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Biomedical subjects

M Catala

Publications and source records attributed to M Catala.

At least 19 recordsLinked to original sources
PubMed1999

Embryonic expression of the human GATA-3 gene.

The spatial and temporal analysis of GATA-3 expression pattern in the human embryo revealed its expression in new anatomical sites. These include the endoderm of the primitive foregut, pharynx and allantois, the branchial arches and the mesenchymal cells surrounding the stomach and dorsal aorta. On the other hand, human (h) GATA-3 expression in the central nervous system, somites and embryonic kidney confirms the tissue specificity of this gene throughout vertebrate evolution.

DNA-Binding Proteins↗
PubMed1999

[Neuroembryologic considerations on the so-called malformative syringomyelia].

Modern neuroradiological techniques can evidence the presence of liquid-filled spaces within the spinal cord, called syringomyelia. These lesions may be associated with numerous causes, the most frequent of which is an abnormality of the shape of the posterior fossa. Neuropathological analysis of these cavities demonstrates whether they are completely lined by ependymal cells or not. Comparing neuropathological and embryological data suggests that syringomyelia is a secondary deformation affecting a normally-formed spinal cord. The unique case in which such a cavity is really a primary malformation is the so-called myelocytocele. The most frequently encountered lesion associated with syringomyelia is the Chiari abnormality (either type I or II). In this case, the size of the posterior fossa is too small whereas neural elements are normal. Since Chiari abnormality may be familial, some genes are likely to be involved for its generation. In experimental animals, it has been shown that genes belonging to the Hox family or the Mhox gene control the development of the final shape of the occipital bone. Syringomyelia is thus a secondary event affecting the spinal cord and due to a distant cause.

Humans↗
PubMed1998

A novel CNS gene required for neuronal migration and involved in X-linked subcortical laminar heterotopia and lissencephaly syndrome.

X-SCLH/LIS syndrome is a neuronal migration disorder with disruption of the six-layered neocortex. It consists of subcortical laminar heterotopia (SCLH, band heterotopia, or double cortex) in females and lissencephaly (LIS) in males, leading to epilepsy and cognitive impairment. We report the characterization of a novel CNS gene encoding a 40 kDa predicted protein that we named Doublecortin and the identification of mutations in four unrelated X-SCLH/LIS cases. The predicted protein shares significant homology with the N-terminal segment of a protein containing a protein kinase domain at its C-terminal part. This novel gene is highly expressed during brain development, mainly in fetal neurons including precursors. The complete disorganization observed in lissencephaly and heterotopia thus seems to reflect a failure of early events associated with neuron dispersion.

Adolescent↗
PubMed1998

A case of epidermoid cyst arising from the rostral neuropore: case report.

OBJECTIVE AND IMPORTANCE: Supratentorial epidermoid cysts located on the midline are very rare. We describe the first case of such a cyst arising from the rostral neuropore. CLINICAL PRESENTATION AND INTERVENTION: We report a patient suffering from seizures and progressive frontal syndrome and presenting with a huge cyst developed in the midline at the rostralmost part of the corpus callosum. The patient was operated on, and the cyst was found to be epidermoid. CONCLUSION: Only six cases of supracallosal epidermoid cysts have been reported. In our case, the involved region was located at the exact limit between lamina terminalis and corpus callosum. This region corresponds to the place of the closing rostral neuropore during embryogenesis. We thus propose that the cyst arises from the rostral neuropore and that its eventual deep location is explained by the complex morphogenetic movements affecting the dorsal region of the telencephalic vesicle.

Brain Diseases↗
PubMed1998

Embryonic and fetal development of structures associated with the cerebro-spinal fluid in man and other species. Part I: The ventricular system, meninges and choroid plexuses.

