Evaluation of superficial microhardness in dental enamel with different eruptive ages

This study evaluated the superficial microhardness of enamel in teeth at different posteruptive ages (before eruption in the oral cavity, 2-3 years after eruption, 4-10 years after eruption and more than 10 years after eruption). The study sample was composed of 134 specimens of human enamel. One fragment of each tooth was obtained from the flattest central portion of the crown to produce specimens with 3 x 3 mm. The enamel blocks were minimally flattened out and polished in order to obtain a flat surface parallel to the base, which is fundamental for microhardness testing. Microhardness was measured with a microhardness tester and a Knoop diamond indenter, under a static load of 25 g applied for 5 seconds. Comparison between the superficial microhardness obtained for the different groups was performed by analysis of Student's t test. The results demonstrated that superficial microhardness values have a tendency to increase over the years, with statistically significant difference only between unerupted enamel and that with more than 10 years after eruption. According to the present conditions and methodology, it was concluded that there were differences between the superficial micro-hardness of specimens at different eruptive ages, revealing an increasing mineralization. However, this difference was significant only between unerupted specimens and those with more than 10 years after eruption.

Cardiopulmonary effects and eyeball centralization with low-dose atracurium in spontaneously breathing, anesthetized dogs

The objective was to determine the cardiopulmonary effects and eyeball centralization time obtained with 15 or 30µg kg-1 of atracurium in anesthetized dogs under spontaneous breathing. Eighteen healthy adult mixed-breed dogs were used, which received 0.1mg kg-1 acepromazine and 0.5mg kg-1 morphine IM, followed by 4mg kg-1 propofol IV and maintained on isoflurane anesthesia with spontaneous breathing. Animals received 1mL 0.9% NaCl IV (CG), 15µg kg-1 (G15) or 30µg kg-1 (G30) of atracurium IV. Eyeball centralization time was measured; heart rate (HR), systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures, respiratory rate (RR), tidal volume (Vt) and minute volume (Vm) were determined every 5min, and pH, arterial CO2 pressure (PaCO2 ), arterial O2 pressure (PaO2 ), hemoglobin oxygen saturation (SaO2 ), bicarbonate (HCO3-) and base excess (BE) every 15min until 60min. Both doses of atracurium produced a similar period of eyeball centralization. Vt in groups treated with atracurium was lower than in CG up to 15min. Vm in G15 differed from CG up to 10min and in G30 up to 25min. No differences were observed for cardiovascular parameters, RR, SaO2, PaO2, HCO3- and BE. pH decreased in CG between 30 and 60min and in G15 and G30 at 15min. G30 differed from CG between 15 and 30min. PaCO2 in GC differed from baseline between 30 and 60min and in G15 differed at 15min. Atracurium at the dose of 15µg kg-1 is adequate for short corneal procedures in inhalant-anesthetized dogs under spontaneous breathing.

Effect of therapeutic dose X rays on mechanical and chemical properties of esthetic dental materials

The aim of this study was to investigate the influence of therapeutic dose X rays on the microhardness (MH) and degree of conversion (DC) of two different esthetic restorative dental materials. The materials were photo-activated with a LED light-curing unit using three cure-times: 5, 20 and 40 seconds. The photo-activation was carried out in two distinct periods: before and after irradiation with doses of 5, 35 and 70 Gy, from a 6 MV X rays beam. In accordance with the methodology used, it was conclude that a therapeutic dose does not have a detrimental effect on the photoinitiator molecules, because the photo-activation occurred after they were irradiated. When the irradiation was applied before photo-activation, the materials showed MH improvement, but when photo-activation was performed after irradiation, there was less improvement. However, there was no correlation between MH and DC. Thus, a therapeutic dose applied to cured material can promote linking and breaking of chain bonds in a non-linear way.

