Does Global Astrocytic Calcium Signaling Participate in Awake Brain State Transitions and Neuronal Circuit Function?

We continuously need to adapt to changing conditions within our surrounding environment, and our brain needs to quickly shift between resting and working activity states in order to allow appropriate behaviors. These global state shifts are intimately linked to the brain-wide release of the neuromodulators, noradrenaline and acetylcholine. Astrocytes have emerged as a new player participating in the regulation of brain activity, and have recently been implicated in brain state shifts. Astrocytes display global Ca²⁺ signaling in response to activation of the noradrenergic system, but whether astrocytic Ca²⁺ signaling is causative or correlative for shifts in brain state and neural activity patterns is not known. Here we review the current available literature on astrocytic Ca²⁺ signaling in awake animals in order to explore the role of astrocytic signaling in brain state shifts. Furthermore, we look at the development and availability of innovative new methodological tools that are opening up for new ways of visualizing and perturbing astrocyte activity in awake behaving animals. With these new tools at hand, the field of astrocyte research will likely be able to elucidate the causal and mechanistic roles of astrocytes in complex behaviors within a very near future.

Resistin Gene Expression is Downregulated in CD4(+) T Helper Lymphocytes and CD14(+) Monocytes in Rheumatoid Arthritis Responding to TNF-α Inhibition

Rheumatoid arthritis (RA) is caused by complex interactions between immune cells and sustained by Th1 response cytokines. Resistin [resistance to insulin; (RETN)] is an inflammatory cytokine, first discovered in murine adipocytes. In man, RETN is mainly secreted by monocytes. The distinct role of RETN in the immune reaction is uncertain; however, RETN has pro-inflammatory, pro-fibrotic and possibly tolerogenic properties. The aim was to assess the reaction of RETN gene expression to TNF-α inhibition (I) in pathogenetic immune cell subsets in RA, in the context of Th1, inflammatory and regulatory cytokine gene expressions. Accordingly, we measured RETN, IFN-γ, TNF-β, IL-1β, TNF-α, TGF-β and IL-10 gene expressions in CD14(+) monocytes, CD4(+) T helper (Th) lymphocytes (ly), CD8(+) T cytotoxic (Tc) ly and CD19(+) B ly in active RA before and 3 months after start of TNF-αI. Leucocyte subsets were separated by specific monoclonal antibody-covered beads, RNA extracted and levels of RETN, Th1 response, inflammatory and regulatory cytokine mRNAs measured by quantitative reverse transcription-polymerase chain reaction technique. We found that TNF-αI caused a significant downregulation of RETN gene expression in CD14(+) monocytes and CD4(+) Th ly and was unchanged in CD8(+) Tc ly and CD19(+) B ly. Both in active RA and during TNF-αI, RETN mRNA levels were significantly higher in CD14(+) monocytes than in all other examined cell types. In monocytes, fold change in RETN and TGF-β gene expressions upon TNF-αI correlated significantly. Our findings indicate that RETN has pro-inflammatory as well as proresolving roles in active RA.

The influence of coronene super-hydrogenation on the coronene-graphite interaction

The changes in the strength of the interaction between the polycyclic aromatic hydrocarbon, coronene, and graphite as a function of the degree of super-hydrogenation of the coronene molecule are investigated using temperature programmed desorption. A decrease in binding energy is observed for increasing degrees of super-hydrogenation, from 1.78 eV with no additional hydrogenation to 1.43 eV for the fully super-hydrogenated molecule. Density functional theory calculations using the optB88-vdW functional suggest that the decrease in binding energy is mostly due to an increased buckling of the molecule rather than the associated decrease in the number of π-electrons.

Clinical inertia with regard to intensifying therapy in people with type 2 diabetes treated with basal insulin

AIM

To investigate whether clinical inertia, the failure to intensify treatment regimens when required, exists in people with type 2 diabetes treated with basal insulin.

METHODS

This was a retrospective cohort study involving patients with type 2 diabetes in the UK Clinical Practice Research Datalink database between January 2004 and December 2011, with follow-up until December 2013.

