Influence of Framework Material and Posterior Implant Angulation in Full-Arch All-on-4 Implant-Supported Prosthesis Stress Concentration

This study evaluated the influence of distal implants angulation and framework material in the stress concentration of an All-on-4 full-arch prosthesis. A full-arch implant-supported prosthesis 3D model was created with different distal implant angulations and cantilever arms (30° with 10-millimeter cantilever; 45° with 10-millimeter cantilever and 45° with 6-millimeter cantilever) and framework materials (Cobalt–chrome [CoCr alloy], Yttria-stabilized tetragonal zirconia polycrystal [Y-TZP] and polyetheretherketone [PEEK]). Each solid was imported to computer-aided engineering software, and tetrahedral elements formed the mesh. Material properties were assigned to each solid with isotropic and homogeneous behavior. The contacts were considered bonded. A vertical load of 200 N was applied in the distal region of the cantilever arm, and stress was evaluated in Von Misses (σVM) for prosthesis components and the Maximum (σMAX) and Minimum (σMIN) Principal Stresses for the bone. Distal implants angled in 45° with a 10-millimeter cantilever arm showed the highest stress concentration for all structures with higher stress magnitudes when the PEEK framework was considered. However, distal implants angled in 45° with a 6-millimeter cantilever arm showed promising mechanical responses with the lowest stress peaks. For the All-on-4 concept, a 45° distal implants angulation is only beneficial if it is possible to reduce the cantilever’s length; otherwise, the use of 30° should be considered. Comparing with PEEK, the YTZP and CoCr concentrated stress in the framework structure, reducing the stress in the prosthetic screw.

Sneddon’s Syndrome as rare and underdiagnosed cause of stroke: about two cases / A Síndrome de Sneddon como causa rara e subdiagnosticada de AVC: cerca de dois casos

Case 1. Female, 27 years old, with migraine with aura. Use of combined contraceptive therapy. She presented visual and cutaneous complaints for eight months, using prednisone 60mg/day due to the hypothesis of systemic vasculitis. On examination, right temporal hemianopsia, normal fundus of the eye, Raynaud ‘s phenomenon with necrosis stitches in fingers and livedo were noted. Brain MRI with diffusion restriction in the left occipital lobe, hypersignal foci in the parietal lobe, and head of the left caudate nucleus. Reticular Livedo (RL) compatible biopsy. Anticardiolipin IgM (13.3 U/mL), ESR (47mm/h in the 1st hour and 52mm/h in the 2nd hour), and VDRL 1:8 reagents. Normal CSF. Initially treated with warfarin, she has been using rivaroxaban for two years, remaining asymptomatic. Case 2. Female, 39 years old, with a report of sudden dysarthria and right hemiparesis, with a previous episode of vertigo. A lumbosacral spine MRI was performed, presenting no alterations. Normal CSF. Antiphospholipid antibodies: Beta-2-glycoprotein I IgM 21 UR/mL and IgG 9 UR/mL, lupus anticoagulant 0.98, anticardiolipin IgG 9.4 GPL and IgM 31 MPL. Cranial MRI showed old ischemic gaps and hyperintense areas on T2/FLAIR with diffusion restriction affecting the left paramedian portion of the pons, related to acute stroke. Presence of livedo in the distal region of the limbs. In current use of warfarin 7.5mg/day, presenting remission of symptoms. Discussion: Sneddon Syndrome (SS) is a non-inflammatory thrombotic vasculopathy characterized by the concomitant presence of livedo reticularis and stroke. Neurological manifestations are present in up to 77% of cases. It is more prevalent in women between 20 and 42 years old. Treatment is aimed at preventing potentially serious, disabling, and even fatal new vascular events. Final Comments: SS is a rare syndrome that probably results from a series of acquired or congenital hemostatic abnormalities that preferentially involve the cutaneous and cerebral vascular beds. Although it has no specific biomarker, there are reports associating SS with antiphospholipid antibodies and VDRL reactor. Clinical presentation, laboratory findings and skin biopsy associated with an excellent response to anticoagulant treatment were fundamental in the diagnostic elucidation.

Redescription of Ektaphelenchoides compsi Baujard, 1984 (Tylenchina: Aphelenchoididae) isolated from Pinus massoniana in Fujian Province, China

Summary Ektaphelenchoides compsi is redescribed morphologically with new molecular characterisation. It was isolated from a dead Pinus massoniana tree in Ningde City, Fujian Province, China. Detailed morphology of the spicule, female gonad, hemizonid position, arrangement of male caudal papillae and female tail terminus shape are documented. It is characterised by a lateral field with three lines (forming two bands), tripartite stylet 17.8 (17.0-19.4) μm long without basal thickenings, metacorpus rectangular with anterior 40% granular and posterior part weakly muscular, metacorpal valve slightly posterior to middle of metacorpus, excretory pore at level of nerve ring, vagina with thickened walls and strongly developed muscular bundles, vulval lips slightly protuberant, vulval flap absent, distal region of post-vulval uterine sac appearing as a weakly developed oogonia, anus and rectum indistinct, female posterior part (‘tail’) dorsally convex, conical, terminal region contracted into a bluntly pointed tip. The spicules are arcuate, 15.6 (14.3-16.3) μm along the chord, lamina smoothly curved to distal end, capitulum slightly concave, condylus well-developed with broadly rounded tip and slightly depressed at dorsal end, rostrum triangular with finely rounded tip, cucullus absent, and with seven caudal papillae present. The near full length 18S and 28S D2-D3 regions of rRNA genes sequences were characterised. The phylogenetic analyses revealed that the Fujian population of E. compsi grouped with the Zhejiang population of E. compsi, both being morphologically identical.

