• Development and Reproduction
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• v.15 no.3
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• pp.257-263
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• 2011

Gonadal development and reproductive cycle of Aplysia kurodai inhabiting the coastal waters of Jeju Island, Korea were investigated based on monthly changes of gonadosomatic index, gametogenesis, and developmental phases of ovotestis. A. kurodai was simultaneous hermaphrodite; the ovotestis generally embedded in the posterior dorsal surface of the brownish digestive gland. The ovotestis is composed of a large number of follicles, and both oocytes and sperm are produced in the same follicles. In the sampling periods, the adult A. kurodai population have characteristic of seasonal pattern present during only 10 months. The reproductive cycle can be grouped into the following successive stages in the ovary: inactive (December to February), active (December to April), mature and spawning (April to September). The gonadal development of A. kurodai coincided with rising temperature, and spawning occurred from April to September, when the temperature was high. The histological observations of the ovotestis suggested that this species have a single spawning season that extend over six months.

• The Korean Journal of Malacology
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• v.32 no.2
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• pp.67-71
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• 2016

In order to obtain a large number of fertilized eggs for seedling production, experiment was carried out examine effects of serotonin on spawning of the Pacific oyster Crassostrea gigas. The shorter response time to initial spawning in case of serotonin injection showed, the higher serotonin injected with 7.6-27 min. The response time to initial sperm releasing showed the same tendency with female. The highest response rates and eggs amount spawned were showed in the highest concentration. The serotonin injection had no effect on frequency of germinal vesicle breakdown (GVBD), fertilization and hatching rate.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.11
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• pp.1514-1517
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• 2000

In chicken, exogenous genes introduced into germinal crescent region (GCR) of the early developmental stage, where primordial germ cells (PGCs) were concentrated, were successfully transferred to the gonads via PGCs. The foreign genes were also confirmed to be successfully incorporated into F1 and F2 generations. We tried to incorporate the exogenous genes into PGCs by lipofection, then the DNA mixture was injected into GCR at stage 3-5 or 9-11 of embryonic development (Hamburger and Hamilton, 1951). The manipulated eggs were incubated, and hatched chicks were reared until sexual maturation. F1 generation was obtained from the DNA-treated chicken (DNA-chicken) mated with normal birds. Furthermore, F2 generation was also obtained from the F1 chicken mated with normal birds. The transfer of introduced foreign genes were confirmed by marker gene detection methods and PCR analysis in the hatched chicks, F1 and F2 generations. However, in our experiments, DNA-chickens showed abnormal characteristics such as low egg production rate, abnormal appearance and decreased number of spermatozoa. In the case of F1 chicken, low egg production and the deterioration of sperm capacity for insemination in male chicken were observed.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.6
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• pp.609-613
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• 1997

The reproductive performance of forty two male broilers divided into three similar groups and fed on isocaloric and isonitrogneous diets containing 0, 10 or 20% water washed neem seed kernel meal (WWNSKM) was investigated from 20 to 32-wks of age. Results on semen characteristics revealed that feeding of WWNSKM led to significant (p < 0.05) reduction in semen volume, sperm concentration associated with increased incidences of morphological abnormalities in the spermatozoa when compared to that of the control birds. A drastic reduction in the fertilizing ability of spermatozoa was observed, the adverse effects being more at higher inclusion level of the cake. Hatchability of eggs also declined in the WWNSKM fed group. Histological examination of testes revealed a higher number of degenerating cells and poor spermatogenesis along with multinucleated giant cells in the seminiferous tubules of the testes of birds receiving the high dose of WWNSKM in diet. It may be concluded that the feeding of WWNSKM by incorporating in isocaloric and isonitrogneous diets to cockerels is associated with adverse effect on their fertility.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.5
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• pp.480-485
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• 2003

Morphology of the spermatozoa from the testes of the catfish (Pseudobagrus brevicorpus) was studied by transmission and scanning electron microscopy. The spermatozoa of P. brevicorpus are approximately $82.25\pm0.06\;{\mu}m$ in length and relatively simple cells composed of a spherical head, a short midpiece and a tail as in most teleost fish, The nucleus measuring about $2.00\pm0.02\;{\mu}m$ in length is depressed with a deep nuclear fossa of about $1.05\pm0.03\;{\mu}m$ in length three fifths of the nuclear length. The nuclear fossa contains the proximal and distal centrioles. The two centrioles are oriented approximately $150^{\circ}$ to each other. The mitochondria are arranged in two layers and their number is 12 or more. They are separated from the axoneme by the cytoplasmic canal. The axoneme is the 9+2 microtubular pattern and has inner but no outer dynein arms as in other bagrids. The axonemal fins were the closed to axonemal doublet 3 and 8. The axonemal fins and lost outer dynein arm are shared in Bagridae and the deep nuclear fossa is shared in Siluriformes. The axonemal fins observed in Bagridae and Amblycipitidae of Siluriformes might be the apomorphic character in Ostariophysi.

