• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.165-170
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• 2007

In this work, caffeine and some catechin compounds such as +C, EGC and EGCG were extracted from green tea using quercetin molecular imprinted polymers in solid-phase extraction. For synthesis of MIP, quercetin as the templates, MAA as the monomer, EGDMA as the crosslinker and AIBN as the initiator were used. For extraction of caffeine and catechin compounds from green tea, the solid-phase extractions of a load followed by wash and elution procedures were done with water, methanol and methanol:acetic acid=90:10 (vol.%) as the solvents, respectively. HPLC analysis (C18 column, 5 μm, 250×4.6 mm) with the mobile phase of methanol:water=40:60 (vol.%) at a flow rate of 0.5 ml/min was adopted for the quantitative determination. By solid-phase extraction, the resolutions of caffeine and some catechin compounds from green tea were increased. The quercetin-MIP had higher selectivity to +C compounds.

• Advances in Traditional Medicine
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• v.3 no.2
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• pp.100-105
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• 2003

Systematic analysis of caffeine from the commercial samples of Indian tea leaves was performed by a routine method and the content of caffeine was found to be 19.0-37.4 mg/100 g leaves. The caffeine contents from coffee seeds and chicory from Indian origin were analyzed and found to be 0.6540-1.4920 g/100 g seeds. Caffeine contents of roasted Indian chicory roots were lower than either those of Indian tea leaves or Indian coffee seeds. The multidrug resistance (MDR) reversing effects were tested on a mouse leukemia cell line of L-5178 cells by methanol extracts [M1-M15] of Indian tea leaves and coffee seeds, comparing to a control of $({\pm})-verapamil$. The effects were measured by fluorescence ratio between treated and untreated group cells. Among fifteen methanol extracts, a Gemini tea [M6] (fluorescence activity ratio 5.26) had the most potent effect for L-5178 cells. The extract M6 was 0.63-fold of $({\pm})-verapamil$. We suggest that one of mechanisms of reversal by M6 might have strong affinity to dopamine $D_1$ and D_2$ receptors. Further studies with many more tumor and normal cell lines are necessary to confirm the MDR reversal specificity of coffee methanol extracts.

• Animal cells and systems
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• v.1 no.1
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• pp.77-80
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• 1997

DOantrolene is a primary specific therapeutic drug for prevention and treatment of malignant hyperthermia symptoms. The mechanisms underlying the therapeutic effects of the drug are not well understood. The present study aimed at the characterization of the effects of azumolene, a water soluble dantrolene analogue, on ryanodine binding to sarcoplasmic reticulum (SR) from normal and malign::lnt hyperthermia susceptible (MHS) swine muscles. Characteristics of $[^3H]ryanodine$ binding were clearly different between the two types of SR. Kinetic analysis of eH]ryanodine binding to SR in the presence of $2{\mu}M$ $Ca^{2+}$ showed that association constant $(K_{ryanodine}_7$ is significantly higher in MHS than normal muscle SR $(2.83 vs. 1.32{\times}10^7 M^{-1}$, whereas the maximal ryanodine binding capacity $(B_{max})$ is similar between the two types of SR. Addition of azumolene $(e.g. 400{\mu}M)$ did not significantly alter both $K_{ryanodine}$ and $B_{max}$ of $[^3H]$ryanodine binding in both types of SR, indicating that the azumolene effect was not on the ryanodine binding sites. Addition of caffeine activated $[^3H]$ ryanodine binding in both types of SR, and caffeine sensitivity was significantly higher in MHS muscle SR than normal muscle SR $(K_{caffeine}:3.24 vs. 0.82 {\times} 10^2 M^{-l}). Addition of azumolene $(e.g.400{\mu}M)$ decreased Kcaffeine without significant change in $B_{max}$ in both types of SR suggesting that azumolene competes with caffeine binding site(s). These results suggest that malignant hyperthermia symptoms are caused at least in part by greater sensitivity of the MHS muscle SR to the $Ca^{2+}$ release drug(s), and that azumolene can reverse the symptoms by reducing the drug affinity to $Ca^{2+}$ release channels.

• Journal of Convergence for Information Technology
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• v.9 no.6
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• pp.35-43
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• 2019

This study was conducted in order to identify consumption and experience of adverse effects of high-caffeine energy drink among high school students. This study was a descriptive survey including 245 students in D city. Data were analyzed using descriptive statistics and ${\chi}^2$ test. In the results, 79.5% of the students had previous experience of energy drink consumption. 50.6% of students were experienced adverse effects, mainly palpitation. Among the general characteristics, there was a significant difference according to the experience of high-caffeine energy drink consumption depending on monthly allowance(p=.019) and drinking(p=.033), and a significant difference from adverse effects depending on gender(p=.001) and health condition(p=.006). Also, there was a significant difference according to the experience of adverse effects depending on drinking reason(p=.040) and drinking time(p=.005). After, policy measures are needed to limit the sale of high-caffeine energy drinks and continuous health education is needed to foster the ability of students to control themselves.

