Pediatric glioblastoma cell line shows different patterns of expression of transmembrane ABC transporters after in vitro exposure to vinblastine

Resistance to drug is a major cause of treatment failure in pediatric brain cancer. The multidrug resistance (MDR) phenotype can be mediated by the superfamily of adenosine triphosphate-binding cassette (ABC) transporters. The dynamics of expression of the MDR genes after exposure to chemotherapy, especially the comparison between pediatric brain tumors of different histology, is poorly described. To compare the expression profiles of the multidrug resistance genes ABCB1, ABCC1, and ABCG2 in different neuroepithelial pediatric brain tumor cell lines prior and following short-term culture with vinblastine. Immortalized lineages from pilocytic astrocytoma (R286), anaplasic astrocytoma (UW467), glioblastoma (SF188), and medulloblastoma (UW3) were exposed to vinblastine sulphate at different schedules (10 and 60 nM for 24 and 72 h). Relative amounts of mRNA expression were analyzed by real-time quantitative polymerase chain reaction. Protein expression was assessed by immunohistochemistry for ABCB1, ABCC1, and ABCG2. mRNA expression of ABCB1 increased together with augmenting concentration and time of exposure to vinblastine for R286, UW467, and UW3 cell lines. Interestingly, ABCB1 levels of expression diminished in SF188. Following chemotherapy, mRNA expression of ABCC1 decreased in all cell lines other than glioblastoma. ABCG2 expression was influenced by vinblastine only for UW3. The mRNA levels showed consistent association to protein expression in the selected sets of cell lines analyzed. The pediatric glioblastoma cell line SF188 shows different pattern of expression of multidrug resistance genes when exposed to vinblastine. These preliminary findings may be useful in determining novel strategies of treatment for neuroepithelial pediatric brain tumors.

Cross-mating experiments with geographically different populations of Amblyomma cajennense (Acari: Ixodidae)

The present study evaluated the reproductive compatibility of the crosses between adult ticks of the following three geographically different populations of Amblyomma cajennense: State of So Paulo (SP), southeastern Brazil; State of Rondnia (RO), northern Brazil; and Colombia (CO). In addition, crosses between A. cajennense ticks from Argentina (AR) and SP ticks were also performed. The Argentinean population (AR) was compatible with SP because their crosses resulted in high % egg hatching (mean values ranging from 71.5 to 93.5%), similarly to all homologous (intrapopulational) crosses. In contrast, the tick populations SP, RO, and CO were shown to be incompatible with each other, since their heterologous (interpopulational) crosses always resulted in very low % egg hatching (range: 0-5%). The F(1) larval offspring derived from some of these females that yielded 5% egg hatching were reared until the F(1) adult stage. In all cases, only adult females molted from engorged nymphs. These F(1) females were likely to be a product of thelytokous parthenogenesis of the SP, RO, and CO females that were used in the heterologous crosses. Reproductive incompatibility is not expected to occur between different populations of a single species. Thus, our results suggest that the taxon A. cajennense might be represented by a complex of different species, whereas SP and AR ticks might represent a single species. Further populational genetic studies, coupled with extensive morphological analyses, are needed to clarify and determine a possible complex of valid species that might have been classified under the taxon A. cajennense.

Effects of gonadotropin-exposed medium with high concentrations of progesterone and estradiol-17 beta on in vitro maturation of canine oocytes

