Instrumentelle Bioanalytik

Vitamins E plus C and interacting conutrients required for optimal health

“…This was reflected in both sexes significantly by 50% lower plasma levels of the hydroxycarotenoids lutein/zeaxanthin, of about 30-40% lower α/β-cryptoxanthin, and of about 30% lower α-carotene (p < 0.001) but not of β-carotene, lycopene, α-tocopherol, and not of vitamin A. Whereas this study [42] failed to find statistical significance for a 4% lower plasma α-tocopherol/cholesterol ratio in men of Belfast (p = 0.35) the following PRIME Study, a comparison between the middle-aged male working population of Belfast and three French cities (Toulouse, Strasbourg and Lille) analyzing a randomized subset with quality-controlled plasma assay procedures [43], found again the significantly lower (p < 0.05) α-tocopherol/cholesterol ratio in Belfast in comparison to France as initially described in the Vitamin Substudy of the WHO/MONICA Project and as reconfirmed in the above mentioned Comparison between Naples and Bristol [239]. It would also be very amazing if the great cross-sectional difference in vitamin E intake [75] were not reflected in the α-tocopherol/cholesterol ratio: the mean vitamin E intake in France is with 20.4 mg per day (63% from vegetable oils, mainly sunflower seed oil) 71% higher than 12 mg in Britain (81% from soybean oil which might even increase the vitamin E requirement [224]).…”

“…It would also be very amazing if the great cross-sectional difference in vitamin E intake [75] were not reflected in the α-tocopherol/cholesterol ratio: the mean vitamin E intake in France is with 20.4 mg per day (63% from vegetable oils, mainly sunflower seed oil) 71% higher than 12 mg in Britain (81% from soybean oil which might even increase the vitamin E requirement [224]). The Prime Study [43] reconfirmed the substantially lower plasma levels of lycopene and of hydroxycarotenoids between Northern Ireland and France which did apparently not primarily depend on seasonal variations. Interestingly, looking in American men and women for positive correlations between plasma vitamin E and individual carotenoids the strongest correlation was found for lutein [242].…”

“…Correspondingly, the risk of premature death is inversely related to the estimated dietary intake of principal dietary antioxidants, i.e., of vitamin A [32], of vitamin C [3,8,17,18,21,28,[33][34][35][36], and of vitamin E [3,21,26,33,[36][37][38]. This is also true for the vitamin A precursors α-and β-carotene and/or of carotene as representative of total carotenoids or just of fruits and vegetables [4,5,11,28,33,36,[39][40][41] as well as of non-provitamin A carotenoids such as the hydroxycarotenoid lutein and zeaxanthin [9][10][11]42,43] or of lycopene, an extensively conjugated polyene with greatest singlet oxygen quenching properties [44]. Common phenolic antioxidants, e.g., flavonols such as quercetin, may behave correspondingly [45].…”

Insulin receptor activation inhibits insulin secretion from human islets of Langerhans

“…Human islets were transferred to Swinnex chambers (Millipore, Bedford, MA, USA) containing 1 Wm pore-size nylon ¢lters and perifused at a £ow rate of 0.5 ml/min at 37³C in a temperature-controlled environment. Islets were initially perifused with a physiological bu¡er [22] containing 2 mM glucose for 1 h and insulin secreted from the islets into the perifusate during this period was discarded. Islets were then perifused with bu¡ers containing 2 or 20 mM glucose, either in the absence or in the presence of 10 WM L-783,281 (Merck Research Laboratories, Rahway, NJ, USA).…”

Structural transformations in austenitic stainless steel induced by deuterium implantation: irradiation at 100 K

“…At the same time, several studies have shown that martensite formation is responsible for hydrogen-enhanced crack growth, which results in quasi-cleavage fracture of specimens tested in hydrogen [37,38]. Gey and co-workers [39] found that the amount of strain-induced ε -and α *-martensite in AISI 304 steel (Pittsburgh, PA, USA) was strongly dependent on the local mutual orientations of neighboring grains, i.e., texture of the γ steel.…”