Cholic acid accumulation by the ciliary body and by the iris of the primate eye. (1/10)

Cholic acid accumulates in both the ciliary body and the iris of the primate eye during in vitro incubations at 37 degrees C for 1 hr. Incubation at 0 degrees C depresses uptake in both tissues. The washout of preaccumulated cholic acid occurs some 3.4 times faster from the iris than from the ciliary body. The mechanism of cholic acid accumulation in both tissues is less sensitive to inhibition by high iodipamide concentrations and also is less sensitive to inhibition by high hippurate concentrations than the mechanism of p-aminohippurate (PAH) accumulation. Therefore, although overlap may exist, the cholic acid--uptake mechanism differs from the PAH-uptake mechanism in both the primate ciliary body and the primate iris.  (+info)

The choleretic effect of iodipamide. (2/10)

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.  (+info)

Organic cation uptake in vitro by the rabbit iris-ciliary body, renal cortex, and choroid plexus. (3/10)

The uptake in vitro of radioactively labeled test substances was studied in tissues from albino rabbits. Choroid plexus, slices of outer renal cortex, and iris-ciliary body were incubated in a K-rich medium containing one of the cations 14C-Emepronium (Cetiprin), 14C-tetraethylammonium, 14C-choline, or 125I-o-iodobenzyltrimethylammonium and sometimes the anions 131I-o-iodohippurate and 125I-iodipamide. Choroid plexus and renal cortex accumulated all test substances, some to very high tissue-medium ratios. The iris-ciliary body preparation accumulated the anions well but the organic cations only weakly. The only convincing uptake was that of Emepronium. The affinity of this uptake system seemed to be similar to that in the kidney, half-saturating around 10(-4)M Emepronium.  (+info)

Multi-slice three-dimensional spiral CT cholangiography: a new technique for diagnosis of biliary diseases. (4/10)

OBJECTIVE: To validate multi-slice three-dimensional spiral CT cholangiography (3-D CTC) in clinical diagnosis of biliary diseases. METHODS: This study included 146 patients with biliary diseases, involving 73 cases of biliary tumor, 87 cases of radioparent calculus, 12 cases of post cholangio-jejunostomy and one case of congenital choledochocyst. The data of thin-slice volumetric CT scan were sent to the workstation (GE Advantage Windows 3.1). Rational 3-D CTC including maximum intensity projection, minimum intensity projection, surface shaded display, CT virtual endoscopy and ray sumption was performed. The diagnostic accuracy of 3-D CTC was compared with that of conventional CT, ultrasonography and endoscopic retrograde cholangiopancreaticography (ERCP). RESULTS: Different biliary diseases showed distinct imaging manifestations on 3-D CTC. As a new technique for assessing the status of post cholangio-jejunostomy, 3-D CTC was superior to conventional CT, ultrasonography and ERCP in diagnosis of negative biliary calculus, extrahepatic cholangiocarcinoma, cancer embolus of the biliary duct, carcinoma of the pancreas head and periampullar carcinoma. It was also superior to conventional CT, ultrasonography or equal to ERCP in diagnosis of hilar cholangiocarcinoma, but inferior to conventional CT and ultrasonography in diagnosis of gallbladder cancer. CONCLUSION: 3-D CTC as a non-invasive and sensitive technique for the diagnosis of biliary diseases with high diagnostic accuracy will greatly increase the detection rate of biliary diseases.  (+info)

Radiation inactivation of multispecific transport systems for bile acids and xenobiotics in basolateral rat liver plasma membrane vesicles. (5/10)

The functional molecular mass of the cholate, phallotoxin, iodipamide, and ouabain transport proteins in isolated basolateral plasma membrane vesicles was determined by radiation inactivation. Purified basolateral plasma membrane vesicles were irradiated (-90 to -120 degrees C) with high energy electrons from a 10-MeV linear accelerator at doses from 0 to 30 megarads. After each dose, the initial uptake, the equilibrium binding, and the binding of the substrates at 4 degrees C were checked. The size of the transporting function was, for cholate, 107 +/- 8.9 kDa; for phallotoxin, 104 +/- 7 kDa; and for ouabain, 120 +/- 4.7 kDa. The target size for the binding proteins was 56 +/- 4.2, 57 +/- 5, and 47.2 +/- 1.95 kDa for cholate, phallotoxin, and taurocholate, respectively. In the case of iodipamide, the functional molecular mass for both the transport and binding proteins was 54 +/- 4.8 kDa.  (+info)

Two hepatic cytoplasmic protein fractions, Y and Z, and their possible role in the hepatic uptake of bilirubin, sulfobromophthalein, and other anions. (6/10)

Two hepatic cytoplasmic protein fractions, designated Y and Z, which bind sulfobromophthalein (BSP), bilirubin, and other organic anions, have been separated by G75 Sephadex gel filtration. The physiologic role of these protein fractions has been investigated. They are present in the 110,000 g supernatant fraction from the livers of all the species tested (rats, mice, guinea pigs, Rhesus monkeys, sheep, and man). Tissues which do not preferentially extract BSP or bilirubin from plasma do not contain these fractions, with the exception of small intestinal mucosa which contains Z. Anion binding by Y and Z fractions is not due to contamination with albumin. These fractions are responsible for the cytoplasmic localization of bilirubin in Gunn rats, and the fractions bind bilirubin, BSP, or indocyanine green (ICG), whether given in vivo or added in vitro to liver supernate from normal rats. Flavaspidic acid-N-methylglucaminate, bunamiodyl, and iodipamide, drugs known to interfere with the hepatic uptake mechanism, compete with bilirubin and BSP for binding to Z. These proteins appear to be important in the transfer of organic anions from plasma into the liver and provide a tool for the investigation of hepatic uptake mechanisms.  (+info)

Iotroxamide studies in man--plasma binding, renal and biliary excretion studies in jaundiced and anicteric patients. (7/10)

1.A decrease in the plasma binding of iotroxamide was found in jaundiced people. 2. The decrease in binding was associated with an enhancement in renal excretion. 3. Iotroxamide consistently gave higher biliary iodine concentrations than ioglycamide.  (+info)

Vascular exchange in the kidney. Regional characterization by multiple indicator tomography. (8/10)

In previous work with the method of multiple indicator dilution (MID), we have established that a spatially distributed model of transcapillary exchange proposed by Goresky, Ziegler, and Bach (GZB) accurately describes, at the in vivo whole-organ level, the handling of extracellular indicators in the canine renal cortex. To date, however, it has not been possible to assess the key hypothesis that GZB corresponds to the actual local mechanism of exchange in vivo and is not just a compact summary of the kidney's average whole-organ behavior. By adapting the MID method to high speed computed tomography (CT), we are now able to report that the GZB mechanism is an accurate description of renal cortical transcapillary exchange down to volumes of cortical tissue comprising no more than a few per cent of the total cortical mass, i.e., containing no more than a few thousand nephrons. A small bolus of iohexol (radiopaque extracellular indicator) or iodipamide ethyl ester microparticles (radiopaque plasma indicator) injected into the renal artery was followed by CT as it passed through the kidney and into the renal vein. Time-attenuation value curves of the two contrast media obtained from the renal vein and from regions of interest in the cortex were then modeled with the GZB mechanism and with a more complex formulation that includes GZB as a limiting case. When applied to the data, the models converged to GZB as the best fit for each region examined. The GZB mechanism is found to provide excellent agreement with the regional data.  (+info)

• 1
• 2