Automated processing of series of micro-CT scans

For some applications of high-resolution X-ray Tomography (micro-CT) scanning, a large set of similar samples is to be analyzed in order to obtain statistically significant results. The complete process, including the micro-CT scan itself, the reconstruction and the analysis is almost identical for every sample. However, in a typical workflow every step is manually performed for every individual sample. This could be optimised by automation of this process, which results in less human intervention and thus a smaller cost and a lower risk to human error. We developed a reliable method to semi-automatically scan several stacked samples and automatically reconstruct the resulting series of data sets. The reconstruction step includes the manual reconstruction of one data set in order to optimize the reconstruction parameters, which can then be used for the rest of the batch. In future work, the automatic handling of the next step in the micro-CT workflow, 3D analysis, will also be improved

Clinical Significance of Serum Albumin and Implications of FcRn Inhibitor Treatment in IgG-Mediated Autoimmune Disorders

Serum albumin (SA), the most abundant soluble protein in the body, maintains plasma oncotic pressure and regulates the distribution of vascular fluid and has a range of other important functions. The goals of this review are to expand clinical knowledge regarding the functions of SA, elucidate effects of dysregulated SA concentration, and discuss the clinical relevance of hypoalbuminemia resulting from various diseases. We discuss potential repercussions of SA dysregulation on cholesterol levels, liver function, and other processes that rely on its homeostasis, as decreased SA concentration has been shown to be associated with increased risk for cardiovascular disease, hyperlipidemia, and mortality. We describe the anti-inflammatory and antioxidant properties of SA, as well as its ability to bind and transport a plethora of endogenous and exogenous molecules. SA is the primary serum protein involved in binding and transport of drugs and as such has the potential to affect, or be affected by, certain medications. Of current relevance are antibody-based inhibitors of the neonatal Fc receptor (FcRn), several of which are under clinical development to treat immunoglobulin G (IgG)-mediated autoimmune disorders; some have been shown to decrease SA concentration. FcRn acts as a homeostatic regulator of SA by rescuing it, as well as IgG, from intracellular degradation via a common cellular recycling mechanism. Greater clinical understanding of the multifunctional nature of SA and the potential clinical impact of decreased SA are needed; in particular, the potential for certain treatments to reduce SA concentration, which may affect efficacy and toxicity of medications and disease progression

Characterization of the in vivo role of furin using tissue-specific knockout mouse models

Een grote verscheidenheid aan proteïnen, betrokken bij zowel fysiologische als pathologische processen, worden gesynthetiseerd als proproteïnen en vereisen een posttranslationele proteolytische omzetting ter activatie. De proproteïne convertases zijn serine endoproteases die carboxy-terminaal klieven van een basische consensus sequentie.Bij genetische inactivatie of inhibitie van het proproteïne convertase furine werd reeds interferentie met tumorigenese en met activatie van bacteriële toxines en virale mantelproteïnen aangetoond. Aangezien furine alomtegenwoordig tot expressie wordt gebracht, is het niet alleen van belang om de ziektegerelateerde furine substraten te kennen, maar ook de fysiologische furine substraten te bepalen om in geval van een furine-inhiberende therapie mogelijke nevenwerkingen te voorspellen. Het doel van deze studie was het analyseren van de rol van furine in de endocriene pancreas en in de lever. Omdat de algemene furin knockout muis resulteerde in embryonale letaliteit, worden conditionele knockout muismodellen gebruikt om de biologische functie van furine in een volwassen stadium en in gedifferentieerde weefels te onderzoeken. Door de analyse van pancreas-specifieke furine knockout muizen hebben we een in vivo rol van furine ontdekt in de gereguleerde secretieroute, namelijk via een modulatie van de intragranulaire acidificatie. Deze muizen leden aan een type 2 diabetesachtig fenotype, aangezien de verstoorde verzuring aanleiding gaf tot secundaire problemen met gereguleerde insulinesecretie en maturatie.Lever-specifieke furine knockout muizen vertoonden een postnatale groeiretardatie en veranderde lichaamssamenstelling. Een vervangingstherapie met insulin-like growth factor-1 zorgde voor een herstel van de groei. Samengevat werden er door de studie van de weefsel-specifieke inactivatie van furine in muizen onverwachte functionele afwijkingen onthuld. Deze resultaten benadrukken het belang van in vivo onderzoek van de proproteïne convertases.status: publishe

