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Microglia and complement can mediate neurodegeneration in Alzheimer’s disease (AD). By integrative multi-omics analysis, here we show that astrocytic and microglial proteins are increased in TauP301S synapse fractions with age and in a C1q-dependent manner. In addition to microglia, we identified that astrocytes contribute substantially to synapse elimination in TauP301S hippocampi. Notably, we found relatively more excitatory synapse marker proteins in astrocytic lysosomes, whereas microglial lysosomes contained more inhibitory synapse material. C1q deletion reduced astrocyte–synapse association and decreased astrocytic and microglial synapses engulfment in TauP301S mice and rescued synapse density. Finally, in an AD mouse model that combines β-amyloid and Tau pathologies, deletion of the AD risk gene Trem2 impaired microglial phagocytosis of synapses, whereas astrocytes engulfed more inhibitory synapses around plaques. Together, our data reveal that astrocytes contact and eliminate synapses in a C1q-dependent manner and thereby contribute to pathological synapse loss and that astrocytic phagocytosis can compensate for microglial dysfunction.

Stenotrophomonas maltophilia most often infects the lungs, where the physiologic environment is naturally slightly acidic (pH ~6.6), compared to most parts of the body (such as the bloodstream), which have neutral pH values (~7.4). Pneumonia due to S. maltophilia is often treated with the antibiotic levofloxacin, despite the activity of levofloxacin being known to be impaired at acidic pH.

TREM2 is an Alzheimer's disease (AD) risk gene expressed in microglia. To study the role of Trem2 in a mouse model of β-amyloidosis, we compared PS2APP transgenic mice versus PS2APP mice lacking Trem2 (PS2APP;Trem2ko) at ages ranging from 4 to 22 months. Microgliosis was impaired in PS2APP;Trem2ko mice, with Trem2-deficient microglia showing compromised expression of proliferation/Wnt-related genes and marked accumulation of ApoE., TREM2 is an Alzheimer's disease (AD) risk gene expressed in microglia. To study the role of Trem2 in a mouse model of β-amyloidosis, we compared PS2APP transgenic mice versus PS2APP mice lacking Trem2 (PS2APP;Trem2ko) at ages ranging from 4 to 22 months. Microgliosis was impaired in PS2APP;Trem2ko mice, with Trem2-deficient microglia showing compromised expression of proliferation/Wnt-related genes and marked accumulation of ApoE. Plaque abundance was elevated in PS2APP;Trem2ko females at 6–7 months; but by 12 or 19–22 months of age, it was notably diminished in female and male PS2APP;Trem2ko mice, respectively. Across all ages, plaque morphology was more diffuse in PS2APP;Trem2ko brains, and the Aβ42:Aβ40 ratio was elevated. The amount of soluble, fibrillar Aβ oligomers also increased in PS2APP;Trem2ko hippocampi. Associated with these changes, axonal dystrophy was exacerbated from 6 to 7 months onward in PS2APP;Trem2ko mice, notwithstanding the reduced plaque load at later ages. PS2APP;Trem2ko mice also exhibited more dendritic spine loss around plaque and more neurofilament light chain in CSF. Thus, aggravated neuritic dystrophy is a more consistent outcome of Trem2 deficiency than amyloid plaque load, suggesting that the microglial packing of Aβ into dense plaque is an important neuroprotective activity. SIGNIFICANCE STATEMENT Genetic studies indicate that TREM2 gene mutations confer increased Alzheimer's disease (AD) risk. We studied the effects of Trem2 deletion in the PS2APP mouse AD model, in which overproduction of Aβ peptide leads to amyloid plaque formation and associated neuritic dystrophy. Interestingly, neuritic dystrophies were intensified in the brains of Trem2-deficient mice, despite these mice displaying reduced plaque accumulation at later ages (12–22 months). Microglial clustering around plaques was impaired, plaques were more diffuse, and the Aβ42:Aβ40 ratio and amount of soluble, fibrillar Aβ oligomers were elevated in Trem2-deficient brains. These results suggest that the Trem2-dependent compaction of Aβ into dense plaques is a protective microglial activity, limiting the exposure of neurons to toxic Aβ species.

Asphaltene deposition in petroleum refineries is known to be problematic as it reduces efficiencyand may lead to structural failure or production downtime. Though several successful approacheshave been utilized to limit deposition through the addition of dispersants and inhibitors topetroleum, these methods require constant intervention and are often expensive. In this study, wedemonstrate an innovative technique to engineer the surface chemistry of pipeline alloy steels toinhibit asphaltene deposition. Pack aluminization, a standard industrial-scale chemical vapordeposition process, is employed at a low temperature of 600 oC to aluminize API 5L X65 highstrength pipe steel substrates. The results showed deposit free steel surfaces after high-pressureand high-temperature fouling experiments. The improvement is attributed to the formation of analuminide intermetallic phase of Fe2Al5, which changes the native oxide chemistry to favoralumina over hematite. The continuous passivating oxide scale, acting as a protective barrier, mitigates asphaltene deposition and sulfidic corrosion. Since this process is based on alloying thesurface of the steel and is not a coating, it is not prone to delamination, and it can be reformedwhen damaged within the aluminized region. The combination of low-cost processing andimproved anti-fouling characteristics makes surface chemistry modification of steel a promisingpreventative approach against asphaltene deposition.

