Publications by authors named "Jan-Willem Leeuwis"

Aims: Large B cell lymphoma with IRF4 rearrangement (LBCL-IRF4) is a new entity in the 2017 revised World Health Organisation (WHO) classification that was initially mainly reported in children. After identification of a 79-year-old patient, we assessed how often IRF4 rearrangements can be detected in adult diffuse large B cell lymphomas (DLBCLs) which have to be reclassified to LBCL-IRF4 based on fluorescence in-situ hybridisation (FISH) for IRF4.

Methods And Results: With FISH, we studied the presence of IRF4 rearrangements in 238 lymphomas that were diagnosed as DLBCL according to the previous WHO classification of 2008.

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Unlabelled: Despite high mortality rates of COVID-19-associated pulmonary aspergillosis (CAPA) in the ICU, antifungal prophylaxis remains a subject of debate. We initiated nebulized conventional amphotericin B (c-AmB) as antifungal prophylaxis in COVID-19 patients on invasive mechanical ventilation (IMV).

Objectives: To assess the CAPA incidence in COVID-19 patients on IMV treated with and without nebulized c-AmB as antifungal prophylaxis.

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Background: Immunotherapy, targeting programmed death-1 (PD-1) enhances antitumor T-cell activity in patients with malignancies. Blocking PD-1 or its ligand may lead to fulminant colitis as serious adverse event in these patients. Since little is known of the presence and role of PD-1T cells in colitis of different etiologies, we determined PD-1T cells in mucosal specimens of patients with inflammatory bowel disease, infectious colitis (InfC), immunotherapy-related colitis (ImC) and healthy controls (HC).

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Digital pathology with whole-slide imaging (WSI) has a large potential to make the process of expert consultation and expert panel diagnosis more rapid and more efficient. However, comparison with the current methods is necessary for validation of the technique. In this study, we determined if digital assessment of whole-slide images of hematopathology specimens with a focus on the assessment of lymphoma can be used for consultation and panel diagnostics.

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Spindle cell hemangioma (SCH) is a distinct vascular soft-tissue lesion characterized by cavernous blood vessels and a spindle cell component mainly occurring in the distal extremities of young adults. The majority of cases harbor heterozygous mutations in IDH1/2 sporadically or rarely in association with Maffucci syndrome. However, based on mosaicism and accordingly a low percentage of lesional cells harboring a mutant allele, detection can be challenging.

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Follicular lymphoma with progression to a high-grade lymphoma bears a poor prognosis. We describe a case of a 60-year-old man who presented in 2012 with an epidural mass, diagnosed as a diffuse large B-cell lymphoma (DLBCL) with concurrent low-grade follicular lymphoma. Three years later, the patient presented with a cervical mass, diagnosed as a lymphoblastic lymphoma (LBL).

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Treatment with rhBMP7 exerts profound protective effects in a wide variety of experimental models of renal disease. However, little is known about how these protective effects are mediated, and which cells in the kidney are targeted by exogenous rhBMP7 treatment. To determine if rhBMP7 increases glomerular and tubulointerstitial canonical BMP signaling, we performed Unilateral Ureteral Obstruction (UUO, a widely used obstructive nephropathy model) in mice reporting transcriptional activity downstream of canonical BMP signaling by the expression of GFP under the BMP Responsive Element of the Id1 promoter (BRE:gfp mice).

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Connective tissue growth factor (CTGF; CCN2) plays a role in the development of diabetic nephropathy (DN). Urinary CTGF (uCTGF) is elevated in DN patients and has been proposed as a biomarker for disease progression, but it is unknown which pathophysiological factors contribute to elevated uCTGF. We studied renal handling of CTGF by infusion of recombinant CTGF in diabetic mice.

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Rupture of a splenic artery aneurysm is a rare event associated with high mortality rates. Aneurysm of the splenic artery associated with fibromuscular dysplasia (FMD) is even rarer, with only 3 previously reported cases. We report a patient with previously undiagnosed FMD who required emergent intervention because of a ruptured splenic aneurysm.

