• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.319-327
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• 2009

Follicular fluid meiosis-activating sterol (FF-MAS) has been suggested as a positive factor which could improve the oocyte quality and subsequent embryo development after in vitro fertilization. However, FF-MAS is a highly lipophilic substance and is hard to detect in studying the relationship between MAS and quality of oocyte maturation. The present study focused on the expression of lanosterol 14${\alpha}$-demethylase (LDM), a key enzyme that converts lanosterol to FF-MAS, on mouse oocyte maturation and its potency on development. LDM expression was strong in gonadotropin-primed germinal vesicle stage oocytes, weak after germinal vesicle breakdown (GVBD), and then strong in MII stage oocytes. The LDM-specific inhibitor azalanstat significantly inhibited oocyte fertilization (from 79.4% to 68.3%, p<0.05). Also, azalanstat (5 to 50 ${\mu}M$) decreased the percentage of blastocyst development dosedependently (from 78.7% to 23.4%, p<0.05). The specific inhibition of sterol ${\Delta}14$-reductase and ${\Delta}7$-reductase by AY9944 accumulates FF-MAS and could increase blastocyst development rates. Additionally, in the AY9944 group, the rate of inner cell mass (ICM)/ total cells was similar to that of in vivo development, but the rate was significantly decreased in azalanstat treatment. In conclusion, LDM, the key enzyme of FF-MAS production, may play an important role in fertilization and early development of the mouse embryo, especially in vitro.

• Clinical and Experimental Reproductive Medicine
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• v.42 no.3
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• pp.111-117
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• 2015

Objective: In order to increase the number of mature oocytes usable for intracytoplasmic sperm injection (ICSI), we aimed to investigate the effect of co-culturing granulosa cells (GCs) on human oocyte maturation in vitro, the fertilization rate, and embryo development. Methods: A total of 133 immature oocytes were retrieved and were randomly divided into two groups; oocytes that were cultured with GCs (group A) and oocytes that were cultured without GCs (group B). After in vitro maturation, only oocytes that displayed metaphase II (MII) underwent the ICSI procedure. The maturation and fertilization rates were analyzed, as well as the frequency of embryo development. Results: The mean age of the patients, their basal levels of follicle-stimulating hormone, and the number of oocytes recovered from the patients were all comparable between the two study groups. The number of oocytes that reached MII (mature oocytes) was 59 out of 70 (84.28%) in group A, compared to 41 out of 63 (65.07%) in group B (p=0.011). No significant difference between fertilization rates was found between the two study groups (p=0.702). The embryo development rate was higher in group A (33/59, 75%) than in group B (12/41, 42.85%; p=0.006). The proportion of highest-quality embryos and the blastocyst formation rate were significantly lower in group B than in group A (p=0.003 and p<0.001, respectively). Conclusion: The findings of the current study demonstrate that culturing immature human oocytes with GCs prior to ICSI improves the maturation rate and the likelihood of embryo development.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.2
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• pp.194-199
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• 2016

In an experiment conducted at the research field of the National Institute of Agricultural Science, we investigated the effects of mineral fertilizer and rice straw compost on exchangeable potassium and K balances, and rice grain yield under a rice single system. The treatments were no fertilization (No fert.), inorganic fertilization (N), inorganic fertilizer (N, P, K) plus rice straw compost at rates of 7.5, 15.0, 22.5, and $30.0ton\;ha^{-1}$ (NPKC7.5, NPKC15.0, NPKC22.5, and NPKC30.0, respectively). The inorganic fertilizers(N, P, K) were added with standard fertilizer application rate in which nitrogen (N), phosphate ($P_2O_5$), and potassium ($K_2O$) were applied with $75{\sim}150kg\;ha^{-1}$, $70{\sim}86kg\;ha^{-1}$, $75{\sim}86kg\;ha^{-1}$, respectively. Exchangeable potassium for NPKC15.0 NPKC22.5, and NPK30.0 treatments was higher by $0.05{\sim}0.19cmol_c\;kg^{-1}$ than that of NPKC7.5 treatment. Increasing levels of rice straw compost resulted in an increase in the K balance from - $19.9kg\;ha^{-1}yr^{-1}$ (No fert.) to $41.9kg\;ha^{-1}yr^{-1}$ at NPKC22.5 treatment and $62.9kg\;ha^{-1}$ at NPKC30.0 treatment. Continuous application of rice straw compost with NPK fertilizers affected significantly the rice grain yields. The result of the study imply that the application of more than $22.5ton\;ha^{-1}$ of rice straw compost with NPK fertilizers are recommended as the best fertilization practice for enhancement of crop production and K supplying power of soil in the continuous rice cropping system.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.2
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• pp.90-95
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• 2017