The rise in innovative digital health technologies has led a paradigm shift in health care toward personalized, patient-centric medicine that is reaching beyond traditional brick-and-mortar facilities into patients’ homes and everyday lives. Digital solutions can monitor and detect early changes in physiological data, predict disease progression and health-related outcomes based on individual risk factors, and manage disease intervention with a range of accessible telemedicine and mobile health options. In this review, we discuss the unique transformation underway in the care of patients with liver disease, specifically examining the digital transformation of diagnostics, prediction and clinical decision-making, and management. Additionally, we discuss the general considerations needed to confirm validity and oversight of new technologies, usability and acceptability of digital solutions, and equity and inclusivity of vulnerable populations.

Some protein positions play special roles in determining the magnitude of protein function: at such “rheostat” positions, varied amino acid substitutions give rise to a continuum of functional outcomes, from wild type (or enhanced), to intermediate, to loss of function. This observed range raises interesting questions about the biophysical bases by which changes at single positions have such varied outcomes. Here, we assessed variants at position 98 in human aldolase A (“I98X”). Despite being ~17 Å from the active site and far from subunit interfaces, substitutions at position 98 have rheostatic contributions to the apparent cooperativity (n ( H )) associated with fructose‐1,6‐bisphosphate substrate binding and moderately affected binding affinity. Next, we crystallized representative I98X variants to assess structural consequences. Residues smaller than the native isoleucine (cysteine and serine) were readily accommodated, and the larger phenylalanine caused only a slight separation of the two parallel helixes. However, the diffraction quality was reduced for I98F, and further reduced for I98Y. Intriguingly, the resolutions of the I98X structures correlated with their n ( H ) values. We propose that substitution effects on both n ( H ) and crystal lattice disruption arise from changes in the population of aldolase A conformations in solution. In combination with results computed for rheostat positions in other proteins, the results from this study suggest that rheostat positions accommodate a wide range of side chains and that structural consequences manifest as shifted ensemble populations and/or dynamics changes.

Background: Vancomycin-resistant Enterococcus faecium (VRE) in particular has evolved as an important cause of hospital acquired infection, especially in immunocompromised hosts. Methods: We present a complex case of a patient with relapsed acute myeloid leukemia who underwent allogenic hematopoietic stem cell transplantation complicated by persistent VRE bacteremia and meningitis. To optimize therapy, various blood and cerebrospinal fluid (CSF) samples were sent to a research laboratory for extensive susceptibility testing, pharmacokinetic analyses, and time-kill experiments. Results: In vitro testing revealed resistance to all first-line treatment options and CSF sampling demonstrated sub-optimal central nervous system concentrations achieved by each antimicrobial agent administered in relation to their respective MIC value. Time-kill analyses at observed CSF concentrations confirmed the lack of bactericidal activity despite use of a four-drug combination regimen. Conclusions: This work is the first to report CSF concentrations of oritavancin and tedizolid in humans and adds to the limited data regarding in vitro susceptibility of new antimicrobial agents such as eravacycline, omadacycline, and lefamulin against VRE. Our study provides new insights into various aspects of treatment of extensively drug-resistant Enterococcus faecium meningitis and bacteremia and supports the continued pursuit of precision medicine for these challenging cases.

When amino acids vary during evolution, the outcome can be functionally neutral or biologically-important. We previously found that substituting a subset of nonconserved positions, "rheostat" positions, can have surprising effects on protein function. Since changes at rheostat positions can facilitate functional evolution or cause disease, more examples are needed to understand their unique biophysical characteristics. Here, we explored whether "phylogenetic" patterns of change in multiple sequence alignments (such as positions with subfamily specific conservation) predict the locations of functional rheostat positions. To that end, we experimentally tested eight phylogenetic positions in human liver pyruvate kinase (hLPYK), using 10-15 substitutions per position and biochemical assays that yielded five functional parameters. Five positions were strongly rheostatic and three were non-neutral. To test the corollary that positions with low phylogenetic scores were not rheostat positions, we combined these phylogenetic positions with previously-identified hLPYK rheostat, "toggle" (most substitution abolished function), and "neutral" (all substitutions were like wild-type) positions. Despite representing 428 variants, this set of 33 positions was poorly statistically powered. Thus, we turned to the in vivo phenotypic dataset for E. coli lactose repressor protein (LacI), which comprised 12-13 substitutions at 329 positions and could be used to identify rheostat, toggle, and neutral positions. Combined hLPYK and LacI results show that positions with strong phylogenetic patterns of change are more likely to exhibit rheostat substitution outcomes than neutral or toggle outcomes. Furthermore, phylogenetic patterns were more successful at identifying rheostat positions than were co-evolutionary or eigenvector centrality measures of evolutionary change.

