Citrate Improves Biomimetic Mineralization Induced by Polyelectrolyte-Cation Complexes Using PAsp-Ca&Mg Complexes.

Magnesium ions are highly enriched in early stage of biological mineralization of hard tissues. Paradoxically, hydroxyapatite (HAp) crystallization is inhibited significantly by high concentration of magnesium ions. The mechanism to regulate magnesium-doped biomimetic mineralization of collagen fibrils has never been fully elucidated. Herein, it is revealed that citrate can bioinspire the magnesium-stabilized mineral precursors to generate magnesium-doped biomimetic mineralization as follows: Citrate can enhance the electronegativity of collagen fibrils by its absorption to fibrils via hydrogen bonds. Afterward, electronegative collagen fibrils can attract highly concentrated electropositive polyaspartic acid-Ca&Mg (PAsp-Ca&Mg) complexes followed by phosphate solution via strong electrostatic attraction. Meanwhile, citrate adsorbed in/on fibrils can eliminate mineralization inhibitory effects of magnesium ions by breaking hydration layer surrounding magnesium ions and thus reduce dehydration energy barrier for rapid fulfillment of biomimetic mineralization. The remineralized demineralized dentin with magnesium-doped HAp possesses antibacterial ability, and the mineralization mediums possess excellent biocompatibility via cytotoxicity and oral mucosa irritation tests. This strategy shall shed light on cationic ions-doped biomimetic mineralization with antibacterial ability via modifying collagen fibrils and eliminating mineralization inhibitory effects of some cationic ions, as well as can excite attention to the neglected multiple regulations of small biomolecules, such as citrate, during biomineralization process.

Evaluation of toxicity of polystyrene microplastics under realistic exposure levels in human vascular endothelial EA.hy926 cells.

Microplastics (MPs) have emerged as a global concern, with a recent study being the first to detect them in the bloodstream of healthy people. However, precise information regarding the toxic effects of MPs on the human vascular system is currently lacking. In this study, we used human vascular endothelial EA. hy926 cells to examine the toxic potential of polystyrene MPs (PSMPs) under realistic blood concentrations. Our findings indicated that PSMPs can cause oxidative stress by reducing the expression of antioxidants, thereby leading to apoptotic cytotoxicity in EA. hy926 cells. Furthermore, the protective potential of heat shock proteins can be reduced by PSMPs. PSMP-induced apoptosis might also lower the expression of rho-associated protein kinase-1 and nuclear factor-κB expression, thus dampening LRR- and pyrin domain-containing protein 3 in EA. hy926 cells. Moreover, we observed that PSMPs induce vascular barrier dysfunction via the depletion of zonula occludens-1 protein. However, although protein expression of the nuclear hormone receptor 77 was inhibited, no significant increase in ectin-like oxidized low-density lipoprotein receptor-1 was noted in PSMP-treated EA. hy926 cells. These results demonstrate that exposure to PSMPs may not sufficiently increase the risk of developing atherosclerosis. Overall, our research signifies that exposure to realistic blood concentrations of PSMPs is associated with low atherosclerotic cardiovascular risk in humans.

[Effect of low-intensity pulsed ultrasound on periodontitis in Beagle dogs].

OBJECTIVE: To investigate the effect of low intensity pulsed ultrasound (LIPUS) on periodontitis in Beagle dogs. METHODS: The animal model of chronic periodontitis was established with elastic ligature-induced alveolar bone defect in Beagle dogs. LIPUS with different intensity (50 mW/cm2, 100 mW/cm2) pulse wave and 50 mW/cm2 continuous wave, 1.5 MHz of frequency, 200 micros of pulse width modulated signal, and 1 kHz of repetition rate were applied to the dogs for 8 weeks (once a day and 20 minutes every time). The periodontal clinical examinations and histological biopsy were performed. RESULTS: With increased exposure to LIPUS, gum tissue swelling of the dogs was reduced. The plaque index (PLI), gingival index (GI), pocket depth (PD) of the treatment groups were lower than the control groups (P < 0.05). No significant gingival recession, attachment loss or furcation was found. The histological examination revealed that there was no obvious gingival hyperplasia in epithelial tissues, but there were significant activities in relation to collagen formation, decrease of bone resorption, and generation of active osteoblasts. CONCLUSION: LIPUS may help repair periodontal tissues and should be considered in guided tissue regeneration (GTR).

More advantages of trocar compared than steel needle in deep venipuncture catheterization.