During the process of maturation in the oviduct, canine oocytes in the germinal vesicle stage are exposed to decreasing levels of estradiol-17 beta and increasing levels of progesterone. However, hormone concentrations in the microenvironments in which they act are higher than serum concentrations. Therefore, the aim of the present study was to compare the meiotic competence of canine oocytes harvested from anestrous bitches in culture medium containing high concentrations (20 mu g ml(-1)) of estradiol-17 beta and/or progesterone in association to gonadotropins (luteinizing hormone and follicle-stimulating hormone) using three different maturation periods (48, 72, and 96 h). Oocytes were cultured in tissue culture medium (TCM-199) and arranged in four experimental groups: group control, group E2 (estradiol-17 beta), group P4 (progesterone), and group E2 + P4. Regardless of the maturation period, groups P4 and E2 + P4 presented statistically higher rate of germinal vesicle breakdown oocytes compared to the group control and group E2. There were no significant differences among groups on germinal vesicle, metaphase I, metaphase II, and degenerated or unidentifiable oocytes rates. The mean percentage of metaphase II oocytes was higher at 96 h when compared to 72 h. Results of the present research indicate no influence of estradiol-17 beta supplementation, unless in association with progesterone. There is an evidence of the positive effect of progesterone on germinal vesicle breakdown. Results also showed that extended periods of in vitro maturation affect positively maturation rates to metaphase II of low competent oocytes harvested from anestrous bitches, independent of the maturation media. In conclusion, high concentrations of steroids, especially progesterone, have positive effect on in vitro oocyte maturation when the oocytes are derived from the anestrous status.

Radiopacity of Portland Cement Associated With Different Radiopacifying Agents

This study evaluated the radiopacity of Portland cement associated with the following radiopacifying agents: bismuth oxide, zinc oxide, lead oxide, bismuth subnitrate, bismuth carbonate, barium sulfate, iodoform, calcium tungstate, and zirconium oxide. A ratio of 20% radiopacifier and 80% white Portland cement by weight was used for analysis. Pure Portland cement and dentin served as controls. Cement/radiopacifier and dentin disc-shaped specimens were fabricated, and radiopacity testing was performed according to the ISO 6876/2001 standard for dental root sealing materials. Using Insight occlusal films, the specimens were radiographed near to a graduated aluminum stepwedge varying from 2 to 16 mm in thickness. The radiographs were digitized and radiopacity compared with the aluminum stepwedge using Digora software (Orion Corporation Soredex, Helsinki, Finland). The radiographic density data were converted into mmAl and analyzed statistically by analysis of variance and Tukey-Kramer test (alpha = 0.05). The radiopacity of pure Portland cement was significantly lower (p < 0.05) than that of dentin, whereas all cement/radiopacifier mixtures were significantly more radiopaque than dentin and Portland cement alone (p < 0.05). Portland cement/bismuth oxide and Portland cement/lead oxide presented the highest radiopacity values and differed significantly from the other materials (p < 0.05), whereas Portland cement/zinc oxide presented the lowest radiopacity values of all mixtures (p < 0.05). All tested substances presented higher radiopacity than that of dentin and may potentially be added to the Portland cement as radiopacifying agents. However, the possible interference of the radiopacifiers with the setting chemistry, biocompatibility, and physical properties of the Portland cement should be further investigated before any clinical recommendation can be done. (J Endod 2009,35:737-740)

Presence of arsenic in different types of MTA and white and gray Portland cement

Objective. The presence of arsenic in various types of mineral trioxide aggregate (MTA) and Portland cements were evaluated to verify if they comply with the ISO-recommended limit for water-based cements of 2 mg arsenic/kg material. Study design. An amount of 5 mL of hydrochloric acid was added to 2 g each of MTA and Portland cement to be analyzed. After 15 minutes, the material was filtered and the volume of supernatant was diluted with reagent-grade water up to 40 mL. Atomic absorption spectrophotometry readings were performed in triplicate. Results. The following mean values were obtained: CPM (Egeo, Buenos Aires, Argentina) 11.06 mg/kg; CPM sealer (Egeo) 10.30 mg/kg; MTA- Obtura (Angelus, Londrina, PR, Brazil) 0.39 mg/kg; Experimental MTA: 10.30 mg/kg; White MTA- Angelus (Angelus) 1.03 mg/kg; Gray MTA- Angelus (Angelus) 5.91 mg/kg; ProRoot-MTA (Dentsply/Tulsa Dental Specialties, Tulsa, OK) 5.25 mg/kg; Gray Portland cement (Votorantim Cimentos, Cubatao, SP, Brazil): 34.27 mg/kg; and White Portland cement (Cimento Rio Branco, Rio de Janeiro, RJ, Brazil) 0.52 mg/kg. Conclusion. All tested materials presented arsenic in their composition. The form of arsenic was not analyzed nor the toxicity of the arsenic found. Only MTA- Obtura, White MTA- Angelus, and White Portland cement presented arsenic levels below the limit set in the ISO 9917-1 standard. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008; 106: 909-913)

