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227 Publications visible to you, out of a total of 227
The pore size of PLGA bone implants determines the de novo formation of bone tissue in tibial head defects in rats
Genetical Statistics and Systems Biology

Abstract (Expand)

PURPOSE\backslashr\backslashnThe influence of the pore size of biodegradable poly(lactic-co-glycolic acid) scaffolds on bone regeneration was investigated.\backslashr\backslashnMETHODS\backslashr\backslashnCylindrical … poly(lactic-co-glycolic acid) scaffolds were implanted into a defect in the tibial head of rats. Pore sizes of 100-300, 300-500, and 500-710 \textgreekmm were tested and compared to untreated defects as control. Two and four weeks after implantation, the specimens were explanted and defect regeneration and de novo extracellular matrix generation were investigated by MRI, quantitative solid-state NMR, and mass spectrometry.\backslashr\backslashnRESULTS\backslashr\backslashnThe pore size of the scaffolds had a pronounced influence on the quantity of the extracellular matrix synthesized in the graft; most collagen was synthesized within the first 2 weeks of implantation, while the amount of hydroxyapatite increased in the second 2 weeks. After 4 weeks, the scaffolds contained large quantities of newly formed lamellar bone while the control defects were filled by inhomogenous woven bone. Best results were obtained for scaffolds of a pore size of 300-500 \textgreekmm.\backslashr\backslashnCONCLUSION\backslashr\backslashnOur analysis showed that the structure and dynamics of the regenerated extracellular matrix was very similar to that of the native bone, suggesting that biomineralization was significantly enhanced by the choice of the most appropriate implant material.

Authors: Anja Penk, Yvonne Förster, Holger A. Scheidt, Ariane Nimptsch, Michael C. Hacker, Michaela Schulz-Siegmund, Peter Ahnert, Jürgen Schiller, Stefan Rammelt, Daniel Huster

Date Published: 1st Oct 2013

Publication Type: Journal article

Behandlung der Patienten mit einem Venenastverschluss in Abhängigkeit von der Verschlussdauer
Genetical Statistics and Systems Biology

Abstract (Expand)

PURPOSE\backslashr\backslashnThe aim of this study was to evaluate the effects of intravitreal treatment with bevacizumab (IVB) compared with triamcinolone (IVT) in patients with macular edema due to … branch retinal vein occlusion (BRVO) depending on the duration of BRVO.\backslashr\backslashnMETHODS\backslashr\backslashnA total of 65 BRVO patients were divided into 2 subgroups: group 1 with early treatment (≤ 3 months since onset of BRVO) and group 2 with late treatment (\textgreater 3 months since onset). For the two groups IVB was injected into 17 eyes as early (IVB1) and into 18 eyes as late (IVB2) treatment. For comparison IVT was injected into 14 eyes as early (IVT1) and into 16 eyes as late (IVT2) treatment. Best corrected visual acuity (BCVA) and central retinal thickness (CRT) were analyzed at baseline, 1, 3 and 6 months after treatment.\backslashr\backslashnRESULTS\backslashr\backslashnIn both subgroups a significant improvement of BCVA and CRwas observed. After 6 months, for patients with early treatment, IVB1 showed better results than IVT1 (BCVA: p = 0.008, CRT: p = 0.021). In the late treatment no significant differences between IVT2 and IVB2 were found.\backslashr\backslashnCONCLUSIONS\backslashr\backslashnBevacizumab and triamcinolone significantly improved BCVA and CRT in patients with BRVO. The best BCVA was found if bevacizumab was used as early treatment. In the late treatment no significant differences between bevacizumab and triamcinolone were observed.

Authors: Matus Rehak, E. Spies, Markus Scholz, Peter Wiedemann

Date Published: 1st Oct 2013

Publication Type: Journal article

The role of rs2237781 within GRM8 in eating behavior
Genetical Statistics and Systems Biology

Abstract (Expand)

