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Biomedical subjects

H Roels

Publications and source records attributed to H Roels.

At least 127 records · Page 7Linked to original sources
PubMed1983

Development of a quantitative test for hand tremor measurement. Study of factors influencing the response in a control population.

The frequency spectrum of hand tremor amplitude was investigated in a group of 15 control subjects under four different conditions (rest position, wrist loading with 2 kg, pointer directed to a target, and wrist loading with 2 kg, pointer directed to a target, and wrist loading plus pointer). The series of four tremor recordings was repeated on three different days. The hand tremor pattern was recorded using an accelerometer connected to a tape recorder through a precision sound level meter. The tremor signals were subsequently analyzed with a real time spectrum analyzer. Different parameters (peak frequencies, acceleration amplitudes, moments, displacements, and velocities) have been determined and their variability has been characterized. The method described for hand tremor recording is suitable for field application.

Adult↗
PubMed1982

The possible role of direct ingestion on the overall absorption of cadmium or arsenic in workers exposed to CdO or As2O3 dust.

Six volunteers (two office and four cadmium (Cd)-exposed workers, all nonsmokers) from an electric condenser factory participated in a study involving the measurement of cadmium in air and in dust, the evaluation of hand and mouth contamination by cadmium, and the determination of fecal cadmium. The mean levels of total airborne cadmium measured with static and personal samplers were for the exposed workers 9.5 and 16.7 microgram/m3, respectively, and for the office workers 0.3 and 0.5 microgram/m3, respectively. In the office workers, hand contamination by Cd hardly changes over the workday (less than 10 microgram/hand), whereas in the exposed workers important hand contamination by Cd was observed (up to 1,200 microgram/hand during the workday and up to 300 microgram/hand before lunch or before leaving the factory). Mouth contamination by Cd is rather similar in both groups on Monday morning, but increases 20- to 50-fold on Friday afternoon in the Cd workers against a slight increase for the office workers. The concentration of Cd in the feces was not much different between Sunday and Friday in the office workers, whereas in the exposed workers it was higher on Friday than on Sunday. There is suggestive evidence from a comparative study of fecal cadmium in two Cd-exposed volunteers who carried out their jobs with and without gloves that direct cadmium intake from hand contamination may contribute to the overall Cd absorption. A limited study in a glassware factory (As2O3 exposure) involving the measurement of total airborne arsenic, the determination of urinary arsenic, and the evaluation of hand and mouth contamination by arsenic before and after the workshift suggests that the high urinary arsenic levels (300 microgram/g creatinine) are likely to be more related to an increased oral intake from contaminated hands than to an increased absorption from the lungs.

Air↗
PubMed1982

Comparison of renal function and psychomotor performance in workers exposed to elemental mercury.

Renal function and psychomotor performance (eye-hand coordination, arm-hand steadiness) of a group of 43 workers exposed to mercury vapor were examined. Their mean age an average duration of exposure to mercury were 38 and 5 years, respectively. The results were compared with those in a matched group of 47 control workers. Increased proteinuria and albuminuria were found slightly more prevalent in the Hg-exposed group than in the control workers. These results are in agreement with those found during a previous study carrier out in another group of workers also exposed to elemental mercury (Buchet et al. 1980). The scores of the psychomotor tests were less satisfactory in the Hg workers than in the control workers, the arm-hand steadiness test being more discriminative than the eye-hand coordination test. Preclinical changes in psychomotor function can be detected independently of the presence of signs of renal dysfunction. No clear-cut relationships were found between the prevalence of abnormal psychomotor scores and the level of mercury in blood (HgB) or in urine (HgU). Increased prevalences of abnormal psychomotor scores seem however to occur for HgB between 1 and 2 micrograms/100 and for HgU between 50 and 100 micrograms/g creatinine. Therefore, a biologic threshold limit value of 50 micrograms/g creatinine in proposed for urinary mercury to prevent the development of preclinical effects on the central nervous system. A similar critical HgU level based on renal dysfunction prevalences has been suggested in a previous study.

