• Journal of Periodontal and Implant Science
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• v.39 no.3
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• pp.303-310
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• 2009

Purpose: The aerosol generated by ultrasonic scaler can contain bacteria or virus which can penetrate into body through respiratory systems of dentists, dental hygienist or patients. The aim of this study is to evaluate the effect of chlorhexidine digluconate as preoperative mouthrinse or lavage for ultrasonic scaler on the reduction of viable organisms in aerosol produced during periodontal treatment using ultrasonic scaler. Methods: 30 patients with moderate chronic periodontitis were included and divided into 3 groups: Control (no preoperative mouthrinse and tap water as lavage), CHG (preoperative mouthrinse with 0.1% chlorhexidine digluconate and tap water as lavage), CHL (no preoperative mouthrinse and 0.1% chlorhexidine digluconate as lavage). Each patient received scaling or subgingival curettage for 30 min. In CHG group, mouthrinse with chlorhexidine digluconate was performed for 1 min. before treatment. Before, during and after scaling or subgingival curettage, air sampling was performed for 7 min. each (1000 L/7 min.) with trypticase-soy agar plate. Agar plates were incubated in $37^{\circ}C$ aerobically. The numbers of colony-forming units (CFU) were counted and compared. Results: The numbers of CFUs of the samples obtained during treatment were $97{\pm}14.0$ in control, $73.1{\pm}14.9$ in CHG group and $44.5{\pm}9.0$ in CHL group. The difference among the 3 groups was determined to be statistically significant (one-way ANOVA with Bonferroni's correction, p-value: 0.0003). In contrast, the numbers of CFU of samples obtained before and after treatment were not significantly different among the groups. Conclusions: Chlorhexidine digluconate used as preoperative mouthrinse or lavage for ultrasonic scaler can reduce the microorganisms in aerosol produced during periodontal treatment using ultrasonic scaler. Less number of microorganisms were detected when chlorhexidine was used as lavage for ultrasonic scaler.

• Microbiology and Biotechnology Letters
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• v.36 no.3
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• pp.173-181
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• 2008

Bovine blood, cell, tissue, and organ are used as raw materials for manufacturing biologics such as biopharmaceuticals, tissue-engineered products, and cell therapy. Manufacturing processes for the biologics have the risk of viral contamination. Therefore viral validation is essential in ensuring the safety of the products. Bovine parvovirus (BPV) is one of the common bovine pathogens and has widely been known as a possible contaminant of biologics. In order to establish the validation system for the BPV safety of biologics, a real-time PCR method was developed for quantitative detection of BPV contamination in raw materials, manufacturing processes, and final products. Specific primers for amplification of BPV DNA were selected, and BPV DNA was quantified by use of SYBR Green 1. The sensitivity of the assay was calculated to be $1.3{\times}10^{-1}\;TCID_{50}/mL$. The real-time PCR method was validated to be reproducible and very specific to BPV. The established real-time PCR assay was successfully applied to the validation of Chinese hamster ovary (CHO) cell artificially infected with BPV. BPV DNA could be quantified in CHO cell as well as culture supernatant. Also the real-time PCR assay could detect $1.3{\times}10^0\;TCID_{50}/mL$ of BPV artificially contaminated in bovine collagen. The overall results indicated that this rapid, specific, sensitive, and robust assay can be reliably used for quantitative detection of BPV contamination during manufacture of biologics.

• Reproductive and Developmental Biology
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• v.29 no.1
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• pp.57-62
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• 2005

One of the critical problems to be solved in transgenic animal production is uncontrollable constitutive expression of foreign genes, which usually results in serious physiological disturbances in the transgenic animal. To circumvent this problem, we constructed and tested two retrovirus vectors designed to express the GFP(green fluorescent protein) gene under the control of the tetracycline-inducible promoters. To maximize the GFP gene expression at turn-on state, WPRE(woodchuck hepatitis virus posttranscriptional regulatory element) sequence was introduced into the retrovirus vectors at downstream region of either the GFP gene or the sequence encoding rtTA(reverse tetracycline-controlled transactivator). Transformed cells were cultured in the medium supplemented with or without doxycycline(tetracycline derivative) for 48 hours, and induction efficiency was measured by comparing the GFP gene expression level using fluorometry and western blotting. Higher GFP expression was observed from the vector carrying the WPRE sequence at 3' side of the GFP gene, while tighter expression control(up to 20 fold) was obtained from the vector in which the WPRE sequence was placed at 3' side of rtTA sequence. The resulting tetracycline inducible vector system may be used in transgenic animal production and gene therapy.

