RESUMO
Salerno in southern Italy is regarded as the birthplace of modern European university medicine. A practical and scientifically oriented medical discipline developed from monastic and monastery medicine. The Salernitan school, which considered itself as "Civitas Hippocratica", was based initially on the traditions of Hippocrates, the Alexandrian doctors and Galen. In the 11th century a new era began with Constantinus Africanus, who translated the scripts of Greco-Arabic medicine into Latin. By the 12th century, nearly the entire literature by Aristotle, Hippocrates, Galen, Avicenna and Rhazes was available in Latin. Salerno became an important medical training centre - for women and men - with a fixed course curriculum and provided a public health system. Medical training was firmly established under Emperor Friedrich II who placed it under state supervision.
Assuntos
Médicos/história , Faculdades de Medicina/história , Universidades/história , Feminino , História da Medicina , História Medieval , Humanos , Itália , Masculino , MedicinaRESUMO
The popular use of antioxidative vitamins illustrates the growing awareness of oxidative stress as an important hazard to our health and as an important factor in the ageing process. Superoxide radicals and superoxide-derived reactive oxygen species (ROS) are constantly formed in most cells and tissues. To ensure that ROS can function as biological signaling molecules without excessive tissue damage, ROS are typically scavenged by antioxidants such as glutathione and the vitamins A, C, and E. "Oxidative stress" occurs if the production of ROS is abnormally increased or antioxidant concentrations are decreased. Genetic studies in mice, Drosophila, and C.elegans suggested that ageing may be mechanistically linked to oxidative stress. Several manifestations of oxidative stress were shown to increase with age, whereas tissue levels of vitamin E, plasma concentrations of vitamin C, and intracellular glutathione concentrations decrease with age. In at least two independent studies, cysteine supplementation on top of the normal protein diet has shown significant beneficial effects on each of several different parameters relevant to ageing, including skeletal muscle functions. As the quality of life in old age is severely compromised by the loss of skeletal muscle function, and as muscle function can be measured with satisfactory precision, loss of muscle function is one of the most attractive surrogate parameters of ageing. The mechanisms by which a deficit in glutathione and its precursor cysteine contributes to various ageing-related degenerative processes appears to be related largely but not exclusively to the dysregulation of redox-regulated biological signaling cascades.
Assuntos
Envelhecimento/metabolismo , Sistemas de Liberação de Medicamentos/métodos , Compostos de Sulfidrila/metabolismo , Envelhecimento/efeitos dos fármacos , Animais , Humanos , Peso MolecularRESUMO
Insulin signaling is enhanced by moderate concentrations of reactive oxygen species (ROS) and suppressed by persistent exposure to ROS. Diabetic patients show abnormally high ROS levels and a decrease in insulin reactivity which is ameliorated by antioxidants, such as N-acetylcysteine (NAC). A similar effect of NAC has not been reported for non-diabetic subjects. We now show that the insulin receptor (IR) kinase is inhibited in cell culture by physiologic concentrations of cysteine. In two double-blind trials involving a total of 140 non-diabetic subjects we found furthermore that NAC increased the HOMA-R index (derived from the fasting insulin and glucose concentrations) in smokers and obese patients, but not in nonobese non-smokers. In obese patients NAC also caused a decrease in glucose tolerance and body fat mass. Simultaneous treatment with creatine, a metabolite utilized by skeletal muscle and brain for the interconversion of ADP and ATP, reversed the NAC-mediated increase in HOMA-R index and the decrease in glucose tolerance without preventing the decrease in body fat. As the obese and hyperlipidemic patients had lower plasma thiol concentrations than the normolipidemic subjects, our results suggest that low thiol levels facilitate the development of obesity. Supplementation of thiols plus creatine may reduce body fat without compromising glucose tolerance.