Browsing by Author "Joseph, R"

Now showing 1 - 20 of 21
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    A comparative evaluation of coefficient of friction and mechanical properties of commercially available foley catheters
    (JOURNAL OF BIOMATERIALS APPLICATIONS, 2001)
    Three commercially available urinary catheters were evaluated for their coefficient of friction and mechanical properties, which are two important parameters as far as the intended use is considered. The apparent coefficient of friction was measured from the slope of the force versus normal load graph using an in-house fabricated setup. The mechanical properties like ultimate tensile strength, elongation at break and modulus were evaluated before and after aging in synthetic urine. The swelling behavior of the catheter samples was studied in toluene and found to correlate well with the mechanical properties.
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    Assessment of in vivo chromosomal aberrations - Potency of zinc mercapto benzo thiazole
    (JOURNAL OF BIOMATERIALS APPLICATIONS, 2000)
    Chromosomal aberrations are microscopically visible changes in the chromosome structure. The double-stranded breaks are the ultimate DNA lesions for chromosomal aberrations. The purpose of the present study was to evaluate the induction of chromosomal aberrations by the rubber accelerator zinc mercapto benzo thiazole (ZMBT). The experiment was designed with five groups, each composed of four Swiss albino mice. The first three groups received ZMBT at 1920, 960, and 483 mu g/20 g animal. The remaining two groups were the vehicle (cotton seed oil) and positive (methyl methane sulphonate) controls. Animals were given a single dose of test; and control samples by IP injection. Colchicine (20 mu g/animal) was administered 90 minutes before sacrificing the animals. All the animals were sacrificed at the end of 36 h by cervical dislocation. Bone marrow preparations were made, stained with Giemsa stain, and examined for chromosomal abnormalities. The results indicated a lack of incidence of chromosomal abnormalities in the test and control groups. However, significant chromosomal abnormalities such as gaps, breaks, and translocations were observed in the positive control group. Hence, the study concluded that ZMBT at different concentrations fails to induce structural chromosomal aberrations in bone marrow cells.
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    Characterization of surface modified polyester fabric
    (JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE, 2009) Joseph, R; Shelma, R; Rajeev, A; Muraleedharan, CV
    Woven polyethylene terephthalate (PET) fabric has been used in the construction of vascular grafts and sewing ring of prosthetic heart valves. In an effort to improve haemocompatibility and tissue response to PET fabric, a fluoropolymer, polyvinylidine fluoride (PVDF), was coated on PET fabric by dip coating technique. The coating was found to be uniform and no significant changes occurred on physical properties such as water permeability and burst strength. Cell culture cytotoxicity studies showed that coated PET was non-cytotoxic to L929 fibroblast cell lines. In vitro studies revealed that coating improved haemocompatibility of PET fabric material. Coating reduced platelet consumption of PET fabric by 50%. Upon surface modification leukocyte consumption of PET was reduced by 24%. About 60% reduction in partial thromboplastin time (PTT) observed when PET was coated with PVDF. Results of endothelial cell proliferation studies showed that surface coating did not have any substantial impact on cell proliferation. Overall results indicate that coating has potential to improve haemocompatibility of PET fabric without affecting its mechanical performance.
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    Effect of amine activators on the properties of chemical cured dental composites
    (JOURNAL OF BIOMATERIALS APPLICATIONS, 1997)
    The purpose of this study was to evaluate the reactivity and the effect of concentration of three tertiary amines upon the mechanical properties of a chemical curing dental composite. Chemical cured composite pastes were prepared by keeping peroxide concentration constant at 1 wt% (by weight of resin mixture) and by varying the amine/peroxide molar ratio from 0.25 to 1.5. Composite samples were prepared for all three amine pastes aged for 1, 15, 30, 45, and 60 d stored at 8, 22, and 37 degrees C. The loss in activity of the tertiary amine with time was measured. Changes in compressive strength, diametral tensile strength, and microhardness were also measured. A sharp decrease in working and setting times corresponding to increased activity was noticed with an increased amine content. The activity was found to vary in the order N,N-dimethyl p-toluidine (DMPT) > 2-(4-dimethylaminophenyl) ethanol (DMAPEA) > N,Ndiethanol p-toluidine (DEFT). DMPT is found to be more temperature sensitive than DMAPEA and DEFT. However, DEFT is found to provide better storage stability out of all three amines tested. Each amine was found to possess optimum concentrations at which the mechanical properties showed maximum values. DEFT is preferred for long-term storage stability in chemical-cured dental composites where aging tends to reduce the activity of the amine.
