• The Korean Journal of Zoology
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• v.37 no.2
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• pp.255-261
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• 1994

Recombinant human pBrathyriod hormone related peptide (1-341 (rhPTHrP) has been known to stimulate bone resorption in intact bone tissue culture system. Osteoclast has been known as a primary responsible cell for bone resorption. To examine the effect of rhPTHrP on this cell, we employed disaggregated rat osteodast culture. As a result, we found that rhPTHrP sisnificBntly elevates both the number and total area of resorbed pits in this culture. On the other hand, the conflicting results between disagsregated rat osteoc13st culture and Ca2+-deficient hen osteoclast culture system have been a big obstacle for the progress of bone research. To verify the differences between rat 3nd chick osteoclast system, we performed the same experiment using chick embryonic osteoclast. Since the similar results were obtained from the disaggregated chick osteoclast culture, the discrepancy between chick and rat osteoclast culture study seemed to be due to the difference in culture method, rather due to the species-difference.

• Journal of The Korean Society of Clinical Toxicology
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• v.5 no.2
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• pp.131-134
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• 2007

The emergence of anticoagulant rodenticides in the 1950's resulted in an epochal reduction in the use of all other agents. It is estimated that anticoagulant rodenticides constitute 95 percent of all rodenticides now in use. However, the advent of rodent resistance to these agents has led to a return to use of some other non-anticoagulant types of rodenticides. Older non-anticoagulant rodenticides have been stored in basements, garages, and barns and are still in use in some regions of the United States and in other countries. We report a case of non-anticoagulant rodenticide (beta-fluoroethyl acetate) poisoning.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1643-1645
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• 1994

It has been reported frequently that damage to underground electric power cable was brought about, due to attack by Insect such as termite (white-ant) and by rodent such as rat, in tropical and semitropical areas. Among these cable damages, we are likely to describe the damage to cable by termites as causing the severe trouble in cable operation and to solve this trouble with termite-proof method regarded as the most effective and economical one. This report covers our experiences of manufacturing the cable for anti-termite purpose and its intrinsic properties in cable operation.

• Biomedical Science Letters
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• v.9 no.2
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• pp.99-103
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• 2003

Hantavirus are rodent-borne RNA virus that belongs to the family Bunyaviridae. Those viruses persistently infect a variety of rodents, and are transmitted by aerosols of their urine, feces and saliva. Antibody titers of sera obtained from normal laboratory rodents against hantaviruses were investigated by indirect immunofluorscence antibody technique (IFA), Seroconversion rates of normal laboratory rodents showed higher in rats than that from hamster and mongolian (M). gerbil. Theses rates of normal laboratory rodents also showed higher in titers against puumala virus (PUUV) than in hantaan (HTNV) and seoul virus (SEOV). We are concerned about infections caused by hantaviruses, especially by PUUV, occurred in laboratory rodents.

• Journal of Korean Neurosurgical Society
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• v.65 no.2
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• pp.161-172
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• 2022

Although technological advances and clinical studies on stem cells have been increasingly reported in stroke, research targeting hemorrhagic stroke is still lacking compared to that targeting ischemic stroke. Studies on hemorrhagic stroke are also being conducted, mainly in the USA and China. However, little research has been conducted in Korea. In reality, stem cell research or treatment is unfamiliar to many domestic neurosurgeons. Nevertheless, given the increased interest in regenerative medicine and the increase of life expectancy, attention should be paid to this topic. In this paper, we summarized pre-clinical rodent studies and clinical trials using stem cells for hemorrhagic stroke. In addition, we discussed results of domestic investigations and future perspectives on stem cell research for a better understanding.

• Journal of Veterinary Science
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• v.21 no.1
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• pp.1.1-1.4
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• 2020

Tumor incidence in wild mammals is reportedly very low. Wild nutria, a large rodent, is known to carry many infectious diseases, but rarely exhibits neoplastic diseases. We necropsied a male wild nutria and found a large nodular mass in the left inguinal region, adjacent to the penis. Histopathologically, the mass was diagnosed as preputial gland adenoma. Spontaneous preputial gland adenomas are extremely rare in all animals. Moreover, reports of tumors in nutrias have been limited to adenocarcinomas of the lungs and uterus, as well as subcutaneous fibromas. Here, we describe preputial gland adenoma in a wild nutria.

