Age and 17β-Estradiol (E2) Facilitate Nuclear Export and Argonaute Loading of microRNAs in the Female Brain

Aging in women is accompanied by a dramatic change in circulating sex steroid hormones. Specifically, the primary circulating estrogen, 17β-estradiol (E2), is nearly undetectable in post-menopausal women. This decline is associated with a variety of cognitive and mood disorders, yet hormone replacement therapy is only effective within a narrow window of time surrounding the menopausal transition. Our previous work identified microRNAs as a potential molecular substrate underlying the change in E2 efficacy associated with menopause in advanced age. Specifically, we showed that E2 regulated a small subset of mature miRNAs in the aging female brain. In this study, we hypothesized that E2 regulates the stability of mature miRNAs by altering their subcellular localization and their association with argonaute proteins. We also tested the hypothesis that the RNA binding protein, hnRNP A1, was an important regulator of mature miR-9-5p expression in neuronal cells. Our results demonstrated that E2 treatment affected miRNA subcellular localization and its association with argonaute proteins differently, depending on the length of time following E2 deprivation (i.e., ovariectomy). We also provide strong evidence that hnRNP A1 regulates the transcription of pri-miR-9 and likely plays a posttranscriptional role in mature miR-9-5p turnover. Taken together, these data have important implications for considering the optimal timing for hormone replacement therapy, which might be less dependent on age and more related to how long treatment is delayed following menopause.

Absolute Quantification of Phosphorylated ERβ Amino Acids in the Hippocampus of Women and in A Rat Model of Menopause

The rapid decline of circulating 17β-estradiol (E2) at menopause leads to negative neurological consequences, although hormone therapy paradoxically has both harmful and positive effects depending on the age at which it is delivered. The inconsistent response to E2 suggests unappreciated regulatory mechanisms for estrogen receptors (ERs), and we predicted it could be due to age-related differences in ERβ phosphorylation. We assessed ERβ phosphorylation using a sensitive mass spectrometry approach that provides absolute quantification (AQUA-MS) of individually phosphorylated residues. Specifically, we quantified phosphorylated ERβ in the hippocampus of women (aged 21-83 years) and in a rat model of menopause at 4 residues with conserved sequence homology between the 2 species: S105, S176, S200, and Y488. Phosphorylation at these sites, which spanned all domains of ERβ, were remarkably consistent between the 2 species, showing high levels of S105 phosphorylation (80%-100%) and low levels of S200 (20%-40%). Further, S200 phosphorylation decreased with aging in humans and loss of E2 in rats. Surprisingly, Y488 phosphorylation, which has been linked to ERβ ligand-independent actions, exhibited approximately 70% phosphorylation, unaltered by species, age, or E2, suggesting ERβ's primary mode of action may not require E2 binding. We further show phosphorylation at 2 sites directly altered ERβ DNA-binding efficiency, and thus could affect its transcription factor activity. These findings provide the first absolute quantification of ERβ phosphorylation in the human and rat brain, novel insights into ERβ regulation, and a critical foundation for providing more targeted therapeutic options for menopause in the future.

17β-Estradiol Regulates miR-9-5p and miR-9-3p Stability and Function in the Aged Female Rat Brain

Clinical studies demonstrated that the ovarian hormone 17β-estradiol (E2) is neuroprotective within a narrow window of time following menopause, suggesting that there is a biological switch in E2 action that is temporally dependent. However, the molecular mechanisms mediating this temporal switch have not been determined. Our previous studies focused on microRNAs (miRNA) as one potential molecular mediator and showed that E2 differentially regulated a subset of mature miRNAs which was dependent on age and the length of time following E2 deprivation. Notably, E2 significantly increased both strands of the miR-9 duplex (miR-9-5p and miR-9-3p) in the hypothalamus, raising the possibility that E2 could regulate miRNA stability/degradation. We tested this hypothesis using a biochemical approach to measure miRNA decay in a hypothalamic neuronal cell line and in hypothalamic brain tissue from a rat model of surgical menopause. Notably, we found that E2 treatment stabilized both miRNAs in neuronal cells and in the rat hypothalamus. We also used polysome profiling as a proxy for miR-9-5p and miR-9-3p function and found that E2 was able to shift polysome loading of the miRNAs, which repressed the translation of a predicted miR-9-3p target. Moreover, miR-9-5p and miR-9-3p transcripts appeared to occupy different fractions of the polysome profile, indicating differential subcellular. localization. Together, these studies reveal a novel role for E2 in modulating mature miRNA behavior, independent of its effects at regulating the primary and/or precursor form of miRNAs.

