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T J Penders

Publications and source records attributed to T J Penders.

7 recordsLinked to original sources
PubMed1989

Steroid profile for urine: reference values.

We describe a project, participated in by 24 institutions in The Netherlands and Belgium, to determine normal reference values for steroids in urine by capillary gas chromatography. Urine samples from 288 healthy volunteers were analyzed in triplicate. Reference values, expressed in mumol/24 h, were determined for androsterone, etiocholanolone, dehydroepiandrosterone, 11-keto-androsterone, 11-keto-etiocholanolone, 11-hydroxyandrosterone, 11-hydroxyetiocholanolone, pregnanediol, pregnanetriol, 11-desoxytetrahydrocortisol, tetrahydrocortisone, tetrahydrocortisol, allo-tetrahydrocortisol, and 17-keto- and 17-hydroxysteroids. We also determined reference ratios for etiocholanolone/androsterone, tetrahydrocortisone/tetrahydrocortisol, and tetrahydrocortisol/allo-tetrahydrocortisol; an upper limit of a discriminant function to establish polycystic ovarian disease; and reference values for 24-h urine volume and creatinine excretion. Reference values were determined separately for men and women, each in six age categories: 0-3 months, 4 months-12 years, 13-16 years, 17-50 years, 51-70 years, and older than 70 years. We conclude that these reference values are reliable and form a basis for quantitative interpretation of steroid profiles.

Adolescent↗
PubMed1985

Steroid profiling--an update.

Extraction of steroids from urine with C18 solid-phase extraction cartridges results in an extract containing impurities. If, during the extraction of hydrolyzed urine, an amino (NH2) column is placed in series with the C18 column, then one obtains a sample that is sufficiently clean for gas-chromatographic analysis. Analytical recovery of dehydroepiandrosterone from urine is considerably decreased by the use of increasing amounts of Helix pomatia enzyme preparation. Extraction of the steroid conjugates from urine with C18 columns before the hydrolysis stage is essential for hydrolysis with an amount of enzyme preparation that suffices for complete splitting of the polar steroid conjugates but not so much as to cause insufficient analytical recovery of dehydroepiandrosterone.

Animals↗
PubMed1984

Dihydropyrimidine dehydrogenase deficiency leading to thymine-uraciluria. An inborn error of pyrimidine metabolism.

Three unrelated patients with excessive thymine-uraciluria due to dihydropyrimidine dehydrogenase deficiency are described. Excretory values (mmol/g creatinine) were: uracil 2.0-10.5, thymine 2.3-7.5, 5-hydroxymethyluracil 0.2-0.9. Orally administered (index patient) uracil and thymine were excreted for the greater part whilst dihydrouracil and S-dihydrothymine were mainly metabolised. Dihydropyrimidine dehydrogenase activities (nmol X h-1 X mg-1 protein) in leucocytes were 0.04, 0.01 and less than 0.01 in the patients, 0.31-1.66 in their parents, and 1.01-4.46 in controls (n = 4). The patients presented with a non-specific clinical picture of cerebral dysfunction.

Adolescent↗
PubMed1968

A method for the separation of peptides and alpha-amino acids.

1. Peptides and alpha-amino acids, occurring in mixtures from various sources, can be separated into one fraction containing the amino acids and several peptide fractions. This is achieved by chelation of the mixture with Cu(2+) ions and subsequent chromatography of these chelates over the acetate form of diethylaminoethylcellulose or triethylaminoethylcellulose. 2. The amino acid fraction is obtained by elution with 0.01m-collidine-acetate buffer, pH8.0. 3. Peptide fractions are eluted with 0.01m-collidine-acetate buffer, pH4.5, 0.17n-acetic acid and 0.1n-hydrochloric acid respectively. 4. With the exception of aspartic acid and glutamic acid, which are partly found in the acidic peptide fraction, the amino acids are completely separated from the peptides. 5. Contamination of the acidic peptide fraction with glutamic acid and aspartic acid can be largely avoided by previous addition of an excess of arginine. 6. Copper is removed from the eluates by extraction with 8-hydroxyquinoline in chloroform.

Amino Acids↗