Biodistribution and biocompatibility of DMSA-stabilized maghemite magnetic nanoparticles in nonhuman primates (Cebus spp.).

AIM: This work represents the first reported investigation on the effects of magnetic nanoparticles (MNPs) in nonhuman primates. Biodistribution, biocompatibility and nanotoxicity of maghemite nanoparticles stabilized with dimercaptosuccinic acid (DMSA) were accessed. MATERIALS & METHODS: A control animal was used and three other animals were intravenously injected with DMSA-MNPs and euthanized 12 h, 30 and 90 days following administration. Extracted organs were processed by histological techniques. An additional animal was used to collect blood samples to complementarily assess biocompatibility 12 h, 7, 15, 30, 60 and 90 days after DMSA-MNP injection. RESULTS: DMSA-MNPs were preferentially addressed to the lungs, liver and kidneys. Hematological and serum biochemical results corroborated histological findings, supporting DMSA-MNP biocompatibility while preserving both hepatic and renal normal activity. CONCLUSION: DMSA-MNPs were preferentially distributed to the lung, liver and kidneys. Furthermore, DMSA-MNPs were considered biocompatible, supporting their application as a promising nanomaterial platform for future biomedical use.

The effect of DMSA-functionalized magnetic nanoparticles on transendothelial migration of monocytes in the murine lung via a beta2 integrin-dependent pathway.

Magnetic nanoparticles surface-functionalized with meso-2,3-dimercaptosuccinic acid (MNPs-DMSA) constitute an innovative and promising approach for tissue- and cell-targeted delivery of therapeutic drugs in the lung. Transendothelial migration of leukocytes in the lung is a side effect of endovenous administration of MNPs-DMSA. Using cytologic and phenotypic analysis of murine bronchoalveolar lavage cells, we identified monocytes/macrophages as the main subpopulation of leukocytes involved in this process. Moreover, ultrastructural analysis revealed the presence of nanoparticles inside of numerous macrophages from bronchoalveolar lavage. MNPs-DMSA at concentrations as high as 1 x 10(15) nanoparticles/mL had no toxic effects on macrophages, as evidenced by 3-(4, 5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay. Notably, MNPs-DMSA up-regulated the mRNA expression of E-, L- and P-selectin and macrophage-1 antigen in the murine lung. Upregulation of these cell adhesion molecules was associated with an increased concentration of tumor necrosis factor-alpha in lung. Finally, the critical relevance of the beta(2) integrin-dependent pathway in leukocyte transmigration elicited by MNPs-DMSA was demonstrated by use of knockout mice. Our results characterize mechanisms of the pro-inflammatory effects of MNPs-DMSA in the lung, and identify beta(2) integrin-targeted interventions as promising strategies to reduce pulmonary side effects of MNPs-DMSA during biomedical applications.

Expression patterns of cell adhesion molecules in mice's lung after administration of meso-2,3-dimercaptosuccinic acid-coated maghemite nanoparticles.

We studied the expression pattern of cell adhesion molecules associated to transendothelial migration of leukocytes in different lung's vascular compartments after administration of a magnetic fluid sample containing maghemite nanoparticles surface-coated with meso-2,3-dimercaptosuccinic acid. The analyses were conducted in mice 4 and 12 h after endovenous administration of the magnetic fluid in control mice. Firstly, the migratory activity of leukocytes after magnetic fluid surface-coated with meso-2,3-dimercaptosuccinic acid administration was confirmed using broncho-alveolar lavage and light microscopy. Then, the expression of cell adhesion molecules in the lung's vascular compartments was investigated by immunofluorescence microscopy of frozen sections, using antibodies against L-selectin, P-selectin, E-selectin, macrophage antigen-1, and leukocyte function associated antigen-1. L- and P-selectin showed similar pattern of expression in the pulmonary vasculature in animals treated with magnetic fluid and in the control group. In contrast, macrophage antigen-1 and leukocyte function associated antigen-1 were found in capillary only in animals treated with magnetic fluid surface-coated with meso-2,3-dimercaptosuccinic acid administration. In addition, after magnetic fluid administration E-selectin was found in post-capillary sites. Our findings demonstrated that magnetic fluid surface-coated with meso-2,3-dimercaptosuccinic acid administration exhibits modulation effects on expression patterns of E-selectin, macrophage antigen-1, and leukocyte function associated antigen-1 in the lung's vascular compartments. These findings are very important in a strategy to reduce the potential toxicity of magnetic fluid surface-coated with meso-2,3-dimercaptosuccinic acid administration for medical applications.

