Biomedical subjects

V P Kamboj

Publications and source records attributed to V P Kamboj.

At least 19 recordsLinked to original sources

PubMed2002

Evaluation of interaction potential of certain concurrently administered drugs with pharmacological and pharmacokinetic profile of centchroman in rats.

Centchroman (Ormeloxifene) is a nonsteroidal, selective estrogen receptor modulator, oral contraceptive and anticancer agent, and is intended for long-term use by women. In view of its vast clinical application and the interaction of steroidal oral contraceptives with certain commonly used therapeutic agents, evaluation of interaction of certain concomitantly administered therapeutic agents (ibuprofen, rifampicin, diazepam, salbutamol, nifedipine, paracetamol, haloperidol, and tetracycline), in terms of both the postcoital contraceptive efficacy and pharmacokinetic profile, with centchroman was undertaken in female Sprague-Dawley rats. Among the representatives from each commonly used therapeutic category, interaction (pharmacokinetic) was observed with ibuprofen (60 mg/kg, twice daily), haloperidol (0.7 mg/kg, twice daily), and tetracycline (140 mg/kg, twice daily) coadministration on Days 1 through 5 postcoitum. Of these three therapeutic agents, only tetracycline interfered with the contraceptive efficacy of centchroman. It reduced the bioavailability of centchroman and its active metabolite by increasing their excretion through bile and feces. Increased metabolite excretion on tetracycline coadministration indicates the enterohepatic recirculation of the metabolite, not the parent drug. However, the effect of tetracycline was negated by the inclusion of lactic acid bacillus spores in the regimen.

Animals↗

PubMed2001

Interaction with anti-implantation and estrogen antagonistic activities of dl-ormeloxifene, a selective estrogen receptor modulator, by tetracycline in female Sprague-Dawley rats.

Among the 10 commonly used therapeutic agents investigated, concurrent oral administration of tetracycline (140 mg/kg) twice daily on Days 1-5 post-coitum (pc) interfered with the post-coital anti-implantation activity and almost completely abolished estrogen antagonistic activity of the single anti-implantation (1.5 mg/kg, orally) dose of dl-ormeloxifene administered on Day 1 pc, resulting in the occurrence of resorbed implantations in 50% of the females. However, no such interaction was evident when tetracycline was administered intramuscularly or when ormeloxifene was administered at twice its anti-implantation dose. There was no effect of ormeloxifene and/or tetracycline treatment on serum estradiol and progesterone levels, and all animals presented apparently normal corpora lutea. Ormeloxifene administered per se inhibited aminopyrine-N-demethylase (AD), glucose-6-phosphate dehydrogenase (G-6-PDH) and glutathione-S-transferase (GST) in the liver on the day of maximal endometrial receptivity, which was prevented by tetracycline co-administration. Aniline hydroxylase and AD were not detected in small intestine or uterus in vehicle control or any of the treatment groups. There was, however, no effect of ormeloxifene plus tetracycline treatment on serum total alkaline phosphatase activity. Findings suggest that interference with anti-implantation action of ormeloxifene by tetracycline might be due primarily to the almost complete abolition of its estrogen antagonistic activity at the uterine level, effected by decreased bioavailability of ormeloxifene and/or its active metabolite(s) by altered enterohepatic recirculation because of the effect on gut microflora. This might alternatively be related to an increased rate of its metabolism and elimination from the system via prevention of ormeloxifene-induced inhibition of hepatic AD, G-6-PDH, and GST, which, by effecting a decreased rate of metabolism, might be responsible for prolonged (approximately 120 h) duration of estrogen antagonistic/anti-implantation action of ormeloxifene in this species.

Animals↗

PubMed2001

A multicentric study with arteether in patients of uncomplicated falciparum malaria.

