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Characterization of protein unfolding by fast cross-linking mass spectrometry using di-ortho-phthalaldehyde cross-linkers. Nat Commun 2022; 13:1468. [PMID: 35304446 PMCID: PMC8933431 DOI: 10.1038/s41467-022-28879-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 02/10/2022] [Indexed: 01/16/2023] Open
Abstract
Chemical cross-linking of proteins coupled with mass spectrometry is widely used in protein structural analysis. In this study we develop a class of non-hydrolyzable amine-selective di-ortho-phthalaldehyde (DOPA) cross-linkers, one of which is called DOPA2. Cross-linking of proteins with DOPA2 is 60-120 times faster than that with the N-hydroxysuccinimide ester cross-linker DSS. Compared with DSS cross-links, DOPA2 cross-links show better agreement with the crystal structures of tested proteins. More importantly, DOPA2 has unique advantages when working at low pH, low temperature, or in the presence of denaturants. Using staphylococcal nuclease, bovine serum albumin, and bovine pancreatic ribonuclease A, we demonstrate that DOPA2 cross-linking provides abundant spatial information about the conformations of progressively denatured forms of these proteins. Furthermore, DOPA2 cross-linking allows time-course analysis of protein conformational changes during denaturant-induced unfolding.
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Mirzaeei S, Taghe S, Asare-Addo K, Nokhodchi A. Polyvinyl Alcohol/Chitosan Single-Layered and Polyvinyl Alcohol/Chitosan/Eudragit RL100 Multi-layered Electrospun Nanofibers as an Ocular Matrix for the Controlled Release of Ofloxacin: an In Vitro and In Vivo Evaluation. AAPS PharmSciTech 2021; 22:170. [PMID: 34085150 PMCID: PMC8175245 DOI: 10.1208/s12249-021-02051-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 05/11/2021] [Indexed: 11/30/2022] Open
Abstract
A novel nanofiber insert was prepared with a modified electrospinning method to enhance the ocular residence time of ofloxacin (OFX) and to provide a sustained release pattern by covering hydrophilic polymers, chitosan/polyvinyl alcohol (CS/PVA) nanofibers, with a hydrophobic polymer, Eudragit RL100 in layers, and by glutaraldehyde (GA) cross-linking of CS-PVA nanofibers for the treatment of infectious conjunctivitis. The morphology of the prepared nanofibers was studied using scanning electron microscopy (SEM). The average fiber diameter was found to be 123 ± 23 nm for the single electrospun nanofiber with no cross-linking (OFX-O). The single nanofibers, cross-linked for 10 h with GA (OFX-OG), had an average fiber diameter of 159 ± 30 nm. The amount of OFX released from the nanofibers was measured in vitro and in vivo using UV spectroscopy and microbial assay methods against Staphylococcus aureus, respectively. The antimicrobial efficiency of OFX formulated in cross-linked and non-cross-linked nanofibers was affirmed by observing the inhibition zones of Staphylococcus aureus and Escherichia coli. In vivo studies using the OFX nanofibrous inserts on a rabbit eye confirmed a sustained release pattern for up to 96 h. It was found that the cross-linking of the nanofibers by GA vapor could reduce the burst release of OFX from OFX-loaded CS/PVA in one layer and multi-layered nanofibers. In vivo results showed that the AUC0–96 for the nanofibers was 9–20-folds higher compared to the OFX solution. This study thus demonstrates the potential of the nanofiber technology is being utilized to sustained drug release in ocular drug delivery systems.
