The Calcium-Sensing Receptor Increases Activity of the Renal NCC through the WNK4-SPAK Pathway.

Background Hypercalciuria can result from activation of the basolateral calcium-sensing receptor (CaSR), which in the thick ascending limb of Henle's loop controls Ca2+ excretion and NaCl reabsorption in response to extracellular Ca2+ However, the function of CaSR in the regulation of NaCl reabsorption in the distal convoluted tubule (DCT) is unknown. We hypothesized that CaSR in this location is involved in activating the thiazide-sensitive NaCl cotransporter (NCC) to prevent NaCl loss.Methods We used a combination of in vitro and in vivo models to examine the effects of CaSR on NCC activity. Because the KLHL3-WNK4-SPAK pathway is involved in regulating NaCl reabsorption in the DCT, we assessed the involvement of this pathway as well.Results Thiazide-sensitive 22Na+ uptake assays in Xenopus laevis oocytes revealed that NCC activity increased in a WNK4-dependent manner upon activation of CaSR with Gd3+ In HEK293 cells, treatment with the calcimimetic R-568 stimulated SPAK phosphorylation only in the presence of WNK4. The WNK4 inhibitor WNK463 also prevented this effect. Furthermore, CaSR activation in HEK293 cells led to phosphorylation of KLHL3 and WNK4 and increased WNK4 abundance and activity. Finally, acute oral administration of R-568 in mice led to the phosphorylation of NCC.Conclusions Activation of CaSR can increase NCC activity via the WNK4-SPAK pathway. It is possible that activation of CaSR by Ca2+ in the apical membrane of the DCT increases NaCl reabsorption by NCC, with the consequent, well known decrease of Ca2+ reabsorption, further promoting hypercalciuria.

Clofibrate Treatment Decreases Inflammation and Reverses Myocardial Infarction-Induced Remodelation in a Rodent Experimental Model.

Myocardial infarction (MI) initiates an inflammatory response that promotes both beneficial and deleterious effects. The early response helps the myocardium to remove damaged tissue; however, a prolonged later response brings cardiac remodeling characterized by functional, metabolic, and structural pathological changes. Current pharmacological treatments have failed to reverse ischemic-induced cardiac damage. Therefore, our aim was to study if clofibrate treatment was capable of decreasing inflammation and apoptosis, and reverse ventricular remodeling and MI-induced functional damage. Male Wistar rats were assigned to (1) Sham coronary artery ligation (Sham) or (2) Coronary artery ligation (MI). Seven days post-MI, animals were further divided to receive vehicle (V) or clofibrate (100 mg/kg, C) for 7 days. The expression of IL-6, TNF-α, and inflammatory related molecules ICAM-1, VCAM-1, MMP-2 and -9, nuclear NF-kB, and iNOS, were elevated in MI-V. These inflammatory biomarkers decreased in MI-C. Also, apoptotic proteins (Bax and pBad) were elevated in MI-V, while clofibrate augmented anti-apoptotic proteins (Bcl-2 and 14-3-3ε). Clofibrate also protected MI-induced changes in ultra-structure. The ex vivo evaluation of myocardial functioning showed that left ventricular pressure and mechanical work decreased in infarcted rats; clofibrate treatment raised those parameters to control values. Echocardiogram showed that clofibrate partially reduced LV dilation. In conclusion, clofibrate decreases cardiac remodeling, decreases inflammatory molecules, and partly preserves myocardial diameters.

Auxin analysis using laser microdissected plant tissues sections.

