Foot-and-mouth disease virus 2C is a hexameric AAA+ protein with a coordinated ATP hydrolysis mechanism.

Foot-and-mouth disease virus (FMDV), a positive sense, single-stranded RNA virus, causes a highly contagious disease in cloven-hoofed livestock. Like other picornaviruses, FMDV has a conserved 2C protein assigned to the superfamily 3 helicases a group of AAA+ ATPases that has a predicted N-terminal membrane-binding amphipathic helix attached to the main ATPase domain. In infected cells, 2C is involved in the formation of membrane vesicles, where it co-localizes with viral RNA replication complexes, but its precise role in virus replication has not been elucidated. We show here that deletion of the predicted N-terminal amphipathic helix enables overexpression in Escherichia coli of a highly soluble truncated protein, 2C(34–318), that has ATPase and RNA binding activity. ATPase activity was abrogated by point mutations in the Walker A (K116A) and B (D160A) motifs and Motif C (N207A) in the active site. Unliganded 2C(34–318) exhibits concentration-dependent self-association to yield oligomeric forms, the largest of which is tetrameric. Strikingly, in the presence of ATP and RNA, FMDV 2C(34–318) containing the N207A mutation, which binds but does not hydrolyze ATP, was found to oligomerize specifically into hexamers. Visualization of FMDV 2C-ATP-RNA complexes by negative stain electron microscopy revealed hexameric ring structures with 6-fold symmetry that are characteristic of AAA+ ATPases. ATPase assays performed by mixing purified active and inactive 2C(34–318) subunits revealed a coordinated mechanism of ATP hydrolysis. Our results provide new insights into the structure and mechanism of picornavirus 2C proteins that will facilitate new investigations of their roles in infection

УСТРАНЕНИЕ ДЕФЕКТОВ ОСНОВАНИЯ ЧЕРЕПА И СРЕДНЕЙ ЗОНЫ ЛИЦА ПОСЛЕ ХИРУРГИЧЕСКОГО ЛЕЧЕНИЯ РАСПРОСТРАНЕННЫХ КРАНИОМАКСИЛЛЯРНЫХ ОПУХОЛЕЙ

Introduction. Performance the radical surgical treatment in patients with widespread cranio-maxillary tumors is followed by appearance of extensive defects.Objective. To explore the possibility of the applying the basic methods of eliminating defects cranio-maxillary localization after surgical treatment of tumors and their impact on quality of life and survival.Material and methods. The results of surgical treatment of 94 patients with the widespread cranio-maxillary tumors, depending on the performed type of the surgery and method of eliminating postoperative defects were analyzed.Results. Efficiency of different methods of reconstruction of defects of the midface and anterior skull base and their impact on quality of life and survival after the surgery were estimated. The use of general oncological methods in combination with the methods of the primary effectively correction of formed defects allows to achieve better results in the treatment of patients with widespread cranio-maxillary tumors. .Введение. Выполнение радикального оперативного пособия у пациентов с распространенными краниомаксиллярными опухолями сопровождается возникновением обширных дефектов.Цель исследования – изучить возможности применения основных методик устранения дефектов краниомаксиллярной локализации после хирургического лечения опухолей, их влияние на качество жизни и выживаемость.Материал и методы. Проанализированы результаты хирургического лечения 94 больных с распространенными краниомаксиллярными опухолями в зависимости от характера выполненного оперативного вмешательства, применяемой методики устранения послеоперационных дефектов.Результаты. Выполнена оценка эффективности использования различных методов в реконструкции дефектов средней зоны лица и основания черепа после хирургического лечения, их влияния на качество жизни и выживаемость. Применение онкологических методик в сочетании с первичным устранением образовавшихся дефектов позволяет добиться более высоких результатов лечения краниомаксиллярных опухолей

An Expert Consensus Statement on the Management of Large Chondral and Osteochondral Defects in the Patellofemoral Joint

© The Author(s) 2020. Background: Cartilage lesions of the patellofemoral joint constitute a frequent abnormality. Patellofemoral conditions are challenging to treat because of complex biomechanics and morphology. Purpose: To develop a consensus statement on the functional anatomy, indications, donor graft considerations, surgical treatment, and rehabilitation for the management of large chondral and osteochondral defects in the patellofemoral joint using a modified Delphi technique. Study Design: Consensus statement. Methods: A working group of 4 persons generated a list of statements related to the functional anatomy, indications, donor graft considerations, surgical treatment, and rehabilitation for the management of large chondral and osteochondral defects in the patellofemoral joint to form the basis of an initial survey for rating by a group of experts. The Metrics of Osteochondral Allografts (MOCA) expert group (composed of 28 high-volume cartilage experts) was surveyed on 3 occasions to establish a consensus on the statements. In addition to assessing agreement for each included statement, experts were invited to propose additional statements for inclusion or to suggest modifications of existing statements with each round. Predefined criteria were used to refine statement lists after each survey round. Statements reaching a consensus in round 3 were included within the final consensus document. Results: A total of 28 experts (100% response rate) completed 3 rounds of surveys. After 3 rounds, 36 statements achieved a consensus, with over 75% agreement and less than 20% disagreement. A consensus was reached in 100.00% of the statements relating to functional anatomy of the patellofemoral joint, 88.24% relating to surgical indications, 100.00% relating to surgical technical aspects, and 100.00% relating to rehabilitation, with an overall consensus of 95.5%. Conclusion: This study established a strong expert consensus document relating to the functional anatomy, surgical indications, donor graft considerations for osteochondral allografts, surgical technical aspects, and rehabilitation concepts for the management of large chondral and osteochondral defects in the patellofemoral joint. Further research is required to clinically validate the established consensus statements and better understand the precise indications for surgery as well as which techniques and graft processing/preparation methods should be used based on patient- and lesion-specific factors

Direct Interaction between Two Viral Proteins, the Nonstructural Protein 2CATPase and the Capsid Protein VP3, Is Required for Enterovirus Morphogenesis

In spite of decades-long studies, the mechanism of morphogenesis of plus-stranded RNA viruses belonging to the genus Enterovirus of Picornaviridae, including poliovirus (PV), is not understood. Numerous attempts to identify an RNA encapsidation signal have failed. Genetic studies, however, have implicated a role of the non-structural protein 2CATPase in the formation of poliovirus particles. Here we report a novel mechanism in which protein-protein interaction is sufficient to explain the specificity in PV encapsidation. Making use of a novel “reporter virus”, we show that a quasi-infectious chimera consisting of the capsid precursor of C-cluster coxsackie virus 20 (C-CAV20) and the nonstructural proteins of the closely related PV translated and replicated its genome with wild type kinetics, whereas encapsidation was blocked. On blind passages, encapsidation of the chimera was rescued by a single mutation either in capsid protein VP3 of CAV20 or in 2CATPase of PV. Whereas each of the single-mutation variants expressed severe proliferation phenotypes, engineering both mutations into the chimera yielded a virus encapsidating with wild type kinetics. Biochemical analyses provided strong evidence for a direct interaction between 2CATPase and VP3 of PV and CAV20. Chimeras of other C-CAVs (CAV20/CAV21 or CAV18/CAV20) were blocked in encapsidation (no virus after blind passages) but could be rescued if the capsid and 2CATPase coding regions originated from the same virus. Our novel mechanism explains the specificity of encapsidation without apparent involvement of an RNA signal by considering that (i) genome replication is known to be stringently linked to translation, (ii) morphogenesis is known to be stringently linked to genome replication, (iii) newly synthesized 2CATPase is an essential component of the replication complex, and (iv) 2CATPase has specific affinity to capsid protein(s). These conditions lead to morphogenesis at the site where newly synthesized genomes emerge from the replication complex

Deletion Mutants of VPg Reveal New Cytopathology Determinants in a Picornavirus

BACKGROUND: Success of a viral infection requires that each infected cell delivers a sufficient number of infectious particles to allow new rounds of infection. In picornaviruses, viral replication is initiated by the viral polymerase and a viral-coded protein, termed VPg, that primes RNA synthesis. Foot-and-mouth disease virus (FMDV) is exceptional among picornaviruses in that its genome encodes 3 copies of VPg. Why FMDV encodes three VPgs is unknown. METHODOLOGY AND PRINCIPAL FINDINGS: we have constructed four mutant FMDVS that encode only one VPG: either VPg(1), VPg(3), or two chimeric versions containing part of VPg(1) and VPg(3). All mutants, except that encoding only VPg(1), were replication-competent. Unexpectedly, despite being replication-competent, the mutants did not form plaques on BHK-21 cell monolayers. The one-VPg mutant FMDVs released lower amounts of encapsidated viral RNA to the extracellular environment than wild type FMDV, suggesting that deficient plaque formation was associated with insufficient release of infectious progeny. Mutant FMDVs subjected to serial passages in BHK-21 cells regained plaque-forming capacity without modification of the number of copies of VPg. Substitutions in non-structural proteins 2C, 3A and VPg were associated with restoration of plaque formation. Specifically, replacement R55W in 2C was repeatedly found in several mutant viruses that had regained competence in plaque development. The effect of R55W in 2C was to mediate an increase in the extracellular viral RNA release without a detectable increase of total viral RNA that correlated with an enhanced capacity to alter and detach BHK-21 cells from the monolayer, the first stage of cell killing. CONCLUSIONS: The results link the VPg copies in the FMDV genome with the cytopathology capacity of the virus, and have unveiled yet another function of 2C: modulation of picornavirus cell-to-cell transmission. Implications for picornaviruses pathogenesis are discussed

Urethral carcinoma metastatic to bone: a case report and literature review.

Distant urethral carcinoma metastasis is a very rare event. The following discussion presents a unique case of urethral carcinoma (adenocarcinoma) metastatic to bone and reviews the literature regarding this condition

Urethral carcinoma metastatic to bone: a case report and literature review.

Distant urethral carcinoma metastasis is a very rare event. The following discussion presents a unique case of urethral carcinoma (adenocarcinoma) metastatic to bone and reviews the literature regarding this condition

Radial head fractures: MRI evaluation of associated injuries

The purpose of this study was to evaluate the incidence of combined osteochondral and ligamentous injuries by magnetic resonance imaging (MRI) in 24 patients with an acute radial head fracture (Mason type II and III) without documented dislocation or tenderness at the distal radioulnar joint. Elbow radiographs (anteroposterior and lateral views) were obtained on all patients as well as magnetic resonance images in the sagittal, coronal, axial, axial oblique, and coronal oblique planes with the injured elbow in a splint. The incidence of associated injuries revealed by MRI was medial collateral ligament not intact in 13 of 24 (54.16%), lateral ulnar collateral ligament not intact in 18 of 24 (80.1%), both collateral ligaments not intact in 12 of 24 (50%), capitellar osteochondral defects in 7 of 24 (29.1%), capitellar bone bruises in 23 of 24 (95.83%), and loose bodies in 22 of 24 (91.67%). A high level of suspicion should be used when one is treating displaced or comminuted radial head fractures, because concurrent osteochondral injuries and/or ligamentous injuries may be present