• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2004.10a
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• pp.42-42
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• 2004

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.05a
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• pp.104-104
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• 2004

• Environmental Mutagens and Carcinogens
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• v.26 no.2
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• pp.53-58
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• 2006

Normally, environmental toxicants are classified as endocrine disruptors if they interfere with regulation of cellular function by endogeneous steroids through inhibition of receptor binding and/or transcriptional activation. So, many studies have been performed about agonist/antagonist of hormone receptor to study mechanisms of endocrine disruptors. If toxicants affect steroid biosynthesis and/or degradation and alter hormone homeostasis, these also are classified as endocrine disruptors. But there are not many studies of the mechanisms of endocrine disruptors on the basis of alteration of steroid biosynthesis and/or degradation. Isolation and culture of Leydig cells from testis is one of methods for the steroidogenesis screening assays to evaluate a substance for altering steroidogenesis. Leydig cells were harvested using the method described by Klinefelter with modifications. Leydig cells were purified by perfusion of testis and incubation ($34^{\circ}C$, 80cycles/minute, 20 minutes) with collagenase (0.25 mg/kg), centrifugal elutriation, percoll gradient centrifugation and BSA multidensity gradient centrifugation. To confirm if this method is one of appropriate tools to evaluate a substance for altering steroidogenesis, ketoconazole, positive control was administered to purified Leydig cells. Ketoconazole ($10^{-8}M$ and above) significantly reduced testosterone production in purified Leydig cells. From above results, we suggest that this method for steroidogenesis screening assay appears to be a appropriate tool to detect suspected compounds for altering steroidogenesis.

• Hwankyungkyoyuk
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• v.19 no.3
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• pp.93-101
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• 2006

The purpose of this study was to investigate the cognition of high school students and science teachers on the endocrine disruptors. Subjects of this study were 204 high school students and 26 science teachers. The results were as follows. Students obtained informations about endocrine disruptors mainly through mass media like TV, radio or lesson in school. Most of them were interested in endocrine disruptors and they thought that endocrine disruptors were very dangerous for people. And they preferred learning materials such as movies, images, and animations, but they didn't want to participate in activity of education on endocrine disruptors actively. Science teachers has agreed to needs of education on endocrine disruptors and has required education programs such as movies, images or animations for effective endocrine disruptors education.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.115.1-115.1
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• 2003

Cadmium, a human carcinogen, can induce apoptosis in various cell lines. Despite extensive research, the mechanisms of cadmium-induced apoptosis are poorly understood, and its toxicity and estrogenic potential in human are not clear. This study was performed to investigate the apoptotic activities of cadmium on two human breast cancer cell lines: MCF-7 cells, an estrogen receptor (ER) positive cell line, and MDA-MB-231 cells, an ER negative cell line. Both cells were treated with $CdCl_2$ 100$\mu$M for 12hrs, and the spoptosis was determined by DNA fragmentation, DAPI staining, and expression of caspase-9. (omitted)

• 대한생식의학회:학술대회논문집
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• 2005.06a
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• pp.114-114
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• 2005

• Biomedical Science Letters
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• v.8 no.2
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• pp.95-99
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• 2002

Endocrine disruptors are chemicals which can be found in our normal daily life. They can be easily ingested through plastic food containers, pesticides, etc. They include DDT, bisphenol A, benzophenone and phenylphenol, etc. Endocrine disruptor can be very harmful and toxic because it disrupts the normal function of the endogenous endocrine system. It has been reported that endocrine disruptor can cause the fatal strike in reproductive system central nervous system and the other part of the body. We have examined if the growth of lactic acid bacteria could be resistant to the endocrine disruptor. We have used Lactobacillus delbruekii as an experimental strain and benzophenone and phenylphenol for the comparison purpose. Experiments included the evaluation of turbidity, absorbance and actual cell counts. Although Lactobacillus delbruekii showed the higher resistance to benzophenone than phenylphenol it was still resistant to both benzophenone and phenylphenol. Because the experimental concentrations of benzophenone and phenylphenol were so high to compare with the actual concentration we meet in daily life, Lactobacillus delbruekii was considered to be sufficient to survive in the environmental concentration of these endocrine disruptors. This study should contribute to the development of fermented beverage with beneficial effect by lactic acid bacteria.

• Hwankyungkyoyuk
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• v.16 no.1
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• pp.12-24
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• 2003

Recently, endocnne dIsruptors have been known as one of the most harrnful chemical material. The purpose of this study is to investigate the cogintion and behavoor of milddle school students on the endocrine disruptors. To achieve this goal, survey research was conducted. Data were collected from 531 first and third-grade students in Suwon city. The main results of this study are summarized as follows FIrst, the mam source of information on the endocrine disruptors was mass media such as TV. This means environmental education in school is needed and mass media can be a very important tool for education. Secondly, as grades become higher, more students had knowledge on the endocrine disruptors. The difference between boys and girls was not significant. Thirdly, most students recognized endocrine disruptors as a dangerous material. However, they had an optimistic view on the possibility of resolving the environmental problems using science and technology in the future. Lastly, the scores of environmentally sound behavior was not highly correlated to those of knowledge. This means that in current environmental education system, more knowledge on the endocrine disruptors do not ensure more environmentally-correct behavior. These survey results show that environmental education on the endocrine disruptors should be constructed to induce correct behavior. That is, environmental education from now on has to be conducted to change the behavior of student as well as to increase knowledge.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.05a
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• pp.181-182
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• 2003

Exposure to some synthetic environmental chemicals and their metabolites cause reproductive problems in a variety of vertebrate via endocrine mechanisms. However, in most cases, the link between these compounds and adverse effects on humans, fish, and wildlife has not been established, which necessitates a closer look at the molecular, functional, and clinical implications of these chemicals in the environment. Calbindin-D9k (CaBP-9k) is a member of a largo family of intracellular calcium binding proteins that have high affinities for calcium. It was reported that the estrogen level of uterus affected the expression of the CaBP-9k gene in rat uterus. We examined the dose-dependent CaBP-9K gene expression in the uterus for three-days injection of methoxychlor (HC) in the overectomized immature rats and the relation with uterotrophic response of the compoundsand compared the responses induced by MC according to the route of administration.

• Applied Microscopy
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• v.26 no.4
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• pp.421-430
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• 1996

The endocrine cells in the midgut epithelium of the Japanese cockroach, Periplaneta japonica were observed by the light and electron microscopy. The midgut epithelium of the last instar larva and adult cockroach consisted of principal columnar cells, regenerative cells, and secretory granular cells. Midgut endocrine cells were positioned basally as a cone-shaped single cell in the epithelium or underneath the regenerative crypt cells. When midgut epithelium grows and the cell composing it transforms, between the endocrine cells and regenerative cells were made desmosome type junction and large vesicular shaped stretches of loose contact. The endocrine cells were characterized by a clear cytoplasm with abundant Golgi complex and numerous secretory granules. The secretory granules in the cell were spherical and electron dense with their diameter of $200{\sim}400nm$. The secretory granules have been observed as discharged by exocytosis on the basal and lateral side of the cell.