• Korean journal of applied entomology
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• v.22 no.2 s.55
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• pp.52-66
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• 1983

The brown planthopper, N. lugens (Stal), has become a serious pest of rice in tropical Asia during the last decade. At high pest density, its feeding damage causes 'hopperburn' or complete wilting and drying of the rice plant. It also transmits grassy and ragged stunt virus diseases. The estimated losses caused by the pest in tropical Asia exceed $US\$300$ millions. While cultivation of resistant rice varieties has proved to be highly effective against the pest, their long-term stability is threatened because of the evolution of prolific biotypes which can destroy these varieties. At present, identification of biotypes is based principally on the differential reactions of host rice varieties to the pest and on host-mediated behavioral and physiological responses of the pest. Recent findings of morphological differences in adult rostrum, legs, and antennae, body parts that possess receptors for host plant location and discrimination, and cytological differences in N. lugens populations maintained as stock cultures strongly complement other biotype studies. So far, three N. lugens biotypes have been identified in the Philippines. Biotype I can survive on and damage varieties that do not carry and genes for resistance, while Biotype 2 survives on resistant varieties carrying Bph 1 gene and Biotype 3 on varieties carrying gene bph 2. However, none of these biotypes can survive on varieties with genes Bph 3 or bph 4. Several varieties which are resistant in the Philippines are susceptible in India and Sri Lanka as the South Asian biotypes of N. lugens are more virulent than Southeast Asian biotypes. To monitor the pest biotypes in different geographical regions and to identify new sources of resistance, an International Brown Planthopper Nursery has been established in many cooperating countries. The evolution of biotypes is an exceedingly complex process which is governed by the interactions of genetic and biological factors of the pest populations and the genetic makeup of the cultivated varieties. While the strategy for sequential release of varieties with major resistance genes has been fairly successful so far, the monegenic resistance of these varieties makes them vulnerable to the development of the pest biotypes. Therefore, present breeding endeavors envisage utilizing both major and minor resistance genes for effective control of the pest.

• IMMUNE NETWORK
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• v.9 no.1
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• pp.20-26
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• 2009

We previously reported that $IFN-{\gamma}$ producing T cell responses induced by the combined therapy of DNA vaccine and lamivudine for one year are important for the induction of sustained virological response (SVR). However, $IFN-{\gamma}$ production is not sufficient to predict sustained viremia control in chronic hepatitis B (CHB) carriers treated. Methods: Twelve CHB carriers were intramuscularly immunized 12 times at a 4-week interval with 8mg of HBV DNA vaccine during the standard lamivudine treatment (100mg/daily/1 year). The level of cytokines during and after the combined therapy in plasma of all 12 CHB carriers treated was determined by each ELISA kit. Six out of 12 CHB carriers revisited the clinic, and their HBV DNA levels were examined. Results: The combined therapy increased plasma IL-12 and IL-12/p40 ratio during the treatment (baseline vs. peak level: $41.8{\pm}8.3$ vs. $163.1{\pm}29.2\;pg/ml$; p<0.01 and $0.96{\pm}0.25$ vs. $3.58{\pm}0.86$; p<0.01, respectively), and the peak level of plasma IL-12 and IL-12/p40 ratio was evoked at 6 to 10 months during the combined therapy. In particular, CHB carriers with SVR had two and three-fold higher level of the peak plasma IL-12 and plasma IL-12/p40 ratio than non-virological responders (NVRs), respectively ($218.0{\pm}41.4$ vs. $108.1{\pm}28.6\;pg/ml$; p=0.09 and $5.35{\pm}1.38$ vs. $1.80{\pm}0.29$; p<0.05, respectively), while p40 level was consistent during the combined therapy. In addition, there was no significant temporal correlation between the peak IL-12/p40 ratio and the elevation of serum alanine amino-transferase (ALT) in this study, contrast to $IFN-{\alpha}$ therapy which induced peak IL-12 level following ALT flares. Conclusion: Our results indicate that the combined therapy induces the increase of plasma IL-12 and IL-12/p40 ratio, which are associated with long-term SVR in CHB carriers.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.2
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• pp.129-134
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• 2001

