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Hypercholesterolemia is one of the most important risk factors for cardiovascular diseases. However, it is mostly associated with vascular dysfunction and atherosclerotic lesions, while evidence of direct effects of hypercholesterolemia on cardiomyocytes and heart function is still incomplete and controversial. In this study, we assessed the direct effects of hypercholesterolemia on heart function and the electro-contractile properties of isolated cardiomyocytes. After 5 weeks, male Swiss mice fed with AIN-93 diet added with 1.25% cholesterol (CHO), developed an increase in total serum cholesterol levels and cardiomyocytes cholesterol content. These changes led to altered electrocardiographic records, with a shortening of the QT interval. Isolated cardiomyocytes displayed a shortening of the action potential duration with increased rate of depolarization, which was explained by increased IK, reduced ICa.L and altered INa voltage-dependent inactivation. Also, reduced diastolic [Ca2+]i was found with preserved adrenergic response and cellular contraction function. However, contraction of isolated hearts is impaired in isolated CHO hearts, before and after ischemia/reperfusion, although CHO heart was less susceptible to arrhythmic contractions. Overall, our results demonstrate that early hypercholesterolemia-driven increase in cellular cholesterol content is associated with direct modulation of the heart and cardiomyocytes' excitability, Ca2+ handling, and contraction.

Assuntos

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The aim of this study was to investigate the effect of acid challenge on the activation of matrix metalloproteinases (MMPs) in the Dentinoenamel junction of primary and permanent teeth submitted to radiotherapy. For this purpose, a total of 178 dental fragments obtained from molars were used, and randomly divided into 2 groups (primary and permanent teeth) / 4 experimental subgroups (irradiated and non-irradiated, demineralized and non-demineralized). The fragments were exposed to radiation, with a dose fraction of 2 Gy, for 5 consecutive days, until a total dose of 60 Gy was reached, with a total of 30 cycles, for 6 weeks. To determine the activity of MMPs on the dentinoenamel junction (DEJ), in situ zymography assays on 0.6mm dental fragments were performed. To assess whether MMP activity would be impacted by an acidic environment, the fragments were placed in a demineralizing solution (pH of 4.8). The finding was that irradiation activated MMPs in DEJ and these effects were more evident in permanent when compared with primary teeth. When the effect of an acid challenge on MMPs activity was investigated, demineralization was observed not to increase MMPs activity in non-irradiated teeth, but it did increase MMPs activity in irradiated teeth. In conclusion, an acid challenge was found to exacerbate activation of MMPs in DEJ of permanent teeth submitted to irradiation, but not in primary teeth.

Assuntos

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The elucidation of energetic patterns in adult viviparous elasmobranchs and their offspring can contribute to understanding ecophysiological questions, such as maternal-fetal metabolism and group life-history traits. We characterized the energetic substrates in pregnant individuals and stages of offspring development in the freshwater stingray Potamotrygon amandae. Our results show that the energetic distribution of the yolk is composed of more lipids than proteins, whereas the inverse pattern is observed in the egg and uterus, proving the plasticity of the energy provision of the species. As a novelty, we describe that yolk/intestine transfer occurs in this species.

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Molar-incisor hypomineralization (MIH) is a qualitative defect of dental enamel characterized by demarcated opacities present in permanent first molars and other teeth. It is considered a major clinical challenge in dentistry because it makes affected teeth more susceptible to fractures and dental caries. Its diagnosis is mainly clinical and there are few technological resources that allow for a more accurate diagnosis, especially with respect to the depth of the defect in the dental enamel. In this context, optical coherence tomography (OCT), which is routinely used in ophthalmology, can produce images of the depth of the dental enamel, making it a promising method. In this study, 33 teeth with different MIH severities were evaluated using OCT and microcomputed tomography (microCT). Semi-quantitative methods of grayscale pattern analysis were used to compare images obtained from different severities of MIH with the mineral density obtained through microCT. MicroCT evaluation revealed that hypomineralized enamel had a significantly lower mineral density than intact enamel. However, this difference was not observed between the mild and severe MIH lesions. In the OCT evaluation, significant differences were observed between the intact and hypomineralized enamel, and the gray value comparison provided a method for quantitative differentiation between the two. This study suggests that OCT could be a useful adjunct to traditional diagnostic methods for MIH, offering a noninvasive approach to evaluate enamel defects. RESEARCH HIGHLIGHTS: Combining optical coherence tomography with grayscale digital analysis shows potential as a promising method for diagnosing molar-incisor hypomineralization and assessing its level of severity.

