An improved method for constructing and selectively silanizing double-barreled, neutral liquid-carrier, ion-selective microelectrodes

We describe an improved, efficient and reliable method for the vapour-phase silanization of multi-barreled, ion-selective microelectrodes of which the silanized barrel(s) are to be filled with neutral liquid ion-exchanger (LIX). The technique employs a metal manifold to exclusively and simultaneously deliver dimethyldichlorosilane to only the ion-selective barrels of several multi-barreled microelectrodes. Compared to previously published methods the technique requires fewer procedural steps, less handling of individual microelectrodes, improved reproducibility of silanization of the selected microelectrode barrels and employs standard borosilicate tubing rather than the less-conventional theta-type glass. The electrodes remain stable for up to 3 weeks after the silanization procedure. The efficacy of a double-barreled electrode containing a proton ionophore in the ion-selective barrel is demonstrated in situ in the leaf apoplasm of pea (Pisum) and sunflower (Helianthus). Individual leaves were penetrated to depth of ~150 μm through the abaxial surface. Microelectrode readings remained stable after multiple impalements without the need for a stabilizing PVC matrix

Analýza hlavních vlivů působících na ekonomickou úroveň a činnost odvětví hutnictví železa v podmínkách rozvoje socialistické ekonomické integrace

PrezenčníNeuvedenoNeuveden

Measuring extracellular ion gradients from single channels with ion-selective microelectrodes

Under many different conditions activated plasma membrane ion channels give rise to changes in the extracellular concentration of the permeant ion(s). The magnitude and duration of these changes are dependent on the electrochemical driving force(s) on the permeant ion(s) as well as conductance, open time, and channel density. We have modeled the change in the extracellular [K+] due to efflux through Ca2+-activated K+ channels, mSlo, to determine the range of parameters that would give rise to measurable signals in the surrounding media. Subsequently we have used extracellular, K+-selective microelectrodes to monitor localized changes in [K+]ext due to efflux through mSlo channels expressed in Xenopus oocytes. The rapid changes in [K+] show a close fit with the predicted model when the time response of the ion-selective microelectrode is taken into account, providing proof of the concept. Measurement of the change in extracellular ion concentration with ion-selective microelectrodes provides a noninvasive means for functional mapping of channel location and density, as well as characterizing the properties of ion channels in the plasma membran

Rezul'taty lechenija trikhomonadoza pri pomoshhi preparata Flagyl

Flagyl (8823 R. P.) of Specia production was applied in 62 women with trichomonadosis and in their 54 partners. In women, the treatment was general and local, in men - general. Beneflcial results were obtained in 57 womn, i. e. in 92%. In 5 cases with recurrent disease a secondary contact infection could be demonstrated. Flagyl is advocated for the treatment of trichomonadosis, as it proved to be the most efficient of all hitherto known drugs

Fast response, noninvasive, potentiometric microelectrodes resolve single potassium channel activity in the diffusive boundary layer of a single cell

Ion transport across the plasma membrane of cells involves an inevitable chemical modification of the solutions on both sides. Noninvasive, real-time detection of these subtle ionic signatures is most easily achieved in the extracellular diffusive boundary layer with electrochemical detection. In order to perform these measurements near single cells it is critical to use a device that enables high spatial and temporal resolution. While ion-selective microelectrodes (ISMs) provide the high spatial resolution, they give rise to orders of magnitude increase in the time constant and response time of the microsensors when compared to larger sensors. By constructing and using fast response ISMs biological events as brief as 10ms have been resolved. The signal-to-noise ratio is enhanced with self-referencing and signal processing techniques, enabling long-term monitoring of small magnitude, steady ion gradients and rapid ionic transients that reflect the physiological and metabolic activity of single cell