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Biomedical subjects

F Vertongen

Publications and source records attributed to F Vertongen.

At least 37 records · Page 2Linked to original sources
PubMed1998

Globin chains analysis: improved resolution by electrophoresis in urea-acetic acid-Triton X-100.

To improve the resolution and rapidity of globin chains separation, we have modified the basic technique of globin chain electrophoresis in urea-acetic acid-Triton X-100. Haemolysates from anticoagulated cord or adult blood samples were submitted to urea-acetic acid-Triton X-100 polyacrylamide gel electrophoresis using a 15% polyacrylamide gel cast in a mini slab cell which allows a rapid analysis of globin chains samples. After staining proteins with Coomassie brilliant blue R-250, the relative amounts of globin chains were determined by scanning. This new procedure has allowed us to obtain a better separation of the normal and abnormal globin chains than described previously. All the normal globin chains, i.e. A gamma, G gamma, delta, beta and alpha, are well separated by this modified technique. Semi-quantification of the G gamma/A gamma ratio has been performed. This simple and rapid method is also suitable for the global identification of the globin chain involved in the most common abnormal haemoglobin variants, except beta-S.

Acetic Acid↗
PubMed1998

[Hereditary spherocytosis: one year study of erythrocyte membrane proteins].

Hereditary spherocytosis (HS) is a congenital hemolytic anemia which affects one person out of 5000 in Northern Europe. HS is caused by defects of the red cell membrane proteins involving mainly ankyrin or band 3, and less frequently, protein 4.2 or spectrin. The reduction of red cell osmotic resistance and the recognition of spherocytes on the peripheral blood smear are the primary laboratory tests necessary to evocate a diagnosis of hereditary spherocytosis. Analysis of the red cell membrane proteins using polyacrylamide gel electrophoresis is used to quantify individual proteins and to identify the protein defect related to a diagnosis of HS. Samples from 47 patients and 25 controls were studied by electrophoresis of the red cell membrane proteins. Protein deficiencies related to HS were demonstrated for 21 patients. In 4 other cases, abnormalities of membrane proteins unrelated to HS were also demonstrated. Electrophoresis of the red cell membrane proteins allows the identification of the protein deficiency related to HS and thus confirms the diagnosis of HS, but also points to the underlying molecular defect, the inheritance pattern and the clinical aspects of the disease.

Adolescent↗
PubMed1997

Structural and functional studies of hemoglobin Moabit (alpha 86(F7) Leu-->Arg.

An abnormal hemoglobin fraction was detected on high performance liquid chromatography profile performed for the measurement of glycated hemoglobin in a 55-year-old caucasian patient. The structural and functional studies were performed by standard techniques. Separation of hemoglobins by alkaline electrophoresis and by IEF revealed a slightly more rapid fraction than does Hb S. By acid electrophoresis, no abnormal Hb fraction could be observed. Separation of globin chains by electrophoresis demonstrated an alpha-chain variant and by chromatography, a fraction which eluted between beta and gamma globin chains. Tryptic digests and amino acid analysis have demonstrated a previously described substitution of Leu-->Arg alpha 86(F7).

Blood Protein Electrophoresis↗
PubMed1997

Urinary iodine excretion during normal pregnancy in healthy women living in the southwest of France: correlation with maternal thyroid parameters.

A prospective study was undertaken to evaluate urinary iodine excretion and changes of maternal thyroid function during pregnancy in healthy women living in the southwest of France. The cohort included a total of 347 pregnant women (mean age 28.0+/-0.5 years). Iodine concentration in a random urine sample and thyroid tests (free thyroxine [FT4], free triiodothyronine [FT3], thyrotropin (TSH), thyroxine-binding globulin [TBG], and thyroglobulin [Tg]) were measured at initial presentation (before 12 weeks of gestation), and during the ninth month of pregnancy. A thyroid ultrasound was performed 1 to 5 days after delivery in 246 mothers. Mean urinary iodine levels were low during the first trimester (6.9+/-0.4 microg/dL), as well as during the ninth month of pregnancy (8.6+/-0.6 microg/dL). During pregnancy, FT4 and T3 concentrations decreased (p < .001), and TSH and Tg concentrations increased (p < .001). Thyroid hypertrophy (thyroid volume greater than 18 mL) was present in 15.4% of women whose first trimester urinary iodine concentration was less than 5 microg/dL, but was present in only 3.5% of women whose urinary iodine concentration was greater than 10 microg/dL. A goiter (thyroid volume greater than 22 mL) was present in 11% of the mothers. In conclusion, this prospective study shows that urinary iodine excretion is low in pregnant women living in the southwest of France. This low iodine intake is associated with reduced circulating thyroid hormone levels and growth of the thyroid gland. These data point to the need of an increased iodine supply in these pregnant women to reduce the potential consequences of low iodine intake on maternal thyroid economy.

