Atypical extraventricular neurocytoma: A case report.

Atypical extraventricular neurocytoma (EVN) is a rare condition characterized by diffuse tumor cell hyperplasia, increased neovascularization, increased necrosis, and aggressive characteristics. A case of a 25-year old man who presented with atypical EVN in his left parietal - occipital flaps is reported. Magnetic resonance imaging (MRI) revealed a well-defined globular mass with heterogeneous signals in the left parietal lobe, and mild perilesional edema. After left parietal craniotomy and tumor excision, pathologic examination of the resected tissue revealed that the lesion was localized mainly in the white matter and imbued with tumor cells possessing round hyperchromatic nuclei with perinuclear halos and increased microvascular proliferation. The patient underwent radiotherapy at 21st postoperative day. Over the past 26 months, the patient has been regularly followed up, and so far no neurologic deficits have been observed. The latest MRI showed that the tumor bed was stable with slight peritumoral edema. The results of clinical, histopathological and immunohistochemical examinations indicate that atypical EVN is a rare neoplasm with unique radiographic and pathologic characteristics. It possesses more aggressive properties than typical EVN.

Endoscopic biopsy of a B-cell lymphoma involving the entire ventricular system: A case report.

A 62-year-old male suffering from vomiting and mild preceding nausea for 15 days was examined in the present case report. Magnetic resonance imaging revealed a homogeneously enhancing cluster-like lesion involving the lateral, third and fourth ventricles. An endoscopic biopsy was performed, and histopathological examination led to the diagnosis of a high-grade diffuse large B-cell lymphoma. To the best of our knowledge, the present study reports the first case of a primary lymphoma involving the entire ventricular system. Therefore, primary lymphomas should be considered in the list of ventricular tumors. An endoscopic biopsy requires minimal invasion to obtain an adequate tissue sample, and frequently leads to the correct diagnosis and subsequent treatment protocols.

Hyperactive external awareness against hypoactive internal awareness in disorders of consciousness using resting-state functional MRI: highlighting the involvement of visuo-motor modulation.

Resting-state functional MRI (fMRI) has emerged as a valuable tool to characterize the complex states encompassing disorders of consciousness (DOC). Awareness appears to comprise two coexistent, anticorrelated components named the external and internal awareness networks. The present study hypothesizes that DOC interrupts the balance between the internal and external awareness networks. To gain more understanding of this phenomenon, the present study analyzed resting-state fMRI data from 12 patients with DOC versus 12 healthy age-matched controls. The data were explored using independent component analysis and amplitude of low-frequency fluctuation (ALFF) analysis. The results indicated that DOC deactivated midline areas associated with internal awareness. In addition, external awareness was strengthened in DOC because of increased activation in the insula, lingual gyrus, paracentral and supplementary motor area. The activity patterns suggested strengthened external awareness against weakened internal awareness in DOC. In particular, increased activity found in the insula, lingual gyrus, paracentral and supplementary motor area of patients with DOC implied possible involvement of augmented visuo-motor modulation in these patients. DOC is probably related to hyperactive external awareness opposing hypoactive internal awareness. This unique pattern of brain activity may potentially be a prognostic marker for DOC.

Potassium channels underlie postsynaptic but not presynaptic GABAB receptor-mediated inhibition on ventrolateral periaqueductal gray neurons.

γ-Aminobutyric acid (GABA) is the principle inhibitory neurotransmitter in adult mammalian brain. GABA receptors B subtype (GABA(B)Rs) are abundantly expressed at presynaptic and postsynaptic neuronal structures in the rat ventrolateral periaqueductal gray (PAG), an area related to pain regulation. Activation of GABA(B)Rs by baclofen, a selective agonist, induces presynaptic inhibition by decreasing presynaptic glutamate release. At the same time, baclofen induces a postsynaptic inhibitory membrane current or potential. We here report that in the ventrolateral PAG, the postsynaptic inhibition is mediated by activation of G protein-coupled inwardly rectifying K(+) (GIRK) channels. Blockade of K(+) channels largely prevents postsynaptic action of baclofen. In contrast, presynaptic inhibition of baclofen is insensitive to K(+) channel blockade. The data indicate that potassium channels play different roles in GABA(B)R-mediated presynaptic and postsynaptic inhibition on PAG neurons.

Neural stem cells differentiation ability of human umbilical cord mesenchymal stromal cells is not altered by cryopreservation.

Human umbilical mesenchymal stem cells (HUMSCs) have potential therapeutic use in the recovery of central nervous system injury for their ability to differentiate into neural stem cells. However, for transformed HUMSCs to be constantly available for use during surgery a reliable method of cell storage is necessary. The present study aimed to determine whether a simple method of cryopreservation by slow cooling with Me(2)SO had an effect on the proliferation, secretion and differentiation capacities of HUMSCs. These results demonstrate that cryopreservation has no effect on the phenotype, cell cycle, cell proliferation and the ability to secret neurotrophins. Non-cryopreserved and cryopreserved HUMSCs showed the similar ability to differentiate into neural stem-like cells. There results show that cryopreservation by slow cooling with Me(2)SO is effective to retain the proliferation and neural differentiation ability of HUMSCs, cryopreserved HUMSCs maybe very useful for future clinical applications in neural regenerative medicine.

Differentiation of cryopreserved human umbilical cord blood-derived stromal cells into cells with an oligodendrocyte phenotype.

In this study, we examined the phenotypic characteristics of human umbilical cord blood-derived mesenchymal stromal cells (UCB-derived MSCs) differentiated along an oligodendrocyte pathway. We induced human UCB-derived MSCs to form floating neurospheres, and these neurospheres were then induced to differentiate into oligodendrocyte progenitor-like cells using multiple induction factors. Differentiated UCB-derived MSCs showed morphologic characteristics of an oligodendrocyte phenotype. The expression of cell surface markers characteristic of oligodendrocyte progenitor cells or oligodendrocytes was determined by immunocytochemical staining. These results suggest that human UCB-derived MSCs can be induced to differentiate into cells with an oligodendrocyte phenotype and that these cells may have potential in the future cellular therapy of central neurological disorders.

[Responses of neurons and astrocytes in rat hippocampus to kainic acid-induced seizures].

OBJECTIVE: To investigate the time course of the responses of neurons and astrocytes in rat hippocampus (HI) to kainic acid (KA)-induced seizures in various regions. METHODS: By means immunohistochemical staining for anti-Fos protein and anti-glial fibrillary acidic protein (GFAP), the regional distribution of reactive neurons and astrocytes in the HI was observed at different time points after a unilateral stereotaxic microinjection of KA into the lateral ventricle of rats to cause limbic and generalized convulsive seizures. RESULTS: The injection of KA triggered limbic motor seizures including immobilization, staring, facial and jaw clonus ect. followed by recurrent generalized convulsive seizures. After KA-induced seizures, the GFAP-positive astrocytes and Fos-positive neurons were markedly increased in the HI. The increase of GFAP immunoreactivity was observed 30 min after the seizure onset, reaching the maximum at 1 h; the increase of Fos immunoreactivity was detected at 1 h after the onset, peaking at 2 h. CONCLUSION: The neurons and astrocytes in rat HI are highly active during seizures and the reactive astrocytes might play an important role in epileptogenesis.