RESUMO
INTRODUCTION: Mild cognitive impairment (MCI) is defined as a state of the ageing brain midway between normal cognition and dementia. Special attention has been paid to the electrophysiological substrate underlying Alzheimer's disease and MCI in order to identify as early as possible which subjects with MCI progress towards Alzheimer, which could be crucial for starting rehabilitation or pharmacological therapies. AIM: To perform a spectral characterisation of the electroencephalogram in subjects with MCI. PATIENTS AND METHODS: An electroencephalogram was carried out on 41 subjects with MCI in order to analyse the spectral measurements; apolipoprotein E genotype was also performed. RESULTS: In all, 94.8% of the sample displayed a significant increase in energy, and in 66.6% of them this was observed in the theta and delta bands, or both. Significant differences were found in the spectral measurements between carriers and non-carriers of the apolipoprotein E epsilon4 allele in the theta and alpha bands; there was also a statistically significant association between the years of schooling and being a carrier of this allele or not. An increase in the theta-alpha bands was observed in the left temporal region in subjects with a below-average number of years of schooling and carriers of the epsilon4 allele. CONCLUSIONS: In subjects with MCI and carriers of the epsilon4 allele, the alpha and theta cortical rhythms can be affected by similar pathological mechanisms and may be expressed earlier in subjects who have a lower level of schooling.
Assuntos
Transtornos Cognitivos/fisiopatologia , Eletroencefalografia , Idoso , Idoso de 80 Anos ou mais , Apolipoproteína E4/genética , Transtornos Cognitivos/genética , Feminino , Humanos , Masculino , Índice de Gravidade de DoençaRESUMO
We report the synthesis of the triphosphate of 5-methyl 4-N-[6-(p-bromobenzamido)hex-1-yl]-2'-O-deoxycytidine 3A. We also analyzed the formation of intramolecular H-bonds of 5-methyl 4-N-[n-[6-(p-bromobenzamido) caproyl amino]alk-1-yl]-2'-deoxycytidine compounds, and confirmed their presence by 1H-NMR studies. In vitro DNA labeling with modified nucleotides is preliminarily evaluated.
Assuntos
DNA/análise , DNA/metabolismo , Desoxicitidina/análogos & derivados , Desoxicitidina/síntese química , Desoxicitidina/metabolismo , Desoxicitidina/química , Escherichia coli , Ligação de Hidrogênio , Immunoblotting , Espectroscopia de Ressonância Magnética , Plasmídeos/metabolismo , Espectrometria de Massas de Bombardeamento Rápido de ÁtomosRESUMO
Entamoeba histolytica genome was analysed by pulsed field gel electrophoresis under conditions to separate linear chromosomes in the 170-1400 kb range. We identified linear DNA molecules of 227, 366, 631, 850, 1112 and 1361 kb (mean sizes obtained by three different methods) and we estimated their reorientation times and migration velocities at various experimental conditions. DNA shift mobility assays, using ethidium bromide, suggested that bands migrating at 227 and 631 kb contain linear and circular DNA, whereas a band at 436 kb has only circular DNA. We obtained a regression equation relating sizes of supercoiled DNA molecules with their migration velocities during a pulse at constant electric field and temperature. We also developed a computer program (EHPATTERNS) that predicts the migration per pulse and the resolution order of circular and linear E. histolytica DNA at different pulse times and constant driving and frictional forces. The simulation showed that linear DNA molecules frequently co-migrate with circular molecules, but circular molecules change when the pulse time varies. This molecular mixture generates broad bands and difficulties in the interpretation of the molecular karyotype of E. histolytica.
Assuntos
DNA Circular/química , DNA de Protozoário/química , DNA Super-Helicoidal/química , Entamoeba histolytica/genética , Animais , DNA Circular/isolamento & purificação , DNA Fúngico/isolamento & purificação , DNA de Protozoário/isolamento & purificação , DNA Super-Helicoidal/isolamento & purificação , Eletroforese em Gel de Ágar/métodos , Etídio , Genoma de Protozoário , Cariotipagem , Análise de Regressão , Saccharomyces cerevisiae/genética , SoftwareRESUMO
The introduction of 6-(p-bromobenzoylamino)caproyl radical in the methyl group of 2'-O-deoxythymidine is described. In vivo incorporation of this nucleoside to DNA was determined using a monoclonal antibody that recognized the radical.
