PV Mohanan

Publications

• 0.75

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  Pre-clinical evaluation of titanium nitride coated titanium material.

  C S Geetha, A Sabareeswaran, P V Mohanan

  Toxicology mechanisms and methods. 02/2012; 22(2):144-50.

  The titanium nitride coated titanium is a material intended for the fabrication of left ventricular assist device. As per International standards, a material is subjected to pre-clinical evaluation before fabrication of a device. Toxicity/biocompatibility studies such as acute systemic toxicity, int... [more] The titanium nitride coated titanium is a material intended for the fabrication of left ventricular assist device. As per International standards, a material is subjected to pre-clinical evaluation before fabrication of a device. Toxicity/biocompatibility studies such as acute systemic toxicity, intracutaneous irritation, in vitro haemolysis and implantation in muscle were studied as per international standards for the titanium nitride coated titanium. Acute systemic toxicity was studied in mice using physiological saline and cotton seed oil extracts of the material. Intracutaneous irritation was done by injecting the extracts of the test material and control intradermally into rabbits. Grading of erythema and oedema of test and control animals were recorded at 24, 48 and 72 h. In vitro haemolysis was carried out with material and extract of the material with rabbit blood. The muscle implantation was carried out in nine anesthetized rabbits. The implanted animals were sacrificed at the end of 1, 4 and 12 weeks, the tissue with the implanted materials were collected and subjected to histopathological analysis. The results of the study did not show any significant irritation or systemic toxicity with physiological saline and cotton seed oil extracts of the material. The percentage of hemolysis induced by the material and extract was under acceptable range. Results of the histopathological evaluation suggest that the test material did not produce any cellular changes. Hence the present study concluded that the test material is non-toxic, non-irritant, non-haemolytic and biocompatible.
• 1.72

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  Investigation of interleukin-1β release from cryopreserved blood stimulated with endotoxin.

  K B Megha, Siddharth Banerjee, P V Mohanan

  Cryobiology. 12/2011; 63(3):273-8.

  The feasibility of an indigenously developed ELISA method to determine cytokine response to wide spectrum of pyrogenic stimuli utilizing fresh human whole blood is limited by the availability of healthy donors. The possibility of using cryopreservation of pooled human blood for detection of cytokine... [more] The feasibility of an indigenously developed ELISA method to determine cytokine response to wide spectrum of pyrogenic stimuli utilizing fresh human whole blood is limited by the availability of healthy donors. The possibility of using cryopreservation of pooled human blood for detection of cytokine response to lipopolysaccharide is explored in this study. The effect of cryopreservation on blood parameters, cellular morphology and cytokine response were compared with that of the pooled fresh blood and cryopreserved blood from single and multiple donors. In vitro pyrogenic stimulation with 0.5 and 5 EU of LPS was monitored on fresh and cryopreserved pooled blood from single and multiple donors. The release of IL-1β was quantitated by Sandwich ELISA (1, 10, 25, 45 and 75 days) after storage. The results indicated that the cryopreserved blood displayed enhanced IL-1β release on stimulation with LPS, when compared to fresh blood. The maximum release of IL-1β level was observed at 2h when 5 EU of LPS was treated with pooled fresh blood which is similar to that of fresh blood. After 75 days storage of pooled cryopreserved blood the IL-1β release was maximum at 9 and 15 h when treated with 5 and 0.5 EU of LPS. Observations of the study suggest that cryopreserved pooled blood is an economically and experimentally viable alternative to fresh blood. This investigative study promises short term storage and regular supply of non-allergic, pathogen free human blood for the detection of interleukin-1β for the evaluation of in vitro pyrogenicity.
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  Assessment of oxidative stress and chromosomal aberration inducing potential of three medical grade silicone polymer materials.

  P Vijayalakshmi, C S Geetha, P V Mohanan

  Journal of biomaterials applications. 11/2011;

