J. Santerre - Academia.edu (original) (raw)

Papers by J. Santerre

Canadian Journal of Plant Science, 1960

Forty-seven chemicals, including antibiotics, detergents, quaternary ammonium salts, mercury comp... more Forty-seven chemicals, including antibiotics, detergents, quaternary ammonium salts, mercury compounds, disinfectants and protectants, were tested for their effectiveness as potato seed piece disinfectants after inoculating each potato set with bacterial ring rot. None of the substances tested was as effective as a solution of acidified mercuric chloride (2:1000 + 1 per cent HCl) in a 10-minute dip treatment which gave 93 to 98 per cent control. A more effective control of the disease (100 per cent) was obtained when seed stock contained only 1 per cent diseased tubers.

Polymers, 2017

The monomeric components of resin composites in dental restorative materials are susceptible to h... more The monomeric components of resin composites in dental restorative materials are susceptible to hydrolysis in the oral cavity. The main objective of this study was to assess the bio-stability of fluorinated urethane dimethacrylates and determine the nature of fluoro-chemistry interactions with protein and bacterial adhesion (both sources of hydrolytic activity) onto cured resin. Degradation studies were performed in the presence of either albumin (in a mildly alkaline pH) or cholesterol esterase (CE). The surface chemistry of the polymers was assessed by water contact angle measurements, pre-and post-incubation with albumin. Adhesion of Streptococcus mutans to cured resin was investigated. The fluorinated monomers were more stable against degradation when compared to the commercial monomer bisphenol A-diglycidyl methacrylate (BisGMA). While fluorinated monomers showed hydrolytic stability with respect to CE, all fluorinated monomers underwent some degree of degradation with albumin. The fluoro-chemistry did not reduce protein and/or bacterial adhesion onto the surface, however post incubation with albumin, the fluorinated surfaces still presented hydrophobic character as determined by the high contact angle values ranging from 79 • to 86 •. These monomers could potentially be used to increase the hydrophobicity of polymeric composites and provide a means to moderate esterolytic degradation associated with the monomeric component of the polymers within the oral cavity.

Colloids and Surfaces, 1985

ABSTRACT

Acta Biomaterialia, 2015

Monocyte interactions with implanted biomaterials can contribute significantly to the ability of ... more Monocyte interactions with implanted biomaterials can contribute significantly to the ability of a biomaterial to support tissue integration and wound healing, as opposed to a chronic pro-inflammatory foreign body reaction, provided the materials are designed to do so. However, there are few biomaterials available designed to regulate immune cell response with the intention of reducing the pro-inflammatory activation state. Material chemistry is a powerful tool for regulating protein and cell interactions that can be incorporated into surfaces while maintaining desired mechanical properties. The aspects of material chemistry that can support monocyte activation away from a pro-inflammatory state are still poorly understood. Protein adsorption is a key initial event that transforms the surface of a biomedical device into a biological substrate that will govern subsequent cellular interactions. In this study, the chemistry of degradable block polyurethanes, termed degradable polar hydrophobic ionic (D-PHI) polyurethanes, were studied for their unique interactions with bound immunoglobulin G (IgG), a pro-inflammatory protein that supports monocyte-biomaterial interactions. The specific immunological active sites of the polyurethane-adsorbed protein were compared with IgG's adsorbed state on a homopolymeric material with surface chemistry conducive to cell interactions, e.g. tissue culture polystyrene (TCPS). IgG-coated TCPS supported sustained monocyte adhesion and enhanced monocyte spreading, effects not observed with IgG-coated PU. The degradable PU was subsequently shown to reduce the number of exposed IgG-Fab sites following pre-adsorption vs. IgG adsorbed to TCPS, with antibody inhibition experiments demonstrating that Fab-site exposure appears to dominate monocyte-biomaterial interactions. Minor changes in chemical segments within the PU molecular chains were subsequently investigated for their influence on directing IgG interactions towards reducing pro-inflammatory activity. A reduction in chemical heterogeneity within the PU, without significant differences in other material properties known to regulate monocyte response, was shown to increase Fab exposure and subsequently led to monocyte interactions similar to those observed for IgG-coated TCPS. These results infer that reduced IgG-Fab site exposure can be directed by material chemistry to attenuate pro-inflammatory monocyte interactions with biomaterial surfaces, and identify the chemical features of polymeric biomaterial design responsible for this process. Statement of Significance There is currently limited understanding of material design features that can regulate protein-material interactions in order to prevent adverse inflammatory responses to implanted biomaterials. In this paper, monocyte interactions with biomaterials (specifically a block co-polymeric degradable polyurethane [D-PHI] and tissue culture polystyrene [TCPS]) were investigated as a function of their interactions with adsorbed immunoglobulin G (IgG). D-PHI was shown to attenuate IgG-induced monocyte retention and spreading by reducing IgG-Fab site exposure upon adsorption relative to TCPS. Aspects of D-PHI chemistry important in regulating Fab site exposure were determined. This study thus identifies features of biomaterials, using D-PHI as a case study, which can contribute to the development of new immunomodulatory biomaterial design.

