室管膜和室管膜上超微结构

脑脊液是中枢神经系统的一种特殊内环境,又是全身体液系统的一部分。结合大量的动物实验和临床观察,有学者提出了由这种物质和信息交流所构成的一种特殊的信息交流网络—“脑-脑脊液神经体液回路”。本文对“脑-脑脊液神经体液回路”的主要结构基础—室管膜和室管膜上超微结构的形态学特点及功能进行综述。     

The production of cerebrospinal fluid in experimental communicating hydrocephalus

Summary Utilizing an atraumatic model to produce chronic hydrocephalus, CSF production was measured during and after development of communicating hydrocephalus. CSF volume production was significantly lower in animals with increased pressure. Animals with chronic hydrocephalus and normal pressures had abnormal CSF production. Diminished CSF production appears to offer a potential compensatory mechanism when CSF absorption is altered.     

Ependymal astrocytes in the frog cerebellum

We have examined the ependymal astrocytes of the frog cerebellar cortex in thin sections and freeze-fracture replicas. The somata border the fourth ventricle and give rise to basal processes whose daughter branches cross the molecular layer and terminate as subpial endfeet. Irregular lamellar appendages arise from the basal processes and their branches. In the molecular layer the appendages selectively ensheath apposed parallel fiber boutons and Purkinje cell dendritic spines. Other appendages ramify throughout the neuropil, some contributing to extensive pericapillary sheaths. Freeze-fractured ependymal astrocyte plasma membrane consistently has a greater concentration of intramembranous particles (IMPs) and IMPs of larger mean size than neuronal plasma membrane in the same replicas. Like the astrocytes of the mammalian central nervous system, frog ependymal astrocytes form numerous gap junctions with each other. However, orthogonal arrays of IMPs (“assemblies”) were not observed. Ependymal cells in the frog cerebellum combine the morphology, and probably the functions, of both ependymal cells and astrocytes.     

Ependymal variant of dysembryoplastic neuro-epithelial tumor

Dysembryoplastic neuro-epithelial tumors (DNET) are glioneuronal tumors with a common astrocytic or oligodendroglial differentiation. We report a case of DNET with an ependymal differentiation. A 13 years-old girl had refractory focal seizures for 3 years. Successive MRI showed a stable cortical lesion of the right temporal lobe with DNET characteristics. The lesion was resected. Histological examination revealed a pure ependymal differentiation characterized by perivascular pseudorosettes containing EMA immunoreactive cells. Mib1 positive cells were absent. In spite of histologic features of ependymoma, this tumor showed clinical, radiological and behaviour characteristics of DNET. We are not aware of any other case of DNET with ependymal differentiation in the literature. Our observation suggests that the glial component of DNET may show an ependymal differentiation.     

Ultrastructural changes in experimental tetanus

In experiments on rats an electron-microscopic study was undertaken of the caudal part of the hypothalamic-hypophyseal neurosecretory system in experimental tetanus. Activation of the system was found in the early stages after injection of tetanus toxin, evidently on account of the injection of heterologous protein, for a similar effect was given by injection of the inactivated toxin. Parallel changes were observed in vascular permeability, lipid metabolism, and the clotting system of the blood.Central Research Laboratory, Rostov Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 4, pp. 489–493, April, 1978.     

So-Called Glandular Schwannoma: Ependymal Differentiation in a Case

A cervical root tumor in a patient with neurofibromatosis showed a biphasic pattern of spindle and epithelioid cells with prominent “gland” formation, characteristic of the so-called glandular schwannoma. Electron microscopy and histochemistry of the “glands” disclosed features consistent with an ependymal differentiation. It is noted that there is a curious preferential association of ependymal lesions and neurofibromatosis, the pathogenesis of which is not understood.     

Neuropsychological changes following the neurosurgical treatment of normal pressure hydrocephalus

Extracranial shunting of cerebrospinal fluid is a well-known neurosurgical procedure for the treatment of normal pressure hydrocephalus. Research indicating reasonable success using this technique has been based primarily on subjective and global neurosurgical opinion. Given that the treatment carries morbidity risks, and that decisions to shunt are related to increasing adaptive functioning, attention must be paid to adequate measurement of surgical outcome. As part of a larger study, we report pre and postsurgical neuropsychological, neuroradiological, and clinical data on hydrocephalic patients, as well as presurgical intracranial pressure data. Prior to shunting, increase in ventricular dilatation and cerebral atrophy were associated with decreased cognitive functioning, gait disturbance, and bladder dysfunction. Following shunting, there were significant improvements in neuropsychological functioning in terms of attention, concentration, verbal and nonverbal memory, language and communication skills, and constructional skills, as well as clinical improvement in gait and bladder functioning. Improvement was related to presurgical dilatation of the temporal horns of the lateral ventricles and mental status, particularly memory functions.     