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    Effect of morphological features and surface area of hydroxyapatite on the fatigue behavior of hydroxyapatite-polyethylene composites
    (BIOMACROMOLECULES, 2005) Joseph, R; Tanner, KE
    The effect of surface area and morphological features of filler particles on the fatigue behavior of hydroxyapatite-filled high-density polyethylene composites was studied. Composites containing 40 vol % filler were injection-molded into tensile bars, gamma-irradiated, and subjected to sinusoidal tensile fatigue at a frequency of 2 Hz. To simulate the physiological environment, the tests were conducted at 37 degrees C in saline. Results showed that properties such as secant modulus, cyclic energy dissipation, dynamic creep strain, hysteresis loops, and even fracture surfaces differ depending on the morphology and surface area of the fillers used.
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    Effect of photografting 2-hydroxyethyl acrylate on the hemocompatibility of electrospun poly(ethylene-co-vinyl alcohol) fibroporous mats
    (MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS, 2016) Mayuri, PV; Bhatt, A; Joseph, R; Ramesh, P
    Poly(ethylene-co-vinyl alcohol) (EVAL) has been recommended as a material suitable for blood contacting applications. Effect of ethylene content and associated hydrophobicity of EVAL on the blood-material interactions have been documented in the literature. In this work, surface chemistry of EVAL substrate was altered by photografting a hydrophilic monomer, 2-hydroxyethyl acrylate (HEA) with the aid of a photoinitiator, benzophenone (BP), and the effect of surface modification on the blood-material interactions was investigated. Since the modified material was intended to be used as leukodepletion filters, a solution containing EVAL, HEA and BP was electrospun into fibroporous mats and UV treated to induce grafting. Degree of grafting, bonding between fibers and fiber diameter increased with increase in UV exposure time whereas mechanical properties showed a decreasing trend. Decreased water contact angle indicated improved wetting characteristics. In vitro hemocompatibility tests revealed that the modified EVAL surface exhibited significantly lower hemolytic activity, protein adsorption and platelet adhesion than neat EVAL. The modification did not have any substantial effect on the activation of the complement system and coagulation parameters. Photografting led to significant reduction in the adhesion of red blood cells (RBC) whereas white blood cell (WBC) consumption remained above 90%. The results implied that photografting HEA on EVAL substantially improves hemocompatibility of EVAL and when it is used as a filter, it selectively removes leukocytes and allows easy passage of other blood components. (C) 2015 Elsevier B.V. All rights reserved.
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    Effect of photografting 2-hydroxyethylacrylate on the hemocompatibility of electrospun poly(ethylene-co-vinyl alcohol) fibroporous mats
    (Materials Science and Engineering, 2015-11) Mayuri, PV; Bhatt, A; Joseph, R; Ramesh, P
    Poly(ethylene-co-vinyl alcohol) (EVAL) has been recommended as a material suitable for blood contacting applications. Effect of ethylene content and associated hydrophobicity of EVAL on the blood–material interactions have been documented in the literature. In this work, surface chemistry of EVAL substrate was altered by photografting a hydrophilic monomer, 2-hydroxyethyl acrylate (HEA) with the aid of a photoinitiator, benzophenone (BP), and the effect of surface modification on the blood–material interactions was investigated. Since the modified material was intended to be used as leukodepletion filters, a solution containing EVAL, HEA and BP was electrospun into fibroporous mats and UV treated to induce grafting. Degree of grafting, bonding between fibers and fiber diameter increased with increase in UV exposure time whereas mechanical properties showed a decreasing trend. Decreased water contact angle indicated improved wetting characteristics. In vitro hemocompatibility tests revealed that the modified EVAL surface exhibited significantly lower hemolytic activity, protein adsorption and platelet adhesion than neat EVAL. The modification did not have any substantial effect on the activation of the complement system and coagulation parameters. Photografting led to significant reduction in the adhesion of red blood cells (RBC) whereas white blood cell (WBC) consumption remained above 90%. The results implied that photografting HEA on EVAL substantially improves hemocompatibility of EVAL and when it is used as a filter, it selectively removes leukocytes and allows easy passage of other blood components
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    Inherently X-ray opaque polyurethane microspheres for biomedical applications
    (INTERNATIONAL JOURNAL OF POLYMERIC MATERIALS AND POLYMERIC BIOMATERIALS, 2017) Kiran, S; Sunny, MC; Joseph, R
    In this work synthesis and characterization of inherently X-ray opaque, nonresorbable polyurethane microspheres with well-calibrated particles in a defined range of sizes suitable for embolization is reported. In order to impart X-ray opacity to the polyurethane, a bifunctional monomer, namely, 4,4-isopropylidenediphenol (BPA) was iodinated and this iodinated compound was used as one of the monomers during polyurethane synthesis. The resultant X-ray opaque polyurethane was converted into microspheres using an oil-in-water emulsion and solvent evaporation technique. Microspheres obtained had diameters in the range of 200-500 mu m, were noncytotoxic and free from X-ray attenuating additives. In vivo X-ray fluoroscopic imaging carried out in a rabbit cadaver model showed that these microspheres were sufficiently X-ray opaque to be visualized under fluoroscopic conditions. [GRAPHICS] .
