Specific interaction between antidigoxin antibodies and digoxin-like immunoreactive substances in cord serum

Digoxin-like immunoreactive substances (DLIS) have been quantified by two different digoxin radioimmunoassays (RIA) in 47 cord sera. The mean DLIS value (in digoxin equivalents) ranged from 0.960 (SD 0.184) to 0.181 (SD 0.104) nmol/L between the two different kits and different lot numbers of the reagents. One of the RIA methods showed an obvious lot-to-lot effect. The use of a longer incubation interval and a higher incubation temperature markedly decreased cross reactions with DLIS. The effect of modifying the incubation conditions in RIA is similar to that described for assays of steroids because the dissociation rates of the immunocomplex play a critical role. Data suggest a specific interaction between DLIS and digoxin antibodies. Control of the incubation conditions is recommended, to decrease or increase the amount of the DLIS in cord serum specimens.

Combined liquid-solid chromatography and radioimmunoassay for determination of morphine in human fluids

A liquid-solid chromatography radioimmunoassay (LSC-RIA) method for the quantitation of morphine in plasma is described. The detection limit is 1 ng/ml of morphine per milliliter of plasma. Morphine is initially isolated from its inactive hydrosoluble metabolites by LSC, and is then quantified by RIA. Recovery and reproducibilities inter- and intraassay are satisfactory. The procedure uses commercially available granular matrix (Extrelut) and a RIA 125I morphine kit (Abuscreen) and does not require sophisticated analytical techniques. It can be carried out in any pharmacological laboratory. The procedure has been successfully applied to the investigation of morphine kinetics in nine treated patients, via three different administration routes.

A comparative study between animals and monoclonal anti-digitoxin antibodies

Anti-digitoxin antibodies have been produced by immunizing rabbits and by monoclonal techniques using the same digitoxin-protein conjugate. Titres, inhibition curves, affinities, dissociation and association rate-constants have been investigated for the two antibodies. It appears that the animal immune serum gives better criteria (except specificity) than the monoclonal ones. However, both can be used for quantitative assays, with less sensitivity for the monoclonal antibody. The main advantage of monoclonal production is to conduct large amounts of specific immunoglobulins which are very useful for human administration after a digitalis overdose.

[Prognostic factors in acute digitalis poisoning]

The prognostic significance of various clinical and biochemical factors was investigated in 179 patients who had ingested more than 2 mg digitoxin. The mortality rate in this series was 17%. Supraventricular arrythmias had no influence on prognosis, but the death risk was higher in males and in patients with AV block. It increased with age, with digitoxin and potassium serum levels and even more with persistent hyperkalemia. Two other factors--previous heart disease and vomiting--were also significant in patients without heart block. Calculated on the basis of 4 clinical factors, the mortality rate varied from 2 to 74%. The death risk in acute digitalis poisoning can therefore be easily assessed simply from clinical criteria.

Prognosis and treatment of paraquat poisoning: a review of 28 cases

Paraquat poisoning is very severe. When it is ingested, this herbicide may be responsible for causative lesions of the digestive tract, cytolytic hepatitis, renal tubular necrosis, circulatory failure, and/or pulmonary fibrosis. Since a very low dose (as little as one mouthful) is potentially lethal, it is important to understand why 11 of our 28 patients who entered our department for paraquat poisoning survived. The main prognostic factors appear to be the following: Route of administration. Of four patients who had inhaled paraquat aerosols and/or contaminated their skin with the herbicide, all survived. Ingested amount. Above 50 mg/kg, patients died of circulatory failure within 72 h; between 35 and 50 mg/kg, a progressive pulmonary fibrosis occurred. Delay between ingestion and the last meal. Paraquat is adsorbed and neutralized by foodstuffs. Caustic gastric lesions revealed by early endoscopic examination. The occurrence of an organic renal failure. The plasma paraquat concentrations within the first 24 h. Patients whose plasma concentrations do not exceed 2.0, 0.6, 0.3, 0.16, and 0.1 mg/L at 4, 6, 10, 16, and 24 h, respectively, are likely to survive. The different treatments that have been tested (fuller's earth, forced diarrhea, furosemide, hemodialysis, hemoperfusion, artificial ventilation with hypoxic breathing mixtures) did not modify the initial prognosis. The 11 survivals are only linked to the circumstances of the poisonings (route of administration, ingested amount, delay between ingestion and the last meal, etc.). The treatments did not modify the outcome.

