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1.
Phys Rev Lett ; 132(26): 266505, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38996298

RESUMO

The properties of kagome metals are governed by the interdependence of band topology and electronic correlations resulting in remarkably rich phase diagrams. Here, we study the temperature evolution of the bulk electronic structure of the antiferromagnetic kagome metal FeGe using infrared spectroscopy. We uncover drastic changes in the low-energy interband absorption at the 100 K structural phase transition that has been linked to a charge-density-wave (CDW) instability. We explain this effect by the minuscule Fe displacement in the kagome plane, which results in parallel bands in the vicinity of the Fermi level. In contrast to conventional CDW materials, however, the spectral weight shifts to low energies, ruling out the opening of a CDW gap in FeGe.

2.
Cell Rep ; 43(7): 114452, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38968068

RESUMO

Macrophages are effector immune cells that experience substantial changes to oxygenation when transiting through tissues, especially when entering tumors or infected wounds. How hypoxia alters gene expression and macrophage effector function at the post-transcriptional level remains poorly understood. Here, we use TimeLapse-seq to measure how inflammatory activation modifies the hypoxic response in primary macrophages. Nucleoside recoding sequencing allows the derivation of steady-state transcript levels, degradation rates, and transcriptional synthesis rates from the same dataset. We find that hypoxia produces distinct responses from resting and inflammatory macrophages. Hypoxia induces destabilization of mRNA transcripts, though inflammatory macrophages substantially increase mRNA degradation compared to resting macrophages. Increased RNA turnover results in the upregulation of ribosomal protein genes and downregulation of extracellular matrix components in inflammatory macrophages. Pathways regulated by mRNA decay in vitro are differentially regulated in tumor-associated macrophages implying that mixed stimuli could induce post-transcriptional regulation of macrophage function in solid tumors.

3.
Artigo em Inglês | MEDLINE | ID: mdl-38915286

RESUMO

Extracellular matrix (ECM) remodeling has been implicated in the irreversible obstruction of airways and destruction of alveolar tissue in chronic obstructive pulmonary disease (COPD). Studies investigating differences in the lung ECM in COPD have mainly focused on some collagens and elastin, leaving an array of ECM components unexplored. We investigated the differences in the ECM landscape comparing severe-early onset (SEO-) COPD and moderate COPD to control lung tissue for collagen type I α chain 1 (COL1A1), COL6A1, COL6A2, COL14A1, fibulin 2 and 5 (FBLN2, FBLN5), latent transforming growth factor-beta binding protein 4 (LTBP4), lumican (LUM), versican (VCAN), decorin (DCN), and elastin (ELN) using image analysis and statistical modelling. Percentage area and/or mean intensity of expression of LUM in the parenchyma, and COL1A1, FBLN2, LTBP4, DCN, and VCAN in the airway walls, was proportionally lower in COPD compared to controls. Lowered levels of most ECM proteins were associated with decreasing FEV1 measurements, indicating a relationship with disease severity. Furthermore, we identified six unique ECM signatures where LUM and COL6A1 in parenchyma and COL1A1, FBLN5, DCN, and VCAN in airway walls appear essential in reflecting the presence and severity of COPD. These signatures emphasize the need to examine groups of proteins to represent an overall difference in the ECM landscape in COPD, that are more likely to be related to functional effects, than individual proteins. Our study revealed differences in the lung ECM landscape between control and COPD and between SEO and moderate COPD signifying distinct pathological processes in the different subgroups.

4.
Eur J Haematol ; 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38780264

RESUMO

BACKGROUND: This study aimed to determine whether implementing a rapid response system (RRS) is associated with improved short-term outcomes in critically ill patients with haematological malignancies. METHODS: Our monocentric pre- versus post-intervention study was conducted between January 2012 and April 2020. RRS was activated at early signs of haemodynamic or respiratory failure. The primary outcome was the reduction in Sequential Organ Failure Assessment (SOFA) score on Day 3 after intensive care unit (ICU) admission. Secondary outcomes included time to ICU admission and mortality. RESULTS: A total of 209 patients with a median age of 59 years were enrolled (108 in the pre-intervention period and 101 in the post-intervention period). 22% of them had received an allogeneic transplant. The post-intervention period was associated with a shorter time to ICU admission (195 vs. 390 min, p < .001), a more frequent favourable trend in SOFA score (57% vs. 42%, adjusted odds ratio, 2.02, 95% confidence interval, 1.09 to 3.76), no significant changes in ICU (22% vs. 26%, p = .48) and 1-year (62% vs. 58%, p = .62) mortality rates. CONCLUSION: Detection of early organ failure and activation of an RRS was associated with faster ICU admission and lower SOFA scores on Day 3 of admission in critically ill patients with haematological malignancies.

