• The Korean Journal of Physiology and Pharmacology
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• v.16 no.1
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• pp.37-42
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• 2012

The aim of the present study was to elucidate the direct effects of melatonin on bladder activity and to determine the mechanisms responsible for the detrusor activity of melatonin in the isolated rat bladder. We evaluated the effects of melatonin on the contractions induced by phenylephrine (PE), acetylcholine (ACh), bethanechol (BCh), KCl, and electrical field stimulation (EFS) in 20 detrusor smooth muscle samples from Sprague-Dawley rats. To determine the mechanisms underlying the inhibitory responses to melatonin, melatonin-pretreated muscle strips were exposed to a calcium channel antagonist (verapamil), three potassium channel blockers [tetraethyl ammonium (TEA), 4-aminopyridine (4-AP), and glibenclamide], a direct voltage-dependent calcium channel opener (Bay K 8644), and a specific calcium/calmodulin-dependent kinase II (CaMKII) inhibitor (KN-93). Melatonin pretreatment ($10^{-8}{\sim}10^{-6}M$) decreased the contractile responses induced by PE ($10^{-9}{\sim}10^{-4}M$) and Ach ($10^{-9}{\sim}10^{-4}M$) in a dose-dependent manner. Melatonin ($10^{-7}M$) also blocked contraction induced by high KCl ($[KCl]_{ECF}$; 35 mM, 70 mM, 105 mM, and 140 mM) and EFS. Melatonin ($10^{-7}M$) potentiated the relaxation response of the strips by verapamil, but other potassium channel blockers did not change melatonin activity. Melatonin pretreatment significantly decreased contractile responses induced by Bay K 8644 ($10^{-11}{\sim}10^{-7}M$). KN-93 enhanced melatonin-induced relaxation. The present results suggest that melatonin can inhibit bladder smooth muscle contraction through a voltage-dependent, calcium-antagonistic mechanism and through the inhibition of the calmodulin/CaMKII system.

• Korean Journal of Food Science and Technology
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• v.49 no.5
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• pp.538-543
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• 2017

Astringent persimmon (Diospyros kaki Thunb. cv. Cheongdo-Bansi) peel with the astringency removed, which is a by-product of dried persimmon (gotgam), was investigated for its antioxidant and neuroprotective properties. A mixture of peel and 40% (v/v) aqueous ethanol was subjected to ultrasonication and then thermal and nonthermal treatments, to produce thermally-treated and nonthermally-treated persimmon peel extracts (TPE and NTPE, respectively). The total phenolic and flavonoid contents and the antioxidant capacity of TPE was approximately 1.3-1.8 times higher than those of NTPE. TPE resulted in the increased viability of neuronal PC-12 cells compared with NTPE. Furthermore, intracellular oxidative stress in PC-12 cells was more decreased by treatment with TPE than NTPE. Cholinesterases, such as acetylcholinesterase and butyrylcholinesterase, were more inhibited by treatment with TPE than NTPE. These results suggest that TPE is useful as a functional material to decrease oxidative stress in neuronal cells and to inhibit cholinesterases.

• The Korean Journal of Mycology
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• v.47 no.1
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• pp.75-81
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• 2019

The goal of this study was to characterize unrecorded wild yeasts from soils of spices plants fields and further, to elucidate its anti-demential activities and tyrosinase inhibitory activity. Piskurozyma taiwanensis R4-1 (NIBRFGC000502619), Nadsonia starkeyi-henricii R6-2 (NIBRFGC000502618), and Canadida friedrichii M12-6 (NIBRFGC000502615) isolated from soil of garlic field represented newly recorded yeast strains in Korea. Vishniacozyma peneaus I2-9 (NIBRFGC000502617) and Cryptococcus aspenensis I21-1 (NIBRFGC000502616) from soil of ginger field represented also newly recorded yeast strains, and microbiological characteristics of its fifteen yeast strains were investigated. All of these unrecorded yeasts exhibited oval-global shape and have ascospores except Canadida friedrichii M12-6. Piskurozyma taiwanensis R4-1 and Canadida friedrichii M12-6 grew well in vitamin-free medium, and Piskurozyma taiwanensis R4-1 was halotolent growing in 10% NaCl-containing yeast extract peptone dextrose (YPD) broth. After prepared cell-free of the unrecorded wild yeasts, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities as anti-dementia activity and tyrosinase inhibitory activity as whitening activity were determined. Cell-free extract from Canadida friedrichii M12-6 had the highest tyrosinase inhibitory activity of 14.4%.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.1
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• pp.125-140
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• 2023

Careful preparation for a start-up can lower the risk of failure and create a successful business model. However, there are still challenges for middle-aged entrepreneurs, as start-up services and policies are often not readily accessible or fully utilized. Despite active research on middle-aged start-ups, previous studies have not delved deeply into the demographics of start-up preparation and various preparation behaviors. In response to this, a study was conducted to identify which start-up support services middle-aged entrepreneurs use, and how start-up preparation can be classified based on this. Data from 324 middle-aged tech start-up owners, based in Seoul and who started their businesses within the past 7 years, was collected and analyzed. The results showed that middle-aged entrepreneurs had moderate start-up preparation, with the greatest focus on the preparation period and the least focus on start-up education. Latent Profile Analysis revealed three groups of start-up preparation types among middle-aged entrepreneurs: "Overall Tribal Type," "Lack of Start-up Education Type," and "Comprehensive Preparation Type." BCH was performed on start-up satisfaction, start-up competence, fear of failure, access to start-up services, and support needs for middle-aged entrepreneurs based on the preparation type. The results showed that "Overall Tribal Type" had statistically lower start-up satisfaction, competence, and service accessibility compared to the other groups. Meanwhile, "Comprehensive Preparation Type" had a statistically lower fear of failure than the other types. "Overall Tribal Type" also had lower accessibility to middle-aged start-up services. All types had a high recognition of the need for support for specialized middle-aged start-ups. The findings highlight the need for more comprehensive support for middle-aged entrepreneurs. This could include expanding support projects to enhance their level of preparation, providing customized support based on their level of preparation, and improving the visibility and accessibility of start-up support services for middle-aged individuals. Additionally, specialized education that addresses the characteristics of middle-aged individuals should be provided.