Little is known about the development of the central nervous system (CNS) in humans. Ethical considerations preclude experimental studies in this field, and as a result most available data on human ontogenesis are descriptive. Comparative anatomic and embryologic studies have demonstrated that the main developmental milestones are conserved across species, and their results can be used to suggest a likely scenario for human development. The development of the ventricles, meninges, and choroid plexuses are discussed in this article. The central cavity of the neural tube is formed during neurulation, which occurs during the fourth gestational week. The first milestone is occlusion of the spinal neurocele (the central canal in the neural tube) shortly after neurulation. This prevents free communication between the ventricular system and the amniotic cavity. The second milestone is development of the meninges, which separate the central nervous system from the rest of the body. The embryonic origin of the meninges varies across species. In birds (and probably in mammals), the spinal meninges are derived from the somitic mesoderm, the brainstem meninges from the cephalic mesoderm, and the telencephalic meninges from the neural crest. Differentiation of the meninges, which involves formation of the subarachnoid space, occurs early, before the cerebrospinal fluid (CSF) begins to flow around the CNS. During ontogenesis, the meninges play a key role in regulating the growth of underlying nervous structures. They induce the formation of the superficial glial limiting layer and stimulate the growth of precursors located in the superficial blastemas of the cerebellum and hippocampus. The choroid plexuses are complex specialized structures that produce most of the CSF. Their epithelium derives from the neural tube epithelium and their mesenchyma from the meninges. Of the many enzymes produced in the choroid plexuses, some reflect the pivotal metabolic role of these structures (alkaline and acid phosphatases, magnesium-dependent ATPase, glucose-6-phosphatase, thiamine pyrophosphatase, adenylate cyclase, oxidoreductase, esterases, hydrolases, cathepsin D, and glutathion S-transferase). The two enzymes that are crucial to the production of CSF are Na+/K+ ATPase and carbonic anhydrase. Inactivation of catecholamines is mediated by catechol-O-methyltransferase and by the monoamine oxidases A and B. The morphology and synthesis profile of the choroid plexuses changes during development, although little is known about these changes in humans.

Animals↗
PubMed1998

[Pure motor neuropathy after radiation therapy: 6 cases].

We report clinical and neurophysiological characteristics of six patients (five women and one man) presenting a pure motor bilateral asymmetric proximal and distal weakness in the setting of radiation therapy for Hodgkin's lymphoma in four cases, carcinoma of the uterus in one, and cancer of the ovary in one. Motor deficit, amyotrophy, cramps, fasciculations and tendinous areflexia were confined to the lower limbs in five patients and to the upper limbs in one. No sensory or sphincter disturbance was noted. The progression of the disease was slow with sometimes secondary stabilization. In some patients, CSF showed a slight increase in protein content with no cell. Blood and MRI medullary examination were normal. Delay between radiation therapy and onset of neurological symptoms range from 6 to 24 years (mean 15). Neurophysiological findings suggest ventral roots proximal conduction blocks. We found an increase F-waves latency, a complete distal palsy contrasting with persistent muscle action potential after distal stimulation, in most of the patients; and an evidence of a conduction block between the erb point and the cervical roots using magnetic stimulation in the patient with upper limbs involvement. Mechanisms and sites of nerve radiation injury remains still unclear. These data could indicate, as it was already reported, a proximal damage involving predominantly the motor roots.

Adult↗
PubMed1998

[Arachnoid cysts: histologic, embryologic and physiopathologic review].

Arachnoid cysts form a cavity containing a cerebrospinal-like fluid, the wall of which is composed of arachnoidal cells. Other types of intracranial cysts have been described, they differ from arachnoid cysts by the histological characteristics of their wall. To analyze homogeneous series, it is thus necessary to differentiate arachnoid cysts from the other types of cysts. Several localizations of these lesions have been described: the most frequent being the temporo-sylvian area. Arachnoid cysts are considered as resulting from congenital malformations that can change during postnatal life. They can no longer be considered as resulting from cerebral atrophy. This arachnoid malformation could be the primary event or be explained by an impairment of the cerebrospinal fluid drainage generated by venous agenesis. Several mechanisms could account for the inflation of these cysts: secretion by the cells forming the cyst walls, unidirectional valve, liquid movements secondary to pulsations of the veins.

