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At least 73 records · Page 4Linked to original sources

PubMed2005

Adeno-associated virus type 4 (AAV4) targets ependyma and astrocytes in the subventricular zone and RMS.

The subventricular zone (SVZ) is one of the neurogenic niches in the adult mammalian brain. The SVZ is of interest for studies on neurogenesis and stem cell therapy. Here, we report specific transduction of ependyma and/or astrocytes by recombinant adeno-associated virus type 4 (AAV4) viral vectors. AAV4 vectors encoding beta-galactosidase or eGFP were injected into the lateral ventricles of neonatal and adult C57BL/6 mouse brains. In addition, SVZ injections were conducted on adult mice. AAV4 vectors show a characteristic transduction of the ependyma independent of delivery route. However, AAV4 virus injected into the SVZ targeted GFAP positive astrocytes forming the glial tube in the SVZ and rostral migratory stream (RMS). Our results introduce AAV4 as a new tool by which to manipulate glial cells in the RMS.

Animals↗

PubMedDate not supplied

Ultrastructural effects of Conray 60 and Pantopaque on ependyma and choroid plexus following intraventricular injections.

Electron microscope evaluation of choroid plexus and ependyma following single cerebral intraventricular injections of Conray 60 and Pantopaque was carried out on 35 rats and 4 dogs. The animals were sacrificed at periods ranging from 1 hour to 4 months. Conray was not detected with the light or electron microscope; however, Pantopaque was presumptively localized as electron-dense masses associated with lipid-like bodies at the ventricular interface of both choroidal and ependymal epithelium. Conray 60 injections consistently induced convulsions in rats. Histological studies demonstrated moderate cellular damage and multilayered proliferation of ependymal epithelium. Morphological damage following Pantopaque was more severe and widespread in both choroid plexus and ependyma suggesting that, of the two agents, Conray may have the greater clinical potential provided that the associated convulsions are controlled by appropriate measures.

Animals↗

PubMed1998

Fetal ependyma in sheep and goat. A scanning electron microscopy study.

Morphology of the surface of apical membranes of ependymal cells has been studied in the whole ventricular system of the brain in goat and sheep fetuses using a scanning electron microscope. The surface structure of the ependymal lining surface in fetuses of small ruminants is very similar to that in adult animals. Supraependymal cells were found only in the lower part of the third cerebral ventricle in goat fetuses, but not in sheep fetuses. In small ruminants the ependymal surface is already regionally differentiated within the end of the first half of prenatal development. Fetal ependyma of goats and sheep, unlike the adult ependyma, is characterized by a high secretory activity, which is independent of sex or age of fetuses.

Animals↗

PubMed1977

Histological observations on the ependyma of the ventriculus mesencephali in the guinea pig.

The ventriculus mesencephali is localized in front of the cerebellum and forms a recessus of the dorsal wall of the aquaeductus mesencephali. The ependyma was found one-layered; in some places clusters of cubic or cylindrical ependymal cells occur. Some cells show basal processes. Supra-ependymally there are homogeneous globules and intraventricular nerve fibres. The occurrence of different types of ependymal cells indicates a morphological variability of ependyma even within this small part of the ventricle system of the brain.

Animals↗

PubMed1987

Ependyma of the rat fourth ventricle and central canal: response to injury.

The response of ependyma in the fourth ventricle and central canal to injury was investigated in young Sprague-Dawley rats. Animals received either a small unilateral incision in the lateral funiculus of the thoracolumbar (TL) cord or a puncture wound in the dorsolateral medulla. Control and lesioned rats were killed from 2 to 21 days after operation and the tissue encompassing the lesions was processed for light microscopy and transmission electron microscopy. Randomly selected lesioned and control rats received colchicine (0.2 mg/100 g s.c.) 6 h prior to death at postoperative days 1-4. In controls, the central canal of the TL cord was lined by a single layer of uniformly arranged columnar ependymal cells with large basally located nuclei and apically displaced organelles. Prominent membrane fusions and condensations of filaments were consistent features of the apical region of these cells. Their basal poles abutted directly on the subjacent neuropil and occasionally gave rise to radially directed processes. In rats with TL lesions, the lumen of the central canal was collapsed and lined by an irregularly contoured, multilayered appearing ependyma. Ependymal cells were often radially elongated and possessed filament-filled basal processes. Mitotic rates among ependymal cells of lesioned rats reached a maximum of 3.34% on day 2 compared to 0.21 and 0.28% in intact and sham-operated controls, respectively. Mitotic activity declined progressively thereafter and approached control values by day 4. A similar but less pronounced pattern of proliferative activity was seen distal to the cord lesion, however, little activity was observed within the lining of the fourth ventricle of animals with comparable lesions in the medulla.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1999

Anomalous ependyma inducing split cord and meningomyelocele?

