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Dive into the research topics where Walter Foulon is active.

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Featured researches published by Walter Foulon.


American Journal of Obstetrics and Gynecology | 1999

Treatment of toxoplasmosis during pregnancy: A multicenter study of impact on fetal transmission and children’s sequelae at age 1 year ☆ ☆☆ ★

Walter Foulon; Isabelle Villena; Babill Stray-Pedersen; Anne Decoster; Maija Lappalainen; Jean-Michel Pinon; Pål A. Jenum; Klaus Hedman; Anne Naessens

OBJECTIVE Toxoplasmosis during pregnancy can cause fetal infection, with unpredictable sequelae in later life. We measured the effects of prenatal antibiotic therapy on the fetomaternal transmission of Toxoplasma gondii and on the appearance of sequelae in the congenitally infected child at age 1 year. STUDY DESIGN In a multicenter study we investigated consecutive women with Toxoplasma seroconversion during pregnancy. Data were obtained from 144 women recruited in 5 different Toxoplasma reference centers. Through multivariate analysis we assessed the association between transmission and appearance of sequelae as a function of the following parameters: estimated gestational age at infection, administration of antibiotic therapy, duration of antibiotic therapy, and time lapse between infection and the start of antibiotic therapy. RESULTS Sixty-four of the 144 women (44%) gave birth to a congenitally infected infant. Multivariate analysis showed that transmission was predicted neither by whether antibiotics had been administered nor by the time lapse between infection and the start of antibiotic therapy, but only by the gestational age at which maternal infection occurred (P <.0001). Sequelae were found in 19 children (13%), 9 of whom (6%) had severe sequelae. Administration of antibiotics was predictive of the absence of sequelae (P =.026, odds ratio 0.30, 95% confidence interval 0.104-0.863), in particular the absence of severe sequelae (P =.007, odds ratio 0.14, 95% confidence interval 0.036-0.584). The sooner antibiotics were given after the infection, the less frequently sequelae were seen (P =. 021). CONCLUSION Prenatal antibiotic therapy after toxoplasmosis during pregnancy had no impact on the fetomaternal transmission rate but reduced the rate of sequelae among the infected infants. The early start of treatment resulted in a significant reduction in the number of severely affected infants.


The Journal of Pediatrics | 2008

A 10-Year Prospective Study of Sensorineural Hearing Loss in Children with Congenital Cytomegalovirus Infection

Ina Foulon; Anne Naessens; Walter Foulon; Ann Casteels; Frans Gordts

OBJECTIVE To determine the incidence, characteristics, and evolution of sensorineural hearing loss (SNHL) in infants with a congenital cytomegalovirus infection (cCMV). STUDY DESIGN In a prospective 10-year study, 14 021 unselected live-born infants were screened for cCMV by virus isolation in urine. Congenitally infected newborns were evaluated for SNHL during the first 5 years of life. RESULTS A total of 74 of the 14 021 infants (0.53%) were congenitally infected; of these, 4 (5.4%) were symptomatic at birth. Hearing testing could be performed in 60 of the infants. SNHL was found in 21% of the asymptomatic and in 33% of symptomatic congenitally infected infants. Late-onset hearing loss was detected in 5%, progression in 11%, fluctuation in 16%, and improved hearing threshold in 18% of the infants with cCMV. SNHL was observed in 15% of infected infants born after a maternal primary infection, in 7% born after a maternal recurrent infection, and in 40% after a maternal infection of indeterminate timing. CONCLUSIONS In our study population, 0.53% of the infants had cCMV infection, 22% of whom developed SNHL. Long-term follow up and repeated audiologic testing is needed, because progression, fluctuation, improvement, and late-onset hearing loss are important features of cCMV infection. The search for a neonatal screening program to detect all cCMV is worthwhile.


