Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Marleen Praet is active.

Publication


Featured researches published by Marleen Praet.


JAMA | 2010

Mediastinoscopy vs endosonography for mediastinal nodal staging of lung cancer: a randomized trial.

Jouke T. Annema; Jan P. van Meerbeeck; Robert C. Rintoul; Christophe Dooms; Ellen Deschepper; Olaf M. Dekkers; Paul De Leyn; Jerry Braun; Nicholas R. Carroll; Marleen Praet; Frederick de Ryck; Johan Vansteenkiste; Frank Vermassen; Michel I.M. Versteegh; Maud Veselic; Andrew G. Nicholson; Klaus F. Rabe; Kurt G. Tournoy

CONTEXT Mediastinal nodal staging is recommended for patients with resectable non-small cell lung cancer (NSCLC). Surgical staging has limitations, which results in the performance of unnecessary thoracotomies. Current guidelines acknowledge minimally invasive endosonography followed by surgical staging (if no nodal metastases are found by endosonography) as an alternative to immediate surgical staging. OBJECTIVE To compare the 2 recommended lung cancer staging strategies. DESIGN, SETTING, AND PATIENTS Randomized controlled multicenter trial (Ghent, Leiden, Leuven, Papworth) conducted between February 2007 and April 2009 in 241 patients with resectable (suspected) NSCLC in whom mediastinal staging was indicated based on computed or positron emission tomography. INTERVENTION Either surgical staging or endosonography (combined transesophageal and endobronchial ultrasound [EUS-FNA and EBUS-TBNA]) followed by surgical staging in case no nodal metastases were found at endosonography. Thoracotomy with lymph node dissection was performed when there was no evidence of mediastinal tumor spread. MAIN OUTCOME MEASURES The primary outcome was sensitivity for mediastinal nodal (N2/N3) metastases. The reference standard was surgical pathological staging. Secondary outcomes were rates of unnecessary thoracotomy and complications. RESULTS Two hundred forty-one patients were randomized, 118 to surgical staging and 123 to endosonography, of whom 65 also underwent surgical staging. Nodal metastases were found in 41 patients (35%; 95% confidence interval [CI], 27%-44%) by surgical staging vs 56 patients (46%; 95% CI, 37%-54%) by endosonography (P = .11) and in 62 patients (50%; 95% CI, 42%-59%) by endosonography followed by surgical staging (P = .02). This corresponded to sensitivities of 79% (41/52; 95% CI, 66%-88%) vs 85% (56/66; 95% CI, 74%-92%) (P = .47) and 94% (62/66; 95% CI, 85%-98%) (P = .02). Thoracotomy was unnecessary in 21 patients (18%; 95% CI, 12%-26%) in the mediastinoscopy group vs 9 (7%; 95% CI, 4%-13%) in the endosonography group (P = .02). The complication rate was similar in both groups. CONCLUSIONS Among patients with (suspected) NSCLC, a staging strategy combining endosonography and surgical staging compared with surgical staging alone resulted in greater sensitivity for mediastinal nodal metastases and fewer unnecessary thoracotomies. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00432640.


Lung Cancer | 2009

EBUS-TBNA for the diagnosis of central parenchymal lung lesions not visible at routine bronchoscopy

Kurt G. Tournoy; Robert C. Rintoul; Jan P. van Meerbeeck; Nicholas R. Carroll; Marleen Praet; Robert C. Buttery; Klaas W. van Kralingen; Klaus F. Rabe; Jouke T. Annema

