A polarographic, oxygen-selective, vibrating-microelectrode system for the spatial and temporal characterisation of transmembrane oxygen fluxes in plants.

A simple procedure is described for the fabrication of micrometer to nanometer-scale platinum electrodes to be used in a vibrating oxygen-selective system. The electrode was prepared by etching a fine platinum wire and insulating it with an electrophoretic paint. The dimensions allowed this electrode to be used with the "vibrating probe technique" in exploratory studies aimed at mapping and measuring the patterns of net influxes as well as effluxes of oxygen in Olea europaea L.

Determination of flubendazole in pharmaceutical dosage forms by differential pulse polarography and UV spectroscopy.

A precise and accurate differential pulse polarographic method was developed for the determination of flubendazole in dosage forms without any prior extraction procedure of interference from the other stated ingredients. A UV spectroscopic procedure was also described and used as reference method. Analyses were generally performed at the 4 micrograms ml-1 flubendazole level.

Determination of isosorbide-5-mononitrate in tablets by differential pulse polarography.

A differential pulse polarographic method requiring little sample separation was developed for the determination of isosorbide-5-mononitrate in tablet dosage form with the standard addition technique and without interference from common excipients. Britton-Welford buffer (pH 3.0) was used as the supporting electrolyte, the single peak occurring at -0.

The iridium/iridium oxide electrode for in vivo measurement of oesophageal and gastric pH.

An iridium-iridium oxide electrode for in vivo pH measurement of the distal oesophagus is described. It is small and flexible so it is well accepted by patients for long-term pH monitoring. The electrode also offers the possibility of including another electrode and/or a pressure sensor for simultaneous detection of two or more parameters--gastric pH or oesophageal pressure for example.

Potentiometric titration of thiols, cationic surfactants and halides using a solid-state silver-silver sulphide electrode.

A rugged, low resistance silver-silver sulphide solid-state electrode for determining pharmaceuticals as authentic samples or in dosage forms by potentiometric titration is described. Sodium tetraphenylborate, mercury(II) acetate and silver nitrate (0.01) M were employed as titrants in the analysis of cationic surfactants (cetylpyridinium chloride, benzethonium chloride, benzalkonium chloride and chlorhexidine salts), antithyroid drugs (methimazole and propylthiouracil) or sodium halides respectively.

An iridium-iridium oxide electrode for in vivo monitoring of blood pH changes.

An iridium-iridium oxide electrode for in vivo monitoring of blood pH changes is described. Because of its small size, sensitivity, flexibility, strength and fast response, this electrode is suitable for acute implantation even in the small vessels of animals such as rats or guinea pigs, allowing continuous pH monitoring anywhere in the central arteries or veins. Excellent noise-free records have been obtained in the in vivo experiments in animals.

Preliminary experience with the pH-triggered pacemaker.

A cardiac pacemaker capable of responding to blood acidosis by change in its stimulation rate allows adjustment to a patient's metabolic needs. The blood pH is sensed by an iridium oxide electrode in the right atrium. During exercise, the venous pH decreases and the paced ventricular rate increases.

[Clinical and biological aspects in patient with pH-triggered implanted pacemaker (author's transl)].

The Authors have selected the variations of blood pH to drive the pacing rate according to the new biological balance created by exercise. The clinical tests performed on the patients who have had a pH-triggered pacemaker implanted one year previously demonstrated that: a) during physical exercise there is an increase of cardiac rate triggered by the pacemaker, comparable with that noted when sinus rhythm is present; b) situations causing an increased production of cathecolamines and thus a pH variation--Cold Pressor Test, Ischaemic Test, as well as emotional stress--cause an increase of the stimulation rate of pH triggered pacemaker.

Use of an iridium electrode for direct measurements of pI of proteins after isoelectric focusing in polyacrylamide gel.

The use of an iridium microelectrode 0.5 mm in diameter is proposed for measuring the pH gradient in polyacrylamide gels after isoelectric focusing. The electrode exhibits a perfectly linear potential/pH relationship; thus it can be used directly in conjunction with a pH meter using the pH scale for readings.

[Effects of citidine diphosphocholine (citicholine) and phospholipids on the elastic properties of the lung and on the physico-chemical properties of the irrigation liquid].

The effect of citidin-diphosphocholine and of phospholipids treatments on the elastic properties as well as on the washing liquid physical-chemical properties of rat lungs is studied. Significant increase of the compliance and decrease of the tendency to collapse of the airways are observed after treatment with citidin-diphosphocholine.