• Clinical and Experimental Reproductive Medicine
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• v.12 no.1
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• pp.83-98
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• 1985

In order to study the mechanism of follicular atresia, the follicles of the porcine ovary were isolated according to the presence or absence of the corpus luteum and their size, and then classified to the normal? or atretic?follicle on the morphological observation such as the transparency, the vascularization of follicle, the nuclear phase of oocyte, and the homogeneity of the granulosa cell layer. The viability of granulosa cells was examined. The concentrations of progesterone ($P_4$), testosterone (T), and estradiol-17 beta ($E_2$) in each follicular fluid were estimated by the radioimmunoassay. The viability of granulosa cells in the atretic follicle was much lower than that of the normal one. The concentration of each steroid hormone increased as the follicular size was increased, was not different in quantity between the normal- and the atretic follicle of which diameter was below 3mm, and were much higher in the atretic follicle than those in the normal one of which diameter was above 7mm. The ratio of the concentration of E2 to T in the large atretic follicle valued higher than that in the normal one, but smaller in the small and medium atretic follicle than that in the normal one. The present study suggests that the mechanism of atresia of the large follicle may be different from that of the small and the medium follicle and that the amount of steroid hormones regarded as the one of the criteria for the atretic follicles.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.1
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• pp.41-47
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• 2009

The seasonal reproductive cycle of Gomphina melanaegis collected in the coastal area of Jumunjin, between April 2006 and March 2007, was analyzed. Maturation cycle parameters such as the gonad index (GI), ovarian egg diameter, frequency of developmental stages, protein content, and RNA/DNA variation in the gonads were analyzed monthly for the 40 samples. According to the indices from histological sections, the frequency of gonad developmental stages, and the oocyte diameter, this clam has a long-term partial spawning pattern from March to October. However, GI and nucleic acid values showed that the mature stage is from March to July and that the main spawning season is August. The peak RNA and DNA contents were good indicators of sexual maturation in females and males, respectively. The variation in protein content corresponded with the RNA/DNA ratios.

• Journal of Embryo Transfer
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• v.19 no.2
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• pp.185-189
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• 2004

The purpose of this study was to determine the possibility of in vitro maturation of tiger oocytes. Immature oocytes were recovered from a pair of ovaries. A total of 78 oocytes was collected, of which forty three were classified as good oocytes with compact cumulus cells and uniform cytoplasm. Forty three COCs were in vitro matured at $39^{\circ}C$, 5% CO2 in air atmosphere for 48 h in a IVM medium (TCM-199 supplement with 10% FBS, 0.6 mM cysteine, 0.2 mM pyruvic acid and 10 IU/mL HMG). Experiment I: the morphologic evaluation was conducted by measuring the diameter of oocytes with or without ZP, the thickness of ZP and the diameter of cytoplasm by microeyepiece at the same magnification (${\times}$100). Experiment II: the evaluation of meiotic development was conducted of the nuclear development stage of tiger oocytes. The results were summarized as follows: 1. The diameter of tiger oocytes $(176.5\pm6.1{\mu}m)$ with ZP was significantly (p<0.05) bigger than that of bovine oocytes $(150.7\pm4.9{\mu}m).$ The ZP thickness of tiger oocytes $(20.4\pm2.9{\mu}m)$ was significantly (p<0.05) bigger than that of bovine oocytes $(12.0\pm2.6{\mu}m;$ p<0.05). However, there was no significant difference in the diameter of cytoplasm (without ZP) between tiger $(122.1\pm9.7{\mu}m)$ and bovine oocytes $(118.7\pm7.5{\mu}m).$ 2. The rates of meiotic development of tiger oocytes were achieved GV (12.5 %) and MII (50.0%), respectively. These results indicated that tiger oocytes could be developed to MII in in vitro culture system.

• Journal of Aquaculture
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• v.15 no.1
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• pp.43-48
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• 2002

We investigated the gonadosomatic index (GSI), germ cell development, reproductive cycle of the Afriean lungfish Protorierus annecteus (Owen) by histological observations and morphometric data. Samples were collected from the river Orie and its flood of Nigeria, from January to December 2000. The fish is dioecious and oviparous. Monthly changes in the gonadosomatic index (GSI) showed a similar pattern to change in the mean oocyte diameter and the reproductive cycle. The reproductive period occurred from March to July-August; the spawning period was once a year between truly and August, and the main spawning occurred in August when active and voracious feeding occurred during the rainy season. In the resting (dormant) stage after spawning, fish stopped feeding and aestivated during the dry season from December to February. The reproductive cycle of the species can be divided into five successive stages, quiescent stage (March to April), developing/maturing stage (April to lune), ripe/spawning stage (July to August), post-spawning stage (September to November), and resting (dormant) stage (December to February).

