Alterations in Postprandial Hepatic Glycogen Metabolism in Type 2 Diabetes

Decreased skeletal muscle glucose disposal and increased endogenous glucose production (EGP) contribute to postprandial hyperglycemia in type 2 diabetes, but the contribution of hepatic glycogen metabolism remains uncertain. Hepatic glycogen metabolism and EGP were monitored in type 2 diabetic patients and nondiabetic volunteer control subjects (CON) after mixed meal ingestion and during hyperglycemic-hyperinsulinemic-somatostatin clamps applying 13C nuclear magnetic resonance spectroscopy (NMRS) and variable infusion dual-tracer technique. Hepatocellular lipid (HCL) content was quantified by 1H NMRS. Before dinner, hepatic glycogen was lower in type 2 diabetic patients (227 ± 6 vs. CON: 275 ± 10 mmol/l liver, P < 0.001). After meal ingestion, net synthetic rates were 0.76 ± 0.16 (type 2 diabetic patients) and 1.36 ± 0.15 mg · kg−1 · min−1 (CON, P < 0.02), resulting in peak concentrations of 283 ± 15 and 360 ± 11 mmol/l liver. Postprandial rates of EGP were ∼0.3 mg · kg−1 · min−1 (30–170 min; P < 0.05 vs. CON) higher in type 2 diabetic patients. Under clamp conditions, type 2 diabetic patients featured ∼54% lower (P < 0.03) net hepatic glycogen synthesis and ∼0.5 mg · kg−1 · min−1 higher (P < 0.02) EGP. Hepatic glucose storage negatively correlated with HCL content (R = −0.602, P < 0.05). Type 2 diabetic patients exhibit 1) reduction of postprandial hepatic glycogen synthesis, 2) temporarily impaired suppression of EGP, and 3) no normalization of these defects by controlled hyperglycemic hyperinsulinemia. Thus, impaired insulin sensitivity and/or chronic glucolipotoxicity in addition to the effects of an altered insulin-to-glucagon ratio or increased free fatty acids accounts for defective hepatic glycogen metabolism in type 2 diabetic patients

Bulk and grain boundary conductivities as function of temperature and oxygen partial pressure of scandia-stabilized zirconia co-doped with yttria and ceria

The electrical properties of bulk and grain boundaries of Ce xY0.2-xSc0.6Zr3.2O 8-δ (0 ≤ × ≤ 0.2) have been investigated as a function of temperature and oxygen partial pressure by application of impedance spectroscopy. All samples have been prepared by means of a sol-gel combustion process. The ionic conductivities of the bulk are in the range from 0.03 to 0.04 S cm-1 at 700°C in air. In the case of ceria-doped samples a significant decrease of the ionic conductivities of both bulk and grain boundary regions is observed under reducing conditions [p(O2) &lt; 10 -15 bar, 700°C] which may be interpreted in terms of association or clustering of oxygen vacancies. In addition, ageing studies have been performed on scandia-stabilized zirconia, doped with 10 mol% Sc 2O3 and 1.0 mol% CeO2, in reducing atmosphere (1%-H2/Ar) at 700°C by application of a dc four-point technique according to van der Pauw and ac measurements.</p

Bulk and grain boundary conductivities as function of temperature and oxygen partial pressure of scandia-stabilized zirconia co-doped with yttria and ceria

The electrical properties of bulk and grain boundaries of Ce xY0.2-xSc0.6Zr3.2O 8-δ (0 ≤ × ≤ 0.2) have been investigated as a function of temperature and oxygen partial pressure by application of impedance spectroscopy. All samples have been prepared by means of a sol-gel combustion process. The ionic conductivities of the bulk are in the range from 0.03 to 0.04 S cm-1 at 700°C in air. In the case of ceria-doped samples a significant decrease of the ionic conductivities of both bulk and grain boundary regions is observed under reducing conditions [p(O2) &lt; 10 -15 bar, 700°C] which may be interpreted in terms of association or clustering of oxygen vacancies. In addition, ageing studies have been performed on scandia-stabilized zirconia, doped with 10 mol% Sc 2O3 and 1.0 mol% CeO2, in reducing atmosphere (1%-H2/Ar) at 700°C by application of a dc four-point technique according to van der Pauw and ac measurements.</p

CD4+ T-cell clones from autoimmune thyroid tissue cannot be classified according to their lymphokine production.

