Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
BMC Bioinformatics ; 25(1): 134, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38539070

RESUMO

Deep learning methods have emerged as powerful tools for analyzing histopathological images, but current methods are often specialized for specific domains and software environments, and few open-source options exist for deploying models in an interactive interface. Experimenting with different deep learning approaches typically requires switching software libraries and reprocessing data, reducing the feasibility and practicality of experimenting with new architectures. We developed a flexible deep learning library for histopathology called Slideflow, a package which supports a broad array of deep learning methods for digital pathology and includes a fast whole-slide interface for deploying trained models. Slideflow includes unique tools for whole-slide image data processing, efficient stain normalization and augmentation, weakly-supervised whole-slide classification, uncertainty quantification, feature generation, feature space analysis, and explainability. Whole-slide image processing is highly optimized, enabling whole-slide tile extraction at 40x magnification in 2.5 s per slide. The framework-agnostic data processing pipeline enables rapid experimentation with new methods built with either Tensorflow or PyTorch, and the graphical user interface supports real-time visualization of slides, predictions, heatmaps, and feature space characteristics on a variety of hardware devices, including ARM-based devices such as the Raspberry Pi.


Assuntos
Aprendizado Profundo , Software , Computadores , Processamento de Imagem Assistida por Computador/métodos
2.
Dig Dis Sci ; 69(8): 2955-2960, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38811503

RESUMO

BACKGROUND: The Endoscopic Healing Index (EHI) analyzes biomarkers in a patient's peripheral blood to assess mucosal healing. We aimed to characterize the effectiveness of the EHI as a predictor of disease activity in a real world clinical setting. METHODS: This retrospective study looked at patients treated and followed up at the University of Chicago Medicine IBD center who had EHI tests done as part of routine clinical care. The results of the EHI were compared with radiological imaging or endoscopy performed within 3 months of the EHI in order to determine accuracy at diagnosing active inflammation. RESULTS: Fifty-five patients with CD and with an available EHI were included in this study. Four (50%) patients with an EHI of < 20 (n = 8) had evidence of objective inflammation. A cutoff of ≤ 20 had a sensitivity of 89% and specificity of 23.5% for predicting no evidence of any objective inflammation with an AUROC of 0.69. This score had a negative predictive value (NPV) of 50% and positive predictive value (PPV) of 72.3%. A cutoff EHI of 30 tended to classify patients as either having objective evidence of inflammation or not more often than FCAL (Correctly classifying inflammation: 89% vs 64%, respectively; p = 0.32). CONCLUSION: In this real world analysis, the EHI showed poor predictive value for the absence of active inflammation as assessed by imaging or endoscopy, has limited utility in confirming deep remission and should be used with another objective modality.


Assuntos
Doença de Crohn , Humanos , Doença de Crohn/diagnóstico , Doença de Crohn/sangue , Masculino , Feminino , Estudos Retrospectivos , Adulto , Pessoa de Meia-Idade , Centros de Atenção Terciária , Valor Preditivo dos Testes , Índice de Gravidade de Doença , Biomarcadores/sangue , Adulto Jovem , Endoscopia Gastrointestinal , Cicatrização , Mucosa Intestinal/patologia , Mucosa Intestinal/diagnóstico por imagem
3.
Arch Dis Child Educ Pract Ed ; 108(5): 330-334, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-35790339

RESUMO

Eating disorder presentations in children and young people during the COVID-19 pandemic have increased, and this has become a common presentation to paediatric emergency departments (EDs). We cover a structured approach on identifying and managing these presentations within the ED including history taking, what to look for on examination, what investigations are needed and how to decide who requires admission to hospital.


Assuntos
COVID-19 , Transtornos da Alimentação e da Ingestão de Alimentos , Criança , Humanos , Adolescente , Pandemias , Encaminhamento e Consulta , Transtornos da Alimentação e da Ingestão de Alimentos/diagnóstico , Transtornos da Alimentação e da Ingestão de Alimentos/terapia , Serviço Hospitalar de Emergência
4.
Dis Colon Rectum ; 65(S1): S77-S84, 2022 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-35867686

