• 한국임상수의학회지
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• 제14권2호
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• pp.215-222
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• 1997

Enrofloxacin-colistin combination, widely used in Gram negative infections in veterinary sector, was investigated in terms of MIC and initial killing rate using E coli k 88ab, Salmonella typhimurium, Pasteurella multocida type A, Bordetella bronchiseptica and Staphylococcus aureus as test organisms. On the basis of MICs of enrofloxacin-colistin combination against the above bacteria, killing rates of the combination of enrofloxacin and colistin at the ratio of 5:0, 4:1, 3:2, 1:1, 2:3, 1:4 and 0:5, indicated high and rapid antibacterial acitivities against all but Staphylococcus aureus R-209, with the number of bacteria reducing to less than one percent within two hours. At the MIC of enrofloxacin or colistin, both antibacterials showed the highest killing rates during 2-4 hours against Gram negatives such as E coli K88ab,Pasteurella multocida type A and Bodetella bronchiseptica but allowed the regrowth of the same pathogens thereafter. On the while, the combination of two antibacterials at a fourth MIC resulted in high killing rate without bacterial regrowth during 24 hours, suggesting the synergistic antivacterial effects. The combination, however, did not show favourable activity against Gram negatime S typhimurium and Gram positive S aureus ergistic antibacterial activity against Gram negatime pathogens but also colistin showed LPS-neutraization, we could suggest the combination should provide clinically positive therapeutic armarium in Gram negative infections.

• 한국미생물·생명공학회지
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• 제37권1호
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• pp.80-84
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• 2009

The in vitro antibacterial activities of anti-acne agents prepared from the extracts of natural sources were investigated against several bacteria including antibiotic-susceptible and -resistant Propionibacterium acnes. SD-1 and SD-2 were prepared with different formulations and they showed strong antibacterial activities. The anti-acne agents completely inhibited the growth of the tested strains at the concentration of 0.5%. There was no difference in antibacterial activity between antibiotic-susceptible and -resistant P. acnes. The inhibitory activities of two agents showed time-dependent manner. In S. aureus, time-kill curve demonstrated 2.8- and 3.4-$log_{10}$-unit killing after 8 h with SD-1 and SD-2, respectively. In P. acnes, time-killing curve demonstrated 5.1- and 6.1-$log_{10}$-unit killing after 24 h with SD-1 and SD-2, respectively. SD-2 showed stronger antimicrobial activity than SD-1. From these results, we expect that SD-1 and SD-2 have strong antibacterial activities and have advantages for treating acne.

• 약학회지
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• 제39권4호
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• pp.351-359
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• 1995

The in vitro and in vivo antibacterial activities of DWQ-217 (1-cyclopropyl-6-fluoro-8-chloro-7-(3-amino-4-methylthiomethylpyrrolidinyl )-1,4-dihydro-4-oxo-quinoline-3-carboxylic acid) were compared with those of ciprofloxacin (CPFX) and vancomycin(VCM). DWQ-217 was superior to those of CPFX and VCM against gram positive bacteria. DWQ-217 showed excellent activity against MRSA (MIC of methicillin; $\geq$12.5 $\mu\textrm{g}$/ml), MIC$_{90}$=0.013. DWQ-217 possessed strong bactericidal action against gram positive and gram negative strains by MIC/MBC test and killing curve. DWQ-217 and CPFX were administered orally and subcutaneously to mice infected systematically with S. aureus and S. pyogenes, DWQ-217 was $\geq$5-16 fold(p.o.) and $\geq$3-5 fold(s.c.) more active than CPFX.