Objective: We investigated whether the insemination method (in vitro fertilization [IVF] or intracytoplasmic sperm injection [ICSI]) affected morphokinetic events and abnormal cleavage events in embryonic development. Methods: A total of 1,830 normal fertilized embryos were obtained from 272 IVF and ICSI cycles that underwent ovum retrieval culture using a time-lapse system (Embryoscope) from June 2013 to March 2015. All embryos were investigated by a detailed time-lapse analysis that measured the developmental events in the hours after IVF or ICSI insemination. Results: No significant differences were observed between the two groups regarding clinical outcomes (p>0.05). ICSI-derived embryos showed significantly faster morphokinetics than those derived from conventional IVF, from the time to pronuclear fading to the time to 6 cells (p<0.05). However, no significant differences were found from the time to 7 cells to the time to expanded blastocyst (p>0.05). There were no differences in abnormal cleavage events between the two groups (p>0.05); they showed the same rates of direct cleavage from 1 to 3 cells, 2 multinucleated cells, 2 uneven cells, and reverse cleavage. Conclusion: The morphokinetics of embryo development was found to vary between IVF- and ICSI-fertilized oocytes, at least until the 6-cell stage. However, these differences did not affect the clinical outcomes of the embryo. Additionally, no significant differences in abnormal cleavage events were found according to the fertilization method.

• Clinical and Experimental Reproductive Medicine
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• v.18 no.1
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• pp.13-21
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• 1991

To investigate the factors that affect the fertilization and cleavage rates of mature oocytes, 44 patients undergoing controlled ovarian hyperstimulation(COH) with FSH/hMG/hCG regimen for IVF - ET were analyzed. During follicular phase, serum LH levels were measured by radioimmunoassay and bioassay. Based on the mean follicular immunoactive LH(i-LH) and bioactive LH(b-LH) levels, patients were divided into 3 groups, respectively. There were no significant differences in basal serum FSH levels on menstrual cycle day 3, serum estradiol($E_2$) and progesterone ($P_4$) levels on the day of hCG administration, and the numbers of follicles aspirated and oocytes retrieved among groups. In relation to the mean follicular i-LH levels, the fertilization and cleavage rates of mature oocytes did not show a significant difference among groups. However, in groups with higher mean follicular b-LH levels, the fertilization and cleavage rates were reduced significantly. During late follicular phase, day-to-day variance in b-LH levels was not significant, but there was a significant difference among groups. There was no significant correlation between serum P. and b-LH levels. These data suggest that the fertilization and cleavage rates of mature oocytes are adversely affected by the raised mean follicular b-LH levels, and monitoring of serum b-LH levels is more useful in COH when compared with i-LH. It appears that the reduced rates are not due to the attenuated endogenous LH surge.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.3
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• pp.169-174
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• 1995

To investigate the effects of nitrogen(N) fertilization levels on the dry matter(DM) yield, nutrition yield, and N efficiency of forages in mixed sward of alfalfa-grasses, a field experiment arranged by randomized complete block design with five treatments(0, 70, 140, 210 and 280kg N/ha) was conducted at Livestock Experiment Station in Suwon, September, 1990 to February, 1993. During two years, average DM yields of forage increased as N fertilization level was increased, but no significant difference was found between DM 10,266kg of N 210kgha and DM 10,845kg of N 280kgha. Crude protein and energy productivity of forages increased as N fertilization level was increased, and the increasing degree was highest between N 140kg and 210kg/ha fertilization. With increasing N fertilization, mineral contents tended to decrease in P and K/Ca+ Mg equivalent ratios, to increase in Mg, but not to be regular in the other elements. Efficiency of N was highest at N 210kg/ha fertilization, which produced DM 21.6kg, net energy lactation 129.3 MJ, starch equivalent 12.3kStE and total digestible nutrients 14.5kg per Ikg N.

• Clinical and Experimental Reproductive Medicine
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• v.19 no.1
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• pp.57-64
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• 1992

The present study was undertaken to clarify the role of TEST-Yolk Buffer(TYB) as a factor for the improvement of human sperm fertility potential. We examined the effects of low temperature capacitation using TYB on sperm motility (%), motility pattern, normal morphology, true acrosome reaction, sperm penetration assay and human in vitro fertilization. Comparing the TYB method and swim-up method, the sperm motility(%) of selected sperm was not significantly different, but statistically significant differences were found in curvilinear velocity, linearity, lateral head displacement, normal morphology(%) and true acrosome reaction(%)(p<0.05). Results obtained from the sperm penetration assay demonstrated that the penetration index and penetration rate were increased significantly(p<0.05) when the spermatozoa were incubated in TYB, as compared with swim-up method. And fertilization of intact human oocytes was more succesful when spermatozoa were pretreated with TYB at $4^{\circ}C$ for 48 hours as compared with swim-up method. Our results show that TYB method have advantages in terms of enhancement of sperm hyperactivation, increased true acrosome reaction, increased ability to penetrate zona-free hamster ova and augmented fertilization of human oocytes, suggesting that TYB is superior in its ability to preserve sperm motility and fertilizing ability.