Dose de exposição radiométrica de granitos do estado de Rondônia, Brasil

Este trabalho avaliou a concentração dos radioelementos K, eU e eTh em amostras de granitos do Estado de Rondônia, Brasil. A análise estatística dos dados obtidos indicou que eles seguem distribuições lognormais. Os valores modais encontrados correspondem a cerca de 11% para K, 29 ppm para eU e 85 ppm para eTh. Correlações diretas significativas foram determinadas entre as concentrações dos três radioelementos, isto é, r = 0,71 (entre K e eU), r = 0,72 (entre K e eTh)e r = 0,72 (entre eU e eTh), sugerindo que são congruentes os processos de seu acúmulo nos minerais das rochas analisadas. Os dados de concentração permitiram estimar a taxa de dose absorvida de radiação no ar acima de 1 m do nível do terreno, a qual também segue uma distribuição lognormal, com valor modal de 2,7 mSv/ano, que é ligeiramente superior à média global de 2,4 mSv/ano. Os resultados obtidos também permitiram avaliar, do ponto de vista radiométrico, se os granitos analisados são adequados para emprego como revestimento em construção civil.

High-energy events and short-term changes in superficial beach sediments

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dose-response effects of systemic anandamide administration in mice sequentially submitted to the open field and elevated plus-maze tests

The endocannabinoid system is involved in the control of many physiological functions, including the control of emotional states. In rodents, previous exposure to an open field increases the anxiety-like behavior in the elevated plus-maze. Anxiolytic-like effects of pharmacological compounds that increase endocannabinoid levels have been well documented. However, these effects are more evident in animals with high anxiety levels. Several studies have described characteristic inverted U-shaped dose-response effects of drugs that modulate the endocannabinoid levels. However, there are no studies showing the effects of different doses of exogenous anandamide, an endocannabinoid, in animal models of anxiety. Thus, in the present study, we determined the dose-response effects of exogenous anandamide at doses of 0.01, 0.1, and 1.0 mg/kg in C57BL/6 mice (N = 10/group) sequentially submitted to the open field and elevated plus-maze. Anandamide was diluted in 0.9% saline, ethyl alcohol, Emulphor® (18:1:1) and administered ip (0.1 mL/10 g body weight); control animals received the same volume of anandamide vehicle. Anandamide at the dose of 0.1 mg/kg (but not of 0.01 or 1 mg/kg) increased (P < 0.05) the time spent and the distance covered in the central zone of the open field, as well as the exploration of the open arms of the elevated plus-maze. Thus, exogenous anandamide, like pharmacological compounds that increase endocannabinoid levels, promoted a characteristic inverted U-shaped dose-response effect in animal models of anxiety. Furthermore, anandamide (0.1 mg/kg) induced an anxiolytic-like effect in the elevated plus-maze (P < 0.05) after exposing the animals to the open field test.

Effects of high-dose creatine supplementation on kidney and liver responses in sedentary and exercised rats

This study evaluated the effects of high-dose of short-term creatine supplementation (5g.kg(-1). day(-1) to 1 week) and long-term creatine supplementation (1g.kg(-1). day(-1) to 4-8 weeks) on kidney and liver structure and function of sedentary and exercised Wistar rats ( Exercise sessions consisted of swimming at 80% of maximal work load supported during 5 days per week with daily sessions of 60 minutes throughout the duration of the supplementation). Seventy-two animals ( 245 +/- 5g) were divided into four groups (n = 18): control diet Sedentary ( SED), Creatine diet Sedentary (CRE), control diet Exercised (EXE), and Creatine diet Exercised (EXECRE). Histological and blood biochemical studies were performed after one, four, and eight weeks of creatine supplementation and exercise ( n = 6). No differences were found when comparing SED, EXE and EXECRE groups for kidney and liver structure and function at one, four and eight weeks. However, the CRE group showed higher levels of creatinine (1.1 +/- 0.2 vs. 0.4 +/- 0.1 mg.dl(-1); p < 0.05), and urea ( 37 +/- 3 vs. 19 +/- 1 mg. dl(-1); p < 0.05) when compared with all others groups at four and eight weeks. At eight weeks, the CRE group presented increased levels of ALT (41 +/- 7 vs. 23 +/- 7 U.L(-1); p < 0.05), AST (89 +/- 6 vs. 62 +/- 5 U. L(-1); p < 0.05), GGT (8.0 +/- 0.9 vs. 3.9 +/- 1.0 U. L(-1); p < 0.05), and AP (125 +/- 10 vs. 69 +/- 9 U. L(-1); p < 0.05) also when compared with all others groups. Moreover, the CRE group demonstrated some structural alterations indicating renal and hepatic damage at four and eight weeks, respectively. These results suggest that long-term creatine supplementation (up to 4-8 weeks) may adversely affect kidney and liver structure and function of sedentary but not of exercised rats.