Stability of wet versus dry bonding with different solvent-based adhesives

Objective. To evaluate the effects of surface moisture (wet or dry) and storage (24h or 3 months) on the microtensile bond strength (BS) of resin/dentin bonds mediated by two water/ethanol based adhesives Single Bond, 3M-ESPE, (SB) and Opti Bond Solo Plus, Kerr, (OB), and two acetone-based adhesives, One Step, Bisco, (OS) and Prime&Bond NT, Caulk/Dentsply, (PB). Materials and methods. Flat dentin surfaces were polished with 600-grit SiC paper, etched with 35% phosphoric acid for 15 s and rinsed for 20 s. Half the surface was maintained moist and the other half was air-dried for 30 s. Each adhesive was applied simultaneously to both halves, left undisturbed for 30 s and light-cured. Four-mm resin build-ups were constructed incrementally. After storage in water at 37 degrees C for 24h, slabs were produced by transversal sectioning and trimmed to an hourglass shape (0.8 mm 2). Half of the specimens were tested in tension at 0.6 mm/min immediately after trimming and the other half after 3 months of water storage. Data were analyzed by two-way ANOVA and SNK for each material. Results. Both moisture and storage affected BS to dentin, and was material- dependent. Dry, bonding affected mostly the acetone-based adhesives. Larger reductions in bond strength were associated with dry bonding after 3 months of water storage. Significance. Wet bonding resulted in more stable bonds over 3 months of water storage for most of the materials tested. (C) 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Influence of the menstrual cycle on the pressure pain threshold of masticatory muscles in patients with masticatory myofascial pain

Objective. The aim of this study was to investigate the influence of the menstrual cycle and oral contraceptive (OC) intake on the pressure pain threshold (PPT) of masticatory muscles in patients with masticatory myofascial pain (MFP). Study design. The sample was composed of 36 women, divided into 4 groups, according to the presence of MFP and the intake of OC (15 patients had MFP [7 taking OC] and 21 were pain-free controls [8 taking OC]). The algometer-based PPT of masseter and temporalis, and the record of subjective pain by visual analog scale (VAS) were determined during 2 consecutives menstrual cycles at 4 phases (menstrual, follicular, periovulatory, and luteal). A 3-way ANOVA for repeated measurements, Kruskal-Wallis, Friedman, and Dunn tests, with a 5% significant level analyzed the data. Results. PPT was significantly lower in MFP patients when compared with controls throughout the experiment (P < .001). The menstrual phases did not influence PPT (P > .05), while the intake of OC seems to raise PPT levels for the left temporalis (P = .01) and right masseter (P = .04). VAS was, in general, higher at the menstrual phase Conclusions. Different phases of the menstrual cycle have no influence on PPT values, regardless of the presence of a previous condition, as masticatory myofascial pain, while the intake of OC is associated with decreased levels of reported pain.