Adult↗
PubMed1982

Evolution of cadmium-induced renal dysfunction in workers removed from exposure.

A retrospective examination of the medical records gathered during several surveys carried out among cadmium workers has permitted the identification of a group of 19 workers who had been examined before and after removal from cadmium exposure. All the workers had been exposed for more than 15 a (range 15.6-41.7 a). Their last examination took place from 0.3 to 7.9 a after the date of removal from cadmium exposure. At that time, all the workers exhibited sign(s) of cadmium-induced renal dysfunction. Comparison of the renal function parameters (serum creatinine, total proteinuria, aminoaciduria, albuminuria, beta 2-microglobulinuria, and the urinary excretion of retinol-binding protein) before and after the cessation of exposure indicated that cadmium-induced renal lesions, albeit of slow progression, are not reversible when exposure ceases.

Adult↗
PubMed1982

[Cadmium toxicity: summary of personal studies].

Occupational and environmental exposure to cadmium leads to a progressive and almost irreversible accumulation of the metal in the body. The epidemiological and experimental studies carried out by the authors allow them to draw the following conclusions: 1) the kidney is usually the critical organ i.e. the organ exhibiting the first signs of adverse effects following long term moderate exposure to cadmium by inhalation or by ingestion. 2) Cadmium interferes not only with the tubular reabsorption process(es) for low molecular weight proteins (e.g. beta 2 . microglobulin, retinol binding protein) but also with the glomerular or tubular mechanism determining the excretion of high molecular weight proteins (e.g. albumin, transferrin). Both types of proteinuria may occur independently. 3) The renal functional disturbances induced by cadmium and compatible not only with a tubular dysfunction but also a glomerular dysfunction. 4) The early detection of renal disturbances induced by cadmium should not rely only on the determination of total proteinuria but necessitates the analysis in urine of at least one low molecular weight protein (beta 2-microglobulin or retinol binding protein) and one high molecular weight protein (albumin). 5) Before the occurrence of renal dysfunction and providing the intensity of exposure to cadmium is moderate, urinary cadmium reflects mainly the body burden whereas blood cadmium reflects mainly the last few months exposure. 6) In adult male workers occupationally exposed to cadmium, the critical concentration of cadmium in the renal cortex is in the order of 200 ppm. The corresponding critical urinary level is approximately 10 micrograms/g creatinine. The critical level of cadmium in the renal cortex is not reached if the exposure is kept at a level where cadmium in blood does no exceed 1 microgram/100 ml. 7) Comparison of literature data on current exposure of the general population to cadmium and the critical exposure level indicates that some groups of the general population absorb daily amounts of cadmium closed to the critical level. 8) The critical biological levels indicated under (6) do not necessarily prevent an exacerbation of the age-related decline in renal function. 9) A preliminary study performed in Belgium suggests that cadmium might play a role in the increased mortality by renal diseases in a population living in an area polluted by cadmium. More detailed studies are necessary to confirm this hypothesis.

Cadmium↗
PubMed1982

[Familial erythrophagocytic lymphohistiocytosis. Report of five cases with cytophotometric study of nuclear DNA (author's transl)].

The authors report five cases of familial erythrophagocytic lymphohistiocytosis (F.E.L.H.). Two patients are brothers. One case is associated with a striking extramedullary hematopoiesis. A cytophotometric study of nuclear DNA in the histiocytes was performed in all cases. The histiocytes are diploid and there is no aneuploidy. These findings allow the authors to exclude the hypothesis of the tumoral nature of F.E.L.H. The data collected from the literature about the familial incidence of F.E.L.H. militate for an autosomal recessive transmission. The extramedullary hematopoiesis, which has not yet been reported in association with F.E.L.H., is probably due to the intense lymphohistiocytic infiltration of the bone marrow.

Child, Preschool↗
PubMed1981

Comparison of the urinary excretion of arsenic metabolites after a single oral dose of sodium arsenite, monomethylarsonate, or dimethylarsinate in man.

