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Biomedical subjects

R Cornelis

Publications and source records attributed to R Cornelis.

At least 37 records · Page 2Linked to original sources
PubMed1996

Basal metabolism of intraperitoneally injected carrier-free 74As-labeled arsenate in rabbits.

The time-dependent occurrence of [74As]arsenate metabolites in Flemish Giant rabbits was investigated. As absorbed rapidly, reaching maximal concentrations in plasma and packed cells after 30 min and 2 hr, respectively. The [74As]arsenate in plasma and packed cells was reduced to [74As]arsenite, to 35 and 50% of the total 74As, respectively. The concentration of methylated As species in plasma and packed cells increased rapidly after 30 min. About 18% of total plasma 74As maximally bound to transferrin. Two-thirds of total 74As in packed cells bound to hemoglobin. Whereas little or no [74As]monomethylarsonic acid, one of the main As metabolites in humans, could be found in other animals, it is present in measurable amounts in the Flemish Giant. Furthermore, the plasma clearance rate of 74As species is lower than that in other rabbits and more similar to that of humans. The tissue 74As distribution varied widely with the highest concentrations in kidneys, liver, and lungs. 74As accumulated in bone whereas other tissues and blood showed rapid clearance rates. In muscle and heart an important part of arsenic was associated with components insoluble in phosphate-buffered isotonic saline. Binding of arsenic to soluble tissue proteins was most important in the kidneys, liver, and spleen. [74As]Arsenate metabolites were detected in all tissues. The relative amounts of [74As]arsenite or [74As]monomethylarsonic acid seldom exceeded 15% of total tissue 74As. The proportion of [74As]dimethylarsenic acid in the low molecular 74As fraction increased steadily. Substantial amounts of [74As]monomethylarsonic acid were found in the tissues..

Animals↗
PubMed1996

Sample collection guidelines for trace elements in blood and urine. IUPAC Commission of Toxicology.

This paper presents an organized system for element-specific sample collection and handling of human blood (whole blood, serum or plasma, packed cells or erythrocytes) and urine also indicating a proper definition of the subject and sample. Harmonized procedures for collection, preparation, analysis and quality control are suggested. The aim is to assist scientists worldwide to produce comparable data which will be useful on a regional, national and international scale. The guidelines are directed to the elements aluminium, arsenic, cadmium, chromium, cobalt, copper, lead, lithium, manganese, mercury, nickel, selenium and zinc. These include the most important elements measured for their occupational or clinical significance, and serve as examples of principles that will guide development of methods for other elements in the future.

Blood Specimen Collection↗
PubMed1996

Transperitoneal absorption and kinetics of chromium in the continuous ambulatory peritoneal dialysis patient--an experimental and mathematical analysis.

The functional model of Cr kinetics and metabolism described by Lim et al. [Am J Physiol 1983; 224:R445-R454] for healthy people was adapted to the specific situation of the continuous ambulatory peritoneal dialysis (CAPD) patient. For this purpose 3 CAPD patients were submitted to an acute 51Cr-labelled dialysis dwell of 6 h. The rate of uptake of Cr in the plasma appeared to be equal to its disappearance rate from the peritoneal fluid. The plasma levels increased to a constant value in the first 2 h after the start of the dialysis session. The amount of Cr cumulatively excreted in the urine over the follow-up period of 10-12 days was 10-15% of the amount absorbed during the acute dwell. The experimental pharmacokinetic data were in close agreement with the values predicted by the modified functional model for Cr(III) kinetics and metabolism. According to this model, the effect of long-term CAPD treatment (10 years) should result in an accumulation of Cr with a factor of 100 in those organs, especially liver and spleen, known to have a slow exchange of Cr with the central plasma compartment. This predicted and dramatic increase was in close agreement with the Cr concentrations found in liver tissue of 3 patients who died after a variable time on CAPD.

Absorption↗
PubMed1996

Accumulation of arsenic species in serum of patients with chronic renal disease.

