Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 82
Filtrar
1.
Laryngorhinootologie ; 2024 Jun 03.
Artigo em Alemão | MEDLINE | ID: mdl-38830381

RESUMO

OBJECTIVE: Upper airway obstructions are usually acute emergencies. Coniotomy is the last option to secure the airway and can be supported by sonography. The aim of this study was to establish a training program to teach these skills. MATERIAL AND METHODS: The training consisted of theoretical training with an additional video presentation (10 minutes each) and practical training (45 minutes). Evaluations were completed before (T1) and after (T2) the training to measure prior experience and satisfaction with the training as well as subjective and objective competence levels. At T2, a practical test was also completed by n=113 participants. A standardized evaluation form was used to document the results of the practical test. RESULTS: A large proportion of the participants had neither seen a coniotomy (64.6%) nor performed one independently (79.6%). Significant improvement (T1 to T2) was measured with regard to the subjective assessment of competence (p<0.001). The training received positive ratings for all items tested (scale ranges 1-2). During practical tests, the participants achieved an average of 89.2% of the possible points and needed a mean of 101 ±23 seconds to identify the conic ligament. CONCLUSION: Structured training for sonographic identification of the conic ligament leads to significant improvement in the subjective assessment of competence and a high objective competence level in a short period of time. This type of training should be standardized in head and neck ultrasound training in the future.

2.
J Imaging Inform Med ; 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38926263

RESUMO

Standardized reporting of multiparametric prostate MRI (mpMRI) is widespread and follows international standards (Pi-RADS). However, quantitative measurements from mpMRI are not widely comparable. Although T2 mapping sequences can provide repeatable quantitative image measurements and extract reliable imaging biomarkers from mpMRI, they are often time-consuming. We therefore investigated the value of quantitative measurements on a highly accelerated T2 mapping sequence, in order to establish a threshold to differentiate benign from malignant lesions. For this purpose, we evaluated a novel, highly accelerated T2 mapping research sequence that enables high-resolution image acquisition with short acquisition times in everyday clinical practice. In this retrospective single-center study, we included 54 patients with clinically indicated MRI of the prostate and biopsy-confirmed carcinoma (n = 37) or exclusion of carcinoma (n = 17). All patients had received a standard of care biopsy of the prostate, results of which were used to confirm or exclude presence of malignant lesions. We used the linear mixed-effects model-fit by REML to determine the difference between mean values of cancerous tissue and healthy tissue. We found good differentiation between malignant lesions and normal appearing tissue in the peripheral zone based on the mean T2 value. Specifically, the mean T2 value for tissue without malignant lesions was (151.7 ms [95% CI: 146.9-156.5 ms] compared to 80.9 ms for malignant lesions [95% CI: 67.9-79.1 ms]; p < 0.001). Based on this assessment, a limit of 109.2 ms is suggested. Aditionally, a significant correlation was observed between T2 values of the peripheral zone and PI-RADS scores (p = 0.0194). However, no correlation was found between the Gleason Score and the T2 relaxation time. Using REML, we found a difference of -82.7 ms in mean values between cancerous tissue and healthy tissue. We established a cut-off-value of 109.2 ms to accurately differentiate between malignant and non-malignant prostate regions. The addition of T2 mapping sequences to routine imaging could benefit automated lesion detection and facilitate contrast-free multiparametric MRI of the prostate.

3.
bioRxiv ; 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38712110

RESUMO

Terpenoids are the largest class of natural products, found across all domains of life. One of the most abundant bacterial terpenoids is the volatile odorant 2-methylisoborneol (2-MIB), partially responsible for the earthy smell of soil and musty taste of contaminated water. Many bacterial 2-MIB biosynthetic gene clusters were thought to encode a conserved transcription factor, named EshA in the model soil bacterium Streptomyces griseus. Here, we revise the function of EshA, now referred to as Sg Enc, and show that it is a Family 2B encapsulin shell protein. Using cryo-electron microscopy, we find that Sg Enc forms an icosahedral protein shell and encapsulates 2-methylisoborneol synthase (2-MIBS) as a cargo protein. Sg Enc contains a cyclic adenosine monophosphate (cAMP) binding domain (CBD)-fold insertion and a unique metal-binding domain, both displayed on the shell exterior. We show that Sg Enc CBDs do not bind cAMP. We find that 2-MIBS cargo loading is mediated by an N-terminal disordered cargo-loading domain and that 2-MIBS activity and Sg Enc shell structure are not modulated by cAMP. Our work redefines the function of EshA and establishes Family 2B encapsulins as cargo-loaded protein nanocompartments involved in secondary metabolite biosynthesis.