Reentry of endodontic access cavities: composite residue and loss of tooth substance

The purpose of this study was to investigate the ability of dentists to remove composite fillings from endodontic access cavities using illumination from a conventional light source (CLS) versus the fluorescence-aided identification technique (FIT) in terms of completeness, selectivity and treatment duration. Therefore, two independent operators removed composite resin from six sets of root-filled incisors in a maxillary model under simulated clinical conditions using the CLS or FIT method (twelve teeth per operator and technique). The duration of treatment was recorded and before-after micro-CT scans were superimposed for volumetric assessment of treatment completeness and selectivity. Statistical significance was determined by t-testing and two-way ANOVA for operator comparison. Overall, there was no significant difference between FIT and CLS in terms of volume, height and area of composite residues (p=0.98 / p=0.75 / p=0.64) and regarding hard tissue loss in terms of volume, depth and area (p= 0.93 / p= 0.70 / p= 0.14). However, there was a significant difference between the two groups regarding treatment time (FIT= 428s, CLS=523s; p=0.023). Significant differences between operators regardless of method were found for volume, height and area of composite residues (p<0.05) and also for defect area (p=0.01) and time (p<0.001). Significant differences between operators including the method was only found for height of composites (p=0.037). It can be concluded, that composite remnants and tooth structure losses may occur after reentry of root-filled teeth regardless of the illumination method (conventional vs. fluorescence-aided) and operator, but preparation was less time-consuming with FIT.

Quantitative evaluation of the progressive wear of powered interproximal reduction systems after repeated use : An in vitro study

PURPOSE

To evaluate the residual surface roughness of 5 common diamond-coated interproximal reduction (IPR) systems after consecutive in vitro applications in relation to system, diamond grain size, and instrument thickness.

METHODS

IPR was performed on 80 extracted human incisors using motor-driven strips and discs under predefined conditions. The IPR auxiliaries were applied at 5 consecutive sessions of 20 s on intact interproximal surfaces, and the surface profile (R_a, R_z, R_max) was analyzed at baseline and after each session with an optical profilometer.

RESULTS

No overall significant difference in the roughness values was found between systems (P = 0.07 for R_a, P = 0.33 for R_z, and P = 0.48 for R_max). There was a significant average decrease of R_a, R_z, and R_max for all systems for every unit increase in time by -0.171 μm (P < 0.001), -3.297 (P ≤ 0.001), and -2.788 μm (P = 0.001), respectively. R_a, R_z, and R_max values increased significantly, i.e., by 0.194 μm (P = 0.003), 5.890 μm (P = 0.001), and 5.319 μm (P = 0.010) as instrument thickness increased by one unit. No significant reductions in R_a, R_z, and R_max were observed across grain sizes (-0.008 μm [P > 0.05], -0.244 μm [P > 0.05], and -0.179 μm [P > 0.05], respectively). There was no evidence of interaction between system and time as the P values for R_a, R_z, and R_max were 0.88, 0.51, and 0.70, respectively.

CONCLUSIONS

All IPR materials presented significant gradual decrease of surface roughness after repeated applications. There were no significant roughness changes among auxiliaries of different grain sizes. Thinner auxiliaries showed significantly more roughness reduction, possibly requiring more frequent replacement than thick auxiliaries in clinical practice.

