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Biomedical subjects

H G Meyer

Publications and source records attributed to H G Meyer.

28 records · Page 2Linked to original sources

A radioimmunoassay for pyridostigmine.

Antipyridostigmine antibodies were produced in rabbits using a pyridostigmine analog conjugated to keyhole limpet hemocyanin. These antibodies were used for development of a radioimmunoassay that has a linear standard curve (r2 = 0.986) ranging from 0.5 to 10.0 ng/ml of pyridostigmine bromide in a 0.1-ml plasma sample. This assay measures pyridostigmine in plasma with better sensitivity and much greater through-put than do current state-of-the-art high-performance liquid chromatography techniques. In addition, only small volumes (100 microliter) of the plasma samples are required. Plasma levels of pyridostigmine were determined in the rat after intramuscular administration (0.056 mg/kg) of pyridostigmine bromide. Estimates of the various pharmacokinetic parameters were calculated using the computer program NONLIN84. The results were as follows: apparent volume of distribution = 1.97 l/kg, absorption rate constant = 0.277 min-1, elimination rate constant = 0.0273 min-1, area under the curve = 1010 ng x min/ml, absorption rate half-life = 2.41 min, elimination rate half-life = 24.8 min, maximal plasma concentration (Cmax) = 21.3 ng/ml and time to Cmax = 9.02 min.

Algorithms↗

Spontaneous reactivation of phosphinylated human erythrocyte acetylcholinesterase and human serum butyrylcholinesterase.

This report documents studies on the spontaneous reactivation of human erythrocyte acetylcholinesterase and human serum butyrylcholinesterase following inhibition by organophosphinate esters. The spontaneous reactivation reactions were carried out at 26.0 degrees C in 0.10 M phosphate buffer of pH 7.6. Based upon results at 24 h, human serum butyrylcholinesterase inhibited with 4-nitrophenyl methyl (4-methoxyphenyl) phosphinate was the most responsive (92.5% recovery) of the nine esters studied. Using the same criteria, the most active compound in the human erythrocyte acetylcholinesterase studies was 4-nitrophenyl methyl(phenyl)phosphinate (74.2% recovery). With seven of the nine compounds examined the response was greater from the serum enzyme than from the erythrocyte enzyme.

Acetylcholinesterase↗

[Multicenter study of the results of the extraction of transvenously implanted heart-pacemaker electrodes using continuous traction].

The continuous traction of firmly grown-in collar electrodes from the right ventricle is a simple technique poor in complications with a high success rate, which can be recommended taking into consideration the indications in the failure of the immediate manual extraction and which can be performed in every centre for cardiac pacemakers. Apart from the consideration of adequate informations in literature this evidence above all depends on the evaluation of data of 29 cases from 10 centres for cardiac pacemakers.

Adult↗

Specificity of the immunocytochemical luteinizing hormone-releasing hormone receptor reaction.

Affinity-purified anti-LHRH, affinity-purified LHRH-anti-LHRH complex, as well as antisera depleted of anti-LHRH by solid phase immunoabsorption were used to test the specificity of the immunocytochemical approach for detection of receptor-bound LHRH. The solid phase immunoabsorbent was prepared by attaching LHRH to Sepharose via an RNase spacer. Purified anti-LHRH was eluted from the immunoabsorbent by acidification. Unabsorbed antisera as well as purified antibody conferred moderate immunocytochemical staining to the secretion granules of rat pituitary gonadotrophs. Staining intensity became greatly increased upon treatment of the electron microscopic sections with LHRH before immunocytochemical staining. All gonadotroph staining was abolished when absorbed antisera were used. The specificity of the immunoabsorbent was tested on mixtures of anti-LHRH and anti-ACTH17-39. On absorption of such mixtures with insolubilized LHRH, all gonadotroph staining disappeared, but the optical density indices of ACTH staining remained unaffected. It is concluded that gonadotroph secretion granules contain, in addition to an LHRH receptor reacting with LHRH in vitro, stable complexes of endogenous LHRH with receptor.

Adrenocorticotropic Hormone↗

Mixed lymphocyte culture responses in infertile couples.

Twenty couples suffering from unexplained infertility have been tested in mixed leucocyte culture to determine if the wives were preimmunized against their husbands. The wives were tested against their husbands and four unrelated persons, and thymidine incorporation was measured on the third and fifth days of culture. No evidence was found that would indicate a preimmunization of the wife against her husband as an explanation for their infertility. A slight MLC stimulatory capacity was found in sera from infertile women.

Culture Media↗