Ambulatory hysteroscopy and its role in the management of abnormal uterine bleeding.

Hysteroscopy is now an ambulatory procedure, having moved from a conventional day-case operating theatre environment to the outpatient clinic setting. Outpatient hysteroscopy can be used as a diagnostic test and as a therapeutic modality for women presenting with abnormal uterine bleeding. In many cases women can be diagnosed and treated efficiently during a single hospital appointment. This article reviews the development of ambulatory hysteroscopy and how it should optimally be performed and implemented. The contemporary role of this technology for investigating and treating women with abnormal uterine bleeding is then discussed.

The role of ambulatory hysteroscopy in reproduction.

Hysteroscopy is a mainstay of modern gynaecologic practice. However, the role of ambulatory hysteroscopy and associated procedures has increased dramatically in recent years. The outpatient setting has associated benefits, both for the patient and economically. The advent of less invasive vaginoscopic techniques means that diagnostic hysteroscopy is achievable safely, comfortably and efficiently in almost all women and avoids the risk of a general anaesthetic. This review aims to summarise first the role for ambulatory hysteroscopy in diagnosis of conditions contributing to reproductive failure. The second section of the review concentrates on the therapeutic interventions that can be performed hysteroscopically in the ambulatory setting such as tubal catheterisation, tubal occlusion and uteroplasty. Lastly, we discuss the role outpatient hysteroscopy plays in established contraceptive techniques such as intrauterine device placement, and the more recent advent of hysteroscopic sterilisation.

The role of neurotrophin receptors in female germ-cell survival in mouse and human.

During mammalian ovary formation, the production of ovarian follicles is accompanied by an enormous loss of germ cells. It is not known how this loss is regulated. We have investigated the role of the Trk tyrosine kinase receptors, primarily TrkB, in this process. The ovaries of TrkB-/- and TrkC-/- mice with a mixed (129Sv x C57BL/6) genetic background were examined shortly after birth. Around 50% of TrkB-/- mice had grossly abnormal ovaries that contained greatly reduced numbers of follicles. No defects were found in the ovaries of TrkC-/- mice. Congenic TrkB-/- mice were generated on 129Sv and C57BL/6 backgrounds: whereas the former had a mixed ovarian phenotype similar to that of the original colony of mice, the ovaries of all offspring of the C57BL/6 congenic line contained reduced numbers of follicles. RT-PCR showed that mRNA encoding TrkB and its two ligands, neurotrophin 4 (NT4) and brain-derived neurotrophic factor (BDNF), were present throughout the period of follicle formation in the mouse. In situ hybridisation showed that TrkB was expressed primarily in the germ cells before and after follicle formation. Mouse neonatal and fetal ovaries and human fetal ovaries were cultured in the presence of K252a, a potent inhibitor of all Trk receptors. In mice, K252a inhibited the survival of germ cells in newly formed (primordial) follicles. This effect was rescued by the addition of basic fibroblast growth factor (bFGF) to the culture medium. Combined addition of both BDNF and NT4 blocking antibodies lowered germ-cell survival, indicating that these TrkB ligands are required in this process. The results indicate that signalling through TrkB is an important component of the mechanism that regulates the early survival of female germ cells.

The human fetal testis is a site of expression of neurotrophins and their receptors: regulation of the germ cell and peritubular cell population.

In the fetal testis, organization of the tissue into two compartments consisting of cords containing Sertoli and germ cells surrounded by peritubular cells and of other cells within the interstitium is essential for subsequent function. Neurotrophins (NTs) act as survival and differentiation factors in the nervous system and have been detected in the developing rodent testis. Expression of mRNA for nerve growth factor; NTs 3 and 4 and brain-derived neurotrophic factor; the high-affinity receptors TrkA, TrkB, and TrkC; and the low-affinity p75 receptor were detected in the human testis between 14 and 19 wk gestation. NT4 mRNA and protein were predominantly localized to the peritubular cells. These cells were also the site of expression of p75. By contrast, nerve growth factor and NT3 were mainly expressed in Sertoli and interstitial cells. Treatment of testis organ cultures with the Trk-specific kinase inhibitor K252a resulted in a marked decrease in both gonocyte and peritubular cell number and proliferation with little effect on Sertoli cells. These data demonstrate the expression of NTs and their receptors in the human fetal testis during the second trimester and indicate possible roles in the regulation of proliferation and survival of germ cells and peritubular cells.

