Dae Hwan Ko's research while affiliated with Gyeongsang National University and other places

... The blastocyst diameter at day 8 of culture, including zona pellucida thickness and cytoplasm diameter, was measured using Image J software [31]. ...

... ET is an invasive procedure. And some studies have suggested that invasive intrauterine operations or the manipulation of the genital tract could induce the release of prostaglandins resulting in uterine contractions 31,33,34 . Then, the embryo was prevented from implanting in the uterine cavity. ...

... Pregnancy rates with this technique have exceeded 55% in large-scale trials (Hasler et al., 1995;Nibart and Humblot, 1997). However, for vitrification there are many variations in protocols (Ishimori et al., 1993;Park et al., 1999;Vajta et al., 1999;Kim et al., 2004;Vajta and Nagy, 2006). Vitrification of in vitro-derived embryos results in highly variable pregnancy rates after transfer; the reported range is 23-50% of transferred embryos, but most of studies involved small numbers of embryos (Kuwayama et al., 1992;Tachikawa et al., 1993;Agca et al., 1994;Wurth et al., 1994;Delval et al., 1996;Holm et al., 1996). ...

... The sperm samples were retrieved by flushing PBS through the vas deference, followed by the collection of sperm from the cauda epididymis, as described earlier (Sahoo et al. 2021). The motile spermatozoa were purified by the Swim-up in Sp-TALP media for 30 min (Gupta et al. 2013). The sperm pellet was collected by centrifugation at 800 g for 10 min. ...

... For prolific livestock species, the main handicap of vitrification is the low number of embryos that commercial devices can hold transmission [3,5,6]. Although attempts have been made to generate systems that allow cryopreservation of large numbers of embryos, such as hollow fiber [7] or the easily accessible paper container method [8], commercial, large holding capacity devices for minimum volume cooling vitrification of oocytes or embryos are non-existent. For rabbits, however, using the French straw device (without limitation on the number of embryos to be stored by device) provides an acceptable offspring production efficiency calculated as the ratio of the number of birth kits to the number of embryos transferred (ranging from 25% to 65%, [9]), while in pigs, when using the open pulled straw (OPS) method (from five to seven embryos by device) a lower offspring production efficiency has been reported (ranging from 7.1% to 23%, [9,10]. ...