Bacterial leakage evaluation of root canals filled with different endodontic sealers

Objective. The objective of this study was to evaluate the sealing ability of AH Plus, Epiphany, Acroseal, Endofill, and Polifil after active lateral condensation technique, by using a bacterial test, during 64 days. Study design. One hundred bovine incisors were cleaned and shaped; then they were filled with the endodontic sealers and adapted into a microcentrifuge tube. The setup root/microcentrifuge tube was added to glass flasks containing Brain Heart Infusion broth. A culture of Enterococcus faecalis was inserted into the upper chamber of each assembly. Daily leakage was evaluated through the broth turbidity. Results. The results were submitted to statistical analysis (Kaplan-Meier method, Kruskal-Wallis and Dunn tests). Conclusions. AH Plus and Endofill had the worst sealing ability when compared with Polifil, which showed the least leakage. Acroseal and Epiphany showed a tendency toward having an intermediate behavior; however, there was no significant difference among Acroseal, Epiphany, and the other sealers. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 108: e56-e60)

Gingival crevicular fluid levels of MMP-8, MMP-9, TIMP-2, and MPO decrease after periodontal therapy

P>Background This study aimed at comparing the levels of matrix metalloproteinase (MMP)-8, tissue Inhibitor of MMPs (TIMP)-1 and TIMP-2, Myeloperoxidase (MPO), and MMP-9 in the gingival crevicular fluid (GCF) of chronic periodontitis (CP) patients and controls at baseline and 3 months after non-surgical therapy. Materials and Methods GCF was collected from one site of 15 control subjects and 27 CP patients. MMP-8, MMP-9, TIMP-1, and TIMP-2 were determined by Enzyme-linked immunoabsorbent assay; different forms of MMP-9, by gelatin zymography; and MPO, colorimetrically. Results At baseline, higher levels of MMP-8, TIMP-2, MPO, and the 87 kDa-MMP-9 were found in patients compared with controls (p < 0.001), and these molecules decreased after therapy (p < 0.03). There were no differences between the groups with respect to the higher molecular forms of MMP-9 (180, 130, 92 kDa) or total MMP-9 at baseline. No differences were observed in TIMP-1 levels. In controls, decreased levels of TIMP-2 and the higher molecular forms of MMP-9 (180, 130, 92 kDa) were found 3 months after therapy compared with baseline (p < 0.01). Conclusions Higher levels of MMP-8, TIMP-2, MPO, and 87 kDa MMP-9 were found in the GCF of patients compared with controls, and these markers decreased 3 months after periodontal therapy.

Mice with genetic deletion of the heparin-binding growth factor midkine exhibit early preclinical features of Parkinson`s disease

There is considerable evidence showing that the neurodegenerative processes that lead to sporadic Parkinson`s disease (PD) begin many years before the appearance of the characteristic motor symptoms and that impairments in olfactory, cognitive and motor functions are associated with time-dependent disruption of dopaminergic neurotransmission in different brain areas. Midkine is a 13-kDa retinoic acid-induced heparin-binding growth factor involved in many biological processes in the central nervous system such as cell migration, neurogenesis and tissue repair. The abnormal midkine expression may be associated with neurochemical dysfunction in the dopaminergic system and cognitive impairments in rodents. Here, we employed adult midkine knockout mice (Mdk(-/-)) to further investigate the relevance of midkine in dopaminergic neurotransmission and in olfactory, cognitive and motor functions. Mdk(/-) mice displayed pronounced impairments in their olfactory discrimination ability and short-term social recognition memory with no gross motor alterations. Moreover, the genetic deletion of midkine decreased the expression of the enzyme tyrosine hydroxylase in the substantia nigra reducing partially the levels of dopamine and its metabolites in the olfactory bulb and striatum of mice. These findings indicate that the genetic deletion of midkine causes a partial loss of dopaminergic neurons and depletion of dopamine, resulting in olfactory and memory deficits with no major motor impairments. Therefore, Mdk(-/-) mice may represent a promising animal model for the study of the early stages of PD and for testing new therapeutic strategies to restore sensorial and cognitive processes in PD.

