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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the effects of silica (SiO2) and titanium dioxide (TiO2) on the pulmonary recruitment of inflammatory cells and the ability of alveolar macrophages (AMs) to release the pro-inflammatory cytokines, interleukin 1 (IL-1) and tumor necrosis factor alpha (TNF). Rats were intratracheally instilled with 5 to 100 mg/kg of the materials, and bronchoalveolar lavage cell populations and AM cytokine release were characterized on days 1, 7, 14, and 28. Both dusts elicited dose-related increases in neutrophils, lymphocytes, and AMs; however, this response was more pronounced and persistent with SiO2. SiO2 at greater than or equal to 50 mg/kg increased AM release of IL-1 and TNF at all time points; lower SiO2 doses had either a transient or no effect on AM-derived cytokines. TiO2 did not result in AM IL-1 release and increased TNF release transiently at doses greater than or equal to 50 mg/kg. Both dusts primed AMs to release increased levels of IL-1 and TNF upon in vitro stimulation with lipopolysaccharide. Histopathology (day 28) demonstrated dose-related interstitial inflammation associated with SiO2 exposure, an effect that was less severe with TiO2. SiO2 doses of greater than or equal to 50 mg/kg elicited a granulomatous response. Development of granulomatous inflammation only at SiO2 doses for which persistent AM IL-1 release occurred suggests involvement of this cytokine in the formation of SiO2-induced granulomas. The ability of SiO2 to activate AM release of IL-1 and TNF in a more pronounced and persistent manner than TiO2 is likely responsible, at least in part, for the greater inflammation and pneumotoxicity associated with SiO2.
Am J Respir Cell Mol Biol 1990 Apr
PMID:Pulmonary response to silica or titanium dioxide: inflammatory cells, alveolar macrophage-derived cytokines, and histopathology. 215 74

Macrophage inflammatory proteins 1 alpha and 2 (MIP-1 alpha, MIP-2) are members of a growing family of cytokines thought to play a role in host defense. MIP-1 alpha and MIP-2 were previously identified in the mouse and shown to stimulate inflammatory cell recruitment. To better understand the potential role of MIP-1 alpha and MIP-2 in lung defense, we investigated the ability of rat lung cells to express mRNA for and/or secrete MIP-1 alpha and MIP-2 proteins in vitro and characterized expression of these cytokines in rat lung after in vivo exposure to silica (SiO2) or titanium dioxide (TiO2). In response to lipopolysaccharide, rat alveolar macrophages expressed increased levels of MIP-1 alpha and MIP-2 mRNA and secreted proteins (identified by N-terminal sequencing) homologous to mouse MIP-1 alpha and MIP-2. Rat alveolar macrophage MIP-1 alpha and MIP-2 mRNA expression was also increased by tumor necrosis factor-alpha (TNF) and adherence to plastic. Studies with a rat fibroblast and epithelial cell line demonstrated that MIP-2, but not MIP-1 alpha, expression can be detected in these cells after stimulation with TNF. Intratracheal instillation studies with SiO2 and TiO2 showed that inflammatory doses of these dusts increase MIP-1 alpha and MIP-2 mRNA expression in whole lung and that increased gene expression preceded the accumulation of inflammatory cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Respir Cell Mol Biol 1993 Mar
PMID:Macrophage inflammatory proteins 1 and 2: expression by rat alveolar macrophages, fibroblasts, and epithelial cells and in rat lung after mineral dust exposure. 838 10

There is widespread interest in capacitance immunosensor systems which directly detect antigen binding to immobilized antibody. Our system comprises an active biolayer of antibodies bound to a silicon--silicon dioxide--silicon nitride (Si-SiO2-Si3N4) surface. As with other groups, our system initially gave poorly reproducible responses on addition of antigen. We mechanically degraded the Si-SiO2-Si3N4 surface, and the responses on addition of transferrin were monitored. The mechanical degradation allowed the affinity reaction to be 'seen' capacitively. Once the system was established, a comparison of capture antibodies was performed to establish the most effective biolayer. Three affinity reactions were examined: (a) 1D2A4, monoclonal antibody (mAb) to human transferrin, as the capture layer; (b) polyclonal goat anti-human transferrin antibody (PcAb) as the capture layer; and (c) 1D2A4 with transferrin (Tf) prebound as the capture layer. There was no response to addition of transferrin where 1D2A4 was the capture layer. Addition of transferrin when the polyclonal antibody was used as the primary layer resulted in a drop in measured capacitance. Addition of goat anti-human transferrin antibody to a device with 1D2A4 plus transferrin as the capture layer also resulted in a measured capacitance decrease. There is a difference in dielectric/blocking effectiveness between the monoclonal and polyclonal antibodies.
J Mol Recognit 1998
PMID:Development of a capacitive immunosensor: a comparison of monoclonal and polyclonal capture antibodies as the primary layer. 1007 33