BACKGROUND Obtaining a tissue diagnosis of malignancy is challenging in patients with suspected lung cancer presenting with centrally located intrapulmonary masses. OBJECTIVE (1) To evaluate the yield of endobronchial ultrasound with real-time guided transbronchial needle aspiration (EBUS-TBNA) for diagnosing centrally located lesions after a non-diagnostic conventional bronchoscopy. (2) To assess the impact of EBUS-TBNA on patient management for this indication. STUDY DESIGN AND PATIENTS A retrospective analysis of a series of patients with a central parenchymal lung lesion suspected to be lung cancer who had been referred to three university hospitals for EBUS-TBNA to obtain a tissue diagnosis was undertaken. If EBUS-TBNA did not result in a formal pathological diagnosis of malignancy, patients were subsequently referred for a transthoracic needle aspiration biopsy or a surgical diagnostic procedure. RESULTS Sixty patients were investigated with EBUS-TBNA. The majority (82%) had a prior (non-diagnostic) flexible bronchoscopy. EBUS-TBNA was performed in an out-patient setting in 97%. With ultrasound, the primary lung lesion was observed in all cases. EBUS-TBNA confirmed lung cancer in 46 (77%). A final reference pathology diagnosis was available in 59 (98%) cases. The sensitivity of EBUS-TBNA for diagnosing lung cancer was 82% (95% confidence intervals (CI) 69-91%) with a negative predictive value of 23% (95%CI 5-53%). Based on the EBUS-TBNA findings, transthoracic needle aspiration biopsy or a surgical diagnostic procedure was cancelled in 47% and 30% of patients, respectively. No serious procedure-related complications were reported. CONCLUSION EBUS-TBNA is a sensitive tool for the diagnosis of centrally located primary lung cancer not visible at conventional bronchoscopy. Therefore, EBUS-TBNA can impact on patient management in this setting. However, the low negative predictive value indicates that a negative EBUS-TBNA result should be confirmed by other methods. IMPLICATION EBUS-TBNA can be considered as a diagnostic test in patients with a centrally located lung lesion after a previous non-diagnostic conventional bronchoscopy.


Gut | 1992

Concentrations of 5-ASA and Ac-5-ASA in human ileocolonic biopsy homogenates after oral 5-ASA preparations.

M. De Vos; H. Verdievel; Renaat Schoonjans; Marleen Praet; M Bogaert; F. Barbier

Intramucosal 5-aminosalicylic acid (5-ASA) and acetylated 5-ASA (Ac-5-ASA) concentrations were determined in ileocolonic biopsy specimens from 61 patients with irritable bowel syndrome treated for one week with near equimolar doses of different slow release preparations of 5-ASA (Claversal, Asacol, or Pentasa) or azo-bound drugs (Salazopyrin, Dipentum). The transit time in these patients was accelerated by a laxative, metoclopramide, and colonic lavage. The presence of 5-ASA in the mucosa was confirmed by autofluorescence. The highest concentrations of 5-ASA were obtained after Asacol (mean (SEM), 298.5 (37.3) ng/mg wet wt), followed by Claversal 500 mg (108.8 (11.7) ng/mg wet wt) and Pentasa (25.7 (2.2) ng/mg wet wt). Very low concentrations only were observed after Claversal 250 mg (0.3 (0.03) ng/mg wet wt), Salazopyrine (1.2 (0.1) ng/mg wet wt), and Dipentum (11.0 (3.2) ng/mg wet wt). The results for Ac-5-ASA were similar but the concentrations were generally lower. Serum concentration-time curves over eight hours were obtained from 34 healthy volunteers after a single oral dose of 400 to 500 mg of the different drugs. For the slow release forms, an apparently inverse relationship was found between the area under the curve of the serum concentrations and the intramucosal concentrations, supporting the importance of the local availability of the drug. This inverse relationship was absent for the azo-bound drugs. Colonic washout induced mechanical removal of intraluminal 5-ASA with a secondary disturbance in absorption resulting in a rapid decline in the serum concentrations. However, only for Dipentum did this result in significantly lower 5-ASA mucosal concentrations. This is the first reported attempt to evaluate the mucosal availability of 5-ASA after different oral preparations. It shows that where transit time is accelerated higher mucosal concentrations occur after slow release preparations (except for Claversal 250 mg) than after azo-bound drugs. Additional studies are necessary to correlate these concentrations with clinical effects.


Journal of Clinical Oncology | 2005

Large Cleaved and Immunoblastic Lymphoma May Represent Two Distinct Clinicopathologic Entities Within the Group of Diffuse Large B-Cell Lymphomas

Pascale De Paepe; Ruth Achten; Gregor Verhoef; Iwona Wlodarska; Michel Stul; Vera Vanhentenrijk; Marleen Praet; Chris De Wolf-Peeters

