Serine palmitoyltransferase (SPT) catalyzes the condensation of l-serine and palmitoyl-CoA, which is the rate-limiting step in the de novo synthesis of sphingolipids. SPT activity is commonly measured by monitoring the incorporation of radiolabeled l-serine into 3-ketodihydrosphingosine. In this article, we introduce several adaptations of the established protocol to improve sensitivity, reprod...

This work proposes a procedure to estimate the measurement uncertainty for the quantification of cefazolin by high-performance liquid chromatography (HPLC) and microbiological assay (bioassay). HPLC method was performed according to United States Pharmacopeia (USP) and bioassay according to Brazilian Pharmacopeia (FB). The quantification of cefazolin by high-performance liquid chromatography wa...

Objectives: To perform stability indicating analytical method development and validation of Lafutidine in tablet dosage form by reverse phase HPLC method. Materials and Methods: The method was developed employing isocratic RP-HPLC and validated for assay of Lafutidine in tablet dosage form. The method employs the use of a UV detector. Results: The developed assay method was found to be accurate...

We report an HPLC assay for melatonin that incorporates automated injection, methanol/water mobile phase, and fluorescence detection. Plasma samples were extracted by solid and liquid phases. Recovery was > 70% for 1-10 mL of plasma extracted, approximately 40 pg-250 ng of melatonin. Samples were dried and reconstituted in 100 mL/L methanol. Injections were 25 microL or 150 microL, depending on...

human leukocytes cause activating mutations in the K-ras protooncogene. Nakajima T. K-ras gene point mutation in neo-genetic lesions of subpleural fibrotic lesions: either an early genetic event in lung cancer development or a non-specific genetic change during the inflammatory reparative process. Topographic analysis of K-ras mutations in histologically normal lung tissues and tumours of lung ...

Introduction Aminoglycoside antibiotics are proven medications for both human and veterinary use with broad-spectrum activity, particularly against gram negative bacteria.1 Many of these antibiotics are manufactured by bacterial culture (fermentation) processes, and as such can be a mixture of active compounds and not a single chemical compound. One example of an antibiotic manufactured by ferm...

This automated assay determines the concentration of the antidepressant fluoxetine (Prozac) and its active metabolite norfluoxetine in serum by reversed-phase HPLC with spectrophotometric detection. Extraction, injection, and quantification are performed by the Gilson Aspec automated sample handler. The patient's specimen, with added protriptyline as internal standard, is extracted with solid-p...

The determination of creatinine by HPLC was performed by direct injection of serum onto the column, and after ultrafiltration of the sample, and the results were compared. A modified weak cation exchange column was used for HPLC. This eliminates the protein displacement effect and the Gibbs-Donnan effect, thus permitting a rapid direct analysis. Three of the four ultrafiltration methods gave al...

Received July 19, 2005; revision accepted for publication October 20, 2005. Correspondence: Hiroko Taniai, Department of Pediatrics, Neonatology and Congenital Disorders, Nagoya City University Graduate School of Medical Sciences, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan. e-mail: [email protected] A Simple Quantitative Assay for Urinary Adenosine Using Column-Switching Hig...

A stability-indicating liquid chromatographic (LC) method was developed for the determination of posaconazole in bulk. Chromatographic separation was achieved using an isocratic elution in a reversed-phase system, with a mobile phase composed of methanol-water (75:25, v/v), at 1.0 mL min(-1) flow. Samples were exposed to degradation under thermal, oxidative and acid/basic conditions, and no int...