Absence of Melatonin Induces Night-Time Hepatic Insulin Resistance and Increased Gluconeogenesis Due to Stimulation of Nocturnal Unfolded Protein Response

It is known that the circadian rhythm in hepatic phosphoenolpyruvate carboxykinase expression (a limiting catalytic step of gluconeogenesis) and hepatic glucose production is maintained by both daily oscillation in autonomic inputs to the liver and night feeding behavior. However, increased glycemia and reduced melatonin (Mel) levels have been recently shown to coexist in diabetic patients at the end of the night period. In parallel, pinealectomy (PINX) is known to cause glucose intolerance with increased basal glycemia exclusively at the end of the night. The mechanisms that underlie this metabolic feature are not completely understood. Here, we demonstrate that PINX rats show night-time hepatic insulin resistance characterized by reduced insulin-stimulated RAC-alpha serine/threonine-protein kinase phosphorylation and increased phosphoenolpyruvate carboxykinase expression. In addition, PINX rats display increased conversion of pyruvate into glucose at the end of the night. The regulatory mechanism suggests the participation of unfolded protein response (UPR), because PINX induces night-time increase in activating transcription factor 6 expression and prompts a circadian fashion of immunoglobulin heavy chain-binding protein, activating transcription factor 4, and CCAAT/enhancer-binding protein-homologous protein expression with Zenith values at the dark period. PINX also caused a night-time increase in Tribble 3 and regulatory-associated protein of mammalian target of rapamycin; both were reduced in liver of PINX rats treated with Mel. Treatment of PINX rats with 4-phenyl butyric acid, an inhibitor of UPR, restored night-time hepatic insulin sensitivity and abrogated gluconeogenesis in PINX rats. Altogether, the present data show that a circadian oscillation of UPR occurs in the liver due to the absence of Mel. The nocturnal UPR activation is related with night-time hepatic insulin resistance and increased gluconeogenesis in PINX rats. (Endocrinology 152: 1253-1263, 2011)

Are torque values of preadjusted brackets precise?

OBJECTIVE: The aim of the present study was to verify the torque precision of metallic brackets with MBT prescription using the canine brackets as the representative sample of six commercial brands. MATERIAL AND METHODS: Twenty maxillary and 20 mandibular canine brackets of one of the following commercial brands were selected: 3M Unitek, Abzil, American Orthodontics, TP Orthodontics, Morelli and Ortho Organizers. The torque angle, established by reference points and lines, was measured by an operator using an optical microscope coupled to a computer. The values were compared to those established by the MBT prescription. RESULTS: The results showed that for the maxillary canine brackets, only the Morelli torque (-3.33º) presented statistically significant difference from the proposed values (-7º). For the mandibular canines, American Orthodontics (-6.34º) and Ortho Organizers (-6.25º) presented statistically significant differences from the standards (-6º). Comparing the brands, Morelli presented statistically significant differences in comparison with all the other brands for maxillary canine brackets. For the mandibular canine brackets, there was no statistically significant difference between the brands. CONCLUSIONS: There are significant variations in torque values of some of the brackets assessed, which would clinically compromise the buccolingual positioning of the tooth at the end of orthodontic treatment.

Fracture resistance of weakened roots restored with composite resin and glass fiber post

This study evaluated the fracture resistance of weakened roots restored with glass fiber posts, composite resin cores and complete metal crowns. Thirty maxillary canines were randomly divided into 3 groups of 10 teeth each: teeth without weakened roots (control); teeth with partially weakened roots (PWR) and teeth with and largely weakened roots (LWR). The control group was restored with glass fiber posts and a composite resin core. Teeth in the PWR and LWR groups were flared internally to standardized dimensions in order to simulate root weakness. Thereafter, the roots were partially filled with composite resin and restored in the same way as in the control group. The specimens were exposed to 250,000 cycles in a controlled chewing simulator. All intact specimens were subjected to a static load (N) in a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed by one-way ANOVA and Dunnett's test for multiple comparisons (p=0.05). There were statistically significant difference differences (p<0.01) among the groups (control group = 566.73 N; PWR = 409.64 N; and LWR = 410.91 N), with significantly higher fracture strength for the control group. There was no statistically significant difference (p>0.05) between the weakened groups. The results of this study showed that thicker root dentin walls significantly increase the fracture resistance of endodontically treated teeth.