The AlfpCre mouse revisited, evidence for liver steatosis related to growth hormone deficiency

status: publishe

The role of Ly49E receptor expression on murine intraepithelial lymphocytes in intestinal cancer development and progression

Ly49E is a member of the Ly49 family of NK receptors and is distinct from other members of this family on the basis of its structural properties, expression pattern and ligand recognition. Importantly, Ly49E receptor expression is high on small intestinal and colonic intraepithelial lymphocytes (IELs). Intestinal IELs are regulators of the mucosal immune system and contribute to front-line defense at the mucosal barrier, including anti-tumor immune response. Whereas most Ly49 receptors have MHC class-I ligands, we showed that Ly49E is instead triggered by urokinase plasminogen activator (uPA). uPA has been extensively implicated in tumor development, where increased uPA expression correlates with poor prognosis. As such, we investigated the role of Ly49E receptor expression on intestinal IELs in the anti-tumor immune response. For this purpose, we compared Ly49E wild-type mice to Ly49E knockout mice in two established tumor models: Apc(Min/+)-mediated and azoxymethane-induced intestinal cancer. Our results indicate that Ly49E expression on IELs does not influence the development or progression of intestinal cancer

Die israelitischen Propheten

von Wilhelm Caspar

Role of furin in granular acidification in the endocrine pancreas: identification of the V-ATPase subunit Ac45 as a candidate substrate

Furin is a proprotein convertase which activates a variety of regulatory proteins in the constitutive exocytic and endocytic pathway. The effect of genetic ablation of fur was studied in the endocrine pancreas to define its physiological function in the regulated secretory pathway. Pdx1-Cre/loxP furin KO mice show decreased secretion of insulin and impaired processing of known PC2 substrates like proPC2 and proinsulin II. Both secretion and PC2 activity depend on granule acidification, which was demonstrated to be significantly decreased in furin-deficient beta cells by using the acidotrophic agent 3-(2,4-dinitroanilino)-3'amino-N-methyldipropylamine (DAMP). Ac45, an accessory subunit of the proton pump V-ATPase, was investigated as a candidate substrate. Ac45 is highly expressed in islets of Langerhans and furin was able to cleave Ac45 ex vivo. Furthermore, the exact cleavage site was determined. In addition, reduced regulated secretion and proinsulin II processing could be obtained in the insulinoma cell line betaTC3 by downregulation of either furin or Ac45. Together, these data establish an important role for furin in regulated secretion, particularly in intragranular acidification most likely due to impaired processing of Ac45

Differential effects of FcRn antagonists on the subcellular trafficking of FcRn and albumin

The homeostasis of IgG is maintained by the neonatal Fc receptor, FcRn. Consequently, antagonism of FcRn to reduce endogenous IgG levels is an emerging strategy for treating antibody-mediated autoimmune disorders using either FcRn-specific antibodies or an engineered Fc fragment. For certain FcRn-specific antibodies, this approach has resulted in reductions in the levels of serum albumin, the other major ligand transported by FcRn. Cellular and molecular analyses of a panel of FcRn antagonists have been carried out to elucidate the mechanisms leading to their differential effects on albumin homeostasis. These analyses have identified 2 processes underlying decreases in albumin levels during FcRn blockade: increased degradation of FcRn and competition between antagonist and albumin for FcRn binding. These findings have potential implications for the design of drugs to modulate FcRn function.</p