Development and differentiation of astrocytes and oligodendrocytes (OC) in the developing human fetal spinal cord (HFSC) have been investigated by the correlative analysis of light microscopic, EM, Golgi and immunocytochemical studies. The evidence is presented to suggest, (a) that radial glia are the first distinguishable neuroglial element among the cells within the ventricular zone, (b) that radial glia contains astrocyte-specific glial fibrillary acidic protein (GFAP), (c) that radial glia undergoes transformation into astroglial cells, (d) that "transitional forms" possessing the light and EM features of both astroglial and oligodendroglial cells appear just prior to the onset of myelination, and (e) the myelin-forming OC are most likely derived from radial glial cells, either directly or through intermediated astroglial forms.
Human ; In Vitro ; Microscopy, Electron ; Neuroglia/ultrastructure* ; Oligodendroglia/ultrastructure* ; Spinal Cord/embryology* ; Spinal Cord/ultrastructure

The distribution of the nerve growth factor (NGF), the glial fibrillary acidic protein (GFAP) and the ciliary neurotrohic factor (CNTF) was performed in coronal sections of the mesencephalon, rhombencephalon and spinal cord in the developing Mongolian gerbils. Generally, NGF specifically recognizes neurons with the NGF receptor, whereas GFAP does the glia, and CNTF does the motor neurons. The receptor expression was examined separately in gerbils between embryonic days 15 (E15) and postnatal weeks 3 (PNW 3). The NGF-IR was first observed in the spinal cord at E21, which might be related to the maturation. The GFAP reactivity was peaked at the postnatal days 2 (PND2), while the highest CNTF-reaction was expressed at PNW 2. The GFAP stains were observed in the aqueduct and the spinal cord, which appeared to project laterally at E19. The CNTF was observed only after the birth and found in both the neurons and neuroglia of the substantia nigra, mesencephalon, cerebellum and the spinal cord from PND1 to PNW3. These results suggest that NGF, GFAP and CNTF are important for the development of the neurons and the neuroglia in the central nervous system at the late prenatal and postnatal stages.
Animals ; Brain Stem/enzymology/*metabolism ; Ciliary Neurotrophic Factor/*metabolism ; Embryonic and Fetal Development/physiology ; Female ; Gerbillinae/*embryology ; Glial Fibrillary Acidic Protein/*metabolism ; Immunohistochemistry/veterinary ; Mesencephalon/embryology/metabolism ; Nerve Growth Factor/*metabolism ; Pregnancy ; Rhombencephalon/embryology/metabolism ; Spinal Cord/embryology/*metabolism

AIMTo investigate the expression of androgen receptors in the extragenital tissues of developing human embryo.

METHODSUsing immunohistochemistry, we investigated the distribution of androgen receptor (AR) in the extragenital tissues of paraffin-embedded tissue sections of first trimester (8-12 weeks gestation) human embryos. Gender was determined by polymerized chain reaction.

RESULTSThere were no differences in the expression and distribution of AR in male and female embryos at any stage of gestation. AR expression was seen in the thymus gland. The bronchial epithelium of the lungs showed intense positive staining with surrounding stroma negative. Furthermore, positive staining for androgen receptor was exhibited in the spinal cord with a few positive cells in the surrounding tissues. Cardiac valves also showed strong positive staining but with faint reactivity of the surrounding cardiac muscle. There was no staining in kidney, adrenal, liver or bowel.

CONCLUSIONThis study demonstrates that immunoreactive AR protein is present in a wide variety of human first trimester fetal tissues and shows the potential for androgen affecting tissues, which are mostly not considered to be androgen dependent. Moreover, it implies that androgen might act as a trophic factor and affect the early development of these organs rather than simply sexual differentiation.

