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Biomedical subjects

R L Gupta

Publications and source records attributed to R L Gupta.

At least 19 recordsLinked to original sources
PubMed2002

Mutagenicity of sulfoscanate: a comparative study.

The mutagenic activity of sulfoscanate (SSC) (4-isothiocyanate-4'-nitrodiphenyl sulphide) has been compared with that of the following reported drugs: (a) nitroscanate (NSC) (4-isothiocyanate-4'-nitrodiphenyl ether) which is a veterinary anthelmintic drug and (b) amoscanate (ASC) (4-isothiocyanate-4'-nitrodiphenyl amine) which is effective against schistosomes. SSC has been found to be a very potent mutagen towards TA98 and TA100 inducing 26.0 and 475.5revertants/nmole, respectively. NSC was found to induce mutations at a rate of 11.1 and 21.5revertants/nmole in TA98 and TA100, respectively. ASC was found to be non-mutagenic as such, but the urine of animals given the drug displayed mutagenicity. When SSC was tested in TA98/1,8-DNP(6), deficient in O-acetyltransferase, the activity decreased to 10.0revertants/nmole. However, in case of NSC the mutagenic activity was reduced to 0.24revertants/nmole, indicating the importance of O-acetyltransferase in generating N-acetoxyarylamine. In TA98NR, deficient in nitroreductase, the mutagenicity of SSC and NSC was totally absent. The positional isomers of SSC, 4-isothiocyanate-3'-nitro- and 4-isothiocyanate-2'-nitrodiphenyl sulphide, were found to be non-mutagenic in both TA98 and TA100. Our comparison of the mutagenic activity of SSC, NSC and ASC indicates that the pattern of activity is SSC>NSC>ASC.

Diphenylamine↗
PubMed2001

Effect of various alkyl and unsaturated substituents on the mutagenicity of some nitrophenyl thioethers.

A variety of nitro-substituted phenyl alkyl/aryl thioethers and nitroso-substituted phenyl alkyl/aryl thioethers have been synthesized and tested for their mutagenicity towards Salmonella typhimurium strain TA100, TA98, TA98NR and TA98/1,8-DNP(6) in the absence of S9 mix. The relative order of mutagenicity in TA98 and TA100 among p-nitrophenyl thioethers having alkyl or aryl substituents is allyl>phenyl>benzyl>butyl>propyl>ethyl>methyl. Compounds having an alkyl chain C(6) to C(12) were found to be non-mutagenic. Among the various positional isomers (ortho, meta and para) of nitro-substituted diphenyl thioethers only the compounds having the -NO(2) function at the para position is mutagenic, whereas compounds having a -NO(2) function at ortho and meta are non-mutagenic. However, the reduced intermediate, ortho-nitroso derivative was found to be mutagenic in all the four strains but the meta-nitroso derivative was found to be non-mutagenic. All mutagens were found to be non-mutagenic when tested in nitroreductase deficient strain TA98NR, whereas their nitroso intermediates are found to be mutagenic. A substantial fall in the mutagenic activity is observed when some mutagens are tested in O-acetyltransferase deficient strain TA98/1,8-DNP(6).

Mutagenicity Tests↗
PubMed2000

In vitro antioxidant activity of piperine.

Oxygen radical injury and lipid peroxidation have been suggested as major causes of atherosclerosis, cancer, liver disease and the aging process. Piperine, having an antiinflammatory effect, has been demonstrated in in vitro experiments to protect against oxidative damage by inhibiting or quenching free radicals and reactive oxygen species and hydroxyl radicals. The effect on lipid peroxidation was also examined and IC50 values were calculated. Piperine was found to act as a hydroxyl radical scavenger at low concentrations, but at higher concentrations, it activated the fenton reaction resulting in increased generation of hydroxyl radicals. Whereas it acts as a powerful superoxide scavenger and IC50 is 1.82 mM, a 52% inhibition of lipid peroxidation was observed at a dose of 1400 microM with an IC50 of 1.23 mM. The results depict that piperine possesses direct antioxidant activity against various free radicals. This study also opens newer views on the potential efficacy of piperine in protecting tissues from peroxidative damage.

Alkaloids↗
PubMed1999

Solitary cellular schwannoma (neurilemmoma) showing malignant changes: evaluation through magnetic resonance imaging (M.R.I.), surgical intervention, and histopathology.

