Vimentin and glial fibrillary acidic protein filaments in radial glia of the adult urodele spinal cord

This work, based on Golgi impregnations, transmission electron microscopy and immunocytochemistry, demonstrates that the intermediate filaments found in the radial gliocytes of the adult newt spinal cord are both vimentin and glial fibrillary acidic protein (GFAP) structures. Gliocytes appeared as large, arboreous cells, with appendages extending peripherally. They were extensively immunolabelled with both anti-vimentin and anti-GFAP monoclonal antibody conjugates. Outstanding correspondence in cell configuration was found when Golgi-impregnated specimens were compared to the distribution of immunolabels. Electron micrographs showed cytoplasmic bundles of anti-vimentin decorated intermediate filaments occupying the radial projections. The presence of GFAP confirms the astroglial character of the radial glia in urodeles; the existence of vimentin suggests that the spinal cord of the adult animal retains immature astroglia, which should express enlarged capabilities of adaptation.     

Immunotyping of radial glia and their glial derivatives during development of the rat spinal cord

Summary The differentiation of glia in the central nervous system is not well understood. A major problem is the absence of an objective identification system for involved cells, particularly the early-appearing radial glia. The intermediate filament structural proteins vimentin and glial fibrillary acidic protein have been used to define the early and late stages, respectively, of astrocyte development. However, because of the non-specificity of vimentin and the temporal overlap in expression patterns of both proteins, it is difficult to refine our view of the process. This is especially true of the early differentiation events involving radial glia. Using the developmentally-expressed intermediate filament-associated protein IFAP-70/280 kD in conjunction with vimentin and glial fibrillary acidic protein markers, a comprehensive investigation of this problem was undertaken using immunofluorescence microscopy of developing rat spinal cord (E13-P28 plus adult). The phenotypes of the cells were defined on the basis of their immunologic composition with respect to IFAP-70/280 kD (I), vimentin (V) and GFAP (G). A definitive immunotype for radial glia was established, viz, I⁺/V⁺/G^–; thus reliance upon strictly morphological criteria for this early developmental cell was no longer necessary. Based upon the immunotypes of the cells involved, four major stages of macroglial development were delineated: (1) radial glia (I⁺/V⁺/G^–); (2) macroglial progenitors (I⁺/V⁺/G⁺); (3) immature macroglia (I^–/V⁺/G⁺); and (4) mature astrocytes (I^–/V⁺/G⁺ primarily in white matter and I^–/V^–/G⁺, the predominant type in gray matter). It is of interest to note that the cells of the floor plate were distinguished from radial glia by their lack of IFAP-70/280 kD immunoreactivity. Introduction of the IFAP-70/280 kD marker has therefore provided a more refined interpretation of the various differentiation stages from radial glia to mature astrocytes.     

Evolutionary development of lymphocyte heterogeneity: leucocyte subpopulations in the Pacific hagfish

Flow cytometric analysis of forward angle versus 90 degree scatter patterns of hagfish peripheral blood revealed two distinct leucocyte populations with size characteristics analogous to mammalian monocytes/granulocytes (hagfish large leucocytes) and small lymphocytes (hagfish small leucocytes). A cell population enhanced for the small leucocytes was obtained by density gradient centrifugation. Over 70% of the small leucocyte population consistently stained with a rabbit antiserum directed against polypeptide determinants on hagfish immunoglobulin, while staining of the large cell population was greatly reduced (less than 10%). A panel of monoclonal antibodies raised against a crude hagfish leucocyte preparation distinguished the two cell populations and revealed the existence of subpopulations of both small and large leucocytes.     

