RESUMO
Normal anxiety is an adaptive emotional response. However, when anxiety appears to lack adaptive value, it might be defined as pathological. Adaptation in animals can be assessed for example by changes in behavioural responses over time, i.e. habituation. We hypothesize that non-adaptive anxiety might be reflected by impaired habituation. To test our hypothesis, we repeatedly exposed male mice from two inbred strains to a novel environment, the modified hole board. BALB/cJ mice were found to be initially highly anxious, but subsequently habituated to the test environment. In contrast, 129P3/J mice initially showed less anxiety-related behaviour compared with the BALB/cJ mice but no habituation in anxiety-related behaviour was observed. Notably, anxiety-related behaviour even increased during the experimental period. Complementary, 129P3/J mice did not show habituation in other parameters such as locomotor and exploratory activity, whereas significant changes appeared in these behaviours in BALB/c mice. Finally, the expression of the immediate early gene c-fos differed between the two strains in distinct brain areas, known to regulate the integration of emotional and cognitive processes. These results suggest that 129P3/J mice might be a promising (neuro)-behavioural animal model for non-adaptive, i.e. pathological anxiety.
Assuntos
Adaptação Psicológica , Ansiedade , Comportamento Exploratório , Expressão Gênica , Genes Precoces , Habituação Psicofisiológica/genética , Camundongos Endogâmicos , Animais , Ansiedade/psicologia , Transtornos de Ansiedade , Cognição , Cor , Corticosterona/sangue , Modelos Animais de Doenças , Habituação Psicofisiológica/fisiologia , Imuno-Histoquímica , Iluminação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Atividade Motora , Reconhecimento Visual de Modelos , Proteínas Proto-Oncogênicas c-fos/metabolismo , Estresse Psicológico/etiologiaRESUMO
A photodiode in a light-tight housing was used as an x-ray detector. Calibration against a standard ionization chamber showed that, for the range of radiation qualities used in dentistry, its output was a reliable measure of the rate of exposure. Photodiodes are available in very small sizes and can be used intraorally. The feasibility of automatic exposure control for intraoral radiography was considered. Measurement of transmission fractions through the mandible with various radiation qualities resulted in a numerical evaluation of radiation risk approximated by the absorbed dose.
Assuntos
Monitoramento de Radiação/instrumentação , Radiografia Dentária/instrumentação , Desenho de Equipamento , Matemática , Doses de Radiação , Fatores de TempoRESUMO
Recently, advances in a new method of medical imaging have been reported by various authors. The method is based on the physical phenomenon of nuclear magnetic resonance (NMR) and is a well-established technique used in chemistry and physics. Radio waves are transmitted and detected in the presence of magnetic fields; the method is noninvasive and does not use ionizing radiation. The potential use of NMR in dentistry and basic concepts of NMR imaging are discussed.