Schwannoma (neurilemmoma) are common benign tumors arising from the peripheral nerve sheath. Malignant transformation is uncommon. A unique case showing such a transformation is reported highlighting the roles of magnetic resonance imaging, surgical intervention, and histopathology. The case was thoroughly investigated by learning the details of the sequence of events leading to the current status. The evaluation was made through magnetic resonance imaging. In addition, computed tomography and conventional radiography were used to locate any foci of calcification. Subsequently, the tumor's gross and microscopic morphology was defined by surgical intervention and histopathology. Malignant schwannoma of the left leg occupying the entire calf is extremely uncommon. Only ten cases have been reported thus far, including the current one from the Indian subcontinent. Malignant transformation in a schwannoma differs significantly from malignant nerve sheath tumors (erroneously called malignant schwannomas). An endeavour has been made to differentiate malignant transformation in schwannoma from other malignant peripheral nerve sheath tumors. An innovation in this direction is magnetic resonance imaging. This investigate procedure is imperative in such situations, along with surgery and histopathology, which may also help in classifying the condition.

Humans↗
PubMed1999

Open labelled evaluation of injection Manyana (a combination of diclofenac + pitofenone + fenpiverinium) in ureteric, biliary and intestinal spasm--a preliminary report.

To study the efficacy and safety of a parenteral formulation of 'Manyana' (a combination of diclofenac + pitofenone + fenpiverinium) in ureteric, biliary and intestinal colic, an open labelled study was conducted at two centres. A total of 206 patients were enrolled and evaluated for decrease in pain with time on a visual analogue scale. A statistically significant difference was observed in pain within 30 minutes of drug administration and the pain relief lasted for as long as 24 hours post dosing. The study shows definite synergism between the antispasmodics pitofenone and fenpiverinium with the NSAID-diclofenac, reducing the prostaglandin levels and also the spasm related to colic.

Adolescent↗
PubMed1999

Double blind, randomised, parallel, prospective, comparative, clinical evaluation of a combination of antispasmodic analgesic Diclofenac + Pitofenone + Fenpiverinium (Manyana vs Analgin + Pitofenone + Fenpiverinium (Baralgan) in biliary, ureteric and intestinal colic.

In this double blind, prospective study, the relative efficacy of Diclofenac + Pitofenone + Fenpiverinium (Manyana) and Analgin + Pitofenone + Fenpiverinium (Baralgan) in 200 patients of biliary, ureteric and intestinal colic was evaluated. Patients were given these coded drugs thrice daily for five days starting from day 0 to day 5. The results of the present clinical evaluation demonstrated that Manyana appeared to be superior to Baralgan in biliary and ureteric colic while it was therapeutically equivalent to Baralgan in reducing the pain intensity in intestinal colic. Both the medications were tolerated well and there were no side-effects reported.

Adolescent↗
PubMed1998

Malignant chondroid syringoma.

Malignant chondroid syringoma (MCS) is a rare tumor, of the sweat gland; only a few hundred such cases are reported in literature. A female presented with a subcutaneous swelling on the scalp with repeated recurrence and positive regional lymph nodes. Adequate planning for the treatment of this case was possible as preoperative diagnosis of MCS was documented by fine needle aspiration cytology (FNAC). The case was successfully managed with a multimodal approach, which included radical surgery and subsequent radiotherapy. The patient is symptom free after 25 months. The possibility of this type tumor should be entertained when multiple recurrences occur following adequate excision. FNAC has a definitive role in planning rational therapy.

Adult↗
PubMed1998

"Changing trends (clinico-biochemical) in gall-bladder stone disease"--an observation.

Present study has been undertaken to know the causative factors responsible for change in trend of gall-stone disease from middle aged, fertile, fat females to young asthenic females in twenties. Our findings reveal high incidence of gall stone formation in non-obese young females. Average fat consumption in non-obese patients was less (17%) than that of obese (26%). However, use of oral contraceptives was high in non-obese females and maximum users were in young age group while in obese in middle age group. Bilirubin content in gall bladder stones of non-obese was significantly more than that of obese (p < 0.01) whereas cholesterol content in gall bladder stones of obese was significantly high when compared to non-obese subjects. Analysis of bile showed significant increase in bilirubin and calcium level of non-obese when compared to control and obese subjects whereas phosphorus levels were significantly decreased in the bile of non obese subjects. These findings suggest that in non-obese females less intake of fat, early use of oral contraceptives, higher contents of bilirubin and calcium and low content of phosphorus in bile may be responsible for gall stone formation.

Adult↗
PubMed1997

Nitroreductase independent mutagenicity of 1-halogenated-2,4-dinitrobenzenes.

