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1.
J Thromb Haemost ; 2024 May 06.
Article in English | MEDLINE | ID: mdl-38718926

ABSTRACT

BACKGROUND: Platelets coordinate blood coagulation at sites of vascular injury and play fundamental roles in a wide variety of (patho)physiological processes. Key to many platelet functions is the transport and secretion of proteins packaged within α-granules, organelles produced by platelet precursor megakaryocytes. Prominent among α-granule cargo are fibrinogen (FGN) endocytosed from plasma, and endogenously-synthesized Von Willebrand factor (VWF). These and other proteins are known to require acidic pH for stable packaging. Luminal acidity has been confirmed for mature α-granules isolated from platelets, but direct measurement of megakaryocyte granule acidity has not been reported. OBJECTIVE: To determine the luminal pH of α-granules and their precursors in megakaryocytes, and assess the requirement of vacuolar-type adenosine triphosphatase (V-ATPase) activity establish and maintain the luminal acidity and integrity of these organelles. RESULTS: Using cresyl violet staining, we show that most of the acidic granules detected in megakaryocytes appear to be α-granules/precursors. Endocytosis of FGN tagged with the pH-sensitive fluorescent dye FITC was used to load a subset of these organelles, and ratiometric fluorescence analysis established a median luminal pH of 5.2 (interquartile range 5.0 - 5.5). Inhibition of megakaryocyte V-ATPase activity led to enlargement of cargo-containing compartments detected by fluorescence microscopy and electron microscopy. CONCLUSION: These observations reveal that V-ATPase activity is required to establish and maintain a luminal acidic pH in megakaryocyte α-granules/precursors, confirming its importance for stable packaging of cargo proteins such as VWF.

2.
Mol Neurobiol ; 2024 May 02.
Article in English | MEDLINE | ID: mdl-38696065

ABSTRACT

Heterozygous loss-of-function mutations in the progranulin gene (GRN) are a major cause of frontotemporal dementia due to progranulin haploinsufficiency; complete deficiency of progranulin causes neuronal ceroid lipofuscinosis. Several progranulin-deficient mouse models have been generated, including both knockout mice and knockin mice harboring a common patient mutation (R493X). However, the GrnR493X mouse model has not been characterized completely. Additionally, while homozygous GrnR493X and Grn knockout mice have been extensively studied, data from heterozygous mice is still limited. Here, we performed more in-depth characterization of heterozygous and homozygous GrnR493X knockin mice, which includes biochemical assessments, behavioral studies, and analysis of fluid biomarkers. In the brains of homozygous GrnR493X mice, we found increased phosphorylated TDP-43 along with increased expression of lysosomal genes, markers of microgliosis and astrogliosis, pro-inflammatory cytokines, and complement factors. Heterozygous GrnR493X mice did not have increased TDP-43 phosphorylation but did exhibit limited increases in lysosomal and inflammatory gene expression. Behavioral studies found social and emotional deficits in GrnR493X mice that mirror those observed in Grn knockout mouse models, as well as impairment in memory and executive function. Overall, the GrnR493X knockin mouse model closely phenocopies Grn knockout models. Lastly, in contrast to homozygous knockin mice, heterozygous GrnR493X mice do not have elevated levels of fluid biomarkers previously identified in humans, including neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) in both plasma and CSF. These results may help to inform pre-clinical studies that use this Grn knockin mouse model and other Grn knockout models.