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Mishra N, Kumar K, Pandey H, Raj Anand S, Yadav R, Prakash Srivastava S, Pandey R. Synthesis, characterization, optical and anti-bacterial properties of benzothiazole Schiff bases and their lanthanide (III) complexes. JOURNAL OF SAUDI CHEMICAL SOCIETY 2020. [DOI: 10.1016/j.jscs.2020.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Synthesis of 1,2-phenylenedimethanols by base-promoted reduction of isobenzofuran-1(3H)-ones with silane. CHINESE CHEM LETT 2019. [DOI: 10.1016/j.cclet.2018.11.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Zothanpuia, Passari AK, Leo VV, Chandra P, Kumar B, Nayak C, Hashem A, Abd Allah EF, Alqarawi AA, Singh BP. Bioprospection of actinobacteria derived from freshwater sediments for their potential to produce antimicrobial compounds. Microb Cell Fact 2018; 17:68. [PMID: 29729667 PMCID: PMC5935920 DOI: 10.1186/s12934-018-0912-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 04/24/2018] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Actinobacteria from freshwater habitats have been explored less than from other habitats in the search for compounds of pharmaceutical value. This study highlighted the abundance of actinobacteria from freshwater sediments of two rivers and one lake, and the isolates were studied for their ability to produce antimicrobial bioactive compounds. RESULTS 16S rRNA gene sequencing led to the identification of 84 actinobacterial isolates separated into a common genus (Streptomyces) and eight rare genera (Nocardiopsis, Saccharopolyspora, Rhodococcus, Prauserella, Amycolatopsis, Promicromonospora, Kocuria and Micrococcus). All strains that showed significant inhibition potentials were found against Gram-positive, Gram-negative and yeast pathogens. Further, three biosynthetic genes, polyketide synthases type II (PKS II), nonribosomal peptide synthetases (NRPS) and aminodeoxyisochorismate synthase (phzE), were detected in 38, 71 and 29% of the strains, respectively. Six isolates based on their antimicrobial potentials were selected for the detection and quantification of standard antibiotics using ultra performance liquid chromatography (UPLC-ESI-MS/MS) and volatile organic compounds (VOCs) using gas chromatography mass spectrometry (GC/MS). Four antibiotics (fluconazole, trimethoprim, ketoconazole and rifampicin) and 35 VOCs were quantified and determined from the methanolic crude extract of six selected Streptomyces strains. CONCLUSION Infectious diseases still remain one of the leading causes of death globally and bacterial infections caused millions of deaths annually. Culturable actinobacteria associated with freshwater lake and river sediments has the prospects for the production of bioactive secondary metabolites.
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Affiliation(s)
- Zothanpuia
- Molecular Microbiology and Systematics Laboratory, Department of Biotechnology, Mizoram University, Aizawl, Mizoram, 796004, India
| | - Ajit Kumar Passari
- Molecular Microbiology and Systematics Laboratory, Department of Biotechnology, Mizoram University, Aizawl, Mizoram, 796004, India
| | - Vincent Vineeth Leo
- Molecular Microbiology and Systematics Laboratory, Department of Biotechnology, Mizoram University, Aizawl, Mizoram, 796004, India
| | - Preeti Chandra
- SAIF, CSIR-Central Drug Research Institute (CSIR-CDRI), Lucknow, 226012, India
| | - Brijesh Kumar
- SAIF, CSIR-Central Drug Research Institute (CSIR-CDRI), Lucknow, 226012, India
| | | | - Abeer Hashem
- Botany and Microbiology Department, College of Science, King Saud University, P.O. Box. 2460, Riyadh, 11451, Saudi Arabia
- Mycology and Plant Disease Survey Department, Plant Pathology Research Institute, ARC, Giza, 12511, Egypt
| | - Elsayed Fathi Abd Allah
- Department of Plant Production, Faculty of Food & Agricultural Sciences, P.O. Box. 2460, Riyadh, 11451, Saudi Arabia
| | - Abdulaziz A Alqarawi
- Department of Plant Production, Faculty of Food & Agricultural Sciences, P.O. Box. 2460, Riyadh, 11451, Saudi Arabia
| | - Bhim Pratap Singh
- Molecular Microbiology and Systematics Laboratory, Department of Biotechnology, Mizoram University, Aizawl, Mizoram, 796004, India.