Speciation of arsenic was determined in serum of 19 non-hemodialysis (non-HD) and 18 HD patients. The respective mean values of serum creatinine in these groups were 410 +/- 250 and 914 +/- 173 mumol/L (reference range for healthy subjects: females 50-80; males 57-93 mumol/L). The mean total arsenic concentrations were 5.12 +/-5.58 and 6.47 +/- 4.28 micrograms/L, respectively (reference value: 0.958 +/-1.52 micrograms/L). Dimethylarsinic acid (DMA) and arsenobetaine (AsB) were the major As species in serum of the non-HD and HD patients, with mean values of 0.82 +/- 1.05 and 1.93 +/- 1.51 micrograms/L for DMA and 3.55 +/- 4.58 and 3.47 +/- 2.89 micrograms/L for AsB, respectively. Serum concentrations of inorganic As and monomethylarsonic acid in both groups were below the detection limits for these compounds. Measurement of As concentration before vs after 4 h of HD treatment indicated that 68% of total As in serum was removed, as was 16% of the total As in packed cells. The efficiency of DMA and AsB removal during dialysis corresponded to that of total As.

Adult↗
PubMed1995

Study of the chromium binding in plasma of patients on continuous ambulatory peritoneal dialysis.

The distribution of chromium (Cr) among the proteins in plasma of three continuous ambulatory peritoneal dialysis (CAPD) patients and in dialysis solutions was studied with 'in vitro' and 'in vivo' 51Cr-labelled plasma. Radiolabelling allows the kinetics of newly added Cr to be investigated. The separation of the proteins was achieved by ion exchange fast protein liquid chromatography, ensuring quantitative recoveries of the 51Cr activity, transferrin and albumin. In all fractions the proteins were qualitatively characterised by iso electric focusing. The concentrations of transferrin and albumin were determined by nephelometry. The 51Cr distribution among the plasma proteins was similar for the three patients. The 51Cr activity was mainly bound to transferrin and, in the beginning of the incubation, in a lesser degree also to albumin. After 1-6 h a shift was observed of the 51Cr from albumin to an unidentified low molar mass complex (+/- 5000 Da). Two 51Cr species showed up in the subsequently drained dialysate, but they could not be identified.

Adult↗
PubMed1995

Determination of total arsenic in serum and packed cellsof patients with renal insufficiency.

In order to investigate the arsenic level in serum and packed cells of patients with renal insufficiency, total arsenic (As) concentrations were determined with hydride generation atomic absorption spectrometry (HGAAS) in serum (S) and packed cells (PC) of 31 non-dialyzed patients. The accuracy of the method was tested by the analysis of arsenic in 3 certified reference materials. Patients showed a three-fold increase of arsenic concentrations in serum and a two-fold increase of arsenic in packed cells compared with controls. Patients (n=10) with higher serum creatinine (>2.0 mg/dL), urea (>0.70 g/L) and urinary protein (mean+/-SD: 1.12+/-0.82 g/L) showed higher arsenic concentrations (5.8+/-3.3 microg/L in serum and 18.0+/-16.7 microg/kg in packed cells) compared with those with lower creatinine (<1.6 mg/dL), urea (<0.6 g/L) and urinary protein (mean+/-SD: 0.27+/-0.82 g/L) (n=16, serum arsenic 1.2+/-1.2 microg/L, packed cells arsenic 2.6+/-1.9 microg/kg). The significant differences (both p < 0.001) in S and PC-arsenic levels of patients in group I and II implies a relationship between the arsenic level and the degree of chronic renal insufficiency.

Journal Article↗
PubMed1995

Br, Rb, Zn, Fe, Se and K in blood of colorectal patients by INAA and PIXE.

A preliminary study was conducted on blood samples and blood fractions of 11 colorectal patients and 10 healthy subjects (controls) in Belgium, in order to determine the concentration of some vital trace elements. Two non destructive analytical methods were used for the determination: INAA and PIXE. The agreement between PIXE and INAA was within about +/- 10% for plasma, but for Rb, Se and Fe in whole blood and red cells a difference of +/- 20% was noted; part of the discrepancy may be due to self absorption problems in PIXE, and for Rb, spectral interferences also may have contributed. The precision of the INAA method for the elements studied was found to be +/- 3% for whole blood and red cells and +/- 5% for plasma; the accuracy for Br, Rb and Zn was better than +/- 10% and +/- 17% for Se. The ratios of the concentrations in whole blood to red cells and whole blood to plasma were not significantly different for normals and cancer cases and, therefore, in future studies analysis of whole blood only may be sufficient. The mean values for Br, Rb, Br/Rb ratio, K, Fe and Se were significantly lower for cancer cases than for healthy individuals, and this might be applicable as an additional parameter for differentiating normals from malignant cases.

