Biomedical subjects

A M Goffinet

Publications and source records attributed to A M Goffinet.

80 records · Page 5Linked to original sources

PubMed1981

A Golgi study of the brain malformation in Zellweger's cerebro-hepato-renal disease.

Characteristic neuronal heterotopias in two cases of Zellweger's cerebro-hepato-renal disease were studied with the Golgi method. In the corona radiata, heterotopias consist of large fields of small or medium-sized radial pyramids, and of dense clusters containing larger, randomly oriented pyramidal cells and multipolar neurons, some of which resemble granule cells. The latter type of heterotopia could result from a focal destructive process at a relatively early stage of neuronal migration. In the cerebellar white matter, heterotopic masses contain Purkinje cells and possibly Golgi neurons but no granule or basket cells. The mispositioned Purkinje cells resemble the subcortical and intragranular Purkinje cells of the reeler mutant mouse and those of the weaver mutant. The morphology of neurons in the abnormally convoluted olivary nucleus is normal.

Bile Ducts, Intrahepatic↗

PubMed1980

The cerebral cortex of the reeler mouse embryo. An electron microscopic analysis.

The cerebral cortex of reeler (rl/rl) and control (rl/+) embryos has been examined at embryonic day 14 (EO = day of the plug). At this early stage, the cells of the cortical plate in reeler are characteristically maloriented when compared to the controls but, despite this malorientation, they assume a normal differentiation; in particular the regions of contact between the cells or the cortical plate are not different from the controls. The marginal zone and the subcortical plate of reeler are less well delimited than in normal fetuses, yet each of these layers contains the same contingent of cells and fibers as the normal embryos. In particular an early afferent fiber system is visualized in reeler and shows the same characteristics as in normal embryos: weak osmiophily, presence of dense core vesicles and of multilocular dense vacuoles, formation of asymmetric synapses in the marginal zone. The nature of these fibers is unknown but it is suggested that they could correspond to the aminergic system described in rats at the same developmental stage. The observations reported, though compatible with the hypothesis that the reeler gene acts upon a cell recognition-adhesion phenomenon between CP cells, do not provide a positive evidence for it and do not exclude other explanations.

Animals↗

PubMed1979

An early development defect in the cerebral cortex of the reeler mouse. A morphological study leading to a hypothesis concerning the action of the mutant gene.

Brains of reeler and normal mouse embryos have been studied on semi-thin sections and with Golgi impregnations. No change can be seen in the neuroepithelium or in the primary cortical organization. The first evidence of a morphological abnormality appears at E 14, in the cortical plate. Instead of being closely packed and radially oriented, nerve cells are loosely arranged and show quite variable orientations of their long axis and apical dendrite. The axons run obliquely through the cortical plate and do not display the characteristic angular course seen in the normal animal. It is suggested that the primary defect in reeler mice may be in the plasma membrane of cortical plate cells, resulting in a loss of their capacity for mutual recognition and binding. This could account for the cytoarchitectonic disorganization in this mutant, especially the absence of a molecular layer and the inversion of the histogenetic gradient in the developing cerebral cortex.

Animals↗

PubMed1979

Early histogenesis in the mouse cerebral cortex: a Golgi study.

The early histogenesis in the cerebral cortex of the mouse was studied with a modification of the rapid Golgi method. Three stages can be distinguished first, a period during which the telencephalon is exclusively populated with neuroepithelial cells (till E12); secondly the transient stage of the primordial cortical organization, characterized by the presence, in the outer part of the neural tube, of a loose network of primitive horizontal nerve cells and third, the appearance of the early cortical plate (E14) which contains closely packed, radial bipolar nerve cells. In addition to some salient morphological features of the various cell types, the technique also reveals the importance of efferent fibers from the cortex during the early cortical development.

Animals↗

PubMedDate not supplied

Brain metabolism in mitochondrial encephalomyopathy: a PET study.

Regional brain glucose metabolism has been studied in a case of mitochondrial encephalomyopathy with ragged red fibers, using positron emission tomography with fluorodeoxyglucose as the tracer. A marked decrease in glucose utilization was found in all gray structures, with a preponderance of metabolic alterations in posterior cortical regions and thalamus and a relative sparing of anterior cortical areas and basal nuclei.