3.
Blood ; 2024 May 31.
Article in English | MEDLINE | ID: mdl-38820590

ABSTRACT

Deficiency of X-linked Inhibitor of Apoptosis Protein (XIAP) is a rare genetic condition that can present with recurrent episodes of hemophagocytic lymphohistiocytosis (HLH), though the exact mechanisms leading to this hyperinflammatory disorder are unclear. Understanding its biology is critical to developing targeted therapies for this potentially fatal disease. Here we report on a novel multi-exonic intragenic duplication leading to XIAP deficiency with recurrent HLH that demonstrated complete response to interleukin (IL)-1b blockade. We further demonstrate using both primary patient cells and genetically modified THP-1 monocyte cell lines that, contrary to what has previously been shown in mouse cells, XIAP-deficient human macrophages do not produce excess IL-1b when stimulated under standard conditions. Instead, NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-mediated hyperproduction of IL-1b is observed only when the XIAP-deficient cells are stimulated under autophagy-promoting conditions and this correlates with defective autophagic flux as measured by decreased accumulation of the early autophagy marker LC3-II. This work therefore highlights IL-1b blockade as a therapeutic option for patients with XIAP deficiency experiencing recurrent HLH and identifies a critical role for XIAP in promoting autophagy as a means of limiting IL-1b-mediated hyperinflammation during periods of cellular stress.

4.
bioRxiv ; 2024 May 15.
Article in English | MEDLINE | ID: mdl-38798384

ABSTRACT

The flaviviral NS2B/NS3 protease is a conserved enzyme required for flavivirus replication. Its highly dynamic conformation poses major challenges but also offers opportunities for antiviral inhibition. Here, we established a nanopore tweezers-based platform to monitor NS2B/NS3 conformational dynamics in real-time. Molecular simulations coupled with electrophysiology revealed that the protease could be captured in the middle of the ClyA nanopore lumen, stabilized mainly by dynamic electrostatic interactions. We designed a new Salmonella typhi ClyA nanopore with enhanced nanopore/protease interaction that can resolve the open and closed states at the single-molecule level for the first time. We demonstrated that the tailored ClyA could track the conformational transitions of the West Nile NS2B/NS3 protease and unravel the conformational energy landscape of various protease constructs through population and kinetic analysis. The new ClyA-protease platform paves a way to high-throughput screening strategies for discovering new allosteric inhibitors that target the NS2B and NS3 interface.

5.
Atherosclerosis ; : 117518, 2024 Mar 22.
Article in English | MEDLINE | ID: mdl-38627162

ABSTRACT

BACKGROUND AND AIMS: There are a limited number of pharmacologic therapies for coronary artery disease, and few rodent models of occlusive coronary atherosclerosis and consequent myocardial infarction with which one can rapidly test new therapeutic approaches. Here, we characterize a novel, fertile, and easy-to-use HDL receptor (SR-B1)-based model of atherogenic diet-inducible, fatal coronary atherosclerosis, the SR-B1ΔCT/LDLR KO mouse. Additionally, we test intramyocardial injection of Stromal Cell-Derived Factor-1 alpha (SDF-1α), a potent angiogenic cytokine, as a possible therapy to rescue cardiac function in this mouse. METHODS: SR-B1ΔCT/LDLR KO mice were fed the Paigen diet or standard chow diet, and we determined the effects of the diets on cardiac function, histology, and survival. After two weeks of feeding either the Paigen diet (n = 24) or standard chow diet (n = 20), the mice received an intramyocardial injection of either SDF-1α or phosphate buffered saline (PBS). Cardiac function and angiogenesis were assessed two weeks later. RESULTS: When six-week-old mice were fed the Paigen diet, they began to die as early as 19 days later and 50% had died by 38 days. None of the mice maintained on the standard chow diet died by day 72. Hearts from mice on the Paigen diet showed evidence of cardiomegaly, myocardial infarction, and occlusive coronary artery disease. For the five mice that survived until day 28 that underwent an intramyocardial injection of PBS on day 15, the average ejection fraction (EF) decreased significantly from day 14 (the day before injection, 52.1 ± 4.3%) to day 28 (13 days after the injection, 30.6 ± 6.8%) (paired t-test, n = 5, p = 0.0008). Of the 11 mice fed the Paigen diet and injected with SDF-1α on day 15, 8 (72.7%) survived to day 28. The average EF for these 8 mice increased significantly from 48.2 ± 7.2% on day 14 to63.6 ± 6.9% on day 28 (Paired t-test, n = 8, p = 0.003). CONCLUSIONS: This new mouse model and treatment with the promising angiogenic cytokine SDF-1α may lead to new therapeutic approaches for ischemic heart disease.

