Cushing's Syndrome: Rapid Evidence Review.

Cushing's syndrome is a rare, multisystemic disease caused by chronic exposure to supraphysiologic levels of cortisol. Prolonged hypercortisolism is associated with significant multisystem morbidity and mortality and decreased quality of life. Diagnosis of Cushing's syndrome is often delayed by several years due to its insidiously progressive course, diverse clinical presentation, overlap of symptoms with many common conditions, and testing complexity. Exogenous glucocorticoid use must be excluded as the primary etiology. Excessive endogenous cortisol production can be caused by an overproduction of adrenocorticotropic hormone (ACTH) through pituitary tumors or ectopic sources (ACTH-dependent cases), or it can be caused by autonomous cortisol overproduction by the adrenal glands (ACTH-independent cases). The recommended diagnostic approach includes appropriate screening, confirmation of hypercortisolism, and determination of etiology. First-line treatment is surgical removal of the source of cortisol overproduction. Lifelong posttherapy monitoring is required to treat comorbidities and detect recurrence.

Investigations of microbial adaptation to singular, binary, and fully formulated quaternary ammonium compounds.

The study was conducted to inform risk assessments concerning microbial exposure to quaternary ammonium biocides (QUATs) by investigating their effects on 10 microbial strains of hygiene relevance. Biocides were divided into three categories: simple aqueous solutions, biocide mixtures, and formulated biocides. Organisms were grown in the presence of biocides for 10 generations and then subsequently for another 10 generations in biocide-free media. Control organisms were passaged 20 times in biocide-free media. Strains were then assessed for biocide and antibiotic susceptibility, changes in growth dynamics, and single nucleotide polymorphisms (SNPs). Biocide mixtures demonstrated greater antimicrobial potency than singular and formulated biocides. Susceptibility changes of under twofold were observed for all biocides tested. Susceptibility decreased significantly for organisms passaged with singular biocides (1.29- to 4.35-fold) and biocide mixtures (1.4- to 1.5-fold), but not for formulated biocides (1.3- to 1.84-fold) compared to controls. Antibiotic susceptibility both increased and decreased in passaged organisms, with heightened susceptibility occurring more frequently in the singular biocide group. Changes in susceptibility and growth dynamics were similar in the passaged and unexposed controls for fitness measures of adapted bacteria; there were no significant differences between biocide groups, but significantly lower generation and doubling times in organisms exposed to singular biocides. Similar frequencies in SNPs occurred for the three biocide groups and unexposed controls. While some adaptations occurred, particularly with singular biocides, the impact on antibiotic resistance and genomic mutations was limited. These findings suggest that the use of formulated QUATs may pose a comparatively lower risk for antimicrobial resistance.IMPORTANCEBiocides are used globally to control microbial growth and effective assessment of the risks and benefits of their use is therefore a high priority. Much of the data used to assess risk has been based on sub-lethal exposure of bacteria to singular biocides in simple aqueous solutions. This work builds on limited prior realism-based studies to demonstrate enhanced potency in biocidal mixtures; the mitigation of resistance selection by formulations and inconsistent cross-resistance effects with both increases and decreases in susceptibility for a wide range of antibiotics. These data can be used to better inform risk assessments of biocide deployment.

Sex-specific variation in species interactions matters in ecological communities.

Understanding how natural communities and ecosystems are structured and respond to anthropogenic pressures in a rapidly changing world is key to successful management and conservation. A fundamental but often overlooked biological characteristic of organisms is sex. Sex-based responses are often considered when conducting studies at organismal and population levels, but are rarely investigated in community ecology. Focusing on kelp forests as a model system, and through a review of other marine and terrestrial ecosystems, we found evidence of widespread sex-based variation in species interactions. Sex-based variation in species interactions is expected to affect ecosystem structure and functioning via multiple trophic and nontrophic pathways. Understanding the drivers and consequences of sex-based variation in species interactions can inform more effective management and restoration.

Collective peroxide detoxification determines microbial mutation rate plasticity in E. coli.

