The stabilization of ultrafiltration membrane blended with randomly structured amphiphilic copolymer: Micropollutants adsorption properties in filtration processes.

In this study, a blend membrane consisting of polyvinylidene fluoride (PVDF) and tertiary amine containing random copolymer poly(methyl methacrylate-r-dimethylamino-2-ethyl methacrylate) (P(MMA-r-DMAEMA)) was fabricated and utilized as an adsorptive membrane for micropollutants (anionic dye and heavy metal ions) removal from aqueous solutions. Cross-linking the random copolymer by p-xylylene dichloride (XDC) produced the membrane with improved copolymer retention ratio and stability, while slightly variated physicochemical properties. Besides, the fluxes of crosslinked blend membranes dramatically increased from 0.7 ± 0.1 L/(m2h) to 118.6 ± 5.9 L/(m2h). Then the present blend membrane was carried out adsorption and filtration experiments to investigate the influence of various of operation parameters including initial solution pH value, contacting time, initial solution concentration, and recycling efficiency on micropollutants removal. The experimental results showed that the removal of the anionic dyes and heavy metal ions on this tertiary amine containing blend membrane was a pH-dependent process with the maximum adsorption capacity at the initial solution pH of 3.5 for anionic dyes and 6.0 for metal ions, respectively. The membrane showed highly efficient capture of sunset yellow (above 99%). Meanwhile, the captured sunset yellow was recovered and concentrated with a small volume of alkaline solutions at pH 10.0, which simultaneously regenerated the membrane for its reuse. In a 3-cycle capture-recovery test, the membrane demonstrated a high sunset yellow recovery ratio and a volumetric concentration ratio as high as 400%. Our study provides an alternative strategy for functionalized membrane fabrication, micropollutants removal and recovery.

Benign esophageal schwannoma: A case report and brief overview.

RATIONALE: Schwannoma is a tumor of the peripheral nervous system that originated in the Schwann cells of the neural sheath. Esophageal schwannomas are rare esophageal submucosal tumors, comprising approximately 2% of esophageal tumors. Since the symptoms, signs, and images of esophageal schwannoma are not specific, its preoperative diagnosis remains challenging. PATIENT CONCERNS: A 67-year-old woman visited our department with complaints of gradually developed dysphagia and dyspnea for 4 years. A chest computed tomography scan showed a well-demarcated, enhancing homogeneous tumor measuring 61 × 46 × 60 mm in the upper third of the esophagus. Upper gastrointestinal endoscopy revealed a smooth elevated lesion located 19 to 24 cm from the incisor teeth. An endoscopic ultrasound-guided fine-needle aspiration demonstrated the presence of benign spindle cells. DIAGNOSES: Histopathologic examination revealed spindle-shaped cells in a fasciculated and disarrayed architecture. The immunohistochemical study showed positivity for S-100 protein antibody and absence of staining for CD117, CD34, smooth muscle actin, and Desmin. These findings confirmed the diagnosis of benign esophageal schwannoma. INTERVENTIONS: The tumor was considered to be difficult to repair the esophagus by direct anastomosis after tumor resection. Therefore, subtotal esophagectomy and esophagogastrostomy in the right thorax were performed. OUTCOMES: The patient has been doing well with no recurrence at 36 months after the operation. LESSONS: The symptoms and surgical procedures for benign esophageal schwannoma depend on the size and location of the tumor, proper and timely treatment is essential. A definitive diagnosis is confirmed by histology, and complete excision should yield good results.

Spatiotemporal delivery of nanoformulated liraglutide for cardiac regeneration after myocardial infarction.

The local, intramyocardial injection of proteins into the infarcted heart is an attractive option to initiate cardiac regeneration after myocardial infarction (MI). Liraglutide, which was developed as a treatment for type 2 diabetes, has been implicated as one of the most promising protein candidates in cardiac regeneration. A significant challenge to the therapeutic use of this protein is its short half-life in vivo. In this study, we evaluated the therapeutic effects and long-term retention of liraglutide loaded in poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG) nanoparticles (NP-liraglutide) on experimental MI. PLGA-PEG nanoparticles (NPs) have been shown to efficiently load liraglutide and release bioactive liraglutide in a sustained manner. For in vitro test, the released liraglutide retained bioactivity, as measured by its ability to activate liraglutide signaling pathways. Next, we compared the effects of an intramyocardial injection of saline, empty NPs, free liraglutide and NP-liraglutide in a rat model of MI. NPs were detected in the myocardium for up to 4 weeks. More importantly, an intramyocardial injection of NP-liraglutide was sufficient to improve cardiac function (P<0.05), attenuate the infarct size (P<0.05), preserve wall thickness (P<0.05), promote angiogenesis (P<0.05) and prevent cardiomyocyte apoptosis (P<0.05) at 4 weeks after injection without affecting glucose levels. The local, controlled, intramyocardial delivery of NP-liraglutide represents an effective and promising strategy for the treatment of MI.

