Search results for "Mixed"
showing 10 items of 783 documents
Prediction of the mesiodistal size of unerupted canines and premolars for a group of Romanian children: a comparative study
2013
Objectives The aim of the present study was to develop an optimization method of multiple linear regression equation (MLRE), using a genetic algorithm to determine a set of coefficients that minimize the prediction error for the sum of permanent premolars and canine dimensions in a group of young people from a central area of Romania represented by a city called Sibiu. Material and Methods To test the proposed method, we used a multiple linear regression equation derived from the estimation method proposed by Mojers, to which we adjusted regression coefficients using the Breeder genetic algorithm. A total of 92 children were selected with complete permanent teeth with no clinically visible …
Distribution and induction of cytochrome P-450 and two cytochrome P-450-dependent monooxygenase activities in rat liver parenchymal cell subpopulatio…
1989
Liver parenchymal cells from the periportal and centrilobular zones differ in their morphological, biochemical and functional characteristics. In an effort to obtain fractions enriched in either periportal or centrilobular cells, isolated rat liver parenchymal cells were separated into five subpopulations by centrifugal elutriation. The mean diameters of the cells present in fractions I-V were 19.6, 21.1, 21.8, 22.7 and 23.5 micron, respectively. The content of cytochrome P-450 as well as benzphetamine N-demethylase and 7-ethoxyresorufin O-deethylase activities were higher in the larger parenchymal cells than in the smaller ones. After administration of phenobarbital the content of cytochro…
Induction of rat hepatic epoxide hydratase by dietary antioxidants
1979
Abstract Supplementation of rat diet with butylated hydroxytoluene (BHT), butylated hydroxyanisole, or ethoxyquin resulted in increased liver epoxide hydratase activity. The increase was obvious at 0.1% and amounted to 200–400% at 0.5%. Increased activity was accompanied by increased proportion of the epoxide hydratase band in SDS polyacrylamide gels, indicating induction of the enzyme. Ethoxycoumarin deethylase activity and cytochrome b5 concentrations were moderately elevated while cytochrome P-450 concentrations and aryl hydrocarbon hydroxylase activity remained at control levels. Preferential inhibition of monooxygenase activity by metyrapone and not 7,8-benzoflavone, as well as increas…
Regio- and stereoselective regulation of monooxygenase activities by isoenzyme-selective phosphorylation of cytochrome P450.
1989
The phosphorylation of the two major phenobarbital-inducible cytochrome P450 isoenzymes IIB1 and IIB2 was increased in hepatocytes by the action of the membrane permeating cAMP derivatives N6-dibutyryl-cAMP and 8-thiomethyl-cAMP. Under these conditions the dealkylation of 7-pentoxyresorufin, a selective substrate of cytochrome P450IIB1 and P450IIB2 was markedly reduced. 16 beta-Hydroxylation of testosterone which is catalyzed specifically only by cytochrome P450IIB1 and IIB2 was strongly reduced; for 16 alpha-hydroxylation which is also catalyzed by cytochrome P450IIB1 and IIB2 but additionally by 3 further cytochrome P450 isoenzymes, this reduction was less pronounced; for the oxidation of…
Oxidation of tienilic acid by human yeast-expressed cytochromes P-450 2C8, 2C9, 2C18 and 2C19. Evidence that this drug is a mechanism-based inhibitor…
1996
Oxidation of tienilic acid by human cytochromes P-450 (CYP) 2C9, 2C18, 2C8 and 2C19 was studied using recombinant enzymes expressed in yeast. CYP 2C9 was the best catalyst for 5-hydroxylation of tienilic acid (K(m) = 5 +/- 1 microM, kcat = 1.7 +/- 0.2 min-1), 30-fold more potent in terms of kcat/K(m) than CYP 2C18 (K(m) = 150 +/- 15 microM, kcat = 1.8 +/- 0.2 min-1) and 300-fold more potent than CYP 2C8 (K(m) = 145 +/- 15 microM, kcat = 0.2 +/- 0.1 min-1). CYP 2C19 was unable to catalyze this hydroxylation under our experimental conditions. During this study, a marked effect of the ionic strength on the activities (hydroxylations of tienilic acid and tolbutamide) of these cytochromes P-450 …
Ethoxyquin as an inducer and inhibitor of phenobarbital-type cytochrome P-450 in rat liver microsomes.
