Tandem mass spectrometry of isomeric aniline-labeled N-glycans separated on porous graphitic carbon: Revealing the attachment position of terminal sialic acids and structures of neutral glycans.

Rationale: Quantitative monitoring of changes in the N-glycome upon disease has gained significance in the context of biomarker discovery. Separation and quantification of isobaric glycan isomers can be attained by using high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS). Collision-induced dissociation (CID)-based fragmentation of separated isobaric glycans is evaluated in respect to its potential of providing fragment ions specific for the linkage positions of terminal sialic acids and the presence of intersecting GlcNAc moieties, respectively.

Quantitative isomer-specific N-glycan fingerprinting using isotope coded labeling and high performance liquid chromatography-electrospray ionization-mass spectrometry with graphitic carbon stationary phase.

Glycan reductive isotope labeling (GRIL) using (12)C6-/(13)C6-aniline as labeling reagent is reported with the aim of quantitative N-glycan fingerprinting. Porous graphitized carbon (PGC) as stationary phase in capillary scale HPLC coupled to electrospray mass spectrometry with time of flight analyzer was applied for the determination of labeled N-glycans released from glycoproteins. The main benefit of using stable isotope-coding in the context of comparative glycomics lies in the improved accuracy and precision of the quantitative analysis in combined samples and in the potential of correcting for structure-dependent incomplete enzymatic release of oligosaccharides when comparing identical target proteins.

Cloning and functional expression in E. coli of a polyphenol oxidase transcript from Coreopsis grandiflora involved in aurone formation.

Polyphenol oxidases are involved in aurone biosynthesis but the gene responsible for 4-deoxyaurone formation in Asteraceae was so far unknown. Three novel full-length cDNA sequences were isolated from Coreopsis grandiflora with sizes of 1.80kb (cgAUS1) and 1.

Purification and characterization of tyrosinase from walnut leaves (Juglans regia).

Polyphenol oxidase (PPO) is a type-3 copper enzyme catalyzing the oxidation of phenolic compounds to their quinone derivates, which are further converted to melanin, a ubiquitous pigment in living organisms. In this study a plant originated tyrosinase was isolated from walnut leaves (Juglans regia) and biochemically characterized. It was possible to isolate and purify the enzyme by means of an aqueous two-phase extraction method followed by chromatographic purification and identification.

High level protein-purification allows the unambiguous polypeptide determination of latent isoform PPO4 of mushroom tyrosinase.

Tyrosinases catalyze two initial reaction steps in the formation of melanin. Purification of tyrosinases had always been a process accompanied with various problems caused by enzymatic browning processes. Here, an approach is presented for the purification of the latent enzyme from mushrooms which averts and removes interfering compounds (e.

Voriconazole pharmacokinetics and safety in immunocompromised children compared to adult patients.

The aim of this study was to investigate the pharmacokinetics and safety of voriconazole after intravenous (i.v.) administration in immunocompromised children (2 to 11 years old) and adults (20 to 60 years old) who required treatment for the prevention or therapy of systemic fungal infections.

Determination of saliva trough levels for monitoring voriconazole therapy in immunocompromised children and adults.

To evaluate the reliability and practical use of saliva for therapeutic drug monitoring of the antifungal agent voriconazole in immunocompromised patients, a paired-sample study was conducted. Plasma and saliva trough levels were measured in seven children and nine adults who required treatment for the prevention or therapy of systemic fungal infections. The pediatric patients received a voriconazole dosage of 7 mg/kg intravenously twice a day.

Determination of voriconazole in human plasma and saliva using high-performance liquid chromatography with fluorescence detection.

Voriconazole is a widely used triazole antifungal agent with a broad spectrum including Aspergillus species. A simple, sensitive and selective high-performance liquid chromatography method for the determination of voriconazole in human plasma and saliva was developed. Drug and internal standard (UK-115 794) were extracted from alkaline plasma and saliva with n-hexane-ethyl acetate (3:1, v/v) and analyzed on a Luna C 18 column with fluorimetric detection set at excitation and emission wavelengths of 254 and 372 nm, respectively.

Rapid and simple method for the analysis of nateglinide in human plasma using HPLC analysis with UV detection.

Nateglinide (NA) is a novel oral mealtime glucose regulator, recently approved for the treatment of type II diabetes mellitus. To facilitate clinical studies investigating the dependence of NA elimination on the genotype of cytochrome P450 isoenzymes, we developed a rapid HPLC method for determination of NA in human plasma samples. The validated limit of quantitation (LOQ) of 0.