• Korean Journal of Exercise Nutrition
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• v.13 no.1
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• pp.75-81
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• 2009

This study aims to find out the effect of ingestion of 3 mg·kg^-1 caffeine on fluid-electrolyte balance and Tty change during exercise under heat environment of 30~32℃ (40-50% humidity). Five trained males who routinely trained for approximately 60 min·d^-1, 3-6 d·wk^-1 (age; 28.20±3.56yrs, height; 174.56±5.46 cm, body mass; 76.13±9.02 kg, body fat(%); 14.24±3.99, VO₂max; 54.00±4.30 mL·kg^-1·min^-1, exercise career; 4.20±1.95yrs) performed 40min of treadmill running in heat chamber. The study was a double-blind, randomized, crossover design. Body mass change following exercise was higher for the PLAC (Placebo) and CAFF (Caffeine) in comparison to the CON (Control), there was no significant difference between the CAFF, PLAC, CON (p= .997). The U_sg not significant differences (p= .731) and Osm_urine not significant differences between the CAFF, PLAC, CON (p= .901). There also were not significant between the CAFF, PLAC, CON for [Na⁺]_urine and [K⁺]_urine (p= .928, p= .469). In the case of Tty, although the increase rate of Tty was the highest for the CAFF on exercise early, exercise the second half in comparison to the CON and PLAC, there was not significant interaction effect between the CAFF, PLAC, and CON of Tty (p= .067), In conclusion, it was confirmed that the 3 mg·kg^-1 caffeine ingestion prior to exercising in heat environment does not impart negative effect on body fluid, electrolyte balance and changes in Tty.

• The Korean Journal of Pharmacology
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• v.24 no.2
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• pp.197-201
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• 1988

Effects of high concentration of KC1 and caffeine on cytosolic $Ca^{2+}$ level $([Ca^{2+}]_{cyt})$, measured simultaneously with muscle tension using a fluorescent intracellular $Ca^{2+}$ indicator fura 2, were examined in isolated smooth muscle of rat aorta. High $K^+$ (72.7 mM) solution induced sustained increase in both $([Ca^{2+}]_{cyt})$ and tension. In contrast to this, caffeine (20 mM) induced a rapid increase in $([Ca^{2+}]_{cyt})$ followed by a decrease to a level which was higher than the resting level. However, muscle tension showed only a transient increase followed by a decrease below the resting level. In a $Ca^{2+}-free$ solution, high $K^+-induced$ neither $([Ca^{2+}]_{cyt})$ nor tension, whereas caffeine induced a transient increase in both $([Ca^{2+}]_{cyt})$ and muscle tension. These results suggest that high $K^+-induced$ contraction in vascular smooth muscle of rat aorta is due to $Ca^{2+}$ influx whereas caffeine-induced contraction is due to $Ca^{2+}$ release from cellular store. Further, caffeine seems to have an additional effect to decrease the sensitivity of the contractile elements to $Ca^{2+}$.

• Journal of the Korean Society of School Health
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• v.27 no.1
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• pp.31-38
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• 2014

Purpose: The purpose of this study was to identify the relationship between caffeinated beverage intake and sleep quality among university students. Methods: Data were collected through a survey of 262 university students in Ulsan conducted in Nov. 27 2013. The survey used a self-administered questionnaire, which was composed of questions regarding socio-demographic characteristics, sleep quality and the status of caffeinated beverage intake. The collected data were analyzed by descriptive statistics, pearson correlation analysis and multiple regression analysis, using SPSS/WIN 21 Program. Results: In average, The subjects consumed 6.43 cups of caffeinated beverage per week, intaking 397.60mg of caffeine. The correlations between sleep quality and the amount of caffeinated beverage intake and between sleep quality and the quantity of caffeine intake were statistically significant. By performing a multiple regression analysis, it was shown sleep quality decreased significantly as the amount of caffeine intake increased (p<.001). Conclusion: To improve university students' sleep quality, it is necessary to control their intake of caffeinated beverage.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.6
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• pp.431-436
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• 2011

