• Journal of Korean Society for Atmospheric Environment
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• v.8 no.1
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• pp.29-37
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• 1992

The risk of benzo(a)pyrene for cancer in the ambient air of Seoul was assessed by using the extrapolation methods. The average daily lifetime exposure of benzo(a)pyrene in the ambient air of Seoul was calculated at 6.97-24.30ng/$m^2$/day, which was based on the occurrence analysis of benzo(a)pyrene in the residential(Bull Kwang Dong) and traffic areas(Shin Chon) of Seoul. Using the dose scaling based on body surface area in comparisons of toxicity for extrapolation from animal to human and mathematical models from the high dose region, the low-dose risk was estimated. The response probabilities were estimated by the tolerance distribution models; Probit, Logit and Weibull model. They were consistent with the observed ones at experimental dose region. The unit risk estimates of these models were too low to be used. One-hit and multistage model to prove more conservative risk was selected. As a redult, the lifetime unit risk of benzo(a)pyrene for cancer and virtually safe dose were calculated; One-hit model provided the risk 2.8 $\times 10^{-7}$ and 3.4ng/$m^3$, respectively and multistage model provided 5.2 $\times 10^{-7}$ and 1.9ng/$m^3$ as the more conservatives. The lifetime excess risk estimates of benzo(a)pyrene for cancer were calculated at 0.37-1.30 persons/million persons by one-hit model and 0.69-2.41 persons/million persons by multistage model, which was considered in without virtual risk.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.2
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• pp.135-141
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• 2001

Recently, the consumption of soy products has been associated with low rates of hormone-dependent and hormone-independent cancers. Asians, who consume $20{\sim}50times$ more soy per capita than Americans, have lower incidence and death rates from breast and prostate cancer. Because soy contains the isoflavones genistein and daidzein (present as their glycosidic conjugates) at mg/g concentrations, it has been suggested that isoflavones might be acting as natural chemopreventive agents. During the 1980s several groups of investigators carried out experiments to test the effectiveness of soy in the diet in animal models of cancer. These studies reported a protective effect of soy; none showed that soy increased cancer risk. Genistein was shown to inhibit the growth of a wide variety of tumor cell types in culture. The purpose of this study was to evaluate the effects of genistein on the carcinogenesis induced by topical application of 0.5% 9, 10-dimethyl 1,2-benzanthracene (DMBA) on the hamster buccal pouch. 48 syrian hamsters were employed in this study, divided into experimental group and control. 24 animals (DMBA topical application group) had the right buccal pouch painted 3times weekly with 0.5% DMBA in mineral oil, 24 animals (genistein group) were supplied with 0.1mg genistein with DMBA topical application. 3 animals in the experimental group and control were sacrificed at serially each other week after experiments. Their buccal pouches were removed and routinely processed for microscopic examination. The results were as follows: 1. In DMBA topical application and genistein group, they showed carcinogenesis as time goes by experimental stage. 2. Genistein group was retarded in carcinogenesis related to the acanthosis, hyperkeratosis, epithelial dysplasia. 3. p53 immunohistochemical study showed that the p53 protein of genistein group was less expressed than that of the control group. Thus, it seems that genistein has chemopreventive effect on the carcinogenesis in the oral cavity, but further study is required to elucidate the anticancer mechanism of genistein.

• Imaging Science in Dentistry
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• v.52 no.1
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• pp.61-66
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• 2022

Purpose: This study aimed to compare the therapeutic effects of corticosteroid irrigations and normal saline irrigations in the early inflammatory state of the salivary gland. Materials and Methods: Adult male Wistar rats were divided into experimental (n=6) and control (n=3) groups. Inflammation was induced in the experimental subjects on both sides of the submandibular gland with ligation. After 14 days, both sides of the glands were de-ligated and retroductal irrigation using saline (n=3) and a corticosteroid (n=3) was performed on the left sides only. The controls (n=3) were used to normalize the gland state for the effects of diet and aging. Magnetic resonance imaging was performed to confirm inflammation and post-irrigation gland recovery by measuring relative signal intensity (SI). The glands were excised for histological examination. Results: All experimental animals showed inflamed glands with increased SI and subsequent recovery of the gland with decreased SI to varying degrees. The SI of the controls showed no significant changes during the overall period. The mean SI change of the irrigated gland was higher than that of the non-irrigated side, without a significant difference. The corticosteroid-irrigated glands showed a greater change in SI than that of the saline-irrigated glands. Histology revealed that inflammation was not observed in most of the irrigated glands, while mild to moderate quantities inflammatory cells were found in non-irrigated glands. Conclusion: Corticosteroid irrigation mitigated the early stages of salivary gland inflammation more effectively than normal saline.

