Single and double reduction of C\u3csub\u3e60\u3c/sub\u3e in 2:1 γ-cyclodextrin/[60]fullerene inclusion complexes by cyclodextrin radicals

Spectroscopic and chemical properties of γ-CD• radicals, resulting from the abstraction by HO• radicals of hydrogen atoms, have been investigated using pulse radiolysis. The reactions of γ-CD• radicals with C60 in 2:1 γ-CD/C60 inclusion complexes have been studied in aqueous solutions. It has been demonstrated that the γ-CD_ radicals are reducing species producing C60•— monoanion radicals, as well as doubly reduced C602— , well characterized by their absorption spectra in the near IR. The oxidation potential of γ-CD• radical is estimated to be more negative than –390 mV vs. NHE. The kinetics of the C60 reduction by γ-CD• radicals have been determined and compared with kinetics by other reducing species including the solvated electron (e—aq) and CO2•— radicals. It was observed that the method of preparation of the 2:1 γ-CD/C60 inclusion complexes modifies the C60 reduction mechanism

Discordance in pathology report after central pathology review: Implications for breast cancer adjuvant treatment

Abstract Aim Pathological predictive factors are the most important markers when selecting early breast cancer adjuvant therapy. In randomized clinical trials the variability in pathology report after central pathology review is noteworthy. We evaluated the discordance rate (DR) and inter-rater agreement between local and central histopathological report and the clinical implication on treatment decision. Methods A retrospective analysis was conducted in a series of consecutive early breast cancer tumors diagnosed by local pathologists and subsequently reviewed at the Pathology Division of European Institute of Oncology. The inter-rater agreement (k) between local and central pathology was calculated for Ki-67, grading, hormone receptors (ER/PgR) and HER2/neu. The Bland–Altman plots were derived to determine discrepancies in Ki-67, ER and PgR. DR was calculated for ER/PgR and HER2. Results From 2007 to 2013, 187 pathology specimens from 10 Cancer Centers were reviewed. Substantial agreement was observed for ER (k0.612; 95% CI, 0538–0.686), PgR (k0.659; 95% CI, 0580–0.737), Ki-67 (k0.609; 95% CI, 0.534–0.684) and grading (k0.669; 95% CI, 0.569–0.769). Moderate agreement was found for HER2 (k0.546; 95% CI, 0444–0.649). DR was 9.5% (negativity to positivity) and 31.7% (positivity to negativity) for HER2 and 26.2% (negativity to positivity) and 12.5% (positivity to negativity) for ER/PgR. According to changes in Her2 and ER/PgR status, 23 (12.2%) and 33 (17.6%) systemic prescription were respectively modified. Conclusions In our retrospective analysis, central pathological review has a significant impact in the decision-making process in early breast cancer, as shown in clinical trials. Further studies are warranted to confirm these provocative results

Contractile efficiency of dystrophic mdx mouse muscle: In vivo and ex vivo assessment of adaptation to exercise of functional end points

Progressive weakness is a typical feature of Duchenne muscular dystrophy (DMD) patients and is exacerbated in the benign mdx mouse model by in vivo treadmill exercise. We hypothesized a different threshold for functional adaptation of mdx muscles in response to the duration of the exercise protocol. In vivo weakness was confirmed by grip strength after 4, 8 and 12 weeks of exercise in mdx mice. Torque measurements revealed that exercise-related weakness in mdx mice correlated with the duration of the protocol, while wild-type (wt) mice were stronger. Twitch and tetanic forces of isolated diaphragm and extensor digitorum longus (EDL) muscles, were lower in mdx compared to wt mice. In mdx, both muscle types exhibited greater weakness after a single exercise bout, but only in EDL after a long exercise protocol. As opposite to wt muscles, mdx EDL ones did not show any exercise-induced adaptations against eccentric contraction force drop. qRT-PCR analysis confirmed the maladaptation of genes involved in metabolic and structural remodeling, while damage-related genes remained significantly upregulated and angiogenesis impaired. Phosphorylated AMP kinase level increased only in exercised wt muscle. The severe histopathology and the high levels of muscular TGF-β1 and of plasma matrix metalloproteinase-9 confirmed the persistence of muscle damage in mdx mice. Then, dystrophic muscles showed a partial degree of functional adaptation to chronic exercise, although not sufficient to overcome weakness nor signs of damage. The improved understanding of the complex mechanisms underlying maladaptation of dystrophic muscle paves the way to a better managment of DMD patients

Local allergic rhinitis: entopy or spontaneous response?

