Improvement of the accuracy by the measurement of the electrical cell membrane parameters.

The electrical parameters of the cell membrane are mostly estimated employing ac methods. The measurement is based on the analysis of the current(s) flowing through an access resistance and the membrane. A current/potential transducer is used at the input of the device.

Versatile tool for the manipulation of electrophoresis chips.

This communication describes a versatile tool allowing standard operations (i.e. washing, pre-conditioning, separation, inner surface modification of the chip channel) with capillary electrophoresis chips.

A method of resolution improvement by the measurement of cell membrane capacitance.

When measuring cell membrane electrical capacitance in whole cell configuration using alternating currents, the resolution decreases with increasing membrane conductance and pipette resistance. Improved resolution was attained by the dual-frequency method which was modified as to control the voltage amplitude of one of the measuring frequencies. A model circuit was developed for the verification of the method.

Dual-frequency method for synchronous measurement of cell capacitance, membrane conductance and access resistance on single cells.

A dual-frequency method was developed to monitor changes of membrane capacitance, membrane conductance and serial resistance between patch pipette and cytoplasm of the cell in the whole-cell configuration. Measurement of real and imaginary components of cell admittance during excitation with two superimposed sinusoidal voltage of different frequencies provides mathematical solutions for all three variables. The validity of the method was verified with experiments on mast cells and exocrine pancreatic acinar cells.

Simple device for continuous measurement of fluorescent anions and cations in the rat kidney in situ.

A simple device for fluorescence measurements on kidney surface in situ (FKS) is described. The device consists of (1) an illuminating unit, (2) a detector, (3) an evaluation unit. The device was developed for measurement of tissue content of anionic sulfofluorescein and cationic 4(4-dimethylaminostyryl)-N-methylpyridinium (ASP) during its secretion by proximal renal tubular cells.