Ultrastructural changes in giant cell tumor of bone cultured cells exposed to quercetin.

Giant cell tumor of bone (GCTB) is a primary bone tumor that affects skeletally mature people and whose main treatment is surgical. Because there are few pharmacological alternatives for the treatment of this tumor to find other molecules or compounds that could be potential therapeutic agents is desirable. Quercetin is a flavonoid with described antitumoral effect in different types of cancer cell lines that could be a possible option in GCTB treatment. However, there is no literature about the effect of quercetin on GCTB. In the present paper, we reported the ultrastructural changes in GCTB cells exposed to quercetin and also determined the expression of RIP1K, Caspase 3 and Caspase 8 on the exposed cells. For this purpose, GCTB sample was obtained from one patient and cultured. Quercetin affected all the histological components of the GCTB. The ultrastructural changes consisted mainly in necroptosis, autophagocytosis and secondary necrosis. This is the first report about quercetin effects on giant cell tumor of bone cultured cells. Further studies in other models could be done to support the use of quercetin as a complementary treatment in giant cell tumor of bone.Abbreviations: Giant cell tumor of bone (GCTB); transmission electron microscopy (TEM); reverse transcription - polymerase chain reaction (RT-PCR); receptor interacting protein kinase 1 (RIP1K); Dulbecco's Modified Eagle's Medium (DMEM).

The Role of the Density Response Kernel in the Protonation Process.

The interaction between a Lewis base and a proton produces large changes in the electron distribution of the proton-accepting species. The quantum description of the change in the electronic properties can be predicted by perturbative models. Density functional theory-based reactivity indices are useful quantities to predict the changes in the energy and the electron density of electronic systems. However, the perturbation produced by the proton, namely, the electric field of a bare nucleus, usually leads to the use of perturbative terms beyond the first order. In this work, we analyze the effect of the protonation on the electronic structure of different Lewis bases. We also identify the leading term in the perturbative expansion that determines the protonation site and try to relate it with the chemical nature of the Lewis base. Even when the interaction is initially dominated by the electrostatic forces, we found that the electron redistribution effects can play a more relevant role for highly polarizable species.

Litiasis renal en paciente con enfermedad de crohn: reporte de caso / Renal lithiasis in patient with crohn's disease: case report

Caso de litiasis renal por oxalato de calcio asociado a enfermedad de Crohn de reciente debut en paciente masculino 43 años proveniente del Canton las Piñas, Provincia El Oro en Ecuador, sin antecedentes patológicos en relación a su enfermedad. En enero 2020 acude a consulta particular con dolor en fosa iliaca derecha, fiebre, fatiga, hiporexia, pérdida de peso, tenesmo y diarrea. Gastroenterólogo observó colon derecho con úlceras, áreas de mucosa infiltrada, y el estudio anatomopatológico identifica ulceraciones en subserosa, abscesos, infiltrado inflamatorio mixto, granulomas epitelioides con células gigantes multinucleadas. Previo consentimiento se realiza ecosonografía, detectándose un cálculo renal derecho de 5 mm de tamaño y otro de 4 mm en el izquierdo. El análisis de orina reporta aciduria, cristales oxalato de calcio y la radiografía simple demostró sombra de los cálculos. El estudio metabólico la 1,25 dihidroxivitamina D y la hormona paratiroidea resultó negativo. La evolución fue favorable y continua en control periódico que de ameritar se ordenaría tomografía helicoidal sin contraste o urograma excretorio.