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Cai W, Wang J, Quan X, Wang Z. Preparation of bromo-substituted polyaniline with excellent antibacterial activity. J Appl Polym Sci 2017. [DOI: 10.1002/app.45657] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Wei Cai
- Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin Key Laboratory of Membrane Science and Desalination Technology, State Key Laboratory of Chemical Engineering, Collaborative Innovation Center of Chemical Science and Engineering; Tianjin University; Tianjin 300072 China
| | - Jixiao Wang
- Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin Key Laboratory of Membrane Science and Desalination Technology, State Key Laboratory of Chemical Engineering, Collaborative Innovation Center of Chemical Science and Engineering; Tianjin University; Tianjin 300072 China
| | - Xiaodong Quan
- Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin Key Laboratory of Membrane Science and Desalination Technology, State Key Laboratory of Chemical Engineering, Collaborative Innovation Center of Chemical Science and Engineering; Tianjin University; Tianjin 300072 China
| | - Zhi Wang
- Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin Key Laboratory of Membrane Science and Desalination Technology, State Key Laboratory of Chemical Engineering, Collaborative Innovation Center of Chemical Science and Engineering; Tianjin University; Tianjin 300072 China
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Sehmi SK, Allan E, MacRobert AJ, Parkin I. The bactericidal activity of glutaraldehyde-impregnated polyurethane. Microbiologyopen 2016; 5:891-897. [PMID: 27255793 PMCID: PMC5061724 DOI: 10.1002/mbo3.378] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 03/21/2016] [Accepted: 03/30/2016] [Indexed: 11/14/2022] Open
Abstract
Although glutaraldehyde is known to be bactericidal in solution, its potential use to create novel antibacterial polymers suitable for use in healthcare environments has not been evaluated. Here, novel materials were prepared in which glutaraldehyde was either incorporated into polyurethane using a simple "swell-encapsulation-shrink" method (hereafter referred to as "glutaraldehyde-impregnated polyurethane"), or simply applied to the polymer surface (hereafter referred to as "glutaraldehyde-coated polyurethane"). The antibacterial activity of glutaraldehyde-impregnated and glutaraldehyde-coated polyurethane samples was tested against Escherichia coli and Staphylococcus aureus. Glutaraldehyde-impregnated polyurethane resulted in a 99.9% reduction in the numbers of E. coli within 2 h and a similar reduction of S. aureus within 1 h, whereas only a minimal reduction in bacterial numbers was observed when the biocide was bound to the polymer surface. After 15 days, however, the bactericidal activity of the impregnated material was substantially reduced presumably due to polymerization of glutaraldehyde. Thus, although glutaraldehyde retains antibacterial activity when impregnated into polyurethane, activity is not maintained for extended periods of time. Future work should examine the potential of chemical modification of glutaraldehyde and/or polyurethane to improve the useful lifespan of this novel antibacterial polymer.
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Affiliation(s)
- Sandeep K Sehmi
- Department of Chemistry, Materials Chemistry Research Centre, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
- UCL Division of Surgery and Interventional Science, University College London, Royal Free Campus, Rowland Hill Street, London, NW3 2PF, United Kingdom
- Division of Microbial Disease, UCL Eastman Dental Institute, University College London, 256 Gray's Inn Road, London, WC1X 8LD, United Kingdom
| | - Elaine Allan
- Division of Microbial Disease, UCL Eastman Dental Institute, University College London, 256 Gray's Inn Road, London, WC1X 8LD, United Kingdom
| | - Alexander J MacRobert
- UCL Division of Surgery and Interventional Science, University College London, Royal Free Campus, Rowland Hill Street, London, NW3 2PF, United Kingdom
| | - Ivan Parkin
- Department of Chemistry, Materials Chemistry Research Centre, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom.