Dental materials : official publication of the Academy of Dental Materials, 2014

The ester linkages contained within dental resin monomers (such as Bisphenol A-glycidylmethacryla... more The ester linkages contained within dental resin monomers (such as Bisphenol A-glycidylmethacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA)) are susceptible to hydrolytic degradation by salivary esterases, however very little is known about the specific esterase activities implicated in this process. The objective of this work was to isolate and identify the dominant proteins from saliva that are associated with the esterase activities shown to be involved in the degradation of BisGMA. Human whole saliva was collected and processed prior to separation in a HiPrep 16/60 Sephacryl S-200 HR column. The fraction with the highest esterase activity was further separated by an anion exchange column (Mono-Q (10/100G)). Isolated fractions were then separated by gel electrophoresis, and compared to a common bench marker esterase, cholesterol esterase (CE), and commercial albumin which has been reported to express esterase activity. Proteins suspected of containing esterase act...

Canadian journal of surgery. Journal canadien de chirurgie, 2000

Aseptic loosening after total joint replacement remains the most common reason for long-term impl... more Aseptic loosening after total joint replacement remains the most common reason for long-term implant failure. Macrophages activated by submicron wear particles of the polyethylene liner used in joint replacement have been shown to be the source of periprosthetic bone loss. Understanding the role of material chemistry in macrophage activation and the subsequent effects that macrophage-derived enzymes play in the degradation of implanted biomaterials is key to developing methods for prolonging the lifespan of implantable materials.

Journal of Biomaterials Science, Polymer Edition, 2014

This study investigated the interaction of human circulating angiogenic cells (CACs) with a degra... more This study investigated the interaction of human circulating angiogenic cells (CACs) with a degradable polar hydrophobic ionic polyurethane (D-PHI) which has been previously shown to exhibit anti-inflammatory character and favorable interactions with human endothelial cells (ECs). Given the implication of the CACs in microvessel development it was of intrinsic interest to expand our knowledge of D-PHI biocompatibility with this relevant primary cell involved in angiogenesis. The findings will be compared to a well-established benchmark substrate for CACs, fibronectin-coated tissue culture polystyrene (TCPS). Immunoblotting analysis showed that CACs were a heterogeneous population of cells composed mostly of monocytic cells expressing the CD14 marker. Assessment of the cytokine release profile, using ELISA, showed that D-PHI supported a higher concentration of interleukin-10 (IL-10) when compared to the concentration of tumor necrosis factor alpha, which is indicative of an anti-inflammatory phenotype, and was different from the response with TCPS. It was found that the CACs were attached to D-PHI and remained viable and functional (nitric oxide production) during the seven days of culture. However, there did not appear to be any significant proliferation on D-PHI, contrary to the CAC growth on fibronectin-coated TCPS. It was concluded that D-PHI displayed some of the qualities suitable to enable the retention of CACs onto this substrate, as well as maintaining an anti-inflammatory phenotype, characteristics which have been reported to be important for angiogenesis in vivo.

Journal of Materials Science - J MATER SCI, 2001

Photo-initiated polymerizations of two series of di(meth)acrylate oligomers, one bisphenol-A base... more Photo-initiated polymerizations of two series of di(meth)acrylate oligomers, one bisphenol-A based and the other ethylene glycol based, with a camphorquinone/tertiary amine radical photo-initiator system were studied using differential scanning calorimetry. Bisphenol-A based oligomers polymerized much faster than ethylene glycol based oligomers because the higher viscosity of E-bis-A oligomers induced an autoacceleration upon exposure to ultraviolet (UV) radiation; however, higher vinyl conversions were observed with ethylene glycol oligomers due to their greater segmental mobility and elastomeric character of the cured networks. The two series also showed very different temperature dependence for vinyl group conversion. The polymerization rate of E-bis-A DMA oligomers increased when the number of oxyethyl units increased from four to six, but the rate decreased when the spacer length further increased. The exponential factors of the rate dependence on the CQ concentration for all t...

