Feasibility and outcomes of a community-based, mobile health system-monitored lifestyle intervention in chronic stroke: A pilot study

BACKGROUND

People with disabilities face challenges in daily life during the COVID-19 pandemic, including limited access to care, exposure to lifestyle-related diseases, and difficulties in regular exercise. Therefore, it is important to establish health safety nets using Information and Communication Technology (ICT) in communities.

OBJECTIVE

This study aimed to develop an m-Health-based personalized lifestyle intervention algorithm targeting high-risk groups of lifestyle-related diseases (including hypertension, diabetes, and obesity) among people with hemiplegic disabilities, and to verify its feasibility.

METHODS

Six people at a high risk of lifestyle-related diseases participated in an 8-week lifestyle intervention using a wearable device and the S-Health program. The self-health management areas included walking, moderate-intensity exercise, weight, blood pressure, blood sugar, diet, calorie intake, heart rate, sobriety, no smoking. Health, physical, psychological, and social changes were measured before and after the study.

RESULTS

The intervention had a positive impact on the participants' health, with statistically significant differences found in fasting blood glucose, highest systolic blood pressure, grip strength, and motor function assessment. Quality of life, health-related quality of life, and self-efficacy improved post-intervention.

CONCLUSION

Our findings can be used as preliminary evidence for establishing m-Health-based health safety net systems for people with disabilities who live in communities.

Correlations between ADL in patients with SCI and caregiver burden, quality of life, and presenteeism in South Korea

The correlations between activities of daily living (ADL) among patients with spinal cord injury (SCI) and their caregivers' burden, quality of life (QoL), and presenteeism was investigated. Participants included outpatients and inpatients with SCI at a rehabilitation center and their caregivers, recruited between March 2020 and April 2021. Eighty-seven valid responses were analysed using independent t-tests and Pearson's correlations. There was a difference in caregiver burden according to patients' ADL performance. QoL was negatively correlated with caregiver burden and presenteeism. Caregiver burden and presenteeism were positively correlated. Social support can improve caregivers' QoL and reduce caregiver burden and presenteeism-induced work impairment.

Usability of the novel ankle training equipment with spring resistance-based plantar press exercises in the standing position: A focus on chronic stroke patients with hemiplegic gait

BACKGROUND

To improve gait disability in patients with chronic stroke, ankle muscle strengthening and calf muscle stretching exercises are required. However, currently available ankle training equipment limit ankle exercises based on the position. Recently developed ankle training equipment enables spring resistance-based plantar press exercises to be performed in the standing position with weight support.

OBJECTIVE

To conduct a usability test of the ankle training equipment in the standing position by stroke patients with hemiplegic gait and verify its effects on ankle movements.

METHODS

The ankle training equipment was applied to five patients with chronic stroke and hemiplegic gait. In the standing position, the patients performed forefoot and rearfoot press exercises in the affected side with a day's interval at 20 repetitions maximum (RM). During the exercises, surface electromyography (sEMG) was used to measure the maximum voluntary isometric contraction (%MVIC) of the leg muscles. The System Usability Scale (SUS) was used to assess the ankle training equipment. Wilcoxon signed-rank test was used to evaluate the differences in muscle activity between the two exercises.

RESULTS

Forefoot and rearfoot press exercises increased the %MVIC in the biceps femoris. Additionally, the tibialis anterior and medial gastrocnemius activity was significantly different between the two exercises. The SUS was 78.75% (SD 12.7).

CONCLUSION

The usability test of the passive-control foot press trainer (PFPT) that with improvements in the structure and functions for convenience, it could be commercialized. PFPT could be an alternative to the ankle rehabilitation robot that necessitates a sitting position.

Requirements for Universally Accessible Upper-Body Exercise Equipment: The Case of People with Spinal Cord Injuries in Korea

Background

People with disabilities face considerable obstacles when exercising, which precludes them from the social and health benefits of physical activity. Especially for individuals with paraplegia with spinal cord injuries, it is necessary to maintain continuous participation in physical activity even after discharge, as it helps to maintain mobility and daily living activities through upper body strength. However, the participation rate of people with disabilities in physical activity in Korea is still low, mainly due to the lack of exercise equipment and facilities.

Objectives

The aim of this study is to identify aspects that can be improved for better accessibility to exercise equipment for individuals with paraplegia with spinal cord injuries and to reach a consensus on possible guidelines for accessible exercise equipment.

Methods

This study reviews and evaluated the usability of four existing upper-body exercise equipment for individuals with paraplegia with spinal cord injuries. To assess usability, task performance scores and time were measured, and a survey was conducted on safety and satisfaction. Based on these results, areas for improvement were identified. Through literature review, usability results, and opinions from various stakeholders, eight requirements for universal accessibility were proposed.

Results

It is necessary to consider how wheelchair users access the exercise equipment. The access method to the exercise area (facility regulations, auxiliary equipment to be provided, etc.) and placement of exercise equipment should also be considered. Information such as explanations of the exercise equipment and how to use it should be located within the wheelchair user's field of vision. Considering the participation rate in sports for people with disabilities in Korea, it is necessary to explain the exact exercise equipment and exercise method. It is also necessary to consider how wheelchair users transfer from the wheelchair to the seat of the exercise equipment. Parts that require manipulation of each exercise equipment must be within the wheelchair user's range of motion. Various supports or assistive devices that provide body support according to each piece of equipment are needed. In addition to the wheelchair's own brake, it is necessary to provide a fixing device so that the wheelchair does not move during the exercise.

Conclusion

For people with spinal cord injuries, the arm ergometer, aerobic exercise equipment, showed higher scores in performance, stability, and satisfaction compared to other exercise equipment. Among the strength exercise equipment, shoulder press had an effect on performance, seated lat pull-down had an effect on stability, and seated chest press had an effect on satisfaction. Therefore, when selecting exercise equipment, it is necessary to recommend aerobic and strength exercise equipment according to the preferences of people with spinal cord injuries. When developing strength exercise equipment, it is necessary to consider usability evaluation factors for individuals with spinal cord injury.

Digital Health Equity and Tailored Health Care Service for People With Disability: User-Centered Design and Usability Study

BACKGROUND

As digital health services advance, digital health equity has become a significant concern. However, people with disability and older adults still face health management limitations, particularly in the COVID-19 pandemic. An essential area of investigation is proposing a patient-centered design strategy that uses patient-generated health data (PGHD) to facilitate optimal communication with caregivers and health care service providers.

OBJECTIVE

This study aims to conceptualize, develop, and validate a digitally integrated health care service platform for people with disability, caregivers, and health care professionals, using Internet of Things devices and PGHD to contribute to improving digital health equity.

METHODS

The methodology consists of 5 stages. First, a collaborative review of the previous app, Daily Healthcare 1.0, was conducted with individuals with disabilities, caregivers, and health care professionals. Secondly, user needs were identified via personas, scenarios, and user interface sketches to shape a user-centered service design. The third stage created an enhanced app that integrated these specifications. In the fourth stage, heuristic evaluations by clinical and app experts paved the way for Daily Healthcare 2.0, now featuring Internet of Things device integration. Conclusively, in the fifth stage, an extensive 2-month usability evaluation was executed with user groups comprising individuals with disabilities using the app and their caregivers.

RESULTS

Among the participants, "disability welfare information and related institutional linkage" was the highest priority. Three of the 14 user interface sketches the participants created were related to "providing educational content." The 11 heuristic evaluation experts identified "focusing on a single task" as a crucial issue and advocated redesigning the home menu to simplify it and integrate detailed menus. Subsequently, the app Daily Healthcare 2.0 was developed, incorporating wearable devices for collecting PGHD and connecting individuals with disabilities, caregivers, and health care professionals. After the 2-month usability evaluation with 27 participants, all participants showed an increase in eHealth literacy, particularly those who used the caregiver app. Relatively older users demonstrated improved scores in health IT usability and smartphone self-efficacy. All users' satisfaction and willingness to recommend increased, although their willingness to pay decreased.

