17 resultados para freeze fracture


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Background In human malaria, the naturally-acquired immune response can result in either the elimination of the parasite or a persistent response mediated by cytokines that leads to immunopathology. The cytokines are responsible for all the symptoms, pathological alterations and the outcome of the infection depends on the reciprocal regulation of the pro and anti-inflammatory cytokines. IL-10 and IFN-gamma are able to mediate this process and their production can be affected by single nucleotide polymorphisms (SNPs) on gene of these cytokines. In this study, the relationship between cytokine IL-10/IFN-gamma levels, parasitaemia, and their gene polymorphisms was examined and the participation of pro-inflammatory and regulatory balance during a natural immune response in Plasmodium vivax-infected individuals was observed. Methods The serum levels of the cytokines IL-4, IL-12, IFN-gamma and IL-10 from 132 patients were evaluated by indirect enzyme-linked immunosorbent assays (ELISA). The polymorphism at position +874 of the IFN-gamma gene was identified by allele-specific polymerase chain reaction (ASO-PCR) method, and the polymorphism at position -1082 of the IL-10 gene was analysed by PCR-RFLP (PCR-Restriction Fragment Length Polymorphism). Results The levels of a pro- (IFN-gamma) and an anti-inflammatory cytokine (IL-10) were significantly higher in P. vivax-infected individuals as compared to healthy controls. The IFN-gamma levels in primoinfected patients were significantly higher than in patients who had suffered only one and more than one previous episode. The mutant alleles of both IFN-gamma and IL-10 genes were more frequent than the wild allele. In the case of the IFNG+874 polymorphism (IFN-gamma) the frequencies of the mutant (A) and wild (T) alleles were 70.13% and 29.87%, respectively. Similar frequencies were recorded in IL-10-1082, with the mutant (A) allele returning a frequency of 70.78%, and the wild (G) allele a frequency of 29.22%. The frequencies of the alleles associated with reduced production of both IFN-gamma and IL-10 were high, but this effect was only observed in the production of IFN-gamma. Conclusions This study has shown evidence of reciprocal regulation of the levels of IL-10 and IFN-gamma cytokines in P. vivax malaria, which is not altered by the presence of polymorphism in the IL-10 gene.

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PURPOSE: To evaluate the in vitro fracture resistance of roots with glass-fiber and metal dowels with different designs. METHODS: Fifty-endodontically treated maxillary central incisors were embedded in acrylic resin. Ten of them received only the coronary preparation, and the remaining forty were embedded (except for 4mm of the cervical area) after removing the clinical crowns. Specimens were divided into five groups (n=10): control (teeth with only coronary preparation), cylindrical cast dowel, conical cast dowel, cylindrical glass-fiber dowel and conical glass-fiber dowel. Specimens were subjected to an increasing compressive load (N) until fracture. RESULTS: ANOVA indicated significant difference (P<.05) among the groups, and the Tukey-Kramer´s test identified these differences. The control group (867±243 N) presented the highest values and was statistically similar to cylindrical glass-fiber dowel group (711±180 N). There is no significant difference among the metal dowel cylindrical (435±245 N) or conical (585±164 N) group and conical glass-fiber dowel (453±112 N). Cylindrical glass-fiber dowel (711±180 N) and conical cast dowel and core (585±164 N) groups had intermediate values and did not differ from each other. CONCLUSIONS: Cylindrical glass fiber dowels represent a viable alternative to the cast-metal dowel cylindrical or conical. Cylindrical glass fiber dowels also increase endodontically treated incisors' resistance to fracture.