Elucidating the negatively influential and potentially toxic mechanism of single and combined micro-sized polyethylene and petroleum to Chlorella vulgaris at the cellular and molecular levels.

Although microplastics (MPs; <5 mm) may interact with co-contaminants (e.g., petroleum) in marine aquatic systems, little is known about their combined toxicity. Therefore, this study explored the toxicities and their mechanisms of micro-sized polyethylene (mPE) and their combination with petroleum to Chlorella vulgaris. The single MPs at various particle sizes, concentrations, and aging degree, single petroleum, and their combinations, were found to pose toxicities to C. vulgaris. This study also found the microcosm's microbial diversity changed. The microbial communities in the C. vulgaris biotopes were altered under exposure to mPE and petroleum, and were disturbed by external factors such as MPs particle size, concentration, aging time, and the combination with petroleum. Furthermore, as compared with the toxicity of petroleum on microalgal transcriptional function, mPE caused less toxic to C. vulgaris, and only impact the posttranslational modification, protein turnover, and signal transduction processes. Most importantly, mPE reduced petroleum toxicity in C. vulgaris via regulating the ABC transporter, eukaryotic ribosome synthesis, and the citrate cycle metabolic pathways. Overall, our findings could fundamentally provide insights into the joint ecotoxicological effects of MPs and petroleum, and highlight the potential risks of co-exsiting pollutants.

Preparation of porous magnetic molecularly imprinted polymers for fast and specifically extracting trace norfloxacin residue in pork liver.

Here, magnetic molecularly imprinted polymers were designed for norfloxacin via oil-in-water emulsifier-free emulsion method. It was prepared by simply mixing norfloxacin, methacrylic acid-co-ethylene glycol dimethacrylate copolymer, and Fe3 O4 together at room temperature. Characterized by multiple analytical tools, the particle size, pore size, pore volume, specific surface area, and saturation magnetization of the product were about 30 µm, 10-500 nm, 2.92 mL/g, 105.84 m2 /g, and 3.052 emu/g, respectively. And the adsorption capacity was high at 27.04 mg/g towards norfloxacin. Combined with ultra high performance liquid chromatography, it was used to determine norfloxacin in real samples. Average recoveries were above 77.44% with relative standard deviations between 1.21 and 6.85% at three spiked levels (n = 3) for lake water and pork liver. The determination was achieved for the most complex biosample pork liver spiked with norfloxacin low to 30 ng/g, about 100 times less than the maximum residue limit regulated by Commission of the European Communities. All evidences demonstrated that the magnetic molecularly imprinted polymers can be used in practice for monitoring norfloxacin either in environmental water or meat product with high accuracy and reliability.

Application of the polystyrene model made by 3-D printing rapid prototyping technology for operation planning in revision lumbar discectomy.

OBJECTIVE: The objective was to evaluate the effectiveness of 3-D rapid prototyping technology in revision lumbar discectomy. 3-D rapid prototyping technology has not been reported in the treatment of revision lumbar discectomy. METHODS: Patients with recurrent lumbar disc herniation who were preparing to undergo revision lumbar discectomy from a single center between January 2011 and 2013 were included in this analysis. Patients were divided into two groups. In group A, 3-D printing technology was used to create subject-specific lumbar vertebral models in the preoperative planning process. Group B underwent lumbar revision as usual. Preoperative and postoperative clinical outcomes were compared between groups included operation time, perioperative blood loss, postoperative complications, Oswestry Disability Index (ODI), Japan Orthopaedics Association (JOA) scores, and visual analogue scale (VAS) scores for back pain and leg pain. RESULTS: A total of 37 patients were included in this study (Group A = 15, Group B = 22). Group A had a significantly shorter operation time (106.53 ± 11.91 vs. 131.92 ± 10.81 min, P < 0.001) and significantly less blood loss (341.67 ± 49.45 vs. 466.77 ± 71.46 ml, P < 0.001). There was no difference between groups for complication rate. There were also no differences between groups for any clinical metric. CONCLUSION: Using the 3-D printing technology before revision lumbar discectomy may reduce the operation time and the perioperative blood loss. There does not appear to be a benefit to using the technology with respect to clinical outcomes. Future prospective studies are needed to further elucidate the efficacy of this emerging technology.