Arachnoid↗
PubMed1998

Neurulation in amniote vertebrates: a novel view deduced from the use of quail-chick chimeras.

Two apparently different mechanisms successively contribute to the formation of the neural tube in the avian embryo: bending of the neural plate during the primary neurulation in the cephalo-cervico-thoracic region and cavitation of the medullary cord during the secondary neurulation in the lumbo-sacral region. During both these processes, gastrulation continues by the caudal regression of Hensen's node--also called cordoneural hinge in the secondary neurulation. Labeling of Hensen's node or cordoneural hinge by the quail chick marker system revealed that this structure, which is the equivalent of the dorsal blastoporal lip of the Amphibian embryo, i.e., of the Spemann's organizer, gives rise to the midline cells of the three germ layers: the floor plate of the neural tube, the notocord and the dorsal cells of the intestinal endoderm. Caudally to the organizer, both in primary and secondary neurulation, the presumptive territory of the alar plates of the future neural tube overlies the precursors of the paraxial mesoderm. Regression of Hensen's node bisects the ectoderm in two bilateral neural plates leaving in its wake the floor plate, the notocord and the dorsal endoderm.

Animals↗
PubMed1997

Embryogenesis. Why do we need a new explanation for the emergence of spina bifida with lipoma?

Spina bifida with lipoma is a human malformation that most often affects the lumbosacral area. It is a complex morphological type. Its origin is controversial, and none of the previous hypotheses can be retained in view of the most recent advances in experimental embryogenesis. Contrary to earlier opinions, adipocytes cannot arise from meninges, vessels or glial cells and spina bifida cannot be explained by incarceration of mesodermal tissues during primary neurulation or developmental defect at the level of the tail bud. Spina bifida with lipoma, which actually involves all the derivatives of the so-called dorsal mesoderm, must therefore result from abnormal development of this mesoderm, which is induced by the dorsal neural tube. The location of the primary defect (dorsal mesoderm or neural tube) remains to be established.

Embryonic Induction↗
PubMed1997

Carbonic anhydrase activity during development of the choroid plexus in the human fetus.

Carbonic anhydrase is one of the key enzymes responsible for the secretion of cerebrospinal fluid. This secretion increases dramatically during postnatal life in mammals. Nothing is known that can account for this regulation in the neonatal choroid plexus. However, the expression of carbonic anhydrase is developmentally regulated in several cells, such as erythrocytes and striated muscle fibers. The aim of our study was to assess the presence of carbonic anhydrase in epithelial cells of the choroid plexus during human development. We performed both histochemical and immunohistochemical detections of the enzyme on choroid plexuses between 9 and 34 weeks of gestation. We found that both carbonic anhydrase activity and the isozyme II were present as early as the 9th week of gestation. expression of carbonic anhydrase is thus a very early event during plexus differentiation, and this enzymatic system could account for the secretion of cerebrospinal fluid during fetal life.

Carbonic Anhydrases↗
PubMed1997

Embryonic neural chimeras in the study of vertebrate brain and head development.

Construction of neural chimeras between quail and chick embryos has been employed since 1969 when the unique nucleolar structure of the quail nucleus and its use to devise a cell marking technique by associating quail and chick cells in ovo were described in the "Bulletin Biologique de la France et de la Belgique." This method was first applied to the ontogeny of the neural crest, a structure whose development involves extensive cell migration, and, since 1984, to that of the central nervous system (CNS). This chapter highlights some of the most significant findings provided by this approach concerning the CNS, such as (i) demonstration of the common origin of the floor plate and notochord from a group of cells localized in the "organizer", i.e., Hensen's node, and the way in which these two structures become positioned respectively within and under the neural tube during gastrulation and neurulation in Amniotes; (ii) the neural crest origin of the skull vault and the facial and hypobranchial skeleton. This means that the mesodermal contribution to the skull is limited to the occipital and otic regions and extends only to the rostral limit of the notochord. A correlation can be drawn between the development of the telencephalon and the mesectodermally derived skull in the vertebrate phylum; (iii) demonstration that the midbrain-hindbrain junction, at the stage of the encephalic vesicles, acts as an organizing center for tectal and cerebellar structures. This function was correlated with the activity of several developmental genes, thus providing insight into their function during neurogenesis; (iv) the pattern of morphogenetic movements and cell migration taking place in defined brain-to-be areas, as well as the origin of various cell types of nervous tissues; and (v) a new avenue for studying brain localization of either behavioral traits or genetically encoded brain disorders.

