细胞功能测定

Measurement of low concentrations of estrogens, encountered in pre-pubertal children, men, and postmenopausal women, is important for numerous clinical applications. We describe a method for high sensitivity analysis of estrogens that uses two-dimensional chromatograph ...

The mitochondrial fatty acid β-oxidation is integral to normal cellular metabolism and maintenance of cellular energy supplies. Disorders of this pathway interrupt the body’s ability to deal with fasting states, as well as compromising the functioning of organs and systems whose high ...

A detailed protocol using liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS) is described for the determination of the total homocysteine (HCY) in plasma. Sample preparation is simple and relies on the complete reduction of any homocystine ((HCY)2) or protein-bound ...

Fentanyl is a potent, short-acting synthetic opioid analgesic. Fentanyl is measured in blood and urine following mixed-mode solid phase extraction. The specimens are fortified with deuterated internal standard and a five-point calibration curve is constructed. The final extrac ...

Neuroblastoma, in most cases, is characterized by increased production of catecholamines and their metabolites. Laboratory diagnosis and clinical follow-up include the measurement of urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA). In the following proced ...

Hydroxyurea is an antineoplastic drug, which is also widely used in the treatment of sickle cell disease. Various methods including colorimetry, high performance liquid chromatography, and gas chromatography-mass spectrometry (GC-MS) are available for the assay of hydroxyurea. ...

Most (90%) cases of congenital adrenal hyperplasia (CAH) are due to mutations in the steroid 21-hydroxylase gene (Cyp21). CAH due to 21-hydroxylase deficiency is diagnosed by confirming elevations of 17-hydroxyprogesterone (OHPG) and androstenedione (ANST) with decreased corti ...

Ibuprofen is a non-narcotic, non-steroidal anti-inflammatory drug used for the treatment of pain, fever, and inflammatory diseases such as rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis. It is also used for induction of closure of patent ductus arteriosus (PDA) in ...

Indomethacin is a non-narcotic and non-steroidal anti-inflammatory drug used in the treatment of various inflammatory diseases such as rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis. In neonates, it is also used for induction of closure of patent ductus arter ...

The following chapter describes a method to measure iothalamate in plasma and urine samples using high performance liquid chromatography combined with electrospray positive ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Methanol and water are spiked with the intern ...

Acylcarnitine analysis using tandem mass spectrometry has become a powerful tool in the investigation of pediatric patients presenting with clinical signs and symptoms suggestive of fatty acid oxidation defects. These signs are diverse and include failure to thrive, feeding diff ...

Ketamine hydrochloride, a Schedule III drug under the Controlled Substances Act, is a dissociative anesthetic that has a combination of stimulant, depressant, hallucinogenic, and analgesic properties. This procedure utilizes solid phase extraction of blood, tissue, or urine sam ...

The potential for adverse effects of lead (Pb) exposure on development in children remains a health concern in the U.S., and programmatic screening of children for elevated blood lead levels ( 10μg/dL) is widespread. With sufficiently sensitive technology for the measurement of lead such as I ...

Deficiencies in any of the 50 degradative enzymes found in lysosomes results in the accumulation of undegraded material and subsequently cellular dysfunction. Early identification of deficiencies before irreversible organ and tissue damages occur leads to better clinical ou ...

Methadone is a synthetic opioid used to relieve pain, treat opioid withdrawal, and wean heroin addicts. Measurement of methadone and its major metabolite EDDP in urine is useful for assessing compliance with addiction rehabilitation and pain management programs. This method quantit ...

Medications that have a narrow therapeutic window must be regularly monitored to assist in clinical dosing. Methotrexate (MTX) is one such chemotherapeutic agent that is closely monitored using various standard assays. Patients who have renal failure and who are treated using high-do ...

Methylmalonic acid (MMA), a biochemical marker for vitamin B12 deficiency, is commonly measured in serum and urine using liquid chromatography-tandem mass spectrometry (LC-MS-MS) with electrospray ionization. Improvements in sample preparation and the ability to analyze MMA w ...

The measurement of plasma or serum methylmalonic acid (MMA) is useful for monitoring therapy in patients with methylmalonic acidemia due to methylmalonyl-CoA mutase deficiency, defects of vitamin B12 metabolism, and also for the determination of functional vitamin B12 deficienc ...

Therapeutic drug management of patients receiving mycophenolic mofetil or mycophenolate sodium using mycophenolic acid (MPA) concentrations is controversial. Considered to be less toxic compared to many of the other drugs used in immunosuppression regimens, MPA is not tolera ...

We describe a method for the quantitative analysis of nicotine, cotinine, trans-3′-hydroxy cotinine, nornicotine, and anabasine in urine, serum, and plasma using liquid chromatography-tandem mass spectrometry. A mix of deuterium-labeled internal standards (IS) is added to a speci ...