Since NNK is one of the most abundant tobacco-specific alkaloids and a strong carcinogenic nitrosamine, it has been used for evaluating a potential of carcinogenicity in the animal models. The present study has attempted to examine the potential of carcinogenicity of NNK in human epithelial cells, from which the cell type the most of cancers including oral cancer and nasal cavity cancer are originated. The cellular model used for the study is a human keratinocyte cell system immortalized by Ad12-SV40 hybrid virus. The cellular system has successfully been used for the carcinogenicity studies because of its limitless life span, epithelial morphology and nontumorigenicity. When cells were treated with a variety of NNK concentrations, levels of saturation density and soft agar colony formation were increased in a dose-dependent fashion. Colonies of large cell aggregates were above 5 at the higher doses. The results indicate that exposure of human cells with NNK induced loss of contact inhibition and increases of anchorage independence and cellular adhesion, which are typical characteristics of the neoplatically transformed cells. When cells were exposed with 100uM NNK for 2hr, mRNA levels of IL-1 and PAI-2 were increased in a dose-dependent manner, but expression of TGF- 1 was not affected. While expression of growth regulatory factors were altered with a short-term exposure, there was no alteration of these factors in the NNK-transformed cells. However, mRNA levels of fibronectin were increased both in the short-term treatment and in the transformation. The results suggest that altered expression of extracellular matrix such as fibronectin following short-term exposure might be fixed in the genome and these altered properties be continuously transfered throughout the cell division. Western blot analysis showed a translocation of PKC- from cytosolic fraction to the particulate fraction, indicating a possible role of NNK in the signal transduction pathway. The present study provided an evidence that NNK in the smoking may be associated with epithelial origin cancer such as oral and nasal cavity cancers. In addition, this study suggested that altered expression of extracellular matrix and PKC may play an important role in the carcinogenic mechanism of NNK.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.1
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• pp.29-36
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• 2017

Objectives: Acquired immunodeficiency syndrome (AIDS) is a disease of the human immune system caused by the human immunodeficiency virus (HIV). People with AIDS are much more vulnerable to infections, including opportunistic infections and tumors, than people with a healthy immune system. The objective of this study was to correlate oral lesions associated with HIV/AIDS and immunosuppression levels by measuring clusters of differentiation 4 (CD4) cell counts among patients living in the middle western regions of Ghana. Materials and Methods: A total of 120 patients who visited the HIV clinic at the Komfo Anokye Teaching Hospital and the Regional Hospital Sunyani of Ghana were consecutively enrolled in this prospective and cross-sectional study. Referred patients' baseline CD4 counts were obtained from medical records and each patient received an initial physician assessment. Intraoral diagnoses were based on the classification and diagnostic criteria of the EEC Clearinghouse, 1993. After the initial assessment, extra- and intraoral tissues from each enrolled patient were examined. Data analyses were carried out using simple proportions, frequencies and chi-square tests of significance. Results: Our study included 120 patients, and was comprised of 42 (35.0%) males and 78 (65.0%) females, ranging in age from 21 to 67 years with sex-specific mean ages of 39.31 years (males) and 39.28 years (females). Patient CD4 count values ranged from 3 to 985 cells/mL with a mean baseline CD4 count of 291.29 cells/mL for males and 325.92 cells/mL for females. The mean baseline CD4 count for the entire sample was 313.80 cells/mL. Of the 120 patients we examined, 99 (82.5%) were observed to have at least one HIV-associated intraoral lesion while 21 (17.5%) had no intraoral lesions. Oral candidiasis, periodontitis, melanotic hyperpigmentation, gingivitis and xerostomia were the most common oral lesions. Conclusion: From a total of nine oral lesions, six lesions that included oral candidiasis, periodontitis, melanotic hyperpigmentation, gingivitis, xerostomia and oral hairy leukoplakia were significantly correlated with declining CD4 counts.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.96-101
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• 2009

