Experimental validation of specificity of the squamous cell carcinoma antigen-immunoglobulin M (SCCA-IgM) assay in patients with cirrhosis.

BACKGROUND: Squamous cell carcinoma antigen-immunoglobulin M (SCCA-IgM) is a useful biomarker for the risk of development of hepatocellular carcinoma (HCC) in patients with cirrhosis due to its progressive increase associated to HCC evolution. In patients with cirrhosis, other assays have been affected by interfering reactivities of IgM. In this study, the analytical specificity of the SCCA-IgM assay was assessed by evaluating SCCA-IgM measurement dependence on different capture phases, and by measuring the recovery of SCCA-IgM reactivity following serum fractionation. METHODS: Serum samples from 82 patients with cirrhosis were analyzed. SCCA-IgM was measured using the reference test (Hepa-IC, Xeptagen, Italy) that is based on rabbit oligoclonal anti-squamous cell carcinoma antigen (SCCA) and a dedicated ELISA with a mouse monoclonal anti-SCCA as the capture antibody. RESULTS: SCCA-IgM concentrations measured with the reference assay (median value=87 AU/mL) were higher than those measured with the mouse monoclonal test (median value=78 AU/mL). However, the differences in the SCCA-IgM distribution were not statistically significant (p>0.05). When SCCA-IgM concentrations measured with both tests were compared, a linear correlation was found (r=0.77, p<0.05). Fractionation of the most reactive sera by gel-filtration chromatography showed that total recovery of SCCA-IgM reactivity was seen only in the fractions corresponding to components with a molecular weight higher than IgM and SCCA (>2000 kDa) with both tests. CONCLUSIONS: The equivalence of both SCCA-IgM assays and the absence of reactivity not related to immune complexes support the analytical specificity of SCCA-IgM measurements. The results validate the assessment of SCCA-IgM for prognostic purposes in patients with cirrhosis.

Simple, fast, and accurate in silico estimations of contact angle, surface tension, and work of adhesion of water and oil nanodroplets on amorphous polypropylene surfaces.

In this work, two computational recipes based on atomistic molecular dynamics simulations are developed and compared to quickly and accurately quantify the interactions of amorphous polypropylene surface with water and oil. Fundamental quantities such as contact angle and surface tension are estimated in excellent agreement with the corresponding experimental values, wheras the comparable values of the work of adhesion obtained using both computational recipes confirm the internal consistency in the presented methodologies.

QSAR study of natural estrogen-like isoflavonoids and diphenolics from Thai medicinal plants.

Two species of Thai medicinal plants, Dalbergia parviflora R. (Leguminosae) and Belamcanda chinensis L. (Iridaceae), used traditionally for the regulation of menstrual disorders, have been found to contain a large number of potential estrogen-like compounds. A set of some 55 isolated isoflavonoids and diphenolics showed a wide range of estrogen activity as determined in breast cancer MCF-7 and T47D cell proliferation assays. This set of compounds was studied by means of computational techniques including quantitative structure-activity relationships (QSAR) and molecular modeling. It was found that the estrogenic potencies of the studied compounds depend mainly upon the presence/absence of hydroxyl groups attached to 3' and 5' positions of B ring of the isoflavone scaffold and the inter-atomic distance between the hydroxyl groups attached to the outer terminal positions 7 of A ring and 4' of B ring. In a QSAR model employing ligand-receptor interaction energy descriptors, the LigScore scoring function of Cerius(2) virtual screening module, which describes the receptor affinities of simultaneous binding to estrogenic receptors α and ß (ER(α) and ER(ß)), led to the best correlation between the observed estrogenic activities and computed descriptors. Consideration of independent binding to ER(α) and ER(ß) did not result in statistically significant QSAR models. It was thus concluded that simultaneous and possibly competitive interaction of the compounds with the ER(α) and ER(ß) receptors, in which the presence of hydroxyl groups at the abovementioned positions of the isoflavonoids and diphenolics molecular scaffold plays a dominant role, may determine the estrogenic potency of the considered phytochemicals.

Sodium montmorillonite silylation: unexpected effect of the aminosilane chain length.

In this work, the silylation of sodium montmorillonite (Na-MMT) was performed in glycerol using 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and 3-[2-(2-aminoethylamino)ethylamino]-propyl-trimethoxysilane. The effects on the d-spacing of sodium montmorillonite (Na-MMT) upon reaction with three aminosilanes of different chain length were studied in details by combining experimental and computational techniques. Infrared spectroscopy was used to monitor the grafting process, while the degree of grafting was calculated using thermogravimetric analysis. X-ray diffraction experiments were carried out to evaluate the shift of the (0 0 1) basal spacing. It was found that the degree of silylation of Na-MMT increases with increasing the length of the aminosilane organic moieties, the overall aminosilane concentration, and temperature. The same beneficial effects were observed on the silicate d-spacing, as its value increases with increasing silane concentration and reaction temperature. Remarkably, however, increasing the length of the organic chains in the silane modifiers resulted in decreasing values of the Na-MMT interlayer distance. A rationale for this behavior is proposed on the basis of atomistic molecular dynamics simulation evidences.

Structure and energetics of biocompatible polymer nanocomposite systems: a molecular dynamics study.

Isothermal-isobaric (NPT) molecular dynamics simulations have been performed to investigate the structure, morphology, and energetics of polymer organoclay nanocomposites based on seven nonsteroidal antiinflammatory drugs (NSAIDs), two biocompatible polymers, and hydrotalcite as the clay mineral, both in an anhydrous and in a solvated environment. The results of our theoretical computations show that nanoconfined conformations of smaller NSAIDs are more affected by the presence of water molecules in the clay gallery with respect to their larger counterparts. Moreover, the presence of water in the mineral interlayer space decreases the interaction energy between the NSAID molecules and the clay, and this detrimental effect is further enhanced by the presence of polar moieties onto the NSAIDs. Finally, from the thermodynamics standpoint, the best intercalation results in a solvated environment could be obtained with PVA in the case of less polar drugs, while PHB could be the polymer of choice in the case of highly polar NSAIDs.