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Hackl S, Ng XW, Lu D, Wohland T, Becker CFW. Cytoskeleton-dependent clustering of membrane-bound prion protein on the cell surface. J Biol Chem 2021; 296:100359. [PMID: 33539927 PMCID: PMC7988330 DOI: 10.1016/j.jbc.2021.100359] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 01/26/2021] [Accepted: 01/28/2021] [Indexed: 12/23/2022] Open
Abstract
Prion diseases are a group of neurodegenerative disorders that infect animals and humans with proteinaceous particles called prions. Prions consist of scrapie prion protein (PrPSc), a misfolded version of the cellular prion protein (PrPC). During disease progression, PrPSc replicates by interacting with PrPC and inducing its conversion to PrPSc. Attachment of PrPC to cellular membranes via a glycosylphosphatidylinositol (GPI) anchor is critical for the conversion of PrPC into PrPSc. However, the mechanisms governing PrPC conversion and replication on the membrane remain largely unclear. Here, a site-selectively modified PrP variant equipped with a fluorescent GPI anchor mimic (PrP-GPI) was employed to directly observe PrP at the cellular membrane in neuronal SH-SY5Y cells. PrP-GPI exhibits a cholesterol-dependent membrane accumulation and a cytoskeleton-dependent mobility. More specifically, inhibition of actin polymerization reduced the diffusion of PrP-GPI indicating protein clustering, which resembles the initial step of PrP aggregation and conversion into its pathogenic isoform. An intact actin cytoskeleton might therefore prevent conversion of PrPC into PrPSc and offer new therapeutic angles.
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Affiliation(s)
- Stefanie Hackl
- Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Xue Wen Ng
- Departments of Biological Sciences and Chemistry and Centre for Bioimaging Sciences (CBIS), National University of Singapore (NUS), Singapore
| | - Danqin Lu
- Departments of Biological Sciences and Chemistry and Centre for Bioimaging Sciences (CBIS), National University of Singapore (NUS), Singapore; School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China
| | - Thorsten Wohland
- Departments of Biological Sciences and Chemistry and Centre for Bioimaging Sciences (CBIS), National University of Singapore (NUS), Singapore
| | - Christian F W Becker
- Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria.
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Abstract
Aims Evaluate if treating an unstable femoral neck fracture with a locking plate and spring-loaded telescoping screw system would improve construct stability compared to gold standard treatment methods. Methods A 31B2 Pauwels' type III osteotomy with additional posterior wedge was cut into 30 fresh-frozen femur cadavers implanted with either: three cannulated screws in an inverted triangle configuration (CS), a sliding hip screw and anti-rotation screw (SHS), or a locking plate system with spring-loaded telescoping screws (LP). Dynamic cyclic compressive testing representative of walking with increasing weight-bearing was applied until failure was observed. Loss of fracture reduction was recorded using a high-resolution optical motion tracking system. Results LP constructs demonstrated the highest mean values for initial stiffness and failure load. LP and SHS constructs survived on mean over 50% more cycles and to loads 450 N higher than CS. During the early stages of cyclic loading, mean varus collapse of the femoral head was 0.5° (SD 0.8°) for LP, 0.7° (SD 0.7°) for SHS, and 1.9° (SD 2.3°) for CS (p = 0.071). At 30,000 cycles (1,050 N) mean femoral neck shortening was 1.8 mm (SD 1.9) for LP, 2.0 mm (SD 0.9) for SHS, and 3.2 mm (SD 2.5) for CS (p = 0.262). Mean leg shortening at construct failure was 4.9 mm (SD 2.7) for LP, 8.9 mm (SD 3.2) for SHS, and 7.0 mm (SD 4.3) for CS (p = 0.046). Conclusion Use of the LP system provided similar (hip screw) or better (cannulated screws) biomechanical performance as the current gold standard methods suggesting that the LP system could be a promising alternative for the treatment of unstable fractures of the femoral neck.Cite this article: Bone Joint Res 2020;9(6):314-321.
