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MacDonald K, Boyd D. Investigation of Multicomponent Fluoridated Borate Glasses through a Design of Mixtures Approach. Materials (Basel) 2022; 15:6247. [PMID: 36143559 PMCID: PMC9504752 DOI: 10.3390/ma15186247] [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] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 06/16/2023]
Abstract
Due to their enhanced dissolution, solubility and reaction speed, borate glasses offer potential advantages for the design and development of therapeutic ion-release systems. However, the field remains poorly understood relative to traditional phosphosilicate and silicate bioglasses. The increased structural complexity and relative lack of published data relating to borates, particularly borofluorates, also decreases the accuracy of artificial intelligence models, which are used to predict glass properties. To develop predictive models for borofluorate networks, this paper uses a design of mixtures approach for rapid screening of composition-property relationships, including the development of polynomial equations that comprehensively establish the predictive capabilities for glass transition, density, mass loss and fluoride release. A broad range of glass compositions, extending through the boron anomaly range, were investigated, with the inclusion of 45 to 95 mol% B2O3 along with 1-50 mol% MgO, CaO and Na2O as well as 1-30% KF and NaF. This design space allows for the investigation of the impact of fluorine as well as mixed alkali-alkaline earth effects. Glass formation was found to extend past 30 mol% KF or NaF without a negative impact on glass degradation in contrast to the trends observed in phosphosilicates. The data demonstrates that fluoroborate materials offer an exceptional base for the development of fluoride-releasing materials.
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Affiliation(s)
| | - Daniel Boyd
- IR Scientific Inc., Halifax, NS B3H 0A8, Canada
- Department of Applied Oral Sciences, Dalhousie University, Halifax, NS B3H 4R2, Canada
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MacDonald K, Boudreau E, Thomas GV, Badrock TC, Davies LJ, Lloyd MJ, Spradbery PS, Turner-Cahill S, Boyd D. In vitro evaluation of Sensi-IP®: A soluble and mineralizing sensitivity solution. Heliyon 2022; 8:e08672. [PMID: 35036593 PMCID: PMC8749204 DOI: 10.1016/j.heliyon.2021.e08672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 05/19/2021] [Revised: 08/03/2021] [Accepted: 12/21/2021] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVES Sensi-IP®OG (SIP-OG) and Sensi-IP®FF (SIP-FF) are soluble bioactive glasses developed to treat dentin hypersensitivity and promote remineralization. Evaluation of their therapeutic potential to reduce dentin hypersensitivity and recover enamel strength was evaluated using standardized in vitro assessments based on simulated use. METHODS To assess dentin occlusion a visual occlusion methodology was employed. Dentin discs were subjected to twice-daily simulated brushing (for 5 days) using 0.67 g of toothpaste for 10 s. Simple prototype toothpastes containing SIP-OG and SIP-FF were compared to commercially available controls: Colgate® Sensitive Pro-Relief (CPR) and Sensodyne® Repair and Protect with NovaMin® (SRP). Samples were stored in artificial saliva between treatments. All samples were assessed at baseline and subsequent to each treatment and were scored on a 5-point categorical scale for occlusion. For enamel surface effects, test articles of SIP-OG, SIP-FF, and SIP-FF with NaF were compared to a positive (with NaF) and a negative (no NaF) control paste. Enamel samples were subjected to a pH cycling regime, providing exposure to the toothpaste slurry (i.e., 2 parts deionized water to 1 part toothpaste), mineralizing solution, and demineralizing solution over 5 days of simulated use. Samples were stored overnight in mineralizing solution. Samples were evaluated for fluoride uptake and changes to surface microhardness. RESULTS Visual occlusion scores (1 fully occluded to 5 unoccluded) were 2.6, 3.8, 4.4 and 4.0 after 1 day of simulated use for SIP-OG, SIP-FF with NaF, Colgate® Sensitive Pro-Relief and Sensodyne® Repair and Protect, respectively, decreasing to 1.0, 1.8, 3.1 and 3.9 after 5 days of application. SIP-OG provided superior occlusion at the significance level of p ≤ 0.05 at 1, 2, 3, 4, and 5 days. SIP-FF with NaF provided superior occlusion at the significance level of p ≤ 0.05 at 2, 4, and 5 days. Fluoride uptake ranged from 9.0 μg/cm2 for SIP-OG to 12.4 μg/cm2 for SIP-FF with NaF. Surface microhardness after acid cycling allowed recovery of 59 % of surface microhardness after treatment with SIP-OG or SIP-FF with NaF. SIP-OG achieved significant surface microhardness recovery versus SIP-FF alone, a NaF control paste, and a fluoride free control paste at the significance level of p ≤ 0.05. SIP-FF with NaF achieved surface microhardness recovery versus SIP-FF alone, a NaF control paste, and a fluoride free control paste at the significance level of p ≤ 0.05. CONCLUSIONS Superior occlusion of dentin tubules was observed with both novel additives compared to commercially available toothpastes. A build-up effect with increasing occlusion was noted with repeated application for both novel additives and ascribed to mineralization effects, as supported by surface microhardness recovery on initial enamel lesions.
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Affiliation(s)
- Kathleen MacDonald
- IR Scientific Inc., Box 51, 1344 Summer St, Halifax, N.S, B3H 0A8, Canada
| | - Effie Boudreau
- IR Scientific Inc., Box 51, 1344 Summer St, Halifax, N.S, B3H 0A8, Canada
| | | | | | | | | | | | | | - Daniel Boyd
- Department of Applied Oral Sciences, Faculty of Dentistry, Dalhousie University, B3H 4R2, Canada
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O'Neill C, Price RB, Boyd D. Gloss Retention on Enamel and Resin Composite Surfaces After Brushing Teeth with Commercial and Modified Dentifrices. J Can Dent Assoc 2021; 87:l6. [PMID: 34343069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
OBJECTIVES We examined the surface gloss and roughness of a dental composite and human enamel after brushing with a new bioactive glass (BCF201) additive designed to treat dentine hypersensitivity. METHODS We prepared 2 cohorts of samples: a resin-based composite (RBC) and human enamel. Each cohort received 20 000 brushing cycles with Colgate Optic White Enamel (Colgate Optic), Sensodyne Whitening Repair and Protect (Sensodyne), Colgate Enamel Health Sensitivity Relief (Colgate-EN) with and without BCF201 added or Germiphene Gel 7 HT (Gel 7) with and without BCF201 added. The average gloss and roughness of the enamel and RBC surfaces were measured before brushing and after 20 000 back-and-forth brushing cycles. A linear regression function was applied to the gloss results, and the data were analyzed using ANOVA and a Tukey post-hoc test (α = 0.05). RESULTS After 20 000 brushing cycles, the control (Gel 7) had no significant effect on the gloss or roughness of the RBC. However, the choice of dentifrice had a significant effect on both gloss and roughness (p < 0.001). With respect to RBC, after brushing, surface roughness was ranked from smoothest to roughest: Gel 7 = Gel 7 plus BCF201 > Colgate-EN plus BCF201 = Colgate Optic = Colgate-EN > Sensodyne. With respect to enamel, the smoothest to the roughest surfaces after brushing were: Gel 7 plus BCF201 = Sensodyne = Colgate-EN plus BCF201 > Gel 7 = Colgate Optic = Colgate-EN. CONCLUSION The bioactive glass additive had no adverse effect on the surface roughness or gloss of human enamel or RBC. SIGNIFICANCE The addition of BCF201 appears to have a polishing effect on RBC and enamel and reduced the abrasive effects of Colgate-EN on RBC and enamel.
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Lee-Archer P, Boyd D, Du T, Elliott R, Graydon C, Paterson N, Morawska L. A comparison of anesthetic protective barriers for the management of COVID-19 pediatric patients. Paediatr Anaesth 2021; 31:323-329. [PMID: 33280199 DOI: 10.1111/pan.14103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 11/24/2020] [Accepted: 12/01/2020] [Indexed: 01/25/2023]
Abstract
BACKGROUND Barrier techniques, such as plastic sheets or intubation boxes, are purported to offer additional protection for healthcare workers. AIMS To assess the functionality, perceived safety, droplet protection, and aerosol protection of several barrier techniques. METHODS Firstly, a simulation study with 12 different laryngoscopists was conducted to assess the time taken to perform an intubation (via direct laryngoscopy, via video laryngoscopy, and via a bougie) with four different barrier techniques (personal protective equipment only, a plastic sheet, a tented plastic sheet, and an intubation box). Secondly, a cough at the time of intubation was simulated using ultraviolet dye to assess the spread of droplets; and thirdly, smoke was used to assess the spread of aerosols. RESULTS Intubation time using the box was noninferior to using no barrier. Based on subjective ratings by the laryngoscopists, the most functional technique was no barrier followed by the intubation box, then the tented sheet, and then the plastic sheet. The technique that conferred the highest feeling of safety to the laryngoscopists was the intubation box, followed by the tented sheet, then no barrier, and then the plastic sheet. All the barriers prevented the ultraviolet dye contaminating the head and torso of the laryngoscopist. Smoke remained within the intubation box if plastics sheets were used to cover the openings and suction was ineffective at clearing it. With no barrier in place, smoke was effectively cleared away from the patient in a theater with laminar flow but tended to spread up toward the laryngoscopist in a room without laminar flow. CONCLUSIONS A well-designed intubation box is an effective barrier against droplets and is noninferior to no barrier in relation to intubation time. However, a box interferes with laminar flow in theaters with formal ventilation systems and may result in accumulation of aerosols if it is completely enclosed.
