scholarly journals Repair Mechanism of Osteochondral Defect Promoted by Bioengineered Chondrocyte Sheet

2015 ◽  
Vol 21 (5-6) ◽  
pp. 1131-1141 ◽  
Author(s):  
Ryo Shimizu ◽  
Naosuke Kamei ◽  
Nobuo Adachi ◽  
Michio Hamanishi ◽  
Goki Kamei ◽  
...  
Keyword(s):  
Osteochondral Defect ◽  
Repair Mechanism ◽  
Chondrocyte Sheet

3D Printing as a Way of Integrating Mathematical Models in Arthroscopic Knee Surgery

2018 ◽  
Vol 69 (9) ◽  
pp. 2501-2507
Author(s):  
Anca Plavitu ◽  
Mark Edward Pogarasteanu ◽  
Marius Moga ◽  
Mircea Lupusoru ◽  
Florentina Ionita Radu ◽  
...  
Keyword(s):  
Knee Joint ◽  
Osteochondral Defect ◽  
Surgical Intervention ◽  
Operating Time ◽  
Vascular Pathology ◽  
Osteochondral Lesions ◽  
Joint Surfaces ◽  
Novel Method ◽  
Technological Means ◽  
Arthroscopic Knee

Our objective is to develop a novel method of approaching the arthroscopic treatment of osteochondral lesions within the knee joint by using mathematics as a way of understanding the geometry involved in the knee, both in normal and degenerated knee joint surfaces. Bone and cartilage lesions are frequent, whether as a result of trauma, degenerative pathology, vascular pathology (osteocondritis dissecans) or tumoral. In all cases, a defect can be repaired arthroscopically, if it has manageable dimensions and if the surgeon has the technological means and the necessary skills, through the use of grafts (autografts or allografts). Alternatively, a lesion that may be approached arthroscopically initially could prove to be too great for repair and may need a second intervention for reconstruction with an endoprosthesis. We aim to further deepen the surgeon�s understanding of this pathology, through the use of 3D technology as a way of representing the osteochondral defect. Thus, its dimensions and position may be better understood, and the surgical intervention may be better planned out, potentially resulting in a shorter operating time and an overall superior outcome for the patient, and even potentially diminishing the number of unnecessary surgeries performed.

scholarly journals Discovery of pyrano[2,3-d]pyrimidine-2,4-dione derivatives as novel PARP-1 inhibitors: design, synthesis and antitumor activity

RSC Advances ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 4454-4464
Author(s):  
Nour E. A. Abd El-sattar ◽  
Eman H. K. Badawy ◽  
Eman Z. Elrazaz ◽  
Nasser S. M. Ismail
Keyword(s):  
Cell Death ◽  
Dna Repair ◽  
Antitumor Activity ◽  
Cancer Cell ◽  
Cytotoxic Agents ◽  
Repair Mechanism ◽  
Design Synthesis ◽  
Parp 1

PARP-1 are involved in DNA repair damage and so PARP-1 inhibitors have been used as potentiators in combination with DNA damaging cytotoxic agents to compromise the cancer cell DNA repair mechanism, resulting in genomic dysfunction and cell death.

Structural insights into the repair mechanism of AGT for methyl-induced DNA damage

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rajendra P. Koirala ◽  
Rudramani Pokhrel ◽  
Prabin Baral ◽  
Purushottam B. Tiwari ◽  
Prem P. Chapagain ◽  
...  
Keyword(s):  
Covalent Bond ◽  
Cancer Therapeutics ◽  
Md Simulations ◽  
Structural Features ◽  
Umbrella Sampling ◽  
Repair Mechanism ◽  
Structural Investigations ◽  
Methylated Dna ◽  
Dna Base ◽  
Dna Alkyltransferase

Abstract Methylation induced DNA base-pairing damage is one of the major causes of cancer. O6-alkylguanine-DNA alkyltransferase (AGT) is considered a demethylation agent of the methylated DNA. Structural investigations with thermodynamic properties of the AGT-DNA complex are still lacking. In this report, we modeled two catalytic states of AGT-DNA interactions and an AGT-DNA covalent complex and explored structural features using molecular dynamics (MD) simulations. We utilized the umbrella sampling method to investigate the changes in the free energy of the interactions in two different AGT-DNA catalytic states, one with methylated GUA in DNA and the other with methylated CYS145 in AGT. These non-covalent complexes represent the pre- and post-repair complexes. Therefore, our study encompasses the process of recognition, complex formation, and separation of the AGT and the damaged (methylated) DNA base. We believe that the use of parameters for the amino acid and nucleotide modifications and for the protein-DNA covalent bond will allow investigations of the DNA repair mechanism as well as the exploration of cancer therapeutics targeting the AGT-DNA complexes at various functional states as well as explorations via stabilization of the complex.

scholarly journals Comparative analyses of two primate species diverged by more than 60 million years show different rates but similar distribution of genome-wide UV repair events

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Umit Akkose ◽  
Veysel Ogulcan Kaya ◽  
Laura Lindsey-Boltz ◽  
Zeynep Karagoz ◽  
Adam D. Brown ◽  
...  
Keyword(s):  
Nucleotide Excision Repair ◽  
Cell Lines ◽  
Human Cell ◽  
Excision Repair ◽  
Mouse Lemur ◽  
Repair Mechanism ◽  
Damage Repair ◽  
Genome Wide ◽  
Repair Efficiency ◽  
Nucleotide Excision