Bicuspid and tricuspid aortic valve do not have the same ascending aorta morphology

Bicuspid aortic valves are associated with histopathological abnormalities of the aorta. Their diameters have been measured in several studies, but the literature concerning changes in the overall anatomy of the ascending aorta is limited. We wanted to know whether the anatomy of the valve, bicuspid or tricuspid, is associated with anatomical differences. We prospectively included patients requiring aortic valve surgery. The protocol included a chest CT scan before the operation to determine the angulations and straight lengths of aortic segments 0 and 1. All of the patients underwent surgery to assess their aortic valve morphology. We included 107 patients, 25 (23%) with bicuspid diagnostic valves and 82 (77%) with tricuspid ones. Most angulations were similar between the groups. However, the angle between the ring and the plane of the top of the commissures of the semilunar cusps was lower in bicuspid than tricuspid aortic valves. The straight lengths in the aortic root did not differ significantly, but the lengths separating these planes from the BCAT plane were consistently greater in the bicuspid group. The angle between the ring plane and the patient's vertical axis was lower in the bicuspid, the plane of the ring being verticalized in this group. In conclusion, we were able to confirm significant morphological differences in addition to the diameters. However, this study does not establish causal relationships among valve morphology, ascending aortic morphology, histology, and possibly associated pathologies. An extremely large cohort will be required indicate such causal connections. Clin. Anat. 31:693–697, 2018. © 2018 Wiley Periodicals, Inc.     

Development and structure of the radial glia in the postnatal rat brain

Summary Postnatal development of radial glial cells was examined in albino rats. Until the 10th postnatal day radial glial cells were seen in the lateral ventricles, in the third ventricle (throughout its whole extent), in the aqueduct and in the fourth ventricle. The morphological appearance of radial glial cells was very variable in the different regions.After the 10th day radial glial cells (tanycytes) were seen only in the wall of the third ventricle. According to their appearance it was possible to undertake a morphological grouping. Considerable changes of the morphology of individual tanycytes could be observed in the median eminence and in the ventral hypothalamus between the 5th and 21st days.It was found that the peripheral processes of tanycytes ended near the nerve cells or on the cell body, on capillaries of the hypothalamic nuclei or on the pial surface. In a number of cases one tanycyte process contacted both the blood vessels of the hypothalamus and the pial surface.In view of their morphology the tanycytes can be assumed to transport material between different extracellular spaces, and/or to excrete material.The radial glial cells of the lateral ventricles can serve as guides for the postnatally formed microneurons and later can either transform to astroglia or degenerate.Part of this work was presented at the Annual Meeting of the Japanese Anatomical Society in Tokyo, 1979     

The glia doctrine: Addressing the role of glial cells in healthy brain ageing

Glial cells in their plurality pervade the human brain and impact on brain structure and function. A principal component of the emerging glial doctrine is the hypothesis that astrocytes, the most abundant type of glial cells, trigger major molecular processes leading to brain ageing. Astrocyte biology has been examined using molecular, biochemical and structural methods, as well as 3D brain imaging in live animals and humans. Exosomes are extracelluar membrane vesicles that facilitate communication between glia, and have significant potential for biomarker discovery and drug delivery. Polymorphisms in DNA repair genes may indirectly influence the structure and function of membrane proteins expressed in glial cells and predispose specific cell subgroups to degeneration. Physical exercise may reduce or retard age-related brain deterioration by a mechanism involving neuro-glial processes. It is most likely that additional information about the distribution, structure and function of glial cells will yield novel insight into human brain ageing. Systematic studies of glia and their functions are expected to eventually lead to earlier detection of ageing-related brain dysfunction and to interventions that could delay, reduce or prevent brain dysfunction.     

An investigation of astroglial morphology in torpedo and scyliorhinus

The distribution and morphology of GFAP-immunoreactive cells was investigated in two elasmobranch species, Scyliorhinus canicula and Torpedo marmorata, in an attempt to distinguish between Horstmann's (1954) hypothesis that the presence of cells resembling mammalian astrocytes is a function of the thickness of the ventricular walls, and Cajal's (1911) hypothesis that astrocytes are a phylogenetic novelty found only in birds and mammals. Two types of GFAP-reactive elements were observed, but the distribution of these differed markedly between the two species. In Scyliorhinus, radial glial cells were predominant and astrocytes relatively rare. In Torpedo, on the other hand, a species in which the ventricles are atrophied and the ventricular walls extremely thick, the overwhelming majority of GFAP-labelled structures strongly resembled astrocytes; occasionally, GFAP-positive cells were observed in the ependyma of the spinal cord. These findings, together with previous results obtained by others in hagfish, provide strong evidence in favour of Horstmann's hypothesis.     

