Search PubMed⌕ Search

Biomedical subjects

A K Pal

Publications and source records attributed to A K Pal.

At least 55 records · Page 3Linked to original sources
PubMed1987

DNA damage by 5-nitro-2-furylacrylic acid, a nitrofuran derivative.

5-Nitro-2-furylacrylic acid (5-NFA) caused dose dependent inhibition of growth of Escherichia coli K-12 strain AB 2480 (uvr-, rec-), the 37% (D37) and 10% (D10) survival doses being 1.0 microgram/ml.h and 1.75 micrograms/ml.h, respectively. Although much higher doses of drug were required to achieve comparable inhibition of growth of E. coli strain 1157 (repair proficient), significant filamentation of these cells was produced by treatment with 1.0 microgram/ml 5-NFA for 4 hr. Ultraviolet absorption data and thermal chromatography through hydroxyapatite (HAP) column revealed that 5-NFA treatment of E. coli strain AB 2480 produced more than 80% of DNA reversibly bihelical due to the formation of interstrand cross-links and the initial part of the reaction obeyed a first order relation. 5-NFA also produced dose-dependent increase of prophage induction in E. coli strain GY 5027: envA, uvrB, ampA1, strA (lambda). The implications of the action of 5-NFA on DNA in relation to the induction of 'SOS' functions and carcinogenesis were discussed.

Acrylates↗
PubMed1987

99mTc-2,3-diaminopropionic acid complex as renal function agent: comparison of biological properties with 99mTc-DTPA and 131I-OIH.

The preparation, purification, biodistribution, blood disappearance kinetics and imaging characteristics of 99mTc-2,3-diamino propionic acid (99m-Tc-DAPA) is studied. The latter three studies were conducted on rabbits as the experimental animal and the data thus obtained were compared with 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) and 131I-orthoiodohippurate (131I-OIH) with a view to find a possible replacement of the latter radiopharmaceutical with a more convenient 99mTc based compound. Preliminary data indicates favourable results for 99mTc-2,3-diamino propionic acid which warrants further investigation.

Animals↗
PubMed1986

Flowers of Hibiscus rosa-sinensis, a potential source of contragestative agent. III: Interceptive effect of benzene extract in mouse.

In mouse, oral administration of the benzene extract of Hibiscus rosa-sinensis flowers at a dose level of 1 gm/kg body weight/day from day 5-8 of gestation led to termination of pregnancy in about 92% of the animals. The effect was associated with a significant fall in peripheral level of progesterone and increase in uterine acid phosphatase activity, as measured on day 10. The ovary exhibited signs of luteolysis, and the corpus luteal delta 5-3 beta -hydroxysteroid dehydrogenase activity decreased markedly. The interceptive effect of the extract was prevented completely by exogenous progesterone (1 mg/mouse/day) or chorionic gonadotropin (1 I.U./mouse/day) and partially (62.5%) by exogenous prolactin (500 micrograms/mouse/day). In unilaterally pregnant mouse having trauma-induced deciduomata in the sterile horn, the extract caused resorption of the fetuses, and regression of the deciduomata accompanied by reduction in weight of the ovaries. Luteolysis, may be due to interference with the luteotropic influence, and a consequent fall in plasma level of progesterone have been suggested as the plausible cause of termination of pregnancy.

Abortifacient Agents↗
PubMed1986

Disruption of pregnancy in mouse by aristolic acid: I. Plausible explanation in relation to early pregnancy events.

Aristolic acid (AA), obtained from Aristolochia indica Linn, disrupted nidation in mice when administered on Day 1 of pregnancy. The implantation inhibiting effect of the compound was assessed with respect to certain parameters which are characteristics of early pregnancy, such as tubal transport of ova into the uterus, hyperpermeability of the endometrial capillaries, increase in uterine weight and total protein content, endometrial bed preparation and changes in uterine phosphatase enzymes during Days 4-6 of pregnancy. The compound did not affect tubal transport of eggs, but the uterine blue reaction, caused by extravasation of the dye, pontamine blue, at future implantation sites was inhibited significantly in treated mice. Histological picture of the uterus revealed AA-induced impairment of development (i.e. decidualization) and reconciled with decreases found in uterine weight and its total protein contents in treated animals. In control untreated mice, specific uterine alkaline phosphatase (ALP) activity increased significantly from Days 4 through 6 of pregnancy, but this was prevented in treated mice. On the other hand, specific uterine acid phosphatase (AP) activity was high on Day 5, while in treated mice uterine AP activity remained low during Days 4 and 5 and increased significantly thereafter. It was inferred that AA interferes with steroidal conditioning of the uterus and renders it hostile to ovum implantation.

Acid Phosphatase↗
PubMed1985

Flowers of Hibiscus rosa-sinensis, a potential source of contragestative agent: II. Possible mode of action with reference to anti-implantation effect of the benzene extract.

Benzene extractives of Hibiscus rosa-sinensis flowers, administered during day 1-4 of gestation, exerted anti-implantation effect without affecting the tubal transport of zygote. On day 4, normal number of blastocyst was present in the uterus but they did not implant. However, as studied by pontamine blue reaction, it was evident that hyper-permeability of the endometrial capillaries which is the earliest known response of a receptive endometrium to any kind of deciduogenic stimulus was inhibited by the extract. The magnitude of decidualization, as assessed by weight of the traumatized uterine horn and supported by the histological pictures of the uteri was significantly lower in comparison to that of the controls. Ovarian structure exhibited signs of luteolysis. Inadequate progestational development of the endometrium due to interference with the conditioning of the uterus with progesterone during prenidatory phase of pregnancy has been suggested as the plausible cause of the extract-induced implantation failure.

