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The freezing of ovarian tissue and the growth of immature oocytes from primordial follicles is an interesting concept in ovarian tissue transplantation and in-vitro fertilization. In this study, the morphology and distribution of primordial follicles were studied in ovarian tissue from 24 women before and after cryopreservation. Cryopreservation did not significantly change either the morphology or number per unit volume of morphologically normal follicles in frozen ovarian tissue. Primordial follicles were predominant, accounting for 78.6% and 82.6% of total follicles in fresh and frozen ovarian tissues respectively. The distribution of follicles was extremely uneven in ovarian tissue. A large variation in follicle numbers was observed in ovarian tissue samples from patient to patient, and even in the same patient, indicating that the number of follicles counted in one sample of ovarian tissue may not represent the number of follicles in other tissue samples. Ovarian tissue could be frozen in the form of strips instead of fragments for fast processing and better viability of ovarian tissue in cryopreservation. The number of follicles in ovarian tissue declined with the increasing age of the patients. An immunohistochemical study showed that immunoreactivity for the epidermal growth factor (EGF) receptor was detected in primordial follicles of adult ovarian tissue. EGF receptor staining was most intense in the oocytes of primordial follicles. Weak staining for EGF receptor was observed in some surrounding pregranulosa cells. Immunohistochemical staining for EGF receptor was also present in the stromal cells of ovarian tissue, but to a much lesser degree. There was no significant difference in the immunohistochemical staining for EGF receptor in ovarian tissue before and after cryopreservation.

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For patients who are planning to have chemotherapy, radiotherapy or to undergo bilateral oophorectomy, the loss of ovarian function will result in premature ovarian menopause and loss of fertility. Embryo preservation is not an option for single women or married women because delaying treatment for at least 2 months of in-vitro fertilization cycles is inappropriate and may be life-threatening. This study reports on the indications for ovarian tissue cryobanking and the state of the art of this method in preserving fertility in women with iatrogenic premature menopause.

The in-vitro growth of immature oocytes in early follicles from cryopreserved human ovarian tissues is a new concept in in-vitro fertilization programmes for the treatment of infertile and cancer patients. To better understand the regulatory mechanism of follicular development, immunohistochemistry was used to study the expression of insulin-like growth factor (IGF) type I receptor (IGF-IR) and transforming growth factor-beta (TGFbeta) type I (TbetaR-I) and type II (TbetaR-II) receptors in fresh and frozen ovarian tissues from 14 women. Immunoreactivities for IGF-IR and TbetaR-I were present simultaneously in the oocytes of primordial, pre-antral and antral follicles. Staining for both IGF-IR and TbetaR-I was also observed in granulosa cells of primordial, pre-antral and antral follicles. IGF-IR and TbetaR-I also stained in thecal cells of pre-antral and antral follicles. Stromal cells in surrounding ovarian tissue expressed IGF-IR and TbetaR-I at various follicular stages. Unlike TbetaR-I, TbetaR-II was expressed only in the oocytes of primordial and primary follicles, and with weak staining intensity in thecal cells. No significant staining for TbetaR-II was found in oocytes and granulosa cells of antral follicles. There was no difference in staining patterns for IGF-IR, TbetaR-I and TbetaR-II between fresh and frozen ovarian tissues, indicating that cryopreservation might not significantly alter the immunoreactivities of these receptors in frozen ovarian tissue. The results suggest that IGF-I and TGFbeta may participate in the regulation of follicular growth by binding to their receptors through an autocrine or paracrine mechanism. IGF-I and TGFbeta may be useful in regulating the in-vitro or in-vivo maturation of oocytes not only in later follicles but also very early follicles, from cryopreserved ovarian tissues for clinical use in the future.

Avermectins (AVMs) are the active components of some insecticidal and nematicidal products used in agriculture and veterinary medicine for the prevention of parasitic diseases. Residues of AVM drugs or their metabolites in livestock feces have toxic effects on non-target aquatic and terrestrial organisms. In this study, oxidative stress responses and pathological changes on pigeon brain tissues and serum after subchronic exposure to AVM for 30, 60 and 90 days were investigated. The decrease in antioxidant enzyme (superoxide dismutase, SOD and glutathione peroxidase, GSH-Px) activities and increase in methane dicarboxylic aldehyde content in a dose-time-dependent manner in the brain and serum of pigeon were observed. The protein carbonyl content, an indicator of protein oxidation, and DNA-protein crosslink coefficient were significantly augmented with dose-time-dependent properties. The microscopic structures of the cerebrum, cerebellum and optic lobe altered obviously, the severity of which increased with the concentration of AVM and exposure time. The results imply that AVM could induce oxidative damage to the brain tissue and serum of pigeon. The information presented in this study is helpful to understand the mechanism of AVM-induced oxidative stress in birds.

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In this study bioactive inhibin was measured in 112 serum samples from 103 pregnant women by a sensitive ovine pituitary cell culture system. Human inhibin activities were detected in a range between 0.02-5.28 U/mL at six dilutions by using serum from the 38-week pregnant women as a quality control. A remarkable increase in serum inhibin was observed from 4 to 38 weeks of pregnancy. The mean serum inhibin level was 1.58 U/mL at 4 weeks. Thereafter, inhibin levels increased progressively with the weeks of pregnancy (r = 0.988; P less than 0.001). In the midterm of pregnancy, serum inhibin was elevated at average levels of 2.84 and 3.84 U/mL at 20 and 28 weeks, respectively. The peak level of inhibin (5.33 U/mL) was obtained at 38 weeks, which was an increase of 237% compared to that at 4 weeks. The average rate of increase in serum inhibin levels was 14.51% every 2-4 weeks (ranging from 8.1-20%). These findings suggest that circulating inhibin is useful marker during human pregnancy.