Hemocyanins are allosterically regulated oxygen carriers freely dissolved in the blood of many crustaceans. The natural modulator urate accumulates under hypoxic conditions in the hemolymph of Homarus vulgaris, and increases the oxygen affinity of the respiratory pigment. Other non-physiological effectors such as caffeine, dimethylxanthines and methylxanthines are also known to modulate the oxy...

Methylxanthines, such as theophylline, have been used to treat cardiorespiratory disorders, whereas caffeine is the most widely consumed psychoactive agent in various soft drinks. Because of the worldwide use of these drugs and the recently synthesized xanthine derivatives, an intensive research on the cardiac actions of these substances is under progress. This review focuses on the molecular m...

The investigation of the link between diet and cancer in man has resulted in the identification of a variety of carcinogenic and mutagenic principles in food, particularly cooked meat (Furihata & Matsushima, 1986), the most mutagenic of these compounds being the amino-imidazoaza-arenes:2amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx...

Caffeine and other methylxanthines have been reported to be effective in preventing the need of invasive airway support in cases of respiratory virus-associated apnea. However, the reliability of the reported effect is not known. We report a case of RSV-induced apnea in an infant in which 10mg/kg of intravenous caffeine did not prevent the need for intubation and mechanical ventilation.

Relatively low concentrations of methylxanthines increase spontaneous twitching in cultured muscle fibers; they also cause a second activity, escalation, which is the initiation and undiminished propagation of visible waves. The effect on twitching is abolished by depolarizing concentrations of K(+) or by tetrodotoxin; the effect on escalation is not. Escalation is prevented by removal of exter...

BACKGROUND Methylxanthines are natural and synthetic compounds found in many foods, drinks, pharmaceuticals, and cosmetics. Aside from caffeine, production of many methylxanthines is currently performed by chemical synthesis. This process utilizes many chemicals, multiple reactions, and different reaction conditions, making it complicated, environmentally dissatisfactory, and expensive, especia...