Role of inflammatory mediators in priming, activation, and deformability of bovine neutrophils

Objective-To determine the capacity of inflammatory mediators tumor necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8), platelet-activating factor (PAF), lipopolysaccharide (LPS), and leukotoxin to prime, activate, or alter deformability of adult bovine neutrophils.Sample Population-Blood collected from 5 healthy adult Holstein cows.Procedure-Isolated neutrophils or whole brood was incubated with TNF-alpha, IL-8, PAF, LPS, or leukotoxin, and neutrophil chemiluminescence, degranulation, deformability, shape change, CD11b expression, and size distribution was measured.Results-incubation with TNF-alpha, IL-8; PAF, and IFS primed neutrophils for oxygen radical release but caused minimal oxygen radical release by themselves. None of the inflammatory mediators induced degranulation. Incubation with TNF-alpha and PAF resulted in a decrease in neutrophil deformability and induced shape change in neutrophils. incubation with PAF consistently resulted in an increase in neutrophil size as measured by use of flow cytometry. Only IL-8 caused an increase in expression of CD11b by neutrophils.Conclusions and Clinical Relevance-Inflammatory mediators tested had minimal effects on neutrophil oxygen radical production or degranulation but did prime neutrophils for oxygen radical production. Incubation with PAF and TNF-alpha caused a decrease in neutrophil deformability and altered neutrophil shape and size. Results of our study indicate that PAF- and TNF-alpha-induced changes in neutrophil deformability and size may cause integrin- and setectin-independent trapping of neutrophils in the lungs of cattle with pneumonic pasteurellosis.

Polymerization shrinkage: effects of boundary conditions and filling technique of resin composite restorations

Objective: To evaluate the linear polymerization shrinkage (LPS) and the effect of polymerization shrinkage of a resin composite and resin-dentin bond strength under different boundary conditions and filling techniques.Methods: Two cavities (4 x 4 x 2 MM) were prepared in bovine incisors (n = 30). The teeth were divided into three groups, according to boundary conditions: In group TE, the total-etch technique was used. In group EE, only enamel was conditioned, and in group NE, none of the watts of the cavities were conditioned. A two-step adhesive system was applied to all cavities. The resin composite was inserted in one (B) or three increments (1), and tight-cured with 600 mW/cm(2) (80 s). The LPS (%) was measured in the top-bottom direction, by placing a probe in contact with resin composite during curing. Enamel and total mean gap widths were measured (400 x) in three slices obtained after sectioning the restorations. Then, the slices were sectioned again, either to obtain sticks from the adhesive interface from the bottom of the cavity or to obtain resin composite sticks (0.8 mm(2)) to be tested for tensile strength (Kratos machine, 0.5 mm/min). The data was subjected to a two-way repeated measures ANOVA and Tukey's test for comparison of the means (alpha = 0.05).Results: the highest percentage of LPS was found for the TE when bulk fitted, and the lowest percentage of LPS was found in the Hand NE when incrementally fitted. The resin dentin bond strength was higher and the total mean gap width was tower for TE group; no significant effect was detected for the main factor fitting techniques. No difference was detected for the tensile strength of resin composite among the experimental groups.Conclusions: the filling technique is not able to minimize effects of the polymerization shrinkage, and bonding to the cavity watts is necessary to assure reduced mean gap width and high bond strength values. (C) 2004 Elsevier Ltd. All rights reserved.

Comparative ablation rate from a Er : YAG laser on enamel and dentin of primary and permanent teeth

This study was conducted to analyze the ablation rate and micromorphological aspects of microcavities in enamel and dentin of primary and permanent teeth using a Er:YAG laser system. Micromorphological evaluation has been performed in terms of permanent teeth; however, little information about Er: YAG laser interaction with primary teeth can be found in the literature. Because children have been the most beneficiary patients with laser therapy in our offices, it is extremely necessary to compare the effects of this kind of laser system on the enamel and dentin of permanent and primary teeth. In this study, we used eleven intact primary anterior exfoliated teeth and six extracted permanent molar teeth. We used a commercial laser system: a Er: YAG Twin Light laser system (Fotona Medical Lasers, Slovenia) at 2940 nm, changing average energy levels per pulse ( 100, 200, 300, and 400 mJ) producing 48 microcavities in enamel and dentin of primary and permanent teeth. Primary teeth are more easily ablated than are permanent teeth, when related to enamel or dentin. However, while this laser system is capable of slowly revealing the enamel's microstructure, in dentin only the lowest laser energies permit this kind of observation, more easily decomposing the original tissue aspect, when related to primary or permanent teeth. Statistically, the only different factor at the 5% level was an energy per pulse of 400 mJ, confirming the results found in SEM. Our results showed that dentin in both primary and permanent teeth is less resistant to Er: YAG laser ablation; this fact is easily observed under SEM observation and through the ablation rate evaluation.