Circulating angiopoietin-like protein 8 is independently associated with fasting plasma glucose and type 2 diabetes mellitus

OBJECTIVE

Angiopoietin-like protein 8 (Angptl8) has recently been introduced as a novel adipokine/hepatokine that promotes pancreatic β-cell proliferation and improves glucose tolerance in mouse models of insulin resistance. However, regulation of Angptl8 in human type 2 diabetes mellitus (T2DM) and renal dysfunction has not been determined.

RESEARCH DESIGN AND METHODS

Serum Angptl8 levels were quantified by ELISA in 62 patients with T2DM as compared with 58 nondiabetic subjects in vivo. Within both groups, about half of the patients were on chronic hemodialysis or had an estimated glomerular filtration rate above 50 mL/min/1.73 m(2). Furthermore, we investigated the effect of insulin and differentiation on Angptl8 mRNA expression in 3T3-L1 adipocytes in vitro.

RESULTS

Median [interquartile range] serum Angptl8 levels were higher in patients with T2DM (1.19 [0.37] μg/L) as compared with nondiabetic subjects (1.03 [0.47] μg/L) (P = .005). Furthermore, the adipokine/hepatokine was significantly higher in women (1.21 [0.47] μg/L) as compared with men (1.05 [0.44] μg/L]) (P = .013). In multivariate analysis, fasting glucose and T2DM but not renal function remained independent and positive predictors of circulating Angptl8 even after adjustment for markers of obesity, lipid status, and inflammation (P < .05). Furthermore, Angptl8 mRNA expression was induced by insulin and during adipogenesis in 3T3-L1 adipocytes in vitro.

CONCLUSIONS

Circulating Angptl8 is positively and independently associated with T2DM and fasting glucose in vivo. Furthermore, Angptl8 mRNA expression is induced by insulin and during adipogenesis in 3T3-L1 adipocytes in vitro.

Association of adenosine receptor gene polymorphisms and in vivo adenosine A1 receptor binding in the human brain

Adenosine A1 receptors (A1ARs) and the interacting adenosine A2A receptors are implicated in neurological and psychiatric disorders. Variants within the corresponding genes ADORA1 and ADORA2A were shown associated with pathophysiologic alterations, particularly increased anxiety. It is unknown so far, if these variants might modulate the A1AR distribution and availability in different brain regions. In this pilot study, the influence of ADORA1 and ADORA2A variants on in vivo A1AR binding was assessed with the A1AR-selective positron emission tomography (PET) radioligand [(18)F]CPFPX in brains of healthy humans. Twenty-eight normal control subjects underwent PET procedures to calculate the binding potential BPND of [(18)F]CPFPX in cerebral regions and to assess ADORA1 and ADORA2A single nucleotide polymorphism (SNP) effects on regional BPND data. Our results revealed SNPs of both genes associated with [(18)F]CPFPX binding to the A1AR. The strongest effects that withstood even Bonferroni correction of multiple SNP testing were found in non-smoking subjects (N=22) for ADORA2A SNPs rs2236624 and rs5751876 (corr. Pall<0.05). SNP alleles previously identified at risk for increased anxiety like the rs5751876 T-allele corresponded to consistently higher A1AR availability in all brain regions. Our data indicate for the first time that variation of A1AR availability was associated with ADORA SNPs. The finding of increased A1AR availability in regions of the fear network, particularly in ADORA2A risk allele carriers, strongly warrants evaluation and replication in further studies including individuals with increased anxiety.

[Childhood craniopharyngioma with hypothalamic obesity - no long-term weight reduction due to rehabilitation programs]

BACKGROUND

Severe obesity due to hypothalamic involvement has major impact on prognosis in long-term survivors of childhood craniopharyngioma. The long-term effects of rehabilitation efforts on weight development and obesity in these patients are not analyzed up to now.

PATIENTS AND METHODS

108 patients with childhood craniopharyngioma recruited in HIT Endo before 2001 were included in the study. Long-term weight development (BMI SDS after >10 yrs follow-up) was analyzed in regard to rehabilitation, which was performed in 31 of 108 (29%) patients (one rehabilitation in 4 patients (13%), more than one in 21 patients (68%), 6 patients unknown) in 13 German rehabilitation -clinics.