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Affiliation(s)
- Paul Lee-Archer
- Department of Anaesthesia, Queensland Children's Hospital, Brisbane, Queensland, Australia
| | - Daniel Boyd
- Department of Anaesthesia, Queensland Children's Hospital, Brisbane, Queensland, Australia
| | - Trung Du
- Department of Anaesthesia, Queensland Children's Hospital, Brisbane, Queensland, Australia
| | - Robert Elliott
- Department of Anaesthesia, Queensland Children's Hospital, Brisbane, Queensland, Australia
| | - Cameron Graydon
- Department of Anaesthesia, Queensland Children's Hospital, Brisbane, Queensland, Australia
| | - Neil Paterson
- Department of Anaesthesia, Queensland Children's Hospital, Brisbane, Queensland, Australia
| | - Lidia Morawska
- Science and Engineering Faculty, School of Earth & Atmospheric Sciences, Queensland University of Technology, Brisbane, Queensland, Australia.,International Laboratory for Air Quality and Health, Brisbane, Queensland, Australia
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Lee‐Archer P, Blackall S, Campbell H, Boyd D, Patel B, McBride C. Increased incidence of complicated appendicitis during the COVID-19 pandemic. J Paediatr Child Health 2020; 56:1313-1314. [PMID: 32830891 PMCID: PMC7461078 DOI: 10.1111/jpc.15058] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 06/15/2020] [Indexed: 12/27/2022]
Affiliation(s)
- Paul Lee‐Archer
- Department of AnaesthesiaQueensland Children's HospitalBrisbaneQueenslandAustralia
| | - Sean Blackall
- Department of AnaesthesiaQueensland Children's HospitalBrisbaneQueenslandAustralia
| | - Holly Campbell
- Department of SurgeryQueensland Children's HospitalBrisbaneQueenslandAustralia
| | - Daniel Boyd
- Department of AnaesthesiaQueensland Children's HospitalBrisbaneQueenslandAustralia
| | - Bhavesh Patel
- Department of SurgeryQueensland Children's HospitalBrisbaneQueenslandAustralia
| | - Craig McBride
- Department of SurgeryQueensland Children's HospitalBrisbaneQueenslandAustralia
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Doucet J, MacDonald K, Lee C, Hana RA, Soulez G, Boyd D. The feasibility of degradable glass microspheres as transient embolic medical devices. J Biomater Appl 2020; 35:615-632. [PMID: 32722998 DOI: 10.1177/0885328220944871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The deliberate occlusion of blood flow through transarterial embolization is currently being used to treat conditions ranging from hemorrhages to hypervascular tumors. Degradable, imageable high borate glass microspheres (BRS2) were developed and tested to improve lesion targeting and promote a temporary vascular occlusion which is sufficient for most embolization procedure. A 48 hour pilot study, in a swine renal model, was conducted to assess the embolization effectiveness and potential risks of this new embolic agent. Bilateral embolization of the caudal branch of the renal arteries using test and control particles were performed in 4 pigs. Embolization efficacy, recanalization and resulting ischemia were evaluated at different time frame (0, 24 and 48 hours). The primary outcomes for this study were the assessment of: (i) embolization effectiveness, and (ii) vessel recanalization. The test article was found to occlude vessels as effectively as the control microspheres, with the use of a smaller volume of microspheres. At the 24 hour time point, over 95% of the material was found to be completely degraded, although little to no recanalization was observed. This data suggests that BRS2 is an effective embolic agent, however further investigations into the method of delivery are required prior to clinical implementation.
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Affiliation(s)
- Jensen Doucet
- Department of Medicine, Dalhousie University, Halifax, Canada
| | | | - Changseok Lee
- Department of Medicine, Dalhousie University, Halifax, Canada
| | - Renato Abu Hana
- Centre Hospitalier de L'Universite de Montreal, Montreal, Canada
| | - Gilles Soulez
- Centre Hospitalier de L'Universite de Montreal, Montreal, Canada
| | - Daniel Boyd
- Department of Medicine, Dalhousie University, Halifax, Canada
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Henry EC, Mawko G, Tonkopi E, Frampton J, Kehoe S, Boyd D, Abraham R, Gregoire M, O’Connell K, Kappadath SC, Syme A. Quantification of the inherent radiopacity of glass microspheres for precision dosimetry in yttrium-90 radioembolization. Biomed Phys Eng Express 2019. [DOI: 10.1088/2057-1976/ab36c2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Henry C, Tonkopi E, O’Connell K, Westcott M, Lewandowski R, Liu D, Boyd D, Kehoe S, Gregoire M, Mawko G, Kappadath S, Syme A, Abraham R. Abstract No. 531 Novel radiopaque Yttrium-90 glass microspheres in a porcine model: clinical potential for real-time targeting and dosimetry. J Vasc Interv Radiol 2019. [DOI: 10.1016/j.jvir.2018.12.612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Myles PS, Myles DB, Galagher W, Boyd D, Chew C, MacDonald N, Dennis A. Measuring acute postoperative pain using the visual analog scale: the minimal clinically important difference and patient acceptable symptom state. Br J Anaesth 2018; 118:424-429. [PMID: 28186223 DOI: 10.1093/bja/aew466] [Citation(s) in RCA: 427] [Impact Index Per Article: 71.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2016] [Indexed: 12/16/2022] Open
Abstract
Background The 100 mm visual analog scale (VAS) score is widely used to measure pain intensity after surgery. Despite this widespread use, it is unclear what constitutes the minimal clinically important difference (MCID); that is, what minimal change in score would indicate a meaningful change in a patient's pain status. Methods We enrolled a sequential, unselected cohort of patients recovering from surgery and used a VAS to quantify pain intensity. We compared changes in the VAS with a global rating-of-change questionnaire using an anchor-based method and three distribution-based methods (0.3 sd , standard error of the measurement, and 5% range). We then averaged the change estimates to determine the MCID for the pain VAS. The patient acceptable symptom state (PASS) was defined as the 25th centile of the VAS corresponding to a positive patient response to having made a good recovery from surgery. Results We enrolled 224 patients at the first postoperative visit, and 219 of these were available for a second interview. The VAS scores improved significantly between the first two interviews. Triangulation of distribution and anchor-based methods resulted in an MCID of 9.9 for the pain VAS, and a PASS of 33. Conclusions Analgesic interventions that provide a change of 10 for the 100 mm pain VAS signify a clinically important improvement or deterioration, and a VAS of 33 or less signifies acceptable pain control (i.e. a responder), after surgery.
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Affiliation(s)
- P S Myles
- Department of Anaesthesia and Perioperative Medicine, Alfred Hospital and Monash University, Melbourne, Victoria, Australia.,Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - D B Myles
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - W Galagher
- Department of Anaesthesia and Perioperative Medicine, Alfred Hospital and Monash University, Melbourne, Victoria, Australia
| | - D Boyd
- Department of Anaesthesia and Perioperative Medicine, Alfred Hospital and Monash University, Melbourne, Victoria, Australia
| | - C Chew
- Department of Anaesthesia and Perioperative Medicine, Alfred Hospital and Monash University, Melbourne, Victoria, Australia
| | - N MacDonald
- Department of Anaesthesia, Royal Women's Hospital, Parkville, Victoria, Australia
| | - A Dennis
- Department of Anaesthesia, Royal Women's Hospital, Parkville, Victoria, Australia
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MacDonald K, Boyd D. Mechanical loading, an important factor in the evaluation of ion release from bone augmentation materials. Sci Rep 2018; 8:14225. [PMID: 30242183 PMCID: PMC6154963 DOI: 10.1038/s41598-018-32325-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 09/05/2018] [Indexed: 11/10/2022] Open
Abstract
The controlled release of therapeutic inorganic ions from biomaterials is an emerging area of international research. One of the foci for this research is the development of materials, which spatially and temporally modulate therapeutic release, via controlled degradation in the intended physiological environment. Crucially however, our understanding of the release kinetics for such systems remains limited, particularly with respect to the influence of physiological loading. Consequently, this study was designed to investigate the effect of dynamic mechanical loading on a composite material intended to stabilize, reinforce and strengthen vertebral bodies. The composite material contains a borate glass engineered to release strontium as a therapeutic inorganic ion at clinically relevant levels over extended time periods. It was observed that both cyclic (6 MPa 2 Hz) and static (4.3 MPa) compressive loading significantly increased the release of strontium ions in comparison to the static unloaded case. The observed alterations in ion release kinetics suggest that the mechanical loading of the implantation environment should be considered when evaluating the ion release kinetics.
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Affiliation(s)
- Kathleen MacDonald
- School of Biomedical Engineering, Dalhousie University, Halifax, B3H 4R2, Canada
| | - Daniel Boyd
- School of Biomedical Engineering, Dalhousie University, Halifax, B3H 4R2, Canada.
- Applied Oral Sciences, Dalhousie University, Halifax, B3H 4R2, Canada.
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Foster Page LA, Boyd D, Fuge K, Stevenson A, Goad K, Sim D, Thomson WM. The effect of bitewing radiography on estimates of dental caries experience among children differs according to their disease experience. BMC Oral Health 2018; 18:137. [PMID: 30092796 PMCID: PMC6085693 DOI: 10.1186/s12903-018-0596-1] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 07/25/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Radiography is a regularly used and accepted adjunct to visual examination in the diagnosis of dental caries. It is assumed that not using radiographs can lead to underestimation of dental caries experience with most reports having involved studies of young adults or adolescents, and been focused on the permanent dentition. The aim of this study was to determine the relative contributions of bitewing radiography and clinical examination in the detection of dental caries in primary molars and to determine whether those contributions differ according to caries experience. METHODS A cross-sectional study was conducted, involving examinations undertaken in dental clinics. Bitewing radiographs taken at the time of the clinical examination were developed and read later, with the data from those used at the analysis stage to adjust the caries diagnosis for the mesial, occlusal and distal surfaces of the primary molar teeth. Children's clinically determined dmfs score was used to allocate them to one of three caries experience groups (0 dmfs, 1-8 dmfs, or 9+ dmfs). RESULTS Of the 501 three-to-eight-year-old children examined, nearly three-quarters were younger than six. Caries prevalence and mean dmfs after clinical examination alone and following radiographs were 63.1% and 4.6 (sd, 6.2), and 74.7% and 5.8 (sd, 6.5) respectively. Among children with a dmfs of 1-8, the number of lesions missed during the clinical examination was greater than the number of 106 (25.6%) in children with a dmfs of 9+. In the 185 children with no apparent caries at clinical examination, 124 lesions were detected radiographically, among 58 (46.8%) of those. CONCLUSIONS Taking bitewing radiographs in young children is not without challenges or risks, and it must be undertaken with these in mind. Diagnostic yields from bitewing radiographs are greater for children with greater caries experience. The findings of this study further support the need to consider using bitewing radiographs in young children to enhance the management of lesions not detected by a simple visual examination alone. TRIAL REGISTRATION ACTRN12614000844640 .