  Medical expenditures for devices are increasing along with the ageing of human population and the synthesis of materials such as silicone polymers is on upsurge for manufacturing these devices. The International Organization for Standardization (ISO) emphasizes a battery of tests for preclinical ass... [more] Medical expenditures for devices are increasing along with the ageing of human population and the synthesis of materials such as silicone polymers is on upsurge for manufacturing these devices. The International Organization for Standardization (ISO) emphasizes a battery of tests for preclinical assessment of biocompatibility of medical devices. Genotoxicity assays have become an integral component of these test procedures and it employs a set of in vitro and in vivo experiments to detect mutagens. Hence, this study was performed with an intention to investigate the genotoxic potential of the physiological saline extracts of three medical grade silicone polymer materials by the in vitro chromosomal aberration assay using human peripheral blood lymphocytes. Further, the oxidative stress inducing potential of the material extracts was investigated in vivo in mice liver homogenates using cyclophosphamide as positive control. The investigation revealed that none of the three materials were able to produce marked human lymphocyte chromosomal aberration, suggesting the absence of mutagens. The materials also showed negative results in their oxidative stress inducing potential, which was revealed by the normal levels of lipid peroxidation and unaltered levels of glutathione and its metabolizing enzymes in the mice liver tissue homogenates. It was interesting to observe a significant correlation between the genotoxic and antioxidant parameters investigated. Hence, it is suggested that the estimation of antioxidant status would serve as a better preliminary testing procedure prior to evaluating the genetic and molecular toxicity mechanisms of medical devices and/or materials intended for manufacture of such devices.
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  Evaluation of hydroxyapatite-bioglass and hydroxyapatite-ethyl vinyl acetate composite extracts on antioxidant defense mechanism and genotoxicity: an in vitro study.

  M Arun, P K Silja, P V Mohanan

  Toxicology mechanisms and methods. 09/2011; 21(7):561-6.

  Hydroxyapatite-bioglass (HA BG) and hydroxyapatite-ethyl vinyl acetate (HA EVA) are two composite materials that have been developed for bone substitution. Their activity on antioxidant defense mechanism and genotoxicity has not been investigated before. To further confirm its biocompatibility, the ... [more] Hydroxyapatite-bioglass (HA BG) and hydroxyapatite-ethyl vinyl acetate (HA EVA) are two composite materials that have been developed for bone substitution. Their activity on antioxidant defense mechanism and genotoxicity has not been investigated before. To further confirm its biocompatibility, the present study was undertaken to investigate the effect of HA BG and HA EVA on mice liver antioxidant mechanism along with chromosomal aberrations in human lymphocytes. Physiological saline extract of HA BG and HA EVA showed no adverse effect on liver antioxidant mechanism compared to the cyclophosphamide (CP)-induced toxicity on mice liver homogenate. The results were judged from the in vitro studies made on reduced glutathione, glutathione reductase and lipid peroxidation. These results were well supported by CP- and mytomycin C (MC)-induced genotoxicity studies on human lymphocytes in the presence and absence of a metabolic activator (S9). Hence, it was suggested that these tests could be considered for preliminary toxicological screening of materials intended for clinical applications ahead of in vivo animal model evaluation.
• 2.45

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  Detection of pyrogenicity on medical grade polymer materials using rabbit pyrogen, LAL and ELISA method.

  P V Mohanan, Siddharth Banerjee, C S Geetha

  Journal of pharmaceutical and biomedical analysis. 07/2011; 55(5):1170-4.

  The objective of the study is to detect the pyrogenicity of five medical grade gelatinous polymer materials, intended for the manufacturing of capsule for pharmaceutical applications, by an indigenously developed ELISA, LAL and rabbit pyrogen assays. The ELISA methodology includes the incubation of ... [more] The objective of the study is to detect the pyrogenicity of five medical grade gelatinous polymer materials, intended for the manufacturing of capsule for pharmaceutical applications, by an indigenously developed ELISA, LAL and rabbit pyrogen assays. The ELISA methodology includes the incubation of the sample extract with blood from a healthy donor at 37°C. Any pyrogen present in the extract induces the IL-1β which can be determined by ELISA. The rabbit pyrogen and LAL assays were performed as per standards. The result of the ELISA method indicated that all the materials extract induced high level of IL-1β as a marker for pyrogenicity. The rise in temperature of rabbit pyrogen was above 0.5°C in all materials extract. LAL assay induced an endotoxin level above 0.5EU. All the five polymer materials were found pyrogenic in all the assays. The ELISA method is very sensitive because the lowest limit of detection was 10pg/ml endotoxin. Hence it can be concluded that the ELISA method will be an added advantage for the quality control release of a batch of medical products and improving the existing methodologies in the context of reduction and replacement in the use of animal models.

• Cytogenetic Evaluation of the Physiological Saline Extract of a Newly Developed Dental Material "ORMO-48".

  P V Mohanan, Lizzy Mol

  Toxicology international. 07/2011; 18(2):155-9.

