Toxoplasma gondii: The severity of toxoplasmic encephalitis in C57BL/6 mice is associated with increased ALCAM and VCAM-1 expression in the central nervous system and higher blood-brain barrier permeability

In order to investigate the differential ALCAM, ICAM-1 and VCAM-1 adhesion molecules mRNA expression and the blood-brain barrier (BBB) permeability in C57BL/6 and BALB/c mice in Toxoplasma gondii infection, animals were infected with ME-49 strain. It was observed higher ALCAM on day 9 and VCAM-1 expression on days 9 and 14 of infection in the central nervous system (CNS) of C57BL/6 compared to BALB/c mice. The expression of ICAM-1 was high and similar in the CNS of both lineages of infected mice. In addition, C57BL/6 presented higher BBB permeability and higher IFN-gamma and iNOS expression in the CNS compared to BALB/c mice. The CNS of C578L/6 mice presented elevated tissue pathology and parasitism. In conclusion, our data suggest that the higher adhesion molecules expression and higher BBB permeability contributed to the major inflammatory cell infiltration into the CNS of C57BL/6 mice that was not efficient to control the parasite. (C) 2010 Elsevier Inc. All rights reserved.

Increased Vascular Permeability, Angiogenesis and Wound Healing Induced by the Serum of Natural Latex of the Rubber Tree Hevea brasiliensis

Increases in vascular permeability and angiogenesis are crucial events to wound repair, tumoral growth and revascularization of tissues submitted to ischemia. An increased vascular permeability allows a variety of cytokines and growth factors to reach the damaged tissue. Nevertheless, the angiogenesis supply tissues with a wide variety of nutrients and is also important to metabolites clearance. It has been suggested that the natural latex from Hevea brasiliensis showed wound healing properties and angiogenic activity. Thus, the purpose of this work was to characterize its angiogenic activity and its effects on vascular permeability and wound healing. The serum fraction of the latex was separated from the rubber with reduction of the pH. The activity of the dialyzed serum fraction on the vascular permeability injected in subcutaneous tissue was assayed according Mile`s method. The angiogenic activity was determined using a chick embryo chorioallantoic membrane assay and its effects on the wound-healing process was determined by the rabbit ear dermal ulcer model. The serum fraction showed evident angiogenic effect and it was effective in enhancing vascular permeability. In dermal ulcers, this material significantly accelerated wound healing. Moreover, the serum fraction boiled and treated with proteases lost these activities. These results are in accordance with the enhancement of wound healing observed in clinical trials carried out with a biomembrane prepared with the same natural latex. Copyright (C) 2009 John Wiley & Sons, Ltd.

Reconstruction of mandibular segmental defects using the guided-bone regeneration technique with polylactide membranes and/or autogenous bone graft: A preliminary study on the influence of membrane permeability

Purpose: Bone maintenance after mandibular reconstruction with autogenous iliac crest may be disappointing due to extensive resorption in the long term. The potential of the guided-bone regeneration (GBR) technique to enhance the healing process in segmental defects lacks comprehensive scientific documentation. This study aimed to investigate the influence of polylactide membrane permeability on the fate of iliac bone graft (BG) used to treat mandibular segmental defects. Materials and Methods: Unilateral 10-mm-wide segmental defects were created through the mandibles of 34 mongrel dogs. All defects were mechanically stabilized, and the animals were divided into 6 treatment groups: control, BG alone, microporous membrane (poly L/DL-lactide 80/20%) (Mi); Mi plus BG; microporous laser-perforated (15 cm(2) ratio) membrane (Mip), and Mip plus BG. Calcein fluorochrome was injected intravenously at 3 months, and animal euthanasia was carried out at 6 months postoperatively. Results: Histomorphometry showed that BG protected by Mip was consistently related to larger amounts of bone compared with other groups (P <= .0001). No difference was found between defects treated with Mip alone and BG alone. Mi alone rendered the least bone area and reduced the amount of grafted bone to control levels. Data from bone labeling indicated that the bone formation process was incipient in the BG group at 3 months postoperatively regardless of whether or not it was covered by membrane. In contrast, GBR with Mip tended to enhance bone formation activity at 3 months. Conclusions: The use of Mip alone could be a useful alternative to BG. The combination of Mip membrane and BG efficiently delivered increased bone amounts in segmental defects compared with other treatment modalities. (C) 2008 American Association of Oral and Maxillofacial Surgeons.