RESUMO

BACKGROUND: Patients with ulcerative colitis often develop medically refractory colonic inflammation or colorectal neoplasia, and approximately 10% to 15% of patients require surgery. The most common surgical procedure is a restorative proctocolectomy with IPAA. Even if the preoperative diagnosis is ulcerative colitis, approximately 10% of patients can develop inflammatory pouch conditions resembling a Crohn's disease phenotype. OBJECTIVE: This study aimed to review the diagnostic approach, prognosis, and management of IPAA with Crohn's disease-like features. DATA SOURCES: The data sources include search in electronic databases. STUDY SELECTION: This narrative review included studies focusing on pouches with Crohn's disease-like features. MAIN OUTCOME MEASURES: The main topics in this review included the pathogenesis, risk factors, diagnosis, phenotypes, prognosis, and medications of pouches with Crohn's disease-like features. RESULTS: A diagnostic approach for the pouch conditions resembling a Crohn's disease phenotype should be based on history-taking to evaluate its risk factors and endoscopic assessment of the pouch. Prior disease history and pathology, location of pouch complications, and timing of complications offer clues for the differential diagnosis of this phenotype. We advocate for the more descriptive term "pouch with Crohn's disease-like features" and reserve the term "Crohn's disease of the pouch" for patients who undergo IPAA and have a precolectomy diagnosis of Crohn's disease or whose colectomy pathology revealed Crohn's disease. Medications, which are often used for traditional Crohn's disease, show efficacy in pouches with Crohn's disease-like features as well. The poor prognosis associated with pouches with Crohn's disease-like features, particularly the fistulizing phenotype, underscores the importance of proactive monitoring and therapeutic intervention. LIMITATIONS: The limitations include no explicit criteria for article selection. CONCLUSIONS: This review suggests future research should seek to understand the natural history and meaningful shorter and longer term therapeutic targets for these types of pouch phenotypes. Long-term follow-up and prospective preoperative and postoperative interventional trials of treatments and prevention strategies are needed.


Assuntos
Colite Ulcerativa , Bolsas Cólicas , Doença de Crohn , Proctocolectomia Restauradora , Humanos , Doença de Crohn/diagnóstico , Doença de Crohn/cirurgia , Colite Ulcerativa/cirurgia , Bolsas Cólicas/efeitos adversos , Estudos Prospectivos , Proctocolectomia Restauradora/efeitos adversos , Proctocolectomia Restauradora/métodos
5.
J Biol Chem ; 295(39): 13664-13676, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32759309

RESUMO

Staphylococcal peptidoglycan is characterized by pentaglycine cross-bridges that are cross-linked between adjacent wall peptides by penicillin-binding proteins to confer robustness and flexibility. In Staphylococcus aureus, pentaglycine cross-bridges are synthesized by three proteins: FemX adds the first glycine, and the homodimers FemA and FemB sequentially add two Gly-Gly dipeptides. Occasionally, serine residues are also incorporated into the cross-bridges by enzymes that have heretofore not been identified. Here, we show that the FemA/FemB homologues FmhA and FmhC pair with FemA and FemB to incorporate Gly-Ser dipeptides into cross-bridges and to confer resistance to lysostaphin, a secreted bacteriocin that cleaves the pentaglycine cross-bridge. FmhA incorporates serine residues at positions 3 and 5 of the cross-bridge. In contrast, FmhC incorporates a single serine at position 5. Serine incorporation also lowers resistance toward oxacillin, an antibiotic that targets penicillin-binding proteins, in both methicillin-sensitive and methicillin-resistant strains of S. aureus FmhC is encoded by a gene immediately adjacent to lytN, which specifies a hydrolase that cleaves the bond between the fifth glycine of cross-bridges and the alanine of the adjacent stem peptide. In this manner, LytN facilitates the separation of daughter cells. Cell wall damage induced upon lytN overexpression can be alleviated by overexpression of fmhC. Together, these observations suggest that FmhA and FmhC generate peptidoglycan cross-bridges with unique serine patterns that provide protection from endogenous murein hydrolases governing cell division and from bacteriocins produced by microbial competitors.


Assuntos
Proteínas de Bactérias/metabolismo , Peptidoglicano/metabolismo , Serina/metabolismo , Staphylococcus aureus/metabolismo
6.
Arch Dis Child Educ Pract Ed ; 105(2): 84-88, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-30914405

RESUMO

A 13-year-old girl presents to the emergency department for the second time with an unresponsive episode. She has a GCS (Glasgow Coma Scale) score of 11 on arrival and all other observations are normal. The story is unclear, but there are ongoing safeguarding concerns and the family are known to social services. All investigations are normal. After a period of observation on the ward, her GCS returns to normal and she appears well. Both on the first presentation and this presentation ingestion of a toxin was suspected. However, this was denied by the patient and urine toxicology screen was negative. Does this rule out toxin ingestion? Will this change your management?