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RYU MIZUYUKI, KOBAYASHI TOSHIHIRO, KAWAMUKAI EMIKO, QUAN GLENLELYN, FURUTA TARO. Cytotoxicity Assessment of Residual High-Level Disinfectants. Biocontrol Sci 2013; 18:217-20. [DOI: 10.4265/bio.18.217] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Klíma J, Polášek M, Ludvík J, Urban J. Reaction of Phthalaldehyde with Aminoethanol under Different Conditions: Products and Mechanisms of Their Formation. J Heterocycl Chem 2012. [DOI: 10.1002/jhet.1121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jiří Klíma
- J. Heyrovský Institute of Physical Chemistry; Academy of Sciences of the Czech Republic; Dolejškova 3; 18223; Prague 8; Czech Republic
| | - Miroslav Polášek
- J. Heyrovský Institute of Physical Chemistry; Academy of Sciences of the Czech Republic; Dolejškova 3; 18223; Prague 8; Czech Republic
| | - Jiří Ludvík
- J. Heyrovský Institute of Physical Chemistry; Academy of Sciences of the Czech Republic; Dolejškova 3; 18223; Prague 8; Czech Republic
| | - Jiří Urban
- J. Heyrovský Institute of Physical Chemistry; Academy of Sciences of the Czech Republic; Dolejškova 3; 18223; Prague 8; Czech Republic
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Yiu HHP, Pickard MR, Olariu CI, Williams SR, Chari DM, Rosseinsky MJ. Fe3O4-PEI-RITC magnetic nanoparticles with imaging and gene transfer capability: development of a tool for neural cell transplantation therapies. Pharm Res 2011; 29:1328-43. [PMID: 22134779 DOI: 10.1007/s11095-011-0632-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 11/16/2011] [Indexed: 11/25/2022]
Abstract
PURPOSE To develop Fe(3)O(4)-PEI-RITC magnetic nanoparticles with multimodal MRI-fluorescence imaging and transfection capability, for use in neural cell replacement therapies. METHODS The Fe(3)O(4)-PEI-RITC MNPs were synthesised through a multi-step chemical grafting procedure: (i) Silanisation of MNPs with 3-iodopropyltrimethoxysilane; (ii) PEI coupling with iodopropyl groups on the MNP surface; and (iii) RITC binding onto the PEI coating. The cell labelling and transfection capabilities of these particles were evaluated in astrocytes derived from primary cultures. RESULTS Fe(3)O(4)-PEI-RITC MNPs did not exert acute toxic effects in astrocytes (at ≤ 6 days). Cells showed rapid and extensive particle uptake with up to 100% cellular labelling observed by 24 h. MRI and microscopy studies demonstrate that the particles have potential for use in bimodal MR-fluorescence imaging. Additionally, the particles were capable of delivering plasmids encoding reporter protein (approximately 4 kb) to astrocytes, albeit with low efficiencies. CONCLUSIONS Multifunctional Fe(3)O(4)-PEI-RITC MNPs were successfully prepared using a multi-step synthetic pathway, with the PEI and RITC chemically bound onto the MNP surface. Their combined MR-fluorescence imaging capabilities with additional potential for transfection applications can provide a powerful tool, after further development, for non-invasive cell tracking and gene transfer to neural transplant populations.
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Affiliation(s)
- Humphrey H P Yiu
- Chemical Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
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Inhalation of ortho-phthalaldehyde vapor causes respiratory sensitization in mice. J Allergy (Cairo) 2011; 2011:751052. [PMID: 21785612 PMCID: PMC3137992 DOI: 10.1155/2011/751052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 04/27/2011] [Indexed: 11/24/2022] Open
Abstract
Ortho-Phthalaldehyde (OPA) has been approved for high-level sterilization of heat-sensitive
medical instruments and is increasingly being used as a replacement in the healthcare industry
for glutaraldehyde, a known sensitizer. Numerous case reports have been published indicating
workers and patients experiencing respiratory problems, anaphylaxis, skin reactivity, and
systemic antibody production. Our laboratory previously demonstrated that OPA is a dermal
sensitizer in mice. The goal of the present study was to determine if OPA is a respiratory
sensitizer following inhalation exposure. Mice were exposed to OPA vapor and airway and
lymph nodes were examined for cytokine gene expression and alterations in lymphocyte
populations. Inhalation of OPA for 3 days resulted in a concentration-dependent increase in
lymphocyte proliferation, mainly B lymphocytes, in the draining lymph nodes. A secondary
challenge of mice with OPA resulted in a dramatic increase in the population of B lymphocytes
expressing IgE. Expression of Th2 (IL-4, IL-5, and IL-13) and anti/proinflammatory (IL-10,
TNFα, and IL-1β) cytokine genes was upregulated in the lymph nodes and the nasal mucosa.
