Ultraviolet B Wavelength Dependence for the Regulation of Two Major Matrix-Metalloproteinases and Their Inhibitor TIMP-1 in Human Dermal Fibroblasts

Abstract— The wavelength dependence for the regulation of two major matrix-metalloproteinases, interstitial collagenase (MMP-1) and stromelysin-1 (MMP-3), and their major inhibitor, tissue inhibitor of metalloproteinases (TIMP-1), was studied in human dermal fibroblasts in vitro. Monochromatic irradiation at 302, 307, 312 and 317 nm with intensities ranging from 20 to 300 J/m² increased MMP-1 and MMP-3 mRNA steady-state levels and the secretion of the corresponding proteins up to 4.4-fold, whereas almost no increase was observed at wavelengths <290 nm. In contrast, the synthesis of TIMP-1 increased only marginally. This unbalance may contribute to the severe connective tissue damage related to photoaging of the skin. The wavelengths responsible for MMP-1 and MMP-3 induction reported here are distinct from the absorption spectrum of DNA and are different from results previously reported in the literature. Importantly, they overlap with wavelengths whose intensity is predicted to increase on the earth's surface upon ozone depletion. Intensities and particular wavelengths used in our studies in vitro can be absorbed readily by fibroblasts within the skin in vivo and, thus, are relevant for risk assessment and development of protective agents.     

Immobilization of antibody fragment for immunosensor application based on surface plasmon resonance

Biosurface fabrication using the Fab′ fragment of immunoglobulin (IgG) was carried out by self-assembly (SA) technique. The pepsin-digested monoclonal antibody (Mab) against bovine insulin containing the F(ab′)₂ fragment and residual proteins was separated using affinity chromatography and dialysis. To prevent the nonspecific binding of F(ab′)₂ onto gold (Au) substrate, the native disulfide bridge was reduced using dithiothreitol (DTT) to convert F(ab′)₂ into Fab′, which made the immobilization to be carried out via the native thiol (–SH) group. The fabricated biosurface using SA technique showed the formation of stable thin film through AFM topography. Through the concentration change of DTT and Fab′, the absorption characteristics against the Au surface were investigated using surface plasmon resonance (SPR) with the flow cell. The amount of immobilized antibody fragment and the antigen binding capacity were regulated with respect to the reduction state and concentration of F(ab′)₂. Based on the biosurface of the fabricated Fab′, the insulin-detection was carried out by the measurement of SPR. The proposed antibody surface could successfully detect the bovine insulin at the concentration from 100 ng/mL to 10 μg/mL.     

Palladium-catalyzed hydrocarbonation of methyleneaziridines with carbon pronucleophiles

The reaction of methyleneaziridine 1 with carbon pronucleophiles (2, H-CR₃) proceeds smoothly in the presence of a palladium catalyst affording the corresponding hydrocarbonation products 5 in good to high yield.     

Hydrogen-bonded networks from η-semiquinone complexes of manganese tricarbonyl

The cationic manganese tricarbonyl complexes containing η⁶-2-methylhydroquinone (2a), η⁶-2,3-dimethylhydroquinone (3a), η⁶-2-t-butylhydroquinone (4a), η⁶-tetramethylhydroquinone (5a) and η⁶-4,4′-biphenol (6a) are readily deprotonated to the corresponding neutral (η⁵-semiquinone)Mn(CO)₃ (2b-6b) and anionic (η⁴-quinone)Mn(CO)₃⁻ (2c-5c) complexes. The X-ray structures of 2b-6b feature strong intermolecular hydrogen bonding interactions that result in the formation of supramolecular organometallic networks. Significantly, the substitution pattern at the semiquinone ring affects the stereochemistry of the hydrogen bonding interactions. NMR spectra of 2b, 3b and 5b reveal dynamic hydrogen bonding in solution.     

Stereoselective One-Pot Synthesis of Vinyl Sulfones from Jcthyl Phenyl Sulfone

Vinyl sulfones are stereoselectively prepared in high yields in a one-pot by the Wittig-Horner reaction via phosphorylation of methyl phenyl sulfone at low temperature.     

Tetrachlorosilane Catalyzed Dithioacetalization

Tetrachlorosilane was found to be a mild as well as selective catalyst for dithioacetalization of the carbonyl compounds.     

Effect of Dissolved Oxygen Tension and Agitation Rates on Sulfur-Utilizing Autotrophic Denitrification: Batch Tests

The effect of dissolved oxygen (DO) and agitation rate in open and closed reactors was examined for sulfur-utilizing autotrophic denitrification. The reaction rate constants were determined based on a half-order kinetic model. Declining denitrification rate constants obtained for open reactors those of 8.46, 8.03, and 2.18 for 50 mg NO₃ ^?-N/L, while 11.12, 9.14, and 0.12 mg^1/2/L^1/2?h were for 100 mg NO₃ ^?-N/L at agitation speeds of 0, 100, and 200 rpm. In closed reactors, the ever-increasing denitrification rates were 10.13, 22.56, and 37.03, whereas for the same nitrate concentrations and speeds the rates were 13.17, 15.63, and 26.67 mg^1/2/L^1/2?h. The rate constants correlated well (r ² ?=?0.89–0.99) with a half-order kinetic model. In open reactors, high SO₄ ^2?/N ratios (8.02–75.10) while in closed reactors comparatively low SO₄ ^2?/N ratios (6.10–13.39) were obtained. Sulfur oxidation occurred continuously in the presence of DO, resulting in mixed cultures acclimated to sulfur and nitrate. SO₄ ^2? was produced as an end product, which reduced alkalinity and lowered pH over time. Furthermore, DO inhibited sulfur denitrification in open reactors, while agitation in closed reactors increased the rate of denitrification.