Production and specificity of antibodies to streptococci in the Pacific hagfish, Eptatretus stoutii.

Specific antibody activity at high levels to group A streptococcal carbohydrate was detected by radioimmunoassay in the sera of certain hagfish immunized with streptococcal whole cells. Antigen binding activity could be depleted by absorption of immune serum with streptococcal cells but not with sheep erythrocytes. Sugar inhibition studies indicated that rhanmose was the immunodominant sugar recognized in the A carbohydrate by hagfish antibody. This was in contrast to previous identification of N-acetylglucosamine as the immunodominant sugar recognized by antibodies from mammalian species.     

Dopaminergic cells align along radial glia in the developing mesencephalon of the rat

Studies were performed to examine the relation of dopaminergic cells and radial glia in the developing mesencephalon of the rat at ages E12-E20. Dopaminergic cells were immunolabelled with an antiserum which recognizes tyrosine hydroxylase, and radial glia were immunolabelled with a monoclonal antibody which recognizes vimentin. The vimentin-immunoreactive fibres of radial glia were noted at E12. At E12, and more clearly at later time points, the radial glia extended from the aqueduct to the pial surface, and this pattern persisted throughout the prenatal period. Tyrosine hydroxylase-immunoreactive cells were located along the ventral surface of the mesencephalon at age E13. At age E15, E16, and E18 the tyrosine hydroxylase-immunoreactive cells were present from the aqueduct to the ventral pial surface of the mesencephalon and were aligned along radial glia. Our study suggests that radial glia provide paths for migration of dopaminergic cells in the mantle layer from E15 to E18 of the developing mesencephalon. It also suggests that some dopaminergic cells between E15 and E18 may express tyrosine hydroxylase during their migration through the mantle layer and prior to reaching the location they occupy in the adult brain.     

Radial glial cells derived from the neonatal rat spinal cord: morphological and immunocytochemical characterization

Radial glial cells are transiently bipolar cells in the developing central nervous system, best known for their role in guiding migrating neurons. The aim of the present study was to investigate phenotypic characteristics of these bipolar precursor cells in a mixed glial cell culture system derived from the rat neonatal spinal cord. Morphological characterization was assessed by cell-specific immunocytochemical markers (nestin, vimentin, 3CB2) and transmission electron microscopy. Our study yielded substantial evidence showing that the bipolar cells exhibit immunocytochemical and ultrastructural features of radial glial cells. Immunohistochemistry of the neonatal rat spinal cord using the same cell-specific markers suggested these cells are likely derived from the subependymal zone, ventral commissure, and dorsomedial septum. We believe our data recommend this mixed glial culture system to be a valuable tool in studying radial glial cells in vitro.     

Notch-regulated oligodendrocyte specification from radial glia in the spinal cord of zebrafish embryos

During vertebrate neural development, many dividing neuroepithelial precursors adopt features of radial glia, which are now known to also serve as neural precursors. In mammals, most radial glia do not persist past early postnatal stages, whereas zebrafish maintain large numbers of radial glia into adulthood. The mechanisms that maintain and specify radial glia for different fates are still poorly understood. We investigated formation of radial glia in the spinal cord of zebrafish and the role of Notch signaling in their maintenance and specification. We found that spinal cord precursors begin to express gfap+, a marker of radial glia, during neurogenesis and that gfap cells give rise to both neurons and oligodendrocytes. We also determined that Notch signaling is continuously required during embryogenesis to maintain radial glia, limit motor neuron formation and permit oligodendrocyte development, but that radial glia seem to be refractory to changes in Notch activity in postembryonic animals.     

An investigation into the distribution of radial immunodiffusion quality control data.