We have found reduced activity of tumor necrosis factor (TNF)-alpha accompanying resolving and fibrosing alveolitis induced in NMRI mice by mineral particles (MnO2 and SiO2, respectively), which is in apparent contradiction to the well-recognized proinflammatory and profibrotic activities of this cytokine. The objective of this study was to examine the mechanisms involved in this paradoxical response in NMRI mice. Although lung tissue messenger RNA (mRNA) levels for TNF-alpha were transiently (up to 15 d) and persistently (up to 120 d) upregulated in the resolving and fibrosing models, respectively, these changes were not accompanied by a parallel release of TNF-alpha protein, which was respectively transiently and persistently downregulated in bronchoalveolar lavage fluid and bronchoalveolar lavage cell cultures. The downregulation of the TNF-alpha protein was concurrent with the accumulation of recruited polymorphonuclear neutrophils (PMNs) in alveoli, and coculture experiments showed that PMN explanted from the lungs of mice treated with silica particles were able to downregulate the expression of TNF-alpha protein by naive alveolar macrophages. In addition, PMN depletion prevented the downregulation of TNF-alpha induced by silica, further establishing the role of PMNs in the downregulation of TNF-alpha. The possible degradation of TNF-alpha by proteolytic enzymes could be excluded. Marked increases in soluble p55 and p75 TNF receptors (sTNF-R), as well as in interleukin (IL)-10, paralleled the downregulation of TNF-alpha protein. The role of these mediators in the observed reduction of TNF-alpha activity was confirmed by immunoneutralizing the activity of p55 and p75 sTNF-R and by using IL-10-deficient animals. Because IL-10 also exerts profibrotic activity in addition to its antiinflammatory activity, the protracted overproduction of IL-10 observed in fibrosing alveolitis may help the understanding of why, in NMRI mice treated with silica particles, lung fibrosis develops in association with a downregulation of TNF-alpha.
Am J Respir Cell Mol Biol 1999 Jul
PMID:Soluble tumor necrosis factor (TNF) receptors p55 and p75 and interleukin-10 downregulate TNF-alpha activity during the lung response to silica particles in NMRI mice. 1038 2

We report here on the optical characterisation of Sm3+ (5 wt%): SiO2 + Al2O3 + Li2O + Na2O + MgO glass from the measurements of optical absorption spectra (at 300 K), total luminescence spectra (10-300 K) and fluorescence lifetimes (10-300 K) of the prominent emission transitions of the Sm3+ ions. Besides its spectral properties, physical and nonlinearity characterising property parameters have also been computed to understand the optical dispersive power of this glass. By the application of Judd-Ofelt parameters (omega(lambda)) of the measured absorption spectrum, the radiative transition probability factors (A) and stimulated emission cross-section (sigma(p)E) of the observed fluorescent levels have been analysed. Both emission intensity and measured lifetimes of the prominent luminescent transition (4G(5/2) --> 6H(7/2)) concerning Sm3+-glass has been showing a descending trend with the rise in temperature with N2-laser (337.1 nm) as the source of excitation.
Spectrochim Acta A Mol Biomol Spectrosc 2000 Jan
PMID:Temperature dependent luminescence characteristics of Sm3+-doped silicate glass. 1072 59

