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1.
Bioelectromagnetics ; 27(7): 521-7, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16715527

RESUMO

We present simple parametric equations in terms of Jacobi elliptic functions that provide a realistic model of abnormal variations in size which maintain the biconcave shape of a normal erythrocyte (anisocytosis) and abnormal variations in shape which maintain the original volume of the erythrocyte (poikilocytosis), as well as continuous deformations from the normal to the altered shapes. We illustrate our results with parameterizations of microcytes, macrocytes, and stomatocytes, and we apply these parameterizations to the numerical calculation of the induced transmembrane voltage in microcytes, macrocytes, and stomatocytes exposed to an external electromagnetic field of 1800 MHz.


Assuntos
Eritrócitos/citologia , Potenciais da Membrana , Fenômenos Eletromagnéticos , Membrana Eritrocítica/efeitos da radiação , Eritrócitos/patologia , Eritrócitos/fisiologia , Humanos , Potenciais da Membrana/efeitos da radiação , Modelos Biológicos , Ondas de Rádio
2.
Bioelectrochemistry ; 64(1): 39-45, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15219245

RESUMO

This paper studies the internal electric field distribution in human erythrocytes exposed to MW radiation. For this purpose, an erythrocyte cell model is exposed to linearly polarized electromagnetic (EM) plane waves of frequency 900 MHz and the electric field within the cell is calculated by using a finite element (FE) technique with adaptive meshing. The results obtained show the dependence of the induced electric field distribution on the main modelling parameters, i.e., the electrical properties (permittivity and conductivity) of the membrane and cytoplasm and the orientation of the cell with respect to the applied field. It is found that for certain orientations, the field amplification within the membrane of the erythrocyte shape cell can be higher than the one observed in an equivalent simple spheroidal geometry cell, commonly used in bioelectromagnetism. The present work shows that a better insight of the interaction of electromagnetic fields with basic biological structures is obtained when the most possible realistic cell shape is used.


Assuntos
Membrana Celular/efeitos da radiação , Forma Celular/efeitos da radiação , Citoplasma/efeitos da radiação , Eritrócitos/efeitos da radiação , Micro-Ondas , Membrana Celular/metabolismo , Citoplasma/metabolismo , Campos Eletromagnéticos , Eritrócitos/citologia , Humanos , Modelos Biológicos , Radiação , Radiometria
3.
Phys Med Biol ; 48(11): 1649-59, 2003 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-12817943

RESUMO

This paper shows the importance of using realistic cell shapes with the proper geometry and orientation to study the mechanisms of direct cellular effects from radiofrequency (RF) exposure. For this purpose, the electric field distribution within erythrocyte, rod and ellipsoidal cell models is calculated by using a finite element technique with adaptive meshing. The three cell models are exposed to linearly polarized electromagnetic plane waves of frequencies 900 and 2450 MHz. The results show that the amplification of the electric field within the membrane of the erythrocyte shape cell is more significant than that observed in other cell geometries. The results obtained show the dependence of the induced electric field distribution on frequency, electrical properties of membrane and cytoplasm and the orientation of the cell with respect to the applied field. The analysis of the transition of an erythrocyte shape to an ellipsoidal one shows that a uniformly shelled ellipsoid model is a rough approximation if a precise simulation of bioeffects in cells is desired.


Assuntos
Campos Eletromagnéticos , Eritrócitos/citologia , Eritrócitos/fisiologia , Micro-Ondas , Modelos Biológicos , Radiometria/métodos , Animais , Polaridade Celular/fisiologia , Tamanho Celular/fisiologia , Simulação por Computador , Citoplasma/fisiologia , Impedância Elétrica , Membrana Eritrocítica/fisiologia , Membrana Eritrocítica/ultraestrutura , Análise de Elementos Finitos , Humanos , Doses de Radiação , Células Fotorreceptoras Retinianas Bastonetes/citologia , Células Fotorreceptoras Retinianas Bastonetes/fisiologia
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