[Regulation mechanism of resveratrol on odontogenic differentiation of human dental pulp stem cells].

PURPOSE: To investigate whether resveratrol promotes odontogenic differentiation of human dental pulp stem cells(DPSCs) by up-regulating the expression of silent information regulator 1 (SIRT1) and activating ß-catenin signaling pathway. METHODS: Different concentrations of resveratrol(0, 10, 15, 20 and 50 µmol/L) were used to treat DPSCs for 7 days and 14 days, and cell proliferative activity was detected by CCK-8. After odontogenic differentiation induced by 15 µmol/L resveratrol for 7 days, alkaline phosphatase(ALP) staining was performed and real-time quantitative reverse transcription PCR(qRT-PCR) was used to detect the mRNA expression of Runt-related transcription factor 2 (Runx2), dentin sialophosphoprotein(DSPP) and dentin matrix protein-1(DMP-1) in DPSCs. Western blot was used to detect the expression of SIRT1 in DPSCs on a specific day (0, 3rd, 5th, 7th and 14th) after differentiation induction. Western blot was also used to detect the expression of SIRT1 and activated ß-catenin during odontogenic differentiation of DPSCs treated by 15 µmol/L resveratrol for 7 days. The experimental data was analyzed with GraphPad Prism 9 software package. RESULTS: 15 µmol/L resveratrol had no significant effect on proliferation of DPSCs on the 7th and 14th day; 15 µmol/L resveratrol promoted odontogenic differentiation of DPSCs and up-regulated mRNA expression of RUNX2, DSPP, and DMP-1 in DPSCs; the expression of SIRT1 was the highest on the 7th day during odontogenic differentiation induction. Resveratrol resulted in the increasing protein expressions of SIRT1 and activated ß-catenin when DPSCs was induced to odontogenic differentiation for 7 days. CONCLUSIONS: Resveratrol promotes odontogenic differentiation of human DPSCs by up-regulating the expression of SIRT1 protein and activating ß-catenin signaling pathway.

Effect of oxidation at an elevated temperature on the evolution of phases, microstructure, and properties of the oxide films formed on the surface of TiZr.

This study examined the evolution of the microstructure, microhardness, corrosion resistance, and selective leaching properties of oxide films formed on the surface of a Ti-50Zr (%) alloy during heat treatment at 600 °C for various time intervals. According to our experimental results, the growth and evolution of oxide films can be divided into three stages. In stage I (heat treatment for less than 2 min), ZrO2 was first formed on the surface of the TiZr alloy, which slightly improved its corrosion resistance. In stage II (heat treatment for 2-10 min), the initially generated ZrO2 is gradually transformed into ZrTiO4 from the top to the bottom of the surface layer. The formation of ZrTiO4 significantly improves the microhardness and corrosion resistance of the alloy. In stage III (heat treatment for more than 10 min), microcracks appeared and propagated on the surface of the ZrTiO4 film, deteriorating the surface properties of the alloy. The ZrTiO4 began to peel off after heat treatment for more than 60 min. The untreated and heat-treated TiZr alloys exhibited excellent selective leaching properties in Ringer's solution, whereas a trace amount of suspended ZrTiO4 oxide particles formed in the solution after soaking the 60 min heat-treated TiZr alloy for 120 days. Surface modification of the TiZr alloy by generating an intact ZrTiO4 oxide film effectively improved its microhardness and corrosion resistance; however, oxidation should be performed appropriately to obtain materials with optimal properties for biomedical applications.

Effectiveness of platelet rich plasma in burn wound healing: a systematic review and meta-analysis.

BACKGROUND: To evaluate the efficacy of platelet-rich plasma (PRP) in the treatment of burn wounds. METHODS: A comprehensive literature survey was conducted in electronic medical journal databases to identify studies that examined the effect of PRP treatment to burn wounds and meta-analyses of mean differences (MD) standardized MD, or odds ratios were performed. RESULTS: The percentage of graft take was not significantly different between PRP-treated and control wound areas. Healing rate was significantly better in PRP-treated wounds. Healing time was also significantly less in PRP-treated wounds. There was no significant difference between PRP-treated and control wound areas in epithelialization or in the incidence of adverse events. Incidence of infection was also not different between PRP-treated and control wound areas. Scar assessment score was significantly better in PRP-treated than in control wound areas. CONCLUSION: PRP treatment to burn wounds is found to improve healing. Variations in study design and sample size, types of wounds, PRP preparation protocols, and high risk of bias in some of the included studies may have impact on these outcomes.

microRNA-26a Directly Targeting MMP14 and MMP16 Inhibits the Cancer Cell Proliferation, Migration and Invasion in Cutaneous Squamous Cell Carcinoma.

