Association between bone health and dynapenic obesity in postmenopausal women

AIM

The combination of dynapenia (age-related muscle weakness) and obesity is referred to as dynapenic obesity. We examined the associations between dynapenic obesity and cortical bone thickness and trabecular bone density.

METHODS

The participants were 797 community-dwelling postmenopausal women (with an average age of 62.5 years) who were stratified into normopenia without obesity, dynapenia without obesity (dynapenia), normopenia with obesity (obesity) and dynapenia with obesity (dynapenia obesity) groups based on their grip strength and body fat percentage. Cortical bone thickness and trabecular bone density were measured using ultrasonic bone densitometry. The participants were further divided into those with low cortical bone thickness and low trabecular bone density. Logistic regression analysis was used to identify associated factors.

RESULTS

Individuals with dynapenia (odds ratio [OR] 1.77, 95% confidence interval [CI] 1.16-2.68), obesity (OR 2.46, 95% CI 1.62-3.75) and dynapenic obesity (OR 4.07, 95% CI 2.44-6.79) all significantly increased the odds of low cortical bone thickness. Conversely, the odds of low trabecular bone density were significantly lower in the obesity group (OR 0.65, 95% CI 0.43-0.99) and dynapenic obesity group (OR 0.60, 95% CI 0.37-0.97).

CONCLUSIONS

Dynapenic obesity was found to be associated with cortical bone thinning that might compromise bone health. Postmenopausal women with dynapenic obesity might need to be closely monitored for preserving bone health. Geriatr Gerontol Int 2024; 24: 378-384.

Longitudinal changes in physical activity accumulation patterns during 1-year follow-up in stroke survivors

PURPOSE

Few studies have reported changes in the accumulation patterns of physical activity over a year after stroke. This study characterized the longitudinal changes in physical activity levels and their accumulation patterns for a 1-year follow-up period in stroke survivors.

MATERIALS AND METHODS

In this single-center, prospective, longitudinal observational study, 47 stroke survivors were assessed at rehabilitation discharge and at 6 and 12 months post-discharge. Physical activity was evaluated, and measures included the number of steps, walking duration, total number of bouts per day, and intensity (light, moderate-to-vigorous) and spread (short, medium, and long bouts).

RESULTS

There were no significant main or interaction effects of time on any physical activity variables. Light physical activity accounted for 90% of all walking bouts and 70% of walking duration. Regarding moderate-to-vigorous physical activity (MVPA), 85% of walking bouts and 35% of walking duration were accumulated in short and medium bouts. The number of long-bout MVPA was three per day.

CONCLUSIONS

Physical activity levels and accumulation patterns were highly stable throughout the 12-month follow-up period. Accumulating light physical activity and intermittent MVPA is important for maintaining physical activity levels in stroke survivors. These findings will promote a better understanding of disability and rehabilitation practice.IMPLICATIONS FOR REHABILITATIONPhysical activity levels and accumulation patterns were highly stable throughout the 12-month follow-up period.The accumulation of moderate-to-vigorous physical activity in long bouts might be challenging for stroke survivors.Accumulating light physical activity and intermittent moderate-to-vigorous physical activity may be acceptable for stroke survivors.

The combination of locomotive syndrome and poor sleep quality is a risk factor of falls among community-dwelling middle-aged and older women: A cross-sectional study

AIM

The combination of locomotive syndrome (LS) and poor sleep quality (PQ) has not yet been shown to result in falls or to affect bone conditions in old age and middle age. [Correction added on 1 December 2023, after first online publication: The preceding sentence has been updated for clarity.] METHODS: This cross-sectional study enrolled 2233 community-dwelling middle-aged to older Japanese women. LS and PSQ were assessed by the stand-up test, two-step test, the 25-question Geriatric Locomotive Function Scale, and the Pittsburgh Sleep Quality Index (PSQI). Participants with both LS 1-3 (any) and a PSQI score ≥6 were classified as belonging to the LS(+)/PSQ(+) group. The incidence of falls in the previous month was collected using a self-administered questionnaire. Bone conditions were evaluated using an ultrasonic bone densitometer.