Adolescent↗
PubMed1997

Thyroid volume and urinary iodine in European schoolchildren: standardization of values for assessment of iodine deficiency.

Up to 1992, most European countries used to be moderately to severely iodine deficient. The present study aimed at evaluating possible changes in the status of iodine nutrition in 12 European countries during the past few years. Thyroid volume was measured by ultrasonography in 7599 schoolchildren aged 7-15 years in one to fifteen sites in The Netherlands. Belgium, Luxemburg, France, Germany, Austria, Italy, Poland, the Czech and Slovak Republics, Hungary and Romania. The concentrations of urinary iodine were measured in 5709 of them. A mobile unit (ThyroMobil van) equipped with a sonographic device and facilities for the collection of urine samples visited all sites in the 12 countries. All ultrasounds and all urinary iodine assays were performed by the same investigators. The status of iodine nutrition in schoolchildren has markedly improved in many European countries and is presently normal in The Netherlands, France and Slovakia. It remains unchanged in other countries such as Belgium. There is an inverse relationship between urinary iodine and thyroid volume in schoolchildren in Europe. Goiter occurs as soon as the urinary iodine is below a critical threshold of 10 micrograms/dl. Its prevalence is up to 10 to 40% in some remote European areas. This work produced updated recommendations for the normal volume of the thyroid measured by ultrasonography as a function of age, sex and body surface area in iodine-replete schoolchildren in Europe. This study proposes a method for a standardized evaluation of iodine nutrition on a continental basis, which could be used in other continents.

Adolescent↗
PubMed1997

[Neonatal screening for hemoglobinopathies in the Brussels region].

We realised this study in order to determine the frequency of abnormal haemoglobins and to appreciate the need for a neonatal screening for haemoglobinopathies in Brussels. Over a two year-period, 9575 cord blood samples were systematically screened. The study disclosed following results : 40% of newborns were from regions at risk for haemoglobinopathies and abnormal haemoglobins were present in 2.5% of the neonates tested. This frequency is similar to those reported elsewhere in North Europe. The most frequent abnormal haemoglobins were the Hb S, Bart's, C, D and E. Three cases of severe forms of sickle cell anaemia were identified. The frequency of abnormal haemoglobins and Hb S traits combined to the high rate of mixed marriages (16%) justifies the need for a universal screening for haemoglobinopathies in Brussels.

Belgium↗
PubMed1996

[Erythrocyte and plasma antioxidant activity in diabetes mellitus type I].

OBJECTIVES: Some biologic parameters involved in cell defence against oxygen radicals (plasmatic vitamins C and E, erythrocyte glutathione peroxidase, glutathione reductase and superoxide dismutase) were measured in single blood samples from 119 diabetic infants, adolescents and young adults. METHODS: Data were studied in relation to residual insulin secretion determined by C peptide, level of metabolic control appreciated by glycosylated haemoglobin, lipid abnormalities and subclinical complications (retinopathy, neuropathy and nephropathy). RESULTS: There was no change in antioxidant parameters with insulin secretion. Patients with poor glycaemic control and high plasma lipids had higher levels of plasma vitamin E. Patients with nephropathy had lower plasma vitamin C levels and those with neuropathy showed lower erythrocyte glutathione peroxidase activity. Plasma vitamin C concentrations and erythrocyte glutathione reductase activities were negatively correlated with the age of the patients and the duration of the disease. CONCLUSION: Higher transport capacity of vitamin E probably explains the elevated levels of vitamin E observed in patients with high lipid levels and long lasting illness. The lower levels of vitamin C in the presence of nephropathy may be due to an increased renal excretion of this vitamin. The reduction of glutathione peroxidase, glutathione reductase activities and vitamin C levels confirms the existence of an oxidative stress in type I diabetes.

