Biomedical subjects
Publications and source records attributed to J Pilliod.
The value of the glycosaminoglycans (GAG) determination in urine was examined in a population of hydrocarbon-exposed workers and compared to the usefulness of the fractional albumin clearance (FAC). Blood pressure and hydrocarbon exposure interact to increase the FAC but the GAG concentration seems less useful because too many other variables influence it as well.
When large arrays of strange attractors are coupled diffusively through one of the variables, chaotic systems become periodic and form large archimedean spirals or concentric bands. This observation may have importance for many applications in the field of deterministic chaos and seems particularly relevant to the question of the formal temporal structure of the biological clock in metazoan organisms. In particular, although individual cellular oscillators, as manifested in the cell cycle, may have deep basins of attraction and appear to be more or less periodic, we suggest that cells oscillate with chaotic dynamics in the ultradian domain. Only when large aggregates of these cells are tightly coupled can a precise circadian clock emerge. For changing coupling strength or parameter values, period increase occurs through quantal or integral multiple increments of the fundamental. All calculations were implemented on a 386AT, using a Mercury MC6400 floating point processor.
As part of a study on the possible nephrotoxicity of hydrocarbons, the urinary erythrocyte concentration and the percentage of glomerular erythrocytes were assessed. Albumin excretion rate, glycosaminoglycan and retinol-binding protein concentration, and N-acetyl-beta-glucosaminidase activity were measured simultaneously. The results show that the erythrocyte concentration and the percentage of glomerular erythrocytes tend to increase with hydrocarbon exposure, and that a nephrotoxic effect of occupational hydrocarbon exposure deserves consideration.
Control and hydrocarbon exposed workers participated in a cross-sectional study about the nephrotoxicity of chronic hydrocarbon exposure. Different markers of glomerular and tubular function as well as the celluria were examined and compared. The results show that the interaction between hypertension and hydrocarbon exposure has an influence on the kidney function. For the clearance the interaction age-exposure seems to play a more important role than age or exposure alone. The most useful markers appear to be the albuminuria, the N-acetyl-beta-D-glucosaminidase activity, the retinol-binding-protein concentration and the creatinine clearance.
The data on hydrocarbon induced pancreatitis are conflicting. This question was therefore studied in a non-selected population exposed to hydrocarbons and in "formerly" exposed workers. Neither the past clinical history nor the pancreatic tests provided any evidence for a causal relation between exposure and pancreatitis. No signs of hydrocarbon induced liver damage were seen either. As a healthy worker effect cannot be totally excluded, however, a case-control study in a group of patients suffering from non-alcohol induced pancreatitis could give useful indications for finally excluding the possibility of pancreatitis being induced by hydrocarbons.
In case-control studies on glomerulonephritis and organic solvents several authors have assessed exposure to organic solvents with a score based on the self reported occupational history. The underlying principle is that all exposures can be weighted by an intensity factor and then added to get one number representative of lifetime exposure. As this score has hitherto not been validated the relation between this exposure score and kidney function tests in a population of workers with past or present exposure to organic solvents was examined. The results suggest that such relations do exist for the N-acetyl-beta-D-glucosaminidase (NAG) activity, erythrocyturia, and, perhaps, albuminuria but not for the protein creatinine ratio or for leucocyturia.
The value of glycosaminoglycans determination in urine has been challenged because the relation between the glycosaminoglycans concentration and other signs of kidney damage is a matter of controversy. It is quite possible that the observed discrepancies could be due to the influence of the urine flow rate, the urine concentration and the time of day on the glycosaminoglycans concentration. Therefore, standardization of the urine sampling time and selection of the most appropriate unit to quantify glycosaminoglycans excretion seem to be essential.