• Advances in pediatric surgery
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• v.13 no.2
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• pp.135-143
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• 2007

Biliary atresia (BA) is an uncommon neonatal surgical disease that has a fatal outcome if not properly treated. The survival rates of the patients with native liver after Kasai's operation in countries outside Japan are not so good. We reviewed the results of 22 cases of biliary atresia treated in Kosin University Hospital between October 1987 and March 2001. There were 13 males and 9 females aged from 21 to 106 days (mean 52 days). There were 3 cases of Type I (13.6%), and 3 of Type II (13.6%), and 16 Type III (72.7%). The operative methods were resection of the common bile duct remnant and cyst followed by Roux-en-Y hepaticojejunostomy in 3 cases for Type I BA; Kasai I in 15 cases, Kasai II in 1 case, and Ueda's operation in 3 cases for Types II and III BA. There was no death within the first 30 days after operation. We were able to follow 21 of the 22 patients (95.4%) for more than 5 years. The actual 5 year survival rate (YSR) was 40.9%. One Type I case received a living-related liver transplantation at 6 years of age because of the multiple intrahepatic stones and liver cirrhosis. Five YSR after biliostomy group (Kasai II and Ueda op.) was 75 % (3/4) while that of Kasai I was 20% (3/15). One case had no bile duct in the resected fibrotic plaque on microscopic review and died 8 months after Kasai I operation, would have been a strong candidate for early liver transplantation. From the above result, our conclusions are as follows; (1) early liver transplantation should be considered for cases of no bile duct after pathologic examination of the resected specimen, (2) measures to prevent postoperative cholangitis and prevention of postoperative liver cirrhosis are needed, (3) liver transplantation program should be available for failed cases.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.2
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• pp.106-113
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• 2011

The object of this clinical study was to evaluate the short-term outcome of modified resin-bonded fixed partial dentures which utilizes the original tooth undercuts and different path of insertion of components. Materials and methods: 71 units of modified RBFPDs that were used in 21 patients at the Department of Prosthodontics, College of Dentistry, Yonsei University were evaluated. The follow-up period was up to 25 months, the mean being 7 months. Survival rate, mobility, percussion, probing depth, bleeding on probing, plaque index was recorded and radiographs were taken to monitor alveolar bone loss. Results & Conclusion: Within the limits of this short term retrospective study, it was concluded that: 1. No mechanical failure such as debonding or fracture of the framework was found during the follow-up period. 2. The periodontal apparatus was stable and no clinical change was observed after prosthetic treatment. 3. No significant marginal bone loss was found in the radiographic evaluation.

• Journal of Korean society of Dental Hygiene
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• v.4 no.1
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• pp.65-79
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• 2004

There are two purposes in this study. The first one is to collect some oral health information through the investigations upon the oral health care of Korean adults. Referring to the result of the investigation. I wanted to furnish fundamental data with oral health education for each age and with a publicity booklet editing. That is the second purpose of this research. Among the people who visited Seo-gu Public Health Center in Kwang-ju, 207 people answered the questionnaires. There were 86 men and 121 women from the 20-aged to the 59- aged. The questionnaires covers knowledge aquisition path for dental caries prevention, the cognition degrees for the causes of dental caries and its prevention, the cognition degrees for the causes of periodontal disease and its prevention, the degrees for oral health methods, and the importance of oral health. The conclusions are as follows; 1. The cognition degree for dental caries prevention: The cognition for pit and fissure sealant was appeared most highly in thirties by 85.3%. but 62.1 % in fifties was answered, "Never heard". The cognition degree for fluoride application was appeared most highly in thirties by 73.5%. and the cognition degree for water fluoridation was most highly in forties by 54.2%. 2. The knowledge for pit and fissure sealant was acquired mostly through dental hospital in every age by 54.2%. 3. The knowledge for fluoride application was learned mostly through dental hospitals in twenties and thirties by 32.7%. and mostly through TV or radio health programs in forties and fiftieseach by 35.7% and 50.0%. 4. The knowledge for water fluoridation was acquired through TV or radio programs in all ages such as twenties. thirties. forties and fifties. Its rate was 57.8%. 5. The cognition degree of the cause of dental caries: 53.1 % of all ages think that dental caries can most frequently be caused by being lack of toothbrushing. 6. The cognition degree of the cause of periodontal disease: 58.5% people of all ages think that both dental plaque and calculus might be the main cause of periodontal disease. 7. The cognition degree of dental caries prevention: 72.8% people think that dental caries can be prevented by right tooth brushing method. and 8.7% people think that they can be prevented by scaling. However, 10.7% people of them were not interested in dental caries prevention. 8. The importance of oral health: 35.3% people think that teeth health is the most important, and 63.8% people think oral health is one of the most important health problems. Forties answered that tooth health was the most important thing, and fifties. thirties and twenties followed in the order. 9. The cognition for oral health maintenance: all ages(twenties. thirties. forties. and fifties) answered that right toothbrushing method was the best way to keep oral health by 69.1%.

