| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Murdolo, Giuseppe, 1966, et al.
(författare)
-
Acute hyperinsulinemia differentially regulates interstitial and circulating adiponectin oligomeric pattern in lean and insulin-resistant, obese individuals
- 2009
-
Ingår i: J Clin Endocrinol Metab. - 1945-7197. ; 94:11, s. 4508-16
-
Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: Hyperinsulinemia emerges as a negative modulator of the circulating high-molecular-weight adiponectin multimers. OBJECTIVES: Here we asked whether, in vivo, acute hyperinsulinemia regulates adiponectin formation and oligomeric complex distribution at the transcriptional or posttranslational level. DESIGN: Nine lean and nine uncomplicated obese males were studied in the postabsorptive state and during a euglycemic-hyperinsulinemic clamp combined with the microdialysis technique. Subcutaneous abdominal adipose tissue biopsies and interstitial and serum samples were taken at baseline and after the hyperinsulinemia. Adiponectin complexes were characterized by nonheating/nonreducing SDS-PAGE. RESULTS: At baseline, serum and interstitial total adiponectin levels were lower (P < 0.01) in obese than in lean subjects primarily due to a reduction of the high-molecular-weight isoforms. After hyperinsulinemia, serum and interstitial total adiponectin was reduced in both groups. The degree of adiponectin reduction was more prominent in interstitial fluid than in serum. Lean individuals showed an equal suppression of the high-, low-, and middle-molecular-weight adiponectin complexes both in serum and in situ (P < 0.01 vs. basal). In obese subjects, despite the lower interstitial adiponectin subfractions, insulin challenge reduced significantly the circulating middle-molecular-weight forms only. At the mRNA level, adiponectin and its receptors 1 and 2, as well as the abundance of the endoplasmic reticulum chaperone proteins ERp44 and Epsilonro1-Lalpha were similar within the groups, before and after the clamp. CONCLUSIONS: In human obesity, the impaired adiponectin oligomeric pattern in the circulation is mimicked at the tissue level, and hyperinsulinemia may differentially affect the compartmental distribution of the adiponectin complexes.
|
|
| 5. |
- Murdolo, Giuseppe, 1966, et al.
(författare)
-
Insulin differentially modulates the peripheral endocannabinoid system in human subcutaneous abdominal adipose tissue from lean and obese individuals.
- 2007
-
Ingår i: Journal of endocrinological investigation. - 1720-8386. ; 30:8
-
Tidskriftsartikel (refereegranskat)abstract
- Human obesity has been associated with a dysregulation of the peripheral and adipose tissue (AT) endocannabinoid system (ES). The aim of this study was to elucidate the acute in vivo effects of insulin on gene expression of the cannabinoid type 1 (CB-1) and type 2 (CB-2) receptors, as well as of the fatty acid amide hydrolase (FAAH) in the sc abdominal adipose tissue (SCAAT). Nine lean (L) and 9 obese (OB), but otherwise healthy males were studied in the fasting state and during a euglycemic hyperinsulinemic clamp (40 mU/m2 * min(-1)). SCAAT biopsies were obtained at baseline and after 270 min of i.v. maintained hyperinsulinemia. The basal SCAAT gene expression pattern revealed an upregulation of the FAAH in the OB (p=0.03 vs L), whereas similar CB-1 and CB-2 mRNA levels were seen. Following hyperinsulinemia, the FAAH mRNA levels significantly increased approximately 2-fold in the L (p=0.01 vs baseline) but not in the OB. In contrast, insulin failed to significantly change both the adipose CB-1 and CB-2 gene expression. Finally, the FAAH gene expression positively correlated with the fasting serum insulin concentration (r 0.66; p=0.01), whereas an inverse association with the whole-body glucose disposal (r -0.58; p<0.05) was seen. Taken together, these first time observations demonstrate that the ES-related genes in the SCAAT differentially respond to hyperinsulinemia in lean/insulin-sensitive and in obese/insulin-resistant individuals. We suggest that insulin may play a key role in the obesity-linked dysregulation of the adipose ES at the gene level.
|
|
| 6. |
- Murdolo, Giuseppe, 1966, et al.