Adolescent↗
PubMed1996

Severity of asthma is related to endotoxin in house dust.

In sensitized subjects, exposure to the mite allergen appears to be only one of several factors leading to asthma. We hypothesized that in association with allergen exposure, endotoxin, a proinflammatory agent present in house dust (HD), influences the severity of asthma. Using a cross-sectional study design, we investigated a group of 69 consecutive dust mite (HDM)-sensitized subjects defined as having rhinitis (n = 20) or asthma (n = 49); the latter were evaluated functionally and clinically by three different scores and by their need for daily medication. Concentrations of Dermatophagoides pteronyssinus p I allergen (Der p I) (by two-site monoclonal antibody enzyme-linked immunosorbent assay [ELISA]), guanine (by high-pressure liquid chromatography [HPLC]), and endotoxin (by modified Limulus. amebocyte lysate assay) were measured in HD collected in duplicate from the mattresses and floors in each subject's home. The concentrations of Der p I and of guanine in HD collected from mattresses were significantly higher in asthmatic subjects than in those with rhinitis (p < 0.05 and < 0.04, respectively). In subjects (n = 37) exposed to a high level of HDM allergen (i.e., Der p I > or = 10 micrograms/g HD and/or guanine > or = 0.10 mg/100 mg HD), the severity of asthma was unrelated to mite allergen concentration in HD. On the contrary, the severity of asthma was related to concomitant exposure to endotoxin in HD, since the concentration of HD endotoxin was significantly and inversely correlated with FEV1 (p < 0.05), FEV1/FVC (p < 0.02), daily need for oral (p < 0.01) and inhaled (p < 0.01) corticosteroids, daily need for beta 2 agonists (p < 0.001) and xanthines (p < 0.01), and clinical scores such as the modified Aas score (p < 0.01). In HDM-sensitized subjects exposed to a high level of allergen, the concentration of endotoxin measured in HD is an important determinant of asthma severity.

Adult↗
PubMed1996

Vitamin A deficiency and protein-energy malnutrition in a sample of pre-school age children in the Kivu Province in Zaire.

OBJECTIVE: To assess pre-school age children's vitamin A status in a population where protein-energy malnutrition is endemic and serum retinol binding protein and transtyretin concentrations are low. DESIGN: A cross-sectional study. SETTING: Health district of Katana, South-Kivu, Zaire. SUBJECTS: 415 pre-school age children. METHODS: Three methods were used to assess vitamin A status: ophtalmological examination, retinol serum concentration and Relative Dose Response (RDR) test. RESULTS: The only ophthalmological signs of vitamin A deficiency appeared in two cases of night blindness, which represents a prevalence of 0.7%. Deficient serum retinol concentration (< 0.35 mumol/l) was found in 19.7% of the whole study population and in 10.4% of non-infected children in good nutritional status. RDR test carried out on a reduced sample of 79 subjects was abnormal for 7.6% of the children but showed a low sensitivity when compared with serum retinol concentration. CONCLUSION: This survey suggests that in this population of the South-Kivu Province in Zaire, vitamin A deficiency co-exists with protein-energy malnutrition and is a public health problem even with non-malnourished and non-infected children.

Anthropometry↗
PubMed1995

Effects of bedtime administration of zolpidem on circadian and sleep-related hormonal profiles in normal women.

Short-acting benzodiazepine hypnotics may phase-shift circadian rhythms and improve adaptation of sleep patterns to abrupt time shifts, depending on the timing of administration. The aim of the present study was to determine whether bedtime administration of zolpidem, a non-benzodiazepine hypnotic, causes alterations in circadian rhythmicity or in the normal interactions between sleep and hormones. Eight normal women (aged 21-33 years) each participated in a baseline study and a study with zolpidem administration. On each occasion, blood samples were obtained at 20-minute intervals for 25 hours, starting at 1000 hours. Zolpidem (10 mg) was given orally at 2245 hours. Zolpidem administration was associated with an increase in stages III + IV sleep. Cortisol, melatonin, thyrotropin and growth hormone profiles were similar in both experimental conditions. In contrast, though remaining in the normal range, the nocturnal elevation of prolactin was enhanced two-fold in all subjects after zolpidem during early sleep, and prolactin levels were still 50% higher than baseline in late sleep. Morning levels were similar in both studies. In conclusion, bedtime administration of 10 mg zolpidem, a standard clinical dosage, systematically induces a transient moderate hyperprolactinemia, but does not alter other sleep-related hormonal secretions or endocrine markers of circadian rhythmicity.