Mutagenesis is responsive to many environmental factors. Evolution therefore depends on the environment not only for selection but also in determining the variation available in a population. One such environmental dependency is the inverse relationship between mutation rates and population density in many microbial species. Here, we determine the mechanism responsible for this mutation rate plasticity. Using dynamical computational modelling and in culture mutation rate estimation, we show that the negative relationship between mutation rate and population density arises from the collective ability of microbial populations to control concentrations of hydrogen peroxide. We demonstrate a loss of this density-associated mutation rate plasticity (DAMP) when Escherichia coli populations are deficient in the degradation of hydrogen peroxide. We further show that the reduction in mutation rate in denser populations is restored in peroxide degradation-deficient cells by the presence of wild-type cells in a mixed population. Together, these model-guided experiments provide a mechanistic explanation for DAMP, applicable across all domains of life, and frames mutation rate as a dynamic trait shaped by microbial community composition.

Adaptation at the Extremes of Life: Experimental Evolution with the Extremophile Archaeon Sulfolobus acidocaldarius.

The archaeon Sulfolobus acidocaldarius has emerged as a promising thermophilic model system. Investigating how thermophiles adapt to changing temperatures is a key requirement, not only for understanding fundamental evolutionary processes but also for developing S. acidocaldarius as a chassis for bioengineering. One major obstacle to conducting experimental evolution with thermophiles is the expense of equipment maintenance and energy usage of traditional incubators for high-temperature growth. To address this challenge, a comprehensive experimental protocol for conducting experimental evolution in S. acidocaldarius is presented, utilizing low-cost and energy-efficient bench-top thermomixers. The protocol involves a batch culture technique with relatively small volumes (1.5 mL), enabling tracking of adaptation in multiple independent lineages. This method is easily scalable through the use of additional thermomixers. Such an approach increases the accessibility of S. acidocaldarius as a model system by reducing both initial investment and ongoing costs associated with experimental investigations. Moreover, the technique is transferable to other microbial systems for exploring adaptation to diverse environmental conditions.

Correction: Clinical reasoning education in the clerkship years: A cross-disciplinary national needs assessment.

[This corrects the article DOI: 10.1371/journal.pone.0273250.].

Discovery, Multiparametric Optimization, and Solid-State Driven Identification of CHF-6550, a Novel Soft Dual Pharmacology Muscarinic Antagonist and ß2 Agonist (MABA) for the Inhaled Treatment of Respiratory Diseases.

Clinical guidelines for COPD and asthma recommend inhaled ß-adrenergic agonists, muscarinic antagonists, and, for frequent exacerbators, inhaled corticosteroids, with the challenge of combining them into a single device. The MABA (muscarinic antagonist and ß2 agonist) concept has the potential to simplify this complexity while increasing the efficacy of both pharmacologies. In this article, we report the outcome of our solid-state driven back-up program that led to the discovery of the MABA compound CHF-6550. A soft drug approach was applied, aiming at high plasma protein binding and high hepatic clearance, concurrently with an early stage assessment of crystallinity through a dedicated experimental workflow. A new chemotype was identified, the diphenyl hydroxyacetic esters, able to generate crystalline material. Among this class, CHF-6550 demonstrated in vivo efficacy, suitability for dry powder inhaler development, favorable pharmacokinetics, and safety in preclinical settings and was selected as a back-up candidate, fulfilling the desired pharmacological and solid-state profile.

Environmental and genetic influence on the rate and spectrum of spontaneous mutations in Escherichia coli.

Spontaneous mutations are the ultimate source of novel genetic variation on which evolution operates. Although mutation rate is often discussed as a single parameter in evolution, it comprises multiple distinct types of changes at the level of DNA. Moreover, the rates of these distinct changes can be independently influenced by genomic background and environmental conditions. Using fluctuation tests, we characterized the spectrum of spontaneous mutations in Escherichia coli grown in low and high glucose environments. These conditions are known to affect the rate of spontaneous mutation in wild-type MG1655, but not in a ΔluxS deletant strain - a gene with roles in both quorum sensing and the recycling of methylation products used in E. coli's DNA repair process. We find an increase in AT>GC transitions in the low glucose environment, suggesting that processes relating to the production or repair of this mutation could drive the response of overall mutation rate to glucose concentration. Interestingly, this increase in AT>GC transitions is maintained by the glucose non-responsive ΔluxS deletant. Instead, an elevated rate of GC>TA transversions, more common in a high glucose environment, leads to a net non-responsiveness of overall mutation rate for this strain. Our results show how relatively subtle changes, such as the concentration of a carbon substrate or loss of a regulatory gene, can substantially influence the amount and nature of genetic variation available to selection.

