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J P Misson

Publications and source records attributed to J P Misson.

At least 19 recordsLinked to original sources
PubMed2006

[Epilepsy in children with cerebral palsy].

The incidence of epilepsy in 110 patients with cerebral palsy (the majority with spastic tetraplegia) was 46,4%. Almost half of the patients with spastic tetraplegia (45%) and hemiplegia (52%) had epilepsy. The incidence was lower in patients with spastic diplegia (32%). Half of epilepsy in spastic hemiplegia were partial seizures and the other half consisted of generalized seizures, while generalized tonic-clonic episodes predominated in all other forms of C.P. A high incidence of West syndrome was observed in patients with spastic tetraplegia. Etiological factors of C.P. were perinatal in 75%. 16,65% had neonatal antecedents of convulsions; most of them had spastic tetraplegia (75%) and a significant mental retardation. A low intelligence quotient (I.Q.) was seen in most of the children with epilepsy, and patients with tetraplegia had significantly lower intelligence quotient than other groups.

Adolescent↗
PubMed2004

[Epileptic and non-epileptic paroxysmal phenomenons in the child].

In neuropediatry, paroxysmal phenomenons characteristic of the child can be of an epileptic or non epileptic origin. A correct clinical diagnosis has to be done straightaway in order to best select the complementary exams, establish the prognosis and decide the treatment. We will describe the clinical presentation of the main paroxysmal phenomenons found in children.

Child↗
PubMed2004

Bony syngnathia, vertebral segmentation defect, coloboma, microcephaly and mental retardation: confirmation of Dobrow syndrome and review of syndromal syngnathias.

Congenital bony fusion of the maxilla and mandible is a rare condition. Two classifications were previously proposed dealing exclusively with craniofacial malformations. Most of the reported cases to date represent either aglossia-adactylia or hemifacial microsomia syndromes. We report a young girl with bony syngnathia associated with multiple defects (severe microcephaly, coloboma, vertebral segmentation defects), growth and mental delay. This patient is very similar to the patient described by Dobrow in 1983 and confirms the existence of this extremely rare disorder.

Coloboma↗
PubMed2003

[Catecholaminergic polymorphic ventricular tachycardia in a child: an often unrecognized diagnosis].

UNLABELLED: Catecholaminergic polymorphic ventricular tachycardia is important to be diagnosed as an underlying disease in children with syncope and normal heart, because of its poor prognosis. CASE REPORT: A 3-year-old boy was referred for stress and emotion induced syncope. Primary ventricular arrhythmia, consisting of salvos of bidirectional ventricular tachycardia, was reproducibly induced by physical exertion. The syncopal events and severe arrhythmia disappeared with beta-blocking therapy. CONCLUSION: Despite its rare occurrence, catecholaminergic polymorphic ventricular tachycardia is an important cause of stress and emotion induced syncope and sudden death in children.

Adrenergic beta-Antagonists↗
PubMed2001

[How I investigate...difficult cases of tuberculous meningitis].

To formally document the presence of the bacillus of Koch in meninges still remains difficult and depends on many variables. We report two cases where the diagnosis proved difficult. The presentation of tuberculous meningitis can take several aspects. Mantoux reaction is frequently negative. The BK cultures, which demonstrate the diagnosis, depend on the volume of CSF and on the importance of BK dissemination. It, unfortunately, remains difficult to make the diagnosis of tuberculous meningitis even though this pathology can have extremely deleterious consequences.

Adolescent↗
PubMed1999

Infantile and juvenile presentations of Alexander's disease: a report of two cases.

We describe 2 new cases of Alexander's disease, the first to be reported in Belgium. The first patient, a 4-year-old girl, presented with progressive megalencephaly, mental retardation, spastic tetraparesis, ataxia and epilepsy: post-mortem examination showed widespread myelin loss with Rosenthal fibers (RFs) accumulation throughout the neuraxis. She was the third of heterozygotic twins, the 2 others having developed normally and being alive at age 5 years. The second patient developed at age 10 years and over a decade spastic paraparesis, palatal myoclonus, nystagmus, thoracic hyperkyphosis and thoraco-lumbar scoliosis with radiological findings of bilateral anterior leukoencephalopathy. Brain stereotactic biopsy at age 16 years demonstrated numerous RFs. With these 2 cases, we review the literature on the various clinico-pathological conditions reported as Alexander's disease. We discuss the nosology of this entity and the pathogeny of RFs formation and dysmyelination. Clues to the diagnosis of this encephalopathy in the living patient are briefly described.