• Korean Journal of Transplantation
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• v.28 no.3
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• pp.113-120
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• 2014

Two-signal models are useful in explaining various types of immune responses. In particular, secondary, so-called costimulatory, signals are critically required for the process of T-cell activation, survival, differentiation, and memory formation. Early studies in rodent models showed that targeting T-cell costimulatory pathways elicits immunological tolerance, providing a basis for development of costimulatory therapeutics in allograft rejection. However, as the classic definition of T-cell costimulation continues to evolve, simple blockade of costimulatory pathways has limitations in prevention of allograft rejection. Furthermore, functions of costimulatory molecules are much more diverse than initially anticipated and beyond T cells. In this mini-review, we will discuss CD137-CD137L bidirectional signals as examples showing that two-signals can be applicable to multiple phases of immune responses.

• Korean Journal of Environment and Ecology
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• v.34 no.3
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• pp.198-206
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• 2020

The purpose of this study was to investigate the damage caused by rodents in the area around Seseokpyeongjeon in Jirisan National Park and identify suspected perpetrating species by analyzing rodent excrement found near the damaged trees. Damaged trees were surveyed regardless of species of trees in the exploration trail in the target site where visual observation was possible. Sequencing analysis of mitochondrial DNA Cyt-b was performed on rodent excrement around the damaged trees to identify the perpetrating species. A total of 52 trees were damaged by rodents, and they were all identified to be Korean Fir (Abies koreana) and were concentrated in places where Korean Fir formed communities with high density. A total of 40 Korean Fir over 1.5 meters high were surveyed, and only the affected branches, not the whole tree, were found to be withered in 39 of them. A total of 12 Korean Fir under 1.5 meters high were surveyed, and 7 of which were found to have been completely withered, indicating that relatively young trees were more vulnerable to withering. The genetic sequencing analysis of excrement confirmed that the species that perpetrated the Korean Fir was Craseomys regulus.

• Development and Reproduction
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• v.11 no.1
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• pp.13-20
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• 2007

In all female mammals, reproductive system is one of the first biological systems to show age-related decline. Female mammals in reproductive aging, though the phenomena is somewhat species-specific, start to show declining fertility and changes of numerous physiological functions. This review will present a current information on the aging of the female reproductive hormonal axis and introduce three useful rodent models for studying this field. Middle age($8{\sim}12$ months old) in female rats and mice is comparable to the stage prior to the entry of menopause in human. In this period pulsatile and surge GnRH secretion from hypothalamus gradually attenuated, then reduced pulsatile and surge LH secretion is followed consequently. This age-related defects in GnRH-LH neuroendocrine axis seem to be highly correlated with the defects in brain signals which modulate the activities of GnRH neuron. Many researchers support the idea which the age-related hypothalamic defects are the main cause of reproductive aging, but some ovarian factors such as inhibin response also could contribute to the induction of reproductive senescence. Some rodent models are quite valuable in studying the reproductive aging. The follitropin receptor knockout(FORKO) mice, both of null and haploinsufficient state, could produce depletion of oocyte/follicle with age. Dioxin/aryl hydrocarbon receptor(AhR) knockout mice also show severe ovarian defects and poor reproductive success early in their life compared to the age-matched normal mice. Further studies on the reproductive aging will be a great help to evaluate the benefits and risks of hormone replacement therapy(HRT) and to improve the safety of HRT.

• Journal of Microbiology and Biotechnology
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• v.28 no.4
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• pp.645-651
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• 2018

The carcinogenicity of chemicals in the environment is a major concern. Recently, numerous studies have attempted to develop methods for predicting carcinogenicity, including rodent and cell-based approaches. However, rodent carcinogenicity tests for evaluating the carcinogenic potential of a chemical to humans are time-consuming and costly. This study focused on the development of an alternative method for predicting carcinogenicity using quantitative PCR (qPCR) and colon cancer stem cells. A toxicogenomic method, mRNA profiling, is useful for predicting carcinogenicity. Using microarray analysis, we optimized 16 predictive gene sets from five carcinogens (azoxymethane, 3,2'-dimethyl-4-aminobiphenyl, N-ethyl-n-nitrosourea, metronidazole, 4-(n-methyl-n-nitrosamino)-1-(3-pyridyl)-1-butanone) used to treat colon cancer stem cell samples. The 16 genes were evaluated by qPCR using 23 positive and negative carcinogens in colon cancer stem cells. Among them, six genes could differentiate between positive and negative carcinogens with a p-value of ${\leq}0.05$. Our qPCR-based prediction system for colon carcinogenesis using colon cancer stem cells is cost- and time-efficient. Thus, this qPCR-based prediction system is an alternative to in vivo carcinogenicity screening assays.