Consumer-Based Activity Trackers as a Tool for Physical Activity Monitoring in Epidemiological Studies During the COVID-19 Pandemic: Development and Usability Study

BackgroundConsumer-based physical activity trackers have increased in popularity. The widespread use of these devices and the long-term nature of the recorded data provides a valuable source of physical activity data for epidemiological research. The challenges include the large heterogeneity between activity tracker models in terms of available data types, the accuracy of recorded data, and how this data can be shared between different providers and third-party systems.ObjectiveThe aim of this study is to develop a system to record data on physical activity from different providers of consumer-based activity trackers and to examine its usability as a tool for physical activity monitoring in epidemiological research. The longitudinal nature of the data and the concurrent pandemic outbreak allowed us to show how the system can be used for surveillance of physical activity levels before, during, and after a COVID-19 lockdown.MethodsWe developed a system (mSpider) for automatic recording of data on physical activity from participants wearing activity trackers from Apple, Fitbit, Garmin, Oura, Polar, Samsung, and Withings, as well as trackers storing data in Google Fit and Apple Health. To test the system throughout development, we recruited 35 volunteers to wear a provided activity tracker from early 2019 and onward. In addition, we recruited 113 participants with privately owned activity trackers worn before, during, and after the COVID-19 lockdown in Norway. We examined monthly changes in the number of steps, minutes of moderate-to-vigorous physical activity, and activity energy expenditure between 2019 and 2020 using bar plots and two-sided paired sample t tests and Wilcoxon signed-rank tests.ResultsCompared to March 2019, there was a significant reduction in mean step count and mean activity energy expenditure during the March 2020 lockdown period. The reduction in steps and activity energy expenditure was temporary, and the following monthly comparisons showed no significant change between 2019 and 2020. A small significant increase in moderate-to-vigorous physical activity was observed for several monthly comparisons after the lockdown period and when comparing March-December 2019 with March-December 2020.ConclusionsmSpider is a working prototype currently able to record physical activity data from providers of consumer-based activity trackers. The system was successfully used to examine changes in physical activity levels during the COVID-19 period.     

Antibodies to surface IgM and IgD increase the expression of various class II antigens on human B cells

Antibodies to surface IgM and IgD were found to induce increased expression of class II antigens on normal and neoplastic human B cells within 24 h of stimulation. Antigens associated with different class II sub-locus genes (DC, DR and SB) were all found to be increased as determined by monoclonal antibodies (Leu-10 and B 3/4 for DC, D 1/12 for DR and MHM4 for SB-associated antigens). The increased expression of class II antigens was selective as anti-immunoglobulins failed to increase expression of other surface antigens such as B1 and beta 2-microglobulin. The effect of anti-mu and anti-delta could be blocked specifically by corresponding myeloma proteins suggesting that antibodies to surface IgM and IgD, respectively, were responsible for the effect observed. Moreover, antibodies to another surface antigen (B1) failed to induce such changes. Increased class II antigen expression appeared to be dependent on protein synthesis, and early changes in ion fluxes, but could not be elicited by membrane depolarization as reported in murine systems.     

Composite cerebral neuroblastoma and astrocytoma. A mixed central neuroepithelial tumor

This report describes an exceptional example of cerebral neuroblastoma in association with neoplastic glial cells, which were frequently arranged in clusters around the supporting blood vessels. The neuroblastic nature of the tumor was confirmed by the presence of numerous dense-core vesicles in the cell processes. The glial nature of the associated cells was confirmed by their positivity for glial fibrillary acid protein by immunoperoxidase staining and by the presence of abundant cytoplasmic filaments of intermediate size on electron microscopy. Of particular interest was the presence of dense-core vesicles in some of the glial cells, and that of a basal lamina underlying the perivascular glial cells. The tumor was interpreted as a composite cerebral neuroblastoma and astrocytoma. No undifferentiated neuroepithelial stem cells could be identified. The cytogenesis of this mixed neuroepithelial neoplasm is uncertain.     

No release of interstitial glutamate in experimental human model of muscle pain.

