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Biomedical subjects

N Jordan

Publications and source records attributed to N Jordan.

At least 55 records · Page 3Linked to original sources
PubMed1984

Quantitation of delta 4-reduced metabolite of norethindrone in human plasma by HPLC-RIA.

An HPLC-RIA method for the measurement of the delta 4-reduced metabolite of norethindrone is described. The sensitivity of the method was such as to permit the quantitation of pg amounts (30 pg with an inter-assay CV of less than 7%). Nineteen volunteers received a single oral dose of 1 mg of norethindrone and, blood samples withdrawn at timed intervals, were pooled for each time period and assayed. The plasma concentrations of the dihydro metabolite ranged from 460 pg/ml at 30 min to 20 pg/ml at 24h.

Biotransformation↗
PubMed1983

HPLC-RIA of a metabolite of norethindrone in human plasma, 17 alpha-ethinyl-5 beta-estrane-3 alpha, 17 beta-diol, following conjugate hydrolysis.

An HPLC-RIA method for the assay of a reduced metabolite of norethindrone, 17 alpha-ethinyl-5 beta-estrane-3 alpha, 17 beta-diol, is described. Conjugated metabolites were extracted from human plasma and subjected to hydrolysis prior to analysis. With a daily dose of 2 mg of norethindrone, the mean plasma level of the metabolite was 24.8 ng/ml with a range of 22.8 ng/ml to 33.9 ng/ml.

Chromatography, High Pressure Liquid↗
PubMed1983

Norethindrone antisera: anomalous cross-reactivities with use of 3H-tetrahydro-reduced norethindrone as radioligand.

Anomalous cross-reactions with the dihydro- and tetrahydro-reduced metabolites of norethindrone were observed utilizing antisera raised against norethindrone-3-bovine serum albumin. Whereas displacement of 3H-norethindrone from the antiserum by the metabolites was generally minimal, where one of the metabolites was used as radiotracer, displacement by the metabolites was equal to or greater than that achieved by norethindrone. This unexpected finding was examined for its usefulness in developing a radioimmunoassay system for norethindrone metabolites in plasma. The sensitivity of the resulting standard curve was such as to permit quantitation of pg amounts of the reduced metabolites.

Animals↗
PubMed1981

Identification of hydrazone of norethindrone, a metabolic product resulting from the interaction between isoniazid and norethindrone.

Co-administration of isonicotinic acid hydrazide (isoniazid, INH) and 17 alpha-ethinyl-17 beta-hydroxyestr-4-en-3-one (norethindrone, NE) resulted in the formation of the isonicotinyl hydrazone of norethindrone (INH-NE) in rat stomach. Rat liver metabolized the latter compound in vitro. The metabolic product was characterized, following its derivatization with p-methoxy-benzaldehyde (PMBA), by comparison of chromatographic and mass spectral properties with synthetic reference compound. Results showed that INH-NE was cleaved at the amide bond resulting in the formation of the hydrazone of norethindrone. The physicochemical characteristics of synthetic PMBA hydrazone of norethindrone are described.

Animals↗
PubMed1979

A radio-immunological assay for triamcinolone in plasma.

A specific radioimmunoassay for the determination of picogram quantities of triamcinolone in plasma is reported. A rapid chemical separation method was incorporated in the procedure to remove the interfering endogenous hydrocortisone which cross reacts (5%) with the antiserum. Application of this radioimmunoassay to the analysis of triamcinolone plasma concentrations following oral administration of a 5 mg dose of the drug to a human volunteer is described.

Animals↗
PubMed1978

A specific radio-immunological assay for prednisolone in plasma.

A new, specific radio-immunological assay (R.I.A.) for prednisolone in plasma is described. The R.I.A. incorporates a procedure whereby the endogenous interfering hydrocortisone (in de-proteinized plasma) reacts directly with Girard Reagent T, resulting in a derivative which does not cross react with the specific antibody for prednisolone. The assay is sensitive (quantitation levels are in the 5-10 ng/ml range). The specificity compares favorably with that of a high performance liquid chromatographic procedure.