• Clinical and Experimental Reproductive Medicine
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• v.23 no.1
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• pp.51-59
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• 1996

Controlled Ovarian hyperstimulation(COH) is generally used to obtain synchronous high quality oocytes in in vitro fertilization-embryo transfer(IVF-ET). Many investigators have studied the relationship between serum hormone levels and outcomes of IVF-ET because there is no accurate estimation method of oocyte quality. Early premature luteinization of follicles before oocyte retrieval is the most troublesome problem in COH for IVF-ET. Gonadotropin-releasing hormone agonists(GnRH-a) are used as adjuncts with gonadotropins for COH in patients undergoing in IVF. The possible benefits of GnRH-a pretreatment include improving oocyte quality, allowing a more synchronous cohort of follicles to be recruited, and preventing premature lueinization hormone surges. In COH of IVF cycles, we investigated whether an elevated progesterone(P4) level on the day of human chorionic gonadotropin(hCG) administration indicates premature luteinization and is associated with a lower fertilization rate. Many investigators have studied that the lower fertilization rates seen in patients with elevated P4 levels might result from an adverse effect of P4 on the oocytes. We hypothesizes that serum P4 levels around the day of hCG may be helpful prediction of out come in IVF-ET cycles. Success rates after COH of IVF-ET cycles are dependent upon many variable factors. Follicular factors including the number of follicles, follicular diameters and especially serum estradiol(E2) levels as an indirect measurement of follicular function and guality have been thought to influence the outcomes of IVF-ET. To assess whether serum P4 and E2 levels affect the fertilization and pregnancy rate, we reviewed the stimulation cycles of 113 patients (119 cycles) undergoing IVF-ET with short protocol with GnRH-a, from March 1993 to August 1994 retrospectively. The serum P4 and E2 levels were compared on the day of hCG in the pregnant group, 45 patients(47 cycles) and in the non-pregnant group, 68 patients (72 cycles) respectively. The serum E2 level in non-pregnant group was $1367{\pm}875.8$ pg/ml which was significantly lower than that of pregnant group, $1643{\pm}987.9$ pg/ml( p< 0.01 ). And the serum P4 level in non-pregnant group was $2.1{\pm}1.4$ ng/ml which was significantly higher than that of pregnant group, $1.0{\pm}0.7$ ng/ml( p< 0.001 ). The fertilization rate was $61.3{\pm}21.3%$ in pregnant group which was higher than that of non-pregnant group, $41.1{\pm}20.2%$ (p< 0.01). We suggest that the serum levels of P4 and E2 on the day of hCG administration are additional parameters that predict the outcomes of IVF-ET cycles.

• Korean Journal of Agricultural Science
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• v.23 no.2
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• pp.206-211
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• 1996

This study was conducted to investigate the effects of medium and cumulus cell on in vitro fertilization of porcine follicular oocytes. The results obtained are as follows ; 1. The normal fertilization rates of in vitro matured follicular oocytes cultured in 00, mT ALP and TCM-HEPES medium were 14.0~24.3%, 30.8~32.7% and 21.4~23.9%, respectively. These data indicated that the optimal medium for fertilization of porcine oocytes in vitro was the mTALP medium 2. The normal fertilization rates of epididymal sperm were 24.3%(80), 30.8%(mTALP) and 23.9%(TCM-HEPES), and those of ejaculated sperm were 14.0%(B0), 32.7%(mTALP) and 21.4%(TCM-HEPES). 3. The sperm penetration rates of cumulus-enclosed and cumulus-free oocytes on in vitro fertilization were 54.0% and 72.0%. The normal fertilization rates of cumulus-enclosed and cumulus-free oocytes were 11.9% and 21.5%. The normal fertilization rate of cumulus-enclosed oocytes was significantly(P<0.05) higher than that of cumulus-free oocytes.

• Clinical and Experimental Reproductive Medicine
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• v.42 no.2
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• pp.67-71
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• 2015

Objective: Elevated serum progesterone (P) levels on triggering day have been known to affect the pregnancy rate of in vitro fertilization (IVF). This study aimed to identify the possible factors influencing serum P levels on triggering day in stimulated IVF cycles. Methods: Three hundred and thirty consecutive fresh IVF cycles were included in the study. All cycles were first attempts and were performed in a single infertility center. The indications for IVF were male factor infertility (n=114), ovulatory infertility (n=84), endometriosis (n=61), tubal infertility (n=59), unexplained infertility (n=41), and uterine factor infertility (n=39). A luteal long protocol of a gonadotropin-releasing hormone (GnRH) agonist (n=184) or a GnRH antagonist protocol (n=146) was used for pituitary suppression. Ovarian sensitivity was defined as the serum estradiol level on triggering day per 500 IU of administered gonadotropins (OS[a]) or the retrieved oocyte number per 500 IU of administered gonadotropins (OS[b]). Results: Univariate analysis revealed that the serum P level on triggering day was associated with the serum estradiol level on triggering day (r=0.379, p<0.001), the number of follicles ${\geq}14mm$ (r=0.247, p<0.001), the number of retrieved oocytes (r=0.384, p<0.001), and ovarian sensitivity (OS[a]: r=0.245, p<0.001; OS[b]: r=0.170, p=0.002). The woman's age, body mass index, antral follicle count, and basal serum follicle stimulating hormone and estradiol levels were not associated with serum P level on triggering day. The serum P level on triggering day did not show significant variation depending on the type or cause of infertility, pituitary suppression protocol, or the type of gonadotropins used. Conclusion: The serum P level on triggering day was closely related to the response to ovarian stimulation.