4.
Ultrasound Int Open ; 10: a22710098, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38812890

RESUMO

Purpose Arthroscopy is one of the most common interventions in orthopedics. Hence it is important to train users early in order to ensure the safest possible identification of access portals (AP). This prospective study aimed to compare a palpatory (PalpMethod) with a sonographic (SonoMethod) method for AP location in the shoulder and knee joints. Materials and Methods The study included trainee doctors (n=68) attending workshops (lasting approx. 90 minutes). In these workshops a teaching video initially demonstrated the PalpMethod and SonoMethod of AP identification. An experienced operator first marked the access portals on the test subject with a UV pen (determined ideal point [DIP]). Adhesive film was then affixed to the puncture regions. Subsequently participants marked on shoulders and knees first the point determined by palpation, then the point determined by sonography. Analysis involved DIP visualization with a UV lamp and employed a coordinate system around the central DIP. In addition, participants completed an evaluation before and after the workshop. Results The analysis included 324 measurements (n=163 shoulders and n= 161 knees). The majority of participants had not previously attended any courses on manual examination (87.9%) or musculoskeletal ultrasound (93.9%). Overall, the markings participants made on the shoulder using the SonoMethod were significantly closer to the DIP than those made by the PalpMethod (Palp 18.8mm ± 14.5mm vs. Sono 11.2mm ± 7.2mm; p<0.001). On the knee, however, the markings made by the PalpMethod were significantly closer to the DIP overall (Palp 8.0mm ± 3.2mm vs. Sono 12.8mm ± 5.2mm; p<0.001). Conclusion The results show that the SonoMethod produces more accurate markings on the shoulder, while the PalpMethod is superior for the knee.

5.
bioRxiv ; 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38712103

RESUMO

Protein shells or capsids are a widespread form of compartmentalization in nature. Viruses use protein capsids to protect and transport their genomes while many cellular organisms use protein shells for varied metabolic purposes. These protein-based compartments often exhibit icosahedral symmetry and consist of a small number of structural components with defined roles. Encapsulins are a prevalent protein-based compartmentalization strategy in prokaryotes. All encapsulins studied thus far consist of a single shell protein that adopts the viral HK97-fold. Here, we report the characterization of a Family 2B two-component encapsulin from Streptomyces lydicus. We show the differential assembly behavior of the two shell components and demonstrate their ability to co-assemble into mixed shells with variable shell composition. We determined the structures of both shell proteins using cryo-electron microscopy. Using 3D-classification and crosslinking studies, we highlight the irregular tiling of mixed shells. Our work expands the known assembly modes of HK97-fold proteins and lays the foundation for future functional and engineering studies on two-component encapsulins.

6.
Proc Natl Acad Sci U S A ; 121(20): e2321260121, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38722807

RESUMO

Protein capsids are a widespread form of compartmentalization in nature. Icosahedral symmetry is ubiquitous in capsids derived from spherical viruses, as this geometry maximizes the internal volume that can be enclosed within. Despite the strong preference for icosahedral symmetry, we show that simple point mutations in a virus-like capsid can drive the assembly of unique symmetry-reduced structures. Starting with the encapsulin from Myxococcus xanthus, a 180-mer bacterial capsid that adopts the well-studied viral HK97 fold, we use mass photometry and native charge detection mass spectrometry to identify a triple histidine point mutant that forms smaller dimorphic assemblies. Using cryoelectron microscopy, we determine the structures of a precedented 60-mer icosahedral assembly and an unexpected 36-mer tetrahedron that features significant geometric rearrangements around a new interaction surface between capsid protomers. We subsequently find that the tetrahedral assembly can be generated by triple-point mutation to various amino acids and that even a single histidine point mutation is sufficient to form tetrahedra. These findings represent a unique example of tetrahedral geometry when surveying all characterized encapsulins, HK97-like capsids, or indeed any virus-derived capsids reported in the Protein Data Bank, revealing the surprising plasticity of capsid self-assembly that can be accessed through minimal changes in the protein sequence.


