Equivariant vector bundles on quantum homogeneous spaces

The notion of quantum group equivariant homogeneous vector bundles on quantum homogeneous spaces is introduced. The category of such quantum vector bundles is shown to be exact, and its Grothendieck group is determined. It is also shown that the algebras of functions on quantum homogeneous spaces are noetherian

The podocyte and parietal epithelial cell in proteinuria and glomerulosclerosis.

Contains fulltext : 51043.pdf (publisher's version ) (Open Access)FSGS has become one of the most common glomerular diseases and is characterized by focal and segmental occurrence of lesions. Proteinuria is an important hallmark of glomerular diseases. Based on findings in a mouse model of FSGS we questioned if PECs play a role in human FSGS. Until now epithelial hyperplasia, which can be prominent in FSGS has been attributed to dedifferentiation and proliferation of podocytes. We performed a detailed study of lesions by serial sectioning, marker analysis and three-dimensional reconstruction of glomeruli. Our study demonstrated that the proliferating epithelial cells in FSGS lesions were negative for podocyte and macrophage markers, but stained for PEC markers. Also the staining characteristics of the matrix deposited by these cells was identical to Bowman's capsule. Taken together, these data argue that proliferating epithelial cells in active FSGS lesions are PECs and question the contribution of the socalled 'de-differentiated' podocyte. The concept of the dedifferentiated-proliferating podocyte needs revision. Progressive FSGS will eventually lead to global glomerulosclerosis. Global glomerulosclerosis is often observed in patients with renal disease or patients with nephrosclerosis. Two types of global glomerulosclerosis are described: the obsolescent type and the solidified type. We noticed the presence of abnormal glomeruli in biopsies of children with a recurrent nephrotic syndrome and we have suggested the term involution to describe this process. We have developed a mouse model of glomerular involution. In this model the small glomeruli had the same characteristics as the involuted glomeruli described in children with minimal change disease. Our mouse model will enable us to investigate in more detail the pathogenesis of glomerular involution. We propose a new scheme for the development of FSGS and glomerular involution. We attribute a central role to parietal epithelial cell injury in determining if podocyte injury and proteinuria progress to FSGS or glomerular involution. If confirmed by further studies the PEC might become a new target for therapy.RU Radboud Universiteit Nijmegen, 28 november 2006Promotor : Wetzels, J.F.M. Co-promotores : Assmann, K.J.M., Steenbergen, E.211 p

Exposure to silicone breast implant-infused media is detrimental to Caenorhabditis elegans

Women are raising concerns about breast implant illness (BII), a collective term for a range of symptoms attributed to gel bleed. To study this, Caenorhabditis elegans was exposed to increasing duration of gel bleed from silicone breast implants (SBI) and the impact on health parameters observed. SBI exposure results in a slight reduction in total brood size with the progeny having impaired mobility. Nematodes displayed stress characteristics and silicones were detected inside the animals, suggesting silicone uptake after exposure to SBI. Our data highlights the need for more investigations into the mechanisms and pathways impacted by SBI

Organ distribution of aminopeptidase A and dipeptidyl peptidase IV in normal mice

Contains fulltext : 22650___.PDF (publisher's version ) (Open Access

Automated magnification calibration in transmission electron microscopy using Fourier analysis of replica images.

Item does not contain fulltextThe magnification factor in transmission electron microscopy is not very precise, hampering for instance quantitative analysis of specimens. Calibration of the magnification is usually performed interactively using replica specimens, containing line or grating patterns with known spacing. In the present study, a procedure is described for automated magnification calibration using digital images of a line replica. This procedure is based on analysis of the power spectrum of Fourier transformed replica images, and is compared to interactive measurement in the same images. Images were used with magnification ranging from 1,000 x to 200,000 x. The automated procedure deviated on average 0.10% from interactive measurements. Especially for catalase replicas, the coefficient of variation of automated measurement was considerably smaller (average 0.28%) compared to that of interactive measurement (average 3.5%). In conclusion, calibration of the magnification in digital images from transmission electron microscopy may be performed automatically, using the procedure presented here, with high precision and accuracy

Human epidermal keratinocytes are a source of tenascin-C during wound healing

Contains fulltext : 26009___.PDF (publisher's version ) (Open Access

Lessons from studies on focal segmental glomerulosclerosis: an important role for parietal epithelial cells?

Contains fulltext : 50733.pdf (publisher's version ) (Closed access)Glomerular diseases are caused by multiple mechanisms. Progressive glomerular injury is characterized by the development of segmental or global glomerulosclerosis independent of the nature of the underlying renal disease. Most studies on glomerular disease focus on the constituents of the filtration barrier (podocytes, glomerular basement membrane (GBM), endothelial cells) or the mesangial cells. Little attention is given to the epithelial cells lining Bowman's capsule, the so called parietal epithelial cells (PECs). This 'lack of attention' is partly explained by the presumed 'passive' function of PECs, which are large, flattened cells that cover Bowman's capsule in a single cell layer and form a barrier between the ultrafiltrate and the periglomerular interstitium, in normal glomerular physiology. A more important reason has been the lack of an established primary role for the parietal epithelium in glomerular diseases. However, in recent years, several studies have demonstrated that PECs are involved in extracapillary proliferation. In addition, PECs can become highly active, proliferating cells, expressing many growth factors, chemokines, cytokines, and their receptors. It was recently demonstrated that PECs also play a part in the development of focal segmental glomerulosclerosis (FSGS). This review summarises current knowledge of the PEC, with emphasis on the role of PECs in the development of FSGS

Enhanced activation of dendritic cells by autologous apoptotic microvesicles in MRL/lpr mice

Contains fulltext : 155182.pdf (publisher's version ) (Open Access)INTRODUCTION: Systemic lupus erythematosus is associated with a persistent circulation of modified autoantigen-containing apoptotic debris that might be capable of breaking tolerance. We aimed to evaluate apoptotic microvesicles obtained from lupus or control mice for the presence of apoptosis-associated chromatin modifications and for their capacity to stimulate dendritic cells (DC) from lupus and control mice. METHOD: Apoptotic microvesicles were in vitro generated from splenocytes, and ex vivo isolated from plasma of both MRL/lpr lupus mice and normal BALB/c mice. Microvesicles were analyzed using flow cytometry. Bone marrow-derived (BM)-DC cultured from MRL/lpr or BALB/c mice were incubated with microvesicles and CD40 expression and cytokine production were determined as measure of activation. RESULTS: Microvesicles derived from apoptotic splenocytes or plasma of MRL/lpr mice contained more modified chromatin compared to microvesicles of BALB/c mice, and showed enhanced activation of DC, either from MRL/lpr or BALB/c mice, and consecutively an enhanced DC-mediated activation of splenocytes. The content of apoptosis-modified chromatin in microvesicles of apoptotic splenocytes correlated with their potency to induce interleukin-6 (IL-6) production by DC. Microvesicle-activated MRL/lpr DC showed a significant higher production of IL-6 and tumor growth factor-beta (TGF-beta) compared to BALB/c DC, and were more potent in the activation of splenocytes. CONCLUSION: Apoptotic microvesicles from MRL/lpr mice are more potent activators of DC, and DC from MRL/lpr mice appear relatively more sensitive to activation by apoptotic microvesicles. Our findings indicate that aberrations at the level of apoptotic microvesicles and possibly DC contribute to the autoimmune response against chromatin in MRL/lpr mice

RNA in situ hybridization using digoxigenin-labeled cRNA probes

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