Growth/differentiation factor 15 causes TGFß-activated kinase 1-dependent muscle atrophy in pulmonary arterial hypertension.

INTRODUCTION: Skeletal muscle dysfunction is a clinically important complication of pulmonary arterial hypertension (PAH). Growth/differentiation factor 15 (GDF-15), a prognostic marker in PAH, has been associated with muscle loss in other conditions. We aimed to define the associations of GDF-15 and muscle wasting in PAH, to assess its utility as a biomarker of muscle loss and to investigate its downstream signalling pathway as a therapeutic target. METHODS: GDF-15 levels and measures of muscle size and strength were analysed in the monocrotaline (MCT) rat, Sugen/hypoxia mouse and in 30 patients with PAH. In C2C12 myotubes the downstream targets of GDF-15 were identified. The pathway elucidated was then antagonised in vivo. RESULTS: Circulating GDF-15 levels correlated with tibialis anterior (TA) muscle fibre diameter in the MCT rat (Pearson r=-0.61, p=0.003). In patients with PAH, plasma GDF-15 levels of <564 pg/L predicted those with preserved muscle strength with a sensitivity and specificity of ≥80%. In vitro GDF-15 stimulated an increase in phosphorylation of TGFß-activated kinase 1 (TAK1). Antagonising TAK1, with 5(Z)-7-oxozeaenol, in vitro and in vivo led to an increase in fibre diameter and a reduction in mRNA expression of atrogin-1 in both C2C12 cells and in the TA of animals who continued to grow. Circulating GDF-15 levels were also reduced in those animals which responded to treatment. CONCLUSIONS: Circulating GDF-15 is a biomarker of muscle loss in PAH that is responsive to treatment. TAK1 inhibition shows promise as a method by which muscle atrophy may be directly prevented in PAH. TRIAL REGISTRATION NUMBER: NCT01847716; Results.

Men in Occupational Therapy: Issues, Factors, and Perceptions.

OBJECTIVE: Relatively few men are occupational therapy practitioners in the United States. Little research has examined issues germane to men working in the profession. The objective of this study was to investigate perceptions, issues, and factors surrounding male occupational therapy practitioners. METHOD: A survey link was emailed to 9,467 licensed occupational therapy practitioners in Ohio; 699 participants responded, yielding a response rate of 7.66%. RESULTS: Male and female participants provided both similar and significantly different responses to the survey questions. Differences generally involved responses to questions on personal finances and client education. Themes were identified from the open-ended questions regarding gender stereotypes. CONCLUSION: Although male and female practitioners differed in opinion on several issues and perceptions related to the profession, in general they were happy with their career choice. Specifically, participants expressed that they enjoyed their job, contributed to society, and had a sense of job security, regardless of gender.

Efficiency of unimanual and bimanual reach in persons with and without stroke.

BACKGROUND: Deficiencies in motor control are one of the largest challenges faced by stroke survivors in regaining their independence after stroke. OBJECTIVE: This study investigated movement efficiency in people with and without stroke during both unimanual and bimanual upper extremity reaching tasks. METHOD: Twenty-five participants (12 with stroke and 13 age-matched controls) between the ages of 36-69 years randomly experienced testing conditions involving reaching forward unimanually and bimanually at a preferred speed in a single session. Kinematic and kinetic outcomes included movement time, movement units, peak velocity, and percentage of movement time to peak velocity. RESULTS: In stroke participants, the unimpaired limb accommodated its movements to that of the less efficient paretic limb during bimanual conditions indicating yoked movement efficiency because its performance was more efficient (P < 0.05) in unilateral trials, whereas the impaired limb's performance did not differ between the unimanual and bimanual conditions (P>0.05). Control subjects elicited greater movement efficiency than participants with stroke. CONCLUSION: Motor efficiency of the unimpaired upper extremity may be adversely influenced when yoked with the impaired limb during symmetrical simple movements in persons with stroke. As such, motor efficiency is not exclusively limited to the impaired side, the effects of which may be task dependent.

Degree of Preference and Its Influence on Motor Control When Reaching for Most Preferred, Neutrally Preferred, and Least Preferred Candy.

The objective of this study was to determine whether reaching for objects with varying levels of preference associated with them elicited influenced motor control in a reaching task. Forty healthy adults were asked to reach for seven different types of candy, which they ranked by personal preference from being the most preferred to the least preferred. In this repeated measures design, data were analyzed on 39 participants who tended to demonstrate greater movement efficiency in movement time and movement units when reaching for candy in which they associated with greater preference (p < .0 167). Although no differences were found between conditions with peak velocity and percentage of movement time to peak velocity (p > .0167), these dependent variables appeared to trend in the direction of similar movement efficiency. Therapists can use this knowledge to help guide clinical reasoning when designing treatment plans and approaches. Future research is needed to further examine intensity along the continuum of preference and its implications for occupational therapy practice.

