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K Wouters

Publications and source records attributed to K Wouters.

16 recordsLinked to original sources
PubMed2006

Can we predict uranium bioavailability based on soil parameters? Part 1: effect of soil parameters on soil solution uranium concentration.

Present study aims to quantify the influence of soil parameters on soil solution uranium concentration for (238)U spiked soils. Eighteen soils collected under pasture were selected such that they covered a wide range for those parameters hypothesised as being potentially important in determining U sorption. Maximum soil solution uranium concentrations were observed at alkaline pH, high inorganic carbon content and low cation exchange capacity, organic matter content, clay content, amorphous Fe and phosphate levels. Except for the significant correlation between the solid-liquid distribution coefficients (K(d), L kg(-1)) and the organic matter content (R(2)=0.70) and amorphous Fe content (R(2)=0.63), there was no single soil parameter significantly explaining the soil solution uranium concentration (which varied 100-fold). Above pH=6, log(K(d)) was linearly related with pH [log(K(d))=-1.18 pH+10.8, R(2)=0.65]. Multiple linear regression analysis did result in improved predictions of the soil solution uranium concentration but the model was complex.

Adsorption↗
PubMed2006

Can we predict uranium bioavailability based on soil parameters? Part 2: soil solution uranium concentration is not a good bioavailability index.

The present study aimed to quantify the influence of soil parameters on uranium uptake by ryegrass. Ryegrass was established on eighteen distinct soils, spiked with (238)U. Uranium soil-to-plant transfer factors (TF) ranged from 0.0003 to 0.0340kgkg(-1). There was no significant relation between the U soil-to-plant transfer (or total U uptake or flux) and the uranium concentration in the soil solution or any other soil factor measured, nor with the U recovered following selective soil extractions. Multiple linear regression analysis resulted in a significant though complex model explaining up to 99% of variation in TF. The influence of uranium speciation on uranium uptake observed was featured: UO(2)(+2), uranyl carbonate complexes and UO(2)PO(4)(-) seem the U species being preferentially taken up by the roots and transferred to the shoots. Improved correlations were obtained when relating the uranium TF with the summed soil solution concentrations of mentioned uranium species.

Biological Availability↗
PubMed2005

Parity-induced changes in global gene expression in the human mammary gland.

The protective effect of an early first full-term pregnancy in relation to breast cancer risk is well established, but the molecular and cell-specific changes in the human mammary gland involved remain unclear. To identify the molecular changes associated with pregnancy-induced differentiation, we analysed the global gene expression profiles of normal mammary tissues from both a parous and a nulliparous woman, using serial analysis of gene expression. This approach allowed us to identify sets of genes, known and unknown, that are differentially expressed in parous versus age-matched nulliparous mammary gland tissues. The normal mammary gland of a multiparous woman is characterized by several known differentiation markers such as casein kappa, casein beta, keratin 14, CCAAT/enhancer binding protein beta and delta and adipsin. Candidate genes involved in cytoarchitectural remodelling and growth inhibition with a potential role in pregnancy-induced protection against breast cancer were also observed. Several genes that are highly expressed in the nulliparous mammary gland and that are lost after pregnancy, encode for growth promoting, cytoskeletal and extracellular matrix proteins. One of these genes, the small breast epithelial mucin, is almost completely downregulated upon a first full-term pregnancy but is known to be expressed in more than 90% of invasive ductal carcinomas.

Adult↗
PubMed2005

Male sex workers in Antwerp, Belgium: a descriptive study.

The objective of this study was to describe the prevalence of sexually transmitted infections (STI), sociodemographic and behavioural characteristics in a population of male sex workers (MSW) in Antwerp, Belgium. Between September 1999 and March 2004, 129 MSW were reached by Gh@pro, an outreach programme providing preventive health care, free STI check-up and hepatitis B vaccination, to sex workers (SW). Sera were collected from 121 men, urine samples from 115 men and a questionnaire was filled in by 43 MSW. In 45.5% of MSW one or more STI were diagnosed (including hepatitis B), 76% on laboratory testing at first screening, 9% through symptomatology at first visit. The prevalence of HIV was 10.8%, hepatitis B virus (HBV) infection 28.9%, syphilis 12.5%, gonorrhoea 1.7% and Chlamydia trachomatis 9.7%. More than 50% of non-immune MSW completed their three-dose hepatitis B vaccination course. Prevalence of STI is concordant with published data on MSW; this population clearly requests and deserves particular attention and approach. There is an important difference in sociodemographic and behavioural characteristics between MSW working in the red light district and those working on the street. Health promotion should be tailored to the different subpopulations and outreach appears to be a successful tool.

