behavioral and learning dysfunction and cognitive deficits, such as alterations in social interactions. The major pathological features of AD are the formation of senile plaques and neurofibrillary tangles together with neuronal and vascular damage. The double transgenic mouse model of AD (2xTg-AD) with the APPswe/PS1dE9 mutations shows characteristics that are similar to those observed in AD patients, including social memory impairment, senile plaque formation and vascular deficits. Mesenchymal stem cells (MSCs), when transplanted into the brain, produce positive effects by reducing amyloid-beta (Aß) deposition in transgenic amyloid precursor protein (APP)/presenilins1 (PS1) mice. Vascular endothelial growth factor (VEGF), exhibits neuroprotective effects against the excitotoxicity implicated in the AD neurodegeneration. The present study investigates the effects of MSCs overexpressing VEGF in hippocampal neovascularization, cognitive dysfunction and senile plaques present in 2xTg-AD transgenic mice. MSC were transfected with vascular endothelial growth factor cloned in uP vector under control of modified CMV promoter (uP-VEGF) vector, by electroporation and expanded at the 14th passage. 2xTg-AD animals at 6, 9 and 12 months old were transplanted with MSC-VEGF or MSC. The animals were tested for behavioral tasks to access locomotion, novelty exploration, learning and memory, and their brains were analyzed by immunohistochemistry (IHC) for vascularization and Aß plaques. MSC-VEGF treatment favored the neovascularization and diminished senile plaques in hippocampal specific layers. Consequently, the treatment was able to provide behavioral benefits and reduce cognitive deficits by recovering the innate interest to novelty and counteracting memory deficits present in these AD transgenic animals. Therefore, this study has important therapeutic implications for the vascular damage in the neurodegeneration promoted by AD.
RESUMO
A deterioração “blown pack” é caracterizada por abundante produção de gás e odor desagradável, induzindo à completa distensão da embalagem durante o processo de estocagem sob refrigeração de cortes cárneos embalados a vácuo. Assim, o objetivo deste trabalho foi o de determinar os possíveis microrganismos envolvidos nessa deterioração através da quantificação e caracterização das populações de Enterobacteriaceae e quantificação de bactérias ácido-lácticas, além da pesquisa de Clostridium estertheticum e Clostridium gasigenes, através da PCR, em carnes próprias para o consumo e em carnes que apresentaram a deterioração “blown pack”. Foram analisadas 54 peças de carne embaladas a vácuo, sendo 27 com deterioração e 27 sem deterioração. As populações médias de enterobactérias foram de 1,7x106 UFC/mL para amostras deterioradas e de 5,5x103 UFC/mL nas não deterioradas, d
RESUMO
"Blown pack" spoilage is characterized by abundant production of gas and off-odor leading to swelling of the packing of vacuum-packed chilled meat cuts. The aim of this study was to determine possible microorganisms involved in this spoilage by quantifying and characterizing the population of Enterobacteriaceae, quantifying lactic-acid bacteria, as well as researching Clostridium estertheticum and Clostridium gasigenes by PCR in meat proper for consumption and meat presenting "blown pack" spoilage. Fifty-four vacuum-packed meat cuts were analyzed, of which 27 were spoiled and 27 non-spoiled. Average enterobacteria population was 1.7x10° CFU/mL and 5.5x103 CFU/mL for spoiled and non-spoiled samples, respectively. Average lactic-acid bacteria population was 5.5x10 and 1.0x10 CFU/mL for spoiled and non-spoiled samples, respectively. The most prevalent enterobacteria species was Hafnia alvei. Meat showing "blown pack" spoilage had higher frequency of positive samples for Clostridium estertheticum. No statistically significant difference was observed in the population of Clostridium gasigenes between "blown pack" spoilage and non-spoiled meat. It was concluded that the most efficient method to control "blown pack" spoilage is to prevent meat contamination by fecal material.
A deterioração "blown pack" é caracterizada por abundante produção de gás e odor desagradável, induzindo à completa distensão da embalagem durante o processo de estocagem sob refrigeração de cortes cárneos embalados a vácuo. Assim, o objetivo deste trabalho foi o de determinar os possíveis microrganismos envolvidos nessa deterioração através da quantificação e caracterização das populações de Enterobacteriaceae e quantificação de bactérias ácido-lácticas, além da pesquisa de Clostridium estertheticum e Clostridium gasigenes, através da PCR, em carnes próprias para o consumo e em carnes que apresentaram a deterioração "blown pack". Foram analisadas 54 peças de carne embaladas a vácuo, sendo 27 com deterioração e 27 sem deterioração. As populações médias de enterobactérias foram de 1,7x10° UFC/mL para amostras deterioradas e de 5,5x10³ UFC/mL nas não deterioradas, de bactérias ácido-lácticas foram, respectivamente, de 5,5x108 e 1,0x10 UFC/mL. Dentre as enterobactérias, a espécie de maior prevalência foi Hafnia alvei. A maior frequência de amostras positivas para o Clostridium estertheticum foram aquelas apresentando a deterioração "blown pack". Não houve diferença estatística significativa para a presença do Clostridium gasigenes entre amostras com deterioração "blown pack" e carnes não deterioradas. Concluiu-se que a principal forma de controle desta deterioração é a prevenção da contaminação da carne por material fecal.