Workplace Standing Desks and Arterial Stiffness

Many jobs in today’s society require sitting at a desk with little physical activity. Individuals who engage in ten hours of sedentary behavior per day double their CVD risk. Standing desks are thought to decrease sedentary time and improve cardiovascular health. Acute use of standing desks is shown to lower PWV. However, chronic effects remain unknown. Forty eight participants qualified as seated (19 females, 5 males: age 41 ± 2 years, BMI 25 ± 1 kg/m2) or standing (21 females, 3 males: age 45 ± 2 years, BMI 25 ± 1 kg/m2) groups based on habitual workplace use. Arterial stiffness was assessed as pulse wave velocity (PWV) by using applanation tonometry in conjunction with electrocardiography. No differences were detected in carotid-femoral PWV (cfPWV) between seated and standing groups (p = 0.47). However, age (p \u3c 0.01), aerobic fitness (p \u3c 0.01), and fat percentage (p = 0.02) classifications revealed significant differences between groups. Standing for 50% of a workday does not affect cfPWV. Although, cardiorespiratory fitness and healthy body composition are associated with less arterial stiffness

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Sex differences in self-report anxiety and sleep quality during COVID-19 stay-at-home orders

Background: COVID-19 and home isolation has impacted quality of life, but the perceived impact on anxiety and sleep remains equivocal. The purpose of this study was to assess the impact of COVID-19 and stay-at-home orders on self-report anxiety and sleep quality, with a focus on sex differences. We hypothesized that the COVID-19 pandemic would be associated with increased anxiety and decreased sleep quality, with stronger associations in women. Methods: One hundred three participants (61 female, 38 ± 1 years) reported perceived changes in anxiety and sleep quality due to stay-at-home orders during the COVID-19 pandemic and were administered the Spielberger State-Trait Anxiety Inventory (STAI), Pittsburgh Sleep Quality Index (PSQI), and Insomnia Severity Index (ISI). Chi-square and T test analyses were utilized to assess sex differences in reported anxiety and sleep. Analysis of covariance was used to compare the associations between reported impact of COVID-19 and anxiety/sleep parameters. Results: Women (80.3%) reported higher prevalence of increased general anxiety due to COVID-19 when compared to men (50%; p = 0.001) and elevated STAI state anxiety compared to men (43 ± 1 vs. 38 ± 1 a.u., p = 0.007). Despite these differences in anxiety, the perceived impact of COVID-19 on PSQI was not different between sexes. However, when stratified by perceived changes in anxiety due to COVID-19, participants with higher anxiety responses to COVID-19 had higher ISI compared to those with no perceived changes in anxiety (9 ± 1 vs. 5 ± 1 a.u., p = 0.003). Additionally, participants who reported reduced sleep quality due to COVID-19 reported higher state anxiety (45 ± 1 a.u.) compared to those that perceived no change (36 ± 2 a.u., p = 0.002) or increased (36 ± 2 a.u., p \u3c 0.001) sleep quality. Conclusion: COVID-19 and state-ordered home isolation was associated with higher anxiety and reduced sleep quality, with a stronger association in women with respect to anxiety

Significance analysis of microarray transcript levels in time series experiments

Background: Microarray time series studies are essential to understand the dynamics of molecular events. In order to limit the analysis to those genes that change expression over time, a first necessary step is to select differentially expressed transcripts. A variety of methods have been proposed to this purpose; however, these methods are seldom applicable in practice since they require a large number of replicates, often available only for a limited number of samples. In this data-poor context, we evaluate the performance of three selection methods, using synthetic data, over a range of experimental conditions. Application to real data is also discussed. Results: Three methods are considered, to assess differentially expressed genes in data-poor conditions. Method 1 uses a threshold on individual samples based on a model of the experimental error. Method 2 calculates the area of the region bounded by the time series expression profiles, and considers the gene differentially expressed if the area exceeds a threshold based on a model of the experimental error. These two methods are compared to Method 3, recently proposed in the literature, which exploits splines fit to compare time series profiles. Application of the three methods to synthetic data indicates that Method 2 outperforms the other two both in Precision and Recall when short time series are analyzed, while Method 3 outperforms the other two for long time series. Conclusion: These results help to address the choice of the algorithm to be used in data-poor time series expression study, depending on the length of the time series

Dihydrotestosterone treatment rescues the decline in protein synthesis as a result of sarcopenia in isolated mouse skeletal muscle fibres

Background Sarcopenia, the progressive decline in skeletal muscle mass and function with age, is a debilitating condition. It leads to inactivity, falls, and loss of independence. Despite this, its cause(s) and the underlying mechanism(s) are still poorly understood. Methods In this study, small skeletal muscle fibre bundles isolated from the extensor digitorum longus (a fast-twitch muscle) and the soleus (a slow-twitch muscle) of adult mice of different ages (range 100–900 days old) were used to investigate the effects of ageing and dihydrotestosterone (DHT) treatment on protein synthesis as well as the expression and function of two amino acid transporters; the sodium-coupled neutral amino acid transporter (SNAT) 2, and the sodium-independent L-type amino-acid transporter (LAT) 2. Results At all ages investigated, protein synthesis was always higher in the slow-twitch than in the fast-twitch muscle fibres and decreased with age in both fibre types. However, the decline was greater in the fast-twitch than in the slow-twitch fibres and was accompanied by a reduction in the expression of SNAT2 and LAT2 at the protein level. Again, the decrease in the expression of the amino acid transporters was greater in the fast-twitch than in the slow-twitch fibres. In contrast, ageing had no effect on SNAT2 and LAT2 expressions at the mRNA level. Treating the muscle fibre bundles with physiological concentrations (~2 nM) of DHT for 1 h completely reversed the effects of ageing on protein synthesis and the expression of SNAT2 and LAT2 protein in both fibre types. Conclusion From the observations that ageing is accompanied by a reduction in protein synthesis and transporter expression and that these effects are reversed by DHT treatment, we conclude that sarcopenia arises from an age-dependent reduction in protein synthesis caused, in part, by the lack of or by the low bioavailability of the male sex steroid, DHT