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Affiliation(s)
- L A Foster Page
- Department of Oral Sciences, Faculty of Dentistry, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.
| | - D Boyd
- Department of Oral Sciences, University of Otago, Dunedin, New Zealand
| | - K Fuge
- Community Oral Health Service, Hutt Valley Hospital, Wellington, New Zealand
| | - A Stevenson
- Hutt Valley District Health Board, Wellington, New Zealand
| | - K Goad
- Waikato District Health Board, Hamilton, New Zealand
| | - D Sim
- Southern District Health Board, Dunedin, New Zealand
| | - W M Thomson
- Department of Oral Sciences, University of Otago, Dunedin, New Zealand
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Abstract
SummaryThere is now ample evidence that the proteolytic action of urokinase (UK) is potentiated by a specific cell surface receptor. The present study was undertaken to assess the role of UK as a modulator of its receptor. GEO colonic cells, which secrete relatively low levels of UK (≃0.1 nM/72 h per 106 cells) and display approximately 104 receptors per cell, 10% of which are "tagged" with the endogenous plasminogen activator (PA), was selected for the study. A 90% reduction in the specific binding of radioactive DFP-UK was observed for cells cultivated in the presence of two-chain (TC) UK (M
r 55,000). This only partly reflected occupation of the receptors with UK supplied in the culture medium, since the specific binding of the radioligand was still reduced by 60% after an acid pretreatment, which dissociates receptor-bound UK. The reduction in radioactive DFP-UK binding to cells treated with high molecular weight UK, either in the single or two-chain form, was both concentration and time dependent. Maximum reductions (70%) were achieved by treatment of the cells for 24 h with 1 nM of the plasminogen activator. In contrast, low molecular weight UK, which lacks part of the UK A chain, had no effect on ligand binding. Attenuation of radioactive DFP-UK binding to UK treated GEO cells was a consequence of a 60% reduction in the number of binding sites. Treatment of GEO cells with an antibody, which blocks the binding of endogenous UK to its receptor, augmented radioactive DFP-UK binding by two-fold. These data indicate that for one colonic cell line, at least, UK down-regulates its own binding site subsequent to it being bound to the receptor.
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Affiliation(s)
- W Hollas
- The Department of Tumor Biology, M. D. Anderson Cancer Center, Houston, USA
| | - D Boyd
- The Department of Tumor Biology, M. D. Anderson Cancer Center, Houston, USA
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Hollas W, Hoosein N, Chung LWK, Mazar A, Henkin J, Kariko K, Barnathan ES, Boyd D. Expression of Urokinase and Its Receptor in Invasive and Non-Invasive Prostate Cancer Cell Lines. Thromb Haemost 2018. [DOI: 10.1055/s-0038-1646340] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
SummaryWe previously reported that extracellular matrix invasion by the prostate cancer cell lines, PC-3 and DU-145 was contingent on endogenous urokinase being bound to a specific cell surface receptor. The present study was undertaken to characterize the expression of both urokinase and its receptor in the non-invasive LNCaP and the invasive PC-3 and DU-145 prostate cells. Northern blotting indicated that the invasive PC-3 cells, which secreted 10 times more urokinase (680 ng/ml per 106 cells per 48 h) than DU-145 cells (63 ng/ml per 106 cells per 48 h), had the most abundant transcript for the plasminogen activator. This, at least, partly reflected a 3 fold amplification of the urokinase gene in the PC-3 cells. In contrast, urokinase-specific transcript could not be detected in the non-invasive LNCaP cells previously characterized as being negative for urokinase protein. Southern blotting indicated that this was not a consequence of deletion of the urokinase gene. Crosslinking of radiolabelled aminoterminal fragment of urokinase to the cell surface indicated the presence of a 51 kDa receptor in extracts of the invasive PC-3 and DU-145 cells but not in extracts of the non-invasive LNCaP cells. The amount of binding protein correlated well with binding capacities calculated by Scatchard analysis. In contrast, the steady state level of urokinase receptor transcript was a poor predictor of receptor display. PC-3 cells, which were equipped with 25,000 receptors per cell had 2.5 fold more steady state transcript than DU-145 cells which displayed 93,000 binding sites per cell.
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Affiliation(s)
- W Hollas
- The Department of Tumor Biology, M. D. Anderson Cancer Center, Houston, TX, USA
| | - N Hoosein
- The Urology Research Laboratory, M. D. Anderson Cancer Center, Houston, TX, USA
| | - L W K Chung
- The Urology Research Laboratory, M. D. Anderson Cancer Center, Houston, TX, USA
| | - A Mazar
- The Thrombolytics Venture Abbott Labs, Abbott Park, IL, USA
| | - J Henkin
- The Thrombolytics Venture Abbott Labs, Abbott Park, IL, USA
| | - K Kariko
- The Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - E S Barnathan
- The Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - D Boyd
- The Department of Tumor Biology, M. D. Anderson Cancer Center, Houston, TX, USA
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Church C, Mawko G, Archambault JP, Lewandowski R, Liu D, Kehoe S, Boyd D, Abraham R, Syme A. Absorbed dose kernel and self-shielding calculations for a novel radiopaque glass microsphere for transarterial radioembolization. Med Phys 2017; 45:934-942. [PMID: 29206288 DOI: 10.1002/mp.12717] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [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: 04/13/2017] [Revised: 11/22/2017] [Accepted: 11/27/2017] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Radiopaque microspheres may provide intraprocedural and postprocedural feedback during transarterial radioembolization (TARE). Furthermore, the potential to use higher resolution x-ray imaging techniques as opposed to nuclear medicine imaging suggests that significant improvements in the accuracy and precision of radiation dosimetry calculations could be realized for this type of therapy. This study investigates the absorbed dose kernel for novel radiopaque microspheres including contributions of both short and long-lived contaminant radionuclides while concurrently quantifying the self-shielding of the glass network. METHODS Monte Carlo simulations using EGSnrc were performed to determine the dose kernels for all monoenergetic electron emissions and all beta spectra for radionuclides reported in a neutron activation study of the microspheres. Simulations were benchmarked against an accepted 90 Y dose point kernel. Self-shielding was quantified for the microspheres by simulating an isotropically emitting, uniformly distributed source, in glass and in water. The ratio of the absorbed doses was scored as a function of distance from a microsphere. The absorbed dose kernel for the microspheres was calculated for (a) two bead formulations following (b) two different durations of neutron activation, at (c) various time points following activation. RESULTS Self-shielding varies with time postremoval from the reactor. At early time points, it is less pronounced due to the higher energies of the emissions. It is on the order of 0.4-2.8% at a radial distance of 5.43 mm with increased size from 10 to 50 μm in diameter during the time that the microspheres would be administered to a patient. At long time points, self-shielding is more pronounced and can reach values in excess of 20% near the end of the range of the emissions. Absorbed dose kernels for 90 Y, 90m Y, 85m Sr, 85 Sr, 87m Sr, 89 Sr, 70 Ga, 72 Ga, and 31 Si are presented and used to determine an overall kernel for the microspheres based on weighted activities. The shapes of the absorbed dose kernels are dominated at short times postactivation by the contributions of 70 Ga and 72 Ga. Following decay of the short-lived contaminants, the absorbed dose kernel is effectively that of 90 Y. After approximately 1000 h postactivation, the contributions of 85 Sr and 89 Sr become increasingly dominant, though the absorbed dose-rate around the beads drops by roughly four orders of magnitude. CONCLUSIONS The introduction of high atomic number elements for the purpose of increasing radiopacity necessarily leads to the production of radionuclides other than 90 Y in the microspheres. Most of the radionuclides in this study are short-lived and are likely not of any significant concern for this therapeutic agent. The presence of small quantities of longer lived radionuclides will change the shape of the absorbed dose kernel around a microsphere at long time points postadministration when activity levels are significantly reduced.
