Knowledge of the histochemical substrates of cellular and neurovascular connections in the gingiva is essential in order to understand the initial mechanisms of inflammation in the periodontium. ...Since the localization of the neuroendocrine peptide galanin in the gingiva is still unclear, we used immunohistochemical, in situ hybridization and immunoblot techniques to assess the localization of galanin in the gingiva of rat molars. Galanin‐immunoreactive nerve fibers were located around blood vessels in the lamina propria, beneath the epithelium, in the epithelial–proprial junction and in the basal layer of the epithelium. Galanin was highly expressed in the suprabasal keratinocytes of the gingival epithelium. The localization of galanin in gingival nerve fibers and the expression of galanin in keratinocytes of the gingival epithelium indicate that galanin may be a possible regulator of different cellular functions in the gingiva.
During tooth development, the inner and outer enamel epithelia fuse by mitotic activity to produce a bilayered epithelial sheath termed Hertwig's epithelial root sheath (HERS). The epithelial rests ...of Malassez (ERM) are the developmental residues of HERS and remain in the adult periodontal ligament (PDL). Although the cellular regulation of the Ca.sup.2+-binding proteins parvalbumin, calbindin-D28k, and calretinin has been reported in the inner and outer enamel epithelia during tooth development, an involvement of Ca.sup.2+-binding proteins in the ERM has not so far been characterized. Among the three Ca.sup.2+-binding proteins tested (calbindin D28k, parvalbumin, calretinin), we have only been able to detect calretinin in a subpopulation of adult rat molar ERM, by using quantitative immunohistochemical and confocal immunofluorescence techniques. TrkA (a marker for ERM) is present in numerous epithelial cell clusters, whereas calretinin has been localized in the cytosol and perinuclear region of a subpopulation of TrkA-positive cells. We conclude that, in inner and outer enamel epithelial cells, Ca.sup.2+ is regulated by calbindin, parvalbumin, and calretinin during tooth development, whereas in the ERM of adult PDL, Ca.sup.2+ is regulated only by calretinin. The expression of Ca.sup.2+-binding proteins is restricted in a developmental manner in the ERM. Keywords Epithelial rests of Malassez * Ca.sup.2+-binding proteins * Calretinin * Calbindin-D28k * Parvalbumin * Rat (Wistar)
Purpose
The aim of this study was to evaluate the role of host periosteum and recipient bed perforation on the healing of an onlay graft to the mandible based on histologic and immunohistochemical ...analysis.
Materials and methods
Each of the 12 adult sheep used in the study received four iliac corticocancellous onlay bone grafts on the lateral surface of the mandible. In experiment 1, the block graft was placed in direct contact with the recipient bed and fixed with micro-screws, and in experiment 2, the recipient cortical bed was perforated before graft placement. The host periosteum around the graft was excised before flap replacement in experiment 3, and in experiment 4, a sheet of silicone membrane was placed between the graft and the recipient bed. The animals were euthanised at 4, 8, 12 and 16 weeks after surgery and the findings were analysed by routine microscopy (haematoxylin and eosin and tartrate-resistant acid phosphatase TRAP stains) and immunohistochemistry for proliferation and apoptotic markers (Ki67, caspase-3 and TUNEL stains).
Results
After 8 weeks, full graft–host integration was seen in all the experimental groups except experiment 4. After 16 weeks, pronounced graft resorption and volume reduction was observed in experiments 1 and 2, whilst experiment 3 was characterised with extensive connective tissue infiltration and severe resorption of the graft. The number of osteoclasts expressed peaked at 4 weeks in experiments 1 and 2 and at 16 weeks in experiment 3. Immunoreactivity for Ki67 by osteoblasts lining the trabecular bone of the graft’s spongiosa expressed moderate level of Ki67 at 8 weeks, and thereafter declined markedly. The strongest expression of caspase-3 on the bone surface was observed after 16 weeks.
Discussion and conclusion
Recipient cortical bed perforation offered no advantage over non-perforated bed regarding healing and integration of a bone graft. Excision of the host overlying the periosteum was accompanied with rapid absorption of the grafts and partial or complete replacement with fibrous connective tissue. This study also demonstrated that cell death by apoptosis is a fundamental component of osteoblastic phenotypic differentiation during healing of corticocancellous bone graft.
The cell specific detection of enzyme activation in response to the physiological contractile load within muscle-tendon-bone unit is essential for understanding of the mechanical forces transmission ...from muscle cells via tendon to the bone. The hypothesis that the physiological mechanical loading regulates activation of Akt1/PKBalpha at Thr308 and at Ser473 in muscle fibers within muscle-tendon-bone unit was tested using quantitative immunohistochemistry, confocal double fluorescence analysis, and immunoblot analysis. In comparison to the staining intensities in peripheral regions of the muscle fibers, Akt1/PKBalpha was detected with a higher staining intensity in muscle fibers at the myotendinous junction (MTJ) areas. In muscle fibers at the MTJ areas, Akt1/PKBalpha is dually phosphorylated at Thr308 and Ser473. The immunohistochemical results were confirmed by immunoblot analysis. We conclude that contractile load generated by masticatory muscles induces local domain-dependent expression of Akt1/PKBalpha as well as activation by dually phosphorylation at Thr308 and Ser473 in muscle fibers at the MTJ areas within muscle-tendon-bone unit.