PURPOSE: To investigate the specific effect and underlying mechanism of microRNA-26a-5p (miR-26a) in cutaneous squamous cell carcinoma (CSCC). METHODS: miR-26a and MMP14/16 mRNA expression were detected by qRT-PCR analysis. Functional experiments were used to detect the role of miR-26a on CSCC progression. Western blot was used for protein detection. Luciferase assay was used to detect miR-26a directly targeting MMP14 and MMP16. Xenograft nude mice model was used to determine the effect of miR-26a on tumorigenesis. RESULTS: miR-26a was decreased in CSCC tissues and cells. Forced miR-26a suppressed the progression of SCL-1 and A431 cells. Furthermore, miR-26a directly targeted MMP14 and MMP16 to inhibit their expression. Forced expression of MMP14 and MMP16 removed the miR-26a's inhibitory effect on CSCC development. The in vivo tumor growth assay showed that miR-26a suppressed CSCC tumorigenesis by targeting MMP14 and MMP16. CONCLUSION: Our study suggested miR-26a inhibits cancer cell proliferation, migration and invasion in CSCC by targeting MMP14 and MMP16.

The Emerging Role of Nutritional Vitamin D in Secondary Hyperparathyroidism in CKD.

In chronic kidney disease (CKD), hyperphosphatemia induces fibroblast growth factor-23 (FGF-23) expression that disturbs renal 1,25-dihydroxy vitamin D (1,25D) synthesis; thereby increasing parathyroid hormone (PTH) production. FGF-23 acts on the parathyroid gland (PTG) to increase 1α-hydroxylase activity and results in increase intra-gland 1,25D production that attenuates PTH secretion efficiently if sufficient 25D are available. Interesting, calcimimetics can further increase PTG 1α-hydroxylase activity that emphasizes the demand for nutritional vitamin D (NVD) under high PTH status. In addition, the changes in hydroxylase enzyme activity highlight the greater parathyroid 25-hydroxyvitmain D (25D) requirement in secondary hyperparathyroidism (SHPT); the higher proportion of oxyphil cells as hyperplastic parathyroid progression; lower cytosolic vitamin D binding protein (DBP) content in the oxyphil cell; and calcitriol promote vitamin D degradation are all possible reasons supports nutritional vitamin D (NVD; e.g., Cholecalciferol) supplement is crucial in SHPT. Clinically, NVD can effectively restore serum 25D concentration and prevent the further increase in PTH level. Therefore, NVD might have the benefit of alleviating the development of SHPT in early CKD and further lowering PTH in moderate to severe SHPT in dialysis patients.

Pyruvate in reduced osmolarity oral rehydration salt corrected lactic acidosis in sever scald rats.

BACKGROUND: A novel pyruvate-based oral rehydration salt (Pyr-ORS) was demonstrated of superiority over bicarbonate- or citrate-based one to preserve organ function and correct lactic acidosis in rehydration of lethal shock in animals. This study further compared these effects between low-osmolar Pyr-ORS and equimolar citrate-based counterpart. METHODS: Eighty rats, using a fatal burn shock model, were randomized into four groups (two subgroups per group: n = 10): the sham group (group SR), Pyr-ORS group (group PR), WHO-ORS III group (group CR), and no rehydration group. ORS was delivered by manual gavage during 24 h following burns. Oral administration consisted of half of counted volume in the initial 8 h plus the rest in the later 16 h. Systemic hemodynamics, visceral organ surface blood flow, organ function, and metabolic acidosis were determined at 8 h and 24 h after burn. Another set of rats with identical surgical procedures without tests was observed for survival. RESULTS: Survival was markedly improved in the groups PR and CR; the former showed a higher survival rate than the latter at 24 h (40% versus 20%, P < 0.05). Systemic hemodynamics, visceral blood flow, and function of heart, liver, and kidney were greatly restored in group PR, compared with group CR (all P < 0.05). Hypoxic lactic acidosis was efficiently reversed in group PR, instead of group CR, (pH 7.36 versus 7.11, base excess 2.1 versus -9.1 mmol/L, lactate 4.28 versus 8.18 mmol/L; all P < 0.05) at 24 h after injury. CONCLUSIONS: Pyruvate was advantageous over citrate in low-osmolar ORS for protection of organs and survival; pyruvate, but not citrate, in the ORS corrected hypoxic lactic acidosis in rats subjected to lethal burn shock in 24 h.