Polyelectrolyte-stabilized graphene oxide liquid crystals against salt, pH, and serum.

Stabilization of colloids is of great significance in nanoscience for their fundamental research and practical applications. Electrostatic repulsion-stabilized anisotropic colloids, such as graphene oxide (GO), can form stable liquid crystals (LCs). However, the electrostatic field would be screened by ions. To stabilize colloidal LCs against electrolyte is an unsolved challenge. Here, an effective strategy is proposed to stabilize GO LCs under harsh conditions by association of polyelectrolytes onto GO sheets. Using sodium poly(styrene sulfonate) (PSS) and poly[2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (PMEDSAH), a kind of polyzwitterion, GO LCs were well-maintained in the presence of NaCl (from 0 M to saturated), extreme pH (from 1 to 13), and serum. Moreover, PSS- or PMEDSAH-coated chemically reduced GO (rGO) also showed stability against electrolyte.

Atmospheric deposition of microplastics at a western China metropolis: Relationship with underlying surface types and human exposure.

The issue of atmospheric microplastic (AMP) contamination is gaining increasing attention, yet the influencing factors and human exposure are not well-understood. In this study, atmospheric depositions were collected in the megacity of Chengdu, China, to investigate the pollution status and spatial disparities in AMP distribution. The relationship between AMP abundance and underlying surface types was then analyzed with the aid of back trajectory simulation. Additionally, a probabilistic estimation of human exposure to AMP deposition during outdoor picnics was provided, followed by the calculation of AMP loading into rivers. Results revealed that the mean deposition flux ranged within 207.1-364.0 N/m2/d (14.17-33.75 µg/m2/d), with significantly larger AMP abundance and sizes in urban compared to rural areas. Areas of compact buildings played an important role in contributing to both fibrous and non-fibrous AMP contamination from urban to rural areas, providing new insight into potential sources of pollution. This suggests that appropriate plastic waste disposal in compact building areas should be prioritized for controlling AMP pollution. Besides, the median ingestion of deposited AMPs during a single picnic was 34.9 N/capita/hour (3.03 × 10-3 µg/capita/hour) for urban areas and 17.8 N/capita/hour (7.74 × 10-4 µg/capita/hour) for suburbs. Furthermore, the worst-case scenario of AMPs loading into rivers was investigated, which could reach 170.7 kg in summertime Chengdu. This work could contribute to a better understanding of the status of AMP pollution and its sources, as well as the potential human exposure risk.

Dialysis-functionalized microfluidic platform for in situ formation of purified liposomes.

Continuous-flow microfluidic devices have been extensively used for producing liposomes due to their high controllability and efficient synthesis processes. However, traditional methods for liposome purification, such as dialysis, gel chromatography, and ultrafiltration, are incompatible with microfluidic devices, which would dramatically restrict the efficiency of liposome synthesis. In this study, we developed a dialysis-functionalized microfluidic platform (DFMP) for in situ formation of purified drug-loaded liposomes. The device was successfully fabricated by using a high-resolution projection micro stereolithography (PµSL) 3D printer. The integrated DFMP consists of a microfluidic mixing unit, a microfluidic dialysis unit, and a dialysis membrane, enabling the liposome preparation and purification in one device. The purified ICG-loaded liposomes prepared by DFMP had a smaller size (264.01±5.34 nm to 173.93±10.71 nm) and a higher encapsulation efficiency (EE) (43.53±0.07% to 46.07±0.67%). In vivo photoacoustic (PA) imaging experiment demonstrated that ICG-loaded liposomes purified with microfluidic dialysis exhibited a stronger penetration and accumulation (2-3 folds) in tumor sites. This work provides a new strategy for one-step production of purified drug-loaded liposomes.

Battery-free optoelectronic patch for photodynamic and light therapies in treating bacteria-infected wounds.