6.
Chem Commun (Camb) ; 60(40): 5298-5301, 2024 May 14.
Article in English | MEDLINE | ID: mdl-38660776

ABSTRACT

We demonstrate that an ionic liquid 1-ethyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide combined with propylene carbonate and lithium bis(trifluoromethanesulfonyl)imide yields a hybrid electrolyte that enables a wide operational temperature window (-20 °C to 60 °C). When integrated into a lithium titanate‖lithium cobalt oxide full-cell configuration, high-rate capability is achieved at -20 °C with >40% retention at a C/2 cycling rate, and negligible capacity fade is observed during rate capability tests and long-term cycling at 60 °C.

7.
Sleep Health ; 2024 Mar 27.
Article in English | MEDLINE | ID: mdl-38548566

ABSTRACT

INTRODUCTION: Insomnia symptoms are associated with poor physical and mental health. Exercise is associated with good sleep while sedentary behavior is associated with poor sleep. This study investigated the longitudinal, dynamic associations among exercise, sedentary behavior, and insomnia symptoms. METHODS: Seven hundred and fifty-six adults (Mage=47.2years, 54.9% female) took part in an online longitudinal study investigating sleep and health across the lifespan. Participants reported duration of moderate-to-strenuous exercise, percentage of day spent sitting, and insomnia symptoms (Insomnia Severity Index [ISI]). The ISI was scored as a total score and two-factor scores: (1) Sleep Disturbance (items 1, 2, 3) and (2) Daytime Dysfunction (items 4, 5, 6, 7). Multilevel modeling was used to examine the typical (i.e., between-persons) and individual (i.e., within-persons) associations among sedentary behavior, exercise, and insomnia symptoms. RESULTS: Sedentary behavior was significantly associated with total ISI scores at both the between-person and within-person levels (ß = 0.036, t = 3.23, p = .001; ß = 0.014, t = 1.99, p = .048). Both between-persons and within-person levels of sedentary behavior were associated with Daytime Dysfunction (ß = 0.028, t = 3.79, p < .001; ß = 0.009, t = 2.08, p = .039). Exercise was associated with total ISI and Daytime Dysfunction scores at the between-persons level but not at the within-persons level (ß = 0.028, t = 2.57, p = .01; ß = -0.002, t = -3.02, p = .003). CONCLUSIONS: Sedentary behavior was a more consistent and robust predictor of insomnia symptoms than exercise. The association between sedentary behavior and insomnia symptoms was dynamic in that when an individual reported being more sedentary than their norm, they also reported more insomnia symptoms. Future analyses should examine potential moderator variables and comorbid conditions.

8.
J Pers Med ; 14(3)2024 Mar 07.
Article in English | MEDLINE | ID: mdl-38541029

ABSTRACT

Molecular imaging is a key tool in the diagnosis and treatment of prostate cancer (PCa). Magnetic Resonance (MR) plays a major role in this respect with nuclear medicine imaging, particularly, Prostate-Specific Membrane Antigen-based, (PSMA-based) positron emission tomography with computed tomography (PET/CT) also playing a major role of rapidly increasing importance. Another key technology finding growing application across medicine and specifically in molecular imaging is the use of machine learning (ML) and artificial intelligence (AI). Several authoritative reviews are available of the role of MR-based molecular imaging with a sparsity of reviews of the role of PET/CT. This review will focus on the use of AI for molecular imaging for PCa. It will aim to achieve two goals: firstly, to give the reader an introduction to the AI technologies available, and secondly, to provide an overview of AI applied to PET/CT in PCa. The clinical applications include diagnosis, staging, target volume definition for treatment planning, outcome prediction and outcome monitoring. ML and AL techniques discussed include radiomics, convolutional neural networks (CNN), generative adversarial networks (GAN) and training methods: supervised, unsupervised and semi-supervised learning.

