• Journal of Korean Society of Environmental Engineers
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• v.39 no.11
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• pp.613-625
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• 2017

For two agricultural reservoirs that are rented for fishing spots, benthic nutrient fluxes experiment were performed two times with two sediments from fishing-effective zone and one sediment from fishing-ineffective zone using laboratory core incubation in oxic and anoxic conditions. During benthic nutrient fluxes experiment, the changes in DO, EC, pH, and ORP in the supernatant were not significantly different between fishing-effective zone and fishing-ineffective zone, and were similar to the sediment-hypolimnetic diffused boundary layer in agricultural reservoir. Except for $NO_3{^-}-N$, more benthic nutrient fluxes of $NH_4{^+}-N$, T-P, and $PO{_4}^{3-}-P$ from sediment to hypolimnetic was measured in anoxic than in oxic conditions (p<0.05). As the DO concentration in hypolimnetic decreases, the microorganism-mediated ammonification is promoted, the nitrification is suppressed, and finally the $NH_4{^+}-N$ diffuses out from sediment to hypolimnetic. Also, the diffusion of T-P and $PO{_4}^{3-}-P$ from sediments to hypolimnetic is accelerated through the dissociation of the phosphorus bound to both organic matters and metal hydroxides. The difference in the benthic nutrient diffusive fluxes between fishing-effective zone and fishing-ineffective zone was not statistically significant (p>0.05). Therefore, it was found that fishing activities did not increase the benthic nutrient diffusive fluxes to a statistically significant level. Due to the short fishing activities of 10 years and the rate-limited diffusion of the laboratory core incubation, the contribution of fishing activities on sediment pollution is estimated to be low. No significant correlation was found between the total amount of nutrients in sediment and the benthic nutrient diffusive fluxes in both aerobic and anaerobic conditions. Therefore, nutrients input from various nonpoint sources of watersheds are considered to be a more dominant factor rather than fishing activities in water quality deterioration, and both aeration and water circulation in hypolimnetic were required to suppress the anoxic environment in agricultural reservoirs.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.605-616
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• 2004

Subinhibitory concentrations (sub-MICs) refer to concentrations below minimum inhibitory concentrations (MICs). The antimicrobial agents may be present at relatively high concentration, at least higher than bacterial MIC and thereafter be deserted off a surface and function at sub-MICs, perhaps by interfering with bacterial metabolism. Consequently, the aim of this study was to determine the effects of growth, in the presence of sub-MICs of antimicrobial agents, on the cell surface properties and virulence factors of mutans streptococci and to investigate the efficacy of a chemical approach in vitro. Streptococcus mutans Ingbritt and Streptococcus sobrinus 6715-7 were used. Eight antimicrobial agents (Sanguinaria extract;SG, Chlorhexidine digluconate;CHX, Fluoride;F, Propolis;PP, Hydrogen peroxide;HP, Triclosan;TC, Sodium dodecyl sulfate;SDS Cetylpyridinium chloride; CC) were diluted serially in broth to determine MICs and to compare the growth rate, acid production, hydrophobicity, adhesion activity to saliva coated hydroxyapatite, glucan synthesis and cellular aggregation of experiment groups (in the presence of sub-MICs) with those of control (in the absence of antimicrobial agents). Sub-MICs of antimicrobial agents affected the growth of cells, hydrophobicity, and adhesion of bacteria to saliva coated hydroxyapatite and glucan synthesis. They also resulted in a significant reduction in pH after 12 hours (p<0.05). By cells pretreated with proteinase K, either the aggregation induced by antimicrobial agents was completely inhibited or the aggregation titers were markedly increased. According to the results of the present study, each antimicrobial agent at sub-MICs could affect similar as its known action mechanism and could continually inhibit cariogenic bacteria at such concentrations. Thus, the use of these antimicrobial agents would be one of the effective methods to prevent dental caries.

• Tuberculosis and Respiratory Diseases
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• v.45 no.6
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• pp.1199-1213
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• 1998

