Osmotic properties of some contrast media

Volume changes in the rat renal cortex during urography

At different periods of urography rat kidney were instantly frozen at -165 degrees C. Using appropriate histological techniques and planimetry of different cortical compartments and fractions the structural background of renal cortical volume variations during urography was elucidated. The renal cortex reacted to intravenous injection of hypertonic contrast medium with an immediate increase of volume, followed by a decrease from 30 to 60 seconds. Measuring the volume shares of different cortical compartments, the complex nature of cortical volume variations during the first minutes of urography could be demonstrated. Subdivision of the tubular compartments into cellular and luminal fractions showed even greater complexity of volume variations. All the major cortical volume changes came to an end approximately three minutes after the injections.

Dacryocystography with amipaque (metrizamide)

Amipaque is found to be very suitable for dacryocystography because it has a low osmolality and high viscosity, and is in addition the only aqueous contrast medium currently available which in higher concentrations does not cause pain when applied to the conjunctival sac.

Vectorcardiographic changes at selective coronary angiography. Comparison of two contrast media

Vectorcardiography revealed typical changes following routine selective coronary angiography using Urografin 60% and Isopaque Coronar; the response was dose-dependent. The two contrast media compare well with one another, no statistical difference being recorded, indicating that there is no difference in myocardial toxicity.

Coronary angiography with diatrizoate and metrizamide. Comparison of ionic and non-ionic contrast medium effect on coronary blood flow in dogs

The non-ionic contrast medium metrizamide produced a smaller coronary flow increase than the ionic medium diatrizoate after injection into the main left coronary artery in dogs and had also a shorter transit time through the coronary vessels. The coronary veins were better filled with metrizamide. The reduced coronary flow effects of metrizamide compared to ionic contrast medium and the improved venous filling makes metrizamide a favorable contrast material for use in coronary angiography.

Contrast media: quantitative criteria for designing compounds with low toxicity

Toxicity of contrast media that are ionized iodobenzoic acids or their derivatives is highly correlated with lipid solubility, as measured by the octanol/water partition coefficient. New contrast media have been designed with lower lipid solubility than media in current use, taking into account the additive-constitutive nature of the partition coefficient of an organic compound. If these contrast media are chemically stable, they should also be less toxic. It remains to be tested whether the relation between clinical toxicity and lipid solubility applies to non-ionized contrast media as well.

Chronic effects of osmotic opening of the blood-brain barrier in the monkey

In the monkey, the blood-brain barrier and the blood-aqueous and blood-vitreous barriers of the eye can be opened by internal carotid perfusion of solutions of 2 molar urea in a way compatible with survival and, in some few cases, without detectable neurological deficits. Urea presumably acts by osmotically shrinking the endothelial cells of the cerebrovascular vessels and opening their tight junctions. The high incidence of brain necrosis with neurological sequelae after perfusion of urea by the present technique precludes the use of osmotic opening of the blood-brain barrier for pharmacotherapy at this time.