Assuntos
Distúrbios Induzidos Quimicamente/diagnóstico , Urinálise , Adolescente , Distúrbios Induzidos Quimicamente/urina , Serviço Hospitalar de Emergência , Feminino , Escala de Coma de Glasgow , Humanos , Sensibilidade e Especificidade
7.
Arch Dis Child Educ Pract Ed ; 104(3): 150-153, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30026267

RESUMO

A 3-month-old baby is brought to the paediatric emergency department by their parents because of a fever. You decide to check their inflammatory markers. Their C-reactive protein (CRP) level comes back as 20 mg/L. Does this affect whether or not you start antibiotic therapy? Does it influence your decision to admit or discharge the patient? CRP is a commonly used biochemical test and yet its use is constantly debated and challenged. We look at the current evidence and suggest the best way to use this test in clinical practice.


Assuntos
Proteína C-Reativa/análise , Tomada de Decisão Clínica , Antibacterianos/uso terapêutico , Infecções Bacterianas/sangue , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/tratamento farmacológico , Biomarcadores/sangue , Proteína C-Reativa/fisiologia , Febre/etiologia , Humanos , Inflamação/diagnóstico , Pediatria
8.
Arch Dis Child Educ Pract Ed ; 103(6): 321-326, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-29332001

RESUMO

Spontaneous bleeding in the neonatal period is an unusual presentation, and yet one that can pose a challenge of both diagnosis and management to the general paediatrician. This case chronicles the diagnostic journey of an 8-day-old baby who presented with unrelenting bleeding from the umbilical cord and explores the clinical approach to bleeding in a neonate.


Assuntos
Afibrinogenemia/diagnóstico , Hemorragia/etiologia , Cordão Umbilical , Feminino , Humanos , Recém-Nascido
9.
Arch Dis Child Educ Pract Ed ; 103(2): 58-64, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-28754804

RESUMO

Monogenic forms of diabetes (historically known as Maturity Onset Diabetes of the Young (MODY)) are caused by single gene mutations inherited in an autosomal dominant fashion that result in reduced pancreatic beta cell function. Children with these forms of diabetes may be misdiagnosed as having type 1 or 2 diabetes, which has important implications for treatment, genetic counselling, screening of family members and prognosis. Useful tools now exist to aid in their diagnosis and management. Here, we attempt to outline the clinical features that will help the physician make the differentiation from other diabetes subtypes.


Assuntos
Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/terapia , Erros de Diagnóstico/prevenção & controle , Guias de Prática Clínica como Assunto , Doenças Raras/diagnóstico , Doenças Raras/terapia , Encaminhamento e Consulta , Adolescente , Criança , Pré-Escolar , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/fisiopatologia , Diagnóstico Diferencial , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Doenças Raras/genética
10.
Arch Dis Child Educ Pract Ed ; 101(2): 96-101, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26837500

RESUMO

There are over 300 new cases of imported paediatric malaria in the UK each year and this has been increasing over the last 20 years. Malaria in children is particularly difficult to diagnose because the initial presenting features are subtler than in adults and do not display the classical presenting features. However, they are also more likely to deteriorate rapidly and to develop severe malaria. The 'gold standard' for ruling out the diagnosis of malaria if clinically suspected is three negative thin and thick blood films, which require serial phlebotomy and the availability of trained technicians. There are now a range of other tests, including rapid diagnostic tests and PCR, as well as clinical features that make the diagnosis more or less likely. We explore the different tests available and whether these might replace the three negative blood films currently needed. We also look at whether we are able to use clinical features to aid the tests used for a diagnosis of imported malaria.


