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Mendes TAD, Pascoal SCD, Estellita MCA, Lemos MVS, Santiago SL, Mendonça JS. Chemical analysis of n-propyl gallate used as pre-treatment for resin-dentin bond strength: In vitro study. Eur J Oral Sci 2024; 132:e12970. [PMID: 38173083 DOI: 10.1111/eos.12970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 12/18/2023] [Indexed: 01/05/2024]
Abstract
This study aimed to evaluate the effect of n-propyl gallate as pre-treatment for resin-dentin bond strength. The dentin pre-treatments evaluated included propyl gallate of concentrations 0.1% (w/v), 1.0% (w/v), and 10.0% (w/v), as well as glutaraldehyde 5.0% (v/v), and distilled water as a control treatment. Dentin specimens were prepared for Fourier Transformed Infrared Spectroscopy (FT-IR) (n = 3/pre-treatment). Pre-treatments were actively applied to dentin blocks before performing the adhesive procedure to composite resin. Microtensile bond strength to dentin (μTBS) (n = 8/pre-treatment) was determined after 24 h and 6 months of storage. Data were submitted to a two-way ANOVA, followed by Tukey's post hoc test. As for FT-IR, propyl gallate 1%-treated specimens presented higher water, carbonate, collagen, and amide absorbance rates compared to other tested groups, while specimens pre-treated with glutaraldehyde and distilled water presented similar absorbance curves. Regarding μTBS, all concentrations of propyl gallate resulted in statistically significant higher bond strength values than distilled water at 24 h. After 6 months of storage, propyl gallate 0.1% was the only group that maintained μTBS over time. Propyl gallate 0.1% might be a suitable dentinal pre-treatment due to being able to present chemical bonds with demineralized dentin and providing resin-dentin bond stability after 6 months of storage.
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Affiliation(s)
| | | | | | | | - Sérgio Lima Santiago
- Graduate Program in Dentistry, Federal University of Ceará (UFC), Fortaleza, Brazil
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2
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Niazi S, Gatzioufas Z, Doroodgar F, Findl O, Baradaran-Rafii A, Liechty J, Moshirfar M. Keratoconus: exploring fundamentals and future perspectives - a comprehensive systematic review. Ther Adv Ophthalmol 2024; 16:25158414241232258. [PMID: 38516169 PMCID: PMC10956165 DOI: 10.1177/25158414241232258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 04/07/2023] [Accepted: 01/22/2024] [Indexed: 03/23/2024] Open
Abstract
Background New developments in artificial intelligence, particularly with promising results in early detection and management of keratoconus, have favorably altered the natural history of the disease over the last few decades. Features of artificial intelligence in different machine such as anterior segment optical coherence tomography, and femtosecond laser technique have improved safety, precision, effectiveness, and predictability of treatment modalities of keratoconus (from contact lenses to keratoplasty techniques). These options ingrained in artificial intelligence are already underway and allow ophthalmologist to approach disease in the most non-invasive way. Objectives This study comprehensively describes all of the treatment modalities of keratoconus considering machine learning strategies. Design A multidimensional comprehensive systematic narrative review. Data sources and methods A comprehensive search was done in the five main electronic databases (PubMed, Scopus, Web of Science, Embase, and Cochrane), without language and time or type of study restrictions. Afterward, eligible articles were selected by screening the titles and abstracts based on main mesh keywords. For potentially eligible articles, the full text was also reviewed. Results Artificial intelligence demonstrates promise in keratoconus diagnosis and clinical management, spanning early detection (especially in subclinical cases), preoperative screening, postoperative ectasia prediction after keratorefractive surgery, and guiding surgical decisions. The majority of studies employed a solitary machine learning algorithm, whereas minor studies assessed multiple algorithms that evaluated the association of various keratoconus staging and management strategies. Last but not least, AI has proven effective in guiding the implantation of intracorneal ring segments in keratoconus corneas and predicting surgical outcomes. Conclusion The efficient and widespread clinical translation of machine learning models in keratoconus management is a crucial goal of potential future approaches to better visual performance in keratoconus patients. Trial registration The article has been registered through PROSPERO, an international database of prospectively registered systematic reviews, with the ID: CRD42022319338.