CONCLUSIONS

In this study, we underscore the significance of incorporating the distinct needs of individuals with disabilities, caregivers, and health care professionals from the design phase of a digital health care service, highlighting its potential to advance digital health equity. Our findings also elucidate the potential benefits of fostering partnerships between health consumers and providers, thereby attenuating the vulnerability of marginalized groups, even amid crises such as the COVID-19 pandemic. Emphasizing this imperative, we advocate for sustained endeavors to bolster the digital literacy of individuals with disabilities and champion collaborative cocreation, aiming to uphold the collective ethos of health and digital health equity.

Effects of Pilates on inter-recti distance, thickness of rectus abdominis, waist circumference and abdominal muscle endurance in primiparous women

BACKGROUND

Pilates is expected to have a positive effect on women with weakened abdominal muscles after childbirth. Pilates may have a beneficial effect on the structure and function of the abdominal muscles in pregnant women. Therefore, the objective of this study was to investigate the effects of Pilates on inter-recti distance, thickness of the rectus abdominis, waist circumference, and abdominal muscle endurance in primiparous women.

METHODS

Thirty-five primiparous postpartum women were assigned to either the Pilates exercise group (n = 20) or the control group (n = 15). Pilates was undertaken by the exercise group for 50 min/day, 5 days/week, for 4 weeks. The control group maintained their daily activities without any intervention. The inter-recti distance was measured at three locations along the linea alba, and the thickness of the rectus abdominis was measured using ultrasound. Abdominal muscle endurance was measured using a repeated 1-min curl-up test. Waist circumference was also measured.

RESULTS

The exercise group showed significant improvements from baseline in inter-recti distance, waist circumference, and abdominal muscle endurance (p < 0.05). The control group showed no significant improvement in these variables. Compared with the control group, the exercise group showed significantly improved performance in terms of inter-recti distance, waist circumference, and abdominal muscle endurance (p < 0.05).

CONCLUSIONS

The results of this study demonstrate that Pilates was effective in reducing inter-recti distance and waist circumference and improving abdominal muscle endurance in primiparous postpartum women. Pilates is considered an effective exercise for improving muscle structure and function in primiparous postpartum women, helping in the recovery from, and preventing, diastasis rectus abdominis.

Caregiver burden according to ageing and type of care activity in caregivers of individuals with spinal cord injury

OBJECTIVE

To describe caregiver burden according to the caregivers' general characteristics, especially with ageing, and type of care activities provided by caregivers of individuals with spinal cord injury.

DESIGN

A cross-sectional study was conducted utilizing a structured questionnaire that included general characteristics, health conditions, and caregiver burden.

SETTING

A single center study in Seoul, Korea.

SUBJECTS

Participants were recruited from 87 individuals with spinal cord injuries and 87 caregivers.

METHODS

The Caregiver Burden Inventory was used to assess caregiver burden.

RESULTS

Caregiver burden was significantly different by age (p = 0.001), relationship (p = 0.025), sleep hours (p = <0.001), underlying disease (p = 0.018), pain (p = <0.001), and daily activities of individuals with spinal cord injury (p = 0.001). Caregiver's age (B = 0.339, p = 0.049), sleep duration (B = -2.896, p = 0.012) and pain (B = 2.558, p < 0.001) predicted caregiver burden. Toileting assistance was the most challenging and time-consuming for caregivers, while patient transfer was associated with the greatest concerns for body injury.

CONCLUSION

Caregiver education should be targeted according to caregiver's age and type of assistance. Social policies need to be developed to distribute devices and care-robots to reduce caregiver burden and thereby assist caregivers.

Effects of Ving Tsun sticking-hand training on lower limb sensorimotor performance among community-dwelling middle-aged and older adults: a randomized controlled trial

BACKGROUND

To explore the effects of Ving Tsun (VT) sticking-hand training on knee joint proprioception and leg muscular performance among community-dwelling middle-aged and older adults.

METHODS

Thirty-three middle-aged and older adults were randomly assigned to either the VT or control group. The VT group received sticking-hand training twice/week for 3 months. Data were collected before and after the intervention period. The primary outcome was knee joint repositioning error, which was measured using knee joint active repositioning tests. The secondary outcomes included the maximum muscle strength and time to maximum muscle strength of the major leg muscles.

RESULTS

No significant group, time, or group-by-time interaction effects were found for the knee joint repositioning error (p > 0.05). The maximum muscle strength of the knee flexors increased over time in the VT group only (p = 0.038). In addition, the time to maximum muscle strength in the hip extensors and flexors increased over time in both groups (p < 0.05). For the knee extensors and flexors, the time to maximum muscle strength increased in the control (p = 0.027) and VT (p = 0.019) groups, respectively, over time.

CONCLUSIONS

VT sticking-hand training could improve the maximum muscle strength of the knee flexors but could not attenuate the age-related deterioration in leg muscle contraction speed nor improve knee joint proprioception among community-dwelling middle-aged and older adults.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03318289. Registered on 23 October 2017.

Tai chi-muscle power training for children with developmental coordination disorder: a randomized controlled trial

This study compared the effectiveness of tai chi (TC) muscle power training (MPT), TC alone, MPT alone, and no training for improving the limits of stability (LOS) and motor and leg muscular performance and decreasing falls in children with developmental coordination disorder (DCD). One hundred and twenty-one children with DCD were randomly assigned to the TC-MPT, TC, MPT, or control group. The three intervention groups received TC-MPT, TC, or MPT three times per week for 3 months. Measurements were taken before and after the intervention period. The primary outcomes were the LOS completion time and dynamic LOS scores. The secondary outcomes included the Movement Assessment Battery for Children-Second Edition total test score and percentile rank, knee muscle peak force and time to peak force, and the number of falls. None of the interventions affected the LOS test scores. Improvements in the peak forces of the knee extensors and flexors were demonstrated in the TC (p = 0.006) and MPT groups (p = 0.032), respectively. The number of falls also decreased in these two groups (p < 0.001). Thus, clinicians may prescribe TC or MPT for children with DCD to increase their knee muscle strength and reduce their risk of falls.

A comparative analysis of the work environments for registered nurses, nurse aides, and caregivers using the 5th Korean Working Conditions Survey

BACKGROUND

Since the quality of work life of healthcare workers is affected by various factors, an improvement in their work environment can reduce the burden on them, increasing their performance. This study aimed to identify the current problems in working environments for registered nurses (RNs), nurse aides (NAs), and caregivers using the 5th Korean Working Conditions Survey (KWCS), presenting measures to improve working conditions by analyzing their predictors: 1) degree of exposure to work-related risk factors (musculoskeletal and mental), 2) working patterns, 3) work-family balance, 4) work situations, and 5) self-rated health.

METHODS

The sampling frame was a list of apartment and general survey zones, excluding islands, dormitories, special social facilities, tourist hotels, and foreigner zones, among the total survey zones of the 2010 Population and Housing Census. The KWCS was given to 50,205 participants of various occupations, and responses from 494 RNs, 201 NAs, and 505 caregivers were extracted to compare their 1) degree of exposure to work-related risk factors (musculoskeletal and mental), 2) working pattern, 3) work-family balance, 4) work situations, and 5) self-rated health.

RESULTS

The response rate was 0.449. There were significant differences in all the variables (exposure to musculoskeletal and mental work-related risk factors, working pattern, work-family balance, work situations, self-rated health, and satisfaction with working conditions) among RNs, NAs, and caregivers (p < 0.001). The degree of work-related musculoskeletal and mental risk exposure was higher among caregivers and RNs than among NAs; irregular working patterns, challenges with work-family balance, and work environment satisfaction were higher among caregivers than among NAs. In addition, work situations were poorer among caregivers and NAs than among RNs. Self-rated health was the highest among caregivers, followed by RNs and NAs. The most potent predictor of self-rated health was occupation, followed by work environment satisfaction and work-family balance; the most potent predictor of work environment satisfaction was self-rated health, followed by degree of exposure to work-related musculoskeletal and mental risk factors, occupation, work-family balance, work situation, and working patterns.

CONCLUSION

This study confirmed that a variety of factors influence work environment satisfaction. Thus, practical and realistic measures to improve work environments tailored to each healthcare occupation should be developed at the national and community levels. Further qualitative studies are needed to analyze the work environments of nurses and other care workers in depth.

