Gene dosage reductions of Trf1 and/or Tin2 induce telomere DNA damage and lymphoma formation in aging mice.

This corrects the article DOI: 10.1038/leu.2015.173.

"Miniguts" from plucked human hair meet Crohn's disease.

Human pluripotent stem cells represent a powerful tool to study human embryonic development and disease but also open up novel strategies for cell replacement therapies. Their capacity to give rise to every cell type of the human body, meanwhile, enables researchers to generate high yields of mesodermal, ectodermal, but also endodermal-derived tissues such as hepatic, pancreatic, or intestinal cells. Another progress in the field came with the advent of 3-dimensional culture conditions, so-called organoids, which facilitate maturation of stem cells and in turn more faithfully recapitulate human tissue architecture. While several studies reported the derivation of organoid cultures from adult intestinal tissue, the derivation of intestinal organoids derived from plucked human hair of Crohn's disease patients has not been reported. The current research project reports such successful generation and characterization of induced pluripotent stem cells (iPSCs) derived from hair sheet keratinocyte cultures of a patient with Crohn's disease. Stepwise differentiation along the intestinal lineage showed no differences in intermediate stages such as definitive endoderm formation. We also directed the patterned primitive gut tube toward intestinal organoids resembling the cellular architecture of human "miniguts". As expected from current pathophysiological knowledge on Crohn's disease, there were no obvious morphological differences in the "miniguts" derived from healthy control and diseased patient-induced pluripotent stem cells. Taken together, our platform will enable for detailed and complementary phenotyping of the pathophysiology of Crohn's disease in a novel disease-in-a-dish format.

[Induced pluripotent stem cells. A new resource in modern medicine]. / Induzierte pluripotente Stammzellen. Eine neue Ressource in der modernen Medizin.

Pluripotent stem cells possess a remarkable unlimited self-renewal capacity and offer unparalleled in vitro differentiation potential. This provides a unique model system not only to study early human development but also gives renewed hope in terms of developing cell therapies and regenerative medicine. S. Yamanaka, a medical doctor and researcher, reported the possibility of reprogramming somatic cells to so-called induced pluripotent stem cells via the ectopic expression of four transcription factors, namely Oct4, Sox2, Klf4 and c-Myc. This Nobel Prize winning work has since revolutionized stem cell research and paved the way for countless new avenues within regenerative medicine. This includes disease modeling in a patient-specific context with the ultimate aim of individually tailored pharmaceutical therapy. Additionally, genetic correction studies have rapidly increased in basic science and thus there is hope that these can be effectively and efficiently translated into clinical applications. Addressing the medical community this review gives a broad general overview about the state of the research field and possible clinical applications of pluripotent stem cells.

A novel splice variant of calcium and integrin-binding protein 1 mediates protein kinase D2-stimulated tumour growth by regulating angiogenesis.

Protein kinase D2 (PKD2) is a member of the PKD family of serine/threonine kinases, a subfamily of the CAMK super-family. PKDs have a critical role in cell motility, migration and invasion of cancer cells. Expression of PKD isoforms is deregulated in various tumours and PKDs, in particular PKD2, have been implicated in the regulation of tumour angiogenesis. In order to further elucidate the role of PKD2 in tumours, we investigated the signalling context of this kinase by performing an extensive substrate screen by in vitro expression cloning (IVEC). We identified a novel splice variant of calcium and integrin-binding protein 1, termed CIB1a, as a potential substrate of PKD2. CIB1 is a widely expressed protein that has been implicated in angiogenesis, cell migration and proliferation, all important hallmarks of cancer, and CIB1a was found to be highly expressed in various cancer cell lines. We identify Ser(118) as the major PKD2 phosphorylation site in CIB1a and show that PKD2 interacts with CIB1a via its alanine and proline-rich domain. Furthermore, we confirm that CIB1a is indeed a substrate of PKD2 also in intact cells using a phosphorylation-specific antibody against CIB1a-Ser(118). Functional analysis of PKD2-mediated CIB1a phosphorylation revealed that on phosphorylation, CIB1a mediates tumour cell invasion, tumour growth and angiogenesis by mediating PKD-induced vascular endothelial growth factor secretion by the tumour cells. Thus, CIB1a is a novel mediator of PKD2-driven carcinogenesis and a potentially interesting therapeutic target.

Crystallographic investigation of cetylpalmitate solid lipid nanoparticles.

