Caffeine

The OECD guideline for studies on percutaneous penetration to be used in hazard and risk evaluations prescribes experimental conditions with optimal barrier integrity of the skin, which in many occupational settings probably is not true. Thus, workers may have compromised skin due to chemical or mechanical damage, due to different medical conditions (eczema, dermatitis, skin irritation) or related to occupational scenarios involving prolonged wet work. The present study used the OECD guideline procedures to study the in vitro percutaneous penetration through human skin of a number of model substances (glyphosat, caffeine, benzoic acid, malathion) covering a range of solubilities. Further, we studied the extent to which a slightly damaged skin would change the rate, the amount absorbed during dermal exposure and the distribution of chemical deposition between epidermis and dermis. The present study demonstrates that a limited damage to the skin significantly increases the permeability coefficient (K p) as well as total percutaneous penetration of chemicals, and most significantly for those compounds that due to their physicochemical characteristics (the most hydrophilic as well as the most lipophilic) have low penetration rates through intact skin. The present experiment not only confirms the proportionality between lipophilicity and potential for percutaneous penetration, but also illustrates that at a certain degree of lipophilicity of a model compound, the different skin compartments become more attractive for temporary deposition of model compounds. Moreover, a clear change from epidermal deposition towards a dominating dermis deposition of chemicals temporarily deposited within the skin is seen following damage to the skin barrier. Thus, the distribution of chemicals within the skin compartments is affected by the physicochemical characteristics of the chemicals as well as by the integrity of the skin. This observation may have implications when evaluating the possibility of removing chemicals from the skin through different cleansing procedures following unintended dermal exposures.

Carbohydrate and caffeine are known to independently improve certain aspects of athletic performance. However, less is understood about physiological and performance outcomes when these compounds are coingested in a rehydration and carbohydrate-replacement strategy. The aim of this study was to examine the influence of adding a moderate dose of caffeine to a carbohydrate solution during prolonged soccer activity. Fifteen male soccer players performed two 90-min intermittent shuttle-running trials. They ingested a carbohydrate-electrolyte solution (CON) providing a total of 1.8 g/kg body mass (BM) of carbohydrate or a similar solution with added caffeine (CAF; 3.7 mg/kg BM). Solutions were ingested 1 hr before exercise and every 15 min during the protocol. Soccer passing skill and countermovement-jump height (CMJ) were quantified before exercise and regularly during exercise. Sprinting performance, heart rate, blood lactate concentration (La) and the subjective experiences of partici...

Les apnées du prématuré constituent encore actuellement un problème clinique majeur, imposant des choix thérapeutiques parfois difficiles. Des apnées plus ou moins longues surviennent chez presque tous les grands prématurés, témoignant d’une instabilité de la régulation respiratoire en rapport avec l’immaturité. Au rôle causal de celle-ci peut toutefois s’ajouter celui de nombreuses pathologies néonatales, qui peuvent aussi contribuer à la survenue d’apnées et doivent être recherchées et traitées. Les apnées du prématuré de courte durée (moins de dix secondes, sans hypoxémie ou bradycardie associée) peuvent être considérées comme sans risque pour l’enfant. Les apnées plus longues entraînent une hypoxémie et un ralentissement de la fréquence cardiaque et des perturbations de l’hémodynamique et de l’oxygénation cérébrales, susceptibles d’entraîner des effets délétères pour le développement à long terme. L’évaluation de leur degré de gravité immédiate et de leurs risques à long terme demeure imprécise. Les décisions thérapeutiques ne peuvent s’appuyer que sur assez peu de données scientifiques. Le citrate de caféine est un traitement efficace des apnées du prématuré, largement utilisé depuis des décennies. Mais c’est seulement très récemment qu’une évaluation rigoureuse de ses bénéfices et de ses inconvénients a été menée. Elle a mis en évidence la faible toxicité du citrate de caféine, et des bénéfices inattendus chez les enfants traités : diminution de fréquence des dysplasies bronchopulmonaires, de la persistance du canal artériel, et, à 18 mois, diminution du taux d’infirmité motrice cérébrale. La pression expiratoire positive par voie nasale, traitement également efficace des apnées, peut être utilisée en cas d’échec ou d’insuffisance du traitement par caféine et en association avec lui.Prematurity apnea remains a major clinical problem that requires treatment choices which are sometimes difficult. Prematurity apnea occurs in most infants of gestational age at birth less than 33 weeks. It is a developmental disorder which usually reflects a “physiological” immaturity of respiratory control. However, neonatal diseases may be associated and play an additive role, resulting in an increased incidence of apnea. Careful screening should therefore be performed in order to make sure that no other factor than immaturity is involved in the occurrence of apnea. Short apnea (less than 10 s, without hypoxemia and bradycardia), due to immaturity, are not clinically relevant. More prolonged apnea, that last for more than 15 or 20 s, and / or apnea associated with bradycardia or oxygen desaturation, results in short-term disturbances of cerebral haemodynamics and oxygenation, which may negatively impact on neurodevelopmental outcome. Evaluating the immediate severity of apnea and the risks that apnea may affect long-term outcome remains a challenge. The choice of treatments is based on a few evidences. Caffeine citrate, which reduces the incidence of apnea, has been used for decades. However, a thorough evaluation of risks and benefits of this medication has been performed only recently. Caffeine citrate was found to be safe and resulted in unexpected benefits. In treated infants, compared with controls, indeed, a decreased incidence of the following complications was recorded: bronchopulmonary dysplasia at 36 weeks of conceptional age, patent ductus arteriosus, cerebral palsy at 18 months of age. Nasal CPAP can be used in association with caffeine citrate, when the latter is not effective enough.

