Pelizaeus-Merzbacher disease with thiamine deficiency or Leigh disease with extensive involvement of white matter? Case report.

We report on a case of a 30-month-old child who presented with a clinical syndrome compatible with leucodystrophy and in whom neuropathological features of both Pelizaeus-Merzbacher disease and subacute necrotizing encephalopathy were shown. The significance of the neuropathological findings is discussed in the light of a possible coexistence of both diseases which has not previously been reported.

[High extracellular concentrations of potassium and rubidium modulate the synaptic transmission in the frog labyrinth].

High extracellular K or Rb levels (20 mM) produce an increase in the resting EPSP and spike frequencies recorded intra cellularly from single fibres of the posterior nerve in the isolated frog labyrinth. The afferent discharge facilitation proved to be inversely related to the fibre's initial resting activity. The K effect is systematically larger than the Rb effect.

High perilymphatic potassium and rubidium levels modulate the sensory resting discharge in the isolated frog labyrinth.

The effects of high perilymphatic K+ and Rb+ concentrations (20 mM) on the posterior canal resting discharge have been examined in the isolated frog labyrinth. Both K+ and Rb+ produced an increase in spike frequency which is sustained by a parallel increase in the excitatory postsynaptic potential (EPSP) emission rate. High K+ and Rb+ levels reduce the size of the afferent spike, broaden its time course but do not induce repetitive activity at the axon level.

An immunohistological study of 66 ependymomas.

Sixty-six ependymomas were examined immunohistologically to determine their distribution of glial fibrillary acidic proteins, S-100 protein and vimentin. The neoplasms were subdivided into four groups: (1) ependymomas from the cauda equina, predominantly of the myxopapillary type; (2) benign ependymomas; (3) malignant ependymomas; and (4) ependymoblastomas. Marked differences in antigen reactivity were observed between each group.

Histologic characterization of 41 ependymomas with the help of a personal computer.

Fourty-one ependymomas were histologically analyzed in relation to patient age and sex and tumor location. A discriminant analysis model using Bayes' formula and a personal computer were employed. Ependymomas situated in the posterior fossa had a higher incidence in children.

The effect of barium and some channel blockers on sensory discharge of the frog labyrinth posterior canal recorded at rest and during rotation.

The effect on the afferent synaptic transmission of Ba2+, Sr2+, tetraethylammonium (TEA) and 4-aminopyridine (4-AP) has been investigated in the isolated frog labyrinth by intracellularly recording the posterior canal resting and evoked receptor discharge. BaCl2 (0.3 mM) or SrCl2 (1.

Epithelial membrane antigen expression in ependymomas.

Twenty-seven ependymomas were studied (18 'benign' or low grade and nine 'malignant' or high grade) by means of a monoclonal antibody to epithelial membrane antigen (E29) and an antiserum to glial fibrillary acidic protein (GFAP). The E29 antibody reacted with 'benign' ependymomas but not with 'malignant' ones. Staining was located on the cell surface and especially that facing rosette lumina.

Immunocytochemical study of the cellular immune response in meningiomas.

Twenty four meningiomas (17 benign and seven "atypical" were reacted with a panel of monoclonal antibodies to macrophages, lymphocytes, and HLA DR antigens. All the tumours contained macrophages but these cells were more numerous in the atypical meningiomas. Lymphocytes, almost exclusively of the CD8 subtype, were also present in 70% of benign meningiomas and in all atypical meningiomas and were more abundant in the latter.

Pituitary metastasis from malignant bronchial carcinoid.

Metastases from a carcinoid tumor to the pituitary gland have, to our knowledge, not been described. We present a 49-year-old woman diagnosed as having a primary carcinoid tumor arising in the submucosa of a large bronchus who 8 years later presented with multiple metastases including one to the pituitary gland, which was in partial failure of pituitary function. This case illustrates than when confronted with a pituitary tumor resembling an adenoma but negative for pituitary hormones, the possibility of a metastasis from a carcinoid tumor should be considered.

Ependymoblastoma: a histological, immunohistological and ultrastructural study of five cases.

Five ependymoblastomas were studied by means of routine histological techniques, immunohistology and electron microscopy. The tumours were characterized histologically by medium sized, poorly differentiated cells with round or oval nuclei frequently in mitosis and by ependymoblastic rosettes. Reactions for cytokeratin and neurofilament were negative and tubular material positive for glial fibrillary acidic protein was scanty.

Mononuclear cell infiltrate and HLA-DR expression in low grade astrocytomas. An immunohistological study of 23 cases.

