Browsing by Issue Date, starting with "2013-09-22"
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- Expression of adenosine kinase in human mesial temporal lobe epilepsy with hippocampal sclerosis: A preliminary studyPublication . Leal, B.; Rangel, R.; Chaves, J.; Carvalho, C.; Bettencourt, A.; Zenatti, L.; Santos, A.; Magalhães, T.; Martins da Silva, A.; Correia de Sá, P.; Martins da Silva, B.; Costa, P.P.Background: Adenosine is a ubiquitous homeostatic molecule that acts as an “endogenous neuromodulator”. Adenosine attenuates neuronal activity either presynaptically by inhibiting neurotransmitter release or by controlling neurotransmitter responsiveness at post-synaptic sites. Unbalanced adenosine metabolism has been implicated in pathological conditions such as epilepsy. Adenosine kinase (ADK), synthetized by astrocytes, is the key regulator of extracellular adenosine levels in the brain. Evidences from experimental studies support a role for ADK in brain injury associated with astrogliosis, a morphological hallmark of Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis (MTLE-HS). In fact, expression of astrocytic ADK was found to be increased in the hippocampus and temporal cortex of MTLE-HS patients. Overexpression of ADK decreases extracellular adenosine and consequently may cause seizures. The aim of this study was to characterize ADK gene expression in MTLE-HS patients. Methods: Previous studies used immunohistochemistry and Western blot analysis to investigate ADK expression. Here we quantified the expression levels of ADK by Real-Time PCR in the hippocampus (lesional and peri-lesional cortical area) of 10 MTLE-HS patients submitted to surgery as compared with 9 autopsy controls with no history of neurological disorders. Results: Our results showed that ADK expression levels were similar in the hippocampus and temporal cortex of MTLE-HS patients when compared to healthy controls. Conclusion: Our preliminary data demonstrate that ADK expression levels are not altered in MTLE-HS. These results do not preclude post-transcriptional ADK abnormalities at both protein and functional levels. Our results should be confirmed in a larger cohort as well as with complementary methodologies.
- Is serotonin receptor HTR1B implicated in mesial temporal lobe epilepsy development?Publication . Leal, B.; Barreira, A.; Chaves, J.; Carvalho, C.; Bettencourt, A.; Martins da Silva, A.; Costa, P.P.; Martins da Silva, B.Background: Evidences from animal models have demonstrated that depletion of brain serotonin (5-HT), a neurotransmitter with a pivotal role in neurodevelopment and brain plasticity, lowers the threshold to induced seizures. It was also demonstrated that anti-epileptic drugs increase endogenous 5-HT concentrations and that 5HT-1B receptors could have an anticonvulsant role. Association studies have demonstrated that a polymorphism (rs6296) in 5HTR-1B gene may be a susceptibility factor for with temporal lobe epilepsy (TLE) development. The rs6296 G allele has been associated with decreased receptor activity. Our aim was to analyse the association between rs6296 and the development and clinical features of Mesial Temporal Lobe Epilepsy (MTLE) in a Portuguese population. Material and methods: A cohort of 121 MTLE patients (67 F, 54 M, mean age = 44 ± 11 years, age of onset = 13 ± 9 years) was compared with a cohort of 192 healthy individuals (HI). All patients had Hippocampal Sclerosis (MTLE–HS). Genotyping was performed by TaqMan real time PCR methodology. Results: rs6296 G allele was overrepresented in MTLE patients compared to controls (80.2% in MTLE vs 72.1% in HI, p = 0.029 OR = 1.561 (1.060–2.298)). We constituted 2 MTLE–HS sub-groups, according to febrile seizure antecedents and no differences in rs6596 allelic or genotypic frequencies were found. Conclusion: The rs6296 G allele may be a susceptibility factor to MTLE–HS development. Since these receptors have an anticonvulsant role, a reduction in their activity could lower the threshold for seizure development.
- Protein content and amino acid profile in Portuguese ricePublication . Mota, Carla; Cabral, Margarida; Mauro, Raul; Torres, Duarte; Santos, Mariana; André, Catarina; Castanheira, IsabelAccording to INE, between 2010 and 2011, rice (Oryza sativa) availability in Portugal was 15.8 kg per capita per day, which represents the highest in Europe [1]. Rice amino acids profile evaluation is important to define the nutritional quality of different species contributing to choice of the varieties of rice to grow. This study aimed to quantify the total protein and amino acids profile in 15 cultivated accessions selected from the two major subspecies, Japonica and Indica, grown in Portuguese Sado and Ribatejo regions between 2009 and 2011. Total protein was determined by Kjeldahl method and the content of AA was measured by an Ultra Performance Liquid Chromatography of ACQUITY ™ UPLC ® (Waters) system equipped with a photodiode array detector (DAD) with a pre-derivatisation column 6-N-aminoquinolil hidroxisuccinimidil carbamate, after microwave acid hydrolysis. Analysis of the results emphasizes that there was no significant difference between Japonica varieties (6.4 ± 0.5 g/100g) and Indica (7.0 ± 1.6 g/100g) in relation to total protein content. Amino acids score, as defined by WHO/FAO/UNU [2], was between 0.55 (lysine) and 3.24 (aromatic amino acids). Lysine was the only limiting AA (score <1). No significant differences were observed in amino content between subspecies, cultivation region and year of crop. The obtained results may be aggregated and include in the Portuguese Food Composition Databank and EuroFIR Food Platform [3]. Research on wholegrain and husk rice properties is underway and will be discussed.
- Determination of Folates in RicePublication . Delgado, Inês; Chandra-Hioe, Veronica; André, Catarina; Mota, Carla; Arcot, JayashreeA method was developed to determined folic acid (FA), 5-methyltetrahydrofolate (5-MTHF), tetrahydrofolate (THF), 5-Formyltetrahydrofolate (5-CHOTHF) and 10-Formyltetrahydrofolate (10-CHOTHF) using Ultra Performance Liquid Chromatography with a Mass Spectrometer Detector (UPLC-MS). The method was developed according to the literature with different transitions. These transitions were selected for the most intense daughter ion. The parent ion, fragment ion and the conditions are described in table 1. The extraction method included 3-enzimes and SPE to clean the matrix effects. SPE involved several columns but was Oasis form Waters that provided better results. Labeled internal standard were used. 13C-FA was used for FA, 5-CHOTHF and 10-CHOTHF while 13C-5-MTHF was used for 5-MTHF and THF. Analytes were separated thought an Acquity HSS T3 from Waters with water: acetonitrile gradient for 9 minutes and analyzed by negative ion electrospray (ESI-) Multiple Reaction Monitoring (MRM). Three types of rice were tested and values were confirmed with SRM 1849a. This Certified Reference Material has values for FA and 5-MTHF determined by LC/MS/MS.Comparing the results obtained for the reference material analysed with the values present in the certificate we can conclude that the extraction method and chromatographic conditions are suitable for our samples. Brown rice presents the highest content in 5-MTHF and FA. The lowest content of all analysed folate species was found in the rice bran. Brown rice seems to be a better source of folate than whole grain rice, especially for folic acid and 5-methyltetrahydrofolate. However for 10-Formyltetrahydrofolate whole brain rice has a bigger content than brown rice.