Initiator-Free Photocuring 3D-Printable PVA-Based Hydrogel with Tunable Mechanical Properties and Cell Compatibility.

Poly(vinyl alcohol) (PVA)-based hydrogels have attracted great attention and been widely used in biological tissue engineering. With the development of modern medicine, precision medicine requires the customization of medical materials. However, lacking of photocurable functional groups or the performance of rapid phase transition makes PVA-based hydrogels difficult to be customizable molded through photocuring 3D printing technique. In this research, customizable PVA-based hydrogels with high performance through 3D photocurable printing and freezing-thawing (F-T) process are obtained. The ability of 3D-printable is endowed by the introduction of polyvinyl alcohol-styrylpyridine (PVA-SBQ), which can be photo-crosslinked quickly without photoinitiator. Meanwhile, the tunable mechanical properties are achieved by adjusting the mass ratio of PVA-SBQ to PVA, and PVA can offer the physical crosslinking points through freezing-thawing (F-T) process. The hydrogels with high resolution are prepared by digital light procession 3D printing with the mass ratio 1:1 of PVA-SBQ to PVA solution. Attributed to the absence of initiator, and no small molecule residues inside the hydrogels, the hydrogels have good biocompatibility and have the potential to be applicated in the field of biological tissue engineering.

Assessment of clinical, imaging, surgical risk factors for subsequent fracture following vertebral augmentation in osteoporotic patients.

INTRODUCTION: Currently, the risk factors for subsequent fracture following vertebral augmentation remain incomplete and controversial. To provide clinicians with accurate information for developing a preventive strategy, we carried out a comprehensive evaluation of previously controversial and unexplored risk factors. METHODS: We retrospectively reviewed patients with osteoporotic vertebral compression fracture in lumbar spine who received vertebral augmentation between January 2019 and December 2020. Based on whether refracture occurred, patients were assigned to refracture and non-refracture group. The clinical characteristics, imaging parameters (severity of vertebral compression, spinal sagittal alignment, degeneration of paraspinal muscles), and surgical indicators (cement distribution and leakage, correction of spinal sagittal alignment) were collected and analyzed. RESULTS: There were 128 patients and 16 patients in non-refracture and refracture group. The incidence of previous fracture, multiple fractures, and cement leakage were notably higher, relative cross-sectional area of psoas (r-CSAPS) was significantly smaller, CSA ratio, fatty infiltration of erector spinae plus multifidus (FIES+MF), FIPS, postoperative lumbar lordosis (post-LL), correction of body angel (BA), and LL were significantly greater in refracture group. Binary logistic regression analysis revealed previous fracture, cement leakage, post-LL, and correction of BA were independent risk factors. According to the ROC curve, correction of BA showed the highest prediction accuracy, and the critical value was 3.45°. CONCLUSIONS: The occurrence of subsequent fracture might be the consequence of multiple factors. Previous fracture, cement leakage, post-LL, and correction of BA were identified as independent risk factors. Furthermore, the correction of BA should not exceed 3.45°, especially in patients with risk factors.

Expression of endoplasmic reticulum stress protein in rabbit condyle cartilage following anterior disk displacement.

OBJECTIVE: Anterior disk displacement (ADD) is a most common subtype of temporomandibular disorders (TMD), which is promoted by chondrocytes apoptosis. However, the signaling pathways that trigger apoptosis are still unknown. The aim of this study was to investigate the expression of endoplasmic reticulum (ER) stress-related proteins in the condylar cartilage of rabbits following ADD. METHODS: Sixty healthy adult rabbits were randomly assigned to the experimental and sham-operated control groups (n = 12). The experimental rabbits were subjected to surgical ADD in the right temporomandibular joints. The production of ER stress-related proteins C/EBP homologous protein (CHOP), glucose-regulated protein 78 (GRP78), cleaved caspase-3, and caspase-12 in cartilage was evaluated by immunohistochemistry, quantitative real-time PCR, and Western blot analysis. RESULTS: Our results showed that the expression of CHOP, GRP78, cleaved caspase-3, and caspase-12 increased significantly along with degenerative changes in cartilage after ADD. CONCLUSION: These results indicate that the ER stress pathway is activated in ADD cartilage and might promote the development of TMD.

