The Experts below are selected from a list of 9105 Experts worldwide ranked by ideXlab platform
Kevin K. Lehmann - One of the best experts on this subject based on the ideXlab platform.
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Detection of S-Nitroso Compounds by use of midinfrared cavity ring-down spectroscopy.
Analytical chemistry, 2015Co-Authors: Vitali I. Stsiapura, Vincent K. Shuali, Benjamin Gaston, Kevin K. LehmannAbstract:S-Nitroso Compounds have received much attention in biological research. In addition to their role as nitric oxide donors, there is growing evidence that these Compounds are involved in signaling processes in biological systems. Determination of S-nitrosylated proteins is of great importance for fundamental biological research and medical applications. The most common method to assay biological S-Nitroso Compounds is to chemically or photochemically reduce SNO functional groups to release nitric oxide, which is then entrained in an inert gas stream and detected, usually through chemiluminescence. We report a method of S-Nitroso compound detection using cavity ring-down measurements of gaseous NO absorbance at 5.2 μm. The proposed method, in contrast to the chemiluminescence-based approach, can be used to distinguish isotopic forms of NO. We demonstrated sensitivity down to ∼2 pmol of S14NO groups and ∼5 pmol of S15NO groups for S-Nitroso Compounds in aqueous solutions. The wide dynamic range of cavity rin...
John S. Wishnok - One of the best experts on this subject based on the ideXlab platform.
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Nitrate, nitrite and N-Nitroso Compounds.
European journal of pharmacology, 1994Co-Authors: Sharat D. Gangolli, Piet A. Van Den Brandt, Victor J. Feron, Christine Janzowsky, Jan H. Koeman, Gerrit J.a. Speijers, Berthold Spiegelhalder, Ronald Walker, John S. WishnokAbstract:A risk assessment has been made on nitrate, nitrite and N-Nitroso Compounds encountered in the human diet. Vegetables constitute a major source of nitrate providing over 85% of the average daily human dietary intake. Nitrite and N-Nitroso Compounds present in the diet contribute relatively small amounts to the body burden and the major source of these biologically reactive Compounds is derived from the bacterial and mammalian metabolism of ingested nitrate. Additionally, endogenous synthesis provides an important source contributing to the body burden of nitrate. Data from animal toxicological studies, human effects and epidemiological surveys have been reviewed and evaluated. It is concluded that there is no firm scientific evidence at present to recommend drastic reductions beyond the average levels of nitrate encountered in vegetables grown in keeping with good agricultural practice. Recommendations have also been made for further animal and human studies to be carried out to elucidate the potential risks to man from ingested nitrate.
O.g. Ekindjian - One of the best experts on this subject based on the ideXlab platform.
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N-Nitroso Compounds, nitrite and pH in human fasting gastric juice.
Carcinogenesis, 1994Co-Authors: J.l. Paul, M. Gaudric, J. Guerre, J. Younger, O.g. EkindjianAbstract:Total N-Nitroso Compounds, ethyl acetate-extractable N-Nitroso Compounds and nitrite were measured in 146 samples of fasting gastric juice to investigate their relationship with pH. A positive correlation was found between pH and extractable N-Nitroso Compounds (r = 0.206, P < 0.02), whereas total N-Nitroso Compounds were pH-independent. It was inferred that pre-cancerous conditions associated with high gastric pH may be produced by an increase in the extractable N-Nitroso Compounds, which constitute only a small fraction of the total gastric N-Nitroso Compounds.
Vitali I. Stsiapura - One of the best experts on this subject based on the ideXlab platform.
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Detection of S-Nitroso Compounds by use of midinfrared cavity ring-down spectroscopy.
Analytical chemistry, 2015Co-Authors: Vitali I. Stsiapura, Vincent K. Shuali, Benjamin Gaston, Kevin K. LehmannAbstract:S-Nitroso Compounds have received much attention in biological research. In addition to their role as nitric oxide donors, there is growing evidence that these Compounds are involved in signaling processes in biological systems. Determination of S-nitrosylated proteins is of great importance for fundamental biological research and medical applications. The most common method to assay biological S-Nitroso Compounds is to chemically or photochemically reduce SNO functional groups to release nitric oxide, which is then entrained in an inert gas stream and detected, usually through chemiluminescence. We report a method of S-Nitroso compound detection using cavity ring-down measurements of gaseous NO absorbance at 5.2 μm. The proposed method, in contrast to the chemiluminescence-based approach, can be used to distinguish isotopic forms of NO. We demonstrated sensitivity down to ∼2 pmol of S14NO groups and ∼5 pmol of S15NO groups for S-Nitroso Compounds in aqueous solutions. The wide dynamic range of cavity rin...
S. Bruce King - One of the best experts on this subject based on the ideXlab platform.
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Ring expansions of acyloxy Nitroso Compounds.
Tetrahedron letters, 2015Co-Authors: Mallinath B. Hadimani, Rajeswari Mukherjee, Ranjan Banerjee, Mai E. Shoman, Omar M. Aly, S. Bruce KingAbstract:Treatment of cyclopentanone and cyclobutanone-derived oximes with lead (IV) tetraacetate gives the bright blue acyloxy Nitroso Compounds, which upon basic hydrolysis yields the ring expansion product cyclic hydroxamic acids in 12-81% yield. Reactions of substituted cyclopentanones provide ring expanded products where the -NOH group regioselectively inserts to the more substituted position and gives a better yield compared to the treatment of the same ketone with a basic solution of Piloty's acid. Reaction of phosphines with acyloxy Nitroso Compounds generally generates a ring-expanded Beckmann rearrangement product that can be hydrolyzed to the corresponding lactam. Acyloxy Nitroso Compounds that undergo rapid hydrolysis to HNO do not show this ring expansion reactivity. These results further demonstrate the versatility of acyloxy Nitroso compound to yield structurally complex materials.