We present a case of kidney stones due to calcium oxalate stones associated with Crohn's disease of recent debut in a 43-year-old male patient from the Piñas canton-El Oro Province-Ecuador with no personal and family pathological history in relation to his disease and that in January 2020 he went to a private medical consultation for presenting colic-type abdominal pain located in the right iliac fossa, fever, fatigue, hyporexia, weight loss, tenesmus and sometimes diarrhea. The gastroenterologist observed: right colon with ulcers and infiltrated mucosa areas; samples are taken for histopathological study. Anatomopathology It was identified ulcerations in subserosa, abscesses, mixed inflammatory infiltrate, epithelioid granulomas with multinucleated giant cells diagnosed with Crohn's disease. With the patient's consent, an echo-sonographic study was made, detecting a right kidney stone 5 mm in size and 4 mm in the left. Urinalysis showed aciduria, calcium oxalate crystals, and plain abdominal radiography showed shadow of the stones. In the metabolic study the 1,25 dihydroxyvitamin D and parathyroid hormone was negative. The evolution was favorable and he continuous in periodic control that, if it's required, would be ordered a helical computed tomography without contrast or excretory urogram.

Reactivity of Carbon Molecular Clusters from a Hückel-Type Model.

The chemical reactivity of molecular clusters, mainly from the same atom type, is analyzed by using the Fukui function. The Fukui function at each atomic site is estimated from a Hückel-like approach, based on the variational principle for this reactivity index, where we go beyond the connectivity matrix and introduce a bond-distance dependence in the off-diagonal terms. This approach includes the full set of molecular orbitals with different weights and provides the correct reactivity pattern of the nanoparticle C360.

Comment on "Power Law Distribution Concerning Absolute Free Energies of Linear Sulfur Chains, Polythiazyls, Polyisoprenes, Linear trans-Polyenes, and Polyynes".

Recently, an analysis of some linear molecular chains showed that the molecular energy grows as a linear function of the number of fragments in molecules of the form A-Bn-C, where A, B, and C are chemical fragments. Additionally, the difference in the energy per fragment of two consecutive molecular chains was fitted into a power law form showing similar exponents close to 2. In this contribution, a natural expression, different from the power law, is presented for the previously mentioned difference.

Chemical reactivity of the frustrated Lewis pairs in borophosphines: a theoretical analysis of their Lewis acidity, Lewis basicity and Fukui function.

The chemical reactivity of a set of borophosphines of the general formula R2B-G-PY2, where G is the connector group between the Lewis acidic site, a borane group, and the Lewis basic site, a phosphine fragment, is theoretically investigated through their Lewis acidity and Lewis basicity, as well as the location of the Fukui function and the shape of the molecular electrostatic potential. The role of some global reactivity descriptors, like the vertical ionization potential, I, and the vertical electron affinity, A, is also analyzed in order to gain a deeper insight on the intrinsic chemical reactivity of these borophosphines. We also use the energies involved in the formation of the adducts between the borophosphine and the ions H- and H+ to estimate the Lewis acidity and Lewis basicity, respectively; by their nature, these energies represent local reactivity descriptors. Some of these borophosphines are able to activate the covalent bond in the hydrogen molecule. Possible paths for the hydrogen release reaction from the zwitterion R[Formula: see text]HB-G-PH[Formula: see text] are studied using the mentioned quantities, suggesting that an intramolecular hydride shift mechanism seems to be more favorable than a proton migration process. The acceptor Fukui function f+(r) proved to be useful to identify the acidic molecular sites for the interaction with the hydride ion and the relative stability of the corresponding adducts is related to the relative values of this function.

Stability of the different AlOOH phases under pressure.

The pressure effects on three different AlOOH structures (α, γ, and δ phases) are systematically analyzed by density functional theory with different exchange and correlation energy functional approximations, namely two local, two generalized-gradient approximation (GGA), and two GGA for solids (GGAsol). Phase stability, compressibility and hydrogen bond evolution are studied in a range of pressures from 0 to 30 GPa. In general, the use of GGAsol functionals is mandatory in order to have the correct phase stability order, a good description of the hydrogen bonds, and a close agreement with the experimental lattice parameters at the various pressures. Pressure-induced hydrogen-bond symmetrization is found in γ and δ phases at high compression, while the hydrogen bonds in the α phase remain asymmetric. A detailed analysis of the uncertainties on the values of the bulk moduli and their pressure derivative at zero pressure deduced by fitting calculated or experimental (P,V) data is also presented.