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Affiliation(s)
- Sana Niazi
- Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Zisis Gatzioufas
- Department of Ophthalmology, University Eye Hospital Basel, Basel, Switzerland
| | - Farideh Doroodgar
- Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran Province, Tehran, District 6, Pour Sina St, P94V+8MF, Tehran 1416753955, Iran
- Negah Aref Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Oliver Findl
- Department of Ophthalmology, Hanusch Hospital, Vienna Institute for Research in Ocular Surgery (VIROS), Vienna, Austria
| | - Alireza Baradaran-Rafii
- Department of Ophthalmology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Jacob Liechty
- Department of Ophthalmology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Majid Moshirfar
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
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3
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Tang K, Wang F, Dai SQ, Yang ZY, Duan LY, Luo ML, Tay FR, Niu LN, Zhou W, Chen JH. Enhanced Bonding to Caries-Affected Dentin Using an Isocyanate-Based Primer. J Dent Res 2023; 102:1444-1451. [PMID: 37950512 DOI: 10.1177/00220345231199416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023] Open
Abstract
Dental caries is the most common oral disease and the most common cause of resin restorations. In minimally invasive dentistry, the principle behind cavity preparation is to remove external caries-infected dentin (CID) and preserve internal caries-affected dentin (CAD) and sound dentin (SD). The cavity floor is mainly composed of CAD, but the poor bonding performance of CAD has become a widespread concern. This study evaluated the performance of a new collagen-reactive monomer (ITCM) used as a primer to improve the bonding performance of CAD. The experimental specimens were grouped as follows: SD, CAD, and ITCM-pretreated CAD (CAD-ITCM). Dentin slices were obtained for attenuated total reflectance-Fourier transform infrared (ATR-FTIR) analysis. The bonded samples were subjected to microtensile bond strength analysis after 24 h of water storage or aging by thermocycling, and the bonding interface quality was evaluated by nanoleakage assessment, interfacial nanoindentation testing, and in situ zymography. Cytotoxicity experiments with ITCM were performed. ATR-FTIR showed that the isocyanate groups in ITCM can covalently bind and form hydrogen bonds with the collagen in CAD to mediate chemical bonding. ITCM pretreatment significantly improved the bond strength of CAD (P < 0.05), reduced interfacial nanoleakage, improved the sealing of the bonding interface, enhanced the homogeneity of the hybrid layer, and inhibited matrix metalloproteinase activity. In addition, ITCM presented acceptable biocompatibility for dental restorative application. Taken together, this study reported the application of ITCM to induce collagen-based chemical bonding in the CAD bonding system, which fills the gap in strategies to improve the bonding performance of CAD immediately and after aging and has important clinical application prospects.
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Affiliation(s)
- K Tang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - F Wang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - S Q Dai
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Z Y Yang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - L Y Duan
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - M L Luo
- Institute of Stomatology & Oral Maxilla Facial Key Laboratory, The First Medical Center, Chinese PLA General Hospital & Department of Stomatology, The First Medical Center, Chinese PLA General Hospital, Xi'an, Beijing, China
| | - F R Tay
- The Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - L N Niu
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - W Zhou
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - J H Chen
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China
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Hevler JF, Heck AJR. Higher-Order Structural Organization of the Mitochondrial Proteome Charted by In Situ Cross-Linking Mass Spectrometry. Mol Cell Proteomics 2023; 22:100657. [PMID: 37805037 PMCID: PMC10651688 DOI: 10.1016/j.mcpro.2023.100657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 09/14/2023] [Accepted: 10/04/2023] [Indexed: 10/09/2023] Open
Abstract
Mitochondria are densely packed with proteins, of which most are involved physically or more transiently in protein-protein interactions (PPIs). Mitochondria host among others all enzymes of the Krebs cycle and the oxidative phosphorylation pathway and are foremost associated with cellular bioenergetics. However, mitochondria are also important contributors to apoptotic cell death and contain their own genome indicating that they play additionally an eminent role in processes beyond bioenergetics. Despite intense efforts in identifying and characterizing mitochondrial protein complexes by structural biology and proteomics techniques, many PPIs have remained elusive. Several of these (membrane embedded) PPIs are less stable in vitro hampering their characterization by most contemporary methods in structural biology. Particularly in these cases, cross-linking mass spectrometry (XL-MS) has proven valuable for the in-depth characterization of mitochondrial protein complexes in situ. Here, we highlight experimental strategies for the analysis of proteome-wide PPIs in mitochondria using XL-MS. We showcase the ability of in situ XL-MS as a tool to map suborganelle interactions and topologies and aid in refining structural models of protein complexes. We describe some of the most recent technological advances in XL-MS that may benefit the in situ characterization of PPIs even further, especially when combined with electron microscopy and structural modeling.
