Skill-Specific Changes in Somatosensory Nogo Potentials in Baseball Players

Athletic training is known to induce neuroplastic alterations in specific somatosensory circuits, which are reflected by changes in somatosensory evoked potentials and event-related potentials. The aim of this study was to clarify whether specific athletic training also affects somatosensory Nogo potentials related to the inhibition of movements. The Nogo potentials were recorded at nine cortical electrode positions (Fz, Cz, Pz, F3, F4, C3, C4, P3 and P4) in 12 baseball players (baseball group) and in 12 athletes in sports, such as track and field events and swimming, that do not require response inhibition, such as batting for training or performance (sports group). The Nogo potentials and Go/Nogo reaction times (Go/Nogo RTs) were measured under a somatosensory Go/Nogo paradigm in which subjects were instructed to rapidly push a button in response to stimulus presentation. The Nogo potentials were obtained by subtracting the Go trial from the Nogo trial. The peak Nogo-N2 was significantly shorter in the baseball group than that in the sports group. In addition, the amplitude of Nogo-N2 in the frontal area was significantly larger in the baseball group than that in the sports group. There was a significant positive correlation between the latency of Nogo-N2 and Go/Nogo RT. Moreover, there were significant correlations between the Go/Nogo RT and both the amplitude of Nogo-N2 and Nogo-P3 (i.e., amplitude of the Nogo-potentials increases with shorter RT). Specific athletic training regimens may induce neuroplastic alterations in sensorimotor inhibitory processes.     

Aggregatibacter actinomycetemcomitans induces detachment and death of human gingival epithelial cells and fibroblasts via elastase release following leukotoxin‐dependent neutrophil lysis

Aggregatibacter actinomycetemcomitans is considered to be associated with periodontitis. Leukotoxin (LtxA), which destroys leukocytes in humans, is one of this bacterium's major virulence factors. Amounts of neutrophil elastase (NE), which is normally localized in the cytoplasm of neutrophils, are reportedly increased in the saliva of patients with periodontitis. However, the mechanism by which NE is released from human neutrophils and the role of NE in periodontitis is unclear. In the present study, it was hypothesized that LtxA induces NE release from human neutrophils, which subsequently causes the breakdown of periodontal tissues. LtxA‐treatment did not induce significant cytotoxicity against human gingival epithelial cells (HGECs) or human gingival fibroblasts (HGFs). However, it did induce significant cytotoxicity against human neutrophils, leading to NE release. Furthermore, NE and the supernatant from LtxA‐treated human neutrophils induced detachment and death of HGECs and HGFs, these effects being inhibited by administration of an NE inhibitor, sivelestat. The present results suggest that LtxA mediates human neutrophil lysis and induces the subsequent release of NE, which eventually results in detachment and death of HGECs and HGFs. Thus, LtxA‐induced release of NE could cause breakdown of periodontal tissue and thereby exacerbate periodontitis.     

Conformational analysis of the polar head group in phosphatidylcholine bilayers: a structural change induced by cations

The conformation of the polar head group of phosphatidylcholine in a bilayer in the liquid-crystalline state was deduced by analyzing the deuterium quadrupole splittings of the choline group and the phosphorus chemical shift anisotropy of the phosphate group in combination with the restriction of the choline conformation determined in laser Raman studies. The latter efficiently reduced the number of candidates for the actual conformation. A family of conformations was obtained for both the dynamic-structure and rigid-structure models, respectively. The polar head group is oriented roughly parallel to the membrane surface in both models. Furthermore, they are close to conformation A of the crystal structure of 1,2-dimyristoyl-sn-glycero-3-phosphocholine. The dynamic-structure model was concluded to be more reasonable in view of the fact that the polar head-group structures in most crystals comprise two conformations, which are nearly mirror images of each other. Conformational analysis was also carried out for the polar head group in the presence of multivalent cations. A possible conformational change of the polar head group induced by cations is discussed in the light of the present results.     

Cutting edge: inhibition of experimental tumor metastasis by dendritic cells pulsed with alpha-galactosylceramide.

A unique lymphoid lineage, Valpha14 NKT cells, bearing an invariant Ag receptor encoded by Valpha14 and Jalpha281 gene segments, play crucial roles in various immune responses, including protective immunity against malignant tumors. A specific ligand of Valpha14 NKT cells is determined to be alpha-galactosylceramide (alpha-GalCer) which is presented by the CD1d molecule. Here, we report that dendritic cells (DCs) pulsed with alpha-GalCer effectively induce potent antitumor cytotoxic activity by specific activation of Valpha14 NKT cells, resulting in the inhibition of tumor metastasis in vivo. Moreover, a complete inhibition of B16 melanoma metastasis in the liver was observed when alpha-GalCer-pulsed DCs were injected even 7 days after transfer of tumor cells to syngeneic mice where small but multiple metastatic nodules were already formed. The potential utility of DCs pulsed with alpha-GalCer for tumor immunotherapy is discussed.     

Design of Strain-Sensing Devices in Microscale by Using Surface Plasmon Polaritons

We have presented a strain-sensing device in microscale by using surface plasmon polaritons and multimode interference effects. The device is numerically investigated by the finite-difference time-domain method. Optimum depths and length of the structure are designed for sensing a strain. The size of the designed structure is several micrometers and is about a thousandth compared with a fiber Bragg grating strain sensor. The sensitivity of the designed structure is 11.34 pm/μ?? that is about ten times larger than that of a fiber Bragg grating strain sensor. The temperature sensitivity of the designed structure is 34.43 pm/ ^°C. This temperature sensitivity is three times larger than that of a fiber Bragg grating strain sensor. Therefore, temperature compensation techniques are needed for the structure. The presented structure has a simple design such as a plasmonic waveguide with a trench structure. The simple structural design device has a capability of being used in micro- and nano-electromechanical systems.     

An essential role of phosphatidylglycerol in the formation of the osmotically stable liposomes of Escherichia coli phospholipids

A temperature sensitive auxotroph of Escherichia coli K-12 requiring unsaturated fatty acids can grow normally at 28 degrees C, but requires an osmotic stabilizer such as a high amount of salt or sugar in the medium for the growth at 42 degrees C. Namely, the apparent osmotic stability of the cells at 28 degrees C and 42 degrees C is quite different. The osmotic properties of liposomes of the phospholipids extracted from these cells were investigated. The osmotically induced volume change of the multilamellar liposomes was examined by the turbidimetric method. The liposomes prepared from cells grown at 28 degrees C can swell and shrink under a wide range of hypo-and hypertonic conditions. However, those from cells grown at 42 degrees C could not swell under hypotonic conditions. These results exhibit a good correlation between the apparent osmotic stability of E. coli cells and the osmotic properties of the liposomes prepared from the extracted total phospholipids. To clarify the role of each phospholipid component, the osmotic properties of the liposomes reconstituted from the purified phospholipid species were further investigated. The results clearly showed that phosphatidylglycerol is the key factor that stabilizes the membranes of E. coli phospholipids against osmotic pressure.