Guinea pig fetus does not change its presentation during second half of gestation

Objectives: The aims of this paper are: 1. To investigate spontaneous changes in fetal presentation during the second half of gestation in guinea pig fetus, 2. to observe provoked changes of fetal presentation, by passive positioning fetus into an upside-down position and “sitting” position. Eight fetuses from singleton pregnancies were included. Experimental design: Ultrasound examinations (Toshiba Nemio SSA-550A apparatus) were started on the 26th day of gestation (GD). Each fetus was examined 2-3 times in each 5-day interval until the end of gestation. First the spontaneous orientation of fetus was determined by tracking along the longitudinal and transversal axes of the fetus with the ultrasound probe. Then the fetus was brought into a head-down position relative to gravity for 5 minutes. The examination was repeated with the fetus in the head-up position. Results: In the period from the 26th – 30th GD in 7 of 21 observations spontaneous changes of presentation were observed. From the 31st GD all 133 observations were negative regarding spontaneous changes of presentation and situs. The chi-squared test showed that difference in spontaneous changes of presentation and situs before versus after 30th day of gestation had a statistical significance (χ² = 25.16 p 0.05). Fetuses were brought into a head-down and head-up 154 times. In none of these attempts did a fetus change presentation during the five minutes of observation. Conclusion: Guinea pig fetuses do not spontaneously or at provocation change presentation after 30th GD

Short-term health effects of air quality changes during the COVID‑19 pandemic in the City of Novi Sad, the Republic of Serbia

ObjectivesThe objective of this research is to determine the change in outdoor air quality during the COVID‑19 related state of emergency resulting in a lockdown and the potential health benefits for the urban population.Material and MethodsDuring 53 days of the COVID‑19 related state of emergency with a lockdown (March 15–May 6, 2020) in the Republic of Serbia, as well as in the corresponding periods of 2018 and 2019, data on the daily sulfur dioxide (SO2), nitrogen dioxide (NO2), ground-level ozone (O3) and particulate matter (PM10 and PM2.5) concentrations were analyzed. The total mortality data were analyzed to estimate the impact of the COVID‑19 related lockdown measures on the burden of health in a given population, attributed to the outdoor air quality in the City of Novi Sad, using AirQ+ software.ResultsThe average daily concentrations of PM2.5, NO2, PM10 and SO2 were reduced by 35%, 34%, 23% and 18%, respectively. In contrast, the average daily concentration of O3 increased by 8%, even if the primary precursors were reducing, thus representing a challenge for air quality management. In the City of Novi Sad, a reduction in the average daily PM2.5 concentration of 11.23 μg/m³ was significant, which resulted in a quantified number of avoided deaths.ConclusionsAir pollution in the City of Novi Sad had a chance to be improved due to some preventive measures related to the infectious disease (the COVID‑19 related lockdown), which in turn was the mitigation measure to air pollution with positive public health effects. The confirmed positive effects of the improved air quality on public health could also include raising collective resistance to mass non-communicable and infectious diseases such as COVID‑19 and reducing economic costs