Phase-specific plasticity of synaptic structures in the somatosensory cortex of living mice during neuropathic pain

<p>Abstract</p> <p>Background</p> <p>Postsynaptic dendritic spines in the cortex are highly dynamic, showing rapid morphological changes including elongation/retraction and formation/elimination in response to altered sensory input or neuronal activity, which achieves experience/activity-dependent cortical circuit rewiring. Our previous long-term <it>in vivo </it>two-photon imaging study revealed that spine turnover in the mouse primary somatosensory (S1) cortex markedly increased in an early development phase of neuropathic pain, but was restored in a late maintenance phase of neuropathic pain. However, it remains unknown how spine morphology is altered preceding turnover change and whether gain and loss of presynaptic boutons are changed during neuropathic pain.</p> <p>Findings</p> <p>Here we used short-term (2-hour) and long-term (2-week) time-lapse <it>in vivo </it>two-photon imaging of individual spines and boutons in the S1 cortical layer 1 of the transgenic mice expressing GFP in pyramidal neurons following partial sciatic nerve ligation (PSL). We found in the short-term imaging that spine motility (Δ length per 30 min) significantly increased in the development phase of neuropathic pain, but returned to the baseline in the maintenance phase. Moreover, the proportion of immature (thin) and mature (mushroom) spines increased and decreased, respectively, only in the development phase. Long-term imaging data showed that formation and elimination of boutons moderately increased and decreased, respectively, during the first 3 days following PSL and was subsequently restored.</p> <p>Conclusions</p> <p>Our results indicate that the S1 synaptic structures are rapidly destabilized and rearranged following PSL and subsequently stabilized in the maintenance phase of neuropathic pain, suggesting a novel therapeutic target in intractable chronic pain.</p

Longevity-associated NADH Dehydrogenase Subunit-2 237 Leu/Met Polymorphism Modulates the Effects of Daily Alcohol Drinking on Yearly Changes in Serum Total and LDL Cholesterol in Japanese Men

Reduced nicotinamide adenine dinucleotide (NADH) dehydrogenase subunit 2 237 leucine/methionine (ND2-237 Leu/Met) polymorphism, is reportedly associated with longevity in the Japanese population. The ND2-237Met genotype may exert resistance to atherogenic diseases, such as myocardial infarction or cerebrovascular disorders. To investigate whether ND2-237 Leu/Met polymorphism is associated with yearly changes in serum lipid levels, we conducted a longitudinal study of 107 healthy Japanese male subjects. Analysis of covariance revealed that the interaction between the ND2-237 Leu/Met genotypes and habitual drinking was significantly associated with yearly changes in serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDLC) levels (p0.036 and p0.006, respectively). In multiple regression analysis, daily drinking was significantly and positively associated with yearly changes in serum LDLC levels in men with ND2-237Met (p0.026). After adjusting for covariates, yearly changes in serum LDLC levels were significantly lower in non-daily drinkers with ND2-237Met than in those with ND2-237Leu (p0.047). These results suggest that ND2-237Met has a beneficial impact on yearly changes in serum LDLC in non-daily drinkers but not in daily drinkers.</p

Translocation of caveolin regulates stretch-induced ERK activity in vascular smooth muscle

Kawabe, J; Okumura, S; Lee, MC; Sadoshima, J; Ishikawa, Y, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 286(5), H1845-H1852, 2004. "Copyright 2004 by the American Physical Society." publisherMechanical stress contributes to vascular disease related to hypertension. Activation of ERK is key to mediating cellular proliferation and vascular remodeling in response to stretch stress. However, the mechanism by which stretch mediates ERK activation in the vascular tissue is still unclear. Caveolin, a major component of a flasklike invaginated caveolae, acts as an adaptor protein for an integrin-mediated signaling pathway. We found that cyclic stretch transiently induced translocation of caveolin from caveolae to noncaveolar membrane sites in vascular smooth muscle cells (VSMCs). This translocation of caveolin was determined by detergent solubility, sucrose gradient fractionation, and immunocytochemistry. Cyclic stretch induced ERK activation; the activity peaked at 5 min (the early phase), decreased gradually, but persisted up to 120 min (the late phase). Disruption of caveolae by methyl-β-cyclodextrin, decreasing the caveolar caveolin and accumulating the noncaveolar caveolin, enhanced ERK activation in both the early and late phases. When endogenous caveolins were downregulated, however, the late-phase ERK activation was subsided completely. Caveolin, which was translocated to noncaveolar sites in response to stretch, is associated with β_1-integrins as well as with Fyn and Shc, components required for ERK activation. Taken together, caveolin in caveolae may keep ERK inactive, but when caveolin is translocated to noncaveolar sites in response to stretch stress, caveolin mediates stretch-induced ERK activation through an association with β_1-integrins/Fyn/Shc. We suggest that stretch-induced translocation of caveolin to noncaveolar sites plays an important role in mediating stretch-induced ERK activation in VSMCs

High-performance Ge/Si electro-absorption optical modulator up to 85°C and its highly efficient photodetector operation

We studied a high-speed Ge/Si electro-absorption optical modulator (EAM) evanescently coupled with a Si waveguide of a lateral p–n junction for a high-bandwidth optical interconnect over a wide range of temperatures from 25 °C to 85 °C. We demonstrated 56 Gbps high-speed operation at temperatures up to 85 °C. From the photoluminescence spectra, we confirmed that the bandgap energy dependence on temperature is relatively small, which is consistent with the shift in the operation wavelengths with increasing temperature for a Ge/Si EAM. We also demonstrated that the same device operates as a high-speed and high-efficiency Ge photodetector with the Franz-Keldysh (F-K) and avalanche-multiplication effects. These results demonstrate that the Ge/Si stacked structure is promising for both high-performance optical modulators and photodetectors integrated on Si platforms

Robust finger motion classification using frequency characteristics of surface electromyogram signals

Finger motion classification using surface electromyogram (EMG) signals is currently being applied to myoelectric prosthetic hands with methods of pattern classification. It can be used to classify motion with great accuracy under ideal circumstances. However, the precision of classification falling to change the quantity of EMG feature with muscle fatigue has been a problem. We addressed this problem in this study, which was aimed at robustly classifying finger motion against changes in EMG features with muscle fatigue. We tested the changes in EMG features before and after muscle fatigue and propose a robust feature that uses a methods of estimating tension in finger motion by taking muscle fatigue into consideration. © 2012 IEEE