Cell-cycle deregulation induced by three different root canal sealers in vitro.

The aim of this study was to investigate the effects of 3 root canal sealers on the cell cycle of mouse fibroblasts (3T3 cell line). Freshly mixed root canal sealers (AH Plus, Endofill, and Sealer 26) were eluted for 24 h using cell culture medium. Antiproliferation activity of different eluate dilutions was determined by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay. Cell cycle was subsequently evaluated by flow cytometry. Differences were tested by analysis of variance with Tukey test (P < .05). Results showed that the root canal sealers inhibited cell growth in a dose-dependent manner. Antiproliferation activity of the root canal sealers was associated with cell-cycle deregulation. This event involved cell-cycle arrest in the S/G2/M phases and an increase of the sub-G1 population, which are consistent with both cytostatic and cytotoxic effects. This information may contribute to a better understanding of the toxicity mechanism displayed by root canal sealers currently used in clinical practice.

Multiple autoclave cycles affect the surface of rotary nickel-titanium files: an atomic force microscopy study.

The purpose of this study was to evaluate the surface of rotary nickel-titanium (Ni-Ti) files after multiple autoclave cycles. Two different types of rotary Ni-Ti (Greater Taper and ProFile) were attached to a glass base. After 1, 5, and 10 autoclave cycles the files were positioned in the atomic force microscope. The analyses were performed on 15 different points. The same files were used as control before any autoclave cycle. The following vertical topographic parameters were measured: arithmetic mean roughness, maximum height, and root mean square. The differences were tested by analysis of variance with Tukey test. All topographic parameters were higher for both Greater Taper and ProFile after 10 cycles compared with the control (P < .05). ProFile also showed higher topographic parameters after 5 cycles compared with the control (P < .05). The results indicated that multiple autoclave cycles increase the depth of surface irregularities located on rotary Ni-Ti files.

Periapical cyst repair after nonsurgical endodontic therapy: case report

O objetivo do presente estudo foi apresentar os procedimentos a serem considerados para o tratamento endodôntico não-cirúrgico de cistos periapicais. Um caso de cisto periapical associado ao incisivo lateral superior esquerdo é relatado. Após o tratamento endodôntico não-cirúrgico, o reparo da lesão foi observado radiograficamente em 24 meses. Diagnóstico diferencial, controle da infecção endodôntica, alargamento do forame apical e preenchimento da cavidade cística com pasta de hidróxido de cálcio foram procedimentos relevantes para a resolução do caso.

Atomic force microscopy study of stainless-steel and nickel-titanium files.

Atomic force microscopy (AFM) is a well established and documented tool for materials investigation. The aim of this study was to evaluate the topography of conventional stainless-steel files and both hand and rotary nickel-titanium (NiTi) files by using AFM. One endodontic file of each of the following was selected: stainless-steel K-file Dentsply, stainless-steel K-file Moyco, hand NiTi K-file Nitiflex, hand NiTi Greater Taper, rotary NiTi Greater Taper, and rotary NiTi Quantec. The analyses were performed on twenty different points located along a 3-mm section starting at the tip of each file. Root mean square (RMS) parameters for contact mode imaging microscopy variations were measured. The differences between RMS values were tested by ANOVA with Fisher's protected LSD test for multiple comparisons (p < 0.05). RMS of depth profile data was used to determine any statistically significant difference in vertical amplitude. According to results, all instruments showed topographic irregularities distributed on surface. Endodontic files manufactured by the same method and alloy demonstrated significant differences, whereas no significant differences were found for instruments produced by different alloys and methods (p < 0.05). The hand NiTi Greater Taper, rotary NiTi Greater Taper, and rotary NiTi Quantec showed greater values of vertical amplitude topography compared to K-Dentsply and Nitiflex files (p < 0.05). The AFM technique proved to be a valuable research tool in the investigation of endodontic files topography.

Structural effects of sodium hypochlorite solutions on gutta-percha cones: atomic force microscopy study.

