Abstract Objective Preservation of structural and biochemical properties of the root dentin matrix is crucial to favor healing and regenerative periodontal processes. Aim of this study was to ...evaluate the biochemical characteristics of collagen and chondroitin sulphate of root dentin surfaces exposed by periodontal disease after acid conditioning by means of an immunohistochemical technique. Design Human teeth scheduled for extraction due to periodontal reason were submitted to: (A) scaling and root planning; (B) ultrasonic instrumentation; (C) no instrumentation. Teeth were then exposed to: (1) 10% citric acid; (2) 17% EDTA; (3) no etching. A double immunolabeling technique was performed to identify type-I collagen and proteoglycans and analyzed under FEI-SEM. Results Use of 10% citric acid revealed intense labeling for collagen fibrils and proteoglycans; lower labeling was found after EDTA conditioning. Unetched specimens showed residual smear layer on the dentin surface resulting in no evident surface labeling. Conclusions This study supports the hypothesis that manual or ultrasonic instrumentation alone is not able to expose the sound dentin matrix, whereas a subsequent acidic conditioning exposes collagen fibrils and associated proteoglycans. The immunohistochemical technique revealed that despite their acidity, both citric acid and EDTA were able to preserve the structural and biochemical properties of the exposed dentin matrix.
Abstract Objectives The application of an electric field has been shown to positively influence the bonding of dentin bonding systems (DBS) by improving adhesive impregnation into dentin. However, ...the mechanism responsible for this phenomenon has not been completely elucidated. The aim of this study was to clarify the effects of pH, matrix ionic strength, and applied voltage on the migration of commonly used DBS monomers in a model matrix (agarose gel). Methods Some common monomers examined were bis-GMA (2,2-bis4-(2-hydroxy-3-methacryloyloxy propoxy) phenyl propane); HEMA (2-hydroxyethyl methacrylate); 2-MP (bis2-(methacryloyloxy) ethyl phosphate); TCDM di(hydroxyethyl methacrylate) ester of 5-(2,5,-dioxo tetrahydrofurfuryl)-3-methyl-3-cyclohexenyl-1,2-dicarboxylic acid; and TEGDMA (triethylene glycol dimethacrylate). Agarose gels poured into a horizontal 10-well electrophoretic cell were used to mimic the collagen fibrils of the dentin organic matrix. The role of pH, matrix ionic strength, and voltage on monomer migration was assayed by modifying the experimental conditions. Results Results of experiments performed at pH 3.1, 6.3, 8.5, and 12.3; at low, medium, and high ionic strength; and at 50 and 100 V clearly showed that DBA monomer migration toward both the anode and the cathode can be affected by each of these parameters. Significance Migration of acrylic monomers toward the anode or cathode can be achieved as desired by selective choice of pH, ionic strength, and applied voltage. Additional studies are needed to evaluate the synergistic effects of DBS monomer blends on migration in an electric field.
Background: We retrospectively evaluated the efficacy of first-line epirubicin and docetaxel in patients with metastatic, hormonal receptor (HR)-positive, and human epidermal growth factor ...receptor-2-negative breast cancer. A subgroup analysis evaluated the predictive value of immunohistochemistry-defined luminal subtype.
Methods: We included patients with at least one visceral and measurable site of metastatic disease. Patients were grouped as luminal A (HR
+
and Ki67<13%) or luminal B (HR
+
and Ki67>13%).
Results: Forty-four patients were entered and prognostic variables were similar between the subgroups. Luminal B patients achieved higher objective response rate than luminal A (69% versus 19%; P = 0·001), longer time to progression (12·2 months versus 8·6 months; P = 0·039), and longer overall survival (24·6 months versus 19·5 months; P = 0·041). The multivariate analysis confirmed the predictive value of luminal B subtype for longer time to progression.
Conclusions: Identification by Ki67 labelling index of human epidermal growth factor receptor-2-negative luminal A could predict a substantial benefit from systemic chemotherapy. Endocrine therapy would be the most appropriate therapy for luminal A tumours.
