A total of 83 cholangiograms was performed in three cholecystectomized dogs equipped with Thomas cannulas through which complete and different degrees of incomplete common bile duct obstruction were produced. With incomplete common bile duct obstruction, the iodine concentration in the bile necessary for radiographic visualization of the common duct was always obtained for all three tested iodipamide dosages of .3, .6, and 1.2 ml/kg, infused over 30 minutes. The largest dose resulted in the highest biliary iodine concentrations. With increasing obstruction, an increasing delay of the biliary iodipamide excretion was noted. With complete common bile duct obstruction the iodine concentration in the bile necessary for radiographic visualization of the common duct was never obtained, even with an iodipamide dose increased to 1.8 ml/kg and/or prolongation of the contrast material infusion time from 30 minutes to 2 and 6 hours. Nevertheless, the highest biliary iodine concentration in complete common bile duct obstruction resulted with the largest iodipamide dose (1.8 ml/kg) and the shortest infusion time (30 minutes).

Animals↗

PubMedDate not supplied

Evaluation of various contrast agents for improved arthrography.

In the canine knee joint the monomer methylglucamine iothalamate, the dimer methylglucamine iocarmate, and the nonionic contrast agent metrizamide were examined for use in arthrography. A total of 104 injections were performed with equal iodine concentrations (280-282 mg/ml) and volumes (4 ml) of the three contrast agents. These were evaluated using radiographic comparison and iodine estimations of the joint fluid at various times after injection. Radiographically the dimer was superior, followed by metrizamide and then the monomer. The greatest amount of total iodine within the joint fluid at various times after injection was found with the dimer. Iodine concentrations in the joint fluid were similar for the dimer and metrizamide, both greater than with the monomer.

Animals↗

PubMedDate not supplied

Iothalamate ethyl ester as hepatolienographic agent.

In search of a hepatolienographic agent, the iothalamate ethyl ester particulate suspension was prepared with the average particle size of 1.5 mu in diameter. When mixed with plasma of different animal species, the physical properties of the particular suspension changed significantly. The nature of this difference is not understood but is probably related to protein-particle interaction in the different species. Doses of 550 mg iodine per kg body weight as a single intravenous infusion of the particulate suspension resulted in satisfactory opacification of liver and spleen in rats, followed by complete loss of radiopacity within three days. Larger doses resulted in the death of the rats within 12-14 hours. In general, the mice tolerated larger doses than rats, but there was very poor opacification of the liver, despite good opacification of spleen. Further work is being carried out to improve the suspension and to better understand the difference in behavior of the particulate suspension in different animal species.

Animals↗

PubMedDate not supplied

Renal renin and hemodynamic responses to selective renal artery catheterization and angiography.

Selective renal artery catheterization and renal angiography are commonly performed diagnostic procedures; however, the effects of these procedures on renal blood flow (RBF) and renin release have only been partially described. A biphasic RBF response has been well documented furing selective angiography in dogs. The renal autoregulatory mechanisms governing the responses are uncertain. The renin-angiotensin system and the major parameters of contrast media, hypertonicity and viscosity, have been suggested as important factors. In the canine model, we examined the acute changes in renal venous renin activity along with the renal hemodynamic effects of hypertonicity and viscosity. Our results do not support a primary effect mediated by the renin-angiotensin system. Hypertonicity and the contrast medium per se are significant in active and passive autoregulatory responses at the smooth muscle cellular level.

Angiography↗

PubMedDate not supplied

A comparison of the hemodynamic responses to metrizamide and meglumine/sodium diatrizoate in canine renal angiography.

Selective renal angiography causes a biphasic change in renal blood flow and vascular resistance. In this study, 5 ml of meglumine/sodium diatrizoate (288 mg I/ml, 1455 mosm/kg), metrizamide (290 mg I/ml, 593 mosm/kg), isontonic saline (287 mosm/kg) and hypertonic saline (1500 mosm/kg) were injected into the renal arteries of seven adult mongrel dogs to determine whether the minimum flow (or maximum resistance) was related to the osmolality of the injected agent. The maximum resistance response was significantly smaller for metrizamide (20 +/- 4%) and isotonic saline (19 +/- 2%) than for diatrizoate (36 +/- 6%) or hypertonic saline (50 +/- 7%). Hypertonic saline produced two distinct types of responses: the typical biphasic response or a severe immediate drop in flow. Thus the maximum resistance response was related to agent osmolality. The "injection artifact," or flow changes occurring during the injection, were different for the four agents, and these differences appeared correlated to agent viscosity. Although both contrast media caused relatively small changes in renal hemodynamics, metrizamide caused significantly smaller changes than meglumine/sodium diatrizoate.

Animals↗

PubMedDate not supplied

Reduction in ventricular fibrillation using calcium-enriched Renografin 76.

Renografin 76 has been shown to have significant calcium-binding properties in vivo and in vitro. Two contrast media solutions were compared by selective injection into the right coronary artery of dogs. One set of injections was made with commercially available Renografin 76 (referred to as stock Renografin) and another set of injections was made with Renografin 76 to which had been added 24 mMols/liter of calcium chloride dihydrate. Ventricular fibrillation occurred significantly more often with the stock Renografin 76. The nature of the calcium binding and its effects are discussed.

Angiography↗