• Korean Journal of Animal Reproduction
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• v.16 no.3
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• pp.217-224
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• 1992

These studies were carried out ot investigate on the transferred embryo development following ultrarapid frozen for 8-cell and morula of in vitro fertilization mouse embryos. The post-thaw embryo survival was evaluated and compared by cell stage of embryos and by equilibration time before ultrarapid freezing. The results obatined were summerized as follows: 1. The effects of equilibration time of 3 vs. 6 minutes before ultrarapid freezing and after thawing on the morphological survival and the viability of 8-cell and morulas embryos were not significant. 2. When the ultrarapid frozen-thawed 32 eight-cell and 33 morula embryos, and 30 fresh blastocysts were transferred to pseudopregnant recipient mice, the number of normal offsprings produced were 9(28.1%), 14(42.4%) and 18(60.0%), respectively. From the above resutls, it was concluded that the optimal conditions of pH osmolality of the media for mouse IVF and embryo culture, and the period of sperm preincubation might be 7.1, 310 mOsm and 120 min., respectively,a nd somewhat high conception rate might be resulted from transfer of frozen embryos of morula stage and fresh embryos of blastocyst stage.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.2
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• pp.164-173
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• 2012

Objectives: Epichlorohydrin is a material that has been predicted to have high volatility and strong toxicity and is used normally in working area. Therefore, the hazardous and dangerous level and the foreign management system about epichlorohydrin should be invested at home and abroad and through hazard assessment for occupational environment measurement and exposure status of industrial workers in domestic working area. Methods: To assess risk and to suggest Development and Adoption to prevent health damage of workers owing to the epichlorohydrin exposure, the hazardousness and dangerousness of epichlorohydrin and its practical examples and regulation level for domestic and abroad health impairment are researched on the base of various references. Results: The epichlorohydrin caused skin and mucus membrane irritation, respiratory paralysis, kidney and live damage under the influence of acute toxicity and in animal study, it was confirmed as a doubtful carcinogenic substance to trigger reducement of sperm number and reproduction ability, abnormal spermatogenesis, mutagen, increase of forestomach epithelium and occurrence of papilloma and so on, as well as it induced stimulus asthma and allergic contact dermatitis for exposure workers. Conclusions: Epichlorohydrin was found to occur allergic contact dermatitis, carcinogenesis doubt and reproduction toxicity and was verified as a material which would be established reinforcement of management level to care health of handlers, such as denotement dangerousness of skin absorption.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.4
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• pp.283-294
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• 2021

A genetic etiology of male infertility is identified in fewer than 25% of infertile men, while 30% of infertile men lack a clear etiology, resulting in a diagnosis of idiopathic male infertility. Advances in reproductive genetics have provided insights into the mechanisms of male infertility, and a characterization of the genetic basis of male infertility may have broad implications for understanding the causes of infertility and determining the prognosis, optimal treatment, and management of couples. In a substantial proportion of patients with azoospermia, known genetic factors contribute to male infertility. Additionally, the number of identified genetic anomalies in other etiologies of male infertility is growing through advances in whole-genome amplification and next-generation sequencing. In this review, we present an up-to-date overview of the indications for appropriate genetic tests, summarize the characteristics of chromosomal and genetic diseases, and discuss the treatment of couples with genetic infertility by microdissection-testicular sperm extraction, personalized hormone therapy, and in vitro fertilization with pre-implantation genetic testing.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.1
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• pp.31-37
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• 2021

The mass production of fertilized eggs of the convict grouper Hyporthodus septemfasciatus was studied from 2013 to 2020 for industrial aquaculture. The experiment was divided into two groups. Group 1 broodstock was raised from wild-caught fry and used from 2013 to 2020. Group 2 broodstock was raised from artificially propagated fry and used from 2019 to 2020. Males used to collect sperm for artificial insemination weighed more than 7 kg. The effects of various hormones on artificial ovulation were investigated from 2013 onward. Among these, luteinizing hormone-releasing hormone analogue (LHRHa) at 100 ㎍/kg body weight showed the most effective results and was used for artificial egg collection from 2014 onward. In Group 1, the average total egg production per year, average egg production per individual, fertilization rate, and hatching rate were 26,143 mL, 609.7 mL, 93.3%, and 91.8%, respectively, and in Group 2, were 2,750 mL, 316.5 mL, 92.1%, and 90.4%, respectively. Based on these results, we showed that a large number of fertilized eggs for artificial seeding could be produced consistently. Moreover, the mass production of fertilized eggs in Group 2 establishes a foundation for the complete aquaculture cycle of H. septemfasciatus.

• Clinical and Experimental Reproductive Medicine
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• v.49 no.1
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• pp.70-73
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• 2022

Objective: This study was conducted to assess the efficacy of subcutaneous granulocyte colony-stimulating factor (G-CSF) for treating thin endometrium. Methods: Data from 88 infertile women with thin endometrium (<7 mm) aged 23 to 40 years were evaluated retrospectively over a period of 1 year. In group 1, subcutaneous infusion of G-CSF (300 ㎍/mL) was administered to 44 women along with other supplemental treatments. If the lining did not exceed 7 mm within 72 hours, a second infusion was administered. In group 2, which also had 44 women, only estradiol valerate and sildenafil were administered, while subcutaneous G-CSF infusion was not. Embryo transfers were performed once the lining exceeded 7.5 mm. The efficacy of G-CSF was evaluated by assessing the thickness of the endometrium before embryo transfer, pregnancy rates, and clinical pregnancy rates. Results: There were no differences between the groups regarding demographic variables, egg reserves, sperm parameters, the number of embryos transferred, and embryo quality. The pregnancy rate was significantly higher in group 1 (60%, 24 of 40 cases) than in group 2 (31%, 9 of 29 cases) (p<0.001). The clinical pregnancy rate was also significantly higher in group 1 (55%) than in group 2 (24%) (p<0.001). Conclusion: Subcutaneous G-CSF infusion improved the thickness of the endometrium when it was thin. To the best of our knowledge, this is the first documented study to clearly demonstrate the benefits of subcutaneous G-CSF infusion for treating thin endometrium.