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Biomedical subjects

P K Mehrotra

Publications and source records attributed to P K Mehrotra.

At least 37 records · Page 2Linked to original sources
PubMed1997

Study of pulmonary functions in swimmers of Lucknow city.

In this study, the pulmonary functions of young swimmers of K.D. Singh Babu Stadium, Lucknow were studied, 20 swimmers of the age group of 15-20 years were chosen along with 15 students as controls. The parameters taken into account were Forced Vital Capacity (FVC), Forced Expiratory Volume (FEV1) and Peak Expiratory Flow Rate (PEFR). Two sets of readings were recorded. One before the start and the other at the end of the practice season. These readings were compared to each other and also with the values of the controls. The results indicate that swimming has considerable effect on enhancing lung functions of an individual as FVC, FEV1, PEFR were significantly raised in swimmers after swimming session. Such results suggest that swimming may be induced in the exercise programme for rehabilitation of respiratory patients who have compromised lung functions.

Adolescent↗
PubMed1997

Relative potentiality of some contragestational agents on trauma induced deciduoma formation in immature rats.

Relative progestational and antiprogestational profile of four contragestational agents, viz. RMI-12,936, RU-38,486, STS-557 and WIN-32,729, known to possess either or both the properties in other test systems, was determined in immature rats using deciduoma induction as marker. The deciduoma was produced by needle traumatization in one of the uterine horn, and the extent of stimulation was analysed, both macro and microscopically, against the control nontraumatized horn. The results indicated that the agents which demonstrated better potentiality(ies) as progestational and/or antiprogestational in this bioassay exhibit contraceptive efficacy at relatively lower doses as compared to those that showed mild to moderate potentiality.

Animals↗
PubMed1997

Ultrastructure of intermediate trophoblast cells during morphogenesis of syncytiotrophoblast in early human pregnancy.

During human embryonic development the process of differentiation begins in the cells covering the blastocyst, resulting in the formation of outer syncytial and inner cytotrophoblastic cell layers. Although the outer syncytial layer is known to be derived from the underlying layer of mononuclear cytotrophoblasts, the cellular mechanism involved in its morphogenesis is not clear. Furthermore, there is another type of cells, designated as intermediate trophoblasts, which play a vital role in syncytium formation. Using early first-trimester (6-10 weeks' gestation) human chorionic villi, a study was carried out to illustrate the ultrastructural features of these cells. It was observed that while there was a large number of coated vesicles, vacuoles, lysosomes and dense granules in the syncytiotrophoblast, in cytotrophoblasts there was a relatively smaller number. In intermediate cells, however, these organelles were more abundant. Moreover, a discontinuity in the plasma membrane along with gap junctions was frequently observed in these cells. Since these features represent the transitional stage of a differentiating cell, it is possible that the syncytiotrophoblast is in fact formed by the differentiation of intermediate trophoblasts.

Cell Membrane↗
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

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↗
PubMed1992

Pregnane derivatives as pregnancy interceptive agents: efficacy determination on growing trophoblasts (in vitro) and in pregnant hamsters (in vivo).

An in vitro test system was standardized to study potentiality of five hormonally inert pregnane derivatives on growing trophoblasts isolated from ectoplacental cone (EPC) of day 8 hamster embryo. Cells were incubated with different concentrations of respective compounds in surface droplets. The response was determined by analyzing the sequence of changes in cell morphology like attachment, growth, proliferation, differentiation and/or degeneration within 24 or 48 h following seeding. The in vivo efficacy of these compounds was determined in hamster during peri- and immediate post-implantation periods (days 3-8 post coitum). Two compounds 88/583 and 88/585 were found to inhibit not only growth and proliferation of the cells but caused total degeneration within 24 h. The same compounds induced partial to complete resorption of the foetuses in treated animals. Whereas, the other three compounds 88/506, 88/594 and 89/43 that showed lack of comparable potentiality in vitro were found to be equally ineffective in vivo. The results indicate a positive correlationship between in vitro and in vivo activity.

Abortifacient Agents, Steroidal↗
PubMed1992

M. tuberculosis-complex specific T-cell stimulation and DTH reactions induced with a peptide from the 38-kDa protein.

An immunodominant T-cell-stimulatory epitope located near the carboxy terminus of the 38-kDa antigen from M. tuberculosis (38.G, residues 350-369) was found to be M. tuberculosis-complex specific. This was demonstrated by the presence of proliferative and delayed type hypersensitivity (DTH) responses in mice immunized with Mycobacterium tuberculosis and Mycobacterium bovis BCG, whereas mice immunized with M. avium or other non-tuberculous species of mycobacteria showed no such responses. Peptide 38.G stimulated the proliferation of peripheral blood lymphocytes from healthy purified protein derivative (PPD)-positive individuals but not from PPD-negative individuals. It also elicited DTH responses in M. tuberculosis sensitized mice and in PPD-positive healthy human volunteers. Peptide 38.G could therefore prove to be an important component in any new molecularly defined reagent used in the immunodiagnosis of tuberculous infection.

Amino Acid Sequence↗
PubMed1991

Pregnancy interceptive efficacy and biological profile of 3-amino-6,7-dimethoxy-1H-pyrazolo [3,4-b] quinoline (compound 85/83) in rodents.