The 1-halogen substituted 2,4-dinitrobenzenes have been found to be mutagenic in Salmonella TA98 with an activity order of 1-fluoro > 1-chloro > 1-bromo > 1-iodo. This specific activity was not lowered in the nitroreductase deficient strain TA98NR and O-acetyltransferase deficient strain TA98/1,8-DNP6, indicating that the mutagenicity of these compounds is not dependent upon -NO2 reduction to -NHOH and its subsequent esterification. The activity was, rather, higher in the former and remained almost equal in the latter strain compared to TA98, suggesting these compounds to react directly with bacterial DNA. Further, the reaction of these halodinitrobenzenes with methionine, at physiological pH, resulting in the formation of 1-S-methyldinitrobenzene showed that these compounds have the ability to attack DNA directly through nucleophilic substitution of the halogen atom and the role of the bacterial nitroreductases for production of mutagenic lesions was not considered. It was, further, proposed that these compounds interact with DNA through SNAr mechanism instead of SN2 cited in literature.

Alkylating Agents↗
PubMed1997

Oral expulsion of Taenia saginata.

We report a 25-year-old woman who presented with abdominal pain, vomiting and fever, and had an epigastric lump on examination. At laparotomy she was diagnosed to have acute segmental jejunitis. Three days postoperative, she vomited a 2-meter-long tapeworm (Taenia saginata), a rare route of expulsion.

Abdominal Pain↗
PubMed1997

Proliferating cell nuclear antigen immunostaining in breast carcinoma and its relationship to clinical and pathological variables.

Tumour proliferative activity of 74 breast lesions was assessed by determining mitotic index and immunostaining for proliferative cell nuclear antigen using Peroxidase antiperoxidase method. The indices were correlated with histomorphology and clinical stage of the disease. Positively stained nuclei and mitotic figures were counted per 1000 cells to calculate Proliferating Cell Nuclear Antigen (PCNA) and mitotic index respectively. Sixty four cases stained positive for PCNA. The index ranged between 0 to 98. PCNA index was significantly low in benign lesions as compared to malignant lesions (p < 0.0002). There was a linear correlation between the mitotic index and PCNA index. PCNA index also showed significant correlation with tumour size and histologic grade; however, it had no correlation with axillary lymph node status.

Breast Neoplasms↗
PubMed1996

Activation of tinidazole, an antiprotozoal drug to a mutagen by mammalian liver S9.

Tinidazole was found to display much higher mutagenic activity compared to metronidazole in Salmonella strain TA100 and YG1029. Under anaerobiosis, the specific activity of this nitroimidazole was enhanced, at least, by about 1.75-fold in TA100 and several fold in TA100NR relative to aerobic conditions. The mutagenicity in the latter strain with S9 mix became further increased by 2.5-fold under anaerobiosis, indicating the role of oxygen sensitive bacterial and mammalian S9 nitroreductases in the activation of the drug. The mutagenicity of the drug was slightly lowered in TA100/1,8-DNP6 (O-acetyltransferase deficient), YG1029 (O-acetyltransferase overexpressing) and TA100 in the presence of pentachlorophenol (PCP), an O-acetyltransferase inhibitor. These results rule out the possible involvement of N-acetoxyarylamine pathway in the metabolic activation of these nitroimidazoles.

Animals↗
PubMed1995

Genotoxicity of potential metabolites of nitroscanate--an antischistosomal drug.

The potential metabolites of nitroscanate(4-isothiocyanato-4'-nitrodiphenyl ether) such as 4-amino-4'-nitrodiphenyl ether (ANDE), 4-acetamido-4'-nitrodiphenyl ether (AcNDE), 4-acetamido-4'-nitrosodiphenyl ether (4-N = 0), 4-acetamido-4'-hydroxylaminodiphenyl ether (4-NHOH), 4-acetamido-4'-acetohydroxamicdiphenyl ether [4-N(OH)Ac], 4-acetamido-4'-formohydroxamicdiphenyl ether [4-N(OH)CHO] and 4-acetamido-4'-acetylaceto-hydroxamicdiphenyl ether [4-N(OAc)Ac] were synthesized and investigated in the standard Salmonella mutagenicity test using TA98, TA98NR, TA98/1,8-DNP6, TA100 and TA100NR as indicator strains, in the presence and absence of hepatic S9. The relative order of activity among nitro and its reduction products, 4-N = 0 and 4-NHOH in TA98 and TA100 was 4-N = 0 > 4-NHOH > AcNDE. In nitroreductase deficient strain TA98NR, AcNDE was inactive, but expressed a slight activity in TA100NR while 4-N = 0 and 4-NHOH showed a large increase in specific activity in both the strains. In O-acetyltransferase deficient strain TA98/1,8-DNP6, AcNDE was inactive, while 4-N = O and 4-NHOH showed a sharp fall in activity. The hydroxylamine derived products with an activity order 4-N(OAc)Ac > 4-N(OH)CHO > 4-N(OH)Ac in both TA98 and TA100, showed 3-6 times increase in the specific activity for the latter two compounds in the presence of S9 mix, which was inhibited in the presence of paraoxan, indicating N-deacylation as an important metabolic activation pathway. Except the 4-NO in TA100, the observed mutagenicity of nitroscante (NSC) was higher than those of potential metabolites and the nor-isothiocyanato derivative 4'-nitrodiphenyl ether, thereby showing that -NCS function has a potentiating effect on the mutagenicity of this drug.