Macromolecules, 1983

Binding isotherms of dodecyltrimethylammonium (DTA+) ions with dextran sulfate (DxS) and poly(sty... more Binding isotherms of dodecyltrimethylammonium (DTA+) ions with dextran sulfate (DxS) and poly(styrenesulfonate) (PSS) were determined in the presence of multivalent counterions, Mg2+, Ca2+, Zn2+, and La3+, by utilizing a potentiometric technique based on a DTA+ selective solid-state membrane electrode. The results indicate a highly cooperative nature of the binding process, similar to what has been reported earlier in the presence of NaC1. All divalent counterions give practically identical binding isotherms for PSS-DTA+, but in the case of DxS, Cap+ interferes more with DTA+ binding than do Mg2+ and Zn2+. The presence of La3+ at a very low concentration causes a lower binding affinity for DTA+ of both DxS and PSS.

Journal of Endodontics, 2000

To prevent reinfection after root canal treatment, root filling materials should be antimicrobial... more To prevent reinfection after root canal treatment, root filling materials should be antimicrobial. This study assessed the antimicrobial efficacy of KT-308, a modified glass ionomer cement sealer, and three formulations of ZUT, a combination of KT-308 and three different concentrations of a silvercontaining zeolite. Discs prepared from the test materials and paper controls were incubated in Brain Heart Infusion broth for 12 wk. At 2-wk intervals, 18 discs from each group were inoculated with Enterococcus faecalis and incubated for periods of l to 30 h. After further processing, a 200 pl aliquot of the broth immersing each disc was plated on agar and assessed for bacterial growth. The remaining broth was measured for optical density. All ZUT discs demonstrated no bacterial growth after 15 h of interaction, in contrast to abundant growth with the KT-308 and paper discs. Thus ZUT effectively suppressed adherent E. faecabs after 15 h, irrespective of its concentration and age.

Critical Reviews in Oral Biology & Medicine, 2001

This article reviews the principal modes of dental composite material degradation and relates the... more This article reviews the principal modes of dental composite material degradation and relates them to the specific components of the composites themselves. Particular emphasis is placed on the selection of the monomer resins, the filler content, and the degree of monomer conversion after the clinical materials are cured. Loss of mechanical function and leaching of components from the composites are briefly described, while a more detailed description is provided of studies that have considered the chemical breakdown of materials by agents that are present in the oral cavity, or model the latter. Specific attention will be given to the hydrolysis process of monomer and composite components, i.e., the scission of condensation-type bonds (esters, ethers, amides, etc.) that make up the monomer resins, following reaction of the resins with water and salivary enzymes. A synopsis of enzyme types and their sources is outlined, along with a description of the work that supports their ability...

Journal of Dental Research, 2010

Bis-GMA-containing resin composites and adhesives undergo biodegradation by human-saliva-derived ... more Bis-GMA-containing resin composites and adhesives undergo biodegradation by human-saliva-derived esterases, yielding Bis-hydroxy-propoxy-phenyl-propane (Bis-HPPP). The hypothesis of this study is that the exposure of dental restorations to saliva-like esterase activities accelerates marginal bacterial microleakage. Resin composites (Scotchbond, Z250, 3M) bonded to human dentin were incubated in either buffer or dual-esterase media (pseudocholinesterase/cholesterol-esterase; PCE+CE), with activity levels simulating those of human saliva, for up to 90 days. Incubation solutions were analyzed for Bis-HPPP by high-performance liquid chromatography. Post-incubation, specimens were suspended in a chemostat-based biofilm fermentor cultivating Streptococcus mutans NG8, a primary species associated with dental caries, for 7 days. Bacterial microleakage was assessed by confocal laser scanning microscopy. Bis-HPPP production and depth and spatial volume of bacterial cell penetration within the...