Background : The number of immunocompromised hosts has been increasing steadily and a new pulmonary infiltrate in these patients is a potentially lethal condition which needs rapid diagnosis and treatment. In this study we sought to examine the clinical manifestations, radiologic findings, and therapeutic outcomes of pulmonary mycoses presenting as a new pulmonary infiltrate in immunocompromised hosts. Method : All cases presenting as a new pulmonary infiltrate in immunocompromised hosts and confirmed to be pulmonary mycoses by pathologic examination or by positive culture from a sterile site between October of 1996 and April of 1998 were included in the study and their chart and radiologic findings were retrospectively reviewed. Results : In all, 14 cases of pulmonary mycoses from 13 patients(male : female ratio = 8 : 5, median age 47 yr) were found. Twelve cases were diagnosed as aspergillosis while two were diagnosed as mucormycosis. Major risk factors for fungal infections were chemotherapy for hematologic malignancy(10 cases) and organ transplant recipients(4 cases). Three cases were receiving empirical amphotericin B at the time of appearance of new lung infiltrates. Cases in the hematologic malignancy group had more prominent symptoms : fever(9/10), cough(6/10), sputum(5/10), dyspnea(4/10), chest pain(5/10). Patients in the organ transplant group had minimal symptoms(p<0.05). On simple chest films, all of the cases presented as single or multiple nodules(6/14) or consolidations(8/14). High resolution computed tomograph showed peri-lesional ground glass opacities(14/14), pleural effusions(5/14), and cavitary changes(7/14). Definitive diagnostic methods were as follows : 10 cases underwent minithoracotomy, 2 underwent video-assisted thoracoscopic surgery, 1 underwent percutaneous needle aspiration and 1 case was diagnosed by culture of abscess fluid. All cases received treatment with amphotericin B with 1 case each being treated with liposomal amphotericin B and itraconazole due to renal toxicity. Lung lesion improved in 12 of 14 patient but 4 patients died before completing therapy. Conclusion : When a new lung infiltrate develops presenting either as a nodule or consolidation in a neutropenic patient with hematologic malignancy or in a transplant recipient, you should always consider pulmonary mycoses as one of the differential diagnosis. By performing aggressive work up and early treatment, we may improve prognosis of these patients.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.43-46
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• 2007

Purpose : Neonatal bacterial meningitis has been known that its mortality and morbidity is high and its neurologic complications are common. This study was performed to review of the etiology of neonatal bacterial meningitis in Busan, Korea. Methods : We retrospectively analyzed 21 medical records of patients who were diagnosed neonatal bacterial meningitis in four university hospitals in Busan from January 1997 to December 2005. We analyzed age at onset of symptoms, symptoms at admission, causative organisms, and complications. Results : There were 11 male patients and 10 female patients. One premature neonate was included. 7 patients had symptoms at 2-3 weeks after birth and 6 patients at 1-2 weeks after birth. 18 cases had fever, 8 cases had seizure and some had poor feeding, lethargy and irritability. The most common organism causing neonatal bacterial meningitis was Group B streptococcus (GBS). 11 cases were due to GBS, 3 cases due to E. coli, 3 cases were due to Klebsiella pneumoniae, and 2 cases due to Streptococcus pneumoniae. one Listeria monocytogenes and one Enterobacter cloacae were included. 18 patients were alive and 3 patients died. Mental retardation, developmental delay and epilepsy occurred in a living patient. Conclusions : Although this was a retrospective study, we found that Group B streptococcus (GBS) was the most common organism causing neonatal bacterial meningitis and this data is nearly same as others in the world.

• Journal of Chest Surgery
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• v.41 no.2
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• pp.149-159
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• 2008

Background: With increasing coronary bypass and peripheral vascular surgeries, the demand for homologous vascular or synthetic conduits has continued to grow, but wide-spread application has been limited by dismal patency rates. Although cryopreserved allograft valves may provide a suitable alternative, current viability or patency of implanted allograft vascular conduits has been unsatisfactory. Material and Method: We serially analyzed the outcomes of canine femoral artery and saphenous vein allograft implants after storage in either $4^{\circ}C\;or\;-170^{\circ}C$. Result: There were no differences in graft flow rate (patency) (p=0.264), rate of thrombosis (p=0.264), presence of endothelium (p=0.587), or immunohistochemical staining for thrombomodulin (p=0.657) were detected between grafts stored in $4^{\circ}C\;and\;-170^{\circ}C$. Greater flow occurred in the arterial grafts versus the venous grafts (p=0.030), irrespective of the preservation method, with a significantly lower incidence of thrombosis (p=0.030) in arterial allografts. There was a correlation coefficient of -0.654 between thrombosis and positive immunohistochemical staining for thrombomodulin (p=0.006) and a correlation coefficient of 0.520 (p=0.0049) between the endothelial presence and positive immunohistochemical staining for thrombomodulin. The relationship between the presence of endothelium and thrombomodulin expression failed to show any correlation within the first 2 weeks (p=0.306). However, a strong correlation was seen after 1 month (p=0.0008). Conclusion: Tissue storage in either $4^{\circ}C\;or\;-170^{\circ}C$ in 10% DMSO/RPMI-1640 preservation solution preserved grafts equally well. In terms of thrombosis and graft patency, arterial grafts were superior to venous grafts. Considering the poor correlation between thrombomodulin expression and the presence of an endothelium in the implanted graft within the first two weeks, grafts in this period would not be thromboresistant.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.428-434
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• 2009

