Aim: To study the dexamethasone pharmacokinetics in the inner ear perilymph of guinea pigs using high-pressure liquid chromatography. Methods: Sixty-five guinea pigs were divided into three groups. In the first group, the drug application protocol used an intra-abdominal dose of 0.5% dexamethasone 4 mg·kg–1. In the second group, an intratympanic application dose of 0.5% dexamethasone 150 µl was used. The third group was the control group. The concentrations of dexamethasone in inner ear perilymph were determined by high-pressure liquid chromatography. Results: The perilymph concentration-time curves of dexamethasone conformed to a one-compartment open model after an intra-abdominal application. The Cmax was 0.927 ± 0.008 mg·l–1, the Tmax 1.47 ± 0.04 h, the T1/2K 2.92 ± 0.056 h, the AUC 5.533 ± 0.05 mg·h·l–1, the T1/2Ka 0.47 ± 0.024 h. After an intratympanic application, the perilymph concentration-time curves of dexamethasone also conformed to a one-compartment open model. The Cmax was 0.201 ± 0.006 mg·l–1, the Tmax 0.117 ± 0.06 h, the AUC 0.868 ± 0.004 mg·h·l–1, the T1/2K 2.918 ± 0.089 h, the T1/2Ka 0.161 ± 0.009 h. Compared to the intra-abdominal application, the intratympanic application resulted in similar levels of inner ear perilymph drug concentrations in 30 min. Conclusion: Dexamethasone can penetrate the blood-labyrinthine barrier after intra-abdominal application. Dexamethasone can enter into perilymph after intratympanic application. Under the condition of the study, the intratympanic application resulted in a similar level of inner ear perilymph drug concentrations compared to the intra-abdominal application in 30 min.
Peripheral motor nerve injuries are a significant source of morbidity. Neural stem cells (NSCs), a group of relatively primitive cells, possess self-renewal ability and multidifferentiation potential. NSCs may be successfully separated from the human embryo and central nervous system (CNS) and differentiated into mature neurons and gliacytes by in vitro induction or transplantation into the body and may be differentiated into Schwann-like cells under specific conditions. It has been demonstrated that the ability of peripheral nerves to regenerate is mainly attributable to Schwann cells. NSC transplantation can promote peripheral nerve regeneration and provide a new means for treatment of peripheral nerve injury. In recent years, the study of NSCs has become a focus of many laboratories, but the biological characteristics and differentiation regulation mechanisms are not fully clear. In this article, we provide a brief review of NSC characteristics, cultivation, oriented differentiation, and clinical application.
Abstract. It has been recently reported that side population (SP) cells in nasopharyngeal carcinoma (NPC) cell lines display characteristics of cancer stem-like cells. However, the biological behavior and the significance of these cells for NPC progression remain unclear. In this study, we isolated SP cells from the NPC cell line CNE-2 by flow cytometry and investigated their biological characteristics. We discovered that SP cells had stronger colony forming abilities compared to the non-side population (NSP) cells, and observed that some SP cells looked more like the shape of mesenchymal cells when cultured in the common polyHEMA-coated flask. When checked by quantitative real-time PCR, the SP cells expressed higher levels of stemness-related genes Oct4, Sox2 and Nanog, and mesenchymal cell-related genes N-cadherin, vimentin and Snail, while they expressed lower levels of the epithelial cell-related gene, E-cadherin. Western blot and immunofluorescence staining methods further verified that SP cells expressed higher vimentin and expressed lower E-cadherin levels. Finally, Transwell invasion assay results indicated that the SP cells had higher invasive potential compared to NSP cells. Collectively, our data reveal that SP cells in the CNE-2 cell line not only possess the properties of cancer stem cells, but also have more mesenchymal cell characteristics which are associated with epithelial mesenchymal transition (EMT) and cancer cell invasion and metastasis. These findings are helpful for developing novel targets for effective clinical treatment of NPC.
The IMAP-supercharged cervicothoracic flap technique offers a reliable method for massive face and neck reconstruction. We recommended that the IMAP should always be preserved in the flap as a saving option for potential flap congestion or arterial insufficiency.
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