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Affiliation(s)
- Cody Church
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada
| | - George Mawko
- Department of Diagnostic Imaging, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Medical Physics, Nova Scotia Health Authority, Halifax, Nova Scotia, Canada
| | | | - Robert Lewandowski
- Interventional Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - David Liu
- Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Sharon Kehoe
- ABK Biomedical Inc., Halifax, Nova Scotia, Canada.,Department of Applied Oral Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Daniel Boyd
- ABK Biomedical Inc., Halifax, Nova Scotia, Canada.,Department of Applied Oral Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Robert Abraham
- Department of Diagnostic Imaging, Dalhousie University, Halifax, Nova Scotia, Canada.,ABK Biomedical Inc., Halifax, Nova Scotia, Canada
| | - Alasdair Syme
- Department of Medical Physics, Nova Scotia Health Authority, Halifax, Nova Scotia, Canada.,Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia, Canada
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15
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Lubenko A, Burslem S, Fairclough L, Pope J, Boyd D, Bacon J. A New Qualitative Variant of the RhE Antigen Revealed by Heterogeneity among Anti-E Sera. Vox Sang 2017. [DOI: 10.1159/000461294] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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16
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Murakami M, Arunasalam V, Bell J, Bell M, Bitter M, Blanchard W, Boody F, Boyd D, Bretz N, Bush C, Callen J, Cecchi J, Colchin R, Coonrod J, Davis S, Dimock D, Dylla H, Efthimion P, Emerson L, England A, Eubank H, Fonck R, Fredrickson E, Furth H, Grisham L, von Goeler S, Goldston R, Grek B, Grove D, Hawryluk R, Hendel H, Hill K, Hulse R, Johnson D, Johnson L, Kaita R, Kamperschroer J, Kaye S, Kikuchi M, Kilpatrick S, Kugel H, LaMarche P, Little R, Ma C, Manos D, Mansfield D, McCarthy M, McCann R, McCune D, McGuire K, Meade D, Medley S, Mikkelsen D, Mueller D, Nieschmidt E, Owens D, Pare V, Park H, Prichard B, Ramsey A, Rasmussen D, Roquemore A, Rutherford P, Sauthoff N, Schivell J, Schwob JL, Scott S, Sesnic S, Shimada M, Simpkins J, Sinnis J, Stauffer F, Stratton B, Suckewer S, Tait G, Taylor G, Tenney F, Thomas C, Towner H, Ulrickson M, Wieland R, Williams M, Wong KL, Wouters A, Yamada H, Yoshikawa S, Young K, Zarnstorff M. Confinement Studies In TFTR. ACTA ACUST UNITED AC 2017. [DOI: 10.13182/fst85-a40115] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- M. Murakami
- Permanent Address: Oak Ridge National Laboratory, Oak Ridge, TN
| | - V. Arunasalam
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - J.D. Bell
- Permanent Address: Oak Ridge National Laboratory, Oak Ridge, TN
| | - M.G. Bell
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - M. Bitter
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - W.R. Blanchard
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - F. Boody
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - D. Boyd
- Permanent Address: University of Maryland, College Park, MD
| | - N. Bretz
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - C.E. Bush
- Permanent Address: Oak Ridge National Laboratory, Oak Ridge, TN
| | - J.D. Callen
- Permanent Address: University of Wisconsin, Madison, WI
| | - J.L. Cecchi
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - R.J. Colchin
- Permanent Address: Oak Ridge National Laboratory, Oak Ridge, TN
| | - J. Coonrod
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - S.L. Davis
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - D. Dimock
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - H.F. Dylla
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - P.C. Efthimion
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - L.C. Emerson
- Permanent Address: Oak Ridge National Laboratory, Oak Ridge, TN
| | - A.C. England
- Permanent Address: Oak Ridge National Laboratory, Oak Ridge, TN
| | - H.P. Eubank
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - R. Fonck
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - E. Fredrickson
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - H.P. Furth
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - L.R. Grisham
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - S. von Goeler
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - R.J. Goldston
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - B. Grek
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - D.J. Grove
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - R.J. Hawryluk
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - H. Hendel
- Permanent Address: RCA David Sarnoff Research Center, Princeton, NJ
| | - K.W. Hill
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - R. Hulse
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - D. Johnson
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - L.C. Johnson
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - R. Kaita
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - J. Kamperschroer
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - S.M. Kaye
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - M. Kikuchi
- Permanent Address: Japan Atomic Energy Research Institute, Japan
| | - S. Kilpatrick
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - H. Kugel
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - P.H. LaMarche
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - R. Little
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - C.H. Ma
- Permanent Address: Oak Ridge National Laboratory, Oak Ridge, TN
| | - D. Manos
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - D. Mansfield
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - M. McCarthy
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - R.T. McCann
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - D.C. McCune
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - K. McGuire
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - D.M. Meade
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - S.S. Medley
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - D.R. Mikkelsen
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - D. Mueller
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | | | - D.K. Owens
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - V.K. Pare
- Permanent Address: Oak Ridge National Laboratory, Oak Ridge, TN
| | - H. Park
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - B. Prichard
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - A. Ramsey
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - D.A. Rasmussen
- Permanent Address: Oak Ridge National Laboratory, Oak Ridge, TN
| | - A.L. Roquemore
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - P.H. Rutherford
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - N.R. Sauthoff
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - J. Schivell
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - J-L. Schwob
- Permanent Address: Hebrew University of Jerusalem, Israel
| | - S.D Scott
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - S. Sesnic
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - M. Shimada
- Permanent Address: Japan Atomic Energy Research Institute, Japan
| | - J.E. Simpkins
- Permanent Address: Oak Ridge National Laboratory, Oak Ridge, TN
| | - J. Sinnis
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - F. Stauffer
- Permanent Address: University of Maryland, College Park, MD
| | - B. Stratton
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - S. Suckewer
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - G.D. Tait
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - G. Taylor
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - F. Tenney
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - C.E. Thomas
- Permanent Address: Oak Ridge National Laboratory, Oak Ridge, TN
| | - H.H. Towner
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - M. Ulrickson
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - R. Wieland
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - M. Williams
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - K-L. Wong
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - A. Wouters
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - H. Yamada
- Permanent Address: Univeristy of Tokyo, Japan
| | - S. Yoshikawa
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - K.M Young
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
| | - M.C. Zarnstorff
- Plasma Physics Laboratory, Princeton University P.O. Box 451, Princeton, NJ 08544
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17
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MacDonald K, Price RB, Boyd D. The Feasibility and Functional Performance of Ternary Borate-Filled Hydrophilic Bone Cements: Targeting Therapeutic Release Thresholds for Strontium. J Funct Biomater 2017; 8:jfb8030028. [PMID: 28708123 PMCID: PMC5618279 DOI: 10.3390/jfb8030028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [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: 05/31/2017] [Revised: 07/07/2017] [Accepted: 07/10/2017] [Indexed: 01/25/2023] Open
Abstract
We examine the feasibility and functionality of hydrophilic modifications to a borate glass reinforced resin composite; with the objective of meeting and maintaining therapeutic thresholds for Sr release over time, as a potential method of incorporating antiosteoporotic therapy into a vertebroplasty material. Fifteen composites were formulated with the hydrophilic agent hydroxyl ethyl methacrylate (HEMA, 15, 22.5, 30, 37.5 or 45 wt% of resin phase) and filled with a borate glass (55, 60 or 65 wt% of total cement) with known Sr release characteristics. Cements were examined with respect to degree of cure, water sorption, Sr release, and biaxial flexural strength over 60 days of incubation in phosphate buffered saline. While water sorption and glass degradation increased with increasing HEMA content, Sr release peaked with the 30% HEMA compositions, scanning electron microscope (SEM) imaging confirmed the surface precipitation of a Sr phosphate compound. Biaxial flexural strengths ranged between 16 and 44 MPa, decreasing with increased HEMA content. Degree of cure increased with HEMA content (42 to 81%), while no significant effect was seen on setting times (209 to 263 s). High HEMA content may provide a method of increasing monomer conversion without effect on setting reaction, providing sustained mechanical strength over 60 days.
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Affiliation(s)
- Kathleen MacDonald
- School of Biomedical Engineering, Dalhousie University, Halifax, NS B3H 1X7, Canada.
| | - Richard B Price
- Department of Dental Clinical Sciences, Dalhousie University, Halifax, NS B3H 1X7, Canada.
- Department Applied Oral Sciences, Dalhousie University, Halifax, NS B3H 1X7, Canada.
| | - Daniel Boyd
- School of Biomedical Engineering, Dalhousie University, Halifax, NS B3H 1X7, Canada.
- Department Applied Oral Sciences, Dalhousie University, Halifax, NS B3H 1X7, Canada.
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18
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Wright A, Clark A, Ward G, Moodie F, Taylor G, Boyd D, Currie W, Hislop W, Halsnad S. Alcohol misuse—a national pandemic: an investigation to identify whether implementing an alcohol brief intervention service would benefit patients attending an oral and maxillofacial (OMFS) department. Public Health 2017; 145:20-22. [DOI: 10.1016/j.puhe.2016.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 10/20/2022]
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19
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Kehoe S, El-Khazen Dupuis J, Michaud F, Bigot A, Boyd D, Abraham R, Soulez G. Multimodal “imageable” embolic microspheres: A preliminary study on occlusion effectiveness, level of occlusion, and arterial distribution in a swine liver model. J Vasc Interv Radiol 2017. [DOI: 10.1016/j.jvir.2016.12.602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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20
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Dickey B, Price R, Boyd D. Exploring the unexpected influence of the Si:Ge ratio on the molecular architecture and mechanical properties of Al-free GICs. J Biomater Appl 2016; 31:730-742. [DOI: 10.1177/0885328216672947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Germanium (Ge)-based glass ionomer cements have demonstrated the ability to balance strength with extended setting times, a unique set of characteristics for aluminum-free glass ionomer cements. However, the mechanical properties of current Ge-based glass ionomer cements significantly deteriorate over time, which jeopardizes their clinical potential. This work explores the effect of incrementally decreasing the Si:Ge ratio in the glass phase of zinc-silicate glass ionomer cements to identify potential mechanisms responsible for the time-induced mechanical instability of Ge-based glass ionomer cements. The influence of Ge was evaluated on the basis of changes in mechanical properties and molecular architecture of the cements over a 180-day period. It was observed that the compressive strength and modulus of the cements were sustained when Si:Ge ratios were ≥1:1, but when Si:Ge ratios are <1:1 these properties decreased significantly over time. These mechanical changes were independent of structural changes in the glass ionomer cement matrices, as the level of metal–carboxylate crosslinks remained constant over time across the various Si:Ge ratios explored. However, it was noted the temporal decline of mechanical properties was proportional to the increased release of degradation byproducts, in particular Ge that was released from the cements in substantially greater quantities than other glass constituents. Unexpectedly, the slowest setting cement (Si:Ge 1:1) was also the strongest; behavior that is uncommon in Si-based glass ionomer cements, supports the potential of Ge-containing glass ionomer cements as injectable bone cements in applications such as percutaneous vertebroplasty.
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O'Connell K, Pierlot C, O'Shea H, Beaudry D, Chagnon M, Assad M, Boyd D. Host responses to a strontium releasing high boron glass using a rabbit bilateral femoral defect model. J Biomed Mater Res B Appl Biomater 2016; 105:1818-1827. [PMID: 27219680 DOI: 10.1002/jbm.b.33694] [Citation(s) in RCA: 12] [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] [Received: 01/14/2016] [Revised: 03/30/2016] [Accepted: 04/06/2016] [Indexed: 11/09/2022]
Abstract
Borate glasses have shown promising potential as bioactive materials. With recent research demonstrating that glass properties may be modulated by appropriate compositional design. This may provide for indication specific material characteristics and controlled release of therapeutic inorganic ions (i.e., strontium); controlling such release is critical in order to harness the therapeutic potential. Within this sub-chronic pilot study, a rabbit long-bone model was utilized to explore the safety and efficacy of a high borate glass (LB102: 70B2 O3 -20SrO-6Na2 O-4La2 O3 ) particulate (90 - 710 μm) for bone regeneration. Six bilateral full-thickness defects (Ø = 3.5 mm; L = 8 mm) were created in three white New Zealand rabbits. Longitudinal non-decalcified sections of each defect site were produced and stained with Goldner's Trichrome. Histopathological examination revealed that LB102 demonstrated osteoconductive and osseointegrative properties with greater new bone being formed within and surrounding LB102 particles, when compared to the sham control. The inflammatory cell infiltration was observed to be slightly higher in the control when compared to LB102 defect sites, while no significant difference in fibrosis and neovascularization was determined, indicating that healing was occurring in a normal fashion. These data further suggest the possible utility of high borate glasses with appropriate compositional design for medical applications, such as bone augmentation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1818-1827, 2017.
