Reduced plasma calcitonin gene-related peptide level identified in cluster headache: A prospective and controlled study

BACKGROUND

The role of calcitonin gene-related peptide (CGRP) in the cyclic pattern of cluster headache is unclear. To acquire biological insight and to comprehend why only episodic cluster headache responds to CGRP monoclonal antibodies, we examined whether plasma CGRP changes between disease states (i.e. bout, remission and chronic) and controls.

METHODS

The present study is a prospective case-control study. Participants with episodic cluster headache were sampled twice (bout and remission). Participants with chronic cluster headache and controls were sampled once. CGRP concentrations were measured in plasma with a validated radioimmunoassay.

RESULTS

Plasma was collected from 201 participants diagnosed with cluster headache according to the International Classification of Headache Disorders, 3rd edition, and from 100 age- and sex-matched controls. Overall, plasma CGRP levels were significantly lower in participants with cluster headache compared to controls (p < 0.05). In episodic cluster headache, CGRP levels were higher in bout than in remission (mean difference: 17.1 pmol/L, 95% confidence interval = 9.8-24.3, p < 0.0001). CGRP levels in bout were not different from chronic cluster headache (p = 0.266).

CONCLUSIONS

Plasma CGRP is unsuitable as a diagnostic biomarker of cluster headache or its disease states. The identified reduced CGRP levels suggest that CGRPs role in cluster headache is highly complex and future investigations are needed into the modulation of CGRP and its receptors.

Adherence to the WHO recommendation of three weekly days of vigorous intensity activities in children: an accelerometry study of vigorous physical activity bouts

Background

The World Health Organization (WHO) recommends that children and adolescents incorporate vigorous intensity activities (VIAs) at least three days a week. This recommendation has not been sufficiently studied using objective methods, such as accelerometry. Physical education classes and extracurricular sports activities are optimal opportunities for compliance with this recommendation.

Objective

To identify VIAs through bouts of vigorous physical activity (VPA-Bouts) evaluated with accelerometry and, with this, to know the compliance with the recommendation on VIAs.

Methods

A cross-sectional study of the habitual physical activity of 353 children (8-9 years old) was carried out using accelerometry and participation in organized extracurricular sports activities was asked through a questionnaire. School days with and without physical education class, weekends, and the average weekly day were identified, as well as school time and out-of-school time. A VPA-Bout was defined as an interval of at least 60 minutes with a proportion of VPA of at least 16.7% in boys and 12.5% in girls (10.0 and 7.5 minutes/hour of VPA, respectively).

Results

The average daily time in organized extracurricular sports activities declared by questionnaire and the average daily duration of the VPA-Bouts evaluated with accelerometers in the extracurricular period was 21.3 (SD 19.8) and 23.9 (SD 31.2) minutes, respectively, in boys, whereas, in girls it was 20.2 (SD 17.4) and 11.0 (SD 16.9) minutes, respectively. In school time including a physical education class, there was a higher proportion of VPA-Bouts than without these classes (with: 28.6%, without: 2.1%, p < 0.001). Children who reported at least three weekly hours of organized extracurricular sports activities accumulated a higher proportion of school afternoons with VPA-Bouts than those with fewer weekly hours of this type of activities (≥3 hours/week: 27.5%, <3 hours/week: 9.3%, p < 0.001). On the weekend, boys who reported at least three weekly hours of organized extracurricular sports activities performed more VPA-Bouts than those participating in less weekly hours, while in girls no significant differences were observed (weekend; boys, ≥3 hours/week: 26.0%, <3 hours/week: 9.0%, p < 0.001; girls: 8.3%, 8.0%, p = 0.917). Compliance with the recommendation to incorporate VIAs at least three days a week was 23.8%. Children who reported at least three weekly hours of extracurricular sports activities achieved higher compliance than those who reported fewer extracurricular activities (≥3 hours/week: 35.1%, <3 hours/week: 12.7%, p < 0.001). Additionally, boys showed higher compliance rates than girls (boys: 32.9%, girls: 15.3%, p < 0.001).

Conclusion

One in every four children met the WHO recommendation to incorporate VIAs at least three days a week, as evaluated by accelerometry. Physical education classes and extracurricular organized sports activities contributed to compliance with this recommendation.

Does gait bout definition influence the ability to discriminate gait quality between people with and without multiple sclerosis during daily life?

BACKGROUND

There is currently no consensus about standardized gait bout definitions when passively monitoring walking during normal daily life activities. It is also not known how different definitions of a gait bout in daily life monitoring affects the ability to distinguish pathological gait quality. Specifically, how many seconds of a pause with no walking indicates an end to one gait bout and the start of another bout? In this study, we investigated the effect of 3 gait bout definitions on the discriminative ability to distinguish quality of walking in people with multiple sclerosis (MS) from healthy control subjects (HC) during a week of daily living.

METHODS

15 subjects with MS and 16 HC wore instrumented socks on each foot and one Opal sensor over the lower lumbar area for a week of daily activities for at least 8 h/day. Three gait bout definitions were based on the length of the pause between the end of one gait bout and start of another bout (1.25 s, 2.50 s, and 5.0 s pause). Area under the curve (AUC) was used to compare gait quality measures in MS versus HC.

RESULTS

Total number of gait bouts over the week were statistically significantly different across bout definitions, as expected. However, AUCs of gait quality measures (such as gait speed, stride length, stride time) discriminating people with MS from HC were not different despite the 3 bout definitions.