1977
Abstract The effect of ethoxyquin in vivo and in vitro on drug metabolism in rat liver microsomes was studied. In feeding experiments, a threshold dose of induction was found at 0.05% ethoxyquin for 14 days. At 0.5% ethoxyquin, relative liver weight, cytochrome P-450 content, cytochrome b5 content, ethylmorphine demethylation, and ethoxycoumarin deethylation were increased by a factor of 1.5 to 2. Aryl hydrocarbon hydroxylase activity was, however, not induced but even decreased by 0.5% ethoxyquin in food. Induction of epoxide hydratase was marked, amounting to 400% of control after 0.5% ethoxyquin. The induced enzyme was similar to the phenobarbital-inducible cytochrome P-450 in its CO spe…
Molecular cloning and characterization of the cDNA encoding the rat liver gamma-butyrobetaine hydroxylase
1999
Carnitine biosynthesis from lysine and methionine involves five enzymatic reactions. gamma-butyrobetaine hydroxylase (BBH; EC 1.14. 11.1) is the last enzyme of this pathway. It catalyzes the reaction of hydroxylation of gamma-butyrobetaine to carnitine. The cDNA encoding this enzyme has been isolated and characterized. The cDNA contained an open reading frame of 1161 bp encoding a protein of 387 amino acids with a deduced molecular weight of 44.5 kDa. The sequence of the cDNA showed an important homology with the human cDNA recently isolated. Northern analysis showed gamma-butyrobetaine hydroxylase expression in the liver and in some extend in the testis and the epididymis. During this stud…
Surface electromyographic evaluation of jaw muscles in children with unilateral crossbite and lateral shift in the early mixed dentition. Sexual dimo…
2011
Objectives: To examine the activity of jaw muscles at rest and during maximal voluntary clenching (MVC) in children with unilateral posterior crossbite (UPXB) and functional lateral shift in the early mixed dentition and to evaluate sex differences. Material and Methods: The sample included 30 children (15 males, 15 females) aged 6 to 10 years old, with UPXB and functional mandibular lateral shift (≥1.5 mm) in the early mixed dentition. sEMG activity coming from the muscle areas (anterior temporalis [AT], posterior temporalis [PT], masseter [MA] and suprahyoid [SH]) were obtained from both the crossbite (XB) and noncrossbite (NONXB) sides at mandibular rest position. sEMG acti-vity of the b…
Measurement of substrate-induced oxygen uptake during microsomal drug oxidation using a gold micro-electrode.
1975
1. A resin-coated gold micro-electrode has been used for polarographic determination of oxygen concentration in liver microsomal suspensions from phenobarbital-pretreated rats. 2. The rate of oxygen uptake on addition of an NADPH-regenerating system and the rate after addition of various substrates of the mixed function oxidase system were measured. The rate of oxygen uptake was faster in the presence of substrate than in the presence of NADPH alone. 3. Kinetic constants (Km and V max) for biphenyl, hexobarbital, ethylmorphine, naphthalene and SKF 525-A measured by this technique compare favourably with those obtained either by measurements of NADPH oxidation, or chemical measurements of su…
Stress in School. Some Empirical Hints on the Circadian Cortisol Rhythm of Children in Outdoor and Indoor Classes
2017
This prospective longitudinal survey compared the stress levels of students taught using an outdoor curriculum in a forest, with children in a normal school setting. We were especially interested in the effect outdoor teaching might have on the children’s normal diurnal cortisol rhythm. 48 children (mean age = 11.23; standard deviation (SD) = 0.46) were enrolled, with 37 in the intervention group (IG), and 11 in the control group (CG). The intervention consisted of one full school day per week in the forest over the school year. Stress levels were measured in cortisol with three samples of saliva per day. Furthermore, the data allowed for statistical control of physical activity (PA) values…