Glutamate may be released from muscle nociceptors and thereby contribute to mechanisms underlying acute and chronic muscle pain. In vivo concentration of glutamate during muscle pain has not previously been studied in either animals or humans. In the present study, we aimed to study the in vivo concentration of glutamate before, during and after acute pain of trapezius muscle in humans using the microdialysis technique. In addition, we examined the nutritive skeletal muscle blood flow and the interstitial concentrations of lactate, glucose, glycerol, pyruvate and urea. Experimental pain and tenderness were induced by intramuscular infusion of a chemical mixture consisting of bradykinin, prostaglandin E(2), histamine and serotonin. One EMG-needle and one microdialysis catheter were inserted into non-dominant and dominant trapezius muscles on a standard anatomical point in 19 healthy subjects. Dialysates were collected at rest, during infusion and 60 and 120 min after stop of infusion. Local tenderness was recorded at baseline and at the end of experiment. Local pain was recorded during infusion. The infusion of chemical mixture was more painful than infusion of placebo (p < 0.05) and resulted in significantly higher local tenderness score than placebo (p = 0.007). There was no difference in change in interstitial concentrations of glutamate, lactate, glucose, glycerol, pyruvate and urea from baseline to infusion and post-infusion periods between chemical mixture and placebo (p > 0.05). Muscle blood flow increased significantly over time in response to infusion of chemical mixture and placebo (p = 0.001). However, we found no difference in changes in muscle blood flow between chemical mixture and placebo (p > 0.05). In conclusion, the present study demonstrates no signs of increased release of glutamate from myofascial nociceptors during and after acute experimentally induced muscle pain and tenderness.     

Neurocognitive functioning and suicidality in schizophrenia spectrum disorders

Objective

The aim of this study was to investigate whether suicide attempters had higher IQ, better executive functioning, or were more impulsive as measured by neuropsychological tests than non-attempters in a group of patients with schizophrenia spectrum disorders.

Method

One hundred seventy-four patients with schizophrenia spectrum disorders were assessed with a clinical interview for diagnosis, suicidality, symptoms and function, and underwent an extensive neurocognitive test battery.

Results

There were no statistically significant differences in any neurocognitive domains between lifetime suicide attempters and non-attempters, or between patients with different rates of suicide attempts. Currently suicidal patients were significantly more impulsive (had poorer inhibitory control) than currently non-suicidal patients, but this difference was mediated by positive psychotic symptoms.

Conclusion

The findings indicate that among patients with schizophrenia spectrum disorders, there are no significant differences in IQ or neurocognitive functioning between suicide attempters and non-attempters.     

Critical role of aquaporin-4 (AQP4) in astrocytic Ca2+ signaling events elicited by cerebral edema

Aquaporin-4 (AQP4) is a primary influx route for water during brain edema formation. Here, we provide evidence that brain swelling triggers Ca(2+) signaling in astrocytes and that deletion of the Aqp4 gene markedly interferes with these events. Using in vivo two-photon imaging, we show that hypoosmotic stress (20% reduction in osmolarity) initiates astrocytic Ca(2+) spikes and that deletion of Aqp4 reduces these signals. The Ca(2+) signals are partly dependent on activation of P2 purinergic receptors, which was judged from the effects of appropriate antagonists applied to cortical slices. Supporting the involvement of purinergic signaling, osmotic stress was found to induce ATP release from cultured astrocytes in an AQP4-dependent manner. Our results suggest that AQP4 not only serves as an influx route for water but also is critical for initiating downstream signaling events that may affect and potentially exacerbate the pathological outcome in clinical conditions associated with brain edema.     

Job stress in young physicians with an emphasis on the work-home interface: a nine-year, nationwide and longitudinal study of its course and predictors

Although physicians are known to experience more stress than other workers, knowledge is lacking on the course of stress from a longitudinal perspective. This study explored the course of and contributors to, different dimensions of early career job-stress among physicians by means of a nationwide mail survey, with a particular emphasis on stress relating to the work-home interference. All physicians graduating from all four Norwegian universities in 1993 / 94 (N=631), responded during their final year of medical school (N=522), during their internship (N=402), in their 4th postgraduate year (N=422), and in their 10th postgraduate year (N=390). The mean observation period was 9.2 yr (SD=0.5). The main outcomes were job stress dimensions derived from an established job stress questionnaire (Cooper / Tyssen), with emphasis placed on dimensions of the work-home interference. Stress relating to the work-home interference increased during the observation period for both genders (repeated measures: beta=0.06, p<0.05), whereas stress relating to emotional pressure, time pressure, and fear of complaints and criticism, decreased. Stress relating to the work-home interference increased during their early career, mainly due to a lack of adaptive reduction in work hours and an increased number of children. Neuroticism, conscientiousness, and lack of support from one's partner and colleagues, appeared to be predictive of this stress.