To develop machine learning algorithms (MLAs) that can differentiate patients with acute cholangitis (AC) and alcohol-associated hepatitis (AH) using simple laboratory variables.A study was conducted of 459 adult patients admitted to Mayo Clinic, Rochester, with AH (n=265) or AC (n=194) from January 1, 2010, to December 31, 2019. Ten laboratory variables (white blood cell count, hemoglobin, mean corpuscular volume, platelet count, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total bilirubin, direct bilirubin, albumin) were collected as input variables. Eight supervised MLAs (decision tree, naive Bayes, logistic regression, k-nearest neighbor, support vector machine, artificial neural networks, random forest, gradient boosting) were trained and tested for classification of AC vs AH. External validation was performed with patients with AC (n=213) and AH (n=92) from the MIMIC-III database. A feature selection strategy was used to choose the best 5-variable combination. There were 143 physicians who took an online quiz to distinguish AC from AH using the same 10 laboratory variables alone.The MLAs demonstrated excellent performances with accuracies up to 0.932 and area under the curve (AUC) up to 0.986. In external validation, the MLAs showed comparable accuracy up to 0.909 and AUC up to 0.970. Feature selection in terms of information-theoretic measures was effective, and the choice of the best 5-variable subset produced high performance with an AUC up to 0.994. Physicians did worse, with mean accuracy of 0.790.Using a few routine laboratory variables, MLAs can differentiate patients with AC and AH and may serve valuable adjunctive roles in cases of diagnostic uncertainty.

This front-end engineering and design (FEED) study is for a carbon dioxide (CO2) capture system for Unit #2 (816 MW) at the Prairie State Generating Company’s (PSGC) Energy Campus in Marissa, IL. The capture technology used is the Advanced KM CDR Process™ from Mitsubishi Heavy Industries (MHI). The project will be the largest post-combustion capture plant in the world. In addition, it will incorporate advancements in the technology including lessons learned from past projects and a new proprietary solvent. The overall business model being developed by PSGC focuses on the generation of 45Q tax credits as a result of sequestering the captured CO2. Because the Prairie Research Institute (PRI) within the University of Illinois at Urbana-Champaign (UIUC) leads both this capture effort and the storage effort, there is close coordination and integration between the capture and storage efforts. This integration is vital to achieving the desired business targets for the project.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The production of an L1 metallo-β-lactamase and an L2 serine active-site β-lactamase precludes the use of β-lactams for the treatment of Stenotrophomonas maltophilia infections. Preclinical data suggest that cefiderocol is the first approved β-lactam with reliable activity against S. maltophilia, but data on strains resistant to current first-line agents are limited, and no studies have assessed cefiderocol-based combinations. The objective of this study was to evaluate and compare the in vitro activity of cefiderocol alone and in combination with levofloxacin, minocycline, polymyxin B, or trimethoprim-sulfamethoxazole (TMP-SMZ) against a collection of highly resistant clinical S. maltophilia isolates., The production of an L1 metallo-β-lactamase and an L2 serine active-site β-lactamase precludes the use of β-lactams for the treatment of Stenotrophomonas maltophilia infections. Preclinical data suggest that cefiderocol is the first approved β-lactam with reliable activity against S. maltophilia, but data on strains resistant to current first-line agents are limited, and no studies have assessed cefiderocol-based combinations. The objective of this study was to evaluate and compare the in vitro activity of cefiderocol alone and in combination with levofloxacin, minocycline, polymyxin B, or trimethoprim-sulfamethoxazole (TMP-SMZ) against a collection of highly resistant clinical S. maltophilia isolates. For this purpose, the MICs of cefiderocol, ceftazidime, levofloxacin, minocycline, polymyxin B, and TMP-SMZ for 37 S. maltophilia isolates not susceptible to levofloxacin and/or TMP-SMZ were determined. Nine strains with various cefiderocol MICs were then tested in time-kill experiments with cefiderocol alone and in combination with comparators. The only agents for which susceptibility rates exceeded 40% were cefiderocol (100%) and minocycline (97.3%). Cefiderocol displayed the lowest MIC50 and MIC90 values (0.125 and 0.5 mg/liter, respectively). In time-kill experiments, synergy was observed when cefiderocol was combined with levofloxacin, minocycline, polymyxin B, or TMP-SMZ against 4/9 (44.4%), 6/9 (66.7%), 5/9 (55.5%), and 6/9 (66.7%) isolates, respectively. These data suggest that cefiderocol displays potent in vitro activity against S. maltophilia, including strains resistant to currently preferred agents. Future dynamic and in vivo studies of cefiderocol alone and in combination are warranted to further define cefiderocol’s synergistic capabilities and its place in therapy for S. maltophilia infections.

PURPOSE OF REVIEW: Acute on chronic liver failure (ACLF) is a unique syndrome that afflicts patients with chronic liver disease and results in high short-term mortality, > 50% at 28 days in patients with severe ACLF (grade 3, ACLF-3). Given this prognosis, there is an urgent need to understand risk factors for this condition, as well as selection criteria for patients who may benefit from liver transplantation (LT). RECENT FINDINGS: Several studies have identified risk factors for developing ACLF, including higher model for end-stage liver disease score, anemia, and morbid obesity, as well ACLF mortality, such as infection, increasing organ failures, and higher white blood cell count. Prognostic tools are now available as online calculators. Regarding LT in ACLF, data suggest that even patients with ACLF-3 may do well after LT, with 1-year survival > 80% in several studies. Improvement in organ failures prior to LT, higher donor quality, and lack of mechanical ventilation further improve outcomes. Importantly, ACLF-3 patients may have higher short-term wait list mortality than patients listed status-1a, suggesting that increased LT prioritization may be warranted. SUMMARY: ACLF is a high-mortality condition that frequently responds well to LT. Ongoing efforts to understand the natural history of ACLF and predictors of improved post-LT survival will facilitate LT criteria for this condition, which may ultimately include increased LT prioritization for selected patients.

