Tomografía computada y resonancia magnética de variantes normales/congénitas de apariencia quística y presentación frecuente en el encéfalo / CT and MRI of Normal/Congenital Variables with Cystic Appearance and Frequent Presence in the Brain

La presentación de una imagen de apariencia quística durante el estudio del encéfalo constituye un hallazgo incidental cada vez más frecuente, pudiendo encontrarse en el espacio extra o intraaxial. Las mismas pueden ser de naturaleza congénita o adquirida, benigna o maligna, ocupantes de espacio con desplazamiento de la línea media o simplemente presentarse sin efecto compresivo alguno. De localización supra o infratentorial, esas imágenes constituyen un desafío diagnóstico, siendo imprescindible su reconocimiento para no solicitar estudios o tratamientos innecesarios. Valoraremos las imágenes de apariencia quística más frecuentes empleando tomografía computada o imágenes de resonancia magnética.

Presence of a cystic formation in brain examination is frequently an incidental finding. They can be intra or extra-axial in location, congenital or acquired, benign or malignant with or without mass effect. Intracranial cysts can be a diagnostic challenge and we should know them to avoid unnecessary exams or treatment. We will analyze the most common cystic formations seen in computed tomography and magnetic resonance.

Inactivation of Cdc42 in embryonic brain results in hydrocephalus with ependymal cell defects in mice

The establishment of a polarized cellular morphology is essential for a variety of processes including neural tube morphogenesis and the development of the brain. Cdc42 is a Ras-related GTPase that plays an essential role in controlling cell polarity through the regulation of the actin and microtubule cytoskeleton architecture. Previous studies have shown that Cdc42 plays an indispensable role in telencephalon development in earlier embryo developmental stage (before E12.5). However, the functions of Cdc42 in other parts of brain in later embryo developmental stage or in adult brain remain unclear. Thus, in order to address the role of Cdc42 in the whole brain in later embryo developmental stage or in adulthood, we used Cre/loxP technology to generate two lines of tissue-specific Cdc42-knock-out mice. Inactivation of Cdc42 was achieved in neuroepithelial cells by crossing Cdc42/ flox mice with Nestin-Cre mice and resulted in hydrocephalus, causing death to occur within the postnatal stage. Histological analyses of the brains from these mice showed that ependymal cell differentiation was disrupted, resulting in aqueductal stenosis. Deletion of Cdc42 in the cerebral cortex also induced obvious defects in interkinetic nuclear migration and hypoplasia. To further explore the role of Cdc42 in adult mice brain, we examined the effects of knocking-out Cdc42 in radial glial cells by crossing Cdc42/flox mice with human glial fibrillary acidic protein (GFAP)-Cre mice. Inactivation of Cdc42 in radial glial cells resulted in hydrocephalus and ependymal cell denudation. Taken together, these results highlight the importance of Cdc42 for ependymal cell differentiation and maintaining, and suggest that these functions likely contribute to the essential roles played by Cdc42 in the development of the brain.

The long-term dynamic changes of proliferation and differentiation of neural stem cells in subventricular zone and dentate gyrus of vascular dementia rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To observe the dynamic changes of proliferation and differentiation of neural stem cells (NSCs) in subventricular zone (SVZ) and dentate gyrus (DG) in vascular dementia (VD) rats.</p><p><b>METHODS</b>VD models were established by repeatedly clipping the common carotid arteries of the rat in combination with an intraperitoneal injection of sodium nitroprusside solution in anesthetized SD rats. Morris maze test was used to detect the learning and memory ability of the rats and immune fluorescence single and double labeling method to detect the proliferation and differentiation of neural stem cells and the expression of neurogranin (Ng) at 15 d, 1 month, 2 month, 4 month time points.</p><p><b>RESULTS</b>Compared with sham-operated group, the escape latency of model group rats were significantly longer at all the time points (P < 0.01). The BrdU positive cells in SVZ and DG of VD model groups were markedly increased in comparison with sham-operated group at 15 d and 1 month time point (P < 0.01), and the number of BrdU positive cells in SVZ of model groups were still larger than that of sham-operated group at 2 month and 4 month time point (P < 0.01). In model group, the number of the BrdU/Ng double staining cells were increased and higher than that in sham-operated groups (P < 0.05).</p><p><b>CONCLUSION</b>The proliferation of NSCs can be enhanced noticeably in a certain time in SVZ and DG region and NSCs differentiate into mature neurons with the expression of Ng in DG region in VD rats, which may play some compensatory roles in the nerve regeneration and functional repairmen after cerebral injury of VD.</p>