PURPOSE The reliability of immunohistochemistry for subdividing diffuse large B-cell lymphomas (DLBCL) into germinal center B-cell-like (GCB) and non-GCB prognostic subgroups is debated. In this study we evaluated the prognostic significance of such subgrouping on a series of 153 DLBCL patients. Furthermore, we investigated whether both subgroups could comprise clinicopathologic entities recognized by their morphology and characterized by a distinct phenotype, specific genetic abnormalities, and clinical characteristics. PATIENTS AND METHODS All samples from patients were reviewed and morphologically subdivided into large cleaved, immunoblastic, and not otherwise specified DLBCL. GCB and non-GCB immunohistochemical profiles were established. The presence of chromosomal translocations involving BCL2, BCL6, and MYC and/or rearrangements of these genes was investigated. RESULTS Subdividing DLBCL with either a GCB or non-GCB immunophenotypic profile was not of prognostic significance. Nevertheless, CD10 expression was a predictor of favorable outcome, whereas high bcl-2 expression and BCL6 rearrangement were adverse predictors of disease-free survival. Interestingly, large cleaved DLBCL was clearly associated with a GCB immunophenotypic profile, CD10 expression, BCL2 rearrangement, age younger than 60 years, and low to low/intermediate International Prognostic Index risk, but was not of prognostic significance. In contrast, immunoblastic morphology was associated with a non-GCB profile and was a significant predictor of unfavorable DFS. CONCLUSION Subdividing DLBCL into subgroups based on their immunohistochemical profile was not of prognostic significance. Nevertheless, it allowed the additional characterization of two lymphoma subgroups previously recognized in the Working Formulation. Both correspond to two distinct clinicopathologic entities within the DLBCL.


Genes, Chromosomes and Cancer | 2005

PAX5/IGH rearrangement is a recurrent finding in a subset of aggressive B-NHL with complex chromosomal rearrangements

Bruce Poppe; Lucienne Michaux; P De Paepe; Nicole Dastugue; Christian Bastard; Christian Herens; E Moreau; F Cavazzini; Nurten Yigit; H Van Limbergen; A. De Paepe; Marleen Praet; C. De Wolf-Peeters; L. Wlodarska; Franki Speleman

We present an extensive characterization of 10 B‐cell lymphomas with a t(9;14)(p13;q32). The presence of the PAX5/IGH gene rearrangement was demonstrated by fluorescence in situ hybridization (FISH) using a validated probe set, whereas complex karyotypic changes were reassessed by multiplex‐FISH (M‐FISH). Pathologic and clinical review revealed the presence of this rearrangement in 4 histiocyte‐rich, T‐cell‐rich B‐cell lymphomas (HRTR‐BCLs) and 2 posttransplantation diffuse large B‐cell lymphomas (PTLD‐DLBCLs). In contrast to initial observations describing this translocation in lymphoplasmacytic lymphoma (LPL) and LPL‐derived large B‐cell lymphoma, our data showed a wide morphologic and clinical spectrum associated with the PAX5/IGH rearrangement, pointing to an association between this aberration and a subset of de novo DLBCLs presenting with advanced disease and adverse prognosis. In addition, the recurrent incidence of this rearrangement in both HRTR‐BCL (4 cases) and PTLD‐DLBCL (2 cases) was previously unrecognized and is intriguing.


Journal of Acquired Immune Deficiency Syndromes | 2002

Placental inflammation and perinatal transmission of HIV-1.

Fabian Mwanyumba; Philippe Gaillard; Ingrid Inion; Chris Verhofstede; Patricia Claeys; Varsha Chohan; Stijn Vansteelandt; Kishorchandra Mandaliya; Marleen Praet; Marleen Temmerman

&NA; The effect of placental membrane inflammation on mother‐to‐child transmission (MTCT) of HIV‐1 is reported. Placentas from HIV‐1‐infected women were examined as part of a perinatal HIV‐1 project in Mombasa. Kenya. Polymerase chain reaction analysis was used to test for HIV‐1 in the infants at birth and at 6 weeks. The maternal HIV‐1 seroprevalence was 13.3% (298 of 2,235). The overall rate of MTCT of HIV‐1 was 25.4%; polymerase chain reaction analysis revealed that of the 201 infants 6.0% (12) were already HIV‐1‐positive at birth (intrauterine transmission) and 19.4% (39) were infected during the peripartum period or in early neonatal life (perinatal transmission). The prevalence of acute chorioamnionitis was 8.8%, that of deciduitis was 10.8%, and that of villitis was 1.6%. Acute chorioamnionitis was independently associated with peripartum HIV‐1 transmission but not with in utero MTCT (17.9% vs. 6.7%, respectively; adjusted odds ratio, 3.9; 95% confidence interval, 1.2‐12.5; p = .025). Other correlates of perinatal MTCT were presence of HIV in the genital tract and in the babys oral cavity and a high maternal viral load in peripheral blood. The adjusted population attributable fraction of 12.8% (95% confidence interval, 1.5%‐22.8%) indicated that approximately 3% of MTCT could be prevented if acute chorioamnionitis was eliminated. We suggest that further research on the role of antimicrobial treatment in the prevention of chorioamnionitis and the reduction of peripartum MTCT needs to be performed.