Habitat loss is a leading cause of species declines worldwide (1, 2). Using the Land Use Harmonization dataset (3) as the basis for ecological niche modelling, we quantify modelled changes in global suitable habitat over the past three centuries for Asian elephants, a megaherbivore representing diverse biomes. Between 1700-2015 over 60% of habitat suitable for elephants was lost, while average patch size declined 84-86%, and the largest patch decreased from 45% to 5%. Over half of the currently inhabited range is considered unsuitable for elephants, whereas suitable habitat is predicted to decline further from 2015-2099 across all six scenarios representing a range of emissions pathways and socioeconomic narratives. However, results vary by region and scenario in a non-linear manner, indicating that socioeconomic outcomes are as important as emissions pathways for the future of these habitats. Lao PDR, Thailand and Myanmar currently have lower elephant populations relative to the amount of available habitat. On the other hand, continued losses in densely settled areas such as India and Sri Lanka are expected to exacerbate human-elephant conflict. Only a few regions, notably peninsular Malaysia, Borneo, and Yunnan province, China, are predicted to have potential for habitat recovery. The most catastrophic losses across all range states occurred under a scenario of mid-range emissions but high regional inequities, leading to overexploitation of critical habitats. We conclude that steps to mitigate climate change must be taken alongside measures to ensure inter-regional social equity in order to safeguard these landscapes for elephants, humans and other species. Significance Human land-use change is a leading driver of biodiversity loss, but effects are difficult to quantify over centennial timescales. Asian elephants occupy diverse biomes that have long been impacted by human activities and are thus indicative of the fates of numerous co-existing species. Over 60% of suitable elephant habitat has been lost since the 1700s and over half of the currently inhabited range may be considered unsuitable. Declines are predicted to continue to 2099 under six scenarios of global change across the majority of elephant range states, with the worst losses corresponding to a scenario representing mid-range emissions but high global inequity. Thus climate change mitigation strategies must include measures to facilitate equitable societies to safeguard and recover elephant landscapes, together with the unique biodiversity they represent.

Governments around the world are responding to the novel coronavirus (COVID-19) pandemic1 with unprecedented policies designed to slow the growth rate of infections. Many actions, such as closing schools and restricting populations to their homes, impose large and visible costs on society. In contrast, the benefits of these policies, in the form of infections that did not occur, cannot be directly observed and are currently understood through process-based simulations.2–4 Here, we compile new data on 936 local, regional, and national anti-contagion policies recently deployed in the ongoing pandemic across localities in China, South Korea, Iran, Italy, France, and the United States (US). We then apply reduced-form econometric methods, commonly used to measure the effect of policies on economic growth, to empirically evaluate the effect that these anti-contagion policies have had on the growth rate of infections. In the absence of any policy actions, we estimate that early infections of COVID-19 exhibit exponential growth rates of roughly 45% per day. We find that anti-contagion policies collectively have had significant effects slowing this growth, although policy actions in the US appear to be too recent to have a substantial impact since the magnitude of these effects grows over time. Our results suggest that similar policies may have different impacts on different populations, but we obtain consistent evidence that the policy packages now deployed are achieving large and beneficial health outcomes. We estimate that, to date, current policies have already prevented or delayed on the order of eighty-million infections. These findings may help inform whether or when ongoing policies should be lifted or intensified, and they can support decision-making in the over 150 countries where COVID-19 has been detected but not yet achieved high infection rates.5

IntroductionMore than 93,000 cases of coronavirus disease (COVID-19) have been reported worldwide. We describe the epidemiology, clinical course, and virologic characteristics of the first 12 U.S. patients with COVID-19.MethodsWe collected demographic, exposure, and clinical information from 12 patients confirmed by CDC during January 20–February 5, 2020 to have COVID-19. Respiratory, stool, serum, and urine specimens were submitted for SARS-CoV-2 rRT-PCR testing, virus culture, and whole genome sequencing.ResultsAmong the 12 patients, median age was 53 years (range: 21–68); 8 were male, 10 had traveled to China, and two were contacts of patients in this series. Commonly reported signs and symptoms at illness onset were fever (n=7) and cough (n=8). Seven patients were hospitalized with radiographic evidence of pneumonia and demonstrated clinical or laboratory signs of worsening during the second week of illness. Three were treated with the investigational antiviral remdesivir. All patients had SARS-CoV-2 RNA detected in respiratory specimens, typically for 2–3 weeks after illness onset, with lowest rRT-PCR Ct values often detected in the first week. SARS-CoV-2 RNA was detected after reported symptom resolution in seven patients. SARS-CoV-2 was cultured from respiratory specimens, and SARS-CoV-2 RNA was detected in stool from 7/10 patients.ConclusionsIn 12 patients with mild to moderately severe illness, SARS-CoV-2 RNA and viable virus were detected early, and prolonged RNA detection suggests the window for diagnosis is long. Hospitalized patients showed signs of worsening in the second week after illness onset.