• 대한수학회지
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• 제54권4호
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• pp.1331-1343
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• 2017

A curve ${\gamma}$ immersed in the three-dimensional sphere ${\mathbb{S}}^3$ is said to be a slant helix if there exists a Killing vector field V(s) with constant length along ${\gamma}$ and such that the angle between V and the principal normal is constant along ${\gamma}$. In this paper we characterize slant helices in ${\mathbb{S}}^3$ by means of a differential equation in the curvature ${\kappa}$ and the torsion ${\tau}$ of the curve. We define a helix surface in ${\mathbb{S}}^3$ and give a method to construct any helix surface. This method is based on the Kitagawa representation of flat surfaces in ${\mathbb{S}}^3$. Finally, we obtain a geometric approach to the problem of solving natural equations for slant helices in the three-dimensional sphere. We prove that the slant helices in ${\mathbb{S}}^3$ are exactly the geodesics of helix surfaces.

• 대한약침학회지
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• 제19권1호
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• pp.45-50
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• 2016

Objectives: The purpose of this study was to investigate the antifungal effect of bee venom (BV) and sweet bee venom (SBV) against Candida albicans (C. albicans) clinical isolates. Methods: In this study, BV and SBV were examined for antifungal activities against the Korean Collection for Type Cultures (KCTC) strain and 10 clinical isolates of C. albicans. The disk diffusion method was used to measure the antifungal activity and minimum inhibitory concentration (MIC) assays were performed by using a broth microdilution method. Also, a killing curve assay was conducted to investigate the kinetics of the anti-fungal action. Results: BV and SBV showed antifungal activity against 10 clinical isolates of C. albicans that were cultured from blood and the vagina by using disk diffusion method. The MIC values obtained for clinical isolates by using the broth microdilution method varied from $62.5{\mu}g/mL$ to $125{\mu}g/mL$ for BV and from $15.63{\mu}g/mL$ to $62.5{\mu}g/mL$ for SBV. In the killing-curve assay, SBV behaved as amphotericin B, which was used as positive control, did. The antifungal efficacy of SBV was much higher than that of BV. Conclusion: BV and SBV showed antifungal activity against C. albicans clinical strains that were isolated from blood and the vagina. Especially, SBV might be a candidate for a new antifungal agent against C. albicans clinical isolates.

• 대한임상검사과학회지
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• 제38권3호
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• pp.166-172
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• 2006

Metallo-${\beta}$-lactamase (MBL) can hydrolyze all ${\beta}$-lactams except monobactams and frequently coexists with various antibiotic resistance genes such as aminoglycoside resistance, sulfonamide resistance gene, etc. Therefore, the effective antibiotics against infections by these bacteria are markedly limited or can't even be found. We tried to search in-vitro antimicrobial combinations with synergistic effects for a VIM-2 type MBL producing Pseudomonas aeruginosa, isolated from clinical specimen. On the selection of antibiotic combinations with synergistic effects, we performed a one disk synergy test, modified Pestel's method, in agar without aztreonam (AZT). The bacteriostatic synergistic effects of this tests were scored as $S_1$ (by susceptibility pattern in agar without antibiotics), $S_2$ (by the change of susceptibility in agar with or without antibiotics) and $S_3$ ($S_1$ + $S_2$) and was classified into weak (1 point), moderate (2 points) and strong (3 points) by $S_3$ score. Subsequently, we carried out the time-killing curve for the antibiotic combinations with the strong synergistic bacteriostatic effect. One VIM-2 type MBL producing P. aeruginosa confirmed by the PCR showed all resistance against all ${\beta}$-lactams except AZT, aminoglycoside and ciprofloxacin. In the one disk synergy test, this isolate showed a strong bacteriostatic synergistic effect for the antibiotic combination of AZT and piperacillin-tazobactam (PIP-TZP) or AZT and amikacin (AN). On the time-killing curve after six hours of incubation, the colony forming units (CFUs/mL) of this bacteria in the medium broth with both combination antibiotics were decreased to 1/18.7, 1/17.1 of the least CFUs of each single antibiotics. The triple antibiotic combination therapy including AZT, PIP-TZP and AN was shown to be significantly synergistic after 8 hrs of exposure. In a VIM-2 MBL producing P. aeruginosa with susceptibility for AZT, the triple antibiotic combination therapy including AZT, PIP-TZP and AN may be considered as an alternative antibiotics modality against the infection by some MBL type. But the antimicrobial combination therapy for many more MBL producing isolates is essential to know as soon as possible for the selection of effective treatment against the infection by this bacteria.

