Naomi Yamada

The immunological and chemical detection of N-(hexanoyl)phosphatidylethanolamine and N-(hexanoyl)phosphatidylserine in an oxidative model induced by carbon tetrachloride.

Lipid peroxidation products have a high reactivity against the primary amino groups of biomolecules such as aminophospholipids, proteins, and DNA. Until now, many papers have reported about the modification of biomolecules derived from lipid peroxides. Our group has also reported that aminophospholipids, such as phosphatidylethanolamine (PE), can be modified by lipid peroxidation including 13-hydroperoxyoctadecadienoic acid (13-HPODE). The aim of this study was to examine the oxidative stress in vivo by detecting the formation of N-(hexanoyl)phosphatidylethanolamine (HEPE) and N-(hexanoyl)phosphatidylserine (HEPS), a novel hexanoyl adduct, using a liquid chromatography/tandem mass spectrometry (LC/MS/MS) and a monoclonal antibody. Consequently, we observed that the formation of HEPE and HEPS occurred in the red blood cell (RBC) ghosts modified by 13-HPODE and the oxidative stress model induced by carbon tetrachloride (CCl(4)) using LC/MS/MS monitoring hexanoyl ethanolamine (HEEA), a head group of HEPE, and hexanoyl serine (HESE) as a part of HEPS. Furthermore, we obtained a novel type of monoclonal antibody against HEPE. This antibody could recognize HEPE in the liver of rats with oxidative stress in vivo.

Similarities and differences in manual stretching of physical therapists for equinovarus

For equinovarus, a foot condition commonly suffered as a side effect of stroke, sustained muscle stretching is the primary form of treatment, most of which is manually performed by physical therapists (PTs). It is important to identify variations in the execution of manual stretching techniques by PTs for the standardization of therapeutic techniques. In this study, manual stretching motions performed by three PTs on one stroke survivor were analyzed in terms of foot posture and the force and torque applied to the diseased foot, which were measured through a motion capture system and instrumented foot brace. Statistical analyses based on the principal component analysis showed that many of the stretching motions of the PTs were similar in that they served to control the deformed foot. However, individual differences were observed in the force applied to the heel and the inversion and eversion torque around the ankle, suggesting that individual PTs may stretch different muscle groups. Furthermore, there are potential differences in the efficiency of stretching technique execution among PTs.

Muscle Activity Restriction Taping Technique simulates the reduction in foot-ground clearance in the elderly

The reduced foot-ground clearance manifested in the healthy elderly is a major cause of tripping, potentially resulting in the loss of balance and falling. Hence, there is a critical need to study the foot-ground clearance deficiencies in the elderly. However, such studies are limited by the risks posed by experimental conditions to the health and safety of this population. As a solution, the present study proposes a new Muscle Activity Restriction Taping Technique (MARTT) to simulate the reduced foot-ground clearance of the elderly in healthy young adults. MARTT aims to restrict the range of contraction of the tibialis anterior and gastrocnemius muscles involved in the ankles dorsal and plantar flexion, respectively. The effectiveness of MARTT in simulating the reduced foot-ground clearance in continuous walking was verified in three young adults during treadmill and overground walking. The results revealed that MARTT could successfully simulate the reduced clearance, specifically the minimum toe clearance (MTC), and other gait characteristics of the healthy elderly, such as reduced single-support phase, shortened step length, and lower walking speed.

Ankle stretching rehabilitation machine for equinovarus: Design and evaluation from clinical aspects

Three-dimensional stretching is needed to treat equinovarus, which deforms the patients foot to plantarflexion, adduction, and inversion postures. We have prototyped a three-dimensional stretching machine that the patient can use for the treatment of equinovarus by him- or herself. By adopting a cable-driven mechanism with two independently controllable pneumatic actuators, the stretching machine can apply a force to the foot along the dorsiflexion direction as well as the direction combining abduction and eversion. In this study, we verified the effectiveness of a prototype stretching machine for healthy subjects. For evaluation, the muscle stiffness and maximum voluntary contraction (MVC) of plantarflexion were compared immediately before and after stretching and 10 min later. As a result, the MVC decreased after stretching, which is a clinical index for effective stretching.

Patient simulator using wearable robot: Representation of invariant sitting-down and standing-up motions of patients with knee-OA

It is ethically problematic to engage people with impaired motor functions in experiments, wherein they may face severe pain and unacceptable risk of injuries. We developed a wearable robot for healthy adults and its control algorithm to simulate the behaviors of patients with knee osteoarthritis. We focused on invariant motions, which are typically presented for avoiding knee pain. In order to simulate patient movements by a healthy person wearing a robot, we formulated a model motion that represented invariant patient motions. We then determined the output torque of the exoskeletal knee robot such that the wearers motion followed the model motion. The effectiveness of the method was testified for standing-up and sitting-down motions, and some characteristic impaired motions such as body inclination to the healthy side and imbalanced right and left knee angles were manifested by the simulator.

Ankle stretching rehabilitation machine for equinovarus: Automation of eversion and flexion control

Equinovarus is a foot deformity characterized by the patients foot being at rest in an abnormally supinated state. In a clinical setting, physical therapists manually stretch the foot to a pronated state to allow the patient to retain some degree of mobility. Currently, no automated ankle stretching machine is commercially available. To tackle this issue, we have developed an automated stretching machine that controls the eversion and flexion angles of a patients deformed foot using two pneumatic actuators. We designed a proportional and integral (PI) controller to place the foot in the desired dorsiflexed position and performed a user test involving a healthy participant. Even when the initial foot position of the participant was in an equinovarus position, the foot was successfully everted and dorsiflexed to match the desired reference posture via the stretching machine. The average differences between the reference and measured foot angles at the final state were found to be within 2° for both the dorsiflexion and eversion angles. The machine replicated the reference angles with acceptable errors.

Patient simulator using wearable robot to estimate the burden of knee-osteoarthritis patients during sitting-down and standing-up motions

The estimation of the physical burdens from which people with motor impairment suffer helps us establish welfare techniques comprising personal care equipment and assessment of critical risks, such as fall risks. However, the involvement of actual patients in the evaluation and development of this equipment is costly and involves the exposure of patients to long and exhausting experiments. To solve this problem, we developed a robot wearable by a healthy person and the associated control algorithm to simulate typical motions of patients with knee osteoarthritis, which is a common symptom for the elderly and causes pain during movement. To estimate the physical burdens inflicted by knee malfunctions, we computed the knee flexion and extension moment of the simulated patient during the standing-up and sitting-down motions. The moments, estimated under certain conditions, are qualitatively consistent with those considered clinically, which corroborates the validity of our patient simulation techniques.