Alcoholic hepatitis (AH) is a condition of acute liver inflammation in the setting of heavy alcohol use that is often managed with corticosteroids in severe cases. Among non-responders to steroids, however, prognosis is poor with up to 75% mortality within 6 months after treatment failure. Early liver transplantation (LT) can achieve an acceptable short-term survival, and initial studies have demonstrated 3-year survival rates of up to 84%. However, the practice of early LT in severe AH remains controversial with concerns over the 6-month rule of sobriety and risk of alcohol relapse post-transplant. Proponents of LT advocate for better understanding of alcohol use as a disorder rather than self-inflicted cause of illness, aim to redefine the misguided application of the 6-month rule, and point out similar relapse rates among patients with early LT and those with greater than 6 months abstinence before transplant. Opponents of LT emphasize the correlation between alcohol relapse and graft failure and mortality, public resistance and potential for distrust among donors, and arguments that transplant centers need to establish improved models to predict relapse and standardize candidate selection criteria across centers. Here we review recent literature on this controversy and provide recommendations for moving forward to consensus.

Stenotrophomonas maltophilia is difficult to treat due to the production of multiple intrinsic and acquired mechanisms of resistance. Trimethoprim-sulfamethoxazole (TMP-SMZ) and the fluoroquinolones have traditionally been considered the drugs of choice but are plagued by increasing resistance and adverse drug effects. The objective of this study was to evaluate the in vitro activities of 12 clinically relevant antimicrobials against clinical S. maltophilia isolates nonsusceptible to levofloxacin and/or TMP-SMZ. A diverse panel of 41 clinical S. maltophilia isolates collected through the SENTRY Antimicrobial Surveillance Program from 2008 to 2018 was evaluated against ceftazidime, ceftazidime-avibactam, chloramphenicol, delafloxacin, levofloxacin, moxifloxacin, eravacycline, minocycline, omadacycline, polymyxin B, and tigecycline. MICs were determined in triplicate via reference broth microdilution and interpreted according to CLSI guidelines where available. MIC distributions and susceptibilities were also compared across infection type, acquisition setting, and geographic origin. Susceptibilities to levofloxacin and TMP-SMZ were 29.3% and 36.6%, respectively. Minocycline displayed the highest susceptibility rate overall (92.7%) and the lowest MIC(90) value (4 mg/liter) of any of the 12 agents tested. Only 3 isolates were resistant to levofloxacin, TMP-SMZ, and minocycline. Polymyxin B and tigecycline were the second most active agents. No significant differences were observed in MIC distributions across the 3 strata evaluated. These data demonstrate that few antimicrobials, old or new, maintain reliable activity against resistant S. maltophilia. The role of minocycline in the treatment of infections due to S. maltophilia warrants further clinical investigation given its potent in vitro activity and favorable adverse effect profile.

For protein mutagenesis, a common expectation is that important positions will behave like on/off “toggle” switches (i.e., a few substitutions act like wildtype, most abolish function). However, there exists another class of important positions that manifests a wide range of functional outcomes upon substitution: “rheostat” positions. Previously, we evaluated rheostat positions located near the allosteric binding sites for inhibitor alanine (Ala) and activator fructose-1,6-bisphosphate (Fru-1,6-BP) in human liver pyruvate kinase. When substituted with multiple amino acids, many positions demonstrated moderate rheostatic effects on allosteric coupling between effector binding and phosphoenolpyruvate (PEP) binding in the active site. Nonetheless, the combined outcomes of all positions sampled the full range of possible allosteric coupling (full tunability). However, that study only evaluated allosteric tunability of “local” positions, i.e., positions were located near the binding sites of the allosteric ligand being assessed. Here, we evaluated tunability of allosteric coupling when mutated sites were distant from the allosterically-coupled binding sites. Positions near the Ala binding site had rheostatic outcomes on allosteric coupling between Fru-1,6-BP and PEP binding. In contrast, positions in the Fru-1,6-BP site exhibited modest effects on coupling between Ala and PEP binding. Analyzed in aggregate, both PEP/Ala and PEP/Fru-1,6-BP coupling were again fully tunable by amino acid substitutions at this limited set of distant positions. Furthermore, some positions exhibited rheostatic control over multiple parameters and others exhibited rheostatic effects on one parameter and toggle control over a second. These findings highlight challenges in efforts to both predict/interpret mutational outcomes and engineer functions into proteins.

Understanding how each residue position contributes to protein function has been a long-standing goal in protein science. Substitution studies have historically focused on conserved protein positions. However, substitutions of nonconserved positions can also modify function. Indeed, we recently identified nonconserved positions that have large substitution effects in human liver pyruvate kinase (hLPYK), including altered allosteric coupling. To facilitate a comparison of which characteristics determine when a nonconserved position does vs. does not contribute to function, the goal of the current work was to identify neutral positions in hLPYK. However, existing hLPYK data showed that three features commonly associated with neutral positions – high sequence entropy, high surface exposure, and alanine scanning – lacked the sensitivity needed to guide experimental studies. We used multiple evolutionary patterns identified in a sequence alignment of the PYK family to identify which positions were least patterned, reasoning that these were most likely to be neutral. Nine positions were tested with a total of 117 amino acid substitutions. Although exploring all potential functions is not feasible for any protein, five parameters associated with substrate/effector affinities and allosteric coupling were measured for hLPYK variants. For each position, the aggregate functional outcomes of all variants were used to quantify a “neutrality” score. Three positions showed perfect neutral scores for all five parameters. Furthermore, the nine positions showed larger neutral scores than 17 positions located near allosteric binding sites. Thus, our strategy successfully enriched the dataset for positions with neutral and modest substitutions.