Increased flexibility in the use of exogenous lipoic acid by Staphylococcus aureus

Lipoic acid is a cofactor required for intermediary metabolism that is either synthesized de novo or acquired from environmental sources. The bacterial pathogen Staphylococcus aureus encodes enzymes required for de novo biosynthesis, but also encodes two ligases, LplA1 and LplA2, that are sufficient for lipoic acid salvage during infection. S. aureus also encodes two H proteins, GcvH of the glycine cleavage system and the homologous GcvH-L encoded in an operon with LplA2. GcvH is a recognized conduit for lipoyl transfer to α-ketoacid dehydrogenase E2 subunits, while the function of GcvH-L remains unclear. The potential to produce two ligases and two H proteins is an unusual characteristic of S. aureus that is unlike most other Gram positive Firmicutes and might allude to an expanded pathway of lipoic acid acquisition in this microorganism. Here, we demonstrate that LplA1 and LplA2 facilitate lipoic acid salvage by differentially targeting lipoyl domain-containing proteins; LplA1 targets H proteins and LplA2 targets α-ketoacid dehydrogenase E2 subunits. Furthermore, GcvH and GcvH-L both facilitate lipoyl relay to E2 subunits. Altogether, these studies identify an expanded mode of lipoic acid salvage used by S. aureus and more broadly underscore the importance of bacterial adaptations when faced with nutritional limitation.

Cutaneous Lesions of the External Genitalia

Individuals with cutaneous diseases of the external genitalia often initially present to their primary care provider. When present, these conditions may be associated with considerable physical symptoms and psychological distress. Dermatoses affecting the genitals may be of infectious, inflammatory, or neoplastic cause, and can be processes confined to the genitalia or a manifestation of a more widespread dermatologic condition. This article provides a guide to recognizing and managing common genital dermatoses and when to refer for specialist opinion.

Marginal Gap Formation in Approximal “Bulk Fill” Resin Composite Restorations After Artificial Ageing

The aim of this in vitro study was to investigate the marginal gap formation of a packable “regular” resin composite (Filtek Supreme XTE [3M ESPE]) and two flowable “bulk fill” resin composites (Filtek Bulk Fill [3M ESPE] and SDR [DENTSPLY DeTrey]) along the approximal margins of Class II restorations. In each of 39 extracted human molars (n=13 per resin composite), mesial and distal Class II cavities were prepared, placing the gingival margins below the cemento-enamel junction. The cavities were restored with the adhesive system OptiBond FL (Kerr) and one of the three resin composites. After restoration, each molar was cut in half in the oro-vestibular direction between the two restorations, resulting in two specimens per molar. Polyvinylsiloxane impressions were taken and “baseline” replicas were produced. The specimens were then divided into two groups: At the beginning of each month over the course of six months' tap water storage (37°C), one specimen per molar was subjected to mechanical toothbrushing, whereas the other was subjected to thermocycling. After artificial ageing, “final” replicas were produced. Baseline and final replicas were examined under the scanning electron microscope (SEM), and the SEM micrographs were used to determine the percentage of marginal gap formation in enamel or dentin. Paramarginal gaps were registered. The percentages of marginal gap formation were statistically analyzed with a nonparametric analysis of variance followed by Wilcoxon-Mann-Whitney tests and Wilcoxon signed rank tests, and all p-values were corrected with the Bonferroni-Holm adjustment for multiple testing (significance level: α=0.05). Paramarginal gaps were analyzed descriptively. In enamel, significantly lower marginal gap formation was found for Filtek Supreme XTE compared to Filtek Bulk Fill (p=0.0052) and SDR (p=0.0289), with no significant difference between Filtek Bulk Fill and SDR (p=0.4072). In dentin, significantly lower marginal gap formation was found for SDR compared to Filtek Supreme XTE (p&lt;0.0001) and Filtek Bulk Fill (p=0.0015), with no significant difference between Filtek Supreme XTE and Filtek Bulk Fill (p=0.4919). Marginal gap formation in dentin was significantly lower than in enamel (p&lt;0.0001). The percentage of restorations with paramarginal gaps varied between 0% and 85%, and for all three resin composites the percentages were markedly higher after artificial ageing. The results from this study suggest that in terms of marginal gap formation in enamel, packable resin composites may be superior to flowable “bulk fill” resin composites, while in dentin some flowable “bulk fill” resin composites may be superior to packable ones.

