Publications

227 Publications visible to you, out of a total of 227

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PTPN22 620W is regarded as the second most important risk factor for type 1 diabetes and rheumatoid arthritis. Here we describe aspects of the molecular biology of the enzyme and its function, the geographical distribution of the 620W variant, as well as its importance in less frequent rheumatic diseases.

Authors: Inga Melchers, Peter Ahnert

Date Published: 1st Nov 2008

Publication Type: Journal article

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Most meningiomas, accounting for about 20% of intracranial tumors, can be cured by surgical removal. Yet, 8-22% of these tumors are classified as atypical or anaplastic (WHO grade II or III, respectively) presenting with a more aggressive behavior and a high relapse rate. We analyzed genomic alterations of an atypical meningioma using high-density single nucleotide polymorphism arrays (SNP-A) karyotyping combined with GTG-banding, multicolor fluorescence in situ hybridization (M-FISH), and locus-specific FISH. In accordance to recent studies applying SNP-A karyotyping in different malignancies we found that genomic lesions are present at a higher frequency than predicted by traditional cytogenetics. Most of these aberrations have not been described before. Additionally, we unveiled loss of heterozygosity (LOH) without copy number changes on chromosome regions 1p31.1, 2p16.1, 2q23.3, 6q14.1, 6q21, 9p21.1, 10q21.1, and 14q23.3, suggesting partial uniparental disomy (UPD). UPDs are currently considered to play an important role in the initiation and progression of different malignancies. Furthermore, we detected two de novo reciprocal translocations, t(8;19)(q24;q13) and t(10;16)(q22;q12.1). While GTG-banding and M-FISH data suggested balanced translocations, SNP-A analysis clearly demonstrated imbalances in the same region.

Authors: Wolfgang Krupp, Heidrun Holland, Ronald Koschny, Manfred Bauer, Ralf Schober, Holger Kirsten, Michela Livrea, Jürgen Meixensberger, Peter Ahnert

Date Published: 1st Jul 2008

Publication Type: Journal article

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Several small case-control studies have investigated whether factor V Leiden (FVL) is a risk factor for retinal vein occlusion (RVO) and generated conflicting data. To clarify this question we performed a large two-centre case-control study and a meta-analysis of published studies. Two hundred seven consecutive patients with RVO and a control group of 150 subjects were screened between 1996 and 2006. A systematic meta-analysis was done combining our study with further 17 published European case-control studies. APC resistance was detected in 16 out of 207 (7.7%) patients and eight out of 150 (5.3%) controls. The odds ratio (OR) estimated was 1.49 with a (non-significant) 95% confidence interval (CI) of 0.62-3.57. The meta-analysis including 18 studies with a total of 1,748 patients and 2,716 controls showed a significantly higher prevalence of FVL in patients with RVO compared to healthy controls (combined OR 1.66; 95% CI 1.19-2.32). All single studies combined in the meta-analysis were too small to reliably detect the effect individually. This explains the seemingly contradictory data in the literature. In conclusion, the prevalence of APC resistance (and FVL) is increased in patients with RVO compared to controls, but the effect is only moderate. Therefore, there is no indication for general screening of factor V mutation in all patients with RVO. We recommend this test to be performed in patients older than 50 years with an additional history of thromboembolic event and in younger patients without general risk factors like hypertension.

Authors: Matus Rehak, Jiri Rehak, Marc Müller, Susanne Faude, Frank Faude, Annelie Siegemund, Vera Krcova, Ludek Slavik, Dirk Hasenclever, Markus Scholz, Peter Wiedemann

