The application of nerve growth factor (NGF) to primary adrenal medulla chromaffin cell cultures induces phenotypic changes characterized mainly by the presence of neurites. A similar effect has been seen when these cells are stimulated by extremely low frequency magnetic fields (ELFMF). In this study, newborn rat chromaffin cells were cultured and subjected to NGF or ELFMF in order to compare their histological and ultrastructural characteristics. Cells cultured in the presence of NGF developed cytoplasmic projections and their distal ends showed growth cones as well as filopodia. With scanning and transmission electron microscopy, an increased submembranous electron density was observed in the nuclei of cells as well as irregular, wavy neuritic projections with a moderate number of varicosities, as well as the prevalence of intermediate filaments among the cytoskeleton components. Cells stimulated with ELFMF presented straighter neuritic extensions with a greater number of varicosities. With the transmission electron microscope, numerous neurotubules were observed, both in the cell soma and in their neuritic extensions. In both groups, growth cones were clearly identified by their ultrastructural characteristics. The differences seen in the cytoskeleton of cells stimulated with NGF or ELFMF suggest differential stimulation mechanisms possibly determining the biochemical, electrophysiological, and morphological characteristics in both types of cell cultures.
Background: The mechanism for maintaining telomere integrity is controlled by telomerase, a ribonucleoprotein enzyme that specifically restores telomere sequences, lost during replication by means of an intrinsic RNA component as a template for polymerization. Among the telomerase subunits, hTERT (human telomerase reverse transcriptase) is expressed concomitantly with the activation of telomerase. The role of estrogens and their receptors in the transcriptional regulation of hTERT has been demonstrated. The current study determines the possible association between telomerase activity, the expression of both molecular forms of estrogen receptor (ERα and ERβ) and the protein bcl-2, and their relative associations with clinical parameters.
The application of nerve growth factor (NGF) to primary adrenal medulla chromaffin cell cultures induces phenotypic changes characterized mainly by the presence of neurites. A similar effect has been seen when these cells are stimulated by extremely low frequency magnetic fields (ELFMF). In this study, newborn rat chromaffin cells were cultured and subjected to NGF or ELFMF in order to compare their histological and ultrastructural characteristics. Cells cultured in the presence of NGF developed cytoplasmic projections and their distal ends showed growth cones as well as filopodia. With scanning and transmission electron microscopy, an increased submembranous electron density was observed in the nuclei of cells as well as irregular, wavy neuritic projections with a moderate number of varicosities, as well as the prevalence of intermediate filaments among the cytoskeleton components. Cells stimulated with ELFMF presented straighter neuritic extensions with a greater number of varicosities. With the transmission electron microscope, numerous neurotubules were observed, both in the cell soma and in their neuritic extensions. In both groups, growth cones were clearly identified by their ultrastructural characteristics. The differences seen in the cytoskeleton of cells stimulated with NGF or ELFMF suggest differential stimulation mechanisms possibly determining the biochemical, electrophysiological, and morphological characteristics in both types of cell cultures.
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