RESULTS

84% of patients underwent rehabilitation in order to reduce hypothalamic obesity (BMI>+ 2 SD), whereas 12% of patients were normal weight. Childhood craniopharyngioma pa-tients with rehabilitation presented with higher BMI at diagnosis (median BMI: +1.32 SD; range: -1.08 to + 7.00 SD) and at last evaluation (median BMI: +4.93 SD; range: -0.20 to + 13.13 SD) when compared with patients without rehabilitation (median BMI at diagnosis: +0.24 SD; range: -2.67 to + 6.98 SD; BMI at evaluation: +2.09 SD; range: -1.48 to + 10.23 SD). A long-term weight reducing effect of rehabilitation was no detectable regardless of degree of obesity, frequency of rehabilitation, and hospital of rehabilitation.

CONCLUSION

Treatment options for hypothalamic obesity in terms of rehabilitation are limited. Accordingly, strategies for prevention of hypothalamic lesions and psychosocial effects of rehabilitation are currently in focus for improvement of prognosis in childhood craniopharyngioma patients.

Simulation of thermal fluid dynamics in parabolic trough receiver tubes with direct steam generation using the computer code ATHLET

In the present feasibility study the system code ATHLET, which originates from nuclear engineering, is applied to a parabolic trough test facility. A model of the DISS (DIrect Solar Steam) test facility at Plataforma Solar de Almería in Spain is assembled and the results of the simulations are compared to measured data and the simulation results of the Modelica library “DissDyn”. A profound comparison between ATHLET Mod 3.0 Cycle A and the “DissDyn” library reveals the capabilities of these codes. The calculated mass and energy balance in the ATHLET simulations are in good agreement with the results of the measurements and confirm the applicability for thermodynamic simulations of DSG processes in principle. Supplementary, the capabilities of the 6-equation model with transient momentum balances in ATHLET are used to study the slip between liquid and gas phases and to investigate pressure wave oscillations after a sudden valve closure.

Gain Spectroscopy of HVPE-Grown GaN

We report on photoluminescence and optical gain measurements of highly excited GaN crystals grown by hydride vapor physe epitaxy (HVPE). Inelastic scattering processes of excitons dominate the spontaneous emission spectrum under high excitation up to temperatures of 180 K. Towards room temperature phonon-assisted recombination of excitons and free carriers begins to dominate the spectrum. Similar characteristics are observed in temperature-dependent gain measurements.

Childhood craniopharyngioma - changes of treatment strategies in the trials KRANIOPHARYNGEOM 2000/2007

BACKGROUND

Prognosis in childhood cranio-pharyngioma, is frequently impaired due to sequelae. Radical surgery was the treatment of choice for decades. Even at experienced facilities radical surgery can result in hypothalamic disorders such as severe obesity.

OBJECTIVE

We analyzed, whether treatment strategies for childhood craniopharyngioma patients recruited in GPOH studies have changed during the last 12 years.

MATERIALS AND METHODS

We compared the grade of pre-surgical hypothalamic involvement, treatment, degree of resection and grade of surgical hypothalamic lesions between patients recruited in KRANIOPHARYNGEOM 2000 (n=120; 2001-2007) and KRANIOPHARYNGEOM 2007 (n=106; 2007-2012).

RESULTS

The grade of initial hypothalamic involvement was similar in patients treated 2001-2007 and 2007-2012. The realized treatment was more radical (p=0.01) in patients recruited 2001-2007 (38%) when compared with patients treated 2007-2012 (18%). In patients with pre-surgical involvement of anterior/posterior hypothalamic areas, the rate of hypothalamus-sparing operations resulting in no (further) hypothalamic lesions was higher (p=0.005) in patients treated 2007-2012 (35%) in comparison with the 2001-2007 cohort (13%). Event-free-survival rates were similar in both cohorts.

CONCLUSIONS

A trend towards less radical surgical approaches is observed, which was accompanied by a reduced rate of severe hypothalamic lesions. Radical surgery is not an appropriate treatment strategy in patients with hypothalamic involvement. Despite previous recommendations to centralize treatment at specialized centers, a trend towards further decentralization was seen.

Universal method for separating spin pumping from spin rectification voltage of ferromagnetic resonance

We develop a method for universally resolving the important issue of separating spin pumping from spin rectification signals in bilayer spintronics devices. This method is based on the characteristic distinction of spin pumping and spin rectification, as revealed in their different angular and field symmetries. It applies generally for analyzing charge voltages in bilayers induced by the ferromagnetic resonance (FMR), independent of FMR line shape. Hence, it solves the outstanding problem that device-specific microwave properties restrict the universal quantification of the spin Hall angle in bilayer devices via FMR experiments. Furthermore, it paves the way for directly measuring the nonlinear evolution of spin current generated by spin pumping. The spin Hall angle in a Py/Pt bilayer is thereby directly measured as 0.021±0.015 up to a large precession cone angle of about 20°.