• Journal of fish pathology
• /
• v.2 no.2
• /
• pp.53-70
• /
• 1989

An ovarian parasite, Marteilioides chungmuensis of the Pacific oyster, Crassostrea gigas has been observed on several occasions in the Pacific sector of production of this oyster species(Matsuzato et al., 1977 ; Chun, 1979). This study was carried out on the specimens collected at Hwado, Och'$\check{o}$n, and Sinchang respectively located the southern, western, and eastern coasts of Korean Peninsula from 1986 through 1988 to investigate M. chungmuensis to the Pacific oyster. Uitrastructural studies were also carried out on infected oysters, to allow detailed examination of the structure and consepuently the systematic position of this parasite. Infection rates of M. chungmuensis at Hwado and Och'$\check{o}$n oyster farms were 5.3% and 4.2% each in 1986, 6.7% and 2.8% each in 1987, but they were not found at Sinchang oyster habitat. M,. chungmuensis-infected oysters were found from June to November at Hwado and from June to October at Och'$\check{o}$n. Twenty five of three hundred oysters transplanted from Sinchang to Hwado were found infected with M. chungmuensis. Some abnormal eggs infected with M. chungmuensis are liberated through the gill together with normal mature eggs on the spawning and the rest remain necrotized after spawning season. The earliest known stages consist of a stem cell or primary cell, including a secondary cell in which ovoid haplosporosomes are found. During sporulation, 2 or 3 secondary are produced by exogenous budding from the first secondary cell and, each secondary cell evolves into a sporont upon the tertiary cell differentiation (enodogenous budding) ; then, haplosporosomes are formed in the young sporont. Internal cleavages involve the differentiation of one tricellular spore per sporont. The outermost spore cell contains membrane-bounded osmiophilic bodies : the middle and the inner, most spore cells contain high density cytoplasmic ribosomes. The mechanism of spore formation from the stem cell of M. chungmuensis is the simplest of the class Paramyxea known up to now.

• Journal of Food Hygiene and Safety
• /
• v.13 no.2
• /
• pp.106-111
• /
• 1998

This study has been focused on both estrogenic and proliferating activity of genistein (GEN) and bisphenol A (BPA). GEN and BPA enhance the proliferation of estrogen-dependent MCF-7 human breast cancer cells at concentrations as low as 100 nM of GEN and 8 ng/ml of BP A achieving similar effect to that of estradiol at 1 nM. Expression of the estrogen responsive gene, pS2 was also induced in MCF-7 cells by treatment with genistein at dose as low as 1 nM and BPA at dose as low as 4 ng/ml. Using 21 day-old ovariectomized nude mice, we examined end-bud formation and mammary gland development after treatment with bisphenol A or genistein. Compared with untreated control, mammary gland development and end-bud formation were significantly increased in mice fed genistein or bisphenol A (p<0.05). Taken together, it is concluded that GEN and BP A can act as an estrogen agonist resulting in cell proliferation and induction of the estrogen responsive pS2 gene in MCF-7 cells in vitro and in athymic mice in vivo, respectively. Therefore, it is suggested that GEN and BP A might modulate human endocrine system and these compounds might be considered as a endocrine modulator at the low levels of doses.