Two hundred and sixty seven patients of uncomplicated P. falciparum malaria completed study in a multicentric phase III clinical trial of Arteether. Arteether was given intramuscularly in a dose of 150 mg daily for three consecutive days. Each patient was followed upto 28 days of alpha, beta arteether therapy. The cure rate was 97% with fever clearance time between 1-7 days (24-168 hours) and parasite clearance time between 1-3 days (24-72 hours). Parasite reappearance rate was found to be 3% and reported at only three of the centres. Following the treatment no adverse effect was observed on haematological, biochemical and vital clinical parameters.

Adolescent↗

PubMed1999

Binding of centchroman with human serum as determined by charcoal adsorption method.

Protein binding of drugs is an important factor influencing both pharmacokinetic and pharmacodynamic parameters. Thus, knowing the extent of protein binding of drugs is crucial. Centchroman is a non-steroidal once a week oral contraceptive. It has been reported to be useful for the treatment of breast cancer and osteoporosis. Ample data has been generated on pharmacokinetics of centchroman in animals and humans. The extent of protein binding of centchroman has not been established so far. Non-specific adsorption of the drug limits the use of conventional methods like ultrafiltration and equilibrium dialysis. A method of charcoal adsorption as reported by Yuan et al. (method I) was used after modification (method II) to determine its binding to human serum. The extent of protein binding (%) is estimated from decline of percent drug remaining in the supernatant after adding the charcoal. Study was carried out at 1- and 10-microg/ml concentrations in drug free human serum samples and an HPLC assay was used to determine concentration-time data. The percentage of centchroman remaining in serum versus time data was analysed using non-linear fitting programs on WinNonlin software. Method II was found to give higher estimates of protein binding than the former method by preventing the dilution effect. Using this method, the extent of protein binding of centchroman was found to be 101.83+/-1.28 and 94.87+/-3.59% at 1 and 10 microg/ml, respectively. However, it was approximately 90% in the individual serum samples showing intersubject variability in protein binding of centchroman.

Adsorption↗

PubMed1997

Bioactivity of marine organisms: Part VIII--Screening of some marine flora of western coast of India.

Methanolic extracts of 31 botanically identified species of marine flora, collected from Gujarat Coast, have been screened for a wide range of biological activities. Of these, 3 extracts showed anti-implantation, 2 had antiviral, 2 showed hypotensive, 1 had anti-inflammatory while 12 extracts showed diuretic activities. The antiviral activity; against EMCV, was confirmed in one alga. The active principles and results of these studies are reported.

Animals↗

PubMed1996

Inhibition of progesterone-induced development of giant mitochondria in uterine glandular epithelial cells by an antiestrogen in rat.

Effect of antiestrogen ormeloxifene on progesterone-induced development of giant mitochondria in uterine glandular epithelial cells in ovariectomized adult Sprague-Dawley rats was investigated. Antiestrogen tamoxifen and antiprogestin onapristone were used for comparison. Well-formed giant mitochondria were observed in uterine glandular epithelial cells in rats treated with progesterone (20 mg/kg, subcutaneous [SC] per se for three consecutive days. In rats primed with estradiol-17 beta (0.5 micrograms/day, s.c.) on days-2 and -1 before progesterone treatment, there was, in addition, a marked increase and distension of smooth endoplasmic reticulum (SER) and Golgi complex, in comparison to extensive rough endoplasmic reticulum (RER) and polyribosomes in progesterone per se treated rats. Cytological picture in rats receiving single (1.25 mg/kg, day 1, p.o.) or multiple (0.25 mg/kg, days 1-3, p.o.) anti-implantation doses of ormeloxifene showed marked reduction in glandular epithelial cell height, luminal surface microvilli, RER, polyribosomes and cytoplasm:nucleus ratio, straightening of intercellular membranes, and interdigitation of basement membrane. Mitochondria were of normal size and nuclei were heterochromatic. Inhibition in the case of tamoxifen (0.1 mg/kg, days 1-3, p.o.) appeared partial and rare giant mitochondria with degenerating cristae and outer membranes were apparent. Onapristone (10 mg/kg, day 1, s.c.), in addition to inhibiting development of giant mitochondria, caused extensive vacuolization and distension of intercellular membranes in glandular epithelial cells.