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Affiliation(s)
- Kathleen O'Connell
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland
| | - Caitlin Pierlot
- Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, Canada
| | - Helen O'Shea
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland
| | - Diane Beaudry
- Orthopedics and Biomaterials Lab, AccelLAB Inc., Boisbriand, QC, Canada
| | - Madeleine Chagnon
- Orthopedics and Biomaterials Lab, AccelLAB Inc., Boisbriand, QC, Canada
| | - Michel Assad
- Orthopedics and Biomaterials Lab, AccelLAB Inc., Boisbriand, QC, Canada
| | - Daniel Boyd
- Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, Canada.,School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
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Nair P, Al-Soufi S, Lowe D, Behan D, Harkess M, Breeding J, Boyd D, Dhital K, Spratt P, Glanville A. Peri-Operative Transfusion Practices in Lung Transplant Patients. J Heart Lung Transplant 2016. [DOI: 10.1016/j.healun.2016.01.662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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23
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Sharmin N, Hasan MS, Rudd CD, Boyd D, Werner-Zwanziger U, Ahmed I, Parsons AJ. Effect of boron oxide addition on the viscosity-temperature behaviour and structure of phosphate-based glasses. J Biomed Mater Res B Appl Biomater 2016; 105:764-777. [PMID: 26748481 DOI: 10.1002/jbm.b.33610] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [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: 07/24/2015] [Revised: 12/03/2015] [Accepted: 12/08/2015] [Indexed: 11/07/2022]
Abstract
In this study, nine phosphate-based glass formulations from the system P2 O5 -CaO-Na2 O-MgO-B2 O3 were prepared with P2 O5 content fixed as 40, 45 and 50 mol%, where Na2 O was replaced by 5 and 10 mol% B2 O3 and MgO and CaO were fixed to 24 and 16 mol%, respectively. The effect of B2 O3 addition on the viscosity-temperature behaviour, fragility index and structure of the glasses was investigated. The composition of the glasses was confirmed by ICP-AES. The viscosity-temperature behaviour of the glasses were measured using beam-bending and parallel -plate viscometers. The viscosity of the glasses investigated was found to shift to higher temperature with increasing B2 O3 content. The kinetic fragility parameter, m and F1/2 , estimated from the viscosity curve were found to decease with increasing B2 O3 content. The structural analysis was achieved by a combination of Fourier transform infrared spectroscopy and solid state nuclear magnetic resonance. 31 P solid-state magic-angle-spinning nuclear magnetic resonance (MAS-NMR) showed that the local structure of the glasses changes with increasing B2 O3 content. As B2 O3 was added to the glass systems, the phosphate connectivity increases as the as the Q1 units transforms into Q2 units. The 11 B NMR results confirmed the presence of tetrahedral boron (BO4 ) units for all the compositions investigated. Structural analysis indicates an increasing level of cross-linking with increasing B2 O3 content. Evidence of the presence of P-O-B bonds was also observed from the FTIR and 31 P NMR analysis. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 764-777, 2017.
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Affiliation(s)
- Nusrat Sharmin
- Division of Materials, Mechanics and Structures, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Muhammad S Hasan
- Purac Biomaterials, 5150 N Royal Atlanta DR., Tucker, Georgia, 30084
| | - Chris D Rudd
- Division of Materials, Mechanics and Structures, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Daniel Boyd
- Department of Applied Oral Sciences, Faculty of Dentistry, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | | | - Ifty Ahmed
- Division of Materials, Mechanics and Structures, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Andrew J Parsons
- Division of Materials, Mechanics and Structures, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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Kilcup N, Gaynard S, Werner-Zwanziger U, Tonkopi E, Hayes J, Boyd D. Stimulation of apoptotic pathways in liver cancer cells: An alternative perspective on the biocompatibility and the utility of biomedical glasses. J Biomater Appl 2015; 30:1445-59. [DOI: 10.1177/0885328215621663] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A host of research opportunities with innumerable clinical applications are open to biomedical glasses if one considers their potential as therapeutic inorganic ion delivery systems. Generally, applications have been limited to repair and regeneration of hard tissues while compositions are largely constrained to the original bioactive glass developed in the 1960s. However, in oncology applications the therapeutic paradigm shifts from repair to targeted destruction. With this in mind, the composition–structure–property–function relationships of vanadium-containing zinc-silicate glasses (0.51SiO2–0.29Na2O–(0.20- X)ZnO– XV2O5, 0 ≤ X ≤ 0.09) were characterized in order to determine their potential as therapeutic inorganic ion delivery systems. Increased V2O5 mole fraction resulted in a linear decrease in density and glass transition temperature (Tg). 29Si MAS NMR peak maxima shifted upfield while 51V MAS NMR peak maxima were independent of V2O5 content and overlapped well with the spectra NaVO3. Increased V2O5 mole fraction caused ion release to increase. When human liver cancer cells, HepG2, were exposed to these ions they demonstrated a concentration-dependent cytotoxic response, mediated by apoptosis. This work demonstrates that the zinc-silicate system studied herein is capable of delivering therapeutic inorganic ions at concentrations that induce apoptotic cell death and provide a simple means to control therapeutic inorganic ion delivery.
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Affiliation(s)
- Nancy Kilcup
- School of Biomedical Engineering, Dalhousie University, Halifax, Canada
| | - Seán Gaynard
- Regenerative Medicine Institute, Bioscience Research Building, National University of Ireland Galway, Galway, Ireland
| | - Ulrike Werner-Zwanziger
- Department of Chemistry and Institute for Research in Materials, Dalhousie University, Halifax, Canada
| | - Elena Tonkopi
- Department of Diagnostic Imaging and Interventional Radiology, QEII Health Sciences Centre, Victoria General Hospital, Victoria Building, Halifax, Canada
- Department of Diagnostic Radiology, Dalhousie University, Halifax, Canada
| | - Jessica Hayes
- Regenerative Medicine Institute, Bioscience Research Building, National University of Ireland Galway, Galway, Ireland
| | - Daniel Boyd
- School of Biomedical Engineering, Dalhousie University, Halifax, Canada
- Department of Diagnostic Imaging and Interventional Radiology, QEII Health Sciences Centre, Victoria General Hospital, Victoria Building, Halifax, Canada
- Department of Applied Oral Sciences, Dentistry Building, Dalhousie University, Halifax, Canada
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Konstantatos AH, Howard W, Story D, Mok LYH, Boyd D, Chan MTV. A randomised controlled trial of peri-operative pregabalin vs. placebo for video-assisted thoracoscopic surgery. Anaesthesia 2015; 71:192-7. [DOI: 10.1111/anae.13292] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2015] [Indexed: 12/31/2022]
Affiliation(s)
- A. H. Konstantatos
- Department of Anaesthesia and Peri-operative Medicine; Alfred Hospital; Melbourne Victoria Australia
| | - W. Howard
- Department of Anaesthesia; Austin Hospital; Melbourne Victoria Australia
| | - D. Story
- Anaesthesia, Peri-operative and Pain Medicine Unit; Melbourne Medical School; The University of Melbourne; Melbourne Victoria Australia
| | - L. Y. H. Mok
- Department of Anaesthesia and Intensive Care; The Chinese University of Hong Kong; Prince of Wales Hospital; Shatin Hong Kong China
| | - D. Boyd
- Department of Anaesthesia and Peri-operative Medicine; Alfred Hospital; Melbourne Victoria Australia
| | - M. T. V. Chan
- Department of Anaesthesia and Intensive Care; The Chinese University of Hong Kong; Prince of Wales Hospital; Shatin Hong Kong China
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Halsnad M, Moodie F, Boyd D, White J. Extensive osteolysis of the maxillofacial skeleton – a case report & review of literature. Int J Oral Maxillofac Surg 2015. [DOI: 10.1016/j.ijom.2015.08.588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Placek LM, Keenan TJ, Li Y, Yatongchai C, Pradhan D, Boyd D, Mellott NP, Wren AW. Investigating the effect of TiO2on the structure and biocompatibility of bioactive glass. J Biomed Mater Res B Appl Biomater 2015; 104:1703-1712. [DOI: 10.1002/jbm.b.33521] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 08/04/2015] [Accepted: 08/23/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Lana M. Placek
- Inamori School of Engineering; Alfred University; Alfred New York
| | | | - Yiming Li
- Inamori School of Engineering; Alfred University; Alfred New York
| | | | - Dimple Pradhan
- Inamori School of Engineering; Alfred University; Alfred New York
| | - Daniel Boyd
- Department of Applied Oral Sciences; Dalhousie University; Halifax Nova Scotia Canada
| | | | - Anthony W. Wren
- Inamori School of Engineering; Alfred University; Alfred New York
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Partain L, Kwon J, Rottmann J, Zentai G, Berbeco R, Boyd D. SU-E-J-56: Static Gantry Digital Tomosynthesis From the Beam's-Eye-View. Med Phys 2015. [DOI: 10.1118/1.4924143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Kiri L, Filiaggi M, Boyd D. Methotrexate-loaded glass ionomer cements for drug release in the skeleton: An examination of composition-property relationships. J Biomater Appl 2015; 30:732-9. [PMID: 25940017 DOI: 10.1177/0885328215584294] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chemotherapeutic-loaded bone cement may be an effective method of drug delivery for the management of cancer-related vertebral fractures that require cement injection for pain relief. Recent advancements in the development of aluminum-free glass ionomer cements (GICs) have rendered this class of biomaterials clinically viable for such applications. To expand the therapeutic benefits of these materials, this study examined, for the first time, their drug delivery potential. Through incrementally loading the GIC with methotrexate (MTX) by up to 10-wt%, composition-property relationships were established, correlating MTX loading with working time and setting time, as well as compressive strength, drug release, and cytotoxic effect over 31 days. The most significant finding of this study was that MTX was readily released from the GIC, while maintaining cytotoxic activity. Release correlated linearly with initial loading and appeared to be diffusion mediated, delivering a total of 1-2% of the incorporated drug. MTX loading in this range exerted minimal effects to handling and strength, indicating the clinical utility of the material was not compromised by MTX loading. The MTX-GIC systems examined herein are promising materials for combined structural delivery applications.
