Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0037116 (silicosis)
 1,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Silica dust particles in the form of quartz (but not kaolin) have been hypothesized to promote pulmonary diseases such as silicosis. The hypothesis is that quartz and kaolin have a comparable membranolytic potential on a specific surface area basis, and they have a comparable cytotoxic potential for lavaged pulmonary macrophages. Suppression of the cytotoxic activity occurs when these dust particles are treated with dipalmitoylphosphatidylcholine (DPPC), a common phospholipid component of the lung pulmonary surfactant. However, the enzyme phospholipase A2 is known to digest the phospholipid component more readily in the presence of quartz than kaolin. Since surface silanol (Si-OH) and aluminol (Al-OH) groups may interact differently with the phospholipid, an understanding of the selective removal of phospholipid by PLA2 may explain in vivo differences in cytotoxicity between quartz and kaolin. To develop some insight into this phenomenon, the interaction between a phospholipid and silica particles was examined by performing ab initio DFT calculations on clusters constructed with small (one or two silica tetrahedral units) representative parts of the silicate surface and the phospholipid head group. The clusters consisted of a phospholipid head group or functional groups from the head group complexed with Si(OSiH 3) 3OH, Al(OSiH 3) 3OH (-) or Al(OSiH 3) 3OH 2. Fully optimized geometries of the complexes were used to determine binding energies, -OH vibrational frequency shifts, and NMR chemical shieldings. Results indicate that interaction of the protonated aluminol group (Al-OH 2 (+)) with the phosphate portion of the head group is strongest, while interaction of the -OH 2 (+) group with the trimethyl-choline moiety of the head group is weakest. The presence of the choline moiety increased the magnitude of the -OH vibrational frequency shifts, and the shifts were significantly larger in complexes with protonated aluminol groups relative to silanol complexes. Analysis of ChelpG atomic charges shows that a net transfer of charge occurs from the silica unit to the head group within the complexes.
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PMID:Interaction of the phospholipid head group with representative quartz and aluminosilicate structures: an ab initio study. 1847 31

Single and geminal hydroxyl species in silicas have been characterized using solid-state (29)Si NMR spectroscopy. Differentiating hydroxyl types is important in understanding their roles in chemical toxicity mechanisms for inhaled crystalline silicas responsible for silicosis. (1)H-(29)Si cross polarization NMR spectroscopy has been employed to obtain (29)Si NMR chemical shift data and signal accrual and relaxation characteristics. Spectral deconvolution is used to examine relative single and geminal hydroxyl resonance areas for a series of representative silicas and silica gels. Silicon-containing materials examined include 1878a quartz, and 1879a cristobalite from the National Institute for Science and Technology, kaolin, and several widely used respirable silicas and silica gels. Geminal hydroxyls were observed in every case, with relative resonance areas accounting for 21-65% of total hydroxyl signals. Factors affecting relative areas measured as a function of contact time, relaxation, and surface area are discussed. Subsequent (29)Si and (31)P NMR studies of a silica coated with various sodium hydrogen phosphates show preferential single silanol-phosphate interaction for basic phosphates, and oligomerization products for acidic phosphates. Geminal hydroxyl resonance areas displayed significant error (4-17%) for low surface area silicas, limiting this method to studies exhibiting major changes in chemical or spectroscopic properties.
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PMID:Differentiating and characterizing geminal silanols in silicas by (29)Si NMR spectroscopy. 2082 48

Prismatomeris connata was a kind of Rubiaceae plant for treatment of hepatitis, hepatic fibrosis and silicosis. Whereas, the effective components of Prismatomeris connata remains unexplored. The aim of this study was to investigate the inhibitory effects and mechanisms of Rubiadin isolated from Prismatomeris connata against HBV using HepG2.2.15 cells. The levels of hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and hepatitis B core antigen (HBcAg) in the supernatants or cytoplasm were examined using by enzyme-linked immunosorbent assay. HBV DNA was qualified q-PCR. Rubiadin was isolated by silica gel column. The structure of the compound was elucidated by HPLC, FT-IR, 1 H-NMR, 13 C-NMR and identified as 1,3-Dihydroxy-2-methyl-9, 10-anthraquinone. Rubiadin significantly decreased HBeAg,HBcAg secretion level and inhibit HBV DNA replication. Rubiadin inhibits the proliferation of the cells and HBx protein expression in a dose-dependent manner. The intracellular calcium concentration was significantly reduced. These results demonstrated that Rubiadin could inhibit HepG2.2.15 cells proliferation, reduce the level of HBx expression, and intracellular free calcium, which might become a novel anti-HBV drug candidate.
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PMID:Effects of Rubiadin isolated from Prismatomeris connata on anti-hepatitis B virus activity in vitro. 2904 68