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Sample records for caffeine markedly enhanced

  1. Caffeine Consumption, Expectancies of Caffeine-Enhanced Performance, and Caffeinism Symptoms among University Students.

    ERIC Educational Resources Information Center

    Bradley, John R.; Petree, Allen

    1990-01-01

    Gathered self-report data on college students' (n=797) expectations of caffeine-enhanced performance, level of beverage caffeine consumed daily, and caffeinism signs experienced after consumption of caffeinated beverages. Results supported extending the expectancies model of substance use motivation from alcohol to caffeine. (Author/ABL)

  2. Caffeine

    MedlinePlus

    ... mood. Caffeine is in tea, coffee, chocolate, many soft drinks, and pain relievers and other over-the-counter ... Teens usually get most of their caffeine from soft drinks and energy drinks. (In addition to caffeine, these ...

  3. Caffeine potentiates the enhancement by choline of striatal acetylcholine release

    NASA Technical Reports Server (NTRS)

    Johnson, D. A.; Ulus, I. H.; Wurtman, R. J.

    1992-01-01

    We investigated the effect of peripherally administered caffeine (50 mg/kg), choline (30, 60, or 120 mg/kg) or combinations of both drugs on the spontaneous release of acetylcholine (ACh) from the corpus striatum of anesthetized rats using in vivo microdialysis. Caffeine alone or choline in the 30 or 60 mg/kg dose failed to increase ACh in microdialysis samples; the 120 mg/kg choline dose significantly enhanced ACh during the 80 min following drug administration. Coadministration of caffeine with choline significantly increased ACh release after each of the choline doses tested. Peak microdialysate levels with the 120 mg/kg dose were increased 112% when caffeine was additionally administered, as compared with 54% without caffeine. These results indicate that choline administration can enhance spontaneous ACh release from neurons, and that caffeine, a drug known to block adenosine receptors on these neurons, can amplify the choline effect.

  4. Caffeine use by children: the quest for enhancement.

    PubMed

    Bramstedt, Katrina A

    2007-01-01

    Fair play, both in academics and sports, is a concept that is challenged by the notion of performance enhancement. Both cognitive and physical performance can be viewed as potentially enhanceable, and arguments can be made that enhancement can serve two purposes: gaining an edge or keeping up with others (who may or may not have used performance-enhancing substances). Caffeine, a central nervous system and cardiac stimulant, is frequently used by children for both academic and athletic performance enhancement. In fact, the marketplace contains a plethora of caffeinated products marketed directly to children. This article examines safety and ethical issues associated with the use of caffeine by children and explores the question: Can cognitive performance enhancement be ethically permissible if sports performance enhancement is not? PMID:17674233

  5. Caffeine

    MedlinePlus

    Caffeine is a bitter substance found in coffee, tea, soft drinks, chocolate, kola nuts, and certain medicines. It has many effects on the body's metabolism, including stimulating the central nervous system. ...

  6. Caffeine: cognitive and physical performance enhancer or psychoactive drug?

    PubMed

    Cappelletti, Simone; Piacentino, Daria; Daria, Piacentino; Sani, Gabriele; Aromatario, Mariarosaria

    2015-01-01

    Caffeine use is increasing worldwide. The underlying motivations are mainly concentration and memory enhancement and physical performance improvement. Coffee and caffeine-containing products affect the cardiovascular system, with their positive inotropic and chronotropic effects, and the central nervous system, with their locomotor activity stimulation and anxiogenic-like effects. Thus, it is of interest to examine whether these effects could be detrimental for health. Furthermore, caffeine abuse and dependence are becoming more and more common and can lead to caffeine intoxication, which puts individuals at risk for premature and unnatural death. The present review summarizes the main findings concerning caffeine's mechanisms of action (focusing on adenosine antagonism, intracellular calcium mobilization, and phosphodiesterases inhibition), use, abuse, dependence, intoxication, and lethal effects. It also suggests that the concepts of toxic and lethal doses are relative, since doses below the toxic and/or lethal range may play a causal role in intoxication or death. This could be due to caffeine's interaction with other substances or to the individuals' preexisting metabolism alterations or diseases. PMID:26074744

  7. Caffeine

    MedlinePlus

    ... a bitter substance found in coffee, tea, soft drinks, chocolate, kola nuts, and certain medicines. It has many effects on the body's metabolism, including stimulating the central nervous system. This can make you more alert and give you a boost of energy. For most people, the amount of caffeine in ...

  8. Caffeine: Cognitive and Physical Performance Enhancer or Psychoactive Drug?

    PubMed Central

    Cappelletti, Simone; Daria, Piacentino; Sani, Gabriele; Aromatario, Mariarosaria

    2015-01-01

    Caffeine use is increasing worldwide. The underlying motivations are mainly concentration and memory enhancement and physical performance improvement. Coffee and caffeine-containing products affect the cardiovascular system, with their positive inotropic and chronotropic effects, and the central nervous system, with their locomotor activity stimulation and anxiogenic-like effects. Thus, it is of interest to examine whether these effects could be detrimental for health. Furthermore, caffeine abuse and dependence are becoming more and more common and can lead to caffeine intoxication, which puts individuals at risk for premature and unnatural death. The present review summarizes the main findings concerning caffeine’s mechanisms of action (focusing on adenosine antagonism, intracellular calcium mobilization, and phosphodiesterases inhibition), use, abuse, dependence, intoxication, and lethal effects. It also suggests that the concepts of toxic and lethal doses are relative, since doses below the toxic and/or lethal range may play a causal role in intoxication or death. This could be due to caffeine’s interaction with other substances or to the individuals' preexisting metabolism alterations or diseases. PMID:26074744

  9. Acute Caffeine Consumption Enhances the Executive Control of Visual Attention in Habitual Consumers

    ERIC Educational Resources Information Center

    Brunye, Tad T.; Mahoney, Caroline R.; Lieberman, Harris R.; Giles, Grace E.; Taylor, Holly A.

    2010-01-01

    Recent work suggests that a dose of 200-400mg caffeine can enhance both vigilance and the executive control of visual attention in individuals with low caffeine consumption profiles. The present study seeks to determine whether individuals with relatively high caffeine consumption profiles would show similar advantages. To this end, we examined…

  10. Chronic caffeine treatment enhances the resilience to social defeat stress in mice.

    PubMed

    Yin, Yong-Qin; Zhang, Chun; Wang, Jian-Xin; Hou, Jia; Yang, Xu; Qin, Jing

    2015-02-01

    Strong evidence has shown that caffeine exerts antidepressant-like effects in chronic stress situations by increasing dopamine levels. However, whether caffeine mediates the dopaminergic system and interferes with the resilience to social defeat stress in mice is unknown. The aim of this study is to investigate the role of caffeine in the behavioral responses to social defeat stress and the possible regulatory role of the dopaminergic system. Mice experienced chronic social defeat stress for 10 days. Caffeine was administered intraperitoneally before, during and after social defeat stress. The time spent in interaction zone, social interaction ratio and sucrose preference test was used to measure the social avoidance and anhedonia in mice. The results showed that chronic pretreatment with caffeine for 14 days and for 10 days during stress reversed the avoidance of social behavior and anhedonia induced by social defeat stress in mice, suggesting the enhancement of the resilience to social defeat stress induced by caffeine. However, neither the treatment with caffeine only during the social defeat stress for 10 days nor the treatment with acute caffeine after defeat stress altered the resilience to stress. Furthermore, chronic caffeine treatment did not affect the normal locomotor activity and the desperate behavior in naïve mice. Moreover, the antagonism of dopamine D1 receptor and not D2 receptor reversed the effect of caffeine on the social avoidance and depressive-like behavior. Finally, pretreatment with higher doses of caffeine did not affect the behavioral response to social defeat stress. Taken together, our findings provide new insight into the effects of caffeine on social avoidance and anhedonia in mice. In addition, our results illustrated the value of measuring changes in depressive-like behavior before and after social defeat stress to determine the potential treatment of caffeine on depression through the regulation of dopaminergic system. PMID

  11. Acute stress blocks the caffeine-induced enhancement of contextual memory retrieval in mice.

    PubMed

    Pierard, Chistophe; Krazem, Ali; Henkous, Nadia; Decorte, Laurence; Béracochéa, Daniel

    2015-08-15

    This study investigated in mice the dose-effect of caffeine on memory retrieval in non-stress and stress conditions. C57 Bl/6 Jico mice learned two consecutive discriminations (D1 and D2) in a four-hole board which involved either distinct contextual (CSD) or similar contextual (SSD) cues. All mice received an i.p. injection of vehicle or caffeine (8, 16 or 32mg/kg) 30min before the test session. Results showed that in non-stress conditions, the 16mg/kg caffeine dose induced a significant enhancement of D1 performance in CSD but not in SSD. Hence, we studied the effect of an acute stress (electric footshocks) administered 15min before the test session on D1 performance in caffeine-treated mice. Results showed that stress significantly decreased D1 performance in vehicle-treated controls and the memory-enhancing effect induced by the 16mg/kg caffeine dose in non-stress condition is no longer observed. Interestingly, whereas caffeine-treated mice exhibited weaker concentrations of plasma corticosterone as compared to vehicles in non-stress condition, stress significantly increased plasma corticosterone concentrations in caffeine-treated mice which reached similar level to that of controls. Overall, the acute stress blocked both the endocrinological and memory retrieval enhancing effects of caffeine. PMID:25934571

  12. Synergistic Skin Penetration Enhancer and Nanoemulsion Formulations Promote the Human Epidermal Permeation of Caffeine and Naproxen.

    PubMed

    Abd, Eman; Namjoshi, Sarika; Mohammed, Yousuf H; Roberts, Michael S; Grice, Jeffrey E

    2016-01-01

    We examined the extent of skin permeation enhancement of the hydrophilic drug caffeine and lipophilic drug naproxen applied in nanoemulsions incorporating skin penetration enhancers. Infinite doses of fully characterized oil-in-water nanoemulsions containing the skin penetration enhancers oleic acid or eucalyptol as oil phases and caffeine (3%) or naproxen (2%) were applied to human epidermal membranes in Franz diffusion cells, along with aqueous control solutions. Caffeine and naproxen fluxes were determined over 8 h. Solute solubility in the formulations and in the stratum corneum (SC), as well as the uptake of product components into the SC were measured. The nanoemulsions significantly enhanced the skin penetration of caffeine and naproxen, compared to aqueous control solutions. Caffeine maximum flux enhancement was associated with a synergistic increase in both caffeine SC solubility and skin diffusivity, whereas a formulation-increased solubility in the SC was the dominant determinant for increased naproxen fluxes. Enhancements in SC solubility were related to the uptake of the formulation excipients containing the active compounds into the SC. Enhanced skin penetration in these systems is largely driven by uptake of formulation excipients containing the active compounds into the SC with impacts on SC solubility and diffusivity. PMID:26554868

  13. Spectroscopic study of surface enhanced Raman scattering of caffeine on borohydride-reduced silver colloids

    NASA Astrophysics Data System (ADS)

    Chen, Xiaomin; Gu, Huaimin; Shen, Gaoshan; Dong, Xiao; Kang, Jian

    2010-06-01

    The surface enhanced Raman scattering (SERS) of caffeine on borohydride-reduced silver colloids system under different aqueous solution environment has been studied in this paper. The relative intensity of SERS of caffeine significantly varies with different concentrations of sodium chloride and silver particles. However, at too high or too low concentration of sodium chloride and silver particle, the enhancement of SERS spectra is not evident. The SERS spectra of caffeine suggest that the contribution of the charge transfer mechanism to SERS may be dominant. The chloride ions can significantly enhance the efficiency of SERS, while the enhancement is selective, as the efficiency in charge transfer enhancement is higher than in electromagnetic enhancement. Therefore, it can be concluded that the active site of chloride ion locates on the bond between the caffeine and the silver surface. In addition, the SERS spectra of caffeine on borohydride-reduced and citrate-reduced silver colloids are different, which may be due to different states caffeine adsorbed on silver surface under different silver colloids.

  14. Action of caffeine on x-irradiated HeLa cells. VII. Evidence that caffeine enhances expression of potentially lethal radiation damage

    SciTech Connect

    Beetham, K.L.; Tolmach, L.J.

    1984-12-01

    HeLa cells irradiated with 2 Gy of 220-kV X rays suffer a 60-70% loss of colony-forming ability which is increased to 90% by postirradiation treatment with 10 mM caffeine for 6 hr. The detailed postirradiation patterns of cell death and sister-cell fusion in such cultures and in cultures in which the colony-forming ability was brought to about the same level by treatment with a larger (4 Gy) X-ray dose alone or by longer (48 hr) treatment with 10 mM caffeine alone were recorded by time-lapse cinemicrography. Because the patterns of cell death and fusion differ radically in irradiated and in caffeine-treated cultures, the response of the additional cells killed by the combined treatment can be identified as X-ray induced rather than caffeine induced. The appearance of cultures after several days of incubation confirms the similarity of the post-treatment patterns of proliferation in cultures suffering enhanced killing to those occurring in cultures treated with larger doses of X rays alone. It is concluded that x rays do not sensitize cells to caffeine, but rather that caffeine enhanced the expression of potentially lethal radiation-induced damage.

  15. What Users Think about the Differences between Caffeine and Illicit/Prescription Stimulants for Cognitive Enhancement

    PubMed Central

    Franke, Andreas G.

    2012-01-01

    Pharmacological cognitive enhancement (CE) is a topic of increasing public awareness. In the scientific literature on student use of CE as a study aid for academic performance enhancement, there are high prevalence rates regarding the use of caffeinated substances (coffee, caffeinated drinks, caffeine tablets) but remarkably lower prevalence rates regarding the use of illicit/prescription stimulants such as amphetamines or methylphenidate. While the literature considers the reasons and mechanisms for these different prevalence rates from a theoretical standpoint, it lacks empirical data to account for healthy students who use both, caffeine and illicit/prescription stimulants, exclusively for the purpose of CE. Therefore, we extensively interviewed a sample of 18 healthy university students reporting non-medical use of caffeine as well as illicit/prescription stimulants for the purpose of CE in a face-to-face setting about their opinions regarding differences in general and morally-relevant differences between caffeine and stimulant use for CE. 44% of all participants answered that there is a general difference between the use of caffeine and illicit/prescription stimulants for CE, 28% did not differentiate, 28% could not decide. Furthermore, 39% stated that there is a moral difference, 56% answered that there is no moral difference and one participant was not able to comment on moral aspects. Participants came to their judgements by applying three dimensions: medical, ethical and legal. Weighing the medical, ethical and legal aspects corresponded to the students' individual preferences of substances used for CE. However, their views only partly depicted evidence-based medical aspects and the ethical issues involved. This result shows the need for well-directed and differentiated information to prevent the potentially harmful use of illicit or prescription stimulants for CE. PMID:22768218

  16. Removal of caffeine from green tea by microwave-enhanced vacuum ice water extraction.

    PubMed

    Lou, Zaixiang; Er, Chaojuan; Li, Jing; Wang, Hongxin; Zhu, Song; Sun, Juntao

    2012-02-24

    In order to selectively remove caffeine from green tea, a microwave-enhanced vacuum ice water extraction (MVIE) method was proposed. The effects of MVIE variables including extraction time, microwave power, and solvent to solid radio on the removal yield of caffeine and the loss of total phenolics (TP) from green tea were investigated. The optimized conditions were as follows: solvent (mL) to solid (g) ratio was 10:1, microwave extraction time was 6 min, microwave power was 350 W and 2.5 h of vacuum ice water extraction. The removal yield of caffeine by MVIE was 87.6%, which was significantly higher than that by hot water extraction, indicating a significant improvement of removal efficiency. Moreover, the loss of TP of green tea in the proposed method was much lower than that in the hot water extraction. After decaffeination by MVIE, the removal yield of TP tea was 36.2%, and the content of TP in green tea was still higher than 170 mg g(-1). Therefore, the proposed microwave-enhanced vacuum ice water extraction was selective, more efficient for the removal of caffeine. The main phenolic compounds of green tea were also determined, and the results indicated that the contents of several catechins were almost not changed in MVIE. This study suggests that MVIE is a new and good alternative for the removal of caffeine from green tea, with a great potential for industrial application. PMID:22284877

  17. Caffeine-enhanced survival of radiation-sensitive, repair-deficient Chinese hamster cells

    SciTech Connect

    Utsumi, H.; Elkind, M.M.

    1983-11-01

    A clone of V79 Chinese hamster cells (V79-AL162/S-10) with unique properties has been isolated after a challenge of parental cells (V79-AL162) with 1 mM ouabain. Compared with parental cells, or with other clones isolated after the ouabain challenge, these cells form smaller colonies, are more sensitive to both x rays and fission-spectrum neutrons, and respond atypically to a postirradiation treatment with caffeine. Their enhanced response to x rays results mainly from a large reduction in the shoulder of their survival curve, probably because in late S phase, the most resistant phase in the cell cycle, the survival curve of these cells has a reduced shoulder width. Caffeine, and to a lesser extent theophylline, added to the colony-forming medium immediately after exposure appreciably increases the width of the shoulder of these sensitive cells, whereas caffeine has the opposite effect on the response of normal V79 cells. Thus the unique response of the V79-AL162/S-10 cells to a radiation posttreatment with caffeine (increased survival) results from a net increase in their ability to repair damage that is otherwise lethal; caffeine treatment ordinarly prevents normal V79 cells from repairing damage that is only potentially lethal.

  18. Extraction and removal of caffeine from green tea by ultrasonic-enhanced supercritical fluid.

    PubMed

    Tang, Wei-Qiang; Li, Di-Cai; Lv, Yang-Xiao; Jiang, Jian-Guo

    2010-05-01

    Low-caffeine or caffeine-removed tea and its products are widely welcomed on market in recent years. In the present study, we adopt ultrasonic-enhanced supercritical fluid extraction process to remove caffeine from green tea. An orthogonal experiment (L16 (4(5))) was applied to optimize the best removal conditions. Extraction pressure, extraction time, power of ultrasound, moisture content, and temperature were the main factors to influence the removal rate of caffeine from green tea. The 5 factors chosen for the present investigation were based on the results of a single-factor test. The optimum removal conditions were determined as follows: extraction pressure of 30 MPa, temperature at 55 degrees C, time of 4 h, 30% moisture content, and ultrasound power of 100 W. Chromatogram and ultraviolet analysis of raw material and decaffeinates suggests that under optimized conditions, the caffeine of green tea was effectively removed and minished without damaging the structure of active ingredients in green tea. PMID:20546396

  19. Enhancing physical performance in elite junior tennis players with a caffeinated energy drink.

    PubMed

    Gallo-Salazar, César; Areces, Francisco; Abián-Vicén, Javier; Lara, Beatriz; Salinero, Juan José; Gonzalez-Millán, Cristina; Portillo, Javier; Muñoz, Victor; Juarez, Daniel; Del Coso, Juan

    2015-04-01

    The aim of this study was to investigate the effectiveness of a caffeinated energy drink to enhance physical performance in elite junior tennis players. In 2 different sessions separated by 1 wk, 14 young (16 ± 1 y) elite-level tennis players ingested 3 mg caffeine per kg body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed a handgrip-strength test, a maximal-velocity serving test, and an 8 × 15-m sprint test and then played a simulated singles match (best of 3 sets). Instantaneous running speed during the matches was assessed using global positioning (GPS) devices. Furthermore, the matches were videotaped and notated afterward. In comparison with the placebo drink, the ingestion of the caffeinated energy drink increased handgrip force by ~4.2% ± 7.2% (P = .03) in both hands, the running pace at high intensity (46.7 ± 28.5 vs 63.3 ± 27.7 m/h, P = .02), and the number of sprints (12.1 ± 1.7 vs 13.2 ± 1.7, P = .05) during the simulated match. There was a tendency for increased maximal running velocity during the sprint test (22.3 ± 2.0 vs 22.9 ± 2.1 km/h, P = .07) and higher percentage of points won on service with the caffeinated energy drink (49.7% ± 9.8% vs 56.4% ± 10.0%, P = .07) in comparison with the placebo drink. The energy drink did not improve ball velocity during the serving test (42.6 ± 4.8 vs 42.7 ± 5.0 m/s, P = .49). The preexercise ingestion of caffeinated energy drinks was effective to enhance some aspects of physical performance of elite junior tennis players. PMID:25158287

  20. Caffeine ingestion enhances perceptual responses during intermittent exercise in female team-game players.

    PubMed

    Ali, Ajmol; O'Donnell, Jemma; Von Hurst, Pamela; Foskett, Andrew; Holland, Sherina; Starck, Carlene; Rutherfurd-Markwick, Kay

    2016-01-01

    We examined the influence of caffeine supplementation on cognitive performance and perceptual responses in female team-game players taking low-dose monophasic oral contraceptives of the same hormonal composition. Ten females (24 ± 4 years; 59.7 ± 3.5 kg body mass; 2-6 training sessions per week) took part in a randomised, double-blind, placebo-controlled crossover-design trial. A 90-min intermittent treadmill-running protocol was completed 60 min following ingestion of a capsule containing either 6 mg • kg(-1) anhydrous caffeine or artificial sweetener (placebo). Perceptual responses (ratings of perceived exertion (RPE), feeling scale (FS), felt arousal scale (FAS)), mood (profile of mood states (POMS)) and cognitive performance (Stroop test, choice reaction time (CRT)) were completed before, during and after the exercise protocol, as well as after ~12 h post exercise. Caffeine ingestion significantly enhanced the ratings of pleasure (P = 0.008) and arousal (P = 0.002) during the exercise protocol, as well as increased vigour (POMS; P = 0.007), while there was a tendency for reduced fatigue (POMS; P = 0.068). Caffeine ingestion showed a tendency to decrease RPE (P = 0.068) and improve reaction times in the Stroop (P = 0.072) and CRT (P = 0.087) tests. Caffeine supplementation showed a positive effect on perceptual parameters by increasing vigour and a tendency to decrease fatigue during intermittent running activity in female games players taking low-dose monophasic oral contraceptive steroids (OCS). PMID:26045170

  1. Caffeine Use and Extroversion.

    ERIC Educational Resources Information Center

    Landrum, R. Eric; Meliska, Charles J.

    Some research on the stimulant effect of caffeine suggests that the amount of behavioral enhancement produced by caffeine may depend on subjects' prior experience with the task and the drug. A study was undertaken to test whether prior experience with a task while under the influence of caffeine would facilitate performance of that task. Male…

  2. Caffeinated Energy Drinks -- A Growing Problem

    PubMed Central

    Reissig, Chad J.; Strain, Eric C.; Griffiths, Roland R.

    2009-01-01

    Since the introduction of Red Bull in Austria in 1987 and in the United States in 1997, the energy drink market has grown exponentially. Hundreds of different brands are now marketed, with caffeine content ranging from a modest 50 mg to an alarming 505 mg per can or bottle. Regulation of energy drinks, including content labeling and health warnings differs across countries, with some of the most lax regulatory requirements in the U.S. The absence of regulatory oversight has resulted in aggressive marketing of energy drinks, targeted primarily toward young males, for psychoactive, performance-enhancing and stimulant drug effects. There are increasing reports of caffeine intoxication from energy drinks, and it seems likely that problems with caffeine dependence and withdrawal will also increase. In children and adolescents who are not habitual caffeine users, vulnerability to caffeine intoxication may be markedly increased due to an absence of pharmacological tolerance. Genetic factors may also contribute to an individual’s vulnerability to caffeine related disorders including caffeine intoxication, dependence, and withdrawal. The combined use of caffeine and alcohol is increasing sharply, and studies suggest that such combined use may increase the rate of alcohol-related injury. Several studies suggest that energy drinks may serve as a gateway to other forms of drug dependence. Regulatory implications concerning labeling and advertising, and the clinical implications for children and adolescents are discussed. PMID:18809264

  3. Action of caffeine on x-irradiated HeLa cells. IV. Progression delays and enhanced cell killing at high caffeine concentrations

    SciTech Connect

    Tolmach, L.J.; Busse, P.M.

    1980-05-01

    The response of x-irradiated and unirradiated HeLa S3 cells to treatment with caffeine at concentrations between 1 and 10 nM has been examined with respect to both delay in progression through the cell generation cycle and enhancement of the expression of potentially lethal x-ray damage. Progression is delayed in a concentration-dependent fashion: the generation time is doubled at about 4 mM. The duration of G/sub 1/ is lengthened, and the rate of DNA synthesis is reduced, although the kinetics are different in the two phases; the rate of DNA synthesis is usually unaffected at 1 or 2 mM, while there is no concentration threshold for the slowing of progression through G/sub 1/. Progression through G/sub 2/ appears to be unaffected by concentrations up to at least 10 mM. Killing of irradiated cells in G/sub 2/ is somewhat greater after treatment with the higher caffeine concentrations than reported previously for 1 mM. Moreover, an additional mode of killing is observed in irradiated G/sub 1/ cells which had been found previously to be only slightly affected by 1 mM caffeine; they suffer extensive killing at concentrations above 5 mM. The time-survival curves for irradiated, caffeine-treated G/sub 1/ and G/sub 2/ cells have characteristically different shapes. The dose-survival curves for cells treated with the higher caffeine concentrations display steeper terminal slopes and narrower shoulders.

  4. Caffeine and exercise.

    PubMed

    Paluska, Scott A

    2003-08-01

    Caffeine is the most commonly consumed drug in the world, and athletes frequently use it as an ergogenic aid. It improves performance and endurance during prolonged, exhaustive exercise. To a lesser degree it also enhances short-term, high-intensity athletic performance. Caffeine improves concentration, reduces fatigue, and enhances alertness. Habitual intake does not diminish caffeine's ergogenic properties. Several mechanisms have been proposed to explain the physiologic effects of caffeine, but adenosine receptor antagonism most likely accounts for the primary mode of action. It is relatively safe and has no known negative performance effects, nor does it cause significant dehydration or electrolyte imbalance during exercise. Routine caffeine consumption may cause tolerance or dependence, and abrupt discontinuation produces irritability, mood shifts, headache, drowsiness, or fatigue. Major sport governing bodies ban excessive use of caffeine, but current monitoring techniques are inadequate, and ethical dilemmas persist regarding caffeine intake by athletes. PMID:12834577

  5. Make caffeine visible: a fluorescent caffeine "traffic light" detector.

    PubMed

    Xu, Wang; Kim, Tae-Hyeong; Zhai, Duanting; Er, Jun Cheng; Zhang, Liyun; Kale, Anup Atul; Agrawalla, Bikram Keshari; Cho, Yoon-Kyoung; Chang, Young-Tae

    2013-01-01

    Caffeine has attracted abundant attention due to its extensive existence in beverages and medicines. However, to detect it sensitively and conveniently remains a challenge, especially in resource-limited regions. Here we report a novel aqueous phase fluorescent caffeine sensor named Caffeine Orange which exhibits 250-fold fluorescence enhancement upon caffeine activation and high selectivity. Nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy indicate that π-stacking and hydrogen-bonding contribute to their interactions while dynamic light scattering and transmission electron microscopy experiments demonstrate the change of Caffeine Orange ambient environment induces its fluorescence emission. To utilize this probe in real life, we developed a non-toxic caffeine detection kit and tested it for caffeine quantification in various beverages. Naked-eye sensing of various caffeine concentrations was possible based on color changes upon irradiation with a laser pointer. Lastly, we performed the whole system on a microfluidic device to make caffeine detection quick, sensitive and automated. PMID:23877095

  6. Investigation of the binding sites and orientation of caffeine on human serum albumin by surface-enhanced Raman scattering and molecular docking

    NASA Astrophysics Data System (ADS)

    Wang, Weinan; Zhang, Wei; Duan, Yaokai; Jiang, Yong; Zhang, Liangren; Zhao, Bing; Tu, Pengfei

    2013-11-01

    Fluorescence, normal Raman and surface-enhanced Raman scattering (SERS) were introduced to explore the absorptive geometry of caffeine on Human Serum Albumin (HSA) at physiological condition. The molecular docking was also employed to make a better understanding of the interaction between caffeine and HSA as well as to elucidate the detailed information of the major binding site. The results showed that caffeine could bind to HSA via the hydrophobic force of aromatic stacking and the main binding group on caffeine could be the pyrimidine ring. In addition, a consecutive set of changes in the orientation of caffeine molecule had been demonstrated during the process of caffeine binding to HSA, and the primary binding site was considered to be a hydrophobic cavity formed by Leu198, Lys199, Ser202, Phe211, Trp214, Val344, Ser454 and Leu481 in domain II.

  7. Caffeine Enhances Real-World Language Processing: Evidence from a Proofreading Task

    ERIC Educational Resources Information Center

    Brunye, Tad T.; Mahoney, Caroline R.; Rapp, David N.; Ditman, Tali; Taylor, Holly A.

    2012-01-01

    Caffeine has become the most prevalently consumed psychostimulant in the world, but its influences on daily real-world functioning are relatively unknown. The present work investigated the effects of caffeine (0 mg, 100 mg, 200 mg, 400 mg) on a commonplace language task that required readers to identify and correct 4 error types in extended…

  8. Using Caffeine Pills for Performance Enhancement. An Experimental Study on University Students’ Willingness and Their Intention to Try Neuroenhancements

    PubMed Central

    Brand, Ralf; Koch, Helen

    2016-01-01

    Recent research has indicated that university students sometimes use caffeine pills for neuroenhancement (NE; non-medical use of psychoactive substances or technology to produce a subjective enhancement in psychological functioning and experience), especially during exam preparation. In our factorial survey experiment, we manipulated the evidence participants were given about the prevalence of NE amongst peers and measured the resulting effects on the psychological predictors included in the Prototype-Willingness Model of risk behavior. Two hundred and thirty-one university students were randomized to a high prevalence condition (read faked research results overstating usage of caffeine pills amongst peers by a factor of 5; 50%), low prevalence condition (half the estimated prevalence; 5%) or control condition (no information about peer prevalence). Structural equation modeling confirmed that our participants’ willingness and intention to use caffeine pills in the next exam period could be explained by their past use of neuroenhancers, attitude to NE and subjective norm about use of caffeine pills whilst image of the typical user was a much less important factor. Provision of inaccurate information about prevalence reduced the predictive power of attitude with respect to willingness by 40-45%. This may be because receiving information about peer prevalence which does not fit with their perception of the social norm causes people to question their attitude. Prevalence information might exert a deterrent effect on NE via the attitude-willingness association. We argue that research into NE and deterrence of associated risk behaviors should be informed by psychological theory. PMID:26903909

  9. Using Caffeine Pills for Performance Enhancement. An Experimental Study on University Students' Willingness and Their Intention to Try Neuroenhancements.

    PubMed

    Brand, Ralf; Koch, Helen

    2016-01-01

    Recent research has indicated that university students sometimes use caffeine pills for neuroenhancement (NE; non-medical use of psychoactive substances or technology to produce a subjective enhancement in psychological functioning and experience), especially during exam preparation. In our factorial survey experiment, we manipulated the evidence participants were given about the prevalence of NE amongst peers and measured the resulting effects on the psychological predictors included in the Prototype-Willingness Model of risk behavior. Two hundred and thirty-one university students were randomized to a high prevalence condition (read faked research results overstating usage of caffeine pills amongst peers by a factor of 5; 50%), low prevalence condition (half the estimated prevalence; 5%) or control condition (no information about peer prevalence). Structural equation modeling confirmed that our participants' willingness and intention to use caffeine pills in the next exam period could be explained by their past use of neuroenhancers, attitude to NE and subjective norm about use of caffeine pills whilst image of the typical user was a much less important factor. Provision of inaccurate information about prevalence reduced the predictive power of attitude with respect to willingness by 40-45%. This may be because receiving information about peer prevalence which does not fit with their perception of the social norm causes people to question their attitude. Prevalence information might exert a deterrent effect on NE via the attitude-willingness association. We argue that research into NE and deterrence of associated risk behaviors should be informed by psychological theory. PMID:26903909

  10. Caffeine and Your Child

    MedlinePlus

    ... National Soft Drink Association previous continue What's Caffeine Sensitivity? Caffeine sensitivity refers to the amount of caffeine that will ... caffeine necessary to produce side effects. However, caffeine sensitivity is most affected by daily caffeine intake. People ...

  11. A Combination of Amino Acids and Caffeine Enhances Sprint Running Capacity in a Hot, Hypoxic Environment.

    PubMed

    Eaton, Tom R; Potter, Aaron; Billaut, François; Panchuk, Derek; Pyne, David B; Gore, Christopher J; Chen, Ting-Ting; McQuade, Leon; Stepto, Nigel K

    2016-02-01

    Heat and hypoxia exacerbate central nervous system (CNS) fatigue. We therefore investigated whether essential amino acid (EAA) and caffeine ingestion attenuates CNS fatigue in a simulated team sport-specific running protocol in a hot, hypoxic environment. Subelite male team sport athletes (n = 8) performed a repeat sprint running protocol on a nonmotorized treadmill in an extreme environment on 4 separate occasions. Participants ingested one of four supplements: a double placebo, 3 mg.kg-1 body mass of caffeine + placebo, 2 x 7 g EAA (Musashi Create)+placebo, or caffeine + EAA before each exercise session using a randomized, double-blind crossover design. Electromyography (EMG) activity and quadriceps evoked responses to magnetic stimulation were assessed from the dominant leg at preexercise, halftime, and postexercise. Central activation ratio (CAR) was used to quantify completeness of quadriceps activation. Oxygenation of the prefrontal cortex was measured via near-infrared spectroscopy. Mean sprint work was higher (M = 174 J, 95% CI [23, 324], p < .05, d = 0.30; effect size, likely beneficial) in the caffeine + EAA condition versus EAAs alone. The decline in EMG activity was less (M = 13%, 95% CI [0, 26]; p < .01, d = 0.58, likely beneficial) in caffeine + EAA versus EAA alone. Similarly, the pre- to postexercise decrement in CAR was significantly less (M = -2.7%, 95% CI [0.4, 5.4]; p < .05, d = 0.50, likely beneficial) when caffeine + EAA were ingested compared with placebo. Cerebral oxygenation was lower (M = -5.6%, 95% CI [1.0, 10.1]; p < .01, d = 0.60, very likely beneficial) in the caffeine + EAA condition compared with LNAA alone. Co-ingestion of caffeine and EAA appears to maintain muscle activation and central drive, with a small improvement in running performance. PMID:26248498

  12. Caffeine overdose

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002579.htm Caffeine overdose To use the sharing features on this page, please enable JavaScript. Caffeine is a substance that exists naturally in certain ...

  13. Caffeine overdose

    MedlinePlus

    Caffeine is a substance that exists naturally in certain plants. It can also be man-made and ... is a diuretic, which means it increases urination. Caffeine overdose occurs when someone takes in more than ...

  14. Acute consumption of a caffeinated energy drink enhances aspects of performance in sprint swimmers.

    PubMed

    Lara, Beatriz; Ruiz-Vicente, Diana; Areces, Francisco; Abián-Vicén, Javier; Salinero, Juan José; Gonzalez-Millán, Cristina; Gallo-Salazar, César; Del Coso, Juan

    2015-09-28

    This study investigated the effect of a caffeinated energy drink on various aspects of performance in sprint swimmers. In a randomised and counterbalanced order, fourteen male sprint swimmers performed two acute experimental trials after the ingestion of a caffeinated energy drink (3 mg/kg) or after the ingestion of the same energy drink without caffeine (0 mg/kg; placebo). After 60 min of ingestion of the beverages, the swimmers performed a countermovement jump, a maximal handgrip test, a 50 m simulated competition and a 45 s swim at maximal intensity in a swim ergometer. A blood sample was withdrawn 1 min after the completion of the ergometer test. In comparison with the placebo drink, the intake of the caffeinated energy drink increased the height in the countermovement jump (49.4 (SD 5.3) v. 50.9 (SD 5.2) cm, respectively; P<0.05) and maximal force during the handgrip test with the right hand (481 (SD 49) v. 498 (SD 43) N; P<0.05). Furthermore, the caffeinated energy drink reduced the time needed to complete the 50 m simulated swimming competition (27.8 (SD 3.4) v. 27.5 (SD 3.2) s; P<0.05), and it increased peak power (273 (SD 55) v. 303 (SD 49) W; P <0.05) and blood lactate concentration (11.0 (SD 2.0) v. 11.7 (SD 2.1) mM; P<0.05) during the ergometer test. The caffeinated energy drink did not modify the prevalence of insomnia (7 v. 7%), muscle pain (36 v. 36%) or headache (0 v. 7%) during the hours following its ingestion (P>0.05). A caffeinated energy drink increased some aspects of swimming performance in competitive sprinters, whereas the side effects derived from the intake of this beverage were marginal at this dosage. PMID:26279580

  15. Caffeine enhances astroglia and microglia reactivity induced by 3,4-methylenedioxymethamphetamine ('ecstasy') in mouse brain.

    PubMed

    Khairnar, Amit; Plumitallo, Antonio; Frau, Lucia; Schintu, Nicoletta; Morelli, Micaela

    2010-05-01

    Several reports suggest that 3,4-methylenedioxymethamphetamine (MDMA) induces neurotoxic effects and gliosis. Since recreational use of MDMA is often associated with caffeinated beverages, we investigated whether caffeine interferes with MDMA-induced astroglia and microglia activation, thus facilitating its neurotoxicity. MDMA (4 x 20 mg/kg) was acutely administered to mice alone or in combination with caffeine (10 mg/kg). CD11b and GFAP immunoreactivity were evaluated as markers of microglia and astroglia activation in the substantia nigra pars-compacta (SNc) and striatum. MDMA was associated with significantly higher CD11b and GFAP immunoreactivity in striatum, whereas only CD11b was significantly higher than vehicle in SNc. Caffeine potentiated the increase in CD11b and GFAP in the striatum but not in the SNc of MDMA-treated mice. The abuse of MDMA is a growing worldwide problem; the results of this study suggest that combination of MDMA plus caffeine by increasing glial activation might have harmful health consequences. PMID:19882200

  16. Enhanced killing effects of caffein post-treatment in ultraviolet-light irradiated mouse lymphoma cells: is cAMP a mediator of the effects?