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Affiliation(s)
- Lauren Kiri
- Department of Applied Oral Sciences, Dalhousie University, Canada
| | - Mark Filiaggi
- Department of Applied Oral Sciences, Dalhousie University, Canada School of Biomedical Engineering, Dalhousie University, Canada
| | - Daniel Boyd
- Department of Applied Oral Sciences, Dalhousie University, Canada School of Biomedical Engineering, Dalhousie University, Canada
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Kiri L, Boyd D. Predicting composition-property relationships for glass ionomer cements: a multifactor central composite approach to material optimization. J Mech Behav Biomed Mater 2015; 46:285-91. [PMID: 25828159 DOI: 10.1016/j.jmbbm.2015.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [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: 12/02/2014] [Revised: 02/06/2015] [Accepted: 02/09/2015] [Indexed: 11/29/2022]
Abstract
Adjusting powder-liquid ratio (P/L) and polyacrylic acid concentration (AC) has been documented as a means of tailoring the handling and mechanical properties of glass ionomer cements (GICs). This work implemented a novel approach in which the interactive effects of these two factors on three key GIC properties (working time, setting time, and compressive strength) were investigated using a central composite design of experiments. Using nonlinear regression analysis, formulation-property relationships were derived for each property, which enabled prediction of an optimal formulation (P/L and AC) through application of the desirability approach. A novel aluminum free GIC was investigated, as this material may present the first clinically viable GIC for use in injectable spinal applications, such as vertebroplasty. Ultimately, this study presents the first series of predictive regression models that explain the formulation-dependence of a GIC, and the first statistical method for optimizing both P/L and AC depending on user-defined inputs.
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Affiliation(s)
- Lauren Kiri
- Department of Applied Oral Sciences, Dalhousie University, 5981 University Avenue, Halifax, NS, Canada B3H 4R2.
| | - Daniel Boyd
- Department of Applied Oral Sciences, Dalhousie University, 5981 University Avenue, Halifax, NS, Canada B3H 4R2; School of Biomedical Engineering, Dalhousie University, 5981 University Avenue, Halifax, NS, Canada B3H 4R2.
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Kilcup N, Tonkopi E, Abraham RJ, Boyd D, Kehoe S. Composition-property relationships for radiopaque composite materials: pre-loaded drug-eluting beads for transarterial chemoembolization. J Biomater Appl 2015; 30:93-103. [PMID: 25690386 DOI: 10.1177/0885328215572196] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The purpose of this study was to synthesize and optimize intrinsically radiopaque composite embolic microspheres for sustained release of doxorubicin in drug-eluting bead transarterial chemoembolization. Using a design of experiments approach, 12 radiopaque composites composed of polylactic-co-glycolic acid and a radiopaque glass (ORP5) were screened over a range of compositions and examined for radiopacity (computed tomography) and density. In vitro cell viability was determined using an extract assay derived from each composition against the human hepatocellular carcinoma cell line, HepG2. Mathematical models based on a D-Optimal response surface methodology were used to determine the preferred radiopaque composite. The resulting radiopaque composite was validated and subsequently loaded with doxorubicin between 0 and 1.4% (wt% of polylactic-co-glycolic acid) to yield radiopaque composite drug-eluting beads. Thereafter, the radiopaque composite drug-eluting beads were subjected to an elution study (up to 168 h) to determine doxorubicin release profiles (UV-Vis spectroscopy) and in vitro cell viability. Radiopaque composites evaluated for screening purposes had densities between 1.28 and 1.67 g.cm(-3), radiopacity ranged between 211 and 1450HU and cell viabilities between 91 and 106% were observed. The optimized radiopaque composite comprised 23 wt% polylactic-co-glycolic acid and 60 wt% ORP5 with a corresponding density of 1.63 ± 0.001 g.cm(-3), radiopacity at 1930 ± 44HU and cell viability of 89 ± 7.6%. Radiopaque composite drug-eluting beads provided sustained doxorubicin release over 168 h. In conclusion, the mathematical models allowed for the identification and synthesis of a unique radiopaque composite. The optimized radiopaque composite had similar density and cell viability to commercially available embolic microspheres. It was possible to preload doxorubicin into radiopaque composite drug-eluting beads, such that sustained release was possible under simulated physiological conditions.
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Affiliation(s)
- Nancy Kilcup
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - Elena Tonkopi
- Department of Diagnostic Imaging and Interventional Radiology, QE II Health Sciences Centre, Halifax, NS, Canada
| | - Robert J Abraham
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada Department of Diagnostic Imaging and Interventional Radiology, QE II Health Sciences Centre, Halifax, NS, Canada ABK Biomedical Inc., Halifax, NS, Canada
| | - Daniel Boyd
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada Department of Diagnostic Imaging and Interventional Radiology, QE II Health Sciences Centre, Halifax, NS, Canada Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, Canada ABK Biomedical Inc., Halifax, NS, Canada
| | - Sharon Kehoe
- Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, Canada ABK Biomedical Inc., Halifax, NS, Canada
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Abraham R, Basseri H, Davis C, Tonkopi E, Kehoe S, Boyd D, Bowen C. Magnetic resonance imaging characteristics of imageable embolic microspheres. J Vasc Interv Radiol 2015. [DOI: 10.1016/j.jvir.2014.12.222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Kehoe S, Amensag S, Looney M, Abraham RJ, Boyd D. "Imageable" Zinc-Silicate Glass Microspheres For Transarterial Embolization: A Renal Artery Embolization Study. Biomedical glasses 2015. [DOI: 10.1515/bglass-2015-0007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractIntrinsically radiopaque (imageable) microspheres for transarterial embolization (TAE) are required to enable real-time intraprocedural feedback and definition of spatial distribution patterns of embolic materials in target tissues. This pilot study evaluates acute and sub-chronic safety and efficacy of imageable zinc-silicate (Zn-Si) glass microspheres in a swine renal artery embolization (RAE) model. Eight swine were divided into two cohorts. Clinical determinants of embolization effectiveness, including imageability, deliverability and temporal/ spatial distribution of microspheres in target tissues were assessed. Subsequently, cohort I and II were used to evaluate the acute and subchronic host response against the Zn-Si microspheres versus a clinical control. The developed microspheres provide for direct intraprocedural feedback using standard diagnostic imaging techniques. Fluoroscopy correlated with ex-vivo high-resolution radiography, CT and micro-CT, demonstrating high imageability, excellent spatial distribution and packing of the Zn- Si microspheres. At follow-up, infarction of the embolized kidneys was noted without any major adverse tissue reaction. Mild recanalization was observed microscopically for both experimental and control microspheres. Zn-Si microspheres permit the definition of spatial distribution in a target tissue, consequently permitting the optimization, personalization and improvement of TAE techniques.
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Valliant EM, Gagnier D, Dickey BT, Boyd D, Joseph Filiaggi M. Calcium polyphosphate as an additive to zinc-silicate glass ionomer cements. J Biomater Appl 2015; 30:61-70. [DOI: 10.1177/0885328215568985] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Aluminum-free glass ionomer cements (GICs) are under development for orthopedic applications, but are limited by their insufficient handling properties. Here, the addition of calcium polyphosphate (CPP) was investigated as an additive to an experimental zinc-silicate glass ionomer cement. A 50% maximum increase in working time was observed with CPP addition, though this was not clinically significant due to the short working times of the starting zinc-silicate GIC. Surprisingly, CPP also improved the mechanical properties, especially the tensile strength which increased by ∼33% after 30 days in TRIS buffer solution upon CPP addition up to 37.5 wt%. This strengthening may have been due to the formation of ionic crosslinks between the polyphosphate chains and polyacrylic acid. Thus, CPP is a potential additive to future GIC compositions as it has been shown to improve handling and mechanical properties. In addition, CPP may stimulate new bone growth and provide the ability for drug delivery, which are desirable modifications for an orthopedic cement.
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Affiliation(s)
- Esther Mae Valliant
- Department of Applied Oral Sciences, Dalhousie University, 5981 University Avenue, Halifax, Nova Scotia, B3H 4R2, Canada
| | - David Gagnier
- Department of Applied Oral Sciences, Dalhousie University, 5981 University Avenue, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Brett Thomas Dickey
- Department of Applied Oral Sciences, Dalhousie University, 5981 University Avenue, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Daniel Boyd
- Department of Applied Oral Sciences, Dalhousie University, 5981 University Avenue, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Mark Joseph Filiaggi
- Department of Applied Oral Sciences, Dalhousie University, 5981 University Avenue, Halifax, Nova Scotia, B3H 4R2, Canada
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Hasan MS, Werner-Zwanziger U, Boyd D. Composition-structure-properties relationship of strontium borate glasses for medical applications. J Biomed Mater Res A 2014; 103:2344-54. [PMID: 25366812 DOI: 10.1002/jbm.a.35361] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [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: 08/21/2014] [Revised: 10/15/2014] [Accepted: 10/22/2014] [Indexed: 11/06/2022]
Abstract
We have synthesized TiO2 doped strontium borate glasses, 70B2O3-(30-x)SrO-xTiO2 and 70B2 O3 -20SrO(10-x)Na2 O-xTiO2 . The composition dependence of glass structure, density, thermal properties, durability, and cytotoxicity of degradation products was studied. Digesting the glass in mineral acid and detecting the concentrations of various ions using an ICP provided the actual compositions that were 5-8% deviated from the theoretical values. The structure was investigated by means of (11)B magic angle spinning (MAS) NMR spectroscopy. DSC analyses provided the thermal properties and the degradation rates were measured by measuring the weight loss of glass disc-samples in phosphate buffered saline at 37°C in vitro. Finally, the MTT assay was used to analyze the cytotoxicity of the degradation products. The structural analysis revealed that replacing TiO2 for SrO or Na2 O increased the BO3/BO4 ratio suggesting the network-forming role of TiO2 . Thermal properties, density, and degradation rates also followed the structural changes. Varying SrO content predominantly controlled the degradation rates, which in turn controlled the ion release kinetics. A reasonable control (2-25% mass loss in 21 days) over mass loss was achieved in current study. Even though, very high concentrations (up to 5500 ppm B, and 1200 ppm Sr) of ions were released from the ternary glass compositions that saturated the degradation media in 7 days, the degradation products from ternary glass system was found noncytotoxic. However, quaternary glasses demonstrated negative affect on cell viability due to very high (7000 ppm) Na ion concentration. All the glasses investigated in current study are deemed fast degrading with further control over degradation rates, release kinetics desirable.