BACKGROUND: Quantitative measurement of actual auxin levels in plant tissue is complimentary to molecular methods measuring the expression of auxin related genes. Current analytical methods to quantify auxin have pushed the limit of detection to where auxin can be routinely quantified at the pictogram (pg) level, reducing the amount of tissue needed to perform these kinds of studies to amounts never imagined a few years ago. In parallel, the development of technologies like laser microdissection microscopy (LMD) has allowed specific cells to be harvested from discrete tissues without including adjacent cells. This method has gained popularity in recent years, especially for enabling a higher degree of spatial resolution in transcriptome profiling. As with other quantitative measurements, including hormone quantifications, sampling using traditional LMD is still challenging because sample preparation clearly compromises the preservation of analytes. Thus, we have developed and validated a sample preparation protocol combining cryosectioning, freeze-drying, and capturing with a laser microdissection microscope to provide high-quality and well-preserved plant materials suitable for ultrasensitive, spatially-resolved auxin quantification. RESULTS: We developed a new method to provide discrete plant tissues for indole-3-acetic acid (IAA) quantification while preserving the plant tissue in the best possible condition to prevent auxin degradation. The method combines the use of cryosectioning, freeze-drying and LMD. The protocol may also be used for other applications that require small molecule analysis with high tissue-specificity where degradation of biological compounds may be an issue. It was possible to collect the equivalent to 15 mg of very specific tissue in approximately 4 h using LMD. CONCLUSIONS: We have shown, by proof of concept, that freeze dried cryosections of plant tissue were suitable for LMD harvest and quantification of the phytohormone auxin using GC-MS/MS. We expect that the ability to resolve auxin levels with both spatial- and temporal resolution with high accuracy will enable experiments on complex processes, which will increase our knowledge of the many roles of auxins (and, in time, other phytohormones) in plant development.

Preclinical Biokinetic Modelling of Tc-99m Radiophamaceuticals Obtained from Semi-Automatic Image Processing.

The aim of this study was to develop a semi automatic image processing algorithm (AIPA) based on the simultaneous information provided by X-ray and radioisotopic images to determine the biokinetic models of Tc-99m radiopharmaceuticals from quantification of image radiation activity in murine models. These radioisotopic images were obtained by a CCD (charge couple device) camera coupled to an ultrathin phosphorous screen in a preclinical multimodal imaging system (Xtreme, Bruker). The AIPA consisted of different image processing methods for background, scattering and attenuation correction on the activity quantification. A set of parametric identification algorithms was used to obtain the biokinetic models that characterize the interaction between different tissues and the radiopharmaceuticals considered in the study. The set of biokinetic models corresponded to the Tc-99m biodistribution observed in different ex vivo studies. This fact confirmed the contribution of the semi-automatic image processing technique developed in this study.

DNase concentration assay to obtain DNA-free RNA from sugarcane leaves.

The success of gene expression studies, protein synthesis, and construction of cDNA libraries directly depends on the purity and integrity of the RNA used in these tests, as even minor amounts of contaminant DNA (<1%) can produce a false positive amplification signal in quantitative real-time PCR. For RNA contaminated with genomic DNA, an essential step in the studies on gene expression is the treatment of the RNA samples with DNase. This study was conducted to test three different concentrations of DNase I (0.02, 0.04, and 0.06 µL/​​ng of RNA), which were chosen based on the results of the RNA sample quantifications and as indicated by the manufacturer, to digest genomic DNA present in the RNA samples extracted from sugarcane leaves with the Concert™ Plant RNA Reagent. The results showed that all three concentrations of DNase significantly reduced DNA concentrations. However, RNA was also degraded on DNase I treatment. In addition, the amount of DNA present in the RNA samples after purification with DNase I was sufficient for its amplification in the tests conducted with conventional PCR. Furthermore, the condition of RNA samples obtained after the treatments allowed for real-time PCR. Therefore, we concluded that 0.02 µL DNase I was the ideal concentration for sugarcane RNA purification, as higher concentrations do not increase the efficiency of the genomic DNA digestion in RNA samples and only make the purification process more expensive. This study provides important information on the effect of high concentrations of DNase I and complements previous studies that have so far tested only the DNase concentration recommended by the manufacturer.

PPARα Stimulation Modulates Myocardial Ischemia-induced Activation of Renin-Angiotensin System.

