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Biomedical subjects

S Bharathi

Publications and source records attributed to S Bharathi.

16 recordsLinked to original sources
PubMed2001

A glucose biosensor based on electrodeposited biocomposites of gold nanoparticles and glucose oxidase enzyme.

Electrodeposition was used for the codeposition of glucose oxidase enzyme and a gold nanoparticle-silicate network onto an indium tin oxide (ITO) glass electrode. This co-entrapment of glucose oxidase enzyme in a gold nanoparticle-silicate network imparts biocatalytic activity to the film. The gold nanoparticles in the network catalyse the oxidation and reduction of H2O2, the by-product of the enzymatic reaction. The low operating potential of the sensor eliminates the interference from common interferents, such as acetaminophen, ascorbic acid, dopamine, etc.

Journal Article↗
PubMed1999

Deconvolution of the fluorescence spectra into its component Gaussians: a method to analyze the binding of coumarin to bovine serum albumin.

7-N,N-Diethylamino-4-methylcoumarin, (cou-1), a readily available laser dye binding to bovine serum albumin (BSA), at room temperature has been studied by steady state fluorescence spectroscopy. Existing methods of analysis of the binding to obtain the binding parameters are based on the change in fluorescence intensity at a particular wavelength. These methods are not convenient when there is a gradual shift in the emission maxima for increasing protein concentration. In this paper we present a method to obtain the binding constants of cou-1 to BSA using a Windows '95 based package to deconvolute the asymmetrical spectrum (fluorescence intensity versus wave number curve) into two Gaussians, each corresponding to the binding of the fluorophore to a particular site. This method is convenient to analyze the binding constant data and obtain the binding parameters of each binding site, and can also provide information about the microenvironment of each site, relating micropolarity and microviscosity.

Coumarins↗
PubMed1995

Inhibition of cleavage by restriction endonucleases due to modifications induced in SV40 DNA by methyl methanesulfonate.

Methyl methanesulfonate (MMS), a direct mutagen, methylates DNA bases and causes distortions in DNA structure. Supercoiled SV40 DNA was treated in vitro with varying concentrations of MMS from 0.001 mM to 10 mM MMS either for 30 min or 3 h and analysed by electrophoresis in 1% neutral and alkaline agarose gels. The electrophoretic mobility (EPM) of native DNA did not change after treatment with the mutagen, while alkaline gels revealed low MW DNA fragments due to single strand breaks at alkali-sensitive sites generated by the action of MMS. By two-dimensional electrophoresis, we find that all three native DNA forms contain alkali-sensitive sites after treatment with MMS. To examine the effect of base modification by MMS on DNA-protein interactions, we have used as probes, restriction endonucleases. These cleave DNA in a sequence-specific manner, and their activity is dependent upon the methylation status of the substrate DNA. We find that cleavage by these restriction endonucleases is inhibited due to methylation by MMS.

DNA Damage↗
PubMed1994

Unilocular cystic sebaceous lymphadenoma of the parotid gland.

Unilocular Cystic Sebaceous Lymphadenoma of the parotid gland also described as benign lymphoepithelial parotid cyst with sebaceous differentiation is an unusual tumour which histogenetically resembles Warthin's tumour. We present two such cases reported in the department of Pathology, Kasturba Medical College with review of the literature on histogenesis.

Adult↗
PubMed1990

Effect of altered ventilations on human spinal and supra spinal reflexes.

The present study was aimed at evaluating the alterations in the human reflexes brought about by briefly altered ventilations. In 20 healthy young male volunteers, the H reflex and blink reflex were studied during normal ventilation, voluntary hypoventilation and voluntary hyperventilation. The latencies of these reflexes were compared. It was observed that the amount of altered ventilations used in the present study could not produce any significant change in these reflexes except in the case of the early response of the blink reflex.

Adolescent↗
PubMed1990

Electrophysiological studies on human phrenic nerve & diaphragm.

To determine normal values for phrenic nerve stimulation, the phrenic nerve was stimulated transcutaneously in 22 healthy adolescent male volunteers. The phrenic latency, amplitude and duration of the evoked diaphragm action potential (EDAP) were noted. Maximum mouth inspiratory pressure (MMIP) and maximum ventilation volume (MVV) were also measured to evaluate the maximal strength of the diaphragm. No significant correlations were observed between EDAP and the parameters of diaphragm strength. The correlation coefficient between the amplitude-duration product of EDAP (integral EDAP) and MMIP was +0.15 and it was +0.29 between the integral EDAP and MVV.

Action Potentials↗
PubMed1990

Proliferating trichilemmal tumours.

Twelve cases of a peculiar, relatively uncommon, benign but locally invasive proliferating trichilemmal tumours are reported. The origin of these tumour appears to be outer root sheath of hair. In order to avoid an erroneous diagnosis of squamous cell carcinoma, an adequate knowledge of these tumours is necessary.

Adult↗
PubMedDate not supplied

Sol-gel-derived prussian blue-silicate amperometric glucose biosensor.

A new type of inorganic biosensor is introduced. The sensor comprises glucose oxidase enzymes encapsulated in a sol-gel-derived Prussian blue-silicate hybrid network. Glucose is detected by the biocatalytic reduction of oxygen followed by catalytic reduction of hydrogen peroxide by the Prussian blue catalyst. The sol-gel silicate entails a rigid encapsulating matrix, the Prussian blue provides chemical catalysis and charge mediation from the reduction site to the supporting electrode, and the enzyme is responsible for the biocatalysis. The feasibility of a dual optical/electrochemical mode of analysis is also demonstrated.

Biosensing Techniques↗
PubMedDate not supplied

Effects of central administration of insulin in normal and VMH (ventromedial hypothalamus) lesioned rats on food intake.

Central effects of insulin on 20 min. food intake were studied in rats. Insulin administration in the lateral ventricular cerebrospinal fluid (CSF) did not alter food intake in the intact or lesioned ventromedial hypothalamus (VMH) rats. Whereas, after insulin injection in VMH there was a decrease in food intake. In VMH lesioned rats, subcutaneous injection of insulin increased food intake.

Animals↗
PubMedDate not supplied

The standardized distal motor latencies and the peak to peak amplitudes of evoked muscle action potentials in the extremities of humans.

The values of Standardized Distal Motor Latency (SDML) of Median, Ulnar and Common Peroneal nerves and the peak to peak amplitude of Evoked Muscle Action Potentials (EMAP) of the small muscles of the limbs were studied in 50 normal subjects. The SDML values showed significant sex difference, whereas no sex difference was observed in the amplitude of the EMAPs.

Action Potentials↗