Introduction:The glutamate receptor, metabotropic 8 gene (GRM8) encodes a G-protein-coupled glutamate receptor and has been associated with smoking behavior and liability to alcoholism implying a role … in addiction vulnerability. Data from animal studies suggest that GRM8 may be involved in the regulation of the neuropeptide Y and melanocortin pathways and might influence food intake and metabolism. This study aimed to investigate the effects of the genetic variant rs2237781 within GRM8 on human eating behavior. Methods:The initial analysis included 548 Sorbs from Germany who have been extensively phenotyped for metabolic traits and who completed the German version of the three-factor eating questionnaire. In addition, we analyzed two independent sample sets comprising 293 subjects from another German cohort and 430 Old Order Amish individuals. Genetic associations with restraint, disinhibition, and hunger were assessed in an additive linear regression model. Results:Among the Sorbs the major G allele of rs2237781 was significantly associated with increased restraint scores in eating behavior (P = 1.9 \times 10(-4); \textgreekb = +1.936). The German cohort and the Old Order Amish population revealed a trend in the same direction for restraint (P = 0.242; \textgreekb = +0.874; P = 0.908; \textgreekb = +0.096; respectively). A meta-analysis resulted in a combined P = 3.1 \times 10(-3) (Z-score 2.948). Conclusion:Our data suggest that rs2237781 within GRM8 may influence human eating behavior factors probably via pathways involved in addictive behavior.

Authors: Marie-Therese Gast, Anke Tönjes, Maria Keller, Annette Horstmann, Nanette Steinle, Markus Scholz, Ines Müller, Arno Villringer, Michael Stumvoll, Peter Kovacs, Yvonne Böttcher

Date Published: 1st Sep 2013

Publication Type: Journal article

Comprehensive high-resolution genomic profiling and cytogenetics of two pediatric and one adult medulloblastoma
Genetical Statistics and Systems Biology

Abstract (Expand)

Medulloblastoma (WHO grade IV) is a rare, malignant, invasive, embryonal tumor which mainly occurs in children and represents less than 1% of all adult brain tumors. Systematic comprehensive genetic … analyses on medulloblastomas are rare but necessary to provide more detailed information. Therefore, we performed comprehensive cytogenetic analyses (blood and tissue) of two pediatric and one adult medulloblastoma, using trypsin-Giemsa staining, spectral karyotyping (tissues only), SNP-arrays, and gene expression analyses. We confirmed frequently detected chromosomal aberrations in medulloblastoma, such as +7q, -8p/q, -9q, -11q, -12q, and +17q and identified novel genetic events. Applying SNP-array, we identified constitutional de novo losses 5q21.1, 15q11.2, 17q21.31, 19p12 (pediatric medulloblastoma), 9p21.1, 19p12, 19q13.3, 21q11.2 (adult medulloblastoma) and gains 16p11.1-16p11.2, 18p11.32, Yq11.223-Yq11.23 (pediatric medulloblastoma), Xp22.31 (adult medulloblastoma) possibly representing inherited causal events for medulloblastoma formation. We show evidence for somatic segmental uniparental disomy in regions 1p36, 6q16.3, 6q24.1, 14q21.2, 17p13.3, and 17q22 not previously described for primary medulloblastoma. Gene expression analysis supported classification of the adult medulloblastoma to the WNT-subgroup and classification of pediatric medulloblastomas to group 3 tumors. Analyses of tumors and matched normal tissues (blood) with a combination of complementary techniques will help to further elucidate potentially causal genetic events for medulloblastomas.

Authors: Heidrun Holland, Li-Xin Xu, Peter Ahnert, Holger Kirsten, Ronald Koschny, Manfred Bauer, Ralf Schober, Jürgen Meixensberger, Wolfgang Krupp

Date Published: 1st Sep 2013

Publication Type: Journal article

Mice overexpressing CD97 in intestinal epithelial cells provide a unique model for mammalian postnatal intestinal cylindrical growth
Genetical Statistics and Systems Biology

Abstract (Expand)

Postnatal enlargement of the mammalian intestine comprises cylindrical and luminal growth, associated with crypt fission and crypt/villus hyperplasia, respectively, which subsequently predominate before … and after weaning. The bipartite adhesion G protein-coupled receptor CD97 shows an expression gradient along the crypt-villus axis in the normal human intestine. We here report that transgenic mice overexpressing CD97 in intestinal epithelial cells develop an upper megaintestine. Intestinal enlargement involves an increase in length and diameter but does not affect microscopic morphology, as typical for cylindrical growth. The megaintestine is acquired after birth and before weaning, independent of the genotype of the mother, excluding altered availability of milk constituents as driving factor. CD97 overexpression does not regulate intestinal growth factors, stem cell markers, and Wnt signaling, which contribute to epithelial differentiation and renewal, nor does it affect suckling-to-weaning transition. Consistent with augmented cylindrical growth, suckling but not adult transgenic mice show enlarged crypts and thus more crypt fissions caused by a transient increase of the crypt transit-amplifying zone. Intestinal enlargement by CD97 requires its seven-span transmembrane/cytoplasmic C-terminal fragment but not the N-terminal fragment binding partner CD55. In summary, ectopic expression of CD97 in intestinal epithelial cells provides a unique model for intestinal cylindrical growth occurring in breast-fed infants.