We have recently demonstrated that peroxisome proliferator-activated receptor alpha (PPARα) stimulation lowers the production of angiotensin II while increasing the production of Ang-(1-7), both in cardiac and plasmatic level. This stimulation improves nitric oxide bioavailability, preserving cardiac histologic features and functioning. Based on these results, we decided to study the effect of PPARα stimulation on renin-angiotensin system components of ischemic myocardium. Male Wistar rats (weighing 300-350 g) were assigned to the following groups: (1) sham, (2) myocardial ischemia vehicle-treated (MI-V), and (3) myocardial ischemia clofibrate-treated. Expression of the angiotensin-converting enzyme increased during ischemia, whereas clofibrate-treated group remained comparable to control. Activation of the PPARα receptor stimulated the expression of angiotensin-converting enzyme-2; while the activity of this enzyme was increased in MI-V, clofibrate inhibited any change. The concentration of bradykinin and phospho-Akt(SER473) in homogenate increased in the animals treated with the drug. Mas receptor expression increased in MI-V rats. In conclusion, stimulation of PPARα by clofibrate prevents an increase in the activity of renin-angiotensin system and promotes the production of vasodilator substances.

Molecular characterization of accessions of Cratylia argentea (Camaratuba) using ISSR markers.

Cratylia argentea (Desv.) Kuntze (Fabaceae) is a drought-tolerant, perennial legume found primarily in Brazil, Bolivia, and Peru. The shrub is well adapted to acid soils and exhibits high productivity and nutritional value, characteristics that would favor its use as a dry season animal forage supplement in semiarid regions. In plant improvement programs, the production of elite hybrids with superior traits is generally achieved by crossing parents that exhibit the highest level of genetic divergence. Therefore, the aim of the present study was to assess genetic diversity among 13 accessions of C. argentea from the same population maintained in the active germplasm bank of Embrapa Meio-Norte using inter-simple sequence repeat (ISSR) markers. Genetic similarities between C. argentea accessions were estimated from Jaccard coefficients, and a dendrogram was constructed using the unweighted pair group method with arithmetic average (UPGMA). The set of 15 primers selected for ISSR analysis generated a total of 313 loci of which 79.23% were polymorphic. The mean number of bands per primer was 20.87, and the amplicons ranged from 280 to 3000 bp in size. Primers UBC834 and UBC827 generated the largest number of polymorphic loci and exhibited 90.91 and 100% polymorphism, respectively. The coefficients of genetic similarity among accessions varied between 0.49 and 0.73. UPGMA cluster analysis allowed the identification of four genotypic groups and demonstrated the existence of considerable variability within the collection. Potential progenitors were selected that would offer good possibilities of obtaining unusual and favorable combinations of genes in a plant breeding program.

Randomized, double-blind, multicenter safety and efficacy study of rifalazil compared with azithromycin for treatment of uncomplicated genital Chlamydia trachomatis infection in women.

A randomized, double-blind study comparing single-dose chlamydia therapies of oral rifalazil (25 mg) and azithromycin (1 g) was conducted in 82 women with uncomplicated genital Chlamydia trachomatis infection. The microbiologic cure rate of C. trachomatis with rifalazil (n = 33) was 84.8% at the visit on day 22 to 26 (test-of-cure visit), versus 92.1% with azithromycin (n = 38), and the number of treatment failures in each group was 5 and 3, respectively. The difference in cure rate was -7.3%, with a lower limit of the 95% confidence interval (95% CI) of -22.5, and thus, noninferiority was not established at the prespecified margin (lower limit of CI of -15%). The overall treatment-emergent adverse event (TEAE) and treatment-related TEAE rates were lower in the rifalazil group (68% and 55%) than in the azithromycin group (71% and 62%), respectively. Subjects classified as treatment failures at day 22 to 26 had a lower mean plasma concentration of rifalazil at the visit on day 8 to 12 than those classified as treatment cures, but this difference was not significant; however, the levels were similar for both groups at the visit on day 22 to 26. A single 25-mg dose of rifalazil was well tolerated and eradicated C. trachomatis in most of these women with uncomplicated genital C. trachomatis infection. (The study was registered at clinicaltrials.gov under registration no. NCT01631201).

ACE inhibitors and their interaction with systems and molecules involved in metabolism.

