Poly(ε-caprolactone) (PCL) was conjugated with heparin and fabricated into nonwoven tubular scaffold by electrospinning. The dynamic contact angle analysis revealed the hydrophilicity improvement due to heparin concentrating on the conjugate surface. The microbicinchoninic acid and quartz crystal microbalance measurements implied that the conjugate can significantly reduce the absorption of plasma protein, such as albumin and fibrinogen, indicative of the good blood biocompatibility. As evidenced by Enzyme Linked Immunosorbent Assay, the electrospun conjugate scaffolds possessed a higher loading capability of vascular endothelial growth factor (VEGF) than that of the blank PCL in aqueous solution via static interaction. The viability of loaded VEGF was evaluated by cell culture and adhesion tests. The amount and morphology of cells were substantially improved after VEGF was loaded into scaffolds exhibiting excellent cell biocompatibility. To assess the in vivo biocompatibility, a tubular scaffold (L = 4 cm, D = 2 mm) was transplanted into dog's femoral artery. The scaffold patency was inspected by carotid artery angiography 4 weeks after implantation. The explanted scaffold was also investigated by histological analysis including hematoxyline eosin, Millere Masson (collagen and elastin), and von Kossa (calcium) stain. Furthermore, von Willebrand factor immunohistochemical stain was performed to examine the formation of endothelial layer. The conjugate shows the potential to be used as scaffold materials in vascular tissue engineering.
A biocompatible diisocyanate, lysine ethyl ester diisocyanate, was prepared. Afterwards, biodegradable polyurethane (PU) was synthesized by the stepgrowth polymerization of this diisocyanate with hydroxyl terminated poly(ε-caprolactone) in the presence of 1,4-butanediol as a chain-extender. The resulting PU was characterized by GPC, IR and DSC measurements. Its mechanical strength was found to increase with increasing the hard segment content. The PU microfiber meshes with high porosity were obtained by solution electrospinning technique. Their degradation behavior in the PBS and enzymatic solution was also investigated.
BackgroundBuyang Huanwu Decoction (BYHWD) is a Traditional Chinese Medicine (TCM) formula for treating stroke-induced disability. Xiaoshuan enteric-coated capsule (XSECC), derived from the formula BYHWD, is a drug approved by the China Food and Drug Administration (CFDA) for stroke management. To further investigate the potential protective effects of XSECC on neurovascular functions, we endeavour to monitor the neurovascular functions using multimodal magnetic resonance imaging (MRI) and evaluated histopathological changes of neurovascular unit (NVU) after stroke.MethodsIschemic stroke was induced by permanent middle cerebral artery occlusion (pMCAO). XSECC (420 mg/kg) was orally administered 2 h after stroke and daily thereafter. T2-weighted imaging (T2WI), T2 relaxometry mapping and diffusion tensor imaging (DTI) were used to measure cerebral infarct volume, edema and white matter fiber integrity, respectively. Neurochemical metabolite levels were monitored by 1H-magnetic resonance spectroscopy (1H-MRS). Arterial spin labeling (ASL) – cerebral blood flow (CBF) measurements and structural magnetic resonance angiography (MRA) images provided real-time and dynamic information about vascular hemodynamic dysfunction on the 3rd, 7th and 14th days after pMCAO. At the last imaging time point, immunohistochemistry, immunofluorescence as well as transmission electron microscopy (TEM) were used to test the microscopic and ultrastructural changes of NVU.ResultsT2WI, T2 relaxometry mapping and Fractional anisotropy (FA) in DTI showed that XSECC significantly reduced cerebral infarct volume, relieved edema and alleviated nerve fiber injuries, respectively. 1H-MRS provided information about improvement of neuronal/glial metabolism after XSECC treatment. Moreover, ASL – CBF measurements combined with MRA showed that XSECC significantly increased CBF and vascular signal strength and alleviated ischemia-induced morphological changes of arteries in ischemic hemisphere within 14 days after stroke. In addition, neuron specific nuclear protein (NeuN), glial fibrillary acidic protein (GFAP), CD34 staining and TEM detection indicated that XSECC not only ameliorated neuronal injury, but also reduced endothelial damage and inhibited astrocyte proliferation.ConclusionsOur results suggested that XSECC has multi-target neurovascular protective effects on ischemic stroke, which may be closely correlated with the improvement of cerebral blood supply and neuronal/glial metabolism.
ObjectiveThis current meta-analysis was conducted to evaluate effects of dexmedetomidine on neonatal maternal factors.MethodsThe electronic databases of PubMed, Embase, and Cochrane Central Register of Controlled Trials were searched. The primary outcomes were neonatal parameters, including umbilical blood gases and Apgar scores. The secondary outcomes were maternal parameters.ResultsWe identified six randomized controlled trials (RCTs). No differences in neonatal umbilical blood gases, and Apgar scores at 1 min (WMD: −0.09; 95% CI: −0.21 to 0.04; I2 = 0%) and 5 min (weighted mean difference (WMD): 0.03; 95% CI: −0.05 to 0.11; I2 = 37%) were observed with dexmedetomidine. For maternal parameters, characteristics of motor and sensory block and postoperative analgesia (standard mean difference (SMD): 3.99; 95% CI: 2.85 to 5.12; I2 = 78%) were significantly improved after dexmedetomidine treatment. Adverse events, including nausea/vomiting and shivering (risk ratio (RR): 0.26; 95% CI: 0.11 to 0.60; I2 = 0%), were lower after dexmedetomidine treatment.ConclusionThis meta-analysis shows that dexmedetomidine is safe for neonates who are delivered by caesarean section. Moreover, dexmedetomidine used in neuraxial anaesthesia can improve the characteristics of motor and sensory block and prolong the maternal pain-free period. Dexmedetomidine can also reduce the maternal incidence of postoperative adverse effects.
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