Animals↗

PubMed1996

Uterine estradiol and progesterone receptor concentration, activities of certain antioxidant enzymes and dehydrogenases and histoarchitecture in relation to time of secretion of nidatory estrogen and high endometrial sensitivity in rat.

Alterations in uterine nuclear and cytosolic estradiol (ER) and progesterone (PR) receptor concentration, activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glucose-6-phosphate dehydrogenase (G-6-PDH) and lactate dehydrogenase (LDH), surface and transmission electron microscopy and histology in relation to the time of secretion of nidatory estrogen and the onset of endometrial sensitivity in the rat were investigated. A significant increase in plasma estradiol (E2) concentration in control rats was observed at 22.00 h on day 4 post-coitum, whereas progesterone (P) concentration increased at 17.00 h on day 4 and was maintained until 17.00 h on day 5. The period of high endometrial sensitivity (10.00 h on day 5) was characterized by elevated uterine cytosolic ER and nuclear and cytosolic PR concentration and POD activity, low columnar luminal epithelium with undulating surface and intercellular membranes, covered with short microvilli and pinopods, and containing numerous electron-transparent apical vesicles, mitochondria, polyribosomes, rough (RER) and smooth (SER) endoplasmic reticulum, well developed Golgi, few lysosomes and lipid droplets and loose edematous antimesometrial stroma. Inhibition in endometrial sensitivity by post-coital centchroman was associated with a marked depletion in uterine cytosolic ER and an increase in nuclear ER concentration, a decrease in POD and G-6-PDH activities, compact fibroblastic stroma, an increase in luminal epithelial cell height with decreased RER, SER, polyribosomes, Golgi, straightening of intercellular membranes, reduced surface undulations and absence of pinopods. Electron-transparent vesicles appeared flattened and clumped in the apical portion of cells, tight junctions were more prominent and lipid droplets were translucent. Nuclear and cytosolic PR and the pattern of secretion or plasma E2 and P remained unaffected. CAT, SOD and LDH activities, although high throughout pre-implantation, did not vary in relation to the secretion of nidatory estrogen, endometrial sensitivity or centchroman treatment.

Analysis of Variance↗

PubMed1996

Characterization of centchroman binding protein in plasma of rhesus monkey (Macaca mulatta).

Centchroman, a nonsteroidal antifertility agent was studied for its binding to monkey (Macaca mulatta) plasma proteins using charcoal adsorption and electrophoretic techniques. 14C-centchroman showed a low affinity binding and did not compete for 3H-cortisol or 3H-DHT binding sites in plasma. 14C-centchroman binding protein was heat stable in nature and showed the electrophoretic pattern similar to that of albumin (Rf 0.70). Thus centchroman binds to albumin in monkey plasma which can be suggested as carrier protein for this contraceptive agent.

Animals↗

PubMed1996

Correlation of pinopod development on uterine luminal epithelial surface with hormonal events and endometrial sensitivity in rat.

