• The korean journal of orthodontics
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• v.23 no.3 s.42
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• pp.311-318
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• 1993

This study was done to evaluate the effect of fixed orthodontic patients on the level of oral streptococci, Streptococcus mutans, lactobacilli, yeasts in saliva. 35 patients wearing bands were compared with age-matched 35 non-banded control group by conlony counting method on the specially designed culture medium. The following results were obtained ; 1. The colony forming unit(CFU) of total streptocci per militer of saliva in subjects with or without orthodontic treatment showed no significant statistical difference between them(p>0.05). 2. The colony forming unit(CFU) of total Streptococcus mutans per mililiter of saliva in subjects with orthodontic treatment showed significantly higher than those without orthodontic treatment(p<0.05). 3. The colony forming unit(CFU) of total lactobacilli per mililiter of saliva in sujects with or without orthodontic treatment showed no significant statistical difference between them but higher tendency in those with orthodontic treatment(p=0.052). 4. The colony forming unit(CFU) of total yeasts per mililiter of saliva in subjects with or without orthodontic treatment showed no significant statistical difference between them(p>0.05).

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.775-778
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• 2001

Chemokines are small chemotalic cytokines that have a number of biological functions. Some chemokines regulate the proliferation of hematopoietic stem and progenitor cells(HSPC). Leukotactin-l(Lkn-l) is a CC chemokine and is known to reduce colony forming unit(CFU). The N-terminal truncated Leukotactin-l(rtLkn-l), produced by Pichia pastoris, suppressed CFU from 40 to 60%. The rtLkn-l protected CFU from cytotoxic effect of anticancer drug such as Ara-C, doxorubicin, cyclophosphamide and 5-FU by cell cycle arrest.

• Journal of Korean society of Dental Hygiene
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• v.17 no.1
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• pp.13-25
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• 2017

Objectives: The purpose of this study was to compare colony forming unit (CFU) method and multiplex real-time polymerase chain reaction (MRT-PCR) method for accurate quantitative analysis of bacteria. Methods: We compared the CFU method and the MRT-PCR method, which are still used in Korea, for Prevotella intermedius (P. intermedius), a periodontal disease pathogen selected by MRT-PCR, and Streptococcus mutans (S. mutans), a dental caries causative organism. The subjects of this study were 30 patients who visited the C dental hospital. Results: Total microorganisms in MRT-PCR method were significantly higher in both types of bacteria (p<0.05), since DNA of dead bacteria was also analyzed. This was because the periodontal dise(-) anaerobes, and even dead bacteria contain large amounts of toxic substances called LPS in the extracellular membrane, and fimbriae and pili, which are motility structures, still remain as a strong toxic substance in periodontal tissue. Conclusions: Therefore, in terms of the total amount of bacteria found, the MRT-PCR method will be a useful technique for searching all the bacteria in the oral cavity including live bacteria, as well as sterilization.

• Clinical and Experimental Pediatrics
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• v.48 no.8
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• pp.894-900
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• 2005

Purpose : Because of the unavailability of marrow transplantation, umbilical cord blood (CB) is increasingly being used. We evaluated the potential of ex vivo expansion and clonality in CD34+ cells separated from cord blood source and mobilized peripheral blood (PB) in a serum-free media. Methods : The CD34+ cells, selected from CB and mobilized PB, were expanded with hematopoietic growth factors. They were then cultured for burst-forming units of erythrocytes (BFU-E), colony-forming units of granulocytes and monocytes (CFU-GM) and colony-forming units of megakaryocytes (CFU-Mk) at culture days 0, day 4, day 7, and day 14 with various growth factors. Results : The CB-selected CD34+ cells showed significantly higher total cell expansion than those from the PB at day 7 (2 fold increase than PB). The CB-selected CD34+ cells produced more BFU-E colonies than did the PB on culture at days 7 and at day 14. Also, the CB-selected CD34+ cells produced more CFU-Mk colonies than did the PB on culture at day 4 and at day 7. Conclusion : The ex vivo expansion of the CB cells may be promising in producing total cellular expansion, CFU-Mk and BFU-E compared with PB for 7 to 14 days. The growth factors combination including megakaryocyte growth and development, flt3-ligand and interleukin-3 showed more expansion in the view of total cells and clonal maintenance compared with less combination.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.6
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• pp.728-733
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• 2007

Presence and distribution of bacteria and fungi in inner compartment of PCs(Personal Computers) were investigated. Samples for the analysis were collected from inside of PCs which had been used in various facilities including public computer facilities, laboratories and computer training rooms of a university. Total number of PC examined in this study was 51 each. When the total CFU(colony forming unit) of the inner compartment of the PCs was measured, the bacterial count was found to be dependent on the operation time(total running time) of PCs. When the distribution of bacteria in the inner compartment of PCs was estimated, CPU(Central Processing Unit) cooling fan area showed the highest bacterial concentration(average 605 $CFU/cm^2$). In the case of the fungi, various opportunistic pathogens including Aspergillus sp. and Penicillium sp. were isolated and identified in the inner compartment of PCs. And the average of bacterial number in the dust collected from the PCs was 212 CFU/mg. These results indicated that handling of PC might have a risk of infection by the microorganism.

