Usefulness of expanding the indications of early rescue intracytoplasmic sperm injection.

Purpose: Early rescue intracytoplasmic sperm injection (ICSI) is often performed in cases in which not even a single oocyte has extruded a second polar body 6 h after insemination. We evaluated the usefulness of expanding the indications of early rescue ICSI to cases in which <80% of oocytes have extruded second polar bodies 6 h after insemination. Methods: Early rescue ICSI was performed on oocytes that were denuded 2.5 h post-insemination and whose extrusion of the second polar bodies had been examined 6 h post-insemination with a PolScope. Results: In vitro fertilization was performed on 24 496 oocytes of 4944 cycles, and 1438 cycles had <80% rate of the second polar body extrusion. Rescue ICSI was performed on 3933 oocytes. Three pronuclei (3PN) incidence of rescue ICSI was 3.0% in oocytes with ≥50% rate of the second polar body extrusion. With respect to the second polar body extrusion rate, no differences were observed in normal fertilization, blastocyst development, implantation, miscarriage, or live birth rates for rescue ICSI. Conclusion: By expanding the indications of early rescue ICSI using the PolScope to cases in which <80% of oocytes have extruded the second polar bodies, many fertilized oocytes can be obtained without considerably increasing the 3PN rate.

Early rescue oocyte activation for activation-impaired oocytes with no second polar body extrusion after intracytoplasmic sperm injection.

PURPOSE: When rescue artificial oocyte activation (ROA) is performed on the day after intracytoplasmic sperm injection (ICSI) or later, embryonic development is poor and seldom results in live births. The efficacy of an early ROA after ICSI is unclear. Is early ROA effective in rescuing unfertilized oocytes that have not undergone second polar body extrusion several hours after ICSI? METHODS: We performed retrospective cohort study between October 2016 and September 2019, targeting 2891 oocytes in 843 cycles when ICSI was performed. We performed ROA with calcium ionophore on 395 of the 475 oocytes with no second polar extrusion 2.5-6 h after ICSI. RESULTS: The normal fertilization rate of ROA oocytes was significantly higher than non-ROA oocytes (65.8% vs 6.7%, P < 0.001). The blastocyst development rate in ROA oocytes was significantly lower than spontaneously activated oocytes (48.9% vs 67.2%, P < 0.001). The ROA oocyte implantation rate did not significantly differ from the spontaneously activated oocytes (36.0% vs 41.2%). We observed no differences in the implantation rates and blastocyst development rates over the 2.5-6 h from ICSI until ROA. CONCLUSION: Early ROA is effective, and the optimal timing appears to be 2.5-6 h after ICSI.

A gain-of-function mutation of plastidic invertase alters nuclear gene expression with sucrose treatment partially via GENOMES UNCOUPLED1-mediated signaling.

Plastid gene expression (PGE) is one of the signals that regulate the expression of photosynthesis-associated nuclear genes (PhANGs) via GENOMES UNCOUPLED1 (GUN1)-dependent retrograde signaling. We recently isolated Arabidopsis sugar-inducible cotyledon yellow-192 (sicy-192), a gain-of-function mutant of plastidic invertase, and showed that following the treatment of this mutant with sucrose, the expression of PhANGs as well as PGE decreased, suggesting that the sicy-192 mutation activates a PGE-evoked and GUN1-mediated retrograde pathway. To clarify the relationship between the sicy-192 mutation, PGE, and GUN1-mediated pathway, plastid and nuclear gene expression in a double mutant of sicy-192 and gun1-101, a null mutant of GUN1 was studied. Plastid-encoded RNA polymerase (PEP)-dependent PGE was markedly suppressed in the sicy-192 mutant by the sucrose treatment, but the suppression as well as cotyledon yellow phenotype was not mitigated by GUN1 disruption. Microarray analysis revealed that the altered expression of nuclear genes such as PhANG in the sucrose-treated sicy-192 mutant was largely dependent on GUN1. The present findings demonstrated that the sicy-192 mutation alters nuclear gene expression with sucrose treatment via GUN1, which is possibly followed by inhibiting PEP-dependent PGE, providing a new insight into the role of plastid sugar metabolism in nuclear gene expression.

Sequential changes in rat femoral artery blood flow and tissue degeneration after exposure to high-intensity focused ultrasound.

PURPOSE: The purpose of this study was to investigate the sequential changes in rat artery blood flow and tissue degeneration after exposure to high-intensity focused ultrasound (HIFU) in vivo. METHODS: HIFU was applied through the skin to the femoral artery of Sprague-Dawley rats. The peak intensities used were 530, 1080, 2750, and 4300 W/cm(2). After exposure, we measured the peak systolic velocity (PSV) in the artery every 1 min until the velocity stabilized. The vessel was resected and examined histologically 7 days after exposure. RESULTS: PSV was not significantly affected by HIFU exposure at 530 W/cm(2). PSV increased immediately after HIFU exposure at intensities of 1080 and 2750 W/cm(2). PSV after HIFU exposure at 1080 W/cm(2) fell to the control level within minutes; however, PSV increased immediately after HIFU exposure at 2750 W/cm(2) and then decreased slowly but remained at a higher level than the control for 15 min. On HIFU exposure at 4300 W/cm(2), the target artery was completely occluded. Histological studies 7 days after HIFU exposure demonstrated that exposure at 530 and 1080 W/cm(2) induced vacuolar degeneration in the tunica media of the femoral artery in rats; exposure to HIFU at 2750 and 4300 W/cm(2) resulted in strong necrotic degeneration in the tunica media. These histological changes were more marked than those found immediately after HIFU exposure. Organized thrombus formation was observed only for HIFU exposure at 4300 W/cm(2). CONCLUSION: Sequential changes in arterial blood flow after HIFU exposure vary with the intensity, and the histological changes in arterial tissue progress over time. These phenomena should be considered when HIFU is clinically applied to achieve arterial occlusion.