Publications by authors named "Martin Rossa"

5 Publications

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Potential risk factors for early and late dental implant failure: a retrospective clinical study on 9080 implants.

Int J Implant Dent 2020 Nov 30;6(1):81. Epub 2020 Nov 30.

Department of Oral and Maxillofacial Surgery, University Medical Center Mainz, Augustusplatz 2, 55131, Mainz, Germany.

Background: The aim of this study was to analyze potential risk factors for early and late dental implant failure (DIF) in a clinical cohort trial. In a private practice, 9080 implants were inserted during a period of 10 years. In case of DIF, data were classified into early and late DIF and compared to each other in regard of gender, age, site of implantation, implant geometry, and patients' systemic diseases.

Results: Three hundred fifty-one implants failed within the observation period (survival rate: 96.13%). Early DIF occurred in 293 implants (83.48%) compared to late DIF in 58 implants (16.52%). Significant earlier DIF was seen in the mandible (OR = 3.729, p < 0.001)-especially in the posterior area-and in younger patients (p = 0.017), whereas an increased likelihood of late DIF was associated with maxillary implants (OR = 3.729, p < 0.001) and older patients.

Conclusions: Early DIF is about twice as common as late DIF. Main risk factors for early DIF are implant location in the (posterior) mandible as well as younger age. On contrary, late DIF is rather associated with older patients, cancellous bone quality, and longer implants.
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http://dx.doi.org/10.1186/s40729-020-00276-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7701040PMC
November 2020

Unified prebiotically plausible synthesis of pyrimidine and purine RNA ribonucleotides.

Science 2019 10;366(6461):76-82

Center for Integrated Protein Science, Department of Chemistry, LMU München, Butenandtstrasse 5-13, 81377 München, Germany.

Theories about the origin of life require chemical pathways that allow formation of life's key building blocks under prebiotically plausible conditions. Complex molecules like RNA must have originated from small molecules whose reactivity was guided by physico-chemical processes. RNA is constructed from purine and pyrimidine nucleosides, both of which are required for accurate information transfer, and thus Darwinian evolution. Separate pathways to purines and pyrimidines have been reported, but their concurrent syntheses remain a challenge. We report the synthesis of the pyrimidine nucleosides from small molecules and ribose, driven solely by wet-dry cycles. In the presence of phosphate-containing minerals, 5'-mono- and diphosphates also form selectively in one-pot reactions. The pathway is compatible with purine synthesis, allowing the concurrent formation of all Watson-Crick bases.
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http://dx.doi.org/10.1126/science.aax2747DOI Listing
October 2019

Functional impacts of 5-hydroxymethylcytosine, 5-formylcytosine, and 5-carboxycytosine at a single hemi-modified CpG dinucleotide in a gene promoter.

Nucleic Acids Res 2017 Nov;45(19):11033-11042

Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz 55131, Germany.

Enzymatic oxidation of 5-methylcytosine (5-mC) in the CpG dinucleotides to 5-hydroxymethylcytosine (5-hmC), 5-formylcytosine (5-fC) and 5-carboxycytosine (5-caC) has central role in the process of active DNA demethylation and epigenetic reprogramming in mammals. However, it is not known whether the 5-mC oxidation products have autonomous epigenetic or regulatory functions in the genome. We used an artificial upstream promoter constituted of one cAMP response element (CRE) to measure the impact of 5-mC in a hemi-methylated CpG on the promoter activity and further explored the consequences of 5-hmC, 5-fC, and 5-caC in the same system. All modifications induced mild impairment of the CREB transcription factor binding to the consensus 5'-TGACGTCA-3' CRE sequence. The decrease of the gene expression by 5-mC or 5-hmC was proportional to the impairment of CREB binding and had a steady character over at least 48 h. In contrast, promoters containing single 5-fC or 5-caC underwent further progressive loss of activity, up to an almost complete repression. This decline was dependent on the thymine-DNA glycosylase (TDG). The results thus indicate that 5-fC and 5-caC can provide a signal for perpetuation and enhancement of the repressed transcriptional state by a mechanism that requires base excision repair.
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http://dx.doi.org/10.1093/nar/gkx718DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5737506PMC
November 2017

Non-canonical Bases in the Genome: The Regulatory Information Layer in DNA.

Angew Chem Int Ed Engl 2018 04 8;57(16):4296-4312. Epub 2018 Mar 8.

Center for Integrated Protein Science, Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377, Munich, Germany.

Multicellular organisms developed the concept of specialized cells that perform specific functions. Examples are neurons and fibroblast to name just two out of more than 200. These cellular differences are established based on the same sequence information stored in the cell nucleus of all cells of an organism. The sequence information needs consequently different interpretations by the different cell types. During cellular development this interpretation of the genetic code has to be tightly regulated in space and time. Interpretation of the sequence information involves the controlled activation and silencing of specific genes so that certain proteins are made in one cell type but not in others. This involves an additional regulatory information layer beyond the pure base sequence. One aspect of this regulatory information layer relies on functional groups that are attached to the C(5) position of the canonical base dC. Currently four regulatory, non-canonical bases with a methyl (CH )-, a hydroxymethyl (CH OH)-, a formyl (CHO)- and a carboxyl (COOH)- group are known. While 5-methyl-cytidine is long recognised to be a regulatory base in the genome, the other three bases and the enzymes responsible for generating them, were just recently discovered.
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http://dx.doi.org/10.1002/anie.201708228DOI Listing
April 2018

N-methyladenosine (mA) recruits and repels proteins to regulate mRNA homeostasis.

Nat Struct Mol Biol 2017 Oct 4;24(10):870-878. Epub 2017 Sep 4.

Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands.

RNA modifications are integral to the regulation of RNA metabolism. One abundant mRNA modification is N-methyladenosine (mA), which affects various aspects of RNA metabolism, including splicing, translation and degradation. Current knowledge about the proteins recruited to mA to carry out these molecular processes is still limited. Here we describe comprehensive and systematic mass-spectrometry-based screening of mA interactors in various cell types and sequence contexts. Among the main findings, we identified G3BP1 as a protein that is repelled by mA and positively regulates mRNA stability in an mA-regulated manner. Furthermore, we identified FMR1 as a sequence-context-dependent mA reader, thus revealing a connection between an mRNA modification and an autism spectrum disorder. Collectively, our data represent a rich resource and shed further light on the complex interplay among mA, mA interactors and mRNA homeostasis.
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http://dx.doi.org/10.1038/nsmb.3462DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5725193PMC
October 2017