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Affiliation(s)
- Johannes F Hevler
- Division of Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Albert J R Heck
- Division of Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands.
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5
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Sap KA, Guler AT, Bury A, Dekkers D, Demmers JAA, Reits EA. Identification of Full-Length Wild-Type and Mutant Huntingtin Interacting Proteins by Crosslinking Immunoprecipitation in Mice Brain Cortex. J Huntingtons Dis 2021; 10:335-347. [PMID: 34151850 PMCID: PMC8609692 DOI: 10.3233/jhd-210476] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [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] [Indexed: 11/15/2022]
Abstract
Background: Huntington’s disease is a neurodegenerative disorder caused by a CAG expansion in the huntingtin gene, resulting in a polyglutamine expansion in the ubiquitously expressed mutant huntingtin protein. Objective: Here we set out to identify proteins interacting with the full-length wild-type and mutant huntingtin protein in the mice cortex brain region to understand affected biological processes in Huntington’s disease pathology. Methods: Full-length huntingtin with 20 and 140 polyQ repeats were formaldehyde-crosslinked and isolated via their N-terminal Flag-tag from 2-month-old mice brain cortex. Interacting proteins were identified and quantified by label-free liquid chromatography-mass spectrometry (LC-MS/MS). Results: We identified 30 interactors specific for wild-type huntingtin, 14 interactors specific for mutant huntingtin and 14 shared interactors that interacted with both wild-type and mutant huntingtin, including known interactors such as F8a1/Hap40. Syt1, Ykt6, and Snap47, involved in vesicle transport and exocytosis, were among the proteins that interacted specifically with wild-type huntingtin. Various other proteins involved in energy metabolism and mitochondria were also found to associate predominantly with wild-type huntingtin, whereas mutant huntingtin interacted with proteins involved in translation including Mapk3, Eif3h and Eef1a2. Conclusion: Here we identified both shared and specific interactors of wild-type and mutant huntingtin, which are involved in different biological processes including exocytosis, vesicle transport, translation and metabolism. These findings contribute to the understanding of the roles that wild-type and mutant huntingtin play in a variety of cellular processes both in healthy conditions and Huntington’s disease pathology.
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Affiliation(s)
- Karen A Sap
- Department of Medical Biology, Amsterdam UMC, location AMC, Amsterdam, The Netherlands
| | - Arzu Tugce Guler
- Department of Medical Biology, Amsterdam UMC, location AMC, Amsterdam, The Netherlands
| | - Aleksandra Bury
- Department of Medical Biology, Amsterdam UMC, location AMC, Amsterdam, The Netherlands
| | - Dick Dekkers
- Department of Biochemistry, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jeroen A A Demmers
- Department of Biochemistry, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Eric A Reits
- Department of Medical Biology, Amsterdam UMC, location AMC, Amsterdam, The Netherlands
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More GS, Thomas AB, Chitlange SS, Nanda RK, Gajbhiye RL. Nitrogen Mustards as Alkylating Agents: A Review on Chemistry, Mechanism of Action and Current USFDA Status of Drugs. Anticancer Agents Med Chem 2020; 19:1080-1102. [PMID: 30834842 DOI: 10.2174/1871520619666190305141458] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 12/20/2018] [Accepted: 02/16/2019] [Indexed: 12/31/2022]
Abstract
BACKGROUND & OBJECTIVE Nitrogen mustard derivatives form one of the major classes of anti-cancer agents in USFDA approved drugs list. These are polyfunctional alkylating agents which are distinguished by a unique mechanism of adduct formation with DNA involving cross-linking between guanine N-7 of one strand of DNA with the other. The generated cross-linking is irreversible and leads to cell apoptosis. Hence it is of great interest to explore this class of anticancer alkylating agents. METHODS An exhaustive list of reviews, research articles, patents, books, patient information leaflets, and orange book is presented and the contents related to nitrogen mustard anti-cancer agents have been reviewed. Attempts are made to present synthesis schemes in a simplified manner. The mechanism of action of the drugs and their side effects are also systematically elaborated. RESULTS This review provides a platform for understanding all aspects of such drugs right from synthesis to their mechanism of action and side effects, and lists USFDA approved ANDA players among alkylating anticancer agents in the current market. CONCLUSION Perusing this article, generic scientists will be able to access literature information in this domain easily to gain insight into the nitrogen mustard alkylating agents for further ANDA development. It will help the scientific and research community to continue their pursuit for the design of newer and novel heterocyclic alkylating agents of this class in the coming future.