The case is that of a female fetus of 17 to 18 weeks' gestation with major defects of the central nervous system: (1) The thoracic vertebrae demonstrated rachischisis, with segmental diplomyelia; the duplicated cords were dissimilar in size and lay side by side within a single meningeal sheath lacking a dividing septum or spur. Cranially to the divided cord lay an unsplit segment of "open cord" lacking the posterior elements and exposing the centrally placed ependyma of the central canal flanked by glial and epidermal lining, respectively; it could be regarded as an example of a meningomyelocele. (2) Heterotopic massed ependymal cells, some of which were actively proliferating, were associated with the choroid plexus in the brain. Minor anomalies included cerebellar heterotopia and the malpositioning of dorsal root ganglia outside the meningeal sheath. Because the ependyma is such a powerful inducer of the development of neighboring tissue, the findings could be united by a common pathogenic theme, viz problematic ependymal development and migration within both the brain and spinal cord. The causative agent responsible for these abnormalities remains unidentified, but the balance of evidence suggests that its effect was felt during the second week of postconceptual age.

Abnormalities, Multiple↗

PubMed2001

FGF-2 immunoreactivity in adult rat ependyma and choroid plexus: responses to global forebrain ischemia and intraventricular FGF-2.

Fibroblast growth factor 2 (FGF-2) immunoreactivity (IR) was examined in the ependyma and choroid plexus (CP) of lateral and third ventricles in normal adult rats, as well as in response to transient forebrain ischemia (TFI) and exogenous FGF-2 delivered intraventricularly for several days by osmotic pump. Similar patterns of FGF-2 IR were seen in the CP epithelia of both lateral and third ventricles, as well as in ependymal cells of the third ventricle and along lateral sides of the lateral ventricles. Consistent staining was seen along the apical aspect of epithelial cells facing the cerebrospinal fluid (CSF). Cytoplasmic staining was seen in the absence of ischemia, and was dramatically reduced in response to TFI. FGF-2 treatment followed by TFI resulted in sustained FGF-2 IR within CP and ependymal cells, supporting the idea that these tissues are involved in synthesis and secretion of growth factors into the CSF. In contrast, along the medial sides of the lateral ventricles, adjacent to brain structures such as the hippocampus, consistent staining was seen along the basal aspect of the ependymal cells. We propose that at least some regions of ependyma may function to transport molecules such as FGF-2 directly into the underlying brain parenchyma.

Animals↗

PubMedDate not supplied

Ependyma-lined cysts.

Ependyma-lined cystic lesions of the subarachnoid space are uncommon. They form a histologically heterogeneous group and have been referred to as epithelial, ependymal, glioependymal and neuroepithelial cysts depending on their respective histological characteristics. In this report, we describe two cases of ependyma-lined cysts in the posterior fossa that support a common pathogenesis for this diverse group of lesions.

Adult↗

PubMed1991

Detection of herpes simplex virus in the ependyma of experimentally infected mice.

Forty-five Swiss albino mice were inoculated with HSV-1 (strain McKrae) by the corneal route. The spread of HSV to the brain stem and the ventricular ependyma was investigated. The polymerase chain reaction (PCR) was used to detect HSV-DNA in the CSF during the course of infection. The ependyma of the third and fourth ventricle and the central canal contained viral antigen at a late stage of infection in up to 60% of mice. At this stage we found that many animals gave a positive PCR in the CSF although no antigen could be detected in the ependymal cells. The presence or absence of antigen containing cells could not be related to detection of HSV-DNA in the CSF. The results show that infection of the ventricular wall is not important for the spread of HSV to the CSF.