(författare)
-
Monocyte chemoattractant protein-1 in subcutaneous abdominal adipose tissue: characterization of interstitial concentration and regulation of gene expression by insulin
- 2007
-
Ingår i: J Clin Endocrinol Metab. - : The Endocrine Society. - 0021-972X. ; 92:7, s. 2688-95
-
Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: The chemokine monocyte chemoattractant protein-1 (MCP-1) is implicated in obesity-associated chronic inflammation, insulin resistance, and atherosclerosis. OBJECTIVES: The objectives of this study were to: 1) characterize the interstitial levels and the gene expression of MCP-1 in the sc abdominal adipose tissue (SCAAT), 2) elucidate the response of MCP-1 to acute hyperinsulinemia, and 3) determine the relationship between MCP-1 and arterial stiffness. DESIGN: Nine lean (L) and nine uncomplicated obese (OB) males were studied in the fasting state and during a euglycemic-hyperinsulinemic clamp combined with the microdialysis technique. Interstitial and serum MCP-1 (iMCP-1 and sMCP-1, respectively) levels, pulse wave analysis, and SCAAT biopsies were characterized at baseline and after hyperinsulinemia. RESULTS: OB showed elevated sMCP-1 (P < 0.01) but similar iMCP-1 levels as compared with L. Basal iMCP-1 concentrations were considerably higher than sMCP-1 (P < 0.0001), and a gradient between iMCP-1 and sMCP-1 levels was maintained throughout the hyperinsulinemia. At baseline, SCAAT gene expression profile revealed a "co-upregulation" of MCP-1, MCP-2, macrophage inflammatory protein-1alpha, and CD68 in OB, and whole-body glucose disposal inversely correlated with the MCP-1 gene expression. After hyperinsulinemia, MCP-1 and MCP-2 mRNA levels significantly increased in L, but not in OB. Finally, sMCP-1 excess in the OB positively correlated with the stiffer vasculature. CONCLUSIONS: These observations demonstrate similar interstitial concentrations and a differential gene response to hyperinsulinemia of MCP-1 in the SCAAT from L and OB individuals. In human obesity, we suggest the SCAAT MCP-1 gene overexpression as a biomarker of an "inflamed" adipose organ and impaired glucose metabolism.
|
|
| 7. |
- Sanyal, Biplab, et al.
(författare)
-
Molecular adsorption in defected graphene with divacancy defects
- 2009
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : The American Physical Society. - 1098-0121 .- 1550-235X. ; 79:11, s. 113409-
-
Tidskriftsartikel (refereegranskat)abstract
- We have investigated theoretically the adsorption of molecules onto graphene with divacancy defects. Using ab initio density-functional calculations, we have found that O-2, CO, N-2, B-2, and H2O molecules all interact strongly with a divacancy in a graphene layer. Along with a complex geometry of the molecule-graphene bonding, metallic behavior of the graphene layer in the presence of CO and N-2 molecules has been found with a large density of states in the vicinity of the Fermi level suggesting an increase in the conductivity. The adsorption of N-2 is particularly interesting since the N atoms dissociate in the vicinity of the defects and take the place where the missing C atoms of the divacancy used to sit. In this way, the defected graphene structure is healed geometrically, and at the same time doped with electron states.
|
|
| 8. |
- Widenkvist, Erika, et al.
(författare)
-
Synthesis of Nanostructed Tungsten Oxide Thin Films
- 2008
-
Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 8:10, s. 3750-3753
-
Tidskriftsartikel (refereegranskat)abstract
- A facile and inexpensive method to produce thin films of nanostructured tungsten oxide is described. A nanocrystalline tungstite (WO3·H2O) film is spontaneously formed when a tungsten substrate is immersed in nitric acid at elevated temperatures. The resulting thin film is composed of plate-like tungstite crystals with edges preferentially directed out from the substrate surface. The tungstite can easily be transformed into WO3 by annealing. Patterned WO3·H2O/W structures can be obtained by a combination of lithographic techniques and etching. In this study, the effect of exposure time, acid concentration, and temperature on the microstructure of the films has been investigated. The potential of this inexpensive synthesis method to produce large-area coatings of nanostructured tungsten oxide as well as patterned films makes it interesting for several different applications, such as batteries, gas sensors, and photocatalysts.
|
|
