N(G) ,N(G) -dimethyl-l-arginine (asymmetric dimethylarginine, ADMA),N(G) -monomethyl-l-arginine (l-NMMA) and N(G) ,N(G') -dimethyl-l-arginine (symmetric dimethylarginine, SDMA) are released during hydrolysis of proteins containing methylated arginine residues. ADMA and l-NMMA inhibit nitric oxide synthase by competing with l-arginine substrate. All three methylarginine derivatives also inhibit ...

We describe the optimization and validation of a clinically feasible radioreceptor assay to detect endogenous digitalis-like factor(s) (EDLF) in human plasma and urine. The assay is based on the competitive replacement of 125I-labeled digoxin on human placenta membranes by ligands present in sample extracts. Digoxin and ouabain were used as calibrators. We also describe simple and effective met...

In this work, the first systematic characterization of triacylglycerol (TG) enantiomers in real samples using chiral high-performance liquid chromatography (HPLC) with atmospheric pressure chemical ionization mass spectrometry (APCI-MS) is performed. Our chiral HPLC/APCI-MS method is based on the use of two cellulose-tris-(3,5-dimethylphenylcarbamate) columns connected in series using a gradien...

Water (H(2)O) is the most abundant and important molecule of life. Natural water contains small amount of heavy isotopes. Previously, few animal model studies have shown that the isotopic composition of body water could play important roles in physiology and pathophysiology. Here we study the stable isotopic ratios of hydrogen (δ(2)H) and oxygen (δ(18)O) in human blood plasma. The stable isotop...

Gabapentin is an anticonvulsant widely used in the treatment of epilepsy. No peculiar chromophore is available on the gabapentin moiety for direct analysis by absorption spectrophotometry. A sensitive spectrophotometric method for the determination of gabapentin in bulk, pharmaceutical formulations and human plasma has been developed. In this method, gabapentin directly derivatized with vanilli...

Gabapentin is an anticonvulsant widely used in the treatment of epilepsy. No peculiar chromophore is available on the gabapentin moiety for direct analysis by absorption spectrophotometry. A sensitive spectrophotometric method for the determination of gabapentin in bulk, pharmaceutical formulations and human plasma has been developed. In this method, gabapentin directly derivatized with vanilli...

background: a simple and sensitive high performance liquid chromatography-electrospray ionization mass spectrometry method has been evaluated for the assignment of clonidine hydrochloride in human plasma. methods: the mobile phase composed of acetonitrile-water 60:40 (v/v) and 0.2% formic acid 20 µl of sample was chromatographically analyzed using a repacked zorbax-xdb-ods c18 column (2.1 mmx30...

abstract background and aims: multiple sclerosis (ms) is defined by the presence of inflammatory demyelinating plaques in the central nervous system (cns). it has been indicated that human herpes virus 6 (hhv-6) may play role in pathogenesis of ms. the aim of this study was to determine the presence of hhv-6 dna and anti hhv-6 igg in ms patients and controls. materials and methods: blood sample...

Background: In this study we have prepared the IgA solution from normal human plasma using plasma fractionation and ion exchange chromatography. Materials and Methods: Using fractionation of plasma with cold ethanol (starting with 8% ethanol), fraction III was prepared as a suitable source for IgA preparation. Then it was treated with caprylic acid for separation of impurities. For enrichm...