American Journal of Obstetrics and Gynecology | 1999

Prenatal diagnosis of congenital toxoplasmosis: A multicenter evaluation of different diagnostic parameters☆☆☆★

Walter Foulon; Jean-Michel Pinon; Babill Stray-Pedersen; Arnold Pollak; Maija Lappalainen; Anne Decoster; Isabelle Villena; Pål A. Jenum; Michael Hayde; Anne Naessens

OBJECTIVE Our purpose was to evaluate different methods of diagnosing congenital toxoplasmosis prenatally by amniocentesis and cordocentesis. STUDY DESIGN In a retrospective multicenter study, we investigated consecutive women who had seroconversion for Toxoplasma gondii during pregnancy and who underwent either amniocentesis or cordocentesis or both to obtain a prenatal diagnosis of fetal toxoplasmosis. Data were obtained from 122 patients recruited in 6 different European Toxoplasma reference centers. Infants born to these mothers were followed up until 1 year of age to confirm or exclude congenital toxoplasmosis. Sensitivity, specificity, positive predictive value, and negative predictive value were measured for the following parameters: (1) detection of the parasite in amniotic fluid by mouse inoculation, (2) detection of the parasite in amniotic fluid by in vitro cell culture, (3) detection of Toxoplasma deoxyribonucleic acid in amniotic fluid by a polymerase chain reaction assay, (4) detection of the parasite in fetal blood by mouse inoculation, (5) detection of specific immunoglobulin M antibodies in fetal blood, and (6) detection of specific immunoglobulin A antibodies in fetal blood. RESULTS The polymerase chain reaction test performed on amniotic fluid had the highest level of sensitivity (81%) and also a high level of specificity (96%). The combination of the polymerase chain reaction test and mouse inoculation of amniotic fluid increased sensitivity to 91%. The sensitivity of immunoglobulins M and A in fetal blood was 47% and 38%, respectively. In congenitally infected fetuses a negative correlation was observed between positive serologic parameters and gestational age at the time of maternal infection and at prenatal diagnosis. CONCLUSION Congenital toxoplasmosis is best predicted by prenatal examination with the combination of T gondii polymerase chain reaction and mouse inoculation of amniotic fluid. The role of cordocentesis in the diagnosis of congenital toxoplasmosis is limited.


The Journal of Pediatrics | 1999

Diagnosis of congenital toxoplasmosis in the neonatal period: A multicenter evaluation.

Anne Naessens; Pål A. Jenum; Arnold Pollak; Anne Decoster; Maija Lappalainen; Isabelle Villena; Morten Lebech; Babill Stray-Pedersen; Michael Hayde; Jean-Michel Pinon; Eskild Petersen; Walter Foulon

OBJECTIVE To evaluate different laboratory tests used to diagnose congenital toxoplasmosis in the neonatal period. STUDY DESIGN A retrospective multicenter study of 294 pregnant women who experienced seroconversion for Toxoplasma gondii and subsequently delivered live-born infants. Fetal infection was assessed via specific IgM and IgA antibodies (cord and neonatal blood) and detection of T gondii in placenta and cord blood by mouse inoculation. RESULTS Ninety-three (32%) of the 294 infants were congenitally infected. The sensitivity of IgA in cord blood and in neonatal blood was 64% and 66%; the sensitivity of IgM was 41% and 42%, respectively. Mouse inoculation of the placenta and cord blood had sensitivities of 45% and 16%. Positive results of the serologic tests in congenitally infected children correlated significantly with the gestational age at the time of maternal infection but was not significantly influenced by the administration of specific antiparasitic treatment during pregnancy. CONCLUSION Specific T gondii IgA antibody is a more sensitive test than IgM for detecting congenital toxoplasmosis in the neonatal period. The overall specificity is better for serologic tests performed on neonatal blood than for those on cord blood. Neonatal screening with IgM or IgA antibodies will not detect the majority of children with congenital toxoplasmosis when the maternal infection occurred before the 20th week of pregnancy.


Journal of Perinatal Medicine | 2004

Prevention of toxoplasmosis during pregnancy – an epidemiologic survey over 22 consecutive years