Valproic Acid Increases Expression of Neuronal Stem/Progenitor Cell in Spinal Cord Injury

OBJECTIVE: This study investigates the effect of valproic acid (VPA) on expression of neural stem/progenitor cells (NSPCs) in a rat spinal cord injury (SCI) model. METHODS: Adult male rats (n=24) were randomly and blindly allocated into three groups. Laminectomy at T9 was performed in all three groups. In group 1 (sham), only laminectomy was performed. In group 2 (SCI-VPA), the animals received a dose of 200 mg/kg of VPA. In group 3 (SCI-saline), animals received 1.0 mL of the saline vehicle solution. A modified aneurysm clip with a closing force of 30 grams was applied extradurally around the spinal cord at T9, and then rapidly released with cord compression persisting for 2 minutes. The rats were sacrificed and the spinal cord were collected one week after SCI. Immunohistochemistry (IHC) and western blotting sample were obtained from 5 mm rostral region to the lesion and prepared. We analyzed the nestin immunoreactivity from the white matter of ventral cord and the ependyma of central canal. Nestin and SOX2 were used for markers for NSPCs and analyzed by IHC and western blotting, respectively. RESULTS: Nestin and SOX2 were expressed significantly in the SCI groups but not in the sham group. Comparing SCI groups, nestin and SOX2 expression were much stronger in SCI-VPA group than in SCI-saline group. CONCLUSION: Nestin and SOX2 as markers for NSPCs showed increased expression in SCI-VPA group in comparison with SCI-saline group. This result suggests VPA increases expression of spinal NSPCs in SCI.

Expression of transient receptor potential channels in the ependymal cells of the developing rat brain / 대한해부학회지

Cerebrospinal fluid (CSF) plays an important role in providing brain tissue with a stable internal environment as well as in absorbing mechanical and thermal stresses. From its initial composition, derived from the amniotic fluid trapped by the closure of neuropores, CSF is modified by developing and differentiating ependymal cells lining the ventricular surface or forming the choroid plexus. Its osmolarity and ionic composition brings about a change through the action of many channels expressed on the ependymal cells. Some newly discovered transient receptor potential (TRP) channels are known to be expressed in the choroid plexus ependyma. To detect additional TRP channel expression, immunohistochemical screening was performed at the choroid plexus of 13-, 15-, 17-, and 19-day embryos, using antibodies against TRPV1, TRPV3, and TRPA1, and the expression was compared with those in the adult TRP channels. The level of TRP channel expression was higher in the choroid plexus which suggests more active functioning of TRP channels in the developing choroid plexus than the ventricular lining ependyma in the 15- and 17-day embryos. All the expression of TRP channels decreased at the 19th day of gestation. TRPA1 was expressed at a higher level than TRPV1 and TRPV3 in almost all stages in both the choroid plexus and ventricular lining epithelium. The highest level of TRPV1 and TRPV3 expression was observed in association with the glycogen deposits in the cytoplasm of the choroid plexus ependymal cells of the 15- and 17-day embryos.

Quiste glioependimario congenito: reporte de caso / Glioependymal congenital cyst: case report

El Quiste Glioependimario es un tumor extremadamente raro y excepcionalmente pocos casos han sido reportados; se caracterizan por una cavidad cerrada, con una capa de tejido de epitelio ependimario o una mezcla de tejido ependimario y epitelio coloideo, con un lumen relleno por líquido cefalorraquídeo. Presentamos el caso de un paciente manejado en el servicio de neurocirugía de la Universidad de Cartagena con esta patología.

Spinal intramedullary neuroepithelial (ependymal) cyst. A rare cause of treatable acute para paresis.

An 8-yr-old female child presented with acute onset of severe pain in the lower limbs and difficulty in walking. Spine MRI showed hyperintense signals on T2 weighted images at T2-T3 level, which was intramedullary in location. The patient was operated and histopathology reported as neuroepithelial cyst. Spinal intramedullary neuroepithelial cysts are rare. Spinal cord compression due to the cyst is very uncommon and because of its rarity the present case is being reported. The clinical features, embryogenesis and literature were reviewed briefly.

