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Satoshi Murakami - One of the best experts on this subject based on the ideXlab platform.
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crystal structure of tripartite type abc transporter macb from acinetobacter baumannii
Nature Communications, 2017Co-Authors: Ui Okada, Hendrik W. Van Veen, Arthur Neuberger, Eiki Yamashita, Mayu Morimoto, Satoshi MurakamiAbstract:The MacA-MacB-TolC tripartite complex is a transmembrane machine that spans both plasma membrane and outer membrane and actively extrudes substrates, including macrolide antibiotics, virulence factors, peptides and cell envelope precursors. These transport activities are driven by the ATPase MacB, a member of the ATP-binding cassette (ABC) superfamily. Here, we present the crystal structure of MacB at 3.4-A resolution. MacB forms a dimer in which each protomer contains a nucleotide-binding domain and four transmembrane helices that protrude in the periplasm into a binding domain for interaction with the membrane fusion protein MacA. MacB represents an ABC transporter in pathogenic microorganisms with unique structural features.
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structure of the macab tolc abc type tripartite multidrug efflux pump
Nature microbiology, 2017Co-Authors: A W P Fitzpatrick, Salome Llabres, Arthur Neuberger, James N Blaza, Ui Okada, Satoshi Murakami, Hendrik W Van Veen, Ulrich Zachariae, Sjors H W Scheres, Ben F LuisiAbstract:The MacA–MacB–TolC assembly of Escherichia coli is a transmembrane machine that spans the cell envelope and actively extrudes substrates, including macrolide antibiotics and polypeptide virulence factors. These transport processes are energized by the ATPase MacB, a member of the ATP-binding cassette (ABC) superfamily. We present an electron cryo-microscopy structure of the ABC-type tripartite assembly at near-atomic resolution. A hexamer of the periplasmic protein MacA bridges between a TolC trimer in the outer membrane and a MacB dimer in the inner membrane, generating a quaternary structure with a central channel for substrate translocation. A gating ring found in MacA is proposed to act as a one-way valve in substrate transport. The MacB structure features an atypical transmembrane domain with a closely packed dimer interface and a periplasmic opening that is the likely portal for substrate entry from the periplasm, with subsequent displacement through an allosteric transport mechanism. Cryo-electron microscopy of the tripartite MacA–MacB–TolC multidrug transporter.
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structure of the macab tolc abc type tripartite multidrug efflux pump
Nature microbiology, 2017Co-Authors: A W P Fitzpatrick, Hendrik W. Van Veen, Salome Llabres, Arthur Neuberger, James N Blaza, Ui Okada, Satoshi Murakami, Ulrich Zachariae, Xiao Chen Bai, Sjors H W ScheresAbstract:The MacA-MacB-TolC assembly of Escherichia coli is a transmembrane machine that spans the cell envelope and actively extrudes substrates, including macrolide antibiotics and polypeptide virulence factors. These transport processes are energized by the ATPase MacB, a member of the ATP-binding cassette (ABC) superfamily. We present an electron cryo-microscopy structure of the ABC-type tripartite assembly at near-atomic resolution. A hexamer of the periplasmic protein MacA bridges between a TolC trimer in the outer membrane and a MacB dimer in the inner membrane, generating a quaternary structure with a central channel for substrate translocation. A gating ring found in MacA is proposed to act as a one-way valve in substrate transport. The MacB structure features an atypical transmembrane domain with a closely packed dimer interface and a periplasmic opening that is the likely portal for substrate entry from the periplasm, with subsequent displacement through an allosteric transport mechanism.
Nicola Maffulli - One of the best experts on this subject based on the ideXlab platform.