    PubMed

    Kuwashima, Y; Miyachi, Y; Okada, S; Iio, M; Nakamura, N

    1983-01-01

    Effects of post-treatment with caffein, cyclic adenosine 3':5'-monophosphate (cAMP) and N6, O2-dibutyryl cAMP (dbcAMP) were investigated in ultraviolet light (UV)-irradiated mouse lymphoma L5178Y cells. Under conditions where UV or each chemical alone caused only slight cytotoxic effects, caffein post-treatment showed clear synergistic effects in cell killing but not for cAMP or dbcAMP. Subsequently, a mutant clone resistant to cAMP was isolated. This mutant was supposed to be deficient in cAMP-mediated cellular functions. Using the mutant cells, it was found that these cells were also sensitive to caffein post-treatment as wild cells after UV-irradiation. The results imply that the enhanced killing effects by caffein post-treatment in UV irradiated cells is not mediated by cAMP. PMID:6093199

  17. Caffeine content of brewed teas.

    PubMed

    Chin, Jenna M; Merves, Michele L; Goldberger, Bruce A; Sampson-Cone, Angela; Cone, Edward J

    2008-10-01

    Caffeine is the world's most popular drug and can be found in many beverages including tea. It is a psychostimulant that is widely used to enhance alertness and improve performance. This study was conducted to determine the concentration of caffeine in 20 assorted commercial tea products. The teas were brewed under a variety of conditions including different serving sizes and steep-times. Caffeine was isolated from the teas with liquid-liquid extraction and quantitated by gas chromatography with nitrogen-phosphorus detection. Caffeine concentrations in white, green, and black teas ranged from 14 to 61 mg per serving (6 or 8 oz) with no observable trend in caffeine concentration due to the variety of tea. The decaffeinated teas contained less than 12 mg of caffeine per serving, and caffeine was not detected in the herbal tea varieties. In most instances, the 6- and 8-oz serving sizes contained similar caffeine concentrations per ounce, but the steep-time affected the caffeine concentration of the tea. These findings indicate that most brewed teas contain less caffeine per serving than brewed coffee. PMID:19007524

  18. Caffeine addiction? Caffeine for youth? Time to act!

    PubMed

    Budney, Alan J; Emond, Jennifer A

    2014-11-01

    While data accumulate and discussion evolves on the clinical importance of caffeine addiction and its classification, the growing practices of (i) adding increasing amounts of caffeine to drinks and other consumables, (ii) promoting these as performance enhancers and (iii) targeting youth as the consumer raise concerns that require immediate action. PMID:24984891

  19. Development and characterization of polyphenon 60 and caffeine microemulsion for enhanced antibacterial activity.

    PubMed

    Gupta, Sonal; Bansal, Rakhi; Ali, Javed; Gabrani, Reema; Dang, Shweta

    2014-01-01

    Green tea catechins and caffeine have exhibited antibacterial activity; however, their use is limited by lack of stability and effective delivery systems. Polyphenon 60 (P60) and caffeine were encapsulated in a single microemulsion (ME) formulation with an objective to lower the minimum inhibitory concentrations (MICs) of the individual agents against selected pathogens (S. epidermidis and E. coli). Combination of two natural compounds would advocate two different mechanisms on the bacterial growth thereby providing for better antibacterial activity. Thermodynamically stable ME was developed and characterized with an average particle size of 17.58 nm, further confirmed by TEM analysis. Antibacterial studies included chequerboard microdilution assay to determine the MIC and fractional inhibitory concentration (FIC) of both the natural compounds individually and in combination. MIC and FIC results indicated that the combination of the above two natural compounds was proficient in lowering the MICs of individual agents. Results of DPPH assay indicated that ME system preserved the long term antioxidative potential of P60 and caffeine. The cytotoxicity of the optimized formulation on Vero cell line by MTT assay was found to be nontoxic to mammalian cells. PMID:25050379

  20. Development and Characterization of Polyphenon 60 and Caffeine Microemulsion for Enhanced Antibacterial Activity

    PubMed Central

    Gupta, Sonal; Bansal, Rakhi; Ali, Javed; Gabrani, Reema; Dang, Shweta

    2014-01-01

    Green tea catechins and caffeine have exhibited antibacterial activity; however, their use is limited by lack of stability and effective delivery systems. Polyphenon 60 (P60) and caffeine were encapsulated in a single microemulsion (ME) formulation with an objective to lower the minimum inhibitory concentrations (MICs) of the individual agents against selected pathogens (S. epidermidis and E. coli). Combination of two natural compounds would advocate two different mechanisms on the bacterial growth thereby providing for better antibacterial activity. Thermodynamically stable ME was developed and characterized with an average particle size of 17.58 nm, further confirmed by TEM analysis. Antibacterial studies included chequerboard microdilution assay to determine the MIC and fractional inhibitory concentration (FIC) of both the natural compounds individually and in combination. MIC and FIC results indicated that the combination of the above two natural compounds was proficient in lowering the MICs of individual agents. Results of DPPH assay indicated that ME system preserved the long term antioxidative potential of P60 and caffeine. The cytotoxicity of the optimized formulation on Vero cell line by MTT assay was found to be nontoxic to mammalian cells. PMID:25050379

  1. Caffeine enhanced measurement of mutagenesis by low levels of [gamma]-irradiation in human lymphocytes

    SciTech Connect

    Puck, T.P.; Johnson, R.; Waldren, C.A. ); Morse, H. )

    1993-09-01

    The well-known action of caffeine in synergizing mutagenesis (including chromosome aberrations) of agents like ionizing radiation by inhibition of cellular repair processes has been incorporated into a rapid procedure for detection of mutagenicity with high sensitivity. Effects of 5-10 rads of [gamma]-irradiation, which approximate the human lifetime dose accumulation from background radiation, can be detected in a two-day procedure using an immortalized human WBC culture. Chromosomally visible lesions are scored on cells incubated for 2 h after irradiation in the presence and absence of 1.0 mg/ml of caffeine. An eightfold amplification of scorable lesions is achieved over the action of radiation alone. This approach provides a closer approximation to absolute mutagenicity unmitigated by repair processes, which can vary in different situations. It is proposed that mutagenesis testing of this kind, using caffiene or other repair-inhibitory agents, be employed to identify mutagens in their effective concentrations to which human populations may be exposed; to detect agents such as caffeine that may synergize mutagenic actions and pose epidemiologic threats; and to discover effective anti-mutagens. Information derived from the use of such procedures may help prevent cancer and newly acquired genetic disease.

  2. Caffeine renal clearance and urine caffeine concentrations during steady state dosing. Implications for monitoring caffeine intake during sports events.

    PubMed Central

    Birkett, D J; Miners, J O

    1991-01-01

    1. Relationships between the plasma and urine concentrations and clearances of caffeine over successive dosage intervals at steady-state were investigated in six healthy volunteers administered caffeine, 150 mg 8 hourly for 6 days. 2. There was marked inter-individual variability in the urine (15.9-fold range) and steady-state plasma (8.1-fold range) concentrations of caffeine. 3. Urine caffeine concentrations were similar to those in plasma, with mean ratios (plasma:urine) ranging from 1.10 to 1.74. There was a good correlation (r = 0.93, P less than 0.01) between caffeine urine and plasma concentrations. 4. There was a good correlation between caffeine renal clearance and urine flow rate (r = 0.89, P less than 0.01). Caffeine renal clearance was not significantly different from the product of fu and urine flow rate, where fu is the fraction of caffeine unbound in plasma. Urine caffeine concentration and urine flow rate were not correlated (r = 0.14, P greater than 0.05). 5. The results indicate that caffeine is reabsorbed from the renal tubule to equilibrium with unbound caffeine in plasma. 6. A regulatory urine caffeine concentration limit of 12 mg 1(-1) may be exceeded by some individuals with coffee intake in the range 3 to 6 cups per day. PMID:2049248

  3. Caffeine consumption.

    PubMed

    Barone, J J; Roberts, H R

    1996-01-01

    Scientific literature cites a wide range of values for caffeine content in food products. The authors suggest the following standard values for the United States: coffee (5 oz) 85 mg for ground roasted coffee, 60 mg for instant and 3 mg for decaffeinated; tea (5 oz): 30 mg for leaf/bag and 20 mg for instant; colas: 18 mg/6 oz serving; cocoa/hot chocolate: 4 mg/5 oz; chocolate milk: 4 mg/6 oz; chocolate candy: 1.5-6.0 mg/oz. Some products from the United Kingdom and Denmark have higher caffeine content. Caffeine consumption survey data are limited. Based on product usage and available consumption data, the authors suggest a mean daily caffeine intake for US consumers of 4 mg/kg. Among children younger than 18 years of age who are consumers of caffeine-containing foods, the mean daily caffeine intake is about 1 mg/kg. Both adults and children in Denmark and UK have higher levels of caffeine intake. PMID:8603790

  4. Make Caffeine Visible: a Fluorescent Caffeine “Traffic Light” Detector

    NASA Astrophysics Data System (ADS)

    Xu, Wang; Kim, Tae-Hyeong; Zhai, Duanting; Er, Jun Cheng; Zhang, Liyun; Kale, Anup Atul; Agrawalla, Bikram Keshari; Cho, Yoon-Kyoung; Chang, Young-Tae

    2013-07-01

    Caffeine has attracted abundant attention due to its extensive existence in beverages and medicines. However, to detect it sensitively and conveniently remains a challenge, especially in resource-limited regions. Here we report a novel aqueous phase fluorescent caffeine sensor named Caffeine Orange which exhibits 250-fold fluorescence enhancement upon caffeine activation and high selectivity. Nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy indicate that π-stacking and hydrogen-bonding contribute to their interactions while dynamic light scattering and transmission electron microscopy experiments demonstrate the change of Caffeine Orange ambient environment induces its fluorescence emission. To utilize this probe in real life, we developed a non-toxic caffeine detection kit and tested it for caffeine quantification in various beverages. Naked-eye sensing of various caffeine concentrations was possible based on color changes upon irradiation with a laser pointer. Lastly, we performed the whole system on a microfluidic device to make caffeine detection quick, sensitive and automated.

  5. Make Caffeine Visible: a Fluorescent Caffeine “Traffic Light” Detector

    PubMed Central

    Xu, Wang; Kim, Tae-Hyeong; Zhai, Duanting; Er, Jun Cheng; Zhang, Liyun; Kale, Anup Atul; Agrawalla, Bikram Keshari; Cho, Yoon-Kyoung; Chang, Young-Tae

    2013-01-01

    Caffeine has attracted abundant attention due to its extensive existence in beverages and medicines. However, to detect it sensitively and conveniently remains a challenge, especially in resource-limited regions. Here we report a novel aqueous phase fluorescent caffeine sensor named Caffeine Orange which exhibits 250-fold fluorescence enhancement upon caffeine activation and high selectivity. Nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy indicate that π-stacking and hydrogen-bonding contribute to their interactions while dynamic light scattering and transmission electron microscopy experiments demonstrate the change of Caffeine Orange ambient environment induces its fluorescence emission. To utilize this probe in real life, we developed a non-toxic caffeine detection kit and tested it for caffeine quantification in various beverages. Naked-eye sensing of various caffeine concentrations was possible based on color changes upon irradiation with a laser pointer. Lastly, we performed the whole system on a microfluidic device to make caffeine detection quick, sensitive and automated. PMID:23877095

  6. Caffeine in Pregnancy

    MedlinePlus

    ... much caffeine they contain. Is caffeine safe during breastfeeding? The American Academy of Pediatrics (AAP) says it’s ... much caffeine they contain. Is caffeine safe during breastfeeding? The American Academy of Pediatrics (AAP) says it’s ...

  7. Caffeine in the diet

    MedlinePlus

    Diet - caffeine ... Caffeine is absorbed and passes quickly into the brain. It does not collect in the bloodstream or ... been consumed. There is no nutritional need for caffeine. It can be avoided in the diet. Caffeine ...

  8. The best defense against hypoglycemia is to recognize it: is caffeine useful?

    PubMed

    Watson, J; Kerr, D

    1999-01-01

    Caffeine, 1,3,7trimethylxanthine, is used by 80% of the adult population of the world in its various forms. Even the simple pleasure of consuming this socially acceptable drug has implications for the person with diabetes mellitus. Caffeine may increase an individual's sensitivity to hypoglycemia through the combined effects of reducing substrate delivery to the brain via constriction of the cerebral arteries, whilst simultaneously increasing brain glucose metabolism and augmenting catecholamine production. This article summarizes the evidence supporting the hypothesis that caffeine influences the perception of and physiological response to hypoglycemia. Under laboratory conditions, acute ingestion of caffeine markedly enhances the symptomatic and sympathoadrenal responses to hypoglycemia in both healthy volunteers and patients with type 1 diabetes. Recently a study of free-living people with type 1 diabetes showed that caffeine consumption increased the awareness of hypoglycemia. Caffeine has been associated with a number of negative effects and addiction. Most serious of these associations are ischemic heart disease and hypertension, the relationships have not been clearly established and the evidence to date is controversial. Thus we conclude that in modest doses, caffeine may be a useful adjuvant therapy for patients with hypoglycemia unawareness. For once here is a therapy which is inexpensive, safe, and remarkably popular with its consumers. PMID:11475292

  9. Dietary Caffeine and Polyphenol Supplementation Enhances Overall Metabolic Rate and Lipid Oxidation at Rest and After a Bout of Sprint Interval Exercise.

    PubMed

    Jo, Edward; Lewis, Kiana L; Higuera, Daniel; Hernandez, Joshua; Osmond, Adam D; Directo, Dean J; Wong, Michael

    2016-07-01

    Jo, E, Lewis, KL, Higuera, D, Hernandez, J, Osmond, AD, Directo, DJ, and Wong, M. Dietary caffeine and polyphenol supplementation enhances overall metabolic rate and lipid oxidation at rest and after a bout of sprint interval exercise. J Strength Cond Res 30(7): 1871-1879, 2016-The purpose of this study was to investigate the effects of a caffeine-polyphenolic supplement on (a) metabolic rate and fat oxidation at rest and after a bout of sprint interval exercise (SIE) and (b) SIE performance. In a double-blind, randomized, placebo-controlled, crossover study and after an initial familiarization visit, 12 subjects (male: n = 11; female: n = 1) (body mass = 76.1 ± 2.2 kg; height = 169.8 ± 1.6 cm; body mass index = 22.7 ± 3.0 kg·m; body fat % = 21.6 ± 2.0%) underwent 2 testing sessions during which time they consumed either a caffeine-polyphenol supplement or placebo. After supplementation, resting energy expenditure, heart rate (HR), and blood pressure (BP) were assessed. Subsequently, subjects performed 30 minutes of SIE while researchers collected performance data. Subjects were then tested for post-SIE energy expenditure, HR, and BP. The caffeine-polyphenol treatment resulted in significantly (p ≤ 0.05) greater energy expenditure (+7.99% rest; +10.16% post-SIE), V[Combining Dot Above]O2 (+9.64% rest; +12.10% post-SIE), and fat oxidation rate (+10.60% rest; +9.76% post-SIE) vs. placebo at rest and post-SIE. No significant differences were detected for peak and average power at all sprint intervals between treatments. Post-SIE HR was significantly (p ≤ 0.05) greater with caffeine-polyphenol supplementation vs. placebo (90.8 ± 3.5 vs. 85.1 ± 3.6 b·min). There were no significant between-treatment differences for BP. It may be concluded that the observed thermogenic response after SIE was directly attributable to caffeine-polyphenol supplementation as opposed to an indirect manifestation of enhanced performance and work output. Collectively, these results

  10. Caffeine enhances the antidepressant-like activity of common antidepressant drugs in the forced swim test in mice.

    PubMed

    Szopa, Aleksandra; Poleszak, Ewa; Wyska, Elżbieta; Serefko, Anna; Wośko, Sylwia; Wlaź, Aleksandra; Pieróg, Mateusz; Wróbel, Andrzej; Wlaź, Piotr

    2016-02-01

    Caffeine is the most widely used behaviorally active drug in the world which exerts its activity on central nervous system through adenosine receptors. Worrying data indicate that excessive caffeine intake applies to patients suffering from mental disorders, including depression. The main goal of the present study was to evaluate the influence of caffeine on animals' behavior in forced swim test (FST) as well as the effect of caffeine (5 mg/kg) on the activity of six typical antidepressants, such as imipramine (15 mg/kg), desipramine (10 mg/kg), fluoxetine (5 mg/kg), paroxetine (0.5 mg/kg), escitalopram (2 mg/kg), and reboxetine (2.5 mg/kg). Locomotor activity was estimated to verify and exclude false-positive/negative results. In order to assess the influence of caffeine on the levels of antidepressant drugs studied, their concentrations were determined in murine serum and brains using high-performance liquid chromatography. The results showed that caffeine at a dose of 10, 20, and 50 mg/kg exhibited antidepressant activity in the FST, and it was not related to changes in locomotor activity in the animals. Caffeine at a dose of 5 mg/kg potentiated the activity of all antidepressants, and the observed effects were not due to the increase in locomotor activity in the animals. The interactions between caffeine and desipramine, fluoxetine, escitalopram, and reboxetine were exclusively of pharmacodynamic character, because caffeine did not cause any changes in the concentrations of these drugs neither in blood serum nor in brain tissue. As a result of joint administration of caffeine and paroxetine, an increase in the antidepressant drug concentrations in serum was observed. No such change was noticed in the brain tissue. A decrease in the antidepressant drug concentrations in brain was observed in the case of imipramine administered together with caffeine. Therefore, it can be assumed that the interactions caffeine-paroxetine and caffeine-imipramine occur at least in

  11. Caffeine tolerance: behavioral, electrophysiological and neurochemical evidence

    SciTech Connect

    Chou, D.T.; Khan, S.; Forde, J.; Hirsh, K.R.

    1985-06-17

    The development of tolerance to the stimulatory action of caffeine upon mesencephalic reticular neurons and upon spontaneous locomotor activity was evaluated in rats after two weeks of chronic exposure to low doses of caffeine (5-10 mg/kg/day via their drinking water). These doses are achievable through dietary intake of caffeine-containing beverages in man. Concomitant measurement of (/sup 3/H)-CHA binding in the mesencephalic reticular formation was also carried out in order to explore the neurochemical basis of the development of tolerance. Caffeine, 2.5 mg/kg i.v., markedly increased the firing rate of reticular neurons in caffeine naive rats but failed to modify the neuronal activity in a group exposed chronically to low doses of caffeine. In addition, in spontaneous locomotor activity studies, the data show a distinct shift to the right of the caffeine dose-response curve in caffeine pretreated rats. These results clearly indicate that tolerance develops to the stimulatory action of caffeine upon the reticular formation at the single neuronal activity level as well as upon spontaneous locomotor activity. Furthermore, in chronically caffeine exposed rats, an increase in the number of binding sites for (/sup 3/H)-CHA was observed in reticular formation membranes without any change in receptor affinity. 28 references, 4 figures.

  12. Enhancing the IMS QTI to Better Support Computer Assisted Marking

    ERIC Educational Resources Information Center

    Clark, Damien; Baillie-de Byl, Penny

    2007-01-01

    Computer aided assessment is a common approach used by educational institutions. The benefits range into the design of teaching, learning, and instructional materials. While some such systems implement fully automated marking for multiple choice questions and fill-in-the-blanks, they are insufficient when human critiquing is required. Current…

  13. Caffeine and Migraine

    MedlinePlus

    ... disabling headaches . Home > Caffeine and Migraine Print Email Caffeine and Migraine ACHE Newsletter Sign up for our newsletter by entering your e-mail address below. Caffeine and Migraine Robert E. Shapiro, MD, PhD and ...

  14. Marked point processes for enhancing seismic fault patterns

    NASA Astrophysics Data System (ADS)

    Barna, Keresztes; Szirányi, Tamás; Borda, Monica; Lavialle, Olivier

    2015-07-01

    In this paper we present a new method for fault extraction in seismic blocks, using marked point processes. Our goal is to increase the detection accuracy of the state of the art fault attributes by computing them on a system of objects based on an a priori knowledge about the faults. An original curved support has been developed to describe the faults in vertical sections of the seismic blocks. The results are compared with the previous models used for linear network extraction, such as the Candy model. Synthetic blocks were used to compare the results obtained thanks to the point processes with the classical attributes. To segment the whole blocks, a multi-2D approach was used. Several modifications of the algorithm were necessary in order to make the results easier to interpret for geologists. One interest of the high-level approach offered by the marked point processes is the possibility of using the objects as a common support for various fault detection operators. A whole detection framework can be proposed which acts like a decision fusion process.

  15. Ancillary therapies to enhance success of non-invasive modes of respiratory support - Approaches to delivery room use of surfactant and caffeine?

    PubMed

    Kribs, Angela; Hummler, Helmut

    2016-06-01

    During recent decades, non-invasive respiratory support has become popular for treating neonates with respiratory failure. Several prospective randomized controlled trials have been performed to compare use of continuous positive airway pressure (CPAP) as primary respiratory support in preterm infants with respiratory distress syndrome (RDS) to endotracheal intubation, mechanical ventilation and surfactant therapy. Systematic reviews of these studies suggest that routine CPAP at delivery is efficacious in decreasing bronchopulmonary dysplasia (BPD), death, or both. This led to the recommendation to consider CPAP to avoid endotracheal intubation. As surfactant therapy is known to reduce BPD and death, several ways to combine CPAP with surfactant have been described. With the increasing use of CPAP immediately after birth, the early use of caffeine to stimulate respiration has become a point of discussion. This review focuses on different modes of surfactant application during CPAP and on the early use of caffeine as ancillary therapies to enhance CPAP success. PMID:26936187

  16. Caffeine, exercise and the brain.

    PubMed

    Meeusen, Romain; Roelands, Bart; Spriet, Lawrence L

    2013-01-01

    Caffeine can improve exercise performance when it is ingested at moderate doses (3-6 mg/kg body mass). Caffeine also has an effect on the central nervous system (CNS), and it is now recognized that most of the performance-enhancing effect of caffeine is accomplished through the antagonism of the adenosine receptors, influencing the dopaminergic and other neurotransmitter systems. Adenosine and dopamine interact in the brain, and this might be one mechanism to explain how the important components of motivation (i.e. vigor, persistence and work output) and higher-order brain processes are involved in motor control. Caffeine maintains a higher dopamine concentration especially in those brain areas linked with 'attention'. Through this neurochemical interaction, caffeine improves sustained attention, vigilance, and reduces symptoms of fatigue. Other aspects that are localized in the CNS are a reduction in skeletal muscle pain and force sensation, leading to a reduction in perception of effort during exercise and therefore influencing the motivational factors to sustain effort during exercise. Because not all CNS aspects have been examined in detail, one should consider that a placebo effect may also be present. Overall, it appears that the performance-enhancing effects of caffeine reside in the brain, although more research is necessary to reveal the exact mechanisms through which the CNS effect is established. PMID:23899750

  17. Dynamic hydroxymethylation of deoxyribonucleic acid marks differentiation-associated enhancers

    PubMed Central

    Sérandour, Aurélien A.; Avner, Stéphane; Oger, Frédérik; Bizot, Maud; Percevault, Frédéric; Lucchetti-Miganeh, Céline; Palierne, Gaëlle; Gheeraert, Céline; Barloy-Hubler, Frédérique; Péron, Christine Le; Madigou, Thierry; Durand, Emmanuelle; Froguel, Philippe; Staels, Bart; Lefebvre, Philippe; Métivier, Raphaël; Eeckhoute, Jérôme; Salbert, Gilles

    2012-01-01

    Enhancers are developmentally controlled transcriptional regulatory regions whose activities are modulated through histone modifications or histone variant deposition. In this study, we show by genome-wide mapping that the newly discovered deoxyribonucleic acid (DNA) modification 5-hydroxymethylcytosine (5hmC) is dynamically associated with transcription factor binding to distal regulatory sites during neural differentiation of mouse P19 cells and during adipocyte differentiation of mouse 3T3-L1 cells. Functional annotation reveals that regions gaining 5hmC are associated with genes expressed either in neural tissues when P19 cells undergo neural differentiation or in adipose tissue when 3T3-L1 cells undergo adipocyte differentiation. Furthermore, distal regions gaining 5hmC together with H3K4me2 and H3K27ac in P19 cells behave as differentiation-dependent transcriptional enhancers. Identified regions are enriched in motifs for transcription factors regulating specific cell fates such as Meis1 in P19 cells and PPARγ in 3T3-L1 cells. Accordingly, a fraction of hydroxymethylated Meis1 sites were associated with a dynamic engagement of the 5-methylcytosine hydroxylase Tet1. In addition, kinetic studies of cytosine hydroxymethylation of selected enhancers indicated that DNA hydroxymethylation is an early event of enhancer activation. Hence, acquisition of 5hmC in cell-specific distal regulatory regions may represent a major event of enhancer progression toward an active state and participate in selective activation of tissue-specific genes. PMID:22730288

  18. Caffeine reduces myocardial blood flow during exercise.

    PubMed

    Higgins, John P; Babu, Kavita M

    2013-08-01

    Caffeine consumption has been receiving increased interest from both the medical and lay press, especially given the increased amounts now available in energy products. Acute ingestion of caffeine usually increases cardiac work; however, caffeine impairs the expected proportional increase in myocardial blood flow to match this increased work of the heart, most notably during exercise. This appears to be mainly due to caffeine's effect on blocking adenosine-induced vasodilatation in the coronary arteries in normal healthy subjects. This review summarizes the available medical literature specifically relating to pure caffeine tablet ingestion and reduced exercise coronary blood flow, and suggests possible mechanisms. Further studies are needed to evaluate this effect for other common caffeine-delivery systems, including coffee, energy beverages, and energy gels, which are often used for exercise performance enhancement, especially in teenagers and young athletes. PMID:23764265

  19. Topical and transdermal delivery of caffeine.

    PubMed

    Luo, Lin; Lane, Majella E

    2015-07-25

    Caffeine is administered topically and transdermally for a variety of pharmaceutical and cosmetic applications and it is also used as a model hydrophilic compound in dermal risk assessment studies. This review considers the physicochemical and permeation properties of caffeine with reference to its delivery to and through the skin. Since it has been used as a model compound the findings have implications for the delivery of many hydrophilic compounds having similar properties. Various passive and active formulation strategies to promote enhanced skin permeation of caffeine are considered. Models to study percutaneous caffeine penetration are also discussed in detail. PMID:26004004

  20. Caffeine Expectancy Questionnaire (CaffEQ): construction, psychometric properties, and associations with caffeine use, caffeine dependence, and other related variables.

    PubMed

    Huntley, Edward D; Juliano, Laura M

    2012-09-01

    Expectancies for drug effects predict drug initiation, use, cessation, and relapse, and may play a causal role in drug effects (i.e., placebo effects). Surprisingly little is known about expectancies for caffeine even though it is the most widely used psychoactive drug in the world. In a series of independent studies, the nature and scope of caffeine expectancies among caffeine consumers and nonconsumers were assessed, and a comprehensive and psychometrically sound Caffeine Expectancy Questionnaire (CaffEQ) was developed. After 2 preliminary studies, the CaffEQ was administered to 1,046 individuals from the general population along with other measures of interest (e.g., caffeine use history, anxiety). Exploratory factor analysis of the CaffEQ yielded a 7-factor solution. Subsequently, an independent sample of 665 individuals completed the CaffEQ and other measures, and a subset (n = 440) completed the CaffEQ again approximately 2 weeks later. Confirmatory factor analysis revealed good model fit, and test-retest reliability was very good. The frequency and quantity of caffeine use were associated with greater expectancies for withdrawal/dependence, energy/work enhancement, appetite suppression, social/mood enhancement, and physical performance enhancement and lower expectancies for anxiety/negative physical effects and sleep disturbance. Caffeine expectancies predicted various caffeine- associated features of substance dependence (e.g., use despite harm, withdrawal incidence and severity, perceived difficulty stopping use, tolerance). Expectancies for caffeine consumed via coffee were stronger than for caffeine consumed via soft drinks or tea. The CaffEQ should facilitate the advancement of our knowledge of caffeine and drug use in general. PMID:22149323

  1. A hypothalamic–pituitary–adrenal axis-associated neuroendocrine metabolic programmed alteration in offspring rats of IUGR induced by prenatal caffeine ingestion

    SciTech Connect

    Xu, D.; Wu, Y.; Liu, F.; Liu, Y.S.; Shen, L.; Lei, Y.Y.; Liu, J.; Ping, J.; Qin, J.; Zhang, C.; Chen, L.B.; Magdalou, J.; Wang, H.

    2012-11-01

    Caffeine is a definite factor of intrauterine growth retardation (IUGR). Previously, we have confirmed that prenatal caffeine ingestion inhibits the development of hypothalamic–pituitary–adrenal (HPA) axis, and alters the glucose and lipid metabolism in IUGR fetal rats. In this study, we aimed to verify a programmed alteration of neuroendocrine metabolism in prenatal caffeine ingested-offspring rats. The results showed that prenatal caffeine (120 mg/kg.day) ingestion caused low body weight and high IUGR rate of pups; the concentrations of blood adrenocorticotropic hormone (ACTH) and corticosterone in caffeine group were significantly increased in the early postnatal period followed by falling in late stage; the level of blood glucose was unchanged, while blood total cholesterol (TCH) and triglyceride (TG) were markedly enhanced in adult. After chronic stress, the concentrations and the gain rates of blood ACTH and corticosterone were obviously increased, meanwhile, the blood glucose increased while the TCH and TG decreased in caffeine group. Further, the hippocampal mineralocorticoid receptor (MR) expression in caffeine group was initially decreased and subsequently increased after birth. After chronic stress, the 11β-hydroxysteroid dehydrogenase-1, glucocorticoid receptor (GR), MR as well as the MR/GR ratio were all significantly decreased. These results suggested that prenatal caffeine ingestion induced the dysfunction of HPA axis and associated neuroendocrine metabolic programmed alteration in IUGR offspring rats, which might be related with the functional injury of hippocampus. These observations provide a valuable experimental basis for explaining the susceptibility of IUGR offspring to metabolic syndrome and associated diseases. -- Highlights: ► Prenatal caffeine ingestion induced HPA axis dysfunction in IUGR offspring rats. ► Caffeine induced a neuroendocrine metabolic programmed alteration in offspring rats. ► Caffeine induced a functional injury

  2. Human Erythropoietin Dimers with Markedly Enhanced in vivo Activity

    NASA Astrophysics Data System (ADS)

    Sytkowski, Arthur J.; Dotimas Lunn, Elizabeth; Davis, Kerry Lynn; Feldman, Laurie; Siekman, Suvia

    1998-02-01

    Human erythropoietin, a widely used and important therapeutic glycoprotein, has a relatively short plasma half-life due to clearance by glomerular filtration as well as by other mechanisms. We hypothesized that an erythropoietin species with a larger molecular size would exhibit an increased plasma half-life and, potentially, an enhanced biological activity. We now report the production of biologically active erythropoietin dimers and trimers by chemical crosslinking of the conventional monomeric form. We imparted free sulfhydryl residues to a pool of erythropoietin monomer by chemical modification. A second pool was reacted with another modifying reagent to yield monomer with male-imido groups. Upon mixing these two pools, covalently linked dimers and trimers were formed that were biologically active in vitro. The plasma half-life of erythropoietin dimers in rabbits was >24 h compared with 4 h for the monomers. Importantly, erythropoietin dimers were biologically active in vivo as shown by their ability to increase the hematocrits of mice when injected subcutaneously. In addition, the dimers exhibited >26-fold higher activity in vivo than did the monomers and were very effective after only one dose. Dimeric and other oligomeric forms of Epo may have an important role in therapy.

  3. Caffeine Toxicity Due to Supplement Use in Caffeine--Naïve Individual: A Cautionary Tale.

    PubMed

    Lystrup, Robert M; Leggit, Jeffery C

    2015-08-01

    Thousands of military members self-medicate with dietary supplements containing unknown quantities of pharmacologically active compounds. These poorly regulated substances can cause real harm to the military population, especially when they contain stimulants such as caffeine. When taken regularly, caffeine has several performance-enhancing benefits. However, when used excessively or in vulnerable populations, caffeine can cause several unwanted side effects such as nervousness, sensory disturbances, insomnia, arrhythmia, excitability, inattentiveness, restlessness, mood changes, gastrointestinal disturbances, and even psychosis. Vulnerable patients include the caffeine-naïve, physiologically stressed, young, and mentally ill patients. One such case describes a caffeine-naïve service member who suffered an adverse reaction after taking an allegedly moderate dose of caffeine from a pill he obtained from a teammate. This case highlights the importance of supplement awareness among service members, increased provider vigilance, third party verification, and enhanced regulation on the approval and marketing of dietary supplements. PMID:26226540

  4. Wet powder suspensions as an additional technique for the enhancement of bloodied marks.

    PubMed

    Au, Catherine; Jackson-Smith, Hayley; Quinones, Ignacio; Jones, B J; Daniel, Barbara

    2011-01-30

    The enhancement of marks in blood on dark surfaces poses significant challenges to the forensic scientist. Current methods of enhancement include the sequential use of acid dyes (acid yellow, acid violet and acid black). Acid yellow is used to greatest effect on lighter deposits of blood on a non-porous background, and is visualised using a light source which causes it to fluoresce [1]. However, further enhancement with acid violet and acid black produces a dark product which may fail to improve the contrast of the mark against a dark background. The use of wet powder suspensions (WPSs) has been proposed as a complementary procedure for use in fingermark enhancement, beyond its typical use in the enhancement of marks on adhesive surfaces. In this investigation, the use of WPS was tested in conjunction with conventional acid dye treatments on marks in blood deposited on a selection of substrates. The results demonstrated that white WPS alone or together with acid dyes results in an overall enhancement of mark quality (p<0.005) on marks deposited on smooth non-porous surfaces. The technique was shown to not interfere with subsequent presumptive tests on blood. However WPS treatments were shown to reduce the amount of DNA recoverable from the marks, resulting on an average decrease of 91% compared to untreated controls. The decline in DNA yields was shown to result in a decrease in the quality of the DNA profiles obtained. The enhancement properties of WPS were evaluated by electron microscopy. It was shown that the titanium dioxide particles in the WPS primarily interact with the non-bloodied part of the mark, thus producing a contrasting effect with the background and acid dyes. PMID:20494531

  5. Caffeine fostering of mycoparasitic fungi against phytopathogens.

    PubMed

    Sugiyama, Akifumi; Sano, Cecile M; Yazaki, Kazufumi; Sano, Hiroshi

    2016-01-01

    Caffeine (1,3,7-trimethixanthine) is a typical purine alkaloid produced in more than 80 plant species. Its biological role is considered to strengthen plant's defense capabilities, directly as a toxicant to biotic attackers (allelopathy) and indirectly as an activator of defense system (priming). Caffeine is actively secreted into rhizosphere through primary root, and possibly affects the structure of microbe community nearby. The fungal community in coffee plant rhizosphere is enriched with particular species, including Trichoderma family, a mycoparasite that attacks and kills phytopathogens by coiling and destroying their hyphae. In the present study, the caffeine response of 8 filamentous fungi, 4 mycoparasitic Trichoderma, and 4 prey phytopathogens, was examined. Results showed that allelopathic effect of caffeine on fungal growth and development was differential, being stronger on pathogens than on Trichoderma species. Upon confronting, the prey immediately ceased the growth, whereas the predator continued to grow, indicating active mycoparasitism to have occurred. Caffeine enhanced mycoparasitism up to 1.7-fold. Caffeine thus functions in a double-track manner against fungal pathogens: first by direct suppression of growth and development, and second by assisting their natural enemy. These observations suggest that caffeine is a powerful weapon in the arms race between plants and pathogens by fostering enemy's enemy, and we propose the idea of "caffeine fostering" as the third role of caffeine. PMID:26529400

  6. Caffeine fostering of mycoparasitic fungi against phytopathogens

    PubMed Central

    Sugiyama, Akifumi; Sano, Cecile M.; Yazaki, Kazufumi; Sano, Hiroshi

    2016-01-01

    Caffeine (1,3,7-trimethixanthine) is a typical purine alkaloid produced in more than 80 plant species. Its biological role is considered to strengthen plant's defense capabilities, directly as a toxicant to biotic attackers (allelopathy) and indirectly as an activator of defense system (priming). Caffeine is actively secreted into rhizosphere through primary root, and possibly affects the structure of microbe community nearby. The fungal community in coffee plant rhizosphere is enriched with particular species, including Trichoderma family, a mycoparasite that attacks and kills phytopathogens by coiling and destroying their hyphae. In the present study, the caffeine response of 8 filamentous fungi, 4 mycoparasitic Trichoderma, and 4 prey phytopathogens, was examined. Results showed that allelopathic effect of caffeine on fungal growth and development was differential, being stronger on pathogens than on Trichoderma species. Upon confronting, the prey immediately ceased the growth, whereas the predator continued to grow, indicating active mycoparasitism to have occurred. Caffeine enhanced mycoparasitism up to 1.7-fold. Caffeine thus functions in a double-track manner against fungal pathogens: first by direct suppression of growth and development, and second by assisting their natural enemy. These observations suggest that caffeine is a powerful weapon in the arms race between plants and pathogens by fostering enemy's enemy, and we propose the idea of "caffeine fostering" as the third role of caffeine. PMID:26529400

  7. Effect of caffeine on induction of endogenous type C virus in mouse cells in vitro

    SciTech Connect

    Niwa, O.; Sugahara, T.

    1981-08-01

    The effect of caffeine on the expression of murine endogenous virus in mouse cells induced by radiation and chemicals was studied. Postirradiation treatment of K-BALB cells with caffeine enhanced cell killing as well as the induction of xenotropic virus after ultraviolet light irradiation. The degree of enhancement for the virus induction was comparable to that for cell killing. On the other hand, colony-forming ability and the expression of xenotropic virus of K-BALB cells after X-irradiation were unaffected by caffeine. These data suggest a linear relationship between the degree of endogenous virus expression and the amount of lethal damages after irradiation. For induction by halogenated pyrimidines, a 24-hr incubation of AKR2B cells with caffeine after 5-iodo-2'-deoxyuridine treatment resulted in marked suppression of the expression of ecotropic virus. On the contrary, in K-BALB cells, caffeine exerted only a small effect on 5-iodo-2'-deoxyuridine-induced expression of ecotropic and xenotropic viruses. These results indicate that, although using the same inducing agent, the pathway of endogenous virus induction may be different for AKR2B cells and for K-BALB cells.

  8. Caffeine and exercise: metabolism, endurance and performance.

    PubMed

    Graham, T E

    2001-01-01

    Caffeine is a common substance in the diets of most athletes and it is now appearing in many new products, including energy drinks, sport gels, alcoholic beverages and diet aids. It can be a powerful ergogenic aid at levels that are considerably lower than the acceptable limit of the International Olympic Committee and could be beneficial in training and in competition. Caffeine does not improve maximal oxygen capacity directly, but could permit the athlete to train at a greater power output and/or to train longer. It has also been shown to increase speed and/or power output in simulated race conditions. These effects have been found in activities that last as little as 60 seconds or as long as 2 hours. There is less information about the effects of caffeine on strength; however, recent work suggests no effect on maximal ability, but enhanced endurance or resistance to fatigue. There is no evidence that caffeine ingestion before exercise leads to dehydration, ion imbalance, or any other adverse effects. The ingestion of caffeine as coffee appears to be ineffective compared to doping with pure caffeine. Related compounds such as theophylline are also potent ergogenic aids. Caffeine may act synergistically with other drugs including ephedrine and anti-inflammatory agents. It appears that male and female athletes have similar caffeine pharmacokinetics, i.e., for a given dose of caffeine, the time course and absolute plasma concentrations of caffeine and its metabolites are the same. In addition, exercise or dehydration does not affect caffeine pharmacokinetics. The limited information available suggests that caffeine non-users and users respond similarly and that withdrawal from caffeine may not be important. The mechanism(s) by which caffeine elicits its ergogenic effects are unknown, but the popular theory that it enhances fat oxidation and spares muscle glycogen has very little support and is an incomplete explanation at best. Caffeine may work, in part, by

  9. Caffeine Promotes Global Spatial Processing in Habitual and Non-Habitual Caffeine Consumers

    PubMed Central

    Giles, Grace E.; Mahoney, Caroline R.; Brunyé, Tad T.; Taylor, Holly A.; Kanarek, Robin B.