Hybrid small-diameter vascular grafts: Anti-expansion effect of electrospun poly ε-caprolactone on heparin-coated decellularized matrices.

Small-diameter vascular grafts (SDVGs) (D < 6 mm) are increasingly needed in clinical settings for cardiovascular disease, including coronary artery and peripheral vascular pathologies. Vessels made from synthetic polymers have shortcomings such as thrombosis, intimal hyperplasia, calcification, chronic inflammation and no growth potential. Decellularized xenografts are commonly used as a tissue-engineering substitute for vascular reconstructive procedures. Although acellular allogeneic vascular grafts have good histocompatibility and antithrombotic properties, the decellularization process may damage the biomechanics and accelerate the elastin deformation and degradation, finally resulting in vascular graft expansion and even aneurysm formation. Here, to address these problems, we combine synthetic polymers with natural decellularized small-diameter vessels to fabricate hybrid tissue-engineered vascular grafts (HTEV). The donor aortic vessels were decellularized with a combination of different detergents and dehydrated under a vacuum freeze-drying process. Polycaprolactone (PCL) nanofibers were electrospun (ES) outside the acellular aortic vascular grafts to strengthen the decellularized matrix. The intimal surfaces of the hybrid small-diameter vascular grafts were coated with heparin before the allograft transplantation. Histopathology and scanning electron microscope revealed that the media of the decellularized vessels were severely injured. Mechanical testing of scaffolds showed that ES-PCL significantly enhanced the biomechanics of decellularized vessels. Vascular ultrasound and micro-CT angiography showed that all grafts after implantation in a rat model were satisfactorily patent for up to 6 weeks. ES-PCL successfully prevented the occurrence of vasodilation and aneurysm formation after transplantation and reduced the cell inflammatory infiltration. In conclusion, the HTEV with perfect histocompatibility and biomechanics provide a facile and useful technique for the development of SDVGs.

A novel multifunctional biomedical material based on polyacrylonitrile: Preparation and characterization.

Wet spun microfibers have great potential in the design of multifunctional controlled release materials. Curcumin (Cur) and vitamin E acetate (Vit. E Ac) were used as a model drug system to evaluate the potential application of the drug-loaded microfiber system for enhanced delivery. The drugs and polyacrylonitrile (PAN) were blended together and spun to produce the target drug-loaded microfiber using an improved wet-spinning method and then the microfibers were successfully woven into fabrics. Morphological, mechanical properties, thermal behavior, drug release performance characteristics, and cytocompatibility were determined. The drug-loaded microfiber had a lobed "kidney" shape with a height of 50-100 µm and width of 100-200 µm. The addition of Cur and Vit. E Ac had a great influence on the surface and cross section structure of the microfiber, leading to a rough surface having microvoids. X-ray diffraction and Fourier transform infrared spectroscopy indicated that the drugs were successfully encapsulated and dispersed evenly in the microfilament fiber. After drug loading, the mechanical performance of the microfilament changed, with the breaking strength improved slightly, but the tensile elongation increased significantly. Thermogravimetric results showed that the drug load had no apparent adverse effect on the thermal properties of the microfibers. However, drug release from the fiber, as determined through in-vitro experiments, is relatively low and this property is maintained over time. Furthermore, in-vitro cytocompatibility testing showed that no cytotoxicity on the L929 cells was found up to 5% and 10% respectively of the theoretical drug loading content (TDLC) of curcumin and vitamin E acetate. This study provides reference data to aid the development of multifunctional textiles and to explore their use in the biomedical material field.

[Cloning of human amelogenin gene encoding mature peptide].

PURPOSE: The purpose of this study was to clone human amelogenin gene encoding mature protein, which provides a basis for expressing the recombinant human amelogenin in Escherichia coli. in the future. METHODS: In this study, total RNA was extracted from the dental germ of a legally aborted embryo by Trizol. Using RT-PCR technique we obtained synthesis of cDNA from the total RNA, and the desired DNA products were conducted with PCR from cDNA. The segment was inserted into expression vector PQE30 and the interesting plasmid was transformed into Escherichia coli. host DH5alpha. The double-stranded DNA of positive clone was analyzed by PCR, restriction endonuclease mapping and DNA sequence analysis. RESULTS: The sequence analysis of recombinant plasmid showed that the human amelogenin encoding mature protein was inserted into vector PQE30 accurately. CONCLUSIONS: We conducted human amelogenin encoding mature protein from dental germ of a legally aborted embryo and got the recombinant plasmid which may express amelogenin gene for further research.