Criterion for initiating hemodialysis based on serum caffeine concentration in treating severe caffeine poisoning

2021 ◽  
Author(s):  
Tomohiro Yoshizawa ◽  
Yoshito Kamijo ◽  
Tomoki Hanazawa ◽  
Kiyotaka Usui
Keyword(s):  
Caffeine Concentration

scholarly journals Applicability of Cork as Novel Modifiers to Develop Electrochemical Sensor for Caffeine Determination

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 37
Author(s):  
Mayra K. S. Monteiro ◽  
Djalma R. Da Silva ◽  
Marco A. Quiroz ◽  
Vítor J. P. Vilar ◽  
Carlos A. Martínez-Huitle ◽  
...  
Keyword(s):  
Electrochemical Sensor ◽  
Linear Response ◽  
High Performance ◽  
Low Cost ◽  
Pharmaceutical Formulations ◽  
Caffeine Concentration ◽  
Real Samples ◽  
Wide Range ◽  
Potential Use

This study aims to investigate the applicability of a hybrid electrochemical sensor composed of cork and graphite (Gr) for detecting caffeine in aqueous solutions. Raw cork (RAC) and regranulated cork (RGC, obtained by thermal treatment of RAC with steam at 380 °C) were tested as modifiers. The results clearly showed that the cork-graphite sensors, GrRAC and GrRGC, exhibited a linear response over a wide range of caffeine concentration (5–1000 µM), with R2 of 0.99 and 0.98, respectively. The limits of detection (LOD), estimated at 2.9 and 6.1 µM for GrRAC and GrRGC, suggest greater sensitivity and reproducibility than the unmodified conventional graphite sensor. The low-cost cork-graphite sensors were successfully applied in the determination of caffeine in soft drinks and pharmaceutical formulations, presenting well-defined current signals when analyzing real samples. When comparing electrochemical determinations and high performance liquid chromatography measurements, no significant differences were observed (mean accuracy 3.0%), highlighting the potential use of these sensors to determine caffeine in different samples.

Does Caffeine Consumption Influence Postcompetition Sleep in Professional Rugby League Athletes? A Case Study

2021 ◽  
pp. 1-4
Author(s):  
Johnpaul Caia ◽  
Shona L. Halson ◽  
Patrick M. Holmberg ◽  
Vincent G. Kelly
Keyword(s):  
Sleep Duration ◽  
Pearson Correlation ◽  
Rugby League ◽  
Caffeine Intake ◽  
Caffeine Consumption ◽  
Caffeine Concentration ◽  
Previous Night ◽  
Activity Monitors ◽  
The Relationship

Purpose: To examine the sleep of rugby league athletes the night before and following an evening match and to investigate the association between caffeine intake and sleep on the night of competition. Methods: On the night prior to, night of, and night after a professional rugby league match, 15 athletes had their sleep monitored using wrist activity monitors. Additionally, saliva samples were collected 60 minutes before and 30 minutes after the competition to assess salivary caffeine concentration. Differences in sleep across the 3 nights were examined using linear mixed models, and changes were assessed using effect size (ES). Pearson correlation (r) assessed the relationship between salivary caffeine levels and sleep indices. Results: On the night of competition, athletes went to bed later than the night before (P = .00002, ES = 1.84) and night after (P = .0003, ES = 1.49) competition. Consequently, their sleep duration was reduced on the night of competition compared with the previous night (P < .0000003, ES = 2.36) and night after competition (P = .001, ES = 1.53). Postcompetition salivary caffeine concentration was substantially elevated in athletes when compared with precompetition measures (P < .00000001, ES = 4.44), and moderate, nonsignificant correlations were observed between changes in salivary caffeine concentration and delayed bedtime (r = .48, P = .07), increased sleep latency (r = .45, P = .09), decreased sleep duration (r = −.30, P = .28), and reduced sleep efficiency (r = −.34, P = .22). Conclusions: These results demonstrate that evening competition results in sleep disturbance in rugby league athletes, and caffeine supplementation prior to and during competition leads to substantial increases in postcompetition salivary caffeine concentration.

scholarly journals Caffeine release and absorption from caffeinated gums

2019 ◽  
Vol 10 (4) ◽  
pp. 1792-1796 ◽  
Author(s):  
Cecile Morris ◽  
Sophie M. Viriot ◽  
Qurat U. A. Farooq Mirza ◽  
Gordon A. Morris ◽  
Anthony Lynn
Keyword(s):  
Gastrointestinal Tract ◽  
Oral Mucosa ◽  
Caffeine Concentration

Caffeine release increased with chewing time (2 min < 5 min < 10 min). Two plasma caffeine concentration peaks were observed suggesting that caffeine absorption occurs both through the oral mucosa and gastrointestinal tract.