    2013-01-01

    Information processing is generally biased toward global cues, often at the expense of local information. Equivocal extant data suggests that arousal states may accentuate either a local or global processing bias, at least partially dependent on the nature of the manipulation, task, and stimuli. To further differentiate the conditions responsible for such equivocal results we varied caffeine doses to alter physiological arousal states and measured their effect on tasks requiring the retrieval of local versus global spatial knowledge. In a double-blind, repeated-measures design, non-habitual (Experiment 1; N = 36, M = 42.5 ± 28.7 mg/day caffeine) and habitual (Experiment 2; N = 34, M = 579.5 ± 311.5 mg/day caffeine) caffeine consumers completed four test sessions corresponding to each of four caffeine doses (0, 100, 200, 400 mg). During each test session, participants consumed a capsule containing one of the three doses of caffeine or placebo, waited 60 min, and then completed two spatial tasks, one involving memorizing maps and one spatial descriptions. A spatial statement verification task tested local versus global spatial knowledge by differentially probing memory for proximal versus distal landmark relationships. On the map learning task, results indicated that caffeine enhanced memory for distal (i.e., global) compared to proximal (i.e., local) comparisons at 100 (marginal), 200, and 400 mg caffeine in non-habitual consumers, and marginally beginning at 200 mg caffeine in habitual consumers. On the spatial descriptions task, caffeine enhanced memory for distal compared to proximal comparisons beginning at 100 mg in non-habitual but not habitual consumers. We thus provide evidence that caffeine-induced physiological arousal amplifies global spatial processing biases, and these effects are at least partially driven by habitual caffeine consumption. PMID:24146646

  10. Acetaminophen, Butalbital, and Caffeine

    MedlinePlus

    The combination of acetaminophen, Butalbital, Caffeine comes as a capsule and tablet to take by mouth. It usually is taken every 4 hours ... explain any part you do not understand. Take acetaminophen, Butalbital, Caffeine exactly as directed. Do not take ...

  11. Adolescent Caffeine Consumption and Self-Reported Violence and Conduct Disorder

    ERIC Educational Resources Information Center

    Kristjansson, Alfgeir L.; Sigfusdottir, Inga Dora; Frost, Stephanie S.; James, Jack E.

    2013-01-01

    Caffeine is the most widely used psychoactive substance in the world and currently the only one legally available to children and adolescents. The sale and use of caffeinated beverages has increased markedly among adolescents during the last decade. However, research on caffeine use and behaviors among adolescents is scarce. We investigate the…

  12. Caffeine Content Labeling: A Missed Opportunity for Promoting Personal and Public Health

    PubMed Central

    Kole, Jon

    2013-01-01

    Current regulation of caffeine-containing products is incoherent, fails to protect consumers' interests, and should be modified in multiple ways. We make the case for one of the regulatory reforms that are needed: all consumable products containing added caffeine should be required by the Food and Drug Administration (FDA) to include caffeine quantity on their labels. Currently, no foods or beverages that contain caffeine are required to include caffeine content on their labels. Strengthening these lax labeling requirements could prevent direct caffeine-induced harm, protect those most vulnerable to caffeine-related side effects, and enhance consumer autonomy and effective caffeine use. Consumers have an interest in regulating their intake of caffeine and thus, ought to know how much caffeine their foods and beverages contain. PMID:24761278

  13. The pH dependent Raman spectroscopic study of caffeine

    NASA Astrophysics Data System (ADS)

    Kang, Jian; Gu, Huaimin; Zhong, Liang; Hu, Yongjun; Liu, Fang

    2011-02-01

    First of all the surface enhanced Raman spectroscopy (SERS) and normal Raman spectra of caffeine aqueous solution were obtained at different pH values. In order to obtain the detailed vibrational assignments of the Raman spectroscopy, the geometry of caffeine molecule was optimized by density functional theory (DFT) calculation. By comparing the SERS of caffeine with its normal spectra at different pH values; it is concluded that pH value can dramatically affect the SERS of caffeine, but barely affect the normal Raman spectrum of caffeine aqueous solution. It can essentially affect the reorientation of caffeine molecule to the Ag colloid surface, but cannot impact the vibration of functional groups and chemical bonds in caffeine molecule.

  14. Regular caffeine consumption: a balance of adverse and beneficial effects for mood and psychomotor performance.

    PubMed

    Rogers, P J; Dernoncourt, C

    1998-04-01

    It has often been pointed out that caffeine is the most widely "used" psychoactive substance in the world, and accordingly, there is a very large amount of research available on the effects of caffeine on body and mind. In particular, a psychostimulant action of caffeine is generally accepted as well established; for example, caffeine has been found to quicken reaction time and enhance vigilance performance, and to increase self-rated alertness and improve mood. There is, however, a real difficulty in determining the net effects of caffeine. In a typical experiment the subjects have a history of regular caffeine consumption, and they are tested on caffeine and a placebo after a period of caffeine deprivation (often overnight). The problem with relying solely on this approach is that it leaves open the question as to whether the results obtained are due to beneficial effects of caffeine or to deleterious effects of caffeine deprivation. The present article briefly reviews this evidence on the psychostimulant effects of caffeine, and presents some new data testing the hypothesis that caffeine may enhance cognitive performance to a greater extent in older adults than in young adults. No age-related differences in the effects of caffeine on psychomotor performance were found. We conclude that overall there is little unequivocal evidence to show that regular caffeine use is likely to substantially benefit mood or performance. Indeed, one of the significant factors motivating caffeine consumption appears to be "withdrawal relief." PMID:9586865

  15. Caffeine: Friend or Foe?

    PubMed

    Doepker, Candace; Lieberman, Harris R; Smith, Andrew Paul; Peck, Jennifer D; El-Sohemy, Ahmed; Welsh, Brian T

    2016-01-01

    The debate on the safety of and regulatory approaches for caffeine continues among various stakeholders and regulatory authorities. This decision-making process comes with significant challenges, particularly when considering the complexities of the available scientific data, making the formulation of clear science-based regulatory guidance more difficult. To allow for discussions of a number of key issues, the North American Branch of the International Life Sciences Institute (ILSI) convened a panel of subject matter experts for a caffeine-focused session entitled "Caffeine: Friend or Foe?," which was held during the 2015 ILSI Annual Meeting. The panelists' expertise covered topics ranging from the natural occurrence of caffeine in plants and interindividual metabolism of caffeine in humans to specific behavioral, reproductive, and cardiovascular effects related to caffeine consumption. Each presentation highlighted the potential risks, benefits, and challenges that inform whether caffeine exposure warrants concern. This paper aims to summarize the key topics discussed during the session. PMID:26735800

  16. Caffeine Consumption by College Undergraduates.

    ERIC Educational Resources Information Center

    Loke, Wing Hong

    1988-01-01

    Surveyed 542 undergraduates concerning their caffeine consumption. Found that subjects consumed less caffeine than average caffeine-drinking population. Coffee was main beverage used. Subjects reported drinking more caffeine when preparing for examinations. Suggests that caffeine may have some beneficial effects on learning. (Author/NB)

  17. Comparative percutaneous permeation study using caffeine-loaded microemulsion showing low reliability of the frozen/thawed skin models.

    PubMed

    Sintov, Amnon C; Greenberg, Igor

    2014-08-25

    The aim of this study was to explore the transdermal delivery potential of a new caffeine-containing microemulsion system. The skin permeability of caffeine (CAF) was measured in vitro using skin excised from three different animal species: rat, rabbit and pig. As shown, microemulsion containing 20% aqueous phase enhanced CAF permeation across fresh rat skin by one order of magnitude (Papp=8.2×10(-3) vs. 0.86×10(-3) cm/h; enhancement ratio=9.6). The permeability coefficient value, the cumulative permeation amount, and the percent of dose permeated after 24 h, decreased with the increase of water content from 60% to 80% in microemulsions due to the apparent increase in the droplet size. Importantly, differences were noted between caffeine transport rates across fresh and frozen/thawed pig skin whereas microemulsions delivered caffeine at similar rates across rat and rabbit skin, either fresh or frozen/thawed. It has been shown that the permeability of caffeine through frozen/thawed pig skin was abnormally high and was independent of its vehicle properties, i.e., its hydrophilic or lipophilic nature. It has been hypothesized that the reason for this abnormality is that porcine stratum corneum has a higher ceramide-to-cholesterol ratio compared to rat and rabbit skin. This unusual phenomenon observed in a non-freshly used porcine skin places a question mark on its suitability to in vitro evaluation of transdermal drug delivery systems. PMID:24866271

  18. Caffeine and anaerobic performance: ergogenic value and mechanisms of action.

    PubMed

    Davis, J K; Green, J Matt

    2009-01-01

    The effect caffeine elicits on endurance performance is well founded. However, comparatively less research has been conducted on the ergogenic potential of anaerobic performance. Some studies showing no effect of caffeine on performance used untrained subjects and designs often not conducive to observing an ergogenic effect. Recent studies incorporating trained subjects and paradigms specific to intermittent sports activity support the notion that caffeine is ergogenic to an extent with anaerobic exercise. Caffeine seems highly ergogenic for speed endurance exercise ranging in duration from 60 to 180 seconds. However, other traditional models examining power output (i.e. 30-second Wingate test) have shown minimal effect of caffeine on performance. Conversely, studies employing sport-specific methodologies (i.e. hockey, rugby, soccer) with shorter duration (i.e. 4-6 seconds) show caffeine to be ergogenic during high-intensity intermittent exercise. Recent studies show caffeine affects isometric maximal force and offers introductory evidence for enhanced muscle endurance for lower body musculature. However, isokinetic peak torque, one-repetition maximum and muscular endurance for upper body musculature are less clear. Since relatively few studies exist with resistance training, a definite conclusion cannot be reached on the extent caffeine affects performance. It was previously thought that caffeine mechanisms were associated with adrenaline (epinephrine)-induced enhanced free-fatty acid oxidation and consequent glycogen sparing, which is the leading hypothesis for the ergogenic effect. It would seem unlikely that the proposed theory would result in improved anaerobic performance, since exercise is dominated by oxygen-independent metabolic pathways. Other mechanisms for caffeine have been suggested, such as enhanced calcium mobilization and phosphodiesterase inhibition. However, a normal physiological dose of caffeine in vivo does not indicate this mechanism plays a

  19. Spectrophotometric Analysis of Caffeine.

    PubMed

    Ahmad Bhawani, Showkat; Fong, Sim Siong; Mohamad Ibrahim, Mohamad Nasir

    2015-01-01

    The nature of caffeine reveals that it is a bitter white crystalline alkaloid. It is a common ingredient in a variety of drinks (soft and energy drinks) and is also used in combination with various medicines. In order to maintain the optimum level of caffeine, various spectrophotometric methods have been developed. The monitoring of caffeine is very important aspect because of its consumption in higher doses that can lead to various physiological disorders. This paper incorporates various spectrophotometric methods used in the analysis of caffeine in various environmental samples such as pharmaceuticals, soft and energy drinks, tea, and coffee. A range of spectrophotometric methodologies including chemometric techniques and derivatization of spectra have been used to analyse the caffeine. PMID:26604926

  20. Spectrophotometric Analysis of Caffeine

    PubMed Central

    Ahmad Bhawani, Showkat; Fong, Sim Siong; Mohamad Ibrahim, Mohamad Nasir

    2015-01-01

    The nature of caffeine reveals that it is a bitter white crystalline alkaloid. It is a common ingredient in a variety of drinks (soft and energy drinks) and is also used in combination with various medicines. In order to maintain the optimum level of caffeine, various spectrophotometric methods have been developed. The monitoring of caffeine is very important aspect because of its consumption in higher doses that can lead to various physiological disorders. This paper incorporates various spectrophotometric methods used in the analysis of caffeine in various environmental samples such as pharmaceuticals, soft and energy drinks, tea, and coffee. A range of spectrophotometric methodologies including chemometric techniques and derivatization of spectra have been used to analyse the caffeine. PMID:26604926

  1. [Caffeine-induced contraction of guinea pig taenia coli (author's transl)].

    PubMed

    Takahashi, S; Chujyo, N

    1978-01-01

    Caffeine (10 or 20 mM)-induced isometric contraction of guinea pig taenia coli showed two successively occurring phasic contractions (I and II) followed by a low sustained tension. Half-time of tension decay in II was 4 approximately 6 times longer than in I. The contraction occasionally showed only a single phasic contraction, of which tension, however, decayed showing two half-times as in two phasic contractions. In the presence of procaine 0.1 approximately 0.5 mM, DNP 0.03 approximately 0.1 mM or Mn2+ 0.5 approximately 1.0 mM, II was entirely abolished whereas I was partially inhibited and such were confirmed by analyzing the time course of tension decay. Maximal tension of I decreased in parallel with lowering the external Na while II was enhanced with 50 approximately 100 mM Na and inhibited by further withdrawal of Na. I and II showed the same Ca-dependecy with respect to the inhibition by Ca deficiency and to the time course of recovery from Ca-free state. Refractoriness to caffeine after preceding caffeine-contraction also showed little difference between I and II. Sustained tension by caffeine was dependent on Ca in the same manner as tonic K-contracture. Increase in 45Ca uptake with 40 mM K was completely inhibited by 10 mM caffeine while cellular Ca content in the presence of high K markedly increased with caffeine indicating the decrease in Ca exchangeability. The above results indicate that caffeine induced contraction consists of two phasic contractions of which EC-coupling Ca is released from two different cellular sites, and that the phasic contractions are followed by a sustained low tension caused by an increased Ca influx. In the presence of high K, caffeine abolishes the increase in Ca influx by high K and sequesters the sarcoplasmic free Ca resulting in the relaxation of K-contracture. PMID:640536

  2. Exercise and sport performance with low doses of caffeine.

    PubMed

    Spriet, Lawrence L

    2014-11-01

    Caffeine is a popular work-enhancing supplement that has been actively researched since the 1970s. The majority of research has examined the effects of moderate to high caffeine doses (5-13 mg/kg body mass) on exercise and sport. These caffeine doses have profound effects on the responses to exercise at the whole-body level and are associated with variable results and some undesirable side effects. Low doses of caffeine (<3 mg/kg body mass, ~200 mg) are also ergogenic in some exercise and sport situations, although this has been less well studied. Lower caffeine doses (1) do not alter the peripheral whole-body responses to exercise; (2) improve vigilance, alertness, and mood and cognitive processes during and after exercise; and (3) are associated with few, if any, side effects. Therefore, the ergogenic effect of low caffeine doses appears to result from alterations in the central nervous system. However, several aspects of consuming low doses of caffeine remain unresolved and suffer from a paucity of research, including the potential effects on high-intensity sprint and burst activities. The responses to low doses of caffeine are also variable and athletes need to determine whether the ingestion of ~200 mg of caffeine before and/or during training and competitions is ergogenic on an individual basis. PMID:25355191

  3. International society of sports nutrition position stand: caffeine and performance

    PubMed Central

    2010-01-01

    Position Statement: The position of The Society regarding caffeine supplementation and sport performance is summarized by the following seven points: 1.) Caffeine is effective for enhancing sport performance in trained athletes when consumed in low-to-moderate dosages (~3-6 mg/kg) and overall does not result in further enhancement in performance when consumed in higher dosages (≥ 9 mg/kg). 2.) Caffeine exerts a greater ergogenic effect when consumed in an anhydrous state as compared to coffee. 3.) It has been shown that caffeine can enhance vigilance during bouts of extended exhaustive exercise, as well as periods of sustained sleep deprivation. 4.) Caffeine is ergogenic for sustained maximal endurance exercise, and has been shown to be highly effective for time-trial performance. 5.) Caffeine supplementation is beneficial for high-intensity exercise, including team sports such as soccer and rugby, both of which are categorized by intermittent activity within a period of prolonged duration. 6.) The literature is equivocal when considering the effects of caffeine supplementation on strength-power performance, and additional research in this area is warranted. 7.) The scientific literature does not support caffeine-induced diuresis during exercise, or any harmful change in fluid balance that would negatively affect performance. PMID:20205813

  4. International society of sports nutrition position stand: caffeine and performance.

    PubMed

    Goldstein, Erica R; Ziegenfuss, Tim; Kalman, Doug; Kreider, Richard; Campbell, Bill; Wilborn, Colin; Taylor, Lem; Willoughby, Darryn; Stout, Jeff; Graves, B Sue; Wildman, Robert; Ivy, John L; Spano, Marie; Smith, Abbie E; Antonio, Jose

    2010-01-01

    Position Statement: The position of The Society regarding caffeine supplementation and sport performance is summarized by the following seven points: 1.) Caffeine is effective for enhancing sport performance in trained athletes when consumed in low-to-moderate dosages (~3-6 mg/kg) and overall does not result in further enhancement in performance when consumed in higher dosages (>/= 9 mg/kg). 2.) Caffeine exerts a greater ergogenic effect when consumed in an anhydrous state as compared to coffee. 3.) It has been shown that caffeine can enhance vigilance during bouts of extended exhaustive exercise, as well as periods of sustained sleep deprivation. 4.) Caffeine is ergogenic for sustained maximal endurance exercise, and has been shown to be highly effective for time-trial performance. 5.) Caffeine supplementation is beneficial for high-intensity exercise, including team sports such as soccer and rugby, both of which are categorized by intermittent activity within a period of prolonged duration. 6.) The literature is equivocal when considering the effects of caffeine supplementation on strength-power performance, and additional research in this area is warranted. 7.) The scientific literature does not support caffeine-induced diuresis during exercise, or any harmful change in fluid balance that would negatively affect performance. PMID:20205813

  5. Caffeine in the diet

    MedlinePlus

    ... although many people still believe a cup of coffee will help a person "sober-up." Caffeine may ... than 60 plants, including: Tea leaves Kola nuts Coffee Cocoa beans It is also found in processed ...

  6. Mechanisms of Caffeine-Induced Inhibition of UVB Carcinogenesis.

    PubMed

    Conney, Allan H; Lu, Yao-Ping; Lou, You-Rong; Kawasumi, Masaoki; Nghiem, Paul

    2013-01-01

    Sunlight-induced non-melanoma skin cancer is the most prevalent cancer in the United States with more than two million cases per year. Several studies have shown an inhibitory effect of caffeine administration on UVB-induced skin cancer in mice, and these studies are paralleled by epidemiology studies that indicate an inhibitory effect of coffee drinking on non-melanoma skin cancer in humans. Strikingly, decaffeinated coffee consumption had no such inhibitory effect. Mechanism studies indicate that caffeine has a sunscreen effect that inhibits UVB-induced formation of thymine dimers and sunburn lesions in the epidermis of mice. In addition, caffeine administration has a biological effect that enhances UVB-induced apoptosis thereby enhancing the elimination of damaged precancerous cells, and caffeine administration also enhances apoptosis in tumors. Caffeine administration enhances UVB-induced apoptosis by p53-dependent and p53-independent mechanisms. Exploration of the p53-independent effect indicated that caffeine administration enhanced UVB-induced apoptosis by inhibiting the UVB-induced increase in ATR-mediated formation of phospho-Chk1 (Ser345) and abolishing the UVB-induced decrease in cyclin B1 which resulted in caffeine-induced premature and lethal mitosis in mouse skin. In studies with cultured primary human keratinocytes, inhibition of ATR with siRNA against ATR inhibited Chk1 phosphorylation and enhanced UVB-induced apoptosis. Transgenic mice with decreased epidermal ATR function that were irradiated chronically with UVB had 69% fewer tumors at the end of the study compared with irradiated littermate controls with normal ATR function. These results, which indicate that genetic inhibition of ATR (like pharmacologic inhibition of ATR via caffeine) inhibits UVB-induced carcinogenesis support the concept that ATR-mediated phosphorylation of Chk1 is an important target for caffeine's inhibitory effect on UVB-induced carcinogenesis. PMID:23785666

  7. Caffeine withdrawal symptoms and self-administration following caffeine deprivation.

    PubMed

    Mitchell, S H; de Wit, H; Zacny, J P

    1995-08-01

    This study examined the effects of complete or partial caffeine deprivation on withdrawal symptomatology and self-administration of coffee in caffeine-dependent coffee drinkers. Nine habitual coffee drinkers abstained from dietary sources of caffeine for 33.5 h. Caffeine deprivation was manipulated by administering capsules containing 0%, 50%, or 100% of each subject's daily caffeine intake (complete, partial, and no deprivation conditions). Caffeine withdrawal symptomatology was measured using self-report questionnaires. Caffeine self-administration was measured using: i) the amount of coffee subjects earned on a series of concurrent random-ratio schedules that yielded coffee and money reinforcers; ii) the amount of earned coffee they consumed. Saliva samples revealed that subjects complied with the caffeine abstinence instructions. Caffeine withdrawal symptoms occurred reliably following complete caffeine deprivation, though not in the partial deprivation condition. Caffeine self-administration was not related to deprivation condition. We conclude that caffeine withdrawal symptomatology is not necessarily associated with increased caffeine consumption. PMID:7675881

  8. Luminescence characteristics of caffeine and theophylline1

    NASA Astrophysics Data System (ADS)

    Andino, M. M.; De Lima, C. G.; Winefordner, J. D.

    The luminescence properties of solutions of caffeine and theophylline in methanol are observed. The effects of the solvent pH, the presence of a heavy atom and the matrix or substrate on the fluorescence and phosphorescence properties of the compounds are evaluated. Caffeine and theophylline fluorescence can be observed at room temperature from dilute methanolic solutions and strong phosphorescence is observed at low temperature when the matrix is in a polycrystalline state. Acidic and basic media cause spectral changes and reduce the intensity of the low temperature phosphorescence. Iodide is a good heavy-atom enhancer of both the low temperature and room temperature phosphorescence of caffeine and theophylline. The intensity of the phosphorescence at room temperature and when spotted on filter paper depends on the type of filter paper and the pH of the spotting solution and/or the pH of the wet surface at the moment of spotting. Theophylline is more sensitive than caffeine to the microenvironment. Under the appropriate experimental conditions, both low temperature and room temperature phosphorescence could be used as analytical tools for the determination of caffeine and theophylline.

  9. Caffeine content of decaffeinated coffee.

    PubMed

    McCusker, Rachel R; Fuehrlein, Brian; Goldberger, Bruce A; Gold, Mark S; Cone, Edward J

    2006-10-01

    Caffeine is the most widely consumed drug in the world with coffee representing a major source of intake. Despite widespread availability, various medical conditions necessitate caffeine-restricted diets. Patients on certain prescription medications are advised to discontinue caffeine intake. Such admonition has implications for certain psychiatric patients because of pharmacokinetic interactions between caffeine and certain anti-anxiety drugs. In an effort to abstain from caffeine, patients may substitute decaffeinated for caffeinated coffee. However, decaffeinated beverages are known to contain caffeine in varying amounts. The present study determined the caffeine content in a variety of decaffeinated coffee drinks. In phase 1 of the study, 10 decaffeinated samples were collected from different coffee establishments. In phase 2 of the study, Starbucks espresso decaffeinated (N=6) and Starbucks brewed decaffeinated coffee (N=6) samples were collected from the same outlet to evaluate variability of caffeine content of the same drink. The 10 decaffeinated coffee samples from different outlets contained caffeine in the range of 0-13.9 mg/16-oz serving. The caffeine content for the Starbucks espresso and the Starbucks brewed samples collected from the same outlet were 3.0-15.8 mg/shot and 12.0-13.4 mg/16-oz serving, respectively. Patients vulnerable to caffeine effects should be advised that caffeine may be present in coffees purported to be decaffeinated. Further research is warranted on the potential deleterious effects of consumption of "decaffeinated" coffee that contains caffeine on caffeine-restricted patients. Additionally, further exploration is merited for the possible physical dependence potential of low doses of caffeine such as those concentrations found in decaffeinated coffee. PMID:17132260

  10. SpDamID: Marking DNA Bound by Protein Complexes Identifies Notch-Dimer Responsive Enhancers

    PubMed Central

    Hass, Matthew R.; Liow, Hien-haw; Chen, Xiaoting; Sharma, Ankur; Inoue, Yukiko U.; Inoue, Takayoshi; Reeb, Ashley; Martens, Andrew; Fulbright, Mary; Raju, Saravanan; Stevens, Michael; Boyle, Scott; Park, Joo-Seop; Weirauch, Matthew T.; Brent, Michael; Kopan, Raphael

    2015-01-01

    SUMMARY We developed Split DamID (SpDamID), a protein complementation version of DamID, to mark genomic DNA bound in vivo by interacting or juxtapositioned transcription factors. Inactive halves of DAM (DNA Adenine Methyltransferase) were fused to protein pairs to be queried Interaction or proximity enabled DAM reconstitution and methylation of adenine in GATC. Inducible SpDamID was used to analyze Notch-mediated transcriptional activation. We demonstrate that Notch complexes label RBP sites broadly across the genome, and show that a subset of these complexes that recruit MAML and p300 undergo changes in chromatin accessibility in response to Notch signaling. SpDamID differentiates between monomeric and dimeric binding thereby allowing for identification of half-site motifs used by Notch dimers. Motif enrichment of Notch enhancers coupled with SpDamID reveals co-targeting of regulatory sequences by Notch and Runx1. SpDamID represents a sensitive and powerful tool that enables dynamic analysis of combinatorial protein-DNA transactions at a genome-wide level. PMID:26257285

  11. Retinoic Acid Specifically Enhances Embryonic Stem Cell Metastate Marked by Zscan4

    PubMed Central

    Tagliaferri, Daniela; De Angelis, Maria Teresa; Russo, Nicola Antonino; Marotta, Maria; Ceccarelli, Michele; Del Vecchio, Luigi; De Felice, Mario; Falco, Geppino

    2016-01-01

    Pluripotency confers Embryonic Stem Cells (ESCs) the ability to differentiate in ectoderm, endoderm, and mesoderm derivatives, producing the majority of cell types. Although the majority of ESCs divide without losing pluripotency, it has become evident that ESCs culture consists of multiple cell populations with different degrees of potency that are spontaneously induced in regular ESC culture conditions. Zscan4, a key pluripotency factor, marks ESC subpopulation that is referred to as high-level of pluripotency metastate. Here, we report that in ESC cultures treated with retinoic acid (RA), Zscan4 ESCs metastate is strongly enhanced. In particular, we found that induction of Zscan4 metastate is mediated via RA receptors (RAR-alpha, RAR-beta, and RAR-gamma), and it is dependent on phosphoinositide-3-kinase (PI3K) signaling. Remarkably, Zscan4 metastate induced by RA lacks canonical pluripotency genes Oct3/4 and Nanog but retained both self-renewal and pluripotency capabilities. Finally we demonstrated that the conditional ablation of Zscan4 subpopulation is dispensable for both endoderm and mesoderm but is required for ectoderm lineage. In conclusion, our research provides new insights about the role of RA signaling during ESCs high pluripotency metastate fluctuation. PMID:26840068

  12. Retinoic Acid Specifically Enhances Embryonic Stem Cell Metastate Marked by Zscan4.

    PubMed

    Tagliaferri, Daniela; De Angelis, Maria Teresa; Russo, Nicola Antonino; Marotta, Maria; Ceccarelli, Michele; Del Vecchio, Luigi; De Felice, Mario; Falco, Geppino

    2016-01-01

    Pluripotency confers Embryonic Stem Cells (ESCs) the ability to differentiate in ectoderm, endoderm, and mesoderm derivatives, producing the majority of cell types. Although the majority of ESCs divide without losing pluripotency, it has become evident that ESCs culture consists of multiple cell populations with different degrees of potency that are spontaneously induced in regular ESC culture conditions. Zscan4, a key pluripotency factor, marks ESC subpopulation that is referred to as high-level of pluripotency metastate. Here, we report that in ESC cultures treated with retinoic acid (RA), Zscan4 ESCs metastate is strongly enhanced. In particular, we found that induction of Zscan4 metastate is mediated via RA receptors (RAR-alpha, RAR-beta, and RAR-gamma), and it is dependent on phosphoinositide-3-kinase (PI3K) signaling. Remarkably, Zscan4 metastate induced by RA lacks canonical pluripotency genes Oct3/4 and Nanog but retained both self-renewal and pluripotency capabilities. Finally we demonstrated that the conditional ablation of Zscan4 subpopulation is dispensable for both endoderm and mesoderm but is required for ectoderm lineage. In conclusion, our research provides new insights about the role of RA signaling during ESCs high pluripotency metastate fluctuation. PMID:26840068

  13. SpDamID: Marking DNA Bound by Protein Complexes Identifies Notch-Dimer Responsive Enhancers.

    PubMed

    Hass, Matthew R; Liow, Hien-Haw; Chen, Xiaoting; Sharma, Ankur; Inoue, Yukiko U; Inoue, Takayoshi; Reeb, Ashley; Martens, Andrew; Fulbright, Mary; Raju, Saravanan; Stevens, Michael; Boyle, Scott; Park, Joo-Seop; Weirauch, Matthew T; Brent, Michael R; Kopan, Raphael

    2015-08-20

    We developed Split DamID (SpDamID), a protein complementation version of DamID, to mark genomic DNA bound in vivo by interacting or juxtapositioned transcription factors. Inactive halves of DAM (DNA adenine methyltransferase) were fused to protein pairs to be queried. Either direct interaction between proteins or proximity enabled DAM reconstitution and methylation of adenine in GATC. Inducible SpDamID was used to analyze Notch-mediated transcriptional activation. We demonstrate that Notch complexes label RBP sites broadly across the genome and show that a subset of these complexes that recruit MAML and p300 undergo changes in chromatin accessibility in response to Notch signaling. SpDamID differentiates between monomeric and dimeric binding, thereby allowing for identification of half-site motifs used by Notch dimers. Motif enrichment of Notch enhancers coupled with SpDamID reveals co-targeting of regulatory sequences by Notch and Runx1. SpDamID represents a sensitive and powerful tool that enables dynamic analysis of combinatorial protein-DNA transactions at a genome-wide level. PMID:26257285

  14. Development of tumor-specific caffeine-potentiated chemotherapy using a novel drug delivery system with Span 80 nano-vesicles.

    PubMed

    Nakata, Hiroshi; Miyazaki, Tatsuhiko; Iwasaki, Tomoyuki; Nakamura, Atsushi; Kidani, Teruki; Sakayama, Kenshi; Masumoto, Junya; Miura, Hiromasa

    2015-04-01

    In recent years, chemotherapy with caffeine has manifested potently high efficacy against osteosarcoma, although adverse effects have been observed. Recently, we developed a novel drug delivery system (DDS) with nonionic vesicles prepared from Span 80 which have promising physicochemical properties as an attractive possible alternative to commonly used liposomes. Herein, we demonstrated that tumor-specific caffeine-potentiated chemotherapy for murine osteosarcoma administered by a novel DDS with Span 80 nano-vesicles showed significant antitumor effects as well as limited adverse effects. The osteosarcoma cell line, LM8, was transplanted into C3H/HeJ mice which then were administered therapeutic agents. Ifosfamide (IFO) was employed as well as caffeine as an enhancer. Span 80 vesicles containing IFO and/or caffeine were freshly prepared. On days 0, 2 and 4, different combinations of the agents were administered to mice: IFO alone (direct i.v.), IFO vesicles (IV), IV+caffeine, IV+caffeine vesicles (CV), PBS alone vesicles (PV), and PBS alone as negative control (PBS i.v.). Then, the mice were sacrificed on day 7. Antitumor effects of the reagents were also analyzed in vitro. Moreover, fertility examination was performed. In vitro, a combination of IV+CV showed significant induction of apoptosis in the early phase. Tumor volumes in the IV+CV group were significantly reduced compared with the other groups. Histological analyses showed that the IV and IV+CV groups had significantly lower viable tumor areas. The IFO direct i.v. group showed a certain grade of renal injury as well as marked suppression of spermatogenesis, while the IV or IV+CV group showed no marked changes. The fertility test revealed that the male mice with IV+CV administration had normal fertility, and no malformations were detected in their progeny. This DDS model is of potential importance for clinical application in the therapy of metastatic osteosarcoma. PMID:25633802

  15. Development of tumor-specific caffeine-potentiated chemotherapy using a novel drug delivery system with Span 80 nano-vesicles

    PubMed Central

    NAKATA, HIROSHI; MIYAZAKI, TATSUHIKO; IWASAKI, TOMOYUKI; NAKAMURA, ATSUSHI; KIDANI, TERUKI; SAKAYAMA, KENSHI; MASUMOTO, JUNYA; MIURA, HIROMASA

    2015-01-01

    In recent years, chemotherapy with caffeine has manifested potently high efficacy against osteosarcoma, although adverse effects have been observed. Recently, we developed a novel drug delivery system (DDS) with nonionic vesicles prepared from Span 80 which have promising physicochemical properties as an attractive possible alternative to commonly used liposomes. Herein, we demonstrated that tumor-specific caffeine-potentiated chemotherapy for murine osteosarcoma administered by a novel DDS with Span 80 nano-vesicles showed significant antitumor effects as well as limited adverse effects. The osteosarcoma cell line, LM8, was transplanted into C3H/HeJ mice which then were administered therapeutic agents. Ifosfamide (IFO) was employed as well as caffeine as an enhancer. Span 80 vesicles containing IFO and/or caffeine were freshly prepared. On days 0, 2 and 4, different combinations of the agents were administered to mice: IFO alone (direct i.v.), IFO vesicles (IV), IV + caffeine, IV + caffeine vesicles (CV), PBS alone vesicles (PV), and PBS alone as negative control (PBS i.v.). Then, the mice were sacrificed on day 7. Antitumor effects of the reagents were also analyzed in vitro. Moreover, fertility examination was performed. In vitro, a combination of IV+CV showed significant induction of apoptosis in the early phase. Tumor volumes in the IV+CV group were significantly reduced compared with the other groups. Histological analyses showed that the IV and IV+CV groups had significantly lower viable tumor areas. The IFO direct i.v. group showed a certain grade of renal injury as well as marked suppression of spermatogenesis, while the IV or IV+CV group showed no marked changes. The fertility test revealed that the male mice with IV+CV administration had normal fertility, and no malformations were detected in their progeny. This DDS model is of potential importance for clinical application in the therapy of metastatic osteosarcoma. PMID:25633802

  16. Evaluation of the Reproductive and Developmental Risks of Caffeine

    PubMed Central

    Brent, Robert L; Christian, Mildred S; Diener, Robert M

    2011-01-01

    A risk analysis of in utero caffeine exposure is presented utilizing epidemiological studies and animal studies dealing with congenital malformation, pregnancy loss, and weight reduction. These effects are of interest to teratologists, because animal studies are useful in their evaluation. Many of the epidemiology studies did not evaluate the impact of the “pregnancy signal,” which identifies healthy pregnancies and permits investigators to identify subjects with low pregnancy risks. The spontaneous abortion epidemiology studies were inconsistent and the majority did not consider the confounding introduced by not considering the pregnancy signal. The animal studies do not support the concept that caffeine is an abortafacient for the wide range of human caffeine exposures. Almost all the congenital malformation epidemiology studies were negative. Animal pharmacokinetic studies indicate that the teratogenic plasma level of caffeine has to reach or exceed 60 µg/ml, which is not attainable from ingesting large amounts of caffeine in foods and beverages. No epidemiological study described the “caffeine teratogenic syndrome.” Six of the 17 recent epidemiology studies dealing with the risk of caffeine and fetal weight reduction were negative. Seven of the positive studies had growth reductions that were clinically insignificant and none of the studies cited the animal literature. Analysis of caffeine's reproductive toxicity considers reproducibility and plausibility of clinical, epidemiological, and animal data. Moderate or even high amounts of beverages and foods containing caffeine do not increase the risks of congenital malformations, miscarriage or growth retardation. Pharmacokinetic studies markedly improve the ability to perform the risk analyses. Birth Defects Res (Part B) 92:152–187, 2011. © 2011 Wiley-Liss, Inc. PMID:21370398

  17. Effect of caffeine on oxidative stress during maximum incremental exercise.

    PubMed

    Olcina, Guillermo J; Muñoz, Diego; Timón, Rafael; Caballero, M Jesús; Maynar, Juan I; Córdova, Alfredo; Maynar, Marcos

    2006-01-01

    Caffeine (1,3,7-trimethylxanthine) is an habitual substance present in a wide variety of beverages and in chocolate-based foods and it is also used as adjuvant in some drugs. The antioxidant ability of caffeine has been reported in contrast with its pro- oxidant effects derived from its action mechanism such as the systemic release of catecholamines. The aim of this work was to evaluate the effect of caffeine on exercise oxidative stress, measuring plasma vitamins A, E, C and malonaldehyde (MDA) as markers of non enzymatic antioxidant status and lipid peroxidation respectively. Twenty young males participated in a double blind (caffeine 5mg·kg- 1 body weight or placebo) cycling test until exhaustion. In the exercise test, where caffeine was ingested prior to the test, exercise time to exhaustion, maximum heart rate, and oxygen uptake significantly increased, whereas respiratory exchange ratio (RER) decreased. Vitamins A and E decreased with exercise and vitamin C and MDA increased after both the caffeine and placebo tests but, regarding these particular variables, there were no significant differences between the two test conditions. The results obtained support the conclusion that this dose of caffeine enhances the ergospirometric response to cycling and has no effect on lipid peroxidation or on the antioxidant vitamins A, E and C. Key PointsCaffeine ingestion may improve maximal aerobic performance in non trained men.Cellular oxidative damage is not altered by caffeine ingestion in maximal aerobic exercises.Antioxidant response to exercise, vitamins A, E and C, is not modified by caffeine action in maximal aerobic efforts. PMID:24357958

  18. Factors associated with caffeine consumption.

    PubMed

    Brice, Carolyn F; Smith, Andrew P

    2002-01-01

    The main aim of this research was to identify factors that were related to caffeine consumption. From this investigation it can be concluded that coffee is the main source of caffeine and that consumption varies with time of day. Individuals may be utilising the arousing effects of caffeine by consuming it at times when arousal is low for instance to counteract sleep inertia or a post-lunch dip in alertness. There is, however, very little evidence to suggest that psychological characteristics such as personality traits or psychosocial factors are important in influencing caffeine consumption, although smoking was found to be related to the amount of caffeine consumed. PMID:11820098

  19. Hidden in Plain Sight: How Ventral Line Markings in Chameleons May Enhance Camouflage.

    PubMed

    Resetarits, Emlyn J; Raxworthy, Christopher J

    2016-02-01

    Chameleons, lizards often synonymous with camouflage for their color-changing abilities, possess a variety of permanent coloration patterns whose evolutionary significance remains largely unknown. In this study, we explore the potential for white ventral line markings in species across the genus Chamaeleonidae to function as a camouflage pattern against diurnal predators. Diurnal behavioral field studies of the white-lined chameleon Furcifer viridis showed that individuals typically exposed ventral line markings during the characteristic ring-flip antipredator behavior in response to a predatory threat. These ventral line markings are largely inconspicuous in other postures. Comparative morphological analyses of 86 species found that there was a significant positive correlation between ventral line markings with arboreal habitat type, even when accounting for phylogeny. These results suggest that ventral line markings (and the ring-flip behavior) could act as a disruptive or mimetic coloration marking for arboreal chameleons against visual diurnal predators. Further work testing differential predation rates is necessary in order to verify the proposed function of these line markings. PMID:26807752

  20. Caffeine and Migraine

    MedlinePlus

    ... Google+ Follow us on Twitter Follow us on Facebook Follow us on YouTube Follow us on Pinterest Follow us on Instagram DONATE TODAY Caffeine and Migraine Abuse, Maltreatment, and PTSD and Their Relationship to Migraine Altitude, Acute Mountain Sickness and Headache ...

  1. Caffeine Reinforces Flavor Preference and Behavior in Moderate Users but Not in Low Caffeine Users

    ERIC Educational Resources Information Center

    Dack, Charlotte; Reed, Phil

    2009-01-01

    The study examined the role of caffeine consumption in caffeine reinforcement. Previous findings have shown that caffeine reinforced flavor preference in moderate caffeine consumers who are caffeine deprived. However, most of these studies have employed rating procedures only, and have not shown the effectiveness of caffeine to reinforce behaviors…

  2. Direct effects of caffeine on osteoblastic cells metabolism: the possible causal effect of caffeine on the formation of osteoporosis

    PubMed Central

    Tsuang, Yang-Hwei; Sun, Jui-Sheng; Chen, Li-Ting; Sun, Samuel Chung-Kai; Chen, San-Chi

    2006-01-01

    Background Caffeine consumption has been reported to decrease bone mineral density (BMD), increase the risk of hip fracture, and negatively influence calcium retention. In this study, we investigated the influence of caffeine on the osteoblasts behaviour. Method Osteoblasts derived from newborn Wistar-rat calvaria was used in this study. The effects of various concentrations of caffeine on bone cell activities were evaluated by using MTT assay. Alkaline phosphatase (ALP) staining, von Kossa staining and biochemical parameters including ALP, lactate dehydrogenase (LDH), prostaglandin E2 (PGE2) and total protein were performed at day 1, 3, and 7. DNA degradation analysis under the caffeine influence was also performed. Results and discussion The results showed that the viability of the osteoblasts, the formation of ALP positive staining colonies and mineralization nodules formation in the osteoblasts cultures decreased significantly in the presence of 10 mM caffeine. The intracellular LDH, ALP and PGE2 content decreased significantly, the LDH and PGE2 secreted into the medium increased significantly. The activation of an irreversible commitment to cell death by caffeine was clearly demonstrated by DNA ladder staining. Conclusion In summary, our results suggest that caffeine has potential deleterious effect on the osteoblasts viability, which may enhance the rate of osteoblasts apoptosis. PMID:17150127

  3. Pioneer factor interactions and unmethylated CpG dinucleotides mark silent tissue-specific enhancers in embryonic stem cells.

    PubMed

    Xu, Jian; Pope, Scott D; Jazirehi, Ali R; Attema, Joanne L; Papathanasiou, Peter; Watts, Jason A; Zaret, Kenneth S; Weissman, Irving L; Smale, Stephen T

    2007-07-24

    Recent studies have suggested that, in ES cells, inactive genes encoding early developmental regulators possess bivalent histone modification domains and are therefore poised for activation. However, bivalent domains were not observed at typical tissue-specific genes. Here, we show that windows of unmethylated CpG dinucleotides and putative pioneer factor interactions mark enhancers for at least some tissue-specific genes in ES cells. The unmethylated windows expand in cells that express the gene and contract, disappear, or remain unchanged in nonexpressing tissues. However, in ES cells, they do not always coincide with common histone modifications. Genomic footprinting and chromatin immunoprecipitation demonstrated that transcription factor binding underlies the unmethylated windows at enhancers for the Ptcra and Alb1 genes. After stable integration of premethylated Ptcra enhancer constructs into the ES cell genome, the unmethylated windows readily appeared. In contrast, the premethylated constructs remained fully methylated and silent after introduction into Ptcra-expressing thymocytes. These findings provide initial functional support for a model in which pioneer factor interactions in ES cells promote the assembly of a chromatin structure that is permissive for subsequent activation, and in which differentiated tissues lack the machinery required for gene activation when these ES cell marks are absent. The enhancer marks may therefore represent important features of the pluripotent state. PMID:17640912

  4. The perspective of caffeine and caffeine derived compounds in therapy.

    PubMed

    Pohanka, M

    2015-01-01

    Caffeine (1,3,7-trimethylxanthine) is a plant secondary metabolite with a significant impact on multiple processes and regulatory pathways in the body. Though major part of the population meets caffeine via coffee, tea or chocolate, it has also an important role in pharmacology and it is used as a supplementary substance in medicaments. Currently, the ability of caffeine to ameliorate some neurodegenerative disorders is proved in some studies. This review describes basic data about caffeine including toxicity, pharmacokinetics, biological mechanism of the action, and metabolism. Beside this, promising applications of caffeine, new medicaments and derivatives are discussed. Relevant papers and inventions are depicted in the manuscript. Caffeine is a pharmacologically promising substance that deserves big consideration in the current research and development. The compound has several reasons to be an object of scientific interest and to be used for pharmacology purposes. Despite an extensive research for a long time, no significantly negative effects on human health were proved hence caffeine can be considered as a completely safe compound. The recent data about amelioration of neurodegenerative and other disorders are promising and deserving more work on the issue. ARTICLE HIGHLIGHTS: Caffeine is a purine alkaloid from plants and it has a broad use in current pharmacology. Caffeine is a competitive antagonist of neurotransmitter adenosine on adenosine receptors. The substance is added as a supplementary to drugs and food.Besides interfering on adenosine receptors, caffeine interacts with acetylcholinesterase, monoamine oxidase, phosphodiesterase, ryanodine receptors and others.Current research is devoted to the role of caffeine in neurodegenerative diseases and immunity alteration. New chemical compounds based on caffeine moiety are prepared (Tab. 4, Fig. 6, Ref. 149). PMID:26435014

  5. Caffeinated forage tricks honeybees into increasing foraging and recruitment behaviors.

    PubMed

    Couvillon, Margaret J; Al Toufailia, Hasan; Butterfield, Thomas M; Schrell, Felix; Ratnieks, Francis L W; Schürch, Roger

    2015-11-01

    In pollination, plants provide food reward to pollinators who in turn enhance plant reproduction by transferring pollen, making the relationship largely cooperative; however, because the interests of plants and pollinators do not always align, there exists the potential for conflict, where it may benefit both to cheat the other [1, 2]. Plants may even resort to chemistry: caffeine, a naturally occurring, bitter-tasting, pharmacologically active secondary compound whose main purpose is to detract herbivores, is also found in lower concentrations in the nectar of some plants, even though nectar, unlike leaves, is made to be consumed by pollinators. [corrected]. A recent laboratory study showed that caffeine may lead to efficient and effective foraging by aiding honeybee memory of a learned olfactory association [4], suggesting that caffeine may enhance bee reward perception. However, without field data, the wider ecological significance of caffeinated nectar remains difficult to interpret. Here we demonstrate in the field that caffeine generates significant individual- and colony-level effects in free-flying worker honeybees. Compared to a control, a sucrose solution with field-realistic doses of caffeine caused honeybees to significantly increase their foraging frequency, waggle dancing probability and frequency, and persistency and specificity to the forage location, resulting in a quadrupling of colony-level recruitment. An agent-based model also demonstrates how caffeine-enhanced foraging may reduce honey storage. Overall, caffeine causes bees to overestimate forage quality, tempting the colony into sub-optimal foraging strategies, which makes the relationship between pollinator and plant less mutualistic and more exploitative. VIDEO ABSTRACT. PMID:26480843

  6. Effect of caffeine on physiological sleep tendency and ability to sustain wakefulness at night.

    PubMed

    Walsh, J K; Muehlbach, M J; Humm, T M; Dickins, Q S; Sugerman, J L; Schweitzer, P K

    1990-01-01

    Marked sleepiness occurs during typical night shift work hours and this reduced alertness is associated with marked performance deficits. The effect of caffeine (versus placebo) upon sleepiness at night was studied using objective measures of physiological sleep tendency and ability to sustain wakefulness. Both measures show caffeine to reduce sleepiness at a single dose roughly the equivalent of two to four cups of coffee. Despite impressive objective differences in alertness with caffeine, subjects did not consistently differentiate between drug conditions on subjective alertness assessments. The use of CNS stimulants to promote alertness during night shift hours should be considered, particularly for occupations for which alertness is critical. PMID:2349369

  7. Adolescent caffeine consumption and self-reported violence and conduct disorder.

    PubMed

    Kristjansson, Alfgeir L; Sigfusdottir, Inga Dora; Frost, Stephanie S; James, Jack E

    2013-07-01

    Caffeine is the most widely used psychoactive substance in the world and currently the only one legally available to children and adolescents. The sale and use of caffeinated beverages has increased markedly among adolescents during the last decade. However, research on caffeine use and behaviors among adolescents is scarce. We investigate the relationship between adolescent caffeine use and self-reported violent behaviors and conduct disorders in a population-based cross-sectional sample of 3,747 10th grade students (15-16 years of age, 50.2 % girls) who were enrolled in the Icelandic national education system during February 2012. Through a series of multiple regression models, while controlling for background factors, Attention Deficit Hyperactivity Disorder symptoms and current medication and peer delinquency, and including measures on substance use, our findings show robust additive explanatory power of caffeine for both violent behaviors and conduct disorders. In addition, the association of caffeine to the outcomes is significantly stronger for girls than boys for both violent behaviors and conduct disorders. Future studies are needed to examine to what extent, if at all, these relationships are causal. Indication of causal connections between caffeine consumption and negative outcomes such as those reported here would call into question the acceptability of current policies concerning the availability of caffeine to adolescents and the targeting of adolescence in the marketing of caffeine products. PMID:23358888

  8. Adolescent caffeine consumption increases adulthood anxiety-related behavior and modifies neuroendocrine signaling.

    PubMed

    O'Neill, Casey E; Newsom, Ryan J; Stafford, Jacob; Scott, Talia; Archuleta, Solana; Levis, Sophia C; Spencer, Robert L; Campeau, Serge; Bachtell, Ryan K

    2016-05-01

    Caffeine is a commonly used psychoactive substance and consumption by children and adolescents continues to rise. Here, we examine the lasting effects of adolescent caffeine consumption on anxiety-related behaviors and several neuroendocrine measures in adulthood. Adolescent male Sprague-Dawley rats consumed caffeine (0.3g/L) for 28 consecutive days from postnatal day 28 (P28) to P55. Age-matched control rats consumed water. Behavioral testing for anxiety-related behavior began in adulthood (P62) 7 days after removal of caffeine. Adolescent caffeine consumption enhanced anxiety-related behavior in an open field, social interaction test, and elevated plus maze. Similar caffeine consumption in adult rats did not alter anxiety-related behavior after caffeine removal. Characterization of neuroendocrine measures was next assessed to determine whether the changes in anxiety were associated with modifications in the HPA axis. Blood plasma levels of corticosterone (CORT) were assessed throughout the caffeine consumption procedure in adolescent rats. Adolescent caffeine consumption elevated plasma CORT 24h after initiation of caffeine consumption that normalized over the course of the 28-day consumption procedure. CORT levels were also elevated 24h after caffeine removal and remained elevated for 7 days. Despite elevated basal CORT in adult rats that consumed caffeine during adolescence, the adrenocorticotropic hormone (ACTH) and CORT response to placement on an elevated pedestal (a mild stressor) was significantly blunted. Lastly, we assessed changes in basal and stress-induced c-fos and corticotropin-releasing factor (Crf) mRNA expression in brain tissue collected at 7 days withdrawal from adolescent caffeine. Adolescent caffeine consumption increased basal c-fos mRNA in the paraventricular nucleus of the hypothalamus. Adolescent caffeine consumption had no other effects on the basal or stress-induced c-fos mRNA changes. Caffeine consumption during adolescence increased

  9. Acute caffeine treatment increases extracellular nucleotide hydrolysis from rat striatal and hippocampal synaptosomes.

    PubMed

    da Silva, Rosane Souza; Bruno, Alessandra Nejar; Battastini, Ana Maria Oliveira; Sarkis, João José Freitas; Lara, Diogo Rizzato; Bonan, Carla Denise

    2003-08-01

    The psychostimulant caffeine promotes behavioral effects such as hyperlocomotion, anxiety, and disruption of sleep by blockade of adenosine receptors. The availability of extracellular adenosine depends on its release by transporters or by the extracellular ATP catabolism performed by the ecto-nucleotidase pathway. This study verified the effect of caffeine on NTPDase 1 (ATP diphosphohydrolase) and 5'-nucleotidase of synaptosomes from hippocampus and striatum of rats. Caffeine and theophylline tested in vitro were unable to modify nucleotide hydrolysis. Caffeine chronically administered in the drinking water at 0.3 g/L or 1 g/L for 14 days failed to affect nucleotide hydrolysis. However, acute administration of caffeine (30 mg/kg, i.p.) produced an enhancement of ATP (50%) and ADP (32%) hydrolysis in synaptosomes of hippocampus and striatum, respectively. This activation of ATP and ADP hydrolysis after acute treatment suggests a compensatory effect to increase adenosine levels and counteract the antagonist action of caffeine. PMID:12834266

  10. Evaluating Dependence Criteria for Caffeine.

    PubMed

    Striley, Catherine L W; Griffiths, Roland R; Cottler, Linda B

    2011-12-01

    Background: Although caffeine is the most widely used mood-altering drug in the world, few studies have operationalized and characterized Diagnostic and Statistical Manual IV (DSM-IV) substance dependence criteria applied to caffeine. Methods: As a part of a nosological study of substance use disorders funded by the National Institute on Drug Abuse, we assessed caffeine use and dependence symptoms among high school and college students, drug treatment patients, and pain clinic patients who reported caffeine use in the last 7 days and also reported use of alcohol, nicotine, or illicit drugs within the past year (n=167). Results: Thirty-five percent met the criteria for dependence when all seven of the adopted DSM dependence criteria were used. Rates of endorsement of several of the most applicable diagnostic criteria were as follows: 26% withdrawal, 23% desire to cut down or control use, and 44% continued use despite harm. In addition, 34% endorsed craving, 26% said they needed caffeine to function, and 10% indicated that they talked to a physician or counselor about problems experienced with caffeine. There was a trend towards increased caffeine dependence among those dependent on nicotine or alcohol. Within a subgroup that had used caffeine, alcohol, and nicotine in the past year, 28% fulfilled criteria for caffeine dependence compared to 50% for alcohol and 80% for nicotine. Conclusion: The present study adds to a growing literature suggesting the reliability, validity, and clinical utility of the caffeine dependence diagnosis. Recognition of caffeine dependence in the DSM-V may be clinically useful. PMID:24761264

  11. A benefit-risk assessment of caffeine as an analgesic adjuvant.

    PubMed

    Zhang, W Y

    2001-01-01

    Caffeine has been an additive in analgesics for many years. However, the analgesic adjuvant effects of caffeine have not been seriously investigated since a pooled analysis conducted in 1984 showed that caffeine reduces the amount of paracetamol (acetaminophen) necessary for the same effect by approximately 40%. In vitro and in vivo pharmacological research has provided some evidence that caffeine can have anti-nociceptive actions through blockade of adenosine receptors, inhibition of cyclo-oxygenase-2 enzyme synthesis, or by changes in emotion state. Nevertheless, these actions are only considered in some cases. It is suggested that the actual doses of analgesics and caffeine used can influence the analgesic adjuvant effects of caffeine, and doses that are either too low or too high lead to no analgesic enhancement. Clinical trials suggest that caffeine in doses of more than 65 mg may be useful for enhancement of analgesia. However, except for in headache pain, the benefits are equivocal. While adding caffeine to analgesics increases the number of patients who become free from headache [rate ratio = 1.36, 95% confidence interval (CI) 1.17 to 1.58], it also leads to more patients with nervousness and dizziness (relative risk = 1.60, 95% CI 1.26 to 2.03). It is suggested that long-term use or overuse of analgesic medications is associated with rebound headache. However, there is no robust evidence that headache after use or withdrawal of caffeine-containing analgesics is more frequent than after other analgesics. Case-control studies have shown that caffeine-containing analgesics are associated with analgesic nephropathy (odds ratio = 4.9, 95% CI 2.3 to 10.3). However, no specific contribution of caffeine to analgesic nephropathy can be identified from these studies. Whether caffeine produces nephrotoxicity on its own, or increases nephrotoxicity due to analgesics, is yet to be established. PMID:11772146

  12. Two Enhanced Heuristic Algorithms for the Minimum Initial Marking Problem of Petri Nets

    NASA Astrophysics Data System (ADS)

    Ochiiwa, Satoru; Taoka, Satoshi; Yamauchi, Masahiro; Watanabe, Toshimasa

    The minimum initial marking problem of Petri nets (MIM) is defined as follows: “Given a Petri net and a firing count vector X, find an initial marking M0, with the minimum total token number, for which there is a sequence δ of transitions such that each transition t appears exactly X(t) times in δ, the first transition is enabled at M0 and the rest can be fired one by one subsequently.” In a production system like factory automation, economical distribution of initial resources, from which a schedule of job-processings is executable, can be formulated as MIM. AAD is known to produce best solutions among existing algorithms. Although solutions by AMIM+ is worse than those by AAD, it is known that AMIM+ is very fast. This paper proposes new heuristic algorithms AADO and AMDLO, improved versions of existing algorithms AAD and AMIM+, respectively. Sharpness of solutions or short CPU time is the main target of AADO or AMDLO, respectively. It is shown, based on computing experiment, that the average total number of tokens in initial markings by AADO is about 5.15% less than that by AAD, and the average CPU time by AADO is about 17.3% of that by AAD. AMDLO produces solutions that are slightly worse than those by AAD, while they are about 10.4% better than those by AMIM+. Although CPU time of AMDLO is about 180 times that of AMIM+, it is still fast: average CPU time of AMDLO is about 2.33% of that of AAD. Generally it is observed that solutions get worse as the sizes of input instances increase, and this is the case with AAD and AMIM+. This undesirable tendency is greatly improved in AADO and AMDLO.

  13. The Effects of Caffeine on Athletic Performance

    ERIC Educational Resources Information Center

    McDaniel, Larry W.; McIntire, Kyle; Streitz, Carmyn; Jackson, Allen; Gaudet, Laura

    2010-01-01

    Athletes who use caffeine before exercising or competition may be upgrading themselves more than they realize. Caffeine is classified as a stimulant and is the most commonly used drug in the world. Caffeine has the same affects that amphetamines and cocaine have, just to a lesser degree. Caffeine crosses the membranes of all the body's tissues. It…

  14. Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain

    PubMed Central

    Volkow, N D; Wang, G-J; Logan, J; Alexoff, D; Fowler, J S; Thanos, P K; Wong, C; Casado, V; Ferre, S; Tomasi, D

    2015-01-01

    Caffeine, the most widely consumed psychoactive substance in the world, is used to promote wakefulness and enhance alertness. Like other wake-promoting drugs (stimulants and modafinil), caffeine enhances dopamine (DA) signaling in the brain, which it does predominantly by antagonizing adenosine A2A receptors (A2AR). However, it is unclear if caffeine, at the doses consumed by humans, increases DA release or whether it modulates the functions of postsynaptic DA receptors through its interaction with adenosine receptors, which modulate them. We used positron emission tomography and [11C]raclopride (DA D2/D3 receptor radioligand sensitive to endogenous DA) to assess if caffeine increased DA release in striatum in 20 healthy controls. Caffeine (300 mg p.o.) significantly increased the availability of D2/D3 receptors in putamen and ventral striatum, but not in caudate, when compared with placebo. In addition, caffeine-induced increases in D2/D3 receptor availability in the ventral striatum were associated with caffeine-induced increases in alertness. Our findings indicate that in the human brain, caffeine, at doses typically consumed, increases the availability of DA D2/D3 receptors, which indicates that caffeine does not increase DA in the striatum for this would have decreased D2/D3 receptor availability. Instead, we interpret our findings to reflect an increase in D2/D3 receptor levels in striatum with caffeine (or changes in affinity). The association between increases in D2/D3 receptor availability in ventral striatum and alertness suggests that caffeine might enhance arousal, in part, by upregulating D2/D3 receptors. PMID:25871974

  15. Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain

    DOE PAGESBeta

    Volkow, N. D.; Wang, G. -J.; Logan, J.; Alexoff, D.; Fowler, J. S.; Thanos, P. K.; Wong, C.; Casado, V.; Ferre, S.; Tomasi, D.

    2015-04-14

    Caffeine, the most widely consumed psychoactive substance in the world, is used to promote wakefulness and enhance alertness. Like other wake-promoting drugs (stimulants and modafinil), caffeine enhances dopamine (DA) signaling in the brain, which it does predominantly by antagonizing adenosine A2A receptors (A2AR). However, it is unclear if caffeine, at the doses consumed by humans, increases DA release or whether it modulates the functions of postsynaptic DA receptors through its interaction with adenosine receptors, which modulate them. We used positron emission tomography and [11C]raclopride (DA D2/D3 receptor radioligand sensitive to endogenous DA) to assess if caffeine increased DA release inmore » striatum in 20 healthy controls. Caffeine (300mg p.o.) significantly increased the availability of D2/D3 receptors in putamen and ventral striatum, but not in caudate, when compared with placebo. In addition, caffeine-induced increases in D2/D3 receptor availability in the ventral striatum were associated with caffeine-induced increases in alertness. Our findings indicate that in the human brain, caffeine, at doses typically consumed, increases the availability of DA D2/D3 receptors, which indicates that caffeine does not increase DA in the striatum for this would have decreased D2/D3 receptor availability. Instead, we interpret our findings to reflect an increase in D2/D3 receptor levels in striatum with caffeine (or changes in affinity). Furthermore, the association between increases in D2/D3 receptor availability in ventral striatum and alertness suggests that caffeine might enhance arousal, in part, by upregulating D2/D3 receptors.« less

  16. Effect of caffeine on radiation-induced mitotic delay: delayed expression of G/sub 2/ arrest

    SciTech Connect

    Rowley, R.; Zorch, M.; Leeper, D.B.

    1984-01-01

    In the presence of 5 mM caffeine, irradiated (1.5 Gy) S and G/sub 2/ cells progressed to mitosis in register and without arrest in G/sub 2/. Caffeine (5 mM) markedly reduced mitotic delay even after radiation doses up to 20 Gy. When caffeine was removed from irradiated (1.5 Gy) and caffeine-treated cells, a period of G/sub 2/ arrest followed, similar in length to that produced by radiation alone. The arrest expressed was independent of the duration of the caffeine treatment for exposures up to 3 hr. The similarity of the response to the cited effects of caffeine on S-phase delay suggests a common basis for delay induction in S and G/sub 2/ phases.

  17. Caffeine provokes adverse interactions with 3,4-methylenedioxymethamphetamine (MDMA, ‘ecstasy’) and related psychostimulants: mechanisms and mediators

    PubMed Central

    Vanattou-Saïfoudine, N; McNamara, R; Harkin, A

    2012-01-01

    Concomitant consumption of caffeine with recreational psychostimulant drugs of abuse can provoke severe acute adverse reactions in addition to longer term consequences. The mechanisms by which caffeine increases the toxicity of psychostimulants include changes in body temperature regulation, cardiotoxicity and lowering of the seizure threshold. Caffeine also influences the stimulatory, discriminative and reinforcing effects of psychostimulant drugs. In this review, we consider our current understanding of such caffeine-related drug interactions, placing a particular emphasis on an adverse interaction between caffeine and the substituted amphetamine, 3,4-methylenedioxymethamphetamine (MDMA, ‘ecstasy’), which has been most recently described and characterized. Co-administration of caffeine profoundly enhances the acute toxicity of MDMA in rats, as manifested by high core body temperature, tachycardia and increased mortality. In addition, co-administration of caffeine enhances the long-term serotonergic neurotoxicity induced by MDMA. Observations to date support an interactive model of drug-induced toxicity comprising MDMA-related enhancement of dopamine release coupled to a caffeine-mediated antagonism of adenosine receptors in addition to inhibition of PDE. These experiments are reviewed together with reports of caffeine-related drug interactions with cocaine, d-amphetamine and ephedrine where similar mechanisms are implicated. Understanding the underlying mechanisms will guide appropriate intervention strategies for the management of severe reactions and potential for increased drug-related toxicity, resulting from concomitant caffeine consumption. PMID:22671762

  18. Effect of caffeine supplementation on haematological and biochemical variables in elite soccer players under physical stress conditions

    PubMed Central

    Bassini‐Cameron, Adriana; Sweet, Eric; Bottino, Altamiro; Bittar, Christina; Veiga, Carlos; Cameron, Luiz‐Claudio

    2007-01-01

    Objective To evaluate the effect of caffeine on white cell distribution and muscle injury markers in professional soccer players during exercise. Methods 22 male athletes completed a placebo controlled double blind test protocol to simulate a soccer match, followed by a Yo‐Yo intermittent recovery test. Results Exercise caused an increase in packed cell volume that was enhanced by caffeine. Caffeine and exercise had a synergistic effect on the blood lymphocyte count, which increased by about 38% after exercise, and by an additional 35% when combined with caffeine. Caffeine promoted an exercise independent rise in circulating monocytes, and a synergistic action of exercise and caffeine was observed on segmented neutrophils. Caffeine promoted thrombocytosis. Plasma adenosine deaminase, aspartate aminotransferase, and lactate dehydrogenase concentrations were enhanced by exercise, and alanine transaminase concentration was enhanced in both groups, with a synergistic effect of caffeine. Conclusions The pronounced increase in the white cell count in the group receiving caffeine appeared to be caused by greater muscle stress and consequently more intense endothelial and muscle cell injury. The use of caffeine may augment the risk of muscle damage in athletes. PMID:17473001

  19. Caffeine provokes adverse interactions with 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') and related psychostimulants: mechanisms and mediators.

    PubMed

    Vanattou-Saïfoudine, N; McNamara, R; Harkin, A

    2012-11-01

    Concomitant consumption of caffeine with recreational psychostimulant drugs of abuse can provoke severe acute adverse reactions in addition to longer term consequences. The mechanisms by which caffeine increases the toxicity of psychostimulants include changes in body temperature regulation, cardiotoxicity and lowering of the seizure threshold. Caffeine also influences the stimulatory, discriminative and reinforcing effects of psychostimulant drugs. In this review, we consider our current understanding of such caffeine-related drug interactions, placing a particular emphasis on an adverse interaction between caffeine and the substituted amphetamine, 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy'), which has been most recently described and characterized. Co-administration of caffeine profoundly enhances the acute toxicity of MDMA in rats, as manifested by high core body temperature, tachycardia and increased mortality. In addition, co-administration of caffeine enhances the long-term serotonergic neurotoxicity induced by MDMA. Observations to date support an interactive model of drug-induced toxicity comprising MDMA-related enhancement of dopamine release coupled to a caffeine-mediated antagonism of adenosine receptors in addition to inhibition of PDE. These experiments are reviewed together with reports of caffeine-related drug interactions with cocaine, d-amphetamine and ephedrine where similar mechanisms are implicated. Understanding the underlying mechanisms will guide appropriate intervention strategies for the management of severe reactions and potential for increased drug-related toxicity, resulting from concomitant caffeine consumption. PMID:22671762

  20. Consumption of dietary caffeine and coffee in physically active populations: physiological interactions.

    PubMed

    Tunnicliffe, Jasmine M; Erdman, Kelly Anne; Reimer, Raylene A; Lun, Victor; Shearer, Jane

    2008-12-01

    Caffeine is a proven ergogenic aid, increasing athletic performance, endurance, and mental chronometry at doses as low as 1-3 mg.kg-1. As coffee is a readily available and commonly ingested form of caffeine, the two are often equated. However, coffee also contains hundreds of other biologically active compounds, many of which are metabolically distinct from caffeine. The purpose of this review was to examine the prevalence of coffee and (or) caffeine consumption among elite Canadian athletes, and to delineate the effects of coffee and caffeine on physical activity, weight maintenance, performance, and metabolism. A total of 270 self-reported 3-day food records were examined for caffeine intake from athletes registered with Canadian Sport Centres in 2005 and 2006. Athletes ranged in age from 16-45 years, and competed in 38 different sports. Results showed that 30% of athletes ingested >1 mg.kg-1.day-1 from a variety of sources. Average daily intake was 0.85 +/- 13 mg.kg-1. Caffeine intake was not correlated with any 1 sport; the 10 highest caffeine users were athletes from 9 different sports, including skill, endurance, and power sports. No differences were noted for average caffeine ingestion between summer and winter sports. High caffeine intakes corresponded to coffee ingestion, with the 25 highest individual intakes (193-895 mg.day-1) from coffee drinkers. In summary, it can be concluded that the majority of high-level Canadian athletes consume dietary caffeine primarily in the form of coffee. However, levels consumed are insufficient to elicit performance enhancement. Potential detrimental effects of caffeine consumption on exercise performance include gastric upset, withdrawal, sleep disturbance, and interactions with other dietary supplements. PMID:19088792

  1. Efficacy of acute caffeine ingestion for short-term high-intensity exercise performance: a systematic review.

    PubMed

    Astorino, Todd A; Roberson, Daniel W

    2010-01-01

    Caffeine is the most widely used drug in the world, commonly ingested in coffee, tea, soda, and energy drinks. Its ability to enhance muscular work has been apparent since the early 1900s. Caffeine typically increases endurance performance; however, efficacy of caffeine ingestion for short-term high-intensity exercise is equivocal, which may be explained by discrepancies in exercise protocols, dosing, and subjects' training status and habitual caffeine intake found across studies. The primary aim of this review is to critically examine studies that have tested caffeine's ability to augment performance during exercise dependent on nonoxidative metabolism such as sprinting, team sports, and resistance training. A review of the literature revealed 29 studies that measured alterations in short-term performance after caffeine ingestion. Each study was critically analyzed using the Physiotherapy Evidence Database (PEDro) scale. The mean PEDro score was 7.76 +/- 0.87. Eleven of 17 studies revealed significant improvements in team sports exercise and power-based sports with caffeine ingestion, yet these effects were more common in elite athletes who do not regularly ingest caffeine. Six of 11 studies revealed significant benefits of caffeine for resistance training. Some studies show decreased performance with caffeine ingestion when repeated bouts are completed. The exact mechanism explaining the ergogenic effect of caffeine for short-term exercise is unknown. PMID:19924012

  2. Active thermography and post-processing image enhancement for recovering of abraded and paint-covered alphanumeric identification marks

    NASA Astrophysics Data System (ADS)

    Montanini, R.; Quattrocchi, A.; Piccolo, S. A.

    2016-09-01

    Alphanumeric marking is a common technique employed in industrial applications for identification of products. However, the realised mark can undergo deterioration, either by extensive use or voluntary deletion (e.g. removal of identification numbers of weapons or vehicles). For recovery of the lost data many destructive or non-destructive techniques have been endeavoured so far, which however present several restrictions. In this paper, active infrared thermography has been exploited for the first time in order to assess its effectiveness in restoring paint covered and abraded labels made by means of different manufacturing processes (laser, dot peen, impact, cold press and scribe). Optical excitation of the target surface has been achieved using pulse (PT), lock-in (LT) and step heating (SHT) thermography. Raw infrared images were analysed with a dedicated image processing software originally developed in Matlab™, exploiting several methods, which include thermographic signal reconstruction (TSR), guided filtering (GF), block guided filtering (BGF) and logarithmic transformation (LN). Proper image processing of the raw infrared images resulted in superior contrast and enhanced readability. In particular, for deeply abraded marks, good outcomes have been obtained by application of logarithmic transformation to raw PT images and block guided filtering to raw phase LT images. With PT and LT it was relatively easy to recover labels covered by paint, with the latter one providing better thermal contrast for all the examined targets. Step heating thermography never led to adequate label identification instead.

  3. Do energy drinks contain active components other than caffeine?

    PubMed

    McLellan, Tom M; Lieberman, Harris R

    2012-12-01

    Energy drinks (EDs) contain caffeine and are a new, popular category of beverage. It has been suggested that EDs enhance physical and cognitive performance; however, it is unclear whether the claimed benefits are attributable to components other than caffeine. A typical 235 mL ED provides between 40 and 250 mg of caffeine, equating to doses that improve cognitive and, at the higher levels, physical performance. EDs often contain taurine, guaraná, ginseng, glucuronolactone, B-vitamins, and other compounds. A literature search using PubMed, Psych Info, and Google Scholar identified 32 articles that examined the effects of ED ingredients alone and/or in combination with caffeine on physical or cognitive performance. A systematic evaluation of the evidence-based findings in these articles was then conducted. With the exception of some weak evidence for glucose and guaraná extract, there is an overwhelming lack of evidence to substantiate claims that components of EDs, other than caffeine, contribute to the enhancement of physical or cognitive performance. Additional well-designed, randomized, placebo-controlled studies replicated across laboratories are needed in order to assess claims made for these products. PMID:23206286

  4. Markedly enhanced absorption and direct radiative forcing of black carbon under polluted urban environments.

    PubMed

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Levy Zamora, Misti; Zeng, Limin; Shao, Min; Wu, Yu-Sheng; Zheng, Jun; Wang, Yuan; Glen, Crystal R; Collins, Donald R; Molina, Mario J; Zhang, Renyi

    2016-04-19

    Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China, and Houston, United States, using a novel environmental chamber approach. BC aging exhibits two distinct stages, i.e., initial transformation from a fractal to spherical morphology with little absorption variation and subsequent growth of fully compact particles with a large absorption enhancement. The timescales to achieve complete morphology modification and an absorption amplification factor of 2.4 for BC particles are estimated to be 2.3 h and 4.6 h, respectively, in Beijing, compared with 9 h and 18 h, respectively, in Houston. Our findings indicate that BC under polluted urban environments could play an essential role in pollution development and contribute importantly to large positive radiative forcing. The variation in direct radiative forcing is dependent on the rate and timescale of BC aging, with a clear distinction between urban cities in developed and developing countries, i.e., a higher climatic impact in more polluted environments. We suggest that mediation in BC emissions achieves a cobenefit in simultaneously controlling air pollution and protecting climate, especially for developing countries. PMID:27035993

  5. Markedly enhanced absorption and direct radiative forcing of black carbon under polluted urban environments

    PubMed Central

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Levy Zamora, Misti; Zeng, Limin; Shao, Min; Wu, Yu-Sheng; Zheng, Jun; Wang, Yuan; Glen, Crystal R.; Collins, Donald R.; Molina, Mario J.; Zhang, Renyi

    2016-01-01

    Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China, and Houston, United States, using a novel environmental chamber approach. BC aging exhibits two distinct stages, i.e., initial transformation from a fractal to spherical morphology with little absorption variation and subsequent growth of fully compact particles with a large absorption enhancement. The timescales to achieve complete morphology modification and an absorption amplification factor of 2.4 for BC particles are estimated to be 2.3 h and 4.6 h, respectively, in Beijing, compared with 9 h and 18 h, respectively, in Houston. Our findings indicate that BC under polluted urban environments could play an essential role in pollution development and contribute importantly to large positive radiative forcing. The variation in direct radiative forcing is dependent on the rate and timescale of BC aging, with a clear distinction between urban cities in developed and developing countries, i.e., a higher climatic impact in more polluted environments. We suggest that mediation in BC emissions achieves a cobenefit in simultaneously controlling air pollution and protecting climate, especially for developing countries. PMID:27035993

  6. Markedly enhanced absorption and direct radiative forcing of black carbon under polluted urban environments

    NASA Astrophysics Data System (ADS)

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Levy Zamora, Misti; Zeng, Limin; Shao, Min; Wu, Yu-Sheng; Zheng, Jun; Wang, Yuan; Glen, Crystal R.; Collins, Donald R.; Molina, Mario J.

    2016-04-01

    Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China, and Houston, United States, using a novel environmental chamber approach. BC aging exhibits two distinct stages, i.e., initial transformation from a fractal to spherical morphology with little absorption variation and subsequent growth of fully compact particles with a large absorption enhancement. The timescales to achieve complete morphology modification and an absorption amplification factor of 2.4 for BC particles are estimated to be 2.3 h and 4.6 h, respectively, in Beijing, compared with 9 h and 18 h, respectively, in Houston. Our findings indicate that BC under polluted urban environments could play an essential role in pollution development and contribute importantly to large positive radiative forcing. The variation in direct radiative forcing is dependent on the rate and timescale of BC aging, with a clear distinction between urban cities in developed and developing countries, i.e., a higher climatic impact in more polluted environments. We suggest that mediation in BC emissions achieves a cobenefit in simultaneously controlling air pollution and protecting climate, especially for developing countries.

  7. Markedly enhanced direct radiative forcing of black carbon particles under polluted urban environments

    NASA Astrophysics Data System (ADS)

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Zamora, Misti; Zeng, Liming; Shao, Min; Wu, Yusheng; Zheng, Jun; Wang, Yuan; Collins, Don; Zhang, Renyi

    2016-04-01

    Black carbon (BC) particles, produced from incomplete fossil fuel combustion and biomass burning, are ubiquitous in the atmosphere and have profound impacts on air quality, human health, weather, and climate. For example, in areas identified as aerosol hotspots, which include many urban centers and megacities worldwide, solar heating by BC particles has been shown to be comparable to warming due to the greenhouse gases2. Although BC represents a key short-lived climate forcer, its direct radiative forcing remains highly uncertain. In particular, the available results of absorption enhancement of BC particles during atmospheric aging are conflicting from the previous studies, leading to a large uncertainty in global radiative transfer calculation. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China and Houston, US, using a novel chamber approach. BC aging exhibits two distinct stages - initial transformation from a fractal to spherical morphology with little absorption variation and the subsequent growth of fully compact particles with a maximum absorption enhancement factor of 2.4. The variation in BC direct radiative forcing is highly dependent of the rate and timescale of aging, with an estimated increase of 0.45 (0.21 - 0.80) W m-2 from fresh to fully aged particles. Our results reveal a high climatic impact in polluted environments due to rapid aging and a clear distinction between urban cities in developed and developing countries for BC particles, highlighting a larger than recognized co-benefit in air quality improvement and climate protection by BC mediation.

