Cytochromes P450 (P450s) are major catalysts in the metabolism of xenobiotics and endogenous substrates such as estradiol (E2). It has previously been shown that E2 is predominantly metabolized in humans by CYP1A2 and CYP3A4 with 2-hydroxyestradiol (2-OHE2) the major metabolite. This study examines effects of deployment-related and other chemicals on E2 metabolism by human liver microsomes (HLM...

Human cytochrome b5 (Cyt b5) plays important roles in cytochrome P450 (CYP)-mediated drug metabolism. However, the expression level of Cyt b5 in normal human liver remains largely unknown. The effect of Cyt b5 on overall CYP activity in human liver microsomes (HLM) has rarely been reported and the relationship between Cyt b5 and the activity of polymorphic CYP has not been systematically invest...

One of the factors determining the toxicity of chlorpyrifos (CPS), an organophosphorus (OP) insecticide, is its biotransformation. CPS can be activated by cytochrome P450 (CYP) through a desulfuration reaction to form chlorpyrifos-oxon (CPO), a potent anticholinesterase. CPS can also be detoxified by CYP through a dearylation reaction. Using pooled human liver microsomes (HLM), a K(m(app)) of 3...

Flavin-containing monooxygenases (FMO) are metabolic enzymes mediating the oxygenation of nucleophilic atoms such as nitrogen, sulfur, phosphorus, and selenium. These enzymes share similar properties to the cytochrome P450 system but can be differentiated through heat inactivation and selective substrate inhibition by methimazole. This study investigated 10 compounds with varying degrees of FMO...

We propose a new approach for mixture modeling based only upon pairwise distances via the concept of hypothetical local mapping (HLM). This work is motivated by increasingly commonplace applications involving complex objects that cannot be effectively represented by tractable mathematical entities. The new modeling approach consists of two steps. A distance-based clustering algorithm is applied...

Eight inhibitory monoclonal antibodies (MAbs) individually specific to human cytochrome P-450 (P-450) 1A1, 1A2, 2A6, 2B6, 2C subfamily (2C8, 2C9, 2C18 and 2C19), 2D6, 2E1, and 3A4/5 were used to define the role of single P-450s in the metabolism of diazepam (DZ), 7-ethoxycoumarin (7-EC), and imipramine (IMI) in human liver microsomes (HLM). The MAbs were added combinatorially to six HLM samples...

In spite of the criticism for lack of validity, researchers still use single-subject designs to evaluate school counseling when working with individual students, autism treatment and many other individualized therapeutics interventions. The accumulation of many studies on one area of research creates the need for comparing the efficacy of the findings from these studies. Researchers developed s...

Abstract Background The multiorgan involvement of heart failure is similar to the spread observed in cancer. We proposed a new score, named HLM, analogous TNM classification used oncology. HLM refers (i) H: damage, instead “T” for tumor; (ii) L: lung involvement, “N” lymph nodes; (iii) M: systemic “M” metastasis. Objectives compare score NYHA class, ACC/AHA stages and left ventricular ejection ...