Effect of changing the lying posture angle by changing the bed posture on the average pressure, maximum pressure, and pressure area in the hip region

BACKGROUND: An electric bed can easily change posture from a lying position and was effective in preventing pressure ulcer. OBJECTIVE: This study aimed to identify the optimal posture for the prevention of pressure ulcers by analyzing pressure changes applied to the pelvic region. METHODS: Pressure changes resulting from lateral rotations of the body using an electronic adjustable bed and changes in the posture and angles of the trunk and knees were assessed. Twelve conditions with varying angles of the trunk and knees (15–35∘ in 5∘ increments) and varying lateral angles (20–35∘ in 5∘ increments) were tested. The pressure (maximum and average) and contact area in the pelvic region of 20 individuals without disabilities were calculated. RESULTS: The conditions in which the average and maximum pressures did not increase according to the increase in angle were 25∘ for the upper body and knee angles and 35∘ for the side. CONCLUSIONS: The body pressure changed according to the posture rather than according to physical characteristics. Lateral rotation combined with changes in the angles of the trunk and knees effectively prevented pressure ulcers. Changes in the posture at various angles prevented an increased pressure on the body.

Atypical adaptive postural responses in children with developmental coordination disorder: Implications for rehabilitation

BACKGROUND

Adaptive postural control is an important yet underexamined area in children with developmental coordination disorder (DCD). This study compared adaptive postural responses between children with DCD and those with typical development.

METHODS

This was an exploratory cross-sectional study. Fifty-two children with DCD (aged 6-9 years) and 52 age- and sex-matched children with typical development participated in the study. Their adaptive postural (motor) responses were assessed using the Adaptation Test (ADT) on a computerized dynamic posturography machine. The sway energy score (SES) for each ADT trial and the average SES of five trials for both toes-up and toes-down platform inclination conditions were recorded.

RESULTS

The SESs were lower in the DCD group than in the control group in ADT toes-up trial 1 (p = 0.009) and on average (p = 0.044). In the control group, the SES decreased from trial 1 to trial 2 for both the ADT toes-up (p = 0.005) and toes-down conditions (p < 0.001).

SIGNIFICANCE

Adaptive postural responses were absent in children with DCD, and these children used less force (i.e., sway energy) to overcome postural instability. Therefore, both adaptive balance and neuromuscular training should be factored into rehabilitation programs for children with DCD.

Different Effects of Robot-Assisted Gait and Independent Over-Ground Gait on Foot Plantar Pressure in Incomplete Spinal Cord Injury: A Preliminary Study

Background: There is insufficient evidence to establish the optimal treatment protocol for robot-assisted gait training. Objective: This study aimed to analyze the effects of robot-assisted gait and independent over-ground gait on foot pressure and to determine an effective training protocol for improvement of gait pattern in patients with incomplete spinal cord injury due to industrial accidents. Methods: Four patients with incomplete spinal cord injury due to an industrial accident who had gait disturbance underwent measurement of peak foot pressure and stance phase duration using a foot pressure analysis system with robot-assisted gait and independent over-ground gait. Results: The robot-assisted gait condition has lower peak foot pressure and shorter stance phase duration than the independent over-ground gait. Conclusions: In this study, robot-assisted gait was found to limit gait pattern improvement in patients with gait disturbance caused by incomplete spinal cord injury due to industrial accidents. Therefore, future research will be conducted to determine the optimal protocol for robot-assisted gait training for gait pattern improvement.

Exploratory Analysis of Related Factors with Absenteeism and Presenteeism on Workers: Using the Fourth Korea Working Condition Survey

Purpose: This study aimed to identify the factors related to absenteeism and presenteeism in workers and to provide basic evidence to help improve their quality of life and work productivity. Methods: Data from the Fourth Korea working condition survey were analyzed. A stepwise regression model was developed to identify the related factors for exploratory analysis. Results: Absenteeism and subjective risk perception related to work and health conditions were the strongest predictive factors, followed by presenteeism. Fatigue was the strongest predictive factor for presenteeism, followed by a high temperature at the workplace, lower back pain, and other health conditions, in that order. Conclusion: The quality of life and the productivity of workers could be improved by focusing on the factors affecting absenteeism and presenteeism, such as the working environment and health status.

Balance control, agility, eye-hand coordination, and sport performance of amateur badminton players: A cross-sectional study

In this study, balance performance, agility, eye-hand coordination, and sports performance were compared between amateur badminton players and active controls.Thirty young adult badminton players and 33 active controls participated in the study. Static single-leg standing balance (with eyes closed) was measured using a force platform, and dynamic balance was measured using the Y Balance Test (lower quarter). Agility was measured using a hexagon agility test, and eye-hand coordination was measured using a computerized finger-pointing task. Sports performance was quantified by the number of times a shuttlecock fell in a designated area following a badminton serve.The badminton players had superior accuracy in badminton serving (P < .001) relative to the active controls. However, no significant between-group differences were noted in all other outcome variables (P > .05).Amateur badminton players had more favorable sports performance, but not balance performance, agility, or eye-hand coordination, than controls.

A comparison of shoulder muscular performance and lean mass between elite and recreational swimmers: Implications for talent identification and development

This study compared the shoulder muscular performance and lean mass between elite and recreational swimmers.Thirty elite swimmers (mean age ± standard deviation = 23.1 ± 3.5 years) and 21 recreational swimmers (mean age ± standard deviation = 20.8 ± 2.1 years) participated in the study. Maximum muscle strength and time to maximum muscle strength of shoulder flexor, extensor, abductor, and adductor muscles were measured using a handheld dynamometer. Lean mass of the arms and body (excluding the head) were measured using dual-energy x-ray absorptiometry (DXA).Results revealed that compared with recreational swimmers, elite swimmers had higher maximum muscle strength of the shoulder flexor, extensor, abductor, and adductor muscles (all P < .001). The time to reach maximum muscle strength of all shoulder muscles showed no significant difference between the 2 groups (P > .05). The lean mass values in the left arm (P = .037), right arm (P < .001), and whole body (P = .014) were higher in elite swimmers than recreational swimmers.Elite swimmers had greater shoulder maximum muscle strength compared with recreational swimmers though the time taken to reach maximum muscle strength was similar between the 2 groups. Elite swimmers also showed a higher lean mass in both arms and their entire body when compared with recreational swimmers. The results may be useful for recreational swimmers who intend to advance to professional level, and for talent identification and early development of elite swimmers.

Effects of kinesiology taping on shoulder girdle muscle activity and sports performance during badminton forehand overhead strokes in amateur badminton players with shoulder impingement syndrome

BACKGROUND

This study aimed to examine the influence of kinesiology taping (KT), various overhead stroke techniques, and their interactions on shoulder girdle muscle activity and on sports performance in badminton players with shoulder impingement syndrome.

METHODS

Twenty-five amateur badminton players with shoulder impingement syndrome participated in the study. Each was exposed to two KT conditions (no taping and taping) while performing four badminton strokes (defensive clear, attacking clear, smash, and drop shot) in a random order. Surface electromyography (EMG) was used to evaluate the activity of the pectoralis major, anterior deltoid, infraspinatus, and latissimus dorsi muscles. The EMG data are expressed as a percentage of the EMG amplitude recorded during a maximal voluntary isometric contraction of the respective muscles. The shuttlecock speed was also measured via video analysis.

RESULTS

The pectoralis major, anterior deltoid, infraspinatus, and latissimus dorsi EMG amplitudes were greatest during smashes (P<0.05), followed in general by attacking clearances (P<0.05) and defensive clearances (P<0.05). Drop shots induced the lowest EMG amplitudes in the shoulder girdle muscles (P<0.05). No significant main effect of the KT condition or KT-badminton stroke interaction effects were found (P>0.05).

CONCLUSIONS

The use of KT conferred no immediate benefits in improving shoulder girdle muscle activity or sports performance in amateur badminton players with shoulder impingement syndrome. Shoulder girdle muscle activity and sports performance were primarily influenced by the badminton overhead stroke techniques.