  The ORMO-48 is a new indigenous material for dental applications, developed by the Dental Products Laboratory of our Institute. The aim of the present study was to evaluate the genotoxic effect of an indigenously developed dental material in Swiss albino mice. The genotoxic effect was evaluated by m... [more] The ORMO-48 is a new indigenous material for dental applications, developed by the Dental Products Laboratory of our Institute. The aim of the present study was to evaluate the genotoxic effect of an indigenously developed dental material in Swiss albino mice. The genotoxic effect was evaluated by micronucleus and chromosomal aberration tests. Two grams of dental material was extracted in 10.0 ml of physiological saline at 70°C for 24 h. The extract was cooled to room temperature and was used for the experiment. The experimental designed had three groups each (six mice in each group) for micronucleus and chromosomal aberration tests. The first, second, and third groups were given a single exposure of physiological saline alone (control), dental material's extract (test), and cyclophosphamide (positive control) respectively for micronucleus and chromosomal aberration tests. The result of the study indicated that, the percentage of micronucleated PCE (polychromatic erythrocytes) and NCE (normochromatic erythrocytes) induced by the dental material (extract) treated group was well comparable with control group, whereas the positive control induced significantly high (P < 0.001) micronucleated PCE when compared to control. The PCE and NCE ratio of the dental material extract treated group was similar to that of control group. The chromosomal anomalies such as chromatid/chromosomal breaks, centric rings, exchanges, dicentric, and acentric fragments were evaluated. The result showed that the anomalies of the dental material extract treated group were similar to control group, however, significant anomalies were observed in the cyclophosphamide treated group. Hence, the present study concluded that the indigenously developed biocompatible dental material, ORMO-48 is non genotoxic at our laboratory conditions.
• 2.35

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  Inflammatory response to pyrogens determined by a novel ELISA method using human whole blood.

  Siddharth Banerjee, P V Mohanan

  Journal of immunological methods. 06/2011; 369(1-2):146-53.

  Presence of pyrogens on implants, medical devices, drugs and biological materials compromise on the biosafety and poses a major health hazard in therapeutics. Detection of pyrogenic contamination has so far been done with either in vivo rabbit pyrogen assay or Limulus Amoebocyte Lysate (LAL) methods... [more] Presence of pyrogens on implants, medical devices, drugs and biological materials compromise on the biosafety and poses a major health hazard in therapeutics. Detection of pyrogenic contamination has so far been done with either in vivo rabbit pyrogen assay or Limulus Amoebocyte Lysate (LAL) methods, each of which having their distinct advantages and disadvantages. An indigenously developed ELISA method quantifying the pro-inflammatory response triggered by pyrogens on human whole blood is demonstrated for its versatility to detect the pyrogenic response to gram-negative, gram-positive bacteria, chemical and biological pyrogens. The method was used to test and quantitate the pyrogen levels in polymeric biomaterials. Unlike the existing pyrogen test procedures, this assay is adapted to detect all pyrogens, besides yielding faster, sensitive and quantifiable data, thereby reduce/replace animal experimentation. The method also provided insight into the possible correlation between variable blood profile among individuals and their role in determining inflammatory response to different pyrogenic stimuli.
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  The reversal of diabetes in rat model using mouse insulin producing cells - a combination approach of tissue engineering and macroencapsulation.

  Sudhakar Muthyala, V R Rana Raj, Mira Mohanty, P V Mohanan, Prabha D Nair

  Acta biomaterialia. 02/2011; 7(5):2153-62.

  Type 1 diabetes is a chronic disorder resulting from the autoimmune destruction of insulin-producing cells, a leading cause of morbidity and mortality all over the world. In this study a tissue engineering approach was compared with a macroencapsulation approach to reverse type 1 diabetes in a rat m... [more] Type 1 diabetes is a chronic disorder resulting from the autoimmune destruction of insulin-producing cells, a leading cause of morbidity and mortality all over the world. In this study a tissue engineering approach was compared with a macroencapsulation approach to reverse type 1 diabetes in a rat model, using mouse pancreatic progenitor cell (PPC)-derived islet-like clusters and mouse islets. For the tissue engineering approach the cells were cultured on gelatin scaffolds cross-linked with EDC in the presence of polyvinylpyrrolidone in vitro (GPE scaffolds), while for the macroencapsulation approach the cells were encapsulated in polyurethane-polyvinylpyrrolidone semi-interpenetrating networks. In the combination approach the cells cultured on GPE scaffolds were further encapsulated in a polyurethane-polyvinylpyrrolidone capsule. Real time PCR studies and the glucose challenge assay have shown that cells on GPE scaffolds could express and secrete insulin and glucagon in vitro. However, under in vivo conditions the animals treated by the tissue engineering approach died within 15-20 days and showed no reversal of their diabetes, due to infiltration of immune cells such as CD4 and CD8 cells and macrophages. In the macroencapsulation approach the animals showed euglycemia within 25 days, which was maintained for further 20 days, but after that the animals died. Interestingly, in the combination approach the animals showed reversal of hyperglycemia, and remained euglycemic for up to 3 months. The time needed to achieve initial euglycemia was different with different cell types, i.e. the combination approach with mouse islets achieved euglycemia within 15 days, whereas with PPC-derived islet-like clusters euglycemia was achieved within 25 days. This study confirmed that a combination of tissue engineering and macroencapsulation with mouse islets could reverse diabetes and maintain euglycemia in an experimental diabetes rat model for 90 days.
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  Advantages of hyaluronic acid as a component of fibrin sheet for care of acute wound.