Pyruvate in oral rehydration salt improves hemodynamics, vasopermeability and survival after burns in dogs.

BACKGROUND: To investigate whether pyruvate-enriched oral rehydration solution (Pyr-ORS), compared with citrate-enriched ORS (Cit-ORS), improves hemodynamics and organ function by alleviating vasopermeability and plasma volume loss during intra-gastric fluid rehydration in dogs with severe burn. METHODS: Forty dogs subjected to severe burn were randomly divided into four groups (n=10): two oral rehydrated groups with Pyr-ORS and Cit-ORS (group PR and group CR), respectively, according to the Parkland formula during the first 24h after burns. Other two groups were the intravenous (IV) resuscitation (group VR) with lactated Ringer's solution with the same dosage and no fluid rehydration (group NR). During the next 24h, all groups received the same IV infusion. The hemodynamics, plasma volume, vasopermeability and water contents and function of various organs were determined. Plasma levels of vascular endothelial growth factor (VEGF) and platelet activating factor (PAF) were detected by ELISA. RESULTS: Hemodynamics parameters were significantly improved in group PR superior to group CR after burns. Levels of VEGF and PAF were significantly lower in group PR than in group CR. Organ function parameters were also greatly preserved in group PR, relative to groups CR and NR. Lactic acidosis was fully corrected and survival increased in group PR (50.0%), compared to group CR (20.0%). CONCLUSION: Pyr-ORS was more effective than Cit-ORS in improving hemodynamics, visceral blood perfusion and organ function by alleviating vasopermeability-induced visceral edema and plasma volume loss in dogs with severe burn.

UV-Light-Induced Improvement of Fluorescence Quantum Yield of DNA-Templated Gold Nanoclusters: Application to Ratiometric Fluorescent Sensing of Nucleic Acids.

The use of DNA as a template has been demonstrated as an effective method for synthesizing different-sized silver nanoclusters. Although DNA-templated silver nanoclusters show outstanding performance as fluorescent probes for chemical sensing and cellular imaging, the synthesis of DNA-stabilized gold nanoclusters (AuNCs) with high fluorescence intensity remains a challenge. Here a facile, reproducible, scalable, NaBH4-free, UV-light-assisted method was developed to prepare AuNCs using repeats of 30 adenosine nucleotides (A30). The maximal fluorescence of A30-stabilized AuNCs appeared at 475 nm with moderate quantum yield, two fluorescence lifetimes, and a small amount of Au(+) on the surface of the Au core. Results of size-exclusion chromatography revealed that A30-stabilized AuNCs were more compact than A30. A series of control experiments showed that UV light played a dual role in the reduction of gold-ion precursors and the decomposition of citrate ions. A30 also acted as a stabilizer to prevent the aggregation of AuNCs. In addition, single-stranded DNA (ssDNA) consisting of an AuNC-nucleation sequence and a hybridization sequence was utilized to develop a AuNC-based ratiometric fluorescent probe in the presence of the double-strand-chelating dye SYBR Green I (SG). Under conditions of single-wavelength excitation, the combination of AuNC/SG-bearing ssDNA and perfectly matched DNA emitted fluorescence at 475 and 525 nm, respectively. The formed AuNC/SG-bearing ssDNA enabled the sensitive, selective, and ratiometric detection of specific nucleic acid targets. Finally, the AuNC-based ratiometric probes were successfully applied to determine specific nucleic acid targets in human serum.

CD133 expression in osteosarcoma and derivation of CD133⁺ cells.

Cluster of differentiation 133 (CD133) is recognized as a stem cell marker for normal and cancerous tissues. Using cell culture and real­time fluorescent polymerase chain reaction, CD133 expression was analyzed in osteosarcoma tissue and Saos­2 cell lines. In addition, cancer stem cell­related gene expression in the Saos­2 cell line was determined to explore the mechanisms underlying tumorigenesis and high drug resistance in osteosarcoma. CD133+ cells were found to be widely distributed in various types of osteosarcoma tissue. Following cell culture, cells entered the G2/M and S cell cycle stages from G0/G1. Levels of CD133+ cells decreased to normal levels rapidly over the course of cell culture. Colony forming efficiency was higher in the CD133+ compared with the CD133­ subpopulation of Saos­2 cells. Expression levels of stem cell­related genes, including multidrug resistance protein 1 (MDR1) and sex determining region Y­box 2 (Sox2) in the CD133+ subpopulation of cells were found to be significantly higher compared with the CD133­ subpopulation. These observations indicate that CD133+ Saos­2 cells exhibit stem cell characteristics, including low abundance, quiescence and a high potential to undergo differentiation, as well as expression of key stem cell regulatory and drug resistance genes, which may cause osteosarcoma and high drug resistance.