Adapted Taekwondo Training for Prepubertal Children with Developmental Coordination Disorder: A Randomized, Controlled Trial

This study evaluated the effectiveness of adapted Taekwondo (TKD) training on skeletal development and motor performance in children with developmental coordination disorder (DCD). One hundred forty-five prepubertal children with DCD were allocated to either the TKD or control groups. Children in the TKD group participated in a weekly 1-hour adapted TKD intervention and daily TKD home exercises for 12 weeks. The primary outcome (delay in skeletal development) and secondary outcomes (Movement Assessment Battery for Children (MABC) total impairment score, eye-hand coordination (EHC) scores, and a standing balance score) were measured at baseline, after the intervention and 3 months after the intervention. Skeletal development improved in both groups over time (p < 0.017). The TKD group had a significant delay in skeletal development at baseline compared to the control group (p = 0.003) but caught up with the controls at 3 months (p = 0.041). Improvements in the MABC scores were also seen in both groups across time (p < 0.017). Only the TKD group had a significant improvement in the EHC movement time at 3 (p = 0.009) and 6 months (p = 0.016). The adapted TKD intervention may be effective in improving the skeletal development and EHC movement time of children with DCD. For motor performance, the effect of maturation might be more profound.

Influence of pelvic padding and Kinesiology Taping on pain perception, kinematics, and kinetics of falls in female volleyball athletes

BACKGROUND

Volleyball digging techniques may cause pelvic injuries among female volleyball athletes. Pelvic padding and Kinesiology Taping (KT) may reduce impact force and pain and improve posture during a fall. This study examined the effects of pelvic padding and KT on pain perception, fall kinematics, and kinetics among female volleyball athletes.

METHODS

Twenty-four female volleyball athletes were exposed to two pelvic padding scenarios (with and without padding) and two KT conditions (with and without KT applied on the rectus abdominis muscle) during a fall in the forward direction. The maximum impact force during landing and maximum acceleration of the pelvis were registered using a force platform and an accelerometer, respectively. The maximum lumbar (hyper) extension angle, forward reach distance, and total fall time were measured by video analysis. Pain level was quantified using a visual analog scale.

RESULTS

The application of pelvic padding (with and without KT) reduced pain when compared to the no padding condition (p < 0.008). Applying KT alone reduced forward reach distance when compared to the 'pelvic padding and KT' condition (p < 0.010). In fact, when both pelvic padding and KT were applied, participants reached further when compared to the 'no pelvic padding and no KT' condition (p < 0.001). No significant main and interaction effects were found in all other outcomes.

CONCLUSIONS

Volleyball shorts with pelvic pads are recommended for female volleyball athletes to reduce pain in the digging maneuver and may help to increase their forward reach distance. However, KT is not recommended as it reduces the forward reach distance and cannot reduce pain or improve fall kinematics and kinetics.

Relationships between presenteeism and work-related musculoskeletal disorders among physical therapists in the Republic of Korea

This study investigated the relationship between presenteeism and work-related musculoskeletal disorders (WMSDs) among physical therapists (PTs) in the Republic of Korea. Questionnaires were given to 600 PTs in the Republic of Korea. General and occupational characteristics and the prevalence of presenteeism and absenteeism were self-reported on the questionnaire. Stepwise regression analyses were used to evaluate the effects of presenteeism and other variables on general and occupational characteristics. Of the 490 PTs who responded, 399 (81.4%) reported at least one WMSD. There was a low incidence rate of absenteeism, but work impairment scores indicate there was a high incidence of presenteeism. In the stepwise regression analyses, the incidence of WMSDs was highest in cases of presenteeism. The results of this study demonstrate that there is a high incidence rate of WMSDs in Republic of Korean PTs, that WMSDs are related to presenteeism and that PTs demonstrate high presenteeism and low absenteeism.

Proprioception and Flexibility Profiles of Elite Synchronized Swimmers

This study compared the full-body flexibility and joint proprioception (on land and underwater) of (a) 20 elite female synchronized swimmers (mean age ± standard deviation = 18.5 ± 1.9 years) and (b) 20 college female swim team members with no training in synchronized swimming (control participants; mean age ± standard deviation = 20.6 ± 1.3 years). Flexibility of the trunk and upper and lower limbs was measured using plastic tape and a goniometer, respectively. Joint proprioception (joint position sense) of the upper and lower limbs on land and underwater was measured by an active joint angle repositioning test. Principle outcome measures were passive joint range of motion (flexibility) and active joint repositioning error (proprioception). Multivariate analysis of covariance revealed that, compared with control swimmers, synchronized swimmers had greater passive joint ranges of motion in the spinal and upper and lower limb joints ( p < .05) and fewer active joint repositioning errors in the shoulder, wrist, and ankle on land ( p < .05) and in the hip and ankle underwater ( p < .05). These results help characterize peak synchronized swimmer capabilities, provide valuable reference details for coaches, and may be useful for talent identification and skill development in this sport.

Comparison of the effects on dynamic balance and aerobic capacity between objective and subjective methods of high-intensity robot-assisted gait training in chronic stroke patients: a randomized controlled trial

BACKGROUND

Robot-assisted gait training (RAGT) is effective for improving dynamic balance and aerobic capacity, but previous RAGT method does not set suitable training intensity. Recently, high-intensity treadmill gait training at 70% of heart rate reserve (HRR) was used for improving aerobic capacity and dynamic balance.

PURPOSE

This study was designed to compare the effectiveness between objective and subjective methods of high-intensity RAGT for improving dynamic balance and aerobic capacity in chronic stroke.

METHODS

Subjects were randomly allocated into experimental (n = 17) and control (n = 17) groups. The experimental group underwent high-intensity RAGT at 70% of HRR, whereas the control group underwent high-intensity RAGT at an RPE of 15. Both groups received their assigned training for 30 min per session, 3 days per week for 6 weeks. All subjects also received an additional 30 min of conventional physical therapy. Before and after each of the 18 sessions, the dynamic balance and aerobic capacity of all subjects were evaluated by a blinded examiner.

RESULTS

After training, Berg Balance Scale (BBS) and Timed Up and Go Test scores, VO₂max, and VO₂max/kg were significantly increased in both groups (p < 0.05). These variables in experimental group were significantly greater than control group. However, the BBS score was not significantly different between both groups. All subjects completed high-intensity RAGT. No adverse effect of training was observed in both groups.

CONCLUSION

High-intensity RAGT at 70% of HRR significantly improved dynamic balance and aerobic capacity more than RAGT at RPE of 15. These results suggest that high-intensity RAGT at 70% of HRR is safe and effective for improving dynamic balance and aerobic capacity in chronic stroke.

Musculoskeletal profile of middle-aged Ving Tsun Chinese martial art practitioners: A cross-sectional study

This cross-sectional exploratory study aimed to quantify and compare the axial and appendicular bone mineral density (BMD), muscle mass, and muscle strength of middle-aged practitioners of Ving Tsun (VT; a hard-style Chinese martial art) with those of nonpractitioners.Eighteen VT practitioners (mean age ± standard deviation = 51.8 ± 17.7 years; 12 men and six women) and 36 active controls (mean age ± standard deviation = 58.7 ± 11.0 years; 18 men and 18 women) participated in the study. All participants underwent a 1-day battery of musculoskeletal examinations. The BMD of the total radius, total hip, femoral neck, and lumbar spine was measured using dual-energy X-ray absorptiometry, as was the lean mass of the arm, leg, and trunk. Muscle strength of the upper and lower limbs was assessed using a Jamar dynamometer and an isokinetic dynamometer at 60°/second, respectively.VT-trained participants had a 11.5% higher total radius BMD (P = 0.023), a 17.8% higher leg lean mass (P = 0.014), a 56.4% higher isokinetic body weight-adjusted peak torque of the knee extensors (P < 0.001), a 60.8% higher isokinetic body weight-adjusted peak torque of knee flexors (P < 0.001), and a 31.4% shorter time to reach peak torque in the knee flexors (P = 0.001) than the active controls. No significant differences were found in any of the other musculoskeletal outcomes between the 2 groups (P > 0.05).Middle-aged VT practitioners displayed a higher total radius BMD and leg lean mass and better knee extensor and flexor muscular performances than their healthy active counterparts. Healthcare professionals may consider using this alternative method of training to improve the musculoskeletal health of middle-aged adults.