[Preparation and evaluation of Shedan in situ forming gel based on ocular characteristics].

To develop an ophthalmic preparation of Shedan, an in situ forming gel was prepared with the formulation containing 18% of poloxamer 407 and 5% of poloxamer 188 by response surface designs plus central composite designs. The rheology results showed that LVE range gamma should limited within 0.5%, Shedan high-frequency region, and the thixotropy recovery time is less than 5 seconds. The phase transition temperature was 33.25 °C according to curve of storage modulus and loss modulus determined by temperature scanning. Surface tension and osmometer of it determined by surface tension meter and dew point osmometer were 36.43 mN · m(-1), and 320.6 mOsm · kg(-1), respectively. Fluorescein sodium was selected as the marker to monitor the corneal residence time, and the results showed that Shedan gel could prolong drug residence for 180 min. In line with zero-order kinetics, releases of muscone and salvianolic acid B in vitro depends on gels erosion. The results of rabbit ocular irritation experiments suggested that Shedan in situ forming gel was biocompatible and nonirritant. In conclusion, a novel Shedan in situ forming gel was developed and characterized for potential drug treatment of retinal vein occlusion.

A randomized double-blind placebo-controlled study of the efficacy of Clinpro XT varnish and Gluma dentin desensitizer on dentin hypersensitivity.

PURPOSE: To evaluate the effect of Clinpro XT Varnish (VXT) paste-liquid, resin-modified glass-ionomer and the resinous dentin desensitizing varnish and Gluma Dentin Desensitizer (Gluma) in treating dentin hypersensitivity (DH). METHODS: This short-term (4-week) randomized, double-blind, placebo-controlled, split-mouth study included a total of 119 teeth from 31 individuals which were randomized into three groups: VXT, Gluma, and placebo (warm water). Dentin sensitivity was evaluated by subjects' perception of DH determined by pretreatment tooth sensitivity score (TSS) measured on a 0-10 visual analogue scale (VAS) after tactile (probe) or thermal/evaporative (blast of air) stimuli. TSS was scored at baseline, immediately after treatment (Day 0), after 1 week and after 4 weeks. RESULTS: For both stimuli, mean TSS was significantly decreased in the VXT and Gluma groups at all time points (all, P < 0.001) compared with baseline. Regarding comparisons of TSS between treatment groups, the VXT group had significantly lower mean TSS compared with the Gluma group (P< 0.05) and placebo control group (P< 0.05) at all time points after treatment regardless of stimuli. Group Effect, Time Effect, and Group x Time Effect were all significantly different (all, P < 0.001).

Biomechanical analysis of single- and double-level cervical disc arthroplasty using finite element modeling.

Recently, many different types of artificial discs have been introduced to persevere the biomechanical behavior of the cervical spine. This study compares the biomechanical behavior of single- and double-level cervical disc arthroplasty, that is "Prestige LP and Mobi-C" on the index and adjacent segment. A three-dimension finite element model of C2-C7 was developed and validated. In single-level prostheses, the Prestige LP or Mobi-C was implanted in the segment C5-C6, while the double-level arthroplasty was integrated at both segments C4-C5 and C5-C6 in the FE model. The intact FE and prosthesis-modified models were constrained from the inferior endplate of the vertebra C7 and applied a compressive load of 73.6 N with a moment load of 1 Nm on the odontoid process of the vertebra C2 to produce flexion/extension, lateral bending, and axial rotation. The prosthesis-modified model's range of motion and intradiscal pressure were determined and compared to the intact model. Also examined the impact of the prostheses on the stress at the bone-implant interface. The range of motion of the implanted segments in both single- and double-levels arthroplasty was increased while that of the adjacent segment of implanted segments decreased. The intradiscal pressure in both levels of arthroplasty was greater than in the intact model. In conclusion, Mobi-C's cervical prostheses could better preserve the normal range of motion and maintain intradiscal pressure than the Prestige LP.