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    Injectable selfcrosslinking hydrogels for meniscal repair: A study with oxidized alginate and gelatin
    (Carbohydrate Polymers, 2020-05) Resmi, R; Parvathy, J; John A, A; Joseph, R
    Injectable in situ gelling hydrogels are viable treatment options for meniscal injuries occurring in athletes. The present study aims to develop an injectable hydrogel via borax complexation of oxidized alginate, followed by a self-crosslinking reaction with gelatin through a Schiff’s base reaction. Gelation kinetics and degree of crosslinking could be controlled by changing the concentration of components and the formation of Schiff ;'s base formation was confirmed by Raman spectroscopy. The injectable alginate dialdehyde-gelatin (15ADA20G) hydrogel showed 423 ± 20 % water uptake, had an average pore size of 48 μm and compressive strength 295 ± 32 kPa. Phase contrast images, scanning electron micrographs and actin staining depicted adhesion, profuse proliferation, and distribution of fibrochondrocytes on the hydrogel demonstrating its cytocompatibility. Application of hydrogel at the pig meniscal tear ex vivo showed good integration with the host meniscal tissue. Further, the histology of 15ADA20G hydrogel filled meniscus showed retention of hydrogel in the close proximity of meniscal tear even after 3days in culture. The self-crosslinking injectable hydrogel offers a niche for the growth of fibrochondrocytes.
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    Interfacial stick-slip transition in hydroxyapatite filled high density polyethylene composite
    (BULLETIN OF MATERIALS SCIENCE, 2006) Joseph, R; Martyn, MT; Tanner, KE; Coates, PD
    Effect of filler addition and temperature on the stick-slip transition in high density polyethylene melt was studied. Results showed that shear stresses corresponding to stick-slip transition increases with the addition of filler. Increase in temperature also increases the shear stresses for stick-slip transition. The features of the flow curves of composites and that of unfilled system remain identical. Filler addition lowers the shear rate at which the transition occurs. The composite extrudate did not show characteristic extrudate distortions associated with the unfilled polymer.
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    Phenotypic Modulation of Cell Types around Implanted Polyethylene Terephthalate Fabric in Rabbit Muscle
    (TOXICOLOGIC PATHOLOGY, 2013) Muhamed, J; Revi, D; Joseph, R; Anilkumar, T
    Whereas the nature of healing reaction in skeletal muscle following implantation of biomaterial has been extensively studied, the extent of variation in cell phenotypes is poorly known. Here, we studied the phenotypic alteration of cell types following injury in skeletal muscle of rabbits implanted with a commonly used biomaterial, polyethylene terephthalate (PET) fabric. Following implantation, histomorphological features were studied after 1, 4, and 12 weeks. Routine objective histomorphological evaluation was supplemented with histochemistry for collagen and immunohistochemistry for proliferating cell nuclear antigen (PCNA), CD34, vimentin, and alpha smooth muscle actin (alpha-SMA). The extent of reaction was quantified. The foreign body giant cells were found to comprise subpopulations, based on the variation in vimentin detectability or the presence of differentially capable proliferating nuclei (PCNA positive). Many rhabdomyocytes adjacent to the implant were PCNA-positive and some of them showed CD34 positivity. Often, the rhabdomyocytes very near to implanted PET fabric assumed a myofibroblast phenotype as evidenced by vimentin and/or alpha-SMA positivity at immunohistochemistry. Overall, the results suggested a phenotypic alteration of native cell types following implantation of PET fabric in rabbit skeletal muscle. Quantification of such cell types at the tissue-material interphase in relation to the deposition of collagen may be desirable during safety evaluation of biomaterials by histomorphology.