Animals↗
PubMed1984

Flowers of Hibiscus rosa-sinensis, a potential source of contragestative agent: I. effect of benzene extract on implantation of mouse.

In mouse, the benzene extract of Hibiscus rosa-senensis flowers was administered at four different dose levels (250-1000 mg/kg body weight/day) from day 1-4 postcoitus. Anti-implantation response and associated changes in the uterine chemical composition were studied. With an increase in the dosage of the extract, the percentage of implantation failure increased. At the dose level of 1 gm/kg body weight, the extract led to failure of implantation in 93% of the mice. The effect was accompanied by adversely altered uterine weight, its protein content and alkaline and acid phosphatase activity. In another experiment, influence of the extract on uterine uptake of progesterone was studied in bilaterally ovariectomized mice treated with or without estrogen. It exerted neither inhibitory nor stimulatory influence on uterine progesterone uptake in untreated castrated mice but the estrogen-induced increase in the uptake level was significantly inhibited by the extract. Failure of uterine bed preparation due to antiestrogenic potentiality of the extract has been discussed as the plausible cause of implantation failure.

Acid Phosphatase↗
PubMed1984

Chromosome analysis of Dalton's lymphoma adapted to the Swiss mouse: clonal evaluation and C-heterochromatin distribution.

Chromosome studies of Dalton's lymphoma, which was originally developed in the DBA/2 mouse and later adapted to a close inbred strain of the Swiss albino mouse, revealed only one rb-marker in all cells bearing a modal number (71). After several successive in vivo passages of the tumor, a new cell clone appeared with a different modal number (70) and two rb-markers. This new cell clone gradually outnumbered the stem cells and an apparent enhancement in tumorigenicity was noted. C-banding of the new cell clone revealed that one of the two telomeric heterochromatin-bearing chromosomes, originally present in the stem cells, had been involved in a Robertsonian fusion to form the additional marker chromosome. G-banded analysis indicated the noninvolvement of chromosome #15 in the fusion.

Animals↗
PubMed1984

Luteolytic influence of intrauterine dead embryos in the early pregnant rat.

The present investigation was an endeavour to study if annihilation of embryos in the uterus of the rat before the establishment of placental luteotropic functions has any influence on corpus luteal function, and, if there is any, whether it is local or systemic. The responsibility of pregnancy maintenance was imposed on a single ovary by performing unilateral ovariectomy after implantation (on Day 5 postcoitum). The implantation sites in one uterine horn, either ipsilateral or contralateral to the remaining ovary, were selectively destroyed by injecting 0.1 ml of sterile normal saline to that particular horn only, and the peripheral progesterone level and viability of the embryos in the untreated horn, which depended on the functions of the remaining ovary, were examined. Selective killing of embryos in the uterine horn of the ovariectomized side did not exert any influence on the fetal viability in the untreated horn ( nonovariectomized side) and the peripheral progesterone level also remained statistically unaffected. On the contrary, induction of fetal resorptions in the uterine horn of the intact side produced a significant fall in the peripheral level of progesterone and induced resorption of embryos of the ovariectomized side also. The latter could significantly be prevented by simultaneous administration of exogenous progesterone, indicating luteolysis as the major, if not sole, factor responsible for fetal resorption in the untreated horn. The luteolytic effect was attributed neither to saline itself, nor to the distension of the uterine horn caused by saline injection. Luteolytic factors from the dead embryo-bearing horn which act locally on the adjacent ovary only, are discussed.

Animals↗
PubMed1984

Appendix duplex.

Explore the source record for details and available documents.

Appendix↗
PubMed1983

DNA damage, prophage induction and mutation by furazolidone.

Ultraviolet absorption data and thermal chromatography through hydroxyapatite (HAP) column revealed that furazolidone treatment of Vibrio cholerae cells produced more than 80% of DNA reversibly bihelical due to the formation of interstrand cross-links and the reaction obeyed a first order relation. Sensitivities of the Escherichia coli strains to the lethal action of the drug were in the order: AB 2480(uvr- rec-) greater than AB 2463(rec-) greater than AB 1886(uvr-) greater than AB 1157(repair proficient) or AB 4401(wild type). Furazolidone was 'Rec test' positive, produced dose-dependent prophage induction in E. coli cells and also dose-dependent streptomycin-resistance forward mutation in V. cholerae cells. The quantitative aspect and also the mode of furazolidone action on DNA were discussed.

DNA Repair↗
PubMed1983

Modulation of luteinizing hormone receptors: effect of an inhibitor of prolactin secretion, p-coumaric acid.

Daily oral administration of p-coumaric acid (PCA) at a dose of 50 mg/kg body wt for 21 days to adult male mice caused a dramatic reduction in serum prolactin concentrations. A significant fall in testicular LH binding was also observed after PCA treatment. Complete recovery of testicular LH binding was obtained by daily administration of prolactin (500 micrograms/mouse) when given simultaneously from day 9 of PCA treatment. A lower daily dose of prolactin (250 micrograms) was found to be ineffective. Scatchard analysis of binding data suggested a decrease in the number of testicular LH binding sites after PCA treatment whereas the affinity constant was unchanged. These results provide direct evidence for an inhibitory effect of PCA on prolactin secretion and also provide additional evidence in favour of a role of prolactin in the modulation of LH receptors.

Animals↗