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arthroscopy versus mini arthrotomy approach for matrix induced autologous chondrocyte implantation in the knee a systematic review
Journal of Orthopaedics and Traumatology, 2021Co-Authors: Filippo Migliorini, Jorg Eschweiler, Filippo Spiezia, Bryan J M Van De Wall, Matthias Knobe, Markus Tingart, Nicola MaffulliAbstract:Matrix-induced autologous chondrocyte implantation (MACI) can be performed in a full arthroscopic or mini-open fashion. A systematic review was conducted to investigate whether arthroscopy provides better surgical outcomes compared with the mini-open approach for MACI in the knee at midterm follow-up. This systematic review was conducted following the PRISMA guidelines. The literature search was performed in May 2021. All the prospective studies reporting outcomes after MACI chondral defects of the knee were accessed. Only studies that clearly stated the surgical approach (arthroscopic or mini-open) were included. Only studies reporting a follow-up longer than 12 months were eligible. Studies reporting data from combined surgeries were not eligible, nor were those combining MACI with less committed cells (e.g., mesenchymal stem cells). Sixteen studies were included, and 770 patients were retrieved: 421 in the arthroscopy group, 349 in the mini-open. The mean follow-up was 44.3 (12–60) months. No difference between the two groups was found in terms of mean duration of symptoms, age, body mass index (BMI), gender, defect size (P > 0.1). No difference was found in terms of Tegner Score (P = 0.3), Lysholm Score (P = 0.2), and International Knee Documentation Committee (IKDC) Score (P = 0.1). No difference was found in the rate of failures (P = 0.2) and revisions (P = 0.06). Arthroscopy and mini-arthrotomy approaches for MACI in knee achieve similar outcomes at midterm follow-up. II, systematic review of prospective studies.
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Arthroscopy versus mini-arthrotomy approach for matrix-induced autologous chondrocyte implantation in the knee: a systematic review
'Springer Science and Business Media LLC', 2021Co-Authors: Filippo Migliorini, Jorg Eschweiler, Filippo Spiezia, Bryan J M Van De Wall, Matthias Knobe, Markus Tingart, Nicola MaffulliAbstract:Abstract Background Matrix-induced autologous chondrocyte implantation (MACI) can be performed in a full arthroscopic or mini-open fashion. A systematic review was conducted to investigate whether arthroscopy provides better surgical outcomes compared with the mini-open approach for MACI in the knee at midterm follow-up. Methods This systematic review was conducted following the PRISMA guidelines. The literature search was performed in May 2021. All the prospective studies reporting outcomes after MACI chondral defects of the knee were accessed. Only studies that clearly stated the surgical approach (arthroscopic or mini-open) were included. Only studies reporting a follow-up longer than 12 months were eligible. Studies reporting data from combined surgeries were not eligible, nor were those combining MACI with less committed cells (e.g., mesenchymal stem cells). Results Sixteen studies were included, and 770 patients were retrieved: 421 in the arthroscopy group, 349 in the mini-open. The mean follow-up was 44.3 (12–60) months. No difference between the two groups was found in terms of mean duration of symptoms, age, body mass index (BMI), gender, defect size (P > 0.1). No difference was found in terms of Tegner Score (P = 0.3), Lysholm Score (P = 0.2), and International Knee Documentation Committee (IKDC) Score (P = 0.1). No difference was found in the rate of failures (P = 0.2) and revisions (P = 0.06). Conclusion Arthroscopy and mini-arthrotomy approaches for MACI in knee achieve similar outcomes at midterm follow-up. Level of evidence II, systematic review of prospective studies
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Surgical management of focal chondral defects of the knee: a Bayesian network meta-analysis
'Springer Science and Business Media LLC', 2021Co-Authors: Filippo Migliorini, Jorg Eschweiler, Markus Tingart, Hanno Schenker, Alice Baroncini, Nicola MaffulliAbstract:Abstract Background Focal chondral defects of the knee are common. Several surgical techniques have been proposed for the management of chondral defects: microfractures (MFX), osteochondral autograft transplantation (OAT), autologous matrix-induced chondrogenesis (AMIC) and autologous chondrocyte implantation (ACI)—first generation (pACI), second generation (cACI) and third generation (MACI). A Bayesian network meta-analysis was conducted to compare these surgical strategies for chondral defects in knee at midterm follow-up. Methods This Bayesian network meta-analysis was conducted according to the PRISMA extension statement for reporting of systematic reviews incorporating network meta-analyses of health care interventions. PubMed, Google Scholar, Embase and Scopus databases were accessed in July 2021. All the prospective comparative clinical trials investigating two or more surgical interventions for chondral defects of the knee were accessed. The network meta-analyses were performed through a Bayesian hierarchical random-effects model analysis. The log odds ratio (LOR) effect measures were used for dichotomic variables, while the standardized mean difference (SMD) for the continuous variables. Results Data from 2220 procedures (36 articles) were retrieved. The median follow-up was 36 (24 to 60) months. The ANOVA test found good baseline comparability between symptoms duration, age, sex and body mass index. AMIC resulted in higher Lysholm score (SMD 3.97) and Tegner score (SMD 2.10). AMIC demonstrated the lowest rate of failures (LOR −0.22) and the lowest rate of revisions (LOR 0.89). As expected, MFX reported the lower rate of hypertrophy (LOR −0.17) followed by AMIC (LOR 0.21). No statistically significant inconsistency was found in the comparisons. Conclusion AMIC procedure for focal chondral defects of the knee performed better overall at approximately 3 years’ follow-up
David Wood - One of the best experts on this subject based on the ideXlab platform.