  T V Anilkumar, Jaseer Muhamed, Anumol Jose, Arun Jyothi, P V Mohanan, Lissy K Krishnan

  Biologicals : journal of the International Association of Biological Standardization. 02/2011; 39(2):81-8.

  Skin injury is followed by accumulation of a fibrin based provisional matrix which normally drives the process of wound repair. Exogenous fibrin with extra cellular matrix (ECM) components can also favor the wound healing process. In a preliminary study we found that lyophilized fibrin sheet (FS) ar... [more] Skin injury is followed by accumulation of a fibrin based provisional matrix which normally drives the process of wound repair. Exogenous fibrin with extra cellular matrix (ECM) components can also favor the wound healing process. In a preliminary study we found that lyophilized fibrin sheet (FS) arrest bleeding from rabbit skin wound but it remained dry during the repair period and did not accelerate the healing process better than untreated control. In the current study, hyaluronic acid (HA) was incorporated into FS and the resultant HA-FS promoted water retention and improved wound healing process. Gross-morphology, histopathology and histomorphometry were employed to compare qualitative and quantitative difference of wound healing in treated group against controls. In experimental sites (HA-FS), re-epithelialization was completed by 14 days with neo-vascularization and deposition of wavy bundles of collagen in the treated sites. Rate of healing process was different in treated and untreated wounds and most striking difference was the appearance of appendages, sebaceous gland and hair follicle at some locations in HA-FS treated sites. Therefore, HA with fibrin can create an effective wound care matrix which promotes water retention and wound healing potential.
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  Toxicity and hemostatic potential of poly [ß-(1, 4)-2-amino-2-deoxy-D-glucosamine] based hemostatic material on albino rabbits.

  P V Mohanan, Leo Mavely, Ashish Pandya

  Toxicology mechanisms and methods. 11/2010; 21(1):25-30.

  The present study was designed to evaluate the hemostatic potential of poly [ß-(1, 4)-2-amino-2-deoxy-D-glucosamine]-based hemostatic dressing material on albino rabbits. In vitro cytotoxicity study of poly [ß-(1, 4)-2-amino-2-deoxy-D-glucosamine]-based hemostatic dressing samples was carried out wi... [more] The present study was designed to evaluate the hemostatic potential of poly [ß-(1, 4)-2-amino-2-deoxy-D-glucosamine]-based hemostatic dressing material on albino rabbits. In vitro cytotoxicity study of poly [ß-(1, 4)-2-amino-2-deoxy-D-glucosamine]-based hemostatic dressing samples was carried out with L929 cells, and the cytotoxic potential was evaluated at the end of 24 h. The skin irritation was carried out in albino rabbits. Extract of the material was applied topically and irritation response was evaluated up to 72 h. The hemostatic study was initiated in rabbits after general anesthesia with a mixture of ketamine and xylazine. Using a sharp surgical blade, a 1.0 cm longitudinal incision was made on the right (test) and left (control) marginal ear arteries. Through the resultant jet spray of blood, the right 1.0 cm long wound was immediately covered with a 2 × 2 cm(2) piece of test material (poly [ß-(1,4)-2-amino-2-deoxy-D glucosamine] of known weight (w1). Similarly the left wound (1.0 cm length) was covered with commercially-available bandage (control) of known weight (w2). Direct pressure was applied for 2 min and then the samples were removed and weighed immediately (w3 for test and w4 for control) after hemostasis. Blood loss (w3-w1 for the Test and w4-w2 for control) was calculated from the materials weight before and after absorbing blood. The result of the study indicated that the indigenously developed material has local biological activity in the form of hemostatic action and, together with its ability to activate macrophages, resulted in wound healing applications. Hence, the present study concluded that the poly [ß-(1,4)-2-amino-2-deoxy-D glucosamine]-based hemostatic dressing material is non-toxic, non-skin irritant, and has better hemostatic potential than a commercially available material with enhanced hemostatic capabilities for various wound dressing.
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  Role of immune cells and inflammatory cytokines in regulation of fibrosis around silicone expander implants.