Animals↗

PubMedDate not supplied

Changes in the hypothalamus and ependyma of the third ventricle of the brain in sheep after irradiation and hormone stimulation.

In the present study the authors focused their attention on the studies of PAS positive mucopolisaccharides in the hypothalamus and ependyma of the third ventricle and on the observation of changes in the volume of cell nuclei of neurons--nucl. supraopticus (NSO), nucl. hypothalamicus ventromedialis (NVM) and nucl. tuberomammillaris (NTM) in sheep after irradiation with 2.46 Gy and hormone stimulation during anestrous. Ageline sponges and serum gonadotropins were used for estrous synchronization and hormone stimulation, respectively. The increased amount of PAS positive substances found in the examined hypothalamic nuclei after irradiation and hormone treatment seem to stimulate the function of the hypothalamic structures. The results of caryometric analysis in spring sheep also confirm this view. Administration of hormones in combination with irradiation results in increased number of ependyma cells and desquamation of the surface layers.

Animals↗

PubMed1988

[Qualitative and quantitative changes in the hypothalamus and the ependyma of the 3d cerebral ventricle in sheep after irradiation and hormonal stimulation].

In the submitted work we concentrated our attention on the study of the changes in neurosecretion. PAS positive mucopolysaccharides in the hypothalamus and ependyma of the IIIrd cerebral ventricle and on studying the changes in the volume of the cell nuclei of the neurons of nucl. supraopticus (NSO), nucl. hypothalamicus centromedialis (NVM) and nucl. tuberomamillaris (NTM) of sheep after irradiation and after hormonal stimulation. We made our observations on 28 sheep of the Slovak Merino breed, of average live weight 35 to 40 kg, two- and three-years old in the period of physiological anoestrum. The first group of four ewes and the second group of four yearling lambs were controls. The third group of six ewes and the fourth group of six yearlings were exposed to irradiation all over with a dosage of 2.46 Gy (250 R) for a period of five days. To synchronize the oestrum of all the sheep we used agelline sponges which we fitted five days before irradiation. After the irradiation and removal of the sponges we gave the test sheep hormonal stimulation with 3 X 500 i. u. of serum gonadotropin. The fifth group of four ewes and the sixth group of four yearlings were only stimulated without irradiation. The fifth day after stimulation we slaughtered the sheep. We processed the brain samples by the usual histological methods. We carried out karyometric analysis with 3000X magnification and the measurement of 200 cells from one sample. We processed the values obtained mathematically according to Fischer and Inke (1956). We evaluated the quantity of neurosecretion material with a light microscope according to Nakahara (1962). We found that the multiplication of neurosecretion and the increased activity of the PAS reaction in the hypothalamic nuclei studied show that the irradiation and hormonal treatment stimulate the function of the hypothalamic structures. The results of the karyometric analysis in the yearlings also confirm this opinion. In the ewes the inhibitive influence of irradiation was probably manifest. The giving of hormones in combination with irradiation causes the multiplication of ependyma cells and the desquamation of surface layers.

Animals↗

PubMed1986

[Age and changes in nerve endings on the surface of the ependyma of the human brain].

Using scanning electron microscopy, the human brain ependyma was studied in different age groups (18-98 years). Sphere-shaped structures directly connected with the cellular surface were found on the surface of ependymal cells. In patients over 60 years such formations were flattened and deformed, sometimes completely destroyed. The detected age-related changes are considered as manifestations of atrophy of neuronal endings localized on the ependyma surface, which may affect different properties of the cerebrospinal fluid.

Adolescent↗

PubMed1986

Self-organization of ependyma in regenerating teleost spinal cord: evidence from serial section reconstructions.

Multiple ependymal structures have been observed in regenerating spinal cord of the teleost Apteronotus albifrons. Evidence is presented for two modes of formation of the secondary ependymas: budding off from the primary ependyma, and de novo origin of a tube-like ependymal structure within a group of undifferentiated cells. Serial sections of regenerated cord provide evidence that undifferentiated cells not in immediate contact with the main ependymal layer can organize and differentiate into an ependymal structure in the regenerating spinal cord. These findings suggest that a significant amount of morphological organization can take place independent of the normal developmental sequence and environment.

Animals↗

PubMedDate not supplied

[Incorporation of 3H-estradiol into elements of the tanycytic and ciliated ependyma of the 3d cerebral ventricle in experiments in vitro].

