Examining the role of community health workers amid extreme weather events in low- and middle-income countries: a scoping review.

OBJECTIVES: The increased frequency and severity of extreme weather events (EWEs) have underscored the need to strengthen climate-resilient health systems and capacity. Community health workers (CHWs) are integral health systems actors with the potential to protect and improve population health in a changing climate. The aim of this review was to synthesize the literature on the roles of CHWs amid EWEs in low- and middle-income countries, the barriers and facilitators to implement these roles, and program supports to strengthen CHW capacity and health system functions. STUDY DESIGN: Scoping review. METHODS: Four academic databases and gray literature published between January 2000 and June 2023 were searched. Data were thematically analyzed using a deductive-inductive approach guided by the World Health Organization's (WHO's) Operational framework for building climate-resilient health systems. RESULTS: Thirty sources were included. Amid EWEs, CHW roles included: 1) delivery of diagnostic, treatment, and other clinical services; 2) support with access, utilization, or navigation of health services and/or referrals; 3) community education and health promotion; 4) data collection and health surveillance; 5) psychosocial supports; and 6) weather-related health emergency response. Facilitators and barriers to the provision of CHW supports amid EWEs were categorized within WHO's building blocks of health systems. Considerations for strengthening CHW programs to enhance climate-resilient health systems are also discussed. CONCLUSIONS: CHWs are uniquely positioned to provide health-related supports amid EWEs that extend to emergency preparedness and response to climate-health challenges. These efforts can contribute to the community and health systems resilience to climate change.

The chemical and kinetic consequences of the modification of papain by N-bromosuccinimide.

Nonactivated papain was treated with N-bromosuccinimide at pH 4.75. The N-bromosuccinimide-modified enzyme was characterized by (1) the change in absorbance at 280 nm, (2) amino acid analysis, (3) separate chemical determinations of tryptophan and tyrosine (4) difference spectroscopy, and (5) an N-terminal residue determination. It is concluded that N-bromosuccinimide in sevenfold molar excess oxidizes one tryptophan and two to three tyrosine residues per molecule of nonactivated papain, without causing peptide chain cleavage. Kinetic studies with several substrates and competitive peptide inhibitors were performed at pH6 using the N-bromosuccinimide-modified papain. In addition, the kinetics of the modified enzyme with the substrate alpha-N-benzoyl-L-arginine ethl ester were studied in the region of pH 3.5-9.0. All substrates (and inhibitors) test, with the exception of alpha-N-benzyoyl-L-arginine p-nitroanilide, displayed approximately a two fold decrease in both kcat and Km (or Ki), relative to the native enzyme. It is concluded that the key tryptophan residue which is probably Trp-177.

A graphical method for extracting rate constants from some enzyme-catalyzed reactions not monitored to completion.

A large number of enzyme-catalyzed reactions can be described by the equation y = At - B(1 - e-kt), where y is the amount of product formed, A is the slope of the linear portion of the curve, and B is a constant dependent on the mechanism of the reaction. The methods which are generally used to extract the rate constant, k, from absorbance-time data described by this equation require that the reaction be monitored for some 10 to 15 half-lives. We show herein that the rate constant k is readily obtained from a plot of (y'' - y') vs. (y' -y0) where y0, y', and y'' are the values of y at times t, t + deltat, and t + 2deltat. This graphical method is simple, reliable, and requires that the reaction be monitored for only three to five half-lives of the exponential phase of the reaction. We have used this method to measure the rate of activation of a mixed disulfide of papain and 2-nitro-5-mercaptobenzoic acid in the presence of substrate.