Tuberous sclerosis: Report of two cases diagnosed by computer assisted cranial tomography without cutaneous manifestations

We represent two patients suffering from tuberous sclerosis without cutaneous manifestations Both were diagnosed on cranial CT scan. Both had typical calcified ependymal lesions. Our first patient had bilateral renal angiomyolipomas as well. Second patient had typical calcified ependymal lesions near foraman of Monro and calcified left cerebella tubers

Magnetic resonance imaging determination of the ventriculus terminalis

We report a case of ventriculus terminalis, presenting with specific neurological symptoms including low back pain and bilateral sciatica. Magnetic resonance images showed a cystic lesion with regular margins localized in the lumbar enlargement of the spinal cord. The lesion was an oval shape with no internal septa. Its dimensions were 9.6 mm craniocaudally, 3.5 mm mediolaterally and 3.5 mm anteroposteriorly. Intralesional fluid had the same signal as cerebrospinal fluid in all magnetic resonance sequences. Pericystic spinal cord intensity was normal, and the cyst did not cause additional enlargement of the distal cord. During spinal cord evaluations, ventriculus terminalis should be kept in mind as a normal anatomic developmental phenomenon that can be seen on magnetic resonance images

The lizard cerebral cortex as a model to study neuronal regeneration

The medial cerebral cortex of lizards, an area homologous to the hippocampal fascia dentata, shows delayed postnatal neurogenesis, i.e., cells in the medial cortex ependyma proliferate and give rise to immature neurons, which migrate to the cell layer. There, recruited neurons differentiate and give rise to zinc containing axons directed to the rest of cortical areas, thus resulting in a continuous growth of the medial cortex and its zinc-enriched axonal projection. This happens along the lizard life span, even in adult lizards, thus allowing one of their most important characteristics: neuronal regeneration. Experiments in our laboratory have shown that chemical lesion of the medial cortex (affecting up to 95 percent of its neurons) results in a cascade of events: first, massive neuronal death and axonal-dendritic retraction and, secondly, triggered ependymal-neuroblast proliferation and subsequent neo-histogenesis and regeneration of an almost new medial cortex, indistinguishable from a normal undamaged one. This is the only case to our knowledge of the regeneration of an amniote central nervous centre by new neuron production and neo-histogenesis. Thus the lizard cerebral cortex is a good model to study neuronal regeneration and the complex factors that regulate its neurogenetic, migratory and neo-synaptogenetic events

Nestin expression and proliferation of ependymal cells in adult rat spinal cord after injury / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To determine cell proliferation and nestin expression in the ependyma of adult rat spinal cord after injury.</p><p><b>METHODS</b>Rat spinal cord injury models were established by aneurysm clip compression, and nestin expression and proliferation of ependymal cells at different times were shown with pathological and immuno-histochemical staining.</p><p><b>RESULTS</b>Ependymal cells adjacent to the injured site demonstrated a dramatic increase in nestin expression 24 hours after compression. Proliferating cell nuclear antigen was positive, and significant proliferation was observed after 7 days. Nestin expression was down regulated as time went by.</p><p><b>CONCLUSION</b>Normally quiescent mature ependymal cells appear to revert to an embryonic state in response to spinal cord injury.</p>

Developmental Changes of Glial Fibrillary Acidic Protein (GFAP) and Proliferating Cell Nuclear Antigen (PCNA) Immunoreactivity of the Ependyma lining the Central Canal and Ventriculus Terminalis in the Human Fetus / 대한해부학회지

The distinguishing morphological features of the ependyma lining ventriculus terminalis in human fetus have suggested that its differentiation would be somewhat delayed or arrested as compared with the ependyma lining central canal. To demonstrate this hypothesis, GFAP was used as a marker to compare the developmental state of the ependyma lining ventriculus terminalis and central canal along fetal age (18 -to 24 -week -old fetuses were investigat-ed). PCNA was also used as a marker to identify whether proliferation potentiality of the ependyma lining ventriculus terminalis lasted longer than that of the ependyma lining central canal as a result of differentiation delay. GFAP -positive ependymal cells were restricted to dorsal plate at central canal but at ventriculus terminalis, many positive cells were identified in all regions compared with the ependyma lining central canal. The number of PCNA -positive ependymal cells lining central canal decreased sharply about the time of 20th week, but at ventriculus terminalis, many ependymal cells continued to express PCNA after 20th week. As a result, we could conclude that differentiation of the ependyma lining ventriculus terminalis is delayed as compared with the ependyma lining central canal. In accordance with its developmental delay, it lasts longer proliferation potentiality than the ependyma lining central canal.