Liver Transplantation | 2006

Early immunosuppression withdrawal after living donor liver transplantation and donor stem cell infusion

Vincent Donckier; Roberto Troisi; Alain Le Moine; Michel Toungouz; S Ricciardi; Isabelle Colle; Hans Van Vlierberghe; Ligia Craciun; Myriam Libin; Marleen Praet; Lucien Noens; Patrick Stordeur; Marc Andrien; Micheline Lambermont; Michel Gelin; Nadine Bourgeois; Michael Adler; Bernard de Hemptinne; Michel Goldman

Long‐term results of organ transplantation are still limited by serious side effects of immunosuppressive drugs. A major issue, therefore, is to elaborate novel therapeutic protocols allowing withdrawal or minimization of immunosuppressive therapy after transplantation. We report on 3 patients prospectively enrolled in an original protocol designed to promote graft acceptance in living donor liver transplantation, using posttransplant conditioning with high doses of antithymocyte globulin followed by injection of donor‐derived stem cells. In 2 patients, early immunosuppression withdrawal was possible, without subsequent graft deterioration. In these 2 cases, in vitro studies showed indices of immunological tolerance as assessed by specific hyporesponsiveness to donor alloantigens in mixed lymphocytes culture. In the third patient, acute rejection rapidly occurred after discontinuation of immunosuppression, and minimal immunosuppression has to be maintained during long‐term follow‐up. In this case, a clearly distinct immunoreactive profile was observed as compared to tolerant patients, as no specific modulation of the antidonor response was observed in vitro. Of note, no macrochimerism could be detected in any of the 3 patients during the follow‐up. In conclusion, these clinical observations demonstrated that, despite the absence of macrochimerism, donor stem cells infusion combined with recipient conditioning may allow early immunosuppression withdrawal or minimization after liver transplantation. Liver Transpt 12:1523–1528, 2006.


International Journal of Experimental Pathology | 2008

Comparison of three research models of portal hypertension in mice: macroscopic, histological and portal pressure evaluation.

Anja Geerts; Eline Vanheule; Marleen Praet; Hans Van Vlierberghe; Martine De Vos; Isabelle Colle

The characterization of mice models of portal hypertension (PHT) is lacking in the literature. Therefore, the aim of the present study was to make a histological approach during development of PHT in two models of cirrhosis with PHT compared with one model of isolated PHT. The model of isolated PHT was developed by partial portal vein ligation (PPVL). Two portal hypertensive cirrhotic mice models were developed either by common bile duct ligation (CBDL) or administration of carbon tetrachloride (CCl4) subcutaneously (twice weekly, 1 ml/kg). These models represent, respectively, a secondary biliary cirrhosis and alcoholic cirrhosis. Mice were killed at several time points to evaluate liver changes by histological and ultrastructural methods. A correlation was made with portal pressure measurements. Histology revealed the absence of fibrosis or cirrhosis in PPVL mice. They developed an isolated portal hypertension. After CBDL induction, the mice developed the characteristics of cirrhosis after 6 weeks, with simultaneous increase in portal pressures. Fifty percent of the mice had ascites at that time point. Sixteen weeks after administration of CCl4, a micronodular cirrhotic aspect of the liver was seen associated with signs of portal hypertension. This is the first descriptive study of three widely used animal models in mice, allowing the study of pathophysiological changes in cirrhosis and portal hypertension. The PPVL in mice leads to a model of isolated portal hypertension. Secondary biliary cirrhosis developed after 6 weeks of common bile duct ligation in 50% of the mice that developed ascites. Subcutaneous injection of CCl4 for 16 weeks induces cirrhosis and poral hypertension, without ascites. Moreover, the present study is the first description of a cirrhotic model in mice developed by subcutaneous injections of CCl4. Well‐described mice models will facilitate use of knock‐out or transgenic mice and lead to a better understanding of the underlying molecular pathways in the field of portal hypertension and cirrhosis.