Background The existence of a local allergic rhintis was proposed on the basis of the detection of nasal IgE in the absence of a systemic sensitization. Nevertheless, the significance of this phenomenon remains still unclear.We assessed the presence of mucosal nasal IgE in patients with ascertained allergic rhinitis, nonallergic rhinitis with inflammation and in healthy controls.Methods Consecutive patients with a well ascertained diagnosis (clinical history, skin prick test, specific IgE assay, nasal endoscopy, nasal cytology) underwent an immunoenzymatic measurement of specific IgE to grass, cypress, parietaria and olive in nasal scrapings.Results Fifteen patients with allergic rhinitis, 12 with non allergic rhinitis and 14 healthy subjects were studied. The patients with allergic and nonallergic rhinitis had higher nasal symptoms as compared to control subjects. Systemic sensitizatition (assessed by skin test and CAP-RAST) was obviously more frequent in allergic rhinitis, than in the other two groups. Allergen-specific nasal IgE could be detected in all groups (86,7, 33,3, and 50 % positive, respectively), even more frequently in the control group than in nonallergic rhinitis patients. No difference among allergens was identified. Out of the 26 non-allergic patients (non allergic rhinitis + controls) nasal IgE were positive in 11(42 %).Discussion According to the results, the presence of nasal IgE against allergens seems to be a non-specific phenomenon, since they can be detected also in non allergic rhinitis and in healthy subjects.Conclusion It can be hypothesized that the nasal IgE production represents a form of spontaneous immune response. Keywords: Allergic rhinitis, Nonallergic rhinitis, Sensitization, Nasal IgE, Local allergic rhinitis, Entop

Photoreduction of the ferredoxin/ferredoxin-NADP(+)-reductase complex by a linked ruthenium polypyridyl chromophore.

International audiencePhotosynthetic ferredoxin and its main partner ferredoxin-NADP(+)-reductase (FNR) are key proteins during the photoproduction of reductive power involved in photosynthetic growth. In this work, we used covalent attachment of ruthenium derivatives to different cysteine mutants of ferredoxin to trigger by laser-flash excitation both ferredoxin reduction and subsequent electron transfer from reduced ferredoxin to FNR. Rates and yields of reduction of the ferredoxin [2Fe-2S] cluster by reductively quenched Ru* could be measured for the first time for such a low redox potential protein whereas ferredoxin-FNR electron transfer was characterized in detail for one particular Ru-ferredoxin covalent adduct. For this adduct, the efficiency of FNR single reduction by reduced ferredoxin was close to 100% under both first-order and diffusion-limited second-order conditions. Interprotein intracomplex electron transfer was measured unambiguously for the first time with a fast rate of c. 6500s(-1). Our measurements point out that Ru photosensitizing is a powerful approach to study the functional interactions of ferredoxin with its numerous partners besides FNR

Enhanced Photoinduced Electron Transfer Through a Tyrosine Relay in a De Novo Designed Protein Scaffold Bearing a Photoredox Unit and a FeIIS4 Site

Electron transfer (ET) processes in biology over long distances often proceed via a series of hops, which reduces the distance dependence of the rate of ET. The protein matrix itself can be involved in mediating ET directly through the participation of redox‐active amino acids. We have designed an electron transfer chain incorporated into a de novo protein scaffold, which is capable of photoinduced intramolecular electron transfer between a photoredox unit and a FeIIS4 site through a tyrosine amino acid relay. The kinetics were characterized by nanosecond laser pulse photolysis and revealed that electron transfer from [RuIIIbpymal]3+ proceeds most efficiently via a tyrosine located ∼16 Å from Rubpymal (bpymal=1‐((1‐([2,2′‐bipyridin]‐4‐yl)‐1H‐1,2,3‐triazol‐4‐yl)methyl)‐1H‐pyrrole‐2,5‐dione). Removal of the tyrosine as the electron relay station results in a 20‐fold decrease in the apparent rate constant for the electron transfer.Sharing is caring: We have designed an electron transfer chain incorporated into a de novo protein scaffold, which is capable of photoinduced intramolecular electron transfer between a photoredox unit and a FeIIS4 site through a tyrosine amino acid relay. The kinetics were characterized by nanosecond laser pulse photolysis and revealed that electron transfer from the photoredox unit [RuIIIbpymal]3+ proceeds most efficiently via a tyrosine located circa 16 Å from Rubpymal ((bpymal=1‐((1‐([2,2′‐bipyridin]‐4‐yl)‐1H‐1,2,3‐triazol‐4‐yl)methyl)‐1H‐pyrrole‐2,5‐dione)). Removal of the tyrosine as the electron relay station results in a 20‐fold decrease in the apparent rate constant for the electron transfer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/168507/1/cptc202100014.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168507/2/cptc202100014-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168507/3/cptc202100014_am.pd

Electron transfer activity of a de novo designed copper center in a three-helix bundle fold.

International audienceIn this work, we characterized the intermolecular electron transfer (ET) properties of a de novo designed metallopeptide using laser-flash photolysis. α3D-CH3 is three helix bundle peptide that was designed to contain a copper ET site that is found in the β-barrel fold of native cupredoxins. The ET activity of Cuα3D-CH3 was determined using five different photosensitizers. By exhibiting a complete depletion of the photo-oxidant and the successive formation of a Cu(II) species at 400 nm, the transient and generated spectra demonstrated an ET transfer reaction between the photo-oxidant and Cu(I)α3D-CH3. This observation illustrated our success in integrating an ET center within a de novo designed scaffold. From the kinetic traces at 400 nm, first-order and bimolecular rate constants of 10(5) s(-1) and 10(8) M(-1) s(-1) were derived. Moreover, a Marcus equation analysis on the rate versus driving force study produced a reorganization energy of 1.1 eV, demonstrating that the helical fold of α3D requires further structural optimization to efficiently perform ET. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson