Nestin Modulates Glucocorticoid Receptor Function by Cytoplasmic Anchoring

Nestin is the characteristic intermediate filament (IF) protein of rapidly proliferating progenitor cells and regenerating tissue. Nestin copolymerizes with class III IF-proteins, mostly vimentin, into heteromeric filaments. Its expression is downregulated with differentiation. Here we show that a strong nestin expression in mouse embryo tissue coincides with a strong accumulation of the glucocorticoid receptor (GR), a key regulator of growth and differentiation in embryonic development. Microscopic studies on cultured cells show an association of GR with IFs composed of vimentin and nestin. Cells lacking nestin, but expressing vimentin, or cells expressing vimentin, but lacking nestin accumulate GR in the nucleus. Completing these networks with an exogenous nestin, respectively an exogenous vimentin restores cytoplasmic anchoring of GR to the IF system. Thus, heteromeric filaments provide the basis for anchoring of GR. The reaction pattern with phospho-GR specific antibodies and the presence of the chaperone HSC70 suggest that specifically the unliganded receptor is anchored to the IF system. Ligand addition releases GR from IFs and shifts the receptor into the nucleus. Suppression of nestin by specific shRNA abolishes anchoring of GR, induces its accumulation in the nucleus and provokes an irreversible G1/S cell cycle arrest. Suppression of GR prior to that of nestin prevents entry into the arrest. The data give evidence that nestin/vimentin specific anchoring modulates growth suppression by GR. We hypothesize that expression of nestin is a major determinant in suppression of anti-proliferative activity of GR in undifferentiated tissue and facilitates activation of this growth control in a precise tissue and differentiation dependent manner

The neurosurgical benefit of contactless in vivo optical coherence tomography regarding residual tumor detection: A clinical study

PurposeIn brain tumor surgery, it is crucial to achieve complete tumor resection while conserving adjacent noncancerous brain tissue. Several groups have demonstrated that optical coherence tomography (OCT) has the potential of identifying tumorous brain tissue. However, there is little evidence on human in vivo application of this technology, especially regarding applicability and accuracy of residual tumor detection (RTD). In this study, we execute a systematic analysis of a microscope integrated OCT-system for this purpose.Experimental designMultiple 3-dimensional in vivo OCT-scans were taken at protocol-defined sites at the resection edge in 21 brain tumor patients. The system was evaluated for its intraoperative applicability. Tissue biopsies were obtained at these locations, labeled by a neuropathologist and used as ground truth for further analysis. OCT-scans were visually assessed with a qualitative classifier, optical OCT-properties were obtained and two artificial intelligence (AI)-assisted methods were used for automated scan classification. All approaches were investigated for accuracy of RTD and compared to common techniques.ResultsVisual OCT-scan classification correlated well with histopathological findings. Classification with measured OCT image-properties achieved a balanced accuracy of 85%. A neuronal network approach for scan feature recognition achieved 82% and an auto-encoder approach 85% balanced accuracy. Overall applicability showed need for improvement.ConclusionContactless in vivo OCT scanning has shown to achieve high values of accuracy for RTD, supporting what has well been described for ex vivo OCT brain tumor scanning, complementing current intraoperative techniques and even exceeding them in accuracy, while not yet in applicability

The value of double balloon enteroscopy (DBE) in the detection and treatment of small bowel bleeding

Hintergrund: Die Doppelballonendoskopie (DBE) ist ein erfolgreiches und zugleich sicheres Verfahren zur Detektion und Therapie von mittleren gastrointestinalen Blutungen. Sie erlaubt ein tiefes Eindringen in den sonst nicht zugänglichen Dünndarm und ermöglicht eine zeitnahe Intervention, was ihr somit einen entscheidenden Vorteil gegenüber der Kapselendoskopie verleiht. Es soll die Frage beantwortet werden, ob die DBE, wie in neueren Studien postuliert, der Goldstandard bei der Detektion und Therapie von mittleren gastrointestinalen Blutungen ist, selbst wenn das Patientenkollektiv nicht nach strengen Einschlusskriterien selektioniert wurde. Methodik: Zwischen Oktober 2004 und März 2008 wurden 119 Untersuchungen an 62 Patienten mit der Indikationsstellung „mittlere gastrointestinale Blutungen“ durchgeführt. Einschlusskriterien waren Patienten mit Teerstuhl, Hämatochezie, Anämie, positiver Hämoccult­test (FOBT) sowie Eisenmangel. Alle bekannten Vorerkrankungen, besonders mit Hinblick auf Kardiovaskuläre, wurden bei unseren Patienten evaluiert. Ein weiteres Augenmerk wurde auf die unterschiedlichen DRG­Vergütungen und die Kostenanalyse einer DBE gelegt. Ergebnisse: Die diagnostische Ausbeute der DBE liegt bei 69%. Die Hauptdiagnose war die Angiodysplasie (22%), gefolgt von Lipidflecken (18%) die zu 100% mit kardiovaskulären Vorerkrankungen vergesellschaftet waren. Bei 53% der Patienten mit Lipidflecken musste wegen Blutungserscheinungen interveniert werden. Insgesamt konnte bei 58% der Patienten mit positivem Befund eine Intervention durchgeführt werden. 91% der DBE’s konnten komplikationslos durchgeführt werden. Schwerwiegende Komplikationen wie Perforation oder Pankreatitis traten nicht auf. Bei der Durchführung einer DBE mit einer Verweildauer von 4 Tagen entstehen der Klinik Kosten in Höhe von 2.342,67 €. Die Vergütung im DRG­System zeigt sich stark abhängig von der angegebenen Diagnose (ICD­Code) und der durchgeführten Prozedur (OPS­Code). Der höchste Ertrag konnte bei APC einer chronischen Eisenmangelanämie oder einer akuten Blutungsanämie, nämlich 3.597,02 €, erzielt werden. Diskussion: Der Einsatz der DBE an einem unselektionierten Patientenkollektiv aus der klinischen Routine zur Diagnostik sowie einer möglichen Intervention von mittleren gastrointestinalen Blutungen zeigt sich weiter als Goldstandard bei der Inspektion des Dünndarms. Trotz der relativ langen Untersuchungszeit sind die hohe diagnostische Ausbeute, die gute therapeutische Wirksamkeit und der komplikationsarme Verlauf wichtige Gründe für eine Anwendung dieser Methode. Die hohe Assoziation von Lipidflecken mit kardiovaskulären Vorerkrankungen und häufigen Blutungsereignissen spricht dafür, dass Lipidlfecken und eine Antikoagulationsmedikation als Risikofaktoren der mittleren gastrointestinalen Blutung (MGIB) anzusehen sind.Background: The double­balloon­endoscopy (DBE) is a successful and safe procedure for detecting and treating mid­gastrointestinal bleedings. It allows deep insertion in the small bowel which is normally difficult to reach and furthermore it offers the immediate chance for intervention. This is the big advantage to the capsule endoscopy. This study aims, whether the DBE is the gold standard procedure by the detection and treatment of mid­gastrointestinal bleedings even in an unselected patient cohort. Methods: Between October 2004 and March 2008 119 examinations have been carried out on 62 patients with the indication of mid­gastrointestinal bleeding. Including criterias were hematochezia, melena, anemia, positive haemoccult­test and iron deficiency. All known pre­existing conditions, especially cardiovascular, were evaluated. Another point of interest was set on the medical treatment by cardiovascular illnesses. Finally, analyses of the different DRG­payments and the total costs for performing one DBE were carried out. Results: The diagnostic yield was 69% and the main diagnoses in all examinations were angiodysplasia (22%), followed by lipid spots (18%). This is a new diagnosis which was related to 100% of patients with cardiovascular illnesses. The combination of lipid spots and a bleeding relevant source appeared in 79% of the 19 patients with lipid spots. Hereby, 53% had to be treated due to the bleeding appearance. The overall therapeutical intervention rate was 58% of all patients with a positive diagnosis. 91% of all DBE’s were performed safely without any complications. Serious complications like perforation or pancreatitis did not occur. The overall costs for carrying out one DBE with a dwell time of 4 days amount to 2.342,67 €. The payment in the DRG­System depends strongly on the given diagnosis (ICD­Code) and the use of APC treatment. The highest amount of money (3.597,02 €) was achieved by APC with the diagnosis of chronic iron deficiency or acute anemia. Discussion: The application of DBE is shown to be the gold standard for diagnosis and possible intervention with the indication of mid­gastrointestinal bleeding even on an unselected patient cohort. In spite of a relative long examination time the high diagnostic yield, the low complication rate and the therapeutical opportunities are good reasons to perform this DBE. The correlation of lipid spots, cardiovascular illnesses and possible bleeding events have to be investigated more in detail, as this could be a new risk factor for mid­gastrointestinal bleeding