• Radiation Oncology Journal
• /
• v.16 no.3
• /
• pp.225-231
• /
• 1998

Purpose : To determine whether TNF-$\alpha$ increases the antitumor effect of radiotherapy in murine syngeneic tumor system. Materials and Methods : Syngeneic murine tumors of MCa-K or MCa-4 (mammary carcinoma), OCa-I (ovarian carcinoma), or HCa-I(hepatocarcinoma were grown in hind legs of C3Hf/HeJ mice. When tumors were grown to 6 mm in mean diameter mice were treated with TNF-$\alpha$, radiation, or combination of the both. Gamma-radiation was given as a single dose of 30 Gy for HCa-I and 15 Gy for other tumors using Cobalt-60 teletherapy unit. A novel TNF-$\alpha$ mutein developed in Korea, was intraperitoneally administered daily at a dose of 10 ug per mouse for 7 days. In combination of radiation and TNF-$\alpha$, the drug was started 1 hour after radiation. Tumor growth delay assay was used to measure the tumor response to the treatment. Results : Among 4 tested tumors, TNF-$\alpha$ alone showed significant antitumor activity in MCa-K and OCa-I tumors, which showed absolute growth delay (AGD) of 5.0 days and 6.5 days, respectively. In combination with radiation, TNF-$\alpha$ showed significant delay of AGD (41.1 days) in OCA-I compared to AGDs of TNF-$\alpha$ alone and radiation, i.e., 6.5 days and 26.9 days, respectively(p<0.05). Enhancement factor was 1.29 in OCa-I, which showed supraadditive effect. TNF-$\alpha$ did not show significant delay of AGDs in the remaining 3 tumors compared to AGDs of TNF-$\alpha$ alone and radiation. Conclusions: TNF-$\alpha$ alone showed antitumor effects in MCa-K and OCa-I. In combination with radiation, TNF-$\alpha$ acted in supraadditive way in OCa-I only. The results of this study imply that the combination of TNF-$\alpha$ and radiation has different therapeutic potential depending on tumor model and further study is advocated.

• Korean Journal of Ichthyology
• /
• v.18 no.3
• /
• pp.184-192
• /
• 2006

To investigate reproductive cycle of Tridentiger obscurus in Jeju, total 408 fish were collected in brackish area (May 2004 to August 2005) and total 271 fish were collected in tidal pool (July 2004 to August 2005), respectively. Water temperature ranged $11.0{\sim}21.6^{\circ}C$ in brackish area. Water temperature of tidal pool ($11.1{\sim}24.5^{\circ}C$) in 2005 was similar to that of brackish area although it were highest $30.1{\sim}29.2^{\circ}C$ from July to August in 2004. In brackish area, female gonadosomatic index (GSI) increased in April and maintained high values from May to August. The reproductive cycle can be grouped into the following successive stages in the ovary: immature (November to May), maturing (March to September), ripe and spawning (May to September), and degenerating (July to December). In the tidal pool, female GSI rapidly increased in April and maintained high values until July in 2005. However, it has been low in July 2004 when water temperature was highest. The reproductive cycle can be grouped into the following successive stages in the ovary: immature (August to April), maturing (March to August), ripe and spawning (March to July), and degenerating (July to August 2004 and August 2005). Fecundity of mature female ranged from 1,214 to 12,109 in brackish and ranged from 2,427 to 13,892 in tidal pool area. The fecundity of fish in the tidal pool was significantly higher than that of fish in brackish area. Fecundity was correlated positively with total length and body weigh. Although the large group (> 111 mm total length) in brackish area observed only in spawning season, one in the tidal pool observed from October 2004 until next spawning season. Frequency of the large group was 0 to 12% and 11.4 to 57.9% in brackish area and tidal pool, respectively. These results were indicated that gonadal development of T. obscurus was affected to water temperature and day length.

• Journal of Marine Life Science
• /
• v.5 no.2
• /
• pp.35-42
• /
• 2020

17β-estradiol (E₂) is a natural hormone secreted by ovary, and continuously discharged from household and livestock wastewater into aquatic environment. Due to its strong estrogenic activity, it has adverse effects on development and reproduction in crustacean as an endocrine disrupting chemical. Although ecdysteroid signaling pathway play a key role in development in crustacean, little information on transcriptional modulation of ecdysteroid-related genes in response to E₂ is available in small crustacean. Here, we investigated the acute toxicity of E₂ to obtain 24-h LC_x values in the brackish water flea Diaphanosoma celebensis. Time-dependent expression patterns of seven ecdysteroid pathway - related genes (CYP314a1, EcRA, EcRB, USP, ERR, Vtg, VtgR) were further examined using quantitative real time reverse transcriptase polymerase chain reaction (qRT-PCR). As results, 24-h LC₅₀ and LC₁₀ values were 9.581 mg/l and 4.842 mg/l, respectively. The mRNA expression of CYP314a1, EcRA, USP, VtgR was significantly up-regulated at 12 or 24 h after exposure to E₂. These findings indicate that E₂ can affect their molting and reproduction by modulating the expression of ecdysteroid pathway - related in D. celebensis. This study will be useful for better understanding of molecular mode of action of endocrine disrupting chemicals on molting process in small crustacean.

