660 research outputs found
Zebrafish as a model for cardiac disease; Cryo-EM structure of native cardiac thin filaments from Danio Rerio.
Actin, tropomyosin and troponin, the proteins that comprise the contractile apparatus of the cardiac thin filament, are highly conserved across species. We have used cryo-EM to study the three-dimensional structure of the zebrafish cardiac thin and actin filaments. With 70% of human genes having an obvious zebrafish orthologue, and conservation of 85% of disease-causing genes, zebrafish are a good animal model for the study of human disease. Our structure of the zebrafish thin filament reveals the molecular interactions between the constituent proteins, showing that the fundamental organisation of the complex is the same as that reported in the human reconstituted thin filament. A reconstruction of zebrafish cardiac F-actin demonstrates no deviations from human cardiac actin over an extended length of 14 actin subunits. Modelling zebrafish homology models into our maps enabled us to compare, in detail, the similarity with human models. The structural similarities of troponin-T in particular, a region known to contain a hypertrophic cardiomyopathy 'hotspot', confirm the suitability of zebrafish to study these disease-causing mutations
Advances in pre-treatment evaluation of pancreatic ductal adenocarcinoma: a narrative review
Background and Objective: Despite advances in the multidisciplinary management of pancreatic cancer, overall prognosis remains poor, due to early progression of the disease. There is a need to also take action in staging, to make it increasingly accurate and complete, to define the setting of the therapeutic strategy. This review was planned to update the current status of pre-treatment evaluation for pancreatic cancer. Methods: We conducted an extensive review, including relevant articles dealing with traditional imaging, functional imaging and minimally invasive surgical procedures before treatment for pancreatic cancer. We searched articles written in English only. Data in the PubMed database, published in the period between January 2000 and January 2022, were retrieved. Prospective observational studies, retrospective analyses and meta-analyses were reviewed and analysed. Key Content and Findings: Each imaging modality (endoscopic ultrasonography, endoscopic retrograde staging laparoscopy) has its own diagnostic advantages and limitations. The sensitivity, specificity and accuracy for each image set are reported. Data that support the increasing role of neoadjuvant therapy (radiotherapy and chemotherapy) and the meaning of a patient-tailored treatment selection, based on tumour staging, are also discussed. Conclusions: A multimodal pre-treatment workup should be searched as it improves staging accuracy, orienting patients with resectable tumors towards surgery, optimizing patient selection with locally advanced tumors to neoadjuvant or definite therapy and avoiding surgical resection or curative radiotherapy in those with metastatic disease
Time-Fractional Optimal Control of Initial Value Problems on Time Scales
We investigate Optimal Control Problems (OCP) for fractional systems
involving fractional-time derivatives on time scales. The fractional-time
derivatives and integrals are considered, on time scales, in the
Riemann--Liouville sense. By using the Banach fixed point theorem, sufficient
conditions for existence and uniqueness of solution to initial value problems
described by fractional order differential equations on time scales are known.
Here we consider a fractional OCP with a performance index given as a
delta-integral function of both state and control variables, with time evolving
on an arbitrarily given time scale. Interpreting the Euler--Lagrange first
order optimality condition with an adjoint problem, defined by means of right
Riemann--Liouville fractional delta derivatives, we obtain an optimality system
for the considered fractional OCP. For that, we first prove new fractional
integration by parts formulas on time scales.Comment: This is a preprint of a paper accepted for publication as a book
chapter with Springer International Publishing AG. Submitted 23/Jan/2019;
revised 27-March-2019; accepted 12-April-2019. arXiv admin note: substantial
text overlap with arXiv:1508.0075
Impact of Age on Outcomes of Patients With Pure Carcinoma In Situ of the Bladder: Multi-Institutional Cohort Analysis
Introduction: The aim of this multicenter study was to investigate the role of age (cut-off 70 years) at diagnosis in predicting oncologic behavior of pure carcinoma in situ of the bladder.