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Affiliation(s)
- E Bliven
- Institute for Biomechanics, BG Unfallklinik Murnau, Murnau am Staffelsee, Germany
| | - S Sandriesser
- Institute for Biomechanics, BG Unfallklinik Murnau, Murnau am Staffelsee, Germany; Paracelsus Medical University, Salzburg, Austria
| | - P Augat
- Institute for Biomechanics, BG Unfallklinik Murnau, Murnau am Staffelsee, Germany; Paracelsus Medical University, Salzburg, Austria
| | - C von Rüden
- Department for Trauma Surgery, BG Unfallklinik Murnau, Murnau am Staffelsee, Germany; Institute for Biomechanics, Paracelsus Medical University, Salzburg, Austria
| | - S Hackl
- Institute for Biomechanics, BG Unfallklinik Murnau, Murnau am Staffelsee, Germany
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Hackl S, Becker CFW. Prion protein-Semisynthetic prion protein (PrP) variants with posttranslational modifications. J Pept Sci 2019; 25:e3216. [PMID: 31713950 PMCID: PMC6899880 DOI: 10.1002/psc.3216] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 08/23/2019] [Accepted: 08/23/2019] [Indexed: 12/16/2022]
Abstract
Deciphering the pathophysiologic events in prion diseases is challenging, and the role of posttranslational modifications (PTMs) such as glypidation and glycosylation remains elusive due to the lack of homogeneous protein preparations. So far, experimental studies have been limited in directly analyzing the earliest events of the conformational change of cellular prion protein (PrPC ) into scrapie prion protein (PrPSc ) that further propagates PrPC misfolding and aggregation at the cellular membrane, the initial site of prion infection, and PrP misfolding, by a lack of suitably modified PrP variants. PTMs of PrP, especially attachment of the glycosylphosphatidylinositol (GPI) anchor, have been shown to be crucially involved in the PrPSc formation. To this end, semisynthesis offers a unique possibility to understand PrP behavior invitro and invivo as it provides access to defined site-selectively modified PrP variants. This approach relies on the production and chemoselective linkage of peptide segments, amenable to chemical modifications, with recombinantly produced protein segments. In this article, advances in understanding PrP conversion using semisynthesis as a tool to obtain homogeneous posttranslationally modified PrP will be discussed.
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Affiliation(s)
- Stefanie Hackl
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Vienna, Austria
| | - Christian F W Becker
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Vienna, Austria
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Matveenko M, Hackl S, Becker CFW. Utility of the Phenacyl Protecting Group in Traceless Protein Semisynthesis through Ligation-Desulfurization Chemistry. ChemistryOpen 2018; 7:106-110. [PMID: 29321951 PMCID: PMC5759462 DOI: 10.1002/open.201700180] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/12/2017] [Indexed: 12/13/2022] Open
Abstract
Semisynthesis of proteins via expressed protein ligation is a widely applicable method, even more so because of the possibility of ligation at non-cysteine sites using β-mercapto amino acids that can be converted to the corresponding native amino acids by desulfurization. A drawback of this ligation- desulfurization approach is the removal of any unprotected native cysteine residues within the ligated protein segments. Here, we show that the phenacyl (PAc) moiety can be successfully used to protect cysteines within recombinantly generated protein segments. As such, this group was selectively appended onto cysteine side chains within bacterially expressed polypeptides following intein cleavage, which reveals a rather sensitive thioester at the C-terminus. The PAc group proved to be compatible with native chemical ligation, radical desulfurization, and reverse-phase HPLC conditions, and was smoothly removed at the end. The utility of the PAc protecting group was then demonstrated by the 'traceless' semisynthesis of two proteins containing one or two native cysteines: human small heat shock protein Hsp27 and murine prion protein.