In order to define whether CD4+ T cells from autoimmune and non-autoimmune thyroid tissue could be classified according to their mediator production, lymphokine production was studied in 63 thyroid-derived CD4+ T-cell clones from four patients with Graves' disease, one with Hashimoto's thyroiditis, and one with non-toxic goitre (9-12 clones per patient). The production of interleukin 2 (IL-2), gamma interferon (IFN-gamma), tumour necrosis factor alpha (TNF-alpha), lymphotoxin (LT), interleukin 6 (IL-6) and transforming growth factor beta (TGF-beta) was assessed at the mRNA level by slot-blot analysis in unstimulated clones as well as after activation with monoclonal anti-CD3 (OKT3) and IL-2. No lymphokine production was found in unstimulated clones, whereas 56% of the clones produced all six lymphokines simultaneously after stimulation. In the remaining 44% usually not more than one lymphokine was missing from the complete panel. Lymphokine mRNA concentrations varied between different clones and different patients, but, in this small sample, not between the diseases from which the clones were originated. There was a significant correlation between IL-6, LT, and IL-2 mRNA levels and T-cell helper function, which was estimated by the stimulation of thyroid microsomal autoantibody production using autologous peripheral B cells. TGF-beta and IFN-gamma mRNA expression was unrelated to T-cell help. The results demonstrate that intrathyroid T cells from autoimmune and non-autoimmune thyroid disorders cannot be classified according to their lymphokine production, unlike some results with in vitro-induced mouse T-cell clones, where two populations, Th1 and Th2, have been described. Single T cells are capable of producing a whole panel of lymphokines and thus are capable of triggering a multitude of different processes

Electrical properties of bulk and grain boundaries of scandia-stabilized zirconia co-doped with yttria and ceria

The electrical properties of bulk and grain boundaries of scandia-stabilized zirconia co-doped with yttria and ceria have been determined as a function of temperature (300 &lt; T/°C &lt; 700) and oxygen partial pressure [10− 24 ≤ p(O2)/bar ≤ 1, T = 700 °C] by application of impedance spectroscopy. The yttria and ceria contents of CexY0.2 − xSc0.6Zr3.2O8 − δ (0 ≤ x ≤ 0.2) have been varied systematically. Homogeneous samples have been prepared by means of a sol–gel (glycine-nitrate) combustion process. The ionic conductivity in air is almost independent of composition with typical values around 0.03–0.04 S cm− 1 for the bulk at 700 °C. A significant decrease of the ionic conductivities of bulk and grain boundaries is found for samples co-doped with ceria at low oxygen partial pressures [p(O2) &lt; 10− 15 bar, T = 700 °C]. Activation energies for the ionic transport in oxidizing (air) and reducing (1%-H2/Ar) atmospheres have been extracted from Arrhenius-plots. The oxygen nonstoichiometry in 1%-H2/Ar has been investigated by employing thermogravimetry. The decrease of the ionic conductivity under reducing conditions is accompanied by an increase of the corresponding high temperature activation energy of the bulk, which is interpreted in terms of defect association or clusterin

CD4+ T-cell clones from autoimmune thyroid tissue cannot be classified according to their lymphokine production.

In order to define whether CD4+ T cells from autoimmune and non-autoimmune thyroid tissue could be classified according to their mediator production, lymphokine production was studied in 63 thyroid-derived CD4+ T-cell clones from four patients with Graves' disease, one with Hashimoto's thyroiditis, and one with non-toxic goitre (9-12 clones per patient). The production of interleukin 2 (IL-2), gamma interferon (IFN-gamma), tumour necrosis factor alpha (TNF-alpha), lymphotoxin (LT), interleukin 6 (IL-6) and transforming growth factor beta (TGF-beta) was assessed at the mRNA level by slot-blot analysis in unstimulated clones as well as after activation with monoclonal anti-CD3 (OKT3) and IL-2. No lymphokine production was found in unstimulated clones, whereas 56% of the clones produced all six lymphokines simultaneously after stimulation. In the remaining 44% usually not more than one lymphokine was missing from the complete panel. Lymphokine mRNA concentrations varied between different clones and different patients, but, in this small sample, not between the diseases from which the clones were originated. There was a significant correlation between IL-6, LT, and IL-2 mRNA levels and T-cell helper function, which was estimated by the stimulation of thyroid microsomal autoantibody production using autologous peripheral B cells. TGF-beta and IFN-gamma mRNA expression was unrelated to T-cell help. The results demonstrate that intrathyroid T cells from autoimmune and non-autoimmune thyroid disorders cannot be classified according to their lymphokine production, unlike some results with in vitro-induced mouse T-cell clones, where two populations, Th1 and Th2, have been described. Single T cells are capable of producing a whole panel of lymphokines and thus are capable of triggering a multitude of different processes