• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.241-250
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• 1982

The structure of gonads, gametogenesis and reproductive cycle of the cockle, Fulvia mutice, were studied mainly by histological observation. The materials were monthly sampled in the southern area of Yeosu from October 1980 to September 1981. F. mutica was monoecious. The gonads were situated between the liver tissues and the outer fibronuscular layers compacted by the connective tissue fibers and muscle fibers beneath the outermost layer of simple cuboidal epithelium. The gonad was composed of a number of the ovarian sacs and the testicular tubules which form the tubular structure. Testicular tubules in the mature stage sometimes contained 'testis-ova' The undifferentiated mesenchymal tissues and the eosinophilic cells were abundantly distributed on the germinal epithelium in the early development stage. With the further development of the ovary and testis, these tissues and cells gradually disapprared. The undifferentiated mesenchymal tissues and the eosinophilic cells are related to the growing of the oocytes and spermatocytes . Early multiplicating oogonium was about $10{\mu}m$ in diameter. As the oocytes grow to $27-34\times50-58{\mu}m$ by increasing cytoplasm, the oocytes connected to the basement membrane by their egg-stalks. The ripe eggs were about $60{\mu}m$ in diameter and they were surrounded by gelatinous membrane. Most male germ cells in mature stage were transformed into the spermatozoa and they formed the sperm bundles. After spawning, undischarged ripe eggs and spermatozoa remained in the ovarian sac and the testicular tubule respectively for some time, then they finally degenerated. Especially the early spent ovarian sacs in May did not contract significantly and then they took part in the secondary maturation within two or three months during the summer season. The monthly changes of the fatness well agreed with the reproductive cycle. The reproductive cycle of F. mutica could be classified into six successive stages : multiplicative, growing, mature, spent, degenerative and recovery stage. It seems that the spawning season is closely rotated to the water temperature, and the spawning occurs from May to October at about $20^{\circ}C$ in water temperature. The peak spawning seasons appeared twice a year between June and July and in September. Acknowledgement The authors wish to express their gratitude to Dr. Kim, In Bae, Dr. Chun, Seh Kyu and Dr. Yoo, Sung Kyoo of National Fisheries University of Busan and Mr. Min, Byoung Seo of National fisheries Research and Development Agency for their critical reading of the manu script.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.6
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• pp.509-519
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• 1987

Annual reproductive cycle of the Damselfish, Chromis notatus collected monthly at the four coastal areas around Chejudo, Korea are studied on the bases of histological observations of gonadal tissue and various quantitative variables including gonadosomatic index (GSI), fatness, egg diameter composition and the first maturity. The ovary consisted of a pair of saccular structure with many ovarian sacs. Oogonia proliferated along the germinal epithelium of the ovarian sac. Young oocytes with basophilic cytoplasm showed several nucleoli along the nuclear membrane. When the oocytes reached about $450{\mu}m$ in diameter, nucleus migrate toward the animal pole, nuclear membrane disappeared and most of cytoplasm were filled with yolk materials and oil drops. After ovulation, residual follicle and growing oocytes remaining in the ovarian sacs degenerated. But early young oocytes without follicle layer were not degenerated, and growing continuously till the next year. The testis consisted of a pair of lobular structures in the right and left were united in the posterior seminal vesicle. Cortex of testis was composed of many sperm ducts connected with lobuli. GSI began to increase from March, starting season of longer day length and higher water temperature, and reached the maximum value between June and August. It began to decrease from September with the lowest value appearing between October and February without any evident variation. The annual reproductive cycle could be devided into five successive stage : growing(April to Many), mature(May to August), ripe and spent (June to August) and recovery and resting stage(September to March). The spawning peak occurred from June to August. According to the frequency distribution of egg diameter, Chromis notatus was a polycyclic species to spawn twice or more in a spawning season. Fatness, correlated with gonadal phases, was remarkably decreased by spawning. Percentage of the first maturity . in femate and male fish ranging from 7.0 to 7.9 cm were $50\%$ and from 9.0 to 9.9 cm in total length $100\%$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.2
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• pp.71-96
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• 1977