Occupational Embeddedness, Perceived Risk, and the Quality of Reach Motion in Females Aged 7 to 9 Years.

The perceived meaning ascribed to objects can influence the motor control efficiency in adults when reaching. However, little is known whether the same phenomenon occurs in pediatric females. Twenty-seven girls aged 7 to 9 years recruited from Girl Scout Brownie troupes and afterschool programs were asked to reach for plastic and porcelain teacups in the context of a "tea party" scenario. No differences were found in most of the motion capture variables (p > .05), and effect sizes were small. It is likely that the perceived meaning of the tea party was so robust that it overwhelmed any perceived differences inherent between the two conditions. Future research is needed to clarify the age at which children can qualitatively discern meaningful differences between objects.

Long-handled shoehorn length, body mass index, and hip range of motion in healthy female adults.

We examined the effect that long-handled shoehorn (LHSH) length and body mass index (BMI) have on hip range of motion (ROM) in female adults. Thirty-eight female participants were asked to don a shoe using 18-, 24-, and 30-in. LHSHs. Significant differences in hip flexion were found between the 18- and the 24-in. shoehorns and between the 18- and the 30-in. shoehorns. A significant positive relationship was found between BMI and internal rotation for each of the LHSHs. The results suggest that healthy women with low BMLs using a 24- or 30-in. LHSH have the greatest chance of not violating hip flexion or hip internal rotation ROM precautions. Implications suggest that therapists consider individual BMI and available hip ROM before prescribing an LHSH. A follow-up study is needed involving populations who would likely benefit from using LHSHs.

Grasping naturally versus grasping with a reacher in people without disability: motor control and muscle activation differences.

OBJECTIVE: We investigated motor control and muscle activation when reaching for and grasping objects with a reacher compared with the unaided hand. METHOD: In a repeated-measures counterbalanced design, 41 healthy participants with no previous experience using a reacher were randomly assigned to a sequence of four conditions. Movements of the wrist and fingers were recorded using a three-dimensional Qualisys camera system for assessing reach and grasp. Muscle activations from finger and arm flexors and extensors were recorded by surface electromyography. RESULTS: Participants exhibited a smaller grasp aperture, longer reaching time, and more muscle activity when they used a reacher. CONCLUSION: Efficient motor control, which requires both time and practice, is needed to successfully use a reacher. Clients presented with reachers without sufficient time to develop motor skills unique to reacher use may be more likely to abandon this assistive device and fail to benefit from its function.

Knowledge of results and learning to tell the time in an adult male with an intellectual disability: a single-subject research design.

The present study investigated whether knowledge of results, in the form of visual and audible feedback, would increase the accuracy of time-telling in an individual with an intellectual disability. A 19-year-old male with mild intellectual disability participated in this A1-B1-A2-B2 single-subject study design. The task involved correctly identifying the time given on a computer. Data, based on the Wilcoxon signed-rank test, showed that the participant demonstrated a greater number of correct responses during the intervention phases. Incorporating knowledge of results into a learning strategy for this individual with intellectual disability resulted in an increased ability to accurately identify the correct time on an analogue clock. There is a need to replicate the study design to increase the external validity and generalization of results. The strategies described in the present study may also be useful for occupational therapists who teach individuals with intellectual disability to gain skills in their everyday activities of daily living (ADLs).

Forces involved when sliding a patient up in bed.

BACKGROUND: This study investigated the effects of 3 different types of slide sheets upon hand forces while sliding a patient up in bed. METHODS: The sheets used included the reusable Arjo Maxislide, the McAuley disposable sheet, and a standard cotton sheet. Hand forces were measured from 38 male and female participants as they slid a 'patient' up in bed. A repeated measures ANOVA with 5 levels to the repeated factor (number of sheets and sheet type) was used, along with post-hoc repeated measures contrasts to compare differences between each condition. RESULTS: A significant reduction in required force occurred when using the friction reducing sheets as compared to the cotton sheets when used according to manufacturer recommendations, as well as a reduction in one of the single friction reducing sheet categories compared to the cotton. However, it is important to note that there was still substantial force being placed on the participants. CONCLUSIONS: This study illustrates the importance of using friction reducing slide sheets while engaging in manual patient handling. Future research should investigate the forces involved with other friction reducing materials and methods as well as the possibility of combining said materials and methods.

Semantic priming of motor task performance in young adults: implications for occupational therapy.

OBJECTIVE: To investigate whether the performance of a multisegment motor task is influenced by reading a segment-specific action word. METHOD: Twenty-four participants performed tasks that involved reaching for a bottle, grasping it, lifting and placing it on a shelf, and returning their hand to the starting position. At the initiation of each task, participants read either aloud or silently five randomly provided, task-related words (reach, grasp, lift, place, and return). RESULTS: Reading task-related words significantly affected the reach and lift/place segments in the direction of the hypothesis (p < 0.05) but not the return segments. Grasp times were shorter and grasp velocities were higher when participants read aloud or silently the words grasp and place for the grasp segment (p < 0.05). CONCLUSIONS: The results suggest that in young adults, motor performance may be influenced by precuing or priming the brain with performance-related words. A meaning of a motor performance can be manipulated by contextually relevant language, which can facilitate performance.

Modern agrochemical research: a missed opportunity for drug discovery?

The word "agrochemical" has often taken on a pejorative character in the public mind. Some of the negative tone might have coloured the perception of the industry by pharma, together with views on the chemical nature of agrochemicals that seem to be based on older pesticides that date back to the 1950s and 1960s. In this review, we try to address some of these concerns, draw out the similarities between agrochemical and pharmaceutical research and highlight opportunities for drug discovery that are offered by pesticide-related compounds, particularly with regard to herbicides and compounds with leadlike physical properties.

Personal preference and quality of reach in healthy adult women.

OBJECTIVE: A common practice in occupational therapy is to have clients choose an object that they prefer to be used during treatment. This practice assumes that a preference for chosen items will hold greater meaning and result in higher quality of movement. Little research has been conducted that specifically addresses the effect that preference has on quality of movement. Therefore, the purpose of this study was to contribute to the knowledge by determining whether preference affects quality of movement. METHOD: Forty-three healthy right-hand-dominant adult women between the ages of 18 and 60 years in Northwest Ohio engaged in this study. Each participant rank-ordered 15 magazines from most preferred to least preferred. The participant then reached for her most preferred, neutrally preferred, and least preferred magazines. RESULTS: When participants reached for the neutrally preferred magazines, movement time was significantly slower and movement units were significantly greater (less smooth) than when they reached for a magazine perceived as being the least preferred (p < .017). No differences were found between the three conditions in terms of displacement, peak velocity, or percentage of time to peak velocity, nor between the most preferred and the other two preferences. CONCLUSION: This study has shown that preference may not be an influential factor when performing simple reaches for magazines. Although there was a difference between the neutrally preferred and least preferred conditions, the goal when reaching during the neutrally preferred condition may have been different (i.e., to glean more information from the magazine cover) than when reaching in the least preferred condition (e.g., to reach for and discard the magazine as quickly as possible). These results reflect the complexity involved in the formation of meaning, of which preference is a part. Further exploration of individual preferences as well as personal goal formation and their impact on success in occupations of daily living is needed.

Self-speech-induced facilitation of simple reaching movements in persons with stroke.

OBJECTIVE: Occupational therapists are routinely involved in upper-extremity rehabilitation in persons with stroke. Recently we have reported that self-speech can be used to facilitate simple reach in young and older adults. The purpose of this study is to examine whether self-speech-induced facilitation of simple reach can be translated in persons with stroke. METHOD: Following a counterbalanced repeated-measure design, seven persons with right brain stroke performed reaching and placing a glass on a cabinet shelf under four concurrent speech conditions of vocalizing the word "yeah" with both hemiplegic and nonhemiplegic sides. These four conditions are self-vocalization, external vocalization, imaginary vocalization, and no vocalization. Consistent with our previous study, in this study we also recorded the movement kinematics of angular movement of the upper arm. RESULTS: Reaching velocity was significantly higher under self-vocalization conditions compared to the reaching velocity under no vocalization or other vocalization conditions (p < .05). Motor performance in terms of velocity, nonhemiparetic side was significantly better than hemiparetic side (p < .05). CONCLUSION: The results suggest that self-speech can be used in facilitating movements in patients with stroke. When working with patients with right hemispheric stroke, therapists might explore possibilities of using patient's self-speech to enhance the quality of movement performance.

Perceived risk: effects on reaching and placing performance in persons with cerebrovascular accident.

OBJECTIVE: Developing useful movement with the affected extremity in persons with cerebrovascular accidents (CVAs) is a common occupational therapy goal. The purpose of this study was to examine the effects of perceived risk in an occupational form on upper-extremity movement dynamics in persons who have had CVAs. METHOD: Twenty-eight persons (M = 69.6 years, SD = 15.6 years) with post-CVA participated in the randomly assigned, repeated measures counterbalanced study. In the higher risk condition, participants reached for and grasped a raw egg in an egg carton, transported it, and placed it in a bowl with other raw eggs. The same procedure was completed in the lower risk condition with weight-matched plastic eggs. Participants completed both conditions with their affected and unaffected upper extremities. Dependent variables included total movement time and movement units. RESULTS: The higher risk condition produced statistically significantly longer movement times (p < or = .001), but no difference in movement units (p > .05) compared to the lower risk condition. The affected extremity had significantly longer overall movement times (p < or = .001), but no difference in movement units (p > .05) compared to the unaffected extremity. CONCLUSION: When higher levels of perceived risk are present in an occupational form, slower movements are elicited among persons who have had a CVA. The occupational therapist can grade tasks from relatively lower risk to tasks with relatively higher risk to help patients achieve desired variability in their movement patterns. By doing this, the patient will be better prepared for everyday situations that vary widely in degree of risk.

