Decrease in S-adenosylmethionine synthesis by 6-mercaptopurine and methylmercaptopurine ribonucleoside in Molt F4 human malignant lymphoblasts.

6-Mercaptopurine (6-MP) and methylmercaptopurine ribonucleoside (Me-MPR) are purine anti-metabolites which are both metabolized to methylthio-IMP (Me-tIMP), a strong inhibitor of purine synthesis de novo. Me-MPR is converted directly into Me-tIMP by adenosine kinase. 6-MP is converted into tIMP, and thereafter it is methylated to Me-tIMP by thiopurine methyltransferase, an S-adenosylmethionine (S-Ado-Met)-dependent conversion.

Reference values for amino acids in cerebrospinal fluid of children determined using ion-exchange chromatography with fluorimetric detection.

One thousand specimens of CSF were collected from subjects ranging in age from newborn to 18 yr, who were undergoing a diagnostic lumbar puncture. Sixty-two samples were judged retrospectively as being suitable for calculating reference age-related values. The analyses were performed by an amino acid analyser using ion-exchange chromatography with fluorimetric detection giving a tenfold increase in sensitivity, thereby enhancing the diagnostic capabilities.

Urinary excretion of hydroxylysine and its glycosides in normal persons of different ages--influence of maturation.

Basement membrane collagen is relatively rich in hydroxylysine and the glycosides of hydroxylysine, glucosylgalactosylhydroxylysine and galactosylhydroxylysine. In this paper a modified procedure for analysis of these substances in urine is described, using a purification-step with the cation-exchange resin Amberlite CG-120 type II and a modified program for amino acid analysis. Values are obtained from 75 healthy persons of different ages ranging from prematurity to adulthood.