Cost-effectiveness of nivolumab versus surveillance for the adjuvant treatment of patients with urothelial carcinoma who are at high risk of recurrence: a US payer perspective.

AIM: To evaluate the cost-effectiveness of adjuvant nivolumab compared with surveillance for the treatment of patients with high-risk muscle-invasive urothelial carcinoma (MIUC) after radical resection from a US healthcare payer perspective and to investigate the impact of alternative modeling approaches on the cost-effectiveness results. MATERIAL AND METHODS: A four-state, semi-Markov model consisting of disease free, local recurrence, distant recurrence, and death health states was developed to investigate the cost-effectiveness of nivolumab compared with surveillance over a 30-year time horizon. The model used data from the randomized CheckMate 274 trial (NCT02632409) and published literature to inform transitions among health states, and inputs on cost, utility, adverse event, and disease management. Scenario analyses were conducted to investigate the impact of model structure and key assumptions on the results. One-way deterministic and probabilistic sensitivity analysis were conducted to investigate the robustness of the results. RESULTS: Total expected costs were higher with nivolumab ($162,278) compared with surveillance ($63,027). Nivolumab was associated with improved survival (1.61 life-years gained compared with surveillance) and an incremental gain of 0.98 quality-adjusted life-years (QALYs). Although total treatment costs were higher for nivolumab, cost offsets were observed because of delayed or avoided recurrences and deaths experienced with nivolumab compared with observation. The incremental cost-effectiveness and cost-utility ratios were $61,462/life-year and $100,930/QALY. LIMITATIONS: At the time of analysis, CheckMate 274 had limited follow-up on disease-free survival and no overall survival data. The limited evidence necessitated assumptions on modeling survival after each type of recurrence. CONCLUSIONS: Nivolumab is estimated to be a life-extending and cost-effective option for adjuvant treatment of MIUC for patients who are at high risk of recurrence after undergoing radical resection in the United States. Using a threshold of $150,000/QALY, the cost-effectiveness conclusions remained consistent across the scenario and sensitivity analyses conducted.

Impaired performance of rapid grip in people with Parkinson's disease and motor segmentation.

Bradykinesia, or slow movement, is a defining symptom of Parkinson's disease (PD), but the underlying neuromechanical deficits that lead to this slowness remain unclear. People with PD often have impaired rates of motor output accompanied by disruptions in neuromuscular excitation, causing abnormal, segmented, force-time curves. Previous investigations using single-joint models indicate that agonist electromyogram (EMG) silent periods cause motor segmentation. It is unknown whether motor segmentation is evident in more anatomically complex and ecologically important tasks, such as handgrip tasks. Aim 1 was to determine how handgrip rates of force change compare between people with PD and healthy young and older adults. Aim 2 was to determine whether motor segmentation is present in handgrip force and EMG measures in people with PD. Subjects performed rapid isometric handgrip pulses to 20-60% of their maximal voluntary contraction force while EMG was collected from the grip flexors and extensors. Dependent variables included the time to 90% peak force, the peak rate of force development, the duration above 90% of peak force, the number of segments in the force-time curve, the number of EMG bursts, time to relaxation from 90% of peak force, and the peak rate of force relaxation. People with PD had longer durations and lower rates of force change than young and older adults. Six of 22 people with PD had motor segmentation. People with PD had more EMG bursts compared to healthy adults and the number of EMG bursts covaried with the number of segments. Thus, control of rapid movement in Parkinson's disease can be studied using isometric handgrip. People with PD have impaired rate control compared to healthy adults and motor segmentation can be studied in handgrip.

Novel Colorimetric and Light Scatter Methods to Identify and Manage Peritoneal Dialysis-Associated Peritonitis at the Point-of-Care.

