Crosstalk Between Co-cultured A549 Cells and THP1 Cells Exposed to Cigarette Smoke.

Cigarette smoke (CS) is considered as a major etiological factor in the pathogenesis of chronic obstructive pulmonary disease. In this study we used A549 cells and THP-1 cells grown for 24 h in monoculture or in co-culture in CS-conditioned media and changes in their proliferation, viability, acetylated histone H3 levels and expression of extracellular antigens CD14, HLA-DR, CD11a, and CD11b were assessed. CS was highly toxic to A549 cells but not to THP1 cells. In A549 cells, oxidative stress reached the highest values after 1 h of CS exposure and then decreased. In THP1 cells oxidative stress was lower and increased progressively with time. CS decreased proliferation of A549 and THP1 cells by about 80% and 21%, respectively. CS did not alter acetylated histone H3 levels in A549 cells, while in THP1 cells the levels were reduced by about 35%. CS significantly increased expression of CD14, HLA-DR, CD11a, and CD11b in THP1 cells. In co-culture, naïve or CS-pretreated THP1 cells significantly protected A549 cells against CS toxicity but had higher death rates. These results show that epithelial cells are more fragile to CS than monocytes and that CS-activated monocytes may protect epithelial cells against CS-induced cytotoxicity.

Gas-phase NMR measurements, absolute shielding scales, and magnetic dipole moments of 29Si and 73Ge nuclei.

New gas-phase NMR measurements of the shielding constants of 29Si, 73Ge, and 1H nuclei in SiH4 and GeH4 are reported. The results, extrapolated to zero density, provide accurate isolated molecule values, best suited for comparison with theoretical calculations. Using the recent ab initio results for these molecules and the measured chemical shifts, we determine the absolute shielding scales for 29Si and 73Ge. This allows us to provide new values of the nuclear magnetic dipole moments for these two nuclei; in addition, we examine the dipole moments of 13C and 119Sn.

Rovibrationally averaged nuclear shielding constants in OCS.

The nuclear shielding constants in OCS are studied using ab initio theoretical methods and gas-phase NMR measurements. The shielding surfaces are calculated and the rovibrational effects and the resulting temperature dependence are analyzed. The temperature dependence of 13C shielding in the gas phase is determined experimentally in the range 278-373 K. 13C is the single nucleus for which the experimental data for the temperature dependence can be converted to a reference-independent scale, and good agreement of the measured and calculated ab initio results is observed. For 33S, we discuss a new, more accurate absolute shielding scale.

A comparison of the experimental and ab initio values of the 17O NMR chemical shifts in the carbonyl group.

New experimental and theoretical results are presented for the NMR shielding of oxygen in the carbonyl group. The experimental values clearly demonstrate that the solvent effects are very significant. The new results for the chemical shifts are in better agreement than the previous literature data with the corresponding ab initio values calculated for isolated molecules.

Ab initio calculation of 1H and 13C NMR shielding constants in solid acetylene.

The gauge-independent atomic orbital (GIAO) method has been used within the coupled Hartree-Fock (CHF) approximation to compute 1H and 13C NMR shielding constants for solid acetylene. As the amount of surrounding crystal lattice is increased, the shielding anisotropy of the carbon nuclei decreases and that of the protons increases. The influence of intermolecular interactions on the 13C shielding constant is non-additive. The GIAO approach at the HF level is sufficiently sensitive to differentiate between the two polymorphic forms of acetylene.

Ab initio calculations of the 1H and 14N NMR shielding constants in solid ammonia.

The gauge-independent atomic orbital (GIAO) approach is used within the coupled Hartree-Fock (CHF) approximation to compute the 1H and 14N NMR shielding constants in solid ammonia. A comparison with gaseous NH3 shows that (a) both shielding constants are decreased to values belonging to the liquid state and (b) anisotropies of the two shielding constants are changing in opposite directions, i.e. a decrease for the nitrogen nucleus and an increase, smaller than the decrease, for the protons are observed.

Biodesulfurization of water-soluble coal-derived material by Rhodococcus rhodochrous IGTS8.

Rhodococcus rhodochrous IGTS8 was previously isolated because of its ability to use coal as its sole source of sulfur for growth. Subsequent growth studies have revealed that IGTS8 is capable of using a variety of organosulfur compounds as sources of sulfur but not carbon. In this article, the ability of IGTS8 to selectively remove organic sulfur from water-soluble coal-derived material is investigated. The microbial removal of organic sulfur from coal requires microorganisms capable of cleaving carbon-sulfur bonds and the accessibility of these bonds to microorganisms. The use of water-soluble coal-derived material effectively overcomes the problem of accessibility and allows the ability of microorganisms to cleave carbon-sulfur bonds present in coal-derived material to be assessed directly. Three coals, two coal solubilization procedures, and two methods of biodesulfurization were examined. The results of these experiments reveal that the microbial removal of significant amounts of organic sulfur from water-soluble coal-derived material with treatment times as brief as 24 h is possible. Moreover, the carbon content and calorific value of biotreated products are largely unaffected. Biotreatment does result, however, in an increased hydrogen and nitrogen content and a decreased oxygen content of the coal-derived material. The aqueous supernatant obtained from biodesulfurization experiments does not contain sulfate, sulfite, or other forms of soluble sulfur at increased concentrations in comparison with control samples. Sulfur removed from water-soluble coal-derived material appears to be incorporated into biomass.