Biomedical subjects
Publications and source records attributed to J Ognjanović.
A modified permanganometric method for determination of tannin in tormentile rhizome is proposed. The results compared with values obtained by the regulations of Ph Yug II, Ph Yug III, Ph Yug IV and DAB 9 are reproducible and the method is fast and simple.
For quantitative analysis of perchlorate in capsules and solutions it has been proposed acidometric determination of perchloric acid in eluate after the use of cation exchangers. The comparison was made with colorimetric method of perchlorate determination after ion pairing with methylen blue which is extracted with chlorophorm and shows the maximum absorption at 655 nm. As an alternative method it has been used flame photometry of cations of these salts. The worked-out method with ion exchangers is recommended as a very suitable due to speed and simplicity of work and accurate and reproducible results.
Increasing concentrations of nicardipine were found to inhibit various types of muscular activation (electrical stimulation, acetylcholine, oxytocin, potassium chloride), as well as the spontaneous rhythmic activity of the isolated rat uterus. The degree of the inhibitory effect of nicardipine depends on the type of activation. Nicardipine showed an exceptionally high efficacy in inhibiting contractions induced by electrical stimulation and of spontaneous rhythmic activity. For inhibition of these contractions, even femtomolar concentrations of nicardipine were sufficient. The relaxant effect of nicardipine depends on the concentration of extracellular calcium and the temperature of the medium. Nicardipine shows high selectivity for the uterine smooth muscle because even in very high concentrations it exerts an insignificant relaxation of the other isolated smooth muscles (oesophagus, bladder, colon descendens) as well as of the isolated intercostal muscle of the rat. Our experiments indicate that nicardipine might have a role in the therapy of premature delivery and abortion because of its great selectivity for the uterine smooth muscle. Nicardipine causes a stronger inhibition of the tonic than of the phasic component of contraction induced by potassium chloride and oxytocin. These findings suggest that potassium chloride and oxytocin act through various populations of calcium channels.
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Methods for determination of nimodipine by potentiometric and conductometric titration are described. The obtained results show that small amounts of nimodipine (2 mg, 4 mg) can be quickly and accurately determined by potentiometric method (KV < 2.7%) and that conductometric titration can be applied as an alternative method for quantitative analysis (KV < 1.8%).