The urinary elimination of the metabolites of arsenic has been followed up as a function of time in volunteers who ingested a single oral dose of arsenic (500 microgram As) either as sodium arsenite (Asi), monomethylarsonate (MMA), or cacodylate (DMA). The excretion rate increased in the order Asi less than DMA less than MMA. After 4 days, the amount of arsenic excreted in urine represents 46, 78, and 75% of the ingested dose in the case of Asi, MMA and DMA, respectively. With regard to the in vivo biotransformations, it is concluded that DMA is excreted unchanged; MMA is slightly (13%) methylated into DMA while roughly 75% of the arsenic excreted after ingestion of Asi is methylated arsenic (about 1/3 as MMA and about 2/3 as DMA).

Adult↗
PubMed1981

Assessment of renal function of workers simultaneously exposed to inorganic lead and cadmium.

The renal function of a group of workers (n = 62) exposed simultaneously to lead and to cadmium has been examined. The results were compared with those obtained in a earlier study of three groups of workers - one exposed to lead only, one exposed to cadmium only and one not exposed to either of these metals (control group). The results obtained in the earlier study have been published previously. No interaction between lead and cadmium is evidenced. The signs of renal dysfunction found in the group exposed simultaneously to lead and to cadmium can be ascribed to cadmium only. The results of this study have confirmed the authors' previous observations, that is, a moderate exposure to lead (plumbemia less than 62 micrograms/100 ml and average duration of exposure = 13.2 years) does not seem to influence renal function; in adult male workers the critical levels of cadmium in blood and in urine are 1 microgram/100 ml whole blood and 10 micrograms/g creatinine, respectively; the renal dysfunction induced by cadmium is both glomerular and tubular.

Adult↗
PubMed1980

Relationship between exposure to heavy metals and prevalence of renal dysfunction.

Total proteinuria (biuret method) and the urinary excretion of specific proteins (albumin, transferrin, orosomucoid and IgG measured by an automated immunoprecipitin reaction and beta 2-microglobulin determined by radioimmunoassay) have been assessed in four groups of workers: a control group (n = 88) and a group exposed to cadmium (n = 148), mercury vapour (n = 63) and lead (n = 25) respectively. The results demonstrate that a moderate exposure to lead (lead concentration in blood < 62 micrograms/100 ml) does not change the prevalence of renal dysfunction, whereas mercury vapour exposure increases the prevalence of subjects with excessive excretion of albumin (> 12 mg/g creatinine), orosomucoid (> 4.35 mg/g creat.) and IgG (> 3.5 mg/g creat.). Besides an increased excretion of beta 2-microglobulin (> 200 micrograms/g creat.) workers exposed to cadmium excrete a greater amount of high molecular weight proteins. An increased excretion of urinary proteins occurs when mercury and cadmium level in urine exceeds 50 and 10 micrograms/g creatinine respectively.

Cadmium Poisoning↗
PubMed1980

Dumb-bell sarcoma of the foramen jugulare with syringomyelia. A radio-induced tumour?

The clinicopathological findings of a 50-year-old man, who developed cervicothoracic syringomyelia at the age of 25 are presented. He was given radiation therapy at the age of 33. At the age of 57 he developed a foramen jugulare syndrome on the left, caused by a low grade leiomyosarcoma. Etiologically, the most attractive hypothesis appears to be that the tumour was induced by radiation therapy administered 24 years previously.

Adult↗
PubMed1980

Cytophotometric investigation of the Feulgen-DNA content of cell nuclei of fibrous histiocytomas.

The cytophotometric determination of the Feulgen-DNA content of cell nuclei was performed on 72 fibrous histiocytomas. From the histograms, three variants of this neoplasm could be delineated and there was a fairly good correlation between the type of histogram and prognosis. With the exception of the benign dermal fibrous histiocytomas there was no correlation with the histological sub-types.

Cell Nucleus↗