Search results for "Polyp"
showing 10 items of 1415 documents
Endoscopic Microsurgery of Rectal Tumors
1987
Seventy-five patients with sessile adenomas or early carcinomas of the rectum or rectosigmoid were operated on with the new technique "transanal endoscopic microsurgery" Employing a newly developed complex endoscopic operating system, complete removal of sessile adenomas can be accomplished up to a distance of 25 cm from the anal verge, accurately and non-invasively. Complications occurred in three cases, with no resulting mortality. In the follow-up period we discovered only one adenomatous recurrence that required operative treatment. The superior accuracy of preparation, a short average stay in hospital, and low recurrence and complication rates are the advantages of this transanal endos…
Expression profile of components of the β-catenin destruction complex in oral dysplasia and oral cancer
2021
Background Oral cancer represents the sixth most common cancer in the world and is associated with 40-50% survival at 5 years. Within oral malignancies, oral squamous cell carcinoma (OSCC) is commonly preceded by potentially malignant lesions, which, according to histopathological criteria, are referred to as oral dysplasia and their diagnosis are associated with higher rates of malignant transformation towards cancer. We recently reported that aberrant activation of the Wnt/β‑catenin pathway is due to overexpression of Wnt ligands in oral dysplasia. However, the expression of other regulators of this pathway, namely components of the β-catenin destruction complex has not been explored in o…
The inorganic polymer, polyphosphate, blocks binding of SARS-CoV-2 spike protein to ACE2 receptor at physiological concentrations
2020
Graphical abstract The inorganic physiological polymer, polyphosphate, blocks binding of SARS-CoV-2 spike protein to ACE2 receptor at physiological concentrations. This discovery proposes polyphosphate as a new member of the host's antiviral innate immune defense.
Copper(II)-Induced Restructuring of ZnuD, a Zinc(II) Transporter from Neisseria meningitidis.
2019
Cluster 2 (288HDDDNAHAHTH298) from Neisseria meningitidis ZnuD is a flexible loop that captures zinc(II) ions, acting as a "fishing net". We describe its Zn(II) and Cu(II) binding capabilities, focusing on the thermodynamics of such interactions and comparing them with the complexes of the 1MAHHHHHHL9-NH2 region. Copper(II) complexes with the studied ZnuD regions are thermodynamically more stable than the zinc(II) ones-Cu(II) complexes dominate in solution even in close to physiological ratios of the studied metal ions (a 10-fold excess of Zn(II) over Cu(II)). While the binding of native Zn(II) has no significant impact on the structure of its transporter, Cu(II) binding induces a conformat…
New concepts in multidentate ligand chemistry: effects of multidentarity on catalytic and spectroscopic properties of ferrocenyl polyphosphines.
2008
This tutorial review devoted to ligand chemistry deals with the design and properties of ferrocenyl polyphosphines, an original class of multidentate ligands. The development of a varied library of ferrocenyl tetra-, tri- and diphosphine ligands is reviewed. The multidentate nature of these species has led to unique spectroscopic and catalytic properties, in which the spatial proximity of phosphorus atoms is crucial. Regarding their catalytic applications, the key issues of catalyst longevity and ultralow catalyst loadings are discussed. Another part is concerned with fundamental advances gained in physical chemistry for structure elucidation by the study of the intriguing “through-space” N…
Diversity of Omega Glutathione Transferases in mushroom-forming fungi revealed by phylogenetic, transcriptomic, biochemical and structural approaches
2021
International audience; The Omega class of glutathione transferases (GSTs) forms a distinct class within the cytosolic GST superfamily because most of them possess a catalytic cysteine residue. The human GST Omega 1 isoform was first characterized twenty years ago, but it took years of work to clarify the roles of the human isoforms. Concerning the kingdom of fungi, little is known about the cellular functions of Omega glutathione transferases (GSTOs), although they are widely represented in some of these organisms. In this study, we re-assess the phylogeny and the classification of GSTOs based on 240 genomes of mushroom-forming fungi (Agaricomycetes). We observe that the number of GSTOs is…
Triphenylphosphane Pt(II) complexes containing biologically active natural polyphenols: Synthesis, crystal structure, molecular modeling and cytotoxi…
2016
Platinum complexes bearing phosphane ligands in cis configuration with deprotonated flavonoids (3-hydroxyflavone, quercetin) and deprotonated ethyl gallate were synthesized starting from cis-[PtCl2(PPh3)(2)]. In all cases, O,O' chelate structures were obtained. While quercetin and ethyl gallate complexes are quite stable in solution, the 3-hydroxyflavonate complex undergoes a slow aerobic photodegradation in solution with formation of salicylic and benzoic acids. The X-ray diffraction structures of quercetin and ethyl gallate complexes are reported. Cell cycle studies (in the dark) of the complexes in two human cell lines revealed that the cytotoxic activity of the complex bearing 3-hydroxy…
Stepwise sequential redox potential modulation possible on a single platform.
2011
Step by step: The cluster [3,3'-Co(1,2-C(2)B(9)H(11))(2)](-) is an excellent platform for making a stepwise tunable redox potential system by dehydroiodination. With the addition of up to eight iodine substituents (purple; see picture), there is a fall in the E(1/2)(Co(III)/Co(II)) value from -1.80 V to -0.68 V (vs. Fc(+)/Fc; Fc = ferrocene). A practical application of this tunability has been observed in the growth of polypyrrole.
Concentration dependent effects of commonly used pesticides on activation versus inhibition of the quince (Cydonia Oblonga) polyphenol oxidase
2009
Polyphenol oxidase (PPO) catalyzes the oxidation of o-diphenols to their respective quinones which undergo autopolymerization and form dark pigments. The interaction of PPO with various substrates and effectors remains the focus of intensive investigations due to the enzyme's key role in pigments biosynthesis including animal melanogenesis and fruit/fungi enzymatic browning. In this study, the effect of a range of commonly used pesticides on the enzyme activity has been evaluated using the purified quince (Cydonia oblonga Miller) PPO. The biochemical analysis showed that, in the presence of high pesticide concentrations, the enzyme was competitively inhibited, particularly with benomyl, car…
Mona/Gads SH3C binding to hematopoietic progenitor kinase 1 (HPK1) combines an atypical SH3 binding motif, R/KXXK, with a classical PXXP motif embedd…
2004
Hematopoietic progenitor kinase 1 (HPK1) is implicated in signaling downstream of the T cell receptor. Its non-catalytic, C-terminal half contains several prolinerich motifs, which have been shown to interact with different SH3 domain-containing adaptor proteins in vitro. One of these, Mona/Gads, was also shown to bind HPK1 in mouse T cells in vivo. The region of HPK1 that binds to the Mona/Gads C-terminal SH3 domain has been mapped and shows only very limited similarity to a recently identified high affinity binding motif in SLP-76, another T-cell adaptor. Using isothermal titration calorimetry and x-ray crystallography, the binding of the HPK1 motif to Mona/Gads SH3C has now been characte…