High-Dose Antipsychotic Medication; A Practical Pocket Checklist

There is evidence that a significant number of patients with schizophrenia and other chronic psychotic psychosis are prescribed high-dose antipsychotic drugs despite the fact that clinical guidelines recommend the routine use of a single antipsychotic drug in a standard dose. The prescriptions for high-dose and combined antipsychotic drugs are relatively common in clinical practice. This occurs despite the fact that results of published trials of high-dose antipsychotic drug treatment for schizophrenia provide little evidence to support effectiveness of using high-dose antipsychotic treatment and most importantly such strategy is not recommended. Moreover, there is mounting evidence of higher incidence of side effects and mortality associated with high dose antipsychotic treatment. Therefore we are presenting a practical pocket checklist which is aimed at minimizing predicted and unpredicted side effects during such treatments.

Ablation Rate and Morphology of Superficial and Deep Dentin Irradiated with Different Er:YAG Laser Energy Levels

Objective: In this study we evaluated the ablation rate of superficial and deep dentin irradiated with different Er:YAG laser energy levels, and observed the micromorphological aspects of the lased substrates with a scanning electron microscope (SEM). Background Data: Little is known about the effect of Er: YAG laser irradiation on different dentin depths. Materials and Methods: Sixty molar crowns were bisected, providing 120 specimens, which were randomly assigned into two groups ( superficial or deep dentin), and later into five subgroups (160, 200, 260, 300, or 360 mJ). Initial masses of the specimens were obtained. After laser irradiation, the final masses were obtained and mass losses were calculated followed by the preparation of specimens for SEM examination. Mass-loss values were subjected to two-way ANOVA and Fisher's least significant difference multiple-comparison tests (p < 0.05). Results: There was no difference between superficial and deep dentin. A significant and gradual increase in the mass-loss values was reached when energies were raised, regardless of the dentin depth. The energy level of 360 mJ showed the highest values and was statistically significantly different from the other energy levels. The SEM images showed that deep dentin was more selectively ablated, especially intertubular dentin, promoting tubule protrusion. At 360 mJ the micromorphological features were similar for both dentin depths. Conclusion: The ablation rate did not depend on the depth of the dentin, and an energy level lower than 360 mJ is recommended to ablate both superficial and deep dentin effectively without causing tissue damage.

Low-Level Laser Irradiation (InGaAlP-660 nm) Increases Fibroblast Cell Proliferation and Reduces Cell Death in a Dose-Dependent Manner