Assuntos

RESUMO

Abstract The aim of this study was to investigate the effect of acid challenge on the activation of matrix metalloproteinases (MMPs) in the Dentinoenamel junction of primary and permanent teeth submitted to radiotherapy. For this purpose, a total of 178 dental fragments obtained from molars were used, and randomly divided into 2 groups (primary and permanent teeth) / 4 experimental subgroups (irradiated and non-irradiated, demineralized and non-demineralized). The fragments were exposed to radiation, with a dose fraction of 2 Gy, for 5 consecutive days, until a total dose of 60 Gy was reached, with a total of 30 cycles, for 6 weeks. To determine the activity of MMPs on the dentinoenamel junction (DEJ), in situ zymography assays on 0.6mm dental fragments were performed. To assess whether MMP activity would be impacted by an acidic environment, the fragments were placed in a demineralizing solution (pH of 4.8). The finding was that irradiation activated MMPs in DEJ and these effects were more evident in permanent when compared with primary teeth. When the effect of an acid challenge on MMPs activity was investigated, demineralization was observed not to increase MMPs activity in non-irradiated teeth, but it did increase MMPs activity in irradiated teeth. In conclusion, an acid challenge was found to exacerbate activation of MMPs in DEJ of permanent teeth submitted to irradiation, but not in primary teeth.

RESUMO

Purpose: To evaluate descriptively and quantitatively teeth affected by enamel hypomineralization (EH) using optical coherence microtomography (OCT). Methods: Twenty teeth were classified according to the European Academy of Pediatric Dentistry's molar incisor hypomineralization (MIH) index and separated into groups according to the degree of EH severity. For each tooth, scans were performed on both the affected and the non-affected areas, and their corresponding optical images were captured. Results: In the qualitative analyses, in most of the images bright lines were observed in relation to the enamel surface and a high level of photon scattering immediately below the enamel surface. This showed that the shading distribution can be identified as hypomineralized areas in which the scattering signal can be used as a diagnostic criterion. In the quantitative analyses, Tukey's test was performed to evaluate the means of the optical attenuation coefficient, which did not present significant differences. However, considering the correlation, homogeneity and contrast analyses, a statistically significant difference was observed between the groups. The group with severe MIH showed greater homogeneity and correlation, but less contrast. Conclusion: Currently, MIH has its severity measured by essentially clinical means. OCT processing techniques reveal advances in the diagnostic imaging of MIH, showing that image texture analysis can be a promising and useful method to aid in its diagnosis.

Assuntos

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We have previously shown that rice plants silenced for peroxisomal ascorbate peroxidase (OsAPX4-RNAi) display higher resilience to photosynthesis under oxidative stress and photorespiratory conditions. However, the redox mechanisms underlying that intriguing response remain unknown. Here, we tested the hypothesis that favorable effects triggered by peroxisomal APX deficiency on photosynthesis resilience under CAT inhibition are dependent on the intensity of photorespiration associated with the abundance of photosynthetic and redox proteins. Non-transformed (NT) and OsAPX4-RNAi silenced rice plants were grown under ambient (AC) or high CO2 (HC) conditions and subjected to 3-amino-1,2,4-triazole (3-AT)-mediated CAT activity inhibition. Photosynthetic measurements evidenced that OsAPX4-RNAi plants simultaneously exposed to CAT inhibition and HC lost the previously acquired advantage in photosynthesis resilience displayed under AC. Silenced plants exposed to environment photorespiration and CAT inhibition presented lower photorespiration as indicated by smaller Gly/Ser and Jo/Jc ratios and glycolate oxidase activity. Interestingly, when these silenced plants were exposed to HC and CAT-inhibition, they exhibited an inverse response compared to AC in terms of photorespiration indicators, associated with higher accumulation of proteins. Multivariate and correlation network analyses suggest that the proteomics changes induced by HC combined with CAT inhibition are substantially different between NT and OsAPX4-RNAi plants. Our results suggest that the intensity of photorespiration and peroxisomal APX-mediated redox signaling are tightly regulated under CAT inhibition induced oxidative stress, which can modulate the photosynthetic efficiency, possibly via a coordinated regulation of protein abundance and rearrangement, ultimately triggered by crosstalk involving H2O2 levels related to CAT and APX activities in peroxisomes.