Early development Linuparus trigonus(von Siebold) has been studied based on the samples collected monthly in Je-ju Island, Korea from February, 1975 to January, 1977. Gametogenesis, reproductive cycle, embryonic development were investigated by histological mettled, and morphological description was made on the first phyllosoma larva which reared in the laboratory. Testis is composed of two tubular duct which are symmetrical with H-shaped appearance. Outer layer of testis is of fibrous connective tissue capsule. In the lumen there is a convoluted seminiferous tubule with interstitial tissue. Ovary is a pair of symmetrical blind tubular lobes, and the midportions are connected each other. The ovary consists of a couple of ovarian sacs partitioned by two-layered connective tissue fibers. Proliferation of spermatogonia are observed all the year around on the germinal epithelium of seminiferous tubule. Partial spermatogenesis is always in progress, and the spermatozoa appear all the year around in the tubules. Nutrition of early oogonia is supplied by fibrous mesenchyme which is abundantly distributed in ovarian sacs. Oocytes grow and couplete maturation divisions in the follicle layers. They finally develop into mature ova before spawning. Reproductive cycle is classified into four successive stages; multiplication stage from September to December, growing stage from January to March, maturation division stage from April to May and mature stage from June to August. Spawning takes place from May to August with peak spawning from Into July to early August. Cleavage type is superficial. Blastopore is formed in blasto-disc region which is proliferation of blastoderm cells. Germinal layers are also derived from tile region. Mesoderm formation is originated from endodermal cells which are formed front the blasto-disc region. The endodermal cells are separated by the process of delamination from yolk sac and take part in the formation of the mid-gut. Morphological characteristics of first phyllosoma larva are different from the larvae of other Palinurid and Scyllarid species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.423-435
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• 1984

The reproductive cycle of the small filefish, Rudarius ercodes was investigated based on the annual variations of gonadosomatic index(GSI) and hepatosomatic index(HSI) by electronic and photic microscophy. The specimens used were collected at the coastal area of Benden island, Sizuokagen, Japan, from September 1982 to August 1983. GSI began to increase from March, starting season of longer daylength and higher water temperature, and reached the maximum value between June and August. It began to decrease from September with the lowest value appearing between November and February without any evident variation. The annual variations of HSI were not distinct in male filefish and were negatively related to GSI in female : HSI decreased in the summer season when the ovary was getting mature and reached the maximum in the winter season when the ovary was getting retrogressive. The ovary consisted of a pair of saccular structure with numerous ovarian sacs branched toward the median cavity. Oogonia divided and proliferated along the germinal epithelium of the ovarian sac. Young oocytes with basophile cytoplasm showed several scattering nucleoli along the nuclear membrane. when the oocytes growing to about 300 ${\mu}m$, nuclear membrane to disappear with nucleus migrating toward the animal pole. The regions of protoplasm were extremely confined within the animal hemisphere in which most of cytoplasms were filled with yolk materials and oil drops. After ovulation, residual follicles and growing oocytes remaining in the ovarian sacs degenerated. But perinucleatic young oocytes without follicles formed were not degenerated, and growing continuously still in the next year. Mitochondria and endoplasmic reticula in the cytoplasm remarkably increased with oocytes maturing and yolk accumulating. Those were considered to be functionally related to the yolk accumulation. Five or six layers of possible vitellogenin, oval-shaped disc structures with high electron density, appeared in the apex of follicular processes stretching to the microvilli pits of mature oocytes. Testis consisting of a pair of lobular structures in the right and left were united in the posterior seminal vesicle, Cortex of testis was composed of several seminiferous tubules, and medulla consisting of many sperm ducts connected with tubules. Steroid hormone-secreting cells with numerous endoplasmic reticula and large mitochondria of well developed cristae were recognized in the interstitial cells of the growing testis. Axial filament of spermatozoon invaginated deeply in the central cavity of the nucleus and the head formed U-shape with acrosome severely lacking, mitochondria formed large globular paranuclei at the posterior head, and microtubular axoneme of the tail represented 9+9+2 type. The annual reproductive cycles could be divided into five successive stages : growth(March to July), maturation(May to September), Spawning(mid May to early October) and resting stages(October to February). The spawning peak occurred from June to August.

