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Kontogianni GI, Bonatti AF, De Maria C, Naseem R, Coelho C, Alpantaki K, Batsali A, Pontikoglou C, Quadros P, Dalgarno K, Vozzi G, Vitale-Brovarone C, Chatzinikolaidou M. Cell Instructive Behavior of Composite Scaffolds in a Co-Culture of Human Mesenchymal Stem Cells and Peripheral Blood Mononuclear Cells. J Funct Biomater 2024; 15:116. [PMID: 38786628 DOI: 10.3390/jfb15050116] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/17/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024] Open
Abstract
The in vitro evaluation of 3D scaffolds for bone tissue engineering in mono-cultures is a common practice; however, it does not represent the native complex nature of bone tissue. Co-cultures of osteoblasts and osteoclasts, without the addition of stimulating agents for monitoring cellular cross-talk, remains a challenge. In this study, a growth factor-free co-culture of human bone marrow-derived mesenchymal stem cells (hBM-MSCs) and human peripheral blood mononuclear cells (hPBMCs) has been established and used for the evaluation of 3D-printed scaffolds for bone tissue engineering. The scaffolds were produced from PLLA/PCL/PHBV polymeric blends, with two composite materials produced through the addition of 2.5% w/v nanohydroxyapatite (nHA) or strontium-substituted nanohydroxyapatite (Sr-nHA). Cell morphology data showed that hPBMCs remained undifferentiated in co-culture, while no obvious differences were observed in the mono- and co-cultures of hBM-MSCs. A significantly increased alkaline phosphatase (ALP) activity and osteogenic gene expression was observed in co-culture on Sr-nHA-containing scaffolds. Tartrate-resistant acid phosphatase (TRAP) activity and osteoclastogenic gene expression displayed significantly suppressed levels in co-culture on Sr-nHA-containing scaffolds. Interestingly, mono-cultures of hPBMCs on Sr-nHA-containing scaffolds indicated a delay in osteoclasts formation, as evidenced from TRAP activity and gene expression, demonstrating that strontium acts as an osteoclastogenesis inhibitor. This co-culture study presents an effective 3D model to evaluate the regenerative capacity of scaffolds for bone tissue engineering, thus minimizing time-consuming and costly in vivo experiments.
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Affiliation(s)
| | - Amedeo Franco Bonatti
- Research Center E. Piaggio, Department of Information Engineering, University of Pisa, 56126 Pisa, Italy
| | - Carmelo De Maria
- Research Center E. Piaggio, Department of Information Engineering, University of Pisa, 56126 Pisa, Italy
| | - Raasti Naseem
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | | | - Kalliopi Alpantaki
- Department of Orthopaedics and Trauma, Venizeleion General Hospital of Heraklion, 70013 Heraklion, Greece
| | - Aristea Batsali
- Hemopoiesis Research Laboratory, School of Medicine, University of Crete, 70013 Heraklion, Greece
| | - Charalampos Pontikoglou
- Hemopoiesis Research Laboratory, School of Medicine, University of Crete, 70013 Heraklion, Greece
| | | | - Kenneth Dalgarno
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Giovanni Vozzi
- Research Center E. Piaggio, Department of Information Engineering, University of Pisa, 56126 Pisa, Italy
| | | | - Maria Chatzinikolaidou
- Department of Materials Science and Engineering, University of Crete, 70013 Heraklion, Greece
- Foundation for Research and Technology Hellas (FO.R.T.H)-IESL, 70013 Heraklion, Greece
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Kontogianni GI, Loukelis K, Bonatti AF, Batoni E, De Maria C, Naseem R, Dalgarno K, Vozzi G, MacManus DB, Mondal S, Dunne N, Vitale-Brovarone C, Chatzinikolaidou M. Effect of Uniaxial Compression Frequency on Osteogenic Cell Responses in Dynamic 3D Cultures. Bioengineering (Basel) 2023; 10:bioengineering10050532. [PMID: 37237602 DOI: 10.3390/bioengineering10050532] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/24/2023] [Accepted: 04/24/2023] [Indexed: 05/28/2023] Open
Abstract
The application of mechanical stimulation on bone tissue engineering constructs aims to mimic the native dynamic nature of bone. Although many attempts have been made to evaluate the effect of applied mechanical stimuli on osteogenic differentiation, the conditions that govern this process have not yet been fully explored. In this study, pre-osteoblastic cells were seeded on PLLA/PCL/PHBV (90/5/5 wt.%) polymeric blend scaffolds. The constructs were subjected every day to cyclic uniaxial compression for 40 min at a displacement of 400 μm, using three frequency values, 0.5, 1, and 1.5 Hz, for up to 21 days, and their osteogenic response was compared to that of static cultures. Finite element simulation was performed to validate the scaffold design and the loading direction, and to assure that cells inside the scaffolds would be subjected to significant levels of strain during stimulation. None of the applied loading conditions negatively affected the cell viability. The alkaline phosphatase activity data indicated significantly higher values at all dynamic conditions compared to the static ones at day 7, with the highest response being observed at 0.5 Hz. Collagen and calcium production were significantly increased compared to static controls. These results indicate that all of the examined frequencies substantially promoted the osteogenic capacity.
