Involvement of Ca2+ Signaling in the Synergistic Effects between Muscarinic Receptor Antagonists and β2-Adrenoceptor Agonists in Airway Smooth Muscle

Long-acting muscarinic antagonists (LAMAs) and short-acting β₂-adrenoceptor agonists (SABAs) play important roles in remedy for COPD. To propel a translational research for development of bronchodilator therapy, synergistic effects between SABAs with LAMAs were examined focused on Ca²⁺ signaling using simultaneous records of isometric tension and F340/F380 in fura-2-loaded tracheal smooth muscle. Glycopyrronium (3 nM), a LAMA, modestly reduced methacholine (1 μM)-induced contraction. When procaterol, salbutamol and SABAs were applied in the presence of glycopyrronium, relaxant effects of these SABAs are markedly enhanced, and percent inhibition of tension was much greater than the sum of those for each agent and those expected from the BI theory. In contrast, percent inhibition of F340/F380 was not greater than those values. Bisindolylmaleimide, an inhibitor of protein kinase C (PKC), significantly increased the relaxant effect of LAMA without reducing F340/F380. Iberiotoxin, an inhibitor of large-conductance Ca²⁺-activated K⁺ (K_Ca) channels, significantly suppressed the effects of these combined agents with reducing F340/F380. In conclusion, combination of SABAs with LAMAs synergistically enhances inhibition of muscarinic contraction via decreasing both Ca²⁺ sensitization mediated by PKC and Ca²⁺ dynamics mediated by K_Ca channels. PKC and K_Ca channels may be molecular targets for cross talk between β₂-adrenoceptors and muscarinic receptors.     

Effect of Thyrotropin on Osteopontin,Integrin αvβ3, and VCAM-1 in the Endothelium via Activation of Akt

Numerous epidemiological studies have shown that subclinical hypothyroidism (SCH) can impair endothelial function and cause dyslipidemia. Studies have evaluated the effects of thyroid stimulating hormone (TSH) on endothelial cells, but the mechanism underlying the proatherosclerotic effect of increased TSH levels remains unclear. In the present study, SCH rat models were established in thyroidectomized Wistar rats that were given l-T₄ daily. The results showed that in vivo, the expression of osteopontin (OPN) vascular cell adhesion molecule (VCAM-1), and levels of integrin α_vβ₃ in the aortic tissue in SCH and Hypothyroidism (CH) groups was higher than in the control group. However, the effect in the SCH group was higher than in the CH group. In vitro, results showed that different concentration and time gradients of TSH stimulation could increase the expression of OPN, VCAM-1, and integrin α_vβ₃, and this was accompanied by extracellular signal regulated kinase 1/2 (Erk1/2) and Akt activation in human umbilical vein endothelial cells (HUVECs). TSH induced elevation of these proatherosclerotic factors was partially suppressed by a specific Akt inhibitor but not by a specific Erk inhibitor. Findings suggested that the endothelial dysfunction caused by SCH was related to increased proatherosclerotic factors induced by TSH via Akt activation.     

Study on the Expression and Clinical Significances of Lewis y Antigen and Integrin αv, β3 in Epithelial Ovarian Tumors

Objective

To detect the expression and clinical significances of Lewis y antigen and integrin αv, β3 in epithelial ovarian tumors, and to explore the expression correlation between Lewis y antigen and integrin αv, β3.

Methods

Immunohistochemical staining was performed in 95 cases of epithelial ovarian cancer, 37 cases of borderline tumors, 20 cases of benign tumors, and 20 cases of normal ovarian tissue, for the detection of Lewis y antigen and integrin αv, β3 expressions, and to analyze the relationship between Lewis y antigen and integrin, and the relationship between clinical and pathological parameters of ovarian cancer. In addition, immunofluorescence double labeling was utilized to detect the expression correlation between Lewis y antigen and integrin αv, β3 in ovarian cancer.