Adolescent↗
PubMed1998

Prenatal diagnosis of pyruvate carboxylase deficiency by direct measurement of catalytic activity on chorionic villi samples.

Pyruvate carboxylase (PC) deficiency is a rare metabolic disorder in infants and children, most frequently with fatal outcome. Its prenatal diagnosis by radiometric assay in cultured amniocytes has previously been reported. We present and discuss the prenatal diagnosis of PC deficiency by direct measurement of PC activity in chorionic villi, in two subsequent pregnancies in a family who previously lost a child affected by PC deficiency. In the next pregnancy PC was unmeasurably low in chorionic villi whereas in control samples its activity was between 0.8 and 3.3 nmol min-1 mg protein-1. Following elective termination of the pregnancy PC was shown to be totally inactive in post-mortem fetal liver. In the most recent pregnancy of the proband's mother PC was normally active in the chorionic villi. The product of this pregnancy was a normal boy.

Chorionic Villi↗
PubMed1997

Microcephaly, muscular build, rhizomelia, and cataracts: description of a possible recessive syndrome and some comments on the use of electronic databases in syndromology.

We report on a 7-year-old boy born of consanguineous parents with severe microcephaly (-5 SD) but borderline intelligence, juvenile cataract, muscular build, rhizomelic shortness of limbs predominantly of femora, advanced bone age, and micropenis. This combination of signs appears unique and may represent an undescribed, possibly autosomal recessive MCA syndrome. The use of LDDB and POSSUM in the workup of such "new syndromes" is reviewed. Three search strategies are discussed: single rare sign browsing, best combinatory fit using an array of key words, and combined rare signs scan. Pitfalls in the use of such databases and the some problems raised by inconsistent/ incomplete encoding in those two popular, highly useful syndromology retrieval systems are discussed.

Cataract↗
PubMed1995

Heterogeneity of SPONASTRIME dysplasia: delineation of a variant form with severe mental retardation.

We report a child with short stature, osteopenia with metaphyseal striations and severe mental retardation. This child shows radiological and clinical features of SPONASTRIME dysplasia. Only three sibships with this disorder have been reported. In two families, affected patients were of normal intelligence. In the third one, as well as our case, the dysplasia was complicated by severe mental retardation of unknown origin. The severity of the retardation in our case and a previous report, and some difference in the gestalt and radiological aspects, suggest that SPONASTRIME dysplasia is a heterogeneous disorder. We provisionally propose to split SPONASTRIME dysplasia in two phenotypically distinct subgroups, and to delineate here a 'new' variant with microcephaly and severe mental impairment.

Bone Diseases, Developmental↗
PubMed1993

Heterogeneity versus variability in megalocornea-mental retardation (MMR) syndromes: report of new cases and delineation of 4 probable types.

Megalocornea (corneal diameter > or = 13 mm) is associated with mental and neurological impairment, and minor anomalies in Neuhäuser syndrome (megalocornea-mental retardation syndrome). Here we report 4 new cases of megalocornea and mental retardation. Those unrelated patients have a consistent pattern of anomalies with possible recessive inheritance which clearly differs from that of the original patients of Neuhäuser et al. [1975]. We discuss the heterogeneity of the syndromes with megalocornea and mental retardation. Based on these cases and on a review of the literature, we suggest a provisional clinically oriented classification in 5 subtypes: (1) a recessive form type Neuhäuser (with iris hypoplasia and minor anomalies), (2) a recessive form type Frank-Temtamy (with camptodactyly, scoliosis and growth retardation), (3) a recessive type 3, including our 4 personal cases (with normal irides, severe hypotonia, relative or absolute macrocephaly and minor anomalies), (4) a possible Frydman type (with normal irides, megalencephaly and obesity), and (5) provisionally unclassifiable cases.

Abnormalities, Multiple↗
PubMed1992

Early neurogenesis and teratogenesis in whole mouse embryo cultures. Histochemical, immunocytological and ultrastructural study of the premigratory neuronal-glial units in normal mouse embryo and in mouse embryos influenced by cocaine and retinoic acid.