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    Polyurethane thermoplastic elastomers with inherent radiopacity for biomedical applications
    (JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A, 2012) Kiran, S; James, NR; Jayakrishnan, A; Joseph, R
    Synthesis and characterization of three different radiopaque thermoplastic polyurethane elastomers are reported. Radiopacity was introduced to the polyurethanes by incorporating an iodinated chain extender, namely, 4,4'-isopropylidinedi-(2,6-diiodophenol) (IBPA), into the polymer chain during polyurethane synthesis. Radiopaque polyurethanes (RPUs) were synthesized by reacting 4,4'-methylenebis(phenyl isocyanate) (MDI), IBPA, and three different diols. The polyols used for the synthesis were polypropylene glycol, polycaprolactone diol, and poly(hexamethylene carbonate) diol. RPUs were characterized by infrared spectroscopy, contact angle measurements, thermogravimetry, dynamic mechanical analysis, energy dispersive X-ray analysis, gel permeation chromatography, X-ray fluorescence spectroscopy, and X-radiography. X-ray images showed that all RPUs prepared using IBPA as the chain extender are highly radiopaque compared with an Aluminum wedge of equivalent thickness. Elemental analysis revealed that the polyurethanes contained 1819% iodine in the polymer matrix. The RPUs developed have radiopacity equivalent to that of a polymer filled with 20 wt % barium sulfate. Results revealed that RPUs of wide range of properties may be produced by incorporating different diols as the soft chain segment. Cell culture cytotoxicity studies conducted using L929 cells by direct contact test and MTT assay proved that these RPUs are noncytotoxic in nature. (c) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.
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    Preclinical evaluation of hydrogel sealed fluropassivated indigenous vascular prosthesis
    (Indian Journal of Medical Research, 2018-03) Unnikrishnan, M; Umashankar, PR; Viswanathan, S; Savlania, A; Joseph, R; Muraleedharan, CV; Agrawal, V; Shenoy, SJ; Krishnan, LK; Mohanan, PV; Sabareeswaran, A
    Background & objectives: Polyethylene terephthalate (PET) graft, designed and developed at our institute for vascular reconstruction, is porous to promote optimal incorporation and neointima formation, requiring pre-clotting or biomodification by sealing the pores before implantation. The objective of this study was to characterize, test and perform preclinical evaluation of hydrogel (alginate dialdehyde cross-linked gelatin) sealed fluoropassivated PET vascular prosthesis in pig model, so as to avoid pre-clotting, for its safety and efficacy before employing the indigenous and less expensive graft for clinical use. Methods: Hydrogel sealed, fluoropassivated PET vascular prosthesis were tested for haemocompatibility and toxicity followed by small animal toxicology tests and in vivo experiments in pigs receiving implantation at thoracic aorta. All 33 animals received test as well as control grafts with a plan for phased explantation at 2, 12 and 26 weeks. All animals underwent completion angiogram at the end of procedure as well as before graft explantation. Results: Haemocompatibility tests for haemolysis and toxicity tests showed no adverse events in tested mice and rabbits. Completion angiogram showed intact anastamosis and patent graft in each animal in post-operative period and at explantation. Gross and histopathological examination showed wellencapsulated grafts, clean glistening neointima and no evidence of thrombus in both test and control grafts. Interpretation & conclusions: Hydrogel sealed, fluoropassivated PET vascular prosthesis was found non-toxic, haemocompatible and remained patent in in vivo studies at planned intervals.
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    Release of dithiocarbamates into artificial sweat from latex vulcanizates: Effects of the accelerator type and storage time
    (JOURNAL OF APPLIED POLYMER SCIENCE, 2006) Abraham, EK; Ramesh, P; Joseph, R
    The release of commonly used dithiocarbamate accelerators, namely, zinc diethyldithiocarbamate (ZDEC), zinc dibutyldithiocarbamate (ZDBC), zinc dibenzyldithiocarbamate, zinc isobutyldithiocarbamate, and zinc diisononyldithiocarbamate, into artificial sweat from natural rubber latex vulcanizates was studied. The extent of release of ZDEC was much higher than that of ZDBC or other higher homologues, as indicated by high-performance liquid chromatography analysis. The effect of the storage time on the extent of release of ZDEC into artificial sweat from vulcanizates prepared with various amounts of ZDEC was studied. The result showed that ZDEC migrated significantly to the surface of the vulcanizates upon storage, and the amount that migrated increased with an increase in the shelf time. Moreover, the amount of ZDEC that migrated increased with an increase in the amount of ZDEC added to the latex formulations. The rate of migration, as determined from the slopes of the migration curves, was dependent on the residual ZDEC content, which in turn depended on the initial level of ZDEC incorporated during latex compounding. The analysis of the migration data showed that the migration followed a Fickian behavior, and the diffusion coefficient of ZDEC was slightly dependent on the concentration. (c) 2006 Wiley Periodicals, Inc.