5.
Public Health ; 226: 84-90, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38016200

RESUMO

OBJECTIVES: The association between asthma and COVID-19 mortality remains inconclusive. We examined the association between asthma and clinical outcomes of patients with COVID-19. STUDY DESIGN: A case-control study based on a surveillance cohort in Harris County, Texas. METHODS: Using the data of 21,765 patients who reported having at least one chronic health condition, we investigated the association between asthma and COVID-19 severity, characterized primarily by hospitalization and death. Unconditional logistic regression models were used to estimate the multivariable odds ratio (mOR) and its 95 % confidence interval (CI) of COVID-19 severity associated with asthma and other chronic lung diseases, adjusting for demographic and other comorbidities. A P-value < 0.005 was considered statistically significant after correcting multiple testing. RESULTS: In total, 3034 patients (13.9 %) had asthma, and 774 (3.56 %) had other chronic lung diseases. The case death rate among patients with asthma and other chronic lung diseases was 0.75 % and 19.0 %, respectively. Compared to patients without the respective conditions, patients with asthma had lower odds of death (mOR = 0.44, 95 % CI: 0.27-0.69), while patients with other chronic lung diseases had higher odds of hospitalization (mOR = 2.02, 95 % CI: 1.68-2.42) and death (mOR = 1.95, 95 % CI: 1.52-2.49) (P-values < 0.005). Risk factors for COVID-19 mortality included older age, male gender, diabetes, obesity, hypertension, cardiovascular disease, active cancer, and chronic kidney disease. CONCLUSIONS: The public health surveillance data suggested that preexisting asthma was inversely associated with COVID-19 mortality.


Assuntos
Asma , COVID-19 , Humanos , Masculino , COVID-19/epidemiologia , Comorbidade , Estudos de Casos e Controles , SARS-CoV-2 , Asma/epidemiologia , Fatores de Risco , Hospitalização , Estudos Retrospectivos
6.
Int Forum Allergy Rhinol ; 14(2): 149-608, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37658764

RESUMO

BACKGROUND: Sinonasal neoplasms, whether benign and malignant, pose a significant challenge to clinicians and represent a model area for multidisciplinary collaboration in order to optimize patient care. The International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors (ICSNT) aims to summarize the best available evidence and presents 48 thematic and histopathology-based topics spanning the field. METHODS: In accordance with prior International Consensus Statement on Allergy and Rhinology documents, ICSNT assigned each topic as an Evidence-Based Review with Recommendations, Evidence-Based Review, and Literature Review based on the level of evidence. An international group of multidisciplinary author teams were assembled for the topic reviews using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses format, and completed sections underwent a thorough and iterative consensus-building process. The final document underwent rigorous synthesis and review prior to publication. RESULTS: The ICSNT document consists of four major sections: general principles, benign neoplasms and lesions, malignant neoplasms, and quality of life and surveillance. It covers 48 conceptual and/or histopathology-based topics relevant to sinonasal neoplasms and masses. Topics with a high level of evidence provided specific recommendations, while other areas summarized the current state of evidence. A final section highlights research opportunities and future directions, contributing to advancing knowledge and community intervention. CONCLUSION: As an embodiment of the multidisciplinary and collaborative model of care in sinonasal neoplasms and masses, ICSNT was designed as a comprehensive, international, and multidisciplinary collaborative endeavor. Its primary objective is to summarize the existing evidence in the field of sinonasal neoplasms and masses.