Intrinsic role of preovulatory and nidatory estrogen and progesterone and presence of viable blastocysts in utero in pinopod development on the uterine luminal epithelial surface and correlation between time of their development and onset of endometrial sensitivity were investigated. In adult rats, pinopods were observed on the entire epithelium even before secretion of nidatory estrogen, i.e. at 14.00 h on day 4 post-coitum (p.c.). Apparently, their number increased, more so on the antimesometrial than the mesometrial side, at 10.00 h on day 5, but were fewer and mostly collapsed at 10.00 h on day 6. Pinopods on day 4 were located within epithelial depressions and foldings, but protruded from the surface on days 5 and 6. Normal pinopods were also present on day 8 p.c. in rats under delayed implantation, but an implantation-inducing dose of estradiol-17 beta administered about 18 h earlier caused their collapse like that on day 6 in intact rats. Development and appearance of pinopods in intact or delayed rats was unaffected when native preimplantation embryos were prevented from entering the uterus. Normal pinopods were seen in immature rats receiving progesterone for at least 3 days or cyproterone acetate for 4 days, but not after estradiol alone. In animals receiving progesterone or priming/sensitizing estradiol in addition to progesterone, the decidual response was suboptimal, irrespective of the presence of pinopods on the day of stimulation. In animals in which a condition mimicking preimplantation had been produced by suitable hormone supplementation, optimal endometrial sensitivity and decidual response were elicited, even though most pinopods appeared collapsed, resembling those on day 6 in intact rats and about 18 h after estradiol in implantation-delayed rats. Findings confirm that pinopod development on uterine luminal epithelium was dependent on progesterone alone and demonstrate that: (i) preovulatory (priming) or nidatory (endometrial sensitizing) estrogen or viable blastocysts in utero have no role in their development. Nidatory estrogen, instead, appears to limit pinopod development by causing their collapse; (ii) pinopod development/presence on the endometrial surface might indicate the uterus coming into a period of sensitivity rather than actually being in it and might thus serve as a useful marker of "transfer window" rather than "implantation window"; (iii) in the rat, pinopod development might serve as an alternate assay for evaluation of progestational activity of newer test agents.

Animals↗

PubMed1996

Isolation and culture of hamster ectoplacental cone trophoblasts: an in vitro study on the cell types and their growth pattern.

The method of isolation of trophoblast cell types from ectoplacental cone of hamster embryo of day 8 post coitum (plug day as day 1) and examination of their growth pattern in vitro is presented in this study. Based on their size, three types of trophoblast cells were identified. (1) the smaller cells having clear cytoplasm formed the major portion (70% to 80%) of the total cell population (2) moderately bigger cells having mono or binucleated appearance and containing minute granules in the nuclear region formed 5% to 10% and (3) extra large and multinucleated cells shared 10% to 20% of the total cell number. While the smaller and slightly bigger cells showed moderate growth the larger ones had extensive growth and were seen to acquire different shapes on extending the duration of culture, such as fusiform, dumb-bell, polygonal, rectangular or flowery. The extremities of the cytoplasmic growth of these cells were seen to be thickened at one end giving the impression of a pad-like structure. The significance of these adaptations are not known at present.

Animals↗

PubMed1996

Determination of proteins secreted by growing rat decidual cells in vitro.

Proteins secreted by rat decidual cells while growing in culture medium were monitored on gel electrophoresis. It was done by assuming that outgrowing cells in vitro mimic differentiated endometrial stromal tissue in vivo following attachment of embryo. The decidual cells were obtained from implantation swellings of day 10 pregnant rats, maintained in serum free medium and the cell dependent protein profile was analysed after 48 hr on single dimensional polyacrylamide gel electrophoresis (SDS-PAGE). The proteins identified were in molecular weight range of 29, 43 and 66 kDa respectively. The result indicated involvement of the differentiated stromal cells in secreting these low molecular weight proteins.

Animals↗

PubMed1995

Surface morphology of hamster (Mesocricetus auratus) decidual cells in vitro.

Cell surface morphology of hamster decidual cells isolated from day 8 implantation swellings was studied, using both phase-contrast and scanning electron microscopy. Two kinds of cells, fibroblastic and epithelioid, were identified in cultures examined by phase-contrast microscopy. Fibroblastic cells were spindle-shaped, having pointed or blunt terminals on one end and bifid or webbed projections at the other end. Epithelioid cells, on the other hand, were flat and discoid, having a distinctively ruffled plasma membrane. Further, the plasma membrane of epithelioid cells formed rope-like or flange-like processes. The significance of such adaptations is discussed.

Animals↗

PubMed1995

Time-related effects of a triphenylethylene antiestrogen on estrogen-induced changes in uterine weight, estrogen receptors, and endometrial sensitivity in rats.

