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Biomedical subjects

J R Amberg

Publications and source records attributed to J R Amberg.

45 records · Page 3Linked to original sources
PubMedDate not supplied

Hepatic excretion of cholecystopaques introduced into the canine jejunum.

The biliary excretion of five oral cholecystopaques was measured following their introduction into the jejunum of bile fistula dogs. The mean maximal iodine concentration in the bile ranged form a low of 2.2 +/- 0.55 mg per ml following a dose of 33 mg of iodine per kg of iopanoic acid to a high of 12.9 +/- 1.4 mg per ml after the same dose of sodium ipodate. Cumulative excretion at the end of three hours was over five times greater with sodium ipodate in comparison to ipoanoic acid. It is felt that the best explanation of this date is the ability of the more water soluble media to pass through the unstirred water layer of the intestine.

Animals↗
PubMedDate not supplied

Effect of iopanoate on the biliary and urinary excretion of iodipamide.

The effect of sodium iopanoate and iopanoic acid on the biliary excretion of iodipamide in dogs was studied. Enteric administration of sodium iopanoate within one hour of iodipamide infusion reduced biliary iodipamide excretion and increased urinary iodipamide output. The biliary and urinary excretion of iodipamide was not influenced by iopanoic acid administered 40 and then again 16 hrs before iodipamide. These results suggest that iodipamide cholangiography can be employed 16-18 hrs after a standard two-day iopanoic acid oral cholecystogram without decreasing the ability to visualize the biliary ductal system or increasing the urinary iodipamide excretion.

Animals↗
PubMedDate not supplied

Factors in the intestinal absorption of oral cholecystopaques.

Interest in the pharmacokinetics of cholecystopaques initially centered on transport from blood to bile. The data obtained in this effort have been valuable and have shown that the maximal iodine concentration achievable in the bile is quite similar for all of the currently available compounds. This concentration is, of course, dose dependent. the transport of contrast material from the bowel to the blood has been shown to be quite variable. Considerable progress was made in understanding this. The tremendous differences in absorption of iopanoic acid depending upon the pH of the administered solution was an initial revelation. The development of the concept that there is a water layer through which the cholecystopaque must pass before reaching the lipid membrane of the intestinal cell has added clarity to understanding the difference in absorption between water-soluble and water-insoluble cholecystopaques. A complete knowledge of what might enhance or inhibit absorption is not known. There is beginning to be an understanding of how intestinal dose relates to plasma levels. This should lead to an optimal dose-timing scheme for each cholecystopaque. The basic assumption is that the highest iodine concentration in the gallbladder leads to the most accurate cholecystography. If this is true, the gallbladder needs to be offered bile at the maximum concentrations during the period preceding filming. To accomplish this, the appropriate plasma level necessary for maximum excretion is needed. Experimental data suggest that our current clinical methods in regard to dose and dose timing need revision to optimize cholecystography. This revision needs to take place with a careful look at toxicity. Accepting the present premise that oral cholecystography can be improved, perhaps without a significant increase in morbidity, a fundamental question to be asked is: is it worth it?

Animals↗
PubMedDate not supplied

Validation of a computer-assisted method for estimating the number and volume of gallstones visualized by cholecystography.

It is likely that in the near future there will be widespread use of medicinal therapy to dissolve gallstones. The efficacy of medicinal therapy can best be determined by attempting to relate the total surface area of a collection of gallstones to the composition of bile in patients undergoing therapy. Surface area, in turn, can be directly related to gallstone size and number. In this study, involving 48 cholecystectomized patients, we have shown that standard cholecystography, together with a computer-assisted method of metrology, can effectively monitor the above parameters. Determinations of the standard deviation of 1) replicate readings (35.8%) and 2) averaged metrology estimates compared with actual stone volumes (42.9%), as well as correlation of actual stone volumes with averaged metrology estimates (r = 0.961), indicated the magnitude of assessed change in stone volume that would be necessary to accept a roentgenographic decrease or increase in stone size with 95% confidence. Even with the increased precision found in the computer-assisted method as described, to attain a 98% certainty of some volume change it was necessary to have metrology volume change of 50% or more. Actual stone counts were without significant error in 87.5% of the determinations.

Chenodeoxycholic Acid↗
PubMedDate not supplied

Radiographic appearance of the nonabsorbed (unconjugated) and conjugated sodium tyropanoate (Bilopaque) in the bowel.

A series of abdominal radiographs were taken in eight normal volunteers after the ingestion of sodium tyropanoate (Bilopaque). These showed nonabsorbed sodium tyropanoate to have a granular appearance, while the conjugated form had a smooth homogeneous appearance. The appearance of conjugated sodium tyropanoate in the bowel has the same diagnostic significance as conjugated iopanoic acid in the presence of a nonvisualized gallbladder. It indicates that the contrast material has passed through the hepatic ductal system and that there has been an opportunity for the gallbladder to opacify.

Adult↗
PubMedDate not supplied

Epiploic appendicitis: CT characteristics.

Acute infarction of an appendix epiploica resulted in an inflammatory process involving the caudal aspect of the transverse colon and the adjacent greater omentum. Computed tomography demonstrated prominent linear soft tissue densities, an increase in CT number of the involved greater omentum, and posterior displacement of the small bowel. In the setting of acute abdominal pain the location and focal nature of the inflammatory process as seen on CT may allow the radiologist to suggest the correct diagnosis.

Colitis↗