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    Release of dithiocarbamates into sweat from natural rubber latex surgical gloves
    (RUBBER CHEMISTRY AND TECHNOLOGY, 2005) Abraham, EK; Ramesh, P; Joseph, R; Mohanan, PV; Remakumari, VM
    The release of zinc dialkyldithiocarbamates from a batch of surgical gloves into the sweat of human subjects was studied. Healthy volunteers from both sexes were asked to don the gloves on both hands for I It. The identification and estimation of dithiocarbamate residues released into the sweat were carried out using thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). The thin layer chromatogram showed that zinc diethyldithiocarbamate (ZDEC) accelerator residues were released into the sweat of volunteers. The estimation by high performance liquid chromatography revealed that the amount of ZDEC released varied among the human subjects despite using the same brand of glove. The effect of sweat rate and pH on the amount of ZDEC released into hand sweat was investigated. The results indicated that it may not be possible to derive a relationship between the sweat-extractable ZDEC and sweat rate or pH of hand sweat. The dithiocarbamate release was studied in the laboratory using a physiologically simulated medium, namely, artificial sweat at different pH levels. The glove was filled with artificial sweat and extracted for I hat 37 degrees C. It was found that amount of artificial sweat-extractable ZDEC varied with changes in pH of artificial sweat. Lack of a clear relationship between the sweat-extractable ZDEC and sweat rate or pH of hand sweat indicated that factors such as hand exercise, glove-fit, etc., may also be considered when simulating actual use conditions in vitro.
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    Scaffold for liver tissue engineering: Exploring the potential of fibrin incorporated alginate dialdehyde-gelatin hydrogel.
    (International J of Biological Macromolecules, 2020-11) Resmi, R; Anusree, KS; Joseph, R; Bhatt, A
    Introduction Development of a tissue-engineered construct for hepatic regeneration remains a challenging task due to the lack of an optimum environment that support the growth of hepatocytes. Hydrogel systems possess many similarities with tissues and have the potential to provide the microenvironment essential for the cells to grow, proliferate, and remain functionally active. Methods In this work, fibrin (FIB) incorporated injectable alginate dialdehyde (ADA) - gelatin (G) hydrogel was explored as a matrix for liver tissue engineering. ADA was prepared by periodate oxidation of sodium alginate. An injectable formulation of ADA-G-FIB hydrogel was prepared and characterized by FTIR spectroscopy, Scanning Electron Microscopy, and Micro-Computed Tomography. HepG2 cells were cultured on the hydrogel system; cellular growth and functions were analyzed using various functional markers. Results FTIR spectra of ADA-G-FIB depicted the formation of Schiff's base at 1608.53 cm−1 with a gelation time of 3 min. ADA-G-FIB depicted a 3D surface topography with a pore size in the range of 100–200 μm. The non-cytotoxic nature of the scaffold was demonstrated using L929 cells and more than 80 % cell viability was observed. Functional analysis of cultured HepG2 cells demonstrated ICG uptake, albumin synthesis, CYP-P450 expression, and ammonia clearance. Conclusion ADA-G-FIB hydrogel can be used as an effective 3D scaffold system for liver tissue engineering.
