Effects of Dextrose and Lipopolysaccharide on the Corrosion Behavior of a Ti-6Al-4V Alloy with a Smooth Surface or Treated with Double-Acid-Etching

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In situ protocol for the detemination of dose-response effect of low-fluoride dentifrices on enamel remineralization

No in situ protocol has assessed the dose-response effects of fluoride dentifrices involving low-fluoride formulations. Objective: To assess the ability of an in situ remineralization model in determining dose-response effects of dentifrices containing low fluoride concentrations ([F]) on bovine enamel. Material and Methods: Volunteers wore palatal appliances containing demineralized enamel blocks and brushed their teeth and devices with the dentifrices supplied (double-blind, crossover protocol) separately for 3 and 7 days. Surface hardness (SH), integrated subsurface hardness (AKHN) and [F] in enamel were determined. Data were analyzed by ANOVA, Tukey's test and Pearson's correlation (p<0.05). Results: Dose-response relationships were verified between [F] in dentifrices and SH, AKHN and enamel [F]. Higher correlation coefficients between enamel [F] and SH and AKHN were obtained for the 3-day period. Significant differences in SH and AKHN were observed among all groups for the 3-day period, but not between 0-275, 275-550, and 550-1,100 mu g F/g dentifrices for the 7-day period, nor between 3- and 7-day periods for the 1,100 mu g F/g groups. Conclusions: Considering that the peak remineralization capacity of the conventional dentifrice (1,100 mu g F/g) was achieved in 3 days, this experimental period could be used in future studies assessing new dentifrice formulations, especially at low-fluoride concentrations.

Soil phosphorus availability and soybean response to phosphorus starter fertilizer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

On the contact stiffness and nonlinear vibration of an elastic body with a rough surface in contact with a rigid flat surface

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The physicochemical characterization and in vivo response of micro/nanoporous bioactive ceramic particulate bone graft materials

In this study, the physicochemical characteristics of calcium phosphate based bioactive ceramics of different compositions and blends presenting similar micro/nanoporosity and micrometer scale surface texture were characterized and evaluated in an in vivo model. Prior to the animal experiment, the porosity, surface area, particle size distribution, phase quantification, and dissolution of the materials tested were evaluated. The bone regenerative properties of the materials were evaluated using a rabbit calvaria model. After 2, 4, and 8 weeks, the animals were sacrificed and all samples were subjected to histologic observation and histomorphometric analysis. The material characterization showed that all materials tested presented variation in particle size, porosity and composition with different degrees of HA/TCP/lower stoichiometry phase ratios. Histologically, the calvarial defects presented temporal bone filling suggesting that all material groups were biocompatible and osteoconductive. Among the different materials tested, there were significant differences found in the amount of bone formation as a function of time. At 8 weeks, the micro/nanoporous material presenting similar to 55,TCP:45%,HA composition ratio presented higher amounts of new bone regeneration relative to other blends and a decrease in the amount of soft tissue infiltration. (C) 2014 Elsevier B.V. All rights reserved.

Melatonin attenuates the TLR4-mediated inflammatory response through MyD88-and TRIF-dependent signaling pathways in an in vivo model of ovarian cancer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of summertime mesoscale convective systems on the heat balance and surface mixed layer dynamics of a large Amazonian hydroelectric reservoir

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Characterization of grazing bifurcation in airfoils with control surface freeplay nonlinearity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Periapical Tissue Response After Use of Intermediate Restorative Material, Gutta-Percha, Reinforced Zinc Oxide Cement, and Mineral Trioxide Aggregate as Retrograde Root-End Filling Materials: A Histologic Study in Dogs

Purpose: To investigate the periapical tissue response of 4 different retrograde root-filling materials, ie, intermediate restorative material, thermoplasticized gutta-percha, reinforced zinc oxide cement (Super-EBA), and mineral trioxide aggregate (MTA), in conjunction with an ultrasonic root-end preparation technique in an animal model. Materials and Methods: Vital roots of the third and fourth right mandibular premolars in 6 healthy mongrel dogs were apicectomized and sealed with 1 of the materials using a standardized surgical procedure. After 120 days, the animals were sacrificed and the specimens were analyzed radiologically, histologically, and scanning electron microscopically. The Fisher exact test was performed on the 2 outcome values. Results: Twenty-three sections were analyzed histologically. Evaluation showed better re-establishment of the periapical tissues and generally lower inflammatory infiltration in the sections from teeth treated with the intermediate restorative material and the MTA. New root cement on the resected dentin surfaces was seen on all sections regardless of the used material. New hard tissue formation, directly on the surface of the material, was seen only in the MTA sections. There was no statistical difference in outcome among the tested materials. Conclusions: The results from this dog model favor the intermediate restorative material and MTA as retrograde fillings when evaluating the bone defect regeneration. MTA has the most favorable periapical tissue response when comparing the biocompatibility of the materials tested. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70:2041-2047, 2012

