Venkataraman BV

References (4)

Title : Species variation in the specificity of cholinesterases in human and rat blood samples - Venkataraman_1994_Ind.J.Physiol.Pharmacol_38_211
Author(s) : Venkataraman BV , Rani MA
Ref : Indian Journal of Physiology & Pharmacology , 38 :211 , 1994
Abstract : Acetylthiocholine iodide (ATC) as a common substrate in the combined assay of red blood cell cholinesterase (RBC ChE) and butyrylcholinesterase (BCHE) do not provide the accurate individual enzyme activities. Hence, in the present study the two enzyme activities in the same sample were assayed with the help of two different substrate, ATC and butyrylthiocholine iodide (BTC). Specificity of BTC towards BuCHE was found in blood, plasma and serum, while ATC is nonspecifically hydrolysed by both RBC ChE and BCHE. ATC gives significantly higher enzyme activity (P < 0.001) in rat plasma/serum and significantly lower enzyme activity (P < 0.0001; P < 0.001) in human plasma/serum. The possible reasons are discussed for substrate specity in various species in the assay of ChEs.
ESTHER : Venkataraman_1994_Ind.J.Physiol.Pharmacol_38_211
PubMedSearch : Venkataraman_1994_Ind.J.Physiol.Pharmacol_38_211
PubMedID: 7814085

Title : Correlation of time course of blood cholinesterase activity and toxic manifestations of acute methylparathion in antidote treated rats - Venkataraman_1994_Ind.J.Physiol.Pharmacol_38_214
Author(s) : Venkataraman BV , Rani MA , Andrade C , Joseph T
Ref : Indian Journal of Physiology & Pharmacology , 38 :214 , 1994
Abstract : Study was conducted to find out the correlation between red blood cholinesterase (RBC ChE) and plasma butyryl cholinesterase (BCHE) activities and toxic signs of oral methylparathion (MPT) and their recovery pattern with or without atropine treatment in female rats. Enzyme activity was estimated before and after an oral dose of MPT (7.5 mg/kg-1) at various time intervals upto 120 hr. Antidote groups received atropine (10 mg/kg-1, i.p.), either alone or with diazepam (2.5 mg/kg-1, i.p.), at the onset of toxic signs. Inhibition of enzyme activity served as definite index of acute toxicity of MPT. RBC ChE activity correlated with the intensity of toxic signs in no-antidote rats, while in atropine treated groups, there was no correlation. BCHE levels did not correlate with toxic signs in any of the groups except in the fatal group. The resynthesis of both the enzymes was complete in 120 hr study and did not synchronize with the recovery pattern of animals from toxic signs. Compared to BCHE, RBC ChE activity was found to be a more sensitive indicator for the diagnosis of severity of MPT toxicity.
ESTHER : Venkataraman_1994_Ind.J.Physiol.Pharmacol_38_214
PubMedSearch : Venkataraman_1994_Ind.J.Physiol.Pharmacol_38_214
PubMedID: 7814086

Title : Improved colorimetric method for cholinesterase activity - Venkataraman_1993_Ind.J.Physiol.Pharmacol_37_82
Author(s) : Venkataraman BV , Rani MA , Andrade C , Joseph T
Ref : Indian Journal of Physiology & Pharmacology , 37 :82 , 1993
Abstract : A modified colorimetric method for the estimation of cholinesterase activity has been worked out using two different substrates, acetylthiocholine iodide for total cholinesterase and a specific substrate, butyrylthiocholine iodide for pseudocholinesterase in the same sample. This is a modification of the method described by Voss and Sachsse (1970) wherein acetylthiocholine iodide was used for both total and pseudo cholinesterase activities. The pseudocholinesterase obtained with acetylthiocholine iodide was significantly higher (P < 0.0001) than that with butyrylthiocholine iodide either in whole blood or serum samples. Acetylthiocholine iodide while reacting with pseudocholinesterase in serum or plasma samples might also be interacting with the small quantities of acetylcholinesterase present. It is therefore suggested that butyrylthiocholine iodide and acetylthiocholine iodide may be used to determine pseudocholinesterase and total cholinesterase activities respectively. The use of two substrates with a few more alterations in the experimental conditions increased the validity of this simple and rapid colorimetric method.
ESTHER : Venkataraman_1993_Ind.J.Physiol.Pharmacol_37_82
PubMedSearch : Venkataraman_1993_Ind.J.Physiol.Pharmacol_37_82
PubMedID: 8449554

Title : Erythrocyte and plasma cholinesterase activity in normal pregnancy - Venkataraman_1990_Indian.J.Physiol.Pharmacol_34_26
Author(s) : Venkataraman BV , Iyer GY , Narayanan R , Joseph T
Ref : Indian Journal of Physiology & Pharmacology , 34 :26 , 1990
Abstract : Erythrocyte acetylcholinesterase and plasma cholinesterase was estimated in 50 normal pregnant women and 22 age matched normal non-pregnant women. Plasma cholinesterase was significantly decreased while erythrocyte cholinesterase was significantly increased during pregnancy. These changes may be related to altered haemodynamics and or other inter-related changes occurring in pregnancy.
ESTHER : Venkataraman_1990_Indian.J.Physiol.Pharmacol_34_26
PubMedSearch : Venkataraman_1990_Indian.J.Physiol.Pharmacol_34_26
PubMedID: 2361719