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Affiliation(s)
- Maria Matveenko
- Institute of Biological Chemistry, Faculty of Chemistry University of Vienna Währinger Str. 38 1090 Vienna Austria
| | - Stefanie Hackl
- Institute of Biological Chemistry, Faculty of Chemistry University of Vienna Währinger Str. 38 1090 Vienna Austria
| | - Christian F W Becker
- Institute of Biological Chemistry, Faculty of Chemistry University of Vienna Währinger Str. 38 1090 Vienna Austria
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Araman C, Thompson RE, Wang S, Hackl S, Payne RJ, Becker CFW. Semisynthetic prion protein (PrP) variants carrying glycan mimics at position 181 and 197 do not form fibrils. Chem Sci 2017; 8:6626-6632. [PMID: 28989689 PMCID: PMC5625290 DOI: 10.1039/c7sc02719b] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 07/18/2017] [Indexed: 12/12/2022] Open
Abstract
Semisynthesis and characterization of homogeneously mono- and di-PEGylated full length PrP variants to study the impact of PEGylation (as N-glycan mimics) on protein folding and aggregation.
The prion protein (PrP) is an N-glycosylated protein attached to the outer leaflet of eukaryotic cell membranes via a glycosylphosphatidylinositol (GPI) anchor. Different prion strains have distinct glycosylation patterns and the extent of glycosylation of potentially pathogenic misfolded prion protein (PrPSc) has a major impact on several prion-related diseases (transmissible spongiform encephalopathies, TSEs). Based on these findings it is hypothesized that posttranslational modifications (PTMs) of PrP influence conversion of cellular prion protein (PrPC) into PrPSc and, as such, modified PrP variants are critical tools needed to investigate the impact of PTMs on the pathogenesis of TSEs. Here we report a semisynthetic approach to generate PrP variants modified with monodisperse polyethyleneglycol (PEG) units as mimics of N-glycans. Incorporating PEG at glycosylation sites 181 and 197 in PrP induced only small changes to the secondary structure when compared to unmodified, wildtype PrP. More importantly, in vitro aggregation was abrogated for all PEGylated PrP variants under conditions at which wildtype PrP aggregated. Furthermore, the addition of PEGylated PrP as low as 10 mol% to wildtype PrP completely blocked aggregation. A similar effect was observed for synthetic PEGylated PrP segments comprising amino acids 179–231 alone if these were added to wildtype PrP in aggregation assays. This behavior raises the question if large N-glycans interfere with aggregation in vivo and if PEGylated PrP peptides could serve as potential therapeutics.
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Affiliation(s)
- Can Araman
- Institute of Biological Chemistry , Department of Chemistry , University of Vienna , Waehringer Strasse 38 , 1090 , Vienna-AT , Austria .
| | - Robert E Thompson
- School of Chemistry , The University of Sydney , Sydney , NSW 2006 , Australia
| | - Siyao Wang
- School of Chemistry , The University of Sydney , Sydney , NSW 2006 , Australia
| | - Stefanie Hackl
- Institute of Biological Chemistry , Department of Chemistry , University of Vienna , Waehringer Strasse 38 , 1090 , Vienna-AT , Austria .
| | - Richard J Payne
- School of Chemistry , The University of Sydney , Sydney , NSW 2006 , Australia
| | - Christian F W Becker
- Institute of Biological Chemistry , Department of Chemistry , University of Vienna , Waehringer Strasse 38 , 1090 , Vienna-AT , Austria .
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Hackl S, Merkel P, Hungerer S, Friederichs J, Müller N, Militz M, Bühren V. [Pyoderma gangrenosum after intramedullary nailing of tibial shaft fracture: A differential diagnosis to necrotizing fasciitis]. Unfallchirurg 2016; 118:1062-6. [PMID: 25672810 DOI: 10.1007/s00113-015-2737-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pyoderma gangrenosum is a rare non-infectious neutrophilic dermatitis, whereas necrotizing fasciitis is a life-threatening bacterial soft tissue infection of the fascia and adjacent skin. As in the case described here after intramedullary nailing, the clinical appearance of both diseases can be similar. Because of the completely different therapeutic approach and a worse outcome in the case of false diagnosis, pyoderma gangrenosum should always be taken into consideration before treating necrotizing fasciitis.
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Affiliation(s)
- S Hackl
- BG Unfallklinik Murnau, Professor-Küntscher-Str. 8, 82418, Murnau, Deutschland.
| | - P Merkel
- BG Unfallklinik Murnau, Professor-Küntscher-Str. 8, 82418, Murnau, Deutschland
| | - S Hungerer
- BG Unfallklinik Murnau, Professor-Küntscher-Str. 8, 82418, Murnau, Deutschland
| | - J Friederichs
- BG Unfallklinik Murnau, Professor-Küntscher-Str. 8, 82418, Murnau, Deutschland
| | - N Müller
- Klinikum Kempten, Kempten, Deutschland
| | - M Militz
- BG Unfallklinik Murnau, Professor-Küntscher-Str. 8, 82418, Murnau, Deutschland
| | - V Bühren
- BG Unfallklinik Murnau, Professor-Küntscher-Str. 8, 82418, Murnau, Deutschland
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Abstract
The site-selective installation of lipid modifications on proteins is critically important in our understanding of how membrane association influences the biophysical properties of proteins as well as to study certain proteins in their native environment. Here, we describe the use of split inteins for the C-terminal attachment of lipid-modified peptides to virtually any protein of interest (POI) via protein trans-splicing (PTS). To achieve this, the protein of interest is expressed in fusion with the N-terminal split intein segment and the C-terminal split intein segment is prepared by solid phase peptide synthesis. A synthetic peptide carrying two lipid chains is also made chemically to serve as a membrane anchor and subsequently linked to the C-terminal split intein by native chemical ligation. Proteins of interest for our work are the prion protein as well as small GTPases; however, extensions to other POIs are possible. Detailed information for the C-terminal introduction of a lipidated membrane anchor (MA) peptide using split intein systems from Synechocystis spp. and Nostoc punctiforme for the Prion protein (PrP, as a challenging protein of interest) and the enhanced green-fluorescent protein (eGFP, as an easily trackable target protein) are provided here.
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Affiliation(s)
- Stefanie Hackl
- Department of Chemistry, Institute of Biological Chemistry, University of Vienna, Waehringer Str. 38, 1090, Vienna, Austria
| | - Alanca Schmid
- Department of Chemistry, Institute of Biological Chemistry, University of Vienna, Waehringer Str. 38, 1090, Vienna, Austria
| | - Christian F W Becker
- Department of Chemistry, Institute of Biological Chemistry, University of Vienna, Waehringer Str. 38, 1090, Vienna, Austria.
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Zhu XM, Hackl S, Thaker MN, Kalan L, Weber C, Urgast DS, Krupp EM, Brewer A, Vanner S, Szawiola A, Yim G, Feldmann J, Bechthold A, Wright GD, Zechel DL. Biosynthesis of the Fluorinated Natural Product Nucleocidin inStreptomyces calvusIs Dependent on thebldA-Specified Leu-tRNAUUAMolecule. Chembiochem 2015; 16:2498-506. [DOI: 10.1002/cbic.201500402] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Xi Ming Zhu
- Department of Chemistry; Queen's University; Chernoff Hall 90 Bader Lane Kingston Ontario K7L 3N6 Canada
| | - Stefanie Hackl
- Department of Pharmaceutical Biology and Biotechnology; Institute of Pharmaceutical Sciences; Albert-Ludwigs-Universität Freiburg; Stefan-Meier-Strasse 19 79104 Freiburg Germany
| | - Maulik N. Thaker
- Michael G. DeGroote Institute for Infectious Disease Research; McMaster University; 1200 Main Street West Hamilton Ontario L8N 3Z5 Canada
| | - Lindsay Kalan
- Michael G. DeGroote Institute for Infectious Disease Research; McMaster University; 1200 Main Street West Hamilton Ontario L8N 3Z5 Canada
| | - Claudia Weber
