BACKGROUND: The sitting in an awkward posture for a prolonged time may lead to spinal or musculoskeletal disease. It is important to investigate the joint loads at spine while sitting.OBJECTIVE: The purpose of this study was to investigate the joint moment and antero-posterior (AP) reaction force at cervico-thoracic and lumbosacral joint for various sitting postures.METHODS: Twenty healthy males participated in this study. Six sitting postures were defined from three spinal curvatures (slump, flat, and lordosis) and two arm postures (arms-on-chest and arms-forward). Kinematic and kinetic data were measured in six sitting postures from which joint moment and AP reaction force were calculated by inverse dynamics.RESULTS: In the cervico-thoracic joint, joint moment and AP reaction force were greater in slump than the flat and lordosis postures (p< 0.001) and also in arms-forward posture compared to arms-on-chest posture. In the lumbosacral joint, joint moment and AP reaction force were greater in slump than flat and lordotic posture (p< 0.001) but there was no difference between different arm postures. The joint loads (moment and AP reaction force) at the cervico-thoriacic joint were closely related to the head flexion angle (r> 0.86) while those at the lumbosacral joint were correlated to the trunk flexion angle (r> 0.77). In slump posture, the joint moments were close to or over the extreme of the daily life such as sit-to-stand and walking. Consequently, if the slump is continued for a long time, it may cause pain and diseases at the cervico-thoracic and lumbosacral joints.CONCLUSIONS:The results of the study indicated that the lordosis or flat would be better spinal postures. Also, keeping arms close to body would be desirable to reduce joint loads.

This study aims at the quantification of fine change in parkinsonian rigidity at the wrist during deep brain stimulation (DBS) using a portable measurement system and objective mechanical measures. The rigidity of fourteen limbs was evaluated during DBS surgery. The resistive torque to imposed movement was measured for every setting where a reduction in rigidity was perceived by a neurologist. Quantitative mechanical measures derived from experimental data included viscoelastic properties, work, impulse and mechanical impedance. Most mechanical measures could discriminate the optimal setting from baseline (electrode at stereotactic initial position without electrical stimulation) and the highest significance was achieved by viscous damping constant (p<0.001). Spearman correlation coefficients between mechanical measures and clinical score for multiple settings (averaged for 14 limbs) were 0.51-0.77 and the best correlation was shown for viscosity (ȡ=0.77±0.22). The results suggest that intraoperative quantification of rigidity during DBS surgery is possible with the suggested system and measures, which would be helpful for the adjustment of electrode position and stimulation parameters.

Dynamic changes in spindle structure and function are essential for maintaining genomic integrity during the cell cycle. Spindle dynamics are highly dependent on several microtubule-associated proteins that coordinate the dynamic behavior of microtubules, including microtubule assembly, stability and organization. Here, we show that translationally controlled tumor protein (TCTP) is a novel microtubule-associated protein that regulates spindle dynamics during meiotic maturation. TCTP was expressed and widely distributed in the cytoplasm with strong enrichment at the spindle microtubules during meiosis. TCTP was found to be phosphorylated during meiotic maturation, and was exclusively localized to the spindle poles. Knockdown of TCTP impaired spindle organization without affecting chromosome alignment. These spindle defects were mostly due to the destabilization of the polar microtubules. However, the stability of kinetochore microtubules attached to chromosomes was not affected by TCTP knockdown. Overexpression of a nonphosphorylable mutant of TCTP disturbed meiotic maturation, stabilizing the spindle microtubules. In addition, Plk1 was decreased by TCTP knockdown. Taken together, our results demonstrate that TCTP is a microtubule-associating protein required to regulate spindle microtubule dynamics during meiotic maturation in mouse oocytes.

Patients with scans without evidence of dopaminergic deficits (SWEDDs) show symptoms (e.g., tremors) similar to those of Parkinson's disease (PD) patients, so they are often misdiagnosed. Sensory electrical stimulation (SES) was reported to suppress essential tremor in patients, but SES was never applied to patients with PD and SWEDDs. As the pathophysiological mechanisms of PD and SWEDDs are likely to be different, we hypothesized that the effect of SES would also be different in the two patient groups. This study aimed to test that hypothesis. Fourteen patients with PD and nine with SWEDDs participated in this study. Three wrist muscles were stimulated for 15 s using SES with a stimulation intensity lower than the motor threshold. Angular motion of the index finger was measured via a triaxial gyrosensor before, during, and after stimulation. Outcome measures included the amplitude and peak frequency of the angular motion of the index finger. Tremor amplitude decreased during and after SES in patients with PD (p < 0:05). However, tremor amplitudes during and after SES were not different from the base level in SWEDDs patients. The peak frequency of tremors temporarily decreased during stimulation in PD patients, but not in SWEDDs patients. SES suppressed tremors in patients with PD, but not with SWEDDs. The results could help understand the pathophysiological differences of tremors between PD and SWEDDs.

This paper aims to investigate the effect of continuous sensory electrical stimulation (SES) on the suppression of a Parkinsonian rest tremor. Fourteen patients with Parkinson’s disease participated in this study. Three wrist muscles were electrically stimulated on sensory level under motor threshold. Intensity of stimulation was determined for each muscle of each patient as the maximum tolerable current amplitude that does not induce muscle contraction. Tri-axial gyro sensors were attached to three upper limb segments. The angular velocity of each segment was measured for each of the three sessions, i.e., PRE-, ON- and POST- stimulations. Outcome measures were the tremor amplitude and main frequency of each axis in the power spectrum. Decrease in tremor amplitude was significant at ON and POST sessions in finger and at POST session in hand and forearm. Decrease in main frequency was significant mainly at ON session. About one-third of patients showed reduction in tremor power at ON-stimulation and at POST-stimulation. Subjects with suppression of tremor showed greater initial tremor amplitude than those without suppression. Continuous SES suppressed the Parkinsonian rest tremor. The results suggest that the properties of tremor-generating loop may be altered by continuous SES and the effect lasts temporarily.