Assuntos

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Trees in cacao Agroforestry systems (AFS) may present a high potential for cadmium (Cd) phytoextraction, helping to reduce Cd in cacao (Theobroma cacao L.) plants grown in contaminated soils. To assess this potential, four forest fine-woody species commonly found in cacao high-productive sites in Colombia (Tabebuia rosea, Terminalia superba, Albizia guachapele, and Cariniana pyriformis) were exposed to contrasting CdCl2 contamination levels (0, 6, and 12 ppm) on a hydroponic medium. Growth dynamics, tolerance index (TI), and Cd concentration and allocation in leaves, stems, and roots were evaluated for up to 90 days after initial exposure. T. superba, A. guachapele, and C. pyriformis were classified as moderately tolerant (TI > 0.6), and T. rosea was considered a sensitive species (TI < 0.35) under 12 ppm Cd contamination. Despite showing a high stem Cd concentration, C. pyriformis also showed the lowest relative growth rate. Among the evaluated forest species, A. guachapele exhibited the highest Cd accumulation capacity per plant (2.02 mg plant-1) but also exhibited a higher Cd allocation to leaves (4%) and a strong decrease in leaf and stem dry mass after 90 days of exposure (~75% and 50% respectively, compared to control treatments). Taking together all the favorable features exhibited by T. superba as compared to other CAFS tree species and recognized phytoextractor tree species in the literature, such as Cd hyperaccumulation, high tolerance index, low Cd concentration in leaves, and high Cd allocation to the stem (harvestable as wood), this species is considered to have a high potential for cadmium phytoextraction in cocoa agroforestry systems.

RESUMO

The accumulation of high cadmium (Cd) levels in cacao beans (Theobroma cacao) generate several commercial and health issues. We hypothesized that cacao phenotypic and genotypic diversity could provide new insights to decrease Cd accumulation in cacao beans. Nine cacao rootstock genotypes were evaluated for up to 90 days under 0, 6, and 12 (mg·kg-1) of CdCl2 exposure and Cd content and plant growth dynamics were measured in leaves, stems, and roots. Data revealed that all cacao genotypes studied here were highly tolerant to Cd, since they presented tolerance index ≥ 60%. In shoots, EET61 and PA46 presented the higher (~270 mg·kg DW-1) and lower (~20 mg·kg DW-1) Cd concentration, respectively. Accordingly, only the EET61 showed an increase in the shoot cadmium translocation factor over the 90 days of exposure. However, when analyzing cadmium allocation to different organs based on total plant dry mass production, none of the genotypes maintained high Cd compartmentalization into roots, since P46, which was the genotype with the highest allocation of Cd to the roots, presented only 20% of total cadmium per plant in this plant organ and 80% allocated into the shoots, under Cd 12 (mg·kg-1) and after 90 days of exposure. Thus, genotypic/phenotypic variability in cacao rootstocks may provide valuable strategies for maximizing the reduction in Cd content in shoots. In this sense, IMC67 and PA46 were the ones that stood out in the present study.

RESUMO

OBJECTIVE: To compare direct visual analysis (DVA) and intraoral scanning (IOS) for the assessment of developmental defects of the enamel (DDE). METHODS: Thirty-nine extracted permanent human teeth with DDE were selected by an experienced examiner and digitised using IOS. The scanning was recorded using the OBS Studio software parallel to the IOS software to obtain a coloured high-definition MP4 file of the process. Two other experienced, blinded, and calibrated examiners randomly analysed the same teeth through DVA and IOS. A third examiner resolved any disagreements between the two examiners. Descriptive statistics were used to analyse the frequencies of the scores. Cohen's kappa test was used to determine whether the DVA scores were different from those assigned using IOS. Spearman's test was used to verify non-random examiner errors. The Chi-square test was used to compare score frequencies. Statistical significance was set at p <0.05. RESULTS: Scores indicating more severe and extended DDE (p <0.05) were more frequently assigned with IOS than with DVA (IOS: 25.64%, 25.64%, 38.46%, and 35.90% between one-third to two-third of the lingual, occlusal, mesial, and distal surfaces, respectively; vs. DVA: 10.26%, 7.69%, 15.38%, and 10.26% for the respective aforementioned tooth surfaces). Contrarily, 'no visible enamel defect' was significantly less assigned for IOS than for DVA (IOS: 15.38%, 43.59%, 35.90%, 15.38%, and 17.95% for buccal, lingual, occlusal, mesial, and distal surfaces, respectively; vs. DVA: 38.46%, 66.67%, 56.41%, 51.28%, and 43.59% for the respective aforementioned tooth surfaces). Kappa agreement ranged from fair to moderate when comparing DVA and IOS; the correlation between both methods was positive, indicating that the examiners assigned the scores properly and the differences arose from employing different methods. CONCLUSION: The assessment of DDE differed depending on the method used. IOS scores indicated more severe and extended DDE than DVA scores. Clinical investigation is the next step in validating the use of IOS for DDE diagnosis. CLINICAL SIGNIFICANCE: This study showed that DDE can be assessed differently using IOS. It is clinically relevant as it directly affects the determination of the severity of the defect and dental treatment planning.

Assuntos