• Biomolecules & Therapeutics
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• v.8 no.3
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• pp.213-216
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• 2000

In vivo administration of Leucostim, a human recombinant granulocyte colony-stimulating factor (G-CSF), was evaluated for the effects on survival, hematologic recovery, and colony forming unit- spleen (CFU-5) in murine bone marrow transplantation (BMT) model. Sublethally irradiated (9 Gy) mice received bone marrow cells from untreated mice, and then were treated with G-CSF subcutaneously at doses of 2.5,5, or $10\mu\textrm{g}$/kg or vehicle solution (control) for 14 days from one day after BMT. There was no effect of irradiation and BMT on mortality. The repeated subcutaneous injections of Leucostim for 14 days post- BMT significantly facilitated hematologic recovery compared with vehicle control in a dose-dependent manner. Moreover, mice treated with Leucostim had significantly increased numbers of CFU-s colonies on day 10 post-BMT. These results suggest that Leucostim, a new G-CSF, has beneficial effects on hematologic reconstitution after BMT.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.364-366
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• 2004

The purpose of this work was to investigate the effect oftea catechin, epigallocatechin gallate (EGCG) on killing of oral bacteria. The antibacterial activity of 2.5 mg/ml and 5.0 mg/ml EGCG was investigated for target bacteria of which initial cell number was approximately adjusted to $10^{7}ml$. The antibacterial activity of EGCG was proportional to the concentration according to colony-forming unit(CFU) of target bacteria enumerating on selective and complex media. Streptococcus mutans and Streptococcus sobrinus at 5mg/ml EGCG were completely killed within 8 hrs. Lactobacillus plantarum and Lactobacillus acidophilus were also killed within 2 hrs and 4 hrs under the same conditions, respectively. Oral bacteria at 2.5 mg/ml EGCG were completely killed within 10 hr. Colony numvers of S. mitis and S. salivarius treated with 2.5 mg/ml EGCG were decreased on MS solid media and no colony was observed on the media within 12 hrs. In consequence, EGCG would be a natural and effective compound that kill oral bacteria being caused of bad breath, plaque and gingivitis, and for preventing and treating dental caries.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.2
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• pp.120-127
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• 2020

The aim of this study was to evaluate the antimicrobial effect of photodynamic therapy (PDT) using plaque disclosing agent, 10 - 20 mM erythrosine, as a photosensitizer. Multispecies cariogenic biofilms containing Streptococcus mutans, Lactobacillus casei and Candida albicans were formed on hydroxyapatite disc. 20 μM, 10 mM and 20 mM erythrosine were applied as a photosensitizer for 3 minutes, and then light-emitting diode (LED) irradiated for 24 seconds. Colony-forming unit (CFU) were measured and biofilms were observed using confocal laser scanning microscopy (CLSM). CFU were significantly decreased in the PDT groups using 10 - 20 mM erythrosine (10 mM, 20mM) and the results were also confirmed by CLSM. This study confirms the high antimicrobial effect of photodynamic therapy using plaque disclosing agent as a photosensitizer.

• Journal of Korean Foot and Ankle Society
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• v.18 no.3
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• pp.100-107
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• 2014

Purpose: The purpose of this study is to evaluate the efficacy of mesenchymal stem cell (MSC) isolation by the magnetic-activated cell sorting (MACS) method in tendon tissue-derived cells compared to the colony picking method for isolation of MSCs by picking colony-forming cells. Materials and Methods: Human tendon-derived cells were isolated by enzyme digestion using normal tendon tissues from three donors. We used the magnetic kit and well-known MSC markers (CD90 or CD105) to isolate MSCs in tendon-derived cells using MACS. Cloning cylinders were used to isolate colony-forming cells having MSC characteristics in tendon-derived cells. Colony-forming unit-fibroblast (CFU-F) assay was used to evaluate the self-renewal capacity of cells isolated using the colony picking method or MACS. For comparison of differentiation potentials into osteogenic or adipogenic lineage between two groups, alizarin red S and oil red O staining were performed at 14 days after induction of differentiation in vitro. Results: Flow cytometry results showed that early passage tendon-derived cells expressed CD44 in 99.13%, CD90 in 56.51%, and CD105 in 86.19%. In the CFU-F assay, CD90+ or CD105+ cells isolated with MACS showed larger colony formation in size than cells isolated using the colony picking method. We also observed that CD90+ or CD105+ cells were constantly differentiated into both osteogenic and adipogenic lineages in cells from all donors, whereas cells isolated using the colony picking method were heterogeneous in differentiation potentials to the osteogenic and adipogenic lineages. Conclusion: CD90+ or CD105+ cells isolated using MACS showed superior MSC characteristics in the self-renewal and multi-differentiation capacities compared with cells isolated using the colony picking method.

• Journal of Radiation Protection and Research
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• v.33 no.3
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• pp.99-104
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• 2008

According to the increase in the use of radiotherapy to cancer patients, many approaches have been tried to develop new agents for the protection of surrounding normal tissues. However, it is still few applied in the clinic as a radioprotector. We aim to find a representative parameter for radioprotection to easily predict the activity of in vivo experiment from the results of in vitro screening. The polysaccharide extracted from Panax ginseng was used in this study because the immunostimulator has been regarded as one of the radioprotective agent category and was already reported having a promising radioprotective activity through the increase of hematopoietic cells and the production of several cytokines. Mitogenic activity, AK cells activity and nitric oxide production were monitored for the in vitro immunological assay, and endogenous colony-forming unit (e-CFU) was measured as in vivo radioprotective parameter. The immunological activity was increased by the galactose contents of ginseng polysaccharide dependently. The result of this study suggests that mitogenic activity of splenocytes demonstrated a good correlation with in vivo radioprotective effect, and may be used as a representative parameter to screen the candidates for radioprotector.