Portal and biliary phases of enterohepatic circulation of corrinoids in humans.

The assimilation of labeled cobalamin and the transport of corrinoids in portal blood, peripheral venous blood, and bile were studied in eight cholecystectomized patients, after ingestion of a dose of cyano[57Co]cobalamin (0.5 microCi). The radioactivity appeared in the portal vein after a delay of 1.5-2 hours and in the peripheral vein 1 hour later. In bile, it reached a maximum at 24-72 hours; the excreted cobalamin corresponded to 1.42% +/- 0.92% of the dose ingested. The output of total corrinoids was 1.85 nmol/day. The high-performance liquid chromatography analysis of bile showed the presence of methylcobalamin, 5'-deoxyadenosylcobalamin, hydroxocobalamin, and an unknown corrinoid. This corrinoid bound to R binder but not to the intrinsic factor, and it had the same retention time as cobinamide. The R binder was the single cobalamin-binding protein found in bile. It was completely saturated in some periods of bile secretion. The corrinoids corresponding to such a period were eluted in Sephacryl S 300 gel filtration (Pharmacia Fine Chemicals, Uppsala, Sweden) in two peaks corresponding to saturated R binder and to free cobalamin. The mean level of total corrinoid was significantly higher in the portal vein (593 +/- 238 pmol/L) than in the peripheral vein (376 +/- 114 pmol/L) (P less than 0.01). This "cobalamin analogue" fraction was hypothetical because it was calculated from the difference between total corrinoid concentration and the so called "true cobalamin" concentration. This difference corresponded to the cobalamin analogue fraction. These data show that bile removes not only cobalamin but also cobalamin analogues and that R binder is the single carrier protein involved in their excretion.

High-performance liquid chromatographic separation and dual competitive binding assay of corrinoids in biological material.

Corrinoids were extracted with hot ethanol from human plasma and faeces and separated by high-performance liquid chromatography. The corrinoids (cobalamin and cobalamin analogues) were quantified in the eluted fractions by a dual radioisotope assay using as binders intrinsic factor and haptocorrin to detect cobalamin and total corrinoids, respectively. Recoveries ranged from 37.7 +/- 5.1% for hydroxycobalamin to 75.0 +/- 9.1% for cyanocobalamin. In plasma, the main forms of cobalamin were the coenzymes methylcobalamin and 5'-deoxyadenosylcobalamin (32.1 +/- 13.4 and 28.4 +/- 12.3%, respectively, of total corrinoids). The cobalamin analogue fraction of plasma was eluted with a retention time close to that of cobinamide and of deoxyadenosylcobalamin. In the faeces, most of the corrinoids separated were detected better by the haptocorrin assay than by the intrinsic factor assay. One corrinoid peak was eluted with the same retention time as cobinamide. This peak was detected by haptocorrin assay but not by intrinsic factor assay. It could therefore correspond to cobinamide.

Anaphylaxis to muscle relaxants: cross-sensitivity studied by radioimmunoassays compared to intradermal tests in 34 cases.

Thirty-four patients (31 female and three male patients) with a previous anaphylactoid shock to muscle relaxants were investigated. The seric antimyorelaxant IgE was detected by radioimmunoassay (RIA), and the results were compared to intradermal test (IDR) reactions to dilutions of the commercial drugs. The RIA was carried out with a Sepharose-myorelaxant solid phase and anti-IgE 125I-labeled IgG. The results corresponded to the percentage of labeled anti-IgE bound on the solid phase. The RIA with Sepharose-alcuronium and Sepharose-choline was estimated positive from determination with normal sera (n = 12) when bound IgE was greater than 1.0% and 1.5%, respectively. The RIA and IDR were positive in 43.5% and 75%, respectively, of the cases, with a concordance of 66%. One test at least was positive in 79.4% of the cases. No correlation was found between IgE seric levels and the RIA nor between the cutaneous sensitivity and the RIA. Cross-reactivity with Sepharose-choline and Sepharose-alcuronium was observed in 50%, and it was demonstrated by IDR in only 34.2%. The RIA demonstrated the specificity of IgE to quaternary ammonium compounds as myorelaxant drugs. The positive IDR revealed the bridging of mast cell-bound specific IgE, depending on structural conditions, such as the flexibility of the molecules or the variable specificity of the antibodies, restricted to quaternary ammonium ions or enlarged to a broader part of the incriminated molecules.

Increased serum corrinoids correlates with disease severity and IgA levels in alcoholic cirrhosis.

Relationship between increased serum cobalamin level and liver disease have been recently reported. In this work, levels of total corrinoids, cobalamin (vitamin B12) and cobalamin analogues and levels of IgA were determined by radioisotope dilution assay and nephelometric laser analyses. They all have been measured in superior vena cava, inferior vena cava and hepatic vein of controls and of alcoholic cirrhotic patients grouped according to the Child-Pugh classification. Compared with normal subjects, venous blood content of total corrinoids, of cobalamin and of IgA in alcoholic cirrhotics increased significantly with the severity of the disease (p less than 0.01). In severe, moderate, and mild alcoholic cirrhosis total corrinoids and cobalamin were, respectively, about 5-, 2-, and 1.5-fold higher than in controls, whereas IgA was 3-, 2.5- and 1.5-fold higher, respectively. The serum IgA level was significantly correlated with the level of seric saturated haptocorrin (r = 0.54; p less than 0.01) and with the seric total corrinoids (r = 0.39; p less than 0.01). In the absence of significant hepatic cytolysis, the enhanced level of seric corrinoids in cirrhosis could be partly explained by a competitive inhibition of the liver uptake of haptocorrin by circulating asialoglycoproteins, including IgA.