COVID-19 Infection in Pregnancy: A Review.

Coronavirus disease 2019 (COVID-19), which is a highly contagious viral illness caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has had a catastrophic effect on the world's demographics, resulting in more than 3.8 million deaths worldwide and establishing itself as the most serious global health crisis since the 1918 influenza pandemic. Several questions remain unanswered regarding the effects of COVID-19 disease during pregnancy. Although most infections are mild in high-risk populations, the severe disease frequently leads to intubation, intensive care unit admission, and, in some cases, death. Hormonal and physiological changes in the immune and respiratory systems, cardiovascular function, and coagulation may affect the progression of COVID-19 disease in pregnancy. However, the consequences of coronavirus infection on implantation, fetal growth and development, labor, and newborn health have yet to be determined, and, consequently, a coordinated global effort is needed in this respect. Principles of management concerning COVID-19 in pregnancy include early isolation, aggressive infection control procedures, oxygen therapy, avoidance of fluid overload, consideration of empiric antibiotics (secondary to bacterial infection risk), laboratory testing for the virus and co-infection, fetal and uterine contraction monitoring, prevention, and / or treatment of thromboembolism early mechanical ventilation for progressive respiratory failure, individualized delivery planning, and a team-based approach with multispecialty consultations. This review focuses on COVID-19 during pregnancy, its management, and the area where further investigations are needed to reduce the risk to mothers and their newborns.

Isotopic evidence suggests different initial reaction mechanisms for anaerobic benzene biodegradation.

The initial metabolic reactions for anaerobic benzene biodegradation remain uncharacterized. Isotopic data for carbon and hydrogen fractionation from nitrate-reducing, sulfate-reducing, and methanogenic benzene-degrading enrichment cultures and phylogenic information were used to investigate the initial reaction step in anaerobic benzene biodegradation. Dual parameter plots of carbon and hydrogen isotopic data (deltadelta2H/ deltadelta13C) from each culture were linear, suggesting a consistent reaction mechanism as degradation proceeded. Methanogenic and sulfate-reducing cultures showed consistently higher slopes (m = 29 +/- 2) compared to nitrate-reducing cultures (m = 13 +/- 2) providing evidence for different initial reaction mechanisms. Phylogenetic analyses confirmed that culture conditions were strictly anaerobic, precluding any involvement of molecular oxygen in the observed differences. Using published kinetic data, we explored the possibility of attributing such slopes to reaction mechanisms. The higher slopes found under methanogenic and sulfate-reducing conditions suggest against an alkylation mechanism for these cultures. Observed differences between the methanogenic and nitrate-reducing cultures may not represent distinct reactions of different bonds, but rather subtle differences in relative reaction kinetics. Additional mechanistic conclusions could not be made because kinetic isotope effect data for carboxylation and other putative mechanisms are not available.