9.
Synth Syst Biotechnol ; 9(2): 250-258, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38435708

ABSTRACT

Methanotrophic bacteria are currently used industrially for the bioconversion of methane-rich natural gas and anaerobic digestion-derived biogas to valuable products. These bacteria may also serve to mitigate the negative effects of climate change by capturing atmospheric greenhouse gases. Several genetic tools have previously been developed for genetic and metabolic engineering of methanotrophs. However, the available tools for use in methanotrophs are significantly underdeveloped compared to many other industrially relevant bacteria, which hinders genetic and metabolic engineering of these biocatalysts. As such, expansion of the methanotroph genetic toolbox is needed to further our understanding of methanotrophy and develop biotechnologies that leverage these unique microbes for mitigation and conversion of methane to valuable products. Here, we determined the copy number of three broad-host-range plasmids in Methylococcus capsulatus Bath and Methylosinus trichosporium OB3b, representing phylogenetically diverse Gammaproteobacterial and Alphaproteobacterial methanotrophs, respectively. Further, we show that the commonly used synthetic Anderson series promoters are functional and exhibit similar relative activity in M. capsulatus and M. trichosporium OB3b, but the synthetic series had limited range. Thus, we mutagenized the native M. capsulatus particulate methane monooxygenase promoter and identified variants with activity that expand the activity range of synthetic, constitutive promoters functional not only in M. capsulatus, but also in Escherichia coli. Collectively, the tools developed here advance the methanotroph genetic engineering toolbox and represent additional synthetic genetic parts that may have broad applicability in Pseudomonadota bacteria.

10.
Dev Cell ; 59(7): 853-868.e7, 2024 Apr 08.
Article in English | MEDLINE | ID: mdl-38359833

ABSTRACT

Phagocytes remove dead and dying cells by engaging "eat-me" ligands such as phosphatidylserine (PtdSer) on the surface of apoptotic targets. However, PtdSer is obscured by the bulky exofacial glycocalyx, which also exposes ligands that activate "don't-eat-me" receptors such as Siglecs. Clearly, unshielding the juxtamembrane "eat-me" ligands is required for the successful engulfment of apoptotic cells, but the mechanisms underlying this process have not been described. Using human and murine cells, we find that apoptosis-induced retraction and weakening of the cytoskeleton that anchors transmembrane proteins cause an inhomogeneous redistribution of the glycocalyx: actin-depleted blebs emerge, lacking the glycocalyx, while the rest of the apoptotic cell body retains sufficient actin to tether the glycocalyx in place. Thus, apoptotic blebs can be engaged by phagocytes and are targeted for engulfment. Therefore, in cells with an elaborate glycocalyx, such as mucinous cancer cells, this "don't-come-close-to-me" barrier must be removed to enable clearance by phagocytosis.


Subject(s)
Actins , Glycocalyx , Animals , Humans , Mice , Glycocalyx/metabolism , Actins/metabolism , Phagocytes , Phagocytosis/physiology , Ligands , Apoptosis/physiology , Phosphatidylserines/metabolism
11.
Cancers (Basel) ; 16(3)2024 Feb 02.
Article in English | MEDLINE | ID: mdl-38339394

ABSTRACT

Performing a mitosis count (MC) is the diagnostic task of histologically grading canine Soft Tissue Sarcoma (cSTS). However, mitosis count is subject to inter- and intra-observer variability. Deep learning models can offer a standardisation in the process of MC used to histologically grade canine Soft Tissue Sarcomas. Subsequently, the focus of this study was mitosis detection in canine Perivascular Wall Tumours (cPWTs). Generating mitosis annotations is a long and arduous process open to inter-observer variability. Therefore, by keeping pathologists in the loop, a two-step annotation process was performed where a pre-trained Faster R-CNN model was trained on initial annotations provided by veterinary pathologists. The pathologists reviewed the output false positive mitosis candidates and determined whether these were overlooked candidates, thus updating the dataset. Faster R-CNN was then trained on this updated dataset. An optimal decision threshold was applied to maximise the F1-score predetermined using the validation set and produced our best F1-score of 0.75, which is competitive with the state of the art in the canine mitosis domain.