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Affiliation(s)
| | - Konstantinos Loukelis
- Department of Materials Science and Technology, University of Crete, 70013 Heraklion, Greece
| | - Amedeo Franco Bonatti
- Research Center E. Piaggio and Department of Information Engineering, University of Pisa, 56126 Pisa, Italy
| | - Elisa Batoni
- Research Center E. Piaggio and Department of Information Engineering, University of Pisa, 56126 Pisa, Italy
| | - Carmelo De Maria
- Research Center E. Piaggio and Department of Information Engineering, University of Pisa, 56126 Pisa, Italy
| | - Raasti Naseem
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Kenneth Dalgarno
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Giovanni Vozzi
- Research Center E. Piaggio and Department of Information Engineering, University of Pisa, 56126 Pisa, Italy
| | - David B MacManus
- School of Mechanical & Manufacturing Engineering, Dublin City University, D09 W6F4 Dublin, Ireland
| | - Subrata Mondal
- School of Mechanical & Manufacturing Engineering, Dublin City University, D09 W6F4 Dublin, Ireland
| | - Nicholas Dunne
- School of Mechanical & Manufacturing Engineering, Dublin City University, D09 W6F4 Dublin, Ireland
| | | | - Maria Chatzinikolaidou
- Department of Materials Science and Technology, University of Crete, 70013 Heraklion, Greece
- Foundation for Research and Technology Hellas (FORTH)-IESL, 70013 Heraklion, Greece
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Batoni E, Bonatti AF, De Maria C, Dalgarno K, Naseem R, Dianzani U, Gigliotti CL, Boggio E, Vozzi G. A Computational Model for the Release of Bioactive Molecules by the Hydrolytic Degradation of a Functionalized Polyester-Based Scaffold. Pharmaceutics 2023; 15:pharmaceutics15030815. [PMID: 36986675 PMCID: PMC10057942 DOI: 10.3390/pharmaceutics15030815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/19/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
This work presents a computational model to study the degradation behavior of polyester-based three-dimensional (3D) functionalized scaffolds for bone regeneration. As a case study, we investigated the behavior of a 3D-printed scaffold presenting a functionalized surface with ICOS-Fc, a bioactive protein able to stimulate bone regeneration and healing, inhibiting osteoclast activity. The aim of the model was to optimize the scaffold design to control its degradation and thus the release of grafted protein over time and space. Two different scenarios were considered: (i) a scaffold without macroporosity presenting a functionalized external surface; and (ii) a scaffold presenting an internal functionalized macroporous architecture with open channels to locally deliver the degradation products.
