[The fly, the fish, and the respiratory physician].
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
M Catala
Publications and source records attributed to M Catala.
Human and monkey fetal brain development of the supramammillary-hippocampal projections: a system involved in the regulation of theta activity.
The supramammillary (SUM)-hippocampal pathway plays a central role in the regulation of theta rhythm frequency. We followed its prenatal development in eight Cynomolgus monkeys (Macaca fascicularis) from embryonic day E88 to postnatal day 12 (term 165 days) and in eight human fetuses from 17.5 to 40 gestational weeks, relying on neurochemical criteria established in the adult (Nitsch and Leranth [1993] Neuroscience 55:797-812). We found that 1) SUM afferents reached the dentate juxtagranular and CA2 pyramidal cell layers at midgestation in human fetuses, earlier than in monkeys (two-thirds of gestation [E109]). They co-expressed calretinin, substance P, and acetylcholinesterase but not gamma-aminobutyric acid (GABA) or glutamic acid decarboxylase (GAD); 2) the presumed parent neurons in the monkey SUM expressed calretinin or both calretinin and substance P; 3) most of them were surrounded by GAD-containing terminals that might correspond to the septo-SUM feedback pathway (Leranth et al. [1999] Neuroscience 88:701); and 4) in addition, a large band of calretinin-labeled terminals that did not co-express substance P, GAD, or acetylcholinesterase was present in the deepest one-third of the dentate molecular layer in both the Cynomolgus monkey and human fetuses. It persisted in the adult monkey but not in adult human hippocampus; it remains questionable whether it originates in the SUM. In conclusion, the early ingrowth of the excitatory SUM-hippocampal system in human and non-human primates may contribute to the prenatal activity-dependent development of the hippocampal formation. The possibility and the functional importance of an in utero generation of hippocampal theta-like activity should also be considered.
Afferent Pathways↗
A case of antenatal cerebral haemorrhage resulting from maternal alloimmunisation against fetal platelets.
Prenatal thrombocytopenia is a rare event and is generally due to fetal infection. In very rare cases, fetal thrombocytopenia is induced by maternal IgG directed against the fetal platelets. This alloimmunisation could lead to in utero bleeding. We now report such a case, in which fetal thrombocytopenia was complicated by a huge temporal lobe haematoma. Such a prenatal event is rare: only eight cases have been published, with only one pathologically confirmed case. Our patient is the second one in which neuropathological examination demonstrated prenatal intracerebral bleeding.
Adult↗
Primary triple teeth: histological and CT morphological study of two case reports.
The macromorphology and micromorphology of two specimens of primary triple teeth using histological and CT analysis approach is analyzed. A single morphological pattern of triple teeth has been found and described: three nearly separate crowns with three separate pulp chambers, and three joined roots with three connected root canals. The characteristic triple teeth appearance occurred because a labial supernumerary tooth is the junction element between two teeth of normal series: the central incisor on the mesial side and the lateral incisor on the distal side. Primary triple teeth suggest an idiopathic abnormality in the distribution of the dental material originated very soon in the dental development. They can be considered as an early double fusion between three tooth germs, initially separate but in close proximity and developing synchronically.
Child, Preschool↗
Monozygotic twins with Crouzon syndrome: concordance for craniosynostosis and discordance for thumb duplication.
Explore the source record for details and available documents.
Craniofacial Dysostosis↗
Alexia for Braille following bilateral occipital stroke in an early blind woman.
Recent functional imaging and neurophysiologic studies indicate that the occipital cortex may play a role in Braille reading in congenitally and early blind subjects. We report on a woman blind from birth who sustained bilateral occipital damage following an ischemic stroke. Prior to the stroke, the patient was a proficient Braille reader. Following the stroke, she was no longer able to read Braille yet her somatosensory perception appeared otherwise to be unchanged. This case supports the emerging evidence for the recruitment of striate and prestriate cortex for Braille reading in early blind subjects.
Blindness↗
The developmental potentials of the caudalmost part of the neural crest are restricted to melanocytes and glia.