Administration of compound 85/83 during the peri- and post-implantation period intercepted pregnancy in hamster and guinea pig by parenteral route and in hamster by oral route also. The m.e.d. for hamster and guinea pig was 10 and 20 mg/kg, respectively; lower doses were less effective. Restricting the administration to early post-implantation schedule interrupted pregnancy partially in both species. The compound was, however, ineffective in rat and in the pre-implantation schedule (days 1-4 post-coitum) in hamster. When tested in vitro on growing trophoblasts at 13.8 x 10(-5) M concentration, it prevented growth and caused degeneration of the cells within 24 h; lower concentration (9.2 x 10(-5) M) was less effective. The compound was found to be devoid of estrogenic, antiestrogenic, progestational and antiprogestational properties in conventional bioassays. In hormone competition assays, its relative binding affinity (RBA) to estrogen receptor was negligible (0.002% of estradiol-17 beta), while for uterine cytosol progesterone receptors in rabbit and hamster was 0.06 and 0.08% of progesterone, respectively. The compound 85/83 appears to intercept pregnancy by interfering with development of trophoblast cells.

Administration, Oral↗
PubMed1991

Ultrastructural morphology of ectoplacental cone trophoblasts of hamster embryos.

The invasiveness of trophoblast cells is well known, but it is not clear whether they achieve this property by being transformed to other cell types (like malignant ones) or remain benign. Trophoblasts, in culture, were studied ultrastructurally by examining the surface morphology of the cell vis-à-vis their cytoplasmic outgrowth, and the presence and/or absence of ruffling membranes, filopodia, microvilli, pinocytotic pits or bleb-like structures was observed. Results revealed formation of ruffling membranes only on the leading edge, a presence of slender filopodia and pinocytotic pits but an absence of microvilli and bleb-like structures, the characteristic features of a transformed cell. The study indicated that the trophoblast cells, in spite of being invasive, do not convert to any other cell type.

Animals↗
PubMed1991

Decidual cell reaction: relative response to traumatization in uterus of rat, hamster and guinea pig.

Relative decidual cell response to traumatization was studied in the uterus of immature rat, hamster and guinea pig. A single dose of progesterone (1.0 mg/animal) caused 285 +/- 41 and 459 +/- 58% uterotrophy in traumatized horn of rat and hamster respectively, while in guinea pig increasing doses of progesterone (1, 2 and 5 mg/animal), several combinations of estrogen and progesterone or alteration in treatment schedule of the two hormones as well as extending the day of traumatization failed to elicit comparable uterotrophic response. Uterus of immature hamster was found to be most responsive to traumatization and that of guinea pig the least.

Animals↗
PubMed1991

Easy criterion for detection of mating in guinea pig.

Existing criteria for determining receptivity to mating in female guinea pig has been redefined on the basis of kind of cells present in vaginal smear following its opening. The animals that showed not only cornified but also predominantly cornified cells over the leucocytes show higher sperm positivity rate. It is inferred that continuous cohabitation of these animals invariably leads to successful mating.

Animals↗
PubMed1989

Syntheses and bioevaluation of substituted dihydropyridines for pregnancy-interceptive activity in hamsters.

A number of 2,6-dimethyl-3,5-bis(methoxycarbonyl)-4-substituted-1,4- dihydropyridines were synthesized and evaluated for pregnancy-interceptive activity in mated hamsters. Out of 24 compounds, 12, 15, 21, 22, 28, and 34 caused a marked reduction in the number of implantations when administered on days 3-8 postcoitum. In an in vitro competition assay, none of the compounds exhibited noticeable binding affinity for uterine progesterone receptors. The results reported here have helped to identify new leads for developing pregnancy-interceptive agents and the active compounds do not seem to elicit their interceptive effect through receptor-mediated inhibition of progesterone action in hamster uterus.

Abortifacient Agents↗
PubMed1988

Ultrastructure of mouse ectoplacental cone cells.

Ectoplacental cone of the Muridae is an excrescence formed by proliferation of the polar trophectoderm of the bastocyst. Four types of trophoblast cells are seen in mouse ectoplacental cone on day 8 of the pregnancy: (1) trophoblast-1 at the base of the cone are polyhedral, compactly arranged and contain large nucleoli, (2) trophoblast-2 in the middle of the cone enclose several heterolysosomes, erythro-and leucophagosomes, (3) trophoblast-3, also in the middle, have several membrane-bound osmiophilic granules, (4) trophoblast-4 at the periphery of the cone are oblong and enclose many pleomorphic bodies. These morphological differences appear to be correlated with functional adaptation.

Animals↗
PubMed1987

Contraceptive and hormonal properties of a new 1,4-dihydro-2-oxoquinoline derivative (compound 84-182) in rodents and rhesus monkeys.

Compound 84-182 prevented pregnancy when administered subcutaneously at 10 mg/kg dose on days 3-8 post-coitum in hamsters and on days 6-10 post-coitum in guinea pigs. At lower doses, while in hamsters there was a marked reduction in implantation number, majority of implantations in guinea pigs showed signs of resorption. The compound was ineffective when administered at 10 mg/kg dose on days 1-3 or 6-7 post-coitum in hamsters and on days 1-5 or 4-8 post-coitum in rats. In rhesus monkeys, treatment with the compound at 5 and 10 mg/kg doses on days 16-21 of the menstrual cycle induced frank vaginal bleeding between days 21 and 24. Treatment on days 21-30 or after confirmation of pregnancy on days 32-36 was ineffective. In conventional bioassays, the compound was devoid of any estrogenic, antiestrogenic, progestational, antiprogestational, androgenic or antiandrogenic properties at the contraceptive dose. In competitive protein binding assay, the compound showed relative binding affinity (RBA) of less than 0.1% and 0.28% of progesterone, respectively, for rabbit and hamster uterine cytosol progesterone receptors. Its RBA for rat uterine cytosol estrogen receptors was less than 0.1% of estradiol-17 beta.

Animals↗