University of Extremadura

About: University of Extremadura is a education organization based out in Badajoz, Spain. It is known for research contribution in the topics: Population & Hyperspectral imaging. The organization has 7856 authors who have published 18299 publications receiving 396126 citations. The organization is also known as: Universidad de Extremadura.

Low daily 10-mg and 20-mg doses of fluvoxamine inhibit the metabolism of both caffeine (cytochrome P4501A2) and omeprazole (cytochrome P4502C19).

Abstract: Objectives Fluvoxamine is metabolized by the polymorphic cytochrome P450 (CYP) 2D6 and the smoking-inducible CYP1A2. Therapeutic doses of fluvoxamine inhibit both CYP1A2 and CYP2C19. In this study we used extensive metabolizers (EMs) and poor metabolizers (PMs) of debrisoquin (INN, debrisoquine) (CYP2D6) and two probes, caffeine (CYP1A2) and omeprazole (CYP2C19), to investigate whether nontherapeutic doses of fluvoxamine inhibit CYP1A2 but possibly not CYP2C19. Methods Single oral doses of 100 mg caffeine and 20 mg omeprazole were given separately to 5 EMs and 5 PMs of debrisoquin to assess the activity of CYP1A2 and CYP2C19, respectively. Initially, a single oral dose of fluvoxamine (25 mg to PMs and 50 mg to EMs) was given, followed by 1 week of daily administration of 25 mg × 2 to EMs and 25 mg × 1 to PMs. Caffeine (day 6) and omeprazole (day 7) were again administered at the steady state of fluvoxamine. Later the study protocol was repeated with a lower dose of fluvoxamine, 10 mg × 2 to EMs and 10 mg × 1 to PMs for 1 week. Concentrations of fluvoxamine, caffeine, omeprazole, and their metabolites were analyzed by HPLC methods in plasma and urine. Results The kinetics of fluvoxamine were not significantly different in EMs and PMs after a single oral dose of the drug. At the higher but not the lower steady-state dose of fluvoxamine, a significantly lower clearance in PMs compared with EMs was observed (geometric mean, 0.86 versus 1.4 L/h per kilogram; P < .05). At steady state, the 25 mg × 1 or × 2 fluvoxamine dose caused a pronounced inhibition of about 75% to 80% for both CYP1A2 and CYP2C19, whereas the inhibition after the lower 10 mg × 1 or × 2 dose was about 40% to 50%. The area under the plasma concentration-versus-time curve from 0 to 24 hours [AUC(0–24)] of caffeine increased 5-fold (P < .001) after the higher dose of fluvoxamine and 2-fold (P < .05) after the lower dose. The area under the plasma concentration-time curve from time zero to 8 hours [AUC(0–8)] ratio of 5-hydroxyomeprazole/omeprazole decreased 3.4-fold (P < .001) and 2.4-fold (P < .001), respectively. One EM subject had a very low oral clearance of fluvoxamine after both single and multiple dosing of the drug. This subject might have a deficient transporter protein in the gut, leading to an increased absorption of fluvoxamine. Conclusion No convincing evidence was found that CYP2D6 is an important enzyme for the disposition of fluvoxamine. Other factors seem to be more important. A nontherapeutic oral daily dose of fluvoxamine is sufficient to provide a marked inhibition of both caffeine (CYP1A2) and omeprazole (CYP2C19) metabolism. It was not possible to separate the inhibitory effects of fluvoxamine on these enzymes, even after such a low daily dose such as 10 mg × 1 or × 2 of fluvoxamine. Clinical Pharmacology & Therapeutics (2002) 71, 141–152; doi: 10.1067/mcp.2002.121788

A systematic review on marginal bone loss around short dental implants (<10 mm) for implant‐supported fixed prostheses

Abstract: Purpose This systematic review aimed to evaluate the effect of implant length on peri-implant marginal bone loss (MBL) and its associated influencing factors. Material and methods An electronic search of the PubMed and MEDLINE databases for relevant studies published in English from November 2006 to July 2012 was performed by one examiner (AM). Selected studies were randomized clinical trials, human experimental clinical trials or prospective studies (e.g., cohort as well as case series) with a clear aim of investigating marginal bone loss of short dental implants (<10 mm) supporting fixed prostheses. A random-effect meta-regression model was used to determine the relationship between the effect size mean MBL and the covariate “implant length.” Additionally, a subgroup analysis, by means of a random-effect one-way ANOVA model, comparing mean MBL values at different levels of each factor (“type of connection” and “type of prostheses”) was also performed. Results The meta-regression of mean MBL on the moderator “implant length” was found to be insignificant (P = 0.633). Therefore, it could not be concluded that implant length had an effect on peri-implant MBL. In addition, standardized differences in mean MBL on the subgroups short (<10 mm) and standard (≥10 mm) implants, as determined by the meta-analysis (random-effect model), were found to be statistically insignificant (P = 0.222). Conclusions Within limitations of the present systematic review, it could be concluded that short dental implants (<10 mm) had similar peri-implant MBL as standard implants (≥10 mm) for implant-supported fixed prostheses.

Gallic acid water ozonation using activated carbon

Abstract: The ozonation of gallic acid in water in the presence of activated carbon has been studied at pH 5. Hydrogen peroxide, ketomalonic and oxalic acids were identified as by-products. The process involves two main periods of reaction. The first period, up to complete disappearance of gallic acid, during which ozonation rates are slightly improved by the presence of activated carbon. The second one, during which activated carbon plays an important role as promoter, and total mineralization of the organic content of the water is achieved. The organic matter removal is due to the sum of contributions of ozone direct reactions and adsorption during the first period and to a free radical mechanism likely involving surface reactions of ozone and hydrogen peroxide on the carbon surface during the second period. There is a third transition period where by-products concentration reach maximum values and ozonation is likely due to both direct and free radical mechanisms involving ozone and adsorption. Discussion on the mechanism and kinetics of the process is also presented both for single ozonation and activated carbon ozonation.