Background: There are several congenital hand differences that cause thumb-index (TI) web space deficiency. There is a knowledge gap in the literature about the hand differences that are associated with TI web space deficiency. We aimed to identify these congenital differences and the various specific reconstructive surgical procedures that are used for these conditions. Methods: We conducted a retrospective chart review of children treated operatively over a period of 30 years for congenital TI web space deficiency by the senior author (G.M.R.). We gathered data on demographics and associated congenital hand differences and compiled a list of all surgical procedures performed for the web space and the ipsilateral upper extremity. Results: We included 71 patients (77 hands) with 12 congenital hand differences (62 developmental and 9 spastic). The total number of upper extremity operations, (ie), anesthetics performed for these patients was 186, averaging 2.6 settings and 7.5 procedures for each patient. Cutaneous reconstructive procedures included first dorsal metacarpal artery pedicle flaps (49 patients), 4-flap Z-plasties (15), and transposition flaps (13). In addition, 16 different thumb reconstructive procedures were necessary. Ten patients required revision of their TI web space procedures for recurrence. Conclusions: The prevalence of TI web space deficiency is underappreciated. These patients often have multiple musculoskeletal anomalies of the hand and upper extremity that should be ruled out and require surgical treatment to optimize hand function. Consideration should be given to performing more than one procedure in one setting when possible.

Fouling of processing units because of asphaltene deposition is a common phenomenon that interrupts the operation of oil refineries. In this study, the deposition behavior of a model archipelago asphaltene was investigated in the temperature range of 150 oC to 350 oC. For a fixed surface chemistry, the differences in deposit chemistry with fouling temperature is a function of the thermochemical properties of the model asphaltene. Under static high pressure and high temperature fouling conditions, both surface roughness and chemistry play an important role in asphaltene deposition. Rough surfaces are shown to develop larger deposits because of less restrictive physical barriers to inhibit deposit growth. Passivating the surface with an alumina chemistry significantly reduces the impact of surface roughness, as well as the total amount of deposition. This beneficial effect of using a protective alumina chemistry is attributed to its high thermal stability and low diffusivity that inhibit the uncontrolled formation of thiolate and sulfide deposits that are found on unpassivated steels. Instead, alumina modifies the surface reaction to a self-limiting chemisorption and oxidation process that produces thin sulfate deposits at the surface. With further consideration to the reactive species present in solution, the findings of this study may be extended to determine suitable surface conditions that mitigate asphaltene fouling.

Summary Synapse loss and Tau pathology are hallmarks of Alzheimer’s disease (AD) and other tauopathies, but how Tau pathology causes synapse loss is unclear. We used unbiased proteomic analysis of postsynaptic densities (PSDs) in Tau-P301S transgenic mice to identify Tau-dependent alterations in synapses prior to overt neurodegeneration. Multiple proteins and pathways were altered in Tau-P301S PSDs, including depletion of a set of GTPase-regulatory proteins that leads to actin cytoskeletal defects and loss of dendritic spines. Furthermore, we found striking accumulation of complement C1q in the PSDs of Tau-P301S mice and AD patients. At synapses, C1q decorated perisynaptic membranes, accumulated in correlation with phospho-Tau, and was associated with augmented microglial engulfment of synapses and decline of synapse density. A C1q-blocking antibody inhibited microglial synapse removal in cultured neurons and in Tau-P301S mice, rescuing synapse density. Thus, inhibiting complement-mediated synapse removal by microglia could be a potential therapeutic target for Tau-associated neurodegeneration.

Eukaryotic cells are sensitive to mechanical forces they experience from the environment. The process of mechanosensation is complex, and involves elements such as the cytoskeleton and active contraction from myosin motors. Ultimately, mechanosensation is connected to changes in gene expression in the cell, known as mechanotransduction. While the involvement of the cytoskeleton in mechanosensation is known, the processes upstream of cytoskeletal changes are unclear. In this paper, by using a microfluidic device that mechanically compresses live cells, we demonstrate that Ca2+ currents and membrane tension-sensitive ion channels directly signal to the Rho GTPase and myosin contraction. In response to membrane tension changes, cells actively regulate cortical myosin contraction to balance external forces. The process is captured by a mechanochemical model where membrane tension, myosin contraction and the osmotic pressure difference between the cytoplasm and extracellular environment are connected by mechanical force balance. Finally, to complete the picture of mechanotransduction, we find that the tension-sensitive transcription factor YAP family of proteins translocate from the nucleus to the cytoplasm in response to mechanical compression.