Background and Objective: Impaired cell metabolism and increased cell death in fibroblast cells are physiological features of chronic tendinopathy. Although several studies have shown that low-level laser therapy (LLLT) at certain parameters has a biostimulatory effect on fibroblast cells, it remains uncertain if LLLT effects depend on the physiological state. Study Design/Material and Methods: High-metabolic immortal cell culture and primary human keloid fibroblast cell culture were used in this study. Trypan blue exclusion and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test were used to determine cell viability and proliferation. Propidium iodide stain was used for cell-cycle analysis by flow cytometry. Laser irradiation was performed daily on three consecutive days with a GaAlAs 660-nm laser (mean output: 50 mW, spot size 2 mm(2), power density = 2.5 W/cm(2)) and a typical LLLT dose and a high LLLT dose (irradiation times: 60 or 420 s; fluences: 150 or 1050 J/cm(2); energy delivered: 3 or 21 J). Results: Primary fibroblast cell culture from human keloids irradiated with 3 J showed significant proliferation by the trypan blue exclusion test (p < 0.05), whereas the 3T3 cell culture showed no difference using this method. Propidium iodide staining flow cytometry data showed a significant decrease in the percentage of cells being in proliferative phases of the cell cycle (S/g(2)/M) when irradiated with 21 J in both cell types (hypodiploid cells increased). Conclusions: Our data support the hypothesis that the physiological state of the cells affects the LLLT results, and that high-metabolic rate and short-cell-cycle 3T3 cells are not responsive to LLLT. In conclusion, LLLT with a dose of 3 J reduced cell death significantly, but did not stimulate cell cycle. A LLLT dose of 21 J had negative effects on the cells, as it increased cell death and inhibited cell proliferation.

Respiratory allergy to Blomia tropicalis: Immune response in four syngeneic mouse strains and assessment of a low allergen-dose, short-term experimental model

Background: The dust mite Blomia tropicalis is an important source of aeroallergens in tropical areas. Although a mouse model for B. tropicalis extract (BtE)-induced asthma has been described, no study comparing different mouse strains in this asthma model has been reported. The relevance and reproducibility of experimental animal models of allergy depends on the genetic background of the animal, the molecular composition of the allergen and the experimental protocol. Objectives: This work had two objectives. The first was to study the anti-B. tropicalis allergic responses in different mouse strains using a short-term model of respiratory allergy to BtE. This study included the comparison of the allergic responses elicited by BtE with those elicited by ovalbumin in mice of the strain that responded better to BtE sensitization. The second objective was to investigate whether the best responder mouse strain could be used in an experimental model of allergy employing relatively low BtE doses. Methods: Groups of mice of four different syngeneic strains were sensitized subcutaneously with 100 mu g of BtE on days 0 and 7 and challenged four times intranasally, at days 8, 10, 12, and 14, with 10 mu g of BtE. A/J mice, that were the best responders to BtE sensitization, were used to compare the B. tropicalis-specific asthma experimental model with the conventional experimental model of ovalbumin (OVA)-specific asthma. A/J mice were also sensitized with a lower dose of BtE. Results: Mice of all strains had lung inflammatory-cell infiltration and increased levels of anti-BtE IgE antibodies, but these responses were significantly more intense in A/J mice than in CBA/J, BALB/c or C57BL/6J mice. Immunization of A/J mice with BtE induced a more intense airway eosinophil influx, higher levels of total IgE, similar airway hyperreactivity to methacholine but less intense mucous production, and lower levels of specific IgE, IgG1 and IgG2 antibodies than sensitization with OVA. Finally, immunization with a relatively low BtE dose (10 mu g per subcutaneous injection per mouse) was able to sensitize A/J mice, which were the best responders to high-dose BtE immunization, for the development of allergy-associated immune and lung inflammatory responses. Conclusions: The described short-term model of BtE-induced allergic lung disease is reproducible in different syngeneic mouse strains, and mice of the A/J strain was the most responsive to it. In addition, it was shown that OVA and BtE induce quantitatively different immune responses in A/J mice and that the experimental model can be set up with low amounts of BtE.

Induction of mitotic crossing-over in diploid strains of Aspergillus nidulans using low-dose X-rays

As a contribution towards detecting the genetic effects of low doses of genotoxic physical agents, this paper deals with the consequences of low-dose X-rays in the Aspergillus nidulans genome. The irradiation doses studied were those commonly used in dental clinics (1-5 cGy). Even very low doses promoted increased mitotic crossing-over frequencies in diploid strains heterozygous for several genetic markers including the ones involved in DNA repair and recombination mechanisms. Genetic markers of several heterozygous strains were individu`ally analyzed disclosing that some markers were especially sensitive to the treatments. These markers should be chosen as bio-indicators in the homozygotization index assay to better detect the recombinogenic/carcinogenic genomic effects of low-dose X-rays.