Mice exposed to the higher concentrations of OPA-produced OPA-specific IgG1 antibodies
indicating systemic sensitization. These findings provide evidence that OPA has the potential to
cause respiratory sensitization in mice.
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Orsi IA, Andrade VG, Bonato PS, Raimundo LB, Herzog DS, Borie E. Glutaraldehyde release from heat-polymerized acrylic resins after disinfection and chemical and mechanical polishing. Braz Dent J 2011; 22:490-6. [DOI: 10.1590/s0103-64402011000600009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 03/27/2011] [Indexed: 11/22/2022] Open
Abstract
This study evaluated the release of glutaraldehyde from heat-polymerized acrylic resins subjected to disinfection followed by chemical and mechanical polishing. Ninety disc-shaped specimens (15 x 4 mm), 30 per resin (Lucitone 550, QC-20 and Classico), were made and assigned to 2 groups according to the type of polishing. One side of each specimen was not polished and the other was either mechanically (n=45) or chemically (n=45) polished, and immersed in water at 50°C for 1 h to allow the release of intrinsic substances and then kept in distilled water for 7 days. The specimens were disinfected by immersion in 2% glutaraldehyde for 10 min. After this period, 3 specimens from each group were immersed in water for 15, 30, 60, 120 and 240 min. For the 15-, 30-, 60-min immersions, 4 water exchanges were done at the end of period. High performance liquid chromatography (HPLC) was used to detect and quantify the glutaraldehyde released after each period. Data were analyzed statistically by two-way ANOVA and multiple comparisons were done by Tukey’s and Scheffé’s tests (α=0.05). No glutaraldehyde release was observed from the specimens with chemical polishing at any of the immersion periods, while the mechanically polished specimens released glutaraldehyde. In the groups with water exchanges, Lucitone released more disinfectant in the 15-min period (0.040 μg/mL), Classico in the 30-min (0.021 μg/mL) and 60-min (0.018 μg/mL) periods, and QC-20 the same amount (-1.760 μg/mL) in all periods. In the groups without water exchanges, Lucitone released the highest amount of disinfectant (-1.370 μg/mL), differing significantly from QC-20 (0022 g/mL) and Classico (0019 g/mL), which were similar. The findings of this showed that chemically polished specimens from the 3 resin brands did not release glutaraldehyde after different periods of immersion, while glutaraldehyde release was observed from the mechanically polished specimens, especially from those made of Lucitone resin.
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Anderson SE, Umbright C, Sellamuthu R, Fluharty K, Kashon M, Franko J, Jackson LG, Johnson VJ, Joseph P. Irritancy and allergic responses induced by topical application of ortho-phthalaldehyde. Toxicol Sci 2010; 115:435-43. [PMID: 20176622 DOI: 10.1093/toxsci/kfq054] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Although ortho-phthalaldehyde (OPA) has been suggested as an alternative to glutaraldehyde for the sterilization and disinfection of hospital equipment, the toxicity has not been thoroughly investigated. The purpose of these studies was to evaluate the irritancy and sensitization potential of OPA. The EpiDerm Skin Irritation Test was used to evaluate in vitro irritancy potential of OPA and glutaraldehyde. Treatment with 0.4125 and 0.55% OPA induced irritation, while glutaraldehyde exposure at these concentrations did not. Consistent with the in vitro results, OPA induced irritancy, evaluated by ear swelling, when mice were treated with 0.75%. Initial evaluation of the sensitization potential was conducted using the local lymph node assay at concentrations ranging from 0.005 to 0.75%. A concentration-dependent increase in lymphocyte proliferation was observed with a calculated EC3 value of 0.051% compared to that of 0.089%, previously determined for glutaraldehyde. Immunoglobulin (Ig) E-inducing potential was evaluated by phenotypic analysis of draining lymph node (DLN) cells and measurement of total and specific serum IgE levels. The 0.1 and 0.75% exposed groups yielded significant increases in the IgE+B220+ cell population in the lymph nodes while the 0.75% treated group demonstrated significant increases in total IgE, OPA-specific IgE, and OPA-specific IgG(1). In addition, significant increases in interleukin-4 messenger RNA and protein expression in the DLNs were observed in OPA-treated groups. The results demonstrate the dermal irritancy and allergic potential of OPA and raise concern about the proposed/intended use of OPA as a safe alternative to glutaraldehyde.