Frozen samples from 23 low grade (grade I and II) astrocytomas were studied by means of a panel of monoclonal antibodies to macrophages, lymphocytes (and their subsets) and HLA-DR antigens. Macrophages were present in low to moderate numbers in 38%-86% of cases, the variance in figures depending on the antibody used. T lymphocytes, the majority of CD8 phenotype, were detected in low numbers in 78% of tumours.

Pituicytoma (pilocytic astrocytoma). Case report.

Tumors of the posterior pituitary are rare and the previous nomenclature has been confusing. A 40-year-old man presented with visual failure and disconnection hyperprolactinemia (830 mU/liter) due to a large invasive pituitary tumor shown to be a pituicytoma (pilocytic astrocytoma). Its astrocytic nature was confirmed by positive immunostaining for glial fibrillary acidic protein and the finding of cytoplasmic filaments on electron microscopy.

Immunohistological study of mononuclear cell infiltrate in malignant gliomas.

Sixty-five malignant gliomas (astrocytomas grade 3 and 4 and glioblastomas) were examined by means of immunoperoxidase staining on frozen tissue using various monoclonal antibodies directed against macrophages, lymphocytes and natural killer cells. Depending on the antibody used, the presence of macrophages in tumours ranged from 85%-100%. Many of the tumours contained substantial numbers of macrophages not only, as expected, in necrotic areas but also in intact tumour tissue.

Some hydrodynamic properties of the posterior canal in the frog labyrinth related to neuronal responses.

Measurements of the posterior-canal radius of curvature (R), the semicircular-duct radius (r) and the cupula radius (rC) were performed in the frog labyrinth. The Steinhausen-van Egmond equation led to an estimate of the canal endolymph flow, cupula deflection and sensory hair bending during constant angular accelerations (0.2-64 degrees/s2) of opposite directions and increasing duration (1.

Afferent activity recorded during rotation from single fibres of the posterior nerve in the isolated frog labyrinth.

EPSPs and spikes were recorded at rest and during rotation from single fibres of the posterior nerve in the isolated frog labyrinth. The spike discharge properties of 57 units were examined at rest and during repetitive acceleratory-velocity steps. Forty of these units were subjected to excitatory steps of 5-12 s duration and 45% displayed an evident discharge adaptation.

[Modulating action of barium and other ions on the sensory activity of frog labyrinth].

The effect of Ba2+, TEA, 4-AP and CoCl2 on the EPSP and spike discharges recorded from single fibres of the posterior nerve in the isolated frog labyrinth has been investigated. In Ca-free solution Ba2+ preserved, at low concentration (0.3 mM), the resting activity and at higher levels (up to 6 mM) it resulted in a pronounced facilitation of the EPSP and spike discharges.

[Physical dimensions influence the functional property of the semicircular canal].

The functional dependence of the semicircular canal upon its physical dimensions was evaluated by measuring the internal radius (r), the radius of curvature (R) and the cupula radius (rC) of the posterior canal in 10 freshly dissected frog labyrinths. These values have been compared to the same parameters of the cat labyrinth. The coefficients I, B, K in the Steinhausen equation were determined for both animals.

[Chronic brucellosis: diagnostic problems and case presentations].

Chronic Brucellosis is an infection disease, which is still of great clinical interest whether due to the difficulties of diagnosis involved or to the peculiar course of the illness. For this reasons, we have considered several cases of Chronic Brucellosis observed over a period of 10 years, which have presented particular problems of diagnosis. Furthermore, we have underlined the importance in the diagnosis, of intradermal reaction and the hemoreaction to the anamelitina injection.

[Effects of veratridine on labyrinth receptors in the frog].

The action of the veratrum alkaloid veratridine has been tested on the sensory apparatus of the frog semicircular canals. Intracellular and extracellular recordings of the electrical responses evoked by sinusoidal mechanical stimulations of the ampullar organ could not reveal an action of the drug on the hair cells whereas the onset of the impulse discharge at the encoder of the afferent nerve fibres is largely facilitated by veratridine. The mechanism of the drug action is discussed.

Effectiveness of some anions in sustaining the efferent inhibition in the frog labyrinth.

Efferent inhibition in the frog labyrinth is sustained by the release of acetylcholine (ACh) which opens a Cl(-)-channel in the hair cell membrane. To investigate more closely the nature of the permeability change underlying the ACh reaction, the external Cl(-) was replaced by anions of increasing hydrated size, and to test the possible role of a Cl(-)-pump in the sensory cells, drugs were applied which are known to block active cl(-) pumping in other systems. Experiments indicate that the ACh-operated inhibitory channel of the hair cell is larger than at other inhibitory synapses (or approximately 0.

Reduction of venous sequelae of i.v. diazepam with a fat emulsion as solvent.

Venous sequelae were studied in 93 female patients undergoing minor gynaecological procedures. They were premedicated with diazepam i. v.