Publications by authors named "Bernadett Biri"

Background: Pericardial fluid (PF) contains several biologically active substances, which may provide information regarding the cardiac conditions. Nitric oxide (NO) has been implicated in cardiac remodeling. We hypothesized that L-arginine (L-Arg) precursor of NO-synthase (NOS) and asymmetric dimethylarginine (ADMA), an inhibitor of NOS, are present in PF of cardiac patients and their altered levels may contribute to altered cardiac morphology.

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Background: Endothelial dysfunction is associated with increased levels of asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) resulting in a decreased production of nitric oxide, which regulates the vascular tone.

Methods: Patients with acute ischemic stroke (AIS, n = 55) and asymptomatic significant carotid stenosis (AsCS, n = 44) were prospectively investigated. L-arginine, ADMA, SDMA, S100 B, and high-sensitivity C-reactive protein (hsCRP) were serially measured within 6 hours after the onset of stroke, at 24 and 72 poststroke hours.

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Poly(2-ethyl-2-oxazoline), a synthetic polymer was analysed by mass spectrometry using different ion sources. Two distributions could be identified in the mass spectra which related to two different polymer series (one with hydrogen and hydroxyl end-groups and the other with methyl and hydroxyl end-groups). The fragmentation behaviour of the protonated oligomers was studied in a quadrupole time-of-flight mass spectrometer (MS) with electrospray, atmospheric pressure chemical ionization and direct analysis in real time soft ionization techniques.

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The in vitro autoxidation of N-hydroxyurea (HU) is catalyzed by Mn(III)TTEG-2-PyP(5+), a synthetic water soluble Mn(III) porphyrin which is also a potent mimic of the enzyme superoxide dismutase. The detailed mechanism of the reaction is deduced from kinetic studies under basic conditions mostly based on data measured at pH = 11.7 but also including some pH-dependent observations in the pH range 9-13.

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Relatively little is known about the reaction chemistry of the human defense factor hypothiocyanite (OSCN(-)) and its conjugate acid hypothiocyanous acid (HOSCN), in part because of their instability in aqueous solutions. Herein we report that HOSCN/OSCN(-) can engage in a cascade of pH- and concentration-dependent comproportionation, disproportionation, and hydrolysis reactions that control its stability in water. On the basis of reaction kinetic, spectroscopic, and chromatographic methods, a detailed mechanism is proposed for the decomposition of HOSCN/OSCN(-) in the range of pH 4-7 to eventually give simple inorganic anions including CN(-), OCN(-), SCN(-), SO(3)(2-), and SO(4)(2-).

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The collision-induced dissociation (CID) of protonated buprenorphine ([M+H](+) ) and four related compounds was studied by electrospray quadrupole/time-of-flight mass spectrometry (ESI-QTOF MS). The fragmentation pathways were investigated by using energy-dependent CID and pseudo-MS(3) (in-source CID combined with tandem mass spectrometry (MS/MS)) methods. The first steps of the fragmentation are the parallel losses of the substituents from the non-aromatic ring moieties.

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Objective: Asymmetric dimethylarginine (ADMA) has been associated with atherosclerosis, vascular diseases and, recently, also with arthritis including rheumatoid arthritis (RA) and ankylosing spondylitis (AS).

Methods: Serum ADMA, arginine and symmetric dimethylarginine (SDMA) levels were assessed by liquid chromatography in 61 AS and 26 osteoarthritis (OA) patients with no known cardiovascular disease.

Results: Serum ADMA levels were significantly increased in AS compared to OA patients (0.

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During the high-performance liquid chromatographic (HPLC) analysis of o-phthaldialdehyde (OPA)-derivatized amino acids such as arginine and homoarginine, we observed that the response of the fluorescence detection (FLD) system is decreased when the photodiode array detection (DAD) system (located before the FLD system) was simultaneously switched on. The decrease in the FLD response, i.e.

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