Assuntos
Neoplasias de Cabeça e Pescoço , Hipersensibilidade , Neoplasias dos Seios Paranasais , Humanos , Qualidade de Vida , Neoplasias dos Seios Paranasais/terapia , Neoplasias dos Seios Paranasais/patologia
7.
ArXiv ; 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-38076514

RESUMO

Electron cryomicroscopy (cryo-EM) is an imaging technique widely used in structural biology to determine the three-dimensional structure of biological molecules from noisy two-dimensional projections with unknown orientations. As the typical pipeline involves processing large amounts of data, efficient algorithms are crucial for fast and reliable results. The stochastic gradient descent (SGD) algorithm has been used to improve the speed of ab initio reconstruction, which results in a first, low-resolution estimation of the volume representing the molecule of interest, but has yet to be applied successfully in the high-resolution regime, where expectation-maximization algorithms achieve state-of-the-art results, at a high computational cost. In this article, we investigate the conditioning of the optimization problem and show that the large condition number prevents the successful application of gradient descent-based methods at high resolution. Our results include a theoretical analysis of the condition number of the optimization problem in a simplified setting where the individual projection directions are known, an algorithm based on computing a diagonal preconditioner using Hutchinson's diagonal estimator, and numerical experiments showing the improvement in the convergence speed when using the estimated preconditioner with SGD. The preconditioned SGD approach can potentially enable a simple and unified approach to ab initio reconstruction and high-resolution refinement with faster convergence speed and higher flexibility, and our results are a promising step in this direction.

8.
Protein Sci ; 32(11): e4806, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37833244

RESUMO

Bacterial WxL proteins contain peptidoglycan-binding WxL domains, which have a dual Trp-x-Leu motif and are involved in virulence. It was recently shown that WxL proteins occur in gene clusters, containing typically a small WxL protein (which in the mature protein consists only of a WxL domain), a large WxL protein (which contains a C-terminal WxL domain with N-terminal host-binding domains), and a conserved protein annotated as a Domain of Unknown Function (DUF). Here we analyze this DUF and show that it contains two tandem domains-DUF916 and DUF3324-which both have an IgG-like fold and together form a single functional unit, connected to a C-terminal transmembrane helix. DUF3324 is a stable domain, while DUF916 is less stable and is likely to require a stabilizing interaction with WxL. The protein is suggested to have an important role to bind and stabilize WxL on the peptidoglycan surface, via the DUF916 domain, and to bind to host cells via the DUF3324 domain. AlphaFold2 predicts that a ß-hairpin strand from DUF916 inserts into WxL adjacent to its N-terminus. We therefore propose to rename the DUF916-DUF3324 pair as WxL Interacting Protein (WxLIP), with DUF916, DUF3324 and the transmembrane helix forming the first, second and third domains of WxLIP, which we characterize as peptidoglycan binding domain (PGBD), host binding domain (HBD), and transmembrane helix (TMH) respectively.


Assuntos
Proteínas de Bactérias , Peptidoglicano , Peptidoglicano/metabolismo , Proteínas de Bactérias/química , Ligação Proteica , Virulência
9.
Rev Mal Respir ; 40(8): 692-699, 2023 Oct.
Artigo em Francês | MEDLINE | ID: mdl-37659881

RESUMO

In medicine, each decision is the result of a trade-off between medical scientific data, the rights of individuals (protection of persons, information, consent), individual desires, collective values and norms, and the economic constraints that guide our society. Whether or not to admit a cancer patient to an intensive care unit is very often an ethical dilemma. It is necessary to distinguish patients who would benefit from admission to an intensive care unit (ICU) from those for whom it would be futile. In this review, we will discuss the appropriateness of ICU admission and the concept of unreasonable admission, along with the different levels of intensity of ICU care and the alternatives to intensive care. We will then consider how and when to initiate reflection leading to a reasonable decision for the patient.

