• Safety and Health at Work
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• v.14 no.3
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• pp.287-294
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• 2023

Background: Fruit and vegetable market is an abundant source of bioaerosols. Exposure to organic and inorganic waste and long-term inhalation of bioaerosols during working hours leads to chronic respiratory symptoms. Hence, this study aimed to determine the prevalence of chronic respiratory symptoms and related factors among fruit and vegetable workers compared with the control group in Addis Ababa, Ethiopia. Methods and materials: A comparative cross-sectional study was conducted from 2020 to 2021. Data were entered in EpiData 3.1 and exported to Statistical Package for the Social Sciences (SPSS) version 25. Logistic regressions were computed to depict the data and related factors. The culture method was done to count and compare bacterial and fungal concentrations between fruit and vegetable workers and office workers. Results: In this study, the prevalence of chronic respiratory symptoms (PR = 2.87, 95% confidence interval [CI]: 1.772-4.66) was significantly higher among fruit and vegetable workers (46.7%) than controls (23.4%). Sex (adjusted odds ratio [AOR] = 2.11, 95% CI = 1.12-3.98), educational status (AOR = 1.34, 95% CI = 0.78-2.32), working hours per day (AOR = 3.91, 95% CI = 1.586-9.65), and working department (AOR = 3.20, 95% CI = 0.90-11.40) were associated with chronic respiratory symptoms. Bacterial and fungal concentrations were significantly higher in the air of the vegetable market (276 colony-forming unit) than the air in the workplace of controls (7 colony-forming unit). Conclusion: The fruit and vegetable market workers (greengrocers) had a higher prevalence of chronic respiratory symptoms relative to office workers. Respiratory protective devices should be given to deliver preventive measures.

• Biomolecules & Therapeutics
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• v.8 no.2
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• pp.199-205
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• 2000

On the inter-order protoplast fusants of Lentinus edodes and Ganoderma lucidum was the antitumor activity test performed and the fusant P22 was selected. The hot water extract of the cultured mycelia of P22 were purified by DEAE-cellulose chromatographya and the resulting purified fraction was designated as P22A. It was found to be a proteoglycan whose molecular weight was 47 kDa. When examined for immunopotentiation activity, P22A increased the number of colony forming unit in the bone marrow stem cells to 3-folds. It also potentiated the secretion of nitric oxide in activated macrophages to 2-folds. In humoral immune response, it increased the activities of the alkaline phosphatase in differentiated B cells to 1.6-folds and the number of plaque forming cells to 1.8-folds. In cellular immune response, it restored the depressed response of delayed type hypersensitivity in tumor bearing mice to normal level. These results suggest that P22A have potential to restore the decreased immune activity of the tumor bearing mice to normal level.

• Journal of Veterinary Clinics
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• v.40 no.5
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• pp.323-329
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• 2023

Peripheral blood-derived mesenchymal stem cells (PB-MSCs) have shown promise in cell-based therapy, as they can be harvested with ease through minimally invasive procedures. This study aimed to isolate PB-MSCs from foals and mares and to compare the proliferation and cellular characteristics of the PB-MSCs between the two groups. Six pairs of mares and their foals were used in this study. MSCs were isolated from PB by direct plating in a tissue culture medium, and cell proliferation (population doubling time [PDT], and colony-forming unit-fibroblast assay [CFU-F]), and characterization (morphology, plastic adhesiveness, colony formation, trilineage differentiation) were examined. There was no significant difference in the PB-MSC yield, CFU-F, and PDT between the mares and foals. PB-MSCs from both mares and foals showed typical MSC characteristics in terms of spindle-shaped morphology, plastic adhesive properties, formation of colonies, trilineage differentiation. These results suggest that PB-MSCs isolated from horses, both adult horses, and foals, can be used for equine cell-based therapy.

• Korean Journal of Microbiology
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• v.24 no.2
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• pp.147-153
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• 1986

Viable potential of Mycobacterium smegmatis, a slow grower in vitro cultivation and of M. leprae, an obligate intracellular parasitic bacterium, which can not be cultured yet in vitro was assessed by fluorospectrophotometry. Bacterial cells in different numbers and under various physiological status were incubater with fluorescein diacetate(FDA). After an incubation of the bacterial preparations with FDA at specified conditions, amount of fluorescein inside bacteria was measured by a fluorospectrophotometer at 470nm and 510nm of excitation and emission wavelengths, respectively. Fluorounit given by such bacteria showed a correlation with assessment of viability of the same preparations made by other methods, such as optical density and colony forming units of M. smegmatis and intracellular ATP content of M. leprae. The possible use of fluorospectrophotometry in assessing viability or physiological potential of bacteria, particularly intracellular parasites and fastidious organisms to culture in vitro is discussed in relation to other methods.