Quality control data from routine radial immunodiffusion assays for IgG, IgA, IgM, C3, C4 and alpha1-antitrypsin were tested by the Kolmogorov--Smirnov procedure for gaussian distribution. All but alpha1-antitrypsin were nongaussian in type. Further analysis of these date by plotting on log-normal probability paper showed them to have a log-normal distribution. Treatment of the date by either gaussian or nonparametric statistical methods produced little difference in confidence limits. It does not appear necessary to use nonparametric methods to calculate confidence limits from quality control data for the procedures studied.     

Role of radial glia in cytogenesis, patterning and boundary formation in the developing spinal cord

Radial glial fibres provide a transient scaffold and impose constraints in the developing central nervous system (CNS) that facilitate cell migration and axon growth. Recent reports have raised doubts about the distinction between radial glia and precursor cells by demonstrating that radial glia are themselves neuronal progenitor cells in the developing cortex, indicating a dual role for radial glia in both neurogenesis and migration guidance. Radial glia shift toward exclusive generation of astrocytes after neurogenesis has ceased. Radial progenitor cell differentiation and lineage relationships in CNS development are complex processes depending on genetic programming, cell-cell interaction and microenvironmental factors. In the spinal cord, radial cells that arise directly from the neuroepithelium have been identified. At least in the spinal cord, these radial cells appear to be the precursors to radial glia. It remains unknown whether radial glial cells or their precursors, the radial cells, or both can give rise to neurons in the spinal cord. Radial glial cells are also important in regulating the axon out-growth and pathfinding processes that occur during white matter patterning of the developing spinal cord.     

Organization of radial glia and related cells in the developing murine CNS. An analysis based upon a new monoclonal antibody marker

A monoclonal antibody, RC1, has been generated which provides a selective and sensitive immunohistochemical marker of radial glial cells and related cell forms during development of the mouse CNS. Beginning on embryonic day E10, immunocytochemistry performed on cryostat sections stains throughout the CNS a subpopulation of cells in the ventricular zone with radial processes that terminate with endfeet at the pial surface. These processes become fasciculated and attain maximal densities by E12-14 in the spinal cord and lower brainstem and by E14-16 in the midbrain, cerebellum and forebrain. Fasciculation is especially prominent for a subclass of these cells at the midline of the brainstem and spinal cord. As nuclear and cortical structures develop, the trajectories of the radial fiber fascicles undergo systematic and region-specific distortions in their initially simple linear configuration, in the process maintaining a consistent spatial registration of germinal ventricular zones with distal sites of assembly of post-migratory neurons. In the late fetal period, radial glial progressively disappear and scattered immature astrocytes bearing multiple fine processes appear in most regions of the CNS. In the spinal cord, a transitional unipolar radial form is identified in the emerging ventral and lateral funiculi between E13 and E17. In the cerebellum, precursors to the unipolar Bergmann glial cell are identified by E15, and in the retina, precursors of the bipolar Müller cell are identified by E16. Postnatally, RC1-stained radial glia become sparse, and after one week, immunoreactive cells include only ependymal cells, hypothalamic tanycytes, Bergmann glia, Müller cells, a unipolar radial form in the dentate gyrus, and a subpopulation of white matter astrocytes. These results suggest that radial cells of astroglial lineage comprise a diverse set of cell classes which subserve multiple functions in the developing and adult brain.     

Histochemistry of glycogen deposition in perinatal rat brain: importance of radial glial cells

Summary Changes in the glycogen content and patterns of deposition in the developing rat brain were studied using a light microscopic periodic acid-Schiff method on embryonic days (ED) 14, 16, 18, 20 and postnatal days (PD) 1, 3, 7, 12, 16 and 21. Regional and temporal differences were quantified with an automatic image analyser by estimation of stained material in subpial regions of cerebral cortex, thalamus, superior colliculus and medulla. The cellular localization of glycogen particles was investigated by electron microscopy on ED 18, ED 20 and PD 2. On ED 14 the first signs of glycogen storage were found in parts of the immature choroid plexus and in radial glial cells in the midbrain and medullary raphé. With advancing foetal age these structures retained their high capacity for glycogen storage but, in addition, an increasing number of radial fibres in most of the brain stem regions and in the cerebral cortex of older foetuses (ED 18–20) showed significant amounts of glycogen. The storage of glycogen in cerebral cortex was relatively low at all foetal age intervals studied. In new born animals the distribution of glycogen particles was similar to that found in the late foetal brain. A decrease of glycogen content commenced from PD 1 to 3 and reached the pattern of the adult brain between PD 7 and 21.Glycogen storage by radial glial cells in the developing rat brain might indicate their possible role as an energy source in perinatal carbohydrate metabolism.     