• Journal of Radiation Protection and Research
• /
• v.21 no.4
• /
• pp.273-284
• /
• 1996

Embryos and fetuses are more sensitive to various environmental agents than are adults or children. The biological effects such as intrauterine death and malformation are closely connected with prenatal exposure very various agents. The sensitivity of these embryonic/fetal effects depends on the stage of pregnancy. From the viewpoint of fetal development, embryonic and fetal stages can be divided into three stages : Preimplantation, organogenetic and fetal. Each stage corresponds to 0 to 4.5days, 4.5 to 13.5days, and 13.5days of gestation in mice, respectively. Many studies on the biologcal effects of mice irradiated by ${\gamma}-rays$ at various stages during organogenesis and fetal period have been performed. Based on these results, the dose-effect and dose-response relationships in malformations, intrauterine death, or retardation of the physical growth have been practically modeled by the ICRP(International Commission on Radiological Protection) and other international bodies for radiation protection. Many experimental studies on mice have made it clear that mice embryos in the preimplantation period have a higher sensitivity to radiation for lethal effects than the embryos/fetuses on other prenatal periods. However, no eratogenic effects of radiation at preimplantation stages of mice have been described in many textbooks. It has been believed that 'all or none action results' for radiation of mice during the preimplantation period were applied. The teratogenic and lethal effects during the preimplantation stage are one of the most important problems from the viewpoint of radiological protection, since the preimplantation stage is the period when the pregnancy itself is not noticed by a pregnant woman. There are many physical or chemical agents which affect embryos/fetuses in the environment. It is assumed that each agents indirectly effects a human. Then, a safety criterion on each agent is determined independently. The pregnant ICR mice on 2, 48, 72 or 96 hours post-conception (hpc), at which are preimplantation stage of embryos, were irradiated whole body Cesium-gamma radiation at doses of 0.1, 0.25, 0.5, 1.5, and 2.5 Gy with dose rate of 0.2 Gy/min. In the embryos from the fetuses from the mice irradiated at various period in preimplantation, embryonic/fetal mortalities, incidence of external gross malformation, fetal body weight and sex ratio were observed at day 18 of gestation. The sensitivity of embryonic mortalities in the mice irradiated at the stage of preimplantation were higher than those in the mice irradiated at the stage of organogenesis. And the more sensitive periods of preimplantation stage for embryonic death were 2 and 48 hpc, at which embryos were one cell and 4 to 7 cell stage, respectively. Many types of the external gross malformations such as exencephaly, cleft palate and anophthalmia were observed in the fetuses from the mice irradiated at 2, 72 and 96 hpc. However, no malformations were observed in the mice irradiated at 48 hpc, at which stage the embryos were about 6 cell stage precompacted embryos. So far, it is believed that the embryos on preimplantation stage are not susceptible to teratogens such as radiation and chemical agents. In this study, the sensitivity for external malformations in the fetuses from the mice irradiated at preimplantation were higher than those in the fetuses on stage of organogenesis.

