Time-dependent reduction of structural complexity of the buccal epithelial cell nuclei after treatment with silver nanoparticles.

Recent studies have suggested that silver nanoparticles (AgNPs) may affect cell DNA structure in in vitro conditions. In this paper, we present the results indicating that AgNPs change nuclear complexity properties in isolated human epithelial buccal cells in a time-dependent manner. Epithelial buccal cells were plated in special tissue culture chamber / slides and were kept at 37°C in an RPMI 1640 cell culture medium supplemented with L-glutamine. The cells were treated with colloidal silver nanoparticles suspended in RPMI 1640 medium at the concentration 15 mg L⁻¹. Digital micrographs of the cell nuclei in a sample of 30 cells were created at five different time steps: before the treatment (controls), immediately after the treatment, as well as 15 , 30 and 60 min after the treatment with AgNPs. For each nuclear structure, values of fractal dimension, lacunarity, circularity, as well as parameters of grey level co-occurrence matrix (GLCM) texture, were determined. The results indicate time-dependent reduction of structural complexity in the cell nuclei after the contact with AgNPs. These findings further suggest that AgNPs, at concentrations present in today's over-the-counter drug products, might have significant effects on the cell genetic material.

New simple ink writing pen system for kymograph recording.

Extraordinarily simple, inexpensive and easily available kymograph ink writing pen system for physiological and pharmacological recordings has been described. The writing part of the pen, consisting of a small porous fibrous writing rod to which a small spongy absorbing cylinder (as an ink container) is added, is attached to one end of a very light plastic strip of which opposite end is connected to a common mechanical lever. The function of the pen was investigated by recording spontaneous frog heart contractions in situ. The pen worked quite well and the recordings were reproducible. The pen can be interesting for researchers working in those physiology and pharmacology laboratories where more sophisticated recorders are not available, and is especially convenient for mass use in students' physiology and pharmacology labs, as alternative for smoked-drum kymograph method.