12.
Orthop Clin North Am ; 55(2): 171-180, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38403364

ABSTRACT

Periprosthetic joint infections (PJIs) are a devastating complication of joint arthroplasty surgeries that are often complicated by biofilm formation. The development of biofilms makes PJI treatment challenging as they create a barrier against antibiotics and host immune responses. This review article provides an overview of the current understanding of biofilm formation, factors that contribute to their production, and the most common organisms involved in this process. This article focuses on the identification of biofilms, as well as current methodologies and emerging therapies in the management of biofilms in PJI.


Subject(s)
Arthritis, Infectious , Prosthesis-Related Infections , Humans , Prosthesis-Related Infections/drug therapy , Biofilms , Arthritis, Infectious/etiology , Arthritis, Infectious/therapy , Anti-Bacterial Agents/therapeutic use , Arthroplasty
13.
Phys Rev E ; 109(1-1): 014606, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38366395

ABSTRACT

Active nematics are an important new paradigm in soft condensed matter systems. They consist of rodlike components with an internal driving force pushing them out of equilibrium. The resulting fluid motion exhibits chaotic advection, in which a small patch of fluid is stretched exponentially in length. Using simulation, this paper shows that this system can exhibit stable periodic motion when confined to a sufficiently small square with periodic boundary conditions. Moreover, employing tools from braid theory, we show that this motion is maximally mixing, in that it optimizes the (dimensionless) "topological entropy"-the exponential stretching rate of a material line advected by the fluid. That is, this periodic motion of the defects, counterintuitively, produces more chaotic mixing than chaotic motion of the defects. We also explore the stability of the periodic state. Importantly, we show how to stabilize this orbit into a larger periodic tiling, a critical necessity for it to be seen in future experiments.

14.
Proc Natl Acad Sci U S A ; 121(8): e2309465121, 2024 Feb 20.
Article in English | MEDLINE | ID: mdl-38354262

ABSTRACT

Phagocytes promptly resolve ingested targets to replenish lysosomes and maintain their responsiveness. The resolution process requires that degradative hydrolases, solute transporters, and proteins involved in lipid traffic are delivered and made active in phagolysosomes. It also involves extensive membrane remodeling. We report that cation channels that localize to phagolysosomes were essential for resolution. Specifically, the conductance of Na+ by two-pore channels (TPCs) and the presence of a Na+ gradient between the phagolysosome lumen and the cytosol were critical for the controlled release of membrane tension that permits deformation of the limiting phagolysosome membrane. In turn, membrane deformation was a necessary step to efficiently transport the cholesterol extracted from cellular targets, permeabilizing them to hydrolases. These results place TPCs as regulators of endomembrane remodeling events that precede target degradation in cases when the target is bound by a cholesterol-containing membrane. The findings may help to explain lipid metabolism dysfunction and autophagic flux impairment reported in TPC KO mice and establish stepwise regulation to the resolution process that begins with lysis of the target.


Subject(s)
Phagosomes , Two-Pore Channels , Mice , Animals , Phagosomes/metabolism , Lysosomes/metabolism , Hydrolases/metabolism , Cholesterol/metabolism
15.
Vet Microbiol ; 291: 110008, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38364465

ABSTRACT

Mycoplasma gallisepticum infection in poultry leads to disease and pathology that can reduce producer profits. Live attenuated vaccines are available that can limit or completely prevent the effects of infection. Field isolates that are genetically related to the attenuated vaccine strains have been isolated, raising the question of whether the attenuation of the vaccine strains is limited and can lead the strains to revert to more virulent forms. The 6/85 live attenuated vaccine is derived from a field isolate collected in the United States. Analysis of the genome of sequenced M. gallisepticum strains revealed a cluster of 10 6/85-like strains that group with the 6/85 vaccine strain. Four genomic regions were identified that allowed for strain differentiation. The genetic differences between strains points toward nine of the ten strains most likely being sister strains to the 6/85 vaccine strain. Insufficient differences are present in the tenth strain to make a definitive conclusion. These results suggest that most if not all strains similar to the live attenuated vaccine strain are field isolates of the parent strain used to derive the live attenuated vaccine.