[Application of sulfylated calcium alginate composite hydrogel loaded with zinc-based zeolite imidazole for the treatment of periodontitis].

PURPOSE: To explore the feasibility of adhesive thiomer calcium alginate composite hydrogel (ZIF-8@CHA-SH) containing metal-organic framework for the treatment of periodontitis in rats. METHODS: Preparation and characterization of ZIF-8@CHA-SH were performed, and the morphology and chemical composition were observed. The antibacterial properties were detected by plate coating method and scanning electron microscope. CCK-8 and live/dead cell fluorescence staining were used to evaluate the toxicity of ZIF-8@CHA-SH on gingival fibroblasts. The anti-inflammatory and tissue repair promoting effects of ZIF-8@CHA-SH were verified by animal experiments. GraphPad Prism 7.0 software was used for statistical analysis. RESULTS: The successful synthesis of ZIF-8@CHA-SH was proved by scanning electron microscopy, energy spectrum analysis, Fourier transform infrared spectroscopy and X-ray diffraction. ZIF-8@CHA-SH had excellent antibacterial ability, and the antibacterial rates against Escherichia coli, Staphylococcus aureus and Streptococcus mutans were (99.88±0.12)%, (99.81±0.32)% and (95.53±3.08)%, respectively（P<0.001）. The cell viability rate of ZIF-8@CHA-SH was (91.64±3.66)% after 5 days of co-culture with human gingival fibroblasts (P=0.6). In vivo experiments showed that ZIF-8@CHA-SH could reduce the infiltration of inflammatory cells and the expression of pro-inflammatory factor IL-6 in rats with periodontitis. CONCLUSIONS: ZIF-8@CHA-SH has excellent biological performance, which can effectively treat periodontitis caused by bacteria, and provids a new strategy for the treatment of periodontal diseases in the future.

A meta-analysis of complications associated with the use of cement-augmented pedicle screws in osteoporosis of spine.

PURPOSE: Our study aimed to provide updated and comprehensive evidence on the complications associated with the use of cement-augmented pedicle screws (CAPS) in osteoporosis patients undergoing spinal instrumentation. METHODS: Databases of PubMed, Embase, Ovoid, and Google Scholar were screened from January 2000-February 2020 for studies reporting complications of CAPS in osteoporosis patients. Pooled estimates (with 95% confidence intervals) were calculated. RESULTS: Twenty studies were included. The pooled risk of screw loosening, screw breakage and screw migration was 2.0% (0.2%-4.9%), 0.6% (0%-2.0%) and 0.2% (0%-1.2%) respectively. On pooling of data from 1277 patients, we found the risk of all cement leakage to be 21.8% (6%-43.1%). However, data from 1654 patients indicated the risk of symptomatic cement leakage was 1.2% (0.6%-1.9%). The incidence of pulmonary embolism was 3.0% (0.5%-6.8%) while the risk of symptomatic pulmonary embolism was 0.8% (0.2%-1.5%). Pooled risk of neurovascular complications was 1.6% (0.3%-3.6%), adjacent compression fracture was 3.3% (1.2%-6.2%) and infectious complications was 3.1% (1.1%-5.7%). There were high heterogeneity and variability in the study outcomes. CONCLUSION: The incidence of screw-related complications like loosening, breakage, and migration with the use of CAPS in spinal instrumentation of osteoporotic patients is low. The risk of cement leakage is high and variable but the incidence of symptomatic cement leakage and related neurovascular or pulmonary complications is low. Further studies using homogenous methods of reporting are needed to strengthen current evidence. LEVEL OF EVIDENCE: II, Systematic Review and Meta-analysis.

[Preparation and characterization of non-ionic surfactant vesicle of cantharidin].