The main function of the renin-angiotensin-aldosterone system (RAAS) is the regulation of blood pressure; therefore, researchers have focused on its study to treat cardiovascular and renal diseases. One of the most widely used treatments derived from the study of RAAS, is the use of angiotensin-converting enzyme inhibitors (ACEi). Since it was discovered, the main target of ACEi has been the cardiovascular and renal systems. However, being the RAAS expressed locally in several specialized tissues and cells such as pneumocytes, hepatocytes, spleenocytes, enterocytes, adipocytes, and neurons the effect of inhibitors has expanded, because it is expected that RAAS has a role in the specific function of those cells. Many chronic degenerative diseases compromise the correct function of those organs, and in most of them, the RAAS is overactivated. Therefore, the use of ACEi must exert a benefit on an impaired system. Accordingly, the objective of this review is to present a brief overview of the cardiovascular and renal actions of ACEi and its effects in organs that are not the classic targets of ACEi that carry on glucose and lipid metabolism.

Reversion of steatosis by SREBP-1c antisense oligonucleotide did not improve hepatic insulin action in diet-induced obesity mice.

The literature has associated hepatic insulin action with NAFLD. In this sense, treatments to revert steatosis and improve hepatic insulin action become important. Our group has demonstrated that inhibition of Sterol Regulatory Element Binding Proteins-1c (SREBP-1c) reverses hepatic steatosis. However, insulin signals after NAFLD reversion require better investigation. Thus, in this study, we investigated if the reversal of NAFLD by SREBP-1c inhibitor results in improvement in the hepatic insulin signal in obesity mice. After installation/achievement of diet-induced obesity and insulin resistance, Swiss mice were divided into 3 groups: i) Lean, ii) D-IHS, diet-induced hepatic steatosis [no treatment with antisense oligonucleotide (ASO)], and iii) RD-IHS, reversion of diet-induced hepatic steatosis (treated with ASO). The mice were treated with ASO SREBP-1c as previously described by our group. After ASO treatment, one set of animals was anesthetized and used for in vivo test, and another mice set was anesthetized and used for histology and Western blot analysis. Reversion of diet-induced hepatic steatosis did not change blood glucose, glucose decay constant (k(ITT)), body weight, or serum insulin levels. In addition, results showed that the protocol did not improve insulin pathway signaling, as confirmed by the absence of changes in IR, IRS1, Akt and Foxo1 phosphorylation in hepatic tissue. In parallel, no alterations were observed in proinflammatory molecules. Thus, our results suggest that the inhibition of SREBP-1c reverts steatosis, but without improving insulin hepatic resistance.

Tramadol hydrochloride extended-release once-daily in the treatment of osteoarthritis of the knee and/or hip: a double-blind, randomized, dose-ranging trial.

This 12-week, multicenter, randomized, double-blind, placebo-controlled, dose-ranging trial evaluated tramadol ER (extended-release tramadol) in the management of osteoarthritis pain. Adults with knee and/or hip osteoarthritis and baseline pain intensity of ≥40 on a 100-mm visual analog scale (0 = no pain, 100 = extreme pain) received once-daily tramadol ER 100 mg (n = 201), 200 mg (n = 199), or 300 mg (n = 199), celecoxib 200 mg (n = 202; to test model sensitivity), or placebo (n = 200). Coprimary efficacy variables were Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale, WOMAC physical function subscale, and patient global assessment of disease activity. Tramadol ER 300 mg significantly improved patient global assessment scores compared with placebo (P ≤ 0.05), but not the other 2 coprimary efficacy variables. Tramadol ER 200 and 100 mg were not significantly different from placebo for the coprimary efficacy variables. Daily diary arthritis pain intensity scores improved significantly for tramadol ER 300 and 200 mg compared with placebo. WOMAC joint stiffness subscale, physician's global assessment, arthritis pain intensity in index and nonindex joints, and overall sleep quality scores improved significantly for tramadol ER 300 mg compared with placebo. Significant differences in efficacy between celecoxib and placebo validated the model sensitivity. Adverse events occurred more frequently with tramadol ER than placebo in the gastrointestinal (nausea, constipation, diarrhea) and central nervous (dizziness, headache) systems. In this study, tramadol ER 300 mg was effective in the management of moderate to severe painful osteoarthritis of the hip or knee. A large, increasing placebo response during the study may have contributed to the lack of statistical separation between tramadol ER 200 or 100 mg and placebo.