Assuntos
Proteínas do Capsídeo , Capsídeo , Microscopia Crioeletrônica , Mutação Puntual , Capsídeo/metabolismo , Capsídeo/química , Capsídeo/ultraestrutura , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/química , Proteínas do Capsídeo/metabolismo , Myxococcus xanthus/genética , Myxococcus xanthus/metabolismo , Modelos Moleculares
7.
bioRxiv ; 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38746127

RESUMO

Enzyme nanoreactors are nanoscale compartments consisting of encapsulated enzymes and a selectively permeable barrier. Sequestration and co-localization of enzymes can increase catalytic activity, stability, and longevity, highly desirable features for many biotechnological and biomedical applications of enzyme catalysts. One promising strategy to construct enzyme nanoreactors is to repurpose protein nanocages found in nature. However, protein-based enzyme nanoreactors often exhibit decreased catalytic activity, partially caused by a mismatch of protein shell selectivity and the substrate requirements of encapsulated enzymes. No broadly applicable and modular protein-based nanoreactor platform is currently available. Here, we introduce a pore-engineered universal enzyme nanoreactor platform based on encapsulins - microbial self-assembling protein nanocompartments with programmable and selective enzyme packaging capabilities. We structurally characterize our protein shell designs via cryo-electron microscopy and highlight their polymorphic nature. Through fluorescence polarization assays, we show their improved molecular flux behavior and highlight their expanded substrate range via a number of proof-of-concept enzyme nanoreactor designs. This work lays the foundation for utilizing our encapsulin-based nanoreactor platform for future biotechnological and biomedical applications.

8.
Nat Commun ; 15(1): 3574, 2024 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-38678027

RESUMO

Modified cyclic dipeptides represent a widespread class of secondary metabolites with diverse pharmacological activities, including antibacterial, antifungal, and antitumor. Here, we report the structural characterization of the Streptomyces noursei enzyme AlbAB, a cyclodipeptide oxidase (CDO) carrying out α,ß-dehydrogenations during the biosynthesis of the antibiotic albonoursin. We show that AlbAB is a megadalton heterooligomeric enzyme filament containing covalently bound flavin mononucleotide cofactors. We highlight that AlbAB filaments consist of alternating dimers of AlbA and AlbB and that enzyme activity is crucially dependent on filament formation. We show that AlbA-AlbB interactions are highly conserved suggesting that other CDO-like enzymes are likely enzyme filaments. As CDOs have been employed in the structural diversification of cyclic dipeptides, our results will be useful for future applications of CDOs in biocatalysis and chemoenzymatic synthesis.


Assuntos
Streptomyces , Streptomyces/enzimologia , Streptomyces/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Dipeptídeos/química , Dipeptídeos/metabolismo , Oxirredutases/metabolismo , Oxirredutases/química , Mononucleotídeo de Flavina/metabolismo , Mononucleotídeo de Flavina/química , Peptídeos Cíclicos/química , Peptídeos Cíclicos/metabolismo , Cristalografia por Raios X , Modelos Moleculares , Antibacterianos/química , Antibacterianos/farmacologia , Antibacterianos/metabolismo , Antibacterianos/biossíntese
9.
Cancer Med ; 13(5): e6981, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38477510

RESUMO

BACKGROUND: The incidence of hepatocellular carcinoma (HCC) is increasing in the western world over the past decades. As liver resection (LR) represents one of the most efficient treatment options, advantages of anatomic (ALR) versus non-anatomic liver resection (NALR) show a lack of consistent evidence. Therefore, the aim of this study was to investigate complications and survival rates after both resection types. METHODS: This is a multicentre cohort study using retrospectively and prospectively collected data. We included all patients undergoing LR for HCC between 2009 and 2020 from three specialised centres in Switzerland and Germany. Complication and survival rates after ALR versus NALR were analysed using uni- and multivariate Cox regression models. RESULTS: Two hundred and ninety-eight patients were included. Median follow-up time was 52.76 months. 164/298 patients (55%) underwent ALR. Significantly more patients with cirrhosis received NALR (n = 94/134; p < 0.001). Complications according to the Clavien Dindo classification were significantly more frequent in the NALR group (p < 0.001). Liver failure occurred in 13% after ALR versus 8% after NALR (p < 0.215). Uni- and multivariate cox regression models showed no significant differences between the groups for recurrence free survival (RFS) and overall survival (OS). Furthermore, cirrhosis had no significant impact on OS and RFS. CONCLUSION: No significant differences on RFS and OS rates could be observed. Post-operative complications were significantly less frequent in the ALR group while liver specific complications were comparable between both groups. Subgroup analysis showed no significant influence of cirrhosis on the post-operative outcome of these patients.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Estudos Retrospectivos , Estudos de Coortes , Cirrose Hepática/patologia , Hepatectomia/efeitos adversos , Resultado do Tratamento
10.
Nat Commun ; 15(1): 2558, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38519509

RESUMO

Encapsulins are self-assembling protein nanocompartments capable of selectively encapsulating dedicated cargo proteins, including enzymes involved in iron storage, sulfur metabolism, and stress resistance. They represent a unique compartmentalization strategy used by many pathogens to facilitate specialized metabolic capabilities. Encapsulation is mediated by specific cargo protein motifs known as targeting peptides (TPs), though the structural basis for encapsulation of the largest encapsulin cargo class, dye-decolorizing peroxidases (DyPs), is currently unknown. Here, we characterize a DyP-containing encapsulin from the enterobacterial pathogen Klebsiella pneumoniae. By combining cryo-electron microscopy with TP and TP-binding site mutagenesis, we elucidate the molecular basis for cargo encapsulation. TP binding is mediated by cooperative hydrophobic and ionic interactions as well as shape complementarity. Our results expand the molecular understanding of enzyme encapsulation inside protein nanocompartments and lay the foundation for rationally modulating encapsulin cargo loading for biomedical and biotechnological applications.


Assuntos
Proteínas de Bactérias , Peroxidase , Proteínas de Bactérias/metabolismo , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Microscopia Crioeletrônica , Peroxidases/metabolismo
11.
Sci Adv ; 10(5): eadk9345, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38306423

RESUMO

Subcellular compartments often serve to store nutrients or sequester labile or toxic compounds. As bacteria mostly do not possess membrane-bound organelles, they often have to rely on protein-based compartments. Encapsulins are one of the most prevalent protein-based compartmentalization strategies found in prokaryotes. Here, we show that desulfurase encapsulins can sequester and store large amounts of crystalline elemental sulfur. We determine the 1.78-angstrom cryo-EM structure of a 24-nanometer desulfurase-loaded encapsulin. Elemental sulfur crystals can be formed inside the encapsulin shell in a desulfurase-dependent manner with l-cysteine as the sulfur donor. Sulfur accumulation can be influenced by the concentration and type of sulfur source in growth medium. The selectively permeable protein shell allows the storage of redox-labile elemental sulfur by excluding cellular reducing agents, while encapsulation substantially improves desulfurase activity and stability. These findings represent an example of a protein compartment able to accumulate and store elemental sulfur.


Assuntos
Bactérias , Proteínas de Bactérias , Proteínas de Bactérias/metabolismo , Bactérias/metabolismo , Células Procarióticas/metabolismo , Oxirredução , Enxofre/metabolismo
12.
bioRxiv ; 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38370832

RESUMO

Protein capsids are a widespread form of compartmentalisation in nature. Icosahedral symmetry is ubiquitous in capsids derived from spherical viruses, as this geometry maximises the internal volume that can be enclosed within. Despite the strong preference for icosahedral symmetry, we show that simple point mutations in a virus-like capsid can drive the assembly of novel symmetry-reduced structures. Starting with the encapsulin from Myxococcus xanthus, a 180-mer bacterial capsid that adopts the well-studied viral HK97 fold, we use mass photometry and native charge detection mass spectrometry to identify a triple histidine point mutant that forms smaller dimorphic assemblies. Using cryo-EM, we determine the structures of a precedented 60-mer icosahedral assembly and an unprecedented 36-mer tetrahedron that features significant geometric rearrangements around a novel interaction surface between capsid protomers. We subsequently find that the tetrahedral assembly can be generated by triple point mutation to various amino acids, and that even a single histidine point mutation is sufficient to form tetrahedra. These findings represent the first example of tetrahedral geometry across all characterised encapsulins, HK97-like capsids, or indeed any virus-derived capsids reported in the Protein Data Bank, revealing the surprising plasticity of capsid self-assembly that can be accessed through minimal changes in protein sequence.

14.
Invest Radiol ; 59(6): 472-478, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38117123

RESUMO

BACKGROUND: Post-COVID syndrome (PCS) can adversely affect the quality of life of patients and their families. In particular, the degree of cardiac impairment in children with PCS is unknown. OBJECTIVE: The aim of this study was to identify potential cardiac inflammatory sequelae in children with PCS compared with healthy controls. METHODS: This single-center, prospective, intraindividual, observational study assesses cardiac function, global and segment-based strains, and tissue characterization in 29 age- and sex-matched children with PCS and healthy children using a 3 T magnetic resonance imaging (MRI). RESULTS: Cardiac MRI was carried out over 36.4 ± 24.9 weeks post-COVID infection. The study cohort has an average age of 14.0 ± 2.8 years, for which the majority of individuals experience from fatigue, concentration disorders, dyspnea, dizziness, and muscle ache. Children with PSC in contrast to the control group exhibited elevated heart rate (83.7 ± 18.1 beats per minute vs 75.2 ± 11.2 beats per minute, P = 0.019), increased indexed right ventricular end-diastolic volume (95.2 ± 19.2 mlm -2 vs 82.0 ± 21.5 mlm -2 , P = 0.018) and end-systolic volume (40.3 ± 7.9 mlm -2 vs 34.8 ± 6.2 mlm -2 , P = 0.005), and elevated basal and midventricular T1 and T2 relaxation times ( P < 0.001 to P = 0.013). Based on the updated Lake Louise Criteria, myocardial inflammation is present in 20 (69%) children with PCS. No statistically significant difference was observed for global strains. CONCLUSIONS: Cardiac MRI revealed altered right ventricular volumetrics and elevated T1 and T2 mapping values in children with PCS, suggestive for a diffuse myocardial inflammation, which may be useful for the diagnostic workup of PCS in children.


Assuntos
COVID-19 , Imageamento por Ressonância Magnética , Humanos , Masculino , Feminino , COVID-19/diagnóstico por imagem , COVID-19/complicações , Adolescente , Estudos Prospectivos , Criança , Imageamento por Ressonância Magnética/métodos , SARS-CoV-2 , Estudos de Casos e Controles , Síndrome de COVID-19 Pós-Aguda , Coração/diagnóstico por imagem
15.
Acad Radiol ; 31(5): 1784-1791, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38155024

RESUMO

RATIONALE AND OBJECTIVES: The prognostic role of pericardial effusion (PE) in Covid 19 is unclear. The aim of the present study was to estimate the prognostic role of PE in patients with Covid 19 in a large multicentre setting. MATERIALS AND METHODS: This retrospective study is a part of the German multicenter project RACOON (Radiological Cooperative Network of the Covid 19 pandemic). The acquired sample comprises 1197 patients, 363 (30.3%) women and 834 (69.7%) men. In every case, chest computed tomography was analyzed for PE. Data about 30-day mortality, need for mechanical ventilation and need for intensive care unit (ICU) admission were collected. Data were evaluated by means of descriptive statistics. Group differences were calculated with Mann-Whitney test and Fisher exact test. Uni-and multivariable regression analyses were performed. RESULTS: Overall, 46.4% of the patients were admitted to ICU, mechanical lung ventilation was performed in 26.6% and 30-day mortality was 24%. PE was identified in 159 patients (13.3%). The presence of PE was associated with 30-day mortality: HR= 1.54, CI 95% (1.05; 2.23), p = 0.02 (univariable analysis), and HR= 1.60, CI 95% (1.03; 2.48), p = 0.03 (multivariable analysis). Furthermore, density of PE was associated with the need for intubation (OR=1.02, CI 95% (1.003; 1.05), p = 0.03) and the need for ICU admission (OR=1.03, CI 95% (1.005; 1.05), p = 0.01) in univariable regression analysis. The presence of PE was associated with 30-day mortality in male patients, HR= 1.56, CI 95%(1.01-2.43), p = 0.04 (multivariable analysis). In female patients, none of PE values predicted clinical outcomes. CONCLUSION: The prevalence of PE in Covid 19 is 13.3%. PE is an independent predictor of 30-day mortality in male patients with Covid 19. In female patients, PE plays no predictive role.


Assuntos
COVID-19 , Derrame Pericárdico , Tomografia Computadorizada por Raios X , Humanos , Masculino , Feminino , COVID-19/mortalidade , COVID-19/epidemiologia , COVID-19/diagnóstico por imagem , COVID-19/complicações , Estudos Retrospectivos , Derrame Pericárdico/diagnóstico por imagem , Derrame Pericárdico/epidemiologia , Idoso , Pessoa de Meia-Idade , Prognóstico , Alemanha/epidemiologia , Respiração Artificial/estatística & dados numéricos , SARS-CoV-2 , Unidades de Terapia Intensiva , Idoso de 80 Anos ou mais
16.
bioRxiv ; 2023 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-37790520

RESUMO

Encapsulins are self-assembling protein nanocompartments capable of selectively encapsulating dedicated cargo proteins, including enzymes involved in iron storage, sulfur metabolism, and stress resistance. They represent a unique compartmentalization strategy used by many pathogens to facilitate specialized metabolic capabilities. Encapsulation is mediated by specific cargo protein motifs known as targeting peptides (TPs), though the structural basis for encapsulation of the largest encapsulin cargo class, dye-decolorizing peroxidases (DyPs), is currently unknown. Here, we characterize a DyP-containing encapsulin from the enterobacterial pathogen Klebsiella pneumoniae. By combining cryo-electron microscopy with TP mutagenesis, we elucidate the molecular basis for cargo encapsulation. TP binding is mediated by cooperative hydrophobic and ionic interactions as well as shape complementarity. Our results expand the molecular understanding of enzyme encapsulation inside protein nanocompartments and lay the foundation for rationally modulating encapsulin cargo loading for biomedical and biotechnological applications.

17.
Diagnostics (Basel) ; 13(20)2023 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-37892093

RESUMO

BACKGROUND: ultrasound diagnostics have a broad spectrum of applications, including among diseases of the musculoskeletal system. Accordingly, it is important for the users to have a well-founded and up-to-date education in this dynamic examination method. The right balance between online and in-class teaching still needs to be explored in this context. Certifying institutions are currently testing digitally transformed teaching concepts to provide more evidence. METHODS: this study compared two musculoskeletal ultrasound blended learning models. Model A was more traditional, with a focus on in-person teaching, while Model B was more digitally oriented with compulsory webinar. Both used e-learning for preparation. Participants completed evaluations using a seven-point Likert scale, later converted to a 0-1 scale. Digital teaching media (e-learning) were used for preparation in both courses. RESULTS: the analysis included n = 41 evaluations for Model A and n = 30 for Model B. Model B received a better overall assessment (median: 0.73 vs. 0.69, p = 0.05). Model B also excelled in "course preparation" (p = 0.02), "webinar quality" (p = 0.04), and "course concept" (p = 0.04). The "gain of competence" (p = 0.82), "learning materials" (p = 0.30), and "tutor quality" (p = 0.28) showed no significant differences. CONCLUSION: participants favorably assessed blended learning in ultrasound teaching. Certifying institutions should consider accrediting models that combine digital methods (e.g., internet lectures/webinars) and materials (e.g., e-learning) with hands-on ultrasound training. Further research is needed to validate these subjective findings for a stronger evidential basis.

18.
bioRxiv ; 2023 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-37808672

RESUMO

Modified cyclic dipeptides represent a widespread class of secondary metabolites with diverse pharmacological activities, including antibacterial, antifungal, and antitumor. Here, we report the structural characterization of the Streptomyces noursei enzyme AlbAB, a cyclodipeptide oxidase (CDO) carrying out α,ß-dehydrogenations during the biosynthesis of the antibiotic albonoursin. We show that AlbAB is a megadalton heterooligomeric enzyme filament containing covalently bound flavin mononucleotide cofactors. We highlight that AlbAB filaments consist of alternating dimers of AlbA and AlbB and that enzyme activity is crucially dependent on filament formation. We show that AlbA-AlbB interactions are highly conserved suggesting that all CDO-like enzymes are likely enzyme filaments. Our work represents the first structural characterization of a CDO. As CDOs have been employed in the structural diversification of cyclic dipeptides, our results will be useful for future applications of CDOs in biocatalysis and chemoenzymatic synthesis.

19.
J Struct Biol ; 215(4): 108022, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37657675

RESUMO

Encapsulins are self-assembling protein nanocompartments able to selectively encapsulate dedicated cargo enzymes. Encapsulins are widespread across bacterial and archaeal phyla and are involved in oxidative stress resistance, iron storage, and sulfur metabolism. Encapsulin shells exhibit icosahedral geometry and consist of 60, 180, or 240 identical protein subunits. Cargo encapsulation is mediated by the specific interaction of targeting peptides or domains, found in all cargo proteins, with the interior surface of the encapsulin shell during shell self-assembly. Here, we report the 2.53 Å cryo-EM structure of a heterologously produced and highly cargo-loaded T3 encapsulin shell from Myxococcus xanthus and explore the systems' structural heterogeneity. We find that exceedingly high cargo loading results in the formation of substantial amounts of distorted and aberrant shells, likely caused by a combination of unfavorable steric clashes of cargo proteins and shell conformational changes. Based on our cryo-EM structure, we determine and analyze the targeting peptide-shell binding mode. We find that both ionic and hydrophobic interactions mediate targeting peptide binding. Our results will guide future attempts at rationally engineering encapsulins for biomedical and biotechnological applications.


Assuntos
Bactérias , Proteínas de Bactérias , Proteínas de Bactérias/química , Bactérias/metabolismo , Estresse Oxidativo , Archaea/metabolismo , Peptídeos/metabolismo
20.
Healthcare (Basel) ; 11(17)2023 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-37685411

RESUMO

Data-driven machine learning in medical research and diagnostics needs large-scale datasets curated by clinical experts. The generation of large datasets can be challenging in terms of resource consumption and time effort, while generalizability and validation of the developed models significantly benefit from variety in data sources. Training algorithms on smaller decentralized datasets through federated learning can reduce effort, but require the implementation of a specific and ambitious infrastructure to share data, algorithms and computing time. Additionally, it offers the opportunity of maintaining and keeping the data locally. Thus, data safety issues can be avoided because patient data must not be shared. Machine learning models are trained on local data by sharing the model and through an established network. In addition to commercial applications, there are also numerous academic and customized implementations of network infrastructures available. The configuration of these networks primarily differs, yet adheres to a standard framework composed of fundamental components. In this technical note, we propose basic infrastructure requirements for data governance, data science workflows, and local node set-up, and report on the advantages and experienced pitfalls in implementing the local infrastructure with the German Radiological Cooperative Network initiative as the use case example. We show how the infrastructure can be built upon some base components to reflect the needs of a federated learning network and how they can be implemented considering both local and global network requirements. After analyzing the deployment process in different settings and scenarios, we recommend integrating the local node into an existing clinical IT infrastructure. This approach offers benefits in terms of maintenance and deployment effort compared to external integration in a separate environment (e.g., the radiology department). This proposed groundwork can be taken as an exemplary development guideline for future applications of federated learning networks in clinical and scientific environments.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...