SIGNIFICANCE

Quality of gait measures that discriminate MS from HC during daily life are not influenced by the length of a gait bout, despite large differences in quantity of gait across bout definitions. Thus, gait quality measures in people with MS versus controls can be compared across studies using different gait bout definitions with pause lengths ≤5 s.

A computational formulation of the behavior systems account of the temporal organization of motivated behavior

The behavior systems framework suggests that motivated behavior-e.g., seeking food and mates, avoiding predators-consists of sequences of actions organized within nested behavioral states. This framework has bridged behavioral ecology and experimental psychology, providing key insights into critical behavioral processes. In particular, the behavior systems framework entails a particular organization of behavior over time. The present paper examines whether such organization emerges from a generic Markov process, where the current behavioral state determines the probability distribution of subsequent behavioral states. This proposition is developed as a systematic examination of increasingly complex Markov models, seeking a computational formulation that balances adherence to the behavior systems approach, parsimony, and conformity to data. As a result of this exercise, a nonstationary partially hidden Markov model is selected as a computational formulation of the predatory subsystem. It is noted that the temporal distribution of discrete responses may further unveil the structure and parameters of the model but, without proper mathematical modeling, these discrete responses may be misleading. Opportunities for further elaboration of the proposed computational formulation are identified, including developments in its architecture, extensions to defensive and reproductive subsystems, and methodological refinements.

[Descriptive epidemiology of accelerometer-measured moderate to vigorous physical activity in Japanese older adults]

AIM

Most physical activity (PA) guidelines for health promotion recommend moderate to vigorous PA (MVPA) lasting at least 10 minutes (long-bout MVPA). However, recent studies have shown the beneficial effects of short-bout MVPA (intermittent and lasting <10 minutes). Therefore, we aimed to clarify the detailed patterns of MVPA of community-dwelling older adults using accelerometers.

METHODS

This is a cross-sectional descriptive study. Community-dwelling older Japanese adults (total: 1,210; 70-80 years of age) randomly selected from residential registries of 3 municipalities (Bunkyo, Fuchu, and Oyama) were asked to wear an accelerometer (HJA-350 IT; Omron Healthcare, Japan). MVPA was classified by bout length (1-4, 5-9, 10-19, 20-29, and > 30 minutes). The mean frequency and duration of MVPA by each bout length and the proportion of long-bout MVPA were described.

RESULTS

Valid data were obtained from 450 participants (men: 56.7%; mean age: 74 years). The mean±standard deviation of the frequency and duration of MVPA bouts were 21.8±14.6 times/day and 2.1±0.9 min, respectively. The total duration of MVPA was 46.5±33.0 min/day. Long-bout MVPA accounted for 26.9%±23.5% of daily MVPA, whereas MVPA of 1-4 minutes accounted for 43.4%.

CONCLUSIONS

Older adults performed about 45 minutes of MVPA a day, but most of this was short-bout MVPA, which is overlooked by current WHO PA guidelines. In particular, short-bout MVPA was frequent among older women and those living in rural areas.

Modeling bout-pause response patterns in variable-ratio and variable-interval schedules using hierarchical Bayesian methodology

Streams of operant responses are arranged in bouts separated by pauses and differences in performance in reinforcement schedules with identical inter-reinforcement intervals (IRIs) are primarily due to differences in within-bout response rate, not in bout-initiation rate. The present study used hierarchical Bayesian modeling as a new method to quantify the properties of the response bout. A Bernoulli distribution was utilized to express the probability to stay in bout/pause, while a Poisson distribution was utilized to quantify the within-bout response rates. We compared bout/pause patterns between variable-ratio (VR) and variable-interval (VI) schedules across IRIs. The model estimation revealed no difference in within-bout staying probability between schedules. However, response rates of within-bout responses were higher in VR than VI across IRIs. These results are consistent with previous analyses using a log-survivor plot to describe within-bout responses and bouts-initiation responses. In addition, a simulation study was performed to examine how sensitively the model estimate the parameters according to different bout initiation rates. These result showed that the within-bout staying probability was affected by changes in between-bout while within-bout response rate parameters were not. This suggests model estimation robustness of the model estimation to dissociate within-bout and between-bout parameters during different reinforcement schedules.

Peptide YY induces characteristic meal patterns of aged mice

BACKGROUND & AIM

Changes in eating behavior occur in the elderly due to oral and swallowing dysfunctions. We aimed to clarify the difference between basal meal patterns of young and aged mice in relation to appetite regulating hormones.

METHODS

Thirty two of young (7-week-old) and aged (23-25-month-old) C57BL/6 male mice were acclimated to a single housing and then transferred to a highly sensitive automated feeding monitoring device. Feeding behavior was monitored from the onset of the dark phase after habituation to the device. Plasma peptide YY (PYY) levels were assessed under the several feeding status or after treatment of PYY. PYY and its receptor (NPY Y2 receptor, Y2R) antagonist were intraperitoneally administered 30min before the monitoring.

RESULTS

Although the basal 24-h meal amounts did not differ by age, the total meal time and frequency of minimum feeding activity (bout) were significantly increased and the average bout size and time per bout were significantly decreased in aged mice. PYY dynamics were abnormal and the temporal reduction in food intake by exogenous PYY was more prominent in aged mice than in young mice. PYY administration to young mice induced aged-like meal patterns, and Y2R antagonist administration to aged mice induced young-like meal patterns.

CONCLUSIONS

Aged mice exhibited characteristic meal patterns probably due to PYY metabolism dysfunction and/or enhanced PYY-Y2R signaling, suggesting a novel method for assessing eating difficulties in aged animals and a potential target for the remedy.