Krishnakumari MK

References (8)

Title : Cytotoxicity of certain organic solvents and organophosphorus insecticides to the ciliated protozoan Paramecium caudatum - Rajini_1989_Microbios_59_157
Author(s) : Rajini PS , Krishnakumari MK , Majumder SK
Ref : Microbios , 59 :157 , 1989
Abstract : Responses of Paramecium caudatum, a ciliated protozoan, to acute exposures of certain organic solvents and organophosphorus insecticides (OPI) were studied by determining their lethal concentration (10 min-LC100) and median lethal concentration (4 h-LC50). The solvents and OPI evoked a distinct sequence of responses. Among the five solvents tested, acetone proved most toxic [LC-2.9% and LC50-0.68% (v/v)], while dimethyl sulphoxide (DMSO) showed least toxicity [LC-11.0% and LC50-3.16% (v/v)]. The order of toxicity of solvents was: acetone greater than ethanol greater than methanol greater than N, N-dimethylformamide greater than dimethylsulphoxide. The LC values of six OPI dissolved in either acetone or DMSO indicated that they were more toxic when dissolved in acetone and least toxic in DMSO. Among the OPI, bromophos proved most toxic (LC-10 ppm) while malathion showed least toxicity (LC-200 ppm) in DMSO. The order of toxicity of OPI was: bromophos greater than pirimiphos-methyl greater than parathion methyl greater than dichlorvos greater than fenitrothion greater than malathion. The 4 h-LC50 values computed for bromophos and malathion (dissolved in DMSO) were 575 ppb and 19.9 ppm, respectively, indicating the high susceptibility of P. caudatum to bromophos. The results indicate that the Paramecium toxicity assay could be used as a complementary system to rapidly elucidate the cytotoxic potential of compounds.
ESTHER : Rajini_1989_Microbios_59_157
PubMedSearch : Rajini_1989_Microbios_59_157
PubMedID: 2593868

Title : Inhibitory pattern of tissue esterases in rats fed dietary pirimiphos- methyl - Rajini_1989_J.Environ.Sci.Health.[B]_24_509
Author(s) : Rajini PS , Muralidhara , Krishnakumari MK
Ref : J Environ Sci Health [B] , 24 :509 , 1989
Abstract : Activities of Acetylcholinesterase (AChE) in brain and erythrocytes, pseudocholinesterase (PChE) in plasma and non-specific carboxylesterase (NSE) in brain, liver, plasma and kidney were assayed at weekly intervals in growing male rats fed dietary pirimiphos-methyl at dosages of 1000, and 1500 ppm for a period of 28 days. Significant inhibition of tissue esterases were observed at the end of 7 days at both the dosages and the enzyme activities remained markedly inhibited at subsequent intervals. Activities of all enzymes (excepting Brain AChE) returned to normal levels following a 7-day maintenance on the insecticide-free diet implicating that pirimiphos-methyl induced little or no permanent tissue damage. The results suggest that plasma NSE level may also serve as a sensitive indicator in monitoring OPI exposure.
ESTHER : Rajini_1989_J.Environ.Sci.Health.[B]_24_509
PubMedSearch : Rajini_1989_J.Environ.Sci.Health.[B]_24_509
PubMedID: 2600363

Title : Toxicity of pirimiphos-methyl: I. The acute and subacute oral toxicity in albino rats - Rajini_1988_J.Environ.Sci.Health.[B]_23_127
Author(s) : Rajini PS , Krishnakumari MK
Ref : J Environ Sci Health [B] , 23 :127 , 1988
Abstract : In an acute study, albino rats of both sexes were orally administered graded doses of Pirimiphosmethyl, and the statistically computed median lethal dose (LD-50) were 1861 and 1667 mg/kg body weight for male and female rats respectively. No treatment related changes were discernible with regard to food intake, growth, gross or histopathology of the organs. In a time-course study, the correlation between symptoms and degree of esterase inhibition was examined in rats administered the minimum lethal dose (MLD: 1000 mg/kg b.w.) of the insecticide. Time-course inhibition pattern of both cholinesterase (ChE) and non-specific carboxylesterase (NSE) activities in brain and plasma revealed maximum inhibition at 24 h post-treatment which correlated well with the intensity of symptoms. In a subacute study, groups of male rats were fed dietary Pirimiphos-methyl at 0, 10, 250, 500 and 1000 ppm for 28 days. Food consumption and growth rate were not affected throughout the experimental period. At necropsy after 28 days, no gross pathological changes were seen in any of the organs except a slight increase in liver weight at 1000 ppm. Though no statistical differences were observed in the levels of hepatic transaminases, a significant increase in serum transaminase was evident. Significant increase in the activities of hepatic ALP, beta-GLR and serum ALP were evident at 500 and 1000 ppm. Further, significant inhibition of plasma PChE was evident at 250, 500 and 1000 ppm while the degree of inhibition of brain AChE was significant only at the higher dosages. No histopathological alterations were observed in any of the organs.
ESTHER : Rajini_1988_J.Environ.Sci.Health.[B]_23_127
PubMedSearch : Rajini_1988_J.Environ.Sci.Health.[B]_23_127
PubMedID: 3385133