Fenofibrate Protects Cardiomyocytes from Hypoxia/Reperfusion- and High Glucose-Induced Detrimental Effects.

Lesions caused by high glucose (HG), hypoxia/reperfusion (H/R), and the coexistence of both conditions in cardiomyocytes are linked to an overproduction of reactive oxygen species (ROS), causing irreversible damage to macromolecules in the cardiomyocyte as well as its ultrastructure. Fenofibrate, a peroxisome proliferator-activated receptor alpha (PPARα) agonist, promotes beneficial activities counteracting cardiac injury. Therefore, the objective of this work was to determine the potential protective effect of fenofibrate in cardiomyocytes exposed to HG, H/R, and HG+H/R. Cardiomyocyte cultures were divided into four main groups: (1) control (CT), (2) HG (25 mM), (3) H/R, and (4) HG+H/R. Our results indicate that cell viability decreases in cardiomyocytes undergoing HG, H/R, and both conditions, while fenofibrate improves cell viability in every case. Fenofibrate also decreases ROS production as well as nicotinamide adenine dinucleotide phosphate oxidase (NADPH) subunit expression. Regarding the antioxidant defense, superoxide dismutase (SOD Cu2+/Zn2+ and SOD Mn2+), catalase, and the antioxidant capacity were decreased in HG, H/R, and HG+H/R-exposed cardiomyocytes, while fenofibrate increased those parameters. The expression of nuclear factor erythroid 2-related factor 2 (Nrf2) increased significantly in treated cells, while pathologies increased the expression of its inhibitor Keap1. Oxidative stress-induced mitochondrial damage was lower in fenofibrate-exposed cardiomyocytes. Endothelial nitric oxide synthase was also favored in cardiomyocytes treated with fenofibrate. Our results suggest that fenofibrate preserves the antioxidant status and the ultrastructure in cardiomyocytes undergoing HG, H/R, and HG+H/R preventing damage to essential macromolecules involved in the proper functioning of the cardiomyocyte.

The gut microbiota and its relationship with chronic kidney disease.

Chronic kidney disease (CKD) is a worldwide health problem, because it is one of the most common complications of metabolic diseases including obesity and type 2 diabetes. Patients with CKD also develop other comorbidities, such as hypertension, hyperlipidemias, liver and cardiovascular diseases, gastrointestinal problems, and cognitive deterioration, which worsens their health. Therapy includes reducing comorbidities or using replacement therapy, such as peritoneal dialysis, hemodialysis, and organ transplant. Health care systems are searching for alternative treatments for CKD patients to mitigate or retard their progression. One new topic is the study of uremic toxins (UT), which are excessively produced during CKD as products of food metabolism or as a result of the loss of renal function that have a negative impact on the kidneys and other organs. High urea concentrations significantly modify the microbiota in the gut also, cause a decrease in bacterial strains that produce anti-inflammatory and fuel molecules and an increase in bacterial strains that can metabolize urea, but also produce UT, including indoxyl sulfate and p-cresol sulfate. UT activates several cellular processes that induce oxidative environments, inflammation, proliferation, fibrosis development, and apoptosis; these processes mainly occur in the gut, heart, and kidney. The study of the microbiota during CKD allowed for the implementation of therapy schemes to try to reduce the circulating concentrations of UT and reduce the damage. The objective of this review is to show an overview to know the main UT produced in end-stage renal disease patients, and how prebiotics and probiotics intervention acts as a helpful tool in CKD treatment.

Low-dose estradiol spray to treat vasomotor symptoms: a randomized controlled trial.

