Subsidence Performance of the Bioactive Glass-Ceramic (CaO-SiO2-P2O5-B2O3) Spacer in Terms of Modulus of Elasticity and Contact Area: Mechanical Test and Finite Element Analysis.

OBJECTIVE: The objective of this study is to evaluate the subsidence performance of a bioactive glass-ceramic (CaO-SiO2-P2O5-B2O3) spacer in terms of its modulus of elasticity and contact area using mechanical tests and finite element analysis. METHODS: Three spacer three-dimensional models (Polyether ether ketone [PEEK]-C: PEEK spacer with a small contact area; PEEK-NF: PEEK spacer with a large contact area; and Bioactive glass [BGS]-NF: bioactive glass-ceramic spacer with a large contact area) are constructed and placed between bone blocks for compression analysis. The stress distribution, peak von Mises stress, and reaction force generated in the bone block are predicted by applying a compressive load. Subsidence tests are conducted for three spacer models in accordance with ASTM F2267. Three types of blocks measuring 8, 10, and 15 pounds per cubic foot are used to account for the various bone qualities of patients. A statistical analysis of the results is conducted using a one-way Analysis of variance and post hoc analysis (Tukey's Honestly Significant Difference) by measuring the stiffness and yield load. RESULTS: The stress distribution, peak von Mises stress, and reaction force predicted via the finite element analysis are the highest for PEEK-C, whereas they are similar for PEEK-NF and BGS-NF. Results of mechanical tests show that the stiffness and yield load of PEEK-C are the lowest, whereas those of PEEK-NF and BGS-NF are similar. CONCLUSIONS: The main factor affecting subsidence performance is the contact area. Therefore, bioactive glass-ceramic spacers exhibit a larger contact area and better subsidence performance than conventional spacers.

Kyphoplasty versus vertebroplasty: restoration of vertebral body height and correction of kyphotic deformity with special attention to the shape of the fractured vertebrae.

STUDY DESIGN: Retrospective comparative analysis. OBJECTIVE: We analyzed kyphosis correction, vertebral height restoration, and bone cement leakage in patients treated by vertebroplasty (VP) and kyphoplasty (KP) to compare the effectiveness of VP and KP for the treatment of osteoporotic vertebral compression fractures. SUMMARY OF BACKGROUND DATA: Superior results have been reported for the use of KP for kyphotic deformity correction and collapsed vertebral height restoration. However, there are no previous comparative reports comparing the efficacy of KP versus VP according to the shapes of fractured vertebrae. METHODS: A total of 103 patients underwent either VP (n=58) or KP (n=45) for treatment of osteoporotic vertebral compression fracture between October 2006 and September 2009. We organized the patients into 6 groups according to treatment method and fracture type: VP (wedge-shaped), VP (V-shaped), VP (flat-shaped), KP (wedge-shaped), KP (V-shaped), and KP (flat-shaped). Comparisons were performed for kyphosis correction, vertebral height restoration, and cement leakage between VP and KP groups. RESULTS: KP was more effective than VP, especially for middle column height restoration and bone cement leakage prevention, for all fracture types (P value <0.05). In addition, KP was more effective in anterior height restoration and kyphosis correction in both flat and wedge-shape fractures (P value <0.05). However, posterior column vertebral height was not restored in either the KP group or the VP group. The clinical outcomes did not differ between the 2 groups (P value >0.05). CONCLUSIONS: KP has a significant advantage over VP in terms of kyphosis correction, vertebral height restoration, and cement leakage prevention. KP has an obvious advantage in terms of middle vertebral height restoration and cement leakage prevention, especially for V-shape compression fractures.

Self-crosslinkable hyaluronate-based hydrogels as a soft tissue filler.