Adolescent↗
PubMed2001

The Sophia Anatomical Infant Nose-Throat (Saint) model: a valuable tool to study aerosol deposition in infants.

Relatively little is known about the variables that influence lung deposition of inhaled aerosols in children. A model of the upper airways of an infant could be a useful tool to study these variables in vitro. The objective of this study was to construct an anatomically correct model of the upper airways of a young child. A routine three-dimensional (3D) CT scan of the skull and neck of a child was selected that included the airway from the nasal cavity down to the subglottic region. The CT scan was edited to obtain an anatomically correct distinction between air and mucosa. Next, a model was constructed with a stereolithographic technique using a UV-sensitive resin. To validate the model, a 3D CT scan of the model was made and compared to the anatomy of the original image. To study aerosol deposition, the model was connected to a breathing simulator. Medical aerosols were delivered to the model by MDI/spacer during stimulated breathing. An upper airway model was made of a 9-month-old child that needed reconstructive surgery for a skull deformity and with normal anatomy of the upper airways. The nasal airway of the model was open for air passage and the oral airway was closed. The CT scan of the model matched the original in vivo CT scan closely. Aerosol deposition measurements showed that dose passing the model, or lung dose, was comparable with in vivo lung deposition data. We have constructed an anatomically correct model of the upper airways of a child, using a stereolithographic method for in vitro studies of aerosol deposition in young children. This model will be used to obtain insight in aerosol treatment that cannot be obtained in vivo.

Aerosols↗
PubMed1999

Lymphocytic colitis: a distinct clinical entity? A clinicopathological confrontation of lymphocytic and collagenous colitis.

BACKGROUND AND AIMS: It is not known whether lymphocytic colitis and collagenous colitis represent different clinical entities or constitute part of a spectrum of disease. METHODS: Detailed clinical features and histological findings were compared in a large series of patients with confirmed lymphocytic and collagenous colitis. RESULTS: Histological diagnosis was confirmed in 96 patients with collagenous colitis and 80 with lymphocytic colitis. Twenty eight per cent of patients with collagenous colitis and 26% of patients with lymphocytic colitis had overlapping but less pronounced histological features. Both groups were equal in terms of age, use of aspirin and non-steroidal anti-inflammatory drugs, associated autoimmune conditions, arthritis, diarrhoea, and abdominal pain. The male:female ratio was 27:73 for collagenous colitis and 45:55 for lymphocytic colitis (p=0.013). Twenty five per cent of patients with collagenous colitis compared with 14% of patients with lymphocytic colitis were active smokers; only 8.3% of patients with collagenous colitis had stopped smoking compared with 23% of patients with lymphocytic colitis (p=0.013). Drug induced disease was suspected for ticlopidine (two collagenous colitis, four lymphocytic colitis) and flutamide (four lymphocytic colitis). Mean duration of symptoms before diagnosis was two months for lymphocytic colitis and four months for collagenous colitis. Overall prognosis was generally mild; 84% of patients with lymphocytic colitis and 74% of patients with collagenous colitis reported resolution or significant improvement (p=0.033). CONCLUSIONS: Collagenous and lymphocytic colitis are similar but not identical. Patients with lymphocytic colitis present somewhat earlier and are less likely to be active smokers. Symptoms are milder and more likely to disappear in lymphocytic colitis. Ticlopidine and flutamide should be added to the list of drugs inducing colitis.

Adult↗
PubMed1999

[Villonodular synovitis of the knee in a 5-year-old child. Apropos of a case].