Invasive floating macrophytes reduce greenhouse gas emissions from a small tropical lake

Floating macrophytes, including water hyacinth (Eichhornia crassipes), are dominant invasive organisms in tropical aquatic systems, and they may play an important role in modifying the gas exchange between water and the atmosphere. However, these systems are underrepresented in global datasets of greenhouse gas (GHG) emissions. This study investigated the carbon (C) turnover and GHG emissions from a small (0.6 km²) water-harvesting lake in South India and analysed the effect of floating macrophytes on these emissions. We measured carbon dioxide (CO₂) and methane (CH₄) emissions with gas chambers in the field as well as water C mineralization rates and physicochemical variables in both the open water and in water within stands of water hyacinths. The CO₂ and CH₄ emissions from areas covered by water hyacinths were reduced by 57% compared with that of open water. However, the C mineralization rates were not significantly different in the water between the two areas. We conclude that the increased invasion of water hyacinths and other floating macrophytes has the potential to change GHG emissions, a process that might be relevant in regional C budgets.

Enamel Surface Changes After Exposure to Bleaching Gels Containing Carbamide Peroxide or Hydrogen Peroxide

OBJECTIVE

This study evaluated the differences in enamel color change, surface hardness, elastic modulus, and surface roughness between treatments with four bleaching gels containing carbamide peroxide (two at 10% and one each at 35%, and 45%) and two bleaching gels containing hydrogen peroxide (two at 40%).

METHODS

Enamel specimens were bleached and color changes were measured. Color change was calculated using either ΔE or the Bleaching Index (BI). Then, surface hardness, elastic modulus, and surface roughness of the enamel specimens were evaluated. All measurements were performed at baseline and directly after the first bleaching treatment for all carbamide peroxide- and hydrogen peroxide-containing bleaching gels. In addition, final measurements were made 24 hours after each of a total of 10 bleaching treatments for carbamide peroxide bleaching gels, and 1 week after each of a total of three bleaching treatments for hydrogen peroxide bleaching gels.

RESULTS

After the last bleaching treatment, respective ΔE scores were 17.6 and 8.2 for the two 10% carbamide peroxide gels, 12.9 and 5.6 for the 45% and 35% carbamide peroxide gels, and 9.6 and 13.9 for the two 40% hydrogen peroxide gels. The respective BI scores were -2.0 and -2.0 for the two 10% carbamide peroxide gels, -3.5 and -1.5 for the 45% and 35% carbamide peroxide gels, and -2.0 and -3.0 for the two 40% hydrogen peroxide gels. Each bleaching gel treatment resulted in significant whitening; however, no significant difference was found among the gels after the last bleaching. Whitening occurred within the first bleaching treatments and did not increase significantly during the remaining treatments. Surface hardness significantly decreased after the last bleaching treatment, when 10% carbamide peroxide was used. Furthermore, significant changes in the elastic modulus or surface roughness occurred only after treatment with 10% carbamide peroxide.

CONCLUSION

All six bleaching gels effectively bleached the enamel specimens independent of their concentration of peroxide. Gels with low peroxide concentration and longer contact time negatively affected the enamel surface.

Retention of Root Canal Posts: Effect of Cement Film Thickness, Luting Cement, and Post Pretreatment