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Affiliation(s)
- Elisa Batoni
- Research Center E. Piaggio, Department of Information Engineering, University of Pisa, 56122 Pisa, Italy
| | - Amedeo Franco Bonatti
- Research Center E. Piaggio, Department of Information Engineering, University of Pisa, 56122 Pisa, Italy
| | - Carmelo De Maria
- Research Center E. Piaggio, Department of Information Engineering, University of Pisa, 56122 Pisa, Italy
| | - Kenneth Dalgarno
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Raasti Naseem
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Umberto Dianzani
- Department of Health Sciences, Università de Piemonte Orientale, 28100 Novara, Italy
| | - Casimiro Luca Gigliotti
- Department of Health Sciences, Università de Piemonte Orientale, 28100 Novara, Italy
- NOVAICOS s.r.l.s, Via Amico Canobio 4/6, 28100 Novara, Italy
| | - Elena Boggio
- Department of Health Sciences, Università de Piemonte Orientale, 28100 Novara, Italy
- NOVAICOS s.r.l.s, Via Amico Canobio 4/6, 28100 Novara, Italy
| | - Giovanni Vozzi
- Research Center E. Piaggio, Department of Information Engineering, University of Pisa, 56122 Pisa, Italy
- Correspondence: ; Tel.: +39-050-2217073
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Naseem R, Montalbano G, German MJ, Ferreira AM, Gentile P, Dalgarno K. Influence of PCL and PHBV on PLLA Thermal and Mechanical Properties in Binary and Ternary Polymer Blends. Molecules 2022; 27:7633. [PMID: 36364463 PMCID: PMC9657691 DOI: 10.3390/molecules27217633] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [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: 09/23/2022] [Revised: 11/01/2022] [Accepted: 11/04/2022] [Indexed: 01/15/2024] Open
Abstract
PLLA, PCL and PHBV are aliphatic polyesters which have been researched and used in a wide range of medical devices, and all three have advantages and disadvantages for specific applications. Blending of these materials is an attractive way to make a material which overcomes the limitations of the individual polymers. Both PCL and PHBV have been evaluated in polymer blends with PLLA in order to provide enhanced properties for specific applications. This paper explores the use of PCL and PHBV together with PLLA in ternary blends with assessment of the thermal, mechanical and processing properties of the resultant polymer blends, with the aim of producing new biomaterials for orthopaedic applications. DSC characterisation is used to demonstrate that the materials can be effectively blended. Blending PCL and PHBV in concentrations of 5-10% with PLLA produces materials with average modulus improved by up to 25%, average strength improved by up to 50% and average elongation at break improved by 4000%, depending on the concentrations of each polymer used. PHBV impacts most on the modulus and strength of the blends, whilst PCL has a greater impact on creep behaviour and viscosity. Blending PCL and PHBV with PLLA offers an effective approach to the development of new polyester-based biomaterials with combinations of mechanical properties which cannot be provided by any of the materials individually.
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Affiliation(s)
- Raasti Naseem
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Giorgia Montalbano
- Department of Applied Science and Technology, Politecnico di Torino, 10129 Torino, Italy
| | - Matthew J. German
- School of Dental Sciences, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Ana M. Ferreira
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Piergiorgio Gentile
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Kenneth Dalgarno
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
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Naseem R, Tzivelekis C, German MJ, Gentile P, Ferreira AM, Dalgarno K. Strategies for Enhancing Polyester-Based Materials for Bone Fixation Applications. Molecules 2021; 26:molecules26040992. [PMID: 33668466 PMCID: PMC7917714 DOI: 10.3390/molecules26040992] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/09/2021] [Accepted: 02/09/2021] [Indexed: 11/16/2022] Open
Abstract
Polyester-based materials are established options, regarding the manufacturing of bone fixation devices and devices in routine clinical use. This paper reviews the approaches researchers have taken to develop these materials to improve their mechanical and biological performances. Polymer blending, copolymerisation, and the use of particulates and fibre bioceramic materials to make composite materials and surface modifications have all been studied. Polymer blending, copolymerisation, and particulate composite approaches have been adopted commercially, with the primary focus on influencing the in vivo degradation rate. There are emerging opportunities in novel polymer blends and nanoscale particulate systems, to tune bulk properties, and, in terms of surface functionalisation, to optimise the initial interaction of devices with the implanted environment, offering the potential to improve the clinical performances of fracture fixation devices.
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Affiliation(s)
- Raasti Naseem
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (P.G.); (A.M.F.); (K.D.)
- Correspondence:
| | - Charalampos Tzivelekis
- School of Dental Sciences, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (C.T.); (M.J.G.)
| | - Matthew J. German
- School of Dental Sciences, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (C.T.); (M.J.G.)
| | - Piergiorgio Gentile
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (P.G.); (A.M.F.); (K.D.)
| | - Ana M. Ferreira
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (P.G.); (A.M.F.); (K.D.)
| | - Kenny Dalgarno
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (P.G.); (A.M.F.); (K.D.)