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Affiliation(s)
- Ghansham S More
- Department of Pharmaceutical Chemistry, Dr. D.Y. Patil Institute of Pharmaceutical Sciences and Research, Savitribai Phule Pune University, Pune, India
| | - Asha B Thomas
- Department of Pharmaceutical Chemistry, Dr. D.Y. Patil Institute of Pharmaceutical Sciences and Research, Savitribai Phule Pune University, Pune, India
| | - Sohan S Chitlange
- Department of Pharmaceutical Chemistry, Dr. D.Y. Patil Institute of Pharmaceutical Sciences and Research, Savitribai Phule Pune University, Pune, India
| | - Rabindra K Nanda
- Department of Pharmaceutical Chemistry, Dr. D.Y. Patil Institute of Pharmaceutical Sciences and Research, Savitribai Phule Pune University, Pune, India
| | - Rahul L Gajbhiye
- Organic & Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700 032, India
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7
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Lin X, Naidu RK, Dai J, Zhou X, Qu X, Zhou H. Scleral Cross-Linking Using Glyceraldehyde for the Prevention of Axial Elongation in the Rabbit: Blocked Axial Elongation and Altered Scleral Microstructure. Curr Eye Res 2018; 44:162-171. [PMID: 30222005 DOI: 10.1080/02713683.2018.1522647] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [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: 01/08/2023]
Abstract
BACKGROUND This study aims to assess the efficacy of the scleral collagen cross-linking method using glyceraldehyde solution for prevention of lens-induced axial elongation in New Zealand rabbits and investigate the biochemical and microstructural changes that occur. METHODS The right eyes of New Zealand rabbits aged seven weeks were randomly divided into three groups: the cross-linking group (n = 6), non-crosslinking group (n = 5), and untreated control group (n = 5). Eyes in cross-linking and non-crosslinking groups were treated with a -8.00 Diopter spherical lens over the course of two weeks. The cross-linking effects were achieved by a sub-Tenon's injection of 0.15 ml 0.5 M glyceraldehyde to eyes in the CL group. Ocular parameters were measured on the 1st, 7th, and 14th days. Biomechanical testing, light and electronic microscopy were used. RESULTS Following the cross-linking treatment, eyes in the cross-linking group had a shorter axial length compared to those in the non-crosslinking group (p = 0.006). Collagen fibrils larger than 240 nm were observed in the scleral stroma of cross-linking group, which were absent in the scleral stroma of the non-crosslinking and untreated control group. The mean ultimate stress and Young's modulus was significantly greater in the cross-linking group compared to those in the non-crosslinking and untreated control group (p < 0.05). No histological damage observed in the retina or choroid. CONCLUSIONS This study demonstrates that lens-induced axial elongation in rabbits can be effectively blocked by cross-linking using glyceraldehyde, with anatomical and mechanical modification and no deleterious effects.