RESULTS

A total of 11 696 patients were included in the analysis. Among all patients, 36.5% had their treatment intensified during the study period; of these, the treatment of 50.0, 42.5 and 7.4% was intensified with bolus or premix insulin or glucagon-like peptide-1 receptor agonists, respectively. The median time from initiation of basal insulin to treatment intensification was 4.3 years [95% confidence interval (CI) 4.1, 4.6]. Among patients clinically eligible for treatment intensification [glycated haemoglobin (HbA1c) ≥7.5% (58 mmol/mol)], 30.9% had their treatment regimen intensified. The median time to intensification in this group was 3.7 years (95% CI 3.4, 4.0). Increasing age, duration of diabetes, oral antihyperglycaemic agent usage and Charlson comorbidity index score were associated with a significant delay in the time to intensification (p < 0.05). Among patients with HbA1c ≥7.5% (58 mmol/mol), 32.1% stopped basal insulin therapy.

CONCLUSIONS

Strategies should be developed to increase the number of patients undergoing therapy intensification and to reduce the delay in intensifying therapy for suitable patients on basal insulin. Initiatives to support patients continuing on insulin are also required.

Analyzing the Case for Bifunctional Catalysis

Bifunctional coupling of two different catalytic site types has often been invoked to explain experimentally observed enhanced catalytic activities. We scrutinize such claims with generic scaling-relation-based microkinetic models that allow exploration of the theoretical limits for such a bifunctional gain for several model reactions. For sites at transition-metal surfaces, the universality of the scaling relations between adsorption energies largely prevents any improvements through bifunctionality. Only the consideration of systems that involve the combination of different materials, such as metal particles on oxide supports, offers hope for significant bifunctional gains.

A Pilot Study on the Influence of Facial Expression on Measurements in Three-Dimensional Digital Surfaces of the Face in Infants With Cleft Lip and Palate

OBJECTIVE

Three-dimensional surface imaging is an increasingly popular modality for face measurements in infants with cleft lip and palate. Infants are noncompliant toward producing specific facial expressions, and selecting the appropriate moment of acquisition is challenging. The objective was to estimate amount and spatial distribution of deformation of the face due to facial expression in infants with cleft lip and palate and provide recommendations for an improved acquisition protocol, including a method of quality control in terms of obtaining images with true neutral expression.

MATERIAL AND METHODS

Three-dimensional surface images of ten 4-month-old infants with unrepaired cleft lip and palate were obtained using a 3dMDface stereophotogrammetric system. For each subject, five surface images judged as representing a neutral expression were obtained during the same photo session. Mean and maximum deformations were calculated. A formalized review was performed, allowing the image exhibiting the "best" neutral expression to be selected, thus decreasing errors due to residual facial expression.

RESULTS

Deformation due to facial expression generally increased from forehead to chin. The amount of deformation in three selected regions were determined: nose (mean, 1 mm; maximum = 3 mm); cleft region (mean, 2 mm; maximum = 5 mm); chin region (mean, 5 mm; maximum = 12 mm). Analysis indicated that introduction of a formalized review of images could reduce these errors by a factor of 2.

CONCLUSIONS

The continuous change of facial expression in infants represents a substantial source of error; however, this may be reduced by incorporating a formalized review into the acquisition protocol.

The activity of satellite cells and myonuclei following 8 weeks of strength training in young men with suppressed testosterone levels

AIM

To investigate how suppression of endogenous testosterone during an 8-week strength training period influences the activity of satellite cells and myonuclei.

METHODS

Twenty-two moderately trained young men participated in this randomized, placebo-controlled, and double-blinded intervention study. The participants were randomized to treatment with a GnRH analogue, goserelin (n = 12), which suppresses testosterone or placebo (n = 10) for 12 weeks. The strength training period of 8 weeks started after 4 weeks of treatment and included exercises for all major muscles. Biopsies were obtained from the mid-portion of the vastus lateralis muscle.

