Trainability of cold induced vasodilatation in fingers and toes

Subjects that repeatedly have to expose the extremities to cold may benefit from a high peripheral temperature to maintain dexterity and tissue integrity. Therefore, we investigated if repeated immersions of a hand and a foot in cold water resulted in increased skin temperatures. Nine male and seven female subjects (mean 20.4; SD 2.2 years) immersed their right (trained) hand and foot simultaneously in 8°C water, 30 min daily for 15 days. During the pre and post-test (days 1 and 15, respectively) the left (untrained) hand and foot were immersed as well. Pain, tactile sensitivity and skin temperatures were measured every day. Mean (SD) toe temperature of the trained foot increased from 9.49°C (0.89) to 10.03°C (1.38) (p < 0.05). The trained hand, however, showed a drop in mean finger temperature from 9.28°C (0.54) to 8.91°C (0.44) (p < 0.001) and the number of cold induced vasodilation (CIVD) reactions decreased from 52% during the first test to 24% during the last test. No significant differences occurred in the untrained extremities. Pain diminished over time and tactile sensitivity decreased with skin temperature. The combination of less CIVD responses in the fingers after training, reduced finger skin temperatures in subjects that did show CIVD and the reduced pain and tactile sensitivity over time may lead to an increased risk for finger cold injuries. It is concluded that repeated cold exposure of the fingers does not lead to favorable adaptations, but may instead increase the injury risk

Nanotechnology Applications to Improve Solubility of Bioactive Constituents of Foods for Health-Promoting Purposes

Foods-derived multifunctional compounds, such as carotenoids, vitamins, phytosterols, polyunsaturated lipids, curcuminoids, flavonoids and polyphenols, in addition to the basic nutritional value, own extra health benefits and are considered \u201cpharmaceutical-grade nutrients\u201d better known as \u201dnutraceuticals\u201d. Similarly, phytochemicals from plants, characterized by analogous chemical structures, can be considered \u201cpharmaceutical-grade molecules\u201d. They could provide both diseases preventive actions and remarkable therapeutic benefits but, the efforts for identifying their mode of action and for applying them into food industry with health-promoting purposes, are often unsuccessful. Solubility is essential for a good absorption in the gastrointestinal tract and to achieve the systemic concentration necessary for an effective therapeutic activity, but the majority of these compounds are water-insoluble. Consequently, when ingested, they encounter many difficulties in crossing the diverse barriers to reach the bloodstream and to distribute to cells and tissues. Their absorption at gastric or intestinal level is troubled and in addition, they suffer from early degradation or fast metabolism, so rarely they manage to reach the site of action in therapeutically effective concentration and their clinical applications result strongly limited. Toxic excipients and harmful solubilizing agents were and are extensively used for solubilizing and delivering non-soluble bioactive chemicals (BACs) despite the resulting unpleasant side effects complained of by patients. During last decades, several new techniques, often resorting to nanotechnology, aiming at enhancing BACs solubility, at solving their pharmacokinetics drawbacks, at avoiding their early inactivation or fast metabolism, have been developed. On this background, the following chapter provides an overview concerning nanotechnology contribute and its technological advancements in \u201cmanufacturing\u201d nutraceuticals and phytochemicals in more bioavailable nanoparticles. In addition, it is reviewed the involvement of nanoscience in developing and enhancing food-grade solid nanosized materials to be used as BACs \u201ccontainers\u201d and \u201cvehicles\u201d either for their safe and effective oral administration, in the frame of medical treatments, or for achieving smart food ingredients to improve the quality and shelf life of nourishments