• Imaging Science in Dentistry
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• v.30 no.3
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• pp.169-181
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• 2000

Purpose: To investigate the expression of bone morphogenetic protein (BMP)-2/4 during eary tooth development after irradiation and calcium-deficient diet. Materials and Methods: The pregnant three-week-old Sprague-Dawley rats were used for the study. The control group was non-irradiation/normal diet group (Group 1), and the experimental groups were irradiation/normal diet group (Group 2) and irradiation/calcium-deficient diet group (Group 3). The abdomen of the rats at the 9th day of pregnancy were irradiated with single dose of 350 cGy. The rat pups were sacrificed at embryonic 18 days, 3 days and 14 days after delivery and the maxillae tooth germs were taken. The tissue sections of specimen were stained immunohisto-chemically with anti-BMP-2/4 antibody. Results: At embryo-18 days, immunoreacivity for BMP-2/4 of the Group 1 was modetate in stratum intermedium of dental organ and weak in dental papilla and dental follicle, but that of Group 2 was weak in cell layer of dental organ, and no immunoreacivity was shown in dental papilla and dental follice of Group 2 and in all tissue components of the Group 3. At postnatal-3 days, immunoreacivity for BMP-2/4 of the Group 1 was strong in cell layer of dental organ, odontoblasts and developing alveolar bone, but that of Group of 2 and Group 3 was weak in odontoblasts and developing alveolar bone. At postnatal-14 days, immunoreacivity for BMP-2/4 of the Group 1 was strong in newly formed cementum, alveolar bone and odontoblasts, but that of Group 2 was weaker than that of Group 1. In the Group 3, tooth forming cell layer showed weak immunoreactivity, but other cell layers showed no immunoreactivity. Couclusion : The expression of bone morphogenetic protein (BMP)-2/4 during early tooth development was disturbed after irradiation and calcium-deficient diet.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.704-709
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• 2006

Ectopic eruption should be understood as a change in the course of the normal eruption path of a dental bud at any moment in its origin. Transposition is a unique and extreme form of ectopic eruption. The treatment for ectopic eruption and transposition is various from simple observation to surgical exposure and orthodontic traction, according to direction of erupting tooth degree of developing root apex and eruption space etc. Autotransplantation is transplantation of tooth from one area of the mouth to another in the same individual or is moving a eruption tooth into extraction socket or surgically prepared socket, and autotransplantation is considered as a treatment of choice for the ectopic eruption when orthodontic traction is unable or when tooth movement is limited. These cases which were treated with autotransplantation of maxillary lateral incisor and maxillary canine were reported, and good esthetic and functional result were induced.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.4
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• pp.438-445
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• 2020

Taurodontism is an anomaly characterized by a long and broad pulpal cavity and consumed apical location of the furcation area. This study aimed to determine the prevalence of taurodontism in deciduous molars based on digital panoramic radiographs of children. The study was performed on a sample of panoramic radiographs taken from 2,473 Korean children who visited the department of pediatric dentistry, Yonsei University Dental Hospital between Nov. 2005 and Mar. 2018. Taurodontism was mainly categorized by Daito's method. Using panoramic radiographs, taurodontism was also categorized into mesotaurodontism, hypotaurodontism, and hypertaurodontism. Mesotaurodontism was the most prevalent type. A total of 2,473 panoramic radiographs were evaluated. The prevalence of taurodontism was 5.7% in general, 51.5% in the left quadrant, 48.5% in the right quadrant, 6.3% in the maxilla, and 93.7% in the mandible. The distribution of taurodontism stratified by gender showed a higher prevalence in males. This is a comprehensive study on the prevalence of taurodontism in children using the largest sample size to date.

• Journal of Environmental Health Sciences
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• v.21 no.1
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• pp.68-73
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• 1995

This study of culturing testicular cell types in vitro has potential to be an invaluable tool for assessing the mechanisms of testicular toxicity, especially those of intragonadal interaction and spermatogenesis. Combined with the Sertoli/germ cell cultures, Leydig cells provide comprehensive and detailed information on the action of testicular toxicants at the level of the testis. Sertoli/germ cell were isolated and incubated well in vitro from 20~30 g rats and Leydig cells from 250~300 g rats. The Sertoli cells isolated from the testis of the SD rats grew into monolayer on about the 2nd~3rd day of culture, an appreciable cell increment being observed between the 4th~5th day. The Leydig cells isolated from the testis of the SD rats grew into a monolayer on about the 3rd-4th day of culture, an appreciable cell increment being observed between the 5th-7th day. These results suggest that Sertoli and Leydig cells can be cultured as a male fertility evaluation method alternative to the in vivo/conventional fertility test method and further study for the physio-chemical determination is needed.