• Journal of Life Science
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• v.12 no.1
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• pp.49-54
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• 2002

Development of a rapid method possessing the requisite sensitivity and specificity for virus monitoring is necessary for protection of the shellfish-consuming public. Oysters tissue usually contains virus particles in relatively small concentrations along with various other substances that can interfere with detection steps. Therefore, the critical point concerning the detection of viruses in shellfish tissues resides in the processing of samples. The current study demonstrated the possibility of purifying small amounts of virus particles at the interface of a 10/50% sucrose gradient after a single round of sucrose gradient ultracentrifugation. We could detect HAV and poliovirus simultaneously from oyster tissues by using two different sets of primer. Furthermore, the method showed a high level of virus recovery rate (>95%) as determined by plaque assays of the final samples. Taken the advantages of the simple and sensitive methods, it was possible to detect 2 pfu of HAV in 5 g of oyster digestive tissues within 24h.

• Fisheries and Aquatic Sciences
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• v.25 no.5
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• pp.287-297
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• 2022

The objective of this study was to evaluate the probability of norovirus foodborne illness by raw oyster consumption. One hundred fifty-six oyster samples were collected to examine the norovirus prevalence. The oyster samples were inoculated with murine norovirus and stored at 4℃-25℃. A plaque assay determined norovirus titers. The norovirus titers were fitted with the Baranyi model to calculate shoulder period (h) and death rate (Log PFU/g/h). These kinetic parameters were fitted to a polynomial model as a function of temperature. Distribution temperature and time were surveyed, and consumption data were surveyed. A dose-response model was also searched through literature. The simulation model was prepared with these data in @RISK to estimate the probability of norovirus foodborne. One sample of 156 samples was norovirus positive. Thus, the initial contamination level was estimated by the Beta distribution (2, 156), and the level was -5.3 Log PFU/g. The developed predictive models showed that the norovirus titers decreased in oysters under the storage conditions simulated with the Uniform distribution (0.325, 1.643) for time and the Pert distribution (10, 18, 25) for temperature. Consumption ratio of raw oyster was 0.98%, and average consumption amount was 1.82 g, calculated by the Pert distribution [Pert {1.8200, 1.8200, 335.30, Truncate (0, 236.8)}]. ₁F₁ hypergeometric dose-response model [1 - (1 + 2.55 × 10^-3 × dose)^-0.086] was appropriate to evaluate dose-response. The simulation showed that the probability of norovirus foodborne illness by raw oyster consumption was 5.90 × 10^-10 per person per day. The annual socioeconomic cost of consuming raw oysters contaminated with norovirus was not very high.

• Korean Journal of Microbiology
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• v.17 no.3
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• pp.97-130
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• 1979

