Publications by authors named "Minou Oostveen"

3 Publications

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The role of imaging in the initial investigation of paediatric renal tumours.

Lancet Child Adolesc Health 2020 03 31;4(3):232-241. Epub 2020 Jan 31.

Department of Paediatric Radiology, Great Ormond Street Hospital NHS Foundation Trust, London, UK.

Imaging has a key role in the assessment of paediatric renal tumours, especially when the initial treatment approach is to proceed to standard chemotherapy without histological confirmation. In Europe, according to the International Society of Paediatric Oncology guidelines, core needle biopsy is not routinely done unless the child is older than 10 years. Between age 6 months and 9 years, the child is treated with a standard regimen of preoperative chemotherapy unless there are concerns about non-Wilms' tumour pathology. Atypical imaging findings could therefore stratify a child into a different treatment protocol, and can prompt the need for pretreatment histology. This review details the latest protocols and techniques used in the assessment of paediatric renal tumours. Important imaging findings are discussed, especially the features that might prompt the need for a pretreatment biopsy. Local radiology practices vary, but both MRI and CT are widely used as routine imaging tests for the assessment of paediatric renal tumours in Europe. Advances in imaging technology and MRI sequences are facilitating the development of new techniques, which might increase the utility of imaging in terms of predicting tumour histology and clinical behaviour. Several of these new imaging techniques are outlined here.
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http://dx.doi.org/10.1016/S2352-4642(19)30340-2DOI Listing
March 2020

Embryonal precursors of Wilms tumor.

Science 2019 12;366(6470):1247-1251

Wellcome Sanger Institute, Hinxton CB10 1SA, UK.

Adult cancers often arise from premalignant clonal expansions. Whether the same is true of childhood tumors has been unclear. To investigate whether Wilms tumor (nephroblastoma; a childhood kidney cancer) develops from a premalignant background, we examined the phylogenetic relationship between tumors and corresponding normal tissues. In 14 of 23 cases studied (61%), we found premalignant clonal expansions in morphologically normal kidney tissues that preceded tumor development. These clonal expansions were defined by somatic mutations shared between tumor and normal tissues but absent from blood cells. We also found hypermethylation of the locus, a known driver of Wilms tumor development, in 58% of the expansions. Phylogenetic analyses of bilateral tumors indicated that clonal expansions can evolve before the divergence of left and right kidney primordia. These findings reveal embryonal precursors from which unilateral and multifocal cancers develop.
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http://dx.doi.org/10.1126/science.aax1323DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6914378PMC
December 2019

Protection of flavonoids against lipid peroxidation: the structure activity relationship revisited.

Free Radic Res 2002 May;36(5):575-81

Faculty of Medicine, Department of Pharmacology and Toxicology, University of Maastricht, The Netherlands.

The inhibition of the lipid peroxidation, induced by iron and ascorbate in rat liver microsomes, by phenols and flavones was studied. The activity of phenol was enhanced by electron donating substituents, denoted by the Hammett sigma (sigma). The concentration of the substituted phenols giving 50% inhibition (IC50) of lipid peroxidation gave a good correlation with the sigma of the substituent (ln(1/IC50) = -8.92sigma + 5.80 (R = 0.94, p < 0.05)). In flavones two pharmacophores for the protection against lipid peroxidation were pinpointed: (i) a catechol moiety as ring B and (ii) an OH-group at the 3 position with electron donating groups at the 5 and/or 7 position in the AC-ring. An example of a flavone with the latter pharmacophore is galangin (3,5,7-trihydroxyflavone) where the reactivity of the 3-OH-group is enhanced by the electron donating effect of the 5- and 7-OH-groups. This is comparable to the effect of electron donating substituents on the activity of phenol. The prooxidant activity of flavones has been related to a low half peak oxidation potential (Ep/2). All flavones with a catechol as ring B have very low Ep/2, suggesting that they display a prominent prooxidant activity. In contrast, the Ep/2 varies within the group of flavones with a 3-OH, e.g. TUM 8436 (5,7,3',4'-tetra-O-methyl-quercetin) has a relatively high Ep/2 and is an excellent protector against lipid peroxidation. Apparently amongst the flavones with the pharmacophore in the AC-ring there are good antioxidants that are expected to display no or limited prooxidant properties.
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http://dx.doi.org/10.1080/10715760290025951DOI Listing
May 2002