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.

Left ventricular hypertrophy (LVH) is a compensatory mechanism in response to an increased work load on the heart. This study investigated the impact of chronic isoprenaline and caffeine (I/C model) administration on cardiac geometry, systemic hemodynamic and physiological data in rats as LVH develops. LVH was induced by administering isoprenaline (5 mg/kg s.c. every 72 h) and caffeine (62 mg/L) in drinking water for 14 days to Wistar Kyoto (WKY) rats. Mean arterial pressure (MAP), systolic blood pressure (SBP), heart weight, LV weight, LV chamber diameter and thickness of myocardium were observed as LVH indicators. MAP was significantly higher (142 ± 13 vs. 119 ± 2 mmHg, respectively) while heart rate (HR) in LVH was lower (314 ± 9 vs. 264 ± 18 BPM) compared to control WKY. Heart weight, LV weight and kidney weight were 31%, 38% and 7%, respectively, greater in the LVH group as compared to the control WKY (all p < 0.05).The myocardium thickness was 101% greater while LV chamber ...

The main aim of this study was to evaluate the comparative and additive effects of caffeine and albuterol (short-acting beta (2)-agonist) on the severity of EIB. Ten asthmatic subjects with EIB (exercise-induced bronchoconstriction) participated in a randomized, double-blind, double-dummy crossover study. One hour before an exercise challenge, each subject was given 0, 3, 6, or 9 mg/kg of caffeine or placebo mixed in a flavored sugar drink. Fifteen minutes before the exercise bout, an inhaler containing either albuterol (180 microg) or placebo was administered to each subject. Pulmonary function tests were conducted pre- and post-exercise. Caffeine at a dose of 6 and 9 mg/kg significantly reduced (p<0.05) the mean maximum % fall in post-exercise FEV (1) to -9.0+/-9.2% and -6.8+/-6.5% respectively compared to the double-placebo (-14.3+/-11.1%) and baseline (-18.4+/-7.2%). There was no significant difference (p>0.05) in the post-exercise % fall in FEV (1) between albuterol ( PLU...

Nutrition plays a role in the etiology of osteoporosis. Two of the most important nutrients for bone health are calcium and vitamin D. Plasma 25-hydroxyvitamin D [25-(OH) D] is the most sensitive clinical index of vitamin D status and has been found to be positively related to ...

Alcohol clamping is a technique that maintains a constant breath alcohol Concentration (BrAC) for prolonged intervals, thereby reducing experimental variance in the timc course of organ exposure to alcohol, when compared with oral alcohol administration paradigms. ...

Objectives: This study investigated the relationships between a mindfulness‐based stress reduction meditation program for early stage breast and prostate cancer patients and quality of life, mood states, stress symptoms, lymphocyte counts, and cytokine production. Methods: Forty‐nine patients with breast cancer and 10 with prostate cancer participated in an 8‐week MBSR program that incorporated relaxation, meditation, gentle yoga, and daily home practice. Demographic and health behavior variables, quality of life (EORTC QLQ C‐30), mood (POMS), stress (SOSI), and counts of NK, NKT, B, T total, T helper, and T cytotoxic cells, as well as NK and T cell production of TNF, IFN‐&ggr;, IL‐4, and IL‐10 were assessed pre‐ and postintervention. Results: Fifty‐nine and 42 patients were assessed pre‐ and postintervention, respectively. Significant improvements were seen in overall quality of life, symptoms of stress, and sleep quality. Although there were no significant changes in the overall n...

It has previously been shown that it is possible to obtain metaphase chromosomes from single blastomeres converted into metaphase in the cytoplasm of a mouse zygote. This method is highly labour intensive and cannot be performed outside the preimplantation genetic diagnosis (PGD) laboratory, so to overcome these limitations, a method was developed for obtaining metaphase spreads from single biopsied blastomeres using different chemicals. The substances tested were calyculin A, caffeine, paclitaxel and colcemid in a total of 496 disaggregated and 234 biopsied blastomeres from day 3 embryos. It was demonstrated that the optimal method involved a combined use of ‘selective biopsy’ (selection of the biopsied blastomere according to morphological criteria) and exposure to caffeine. This resulted in shortening the mean incubation time of biopsied blastomeres, with a metaphase formation rate of 80%. The method is simple for obtaining metaphases from single blastomeres, and may be implemented in clinical practice of PGD for structural rearrangements.