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Biomedical subjects

K Shanker

Publications and source records attributed to K Shanker.

At least 37 records · Page 2Linked to original sources
PubMed1996

Novel appearance of placental nuclear monoamine oxidase: biochemical and histochemical evidence for hyperserotonomic state in preeclampsia-eclampsia.

OBJECTIVE: The aim of this study was to explore the relevance of placental monoamine oxidase at the subcellular level in the etiology of the hyperserotonomic state in preeclampsia-eclampsia. STUDY DESIGN: The study was conducted on placentas from 20 normal pregnant women and 25 women with varied severity of preeclampsia-eclampsia. Placental serotonin and subcellular monoamine oxidase activity were determined. Histochemical localization of monoamine oxidase was done in placental sections and cell isolates. RESULTS: Placental serotonin increases with severity (rsystolic 0.84, rdiastolic 0.83) and monoamine oxidase decreases (rsystolic 0.86, rdiastolic 0.79). Placental monoamine oxidase showed marked changes in preeclampsia-eclampsia. Histochemical localization of monoamine oxidase showed diffused low activity evenly throughout the cytoplasm and nucleus of the syncytiotrophoblastic cells in preeclampsia-eclampsia; in contrast, normal placenta showed high activity in the cytoplasm without any activity in the nucleus of syncytiotrophoblastic cells. Detection of monoamine oxidase activity in nuclei of the placenta in preeclampsia-eclampsia is a novel finding. Monoamine oxidase activity at the subcellular level further strengthens this observation. A severity-dependent decrease was present in the nuclei of placentas with preeclampsia-eclampsia. The use of specific substrates and inhibitors revealed the presence of monoamine oxidase in mitochondria and nucleus. CONCLUSION: The study delineates an impaired catabolism of placental serotonin in preeclampsia-eclampsia. The novel appearance of monoamine oxidase in nuclei in proximity to its normal site and low activity resulting in a hyperserotonomic state may lead to preeclampsia-eclampsia.

Adult↗
PubMed1996

Study of mercury-selenium (Hg-Se) interactions and their impact on Hg uptake by the radish (Raphanus sativus) plant.

Pot culture experiments were conducted to study the effects of selenite and selenate treatment (0.5-6.0 microg/ml) on the uptake and translocation of root-absorbed mercury (Hg) in radish plants irrigated with 2 and 5 microg/ml Hg in sand and soil culture. Statistically significant reductions in mercury uptake with increasing concentrations of selenium (Se) were observed. Both forms of selenium (selenite and selenate) were equally effective in reducing the mercury burden of the plant. The observed reduction in plant uptake of mercury is explained by the formation of an HgSe insoluble complex in the soil-root environment. No significant difference (P > 0.05) in dry matter yields with the various selenium treatments was found, suggesting that no selenium toxicity or salt injury occurred in the plants.

Drug Interactions↗
PubMed1996

Status of free radicals and their scavenging enzymes in pregnancy induced hypertension (PIH).

The levels of lipid peroxidation (malonaldialdehyde), one of the consequence of free radical damage, and the antioxidant enzymes superoxide dismutase and catalase were estimated in the blood samples of fourteen normal and thirteen pregnancy induced hypertensive patients. A marked increase in malonaldialdehyde (p < 0.001) with concomitant decrease in superoxide dismutase (p < 0.001), catalase (p < 0.001) activities were observed in PIH as compared to normal pregnancy, thereby indicating the involvement of free radicals in PIH.

Adult↗
PubMed1996

A study of free radicals and scavenging enzyme in tonsillitis.

The present study is a comparison of malonaldialdehyde (MDA) level and superoxide dismutase (SOD) activity between controls and in tonsillitis patients of different degree before (pre) and after (post) surgery (tonsillectomy). The SOD activity increases in pretonsillectomy cases according to severity of disease and there is a rise in MDA level whereas after tonsillectomy although the increase in SOD is marginal but MDA declines sharply as compared to pretonsillectomy patients indicating that the SOD exerts its protective effect after surgery.

Free Radicals↗
PubMed1996

Synthesis of some new 2-methyl-4-(substituted benzylidene)1-phenyl-1,2,4 triazolo (3,4,-b) 1,4,5 thiadiazole as potential AChE inhibitory agents.