The aim of this study was to investigate whether an electrical device for dental adhesive application (ElectroBond) influences bonding of two-step etch-and-rinse adhesives.
Human teeth were selected ...and cut perpendicularly to their long axis to expose middle/ deep dentin. Specimens were then longitudinally sectioned into halves (experimental and control halves) to create two similar bonding substrates. Experimental halves were bonded using an ElectroBond-assisted application, while control halves were bonded with disposable sponges. The adhesives tested were Adper Scotchbond 1XT and XP-BOND. Bonded specimens were submitted to the microtensile bond strength test. Additional adhesive interfaces were prepared and processed for nanoleakage investigation involving TEM examination.
The microtensile bond test revealed higher values (p < 0.05) for both adhesives if ElectroBond was used during layering (55.5 +/- 7.9 MPa for Adper Scotchbond 1XT and 54.7 +/- 7.1 MPa for XP-BOND) compared to the conventional mechanical adhesive application technique (41.1 +/- 6.1 MPa for Adper Scotchbond 1XT and 38.0 +/- 7.8 MPa for XP-BOND). No difference between the two adhesives was found under the same application conditions. With electricity-assisted application, TEM micrographs revealed a significant decrease in nanoleakage expression compared to the controls.
The use of an electric current produced by ElectroBond during the application of two-step etch-and-rinse adhesives may enhance resin impregnation, thus improving dentin hybridization. Further studies should be done to confirm that this device can similarly improve adhesive application in vivo.
The natural enzymes involved in regulating many of the posttranslational modifications (PTMs) within the first 17 residues (Nt17) of Huntingtin exon1 (Httex1) remain unknown. A semisynthetic strategy ...that allows the site-specific introduction of PTMs within Nt17 by using expressed protein ligation (EPL) was developed. This strategy was used to produce untagged wild-type (wt) and T3-phosphorylated (pT3) Httex1 containing 23 glutamine residues (Httex1-23Q). Our studies show that pT3 significantly slows the oligomerization and fibrillization of Httex1-23Q and that Httex1 variants containing polyQ repeats below the pathogenic threshold readily aggregate and form fibrils invitro. These findings suggest that crossing the polyQ pathogenic threshold is not essential for Httex1 aggregation. The ability to produce wt or site-specifically modified tag-free Httex1 should facilitate determining its structure and the role of N-terminal PTMs in regulating the functions of Htt in health and disease.
The natural enzymes involved in regulating many of the posttranslational modifications (PTMs) within the first 17 residues (Nt17) of Huntingtin exon 1 (Httex1) remain unknown. A semisynthetic ...strategy that allows the site‐specific introduction of PTMs within Nt17 by using expressed protein ligation (EPL) was developed. This strategy was used to produce untagged wild‐type (wt) and T3‐phosphorylated (pT3) Httex1 containing 23 glutamine residues (Httex1‐23Q). Our studies show that pT3 significantly slows the oligomerization and fibrillization of Httex1‐23Q and that Httex1 variants containing polyQ repeats below the pathogenic threshold readily aggregate and form fibrils in vitro. These findings suggest that crossing the polyQ pathogenic threshold is not essential for Httex1 aggregation. The ability to produce wt or site‐specifically modified tag‐free Httex1 should facilitate determining its structure and the role of N‐terminal PTMs in regulating the functions of Htt in health and disease.
Maßgeschneidert: Ein Eintopfsemisynthesestrategie ermöglicht die ortsspezifische Einführung posttranslationaler Modifikationen in den N‐Terminus von Exon 1 des Huntingtin‐Proteins (Httex1). Auf diese Weise wurden unmarkiertes Wildtyp‐ und T3‐phosphoryliertes Httex1 erzeugt. Httex1 mit PolyQ‐Wiederholungseinheiten unterhalb der Pathogenitätsgrenze (Httex1‐23Q) aggregiert in vitro; dieser Prozess wird durch die Phosphorylierung an T3 verlangsamt.
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