Biomedical subjects

V Meera

Publications and source records attributed to V Meera.

5 recordsLinked to original sources

PubMed2006

Surface modification of polystyrene using polyaniline nanostructures for biomolecule adhesion in radioimmunoassays.

The selection of an appropriate surface as a solid phase for coupling antibodies is a critical step in the development of solid-phase immunoassays. Availability of a new method of preactivating the surface of polystyrene tubes with a layer of another polymer for enhanced immobilization of antibodies seems to be promising. In this paper, we report the activation of a polystyrene surface using a layer of polyaniline and its effect on immobilizing antibodies for use as a solid phase in a T3 immunoassay. The modified surface on the polystyrene was characterized by optical absorption, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The modified tubes were coated with antibody and evaluated for their performance in the assay and validated for radioimmunoassay of T3. AFM images of the modified surface showed an enhancement in the surface roughness (Ra of 20.2 nm), as compared to an unmodified surface (Ra of 6 nm), allowing more adsorption of antibodies to the surface. XPS revealed the presence of N (binding energy approximately 400 eV) on the modified surface, which could help the antibody molecules to bind to these preactivated (modified) tubes. The modified tubes, when coated with antibody, not only showed an increase in the binding with the radioiodinated tracer but also improved the precision of coating the antibody. The present method of activating polystyrene surfaces is simple, does not involve severe chemical treatment, and may have wide applicability to functionalize other supports for immobilizing biomolecules.

Adhesiveness↗

PubMed2005

Development of coated tubes RIA for serum T3 (tri-iodothyronine) for production scale.

A coating procedure that could provide immobilization of antibodies, with increased binding capacity, that is cost effective, simple, robust, and appropriate for production scale application, is described. This coating approach of T3 antibodies to the polystyrene tubes has been systematically investigated to determine its utility for the development of coated tube Radioimmunoassay (RIA) for T3 in human serum. Further, the results obtained by the developed coating procedure are found to be comparable with those obtained by the "gold standard," the liquid phase RIA for T3. The coating procedure is completed in three major steps, each step involving an overnight incubation. The normal rabbit gamma-globulins are physically adsorbed onto the polystyrene tubes and incubated. After washing, a second antibody (goat anti-rabbit antiserum) is added and incubated. To this antigen specific antibody is added (T3 antibody produced in rabbit) and further incubated. Finally, the non-specific sites on the tubes are saturated by the blocking solution. The concentration of normal rabbit globulin, titers of second antibody and T3 antibody, and time required for coating are optimized to arrive at a suitable coating protocol. The coated tubes were evaluated for precision, reproducibility, and stability. Various parameters such as total reaction volume, incubation time and temperature, total number and volume of washings, concentration of 8-anilino-1-naphthalene sulfonic acid (ANS), and quantity of tracer per tube are optimized to arrive at a suitable standard curve. The optimized assay is validated for the quality control parameters such as intra- and inter-assay variations, recovery, and parallelism. The developed coated tubes assay had an assay range of 0.3-4.8 ng/mL with a sensitivity of 0.3 ng/mL at 90% B/B0. Batch to batch variation in coating was < 10%. The coated tubes were stable up to 1 year, which is adequate for production scale.

Animals↗

PubMed2003

188Re-labeled hydroxyapatite particles for radiation synovectomy.

A new procedure for labeling hydroxyapatite (HA) particles with 188Re for radiation synovectomy is described and standardized. The particles were labeled with 188Re in high yields (99%) in acidic medium. HA particle size remained unaffected by reaction conditions as checked by laser diffraction particle analyzer. 188Re-HA was found to be stable retaining 99% radiochemical purity after 4 days when stored in ascorbic acid solution (10mg/ml, pH 5). Intra-articular injection in rats revealed approximately 98% retention of 188Re-HA in the knee after 48-h pi.

Animals↗

PubMed2001

Discriminative value of lipids and apolipoproteins in alcoholics.

1. It is important to detect alcohol use in its early stages so that interventions can be planned effectively. In a bid to screen for alcohol use disorders various biochemical assessments have been advocated. 2. It has been seen that moderate to heavy alcohol consumption appears to elevate ApoA1 though the effect of alcohol consumption on ApoB is not well defined. 3. Present study was planned to evaluate the contribution of lipid profile and lipoprotein measures for the diagnosis of alcohol use disorder in 75 alcohol dependent and 45 normal healthy controls. 4. Based on the TC, TG, HDL/LDL-c, HDL-c/TC, ApoA1, ApoB, and ApoA1/ApoB a discriminant equation was developed for classification of alcohol dependent users (alcoholics) and non-users (non-alcoholics) 5. The discriminant equation resulted in 84.7% of subjects being correctly classified. (94.7% in non-users and 81.1% in alcohol dependent users as alcoholics).

Adult↗

PubMed1991

An enzymeimmunoassay method for thyroxine determination in serum samples.

Here we describe an enzymeimmunoassay (EIA) for thyroxine (T4) in serum, whose performance is comparable to that of a sensitive T4 radioimmunoassay (RIA). In this assay, specific T4 antibody adsorbed on polystyrene beads is used along with T4-horseradishperoxidase as the tracer and omicron-phenylenediamine as chromogen. Several samples were analysed both by this T4 EIA and by using a commercial RIA kit for T4. The results correlate well with a correlation coefficient r = 0.9 and slope = 0.93 (n = 50).

Humans↗