Biomedical subjects

R N Berk

Publications and source records attributed to R N Berk.

At least 73 records · Page 4Linked to original sources

PubMed1975

An angiographic study of the pre- and postoperative hemodynamics in patients with side-to-side portacaval shunts.

Hepatic panangiography was performed in 17 patients before and after side-to-side portacaval shunts. Preoperatively, a direct correlation existed between the diameters of the hepatic arteries and the severity of the patient's cirrhosis. Postoperatively, the splenic artery and vein and the hepatic artery dilated further in most patients, reflecting increased blood flow. The greatest increase occured in those patients with less severe cirrhosis. The liver shrank postoperatively in most patients. The corrected sinusoidal pressure dropped significantly in all patients. A unique pattern of sinusoidal filling at wedged hepatic venography was observed postoperatively in many of the patients.

Angiography↗

PubMed1975

The choleretic effect of iodipamide.

It is well established that a number of organic anions are excreted by the liver into bile in association with a marked increase in bile flow. Previous studies have shown that iodipamide (3,3'-(adipoyl-diimino)bis[2,4,6-triiodobenzoic acid]), the radiographic contrast material used for intravenous cholangiography, is a potent choleretic. Experiments were performed in unanesthetized dogs to determine if the increased bile flow produced by iodipamide is canalicular or ductular in origin, to quantitate the choleresis associated with iodipamide and taurocholate excretion, and to correlate these findings with the results of in vitro studies in which the osmotic activities of iodipamide and taurocholate in both isotonic saline and bile were determined. The plasma erythritol clearance increase linearly with the excretion of iodipamide, indicating that iodipamide stimulates canalicular bile flow. The choleretic potency of iodipamide (22 ml/mmol) is approximately 3 times that of taurocholate (7.8 ml/mmol), yet the osmotic activity of iodipamide in bile (1.5 mosmol/mmol) is only twice as great as that of taurocholate in bile (0.8 mosmol/mmol). It therefore appears that, per unit of effective osmotic solute secreted, iodipamide carries more water into the bile canaliculi than does taurocholate.

Animals↗

PubMed1975

Biliary excretion of iodipamide.

Conflicting data have been reported concerning the optimum dose and rate of administration of iodipamide required to obtain maximum radiographic opacification of the biliary tree during intravenous cholangiography. Experiments were performed in dogs to determine the effect of plasma concentration on the excretion and concentration of iodipamide in the bile and urine during a steady state of infusion and excretion. The data indicate that a hyperbolic relation exists between the plasma concentration and both the biliary concentration and the total biliary excretion. A mathematical expression of these relations is presented. At low plasma concentrations, iodipamide was not excreted in the urine. However, at high plasma concentrations, urinary excretion increased sharply. It appears that a biliary concentration of iodipamide sufficient to achieve adequate radiographic visualization of the biliary tree can be obtained without significant renal excretion by constant infusion of iodipamide at an appropriate rate in dogs. Stepwise increase in the infusion rate until adequate radiographic visualization is obtained may be the best method for performing intravenous cholangiography to obtain visualization with the least amount of iodipamide in order to minimize toxicity.

Animals↗

PubMed1974