• YAKHAK HOEJI
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• v.55 no.2
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• pp.168-171
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• 2011

Chrysosplenol C [5,6-dihydroxy-2-(4-hydroxy-3-methoxyphenyl)-3,7-dimethoxychromen-4-one] is a flavonoid found in Miliusa balansae and Pterocaulon sphacelatum. We have recently shown that chrysosplenol C has positive inotropic effect in isolated rat ventricular myocytes. In the present study, we explored a possible mechanism for the positive inotropic effect of chrysosplenol C by examining intracellular $Ca^{2+}$ transients during action potentials. The intracellular $Ca^{2+}$ transients were measured by confocal $Ca^{2+}$ imaging in field-stimulated single rat ventricular myocytes. Chrysosplenol C (50 ${\mu}M$) significantly increased the magnitudes (${\Delta}F/F_0$) of $Ca^{2+}$ transients (control, $1.08{\pm}0.05$; chrysosplenol C, $1.25{\pm}0.03$; n=8, P<0.01). Half decay time of the action potential-induced $Ca^{2+}$ transient was not altered by chrysosplenol C (50 ${\mu}M$) (control, $154{\pm}6$ ms; chrysosplenol C, $167{\pm}11$ ms; n=21). The $Ca^{2+}$ content in the sarcoplasmic reticulum (SR), measured as caffeine (10 mM)-induced $Ca^{2+}$ transient, was significantly decreased by chrysosplenol C (50 ${\mu}M$). These results indicate that chrysosplenol C increases $Ca^{2+}$ transients without altering $Ca^{2+}$ removal kinetics in ventricular myocytes, providing a possible mechanism for its positive inotropic effect.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2309-2317
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• 2009

Depurination, the release of purine bases from nucleic acids by hydrolysis of the N-glycosidic bond, gives rise to alterations of the cell genome. Though cells have evolved mechanisms to repair these lesions, unrepaired apurinic sites have been shown to have two biological consequences: lethality and base substitution errors. 2-Bromopropane (2-BP) is used as an intermediate in the synthesis of pharmaceuticals, dyes, and other organics. In addition, 2-BP has been used as a replacement for chloroflurocarbons and 1,1,1-trichloroethane as a cleaning solvent in electronics industry. However, 2-BP was found to cause reproductive and hematopoietic disorders in local workers exposed to it. Owing to the toxicity of 2-BP, there has been a tendency to use 1-BP as an alternative cleaning solvent to 2-BP. However, 1-BP has also been reported to be neurotoxic in rats. Though $N^7$-guanine adduct of 2-BP has been reported previously, massive depurination of the nucleosides and calf thymus DNA was observed in this study. We incubated the nucleosides (ddG, dG, guanosine, ddA, dA and adenosine) with excess amount 2-BP at the physiological condition (pH 7.4, $37\;{^{\circ}C}$), which were analyzed by HPLC and LC-MS/MS. In addition, the time and dose response relationship of depurination in nucleosides induced by 2-bromopropane at the physiological condition was investigated. Similarly, incubation of calf-thymus DNA with the excess amount 2-BP at the physiological condition was also performed. In addition, the time and dose response relationship of depurination in calf-thymus DNA induced by 2-BP at the physiological condition was investigated. Those results suggest that the toxic effect of 2-BP could be both from the depurination of nucleosides and DNA adduct formation.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.423-427
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• 1992

The volatile components were extracted from kumquat(Fortunella margarita) by simultaneous steam distillation-extraction method and fractionated on silica gel column. The total volatile oil was eluted off first by n-pentane and eluted again by diethyl ether. The total volatile oil and diethyl ether fraction were analyzed by GC and GC-MS. In the total volatile oil, 10 components were identified, of which major ones were limonene(96.5%, of total volatile oil), ${\beta}-pinene$(1.93%) and ${\alpha}-terpineol$(0.42%) and then the characteristic aroma of kumquat appeared to be due to limonene. On the other hand diethyl ether fraction, from which 46 components were identified, contained 9 alcohols, 22 terpenes and terpene alcohols, 7 aldehydes and ketones, 7 esters and 1 miscellaneous components. The major components were ${\alpha}-terpineol$(31.98% of diethyl ether fraction), ${\beta}-terpineol$(7.37%), geranyl acetate(9.69%) and p-menthadien-9-ol(4.12%).

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.3
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• pp.229-235
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• 2013

Among several animal models of retinitis pigmentosa (RP), the more recently developed rd10 mouse with later onset and slower rate of retinal degeneration than rd1 mouse is a more suitable model for testing therapeutic modalities. We therefore investigated the time course of retinal degeneration in rd10 mice before adopting this model in our interventional studies. Electroretinogram (ERG) recordings were carried out in postnatal weeks (PW) 3~5 rd10 (n=23) and wild-type (wt) mice (n=26). We compared the amplitude and implicit time of the b-wave of ERG records from wt and rd10 mice. Our results showed that b-wave amplitudes in rd10 mice were significantly lower and the implicit time of b-waves in rd10 mice were also significantly slower than that in wt mice ($20{\sim}160{\mu}V$ vs. $350{\sim}480{\mu}V$; 55~75 ms vs. 100~150 ms: p<0.001) through PW3 to PW5. The most drastic changes in ERG amplitudes and latencies were observed during PW3 to PW4. In multichannel recording of rd10 retina in PW2 to PW4.5, we found no significant difference in mean spike frequency, but the frequency of power spectral peak of local field potential at PW3 and PW3.5 is significantly different among other age groups (p<0.05). Histologic examination of rd10 retinae showed significant decrease in thickness of the outer nuclear layer at PW3. TUNEL positive cells were most frequently observed at PW3. From these data, we confirm that in the rd10 mouse, the most precipitous retinal degeneration occurs between PW3~PW4 and that photoreceptor degeneration is complete by PW5.

• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.543-548
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• 1990

Volatile components of fresh apricot (Prunus armeniaca var. ansu Max.) were isolated by simultaneous distillation-extraction at two different pH values of 3.1 and 7.0 and by headspace trapping method. The volatiles were analyzed by GC and GC-MS. A total of 80 components were identified in the three aroma concentrates, including 9 naphthalene derivatives that were not previously reported in apricot. Of components identified in native pH (3.1) sample, the major components were aliphatic $C_6$ aldehydes and alcohols, monoterpene alcohols, benzyl alcohol, ${\beta}-phenylethyl$ alcohol and naphthalene derivatives, while those in neutral pH(7.0) sample and headspace volatiles were aliphatic $C_6$ aldehydes and alcohols. Simultaneous distillation-extraction at pH 3.1 was significantly increased the concentration of n-hexanal, trans-2-hexenal, cis-3-hexen-1-ol, linalool oxide, linalool, ${\alpha}-terpineol$, nerol, geraniol, benzyl alcohol, ${\beta}-phenylethyl$ alcohol and naphthalene derivatives. These results demonstrate that above the components are present in glycosidically bound forms in apricot.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.4
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• pp.826-832
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• 2004

A CMOS 8 bit folding and interpolating ADC for an embedded system inside VLSI is presented in this paper. This folding ADC uses the 2 stage architecture for improving of nonlinearity. repeating the folding and interpolating twice. At a proposed structure, a transistor differential pair operates on the second folder. A ADC with 2 stage architecture reduces the number of comparators and resisters. So it is possible to provide small chip size, low power consumption and high operating speed. The design technology is based on fully standard 0.25m double-Poly 2 metal n-well CMOS Process. The simulated Power consumption is 45mW with an applied voltage of 2.5V and sampling frequency of 250MHz. The INL and DNL are within <ㅆㄸㅌ>$\pm$0.2LSB, respectively. The SNDR is approximately 45dB for input frequency of 10MHz.

• Analytical Science and Technology
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• v.15 no.6
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• pp.489-495
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• 2002

In this study, we determined distribution status of organonitrogen pesticides such as trifluralin, atrazine, metribuzin, alachlor, malathion, nitrofen, permethrin, cypermethrin, fenvalerate, and parathion accumulated in the fresh water fishes and amphibians. We collected those samples at 31 sites from the basin of major rivers, and separated the muscular tissue as a final sample for analysis. In the pretreatment process, lipid was eliminated by using acetonitrile and n-hexane, and pesticides were reextracted with dichloromethane. The extract was dehydrated and concentrated, and then cleaned it up by passing the Florisil column, and pesticide content was finally determined by using a GC-MS system after introducing isotope labelled references. The accumulation level was observed in the range of $0.17{\sim}6.8{\mu}g/kg$ in amphibians and $0.26{\sim}16{\mu}g/kg$ in fishes including cypermethrin as $16{\mu}g/kg$.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.103-107
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• 2012

Acanthopanax sessiliflorus Seeman fruits (Araliaceae) were extracted at room temperature with 70% aqueous ethanol (EtOH). The concentrated extract was partitioned with ethyl acetate (EtOAc), n-butyl alcohol, and $H_2O$, successively. From the EtOAc fraction, four compounds were isolated through the repeated silica gel and octadecyl silica gel (ODS) column chromatographies. According to the results of physico-chemical and spectroscopic data including NMR, IR, and gas chromatography/mass spectrometer, the chemical structures of the compounds were determined as stigmasterol (1), linoleic acid (2), ${\beta}$-sitosterol (3), and stigmast-5-en-$3{\beta}$,$7{\beta}$-diol (4).

• Applied Biological Chemistry
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• v.51 no.1
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• pp.60-64
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• 2008

The aerial parts of Spathiphyllum cannifolium were extracted with 80% aqueous MeOH and the concentrated extract was partitioned with EtOAc, n-BuOH and $H_2O$, successively. From the EtOAc fraction, three compounds were isolated through the repeated silica gel, ODS, Sephadex LH-20 column chromatographies. From the results of physico-chemical data including NMR, MS and IR, the chemical structures of the compounds were determined as stigmasterol (1), $(2S)1-O-linolenoyl-2-0-myristoyl-3-0-{\beta}-D-galactopyranosyl-sn-glycerol$ (2) and stigmasterol glucoside (3). They were the first to be isolated from Spathiphyllum cannifolium.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1234-1243
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• 2000

A method for quantitative determination of styrene dimer and trimer, which are suspected as endocrine disruptors, in foods and containers was studied. For residual contents of styrene dimer and trimer in two-kinds of containers, which contained instant noodle and yogurt, sample pieces were completely dissolved in tetrahydrofuran. The polymer was precipitated with n-hexane, a portion of supernatant was concentrated for analysis. A sensitive method was also optimized for the quantification of styrene dimer and trimer in foods such as instant cup noodle and yogurt by using GC/MS. Limits of Detection were about 3.2-87.0 ppb for styrene dimers and trimers. The highest recovery was obtained by extraction with acetone/hexane(1:1), followed by florisil clean-up. The levels of styrene dimer and trimer migrated by food simulants were much higher in heptane.