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Biomedical subjects

J Sengupta

Publications and source records attributed to J Sengupta.

At least 73 records · Page 4Linked to original sources
PubMed1989

Is there any delta 5-3 beta hydroxysteroid dehydrogenase activity in preimplantation embryo of rhesus monkey?

This is the first report on the histochemical assessment of delta 5-3 beta hydroxysteroid dehydrogenase activity in all the preimplantation embryonic stages in the rhesus monkey (Macaca mulatta). An apparent stage dependent increase in enzyme activity was obtained, however, distinctively a high degree of non-specificity in enzyme reaction was noted primarily in morulae and blastocysts. Such marked non-specificity in the histochemical enzyme reaction for delta 5-3 beta hydroxysteroid dehydrogenase activity was not found in mouse blastocysts. High amounts of endogenous steroids present within rhesus embryos, or the participation of non-specific dehydrogenases could account for the observed non-specificity. Furthermore, the present report documents the pattern and degree of association (r = 0.9; P less than 0.01) between developmental stage and gestational age of preimplantation rhesus embryos, and thus provides a normal in situ cell cleavage rate of preimplantation embryo in the rhesus monkey.

3-Hydroxysteroid Dehydrogenases↗
PubMed1988

Patterns of estrogen and progesterone receptors in rhesus monkey endometrium during secretory phase of normal menstrual cycle and preimplantation stages of gestation.

Using validated methods, estradiol receptor (ER) and progesterone receptor (PgR) levels have been estimated in endometria collected in secretory phase of normal menstrual cycle and preimplantation stages of gestation from rhesus monkeys (Macaca mulatta). Endometrial PgR in both cytoplasmic and nuclear compartments decreased significantly (P less than 0.001) from day 2 to day 6 post-ovulation in both groups, but in fertile cycle, absolute levels of nuclear PgR remained significantly higher (P less than 0.05) on days 4, 5 and 6 of gestation, ER concentrations, both total (P less than 0.02), as well as cytoplasmic (P less than 0.01) declined significantly in secretory phase of normal menstrual cycle while nuclear ER levels remained unchanged. In the preimplantation period, ER patterns remained unvarying on days 2-6 of gestation in both cytoplasmic and nuclear compartments; their levels in nuclear fraction were significantly higher from day 3 onwards while, total cytoplasmic ER concentrations were higher from day 4 of gestation compared with the values obtained for secretory phase tissues from normal ovulatory cycles. No changes were, however, detected in apparent equilibrium dissociation constants (Kd) for the sex steroid receptors in endometria obtained from fertile and non-fertile cycles. It has been suggested that in prenidatory stage rhesus monkey endometrium elevated concentrations of nuclear ER and PgR possibly indicate higher degree of nuclear occupancy required for endometrial differentiation permitting blastocyst implantation.

Animals↗
PubMed1988

Endometrial phosphatases, beta-glucuronidase and cathepsin D during menstrual cycle and pre-implantation stages of gestation in the rhesus monkey (Macaca mulatta).

beta-glucuronidase, cathepsin D, acid and alkaline phosphatases were studied in rhesus monkey endometrium during the menstrual cycle (day -6 to day +10) and pre-implantation stages (day +3 to day +6) of gestation, with day 0 considered as the day of ovulation. Acid hydrolases exhibited low levels in proliferative phase endometria followed by their gradual rise in the secretory phase of the menstrual cycle. Despite no shifts in the levels of serum progesterone and estradiol-17 beta, the pre-implantation period was, however, associated with distinct changes in enzyme profiles characterized by lower absolute levels (P less than 0.05) of acid phosphatase and beta-glucuronidase on days 3 to 6 of gestation, whereas cathepsin D activity declined significantly (P less than 0.05) on days 5 and 6. Alkaline phosphatase showed a characteristic rise during the pre-ovulatory period with a gradual lowering of its level in post-ovulatory phase endometria of a non-fertile cycle; in contrast, during early gestation, alkaline phosphatase activity showed a marked elevation (P less than 0.05) on days 5 and 6 of gestation. The significance of these findings is discussed.

Acid Phosphatase↗
PubMed1988

A comparative study of endometrial acid phosphatase activity in the mid-luteal phase of the menstrual cycle and in the peri-implantation stage in the rhesus monkey (Macaca mulatta).

Acid phosphatase activity in both total and subcellular fractions of endometrium of rhesus monkey on day 5 of gestation was significantly (P less than 0.01) lower than levels found in tissues collected from normally menstruating monkeys on day 5 after ovulation. This endometrial response to preimplantation embryo may be related to the menstrual withdrawal in a fertile cycle.

Acid Phosphatase↗
PubMed1985

Liposome-facilitated enhancement of in vitro immunity to human colon cancer.