Effect of the Schroth method of emphasis of active holding on Cobb's angle in patients with scoliosis: a case report

[Purpose] The purpose of this study was to examine the effect of the Schroth method (three-dimensional convergence exercise) of emphasis of active holding on pain and Cobb's angle in patients with scoliosis. [Subjects and Methods] It applied the Schroth method program of emphasis of active holding individually to three subjects three time per week for 15 weeks. All subject were measured Cobb's angle and pain. [Results] After 15 weeks, pain and Cobb's angle decreased compared to values before. [Conclusion] These results demonstrate the benefit of the Schroth exercise program of emphasis of active holding on decreasing pain and Cobb's angle in patients with idiopathic scoliosis.

Association between Knee Osteoarthritis, Cardiovascular Risk Factors, and the Framingham Risk Score in South Koreans: A Cross-Sectional Study

Background

Osteoarthritis is a significant burden on personal health and for social cost, and its prevalence is rising. Recent research has revealed an association between osteoarthritis and cardiovascular disease, and this study uses the Framingham risk score (FRS), which is widely used as a composite index of cardiovascular risk factors, to investigate the association between osteoarthritis and various cardiovascular risk factors.

Methods

A total 9,514 participants aged 50 years or older who received knee X-ray diagnosis of the 5th Korean National Health and Nutrition Examination Survey (total surveyees = 24,173) released by the Korean Centers for Disease Control and Prevention was included for analysis. Knee osteoarthritis patients were defined as participants with K-L grade ≥2 on knee X-ray regardless of knee pain. The association between major cardiovascular risk factors (blood pressure, diabetes, cholesterol, and smoking habits), FRS, and knee osteoarthritis was analyzed, adjusting for various covariates.

Results

Prevalence of knee osteoarthritis in Koreans aged ≥50 years was 36.6%, and higher in women (men: 24.9%, women: 45.4%). Prevalence of knee osteoarthritis in participants with hypertension was significantly higher than those without hypertension (fully adjusted odds ratio (OR) 1.26; 95% confidence interval (CI) 1.08–1.48). Knee osteoarthritis prevalence was also higher in participants with impaired fasting glucose or diabetes than those without (age, sex adjusted OR 1.19; 95% CI 1.00–1.41). Also, OR values increased statistically significantly with FRS as a continuous variable (fully adjusted OR 1.007; 95% CI 1.00–1.01).

Conclusions

Prevalence of knee osteoarthritis was associated with hypertension and diabetes, which are major cardiovascular risk factors, and the FRS. Further studies on FRS pertaining to its relationship with osteoarthritis are warranted.

Comparison of basic physical fitness, aerobic capacity, and isokinetic strength between national and international level high school freestyle swimmers

[Purpose] This study aimed to compare basic physical fitness, aerobic capacity, and isokinetic strength between international and national level freestyle high school student swimmers. [Subjects and Methods] A total of 28 participants (14 international level swimmers and 14 national level freestyle high school student swimmers) with no known pathology were included. We used a cross-sectional study to examine three variables: basic physical fitness, aerobic capacity, and isokinetic strength. [Results] The mean values of these variables in the international level swimmers were higher than those in the national level swimmers. Swimmers are generally physically fit with a good competition record. [Conclusion] An appropriate training program, which considers specific individual characteristics is likely to have a positive impact on the improvement of total physical fitness, and subsequently, on the performance of the freestyle high school swimmer.

Comparison of joint angles and electromyographic activity of the lower extremities during standing with wearing standard and revised high-heeled shoes: A pilot study

Revised high-heeled shoes (HHSs) were designed to improve the shortcomings of standard HHSs. This study was conducted to compare revised and standard HHSs with regard to joint angles and electromyographic (EMG) activity of the lower extremities during standing. The participants were five healthy young women. Data regarding joint angles and EMG activity of the lower extremities were obtained under three conditions: barefoot, when wearing revised HHSs, and when wearing standard HHSs. Lower extremity joint angles in the three dimensional plane were confirmed using a VICON motion capture system. EMG activity of the lower extremities was measured using active bipolar surface EMG. Kruskal-Wallis one-way analysis of variance by rank applied to analyze differences during three standing conditions. Compared with the barefoot condition, the standard HHSs condition was more different than the revised HHSs condition with regard to lower extremity joint angles during standing. EMG activity of the lower extremities was different for the revised HHSs condition, but the differences among the three conditions were not significant. Wearing revised HHSs may positively impact joint angles and EMG activity of the lower extremities by improving body alignment while standing.

The influence of revised high-heeled shoes on foot pressure and center of pressure during standing in young women

[Purpose] Revised high-heeled shoes were developed to minimize foot deformities by reducing excessive load on the forefoot during walking or standing in adult females, who frequently wear standard high-heeled shoes. Specifically, this study aimed to investigate the effects of revised high-heeled shoes on foot pressure distribution and center of pressure distance during standing in adult females. [Subjects and Methods] Twelve healthy adult females were recruited to participate in this study. Foot pressures were obtained under 3 conditions: barefoot, in revised high-heeled shoes, and in standard 7-cm high-heeled shoes. Foot pressure was measured using the Tekscan HR mat scan system. One-way repeated analysis of variance was used to compare the foot pressure distribution and center of pressure distance under these 3 conditions. [Results] The center of pressure distance between the two lower limbs and the fore-rear distribution of foot pressure were significantly different for the 3 conditions. [Conclusion] Our findings support the premise that wearing revised high-heeled shoes seems to provide enhanced physiologic standing posture compared to wearing standard high-heeled shoes.

An efficacy study on improving balance and gait in subacute stroke patients by balance training with additional motor imagery: a pilot study

[Purpose] The few studies conducted on subacute stroke patients have focused only on gait function improvement. This study therefore aimed to confirm the effect of balance training with additional motor imagery on balance and gait improvement in subacute stroke patients. [Subjects and Methods] Participants were divided into an experimental or control group. The experimental group received balance training for 20 minutes/day with mental imagery for 10 minutes/day, three days/week, for four weeks. The control group received only balance training for 30 minutes. Before and after the 12 sessions, balance and gait ability were assessed by the researcher and a physical therapist. [Results] After completion of the 4-week intervention, Berg Balance Scale, Timed Up and Go test, Functional Reach Test, and Four Square Step test scores significantly increased in the experimental group. In the control group, Berg Balance Scale and Functional Reach Test scores significantly improved. Changes in the Timed Up and Go test, Functional Reach Test, and Four Square Step Test scores after intervention were significantly higher in the experimental than in the control group. [Conclusion] Specific balance training with additional motor imagery may result in better rehabilitation outcomes of gait and balance ability than balance training alone.

Association between Hypertension and the Prevalence of Low Back Pain and Osteoarthritis in Koreans: A Cross-Sectional Study

BACKGROUND

Hypertension and musculoskeletal disorders are highly prevalent in adult populations. The objective of this study was to investigate the association between hypertension and prevalence of low back pain (LBP) and osteoarthritis in Koreans.

METHODS

A total 17,128 participants (age ≥20 years) who answered low back pain and osteoarthritis items in the 4th Korean National Health and Nutrition Examination Survey (2007-2009) were analyzed. Odds ratios were calculated using logistic regression and were adjusted for age, sex, income level, education, occupation, BMI, smoking status, alcohol consumption, and physical activity.

RESULTS

Lifetime prevalence of LBP in hypertensive subjects was 34.4%, and that of osteoarthritis 26.2%. LBP prevalence was significantly lower in hypertensives (fully adjusted OR 0.79; 95% CI 0.70-0.90), and both LBP and osteoarthritis prevalence was significantly lower in participants with systolic blood pressure ≥140mmHg than those with <120mmHg (fully adjusted OR 0.81; 95% CI 0.70-0.94, and 0.81; 95% CI 0.68-0.96, respectively). Prevalence of LBP in subjects with diastolic blood pressure ≥90mmHg was also significantly lower than those with <80mmHg (fully adjusted OR 0.73; 95% CI 0.63-0.85). LBP and osteoarthritis prevalence did not differ by systolic or diastolic blood pressure interval in respondents taking antihypertensive medication. LBP and osteoarthritis prevalence increased with longer hypertension duration (fully adjusted p for trend 0.028, and 0.0008, respectively).

