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A comprehensive analysis of the molecular network of cellular factors establishing and maintaining pluripotency as well as self renewal of pluripotent stem cells is key for further progress in understanding basic stem cell biology. Nanog is necessary for the natural induction of pluripotency in early mammalian development but dispensable for both its maintenance and its artificial induction. To gain further insight into the molecular activity of Nanog, we analyzed the outcomes of Nanog gain-of-function in various cell models employing a recently developed biologically active recombinant cell-permeant protein, Nanog-TAT. We found that Nanog enhances the proliferation of both NIH 3T3 and primary fibroblast cells. Nanog transduction into primary fibroblasts results in suppression of senescence-associated β-galactosidase activity. Investigation of cell cycle factors revealed that transient activation of Nanog correlates with consistent downregulation of the cell cycle inhibitor p27(KIP1) (also known as CDKN1B). By performing chromatin immunoprecipitation analysis, we confirmed bona fide Nanog-binding sites upstream of the p27(KIP1) gene, establishing a direct link between physical occupancy and functional regulation. Our data demonstrates that Nanog enhances proliferation of fibroblasts through transcriptional regulation of cell cycle inhibitor p27 gene., (© 2016. Published by The Company of Biologists Ltd.)

A comprehensive understanding of the functional network of transcription factors establishing and maintaining pluripotency is key for the development of biomedical applications of stem cells. Nanog plays an important role in early development and is essential to induce natural pluripotency in embryonic stem cells (ESCs). Inducible gain-of-function systems allowing a precise control over time and dosage of Nanog activity would be highly desirable to study its vital role in the establishment and maintenance of pluripotency at molecular level. Here we engineered a recombinant cell permeable version of Nanog by fusing it with the cell penetrating peptide TAT. Nanog-TAT can be readily expressed in and purified from E. coli and binds to a consensus Nanog DNA sequence. At cellular level it enhances proliferation and self-renewal of ESCs in the absence of leukemia inhibitory factor (LIF). Nanog-TAT together with LIF acts synergistically as judged by enhanced clonogenicity and activation of an Oct4-promoter-driven GFP reporter gene. Furthermore Nanog-TAT, in the absence of LIF, promotes pluripotency by inhibiting endodermal specification in a Stat3-independent manner. Our results demonstrate that Nanog protein transduction is an attractive tool allowing control over dose and time of addition to the cells for studying the molecular control of pluripotency without genetic manipulation., (Copyright © 2014. Published by Elsevier B.V.)

Cultures of human embryonic stem cell typically rely on protein matrices or feeder cells to support attachment and growth, while mechanical, enzymatic or chemical cell dissociation methods are used for cellular passaging. However, these methods are ill defined, thus introducing variability into the system, and may damage cells. They also exert selective pressures favouring cell aneuploidy and loss of differentiation potential. Here we report the identification of a family of chemically defined thermoresponsive synthetic hydrogels based on 2-(diethylamino)ethyl acrylate, which support long-term human embryonic stem cell growth and pluripotency over a period of 2-6 months. The hydrogels permitted gentle, reagent-free cell passaging by virtue of transient modulation of the ambient temperature from 37 to 15 °C for 30 min. These chemically defined alternatives to currently used, undefined biological substrates represent a flexible and scalable approach for improving the definition, efficacy and safety of human embryonic stem cell culture systems for research, industrial and clinical applications.

In a study of 90 patients in whom a hipjoint had been replaced for the first time using polymethylmetacrylate cement, the extent of intraoperative pulmonary gas exchange disorders was established. The effect of a preexisting disorder of lung function was determined. We checked whether an appraisal of the risk patients who are operated on can be assisted by a preoperative analysis of lung function. After preoperative diagnosis of lung function, the arterial blood gases were analysed at defined times during the operation. An intraoperative fall in the partial pressure of oxygen and an increase in carbon dioxide partial pressure in the arterial blood were found in all patients. There were pronounced interindividual differences in the extent of the disorder of pulmonary gas exchange. The degree of severity of the respective acute disorder of lung function did not show any correlation with the pre-existing disorder of pulmonary ventilation. Major hemodynamic changes were not observed. According to the present findings, a definitive statement with regard to the degree of severity of intraoperatively occurring disorders of pulmonary function cannot be expected from a preoperative analysis of pulmonary function.

Report about the Marburg Hybrid THA using a cementless cup and a cemented stem. The acetabular component consists of an hemispheric inner polyethylene cup and an outer five-layer sintered titanium wire mesh fused together. The socket is primarily anchored by one peg as well as 2 self-stabilizing titanium nails. The forged titanium alloy stems are meeting all the requirements of the latest biomechanic research. A total of 292 Hybrid THA were implanted in 273 patients from 1. 8. 1986 to 1. 1. 1989. 6 patients (2.1%) had to undergo THA exchange surgery (1 early, 3 late infections, 1 acetabular fracture after fall, 1 loosened stem). The clinical data of 62 patients (21.2%) had to be disregarded for various reasons. Thus the data of 212 (72.6%) implanted THA in 194 patients were analyzed. 204 of the analyzed THA (96.2%) judged the result of the operation as good or very good. Radiolucency at the bone-titanium-interface of the cementless cups was present in 60 of 212 cases (28.3%), in revision operations twice as often as in primary implantations. There were no signs of progression. Radiolucency at the bone-cement-interface of the cemented stems was present in 27 of 212 cases (12.8%), with radiolucencies > 1 mm only occurring in area 7 of Gruen (1979). The overall results are thus very promising and support the concept of a hybrid solution for THA.

A nineteen year old female was admitted to the hospital presenting with sudden onset of severe jaundice and the biochemical constellation of cholestasis. The sonographically and radiologically diagnosis of choledochal cyst was confirmed intraoperatively. The choledochal cyst of type IVa reached from the papilla until the hepatocholedochal junction. A lateroterminal choledochojejunostomy with a Y-Roux-anastomosis was constructed. The patient became symptom-free after the operation.