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6
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Affiliation(s)
- Raasti Naseem
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering Loughborough University Loughborough UK
| | - Liguo Zhao
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering Loughborough University Loughborough UK
| | | | - Helen Willcock
- Department of Materials Loughborough University Loughborough UK
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Naseem R, Zhao L, Silberschmidt VV, Liu Y, Eswaran SK, Hossainy S. Quantifying the mechanical properties of polymeric tubing and scaffold using atomic force microscopy and nanoindentation. POLYM ENG SCI 2019. [DOI: 10.1002/pen.25085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Raasti Naseem
- Wolfson School of Mechanical, Electrical and Manufacturing EngineeringLoughborough University Loughborough LE11 3TU UK
| | - Liguo Zhao
- Wolfson School of Mechanical, Electrical and Manufacturing EngineeringLoughborough University Loughborough LE11 3TU UK
| | - Vadim V. Silberschmidt
- Wolfson School of Mechanical, Electrical and Manufacturing EngineeringLoughborough University Loughborough LE11 3TU UK
| | - Yang Liu
- Wolfson School of Mechanical, Electrical and Manufacturing EngineeringLoughborough University Loughborough LE11 3TU UK
| | | | - Syed Hossainy
- Abbott Vascular 3200 Lakeside Drive Santa Clara, California, 95054 USA
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8
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Naseem R, Zhao L, Liu Y, Silberschmidt VV. Experimental and computational studies of poly-L-lactic acid for cardiovascular applications: recent progress. ACTA ACUST UNITED AC 2017. [DOI: 10.1186/s40759-017-0028-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
AbstractStents are commonly used in medical procedures to alleviate the symptoms of coronary heart disease, a prevalent modern society disease. These structures are employed to maintain vessel patency and restore blood flow. Traditionally stents are made of metals such as stainless steel or cobalt chromium; however, these scaffolds have known disadvantages. An emergence of transient scaffolds is gaining popularity, with the structure engaged for a required period whilst healing of the diseased arterial wall occurs. Polymers dominate a medical device sector, with incorporation in sutures, scaffolds and screws. Thanks to their good mechanical and biological properties and their ability to degrade naturally. Polylactic acid is an extremely versatile polymer, with its properties easily tailored to applications. Its dominance in the stenting field increases continually, with the first polymer scaffold gaining FDA approval in 2016. Still some challenges with PLLA bioresorbable materials remain, especially with regard to understanding their mechanical response, assessment of its changes with degradation and comparison of their performance with that of metallic drug-eluting stent. Currently, there is still a lack of works on evaluating both the pre-degradation properties and degradation performance of these scaffolds. Additionally, there are no established material models incorporating non-linear viscoelastic behaviour of PLLA and its evolution with in-service degradation. Assessing these features through experimental analysis accompanied by analytical and numerical studies will provide powerful tools for design and optimisation of these structures endorsing their broader use in stenting. This overview assesses the recent studies investigating mechanical and computational performance of poly(l-lactic) acid and its use in stenting applications.
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Naseem R, Silberschmidt V, Liu Y, Hossainy S, Eswaran S, Abunassar C, Zhao L. 174 Comparison of the mechanical performance of polymeric and metallic scaffolds – testing and modelling. Heart 2017. [DOI: 10.1136/heartjnl-2017-311726.172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Vassel N, Cox CD, Naseem R, Morse V, Evans RT, Power RL, Brancale A, Wann KT, Campbell AK. Enzymatic activity of albumin shown by coelenterazine chemiluminescence. LUMINESCENCE 2012; 27:234-41. [PMID: 22362656 DOI: 10.1002/bio.2357] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 01/26/2012] [Accepted: 01/31/2012] [Indexed: 11/08/2022]
Abstract
Bioluminescence, the emission of light from live organisms, occurs in 18 phyla and is the major communication system in the deep sea. It has appeared independently many times during evolution but its origins remain unknown. Coelenterazine bioluminescence discovered in luminous jellyfish is the most common chemistry causing bioluminescence in the sea, occurring in seven phyla. Sequence similarities between coelenterazine luciferases and photoproteins from different phyla are poor (often < 5%). The aim of this study was to examine albumin that binds organic substances as a coelenterazine luciferase to test the hypothesis that the evolutionary origin of a bioluminescent protein was the result of the formation of a solvent cage containing just a few key amino acids. The results show for the first time that bovine and human albumin catalysed coelenterazine chemiluminescence consistent with a mono-oxygenase, whereas gelatin and haemoglobin, an oxygen carrier, had very weak activity. Insulin also catalysed coelenterazine chemiluminescence and was increased by Zn(2+). Albumin chemiluminescence was heat denaturable, exhibited saturable substrate characteristics and was inhibited by cations that bound these proteins and by drugs that bind to human albumin drug site I. Molecular modelling confirmed the coelenterazine binding site and identified four basic amino acids: lys195, arg222, his242 and arg257, potentially important in binding and catalysis similar to naturally occurring coelenterazine bioluminescent proteins. These results support the 'solvent cage' hypothesis for the evolutionary origin of enzymatic coelenterazine bioluminescent proteins. They also have important consequences in diseases such as diabetes, gut disorders and food intolerance where a mono-oxygenase could affect cell surface proteins.