Cavernomas del tronco cerebral: aspectos clínicos y terapéuticos: experiencia personal de tres casos y revisión de la literatura / Cavernoma in the brain stem: clinical and therapeutical aspects: personal experience in 3 cases and a review of literature

Los avances que se han producido en los últimos años, con la introducción de la Resonancia Nuclear Magnética, han permitido conocer la verdadera frecuencia de los cavernomas cerebrales, acercando esta cifra a las publicadas de los estudios de autopsia y que se acepta alrededor del 0,4 por ciento. Así mismo, este avance ha permitido conocer en gran medida su historia natural obteniendo información acerca de sus formas de presentación clínica como el riesgo de hemorragia, la cual se ha constituido en el principal elemento de sostén del tratamiento quirúrgico. Actualmente se estima que este riesgo varía entre un 0,25 por ciento a 1,6 por ciento al año, el cual se ve claramente aumentando en las lesiones de fosa posterior en las que aumenta cerca de treinta veces. De acuerdo a las publicaciones se considera que el tratamiento quirúrgico esta claramente indicado en aquellas lesiones de fosa posterior y en especial si han presentado un episodio de hemorragia previamente. En esta publicación se presentan tres casos personales de cavernomas de tronco cerebral, que presentaron previamente fenómenos hemorrágicos. Los tres pacientes fueron intervenidos quirúrgicamente, obteniéndose la remoción completa de la lesión y de un componente angiomatoso asociado en dos de ellos. El curso postoperatorio en los tres casos ha sido excelente, regresando a sus actividades normales y sin limitaciones, con regresión completaa de sus síntomas y signos preoperatorios

Tecido cerebral ectópico na órbita: relato de dois casos / Ectopic brain tissue in the orbit: two case report

Tecido cerebral na órbita, tendo continuidade com o conteúdo intracraniano, é relativamente incomum. Tecido cerebral isolado na órbita, entretanto, é muito mais raro. No presente trabalho säo apresentados dois casos de tecido cerebral ectópico na órbita, com cisto ependimal. Säo analisadas as similaridades e diferenças com outros casos da literatura, bem como as dificuldades no diagnóstico desta malformaçäo. Näo conhecemos nenhum caso descrito na literatura nacional.

Morphological Study of the Ventriculus Terminalis in the Human Fetal Spinal Cord / 대한해부학회지

The ventriculus terminalis, also known as the 'fifth ventricle', is a dilated cavity in the conus medullaris. It is formed by degenerative process in the course of neural tube development, but the definite function is unclear. And the reports, which have studied the morphological variation according to fetal age, are insufficient. So, in this report, we observed the morphological variation of the ventriculus terminalis and measured the areal ratio of the ventriculus terminalis to the parenchyma of conus medullaris by fetal age. We also studied the fine structure of the conus medullaris and ependyma by electron microscope. The ventriculus terminalis began at the level at which the ependymal cells proliferated and the central canal moved to the dorsal region. Periependymal islet was observed at this level. At the lower level, it immediately extended both lateral sides and finally switched over to the filum terminale. The area ratio of the ventriculus terminalis to the parenchyma of the conus medullaris increased from above downward. Especially, It increased steeply between the Leaf-shaped region and the transitional zone, where the ventriculus terminalis began. But the increasing pattern was too irregular to generalize its pattern by fetal age. The ependyma lining the ventriculus terminalis was composed of pseudostratified ciliated columnar epithelium layer about 5~7 cells thick. It had conspicuous intercellular junctional complexes close to the lumen into which microvilli and cilia projected. At the junction where the ependyma meets the parenchyma of the conus medullaris, we could observe many myelin-like structures made by basolateral membrane of the ependymal cell. In the conus medullaris, we could observe many obscure cell types because they were in the course of differentiation. On the other hand, we could also observe the fully differentiated nerve cells, astrocytes and oligodendrocytes which seemed to play its own role. A lot of developing myelin sheaths were observed and the majority was the degenerative one. Some ependymal cells showed the apoptotic characteristics and many cell debris were observed in the lumen. As a result, the ventriculus terminalis was formed by the combination of cell differentiation and degeneration, and its development was independent of the spinal cord.