Liposome-antigens, in the presence of dialyzable leukocyte extracts (DLE)(1), were tested for their ability to enhance in vitro blastogenic responses to colon tumor antigens. Liposomes made with 6:4:1 molar ratios of phosphatidylcholine, cholesterol, and phosphatidic acid and bearing human colon cancer cell antigens were shown to be immunogenic in vitro, producing specific blastogenic responses. Addition of nonimmune DLE (500 micrograms/5 X 10(5) lymphocytes) in the in vitro culture system enhanced the blastogenic response 3x over liposome-antigen alone (p less than 0.001). Immune DLE (immune to keyhole limpet hemocyanin (KLH) and tuberculin (PPD) antigens) were suppressive (p less than 0.05) in the same study. Blastogenic reactivity to KLH was also generated in nonimmune lymphocytes and enhanced by liposomes with DLE specific to KLH (p less than 0.01). Nonspecific DLE (e.g., to PPD) caused suppression of KLH-induced blastogenesis (p less than 0.05). These findings confirm and extend prior reports noting that DLEs contain both specific and nonspecific lymphocyte blastogenic factors and suggest the use of this liposome-adjuvant system for boosting tumor immune responses.

Adenocarcinoma↗
PubMed1984

Carbohydrate metabolism in 'delayed implanting' mouse blastocysts undergoing activation in utero and in vitro.

Delayed blastocysts were activated by injecting oestradiol-17 beta to delayed implanting mice or by exposure to culture medium lacking serum. Four enzymes of carbohydrate metabolism (phosphofructokinase, pyruvate kinase, lactate dehydrogenase, malate dehydrogenase) were studied at different time periods and specific time-dependent changes were found during activation. A characteristic feature was a marked decline by 6 h in the activities of phosphofructokinase and pyruvate kinase. Blastocyst activation in vitro and in utero showed similar trends in metabolic patterns during the 24-h period studied.

Animals↗
PubMed1984

Role of embryonic oestrogen in rabbit blastocyst development and metabolism.

Rabbit morulae were grown for 24 h in Ham's F12 medium supplemented with BSA. CI-628 citrate (1.5 micrograms/ml), a specific oestrogen antagonist, significantly inhibited the transformation of morulae to blastocysts. This inhibition was reversed with oestradiol-17 beta (1 micrograms/ml) but not oestradiol-17 alpha (1 micrograms/ml) added to the culture medium. The specific activities of phosphofructokinase, lactic dehydrogenase, malate dehydrogenase and alkaline phosphatase in blastocysts grown in vitro for 24 h in medium TC 199 + BSA showed significant elevation with blastocyst growth and expansion, while that of acid phosphatase revealed no change, and leucine aminopeptidase activity declined significantly. These changes were markedly inhibited by CI-628 citrate (2 micrograms/ml) and were reversed by oestradiol-17 beta (0.4 micrograms/ml) but not by oestradiol-17 alpha (0.4 micrograms/ml). Our findings suggest a role of oestrogen present in the rabbit morula and blastocyst in the triggering of embryonic differentiation and metabolic functions.

Alkaline Phosphatase↗
PubMed1984

In vitro expression of suppressogenic and enhancing activities in human colon cancer cells.

The presence of immunoregulatory factors in a human colon cancer cell line, LS174T, was exhibited in mitogenic and immunogenic assays. The simultaneous presence of stimulatory and suppressive factors in the spent media of LS174T colon cancer cells was shown. Opposing suppressive and stimulatory activities were extractable from viable tumor cells and found in 3 M KCl extracts fractionated by isoelectric focusing. Suppressogenic activity was demonstrated in concanavalin A and phytohemagglutinin mitogenesis in both human and murine lymphocytes; the blastogenesis of mixed lymphocyte culture reactions was suppressed, while responses of immune cells were not. Naive lymphocytes were stimulated or not affected by the same spent media. The factors appeared to require cell viability for optimal expression and were not species specific. These results further illustrate the complexity of tumor cell-host cell interactions and emphasize the need for in vitro assays to measure, characterize, and exploit the factors.

Adenocarcinoma↗
PubMed1983

Effect of an estrogen antagonist on development of blastocysts and implantation in the hamster.

CI 628 citrate, an estrogen antagonist, was given as a single intraluminal injection (5 micrograms) on day 3 to ovariectomized, progesterone-treated hamsters. This significantly reduced embryo cleavage rate, transformation of morula into blastocyst, and completely inhibited implantation. The effects of the drug could be reversed by estradiol-17B (1 microgram) but not estradiol-17 alpha (1 microgram) injected intraluminally with CI 628 citrate. Our finding suggests a role of estrogen present in hamster preimplantation embryo in the triggering of embryonic differentiation and implantation of the blastocyst.

Animals↗
PubMed1983

Steroid hormones and embryo development in ovariectomized hamsters.

Preimplantation embryo development was arrested at the premorula stage in hamsters ovariectomized on Day 1 of pregnancy. This effect was reversed when 500 micrograms progesterone were administered daily. Oestradiol-17 beta given alone had no significant effect on the cleavage rate or blastocyst formation, but a synergistic response was evident when a suboptimal (30 micrograms) dose of progesterone was given with 50 ng oestradiol-17 beta. Cholesterol and hydrocortisol had no effect on embryo development.