• 약학회지
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• 제47권6호
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• pp.365-368
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• 2003

The bactericidal activities of DW286, a new fluoroquinolone were investigated by comparing the minimal bactericidal concentrations (MBCs) and the time-kill curve of it against some Gram-positive and Gram-negative bacterial strains. The MBCs of DW286 for the strains tested were either equal to or two-fold higher than the MICs, as were observed for the other fluoroquinolones. And DW286 exhibited rapid killing curves against the strains. Accordingly, it could be said that DW286 has bactericidal activity comparable to other fluoroquinolones.

• 호남수학학술지
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• 제41권1호
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• pp.175-183
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• 2019

In this paper, it is investigated Lorentz force equations for $N_1$ and $N_2$-magnetic curves in 3-Dimensional Euclidean space. We give the Lorentz force in the Bishop frame in ${\mathbb{E}}^3$. Then, we obtain a new characterization for a magnetic field V. Also, we also give examples for each curve.

• 대한한방부인과학회지
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• 제25권3호
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• pp.27-39
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• 2012

Objectives: Recently Ciprofloxacin, used in the treatment of mastitis, showed many serious side effects. The object of this study was to recognize whether TNS and KWT can be used in the treatment of mastitis by observing the in vitro antibacterial effects of TNS and KWT aqueous herbal extracts against S. aureus. Methods: Antibacterial activities of TNS and KWT aqueous extracts against S. aureus ATCC 25923 were detected using standard agar microdilution methods. In addition, the effects on the bacterial growth curve were monitored at MIC and $MIC{\times}2$ levels. The effects on the intracellular killing and bacterial invasion of individual test materials were also observed using Raw 264.6 and MCF-7. The results were compared with Ciprofloxacin, a second generation of quinolone antibiotics in the present study. Results: MIC of aqueous extracts of TNS and KWT against S. aureus were detected as ($0.313{\pm}0.107$) and ($0.137{\pm}0.053$) mg/ml, respectively. MIC of Ciprofloxacin was detected as ($0.469{\pm}0.297$) ${\mu}g/ml$ at same conditions. In addition, TNS, KWT aqueous herbal extracts and Ciprofloxacin were also showed marked dosage-dependent inhibition of bacterial growth, and dramatical inhibitions on the both intracellular killing assays and bacterial invasion using Raw 264.6 and MCF-7 cells were detected. Conclusions: The results obtained in this study suggest that TNS and KWT aqueous herbal extracts showed antibacterial effects against S. aureus, and they also showed dosage-dependent inhibitory effects on the bacterial growth. And they showed the significant intracellular killing and bacterial invasion effects. It means, KWT and TNS may show more potent anti-infectious effects against S. aureus in vivo.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권2호
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• pp.95-99
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• 2001

Giardia lamblia is a parasitic protozoa which is transmitted in the form of a cyst through untreated water and also treated drinking water. Since its presence in water has led to frequent outbreaks of giardiasis and death in many countries, the removal and disinfection of this protozoan cyst from the water supply are of great concern for public health. This study examined the disinfection characteristics of G. lamblia cysts isolated from a Korean patient with giardiasis. When using sodium hypochlorite including 5 or 10 ppm chlorine, the killing rate was initially rapid, however, the disinfection slowed down and a 3log reduction could not be achieved even after 2h. The disinfection effectiveness was also reduced at a lower temperature, thereby implying that the risk o a giardiasis outbreak will be higher in the winter season. A CT (concentration$.$time) curve was constructed based on the results with sodium hypochlorite for use in designing and predicting disinfection performance. The organic chlorination disinfectant SDIS (sodium dichloroisocyanurate) produced a lower pH and a much higher residual effect than sodium hypochlorite. The disinfection of cysts by SDIC continued steadily throughout 2h of contact, although the initial killing rate was lower than that with sodium hypochlorite.