Mg2+-dependent conformational rearrangements of CRISPR-Cas12a R-loop complex are mandatory for complete double-stranded DNA cleavage

CRISPR-Cas12a, an RNA-guided DNA targeting endonuclease, has been widely used for genome editing and nucleic acid detection. As part of the essential processes for both of these applications, the two strands of double-stranded DNA are sequentially cleaved by a single catalytic site of Cas12a, but the mechanistic details that govern the generation of complete breaks in double-stranded DNA remain to be elucidated. Here, using single-molecule fluorescence resonance energy transfer assay, we identified two conformational intermediates that form consecutively following the initial cleavage of the nontarget strand. Specifically, these two intermediates are the result of further unwinding of the target DNA in the protospacer-adjacent motif (PAM)–distal region and the subsequent binding of the target strand to the catalytic site. Notably, the PAM-distal DNA unwound conformation was stabilized by Mg2+ ions, thereby significantly promoting the binding and cleavage of the target strand. These findings enabled us to propose a Mg2+-dependent kinetic model for the mechanism whereby Cas12a achieves cleavage of the target DNA, highlighting the presence of conformational rearrangements for the complete cleavage of the double-stranded DNA target.

Hind-Foot Synovial Sarcoma Treated With Wide Resection and Sural Fasciocutaneous Flap – A Case Report

Synovial sarcoma comprises about 5% to 10% of soft tissue sarcomas. Initial growth is often slow and a small circumscribed tumour may misleadingly appear to a benign lesion by clinical examination and imaging, occurring in up to 50% of cases. The modalities of treatment of foot malignant conditions depend on histological diagnosis and staging. A radical surgical procedure in the distal region of the lower limb is often difficult due to a limited soft-tissue situation and can result in soft-tissue defects. Plastic surgical techniques remain particularly indispensable in the treatment of such distal tumors. Authors present a hindfoot synovial sarcoma, diagnosed with a incisional biopsy, in which a wide margin surgery was achieved and a limb salvage was permitted by a sural fasciocutaneous flap.

Dynamic Allostery Highlights the Evolutionary Differences between the CoV-1 and CoV-2 Main Proteases

ABSTRACTThe SARS-CoV-2 coronavirus has become one of the most immediate and widely-studied systems since its identification and subsequent global outbreak from 2019-2020. In an effort to understand the biophysical changes as a result of mutations, the mechanics of multiple different proteins within the SARS-CoV-2 virus have been studied and compared with SARS-CoV-1. Focusing on the main protease (mPro), we first explored the long range dynamic-relationship, particularly in cross-chain dynamics, using the Dynamic Coupling Index (DCI) to investigate the dynamic coupling between the catalytic site residues and the rest of the protein, both inter and intra chain for the CoV-1 and CoV-2 mPro. We found that there is significant cross-chain coupling between these active sites and distal residues in the CoV-2 mPro but it was missing in CoV-1. The enhanced long distance interactions, particularly between the two chains, suggest subsequently enhanced cooperativity for CoV-2. A further comparative analysis of the dynamic flexibility using the Dynamic Flexibility Index (DFI) between the CoV-1 and CoV-2 mPros shows that the inhibitor binding near active sites induces change in flexibility to a distal region of the protein, opposite in behavior between the two systems; this region becomes more flexible upon inhibitor binding in CoV-1 while it becomes less flexible in the CoV-2 mPro. Upon inspection, we show that, on average, the dynamic flexibility of the sites substituted from CoV-1 to CoV-2 changes significantly less than the average calculated across all residues within the structure, indicating that the differences in behaviors between the two systems is likely the result of allosteric influence, where the new substitutions in COV-2 induce flexibility and dynamical changes elsewhere in the structure.SIGNIFICANCEHere we have conducted a comparative analysis between the SARS-CoV-1 and SARS-CoV-2 mPro systems to shed mechanistic insight on the biophysical changes associated with the mutations between these two enzymes. Our work shows that the CoV-2 mPro system exhibits enhanced cross-chain communication between catalytic site residues and the rest of the structure. Further, both dynamic coupling and dynamic flexibility analyses indicates that, largely, the dynamic changes as evaluated by DCI and DFI occur at sites other than the mutation sites themselves, indicating that the functional differences between these two proteins are a result of dynamic allostery

Prenatal findings of 2q13 Duplication and Deletion: Further Evidence for Lack of Phenotypic-Genotype Correlation

2q13 CNV was associated with various diseases, with a lack of consensus. By CMA analysis, we found that four fetuses had deletion in the proximal region of 2q13, one had duplication, and one had duplication in the distal region of 2q13; however, they had variable outcomes.