  8. Caffeine's Vascular Mechanisms of Action

    PubMed Central

    Echeverri, Darío; Montes, Félix R.; Cabrera, Mariana; Galán, Angélica; Prieto, Angélica

    2010-01-01

    Caffeine is the most widely consumed stimulating substance in the world. It is found in coffee, tea, soft drinks, chocolate, and many medications. Caffeine is a xanthine with various effects and mechanisms of action in vascular tissue. In endothelial cells, it increases intracellular calcium stimulating the production of nitric oxide through the expression of the endothelial nitric oxide synthase enzyme. Nitric oxide is diffused to the vascular smooth muscle cell to produce vasodilation. In vascular smooth muscle cells its effect is predominantly a competitive inhibition of phosphodiesterase, producing an accumulation of cAMP and vasodilation. In addition, it blocks the adenosine receptors present in the vascular tissue to produce vasoconstriction. In this paper the main mechanisms of action of caffeine on the vascular tissue are described, in which it is shown that caffeine has some cardiovascular properties and effects which could be considered beneficial. PMID:21188209

  9. Configuring retroreflective markings to enhance the night-time conspicuity of road workers.

    PubMed

    Wood, Joanne M; Marszalek, Ralph; Lacherez, Philippe; Tyrrell, Richard A

    2014-09-01

    This study investigated whether the night-time conspicuity of road workers can be enhanced by positioning retroreflective strips on the moveable joints in patterns that convey varying degrees of biological motion. Participants were 24 visually normal adults (12 young M=26.8 years; 12 older M=72.9 years). Visual acuity, contrast sensitivity and glare sensitivity were recorded for each participant. Experimenters acting as road workers walked in place on a closed road circuit within simulated road work sites, facing either the oncoming driver or the roadway (presenting sideways to the driver) and wearing one of four clothing conditions: (i) standard road worker vest; (ii) standard vest plus thigh-mounted retroreflective strips; (iii) standard vest plus retroreflective strips on ankles and knees; (iv) standard vest plus retroreflective strips positioned on the extremities in a configuration that conveyed biological motion ("biomotion"). As they drove along the closed road participants were instructed to press a button to indicate when they first recognized that a road worker was present. The results demonstrated that regardless of the direction of walking, road workers wearing biomotion clothing were recognized at significantly (p<0.05) longer distances (3×), relative to the standard vest alone. Response distances were significantly shorter for the older drivers. Contrast sensitivity was a better predictor of the ability to recognize road workers than was visual acuity or glare sensitivity. We conclude that adding retroreflective strips in the biomotion configuration can significantly improve road worker conspicuity regardless of the road worker's orientation and the age of the driver. PMID:24816151

  10. Maleimide conjugation markedly enhances the immunogenicity of both human and murine idiotype-KLH vaccines

    PubMed Central

    Kafi, Kamran; Betting, David J.; Yamada, Reiko E.; Bacica, Michael; Steward, Kristopher K.; Timmerman, John M.

    2009-01-01

    The collection of epitopes present within the variable regions of the tumor-specific clonal immunoglobulin expressed by B cell lymphomas (idiotype, Id) can serve as a target for active immunotherapy. Traditionally, tumor-derived Id protein is chemically-conjugated to the immunogenic foreign carrier protein keyhole limpet hemocyanin (KLH) using glutaraldehyde to serve as a therapeutic vaccine. While this approach offered promising results for some patients treated in early clinical trials, glutaraldehyde Id-KLH vaccines have failed to induce immune and clinical responses in many vaccinated subjects. We recently described an alternative conjugation method employing maleimide-sulfhydryl chemistry that significantly increased the therapeutic efficacy of Id-KLH vaccines in three different murine B cell lymphoma models, with protection mediated by either CD8+ T cells or antibodies. We now define in detail the methods and parameters critical for enhancing the in vivo immunogenicity of human as well as murine Id-KLH conjugate vaccines. Optimal conditions for Id sulfhydryl pre-reduction were determined, and maleimide Id-KLH conjugates maintained stability and potency even after prolonged storage. Field flow fractionation analysis of Id-KLH particle size revealed that maleimide conjugates were far more uniform in size than glutaraldehyde conjugates. Under increasingly stringent conditions, maleimide Id-KLH vaccines maintained superior efficacy over glutaraldehyde Id-KLH in treating established, disseminated murine lymphoma. More importantly, human maleimide Id-KLH conjugates were consistently superior to glutaraldehyde Id-KLH conjugates in inducing Id-specific antibody and T cell responses. The described methods should be easily adaptable to the production of clinical grade vaccines for human trials in B cell malignancies. PMID:19046770

  11. Maleimide conjugation markedly enhances the immunogenicity of both human and murine idiotype-KLH vaccines.

    PubMed

    Kafi, Kamran; Betting, David J; Yamada, Reiko E; Bacica, Michael; Steward, Kristopher K; Timmerman, John M

    2009-01-01

    The collection of epitopes present within the variable regions of the tumor-specific clonal immunoglobulin expressed by B cell lymphomas (idiotype, Id) can serve as a target for active immunotherapy. Traditionally, tumor-derived Id protein is chemically conjugated to the immunogenic foreign carrier protein keyhole limpet hemocyanin (KLH) using glutaraldehyde to serve as a therapeutic vaccine. While this approach offered promising results for some patients treated in early clinical trials, glutaraldehyde Id-KLH vaccines have failed to induce immune and clinical responses in many vaccinated subjects. We recently described an alternative conjugation method employing maleimide-sulfhydryl chemistry that significantly increased the therapeutic efficacy of Id-KLH vaccines in three different murine B cell lymphoma models, with protection mediated by either CD8(+) T cells or antibodies. We now define in detail the methods and parameters critical for enhancing the in vivo immunogenicity of human as well as murine Id-KLH conjugate vaccines. Optimal conditions for Id sulfhydryl pre-reduction were determined, and maleimide Id-KLH conjugates maintained stability and potency even after prolonged storage. Field flow fractionation analysis of Id-KLH particle size revealed that maleimide conjugates were far more uniform in size than glutaraldehyde conjugates. Under increasingly stringent conditions, maleimide Id-KLH vaccines maintained superior efficacy over glutaraldehyde Id-KLH in treating established, disseminated murine lymphoma. More importantly, human maleimide Id-KLH conjugates were consistently superior to glutaraldehyde Id-KLH conjugates in inducing Id-specific antibody and T cell responses. The described methods should be easily adaptable to the production of clinical grade vaccines for human trials in B cell malignancies. PMID:19046770

  12. Nicotine Deprivation Produces Deficits in Pain Perception that are Moderately Attenuated by Caffeine Consumption.

    PubMed

    Baiamonte, Brandon A; Stickley, Sarah C; Ford, Sarah J

    2016-01-01

    During withdrawal, nicotine users experience aversive withdrawal symptoms, such as increased nociceptive processing, which may be responsible for subsequent use. Smokers often consume more caffeine than non-smokers and the combined effects of these two psychoactive drugs result in an enhanced analgesic effect of nicotine. We examined the effects of caffeine (via coffee consumption) and nicotine withdrawal on pain perception in minimally deprived smokers and non-smokers. Pain threshold and pain tolerance were assessed using a radiant heat stimulus before and 30 minutes after caffeine consumption. Nicotine deprivation (2 hrs) produced increases in pain threshold and decreases in pain tolerance representative of hyperalgesia. When smokers are nicotine deprived, caffeine consumption diminished baseline elevations in pain threshold, but had no effect on pain tolerance. These data suggest that caffeine consumption can dampen deficits in sensory discrimination related to pain during nicotine deprivation by reducing pain threshold to levels representative of non-smoking controls. PMID:27120004

  13. Markedly Enhanced Skeletal Muscle Transfection Achieved by the Ultrasound-Targeted Delivery of Non-Viral Gene Nanocarriers with Microbubbles

    PubMed Central

    Burke, Caitlin W.; Suk, Jung Soo; Kim, Anthony J.; Hsiang, Yu-Han J.; Klibanov, Alexander L.; Hanes, Justin; Price, Richard J.

    2012-01-01

    Our goal was to enhance ultrasound (US)-targeted skeletal muscle transfection through the use of poly(ethyleneglycol) (PEG)/polyethylenimine (PEI) nanocomplex gene carriers and adjustments to US and microbubble (MB) parameters. C57BL/6 mice received an intravenous infusion of MBs and either “naked” luciferase plasmid or luciferase plasmid condensed in PEG/PEI nanocomplexes. Pulsed ultrasound (1MHz; 0.6 MPa or 0.8 MPa) was applied to the right hindlimb for 12 mins. Luciferase activity in both hindlimbs was assessed at 3, 5, 7, and 10 days post-treatment by bioluminescent imaging. When targeted to hindlimb using unsorted MBs and 0.6 MPa US, 7 days after treatment, we observed a >60-fold increase in luciferase activity in PEG/PEI nanocomplex treated muscles over muscles treated with “naked” plasmid DNA. Luciferase activity was consistently greater after treatment with PEG/PEI nanocomplexes at 0.6 MPa as compared to 0.8 MPa. The combination of small diameter MBs and 0.6 MPa US also resulted in significantly greater gene expression when compared to concentration matched intramuscular injections, a control condition in which considerably more PEG/PEI nanocomplexes were present in tissue. This result suggests that, in addition to facilitating PEG/PEI nanocomplex delivery from the bloodstream to tissue, US enhances transfection via one or more secondary mechanisms, including increased cellular uptake and/or trafficking to the nucleus of PEG/PEI nanocomplexes. We conclude that PEG/PEI nanocomplexes may be used to markedly enhance the amplitude of US-MB-targeted skeletal muscle transfection and that activating “small” MBs with a moderate level (0.6 MPa) of acoustic pressure can further enhance these effects. PMID:22800583

  14. Effects of dilute aqueous NaCl solution on caffeine aggregation

    SciTech Connect

    Sharma, Bhanita; Paul, Sandip

    2013-11-21

    The effect of salt concentration on association properties of caffeine molecule was investigated by employing molecular dynamics simulations in isothermal-isobaric ensemble of eight caffeine molecules in pure water and three different salt (NaCl) concentrations, at 300 K temperature and 1 atm pressure. The concentration of caffeine was taken almost at the solubility limit. With increasing salt concentration, we observe enhancement of first peak height and appearance of a second peak in the caffeine-caffeine distribution function. Furthermore, our calculated solvent accessible area values and cluster structure analyses suggest formation of higher order caffeine cluster on addition of salt. The calculated hydrogen bond properties reveal that there is a modest decrease in the average number of water-caffeine hydrogen bonds on addition of NaCl salt. Also observed are: (i) decrease in probability of salt contact ion pair as well as decrease in the solvent separated ion pair formation with increasing salt concentration, (ii) a modest second shell collapse in the water structure, and (iii) dehydration of hydrophobic atomic sites of caffeine on addition of NaCl.

  15. Effects of dilute aqueous NaCl solution on caffeine aggregation

    NASA Astrophysics Data System (ADS)

    Sharma, Bhanita; Paul, Sandip

    2013-11-01

    The effect of salt concentration on association properties of caffeine molecule was investigated by employing molecular dynamics simulations in isothermal-isobaric ensemble of eight caffeine molecules in pure water and three different salt (NaCl) concentrations, at 300 K temperature and 1 atm pressure. The concentration of caffeine was taken almost at the solubility limit. With increasing salt concentration, we observe enhancement of first peak height and appearance of a second peak in the caffeine-caffeine distribution function. Furthermore, our calculated solvent accessible area values and cluster structure analyses suggest formation of higher order caffeine cluster on addition of salt. The calculated hydrogen bond properties reveal that there is a modest decrease in the average number of water-caffeine hydrogen bonds on addition of NaCl salt. Also observed are: (i) decrease in probability of salt contact ion pair as well as decrease in the solvent separated ion pair formation with increasing salt concentration, (ii) a modest second shell collapse in the water structure, and (iii) dehydration of hydrophobic atomic sites of caffeine on addition of NaCl.

  16. Discriminative Stimulus Effects of Binary Drug Mixtures: Studies with Cocaine, MDPV, and Caffeine.

    PubMed

    Collins, Gregory T; Abbott, Megan; Galindo, Kayla; Rush, Elise L; Rice, Kenner C; France, Charles P

    2016-10-01

    Illicit drug preparations often include more than one pharmacologically active compound. For example, cocaine and synthetic cathinones [e.g., 3,4-methylenedioxypyrovalerone (MDPV)] are often mixed with caffeine before sale. Caffeine is likely added to these preparations because it is inexpensive and legal; however, caffeine might also mimic or enhance some of the effects of cocaine or MDPV. In these studies, male Sprague-Dawley rats were trained to discriminate 10 mg/kg cocaine from saline, and the discriminative stimulus effects of cocaine, caffeine, and MDPV were evaluated alone and as binary mixtures (cocaine and caffeine, MDPV and caffeine, and cocaine and MDPV) at fixed-dose ratios of 3:1, 1:1, and 1:3 relative to the dose of each drug that produced 50% cocaine-appropriate responding. Dose-addition analyses were used to determine the nature of the drug-drug interactions for each mixture (e.g., additive, supra-additive, or subadditive). Although additive interactions were observed for most mixtures, supra-additive interactions were observed at the 50% effect level for the 1:1 mixture of cocaine and caffeine and at the 80% effect level for all three mixtures of cocaine and caffeine, as well as for the 3:1 and 1:3 mixtures of cocaine and MDPV. These results demonstrate that with respect to cocaine-like discriminative stimulus effects, caffeine can function as a substitute in drug preparations containing either cocaine or MDPV, with enhancements of cocaine-like effects possible under certain conditions. Further research is needed to determine whether similar interactions exist for other abuse-related or toxic effects of drug preparations, including cocaine, synthetic cathinones, and caffeine. PMID:27493274

  17. Caffeine content of beverages as consumed.

    PubMed Central

    Gilbert, R. M.; Marshman, J. A.; Schwieder, M.; Berg, R.

    1976-01-01

    Quantitative analysis of beverages prepared at home by staff of the Addiction Research Foundation revealed a lower and much more variable caffeine content of both tea and coffee than had been reported in earlier studies, most of which were based on analysis of laboratory-prepared beverages. Median caffeine concentration of 37 home-prepared samples of tea was 27 mg per cup (range, 8 to 91 mg); for 46 coffee samples the median concentration was 74 mg per cup (range, 29 to 176 mg). If tea and coffee as drunk contain less caffeine than generally supposed, the potency of caffeine may be greater than commonly realized, as may the relative caffeine content of certain commercial preparations, including chocolate and colas. The substantial variation in caffeine content emphasizes the need to establish actual caffeine intake in clinical, epidemiologic and experimental investigations of caffeine effects. PMID:1032351

  18. Caffeine Intake Among Adolescents in Delhi

    PubMed Central

    Gera, Mridul; Kalra, Swati; Gupta, Piyush

    2016-01-01

    Background: Availability and advertising of caffeinated drinks is on the rise in Indian market. Excess caffeine intake may have deleterious effects on health. Objective: To estimate the daily consumption of caffeine among urban school-going adolescents from Delhi. Materials and Methods: A school-based survey was conducted to determine the amount and pattern of caffeine consumption among students of classes 9-12, using a self-administered questionnaire. Results: Of 300 participants (median age 15 year, 174 boys), 291 (97%) were consuming caffeine [mean (SD): 121.0 (98.2) mg/day]. Nineteen (6%) students were consuming more than 300 mg of caffeine per day. Tea/coffee contributed to more than 50% of the caffeine intake. The rest was derived from cola beverages, chocolates, and energy drinks. Conclusion: Average caffeine consumption among school-going adolescents from Delhi is high. The findings of this preliminary survey need to be confirmed in larger data sets. PMID:27051091

  19. Effects of acute caffeine administration on adolescents.

    PubMed

    Temple, Jennifer L; Dewey, Amber M; Briatico, Laura N

    2010-12-01

    Acute caffeine administration has physiological, behavioral, and subjective effects. Despite its widespread use, few studies have described the impact of caffeine consumption in children and adolescents. The purpose of this study was to investigate the effects of acute caffeine administration in adolescents. We measured cardiovascular responses and snack food intake after acute administration of 0 mg, 50 mg, 100 mg, and 200 mg of caffeine. We also compared usual food intake and subjective effects of caffeine between high- and low-caffeine consumers. Finally, we conducted a detailed analysis of caffeine sources and consumption levels. We found main effects of caffeine dose on heart rate (HR) and diastolic blood pressure (DBP), with HR decreasing and DBP increasing with increasing caffeine dose. There were significant interactions among gender, caffeine use, and time on DBP. High caffeine consumers (>50 mg/day) reported using caffeine to stay awake and drinking coffee, tea, soda, and energy drinks more than low consumers (<50 mg/day). Boys were more likely than girls to report using getting a rush, more energy, or improved athletic performance from caffeine. Finally, when we examined energy and macronutrient intake, we found that caffeine consumption was positively associated with laboratory energy intake, specifically from high-sugar, low-fat foods and also positively associated with protein and fat consumption outside of the laboratory. When taken together, these data suggest that acute caffeine administration has a broad range of effects in adolescents and that the magnitude of these effects is moderated by gender and chronic caffeine consumption. PMID:21186925

  20. Development of a biosensor for caffeine.

    PubMed

    Babu, V R Sarath; Patra, S; Karanth, N G; Kumar, M A; Thakur, M S

    2007-01-23

    We have utilized a microbe, which can degrade caffeine to develop an Amperometric biosensor for determination of caffeine in solutions. Whole cells of Pseudomonas alcaligenes MTCC 5264 having the capability to degrade caffeine were immobilized on a cellophane membrane with a molecular weight cut off (MWCO) of 3000-6000 by covalent crosslinking method using glutaraledhyde as the bifunctional crosslinking agent and gelatin as the protein based stabilizing agent (PBSA). The biosensor system was able to detect caffeine in solution over a concentration range of 0.1 to 1 mg mL(-1). With read-times as short as 3 min, this caffeine biosensor acts as a rapid analysis system for caffeine in solutions. Interestingly, successful isolation and immobilization of caffeine degrading bacteria for the analysis of caffeine described here was enabled by a novel selection strategy that incorporated isolation of caffeine degrading bacteria capable of utilizing caffeine as the sole source of carbon and nitrogen from soils and induction of caffeine degrading capacity in bacteria for the development of the biosensor. This biosensor is highly specific for caffeine and response to interfering compounds such as theophylline, theobromine, paraxanthine, other methyl xanthines and sugars was found to be negligible. Although a few biosensing methods for caffeine are reported, they have limitations in application for commercial samples. The development and application of new caffeine detection methods remains an active area of investigation, particularly in food and clinical chemistry. The optimum pH and temperature of measurement were 6.8 and 30+/-2 degrees C, respectively. Interference in analysis of caffeine due to different substrates was observed but was not considerable. Caffeine content of commercial samples of instant tea and coffee was analyzed by the biosensor and the results compared well with HPLC analysis. PMID:17386510

  1. Caffeine Use and Young Adult Women.

    ERIC Educational Resources Information Center

    Vener, Arthur M.; Krupka, Lawrence R.

    1982-01-01

    Surveyed college women and men and found that caffeine was consumed by a large proportion of the respondents. Women consumed a larger amount of caffeine and used more substances containing this drug. An increase in caffeine usage with increased psychic stress was observed for women only. (Author)

  2. 21 CFR 182.1180 - Caffeine.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Caffeine. 182.1180 Section 182.1180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN....1180 Caffeine. (a) Product. Caffeine. (b) Tolerance. 0.02 percent. (c) Limitations, restrictions,...

  3. 21 CFR 182.1180 - Caffeine.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Caffeine. 182.1180 Section 182.1180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN....1180 Caffeine. (a) Product. Caffeine. (b) Tolerance. 0.02 percent. (c) Limitations, restrictions,...

  4. 21 CFR 182.1180 - Caffeine.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Caffeine. 182.1180 Section 182.1180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN....1180 Caffeine. (a) Product. Caffeine. (b) Tolerance. 0.02 percent. (c) Limitations, restrictions,...

  5. 21 CFR 182.1180 - Caffeine.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Caffeine. 182.1180 Section 182.1180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN....1180 Caffeine. (a) Product. Caffeine. (b) Tolerance. 0.02 percent. (c) Limitations, restrictions,...

  6. 21 CFR 182.1180 - Caffeine.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Caffeine. 182.1180 Section 182.1180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1180 Caffeine. (a) Product. Caffeine....

  7. The Effects of Caffeine on Vertical Jump Height and Execution in Collegiate Athletes.

    PubMed

    Bloms, Lucas P; Fitzgerald, John S; Short, Martin W; Whitehead, James R

    2016-07-01

    Bloms, LP, Fitzgerald, JS, Short, MW, and Whitehead, JR. The effects of caffeine on vertical jump height and execution in collegiate athletes. J Strength Cond Res 30(7): 1855-1861, 2016-Caffeine ingestion elicits a variety of physiological effects that may be beneficial to maximal-intensity exercise performance, although its effectiveness and physical mechanism of action enhancing ballistic task performance are unclear. The purpose of this study was to examine the effects of caffeine ingestion on vertical jump height and jump execution in Division I collegiate athletes. The study used a single-blind, randomized, crossover design. Athletes (n = 25) consumed either caffeine (5 mg·kg) or placebo. After a 60-minute waiting period, athletes performed 3 squat jumps (SJ) and 3 countermovement jumps (CMJ) while standing on a force platform. Jump height and execution variables were calculated from mechanography data. In comparison with placebo, caffeine increased SJ height (32.8 ± 6.2 vs. 34.5 ± 6.7 cm; p = 0.001) and CMJ height (36.4 ± 6.9 vs. 37.9 ± 7.4 cm; p = 0.001). Peak force (p = 0.032) and average rate of force development (p = 0.037) were increased during the CMJ in the caffeine trail compared with the control. Time to half peak force was the only execution variable improved with caffeine (p = 0.019) during the SJ. It seems that caffeine affects both height and execution of jumping. Our data indicate that the physical mechanism of jump enhancement is increased peak force production or rate of force development during jumping depending on technique. The physical mechanism of jump enhancement suggests that the ergogenic effects of caffeine may transfer to other ballistic tasks involving the lower-body musculature in collegiate athletes. PMID:26626028

  8. A Comparison of Blue Light and Caffeine Effects on Cognitive Function and Alertness in Humans

    PubMed Central

    Beaven, C. Martyn; Ekström, Johan

    2013-01-01

    The alerting effects of both caffeine and short wavelength (blue) light have been consistently reported. The ability of blue light to enhance alertness and cognitive function via non-image forming neuropathways have been suggested as a non-pharmacological countermeasure for drowsiness across a range of occupational settings. Here we compare and contrast the alerting and psychomotor effects of 240 mg of caffeine and a 1-h dose of ~40 lx blue light in a non-athletic population. Twenty-one healthy subjects performed a computer-based psychomotor vigilance test before and after each of four randomly assigned trial conditions performed on different days: white light/placebo; white light/240 mg caffeine; blue light/placebo; blue light/240 mg caffeine. The Karolinska Sleepiness Scale was used to assess subjective measures of alertness. Both the caffeine only and blue light only conditions enhanced accuracy in a visual reaction test requiring a decision and an additive effect was observed with respect to the fastest reaction times. However, in a test of executive function, where a distraction was included, caffeine exerted a negative effect on accuracy. Furthermore, the blue light only condition consistently outperformed caffeine when both congruent and incongruent distractions were presented. The visual reactions in the absence of a decision or distraction were also enhanced in the blue light only condition and this effect was most prominent in the blue-eyed participants. Overall, blue light and caffeine demonstrated distinct effects on aspects of psychomotor function and have the potential to positively influence a range of settings where cognitive function and alertness are important. Specifically, despite the widespread use of caffeine in competitive sporting environments, the possible impact of blue light has received no research attention. PMID:24282477

  9. The Effects of Preexercise Caffeinated Coffee Ingestion on Endurance Performance: An Evidence-Based Review.

    PubMed

    Higgins, Simon; Straight, Chad R; Lewis, Richard D

    2016-06-01

    Endurance athletes commonly ingest caffeine as a means to enhance training intensity and competitive performance. A widely-used source of caffeine is coffee, however conflicting evidence exists regarding the efficacy of coffee in improving endurance performance. In this context, the aims of this evidence-based review were threefold: 1) to evaluate the effects of preexercise coffee on endurance performance, 2) to evaluate the effects of coffee on perceived exertion during endurance performance, and 3) to translate the research into usable information for athletes to make an informed decision regarding the intake of caffeine via coffee as a potential ergogenic aid. Searches of three major databases were performed using terms caffeine and coffee, or coffee-caffeine, and endurance, or aerobic. Included studies (n = 9) evaluated the effects of caffeinated coffee on human subjects, provided the caffeine dose administered, administered caffeine ≥ 45 min before testing, and included a measure of endurance performance (e.g., time trial). Significant improvements in endurance performance were observed in five of nine studies, which were on average 24.2% over controls for time to exhaustion trials, and 3.1% for time to completion trials. Three of six studies found that coffee reduced perceived exertion during performance measures significantly more than control conditions (p < .05). Based on the reviewed studies there is moderate evidence supporting the use of coffee as an ergogenic aid to improve performance in endurance cycling and running. Coffee providing 3-8.1 mg/kg (1.36-3.68 mg/lb) of caffeine may be used as a safe alternative to anhydrous caffeine to improve endurance performance. PMID:26568580

  10. Modulatory effects of caffeine on oxidative stress and anxiety-like behavior in ovariectomized rats.

    PubMed

    Caravan, Ionut; Sevastre Berghian, Alexandra; Moldovan, Remus; Decea, Nicoleta; Orasan, Remus; Filip, Gabriela Adriana

    2016-09-01

    Menopause is accompanied by enhanced oxidative stress and behavioral changes, effects attenuated by antioxidants. The aim of this study was to evaluate the effects of caffeine on behavior and oxidative stress in an experimental model of menopause. Female rats were divided into the following groups: sham-operated (CON), sham-operated and caffeine-treated (CAF), ovariectomized (OVX), ovariectomized and caffeine-treated (OVX+CAF). Caffeine (6 mg/kg) and vehicle were administered for 21 days (subchronic) and 42 days (chronic), using 2 experimental subsets. Behavioral tests and oxidative stress parameters in the blood, whole brain, and hippocampus were assessed. The subchronic administration of caffeine decreased the lipid peroxidation and improved the antioxidant defense in the blood and brain. The GSH/GGSG ratio in the brain was improved by chronic administration, with reduced activities of antioxidant enzymes and enhanced nitric oxide and malondialdehyde levels. In particular, the lipid peroxidation in the hippocampus decreased in both experiments. The rats became hyperactive after 21 days of treatment, but no effect was observed after chronic administration. In both experimental subsets, caffeine had anxiolytic effects as tested in elevated plus maze. The administration of low doses of caffeine, for a short period of time, may be a new therapeutic approach to modulating the oxidative stress and anxiety in menopause. PMID:27333093

  11. Caffeine therapy in preterm infants

    PubMed Central

    Abdel-Hady, Hesham; Nasef, Nehad; Shabaan, Abd Elazeez; Nour, Islam

    2015-01-01

    Caffeine is the most commonly used medication for treatment of apnea of prematurity. Its effect has been well established in reducing the frequency of apnea, intermittent hypoxemia, and extubation failure in mechanically ventilated preterm infants. Evidence for additional short-term benefits on reducing the incidence of bronchopulmonary dysplasia and patent ductus arteriosus has also been suggested. Controversies exist among various neonatal intensive care units in terms of drug efficacy compared to other methylxanthines, dosage regimen, time of initiation, duration of therapy, drug safety and value of therapeutic drug monitoring. In the current review, we will summarize the available evidence for the best practice in using caffeine therapy in preterm infants. PMID:26566480

  12. Caffeine therapy in preterm infants.

    PubMed

    Abdel-Hady, Hesham; Nasef, Nehad; Shabaan, Abd Elazeez; Nour, Islam

    2015-11-01

    Caffeine is the most commonly used medication for treatment of apnea of prematurity. Its effect has been well established in reducing the frequency of apnea, intermittent hypoxemia, and extubation failure in mechanically ventilated preterm infants. Evidence for additional short-term benefits on reducing the incidence of bronchopulmonary dysplasia and patent ductus arteriosus has also been suggested. Controversies exist among various neonatal intensive care units in terms of drug efficacy compared to other methylxanthines, dosage regimen, time of initiation, duration of therapy, drug safety and value of therapeutic drug monitoring. In the current review, we will summarize the available evidence for the best practice in using caffeine therapy in preterm infants. PMID:26566480

  13. An enhanced treatment program with markedly reduced mortality after a transtibial or higher non-traumatic lower extremity amputation.

    PubMed

    Kristensen, Morten T; Holm, Gitte; Krasheninnikoff, Michael; Jensen, Pia S; Gebuhr, Peter

    2016-06-01

    Background and purpose - Historically, high 30-day and 1-year mortality post-amputation rates (> 30% and 50%, respectively) have been reported in patients with a transtibial or higher non-traumatic lower extremity amputation (LEA). We evaluated whether allocating experienced staff and implementing an enhanced, multidisciplinary recovery program would reduce the mortality rates. We also determined factors that influenced mortality rates. Patients and methods - 129 patients with a LEA were consecutively included over a 2-year period, and followed after admission to an acute orthopedic ward. Mortality was compared with historical and concurrent national controls in Denmark. Results - The 30-day and 1-year mortality rates were 16% and 37%, respectively, in the intervention group, as compared to 35% and 59% in the historical control group treated in the same orthopedic ward. Cox proportional harzards models adjusted for age, sex, residential and health status, the disease that caused the amputation, and the index amputation level showed that 30-day and 1-year mortality risk was reduced by 52% (HR =0.48, 95% CI: 0.25-0.91) and by 46% (HR =0.54, 95% CI: 0.35-0.86), respectively, in the intervention group. The risk of death was increased for patients living in a nursing home, for patients with a bilateral LEA, and for patients with low health status. Interpretation - With similarly frail patient groups and instituting an enhanced program for patients after LEA, the risks of death by 30 days and by 1 year after LEA were markedly reduced after allocating staff with expertise. PMID:27088484

  14. An enhanced treatment program with markedly reduced mortality after a transtibial or higher non-traumatic lower extremity amputation

    PubMed Central

    Kristensen, Morten T; Holm, Gitte; Krasheninnikoff, Michael; Jensen, Pia S; Gebuhr, Peter

    2016-01-01

    Background and purpose Historically, high 30-day and 1-year mortality post-amputation rates (> 30% and 50%, respectively) have been reported in patients with a transtibial or higher non-traumatic lower extremity amputation (LEA). We evaluated whether allocating experienced staff and implementing an enhanced, multidisciplinary recovery program would reduce the mortality rates. We also determined factors that influenced mortality rates. Patients and methods 129 patients with a LEA were consecutively included over a 2-year period, and followed after admission to an acute orthopedic ward. Mortality was compared with historical and concurrent national controls in Denmark. Results The 30-day and 1-year mortality rates were 16% and 37%, respectively, in the intervention group, as compared to 35% and 59% in the historical control group treated in the same orthopedic ward. Cox proportional harzards models adjusted for age, sex, residential and health status, the disease that caused the amputation, and the index amputation level showed that 30-day and 1-year mortality risk was reduced by 52% (HR =0.48, 95% CI: 0.25–0.91) and by 46% (HR =0.54, 95% CI: 0.35–0.86), respectively, in the intervention group. The risk of death was increased for patients living in a nursing home, for patients with a bilateral LEA, and for patients with low health status. Interpretation With similarly frail patient groups and instituting an enhanced program for patients after LEA, the risks of death by 30 days and by 1 year after LEA were markedly reduced after allocating staff with expertise. PMID:27088484

  15. Antibody-enhanced dengue disease generates a marked CNS inflammatory response in the black-tufted marmoset Callithrix penicillata.

    PubMed

    Vasconcelos, Barbara Cristina Baldez; Vieira, Juliana Almeida; Silva, Geane Oliveira; Fernandes, Taiany Nogueira; Rocha, Luciano Chaves; Viana, André Pereira; Serique, Cássio Diego Sá; Filho, Carlos Santos; Bringel, Raissa Aires Ribeiro; Teixeira, Francisco Fernando Dacier Lobato; Ferreira, Milene Silveira; Casseb, Samir Mansour Moraes; Carvalho, Valéria Lima; de Melo, Karla Fabiane Lopes; de Castro, Paulo Henrique Gomes; Araújo, Sanderson Corrêa; Diniz, José Antonio Picanço; Demachki, Samia; Anaissi, Ana Karyssa Mendes; Sosthenes, Marcia Consentino Kronka; Vasconcelos, Pedro Fernando da Costa; Anthony, Daniel Clive; Diniz, Cristovam Wanderley Picanço; Diniz, Daniel Guerreiro

    2016-02-01

    Severe dengue disease is often associated with long-term neurological impairments, but it is unclear what mechanisms are associated with neurological sequelae. Previously, we demonstrated antibody-enhanced dengue disease (ADE) dengue in an immunocompetent mouse model with a dengue virus 2 (DENV2) antibody injection followed by DENV3 virus infection. Here we migrated this ADE model to Callithrix penicillata. To mimic human multiple infections of endemic zones where abundant vectors and multiple serotypes co-exist, three animals received weekly subcutaneous injections of DENV3 (genotype III)-infected supernatant of C6/36 cell cultures, followed 24 h later by anti-DENV2 antibody for 12 weeks. There were six control animals, two of which received weekly anti-DENV2 antibodies, and four further animals received no injections. After multiple infections, brain, liver, and spleen samples were collected and tissue was immunolabeled for DENV3 antigens, ionized calcium binding adapter molecule 1, Ki-67, TNFα. There were marked morphological changes in the microglial population of ADE monkeys characterized by more highly ramified microglial processes, higher numbers of trees and larger surface areas. These changes were associated with intense TNFα-positive immunolabeling. It is unclear why ADE should generate such microglial activation given that IgG does not cross the blood-brain barrier, but this study reveals that in ADE dengue therapy targeting the CNS host response is likely to be important. PMID:26303046

  16. Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain

    SciTech Connect

    Volkow, N. D.; Wang, G. -J.; Logan, J.; Alexoff, D.; Fowler, J. S.; Thanos, P. K.; Wong, C.; Casado, V.; Ferre, S.; Tomasi, D.

    2015-04-14

    Caffeine, the most widely consumed psychoactive substance in the world, is used to promote wakefulness and enhance alertness. Like other wake-promoting drugs (stimulants and modafinil), caffeine enhances dopamine (DA) signaling in the brain, which it does predominantly by antagonizing adenosine A2A receptors (A2AR). However, it is unclear if caffeine, at the doses consumed by humans, increases DA release or whether it modulates the functions of postsynaptic DA receptors through its interaction with adenosine receptors, which modulate them. We used positron emission tomography and [11C]raclopride (DA D2/D3 receptor radioligand sensitive to endogenous DA) to assess if caffeine increased DA release in striatum in 20 healthy controls. Caffeine (300mg p.o.) significantly increased the availability of D2/D3 receptors in putamen and ventral striatum, but not in caudate, when compared with placebo. In addition, caffeine-induced increases in D2/D3 receptor availability in the ventral striatum were associated with caffeine-induced increases in alertness. Our findings indicate that in the human brain, caffeine, at doses typically consumed, increases the availability of DA D2/D3 receptors, which indicates that caffeine does not increase DA in the striatum for this would have decreased D2/D3 receptor availability. Instead, we interpret our findings to reflect an increase in D2/D3 receptor levels in striatum with caffeine (or changes in affinity). Furthermore, the association between increases in D2/D3 receptor availability in ventral striatum and alertness suggests that caffeine might enhance arousal, in part, by upregulating D2/D3 receptors.

  17. [Mechanisms of caffeine-induced diuresis].

    PubMed

    Marx, Barbara; Scuvée, Éléonore; Scuvée-Moreau, Jacqueline; Seutin, Vincent; Jouret, François

    2016-05-01

    Caffeine is an alkaloid which belongs to the family of methylxanthines and is present in beverages, food and drugs. Caffeine competitively antagonizes the adenosine receptors (AR), which are G protein-coupled receptors largely distributed throughout the body, including brain, heart, vessels and kidneys. Caffeine consumption has a well-known diuretic effect. The homeostasis of salt and water involves different segments of the nephron, in which adenosine plays complex roles depending on the differential expression of AR. Hence, caffeine increases glomerular filtration rate by opposing the vasoconstriction of renal afferent arteriole mediated by adenosine via type 1 AR during the tubuloglomerular feedback. Caffeine also inhibits Na(+) reabsorption at the level of renal proximal tubules. In addition, caffeine perturbs the hepatorenal reflex via sensory nerves in Mall's intrahepatic spaces. Here, we review the physiology of caffeine-induced natriuresis and diuresis, as well as the putative pathological implications. PMID:27225921

  18. Prenatal caffeine ingestion induces transgenerational neuroendocrine metabolic programming alteration in second generation rats

    SciTech Connect

    Luo, Hanwen; Deng, Zixin; Liu, Lian; Shen, Lang; Kou, Hao; He, Zheng; Ping, Jie; Xu, Dan; Ma, Lu; Chen, Liaobin; Wang, Hui

    2014-02-01

    Our previous studies have demonstrated that prenatal caffeine ingestion induces an increased susceptibility to metabolic syndrome with alterations of glucose and lipid metabolic phenotypes in adult first generation (F1) of intrauterine growth retardation (IUGR) rats, and the underlying mechanism is originated from a hypothalamic–pituitary–adrenal (HPA) axis-associated neuroendocrine metabolic programming alteration in utero. This study aims to investigate the transgenerational effects of this programming alteration in adult second generation (F2). Pregnant Wistar rats were administered with caffeine (120 mg/kg·d) from gestational day 11 until delivery. Four groups in F2 were set according to the cross-mating between control and caffeine-induced IUGR rats. F2 were subjected to a fortnight ice water swimming stimulus on postnatal month 4, and blood samples were collected before and after stress. Results showed that the majority of the activities of HPA axis and phenotypes of glucose and lipid metabolism were altered in F2. Particularly, comparing with the control group, caffeine groups had an enhanced corticosterone levels after chronic stress. Compared with before stress, the serum glucose levels were increased in some groups whereas the triglyceride levels were decreased. Furthermore, total cholesterol gain rates were enhanced but the high-density lipoprotein-cholesterol gain rates were decreased in most caffeine groups after stress. These transgenerational effects were characterized partially with gender and parental differences. Taken together, these results indicate that the reproductive and developmental toxicities and the neuroendocrine metabolic programming mechanism by prenatal caffeine ingestion have transgenerational effects in rats, which may help to explain the susceptibility to metabolic syndrome and associated diseases in F2. - Highlights: • Caffeine-induced neuroendocrine metabolic programming of HPA has hereditary effect. • Caffeine

  19. Induction of sister chromatid exchange in preimplantation mouse embryos in vitro by /sup 3/H-thymidine or ultraviolet light in combination with caffeine

    SciTech Connect

    Mueller, W.U.S.; Spindle, A.

    1986-01-01

    Preimplantation mouse embryos were exposed in vitro to /sup 3/H-thymidine (25, 100, or 250 Bq/ml) or ultraviolet (UV) light (1.35 or 4.05 J/m2), either alone or in combination with caffeine (1 mM with /sup 3/H-thymidine and 0.5 mM with UV light). Exposure to /sup 3/H-thymidine lasted for 2 days, from the two-cell stage to the late morula/early blastocyst stage, and UV radiation was applied acutely at the late morula/early blastocyst stage. The effects were quantified by the sister chromatid exchange (SCE) assay. All three agents induced SCEs when used singly. /sup 3/H-thymidine was effective in inducing SCEs only at 250 Bq/ml, whereas UV light was effective at both fluences. Although caffeine did not induce SCEs when it was added before exposure to bromodeoxyuridine (BrdUrd), which is used to visualize SCEs, it did induce SCEs when present during the entire culture period (/sup 3/H-thymidine experiments) or during incubation in BrdUrd (UV experiments). Caffeine markedly enhanced the SCE-inducing effect of UV light but did not influence the effect of /sup 3/H-thymidine.