Adult↗
PubMed1995

Transplanted sickle-cell disease patients with autologous bone marrow recovery after graft failure develop increased levels of fetal haemoglobin which corrects disease severity.

Bone marrow transplantation (BMT) is the only curative therapy for sickle-cell disease (SCD), but is not devoid of failure risk. Nine patients with severe SCD were grafted in our institution between 1988 and 1993. Six patients successfully engrafted, but three failed to engraft and had delayed autologous recovery. All patients had, prior to BMT, low levels of fetal haemoglobin (HbF < or = 3.5%). No change in HbF occurred in successfully grafted patients. In the three patients with graft failure HbF increased and remained persistently present at a high level (> or = 22%) 14 months, 16 months and 39 months post BMT, although two of the three patients were homozygous for either the Benin or the Central African Republic haplotype, a characteristic associated with low HbF level. Of interest, these three previously severely affected patients remain free of vaso-occlusive events. The mechanism responsible for the expression of high levels of HbF in our three patients with graft failure is not understood, but it protects them from the recurrence of severe vaso-occlusive crises.

Anemia, Sickle Cell↗
PubMed1992

Erythrocyte metabolic alterations in type I diabetes: relationship to metabolic control.

Erythrocytes from young type I diabetic patients (n = 11), incubated in their plasma in anaerobic conditions, exhibited higher glucose consumption than cells from controls (n = 11). This increased metabolic activity is believed to reflect erythrocyte alterations dependent on the degree of metabolic control, as glucose consumption was significantly correlated to glycosylated haemoglobin (HbA1) and to glucose levels (P < 0.05 and P < 0.01 respectively). Red cell hexokinase (HK) and pyruvate kinase (PK) activities were similar in both groups whereas phosphofructokinase (PFK) activity was slightly higher in patients' cells (P < 0.05). No difference was found between patients and controls for red cell ATP and 2.3 diphosphoglycerate (2.3 DPG) levels. However, the concentrations of these glycolytic products seem also closely related to the glucose homeostasis in diabetes. Indeed, within the diabetic group, ATP levels showed a negative relationship with glucose level (P < 0.05) and 2.3 DPG a positive relationship with HbA1 (P < 0.05). In conclusion, higher glycolytic activity is present in young diabetic red cells. This activity as well as ATP and 2.3 DPG levels are related to the degree of short- or long-term diabetic control. These findings stress the importance of a careful metabolic control to avoid haematological disturbances.

Adenosine Triphosphate↗
PubMed1991

Interest of zinc determination in leucocyte fractions for the assessment of marginal zinc status.

In order to test the sensitivity of leucocyte zinc determination in the assessment of zinc status, an isolation procedure of mononuclear (MNC) and polymorphonuclear (PMNC) cell fractions was developed. Zinc concentrations in cells from healthy subjects were (mean +/- SD, in mumol/10(10) cells): 0.81 +/- 0.24 in MNC and 0.55 +/- 0.06 in PMNC. In patients suffering from several diseases known to be associated with a marginal impairment in zinc status (cirrhosis, cancer, obesity, endocrine and rheumatic diseases), these concentrations did not differ from those in controls except in rheumatic patients in whom MNC zinc was increased (1.05 +/- 0.42 mumol/10(10) cells) and correlated with erythrocyte sedimentation rate (r = 0.41, P less than 0.01). This relation was also significant in the whole study population (r = 0.39, P less than 0.01). Leucocyte zinc therefore appears to have a limited value in the assessment of marginally impaired zinc status, except in inflammatory states.

Adult↗
PubMed1991

Domestic endotoxin exposure and clinical severity of asthma.