Subject(s)
Mycoplasma Infections , Mycoplasma gallisepticum , Poultry Diseases , Animals , Vaccines, Attenuated , Bacterial Vaccines/genetics , Chickens , Poultry Diseases/prevention & control , Mycoplasma Infections/prevention & control , Mycoplasma Infections/veterinary
16.
Int J Med Robot ; 20(1): e2621, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38348740

ABSTRACT

BACKGROUND: Large language models (LLM) have unknown implications for medical research. This study assessed whether LLM-generated abstracts are distinguishable from human-written abstracts and to compare their perceived quality. METHODS: The LLM ChatGPT was used to generate 20 arthroplasty abstracts (AI-generated) based on full-text manuscripts, which were compared to originally published abstracts (human-written). Six blinded orthopaedic surgeons rated abstracts on overall quality, communication, and confidence in the authorship source. Authorship-confidence scores were compared to a test value representing complete inability to discern authorship. RESULTS: Modestly increased confidence in human authorship was observed for human-written abstracts compared with AI-generated abstracts (p = 0.028), though AI-generated abstract authorship-confidence scores were statistically consistent with inability to discern authorship (p = 0.999). Overall abstract quality was higher for human-written abstracts (p = 0.019). CONCLUSIONS: AI-generated abstracts' absolute authorship-confidence ratings demonstrated difficulty in discerning authorship but did not achieve the perceived quality of human-written abstracts. Caution is warranted in implementing LLMs into scientific writing.


Subject(s)
Artificial Intelligence , Authorship , Humans , Communication , Language , Arthroplasty
17.
BMJ Open ; 14(1): e079863, 2024 01 22.
Article in English | MEDLINE | ID: mdl-38262635

ABSTRACT

INTRODUCTION: Worldwide, pancreatic cancer has a poor prognosis. Early diagnosis may improve survival by enabling curative treatment. Statistical and machine learning diagnostic prediction models using risk factors such as patient demographics and blood tests are being developed for clinical use to improve early diagnosis. One example is the Enriching New-onset Diabetes for Pancreatic Cancer (ENDPAC) model, which employs patients' age, blood glucose and weight changes to provide pancreatic cancer risk scores. These values are routinely collected in primary care in the UK. Primary care's central role in cancer diagnosis makes it an ideal setting to implement ENDPAC but it has yet to be used in clinical settings. This study aims to determine the feasibility of applying ENDPAC to data held by UK primary care practices. METHODS AND ANALYSIS: This will be a multicentre observational study with a cohort design, determining the feasibility of applying ENDPAC in UK primary care. We will develop software to search, extract and process anonymised data from 20 primary care providers' electronic patient record management systems on participants aged 50+ years, with a glycated haemoglobin (HbA1c) test result of ≥48 mmol/mol (6.5%) and no previous abnormal HbA1c results. Software to calculate ENDPAC scores will be developed, and descriptive statistics used to summarise the cohort's demographics and assess data quality. Findings will inform the development of a future UK clinical trial to test ENDPAC's effectiveness for the early detection of pancreatic cancer. ETHICS AND DISSEMINATION: This project has been reviewed by the University of Surrey University Ethics Committee and received a favourable ethical opinion (FHMS 22-23151 EGA). Study findings will be presented at scientific meetings and published in international peer-reviewed journals. Participating primary care practices, clinical leads and policy makers will be provided with summaries of the findings.


