Sterol delta22-desaturase has been purified from a strain of Candida glabrata with a disruption in the gene encoding sterol 14alpha-demethylase (cytochrome P-45051; CYP51). The purified cytochrome P-450 exhibited sterol delta22-desaturase activity in a reconstituted system with NADPH-cytochrome P-450 reductase in dilaurylphosphatidylcholine, with the enzyme kinetic studies revealing a Km for er...

Steroid-induced difference spectra have been used to examine the combination of cholesterol with adrenal mitochondrial cytochrome P-450 which participates in cholesterol side chain cleavage (P-450,,,) and the depletion of cholesterol from the cytochrome which results from turnover of the enzyme system. Type I difference spectra induced by cholest5-ene-3fi,25-diol (25-hydroxycholesterol) and cho...

Cholera toxin (CT), the causative agent of cholera, displays a pentavalent binding domain that targets the oligosaccharide of ganglioside GM1 (GM1os) on the periphery of human abdominal epithelial cells. Here, we report the first GM1os-based CT inhibitor that matches the valency of the CT binding domain (CTB). This pentavalent inhibitor contains five GM1os moieties linked to a calix[5]arene sca...

In a recent ERP study of inhibitory control using the Stop-Signal Task [Pliszka, S., Liotti, M., Woldorff, M. (2000). Inhibitory control in children with attention-deficit/hyperactivity disorder: Event-related potentials identify the processing component and timing of an impaired right-frontal response-inhibition mechanism. Biological Psychiatry, 48, 238-246], we showed that in normal children ...

The inhibitory effects of six commonly used calcium channel blockers on three major cytochrome P-450 activities were examined and characterized in human liver microsomes. All six compounds reversibly inhibited CYP2D6 (bufuralol 1'-hydroxylation) and CYP2C9 (tolbutamide methyl hydroxylation) activities. The IC(50) values for the inhibition of CYP2D6 and CYP2C9 for nicardipine were 3 to 9 microM,...

A 59-year old woman was admitted at emergency for palpitation and dizziness. Medication history showed trimebutine 450 mg daily, because of meteorism, increased to 450 mg TID a week earlier. At admittance, sustained monomorphic ventricular tachycardia was interrupted by 100 mg intravenous lidocaine and a largely prolonged QTc (523 ± 12 ms) was seen. Discontinuation of trimebutine achieved norma...

The effects of methylenedioxyphenyl insecticide synergists on human health arise, not from their intrinsic toxicity which is relatively low, but from their dual effect on the oxidative detoxication or intoxication processes of the body. They are able to inhibit these reactions by two mechanisms. They are substrates for mixed function oxidation and, thus, compete with other xenobiotics for avail...