RESULTS

The LS(+)/PSQ(+) group independently had a higher risk of falls after adjusting for confounding factors than the LS(-)/PSQ(-) group using multiple logistic regression analysis (odds ratio 1.92, 95% confidence interval 1.01-3.65, P < 0.05). No relationships between LS(-)/PSQ(+) and LS(+)/PSQ(-) groups and the incidences of fall were observed (P > 0.05). [Correction added on 1 December 2023, after first online publication: The two preceding sentences have been corrected to provide greater clarity.] The LS(+)/PSQ(+) group had lower trabecular bone density and cortical bone thickness than the LS(-)/PSQ(-) group (P < 0.05).

CONCLUSION

The combination of LS and PSQ is an independent risk factor of falls, indicating that assessing both LS and PSQ could be useful in detecting middle-aged and older women with low bone density and thickness who fall easily at an early stage. Geriatr Gerontol Int 2023; 23: 912-918.

Locomotive syndrome and depressive symptoms: A cross-sectional study in middle-aged women

OBJECTIVE

Evidence for an association between locomotive syndrome (LS) and depression is lacking in middle-aged women. This study aimed to investigate the relationship between LS severity and depressive symptoms in community-dwelling middle-aged women.

METHODS

This cross-sectional study included 1,520 middle-aged women (mean age 52 ± 6 years). LS severity was evaluated using the 25-question Geriatric Locomotive Function Scale (GLFS-25) questionnaire and motor function test. Depressive symptoms were assessed using the Zung self-rating depression scale (SDS). Multiple logistic regression analyses were performed to determine the association between depressive symptoms and LS severity, adjusting for potential confounding factors.

RESULTS

LS severity, as evaluated through both questionnaires and motor function tests, was significantly associated with depressive symptoms (SDS ≥ 40 points) in middle-aged women. The relationship between LS and depressive symptoms was only significant when assessed through the GLFS-25 questionnaire rather than the motor function tests. Additionally, a stepwise association was observed between pain severity, as assessed by the GLFS-25, and the prevalence of depressive symptoms.

CONCLUSIONS

LS severity is significantly associated with depressive symptoms in community-dwelling middle-aged women, suggesting the need for additional mental status assessment in participants with LS and concurrent pain.

Bioimpedance phase angle is independently associated with myosteatosis: The Shizuoka study

BACKGROUND & AIMS

Phase angle (PhA) calculated from the resistance and reactance measured using a bioimpedance device was suggested to represent the degree of fat deposition in muscle (myosteatosis), though no direct evidence is available. We aimed to clarify the possible association between PhA and skeletal muscle myosteatosis in community-dwelling middle-aged to older adults.

METHODS

Participants consisted of 424 Japanese (aged ≥50 years). Leg PhA and skeletal muscle mass index (SMI) were obtained by bioelectrical impedance analysis. The mean attenuation values and cross-sectional area of the mid-thigh skeletal muscle were calculated from computed tomography images and considered as indexes of myosteatosis and skeletal muscle mass, respectively.

RESULTS

Leg PhA was positively associated with SMI, and cross-sectional area and mean attenuation value at mid-thigh. Multiple regression analysis adjusted for possible covariates identified leg PhA (β = 0.214) and SMI (β = 0.260) as independent factors of mid-thigh muscle cross-sectional area (P < 0.001), while leg PhA (β = 0.349, P < 0.001) but not SMI (P = 0.645) was associated with mean attenuation value. Similar results were observed in the analysis in the older (≥65 years) subpopulation. The combination of low SMI and low leg PhA showed stepwise association with cross-sectional area, while only individuals with low leg PhA had lower mean attenuated value.

CONCLUSIONS

Leg PhA was independently associated with mean attenuated value of the mid-thigh skeletal muscle, suggesting that the assessment of PhA in combination with SMI could provide additional information for the evaluation of muscle properties.