4-(1-aminophenyl)-1,2,4-triazolo[3,4,-b]1,3,4-thiadiozole (2) was prepared by treatment of 4-(1-aminophenyl)-5-mercapto-4-amino-1,2,4-S-triazole with carbondisulfide and KOH in methanol. This on further reaction with different 2-methyl-4-(substituted benzylidene)-oxazolin-5-ones gave 2-methyl-4-(substituted benzylidene)-1-phenyl-1,2,4[triazolo[3,4,-b]1,3,4-thiadiozoles. The compounds were screened for AChE inhibitory activity.

Animals↗
PubMed1995

Synthesis and pharmacological evaluation of 1,2,4-triazine and its congeners.

3-[Mercapto]-n-propanoxy/methyl-ethanoxy branched chain in 5,6-Diphenyl- 1,2,4-triazine were condensed with O-phenylene diamine or O- aminophenol or o-aminothiophenol. The carboxylic groups of the synthesized compounds were cyclised to yield imidazoles, oxazoles and thiazoles. They were screened for their anti-inflammatory response in albino rats against carrageenin induced paw oedema. The active compounds were also evaluated for their ED50 value in albino rats and analgesic activity in albino mice. The compounds exhibited significant anti-inflammatory activity also showed marked protection against aconitine induced writhing response. The potent compounds showed high LD50 values.

Animals↗
PubMed1995

Novel pyrimidinediones and thiazolidinones as anti depressants.

2-Mercapto-5-[4'-methoxy phenyl thiourea]-1,3,4-thiadiazole (2a-c) prepared by the condensation of 2-amino-5-mercapto-1,3,4-thiadiazole (1) with substituted phenyl isothiocyanates. Further on cyclisation with malonic acid in the presence of acetyl chloride gave the corresponding 2-mercapto-5-[3-(4-methoxy phenyl)-2-thioxo-2-5-dihydro-4, 6-pyrimidionoyl]-1,3,4-thiadiazole (3a-c) [sequence: see text]. This on further reaction with substituted aryl aldehydes in presence of zinc chloride gave 2-mercapto-5-[3-(4'-methoxy phenyl)-2'-thioxo-2',5'-dihydro-4',6' -pyrimidionoyl 5'-phenyl carboxaldehyde]-1,3,4- thiadiazole (4a-g) [sequence: see text]. The compounds were screened for antidepressant activity and compared with antidepressant (imipramine).

Animals↗
PubMed1995

Substituted quinazolinones and their anti-inflammatory activity.

6-Substituted-2-alkyl-3-(4-aminobenzene sulphonamido)quinazolin-4-(3H) ones (1a-b) were converted either to 2-methyl 3-[(N-aminoacylbenzoate)benzenes sulphonamido]quinazolin-4 (3H) ones (2a-c) or to 6-substituted-2-alkyl-3-(N-arylidene benzene sulphonamido)-quinazolin-4- (3H) ones (3a-h). 3 on reduction, yielded 6-substituted-2-alkyl-3-(N-arylmethyl sulphonamido)-quinazolin-4(3H)ones (4a-l). Reaction of 3a-h with thioglycolic acid afforded 2-alkyl-3-[4'-(5'-arylthiazolidin-3'-one)benzene sulphonamido]quinazolin-4(3H)ones (5a-h). All these compounds were evaluated for their anti-inflammatory activity against carrageenin induced rat's paw oedema. Active compounds were also evaluated for ulcerogenic liability and ALD50 values.

Animals↗
PubMed1994

Relevance of platelet serotonergic mechanisms in pregnancy induced hypertension.

Platelet functions are becoming the useful tool for delineating the etiology of pregnancy induced hypertension. Electronmicroscopic studies, efflux and content of 5-HT in platelets and platelet aggregation responses towards various aggregating agents have been measured in 25 normotensive pregnant subjects and 31 PIH subjects. Marked decrease changes have been noted in aggregation parameters with transformation from discoid to "spiny sphere" of platelets with long pseudopods along with prolonged time for spontaneous aggregation by platelets in PIH. Serotonin release from platelets was decreased and reserpine-induced release-reaction showed enhanced kinetics in PIH. Platelet serotonin content was raised and was inversely related to platelet count with severity of syndrome. Hence, a check and balance for platelet activation and aggregation in PIH might be crucial in the development of PIH.

Adolescent↗
PubMed1994

Synthesis of 1,3,4-thiadiazole-[3,2,-a]-s-triazine-5,7-dithione derivatives and their pharmacological evaluation.

