• Korean Journal of Veterinary Service
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• v.17 no.2
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• pp.122-129
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• 1994

Teratogenic effects of diazinon were assessed morphologically and cholinergic blocking agents. Diazinon at doses ranging from 25 to 2000 ug /egg, was Injected on day 3 of incubation. TD50s were different for the various teratogenic signs (wry neck, micromelia, abnormal feathering, abnormal beak and curled claws). The threshould dose for wry neck was higher than threshould dose for other signs； 40 ug/egg produced substantial micromelia, abnormal feathering. abnormal beak and curled claws, but gave no signs of wry neck. In contrast to the teratogenic doses, the LD50 of diazinon was very high (above 2000 ug /egg). One of the characteristics of diazinon-induced teratogenesis was reduced body weight (78.7％) and body length (73.8%). Maximal teratogenic effects, scored as signs of retarded growth, wry neck micromelia, abnormal feathering, abnormal beak, and curled claws, were produced when the insectcide was administered on the third or fourth day. The threshold dose for type II teratogenic signs(such as wry neck and short neck) was higher than for type I (such as micromelia and abnormal feathering). Morphological studies, using atropine and gallamine, suggested that nicotine but not muscarinic receptors may be involved in the mechanism of diazinon induced type II malformations.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2000.11a
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• pp.78-80
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• 2000

A new murine TGF-$\beta$ family member, myostatin(growth/differentiation factor-8) is expressed specifically in developing and adult skeletal muscle and may be a negative regulator of skeletal muscle development. This study aims at characterization and identification of genomic organization of chicken myostatin gene. In thi study, we identified the genomic organization and sequence of chicken myostatin gene. Results of RT-PCR and Northern blots from various tissues showed different mRNA expression levels in developmental stages of chick embryos and demonstrated strong expression of myostatin mRNA in skeletal muscle. These facts suggest that chicken myostatin gene would play an important role not only in skeletal muscle cell but also in other tissues.

• Animal cells and systems
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• v.1 no.1
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• pp.63-69
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• 1997

We have previously reported that NF-kB is involved in the regulation of nitric oxide synthase gene expression during differentiation of chick embryonic myoblasts. However, how NF-kB is timely activated during myogenesis remains elusive. One of the most prominent events in myogenesis is myoblast membrane fusion, which is accompanied with massive cytoskeletal reorganization. Here we show that the activity of NF-kB markedly increases in L6 rat myogenic cells that have just initiated morphological changes by treating nocodazole, a microtubule-disrupting agent. Furthermore, the induction of NF-kB activation was closely correlated with the myoblast fusion. In addition, a variety of agents that disrupt microtubules stimulated the myoblast fusion as well as the induction of NF-kB activation. In contrast, taxol, a microtubule-stabilizing agent, suppressed the induction of NF-kB activation and inhibited spontaneous differentiation of L6 cells as well. In addition, we found that the NF-KB in the cells consists of p50/p65 heterodimers. These results support the idea that reorganization of microtubule at early stages of differentiation plays a role as a signal for NF-KB activation during myogenesis.

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.575-595
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• 1997

Replacement resorption is followed by the delayed replantation of an avulsed tooth. Currently no effective treatment is substantiated for replacement resorption. The purpose of this study was to investigate the effect of stannous fluoride, bisphosphonate (etidronate disodium) and gallium nitrate, which have been shown to reduce dentin resorption, on human dentin. Osteoclasts were collected from tibeas of chick embryo. The cells were well agitated to prevent adhesion and seeded onto the sliced human dentin wafers which had been soaked in either culture media (control), or several different concentrations of stannous fluoride, etidronate disodium (l-hydroxyethylidene -1,1-bisphosphonate disodium), and gallium nitrate. Resorption was measured by counting the number of resorptive pit produced by the cells. Results are as follows. Stannous fluoride and etidronate disodium showed statistically significant reduction of dentin resorption(p<0.05) but the effect of stannous fluoride seemed to be its high cytotoxicity. Etidronate disodium did not show cytotoxicities in all experimented concentrations. Gallium nitrate did not show differences in resorption either between different concentrations or from the control group.

• Nuclear Engineering and Technology
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• v.6 no.2
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• pp.73-79
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• 1974

The preparation method of the mortar-plastic composites(M P C) were studied with styrene, methyl methacrylate and vinyl acetate as monomers. Radiation, thermal-catalytic and radiation-catalytic methods were used as curing methods. Almost all of the above monomers and methods were possible to use for preparing M P C Although thermal-catalytic method was excellent to get M P C in a short time, the tensile strength of the product was less than those obtained by radiation method. It was possible to prepare the M P C which included up to about 10% plastics and was strengthened about ten times on the properties of acid resistandes and tensile strength comparing with the control. The improvement of the properties is much superior to concrete-plastic composite(C P C).

