Accurate quantification of cytochrome P450 (P450) protein contents is essential for reliable assessment of drug safety, including the prediction of in vivo clearance from in vitro metabolism data, which may be hampered by the use of uncharacterized standards and existence of unknown allelic isozymes. Therefore, this study aimed to delineate the variability in absolute quantification of polymorphic CYP2D6 drug-metabolizing enzyme and compare immunoblot and nano liquid chromatography coupled to mass spectrometry (nano-LC/MS) methods in identification and relative quantification of CYP2D6.1 and CYP2D6.
View Article and Find Full Text PDFWe report a tetrazole-based, photoclick chemistry that can be employed to selectively functionalize an alkene genetically encoded in a protein inside E. coli cells. The reaction involved the treatment of E.
View Article and Find Full Text PDFAim: To investigate the effect of omega-3 fatty acid parenteral supplementation postoperatively on clinical outcomes and immunomodulation in colorectal cancer patients.
Methods: Forty-two patients undergoing radical colorectal cancer resection with an indication for total parenteral nutrition postoperatively were enrolled in this prospective, double-blind, randomized, controlled study. Patients received total parenteral nutrition supplemented with either soybean oil (LCT; Intralipid, Fresenius-Kabi, SO group, n = 21) or a combination of omega-3 fish oil and soybean oil (LCT:fish oil = 5:1, fish oil; Omegaven, Fresenius-Kabi, FO group, n = 21), up to a total of 1.
Genome-wide transcriptional profiling is now feasible, and profiling of the proteome, although technically challenging, is advancing rapidly. Expression profiling provides a tool to accelerate discovery in a broad range of sciences, but its greatest impact on human health may be on the process of drug discovery and therapy development, and investigation of the functional networks underlying drug responses of diseased and normal tissue. For anticancer agents in particular, antitumor effects and toxicities to critical normal tissues may rest in a delicate balance that is governed by complex pharmacokinetic (PK) and pharmacodynamic (PD) inter-relationships.
View Article and Find Full Text PDFMany bacteria use nonribosomal peptide synthetase (NRPS) proteins to produce peptide antibiotics and siderophores. The catalytic domains of the NRPS proteins are usually linked in large multidomain proteins. Often, additional proteins are coexpressed with NRPS proteins that modify the NRPS peptide products, ensure the availability of substrate building blocks, or play a role in the import or export of the NRPS product.
View Article and Find Full Text PDFLow-dose corticosteroids may provide a favorable benefit/risk ratio for many therapeutic applications. However, the extremely low plasma drug concentrations achieved, in conjunction with the insufficient sensitivity/ selectivity of current analytical methods, renders the evaluation of corticosteroid pharmacokinetics (PK) a significant challenge under such conditions. Furthermore, targeted therapeutic strategies involving administration by inhalation or intraocular injection could result in very low but sustained systemic corticosteroid concentrations, which must be quantified to determine potential side effects.
View Article and Find Full Text PDFGene expression changes underlie important biological and pharmacological responses. Although mRNA expression profiling is routine, quantification of low-abundance proteins, which typically represent key effectors of responses, remains challenging. A novel strategy was developed for sensitive and accurate quantification of low-abundance proteins in highly complex biological matrixes.
View Article and Find Full Text PDFSALL4, a human homolog to Drosophila spalt, is a novel zinc finger transcriptional factor essential for development. We cloned SALL4 and its isoforms (SALL4A and SALL4B). Through immunohistochemistry and real-time reverse-transcription-polymerase chain reaction (RT-PCR), we demonstrated that SALL4 was constitutively expressed in human primary acute myeloid leukemia (AML, n = 81), and directly tested the leukemogenic potential of constitutive expression of SALL4 in a murine model.
View Article and Find Full Text PDFIn recent years, dietary supplements and herbal medicines are increasing in popularity all over the world. However, it is problematic that some manufacturers illegally included synthetic drugs in their products. Due to the extremely complex matrices of those products, most existing methods for screening illegal adulterations are time-consuming and liable to false positive.
View Article and Find Full Text PDFRapid Commun Mass Spectrom
November 2005
Isotope-coded affinity tag (ICAT) methods, in conjunction with capillary liquid chromatography/tandem mass spectrometry (LC/MS/MS), represent a promising approach for accurate protein quantification. However, sensitivity remains a challenge for the quantification of low-copy proteins in complex biological matrices. Here we investigated the electrospray ionization (ESI) and collision-activated dissociation (CAD) behavior of peptides derivatized with the cleavable ICAT (cICAT) reagent.
View Article and Find Full Text PDFZhonghua Wai Ke Za Zhi
June 2005
Objective: To demonstrate the prognostic value of neuroendocrine clone on colorectal carcinoma.
Methods: The immunochemistry methods were used to investigate the percent of neuroendocrine carcinoma in 73 human colorectal carcinoma. Retrospective analysis and follow-up were carried out in all patients.
A rapid, selective, and reliable strategy has been developed for the screening and identification of glycosides in biological samples: a crude extract was directly infused to a triple-quadrupole MS/MS, and major glycosides were screened out with high confidence by an energy-gradient neutral loss scan (EGNLS) for the loss of sugar(s); then these glycosides were further identified with LC/MS/MS. The proposed EGNLS method was established and optimized with 16 representative glycosides (including ginsenosides and the glycosides of flavones, anthraquinones, and terpenoids). The EGNLS method has two major advantages over the conventional fixed-energy neutral loss scan: (1) The latter is liable to '"omit" some target compounds due to the usual mismatch between the preset collision energy and interested compounds' optimal collision energy (OCE), while EGNLS solves this problem by scanning over an energy range.
View Article and Find Full Text PDFQuantitation of amino acids in complex matrixes without derivatization is advantageous; however, difficulties exist in both the separation and the detection of those compounds. A validated method that is based on the use of volatile ion-pair liquid chromatography coupled to stable isotope dilution tandem mass spectrometry has been developed for the simple and accurate quantitation of underivatized amino acids in biological samples. Sufficient separation of 22 underivatized amino acids was achieved on a C18 column in 36 min using perfluoroheptanoic acid (PFHA) and trifluoroacetic acid (TFA) as mobile phase modifiers.
View Article and Find Full Text PDFDetermination of amino acids in a complex matrix without derivatization is advantageous, however, difficulties are found in both the detection and the separation of those compounds. In this study, a rapid and reliable LC-MS-MS method for the quantitation of underivatized amino acids in exocellular media was established. Injections were made directly after centrifugation of the samples, without further preparation.
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