This study was conducted to evaluate the anti-hypertensive effect of Lactobacillus sp. isolated from Kimchi by examining its effects on renal angiotensin-converting enzyme (ACE) inhibitory activity, lipid components and blood pressure using the spontaneously hypertensive rat (SHR) system. Most Lactobacillus sp. extracts (lysozyme, sonication and ethyl acetate extracts) showed higher capacities for the inhibition of ACE activity than those of cultured media. Particularly, LG 7, 8 and 42 of Lactobacillus sp. showed the strongest inhibitory activity among the Lactobacillus sp. extracts. The concentrations of total cholesterol and triglycerides in the serum were lower in the Lactobacillus sp. administration groups than in the control group, but these differences were not significant. The HDL-cholesterol concentrations of the LG 42 administration groups (IX, X) were significantly higher than that of the control group. At 4 weeks, the systolic blood pressure (SBP) in the LG 42 Lactobacillus sp. ($1{\times}10^9$ cfu/mL) group (XI) was about 27% lower than that of the control group (V). No adverse effects were observed on the liver and there was no difference in the aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values among groups. The results of this study suggest that long term consumption of LG 42 Lactobacillus sp. may be beneficial to the prevention of high blood pressure.

• Journal of Chest Surgery
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• v.36 no.10
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• pp.711-720
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• 2003

Bakground : Complete resection by the surgery has been selected as the treatment of choice in lung cancer patients, but in cases of recurrence after excision or inoperable cases, the importance of anticancer chemotherapy has been emphasized. If one can select a set of the sensitive chemotherapeutic agents before anticancer chemotherapy, it will give more favourable results. Subrenal capsular assay has been recognized as a useful in-vivo chemosensitivity test of thoracic and abdominal tumors and it can be done in a short time for a rapid interpretation of tumor responsiveness to anticancer chemotherapeutic drugs. It has been reported that various kinds of cancer cells can be implantable to the kidney, but so far there is no comparative study of xenogeneic cell implantation on liver, spleen and kidney. The author implanted the human lung cancer cells under the capsule of S.D rat's liver, spleen and kidney respectively and compared the pattern of growth and histology. Material and Method: After incubation of human lung cancer cell line (SW-900 G IV) in RPMI 1640 (Leibovitz L-15 medium) culture media, 3${\times}$3${\times}$3 mm size fibrin clots which contain 108 cancer cells were made. Thereafter the fibrin clots were implanted at subcapsule area of liver, spleen and kidney of S.D. female rat. For immune suppression, cyclosporin-A (80 mg/Kg) was injected subcutaneously daily from post-implantation first day to sixth day. The body weight was measured at pre and post implantation periods. The growth pattern and the size of tumor mass were observed and the pathologic examination and serum tumor marker tests were performed. Result: Body weight increased in both of control and experimental groups. Serum Cyfra 21-1 was not detected. Serum levels of CEA and NSE revealed no significant change. The SCC-Ag increased significantly in implanted group. The growth rate of human lung cancer cells which was implanted on spleen was higher than on liver or kidney. The surface area, thickness, and volume of tumor mass were predominant at spleen. The success rates of implantation were 80% on kidney, 76.7% on spleen and 43.3% on liver. Pathologic examination of implanted tumors showed characteristic findings according to different organs. Tumors that were implanted on kidney grew in a round shape, small and regular pattern. In the spleen, tumors grew well and microscopic neovascularization and tumor thrombi were also found, but the growth pattern was irregular representing frequent daughter mass. Human lung cancer cells that were implanted in the liver, invaded to the liver parenchyme, and had low success rate of implantation. Microscopically, coagulation necrosis and myxoid fibrous lesion were observed. Conclusion: The success rate of implantation was highest in the kidney. And the mass revealed regular growth that could be measured easily. The SCC-Ag was presented earlier than CEA or Cyfra21-1. The Cyfra21-1 was not detected at early time after implantation. The best model for tumor implantation experiment for chemosensitivity test was subrenal capsular analysis than liver and spleen and the useful serum tumor marker in early period of implantation was the SCC-Ag.