11.
PLoS Pathog ; 19(6): e1011015, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37384772

RESUMO

Clostridioides difficile is responsible for substantial morbidity and mortality in antibiotically-treated, hospitalised, elderly patients, in which toxin production correlates with diarrhoeal disease. While the function of these toxins has been studied in detail, the contribution of other factors, including the paracrystalline surface layer (S-layer), to disease is less well understood. Here, we highlight the essentiality of the S-layer in vivo by reporting the recovery of S-layer variants, following infection with the S-layer-null strain, FM2.5. These variants carry either correction of the original point mutation, or sequence modifications which restored the reading frame, and translation of slpA. Selection of these variant clones was rapid in vivo, and independent of toxin production, with up to 90% of the recovered C. difficile population encoding modified slpA sequence within 24 h post infection. Two variants, subsequently named FM2.5varA and FM2.5varB, were selected for study in greater detail. Structural determination of SlpA from FM2.5varB indicated an alteration in the orientation of protein domains, resulting in a reorganisation of the lattice assembly, and changes in interacting interfaces, which might alter function. Interestingly, variant FM2.5varB displayed an attenuated, FM2.5-like phenotype in vivo compared to FM2.5varA, which caused disease severity more comparable to that of R20291. Comparative RNA sequencing (RNA-Seq) analysis of in vitro grown isolates revealed large changes in gene expression between R20291 and FM2.5. Downregulation of tcdA/tcdB and several genes associated with sporulation and cell wall integrity may account for the reported attenuated phenotype of FM2.5 in vivo. RNA-seq data correlated well with disease severity with the more virulent variant, FM2.5varA, showing s similar profile of gene expression to R20291 in vitro, while the attenuated FM2.5varB showed downregulation of many of the same virulence associated traits as FM2.5. Cumulatively, these data add to a growing body of evidence that the S-layer contributes to C. difficile pathogenesis and disease severity.


Assuntos
Toxinas Bacterianas , Clostridioides difficile , Clostridioides , Clostridioides difficile/genética , Parede Celular , Células Clonais
12.
Aquat Toxicol ; 260: 106584, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37267806

RESUMO

Estrogenic endocrine disrupting chemicals (EEDC) have been suspected to impact offspring in a transgenerational manner via modifications of the germline epigenome in the directly exposed generations. A holistic assessment of the concentration/ exposure duration-response, threshold level, and critical exposure windows (parental gametogenesis and embryogenesis) for the transgenerational evaluation of reproduction and immune compromise concomitantly will inform the overall EEDC exposure risk. We conducted a multigenerational study using the environmental estrogen, 17α-ethinylestradiol (EE2), and the marine laboratory model fish Oryzias melastigma (adult, F0) and their offspring (F1-F4) to identify transgenerationally altered offspring generations and phenotype persistence. Three exposure scenarios were used: short parental exposure, long parental exposure, and a combined parental and embryonic exposure using two concentrations of EE2 (33ng/L, 113ng/L). The reproductive fitness of fish was evaluated by assessing fecundity, fertilization rate, hatching success, and sex ratio. Immune competence was assessed in adults via a host-resistance assay. EE2 exposure during both parental gametogenesis and embryogenesis was found to induce concentration/ exposure duration-dependent transgenerational reproductive effects in the unexposed F4 offspring. Furthermore, embryonic exposure to 113 ng/L EE2 induced feminization of the directly exposed F1 generation, followed by subsequent masculinization of the F2 and F3 generations. A sex difference was found in the transgenerationally impaired reproductive output with F4 females being sensitive to the lowest concentration of EE2 (33 ng/L) upon long-term ancestral parent exposure (21 days). Conversely, F4 males were affected by ancestral embryonic EE2 exposure. No definitive transgenerational impacts on immune competence were identified in male or female offspring. In combination, these results indicate that EEDCs can be transgenerational toxicants that may negatively impact the reproductive success and population sustainability of fish populations.


Assuntos
Oryzias , Poluentes Químicos da Água , Animais , Feminino , Masculino , Oryzias/fisiologia , Aptidão Genética , Poluentes Químicos da Água/toxicidade , Reprodução , Fertilidade , Etinilestradiol/toxicidade
13.
Can Vet J ; 64(6): 545-548, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37265818

RESUMO

A 6-year-old neutered male bloodhound dog was presented for surgical evaluation of an intraoral hard palate mass noted during a routine dental cleaning performed by the primary veterinarian. Computed tomography (CT) of the skull revealed a well-defined, multilobular, mineralized mass with a coarse, granular appearance, centered along the palatomaxillary suture extending into both the nasal and oral cavities. Bilateral caudal maxillectomy was performed for curative-intent resection of the tumor. The histopathology of the mass was consistent with a completely excised palatomaxillary multilobular tumor of bone (MLTB). This is apparently the 1st successful report of surgical excision of an MLTB associated with the palatomaxillary suture line. Key clinical message: Our findings emphasized that MLTB should be considered as a differential diagnosis for masses arising in the location of cranial sutures, and a definitive diagnosis can be made postoperatively with histopathology of the mass.