The aim of this study was to investigate the effect of the cement film thickness of a zinc phosphate or a resin cement on retention of untreated and pretreated root canal posts. Prefabricated zirconia posts (CosmoPost: 1.4 mm) and two types of luting cements (a zinc phosphate cement [DeTrey Zinc] and a self-etch adhesive resin cement [Panavia F2.0]) were used. After removal of the crowns of 360 extracted premolars, canines, or incisors, the root canals were prepared with a parallel-sided drill system to three different final diameters. Half the posts did not receive any pretreatment. The other half received tribochemical silicate coating according to the manufacturer's instructions. Posts were then luted in the prepared root canals (n=30 per group). Following water storage at 37°C for seven days, retention of the posts was determined by the pull-out method. Irrespective of the luting cement, pretreatment with tribochemical silicate coating significantly increased retention of the posts. Increased cement film thickness resulted in decreased retention of untreated posts and of pretreated posts luted with zinc phosphate cement. Increased cement film thickness had no influence on retention of pretreated posts luted with resin cement. Thus, retention of the posts was influenced by the type of luting cement, by the cement film thickness, and by the post pretreatment.

Influence of Surface Roughness on Mechanical Properties of Two Computer-aided Design/Computer-aided Manufacturing (CAD/CAM) Ceramic Materials

The aim of this study was to evaluate the influence of surface roughness on surface hardness (Vickers; VHN), elastic modulus (EM), and flexural strength (FLS) of two computer-aided design/computer-aided manufacturing (CAD/CAM) ceramic materials. One hundred sixty-two samples of VITABLOCS Mark II (VMII) and 162 samples of IPS Empress CAD (IPS) were ground according to six standardized protocols producing decreasing surface roughnesses (n=27/group): grinding with 1) silicon carbide (SiC) paper #80, 2) SiC paper #120, 3) SiC paper #220, 4) SiC paper #320, 5) SiC paper #500, and 6) SiC paper #1000. Surface roughness (Ra/Rz) was measured with a surface roughness meter, VHN and EM with a hardness indentation device, and FLS with a three-point bending test. To test for a correlation between surface roughness (Ra/Rz) and VHN, EM, or FLS, Spearman rank correlation coefficients were calculated. The decrease in surface roughness led to an increase in VHN from (VMII/IPS; medians) 263.7/256.5 VHN to 646.8/601.5 VHN, an increase in EM from 45.4/41.0 GPa to 66.8/58.4 GPa, and an increase in FLS from 49.5/44.3 MPa to 73.0/97.2 MPa. For both ceramic materials, Spearman rank correlation coefficients showed a strong negative correlation between surface roughness (Ra/Rz) and VHN or EM and a moderate negative correlation between Ra/Rz and FLS. In conclusion, a decrease in surface roughness generally improved the mechanical properties of the CAD/CAM ceramic materials tested. However, FLS was less influenced by surface roughness than expected.

Bonding of restorative materials to dentin with various luting agents

The aim was to compare eight types of luting agents when used to bond six indirect, laboratory restorative materials to dentin. Cylinders of the six restorative materials (Esteticor Avenir [gold alloy], Tritan [titanium], NobelRondo [feldspathic porcelain], Finesse All-Ceramic [leucite-glass ceramic], Lava [zirconia], and Sinfony [resin composite]) were ground and air-abraded. Cylinders of feldspathic porcelain and glass ceramic were additionally etched with hydrofluoric acid and were silane-treated. The cylinders were luted to ground human dentin with eight luting agents (DeTrey Zinc [zinc phosphate cement], Fuji I [conventional glass ionomer cement], Fuji Plus [resin-modified glass ionomer cement], Variolink II [conventional etch-and-rinse resin cement], Panavia F2.0 and Multilink [self-etch resin cements], and RelyX Unicem Aplicap and Maxcem [self-adhesive resin cements]). After water storage at 37°C for one week, the shear bond strength of the specimens (n=8/group) was measured, and the fracture mode was stereomicroscopically examined. Bond strength data were analyzed with two-factorial analysis of variance (ANOVA) followed by Newman-Keuls' Multiple Range Test (α=0.05). Both the restorative material and the luting agent had a significant effect on bond strength, and significant interaction was noted between the two variables. Zinc phosphate cement and glass ionomer cements produced the lowest bond strengths, whereas the highest bond strengths were found with the two self-etch and one of the self-adhesive resin cements. Generally, the fracture mode varied markedly with the restorative material. The luting agents had a bigger influence on bond strength between restorative materials and dentin than was seen with the restorative material.