Maria Breugelmans; Anne Naessens; Walter Foulon

Abstract Background: Prevention of congenital toxoplasmosis is most often based on the results of a serological screening program in pregnant women followed by prenatal and postnatal treatment of women and their newborns when infection is already established during pregnancy or on cord blood (secondary prevention). Little effort has been made to study primary prevention of toxoplasmosis during pregnancy. Objective: To assess the possibilities of two different programs aimed at preventing the acquisition of toxoplasmosis during pregnancy. Methods: During the first study period (1979–1982) the natural incidence of toxoplasmosis in pregnancy was studied in 2986 pregnant women. In the second study period (1983–1990) the incidence of toxoplasmosis was studied in 8300 women. During this period, seronegative women received a written list of recommendations on how to avoid a toxoplasma infection during pregnancy. In the third study period (1991–2001) the incidence of toxoplasmosis was studied in 16541 women. During this period, the prevention campaign consisted of a leaflet explaining a) toxoplasmosis as a disease and b) what measures should be taken to avoid toxoplasmosis during pregnancy. The third part of the campaign involved a reiteration of these recommendations during antenatal classes held around mid-gestation. The impact of the two prevention programs was studied by measuring the seroconversion rate in seronegative women. Results: Twenty of 1403 seronegative women in the first period (1.43%), 19 of 3605 women in the second period (0.53%) and 8 of 8492 in the third period (0.09%) seroconverted during pregnancy. The first prevention campaign reduced the seroconversion rate by 63% (p<0.05 OR 2.729 95% CI 1.452–5.084). The second prevention program resulted in a reduction rate of 92% compared to the seroconversion rate in the first period (p<0.0001 OR 15.34 95% CI 6.741–34.89). Conclusion: Promotion of simple measures is very effective in the prevention of toxoplasmosis during pregnancy. Primary prevention should not only be based on education about preventive measures given by physicians, but these guidelines should be reiterated during antenatal classes and leaflets distributed containing written recommendations on the nature of the disease and its avoidance.


Clinica Chimica Acta | 2010

FT4 immunoassays may display a pattern during pregnancy similar to the equilibrium dialysis ID–LC/tandem MS candidate reference measurement procedure in spite of susceptibility towards binding protein alterations

Ellen Anckaert; Kris Poppe; Kathleen Van Uytfanghe; Johan Schiettecatte; Walter Foulon; Linda M. Thienpont

BACKGROUND Serum free thyroxine (FT4) testing in pregnancy is known to be challenging for immunoassays (IAs). We verified the reliability of FT4 results by 3 commercial IAs throughout pregnancy, by comparison of the pattern to that obtained with an equilibrium dialysis isotope dilution-mass spectrometry (ED ID-MS) candidate reference measurement procedure. METHODS Pregnant females (107) and age-matched non-pregnant controls (26) were enrolled. The IAs tested were those performed on the Cobas 6000 (Roche Diagnostics), ARCHITECT i2000SR (Abbott Diagnostics) and Immulite 2000 (Siemens Healthcare) platforms. RESULTS Compared to the controls (mean FT4: 18.2pmol/L), ED ID-MS gave in the late first trimester pregnancy an 8.8% lower (p<0.05) mean; in the second trimester it was 29.1% lower (p<0.001), to stabilize in the third trimester (p=0.99). Similar observations were made for the Cobas and Immulite IAs. The ARCHITECT IA showed no significant decrease in the late first trimester (mean 13.5pmol/L versus 13.6pmol/L in controls), but a significant, less pronounced, decrease in the second and third trimesters (15% and 14.4%, respectively). All IAs were susceptible towards alterations in T4 binding proteins during pregnancy. CONCLUSION We proved that IAs may give a FT4 pattern during pregnancy similar to that obtained by ED ID-MS.


Journal of Perinatal Medicine | 2000

Prevention of congenital toxoplasmosis.

Walter Foulon; Anne Naessens; Darrel Ho-Yen

Abstract In utero infection with Toxoplasma gondii may result in congenital defects such as hydrocephalus, chorioretinitis and mental retardation; these defects may be present at birth or may develop later in life. Prevention of this disease can be achieved in different ways. The most effective measure is to prevent the acquisition of the disease during pregnancy by avoiding risk factors for Toxoplasma gondii infection. Health education may decrease the incidence of toxoplasmosis during pregnancy by 60%. A second preventive measure is based on serologic screening during pregnancy to identify infected women. Treatment during pregnancy results in a significant reduction in the incidence of sequelae including severe handicaps. A third possible intervention is treating infected neonates. Antibiotic treatment of infected children has a beneficial effect on the development of sequelae and the sooner therapy is started after birth, the better the outcome. This overview presents the potential benefits and harms of these different options available for the prevention of congenital toxoplasmosis.