• The Korean Journal of Zoology
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• v.24 no.4
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• pp.189-200
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• 1981

Drastic alterations in myogenesis could be induced by ultraviolet irradiation of the myogenic cells derived from 12 day old chick embryo skeletal muscle. The effects of irradiation on various aspects, including cell division, transformation to myotubes, and morphology of myoblasts and myotubes, were examined. Irradiated cells were smaller in size, and only few cells transformed resulting in smaller size of myotubes with a narrow width. Both the inhibiting actions to cell division and to fusion were more striking when irradiated at earlier stages after plating. As well, cell division and fusion were inhibited more effectively with increasing UV dose and excessive amount caused cell death. A lowering cell density was thought to account for the decrease in myogenesis and possible reasons for the decrease in the capacity for fusion were discussed in view of the results presented in this report and of the findings from other laboratories.

• The Korean Journal of Zoology
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• v.35 no.2
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• pp.161-172
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• 1992

In the short-term treahent of 12-0-tetradecanoylphorbol-13-acetate (TPA) or platelet-derived growth factor (PDGF), the'Wh and PDGF induced the Protein Kinase C (PKC) activation and migration from the cytoplasm to the peripheral nulcear membrane. And the activated PKC which was directly or indirectly stimulated by TPA or PDGF Phosphorylated many kinds of PKC's targeting proteins and induces various biological responses. Especially, the cytoplasmic PKC was phosphorylated within 1 hr and 10 min by TPA-and PDGF-treahent respectivelv. In the long-term treatment of TPA or PDGF, both of them induced the down-regulation and translocation of PKC in the mvoblasts. The down-regulation of PKC isozyrnes, the pattern of PKC I and ll was similar to the PKC 111 isozpnes in the cytoplasm. But in the nucleolus, the TPA did not induce and down-regulation or the inhibition of the immunoreactivity of PKC III antibody. This investigation indicates that each isozvmes of PKC mal be performed the different effects to the down-regulation of the cytoplasm or nucleolus. And douvn-regulated myoblasts contained low immunoreactivity of PKC antibodies.

• Korean Journal of Veterinary Research
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• v.45 no.1
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• pp.71-74
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• 2005

Pseudomonas aerusinosa infection was diagnosed in broiler chicks, and was submitted to the National Veterinary Research and Quarantine Service in Korea. The total mortality rate was about 1,500 birds out of 22,000 broilers. Clinically, affected birds showed clinical signs including depression and anorexia with lameness and trembling of the leg. At necropsy, the dead broilers appeared to have omphalitis, yolk sac infection, fibrinous epicarditis, and fibrinous exudates in liver with swollen hock joint. Microscopically, there were multiple necrotic foci in the liver, fibrinous exudates in the heart, and infiltration of heterophils into the joint spaces of the hock joint. Pseudomonas aerusinosa was isolated from the heart, liver and hock joint, and the isolate was named P-200. In effort to estimate the virulence of P-200, 1-day-old chicks were challenged intramuscularly and intrayolksacally with the isolate. On the basis of mortality rate, the isolate P-200 was found to be highly virulent. This is the first report of an occurrence of Pseudomonas aerusinosa infection in broilers in Korea.

• KSBB Journal
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• v.19 no.2
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• pp.125-131
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• 2004

Various medicinal plants were examined as resources for antidiabetic biomaterials, using an oriental medicinal database. The prescription frequency and dosage of medicinal plants in 131 antidiabetic prescriptions were analyzed. Total prescription score of each medical plant was summed up from prescription table and score table. High-scored medicinal plants have been widely studied in the previous research on the diabetic treatment. Consequently, dangui, hwangryun, maekmoondong, ginseng, chick, saengjihwang, omija, bokryung, Jimo and cheonhwaboon were assumed to have high antidiabetic activities.

• The Korean Journal of Zoology
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• v.33 no.2
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• pp.158-165
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• 1990

Proteolytic activity of calpain was found to increase as myoblast fusion proceeds. At 60 hr after cell seeding, lis activity reached to a maximal level and then slighdy decreased thereafter. Similarly, the protein level of calpain reached to a maximal level just proir to the initiation of fusion and remained elevated upon prolonged culture as analyzed by immunoblol using anti-calpain antiserum. These results suggest that the synthesis of calpain is regulated during myogenesis and its proteolytic activity may be related with the process of myoblasts fusion.