The concentration of free and conjugated 3-hydroxyanthranilic acid in the urine of bladder tumour patients before and after therapy, measured with an enzymatic method

The basal concentration of the tryptophan metabolite 3-hydroxyanthranilic acid (3OHA), which has carcinogenic properties, was measured with an enzymatic method of determination which allowed separate measurement of free and conjugated 3OHA. The concentration of free 3OHA in untreated bladder cancer patients was significantly (P <0·001) higher than in a healthy control group, but after local therapy the concentration was significantly lower than before treatment (P <0·01). The concentration of conjugated 3OHA was nearly constant in the three groups. It was concluded that other factors than a genetic determined abnormality might be operating in bladder cancer patients which could lead to an abnormal concentration of 3OHA in their urine.

The generation from arachidonic acid of rabbit aorta contracting substance (RCS) by a microsomal enzyme preparation which also generates prostaglandins

1. Sodium arachidonate was incubated with a crude prostaglandin synthetase preparation made from dog spleen. The incubation was made in a dynamic system so that the products could be delivered to strips of rabbit aorta and rat stomach.2. A rabbit aorta contracting substance (RCS) and a prostaglandin-like substance were formed. The RCS had similar properties to that released in anaphylaxis. It was unstable and as the RCS activity declined, so the prostaglandin-like activity increased. Its formation was prevented by prostaglandin synthetase inhibitors such as indomethacin.3. A different rabbit aorta contracting substance was formed by incubation of arachidonate with lipoxygenase, which generates peroxides. This substance was stable and did not lead to prostaglandin production.4. We conclude that RCS may be an intermediate in prostaglandin production, such as the postulated cyclic endoperoxide.

The origin and structures of dimeric fatty acids from the anaerobic reaction between soya-bean lipoxygenase, linoleic acid and its hydroperoxide

In an anaerobic system soya-bean lipoxygenase catalyses in the presence of linoleic acid and l-13-hydroperoxyoctadeca-cis-9-trans-11-dienoic acid the formation of dimeric fatty acids and of carbonyl compounds. The analogous reaction does not take place when d-9-hydroperoxyoctadeca-trans-10-cis-12-dienoic acid is used instead of the 13-hydroperoxy isomer. Non-oxygenated dimers stem directly from linoleic acid and have C((11))-C((13')) or -C((9')) and C((13))-C((13')) or -C((9')) linkages. Dimers that contain oxygen originate from linoleic acid and linoleic acid hydroperoxide. It is most likely that the oxygen is present in epoxy groups.

The bacterial oxidation of picolinamide, a photolytic product of Diquat

The pathway of oxidation of picolinamide (pyridine-2-carboxamide) by a Gram-negative rod has been elucidated. Under conditions of high pH, restricted aeration and high substrate concentration, whole cells released 2,5-dihydroxypyridine into culture supernatants. Sodium arsenite at 5mm caused whole cells to accumulate 6-hydroxypicolinate, and, at 1mm, pyruvate, in culture media. Whole cells oxidized picolinamide, picolinate, 6-hydroxypicolinate, maleamate and maleate without lag. Cell-free extracts converted picolinamide into picolinate, and hydroxylated picolinate to 6-hydroxypicolinate. The hydroxylase was particulate, but could be solubilized by ultrasonic treatment; it required NAD(+) for activity, and did not require molecular oxygen. 2,5-Dihydroxypyridine was converted into maleamate and formate by an oxygenase requiring GSH and Fe(2+). Maleamate was deamidated to maleate, and maleate isomerized to fumarate, by unsupplemented extracts.