Light therapy is an effective approach for the treatment of a variety of challenging dermatological conditions. In contrast to existing methods involving high doses and large areas of illumination, alternative strategies based on wearable designs that utilize a low light dose over an extended period provide a precise and convenient treatment. In this study, we present a battery-free, skin-integrated optoelectronic patch that incorporates a coil-powered circuit, an array of microscale violet and red light emitting diodes (LEDs), and polymer microneedles (MNs) loaded with 5-aminolevulinic acid (5-ALA). These polymer MNs, based on the biodegradable composite materials of polyvinyl alcohol (PVA) and hyaluronic acid (HA), serve as light waveguides for optical access and a medium for drug release into deeper skin layers. Unlike conventional clinical photomedical appliances with a rigid and fixed light source, this flexible design allows for a conformable light source that can be applied directly to the skin. In animal models with bacterial-infected wounds, the experimental group with the combination treatment of metronomic photodynamic and light therapies reduced 2.48 log10 CFU mL-1 in bactericidal level compared to the control group, indicating an effective anti-infective response. Furthermore, post-treatment analysis revealed the activation of proregenerative genes in monocyte and macrophage cell populations, suggesting enhanced tissue regeneration, neovascularization, and dermal recovery. Overall, this optoelectronic patch design broadens the scope for targeting deep skin lesions, and provides an alternative with the functionality of standard clinical light therapy methods.

[Study on ultrasonic extraction and macroporous resin purification techniques of total flavones from Sedum lineare].

OBJECTIVE: To optimize the ultrasonic extraction condition and purification process of total flavonoids in Sedum lineare by macroporous resin. METHODS: Optimum ultrasonic extraction conditions (ethanol concentration, solid/liquid, ultrasonic time, working temperature) were obtained through orthogonal design. The adsorption ratio and eluting ratio of total flavones were selected as indexes. RESULTS: The optimum ultrasonic extraction condition was 80% ethanol, solid/liquid 1:40, ultrasonic 20 min at 30 degrees C. The adsorbed AB-8 macroporous resin column was eluted by 80% ethanol at the eluting velocity of 2 mL/min, the eluting ratio and purity of total flavones was 94.72% and 43.51%, respectively. CONCLUSION: The method is simple and low cost.

Impacts of microplastic-petroleum pollution on nutrient uptake, growth, and antioxidative activity of Chlorella vulgaris.

As one of the emerging pollutants, microplastics (MPs; <5 mm) can interact with co-contaminants such as petroleum in marine aquatic systems, and their combined toxicity has not been fully investigated. Therefore, this study focused on pollutants such as micro-sized polyethylene (mPE) and petroleum, aiming to explore their single and combined toxicities to microalga Chlorella vulgaris in terms of the cell growth, antioxidative enzymes, and nutrients utilization. The results showed that the MPs alone (particle sizes (i.e., 13, 165, 550 µm), concentrations (i.e., 0.01, 0.1, and 1 g/L), and aging degrees (i.e., aged for 0 d and 90 d under UVA)), and petroleum alone (5% water accommodated fraction, WAF), and their combinations (i.e., 5% WAF + 165 µm-0.1 g/L-aged 0 d mPE, 5% WAF + 165 µm-0.1 g/L-aged 90 d mPE) all posed toxicities risk to C. vulgaris, following an increase in oxidative stress. The cellular utilization of elements such as Fe, Si, Ca, and Mg was inhibited, whereas the uptake of Mn, NO3--N, and PO43--P increased as compared to the control experiments. Furthermore, the relationship between nutrients and growth indicators was analyzed using a structural equation model. The results indicated that Fe and Mn directly affected the indirect NO3--N absorption by C. vulgaris, which indirectly affected the dry cell weight (DCW) of the microalgae. The path coefficient of Fe and Mn affecting nitrate was 0.399 and 0.388, respectively. The absorption of N was the key step for C. vulgaris resist stress. This study provides a novel analysis of the effects of MPs on the growth of microalgae from the perspective of nutrient elements, thereby providing a useful basis for further exploration of the associated mechanisms.

Validation of the Self-Rating of Biological Rhythm Disorder for Adolescents (SBRDA) Scale by Dim Light Melatonin Onset in Healthy Young Adults.