OBJECTIVE: To investigate the safety and efficacy of a transdermal estradiol (E2) spray in women with postmenopausal vasomotor symptoms. METHOD: A randomized, double-blind, placebo-controlled, multicenter, parallel-group clinical trial was conducted. Postmenopausal women (N=454) with at least eight moderate-to-severe hot flushes per day applied daily, one, two, or three E2 (90 microliter spray contains 1.53 mg E2) or matching placebo sprays. The primary efficacy endpoints were mean change from baseline in frequency and severity of moderate-to-severe hot flushes at weeks 4 and 12. RESULTS: All three E2 groups showed a significant decrease in hot flushes at weeks 4 and 12 compared with their placebo groups (P<.010). The mean change in frequency at week 12 was eight fewer flushes per day for women in the E2 groups and between four and six fewer flushes for women in the placebo groups. Women in the three- and two-E2 spray groups demonstrated significant (P<.050) reductions in severity score at weeks 4 and 12; women in the one-spray group showed significant reductions at week 5. At week 12, the majority (74-85%) of women on E2 showed at least a 50% hot flush frequency reduction as compared with 46% in the placebo group. The systemic E2 delivery rates at week 12 were approximately 0.021 mg/d, 0.029 mg/d, and 0.040 mg/d for the one-, two-, and three-spray doses, respectively. Common adverse events were similar to those previously reported with other transdermal products. Treatment-related application site reaction rate was similar to placebo (1.3% compared with 1.8%). CONCLUSION: The three dose levels of E2 spray achieved efficacy at 0.021-0.040 mg/d delivery rates. The spray is a well-tolerated, new, convenient method of delivering low-dose E2 transdermally. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00122200. LEVEL OF EVIDENCE: I.

Disruption of the with no lysine kinase-STE20-proline alanine-rich kinase pathway reduces the hypertension induced by angiotensin II.

OBJECTIVE: The hypertensive effect of angiotensin II (AngII), a peptide hormone, is dependent on its intrarenal actions and the activation of the renal Na-Cl cotransporter (NCC), by AngII requires integrity of the with no lysine kinase/STE20-proline alanine-rich kinase (WNK/SPAK) signaling pathway. Here, we analyzed if the integrity of the WNK/SPAK pathway is required for AngII infusion to induce arterial hypertension. METHODS: We tested the effect of AngII or aldosterone administration on the blood pressure and on pNCC/NCC ratio in SPAK knock-in mice in which the kinase and thus NCC cannot be activated by WNK kinases. AngII or aldosterone was infused at 1440 or 700 µg/kg per day, respectively, for 14 days using osmotic minipumps. The aldosterone-treated mice were exposed to NaCl drinking water (1%) during the hormone administration. The arterial blood pressure was assessed using radiotelemetry. RESULTS: We observed that in the SPAK knock-in mice, the AngII-induced hypertensive effect was significantly reduced and associated with an absence of AngII-induced NCC phosphorylation. In contrast, the hypertensive effect of aldosterone was enhanced and was related with an increased response to amiloride, but not to thiazide-type diuretics, without a significant increase in NCC phosphorylation. CONCLUSION: Our data suggest that AngII-induced hypertension requires, at least partly, NCC activation via the WNK/SPAK signaling pathway, whereas aldosterone-induced hypertension depends on epithelial sodium channel activation in a WNK/SPAK-independent manner. SPAK knock-in mice emerge as a useful model to distinguish between the effects of AngII and aldosterone on distal nephrons.

Development of a bioactive glass-polymer composite for wound healing applications.

This study reports the production and characterization of a composite material for wound healing applications. A bioactive glass obtained by sol-gel process and doped with two different metal ions was investigated. Silver (Ag) and cobalt (Co) were chosen due to their antibacterial and angiogenic properties, respectively, very beneficial in the wound healing process. Poly(ε-caprolactone) (PCL) fibers were produced by electrospinning (ES) from a polymeric solution using acetone as a solvent. After optimization of the ES parameters, two main suspensions were prepared, namely: PCL containing bioactive glass nanoparticles (BG-NP) and PCL with Ag2O and CoO doped BG-NP (DP BG-NP), which were processed with different concentrations of BG-NP (0.25%, 0.5% and 0.75wt%). The composite membranes were characterized in terms of morphology, fiber diameter, weight loss, mineralization potential and mechanical performance.