Time-related estrogen antagonistic action of a single oral contraceptive (1.25 mg/kg) dose of the triphenylethylene antiestrogen centchroman was determined in ovariectomized immature rats. Tamoxifen and nafoxidine were used for comparison. A single oral administration of centchroman followed by three doses of estradiol-17 beta (1 microgram/d, s.c.) caused significant dose-dependent inhibition in estradiol-17 beta-induced increase in uterine weight and nuclear and cytosolic estrogen receptors. But the inhibition at antiimplantation dose was evident only if estradiol-17 beta treatment was initiated not later than 48 h post-antiestrogen. Alternatively, when antiestrogen treatment was followed by a single dose of estradiol-17 beta between days 2-7, a synergistic action, typical of antiestrogens possessing weak estrogen agonistic activity, was observed. In immature rats in which a condition mimicking preimplantation was produced by estradiol-17 beta (0.5 microgram/d, s.c.) priming on days -2 and -1, followed by progesterone (1 mg/d, s.c.) and an endometrial sensitizing dose (0.5 microgram/d, s.c.) of estradiol-17 beta at 1600 h on day 4, anti-implantation dose of centchroman administered on day 1, too, failed to inhibit uterine weight gain induced by sensitizing dose of estradiol-17 beta, but caused marked inhibition in endometrial sensitivity to a deciduogenic stimulus and decidualization and weight gain of traumatized uterine horn 96 h post-traumatization over non-traumatized horn was only about 150% (725% in controls). Inhibition in endometrial sensitivity and decidualization was evident when the interval between antiestrogen treatment and sensitizing estradiol was < 126 h. Pinopods were present on endometrial surface on day 5 whether or not priming and/or sensitizing doses of estradiol were administered, but decidual response was mild if either of these doses of estradiol-17 beta was deferred. Findings suggest that: (a) duration of antiestrogenic action of single anti-implantation dose of centchroman in rat was about 126 h, which in ovariectomized immature rats was evident only when a condition mimicking preimplantation was produced and the antiestrogenic response was based on inhibition in estradiol-induced endometrial sensitivity and not uterine weight gain; (b) priming as well as sensitizing estrogen were essential to get optimal decidual responses; (c) appearance of pinopods on endometrial surface may not be related to endometrial sensitivity; and (d) tamoxifen and nafoxidine appear slightly longer acting with duration of antiestrogenic action of approximately 150 h.

Administration, Oral↗

PubMed1995

Ultrastructure of cellular components of human trophoblasts during early pregnancy.

Two cell types, the cyto- and syncytio-trophoblasts, were identified in human chorionic villi of 6-10 weeks' gestation. The intracellular organization of these cells was examined. Ultrathin sections of small pieces of chorionic villi revealed the presence of a multinucleate syncytiotrophoblastic layer, whose surface was covered with microvilli. The cytotrophoblasts, however, had a single large nucleus with a prominent nucleolus. An interesting feature of the basement membrane of these cells was the presence of aggregates of dark granules in samples of the earlier gestational age (6-8 weeks) and granular bodies having a dense outer ring and a translucent inner ring with a lucid central area in samples of 8-10 weeks' gestation. Both types of granules are mineralized and are assumed to perform a buffering role for maintaining the neutrality of the layer.

Cell Nucleus↗

PubMed1995

Post-coital contraceptive efficacy of the seeds of Nigella sativa in rats.

Hexane extract of the seeds of Nigella sativa L. prevented pregnancy in Sprague-Dawley rats treated orally at 2 g/kg daily dose on days 1-10 post-coitum. Significant antifertility activity was also observed in its column fractions and subfractions. At contraceptive dose, the active hexane extract exhibited only mild uterotrophic activity comparable almost to 0.002 mg/kg dose of 17 varies; is directly proportional to-Ethinylestradiol, but was devoid of any estrogenicity in the immature rat bioassay.

Animals↗

PubMed1994

Uterine estradiol and progesterone receptor concentration in relation to circulating hormone levels and histoarchitecture during high endometrial sensitivity and induced decidualization in guinea pigs.

