• Reproductive and Developmental Biology
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• v.32 no.4
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• pp.237-243
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• 2008

The objective of this study was to examine the effect of caffeine and sodium bicarbonate in a fertilization medium on the fertilizability of boar spermatozoa that were frozen in straws. Boar spermatozoa were extended with Beltsville F5 extender and frozen in 0.25-ml straws. In vitro matured porcine oocytes were fertilized in vitro (IVF) with frozen-thawed boar spermatozoa for 6h in a modified tris-buffered medium (mTBM) or in its modified medium by substituting the tris with 25mM sodium bicarbonate (modified bicarbonate-buffered medium; mBBM). Some of inseminated oocytes were fixed and stained for examination of sperm penetration. IVF embryos were cultured in a North Carolina State University-23 medium for embryo development. The percentage of live sperm was $47{\pm}4%$ and morphological abnormality of acrosome was found in $14{\pm}3%$ of spermatozoa. Optimal sperm concentration for IVF was $0.75{\sim}1.0{\times}1.0{\times}10^6$ sperms/ml when mTBM containing 5mM caffeine was used as the fertilization medium. Sperm penetration was significantly (p<0.05) stimulated by increasing caffeine concentration in the IVF medium. In addition, mBBM significantly (p<0.05) increased sperm penetration (92%) compared to mTBM (65%). More (p<0.05) blastocysts (22% vs. 32%) developed from the oocytes that were fertilized in mBBM containing 1mM caffeine than from those fertilized in mTBM with 5mM caffeine. Our results indicate that boar spermatozoa can be frozen successfully in straws with holding their normal fertilizability and that caffeine and sodium bicarbonate stimulates sperm penetration in vitro.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.981-989
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• 2019

Coffee is a popular beverage worldwide, and the scale of consumption is growing rapidly. Many studies have shown that increased coffee consumption has various effects on human health, including beneficial effects on liver diseases, clinical type 2 diabetes, and Parkinson's disease. However, the influences of coffee or caffeine (a component of coffee) on the gut microbiota have not been examined in detail. Here, we tested whether caffeine could alter the antimicrobial activity of L. casei against E. coli. Interestingly, we found that treatment with 0.3 mg/mL caffeine increased the antimicrobial activity of L. casei against E. coli. This activity was not associated with the release of lactic acid but did appear to be related to a heat-labile factor present in the L. casei culture supernatant. Our analyses suggest that the putative antimicrobial factor found in the culture supernatant of L. casei treated with caffeine may be bacteriocin. Taken together, our results suggest that caffeine, which is an ingredient of coffee, increases the antimicrobial activity of L. casei against E. coli through the enhanced production of bacteriocin. These findings also suggest that coffee consumption affects the ability of beneficial bacteria to decrease pathogenic bacteria and/or prevent the progression of bacterial infection-associated diseases in the gut.

• The Journal of Internal Korean Medicine
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• v.29 no.3
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• pp.778-786
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• 2008

Objectives : This study was to investigate the short time effect of caffeine on heart rate variability(HRV) and the effect of Neiguan(PC6) acupuncture stimulation on HRV. Methods : 27 healthy adult volunteers were randomly allocated to two groups: Neiguan group (N=13) or placebo group (N=14). The study was carried out under a randomized double-blinded placebo-controlled trial method. Each group orally received the same tablets with 200 mg caffeine. After 1 hour, acupuncture was applied to the Neiguan(PC6) points for the Neiguan group, and for the placebo group was applied to a non-acupuncture point. Both groups were estimated with HRV 3 times, before and after caffeine ingestion, 20 minutes after acupuncture stimulation. Results : After taking caffeine, pulse rate, mean-HRV, and pNN50(the proportion derived by dividing NN50 by the total number of NN intervals) decreased, SDNN(standard deviation of all normal-to-normal (NN) intervals), RMSSD (the root square of successive differences), TP log, HF(high frequency), and HRV index was increased. There were significant changes to the autonomic nervous system after taking caffeine. There were no significant differences between the two groups after acupuncture at Neiguan. Conclusion : Caffeine could induce general activation of the autonomic nervous system. Neiguan acupuncture stimulation may not have significant influence on the autonomic nervous system.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.313-322
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• 1998