Tumeur osseuse multi-lobulaire résultant de la ligne de suture palato-maxillaire dans le crâne d'un chien. Un chien Saint-Hubert mâle castré de 6 ans a été présenté pour évaluation chirurgicale d'une masse intrabuccale du palais dur notée lors d'un nettoyage dentaire de routine effectué par le vétérinaire initial. La tomodensitométrie (CT) du crâne a révélé une masse minéralisée multi-lobulaire bien définie avec un aspect grossier et granuleux, centrée le long de la suture palato-maxillaire s'étendant dans les cavités nasale et buccale. Une maxillectomie caudale bilatérale a été réalisée pour une résection à visée curative de la tumeur. L'histopathologie de la masse était compatible avec une tumeur osseuse multi-lobulaire palato-maxillaire complètement excisée (MLTB). Il s'agit apparemment du premier rapport réussi d'excision chirurgicale d'une MLTB associé à la ligne de suture palato-maxillaire.Message clinique clé :Nos résultats ont souligné que la MLTB doit être considérée comme un diagnostic différentiel pour les masses apparaissant à l'emplacement des sutures crâniennes, et un diagnostic définitif peut être posé en postopératoire avec l'histopathologie de la masse.(Traduit par Dr Serge Messier).


Assuntos
Neoplasias Ósseas , Doenças do Cão , Masculino , Cães , Animais , Suturas Cranianas , Crânio , Neoplasias Ósseas/veterinária , Suturas , Doenças do Cão/diagnóstico por imagem , Doenças do Cão/cirurgia
14.
PLoS One ; 18(6): e0287449, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37352285

RESUMO

Objective measures of adherence for antiretrovirals used as pre-exposure prophylaxis (PrEP) are critical for improving preventative efficacy in both clinical trials and real-world application. Current objective adherence measures either reflect only recent behavior (eg days for plasma or urine) or cumulative behavior (eg months for dried blood spots). Here, we measured the accumulation of the antiretroviral drug maraviroc (MVC) in hair strands by infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging (MSI) to evaluate adherence behavior longitudinally at high temporal resolution. An MSI threshold for classifying daily adherence was established using clinical samples from healthy volunteers following directly observed dosing of 1 to 7 doses MVC/week. We then used the benchmarked MSI assay to classify adherence to MVC-based PrEP regimens in hair samples collected throughout the 48-week HPTN069/ACTGA5305 study. We found that only ~32% of investigated hair samples collected during the study's active dosing period showed consistent daily PrEP adherence throughout a retrospective period of 30 days, and also found that profiles of daily individual adherence from MSI hair analysis could identify when patients were and were not taking study drug. The assessment of adherence from MSI hair strand analysis was 62% lower than adherence classified using paired plasma samples, the latter of which may be influenced by white-coat adherence. These findings demonstrate the ability of MSI hair analysis to examine daily variability of adherence behavior over a longer-term measurement and offer the potential for longitudinal comparison with risk behavior to target patient-specific adherence interventions and improve outcomes.


Assuntos
Fármacos Anti-HIV , Infecções por HIV , Profilaxia Pré-Exposição , Humanos , Maraviroc , Infecções por HIV/tratamento farmacológico , Infecções por HIV/prevenção & controle , Estudos Retrospectivos , Antirretrovirais/análise , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Cabelo/química , Adesão à Medicação , Profilaxia Pré-Exposição/métodos
15.
J Am Heart Assoc ; 12(10): e026950, 2023 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-37183873