Serotonergic ependymal fibres in rat and monkey: light and electron microscopic immunocytochemical study

The distribution of serotonin (5HT) immunoreactive fibres in the ependymal epithelium of aqueductus cerebri in adult rat and monkey was studied by means of immunocytochemical methods using specific antibodies against 5HT. Light microscopic examination of immunostained coronal sections of mesencephalon showed, in tryptophan and pargylin pretreated animals, abundant serotonergic fibres distributed along the ependymal cells of the aqueduct, forming supraependymal and subependymal plexi. Serotonin fibres lying either supraependymally or ending freely in the aqueduct lumen contributed to the formation of a rich 5HT containing network on the ependymal surface. Electron microscope images showed dense 5HT-immunoreactive (5HT-IR) profiles with ultrastructural characteristics of axon terminals ending on the ependymal cells. Dense diaminobenzidine (DAB) deposits were found in the axoplasm, on outer mitochondrial surface and in vesicles. No synaptic contacts were observed between 5HT-IR terminals and ependymal cells. Unstained microvilli and cilia were also observed in the aqueduct lumen. Serotonin immunoreactivity disappeared from ependymal fibres in animals treated with parachlorophenylalanine, an inhibitor of 5HT synthesis. 5HT containing fibres described in this paper may be the source of 5HT and its metabolite 5-hydroxyindoleacetic acid (5HIAA) found in cerebrospinal fluid (CSF) and of clinical relevance in some psychiatric conditions such as depression, suicidal attempts, etc

Neuromielitis óptica: una enfermedad necrotizante del sistema nervioso central / Optic neuromyelitis: a necrotizing disease of the central nervous system

Optic neuromyelitis is characterized by simultaneous or successive necrotizing lesions involving the optic nerves and the spinal cord. We report two females with the disease, aged 30 and 34 years old. In the latter, a neuropathological study was done. Both patients had clinical, neuroradiological and pathological features that differed from those of primary demyelinating syndromes such as multiple sclerosis. These patients illustrate the selectivity of optic nerve and spinal cord lesions. The latter involve mainly pyramidal and Goll tracts while, within the necrotizing lesions of the optic chiasma, the fibers of the unaffected optic nerve are spared. This pattern suggests a selective injury to some population of axons. Blood vessels were not affected in the necrotizing areas and the lesions did not follow a vascular territory, therefore a vascular mechanism causing the disease is unlikely. The clinical and neuropathological features of neuromyelitis optic suggest a selective involvement of some axons

Symptomatic Isolated IV Ventricular Hydrocephalus in Adults: Clinical Diagnosis and Management of Five Cases

Isolated fourth(IV) ventricle in shunted patients has been reported with increasing frequency. Symptomatic isolated IV ventricular hydrocephalus in adults, however, has seldom been described. We report five such cases among total of 420 shunted cases in our institution from January 1992 to December 1995. The causes of initial hydrocephalus were postsurgical meningitis(SAH, teratoma and abscess of posterior fossa), tuberculous meningitis and neurocysticercosis of the IV ventricle. All cases were symptomatic with clinical findings related to posterior fossa lesions. Two patients developd symptoms in 2 months after V-P shunts and the others between 17 and 118 months after V-P shunts. These 5 patients required IV ventricular shunting. All patients improve postoperatively except one patient who developed 6th nerve palsy related to secondary irritation of the brainstem by the IV ventricular catheter. Inflammatory changes in the ependyma of both aqueduct of Sylvius, foramina Luschka and Magendi have been regarded as the most important factors in the development of the isolation of IV ventricle, especially in adults. It is generally recommended to shunt in cases of the adult symptomatic isolated IV ventricle. Alternative surgical techniques and prevention of such complications are discussed.

Malformaciones congénitas del sistema nervioso / Congenital malformations of nervous system

Se presenta la incidencia de las malformaciones congénitas del sistema nervioso diagnosticadas al examinar 5832 recién nacidos vivos en la maternidad del hospital "Jaime Mendoza" C.N.S. de Sucre, en el período comprendido entre Julio de 1997. Se hace una revisión actualizada de embriología del sistema nervioso y se las agrupa de acuerdo a la Clasificación Internacional de Enfermedades de la OMS