Increased circulating levels of matrix metalloproteinase (MMP)-8, MMP-9, and pro-inflammatory markers in patients with metabolic syndrome

Background: Metabolic syndrome (MetS) predisposes to cardiovascular complications. Increased concentrations of pro-inflammatory mediators and imbalanced concentrations of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) may reflect the pathophysiology of MetS. We compared the circulating levels of MMPs, TIMPs, and inflammatory mediators in MetS patients with those found in healthy controls. Methods: We studied 25 healthy subjects and 25 MetS patients. The plasma levels of pro-MMP-2 and pro-MMP-9 were determined by gelatin zymography. The plasma concentrations of MMP-8, MMP-3, TIMP-1, TIMP-2, monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), intercellular adhesion molecule (sICAM-1), and sP-selectin were measured by ELISA kits. Results: We found higher sP-selectin, sICAM-1, MCP-1, and IL-6 (all P<0.05) concentrations in MetS patients compared with healthy controls. No differences in pro-MMP-2, MMP-3, and TIMP-2 levels were found (all P>0.05). However, we found higher pro-MMP-9, MMP-8. and TIMP-1 levels in MetS patients compared with healthy controls (all P<0.05). Conclusions: Patients with MetS have increased circulating concentrations of pro-MMP-9, MMP-8, and TIMP-1 that are associated with increased concentrations of pro-inflammatory mediators and adhesion molecules. These findings suggest that MMPs may have a role in the increased cardiovascular risk of MetS patients. Pharmacological interventions targeting MMPs, especially MMP-9 and MMP-8 deserve further investigation in MetS patients. (C) 2009 Elsevier B.V. All rights reserved.

Bond strength of Epiphany (TM) Sealer combined with different adhesive systems photo-activated with LED and QTH

The Epiphany (TM) Sealer is a new dual-curing resin-based sealer and has been introduced as an alternative to gutta-percha and traditional root canal sealers. The canal filling is claimed to create a seal with the dentinal tubules within the root canal system producing a `monoblock` effect between the sealer and dentinal tubules. Therefore, considering the possibility to incorporate the others adhesive systems, it is important to study the bond strength of the resulting cement. Forty-eight root mandibular canines were sectioned 8-mm below CEJ. The dentine discs were prepared using a tapered diamond bur and irrigated with 1% NaOCl and 17% EDTA. Previous the application Epiphany (TM) Sealer, the Epiphany (TM) Primer, AdheSE, and One Up Bond F were applied to the root canal walls. The LED and QTH (Quartz Tungsten Halogen) were used to photo-activation during 45 s with power density of 400 and 720 mW/cm(2), respectively. The specimens were performed on a universal testing machine at a cross-head speed of 1 mm/min until bond failure occurred. The force was recorded and the debonding values were used to calculate Push-out bond strength. The analysis of variance (ANOVA) and Tukey`s post-hoc tests showed significant statistical differences (P < 0.05) to Epiphany (TM) Sealer/Epiphany (TM) Primer/QTH and EpiphanyTM Sealer/AdheSE/QTH, which had the highest mean values of bond strength. The efficiency of resin-based filling materials are dependent the type of light curing unit used including the power density, the polymerization characteristics of these resin-based filling materials, depending on the primer/adhesive used.

Bond Strength of Fiber Posts to Weakened Roots After Resin Restoration With Different Light-Curing Times

Introduction: This study evaluated the bond strength of translucent fiber posts to experimentally weakened radicular dentin restored with composite resin and polymerized with different light-exposure time. Methods: Roots of 60 maxillary incisors were used. Twenty-four hours after obturation, the filling materials of root canals were removed to a depth of 12 mm, and 4 groups were randomly formed. In 3 groups, root dentin was flared to produce a space between fiber post and canal walls. In the control group, the roots were not experimentally weakened. The flared roots were bulk restored with composite resin, which was light-activated through the translucent post for 40, 80, or 120 seconds. Posts were cemented, and after 24 hours, all roots were sectioned transversely in the coronal, middle, and apical regions, producing 1-mm-thick slices. Push-out test was performed, and failure modes were observed. Results The quantitative analysis showed significant statistical difference only among groups (P <.001). Comparing the weakened/restored groups, composite light-exposure time did not influence the results. Overall, adhesive failures occurred more frequently than other types of failures. Cohesive failures occurred only in the weakened/restored roots. Conclusions Intracanal root restoration with composite resin and translucent fiber posts provided similar or higher bond strength to dentin than the control group, regardless of the light-exposure time used for polymerization. (J Endod 2009;35:1034-1039)