Results

In epithelial ovarian tumors, the expression rate of Lewis y antigen was 81.05%, significantly higher than that of borderline (51.53%) (P < 0.05) and benign (25%) (P < 0.01) tumors, and normal ovarian tissues (0) (P < 0.01). The expression rate of integrin αv, β3 in malignant epithelial ovarian tumors was 78.95% and 82.11%, respectively, significantly higher than that of the borderline (45.94%, 40.54%) (both P < 0.05), benign group (10.00%, 15.00%) (both P < 0.01) and normal ovary group (5%, 15%) (both P < 0.01).

Conclusions

Lewis y and integrins αv, β3 are relevant to pelvic and abdominal diffusion and metastasis of ovarian cancer cells, suggesting that these two molecules mediate a boosting function for tumor metastasis.     

Immuno-Expression of Endoglin and Smooth Muscle Actin in the Vessels of Brain Metastases. Is There a Rational for Anti-Angiogenic Therapy?

Despite ongoing clinical trials, the efficacy of anti-angiogenic drugs for the treatment of brain metastases (BM) is still questionable. The lower response rate to anti-angiogenic therapy in the presence of BM than in metastatic disease involving other sites suggests that BM may be insensitive to these drugs, although the biological reasons underlining this phenomenon are still to be clarified. With the aim of assessing whether the targets of anti-angiogenic therapies are actually present in BM, in the present study, we analyzed the microvessel density (MVD), a measure of neo-angiogenesis, and the vascular phenotype (mature vs. immature) in the tumor tissue of a series of BM derived from different primary tumors. By using immunohistochemistry against endoglin, a specific marker for newly formed vessels, we found that neo-angiogenesis widely varies in BM depending on the site of the primary tumor, as well as on its histotype. According to our results, BM from lung cancer displayed the highest MVD counts, while those from renal carcinoma had the lowest. Then, among BM from lung cancer, those from large cell and adenocarcinoma histotypes had significantly higher MVD counts than those originating from squamous cell carcinoma (p = 0.0043; p = 0.0063). Of note, MVD counts were inversely correlated with the maturation index of the endoglin-stained vessels, reflected by the coverage of smooth muscle actin (SMA) positive pericytes (r = −0.693; p < 0.0001). Accordingly, all the endoglin-positive vessels in BM from pulmonary squamous cell carcinoma and renal carcinoma, displayed a mature phenotype, while vessels with an immature phenotype were found in highly vascularized BM from pulmonary large cell and adenocarcinoma. The low MVD and mature phenotype observed in BM from some primary tumors may account for their low sensitivity to anti-angiogenic therapies. Although our findings need to be validated in correlative studies with a clinical response, this should be taken into account in therapeutic protocols in order to avoid the adverse effects of useless therapies.     

Na(+), K(+)-ATPase Subunit Composition in a Human Chondrocyte Cell Line; Evidence for the Presence of α1, α3, β1, β2 and β3 Isoforms

Membrane transport systems participate in fundamental activities such as cell cycle control, proliferation, survival, volume regulation, pH maintenance and regulation of extracellular matrix synthesis. Multiple isoforms of Na(+), K(+)-ATPase are expressed in primary chondrocytes. Some of these isoforms have previously been reported to be expressed exclusively in electrically excitable cells (i.e., cardiomyocytes and neurons). Studying the distribution of Na(+), K(+)-ATPase isoforms in chondrocytes makes it possible to document the diversity of isozyme pairing and to clarify issues concerning Na(+), K(+)-ATPase isoform abundance and the physiological relevance of their expression. In this study, we investigated the expression of Na(+), K(+)-ATPase in a human chondrocyte cell line (C-20/A4) using a combination of immunological and biochemical techniques. A panel of well-characterized antibodies revealed abundant expression of the α1, β1 and β2 isoforms. Western blot analysis of plasma membranes confirmed the above findings. Na(+), K(+)-ATPase consists of multiple isozyme variants that endow chondrocytes with additional homeostatic control capabilities. In terms of Na(+), K(+)-ATPase expression, the C-20/A4 cell line is phenotypically similar to primary and in situ chondrocytes. However, unlike freshly isolated chondrocytes, C-20/A4 cells are an easily accessible and convenient in vitro model for the study of Na(+), K(+)-ATPase expression and regulation in chondrocytes.     