PURPOSE OF THE STUDY: Case report of a five-year-old boy presenting with a painless swelling of the left knee with decreased range of motion. METHOD: Joint aspiration: fluid rich in red blood cells. X-ray--CT-scan--MRI: pigmented villonodular synovitis suspected. Arthroscopy with synovectomy and biopsy confirmed diagnosis. Because of remaining swelling one month after arthroscopy, intra-articular injection of triamcinolone hexacetonide gave a good result which has been maintained after 2 years. DISCUSSION: Hypothesis on etiology and pathophysiology, differential diagnosis and treatment of Pigmented villonodular synovitis are discussed based on a study of the literature. CONCLUSION: Pigmented villonodular synovitis is a rare condition in children. Association with other congenital disorders such as polyarticular localizations and family-history have been described. The diagnosis has to be proved by a biopsy. MRI seems to be the examination which gives the best information. Surgical treatment is indicated and consists of an arthroscopic synovectomy but which is often incomplete. A postoperative injection of triamcinolone hexacetonide may be the solution to avoid recurrence of Pigmented villonodular synovitis.

Administration, Topical↗
PubMed1998

A pancreatic mucinous cystadenoma in a man with mesenchymal stroma, expressing oestrogen and progesterone receptors.

A 43-year-old man presented with abdominal discomfort caused by relapsing pancreatitis. Radiological examination revealed a multilocular cystic mass in the tail of the pancreas, which was resected. Gross examination showed a multilocular cystic lesion measuring 2.5 cm in diameter and containing clear fluid. Microscopically, a mucinous cystadenoma with mesenchymal stroma was diagnosed. The lesion showed two different components: a cyst lined by a columnar, mucin-secreting epithelium and a moderate cellular stroma composed of spindle cells. The stromal element appeared similar to primitive mesenchyme. Immunohistochemical staining confirmed this origin through vimentin expression and showed moderate to strong nuclear staining with oestrogen and progesterone receptor antibodies. Cystadenomas are rare tumours of the pancreas, but mesenchymal stroma is uncommon in such tumours; it is more frequently described in the liver and the bile ducts, and primarily in women.

Adult↗
PubMed1995

Peripherally localized benign hyperplastic nodules of the prostate.

Approximately one-half of needle-core biopsy samples performed for palpable and/or ultrasonographically hypoechoic focal lesions of the prostate reveal carcinoma. A fraction of the negative biopsy samples are related to benign hyperplastic nodules, localized in the peripheral zone of the prostate. The present study examines the morphology of this particular lesion in surgical specimens obtained after cystoprostatectomy and radical prostatectomy performed for bladder and (small) prostate cancer, respectively. Peripheral hyperplastic nodules occur in 18.5% of this population and are unifocal in one-half of the cases. The mean diameter is 4 (+/- 1.3) mm. Peripheral hyperplastic nodules are characteristically localized posteriorly in the peripheral zone, between the midline and the lateral border of the prostate and often in the vicinity of the boundary of the transition zone. Histologically, they resemble glandulostromal hyperplastic nodules as observed in classic benign nodular hyperplasia of the transition zone. Cystic transformation may occur. The nodules are sometimes surrounded by condensed stroma and atrophic glands. Atypical adenomatous hyperplasia is rarely noticed in this lesion. No pure stromal (leiomyomatous) nodules without glands are seen. The peripheral hyperplastic nodule should be included in the differential diagnosis of focal lesions of the peripheral zone.

Biopsy, Needle↗
PubMed1992

Aplasia of respiratory tract cilia.

We report on ciliary aplasia of the respiratory tract, a rare disorder of the mucociliary apparatus, that is insufficiently recognized as a distinct entity. A culture method for ciliogenesis was developed by our laboratory and offers the advantage of studying cilia free of secondary changes associated with infection. Three cases of primary ciliary aplasia were documented histologically in direct biopsy specimens and also in biopsy specimens cultured specifically for ciliogenesis. Primary ciliary aplasia should be differentiated from secondary ciliary aplasia in which basal bodies are present and ciliogenesis takes place in specific culture. Only hereditary ciliary abnormalities are expressed in cell cultures. We critically review the cases of ciliary aplasia reported to date.

Bronchi↗