IN VITRO FRACTURE RESISTANCE OF GLASS-FIBER AND CAST METAL POSTS WITH DIFFERENT LENGTHS

Statement of problem. Dental fractures can occur in endodontically treated teeth restored with posts. Purpose. The purpose of this study was to evaluate the in vitro fracture resistance of roots with glass-fiber and metal posts of different lengths. Material and methods. Sixty endodontically treated maxillary canines were embedded in acrylic resin, except for 4 mm of the cervical area, after removing the clinical crowns. The post spaces were opened with a cylindrical bur at low speed attached to a surveyor, resulting in preparations with lengths of 6 mm (group 6 mm), 8 mm (group 8 mm), or 10 mm (group 10 mm). Each group was divided into 2 subgroups according to the post material: cast post and core or glass-fiber post (n=30). The posts were luted with dual-polymerizing resin cement (Panavia F). Cast posts and cores of Co-Cr (Resilient Plus) crowns were made and cemented with zinc phosphate. Specimens were subjected to increasing compressive load (N) until fracture. Data were analyzed with 2-way ANOVA and the Tukey-Kramer test (alpha=.05). Results. The ANOVA analysis indicated significant differences (P<.05) among the groups, and the Tukey test revealed no significant difference among the metal posts of 6-mm length (26.5 N +/- 13.4), 8-mm length (25.2 N +/- 13.9), and 10-mm length (17.1 N +/- 5.2). Also, in the glass-fiber post group, there was no significant difference when posts of 8-mm length (13.4 N +/- 11.0) were compared with the 6-mm (6.9 N +/- 4.6) and 10-mm (31.7 N +/- 13.1) groups. The 10-mm-long post displayed superior fracture resistance, and the 6-mm-long post showed significantly lower mean values (P<.001). Conclusions. Within the limitations of this study, it was concluded that the glass-fiber post represents a viable alternative to the cast metal post, increasing the resistance to fracture of endodontically treated canines. (J Prosthet Dent 2009;101:183-188)

Morphological Alterations of Radicular Dentine Pretreated With Different Irrigating Solutions and Irradiated With 980-nm Diode Laser

Background: The topographical features of intraradicular dentine pretreated with sodium hypochlorite (NaOCl) or ethylenediamine tetraacetic acid (EDTA) followed by diode laser irradiation have not yet been determined. Purpose: To evaluate the alterations of dentine irradiated with 980-nm diode laser at different parameters after the surface treatment with NaOCl and EDTA. Study design: Roots of 60 canines were biomechanically prepared and irrigated with NaOCl or EDTA. Groups were divided according to the laser parameters: 1.5 W/CW; 1.5 W/100 Hz; 3.0 W/CW; 3.0 W/100 Hz and no irradiation (control). The roots were splited longitudinally and analyzed by scanning electron microscopy (SEM) in a quali-quatitative way. The scores were submitted to two-way Kruskal-Wallis and Dunn`s tests. Results: The statistical analysis demonstrated that the specimens treated only with NaOCl or EDTA (control groups) were statistically different (P < 0.05) from the laser-irradiated specimens, regardless of the parameter setting. The specimens treated with NaOCl showed a laser-modified surface with smear layer, fissures, and no visible tubules. Those treated with EDTA and irradiated by laser presented absence of smear layer, tubules partially exposed and melting areas. Conclusions: The tested parameters of 980-nm diode laser promoted similar alterations on dentine morphology, dependent to the type of surface pretreatment. Microsc. Res. Tech. 72:22-27, 2009. (C) 2008 Wiley-Liss, Inc.