2-Mercapto-6-phenyl-1,3,4-thiadiazole-(3,2-a)-s-triazine-5,7-dithione (1) was converted to 2-[3-carboxyl-2-methyl-1-mercapto]-6-phenyl-1,3,4-thiadiazole-(3,2-a)-s- triazine-5,6 dithione (2) and 2-thioethanoic acid-6-phenyl-1,3,4-thiadiazole-(3, 2-a)-s-triazine-5,7-dithione (4). This on reaction with o-phenylenediamine/ethylenediamine/o-aminophenol/o-aminothiophenol and polyphosphoric acid yielded compounds 3 (a-d) and 5 (a-d). The compounds 1,2,4,3 (a-d) and 5 (a-d) were evaluated for their anti-inflammatory activity against carrageenan induced paw oedema. The compounds found potent were further tested for their antiwrithmogenic activity in albino mice. Two compounds (2,3c) exhibited significant anti-inflammatory activity, also showed protection against aconitine induced writhing response, with high approximate LD50 values.

Animals↗
PubMed1994

Triazines as anti-inflammatory agents.

5,6-Diphenyl 1,2,4-triazine-3-thiol (III) was synthesized from alpha-diketone benzyl (II); II in turn was synthesized from benzoin (I). III on reaction with 1-chloro-2,3-epoxy propane yielded 3-[(oxiranyl methyl)thio]-5,6-diphenyl 1,2,4-triazine (IV). IV was converted to 3-[5,6-diphenyl-1,2,4-triazine-3-yl thio]-3-substituted propanols (V) on reaction with aryl amines. These compounds were screened for their anti-inflammatory activity in albino rats with carrageenin induced paw oedema. Two compounds, Ve and Vl, exhibited significant anti-inflammatory activity compared to the standard, phenylbutazone, with high ALD50 values.

Animals↗
PubMed1993

Antipyrine congeners as antidepressant agents.

1-(N-Antipyrinylglycyl)-3-arylideneamino)-2-thiobarbituric acids (III) were synthesized from 1-arylidene-4-(N-antipyrinyl glycyl)-3-thiosemicarbazones (II). Compounds II in turn were prepared from 4-amino antipyrine. Compounds III were finally converted into 1-(N-antipyrinylglycyl)-3-[(3'-chloro-4-aryl)azitidinyl]-2-t hiobarbituric acids (IV). 4-Aminoantipyrine was also treated with different N-protected amino acids in the presence of N,N'-dicyclohexylcarbodiimide to yield N-(antipyrinylcarbamoyl) substituted alkyl benzamides (V); their debenzoylation yielded 2-(amino-N-antipyrinyl) substituted acetamides (VI). The compounds were screened for their antidepressant activity. Compounds IIId, Va and Vb exhibited activity better than imipramine with less toxicity (ALD50 > 1000 mg/kg).

Amphetamine↗
PubMed1993

Anti-inflammatory and analgesic activity of indolyl quinazolones and their congeners.

6,8-Disubstituted-2-methyl-3-[2-substituted-indol-3-yl-methyl(ene)imino] -quinazoline-4(3H)-ones (III), 6,8-disbustituted-2-methyl-3-[2-substituted-indol-3-yl methyl amino]-quinazoline-4(3H)-ones (IV), 6,8-disubstituted-2-methyl-2-[5-(2-substituted-indol-3-yl)-thiazolidine- 3- one]quinazoline-4(3H)-ones (V), propionic acid derivative of 6,8-disubstituted-2-methyl-3-[5-(2-substituted indol-3-yl)-thiazolidine-3-one]-quinazoline-4(3H)-ones (VI), 6,8-disubstituted-2-methyl-3-[5-(2-substituted-indol-3-yl)-2-substituted benzylidine-thiazolidine-3-one]-quinazoline 4(3H)-ones (VII), 6,8-disubstituted-2-methyl-3-[2-substituted-indol-3-yl-4- chloroazetidine-1-one]-quinazoline-4-(3H)-ones (VIII), and 6,8-disubstituted-2-methyl-3-[2-substituted-indol-3- yl-alpha-arylazo methylimino]-quinazoline-4(3H)-ones (IX) were synthesized and evaluated for their anti-inflammatory activity against carrageenin induced paw oedema. The compounds found potent were further tested for their anti-writhmogenic activity in albino mice. The compounds exhibiting significant anti-inflammatory activity also showed marked protection against aconitine induced writhing response. The low toxicity of the potent compounds was also reflected by their high approximate LD50 values.

Animals↗
PubMed1993

Thiazolidinone congeners as central nervous system active agents.