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Affiliation(s)
- Xiao Lin
- a Department of Ophthalmology & Visual Science , Fudan University Eye Ear Nose and Throat Hospital, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Myopia, Ministry of Health , Fudan University , Shanghai , China.,c Shanghai Key Laboratory of Visual Impairment and Restoration , Fudan University , Shanghai , China
| | - Rajeev K Naidu
- d Concord Repatriation General Hospital , The University of Sydney , Camperdown , Australia
| | - Jinhui Dai
- a Department of Ophthalmology & Visual Science , Fudan University Eye Ear Nose and Throat Hospital, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Myopia, Ministry of Health , Fudan University , Shanghai , China.,c Shanghai Key Laboratory of Visual Impairment and Restoration , Fudan University , Shanghai , China
| | - Xingtao Zhou
- a Department of Ophthalmology & Visual Science , Fudan University Eye Ear Nose and Throat Hospital, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Myopia, Ministry of Health , Fudan University , Shanghai , China.,c Shanghai Key Laboratory of Visual Impairment and Restoration , Fudan University , Shanghai , China
| | - Xiaomei Qu
- a Department of Ophthalmology & Visual Science , Fudan University Eye Ear Nose and Throat Hospital, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Myopia, Ministry of Health , Fudan University , Shanghai , China.,c Shanghai Key Laboratory of Visual Impairment and Restoration , Fudan University , Shanghai , China
| | - Hao Zhou
- a Department of Ophthalmology & Visual Science , Fudan University Eye Ear Nose and Throat Hospital, Shanghai Medical College, Fudan University , Shanghai , China.,b Key Laboratory of Myopia, Ministry of Health , Fudan University , Shanghai , China.,c Shanghai Key Laboratory of Visual Impairment and Restoration , Fudan University , Shanghai , China
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8
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Liu Y, Dusevich V, Wang Y. Addition of Grape Seed Extract Renders Phosphoric Acid a Collagen-stabilizing Etchant. J Dent Res 2014; 93:821-7. [PMID: 24935065 DOI: 10.1177/0022034514538972] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 05/17/2014] [Indexed: 11/17/2022] Open
Abstract
Previous studies found that grape seed extract (GSE), which is rich in proanthocyanidins, could protect demineralized dentin collagen from collagenolytic activities following clinically relevant treatment. Because of proanthocyanidin's adverse interference to resin polymerization, it was believed that GSE should be applied and then rinsed off in a separate step, which in effect increases the complexity of the bonding procedure. The present study aimed to investigate the feasibility of combining GSE treatment with phosphoric acid etching to address the issue. It is also the first attempt to formulate collagen-cross-linking dental etchants. Based on Fourier-transformed infrared spectroscopy and digestion assay, it was established that in the presence of 20% to 5% phosphoric acid, 30 sec of GSE treatment rendered demineralized dentin collagen inert to bacterial collagenase digestion. Based on this positive result, the simultaneous dentin etching and collagen protecting of GSE-containing phosphoric acid was evaluated on the premise of a 30-second etching time. According to micro-Raman spectroscopy, the formulation containing 20% phosphoric acid was found to lead to overetching. Based on scanning and transmission electronic microscopy, this same formulation exhibited unsynchronized phosphoric acid and GSE penetration. Therefore, addition of GSE did render phosphoric acid a collagen-stabilizing etchant, but the preferable phosphoric acid concentration should be <20%.