• Korean Journal of Ichthyology
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• v.27 no.2
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• pp.86-94
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• 2015

Egg development and early life history of the endangered species, Microphysogobio rapidus was investigated to get a basic information for biological characteristics and recovery strategy. Eggs were obtained from females by injecting Ovaprim (0.5 mL/kg) and artificially fertilized by dry method in the laboratory. The mature eggs were slightly adhesive and separated with light bluish green and $0.63{\pm}0.02mm$ (n=20) in diameter. Number of eggs in the ovaries were $3,827{\pm}1,225$ (2,850 ~ 5,916). The hatching occurred at 72 hours after fertilization under water temperature of $21{\pm}1^{\circ}C$. The newly-hatched larvae were $2.79{\pm}0.04mm$ (n=10) in total length. At 5 days after hatching, they were average $4.10{\pm}0.07mm$ (n=10) in TL and their yolk sacs were completely absorbed. 30 days after hatching, they became to juvenile stage and reached $9.74{\pm}0.24mm$ (n=10) in TL. At 100 days after hatching, the band patterns and external form were similar to those of adults, average $27.00{\pm}1.94mm$ (n=10) in TL.

• Clinical and Experimental Reproductive Medicine
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• v.30 no.1
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• pp.85-93
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• 2003

Objective : To evaluate the safety and efficacy of selective fetal reduction (SFR) and compare the outcome of twin pregnancy after SFR in multiple pregnancy induced by assisted reproductive technology (ART) with that of natural twin pregnancy. Methods : From September 1995 to March 2002 in Ajou University Hospital, SFR was performed in 79 patients whose gestational sacs were more than 3. Of these 79 patients, 47 patents resulted in twin pregnancy after SFR. SFR was performed using transvaginal intracardiac KCl injection at gestational age of $6{\sim}9$ weeks. Control group was composed of 264 patients with natural twin pregnancy, who delivered after intrauterine pregnancy at 24 weeks, from June 1994 through December 2002. We compared Obstetric and perinatal outcomes between SFR group and natural twin group. Results: Among 47 patients with twin pregnancy after SFR, 2 spontaneous abortion were occurred at intrauterine pregnancy at 8 and 19 weeks. Obstetrical and perinatal outcomes were available in 43 patients. Single intrauterine fetal death was occurred in 1 of 43 (2.3%) patients in SFR group. Incidence of preterm labor, premature rupture of membrane, preeclampsia and placenta previa were similar, but gestational diabetes mellitus (GDM) was occurred more frequently in SFR group (3 (7.0%) vs 4 (1.5%), p=0.02). Mean gestational age, mean birth weight, incidence of discordancy, use of intubation and ventilation, incidence of fetal anomaly, low (<7) Apgar score and intrauterine growth restriction were similar in both groups. Conclusion: Twin pregnancy after SFR has the increased incidence for GDM but other obstetric and perinatal outcome was similar compared with natural twin pregnancy. So SFR is a safe and effective procedure, so we suggest SFR is needed in multifetal pregnancy more than triplet.

• Korean Journal of Environmental Biology
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• v.20 no.3
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• pp.245-255
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• 2002

In order to obtain the basic information for seedling production of venus clam, Protothaca jedoensis, the annual reproductive cycle was investigated mainly by histological observation from September 1998 to August 1999. P. jedoensis was dioecious. The gonads are located between the digestive diverticula and muscle tissue of the foot. The ovary was composed of a number of ovarian sacs, and the testis was composed of several testicular tubules. The condition index was reached its maximum (20.0) in February, and then decreased to 11.5 in June. In August, the value was the lowest (9.0) and then increased slowly. Minimum size for the sexual maturation of individuals were 38.4 mm in shell length. One the other hand, the size of mature oocytes was ranged to $50-60\mu{m}$ in diameter and testis-ova was observed in testis of the mature stage. The reproductive cycle of P. jedoensis could be classified into five successive stages: early active (December to February), late active (January to April), ripe (March to July), partially spawned (June to August) and spent/inactive (July to January) stages.

