Short term variation of human immunoglobulin levels with an estimation of the day to day physiological variability.

In this work serum Ig levels were determined daily for 14 days in 12 subjects, every two days for 14 days in 19 subjects, every week for 1 month in 11 subjects and fortnightly in 11 subjects for 6 months. The serum IgG, IgM and IgA levels were quantitated by the linear plate method. The day-to-day reproducibility of the technique was checked for a period of one months on seven different samples. The mean coefficient of variation in the reproducibility experiments was found to be 4.8% for IgG, 8.2% for IgM and 5.2% for IgA. Since the observed variation in all groups of subjects was found to be higher than the methodological variation, it appears that physiological variability occurs in the serum Ig levels of an individual. No difference was found between the physiological variances of IgG, IgM and IgA observed in the group with daily analysis and those with determinations every two days. The physiological variations increase when longer periods are considered between consecutive determinations, but the variability of IgG and IgA in the group with fortnightly determinations is less important than that observed in the group with weekly analyses. Some evidence is presented indicating a periodic fluctuation of serum IgG and IgA levels with an amplitude of nearly 20% and with a recurrence rate of two weeks.

Avascular necrosis and its relation to lipid and purine metabolism.

Serum uric acid, triglycerides, cholesterol, and lipoprotein levels were determined in 35 patients with primary avascular necrosis of the femoral head. The results were compared with a control group and a group of gouty patients. Frequency distribution of the data in the three groups was found to be of the log normal type, and the statistical calculations were performed after log transformation of the serum values. Compared to the control group, a significant increase in the levels of triglycerides, cholesterol, pre-beta-lipoprotein, and uric acid were found in the patients with avascular necrosis. No significant difference was observed between lipid and lipoprotein levels in gout and avascular necrosis, although the serum uric acid was higher in the gouty patients. In contrast to the findings in gout, the uric acid levels did not correlate with the lipid or lipoprotein fractions in patients with avascular necrosis. There were no statistical differences between lipid, lipoprotein and uric acid levels in patients with avascular necrosis receiving corticosteroids or using alcohol, as compared with those not taking these drugs. It is concluded that avascular necrosis of bone complicating longterm use of steroids or alcohol is not induced directly by the two drugs, but that the initiating event may lie in lipid disturbances.

[Relationship between avascular necrosis and lipid and purine metabolisms]. / Relations entre la nécrose avasculaire et le métabolisme des lipides et des purines. Corrélations entre les taux d'acide urique, des lipides et des lipoprotéines dans la goutte et la nécrose avasculaire

The serum levels of uric acid, triglycerides, cholesterol, and lipoproteins were determined in 35 patients suffering from primary avascular necrosis. The results were compared with those of a control group and with those of patients suffering from gout. The frequency distribution of the results in the three groups was of the log-normal type and statistical calculations were made on logarithmic transformations of the serum values. In comparison with the control group, significant increases in the levels of triglycerides, cholesterol, pre-beta-lipoproteins, and uric acid were observed in patients presenting an avascular necrosis. No significant differences were observed between these patients and patients with gout in the levels of lipids and lipoproteins. Uricaemia was higher in the gout patients. Contrary to observations made on the gout patients, there was no correlation in the avascular necrosis patients between the uric acid level and the serum levels of lipids or lipoproteins. In an earlier study the authors put forward an hypothesis according to which the close relationship between the lipid and purine metabolisms in gout patients was due to a genetic linkage based on a common enzyme defect, which directly affected the two metabolisms. In avascular necrosis there is no common enzyme defect; the initial event is a disturbance in the lipid metabolism. The authors conclude with data which tend to show that the bone necrosis observed in patients using steroids or alcohol is not directly induced by these substances, but that once again the initial event is a disturbance in the lipid metabolism.