Distinct mechanisms underlie adaptation of proximal tubule Na+/H+ exchanger isoform 3 in response to chronic metabolic and respiratory acidosis

The Na+/H+ exchanger isoform 3 (NHE3) is essential for HCO3- reabsorption in renal proximal tubules. The expression and function of NHE3 must adapt to acid-base conditions. The goal of this study was to elucidate the mechanisms responsible for higher proton secretion in proximal tubules during acidosis and to evaluate whether there are differences between metabolic and respiratory acidosis with regard to NHE3 modulation and, if so, to identify the relevant parameters that may trigger these distinct adaptive responses. We achieved metabolic acidosis by lowering HCO3- concentration in the cell culture medium and respiratory acidosis by increasing CO2 tension in the incubator chamber. We found that cell-surface NHE3 expression was increased in response to both forms of acidosis. Mild (pH 7.21 +/- 0.02) and severe (6.95 +/- 0.07) metabolic acidosis increased mRNA levels, at least in part due to up-regulation of transcription, whilst mild (7.11 +/- 0.03) and severe (6.86 +/- 0.01) respiratory acidosis did not up-regulate NHE3 expression. Analyses of the Nhe3 promoter region suggested that the regulatory elements sensitive to metabolic acidosis are located between -466 and -153 bp, where two consensus binding sites for SP1, a transcription factor up-regulated in metabolic acidosis, were localised. We conclude that metabolic acidosis induces Nhe3 promoter activation, which results in higher mRNA and total protein level. At the plasma membrane surface, NHE3 expression was increased in metabolic and respiratory acidosis alike, suggesting that low pH is responsible for NHE3 displacement to the cell surface.

KCNQ Channels Determine Serotonergic Modulation of Ventral Surface Chemoreceptors and Respiratory Drive

Chemosensitive neurons in the retrotrapezoid nucleus (RTN) regulate breathing in response to CO2/H+ changes. Their activity is also sensitive to neuromodulatory inputs from multiple respiratory centers, and thus they serve as a key nexus of respiratory control. However, molecular mechanisms that control their activity and susceptibility to neuromodulation are unknown. Here, we show in vitro and in vivo that KCNQ channels are critical determinants of RTN neural activity. In particular, we find that pharmacological block of KCNQ channels (XE991, 10 mu M) increased basal activity and CO2 responsiveness of RTN neurons in rat brain slices, whereas KCNQ channel activation (retigabine, 2-40 mu M) silenced these neurons. Interestingly, we also find that KCNQ and apamin-sensitive SK channels act synergistically to regulate firing rate of RTN chemoreceptors; simultaneous blockade of both channels led to a increase in CO2 responsiveness. Furthermore, we also show that KCNQ channels but not SK channels are downstream effectors of serotonin modulation of RTN activity in vitro. In contrast, inhibition of KCNQ channel did not prevent modulation of RTN activity by Substance P or thyrotropin-releasing hormone, previously identified neuromodulators of RTN chemoreception. Importantly, we also show that KCNQ channels are critical for RTN activity in vivo. Inhibition of KCNQ channels lowered the CO2 threshold for phrenic nerve discharge in anesthetized rats and decreased the ventilatory response to serotonin in awake and anesthetized animals. Given that serotonergic dysfunction may contribute to respiratory failure, our findings suggest KCNQ channels as a new therapeutic avenue for respiratory complications associated with multiple neurological disorders.

Histomorphometric analysis of inflammatory response and necrosis in re-implanted central incisor of rats treated with low-level laser therapy

Low-level laser therapy is a tool employed in the management of post-operative inflammation process and in the enhancement of reparative process. The aim of the study was to perform histological evaluation of dental and periodontal ligament of rats central upper-left incisor teeth re-implanted and irradiated with low-level laser (InGaAl, 685 nm, 50 J/cm(2)) 15, 30, and 60 days after re-implantation. Seventy-two male rats had the central upper left incisor removed and kept for 15 min on dry gauze before replantation. Laser was irradiated over the root surface and empty alveolus prior replantation and over surrounding mucosa after the re-implantation. After histological procedures, all slices were analyzed regarding external resorption area and histological aspects. We observed an increase of root resorption (p < 0.05) in the control group compared to the laser group at 15, 30, and 60 days. These results showed that the laser groups developed less root resorption areas than the control group in all experimental periods. Additionally, histological analysis revealed less inflammatory cells and necrotic areas in laser groups.