Low temperature heat capacity measurements of β-Si3N4 and γ-Si3N4: Determination of the equilibrium phase boundary between β-Si3N4 and γ-Si3N4

Isobaric heat capacities of β-Si₃N₄ and γ-Si₃N₄ were measured at temperatures between 1.8 and 309.9 K with a thermal relaxation method. The measured heat capacities of γ-Si₃N₄ are smaller than those of β-Si₃N₄ in this temperature range. Using these data, we determined the standard entropies of β-Si₃N₄ and γ-Si₃N₄ to be 62.30 J·mol⁻¹ K⁻¹ and 51.79 J·mol⁻¹ K⁻¹, respectively. The equilibrium phase boundary between β-Si₃N₄ and γ-Si₃N₄ was calculated using these values and thermodynamic parameters reported in previous studies. The obtained equilibrium phase transition pressure at 2000 K is 11.4 GPa. It is lower than the experimental pressures at which γ-Si₃N₄ was synthesized in previous studies. The calculated Clapeyron slope at this temperature is 0.6 MPa K⁻¹, which is consistent with those of theoretical studies.     

Studying the mechanism of the interaction between silicon nitride, oxygen, and nitrogen in heating and the processes of defect formation in Si3N4 — gas systems

The method of precision thermal massometry is used to study the interaction between silicon nitride, oxygen, and nitrogen in nonisothermal heating at 300 -1300 K and a partial gas pressure of 19,998.3 Pa (150 Torr). The behavior of Si₃N₄ heated in forevacuum is studied. A special computer analysis of the experimentally obtained dependencies has provided kinetic equations for analyzing and determining the mechanisms of these processes and computing their activation energy. The experimental data are used for creating a hypothesis that the nitrogen sublattice of Si₃N₄ is dispersed before the beginning of its interaction with oxygen and nitrogen.     

Determining the cause-and-effect relationships responsible for coal properties. 3. Association of chemical elements and role of indicators and accompanying elements in assessing the variability of beds’ mineral composition

In the development of productive coal and oil beds, certain geochemical conditions facilitate the formation of elementary associations that include indicator elements and accompanying elements. The determination of those associations permits the identification of the features of mineral formation in the beds and the processes that affect the variability of the mineral composition in the intervening rock.     

First-principles simulation of the growth of in situ synthesised β-Sialon and its effects on the thermo-mechanical properties of Al2O3-C refractory composites

Columnar β-Sialon bonding phases were in situ synthesised in Al₂O₃-C refractory composites and their growth mechanism was simulated based on first-principles calculations. The experimental results indicated that the addition of Fe₂O₃ as a catalyst accelerated the transformation of Si₃N₄ to β-Sialon, resulting in a well-developed columnar structure. The (100) facet was the primary surface for crystal growth during the transformation process of Si₃N₄ into β-Sialon. According to first-principles calculations, the surface energy of the (100) facet decreased greatly due to the substitution of (Si, N) pairs with (Al, O). The catalyst could promote the adsorption of gaseous phases on the (100) facet of Si₃N₄ and decreased the gas adsorption energy of both SiO and Al₂O. Owing to the presence of in situ synthesised columnar β-Sialon bonding phases, the residual crushing strength of Al₂O₃-C refractory composites after 5 thermal shock cycles increased by 25.1%.     

