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Cancer Diagnosis & Prognosis 2022This study aimed to present a rare case of fibrous dysplasia (FD) in a healthy young adult man with a concomitant osteoporotic vertebral compression fracture. FD is a...
BACKGROUND/AIM
This study aimed to present a rare case of fibrous dysplasia (FD) in a healthy young adult man with a concomitant osteoporotic vertebral compression fracture. FD is a benign lesion of the bone characterized by replacement of the medullary component with fibro-osseous tissue that contains abnormally arranged trabeculae of immature woven bone. Recently it has been reported that several bone tumors including FD express the receptor activator of nuclear factor-kappa B (RANK) and its ligand (RANKL). Therefore, we hypothesized that FD contributed to osteoporosis, linked by the RANK-RANKL pathway of osteoclastogenesis.
CASE REPORT
We report the case of a healthy man with monostotic femoral fibrous dysplasia (FD) with concomitant 7 thoracic vertebra compression fracture due to osteoporosis [young adult mean (YAM) was 79% in bone mineral density (BMD)]. After curettage of the FD, artificial bone grafting in the cavity, and administration of alendronate sodium, BMD improved considerably within 9 months. FD is a benign bone condition in which abnormal fibrous tissue replaces normal bone. The axis of the receptor activator of nuclear factor-kappa B (RANK) and its ligand (RANKL) has been implicated in osteoporosis pathogenesis. RANKL immunohistochemical staining was performed, and strong staining of stromal cells was observed compared to other FD cases that showed weak to moderate staining.
CONCLUSION
The presence of FD might have contributed to the low BMD due to the RANK-RANKL axis acting as osteoclastogenesis stimulator.
PubMed: 35400000
DOI: 10.21873/cdp.10082 -
Theoretical Chemistry Accounts 2020We present a computational study of sub-picosecond nonadiabatic dynamics in a rhenium complex coupled electronically to a tryptophan (Trp) side chain of azurin, a...
We present a computational study of sub-picosecond nonadiabatic dynamics in a rhenium complex coupled electronically to a tryptophan (Trp) side chain of azurin, a prototypical protein used in the study of electron transfer in proteins. To gain a comprehensive understanding of the photoinduced processes in this system, we have carried out vertical excitation calculations at the TDDFT level of theory as well as nonadiabatic dynamics simulations using the surface hopping including arbitrary couplings (SHARC) method coupled to potential energy surfaces represented with a linear vibronic coupling model. The results show that the initial photoexcitation populates both singlet metal-to-ligand charge transfer (MLCT) and singlet charge-separated (CS) states, where in the latter an electron was transferred from the Trp amino acid to the complex. Subsequently, a complex mechanism of simultaneous intersystem crossing and electron transfer leads to the sub-picosecond population of triplet MLCT and triplet CS states. These results confirm the assignment of the sub-ps time constants of previous experimental studies and constitute the first computational evidence for the ultrafast formation of the charge-separated states in Re-sensitized azurin.
PubMed: 32214889
DOI: 10.1007/s00214-020-2555-6 -
Dalton Transactions (Cambridge, England... Jan 2024Cupredoxins are widely occurring copper-binding proteins with a typical Greek-key beta barrel fold. They are generally described as electron carriers that rely on a T1...
Cupredoxins are widely occurring copper-binding proteins with a typical Greek-key beta barrel fold. They are generally described as electron carriers that rely on a T1 copper centre coordinated by four ligands provided by the folded polypeptide. The discovery of novel cupredoxins demonstrates the high diversity of this family, with variations in terms of copper-binding ligands, copper centre geometry, redox potential, as well as biological function. AcoP is a periplasmic cupredoxin belonging to the iron respiratory chain of the acidophilic bacterium Acidithiobacillus ferrooxidans. AcoP presents original features, including high resistance to acidic pH and a constrained green-type copper centre of high redox potential. To understand the unique properties of AcoP, we undertook structural and biophysical characterization of wild-type AcoP and of two Cu-ligand mutants (H166A and M171A). The crystallographic structures, including native reduced AcoP at 1.65 Å resolution, unveil a typical cupredoxin fold. The presence of extended loops, never observed in previously characterized cupredoxins, might account for the interaction of AcoP with physiological partners. The Cu-ligand distances, determined by both X-ray diffraction and EXAFS, show that the AcoP metal centre seems to present both T1 and T1.5 features, in turn suggesting that AcoP might not fit well to the coupled distortion model. The crystal structures of two AcoP mutants confirm that the active centre of AcoP is highly constrained. Comparative analysis with other cupredoxins of known structures, suggests that in AcoP the second coordination sphere might be an important determinant of active centre rigidity due to the presence of an extensive hydrogen bond network. Finally, we show that other cupredoxins do not perfectly follow the coupled distortion model as well, raising the suspicion that further alternative models to describe copper centre geometries need to be developed, while the importance of rack-induced contributions should not be underestimated.
Topics: Azurin; Binding Sites; Copper; Ligands
PubMed: 38170898
DOI: 10.1039/d3dt03372d