Yolk sacs of postimplantation mouse embryos were cultured in a mixture of human and rat sera. The central nervous system of these cultured normal embryos was studied from the stage of 5-9 somites (approximately 8.5 postcoital days) to 20-21 somites (approximately 9.5 postcoital days) and compared with in vivo embryos at the same stages. This developmental period covers most of the neural tube closure, the early premigratory differentiation of the neuroectodermal epithelium, and the glial commitment of a population of germinative cells. The neuronal and glial elements of the in vitro cultivated embryos were found to be identical to the corresponding neural tissue in in vivo embryos (light and electron microscopic comparisons); the morphological identity between the in vivo and in vitro embryos was confirmed by morphometry and by stainings revealing the differentiation of the glial elements and precursors. The study of the neuronal-glial units in this material revealed that the fascicular organization of the radial glial cells occurs before the stage of 20 somites. When submitted to a single low dose of retinoic acid at the 7-somite stage, the expression of the epitope recognized by radial cell 2 (RC2), a glial marker, is delayed in the in vitro embryos 12-16 hours, but the glycogen and the other glial parameters mature in time. The in vitro embryos exposed to cocaine at the 7-somite stage displayed a prosencephalon remaining deprived of almost all glial cytological features during the entire culture period, although the other developmental parameters evolved normally. This in vitro whole embryo model seems to be a powerful tool for studying early neurogenesis and teratogenesis.

Animals↗
PubMed1990

Glial process elongation and branching in the developing murine neocortex: a qualitative and quantitative immunohistochemical analysis.

Cells of astroglial lineage in the murine cerebrum undergo a succession of transformations during prenatal and early postnatal development. The bipolar radial cell, the earliest astroglial form to appear, provides a radially aligned, parallel array of fibers that serves as a guide to neuronal migration. The multipolar astrocyte is the representative of this lineage that persists in the adult cerebrum. The processes of the multipolar astrocytes form a complex reticulum, which is considered critical to the development, function, and maintenance of neural circuits. A monopolar radial cell appears to be transitional between the two. The shift from the radial glial fiber system to a diffuse glial network is achieved largely in the E17-P2 interval in the mouse. This phenomenon has been studied qualitatively and quantitatively by staining cerebral tissue with monoclonal antibody RC2, a specific and sensitive ligand for cells of astroglial lineage in the mouse. Elongation and branching of glial processes contribute to the glial transformation. Elongation of radial fibers occurs under the guidance of other radial glial fibers (fasciculated elongation) or independently of other fibers (nonfasciculated elongation). Fasciculated elongation results in an increase in the density of radial glial fibers that span the cortical layers. Nonfasciculated elongation appears to be associated with process branching. This is the initial event in transformation of the bipolar radial cells to monopolar radial or multipolar cells. Only nonfasciculated elongation is characteristic of processes of the monopolar radial cells and multipolar astrocytes. Branching of the processes of all three cell forms appears to occur both by bifurcation at the elongating tip and by sprouting from the fiber shaft. Elongating fibers are tipped by growth cones that are relatively simple in shape as compared to those observed at the tips of elongating axons. Growth cones at the tips of nonfasciculated fibers are more complex in form than those at the tips of radial fibers elongating in contact with other radial fibers.

Animals↗
PubMed1990

The development of radial glia and radial dendrites during barrel formation in mouse somatosensory cortex.

The development of the mouse barrel field (the mystacial whisker representation in SI cortex) was examined using immunocytochemical probes for radial glia and neuronal dendrites. The maturing dendrites were revealed using antibodies against microtubule-associated protein 2 (MAP2) and the radial glia were demonstrated with a recently described monoclonal antibody, RC2. By postnatal day 7 both antibodies clearly demonstrated a non-uniform distribution of dendrites and glia that was unique to layer IV of the barrel field. Both MAP2-immunoreactive dendrites and RC2-immunoreactive radial glial fibers were dense near the walls (sides and septae) of barrels than near the hollows (centers) of barrels. In contrast, in other cortical regions, radial glia and dendrites did not appear obviously patterned. Not until postnatal day 4 did the pattern of both radial glial fibers and apical dendrites begin to emerge in a barrel-like distribution. We conclude that the non-uniform distribution of radially oriented dendrites and radial glial fibers appears with a similar developmental time course to that described for the appearance of the cellular barrels themselves.

Aging↗
PubMed1990

A disorder of axonal development, necrotizing myopathy, cardiomyopathy, and cataracts: a new familial disease.

We report severe congenital encephalopathy and profound hypotonia associated with necrotizing myopathy, cardiomyopathy, and cataracts in 3 infants, including 2 sisters. Brain scans suggested agenesis of the corpus callosum. Neuropathological findings consisted of severe atrophy of the corpus callosum (not the usual agenesis with longitudinal callosal bundles), atrophy of the white matter, and absence of pyramidal tracts in the medulla. Multiple axonal swellings were present in the white matter and in Purkinje cells. Except for the corpus subthalamicum, gray matter structures were preserved. These findings are considered to be the expression of a primary disorder of axonal development leading to a reduction in interneuronal synaptic contacts. It is suggested that the anomaly may be due to an extension of the normal phenomenon of axonal elimination, related to a primary defect of the axonal cytoskeleton. The concept of a primary axonal disorder may also apply to other, mostly familial, conditions with progressive atrophy of the cerebral white matter and corpus callosum.