Eukaryotic cells are sensitive to mechanical forces they experience from the environment. The process of mechanosensation is complex, and involves elements such as the cytoskeleton and active contraction from myosin motors. Ultimately, mechanosensation is connected to changes in gene expression in the cell, known as mechanotransduction. While the involvement of the cytoskeleton in mechanosensation is known, the processes upstream of cytoskeletal changes are unclear. In this paper, by using a microfluidic device that mechanically compresses live cells, we demonstrate that Ca2+ currents and membrane tension-sensitive ion channels directly signal to the Rho GTPase and myosin contraction. In response to membrane tension changes, cells actively regulate cortical myosin contraction to balance external forces. The process is captured by a mechanochemical model where membrane tension, myosin contraction and the osmotic pressure difference between the cytoplasm and extracellular environment are connected by mechanical force balance. Finally, to complete the picture of mechanotransduction, we find that the tension-sensitive transcription factor YAP family of proteins translocate from the nucleus to the cytoplasm in response to mechanical compression.

Eukaryotic cells are sensitive to mechanical forces that they experience from the environment. The process of mechanosensation is complex, and involves elements such as the cytoskeleton and active contraction from myosin motors. Ultimately, mechanosensation is connected to changes in gene expression in the cell, or mechanotransduction. While the involvement of the cytoskeleton in mechanosensation is known, processes upstream to cytoskeletal changes is unclear. In this paper, using a microfluidic device that mechanically compresses live cells, we demonstrate that calcium currents and membrane tension-sensitive ion channels directly signals to the Rho GTPase and myosin contraction. In response to membrane tension changes, cell actively regulates cortical myosin contraction to balance external forces. The process is captured by a mechanochemical model where membrane tension, myosin contraction and the osmotic pressure difference between the cytoplasm and extracellular environment are connected by mechanical force-balance. Finally, to complete the picture of mechanotransduction, we find that the tension-sensitive transcription factor YAP translocates from the nucleus to the cytoplasm in response to mechanical compression.

Lipid disequilibrium induced by inhibition of long-chain acyl-CoA synthetases impairs ERAD substrate glycan trimming and dislocation independently of its effects on lipid droplet biogenesis. The disruptions in ER proteostasis activate the IRE1 and PERK branches of the unfolded protein response and ultimately induce IRE1-dependent cell death., The endoplasmic reticulum (ER) mediates the folding, maturation, and deployment of the secretory proteome. Proteins that fail to achieve their native conformation are retained in the ER and targeted for clearance by ER-associated degradation (ERAD), a sophisticated process that mediates the ubiquitin-dependent delivery of substrates to the 26S proteasome for proteolysis. Recent findings indicate that inhibition of long-chain acyl-CoA synthetases with triacsin C, a fatty acid analogue, impairs lipid droplet (LD) biogenesis and ERAD, suggesting a role for LDs in ERAD. However, whether LDs are involved in the ERAD process remains an outstanding question. Using chemical and genetic approaches to disrupt diacylglycerol acyltransferase (DGAT)–dependent LD biogenesis, we provide evidence that LDs are dispensable for ERAD in mammalian cells. Instead, our results suggest that triacsin C causes global alterations in the cellular lipid landscape that disrupt ER proteostasis by interfering with the glycan trimming and dislocation steps of ERAD. Prolonged triacsin C treatment activates both the IRE1 and PERK branches of the unfolded protein response and ultimately leads to IRE1-dependent cell death. These findings identify an intimate relationship between fatty acid metabolism and ER proteostasis that influences cell viability.

Assessing BACE1 (β-site APP cleaving enzyme 1) knockout mice for general health and neurological function may be useful in predicting risks associated with prolonged pharmacological BACE1 inhibition, a treatment approach currently being developed for Alzheimer’s disease. To determine whether BACE1 deletion-associated effects in mice generalize to another species, we developed a novel Bace1−/− rat line using zinc-finger nuclease technology and compared Bace1−/− mice and rats with their Bace1+/+ counterparts. Lack of BACE1 was confirmed in Bace1−/− animals from both species. Removal of BACE1 affected startle magnitude, balance beam performance, pain response, and nerve myelination in both species. While both mice and rats lacking BACE1 have shown increased mortality, the increase was smaller and restricted to early developmental stages for rats. Bace1−/− mice and rats further differed in body weight, spontaneous locomotor activity, and prepulse inhibition of startle. While the effects of species and genetic background on these phenotypes remain difficult to distinguish, our findings suggest that BACE1’s role in myelination and some sensorimotor functions is consistent between mice and rats and may be conserved in other species. Other phenotypes differ between these models, suggesting that some effects of BACE1 inhibition vary with the biological context (e.g. species or background strain).

