An Analysis of Water Used and Wasted at Operating Room (OR) Scrub Sinks and Call to Action for Reducing Water Waste.

OBJECTIVE: To model the volume of water used and wasted during wet scrubs at operating room (OR) scrub sinks and identify factors for reducing water waste. BACKGROUND: Wasteful consumption of water by US healthcare systems has not been well characterized. METHODS: This is a two-component observational study. The first was an observational study of handwashing practices and water usage at scrub sinks in the OR at a single medical center. The second component was a series of two anonymous surveys of surgeons and OR staff to assess hand scrub practices and perspectives. Data from both components were used to estimate the volume of water used and wasted annually at OR scrub sinks. RESULTS: The median total volume of water wasted at OR scrub sinks for 34,554 cases over one year is 337,595.6 L (interquartile range 139,010.0;911,210.5). This represents approximately 34.2% of the total volume of water usage associated with wet scrubs (i.e.,water used during scrubbing and wasted after the conclusion of the scrub). Other pertinent findings are that attending surgeons and OR staff perform water scrubs in 25.9% of cases; there are significant differences in scrub type preferences among OR users; the median volume of water wasted in a single wet scrub at timer-controlled sinks is 10 L; and significantly more water is wasted at timer-controlled sinks than knee-operated sinks. CONCLUSIONS: OR wet scrubs are a source of enormous water waste. We identified scrub sink characteristics and OR user beliefs and behaviors as modifiable factors for water waste reduction. We encourage all institutions and OR users to carefully examine their facility characteristics and practices to implement plans that will conserve water without compromising patient safety.

Small molecules disaggregate alpha-synuclein and prevent seeding from patient brain-derived fibrils.

The amyloid aggregation of alpha-synuclein within the brain is associated with the pathogenesis of Parkinson's disease (PD) and other related synucleinopathies, including multiple system atrophy (MSA). Alpha-synuclein aggregates are a major therapeutic target for treatment of these diseases. We identify two small molecules capable of disassembling preformed alpha-synuclein fibrils. The compounds, termed CNS-11 and CNS-11g, disaggregate recombinant alpha-synuclein fibrils in vitro, prevent the intracellular seeded aggregation of alpha-synuclein fibrils, and mitigate alpha-synuclein fibril cytotoxicity in neuronal cells. Furthermore, we demonstrate that both compounds disassemble fibrils extracted from MSA patient brains and prevent their intracellular seeding. They also reduce in vivo alpha-synuclein aggregates in C. elegans. Both compounds also penetrate brain tissue in mice. A molecular dynamics-based computational model suggests the compounds may exert their disaggregating effects on the N terminus of the fibril core. These compounds appear to be promising therapeutic leads for targeting alpha-synuclein for the treatment of synucleinopathies.

Structure-based discovery of small molecules that disaggregate Alzheimer's disease tissue derived tau fibrils in vitro.

Alzheimer's disease (AD) is the consequence of neuronal death and brain atrophy associated with the aggregation of protein tau into fibrils. Thus disaggregation of tau fibrils could be a therapeutic approach to AD. The small molecule EGCG, abundant in green tea, has long been known to disaggregate tau and other amyloid fibrils, but EGCG has poor drug-like properties, failing to fully penetrate the brain. Here we have cryogenically trapped an intermediate of brain-extracted tau fibrils on the kinetic pathway to EGCG-induced disaggregation and have determined its cryoEM structure. The structure reveals that EGCG molecules stack in polar clefts between the paired helical protofilaments that pathologically define AD. Treating the EGCG binding position as a pharmacophore, we computationally screened thousands of drug-like compounds for compatibility for the pharmacophore, discovering several that experimentally disaggregate brain-derived tau fibrils in vitro. This work suggests the potential of structure-based, small-molecule drug discovery for amyloid diseases.

De novo designed protein inhibitors of amyloid aggregation and seeding.

Neurodegenerative diseases are characterized by the pathologic accumulation of aggregated proteins. Known as amyloid, these fibrillar aggregates include proteins such as tau and amyloid-ß (Aß) in Alzheimer's disease (AD) and alpha-synuclein (αSyn) in Parkinson's disease (PD). The development and spread of amyloid fibrils within the brain correlates with disease onset and progression, and inhibiting amyloid formation is a possible route toward therapeutic development. Recent advances have enabled the determination of amyloid fibril structures to atomic-level resolution, improving the possibility of structure-based inhibitor design. In this work, we use these amyloid structures to design inhibitors that bind to the ends of fibrils, "capping" them so as to prevent further growth. Using de novo protein design, we develop a library of miniprotein inhibitors of 35 to 48 residues that target the amyloid structures of tau, Aß, and αSyn. Biophysical characterization of top in silico designed inhibitors shows they form stable folds, have no sequence similarity to naturally occurring proteins, and specifically prevent the aggregation of their targeted amyloid-prone proteins in vitro. The inhibitors also prevent the seeded aggregation and toxicity of fibrils in cells. In vivo evaluation reveals their ability to reduce aggregation and rescue motor deficits in Caenorhabditis elegans models of PD and AD.

Identifying amyloid-related diseases by mapping mutations in low-complexity protein domains to pathologies.

Proteins including FUS, hnRNPA2, and TDP-43 reversibly aggregate into amyloid-like fibrils through interactions of their low-complexity domains (LCDs). Mutations in LCDs can promote irreversible amyloid aggregation and disease. We introduce a computational approach to identify mutations in LCDs of disease-associated proteins predicted to increase propensity for amyloid aggregation. We identify several disease-related mutations in the intermediate filament protein keratin-8 (KRT8). Atomic structures of wild-type and mutant KRT8 segments confirm the transition to a pleated strand capable of amyloid formation. Biochemical analysis reveals KRT8 forms amyloid aggregates, and the identified mutations promote aggregation. Aggregated KRT8 is found in Mallory-Denk bodies, observed in hepatocytes of livers with alcoholic steatohepatitis (ASH). We demonstrate that ethanol promotes KRT8 aggregation, and KRT8 amyloids co-crystallize with alcohol. Lastly, KRT8 aggregation can be seeded by liver extract from people with ASH, consistent with the amyloid nature of KRT8 aggregates and the classification of ASH as an amyloid-related condition.

Extended ß-Strands Contribute to Reversible Amyloid Formation.

The assembly of proteins into fibrillar amyloid structures was once considered to be pathologic and essentially irreversible. Recent studies reveal amyloid-like structures that form reversibly, derived from protein low-complexity domains which function in cellular metabolism. Here, by comparing atomic-level structures of reversible and irreversible amyloid fibrils, we find that the ß-sheets of reversible fibrils are enriched in flattened (as opposed to pleated) ß-sheets formed by stacking of extended ß-strands. Quantum mechanical calculations show that glycine residues favor extended ß-strands which may be stabilized by intraresidue interactions between the amide proton and the carbonyl oxygen, known as C5 hydrogen-bonds. Larger residue side chains favor shorter strands and pleated sheets. These findings highlight a structural element that may regulate reversible amyloid assembly.