User:Eleanorlucy/sandbox

This is my sandbox.

Chemotherapy and Ovarian Follicle Activation[edit | edit source]
As well as having many genetic causes, premature ovarian failure has been shown to be a side effect of many chemotherapeutic agents. - ref 13. The damage suffered by ovaries appears to be dose-dependent, and a class of chemotherapy drugs known as alkylating agents, seem to cause the most damage to the ovary and follicles. There are two ways in which this damage occurs: Chemotherapeutic agents, such as Cyclophosphamide, have been shown to activate the PI3K/PTEN/Akr pathway, which is the main pathway involved in keeping the follicles dormant and permitting them to grow - activation of this pathway encourages more primordial follicles to grow and develop.. - ref 13. These growing follicles may then be destroyed in subsequent rounds of chemotherapy, which often target growing cells, which will then cause more primordial follicles to differentiate and grow to replace the destroyed cells. This concept, known as burnout, leads to a depletion of the ovarian reserve and results in premature ovarian failure.
 * 1) By direct damage to the primordial follicle, causing cell death by toxicity
 * 2) By indirect damage to the stromal cells which surround the follicle and support it, to allow it to grow. Loss of these supporting cells then leads to death of the follicle.

Oocyte cryopreservation[edit | edit source]
Oocyte cryopreservation is a preservative process which can be used as a way of preserving fertility in children treated for childhood or adolescent cancer, and to avoid the damage caused to the ovaries caused by cytotoxic drugs often used in chemotherapy. - ref14. There are several methods of cryopreservation, each with different levels of effectiveness. After cryopreservation, the ovarian tissue must be placed back into the patient, in order to allow the ovary to function normally again and regain fertility.

Restoration of Ovarian Activity after Cryopreservation[edit | edit source]
Restoration of the ovarian function occurs in almost all cases of cryopreservation, but it takes a while for the ovarian follicles to regain full function. In all cases of successful function restoration, it took 3.5-6.5 months after reimplantation before a rise in oestrogen, a key hormone produced by the ovary, and a decrease in follicle stimulating hormone (FSH) were detected. The variation in time difference may be due to differences in the follicular reserves in the women at the time of cryopreservation. - ref 14.