34 research outputs found
Efeitos do envelhecimento térmico na microestrutura e na resistência à corrosão do metal de solda de aço AISI 317L
Effects of low temperature aging on the mechanical properties and corrosion resistance of duplex and lean duplex stainless steels UNS S32205 and UNS S32304
Effects of post weld heat treatments on the microstructure and mechanical properties of dissimilar weld of supermartensÃtic stainless steel
Influence of Austenitizing on the Mechanical Properties of Maraging 300 and Sae 4340 Steels - Comparative Study
Effects of food-deprivation and refeeding on the regulation and sources of blood glucose appearance in European seabass (Dicentrarchus labrax L.)
Sources of blood glucose in European seabass (initial weight 218.0 ± 43.0 g; mean ± S.D., n = 18) were
quantified by supplementing seawater with deuterated water (5%-2H2O) for 72 h and analyzing blood glucose
2H-enrichments by 2H NMR. Three different nutritional states were studied: continuously fed, 21-day
of fast and 21-day fast followed by 3 days of refeeding. Plasma glucose levels (mM) were 10.7 ± 6.3 (fed),
4.8 ± 1.2 (fasted), and 9.3 ± 1.4 (refed) (means ± S.D., n = 6), showing poor glycemic control. For all conditions,
2H-enrichment of glucose position 5 was equivalent to that of position 2 indicating that blood glucose
appearance from endogenous glucose 6-phosphate (G6P) was derived by gluconeogenesis. G6P-derived glucose
accounted for 65 ± 7% and 44 ± 10% of blood glucose appearance in fed and refed fish, respectively,
with the unlabeled fraction assumed to be derived from dietary carbohydrate (35 ± 7% and 56 ± 10%, respectively).
For 21-day fasted fish, blood glucose appearance also had significant contributions from
unlabeled glucose (52 ± 16%) despite the unavailability of dietary carbohydrates. To assess the role of hepatic
enzymes in glycemic control, activity and mRNA levels of hepatic glucokinase (GK) and glucose
6-phosphatase (G6Pase) were assessed. Both G6Pase activity and expression declined with fasting indicating
the absence of a classical counter-regulatory stimulation of hepatic glucose production in response to declining
glucose levels. GK activities were basal during fed and fasted conditions, but were strongly stimulated by
refeeding. Overall, hepatic G6Pase and GK showed limited capacity in regulating glucose levels between feeding
and fasting states.The authors
acknowledge financial support from Fundação para a Ciência e
Tecnologia (FCT) in the form of a Ph.D. fellowship to I.V. (SFRH/BD/
41976/2007), and a research grant to J.G.J. (PTDC/EBB-BIO/098111/
2008) and from MICINN (Spain) in the form of a research grant
(BIO2009-07589). The Varian VNMRS 600 MHz spectrometer is supported by the National NMR Network (PTNMR) and was purchased
in the framework of the National Programme for Scientific
Re-equipment, contract REDE/1517/RMN/2005, with funds from
POCI 2010, Fundo Europeu de Desenvolvimento Regional, and FCT