Title : Toxicity of pirimiphos-methyl: II. Effect of dietary feeding on blood and urine constituents in albino rats - Rajini_1988_J.Environ.Sci.Health.[B]_23_145
Author(s) : Rajini PS , Krishnakumari MK
Ref : J Environ Sci Health [B] , 23 :145 , 1988
Abstract : Growing male rats were fed dietary Pirimiphos-methyl at 0, 500, 1000 and 1500 ppm for 28 days and selected blood and urine constituents were measured at weekly intervals. Dietary intake of Pirimiphos-methyl induced an initial, transient hypoglycemia and a marked elevation in blood urea at all dosages. Though it did not produce any significant change in the urine output initially, marked oliguria was observed after 12 days of feeding. The alterations observed in urine constituents were: increased urea, proteinuria, transient increase in creatinine and significant increase in the excretion of glucuronic acid and ethereal sulfate at all intervals. However, since no pathological alterations were evident in the kidney, the anomalous urinary excretion of various body constituents might be due to the anticholinesterase action of the insecticide at the central nervous system.
ESTHER : Rajini_1988_J.Environ.Sci.Health.[B]_23_145
PubMedSearch : Rajini_1988_J.Environ.Sci.Health.[B]_23_145
PubMedID: 3385134

Title : Response of blood and brain cholinesterase to dermal exposure of bromophos in the rat - Shivanandappa_1988_Toxicology_48_199
Author(s) : Shivanandappa T , Joseph P , Krishnakumari MK
Ref : Toxicology , 48 :199 , 1988
Abstract : Response of cholinesterase to dermal exposure of acute, single and multiple doses of Bromophos in the female rat has been studied. Dose-response studies (50-4000 mg/kg body weight, 24 h exposure) showed that plasma cholinesterase was most sensitive to inhibition in vivo, followed by the brain and erythrocyte acetylcholinesterase. The ID50 values for the in vivo cholinesterase inhibition were 10.1, 576.1 and 1938.0 mg/kg body weight for the plasma, brain and erythrocytes, respectively. In time-course studies after a single sublethal dose of 1000 mg/kg body weight (24 h) of Bromophos, the serum and brain cholinesterase were rapidly inhibited reaching a maximum at 16 h. Recovery was complete in the case of serum at 14 days post-exposure, whereas the brain enzyme was not fully recovered at 21 days. In a subacute study, daily dermal application of 50 mg/kg body weight of Bromophos for 5 and 10 days, resulted in high inhibition of the serum cholinesterase and brain acetylcholinesterase, the former being more marked which was reversible after 10 or 15 days of post-exposure period. Very low levels of dermal exposure of Bromophos (10-50 mg/kg body weight) for 17 days caused pronounced depression of serum cholinesterase which completely recovered in 15 days after cessation of exposure suggesting that the serum cholinesterase could serve as the most sensitive diagnostic indicator of Bromophos exposure.
ESTHER : Shivanandappa_1988_Toxicology_48_199
PubMedSearch : Shivanandappa_1988_Toxicology_48_199
PubMedID: 3341046

Title : Effect of pirimiphos-methyl, an organophosphorus insecticide on hematological parameters in albino rats -
Author(s) : Rajini PS , Viswanatha S , Krishnakumari MK
Ref : Indian J Exp Biol , 25 :190 , 1987
PubMedID: 3666818

Title : Mutagenic properties of pirimiphos-methyl in male mice -
Author(s) : Rajini PS , Muralidhara , Krishnakumari MK , Majumder SK
Ref : Bulletin of Environmental Contamination & Toxicology , 36 :680 , 1986
PubMedID: 3708170

Title : Effect of L-ascorbic acid supplementation on the toxicity of pirimiphos- methyl to albino rats - Rajini_1985_Int.J.Vitam.Nutr.Res_55_421
Author(s) : Rajini PS , Krishnakumari MK
Ref : Int J Vitam Nutr Res , 55 :421 , 1985
Abstract : The effect of L-ascorbic acid supplementation on Pirimiphos-methyl induced toxicity was studied in albino rats. Biochemical estimations were made in rats administered orally the insecticide at 100 and 200 mg/kg body weight with or without oral supplementation of L-ascorbic acid at 200 mg/kg b.w. The biochemical assessments included estimations of brain and plasma cholinesterases, levels of ascorbic acid in liver, kidney and adrenals, urinary levels of ascorbic acid and glucuronic acid. A lower degree of inhibition of the cholinesterases were evident in ascorbic acid supplemented rats. Marked elevation in urinary levels of ascorbic acid and glucuronic acid was observed in the insecticide treated rats. Results of this study suggests that L-ascorbic acid supplementation partially offsets Pirimiphos-methyl induced toxicity.
ESTHER : Rajini_1985_Int.J.Vitam.Nutr.Res_55_421
PubMedSearch : Rajini_1985_Int.J.Vitam.Nutr.Res_55_421
PubMedID: 4086212