Browsing by Author "Antony, M"

Now showing 1 - 7 of 7
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    Amphotericin B-gum arabic conjugates: Synthesis, toxicity, bioavailability, and activities against Leishmania and fungi
    (PHARMACEUTICAL RESEARCH, 2007)
    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 mu g/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% (IC50) values for the imine conjugate against promastigotes of L. donovani LV9 and DD8 strains were 0.37 +/- 0.04 and 1.44 +/- 0.18 mu M respectively. The IC50 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 mu g/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 mu g/mL while for the amine conjugate it was in the range of 17 to 3 mu g/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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    Costing of homograft valve-Based on the experience from a homograft valve bank programme at a tertiary referral hospital in India
    (J Academy Hospital Administration., 2013-04) Jawahar, SK; Beena, B; Jayakumar, K; Antony, M
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    Functionalized carbon dots enable simultaneous bone crack detection and drug deposition
    (J. Mater. Chem B., 2015-01) Shanthikrishna; Radhakumary, C; Antony, M; Sreenivasan, K
    Recently, carbon dots (CDs) have become one of the most sought nanomaterials for biological applications owing to their excellent fluorescence, chemical inertness and biocompatibility. This article depicts the generation of a fluorescent nano probe using CDs for viewing bone cracks and simultaneous drug delivery to the cracked or infected sites. Water soluble polyethylene glycol diamine capped CDs were conjugated with glutamic acid (GA), a calcium targeting ligand, and ciprofloxacin as an antibacterial model drug. Physicochemical characterizations, cytotoxicity evaluation, haemolysis and antibacterial activity studies of the synthesized probe and its ability to target onto bone are demonstrated. Our results indicate that there is significant scope in developing functionalized CDs as theranostic agents.
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    Infective endocarditis due to Streptococci and Enterococci: A 3year retrospective study
    (Indian Journal of Pathology and Microbiology, 2018-12) Raja, K; Antony, M; Harikrishnan, S
    Introduction: Infective endocarditis (IE) is an infection of the heart valves with an aggregation of bacteria in a fibrin plaque called vegetation. Aims and Objectives: This is a retrospective study of all infective endocarditis cases due to alpha haemolytic streptococci and enterococci. Methods: All cases of infective endocarditis cases due to alpha haemolytic streptococci and enterococci in a period of three years from 1st January 2010 to 31st December 2012 were included. Isolation of the same organism from more than one set of blood cultures was taken as a confirmed case of infective endocarditis. Clinical and serological parameters were recorded using a proforma. Results: Native valve endocarditis was more common with only five prosthetic valves being involved. Out of 89 clinically suspected cases of IE in the three years from Jan 2010 to Dec 2012, for which blood was sent for culture, 63(70.78%) samples were positive by culture. Of these, 42/63(66.66%) were due to alpha-lytic Streptococci, enterococci and rare gram positive cocci. The rare ones included Enterococcus gallinarum, abiotropha defective, Vagococcus fluvialis and Nutritionally Variant Streptococci(NVS). High level Aminoglycoside resistance(HLAR) was also encountered. The varied and important features of these isolates are discussed. Complications and treatment are described. Conclusion: From a clinical microbiology point of view, the major challenge faced by the microbiologist in diagnosis of IE is proper aseptic collection of sample before starting antibiotics with a need for multiple samples to detect and also to prove the causative organism. Sensitivity reporting can be a difficult task in the context of NVS, HLAR and gram positives that are slow growing. Congestive failure and embolisation occurs even when the antibiotic treatment is successful.When patients go in for complications, it is very rarely due to wrong antibiotics.
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    Role of phenotypic testing in determining the mechanism of resistance in Gram-negative bacilli & risk factors for meropenem resistance
    (Indian Journal of Medical Research, 2019-02) Raja, K; Antony, M; Rani, R; Bridget, G
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    Selective estimation of C-reactive protein in serum using polymeric formulations without antibody
    (SENSORS AND ACTUATORS B-CHEMICAL, 2010) Raj, V; Hari, PR; Antony, M; Sreenivasan, K
    A new method without employing antibody for the estimation of C-reactive protein (CRP) in serum is presented. The method centres on the variation of fluorescence intensity of pair copolymers, containing a fluorophore (Fluoreseinamine isomer 1) and O-Phosphorylethanolamine (PEA), a ligand of CRP. We found that the fluorescence of fluorophore attached copolymer was quenched in the presence of copolymer conjugated with PEA. The fluorescence emission was, however, increased when CRP was added into the solution of the copolymers. The intensity of fluorescence increased linearly up to a concentration of 250 ng/mL of CRP and then attained a constant value which remains the same with additional quantity of CRP. This observation was assigned to the saturation of the binding sites. Other proteins namely, albumin, fibrinogen and globulin did not show any interference in the measurement. The method was used for the estimation of CRP in blood serum of patients reported to the cardiology and the data compared well with the quantity of CRP in the same samples estimated using immunoassay method. Our results suggest that the polymer pick up CRP selectively from a complex milieu like serum. The method is simple, cost effective and sensitive with a detection limit of 20 ng/mL. (C) 2010 Elsevier B.V. All rights reserved.
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    Synthesis and evaluation of a hydrogel that binds glucose and releases ciprofloxacin
    (JOURNAL OF MATERIALS SCIENCE, 2010) Manju, S; Antony, M; Sreenivasan, K
    This study reports the formation of a hydrogel generated by polymerizing aminophenyl boronic acid in polyvinyl alcohol (PVA). The gel formed as a result of complexation between the -OH groups of PVA, and boronic acid moieties were stable and exhibited high degree of swelling proportional to the concentration of glucose. Extended swelling was attributed to the strong affinity of the gel to glucose and to the subsequent breaking of the bond formed between PVA and boronic acid groups. Interestingly, the gel was found to bind a high amount of glucose. We evaluated the hydrogel in terms of its ability to bind glucose and to release ciprofloxacin. Retention of antibacterial efficacy of the released drug was also demonstrated. Features such as swelling, drug release, and glucose binding reflect the possibility of tuning a new dressing for wounds particularly in diabetic patients.