OBJECTIVE: To study the preparation of cantharidin entrapped non-ionic surfactant vesicle (noisome)and evaluate its quality. METHOD: The niosome loaded with cantharidin was prepared using injection method by non-ionic surfactants as the carrier. An centrifugation separation method and HPLC analysis method of the cantharidin were established to detect the entrapment efficiency. The optimum preparation technology was established by a orthogonal experiment. The morphology, and particle size were studied to evaluate the preparation. RESULT: The average size of niosomes were (209. 8 +/- 0.5) nm. The entrapment efficiency of the CTD-NS was (27.5% +/- 2.0%) and Zeta potential was (41.5 +/- 0.65) mV. CONCLUSION: The preparation of cantharidin noisome by TweenA and SpanB is practicable and successful. These experiments can be the basement of developing targeting drug delivery system.

Role and mechanism of the nod-like receptor family pyrin domain-containing 3 inflammasome in oral disease.

OBJECTIVE: To summarize evidence and data from experimental studies regarding the role and mechanism of the Nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome in the pathogenesis of several representative oral diseases. MATERIALS AND METHODS: A literature search of PubMed and EBSCO was performed. The literature was searched using a combination of keywords, e.g., NLRP3 inflammasome, inflammation, microorganisms, oral inflammatory diseases, and oral immunological diseases. RESULTS: The initiation and activation of the NLRP3 inflammasome are associated with the pathogenesis and progression of several representative oral diseases, including periodontitis, oral lichen planus, dental pulp disease, and oral cavity squamous cell carcinoma. CONCLUSIONS: The NLRP3 inflammasome plays a crucial role in the progression of inflammatory and adaptive immune responses. The possible role of the NLRP3 inflammasome in several oral diseases, including not only periodontitis and pulpitis but also mucosal diseases and oral cavity squamous cell carcinoma, may involve the aberrant regulation of inflammatory and immune responses. Understanding the cellular and molecular biology of the NLRP3 inflammasome is necessary because the NLRP3 inflammasome may be a potential therapeutic target for the treatment and prevention of oral inflammatory and immunological diseases.

Improving acute cardiac transplantation rejection therapy using ultrasound-targeted FK506-loaded microbubbles in rats.

Targeted delivery of immunosuppressants to allografts can increase the concentrations of drugs in pathological tissues, improve therapeutic effects and reduce unfavorable side effects. Therefore, we synthesized FK506-loaded microbubbles (FK506-MBs) for site-specific release of FK506 into transplanted hearts by the ultrasound-targeted microbubble destruction (UTMD) technique. The average particle size of FK506-MBs was 1.65 ± 0.32 µm and they had high drug loading and encapsulation efficiency. The in vivo drug concentration in transplanted hearts that were treated with FK506-MBs plus UTMD was about 1.64-fold higher than that in grafts that received free FK506 at the same dosage. The degree of graft rejection in the FK506-MB plus UTMD group was lower than those of other groups. Both infiltration of T cells and secretion of inflammatory cytokines were significantly reduced in the FK506-MB plus UTMD group. More importantly, the mean survival time of the grafts was significantly longer (16.00 ± 0.89 day) than those of the PBS group (6.66 ± 1.36 day) and the FK506 group (12.83 ± 1.17 day). In addition, we also found that the concentration of FK506 in whole blood was lower in the FK506-MB plus UTMD group than that in the FK506 group, which would be beneficial for reducing the side effects. Hence, our results showed that combining FK506-MBs with UTMD was an effective strategy to deliver FK506 to transplanted hearts, which can increase the local drug concentration and enhance its efficacy on rejection. Ultrasound-targeted drug release is safe and radiation-free, with great potential for clinical transformation, and could also be extended to the treatment of other graft rejection cases, such as liver transplantation, kidney transplantation and so on.

Identification of a novel missense mutation of MSX1 gene in Chinese family with autosomal-dominant oligodontia.