Bond Fukui indices: comparison of frozen molecular orbital and finite differences through Mulliken populations.

Bond Fukui functions and matrices are introduced for ab initio levels of theory using a Mulliken atoms in molecules model. It is shown how these indices may be obtained from first-order density matrix derivatives without need for going to second-order density matrices as in a previous work. The importance of taking into account the nonorthogonality of the basis in ab initio calculations is shown, contrasting the present results with previous work based on Hückel theory. It is shown how the extension of Fukui functions to Fukui matrices allows getting more insight into the nature of bond Fukui functions. All presently introduced indices respect the necessary normalization conditions and include the classical single atom condensed Fukui functions.

Reactivity indicators for degenerate states in the density-functional theoretic chemical reactivity theory.

Density-functional-theory-based chemical reactivity indicators are formulated for degenerate and near-degenerate ground states. For degenerate states, the functional derivatives of the energy with respect to the external potential do not exist, and must be replaced by the weaker concept of functional variation. The resultant reactivity indicators depend on the specific perturbation. Because it is sometimes impractical to compute reactivity indicators for a specific perturbation, we consider two special cases: point-charge perturbations and Dirac delta function perturbations. The Dirac delta function perturbations provide upper bounds on the chemical reactivity. Reactivity indicators using the common used "average of degenerate states approximation" for degenerate states provide a lower bound on the chemical reactivity. Unfortunately, this lower bound is often extremely weak. Approximate formulas for the reactivity indicators within the frontier-molecular-orbital approximation and special cases (two or three degenerate spatial orbitals) are presented in the supplementary material. One remarkable feature that arises in the frontier molecular orbital approximation, and presumably also in the exact theory, is that removing electrons sometimes causes the electron density to increase at the location of a negative (attractive) Dirac delta function perturbation. That is, the energetic response to a reduction in the external potential can increase even when the number of electrons decreases.

Electrodonating and electroaccepting powers.

By introducing an electron bath that represents the chemical environment in which a chemical species is immersed, and by making use of the second-order Taylor series expansions of the energy as a function of the number of electrons in the intervals between N - 1 and N, and N and N + 1, we show that the electrodonating (omega-) and the electroaccepting (omega+) powers may be defined as omega-/+ = (mu-/+)2/2eta-/+, where mu-/+ are the chemical potentials and eta-/+ are the chemical hardnesses, in their corresponding intervals. Approximate expressions for omega- and omega+ in terms of the ionization potential I and the electron affinity A are established by assuming that eta- = eta+ = eta = mu+ - mu-. The functions omega-/+(r) = omega-/+f -/+(r), where f -/+(r) are the directional Fukui functions, derived from a functional Taylor series for the energy functional truncated at second order, represent the local electrodonating and electroaccepting powers.

Molecular fragments in density functional theory.

The second-order density functional approach to the partitioning of the molecular density of Cedillo, Chattaraj, and Parr (Int. J. Quantum Chem. 2000, 77, 403-407) is used, together with a local assumption for the function that projects the total density into its components, to show that the distribution function adopts a stockholders form, in terms of the local softness of the isolated fragments, and that the molecular Fukui function is distributed in the molecular fragments in the same proportion as the electronic density.

Koopmans-like approximation in the Kohn-Sham method and the impact of the frozen core approximation on the computation of the reactivity parameters of the density functional theory.

A Koopmans-like approximation is introduced in the spin-polarized version of the Kohn-Sham (KS) density functional theory to obtain a relation between KS orbital energies and vertical ionization potential and electron affinity. Expressions for reactivity indexes (like electronegativity, hardness, electrophilicity, and excitation energies) include KS frontier orbital energies and additional contributions associated with the self-interaction correction. Those reactivity parameters were computed with different exchange-correlation functionals to test the approach for a set of small molecules. The results show that the present approximation provides a better way to estimate hardness, electronegativity, and electrophilicity than just the use of frontier orbital energy values. However KS HOMO and LUMO energy gap gives a better agreement with excitation energies.