Abstract Background Nucleotide excision repair is the primary DNA repair mechanism that removes bulky DNA adducts such as UV-induced pyrimidine dimers. Correspondingly, genome-wide mapping of nucleotide excision repair with eXcision Repair sequencing (XR-seq), provides comprehensive profiling of DNA damage repair. A number of XR-seq experiments at a variety of conditions for different damage types revealed heterogenous repair in the human genome. Although human repair profiles were extensively studied, how repair maps vary between primates is yet to be investigated. Here, we characterized the genome-wide UV-induced damage repair in gray mouse lemur, Microcebus murinus, in comparison to human. Results We derived fibroblast cell lines from mouse lemur, exposed them to UV irradiation, and analyzed the repair events genome-wide using the XR-seq protocol. Mouse lemur repair profiles were analyzed in comparison to the equivalent human fibroblast datasets. We found that overall UV sensitivity, repair efficiency, and transcription-coupled repair levels differ between the two primates. Despite this, comparative analysis of human and mouse lemur fibroblasts revealed that genome-wide repair profiles of the homologous regions are highly correlated, and this correlation is stronger for highly expressed genes. With the inclusion of an additional XR-seq sample derived from another human cell line in the analysis, we found that fibroblasts of the two primates repair UV-induced DNA lesions in a more similar pattern than two distinct human cell lines do. Conclusion Our results suggest that mouse lemurs and humans, and possibly primates in general, share a homologous repair mechanism as well as genomic variance distribution, albeit with their variable repair efficiency. This result also emphasizes the deep homologies of individual tissue types across the eukaryotic phylogeny.

scholarly journals Effect of Oral Losartan on Orthobiologics: Implications for Platelet-Rich Plasma and Bone Marrow Concentrate—A Rabbit Study

2020 ◽  
Vol 21 (19) ◽  
pp. 7374
Author(s):  
Gilberto Y. Nakama ◽  
Sabrina Gonzalez ◽  
Polina Matre ◽  
Xiaodong Mu ◽  
Kaitlyn E. Whitney ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Osteochondral Defect ◽  
Platelet Rich Plasma ◽  
Control Group ◽  
Bone Marrow Concentrate ◽  
Significant Difference ◽  
Losartan Group ◽  
Group 2 ◽  
And Control ◽  
Tgf Β1

Recent efforts have focused on customizing orthobiologics, such as platelet-rich plasma (PRP) and bone marrow concentrate (BMC), to improve tissue repair. We hypothesized that oral losartan (a TGF-β1 blocker with anti-fibrotic properties) could decrease TGF-β1 levels in leukocyte-poor PRP (LP-PRP) and fibrocytes in BMC. Ten rabbits were randomized into two groups (N = 5/group): osteochondral defect + microfracture (control, group 1) and osteochondral defect + microfracture + losartan (losartan, group 2). For group 2, a dose of 10mg/kg/day of losartan was administrated orally for 12 weeks post-operatively. After 12 weeks, whole blood (WB) and bone marrow aspirate (BMA) samples were collected to process LP-PRP and BMC. TGF-β1 concentrations were measured in WB and LP-PRP with multiplex immunoassay. BMC cell populations were analyzed by flow cytometry with CD31, CD44, CD45, CD34, CD146 and CD90 antibodies. There was no significant difference in TGF-β1 levels between the losartan and control group in WB or LP-PRP. In BMC, the percentage of CD31+ cells (endothelial cells) in the losartan group was significantly higher than the control group (p = 0.008), while the percentage of CD45+ cells (hematopoietic cells-fibrocytes) in the losartan group was significantly lower than the control group (p = 0.03).

scholarly journals Incremental Construction of Generalized Voronoi Diagrams on Pointerless Quadtrees

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Quanjun Yin ◽  
Long Qin ◽  
Xiaocheng Liu ◽  
Yabing Zha
Keyword(s):  
Voronoi Diagrams ◽  
Surrounding Area ◽  
Repair Mechanism ◽  
Local Repair ◽  
Order Of Magnitude ◽  
Generalized Voronoi Diagrams ◽  
Incremental Construction ◽  
Coarse To Fine ◽  
Multiple Granularities ◽  
Magnitude Improvement

In robotics, Generalized Voronoi Diagrams (GVDs) are widely used by mobile robots to represent the spatial topologies of their surrounding area. In this paper we consider the problem of constructing GVDs on discrete environments. Several algorithms that solve this problem exist in the literature, notably the Brushfire algorithm and its improved versions which possess local repair mechanism. However, when the area to be processed is very large or is of high resolution, the size of the metric matrices used by these algorithms to compute GVDs can be prohibitive. To address this issue, we propose an improvement on the current algorithms, using pointerless quadtrees in place of metric matrices to compute and maintain GVDs. Beyond the construction and reconstruction of a GVD, our algorithm further provides a method to approximate roadmaps in multiple granularities from the quadtree based GVD. Simulation tests in representative scenarios demonstrate that, compared with the current algorithms, our algorithm generally makes an order of magnitude improvement regarding memory cost when the area is larger than210×210. We also demonstrate the usefulness of the approximated roadmaps for coarse-to-fine pathfinding tasks.

Sign in / Sign up

Export Citation Format

Share Document