• Journal of Veterinary Clinics
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• v.27 no.6
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• pp.746-750
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• 2010

Three military working dogs (MWDs) were diagnosed with perianal fistulae after a complete physical examination and rectal palpation. The initial treatment protocol was used with short-term oral ciclosporine (CyA) and ketoconazole and 0.1% topical tacrolimus ointment. When lesions were nearly healed, treatment was continued with 0.1% tacrolimus ointment only at a lower frequency. The lesions improved significantly within 2-8 weeks with no noticeable side effects. Complete recovery was determined at weeks 13, 6, and 4 for cases 1, 2, and 3, respectively. This combination protocol was effective at resolving or reducing perianal fistulae (PAF) lesions even communicating with anal sacs in three dogs. The major benefit of this protocol was the rapid reduction of fistulae lesions and this could be helpful to extend the pain-free period. Moreover, this protocol appeared cost-saving as well as time-saving option for PAF dogs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.135-144
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• 1980

The reproductive cycle and the breeding season of the freshwater clam, Anodonta (Sinanodonta) woodiana (Lea) have been investigated by histological examination of the gonadal development under photomicroscopy. The materials were monthly collected from the Nakdong River for one year from September 1979 to August 1980. Sexuality of Anodonta (Sinanodonta) woodiana is dioecious, and the species are ovoviviparous. The gonads are irregularly arranged from the subregion of mid-intestinal gland in visceral cavity to reticular connective tissue of foot. The ovary is composed of a number of small ovarian sacs, The epithelium of ovarian sac has a function of the germinal epithelium. Oogonia actively proliferate along the germinal epithelium of the ovarian sac, in which young oocytes are growing. The testis is composed of a number of seminiferous tubules, and the epithelium of the tubule has function of germinal epithelium, along which spermatogonia actively proliferate. A great number of undifferentiated mesenchymal tissue and eosinophilic granular cells are abundantly distributed between the growing oocytes and spermatocytes in the early development stages. With the further development of the ovary and testis these tissues and cells gradually disappear. Then the undifferentiated mesenchymal tissue and granular cells are considered to be related to the growing of the oocytes and spermatocytes. The gonads had function year-round the individuals which have various developmental stages of gonads appearing all the time. Spawning continued year-round except for the period of high temperature of water, during August and September. The peak spawning seasons appeared twice a year between January and March, and between June and July in 1980. Individuals which have trochophore larvae in the marsupium of the adult appeared year-round except September 1579 and August 1980. The rate of individuals which have glochidia in the marsupium was 72.7 percent in May 1980 which was the highest brooding fate.

• Korean Journal of Ichthyology
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• v.23 no.3
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• pp.198-205
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• 2011

Early life history of the endangered species, Gobiobotia macrocephala was investigated to provide baseline data for biological characteristics and recovery. Adult fish were sampled by spoon net at Hongcheon-gun, Gangwon-do, Korea in April to June 2010. The female's eggs were obtained by injecting Ovaprim and fertilized by dry method in the laboratory. The mature eggs were slightly adhesive and transparent with greyish and average 0.89${\pm}$0.04mm in diameter. The hatching of the embryo took place in about 107 hours after fertilization under water temperature of 23$^{\circ}C$ and newly hatched larvae were average 4.6${\pm}$0.16mm in total length. At 4 days after hatching, they were average 6.1${\pm}$0.20mm in total length and their yolk sacs were completely absorbed. From 15 days after hatching, they entered the juvenile stage and reached at 8.6${\pm}$0.67mm in total length. At the 100 days after hatching, their band patterns and external form were similar to those of adults, and they averaged 31.5${\pm}$3.32mm in total length.