Solid lipid nanoparticles (SLN) as alternative intravenous colloidal drug carriers were produced by high pressure homogenisation of the melted lipid cetylpalmitate. The crystallographic properties of the used cetylpalmitate SLN were characterised by small angle X-ray scattering (SAXS) and X-ray diffraction (XRD). It was found that the SLN are available exclusively in a crystalline form. Different cetylpalmitate formulations showed all the same patterns and a uniform crystal lattice was obtained. A partial indexing of the signals of the cetylpalmitate was carried out and the unit cell of the cetylpalmitate was estimated by the Miller indices. A preferred orientation in 001-direction was observed. This can be explained by an impressive lamellar lattice structure of the cetylpalmitate. The results were compared with the crystal data of cetylpalmitate known from literature. There was no correlation with the monoclinic structure known so far. This could indicate that the SLN consist of crystallites of another modification of the cetylpalmitate.

Possible risk considerations for toxic risk assessment.

The concepts of 'negligible', 'tolerable' and 'unacceptable' risk are considered in the context of 'voluntary' and 'involuntary' risks. Levels of risk for different ill health consequences are examined in relation to the various types of risk associated with standard setting and, in particular, for standards relevant to workplace ill-health.

Enterohepatic circulation in rat and dog of 14C-0-[3-(4-less than 2-methoxyphenyl greater than-1-piperazinyl)-2-hydroxypropyl]-3-methoxy-benzaldoxim dihydrochloride and it's demethylated metabolite.

14C-0-[3-(4- less than 2-methoxyphenyl greater than -1-piperazinyl)-2-hydroxypropyl]-3-methoxybenzaldoxim dihydrochloride (HWA 923) was well absorbed (approximately 80%) in rat and dog. In normal animals 37-48% of the radioactivity from a 2 mg/kg of body weight oral or parenteral dose was excreted in the urine, and 48-50% in the faeces. When 14C-HWA 923 was given orally to rats with biliary cannulae, only approximately 10% of the dose was excreted in the urine and approximately 68% appeared in the bile. If bile, collected from animals given 14C-HWA 923, was re-infused intraduodenally into surgically prepared rats, approximately 12% was re-excreted in the urine, and approximately 55% re-excreted in the bile. There were considerably higher levels of radioactivity present in rat blood following intravenous administration of 14C-HWA 923 than after an oral dose, suggesting that radioactivity given via the oral route might be excreted directly into the bile without reaching the systemic circulation. In dog, a significant "first-pass" effect was seen for HWA 923. In a surgically prepared dog, where the bile collection was intermittent, 32% of the dose was excreted in the urine and 46% in the bile. An estimated 73% of the dose would have been present in bile, if continuous collection had taken place. In rat, the major urinary metabolite (up to 40% of the urinary radioactivity) was identified, after specific hydrolysis with beta-glucuronidase, as a demethylated product of HWA 923 by co-chromatography in four solvent systems. This metabolite was present, in rat bile as the conjugates (approximately 40% of the biliary radioactivity), together with significant quantities (approximately 20%) of conjugated HWA 923. The two products were also found on hydrolysis o bile, using gut microflora. Similar results were obtained from dog samples. It is postulated that hydrolysis of the glucuronides of unchanged HWA 923 and its demethylated metabolite by gut micro-flora results in enterohepatic circulation of these two compounds in rat and dog.

The effects of sulphydryl reagents on the binding and mixed function oxidation of hexobarbital in rat hepatic microsomes.

1. The effects of the sulphydryl reagents p-chloromercuribenzoate, N-ethylmaleimide and iodoacetamide on the binding spectrum, oxygen consumption and formation of a suspected substrate-cytochrome P-450-oxygen complex for hexobarbital in rat liver microsomes were investigated. 2. The oxygen consumption caused by hexobarbital oxidation was inhibited non-competitively by all three agents, with 50% inhibition at 4 times 10(-5) M for p-chloromercuribenzoate, 3-7 times 10(-4) M for N-ethylmaleimide and 1-9 times 10(-3) M for iodoacetamide. Cysteamine protected and at least partially reversed this inhibition. 3. p-chloromercuribenzoate inhibited the formation of the cytochrome P-450-substrate-oxygen complex, while N-ethylmaleimide and iodoacetamide also inhibited the formation of this complex but to a lesser extent. The p-chloromercuribenzoate inhibition was protected against and reversed by cysteamine. 4. p-Chloromercuribenzoate and N-ethylmaleimide caused a 50% reduction in the magnitude of the hexobarbital-induced binding spectrum, and this was paralleled by the conversion of cytochrome P-450 to cytochrome P-420. Cysteamine protected against this effect but could not reverse it. Iodoacetamide had no effect on the binding spectrum of hexobarbital and failed to convert cytochrome P-450 to cytochrome P-420. 5. Points of attack within the reaction sequence of drug oxidation are tentatively ascribed to the sulphydryl reagents used in this study.