Metabolic, catecholamine, and exercise performance responses to various doses of caffeine

1995 ◽  
Vol 78 (3) ◽  
pp. 867-874 ◽  
Author(s):  
T. E. Graham ◽  
L. L. Spriet
Keyword(s):  
Ergogenic Effect ◽  
Endurance Athletes ◽  
Traditional Theory ◽  
Endurance Capacity ◽  
O2 Consumption ◽  
Caffeine Concentration ◽  
Blood Samples ◽  
Caffeine Metabolism ◽  
The Impact ◽  
Higher Doses

This study examined the exercise responses of well-trained endurance athletes to various doses of caffeine to evaluate the impact of the drug on exercise metabolism and endurance capacity. Subjects (n = 8) withdrew from all dietary sources of caffeine for 48 h before each of four tests. One hour before exercise they ingested capsules of placebo or caffeine (3, 6, or 9 mg/kg), rested quietly, and then ran at 85% of maximal O2 consumption to voluntary exhaustion. Blood samples for methylxanthine, catecholamine, glucose, lactate, free fatty acid, and glycerol analyses were taken every 15 min. Plasma caffeine concentration increased with each dose (P < 0.05). Its major metabolite, paraxanthine, did not increase between the 6 and 9 mg/kg doses, suggesting that hepatic caffeine metabolism was saturated. Endurance was enhanced with both 3 and 6 mg/kg of caffeine (increases of 22 +/- 9 and 22 +/- 7%, respectively; both P < 0.05) over the placebo time of 49.4 +/- 4.2 min, whereas there was no significant effect with 9 mg/kg of caffeine. In contrast, plasma epinephrine was not increased with 3 mg/kg of caffeine but was greater with the higher doses (P < 0.05). Similarly only the highest dose of caffeine resulted in increases in glycerol and free fatty acids (P < 0.05). Thus the highest dose had the greatest effect on epinephrine and blood-borne metabolites yet had the least effect on performance. The lowest dose had little or no effect on epinephrine and metabolites but did have an ergogenic effect. These results are not compatible with the traditional theory that caffeine mediates its ergogenic effect via enhanced catecholamines.

scholarly journals Electrochemical Determination of Caffeine Content in Ethiopian Coffee Samples Using Lignin Modified Glassy Carbon Electrode

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Meareg Amare ◽  
Senait Aklog
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Electrochemical Determination ◽  
Carbon Electrode ◽  
Complex Matrix ◽  
Method Detection Limit ◽  
Modified Glassy Carbon Electrode ◽  
Caffeine Concentration ◽  
Caffeine Content

Lignin film was deposited at the surface of glassy carbon electrode potentiostatically. In contrast to the unmodified glassy carbon electrode, an oxidative peak with an improved current and overpotential for caffeine at modified electrode showed catalytic activity of the modifier towards oxidation of caffeine. Linear dependence of peak current on caffeine concentration in the range 6×10-6 to 100×10-6 mol L−1 with determination coefficient and method detection limit (LoD = 3 s/slope) of 0.99925 and 8.37×10-7 mol L−1, respectively, supplemented by recovery results of 93.79–102.17% validated the developed method. An attempt was made to determine the caffeine content of aqueous coffee extracts of Ethiopian coffees grown in four coffee cultivating localities (Wonbera, Wolega, Finoteselam, and Zegie) and hence to evaluate the correlation between users preference and caffeine content. In agreement with reported works, caffeine contents (w/w%) of 0.164 in Wonbera coffee; 0.134 in Wolega coffee; 0.097 in Finoteselam coffee; and 0.089 in Zegie coffee were detected confirming the applicability of the developed method for determination of caffeine in a complex matrix environment. The result indicated that users’ highest preference for Wonbera and least preference for Zegie cultivated coffees are in agreement with the caffeine content.

scholarly journals Estimation of Caffeine Concentration in Decaffeinated Coffee and Tea Available in Pakistan

2018 ◽  
Vol 12 (1) ◽  
pp. 229-247
Author(s):  
Muhammad Sadiq ◽  
Effat Zohra ◽  
Muhammad Jamil ◽  
Muhammad Wasim ◽  
Humayun Riaz ◽  
...  
Keyword(s):  
Caffeine Concentration ◽  
Decaffeinated Coffee
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