Correlation between radiation dose and p53 protein expression levels in human lymphocytes.

The aim of this research was to evaluate the relationship between p53 protein levels and absorbed doses from in vitro irradiated human lymphocytes. For this, samples of blood from 23 donors were irradiated with 0.5; 1; 2; and 4 Gy from a Cobalt-60 source, and the percentages of lymphocytes expressing p53 were scored using Flow Cytometry. The subjects were divided into 3 groups, in accordance with the p53 levels expressed per radiation dose: low (Group I), high (Group II), and excessive levels (Group III). For all groups, the analyses showed that the p53 expression levels increase with the absorbed dose. Particularly for groups I and II, the correlation between this protein expression and the dose follows the linear-quadratic model, such as for radioinduced chromosomal aberrations. In conclusion, our findings indicate possible applications of this approach in evaluating individual radiosensitivity prior to radiotherapeutical procedures as well as in medical surveillance of occupationally exposed workers. Furthermore, due to the rapidity of flow-cytometric analyses, the methodology here employed would play an important role in emergency responses to a large-scale radiation incident where many people may have been exposed.

60 Hz electric field changes the membrane potential during burst phase in pancreatic ß-cells: in silico analysis.

The production, distribution and use of electricity can generate low frequency electric and magnetic fields (50-60 Hz). Considering that some studies showed adverse effects on pancreatic ß-cells exposed to these fields; the present study aimed to analyze the effects of 60 Hz electric fields on membrane potential during the silent and burst phases in pancreatic ß-cells using a mathematical model. Sinusoidal 60 Hz electric fields with amplitude ranging from 0.5 to 4 mV were applied on pancreatic ß-cells model. The sinusoidal electric field changed burst duration, inter-burst intervals (silent phase) and spike sizes. The parameters above presented dose-dependent response with the voltage amplitude applied. In conclusion, theoretical analyses showed that a 60 Hz electric field with low amplitudes changes the membrane potential in pancreatic ß-cells.