Bronchi ; cytology ; embryology ; metabolism ; Female ; Fetus ; cytology ; metabolism ; Heart ; embryology ; Humans ; Immunohistochemistry ; methods ; Male ; Myocardium ; cytology ; metabolism ; Pregnancy ; Pregnancy Trimester, First ; Receptors, Androgen ; genetics ; metabolism ; Spinal Cord ; cytology ; embryology ; metabolism ; Thymus Gland ; cytology ; embryology ; metabolism

To elucidate the early sequential morphogenetic progress of exencephaly and myeloschisis, rat embryos whose mothers had been treated with hypervitaminosis A were studied at 1-day interval from gestation day 10.5 to 15.5. In exposed animals sequential change was found in both exencephaly and myeloschisis as the embryos grew up. The 10.5-day old exencephalic embryos had still widely open cephalic neural tubes. Exencephalic embryos older than 13.5 days of gestation showed strikingly severe eversion and overgrowth of the cephalic neuroepithelium, thus failed in forming normal primitive brain. The convex dorsal surface of the exencephaly was covered with ependyma, which was connected directly with surrounding surface eqithelium at the periphery. The earliest morphologically recognized myeloschisis was in the 13.5-day old embryos. In myeloschisis, divergence at the roof plate and eversion of the spinal neural tube, disorganized overgrowth of the neuroepithelium, malformed and misplaced spinal ganglia and nerve roots, and absence of the neural arch and dermal covering were characteristic. It is suggested that exencephaly results from failure of the cephalic neural tube closure which is followed by eversion and overgrowth of the neuroepithelium. And failure in closure of the posterior neuropore and disturbance in the development of the tail bud probably play major role in the morphogenesis of myeloschisis.
Animals ; *Embryonic and Fetal Development ; Female ; Hypervitaminosis A ; Neural Tube Defects/chemically induced/*pathology ; Pregnancy ; Rats ; Rats, Inbred Strains ; Spinal Cord/*abnormalities/embryology

Intracranial and spinal dural arteriovenous fistulas (DAVFs) are vascular pathologies of the dural membrane with arteriovenous shunts. They are abnormal communications between arteries and veins or dural venous sinuses that sit between the two sheets of the dura mater. The dura propria faces the surface of brain, and the osteal dura faces the bone. The location of the shunt points is not distributed homogeneously on the surface of the dural membrane, but there are certain areas susceptible to DAVFs. The dura mater of the olfactory groove, falx cerebri, inferior sagittal sinus, tentorium cerebelli, and falx cerebelli, and the dura mater at the level of the spinal cord are composed only of dura propria, and these areas are derived from neural crest cells. The dura mater of the cavernous sinus, transverse sinus, sigmoid sinus, and anterior condylar confluence surrounding the hypoglossal canal are composed of both dura propria and osteal dura; this group is derived from mesoderm. Although the cause of this heterogeneity has not yet been determined, there are some specific characteristics and tendencies in terms of the embryological features. The possible reasons for the segmental susceptibility to DAVFs are summarized based on the embryology of the dura mater.
Arteries ; Brain ; Cavernous Sinus ; Central Nervous System Vascular Malformations ; Colon, Sigmoid ; Dura Mater ; Embryology ; Membranes ; Mesoderm ; Neural Crest ; Pathology ; Population Characteristics ; Spinal Cord ; Veins

OBJECTIVESTo study the expression patterns of two Eph family molecules, the receptor EphA5, and the ligand ephrin-A5, during spinal cord development.

METHODSThe receptor expression was analyzed using beta-galactosidase knockin mice, and affinity ligand probe binding. The ligand expression was assessed using two different affinity probes, and knockout mouse tissues as controls.

RESULTSEphA5 was expressed in the ventral spinal cord, while ephrin-A5 was located in the dorsolateral regions of the spinal cord throughout development.

CONCLUSIONSThese results show that EphA5 and ephrin-A5 are expressed over broad developmental stages and may play important roles in establishing the dorsoventral organization of the spinal cord.

Animals ; Ephrin-A5 ; biosynthesis ; Gene Expression ; Gene Expression Regulation, Developmental ; Immunohistochemistry ; Mice ; Mice, Inbred C57BL ; Mice, Mutant Strains ; Receptor, EphA5 ; biosynthesis ; Spinal Cord ; embryology ; metabolism