Background & Aims Liver transplantation for patients with acute-on-chronic liver failure (ACLF) with 3 or more failing organs (ACLF-3) is controversial. We compared liver waitlist mortality or removal according to model for end-stage liver disease (MELD) score vs ACLF category. We also studied factors associated with reduced odds of survival for 1 year after liver transplantation in patients with ACLF-3. Methods We analyzed data from the United Network for Organ Sharing (UNOS) from 2005 through 2016. We identified patients who were on the waitlist (100,594) and those who received liver transplants (50,552). Patients with ACLF were identified based on the European Association for the Study of the Liver-chronic liver failure criteria. Outcomes were evaluated with competing risks regression, Kaplan-Meier analysis, and Cox proportional hazards regression. Results Patients with ACLF-3 were more likely to die or be removed from the waitlist, regardless of MELD-sodium (MELD-Na) score, compared with the other ACLF groups; the proportion was greatest for patients with an ACLF-3 score and MELD-Na score below 25 (43.8% at 28 days). Mechanical ventilation at liver transplantation (hazard ratio [HR] 1.49; 95% confidence interval [CI] 1.22–1.84), donor risk index above 1.7 (HR 1.22; 95% CI 1.09–1.35), and liver transplantation within 30 days of listing (HR 0.89; 95% CI 0.81–0.98) were independently associated with survival for 1 year after liver transplantation Conclusions In an analysis of data from the UNOS registry, we found high mortality among patients with ACLF-3 on the liver transplant waitlist, even among those with lower MELD-Na scores. So, certain patients with ACLF-3 have poor outcomes regardless of MELD-Na score. Liver transplantation increases odds of survival for these patients, particularly if performed within 30 days of placement on the waitlist. Mechanical ventilation at liver transplantation and use of marginal organs were associated with increased risk of death.

ObjectiveProductive communication among clinical practitioners is essential if recommendations regarding practice are to exist. The durability of vascular procedures is often influenced by factors such as lesion classification and runoff quality. It is the purpose of this article to determine how reproducible these measures are in the hands of various specialists who deal extensively with peripheral arterial disease.MethodsThe peripheral arteriograms of 100 patients undergoing percutaneous intervention were distributed to six specialists (three vascular surgeons, two interventional radiologists, and one interventional cardiologist). Each was provided with the reference document describing TASC II classification, Society for Vascular Surgery (SVS) runoff score, and simplified runoff score. With no further instruction, each individual was asked to assign each angiogram a TASC II class, SVS runoff score, and a simplified runoff score. Comparisons between the scores assigned were made using kappa statistic.ResultsWhen using the simplified runoff score for grading peripheral arterial disease, there was excellent correlation among readers (k = 0.81; P = .001), even across different specialties. When using TASC II class to grade lesions, there was a greater degree of variation when compared with the simplified runoff score (k = 0.44; P < .05). Finally, there was poor correlation between readers when using the SVS runoff score (k = 0.10; P < .05) and the modified SVS runoff score (k = 0.26; P = .001).ConclusionsDescriptors of clinical disease severity are not universally reproducible. The simplified runoff score is reproducible when interpreted by multiple readers across different specialties and can be used without further modification. The TASC II classification may need minor alterations in description to obtain good correlation among readers. Before the SVS runoff score can be universally adapted, it will need to be described in much better detail or significantly modified.

Although antagonists to GluN2B-containing N-methyl-𝒟-aspartate receptors (NMDARs) have been widely considered to be neuroprotective under certain pathological conditions, their immediate and lasting impacts on synaptic, circuit, and cognitive functions are poorly understood. In hippocampal slices, we found that the GluN2B-selective antagonist Ro25-6981 (Ro25) reduced synaptic NMDAR responses and consequently neuronal output in a subpopulation of GABAergic interneurons, but not pyramidal neurons. Consistent with these effects, Ro25 reduced GABAergic responses in pyramidal neurons and hence could affect circuit functions by altering the excitation/inhibition balance in the brain. In slices from Ts65Dn mice, a Down syndrome model with excess inhibition and cognitive impairment, acutely applied Ro25-rescued long-term potentiation (LTP) and gamma oscillation deficits, whereas prolonged dosing induced persistent rescue of LTP. In contrast, Ro25 did not impact LTP in wild-type (wt) mice but reduced gamma oscillations both acutely and following prolonged treatment. Although acute Ro25 treatment impaired memory performance in wt mice, memory deficits in Ts65Dn mice were unchanged. Thus, GluN2B–NMDARs contribute to the excitation/inhibition balance via impacts on interneurons, and blocking GluN2B–NMDARs can alter functions that depend on this balance, including synaptic plasticity, gamma oscillations, and memory. That prolonged GluN2B antagonism leads to persistent changes in synaptic and circuit functions, and that the influence of GluN2B antagonism differs between wt and disease model mice, provide critical insight into the therapeutic potential and possible liabilities of GluN2B antagonists.

SummaryMetabolites in the kynurenine pathway, generated by tryptophan degradation, are thought to play an important role in neurodegenerative disorders, including Alzheimer's and Huntington's diseases. In these disorders, glutamate receptor-mediated excitotoxicity and free radical formation have been correlated with decreased levels of the neuroprotective metabolite kynurenic acid. Here, we describe the synthesis and characterization of JM6, a small-molecule prodrug inhibitor of kynurenine 3-monooxygenase (KMO). Chronic oral administration of JM6 inhibits KMO in the blood, increasing kynurenic acid levels and reducing extracellular glutamate in the brain. In a transgenic mouse model of Alzheimer's disease, JM6 prevents spatial memory deficits, anxiety-related behavior, and synaptic loss. JM6 also extends life span, prevents synaptic loss, and decreases microglial activation in a mouse model of Huntington's disease. These findings support a critical link between tryptophan metabolism in the blood and neurodegeneration, and they provide a foundation for treatment of neurodegenerative diseases.