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Affiliation(s)
- Y Liu
- University of Missouri-Kansas City School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, USA
| | - V Dusevich
- University of Missouri-Kansas City School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, USA
| | - Y Wang
- University of Missouri-Kansas City School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, USA
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Chapyshev SV, Ushakov EN, Chernyak AV. 15N NMR spectra and reactivity of 2,4,6-triazidopyridines, 2,4,6-triazidopyrimidine and 2,4,6-triazido-s-triazine. Magn Reson Chem 2013; 51:562-568. [PMID: 23877844 DOI: 10.1002/mrc.3987] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 06/11/2013] [Accepted: 06/25/2013] [Indexed: 06/02/2023]
Abstract
2,4,6-Triazido-s-triazine, 2,4,6-triazidopyrimidine and six different 2,4,6-triazidopyridines were studied by (15)N NMR spectroscopy. The assignment of signals in the spectra was performed using the gauge-independent atomic orbital (GIAO)-Tao-Perdew-Staroverov-Scuseria exchange-correlation functional (TPSS)h/6-311+G(d,p) calculations on the M06-2X/6-311+G(d,p) optimized molecular geometries. The Truhlar and coworkers' continuum solvation model called SMD was applied to treat solvent effects. With this approach, the root mean square error in estimations of the (15)N chemical shifts for the azido groups was just 1.9 ppm. It was shown that the different reactivity of the α- and γ-azido groups in pyridines correlates well with the chemical shifts of the Nα signals of these groups. Of two nonequivalent azido groups of azines, the azido group with the most shielded Nα signal is the most electron-deficient and reactive toward electron-rich reagents. By contrast, the azido group of azines with the most deshielded Nα signal is the most reactive toward electron-poor reagents.
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Affiliation(s)
- Sergei V Chapyshev
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, 142432, Chernogolovka, Moscow Region, Russian Federation.
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10
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Abstract
While proanthocyanidins (PA) are effective in improving collagen's resistance to collagenolytic degradation, the direct incorporation of PA into an adhesive system is detrimental to the light-curing thereof. Conversely, the use of PA as a primer could circumvent this issue, but little is known about the efficacy of PA in stabilizing collagen when applied in a clinically relevant manner. This study investigated the pre- and post-digestion morphology of an acid-etched dentin collagen layer that underwent PA treatment for time periods on a scale of seconds. The null hypothesis, that there is no difference between the PA-treated and untreated control group, had to be rejected, since it was revealed that the untreated control could not survive 1 hr of exogenous collagenase digestion, while the PA-treated collagen could sustain at least 16 hrs of digestion with no perceptible changes in collagen structure. In addition, the stabilizing effect of the gold-standard cross-linker glutaraldehyde at comparable experimental conditions was found to be almost non-existent within the 5, 15, or 30 sec of cross-linking permitted. Therefore, PA have been proven to be extraordinarily efficient in stabilizing demineralized dentin collagen against enzymatic challenges in a clinically relevant setting, likely due to the non-covalent nature of their interaction with collagen molecules.
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Affiliation(s)
- Y Liu
- University of Missouri-Kansas City School of Dentistry, 650 E 25th Street, Kansas City, MO 64108, USA
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Cremniter J, Mainardi JL, Josseaume N, Quincampoix JC, Dubost L, Hugonnet JE, Marie A, Gutmann L, Rice LB, Arthur M. Novel mechanism of resistance to glycopeptide antibiotics in Enterococcus faecium. J Biol Chem 2006; 281:32254-62. [PMID: 16943188 PMCID: PMC2084264 DOI: 10.1074/jbc.m606920200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycopeptides and beta-lactams are the major antibiotics available for the treatment of infections due to Gram-positive bacteria. Emergence of cross-resistance to these drugs by a single mechanism has been considered as unlikely because they inhibit peptidoglycan polymerization by different mechanisms. The glycopeptides bind to the peptidyl-D-Ala(4)-D-Ala(5) extremity of peptidoglycan precursors and block by steric hindrance the essential glycosyltransferase and D,D-transpeptidase activities of the penicillin-binding proteins (PBPs). The beta-lactams are structural analogues of D-Ala(4)-D-Ala(5) and act as suicide substrates of the D,D-transpeptidase module of the PBPs. Here we have shown that bypass of the PBPs by the recently described beta-lactam-insensitive L,D-transpeptidase from Enterococcus faecium (Ldt(fm)) can lead to high level resistance to glycopeptides and beta-lactams. Cross-resistance was selected by glycopeptides alone or serially by beta-lactams and glycopeptides. In the corresponding mutants, UDP-MurNAc-pentapeptide was extensively converted to UDP-MurNAc-tetrapeptide following hydrolysis of D-Ala(5), thereby providing the substrate of Ldt(fm). Complete elimination of D-Ala(5), a residue essential for glycopeptide binding, was possible because Ldt(fm) uses the energy of the L-Lys(3)-D-Ala(4) peptide bond for cross-link formation in contrast to PBPs, which use the energy of the D-Ala(4)-D-Ala(5) bond. This novel mechanism of glycopeptide resistance was unrelated to the previously identified replacement of D-Ala(5) by D-Ser or D-lactate.