Effect of different ferrule designs on the fracture resistance and failure pattern of endodontically treated teeth restored with fiber posts and all-ceramic crowns

OBJECTIVE: This study investigated the effect of different ferrule heights on endodontically treated premolars. MATERIAL AND METHODS: Fifty sound mandibular first premolars were endodontically treated and then restored with 7-mm fiber post (FRC Postec Plus #1 Ivoclar-Vivadent) luted with self-polymerized resin cement (Multilink, Ivoclar Vivadent) while the coronal section was restored with hybrid composite core build-up material (Tetric Ceram, Ivoclar-Vivadent), which received all-ceramic crown. Different ferrule heights were investigated: 1-mm circumferential ferrule without post and core (group 1 used as control), a circumferential 1-mm ferrule (group 2), non-uniform ferrule 2-mm buccally and 1-mm lingually (group 3), non-uniform ferrule 3-mm buccally and 2-mm lingually (group 4), and finally no ferrule preparation (group 5). The fracture load and failure pattern of the tested groups were investigated by applying axial load to the ceramic crowns (n=10). Data were analyzed statistically by one-way ANOVA and Tukey's post-hoc test was used for pair-wise comparisons (α=0.05). RESULTS: There were no significant differences among the failure load of all tested groups (P<0.780). The control group had the lowest fracture resistance (891.43±202.22 N) and the highest catastrophic failure rate (P<0.05). Compared to the control group, the use of fiber post reduced the percentage of catastrophic failure while increasing the ferrule height did not influence the fracture resistance of the restored specimens. CONCLUSIONS: Within the limitations of this study, increasing the ferrule length did not influence the fracture resistance of endodontically treated teeth restored with glass ceramic crowns. Insertion of a fiber post could reduce the percentage of catastrophic failure of these restorations under function.

Shear bond strength of self-etch and total-etch bonding systems at different dentin depths

The purpose of this study was to evaluate the dentin shear bond strength of four adhesive systems (Adper Single Bond 2, Adper Prompt L-Pop, Magic Bond DE and Self Etch Bond) in regards to buccal and lingual surfaces and dentin depth. Forty extracted third molars had roots removed and crowns bisected in the mesiodistal direction. The buccal and lingual surfaces were fixed in a PVC/acrylic resin ring and were divided into buccal and lingual groups assigned to each selected adhesive. The same specimens prepared for the evaluation of superficial dentin shear resistance were used to evaluate the different depths of dentin. The specimens were identified and abraded at depths of 0.5, 1.0, 1.5 and 2.0 mm. Each depth was evaluated by ISO TR 11405 using an EMIC-2000 machine regulated at 0.5 mm/min with a 200 Kgf load cell. We performed statistical analyses on the results (ANOVA, Tukey and Scheffé tests). Data revealed statistical differences (p < 0.01) in the adhesive and depth variation as well as adhesive/depth interactions. The Adper Single Bond 2 demonstrated the highest mean values of shear bond strength. The Prompt L-Pop product, a self-etching adhesive, revealed higher mean values compared with Magic Bond DE and Self Etch Bond adhesives, a total and self-etching adhesive respectively. It may be concluded that the shear bond strength of dentin is dependent on material (adhesive system), substrate depth and adhesive/depth interaction.

Isolation of extraintestinal pathogenic Escherichia coli from diarrheic dogs and their antimicrobial resistance profile

From January to December 2006, 92 Escherichia coli isolates from 25 diarrheic dogs were analyzed by screening for the presence of adhesin-encoding genes (pap, sfa, afa), hemolysin and aerobactin genes. Virulence gene frequencies detected in those isolates were: 12% pap, 1% sfa, 10% hemolysin and 6.5% aerobactin. Ten isolates were characterized as extraintestinal pathogenic E. coli (ExPEC) strains; all showed a multidrug resistance phenotype that may represent a reason for concern due the risk of dissemination of antimicrobial resistant genes to the microbiota of human beings.