Atrophy↗
PubMed1989

Dynamic structure of the radial glial fiber system of the developing murine cerebral wall. An immunocytochemical analysis.

Dramatic changes occur in the radial glial fiber system of the murine forebrain in the course of neocortical histogenesis. Initially, prior to substratification of cortical and subcortical anlagen between E13 and E14, the system is uniformly radial in alignment. It appears to achieve maximum density and to be highly uniform in structure throughout its radial span, both in terms of apparent fiber density and the pattern of arrangement of fibers in fascicles. Subsequent to E14, concurrently with rapid growth of the cerebral wall and with the differentiation of the cortical substrata and intermediate zone, the subcortical segment of the system becomes laterally arced while the transcortical span of the system remains radially aligned. Although the spacing between fascicles changes little, there is an apparent general drop in fiber density associated with a progressive reduction in the number of fibers per fascicle. The changes in relative positioning of the fibers and the apparent decline in fiber density are most dramatic within the developing cortical plate and subplate and may be of specific significance for the migration and radial assembly of the neurons in the supragranular neocortical layers.

Animals↗
PubMed1988

Identification of radial glial cells within the developing murine central nervous system: studies based upon a new immunohistochemical marker.

The monoclonal antibody RC2 was generated in mouse by conventional hybridoma methodology. The antigen recognized by RC2 is robust, allowing aldehyde fixation appropriate to high resolution light and electron microscopic analyses. From the neural tube stage of fetal development the antibody delineates throughout the central nervous system a subpopulation of neuroepithelial cells which have a radial bipolar morphology. A descending process extends to the ventricular margin, and an ascending process contacts the glial limiting membrane by one or more endfeet varicosities. The persistence of these cells through the neurogenetic period allows their identification as radial glial. From as early as E9-10 the fibers appear to be organized in simple straight fascicles. Later in fetal development these fascicles show marked region-specific transformations in density and trajectory, particularly in association with cerebral corticogenesis and with cerebellar and basal ganglia development. The bipolar forms continue to stain with RC2 until they disappear in the postnatal period. Concurrently with a progressive perinatal loss of stained bipolar radial glia, RC2 identifies multipolar cell forms at various levels of the brain wall, as consistent with the transformation of radial glia into astrocytes. RC2 also recognizes monopolar cell forms in the spinal cord and the cerebellum as early as E15, and in the dentate gyrus of the hippocampal formation from the day of birth. Monopolar forms in the cerebellum are inferred to be progenitors of Bergmann glia. Although Bergmann glia are known to persist in adult life, these cells do not stain with RC2 beyond the 2nd postnatal week. The robustness of the antigen recognized by RC2 makes this probe a valuable tool to study the morphological transformations of the bipolar radial glia during their mitotic turnover. It also provides a sensitive stain for the study of the organization and the histogenetic role of the overall radial fiber system.

Aging↗
PubMed1988

Mitotic cycling of radial glial cells of the fetal murine cerebral wall: a combined autoradiographic and immunohistochemical study.

Radial glial cells of the embryonic murine cerebral wall are selectively labeled by staining with antibody RC1. In order to study the mitotic cycling of these cells, we combined RC1 immunohistochemistry and autoradiographic analysis following [3H]thymidine injection at 1, 2, 6, 48 h prior to sacrifice. Many radial glial cells, i.e. RC1-positive cells, incorporate the DNA tracer and hence must be mitotically active. Other proliferative cells of the ventricular zone do not stain with RC1. With the transition from S to M phase, the nuclei of the radial glial cells participate in the interkinetic 'to-and-fro' nuclear translocation characteristic of the non-radial glial cells of the ventricular zone. The density of radioactive grains over nuclei of both RC1-positive and negative cells of the ventricular zone becomes similarly reduced in the 48 h following the [3H]thymidine incorporation. Thus, the subpopulation of radial glia with nuclei within the ventricular zone which have incorporated the DNA tracer does not appear to become arrested in a prolonged G1 phase. The results suggest that the ventricular zone includes at least two subpopulations of stem cells, neuronal and radial glial. Radial glial cells, i.e. RC1-positive cells, are inferred to serve initially as a progenitor population for new radial glial cells. Later in development, they probably become a source of other cells of astroglial lineage.

Animals↗