Operator Variability Using Different Polishing Methods and Surface Geometry of a Nanohybrid Composite

The integration of a one-step polisher into a multi-step finishing procedure saves time and leads to a reproducible polishing result for different operators.

Performance of Different Polishing Techniques for Direct CAD/CAM Ceramic Restorations

VITA Mark II and IPS Empress CAD specimens polished with Sof-Lex discs exhibit smoother surfaces than glazed specimens. The investigated ceramic polishing systems are universally applicable and show increased durability, but they do not result in smoother surfaces than Sof-Lex treatment. Furthermore, certain steps of some polishing methods do not contribute to improved smoothness and could be omitted.

A screening test of auditory comprehension for individuals with severe physical disability (PACST)

Tests of auditory comprehension are frequently unsuitable for patients with physically disabling conditions as they require abilities such as good vision or physical manipulation of test materials. A suitable test is required to assess patients who can only indicate 'yes' or 'no'. This has implications for enabling patients to make decisions about their care. A test consisting of 60 Yes-No questions was developed from a larger set tested on normals. A clinical trial was completed and the test found to be a useful tool. It allocates patients to three groups: normal, impaired and chance performance.

Assessing auditory comprehension in the context of severe physical disability: the PACST

Existing tests of auditory comprehension are frequently unsuitable for patients with physically disabling conditions as tests require skills such as physical manipulation of materials. A suitable test is required to assess the reliability and validity of responses in patients who can only indicate 'yes' and 'no'. This has implications for enabling patients to participate, for example, in decision making over their care. In the construction of the Putney Auditory Comprehension Screening Test (PACST) 200 normal participants were tested with 258 yes/no questions. From their results a test consisting of 60 unambiguous questions, varying in difficulty, type, syntactic complexity and length were selected. A clinical trial was completed with 112 patients from the Royal Hospital for Neuro-disability. The 60 item test was found to be reliable and valid. Results were also compared with independent ratings by ward managers and speech and language therapists. Effects of demographic variables were as expected. A 60 question test was developed which was shown by the clinical trial to be a useful tool. Questions vary in difficulty, but not enough to establish a difficulty gradient. On the basis of performance on the test, patients can be allocated to three groups: normal, impaired, and chance performance.

Inhibition and reversal of endotoxin-, aggregated IgG- and paf-induced hypotension in the rat by SRI 63-072, a paf receptor antagonist

Platelet activating factor (paf) given intravenously produces systemic hypotension in the rat. Similar effects can be induced using endotoxin or heat-aggregated IgG challenges, which are thought to involve endogenous paf release. Extending this concept, we have examined the ability of the paf antagonist SRI 63-072 to inhibit or reverse systemic hypotension induced with paf, heat-aggregated IgG or endotoxin 0111-B4 in rats. At 100 ng kg-1 paf, there occurred a 38.6 +/- 5.1% decrease in carotid mean arterial pressure (MAP) followed by a 3.2 +/- 0.7 min recovery period (RP) to return to normal pressure values. The ED50 of SRI 63-072 was 0.16 mg kg-1 i.v. (MAP) and 0.25 mg kg-1 (RP) when given 1-5 min before the paf challenge. Endotoxin (15 mg kg-1 i.v.) produced a hypotensive response (54 +/- 8% decrease in MAP) and a corresponding 80% decrease in mesenteric artery blood flow. When given 2-8 min after endotoxin, 1.0 mg kg-1 i.v. SRI 63-072 totally restored blood pressure and artery blood flow. SRI 63-072 similarly reversed heat-aggregated IgG (10 mg kg-1) induced reduction of MAP, with an ED50 of 0.05 mg kg-1 i.v. The observations that SRI 63-072 can inhibit or reverse systemic vascular effects produced from paf and other provocators of endogenous paf release strongly implicates paf as a common final mediator of hypotension and shock. As SRI 63-072 is a competitive receptor antagonist, the hypotensive effects of these provocators appear to be mediated by vascular receptors for paf.