The Experts below are selected from a list of 13299 Experts worldwide ranked by ideXlab platform
Colin D. Matthews - One of the best experts on this subject based on the ideXlab platform.
-
preliminary observations on polar body extrusion and pronuclear formation in human oocytes using time lapse video Cinematography
Human Reproduction, 1997Co-Authors: Dianna Payne, Michael Franciscus Barry, Sean P. Flaherty, Colin D. MatthewsAbstract:In this study, we have used time-lapse video Cinematography to study fertilization in 50 human oocytes that had undergone intracytoplasmic sperm injection (ICSI). Time-lapse recording commenced shortly after ICSI and proceeded for 17-20 h. Oocytes were cultured in an environmental chamber which was maintained under standard culture conditions. Overall, 38 oocytes (76%) were fertilized normally, and the fertilization rate and embryo quality were not significantly different from 487 sibling oocytes cultured in a conventional incubator. Normal fertilization followed a defined course of events, although the timing of these events varied markedly between oocytes. In 35 of the 38 fertilized oocytes (92%), there were circular waves of granulation within the ooplasm which had a periodicity of 20-53 min. The sperm head decondensed during this granulation phase. The second polar body was then extruded, and this was followed by the central formation of the male pronucleus. The female pronucleus formed in the cytoplasm adjacent to the second polar body at the same time as, or slightly after, the male pronucleus, and was subsequently drawn towards the male pronucleus until the two abutted. Both pronuclei then increased in size, the nucleoli moved around within the pronuclei and some nucleoli coalesced. During pronuclear growth, the organelles contracted from the cortex towards the centre of the oocyte, leaving a clear cortical zone. The oocyte decreased in diameter from 112 to 106 μm (P < 0.0001) during the course of the observation period. The female pronucleus was significantly smaller in diameter than the male pronucleus (24.1 and 22.4 μm respectively, P = 0.008) and contained fewer nucleoli (4.2 and 7.0 respectively, P < 0.0001). After time-lapse recording, oocytes were cultured for 48 h prior to embryo transfer or cryopreservation. Embryo quality was related to fertilization events and periodicity of the cytoplasmic wave, and it was found that good quality embryos arose from oocytes that had more uniform timing from injection to pronuclear abuttal and tended to have a longer cytoplasmic wave. In conclusion, we have shown that time-lapse video Cinematography is an excellent tool for studying fertilization and early embryo development, and have demonstrated that human fertilization comprises numerous complex dynamic events.
Kazuo Maeda - One of the best experts on this subject based on the ideXlab platform.
-
time lapse Cinematography of dynamic changes occurring during in vitro development of human embryos
American Journal of Obstetrics and Gynecology, 2008Co-Authors: Y Mio, Kazuo MaedaAbstract:Objective The purpose of this study was to clarify developmental changes of early human embryos by using time-lapse Cinematography (TLC). Study Design For human ova, fertilization and cleavage, development of the blastocyst, and hatching, as well as consequent changes were repeatedly photographed at intervals of 5-6 days by using an inverse microscope under stabilized temperature and pH. Photographs were taken at 30 frames per second and the movies were studied. Results Cinematography has increased our understanding of the morphologic mechanisms of fertilization, development, and behavior of early human embryos, and has identified the increased risk of monozygotic twin pregnancy based on prolonged incubation in vitro to the blastocyst stage. Conclusion Using TLC, we observed the fertilization of an ovum by a single spermatozoon, followed by early cleavages, formation of the morula, blastocyst hatching, changes in the embryonic plates, and the development of monozygotic twins from the incubated blastocysts.
öttche Pete - One of the best experts on this subject based on the ideXlab platform.
-
In vivo fluoroscopic kinematography of cranio-caudal stifle stability after tibial tuberosity advancement (TTA): a retrospective case series of 10 stifles
Open Veterinary Journal, 2018Co-Authors: Schwede Maartje, Rey Janna, öttche PeteAbstract:It was the aim of the study to determine retrospectively cranio-caudal stifle instability following TTA (tibial tuberosity advancement) using fluoroscopic kinematography. Ten stifles (eight dogs, mean body weight 27.3 kg) with complete rupture of the cranial cruciate ligament and a mean follow-up of 12.8 weeks (5.4 - 28.4 weeks) after TTA underwent latero-lateral, uniplanar fluoroscopic kinematography while walking on a treadmill. Immediately before TTA, each stifle was explored arthroscopically and in the case of a longitudinal or bucket-handle tear of the caudal horn of the medial meniscus the unstable axial portion was resected. The high-speed fluoroscopic video sequences obtained were inspected visually for femoro-tibial translation (cranial drawer). The influence of postoperative patellar tendong angle (PTA), cage size and meniscal surgery on stifle stability was analyzed using logistic regression analysis. In three stifles, resection of unstable meniscal tissue was necessary. Fluoroscopically, nine out of ten stifles showed cranio-caudal instability. Three stifles were potentially overcorrected (post PTA < 90°), seven potentially undercorrected (post PTA > 90°). None of the three parameters analyzed had a significant influence on postoperative in vivo stability (p=0.0988). In conclusion, it appears that inadequate cranialization of the tibia tuberosity might be an expected result of the TTA procedure, as well as persistent cranio-caudal instability during walking. However, instability cannot solely be attributed to insufficient cranialization because three out of nine unstable stifles were sufficiently or even overcorrected (PTA ≤ 90°). Further in vivo studies are needed to resolve these conflicting findings.Keywords: Cruciate ligament rupture, Dog, Fluoroscopy, Joint stability, Kinematic