Eleven new C19-diterpenoid alkaloids from Delphinium elatum cv. Pacific Giant

Diterpenoid alkaloids, the main components of plants of the genera Aconitum, Delphinium, and Garrya, are a group of natural products with notable chemical properties and biological activities. Several C₁₉-diterpenoid alkaloid components from Delphinium elatum cv. Pacific Giant, as well as their derivatives, exhibited cytotoxic activity against lung, prostate, cervical, and vincristine-resistant cervical cancer cell lines. In the current phytochemical investigation on the seeds of D. elatum cv. Pacific Giant, eleven new C₁₉-diterpenoid alkaloids, elapaciline (1), meladine (2), melapacitine (3), iminoeladine (4), 19-oxopaciline (5), 19-oxopacinine (6), N-deethyldelpheline (7), N-deethylpacinine (8), N-deethyl-19-oxoeladine (9), N-deethyl-N-formyleladine (10), and N-deethyl-N-formyldelpheline (11), together with 15 known C₁₉-diterpenoid alkaloids were isolated. Their structures were elucidated by extensive spectroscopic methods including NMR (1D and 2D), IR, and MS (HRMS). Three known diterpenoid alkaloids, 6-dehydrodelcorine (12), delelatine (23), and 6-dehydroeldelidine (24), were isolated for the first time from this plant. Six of the new C₁₉-diterpenoid alkaloids (2, 4-7, and 11) and three of the known diterpenoid alkaloids (18, 23, and 24) were evaluated for cytotoxic activity against five human tumor cell lines.

Sex Differences in Physical Activity in People After Stroke: A Cross-sectional Study

OBJECTIVE

Adequate physical activity after stroke is critical for cardiovascular health. Although sex is a potential factor associated with post-stroke physical activity, its mechanism remains unclear. This study aimed to examine sex differences in human physical activity following stroke.

METHOD

A cross-sectional study with 62 participants (men: 42, women: 20) was conducted. Physical activity was measured for three consecutive days using a step activity monitor. The walking durations per day in light physical activity, moderate-to-vigorous physical activity, and total physical activity were calculated. Sex differences in walking duration were compared using Welch's t-tests or Mann-Whitney U tests.

RESULTS

Women had a significantly greater walking duration in light physical activity and in total than did the men. In contrast, no significant differences were found in moderate-to-vigorous physical activity.

CONCLUSION

This study reported sex differences in the walking duration after stroke. Moreover, it found that women spent more time in low intensity physical activity than men. Our results will be useful for planning interventions to increase physical activity and decrease sedentary behavior after stroke.

Does a Cognitive Task Promote Implicit or Explicit Motor Learning?

This study examined whether use of an N-back task could promote implicit and explicit motor learning. In Experiment 1, 30 healthy adults were assigned to an N-back task group (NTG) or a control task group (CG). All participants performed the serial reaction time task (SRTT) and generation task after either the N-back or control tasks. The results did not reveal whether the N-back task promoted implicit or explicit motor learning because participants in the NTG noticed a hidden loop in the SRTT and this "awareness" made it difficult to interpret the results in Experiment 1. In Experiment 2, we examined whether the N-back task promoted explicit motor learning only using a modified SRTT. Thirty healthy adults were assigned to the NTG or the CG. On day 1, all participants performed the modified SRTT after either the N-back or control tasks. On day 7, all participants repeated the modified SRTT. As a result, the performance on the modified SRTT was faster in the NTG than in the CG on days 1 and 7. In summary, although the N-back task might promote explicit motor learning, the present study could not clearly conclude whether the N-back task promoted implicit and explicit motor learning.

Enhancement of prefrontal area excitability induced by a cognitive task: Impact on subsequence visuomotor task performance

Cognitive tasks may have the potential to improve visuomotor task performance; however, the reason for this is unclear. If this can be clarified, it may be possible to develop clinically valuable outcomes, such as promotion of motor learning though cognitive tasks. The present study aimed to investigate whether changes in prefrontal area excitability induced by cognitive tasks, especially within the dorsolateral prefrontal cortex (DLPFC), influenced the speed of improvement during visuomotor task performance. Twenty young healthy adults were recruited. The serial reaction time task (SRTT) was used to assess visuomotor task performance. Cognitive tasks included an adjusted N-back task, a non-adjusted N-back task, and a control task, which were evaluated on different days. Additionally, we measured cerebral hemodynamic activity using near-infrared spectroscopy while each cognitive task was being performed. We observed that the adjusted N-back task significantly enhanced the speed of improvement during the SRTT performance compared to the control task. However, there was no relationship between the speed of improvement during the SRTT performance and changes in prefrontal area excitability induced by the cognitive tasks. Our findings contribute towards developing an effective method that uses cognitive tasks to promote visuomotor learning.

