PubMed Health⌕ Search

Biomedical subjects

R C Trivedi

Publications and source records attributed to R C Trivedi.

4 recordsLinked to original sources
PubMed1996

Determination of lead, zinc, potassium, calcium, copper and sodium in human cataract lenses.

Concentrations of Pb, Zn, K, Ca, Cu and Na were determined in several human cataract and clear lenses, obtained from patients from two contrasting environmental regions in India, and the values were compared. When compared with the results obtained for samples of clear lenses, the mean concentration values of cataract lenses showed significant changes on the basis of the Mann-Whitney test. In cataract lenses, Pb and Zn showed an inverse correlation of r = -0.83; y = -1.64x + 457. Ca and K also showed an inverse correlation of r = -0.71; y = -0.34x + 3.6. No significant correlations were found between any other elements. The distribution of Pb, Zn, Ca and K were studied and their importance in ocular tissues is discussed. The molecules present in the eye lens lattice have undergone some conformational alterations due to intrusion of Pb and Ca ions and extrusion of Zn and K ions through the process of ion-exchange, thereby influencing the transparency of the lens.

Aged↗
PubMed1978

New ultraviolet (340 nm) method for assay of uric acid in serum or plasma.

We propose a novel enzymatic method for assay of uric acid at 340 nm, which eliminates several disadvantages of both the colorimetric and enzymatic methods now in common use. Here, uric acid is catalytically oxidized to allantoin and hydrogen peroxide. The peroxide is reacted with ethanol in the presence of catalase to form acetaldehyde and water, and the acetaldehyde is reduced by NADH in the presence of alcohol dehydrogenase to ethanol. The decrease in absorbance at 340 nm caused by oxidation of NADH is directly proportional to the concentration of uric acid in the sample. Measurement of the change in absorbance between 20 and 200 s eliminates the need for a serum blank measurement. Absorbance and concentration are linearly related to 120 mg of uric acid per liter. The new method was compared with the uricase method in which decomposition of uric acid at 293 nm is directly measured. The results for the 47 patients' sera so examined can be expressed by the linear equation y340 = 1.0078x293 + 0.122 (r = 0.9984).

Alcohol Oxidoreductases↗
PubMed1978

New enzymatic method for serum uric acid at 500 nm.

We describe a manual method, well suited to mechanization, for quantitating serum uric acid at 500 nm. In the assay mixture (0.10 ml of sample and 3.00 ml of reagent) the hydrogen peroxide produced from uric acid by uricase is coupled with p-hydroxybenzoate and 4-aminoantipyrine in the presence of peroxidase to form a colored complex, which is measured. A separate sample blank is obviated by taking an initial absorbance measurement 20 s after the sample is added. The reaction is complete within 5 min; its sensitivity is 0.001 deltaA/mg per liter. Absorbances are linearly related to uric acid concentrations up to 120 mg/liter. Many substances that may be present in normal serum do not interfere, but bilirubin in moderately above-normal concentrations will interfere. The procedure can be modified to largely correct for this, when necessary. The proposed method (y) correlated well (r = 0.979) with the uric acid 293 nm reference method (x) and the relation is described by the equation y = 0.998x + 2.42.

Humans↗