Animals↗
PubMed1997

Dorsal mesencephalic lipoma with inferior collicular hypoplasia: a case report and review of literature.

Intracranial lipomas are rare lesions the pathogenesis of which is still a matter of debate. We report the case of a patient presenting an asymptomatic lipoma located in the quadrigeminal and supra-cerebellar cisterns. The lipoma was associated with hypoplasia of the right inferior colliculus and of the rostral part of the vermis. Analysis of the relationships between neural tube and meninges prompts us to propose that the primary event of this malformation is a defect of the neural anlage which gives rise to both nervous dysplasia and lack of meningeal induction responsible for lipoma development.

Adult↗
PubMed1997

Epilepsy with myoclonus and post-natal development of the motor system in humans: a hypothesis.

Epilepsy with myoclonus is thought to be linked to the motor system. At birth, development of the central nervous system in humans is far from being achieved. Post-natal changes take place at different levels in this neuronal system. These modifications suggest that the motor cortex is a highly dynamic structure during post-natal development. They may account for the age-dependence of various epileptic syndromes. (1) The number of synapses increases during the early post-natal years and then decreases to reach the adult level around puberty. (2) Neurons differentiate and synthesize various neurotransmitters. (3) Dendrites grow actively and participate in the formation of local cortical circuits. (4) Electrophysiological properties of cortical neurons change during the first months of rodent development. This could reflect modifications of the ion channels present in the cell membrane. (5) The pyramidal tract myelinate and exuberant collaterals are selectively removed. These two processes are dependent on neuronal electrical activity. It has been demonstrated that selective collateral stabilization is promoted by glutamate release and stimulation of the N-methyl-D-aspartate (NMDA) receptor. So, seizures occurring during the neonatal period may interact with these normal developmental features. Furthermore, neuronal electrical activity and seizures stimulate the transcription of specific messenger RNAs coding for neurotrophic factors like nerve growth factor (NGF) or brain-derived neurotrophic factor (BDNF). The overproduction of neurotrophic factors leads to maldevelopment of the cortex.

Animals↗
PubMed1997

Progressive facial hemiatrophy and epilepsy: a common underlying dysgenetic mechanism.

Progressive facial hemiatrophy (PFH), a rare disorder characterized by progressive and self-limited atrophy of the skin and the subcutaneous tissues, is often associated with epilepsy but the link between these two conditions is poorly understood. The cause of PFH remains unclear. We report four patients with PFH associated with partial epilepsy in whom brain MRI showed cerebral dysgenesis. The four patients (two men, two women; age range: 24 to 73 years) developed parasagittal PFH in their second decade. Seizures started before the age of 20 years in three patients and were refractory simple, or complex partial seizures. All the patients had focal MRI showing cortical dysgenesis, ipsilateral to PFH, consisting of cortex thickening, gyral effacement, and blurring of the white-gray interface. The underlying white matter was hyperintense on T2-weighted sequences, with nodular areas in two patients. These areas were stable over time, without contrast enhancement, and were consistent with the MRI characteristics of cystic encephalomalacia. These neuroradiologic features suggest a localized cerebral hemispheric defect of congenital origin. Because cells participating in the formation of the fronto-nasal bud derive from common progenitors with the cells that give rise to the cerebral hemisphere, we suggest that an early malformative process affecting one side of the rostral neural tube could underlie both cerebral dysgenesis and facial hemiatrophy.

Adult↗