Authors: Gabriela Aust, Christiane Kerner, Susann Gonsior, Doreen Sittig, Hartmut Schneider, Peter Buske, Markus Scholz, Norman Dietrich, Sindy Oldenburg, Olga N. Karpus, Jörg Galle, Salah Amasheh, Jörg Hamann

Date Published: 15th Jul 2013

Publication Type: Journal article

Alu elements in ANRIL non-coding RNA at chromosome 9p21 modulate atherogenic cell functions through trans-regulation of gene networks
Genetical Statistics and Systems Biology

Abstract (Expand)

The chromosome 9p21 (Chr9p21) locus of coronary artery disease has been identified in the first surge of genome-wide association and is the strongest genetic factor of atherosclerosis known today. … Chr9p21 encodes the long non-coding RNA (ncRNA) antisense non-coding RNA in the INK4 locus (ANRIL). ANRIL expression is associated with the Chr9p21 genotype and correlated with atherosclerosis severity. Here, we report on the molecular mechanisms through which ANRIL regulates target-genes in trans, leading to increased cell proliferation, increased cell adhesion and decreased apoptosis, which are all essential mechanisms of atherogenesis. Importantly, trans-regulation was dependent on Alu motifs, which marked the promoters of ANRIL target genes and were mirrored in ANRIL RNA transcripts. ANRIL bound Polycomb group proteins that were highly enriched in the proximity of Alu motifs across the genome and were recruited to promoters of target genes upon ANRIL over-expression. The functional relevance of Alu motifs in ANRIL was confirmed by deletion and mutagenesis, reversing trans-regulation and atherogenic cell functions. ANRIL-regulated networks were confirmed in 2280 individuals with and without coronary artery disease and functionally validated in primary cells from patients carrying the Chr9p21 risk allele. Our study provides a molecular mechanism for pro-atherogenic effects of ANRIL at Chr9p21 and suggests a novel role for Alu elements in epigenetic gene regulation by long ncRNAs.

Authors: Lesca Miriam Holdt, Steve Hoffmann, Kristina Sass, David Langenberger, Markus Scholz, Knut Krohn, Knut Finstermeier, Anika Stahringer, Wolfgang Wilfert, Frank Beutner, Stephan Gielen, Gerhard Schuler, Gábor Gäbel, Hendrik Bergert, Ingo Bechmann, Peter F. Stadler, Joachim Thiery, Daniel Teupser

Date Published: 4th Jul 2013

Publication Type: Journal article

Risk of tumorigenicity in mesenchymal stromal cell-based therapies–bridging scientific observations and regulatory viewpoints
Genetical Statistics and Systems Biology

Abstract (Expand)

In the past decade, the therapeutic value of mesenchymal stromal cells (MSCs) has been studied in various indications, thereby taking advantage of their immunosuppressive properties. Easy procurement … from bone marrow, adipose tissue or other sources and conventional in vitro expansion culture have made their clinical use attractive. Bridging the gap between current scientific knowledge and regulatory prospects on the transformation potential and possible tumorigenicity of MSCs, the Cell Products Working Party and the Committee for Advanced Therapies organized a meeting with leading European experts in the field of MSCs. This meeting elucidated the risk of potential tumorigenicity related to MSC-based therapies from two angles: the scientific perspective and the regulatory point of view. The conclusions of this meeting, including the current regulatory thinking on quality, nonclinical and clinical aspects for MSCs, are presented in this review, leading to a clearer way forward for the development of such products.

Authors: Lisbeth Barkholt, Egbert Flory, Veronika Jekerle, Sophie Lucas-Samuel, Peter Ahnert, Louise Bisset, Dirk Büscher, Willem Fibbe, Arnaud Foussat, Marcel Kwa, Olivier Lantz, Romaldas Mačiulaitis, Tiina Palomäki, Christian K. Schneider, Luc Sensebé, Gérard Tachdjian, Karin Tarte, Lucie Tosca, Paula Salmikangas

Date Published: 1st Jul 2013

Publication Type: Journal article

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