Fiber optic pH sensing with long wavelength excitable Schiff bases in the pH range of 7.0-12.0

PubMed ID: 17386792Most of the fluorescent pH probes work near neutral or acidic regions of the pH scale. In this work, two different fluorescent Schiff bases, chloro phenyl imino propenyl aniline (CPIPA) and nitro phenyl imino propenyl aniline (NPIPA), have been investigated for pH sensing in the alkaline region. Absorption and emission based spectral data, quantum yield, fluorescence lifetime, photostability and acidity constant (pKa) of the Schiff bases were determined in conventional solvents and in PVC. The long wavelength excitable immobilized Schiff bases CPIPA (?ex = 556 nm) and NPIPA (?ex = 570 nm) exhibited absorption and emission based optical response to proton in the pH range of 8.0-12.0 and 7.0-12.0, respectively. Response of the CPIPA was fully reversible within the dynamic working range. The response times were between 3-13 min. A relative signal change of 95% and 96% have been achieved for sensor dyes of CPIPA and NPIPA, respectively. The CPIPA displayed better fluorescence quantum yield (?{symbol}F = 3.7 × 10-1) and higher matrix compatibility compared to NPIPA (?{symbol}F = 1.6 × 10-1) in immobilized PVC. The CPIPA and NPIPA exhibited a slight cross sensitivity to the ions of Hg+ and Fe3+, respectively. © 2007 Elsevier B.V. All rights reserved.104M268We thank Prof. Dr. Jean-Marie Salmon and Dr. Anne-Cecile Ribou for allowing time resolved based studies in their laboratory. Funding for this research was provided by the TUBITAK (Kariyer Project—104M268) and Scientific Research Funds of Dokuz Eylul University (Project No.: 2005 KB Fen 18). -

A rare urea cycle disorder in a neonate: N-acetylglutamate synthetase deficiency

Urea cycle disorders (UCD), are genetically inherited diseases that may have a poor outcome due to to profound hyperammonemia. We report the case of a baby girl diagnosed as N-acetylglutamate synthase (NAGS) deficiency. The patient was evaluated due to diminished sucking and hypotonicity. Physical examination showed hepatomegaly. Complete blood count, biochemical values and blood gas analyses were normal, acute phase reactants were negative. Further laboratory analyses showed no ketones in blood and highly elevated ammonia. Metabolic tests were inconclusive. Emergency treatment was initiated immediately and she was discharged on the 15th day of admission. NAGS deficiency was confirmed by DNA-analysis. She is now without any dietary restriction or other medication, except N-carbamylglutamate (NCG). NAGS deficiency is the only UCD which can be specifically and effectively treated by NCG. Early recognition of disease will lead to early treatment that may prohibit devastating effects of hyperammonemia

A rare urea cycle disorder in a neonate: N-acetylglutamate synthetase deficiency

Urea cycle disorders (UCD), are genetically inherited diseases that may have a poor outcome due to to profound hyperammonemia. We report the case of a baby girl diagnosed as N-acetylglutamate synthase (NAGS) deficiency. The patient was evaluated due to diminished sucking and hypotonicity. Physical examination showed hepatomegaly. Complete blood count, biochemical values and blood gas analyses were normal, acute phase reactants were negative. Further laboratory analyses showed no ketones in blood and highly elevated ammonia. Metabolic tests were inconclusive. Emergency treatment was initiated immediately and she was discharged on the 15th day of admission. NAGS deficiency was confirmed by DN A-analysis. She is now without any dietary restriction or other medication, except N-carbamylglutamate (NCG). NAGS deficiency is the only UCD which can be specifically and effectively treated by NCG. Early recognition of disease will lead to early treatment that may prohibit devastating effects of hyperammonemia