Material and methods: Inclusion criteria were: patients with pure CIS confirmed and that followed intravesical BCG treatment. Pure CIS was defined at any CIS not associated with another urothelial cancer. Exclusion criteria were: any CIS associated with invasive urothelial carcinoma. A total of 172 with pure CIS treated between January 1, 2002 and December 31, 2012 at 8 academic institutions met the inclusion criteria. The maintenance schedule was generally according to the EAU guidelines at the time RESULTS: A total of 99 (57.6%) patients had an age >70 years prior to TURBT. There was no difference between clinico-pathologic features among groups (group 1, age ≤ 70 years and group 2, age > 70 years), except that patients aged ≤ 70 years presented a larger size of CIS (35.6% vs. 21.2%), P = .02. In multivariable Cox regression analyses, the same clinico-pathologic factors (age, multifocality, and recurrent tumor state) were independently associated with worse RFS. Harrell's C-index was 65.75.In multivariable Cox regression analyses in addition to age (P = .006) and multifocality (P < .001) also BMI (P = .04) was independently associated with worse PFS. Harrell's C-index was 74.71 CONCLUSION: Advanced age at diagnosis appears to be associated with an increased risk of recurrence and progression of pure carcinoma in situ of the bladder. Elderly patients might fail to respond to BCG therapy
Association between intra-radicular posts and periapical lesions in endodontically treated teeth
Introduction: A significant number of endodontically treated teeth restored with posts have associated periapical lesions, and several authors have discussed the probable causes of the development of these. Attention has been focused on restorative procedures performed after endodontic treatment and their association with the prognosis of endodontic therapy because a number of root-filled teeth will require post- and core-retained restorations. Purpose: The purpose of this study was to evaluate, by examination of periapical radiographs, whether the placement of intra-radicular posts in endodontically treated teeth may act as a risk factor for development of periapical lesions. Material and Methods: This case-control study analyzed periapical radiographs of 72 endodontically treated teeth with coronal restorations. All radiographs were obtained from a single private practice. Specimens were assigned to 2 groups: Group 1 (control) was composed of teeth without periapical lesions and Group 2 (case) was composed of teeth with periapical lesions. The number of teeth with and without posts in each group was recorded. Three calibrated examiners analyzed the radiographs visually under X4 magnification. Results: In Group 1, 28 (65.1%) out of 43 teeth were restored with posts. In Group 2, 24 (82.8%) out of 29 teeth had intra-radicular posts. The interpretation of chi-square test showed that these percentages were not significantly different (x²=2.687; p=0.101). Odds ratio was 2.571 (0.815-8.118), which indicates that there was no statistically significant association between periapical lesions and posts. Conclusion: Intra-radicular posts placed in endodontically treated teeth were not a significant risk factor for development of periapical lesions in the practice where the cohort of patients was treated
Complicated skin, skin structure and soft tissue infections - are we threatened by multi-resistant pathogens?
Tissue infections or skin, skin structure, and deep seated soft tissue infections are general terms for infections of the entire skin layer including the subcutaneous and muscle tissue layers and their respective fascia structures. Infections of the different mediastinal fascias (mediastinitis) and retroperitoneal fascia infections also belong to this category. Due to the variability of their clinical presentation, skin and soft tissue infections can be classified according to different features. The following aspects can be used for classification
Multiple populations in globular clusters. Lessons learned from the Milky Way globular clusters
Recent progress in studies of globular clusters has shown that they are not
simple stellar populations, being rather made of multiple generations. Evidence
stems both from photometry and spectroscopy. A new paradigm is then arising for
the formation of massive star clusters, which includes several episodes of star
formation. While this provides an explanation for several features of globular
clusters, including the second parameter problem, it also opens new
perspectives about the relation between globular clusters and the halo of our
Galaxy, and by extension of all populations with a high specific frequency of
globular clusters, such as, e.g., giant elliptical galaxies. We review progress
in this area, focusing on the most recent studies. Several points remain to be
properly understood, in particular those concerning the nature of the polluters
producing the abundance pattern in the clusters and the typical timescale, the
range of cluster masses where this phenomenon is active, and the relation
between globular clusters and other satellites of our Galaxy.Comment: In press (The Astronomy and Astrophysics Review
A Triad of Lys12, Lys41, Arg78 Spatial Domain, a Novel Identified Heparin Binding Site on Tat Protein, Facilitates Tat-Driven Cell Adhesion
Tat protein, released by HIV-infected cells, has a battery of important biological effects leading to distinct AIDS-associated pathologies. Cell surface heparan sulfate protoglycans (HSPGs) have been accepted as endogenous Tat receptors, and the Tat basic domain has been identified as the heparin binding site. However, findings that deletion or substitution of the basic domain inhibits but does not completely eliminate Tat–heparin interactions suggest that the basic domain is not the sole Tat heparin binding site. In the current study, an approach integrating computational modeling, mutagenesis, biophysical and cell-based assays was used to elucidate a novel, high affinity heparin-binding site: a Lys12, Lys41, Arg78 (KKR) spatial domain. This domain was also found to facilitate Tat-driven β1 integrin activation, producing subsequent SLK cell adhesion in an HSPG-dependent manner, but was not involved in Tat internalization. The identification of this new heparin binding site may foster further insight into the nature of Tat-heparin interactions and subsequent biological functions, facilitating the rational design of new therapeutics against Tat-mediated pathological events
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