Trop2 Forms a Stable Dimer with Significant Structural Differences within the Membrane-Distal Region as Compared to EpCAM

Trop2 is a cell-surface transmembrane glycoprotein involved in the maintenance of epithelial tissue integrity and is an important carcinoma marker. It shares similar claudin-interaction capacity with its paralogue EpCAM, and both are implicated in signaling triggered by proteolytic cleavage within the ectodomain. However, the cell proliferation-regulating interactions with IGF-1, neuregulin-1, and α5β1 integrin appear to be Trop2-specific. To illuminate the structural differences between Trop2 and EpCAM, we report the first crystal structure of a Trop2 ectodomain dimer and compare it to the analogous part of EpCAM. While the overall fold of the two proteins is similar, the dimers differ. In Trop2, the inter-subunit contacts are more extensive than in EpCAM, and there are two major differences in the membrane-distal regions. The immunogenic N-terminal domain is in Trop2 almost colinear with the dimer interface plain and consequently more laterally exposed, and the cleft of yet unknown functionality between the two subunits is almost absent. Furthermore, the site of initial signaling-associated proteolytic cleavage in Trop2 is accessible in the dimeric state, while in EpCAM dimer destabilization is required. The structural differences highlight the divergent evolutionary path of the two proteins and pave the way for their structure-based utilization in therapy.

Complete duplication of the urethra in a boy with epispadias

Duplication of the urethra is a rare abnormality that can occur with other urogenital tract congenital pathologies. Ischemia at embryogenesis, urogenital sinus defect, Muller`s duct anomaly and incomplete mesodermal fusion are the pathophysiological mechanisms of the pathology onset. Duplication of the urethra diagnostics is based on clinical examination, disease anamnesis, urethrography and magnetic resonance imaging. It is nessessary to consider Effmann and Leibowitz classification, urethras and prostate location and urethral orifice distance on operation of additional urethra removing. Clinical case. Presenting a clinical case of a boy with grade I epispadias and complete duplication of the urethra. Urination was maintained and was performed from the dorsal-epispadic urethra, the ventral urethra was obliterated in the distal region. According to the data of magnetic resonance imaging: double urethra is traced, dorsal – comes out from the anterior parts of the bladder wall, continues along the dorsal surface under the dorsal neurovascular bundle, above the cavernous bodies. The urethra opening is traced at the level of the upper surface of the head of the penis. The distal / ventral urethra comes out from the posterior parts of the lower bladder wall, typically continues down through the prostate embryo, rotated forward between of the corporas cavernosas stipes, and had a typical location with except for the level of the penis head, where it bends and merges with the dorsal urethra, which opens with a single opening. The surgery of excision of an additional urethra on child was performed. During the examination of the child of 6 months after surgery: urination with one stream from the ventral urethra at the apex of the head of the penis, stream freely passes the Nelaton catheter No. 10, child holds urine, there was no complaints. Performing of the next stage of the operation (penis plastic surgery) is planned after 1 year of the previous stage. Conclusions. In cases of epispadias is possible a congenital defect – a complete douplication of the urethra with the ventral urethra obliteration at the top of the head, which may not be determined in epispadias surgery preparation. Doubling of the urethra in boys requires magnetic resonance imaging for a better orientation in the defect anatomy and to determine the tactics of further surgical treatment. The research was carried out in accordance with the principles of the Helsinki declaration. The informed consent of the patient was obtained for conducting the studies. No conflict of interest was declared by the authors. Key words: complete duplication of the urethra, surgical treatment, children.

A Simple Method for Automatic 3D Reconstruction of Coronary Arteries From X-Ray Angiography

Automatic three-dimensional (3-D) reconstruction of the coronary arteries (CA) from medical imaging modalities is still a challenging task. In this study, we present a deep learning-based method of automatic identification of the two ends of the vessel from X-ray coronary angiography (XCA). We also present a method of using template models of CA in matching the two-dimensional segmented vessels from two different angles of XCA. For the deep learning network, we used a U-net consisting of an encoder (Resnet) and a decoder. The two ends of the vessel were manually labeled to generate training images. The network was trained with 2,342, 1,907, and 1,523 labeled images for the left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA), respectively. For template models of CA, ten reconstructed 3-D models were averaged for each artery. The accuracy of correspondence using template models was compared with that of manual matching. The deep learning network pointed the proximal region (20% of the total length) in 97.7, 97.5, and 96.4% of 315, 201, and 167 test images for LAD, LCX, and RCA, respectively. The success rates in pointing the distal region were 94.9, 89.8, and 94.6%, respectively. The average distances between the projected points from the reconstructed 3-D model to the detector and the points on the segmented vessels were not statistically different between the template and manual matchings. The computed FFR was not significantly different between the two matchings either. Deep learning methodology is feasible in identifying the two ends of the vessel in XCA, and the accuracy of using template models is comparable to that of manual correspondence in matching the segmented vessels from two angles.