Biomedical subjects
D Ramana
Publications and source records attributed to D Ramana.
Quantitation of epsilon-amino group using amino acids as reference standards by trinitrobenzene sulfonic acid. A simple spectrophotometric method for the estimation of hapten to carrier protein ratio.
A simple, sensitive and direct spectrophotometric method is presented for the determination of epsilon-amino groups of L-lysine present in carrier proteins, using the free amino acids L-lysine and L-glutamic acid as reference standards, and 2,4,6-trinitrobenzene 1-sulfonic acid (TNBS) reagent. The amount of epsilon-amino group present in the carrier protein after coupling with hapten is directly quantitated using the standard curve generated by the difference in absorbance observed with L-lysine and L-glutamic acid after their reaction with TNBS reagent. Spectral analysis of L-lysine and L-glutamic acid (27.36 nmol) derivatives of TNBS at 335 nm showed that TNP-L-lysine had twice the absorbance of TNP-L-glutamic acid, since TNBS reagent interacts equally with the alpha-amino and epsilon-amino groups present in L-lysine and the alpha-amino group of L-glutamic acid, respectively. The relationship between absorbance and concentration of epsilon-amino groups (up to 16 micrograms/ml) was found to be linear. The number of epsilon-amino groups of lysine present in carrier proteins such as BSA, HSA, thyroglobulin and the enzyme, horseradish peroxidase, were analyzed by the present method and were found to be similar to the reported values. Various carrier protein-hapten conjugates (protein-mycotoxin/vitamin/steroid hormone conjugates) were made and analyzed by the method developed in order to determine their mole to mole ratio.
Therapeutic action of acetylcholine in malathion toxicity.
Administration of malathion to the developing Philosamia ricini larvae induces accumulation of acetylcholine, marked inhibition of acetylcholinesterase activity, depletion of all nutrients, heavy weight loss and high mortality. Pre-treatment of the larvae with acetylcholine via feed, reduces malathion toxicity and conversely, feeding of acetylcholine to malathion-treated larvae reverses the toxic effects. Resumption of normal control feed to malathion-treated insects results in higher mortality than in insects fed acetylcholine after exposure to malathion. This emphasizes the therapeutic action of acetylcholine. Feeding of a mixture of equal quantities of malathion and acetylcholine recorded significantly lower mortality among insects in comparison to those fed malathion alone. This further supports the protective action of acetylcholine. Reversal of malathion toxicity and the protective action of acetylcholine have been attributed to the mediation of choline, an essential insect vitamin that gets released as a catabolic product of acetylcholine.
Role of rice and cereal products in dietary cadmium and lead intake among different socio-economic groups in south India.
A study was conducted to evaluate the concentration of cadmium and lead in rice and cereal products commonly consumed in South India. Samples from retail outlets were purchased and analysed for cadmium and lead using graphite tube atomic absorption spectrophotometry. The results indicated varying concentrations of these metals in different rice and cereal products. The daily dietary intake of cadmium and lead varied among different socio-economic groups, based on occupation, and choice of consumption. The findings suggest that rice is the major source of cadmium and lead among the rural population and economically-deprived class. The source of intake of toxic metals appears to be more diverse in the case of the urban middle class and the economically privileged class of South India.