Subject(s)
Diabetes Mellitus , Pancreatic Neoplasms , Humans , Feasibility Studies , Glycated Hemoglobin , Observational Studies as Topic , Primary Health Care , Risk Factors , Middle Aged , Multicenter Studies as Topic , Aged
18.
J Arthroplasty ; 2024 Jan 26.
Article in English | MEDLINE | ID: mdl-38280615

ABSTRACT

BACKGROUND: Liver cirrhosis is associated with increased perioperative morbidity. Our study used the Model for End-Stage Liver Disease (MELD) score to assess the impact of cirrhosis severity on postoperative outcomes following total knee arthroplasty (TKA). METHODS: A retrospective review identified 59 patients with liver cirrhosis who underwent primary TKA at a large, urban, academic center from January 2013 to August 2022. Cirrhosis was categorized as mild (MELD < 10; n = 47) or moderate-severe (MELD ≥ 10; n = 12). Modified Clavien-Dindo classification was used to grade complications, where grade 2+ denoted significant intervention. Hospital length of stay, nonhome discharge, and mortality were collected. A 1:1 propensity matching was used to control for demographics and selected comorbidities. RESULTS: Moderate-severe cirrhosis was associated with significantly higher rates of intrahospital overall (58.33 versus 16.67%, P = .036) complications, 30-day overall complications (75 versus 33.33%, P = .042), and 90-day overall complications (75 versus 33.33%, P = .042) when compared to matched mild cirrhosis patients. Compared to matched noncirrhotic controls, mild cirrhosis patients had no significant increase in complication rate or other outcomes (P > .05). CONCLUSIONS: Patients with moderate-severe liver cirrhosis are at risk of short-term complications following primary TKA. Patients with mild cirrhosis have comparable outcomes to matched noncirrhotic patients. Surgeons can use MELD score prior to scheduling TKA to determine which patients require optimization or higher levels of perioperative care.

19.
Org Lett ; 26(2): 488-492, 2024 Jan 19.
Article in English | MEDLINE | ID: mdl-38197784

ABSTRACT

The indolizidine core of virosinine A was synthesized by means of a microwave-promoted cascade reaction featuring 5-exo-trig iminyl radical cyclization, thiyl radical elimination, and intramolecular imine alkylation. The resulting bicyclic iminium ion underwent stereoselective reduction by Red-Al to deliver the target compound. DFT calculations suggested that both the radical cyclization and thiyl radical elimination steps are reversible at high reaction temperatures.

20.
Eur J Cell Biol ; 103(1): 151382, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38171214

ABSTRACT

The ongoing phagocytic activity of macrophages necessitates an extraordinary capacity to digest and resolve incoming material. While the initial steps leading to the formation of a terminal phagolysosome are well studied, much less is known about the later stages of this process, namely the degradation and resolution of the phagolysosomal contents. We report that the degradation of targets such as splenocytes and erythrocytes by phagolysosomes occurs in a stepwise fashion, requiring lysis of their plasmalemmal bilayer as an essential initial step. This is achieved by the direct extraction of cholesterol facilitated by Niemann-Pick protein type C2 (NPC2), which in turn hands off cholesterol to NPC1 for export from the phagolysosome. The removal of cholesterol ulimately destabilizes and permeabilizes the membrane of the phagocytic target, allowing access of hydrolases to its internal compartments. In contrast, we found that saposins, which activate the hydrolysis of sphingolipids, are required for lysosomal tubulation, yet are dispensable for the resolution of targets by macrophages. The extraction of cholesterol by NPC2 is therefore envisaged as rate-limiting in the clearance of membrane-bound targets such as apoptotic cells. Selective cholesterol removal appears to be a primary mechanism that enables professional phagocytes to distinguish the target membrane from the phagolysosomal membrane and may be conserved in the resolution of autolysosomes.


Subject(s)
Glycoproteins , Membrane Glycoproteins , Glycoproteins/metabolism , Membrane Glycoproteins/metabolism , Carrier Proteins/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Vesicular Transport Proteins/metabolism , Cholesterol/metabolism , Phagosomes/metabolism , Lysosomes/metabolism
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