Date Published: 9th Apr 2008

Publication Type: Journal article

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BACKGROUND\backslashr\backslashnThe authors compared the safety and efficacy of a newly developed fast-track concept at their center, including implementation of a direct admission postanesthetic care unit, to standard perioperative management.\backslashr\backslashnMETHODS\backslashr\backslashnAll fast-track patients treated within the first 6 months of implementation of our direct admission postanesthetic care unit were matched via propensity scores and compared with a historical control group of patients who underwent cardiac surgery prior to fast-track implementation.\backslashr\backslashnRESULTS\backslashr\backslashnA total of 421 fast-track patients were matched successfully to 421 control patients. The two groups of patients had a similar age (64 +/- 13 vs. 64 +/- 12 yr for fast-track vs. control, P = 0.45) and European System for Cardiac Operative Risk Evaluation-predicted risk of mortality (4.8 +/- 6.1% vs. 4.6 +/- 5.1%, P = 0.97). Fast-track patients had significantly shorter times to extubation (75 min [45-110] vs. 900 min [600-1140]), as well as shorter lengths of stay in the postanesthetic or intensive care unit (4 h [3.0-5] vs. 20 h [16-25]), intermediate care unit (21 h [17-39] vs. 26 h [19-49]), and hospital (10 days [8-12] vs. 11 days [9-14]) (expressed as median and interquartile range, all P \textless 0.01). Fast-track patients also had a lower risk of postoperative low cardiac output syndrome (0.5% vs. 2.9%, P \textless 0.05) and mortality (0.5% vs. 3.3%, P \textless 0.01).\backslashr\backslashnCONCLUSION\backslashr\backslashnThe Leipzig fast-track protocol is a safe and effective method to manage cardiac surgery patients after a variety of operations. BACKGROUND The authors compared the safety and efficacy of a newly developed fast-track concept at their center, including implementation of a direct admission postanesthetic care unit, to standard perioperative management. METHODS All fast-track patients treated within the first 6 months of implementation of our direct admission postanesthetic care unit were matched via propensity scores and compared with a historical control group of patients who underwent cardiac surgery prior to fast-track implementation. RESULTS A total of 421 fast-track patients were matched successfully to 421 control patients. The two groups of patients had a similar age (64 +/- 13 vs. 64 +/- 12 yr for fast-track vs. control, P = 0.45) and European System for Cardiac Operative Risk Evaluation-predicted risk of mortality (4.8 +/- 6.1% vs. 4.6 +/- 5.1%, P = 0.97). Fast-track patients had significantly shorter times to extubation (75 min [45-110] vs. 900 min [600-1140]), as well as shorter lengths of stay in the postanesthetic or intensive care unit (4 h [3.0-5] vs. 20 h [16-25]), intermediate care unit (21 h [17-39] vs. 26 h [19-49]), and hospital (10 days [8-12] vs. 11 days [9-14]) (expressed as median and interquartile range, all P \textless 0.01). Fast-track patients also had a lower risk of postoperative low cardiac output syndrome (0.5% vs. 2.9%, P \textless 0.05) and mortality (0.5% vs. 3.3%, P \textless 0.01). CONCLUSION The Leipzig fast-track protocol is a safe and effective method to manage cardiac surgery patients after a variety of operations.

Authors: Joerg Ender, Michael Andrew Borger, Markus Scholz, Anne-Kathrin Funkat, Nadeem Anwar, Marcus Sommer, Friedrich Wilhelm Mohr, Jens Fassl

Date Published: 2008

Publication Type: Journal article

Abstract (Expand)