RESUMO

Background Cardiac metabolic abnormalities are present in heart failure. Few studies have followed metabolic changes accompanying diastolic and systolic heart failure in the same model. We examined metabolic changes during the development of diastolic and severe systolic dysfunction in spontaneously hypertensive rats (SHR). Methods and Results We serially measured myocardial glucose uptake rates with dynamic 2-[18F] fluoro-2-deoxy-d-glucose positron emission tomography in vivo in 9-, 12-, and 18-month-old SHR and Wistar Kyoto rats. Cardiac magnetic resonance imaging determined systolic function (ejection fraction) and diastolic function (isovolumetric relaxation time) and left ventricular mass in the same rats. Cardiac metabolomics was performed at 12 and 18 months in separate rats. At 12 months, SHR hearts, compared with Wistar Kyoto hearts, demonstrated increased isovolumetric relaxation time and slightly reduced ejection fraction indicating diastolic and mild systolic dysfunction, respectively, and higher (versus 9-month-old SHR decreasing) 2-[18F] fluoro-2-deoxy-d-glucose uptake rates (Ki). At 18 months, only few SHR hearts maintained similar abnormalities as 12-month-old SHR, while most exhibited severe systolic dysfunction, worsening diastolic function, and markedly reduced 2-[18F] fluoro-2-deoxy-d-glucose uptake rates. Left ventricular mass normalized to body weight was elevated in SHR, more pronounced with severe systolic dysfunction. Cardiac metabolite changes differed between SHR hearts at 12 and 18 months, indicating progressive defects in fatty acid, glucose, branched chain amino acid, and ketone body metabolism. Conclusions Diastolic and severe systolic dysfunction in SHR are associated with decreasing cardiac glucose uptake, and progressive abnormalities in metabolite profiles. Whether and which metabolic changes trigger progressive heart failure needs to be established.


Assuntos
Insuficiência Cardíaca , Hipertensão , Ratos , Animais , Ratos Endogâmicos SHR , Tomografia Computadorizada por Raios X , Ratos Endogâmicos WKY , Glucose , Desoxiglucose , Pressão Sanguínea
16.
J Comp Pathol ; 202: 8-15, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37018925

RESUMO

Proliferative tenosynovitis (PT) is an inflammatory and proliferative disorder of the synovial membrane of the tendon sheath that is rare in animals. The histological alterations are characterized by multinodular neovascularization, with infiltration of histiocytic and multinucleated giant cells and haemosiderin deposition. We reviewed necropsy and biopsy records of horses submitted to the Setor de Anatomia Patológica of the Universidade Federal Rural do Rio de Janeiro from January 2017 to December 2020 to select cases of PT. We identified PT in three adult Brazilian Mangalarga Marchador horses with nodular lesions on the metacarpophalangeal, metatarsophalangeal or carpal joints. The three horses were under 6 years of age and presented with lameness and pain on palpation. There were recurrences in two horses after surgical removal. Radiographic and ultrasound examinations detected masses in the flexor or extensor tendons and subtendinous bursa. Histological study of synovial membrane and tendon sheath revealed an increased number of vessels, fibroplasia, osseous metaplasia and infiltration of lymphocytes, plasma cells and siderophages. This is the first description of PT in horses, which should be included as an orthopaedic differential diagnosis, especially in Mangalarga Marchador horses with lameness.


Assuntos
Doenças dos Cavalos , Tenossinovite , Cavalos , Animais , Tenossinovite/veterinária , Tenossinovite/diagnóstico , Tenossinovite/patologia , Coxeadura Animal/patologia , Coxeadura Animal/cirurgia , Brasil , Tendões , Doenças dos Cavalos/patologia
17.
J Mol Biol ; 435(9): 168020, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-36863660

RESUMO

Macromolecules change their shape (conformation) in the process of carrying out their functions. The imaging by cryo-electron microscopy of rapidly-frozen, individual copies of macromolecules (single particles) is a powerful and general approach to understanding the motions and energy landscapes of macromolecules. Widely-used computational methods already allow the recovery of a few distinct conformations from heterogeneous single-particle samples, but the treatment of complex forms of heterogeneity such as the continuum of possible transitory states and flexible regions remains largely an open problem. In recent years there has been a surge of new approaches for treating the more general problem of continuous heterogeneity. This paper surveys the current state of the art in this area.