Ultrasound in Obstetrics & Gynecology | 2012

Acceptance, reliability and confidence of diagnosis of fetal and neonatal virtuopsy compared with conventional autopsy: A prospective study

Mieke Cannie; C. Votino; Ph. Moerman; R. Vanheste; V. Segers; K. Van Berkel; M. Hanssens; Xin Kang; T. Cos; M. Kir; L. Balepa; L. Divano; Walter Foulon; J. De Mey; Jacques Jani

To compare prospectively maternal acceptance of fetal and neonatal virtuopsy with that of conventional autopsy and to determine the confidence with which magnetic resonance (MR) virtuopsy can be used to diagnose normality/abnormality of various fetal anatomical structures.


Fertility and Sterility | 1986

Recovery of microorganisms in semen and relationship to semen evaluation

Anne Naessens; Walter Foulon; Patrick Debrucker; Paul Devroey; Sabine Lauwers

Semen samples from 120 consecutive unselected men attending our fertility clinic were studied to determine the bacterial isolation rate of semen and its influence on semen quality. Each sample was cultured aerobically, anaerobically, and for Ureaplasma urealyticum and Mycoplasma hominis. The following were analyzed for each semen specimen: motility, morphologic features, and number of sperm cells and viscosity of the ejaculate. Four of the 120 samples had negative results; 101 cultures yielded one or more aerobic organisms (the majority with less than 20,000 microorganisms/ml); 26 yielded anaerobic organisms; and 40 yielded U. urealyticum. No single aerobic or anaerobic organism could be related to abnormal semen samples. Only the presence of U. urealyticum correlated significantly with abnormal semen samples (P less than 0.005). The most affected parameters were the number of spermatozoa (P less than 0.005) and motility (P less than 0.05). We conclude that routine aerobic and anaerobic bacterial cultures of semen are not useful in the clinical evaluation of male infertility. The usefulness of routine screenings for U. urealyticum must be investigated further.


Obstetrics & Gynecology | 2002

Monochorionic high-order multiple pregnancies and multifetal pregnancy reduction

Luc De Catte; Michel Camus; Walter Foulon

OBJECTIVE To study the frequency and obstetric outcome of monochorionic multiple pregnancies in a population referred for fetal reduction. METHODS Data charts of all patients with multifetal (≥3) pregnancies referred for fetal reduction over the last 10 years were reviewed for the presence of monochorionic twin pairs or triplets. RESULTS Twenty‐nine of 239 high‐order multiple pregnancies contained a monochorionic component (12.1%), eight of which were monochorionic triplets. Half of all naturally conceived pregnancies contained a monochori‐onic component. High‐order multiple pregnancies with a monochorionic component resulted significantly more frequently from natural conceptions (7 of 29) than multichorionic pregnancies (7 of 210) (P = .001). Fetal reduction of the monochorionic twin pair in 21 pregnancies resulted in eight twin and 13 singleton pregnancies; mean gestational age at delivery was, respectively, 34.3 ± 2.9 and 39.2 ± 1.4 weeks. Pregnancy loss rate was one of 21 (4.8%). In the remaining eight multiple pregnancies with a monochorionic triplet present, three were complicated by a twin reversed arterial perfusion sequence, and two couples requested a first trimester termination of pregnancy. Fetal reduction of the monochorionic triplet in a dichorionic quadruplet pregnancy resulted in a normal pregnancy outcome. In two monochorionic triplet pregnancies, fetal reduction to monochorionic twin pregnancies with bipolar coagulation of the umbilical cord resulted in a favorable pregnancy outcome. CONCLUSION Monochorionic twins or triplets are frequently part of naturally conceived high‐order multiple pregnancies. Reduction of the monochorionic twin pairs improves pregnancy outcome. Monochorionic triplet pregnancies show a high complication rate, but may benefit from fetal reduction by cord coagulation.

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Anne Naessens

Vrije Universiteit Brussel

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Luc De Catte

Vrije Universiteit Brussel

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Jacques Jani

Université libre de Bruxelles

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C. Votino

Vrije Universiteit Brussel

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Mieke Cannie

Vrije Universiteit Brussel

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Mina Leyder

Vrije Universiteit Brussel

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T. Cos

Université libre de Bruxelles

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Ina Foulon

Vrije Universiteit Brussel

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Sabine Lauwers

Vrije Universiteit Brussel

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Frans Gordts

Vrije Universiteit Brussel

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