BACKGROUND\backslashr\backslashnOne of the most promising options for treatment of stroke using adult stem cells are human umbilical cord blood (HUCB) cells that were already approved for therapeutic efficacy in vivo. However, complexity of animal models has thus far limited the understanding of beneficial cellular mechanisms. To address the influence of HUCB cells on neuronal tissue after stroke we established and employed a human in vitro model of neuronal hypoxia using fully differentiated vulnerable SH-SY5Y cells. These cells were incubated under an oxygen-reduced atmosphere (O2\textless 1%) for 48 hours. Subsequently, HUCB mononuclear cells (MNC) were added to post-hypoxic neuronal cultures. These cultures were characterized regarding to the development of apoptosis and necrosis over three days. Based on this we investigated the therapeutic influence of HUCB MNC on the progression of apoptotic cell death. The impact of HUCB cells and hypoxia on secretion of neuroprotective and inflammatory cytokines, chemokines and expression of adhesion molecules was proved.\backslashr\backslashnRESULTS\backslashr\backslashnHypoxic cultivation of neurons initially induced a rate of 26% +/- 13% of apoptosis. Hypoxia also caused an enhanced expression of Caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP). Necrosis was only detected in low amounts. Within the next three days rate of apoptosis in untreated hypoxic cultures cumulated to 85% +/- 11% (p \textless or = 0.001). Specific cytokine (VEGF) patterns also suggest anti-apoptotic strategies of neuronal cells. Remarkably, the administration of MNC showed a noticeable reduction of apoptosis rates to levels of normoxic control cultures (7% +/- 3%; p \textless or = 0.001). In parallel, clustering of administered MNC next to axons and somata of neuronal cells was observed. Furthermore, MNC caused a pronounced increase of chemokines (CCL5; CCL3 and CXCL10).\backslashr\backslashnCONCLUSION\backslashr\backslashnWe established an in vitro model of neuronal hypoxia that affords the possibility to investigate both, apoptotic neuronal cell death and neuroprotective therapies. Here we employed the therapeutic model to study neuroprotective properties of HUCB cells. We hypothesize that the neuroprotective effect of MNC was due to anti-apoptotic mechanisms related to direct cell-cell contacts with injured neuronal cells and distinct changes in neuroprotective, inflammatory cytokines as well as to the upregulation of chemokines within the co-cultures. BACKGROUND One of the most promising options for treatment of stroke using adult stem cells are human umbilical cord blood (HUCB) cells that were already approved for therapeutic efficacy in vivo. However, complexity of animal models has thus far limited the understanding of beneficial cellular mechanisms. To address the influence of HUCB cells on neuronal tissue after stroke we established and employed a human in vitro model of neuronal hypoxia using fully differentiated vulnerable SH-SY5Y cells. These cells were incubated under an oxygen-reduced atmosphere (O2\textless 1%) for 48 hours. Subsequently, HUCB mononuclear cells (MNC) were added to post-hypoxic neuronal cultures. These cultures were characterized regarding to the development of apoptosis and necrosis over three days. Based on this we investigated the therapeutic influence of HUCB MNC on the progression of apoptotic cell death. The impact of HUCB cells and hypoxia on secretion of neuroprotective and inflammatory cytokines, chemokines and expression of adhesion molecules was proved. RESULTS Hypoxic cultivation of neurons initially induced a rate of 26% +/- 13% of apoptosis. Hypoxia also caused an enhanced expression of Caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP). Necrosis was only detected in low amounts. Within the next three days rate of apoptosis in untreated hypoxic cultures cumulated to 85% +/- 11% (p \textless or = 0.001). Specific cytokine (VEGF) patterns also suggest anti-apoptotic strategies of neuronal cells. Remarkably, the administration of MNC showed a noticeable reduction of apoptosis rates to levels of normoxic control cultures (7% +/- 3%; p \textless or = 0.001). In parallel, clustering of administered MNC next to axons and somata of neuronal cells was observed. Furthermore, MNC caused a pronounced increase of chemokines (CCL5; CCL3 and CXCL10). CONCLUSION We established an in vitro model of neuronal hypoxia that affords the possibility to investigate both, apoptotic neuronal cell death and neuroprotective therapies. Here we employed the therapeutic model to study neuroprotective properties of HUCB cells. We hypothesize that the neuroprotective effect of MNC was due to anti-apoptotic mechanisms related to direct cell-cell contacts with injured neuronal cells and distinct changes in neuroprotective, inflammatory cytokines as well as to the upregulation of chemokines within the co-cultures.

Authors: Susann Hau, Doreen M. Reich, Markus Scholz, Wilfried Naumann, Frank Emmrich, Manja Kamprad, Johannes Boltze

Date Published: 2008

Publication Type: Journal article

Abstract (Expand)

OBJECTIVE The functional variant C77G (rs17612648) of PTPRC (CD45) was described to confer risk for systemic sclerosis (SSc) in German Caucasians. We analyzed this association in an independent, largerr German cohort. METHODS We genotyped 171 cases and 179 controls. Cases were subgrouped according to sex, autoantibody profiles, or clinical subsets. RESULTS No association of SSc with C77G was detected in the whole dataset, in subgroups, or in combined analyses with a previous study. CONCLUSION The results do not confirm PTPRC C77G as a general and independent risk factor for development of SSc.

Authors: Holger Kirsten, Mechthild Blume, Frank Emmrich, Nico Hunzelmann, Rudolf Mierau, Rita Rzepka, Peter Vaith, Torsten Witte, Inga Melchers, Peter Ahnert

Date Published: 2008

Publication Type: Journal article

Abstract

Not specified

Authors: Markus Scholz, Harald Niesch, Olaf Steffen, Baerbel Ernst, Markus Loeffler, Evelin Witruk, Hans Schwarz

Date Published: 2008

Publication Type: Journal article

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