INCREASED SARCOLEMMAL PERMEABILITY AS AN EARLY EVENT IN EXPERIMENTAL SEPTIC CARDIOMYOPATHY: A POTENTIAL ROLE FOR OXIDATIVE DAMAGE TO LIPIDS AND PROTEINS

This study describes increased sarcolemmal permeability and myofilamentar damage that occur together with lipid peroxidation and protein nitration in the myocardium in severe sepsis induced by cecal ligation and puncture. Male C57BL/6 mice were submitted to moderate and severe septic injury and sham operation. Using light and laser confocal microscopy, diffuse foci of myocytolysis associated with focal disruption of the actin/myosin contractile apparatus could be seen in hearts with severe septic injury. The myocardial expressions of the sarcomeric proteins myosin and actin were downregulated by both severe and moderate injuries. The detection of albumin staining in the cytoplasm of myocytes to evaluate sarcolemmal permeability provided evidence of severe and mild injury of the plasma membrane in hearts with severe and moderate septic injury, respectively. The administration of a superoxide scavenger caused marked reduction of sarcolemmal permeability, indicating the involvement of free radicals in its genesis. On electron microscopy, these changes were seen to correspond to spread blocks of a few myocytes with fragmentation and dissolution of myofibrils, intracellular edema, and, occasionally, rupture of the sarcolemma. In addition, oxidative damage to lipids, using anti-4-hydroxynonenal, an indicator of oxidative stress and disruption of plasma membrane lipids, and to proteins, using antinitrotyrosine, a stable biomarker of peroxynitrite-mediated protein nitration, was demonstrated. These findings make plausible the hypothesis that increased sarcolemmal permeability might be a primary event in myocardial injury in severe sepsis possibly due to oxidative damage to lipids and proteins that could precede phenotypic changes that characterize a septic cardiomyopathy.

Does a final rinse to remove smear layer interfere on dentin permeability of root canals?

Objective. The objective of this study was to assess the influence of different final irrigating solutions on dentin permeability and smear layer removal using the same specimens and relate the results obtained. Study design. Forty anterior human teeth were instrumented and divided into 4 groups (n = 10) at the final rinse step, according to the irrigant used: G I (control) - 1% NaOCl; G II - 17% EDTA; G III - 17% EDTAT; and G IV - Biopure MTAD. The canals were filled with 0.5% methylene blue and maintained in bottles for 48 hours. The roots were transversally split in coronal, middle, and apical fragments. The specimens were photographed and analyzed regarding dye penetration. The fragments were then axially split and prepared for SEM. The photomicrographs were analyzed and qualified by scores. Results. Only the EDTA-T group exhibited statistical difference in which the apical third had less dentin permeability (P < .05). When a decalcifying agent was used, smear layer was removed, which did not happen in the NaOCl group. Regarding smear layer removal, differences were found only in the EDTA group in which the apical third presented more smear layer (P < .05). No correlation was found for both studies (r = 0.4207). Conclusions. There was not an even relationship between the results from both studies, which inferes that higher or lower dentinal permeability does not necessarily correspond to a higher or lower amount of smear layer. The analysis of dentin permeability and smear layer removal was shown to be a feasible procedure using the same specimens. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 107: e47-e51)

Different air-water spray regulations affect the healing of Er,Cr:YSGG laser incisions

Surgeries performed with high-intensity laser devices may be improved with accurate protocols, including the air-water spray regulation. Thus, this study sought to investigate the healing process of wounds made on the dorsum of rat tongues using an Er,Cr:YSGG laser device with different air-water spray regulations. The incisions were made on the dorsum of Wistar rat tongues using an Er,Cr:YSGG laser with three different air-water spray regulations (100/0%, 50/50%, 11/7%). Scalpel incisions functioned as controls. The sacrifices occurred between 0 and 14 days after surgery. Morphological, histological, and immunohistochemical (fibronectin and type III collagen) analysis of the wounds were performed. The air-water spray regulation influenced wound healing and the inflammatory response, especially in the earlier stages. Incisions performed using the 100/0% air/water spray regulation had the worst results, expressing a greater amount of fibronectin and type III collagen. The 50/50% air/water spray regulation brought in a non-clear surgical field and poor laser interaction with the tissue. The 11/7% air/water spray regulation showed the best clinical results and less pronounced histological events. According to the results encountered, the air-water spray should be regulated to improve surgery.