Animals↗
PubMed1995

Mutagenicity of nitroscanate, an antischistosomal drug.

Nitroscanate (NSC) was found to be a direct acting mutagen in the Ames Salmonella tester strains TA100 and TA98 and this activity increased further in the presence of rat liver S9 mix. It was inactive in TA98NR and TA100NR, and weakly active in TA98/1,8-DNP6. A substantial fall in drug induced mutagenicity by pentachlorophenol, an inhibitor of acetyltransferase, in TA98, TA100 and YG1024 suggests the initial bioconversion of a nitro group to hydroxylamine and its further activation to the ultimate N-acetoxyarylamine. The refrigerated DMSO solution of the drug in the plate incorporation assay and freshly prepared solutions using the pre-incubation procedure indicated a fall in mutagenicity owing to the conversion of NSC to N,N'-bis-4-(p-nitrophenoxy)phenyl thiourea (NFPT). The drastic reduction in mutagenicity in the presence of 4-amino-4'-nitrodiphenyl ether (ANDE) and 4-aminodiphenyl ether (ADE) was also attributed to the conversion of NSC to the corresponding thiourea, a non-mutagen. The negligible mutagenicity of ANDE and its absence in ADE and 4-isothiocyanate diphenyl ether (ITDE) suggests that the mutagenicity of NSC is due to the nitro group, and the -NCS function is responsible for enhanced mutagenicity over nor-isothiocyanate 4-nitrodiphenyl ether (NDE).

Acetyltransferases↗
PubMed1995

Mutagenicity of nitrobenzyl derivatives: potential bioreductive anticancer agents.

Ortho-, meta- and para-nitrobenzyl bromides, alcohols, ethers and esters were synthesised and tested for their mutagenicity toward Salmonella typhimurium TA100, TA100NR (nitroreductase deficient) and TA98 in absence of S9 mix and in TA100 with S9 mix. Compounds of the ortho- and meta-series were non mutagenic with and without S9 mix. Except for the alcohol and ether, the compounds of the para-series were mutagenic in TA100 with activity sequence propionate > butyrate > benzoate > acetate > bromide and this specific activity was reduced considerably by S9 mix. The Ames Salmonella test system does not seem to be an appropriate model to evaluate mutagenicity of o-nitrobenzyls. However, further work is in progress to test all the compounds for mutagenicity in mammalian system.

Alcohols↗
PubMed1991

Mutagenicity of 4-nitrodiphenyl thioether-derived products and their potential metabolites.

4-Nitrodiphenyl thioether (4-NO2TE) and its various potential metabolites 4-nitroso- (4-NOTE), 4-hydroxylamino- (4-NHOHTE), 4-hydroxyacetylamino- [4-N(OH)ACTE], 4-acetoxy-acetylamino- [4-N(OAc)-ACTE], 4-amino- (4-ATE) and 4-acetamido- (4-AATE) were tested for their mutagenicity toward Salmonella typhimurium TA98 in the presence and absence of S9 activation system. 4-NO2TE, 4-NOTE, 4-NHOHTE and 4-N(OAc)ACTE were direct-acting mutagens with 4-NHOHTE having the highest activity. With S9 mix, the mutagenicity of 4NO2TE almost doubled and that of 4-NOTE and 4-N(OAc)ACTE decreased. In TA98NR, 4-NOTE induced higher mutations, while with 4-NHOHTE the number of revertants decreased. Both 4-NHOHTE and 4-N(OAc)ACTE showed decreased mutagenicity in TA98/1,8-DNP6. 4-ATE, 4-AATE and 4-N(OH)ACTE expressed mutagenicity only with S9 mix. 4-Nitrodiphenyl sulphoxide (4-NO2SO) and 4-nitrodiphenyl sulphone (4-NO2SO2), the sulphur-oxidised products of 4-NO2TE, were non-mutagenic as such and after addition of S9 activation system.

Animals↗