CONCLUSIONS

Hypertension showed an inverse relationship with LBP and osteoarthritis prevalence, which may be ascribed to hypertension-associated hypalgesia, and antihypertensive medication intake and longer hypertension duration attenuated this association.

Aerobic training during hemodialysis improves body composition, muscle function, physical performance, and quality of life in chronic kidney disease patients

[Purpose] We assessed the influences of individualized aerobic training on body composition, knee joint muscle function, physical performance, and quality of life in chronic kidney disease patients. [Subjects] Ten chronic kidney disease patients undergoing dialysis. [Methods] Overall physical function and quality of life before and after 12 weeks of aerobic training were evaluated by body composition, the six-minute walk test, cardiopulmonary exercise tests, and Short Form 36-item questionnaire. [Results] The six-minute walk test distance increased significantly after 12 weeks aerobic training. Resting metabolic rate, lactate threshold, maximum oxygen uptake, and quality of life tended to increase after training. Post-training weight, muscle mass, body fat mass, fat percentage, body mass index, and peak torque of right and left knee extension and flexion did not change significantly. [Conclusion] Intra-dialytic training can a safe approach to maintain or improve physical performance and quality of life of chronic kidney disease patients undergoing hemodialysis without adverse events or negative cardiovascular responses. Aerobic training may prevent a decline in body composition and knee joint muscle function due to inactivity in chronic kidney disease patients. Clinically, aerobic training may initially be adapted to maintain overall physical function or improve quality of life in chronic kidney disease patients undergoing hemodialysis.

Effect of space balance 3D training using visual feedback on balance and mobility in acute stroke patients

[Purpose] The purpose of the study was to determine the effects of balance training with Space Balance 3D, which is a computerized measurement and visual feedback balance assessment system, on balance and mobility in acute stroke patients. [Subjects and Methods] This was a randomized controlled trial in which 52 subjects were assigned randomly into either an experimental group or a control group. The experimental group, which contained 26 subjects, received balance training with a Space Balance 3D exercise program and conventional physical therapy interventions 5 times per week during 3 weeks. Outcome measures were examined before and after the 3-week interventions using the Berg Balance Scale (BBS), Timed Up and Go (TUG) test, and Postural Assessment Scale for Stroke Patients (PASS). The data were analyzed by a two-way repeated measures ANOVA using SPSS 19.0. [Results] The results revealed a nonsignificant interaction effect between group and time period for both groups before and after the interventions in the BBS score, TUG score, and PASS score. In addition, the experimental group showed more improvement than the control group in the BBS, TUG and PASS scores, but the differences were not significant. In the comparisons within the groups by time, both groups showed significant improvement in BBS, TUG, and PASS scores. [Conclusion] The Space Balance 3D training with conventional physical therapy intervention is recommended for improvement of balance and mobility in acute stroke patients.

Effect of revised high-heeled shoes on foot pressure and static balance during standing

[Purpose] The purpose of this study was to investigate the effects of revised high-heeled shoes on the foot pressure ratio and static balance during standing. [Subjects and Methods] A single-subject design was used, 15 healthy women wearing revised high-heeled shoes and general high-heeled shoes in a random order. The foot pressure ratio and static balance scores during standing were measured using a SpaceBalance 3D system. [Results] Forefoot and rearfoot pressures were significantly different between the 2 types of high-heeled shoes. Under the 3 conditions tested, the static balance score was higher for the revised high-heeled shoes than for the general high-heeled shoes, but this difference was not statistically significant. [Conclusion] Revised high-heeled shoes are preferable to general high-heeled shoes, as they result in normalization of normalized foot pressure and a positive effect on static balance.

Analgesic effects of transcutaneous electrical nerve stimulation and interferential current on experimental ischemic pain models: frequencies of 50 hz and 100 hz

[Purpose] This study compared the analgesic effects of transcutaneous electrical nerve stimulation (TENS) and interferential currents (IFC) on induced ischemic pain in healthy volunteers. [Subjects] The subjects were 36 volunteers (18 male, 18 female) without known pathology that could cause pain. Their mean age was 24.5±2.2 years. [Methods] A single-blind and parallel-group method was used. Subjects were randomly allocated to receive each 50 Hz TENS, 50 Hz IFC, 100 Hz TENS, and 100 Hz IFC. This study experimentally induced ischemic pain in otherwise pain-free subjects using a modified version of the submaximal effort tourniquet technique. Subjects completed twelve cycles of the ischemic-induced pain test. The primary outcome measure was the change in self-reported of pain intensity during one of four possible treatments. [Results] There were significant effects for Time, which were attributed to a significant reduction in pain intensity for all groups. There were no significant effects for groups or group-time interaction. The 50 Hz IFC treatment was more comfortable than the other treatments in the present study, and it is likely to be better accepted and tolerated by patients. [Conclusion] We conclude that there were no differences in the analgesic effects of the four treatments under the present experimental conditions. The 50 Hz IFC treatment is more comfortable than the other treatments.

Effects of Robot-assisted Gait Training Combined with Functional Electrical Stimulation on Recovery of Locomotor Mobility in Chronic Stroke Patients: A Randomized Controlled Trial

[Purpose] The purpose of the present study was to investigate the effects of robot-assisted gait training combined with functional electrical stimulation on locomotor recovery in patients with chronic stroke. [Subjects] The 20 subjects were randomly assigned into either an experimental group (n = 10) that received a combination of robot-assisted gait training and functional electrical stimulation on the ankle dorsiflexor of the affected side or a control group (n = 10) that received robot-assisted gait training only. [Methods] Both groups received the respective therapies for 30 min/day, 3 days/week for 5 weeks. The outcome was measured using the Modified Motor Assessment Scale (MMAS), Timed Up-and-Go Test (TUG), Berg Balance Scale (BBS), and gait parameters through gait analysis (Vicon 370 motion analysis system, Oxford Metrics Ltd., Oxford, UK). All the variables were measured before and after training. [Results] Step length and maximal knee extension were significantly greater than those before training in the experimental group only. Maximal Knee flexion showed a significant difference between the experimental and control groups. The MMAS, BBS, and TUG scores improved significantly after training compared with before training in both groups. [Conclusion] We suggest that the combination of robot-assisted gait training and functional electrical stimulation encourages patients to actively participate in training because it facilitates locomotor recovery without the risk of adverse effects.

Doxorubicin loaded pH-sensitive micelle targeting acidic extracellular pH of human ovarian A2780 tumor in mice

The purpose of this study was to examine the efficacy of a chemotherapeutic drug, doxorubicin (DOX), loaded in pH-sensitive micelles poly(l-histidine) (M(n):5K)-b-PEG (M(n):5K) micelles. The micelles were designed to target the acidic extracellular pH of solid tumors. Studies of pH-dependent cytotoxicity, growth rate of the tumor, pharmacokinetics and biodistribution were conducted. In vitro DOX uptake upon A2780 cells by incubating the cells in a pH 6.8 complete medium at a concentration of 20 microg DOX/ml in the micelle formulation was more than five times that of pH 7.4 condition for initial 20 min. In vivo pharmacokinetic data showed that AUC (area under concentration curve) and half life time (t(1/2)) (plasma half life) of DOX in the pH sensitive micelles increased about 5.8- and 5.2-fold of free DOX in phosphate buffered saline (PBS), respectively. It appeared that DOX in the pH-sensitive micelles preferentially accumulated in the tumor site. The distributions at 12 h post injection in other organs including liver, kidney, spleen, lung and heart were not significantly different from those of DOX in PBS at a 6 mg DOX/kg dose. The in vivo test of anti-tumor activity was performed with human ovarian carcinoma A2780 which was subcutaneously xenografted in female nu/nu athymic mice. The pH-sensitive micelle formulation significantly retarded tumor growth rate without serious body weight loss. The triggered drug release by the reduced tumor pH is believed to be a major mechanism of the observed efficacy after passive accumulation of the micelles by EPR effect. This may have resulted in a local high dose of drug in the tested solid tumor.

