Cardiac remodeling in a rat model of diet-induced obesity

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

Influence of photodynamic therapy on the development of ligature-induced periodontitis in rats

Background: the purpose of this study was to evaluate, histologically and radiographically, the effect of photodynamic therapy on the progression of experimentally induced periodontal disease in rats.Methods: Ligatures were placed at the first mandibular molar in rats. The animals were divided into four groups: group 1 (C) received no treatment; group 2 was treated topically with methylene blue (MB; 100 mu g/ml); group 3 was treated with low-level laser therapy (LLLT); and group 4 was treated topically with methylene blue followed by LLLT (4.5 J/cm(2)) (photodynamic therapy; PDT). Rats were sacrificed 5, 15, or 30 days postoperatively. Standardized radiographs were taken to measure bone loss around the mesial root surface of the first molar. Data were analyzed statistically (analysis of variance and Tukey test; P < 0.05). A scoring system was used to evaluate the connective tissue, periodontal ligament, and alveolar bone histologically. Data were analyzed statistically (Kruskal-Wallis test; P < 0.05).Results: Radiographic examination showed that there was significantly less bone loss in Group PDT compared to Group C at 5 and 15 days postoperatively. There was no significant difference in bone loss at 30 days. At 15 days, the histologic results showed significant differences in the extent of inflammatory reaction in the gingival tissue, with a greater extent of chronic inflammatory reaction in Group LLLT.Conclusion: PDT transiently reduced the periodontal tissue destruction.

The effect of N+ ion energy on the properties of ion bombarded plasma polymer films

This work describes the influence of the ion bombardment on the electrical, optical and mechanical properties of polymer films deposited from radio-frequency plasmas of benzene. Irradiations were conducted using N+ at 5 x 10(19) ions/m(2), varying the ion energy, E-0, from 0 to 150 keV. Film elemental composition was determined by Rutherford backscattering spectroscopy. Electrical resistivity and hardness were obtained by the two-point probe and nanoindentation technique, respectively. Ultraviolet-visible spectroscopy was employed to investigate the optical constants of the samples. Etching rate was determined by exposure of the films to reactive oxygen plasmas. Ion bombardment induced gradual loss of H and increase in C and O concentrations with Eo. As a consequence the electrical, optical and mechanical properties were drastically affected. Interpretation of these results is proposed in terms of chain cross-linking and unsaturation. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Energy Expenditure and Oxygen Consumption as Novel Biomarkers of Obesity-induced Cardiac Disease in Rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Lethal photosensitization in microbiological treatment of ligature-induced peri-implantitis: a preliminary study in dogs

This pilot study evaluated, by culture testing, the effectiveness of lethal photosensitization for the microbiological treatment of peri-implantitis in dogs. Experimental peri-implantitis was induced by ligature placement for 2 months. Following ligature removal, plaque control was instituted by scrubbing with 0.12% chlorhexidine daily for 12 months. Subsequently, mucoperiosteal flaps were elevated for scaling the implant surface. Microbial samples were obtained with paper points before and after treatment of implant surfaces by means of 100 microg/ml toluidine blue O (TBO,) and were exposed, for 80 s, to light with a wavelength of 685 nm from a 50 mW GaAlAs diode laser. The mean initial and final bacterial counts were 7.22 +/- 0.20 and 6.84 +/- 0.44 CFU/ml, respectively for TVC (P < 0.0001); 6.19 +/- 0.45 and 3.14 +/- 3.29 CFU/ml for P. intermedia/nigrescens (P = 0.001); 5.98 +/- 0.38 and 1.69 +/- 2.90 CFU/ml for Fusobacterium spp. (P = 0.001); and 6.07 +/- 0.22 to 1.69 +/- 2.94 CFU/ml for beta-hemolytic Streptococcus (P = 0.0039). It may be concluded that lethal photosensitization resulted in a reduction of the bacterial count. Complete elimination of bacteria was achieved in some samples.

Microbiologic and radiographic analysis of ligature-induced peri-implantitis with different dental implant surfaces

Purpose: The goal of this study was to evaluate microbiota and radiographic peri-implant bone loss associated with ligature-induced peri-implantitis. Materials and Methods: Thirty-six dental implants with 4 different surfaces (9 commercially pure titanium, 9 titanium plasma-sprayed, 9 hydroxyapatite, and 9 acid-etched) were placed in the edentulous mandibles of 6 dogs. After 3 months with optimal plaque control, abutment connection was performed. On days 0, 20, 40, and 60 after placement of cotton ligatures, both microbiologic samples and periapical radiographs were obtained. The presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Campylobacter spp, Capnocytophaga spp, Fusobacterium spp, beta-hemolytic Streptococcus, and Candida spp were evaluated culturally. Results: P intermedia/nigrescens was detected in 13.89% of implants at baseline and 100% of implants at other periods. P gingivalis was not detected at baseline, but after 20 and 40 days it was detected in 33.34% of implants and at 60 days it was detected in 29.03% of dental implants. Fusobacterium spp was detected in all periods. Streptococci were detected in 16.67% of implants at baseline and in 83.34%, 72.22%, and 77.42% of implants at 20, 40, and 60 days, respectively. Campylobacter spp and Candida spp were detected in low proportions. The total viable count analysis showed no significant differences among surfaces (P = .831), although a significant difference was observed after ligature placement (P < .0014). However, there was no significant qualitative difference, in spite of the difference among the periods. The peri-implant bone loss was not significantly different between all the dental implant surfaces (P = .908). Discussion and Conclusions: These data suggest that with ligature-induced peri-implantitis, both time and periodontal pathogens affect all surfaces equally after 60 days.