• Reproductive and Developmental Biology
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• v.28 no.4
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• pp.235-240
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• 2004

In vitro maturation of denuded porcine immature oocytes can be enhanced by co-incubation with spermatozoa even before fertilization. This study was to determine whether the addition of spermatozoa into the culture medium could influence the nuclear maturation of porcine cumulus-enclosed germinal vesicle (GV) oocytes. Cumulus-oocyte complexes (COCs) were collected from follicles of 3- to 5-mm diameter. Porcine COCs were cultured in tissue culture medium containing spermatozoa. After 48 h culture, oocytes were examined for evidence of GV breakdown, metaphase I, anaphase-telophase I, and metaphase II. The proportion of oocytes reaching at metaphase II was significantly (P < 0.05) increased in the oocytes cultured in media containing spermatozoa compared to those in media without spermatozoa (52.3% vs 12.5%). No difference in the percentage of metaphase II was observed among the different periods of spermatozoa exposure and among the spermatozoa from different species. The proportion of oocytes reaching metaphase II was significantly different between high and low concentrations of spermatozoa. The present study suggests that manunalian spermatozoa contain a substance(s) that improves nuclear in vitro maturation of porcine cumulus-enclosed GV oocytes. Enhancing effect of spermatozoa for in vitro maturation of oocytes is a highly dose-dependent.

• Korean Journal of Veterinary Research
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• v.38 no.1
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• pp.209-216
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• 1998

The purpose of present study is to improve the efficiency of fusion and the developmental rates of nuclear transplanted embryos to produce genetically identical twins from Korean native cattle. The diameter of aspirated follicles had no significant effect on the recovery rates of oocytes collected by ovum pick-up technique. The fusion rates of nuclear transplanted embryos were significantly higher in 50 and $100{\mu}s$ DC duration groups(73.3 and 72.0% ; respectively) than that in $30{\mu}s$ group(55.6% ; p<0.05). The cleavage rates of nuclear transplanted embryos appeared to be significantly higher in donor nuclei derived from in vivo (65.0%) than in those from in vitro (50.5% ; p<0.01), but the developmental rates to morulae and blastocysts were not significantly different between them(13.7 vs 10.9%, respectively).

• Reproductive and Developmental Biology
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• v.34 no.3
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• pp.223-227
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• 2010

These study was carried out to investigate the effects of the recovery time, diameter of oocytes on in vitro fertilization or intracytoplasmic sperm injection (ICSI). The in vitro maturation rates to MII stage of oocytes recovered at the inactive, follicular and luteal stages matured for 72 h were $1.4{\pm}0.0%$, $43.4{\pm}3.2%$ and $10.8{\pm}2.7%$, respectively. The fertilization rates of in vitro cultured oocytes recovered from ovaries at the in active, follicular and luteal stages were $0.0{\pm}0.0%$, $15.7{\pm}3.4%$ and $7.6{\pm}3.5%$, respectively. The in vitro maturation rate of oocytes recovered from ovaries at the follicular stage of the reproductive cycle was significantly higher than those at the inactive and luteal stages (p<0.05). The penetration rate determined that the percentages of oocytes with diameters in the < $100\;{\mu}m$, 100 to $100\;{\mu}m$ and 110 to $120\;{\mu}m$ ranges were $17.5{\pm}4.7%$, $43.9{\pm}4.5%$, $21.3{\pm}3.4%$, respectively. The penetration rate of oocytes with diameters between 100 to $100\;{\mu}m$ was significantly higher than that of oocytes whose diameters were < $100\;{\mu}m$ and $110{\sim}120\;{\mu}m$ (p<0.05). The penetration rate of oocytes determined that the percentages of ovaries with diameters between 1 to 5 mm and 6 to 10 mm were $32.9{\pm}3.2%$ and $17.5{\pm}3.7%$, respectively. Thus, the diameters of the ovaries were significantly higher at 1 to 5 mm (p<0.05). A total of 264 oocytes were fixed and stained after co-incubation with sperm, of which 72 had identifiable nuclear material. After in vitro fertilization for 20 hrs, 27.3% of oocytes were penetrated by spermatozoas. Oocytes were fixed and stained after ICSI, of which 38 oocytes contained identifiable nuclear material. After in vitro fertilization and ICSI for 20 hrs, to 27.3% and 67.9% of oocytes were penetrated by spermatozoas. The in vitro fertilization rates by ICSI was significantly higher than that in vitro fertilization method (p<0.05).