Extended-release tramadol in the treatment of osteoarthritis: a multicenter, randomized, double-blind, placebo-controlled clinical trial.

OBJECTIVE: This study evaluated the efficacy and safety of tramadol extended-release (tramadol ER) tablets once daily in subjects with osteoarthritis pain. METHODS: This 12-week, multicenter, randomized, double-blind, placebo-controlled, parallel-group clinical trial included 1020 adults with osteoarthritis of the knee or hip and baseline pain intensity >or= 40 on a 100-mm pain visual analog scale (0 = no pain, 100 = extreme pain). Subjects took placebo or were titrated to a target dose of tramadol ER 100, 200, 300, or 400 mg once daily. MAIN OUTCOME MEASURES: The co-primary efficacy variables were pain and physical function subscales of the WOMAC Osteoarthritis Index and subject global assessment of disease activity. RESULTS: Mean changes in WOMAC Osteoarthritis Index pain and physical function subscales were significantly different between tramadol ER and placebo, overall (p

Are maximum bite forces of subjects 7 to 17 years of age related to malocclusion?

OBJECTIVE: To determine the effects of occlusion on maximum bite force of growing subjects. MATERIALS AND METHODS: Incisor and first molar bite force of children and adolescents was evaluated. Four cohorts were measured annually for 3 years, starting at approximately 7, 9, 12, and 15 years of age, respectively. The initial sample included 182 females and 198 males; there were 130 subjects with normal occlusion, 111 with Class I malocclusion, and 139 with Class II malocclusion. Multilevel analyses were performed to model the growth changes and compare groups. RESULTS: Maximum bite force increased significantly (P < .05) over time. Incisal forces peaked at 14.3 and 15.3 years of age for females and males, respectively. Maximum molar bite force peaked at 16 years for both males and females. Subjects with normal occlusion had significantly higher bite force than subjects with malocclusion. Maximum molar bite force exhibited a significant testing effect, with forces increasing 2.6 kg each year that the tests were repeated. CONCLUSIONS: Malocclusion has a detrimental effect on bite force. Changes in maximum bite force are also due to age, sex, and repeated testing.

Peroxisome proliferator-activated receptor-α stimulation by clofibrate favors an antioxidant and vasodilator environment in a stressed left ventricle.

BACKGROUND: Arterial high blood pressure is a risk factor for target organ damage; the most susceptible organs are the arteries, brain, kidneys, and heart. The damage mechanisms include oxidative stress and renin-angiotensin system (RAS) overactivity. Therefore, our aim was to study whether clofibrate-induced peroxisome proliferator-activated receptor-alpha (PPAR-α) stimulation is able to prevent alterations in cardiac functioning derived from RAS overstimulation in the left ventricle of rats with hypertension secondary to aortic coarctation and to improve antioxidant defenses. METHODS: Male Wistar rats were assigned to Control (Sham)- or aortic coarctation-surgery and further divided to receive (1 or 21 days) vehicle, clofibrate (100mg/kg), captopril (20mg/kg), or clofibrate+captopril. The left ventricle was obtained to measure: angiotensin II and -(1-7), AT1 and AT2 receptors, angiotensin converting enzyme (ACE)-1 and -2, and MAS receptor; the activity and expression of superoxide dismutase, catalase, endothelial nitric oxide synthase, the production of reactive oxygen species (ROS) and peroxidated lipids; as well as ex vivo cardiac functioning. RESULTS: Clofibrate decreased angiotensin II, AT1 receptor and ACE expression, and raised angiotensin-(1-7), AT2 receptor, ACE-2 expression, superoxide dismutase and endothelial nitric oxide synthase participation. These effects promoted lower coronary vascular resistance and improved mechanical work compared to aortic coarctated vehicle-treated rats. CONCLUSIONS: Clofibrate-induced PPAR-α stimulation changes the angiotensin II receptor profile, favors the ACE2/angiotensin-(1-7)/AT2 receptor axis decreasing the vasoconstrictor environment, activates the antioxidant defense, and facilitates endothelial nitric oxide synthase activity favoring vasodilation. This may represent a protection for the stressed heart.