Animals↗
PubMed1983

Histochemical study of beta-glucuronidase in the rat uterus during implantation and pseudopregnancy.

On Day 5 of pregnancy and pseudopregnancy, beta-glucuronidase activity in pseudopregnant uteri and in the inter-implantation zones from pregnant animals was found mainly in stromal and glandular epithelial cells. The luminal epithelium also showed an intense enzyme-positive reaction, particularly in the apical regions of these cells. Blastocyst attachment was associated with marked depletion of beta-glucuronidase activity from epithelial cells lying adjacent to the blastocyst, suggesting a possible involvement of this lysosomal enzyme in the blastocyst-endometrium attachment reaction.

Animals↗
PubMed1983

Liposome uptake into human colon adenocarcinoma cells in monolayer, spinner, and trypsinized cultures.

The purpose of this study was to begin investigating the nature of liposome interactions with colon tumor cells. Thus, experiments were performed to study the uptake and incorporation of multilamellar and of reverse-phase evaporation liposomes of neutral charge into monolayers, suspended spinner cultures, and trypsinized cells of a human colon adenocarcinoma cell line, LS174T. The results showed that the same tumor cells cultured under each condition exhibited a distinct pattern of vesicle uptake as determined at 0, 15, 30, 60, and 120 min. In monolayer cultures of LS174T cells, the uptake of liposomes bearing [3H]actinomycin D in the lipid bilayers was linear throughout the incubation period. In contrast, in trypsinized and spinner suspension cultures, uptake of liposomes was biphasic. There was a proportional uptake of both liposome (labeled with [3H]phosphatidylcholine or [14C]cholesterol) and of actinomycin D (trace labeled with 3H) into the cells under all culture conditions, indicating quantitative delivery of the drug with the intact lipid vesicle. Although the amount of actinomycin D presented to tumor cells by the two liposomes was equivalent, reverse-phase evaporation liposomes were more effective than multilamellar vesicles in inhibiting uridine uptake. In the presence of excess liposomes (10 times the uptake studies), saturation of the tumor cell surface occurred by 120 min. However, the liposomes remained accessible to enzymatic removal for 60 min. Liposome-saturated tumor cells remained refractory to further binding of liposomes for at least 2 hr. The results thus revealed that differences in cell uptake were due to the state of the target cells and not the liposome types, or their differential leakage of labels.

Adenocarcinoma↗
PubMed1982

In vitro inhibiton of trophoblast maturation and expansion of early rat blastocysts by an oestrogen antagonist.

Rat blastocyst development and expansion were studied in an in vitro culture system. Early blastocysts collected from rats on the morning of day 5 were shown to develop normally and underwent expansion when placed in bovine serum albumin supplemented culture medium for 12 h at 37 degrees C. Nafoxidine, an oestrogen antagonist, prevented embryo expansion when added to the culture medium, and it was found that if oestradiol-17 beta was added to this medium this inhibitory effect was removed and the embryos again expanded. Ethanol, used as a solvent for steroids, and cholesterol were added to the medium containing nafoxidine but the blastocysts remained unexpanded after 12 h in culture. These results suggest a need for oestrogen action during blastocyst expansion in vitro. Cultured rat blastocysts were subjected to histochemical study for acid phosphatase (ACPase) and leucylnaphthylamidase (LNAse). In unexpanded blastocysts ACPase was found to be low while LNAse activity was higher when compared with enzyme distribution patterns in expanded blastocysts.

Acid Phosphatase↗
PubMed1982

A study of carbohydrate metabolism in 'delayed' and 'activated' mouse blastocyst and uterus.

Several regulatory enzymes of carbohydrate metabolism were studied in blastocysts and uteri of mice in which implantation had been delayed and of oestrogen-activated mice, and compared with those of normal mice just before implantation on day 4 of pregnancy. A significant increase in the activities of phosphofructokinase and pyruvate kinase was observed but the level of lactate dehydrogenase declined in delayed blastocysts. Carbohydrate metabolism in the uterus remained essentially unchanged during the delay period. A study of uterine mitotic patterns showed a steady increase in stromal mitosis after administration of oestradiol to animals in which implantation had been delayed.

Animals↗
PubMed1982

A new approach for the immunogenic presentation of membrane-bound human colon tumor antigens.

Liposomes bearing human tumor membrane vesicles were effective immunogenic complexes for inducing antibodies in rabbits. Multilamellar liposomes (MLV) at 7:4:1 molar ratios of phosphatidylcholine, cholesterol and phosphatidic acid were prepared with sonicated membrane (MN) isolated from LS174T colon tumor cells. MLV liposomes prepared together with MN (i.e., MN-MLV antigens) or MN added to preformed MLV (i.e., MN+MLV antigens), and MN antigens alone were used as immunogens. Rabbits were immunized i.v. with 100 g protein of each antigen group. Boosters (i.v.) were at days 13 and 29. Binding assays were performed by indirect radioimmunoassay on viable tumor cell targets. The MN+MLV groups were distinguished by earlier reactivity and greater specificity to the colon tumor antigens.

Adenocarcinoma↗