Measurement of arachidonate and its metabolites extracted from human normal and malignant gastrointestinal tissues.

This is the first report of human gastrointestinal arachidonate and prostanoids measured quantitatively by gas chromatography-mass spectrometry (GC-MS) in extracts of human cancers and macroscopically normal tissues from the stomach and colon. There were microgram/g amounts of arachidonate, and the particularly high yield from the tumours may explain why they usually produce more prostaglandins than the normal tissues in which they arise. There was only a small conversion of the arachidonate into prostanoids.

Effect of infrared irradiation on the recoverable levels of free arachidonic acid and prostaglandins in human forearm skin.

The inside skin of the forearm of healthy volunteers was irradiated with an infrared (IR) lamp for 1 hr, resulting in the rapid appearance of an erythema and an elevation of skin surface temperature from 30 +/- 1 degree C to 38 +/- 2 degrees C within 5 min. The erythema and elevated skin surface temperature decayed within 10-30 min when the IR irradiation was stopped. Suction blisters were raised on nonirradiated skin and on irradiated skin both during irradiation and at various times after irradiation stopped.

Effect of vasoactive agents on prostanoids in suction blister fluid.

Iontophoresis of histamine in the skin has been shown to release prostaglandins and arachidonic acid in suction blister fluid. Application of DMSO had a similar effect. No effect was found after using the following erythema and oedema irritants: scraping, vibration and ketocaine.