• Journal of Embryo Transfer
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• v.20 no.1
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• pp.63-69
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• 2005

This study were carried out to evaluate the possibility of nuclear progression of canine immature oocytes, of which was cultured in a reproductive tract, such as oviduct, ovarian bursa and uterus of estrus bitch for 4, 5 and 6 days following immediately collection. Cumulus intact oocytes(COC) fore collected from domestic dog following ovariohysterectomy at local veterinary clinics. In Exp. 1, COCs $of>110\;{\mu}m$ diameter were selected and cultured in vitro at $39^{\circ}C$, $5\%\;CO\_{2} $ in air atmosphere. The nuclear progression of canine oocytes checked at 24, 48 or 72 h after in vitro maturation. There was not increased the nuclear progression to the M II stage depending on culture periods at 24, 48 and 72h $(1.3\%,\;3.7\%\;and\;4.7\%)$. In Exp. 2, to evaluate of nuclear progression of immature oocytes, collected or in vitro cultured oocytes were transfer into a canine reproductive tract (oviduct, ovarian bursa and uterus). The recovery rates of canine oocytes from a reproductive tract after 4 days $(33.7\%)$ in vivo culture were significantly higher than those 5 $(17.7\%)$ 6 day $(3.4\%)$ (P<0.05). The survival rates of collected oocytes after 4 days $(60.0\%)$ were also significantly higher than those of 5 days $(30.2\%)$ and 6 days $(38.9\%)$ (P<0.05). The meiotic resumption rates of canine oocytes were not significantly difference among the culture periods at 4 days $(5.9\%)$, 5 days $(0.0\%)$ and 6 days $(0.0\%)$. These results show that the nuclear progression of canine immature oocytes from in in vivo culture was not affect the nuclear resumption of oocytes.

• Development and Reproduction
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• v.12 no.1
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• pp.107-112
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• 2008

To investigate the $C_{21}$-steroids produced from maturating oocytes in the longchin goby, Chasmichthys dolichognathus, the oocytes ($0.74{\sim}0.97\;mm$) were incubated with radiolabeled $17{\alpha}$-hydroxyprogesterone ($^3H-17{\alpha}OHP$) for 24 hours. The resulting metabolites were analyzed by thin layer chromatography and identified by gas chromatography-mass spectrometry. Two $C_{21}$-steroids, $17{\alpha}$-hydroxy, $20{\alpha}$-dihydroprogesterone ($17{\alpha}20{\alpha}P$) and $17{\alpha}$-hydroxy, $20{\beta}$-dihydroprogesterone ($17{\alpha}20{\beta}P$), were converted from $^3H-17{\alpha}OHP$ in the maturing oocytes. These two main metabolites were detected at 0.80 mm diameter oocytes or greater. In addition, the effects of these metabolites on in vitro germinal vesicle breakdown (GVBD) were tested. The sensitivity of oocytes to the induction of GVBD was greater at $17{\alpha}20{\beta}P$ than $17{\alpha}20{\alpha}P$. This result showed that $17{\alpha}20{\beta}P$ is a major maturation inducing steroid (MIS) in longchin goby, suggesting $17{\alpha}20{\alpha}P$ may play a role in regulating the oocyte maturation process.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.5
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• pp.612-616
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• 2004

This study was carried out to compare the semen characteristics, frozen-thawed sperm viability and testosterone concentration and in vitro fertilization (IVF) and development of in vitro matured pig oocytes between two Yorkshire boars. Semen and blood samples were collected once per week from October to November 2002 from two adult Yorkshire boars at 18 months of age with 170 kg body weight. Sperm were deep frozen in 5 ml maxi-straws with lactose-egg yolk and N-acetyl-D-glucosamine (LEN) diluent and stored in liquid nitrogen. Blood samples were obtained at 10 a.m. by inserting a 21 gauge, hypodermic needle attached to 10 ml syringe into surface veins in the ear. The concentration of testosterone was determined by Competitive Enzyme Immunoassay. Ovaries were collected from prepubertal gilts at a local slaughter house. Cumulus oocyte complexes were aspirated from antral follicles (3 to 6 mm in diameter). The medium used for oocyte maturation was modified TCM 199. After about 22 h of culture, oocytes were cultured without cysteamine and hormones for 22 h at $38.5^{\circ}C$, 5% $CO_2$ in air. For IVF, one frozen 5 ml straw was thawed at $52^{\circ}C$in 40 sec and was diluted with 20 ml Beltsville thawing solution at room temperature. Sperm were washed 2 times in mTLP-PVA and inseminated without preincubation after thawing. Oocytes were inseminated with $2{\times}10^7$/ml sperm concentration. Oocytes were coincubated for 6 h in 500 ${\mu}$l mTBM fertilization medium. At 6 h after IVF, oocytes were transferred into 500 ${\mu}$l NCSU-23 culture medium for further culture of 48 and 144 h. There were no significant differences in the semen volume, motility, normal acrosome morphology and sperm concentration of raw semen between A and B of Yorkshire boar. However, motility and normal acrosome of boar A were higher than those of boar B at 0.5, 2, 3, 4, 5 and 6 h incubations of frozen-thawed sperm. Testosterone concentration (3.75 ng/ml) of boar A was higher than that (2.34 ng/ml) of boar B. The rate of blastocyst formation (15.1%) of boar A was higher than that (10.4%) of boar B. In conclusion, serum testosterone concentration of boar showed very important role for the frozen-thawed sperm viability and the blastocyst formation of pig oocytes matured in vitro.