RESUMO
Free radicals, products of oxidative processes, induce cellular damage linked to diseases like Parkinson's and diabetes due to increased reactive oxygen species (ROS) levels. Catalase, crucial for scavenging ROS, emerges as a therapeutic agent against ailments including atherosclerosis and tumor progression. Its primary function involves breaking down hydrogen peroxide into water and oxygen. Research on catalase-drug interactions reveals structural changes under specific conditions, affecting its activity and cellular antioxidant balance, highlighting its pivotal role in defending against oxidative stress-related diseases. Hence, targeting catalase is considered an effective strategy for controlling ROS-induced cellular damage. This study investigates the interaction between bovine liver catalase and glipizide using spectroscopic and computational methods. It also explores glipizide's effect on catalase activity. More than 20% inhibition of catalase enzymatic activity was recorded in the presence of 50 µM glipizide. To investigate the inhibition of catalase activity by glipizide, we performed a series of binding studies. Glipizide was found to form a complex with catalase with moderate affinity and binding constant in the range of 3.822 to 5.063 × 104 M-1. The binding was spontaneous and entropically favourable. The α-helical content of catalase increased from 24.04 to 29.53% upon glipizide complexation. Glipizide binding does not alter the local environment surrounding the tyrosine residues while a notable decrease in polarity around the tryptophan residues of catalase was recorded. Glipizide interacted with numerous active site residues of catalase including His361, Tyr357, Ala332, Asn147, Arg71, and Thr360. Molecular simulations revealed that the catalase-glipizide complex remained relatively stable in an aqueous environment. The binding of glipizide had a negligible effect on the secondary structure of catalase, and hydrogen bonds persisted consistently throughout the trajectory. These results could aid in the development of glipizide as a potent catalase inhibitor, potentially reducing the impact of reactive oxygen species (ROS) in the human body.
RESUMO
Background: The continuous spreading of the respiratory coronavirus disease, COVID-19, has been a threat to global health, especially among those fighting directly against it. Nurses who work in critical care have reported very high levels of stress during these extreme circumstances. It is very important to measure the level of stress and resilience among these nurses in order to diminish further psychological distress. This study aims to assess the levels of perceived stress and resilience among critical care nurses. Methodology: In this correlational cross-sectional study, critical care nurses (n = 139) were recruited by gatekeepers in a governmental university hospital in Riyadh City between 12 March and 8 April 2021 to complete an online questionnaire. The measurement tools used in this study were the Connor-Davidson Resilience Scale 10 (CD-RISC-10) and the Perceived Stress Scale of COVID-19 (PSS-10 items). Data were analyzed using a descriptive and inferential analysis to calculate frequencies to determine the distribution of stress and resilience, and multiple regression was applied to assess the relationship between them. Results: One hundred and thirty-nine critical care nurse (64%) responded. The perceived levels of stress reported were: no stress (8%; n = 12), mild stress (14%; n = 21), moderate stress (38%; n = 55), high stress (22%; n = 32), and severe stress (18%; n = 26). The levels of resilience reported were: very low (8%; n = 11), low (18%; n = 26), moderate (42%; n = 62), and high (32%; n = 47). The level of stress and resilience reported by the majority of critical care nurses was moderate; there was no significant correlation between COVID-19-related stress and resilience among the critical care nurses. Severe levels of stress were mostly reported among critical care nurses working in the NICU and high levels of stress were reported among those working in the emergency department. The nurses reported being highly confident that they were able to handle personal epidemic related problems with a mean score of 2.36. This reflects having a high level of resilience (42%; n = 62) and was significantly associated with years of experience as a nurse (p < 0.0027). Conclusion: Although COVID-19 cases had declined significantly during the study period in Saudi Arabia, the majority of nurses were still experiencing moderate to high levels of stress about the epidemic, but were, at the same time, moderately resilient. Continued monitoring of the stress levels of this high-risk group is highly essential. Conducting more research is needed to measure the effectiveness of psychosocial support interventions.