• IMMUNE NETWORK
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• v.24 no.1
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• pp.9.1-9.21
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• 2024

The cytokine IL-7 plays critical and nonredundant roles in T cell immunity so that the abundance and availability of IL-7 act as key regulatory mechanisms in T cell immunity. Importantly, IL-7 is not produced by T cells themselves but primarily by non-lymphoid lineage stromal cells and epithelial cells that are limited in their numbers. Thus, T cells depend on cell extrinsic IL-7, and the amount of in vivo IL-7 is considered a major factor in maximizing and maintaining the number of T cells in peripheral tissues. Moreover, IL-7 provides metabolic cues and promotes the survival of both naïve and memory T cells. Thus, IL-7 is also essential for the functional fitness of T cells. In this regard, there has been an extensive effort trying to increase the protein abundance of IL-7 in vivo, with the aim to augment T cell immunity and harness T cell functions in anti-tumor responses. Such approaches started under experimental animal models, but they recently culminated into clinical studies, with striking effects in re-establishing T cell immunity in immunocompromised patients, as well as boosting anti-tumor effects. Depending on the design, glycosylation, and the structure of recombinantly engineered IL-7 proteins and their mimetics, recombinant IL-7 molecules have shown dramatic differences in their stability, efficacy, cellular effects, and overall immune functions. The current review is aimed to summarize the past and present efforts in the field that led to clinical trials, and to highlight the therapeutical significance of IL-7 biology as a master regulator of T cell immunity.

• Journal of Korean Dental Science
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• v.5 no.2
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• pp.48-53
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• 2012

Various ceramic implant systems made of yttria-stabilized tetragonal zirconia polycystal (Y-TZP) have become commercially available in recent years. A search of the literature was performed to assess the clinical success of dental Y-TZP implants and whether the osseointegration of Y-TZP is comparable to that of titanium, the standard implant material. No controlled clinical studies in humans regarding clinical outcomes or osseointegration could be identified. Clinical data were restricted to case studies and case series. Only 7 animal studies were found. Osseointegration was evaluated at 4 weeks to 24 months after placement in different animal models, sites and under different loading conditions. The mean bone-implant contact percentage was above 60% in almost all experimental groups. In studies that used titanium implants as a control, Y-TZP implants were comparable to or even better than titanium implants. Surface modifications may further improve initial bone healing and resistance to removal torque. Y-TZP implants may have the potential to become an alternative to titanium implants but cannot currently be recommended for routine clinical use, as no long-term clinical data are available.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.1
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• pp.123-130
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• 2014

The A-type lamin deficient mouse line ($Lmna^{-/-}$) has become one of the most frequently used models for providing insights into many different aspects of A-type lamin function. To elucidate the function of Lmna in the growth and metabolism of mice, tissue growth and blood biochemistry were monitored in Lmna-deficient mice, heterozygous ($Lmna^{+/-}$) and wide-type ($Lmna^{+/+}$) backcrossed to C57BL/6 background. At 4 weeks after birth, the weight of various organs of the $Lmna^{-/-}$, $Lmna^{+/-}$ and $Lmna^{+/+}$ mice was measured. A panel of biochemical analyses consisting of 15 serological tests was examined. The results showed that Lmna deficient mice had significantly decreased body weight and increased the ratio of organ to body weight in most of tissues. Compared with $Lmna^{+/+}$ and $Lmna^{+/-}$ mice, $Lmna^{-/-}$ mice exhibited lower levels of ALP (alkaline phosphatase), Chol (cholesterol), CR (creatinine), GLU (glucose), HDL (high-density lipoprotein cholesterol) and higher levels of ALT (alanine aminotransferase) (p<0.05). $Lmna^{-/-}$ mice displayed higher AST (aspartate aminotransferase) values and lower LDL (lowdensity lipoprotein cholesterol), CK-MB (creatine kinase-MB) levels than $Lmna^{+/+}$ mice (p<0.05). There were no significant differences among the three groups of mice with respect to BUN (blood urea nitrogen), CK (creatine kinase), Cyc C (cystatin C), TP (total protein), TG (triacylglycerols) and UA (uric acid) levels (p>0.05). These changes of serological parameters may provide an experimental basis for the elucidation of Lmna gene functions.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.2
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• pp.118-125
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• 2010