Understanding the biological rhythms that influence young adult health is vital because the combination of biological changes and a circadian phase delay lead to young adults being at high risk of circadian misalignment. We have previously established a self-rating of biological rhythm disorder for adolescents (SBRDA). However, we did not externally validate the SBRDA against objective measures of biological rhythms such as dim light melatonin onset (DLMO)-the gold standard of the endogenous circadian phase. The purpose of this study was to verify the effectiveness of SBRDA in identifying individuals with biological rhythm disorders. Our participants were 42 (47.2%) boys and 47 (52.8%) girls with an average age of 18.5 ± 1.2 years. Saliva samples were collected from 4 h before bed time to 2 h after sleep every 60 min in a dim-light (<50 lx) laboratory environment. Biological rhythm parameters were assessed using questionnaires, including SBRDA, MEQ, and MCTQ. The mean DLMO time (h) was 22.2 ± 1.9. The DLMO correlated significantly with the SBRDA score (r = 0.33, p < 0.001), MEQ score (r = -0.24, p < 0.05), and MSFsc (r = 0.26, p < 0.05). ROC curve analysis showed that SBRDA was of diagnostic value for biological rhythm disorder (p < 0.05). Our observations demonstrate that SBRDA, which is consistent with MEQ and MCTQ, can be used to reflect endogenous circadian rhythm disorders in young adults. Exposure to dim light may activate melatonin secretion and lead to an earlier peak in young adults with biological rhythm disorder.

[Preparation of molecularly imprinted polymers based on covalent organic frameworks and their application to selective recognition of trace norfloxacin in milk].

Norfloxacin (NFX) is an antibiotic that is widely used in animal husbandry. However, the presence of NFX even in trace amounts in animal-derived food may harm human health. Therefore, it is of practical significance to establish a method for monitoring NFX residues in food. Molecularly imprinted polymers (MIPs) imitate interactions established by natural receptors to selectively retain a target molecule, like antibodies or antigens do. MIPs have been widely employed in the selective recognition of specific target molecules from complex samples. Covalent organic frameworks (COFs) are a new type of organic polymer with uniform and ordered crystal structures. COFs form crystal structures by constructing organic units for ordered assembly through reversible chemical reactions. Their porous structure, regular morphology, and easy modification make COFs promising for use as excellent adsorbent carriers. Owing to these advantages of COFs, researchers have attempted to coat one MIP layer on COFs; however, the preparation methods are time-consuming and laborious, and the conditions are harsh. Hence, this study proposes a simple and rapid method for the preparation of novel MIPs with COFs as the support (DP-COF@MIPs) for the selective recognition of NFX. First, a Schiff-base COF (DP-COF) was rapidly synthesized using 3,3'-diaminobenzidine and p-phthalaldehyde with a metal trifluorate as a catalyst at room temperature. Subsequently, a two-step sequence was adopted as the synthesis strategy using NFX as the template, methacrylic acid as a functional monomer, and ethylene glycol dimethacrylate as a crosslinking agent. The entire synthesis was completed within 5 h under mild conditions. The material was then characterized by multiple analytical methods, including field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and the Brunauer-Emmett-Teller (BET) method (to determine the specific surface area). The experimental results confirmed the successful preparation of DP-COF@MIPs. The DP-COF@MIPs presented a rough and porous surface, with a pore size of approximately 17.79 nm (mesoporous structure). The properties of the material were evaluated by adsorption and regeneration experiments. The kinetic adsorption experiment showed that the DP-COF@MIPs reached adsorption equilibrium in 90 min. Two straight lines were fitted using the pseudo-second-order kinetics model based on the experimental results for thermodynamic adsorption, indicating that the adsorption process was primarily dominated by chemical adsorption. The maximum apparent adsorption capacity was 41.57 mg/g. In the selective and competitive binding test, five drugs, namely ciprofloxacin, dimetridazole, oxytetracycline, sulfadiazine, and chloramphenicol, were selected as the interferents. The experimental results showed that the DP-COF@MIPs possessed good stereoselectivity and competitive recognition ability. The regeneration of DP-COF@MIPs was evaluated by multiple cycles of adsorption-desorption experiments. The loss in the adsorption capacity of the particles was only approximately 4.7% after seven adsorption-desorption cycles. These results from the regeneration experiments show that the DP-COF@MIPs had high stability and reusability in the selective adsorption and separation of NFX. In addition, the employed method could accurately identify trace NFX in milk samples. The average recoveries were in the range of 88.8%-92.9% at three spiked levels (0.03, 0.10, and 0.30 mg/L) with relative standard deviations (RSDs) in the range of 0.6-1.7% (n=3). Notably, the method could successfully determine NFX at contents as low as 0.0020 mg/L in the milk sample with an average recovery of 77.6% and RSD of 6.4% (n=3). This concentration is one-fiftieth of the maximum residue level stipulated by the European Union (EU), and even lower than the limit of detection (LOD) of conventional high performance liquid chromatography (HPLC) methods. The above results confirm that DP-COF@MIPs can be used to determine trace NFX in actual complex samples using HPLC equipment, even when coupled to conventional UV-Vis detectors. This study offers a facile and general method for the preparation of MIPs based on COFs with selective recognition ability.