In a myocyte freshly isolated from rabbit cerebral artery, the characteristics of $Ca^{2+}$ release by histamine or caffeine were studied by microspectrofluorimetry using a $Ca^{2+}-binding$ fluorescent dye, fura-2. Histamine (5 ${\mu}M$) or caffeine (10 mM) induced a phasic rise of cytoplasmic free $Ca^{2+}$ concentration $([Ca^{2+}]_C)$ which could occur repetitively with extracellular $Ca^{2+}$ but only once or twice in $Ca^{2+}-free$ bathing solution. Also, the treatment with inhibitor of sarcoplasmic reticulum $Ca^{2+}-ATPase$ suppressed the rise of $[Ca^{2+}]_C$ by histamine or caffeine. In $Ca^{2+}-free$ bathing solution, short application of caffeine in advance markedly attenuated the effect of histamine, and vice versa. In normal $Ca^{2+}-containing$ solution with ryanodine (2 ${\mu}M$), the caffeine-induced rise of $[Ca^{2+}]_C$ occurred only once and in this condition, the response to histamine was also suppressed. On the other hand, in the presence of ryanodine, histamine could induce repetitive rise of $[Ca^{2+}]_C$ while the amplitude of peak rise became stepwisely decreased and eventually disappeared. These results suggest that two different $Ca^{2+}-release$ mechanisms (caffeine-sensitive and histamine-sensitive) are present in rabbit cerebral artery myocyte and the corresponding pools overlap each other functionally. Increase of $[Ca^{2+}]_C$ by histamine seems to partially activate ryanodine receptors present in caffeine-sensitive pool.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.1
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• pp.49-56
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• 1994

This study was undertaken to investigate the effect of caffeine level on food intake and weight gain in 120 Sprague-Dawley rats of different ages and sexes for 3 weeks. The results were as following : the food intake of caffeine group was significantly lower than that of caffeine free group in young and adult rata(p<0.05). The bo여 weight gain, body weight gain efficiency ratio and food efficiency ration of rats were not significantly different between two groups. The results showed that body weight gain was not affected by increased caffeine level in young and adult rats.

• Clinical and Experimental Reproductive Medicine
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• v.39 no.4
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• pp.144-152
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• 2012

Objective: Concerns are growing about the decrease in male reproductive health. Caffeine is one of the popular nutrients that has been implicated as a risk factor for infertility. In the present study, we examined whether in utero and lactational exposure to caffeine affects the reproductive function of the offspring of rats. Methods: Pregnant rats received caffeine via drinking water during gestation (26 and 45 mg/kg) and lactation (25 and 35 mg/kg). Body and reproductive organ weight, seminiferous tubule diameter, germinal epithelium height, sperm parameters, fertility rate, number of implantations, and testosterone level of the offspring were assessed from birth to adulthood. Results: Significant dose-related decreases were observed in the body and reproductive organ weight, seminiferous tubule diameter, and germinal epithelium height of the offspring. Sperm density had declined significantly in offspring of the low-dose and high-dose groups, by 8.81% and 19.97%, respectively, by postnatal day 150. The number of viable fetuses had decreased significantly in females mated with male offspring of the high-dose group at postnatal days 60, 90, 120, and 150. There were also significant reductions in testosterone levels of high-dose group offspring from birth to postnatal day 150. Conclusion: It is concluded that maternal caffeine consumption impairs gonadal development and has long-term adverse effects on the reproductive efficiency of male offspring rats.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.901-905
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• 2000

