Randomized trials are an excellent research design with major advantages. However, randomized trials are not immune to biases, and inferences from them may be sometimes flawed or irrelevant. The present review addresses, in brief, some of the major threats to the credibility and relevance of the results of clinical trials: power problems, biases affecting internal validity (poor design, conduct...

CYP1A2 is part of the cytochrome P450 (CYP) family of drug-metabolizing enzymes. The CYP1A2 gene is found in a cluster with CYP1A1 and CYP1B1 on chromosome 15 [1]. CYP1A2 and CYP1A1 share a 5′-flanking region of approximately 23 kb, which contains shared regulatory elements, although the genes are positioned back to back and transcription occurs in opposite directions [2]. The CYP1A2 gene spans...

The cytochrome P450 (CYP) family 1A enzymes, CYP1A1 and CYP1A2, are two of the most important enzymes implicated in the metabolism of endogenous and exogenous compounds through oxidation. These enzymes are also known to metabolize environmental procarcinogens into carcinogenic species, leading to the advent of several types of cancer. The development of selective inhibitors for these P450 enzym...

The sex-based differences between the effects of two novel sugar-based drug candidates, a sulfated polymannuroguluronate (SPMG-911) and an acidic oligosaccharide sugar chain compound (AOSC-971), on the enzymes CYP 1A2 and CYP 2E1 were investigated. The results showed that neither SPMG-911 nor AOSC-971 have any effect on CYP1A2, while AOSC-971 induced the CYP 2E1 in male rats. The results are us...

Cytochrome P450 (P450)-catalyzed oxidation of the aromatic ring of estradiol can result in 2- or 4-hydroxylation. Which of these products is formed is biologically important, as the 4-hydroxylated metabolite is carcinogenic, whereas the 2-hydroxylated metabolite is not. Most human P450 enzymes, including CYP1A1 and CYP1A2, exhibit a high preference for estradiol 2-hydroxylation, but human CYP1B...

The aim of this study was to find out whether Schizonepetin influences the pharmacokinetics of the main substrates drugs of CYP1A2, CYP3A1/2, CYP2E1, CYP2C19 and CYP2D6 in rats; the influence on the levels of CYP mRNA was also studied. Phenacetin, dapsone, chlorzoxazone, omeprazole and metoprolol were selected as probe substrates for CYP1A2, CYP3A1/2, CYP2E1, CYP2C19 and CYP2D6 respectively. HP...

Previous studies have shown that the presence of one P450 enzyme can affect the function of another. The goal of the present study was to determine if P450 enzymes are capable of forming homomeric complexes that affect P450 function. To address this problem, the catalytic activities of several P450s were examined in reconstituted systems containing NADPH-POR (cytochrome P450 reductase) and a si...

Xenobiotic metabolism in the tongue has received little attention in the literature. In the present study, we report a comparative analysis of constitutive cytochrome P450 (CYP) expression and activities in the tongue. First we compared catalytic activities of rabbit, rat and bovine tongue samples using the probe substrates 4-nitrophenol, 1-phenylethanol, caffeine and 7-ethoxycoumarin. Rabbit t...