The American Journal of Medicine | 1981

Diquat intoxication: Report of two cases and review of the literature

Raymond Vanholder; Francis Colardyn; Jacques De Reuck; Marleen Praet; Norbert Lameire; Severin Ringoir

Animal experiments have suggested that diquat is less toxic than the more widely used paraquat. In this paper, nine previously reported cases of diquat intoxication are reviewed, together with the description of our personal observations in two additional patients. These two patients, like four other patients described in the literature, died from complications involving the gastrointestinal tract, brain and kidneys. Thus, diquat intoxication is apparently not as innocent as was originally thought. In this paper, special attention has been given to the major clinical differences between diquat and paraquat intoxication. In contrast with the latter, severe diquat intoxication induces gastrointestinal fluid sequestration and is associated with cerebral hemorrhagic lesions and a higher incidence of severe acute renal failure. Despite an asymptomatic clinical interval of up to 48 hours after ingestion, hemoperfusion should be started as soon as possible to prevent toxic levels of diquat in tissue.


Breast Journal | 2009

Prognostic significance of oncogenic markers in ductal carcinoma in situ of the breast: a clinicopathologic study.

Sevilay Altintas; Kathleen Lambein; Manon T. Huizing; Geert Braems; Fernando Tjin Asjoe; Hilde Hellemans; Eric Van Marck; Joost Weyler; Marleen Praet; Rudy Van den Broecke; Jan B. Vermorken; Wiebren A.A. Tjalma

Abstract:  Ductal carcinoma in situ (DCIS) is a heterogeneous malignant condition of the breast with an excellent prognosis. Until recently mastectomy was the standard treatment. As the results of the National Surgical Adjuvant Breast and Bowel Project‐17 trial and the introduction of the Van Nuys Prognostic Index (VNPI) less radical therapies are used. Objectives are to identify clinicopathologic and biologic factors that may predict outcome. Cases of DCIS diagnosed in two Belgian University Centers were included. Paraffin‐embedded material and Hematoxylin and Eosin stained slides of DCIS cases were reviewed and tumor size, margin width, nuclear grade, and comedo necrosis were assessed. Molecular markers (estrogen receptor, progesterone receptor, HER1‐4, Ki67, and c‐myc) were assayed immunohistochemically. Applied treatment strategies were correlated with the prospective use of the VNPI score. Kaplan–Meier survival plots were generated with log‐rank significance and multiple regression analysis was carried out using Cox proportional hazards regression analysis; 159 patients were included with a median age of 54 years (range 29–78); 141 had DCIS and 18 DCIS with microinvasion. The median time of follow‐up was 54 months (range 5–253). Twenty‐three patients developed a recurrence (14.5%). The median time to recurrence was 46 months (range 5–253). Before the introduction of the VNPI, 37.5% of the DCIS patients showed a recurrence while thereafter 6.7% recurred (p < 0.005). Two recurrences occurred in the VNPI group I (7.1%); seven in the VNPI group II (8.5%) (median time to recurrence 66.3 months) and 14 in the VNPI group III (28.5%) (median time to recurrence 40.2 months) (disease‐free survival [DFS]: p < 0.05). A Cox proportional hazards regression analysis indicated that tumor size, margin width, pathologic class, and age were independent predictors of recurrence, but none of the studied molecular markers showed this. Overexpression of HER4 in the presence of HER3 was found to be associated with a better DFS (p < 0.05). This study confirms the value of the VNPI score and questions the benefit of an aggressive approach in the low‐risk DCIS lesions. Independent predictors for recurrence included size, margin width, pathologic class, and age, but none of the molecular markers were part of it. Overexpression of HER4 in the presence of HER3 was associated with a better DFS.

Collaboration


Dive into the Marleen Praet's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

Roberto Troisi

Ghent University Hospital

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Piet Pattyn

Ghent University Hospital

View shared research outputs
Top Co-Authors

Avatar

Kurt G. Tournoy

Ghent University Hospital

View shared research outputs
Top Co-Authors

Avatar

Louis Libbrecht

Ghent University Hospital

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Luc Defreyne

Ghent University Hospital

View shared research outputs
Researchain Logo
Decentralizing Knowledge