排序方式： 共有6条查询结果，搜索用时 15 毫秒
1
1.
Implantation involves a series of steps leading to an effective reciprocal signaling between the blastocyst and the uterus. Except for a restricted period when ovarian hormones induce a uterine receptive phase, the uterus is an unfavorable environment for blastocyst implantation. Because species-specific variations in implantation strategies exist, these differences preclude the formulation of a unifying theme for the molecular basis of this event. However, an increased understanding of mammalian implantation has been gained through the use of the mouse model. This review summarizes recognized signaling cascades and new research in mammalian implantation, based primarily on available genetic and molecular evidence from implantation studies in the mouse. Although the identification of new molecules associated with implantation in various species provides valuable insight, important questions remain regarding the common molecular mechanisms that govern this process. Understanding the mechanisms of implantation promises to help alleviate infertility, enhance fetal health, and improve contraceptive design. The success of any species depends on its reproductive efficiency. For sexual reproduction, an egg and sperm must overcome many obstacles to fuse and co-mingle their genetic material at fertilization. The zygote develops into a blastocyst with two cell lineages (the inner cell mass and the trophectoderm), migrates within the reproductive tract, and ultimately implants into a transiently permissive host tissue, the uterus. However, the molecular basis of the road map connecting the blastocyst with the endometrium across species is diverse (1) and not fully understood. Recent advances have identified numerous molecules involved in implantation (1-4), yet new discoveries have not yielded a unifying scheme for the mechanisms of implantation. 相似文献
2.
These experiments were undertaken to determine the potential for estradiol-17 beta (E2), 2-hydroxyestradiol-17 beta (2-OH-E2) and 4-hydroxyestradiol-17 beta (4-OH-E2) to regulate prostaglandin (PG) E and F2 alpha synthesis by pig endometrium. Endometrium was collected from pigs on d 10 of pregnancy and incubated (15 to 20 mg/well) for three 2-h periods in 2 ml of medium in 24-well culture plates. At the end of each period, the medium was removed and frozen. Later media were thawed and assayed for PGE and PGF2 alpha. During Periods 2 and 3, the medium contained 0, 25, 50, 100 or 150 microM 2-OH-E2 (Exp. 1); 0, 25 or 50 microM 4-OH-E2 (Exp. 2); or 0, 25 or 50 microM E2 (Exp. 3). Each experiment was a factorial with 2-OH-E2, 4-OH-E2 or E2 as one main effect and 0 or 1 mM ascorbate as a second main effect. Ascorbate decreased (P less than .01) PGE and PGF2 alpha release in all experiments. Two-hydroxyestradiol-17 beta decreased (P less than .01) PGE and PGF2 alpha release into the medium during Periods 2 and 3 in a dose-dependent manner (Exp. 1). In Exp. 2, 4-OH-E2 decreased (P less than .07) endometrial release of PGE and PGF2 alpha in Periods 2 and 3 and increased (P less than .01) the PGE:PGF2 alpha in Period 3. In Exp. 3, E2 decreased release of PGE during Period 3 and PGF2 alpha release during Period 2. The PGE:PGF2 alpha was not altered by E2.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
3.
Matrix metalloproteinase-2 (MMP-2) and its inhibitor, tissue inhibitor of matrix metalloproteinase 2 (TIMP2), are known to be important in cancer. The purposes of this study were to determine the cDNA sequence of canine MMP-2 and to investigate the expression patterns of MMP-2 and TIMP2 in normal canine lymph nodes and spontaneously arising canine lymphomas. We cloned and sequenced a PCR product containing most (1901 base pairs) of the coding sequence of canine MMP-2 that translates into a 623 amino acid protein. The cDNA and deduced amino acid sequences are highly homologous to those of other mammalian species. Canine MMP-2 and TIMP2 mRNAs were detectable in the majority of normal lymph node and lymphomatous samples evaluated. No statistical difference was identified when comparing the expression of either gene with regard to normal versus neoplastic nodes, nodal versus extranodal lymphoma, lymphoma grade, or B versus T cell immunophenotype. 相似文献
4.
