Changes in the microcirculation of the intact rat heart after iodinated and gadolinium-containing contrast media.

RATIONALE AND OBJECTIVES: A new model was developed to study microcirculation in the intact heart of the anesthetized rat, and the effects of roentgenography and magnetic resonance imaging contrast media were investigated. METHODS: Roentgenography contrast media (600 mg iodine/kg), gadopentetate (0.25 mmol/kg), or physiological saline were injected intraarterially into anesthetized rats (N = 10) whose chests had been opened in a pressurized container. The effects on arterial and venous vasomotion and microhemodynamics of the capillary network were determined in vivo by combined incidental light-fluoroscopic microscopy using continuous 35-mm cine film and video recordings from 5 minutes before until 20 minutes after injection. The amplitude and frequency spectra were evaluated according to the Prony method and by Fourier analysis. Additionally, the number of perfused vessel bifurcations were counted. RESULTS: Gadopentetate exhibited no effects on microcirculation, and diatrizoate exhibited the largest ones. The deformation of the vasomotion spectrum reached 28%, and bifurcations were reduced by 21%. The effects were reversible within 10 minutes of injection. Iotrolan showed minimal disturbance. The other contrast media (iopromide, iopamidol, ioxaglate) fell between these two extremes. CONCLUSION: High-osmolar ionic roentgenography contrast media resulted in a transient deregulation of vasomotion and in a disturbed microcirculation in the rat heart. Isotonic or low-osmolar nonionic roentgenography contrast media or gadopentetate did not show this effect or showed it only to a minimal extent.

Elimination of the diatrizoate-induced effects on the microcirculation by the prostacyclin derivative, iloprost.

RATIONALE AND OBJECTIVES: Contrast media, especially high-osmolar ionic compounds elicit drastic effects on the microcirculation. In some areas of the microcirculatory network, blood flow decreases up to total stasis; in other areas, blood velocity increases. The authors studied the effect of the stable prostacyclin derivative, iloprost, added to the diatrizoate formulation on the number of perfused microvessels in the rat intestine. METHODS: Diatrizoate (600 mg iodine/kg) and increasing concentrations of iloprost, ranging from a total dose of 0 to 560 ng/kg, were injected intravenously into groups of four anesthetized male rats. The number of unperfused microvessels in the intestine were determined by in vivo microscopy. Each animal received two treatments at an interval of 35 minutes. One treatment consisted of diatrizoate alone, the other treatment consisted of diatrizoate plus iloprost. Two animals of each group received first diatrizoate alone and then diatrizoate plus iloprost. The other two animals first received diatrizoate plus iloprost and then diatrizoate alone. RESULTS: Diatrizoate alone reduced the number of perfused microvessels by 45%. The addition of iloprost resulted in a dose-dependent improvement of microcirculation. At a dose of 280 ng/kg, the effects of diatrizoate were completely abolished. Increasing the dose further diminished this effect. CONCLUSIONS: The addition of iloprost to diatrizoate eliminates the deleterious effects of diatrizoate on microcirculation.

[Experimental studies of the vascular reactions in selected microcirculatory areas as affected by various x-ray contrast media]. / Experimentelle Untersuchungen von Gefässreaktionen in ausgewählten mikrozirkulatorischen Regionen unter dem Einfluss verschiedener Röntgenkontrastmittel.

After application of various ionic and non-ionic contrast media in the myocardium and intestine of rats, significant changes of flow conditions in the terminal vascular bed were observed with intravital microscopy: Amidotrizoate causes severe disorder in microcirculation distribution (heterogeneous perfusion, functional shunts), while Ioxaglate, Iopromide, Iohexol, Iotrolan cause significantly less microcirculation reactions.

[Animal experimental studies on the microcirculation of ionic and nonionic x-ray contrast media]. / Tierexperimentelle Untersuchungen zur Mikrozirkulation ionischer und nichtionischer Röntgenkontrastmittel.

In vivo microscopic (video) investigations on the variability of flow conditions in the myocardium and intestines of anaesthesized normal tension rats after application of various ionic and non-ionic contrast media (Amidotrizoate, Ioxaglate, Iopromide, Iohexol, Iotrolan). Amidotrizoate causes heterogeneous microperfusion and functional shunt vessels (distribution disorder) with the typical symptoms of disturbed microcirculation. Ioxaglate, Iopromide, Iohexol and Iotrolan influence microcirculation differently but always to a far less degree.

[Formate incubation of red blood cells from glucose-6-phosphate-dehydrogenase-deficient patients]. / Formiatinkubation roter Blutzellen von Glukose-6-Phosphat-dehydrogenase-Defektträgern.

Attempts of incubating red blood cells of G6PD-defect carriers in 10 from 25 patients showed format in these blood samples is able under the elected conditions to suppress haemolysis, to reduce the numbers of Heinz's bodies and to enhance GSH-concentration. A more distinct efficiency could be observed in enzyme variants with instable temperatures and if kinetic properties had changed. Prevention of haemolysis is particularly suitable as a parameter because it will reflect all damages connected with an enhanced membrane permeability. The increase of GSH-concentration as an important equivalent of reduction in the metabolism of red blood cells may diminish the toxicity of damaging factors having an effect on oxidation. The number of Heinz's bodies is essential in those cases where oxidation products of haemoglobin are increasingly formed only under certain conditions of incubation. The findings allow a format therapy to be recommended for selected G6PD defects.