Browsing by Author "Mathai, J"

Now showing 1 - 9 of 9
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    Biochemical lesions of platelets stored as concentrates in PVC bags
    (INDIAN JOURNAL OF MEDICAL RESEARCH, 1997)
    Acid-base status of platelet suspension during storage is a measure of the gas permeability of the bag material. To assess the efficacy of the bags available in our market to store platelets, we compared biochemical lesions of platelets stored in an Indian polyvinyl chloride (PVC) triple bag against a Japanese PVC bag standardized for 5 days platelet storage. Platelet concentrates prepared in both control and test PVC bags were stored for 72 h. Two ml samples were drawn 1 h after preparation, and then at 24 h intervals, for analysis. Our data show that the mean pH value in the test bags was maintained above 6.5. However, the CO2 tension was high and O-2 tension was low. We also analyzed malondialdehyde (MDA) formation which is a measure of arachidonic acid metabolism, and seemed to be unaffected in stored platelets. Lactate dehydrogenase (LDH) was not released into the plasma excessively anti hence significant platelet lysis was absent during storage. Hypotonic shock response (HSR) of platelets stored in both test and control bags was comparable, indicating the possibility of satisfactory post-transfusion recovery.
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    Effect of temperature on functional response of platelet concentrates stored in PVC bags
    (INDIAN JOURNAL OF MEDICAL RESEARCH, 1997)
    Haemostatic efficacy of platelet concentrates prepared and stored in locally available PVC triple bags was compared against a Japanese bag. In vitro functional parameters studied included shape change, aggregation and secretion in response to ADP. We have observed remarkable difference in the aggregatory response of platelets stored at slightly varying temperatures. The stimulatory responses of platelets stored with constant agitation at 70 strokes per min and 23+/-2 degrees C, deteriorated drastically by the time platelets were stored for 48 h. Both the rate and the extent of aggregation were affected showing no response to ADP at 72 h. However, when platelets were stored in a BOD incubator, thermostated at 22+/-0.5 degrees C, with continuous horizontal agitation at 70 strokes per min, 50 per cent functional response was retained till 72 h. We also demonstrated fragmentation of platelet membrane during storage. The membrane fragments collected bq. high speed centrifugation, expressed PF3 activity. Shedding of microvesicles indicates alterations at the membrane level that possibly cause functional lesion during storage. Our data suggest the significance of controlling the storage temperature steadily, to get maximum post transfusion efficacy.
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    Glutaraldehyde cross-linking of lectins to marker enzymes: Protection of binding site by specific sugars
    (INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS, 2000)
    The role of bound specific sugars in protecting the sugar binding activity of several galactose binding proteins during their covalent conjugation to horse radish peroxidase by glutaraldehyde-mediated cross-linking was examined by: a) affinity matrix binding of the conjugate, b) enzyme linked lectin assay and c) hemagglutination assay. During conjugation using 1% glutaraldehyde, protection of jack fruit (Artocarpus integrifolia) lectin (jacalin) activity depended on concentration of specific sugar present during conjugation; optimum protection was offered by 50 mM galactose. This indicated the presence of one or more primary groups at the binding site of jacalin, which is (are) essential for sugar binding. On the other hand, such essential amino group(s) was not indicated at the sugar binding site of the peanut lectin, bovine heart galectin or of the human serum anti alpha-galactoside antibody, since exclusion of sugar during their conjugation to HRP did not diminish sugar binding activity. The differential behavior is discussed in the light of reported differences in sugar specificities. Results indicated that sugar mediated blocking of active site may be used in characterization of the latter in lectins.
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    Haemolysin test for characterization of immune ABO antibodies
    (INDIAN JOURNAL OF MEDICAL RESEARCH, 2003)
    Background & objectives: Antibodies with haemolytic properties are common within the ABO system. These lytic antibodies are immunoglobulin G (IgG) and in high titres cause haemolysis during blood transfusion. Information on Immunoglobulin types and concentration of ABO haemolysins in Indian population is lacking. The present study was undertaken to know the usefulness of haemolysin test for characterization of immunoglobulin class of ABO antibodies.Methods: Serum samples from 187 0 group blood donors were screened for A and B haemolysins. Thirty five samples were treated with dithiothretiol (DTT) for characterization of Ig class. Antibody titre was compared with grade of haemolysis.Results: Of the 51 strongly haemolytic serum samples, 32 (62.8%) had IgG titres of greater than or equal to64 after treatment with DTT. There was significant association (P<0.05) between grade of haemolysin and anti B IgG titre.Interpretation & conclusion: Haemolysin test was found to be a useful screening test to identify group 0 donors with high levels of IgG anti A and/or anti B for blood transfusion purposes.
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    Immune complex levels and plasmapheresis in Guillain-Barre syndrome.
    (Acta neurologica, 1993)
    Circulating IC levels were assayed serially in 12 G.B.S. patients treated with PE and an attempt was made to predict the outcome of treatment, from the levels of circulating IC. It was found that there was no significant correlation between the levels of circulating IC and the outcome of treatment with PE, in G.B.S. patients.
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    Irradiated blood components
    (INDIAN JOURNAL OF MEDICAL RESEARCH, 2005)
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    Morphological & ultrastructural changes of platelet concentrates stored in PVC bags
    (INDIAN JOURNAL OF MEDICAL RESEARCH, 1997)
    To assess the effect of storage bags on platelets, we studied the morphological and ultrastructural changes of samples drawn from platelet concentrates (PC) prepared and stored in triple, poly vinyl chloride (PVC) bags, manufactured in India. Using the scanning electron microscopy, we demonstrate formation of long pseudopods, and interaction through these to form aggregates. When platelets were stored at 23+/-2 degrees C, morphological changes were severe compared to the deleterious effects when kept at 22+/-0.5 degrees C. Ultrastructural analysis also showed that maintenance of discoid shape and prevention of granule secretion could be improved by storing the platelets at 22+/-0.5 degrees C. Significant degree of platelet fragmentation took place when the storage temperature was high. The morphology score done for platelets stored st both 22+/-0.5 degrees C and 23+/-2 degrees C showed that preservation of discoid shape was better with the former.
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    Normal human plasma anti-beta-glucoside antibody has markedly elevated IgA content and binds fungal and yeast polysaccharides
    (IMMUNOLOGICAL INVESTIGATIONS, 2007) Geetha, M; Annamma, KI; Mathai, J; Appukuttan, PS
    Normal human plasma antibody that recognizes beta-linked glucoside moiety was purified by affinity chromatography on cellulose. The anti-beta-glucoside antibody had three times higher IgA to IgG ratio and substantially higher polymeric IgA content than total serum immunoglobulins. Cellobiose and other beta-glucosides were best inhibitors of its binding to polystyrene microwell-coated polysaccharides. In synthetic glycoproteins made by conjugating disaccharides to hemoglobin or bovine serum albumin, cellobiose, unlike lactose or maltose, was sugar-specifically recognized by the antibody. It also recognized polystyrene well-coated beta 1 -> 3 linked glycans of Saccharomyces cerevisiae, Candida albicans and of barley in decreasing order of affinity. Its sugar-binding site could thus accommodate beta-glucoside with or without substitution at C4 and C3. High IgA content along with the capacity to bind common microbial and dietary antigens pointed to the immune inflammatory potential of the antibody.
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    On transfusion medicine
    (CURRENT SCIENCE, 1996) Mathai, J; Kutty, VR