- Trace Element Speciation Laboratory; Department of Chemistry; University of Aberdeen; Aberdeen AB24 3UE UK
| | - Dagmar S. Urgast
- Trace Element Speciation Laboratory; Department of Chemistry; University of Aberdeen; Aberdeen AB24 3UE UK
| | - Eva M. Krupp
- Trace Element Speciation Laboratory; Department of Chemistry; University of Aberdeen; Aberdeen AB24 3UE UK
| | - Alyssa Brewer
- Department of Chemistry; Queen's University; Chernoff Hall 90 Bader Lane Kingston Ontario K7L 3N6 Canada
| | - Stephanie Vanner
- Department of Chemistry; Queen's University; Chernoff Hall 90 Bader Lane Kingston Ontario K7L 3N6 Canada
| | - Anjuli Szawiola
- Department of Chemistry; Queen's University; Chernoff Hall 90 Bader Lane Kingston Ontario K7L 3N6 Canada
| | - Grace Yim
- Michael G. DeGroote Institute for Infectious Disease Research; McMaster University; 1200 Main Street West Hamilton Ontario L8N 3Z5 Canada
| | - Jörg Feldmann
- Trace Element Speciation Laboratory; Department of Chemistry; University of Aberdeen; Aberdeen AB24 3UE UK
| | - Andreas Bechthold
- Department of Pharmaceutical Biology and Biotechnology; Institute of Pharmaceutical Sciences; Albert-Ludwigs-Universität Freiburg; Stefan-Meier-Strasse 19 79104 Freiburg Germany
| | - Gerard D. Wright
- Michael G. DeGroote Institute for Infectious Disease Research; McMaster University; 1200 Main Street West Hamilton Ontario L8N 3Z5 Canada
| | - David L. Zechel
- Department of Chemistry; Queen's University; Chernoff Hall 90 Bader Lane Kingston Ontario K7L 3N6 Canada
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Arens D, Wilke M, Calabro L, Hackl S, Zeiter S, Zderic I, Richards RG, Moriarty TF, Moriarty TF. A rabbit humerus model of plating and nailing osteosynthesis with and without Staphylococcus aureus osteomyelitis. Eur Cell Mater 2015; 30:148-61; discussion 161-2. [PMID: 26388617 DOI: 10.22203/ecm.v030a11] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The local mechanical environment at a fracture is known to influence biological factors such as callus formation, immune cell recruitment and susceptibility to infection. Infection models incorporating a fracture are therefore required to evaluate prevention and treatment of infection after osteosynthesis. The aim of this study was to create humane, standardised and repeatable preclinical models of implant-related bone infection after osteosynthesis in the rabbit humerus. Custom-designed interlocked intramedullary nails and commercially available locking plates were subjected to biomechanical evaluation in cadaveric rabbit humeri; a 10-week in vivo healing study; a dose response study with Staphylococcus aureus over 4 weeks; and finally, a long-term infection of 10 weeks in the plate model.Outcome measures included biomechanical testing, radiography, histology, haematology and quantitative bacteriology. Both implants offered similar biomechanical stability in cadaveric bones, and when applied in the in vivo study, resulted in complete radiographic and histological healing and osteotomy closure within 10-weeks. As expected in the infection study, higher bacterial doses led to an increasing infection rate. In both infected groups, there was a complete lack of osteotomy closure at 4 weeks. C-reactive protein (CRP), lymphocyte: granulocyte ratio and weight loss were increased in infected animals receiving IM nails in comparison with non-inoculated equivalents, although this was less evident in the plate group. In the 10-week infection group, healing does not occur in the plated rabbits. We have successfully developed a rabbit model that is suitable for further studies, particularly those looking into preventative strategies for post-traumatic implant-related osteomyelitis.