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Early retinal vascular changes in the development of diabetic retinopathy (DR) include capillary basal lamina (BL) thickening, pericyte loss and the development of acellular capillaries. Expression of the CCN (connective tissue growth factor/cysteine-rich 61/nephroblastoma overexpressed) family member CCN2 or connective tissue growth factor (CTGF), a potent inducer of the expression of BL components, is upregulated early in diabetes. Diabetic mice lacking one functional CTGF allele (CTGF⁺/⁻) do not show this BL thickening.

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A 74-year-old woman with longlasting rheumatoid arthritis came to our clinic because of a swollen bursa olecrani. Aspiration of the swelling yielded a yellow fluid; polarized light microscopy showed cholesterol crystals.

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Background: Connective Tissue Growth Factor (CTGF/CCN2) is an important mediator of kidney fibrosis. Previous observations indicated that attenuation of CCN2 expression sufficed to alleviate early kidney damage. However, little is known about the role of CCN2 in fibrosis of severely damaged and more chronically injured kidneys.

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Background And Purpose: Unilateral intracranial focal nonprogressive arteriopathy is often found in children with arterial ischemic stroke. We aimed to investigate the course of unilateral intracranial arteriopathy in young adults.

Methods: We searched the Utrecht Stroke Database for patients between 16 and 50 years of age diagnosed with anterior circulation arterial ischemic stroke and a nonatherosclerotic, unilateral intracranial large-artery arteriopathy between 1991 and 2005.

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Bone morphogenetic protein 7 (BMP7) is a key determinant of renal response to injury, exhibiting strong protective as well as regenerative potential in a variety of experimental models. In vitro, beneficial effects of stimulation with BMP7 and other BMPs have been observed in many renal cell types. Still, it remains poorly understood which cells in the native kidney actually respond to BMPs in health and disease.

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Bone morphogenetic protein-6 (BMP-6) suppresses inflammatory genes in renal proximal tubular cells and regulates iron metabolism by inducing hepcidin. In diabetic patients, an increase of myofibroblast progenitor cells (MFPCs), also known as fibrocytes, was found to be associated with decreased BMP-6 expression. We hypothesized that loss of endogenous BMP-6 would aggravate renal injury and fibrosis.

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Background And Purpose: Carotid plaques remodel toward a more stable phenotype after stroke, but not after TIA. Connective tissue growth factor (CTGF) is involved in extracellular matrix production and is expressed in atherosclerotic plaques. We studied the role of CTGF in plaque remodeling after stroke and TIA.

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Injury to the podocytes is the initiating cause of many renal diseases, leading to proteinuria with possible progression to end-stage renal disease. Podocytes are highly specialized cells, with an important role in maintaining the glomerular filtration barrier and producing growth factors for both mesangial cells and endothelial cells. With their foot processes they cover the glomerular basement membrane, and form slit diaphragms with neighboring podocytes.

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The endoderm plays an inductive role in the formation of cardiomyocytes in many vertebrates. Here, we provide further evidence for this in the mouse and demonstrate enhanced cardiomyogenesis in mouse embryonic stem cells cultured in the presence of native visceral endoderm. Isolated mesoderm from late-primitive streak stage mouse embryos that still have an open proamniotic canal had a reduced capacity to form cardiomyocytes after 4 days in culture compared with mesoderm isolated from later stages but prior to cardiomyogenesis.

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Diabetic nephropathy is characterized by decreased expression of bone morphogenetic protein-7 (BMP-7) and decreased podocyte number and differentiation. Extracellular antagonists such as connective tissue growth factor (CTGF; CCN-2) and sclerostin domain-containing-1 (SOSTDC1; USAG-1) are important determinants of BMP signaling activity in glomeruli. We studied BMP signaling activity in glomeruli from diabetic patients and non-diabetic individuals and from control and diabetic CTGF(+/+) and CTGF(+/-) mice.

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