Efficacy of caffeine and modafinil in counteracting sleep deprivation in the marmoset monkey

Interactions of skin thickness and physicochemical properties of test compounds in percutaneous penetration studies

Objectives: To determine the effect of skin thickness on the percutaneous penetration and distribution of test compounds with varying physicochemical properties using in vitro systems. Studies were carried out in accordance with OECD guidelines on skin absorption tests. Methods: Percutaneous penetration of caffeine (log P -0.01), testosterone ...

Effect of folate-binding protein on intestinal transport of folic acid and 5-methyltetrahydrofolate across Caco-2 cells

Background: Milk products are a potential matrix for fortification with synthetic folic acid or natural 5-methyltetrahydrofolate (5-CH 3-H4folate) to enhance the daily folate intake. In milk, folate occurs bound to folatebinding proteins (FBP). Our previous studies with an in vitro gastrointestinal model showed that 70% of the initial FBP...

Effects of coffee consumption on fasting blood glucose and insulin concentrations: Randomized controlled trials in healthy volunteers

In vitro predictions of skin absorption of caffeine, testosterone, and benzoic acid: A multi-centre comparison study

To obtain better insight into the robustness of in vitro percutaneous absorption methodology, the intra- and inter-laboratory variation in this type of study was investigated in 10 European laboratories. To this purpose, the in vitro absorption of three compounds through human skin (9 laboratories) and rat skin (1 laboratory) was determined. The...

Generic solid phase extraction-liquid chromatography-tandem mass spectrometry method for fast determination of drugs in biological fluids

A generic method was developed for the fast determination of a wide range of drugs in serum or plasma. The methodology comprises generic solid-phase extraction, on-line coupled to gradient HPLC with tandem mass spectrometric detection (SPE-LC-MS/MS). The individual components of the SPE-LC-MS/MS system were optimized in an integrated approach to...

Contribution of caffeine to the homocysteine-raising effect of coffee: A randomized controlled trial in humans

Background: A high plasma total homocysteine concentration is associated with increased risk of cardiovascular disease. Consumption of unfiltered or filtered coffee raises total homocysteine concentrations in healthy volunteers. The responsible compound, however, is unknown. Objective: The objective was to determine whether caffeine explains the...

Cyclopiazonic acid inhibits mutagenic action of aflatoxin B1

Cyclopiazonic acid and aflatoxin B1 are mycotoxins which can both be produced by the same moulds. Men can be exposed to these mycotoxins directly via ingestion of plant-derived food, as well as, indirectly via consumption of animal products. Although it is well known that aflatoxin B1 is mutagenic, contradictory results exist on the mutagenicity...

Beat-to-beat measurement of cardiovascular effects of a single subcutaneous dose of terbutaline in healthy subjects

Objective: To evaluate the cardiovascular effects over time of a single subcutaneous (SC) dose of terbutaline 0.75mg in young healthy volunteers using continuous, beat-to-beat monitoring of cardiovascular effects. Design and methods: Nine healthy young volunteers were administered a SC dose of terbutaline sulphate 0.75mg. Cardiovascular effects...

The effect of different dosages of caffeine on endurance performance time

The effect of different dosages of caffeine (0 - 5 - 9 - 13 mg · kg body weight-1) on endurance performance was examined. Nine well-trained cyclists participated in this study (VO2max 65.1 + 2.6 ml · kg-1 · min-1). Caffeine capsules were administered in random order and double-blind. One hour after capsule ingestion, subjects cycled until...