Search

The influence of ultraviolet B (UVB) irradiation on the excretion of the main urinary metabolite of prostaglandin F1 alpha and F2 alpha (PGF-MUM) in 7 normal male volunteers and 7 male patients with stable psoriasis was examined. The excretion of PGF-MUM was increased during the first 24 hours after UVB irradiation of back skin and was generally reduced to near pre-irradiation levels during the next 24 hours after irradiation, in both normal and psoriatic subjects. Although pre-irradiation levels of PGF-MUM excretion in psoriatic patients were lower than those in normal subjects as previously reported, it was demonstrated that PGF-MUM excretion after UVB irradiation in psoriatic patients was fairly increased and amounted to near the mean pre-irradiation level in normal subjects. These results suggested not only a disorder in endogenous prostaglandin synthesis in psoriatic patients but a considerable capacity of psoriatic skin to synthesize prostaglandin after UVB irradiation.

A qualitative and quantitative analysis of urinary lipids in the nephrotic syndrome is presented. The following lipids were identified in the urine of patients with the nephrotic syndrome: free cholesterol, cholesterol esters, triglycerides, free fatty acids, and phospholipids. Glass paper chromatography identified the cholesterol esters as palmitate, oleate, linoleate, and arachidonate, and identified the phospholipids as phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine. Urinary lipid excretion was much greater in patients with the nephrotic syndrome than in patients with chronic renal disease and minimal proteinuria, or in patients with hyperlipidemia from other causes. Urinary lipid excretion varied widely among the 13 patients with the nephrotic syndrome studied, and no quantitative correlation with serum lipid levels was observed. However, qualitatively at least, the proportion of cholesterol esters excreted in the urine was similar to the proportion of these esters in plasma. A good correlation was found between lipid excretion and glomerular permeability. Furthermore, during steroid therapy urinary lipid excretion decreased concomitant with a decrease in proteinuria. All these observations support the idea that lipiduria in the nephrotic syndrome is related to protein loss and that most of the lipid in the urine enters the glomerular filtrate in the form of lipoproteins.

The rate of oxidation of phytanic acid-U-(14)C to (14)CO(2) in three patients with Refsum's disease was less than 5% of that found in normal volunteers. In contrast, the rate of oxidation of alpha-hydroxyphytanic acid-U-(14)C and of pristanic acid-U-(14)C to (14)CO(2), studied in two patients, while somewhat less than that in normal controls, was not grossly impaired. These studies support the conclusion that the defect in phytanic acid oxidation in Refsum's disease is located in the first step of phytanic acid degradation, that is, in the alpha oxidation step leading to formation of alpha-hydroxyphytanic acid. The initial rate of disappearance of plasma free fatty acid radioactivity after intravenous injection of phytanic acid-U-(14)C (t(1/2) = 5.9 min) was slower than that seen with pristanic acid-U-(14)C (t(1/2) = 2.7 min) or palmitic acid-1-(14)C (t(1/2) = 2.5 min). There were no differences between patients and normal controls in these initial rates of free fatty acid disappearance for any of the three substrates tested. There was no detectable lipid radioactivity found in the plasma 7 days after the injection of palmitic acid-1-(14)C or pristanic acid-U-(14)C in either patients or controls. After injection of phytanic acid-U-(14)C, however, the two patients showed only a very slow decline in plasma lipid radioactivity (estimated t(1/2) = 35 days), in contrast to the normals who had no detectable radioactivity after 2 days. Incorporation of radioactivity from phytanic acid-U-(14)C into the major lipid ester classes of plasma was studied in one of the patients; triglycerides accounted for by far the largest fraction of the total present between 1 and 4 hr.

Two sibs with heredopathia atactica polyneuritiformis (Refsum's Disease) each had a relapse after ceasing to follow a special diet. On being placed on a very restricted low phytol, low phytanic acid diet both had marked subjective improvement, and marked objective improvement both in physical findings and in quantitative tests of strength, dexterity, and motor nerve conduction velocities, concomitant with a fall in serum phytanic acid levels. No relapse occurred in 22 months on this diet.