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association between isokinetic knee strength and perceived function and patient satisfaction with sports and recreational ability after matrix induced autologous chondrocyte implantation
Orthopaedic Journal of Sports Medicine, 2019Co-Authors: Jay R Ebert, Anne Smith, Gregory C Janes, David WoodAbstract:Background:Returning to a sound level of activity after matrix-induced autologous chondrocyte implantation (MACI) is important to patients. Evaluating the patient’s level of satisfaction with his o...
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incidence degree and development of graft hypertrophy 24 months after matrix induced autologous chondrocyte implantation association with clinical outcomes
American Journal of Sports Medicine, 2015Co-Authors: Jay R Ebert, Michael Fallon, Anne Smith, Rodney Butler, Robert Nairn, William Breidahl, David WoodAbstract:Background:Graft hypertrophy is a common occurrence after periosteal, collagen-covered and matrix-induced autologous chondrocyte implantation (MACI).Purpose/Hypothesis:The purpose of this study was to investigate the incidence, development, and degree of graft hypertrophy at 24 months after MACI. The hypothesis was that graft hypertrophy would not be associated with clinical outcome at 24 months.Study Design:Case series, Level of evidence, 4.Methods:This study was undertaken in 180 consecutive patients (113 male, 67 female) after MACI in the knee. All patients were assessed clinically using the Knee injury and Osteoarthritis Outcome Score (KOOS) and underwent magnetic resonance imaging (MRI) at 3, 12, and 24 months after surgery. The incidence of hypertrophy relevant to anatomic graft site was investigated, as was the progressive change in hypertrophic studies postoperatively. The degree of tissue overgrowth in hypertrophic cases was investigated, as was its association with patient clinical outcome at 24...
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a randomized trial comparing accelerated and traditional approaches to postoperative weightbearing rehabilitation after matrix induced autologous chondrocyte implantation findings at 5 years
American Journal of Sports Medicine, 2012Co-Authors: Jay R Ebert, Michael Fallon, M H Zheng, David Wood, Tim AcklandAbstract:Background:While structured postoperative rehabilitation after matrix-induced autologous chondrocyte implantation (MACI) is considered critical, very little has been made available on how best to progressively increase weightbearing and exercise after surgery.Hypothesis:A significant improvement will exist in clinical and magnetic resonance imaging (MRI)–based scoring measures to 5 years after surgery. Furthermore, there will be no significant differences in outcomes in MACI patients at 5 years when comparing a traditional and an accelerated postoperative weightbearing regimen. Finally, patient demographics, cartilage defect parameters, and injury/surgery history will be associated with graft outcome.Study Design:Randomized controlled trial; Level of evidence, 1.Methods:Clinical and radiological outcomes were studied in 70 patients who underwent MACI to the medial or lateral femoral condyle, in conjunction with either an “accelerated” or a “traditional” approach to postoperative weightbearing rehabilitati...
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clinical and magnetic resonance imaging based outcomes to 5 years after matrix induced autologous chondrocyte implantation to address articular cartilage defects in the knee
American Journal of Sports Medicine, 2011Co-Authors: Jay R Ebert, W B Robertson, Jennifer Woodhouse, Michael Fallon, M H Zheng, Tim Ackland, David WoodAbstract:Background: The availability remains limited of midterm clinical and radiologic results into matrix-induced autologous chondrocyte implantation (MACI). Outcomes are required to validate the efficacy of MACI as a suitable surgical treatment option for articular cartilage defects in the knee.Hypothesis: A significant improvement in clinical and magnetic resonance imaging–based (MRI-based) outcomes after MACI will exist throughout the postoperative timeline to 5 years after surgery. Furthermore, patient demographics, cartilage defect parameters, and injury/surgery history will be associated with patient and graft outcome, whereas a significant correlation will exist between clinical and MRI-based outcomes at 5 years after surgery.Study Design: Case series; Level of evidence, 4.Methods: A prospective evaluation was undertaken to assess clinical and MRI-based outcomes to 5 years in 41 patients (53 grafts) after MACI to the knee. After MACI surgery and a 12-week structured rehabilitation program, patients under...
