ABSTRACT
A survey of human enterovirus (HEV) infections from 2004 to 2008 was conducted in Yokohama City, Japan. A total of 260 clinical samples in 247 patients were shown to be positive for enterovirus. Among them, 25 serotypes were identified, including 3 serotypes of poliovirus (19 samples). The prevalence rates of hand-foot-and-mouth disease (HFMD), herpangina, and respiratory illness associated with nonpolio HEV infections were also analyzed. Seven serotypes were highly associated with HFMD or herpangina. These 7 virus serotypes were prevalent during summer and autumn with a peak in July, and were prevalent in children under 6 years old with a peak from 1 to 2 years old. HEV-related diseases were not limited to HFMD and herpangina but also included respiratory illnesses, such as the common cold. The results of this study suggested the importance of periodic surveys to monitor severe diseases caused by HEVs.
Subject(s)
Enterovirus Infections/epidemiology , Enterovirus/classification , Enterovirus/isolation & purification , Age Factors , Child, Preschool , Female , Humans , Infant , Japan/epidemiology , Male , Prevalence , Seasons , SerotypingABSTRACT
Neural stem cells differentiate from embryonic stem cells via formation of neural stem spheres under free-floating conditions in astrocyte-conditioned medium. Subsequent culture of neural stem spheres on an adhesive substrate with fibroblast growth factor-2 promotes the migration of neural stem cells onto the substrate, resulting in an increase in the number of cells. These embryonic stem cell-derived neural stem cells can be differentiated almost exclusively into astrocytes by withdrawing fibroblast growth factor-2 from the medium without any additional instructions.
Subject(s)
Astrocytes/chemistry , Cell Differentiation/physiology , Neurons/physiology , Stem Cells/physiology , Animals , Astrocytes/physiology , Cell Count , Cell Differentiation/drug effects , Cell Movement/drug effects , Cell Movement/physiology , Cells, Cultured , Culture Media, Conditioned/pharmacology , Embryo, Mammalian , Fibroblast Growth Factor 2/pharmacology , Gene Expression/drug effects , Glial Fibrillary Acidic Protein/metabolism , Immunohistochemistry/methods , Mice , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Neurons/drug effects , RNA, Messenger/metabolism , Reverse Transcriptase Polymerase Chain Reaction/methods , Stem Cells/drug effects , Time FactorsABSTRACT
We have developed a simple method to efficiently produce a large number of neural stem cells and neurons from mouse embryonic stem (ES) cells. When cultured in astrocyte-conditioned medium (ACM) with mitogens (FGF-2 and EGF) under free-floating conditions, colonies of undifferentiated ES cells give rise to neural stem spheres (NSSs), composed of plentiful neural stem cells. Subsequent culture of the NSSs on an adhesive substrate with mitogens results in the migration of neural stem cells onto the substrate. These cells can be expanded, preserved by freezing, and differentiated into functional neurons. Neural stem cells and neurons provided by this NSS method may be valuable as potential donor cells for neuronal transplantation and also as convenient alternatives to tissue-derived neural cells.
Subject(s)
Neurons/physiology , Stem Cells/physiology , Animals , Astrocytes , Cell Differentiation , Cell Movement , Cells, Cultured , Cryopreservation , Culture Media, Conditioned , Cytological Techniques , Electrophysiology , Epidermal Growth Factor/pharmacology , Fibroblast Growth Factor 2/pharmacology , Fluorescent Antibody Technique , Gene Expression Regulation/physiology , Mice , Mitogens/pharmacology , Patch-Clamp Techniques , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Pluripotent embryonic stem (ES) cells may differentiate into neurons in vitro. This is valuable in the study of neurogenesis and in the generation of donor cells for neuronal transplantation. Here we show that astrocyte-derived factors instruct mouse and primate ES cells to differentiate into neurons. Cultured in astrocyte-conditioned medium (ACM) under free-floating conditions, within 4 days, colonies of undifferentiated mouse ES cells give rise to floating spheres of concentric stratiform structure with a periphery of neural stem cells, which are termed Neural Stem Spheres. Culturing the spheres on an adhesive substrate in ACM promotes neurogenesis, and cells in the spheres differentiate into neurons within 5 days, including dopaminergic neurons. In contrast, neither astrocytes nor oligodendrocytes are formed. The procedure developed for mouse ES cells can be applied to monkey ES cells. This neurogenesis pathway provides a new insight into mechanisms of specification of cell fates in early development and also provides a simple procedure for fast and efficient generation of a vast number of neural stem cells and neurons.
