39 research outputs found
Migration rate and genetic diversity of two Drosophila maculifrons (Duda, 1927) populations from Highland Araucaria Forest Fragments in Southern Brazil
Development of a competency model for placement and verification of nasogastric and nasoenteric feeding tubes for adult hospitalized patients
Nasogastric/nasoenteric (NG/NE) feeding tube placements are associated with adverse events and, without proper training, can lead to devastating and significant patient harm related to misplacement. Safe feeding tube placement practices and verification are critical. There are many procedures and techniques for placement and verification; this paper provides an overview and update of techniques to guide practitioners in making clinical decisions. Regardless of placement technique and verification practices employed, it is essential that training and competency are maintained and documented for all clinicians placing NG/NE feeding tubes. This paper has been approved by the American Society for Parenteral and Enteral Nutrition (ASPEN) Board of Directors.Published versio
Arthropod venom Hyaluronidases: biochemical properties and potential applications in medicine and biotechnology
Modeling the IR Spectra of Aqueous Metal Carboxylate Complexes: Correlation between Bonding Geometry and Stretching Mode Wavenumber Shifts
A widely used principle is that shifts in the wavenumber of carboxylate stretching modes upon bonding with a metal center can be used to infer if the geometry of the bonding is monodentate or bidentate. We have tested this principle with ab initio modeling for aqueous metal carboxylate complexes and have shown that it does indeed hold. Modeling of the bonding of acetate and formate in aqueous solution to a range of cations was used to predict the infrared spectra of the metal-carboxylate complexes, and the wavenumbers of the symmetric and antisymmetric vibrational modes are reported. Furthermore, we have shown that these shifts in wavenumber occur primarily due to how bonding with the metal changes the carboxylate C-O bond lengths and O-C-O angle
The effect of the use of 2% chlorhexidine gel in post-space preparation on carbon fiber post retention
Objective. Evaluate the bond strength of a resin cement used to lute carbon fiber posts, when drills and 4 different substances were used for the post-space preparation. Study design. Forty human canines were treated endodontically, and had a 10-mm length post space preparation. Four different substances were used with the drills: G1 - saline, G2 - 2% chlorhexidine gel, G3 - EDTA/NaOCl, and G4 - xylene. Carbon fiber posts (C-Post) were cemented with Allbond2 and Hi-X. Then, the posts were dislodged by tensional forces. Results. The groups of chlrohexidine (G2) and xylene (G4) obtained superior average values of bond strength at the 5% significance level (Parametric analyzes ANOVA/Tukey/Scheffe) differing statistically from the other groups. There was no statistical significant difference between groups 2 and 4. Conclusion. Xylene and chlorhexidine gel are good substances for the post-space preparation but the second has the advantage of antimicrobial activity and low toxicity.99337237
Evaluation of cytotoxicity and up-regulation of gelatinases in human fibroblast cells by four root canal sealers
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Silva EJNL, Accorsi-Mendonc, a T, Almeida JFA, Ferraz CCR, Gomes BPFA, Zaia AA. Evaluation of cytotoxicity and up-regulation of gelatinases in human fibroblast cells by four root canal sealers. International Endodontic Journal, 45, 49-56, 2012. Aim To investigate the effects of root canal sealers on the cytotoxicity and gelatinolytic activity of matrix metalloproteinases (MMPs) in human fibroblasts. Methodology Human fibroblasts (MRC5, 3 x 105 cells per well) were incubated directly or indirectly with AH Plus, Endomethasone N, Pulp Canal Sealer EWT or Sealapex for 30 min, 1, 4 or 24 h (time-points). The cytotoxicity of all root canal sealers was determined by counting viable cells using the trypan blue exclusion assay. Supernatants of cell cultures incubated with root sealers directly or indirectly were collected after each time-point to determine the levels of MMP-2 and MMP-9 gelatinolytic activity by gelatin zymography. Data were analysed using anova and the Tukeys tests. Results Cells secreted MMP-2 after periods of 4 and 24 h; however, there were no significant differences between the sealers. Secretion of gelatinases was elevated by root canal sealers in direct contact with the cell monolayer when compared to indirect contact (P < 0.05). At the time-points tested, no gelatinolytic activity could be detected in the control group without the sealers. The cytotoxicity results revealed that all sealers were cytotoxic in both contact forms. Sealapex had the lowest cytotoxicity and AH Plus the most cytotoxicity. Conclusions All root canal sealers induced the expression of MMP-2 in MRC5 fibroblasts. AH Plus had the highest cytotoxicity amongst the tested sealers, but all were associated with cytotoxic effects.4514956Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2009/12160-7
Degradation of trans-polyisoprene over time following the analysis of root fillings removed during conventional retreatment
Aim: To evaluate in vivo degradation of root filling materials over time. Methodology: Thirty-six root filled teeth with or without periapical lesions were selected. Teeth with poor coronal restoration were not included. The teeth had been root filled 3-30 years previous and were scheduled for conventional retreatment. The association of root canal treatment, age, periapical lesion and root filling degradation was investigated. The filling material was removed from the root canal using files and no solvent. Trans-1,4-polyisoprene was isolated through solubilization of root filling remnants in chloroform followed by filtration and centrifugation. Gel permeation chromatography (GPC) and infrared spectroscopy (FT-IR) were utilized to study the occurrence and degree of degradation. The GPC and FT-IR data were collected for each sample and analysed statistically using the Kruskal-Wallis test. Results: Degradation of trans-1,4-polyisoprene was a slow process. The process was identified as an oxidation reaction through the production of carboxyl and hydroxyl groups. Compared with the control group, significant molar mass decrease was noted after 15 years (P = 0.0146) in teeth with no periapical lesions. However, in teeth associated with periapical lesions the number of years for significant degradation was reduced to 5 (P = 0.0009). Conclusion: Polyisoprene degrades inside root canals as an oxidative process. The presence of periapical lesions was associated with a more rapid onset of degradation.401253