OBJECTIVES: Oligodontia is defined as the congenital absence of 6 or more permanent teeth excluding the third molar. The occurrence of non-syndromic still remains poorly understood, but in recent years some cases have been reported where mutations or polymorphisms of PAX9 and MSX1 had been associated with non-syndromic oligodontia. The objective of the present work was to study the phenotype and genotype of three generations of a Han Chinese family affected by non-syndromic autosomal-dominant oligodontia. DESIGN: We examined all individuals of the oligodontia family by clinical and radiographic examinations. Based on clinical manifestations, candidate genes MSX1 and PAX9 were picked up to analyse and screen mutations. RESULTS: Dental evaluation showed that the most commonly missing teeth are the mandibular second premolars, followed by the maxillary second premolars and maxillary lateral incisors, and subsequently the maxillary first premolars. The probability of missing a particular type of tooth is not always bilaterally symmetrical, and differences exist between maxilla and mandible. PCR-SSCP analysis and DNA sequencing revealed a novel missense mutation c.662C>A in a highly conserved homeobox sequence of MSX1 and a known polymorphisms c.347C>G. CONCLUSION: Our finding suggests the missense transversion (c.662C>A) and the polymorphisms (c.347C>G) may be responsible for oligodontia phenotype in this Chinese family.

[Comparative study on in vitro drug-release between Tuizhang ophthalmic gel and Tuizhang oculentum].

OBJECTIVE: To prepare tuizhang gel to cure cataract, the characteristics of Tuizhang gel on the drug-releasing in vitro were evaluated by compared with Tuizhang oculentum. METHOD: The emodin and chrysophanol in the releasing mediator were determined by HPLC, and the drug releasing characteristics of Tuizhang gel and Tuizhang oculentum were studied by bag filter method. RESULT: The emodin and chrysophanol in Tuizhang gel released (98.3, 1.1)%, (95.8, 1.8)% within 24 hours, respectively, while those in tuizhang oculentum released (10.62, 0.7)%, (10.46, 0.4)%, respectively. The emodin and chrysophanol in Tuizhang gel released more quickly and completely than in Tuizhang oculentum, so Tuizhang gel has enhanced the bioavailability. CONCLUSION: The Tuizhang gel is characterized by slow-release to some degree, and it shows a promising future on ophthalmic drug delivery.

Self-Assembled Thermoresponsive Nanogels Prepared by Reverse Micelle → Positive Micelle Method for Ophthalmic Delivery of Muscone, a Poorly Water-Soluble Drug.

This study aimed to design a nanocarrier ophthalmic delivery system of muscone, a poorly water-soluble drug. The muscone thermoresponsive nanogels were self-assembled by reverse micelle → positive micelle method. Muscone was demonstrated to have uniform narrow particle size distribution in nanogel by the dynamic light scattering test. The developed nanocomposite hydrogel had a high muscone loading, and the rheology results showed that the phase transition temperature was 34.05°C. Thixotropy test indicated that the nanogel was able to resist the blinking of eyes because of the thixotropy recovery time, which is <5 s. Compared with muscone eye drops, muscone nanogels showed longer retention time on the corneal surface using fluorescent labeling technology and produced a 3.4-fold increase in apparent permeability coefficients (Papp). Draize testing showed that the developed nanogel caused no eye irritation. In vivo pharmacokinetic study indicated that the nanogel could significantly increase the bioavailability of muscone after administration compared with eye drops. These results indicate that self-assembled thermoresponsive nanogel prepared by reverse micelle → positive micelle method has potential for the ophthalmic delivery of poorly water-soluble drugs.

[Relation analysis of phosphorus removal and BOD5 loading using PHB monitoring in A2/O process].

In a pilot-scale anaerobic-anoxic-oxic experimental system for municipal wastewater treatment, PHB consumption in an oxic tank and PHB production in an anaerobic tank had been monitored overtime, and relations among PHB consumption/production, phosphorus removal/release and BOD5 loading had been analyzed. The results indicated that the consumption of PHB was positively related with phosphorus removal, and about 140 mg PHB consumption could result in 1 mg P removal. In the anaerobic tank, about 1.17 mg P release could result in 100 mg PHB production. The PHB production at the loading of 0.176 g/(g x d) was 4 mg/g MLSS less than that at 0.413 g/(g x d). No significant relevance was observed between PHB and BOD5 removal. The PHB of microorganism synthesizes was increased with the increase of temperature. Compared with the lowest temperature (17.1 degrees C), 20% of the total PHB content was increased at the maximum temperature (33.2 degrees C) in active sludge.