Behaviour of precast reinforced concrete columns in moderate seismic conditions

© 2011 Dr. Bidur KafleThis research project contributes towards fulfilling a long-term objective of appropriate seismic evaluation of building structures in regions of low to moderate seismicity such as Australia. Structures such as unreinforced masonry (URM) walls, soft-storey buildings, gravity structures and non-structural components which include free-standing objects are well known to be non-ductile and yet commonly found in regions of low-moderate seismicity. Potential significant degradation in strength in these structural systems in projected earthquake scenarios has been a cause for concern. As the structure, or component, is excited into large displacement (and experiences “rocking” behaviour pertaining to overturning) its effective natural period value is expected to be lengthened into the high period range well above the initial natural period value (as a result of strength and/or stiffness degradation). Consequently, the risk of collapse of the structure is essentially controlled by response spectral parameters in the high period range. Therefore, displacement-controlled behaviour phenomenon applicable to conditions of low to moderate seismic regions has formed the basis for performance evaluation of the structures in this thesis. When the conditions of displacement controlled behaviour are reached the seismic displacement demand on the structure, or component, can become insensitive to any further increase in the natural period of the structure. Seismic assessment is hence much simpler and direct, particularly when the natural period of the structure is variable or difficult to estimate. According to this phenomenon, structures are deemed seismically safe if their displacement capacity exceeds the imposed displacement demand irrespective of their strength and energy dissipation capacity. Results of the tests and complementary analytical simulations of rigid body objects experiencing rocking behaviour revealed that earthquake induced overturning hazards were best represented by the peak displacement demand (PDD) parameter. The increase of probability of overturning with decreasing size of the object has been clearly established from developed fragility curves, importantly demonstrating size effect phenomenon. A conservative model based on the worst scenario of magnitude 7 earthquake and class D site for 5% probability of overturning has also been developed. The understanding of rocking behaviour of rigid objects as observed from the shaking table experiments and analytical simulations was extended to precast reinforced concrete (RC) columns supporting soft-storey system which are nominally connected to the rest of the structure. Field tests conducted on a four-storey soft-storey building supported by precast RC columns in Melbourne, Australia revealed that the columns maintained their gravity load carrying capacity up to a drift of about 8% under quasi-static conditions. The force-displacement relationships of the columns as estimated by a numerical model in Ruaumoko (Carr, 2008) have been found to be in good agreement with those observed from the field tests. It has been found from the developed fragility curves that the probability of failure of precast columns decreases with increasing size of the column, demonstrating the size effect phenomenon. A comparative evaluation study of one low rise (4 storey above ground level) and a high rise (20 storey above ground level) buildings, each with a soft-storey at ground floor level, was conducted which involved assessing existing building stocks using both the conventional force-based procedure as stipulated by current codes of practice (AS1170.4, 2007; AS 3600, 2009) and the more realistic displacement-based procedure which involved non-linear THA of SDOF systems. The risks of collapse of the twenty-storey building were found from the dynamic analyses to be much lower than that of the four-storey building. However, both buildings failed to comply with conventional force-based design requirements. The displacement based approach has highlighted the importance of the effect of size upon the vulnerability to failure of precast RC columns which has not been well captured by conventional force based method

Plasma concentrations of ascorbic acid in a cross section of the German population

Objectives Vitamin C deficiency is considered extremely rare in modern industrialized countries. This study was performed to assess vitamin C concentrations in the German population. Methods As part of a consultant–patient seminar on nutrition and food intolerances, patients were asked to participate in this study on a voluntary basis. Blood samples were taken for analysis of serum vitamin C concentrations, and all patients were asked to complete a questionnaire. The vitamin C concentration was determined by high-performance liquid chromatography. Results Of approximately 300 patients attending the seminar, 188 (62.6%) consented to vitamin C blood sample analysis and 178 (59.3%) answered the questionnaire. The mean vitamin C concentration was 7.98 mg/L (range, 0.50–17.40; reference range, 5–15 mg/L). A low plasma level with vitamin C insufficiency (<5 mg/L) was found in 31 patients (17.4%), and a potential scorbutogenic deficiency (<1.5 mg/L) was found in 6 (3.3%). Conclusions Potential vitamin C insufficiency and deficiency is common. It is therefore possible, even in modern developed populations, that certain individuals may require a higher intake of vitamin C

Co-expression of intermediate filaments glial fibrillary acidic protein and cytokeratin in pituitary adenoma

Purpose!#!To analyze the co-expression of the intermediate filaments GFAP and cytokeratin in 326 pituitary adenomas with regard to the distribution pattern, the subtype of the adenoma and clinical prognostic data.!##!Methods!#!Tissue from 326 pituitary adenomas and 13 normal anterior pituitaries collected in the Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, between 2006 and 2009 was investigated by immunohistochemistry, immunofluorescence and electron microscopy.!##!Results!#!Co-expression of intermediate filaments GFAP and cytokeratin was associated with hormone expression in 62/278 cases (22%), but only found in 2/48 (4%) of null cell adenomas (p &amp;lt; 0.01). Simultaneous co-expression of GFAP and cytokeratin in the same cells was demonstrated in 26 out of 326 pituitary adenomas and in all 13 pituitaries. In pituitary intermediate filaments were demonstrated in a larger area of the cytoplasm than in adenoma (p &amp;lt; 0.01), however, overlapping expression was seen in 2.6% of the total area in both, pituitary and adenoma. Congenially, cells with overlapping expression were found near vessels and in follicles. Furthermore, adenomas with cellular co-expression of GFAP and cytokeratin were associated with a lower recurrence rate (7.7%) compared to adenomas without co-expression of intermediate filaments (17.8%).!##!Conclusions!#!Cellular co-expression of the intermediate filaments GFAP and cytokeratin in pituitary adenomas and the pituitary was demonstrated and shown to be associated with hormone expression and low recurrence rate. The results are discussed with regard to the biology of folliculostellate cells, neural transformation and tumor stem cells. This study may complement the understanding of pituitary adenoma biology