Characteristics of frontal plane lower limb movement during walking in patients with knee osteoarthritis of varying severity

PURPOSE

This study aimed to investigate the effect of knee joint structural destruction on frontal plane hip and ankle joint kinematics and kinetics during the stance phase of walking in patients with differing severities of knee osteoarthritis (KOA).

METHODS

An early KOA group consisted of eight subjects with bilateral knee Kellgren-Lawrence (KL) scale scores of 1 or 2. An established KOA group comprised nine subjects (18 knees) with KL scores of 3 or 4. To measure walking, the data were obtained using the motion analysis system and force plates. From the ground reaction force data, the stance phase of gait was divided into five periods.

RESULTS

In the established KOA group, the hip joint was significantly abducted, and the knee joint had significantly greater varus positioning during the stance phase. In addition, in the established KOA group, a significant knee abductor moment was observed during the stance phase. In contrast, in the early KOA group, the ankle joint showed a significant inversion moment during the stance phase, but in the established KOA group, the ankle joint moment was very small.

CONCLUSIONS

The structural destruction of the knee joint in the frontal plane in patients with the established KOA changes the movement of the hip and the moment of the ankle.

Differences in skill level influence the effects of visual feedback on motor learning

[Purpose] No previous studies have confirmed whether the effects of visual feedback on motor learning vary according to learner skill level for a learning task. The purpose of this study was to clarify whether differences in skill influence the effects of visual feedback on motor learning. [Participants and Methods] Sixty-four participants were assigned to one of four different feedback groups (concurrent-100%, concurrent-50%, terminal-100%, or terminal-50%). The learning task was to adjust the load amount continuously to the left lower limb in accordance with sound stimulation at intervals of 1 Hz. The four groups performed a pretest, practice sessions, and a retention test 24 hours after practice. After completing these measurements, the participants were classified as either high- or low-skilled based on the results of the pretest. [Results] Only the groups of low-skilled participants who used concurrent feedback showed lower root mean square errors in the retention test compared to in the pretest. [Conclusion] Differences in skill level for the same task influenced the effects of visual feedback on motor learning. Furthermore, concurrent visual feedback can help improve motor learning in low-skilled learners for the same task.

Repetition of a cognitive task promotes motor learning

Motor learning plays an important role in the acquisition of new motor skills. In this study, we investigated whether repetition of a cognitive task promoted motor learning. Fifty-one young adults were assigned to either the early, late, or control groups. All participants completed a mouse tracking task in which they manipulated a mouse to track a moving target on a screen. The cursor was rotated 165° in the counterclockwise direction from the actual mouse position, requiring participants to learn how to use a new tool. To determine the task performance, we calculated the distance between the cursor and target position. In addition, to assess the effects of a cognitive task on the progress of motor learning, curve fitting of the learning curves was performed for the total distance. Experiments were conducted as per the following schedule: learning day 1 (L1), learning day 2 (L2: the day after learning day 1), retention day 1 (R1: 2 weeks after learning day 1), and retention day 2 (R2: 4 weeks after learning day 1). Participants underwent mouse tracking for 20 min on L1 and L2 and for 3 min on R1 and R2. As a cognitive task, we adopted the N-back task. The early or late group performed the N-back task for 20 min before performing motor tracking task on L1 or L2, respectively. The control group did not perform the N-back task. Based on curve fitting analysis, it was observed that the rate of change for motor learning in the early group was higher than that in the control group. The retention of motor learning did not differ between all groups. Our results indicate that the repetition of a cognitive task enhanced in the early phase of motor learning of the mouse tracking task.