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Affiliation(s)
- N Vassel
- School of Pharmacy and Pharmaceutical Science, Cardiff University, King Edward VII Avenue, CF10 3NB Cardiff, UK
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Campbell AK, Matthews SB, Vassel N, Cox CD, Naseem R, Chaichi J, Holland IB, Green J, Wann KT. Bacterial metabolic 'toxins': a new mechanism for lactose and food intolerance, and irritable bowel syndrome. Toxicology 2010; 278:268-76. [PMID: 20851732 DOI: 10.1016/j.tox.2010.09.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 08/18/2010] [Accepted: 09/05/2010] [Indexed: 10/19/2022]
Abstract
Lactose and food intolerance cause a wide range of gut and systemic symptoms, including gas, gut pain, diarrhoea or constipation, severe headaches, severe fatigue, loss of cognitive functions such as concentration, memory and reasoning, muscle and joint pain, heart palpitations, and a variety of allergies (Matthews and Campbell, 2000; Matthews et al., 2005; Waud et al., 2008). These can be explained by the production of toxic metabolites from gut bacteria, as a result of anaerobic digestion of carbohydrates and other foods, not absorbed in the small intestine. These metabolites include alcohols, diols such as butan 2,3 diol, ketones, acids, and aldehydes such as methylglyoxal (Campbell et al., 2005, 2009). These 'toxins' induce calcium signals in bacteria and affect their growth, thereby acting to modify the balance of microflora in the gut (Campbell et al., 2004, 2007a,b). These bacterial 'toxins' also affect signalling mechanisms in cells around the body, thereby explaining the wide range of symptoms in people with food intolerance. This new mechanism also explains the most common referral to gastroenterologists, irritable bowel syndrome (IBS), and the illness that afflicted Charles Darwin for 50 years (Campbell and Matthews, 2005a,b). We propose it will lead to a new understanding of the molecular mechanism of type 2 diabetes and some cancers.
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Affiliation(s)
- A K Campbell
- Welsh School of Pharmacy, Cardiff University, King Edward VII Avenue, Cardiff CF103NB, UK.
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Sturdy A, Finch D, Naseem R, Trump D, Evens G, Webb M. Development of functional assays for BRCA1 missense mutations. Breast Cancer Res 2008. [PMCID: PMC3300770 DOI: 10.1186/bcr1951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Abstract
The ability of bentonite clay to remove Pb(II) from aqueous solutions and from nitric acid, hydrochloric acid and perchloric acid solutions (1.0-1 x 10(-5)) has been studied at different optimized conditions of concentrations, amount of adsorbent, temperature, concentration of electrolyte and pH. Maximum adsorption of Pb(II), i.e. > 98% has been achieved in aqueous solutions, while 86% is achieved from 1.0 x 10(-5) M HCl using 0.5 g of bentonite. The adsorption decreases by increasing the concentration of electrolytes. Flame atomic absorption spectrometer was used for measuring lead concentration. Isotherm analysis of adsorption data obtained at 25 degrees C, 30 degrees C, 40 degrees C and 50 degrees C showed that the adsorption pattern of lead on bentonite followed the langmuir isotherm and freundlich isotherm, respectively. DeltaH(o) and deltaS(o) were calculated from the slope and intercept of ln K(D) vs. I/T plots.
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Affiliation(s)
- R Naseem
- Central Laboratory for Environmental Analysis, Pakistan Environmental Protection Agency, Islamabad.
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