Assuntos
DNA Bacteriano/química , Timidina/análogos & derivados , Escherichia coli/genética , Espectroscopia de Ressonância Magnética , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Espectrofotometria Infravermelho , Timidina/síntese químicaRESUMO
We present here a method to compare the mathematical descriptions of DNA migration per pulse as a function of pulse time. It is based on obtaining robust estimates and variances of DNA reorientation time, migration velocities during and after DNA reorientation; and on the statistical comparisons of these estimates. We demonstrated an equal description for the migration per pulse of each DNA molecule separated under identical conditions in clamped homogeneous electric field (CHEF) and miniCHEF chambers. However, miniCHEF resolved the patterns in shorter times, because it uses thinner samples. The relationship between sample thickness and CHEF run time is also presented.
Assuntos
DNA Fúngico/química , Eletroforese em Gel de Campo Pulsado/métodos , Eletroquímica , Saccharomyces cerevisiae/genética , Fatores de TempoRESUMO
We show here data suggesting that Entamoeba histolytica, the protozoan responsible for human amebiasis, presents DNA amplification in a fashion similar to that described for transformed mammalian cells. By transmission electron microscopy (TEM), we found linear, circular and concentric circular DNA molecules exhibiting the main events of the unscheduled DNA amplification process. Loops were formed after the recombination of two nonadjacent DNA regions, and bubbles appeared from the recombinant strands without involving the looped-out sequences. Bubbles grew up and underwent further replication rounds to produce a nested set of partially replicated circles. Multicircle complexes were also formed from putative replication origin without recombination of distant DNA regions. Clones derived from the strain HM1:IMSS exhibited different DNA contents, suggesting DNA amplification. The parental clone A and its daughter clone C2 differed in rDNA gene copy numbers, but this was observed only when total DNA was separated by pulse field gel electrophoresis, and no significant differences were detected in nuclear DNA. The dissection of the events observed by TEM led us to propose an onion skin model for gene amplification in E. histolytica.
Assuntos
DNA de Protozoário/genética , Entamoeba histolytica/genética , Amplificação de Genes , Animais , Replicação do DNA , DNA Circular/análise , DNA Circular/genética , DNA Circular/ultraestrutura , DNA de Protozoário/análise , DNA de Protozoário/ultraestrutura , Entamoeba histolytica/metabolismo , Microscopia EletrônicaRESUMO
Allele and genotype frequencies for Pvu II restriction fragment length polymorphism of LDL receptor gene were determined in 36 normolipidemic unrelated subjects from Havana City. The frequencies were similar to those reported for other populations.
Assuntos
Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Polimorfismo de Fragmento de Restrição , Receptores de LDL/genética , Adulto , Alelos , Southern Blotting/métodos , Cuba , Enzimas de Restrição do DNA/genética , Marcadores Genéticos , Humanos , Lipídeos/sangue , Pessoa de Meia-Idade , População BrancaRESUMO
El fago Lambda polA (Qam 73, Sam 7) fue aislado y purificado de un lisógeno de la E. coli 594, y posteriormente se multiplicó en una cepa SupE, SupF. Se obtuvo una cantidad considerable de DNA polimerasa I multiplicándolo por vía ciclo lítico, tras la infección a alto MOI (Multiplicity of Infection) de una cepa libre de supresores amber (E. coli WK6). En este trabajo se muestran los resultados de la estandarización de las condiciones para obtener un nivel adecuado de expresión del gen polA, el esquema de purificación utilizado y se discuten las modificaciones realizadas para la obtención de la DNA polimerasa I a gran escala. La DNA pol I purificada incorporó P32-dATP por Nick translation en fragmentos de DNA entre 800-50 000 bp con un alto marcaje específico
Assuntos
Bacteriófago lambda , DNA Polimerase I/isolamento & purificação , Escherichia coliRESUMO
Se desarrolló un prototipo para la electroforesis de campo pulsante en gel de agarosa, que permite separar moléculas de ADN de hasta 2 000 kb. El equipo se fundamenta en la propiedad que tienen las moléculas grandes de ADN, de fraccionarse en geles de agarosa si son sometidas alternadamente a dos campos eléctricos no homogéneos de orientación perpendicular. En los experimentos, los tiempos de pulso fueron 60s, y se estudió la influencia de la fuerza iónica y el tiempo de corrida sobre la resolución de las bandas. El método fue utilizado para obtener el cariotipo electroforético de dos cepas de Saccharomyces cerevisiae. El trabajo describe las distintas partes del equipo, el protocolo electroforético, y la caracterización parcial de algunas bandas mediante hibridización ADN-ADN con sondas específicas para diferentes cromosomas