Aged↗
PubMed1994

Trace element reference values in tissues from inhabitants of the European Community. VII. Review of trace elements in blood, serum and urine of the Belgian population and critical evaluation of their possible use as reference values.

The availability of accurate trace element reference values in human tissues represents an important indicator to the health status of the general population and occupational groups exposed to trace elements. The EURO TERVIHT project (Trace Element Reference Values In Human Tissues) aims to establish and compare trace element reference values in tissues from inhabitants of the European Community as baseline values for clinical/toxicological assessment studies (Sabbioni et al., 1992a,b). In this context one of the first steps considered is the critical evaluation (state of the art) of existing literature on trace element reference values in blood, serum and urine in the general population of each EC country. This paper reviews the Belgian situation.

Adolescent↗
PubMed1994

Use of 191Pt radiotracer for the development of enrichment procedures to detect natural levels of platinum in biological and environmental materials.

The 191Pt-radiotracer is a powerful tool to develop separation and preconcentration methods for Pt. The radiotracer was produced either through 190Pt (n, gamma) 191Pt reaction on Pt enriched in 190Pt, or through 191Ir (p,n) 191Pt reaction on natural Ir, followed by Pt/Ir separation. The solvent extraction behavior of 191Pt(IV) from HCl with tributylphosphate, rubeanic acid in tributylphosphate and thenoyltrifluoroacetone in n-butylalcohol/acetophenone, followed by back-extraction with 2 mol/L NH4OH was studied. The overall recovery from a biological matrix is up to 80%. Trace amounts of 191Pt were also preconcentrated as bis-(carboxymethyl) dithiocarbamate chelates on an XAD-4 microcolumn and eluted with EtOH/1 mol/L HNO3. More than 80% is recovered in 2 mL or about 70% in 300 microL.

Chromatography, Ion Exchange↗
PubMed1993

More than tenfold increase of arsenic in serum and packed cells of chronic hemodialysis patients.

Arsenic concentrations were determined in serum and packed cells of 7 chronic hemodialysis patients, in fresh dialysate and in a heparin solution. The analytical technique was radiochemical neutron activation analysis. The accuracy of the method was tested by the analysis of As in certified reference materials. Patients showed elevated serum and packed cell arsenic concentrations compared with controls (serum, range: 2.3-79.8 ng As/ml, median: 11.5 ng As/ml; versus range: 0.132-4.783 ng As/ml, median: 0.38 ng As/ml; packed cells, range: 2.1-68.4 ng As/g, median: 9.5 ng As/g; versus range: 0.51-14.44 ng As/g, median: 3.17 ng As/g). Arsenic concentrations remained unaltered, before versus after a single hemodialysis treatment. The arsenic contents of serum and packed cells were significantly correlated (n = 7, r = 0.96, p < 0.05). No arsenic could be detected in the heparin solution or in the dialysate.

Aged↗
PubMed1993

Recommendations of the International Union of Pure and Applied Chemistry concerning analytical quality criteria in the biological monitoring of toxic metals.

A working party of the Commission of Toxicology of the International Union of Pure and Applied Chemistry has been set up to establish criteria to ensure analytical quality in the biological monitoring of toxic metals. Although the project has not yet been completed, some useful guidelines have been produced. They pertain to the description of the subject (so as to allow classification into a given "reference group"), the collection, storage and sampling of body fluids for trace-element determinations, and criteria to ensure the application of the correct analytical procedure, together with a quality-assurance protocol. It was agreed that a dedicated sampling protocol is required for each trace element in a particular matrix. Although it is impossible to specify this protocol together with all subsequent procedures in precise detail, the members of the working party have laid down general rules to be followed. This paper summarizes what has been achieved to date.

Environmental Monitoring↗
PubMed1992

Distribution, accumulation and depuration of administered lead in adult honeybees.