Introduction: Peritoneal dialysis (PD)-related peritonitis (PDRP) is a common cause of transfer to hemodialysis, patient morbidity, and is a risk factor for mortality. Associated patient anxiety can deter selection of PD for renal replacement therapy. Diagnosis relies on hospital laboratory tests; however, this might be achieved earlier if such information was available at the point-of-care (POC), thereby significantly improving outcomes. The presence of culturable microbes and the concentration of leukocytes in effluent both aid peritonitis diagnosis, as specified in the International Society for Peritoneal Dialysis (ISPD) diagnostic guidelines. Here, we report the development of 2 new methods providing such information in simple POC tests. Methods: One approach uses a tetrazolium-based chemical reporting system, primarily focused on detecting bacterial contamination and associated vancomycin-sensitivity. The second approach uses a novel forward light-scatter device (QuickCheck) to provide an instant quantitative cell count directly from PD patient effluent. Results: The tetrazolium approach detected and correctly distinguished laboratory isolates, taking 10 hours to provide non-quantitative results. We compared the technical performance of the light scatter leukocyte counting approach with spectrophotometry, hemocytometer counting and flow cytometry (Sysmex) using patient effluent samples. QuickCheck had high accuracy (94%) and was the most precise (coefficient of variation <4%), showing minimal bias, overall performing similarly to flow cytometry. Conclusion: These complementary new approaches provide a simple means to obtain information to assist diagnosis at the POC. The first provides antibiotic sensitivity following 10 hours incubation, whereas the second optical approach (QuickCheck), provides instant accurate total leukocyte count.

Challenges, considerations, and approaches for developing a cost-effectiveness model for the adjuvant treatment of muscle-invasive urothelial carcinoma: with a spotlight on nivolumab versus placebo.

AIMS: To present alternative approaches related to both structural assumptions and data sources for the development of a decision analytic model for evaluating the cost-effectiveness of adjuvant nivolumab compared with surveillance in patients with high-risk muscle-invasive urothelial carcinoma (MIUC) after radical resection. METHODS AND RESULTS: Alternative approaches related to both structural assumptions and data sources are presented to address challenges and data gaps, as well as discussion of strengths and limitations of each approach. Specifically, challenges and considerations related to the following are presented: (1) selection of a modeling approach (partitioned survival model or state transition model) given the available evidence, (2) choice of health state structure (three- or four-state) to model disease progression and subsequent therapy, (3) modeling of outcomes from subsequent therapy using tunnel states to account for time-dependent transition probabilities or absorbing health states with one-off costs and outcomes applied, and (4) methods for modeling health-state transitions in a setting where treatment has curative intent and available survival data are immature. CONCLUSIONS: Multiple considerations must be taken into account when developing an economic model for new, emerging oncology treatments in early lines of therapy, all of which can affect the model's overall ability to estimate (quality-adjusted) survival benefits over a lifetime horizon. This paper identifies a series of key structural and analytic considerations regarding modeling of nivolumab treatment in the adjuvant MIUC setting. Several alternative approaches with regard to structure and data have been included in a flexible cost-effectiveness model so the impact of the alternative approaches on model results can be explored. The impact of these alternative approaches on cost-effectiveness results are presented in a companion article. Our findings may also help inform the development of future models for other treatments and settings in early-stage cancer.

Large-scale molecular dynamics simulations of bubble collapse in water: Effects of system size, water model, and nitrogen.

Molecular dynamics simulations in the microcanonical ensemble are performed to study the collapse of a bubble in liquid water using the single-site mW and the four-site TIP4P/2005 water models. To study system size effects, simulations for pure water systems are performed using periodically replicated simulation boxes with linear dimensions, L, ranging from 32 to 512 nm with the largest systems containing 8.7 × 106 and 4.5 × 109 molecules for the TIP4P/2005 and mW water models, respectively. The computationally more efficient mW water model allows us to reach converging behavior when the bubble dynamics results are plotted in reduced units, and the limiting behavior can be obtained through linear extrapolation in L-1. Qualitative differences are observed between simulations with the mW and TIP4P/2005 water models, but they can be explained by the models' differences in predicted viscosity and surface tension. Although bubble collapse occurs on time scales of only hundreds of picoseconds, the system sizes used here are sufficiently large to obtain bubble dynamics consistent with the Rayleigh-Plesset equation when using the models' thermophysical properties as input. For the conditions explored here, extreme heating of the interfacial water molecules near the time of collapse is observed for the larger mW water systems (but the model underpredicts the viscosity), whereas heating is less pronounced for the TIP4P/2005 water systems because its larger viscosity contribution slows the collapse dynamics. The presence of nitrogen within the bubble only starts to affect bubble dynamics near the very end of the initial collapse, leading to an incomplete collapse and strong rebound for the mW water model. Although nitrogen is non-condensable at 300 K, it becomes highly compressed and reaches a liquid-like density near the collapse point. We find that the dissolution of nitrogen is much slower than the movement of the collapsing water front, and the re-expansion of the dense nitrogen droplet gives rise to bubble rebound. The incompatibility of the collapse and dissolution time scales should be considered for continuum-scale modeling of bubble dynamics. We also confirm that the diffusion coefficient for dissolved nitrogen is insensitive to pressure as the liquid transitions from a compressed to a stretched state.