Animals↗
PubMed1977

Analysis of prednisolone in plasma by high-performance liquid chromatography.

A sensitive, specific high-performance liquid chromatographic procedure for the determination of prednisolone in plasma is described. The organic solvent extract from plasma is chromatographed on a silica gel column using a mobile phase of 0.2% glacial acetic acid, 6% ethanol, 30% methylene chloride in n-hexane on a high-performance liquid chromatograph fitted with an ultraviolet dector (254 nm). Quantitation of plasma samples containing 25 ng/ml prednisolone is reported. Metabolites and endogenous hydrocortisone do not interfere with prednisolone. The determination of prednisolone concentration in plasma following administration of a 10-mg single oral dose to a human subject is described.

Chromatography, High Pressure Liquid↗
PubMed1977

Objective determinations of sensibility in the upper extremity. Part I. Median nerve sensory conduction velocities.

Distal sensory conduction velocities were determined in 109 normal median nerves. A significant decrease in sensory conduction velocity was noted with increasing age. Latencies increased with age but this relationship was not significant in men. Variables which contribute to the wide range of normal conduction velocities are discussed, and the need for each clinician to establish his own testing procedure is stressed. An additional method for assessing sensory function is suggested.

Adult↗
PubMed1977

Objective determinations of sensibility in the upper extremity. Part II. Application of cutaneous stimuli in control subjects.

Sensitization statements were read to two groups of normal subjects to determine whether quantifiable thresholds for pressure, electrical, or tactile stimuli could be altered. Significant reductions in perception thresholds were observed for pressure and digital pulsed stimulation, but not for stimulation to the discomfort threshold, or two point discrimination. These data seem to suggest that increased sensitization is related to the ease of stimulus applications and the comparative simplicity of sensory processing.

Adult↗
PubMed1977

Objective determinations of sensibility in the upper extremity. Part III. Application of cutaneous stimuli in patients with peripheral nerve lesions.

Quantitative values for pressure, electrical, and two-point touch stimulation were examined in five patients with peripheral nerve injuries of the ulnar or median nerves. Analyses of profiles generated for each stimulus application in each patient participating in this preliminary study suggest that, following the reading of a sensitization statement, pressure and electrical shock threshold values are clearly reduced compared to similar measurements in the unaffected limb. Values obtained prior to the statement indicated progressively reduced thresholds, however. Changes in sensation appear to precede significant improvements in sensory nerve conduction velocity. Limitations in the sensory testing techniques as well as suggestions for improving its validity are discussed.

Adult↗
PubMed1977

Quantitation of digoxigenin in serum following oral administration of digoxin in humans.

Separation of the acid breakdown products from digoxin in serum was accomplished by high performance liquid chromatography (HPLC). The major, less cardioactive, product digoxigenin was quantitated by several different commercial antisera from digoxin radioimmunoassay (RIA) kits. When two normal subjects were given digoxigenin (0.5 mg) orally appreciable concentrations were detected by digoxin RIA kit. Administration of a digoxin (0.5 mg) solution to the same overnight-fasted recumbent volunteers resulted in digoxigenin detection (HPLC-RIA) in serum only in one subject.

Administration, Oral↗
PubMedDate not supplied

Pharmacokinetic evaluation of betamethasone and its water soluble phosphate ester in humans.

Two betamethasone tablet formulations, and betamethasone phosphate solution were compared in a plasma level study. The tablet formulations (A and B) and a solution of betamethasone phosphate (C) were administered in single 2 mg doses to nine volunteers according to a three times repeated Latin square design. Plasma samples were obtained over 72 h following each dose and plasma was analysed for betamethasone by radioimmunoassay. Pharmacokinetic evaluation of the data, obtained according to the one-compartment open model, indicated that there were no significant differences between the extent of absorption, and the first-order elimination rate constants. As would be expected, the solution (C) gave a faster absorption rate than tablets A and B.

Adult↗