BACKGROUND: Deep venipuncture catheterization is widely used in clinical anesthesia. However, it is worth thinking about how to improve the rate of successful catheter insertion, and relieve patients' discomfort. This paper aimed to compare the clinical advantages between trocar and steel needle. METHODS: Total 503 adult patients were recruited and randomly assigned. The control group was punctured with steel needle, and the experimental group was punctured with trocar needle. Clinical and followed-up information was recorded. Pearson's chi-squared and spearman test were performed to analyze the correlation between intervention and relative parameters. Univariate logistic regression was performed to verify the odds ratio of trocar needle compared with steel needle. RESULTS: Pearson's chi-square test and Spearman's correlation test showed a significant correlation between puncture success, puncture comfort, successful catheter insertion, puncture time, thrombosis, catheter fever, bleeding, infection and interventions (P < .05). Univariate logistic regression showed that there existed better puncture comfort (odds ratio [OR] = 6.548, 95% confidence interval [CI]: 4.320-9.925, P < .001), higher successful catheter insertion (OR = 6.060, 95% CI: 3.278-11.204, P < .001), shorter puncture time (OR = 0.147, 95% CI: 0.093-0.233, P < .001), lesser thrombosis (OR = 0.194, 95% CI: 0.121-0.312, P < .001), lesser catheter fever (OR = 0.263, 95% CI: 0.158-0.438, P < .001), lesser bleeding (OR = 0.082, 95% CI: 0.045-0.150, P < .001) and lesser infection (OR = 0.340, 95% CI: 0.202-0.571, P < .001) in trocar group compared with steel needle group. CONCLUSION: Trocar application in deep venipuncture catheterization can improve successful catheter insertion, relieve pain and discomfort of patients, reduce incidence of complications, and provide better security for patients.

Hydroxyapatite-incorporation improves bone formation on endosseous PEEK implant in canine tibia.

BACKGROUND: Poly Ether Ether Ketone (PEEK) has been considered as a potential alternative material for endosseous dental implants, for its low elastic modulus, biocompatibility, and low cost in customized device manufacture. Hydroxyapatite-incorporation is supposed to improve the poor osseointegration of PEEK. METHODS: In the present study we analyzed the in vivo response of hydroxyapatite-incorporated PEEK (PEEK-HA) implants in canine tibia. PEEK-HA and PEEK implants were implanted and were examined 4 weeks and 12 weeks after implantation with radiology and histology. Commercial titanium dental implants served as controls. RESULTS: The ratio of bone volume to tissue volume of PEEK-HA implants was higher than that of PEEK implants 4 weeks after implantation in the µ-CT analysis. The bone implant contact of PEEK and PEEK-HA implants showed no statistical difference in the histological examination, but newly-formed bone around PEEK-HA implants showed more signs of mineralization than that around PEEK implants. CONCLUSION: The study suggested that bone formation was improved with hydroxyapatite-incorporation in PEEK. Hydroxyapatite-incorporated PEEK implants may represent a potential material for endosseous dental implant.

Cholestyramine alters bile acid amounts and the expression of cholesterol-related genes in rabbit intestinal and hepatic tissues.

OBJECTIVE: Cholestyramine (CHO), as a bile acid sequestering exchange resin, has been widely used to treat hypercholesterolemia. The aim of this study was to explore how CHO regulated serum cholesterol amounts and bile acid levels in animal models. METHODS: New Zealand White rabbits were randomly assigned to the control (given distilled water) and CHO-treated (given CHO solution 1 g/kg per day for 2 weeks) groups. To assess bile acid pool size, bile fistulas were constructed in five rabbits in each group. Serum cholesterol levels and biliary and fecal bile outputs were determined. Liver cholesterol 7α-hydroxylase ( CYP7A1 ), small heterodimer partner ( SHP ), bile salt export pump ( BSEP ), ileal bile acid-binding protein ( IBABP ) and LDL receptor ( LDL-R ) mRNA expressions were assessed by real-time polymerase chain reaction. CYP7A1 activity was also determined. RESULTS: CHO treatment decreased serum cholesterol levels by 12.1%. Although CHO did not change the bile acid pool size and biliary bile acid output, it significantly increased fecal bile acid output. Interestingly, CHO also significantly increased the expression and activity of CYP7A1, as well as IBABP and LDL-R mRNA expressions, but decreased hepatic SHP and BSEP gene expressions. CONCLUSION: CHO markedly alters bile acid and cholesterol amounts in rabbit intestinal and liver tissues, downregulating genes responsible for cholesterol homeostasis.

[Repairing effects of low-intensity pulsed ultrasound on alveolar bone defects in Beagle dogs].

OBJECTIVE: To evaluate the potential repairing effects of low-intensity pulsed ultrasound (LIPUS) irradiation on acute horizontal alveolar bone defects at the mandibular pre-molar areas in Beagle dogs. METHODS: Horizontal alveolar bone defect models were established under enamelo-cemental junction 6 mm at the mandibular third and forth pre-molar buccal regions on both sides in 4 beagle dogs, and bilateral sides of each dog were randomly divided into two groups: Experimental groups with LIPUS irradiation (I(SATA) 30 mW X cm(-2), 20 min x d(-1)) and control groups without opening power source of LIPUS radiation. Dual energy X-ray bone densitometer was used to detect the bony density after an 8 weeks' irradiation. Meanwhile, decalcified bone tissue sections were used to assess the histological effects of new alveolar bone. RESULTS: The results of new bony density detection in experimental group and control group were (0.6053 +/- 0.0566) g x cm(-2), (0.6047 +/- 0.0552) g x cm(-2), respectively, and there was no statistical significance between the differences of the two groups (P = 0.9839). Hematoxylin-eosin staining of decalcified bone tissue sections demonstrated that there were more osteoblasts lining at the edge of new alveolar bone in the experimental groups than that scattered in the control groups, and Masson staining revealed that collagens in new alveolar bone stained bright red indicating higher maturity in the experimental groups, while in the control groups mainly stained blue with some virescent areas indicating lower maturity. CONCLUSION: LIPUS irradiation on acute horizontal alveolar bone defects has potential repairing effects.