Background and Purpose: Bone metastases rarely occur in patients with oral squamous cell carcinoma (OSCC), so the molecular mechanisms of bone metastasis of OSCC remains unclear. Studies with animal models allow progresses in understanding the molecular events for bone metastasis and provide new targets for therapy. So we tried to establish a murine model for bone metastasis of oral squamous cell carcinoma. Materials and Methods: Human OSCC cells (KB cell line) were xenografted to nude mice via direct inoculation into the tibial marrow. Mice with tibial tumors were sacrificed once a week, until seven weeks after the injection of human tumor cells. Growth of tibial tumors were observed by histology. Expression of TGF-$\beta$ and CXCR-4 in bone OSCC (experimental) and subcutaneous tumor (control) was also evaluated by immunohistochemical staining. Results: Bone OSCC was successfully induced by intra-tibial injection of KB cells. Tumor mass was developed in the marrow tissues of tibia and finally invade the endosteum of tibia. Immunohistochemical staining showed higher expression of TGF-$\beta$ in bone tumors than in subcutaneous tumors. Conclusion: A murine model of bone metastasis of OSCC was suggested that imitated the clinical findings of distant vascular metastasis. This bone tumor model should facilitate understanding of the molecular pathogenesis of OSCC bone metastasis, and aid in the developement of treatment strategies against OSCC bone metastasis.

• Journal of Korean Biological Nursing Science
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• v.10 no.2
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• pp.176-183
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• 2008

Purpose: The purpose of this study was to identify the effect of Environmental Enrichment (EE) on improvement of motor function in animal models of Parkinson's Disease. Methods: Male C57BL6 mice weighing 25-30 g, at the age of 12 wks were used in this study. The animals were injected MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin, 20 mg/kg in saline, i.p.) 4 times a day at every 2 hr, and raised in EE cage for 14 days. On day 14, after behavior test, all mice were sacrificed for immunohistochemistry. All values were expressed as means$\pm$S.E.M. Statistical significance was evaluated using a one way ANOVA followed by Sheffe test. Results: There was a significant difference between the experimental group and the control group in the behavior test. Also EE significantly reduced of TH positive cell loss in Substantia nigra pars compacta as compared to the result of MPTP treatment. Conclusion: Based on these findings, it is reasonable to assume that the environmental enrichment prevents dopaminergic neuronal loss and improves disarrangement of motor function and behavioral disability induced by MPTP.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.05a
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• pp.290-296
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• 2005

This study was carried out to develop the efficient freeze concentration process of milk through controlling the recrystallisation phenomena of ice. Freeze-concentration was progressed with multi-stage freeze concentrator and there was artificial temperature control to induce recrystallisation phenomena. In each stage of freeze concentration process, the regular recrystallisation time was fixed as 1, 2, 4 and 8 hr to compare the solute increment, yield, brix and ice-crystal size among experimental conditions. Higher concentration as total solids was observed due to the elapse of recrystallisation time, and the maximum total solids in final products: 32.67% was obtained at the ripening time of 8 hr in two-stage process. This result was excessively high concentration comparing to the existing researches and presented the possibilities of milk freeze concentration in the dairy industry, The results of brix and ice-crystal size showed the direct correlation with the recrystallisation time that meant the increased processing time showed the increment of brix and ice-crystal size. Obtained results were numerically modelled to predict the progress of concentration in the industrial process and all of them had fairly high R2 of determination. Therefore, we regarded that these numerical models could be utilized for the development of efficient technology in industrial freeze concentration process.

• Korean Journal of Cleft Lip And Palate
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• v.11 no.2
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• pp.49-58
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• 2008

The development of fetal surgery has led to promising options for many congenital malformations, such as congenital diaphragmatic hernia (CDH), obstructive uropathy, twin-to-twin transfusion syndrome (TTTS), and sacrococcygeal teratoma. However, preterm labor (PTL) and premature rupture of membranes continue to be uniquitous risks for both mother and fetus. To reduce maternal morbidity and the risk of prematurity, minimal access techniques were developed and are increasingly employed recently. Lift-threatening diseases as well as severely disabling but not life-threatening conditions are potentially amenable to treatment. Recently, improvement of video-endoscopic technology has boosted the development of operative techniques for feto-endoscopic surgery, which has been demonstrated to be less invasive than the open approach. Fetal surgery for repair of cleft lip and palate, a congenital anomaly which is not life threatening, is inappropriate until such time that the benefits are shown to outweigh the risks of both the procedure itself and preterm delivery. Further animal studies will be needed before intrauterine surgery for humans should be considered. For the better understanding of recent techniques and complications associated with fetal intervention of congenital facial defect patients, we reviewed recent related articles about the current knowledge and new perspectives of experimental fetal fetal surgery in the cleft lip and palate defects.