The cell specific detection of enzyme activation in response to the physiological contractile load within muscle-tendon-bone unit is essential for understanding of the mechanical forces transmission ...from muscle cells via tendon to the bone. The hypothesis that the physiological mechanical loading regulates activation of Akt1/PKBα at Thr308 and at Ser473 in muscle fibers within muscle-tendon-bone unit was tested using quantitative immunohistochemistry, confocal double fluorescence analysis, and immunoblot analysis. In comparison to the staining intensities in peripheral regions of the muscle fibers, Akt1/PKBα was detected with a higher staining intensity in muscle fibers at the myotendinous junction (MTJ) areas. In muscle fibers at the MTJ areas, Akt1/PKBα is dually phosphorylated at Thr308 and Ser473. The immunohistochemical results were confirmed by immunoblot analysis. We conclude that contractile load generated by masticatory muscles induces local domain-dependent expression of Akt1/PKBα as well as activation by dually phosphorylation at Thr308 and Ser473 in muscle fibers at the MTJ areas within muscle-tendon-bone unit.
Tenofovir alafenamide (TAF) is used as a hepatitis B virus (HBV) nucleotide reverse transcriptase inhibitor for the treatment of chronic HBV infection. However, the use of TAF suffers from its poor ...solubility and low bioavailability. Therefore, this study prepared and characterized chitosan nanoparticles (CHS NPs) loaded with TAF. Morphological findings demonstrated that CHS NPs are roughly spherical and homogeneous in shape. Besides, TAF‐loaded CHS NPs displayed the hydrodynamic diameter, zeta potential, and PDI of approximately 340 nm, 48.9 mV, and 0.65, respectively. The encapsulation efficiency is at about 50%, and TAF is released about 93% at the end of 80 hours at pH 7.4. In addition, human hepatocellular carcinoma cells (HepG2) are used for cell viability studies and it is observed that TAF‐loaded CHS NPs has 1.24 times less viable cells as compared to the control. Collectively, TAF‐loaded CHS NPs could be used as an efficient formulation for the treatment of chronic HBV infection.
The present study investigates the ability of chitosan nanoparticles (CHS NPs) as a biocompatible and biodegradable carrier for oral delivery of Tenofovir alafenamide (TAF). To the best of the authors' knowledge, this is the first report which focuses on the use of TAF‐loaded CHS NPs for controlled release.
Many engineering designs focus on the production of durable, ergonomic, and economical new materials. In today’s world where natural resources are rapidly decreasing, recycling waste materials is of ...great importance. As a result of the bending test, the sample’s return to its original dimensions shows the plastic feature of the material. It was observed that the tensile strength can be increased if the speed of the injection machine is well adjusted in the production of tensile strength testing samples. There was an increase in the screw tensile strength of the samples and the joint hardness strength. Thermogravimetric analysis (TGA) showed that the reference samples were completely crumbled around 480 °C, and it was observed that only quartz remained from the input materials. Differential scanning calorimetry (DSC) showed that the peak point in the reference sample was at the heat flow rate of 29 m/W, while it was 18 to 19 m/W in the doped groups. Melting temperature was observed in the range of 125 to 135 °C in all groups. The mechanical properties of the quartz-substituted samples increased compared to the reference sample. It was observed that the quartz and wood powder contained in the mixture worked in harmony.
The objective of this study is to assess the economic feasibility of installing high-efficiency solar panels in a yacht marina in the Çeşme district of Izmir, Türkiye. In this aim, the facility’s ...energy demand from the grid is reduced. The study compares ten different PV panel modules with various installation configurations, including fixed, horizontal, vertical, and two-axis. The most cost-effective option is determined with novel comparative economic indicators involving the costs associated with purchasing electricity from the grid. The PVGIS online tool is used to simulate energy production from solar panel systems and determine the ideal quantity of solar panels that can be deployed within the designated regions. New economic indicators, Relative Levelized Energy Cost (RLEC), and Relative Payback Period (RPBP) are proposed in the study to compare the economic performance of the different solar panel sets. The results indicate that the facility can compensate for 14.44% of its energy demand with the two-axis configuration. Module 5 yielded the best relative economic performance with an RLEC of 0.090 $/kWh. The best Payback Period (PBP) is obtained from fixed module 7, while the best RPBP is achieved with fixed module 5 at 7.113 years, which shows the importance of using comparative economic indicators for suitable energy systems.
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