MBX: A many-body energy and force calculator for data-driven many-body simulations.

Many-Body eXpansion (MBX) is a C++ library that implements many-body potential energy functions (PEFs) within the "many-body energy" (MB-nrg) formalism. MB-nrg PEFs integrate an underlying polarizable model with explicit machine-learned representations of many-body interactions to achieve chemical accuracy from the gas to the condensed phases. MBX can be employed either as a stand-alone package or as an energy/force engine that can be integrated with generic software for molecular dynamics and Monte Carlo simulations. MBX is parallelized internally using Open Multi-Processing and can utilize Message Passing Interface when available in interfaced molecular simulation software. MBX enables classical and quantum molecular simulations with MB-nrg PEFs, as well as hybrid simulations that combine conventional force fields and MB-nrg PEFs, for diverse systems ranging from small gas-phase clusters to aqueous solutions and molecular fluids to biomolecular systems and metal-organic frameworks.

The Helicobacter pylori CagA oncoprotein disrupts Wnt/PCP signaling and promotes hyperproliferation of pyloric gland base cells.

Helicobacter pylori strains that deliver the oncoprotein CagA into gastric epithelial cells are the major etiologic agents of upper gastric diseases including gastric cancer. CagA promotes gastric carcinogenesis through interactions with multiple host proteins. Here, we show that CagA also disrupts Wnt-dependent planar cell polarity (Wnt/PCP), which orients cells within the plane of an epithelium and coordinates collective cell behaviors such as convergent extension to enable epithelial elongation during development. Ectopic expression of CagA in Xenopus laevis embryos impaired gastrulation, neural tube formation, and axis elongation, processes driven by convergent extension movements that depend on the Wnt/PCP pathway. Mice specifically expressing CagA in the stomach epithelium had longer pyloric glands and mislocalization of the tetraspanin proteins VANGL1 and VANGL2 (VANGL1/2), which are critical components of Wnt/PCP signaling. The increased pyloric gland length was due to hyperproliferation of cells at the gland base, where Lgr5+ stem and progenitor cells reside, and was associated with fewer differentiated enteroendocrine cells. In cultured human gastric epithelial cells, the N terminus of CagA interacted with the C-terminal cytoplasmic tails of VANGL1/2, which impaired Wnt/PCP signaling by inducing the mislocalization of VANGL1/2 from the plasma membrane to the cytoplasm. Thus, CagA may contribute to the development of gastric cancer by subverting a Wnt/PCP-dependent mechanism that restrains pyloric gland stem cell proliferation and promotes enteroendocrine differentiation.

Mutators can drive the evolution of multi-resistance to antibiotics.

Antibiotic combination therapies are an approach used to counter the evolution of resistance; their purported benefit is they can stop the successive emergence of independent resistance mutations in the same genome. Here, we show that bacterial populations with 'mutators', organisms with defects in DNA repair, readily evolve resistance to combination antibiotic treatment when there is a delay in reaching inhibitory concentrations of antibiotic-under conditions where purely wild-type populations cannot. In populations of Escherichia coli subjected to combination treatment, we detected a diverse array of acquired mutations, including multiple alleles in the canonical targets of resistance for the two drugs, as well as mutations in multi-drug efflux pumps and genes involved in DNA replication and repair. Unexpectedly, mutators not only allowed multi-resistance to evolve under combination treatment where it was favoured, but also under single-drug treatments. Using simulations, we show that the increase in mutation rate of the two canonical resistance targets is sufficient to permit multi-resistance evolution in both single-drug and combination treatments. Under both conditions, the mutator allele swept to fixation through hitch-hiking with single-drug resistance, enabling subsequent resistance mutations to emerge. Ultimately, our results suggest that mutators may hinder the utility of combination therapy when mutators are present. Additionally, by raising the rates of genetic mutation, selection for multi-resistance may have the unwanted side-effect of increasing the potential to evolve resistance to future antibiotic treatments.