Low-magnification image analysis of Giemsa stained, electroporation and bleomycin treated endothelial monolayers provides reliable monolayer integrity data.

The aim of this study was to develop an in vitro cell model for studying the in vivo observed vascular effect, induced by exposing blood vessels to changing electric field strengths. Human microvascular endothelial cells (HMEC-1) were cultured as monolayers on 8 chamber glass slides as a model of capillary wall. Exposed to electric pulses alone, or in the presence of bleomycin (electrochemotherapy), monolayers were incubated with culture medium, fixed with methanol, stained with Giemsa, and photographed.

Differential cellular effects of electroporation and electrochemotherapy in monolayers of human microvascular endothelial cells.

In vivo electroporation of tumours shows disruption of blood flow and creates a vascular effect with an initial rapid and transient vasoconstriction phase and a much longer lasting phase with changed microvascular endothelium. These changes are not well understood but are presumed to involve the cytoskeleton. The paper presents for the first time differential in vitro effects describing cytoskeleton changes and monolayer integrity changes by both electroporation and electrochemotherapy of monolayers of human microvascular endothelial cells (HMEC-1).

Pairwise coupling of hair cell transducer channels links auditory sensitivity and dynamic range.

Hair cells in the inner ear provide the basis for the exquisite hearing capabilities of mammals. These cells transduce sound-induced displacements of their mechanosensitive hair bundle into electrical currents within a fraction of a millisecond and with nanometer fidelity. Excitatory displacements of the hair cell's bundle tense tip links that open transducer channels.

Frequency-dependent properties of a fluid jet stimulus: calibration, modeling, and application to cochlear hair cell bundles.

The investigation of small physiological mechano-sensory systems, such as hair cells or their accessory structures in the inner ear or lateral line organ, requires mechanical stimulus equipment that allows spatial manipulation with micrometer precision and stimulation with amplitudes down to the nanometer scale. Here, we describe the calibration of a microfluid jet produced by a device that was designed to excite individual cochlear hair cell bundles or cupulae of the fish superficial lateral line system. The calibration involves a precise definition of the linearity and time- and frequency-dependent characteristics of the fluid jet as produced by a pressurized fluid-filled container combined with a glass pipette having a microscopically sized tip acting as an orifice.

Relationship between olive oil:air, saline:air, and rat brain:air partition coefficients of organic solvents in vitro.

Partition coefficients of 28 volatile organic solvents (13 alkylbenzenes, 10 chlorinated hydrocarbons, and 5 ketones) in olive oil, saline, and rat brain tissue homogenates were measured by equilibration in a closed vial and subsequent gas-chromatographic analysis of headspace air. The values of oil and saline partition coefficients correlate well with previously reported data. Brain partition coefficients were fit to a bilinear equation of the form P(brain:air) = alpha(o)P(oil:air) + alpha(s)P(saline:air) + c.

Selective inhibition of gamma-aminobutyric acid type A receptors in human IMR-32 cells by low concentrations of toluene.

Effects of the neurotoxic organic solvent toluene on human neuronal nicotinic acetylcholine (nACh) and gamma-aminobutyric acid type A (GABA(A)) neurotransmitter receptors were investigated in whole-cell voltage-clamped IMR-32 neuroblastoma cells. Ion currents evoked by near maximum effective concentrations of 1 mM acetylcholine (ACh) and 1 mM gamma-aminobutyric acid (GABA) are inhibited by toluene in a concentration-dependent way. Concentration-effect curves of toluene yield IC(50) values of 276+/-26 and 39+/-6 microM and slope factors of 1.