Adult↗

PubMedDate not supplied

Autoradiographic analysis of adrenergic receptors in the mammalian brain.

Noradrenaline (NA) exerts its physiological and pharmacological effects in the central nervous system by interacting with specific receptor sites which are divided into four subtypes, namely alpha-1, alpha-2, beta-1 and beta-2 adrenoceptors. Alpha-1 and beta-1 receptors are thought to be neuronal and post-synaptic, whereas alpha-2-R are neuronal pre- and postsynaptic and beta-2-R have a non neuronal (glial, vascular) localization. The autoradiographic localization of adrenergic receptors is requisite to a better understanding of adrenergic modulation in the nervous system. It complements analyses of adrenergic fibers and terminals and allows comparisons between afferent transmission and various receptor systems. In addition, receptor autoradiography is a preliminary step towards non invasive, in vivo receptor imaging using positron emission tomography (PET). Classical autoradiographic methods using tritium-labeled ligands are relatively tedious, as they require exposure times of several months. In order to circumvent these difficulties, an autoradiographic procedure was developed for visualization of I-125-labeled ligands. The method is validated by its application to the analysis of neuronal postsynaptic (alpha-1 and beta-1) adrenoceptors, in ferret visual cortex, in the forebrain of normal and reeler mutant mice and in the embryonic mouse brain. Distributions of alpha-1 and beta-1 adrenoceptors are studied using revelation of HEAT and ICYP binding sites, respectively. The cerebral cortex of ferret was chosen because it is widely used in vision research. The density of both alpha-1 and beta-1 adrenoceptors shows laminar heterogeneities. Beta-receptors are most heavily concentrated in cortical layers I, II and III, but very low in layer IV and moderately represented in layers V and VI. In contrast, alpha-1 receptors are more diffusely distributed, although preferentially concentrated in layer IV and, to a lesser extent, in upper cortical laminae. The two adrenoceptors are thus segregated in the radial dimension of the cortex, following distributions which are nearly complementary. These observations suggest that alpha- and beta-adrenoceptors might be associated with different stages and/or modes of information processing in the primary visual area. Adrenoceptor distribution was mapped in normal and reeler mice, in order to correlate receptor patterns with architectonic anomalies known to exist in reeler mutant mice. In normal mice, beta-1-receptors predominate in striatum, cortical layers I to III, hippocampal regio superior and some thalamic nuclei; they are moderately concentrated in cortical layers V and VI and poorly represented in lamina IV.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenergic Fibers↗

PubMedDate not supplied

[Cerebral glucose metabolism in autistic children. Study and positron emission tomography].

Brain glucose metabolism was measured in 18 autistic children, using high resolution positron emission tomography (PET Scan), with fluorodeoxyglucose (FDG) as tracer. Measurements were performed on an ECAT III tomograph (CTI). Global brain glucose utilization in the autistic population was slightly more elevated than in young adult volunteers, particularly in frontal cortical regions, an observation previously reported for adult autists (Rumsey et al., 1985). However, mean brain glucose metabolism did not differ significantly from that of control children. Regional metabolic maps were also normal, although there was evidence for heterogeneities, particularly at the level of prefrontal and parieto-occipital association areas: 6 children showed a relative hyperfrontality whilst hypofrontality was found in 2 cases. These data suggest that PET might be useful for a better definition of subsets of autistic syndrome in children.

Adolescent↗

PubMedDate not supplied

[Tick-bite meningoradiculitis (author's transl)].

Meningoradiculitis due to tick-bite is rare and poorly documented. Its etiology remains hypothetical, but is thought to be caused by a viral infection carried by the tick. It is characterized by a striking clinical picture, especially symptoms of a subjective nature. The involved area extends asymmetrically from the site of the bite with variable latency. The CSF is characteristic, showing definite lymphocytosis and a moderate protein reaction. The prognosis is excellent although recovery may take several months. In the event of facial paralysis, there is a risk of postparalytic spasms. Treatment is symptomatic; no drug has proved effective.

Aged↗