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Affiliation(s)
- Muhammad S Hasan
- Department of Applied Oral Sciences, School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ulrike Werner-Zwanziger
- Department of Chemistry and Institute for Research in Materials, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Daniel Boyd
- Department of Applied Oral Sciences, School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
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Hasan MS, Kehoe S, Boyd D. Temporal analysis of dissolution by-products and genotoxic potential of spherical zinc-silicate bioglass: "imageable beads" for transarterial embolization. J Biomater Appl 2014; 29:566-81. [PMID: 24913613 DOI: 10.1177/0885328214537694] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Embolization of vascular tumors is an important tool in minimally invasive surgical intervention. Radiopaque, non-degradable, and non-deformable spherical zinc-silicate glass particles were produced in a range of 45-500 μm. Three size ranges (45-150, 150-300, and 300-500 μm) were used in the current study. The glass microspheres were eluted in polar (saline solution) and non-polar (dimethyl sulfoxide) medium, and ion release profiles were recorded using inductively coupled plasma atomic emission spectroscopy. Approximately 80% of Gaussian distribution was achieved by simple sieving. The ions released from the microspheres were dependent upon surface area to volume ratio as well as the nature of elution media. Greater ions were released from smaller particles (45-150 μm) having largest surface area in polar medium. For the genotoxicity bacterial mutation Ames assay, the concentrations of all the ions were well below their therapeutic concentration reported in the literature. No mutagenic effect was observed in the bacterial mutation Ames test. Hence, it can be concluded that the glass microspheres produced herein are non-mutagenic further supporting the materials potential as a suitable embolic agent.
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Affiliation(s)
- M S Hasan
- Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, Canada School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - S Kehoe
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - D Boyd
- Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, Canada School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada ABK Biomedical Inc., Halifax, Canada
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Hossain KMZ, Hasan MS, Boyd D, Rudd CD, Ahmed I, Thielemans W. Effect of cellulose nanowhiskers on surface morphology, mechanical properties, and cell adhesion of melt-drawn polylactic Acid fibers. Biomacromolecules 2014; 15:1498-506. [PMID: 24725085 DOI: 10.1021/bm5001444] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Polylactic acid (PLA) fibers were produced with an average diameter of 11.2 (± 0.9) μm via a melt-drawing process. The surface of the PLA fibers was coated with blends of cellulose nanowhiskers (CNWs) (65 to 95 wt %) and polyvinyl acetate (PVAc). The CNWs bound to the smooth PLA fiber surface imparted roughness, with the degree of roughness depending on the coating blend used. The fiber tensile modulus increased 45% to 7 GPa after coating with 75 wt % CNWs compared with the uncoated PLA fibers, and a significant increase in the fiber moisture absorption properties at different humidity levels was also determined. Cytocompatibility studies using NIH-3T3 mouse fibroblast cells cultured onto CNWs-coated PLA surface revealed improved cell adhesion compared with the PLA control, making this CNW surface treatment applicable for biomedical and tissue engineering applications. Initial studies also showed complete cell coverage within 2 days.
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Affiliation(s)
- Kazi M Zakir Hossain
- Division of Materials, Mechanics and Structures, Faculty of Engineering, ‡School of Chemistry, and §Process and Environmental Research Division, Faculty of Engineering, University of Nottingham , University Park, Nottingham NG7 2RD, United Kingdom
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Kilcup N, Kehoe S, Tonkopi E, Abraham R, Boyd D. Synthesis and evaluation of a pre-loaded drug eluting radiopaque composite embolic microsphere (CEM) for transarterial chemoembolization (TACE). J Vasc Interv Radiol 2014. [DOI: 10.1016/j.jvir.2013.12.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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39
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Mataseje LF, Boyd DA, Lefebvre B, Bryce E, Embree J, Gravel D, Katz K, Kibsey P, Kuhn M, Langley J, Mitchell R, Roscoe D, Simor A, Taylor G, Thomas E, Turgeon N, Mulvey MR, Boyd D, Bryce E, Conly J, Deheer J, Embil J, Embree J, Evans G, Forgie S, Frenette C, Lemieux C, Golding G, Gravel D, Henderson E, Hutchinson J, John M, Johnston L, Katz K, Kibsey P, Kuhn M, Langley J, Lesaux N, Loeb M, Matlow A, McGeer A, Miller M, Mitchell R, Moore D, Mounchili A, Mulvey M, Pelude L, Roth V, Simor A, Suh K, Taylor G, Thomas E, Turgeon N, Vearncombe M, Vayalumkal J, Weiss K, Wong A. Complete sequences of a novel blaNDM-1-harbouring plasmid from Providencia rettgeri and an FII-type plasmid from Klebsiella pneumoniae identified in Canada. J Antimicrob Chemother 2013; 69:637-42. [DOI: 10.1093/jac/dkt445] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Alhalawani AM, Curran DJ, Pingguan-Murphy B, Boyd D, Towler MR. A Novel Glass Polyalkenoate Cement for Fixation and Stabilisation of the Ribcage, Post Sternotomy Surgery: An ex-Vivo Study. J Funct Biomater 2013; 4:329-57. [PMID: 24956193 PMCID: PMC4030933 DOI: 10.3390/jfb4040329] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 10/25/2013] [Accepted: 11/12/2013] [Indexed: 11/16/2022] Open
Abstract
This study investigates the use of gallium (Ga) based glass polyalkenoate cements (GPCs) as a possible alternative adhesive in sternal fixation, post sternotomy surgery. The glass series consists of a Control (CaO-ZnO-SiO2), and LGa-1 and LGa-2 which contain Ga at the expense of zinc (Zn) in 0.08 mol% increments. The additions of Ga resulted in increased working time (75 s to 137 s) and setting time (113 to 254 s). Fourier Transform Infrared (FTIR) analysis indicated that this was a direct result of increased unreacted poly(acrylic acid) (PAA) and the reduction of crosslink formation during cement maturation. LGa samples (0.16 wt % Ga) resulted in an altered ion release profile, particularly for 30 days analysis, with maximum Ca2+, Zn2+, Si4+ and Ga3+ ions released into the distilled water. The additions of Ga resulted in increased roughness and decreased contact angles during cement maturation. The presence of Ga has a positive effect on the compressive strength of the samples with strengths increasing over 10 MPa at 7 days analysis compared to the 1 day results. The additions of Ga had relatively no effect on the flexural strength. Tensile testing of bovine sterna proved that the LGa samples (0.16 wt % Ga) are comparable to the Control samples.
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Affiliation(s)
- Adel M.F. Alhalawani
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia; E-Mails: (A.M.F.A.); (B.P.-M.)
| | - Declan J. Curran
- Department of Mechanical & Industrial Engineering, Ryerson University, Toronto M5B 2K3, ON, Canada; E-Mail:
| | - Belinda Pingguan-Murphy
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia; E-Mails: (A.M.F.A.); (B.P.-M.)
| | - Daniel Boyd
- Department of Applied Oral Sciences, Faculty of Dentistry, Dalhousie University, Halifax B3H 4R2, NS, Canada; E-Mail:
| | - Mark R. Towler
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia; E-Mails: (A.M.F.A.); (B.P.-M.)
- Department of Mechanical & Industrial Engineering, Ryerson University, Toronto M5B 2K3, ON, Canada; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-416-979-5000 (ext. 4518)
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Abstract
INTRODUCTION Lemierre's syndrome is a potentially fatal condition characterised by spread of an oropharyngeal infection, resulting in thrombosis of the internal jugular vein. This leads to septicaemia and possible metastatic abscesses. CASE PRESENTATION We discuss the case of a previously healthy 17-year-old male who developed Lemierre's syndrome following dental sepsis. He presented with bilateral submandibular and submental swelling extending into the neck and chest. His management included a tracheostomy; incision and drainage of the abscesses; drainage of a pleural effusion and prolonged anticoagulant therapy. CONCLUSION The incidence of Lemierre's disease appears to be increasing and early diagnosis is essential. A high index of suspicion is needed in cases of oropharyngeal infection followed by fever, tender swelling of the neck and dysphagia - especially in young patients.
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Affiliation(s)
- D Boyd
- Oral and Maxillofacial Surgery Department, Monklands Hospital, UK
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Kiaii B, Stephanie F, Swinamer S, Rayman R, Dobkowski W, Iglesias I, Bainbridge D, Harle C, Murkin J, Chu M, Boyd D, Menkis A. 14 Year Experience With Robotic Assisted Surgical Coronary Artery Revascularization With Postoperative Cardiac Catheterization. Can J Cardiol 2013. [DOI: 10.1016/j.cjca.2013.07.405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Kehoe S, Tremblay ML, Coughlan A, Towler MR, Rainey JK, Abraham RJ, Boyd D. Preliminary investigation of the dissolution behavior, cytocompatibility, effects of fibrinogen conformation and platelet adhesion for radiopaque embolic particles. J Funct Biomater 2013; 4:89-113. [PMID: 24956083 PMCID: PMC4030908 DOI: 10.3390/jfb4030089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [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: 01/11/2013] [Revised: 05/06/2013] [Accepted: 06/08/2013] [Indexed: 12/18/2022] Open
Abstract
Experimental embolic particles based on a novel zinc-silicate glass system have been biologically evaluated for potential consideration in transcatheter arterial embolization procedures. In addition to controlling the cytotoxicity and haemocompatibility for such embolic particles, its glass structure may mediate specific responses via dissolution in the physiological environment. In a 120 h in-vitro dissolution study, ion release levels for silicon (Si4+), sodium (Na+), calcium (Ca2+), zinc (Zn2+), titanium (Ti4+), lanthanum (La3+), strontium (Sr2+), and magnesium (Mg2+), were found to range from 0.04 to 5.41 ppm, 0.27-2.28 ppm, 2.32-8.47 ppm, 0.16-0.20 ppm, 0.12-2.15 ppm, 0.16-0.49 ppm and 0.01-0.12 ppm, respectively for the series of glass compositions evaluated. Initial release of Zn2+ (1.93-10.40 ppm) was only evident after 120 h. All compositions showed levels of cell viabilities ranging from 61.31 ± 4.33% to 153.7 ± 1.25% at 25%-100% serial extract dilutions. The conformational state of fibrinogen, known to induce thrombi, indicated that no changes were induced with respect of the materials dissolution by-products. Furthermore, the best-in-class experimental composition showed equivalency to contour PVA in terms of inducing platelet adhesion. The data generated here provides requisite evidence to continue to in-vivo pre-clinical evaluation using the best-in-class experimental composition evaluated.