Atomic force microscope (AFM) is a well-established methodology for structural characterization of materials. The purpose of this study was to investigate the effects of sodium hypochlorite (NaOCl) solutions on gutta-percha cone structure using AFM. Three standardized gutta-percha cones were cut 3 mm from the tip, attached to a glass base and immersed in 0.5, 2.5, or 5.25% NaOCl solutions. After 1 and 5 min the samples were positioned in the atomic force microscope. The analyses were performed on twelve different points (n=12) located between 1 and 2 mm from the tip after each period of immersion in NaOCl. Gutta-percha cone without any NaOCl treatment were used as control. Root mean square (RMS) parameters for contact mode imaging and force modulation microscopy variations were measured. The differences between RMS values were tested by ANOVA with Fisher's protected LSD test for multiple comparisons (p<0.05). Aggressive deteriorative effects on gutta-percha cone elasticity were observed for 5.25% NaOCl at 1 min when compared to the control (p<0.05). In addition, 2.5% and 5.25% NaOCl solutions caused topographic changes after 5 min when compared to the control (p<0.05). Conversely, 0.5% NaOCl solution did not cause any alteration on topography or elasticity of gutta-percha cone structure when compared to the control (p<0.05). Thus, 0.5% NaOCl solution is a safe alternative for rapid decontamination of gutta-percha cones.

Periapical cyst repair after nonsurgical endodontic therapy--case report.

This article presents the procedures that must be considered for periapical cyst repair after nonsurgical endodontic treatment. The case of a periapical cyst associated to the left maxillary lateral incisor is reported. Nonsurgical root canal therapy was performed and lesion healing was confirmed radiographically after 24 months. Differential diagnosis, endodontic infection control, apical foramen enlargement and filling of the cystic cavity with a calcium hydroxide paste were important procedures for case resolution.

Atomic force microscopy study of gutta-percha cone topography.

The aim of this study was to investigate the topography of the apical portion of 4 different commercially available standardized gutta-percha (GP) cones with atomic force microscopy (AFM). GP cones (Analytic, Dentsply, Tanari, and Endo Points) were cut 3 mm from the tip, attached in a glass base, and positioned in the AFM. Analyses were performed on 3 different regions of the GP sample and on 3 separate points of each region. Root mean square (RMS) parameters for topographic amplitudes and lateral force variations were calculated. The differences among GP brands were tested by ANOVA with a Fisher protected LSD test of multiple comparisons. According to our results, only Endo Points showed similar behavior between 2 parameters assessed (P <.05). All brands showed normally distributed deep depression in the apical portions, which are within the same scale as proteins and bacterial products that the cones should be blocking. AFM offers a powerful new tool to directly evaluate the characterization of GP cone surfaces.

Influence of the thickness of mineral trioxide aggregate on sealing ability of root-end fillings in vitro.

The purpose of this study was to compare the ability of different thicknesses of mineral trioxide aggregate (MTA) to prevent apical leakage through the use of a protein-dye complex with Coomassie Brilliant Blue G. Sixty-four teeth were divided into 4 groups, then filled with MTA to depths of 1, 2, 3, or 4 mm. Two teeth served as the positive controls. Another 2 teeth served as the negative controls. Root-filled teeth were mounted in an apparatus and then challenged with protein solution. The evaluation was conduced at 24-hour intervals for 60 days. The 1-mm-thick MTA was the least effective in preventing apical leakage (P <.05). No significance difference was found between 2- and 3-mm-thick MTA (P >.05). Four-millimeter-thick MTA was significantly more effective than the other thicknesses tested (P <.05). The results of this study suggest that the thickness of 4 mm is most adequate for the use of MTA as a root-end filling material.

Detecçäo de bacterioides forsythus em dez casos de infecçäo endodôntica pelo método da polymerase chain reaction / Polymerase chain reaction of bacteroides forsythus in ten cases of endodontic infection

Este trabalho tem como objetivo relatar dez casos de infecçäo endodôntica onde foi detectada a ocorrência da espécie bacteriana Bacteroides forsythus. Após coleta do material, a identificaçäo desta espécie foi realizada através do método da Reaçäo em Cadeia da Polimerase (Polymerase Chain Reaction - PCR). Nossos resultados indicaram que o B. forsythus pode ser um componente da microbiota presente em canais radiculares infectados, podendo estar associado à etiologia de lesöes perirradiculares