Influence of sodium hypochlorite and edta on the microtensile bond strength of a self-etching adhesive system

Chemical substances used during biomechanical preparation of root canals can alter the composition of dentin surface and affect the interaction with restorative materials. OBJECTIVE: The purpose of this study was to evaluate the microtensile bond strength (µTBS) of a self-etching adhesive system to dentin irrigated with sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA). MATERIAL AND METHODS: Thirty human third molars were sectioned 3 mm below the occlusal surface, polished with 600- to 1200-grit silicon carbide papers, and randomly divided into 3 groups: G1 (control): no irrigating solution; G2: 1% NaOCl; and G3: 1% NaOCl followed by the application of 17% EDTA. The specimens received the self-etching adhesive system (XENO III - Dentsply), restored with microhybrid composite resin (Z250 - 3M ESPE), sectioned and trimmed to create 4 hourglass-shaped slabs of each tooth. The slabs were tested in microtensile strength in a universal testing machine (Emic DL 2000) at a crosshead speed of 0.5 mm/min until fracture. The results were analyzed statistically by ANOVA and Newman-Keuls test. RESULTS: Mean µTBS values and standard deviations in MPa were: G1 = 11.89 ± 4.22; G2 = 19.41 ± 5.32; G3 = 11.34 ± 4.73. 1% NaOCl increased the adhesive resistance significantly (p<0.001/F=22.5763). The application of 1% NaOCl/17% EDTA resulted in statistically similar µTBS to the control group. CONCLUSIONS: None of the irrigants affected negatively the µTBS of XENO III to dentin. The use of 1% NaOCl alone resulted in higher bond strength than the other treatments. The combination of 1% NaOCl and 17% EDTA produced similar bond strength to that of untreated dentin.

Rates of antimicrobial resistance in latin america (2004-2007) and in vitro activity of the glycylcycline tigecycline and of other antibiotics

As a part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.), Gram-positive and Gram-negative bacterial isolates were collected from 33 centers in Latin America (centers in Argentina, Brazil, Chile, Colombia, Guatemala, Honduras, Jamaica, Mexico, Panama, Puerto Rico, and Venezuela) from January 2004 to September 2007. Argentina and Mexico were the greatest contributors of isolates to this study. Susceptibilities were determined according to Clinical Laboratory Standards Institute guidelines. Resistance levels were high for most key organisms across Latin America: 48.3% of Staphylococcus aureus isolates were methicillin-resistant while 21.4% of Acinetobacter spp. isolates were imipenem-resistant. Extended-spectrum β-lactamase were reported in 36.7% of Klebsiella pneumoniae and 20.8% of E. coli isolates. Tigecycline was the most active agent against Gram-positive isolates. Tigecycline was also highly active against all Gram-negative organisms, with the exception of Pseuodomonas aeruginosa, against which piperacillin-tazobactam was the most active agent tested (79.3% of isolates susceptible). The in vitro activity of tigecycline against both Gram-positive and Gram-negative isolates indicates that it may be an useful tool for the treatment of nosocomial infections, even those caused by organisms that are resistant to other antibacterial agents.

Dosimetria esporular: Bacillus subtilis TKJ6312 como biossensor de radiação solar biologicamente ativa

Since 2000, spore dosimetry and spectral photometry have been performed in parallel at the Southern Space Observatory, São Martinho da Serra (Southern Brazil). A comparative study involving data from Punta Arenas - Chile (53.2º S), São Martinho da Serra (29.5º S), Padang - Indonesia (0.9ºS), Brussels - Belgium (50.9º N) and Kiyotake - Japan (31.9º N) from 2000 to 2006 is presented. The Spore Inactivation Doses presented the higher values in summer (973 ± 73 for Punta Arenas and 4,369 ± 202 for São Martinho da Serra, as well 1,402 ± 170 and 3,400 ± 1,674 for Brussels and Kiyotake, respectively). The simplicity, robustness and high resistance of bacterial spores makes the biosensor an potential biological tool for UV-B monitoring.