• Journal of the Korea Society of Computer and Information
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• v.21 no.5
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• pp.135-139
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• 2016

Scrophularia ningpoensis hemsl has been traditionally used in China and Vietnam for treatment of bacteria, atopy, pimple, tonsillitis, angina and encephalitis for a long time. The main objectives of this study were to evaluate the antibacterial activity of the Scrophularia ningpoensis hemsl extract on biofilm formation of Klebsiella pneumoniae. Antibacterial activity was conducted using disc diffusion assay and minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) were determined using the broth micro dilution method in accordance to Clinical and Laboratory Standards Institute guidelines(CLSI). Furthermore, cytotoxicity on L929 were assessed using animal cell culture for the proliferation test(MTT cell assay) and the biofilm forming capacity of the K. pneumoniae were determined using the colony forming unit (CFU) assay. The extract exhibited considerable antibacterial activity. K. pneumoniae was susceptible to the extract with the MIC and MBC of 0.1875 and $1.5mg/m{\ell}$ respectively. Cytoxicity test in L929 showed no sign of toxicity at the concentration of $0.75mg/m{\ell}$ and at the same concentration the extract caused inhibition of bacterial biofilm formation. The extract of Scrophularia ningpoensis hemsl possesses an in vitro antibacterial antibiofilm activities against K. pneumoniae, with no sign of cytoxicity on L929.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.5
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• pp.751-760
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• 2021

This study investigated the changes in water quality parameters and microbial colonies when ozone was applied to a semi-recirculating aquaculture system (semi-RAS) for the olive flounder Paralichthys olivaceus (500 g in average weight). Concentrations of ozone-produced oxidants (OPO) in rearing tanks were maintained at 0, 0.014, 0.025 mg/L as Cl₂ for 26 days. Except total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, phosphate phosphorus, chemical oxygen demand, and total suspended solids decreased significantly with increasing OPO concentration in daily and weekly monitoring (P<0.05). Colony forming unit (CFU) counts of heterotrophic marine bacteria decreased in an OPO concentration-dependent manner. Overall reduction rates of microbial colonies in the treatments were 80% higher than those of the control (P<0.05). During the experiment, the OPO concentration-driven ozonation was reliably practiced without any adverse effects on the animals cultured in semi-RAS. Considering the biohazard, operating cost, and stability of ozonation, an OPO concentration of 0.014 mg/L would be sufficient to control water quality parameters and microbial colonies in a semi-RAS.

• Food Science of Animal Resources
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• v.40 no.4
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• pp.668-674
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• 2020

Manuka honey (MH) has been shown anti-bacterial activity against several pathogenic bacteria. However, the inhibitory effect of MH on biofilm formation by Escherichia coli O157:H7 has not yet been examined. In this study, MH significantly reduced E. coli O157:H7 biofilm. Moreover, pre- and post-treatment with MH also significantly reduced E. coli O157:H7 biofilm. Cellular metabolic activities exhibited that the viability of E. coli O157:H7 biofilm cells was reduced in the presence of MH. Further, colony forming unit of MH-treated E. coli O157:H7 biofilm was significantly reduced by over 70%. Collectively, this study suggests the potential of anti-biofilm properties of MH which could be applied to control E. coli O157:H7.

• Journal of Environmental Health Sciences
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• v.39 no.3
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• pp.279-288
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• 2013