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Affiliation(s)
- Stacey E Anderson
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505, USA
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Neelakantan MA, Rusalraj F, Dharmaraja J, Johnsonraja S, Jeyakumar T, Sankaranarayana Pillai M. Spectral characterization, cyclic voltammetry, morphology, biological activities and DNA cleaving studies of amino acid Schiff base metal(II) complexes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2008; 71:1599-1609. [PMID: 18656419 DOI: 10.1016/j.saa.2008.06.008] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Revised: 05/07/2008] [Accepted: 06/10/2008] [Indexed: 05/26/2023]
Abstract
Metal complexes are synthesized with Schiff bases derived from o-phthalaldehyde (opa) and amino acids viz., glycine (gly) l-alanine (ala), l-phenylalanine (pal). Metal ions coordinate in a tetradentate or hexadentate manner with these N(2)O(2) donor ligands, which are characterized by elemental analysis, molar conductance, magnetic moments, IR, electronic, (1)H NMR and EPR spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Based on EPR studies, spin-Hamiltonian and bonding parameters have been calculated. The g-values calculated for copper complexes at 300K and in frozen DMSO (77K) indicate the presence of the unpaired electron in the dx2-y2 orbital. The evaluated metal-ligand bonding parameters showed strong in-plane sigma- and pi-bonding. X-ray diffraction (XRD) and scanning electron micrography (SEM) analysis provide the crystalline nature and the morphology of the metal complexes. The cyclic voltammograms of the Cu(II)/Mn(II)/VO(II) complexes investigated in DMSO solution exhibit metal centered electroactivity in the potential range -1.5 to +1.5V. The electrochemical data obtained for Cu(II) complexes explains the change of structural arrangement of the ligand around Cu(II) ions. The biological activity of the complexes has been tested on eight bacteria and three fungi. Cu(II) and Ni(II) complexes show an increased activity in comparison to the controls. The metal complexes of opapal Schiff base were evaluated for their DNA cleaving activities with calf-thymus DNA (CT DNA) under aerobic conditions. Cu(II) and VO(II) complexes show more pronounced activity in presence of the oxidant.
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Affiliation(s)
- M A Neelakantan
- Chemistry Research Centre, National Engineering College, K.R. Nagar, Kovilpatti 628 503, Thoothukudi District, Tamil Nadu, India.
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Rapoport HS, Connolly JM, Fulmer J, Dai N, Murti BH, Gorman RC, Gorman JH, Alferiev I, Levy RJ. Mechanisms of the in vivo inhibition of calcification of bioprosthetic porcine aortic valve cusps and aortic wall with triglycidylamine/mercapto bisphosphonate. Biomaterials 2006; 28:690-9. [PMID: 17027944 PMCID: PMC1829417 DOI: 10.1016/j.biomaterials.2006.09.029] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Accepted: 09/20/2006] [Indexed: 11/26/2022]
Abstract
Heart valve replacements fabricated from glutaraldehyde (Glut)-crosslinked heterograft materials, porcine aortic valves or bovine pericardium, have been widely used in cardiac surgery to treat heart valve disease. However, these bioprosthetic heart valves often fail in long-term clinical implants due to pathologic calcification of the bioprosthetic leaflets, and for stentless porcine aortic valve bioprostheses, bioprosthetic aortic wall calcification also typically occurs. Previous use of the epoxide-based crosslinker, triglycidyl amine (TGA), on cardiac bioprosthetic valve materials demonstrated superior biocompatibility, mechanics, and calcification resistance for porcine aortic valve cusps (but not porcine aortic wall) and bovine pericardium, vs. Glut-prepared controls. However, TGA preparation did not completely prevent long-term calcification of cusps or pericardium. Herein we report further mechanistic investigations of an added therapeutic component to this system, 2-mercaptoethylidene-1,1-bisphosphonic acid (MABP), a custom synthesized thiol bisphosphonate, which has previously been shown in a preliminary report to prevent bioprosthetic heterograft biomaterial calcification when used in combination with initial TGA crosslinking for 7 days. In the present studies, we have further investigated the effectiveness of MABP in experiments that examined: (1) The use of MABP after optimal TGA crosslinking, in order to avoid any competitive interference of MABP-reactions with TGA during crosslinking; (2) Furthermore, recognizing the importance of alkaline phosphatase (ALP) in the formation of dystrophic calcific nodules, we have investigated the hypothesis that the mechanism by which MABP primarily functions is through the reduction of ALP activity. Results from cell-free model systems, cell culture studies, and rat subcutaneous implants, show that materials functionalized with MABP after TGA crosslinking have reduced ALP activity, and in vivo have no significant calcification in long-term implant studies. It is concluded that bioprosthetic heart valves prepared in this fashion are compelling alternatives for Glut-prepared bioprostheses.