Assuntos
Testes Diagnósticos de Rotina/métodos , Malária/diagnóstico , Humanos , Reprodutibilidade dos Testes
11.
Arch Dis Child Educ Pract Ed ; 101(5): 246-51, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27325614

RESUMO

Mast cell tryptase (tryptase) is an enzyme produced almost exclusively by mast cells that is easy to measure using a widely available test. In this article we discuss the physiology of the mast cell and how that relates to IgE-mediated anaphylaxis and mastocytosis. We also describe the technical aspects of testing tryptase and the reported normal ranges in health. Finally we explore the diagnostic performance of serum mast cell tryptase measurements, when used to confirm anaphylaxis, estimate future anaphylaxis risk and in diagnosing/monitoring leukaemia.


Assuntos
Anafilaxia/diagnóstico , Mastócitos/fisiologia , Mastocitose/diagnóstico , Anafilaxia/etiologia , Anafilaxia/metabolismo , Humanos , Mastocitose/etiologia , Mastocitose/metabolismo , Triptases/metabolismo
12.
Cell Rep ; 43(8): 114551, 2024 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-39067022

RESUMO

Ovarian cancer is characterized by early metastatic spread. This study demonstrates that carcinoma-associated mesenchymal stromal cells (CA-MSCs) enhance metastasis by increasing tumor cell heterogeneity through mitochondrial donation. CA-MSC mitochondrial donation preferentially occurs in ovarian cancer cells with low levels of mitochondria ("mito poor"). CA-MSC mitochondrial donation rescues the phenotype of mito poor cells, restoring their proliferative capacity, resistance to chemotherapy, and cellular respiration. Receipt of CA-MSC-derived mitochondria induces tumor cell transcriptional changes leading to the secretion of ANGPTL3, which enhances the proliferation of tumor cells without CA-MSC mitochondria, thus amplifying the impact of mitochondrial transfer. Donated CA-MSC mitochondrial DNA persisted in recipient tumor cells for at least 14 days. CA-MSC mitochondrial donation occurs in vivo, enhancing tumor cell heterogeneity and decreasing mouse survival. Collectively, this work identifies CA-MSC mitochondrial transfer as a critical mediator of ovarian cancer cell survival, heterogeneity, and metastasis and presents a unique therapeutic target in ovarian cancer.


Assuntos
Células-Tronco Mesenquimais , Mitocôndrias , Metástase Neoplásica , Neoplasias Ovarianas , Feminino , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/genética , Mitocôndrias/metabolismo , Células-Tronco Mesenquimais/metabolismo , Humanos , Animais , Camundongos , Linhagem Celular Tumoral , Proliferação de Células , DNA Mitocondrial/metabolismo , DNA Mitocondrial/genética
13.
EBioMedicine ; 107: 105276, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39197222

RESUMO

BACKGROUND: Deployment and access to state-of-the-art precision medicine technologies remains a fundamental challenge in providing equitable global cancer care in low-resource settings. The expansion of digital pathology in recent years and its potential interface with diagnostic artificial intelligence algorithms provides an opportunity to democratize access to personalized medicine. Current digital pathology workstations, however, cost thousands to hundreds of thousands of dollars. As cancer incidence rises in many low- and middle-income countries, the validation and implementation of low-cost automated diagnostic tools will be crucial to helping healthcare providers manage the growing burden of cancer. METHODS: Here we describe a low-cost ($230) workstation for digital slide capture and computational analysis composed of open-source components. We analyze the predictive performance of deep learning models when they are used to evaluate pathology images captured using this open-source workstation versus images captured using common, significantly more expensive hardware. Validation studies assessed model performance on three distinct datasets and predictive models: head and neck squamous cell carcinoma (HPV positive versus HPV negative), lung cancer (adenocarcinoma versus squamous cell carcinoma), and breast cancer (invasive ductal carcinoma versus invasive lobular carcinoma). FINDINGS: When compared to traditional pathology image capture methods, low-cost digital slide capture and analysis with the open-source workstation, including the low-cost microscope device, was associated with model performance of comparable accuracy for breast, lung, and HNSCC classification. At the patient level of analysis, AUROC was 0.84 for HNSCC HPV status prediction, 1.0 for lung cancer subtype prediction, and 0.80 for breast cancer classification. INTERPRETATION: Our ability to maintain model performance despite decreased image quality and low-power computational hardware demonstrates that it is feasible to massively reduce costs associated with deploying deep learning models for digital pathology applications. Improving access to cutting-edge diagnostic tools may provide an avenue for reducing disparities in cancer care between high- and low-income regions. FUNDING: Funding for this project including personnel support was provided via grants from NIH/NCIR25-CA240134, NIH/NCIU01-CA243075, NIH/NIDCRR56-DE030958, NIH/NCIR01-CA276652, NIH/NCIK08-CA283261, NIH/NCI-SOAR25CA240134, SU2C (Stand Up to Cancer) Fanconi Anemia Research Fund - Farrah Fawcett Foundation Head and Neck Cancer Research Team Grant, and the European UnionHorizon Program (I3LUNG).