  Josna Joseph, Mira Mohanty, P V Mohanan

  Journal of materials science. Materials in medicine. 02/2010; 21(5):1665-76.

  This study aimed to investigate the progress of wound healing around silicone expander with particular emphasis on fibroblasts, myofibroblasts and collagen in the repair phase. Semi-quantitative evaluation of inflammatory cells and their cytokines, fibroblasts and myofibroblasts at the tissue-materi... [more] This study aimed to investigate the progress of wound healing around silicone expander with particular emphasis on fibroblasts, myofibroblasts and collagen in the repair phase. Semi-quantitative evaluation of inflammatory cells and their cytokines, fibroblasts and myofibroblasts at the tissue-material interface was carried out. Commercially available silicone expander was implanted in gluteus muscle of young female Wistar rats for 3, 7, 14, 30, 90 and 180 days. Ultra high molecular weight polyethylene served as control. The cellular response was studied by immunohistochemistry and Transmission Electron Microscopy. A thick collagenous fibrous capsule was observed around the silicone expander at 180 days, with persistent myofibroblasts, lymphocytes and macrophages as compared to the thin fibrous encapsulation around the UHMWPE implants. The regulatory role of cytokines and immune cells in myofibroblast persistence in tissue-implant interface around silicone expander has been extensively studied. Results of this study indicate the need to elucidate the signaling molecules in the transition of fibroblast to myofibroblast around silicone expander implants.
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  Investigative study of myofibroblasts and cytokines in peri-implant tissue of silicone breast expander by rt-PCR in a rat model.

  Josna Joseph, Mira Mohanty, P V Mohanan

  Journal of biomaterials science. Polymer edition. 01/2010; 21(10):1389-402.

  The excessive collagen deposition around silicone breast implants followed by contracture and development of severe pain is a major clinical problem. This study was conducted to investigate the profibrotic and antifibrotic cytokines secreted by inflammatory cells and development of myofibroblasts at... [more] The excessive collagen deposition around silicone breast implants followed by contracture and development of severe pain is a major clinical problem. This study was conducted to investigate the profibrotic and antifibrotic cytokines secreted by inflammatory cells and development of myofibroblasts at the tissue material interface around silicone breast expander and ultra-high-molecular-weight polyethylene (UHMWPE). Both materials were implanted in rats for 30, 90 and 180 days. Inflammatory cells and collagen deposition at the material-tissue interface were assessed with Haematoxylin-Eosin and Masson's Trichrome stain. Gene expression of TGFbeta, IL-1beta, IFNgamma, IL10 and alpha-SMA was quantitated by real-time (RT)-PCR in the peri-implant tissue. Results indicate a difference in collagen deposition and myofibroblast development around both materials with involvement of TGFbeta, IFNgamma and IL10. The results emphasise the need for further investigation into the molecular mechanisms of protomyofibroblast and myofibroblast formation around silicone implants, which would provide information on these target cells for inhibitory therapy in the clinical situation.
• 4.64

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  SURFACE PHOSPHORYLATED COPOLYMER PROMOTES DIRECT BONE BONDING.

  Sailaja Sivkamiammal Gopalakrishnanchettiar, Mira Mohanty, Kumary T V, Mohanan P V, Ramesh P, Harikrishna Varma

  Tissue engineering. Part A. 04/2009;

  Abstract The bone bonding potential of surface phosphorylated poly (2-hydroxyethyl methacrylate-co-methyl methacrylate), poly (HEMA-co-MMA) has been investigated and compared with commercially available poly (methyl methacrylate) PMMA bone cement (CMW1 radiopaque, Depuy, Johnson & Johnson, UK) a... [more] Abstract The bone bonding potential of surface phosphorylated poly (2-hydroxyethyl methacrylate-co-methyl methacrylate), poly (HEMA-co-MMA) has been investigated and compared with commercially available poly (methyl methacrylate) PMMA bone cement (CMW1 radiopaque, Depuy, Johnson & Johnson, UK) as control. Poly(HEMA-co-MMA) is synthesized by free radical initiated copolymerization and surface functionalized by phosphorylation. The X-ray photoelectron spectroscopy confirms the presence of surface bound phosphate groups on poly (HEMA-co-MMA). The surface phosphorylated poly(HEMA-co-MMA) promotes in vitro biomineralization, cell viability, cell adhesion, and expression of bone specific markers such as osteocalcin and alkaline phosphatase. The bone implantation study performed in rabbits as per ISO 10993-6; 1994 (E), shows that surface phosphorylated poly (HEMA-co-MMA) elicits bone bonding and new bone formation. New woven bone trabeculae are formed at the defect site of surface phosphorylated poly (HEMA-co-MMA) within one week, while for control sample, inflammatory cells predominantly macrophages, fibroblasts and fibrocytes are present at the cortical margins around the defect. The four and twelve weeks post implantation results show that, the major part of the defects around the surface phosphorylated poly (HEMA-co-MMA) implant is bridged with new woven bone, with significant remodeling (evident from resorption bays) along both the margins of the defect. But, for control implants, the defects are only partially closed, with slight remodeling along the margins, but most of them are separated by fibrous tissue.
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  In vivo response of novel calcium phosphate-mullite composites: Results up to 12 weeks of implantation.

  Shekhar Nath, Bikramjit Basu, Mira Mohanty, P V Mohanan

  Journal of biomedical materials research. Part B, Applied biomaterials. 02/2009;

  In this paper, the in vivo response, in particular, the histocompatibility of newly developed CaP-mullite composites is reported. In the present experiments, the bioceramic implants were inserted in the long bones of healthy rabbits according to standard protocols (ISO-10993) and the tissue response... [more] In this paper, the in vivo response, in particular, the histocompatibility of newly developed CaP-mullite composites is reported. In the present experiments, the bioceramic implants were inserted in the long bones of healthy rabbits according to standard protocols (ISO-10993) and the tissue response was studied at different time intervals of up to 12 weeks. Ultra high-molecular weight polyethylene (UHMWPE) was used as control samples. The postimplant bone-material interfaces were analyzed by staining of histological sections, following bone tissue histopathology protocols. The interface zones were critically observed by fluorescent optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Importantly, no inflammation, necrosis was observed during this tenure. New bone formation was observed at all the implantation time intervals (1-12 weeks). However, the bone integrity with the material was increased after 12 weeks of implantation. Although macrophages and fibrous tissue were present during the first week of implantation, they were not observed on histology sections after 12 weeks postimplantation. More importantly, foci of chondrocytes could be observed after 12 weeks of implantation. Remodeling of Haversian canal was observed at the interfacial area of natural bone and implant material. All the observations were assessed critically to analyze the in vivo biocompatibility of this novel composite material. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009.
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  Amphotericin B-gum arabic conjugates: synthesis, toxicity, bioavailability, and activities against Leishmania and fungi.

  K K Nishi, M Antony, P V Mohanan, T V Anilkumar, P M Loiseau, A Jayakrishnan

  Pharmaceutical research. 06/2007; 24(5):971-80.

  PURPOSE: Gum arabic, a branched polysaccharide consisting of more than 90% arabinogalactan having a molecular weight around 250,000 Da is the oldest and best known of all natural gums. The objective of the present investigation was to examine whether amphotericin B (AmB), the polyene antibiotic when... [more] PURPOSE: Gum arabic, a branched polysaccharide consisting of more than 90% arabinogalactan having a molecular weight around 250,000 Da is the oldest and best known of all natural gums. The objective of the present investigation was to examine whether amphotericin B (AmB), the polyene antibiotic when conjugated to periodate oxidized gum arabic still retained its anti-fungal and anti-leishmanial activity and to evaluate its toxicity and bioavailability. METHODS: AmB conjugated to the oxidized polysaccharide through Schiff's linkages in the unreduced (imine) and reduced (amine) forms were characterized for the drug content, hemolytic potential, molecular mass, in vitro release and were examined for anti-fungal activity against Candida albicans and Cryptococcus neoformans and for anti-leishmanial activity against promastigotes of Leishmania donovani in culture. Toxicity and bioavailability were evaluated by intravenous (i.v) injections of the conjugates in mice and rabbits respectively. RESULTS: The conjugates were found to be non-hemolytic and mice withstood a dosage of 20 mg (AmB)/kg body weight of both conjugates. Histological examination of the internal organs of mice showed no lesions in kidney, brain, heart or liver. Estimation of the residual drug in the internal organs 7 days post injection showed that the spleen still retained 8.4 +/- 0.53 microg/g of tissue. AmB was found to be released from both conjugates in vitro although the release from the imine conjugate was much faster than from the amine conjugate. The concentrations inhibiting parasite growth by 50% (IC(50)) values for the imine conjugate against promastigotes of L. donovani LV9 and DD8 strains were 0.37 +/- 0.04 and 1.44 +/- 0.18 microM respectively. The IC(50) values for the amine conjugates were much higher. The minimum inhibitory concentration (MIC) against C. albicans and C. neoformans was in the range of 0.5-0.9 microg/mL for both imino and amino conjugates. The bioavailability of the conjugate in rabbits showed that the imine conjugate maintained a plasma concentration in the range of 20 to 5 microg/mL while for the amine conjugate it was in the range of 17 to 3 microg/mL over 24 h. CONCLUSIONS: The drug conjugates were stable, non-hemolytic and non-toxic to the internal organs of the animal and showed good anti-fungal and anti-leishmanial activity in vitro. In spite of the large molecular weight of the polysaccharide, AmB from the conjugates showed bioavailability after i.v injection. Since the highest concentration of AmB was found in the spleen after a single injection, these conjugates may have potential in anti-leishmanial therapy.
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  Biological evaluation of pliable hydroxyapatite-ethylene vinyl acetate co-polymer composites intended for cranioplasty.

  Shiny Velayudhan, T V Anilkumar, T V Kumary, P V Mohanan, A. C. Fernandez, H K Varma, P Ramesh

  Acta biomaterialia. 04/2005; 1(2):201-9.

  Hydroxyapatite (HAP) is undoubtedly a material suitable for repairing the defective bone tissue. However, the brittleness and non-malleability of HAP limit its clinical application as a cranioplastic analogue. To improve these properties, pliable, osteoconductive composites composed of HAP and ethyl... [more] Hydroxyapatite (HAP) is undoubtedly a material suitable for repairing the defective bone tissue. However, the brittleness and non-malleability of HAP limit its clinical application as a cranioplastic analogue. To improve these properties, pliable, osteoconductive composites composed of HAP and ethylene vinyl acetate co-polymer (EVA) have been developed. This study reports the biocompatibility evaluation of the newly developed composite material. Composites of two compositions, containing 40 and 50 volume percentage of HAP, were evaluated. In vitro cell culture cytotoxity studies were carried out using L929 cell line. Intracutaneous irritation studies, and intramuscular implantation studies were carried out on rabbits. Cell culture studies showed that the composite was non-cytotoxic to mouse fibroblast cell line. Intracutaneous irritation studies did not show any gross signs of tissue reaction. Histological analysis after six months of implantation in the paravertebral muscles of rabbit showed that all the implants under study were covered with a thin soft tissue capsule. On the basis of these observations, we conclude that the composite materials are biocompatible and hence are a candidate material for implantation in the cranium.
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  Long term tissue response to titanium coated with diamond like carbon.

  M Mohanty, T V Anilkumar, P V Mohanan, C V Muraleedharan, G S Bhuvaneshwar, F Derangere, Y Sampeur, R Suryanarayanan

  Biomolecular engineering. 09/2002; 19(2-6):125-8.

  Diamond like carbon (DLC) coatings were deposited on to Ti substrates by plasma enhanced chemical vapor deposition technique. Ti and DLC/Ti samples were implanted in skeletal muscle of rabbits. The samples were explanted after 1, 3, 6 and 12 months and the tissue-cell interaction was studied. Our da... [more] Diamond like carbon (DLC) coatings were deposited on to Ti substrates by plasma enhanced chemical vapor deposition technique. Ti and DLC/Ti samples were implanted in skeletal muscle of rabbits. The samples were explanted after 1, 3, 6 and 12 months and the tissue-cell interaction was studied. Our data indicate both DLC/Ti and bare Ti to be compatible with skeletal muscle.
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  Regression of solid tumour using laser and 5-aminolevulinic acid in mice.

  P V Mohanan, R S Jayasree, A K Gupta

  Journal of biomaterials applications. 05/2002; 16(4):267-74.