• Parasites, Hosts and Diseases
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• v.26 no.1
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• pp.9-14
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• 1988

In an attempt to determine the susceptibility of inbred golden hamsters(Mesocricetus auratus) to the experimental infection with Clonorchis sinensis, twenty-five hamsters were divided into 5 groups and administered orally 5, 10, 20, 30 or 50 metacercariae each. The hamsters were killed on the 45th day after infection. The adult flukes were recovered from all hamsters. The overall recovery rate for the fluke was 57.9% with the range of 48.4% to 92.0%. As the number of the metacercariae given increased, a porportionate decrease in the recovery rate was found, the prepatent period of the fluke in the hamster varied from 15 to 17 days, with the average of 16 days. No significant differences in the development of the flukes were observed. Egg production expressed by EPG, increased step by step as the time elapsed. However, a tendency of decreasing egg laying capacity was observed with the increase of worm burden. It is suggested that the hamster is a suitable final host of C. sinensis.

• Korean journal of applied entomology
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• v.34 no.2
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• pp.106-111
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• 1995

This study was carried out to investigate the effect of mass trapping with synthetic sex pheromone on seasonal occurrence of, the Beet amyworm (BAW) Spodoptera exigua, and on suppress of their density in Chonnam province from 1992 to 1994. Adult males of BAW were colllected by the trap from early through early November. The numbers began to increase abruptly from early July, and forming three peaks on mid July, early August and early September. Yearly occurrence and the area damaged by the BAW varied in relation to weather condition. Especially, low temperature and heavy rainfall in August 1993 seems to have affected to reduce the BAW population. The pheromone trap attracted higher numbers (1.5~2.3 times) of BAW adult than ordinary light rap. And the BAW population in vinyl hose was noticeably reduced when more than 10 pheromone traps were operated per 330$\m^2$ of vinyl house.

• Korean journal of applied entomology
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• v.35 no.3
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• pp.205-208
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• 1996

Psylla pyricola population from Suwon($37^{\circ}$16' N) begins to enter diapause by exposure to a photoperiod of 14hr light. Over 93% of adults were induced to enter diapause when exposed to 13hr loght period, and at 18 and $25^{\circ}C$, the critical photoperiod was not influenced. When the photoperiod was switched during the nymphal stage from 16L to 10L, no morph change was occurred in the 4th and 5th instars. Average number of eggs laid per female was 486.2 in winter form adult and 387.2 in summer form adults, and average oviposition periods were 34 and 24 days, respectively.

• Development and Reproduction
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• v.5 no.2
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• pp.93-100
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• 2001

Precise mechanism by which the fetus can escape from mother's immune rejection is not well understood yet over the last 50 years. The clarification of immune mechanism at the feto-maternal interface is very important, because this can be a common pathogenesis of various pathologic conditions including spontaneous abortion, habitual abortion fetal growth restriction preeclampsia, implantation failure after assisted reproductive techniques, and fetal death. In this review, current hypothetical contents were described with the priority of importance: 1) The center of this mechanism is cross-talk between the expression of HLA-C, E, G on the extravillous cytotrophoblasts and their receptors on decidual NK cell, 2) immunomodulation, 3) innate immunity is the main immunologic mechanism, 4) various mechanisms besides HLA system(eq. complement) may be associated. The overall balance of immunomodulation among these mechanisms should result in the outcome of each pregnancy. Further researches regarding the regulation of HLA system, roles of cytokines, complements should be followed in the future.

• Journal of Preventive Medicine and Public Health
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• v.19 no.1 s.19
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• pp.123-129
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• 1986

Fetal weight data from 84 litters of Sprague-Dawley rats were statistically analyzed for the effect of position in the uterine horn on fetal weight. The standard score obtained from the mean weight and standard deviation of all fetuses in a uterine horn were studied for position effect. In control group, the heaviest fetus occupied the middle position with a progressive decrease in weights toward the ovarian and cervical ends of the horn. But the effect related to position for the fetal weight was not statistically significant. In contrast, rats acutely or chronically exposed to carbon monoxide showed statistically significant positional differences of fetal weight within the uterine horns. The findings that the intrauterine position effect on fetal weight which is not signicant in control group may act one of confounders at the situation of transplacental toxicological studios.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.1
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• pp.50-60
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• 2012

This study was carried out to evaluate the ecotoxicological effects of Alum and Ferric chloride on the population of Eisenia fetida in vermicomposting of sewage sludge. Using contact filter toxicity test, it was shown that LC50 of Alum and Ferric chloride on adult Eisenia fetida were 457.4 mg $kg^{-1}$ and 1,665.2 mg $kg^{-1}$, respectively,which meant Ferric chloride had much higher acute toxicity on earthworm than Alum. Alum didn't affect on cocoon production, hatchability and number of hatched larvae of Eisenia fetida. Ferric chloride didn't have any efects on number of hatched larvae per cocoon, but reduced cocoon production and hatchability. Larval density of next generation was reduced by the food containing Alum and Ferric chloride. Above results indicated that the Alum and Ferric chloride could be one of the hazardous materials that made extinction of earthworm population when the sewage sludge treated with Alum and Ferric chloride was supplied to the earthworms.