Assuntos
Aprendizado Profundo , Humanos , Processamento de Imagem Assistida por Computador/métodos , Biologia Computacional/métodos , Biologia Computacional/economia , Algoritmos , Neoplasias/patologia , Neoplasias/diagnóstico
14.
Nat Med ; 30(4): 1174-1190, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38641744

RESUMO

Despite increasing numbers of regulatory approvals, deep learning-based computational pathology systems often overlook the impact of demographic factors on performance, potentially leading to biases. This concern is all the more important as computational pathology has leveraged large public datasets that underrepresent certain demographic groups. Using publicly available data from The Cancer Genome Atlas and the EBRAINS brain tumor atlas, as well as internal patient data, we show that whole-slide image classification models display marked performance disparities across different demographic groups when used to subtype breast and lung carcinomas and to predict IDH1 mutations in gliomas. For example, when using common modeling approaches, we observed performance gaps (in area under the receiver operating characteristic curve) between white and Black patients of 3.0% for breast cancer subtyping, 10.9% for lung cancer subtyping and 16.0% for IDH1 mutation prediction in gliomas. We found that richer feature representations obtained from self-supervised vision foundation models reduce performance variations between groups. These representations provide improvements upon weaker models even when those weaker models are combined with state-of-the-art bias mitigation strategies and modeling choices. Nevertheless, self-supervised vision foundation models do not fully eliminate these discrepancies, highlighting the continuing need for bias mitigation efforts in computational pathology. Finally, we demonstrate that our results extend to other demographic factors beyond patient race. Given these findings, we encourage regulatory and policy agencies to integrate demographic-stratified evaluation into their assessment guidelines.


Assuntos
Glioma , Neoplasias Pulmonares , Humanos , Viés , Negro ou Afro-Americano , População Negra , Demografia , Erros de Diagnóstico , Glioma/diagnóstico , Glioma/genética , Brancos
15.
Res Sq ; 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38883758

RESUMO

A deep learning model using attention-based multiple instance learning (aMIL) and self-supervised learning (SSL) was developed to perform pathologic classification of neuroblastic tumors and assess MYCN-amplification status using H&E-stained whole slide digital images. The model demonstrated strong performance in identifying diagnostic category, grade, mitosis-karyorrhexis index (MKI), and MYCN-amplification on an external test dataset. This AI-based approach establishes a valuable tool for automating diagnosis and precise classification of neuroblastoma tumors.

16.
NPJ Precis Oncol ; 8(1): 114, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38783041

RESUMO

The proto-oncogene MYC encodes a nuclear transcription factor that has an important role in a variety of cellular processes, such as cell cycle progression, proliferation, metabolism, adhesion, apoptosis, and therapeutic resistance. MYC amplification is consistently observed in aggressive forms of several solid malignancies and correlates with poor prognosis and distant metastases. While the tumorigenic effects of MYC in patients with head and neck squamous cell carcinoma (HNSCC) are well known, the molecular mechanisms by which the amplification of this gene may confer treatment resistance, especially to immune checkpoint inhibitors, remains under-investigated. Here we present a unique case of a patient with recurrent/metastatic (R/M) HNSCC who, despite initial response to nivolumab-based treatment, developed rapidly progressive metastatic disease after the acquisition of MYC amplification. We conducted comparative transcriptomic analysis of this patient's tumor at baseline and upon progression to interrogate potential molecular processes through which MYC may confer resistance to immunotherapy and/or chemoradiation and used TCGA-HNSC dataset and an institutional cohort to further explore clinicopathologic features and key molecular networks associated with MYC amplification in HNSCC. This study highlights MYC amplification as a potential mechanism of immune checkpoint inhibitor resistance and suggest its use as a predictive biomarker and potential therapeutic target in R/M HNSCC.