  20. Caffeine and the common cold.

    PubMed

    Smith, A; Thomas, M; Perry, K; Whitney, H

    1997-01-01

    An experiment was carried out to determine whether caffeinated and decaffeinated coffee removed the malaise (reduced alertness, slower psychomotor performance) associated with having a common cold. One hundred volunteers were tested when healthy and 46 returned to the laboratory when they developed colds. Those subjects who remained healthy were then recalled as a control group. On the second visit subjects carried out two sessions, one pre-drink and another an hour after the drink. Subjects were randomly assigned to one of the following three conditions, caffeinated coffee (1.5 mg/kg caffeine/body weight), decaffeinated coffee or fruit juice. Subjects with colds reported decreased alertness and were slower at performing psychomotor tasks. Caffeine increased the alertness and performance of the colds subjects to the same level as the healthy group and decaffeinated coffee also led to an improvement. These results suggest that drugs which increase alertness can remove the malaise associated with the common cold, and that increased stimulation of the sensory afferent nerves may also be beneficial. PMID:9443519

  1. Caffeine Use Affects Pregnancy Outcome

    ERIC Educational Resources Information Center

    Diego, Miguel; Field, Tiffany; Hernandez-Reif, Maria; Vera, Yanexy; Gil, Karla; Gonzalez-Garcia, Adolfo

    2008-01-01

    A sample of 750 women were interviewed during pregnancy on their depression and anxiety symptoms, substance use and demographic variables. A subsample was seen again at the neonatal stage (n = 152), and their infants were observed for sleep-wake behavior. Symptoms of depression and anxiety were related to caffeine use. Mothers who consumed more…

  2. Caffeine Modulates Attention Network Function

    ERIC Educational Resources Information Center

    Brunye, Tad T.; Mahoney, Caroline R.; Lieberman, Harris R.; Taylor, Holly A.

    2010-01-01

    The present work investigated the effects of caffeine (0 mg, 100 mg, 200 mg, 400 mg) on a flanker task designed to test Posner's three visual attention network functions: alerting, orienting, and executive control [Posner, M. I. (2004). "Cognitive neuroscience of attention". New York, NY: Guilford Press]. In a placebo-controlled, double-blind…

  3. What can isolated skeletal muscle experiments tell us about the effects of caffeine on exercise performance?

    PubMed Central

    Tallis, Jason; Duncan, Michael J; James, Rob S

    2015-01-01

    Caffeine is an increasingly popular nutritional supplement due to the legal, significant improvements in sporting performance that it has been documented to elicit, with minimal side effects. Therefore, the effects of caffeine on human performance continue to be a popular area of research as we strive to improve our understanding of this drug and make more precise recommendations for its use in sport. Although variations in exercise intensity seems to affect its ergogenic benefits, it is largely thought that caffeine can induce significant improvements in endurance, power and strength-based activities. There are a number of limitations to testing caffeine-induced effects on human performance that can be better controlled when investigating its effects on isolated muscles under in vitro conditions. The hydrophobic nature of caffeine results in a post-digestion distribution to all tissues of the body making it difficult to accurately quantify its key mechanism of action. This review considers the contribution of evidence from isolated muscle studies to our understating of the direct effects of caffeine on muscle during human performance. The body of in vitro evidence presented suggests that caffeine can directly potentiate skeletal muscle force, work and power, which may be important contributors to the performance-enhancing effects seen in humans. PMID:25988508

  4. What can isolated skeletal muscle experiments tell us about the effects of caffeine on exercise performance?

    PubMed

    Tallis, Jason; Duncan, Michael J; James, Rob S

    2015-08-01

    Caffeine is an increasingly popular nutritional supplement due to the legal, significant improvements in sporting performance that it has been documented to elicit, with minimal side effects. Therefore, the effects of caffeine on human performance continue to be a popular area of research as we strive to improve our understanding of this drug and make more precise recommendations for its use in sport. Although variations in exercise intensity seems to affect its ergogenic benefits, it is largely thought that caffeine can induce significant improvements in endurance, power and strength-based activities. There are a number of limitations to testing caffeine-induced effects on human performance that can be better controlled when investigating its effects on isolated muscles under in vitro conditions. The hydrophobic nature of caffeine results in a post-digestion distribution to all tissues of the body making it difficult to accurately quantify its key mechanism of action. This review considers the contribution of evidence from isolated muscle studies to our understating of the direct effects of caffeine on muscle during human performance. The body of in vitro evidence presented suggests that caffeine can directly potentiate skeletal muscle force, work and power, which may be important contributors to the performance-enhancing effects seen in humans. PMID:25988508

  5. Consumption of caffeinated beverages and the awareness of their caffeine content among Dutch students.

    PubMed

    Mackus, Marlou; van de Loo, Aurora J A E; Benson, Sarah; Scholey, Andrew; Verster, Joris C

    2016-08-01

    The purpose of the current study was to examine the knowledge of caffeine content of a variety of caffeinated beverages among Dutch university students. A pencil-and-paper survey was conducted among N = 800 Dutch students. Most participants (87.8%) reported consuming caffeinated beverages during the past 24 h. Their mean ± SD past 24-h caffeine intake from beverages was 144.2 ± 169.5 mg (2.2 ± 3.0 mg/kg bw). Most prevalent sources of caffeine were coffee beverages (50.8%) and tea (34.8%), followed by energy drink (9.2%), cola (4.7%), and chocolate milk (0.5%). Participants had poor knowledge on the relative caffeine content of caffeinated beverages. That is, they overestimated the caffeine content of energy drinks and cola, and underestimated the caffeine content of coffee beverages. If caffeine consumption is a concern, it is important to inform consumers about the caffeine content of all caffeine containing beverages, including coffee and tea. The current findings support previous research that the most effective way to reduce caffeine intake is to limit the consumption of coffee beverages and tea. PMID:27142708

  6. Effect of energy drink and caffeinated beverage consumption on sleep, mood, and performance in children and adolescents.

    PubMed

    Owens, Judith A; Mindell, Jodi; Baylor, Allison

    2014-10-01

    The increasing availability of highly caffeinated beverages, including energy drinks, in the United States has resulted in a rise in consumption by children and adolescents. In addition, there is mounting evidence that these products are often consumed by youth for their perceived fatigue-mitigating and mood- or performance-enhancing effects. Although such perceptions by children and adolescents about the potential consequences of caffeine consumption are highly likely to influence decision making regarding the use of such products, there is still a relative paucity of studies that focus on the effect of caffeinated beverages on sleep, mood, and performance in the pediatric population. This review summarizes the following aspects of this topic, as derived from the information currently available: 1) the perception, among youth, of caffeine's risks and benefits and the sources of information about caffeine, particularly with regard to sleep, mood, and performance; 2) the bidirectional effect of caffeine on sleep in children and adolescents and the association of caffeine with other sleep-related practices, and 3) the evidence that supports caffeine as a performance and mood enhancer as well as a countermeasure to sleepiness in the pediatric population. Finally, gaps in knowledge are identified, and a direction for future research is outlined. PMID:25293545

  7. The effect of caffeine on renal epithelial cells from patients with autosomal dominant polycystic kidney disease.

    PubMed

    Belibi, Franck A; Wallace, Darren P; Yamaguchi, Tamio; Christensen, Marcy; Reif, Gail; Grantham, Jared J

    2002-11-01

    Autosomal dominant polycystic kidney disease (ADPKD) is a hereditary disorder characterized by the progressive enlargement of cysts derived from tubules. Tubule cell proliferation and chloride-dependent fluid accumulation, mechanisms underlying cyst expansion, are accelerated by adenosine 3':5'-cyclic monophosphate (cAMP). This study examined the extent to which caffeine may stimulate the production of cAMP by cyst epithelial cells, thereby adversely increasing proliferation and fluid secretion. Mural epithelial cells from ADPKD cysts and normal human kidney cortex cells (HKC) were cultured, and cAMP levels were determined in response to caffeine and receptor-mediated agonists linked to adenylyl cyclase. Caffeine, a methylxanthine, slightly increased basal levels of cAMP, as did other nonselective phosphodiesterase (PDE) inhibitors, 1-methyl-3- isobutyl xanthine and theophylline and rolipram, a specific PDE IV inhibitor. More importantly, clinically relevant concentrations of caffeine (10 to 50 micro M) potentiated the effects of desmopressin (DDAVP), prostaglandin E(2) (PGE(2)), and isoproterenol to increase cAMP levels in both ADPKD and HKC cells. By contrast, at concentrations that augmented the DDAVP response, caffeine attenuated cAMP accumulation by adenosine, implicating an action apart from the inhibition of PDE. Caffeine enhanced the effect of DDAVP to stimulate transepithelial short-circuit current of polarized ADPKD monolayers, reflecting an increase in chloride secretion. Caffeine potentiated the effect of DDAVP and PGE(2) to increase the levels of phosphorylated extracellular signal-regulated kinase (P-ERK). By contrast, P-ERK levels in HKC cells were not raised by increased intracellular concentrations of cAMP. It is concluded that PDE inhibition by caffeine increases the accumulation of cAMP, and through this mechanism activates the ERK pathway to cellular proliferation and increases transepithelial fluid secretion in ADPKD cystic epithelium. Caffeine

  8. Caffeine, maximal power output and fatigue.

    PubMed Central

    Williams, J H; Signorile, J F; Barnes, W S; Henrich, T W

    1988-01-01

    The purpose of this investigation was to determine the effects of caffeine ingestion on maximal power output and fatigue during short term, high intensity exercise. Nine adult males performed 15 s maximal exercise bouts 60 min after ingestion of caffeine (7 mg.kg-1) or placebo. Exercise bouts were carried out on a modified cycle ergometer which allowed power output to be computed for each one-half pedal stroke via microcomputer. Peak power output under caffeine conditions was not significantly different from that obtained following placebo ingestion. Similarly, time to peak power, total work, power fatigue index and power fatigue rate did not differ significantly between caffeine and placebo conditions. These results suggest that caffeine ingestion does not increase one's maximal ability to generate power. Further, caffeine does not alter the rate or magnitude of fatigue during high intensity, dynamic exercise. PMID:3228680

  9. Effects of caffeine ingestion on metabolism and exercise performance.

    PubMed

    Costill, D L; Dalsky, G P; Fink, W J

    1978-01-01

    In an effort to assess the effects of caffeine ingestion on metabolism and performance during prolonged exercise, nine competitive cyclists (two females and seven males) exercised until exhaustion on a bicycle ergometer at 80% of Vo2 max. One trial was performed an hour after ingesting decaffeinated coffee (Trial D), while a second trial (C) required that each subject consume coffee containing 330 mg of caffeine 60 min before the exercise. Following the ingestion of caffeine (Trial C), the subjects were able to perform an average of 90.2 (SE +/- 7.2) min of cycling as compared to an average of 75.5 (SE +/- 5.1) min in the D Trial. Measurements of plasma free fatty acids, glycerol and respiratory exchange ratios evidenced a greater rate of lipid metabolism during the caffeine trial as compared to the decaffeinated exercise treatment. Calculations of carbohydrate (CHO) metabolism from respiratory exchange data revealed that the subjects oxidized roughly 240 g of CHO in both trials. Fat oxidation, however, was significantly higher (P less than 0.05) during the C Trial (118 g or 1.31 g/min) than in the D Trial (57 g or 0.75 g/min). On the average the participants rated (Perceived Exertion Scale) their effort during the C Trial to be significantly (P less than 0.05) easier than the demands of the D treatment. Thus, the enhanced endurance performance observed in the C Trial was likely the combined effects of caffeine on lipolysis and its positive influence on nerve impulse transmission. PMID:723503

  10. Simple electrochemical sensor for caffeine based on carbon and Nafion-modified carbon electrodes.

    PubMed

    Torres, A Carolina; Barsan, Madalina M; Brett, Christopher M A

    2014-04-15

    A simple, economic, highly sensitive and highly selective method for the detection of caffeine has been developed at bare and Nafion-modified glassy carbon electrodes (GCE). The electrochemical behaviour of caffeine was examined in electrolyte solutions of phosphate buffer saline, sodium perchlorate, and in choline chloride plus oxalic acid, using analytical determinations by fixed potential amperometry, phosphate buffer saline being the best. Modifications of the GCE surface with poly(3,4-ethylenedioxythiophene) (PEDOT), Nafion, and multi-walled carbon nanotubes were tested in order to evaluate possible sensor performance enhancements, Nafion giving the most satisfactory results. The effect of interfering compounds usually found in samples containing caffeine was examined at GCE without and with Nafion coating, to exclude interferences, and the sensors were successfully applied to determine the caffeine content in commercial beverages and drugs. PMID:24295698

  11. Caffeine deprivation state modulates coffee consumption but not attentional bias for caffeine-related stimuli.

    PubMed

    Stafford, L D; Yeomans, M R

    2005-11-01

    Previous research has shown that caffeine deprivation state can exert a strong influence on the ability of caffeine to reinforce behaviour. Recent work has also found evidence for an attentional bias in habitual caffeine users. It remains unclear whether deprivation state can influence attentional bias. Here we explored the relationship between caffeine deprivation, attentional bias to caffeine-related stimuli and subsequent caffeine reinforcement measured by consumption of coffee. In three experiments, participants (between-subjects: n=28; within-subjects: n=20, within-subjects: n=20) were preloaded with either caffeine (experiments 1 and 3 : 100 mg; experiment 2 : 150 mg) or placebo, and in experiments 1 and 2 they completed a novel attentional bias task involving pre-attentive word recognition, and in experiment 3 a dot-probe task. In experiments 2 and 3, this was followed by a test of coffee consumption. Greater recognition for caffeine-related words (experiments 1 and 2) and faster reaction times to probes replacing caffeine-related rather than control stimuli (experiment 3) confirmed caffeine-related attentional biases, but in no case was this affected by manipulation of caffeine-deprivation state. Participants in a deprived versus nondeprived state, however, experienced increases in drowsiness and headaches (experiment 2) and reduced alertness (experiment 3). Further, coffee consumption was greatest when participants were caffeine-deprived than when they were nondeprived. Findings are discussed in relation to prevailing theories of drug addiction. PMID:16170233

  12. Role of adenosine receptors in caffeine tolerance

    SciTech Connect

    Holtzman, S.G.; Mante, S.; Minneman, K.P. )

    1991-01-01

    Caffeine is a competitive antagonist at adenosine receptors. Receptor up-regulation during chronic drug treatment has been proposed to be the mechanism of tolerance to the behavioral stimulant effects of caffeine. This study reassessed the role of adenosine receptors in caffeine tolerance. Separate groups of rats were given scheduled access to drinking bottles containing plain tap water or a 0.1% solution of caffeine. Daily drug intake averaged 60-75 mg/kg and resulted in complete tolerance to caffeine-induced stimulation of locomotor activity, which could not be surmounted by increasing the dose of caffeine. 5'-N-ethylcarboxamidoadenosine (0.001-1.0 mg/kg) dose dependently decreased the locomotor activity of caffeine-tolerant rats and their water-treated controls but was 8-fold more potent in the latter group. Caffeine (1.0-10 mg/kg) injected concurrently with 5-N-ethylcarboxamidoadenosine antagonized the decreases in locomotor activity comparably in both groups. Apparent pA2 values for tolerant and control rats also were comparable: 5.05 and 5.11. Thus, the adenosine-antagonist activity of caffeine was undiminished in tolerant rats. The effects of chronic caffeine administration on parameters of adenosine receptor binding and function were measured in cerebral cortex. There were no differences between brain tissue from control and caffeine-treated rats in number and affinity of adenosine binding sites or in receptor-mediated increases (A2 adenosine receptor) and decreases (A1 adenosine receptor) in cAMP accumulation. These results are consistent with theoretical arguments that changes in receptor density should not affect the potency of a competitive antagonist. Experimental evidence and theoretical considerations indicate that up-regulation of adenosine receptors is not the mechanism of tolerance to caffeine-induced stimulation of locomotor activity.

  13. The effect of ephedra and caffeine on maximal strength and power in resistance-trained athletes.

    PubMed

    Williams, Andrew D; Cribb, Paul J; Cooke, Matthew B; Hayes, Alan

    2008-03-01

    Caffeine and ephedrine-related alkaloids recently have been removed from International Olympic Committee banned substances lists, whereas ephedrine itself is now permissible at urinary concentrations less than 10 mug.mL. The changes to the list may contribute to an increased use of caffeine and ephedra as ergogenic aids by athletes. Consequently, we sought to investigate the effects of ingesting caffeine (C) or a combination of ephedra and caffeine (C + E) on muscular strength and anaerobic power using a double-blind, crossover design. Forty-five minutes after ingesting a glucose placebo (P: 300 mg), C (300 mg) or C + E (300 mg + 60 mg), 9 resistance-trained male participants were tested for maximal strength by bench press [BP; 1 repetition maximum (1RM)] and latissimus dorsi pull down (LP; 1RM). Subjects also performed repeated repetitions at 80% of 1RM on both BP and LP until exhaustion. After this test, subjects underwent a 30-second Wingate test to determine peak anaerobic cycling power, mean power, and fatigue index. Although subjects reported increased alertness and enhanced mood after supplementation with caffeine and ephedra, there were no significant differences between any of the treatments in muscle strength, muscle endurance, or peak anaerobic power. Our results do not support the contention that supplementation with ephedra or caffeine will enhance either muscle strength or anaerobic exercise performance. PMID:18550961

  14. Effect of caffeine contained in a cup of coffee on microvascular function in healthy subjects.

    PubMed

    Noguchi, Katsuhiko; Matsuzaki, Toshihiro; Sakanashi, Mayuko; Hamadate, Naobumi; Uchida, Taro; Kina-Tanada, Mika; Kubota, Haruaki; Nakasone, Junko; Sakanashi, Matao; Ueda, Shinichiro; Masuzaki, Hiroaki; Ishiuchi, Shogo; Ohya, Yusuke; Tsutsui, Masato

    2015-02-01

    Recent epidemiological studies have demonstrated that coffee drinking is associated with reduced mortality of cardiovascular disease. However, its precise mechanisms remain to be clarified. In this study, we examined whether single ingestion of caffeine contained in a cup of coffee improves microvascular function in healthy subjects. A double-blind, placebo-controlled, crossover study was performed in 27 healthy volunteers. A cup of either caffeinated or decaffeinated coffee was drunk by the subjects, and reactive hyperemia of finger blood flow was assessed by laser Doppler flowmetry. In an interval of more than 2 days, the same experimental protocol was repeated with another coffee in a crossover manner. Caffeinated coffee intake slightly but significantly elevated blood pressure and decreased finger blood flow as compared with decaffeinated coffee intake. There was no significant difference in heart rate between caffeinated and decaffeinated coffee intake. Importantly, caffeinated coffee intake significantly enhanced post-occlusive reactive hyperemia of finger blood flow, an index of microvascular endothelial function, compared with decaffeinated coffee intake. These results provide the first evidence that caffeine contained in a cup of coffee enhances microvascular function in healthy individuals. PMID:25727960

  15. Caffeine induces cardiomyocyte hypertrophy via p300 and CaMKII pathways.

    PubMed

    Shi, Liang; Xu, Hao; Wei, Jinhong; Ma, Xingfeng; Zhang, Jianbao

    2014-09-25

    Caffeine is commonly utilized to trigger intracellular calcium in cardiomyocyte. It is well accepted that caffeine could induce cardiac arrhythmia, but it is not clear with regard of its impacts on the cardiac function. This article presents a recent study concerning the effects of caffeine on the cardiomyocyte hypertrophy and the associated signal pathway. The experimental results showed that the total protein contents, the surface area of cardiomyocyte and β-myosin heavy chain (β-MHC) expression increased in ventricular myocytes of neonatal Sprague-Dawley (SD) rats after 24h caffeine incubation. It is also observed that the basal intracellular calcium (Ca(2+)) level has increased, while the amplitude of Ca(2+) oscillation and Ca(2+) content have decreased in sarcoplasmic reticulum (SR). The caffeine-induced myocyte enhancer factor-2 (MEF2) expression and hypertrophy can be completely abolished by the inhibition of cardiac ryanodine receptor (RyR2), as well as KN93 and curcumin treatments. Meanwhile, the amplitude of Ca(2+) oscillation and the Ca(2+) content of SR in the completely-inhibited group have reached the physiological level. These results suggest that the caffeine-induced cardiomyocyte hypertrophy established the connection between Ca(2+) release from SR and cytosol that activates CaMKII and p300, which in turn enhances the expression of MEF2 that promotes cardiomyocyte hypertrophy. PMID:25093688

  16. Caffeine consumption amongst British athletes following changes to the 2004 WADA prohibited list.

    PubMed

    Chester, N; Wojek, N

    2008-06-01

    This study was undertaken to examine self-reported caffeine consumption and reasons for its use, amongst UK athletes, following its removal from the 2004 World Anti-Doping Agency (WADA) Prohibited List. A convenience sample of track and field athletes (n = 193) and cyclists (n = 287) completed a postal or Web-based questionnaire. Messages were posted on athletics and cycling club Web sites and mailing lists to direct athletes to the Web-based questionnaire. Postal questionnaires were distributed at domestic sporting events. A higher proportion of cyclists (59.9 %) compared with track and field athletes (32.6 %) consumed caffeine to enhance performance (p < 0.001). A higher proportion of elite as opposed to sub-elite athletes representing cycling (p = 0.031) and athletics (p = 0.010) used caffeine to enhance performance. Of all caffeine containing products used, coffee, energy drinks, pharmaceutical preparations and caffeinated sports supplements were most prevalent. Results revealed that amongst UK athletes, the intention to use caffeine as an ergogenic aid was high, and that use was more widespread and accepted in competitive sport, especially at elite level, when compared to recreational sport. PMID:18027309

  17. The effect of a caffeinated mouth-rinse on endurance cycling time-trial performance.

    PubMed

    Doering, Thomas M; Fell, James W; Leveritt, Michael D; Desbrow, Ben; Shing, Cecilia M

    2014-02-01

    The purpose of this study was to investigate if acute caffeine exposure via mouth-rinse improved endurance cycling time-trial performance in well-trained cyclists. It was hypothesized that caffeine exposure at the mouth would enhance endurance cycling time-trial performance. Ten well-trained male cyclists (mean ± SD: 32.9 ± 7.5 years, 74.7 ± 5.3 kg, 176.8 ± 5.1cm, VO₂peak = 59.8 ± 3.5 ml·kg⁻¹·min⁻¹) completed two experimental time-trials following 24 hr of dietary and exercise standardization. A randomized, double-blind, placebo-controlled, cross-over design was employed whereby cyclists completed a time-trial in the fastest time possible, which was equivalent work to cycling at 75% of peak aerobic power output for 60 min. Cyclists were administered 25 ml mouth-rinses for 10 s containing either placebo or 35 mg of anhydrous caffeine eight times throughout the time-trial. Perceptual and physiological variables were recorded throughout. No significant improvement in time-trial performance was observed with caffeine (3918 ± 243 s) compared with placebo mouth-rinse (3940 ± 227 s). No elevation in plasma caffeine was detected due to the mouth-rinse conditions. Caffeine mouth-rinse had no significant effect on rating of perceived exertion, heart rate, rate of oxygen consumption or blood lactate concentration. Eight exposures of a 35 mg dose of caffeine at the buccal cavity for 10s does not significantly enhance endurance cycling time-trial performance, nor does it elevate plasma caffeine concentration. PMID:23980239

  18. Caffeine (1, 3, 7-trimethylxanthine) in foods: a comprehensive review on consumption, functionality, safety, and regulatory matters.

    PubMed

    Heckman, Melanie A; Weil, Jorge; Gonzalez de Mejia, Elvira

    2010-04-01

    Caffeine ranks as one of the top most commonly consumed dietary ingredients throughout the world. It is naturally found in coffee beans, cacao beans, kola nuts, guarana berries, and tea leaves including yerba mate. The total daily intake, as well as the major source of caffeine varies globally; however, coffee and tea are the 2 most prominent sources. Soft drinks are also a common source of caffeine as well as energy drinks, a category of functional beverages. Moderate caffeine consumption is considered safe and its use as a food ingredient has been approved, within certain limits, by numerous regulatory agencies around the world. Performance benefits attributed to caffeine include physical endurance, reduction of fatigue, and enhancing mental alertness and concentration. Caffeine has also been recently linked to weight loss and consequent reduction of the overall risks for developing the metabolic syndrome. However, the caloric contribution of caffeine-sweetened beverages needs to be considered in the overall energy balance. Despite all these benefits the potential negative effects of excessive caffeine intake should also be considered, particularly in children and pregnant women. PMID:20492310

  19. Alcohol and Caffeine: The Perfect Storm

    PubMed Central

    O'Brien, Mary Claire

    2011-01-01

    Although it is widely believed that caffeine antagonizes the intoxicating effects of alcohol, the molecular mechanisms underlying their interaction are incompletely understood. It is known that both caffeine and alcohol alter adenosine neurotransmission, but the relationship is complex, and may be dose dependent. In this article, we review the available literature on combining caffeine and alcohol. Ethical constraints prohibit laboratory studies that would mimic the high levels of alcohol intoxication achieved by many young people in real-world settings, with or without the addition of caffeine. We propose a possible neurochemical mechanism for the increase in alcohol consumption and alcohol-related consequences that have been observed in persons who simultaneously consume caffeine. Caffeine is a nonselective adenosine receptor antagonist. During acute alcohol intake, caffeine antagonizes the “unwanted” effects of alcohol by blocking the adenosine A1 receptors that mediate alcohol's somnogenic and ataxic effects. The A1 receptor–mediated “unwanted” anxiogenic effects of caffeine may be ameliorated by alcohol-induced increase in the extracellular concentration of adenosine. Moreover, by means of interactions between adenosine A2A and dopamine D2 receptors, caffeine-mediated blockade of adenosine A2A receptors can potentiate the effects of alcohol-induced dopamine release. Chronic alcohol intake decreases adenosine tone. Caffeine may provide a “treatment” for the withdrawal effects of alcohol by blocking the effects of upregulated A1 receptors. Finally, blockade of A2A receptors by caffeine may contribute to the reinforcing effects of alcohol. PMID:24761263

  20. Caffeine and caffeinated beverage consumption and fecundability in a preconception cohort.

    PubMed

    Wesselink, Amelia K; Wise, Lauren A; Rothman, Kenneth J; Hahn, Kristen A; Mikkelsen, Ellen M; Mahalingaiah, Shruthi; Hatch, Elizabeth E

    2016-07-01

    Caffeine is an adenosine receptor antagonist that may influence fertility by affecting ovulation, menstrual characteristics, or sperm quality. We studied the association between female and male preconception caffeine intake and fecundability in a North American prospective cohort study of 2135 pregnancy planners. Frequency of caffeinated beverage intake was self-reported at baseline. Outcome data were updated every 8 weeks until reported pregnancy; censoring occurred at 12 months. Adjusted fecundability ratios (FR) and 95% confidence intervals (CI) were estimated using proportional probabilities regression. Total caffeine intake among males, but not females, was associated with fecundability (FR for ≥300 vs. <100mg/day caffeine among males=0.72, 95% CI=0.54-0.96), although the association was not monotonic. With respect to individual beverages, caffeinated tea intake was associated with slight reductions in fecundability among females, and caffeinated soda and energy drink intake were associated with reduced fecundability among males. PMID:27112524

  1. Stimulatory effect of oral administration of tea, coffee or caffeine on UVB-induced apoptosis in the epidermis of SKH-1 mice

    SciTech Connect

    Conney, Allan H. Zhou, Sherry; Lee Maojung; Xie Jianguo; Yang, Chung S.; Lou Yourong; Lu Yaoping

    2007-11-01

    Oral administration of green tea or a caffeine solution, but not decaffeinated green tea, inhibits UVB-induced complete carcinogenesis in SKH-1 mice. Oral administration of green tea, coffee or a caffeine solution for 2 weeks enhanced UVB-induced increases in apoptosis in the epidermis, but these treatments had no effect in non-UVB treated normal epidermis. Our results suggest that administration of green tea, coffee and caffeine may inhibit UVB-induced carcinogenesis - at least in part - by enhancing UVB-induced apoptosis. Plasma levels of caffeine observed after its oral administration at cancer-preventive dose levels were within the range observed in moderate coffee drinkers. Topical applications of caffeine to mice previously treated with UVB for 20 weeks (high risk mice without tumors) inhibited the formation of tumors and stimulated apoptosis in the tumors but not in areas of the epidermis away from tumors. The selective effects of caffeine administration to stimulate UVB-induced apoptosis or apoptosis in tumors but not in normal epidermis or in areas of the epidermis away from tumors is of considerable interest, but the reasons for the selective effects of caffeine on apoptosis in DNA damaged tissues are unknown. Further studies are needed to determine mechanisms of these effects of caffeine and to determine the effects of caffeine administration on sunlight-induced actinic keratoses and squamous cell carcinomas in humans.

  2. Caffeine withdrawal and high-intensity endurance cycling performance.

    PubMed

    Irwin, Christopher; Desbrow, Ben; Ellis, Aleisha; O'Keeffe, Brooke; Grant, Gary; Leveritt, Michael

    2011-03-01

    In this study, we investigated the impact of a controlled 4-day caffeine withdrawal period on the effect of an acute caffeine dose on endurance exercise performance. Twelve well-trained and familiarized male cyclists, who were caffeine consumers (from coffee and a range of other sources), were recruited for the study. A double-blind placebo-controlled cross-over design was employed, involving four experimental trials. Participants abstained from dietary caffeine sources for 4 days before the trials and ingested capsules (one in the morning and one in the afternoon) containing either placebo or caffeine (1.5 mg · kg(-1) body weight · day(-1)). On day 5, capsules containing placebo or caffeine (3 mg · kg(-1) body weight) were ingested 90 min before completing a time trial, equivalent to one hour of cycling at 75% peak sustainable power output. Hence the study was designed to incorporate placebo-placebo, placebo-caffeine, caffeine-placebo, and caffeine-caffeine conditions. Performance time was significantly improved after acute caffeine ingestion by 1:49 ± 1:41 min (3.0%, P = 0.021) following a withdrawal period (placebo-placebo vs. placebo-caffeine), and by 2:07 ± 1:28 min (3.6%, P = 0.002) following the non-withdrawal period (caffeine-placebo vs. caffeine-caffeine). No significant difference was detected between the two acute caffeine trials (placebo-caffeine vs. caffeine-caffeine). Average heart rate throughout exercise was significantly higher following acute caffeine administration compared with placebo. No differences were observed in ratings of perceived exertion between trials. A 3 mg · kg(-1) dose of caffeine significantly improves exercise performance irrespective of whether a 4-day withdrawal period is imposed on habitual caffeine users. PMID:21279864

  3. Guarana Provides Additional Stimulation over Caffeine Alone in the Planarian Model

    PubMed Central

    Moustakas, Dimitrios; Mezzio, Michael; Rodriguez, Branden R.; Constable, Mic Andre; Mulligan, Margaret E.; Voura, Evelyn B.

    2015-01-01

    The stimulant effect of energy drinks is primarily attributed to the caffeine they contain. Many energy drinks also contain other ingredients that might enhance the tonic effects of these caffeinated beverages. One of these additives is guarana. Guarana is a climbing plant native to the Amazon whose seeds contain approximately four times the amount of caffeine found in coffee beans. The mix of other natural chemicals contained in guarana seeds is thought to heighten the stimulant effects of guarana over caffeine alone. Yet, despite the growing use of guarana as an additive in energy drinks, and a burgeoning market for it as a nutritional supplement, the science examining guarana and how it affects other dietary ingredients is lacking. To appreciate the stimulant effects of guarana and other natural products, a straightforward model to investigate their physiological properties is needed. The planarian provides such a system. The locomotor activity and convulsive response of planarians with substance exposure has been shown to provide an excellent system to measure the effects of drug stimulation, addiction and withdrawal. To gauge the stimulant effects of guarana we studied how it altered the locomotor activity of the planarian species Dugesia tigrina. We report evidence that guarana seeds provide additional stimulation over caffeine alone, and document the changes to this stimulation in the context of both caffeine and glucose. PMID:25880065

  4. The effects of caffeine in women during aerobic-dance bench stepping.

    PubMed

    Ahrens, Jennifer N; Lloyd, Lisa K; Crixell, Sylvia H; Walker, John L

    2007-02-01

    People of all ages and fitness levels participate regularly in aerobic-dance bench stepping (ADBS) to increase fitness and control body weight. Any reasonable method for enhancing the experience or effectiveness of ADBS would be beneficial. This study examined the acute effects of a single dose of caffeine on physiological responses during ADBS in women. When compared with a placebo, neither a 3- nor a 6-mg/kg dose of caffeine altered physiological responses or rating of perceived exertion (RPE) in 20 women (age 19-28 y) of average fitness level, not habituated to caffeine, while they performed an ADBS routine. Since neither dose of caffeine had any effect on VO2, VCO2, minute ventilation, respiratory-exchange ratio, rate of energy expenditure, heart rate, or RPE during ADBS exercise, it would not be prudent for a group exercise leader to recommend caffeine to increase energy cost or decrease perception of effort in an ADBS session. Furthermore, caffeine ingestion should not interfere with monitoring intensity using heart rate or RPE during ADBS. PMID:17460331

  5. Guarana provides additional stimulation over caffeine alone in the planarian model.

    PubMed

    Moustakas, Dimitrios; Mezzio, Michael; Rodriguez, Branden R; Constable, Mic Andre; Mulligan, Margaret E; Voura, Evelyn B

    2015-01-01

    The stimulant effect of energy drinks is primarily attributed to the caffeine they contain. Many energy drinks also contain other ingredients that might enhance the tonic effects of these caffeinated beverages. One of these additives is guarana. Guarana is a climbing plant native to the Amazon whose seeds contain approximately four times the amount of caffeine found in coffee beans. The mix of other natural chemicals contained in guarana seeds is thought to heighten the stimulant effects of guarana over caffeine alone. Yet, despite the growing use of guarana as an additive in energy drinks, and a burgeoning market for it as a nutritional supplement, the science examining guarana and how it affects other dietary ingredients is lacking. To appreciate the stimulant effects of guarana and other natural products, a straightforward model to investigate their physiological properties is needed. The planarian provides such a system. The locomotor activity and convulsive response of planarians with substance exposure has been shown to provide an excellent system to measure the effects of drug stimulation, addiction and withdrawal. To gauge the stimulant effects of guarana we studied how it altered the locomotor activity of the planarian species Dugesia tigrina. We report evidence that guarana seeds provide additional stimulation over caffeine alone, and document the changes to this stimulation in the context of both caffeine and glucose. PMID:25880065

  6. Analgesic effect of caffeine and clomipramine: a possible interaction between adenosine and serotonin systems.

    PubMed

    Bach-Rojecky, Lidija

    2003-03-01

    The goals of this study were to determine whether the nonselective adenosine receptor antagonist caffeine exerts an analgesic effect and to investigate the time-dependent influence of the selective serotonin reuptake inhibitor clomipramine on the action of caffeine. Results suggest a possible interaction between serotonin and adenosine systems, which may contribute to the analgesic action of drugs. Therefore, the hot-plate and formalin tests were employed in order to measure the response to painful thermic and chemical stimuli. Results have shown that caffeine (1.67, 16.7 and 67 mg kg(-1), i.p.) exerts a direct dose-dependent analgesic action. When caffeine (1.67 and 16.7 mg kg(-1)) was combined with clomipramine (3 mg kg(-1) i.p.), an enhanced analgesic effect was obtained. However, the same combinations were ineffective in a subacute model. In this model, clomipramine was administered for 14 days and the respective dose of caffeine was added on the last day. Therefore, it can be concluded that the serotonin system interacts with the analgesic action of caffeine and that a long-term use of clomipramine probably triggers subsensitivity of adenosine receptors. PMID:14769250

  7. Fatal caffeine overdose: two case reports.

    PubMed

    Kerrigan, Sarah; Lindsey, Tania

    2005-10-01

    Caffeine is a mild central nervous stimulant that occurs naturally in coffee beans, cocoa beans and tea leaves. In large doses, it can be profoundly toxic, resulting in arrhythmia, tachycardia, vomiting, convulsions, coma and death. The average cup of coffee or tea in the United States is reported to contain between 40 and 150 mg caffeine although specialty coffees may contain much higher doses. Over-the-counter supplements that are used to combat fatigue typically contain 100-200 mg caffeine per tablet and doses of 32-200mg are included in a variety of prescription drug mixtures. Fatal caffeine overdoses in adults are relatively rare and require the ingestion of a large quantity of the drug, typically in excess of 5 g. Over a period of approximately 12 months our office reported two cases of fatal caffeine intoxication. In the first case, the femoral blood of a 39-year-old female with a history of intravenous drug use contained 192 mg/L caffeine. In the second case, femoral blood from a 29-year-old male with a history of obesity and diabetes contained 567 mg/L caffeine. In both cases, the cause of death was ruled as caffeine intoxication and the manner of death was accidental. PMID:15935584

  8. Health and ergogenic effects of caffeine.

    PubMed Central

    Jacobson, B H; Kulling, F A

    1989-01-01

    The indiscriminate use of caffeine by people of all ages may present health hazards. The public at large needs to be more informed of the presence of caffeine in commonly consumed foods and beverages, particularly by infants, children and pregnant women. It is the responsibility of all consumers to investigate the caffeine content of suspected products so that intake may be objectively monitored. Although doubts still exist about the efficacy of caffeine as an ergogenic aid, particularly for exercise of high intensity and short duration, the IOC and the National Collegiate Athletic Association of the US have adopted bans on the use of caffeine to aid sport performance. Currently, both of these organizations prohibit the concentration of caffeine in urine to exceed 15 micrograms-ml-1. That is to say, only very large amounts of caffeine are not permitted at present. Additional research is needed to confirm or deny the contraindications presented by the ingestion of caffeine on a chronic basis. PMID:2659130

  9. Extraction of Caffeine--A Modern Experiment

    ERIC Educational Resources Information Center

    Cohen, Paul Shea; Smith, Eileen Patricia

    1969-01-01

    Describes an organic chemistry experiment suitable for high school students in second year or an advanced chemistry course. The techniques for the extraction and purification of caffeine from various household materials are described. Further experimentation with the extracted caffeine is suggested. (LC)

  10. Creatine and Caffeine: Considerations for Concurrent Supplementation.

    PubMed

    Trexler, Eric T; Smith-Ryan, Abbie E

    2015-12-01

    Nutritional supplementation is a common practice among athletes, with creatine and caffeine among the most commonly used ergogenic aids. Hundreds of studies have investigated the ergogenic potential of creatine supplementation, with consistent improvements in strength and power reported for exercise bouts of short duration (≤ 30 s) and high intensity. Caffeine has been shown to improve endurance exercise performance, but results are mixed in the context of strength and sprint performance. Further, there is conflicting evidence from studies comparing the ergogenic effects of coffee and caffeine anhydrous supplementation. Previous research has identified independent mechanisms by which creatine and caffeine may improve strength and sprint performance, leading to the formulation of multi-ingredient supplements containing both ingredients. Although scarce, research has suggested that caffeine ingestion may blunt the ergogenic effect of creatine. While a pharmacokinetic interaction is unlikely, authors have suggested that this effect may be explained by opposing effects on muscle relaxation time or gastrointestinal side effects from simultaneous consumption. The current review aims to evaluate the ergogenic potential of creatine and caffeine in the context of high-intensity exercise. Research directly comparing coffee and caffeine anhydrous is discussed, along with previous studies evaluating the concurrent supplementation of creatine and caffeine. PMID:26219105

  11. Feeling smart: Effects of caffeine and glucose on cognition, mood and self-judgment.

    PubMed

    Ullrich, Susann; de Vries, Yfke C; Kühn, Simone; Repantis, Dimitris; Dresler, Martin; Ohla, Kathrin

    2015-11-01

    During education and early career, young adults often face examinations and assessment centers. Coffee and energy drinks are convenient and commonly used to enhance or maintain performance in these situations. Whether these macronutrients improve performance in a demanding and drawn-out multi-task situation is not clear. Using double-blind, placebo-controlled studies, we set out to examine the effects of caffeine and glucose in an assessment center-like situation, under natural consumption conditions, in a group of young adults who were heterogeneous with respect to consumption patterns. We measured multi-task performance including logical thinking, processing speed, numeric and verbal memory, attention and the ability to concentrate, and mood over a two-hour period. Caffeine and glucose were administered in common beverages with appropriate placebo controls allowing the assessment of psychological effects of expectancy. Importantly, and in contrast to most previous studies, participants retained their habitual caffeine and sugar intake (studies 1 and 2) as this represents common behavior. Based on the bulk of literature, we hypothesized that (i) caffeine enhances attentional performance and mood, while performance in more complex tasks will remain unchanged, and that (ii) glucose enhances performance on memory tasks accompanied with negative mood. Our results provide evidence that neither caffeine nor glucose significantly influence cognitive performance when compared with placebo, water, or no treatment controls in a multi-task setting. Yet, caffeine and, by trend, placebo improve dispositions such that participants perceive preserved mental energy throughout the test procedure. These subjective effects were stronger after 24 h caffeine abstinence (study 3). Future studies will have to address whether these mood changes actually result in increased motivation during a challenging task. PMID:26320858

  12. Caffeine reduces dipyridamole-induced myocardial ischemia

    SciTech Connect

    Smits, P.; Aengevaeren, W.R.; Corstens, F.H.; Thien, T. )

    1989-10-01

    The mechanism of action of coronary vasodilation after dipyridamole may be based on inhibition of cellular uptake of circulating endogenous adenosine. Since caffeine has been reported to be a competitive antagonist of adenosine we studied the effect of caffeine on the outcome of dipiridamole-{sup 201}Tl cardiac imaging in one patient. During caffeine abstinence dipyridamole induced myocardial ischemia with down-slope ST depressions on the ECG, and reversible perfusion defects on the scintigrams. When the test was repeated 1 wk later on similar conditions, but now shortly after infusion of caffeine (4 mg/kg), the ECG showed nodepressions, and the scintigrams only slight signs of ischemia. We conclude that when caffeine abstinence is not sufficient, the widespread use of coffee and related products may be responsible for false-negative findings in dipyridamole-201Tl cardiac imaging.