Journal of Dental Research, 2004

Pseudocholinesterase (PCE) and cholesterol esterase (CE) can hydrolyze bisphenylglycidyl dimethac... more Pseudocholinesterase (PCE) and cholesterol esterase (CE) can hydrolyze bisphenylglycidyl dimethacrylate (bisGMA) and triethylene glycol dimethacrylate (TEGDMA) monomers. This study will test the hypothesis that enzyme activities showing CE and PCE character are found in human saliva at levels sufficient to hydrolyze ester-containing composites important to restorative denstistry. The study also seeks to ask if the active sites of CE and PCE with respect to composite could be inhibited. Photo-polymerized model composite resin was incubated in PCE and CE solutions, in the presence and absence of a specific esterase inhibitor, phenylmethylsulfonyl fluoride (PMSF). Incubation solutions were analyzed for resin degradation products by high-performance liquid chromatography (HPLC), UV spectroscopy, and mass spectrometry. Saliva was found to contain both hydrolase activities at levels that could degrade composite resins. PMSF inhibited the composite degradation, indicating a material hydrol...

Journal of Cellular Physiology, 2004

Monocytes are recruited to the material surface of an implanted biomedical device recognizing it ... more Monocytes are recruited to the material surface of an implanted biomedical device recognizing it as a foreign body. Differentiation into macrophages subsequently occurs followed by fusion to form foreign body giant cells (FBGCs). Consequently, implants can become degraded, cause chronic inflammation or become isolated by fibrous encapsulation. In this study, a relationship between material surface chemistry and the FBGC response was demonstrated by seeding mature monocyte‐derived macrophages (MDMs) on polycarbonate‐based polyurethanes that differed in their chemical structures (synthesized with poly(1,6‐hexyl 1,2‐ethyl carbonate) diol, and either 14C‐hexane diisocyanate and butanediol (BD) (referred to as HDI) or 4,4′‐methylene bisphenyl diisocyanate and 14C‐BD (referred to as MDI)) and material degradation assessed. At 48 h of cell‐material interaction, the FBGC attached to HDI were more multinucleated (73%) compared to MDI or the polystyrene (PS) control (21 and 36%, respectively)...

Journal of Cellular Physiology, 2000

During the acute inflammatory response to implanted medical devices, human neutrophils (PMN) rele... more During the acute inflammatory response to implanted medical devices, human neutrophils (PMN) release oxidative and hydrolytic activities which may ultimately contribute to the degradation of the biomaterial. In this study, the biological activities secreted by live PMNs which may contribute to biodegradation were investigated using a 14C label in the monomer unit of a poly(ester-urea-urethane) (PEUU) substrate. By using specific inhibitors, it was possible to propose a mechanism for PMN-mediated biodegradation. PMN, labeled with 3H-arachidonic acid, released significantly more 3H when adherent to PEUU than when adherent to tissue culture grade polystyrene (P<0.05). The phospholipase A2 (PLA2) inhibitors, aristolochic acid (ARIST) and quinacrine (QUIN), decreased the release of 3H and inhibited PEUU biodegradation (>50%, P<0.05). ARIST had no effect on cell viability, whereas QUIN significantly decreased it. The serine protease inhibitor, phenylmethylsulfonylfluoride inhibited biodegradation, but did not decrease cell survival. There is evidence to suggest that activation via the PLA2 pathway caused the release of hydrolytic activities which were able to elicit 14C release from PEUU. The role of oxidative compounds which were released via activation by phorbol myristate acetate (PMA), was not apparent, since PMA inhibited biodegradation and cell survival (>40%, P<0.05). This study has shown that it is possible to find out the differences in PMN activation through the PLA2 pathway when exposed to different material surfaces, making this a model system worthy of further investigation.

Journal of Biomedical Materials Research, 2002

Macrophages are the major cell type observed in the inflammatory membrane retrieved at implant re... more Macrophages are the major cell type observed in the inflammatory membrane retrieved at implant revision surgery. In this study, mature human monocyte‐derived macrophages (MDM) were adapted to a previously established in vitro model to examine the influence of high‐density polyethylene (HDPE) particulate (4–10 μm) on MDM viability. HDPE particles were suspended in soluble type I collagen, which subsequently was solidified on glass coverslips. Mature human macrophages, derived from differentiating peripheral blood monocytes on polystyrene for 10 days, were incubated in culture media on collagen controls and collagen–particle substrata for 31 days. Histologic analysis demonstrated that MDMs were in contact with the particles at 2 h. The majority of the particles were associated with the cells within 24 h. Based on electron microscopy, those cells associated with the particles appeared to be morphologically activated rather than necrotic or apoptotic. Assessment of cell viability reveal...