Rabbit liver Cd-metallothionein (CdMT) and Cd-complex of synthetically prepared pentapeptide (gamma-Glu-Cys)2-Gly were studied as examples of animal and plant metallothioneins. Using hanging mercury electrode, cathodic stripping voltammetry after adsorptive accumulation of the Cd(II)-SR complex at different potentials, is suitable for estimating changes occurring in metal coordination due to the presence of metal ions such as Zn2+, Cu2+, Hg2+ or excessive Cd2+. Conditions under which similar behaviour can be observed for both CdMT and Cd-pentapeptide complex are specified. On carbon electrodes, detailed study of reduction processes of Cd(II)-SR complexes is prevented by occurrence of a large catalytic current; oxidation processes are more suitable for study at these electrodes. Carbon composite paste electrode (10% SiO2) allows deposition of Cd(II)-SR complex during its reduction, as was demonstrated with Cd-cysteine, CdMT or Cd-pentapeptide complex. After deposition, oxidation peak of the uncomplexed Cd2+ ions and one or two oxidation peaks corresponding to a formation of the RS-Cd(II) complex are observed. Also, similarly as on Hg electrode, it was observed that excessive Cd2+ or Zn2+ ions influence oxidation peaks of the RS-Cd(II) complex formation. Combination of measurements on mercury electrode and composite paste electrode is recommended for studies of metallothionein interactions with metal ions or other metal complexes.
Cell Mol Biol (Noisy-le-grand) 2000 Mar
PMID:Voltammetry on mercury and carbon electrodes as a tool for studies of metallothionein interactions with metal ions. 1077 18

In this work application of IR spectra for the determination of silcooxygen ring types in framework silicates structures has been presented. Results of the spectra interpretation for cyclosilicates ('isolated' silicooxygen rings) have been adopted for the spectra of highly polymerized SiO2 structures. In such structures, silicooxygen rings are interconnected. In this work, spectra of three basic polymorphous SiO2 types, i.e. cristobalite, tridymite quartz (in various temperature forms) and v-SiO2 are discussed. It has been shown that identification of rings is possible after precise analysis of the spectra preceded by mathematical decomposition.
Spectrochim Acta A Mol Biomol Spectrosc 2000 Aug
PMID:Identification of silicooxygen rings in SiO2 based on IR spectra. 1095 44

An ultraviolet absorption, as well as Stokes and anti-Stokes Raman resonance scattering of spectroscopically pure SiO2 was investigated by flash photolysis technique. The whole spectrum of 'absorption and scattered bands' was recorded photographically in ultraviolet. A resonance absorption line was observed at 288.2 nm, without structure, while scattered lines were observed at 285-288.2 and 288.2-290 nm.
Spectrochim Acta A Mol Biomol Spectrosc 2000 Sep
PMID:Electronic absorption and Raman resonance scattering of spectroscopically pure SiO2. 1098 81

Two glasses doped with 1 mol% Nd2O3 and batch compositions inside the miscibility gap of the ternary Na2O-B2O3-SiO2 system were prepared by rapid quenching of the 1,400 degrees C melts. Phase separation was induced by heat-treatment at 600 degrees C for different exposure times and monitored qualitatively by an observation of Rayleigh scattering. The 4I(9/2-->P(1/2) transition of Nd3+ around 23300 cm(-1) recorded for the quenched samples without heat-treatment was used to demonstrate that submicroscopic phase separation in the doped glasses occurs instantaneously upon quenching. The effect of the Nd3+ concentration on this submicroscopic phase separation was investigated.
Spectrochim Acta A Mol Biomol Spectrosc 2001 Sep 01
PMID:Investigation of phase separation in Nd3+ doped ternary sodium borosilicate glasses by optical spectroscopy. 1166 79

Si/SiO2 superlattices are recently under investigation to add optical functionality to silicon based microelectronics. In such superlattices quantum-confinement should drive Si to become a good light emitter. Emission properties can be further improved and controlled by placing the emitter in optical microcavities. In this paper emission properties of (Si/SiO2), superlattices grown by Low Pressure Chemical Vapour Deposition will be compared with the ones obtained by other growth techniques and the origin of the emission will be discussed. Emission properties can be further improved and controlled by placing the emitter in optical microcavities. Optical properties of microcavities produced with standard complementary metal-oxide-semiconductor techniques containing Si/SiO2 superlattices as light emitter will be reviewed and a comparison between properties estimated from calculations and experiments will be given.
Spectrochim Acta A Mol Biomol Spectrosc 2001 Sep 01
PMID:Photoluminescence from (Si/SiO2)n superlattices and their use as emitters in [SiO2/Si]n SiO2 [Si/SiO2]m microcavities. 1166 82


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