The axoneme central apparatus is thought to control flagellar/ciliary waveform and maintain the structural integrity of the axoneme, but proteins involved in these processes have not been fully elucidated. Moreover the network of interactions among them that allows these events to take place in a compact space has not been defined. PF6, a component of the Chlamydomonas central apparatus, is localized to the 1a projection of the C1 microtubule. Mutations in the Chlamydomonas PF6 gene result in flagellar paralysis. We characterized human and murine orthologues of PF6. The murine Pf6 gene is expressed in a pattern consistent with a role in flagella and cilia, and the PF6 protein is indeed localized to the central apparatus of the sperm flagellar axoneme. We discovered that a portion of PF6 associates with the mammalian orthologue of Chlamydomonas PF16 (sperm-associated antigen 6 (SPAG6)), another central apparatus protein that is localized to the C1 microtubule in algae. A fragment of PF6 corresponding to the PF6 domain that interacts with SPAG6 in yeast two-hybrid assays and colocalizes with SPAG6 in transfected cells was missing from epididymal sperm of SPAG6-deficient mice. SPAG6 binds to the mammalian orthologue of PF20, which in Chlamydomonas is located in bridges connecting the C2 and C1 microtubules. Thus, PF6, SPAG6, and PF20 form a newly identified network that links together components of the axoneme central apparatus and presumably participates in its dynamic regulation of ciliary and flagellar beat. Molecular & Cellular Proteomics 4:914 -923, 2005.Cell motility and the movement of surface fluids are dependent upon flagella and cilia. The core structure of these organelles, the axoneme, is remarkably conserved across species, having in common nine doublets of microtubules with the associated force-generating dynein arms and radial spokes surrounding two central singlet microtubules (the central apparatus), which contain associated proteins (1-10). The central apparatus is thought to play a key role in translating the microtubule sliding caused by dynein into the flagellar waveform and maintaining structural integrity of the axoneme (9, 10). However, the central apparatus proteins involved in these processes have not been fully elucidated, and the network of interactions among them that allows these events to take place in a compact space has not been defined. PF6, a component of the Chlamydomonas central apparatus, is localized to the 1a projection of the C1 microtubule (11). The Chlamydomonas pf6 mutant has paralyzed flagella and lacks the 1a projection, indicating that PF6 has a critical role in axoneme structure and function. We characterized the human and murine orthologues of PF6 and demonstrated that the murine Pf6 gene is expressed in a pattern consistent with a role in flagella and cilia and that PF6 protein is indeed localized to the central apparatus of the sperm flagellar axoneme. We discovered that murine PF6 directly associates with the mammalian orthologue of Chlamydomonas PF16 (SPAG6) 1 (1...

BACKGROUND Freeze-all IVF cycles are becoming increasingly prevalent for a variety of clinical indications. However, the actual treatment objectives and preferred treatment regimens for freeze-all cycles have not been clearly established. OBJECTIVE AND RATIONALE We aimed to conduct a systematic review of all aspects of ovarian stimulation for freeze-all cycles. SEARCH METHODS A comprehensive search in Medline, Embase and The Cochrane Library was performed. The search strategy included keywords related to freeze-all, cycle segmentation, cumulative live birth rate, preimplantation genetic diagnosis, preimplantation genetic testing for aneuploidy, fertility preservation, oocyte donation and frozen-thawed embryo transfer. We included relevant studies published in English from 2000 to 2018. OUTCOMES Our search generated 3292 records. Overall, 69 articles were included in the final review. Good-quality evidence indicates that in freeze-all cycles the cumulative live birth rate increases as the number of oocytes retrieved increases. Although the risk of severe ovarian hyperstimulation syndrome (OHSS) is virtually eliminated in freeze-all cycles, there are certain risks associated with retrieval of large oocyte cohorts. Therefore, ovarian stimulation should be planned to yield between 15 and 20 oocytes. The early follicular phase is currently the preferred starting point for ovarian stimulation, although luteal phase stimulation can be used if necessary. The improved safety associated with the GnRH antagonist regimen makes it the regimen of choice for ovarian stimulation in freeze-all cycles. Ovulation triggering with a GnRH agonist almost completely eliminates the risk of OHSS without affecting oocyte and embryo quality and is therefore the trigger of choice. The addition of low-dose hCG in a dual trigger has been suggested to improve oocyte and embryo quality, but further research in freeze-all cycles is required. Moderate-quality evidence indicates that in freeze-all cycles, a moderate delay of 2–3 days in ovulation triggering may result in the retrieval of an increased number of mature oocytes without impairing the pregnancy rate. There are no high-quality studies evaluating the effects of sustained supraphysiological estradiol (E2) levels on the safety and efficacy of freeze-all cycles. However, no significant adverse effects have been described. There is conflicting evidence regarding the effect of late follicular progesterone elevation in freeze-all cycles. WIDER IMPLICATIONS Ovarian stimulation for freeze-all cycles is different in many aspects from conventional stimulation for fresh IVF cycles. Optimisation of ovarian stimulation for freeze-all cycles should result in enhanced treatment safety along with improved cumulative live birth rates and should become the focus of future studies.

The use of testicular spermatozoa for IVF/intracytoplasmic sperm injection (ICSI) is currently indicated exclusively for patients with azoospermia, since a favourable outcome is expected even when very few spermatozoa are present in the ejaculate. Here, a series of four couples with long-standing male factor infertility and multiple failed IVF/ICSI cycles are described. In all couples, the use of ejaculated spermatozoa for ICSI resulted in poor embryo quality and repeated implantation failure. Testicular sperm aspiration was performed in subsequent cycles, and testicular spermatozoa were used for ICSI. Embryo implantation and ongoing pregnancies/deliveries were achieved in all four couples. It is postulated that spermatozoa are subjected to post-testicular damage during sperm transport between the seminiferous tubules and epididymis, with the injection of damaged spermatozoa being the cause for repetitive IVF/ICSI failures. In selected patients, the use of testicular spermatozoa for IVF/ICSI should be considered, even when motile spermatozoa can be identified in the ejaculate.

Spontaneous ovulation during a natural menstrual cycle represents a simple and efficient method for synchronization between frozen embryos and the endometrium. The objective was to compare serial monitoring until documentation of ovulation, with human chorionic gonadotrophin (HCG) triggering, for timing frozen embryo transfer (FET) in natural cycles (NC). In a retrospective study, 112 women with regular menstrual cycles undergoing 132 NC-FET cycles were divided into two groups: group A (n = 61) patients had FET in an NC after ovulation triggering with HCG; group B (n = 71) patients had FET in an NC after spontaneous ovulation was detected. The main outcome measure was the number of monitoring visits at the clinic. Patients in both groups were similar in terms of demographic characteristics and reproductive history. Clinical and laboratory characteristics of fresh and frozen cycles were also found comparable for both groups, as were pregnancy and delivery rates. The number of monitoring visits in group A (3.46 +/- 1.8) was significantly lower than in group B (4.35 +/- 1.4) (P < 0.0001). In patients undergoing NC-FET, triggering ovulation by HCG can significantly reduce the number of visits necessary for cycle monitoring without an adverse effect on cycle outcome. Ovulation triggering can increase both patient convenience and cycle cost-effectiveness.