Regional odontodysplasia(ROD) is relatively rare localized developmental anomaly of tooth formation in which hard tissue is affected. The maxilla is typically affected than the mandible, and especially the maxillary left quadrant is the most commonly involved. Females are affected twice as often as males, and there is no association with race. Its etiology remains undetermined, but local circulatory disorders, somatic mutations, virus infections, local trauma, hyperpyrexia, irradiation, metabolic disturbances, and hereditary transmission are considered as possible etiologic factors. The affected teeth are likely to be small, hypoplastic, brown, and grooved. Eruption failure or delay is frequently seen as well as abscess or fistulae formation in absence of caries. Radiographically, there is a lack of contrast between the enamel and dentin, both of which are less radiopaque than unaffected counterparts. Moreover, enamel and dentin layers are thin, giving the teeth a “ghost-like appearance”. The pulp chambers and canals are large, the roots seem like to be short and indistinct. A 2-year-3-month old boy came to the department of pediatric dentistry, Yonsei University, with the chief complaint of delayed eruption and abnormal tooth shape on the lower left quadrant. He was diagnosed as regional odontodysplasia based on the clinical and radiographic findings.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.379-385
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• 1983

Forage productivity of Job's tears (Coix lachryma-jobi L.) and adlay (C. lachryma-jobi var. mayuen (ROMAN.) STAPF) and a hybrid corn (Kwangog) and sorghum-sudangrass hybrid (Pioneer 988) was compared in the southern part of Korea where black streaked dwarf virus' (BSDV) is prevalent. Emergence of Job's tears and adlay was more delayed compared to a corn or sorghum-sudangrass hybrid under the drought field conditions. Early growth and regrowth of Job's tears and adlay were less than those of sorghum-sudangrass hybrid. Fresh weight, dry weight, and digestible dry matter of Job's tears and adlay cut once approximately 40 days after flowering were much higher than those of two cuts at every flowering stage. Dry weight of one-cut Job's tears and ad lay harvested 40 days after flowering was similar to the total dry weight of three-cut sorghum-sudangrass hybrid but higher than that of silage corn. Digestible dry matter production was greater in the order of sorghum-sudangrass, corn, one-cut and two-cut Job's tears and adlay. Corn was severely infected with BSDV, but digestible dry matter was relatively high due to its higher in vitro dry matter digestibility. Among the Job's tears and adlay varieties, a variety of Job's tears with globular fruit shape was best for forage production due to its taller plant height, thick stem, wider leaf blades, higher leaf blade/total dry weight ratio, and higher forage yield. However, hulled grain yield of ad lay varieties was higher than that of Job's tears due to a higher hulled/rough grain ratio although they had similar rough grain yields.

• Journal of Life Science
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• v.11 no.1
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• pp.57-64
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• 2001

The cDNA encoding human NeuAc ${\alpha}$2,3Gal$\beta$ 1,3GalNAc GalNac ${\alpha}$2,6-Sialyltransferase (hST6GalNac IV) was isolated by screening of human fetal liver cDNA library with a DNA probe generated from the cDNA sequence of mouse ST6Gal NAc IV (mkST6GalNAc IV). The cDNA sequence included an open reading frame coding for 302 amino acids, and comparative analysis of this cDNA with mST6GalNAc IV showed that each sequence of the predicted coding region contains 88% and 85% identifies in nucleotide and amino acid levels, respecively. The primary structure of this enzyme suggested a putative domain structure, like that in other glycosyltransferases, consisting of a short N-terminal cytoplamic domain, a transmembrane domain and a large C-terminal active domain. This enzyme expressed in COS-7 cells echibited transferase activity toward NeuAc ${\alpha}$2,3Gal$\beta$ 1,3GalNAc, fetuin and GM1b, although the activity toward the later is very low, no significant activity being detected toward Gal${\beta}$ 1,3Gal NAc or asialofetuin, the other glycoprotein substrates tested. The $^{14}$ C-sialylated residue of fetuin sialylated by this enzyem with CMP-[$^{14}$C]NeuAc was sensitive to treatment with ${\alpha}$2,8-specific sialidase of Vibrio cholerae but resistant to treatment with ${\alpha}$2,3-specific sialidase (NaNase I), and ${\alpha}$2,3- and ${\alpha}$2,8-specific sialidase of Newcastle disease virus. These results clearly indicated that the expressed enzyme is a type of GalNAc ${\alpha}$2,6-sialyltransferase like mST6GalNAc IV, which requires sialic acid residues linked to Gal${\beta}$1,3GalNAc-residues for its activity.