• Parasites, Hosts and Diseases
• /
• v.27 no.4
• /
• pp.231-248
• /
• 1989

The growth and development of the metacercariae of F. seoulensis cultivated in vitro or on the chick chorioallantois were assessed by comparison with the optimum process of maturation in albino rats and new born chickens. The process of maturation was divided for convenience into six stages: Stage 1 ; cell multiplication, Stage 2; body shaping, Stage 3; separation of genital anlagen, Stage :1 organogeny, Stage 5; gametogony, and Stage 6: oviposition. In Hank's and Tyrode's .solutions, the metacercariae were alive up to 200 days or more at $4^{\circ}C$ without any development. The in vivo maturation process in rats or chicks was as follows: stage 1 from 6 hours; stage 2 from 24 hours; stage 3 from 48 to 72 hours; stage 4 from 3 to 4 days; stage 5 from 4 to 5 days; and stage 6 from 5 to 8 days. Despite unsuccessful infection of the metacercariae to 12 day old chicks, fully mature worms of stage 5 or 6 were recovered from new born chicks (1 to 2 days old), The metacercariae of F. seoulensis grown in vitro were up to stage 3 and no further maturation was observed. Of various media employed, the medium NCTC 109 (Gibco) or NCTC 135(Gibco) supplemented with 20% egg yolk or 20% whole egg macerate or 0.5% yeast was basically required for the earlier development of the fluke. It took 16.1 days(in average) to reach the stage 3 after cultivation. The metacercariae cultivated on the chorioallantoic membranes of 6∼13 day old chick embryo at 37∼38℃ showed their full development up to stage 5 or 6. However, the worms were in general remarkably retarded, compared with those grown in rats or chickens. In the experiments of worm transplant, although the transfer was failed from in vitro culture to in vivo of rats(Per os), the transplants from in vitro culture to the chorioallantois and from the choriollantois to in vivo of rat host were successful with or without development of the transferred worms. In the present study, it was observed that the metacercariae of F, seoulensis can be maintained in vitro media with poor development as well as fully matured in 1 to 2 day-old chicks or on the chorioallantois at a very low rate.

• Radiation Oncology Journal
• /
• v.26 no.1
• /
• pp.65-73
• /
• 2008

Purpose: Women with breast cancer diagnosed at an age of 40 years or younger have a greater prevalence of germline BRCA1 and BRCA2 mutations than the prevalence of women with breast cancer diagnosed at older ages. Several immunohistochemical characteristics have been identified in breast cancers from studies of Caucasian women with BRCA1/2 mutations having familial or early-onset breast cancers. The aim of this study is to determine whether early-onset breast cancer in BRCA1 or BRCA2 mutation carriers, who were not selected from a family history, could be distinguished by the use of immunohistochemical methods and could be distinguished from breast cancer in women of a similar age without a germline BRCA1 or BRCA2 mutation. We also analyzed the prognostic difference between BRCA1/2 related and BRCA1/2 non-related patients by the use of univariate and multivariate analysis. Materials and Methods: Breast cancer tissue specimens from Korean women with early-onset breast cancers were studied using a tumor tissue microarray. Immunohistochemical staining of estrogen receptor(ER), progesterone receptor(PR) and HER-2, as well as the histology and grade of these specimens, were compared. The prognostic impact of immunohistochemical and histological factors as well as the BRCA1/2 mutation status was investigated separately. Results: There were 14 cases and 16 deleterious BRCA1/2 mutations among 101 patients tested. A family history(4/14) and bilateral breast cancers(3/9) were high risk factors for BRCA1/2 mutations. BRCA1/2-associated cancers demonstrated more expression of ER-negative(19.4% versus 5.1%, p=0.038) and HER-2 negative than BRCA1/2 negative tumors, especially for tumors with BRCA1 tumors The BRCA1/2 mutation rate for patients with triple negative tumors(negative expression of ER, PR and HER-2) was 24.2%. Tumor size, nodal status, and HER-2 expression status were significantly associated with disease free survival, as determined by univariate and multivariate analysis, but the BRCA1/2 status was not a prognostic factor. Conclusion: Breast cancer that occurs in women with a germline BRCA1 or BRCA2 mutations have recognizable immunohistochemical features, which may be useful in identifying individuals that are more likely to carry germline mutations. Although the BRCA1/2 mutation status was not a prognostic factor in Korean women with early-onset breast cancer, more cases with a longer follow-up period are needed for further study.