Diastereotopic relationship between planar and central chiralities in the formation of Ru(η3-allyl)(CO)(PPh3)(L–L′) complexes

Hydride ruthenium complexes, RuHCl(CO)(PPh₃)₂(L–L^′) 3 (L–L^′=bidentate ligand having nitrogen and oxygen) react with allenes to give Ru(η³-allyl)(CO)(PPh₃)(L–L^′) complexes 5 in good yields via hydrometalation reaction. The complexes 5 have planar chirality at the η³-allyl ligand and central chirality at the Ru metal, and consist of one pair of enantiomers. Ligand substitution reaction of Ru(η³-allyl)Cl(CO)(PPh₃)₂ complexes 6 with bidentate ligands (L–L^′) also afford the complexes 5 which have the same stereochemistry as those formed by the hydrometalation reaction. The planar chirality is controlled by the central chirality at the Ru metal in both the formations of the complexes 5. The structure of 5a (L–L^′=N–N bidentate ligand) was determined by the X-ray crystal structure analysis.     

Phase and melting relationships of β, α and α′-Ca3(PO4)2 polymorphs in the Ca3(PO4)2-Zn3(PO4)2 system

In order to provide an exact knowledge of the phase transitions and melting relationships of Ca₃(PO₄)₂ (TCP) in the presence of zinc, a revisited version of the rich-Ca₃(PO₄)₂ region of the phase diagram of the system Ca₃(PO₄)₂-Zn₃(PO₄)₂ has been established in the present work. Experimental determination of this diagram was carried out by solid-state reactions of samples prepared from pure NH₄H₂PO₄, CaCO₃ and ZnO raw materials. X-ray Diffraction, Differential Thermal Analyses and Field Emission Scanning Electron Microscopy studies allowed to revise the α, β, α + β-TCP phase stability fields, delimitating for the first time the biphasic α + α′-TCP field and the melting relationships in the high temperature region of the system. The results allowed to determine two peritectic invariant points, at ≈1400 °C for 95 mol% Ca₃(PO₄)₂ and at ≈1490 °C for ≈99.5 mol% Ca₃(PO₄)₂.     

Relationship between the Bond Valence and the Temperature Coefficient of the Resonant Frequency in the Complex Perovskite (Pb1−xCax)[Fe0.5(Nb1−yTay)0.5]O3

The temperature coefficient of the resonant frequency (TCF) of complex perovskite (Pb_1−xCa_x)[Fe_0.5(Nb_1−yTa_y)_0.5]O₃ ceramics (x= 0.5, 0.55; 0.0 ≤y≤ 1.0) was investigated, relative to the bond valence of the A- and B-site ions in the ABO₃ perovskite structure (such as the barium-, strontium-, and calcium-based complex perovskites). The TCF of these complex perovskite compounds varied with the bond valence of the A- and B-sites and the tolerance factor (t) in the perovskite structure. In the tilted region (t < 1.0), the tilting of the oxygen octahedra increased and the TCF decreased, because of the increased bond valence of the B-site. Also, the dependence of TCF on the bond valence of the A-site was similar to its dependence on t.     

Phylogenetic-Derived Insights into the Evolution of Sialylation in Eukaryotes: Comprehensive Analysis of Vertebrate β-Galactoside α2,3/6-Sialyltransferases (ST3Gal and ST6Gal)

Cell surface of eukaryotic cells is covered with a wide variety of sialylated molecules involved in diverse biological processes and taking part in cell–cell interactions. Although the physiological relevance of these sialylated glycoconjugates in vertebrates begins to be deciphered, the origin and evolution of the genetic machinery implicated in their biosynthetic pathway are poorly understood. Among the variety of actors involved in the sialylation machinery, sialyltransferases are key enzymes for the biosynthesis of sialylated molecules. This review focus on β-galactoside α2,3/6-sialyltransferases belonging to the ST3Gal and ST6Gal families. We propose here an outline of the evolutionary history of these two major ST families. Comparative genomics, molecular phylogeny and structural bioinformatics provided insights into the functional innovations in sialic acid metabolism and enabled to explore how ST-gene function evolved in vertebrates.