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Biomedical subjects

F Vertongen

Publications and source records attributed to F Vertongen.

At least 55 records · Page 3Linked to original sources
PubMed1988

Selenium supplementation in healthy Belgian adults: response in platelet glutathione peroxidase activity and other blood indices.

Selenium status was explored by investigating effects of a 60-d Se supplementation with DL-selenomethionine (100 micrograms Se/d) in a group of 10 adults (plasma Se levels, 0.76-1.33 mumol/L). Plasma, erythrocyte, and urinary Se and activities of glutathione peroxidase (GSH Px) in plasma, erythrocytes, and platelets were measured before intervention and after 5, 15, 30, 45, and 60 d. A placebo was given to six adults. Plasma and urinary Se were the most sensitive indices to Se exposure. Se in plasma increased steadily during the course of the study whereas urinary Se reached a plateau between 30 and 60 d. By contrast erythrocyte Se did only change after 45 d. Enzyme in plasma and erythrocytes did not respond whereas platelet GSH Px did. The plateau of activity that was observed after 15 d for plasma Se in the range 1.40-1.50 mumol/L could mean that the Se status is insufficient for an optimal function of GSH Px and implies that dietary intake in Belgium (less than 50-60 micrograms Se/d) is not adequate.

Adult↗
PubMed1988

[Sequential development of vitamin D metabolites under isoniazid and rifampicin therapy].

A sequential study of 25-hydroxy vitamin D (25-OH-D), 1.25 dihydroxy vitamin D [1.25 (OH)2-D], PTH, alkaline phosphatase and gammaglutamyl transpeptidase (gamma GT) was undertaken in a series of 46 children with asymptomatic tuberculosis treated by isoniazid (INH) alone or associated with rifampin (RMP). These parameters were measured before treatment, 1 month, 3 months after the onset and at the end of treatment (6 months). In order to reduce the influence of the time of the year on the 25-OH-D levels, 22 patients were selected for whom the whole treatment took place between October and May of the following year. In this group, 13 children were treated by INH and RMP, 9 by INH alone. A statistically significant decrease in 25-OH-D levels could be demonstrated after 3 months of treatment in 13 patients under INH and RMP as well as a significant increase in alkaline phosphatase and gamma GT levels. In 9 patients given INH alone, 1.25 (OH)2-D levels decreased after 3 months without significant changes in 25-OH-D, alkaline phosphatase or gamma GT levels. These results emphasize the need for regular biochemical supervision, even if no sign of rickets is observed in these patients.

Adolescent↗
PubMed1987

Selenium status in relation to clinical variables and corticosteroid treatment in rheumatoid arthritis.

Plasma selenium levels, erythrocyte selenium levels and activity of the selenoenzyme glutathione peroxidase in erythrocytes were determined in patients with rheumatoid arthritis (RA) and acute inflammatory arthritis. Results were compared with those from age and sex matched controls. These variables were not statistically different from controls in patients with inflammatory arthritis and in patients with RA not treated with corticosteroids. No correlation was found in RA between plasma selenium biological variables of inflammation and most clinical indices of disease severity. Therefore, acute or chronic inflammation was not the main factor that accounted for low plasma selenium levels in RA. Corticosteroid treatment, particularly at high doses (20-60 mg prednisolone/day), was significantly related to the depressed plasma selenium levels of some patients with RA. The mechanisms underlying this modification remain poorly understood.

Acute Disease↗
PubMed1986

Deoxythymidine and deoxycytidine incorporation into DNA in B leukemic cells.

Measurements of radioactive DNA after incubation of normal and B leukemic peripheral mononuclear cells, from c-ALL and CLL with labeled deoxythymidine (dTh) and deoxycytidine (dCt) showed that for dTh, incorporation into DNA was similar for normal and c-ALL cells but lower in B-CLL cells and that for dCt, incorporation was highest in c-ALL and lowest in CLL cells. These results contrast with those of dTh and dCt kinase activities; the former has been previously found elevated in c-ALL cells, and the latter is found, in the present study, similar in the three groups tested.

B-Lymphocytes↗
PubMed1986

Influence of the degree of metabolic control on physical fitness in type I diabetic adolescents.

Seventeen type I male diabetic adolescents and 17 control subjects matched for age, height, and weight were submitted to maximal exercise on a bicycle ergometer. The diabetic subjects were divided into two groups according to their degree of metabolic control using total glycosylated hemoglobin (HbA1): group 1, diabetics with HbA1 less than 8.5% (n = 9) and group 2, diabetics with HbA1 greater than 8.5% (n = 8). Oxygen uptake, pulmonary ventilation, and heart rate were recorded at rest and at maximal load. Glucose, lactate, and free fatty acids were determined in blood before and after exercise. Maximal work load and oxygen uptake were significantly lower in the two diabetic groups than in the healthy controls. An inverse relationship was observed between HbA1 concentration and the maximal work load (r = -0.63; P less than 0.01). It can be concluded that diabetic adolescents should obtain the best possible degree of metabolic control to improve their performances.

Adolescent↗
PubMed1986

Generalized unresponsiveness to mineralocorticoid hormones: familial recessive pseudohypoaldosteronism due to aldosterone-receptor deficiency.

The present report describes two sibs--born from consanguineous parents--presenting with severe salt wasting. Generalized pseudohypoaldosteronism (PHA) was diagnosed on the basis of markedly elevated sodium concentration in urine (84 & 63 mmol/L respectively), sweat (181 & 196), saliva (- & 120) and stool (- & 189), hyponatremia (112 & 132) and hyperkalemia (10.7 & 7.3) in the presence of increased plasma aldosterone (greater than 8.5 & 5.4 ng/ml), plasma renin activity (40 & 18.9 ng/ml/hr) and urinary aldosterone (greater than 32 & 11.6 micrograms/day). Both parents investigated under basal conditions (sodium ad libitum) and under sodium restricted diet appeared to be normal. Aldosterone binding studies performed on mononuclear leukocytes showed no type I receptors in the investigated child whereas low amounts were found in both parents (90 sites/cell and 63 sites/cell in the mother and the father, respectively). Isolated renal unresponsiveness to mineralocorticoid hormones is thought to be an autosomal dominant inherited disease. In contrast, the results obtained in these two new cases of generalized PHA, as well as the fact that four of five yet reported cases were born from consanguineous parents, suggest an autosomal recessive mode of inheritance for generalized PHA.

Aldosterone↗
PubMed1985

Selenium deficiency.

Selenium is undoubtedly an essential trace element: its involvement in GPx structure, the presence of deleterious effects of selenium deficiency in animals, and the recognition of deficiency states in man attest to its importance. However, if the consequences of selenium deficiency in man are now widely recognized, the mechanisms underlying these conditions are poorly understood. The definition of the exact role of selenium in human homeostasis has been hampered by the lack of a sensitive parameter, usable in routine investigation, to assess selenium status. Measurements of plasma and urinary levels, although useful in clinical practice, are inadequate indicators. The only true evidence of selenium deficiency lies in a positive response to selenium therapy. Deficiency states have been demonstrated for inhabitants of regions where selenium supply is limited, in protein-energy malnutrition, and in patients maintained on total parenteral nutrition without selenium supplementation. The benefit of selenium supplementation, together with other antioxidant drugs, in non-deficient subjects is still a matter of debate; its protective effect in neoplastic, cardiovascular and neurological degenerative diseases is not yet proven.

Animals↗
PubMed1985

Purine enzyme levels in rheumatoid arthritis.

We studied purine metabolism in rheumatoid arthritis (RA), adenosine deaminase (ADA), 5'-nucleotidase (5'NU) and purine nucleoside phosphorylase (PNP) activities by measuring the circulating mononuclear cells of patients with RA and healthy controls. Patients had significantly lower levels of ADA and 5'NU but not of PNP than controls. The decreases could not be related to age, antiinflammatory therapy, decreased percentages of T cells or imbalance between major T cells subsets. Differences in cell maturation or traffic could account for our observation. Alternatively, abnormalities of purine metabolism are not definitely excluded in RA if the lower enzyme activity is not sufficient to perform the metabolic steps.

5'-Nucleotidase↗
PubMed1985

Evolution of serum amylase, lipase and immunoreactive trypsin during pancreatitis attacks.

The characteristics of the blood curves of alpha-amylase (SA), pancreatic lipase (SL) and immunoreactive trypsin (SIT) have been analyzed in a series of patients daily explored throughout the evolution of pancreatitis attacks; urines were also collected to estimate the amylase-creatinine clearance ratio (ACCR). The following results were obtained. a). The 3 enzymes profiles ran roughly parallel during an acute attack. b). SL rose far higher than SA at the onset of the attack but its decay displayed a shorter half-life than the latter; these features resulted in an absence of systematic difference between their times of return to normal levels at the end of the attack. c). SIT more closely correlated with SL than with SA. d). In common hospital practice, simultaneous SA and SL determinations were proving a more reliable help to diagnose pancreatitis attack than ACCR.

Acute Disease↗
PubMed1985

Erythrocyte vitamin E is oxidized at a lower peroxide concentration in neonates than in adults.

Erythrocytes of neonates and adults were incubated with increasing concentrations of H2O2 in the presence of a catalase inhibitor and in the absence of glucose; the pattern of oxidation of vitamin E was analyzed in relationship to that of glutathione, hemoglobin, and polyunsaturated fatty acids (PUFA), and in relationship to hemolysis. The changes of these various parameters were analyzed in function of H2O2 concentration and in relation to incubation time, and were compared in erythrocytes from neonates and adults. In the absence of H2O2, erythrocyte glutathione and tocopherol levels were similar in neonates and adults, despite fourfold lower serum vitamin E level in neonates; alpha-tocopherolquinone, methemoglobin, and malonyldialdehyde (MDA) were not detectable. At 0.375 mmol/L of H2O2, glutathione was completely oxidized. Erythrocyte alpha-tocopherol remained unchanged up to 0.75 mmol/L of H2O2, then decreased linearly, with increasing H2O2 concentrations to 10% of its initial value at 1.5 mmol/L of H2O2 in erythrocytes from neonates, whereas those from adults required 2.0 mmol/L of H2O2 (P less than .05) for the same level of oxidation. The formation of alpha-tocopherolquinone appeared inversely related to the decrease of alpha-tocopherol. The incubation time did not influence the level of vitamin E oxidation. MDA was generated autocatalytically and resulted in hemolysis at 1.5 mmol/L of H2O2 in erythrocytes from neonates and at 3.5 mmol/L of H2O2 in erythrocytes from adults (P less than .001). After four hours of incubation, MDA reached a plateau at a greater level (365 +/- 46 nmol/L) in cells of neonates than in those of adults (208 +/- 37 nmol/L/mL) (P less than .001). Hemoglobin was oxidized in the same pattern in erythrocytes of neonates and adults, and 90% of it was oxidized at 0.625 mmol/L of H2O2. In conclusion, in the experimental conditions used, oxidation of glutathione precedes that of vitamin E, and tocopherol is the last antioxidant to be consumed before the autocatalytic generation of MDA. Differences in the pattern of vitamin E oxidation, MDA generation, and hemolysis in erythrocytes from neonates and adults may be due to a lower erythrocyte vitamin E-PUFA ratio in neonates.

Adult↗