Walking activity in community-dwelling stroke survivors within 1 month after discharge from a rehabilitation setting

Objective: To characterize the pattern of activity accumulation in stroke survivors.Method: Nineteen stroke patients and 19 age-sex-matched healthy adults participated. Step counts were measured using a step activity monitor for 3 d. The steps per day, bouts per day, walking time per day, average steps per bout, and average walking time per bout were calculated in each walking-distance category (short, medium, and long-distance bout) and in total.Results: The total steps per day were 8446 and 11,749 steps in stroke survivors and control participants, respectively. The total steps per day and the total bouts per day for the stroke group were both significantly lower compared with the control group. Significant group differences were found in only the medium-distance range. No significant differences were found in average steps per bout.Conclusion: Fewer number of bouts is a characteristic pattern of walking activity in stroke survivors. In particular, a low number of medium-distance bouts in stroke survivors results in a low number of daily steps when compared with healthy adults. To facilitate physical activity in stroke survivors, not only the total number of bouts per day but the number of bouts of varying lengths must be considered. Implications for rehabilitationFewer number of bouts is a characteristic pattern of walking activity in stroke survivors.Low number of bouts, especially medium-distance bouts, in stroke survivors, results in low number of daily steps when compared with healthy adults.The number of long-distance bouts is important for increasing total daily steps after stroke with mild disability.To facilitate physical activity in stroke survivors, not only the total number of bouts per day but the number of bouts of varying lengths must be considered.

Smoothness of the knee joint movement during the stance phase in patients with severe knee osteoarthritis

Background

Patients with knee osteoarthritis can significantly affect the function of the knee joint in terms of joint range and mobility and have a stereotypical pattern of knee stiffness during gait, caused by an increased resistance in the muscles and soft tissues during the stance phase of knee joint movement. Smoothness in movement, such as during walking and running, is assumed to be attained by adulthood; however, disruptions in gait pattern due to injury or performance enhancement can alter the smoothness of the movement, and this is often quantified in terms of "jerk". A higher jerk value is linked with a decrease in smoothness. However few have reported to evaluate the smoothness of the knee joint movement during walking in patients with knee osteoarthritis. The purpose of the present study was to quantify the smoothness of the knee joint movement during walking in people with knee osteoarthritis.

Methods

Patients were classified as having early or severe knee osteoarthritis. There were eight patients in each group (16 knees; three males, five females). The normalized angular jerk was calculated as an indicator of the walking knee joint smoothness in each of the four periods of the stance phase. Two-way ANOVA was performed to compare the smoothness of knee joint movement between groups and between each period of the stance phase.

Results

The angular change in the sagittal plane of those with severe knee osteoarthritis was smaller than that of those with early knee osteoarthritis in all periods of the stance phase. Normalized angular jerk did not significantly differ between groups in all periods. In both groups, the normalized angular jerk in the sagittal plane was significantly larger in the mid-stance and terminal stance periods than in the early stance and pre-swing periods. Only in patients with severe knee osteoarthritis, there was a significantly larger jerk in the frontal plane in the mid-stance period.

Conclusion

The present results revealed that the smoothness of joint movement decreases during the single leg supporting phase of the stance phase in the frontal plane with severe knee osteoarthritis, although there is no difference in smoothness of joint movement according to the severity of knee osteoarthritis The instability during single leg support due to increase of the knee joint load and destruction cause the impaired smoothness of the knee joint movement.

Scanning wave photopolymerization enables dye-free alignment patterning of liquid crystals

Hierarchical control of two-dimensional (2D) molecular alignment patterns over large areas is essential for designing high-functional organic materials and devices. However, even by the most powerful current methods, dye molecules that discolor and destabilize the materials need to be doped in, complicating the process. We present a dye-free alignment patterning technique, based on a scanning wave photopolymerization (SWaP) concept, that achieves a spatial light-triggered mass flow to direct molecular order using scanning light to propagate the wavefront. This enables one to generate macroscopic, arbitrary 2D alignment patterns in a wide variety of optically transparent polymer films from various polymerizable mesogens with sufficiently high birefringence (>0.1) merely by single-step photopolymerization, without alignment layers or polarized light sources. A set of 150,000 arrays of a radial alignment pattern with a size of 27.4 μm × 27.4 μm were successfully inscribed by SWaP, in which each individual pattern is smaller by a factor of 10⁴ than that achievable by conventional photoalignment methods. This dye-free inscription of microscopic, complex alignment patterns over large areas provides a new pathway for designing higher-performance optical and mechanical devices.

