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Biomedical subjects

H Roels

Publications and source records attributed to H Roels.

At least 163 records · Page 9Linked to original sources
PubMed1978

Experimental confirmation in rats of the mixed type proteinuria observed in workers exposed to cadmium.

Recently we have reported that the proteinuria developed by workers exposed to cadmium was characterized by an increased excretion of high and low molecular weight proteins. These observations were confirmed experimentally. Female rats which were injected intraperitoneally with CdCl2 (1 mg Cd2+/kg) 5 times a week developed after 2 months of treatment a proteinuria qualitatively similar to that observed in workers exposed to cadmium. The analysis of this proteinuria by electrophoresis and gel filtration revealed an increased excretion of low and high molecular weight proteins. This animal study, which confirms previous observations on man, strengthens our hypothesis that the cadmium-induced proteinuria, classically considered as a tubular type proteinuria, is in fact a mixed type proteinuria, involving not only the tubule but also the glomerulus.

Animals↗
PubMed1978

The influence of two barrier creams on the percutaneous absorption of m-xylene in man.

Human volunteers were exposed to m-xylene by the percutaneous route (both hands immersed into the solvent for 20 minutes). The total amount of unchanged m-xylene eliminated through the respiratory tract during and after exposure and the total quantity of m-methylhippuric acid eliminated in urine during the subsequent 24 hours were measured. The majority of absorbed m-xylene (86 to 98%) is eliminated as m-methylhippuric acid in urine. The results obtained on eight subjects who repeated the test twice indicate that under similar experimental conditions the quantity of m-xylene absorbed percutaneously by an individual may vary with time by a factor of 2 or less. The interindividual variability in the total amount of m-xylene absorbed through the skin is greater than the intraindividual variability. Among 13 subjects, the ratio between the highest and the lowest value is 6.2; the mean percutaneous absorption rate of m-xylene amounts to 2.45 microgram/cm2 x min. The application of a barrier cream containing 10% silicone did not significantly influence the rate of percutaneous absorpiton of m-xylene by 11 subjects. Preliminary results obtained of five volunteers suggest that the application of a cream containing glycerol, stearates and oleostearates was not more effective.

Adult↗
PubMed1978

Cytophotometric study of the DNA content in experimental pulmonary granuloma.

Pulmonary granulomas were induced in rabbits with Freund's complete adjuvant. Histologic alterations, the mitotic index and Feulgen-DNA amounts determined by a cytophotometric method were studied. The mitotic index and DNA amounts increased significantly within the first hours and reached peak values on the 3rd day, then showed a tendency to decrease after the 7th day. After the 3rd day, a certain dissociation was noted between the mitotic index and Feulgen-DNA amount. The change in Feulgen-DNA content reflects the functional alterations that characterize pulmonary granuloma.

Animals↗
PubMed1978

Allergic granulomatous angiitis.

A 15-year-old boy died after a 3 years' illness; asthmatic bronchitis, recurrent heart failure and eosinophilia were the essential manifestations. The autopsy elicited a diagnosis of allergic granulomatous angiitis, because of angiitis with fibrinoid necrosis and granulomatous lesions in vascular and extravascular regions. The most important differential diagnostic aspects of this disease are discussed, especially the resemblances to Wegener's granulomatosis, hypersensitivity angiitis and polyarteritis nodosa.

Adolescent↗
PubMed1978

Urinary excretion of beta2-microglobulin and other proteins in workers exposed to cadmium, lead or mercury.

For the range of exposure to heavy metals sustained by the different groups of workers, a significant increase in the urinary excretion of low and/or high molecular weight proteins was found in the workers exposed to cadmium or to lead + cadmium, but no in those exposed to lead only and those exposed to mercury. Our observations suggest that the classical "tubular" proteinuria induced by cadmium has two not necessarily concomitant components : a "tubular type" component with increased excretion of low molecular weight proteins and a "glomerular type" component with increased excretion of high molecular weight proteins.

Beta-Globulins↗
PubMed1976

Determination of manganese in blood and urine by flameless atomic absorption spectrophotometry.

A method for the determination of manganese in blood and urine is described. A chelate fo manganese with cupferron is extracted with methylisobutylketone and determined by flameless atomic absorption spectrophotometry. The method is directly applicable to urine but the determination of manganese in blood required a preliminary digestion step. With the use of internal standards, this technique allows the determination of manganese concentrations of the order of 1 mug/1 of urine or 1 mug/100 ml whole blood.

Humans↗
PubMed1976

Effect of lead on some parameters of the heme biosynthetic pathway in rat tissues in vivo.

Lead was administered to male and female rats in drinking water for 3 and 6 weeks at the following doses: 0, 10, 100, 1000, 5000 ppm and for 6 months at 10 ppm only. Various parameters of blood - lead concentration (Pb-B), hematocrit (Htc), hemoglobin (Hb), free erythrocyte porphyrins (FEB), delta-aminolevulinate dehydratase (ALAD), reticulocytes - and tissue - ALAD, free tissue porphyrins (FTP), lead concentration (Pb-T) - were determined. Pb-B increases with dose but reaches rapidly a plateau despite continuous Pb administration. Concentration of Pb in kidney, liver and brain correlates with Pb-B. Pb does not accumulate in heart. Kidney is the main site of Pb deposition and kidney ALAD is the parameter most susceptible to lead, since reduction is observed in all treated groups after 3 weeks of exposure. However, kidney ALAD inhibition is transitory since after 6 weeks it is only observed in the 5000 ppm group. At 10 ppm lead prevents also the increase in blood ALAD activity normally associated with the reticulocytosis of repetitive bleeding. The next parameters affected by lead are: ALAD in blood which is inhibited after 6 weeks of treatment with 100 ppm lead, and FEP, delta-aminolevulinic acid plus other pyrrole-forming substances in urine (ALA-U), and FTP in kidney which are increased after 3 or 6 weeks of treatment with 1000 and 5000 ppm lead.

Aminolevulinic Acid↗
PubMed1976

Effect of short-term administration of lead to pregnant rats.

Lead was administred to adult female rats in drinking water (0;0.1:1 and 10 ppm) for 3 weeks before mating, during pregnancy and during 3 weeks after delivery. On day 21 after delivery the mothers and their newborns were sacrified and various parameters of blood -- lead concentration on (Pb-B), hematocrit (Htc), hemoglobin (Hb), free erythrocyte porphyrins (FEP), delta0aminolevulinate dehydratase (ALAD) -- and tissue -- ALAD, free tissue porphyrins (FTP), lead concentration (Pb-T) -- were determined. In mothers a significant increase in Pb-B and Pb concentration in kidney was found in the 10 ppm group, but this increase in lead concentration was not associated with any statistically significant modification of the biochemical parameters. In newborns, lead concentration in blood and in kidney was also significantly increased in the 10 ppm group and this lead exposure was associated with a decrease of the ALAD activity in blood and an increase of FTP in kidney. On the basis of the biochemical parameters investigated one can therefore conclude that the developing organism is more susceptible to the biological action of lead than the organism of adult animals and that the "no-effect" level of lead administered during pregnancy and in the neonatal period is around 1 ppm.

Alanine Transaminase↗