Tag Archives: follicle (Part 5)

Vascular Remodeling and Angiogenesis: INTRODUCTION(4)

The aim of this study was to investigate the angiogenic processes that occur after ovary xenotransplantation in order to find a way to protect ovarian grafts from posttransplantation damage. The experimental model of rat ovaries transplanted into immunodeficient mice was used for monitoring vascular remodeling by magnetic resonance imaging (MRI) and histology. The rat ovarian cycle is well defined and has been studied extensively, including some MRI studies on ovarian angiogenesis, while the nude mice provide a good model for MRI studies of angiogenesis of tumor xenografts. The ovaries were transplanted into two sites that represent tissues abundantly (intramuscular) or poorly (subcutaneous) vascularized.

Vascular Remodeling and Angiogenesis: INTRODUCTION(3)

INTRODUCTION(3)

One of the most important factors for successful ovarian graft transplantation is the rapid establishment of a rich blood supply, which is crucial for survival of the ovarian follicles. Without vascular anastomosis, grafts are solely dependent on posttransplantation vascularization. Dissen et al. showed that transplanted immature rat ovaries become profusely revascularized within 48 h after autotransplantation. Vascular growth was accompanied by increased expression of genes that encode the angiogenic factors, vascular endothelial growth factor (VEGF), and transforming growth factor-^1 (TGFp-1). An important issue in ovarian transplantation is follicle survival. Transplantation of fresh mouse ovaries resulted in 50% reduction in follicle numbers. In another study, only 35% of the oocytes survived fresh sheep tissue grafting into SCID mice. In both studies, the grafts were transplanted into the well-vascularized kidney capsule. buy lipitor cheap

Vascular Remodeling and Angiogenesis: INTRODUCTION(2)

The procedure of ovarian tissue cryopreservation permits retention of hundreds of immature oocytes kept within the protective environment of the original ovarian tissue. An important advantage of this technique is the lack of unnecessary delays in providing anticancer treatment. Additionally, because the primordial follicles are small and structurally simple, they are much more tolerant to manipulation and to the freeze-thaw procedure compared with the large growing follicles that readily undergo atretic degeneration and granulosa cell apoptosis.

Vascular Remodeling and Angiogenesis: INTRODUCTION(1)

INTRODUCTION(1)

Advances in cancer diagnosis and treatment have greatly enhanced the life expectancy of premenopausal women who suffer from malignant diseases. As a result of the increase in long-term survival, posttreatment quality of life is becoming an urgent issue. Side effects of cytotoxic anticancer treatments frequently include ovarian damage due to the susceptibility of the ovaries to ionizing radiation and alkylating agents. These anticancer treatments can damage both the reproductive and the endocrine functions of the ovaries. It has been reported that 34% of cancer patients who received conventional chemotherapy suffered from ovarian failure. Ovarian failure was also observed in 92% of the patients who received radio/chemotherapy required before bone marrow transplantation. canadian health and care mall

Role and Gonadotrophic Regulation of X-Linked: DISCUSSION(6)

DISCUSSION(6)

Previous studies from our laboratory have shown that FSH increases follicular transforming growth factor a secretion and that this theca-derived growth factor induces follicular growth in vitro. In this context, recent studies using a coculture of bovine ovarian granulosa and theca cells have shown that the theca cells are essential in protecting granulosa cells from undergoing apoptosis, a process that is follicular stage-specific. These results suggest that theca cells may secrete one or more survival factors necessary for maintenance of granulosa cell viability, although the identity of this factor is yet to be defined. It is also possible that the regulation of follicular growth by FSH is mediated by the action of TNFa. buy Endep online

Role and Gonadotrophic Regulation of X-Linked: DISCUSSION(5)

Our present findings indicate that although FSH is capable of increasing follicular cell number (as indicated by increased Alamar Blue reduction and DNA content) and growth in a follicle culture system, it fails to stimulate proliferation when added to granulosa cell primary cultures. The reason for this apparent discrepancy is not clear, but the granulosa cells used in the present studies may have been exposed to LH (in the eCG preparation) in vivo before isolation and culture, resulting in premature luteinization of the cells and, consequently, exit from the cell cycle. cialis super active canada

Role and Gonadotrophic Regulation of X-Linked: DISCUSSION(4)

DISCUSSION(4)

Specifically, XIAP possesses two different caspase-inhibitory activities, which can be attributed to distinct domains within XIAP. The BIR3 of XIAP is a specific inhibitor of cas-pase-9, whereas BIR2 plus the linker region of BIR1 and BIR2 is specific for caspase-3 and caspase-7. The IAPs suppress Fas ligand- and TNFa-induced apoptosis by directly inhibiting caspase-3 and caspase-7 activation and activity, but they are ineffective in the activation of caspase-1, caspase-6, or caspase-10. generic female Viagra

Role and Gonadotrophic Regulation of X-Linked: DISCUSSION(3)

Follicles infected with XIAP sense and cultured in the presence of low FSH concentration (5 ng/ml) showed a marked increase in follicular development (as evidenced by increases in DNA content and follicular volume) compared to the FSH-stimulated but LacZ-infected follicles. The XIAP sense was ineffective in the absence of gonadotropin. These findings suggest that whereas XIAP is necessary for the suppression of apoptosis, it alone is insufficient to promote follicular growth. These findings do not exclude the possible involvement of other IAPs in the gonadotrophic regulation of follicular development and atresia. generic Kamagra online

Role and Gonadotrophic Regulation of X-Linked: DISCUSSION(2)

DISCUSSION(2)

Transgenic and knockout animals have been used extensively to assess the role of the gene (or genes) of interest in physiological processes. However, these approaches are often plagued with systemic complications because of overall ill health of the animals, which often affects normal development. The IAPs are ubiquitous and found in high abundance in proliferating mammalian cells. Despite a newly established NAIP knockout mice model, no XIAP knockout animal model was available until recently to enable assessment of the role of XIAP in the gonadotrophic regulation of follicular development and atresia. Whereas no apparent differences were observed between the ability of cells from the XIAP-deficient and wild-type mice to undergo caspase-dependent or -independent apoptosis, the cellular levels of other IAPs (e.g., cIAP-1 and cIAP-2) were unexpectedly higher, suggesting the existence of a possible compensatory mechanism that leads to the up-regulation of other IAP family members when XIAP expression is lost. generic levitra canada

Role and Gonadotrophic Regulation of X-Linked: DISCUSSION(1)

The FSH is an important survival factor for preantral and antral follicular development in vivo. Whereas administration of gonadotropin induces ovarian follicular development in immature animals, gonadotropin withdrawal by anti-eCG antibody treatment resulted not only in cessation of follicular growth but also in atresia. In the present study, we have successfully established a rat follicle culture system and have demonstrated that FSH stimulates rat ovarian follicular growth and induces antral formation in a 6-day culture period. Our findings are consistent with the results of recent studies involving cultures of bovine, baboon, mouse, rat, and hamster ovarian follicles. This culture system may prove to be useful for assessment of the endocrine control of follicular development and atresia. Levitra professional Canadian pharmacy

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