Effect of COVID-19-restrictive measures on ambient particulate matter pollution in Yangon, Myanmar.

BACKGROUND: Particulate matter (PM) is recognized as the most harmful air pollutant to the human health. The Yangon city indeed suffers much from PM-related air pollution. Recent research has interestingly been focused on the novel subject of changes in the air quality associated with the restrictive measures in place during the current coronavirus disease-2019 (COVID-19) pandemic. The first case of COVID-19 in Myanmar was diagnosed on March 23, 2020. In this article, we report on our attempt to evaluate any effects of the COVID-19-restrictive measures on the ambient PM pollution in Yangon. METHODS: We measured the PM concentrations every second for 1 week on four occasions at three study sites with different characteristics; the first occasion was before the start of the COVID-19 pandemic and the remaining three occasions were while the COVID-19-restrictive measures were in place, including Stay-At-Home and Work-From-Home orders. The Pocket PM2.5 Sensor [PRO] designed by the National Institute for Environmental Studies (NIES), Japan, in cooperation with Yaguchi Electric Co., Ltd., (Miyagi, Japan) was used for the measurement of the ambient PM2.5 and PM10 concentrations. RESULTS: The results showed that there was a significant reduction (P < 0.001) in both the PM2.5 and PM10 concentrations while the COVID-19-restrictive measures were in place as compared to the measured values prior to the pandemic. The city experienced a profound improvement in the PM-related air quality from the "unhealthy" category prior to the onset of the COVID-19 pandemic to the "good" category during the pandemic, when the restrictive measures were in place. The percent changes in the PM concentrations varied among the three study sites, with the highest percent reduction noted in a semi-commercial crowded area (84.8% for PM2.5; 88.6% for PM10) and the lowest percent reduction noted in a residential quiet area (15.6% for PM2.5; 12.0% for PM10); the percent reductions also varied among the different occasions during the COVID-19 pandemic that the measurements were made. CONCLUSIONS: We concluded that the restrictive measures which were in effect to combat the COVID-19 pandemic had a positive impact on the ambient PM concentrations. The changes in the PM concentrations are considered to be largely attributable to reduction in anthropogenic emissions as a result of the restrictive measures, although seasonal influences could also have contributed in part. Thus, frequent, once- or twice-weekly Stay-At-Home or Telework campaigns, may be feasible measures to reduce PM-related air pollution. When devising such an action plan, it would be essential to raise the awareness of public about the health risks associated with air pollution and create a social environment in which Telework can be carried out, in order to ensure active compliance by the citizens.

Improvement of GPS-attached Pocket PM2.5 Measuring Device for Personal Exposure Assessment.

Assessment of personal exposure to particulate matter with an aerodynamic diameter less than or 2.5 µm (PM2.5) is necessary to study the association between PM exposure and health risk. Development of a personal PM2.5 sensor or device is required for the evaluation of individual exposure level. In this study, we aimed to develop a small-sized, lightweight sensor with a global positioning system (GPS) attached that can measure PM2.5 and PM10 every second to assess continuous personal exposure levels. The participants in this study were apparently healthy housewives (n = 15) and university female teaching staff (n = 15) who live in a high PM2.5 area, Yangon, Myanmar. The average PM2.5 exposure levels during 24 h were 16.1 ± 10.0 µg/m3 in the housewives and 15.8 ± 4.0 µg/m3 in the university female teaching staff. The university female teaching staff showed high exposure concentrations during commuting hours, and had stable, relatively low concentrations at work, whereas the housewives showed short-term high exposure peaks due to differences in their lifestyles. This is the first study to show that a GPS-attached standalone PM2.5 and PM10 Sensor [PRO] can be successfully used for mobile sensing, easy use, continuous measurement, and rapid data analysis.

Deficiency of the circadian clock gene Rev-erbα induces mood disorder-like behaviours and dysregulation of the serotonergic system in mice.