Wettability, Shrinkage and Color Changes of Araucaria angustifolia After Heating Treatment

The effects of thermal treatment on the wettability and shrink resistance of Araucaria angustifolia (Parana pine) were studied from 20 to 200 °C. The contact angles of water droplets on untreated and heat-treated samples were measured by the sessile drop method in the grain of heartwood and sapwood cut in the radial, longitudinal, and tangential directions. A significant increase of the contact angles was verified for the samples from room temperature to 120 °C, in particular in the radial and tangential directions; at higher temperatures, the contact angles assumed almost constant values. From 120 to 200 °C, the sapwood of Araucaria angustifolia showed better dimensional stability and lower thermal resistance when compared to the heartwood. Variations of color were also studied by using the CIELab system, which showed to be capable of accurately distinguishing samples treated at different temperatures.

Análise de diferentes medidas antropométricas na identificação de síndrome metabólica, com ou sem alteração do metabolismo glicídico

OBJETIVO: Este estudo comparou parâmetros antropométricos e de resistência à insulina de indivíduos sem e com síndrome metabólica (SM), subestratificados pela presença de anormalidades glicêmicas. SUJEITOS E MÉTODOS: Foram incluídos 454 indivíduos (66% mulheres, 54% brancos), sendo 155 alocados para o grupo 1 (sem SM, sem anormalidade glicêmica), 32 para o grupo 2 (sem SM, com anormalidade glicêmica), 104 no grupo 3 (com SM, sem anormalidade glicêmica) e 163 no grupo 4 (com SM e anormalidade glicêmica). Os grupos foram comparados por ANOVA. RESULTADOS: Os grupos com SM (3 e 4) apresentaram os piores perfis antropométrico e lipídico; no grupo 2, apesar de glicemias significantemente mais elevadas, as médias das variáveis antropométricas e lipídicas não diferiram do grupo 1. Os maiores valores médios de HOMA-IR foram encontrados nos grupos com SM, enquanto o grupo 2 apresentou o menor HOMA-β. A trigliceridemia foi a variável metabólica com coeficientes de correlação mais elevados com a antropometria. Porém, as correlações mais fortes foram da circunferência da cintura (r = 0,503) e da razão cintura-altura (r = 0,513) com o HOMA-IR (p < 0,01). CONCLUSÃO: Nossos achados revelam que, em amostra da população brasileira, qualquer das medidas antropométricas identifica indivíduos com SM, mas não parece capaz de diferenciar aqueles com distúrbio glicêmico. Reforçamos a relação mais forte das medidas de adiposidade central com resistência à insulina, sugerindo utilidade da razão cintura-altura. É possível que componente autoimune contribua para o comprometimento do metabolismo glicídico dos indivíduos do grupo 2.

Redução da pressão arterial e do duplo produto de repouso após treinamento resistido em idosas hipertensas

FUNDAMENTO: Em razão das controvérsias existentes na literatura quanto aos possíveis benefícios do treinamento resistido (TR) sobre a pressão arterial de repouso (PA) e por causa da escassez de estudos com indivíduos idosos e hipertensos, o TR é pouco recomendado como forma de tratamento não-farmacológico da hipertensão arterial. OBJETIVO: Verificar os efeitos do TR progressivo sobre a pressão arterial de repouso (PA), a freqüência cardíaca (FC) e o duplo produto (DP) em idosas hipertensas controladas. MÉTODOS: Vinte mulheres idosas (66,8 ± 5,6 anos de idade) sedentárias, controladas com medicação anti-hipertensiva, realizaram 12 semanas de TR, compondo o grupo do treinamento resistido (GTR). Vinte e seis idosas (65,3 ± 3,4 anos de idade) hipertensas controladas não realizaram exercícios físicos durante a pesquisa, constituindo o grupo-controle. RESULTADOS: Houve redução significativa nos valores de repouso da pressão arterial sistólica (PAS), da pressão arterial média (PAM) e do DP após o TR. Não foram encontradas reduções significativas na pressão arterial diastólica (PAD) e na FC de repouso após o TR em ambos os grupos. A magnitude da queda no GTR foi de 10,5 mmHg, 6,2 mmHg e 2.218,6 mmHg x bpm para a PAS, PAM e o DP, respectivamente. CONCLUSÃO: O TR progressivo reduziu a PAS, PAM e o DP de repouso de idosas hipertensas, controladas com medicação anti-hipertensiva.