[Clinical study of Twin-wires on anchorage on canine retraction].

PURPOSE: The purpose of the study was to evaluate the effects of anchorage by Twin-wires on canine retraction. METHODS: A sample of 15 patients with severe anterior crowding was selected (6 males, 9 females, age average: 13.7 years). All patients underwent removal of the four first premolars during orthodontic treatment. Retraction of canine was achieved by using 0.018 stainless steel wire and NiTi wire. Anchorage reinforcement as a result of this movement was evaluated. The length and width of the dental arch models were measured. Self-control t test was used for data analysis. RESULTS: The length and width of the dental arches, the canine and molar relationships remained unchanged after orthodontic treatment. CONCLUSION: Application of Twin-wires leads to canine retraction and sufficient anchorage consolidation.

[Analysis of the causes and emergency management of 154 traumatized permanent incisors in primary school children].

PURPOSE: This study was designed to investigate the related factors of permanent incisors trauma among primary school children, and evaluate the results of replantation of 56 avulsed teeth. METHODS: Data were collected by 122 questionnaire from teachers or parents of the primary school children with dental trauma, with regard to the related trauma causes, altitudes and emergency management of dental avulsion. 56 avulsed teeth were replanted immediately after appropriate manipulation. The results of replantation were evaluated 1 year later. RESULTS: Tumble (fall off) was the main cause for dental trauma. The maxillary central incisor was most vulnerable to injury, without differences between the right and the left side. Single tooth injury was predominant in all age groups. Children with an incisal overjet tended to have a greater chance of dental trauma. Crown fractures represented 89 (57.79%)of 154 traumatized teeth; root fractures represented 9 (5.84%); avulsed represented 56 (36.3%). Most teachers and parents had little knowledge of the correct procedures for replanting or transporting avulsed teeth. 53 of 56 replanted teeth (94.64%) were integrated successfully. CONCLUSION: The parents and school educators should be advised about prevention of injuries and actions to be taken in case of an accident. The functional and esthetical outcome of replantation in avulsed teeth is excellent.

Precision pore structure optimization of additive manufacturing porous tantalum scaffolds for bone regeneration: A proof-of-concept study.

Currently, the treatment of bone defects in arthroplasty is a challenge in clinical practice. Nonetheless, commercially available orthopaedic scaffolds have shown limited therapeutic effects for large bone defects, especially for massiveand irregular defects. Additively manufactured porous tantalum, in particular, has emerged as a promising material for such scaffolds and is widely used in orthopaedics for its exceptional biocompatibility, osteoinduction, and mechanical properties. Porous tantalum has also exhibited unique advantages in personalised rapid manufacturing, which allows for the creation of customised scaffolds with complex geometric shapes for clinical applications at a low cost and high efficiency. However, studies on the effect of the pore structure of additively manufactured porous tantalum on bone regeneration have been rare. In this study, our group designed and fabricated a batch of precision porous tantalum scaffolds via laser powder bed fusion (LPBF) with pore sizes of 250 µm (Ta 250), 450 µm (Ta 450), 650 µm (Ta 650), and 850 µm (Ta 850). We then performed a series of in vitro experiments and observed that all four groups showed good biocompatibility. In particular, Ta 450 demonstrated the best osteogenic performance. Afterwards, our team used a rat bone defect model to determine the in vivo osteogenic effects. Based on micro-computed tomography and histology, we identified that Ta 450 exhibited the best bone ingrowth performance. Subsequently, sheep femur and hip defect models were used to further confirm the osteogenic effects of Ta 450 scaffolds. Finally, we verified the aforementioned in vitro and in vivo results via clinical application (seven patients waiting for revision total hip arthroplasty) of the Ta 450 scaffold. The clinical results confirmed that Ta 450 had satisfactory clinical outcomes up to the 12-month follow-up. In summary, our findings indicate that 450 µm is the suitable pore size for porous tantalum scaffolds. This study may provide a new therapeutic strategy for the treatment of massive, irreparable, and protracted bone defects in arthroplasty.