Pig endometrial cells in primary culture: morphology, secretion of prostaglandins and proteins, and effects of pregnancy 总被引：3，自引：0，他引：3
Luminal epithelial, glandular epithelial, and stromal cells were isolated from pig endometrium by enzymatic dispersion and sieve filtration. The three cell types, maintained in primary culture, showed distinctly different morphologies when viewed by light and scanning electron microscopy. Immunocytochemical staining indicated that luminal and glandular epithelial cells were positive for both cytokeratin and vimentin. However, stromal cells were positive only for vimentin. Acid phosphatase activity was detected in the culture medium of glandular cells and increased (P less than .05) when progesterone (.1 microM) was included in the culture medium. The secretion of uteroferrin by glandular cells was also indicated by one-dimensional PAGE and Western blot analysis. Stromal cells produced more (P less than .01) prostaglandin E (PGE) than prostaglandin F2 alpha (PGF2 alpha), whereas glandular cells secreted more (P less than .01) PGF2 alpha than PGE. Pregnancy status affected prostaglandin secretion in that stromal cells secreted less (P less than .01) PGE and PGF2 alpha and glandular cells secreted less (P less than .05) PGF2 alpha when they were harvested from pregnant vs cyclic pigs. Furthermore, the PGE:PGF2 alpha ratio in medium from stromal cells was greater (P less than .01) for cells collected from pregnant pigs. This culture system provides an in vitro model for studying the hormonal regulation of the endometrium and potentially may be useful for studying interactions between endometrial cells and embryos in the pig. 相似文献
5.
Fan TM Kitchell BE Dhaliwal RS Jones PD Hintermeister JG Paria BC 《Journal of the American Animal Hospital Association》2002,38(4):357-363
Twenty cats with spontaneously arising tumors received oral lomustine at a dose range of 32 to 59 mg/m2 every 21 days. Due to biohazard concerns associated with lomustine capsule reformulation, a standardized 10-mg capsule dosage was used for all cats regardless of body weight. Severe hematological toxicity was infrequent, with the incidence of either grade III or IV neutropenia and thrombocytopenia being 4.1% and 1.0%, respectively. Cats receiving higher cumulative doses of lomustine trended toward a greater likelihood for progressive neutropenia (P=0.07). Two cats with lymphoma, two cats with fibrosarcoma, and one cat with multiple myeloma achieved a measurable partial response to lomustine therapy. Cats treated with higher dosages of lomustine trended toward statistically significant higher response rates (P=0.07). 相似文献
6.
Effect of polysaccharides extracts of algae Ulva rigida on growth,antioxidant, immune response and resistance of shrimp,Litopenaeus vannamei against Photobacterium damselae 
下载免费PDF全文
下载免费PDF全文 This study was carried out to investigate the effect of water‐soluble polysaccharides extract of algae Ulva rigida (WPU) as dietary supplement on growth performance, antioxidant enzyme activity, lysozyme and phenoloxidase activity, and resistance of shrimp (Litopenaeus vannamei) subjected to bacterial infection with Photobacterium damselae. Three replicate groups of shrimp (1.0 g) were fed four diets containing four levels, 0 or control, 0.5, 1 and 1.5 g/kg of WPU for 8 weeks over the growth trial. Thereafter, 30 shrimps from each dietary treatment were infected with bacteria P. damselae to evaluate disease resistance of infected shrimp. The results of this study showed that WPU was effective as a growth promoter for L. vannamei. The best growth rate was observed in shrimp fed 1.5 g/kg of WPU diet. Regarding antioxidant defences, the diets supplemented with three levels of WPU stimulated glutathione peroxidase and catalase activates in experimental shrimps. MDA content of L. vannamei‐fed diet containing WPU 1.5 and WPU 1.0 was lower than WPU 0 and WPU 0. 5 diets. Also, lysozyme and phenoloxidase activities of shrimp receiving WPU at 1.0 and 1.5 level were significantly higher than those fed WPU 0 and WPU 0.5 diets. In addition, using WPU extract in all diets decreased mortality in L. vannamei in a dose‐dependent manner after challenge with P. damselae. These results suggest that incorporation of water‐soluble polysaccharides from green algae U. rigida at 1.5 g/kg doses improves growth and antioxidant activity and enhances the immune responses in shrimp L. vannamei. 相似文献
1