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Affiliation(s)
- D Arens
- AO Research Institute Davos, AO Foundation, Clavadelerstrasse 8, CH 7270 Davos Platz,
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von Rüden C, Hackl S, Woltmann A, Friederichs J, Bühren V, Hierholzer C. [The Postero-Lateral Approach--An Alternative to Closed Anterior-Posterior Screw Fixation of a Dislocated Postero-Lateral Fragment of the Distal Tibia in Complex Ankle Fractures]. Z Orthop Unfall 2015; 153:289-95. [PMID: 25959570 DOI: 10.1055/s-0035-1545706] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND The dislocated posterolateral fragment of the distal tibia is considered as a key fragment for the successful reduction of comminuted ankle fractures. The reduction of this fragment can either be achieved indirectly by joint reduction using the technique of closed anterior-posterior screw fixation, or directly using the open posterolateral approach followed by plate fixation. The aim of this study was to compare the outcome after stabilization of the dislocated posterolateral tibia fragment using either closed reduction and screw fixation, or open reduction and plate fixation via the posterolateral approach in complex ankle fractures. PATIENTS/MATERIAL AND METHODS In a prospective study between 01/2010 and 12/2012, all mono-injured patients with closed ankle fractures and dislocated posterolateral tibia fragments were assessed 12 months after osteosynthesis. Parameters included: size of the posterolateral tibia fragment relative to the tibial joint surface (CT scan, in %) as an indicator of injury severity, unreduced area of tibial joint surface postoperatively, treatment outcome assessed by using the "Ankle Fracture Scoring System" (AFSS), as well as epidemiological data and duration of the initial hospital treatment. RESULTS In 11 patients (10 female, 1 male; age 51.6 ± 2.6 years [mean ± SEM], size of tibia fragment 42.1 ± 2.5 %) the fragment fixation was performed using a posterolateral approach. Impaired postoperative wound healing occurred in 2 patients of this group. In the comparison group, 12 patients were treated using the technique of closed anterior-posterior screw fixation (10 female, 2 male; age 59.5 ± 6.7 years, size of tibia fragment 45.9 ± 1.5 %). One patient of this group suffered an incomplete lesion of the superficial peroneal nerve. Radiological evaluation of the joint surface using CT scan imaging demonstrated significantly less dislocation of the tibial joint surface following the open posterolateral approach (0.60 ± 0.20 mm) compared to the closed anterior-posterior screw fixation (1.03 ± 0.08 mm; p < 0.05). Assessment of the treatment outcome using the AFSS demonstrated a significantly higher score of 97.4 ± 6.4 in the group with a posterolateral approach compared to a score of 74.4 ± 12.1 (p < 0.05) in the group with an anterior-posterior screw fixation. CONCLUSION In comparison to the anterior-posterior screw fixation, open reduction and fixation of the dislocated, posterolateral key fragment of the distal tibia using a posterolateral approach resulted in a more accurate fracture reduction and significantly better functional outcome 12 months after surgery. In addition, no increased rate of postoperative complications, or extended hospital stay was observed but there was less severe post-traumatic joint arthritis. The results of this study suggest that in complex ankle factures the open fixation of the dislocated posterolateral fragment is recommended as an alternative surgical procedure and may be beneficial for both clinical and radiological long-term outcomes.
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Affiliation(s)
- C von Rüden
- Abteilung Unfallchirurgie, Berufsgenossenschaftliche Unfallklinik Murnau
| | - S Hackl
- Abteilung Unfallchirurgie, Berufsgenossenschaftliche Unfallklinik Murnau
| | - A Woltmann
- Abteilung Unfallchirurgie, Berufsgenossenschaftliche Unfallklinik Murnau
| | - J Friederichs
- Abteilung Unfallchirurgie, Berufsgenossenschaftliche Unfallklinik Murnau
| | - V Bühren
- Abteilung Unfallchirurgie, Berufsgenossenschaftliche Unfallklinik Murnau
| | - C Hierholzer
- Abteilung Unfallchirurgie, Berufsgenossenschaftliche Unfallklinik Murnau
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Hackl S, Bechthold A. The GenebldA, a Regulator of Morphological Differentiation and Antibiotic Production inStreptomyces. Arch Pharm (Weinheim) 2015; 348:455-62. [DOI: 10.1002/ardp.201500073] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 03/23/2015] [Accepted: 03/24/2015] [Indexed: 01/24/2023]
Affiliation(s)
- Stefanie Hackl
- Department of Pharmaceutical Biology and Biotechnology; Institute of Pharmaceutical Sciences; Albert-Ludwig University of Freiburg; Freiburg Germany
| | - Andreas Bechthold
- Department of Pharmaceutical Biology and Biotechnology; Institute of Pharmaceutical Sciences; Albert-Ludwig University of Freiburg; Freiburg Germany
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Filak LK, Göschl S, Hackl S, Jakupec MA, Arion VB. Ruthenium- and osmium-arene complexes of 8-substituted indolo[3,2- c]quinolines: Synthesis, X-ray diffraction structures, spectroscopic properties, and antiproliferative activity. Inorganica Chim Acta 2012; 393:252-260. [PMID: 23471093 PMCID: PMC3587412 DOI: 10.1016/j.ica.2012.06.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Six novel ruthenium(II)- and osmium(II)-arene complexes with indoloquinoline modified ligands containing methyl and halo substituents in position 8 of the molecule backbone have been synthesised and comprehensively characterised by spectroscopic methods (1H, 13C NMR, UV-Vis), ESI mass spectrometry and X-ray crystallography. Binding of indoloquinolines to a metal-arene scaffold makes the products soluble enough in biological media to allow for assaying their antiproliferative activity. The complexes were tested in three human cancer cell lines, namely A549 (non-small cell lung cancer), SW480 (colon carcinoma) and CH1 (ovarian carcinoma), yielding IC50 values in the 10-6-10-7 M concentration range after continuous exposure for 96 h. Compounds with halo substituents in position 8 are more effective cytotoxic agents in vitro than the previously reported species halogenated in position 2 of the indoloquinoline backbone. High antiproliferative activity of both series of substances may be due at least in part to their potential to act as DNA intercalators.