Differential expression of two estrogen receptor beta isoforms in the human fetal testis during the second trimester of pregnancy.

Testicular cancer is more common in individuals with disorders of the male reproductive tract. It has been suggested that inappropriate exposure to estrogens during fetal life may have an impact on maturation of testicular germ cells that are the cells of origin of the majority of testis cancers. The aim of the present study was to establish whether human fetal germ cells (gonocytes) are a potential target of estrogen action. To address this issue, we used RT-PCR and immunohistochemistry to examine the pattern of expression of estrogen receptors (ER alpha, ER beta, and ER beta 2 variant) in human fetal testes at 12-19 wk gestation. ER alpha, mRNA, and protein were not detected in any of the fetal testes. In contrast, using an antibody directed against the hinge domain of ER beta expression was detected in multiple testicular nuclei. RT-PCR with primers specific for full-length wild-type ER beta (ER beta 1) or the ER beta 2 variant formed by splicing of an alternative eighth exon, was performed on whole-tissue extracts and materials recovered by laser capture and revealed that mRNAs for both isoforms were expressed. Immunohistochemistry with isotype-specific monoclonal antibodies showed that ER beta 1 was low/undetectable in gonocytes, whereas these cells expressed the highest levels of ER beta 2, compared with other testicular cell types. Both ER beta 1 and ER beta 2 were detected in some but not all Sertoli cells, peritubular cells, and other interstitial cells including those tentatively identified as Leydig cells. Our immunohistochemical results demonstrate that during the second trimester, some but not all somatic cells within the human fetal testis express wild-type ER beta (ER beta 1) protein and/or the variant isoform of ER beta (ER beta 2) that lacks amino acids essential for binding of estradiol. ER beta 2 protein was readily detectable in fetal gonocytes, whereas ER beta 1 was not. We did not detect expression of ER alpha. The expression of ER beta 2, a variant proposed act as a dominant negative receptor, might prevent estrogen action in gonocytes. We suggest that during this period of fetal life, estrogenic ligands are most likely to act on somatic cells that contain ER beta 1 protein.

Neurotropins and their receptors are expressed in the human fetal ovary.

Mammalian ovarian development is characterized by a sequential pattern of mitotic proliferation of oogonia, initiation then arrest of meiosis, and primordial follicle formation. The factors regulating these processes are poorly understood. The neurotropins are survival and differentiation factors in the nervous system, acting via high affinity receptors of the trk protooncogene family and the low affinity p75 nerve growth factor receptor, and have also been described in the rodent ovary, where changes in NT4/TrkB gene expression have been detected at the time of primordial follicle formation. There are no data on neurotropin expression in the normal human ovary. We have investigated the expression and localization of neurotropins and their receptors in the midtrimester human fetal ovary (13-21 wk gestation). Expression of mRNA for neurotropins and their receptors was detected by RT-PCR. Clusters of oogonia were found to be the predominant site of NT4 mRNA expression using in situ hybridization. However, at later gestations granulosa cells of primordial follicles showed increased expression, with lesser expression in the enclosed oocytes. NT4 protein was also localized to the granulosa cells by immunohistochemistry and at earlier developmental stages to epithelioid cells, which were mingled with clusters of oogonia not expressing NT4. TrkB receptor protein was localized by immunohistochemistry to germ cells at all gestations examined. The p75 nerve growth factor receptor protein was exclusively expressed in the ovarian stroma. These data demonstrate the expression of neurotropins and their receptors within the human fetal ovary. Developmental changes in the pattern of expression of NT4 around the time of primordial follicle formation suggest that neurotropins may be involved in signaling between somatic cells and germ cells at this crucial stage of ovarian development.