17.
NPJ Precis Oncol ; 8(1): 130, 2024 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-38851780

RESUMO

Oral squamous cell carcinoma (OSCC) biomarker studies rarely employ multi-omic biomarker strategies and pertinent clinicopathologic characteristics to predict mortality. In this study we determine for the first time a combined epigenetic, gene expression, and histology signature that differentiates between patients with different tobacco use history (heavy tobacco use with ≥10 pack years vs. no tobacco use). Using The Cancer Genome Atlas (TCGA) cohort (n = 257) and an internal cohort (n = 40), we identify 3 epigenetic markers (GPR15, GNG12, GDNF) and 13 expression markers (IGHA2, SCG5, RPL3L, NTRK1, CD96, BMP6, TFPI2, EFEMP2, RYR3, DMTN, GPD2, BAALC, and FMO3), which are dysregulated in OSCC patients who were never smokers vs. those who have a ≥ 10 pack year history. While mortality risk prediction based on smoking status and clinicopathologic covariates alone is inaccurate (c-statistic = 0.57), the combined epigenetic/expression and histologic signature has a c-statistic = 0.9409 in predicting 5-year mortality in OSCC patients.

19.
NPJ Digit Med ; 6(1): 75, 2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-37100871

RESUMO

Large language models such as ChatGPT can produce increasingly realistic text, with unknown information on the accuracy and integrity of using these models in scientific writing. We gathered fifth research abstracts from five high-impact factor medical journals and asked ChatGPT to generate research abstracts based on their titles and journals. Most generated abstracts were detected using an AI output detector, 'GPT-2 Output Detector', with % 'fake' scores (higher meaning more likely to be generated) of median [interquartile range] of 99.98% 'fake' [12.73%, 99.98%] compared with median 0.02% [IQR 0.02%, 0.09%] for the original abstracts. The AUROC of the AI output detector was 0.94. Generated abstracts scored lower than original abstracts when run through a plagiarism detector website and iThenticate (higher scores meaning more matching text found). When given a mixture of original and general abstracts, blinded human reviewers correctly identified 68% of generated abstracts as being generated by ChatGPT, but incorrectly identified 14% of original abstracts as being generated. Reviewers indicated that it was surprisingly difficult to differentiate between the two, though abstracts they suspected were generated were vaguer and more formulaic. ChatGPT writes believable scientific abstracts, though with completely generated data. Depending on publisher-specific guidelines, AI output detectors may serve as an editorial tool to help maintain scientific standards. The boundaries of ethical and acceptable use of large language models to help scientific writing are still being discussed, and different journals and conferences are adopting varying policies.

20.
J Biol Chem ; 286(31): 27582-93, 2011 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-21622575

RESUMO

We generated a transgenic mouse model expressing the apical hypertrophic cardiomyopathy-causing mutation ACTC E99K at 50% of total heart actin and compared it with actin from patients carrying the same mutation. The actin mutation caused a higher Ca(2+) sensitivity in reconstituted thin filaments measured by in vitro motility assay (2.3-fold for mice and 1.3-fold for humans) and in skinned papillary muscle. The mutation also abolished the change in Ca(2+) sensitivity normally linked to troponin I phosphorylation. MyBP-C and troponin I phosphorylation levels were the same as controls in transgenic mice and human carrier heart samples. ACTC E99K mice exhibited a high death rate between 28 and 45 days (48% females and 22% males). At 21 weeks, the hearts of the male survivors had enlarged atria, increased interstitial fibrosis, and sarcomere disarray. MRI showed hypertrophy, predominantly at the apex of the heart. End-diastolic volume and end-diastolic pressure were increased, and relaxation rates were reduced compared with nontransgenic littermates. End-systolic pressures and volumes were unaltered. ECG abnormalities were present, and the contractile response to ß-adrenergic stimulation was much reduced. Older mice (29-week-old females and 38-week-old males) developed dilated cardiomyopathy with increased end-systolic volume and continuing increased end-diastolic pressure and slower contraction and relaxation rates. ECG showed atrial flutter and frequent atrial ectopic beats at rest in some ACTC E99K mice. We propose that the ACTC E99K mutation causes higher myofibrillar Ca(2+) sensitivity that is responsible for the sudden cardiac death, apical hypertrophy, and subsequent development of heart failure in humans and mice.


Assuntos
Actinas/genética , Cardiomegalia/genética , Mutação , Animais , Feminino , Humanos , Masculino , Camundongos , Camundongos Transgênicos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA