Human activities are fundamentally altering the chemistry of the world's oceans. Ocean acidification (OA) is occurring against a background of warming and an increasing occurrence of disease ...outbreaks, posing a significant threat to marine organisms, communities, and ecosystems. In the current study, (1)H NMR spectroscopy was used to investigate the response of the blue mussel, Mytilus edulis, to a 90-day exposure to reduced seawater pH and increased temperature, followed by a subsequent pathogenic challenge. Analysis of the metabolome revealed significant differences between male and female organisms. Furthermore, males and females are shown to respond differently to environmental stress. While males were significantly affected by reduced seawater pH, increased temperature, and a bacterial challenge, it was only a reduction in seawater pH that impacted females. Despite impacting males and females differently, stressors seem to act via a generalized stress response impacting both energy metabolism and osmotic balance in both sexes. This study therefore has important implications for the interpretation of metabolomic data in mussels, as well as the impact of environmental stress in marine invertebrates in general.
Objective
To explore the feasibility, fidelity, safety, and preliminary outcomes of a physical therapist–administered physical activity (PA) intervention after total knee replacement (TKR).
Methods
...People who had undergone a unilateral TKR and were receiving outpatient physical therapy (PT) were randomized to a control or intervention group. Both groups received standard PT for TKR. The intervention included being provided with a Fitbit Zip, step goals, and 1 phone call a month for 6 months after discharge from PT. Feasibility was measured by rates of recruitment and retention, safety was measured by the frequency of adverse events, and fidelity was measured by adherence to the weekly steps/day goal created by the physical therapist and participant monitoring of steps/day. An Actigraph GT3X measured PA, which was quantified as steps/day and minutes/week of engaging in moderate‐to‐vigorous PA. Our preliminary outcome was the difference in PA 6 months after discharge from PT between the control and intervention groups.
Results
Of the 43 individuals who were enrolled, 53.4% were women, the mean ± SD age was 67.0 ± 7.0 years, and the mean ± SD body mass index was 31.5 ± 5.9 kg/m2. For both the control and intervention groups, the recruitment and retention rates were 64% and 83.7%, respectively, and adherence to the intervention ranged from 45% to 60%. No study‐related adverse events occurred. The patients in the intervention group accumulated a mean 1,798 more steps/day (95% confidence interval 95% CI 240, 3,355) and spent 73.4 more minutes/week (95% CI –14.1, 160.9) engaging in moderate‐to‐vigorous PA at 6 months than those in the control group.
Conclusion
A physical therapist–administered PA intervention is feasible and safe, demonstrates treatment fidelity, and may increase PA after TKR. Future research is needed to establish the effectiveness of the intervention.
Objective:
This study examined concordance between symptom and performance validity among clinically-referred patients undergoing neuropsychological evaluation for Attention-Deficit/Hyperactivity ...Disorder (ADHD).
Method:
Data from 203 patients who completed the WAIS-IV Working Memory Index, the Clinical Assessment of Attention Deficit-Adult (CAT-A), and ≥4 criterion performance validity tests (PVTs) were analyzed.
Results:
Symptom and performance validity were concordant in 76% of cases, with the majority being valid performance. Of the remaining 24% of cases with divergent validity findings, patients were more likely to exhibit symptom invalidity (15%) than performance invalidity (9%). Patients demonstrating symptom invalidity endorsed significantly more ADHD symptoms than those with credible symptom reporting (ηp2 = .06–.15), but comparable working memory test performance, whereas patients with performance invalidity had significantly worse working memory performance than those with valid PVT performance (ηp2 = .18).
Conclusion:
Symptom and performance invalidity represent dissociable constructs in patients undergoing neuropsychological evaluation of ADHD and should be evaluated independently.
To investigate the association of stair climbing difficulty and stair climbing frequency with the risk of all-cause mortality over 13 years in adults with or at high risk for knee OA.
We used data ...from the Osteoarthritis Initiative (OAI), a prospective cohort study of community-dwelling adults with or at high risk for symptomatic knee OA. The exposures were stair climbing difficulty and frequency, assessed at baseline using self-report questionnaires. The outcome was all-cause mortality, assessed from baseline through 13 years of follow-up. Kaplan-Meier survival curves and Cox proportional hazards regression were used to investigate the association between stair climbing exposures and all-cause mortality.
Three hundred seven (6.81%) and 310 (6.84%) participants in the difficulty and frequency samples, respectively, died during 13 years of follow-up. Those who were limited in any capacity in terms of their stair climbing ability had 54% to 84% greater hazard of all-cause mortality, and those who climbed at least 7 flights of stairs per week had 38% lower hazard of all-cause mortality.
Adults with or at high risk for knee OA who report difficulty with climbing stairs or who infrequently use stairs are at greater hazard of all-cause mortality. Stair climbing difficulty and frequency are simple to collect and changes may occur early in OA progression, allowing for early intervention. Brief questions about stair climbing behaviors can serve as a functional vital sign within the clinician's toolbox.
The original version of this paper unfortunately contains three errors in the topology optimization code that was used to generate the examples. Line numbers refer to the code as it appears in ...Appendix D of the original paper.
Objective
Evidence of physical function difficulties, such as difficulty rising from a chair, may limit daily walking for people with knee osteoarthritis (OA). The purpose of this study was to ...identify minimum performance thresholds on clinical tests of physical function predictive to walking ≥6,000 steps/day. This benchmark is known to discriminate people with knee OA who develop functional limitation over time from those who do not.
Methods
Using data from the Osteoarthritis Initiative, we quantified daily walking as average steps/day from an accelerometer (Actigraph GT1M) worn for ≥10 hours/day over 1 week. Physical function was quantified using 3 performance‐based clinical tests: 5 times sit‐to‐stand test, walking speed (tested over 20 meters), and 400‐meter walk test. To identify minimum performance thresholds for daily walking, we calculated physical function values corresponding to high specificity (80–95%) to predict walking ≥6,000 steps/day.
Results
Among 1,925 participants (mean ± SD age 65.1 ± 9.1 years, mean ± SD body mass index 28.4 ± 4.8 kg/m2, and 55% female) with valid accelerometer data, 54.9% walked ≥6,000 steps/day. High specificity thresholds of physical function for walking ≥6,000 steps/day ranged 11.4–14.0 seconds on the 5 times sit‐to‐stand test, 1.13–1.26 meters/second for walking speed, or 315–349 seconds on the 400‐meter walk test.
Conclusion
Not meeting these minimum performance thresholds on clinical tests of physical function may indicate inadequate physical ability to walk ≥6,000 steps/day for people with knee OA. Rehabilitation may be indicated to address underlying impairments limiting physical function.
Objective
Knee cartilage damage is often linked to mechanical overloading. However, cartilage requires mechanical load to remain healthy, suggesting that underloading may be detrimental. This study ...was undertaken to examine knee overloading and underloading by defining cumulative load as the joint effects of body mass index (BMI) and daily walking, and examine the relationship between cumulative load and worsening cartilage damage over 2 years.
Methods
We used data from the Multicenter Osteoarthritis Study. Steps/day, measured by accelerometry, and BMI were calculated at the 60‐month visit. Cartilage damage on magnetic resonance imaging was semiquantitatively scored using the Whole‐Organ Magnetic Resonance Imaging Score (WORMS) at the 60‐month and 84‐month visits; worsening damage was defined as increased WORMS between visits. Risk ratios (RRs) and 95% confidence intervals (95% CIs) were calculated using binomial regression, with adjustment for potential confounders.
Results
Our study included 964 participants, 62% of whom were female, with a mean ± SD age of 66.9 ± 7.5 years. Participants had a mean ± SD BMI of 29.7 ± 4.8 kg/m2 and walked a mean ± SD of 7,153 ± 2,591 steps/day. Participants who walked a moderate number of steps/day (6,000–7,900) or a high number of steps/day (>7,900) and had a high BMI (>31 kg/m2) had a greater risk of worsening medial tibiofemoral (TF) damage (RR 2.83 95% CI 1.46–5.48 and RR 2.61 95% CI 1.50–4.54, respectively) compared with those who walked similar steps/day and had a low BMI (18–27 kg/m2). Participants with a low number of steps/day (<6,000) and a low BMI had a greater risk of worsening medial TF and lateral patellofemoral (PF) damage (RR 2.03 95% CI 1.06–3.92 and RR 2.28 95% CI 1.06–4.85, respectively) compared with those who walked a high number of steps/day and had a low BMI. Effect estimates for other compartments of the knee did not reach statistical significance.
Conclusion
This study provides preliminary evidence that both overloading and underloading may be detrimental to medial TF cartilage, and underloading may be detrimental to lateral PF cartilage.
Objective
This study sought to determine the extent to which physical activity confounds the relation between race and the incidence of osteoarthritis (OA)‐related functional limitation.
Methods
OA ...Initiative study participants with or at increased risk of knee OA who wore an accelerometer were included. Race was self‐reported. Average time spent in moderate to vigorous physical activity (minutes per day) based on ActiGraph uniaxial accelerometer data was assessed. Functional limitation was based on the following: (1) inability to achieve a community walking speed (1.2 m/s) standard, (2) slow walking speed (<1.0 m/s), and (3) low physical functioning based on a Western Ontario and McMaster Universities OA Index (WOMAC) physical function score greater than 28 of 68.
Results
African American (AA) participants (n = 226), compared with White participants (n = 1348), had a higher likelihood of developing functional limitation based on various measures. When adjusted for time in moderate to vigorous physical activity, the association between AA race and inability to walk a community walking speed slightly decreased (from relative risk RR 2.15, 95% confidence interval 95% CI 1.64–2.81, to RR 1.99, 95% CI 1.51–2.61). Association between AA race and other measures of functional limitation mildly decreased (slow walking speed: from RR 2.06, 95% CI 1.40–3.01, to RR 1.82, 95% CI 1.25–2.63; low physical functioning: from RR 3.44, 95% CI 1.96–6.03, to RR 3.10, 95% CI 1.79–5.39). When further adjusted for demographic and other clinical variables, only the association between race and low physical functioning (WOMAC) significantly decreased and no longer met statistical significance.
Conclusion
Greater physical activity is unlikely to completely make up for race differences in OA‐related functional limitation, and other barriers to health equity need to be addressed.
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