Vascular smooth muscle cells can obtain a proliferative function in environments such as atherosclerosis in vivo or primary culture in vitro. Proliferation of vascular smooth muscle cells is accompanied by changes in ryanodine receptors (RyRs). In several studies, the cytosolic $Ca^{2+}$ response to caffeine is decreased during smooth muscle cell culture. Although caffeine is commonly used to investigate RyR function because it is difficult to measure $Ca^{2+}$ release from the sarcoplasmic reticulum (SR) directly, caffeine has additional off-target effects, including blocking inositol trisphosphate receptors and store-operated $Ca^{2+}$ entry. Using freshly dissociated rat aortic smooth muscle cells (RASMCs) and cultured RASMCs, we sought to provide direct evidence for the operation of RyRs through the $Ca^{2+}$- induced $Ca^{2+}$ -release pathway by directly measuring $Ca^{2+}$ release from SR in permeabilized cells. An additional goal was to elucidate alterations of RyRs that occurred during culture. Perfusion of permeabilized, freshly dissociated RASMCs with $Ca^{2+}$ stimulated $Ca^{2+}$ release from the SR. Caffeine and ryanodine also induced $Ca^{2+}$ release from the SR in dissociated RASMCs. In contrast, ryanodine, caffeine and $Ca^{2+}$ failed to trigger $Ca^{2+}$ release in cultured RASMCs. These results are consistent with results obtained by immunocytochemistry, which showed that RyRs were expressed in dissociated RASMCs, but not in cultured RASMCs. This study is the first to demonstrate $Ca^{2+}$ release from the SR by cytosolic $Ca^{2+}$ elevation in vascular smooth muscle cells, and also supports previous studies on the alterations of RyRs in vascular smooth muscle cells associated with culture.

• Korean Journal of Veterinary Research
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• v.36 no.4
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• pp.795-807
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• 1996

This study was conducted to identify the effects of caffeine on the lipid and protein components or blood chemistry levels of the serum as well as the total homogenate, mitochondrial and microsomal fraction of the rat(Sprague-Dawley, female) liver. Acute test were conducted to determine those effects. The acute test was conducted by dividing rats into 7 groups according to the time lapsed after a single oral administration of 100mg/kg caffeine(that is control, 2hrs, 4hrs, 8hrs, 24hrs, 48hrs and 72hrs lapsed group). The concentrations of glucose, urea nitrogen, uric acid, creatinine, total protein, albumin, A/G ratio, triglyceride, total cholesterol, HDL-cholesterol, free fatty acid, phospholipid as well as the activities of alanine aminotransferase(ALT), aspartate aminotransferase(AST) and alkaline phosphatase(ALP) were measured in the serum of each experimental groups. The concentrations of the carbonyl group, malondialdehyde(MDA) and the patterns of the SDS-PAGE(Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis) were analyzed to determine the oxidative damages and metabolic changes on the lipid and protein components in the serum, and total homogenate, mitochondrial and microsomal fractions of the rat liver. The results obtained from this study were summarized as follows; 1. The concentrations of serum glucose were significantly higher(p<0.01) between 4(143.0mg/dl) and 8hrs(138.0mg/dl) in comparison to that of the control(101.1mg/dl) after a single oral administration of caffeine(100mg/kg). While on the other, there were no significant differences in the concentrations of urea nitrogen, uric acid, creatinine, total protein, albumin and albumin/globulin(A/G) ratio in comparison to those of the control. 2. The concentrations of total cholesterol and HDL-cholesterol in serum were significantly higher(p<0.01) between 4(77.4mg/dl, total cholesterol) and 8hrs(64.7mg/dl, HDL-cholesterol) in comparison to those of the control(62.8, 46.7mg/dl) after a single oral administration of caffeine(100mg/kg). On the other hand, the concentrations of triglyceride in serum were significantly lower(p<0.01) after 8hrs(38.8mg/dl) in comparison to that of the control(66.5mg/dl). 3. The activities of AST in serum was significantly higher(p<0.05) from 2hrs(149U/L) to 8hrs(178U/L) in comparison to the control(112U/L) after a single oral administration of caffeine(100mg/kg). The activities of ALT in serum were significantly higher(p<0.01) at 4(45.5U/L), 24(49.3U/L), 48(46.8U/L) and 72 hrs(42.3U/L) in comparison to that of the control(39.7U/L) after a single oral administration of caffeine(100mg/kg). On the other hand, there were no significant differences in the activities of ALP in comparison to that of the control. 4. The concentrations of free fatty acid in serum were significantly higher(p<0.01) at 8hrs(65.0mg/dl) in comparison to that of the control(37.6mg/dl) after a single oral administration of caffeine(100mg/kg). However, there were no significant differences in the concentrations of carbonyl group and malondialdehyde within serum, and liver homogenate, mitochondrial and microsomal fractions in comparison to that of the control. 5. The patterns of SDS-PAGE in serum, mitochondrial and microsomal fraction of the liver showed no significant differences.

• Korean Journal of Human Ecology
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• v.7 no.1
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• pp.197-203
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• 1998

The recognition thresholds of sucrose, NaCl, citrate, caffeine, and MSG solution were determined and the effects of MSG on four basic tastes were also investigated by the sensory evaluation. The recognition threshold of sucrose was 0.451%, NaCl 0.01%, caffeine 0.005%, citrate 0.004%, and MSG 0.033%. When MSG was added to 10% sucrose solution, the intensity of sweetness significantly decreased by 0.8% MSG. The sweetness of sucrose indicated the decreasing tendency according to the addition of MSG. When MSG was mixed with NaCl solution, the intensity of saltiness significantly increased. With an addition of MSG to the citrate solution, sourness was suppressed. The bitterness increased slightly in a caffeine solution when mixed with MSG.