Radiation balance at the surface in the city of So Paulo, Brazil: diurnal and seasonal variations

The main goal of this work is to describe the diurnal and seasonal variations of the radiation balance components at the surface in the city of So Paulo based on observations carried out during 2004. Monthly average hourly values indicate that the amplitudes of the diurnal cycles of net radiation (Q*), downwelling and upwelling shortwave radiation (SW(DW), SW(UP)), and longwave radiations (LW(DW), LW(UP)) in February were, respectively, 37%, 14%, 19%, 11%, and 5% larger than they were in August. The monthly average daily values indicate a variation of 60% for Q*, with a minimum in June and a maximum in December; 45% for SW(DW), with a minimum in May and a maximum in September; 50% for SW(UP), with a minimum in June and a maximum in September; 13% for LW(DW), with a minimum in July and a maximum in January; and 9% for LW(UP), with a minimum in July and a maximum in February. It was verified that the atmospheric broadband transmissivity varied from 0.36 to 0.57; the effective albedo of the surface varied from 0.08 to 0.10; and the atmospheric effective emissivity varied from 0.79 to 0.92. The surface effective emissivity remained approximately constant and equal to 0.96. The albedo and surface effective emissivity for So Paulo agreed with those reported for urban areas in Europe and North America cities. This indicates that material and geometric effects on albedo and surface emissivity in So Paulo are similar to ones observed in typical middle latitudes cities. On the other hand, it was found that So Paulo city induces an urban heat island with daytime maximum intensity varying from 2.6A degrees C in July (16:00 LT) to 5.5A degrees C in September (15:00 LT). The analysis of the radiometric properties carried out here indicate that this daytime maximum is a primary response to the seasonal variation of daily values of net solar radiation at the surface.

GM-CSF Priming Drives Bone Marrow-Derived Macrophages to a Pro-Inflammatory Pattern and Downmodulates PGE(2) in Response to TLR2 Ligands

In response to pathogen recognition by Toll-like receptors (TLRs) on their cell surface, macrophages release lipid mediators and cytokines that are widely distributed throughout the body and play essential roles in host responses. Granulocyte macrophage colony-stimulating factor (GM-CSF) is important for the immune response during infections to improve the clearance of microorganisms. In this study, we examined the release of mediators in response to TLR2 ligands by bone marrow-derived macrophages (BMDMs) primed with GM-CSF. We demonstrated that when stimulated with TLR2 ligands, non-primed BMDMs preferentially produced PGE(2) in greater amounts than LTB4. However, GM-CSF priming shifted the release of lipid mediators by BMDMs, resulting in a significant decrease of PGE(2) production in response to the same stimuli. The decrease of PGE(2) production from primed BMDMs was accompanied by a decrease in PGE-synthase mRNA expression and an increase in TNF-alpha and nitric oxide (NO) production. Moreover, some GM-CSF effects were potentiated by the addition of IFN-gamma. Using a variety of TLR2 ligands, we established that PGE(2) release by GM-CSF-primed BMDMs was dependent on TLR2 co-receptors (TLR1, TLR6), CD14, MyD88 and the nuclear translocation of NF kappa B but was not dependent on peroxisome proliferator-activated receptor-gamma (PPAR-gamma) activation. Indeed, GM-CSF priming enhanced TLR2, TLR4 and MyD88 mRNA expression and phospho-I kappa B alpha formation. These findings demonstrate that GM-CSF drives BMDMs to present a profile relevant to the host during infections.

Regulation of ventral surface CO2/H+-sensitive neurons by purinergic signalling

Central chemoreception is the mechanism by which the brain regulates breathing in response to changes in tissue CO2/H+. Abrainstemregion called the retrotrapezoid nucleus (RTN) contains a population of CO2/H+-sensitive neurons that appears to function as an important chemoreceptor. Evidence also indicates that CO2-evoked ATP release from RTN astrocytes modulates activity of CO2/H+-sensitive neurons; however, the extent to which purinergic signalling contributes to chemoreception by RTN neurons is not clear and the mechanism(s) underlying CO2/H+-evoked ATP release is not fully elucidated. The goals of this study are to determine the extent to which ATP contributes to RTN chemoreception both in vivo and in vitro, andwhether purinergic drive to chemoreceptors relies on extracellularCa(2+) or gap junction hemichannels. We also examine the possible contribution of P2Y1 receptors expressed in theRTNto the purinergic drive to breathe. We showthat purinergic signalling contributes, in part, to the CO2/H+ sensitivity of RTN neurons. In vivo, phrenic nerve recordings of respiratory activity in adult rats show that bilateral injections of pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (PPADS, a P2 receptor blocker) decreased the ventilatory response to CO2 by 30%. In vitro, loose-patch recordings from RTN neurons show that P2 receptor blockers decreased responsiveness to both 10% and 15% CO2 also by 30%. In the slice, the contribution of purinergic signalling to RTN chemoreception did not increase with temperature (22-35 degrees C) and was retained in low extracellular Ca2+ medium. Conversely, the gap junction blockers carbenoxolone and cobalt decreased neuronal CO2/H+ sensitivity by an amount similar to P2 receptor antagonists. Inhibition of the P2Y1 receptor in the RTN had no effect on CO2 responsivness in vitro or in vivo; thus, the identity of P2 receptors underlying the purinergic component of RTN chemoreception remains unknown. These results support the possibility that CO2/H+-evoked ATP release is mediated by a mechanism involving gap junction hemichannels.