The relationship between cortisol concentrations in pregnancy and systemic vascular resistance in childhood

Objective. To assess the relationship between cortisol concentrations in the last trimester of pregnancy and systemic vascular resistance — SVR in childhood. Materials and methods. This study is part of a cohort involving 130 Brazilian pregnant women and their children, ages 5 to 7 years. Maternal cortisol was determined in saliva by an enzyme immunoassay utilizing the mean concentration of 9 samples of saliva (3 in each different day), collected at the same time, early in the morning. SVR was assessed by the HDI/PulseWave CR-2000 Cardiovascular Profiling System®. Socioeconomic and demographic characteristics and life style factors were determined by a questionnaire. The nutritional status of the women and children was assessed by the body mass index — BMI. The association between maternal cortisol and SVR in childhood was calculated by multivariate linear regression analysis. Results.There were statistically significant associations between maternal cortisol and SVR (p = 0.043) and BMI-z score of the children (p = 0.027), controlling for maternal BMI, birth weight, age, and gender of the children. Conclusion. As far as we know this is the first study in the literature assessing the association between cortisol concentrations in pregnancy and SVR in childhood. Overall, the data suggest that exposure to excess glucocorticoid in the prenatal period is associated to vascular complications in childhood, predisposing to cardiovascular diseases in later life

The relationship between birth weight and insulin resistance in childhood

Chronic diseases that are typical of adulthood may originate in intra-uterine life through inadequate fetal development. The present epidemiological cohort study of 506 healthy children aged 5\20138 years evaluated the relationship between birth weight and insulin resistance in an age group that has been assessed in few similar studies. Insulin concentration was determined by chemiluminescence and insulin resistance by the homeostasis model assessment (HOMA). Blood glucose, total cholesterol and fractions (LDL cholesterol and HDL cholesterol) and TAG concentrations were determined by automated enzymatic methods. Linear regression analysis investigated the relationship between birth weight (assessed as a continuous variable and in three categories: small for gestational age, SGA; adequate for gestational age and large for gestational age) and the HOMA index, using backward stepwise selection and biological models to explain the causal pathway of the relationship. There were negativeassociations between birth weight (P < 0·001), SGA (P = 0·027) and the HOMA index, and a positive association between waist circumference (P < 0·001) and the HOMA index. Considering the significant associations between birth weight and waist circumference (P < 0·001) and waist circumference and insulin resistance (P < 0·001), we can probably suspect that lower birth weight is a common cause of higher waist circumference and insulin resistance. In summary, the results of the present study showed increased insulin resistance in apparently healthy, young children, who had lower weight at birth and higher measurements of waist circumference. There is a need to develop public health policies that adopt preventive measures to promote adequate maternal-fetal and child development and enable early diagnosis of metabolic abnormalities

Relationship between training status and maximal fat oxidation rate

This study aimed to compare maximal fat oxidation rate parameters between moderate-and low-performance runners. Eighteen runners performed an incremental treadmill test to estimate individual maximal fat oxidation rate (Fat(max)) based on gases measures and a 10,000-m run on a track. The subjects were then divided into a low and moderate performance group using two different criteria: 10,000-m time and VO(2)max values. When groups were divided using 10,000-m time, there was no significant difference in Fat(max) (0.41 +/- 0.16 and 0.27 +/- 0.12 g.min(-1), p = 0.07) or in the exercise intensity that elicited Fat(max) (59.9 +/- 16.5 and 68.7 +/- 10.3 % (V) over dotO(2max), p = 0.23) between the moderate and low performance groups, respectively (p > 0.05). When groups were divided using VO(2max) values, Fat(max) was significantly lower in the low VO(2max) group than in the high VO(2max) group (0.29 +/- 0.10 and 0.47 +/- 0.17 g.min(-1), respectively, p < 0.05) but the intensity that elicited Fat(max) did not differ between groups (64.4 +/- 14.9 and 61.6 +/- 15.4 % VO(2max)). Fat(max) or % VO(2max) that elicited Fat(max) was not associated with 10,000 m time. The only variable associated with 10,000-m running performance was % VO(2max) used during the run (p < 0.01). In conclusion, the criteria used for the division of groups according to training status might influence the identification of differences in Fat(max) or in the intensity that elicits Fat(max).