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    Synthesis and characterization of a noncytotoxic, X-ray opaque polyurethane containing iodinated hydroquinone bis(2-hydroxyethyl) ether as chain extender for biomedical applications
    (JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A, 2014) Kiran, S; Joseph, R
    An iodinated urethane polymer that does not require addition of X-ray attenuating additives to impart Xray opacity was synthesized and characterized for biomedical applications. A new X-ray opaque diiodo compound, namely, 2,2'-(2,5-diiodobenzene-1,4-diyl)bis(oxy)diethanol (DBD), was synthesized by iodinating hydroquinone bis(2-hydroxyethyl) ether and this compound was used as chain extender during polyurethane synthesis so that X-ray opacity could be imparted to the polymer formed. X-ray opaque polyurethane (XPU) was synthesized by reacting 1,6-diisocyanatohexane with poly(hexamethylene carbonate) diol and DBD. X-ray opacity of XPU was measured with a fluoroscopy machine using BaSO4-filled polyurethane as controls. Radiographic images showed that XPU sample had X-ray opacity equivalent to 15 wt % BaSO4-filled polymer. In vivo imaging in a rabbit model showed that the material could be readily distinguishable from bones. XPU was found to be hemocompatible and noncytotoxic to L929 fibroblast cell lines. Optical transparency measurements using ultraviolet-visible spectrophotometer showed that XPU transmitted 85% of visible light. (C) 2013 Wiley Periodicals, Inc.
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    Synthesis and characterization of X-ray opaque polycarbonate urethane: Effect of a dihalogenated chain extender on radiopacity and hemocompatibility
    (Journal of Biomedical Materials Research Part A., 2014-10) Kiran, S; Joseph, R
    An inherently radiopaque poly(carbonate urethane) containing fluorine and iodine atoms in the polymer chain was synthesized and characterized. Radiopaque polyurethane was synthesized from 1,6-diisocyanatohexane (HDI), poly (hexamethylene carbonate)diol (PHCD) and a newly synthesized chain extender having fluorine and iodine in the molecule, namely, 4,4'-(1,1,1,3,3,3-hexafluoropropane-2,2-diyl)bis(2,6-diiodophenol) (IBAF). IBAF monomer imparted radiopacity and improved the hemocompatibility of the resultant polymer. For comparative evaluation, polyurethanes (PU) were synthesized by reacting monomers HDI and PHCD without any chain extender and also by reacting HDI and PHCD along with noniodinated, but fluorine containing, version of the above chain extender, namely, 4,4'-(Hexafluoroisopropylidene) diphenol (BAF). Chain extended PUs showed improved mechanical and thermal properties, and hemocompatibility compared to the nonchain extended PU. Radiopacity measurements by fluoroscopy showed that IBAF incorporated PU of 200 µm thickness had radiopacity equivalent to that of 25% barium sulfate filled noniodinated PU of same thickness and to that of 0.6-mm thick aluminum wedge. In vivo imaging using a rabbit cadaver model showed clearly distinguishable image of IBAF incorporated PU sample. All the PU materials were noncytotoxic to L929 mouse fibroblast cells. Preliminary results obtained from blood-material interaction studies showed that incorporation of fluorinated chain extenders in the PUs resulted in significant reduction in the adhesion of white blood cells onto the PU material surface and also resulted in prolonged partial thromboplastin time. Results suggest that incorporation of fluorine and iodine containing chain extenders would lead to the development PU with improved hemocompatibility and radiopacity
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    Synthesis of calcium-containing methacrylate resin
    (JOURNAL OF APPLIED POLYMER SCIENCE, 2001) Abraham, EK; Francis, A; Ramesh, P; Joseph, R
    The calcium salt of p-aminobenzoic acid [p-ABA(Ca)] was reacted with epichlorohydrin to yield the multifunctional epoxy resin. The epoxy resin was characterized by IR spectroscopy, epoxy equivalent, calcium estimation, high performance liquid chromatography (HPLC) and refractive index. The epoxy resin was further reacted with methacrylic acid to yield the calcium containing methacrylate resin, which was characterized by IR, hydroxyl value, iodine value, HPLC and refractive index. (C) 2001 John Wiley & Sons, Inc.
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    Tensile set behavior of Foley catheter balloons
    (JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, 1999)
    The removal of indwelling urinary balloon catheters from patients is usually associated with many problems. The problems such as balloon deflation failure; encrustations on balloons, eyes, and lumen; and catheter associated infections are widely discussed in the literature. The tensile set exhibited by the catheter balloon material could also play a role and further complicate the removal process. This article addresses this issue by comparing the tensile set behavior of the balloon material from three commercially available Foley catheters, The balloon materials were subjected to aging in synthetic urine at 37 degrees C for 28 days to simulate clinical conditions. The deflation time of catheter balloons aged in similar conditions were also measured. It was found that different brands of catheters exhibited statistically significant differences in their properties. The tensile set data of the aged samples could be correlated with the deflation time of the balloons. The clinical significance of the tensile set is also highlighted. (C) 1999 John Wiley & Sons; Inc.