Age effects on the control of dynamic balance during step adjustments under temporal constraints

This study investigated the age effects on the control of dynamic balance during step adjustments under temporal constraints. Fifteen young adults and 14 older adults avoided a virtual white planar obstacle by lengthening or shortening their steps under free or constrained conditions. In the anterior-posterior direction, older adults demonstrated significantly decreased center of mass velocity at the swing foot contact under temporal constraints. Additionally, the distances between the 'extrapolated center of mass' position and base of support at the swing foot contact were greater in older adults than young adults. In the mediolateral direction, center of mass displacement was significantly increased in older adults compared with young adults. Consequently, older adults showed a significantly increased step width at the swing foot contact in the constraint condition. Overall, these data suggest that older adults demonstrate a conservative strategy to maintain anterior-posterior stability. By contrast, although older adults are able to modulate their step width to maintain mediolateral dynamic balance, age-related changes in mediolateral balance control under temporal constraints may increase the risk of falls in the lateral direction during obstacle negotiation.

Effects of temporal constraints on medio-lateral stability when negotiating obstacles

If an obstacle suddenly appears during walking, either the crossing step can be lengthened or the precrossing step shortened to avoid the obstacle. We investigated the effects of temporal constraints on dynamic stability during step adjustments. Twelve healthy young adults avoided a virtual white planar obstacle by lengthening or shortening their steps under free or constrained conditions. When constrained, participants had only one step to avoid the obstacle. The results indicated that center of mass (COM) displacement in the mediolateral (ML) direction and the COM velocity toward the swing-leg side during the crossing step were significantly increased in the long-constraint compared with the long-free condition. Consequently, the extrapolated COM (XcoM) position at the swing foot contact was also located further toward the swing-leg side. However, the distances between the XcoM and base of support (BOS) at the swing foot contact in the ML direction was unchanged because of greater lateral foot placement. In the anteriorposterior (AP) direction, temporal constraints led to greater AP COM displacement. The XcoM-BOS distance in the AP direction was unchanged in the long-constraint condition because of greater step length. However, the value became negative in the short-constraint condition, violating the conditions for dynamic stability, because step length adjustments were obstructed by the spatial constraints of the obstacles. These results suggest that temporal constraints affect postural stability in the AP and ML directions during step adjustments. AP and ML stability at swing foot contact are maintained through adjustments of step length and lateral foot placement, respectively.

Isolation and characterization of Midway virus: a new tick-borne virus related to Nyamanini

Midway virus, a new tick-borne virus isolated from two species of Ornithodoros (Alectorobius) ticks of the capensis group (O capensis, O denmarki), is described from Midway, Kure, and Manana islands in the Central Pacific (Hawaiian Archipelago) and from northern Honshu (Japan). Midway virion is enveloped, unusually large, acid and temperature sensitive, and its type of nucleic acid is RNA. Complement-fixation (CF) tests show a close relation of Midway to Nyamanini virus, which has been isolated from ardeid birds and Argas ticks in Africa, the Indian subcontinent, and Southeastern Asia. However, cross-box tests (CF, mouse and tissue culture neutralization, immunofluorescence) show that these two viruses are quite distinct. Midway virus is lethal for newborn Swiss mice inoculated by intracerebral, but not intraperitoneal route. It fails to kill four-week-old mice by either route. Midway virus causes cytopathic effects in BHK-21 cells and titerable plaques in Vero cells. Antibodies to it were prevalent among nestlings of Larus crassirostris (Black-tailed Gull) on Aomatsushima I., but were scarce among those of Nycticorax nycticorax (Black-crowned Night Heron) of the same island.