Mood disorders such as depression, anxiety, and bipolar disorder are highly associated with disrupted daily rhythms of activity, which are often observed in shift work and sleep disturbance in humans. Recent studies have proposed the REV-ERBα protein as a key circadian nuclear receptor that links behavioural rhythms to mood regulation. However, how the Rev-erbα gene participates in the regulation of mood remains poorly understood. Here, we show that the regulation of the serotonergic (5-HTergic) system, which plays a central role in stress-induced mood behaviours, is markedly disrupted in Rev-erbα-/- mice. Rev-erbα-/- mice exhibit both negative and positive behavioural phenotypes, including anxiety-like and mania-like behaviours, when subjected to a stressful environment. Importantly, Rev-erbα-/- mice show a significant decrease in the expression of a gene that encodes the rate-limiting enzyme of serotonin (5-HT) synthesis in the raphe nuclei (RN). In addition, 5-HT levels in Rev-erbα-/- mice are significantly reduced in the prefrontal cortex, which receives strong inputs from the RN and controls stress-related behaviours. Our findings indicate that Rev-erbα plays an important role in controlling the 5-HTergic system and thus regulates mood and behaviour.

Indoor Formaldehyde Concentration, Personal Formaldehyde Exposure and Clinical Symptoms during Anatomy Dissection Sessions, University of Medicine 1, Yangon.

The formaldehyde (FA) embalming method, the world's most common protocol for the fixation of cadavers, has been consistently used in medical universities in Myanmar. This study was designed to examine the indoor FA concentrations in anatomy dissection rooms, an exposed site, and lecture theater, an unexposed control site, and to access personal exposure levels of FA and clinical symptoms of medical students and instructors. In total, 208 second year medical students (1/2019 batch) and 18 instructors from Department of Anatomy, University of Medicine 1, participated. Thirteen dissection sessions were investigated from February 2019 to January 2020. Diffusive sampling devices were used as air samplers and high-performance liquid chromatography was used for measurement of FA. Average indoor FA concentration of four dissection rooms was 0.43 (0.09-1.22) ppm and all dissection rooms showed indoor concentrations above the occupational exposure limits and short-term exposure limit for general population. Personal FA exposure values were higher than indoor FA concentrations and the instructors (0.68, 0.04-2.11 ppm) had higher exposure than the students (0.44, 0.06-1.72 ppm). Unpleasant odor, eye and nose irritations and inability to concentrate were frequently reported FA-related symptoms, and the students were found to have significantly higher risks (p < 0.05) of having these symptoms during the dissection sessions than during lecture.

Impact of heart-specific disruption of the circadian clock on systemic glucose metabolism in mice.

The daily rhythm of glucose metabolism is governed by the circadian clock, which consists of cell-autonomous clock machineries residing in nearly every tissue in the body. Disruption of these clock machineries either environmentally or genetically induces the dysregulation of glucose metabolism. Although the roles of clock machineries in the regulation of glucose metabolism have been uncovered in major metabolic tissues, such as the pancreas, liver, and skeletal muscle, it remains unknown whether clock function in non-major metabolic tissues also affects systemic glucose metabolism. Here, we tested the hypothesis that disruption of the clock machinery in the heart might also affect systemic glucose metabolism, because heart function is known to be associated with glucose tolerance. We examined glucose and insulin tolerance as well as heart phenotypes in mice with heart-specific deletion of Bmal1, a core clock gene. Bmal1 deletion in the heart not only decreased heart function but also led to systemic insulin resistance. Moreover, hyperglycemia was induced with age. Furthermore, heart-specific Bmal1-deficient mice exhibited decreased insulin-induced phosphorylation of Akt in the liver, thus indicating that Bmal1 deletion in the heart causes hepatic insulin resistance. Our findings revealed an unexpected effect of the function of clock machinery in a non-major metabolic tissue, the heart, on systemic glucose metabolism in mammals.