-
a retrospective case series of 10 stifles
2018Co-Authors: Schwede Maartje, Rey Janna, öttche PeteAbstract:It was the aim of the study to determine retrospectively cranio-caudal stifle instability following TTA (tibial tuberosity advancement) using fluoroscopic kinematography. Ten stifles (eight dogs, mean body weight 27.3 kg) with complete rupture of the cranial cruciate ligament and a mean follow-up of 12.8 weeks (5.4 - 28.4 weeks) after TTA underwent latero-lateral, uniplanar fluoroscopic kinematography while walking on a treadmill. Immediately before TTA, each stifle was explored arthroscopically and in the case of a longitudinal or bucket-handle tear of the caudal horn of the medial meniscus the unstable axial portion was resected. The high-speed fluoroscopic video sequences obtained were inspected visually for femoro-tibial translation (cranial drawer). The influence of postoperative patellar tendong angle (PTA), cage size and meniscal surgery on stifle stability was analyzed using logistic regression analysis. In three stifles, resection of unstable meniscal tissue was necessary. Fluoroscopically, nine out of ten stifles showed cranio-caudal instability. Three stifles were potentially overcorrected (post PTA 90°). None of the three parameters analyzed had a significant influence on postoperative in vivo stability (p=0.0988). In conclusion, it appears that inadequate cranialization of the tibia tuberosity might be an expected result of the TTA procedure, as well as persistent cranio-caudal instability during walking. However, instability cannot solely be attributed to insufficient cranialization because three out of nine unstable stifles were sufficiently or even overcorrected (PTA ≤ 90°). Further in vivo studies are needed to resolve these conflicting findings
Dianna Payne - One of the best experts on this subject based on the ideXlab platform.
-
preliminary observations on polar body extrusion and pronuclear formation in human oocytes using time lapse video Cinematography
Human Reproduction, 1997Co-Authors: Dianna Payne, Michael Franciscus Barry, Sean P. Flaherty, Colin D. MatthewsAbstract:In this study, we have used time-lapse video Cinematography to study fertilization in 50 human oocytes that had undergone intracytoplasmic sperm injection (ICSI). Time-lapse recording commenced shortly after ICSI and proceeded for 17-20 h. Oocytes were cultured in an environmental chamber which was maintained under standard culture conditions. Overall, 38 oocytes (76%) were fertilized normally, and the fertilization rate and embryo quality were not significantly different from 487 sibling oocytes cultured in a conventional incubator. Normal fertilization followed a defined course of events, although the timing of these events varied markedly between oocytes. In 35 of the 38 fertilized oocytes (92%), there were circular waves of granulation within the ooplasm which had a periodicity of 20-53 min. The sperm head decondensed during this granulation phase. The second polar body was then extruded, and this was followed by the central formation of the male pronucleus. The female pronucleus formed in the cytoplasm adjacent to the second polar body at the same time as, or slightly after, the male pronucleus, and was subsequently drawn towards the male pronucleus until the two abutted. Both pronuclei then increased in size, the nucleoli moved around within the pronuclei and some nucleoli coalesced. During pronuclear growth, the organelles contracted from the cortex towards the centre of the oocyte, leaving a clear cortical zone. The oocyte decreased in diameter from 112 to 106 μm (P < 0.0001) during the course of the observation period. The female pronucleus was significantly smaller in diameter than the male pronucleus (24.1 and 22.4 μm respectively, P = 0.008) and contained fewer nucleoli (4.2 and 7.0 respectively, P < 0.0001). After time-lapse recording, oocytes were cultured for 48 h prior to embryo transfer or cryopreservation. Embryo quality was related to fertilization events and periodicity of the cytoplasmic wave, and it was found that good quality embryos arose from oocytes that had more uniform timing from injection to pronuclear abuttal and tended to have a longer cytoplasmic wave. In conclusion, we have shown that time-lapse video Cinematography is an excellent tool for studying fertilization and early embryo development, and have demonstrated that human fertilization comprises numerous complex dynamic events.
Otmar Hilliges - One of the best experts on this subject based on the ideXlab platform.
-
real time planning for automated multi view drone Cinematography
ACM Transactions on Graphics, 2017Co-Authors: Tobias Nageli, Lukas Meier, Alexander Domahidi, Javier Alonsomora, Otmar HilligesAbstract:We propose a method for automated aerial videography in dynamic and cluttered environments. An online receding horizon optimization formulation facilitates the planning process for novices and experts alike. The algorithm takes high-level plans as input, which we dub virtual rails, alongside interactively defined aesthetic framing objectives and jointly solves for 3D quadcopter motion plans and associated velocities. The method generates control inputs subject to constraints of a non-linear quadrotor model and dynamic constraints imposed by actors moving in an a priori unknown way. The output plans are physically feasible, for the horizon length, and we apply the resulting control inputs directly at each time-step, without requiring a separate trajectory tracking algorithm. The online nature of the method enables incorporation of feedback into the planning and control loop, makes the algorithm robust to disturbances. Furthermore, we extend the method to include coordination between multiple drones to enable dynamic multi-view shots, typical for action sequences and live TV coverage. The algorithm runs in real-time on standard hardware and computes motion plans for several drones in the order of milliseconds. Finally, we evaluate the approach qualitatively with a number of challenging shots, involving multiple drones and actors and qualitatively characterize the computational performance experimentally.