Frequency of knowledge of results and motor learning in persons with developmental delay.

The purpose of this study was to investigate the effect of high versus low frequency knowledge of results (KR) in a group of 16 individuals with developmental delay and in gender and age-matched average individuals learning a motor skill on a laptop computer. Participants were randomly assigned to either a 100% KR or a 50% KR group. KR was provided during the acquisition phase according to group assignment as participants learned the motor skill, whereas no KR was provided during the retention phase. Results indicated both populations who received 50% KR in the acquisition phase demonstrated better performance in the retention phase than those who received 100% KR. The results of this study suggest that, as has been found in the average population, feedback that is too frequent can interfere with learning and retention of tasks for individuals with developmental disabilities (DD). Limitations involved the small sample size along with the task potentially being artificial in nature. Future research is needed to study further the effects of frequency of KR on skill acquisition, particularly in instrumental activities of daily living in this population.

Jump-landing biomechanics following a 4-week real-time feedback intervention and retention.

BACKGROUND: Poor neuromuscular control can increase the risk of anterior cruciate ligament (ACL) injury. Landing with decreased knee and hip flexion may increase the risk of lower extremity injury. Feedback interventions have demonstrated changes in jump-landing biomechanics. Traditional feedback (TF), provided after task completion, includes critical factors to focus on during jump-landing. Real-time feedback (RTF), provided while completing the task, may be superior for improving jump-landing biomechanics. This investigation evaluated the effect of RTF+TF compared to TF and a control group in changing lower extremity jump-landing biomechanics following a 4-week feedback intervention and a 1-week no feedback retention. METHODS: Participants completed 12 feedback sessions over 4 weeks. At each session, participants performed 6 sets of 6 jumps off a 30 cm box. Participants were provided TF or RTF+TF following each set of jumps. Participants were tested at baseline, immediately following the 4-week intervention and following a 1-week retention. The control group was tested at two time points 4 weeks apart. FINDINGS: Acquisition analysis: RTF+TF and TF groups demonstrated greater change in peak hip flexion angles and peak knee flexion angles compared to the control group following the intervention. TF and RTF+TF groups demonstrated a greater decrease in peak vertical ground reaction force compared to the control group. No significant differences were observed between groups in the retention analysis. INTERPRETATION: This study provides evidence of acquisition of biomechanical changes following a 4-week feedback intervention. Future research should further investigate the retention of biomechanical changes, the optimal length of feedback interventions and transfer of learned biomechanics to similar athletic tasks.

Targeting chemical inputs and optimising HTS for agrochemical discovery.

In vivo high throughput screening (HTS) has been adopted by most of the larger crop protection companies as an important tool for the discovery of new agrochemicals. There has been a paradigm shift in capabilities from screening a few thousand compounds a year to several hundred thousand and the quantity of screening sample required has fallen dramatically. The unifying goal now bringing together screens and inputs is the need to maximise the flow of useful information from HTS and thereby minimise the time taken to discover robust leads and new products. This review examines the positive changes that have occurred towards targeted design and selection of chemical inputs for agrochemical discovery over the last ten years and corresponding developments in HTS assays, data analysis and the logistics of compound storage and dispensing.

Alterations in stride-to-stride variability during walking in individuals with chronic ankle instability.

The aim of this study was to evaluate stride-to-stride variability of the lower extremity during walking in individuals with and without chronic ankle instability (CAI) using a nonlinear analysis. Twenty-five participants with self-reported CAI and 27 healthy control participants volunteered for this study. Participants walked on a motor-driven treadmill for 3 min at their selected speed. Lower extremity kinematics in the sagittal and frontal planes were recorded using a passive retroreflective marker motion capture system. The temporal structure of walking variability was analyzed with sample entropy (SampEn). The CAI group produced lower SampEn values in frontal-plane ankle kinematics compared to the control group (P=.04). No significant group differences were observed for SampEn values of other kinematics (P>.05). Participants with CAI demonstrated less stride-to-stride variability of the frontal plane ankle kinematics compared to healthy controls. Decreased variability of walking patterns demonstrated by participants with CAI indicates that the presence of CAI may be associated with a less adaptable sensorimotor system to environmental changes. The altered sensorimotor function associated with CAI may be targets for clinical interventions, and it is critical to explore how interventions protocols affect sensorimotor system function.