Toxicity of High-Dose Intravitreal Adalimumab (Humira) in the Rabbit

Purpose: To evaluate the ocular toxicity of escalating doses of intravitreous adalimumab (Humira (R)) in the rabbit eye. Methods: Thirty New Zealand albino rabbits received intravitreous injections of 0.5mg (6 eyes), 1.0mg (6 eyes), 2.5mg (6 eyes), 5mg (6 eyes), and 10mg (6 eyes) adalimumab. Slit lamp biomicroscopy and fundoscopy were carried out at baseline, day 7, and day 14 after intravitreous injection, whereas electroretinography (ERG) was carried out at baseline and day 14. Animals were euthanized on day 14, and histopathological examination of the eyes was performed. Results: Slit lamp biomicroscopy and fundoscopy were normal in all eyes receiving doses up to 5mg. In the 10mg group, 3 of 6 eyes showed mild anterior chamber inflammatory reaction on day 7. Similarly, scotopic and photopic a- and b-wave ERG amplitudes at baseline and day 14 were similar in all groups up to 5mg, but there was a significant decrease in the photopic-wave ERG response in the 10mg group (P = 0.046). Finally, histopathology demonstrated no differences among eyes receiving balanced salt solution, 0.5, 1.0, 2.5, 5.0, or 10mg of adalimumab. Conclusions: Intravitreous adalimumab exhibited no associated ocular short-term toxicity in rabbit eyes up to the 5mg dose. In the 10mg group mild clinical findings and ERG amplitude reduction could reflect early toxicity.

The synergism between high superficial roughness and corrosive atmosphere in the fatigue behavior of the SAE 1045 steel

The fatigue behavior of the SAE 1045 steel in four different conditions is reported in this paper. Four treatments were tested: polished surface, corrosive atmosphere (sugar cane juice), low quality roughness (typical equivalent surface of the shaft cane mill) and the combined condition of the two last treatments involved. Fatigue tests were performed in rotating bending conditions and the values of fatigue strength for the different situations from tests were obtained. The diminution in fatigue strength for the synergy condition of rough surface and corrosive atmosphere was of 8.7%, result statistically representative with less than 0.01% of uncertainty.

Nitrogen, phosphorus and potassium dose effect in the graft box of lemon tree (of the family Rutaceae) nutrition and production.

Nitrogen, phosphorus and potassium dose effect in the graft box of lemon tree (of the family Rutaceae) nutrition and production. The aim of the study was to evaluate the graft box of lemon tree (of the family Rutaceae) nutritional state and its components of growth in function of nitrogen, phosphorus and potassium dose by fertilization. The experimental outlining was entirely made casually in factorial scheme 3(3) + 1, being 3 factors (nitrogen, phosphorus and potassium - NPK), 3 doses and in evidence (without fertilization), with 3 repetitions. The experimental milt was constituted by two tubes of 2,8 cm diameter and 12,3 cm high with a graft box (Hipobioto) of lemon tree (of the family Rutaceae) in each tube. The doses used were constituted by doses of N (460; 920 e 18,10 mg dm(-3)), P (50; 100 e 200 mg dm(-3)) and K (395; 790 e 1580 mg dm(-3)). The fertilization with N and K was carried out by fertirrigations and the P added to the substract of Pinus rind and vermiculite before the seeding. when the plants were 133 days after the germination they were subdivided in radicular system and air part for the determinations of the dry matter mass, height, foliar area, stem diameter and contents of nutrients. The N, K and P doses of 920 mg dm(-3), 790 mg dm(-3), 100 mg dm(-3), respectively, were enough for the suitable development of the graft box of lemon tree (of the family Rutaceae) in tubes.