The label incorporation into the arcuate nucleus neurons, the tanicytic and ciliary ependyma of the mediobasal hypotahalamus, and also into the underlying nerve tissue after in vitro incubation of male Wistar rats hypothalamic tissue in the presence of 3H-estradiol was studied autoradiographically. After incubation at 37 degrees C, along with the nuclear localization of the label in the neutrons of the arcuate nucleus, characteristic of estradiol, high radioactivity was revealed in tanicytes; the label incorporation into beta-tanicytes was always higher than into the alpha2-tanicytes. Subsequent incubation of the tissue with nonlabeled estradiol led to reduction of beta-tanicytes radioactivity; as to ciliary ependyma and alpha2-tanicytes radioactivity--it rose. Reduction of incubation temperature to 22 degrees C failed to alter the character of the label incorporation into tanicytes. The data obtained confirmed the possibility of participation of the mediobasal hypothalamus tanicytes in the realization of the estradiol action of the hypothalamus.

Animals↗

PubMed1979

Melanosis of the choroid plexus, ependyma, subependymal neuroglia, and dentate and trigeminal motor nuclei: observations on the choroidal and ependymal cilia.

Melanosis of the choroid plexus, ependyma, subependymal neuroglia of the fourth ventricle, and dentate and trigeminal motor nuclei was found in a 50-year-old man who died with cor pulmonale, hypertensive cardiovascular disease, and intracerebral hemorrhage. This case is the first known example of melanosis not associated with neurocutaneous melanosis to involve multiple structures of the brain. Nonenzymatic conversion of lipofuscin into melanin is suggested as the mechanism of the melanosis. Cilia of the choroidal epithelium and ependyma were identified in this case, despite a long delay in postmortem examination. These observations on choroidal epithelium confirm previous reports that the choroid plexus of man is ciliated, as in other mammals and lower vertebrates.

Brain Diseases, Metabolic↗

PubMed1984

[Age-related changes in the ependyma and epithelium of the vascular plexuses of the cerebral ventricles].

Using scanning electron microscopy, the author studied the ependyma and epithelium of the vascular plexuses of the cerebral ventricles in young and old Wistar rats. The old animals presented considerable morphological changes of these structures which were expressed in the polymorphism of the surface of the vascular plexus epithelial cells and the expansion of the contact zones between them. The age-related alterations of the ependyma were characterized by the loss of cilia in some cells and the formation of considerable areas free of cilia on the luminal surface of the ventricle. These alterations may be essential for the age-related disorders of various functions of these structures.

Aging↗

PubMed1983

[Autoradiographic study of the proliferative activity of the preoptic recess ependyma in yearling and juvenile common frogs].

Proliferative activity of the ependyma, lining the recessus praeopticus in juvenile frogs was studied with 3H-thymidine radioautography. Usually much more pronounced proliferation of ependymal cells occurred in the preoptic region in one year old frogs as compared with two year old ones. It can be concluded that in the former animals the migration of postmitotic labeled cells into the subependymal zone of the recessus preoptic area is significantly more intense. By the 30th day after multiple isotope injections some newly formed neurosecretory cells with labeled nuclei were found in the 1-5 cellular position of the recessus praeopticus subependymal zone. It is postulated that in juvenile frogs the ependyma of lateral wall of recessus praeopticus is probably a source ("cambium"), from which some young neurosecretory cells may originate.

Animals↗

PubMed1983

[Ependyma of Merino sheep following continuous irradiation].

The ependyma of the lateral and IIIrd cerebral chamber was studied in 2 to 3 a old Merino sheep in the period of physiological anestrus after continuous 60Co irradiation for 7 d with a total exposure of 6.7 Gy. Locally focuslike or disseminated increased numbers of ependymous cells were found. Metaplasia of the original cell type was observed in the infundibular region of the IIIrd chamber, in the recessus pinealis and on the habenula in hyperplastic foci. The PAS-reaction for mucopolysaccharides in the subependyma at different sites of the lateral and IIIrd cerebral chamber was decreased to being negative. After continuous irradiation, the ependyma showed greater injury in the median and caudal than in the rostral portion of both chambers examined.

Animals↗