细胞技术

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 ...

The opioid and 6-acetylmorphine assays utilize gas chromatography-mass spectrometry (GC-MS) for the analysis of morphine, codeine, hydromorphone, hydrocodone, and 6-acetylmorphine in blood and urine. The specimens are fortified with deuterated internal standard and a five- ...

Analysis of clinically relevant amino acids using ion-exchange chromatography coupled to photometric detection has been an indispensable component in the detection of inborn errors of metabolism for six decades. Detection of amino acids using mass spectrometry offers advanta ...

Opiates and opioids currently rank among the most commonly prescribed pain medications. We describe two liquid chromatography tandem mass spectrometry (LC-MS-MS) methods for the quantification of morphine, codeine, hydrocodone, hydromorphone, oxycodone, oxymorphone, and ...

Urine organic acid analysis is an essential component of the workup of the patient suspected to have an inborn error of metabolism (IEM). Urine contains several hundred different organic acids, which arise from a multitude of different sources including both normal and abnormal metaboli ...

The measurement of urinary orotic acid excretion is an important test for establishing a diagnosis of hereditary orotic aciduria, a genetic defect of pyrimidine biosynthesis. Measurement of secondary urinary orotic acid elevation is also an important clinical test for the differen ...

A patient suspected of an inborn error of metabolism will commonly have urine organic acid analysis performed as part of their workup. The traditional urine organic acid method involves extraction of the acidic fraction from urine samples using an organic solvent, derivatization of extr ...

Phencyclidine (PCP) is a cycloalkylamine and is classified as a dissociative anesthetic. In the1950s, PCP was tested as an intravenous anesthetic but due to its severe side effects, it was withdrawn from the clinical use. Since then PCP has become an illegal street drug making its laboratory ana ...

Oxycodone is a semisynthetic opioid analgesic used in pain management. In the following method, gas chromatography-mass spectrometry (GC-MS) is used to determine the presence and concentration of the drug in blood and urine. The specimens are fortified with deuterated internal stand ...

A multiple reaction monitoring positive ion HPLC method with tandem mass spectrometric detection (MS-MS) for determination of sirolimus in human blood samples is described. This method utilizes an online cleanup step that provides simple and rapid sample preparation with a switchi ...

Membrane proteins (MPs) are responsible for the interface between the exterior and the interior of the cell. These proteins are involved in numerous diseases, like cancer, cystic fibrosis, epilepsy, hyperinsulinism, heart failure, hypertension and Alzheimer disease. However, stu ...

As the equivalent to gatekeepers of the cell, membrane transport proteins perform a variety of critical functions. Progress on the functional and structural characterization of membrane proteins is slowed due to problems associated with their (heterologous) overexpression. Of ...

Integral membrane proteins, in particular receptors, regulate numerous physiological functions. The primary difficulty presented by their study in vitro is to obtain them in sufficient amounts in a functional state. Escherichia coli is a host of choice for producing recombinant pro ...

Structural biology of membrane proteins is often limited by the first steps in obtaining sufficient yields of proteins because native sources are seldom. Heterologous systems like bacteria are then commonly employed for membrane protein over-expression. Escherichia coli is the m ...

Due to their implication in numerous diseases like cancer, cystic fibrosis, epilepsy, hyperinsulinism, heart failure, hypertension, and Alzheimer disease, membrane proteins (MPs) represent around 50% of drug targets. However, only 204 crystal structures of MPs have been solved. Str ...