Bioactive polymers for biohybrid artificial pancreas

To address the solution for some of the obstacles, such as low insulin secretion, limited lifespan and aggregation of transplanted islets, encountered in developing a biohybrid artificial pancreas (BAP), polymeric materials including a reversible polymeric extracellular matrix (ECM), crystallized glucagon-like peptide-1, and oxygen carrying polymers, were prepared and their potential utilities in designing a compact and rechargeable BAP were investigated. For a synthetic, reversible ECM, high molecular weight N-isopropylacrylamide copolymer with a small amount of acrylic acid (2 mole%) was synthesized by conventional radical polymerization in benzene, and its aqueous solution above a critical polymer concentration displayed a sol-gel transition temperature near physiological temperature (33-35 degrees C) without noticeable hysteresis. The physicochemical properties of the gel with islet compatibility proved that the synthetic ECM is an appropriate matrix which can make a BAP rechargeable. Glucagon-like peptide-1 (GLP-1, 7-37) is known to have a strong stimulatory effect on insulin secretion, particularly at high glucose concentrations. When zinc-crystallized GLP-1 was entrapped along with islets in a hollow fiber macrocapsule device, insulin secretion was enhanced at a high glucose concentration (300 mg/dl) with a >85% increase in insulin secretion after an induction period. The cross-linked hemoglobin with difunctional PEO (Hb-C) was prepared to increase the high molecular weight of Hb. This prevents diffusional loss when enclosed in an immunoprotecting membrane. The Hb-C, entrapped in microcapsules, enhanced insulin secretion and improved the viability of microencapsulated islets by promoting oxygen supply to islets. The introduction of the synthetic ECM, crystallized GLP-1, and Hb-C into a BAP may provide a basis for designing a compact and rechargeable BAP (macrocapsule).

PDMS-based polyurethanes with MPEG grafts: mechanical properties, bacterial repellency, and release behavior of rifampicin

PDMS-based polyurethanes (PUs) grafted with monomethoxy poly(ethylene glycol) (MPEG) were synthesized to develop a coating material for urinary catheters with a silicone surface for minimizing urinary tract infections. MPEG was grafted on PDMS-based PUs by two methods depending on the PU synthetic routes: esterification and allophanate reactions. It was confirmed from mechanical characterization that an increase of the hard segment amount enhanced the ultimate strength and Young's modulus, while reducing elongation at the end-points. The incorporation of MPEG in PDMS-based PUs induced a decrease in tensile strength and Young's modulus, and increased elongation at the break point due to its high flexibility. When hydrated in distilled water, mechanical properties of all PUs synthesized in this study deteriorated due to water absorption. It was evident from the bacterial adhesion test that PDMS-based PUs showed moderate resistance to adhesion of E. coli on their surfaces compared to Pellethane, while the incorporation of MPEG significantly enhanced repellency to bacteria, including E. coli and S. epidermidis. We also studied the release behavior of an antibiotic drug, rifampicin, from the polymeric devices fabricated by solvent evaporation. Although rifampicin is hydrophilic and soluble in pH 7.4 phosphate buffer, it showed a sustained release over 45 days from PDMS-based PUs with MPEG that were grafted on ethylene glycol residues by allophanate reaction. This release characteristic was predominantly influenced by a hydrogen bond interaction between the polymers and rifampicin, which was confirmed through an ATR-IR study. This may imply that the specific interaction is responsible for the delayed release. Considering the mechanical properties, morphologies of drug-incorporated polymeric matrices, and drug release behaviors, PDMS-based PU with MPEG that were grafted on ethylene glycol (a chain extender) residues by allophanate reaction showed better material properties for uretharal catheter coating pusposes in order to minimize urinary tract infections.

Interaction of sulfonylurea-conjugated polymer with insulinoma cell line of MIN6 and its effect on insulin secretion

A carboxylated derivative of sulfonylurea (SU), an insulinotropic agent, was synthesized and grafted onto a water-soluble polymer as a biospecific and stimulating polymer for insulin secretion. To evaluate the effect of the SU-conjugated polymer on insulin secretion, its solution in dimethyl sulfoxide was added to the culture of insulinoma cell line of MIN6 cells to make 10 nM of SU units in the medium and incubated for 3 h at 37 degrees C. The culture medium was conditioned with glucose concentration of 3.3 or 25 mM. To verify the specific interaction between the SU (K+ channel closer)-conjugated polymer and MIN6 cells, the cells were pretreated with diazoxide, an agonist of adenosine triphosphate-sensitive K+ channel (K+ channel opener), before adding the SU-conjugated polymer to the cell culture medium. This treatment suppressed the action of SUs on MIN6 cells. Fluorescence-labeled polymer with rodamine-B isothiocyanate was used to visualize the interactions, and we found that the labeled polymer strongly absorbed to MIN6 cells, probably owing to its specific interaction mediated by SU receptors on the cell membrane. The fluorescence intensity on the cells significantly increased with an increase in incubation time and polymer concentration. A confocal laser microscopic study further confirmed this interaction. The results from this study provided evidence that SU-conjugated copolymer stimulates insulin secretion by specific interactions of SU moieties in the polymer with MIN6 cells.

The effect of zinc-crystallized glucagon-like peptide-1 on insulin secretion of macroencapsulated pancreatic islets

This research investigates the use of an insulinotropic factor, glucagon-like peptide-1 (GLP-1), to enhance insulin secretion from islets within a macrocapsule. A zinc-crystallized form of GLP-1 was added to the macrocapsule device to have a longer and more controlled release of the bioactive monomer GLP-1. The type of macrocapsule device used for this study consisted of a hollow fiber (MWCO 100,000 and 1 mm inner diameter) containing rat islets and GLP-1 crystals within a poly(N-isopropylacrylamide-co-acrylic acid) (2 mol% acrylic acid) matrix. When incubating the system in media with a high glucose concentration (300 mg/dL), insulin secretion was enhanced with a >85% increase after an induction period. When the same type of system was used in a dynamic perfusion experiment, similar results were obtained. GLP-1 crystals can be an effective form to be entrapped in a bioartificial pancreas to enhance insulin secretion function, especially at high glucose concentrations.

Self-assembled hydrogel nanoparticles from curdlan derivatives: characterization, anti-cancer drug release and interaction with a hepatoma cell line (HepG2)

Self-assembled hydrogel nanoparticles were synthesized from carboxymethylated (CM)-curdlan, substituted with a sulfonylurea (SU) as a hydrophobic moiety for self-assembly. The degree of SU substitution was 2.4, 5.6, or 7.2 SU groups per hundred anhydroglucose units of curdlan. The physicochemical properties of the self-assembled hydrogel nanoparticles (DS 2.4, DS 5.6, and DS 7.2) in aqueous media were characterized by dynamic light scattering, transmission electron microscopy, and fluorescence spectroscopy. The mean diameter of all samples was less than 300 nm with a unimodal size distribution. The critical aggregation concentrations (CAC) of self-assembled hydrogel nanoparticles in distilled water were 4.2 x 10(-2), 3.1 x 10(-2) and 1.9 x 10(-2) mg/ml for DS 2.4, 5.6 and 7.2, respectively. The loading and release of all-trans retinoic acid (ATRA) was studied. The ATRA loading efficiencies and loading contents of CM-curdlan/SU nanoparticles increased as the degree of SU substitution increased. The ATRA release rate was controlled by the degree of substitution and drug-loading. For specific interaction with a hepatic carcinoma cell line (HepG2), CM-curdlan was additionally conjugated with lactobionic acid (LBA; galactose moiety) (5.5 LBA molecules per hundred glucose units). HepG2 was strongly luminated by ligand-receptor interactions with fluorescence-labeled LBA/CM-curdlan/SU hydrogel nanoparticles. The luminescence was not observed for other control cases. It is concluded that LBA/CM-curdlan/SU hydrogel nanoparticles are a useful drug carrier for the treatment of liver cancer, because of the potential immunological enhancement activities of CM-curdlan in the body, the ligand-receptor mediated specific interactions, and the controlled release of the anti-cancer drug.