  13. Effect of caffeine and alcohol on the toxicity and metabolism of methacrylonitrile in male Sprague-Dawley rats.

    PubMed

    Farooqui, Mohammed Y H; Trevino, Maria; Garcia, Isabella

    This study reports the toxicity and metabolism of methacrylonitrile (MeAN) in normal male Sprague-Dawley rats and those pre-treated with caffeine, alcohol or both. Rats were divided into groups often. One group received an oral dose by gavage of 6 % MeAN solution in corn oil (equivalent to 0.5 LD50). Other three groups of rats were pre-treated with alcohol (2 ml of 50% solution in water), caffeine (1 ml of 2% solution in water) or both alcohol and caffeine 12 hr before receiving MeAN dose by gavage. The rats were observed for mortality, cholinomimetic and central nervous system (CNS) effects and urinary dysfunction for 6 hr. The concentrations of cyanide, thiocyanate and glutathione (GSH) were determined in blood, liver, kidney and brain. Alcohol and alcohol + caffeine pre-treatment caused significant increase in cholinomimetic, CNS and urinary dysfunction effects of MeAN and mortality. However, caffeine alone pre-treatment protected rats from these effects. In the rats treated with MeAN alone and those pre-treated with alcohol and alcohol + caffeine the GSH concentrations significantly decreased in liver, brain and kidney. In the rats pre-treated with caffeine alone the concentrations of GSH were not significantly different from controls. In the rats treated with MeAN alone and those pretreated with alcohol and alcohol + caffeine the cyanide and thiocyanate concentrations increased in the blood and other organs up to 2-4 folds whereas in rats pre-treated with caffeine alone the concentrations of cyanide and thiocyanate were not significantly different from controls. Western Blot experiment showed CYP2E1 induction in rats pretreated with alcohol and MeAN. These results suggest that caffeine inhibited and alcohol enhanced toxicity and metabolism of MeAN. PMID:21469506

  14. Chronic fetal exposure to caffeine altered resistance vessel functions via RyRs-BKCa down-regulation in rat offspring

    PubMed Central

    Li, Na; Li, Yongmei; Gao, Qinqin; Li, Dawei; Tang, Jiaqi; Sun, Miao; Zhang, Pengjie; Liu, Bailin; Mao, Caiping; Xu, Zhice

    2015-01-01

    Caffeine modifies vascular/cardiac contractility. Embryonic exposure to caffeine altered cardiac functions in offspring. This study determined chronic influence of prenatal caffeine on vessel functions in offspring. Pregnant Sprague-Dawley rats (5-month-old) were exposed to high dose of caffeine, their offspring (5-month-old) were tested for vascular functions in mesenteric arteries (MA) and ion channel activities in smooth muscle cells. Prenatal exposure to caffeine increased pressor responses and vasoconstrictions to phenylephrine, accompanied by enhanced membrane depolarization. Large conductance Ca2+-activated K+ (BKCa) channels in buffering phenylephrine-induced vasoconstrictions was decreased, whole cell BKCa currents and spontaneous transient outward currents (STOCs) were decreased. Single channel recordings revealed reduced voltage/Ca2+ sensitivity of BKCa channels. BKCa α-subunit expression was unchanged, BKCa β1-subunit and sensitivity of BKCa to tamoxifen were reduced in the caffeine offspring as altered biophysical properties of BKCa in the MA. Simultaneous [Ca2+]i fluorescence and vasoconstriction testing showed reduced Ca2+, leading to diminished BKCa activation via ryanodine receptor Ca2+ release channels (RyRs), causing enhanced vascular tone. Reduced RyR1 was greater than that of RyR3. The results suggest that the altered STOCs activity in the caffeine offspring could attribute to down-regulation of RyRs-BKCa, providing new information for further understanding increased risks of hypertension in developmental origins. PMID:26277840

  15. Behavioral Management of Excessive Caffeine Consumption: Three Case Studies.

    ERIC Educational Resources Information Center

    Johnson-Greene, Douglas; And Others

    Although caffeine is seemingly harmless in ordinary daily intake, there has been increasing concern about the possible side effects of habitual caffeine ingestion. The excessive daily ingestion of caffeine in the form of coffee, soda pop, tea, and various medications may lead to a chronic disorder known as caffeinism. This study tested the…

  16. Marking Time

    ERIC Educational Resources Information Center

    Foster, Colin

    2011-01-01

    Teachers say that they would gladly teach a day in the classroom if at the end of the day they could leave and have no marking. There is a common staffroom perception that mathematics teachers have it easy when it comes to marking. In arts subjects, setting an essay can be a fairly straightforward matter--a one-line question may suffice--but…

  17. Dasatinib suppression of medulloblastoma survival and migration is markedly enhanced by combining treatment with the aurora kinase inhibitor AT9283

    PubMed Central

    Petersen, William; Liu, Jingbo; Yuan, Liangping; Zhang, Hongying; Schneiderjan, Matthew; Cho, Yoon-Jae; MacDonald, Tobey J.

    2014-01-01

    Medulloblastoma (MB) expresses Src kinase, while aurora kinase A overexpression correlates with poor survival. We thus investigated novel combination treatment with dasatinib and AT9283, inhibitors of Src and aurora kinase, respectively, on MB growth in vitro and in vivo. Treatment with each drug significantly reduced cell viability and combined treatment markedly potentiated this response. AT9283 induced p53 expression, autophagy, and G2/M cell-cycle arrest, while combined treatment induced S phase arrest. Dasatinib treatment caused tumor regression in vivo. Activated Src was detected in 44% MB analyzed. We conclude that further evaluation of this combination therapy for MB is highly warranted. PMID:25107642

  18. Maternal glucocorticoid elevation and associated blood metabonome changes might be involved in metabolic programming of intrauterine growth retardation in rats exposed to caffeine prenatally

    SciTech Connect

    Kou, Hao; Liu, Yansong; Liang, Gai; Huang, Jing; Hu, Jieqiong; Yan, You-e; Li, Xiaojun; Yu, Hong; He, Xiaohua; Zhang, Baifang; Zhang, Yuanzhen; Feng, Jianghua; Wang, Hui

    2014-03-01

    Our previous studies demonstrated that prenatal caffeine exposure causes intrauterine growth retardation (IUGR), fetuses are over-exposed to high levels of maternal glucocorticoids (GC), and intrauterine metabolic programming and associated metabonome alteration that may be GC-mediated. However, whether maternal metabonomes would be altered and relevant metabolite variations might mediate the development of IUGR remained unknown. In the present studies, we examined the dose- and time-effects of caffeine on maternal metabonome, and tried to clarify the potential roles of maternal GCs and metabonome changes in the metabolic programming of caffeine-induced IUGR. Pregnant rats were treated with caffeine (0, 20, 60 or 180 mg/kg · d) from gestational days (GD) 11 to 20, or 180 mg/kg · d caffeine from GD9. Metabonomes of maternal plasma on GD20 in the dose–effect study and on GD11, 14 and 17 in the time–course study were analyzed by {sup 1}H nuclear magnetic resonance spectroscopy, respectively. Caffeine administration reduced maternal weight gains and elevated both maternal and fetal corticosterone (CORT) levels. A negative correlation between maternal/fetal CORT levels and fetal bodyweight was observed. The maternal metabonome alterations included attenuated metabolism of carbohydrates, enhanced lipolysis and protein breakdown, and amino acid accumulation, suggesting GC-associated metabolic effects. GC-associated metabolite variations (α/β-glucoses, high density lipoprotein-cholesterol, β-hydroxybutyrate) were observed early following caffeine administration. In conclusion, prenatal caffeine exposure induced maternal GC elevation and metabonome alteration, and maternal GC and relevant discriminatory metabolites might be involved in the metabolic programming of caffeine-induced IUGR. - Highlights: • Prenatal caffeine exposure elevated maternal blood glucocorticoid levels. • Prenatal caffeine exposure altered maternal blood metabonomes. • Maternal

  19. Caffeine use and alexithymia in university students.

    PubMed

    Lyvers, Michael; Duric, Natalija; Thorberg, Fred Arne

    2014-01-01

    Abstract Alexithymia refers to difficulties with identifying, describing, and regulating one's own emotions. This trait dimension has been linked to risky or harmful use of alcohol and illicit drugs; however, the most widely used psychoactive drug in the world, caffeine, has not been examined previously in relation to alexithymia. The present study assessed 106 male and female university students aged 18-30 years on their caffeine use in relation to several traits, including alexithymia. The 18 participants defined as alexithymic based on their Toronto Alexithymia Scale (TAS-20) scores reported consuming nearly twice as much caffeine per day as did non-alexithymic or borderline alexithymic participants. They also scored significantly higher than controls on indices of frontal lobe dysfunction as well as anxiety symptoms and sensitivity to punishment. In a hierarchical linear regression model, sensitivity to punishment negatively predicted daily caffeine intake, suggesting caffeine avoidance by trait-anxious individuals. Surprisingly, however, TAS-20 alexithymia scores positively predicted caffeine consumption. Possible reasons for the positive relationship between caffeine use and alexithymia are discussed, concluding that this outcome is tentatively consistent with the hypo-arousal model of alexithymia. PMID:25188705

  20. Caffeine and sports activity: a review.

    PubMed

    Nehlig, A; Debry, G

    1994-07-01

    Potential ergogenic effects of caffeine at the cellular level are mediated by three main mechanisms of action which are: intracellular mobilization of calcium from sarcoplasmic reticulum and increased sensitivity of myofibrilles to calcium; inhibition of phosphodiesterases leading to an increase in cyclic-3',5'-adenosine monophosphate (cAMP) in various tissues including muscle; and the antagonism at the level of adenosine receptors, mainly in the central nervous system. The main mechanism of action of caffeine at the level usually encountered in vivo after the ingestion of a few cups of coffee is undoubtedly linked to the antagonism of caffeine at adenosine receptors. Caffeine also increases production of plasma catecholamines that allow the body to adapt to the stress created by physical exercise. Catecholamine production increases probably, in turn, the availability of free fatty acids as muscle substrates during work, thus allowing glycogen sparing. Caffeine is able to increase muscle contractility, has no ergogenic effect on intense exercise of brief duration, but can improve the time before exhaustion. Caffeine is also able to improve physical performance and endurance during prolonged activity of submaximal intensity. Glycogen sparing resulting from increased rate of lipolysis could contribute to the prolonged time to exhaustion. Finally, tolerance to the methylxanthine should be taken into account when an athlete wants to draw any benefit from caffeine absorption prior to a sports event. PMID:7960313

  1. Caffeine relaxes smooth muscle through actin depolymerization.

    PubMed

    Tazzeo, Tracy; Bates, Genevieve; Roman, Horia Nicolae; Lauzon, Anne-Marie; Khasnis, Mukta D; Eto, Masumi; Janssen, Luke J

    2012-08-15

    Caffeine is sometimes used in cell physiological studies to release internally stored Ca(2+). We obtained evidence that caffeine may also act through a different mechanism that has not been previously described and sought to examine this in greater detail. We ruled out a role for phosphodiesterase (PDE) inhibition, since the effect was 1) not reversed by inhibiting PKA or adenylate cyclase; 2) not exacerbated by inhibiting PDE4; and 3) not mimicked by submillimolar caffeine nor theophylline, both of which are sufficient to inhibit PDE. Although caffeine is an agonist of bitter taste receptors, which in turn mediate bronchodilation, its relaxant effect was not mimicked by quinine. After permeabilizing the membrane using β-escin and depleting the internal Ca(2+) store using A23187, we found that 10 mM caffeine reversed tone evoked by direct application of Ca(2+), suggesting it functionally antagonizes the contractile apparatus. Using a variety of molecular techniques, we found that caffeine did not affect phosphorylation of myosin light chain (MLC) by MLC kinase, actin-filament motility catalyzed by MLC kinase, phosphorylation of CPI-17 by either protein kinase C or RhoA kinase, nor the activity of MLC-phosphatase. However, we did obtain evidence that caffeine decreased actin filament binding to phosphorylated myosin heads and increased the ratio of globular to filamentous actin in precontracted tissues. We conclude that, in addition to its other non-RyR targets, caffeine also interferes with actin function (decreased binding by myosin, possibly with depolymerization), an effect that should be borne in mind in studies using caffeine to probe excitation-contraction coupling in smooth muscle. PMID:22683573

  2. Caffeine in your drink: natural or synthetic?

    PubMed

    Zhang, Lijun; Kujawinski, Dorothea M; Federherr, Eugen; Schmidt, Torsten C; Jochmann, Maik A

    2012-03-20

    Owing to possible adulteration and health concerns, it is important to discriminate between natural and synthetic food ingredients. A new method for compound-specific isotope analysis (CSIA) by coupling high-temperature reversed-phase liquid chromatography to isotope ratio mass spectrometry (HT-RPLC/IRMS) was developed for discrimination of natural and synthetic caffeine contained in all types of drinks. The analytical parameters such as stationary phase, column inner diameter, and column temperature were optimized for the separation of caffeine directly from drinks (without extraction). On the basis of the carbon isotope analysis of 42 natural caffeine samples including coffee beans, tea leaves, guaraná powder, and maté leaves, and 20 synthetic caffeine samples from different sources by high-temperature reversed-phase liquid chromatography coupled to isotope ratio mass spectrometry, it is concluded that there are two distinguishable groups of caffeine δ(13)C-values: one between -25 and -32‰ for natural caffeine, and the other between -33 and -38‰ for synthetic caffeine. Isotope analysis by HT-RPLC/IRMS has been applied to identify the caffeine source in 38 drinks. Four mislabeled products were detected due to added but nonlabeled synthetic caffeine with δ(13)C-values lower than -33‰. This work is the first application of HT-RPLC/IRMS to real-world food samples, which showed several advantages: simple sample preparation (only dilution), high throughput, long-term column stability, and high precision of δ(13)C-value. Thus, HT-RPLC/IRMS can be a very promising tool in stable isotope analysis of nonvolatile compounds. PMID:22339647

  3. Caffeine alters the behavioural and body temperature responses to mephedrone without causing long-term neurotoxicity in rats.

    PubMed

    Shortall, Sinead E; Green, A Richard; Fone, Kevin Cf; King, Madeleine V

    2016-07-01

    Administration of caffeine with 3,4-methylenedioxymethamphetamine (MDMA) alters the pharmacological properties of MDMA in rats. The current study examined whether caffeine alters the behavioural and neurochemical effects of mephedrone, which has similar psychoactive effects to MDMA. Rats received either saline, mephedrone (10 mg/kg), caffeine (10 mg/kg) or combined caffeine and mephedrone intraperitoneally twice weekly on consecutive days for three weeks. Locomotor activity (days 1 and 16), novel object discrimination (NOD, day 2), elevated plus maze (EPM) exploration (day 8), rectal temperature changes (day 9) and pre-pulse inhibition (PPI) of acoustic startle response (day 15) were assessed. Seven days after the final injection, brain regions were collected for the measurement of 5-hydroxytryptamine (5-HT), dopamine and their metabolites. Combined caffeine and mephedrone further enhanced the locomotor response observed following either drug administered alone, and converted mephedrone-induced hypothermia to hyperthermia. Co-administration also abolished mephedrone-induced anxiogenic response on the EPM, but had no effect on NOD or PPI. Importantly, no long-term neurotoxicity was detected following repeated mephedrone alone or when co-administered with caffeine. In conclusion, the study suggests a potentially dangerous effect of concomitant caffeine and mephedrone, and highlights the importance of taking polydrug use into consideration when investigating the acute adverse effect profile of popular recreational drugs. PMID:27257032

  4. Caffeine induced changes in cerebral circulation

    SciTech Connect

    Mathew, R.J.; Wilson, W.H.

    1985-09-01

    While the caffeine induced cerebral vasoconstriction is well documented, the effects of oral ingestion of the drug in a dose range comparable to the quantities in which it is usually consumed and the intensity and duration of the associated reduction in cerebral circulation are unknown. Cerebral blood flow was measured via the TTXenon inhalation technique before and thirty and ninety minutes after the oral administration of 250 mg of caffeine or a placebo, under double-blind conditions. Caffeine ingestion was found to be associated with significant reductions in cerebral perfusion thirty and ninety minutes later. The placebo group showed no differences between the three sets of cerebral blood flow values.

  5. Quantitative HPLC Analysis of an Analgesic/Caffeine Formulation: Determination of Caffeine

    NASA Astrophysics Data System (ADS)

    Ferguson, Glenda K.

    1998-04-01

    A modern high performance liquid chromatography (HPLC) laboratory experiment which entails the separation of acetaminophen, aspirin, and caffeine and the quantitative assay of caffeine in commercial mixtures of these compounds has been developed. Our HPLC protocol resolves these compounds in only three minutes with a straightforward chromatographic apparatus which consists of a C-18 column, an isocratic mobile phase, UV detection at 254 nm, and an integrator; an expensive, sophisticated system is not required. The separation is both repeatable and rapid. Moreover, the experiment can be completed in a single three-hour period. The experiment is appropriate for any chemistry student who has completed a minimum of one year of general chemistry and is ideal for an analytical or instrumental analysis course. The experiment detailed herein involves the determination of caffeine in Goody's Extra Strength Headache Powders, a commercially available medication which contains acetaminophen, aspirin, and caffeine as active ingredients. However, the separation scheme is not limited to this brand of medication nor is it limited to caffeine as the analyte. With only minor procedural modifications, students can simultaneously quantitate all of these compounds in a commercial mixture. In our procedure, students prepare a series of four caffeine standard solutions as well as a solution from a pharmaceutical analgesic/caffeine mixture, chromatographically analyze each solution in quadruplicate, and plot relative average caffeine standard peak area versus concentration. From the mathematical relationship that results, the concentration of caffeine in the commercial formulation is obtained. Finally, the absolute standard deviation of the mean concentration is calculated.

  6. Stretch Marks

    MedlinePlus

    ... changes that can go with bodybuilding. People who use steroid-containing skin creams or ointments (such as hydrocortisone) for more than a few weeks may also get stretch marks. So might people who have to ... surgeon. These doctors may use one of many types of treatments — from actual ...

  7. Beneficial synergistic effects of concurrent treatment with theanine and caffeine against cerebral ischemia-reperfusion injury in rats.

    PubMed

    Sun, Lingyan; Tian, Xia; Gou, Lingshan; Ling, Xin; Wang, Ling; Feng, Yan; Yin, Xiaoxing; Liu, Yi

    2013-07-01

    Theanine and caffeine, 2 naturally occurring components in tea, have repeatedly been shown to deliver unique cognitive benefits when consumed in combination. In this study, we assessed the beneficial synergistic effects of concurrent treatment with theanine and caffeine against cerebral damage in rats. Theanine and caffeine had no effect on physiological variables, including pH, partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2), mean arterial blood pressure, plasma glucose, or regional cerebral blood flow. Treatment with theanine (1 mg/kg body mass, intraperitoneal injection) alone significantly reduced cerebral infarction induced by cerebral ischemia-reperfusion, but caffeine (10 mg/kg, intravenous administration) alone only had a marginal effect. However, the combination of theanine plus caffeine resulted in a significant reduction of cerebral infarction and brain edema compared with theanine monotherapy. Meanwhile, increased malondialdehyde levels as well as decreased superoxide dismutase activity, glutathione peroxidase activity, and glutathione levels observed in the cerebral cortex after cerebral ischemia-reperfusion were significantly ameliorated by the combination therapy. Furthermore, the elevated inflammatory response levels observed in the cortex after cerebral ischemia-reperfusion were markedly attenuated by the combined treatment. Thus, it is suggested that the neuroprotective potential of a combination therapy with theanine and caffeine against cerebral ischemia-reperfusion is partly ascribed to their antioxidant and anti-inflammatory properties. PMID:23826680

  8. A Simple Route to Reduced Graphene Oxide-Draped Nanocomposites with Markedly Enhanced Visible-Light Photocatalytic Performance.

    PubMed

    Liu, Xueqin; Yang, Jianbo; Zhao, Wen; Wang, Yang; Li, Zhen; Lin, Zhiqun

    2016-08-01

    Nanocomposites (denoted RGO/ZnONRA) comprising reduced graphene oxide (RGO) draped over the surface of zinc oxide nanorod array (ZnONRA) were produced via a simple low-temperature route, dispensing with the need for hydrothermal growth, electrochemical deposition or other complex treatments. The amount of deposited RGO can be readily tuned by controlling the concentration of graphene oxide (GO). Interestingly, the addition of Sn(2+) not only enables the reduction of GO, but also functions as a bridge that connects the resulting RGO and ZnONRA. Remarkably, the incorporation of RGO improves the visible-light absorption and reduces the bandgap of ZnO, thereby leading to the markedly improved visible-light photocatalytic performance. Moreover, RGO/ZnONRA nanocomposites exhibit a superior stability as a result of the surface protection of ZnONRA by RGO. The mechanism on the improved photocatalytic performance based on the cophotosensitizations under the visible-light irradiation has been proposed. This simple yet effective route to the RGO-decorated semiconductor nanocomposites renders the better visible-light utilization, which may offer great potential for use in photocatalytic degradation of organic pollutants, solar cells, and optoelectronic materials and devices. PMID:27322494

  9. The effects of Red Bull energy drink compared with caffeine on cycling time-trial performance.

    PubMed

    Quinlivan, Alannah; Irwin, Christopher; Grant, Gary D; Anoopkumar-Dukie, Sheilandra; Skinner, Tina; Leveritt, Michael; Desbrow, Ben

    2015-10-01

    This study investigated the ergogenic effects of a commercial energy drink (Red Bull) or an equivalent dose of anhydrous caffeine in comparison with a noncaffeinated control beverage on cycling performance. Eleven trained male cyclists (31.7 ± 5.9 y 82.3 ± 6.1 kg, VO2max = 60.3 ± 7.8 mL · kg-1 · min-1) participated in a double-blind, placebo-controlled, crossover-design study involving 3 experimental conditions. Participants were randomly administered Red Bull (9.4 mL/kg body mass [BM] containing 3 mg/kg BM caffeine), anhydrous caffeine (3 mg/kg BM given in capsule form), or a placebo 90 min before commencing a time trial equivalent to 1 h cycling at 75% peak power output. Carbohydrate and fluid volumes were matched across all trials. Performance improved by 109 ± 153 s (2.8%, P = .039) after Red Bull compared with placebo and by 120 ± 172 s (3.1%, P = .043) after caffeine compared with placebo. No significant difference (P > .05) in performance time was detected between Red Bull and caffeine treatments. There was no significant difference (P > .05) in mean heart rate or rating of perceived exertion among the 3 treatments. This study demonstrated that a moderate dose of caffeine consumed as either Red Bull or in anhydrous form enhanced cycling time-trial performance. The ergogenic benefits of Red Bull energy drink are therefore most likely due to the effects of caffeine, with the other ingredients not likely to offer additional benefit. PMID:25710190

  10. Caffeine Effects on ERP Components and Performance in an Equiprobable Auditory Go/NoGo Task.

    PubMed

    Barry, Robert J; De Blasio, Frances M; Cave, Adele E

    2014-09-01

    Background: Research has reliably demonstrated that caffeine produces a general increase in physiological arousal in humans, but we previously failed to obtain the expected arousal-based changes in manually quantified event-related potential (ERP) components in response to the stimuli in a simple Go/NoGo task. Methods: A single oral dose of caffeine (250 mg) was used in a randomized double-blind placebo-controlled repeated-measures cross-over study. Adult participants (N=24) abstained from caffeine for 4 hours before each of two sessions, approximately 1 week apart. An equiprobable auditory Go/NoGo task was used, with a random mix of 75 tones at 1,000 Hz and 75 at 1,500 Hz. All tones were 50 ms duration (rise/fall time 5 ms) at 60 dB SPL, with a fixed stimulus-onset asynchrony of 1100 ms. Principal component analysis (a form of factor analysis) was used to quantify orthogonal ERP components. Results: ERP components reflected the different sequential processing of each stimulus type in this paradigm, replicating previous results. Caffeine was associated with a reduction in reaction time and fewer omission errors. The major ERP effects of caffeine were apparent as a slightly enhanced Processing Negativity and larger P3b amplitudes to Go stimuli. There were few effects on components to NoGo stimuli. Conclusions: The results confirm our previous findings that caffeine improves aspects of the differential processing related to response production and task performance, but may be interpreted as supporting the simple amplification of ERP component amplitudes predicted by the general arousal induced by caffeine. PMID:25229010

  11. Caffeinated alcohol beverages: a public health concern.

    PubMed

    Attwood, Angela S

    2012-01-01

    Consumption of alcohol mixed with caffeinated energy drinks is becoming popular, and the number of pre-mixed caffeinated alcohol products on the worldwide market is increasing. There is public health concern and even occasional legal restriction relating to these drinks, due to associations with increased intoxication and harms. The precise nature and degree of the pharmacological relationship between caffeine and alcohol is not yet elucidated, but it is proposed that caffeine attenuates the sedative effects of alcohol intoxication while leaving motor and cognitive impairment unaffected. This creates a potentially precarious scenario for users who may underestimate their level of intoxication and impairment. While legislation in some countries has restricted production or marketing of pre-mixed products, many individuals mix their own energy drink-alcohol 'cocktails'. Wider dissemination of the risks might help balance marketing strategies that over-emphasize putative positive effects. PMID:22645036

  12. The Effects of Caffeine on Hyperactive Children

    ERIC Educational Resources Information Center

    Firestone, Philip; And Others

    1978-01-01

    The psychological, physiological, and behavioral effects of a 2-week regimen of 300 mg of caffeine on 20 hyperactive males between the ages of 5 and 12 years were examined, using a double-blind crossover format. (Author)

  13. Caffeine in surface and wastewaters in Barbados, West Indies.

    PubMed

    Edwards, Quincy A; Kulikov, Sergei M; Garner-O'Neale, Leah D

    2015-01-01

    Caffeine, a purine alkaloid drug, has been recognized as a contaminant of water bodies in various climatic regions, however, these environmental caffeine concentrations are the first to be reported in the tropical Caribbean. The major objective of this study was to develop an improved method to extract caffeine from surface and wastewaters in the warm Caribbean environment and measure caffeine concentrations in highly populated areas in Barbados. Caffeine was extracted from water via solid phase extraction (SPE); the acidified water samples were loaded onto C-18 cartridges and eluted with pure chloroform. The extracted caffeine was quantified using gas chromatography - mass spectroscopy - multiple reaction monitoring (GC-MS/MS-MRM). Method detection limits of 0.2 ng L(-1) from 1 L water samples were achieved. Caffeine was detected in all environmental water samples investigated. The concentrations of caffeine in surface waters were detected in the range 0.1 - 6.9 μg L(-1). The two wastewater treatment plants, primary and secondary treatment systems, significantly differed in their ability to eliminate caffeine in the raw sewage (38% and 99% caffeine removal efficiencies respectively). Thus, it may be essential to employ secondary treatment to effectively remove caffeine from wastewater systems in Barbados. Caffeine in water bodies are principally attributed to anthropogenic sources as caffeine-producing plants are not commonly grown on the island of Barbados. The study also shows the recalcitrance of caffeine to hydrolytic degradation. PMID:25729634

  14. Hydrophobic Mutagenesis and Semi-rational Engineering of Arginine Deiminase for Markedly Enhanced Stability and Catalytic Efficiency.

    PubMed

    Jamil, Serwanja; Liu, Meng-Han; Liu, Yong-Mei; Han, Rui-Zhi; Xu, Guo-Chao; Ni, Ye

    2015-07-01

    Due to its systemic arginine degradation, arginine deiminase (ADI) has attracted attentions as an anti-tumor drug. Its low activity at physiological conditions among other limitations has necessitated its engineering for improved properties. The present study describes the hydrophobic mutagenesis and semi-rational engineering of ADI from Pseudomonas plecoglossicida (PpADI). Using an improved ADI variant M13 (D38H/A128T/E296K/H404R/I410L) as parent, site saturation mutagenesis at position 162 resulted in an over 20 % increase in protein solubility. Compared with M13 (15.23 U/mg), mutants M13-2 (M13+S245D) and M13-5 (M13+R243L) exhibited enhanced specific activity of 21.19 and 31.20 U/mg at physiological conditions. M13-5 displayed enhanced substrate specificity with a dramatic reduction in its K m value (from 0.52 to 0.16 mM). It is speculated that the improvements in M13-5 could mainly be attributed to the enhanced structural stability due to an R243L substitution. The hydrophobic contribution of Leu 243 was supported by mutant M13-9 (M13+A276W) generated based on the hydrophobic mutagenesis concept. M13-9 showed a specific activity of 18.68 U/mg, as well as remarkable thermal and pH stability. It retained over 90 % activity over pH range from 4.5 to 8.5. At 60 °C, the half-life of M13-9 was enhanced from 4 to 17.5 min in comparison with M13, and its specific activity at 62 °C (93.0 U/mg) was approximately fivefold of that determined at 37 °C. Our results suggest that the increased hydrophobicity around the active regions of PpADI might be crucial in improving its structural stability and ultimately catalytic efficiency. PMID:26041055

  15. Characterization of individuals seeking treatment for caffeine dependence.

    PubMed

    Juliano, Laura M; Evatt, Daniel P; Richards, Brian D; Griffiths, Roland R

    2012-12-01

    Previous investigations have identified individuals who meet criteria for Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000) substance dependence as applied to caffeine, but there is little research on treatments for caffeine dependence. This study aimed to thoroughly characterize individuals who are seeking treatment for problematic caffeine use. Ninety-four individuals who identified as being psychologically or physically dependent on caffeine, or who had tried unsuccessfully to modify caffeine consumption participated in a face-to-face diagnostic clinical interview. They also completed measures concerning caffeine use and quitting history, reasons for seeking treatment, and standardized self-report measures of psychological functioning. Caffeine treatment seekers (mean age 41 years, 55% women) consumed an average of 548 mg caffeine per day. The primary source of caffeine was coffee for 50% of the sample and soft drinks for 37%. Eighty-eight percent reported prior serious attempts to modify caffeine use (mean 2.7 prior attempts), and 43% reported being advised by a medical professional to reduce or eliminate caffeine. Ninety-three percent met criteria for caffeine dependence when generic DSM-IV-TR substance dependence criteria were applied to caffeine use. The most commonly endorsed criteria were withdrawal (96%), persistent desire or unsuccessful efforts to control use (89%), and use despite knowledge of physical or psychological problems caused by caffeine (87%). The most common reasons for wanting to modify caffeine use were health-related (59%) and not wanting to be dependent on caffeine (35%). This investigation reveals that there are individuals with problematic caffeine use who are seeking treatment and suggests that there is a need for effective caffeine dependence treatments. PMID:22369218

  16. Prenatal Caffeine Exposure Impairs Pregnancy in Rats

    PubMed Central

    Yadegari, Maryam; Khazaei, Mozafar; Anvari, Morteza; Eskandari, Mohadeseh

    2016-01-01

    Background In recent years, concerns have been raised about human reproductive disorders. Caffeine consumption is increasing by the world’s population and there is a relationship between caffeine intake and adverse reproductive outcomes. The aim of this study was to evaluate the effects of caffeine on implantation sites, number of live births, birth weight, crown-rump length (CRL) and abnormality in pregnant rats. Materials and Methods In this experimental study, 40 female albino rats (170-190 g) were randomly divided into two experimental and two control groups (n=10/each group). In both experimental groups, animals received caffeine intraperitoneally (IP: 150 mg/kg/day) on days 1-5 of pregnancy. In experimental group 1, treated animals were euthanized on day 7of pregnancy and the number of implantation sites was counted. In experimental group 2, treated animals maintained pregnant and after delivery, the number of live births, birth weight, CRL and abnormality of neonates were investigated. In control group, animals received IP injections of distilled water. Data were analyzed by independent t test. Results Results showed that administration of caffeine significantly decreased the number of implantation sites, number of live births and CRL as compared with control group (P<0.05). There were no significant differences regarding birth weight and abnormality of neonate rats between experimental and control groups. Conclusion These results suggest that caffeine caused anti-fertility effect and significantly decreased CRL in neonate rats. PMID:26985345

  17. Effects of caffeine on human health.

    PubMed

    Nawrot, P; Jordan, S; Eastwood, J; Rotstein, J; Hugenholtz, A; Feeley, M

    2003-01-01

    Caffeine is probably the most frequently ingested pharmacologically active substance in the world. It is found in common beverages (coffee, tea, soft drinks), in products containing cocoa or chocolate, and in medications. Because of its wide consumption at different levels by most segments of the population, the public and the scientific community have expressed interest in the potential for caffeine to produce adverse effects on human health. The possibility that caffeine ingestion adversely affects human health was investigated based on reviews of (primarily) published human studies obtained through a comprehensive literature search. Based on the data reviewed, it is concluded that for the healthy adult population, moderate daily caffeine intake at a dose level up to 400 mg day(-1) (equivalent to 6 mg kg(-1) body weight day(-1) in a 65-kg person) is not associated with adverse effects such as general toxicity, cardiovascular effects, effects on bone status and calcium balance (with consumption of adequate calcium), changes in adult behaviour, increased incidence of cancer and effects on male fertility. The data also show that reproductive-aged women and children are 'at risk' subgroups who may require specific advice on moderating their caffeine intake. Based on available evidence, it is suggested that reproductive-aged women should consume caffeine per day (equivalent to 4.6 mg kg(-1) bw day(-1) for a 65-kg person) while children should consume

  18. Supraadditive formation of micronuclei in preimplantation mouse embryos in vitro after combined treatment with X-rays and caffeine

    SciTech Connect

    Mueller, W.U.S.; Streffer, C.; Wurm, R.

    1985-01-01

    The influence of caffeine (0.1 or 2 mM), X-rays (0.24 Gy or 0.94 Gy, or of a combination of both on the formation of micronuclei in early stages of preimplantation mouse embryos in vitro was studied. X-rays as well as caffeine induced micronuclei. The dose-effect curve after irradiation was linear for the dose range measured. Caffeine did not induce micronuclei if the concentration was 1 mM or less; between 1 mM and 7 mM, however, there was a linear increase in the number of micronuclei. A considerable enhancement of the number of radiation-induced micronuclei was observed when irradiation of the embryos was followed by a treatment with caffeine. Not only was the sum of the single effects exceeded by the combination effects, but the combination results even lay in the range of supraadditivity of the envelope of additivity.

  19. [Caffeine in nutrition. Article 1. Consumption with food and regulation].

    PubMed

    Bessonov, V V; Khanferyan, R A

    2015-01-01

    The article presents a review of the literature data on the effect of caffeine contained in a variety of foods on the functions of human, it presents the modern international legal regulatory rules in the consumption of caffeine, and caffeine consumption rules corresponding to the technical regulations of the Customs Union (Russian Federation, Kazakhstan, Belaruss). It describes the sources of caffeine in the traditional diet and its consumption, safety evaluation in connection with the acute and chronic caffeine consumption and the value of caffeine as an ingredient in soft drinks tonic. PMID:26852540

  20. Degradation of exogenous caffeine by Populus alba and its effects on endogenous caffeine metabolism.

    PubMed

    Pierattini, Erika C; Francini, Alessandra; Raffaelli, Andrea; Sebastiani, Luca

    2016-04-01

    This is the first study reporting the presence of endogenous caffeine, theobromine, and theophylline in all organs of poplar plants. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was used in order to evaluate the uptake, translocation, and metabolism of caffeine-(trimethyl-(13)C) in Populus alba L. Villafranca clone grown in hydroponic conditions. We investigated the remediation of caffeine since it is one of the most widely consumed drugs and it is frequently detected in wastewater treatment plant effluents, surface water, and groundwater worldwide. Our results demonstrated that poplar can absorb and degrade exogenous caffeine without negative effects on plant health. Data showed that concentrations of all endogenous compounds varied depending on caffeine-(trimethyl-(13)C) treatments. In particular, in control conditions, endogenous caffeine, theobromine, and theophylline were mainly distributed in roots. On the other hand, once caffeine-(trimethyl-(13)C) was provided, this compound and its dimethy-(13)C metabolites are mainly localized at leaf level. In conclusion, our results support the possible use of Villafranca clone in association with other water treatment systems in order to complete the process of caffeine remediation. PMID:26681326

  1. Fluorescence Based Turn-on Probe for the Determination of Caffeine Using Europium-Tetracycline as Energy Transfer Complex.