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matrix induced autologous chondrocyte implantation MACI biological and histological assessment
Tissue Engineering, 2007Co-Authors: Minghao Zheng, David Wood, Craig Willers, Lyn Kirilak, Piers Yates, Jiake Xu, Andrew ShimminAbstract:Matrix-induced autologous chondrocyte implantation (MACI®) has been a treatment of cartilage injury since 2000, but little is known of the histological paradigm of tissue regeneration after implantation. MACI is a stable cell-based delivery system that enables the regeneration of hyaline-like cartilage. From a cohort of 56 MACI patients, we examined the phenotype of chondrocytes seeded on type I/III collagen scaffold, and conducted progressive histologic assessment over a period of 6 months. Chondrocyte-seeded collagen scaffolds from patient implants were analyzed by electron microscopy, immunohistochemistry (type II collagen and S-100), and reverse transcription polymerase chain reaction (RT-PCR) (aggrecan and type II collagen). Coincidental cartilage biopsies were obtained at 48 hours, 21 days, 6 months, 8 months, 12 months, 18 months, and 24 months. Our data showed that chondrocytes on the collagen scaffold appeared spherical, well integrated into the matrix, and maintained the chondrocyte phenotype as...
Ui Okada - One of the best experts on this subject based on the ideXlab platform.
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crystal structure of tripartite type abc transporter macb from acinetobacter baumannii
Nature Communications, 2017Co-Authors: Ui Okada, Hendrik W. Van Veen, Arthur Neuberger, Eiki Yamashita, Mayu Morimoto, Satoshi MurakamiAbstract:The MacA-MacB-TolC tripartite complex is a transmembrane machine that spans both plasma membrane and outer membrane and actively extrudes substrates, including macrolide antibiotics, virulence factors, peptides and cell envelope precursors. These transport activities are driven by the ATPase MacB, a member of the ATP-binding cassette (ABC) superfamily. Here, we present the crystal structure of MacB at 3.4-A resolution. MacB forms a dimer in which each protomer contains a nucleotide-binding domain and four transmembrane helices that protrude in the periplasm into a binding domain for interaction with the membrane fusion protein MacA. MacB represents an ABC transporter in pathogenic microorganisms with unique structural features.
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structure of the macab tolc abc type tripartite multidrug efflux pump
Nature microbiology, 2017Co-Authors: A W P Fitzpatrick, Salome Llabres, Arthur Neuberger, James N Blaza, Ui Okada, Satoshi Murakami, Hendrik W Van Veen, Ulrich Zachariae, Sjors H W Scheres, Ben F LuisiAbstract:The MacA–MacB–TolC assembly of Escherichia coli is a transmembrane machine that spans the cell envelope and actively extrudes substrates, including macrolide antibiotics and polypeptide virulence factors. These transport processes are energized by the ATPase MacB, a member of the ATP-binding cassette (ABC) superfamily. We present an electron cryo-microscopy structure of the ABC-type tripartite assembly at near-atomic resolution. A hexamer of the periplasmic protein MacA bridges between a TolC trimer in the outer membrane and a MacB dimer in the inner membrane, generating a quaternary structure with a central channel for substrate translocation. A gating ring found in MacA is proposed to act as a one-way valve in substrate transport. The MacB structure features an atypical transmembrane domain with a closely packed dimer interface and a periplasmic opening that is the likely portal for substrate entry from the periplasm, with subsequent displacement through an allosteric transport mechanism. Cryo-electron microscopy of the tripartite MacA–MacB–TolC multidrug transporter.