• Pediatric Infection and Vaccine
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• v.22 no.2
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• pp.106-112
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• 2015

Purpose: The long-term administration of antibiotics interferes with bacterial culture in the middle ear fluids (MEFs) of young children with otitis media with effusion (OME). The purpose of this study is to determine whether molecular diagnostics can be used for rapid and direct detection of the bacterial pathogen in culture-negative MEFs. Methods: The specificity and sensitivity of both polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) to the lytA gene of Streptococcus pneumoniae were comparatively tested and then applied for pneumococcal detection in the clinical MEFs. Results: The detection limit of the PCR assay was approximately $10^4$ colony forming units (CFU), whereas that of LAMP was less than 10 CFU for the detection of S. pneumoniae. Both PCR and LAMP did not amplify nucleic acid at over $10^6$ CFU of H. influenzae or M. catarrhalis, both of which were irrelevant bacterial species. Of 22 culture-negative MEFs from children with OME, LAMP positivity was found in twelve MEFs (54.5%, 12/22), only three of which were PCR-positive (25%, 3/12). Our results showed that the ability of LAMP to detect pneumococcal DNA is over four times higher than that of PCR (P<0.01). Conclusions: As a high-resolution tool able to detect nucleic acid levels equivalent to <10 CFU of S. pneumoniae in MEFs without any cross-reaction with other pathogens, lytA -specific LAMP may be applied for diagnosing pneumococcus infection in OME as well as evaluating the impact of a pneumococcal conjugate vaccine against OME.

• Clinical and Experimental Pediatrics
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• v.46 no.12
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• pp.1224-1229
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• 2003

Purpose : Bacterial meningitis is a serious disease, especially in the neonatal period, and it carries a significant degree of mortality and morbidity. Group B streptococcus(GBS) is a common cause of neonatal bacterial meningitis. The purpose of this study was to evaluate the clinical manifestations, treatment results and complications of GBS meningitis. Methods : We analyzed 29 cases retrospectively who had been admitted to the pediatric ward or NICU in Asan Medical Center from May 1990 to January 2002. They had proven GBS in culture or latex agglutination test in CSF. Results : The male to female ratio was 1 : 1.9. There were two cases of early onset type and 27 cases of late onset type. All cases had normal birth weight with full term at delivery. The perinatal predisposing factors were premature rupture of membrane(two cases), and maternal colonization(two cases). The most common presenting symptoms were fever and irritability. Associated diseases were GBS sepsis(21 cases). There was relatively high sensitivity to penicillin derivatives. There were abnormal brain CT or MRI findings in 16 cases(64%), such as infarction, encephalomalatic change, effusion, hydrocephalus, hemorrhage and abscess. The intensive care unit admission rate and the incidence of DIC were higher in the group with complications. Two cases were discharged against advice. Conclusion : We recommend early detection and active treatment in Group B streptococcal meningitis to improve the prognosis.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.4
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• pp.325-333
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• 1992

An investigation was carried out to find out the effects of long-term application (14 and 28 years) of rice straw, compost and wheat straw on changes in soil chemical and physical properities, aspests of releasing potential nitrogen and nitrogen uptake by rice and maize from fine textured paddy soils with double cropping system in warm temperate area. The result obtained were summarized as follows : 1. The long-term application of organic matters improved plow layer and soil physical properties : bulk density and solid phase were decreased, while porosity and gaseous phase were decreased. 2. Average increment of total carbon per year was 0.0371% and 0.0407% for rice straw and compost, respectively, from 1 through 14 years ; it was 0.0007% and 0.0014% for the rice straw and compost, respectively, from 15 years through 28 years. The average increment of total notrogen per year was 0.0025% and 0.038% for the rice straw and compost, respectively, from 1 through 14 years ; 0.0014% and 0.0024% for the same treatments from 15 through 28 years. 3. $NH_4-N$ and amide-N were high in the soils with wheat straw application for 28 years ; the amino sugar-N in the soils with compost application for 28 years ; amino acid -N in the soils with rice straw application for 14 and 28 years ; and unidentified-N, in the control. 4. The released amount of available nitrogen with the submerged condition was higher at $30^{\circ}C$ than at $25^{\circ}C$ during the incubation. The amount of released available nitrogen at the field was aproximately same as that of $25^{\circ}C$ incubation. However, the released amounts from the incubation and the field were always lower than those extracted with reagents. 5. The amount of nitrogen uptake by rice and maize was highly correlated with available nitrogen extracted with phosphate buffer(pH 7.0). 6. The ratio of yield increase(milled rice) was 17, 12 and 7%, respectively, by application of rice straw, compost and wheat straw for 28 years, and 11% by application of rice straw for 14 years.