RESUMO
The quantification and analysis of the tracks forming the autoradiography image of a tissue section is essential for the measurement of particle emitter concentration and distribution (e.g. (10)B) in the sample. Conventional counting techniques cannot be used when track density is high because of track overlapping. A densitometry supported by image analysis method suitable for these cases has been developed. Optical density measurements obtained for boron solutions of known concentrations showed a linear behavior in the range of concentrations under consideration.
RESUMO
A prospective study was undertaken to assess the radiotoxicity of accelerated particles in pulmonary alveolar macrophages (AM). We evaluated the effects of a single dose (10-75 Gy) of an external low-energy (20 MeV) proton beam on cultured AM oxidative metabolism and phagocytic function. Macrophages are the first line of defense against invading pathogens and are known to generate superoxide anion (O2), nitric oxide (NO), and mediators of antimicrobial and antitumoral defense mechanisms. We obtained AM by bronchoalveolar lavage from young (1-2 month old) and aged (9-12 month old) male Wistar rats. Cell viability, phagocytosis, O2 and NO production in control and proton-irradiated cultured AM were evaluated The effect of proton irradiation on cell viability was dose-dependent The higher doses induced a dramatic decrease in viability in the aged population. Phagocytosis increased 1.3-1.4 fold inboth populations irrespective of the dose delivered. Generation of O2 was always higher in the aged population for all the doses assayed and showed no significant variation from the control values. In the young population a clear increase was observed with doses of 25 and 50 Gy. NO production in AM from young animals rose in a dose-dependent manner. Conversely, proton irradiation did not affect NO production in macrophages from aged animals. The results of this study demonstrate that AM isolated from young and aged rats are functionally different and show a distinct behavior when exposed to proton irradiation. These findings suggest that age may condition response and must be taken into account when accelerated particle-radiotherapy protocols are considered as a valid therapeutic option for the treatment of cancer. To the best of our knowledge, this is the first report comparing sham-irradiated and proton-irradiated young and aged AM.
Assuntos
Envelhecimento/fisiologia , Macrófagos Alveolares/efeitos da radiação , Prótons , Animais , Sobrevivência Celular/efeitos da radiação , Células Cultivadas , Óxido Nítrico/metabolismo , Fagocitose/efeitos da radiação , Ratos , Ratos Wistar , Superóxidos/metabolismoRESUMO
Rat tail epidermis was used to analyze the in vivo response of a biological system to heavy particle irradiation. The conical configuration of the rat tail gives rise to a variable energy degradation of the beam thus yielding information on the damage elicited by 2 different L.E.T. regions of the helium beam at different sites on the same sample. Cytochrome oxidase activity and epidermal thickness were used to analyze the metabolic and structural radioinduced response. Quantitative evaluation of radiation damage revealed marked variations within a few micrometers of tissue.
Assuntos
Hélio , Lesões Experimentais por Radiação/patologia , Pele/efeitos da radiação , Partículas alfa , Animais , Relação Dose-Resposta à Radiação , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Transferência de Energia , Lesões Experimentais por Radiação/enzimologia , Ratos , Ratos Endogâmicos , Pele/enzimologia , Pele/patologiaRESUMO
A new method of preserving eggs at room temperature is discussed. The method consists in the "plastification" in situ of the shell, using a liquid synthetic polyvinyl chloride acetate plastic. The plastified eggs and controls were stored under laboratory conditions at 22 degrees C, and the following variables were studied in relation to time: pH of the thick and fluid white, and of the yolk, loss of weight, diameter, yolk index and Haugh units. The results indicated that this new method preserves edible eggs for periods longer than 135 days.