Spinal cord injury and regeneration involves transcriptional activity of many genes, of which many remain unknown. Using the rat spinal cord full- transection model, bioinformatics, cloning, expression assays, fusion proteins, and transfection techniques, we identified and characterized one such differentially expressed gene, termed scirr1 (spinal cord injury and/or regeneration related gene 1). Fourteen orthologs were found in 13 species from echinoderm to insect and human by Blast search of NCBI protein reference sequence database. However, no further information is available for these homologues. Using whole-mount in situ hybridization, mouse scirr1 mRNA was expressed temporally and spatially in accordance with the early development sequence of the central nervous system. In adult rat spinal cord, expression of scirr1 mRNA was localized to neurons of gray matter by in situ hybridization. Using immunohistochemistry, SCIRR1 protein was found to be up-regulated and expressed more highly in spinal cord neurons farther from the epicenter of injury. Although the precise function of SCIRR1 is unknown, its unique pattern of expression during CNS early development and up-regulation after spinal cord injury suggest that SCIRR1 should be involved in the succeeding injury and/or repair processes of the injured spinal cord. Also, the typical F-box and leucine-rich repeat (LRR) architecture of rat SCIRR1 indicated that it may play an important substrate recruiting role in the pleiotropic ubiquitin/proteasome pathway. All these make scirr1 a new interesting start to study the spinal cord injury and regeneration mechanism.
Amino Acid Sequence ; Animals ; Base Sequence ; Brain/embryology/metabolism ; Embryo, Mammalian/metabolism ; F-Box Proteins/*biosynthesis ; Gene Expression Regulation, Developmental ; Male ; Mice ; Molecular Sequence Data ; Organ Specificity ; PC12 Cells ; Phylogeny ; Rats ; Rats, Wistar ; Spinal Cord/embryology/metabolism ; Spinal Cord Injuries/*metabolism ; Up-Regulation

Wnt inhibitor factor-1 (WIF-1) is an extracellular antagonist of Wnts secreted proteins, first characterized as an expressed sequence tag in the human retina. WIF-1 belongs to the secreted Frizzled-related protein (sFRP) class, which can directly bind to Wnt proteins, prevent Wnts from binding to their receptors in vertebrates. Wif1 is expressed in the nervous system of mouse, Xenopus, zebrafish and human. It has been shown that WIF-1 affects the formation of somites in Xenopus embryos and inhibits rod production in retinal histogenesis by binding to Wnt4 in mice. Histological information of Wif1 expression during the development of the central nervous system has been reported in mouse, Xenopus and zebrafish and the strong embryonic expression suggests Wif1 may play an essential role in the spatial and temporal regulation of Wnt signals in development of central nervous system. The Wnt pathway plays a key role in the patterning of the nervous system. However, insights into the function of Wif1 in the development of the central nervous system are rather limited. Selecting suitable stage and target according to the expression pattern may contribute to understanding the function of Wif1.
Adaptor Proteins, Signal Transducing ; biosynthesis ; physiology ; Animals ; Brain ; embryology ; metabolism ; Central Nervous System ; embryology ; metabolism ; Extracellular Matrix Proteins ; biosynthesis ; physiology ; Gene Expression ; Humans ; Intercellular Signaling Peptides and Proteins ; biosynthesis ; physiology ; Mice ; Repressor Proteins ; biosynthesis ; physiology ; Signal Transduction ; physiology ; Spinal Cord ; embryology ; metabolism ; Xenopus

OBJECTIVETo investigate the influence of exposure to different concentrations of ethanol on neural progenitor cells and the differentiation of neurons and glial cells in zebrafish embryos.

METHODSZebrafish embryos were exposed to 1%, 2%, and 2.5% (V/V) ethanol at 5 hpf by adding ethanol to the egg water. In situ hybridization and real-time PCR were used to detect the changes in the mRNA expression profiles of the markers of different cells to examine the effects of alcohol on neural development.

RESULTSThe number of neural precursor cells, neurons and mature glial cells was significantly reduced in the zebrafish embryos following ethanol exposure, and this reduction became more prominent as the ethanol concentration increased. The expression of the early glial marker slc1a3a was down-regulated in the spinal cord but increased in the brain after exposure to increased ethanol concentrations. The expression of the mature glial markers was significantly lowered in response to exposure to increasing ethanol concentrations.

CONCLUSIONSEthanol can reduce neural precursor cells and inhibits neuronal and glial differentiation in zebrafish embryos.

Animals ; Brain ; Cell Differentiation ; drug effects ; Embryo, Nonmammalian ; drug effects ; Ethanol ; adverse effects ; Neural Stem Cells ; drug effects ; Neurogenesis ; drug effects ; Neuroglia ; drug effects ; Neurons ; drug effects ; Spinal Cord ; Zebrafish ; embryology