Alterations in nuclear and cytosolic estradiol (ER) and progesterone (PR) receptor concentration in the antimesometrial (AM) and mesometrial (M) segments of the uterus in relation to circulating hormone levels, histology and surface topography during the period of high endometrial sensitivity and development of trauma-induced decidualization in cyclic guinea pigs were investigated. The period of high endometrial sensitivity (i.e. day 5 of the estrous cycle) was characterized by elevated plasma estradiol and progesterone and their receptors in the nuclear and cytosolic fractions of the uterus. There was, however, no difference in the concentration of these receptors or the surface ultrastructure in the AM and M segments. Unilateral traumatization by scissor cut along the AM length of the uterus on day 5 of the estrous cycle induced decidual cell reaction resulting in a marked increase in weight of the decidualized (traumatized) uterine horn with advancing decidualization to reach maximum levels (926% of the contralateral nontraumatized uterine horn) 7 days after traumatization. This was associated with decidual transformation and a marked increase in nuclear and cytosolic ER and PR concentration in the AM segment of the traumatized uterine horn. An increase in receptor concentration in the M segment of the traumatized uterine horn or the AM segment of the nontraumatized uterine horn was transitory and of a low order. Receptor concentration in the M segment of the nontraumatized uterine horn remained low throughout days 8-12 of the cycle. Findings indicate a possible role of both estradiol and progesterone in induction of endometrial sensitivity and development and maintenance of decidua in the guinea pig.

Animals↗

PubMed1994

Effect of a new anti-oestrogen and anti-implantation agent, CDRI-85/287, on tubal transport, development and viability of rat embryos.

The effect of CDRI-85/287, a pure nonsteroidal anti-oestrogen, on the rate of tubal transport and development and viability of embryos in rats was investigated. Single postcoital oral administration of an anti-implantation dose (2.5 mg kg-1) resulted in a mild acceleration in the passage of embryos through the oviduct; however, their rates of recovery, cleavage, blastocyst formation and zona shedding remained unaffected. Morphologically normal embryos were recovered from the genital tract up to Day 12 post coitum. Embryos recovered from CDRI-85/287-treated rats on Days 4 and 8 post coitum developed to normal term fetuses when transferred to uteri of untreated females. The compound therefore did not seem to have any deleterious direct effect on development or viability of rat embryos.

Animals↗

PubMed1994

Duration of anti-implantation action of the triphenylethylene anti-oestrogen centchroman in adult female rats.

The duration of the anti-implantation action of a single oral post-coital dose (1.25 mg kg-1) of a triphenylethylene anti-oestrogen, centchroman, was determined in adult rats. The effects of centchroman were compared with those of tamoxifen. In rats undergoing delay, centchroman administered orally on day 7 post-coitum prevented the induction of implantation of delayed blastocysts by an implantation inducing dose (1 micrograms per rat, s.c.) of oestrone which was administered earlier than 120 h after centchroman treatment. In tamoxifen (0.2 mg kg-1, orally) pretreated rats, oestrone administered at 144 h or later induced implantation. In cyclic rats treated with centchroman at intervals of 168 h and mated with males of proven fertility, implantation was prevented only when the interval between centchroman treatment and nidatory oestrogen secretion was less than 120 h. None of the females conceived when treated regularly at intervals of 120 h during exposure to fertile males. Discontinuation of treatment resulted in the occurrence of normal implantations in rats that mated 48 h or later after the last dose of centchroman, since in these animals the interval between anti-oestrogen treatment and nidatory oestrogen secretion was greater than 120 h. These findings suggest that the duration of the anti-implantation action of a single oral antifertility dose of centchroman in rats is about 120 h. Recovery of normal blastocysts from rats treated continuously with this dose of centchroman at these intervals suggests lack of significant effect on follicular maturation, ovulation, fertilization, preimplantation development or mating behaviour.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