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Affiliation(s)
- H Scott Rapoport
- Division of Cardiology, Children's Hospital of Philadelphia, Abramson Research Center, Suite 702, 3615 Civic Center Boulevard, Philadelphia, PA 19104-4318, USA
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Mariscal A, Carnero-Varo M, Gomez E, Fernandez-Crehuet J. A fluorescence bioassay to detect residual formaldehyde from clinical materials sterilized with low-temperature steam and formaldehyde. Biologicals 2005; 33:191-6. [PMID: 16084106 DOI: 10.1016/j.biologicals.2005.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Accepted: 06/07/2005] [Indexed: 11/29/2022] Open
Abstract
A microtiter plate toxicity test based on fluorescence was developed to determine the residual concentration of formaldehyde on medical items after LTSF sterilization. The residual formaldehyde on eight common materials, some of which are used in different clinical instruments and devices were analysed after sterilization with LTSF. Formaldehyde residues were detected on cotton, filter paper, natural rubber, PVC, and silicone-coated latex, but not on polyurethane, silicone or glass. Formaldehyde never exceeded the recommended maximum concentration on clinical devices of about 5 microg/cm2. The results were compared with those obtained by means of a chemical method, the correlation being good (R2=0.9396). The biological method proposed here is fast and can be automated, which means that it could be used as a screening method when there are doubts as to the accumulation of residues on clinical materials or instruments that are going to be sterilized with LTSF.
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Affiliation(s)
- Alberto Mariscal
- Department of Preventive Medicine and Public Health, Faculty of Medicine, University of Malaga, Avda. L. Pasteur, Campus de Teatinos, E-29071 Malaga, Spain.
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Abstract
PURPOSE OF REVIEW To review recent publications relevant to hospital disinfection (and cleaning) including the reprocessing of medical instruments. RECENT FINDINGS The key question as to whether the use of disinfectants on environmental surfaces rather than cleaning with detergents only reduces nosocomial infection rates still awaits conclusive studies. New disinfectants, mainly peroxygen compounds, show good sporicidal properties and will probably replace more problematical substances such as chlorine-releasing agents. The safe reprocessing of medical devices requires a well-coordinated approach, starting with proper cleaning. New methods and substances show promising activity for preventing the transmission of prions. Different aspects of virus inactivation have been studied, and the transmissibility, e.g. of norovirus, shows the need for sound data on how different disinfectant classes perform. Biofilms or other forms of surface-adherent organisms pose an extraordinary challenge to decontamination. Although resistance to biocides is generally not judged to be as critical as antibiotic resistance, scientific data support the need for proper use, i.e. the avoidance of widespread application, especially in low concentrations and in consumer products. SUMMARY Chemical disinfection of heat-sensitive instruments and targeted disinfection of environmental surfaces are established components of hospital infection control. To avoid danger to staff, patients and the environment, prudent use as well as established safety precautions are required. New technologies and products should be evaluated with sound methods. As emerging resistant pathogens will challenge healthcare facilities in the future even more than at present, there is a need for well-designed studies addressing the role of disinfection in hospital infection control.
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Affiliation(s)
- Markus Dettenkofer
- Institute of Environmental Medicine and Hospital Epidemiology, Freiburg University Hospital, Freiburg, Germany.
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