Objectives: Effectiveness and conditions of vapor-phase hydrogen peroxide (VPHP) system on decontamination of Geobacillus stearothermophilus(GS) spores, Escherichia coli (E.coli) and Enterobacteria phage felix01 (felix01) were determined. Methods: The VPHP system was designed to vaporize 35% (w/w) solution of hydrogen peroxide, continuously to inject and withdraw VPHP. The system and VHP 1000ED (Steris) were operated such that dehumidification and conditioning were initiated without samples in the chamber. Then the samples were loaded into and removed. Coupons (glass, anodizing, silicon, viton) with GS spores ($1{\times}10^6$ colony forming unit/mL [CFU/mL]), E.coli ($1{\times}10^7$ CFU/mL) and felix01 ($1{\times}10^7$ plaque forming unit/mL[PFU/mL]), and Biological Indicator (BI) with GS spores ($1{\times}10^6$ CFU/mL) on stainless steel coupons were used. The tested samples were sonicated and vortexed, and then were plated for enumeration, followed by incubation at $55^{\circ}C$, 24 hr for GS spores, and at $37^{\circ}C$, 24 hr for E.coli and felix01. BI analysis in broth culture was only qualitative. Results: The efficacy of the VPHP system on decontamination was almost equivalent to that of VHP 1000ED. The conditions for complete decontamination with the VPHP system was as follows: concentration; 700~450 ppm, relative humidity; approximately 55%, and temperature; $34{\sim}32^{\circ}C$. When comparing the decontamination efficiency among different kinds of coupons, glass was the most effective, however, all kinds of coupons were decontaminated completely after 60 min exposure in both systems. Conclusion: The VPHP system can be recommended as an alternative system for traditional system using ethylene oxide, formaldehyde or chlorine dioxide.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.2
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• pp.95-103
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• 2024

Purpose. With the advancement of digital technology, 3D printing is being utilized in the fabrication of denture base. Nevertheless, increasing microbial adhesion to the surface of denture base has been reported as the disadvantage of 3D-printed denture base. The purpose of this study is to investigate the antifungal properties and flexural strength of 3D-printed denture base resin according to the different contents of titanium dioxide nanoparticles. Materials and methods. Titanium dioxide nanoparticles were mixed with the 3D printing resin at the ratios of 0.5, 1, 1.5, and 2 wt%. Twenty specimens per each group were printed in the form of cylindrical shape (diameter: 20 mm, height: 3 mm) to evaluate antifungal properties. Ten specimens from each group underwent polishing using autogrinder, while the remaining ten specimens did not. Candida albicans in hyphae form was inoculated onto each specimen, optical density and colony-forming unit were analyzed. The surface of the specimen was observed using scanning electron microscopy. To evaluate the flexural strength, twenty specimens per each group were 3D printed in the form of rectangular prism shape (length: 64 mm, height: 10 mm, width: 3 mm) and three-point bending tests were conducted using universal testing machine according to ISO 20795-1. Results. Colony-forming unit of C.albicans and optical density of culture medium showed no difference between non-polished groups, but decreased in the polished groups at concentration of 1, 1.5, 2 wt% titanium dioxide nanoparticles. Flexural strength increased with titanium dioxide nanoparticle at concentration of 0.5, 1, 1.5 wt%, but decreased at 2 wt% compared to 1.5 wt%. Conclusion. When 1.5 wt% of titanium dioxide nanoparticles were added to the 3D-printed denture base resin with polishing, antifungal properties were increased.

• The Journal of Advanced Prosthodontics
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• v.6 no.5
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• pp.379-386
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• 2014

PURPOSE. These days, mesenchymal stem cells (MSCs) have received worldwide attention because of their potentiality in tissue engineering for implant dentistry. The purpose of this study was to evaluate various growth inducing factors in media for improvement of acquisition of bone marrow mesenchymal stem cells (BMMSCs) and colony forming unit-fibroblast (CFU-F). MATERIALS AND METHODS. The mouse BMMSCs were freshly obtained from female C3H mouse femur and tibia. The cells seeded at the density of $10^6$/dish in media supplemented with different density of fetal bovine serum (FBS), $1{\alpha}$, 25-dihydroxyvitamin (VD3) and recombinant human epidermal growth factor (rhEGF). After 14 days, CFU-F assay was conducted to analyze the cell attachment and proliferation, and moreover for VD3, the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay was additionally conducted. RESULTS. The cell proliferation was increased with the increase of FBS concentration (P<.05). The cell proliferation was highest at the density of 20 ng/mL rhEGF compared with 0 ng/mL and 200 ng/mL rhEGF (P<.05). For VD3, although the colony number was increased with the increase of its concentration, the difference was not statistically significant (P>.05). CONCLUTION. FBS played the main role in cell attachment and growth, and the growth factor like rhEGF played the additional effect. However, VD3 did not have much efficacy compare with the other two factors. Improvement of the conditions could be adopted to acquire more functional MSCs to apply into bony defect around implants easily.