  Solid tumour reducing effect in Swiss albino mice induced with Dalton's Lymphoma Ascites tumour cells (DLA) and Ehrlich Ascites tumour cells (EA) was determined with the application of He-Ne and Nd:YAG lasers along with the photosensitising agent 5-Aminolevulinic acid (ALA). The experiment was d... [more] Solid tumour reducing effect in Swiss albino mice induced with Dalton's Lymphoma Ascites tumour cells (DLA) and Ehrlich Ascites tumour cells (EA) was determined with the application of He-Ne and Nd:YAG lasers along with the photosensitising agent 5-Aminolevulinic acid (ALA). The experiment was designed with six groups and each group consisted of six animals. Animals in Groups I-III were injected with DLA cell lines and Groups IV-VI were injected with EA cell lines (1 x 10(6) in 0.1ml saline) subcutaneously in the right hind limb of mice to induce solid tumours. The tumour was further treated with photosensitiser induced laser therapy. The hyperthermic effect of Nd:YAG laser on tumour reduction was also evaluated. The results of the study suggest that the combination of He-Ne laser and 1 W Nd:YAG laser along with the photosensitiser 5-Aminolevulinic acid is a very effective therapeutic method for the treatment of tumour of DLA and EA cell lines. It is clear from the results that this mode of therapy very well depends on the type of tumour that has to be treated.
• 3.48

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  Preventive effect of melatonin against brain mitochondria DNA damage, lipid peroxidation and seizures induced by kainic acid.

  P V Mohanan, Hiro-aki Yamamoto

  Toxicology letters. 04/2002; 129(1-2):99-105.

  The effects of kainic acid on mitochondria DNA (mtDNA) or lipid peroxidation in mice brain and, preventive effects of melatonin against its effects were investigated in vivo. Broad-spectrum limbic and severe sustained seizures were observed in all mice when kainic acid (45 mg/kg) was injected intrap... [more] The effects of kainic acid on mitochondria DNA (mtDNA) or lipid peroxidation in mice brain and, preventive effects of melatonin against its effects were investigated in vivo. Broad-spectrum limbic and severe sustained seizures were observed in all mice when kainic acid (45 mg/kg) was injected intraperitoneally (ip) to eight mice. These seizures were completely abolished by the simultaneous administration of melatonin (20 mg/kg, ip), a potent scavenger of hydroxyl radical. However, slight limbic seizures or severe sustained seizures were observed when melatonin was injected in animals 30 min before or 15 min after the kainic acid administration. The administration of kainic acid caused damage to mtDNA in brain frontal and middle cortex. These effects were abolished when melatonin was injected in animals 0 or 30 min before, but not 15 min after the kainic acid administration. In vitro or in vivo exposure of kainic acid elicited an increase in lipid peroxidation in a concentration- or dose-dependent manner. The increased lipid peroxidation induced by kainic acid was attenuated by co-treatment with melatonin. These results indicate that there may be a positive relationship among seizures, brain mtDNA damages and increased lipid peroxidation. Hence, our present results suggest that the hydroxyl radicals produced by kainic acid cause damage on mtDNA and the increase of lipid peroxidation in brain, leading to severe seizures. These effects were completely prevented by co-treatment with melatonin, a potent scavenger of hydroxyl radicals.
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  Effects of melatonin on paraquat or ultraviolet light exposure-induced DNA damage.

  H A Yamamoto, P V Mohanan

  Journal of pineal research. 12/2001; 31(4):308-13.

  The effect of paraquat or ultraviolet (UV) light exposure on calf thymus DNA was investigated in vitro. When paraquat (0.1, 0.25, 0.5, or 1.0 mM) was incubated with brain or lung homogenates prepared from mice in the presence of calf thymus DNA at 37 degrees C for 90 min, paraquat inflicted damage t... [more] The effect of paraquat or ultraviolet (UV) light exposure on calf thymus DNA was investigated in vitro. When paraquat (0.1, 0.25, 0.5, or 1.0 mM) was incubated with brain or lung homogenates prepared from mice in the presence of calf thymus DNA at 37 degrees C for 90 min, paraquat inflicted damage to DNA in a concentration-dependent manner. However, DNA damage was completely abolished by co-treatment with melatonin (1.5 mM), a hydroxyl radical (.OH) scavenger. In addition, when paraquat (1.0 or 2.5 mM) was incubated with liver microsomes in the presence of calf thymus DNA and Fe3+ (3.0 microM) at 37 degrees C for 90 min, DNA damage also occurred and was prevented by the co-treatment of melatonin (1.5 mM). DNA was also damaged by UV light exposure or when the Fenton reaction was induced; the Fenton reaction generates .OH; again, the damage was blocked by the co-treatment of melatonin. These results suggest that .OH induced by paraquat or UV light probably account for the DNA damage. In short, DNA damage induced by paraquat and UV radiation were completely prevented by co-treatment with the .OH scavenger, melatonin.