[An experimental study on the prevention of enteral bacterial translocation in scalded rats by smectite powder].

OBJECTIVE: To explore the preventive and treatment effects of smectite powder on enteral bacterial translocation in scalded rats. METHODS: Fifty-four Sprague-Dawley (SD) rats were randomly divided into three groups, i.e. normal control (A, n = 6), burn control (B, n = 24), and burn treatment (T, n = 24) groups. The rats in B and T groups were fed with tracing bacteria JM109, which was transfected with PUC19 plasmid in advance. The rats were subjected to 30% TBSA scald injury after the plasmid was shown to have colonized in the intestine. Smectite powder (0.6 g/day/kg) was fed to rats of T group immediately after the scalding, while those in B group received no smectite powder. Bacterial translocation in blood and mesenteric lymph nodes in all groups was observed and identified by enzyme digestion at 12 post scald hour (PSH) and on 1, 3 and 5 post-scald days (PSD). The contents of malondialdehyde (MDA) and superoxide dismutase (SOD) were determined in rat intestinal tissue. And the degree of injury to the entire small intestine was observed pathologically. The villus height of intestinal mucosa was measured, and the rate of epithelial nuclear splitting of mucosal crypts was calculated. RESULTS: The number of rats with positive blood bacterial culture in B group was obviously higher than that in A and T groups (P < 0.05) on 1 and 5 PSD. The bacterial quantity in mesenteric lymph nodes (MLN) in T group on 1 PSD (38 +/- 16 CFU/g) and 5 PSD (68 +/- 20 CFU/g) were obviously lower than those in B group (228 +/- 67 vs 183 +/- 29 CFU/g, P < 0.05). There was significant difference in the intestinal contents of MDA and SOD between B and T groups at each time point (P < 0.05). The rat jejunum villus height and the epithelial nuclear splitting in the small intestine mucosa in T group were evidently higher than those in B group (P < 0.05 or 0.01). CONCLUSION: Smectite powder is beneficial to the protection of the intestinal mucosa in scalded rats, and can effectively prevent postburn intestinal bacterial translocation in rats.

[Clinical study on the relationship among the dermis, fat dome and postburn hyperplastic scar formation].

OBJECTIVE: To explore the influence of dermal defect and fat dome structure destruction in burn wounds on the formation of hyperplastic scar. METHODS: Fifty two wounds in 24 burn patients with deep partial thickness burn indicating tangential excision in the extremities were enrolled in the study, and they were divided into three groups according to the extent of exposure of dermal fat granules, i.e. A (without fat exposure), B (with little fat exposure) and C (with much fat exposure) groups. These three groups were subdivided into A1 (without grafting), A2 (grafting with razor thin skin), B1 (without grafting), B2 (with razor thin skin grafting), C1 (without grafting) and C2 (with split-thickness skin grafting) groups, with 9 wounds in each group. The dermal depth and exposure rate of the fat granules in each group were measured and analyzed by KS400 photography analysis apparatus. The follow-up conditions of the scars 6 months after operation were evaluated with Vancouver remark system by Vancouver score assessment. RESULTS: There was obvious difference in the dermal depth and exposure rate of the fat granules among all the groups (P < 0.05 or 0.01). The fat exposure rate was positively correlated with the extent of the dermal defect (gamma = 0.554, P < 0.05). The Vancouver score in group A was lower than that in B and C groups (P < 0.05), while that in B1 group (3.714 +/- 2.498) was evidently higher than that in other groups (P < 0.01). The scar score was lowered when the wounds were grafted with the dermis with its thickness similar to the depth of the defect, The scar score was increased along with the elevation of fat exposure rate (P < 0.05). CONCLUSION: There was a positive correlation between the degree of dermal defect and that of hyperplastic scar after burns. The disruption of fat dome structure might also be an important factor in the scar development.