Assuntos
Microscopia Crioeletrônica , Microscopia Crioeletrônica/métodos , Conformação Molecular , Movimento (Física)
18.
ArXiv ; 2023 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-36994155

RESUMO

Variational autoencoders (VAEs) are a popular generative model used to approximate distributions. The encoder part of the VAE is used in amortized learning of latent variables, producing a latent representation for data samples. Recently, VAEs have been used to characterize physical and biological systems. In this case study, we qualitatively examine the amortization properties of a VAE used in biological applications. We find that in this application the encoder bears a qualitative resemblance to more traditional explicit representation of latent variables.

19.
Am J Physiol Lung Cell Mol Physiol ; 324(4): L521-L535, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36808722

RESUMO

Lung fibroblasts are implicated in abnormal tissue repair in chronic obstructive pulmonary disease (COPD). The exact mechanisms are unknown and comprehensive analysis comparing COPD- and control fibroblasts is lacking. The aim of this study is to gain insight into the role of lung fibroblasts in COPD pathology using unbiased proteomic and transcriptomic analysis. Protein and RNA were isolated from cultured parenchymal lung fibroblasts of 17 patients with stage IV COPD and 16 non-COPD controls. Proteins were analyzed using LC-MS/MS and RNA through RNA sequencing. Differential protein and gene expression in COPD was assessed via linear regression, followed by pathway enrichment, correlation analysis, and immunohistological staining in lung tissue. Proteomic and transcriptomic data were compared to investigate the overlap and correlation between both levels of data. We identified 40 differentially expressed (DE) proteins and zero DE genes between COPD and control fibroblasts. The most significant DE proteins were HNRNPA2B1 and FHL1. Thirteen of the 40 proteins were previously associated with COPD, including FHL1 and GSTP1. Six of the 40 proteins were related to telomere maintenance pathways, and were positively correlated with the senescence marker LMNB1. No significant correlation between gene and protein expression was observed for the 40 proteins. We hereby describe 40 DE proteins in COPD fibroblasts including previously described COPD proteins (FHL1, GSTP1) and new COPD research targets like HNRNPA2B1. Lack of overlap and correlation between gene and protein data supports the use of unbiased proteomics analysis and indicates that different types of information are generated with both methods.


Assuntos
Proteômica , Doença Pulmonar Obstrutiva Crônica , Humanos , Cromatografia Líquida , Espectrometria de Massas em Tandem , Pulmão/metabolismo , Doença Pulmonar Obstrutiva Crônica/patologia , RNA/metabolismo , Fibroblastos/metabolismo , Proteínas Musculares/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas com Domínio LIM/metabolismo
20.
Reprod Toxicol ; 117: 108350, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36803739

RESUMO

Preterm birth (PTB) is associated with a high risk of infant mortality and long-term adverse health effects. Glyphosate is a broad-spectrum herbicide applied in agricultural and non-agricultural settings. Studies suggested an association between maternal exposure to glyphosate and PTB among mostly racially homogenous populations, though results were inconsistent. The objective of this pilot study was to inform the design of a larger and more definitive study of glyphosate exposure and adverse birth outcomes in a racially-diverse population. Urine was obtained from 26 women with a PTB as cases and 26 women with a term birth as controls, from participants enrolled in a birth cohort in Charleston, South Carolina. We used binomial logistic regression to estimate associations between urinary glyphosate and the odds of PTB, and multinomial regression to estimate associations between maternal racial identity and urinary glyphosate among controls. Glyphosate was unrelated to PTB (odds ratio (OR) = 1.06, 95% CI: 0.61, 1.86). Women who identified as Black had greater odds (OR = 3.83, 95% CI: 0.13, 111.33) of having categorical "high" glyphosate (> 0.28 ng/mL) and lesser odds (OR = 0.79, 95% CI: 0.05, 12.21) of "low" glyphosate (< 0.03 ng/mL) relative to women who identified as white, suggesting a potential racial disparity, although the effect estimates were imprecise and included the null. Given concerns of potential reproductive toxicity of glyphosate, the results merit confirmation in a larger investigation to determine specific sources of glyphosate exposure, incorporating longitudinal urinary glyphosate measures during pregnancy and a comprehensive measure of diet.


Assuntos
Nascimento Prematuro , Gravidez , Lactente , Recém-Nascido , Humanos , Feminino , Nascimento Prematuro/epidemiologia , Projetos Piloto , Estudos de Casos e Controles , Glicina/toxicidade , Glifosato
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