An experiment was conducted to investigate the effect of caffeine, cAMP and cattle seminal plasma on preservation of semen at ultra low temperature ($-196{^{\circ}C}$). Each semen sample was divided into four parts equal in volume and sperm concentration; three were treated with caffeine, or cAMP, or cattle seminal plasma (CSP) and the fourth was kept as control. Sperm motility, abnormal spermatozoa, live-dead count and acrosomal damage were studied at different stages of freeze preservation viz.; just after dilution, at $5{^{\circ}C}$, at glycerolisation, before freezing, just after freezing, 24 hours of storage, and one week of storage. Sperm motility (58.39, 61.33, 52.00 and 50.39 per cent), non-eosinophilic spermatozoa (72.55, 69.98, 63.31 and 67.64 per cent), abnormal spermatozoa (5.71, 4.98, 8.04 and 5.66 per cent) and acrosomal damage (13.28, 13.33, 14.80 and 14.65 per cent) were observed in cAMP, caffeine, cattle seminal plasma and control, respectively, at every stage of freeze preservation. From this study it could be concluded that freezability of buffalo semen can be improved through the addition of caffeine followed by cAMP and cattle seminal plasma.

• Journal of the Korean Society of School Health
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• v.37 no.1
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• pp.33-41
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• 2024

Purpose: This study aims to investigate the factors associated with high-caffeine drink consumption among Korean adolescents. Methods: Secondary data analysis was conducted utilizing the 18th Korea Youth Risk Behavior Survey, with a total enrollment of 51,850 students. Descriptive statistics, x² tests, and multivariate logistic regression were performed using SPSS 23.0. Results: The study identified several factors associated with high-caffeine drink consumption, including school levels, tobacco or alcohol consumption, walking, perceived stress levels, feelings of sadness, loneliness, and anxiety, and the occurrence of suicidal thoughts. Conclusion: The findings suggest there is an association between unhealthy health behaviors or mental health issues, and consumption of high-caffeine drinks among adolescents. It emphasizes the need for increased attention and targeted educational interventions for adolescents at high risk.

• YAKHAK HOEJI
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• v.57 no.2
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• pp.110-118
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• 2013

High-caffeine energy drink consumption has been increasing in young adults, frequently causing the most common symptoms such as tremor, insomnia, anxiety, and nervousness and rarely leading to serious adverse effects like seizure, acute mania, and stroke due to caffeine overdose. There have been little current studies regarding analysis of high-caffeine energy drink consumption and its adverse effects in Korea. This study was to examine high-caffeine consumption patterns, associated factors, and adverse effects based on responses from 231 college students in a University through survey. About 88.3% (n=204) of total respondents reported that they had energy drinks. College students mostly consumed energy drinks to keep awake (46%) when studying and to recover fatigue (27%). Approximately 44% respondents mainly reported palpitation (73.9%) and insomnia (72.8%) regarding adverse effect questionnaire. Current reports on the risk of recreational use, co-ingestion of alcohol and energy drink as well as energy drink consumption among children and adolescents are increasing, requiring further long-term research and awareness of these issues.

• Osong Public Health and Research Perspectives
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• v.9 no.6
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• pp.299-308
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• 2018

Objectives: We aimed to examine health-related nutritional knowledge and dietary behavior related to caffeine intake among high school students (n = 310) in the Yongin region of Korea. Methods: Data were collected using a face-to-face survey, and analyzed using chi-square test, t- test, and logistic regression analysis. Results: The level of caffeine intake in respondents was divided into low (< 30 mg/d; n = 208) and high caffeine intake groups (> 30 mg/d; n = 102). Total nutritional knowledge related to bone disease was higher in the low intake group (score 2.75) than the high intake group (score 2.39; p < 0.05). The high intake group had lower scores for nutritional knowledge (score 0.70; p < 0.05) related to how caffeinated beverages affect sleep and for dietary behavior (score 3.25; p < 0.001), based on "I avoid caffeinated foods before sleep," than the low intake group (nutritional knowledge score, 0.80; dietary behavior score, 3.76). Conclusion: In the overall analysis, the low caffeine intake group had better nutritional knowledge related to bone and sleep health, and healthier dietary behavior related to sleep health compared with the high intake group.