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Affiliation(s)
| | | | | | | | - Vladimir B. Arion
- Institute of Inorganic Chemistry, University of Vienna, Währinger Strasse 42, 1090 Vienna, Austria
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13
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van den Hoven R, Bauer A, Hackl S, Zickl M, Spona J, Zentek J. A preliminary study on the changes in some potential markers of muscle-cell degradation in sub-maximally exercised horses supplemented with a protein and amino acid mixture. J Anim Physiol Anim Nutr (Berl) 2010; 95:664-75. [PMID: 21121963 DOI: 10.1111/j.1439-0396.2010.01097.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this preliminary study, time-dependent changes in plasma CK and AST activity, tyrosine (Tyr), 3-methyl-histidine (3mHis), glucose and lactate concentrations were analysed in nine horses under two different conditions. Furthermore, intramuscular concentrations of Tyr, 3mHis and activities of cathepsin B, acid phosphatase (ACP), glucose-6-phosphate dehydrogenase (G6PDH) and mRNA expression of ubiquitin were determined at the same time. After studying the effects of exercise alone, the effects of exercise and feeding of an experimental protein/amino acid (AA) supplement were analysed. Horses were submitted to a total of four standardised exercise tests (SETs) of high intensity. Potential markers of muscle break down were determined prior to, immediately after, 4 and 18 h after exercise. The experiment was subdivided into two consecutive periods of 3 weeks. In each period, two SETs were performed. In the second period, horses were fed with the protein/AA supplement within 1 h after exercise. Significant changes in plasma, intramuscular Tyr levels and mRNA expression of ubiquitin were caused both by time in relation to exercise and by treatment with the protein/AA supplement. The experimental supplement significantly decreased the 4-h post-exercise expression of ubiquitin mRNA in muscle. Only a borderline increase of markers of lysosomal involvement was seen and CK and AST activity generally showed their normal post-exercise patterns. A clear post-exercise reduction of this CK activity, however, was not observed after supplementation with the protein/AA mixture. The current findings indicate that horses might benefit from protein and AA supplementation directly after training by decreasing post-exercise proteolysis. The results support that further studies should be performed to characterize changes in equine protein metabolism caused by exercise including underlying molecular mechanisms.
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Affiliation(s)
- R van den Hoven
- Clinic of Internal Medicine and Clinical Epidemiology of Equids, Clinical Department of Companion Animals and Horses, Institute of Animal Nutrition, Veterinary University of Vienna, Vienna, Austria.