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Affiliation(s)
- Julie Cremniter
- Laboratoire de Recherche Moléculaire sur les Antibiotiques
INSERM : U655IFR58Université Pierre et Marie Curie - Paris VIUniversité Paris Descartes - Paris V15, rue de l'Ecole de Médecine
75270 Paris Cedex 06,FR
| | - Jean-Luc Mainardi
- Laboratoire de Recherche Moléculaire sur les Antibiotiques
INSERM : U655IFR58Université Pierre et Marie Curie - Paris VIUniversité Paris Descartes - Paris V15, rue de l'Ecole de Médecine
75270 Paris Cedex 06,FR
- Hôpital européen Georges Pompidou
AP-HPFR
| | - Nathalie Josseaume
- Laboratoire de Recherche Moléculaire sur les Antibiotiques
INSERM : U655IFR58Université Pierre et Marie Curie - Paris VIUniversité Paris Descartes - Paris V15, rue de l'Ecole de Médecine
75270 Paris Cedex 06,FR
| | - Jean-Charles Quincampoix
- Laboratoire de Recherche Moléculaire sur les Antibiotiques
INSERM : U655IFR58Université Pierre et Marie Curie - Paris VIUniversité Paris Descartes - Paris V15, rue de l'Ecole de Médecine
75270 Paris Cedex 06,FR
- Hôpital européen Georges Pompidou
AP-HPFR
| | - Lionel Dubost
- Laboratoire de Chimie et Biochimie des Substances Naturelles
CNRS : UMR5154Muséum National d'Histoire Naturelle : USM502Département RDDM, rue Cuvier, 75005 Paris,FR
| | - Jean-Emmanuel Hugonnet
- Laboratoire de Recherche Moléculaire sur les Antibiotiques
INSERM : U655IFR58Université Pierre et Marie Curie - Paris VIUniversité Paris Descartes - Paris V15, rue de l'Ecole de Médecine
75270 Paris Cedex 06,FR
| | - Arul Marie
- Laboratoire de Chimie et Biochimie des Substances Naturelles
CNRS : UMR5154Muséum National d'Histoire Naturelle : USM502Département RDDM, rue Cuvier, 75005 Paris,FR
| | - Laurent Gutmann
- Laboratoire de Recherche Moléculaire sur les Antibiotiques
INSERM : U655IFR58Université Pierre et Marie Curie - Paris VIUniversité Paris Descartes - Paris V15, rue de l'Ecole de Médecine
75270 Paris Cedex 06,FR
- Hôpital européen Georges Pompidou
AP-HPFR
| | - Louis B. Rice
- Medical and Research Services
Louis Stokes Cleveland Veterans Affairs Medical CenterCleveland, Ohio 44106,US
| | - Michel Arthur
- Laboratoire de Recherche Moléculaire sur les Antibiotiques
INSERM : U655IFR58Université Pierre et Marie Curie - Paris VIUniversité Paris Descartes - Paris V15, rue de l'Ecole de Médecine
75270 Paris Cedex 06,FR
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Green NS, Reisler E, Houk KN. Quantitative evaluation of the lengths of homobifunctional protein cross-linking reagents used as molecular rulers. Protein Sci 2001; 10:1293-304. [PMID: 11420431 PMCID: PMC2374107 DOI: 10.1110/ps.51201] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2000] [Revised: 03/26/2001] [Accepted: 03/26/2001] [Indexed: 01/16/2023]
Abstract
UNLABELLED Homobifunctional chemical cross-linking reagents are important tools for functional and structural characterization of proteins. Accurate measures of the lengths of these molecules currently are not available, despite their widespread use. Stochastic dynamics calculations now provide quantitative measures of the lengths, and length dispersions, of 32 widely used molecular rulers. Significant differences from published data have been found. SUPPLEMENTAL MATERIAL See www.proteinscience.org
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Affiliation(s)
- N S Green
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
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