RESULTS

Testosterone resting level in goserelin was 10-20 times lower compared with placebo, and the training-induced increase in the level of testosterone was abolished in goserelin. Training increased satellite cells number in type II fibres by 20% in placebo and by 52% in goserelin (P < 0.01), whereas the myonuclear number significantly increased by 12% in type II fibres in placebo and remained unchanged in goserelin (P < 0.05). No changes in satellite cells and myonuclei were seen in type I fibres in either group. Data from the microarray analysis indicated that low testosterone affects the bone morphogenetic proteins signalling, which might regulate proliferation vs. differentiation of satellite cells.

CONCLUSION

Eight weeks of strength training enhances the myonuclear number in type II fibres, and this is largely blocked by the suppression of testosterone. The data indicate that low testosterone levels could reduce the differentiation of satellite cells to myonuclei via the bone morphogenetic proteins signalling pathway, resulting in reduced increases in lean leg mass.

Peak muscle mass in young men and sarcopenia in the ageing male

SUMMARY

The prevalence of sarcopenia increases with age. The diagnosis of sarcopenia relies in part on normative data on muscle mass, but these data are lacking. This study provides population-based reference data on muscle mass in young men, and these results may be used clinically for the diagnosis of sarcopenia in men.

INTRODUCTION

The ageing population increases the prevalence of sarcopenia. Estimation of normative data on muscle mass in young men during the peak of anabolic hormones is necessary for the diagnosis of sarcopenia in ageing males. The purposes of this study were to provide population-based reference data on lean body mass (LBM) in young men during the time of peak levels of GH/IGF-1 and testosterone and further to apply the reference data on a population-based sample of men aged 60-74 years to estimate the prevalence of sarcopenia.

METHODS

This is a cross-sectional, population-based single-centre study. Our participants are from random selection of 783 men, aged 20-29 years, and 600 men, aged 60-74 years. LBM was assessed by dual-energy X-ray absorptiometry (DXA). LBM T-scores were calculated on the basis of LBM in the young participants. Muscle function in the lower extremities was measured using a leg extension power (LEP) rig in the ageing participants.

RESULTS

Total lean body mass (TLB) was (mean (SD)) 64.7 kg (6.8) in the young and 60.4 kg (6.4) in the ageing men (p<0.001). Lower extremity lean mass (LELB) was 22.0 kg (2.6) in the young and 19.2 kg (2.4) in the ageing men (p<0.001). In the ageing men, TLB and LELB T-scores were -0.64 (0.94) and -1.09 (0.94). A total of 4.8 and 8.5% had a TLB or LELB T-score of less than -2 and a LEP in the lowest quartile.

CONCLUSIONS

This study provides population-based reference data on LBM in men, and these data may be used clinically for the diagnosis of sarcopenia.

Improved upper limits on the stochastic gravitational-wave background from 2009-2010 LIGO and Virgo data

Gravitational waves from a variety of sources are predicted to superpose to create a stochastic background. This background is expected to contain unique information from throughout the history of the Universe that is unavailable through standard electromagnetic observations, making its study of fundamental importance to understanding the evolution of the Universe. We carry out a search for the stochastic background with the latest data from the LIGO and Virgo detectors. Consistent with predictions from most stochastic gravitational-wave background models, the data display no evidence of a stochastic gravitational-wave signal. Assuming a gravitational-wave spectrum of Ω_{GW}(f)=Ω_{α}(f/f_{ref})^{α}, we place 95% confidence level upper limits on the energy density of the background in each of four frequency bands spanning 41.5-1726 Hz. In the frequency band of 41.5-169.25 Hz for a spectral index of α=0, we constrain the energy density of the stochastic background to be Ω_{GW}(f)<5.6×10^{-6}. For the 600-1000 Hz band, Ω_{GW}(f)<0.14(f/900  Hz)^{3}, a factor of 2.5 lower than the best previously reported upper limits. We find Ω_{GW}(f)<1.8×10^{-4} using a spectral index of zero for 170-600 Hz and Ω_{GW}(f)<1.0(f/1300  Hz)^{3} for 1000-1726 Hz, bands in which no previous direct limits have been placed. The limits in these four bands are the lowest direct measurements to date on the stochastic background. We discuss the implications of these results in light of the recent claim by the BICEP2 experiment of the possible evidence for inflationary gravitational waves.