Cell transplantation for endocrine disorders

Current hormonal replacement therapy for endocrine disorders cannot, unfortunately, reproduce the complex metabolic interactions of hormones. The organ or cell transplantation would be a more physiological approach to the treatment of endocrine disorders. For decades, remarkable progress in organ or cell transplantation in endocrine disorders has been made, especially in recent years. But there are many limitations in the widespread application of allotransplantation because of rejection. Various methods of immunomanipulations designed to overcome rejection have been proposed, which include immunosuppression, immunomodulation and immunoisolation. The transplantation of immunoisolated cells and some clinical results of the transplants were reviewed. Also a perspective for future directions on endocrine cell transplantation was provided in this review. Human islet cell transplantation for the cure of diabetes was emphasized in this chapter and other cell transplantation for endocrine disorders was also discussed briefly, including parathyroid tissue transplantation, bioartificial thyroid transplantation and adrenal cell transplantation.

Thermoreversible copolymer gels for extracellular matrix

To improve the properties of a reversible synthetic extracellular matrix based on a thermally reversible polymer, copolymers of N-isopropylacrylamide and acrylic acid were prepared in benzene with varying contents of acrylic acid (0 to 3%) and the thermal properties were evaluated. The poly(N-isopropylacrylamide) and copolymers made with acrylic acid had molecular weights from 0.8 to 1.7 x10(6) D. Differential scanning calorimetry (DSC) showed the high-molecular-weight acrylic acid copolymers had similar onset temperatures to the homopolymers, but the peak width was considerably increased with increasing acrylic acid content. DSC and cloud point measurements showed that polymers with 0 to 3% acrylic acid exhibit a lower critical solution temperature (LCST) transition between 30 degrees and 37 degrees C. In swelling studies, the homopolymer showed significant syneresis at temperatures above 31 degrees C. Copolymers with 1 and 1.5% showed syneresis beginning at 32 degrees and 37 degrees C, respectively. At 37 degrees C the copolymers with 1.5-3% acrylic acid showed little or no syneresis. Due to the high water content and a transition near physiologic conditions (below 37 degrees C), the polymers with 1.5-2.0% acrylic acid exhibited properties that would be useful in the development of a refillable synthetic extracellular matrix. Such a matrix could be applied to several cell types, including islets of Langerhans, for a biohybrid artificial pancreas.

Anti-oxidative neuroprotection by estrogens in mouse cortical cultures

Estrogen replacement therapy in postmenopausal women may reduce the risk of Alzheimer's disease, possibly by ameliorating neuronal degeneration. In the present study, we examined the neuroprotective spectrum of estrogen against excitotoxicity, oxidative stress, and serum-deprivation-induced apoptosis of neurons in mouse cortical cultures. 17beta-estradiol as well as 17alpha-estradiol and estrone attenuated oxidative neuronal death induced by 24 hr exposure to 100 microM FeCl2, excitotoxic neuronal death induced by 24 hr of exposure to 30 microM N-methyl-D-aspartate (NMDA) and serum-deprivation induced neuronal apoptosis. Furthermore, estradiol attenuated neuronal death induced by Abeta25-35. However, all these neuroprotective effects were mediated by the anti-oxidative action of estrogens. When oxidative stress was blocked by an antioxidant trolox, estrogens did not show any additional protection. Addition of a specific estrogen receptor antagonist ICI182,780 did not reverse the protection offered by estrogens. These findings suggest that high concentrations of estrogen protect against various neuronal injuries mainly by its anti-oxidative effects as previously shown by Behl et al. Our results do not support the view that classical estrogen receptors mediate neuroprotection.

In situ gelation of PEG-PLGA-PEG triblock copolymer aqueous solutions and degradation thereof

Aqueous solutions of poly(ethylene glycol-b-[DL-lactic acid-co-glycolic acid]-b-ethylene glycol) (PEG-PLGA-PEG) triblock copolymers form a free-flowing sol at room temperature and become a gel at body temperature. In this study, in situ gel formation was investigated in rats. Upon subcutaneous injection of 33 wt % aqueous solutions of PEG-PLGA-PEG triblock copolymer into rats, transparent gels were observed. The gel showed good mechanical strength and the integrity of gels persisted longer than 1 month. The gel underwent degradation by hydrolysis and turned opaque. Degradation study showed preferential mass loss of PEG-rich segment from the in situ formed gel. Number average molecular weight determined by gel permeation chromatography decreased from 3300 to 1900 and 30% mass loss was observed over 1 month.

A glucose oxidase electrode based on electropolymerized conducting polymer with polyanion-enzyme conjugated dopant

An enzyme immobilization method has been developed by electropolymerization chemistry of conducting polymer which results in a more effective and reproducible enzyme electrode. As a model system, in this study, glucose oxidase (GOD) was conjugated with a polyanion, poly(2-acrylamido-2-methylpropane sulfonic acid), via a poly(ethylene oxide) spacer to improve the efficiency of enzyme immobilization into a conducting polymer. GOD was successfully conjugated with a high conjugation yield of more than 90%, and its bioactivity was preserved. The resulting polyanion-GOD conjugate was used as a dopant for the electrochemical polymerization of pyrrole. Polypyrrole was effectively deposited on a Pt wire working electrode with the polyanion-GOD conjugate. The enzyme electrode responded to glucose concentrations of up to 20 mM with a sensitivity of 40 nA/mM at an applied potential of 0.4 V within a response time of 30 s. Although the response signal decreased at the low applied potential of 0.3 V, the enzyme electrode showed sensitive response signals of about 16 nA/mM up to 20 mM in glucose concentration. Under the deoxygenated condition, reduced but clear response current signal was obtained. The results show that the current signal response of the enzyme electrode to glucose concentration may be produced by mixed mechanisms.

Biodegradable amphiphilic multiblock copolymers and their implications for biomedical applications

Alternating multiblock copolymers composed of short blocks of poly(ethylene oxide) (PEO) and poly(epsilon-caprolactone) (PCL) or poly(L-lactic acid) (PLLA) were synthesized by a coupling reaction. The block copolymers of relatively high molecular weights (M(n)20,000) formed a physically crosslinked thermoplastic network, while low molecular weight polymers were water-soluble. The block copolymers demonstrated solubility in a variety of solvents including acetone, tetrahydrofuran, methylene chloride, dioxane, water/acetone mixtures, and water/ethanol mixtures. The degree of swelling, optical transparency, and mechanical property of the films, prepared by a solvent casting method, were affected by the nature of the hydrophobic block used, polymer composition, temperature, and thermal history. The crystalline melting temperatures of PCL and PLLA in the block copolymers were significantly lowered due to the chemical structure of difunctional PCL and PLLA, and partial phase mixing with PEO segments. The properties of the block copolymers may be useful for biomedical applications as well as controlled drug release formulations. When PEO/PLLA multiblock copolymers were applied as a wound healing material loaded with basic fibroblast growth factor (bFGF), the feasibility study showed improved wound healing when compared to controls of no treatment and the same wound covering without bFGF, indicating that a certain degree of the bioactivity of bFGF is preserved.

Drug release from biodegradable injectable thermosensitive hydrogel of PEG-PLGA-PEG triblock copolymers

An aqueous solution of newly developed low-molecular-weight PEG-PLGA-PEG triblock copolymers with a specific composition is a free flowing sol at room temperature but becomes a gel at body temperature. Two model drugs, ketoprofen and spironolatone, which have different hydrophobicities, were released from the PEG-PLGA-PEG triblock copolymer hydrogel formed in situ by injecting the solutions into a 37 degrees C aqueous environment. Ketoprofen (a model hydrophilic drug) was released over 2 weeks with a first-order release profile, while spironolactone (a model hydrophobic drug) was released over 2 months with an S-shaped release profile. The release profiles were simulated by models considering degradation and diffusion, and were better described by a model assuming a core-shell structure of the gel.