Copper mediated molecularly imprinted polymers for fast recognizing tylosin.

As one kind of artificial antibody, molecularly imprinted polymers (MIPs) has been widely used to separate/enrich target molecules from samples with the complex matrix prior to instrumental analysis. In this work, one novel copper mediated magnetic MIPs was developed towards anti-bacteria macrolide antibiotic tylosin (TYL). The obtained microspheres had a lot of convexities distributed evenly on the surface. And it exhibited high hydrophilicity and superparamagnetic ability, as well as excellent selectivity and specificity. Notably, it only took 5 min to reach the absorption equilibrium for TYL, which made it highly feasible for high-throughput analysis. Furthermore, the microspheres was applied as the magnetic dispersed solid phase extraction material to enrich trace TYL residue in (spiked) human urine. At three spiking levels, mean recoveries are in the range of 76.42-93.72% with relative standard deviations of 2.75-8.24% (n = 3) with HPLC/UV-Vis. The work provided one promising reference to prepare novel solid phase extraction materials for enriching/separating trace component in complex matrix.

Comparison between two pedicle screw augmentation instrumentations in adult degenerative scoliosis with osteoporosis.

BACKGROUND: The operative treatment of adult degenerative scoliosis combined with osteoporosis increase following the epidemiological development. Studies have confirmed that screws in osteoporotic spines have significant lower-screw strength with more frequent screw movements within the vertebra than normal spines. Screws augmented with polymethylmethacrylate (PMMA) or with autogenous bone can offer more powerful corrective force and significant advantages. METHODS: A retrospective analysis was conducted on 31 consecutive patients with degenerative lumbar scoliosis combined with osteoporosis who had surgery from December 2000. All had a minimum of 2-year follow-up. All patients had posterior approach surgery. 14 of them were fixed with pedicle screw by augmentation with polymethylmethacrylate (PMMA) and the other 17 patients with autogenous bone. Age, sex and whether smoking were similar between the two groups. Surgical time, blood loss, blood transfusion, medical cost, post surgery ICU time, hospital day, length of oral pain medicines taken, Pre-and postoperative Oswestry disability index questionnaire and surgical revision were documented and compared. Preoperative, postoperative and final follow up Cobb angle, sagittal lumbar curve, correction rate, and Follow up Cobb loss were also compared. RESULTS: No significant differences were found between the autogenous bone group and polymethylmethacrylate group with regards to all the targets above except for length of oral pain medicines taken and surgery cost. 2 patients were seen leakage during operation, but there is neither damage of nerve nor symptom after operation. No revision was needed. CONCLUSION: Both augmentation pedicle screw with polymethylmethacrylate (PMMA) and autogenous bone treating degenerative lumbar scoliosis combined with osteoporosis can achieve a good surgical result. Less oral pain medicines taken are the potential benefits of polymethylmethacrylate augmentation, but that is at the cost of more medical spending.

Three-dimensional hydrogel is suitable for targeted investigation of amoeboid migration of glioma cells.

Glioblastoma (GBM) invasion and migration are key biological behaviors leading to refractoriness to current therapies and infiltration into the non­tumor brain parenchyma. GBM cell migration is strongly dependent on tumor architecture in vivo, which is absent in traditional two­dimensional (2D) monolayer culture. The present study applied a three­dimensional (3D) hydrogel model to rebuild the tumor architecture in vitro. Treatment with NSC23766, a specific inhibitor of Ras­related C3 botulinum toxin substrate 1 (Rac1), inhibited the mesenchymal invasiveness however triggered the amoeboid motility called mesenchymal­amoeboid transition (MAT). Notably, NSC23766 stimulated U87 GBM cell migration in the 3D hydrogel. However, this compound inhibited cell motility in 2D monolayer culture without tumor architecture for MAT, suggesting the advantage of 3D hydrogel to investigate tumor cell invasion. Due to the inverse interaction of Rac1 and Ras homolog family member A (RhoA) signaling in the transition between mesenchymal and amoeboid morphology, simultaneous treatment of NSC23766 and Y27632 (selective Rho associated coiled­coil containing protein kinase 1 inhibitor), abolished U87 GBM cell migration through inhibiting MAT and amoeboid­mesenchymal transition. In addition, Y27632 induced integrin expression which gave rise to the focal adhesion to facilitate the mesenchymal invasion. The results of the present study demonstrated that the 3D hydrogel was a preferable model in vitro to study tumor cell invasion and migration. The combined inhibition of Rac1 and RhoA signaling would be a promising strategy to suppress GBM invasion.