[Production of an anti-digitalin monoclonal antibody (author's transl)]

Anti-digitalin monoclonal antibodies were obtained by hybridization of lymphoid cells from mice immunized with the drug and the 8653 myeloma cells from BALB/c Mice. Two of these antibodies were submitted to immunochemical analysis which revealed that they belonged to IgM and IgGl classes, and the high affinity of one of them (1,2 x 10(9) M(-1)). The availability os such antibodies opens new perspectives for the treatment of digitalin intoxication and the possibility of establishing a standardized radioimmunoassay.

Detection and quantitation of cannabinoids in biological fluids: specificity and kinetics after smoking

A procedure for the quantitation and detection of cannabinoids in biological fluids (plasma and urine) is described. This method is based on isotopic derivatization and double labeling. delta 9-Tetrahydrocannabinol and two of its metabolites (11-hydroxy-delta 9-THC and 8-beta-hydroxy-delta 9-THC) can be detected and measured in plasma or urine. The use of TLC enables specific separation of cannabinoids. The sensitivity of detection (4 ng/mL) is compatible with cannabinoid kinetics. The procedure can be applied to routine measurements and pharmacokinetic studies.

Radioimmunoassay for colchicine: synthesis and properties of three haptens

For the development of radioimmunoassay procedures for colchicine, three haptens, N-ethylamino-colchiceinamide, 4-formylchochicine - (O-carboxymethyl) oxime and 4-hydroxymethylcolchicine O-hemisuccinic acid were synthetized and characterized by mass and proton magnetic resonance spectrometries. The conjugates obtained by coupling the haptens to bovine serum albumin were employed to immunize rabbits and goats.

[Comparative study of digoxin determination by E.L.I.S.A. and radioimmunoassay techniques (author's transl)]

This study is based on a double blind interlaboratory comparison between radioimmunoassay and E.L.I.S.A. digoxin determination. The correlation between digoxin values found with these two methods is good (r = 0.96 for therapeutic and toxic ranges 1,0 ng/ml - 5,5 ng/ml). The results indicate good repeatability, reproducibility and precision. The determination by E.L.I.S.A. can be performed with sera or plasma. The presence of haemolysis makes no appreciable difference in results. No variation is observed when different kits are used from an identical lot. However digoxin gives an important cross reactivity with digitoxin in Enzymeimmunoassay. Therefore it is necessary to know exactly the digitalis glycoside before the determination in order to avoid significant error.

[Analysis of digoxin by a radio-immunologic]

A more accurate knowledge of the effects of cardiotonic heterosides can be gained using radiocompetition. The present investigation aimed at: -comparing two commercial kits, the usual quality criteria being applied; -estimating cross-reaction between the immune systems and the endogenous as well as exogenous structural analogues; -establishing the therapeutical or toxic levels in man.

[Binding of delta-8-THC to human serum proteins: binding as a function of lipoprotein composition]

In accordance with the function of the human lipoprotein composition, using serum of different lipid profiles, the distribution of delta8tetrahydrocannabinol, as isomer of delta9THC, was studied through the use of ultracentrifugation and fraction isolation, followed by biochemical analysis of the VLDL, LDL, and HDL fractions, as well as that of the non-lipoprotein protein fraction. The results indicate the existence of a linear correlation between the distribution of delta8THC and the phospholipids of the lipoprotein cenapse. No correlation between the quantity of bound delta8THC and the other lipoprotein constituents cholesterol, triglycerides, total lipids or protein could be observed.