A direct progesterone radioimmunoassay

Résumé Exposé d'une méthode de radioimmunoassai du progestérone dans le plasma sans purification chromatographique. Le 11-hémisuccinate de la progestérone a été joint au sérum bovin de l'albumine et injecté aux lapins pour stimuler la production d'anticorps. Des échantillons de plasma humain, extraits avec de l'éther, sont ajoutés à des quantités données de 1,2-H³-progestérone. Les résultats avec ou sans chromatographie sont comparables. La méthode est précise et très sensible pour mesurer les niveaux peu élevés de progestérone humaine.     

A radioimmunoassay of vasopressin. A note on pituitary vasopressin content in brattleboro rats

Zusammenfassung Die Empfindlichkeit und Zuverlässigkeit eines neu entwickelten Radioimmunotests für Vasopressin wurde durch Messungen des Vasopressinspiegels im Hypophysenhinterlappen von homozygoten und heterozygoten Ratten für angeborenen Diabetes insipidus geprüft und eine gute Korrelation zwischen dem biologisch und radioimmunologisch gemessenen Vasopressingehalt der Hypophyse nachgewiesen.     

Impact of atypical mitochondrial cyclic-AMP level in nephropathic cystinosis

Nephropathic cystinosis (NC) is a rare disease caused by mutations in the CTNS gene encoding for cystinosin, a lysosomal transmembrane cystine/H⁺ symporter, which promotes the efflux of cystine from lysosomes to cytosol. NC is the most frequent cause of Fanconi syndrome (FS) in young children, the molecular basis of which is not well established. Proximal tubular cells have very high metabolic rate due to the active transport of many solutes. Not surprisingly, mitochondrial disorders are often characterized by FS. A similar mechanism may also apply to NC. Because cAMP has regulatory properties on mitochondrial function, we have analyzed cAMP levels and mitochondrial targets in CTNS^?/? conditionally immortalized proximal tubular epithelial cells (ciPTEC) carrying the classical homozygous 57-kb deletion (delCTNS^?/?) or with compound heterozygous loss-of-function mutations (mutCTNS^?/?). Compared to wild-type cells, cystinotic cells had significantly lower mitochondrial cAMP levels (delCTNS^?/? ciPTEC by 56%?±?10.5, P?<?0.0001; mutCTNS^?/? by 26%?±?4.3, P?<?0.001), complex I and V activities, mitochondrial membrane potential, and SIRT3 protein levels, which were associated with increased mitochondrial fragmentation. Reduction of complex I and V activities was associated with lower expression of part of their subunits. Treatment with the non-hydrolysable cAMP analog 8-Br-cAMP restored mitochondrial potential and corrected mitochondria morphology. Treatment with cysteamine, which reduces the intra-lysosomal cystine, was able to restore mitochondrial cAMP levels, as well as most other abnormal mitochondrial findings. These observations were validated in CTNS-silenced HK-2 cells, indicating a pivotal role of mitochondrial cAMP in the proximal tubular dysfunction observed in NC.     

A direct plasma testosterone radioimmunoassay

Résumé On a développé und méthode simple pour déteminer sans chromatographie en colonne le testostérone du plasma. La purification a été faite par préextraction avec l'hexane. Un antisérum contre le testostérone a été produit chez des lapins inoculés avec des conjugués de testostérone-3-oxine et d'albumine de sérum bovin.     

Effects of chronic treatment with ACTH on the intracellular levels of cyclic-AMP and cyclic-GMP in the rat adrenal cortex.

The effects of chronic ACTH treatment on the increase in the intracellular concentration of cyclic-AMP and cyclic-GMP acutely elicited by ACTH in the rat adrenal cortex were investigated. The results are consistent with the hypothesis that chronic ACTH treatment stimulates a) the de novo synthesis of adenylate- and guanylate-cyclase or b) the synthesis of new specific membrane receptors for ACTH.     

Vitamin A antibodies: Application to radioimmunoassay

Summary A radioimmunoassay for serum vitamin A is described which can detect as little as 1 ng of retinol. The statistical characteristics of this assay are presented and its use in a nutritional experiment is discussed.This work was supported by United States Public Health Service grant 2 RO1 AM19716.     