Comparison of dentin root canal permeability and morphology after irradiation with Nd:YAG, Er:YAG, and diode lasers

The aim of this study was to compare the effects of Nd:YAG, Er:YAG, and diode lasers on the morphology and permeability of root canal walls. The three laser wavelengths mentioned interact differently with dentin and therefore it is possible that the permeability changes caused will determine different indications during endodontic treatment. Twenty-eight human single-rooted teeth were instrumented up to ISO 40 and divided into four groups: group C, control (GC), non-laser irradiated; group N (GN), irradiated with Nd:YAG laser; group E (GE), with Er:YAG laser and group D (GD) with diode laser. After that, the roots were filled with a 2% methylene blue dye, divided into two halves and then photographed. The images were analyzed using Image J software and the percentage of dye penetration in the cervical, middle, and apical root thirds were calculated. Additional scanning electron microscopy (SEM) analyses were also performed. The analysis of variance (ANOVA) showed significant permeability differences between all groups in the middle and cervical thirds (p < 0.05). The Tukey test showed that in the cervical third, GN presented means of dye penetration statistically significantly lower than all of the other groups. In the middle third, GE and GD showed statistically higher dye penetration means than GC and GN. SEM analysis showed melted surfaces for GN, clean wall surfaces with open dentinal tubules for GE, and mostly obliterated dentinal tubules for GD. Er:YAG (2,094 nm) laser and diode laser (808 nm) root canal irradiation increase dentinal permeability and Nd:YAG (1,064 nm) laser decreases dentin permeability, within the studied parameters.

Effect of the Combination of Sodium Hypochlorite and Chlorhexidine on Dentinal Permeability and Scanning Electron Microscopy Precipitate Observation

Introduction: This study compared the combined use of sodium hypochlorite (NaOCl) and chlorhexidine (CXH) with citric acid and CXH on dentinal permeability and precipitate formation. Methods: Thirty-four upper anterior teeth were prepared by rotary instrumentation and NaOCl. The root canal surfaces were conditioned for smear layer removal using 15% citric acid solution under ultrasonic activation and a final wash with distilled water. All teeth were dried, and 30 specimens were randomly divided into three equal groups as follows: positive control group (PC), no irrigation; 15% citric acid + 2% CHX group (CA + CHX); and 1% NaOCl + 2% CHX group (NaOCl + CHX). All roots were immersed in a 0.2% Rhodamine B solution for 24 hours. One-millimeter-thick slices from the cementum-enamel junction were scanned at 400 dpi and analyzed using the software ImageLab (LIDO-USP, Sao Paulo, Brazil) for the assessment of leakage in percentage. For scanning electron microscopy analysis, four teeth, irrigated for NaOCl + CHX samples, were split in half, and each third was evaluated at 1,000x and 5,000x (at the precipitate). Results: Using the analysis of variance test followed by the Bonferroni comparison method, no statistical differences between groups were found when analyzed at the cervical and medium thirds. At the apical third, differences between the PC and NaOCl + CHX (p<0.05) and CA + CHX and NaOCl + CHX could be seen (p < 0.05). Conclusion: The combination of 1% NaOCl and 2% CHX solutions results in the formation of a flocculate precipitate that acts as a chemical smear layer reducing the dentinal permeability in the apical third. (J Endod 2010;36:847-850)

Effect of oxalate desensitizers and dentin moisture during total-etch bonding

Purpose: To evaluate the effect of oxalate during total-etch bonding, under different dentin moisture conditions, over time. The null hypothesis tested was that microtensile bond strength (mu TBS) was not affected by oxalate treatment and dentin moisture during two evaluation periods. Methods: Extracted human third molars had their mid-coronal dentin exposed flat and polished with 600-grit SiC paper. The surfaces were etched with 35% phosphoric acid for 15 seconds, washed and blot dried. After etching, a 3% potassium oxalate gel was applied for 120 seconds, except for the control group (no desensitizer). The surface was then washed and left moist (Wet bonding) or air-dried for 30 seconds (Dry bonding). The surfaces were bonded with: (I) two 2-step etch-and-rinse adhesives: Single Bond (SB); Prime & Bond NT (PBNT) and (2) one 3-step etch-and-rinse adhesive: Scotchbond Multi Purpose (SBMP). Composite buildups were constructed incrementally with Tetric Ceram resin composite. Each increment was cured for 40 seconds. After storage in water for 24 hours or 1 year at 37 C, the specimens were prepared for mu TBS testing with a cross-sectional area of approximately 1 mm(2). They were then tested in tension in an Instron machine at 0.5 mm/minute. Data were analyzed by ANOVA and Student-Newman-Keuls at alpha = 0.05. Results: Application of potassium oxalate had no significant effect on the bond strengths of SBMP and PBNT, regardless of the surface moisture condition (P > 0.05). Conversely, reduced bond strengths were observed after oxalate treatment for SB in both moisture conditions, that being significantly lower when using a dry-bonding procedure (P < 0.05). Lower bond strength was obtained for PBNT when a dry-bonding technique was used, regardless of the oxalate treatment (P < 0.05). After aging the specimens for 1 year, bond strengths decreased. Smaller reductions were observed for SBMP, regardless of moisture conditions. For the WB technique, smaller reductions after 1 year were observed without oxalate treatment for SB and after oxalate treatment for PBNT. (Am J Dent 2010;23:137-141).