    PubMed

    Nanjundaiah, Shwetha; Krishna, Honnur; Bhatt, Praveena

    2016-05-01

    The study describes a simple and sensitive fluorometric sensor based on the enhancement of fluorescence intensity of Europium ion (Eu(3+)) - tetracycline (TC) charge transfer complex on addition of caffeine. The Eu(3+)-TC ternary complex has a characteristic emission peak at 615 nm (λex = 375 nm), the intensity of which increases with increase in concentration of caffeine. The caffeine sensor assay was found to be linear in the range of 0.0515 mM to 51.5 mM. The limit of detection and quantification were found to be 0.0515 mM and 0.382 mM, respectively. A caffeine recovery of 90 to 110 % in biological samples (serum and urine) indicated minimal interference by commonly present excipients in the samples. Rosenthal plots to calculate the binding capacity of caffeine with the Eu(3+)- TC complex revealed an association constant (K) of 238 x 10(3) L/mol and binding number (N) of 1.9. Bland-Altman plot comparing the developed assay and HPLC showed good agreement between values obtained by both the methods. The proposed fluorescent chemical sensor is a rapid and convenient method to determine caffeine with excellent recovery and low detection limit. The probable reaction mechanism for the formation of the turn on fluorescent probe enhancer is discussed. PMID:27063870

  2. Nanoimmunoliposome Delivery of Superparamagnetic Iron Oxide Markedly Enhances Targeting and Uptake in Human Cancer Cells In Vitro and In Vivo

    PubMed Central

    Yang, Chengli; Rait, Antonina; Pirollo, Kathleen F.; Dagata, John A.; Farkas, Natalia; Chang, Esther H.

    2008-01-01

    To circumvent the problem of reduction of the supermagnetic properties of superparamagnetic iron oxide (SPIO) nanoparticles after chemical modification to conjugate targeting molecules, we have adapted a tumor-targeting nanoimmunoliposome platform technology (scL) to encapsulate and deliver SPIO (scL-SPIO) in vitro and in vivo without chemical modification. Scanning probe microscopy, confocal microscopy, and Prussian blue staining were employed to analyze the scL-SPIO nanoparticles and assess intracellular uptake and distribution of SPIO in vitro. In vivo targeting and tumor-specific uptake of scL-SPIO was examined using fluorescent-labeled SPIO. We demonstrated that SPIO encapsulation in the scL complex results in approximately an 11 fold increase in SPIO uptake in human cancer cells in vitro, with distribution to cytoplasm and nucleus. Moreover, the scL nanocomplex specifically and efficiently delivered SPIO into tumor cells after systemic administration, demonstrating the potential of this approach to enhance local tumor concentration and the utility of SPIO for clinical applications. PMID:18676207

  3. On your marks, get set, go!-lessons from the UK in enhancing employability of graduates and postgraduates.

    PubMed

    Fahnert, Beatrix

    2015-10-01

    Employers expect graduates and postgraduates to demonstrate their education through more than good grades. Learning activities that develop subject skills during formalized programmes of undergraduate and postgraduate study also develop employability skills, if the curriculum is suitably aligned, and developmental planning is supported. Only little extra provision is required, but all development needs to be explicitly signposted to the learner, and the curriculum should be developed in consultation with employers. This review aims to raise awareness of current issues in the context of enhancing employability that arise from an increased global competition on the job market and the expectation of the Higher Education sector to produce work-ready graduates and postgraduates that are well equipped to adapt to a quickly changing work environment particularly due to transferable skills. In the context of lessons from the UK, these current issues and employability are discussed, and approaches to Personal Development Planning that prepare students for lifelong learning and that enable communicating and evidencing achievement are addressed. Issues specific to postgraduates, how actual work experience should be maximized as well as other career influences such as learned societies and social networking are highlighted. PMID:26337154

  4. Reversal of caffeine withdrawal by ingestion of a soft beverage.

    PubMed

    Watson, J M; Lunt, M J; Morris, S; Weiss, M J; Hussey, D; Kerr, D

    2000-05-01

    Followlng regular use, acute cessation of caffeine is associated with a characteristic withdrawal syndrome. Despite this, caffeine remains popular with its consumers. The aim of this study was to examine the physiologic and psychologic effects of small caffeine doses, administered in the form of a market-leading soft drink, on healthy women who were acutely withdrawn from caffeine. After 48-h abstinence and overnight fast, 11 healthy (22 to 40 years) female volunteers, all regular caffeine users (daily consumption 143 to 773 mg) consumed using a double-blind. randomized, controlled cross-over design either 2 tins of regular or caffeine-free Diet Coke. On both visits a Mars bar was eaten to prevent hypoglycaemia. Thus, the caffeine load was 76 or 10 mg respectively. Following ingestion of regular Diet Coke, there was a l0% fall in middle cerebral artery velocity (95% CI [6%-l4%], p < 0.005 versus caffeine free) and improvement in feelings of pleasure (p < 0.046) and energy (p < 0.037). Intellectual function (4-choice reaction time) was unaffected by caffeine status. On both visits, ingestion of Diet Coke induced a pressor response (maximum rise in systolic pressure +15+/- 2 mm Hg with caffeine and +l2 +/- 2 mm Hg with caffeine-free beverage, both p < 0.001 compared with baseline). In conclusion, in women acutely withdrawn from caffeine, ingestion of a popular soft beverage containing modest amounts of caffeine is associated with demonstrable physiologic and psychologic effects. PMID:10837839

  5. Mechanism of Nanotization-Mediated Improvement in the Efficacy of Caffeine Against 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine-Induced Parkinsonism.

    PubMed

    Singhal, Naveen Kumar; Agarwal, Swati; Bhatnagar, Priyanka; Tiwari, Manindra Nath; Tiwari, Shashi Kant; Srivastava, Garima; Kumar, Pradeep; Brashket, Seth; Patel, Devendra Kumar; Chaturvedi, Rajnish Kumar; Singh, Mahendra Pratap; Gupta, Kailash Chand

    2015-12-01

    The study aimed to measure the neuroprotective efficacy of caffeine-encapsulated poly(lactic-co-glycolic acid) (PLGA) nanoparticles over bulk and to delineate the mechanism of improvement in efficacy both in vitro and in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of Parkinsonism. Caffeine-encapsulated PLGA nanoparticles exhibited more pronounced increase in the endurance of dopaminergic neurons, fibre outgrowth and expression of tyrosine hydroxylase (TH) and growth-associated protein-43 (GAP-43) against 1-methyl-4-phenylpyridinium (MPP+)-induced alterations in vitro. Caffeine-encapsulated PLGA nanoparticles also inhibited MPP(+)-mediated nuclear translocation of nuclear factor-kappa B (NF-κB) and augmented protein kinase B phosphorylation more potentially than bulk counterpart. Conversely, MPTP reduced the striatal dopamine and its metabolites and nigral TH immunoreactivity whereas augmented the nigral microglial activation and nigrostriatal lipid peroxidation and nitrite content, which were shifted towards normalcy by caffeine. The modulations were more evident in caffeine-encapsulated PLGA nanoparticles treated animals as compared with bulk. Moreover, the striatal caffeine and its metabolites were found to be significantly higher in caffeine-encapsulated PLGA nanoparticles-treated mice as compared with bulk. The results thus suggest that nanotization improves the protective efficacy of caffeine against MPTP-induced Parkinsonism owing to enhanced bioavailability, inhibition of the nuclear translocation of NF-κB and activation of protein kinase B phosphorylation. PMID:26510314

  6. Marked enhancement of lysosomal targeting and efficacy of ErbB2-targeted drug delivery by HSP90 inhibition

    PubMed Central

    Mohapatra, Bhopal; Luan, Haitao; Soni, Kruti; Zhang, Jinjin; Storck, Matthew A.; Feng, Dan; Bielecki, Timothy A.; Band, Vimla; Cohen, Samuel M.; Bronich, Tatiana K.; Band, Hamid

    2016-01-01

    Targeted delivery of anticancer drugs to tumor cells using monoclonal antibodies against oncogenic cell surface receptors is an emerging therapeutic strategy. These strategies include drugs directly conjugated to monoclonal antibodies through chemical linkers (Antibody-Drug Conjugates, ADCs) or those encapsulated within nanoparticles that in turn are conjugated to targeting antibodies (Antibody-Nanoparticle Conjugates, ANPs). The recent FDA approval of the ADC Trastuzumab-TDM1 (Kadcyla®; Genentech; San Francisco) for the treatment of ErbB2-overexpressing metastatic breast cancer patients has validated the strong potential of these strategies. Even though the activity of ANPs and ADCs is dependent on lysosomal traffic, the roles of the endocytic route traversed by the targeted receptor and of cancer cell-specific alterations in receptor dynamics on the efficiency of drug delivery have not been considered in these new targeted therapies. For example, constitutive association with the molecular chaperone HSP90 is thought to either retard ErbB2 endocytosis or to promote its recycling, traits undesirable for targeted therapy with ANPs and ADCs. HSP90 inhibitors are known to promote ErbB2 ubiquitination, targeting to lysosome and degradation. We therefore hypothesized that ErbB2-targeted drug delivery using Trastuzumab-conjugated nanoparticles could be significantly improved by HSP90 inhibitor-promoted lysosomal traffic of ErbB2. Studies reported here validate this hypothesis and demonstrate, both in vitro and in vivo, that HSP90 inhibition facilitates the intracellular delivery of Trastuzumab-conjugated ANPs carrying a model chemotherapeutic agent, Doxorubicin, specifically into ErbB2-overexpressing breast cancer cells, resulting in improved antitumor activity. These novel findings highlight the need to consider oncogene-specific alterations in receptor traffic in the design of targeted drug delivery strategies. We suggest that combination of agents that enhance

  7. Marked enhancement of lysosomal targeting and efficacy of ErbB2-targeted drug delivery by HSP90 inhibition.

    PubMed

    Raja, Srikumar M; Desale, Swapnil S; Mohapatra, Bhopal; Luan, Haitao; Soni, Kruti; Zhang, Jinjin; Storck, Matthew A; Feng, Dan; Bielecki, Timothy A; Band, Vimla; Cohen, Samuel M; Bronich, Tatiana K; Band, Hamid

    2016-03-01

    Targeted delivery of anticancer drugs to tumor cells using monoclonal antibodies against oncogenic cell surface receptors is an emerging therapeutic strategy. These strategies include drugs directly conjugated to monoclonal antibodies through chemical linkers (Antibody-Drug Conjugates, ADCs) or those encapsulated within nanoparticles that in turn are conjugated to targeting antibodies (Antibody-Nanoparticle Conjugates, ANPs). The recent FDA approval of the ADC Trastuzumab-TDM1 (Kadcyla; Genentech; San Francisco) for the treatment of ErbB2-overexpressing metastatic breast cancer patients has validated the strong potential of these strategies. Even though the activity of ANPs and ADCs is dependent on lysosomal traffic, the roles of the endocytic route traversed by the targeted receptor and of cancer cell-specific alterations in receptor dynamics on the efficiency of drug delivery have not been considered in these new targeted therapies. For example, constitutive association with the molecular chaperone HSP90 is thought to either retard ErbB2 endocytosis or to promote its recycling, traits undesirable for targeted therapy with ANPs and ADCs. HSP90 inhibitors are known to promote ErbB2 ubiquitination, targeting to lysosome and degradation. We therefore hypothesized that ErbB2-targeted drug delivery using Trastuzumab-conjugated nanoparticles could be significantly improved by HSP90 inhibitor-promoted lysosomal traffic of ErbB2. Studies reported here validate this hypothesis and demonstrate, both in vitro and in vivo, that HSP90 inhibition facilitates the intracellular delivery of Trastuzumab-conjugated ANPs carrying a model chemotherapeutic agent, Doxorubicin, specifically into ErbB2-overexpressing breast cancer cells, resulting in improved antitumor activity. These novel findings highlight the need to consider oncogene-specific alterations in receptor traffic in the design of targeted drug delivery strategies. We suggest that combination of agents that enhance receptor

  8. Polar Markings

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA02155 Polar Markings

    These bright and dark markings occurred near the end of summer in the south polar region. The dark material is likely dust that has been freed of frost cover.

    Image information: VIS instrument. Latitude -76.3N, Longitude 84.9E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  9. The metabolic and performance effects of caffeine compared to coffee during endurance exercise.

    PubMed

    Hodgson, Adrian B; Randell, Rebecca K; Jeukendrup, Asker E

    2013-01-01

    There is consistent evidence supporting the ergogenic effects of caffeine for endurance based exercise. However, whether caffeine ingested through coffee has the same effects is still subject to debate. The primary aim of the study was to investigate the performance enhancing effects of caffeine and coffee using a time trial performance test, while also investigating the metabolic effects of caffeine and coffee. In a single-blind, crossover, randomised counter-balanced study design, eight trained male cyclists/triathletes (Mean ± SD: Age 41 ± 7 y, Height 1.80 ± 0.04 m, Weight 78.9 ± 4.1 kg, VO2 max 58 ± 3 ml • kg(-1) • min(-1)) completed 30 min of steady-state (SS) cycling at approximately 55% VO2max followed by a 45 min energy based target time trial (TT). One hour prior to exercise each athlete consumed drinks consisting of caffeine (5 mg CAF/kg BW), instant coffee (5 mg CAF/kg BW), instant decaffeinated coffee or placebo. The set workloads produced similar relative exercise intensities during the SS for all drinks, with no observed difference in carbohydrate or fat oxidation. Performance times during the TT were significantly faster (~5.0%) for both caffeine and coffee when compared to placebo and decaf (38.35 ± 1.53, 38.27 ± 1.80, 40.23 ± 1.98, 40.31 ± 1.22 min respectively, p<0.05). The significantly faster performance times were similar for both caffeine and coffee. Average power for caffeine and coffee during the TT was significantly greater when compared to placebo and decaf (294 ± 21 W, 291 ± 22 W, 277 ± 14 W, 276 ± 23 W respectively, p<0.05). No significant differences were observed between placebo and decaf during the TT. The present study illustrates that both caffeine (5 mg/kg/BW) and coffee (5 mg/kg/BW) consumed 1 h prior to exercise can improve endurance exercise performance. PMID:23573201

  10. Neurobehavioral hazard identification and characterization for caffeine.

    PubMed

    Turnbull, Duncan; Rodricks, Joseph V; Mariano, Gregory F

    2016-02-01

    This report evaluates the scientific literature on caffeine with respect to potential central nervous system (CNS) effects, specifically effects on sleep, anxiety, and aggression/risk-taking. Caffeine has been the subject of more scientific safety studies than any other food ingredient. It is important, therefore, to evaluate new studies in the context of this large existing body of knowledge. The safety of caffeine can best be described in a narrative form, and is not usefully expressed in terms of a "bright line" numerical value like an "acceptable daily intake" (ADI). Caffeine intake has been associated with a range of reversible physiological effects, in a few studies at levels of less than 100 mg in sensitive individuals. It is also clear that many people can tolerate much greater levels - perhaps up to 600-800 mg/day or more - without experiencing such effects. The reasons for this type of variability in response are described in this report. Based on all the available evidence, there is no reason to believe that experiencing such effects from caffeine intake has any significant or lasting effect on health. The point at which caffeine intake may cause harm to the CNS is not readily identifiable, in part because data on the effects of daily intakes greater than 600 mg is limited. Effects of caffeine on risk-taking and aggressive behavior in young people have received considerable publicity, yet are the most difficult to study because of ethical concerns and limitations in the ability to design appropriate studies. At present, the weight of available evidence does not support these concerns, yet this should not preclude ongoing careful monitoring of the scientific literature. PMID:26702789

  11. [Time course of inhibition of caffeine elimination in response to the oral depot contraceptive agent Deposiston. Hormonal contraceptives and caffeine elimination].

    PubMed

    Meyer, F P; Canzler, E; Giers, H; Walther, H

    1991-01-01

    In the course of six months, the influence of the oral depot contraceptive, Deposiston (3 mg ethinylestradiol sulphonate and 10 mg norethisterone acetate per menstrual cycle) on the pharmacokinetics of caffeine as a model substance was studied in seven women in intraindividual comparison. The first examination began prior to administration of Deposition. The women were subjected to little challenge as saliva was used as the measuring compartment. Deposiston was found markedly delay the elimination half-life life of caffeine (p less than 0.05): t1/2 prior to therapy 4.9 +/- 2.6 h and, after as little as 2 mg ethinylestradiol sulphonate 8.0 +/- 3.5 h. In contrast to the effect observed for preparations containing less estrogen, these longer half-lives persisted throughout the trial. As expected, the AUC values were slightly elevated during this period, whereas clearance values were reduced. PMID:2058339

  12. Couples' Pre-Pregnancy Caffeine Consumption Linked to Miscarriage Risk

    MedlinePlus

    ... Thursday, March 24, 2016 Couples’ pre-pregnancy caffeine consumption linked to miscarriage risk NIH study finds daily ... such lifestyle factors as cigarette use, caffeinated beverage consumption and multivitamin use among 344 couples with a ...

  13. Caffeine Intake -- Even Dad's -- Linked to Miscarriage, Study Says

    MedlinePlus

    ... new in this study is that men's caffeine consumption also appears to play a role, said Janis ... time to get your body ready -- reduce your consumption of caffeine, get to a healthy weight, don' ...

  14. Caffeine's Jolt Can Sometimes Be Short-Lived

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_159413.html Caffeine's Jolt Can Sometimes Be Short-Lived Stimulant effect ... 17, 2016 THURSDAY, June 16, 2016 (HealthDay News) -- Caffeine no longer improves alertness or mental performance after ...

  15. Smoking and caffeine and alcohol intake during pregnancy in a northern population: effect on fetal growth.

    PubMed Central

    Godel, J C; Pabst, H F; Hodges, P E; Johnson, K E; Froese, G J; Joffres, M R

    1992-01-01

    OBJECTIVES: To assess the prevalence of smoking and of caffeine and alcohol intake during pregnancy in a northern population and to determine the relation of these factors to birth weight, length and head circumference. DESIGN: Questionnaire survey and collection of maternal and newborn measurements. SETTING: Ten communities in the Inuvik Zone, NWT. PATIENTS: A total of 162 women (56 Inuit, 38 Indian, 37 white and 31 mixed race) who presented for prenatal care in their community and gave birth in Inuvik between September 1987 and January 1990 and their newborns. RESULTS: In all, 64% (101/159) of the women smoked, 57% (88/154) ingested more than 300 mg of caffeine daily, and 34% (50/145) drank alcohol during their pregnancy. Smoking, caffeine intake and binge drinking were most frequent among the Inuit and Indian mothers. Smoking was significantly associated with decreased birth weight (p less than 0.001) and length (p less than 0.05). Alcohol intake, especially binge drinking, was significantly associated with decreased head circumference (p less than 0.05). Caffeine was found not to be related to any of the outcome variables after smoking was controlled for through stepwise multiple regression. CONCLUSIONS: The marked prevalence of smoking and alcohol intake during pregnancy and their effects on the newborn are public health concerns in the Northwest Territories and warrant intensive countermeasures. PMID:1623464

  16. Caffeine use among active duty US Army soldiers.

    PubMed

    Lieberman, Harris R; Stavinoha, Trisha; McGraw, Susan; White, Alan; Hadden, Louise; Marriott, Bernadette P

    2012-06-01

    Eighty-percent of the US adult population regularly consumes caffeine, but limited information is available on the extent and patterns of use. Caffeine use is a public health issue and its risks and benefits are regularly considered in scientific literature and the lay media. Recently, new caffeine-containing products have been introduced and are widely available on Army bases and are added to rations to maintain cognitive performance. This study surveyed caffeine consumption and demographic characteristics in 990 US Army soldiers. Data were weighted by age, sex, rank, and Special Forces status. Total caffeine intake and intake from specific products were estimated. Logistic regression was used to examine relationships between caffeine use and soldier demographic and lifestyle characteristics. Eighty-two percent of soldiers consumed caffeine at least once a week. Mean daily caffeine consumption was 285 mg/day (347 mg/day among regular caffeine consumers). Male soldiers consumed, on average, 303 mg/day and females 163 mg/day (regular consumers: 365 mg/day for male soldiers, 216 mg/day for female soldiers). Coffee was the main source of caffeine intake. Among young males, energy drinks were the largest source of caffeine intake, but their intake was not greater than older males. Regression analysis indicated an association of higher caffeine intake with male sex, white race, and tobacco use (P<0.01). Most soldiers consume caffeine in levels accepted as safe, but some consume greater quantities than recommended, although definitive information on safe upper limits of caffeine intake is not available. Labels of caffeine-containing products should provide caffeine content so individuals can make informed decisions. PMID:22709816

  17. Caffeine Taste Signaling in Drosophila Larvae

    PubMed Central

    Apostolopoulou, Anthi A.; Köhn, Saskia; Stehle, Bernhard; Lutz, Michael; Wüst, Alexander; Mazija, Lorena; Rist, Anna; Galizia, C. Giovanni; Lüdke, Alja; Thum, Andreas S.

    2016-01-01

    The Drosophila larva has a simple peripheral nervous system with a comparably small number of sensory neurons located externally at the head or internally along the pharynx to assess its chemical environment. It is assumed that larval taste coding occurs mainly via external organs (the dorsal, terminal, and ventral organ). However, the contribution of the internal pharyngeal sensory organs has not been explored. Here we find that larvae require a single pharyngeal gustatory receptor neuron pair called D1, which is located in the dorsal pharyngeal sensilla, in order to avoid caffeine and to associate an odor with caffeine punishment. In contrast, caffeine-driven reduction in feeding in non-choice situations does not require D1. Hence, this work provides data on taste coding via different receptor neurons, depending on the behavioral context. Furthermore, we show that the larval pharyngeal system is involved in bitter tasting. Using ectopic expressions, we show that the caffeine receptor in neuron D1 requires the function of at least four receptor genes: the putative co-receptors Gr33a, Gr66a, the putative caffeine-specific receptor Gr93a, and yet unknown additional molecular component(s). This suggests that larval taste perception is more complex than previously assumed already at the sensory level. Taste information from different sensory organs located outside at the head or inside along the pharynx of the larva is assembled to trigger taste guided behaviors. PMID:27555807

  18. Caffeine Taste Signaling in Drosophila Larvae.

    PubMed

    Apostolopoulou, Anthi A; Köhn, Saskia; Stehle, Bernhard; Lutz, Michael; Wüst, Alexander; Mazija, Lorena; Rist, Anna; Galizia, C Giovanni; Lüdke, Alja; Thum, Andreas S

    2016-01-01

    The Drosophila larva has a simple peripheral nervous system with a comparably small number of sensory neurons located externally at the head or internally along the pharynx to assess its chemical environment. It is assumed that larval taste coding occurs mainly via external organs (the dorsal, terminal, and ventral organ). However, the contribution of the internal pharyngeal sensory organs has not been explored. Here we find that larvae require a single pharyngeal gustatory receptor neuron pair called D1, which is located in the dorsal pharyngeal sensilla, in order to avoid caffeine and to associate an odor with caffeine punishment. In contrast, caffeine-driven reduction in feeding in non-choice situations does not require D1. Hence, this work provides data on taste coding via different receptor neurons, depending on the behavioral context. Furthermore, we show that the larval pharyngeal system is involved in bitter tasting. Using ectopic expressions, we show that the caffeine receptor in neuron D1 requires the function of at least four receptor genes: the putative co-receptors Gr33a, Gr66a, the putative caffeine-specific receptor Gr93a, and yet unknown additional molecular component(s). This suggests that larval taste perception is more complex than previously assumed already at the sensory level. Taste information from different sensory organs located outside at the head or inside along the pharynx of the larva is assembled to trigger taste guided behaviors. PMID:27555807

  19. Caffeine Consumption Patterns and Beliefs of College Freshmen

    ERIC Educational Resources Information Center

    McIlvain, Gary E.; Noland, Melody P.; Bickel, Robert

    2011-01-01

    Background: Caffeine consumption by young people has increased dramatically over the last decade through increased coffee consumption and "energy drinks." In higher amounts, caffeine causes many adverse effects that are cause for concern. Purpose: Purposes of this study were to determine: (1) the amount of caffeine consumed by a sample of college…

  20. Caffeine Use Disorder: A Comprehensive Review and Research Agenda

    PubMed Central

    Meredith, Steven E.; Juliano, Laura M.; Hughes, John R.

    2013-01-01

    Caffeine is the most commonly used drug in the world. Although consumption of low to moderate doses of caffeine is generally safe, an increasing number of clinical studies are showing that some caffeine users become dependent on the drug and are unable to reduce consumption despite knowledge of recurrent health problems associated with continued use. Thus, the World Health Organization and some health care professionals recognize caffeine dependence as a clinical disorder. In this comprehensive literature review, we summarize published research on the biological evidence for caffeine dependence; we provide a systematic review of the prevalence of caffeine dependence and rates of endorsement of clinically meaningful indicators of distress and functional impairment among habitual caffeine users; we discuss the diagnostic criteria for Caffeine Use Disorder—a condition for further study included in the Diagnostic and Statistical Manual of Mental Disorders (5th ed.); and we outline a research agenda to help guide future clinical, epidemiological, and genetic investigations of caffeine dependence. Numerous controlled laboratory investigations reviewed in this article show that caffeine produces behavioral and physiological effects similar to other drugs of dependence. Moreover, several recent clinical studies indicate that caffeine dependence is a clinically meaningful disorder that affects a nontrivial proportion of caffeine users. Nevertheless, more research is needed to determine the reliability, validity, and prevalence of this clinically important health problem. PMID:24761279

  1. Beverage caffeine intakes in the U.S.

    PubMed

    Mitchell, Diane C; Knight, Carol A; Hockenberry, Jon; Teplansky, Robyn; Hartman, Terryl J

    2014-01-01

    Caffeine is one of the most researched food components, with the vast majority of dietary contributions coming from beverage consumption; however, there is little population-level data on caffeine intakes in the U.S. This study estimated the caffeine intakes of the U.S. population using a comprehensive beverage survey, the Kantar Worldpanel Beverage Consumption Panel. A nationally representative sample of 37,602 consumers (aged ≥ 2 years) of caffeinated beverages completed 7-day diaries which facilitated the development of a detailed database of caffeine values to assess intakes. Results showed that 85% of the U.S. population consumes at least one caffeinated beverage per day. The mean (±SE) daily caffeine intake from all beverages was 165±1 mg for all ages combined. Caffeine intake was highest in consumers aged 50-64 years (226±2 mg/day). The 90th percentile intake was 380 mg/day for all ages combined. Coffee was the primary contributor to caffeine intakes in all age groups. Carbonated soft drinks and tea provided a greater percentage of caffeine in the younger (<18 years) age groups. The percentage of energy drink consumers across all age groups was low (≤10%). These data provide a current perspective on caffeinated beverage consumption patterns and caffeine intakes in the U.S. population. PMID:24189158

  2. Caffeine Use Disorder: A Comprehensive Review and Research Agenda.

    PubMed

    Meredith, Steven E; Juliano, Laura M; Hughes, John R; Griffiths, Roland R

    2013-09-01

    Caffeine is the most commonly used drug in the world. Although consumption of low to moderate doses of caffeine is generally safe, an increasing number of clinical studies are showing that some caffeine users become dependent on the drug and are unable to reduce consumption despite knowledge of recurrent health problems associated with continued use. Thus, the World Health Organization and some health care professionals recognize caffeine dependence as a clinical disorder. In this comprehensive literature review, we summarize published research on the biological evidence for caffeine dependence; we provide a systematic review of the prevalence of caffeine dependence and rates of endorsement of clinically meaningful indicators of distress and functional impairment among habitual caffeine users; we discuss the diagnostic criteria for Caffeine Use Disorder-a condition for further study included in the Diagnostic and Statistical Manual of Mental Disorders (5(th) ed.); and we outline a research agenda to help guide future clinical, epidemiological, and genetic investigations of caffeine dependence. Numerous controlled laboratory investigations reviewed in this article show that caffeine produces behavioral and physiological effects similar to other drugs of dependence. Moreover, several recent clinical studies indicate that caffeine dependence is a clinically meaningful disorder that affects a nontrivial proportion of caffeine users. Nevertheless, more research is needed to determine the reliability, validity, and prevalence of this clinically important health problem. PMID:24761279

  3. Caffeine-induced increase in voluntary activation and strength of the quadriceps muscle during isometric, concentric and eccentric contractions.

    PubMed

    Behrens, Martin; Mau-Moeller, Anett; Weippert, Matthias; Fuhrmann, Josefin; Wegner, Katharina; Skripitz, Ralf; Bader, Rainer; Bruhn, Sven

    2015-01-01

    This study investigated effects of caffeine ingestion (8 mg/kg) on maximum voluntary torque (MVT) and voluntary activation of the quadriceps during isometric, concentric and eccentric contractions. Fourteen subjects ingested caffeine and placebo in a randomized, controlled, counterbalanced, double-blind crossover design. Neuromuscular tests were performed before and 1 h after oral caffeine and placebo intake. MVTs were measured and the interpolated twitch technique was applied during isometric, concentric and eccentric contractions to assess voluntary activation. Furthermore, normalized root mean square of the EMG signal was calculated and evoked spinal reflex responses (H-reflex evoked at rest and during weak isometric voluntary contraction) as well as twitch torques were analyzed. Caffeine increased MVT by 26.4 N m (95%CI: 9.3-43.5 N m, P = 0.004), 22.5 N m (95%CI: 3.1-42.0 N m, P = 0.025) and 22.5 N m (95%CI: 2.2-42.7 N m, P = 0.032) for isometric, concentric and eccentric contractions. Strength enhancements were associated with increases in voluntary activation. Explosive voluntary strength and voluntary activation at the onset of contraction were significantly increased following caffeine ingestion. Changes in spinal reflex responses and at the muscle level were not observed. Data suggest that caffeine ingestion induced an acute increase in voluntary activation that was responsible for the increased strength regardless of the contraction mode. PMID:25969895

  4. Associations of ambulatory blood pressure with urinary caffeine and caffeine metabolite excretions.

    PubMed

    Guessous, Idris; Pruijm, Menno; Ponte, Belén; Ackermann, Daniel; Ehret, Georg; Ansermot, Nicolas; Vuistiner, Philippe; Staessen, Jan; Gu, Yumei; Paccaud, Fred; Mohaupt, Markus; Vogt, Bruno; Pechère-Bertschi, Antoinette; Pechère-Berstchi, Antoinette; Martin, Pierre-Yves; Burnier, Michel; Eap, Chin B; Bochud, Murielle

    2015-03-01

    Intake of caffeinated beverages might be associated with reduced cardiovascular mortality possibly via the lowering of blood pressure. We estimated the association of ambulatory blood pressure with urinary caffeine and caffeine metabolites in a population-based sample. Families were randomly selected from the general population of Swiss cities. Ambulatory blood pressure monitoring was conducted using validated devices. Urinary caffeine, paraxanthine, theophylline, and theobromine excretions were measured in 24 hours urine using ultrahigh performance liquid chromatography tandem mass spectrometry. We used mixed models to explore the associations of urinary excretions with blood pressure although adjusting for major confounders. The 836 participants (48.9% men) included in this analysis had mean age of 47.8 and mean 24-hour systolic and diastolic blood pressure of 120.1 and 78.0 mm Hg. For each doubling of caffeine excretion, 24-hour and night-time systolic blood pressure decreased by 0.642 and 1.107 mm Hg (both P values <0.040). Similar inverse associations were observed for paraxanthine and theophylline. Adjusted night-time systolic blood pressure in the first (lowest), second, third, and fourth (highest) quartile of paraxanthine urinary excretions were 110.3, 107.3, 107.3, and 105.1 mm Hg, respectively (P trend <0.05). No associations of urinary excretions with diastolic blood pressure were generally found, and theobromine excretion was not associated with blood pressure. Anti-hypertensive therapy, diabetes mellitus, and alcohol consumption modify the association of caffeine urinary excretion with systolic blood pressure. Ambulatory systolic blood pressure was inversely associated with urinary excretions of caffeine and other caffeine metabolites. Our results are compatible with a potential protective effect of caffeine on blood pressure. PMID:25489060

  5. The effect of caffeine on the reactions of the excited singlet state of pyrene in micellar sodium lauryl sulfate

    NASA Astrophysics Data System (ADS)

    Hashimoto, Shuichi; Thomas, J. Kerry

    1984-08-01

    The effect of caffeine on a few photo-induced reactions of pyrene in micellar sodium lauryl sulfate (NaLS) has been studied. In these systems caffeine complexes with the pyrene (K asso = 85 ± 10 M -1 and also with the other reactants, e.g. Cu 2+ or TI +. The efficiencies of reactions which involve contact, i.e. pyrene excimer formation, and quenching by TI + ions to give the triplet state of pyrene, are significantly reduced in the presence of caffeine, due to geometric inhibitions formed by the complexation processes. The kinetics of photo-induced electron transfer, e.g. between excited pyrene and Cu 2+, are not affected. However, the subsequent reactions of the products are modified and the yield of ionic products is markedly increased.

  6. Effect of caffeine on the expression of a major X-ray induced protein in human tumor cells

    SciTech Connect

    Hughes, E.N.; Boothman, D.A. )

    1991-03-01

    We have examined the effect of caffeine on the concomitant processes of the repair of potentially lethal damage (PLD) and the synthesis of X-ray-induced proteins in the human malignant melanoma cell line, Ul-Mel. Caffeine administered at a dose of 5mM after X radiation not only inhibited PLD repair but also markedly reduced the level of XIP269, a major X-ray-induced protein whose expression has been shown to correlate with the capacity to repair PLD. The expression of the vast majority of other cellular proteins, including seven other X-ray-induced proteins, remained unchanged following caffeine treatment. A possible role for XIP269 in cell cycle delay following DNA damage by X irradiation is discussed.

  7. Single and combined effects of beetroot juice and caffeine supplementation on cycling time trial performance.

    PubMed

    Lane, Stephen C; Hawley, John A; Desbrow, Ben; Jones, Andrew M; Blackwell, James R; Ross, Megan L; Zemski, Adam J; Burke, Louise M

    2014-09-01

    Both caffeine and beetroot juice have ergogenic effects on endurance cycling performance. We investigated whether there is an additive effect of these supplements on the performance of a cycling time trial (TT) simulating the 2012 London Olympic Games course. Twelve male and 12 female competitive cyclists each completed 4 experimental trials in a double-blind Latin square design. Trials were undertaken with a caffeinated gum (CAFF) (3 mg·kg(-1) body mass (BM), 40 min prior to the TT), concentrated beetroot juice supplementation (BJ) (8.4 mmol of nitrate (NO3(-)), 2 h prior to the TT), caffeine plus beetroot juice (CAFF+BJ), or a control (CONT). Subjects completed the TT (females: 29.35 km; males: 43.83 km) on a laboratory cycle ergometer under conditions of best practice nutrition: following a carbohydrate-rich pre-event meal, with the ingestion of a carbohydrate-electrolyte drink and regular oral carbohydrate contact during the TT. Compared with CONT, power output was significantly enhanced after CAFF+BJ and CAFF (3.0% and 3.9%, respectively, p < 0.01). There was no effect of BJ supplementation when used alone (-0.4%, p = 0.6 compared with CONT) or when combined with caffeine (-0.9%, p = 0.4 compared with CAFF). We conclude that caffeine (3 mg·kg(-1) BM) administered in the form of a caffeinated gum increased cycling TT performance lasting ∼50-60 min by ∼3%-4% in both males and females. Beetroot juice supplementation was not ergogenic under the conditions of this study. PMID:25154895

  8. Caffeine Inhibits Acetylcholinesterase, But Not Butyrylcholinesterase

    PubMed Central

    Pohanka, Miroslav; Dobes, Petr

    2013-01-01

    Caffeine is an alkaloid with a stimulant effect in the body. It can interfere in transmissions based on acetylcholine, epinephrine, norepinephrine, serotonin, dopamine and glutamate. Clinical studies indicate that it can be involved in the slowing of Alzheimer disease pathology and some other effects. The effects are not well understood. In the present work, we focused on the question whether caffeine can inhibit acetylcholinesterase (AChE) and/or, butyrylcholinesterase (BChE), the two enzymes participating in cholinergic neurotransmission. A standard Ellman test with human AChE and BChE was done for altering concentrations of caffeine. The test was supported by an in silico examination as well. Donepezil and tacrine were used as standards. In compliance with Dixon’s plot, caffeine was proved to be a non-competitive inhibitor of AChE and BChE. However, inhibition of BChE was quite weak, as the inhibition constant, Ki, was 13.9 ± 7.4 mol/L. Inhibition of AChE was more relevant, as Ki was found to be 175 ± 9 μmol/L. The predicted free energy of binding was −6.7 kcal/mol. The proposed binding orientation of caffeine can interact with Trp86, and it can be stabilize by Tyr337 in comparison to the smaller Ala328 in the case of human BChE; thus, it can explain the lower binding affinity of caffeine for BChE with reference to AChE. The biological relevance of the findings is discussed. PMID:23698772

  9. Effects of hyperoxia and caffeine on the expression of fragile site at Xq27.3

    SciTech Connect

    Rafi, S.K.; Surana, R.B.; Christopher, K.L.

    1996-02-02

    To enhance the cytogenetic expression of the fragile X chromosome, we studied the effects of hyperoxia and caffeine on the induction of fragile Xq27.3. A lymphoblastoid cell line (GM 06912) derived from a fragile X male proband was cultured in RPMI 1640 containing 16% dialyzed fetal calf serum. The cells were synchronously subjected to one of 3 different atmospheric oxygen tensions (21%, 21.3 kPa, hyperoxic) during the last 24 hours of the 72 hour culture, immediately after the addition of 2{prime}-deoxy-5-fluorouridine (FUdR) at 25 ng/ml. To study the enhancing effect of caffeine, with or without hyperoxia, a second set of cultures was additionally subjected to caffeine (2.5 mM) during the last 6 hours of the culture. When the fragility of hyperoxic cells (38.1 kPa dissolved oxygen) was compared to that of normoxic control cells (13.3 kPa dissolved oxygen), the difference was significant (P < 0.05). These data suggest that there is a mean increase in the fragile Xq27.3 expressivity as the dissolved oxygen tension increases. Additionally, we observed that caffeine, with or without hyperoxia, significantly (P <0.05) suppressed the expression of the fragile X site in this lymphoblastoid cell line. 34 refs., 2 tabs.

  10. Potentiation of morphine analgesia by caffeine.

    PubMed Central

    Misra, A. L.; Pontani, R. B.; Vadlamani, N. L.

    1985-01-01

    Significant potentiation of morphine (5 mg kg-1 s.c. or 1 mg kg-1 i.v.) analgesia (tail-withdrawal reflex at 55 degrees C) was observed in caffeine-treated (100 mg kg-1 i.p.) rats as compared to the control group and lower doses of caffeine (2mg kg-1 i.p.) did not show this effect. Potentiated analgesia was reversed by naloxone. Pharmacokinetic or dispositional factors appear to be involved in part in this potentiation. PMID:4005485