Morphological changes in experimental duodenogastric reflux

The model of a total duodenal-gastric reflux was developed in 20 dogs and morphological changes in the stomach were studied. 5 dogs served as control. Histologic changes occurred 3.5 months and 1 year after the operation were characterized by metachromasia, increased mucus formation, proliferation of epithelial and parietal cells, moderate inflammation. Process of the disease had fluctuations. 6 months after the operation 5 dogs were reoperated for the elimination of reflux and were observed for another 6 months. A complete reversibility of all changes was established. Bacteriological studies showed a considerable increase of bacteria population in the stomach and a pH increase. The authors suggest the term 'reflux gastropathy" to replace the term "alkaline reflux-gastritis".     

Detection of differentiated changes in gray matter in children with progressive hydrocephalus and chronic compensated hydrocephalus using voxel-based morphometry and machine learning

Currently, no neuroimaging study has reported the detection of specific imaging biomarkers that distinguish the progressive hydrocephalus (PH) and chronic compensated hydrocephalus (CH). Our main focus is to evaluate the different structural changes in classifying the two types of hydrocephalus children. Twenty-two children with hydrocephalus (12 PHs and 10 CHs) and 30 age-matched healthy controls were enrolled and the T1-weighted imaging was collected in the study. A customized voxel-based morphometry (VBM) approach and support vector machine (SVM) were combined to investigate the structural changes and group classification. Comparing with the controls and CH, PH groups invariably showed a significant decrease of GM volume in the bilateral hippocampus/parahippocampus, insula, and motor-related areas. SVM applied to the GM volumes of bilateral hippocampus/parahippocampus, insula, and motor-related areas correctly identified hydrocephalus children from normal controls with a statistically significant accuracy of 88.46% (p ≤ .001). In addition, SVM applied to GM volumes of the same regions correctly identified PH from CH with a statistically significant accuracy of 77.27% (p ≤ .009). Using VBM analysis, we characterized and visualized the GM changes in children with hydrocephalus. Machine learning results further confirmed that a significant decrease of the bilateral hippocampus/parahippocampus, insula, and motor-related GM volume can serve as a specific neuroimaging index to distinguish the children with PH from the children with CH and controls at individual. The findings could help to aid the identification of individuals with PH in clinical practice.     

Morphological changes in experimental amyotrophic leukospongiosis

A new nosological entity of slow infections provoked by noncanonical viruses was experimentally studied. It was shown that natural human infection and infection induced in guinea pigs had common clinical and morphological parameters and were characterized by severe changes in the central nervous system. Histologically, the death of the motoneurones of the spinal cord, the spongious state of the white matter of the brain and spinal cord, relative preservation of myelin, hypertrophy and proliferation of macroglia were histologically observed.     

Early changes in experimental allergic neuritis

Edema and increased endoneurial fluid pressure (EFP) accompany the inflammatory process in experimental allergic neuritis. EFP was measured at regular intervals 6 to 21 days after intradermal inoculation of Lewis rats with an emulsion of peripheral nerve in complete Freund's adjuvant. Control rats received similar injections of an emulsion containing all other ingredients, except peripheral nerve. Altered vascular permeability was illustrated by leakage of horseradish peroxidase into rat sciatic nerve endoneurial space as early as 10 days after inoculation. A difference in EFP between controls and test animals became apparent after 11 days, and highest values were obtained 12 to 16 days postinoculation. Nerves were excised for histologic examination after EFP measurement. Severe endoneurial edema was present after 12 days and was associated with appreciable inflammatory cell infiltration. Inflammatory cells were clustered around small vessels and also were numerous in the subperineurial space which was expanded by edema. Degranulation of mast cells was also noted in association with edema and inflammation. Immunoperoxidase staining revealed immunoglobulin in the subperineurial and perivascular spaces 10 to 12 days postinoculation, but not in sections 6 to 9 days (postinoculation). These findings suggest suggest that altered vascular permeability is the earliest morphologic change in experimental allergic neuritis, followed by accumulation of antibody-containing edema fluid, penetration of the endoneurium by inflammatory cells, and increased EFP.