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van den Hoven R, Bauer A, Hackl S, Zickl M, Spona J, Zentek J. Changes in intramuscular amino acid levels in submaximally exercised horses - a pilot study. J Anim Physiol Anim Nutr (Berl) 2010; 94:455-64. [PMID: 19663973 DOI: 10.1111/j.1439-0396.2009.00929.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The time-dependent changes in intramuscular amino acid (AA) levels caused by exercise and by feeding a protein/AA supplement were analysed in nine horses. Horses were submitted to a total of four standardized exercise tests (SETs). Amino acid concentrations were determined prior to, immediately after, 4 and 18 h after exercise. The experiment was subdivided into two consecutive periods of 3 weeks. In each period two SETs were performed. In the second period, horses were given a protein/AA supplement within 1 h after exercise. Significant changes in mean plasma AA levels similar to previous studies were noted to be time-dependent and to be associated with feeding the supplement. The intramuscular concentrations of the free AA in relation to pre-exercise levels showed significant time-dependent changes for alanine, asparagine, aspartate, citrulline, glutamine, glycine, isoleucine, leucine, methionine, serine, taurine, threonine, tyrosine and valine. Feeding the supplement significantly increased the 4 h post-exercise intramuscular concentration of alanine, isoleucine, methionine and tyrosine. At 18 h after exercise, apart from isoleucine and methionine, levels were still increased and also those of asparagine, histidine and valine in relation to none treatment. Hence, it was concluded that AA mixtures administered orally to horses within 1 h after exercise increased intramuscular AA pool.
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Affiliation(s)
- R van den Hoven
- Clinical Department for Companion Animals and Horses, Clinic of Internal Medicine and Clinical Epidemiology of Equids, Veterinary University of Vienna, Vienna, Austria.
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Hackl S, van den Hoven R, Zickl M, Spona J, Zentek J. The effects of short intensive exercise on plasma free amino acids in standardbred trotters. J Anim Physiol Anim Nutr (Berl) 2009; 93:165-73. [DOI: 10.1111/j.1439-0396.2007.00801.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hackl S, van den Hoven R, Zickl M, Spona J, Zentek J. Individual Differences and Repeatability of Post-prandial Changes of Plasma-free Amino Acids in Young Horses. ACTA ACUST UNITED AC 2006; 53:439-44. [PMID: 17054477 DOI: 10.1111/j.1439-0442.2006.00862.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Few data are available on post-prandial changes of plasma amino acids (AAs) in horses and on the repeatability and the individual variance on different sampling days. The objective of the present study was to measure pre- and post-prandial concentrations of plasma AA in 10 yearling horses. Blood samples were taken on days 1 and 40 of the study before feeding of hay, oats and soya meal and over an 8 h post-prandial period in 2-h intervals. The plasma AAs were measured by high-pressure liquid chromatography after ortho-phthalaldehyde derivatization. Mean fasting concentrations of the AAs were not significantly influenced by the individuum and sampling day. Repeatability of the fasting AA levels in the individual horses on two different sampling days was only found for histidine, 3-methylhistidine, methionine, tryptophan and taurine. While the absolute post-prandial AA concentrations differed between sampling days, the relative changes were comparable. All AA concentrations except 3-methylhistidine increased after feeding by 13% to more than 200% of their fasting values if the combined data of both days were analysed. Four hours after feeding the concentrations of arginine, asparagine, lysine, leucine, isoleucine and threonine, decreased more than 20%. Histidine, methionine, phenylalanine, valine, tryptophan, glutamine, glycine, tyrosine and taurine concentrations decreased by less than 20%. Concentrations of aspartic acid, glutamic acid, ornithine, serine and citrulline remained elevated. Most AA approached the fasting concentrations at 8 h, only glycine increased between 6 and 8 h after meal and 3-methyl-histidine concentrations were constant throughout the entire period. In conclusion, the pre-prandial plasma AA in horses appeared less influenced by individuum or sampling day than post-prandial plasma AA concentrations. Therefore, plasma AA concentrations should be interpreted only under well-defined conditions, especially regarding the feeding regimen.
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Affiliation(s)
- S Hackl
- Department of Veterinary Public Health, Institute of Nutrition, University of Veterinary Medicine, Vienna, Austria
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Groh C, Hackl S, Tatzer E, Groh V. [Psychosocial influences on the success of therapy in epileptic children (author's transl)]. Fortschr Neurol Psychiatr Grenzgeb 1980; 48:603-11. [PMID: 6903550 DOI: 10.1055/s-2007-1002403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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