Near-infrared rechargeable "optical battery" implant for irradiation-free photodynamic therapy.

As a minimal or noninvasive therapeutic method for tumors, photodynamic therapy (PDT) induced by the external laser irradiations has attracted great attentions. However, the UV-visible responsive property with low tissue penetration and photothermal effect from the prolonged irradiation impedes their further applications. Herein, a near-infrared (NIR) rechargeable "optical battery" for irradiation-free PDT is fabricated by embedding upconversion materials, persistent luminescence materials, photosensitizer into biocompatible polydimethylsiloxane. After 5 s quickly charged by 980-nm NIR laser, the PDT "optical battery" can generate green persistent luminescence and produce cytotoxic singlet oxygen for continuous irradiation-free PDT (∼30 min) without external irradiation. Due to deep tissue penetration and discontinuous short exposure of NIR light charging source, the "optical battery" can still be charged to continuously generate singlet oxygen in deep tissue (∼4 mm) with low photothermal effect. The PDT implant can be easily optimized in size and shape aiming at different nidus sites and achieved different functions by adding other functional components (e.g. CaO2 for oxygen envolving to overcome hypoxia tumor). The effective tumor proliferation inhibiting capability of this NIR rechargeable "optical battery" may give rise to next generation of intelligent stimuli-responsive nanomedicine and noninvasive photo bio-stimulation research for future clinical applications.

Application of a Shape-Memory Alloy Concentrator in Displaced Patella Fractures: Technique and Long-Term Results.

Operative treatment is usually recommended in displaced patella fractures. Several techniques have been advocated for internal fixation of patella fractures. Despite the relatively good clinical outcomes that have been demonstrated in many studies, postoperative morbidities such as fixation failure, nonunion, infection, and knee stiffness are not uncommon. We present a new alternative treatment technique for displaced patellar fractures. Between April 1995 and May 2005, we used the Nitinol Patella Concentrator (NTPC) to treat 156 consecutive patients with displaced patellar fractures. Injuries arose from vehicular accidents in 56 (35.9%) cases, direct falls onto the knee in 85 (54.5%) cases, and sports injuries in 15 (9.6%) cases. The mean patient age was 46.3 years (range, 25-77 years). Clinical assessments were made using the Böstman knee score and the MOS SF-36 questionnaire (Medical Outcomes Study 36-item short-form health survey), which were both recorded at the final follow-up visit. The mean follow-up was 7.3 years (range, 6-17 years). At the final follow-up, the Böstman knee scores were excellent in 88 cases (28-30), good in 55 (20-27), and unsatisfactory in 13 (<20). According to the MOS SF-36 evaluation, the average score was 84.5 (range, 62-91). Treatment of patellar fracture with the NTPC not only may serve as an effective and rigid fixation method in multifragmented displaced and inferior pole fractures, but also may provide continuous concentrative compression during the osseous healing process. Thus, use of the NTPC may help restore the functional integrity of the extensor mechanism and permit early rehabilitation with a lower incidence of postoperative complications.

Comparative study of comminuted posterior acetabular wall fracture treated with the Acetabular Tridimensional Memory Fixation System.