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Affiliation(s)
- Sharon Kehoe
- Department of Applied Oral Sciences, Dalhousie University, PO Box 15000, Halifax, NS B3H 4R2, Canada.
| | | | - Aisling Coughlan
- Inamori School of Engineering, Alfred University, Alfred, NY 14802, USA.
| | - Mark R Towler
- Faculty of Engineering & Architectural Science, Ryerson University, 350 Victoria Street, Toronto, ON, M5B 2K3, Canada.
| | - Jan K Rainey
- Department of Biochemistry & Molecular Biology, Dalhousie University, NS, B3H 4R2, Canada.
| | - Robert J Abraham
- Department of Diagnostic Imaging and Interventional Radiology, QE II Health Sciences Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada.
| | - Daniel Boyd
- Department of Applied Oral Sciences, Dalhousie University, PO Box 15000, Halifax, NS B3H 4R2, Canada.
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Hong P, Boyd D, Beyea SD, Bezuhly M. Enhancement of bone consolidation in mandibular distraction osteogenesis: A contemporary review of experimental studies involving adjuvant therapies. J Plast Reconstr Aesthet Surg 2013; 66:883-95. [DOI: 10.1016/j.bjps.2013.03.030] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 02/14/2013] [Accepted: 03/16/2013] [Indexed: 11/28/2022]
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Dickey BT, Kehoe S, Boyd D. Novel adaptations to zinc-silicate glass polyalkenoate cements: the unexpected influences of germanium based glasses on handling characteristics and mechanical properties. J Mech Behav Biomed Mater 2013; 23:8-21. [PMID: 23648365 DOI: 10.1016/j.jmbbm.2013.03.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 03/13/2013] [Accepted: 03/17/2013] [Indexed: 11/19/2022]
Abstract
Aluminum-free glass polyalkenoate cements (GPC) have been hindered for use as injectable bone cements by their inability to balance handling characteristics with mechanical integrity. Currently, zinc-based, aluminum-free GPCs demonstrate compression strengths in excess of 60MPa, but set in c. 1-2 min. Previous efforts to extend the setting reaction have remained clinically insufficient and are typically accompanied by a significant drop in strength. This work synthesized novel glasses based on a zinc silicate composition with the inclusion of GeO2, ZrO2, and Na2O, and evaluated the setting reaction and mechanical properties of the resultant GPCs. Germanium based GPCs were found to have working times between 5 and 10 min, setting times between 14 and 36 min, and compression strengths in excess of 30 MPa for the first 30 days. The results of this investigation have shown that the inclusion of GeO2, ZrO2, and Na2O into the glass network have produced, for the first time, an aluminum-free GPC that is clinically viable as injectable bone cements with regards to handling characteristics and mechanical properties.
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Affiliation(s)
- B T Dickey
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
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Dickey B, Saffary J, Dickinson V, Kehoe S, Abraham R, Boyd D. Development and evaluation of an inherently radiopaque, adhesive bone cement for vertebroplasty. J Vasc Interv Radiol 2013. [DOI: 10.1016/j.jvir.2013.01.485] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Kehoe S, Langman M, Werner-Zwanziger U, Abraham RJ, Boyd D. Mixture designs to assess composition–structure–property relationships in SiO2–CaO–ZnO–La2O3–TiO2–MgO–SrO–Na2O glasses: Potential materials for embolization. J Biomater Appl 2012; 28:416-33. [DOI: 10.1177/0885328212455834] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Embolization with micron-sized particulates is widely applied to treat uterine fibroids. The objective of this work was to develop mixture designs to predict materials composition–structure–property relationships for the SiO2–CaO–ZnO–La2O3–TiO2–MgO–SrO–Na2O glass system and compare its fundamental materials properties (density and cytocompatibility), against a state-of-the-art embolic agent (contour polyvinyl alcohol) to assess the potential of these materials for embolization therapies. The glass structures were evaluated using 29Si MAS NMR to identify chemical shift and line width; the particulate densities were determined using helium pycnometry and the cell viabilities were assessed via MTT assay. 29Si MAS NMR results indicated peak maxima for each glass in the range of −82.3 ppm to −89.9 ppm; associated with Q2 to Q3 units in silicate glasses. All experimental embolic compositions showed enhanced in vitro compatibility in comparison to Contour PVA with the exceptions of ORP9 and ORP11 (containing no TiO2). In this study, optimal compositions for cell viability were obtained for the following compositional ranges: 0.095–0.188 mole fraction ZnO; 0.068–0.159 mole fraction La2O3; 0.545–0.562 mole fraction SiO2 and 0.042–0.050 mole fraction TiO2. To ensure ease of producibility in obtaining good melts, a maximum loading of 0.068 mole fraction La2O3 is required. This is confirmed by the desirability approach, for which the only experimental composition (ORP5) of the materials evaluated was presented as an optimum composition; combining high cell viability with ease of production (0.188 mole fraction ZnO; 0.068 mole fraction La2O3; 0.562 mole fraction SiO2 and 0.042 mole fraction TiO2).
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Affiliation(s)
- Sharon Kehoe
- Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - Maxine Langman
- Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, Canada
| | - Ulli Werner-Zwanziger
- Department of Chemistry and Institute for Research in Materials, Dalhousie University, Halifax, NS, Canada
| | - Robert J Abraham
- Department of Diagnostic Imaging and Interventional Radiology, QE II Health Sciences Centre, Dalhousie University, Halifax, NS, Canada
| | - Daniel Boyd
- Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
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Kehoe S, Zhang XF, Lewis L, O'Shea H, Boyd D. Characterization of PLGA based composite nerve guidance conduits: effect of F127 content on modulus over time in simulated physiological conditions. J Mech Behav Biomed Mater 2012; 14:180-5. [PMID: 23026696 DOI: 10.1016/j.jmbbm.2012.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 05/31/2012] [Accepted: 06/07/2012] [Indexed: 11/15/2022]
Abstract
PLGA/pluronic F127 based nerve guidance conduits (NGCs) for peripheral nerve regeneration offer excellent potential for clinical use. To date, little emphasis has been directed towards the effect of pluronic F127 on their subsequent mechanical properties as a function of degradation time or the physiological environment. This report was designed to redress the balance. This study synthesised 5 groups of 20wt% PLGA NGCs with varied additions of pluronic F127 (range 0-5wt%) to obtain Young's Moduli (E) in the range of 7-107MPa, depending on degradation conditions and pluronic F127 content.
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Affiliation(s)
- S Kehoe
- Department of Applied Oral Science, Dalhousie University, P.O. Box 15000, Halifax, NS, Canada B3H 4R2.
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Kehoe S, Abraham R, Tonkopi E, Boyd D. Abstract No. 74: Novel radiopaque embolic agent for uterine fibroid embolization: determination of radiopacity and biological evaluation; cytocompatibility, intracutaneous reactivity and local effects after implantation. J Vasc Interv Radiol 2012. [DOI: 10.1016/j.jvir.2011.12.113] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Looney M, Shea HO, Gunn L, Crowley D, Boyd D. An evaluation of the processing conditions, structure, and properties (biaxial flexural strength and antibacterial efficacy) of sintered strontium–zinc–silicate glass ceramics. J Biomater Appl 2011; 27:937-47. [DOI: 10.1177/0885328211430423] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The use of artificial bone grafts has increased in order to satisfy a growing demand for bone replacement materials. Initial mechanical stability of synthetic bone grafts is very advantageous for certain clinical applications. Coupled with the advantage of mechanical strength, a material with inherent antibacterial properties would be very beneficial. A series of strontium-doped zinc silicate (Ca–Sr–Na–Zn–Si) glass ceramics have been characterized in terms of their crystalline structure, biaxial flexural strength and antibacterial efficacy based on the identification of optimum sintering conditions. All three glass ceramics, namely, BT110, BT111, and BT112 were found to be fully crystalline, with BT111 and BT112 comprising of biocompatible crystalline phases. The biaxial flexural strengths of the three glass ceramics ranged from 70 to 149 MPa and were shown to be superior to those of clinically established ceramics in dry conditions and following incubation in simulated physiological conditions. The bacteriostatic effect for each glass ceramic was also established, where BT112 showed an inhibitory effect against three of the most common bacteria found at implantation sites, namely, Enterococcus faecalis, methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa. The results of the evaluation suggest that the materials studied offer advantages over current clinical materials and indicate the potential suitability of the glass ceramics as therapeutic bone grafts.
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Affiliation(s)
- Mark Looney
- Medical Engineering Design and Innovation Centre, Cork Institute of Technology, Ireland
| | - Helen O' Shea
- Department of Biological Sciences, Cork Institute of Technology, Ireland
| | - Lynda Gunn
- Department of Biological Sciences, Cork Institute of Technology, Ireland
| | - Dolores Crowley
- Department of Biological Sciences, Cork Institute of Technology, Ireland
| | - Daniel Boyd
- Department of Applied Oral Sciences, Dalhousie University, Halifax, B3H 4R2, Canada
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