Many industrial processes those employ bacteria are subjected to phage infestations. In L-glutamic acid fermentions using acetic acid, the phage infestations of the organisms have been recently recognized. In efforts to elucidate the sources of phage contamination involved in the abnormal fermentation, a series of study was conducted to isolate the phages both from the contents of abnormally fermented tanks and the soil or sewage samples from the surroundings of a fermentation factory, to define major charateristics of the phage isolates, and finally to determine the correlation between the phage isolates and temperate phages originating from the miscellaneous bacterial species isolated from the soil or sewage samples. The results are summarized as follows; 1) All phages were isolated from the irregular fermentation tanks and soil or sewage samples, and they were designated as phage PR-1, PR-2, PR-3, PR-4, PR-5, PR-6, and PR-7, in the order of isolation. These PR-series phages were proved to be highly specific for the variant strains of Br. lactofermentum only, namely, phage PR-1 and PR-2 for Br. lactofermentum No. 468-5 and phage PR-3~PR-7 for Br. lactofemrentum No. 2256. By cross-neutralization test, the 7 phagescould be subdivided into 3 groups, i. e., phage PR-I and PR-2 the first, phage PR-3, PR-4, PR-5, PR-6 the second, and the phage PR-7 the third. 2) The 7 phages were virulent under the experimental conditions. They produced plaques with clear and relatively sharp margins without distinct halo. The mean sizes of plaques were 1.5mm in diameter for phage PR-1 and PR-2, and 1. Omm for phages PR-3~PR-7. Double layer technique modified by Hongo and described by Adams, was applied to assay of the PR-series phages. The factors influencing the plaques were as follows;young age cells of host bacteria cultured for 3-6 hours represented the largest number and size, optimum was pH 7.0, incubation temperature was $30^{\circ}C$, and agar concentration and amount of overlayer medium were 0.6% and 0.2ml, respectively. 3) PR-series phages were stable in 0.05M tris buffer and 0.1M ammonium acetate buffer solution. The addition of $5{\times}10^{-3}M$ magnesium ion effectively increased the stability. Thermostability experiments indicated that PR-series phages were stable at the teinperture between $50^{\circ}{\sim}55^{\circ}C$ in nutrient medium, $45^{\circ}{\sim}50^{\circ}C$ in buffer solution. However, the phages mere completely inactivated at 603C and 65$^{\circ}$C within 10 minutes. The phages were stable at the range of pH6~9 in nutrient medium and of pH 8-9 in buffer solution, respectively. Exposure of the phages to UV for 25, 60 and 100 seconds resulted in the complete loss of infectivily, respectively. 4) Electron microscopy showed that PR-series phage particles exhibited rather similar morphology, differing in the size All of PR-series phages had a multilateral head and had a simple long tiil about three to five times long as compared with head. By the size, phage PR-1 and PR-2, PR-3, PR-4, PR-5, and PR-6 and PR-7 were classified into same groups, respectively. The head and tail size of phage PR-1, PR-5, PR-5(T) and PR-7 were 85nm, 74nm and 235nm and 350mm, and 72nm and 210nm, respectively. 5) Nucleic acids of PR-series phages were double stranded DNA. The G+C contents of phage PR-1, PR-5 and PR-7 were 56.1, 52.9 and 53.7, respectively. The values of G+C contents derived from the $T_m$ were in agreement with the chemically determined values. 6) PR-series phages effectively adsorbed on their host bacteria at the rate of more than 90% during 5 min. K value for phage PR-1, PR-5 and PR-7 were calculated to be $6{\times}10^9 ml$ per minute, respectiveky. The pH of the medium did effect adsorption rate, but both temperature and age of host cells did not. Generally, optimum adsorption condition of phages seemed to be almost same as optimum growth conditions of host bacteria. 7) In one-step growth experiments, the latent periods at $30^{\circ}C$ for PR-1, and PR-7 were about 70, 50 and 55 min, respectively. The corresponding average burst size was 200, 70 and 90, respectively. Lpsis period according to the multiplicity of infection and a phage series. In case of m. o. i. 100, strain No. 2256 (PR-5) and No. 468-5(PR-1) failed to grow and turbidity decreased after 50 and 70min, respectively. 8) In the lysate of a plaque purified phage PR-5 infected bacteria, there observed 2 types ofphage particles, i. e., phage PR-5 and PR-5 (T) of similar morphology but differing at the length of phage tail, and phage tail like particles. The phage taillike particles could be divided into 4 types by the length. Induction experiments of Br. lactofermentum with UV irradiation, mitomycin C or bacitracin treatment produced neither phage PR-5 (T) or phage tail-like particles. 9) No lysis occured when the growth of 7 strains of miscellaneous bacteria, isolated from soil and sewage samples, were inoculated with either phage PR-5 (T) or phage tail-like particles the inoculation of phage PR-5 pellet resulted in the growth inhibition of the orgainsms in the spot test. The lysates obtained from 3 miscellaneous soil derived bacteria following mitomycin C treatment the growth of Br. lactofermentum, but did not lyze the bacterium.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.554-562
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• 2003

Xylitol has been used as sugar substitute to prevent dental caries. It is not fermented by most dental plaque bacteria and interferes with the growth of mutans streptococci. Therefore the production of acidic metabolites and the growth of mutans streptococci are inhibited. S. mutans strains which are inhibited to grow under the presence of xylitol are referred as xylitol-sensitive ($X^S$) strains. However, experimental and clinical studies have shown that there were mutated groups of S. mutans strains that are not affected by xylitol. They are referred as xylitol-resistant($X^R$) strains. The aim of the present study was to investigate that emergence of $X^R$ strain would effect on the anticariogenecity of xylitol by comparing the growth rate, the extracellular pH, hydroxyapatite adhesion and the agglutination of the $X^R/X^S$ strains. Overall we came out with following results : 1. No difference in the growth rate and the extracellular pH was found between the $X^S$ strain and the $X^R$ strain. 2. No difference in adhesion to hydroxyapatite surface was found between the $X^R$ strain and the $X^S$ strain (p>0.05) and adhesion of the $X^S$ strain was greater than that of $X^R$ strain in the sucrose-dependent adhesion to hydroxyapatite (p<0.05). 3. The $X^R$ strain was agglutinated in the lower concentration of saliva than that of $X^S$ strains.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.134-141
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• 2019

Purpose: The purpose of this study was to compare the clinical outcomes of lithium disilicate ceramic pressed zirconia prostheses and monolithic zirconia prostheses and to investigate the complications after two years of follow-up in posterior edentulous site. Materials and methods: A total 17 patients (male: 12, female: 5) were treated with 60 posterior fixed implant-supported prostheses (LP. lithium disilicate ceramic pressed zirconia prostheses: n = 30, MZ. monolithic zirconia prostheses: n = 30). After 24-month, clinical examination of Implant survival rate, marginal bone resorption, probing depth, plaque index, bleeding index, calculus and complications were evaluated. Results: There were no failed implants and all implants were normal in function without mobility. Marginal bone resorption was lower in LP group than MZ group at 12-month (P < .05), and 12-month probing depth and calculus deposit in LP group were significantly higher than MZ group (P < .05). Most common complications in MZ were marginal bone resorptions more than 1.5.mm and 2 chipping occurred in LP group. Conclusion: Within the limitations of the present study, lithium disilicate ceramic pressed zirconia is considered as a predictable treatment option as much as monolithic zirconia in posterior fixed implant-supported prostheses.