Production of antibodies to amanitins as the basis for their radioimmunoassay.

The production of antibodies against amanitins is described. By means of these antibodies, a radioimmunoassay was developed which allows detection of as little as 0.5 ng of amanitins in 1 ml of serum. By this method, the clearance of alpha-amanitin from the blood of poisoned mice was measured.     

Simplification of the ecdysteroid radioimmunoassay by the use of protein A fromStaphylococcus aureus

Summary Three methods of separating antibody-bound ligand from free ligand were compared for an ecdysteroid radioimmunoassay. Ecdysteroid antibody concentration and ligand specific radioactivity were adjusted to measure 2 ranges of ecdysone concentrations (0.01–2.0 ng and 0.25–32.0 ng). In comparison with the tradiotional separating agent, ammonium sulfate, neither protein A nor polyethylene glycol altered sensitivity or specificity of the radioimmunoassays. The protein A immunoglobulin precipitation method is quick and simple, making it a preferred alternative protocol for terminating ecdysteroid radioimmunoassays.Supported by grants AM-30118 from the National Institutes of Health and PCM-8116931 from the National Science Foundation.     

Effects of chronic treatment with ACTH on the intracellular levels of cyclic-AMP and cyclic-GMP in the rat adrenal cortex

Summary The effects of chronic ACTH treatment on the increase in the intracellular concentration of cyclic-AMP and cyclic-GMP acutely elicited by ACTH in the rat adrenal cortex were investigated. The results are consistent with the hypothesis that chronic ACTH treatment stimulates a) the de novo synthesis of adenylate- and guanylate-cyclase or b) the synthesis of new specific membrane receptors for ACTH.Part of this work was presented at the 3rd International Conference on Cyclic Nucleotides, July 1977, New Orleans, Abstr. Book, p. 79.     

Stereoselectivity of a radioimmunoassay for the insecticide S-bioallethrin

Summary The stereoselectivity of a radioimmunoassay (RIA) system using an S-bioallethrin specific antiserum was studied by observing the abilities of the 8 allethrin isomers and other selected compounds to compete with a radiolabelled S-bioallethrin tyramine derivative for antibody binding sites. The results demonstrate the feasibility of RIA as a rapid, sensitive and stereoselective residue technique for compounds difficult to analyze by classical methods.This work was supported in part by grant No. 5-R01-ES01260-02 from the National Institutes of Health.     

A radioimmunoassay for deoxycorticosterone in human peripheral plasma using sephadex LH-20 chromatography

Resumen Se reporta un nuevo método para medir desoxicorticosterona en plasma, usando cromatografía de columna LH-20 y radioinmunoensayo. Las cantidades de plasma necesarios para dicho ensayo son mínimas (2 ml) comparadas con otros métodos en la literatura, es un método practico, sensillo y rápido. Resultados así obtenidos han sido comparados con otros métodos, dichos resultados son más precisos y sensitivos para medir valores de desoxicorticosterona en plasma humano.     

Stereoselectivity of a radioimmunoassay for the insecticide S-bioallethrin

The stereoselectivity of a radioimmunoassay (RIA) system using an S-bioallethrin specific antiserum was studied by observing the abilities of the 8 allethrin isomers and other selected compounds to compete with a radiolabelled S-bioallethrin tyramine derivative for antibody binding sites. The results demonstrate the feasibility of RIA as a rapid, sensitive and steroselective residue technique for compounds difficult to analyze by classical methods.     

Transplantation of neural tissues in the brains of laboratory mammals: technical details and comments.

Various technical details on the transplantation of the embryonic neural tissues in the brains of the neonatal and adult rats are presented. Conditions determining successful or leading to unsuccessful survival, growth and differentiation of these transplants are critically examined.     

Presence of digoxin detectable by radioimmunoassay inTetrahymena

Summary Digoxin was demonstrated inTetrahymena pyriformis by radioimmunoassay, at a concentration of 4.3 ng/100,000 cells. Pretreatment of the cells with digoxin or ouabain did not significantly alter the digoxin concentration of the progeny generations.