BACKGROUND:Chitosan is a kind of biomaterial with good hemostatic, antibacterial and absorption properties. The guanidine modified chitosan holding better antibacterial and absorption abilities is a commonly used chemical separation material. However, its coagulation property is still unclear. OBJECTIVE:To evaluate the in vitro hemostatic property and cytotoxicity of the guanidine modified chitosan, and to explore its availability as a hemostatic material.METHODS:The guanidine modified chitosan was synthesized with the raw materials of chitosan and arginine, and the coupling agents of EDC and NHS. The coagulation ability was evaluated preliminarily through the whole blood coagulation time, and three in vitro coagulation indexes (activated partial thromboplastin time, prothrombin time and thrombin time). The guanidine modified chitosan extracts were co-cultured with the mouse fibroblasts, and then the cell growth was observed by MTT assay and fluorescence microscope. RESULTS AND CONCLUSION:The guanidine modified chitosan shortened the whole blood coagulation time, suggesting its hemostatic property. In vitro coagulation results indicated that the guanidine modified chitosan exerted the effect not through the traditional endogenous and extrinsic coagulation pathways. Guanidino group has not been proved to be hemostatic, so the chitosan may be the effective component. MTT assay showed that the cell proliferation rate was 87.8%and the toxicity level was grade 1. Fluorescent staining observed abundant live cells, and few dead cells, indicating that the guanidine modified chitosan exhibits low cytotoxicity.

In this study, we explored the neural mechanism underlying impaired stereopsis and possible functional plasticity after strabismus surgery. We enrolled 18 stereo-deficient patients with intermittent exotropia before and after surgery, along with 18 healthy controls. Functional magnetic resonance imaging data were collected when participants viewed three-dimensional stimuli. Compared with controls, preoperative patients showed hypoactivation in higher-level dorsal (visual and parietal) areas and ventral visual areas. Pre- and postoperative activation did not significantly differ in patients overall; patients with improved stereopsis showed stronger postoperative activation than preoperative activation in the right V3A and left intraparietal sulcus. Worse stereopsis and fusional control were correlated with preoperative hypoactivation, suggesting that cortical deficits along the two streams might reflect impaired stereopsis in intermittent exotropia. The correlation between improved stereopsis and activation in the right V3A after surgery indicates that functional plasticity may underlie the improvement of stereopsis. Thus, additional postoperative strategies are needed to promote functional plasticity and enhance the recovery of stereopsis.
Humans ; Exotropia/surgery* ; Depth Perception/physiology* ; Strabismus/surgery* ; Oculomotor Muscles/surgery*

Aging associated cognitive decline has been linked to dampened neural stem/progenitor cells (NSC/NPCs) activities manifested by decreased proliferation, reduced propensity to produce neurons, and increased differentiation into astrocytes. While gene transcription changes objectively reveal molecular alterations of cells undergoing various biological processes, the search for molecular mechanisms underlying aging of NSC/NPCs has been confronted by the enormous heterogeneity in cellular compositions of the brain and the complex cellular microenvironment where NSC/NPCs reside. Moreover, brain NSC/NPCs themselves are not a homogenous population, making it even more difficult to uncover NSC/NPC sub-type specific aging mechanisms. Here, using both population-based and single cell transcriptome analyses of young and aged mouse forebrain ependymal and subependymal regions and comprehensive "big-data" processing, we report that NSC/NPCs reside in a rather inflammatory environment in aged brain, which likely contributes to the differentiation bias towards astrocytes versus neurons. Moreover, single cell transcriptome analyses revealed that different aged NSC/NPC subpopulations, while all have reduced cell proliferation, use different gene transcription programs to regulate age-dependent decline in cell cycle. Interestingly, changes in cell proliferation capacity are not influenced by inflammatory cytokines, but likely result from cell intrinsic mechanisms. The Erk/Mapk pathway appears to be critically involved in regulating age-dependent changes in the capacity for NSC/NPCs to undergo clonal expansion. Together this study is the first example of using population and single cell based transcriptome analyses to unveil the molecular interplay between different NSC/NPCs and their microenvironment in the context of the aging brain.
Aging ; genetics ; Animals ; Astrocytes ; cytology ; metabolism ; Brain ; cytology ; metabolism ; Cell Differentiation ; genetics ; Cell Division ; genetics ; Cell Proliferation ; genetics ; Gene Expression Regulation ; genetics ; Mice ; Neural Stem Cells ; metabolism ; Single-Cell Analysis ; Stem Cells ; cytology ; metabolism ; Transcriptome ; genetics

The mammalian brain is heterogeneous, containing billions of neurons and trillions of synapses forming various neural circuitries, through which sense, movement, thought, and emotion arise. The cellular heterogeneity of the brain has made it difficult to study the molecular logic of neural circuitry wiring, pruning, activation, and plasticity, until recently, transcriptome analyses with single cell resolution makes decoding of gene regulatory networks underlying aforementioned circuitry properties possible. Here we report success in performing both electrophysiological and whole-genome transcriptome analyses on single human neurons in culture. Using Weighted Gene Coexpression Network Analyses (WGCNA), we identified gene clusters highly correlated with neuronal maturation judged by electrophysiological characteristics. A tight link between neuronal maturation and genes involved in ubiquitination and mitochondrial function was revealed. Moreover, we identified a list of candidate genes, which could potentially serve as biomarkers for neuronal maturation. Coupled electrophysiological recording and single cell transcriptome analysis will serve as powerful tools in the future to unveil molecular logics for neural circuitry functions.
Antigens, Differentiation ; biosynthesis ; Electrophysiological Phenomena ; physiology ; Gene Expression Regulation ; physiology ; Genome-Wide Association Study ; Human Embryonic Stem Cells ; cytology ; metabolism ; Humans ; Induced Pluripotent Stem Cells ; cytology ; metabolism ; Multigene Family ; physiology ; Neurons ; cytology ; metabolism ; Transcriptome ; physiology