BACKGROUND: Posterior wall fractures are one of the most common acetabular fractures. However, only 30% of these fractures involve a single large fragment, and comminuted acetabular posterior wall fractures pose a particular surgical challenge. The purpose of this study was to compare outcomes between patients who received fixation for comminuted posterior wall fracture using the Acetabular Tridimensional Memory Fixation System (ATMFS) and patients who underwent fixation with conventional screws and buttress plates (Plates group). METHOD: Between April 2003 and May 2007, 196 consecutive patients who sustained a comminuted posterior wall fracture of acetabulum were treated with ATMFS or conventional screws and buttress plates. Operative time, fluoroscopy time, blood loss, and any intra-operative complications were recorded. Plain AP and lateral radiographs were obtained at all visits (Matta's criteria). Modified Merle d' Aubigne-Postel score, and Mos SF-36 score were compared between groups. RESULTS: Fifty patients were included in the analysis with 26 in the ATMFS group and 24 in the Plates group. The mean follow-up time was 57.5 months, ranging from 31 to 69 months. All patients had fully healed fractures at the final follow-up. There was no difference in clinical outcomes or radiological evaluations between groups. CONCLUSION: Patients with comminuted posterior wall fractures of the acetabulum treated with the ATMFS or conventional screws and buttress plate techniques achieve a good surgical result. Both techniques are safe, reliable, and practical. Use of the ATMFS technique may reduce blood loss and improve rigid support to marginal bone impaction. The use ATMFS may need additional support when fractures involve the superior roof.

Enhanced bone tissue regeneration by antibacterial and osteoinductive silica-HACC-zein composite scaffolds loaded with rhBMP-2.

Next-generation orthopedic implants with both osteoinductivity and antibacterial ability are greatly needed. In the present study, biodegradable rhBMP-2 loaded zein-based scaffolds with a macroporous structure were synthesized, and SBA-15 nanoparticles and hydroxypropyltrimethyl ammonium chloride chitosan (HACC) were incorporated into the scaffolds to produce an anti-infective composite scaffold for delivery of osteogenic factors that facilitate the functional repair of bone defects. The silica/HACC/zein scaffolds developed here showed bioactivity, biocompatibility, and effective antibacterial activity. Confocal laser scanning microscopy (CLSM) was used to quantitatively measure the bactericidal efficacy with respect to bacterial adhesion. Results showed that the sample zein-HACC-S20 exhibited long-lasting antibacterial activity against Escherichia coli and Staphylococcus aureus up to 5 d. At a low dosage of rhBMP-2 (ca. 80 µg), the scaffolds released rhBMP-2 protein efficiently at a relatively slow rate, even after 27 d. An ALP activity and ECM mineralization assay showed that the zein-HACC-S20 scaffolds exhibited significant early osteogenic differentiation by generating enhanced ALP product on day 14 and ECM mineralization on day 21. In a mouse model of thigh muscle pouches, zein-S20 and zein-HACC-S20 groups resulted in obvious bone formation and gave more extensive mineralization to the implants than silica free groups, indicating effective bone induction in vivo. In a rabbit model of critical-sized radius bone defects (20 mm in length and 5 mm in diameter), the bone defects were almost fully repaired and bone marrow cavity recanalization was detectable by 3D micro-CT technique and histological analysis after 12 weeks. In this way, the zein-HACC-S20 scaffolds were proven to significantly promote the bone repair. They also demonstrated considerable promise for tissue engineering. Silica/HACC/zein scaffolds with both antibacterial activity and the ability to induce osteogenesis have immense potential in orthopedics and other biomedical applications.

Poly-dipeptides encoded by the C9orf72 repeats bind nucleoli, impede RNA biogenesis, and kill cells.

Many RNA regulatory proteins controlling pre-messenger RNA splicing contain serine:arginine (SR) repeats. Here, we found that these SR domains bound hydrogel droplets composed of fibrous polymers of the low-complexity domain of heterogeneous ribonucleoprotein A2 (hnRNPA2). Hydrogel binding was reversed upon phosphorylation of the SR domain by CDC2-like kinases 1 and 2 (CLK1/2). Mutated variants of the SR domains changing serine to glycine (SR-to-GR variants) also bound to hnRNPA2 hydrogels but were not affected by CLK1/2. When expressed in mammalian cells, these variants bound nucleoli. The translation products of the sense and antisense transcripts of the expansion repeats associated with the C9orf72 gene altered in neurodegenerative disease encode GRn and PRn repeat polypeptides. Both peptides bound to hnRNPA2 hydrogels independent of CLK1/2 activity. When applied to cultured cells, both peptides entered cells, migrated to the nucleus, bound nucleoli, and poisoned RNA biogenesis, which caused cell death.