海马放射状胶质细胞的体外诱导激活及其意义

为探讨海马放射状胶质细胞在切割穹窿海马伞侧海马提取液的诱导下形态发生的变化,将培养的海马胶质细胞接种于24孔培养板中,分成诱导组和对照组,诱导组加入含5%切割穹窿海马伞侧海马提取液的DMEM/F12培养液,对照组加入单纯的细胞培养液,分别于培养后1、3、7和14d时行BLBP免疫荧光检测和Hoechst标记。计算两组各天时BLBP阳性细胞占Ho-echst阳性细胞的百分比,并用LeicaQiwn图像处理软件检测BLBP阳性细胞的周长和面积(含突起)。Stata8.0统计软件行组间比较。结果显示,1d时诱导组BLBP阳性细胞的比例稍高于对照组,两组细胞胞体均较小,突起均较短较细,无明显差异;3d时,诱导组BLBP阳性细胞的比例明显高于对照组,且胞体较大,突起较粗较长;7d时诱导组BLBP阳性细胞的比例明显高于对照组达到高峰,胞体更大,突起更粗更长交织成网;14d时两组BLBP阳性细胞的比例均稍有降低,但诱导组的比例仍明显高于对照组,两组细胞的胞体稍变小,突起稍变细变短。上述结果提示,切割穹窿海马伞侧海马提取液可明显地诱导BLBP阳性放射状胶质细胞增殖,并使胞体变大,突起变粗变长,呈"激活"状态。     

An investigation of mutation as a function of age in humans

An accumulation of mutations on their own or together with other age-related changes may contribute to ageing and the development of age-related pathologies. The aim of this investigation wass to assess the extent of DNA mutations as a function of age in humans. The mutant frequency (MF) at the hypoxanthine-guanine phosphoribosyl-transferase (hgprt) locus was assessed in lymphocytes isolated from male volunteers in each of three age groups (35–39, 50–54 and 65–69 years). Results show that the mean MF in the 65–69 years group was approximately twice that in the 35–39 and 50–54 years (4.1/10⁶ cells, 1.9/10⁶ cells and 1.79/10⁶ cells, respectively) increasingly by about 1.33% per year, after 54 years. In addition, there was an increased frequency of chromosomal aberrations in the 65–69 years group compared to the other two age groups. The results of this investigation show an increase in DNA mutations in cultured human lymphocytes with age. Factors which may influence the extent of DNA damage in human lymphocytes are discussed.     

An investigation of grief and adaptation in parents whose children have died from cancer

The experiences and adaptation of 54 parents were studied from2 months to 3 years following the death of their child fromcancer. There appears to be a phenomenon in the 3rd year ofbereavement which is associated with an intensification of thegrief experience and suggests that parental bereavement mayactually worsen with time. Other findings indicate that thereare "optimum" amounts of anticipatory grief, participation withthe hospitalized child, and lengths of illness, below and abovewhich parental adjustment is compromised. Anticipatory griefwas found to have statistically significant salutary effects.Parental participation during the child's hospitalization wasfound to be significantly associated with higher ratings ofparental satisfaction with the child's treatment. Overall mothersappeared to sustain grief experiences reflective of higher degreesof intensity and poorer adjustment as compared to fathers, althoughonly to a statistically significant level on two variables.The amount of support received during the illness had a mixedeffect upon the parents' grief and adjustment. Previous losstended to be associated with poorer bereavement outcomes andlower anticipatory grief.