With increasing interest in aging and skin care, the use of fillers to increase the volume of soft tissue volume is increasing globally. However, the side effects caused by the residual chemical crosslinking agents present in these fillers limit the effective application of commercialized filler products. Therefore, the development of a novel crosslinking system with a non-toxic chemical crosslinking agent is required to overcome the limitations of commercial hyaluronate (HA)-based fillers. In this paper, a new injectable hydrogel with enhanced mechanical properties, tissue adhesion, injectability, and biocompatibility is reported. The HA derivatives modified with catechol groups (HA-DA) were crosslinked by self-oxidation under in vivo physiological conditions (pH 7.4) without chemical crosslinkers to form hydrogels, which can be further accelerated by the dissolved oxygen in the body. The fabricated HA-DA filler showed excellent mechanical properties and could be easily injected with a low injection force. Further, the HA-DA filler stably attached to the injection site due to the tissue adhesion properties of the catechol groups, thus leading to an improved displacement stability. In addition, the HA-DA filler showed excellent cell viability, cell proliferation, and biocompatibility. Therefore, the HA-DA hydrogel is a novel soft tissue filler with great potential to overcome the limitations of commercial soft tissue fillers.

Which Is More Predictive Value for Mechanical Complications: Fixed Thoracolumbar Alignment (T1 Pelvic Angle) Versus Dynamic Global Balance Parameter (Odontoid-Hip Axis Angle).

OBJECTIVE: In this study, we investigate about relationship between postoperative global sagittal imbalance and occurrence of mechanical complications after adult spinal deformity (ASD) surgery. In global sagittal balance parameters, odontoid-hip axis (OD-HA) angle and T1 pelvic angle (TPA) were analyzed. METHODS: Between January 2009 and December 2016, 199 consecutive patients (26 males and 173 females) with ASD underwent corrective fusion of more than 4 levels and were followed up for more than 2 years. Immediate postoperative and postoperative 2 years whole spine x-rays were checked for evaluating immediate postoperative OD-HA, TPA, and other parameters. In clinical outcomes, back and leg pain visual analogue scale, Scoliosis Research Society-22 spinal deformity questionnaire (SRS-22), Oswestry Disability Index (ODI), 36- item Short Form Health Survey (SF-36) were evaluated. RESULTS: Based on the occurrence of mechanical complications, a comparative analysis was performed for each parameter. In univariable analysis, mechanical complications were significantly much more occurred in OD-HA abnormal group (odds ratio [OR], 3.296; p < 0.001; area under the curve [AUC] = 0.645). In multivariable analysis, the result was much more related (OR, 2.924; p = 0.001; AUC = 0.727). In contrast, there was no significant difference between normal and the occurrence of mechanical complications in TPA. In clinical outcomes (normal vs. abnormal), the differences of SRS-22 (0.88 ± 0.73 vs. 0.68 ± 0.64, p = 0.042), ODI (-24.72 ± 20.16 vs. -19.01 ± 19.95, p = 0.046), SF-36 physical composite score (19.33 ± 18.55 vs. 12.90 ± 16.73, p = 0.011) were significantly improved in OD-HA normal group. CONCLUSION: The goal of ASD surgery is to improve patient life quality through correction. In our study, TPA was associated with spinopelvic parameter and OD-HA angle was associated with health-related quality of life and complications. OD-HA angle is predictable factor for mechanical complications after ASD surgery.

The biological effects of topical alginate treatment in an animal model of skin wound healing.

Wound healing is a dynamic and complex process of tissue repair that involves a number of cellular and molecular events. It proceeds from inflammatory response to reepithelialization and finally to formation of a permanent scar. Alginate is a polymer of guluronic and mannuronic acid that is used as a scaffolding material in biomedical applications. For the purpose of studying wound healing, full-thickness skin defects were produced on the dorsal area in rats. We measured the relative sizes of the wounds on days 3, 5, 7, 14, and 28. The wound sizes were decreased in the alginate-treated group compared with the control group and the vaseline-treated group. The expressions of transforming growth factor-beta1, fibronectin, and vascular endothelial growth factor were significantly decreased in the alginate-treated group compared with the control group, while the expression of collagen-I was increased in the alginate-treated group, as indicated by Western blotting and immunohistochemical staining. These data suggest that alginate has significant wound healing promoting activity. The results from the present study indicate that the effect of alginate on wound healing may involve biological mechanisms associated with the expression of transforming growth factor-beta1, fibronectin, vascular endothelial growth factor, and collagen-I.