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structure of the macab tolc abc type tripartite multidrug efflux pump
Nature microbiology, 2017Co-Authors: A W P Fitzpatrick, Hendrik W. Van Veen, Salome Llabres, Arthur Neuberger, James N Blaza, Ui Okada, Satoshi Murakami, Ulrich Zachariae, Xiao Chen Bai, Sjors H W ScheresAbstract:The MacA-MacB-TolC assembly of Escherichia coli is a transmembrane machine that spans the cell envelope and actively extrudes substrates, including macrolide antibiotics and polypeptide virulence factors. These transport processes are energized by the ATPase MacB, a member of the ATP-binding cassette (ABC) superfamily. We present an electron cryo-microscopy structure of the ABC-type tripartite assembly at near-atomic resolution. A hexamer of the periplasmic protein MacA bridges between a TolC trimer in the outer membrane and a MacB dimer in the inner membrane, generating a quaternary structure with a central channel for substrate translocation. A gating ring found in MacA is proposed to act as a one-way valve in substrate transport. The MacB structure features an atypical transmembrane domain with a closely packed dimer interface and a periplasmic opening that is the likely portal for substrate entry from the periplasm, with subsequent displacement through an allosteric transport mechanism.
Marti Russlies - One of the best experts on this subject based on the ideXlab platform.
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matrix associated autologous chondrocyte transplantation implantation mact MACI 5 year follow up
Knee, 2006Co-Authors: Pete Ehrens, Thomas Itte, Odo Kurz, Marti RussliesAbstract:Matrix-associated autologous chondrocyte transplantation/implantation (MACT/MACI) is a new operation procedure using a cell seeded collagen matrix for the treatment of localized full-thickness cartilage defects. A prospective clinical investigation was carried out in order to clarify whether this proves suitable and confirms objective and subjective clinical improvement over a period of up to 5 years after operation. Thirty-eight patients with localised cartilage defects were treated with MACT. Within the context of clinical follow-up, these patients were evaluated for up to 5 years after the intervention. Four different scores (Meyers score, Tegner-Lysholm activity score, Lysholm-Gillquist score, ICRS score) as well as the results of six arthroscopies and biopsies obtained from four patients formed the basis of this study. For 15 patients, 5 or more years had elapsed since the operation at the time this study was completed. It was possible to obtain results 5 years postoperatively from 11 (73.3%) of these 15 patients. Overall, we included 25 patients into the evaluation with a 2-year or longer postoperative period. Five years after transplantation 8 out of 11 patients rated the function of their knee as much better or better than before. Three of the four scores showed significant improvement compared to the preoperative value. One score, the Tegner-Lysholm score showed improvement, which, however, did not prove to be significant. The significantly improved results on three scores after 5 years suggest that MACT represents a suitable but cost-intensive alternative in the treatment of local cartilage defects in the knee.
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matrix associated autologous chondrocyte transplantation implantation mact MACI 5 year follow up
Knee, 2006Co-Authors: P Behrens, Thomas Bitter, Bodo Kurz, Marti RussliesAbstract:Matrix-associated autologous chondrocyte transplantation/implantation (MACT/MACI) is a new operation procedure using a cell seeded collagen matrix for the treatement of localized full-thickness cartilage defects. A prospective clinical investigation was carried out in order to clarify whether this proves suitable and confirms objective and subjective clinical improvement over a period of up to 5 years after operation. Thirty-eight patients with localised cartilage defects were treated with MACT. Within the context of clinical follow-up, these patients were evaluated for up to 5 years after the intervention. Four different scores (Meyers score, Tegner-Lysholm activity score, Lysholm-Gillquist score, ICRS score) as well as the results of six arthroscopies and biopsies obtained from four patients formed the basis of this study. For 15 patients, 5 or more years had elapsed since the operation at the time this study was completed. It was possible to obtain results 5 years postoperatively from 11 (73.3%) of these 15 patients. Overall, we included 25 patients into the evaluation with a 2-year or longer postoperative period. Five years after transplantation 8 out of 11 patients rated the function of their knee as much better or better than before. Three of the four scores showed significant improvement compared to the preoperative value. One score, the Tegner-Lysholm score showed improvement, which, however, did not prove to be significant. The significantly improved results on three scores after 5 years suggest that MACT represents a suitable but cost-intensive alternative in the treatment of local cartilage defects in the knee. D 2006 Elsevier B.V. All rights reserved.