3-(Benzylidene amino)-2-imino-4-thiazolidinones (IIa-c) synthesized by cyclization of substituted thiosemicarbazones (Ia-c) were converted into 2-amino-3-(substituted benzylamino)-4-thiazolidinones (IIIa-c), 2-imino-3-(alpha-aryl azo benzylidene) amino-4-thiazolidinones (IVa-f) and 2-(2-amino-4-oxo-3-thiazolidinyl)-3-aryl-4-isothiazolidinones (VIa-c), IVa-f were finally converted into 5-(arylamino methyl)-2-imino-3-(alpha-aryl azobenzylidene)-amino-4-thiazolidinones (Va-l). These compounds III, V and VI were evaluated for their monoamine oxidase (MAO) inhibitory activity in vitro and various CNS activities in vivo. Some of the compounds exhibited promising CNS activity.

Amphetamine↗
PubMed1992

Factors influencing platelet serotonin uptake in essential hypertension.

In a study of the mechanism(s) of platelet serotonin uptake alteration in essential hypertension, a total of 90 blood samples were analysed for platelet count and platelet serotonin uptake. These included 20 blood samples each of hypertensives, controls before and after cross-incubation experiments and 10 samples of hypertensives after control of blood pressure. It was observed that serotonin uptake was markedly reduced in hypertensive platelets. Diminished serotonin uptake in essential hypertension correlated directly with diastolic and mean arterial blood pressure and inversely with plasma total cholesterol values. In cross-incubation experiments using control platelets and hypertensive plasma, there was a significant reduction in platelet serotonin uptake (303.06 +/- 86.28 cpm/10(8) vs. 204.26 +/- 66.45 cpm/10(8); P less than 0.001), whereas hypertensive platelets when incubated with control plasma, showed increased serotonin uptake (233.50 +/- 75.19 cpm/10(8) vs. 312.64 +/- 79.54 cpm/10(8); P less than 0.01). Upon control of blood pressure, the platelet serotonin uptake improved significantly (205.45 +/- 70.0 cpm/10(8) vs. 266.77 +/- 61.68 cpm/10(8); P less than 0.05-0.01). From these results, it appears that reduced platelet serotonin uptake in essential hypertension is a reversible phenomenon probably governed by the presence of plasma factor(s) and/or altered platelet-membrane function.

Adult↗
PubMed1992

Coumarin congeners as antidepressants.

3-Carboethyl coumarin (I) was converted to coumarin 3-acid hydrazide (II). This on reaction with appropriate aldehyde yielded 3-arylidino amino coumarin (III). Compound III on diazotisation and reaction with ferric chloride yielded the corresponding formazans viz. 3-substituted phenyl azoarylidino, amido coumarins (IVa1-a10) and oxadiazoles viz. 2-aryl-5-(3-coumarinyl)-1,3,4-oxadiazoles (Va1-a3), respectively. Simultaneously 3-carboethyl coumarin on hydrolysis gave 3-carboxy coumarin (VI) which on reaction with aryl amine in methylene chloride yielded 3-(N-aryl)amido coumarin (VIIa1-a3). The compounds were screened for their antidepressant activity against a tricyclic antidepressant (imipramine). Compounds IVa4, IVa5 and IVa9 exhibited activity better than imipramine with no toxicity (ALD50 greater than 1000 mg/kg) but IVa5 showed some side effects.

Amphetamine↗
PubMed1992

Synthesis and pharmacological evaluation of some phenothiazines as antidepressants.

10-Hydrazino acetyl phenothiazine (II) has been converted to N-10-acetyl amino phenothiazine-N-phenyl thiourea (III) which have been converted to 3-aryl-1-(10-phenothiazine acetyl amino)-2,3-dihydro-2-thioxo-4,6-(1H,5H) pyrimidinones (IV) on condensation with aryl amines and aryl aldehydes yielded 3-aryl-1-(10-Phenothiazine acetyl amino)-5-(substituted phenyl amino methyl)-2,3-dihydro-2-thioxo-4,6-(1H, 5H) pyrimidinediones (Va-k) and 3-aryl-1-(10-phenothiazine acetyl amino)-5-(substituted phenylidine)-2,3-dihydro-2-thioxo-4,6-(1H, 5H) pyrimidinediones (vl-o). The compounds were screened for their antidepressant activity against a tricyclic antidepressant (imipramine). Compounds Va, Vf, Vm and Vi exhibited activity better than imipramine with no toxicity (ALD50 greater than 1000 mg/kg) but Vi showed some side effects.

Amphetamine↗