Pectin-like acidic polysaccharide from Panax ginseng with selective antiadhesive activity against pathogenic bacteria.

Previous studies have revealed the inhibitory effects of an acidic polysaccharide purified from the root of Panax ginseng against the adhesion of Helicobacter pylori to gastric epithelial cells and the ability of Porphyromonas gingivalis to agglutinate erythrocytes. In this study, this acidic polysaccharide from P. ginseng, PG-F2, was investigated further, in order to characterize its antiadhesive effects against Actinobacillus actinomycetemcomitans, Propionibacterium acnes, and Staphylococcus aureus. The minimum inhibitory concentrations (MIC) were found to be in a range of 0.25-0.5mg/mL. However, results showed no inhibitory effects of PG-F2 against Lactobacillus acidophilus, Escherichia coli, or Staphylococcus epidermidis. PG-F2 is a pectin-type polysaccharide with a mean MW of 1.2 x 10(4) Da, and consists primarily of galacturonic and glucuronic acids along with rhamnose, arabinose, and galactose as minor components. The complete hydrolysis of PG-F2 via chemical or carbohydrolase enzyme treatment resulted in the abrogation of its antiadhesive activity, but limited hydrolysis via treatment with pectinase (EC. 3.2.1.15) yielded an oligosaccharide fraction, with activity comparable to the precursor PG-F2 (the MIC of ca. 0.01 mg/mL against H. pylori and P. gingivalis). Our results suggest that PG-F2 may exert a selective antiadhesive effect against pathogenic bacteria, while having no effects on beneficial and commensal bacteria.

Protective effect of bioactive ceramics on liver injury: regulation of pro-inflammatory cytokins expression.

AIM OF STUDY: A bioactive ceramics has been reported to regulate the expression of inflammatory cytokines in macrophage cells activated by lipopolysaccharides (LPS). In present study, we investigated the anti-inflammatory effect of bioactive ceramics using liver injury model in mouse. MATERIALS AND METHODS: Mice were divided into three groups: Normal group, LPS group (LPS and no ceramics treatment), Ceramics group (LPS and ceramics treatment). RESULTS: LPS administration induced the increase of plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in mouse. The losses of cytoplasm of hepatocytes due to LPS caused the increase of AST and ALT in mouse plasma. In Ceramics group, however, the concentration of AST and ALT were much lower than LPS group until 6 weeks. And the losses of cytoplasm were rarely seen in Ceramics group. RT-PCR results showed that the decrease of proinflammatory cytokines such as IL-1beta and IL-6 was observed in Ceramics group. Moreover, TGF-beta1 and VEGF expression was increased in Ceramics group. CONCLUSION: Bioactive ceramics effectively protected endotoxin-induced liver injury by attenuation of inflammatory processes in mice.

In vitro anti-adhesive activity of an acidic polysaccharide from Panax ginseng on Porphyromonas gingivalis binding to erythrocytes.

A polysaccharide with high uronic acid content from the roots of Panax ginseng was found to inhibit the ability of Porphyromonas gingivalis to agglutinate erythrocytes. This polysaccharide showed a strong inhibitory activity (minimum inhibitory concentration 0.25 mg/mL), but treatment with pectinase resulted in non-inhibitory hydrolyzed products. In contrast, the inhibition by the acidic polysaccharide from the leaves of Artemisia capillaris was negligible. The carbohydrate composition of the two polysaccharides indicated that the anti-adhesive activity may be correlated with glucuronic acid content, one of the components of glycosaminoglycans. Low molecular weight heparin and sucrose octasulfate revealed stronger inhibitory effects on bacterial binding, than the acidic polysaccharide from P. ginseng.