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Biomedical subjects

A E Gal

Publications and source records attributed to A E Gal.

At least 37 records · Page 2Linked to original sources

Synthesis of 2-n-(hexadecanoyl)-amino-4-nitrophenyl phosphorylcholine-hydroxide, a chromogenic substrate for assaying sphingomyelinase activity.

2-N-(Hexadecanoyl)-amino-4-nitrophenyl phosphorylcholine-hydroxide a compound resembling sphingomyelin is synthesized. It is cleaved by sphingomyelinase to the chromogenic N-acylaminonitrophenyl moiety. Phospholipase C preparations do not hydrolyze this compound. The starting material is 2-amino-4-nitrophenol which when acylated with palmitoyl chloride yields the hexadecananilide. Reaction with beta-bromoethylphosphoryldichloride gives the phosphate which is quaternized with trimethylamine to give the title compound.

Magnetic Resonance Spectroscopy↗

A practical chromogenic procedure for the detection of homozygotes and heterozygous carriers of Niemann-Pick disease.

Niemann-Pick disease is caused by a deficiency of sphingomyelinase in organs and tissues. Determinations of sphingomyelinase activity had required the use of sphingomyelin labeled with radiocarbon or radiohydrogen. These materials are expensive, and their use is restricted to laboratories with radioactive counting facilities. An analogue of sphingomyelin, 2-hexadecanoylamino-4-nitrophenylphosphorylcholine, was synthesized. This substance is hydrolyzed by highly purified sphingomyelinase, and by sphingomyelinease in extracts of human liver tissue, cultured skin fibroblasts, cultured amniotic cells and washed leukocyte preparations. Extracts of tissues and cells from patients with Niemann-Pick disease Type A do not hydrolyze this compound, whereas heterozygotes and patients with Niemann-Pick disease Type C have an intermediate level of hydrolytic activity. Thus, the analogue is a reliable chromogenic reagent for the diagnosis of patients with Niemann-Pick disease and the detection of heterozygous carriers of the Niemann-Pick trait.

Amniotic Fluid↗