Toward an Explanation of the Genesis of Ketamine-Induced Perceptual Distortions and Hallucinatory States

The NMDA receptor (NMDAR) channel has been proposed to function as a coincidence-detection mechanism for afferent and reentrant signals, supporting conscious perception, learning, and memory formation. In this paper we discuss the genesis of distorted perceptual states induced by subanesthetic doses of ketamine, a well-known NMDA antagonist. NMDAR blockage has been suggested to perturb perceptual processing in sensory cortex, and also to decrease GABAergic inhibition in limbic areas (leading to an increase in dopamine excitability). We propose that perceptual distortions and hallucinations induced by ketamine blocking of NMDARs are generated by alternative signaling pathways, which include increase of excitability in frontal areas, and glutamate binding to AMPA in sensory cortex prompting Ca++ entry through voltage-dependent calcium channels (VDCCs). This mechanism supports the thesis that glutamate binding to AMPA and NMDARs at sensory cortex mediates most normal perception, while binding to AMPA and activating VDCCs mediates some types of altered perceptual states. We suggest that Ca++ metabolic activity in neurons at associative and sensory cortices is an important factor in the generation of both kinds of perceptual consciousness.

Adjunctive antimicrobial photodynamic treatment of experimentally induced periodontitis in rats with ovariectomy

Background: The aim of this study is to compare antimicrobial photodynamic therapy (aPDT) as an adjunctive therapy to scaling and root planing (SRP) for the treatment of experimentally induced periodontitis in rats with ovariectomy (OVX) that are or are not treated with estrogen replacement. Methods: A total of 270 female rats were divided into three groups: 1) normal rats; 2) rats with OVX; and 3) rats with OVX with estrogen replacement. Periodontal disease was induced through the introduction of a cotton thread around the mandibular left first molar. After 7 days, the ligature was removed, and the rats were randomly divided into the following treatment groups: 1) SRP plus saline solution; 2) SRP plus low-level laser therapy (LLLT); and 3) SRP plus toluidine blue O irrigation followed by LLLT. Ten rats from each group were euthanized at days 7, 15, and 30 after dental treatment. Bone loss (BL) in the furcation region was evaluated using histometric and immunohistochemical analyses. Results: aPDT treatment resulted in reduced BL compared with SRP treatment at all time points. Additionally, rats treated with aPDT exhibited reduced numbers of tartrate-resistant acid-phosphatase-positive cells and more proliferating cell nuclear antigen-positive cells in all treatment groups regardless of estrogen status. Whereas rats treated with aPDT showed weak immunoreactivity to the receptor activator of nuclear factor-k B ligand at day 7 post-treatment, strong osteoprotegerin immunoreactivity was observed at day 15 post-treatment. Conclusion: aPDT is an effective adjunctive therapy for the treatment of periodontitis in rats with OVX that are or are not given estrogen replacement therapy.

Effects of laser beam energy on the pulsed Nd:YAG laser welding of thin sheet corrosion resistant materials

The aim of this study was to value the possibility to join, for pulsed Nd:YAG laser welding, thin foils lap joints for sealing components in corrosive environment. Experimental investigations were carried out using a pulsed neodymium: yttrium aluminum garnet laser weld to examine the influence of the pulse energy in the characteristics of the weld fillet. The pulse energy was varied from 1.0 to 2.5 J at increments of 0.25 J with a 4 ms pulse duration. The base materials used for this study were AISI 316L stainless steel and Ni-based alloys foils with 100 mu m thickness. The welds were analyzed by electronic and optical microscopy, tensile shear tests and micro hardness. The results indicate that pulse energy control is of considerable importance to thin foil weld quality because it can generate good mechanical properties and reduce discontinuities in weld joints. The ultimate tensile strength of the welded joints increased at first and then decreased as the pulse energy increased. In all the specimens, fracture occurred in the top foil heat-affected zone next to the fusion line. The microhardness was almost uniform across the parent metal, HAZ and weld metal. A slight increase in the fusion zone and heat-affected zone compared to those measured in the base metal was observed. This is related to the microstructural refinement in the fusion zone, induced by rapid cooling of the laser welding. The process appeared to be very sensitive to the gap between couples.

Physical and chemical matrix effects in soil carbon quantification using laser-induced breakdown spectroscopy

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

Prenatal zinc prevents communication impairments and BDNF disturbance in a rat model of autism induced by prenatal lipopolysaccharide exposure

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