PGE1 compared to PGE2/PGF2 alpha ratio as a marker for seminal fluid contamination of urine in studies of renal prostaglandin biosynthesis

Effect of n-3 fatty acid supplementation on urinary risk factors for calcium oxalate stone formation

PURPOSE

Findings are inconsistent in a few studies of the effect of n-3 fatty acid supplementation on urinary calcium and oxalate excretion in stone formers. We evaluated the physiological effects of supplementation with eicosapentaenoic acid and docosahexaenoic acid on urinary risk factors for calcium oxalate stone formation under standardized conditions.

MATERIALS AND METHODS

We studied 15 healthy subjects initially while consuming a standardized diet for 5 days (control phase). During consecutive intervention phases 1-5-day standardized diet, 2-20-day free diet and 3-5-day standardized diet participants received 900 mg eicosapentaenoic acid and 600 mg docosahexaenoic acid daily. While ingesting the standardized diets, daily 24-hour urine samples were collected.

RESULTS

After short-term supplementation with eicosapentaenoic acid and docosahexaenoic acid in phase 1 we noted no changes in urinary parameters compared to the control phase. After 30-day supplementation with eicosapentaenoic acid and docosahexaenoic acid in phase 3 relative supersaturation with calcium oxalate decreased significantly by 23% from a mean ± SD of 2.01 ± 1.26 to 1.55 ± 0.84 due to significantly decreased urinary oxalate excretion (p = 0.023). Other urinary variables were not affected by supplementation.

CONCLUSIONS

Results show that 30-day n-3 fatty acid supplementation effectively decreases urinary oxalate excretion and the risk of calcium oxalate crystallization. The mechanism of the physiological effect may be decreased cellular oxalic acid exchange attributable to an altered fatty acid pattern of membrane phospholipids with concomitant changes in oxalate transporter activity. Calcium oxalate stone formers may benefit from long-term n-3 fatty acid supplementation.

Prostaglandin E2 measurements: their value in the early diagnosis of heterotopic ossification in spinal cord injury patients

OBJECTIVE

To look for a possible relation between the occurrence of heterotopic ossification (HO) and the modifications of the 24-hour prostaglandin E2 (PGE2) urinary excretion.

DESIGN

A 5-year prospective study to determine the 24-hour urinary excretion of PGE2 by radioimmunoassay with specific antisera not cross-reacting with TXA2, TXB2, 15-keto-PGE2 alpha, PGI2, 6-keto-PGF1 alpha.

SETTING

The laboratory of a division of endocrinology and diabetology of a university hospital.

PATIENTS

Of 262 acute spinal cord injury patients screened, 44 were eligible for the study.

INTERVENTIONS

Serial diagnostic quantitative bone scannings with technetium 99m Tc methylene diphosphate (99mTc-MDP) and therapeutic assessment of radiotherapy and indomethacin.

MEAN OUTCOME MEASURE

Hypothetical increase of PGE2 before and during HO formation.

RESULTS

Of 44 patients, 8 developed an HO (18.8%) with concomitant marked increase of the PGE2 excretion for as long as the HO had not reached maturity. The results of the radiotherapy were inconclusive. Indomethacin was shown to be efficacious in holding back or slowing down the HO evolution.

CONCLUSIONS

Measurement of the 24-hour PGE2 urinary excretion appears to be a valuable indicator in the early diagnosis of HO. Indomethacin should be considered as an alternative to other existing therapies.

Liquid chromatography and radioimmunoassay method for the determination of prostaglandins E1 and E2 in rat embryo incubates

This paper describes the application of a combined high-performance liquid chromatography and radioimmunological assay method for the measurement of prostaglandins E1(PGE1) and E2(PGE2). Samples were acidified to pH 3.15, extracted twice with ethyl acetate and further processed through C18 solid-phase extraction cartridges. After HPLC purification, PGE1 and PGE2 were measured by radioimmunological techniques. The limit of detection for PGE1 was 3.9 pg/ml and the intra-assay relative standard deviation was 7.8% for n = 5. The accuracy of the assay procedure was also verified. The method has been applied to the determination of PGE1 and PGE2 in embryo incubates from 10-day pregnant rats.