Endotoxins are potent pro-inflammatory substances present in several natural environments and in commercial house dust extracts. To investigate the possible effect of chronic endotoxin exposure on asthma, 28 patients with perennial chronic asthma (20 allergic to house dust mite and eight intrinsic asthmatics) were evaluated during a 4-month period (lung function, clinical and immunological criteria). At the same time, two house dust samples were collected from each patient's home to determine total house dust weight (mg/m2), endotoxin concentration and house dust mite antigen content (evaluated indirectly by guanine content with HPLC method). The mean (+/- s.d.) endotoxin concentration, as measured by quantitative Limulus assay was 2.59 (+/- 3.41) ng/mg house dust, ranging from 0.12 to 20 ng/mg. The mean guanine content was 0.13 (+/- 0.16) mg/100 mg house dust. There was no correlation between endotoxin and house dust mite concentrations. Patients were compared according to the low or high grade exposure to dust, endotoxins and guanine. Compared with patients with low grade (less than or equal to 5.6 ng/ml) exposure, subjects exposed to high endotoxin concentrations (greater than 5.6 ng/ml) showed a significant increase in dyspnea (median 2.6 vs 3.3; P less than 0.05) and treatment (median 14 vs 44.3; P less than 0.01) scores, oral corticosteroid (median 0.0 vs 13.5 mg/24 hr; P less than 0.01) and beta 2-mimetics (median four vs eight puffs/day; P less than 0.01) intake, and a significant decrease in FEV1/FVC (median 84.5 vs 67% of predicted value; P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Carnitine deficiency with cardiomyopathy presenting as neonatal hydrops: successful response to carnitine therapy.

A small-for-date infant presented at birth with severe non-immune hydrops, cardiac failure, metabolic acidosis and hypoglycaemia. Ultrasonography disclosed a cardiomyopathy. Initial therapy consisting of artificial ventilation, inotropes and diuretics resulted in partial disappearance of oedema without significant improvement in cardiac function. Episodes of hypoglycaemia recurred despite continuous glucose infusions. Total serum carnitine from cord blood was 1.65 nmoles/ml and was undetectable on day 20. Oral DL-carnitine supplements resulted in normoglycaemia, dramatic improvement in cardiac function and restoration of serum carnitine levels to normal values. The infant was thereafter maintained on carnitine therapy. Follow-up over 1 year showed moderate growth retardation and normal developmental milestones. In order to account for such a severe neonatal presentation of carnitine deficiency, a combination of defective pre- and postnatal carnitine supply with an inborn error of carnitine handling is considered. The present case illustrates the need for evaluation of carnitine status in fetuses and neonates presenting with hydrops associated with cardiac failure.

Cardiomyopathies↗
PubMed1989

[Usual values of selenium and glutathione peroxidase in a Belgian population].

Several biological parameters for assessing selenium status have been determined in years 1985-1986 in a large Belgian population group, males and females 0 to 92 years old, representative from Brussels and surroundings. In 145 people, 20 to 79 years old, mean concentrations were: 1.06 +/- 0.15 mumol Se/l plasma, 5.0 +/- 1.1 nmol Se/g Hb in erythrocytes and 7.4 +/- 2.0 mu/g Hb for the selenodependent glutathione peroxidase activity measured in erythrocytes (mean +/- standard deviation). Values for urine selenium have a disymmetric distribution and range from 0.05 to 0.65 mumol Se/g creatinine. No difference was evidenced in this group according to sex and age. Children below 20 years and elderly above 80 years have decreased plasma and erythrocyte selenium concentrations but glutathione peroxidase is not modified. These blood selenium concentrations are lower than those determined in a similar population group in years 1980-1981, suggesting a progressive decrease in selenium intake. The concentrations of the biological parameters are not correlated together except in selenium deficient patients having plasma selenium less than 0.75 mumol/l: a significant correlation is observed between plasma selenium and erythrocyte glutathione peroxidase activity, that becomes more intense with decreasing plasma selenium. Finally, two recent investigations are described where a significant response in platelet glutathione peroxidase was obtained during a 60 days selenium supplementation with 100 to 200 micrograms selenium per day, suggesting that usual selenium intake in Belgium (50 micrograms per day) is marginally deficient.

Adolescent↗