In this study the Pb concentration in honeybees was determined by graphite furnace AAS after peroral administration of PbCl2. The Pb concentration, expressed on a dry weight base was determined in relation to the distribution over the body, the accumulation time, the clearance and the exposure dose. Pb is concentrated in the digestive system with the midgut accounting for 67% and the rectum for 27% of the accumulated metal. The barrier function of this system is thus corroborated in honeybees. Pb accumulation happens slowly in young bees which feed mainly on pollen; once they switch from pollen to nectar there is a sharp rise in their Pb content. After the 26th day a limit of tissue accumulation seems to be reached. Pb accumulation is equally efficient when the contamination starts at a forager age. Pb clearance is slower than expected; after 12 days only one third of the initial lead burden has been cleared. The Pb concentration in the animals increases significantly with the Pb concentration in the sugar syrup which they are fed, except at the highest dose of 50 mg/l. The possible use of honeybees as biomonitors for Pb pollution seems promising from these results.

Aging↗
PubMed1992

Five years of sentinel surveillance of acute respiratory infections (1985-1990): the benefits of an influenza early warning system.

For the last five years, the Brussels Institute of Hygiene and Epidemiology has been involved in the surveillance of acute respiratory infections (ARI). The four indicators used (number of encounters of ARI by GP's/100 encounters, virus isolations, absenteeism and mortality) are discussed. A regression procedure is applied to the data collected by a sentinel network of general practitioners (GP's). This procedure permits the baseline to be visualized and an epidemic threshold to be determined in order to recognize early an influenza outbreak. The traditional use of flu-like illnesses as an indicator might be improved by the addition of non-specific ARI which are more precocious, especially in children. The criteria for an accurate definition of an influenza epidemic are discussed. The same mathematical model can be used for the analysis of mortality linked with an outbreak. It shows that the last epidemic in the winter 1989-1990 was responsible for about 4900 deaths directly or indirectly related to influenza.

Absenteeism↗
PubMed1992

Use of radiochemical methods as tools for speciation purposes in environmental and biological sciences.

Chemical speciation for a few elements can be facilitated to a great extent by incorporating a suitable radioisotope into the system and measuring the radiation of the isolated species. This radiospiking can be applied to in vitro and in vivo labelled experiments. Radionuclides are, however, also present as an anthropogenic contaminant from various nuclear fission activities. The radiotracer should be added under such conditions that it behaves in exactly the same way as the isotopes it represents. It should possess an adequate radioactive half-life, and preferably be a gamma-emitter because of the ease of detection. Radiotracer labelling is now widely used to study speciation problems of many essential and toxic elements in body fluids and tissues. It can be used to trace the different locations where the element is metabolized and stored, and subsequently to detect the element in the isolated biocomponents. The determination of the location of a radiotracer in a cell by autoradiography proved to be impractical because of the lack of resolution. Radiochemistry is similarly very useful for investigating particular aspects of the speciation of heavy metals as they occur in the ecosystem, and to follow the fate and effects of fission nuclides in the environment as they are carried around by the water and air masses. However, in certain circumstances the behaviour of fission products appears to be different from that of their stable analogues. For the actinides they simply do not exist. Radiochemical methods are a major tool for identifying and quantifying the nuclides in the different species.

Animals↗
PubMed1992

The effect of adding Br or Zn supplements to the dialysate on the concentrations of Br and Zn in the blood of hemodialysed patients.

The effect of adding Br or Zn supplementation to the dialysate on the concentrations of Br and Zn in the blood of hemodialysed patients, is investigated. Patients with end-stage renal failure on hemodialysis show an abnormal trace element pattern. Our patients showed lowered serum Br and Zn concentrations. Four patients were subjected to dialysates with varying Br content. The impact on their serum and packed cells concentrations was evaluated. The supplementation resulted in an increase in the concentrations in serum and in packed cells. The Br concentration in serum and packed cells closely followed the dialysate content. In order to restore the Zn concentration to the normal level a ZnCl2 solution was added to the dialysate of 4 other patients. Zn accumulated in the patient as a consequence of its diffusion against the concentration gradient.

Bromine↗