Nasopharyngeal carcinoma (NPC) occurs occasionally in the west but is popular in south-eastern China and Hong Kong where it is the third most common form of malignancy among ethnic Chinese people. The possibly relevant factors associated with NPC have been found, for example, environment, genetics and EB virus, etc. Recently, as a result of improved environment of living and therapies, the death rate of NPC is decreasing year by year. However, the molecules mechanism underlying its tumorigenicity is still unclear. The p57 protein is a maternally expressed, paternally imprinted cyclin-dependent kinases inhibitor (CDI). p57 mutations are rare in the human cancers, suggesting that other mechanisms of transcriptional or post translational silencing are involved in the loss of p57 function. Decreased expression of p57 has been found in Beckwith-Wiedemann syndrome (BWS), gastric cancer and bladder carcinoma. So far, many studies in signal transduction have been focused on p21 or p27. The relationship between p57 expression and signal transduction and cell proliferation under physiological circumstances requires further exploration. Studies of the relationship between hormones and cancers have been proceeded for years, nevertheless, there is few about NPC. We examined several hormones¡¦ effect on the NPC cell lines. We found that in response to progesterone treatment were the marked inhibition of pMAPK and up-regulation of p57, just like the influence of MEK inhibitor, U0126. Progesterone also induced growth inhibition and a slight accumulation of cells in the G1 phase of the cell cycle. On the other hand, the effects of progesterone were diminished in the presence of its antagonist mifepristone (RU-486). Taken together, these results suggest that progesterone treatment may induce the expression of the p57 on the mRNA and protein level by the progesterone receptor and that the MAPK signaling pathway may be involved in the progesterone-induced antiproliferative effect.

Progesterone is unequivocally required for the establishment and maintenance of pregnancy in all mammals studied. Its known functions are complex and encompass global changes in gene expression. Therefore, studies were conducted to characterize the effects of progesterone on expression of genes for endometrial factors having roles in conceptus growth, implantation and establishment of pregnancy. The first study characterized the effect of an artificially induced early increase in circulating progesterone on conceptus growth and development and regulation of expression of galectin-15 (LGALS15), a recently identified protein secreted by the ovine uterine luminal epithelium (LE). Exogenous progesterone beginning on Day 1.5 post-mating accelerated conceptus development on Days 9 and 12. On Day 12 the conceptus was functionally and morphologically advanced to produce greater quantities of interferon tau (IFNT) than blastocysts from control ewes. Further, the endometrium responded to early progesterone and IFNT with early expression of cathepsin L (CTSL), radical S-adenosyl methionine domain containing 2 (RSAD2), and LGALS15 within the endometrium. The second study identifed structural changes within the luminal epithelium which could alter the flux of factors into and out of the uterine lumen to maintain appropriate fetal/maternal communication. In this study, progesterone reduced quantities of proteins associated with both tight and adherens junctions during the elongation period. IFNT subsequently increased these proteins after conceptus elongation. The third and fourth studies identified progesterone-regulated genes which have been implicated as having importance to implantation in sheep, mouse, and human. WNT signaling was transiently downregulated by progesterone, while members of several growth factor families are upregulated including insulin-like growth factor binding proteins (IGFBPs) 1 and 3, hepatocyte growth factor (HGF) and fibroblast growth factor 7 (FGF7), which may enhance conceptus growth. Collectively, these studies assess the role of progesterone in altering gene uterine expression to establish a favorable environment for conceptus development. The long-term goals of these studies are to establish biomarkers of receptivity to conceptus development and implantation, enhance our understanding of gene and pathway regulation in early pregnancy loss, and identify genes which may be targeted in therapeutic strategies to improve reproductive success in humans and animals.

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains vi, 44 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 35-43).

Thesis--M. Phil., University of Hong Kong. / Typescript.

Thesis--M. Phil., University of Hong Kong. / Typewritten.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 170-197). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 170-197). Also available on the Internet.

No description available.

The object of this investigation was to measure the changes in plasma corticoids and progesterone, at two different levels of energy intake during the postpartum period in beef heifers and to assess their relationship to breeding efficiency. Blood samples were taken using a tail bleeding method from 26 first calf crossbred heifers within 24 hours postpartum. Sampling was continued twice weekly until each animal was diagnosed pregnant. Plasma samples were analyzed for progesterone and corticoids using competitive binding techniques. Progesterone levels increased from .5 ng/ml postpartum to 3.7 ng/ml following first ovulation. These levels remained high if conception occurred (5.0 + ng/ml) or returned to minimum levels for repeat estrous cycle. Due to the necessary manipulation of the animals, postpartum plasma levels of corticoids fluctuated widely (10 ng/ml to 70 ng/ml) for each animal. Corticoids means were lower during the postpartum anestrum than during subsequent estrous cycles. No significant correlations were found between plasma corticoids and progesterone concentrations. Providing more than NRC recommended energy intake had no influence on breeding efficiency.

No description available.