The avian spinal cord is characterized by an absence of motor nerves and sensory nerves and ganglia at its caudalmost part. Since peripheral sensory neurons derive from neural crest cells, three basic mechanisms could account for this feature: (i) the caudalmost neural tube does not generate any neural crest cells; (ii) neural crest cells originating from the caudal part of the neural tube cannot give rise to dorsal root ganglia or (iii) the caudal environment is not permissive for the formation of dorsal root ganglia. To solve this problem, we have first studied the pattern of expression of ventral (HNF3beta) and dorsal (slug) marker genes in the caudal region of the neural tube; in a second approach, we have recorded the emergence of neural crest cells using the HNK1 monoclonal antibody; and finally, we have analyzed the developmental potentials of neural crest cells arising from the caudalmost part of the neural tube in avian embryo in in vitro culture and by means of heterotopic transplantations in vivo. We show here that neural crest cells arising from the neural tube located at the level of somites 47-53 can differentiate both in vitro and in vivo into melanocytes and Schwann cells but not into neurons. Furthermore, the neural tube located caudally to the last pair of somites (i.e. the 53rd pair) does not give rise to neural crest cells in any of the situations tested. The specific anatomical aspect of the avian spinal cord can thus be accounted for by limited developmental potentials of neural crest cells arising from the most caudal part of the neural tube.
Animals↗
Astroblastomas revisited. Report of two cases with immunocytochemical and electron microscopic study. Histogenetic considerations.
Explore the source record for details and available documents.
Adult↗
[Intracranial and intraspinal epithelial cysts: a simplified classification].
Explore the source record for details and available documents.
Arachnoid Cysts↗
[Control of the positioning of the vertebrate limb axes during development].
Limbs are formed after a series of complex interactions between tissues derived from the embryonic layers (surface ectoderm and somatopleural mesoderm). Data at both cellular and molecular levels are numerous. The developing limb becomes thus one of the best known system in the field of developmental biology. The limb bud derives from numerous embryonic tissues (surface ectoderm, somatopleural mesoderm, neural crest cells, somites, hematopoietic cells deriving from the splanchnopleura that gives rise to the aortic buds). Multiple interactions take place between these tissues. So, the definitive shape of a structure could depend on only one of its component. For example, the muscular shape is not dependent on the origin of muscle fibers but on the origin of somatopleural cells. Superior (or anterior) and inferior (or posterior) limbs differ by their shape. Some genes expressed by only one of the limb are known but genes specifying the identity of the limbs are still totally unknown. Three axes develop during the formation of the limb buds: proximo-distal, antero-posterior and ventro-dorsal. The formation of the proximo-distal axis is due to the induction of the apical ectodermal ridge, a specialized region of the surface ectoderm in which cells are prismatic and associated by gap junctions. The family of secreted FGF and their receptors play a major role in the regulation of the development of this axis. Furthermore, some genes from Hox complexes a and d participate into the regulation of the positional identity along this axis. The antero-posterior axis is determined by the zone of polarizing activity that secretes Sonic hedgehog. This molecules fashions a gradient of concentration that differentiates the future antero-posterior derivatives. At last, the ventro-dorsal axis depends on the surface ectoderm that have received first positional informations from the mesoderm. The dorsal region is specified by Wnt7a and Lmx1 whereas Engrailed 1 gene plays a role in ventral specification.
Animals↗
From conception to the child.
An attempt to present all the data that account for the progressive transformation of a fertilized zygote into a child at birth is obviously a herculean work. In this review, I focus on four aspects of central nervous system development in which our understanding has considerably been enhanced during the last century. The first part concerns the phenomenon of neural induction, a process devoted to the acquisition of neural identity. It was classically considered that active molecules were secreted by the organizer (the dorsal lip of the blastopore in amphibians and the node in amniotes) and that these molecules induced the neural induction. Nowadays, the model is much more complex, based upon both positive and negative regulatory mechanisms. The positive inductor is BMP4, and this induces the epidermal induction. The organizer secretes negative signals that can bind BMP4 and prevent its action. The second part is devoted to the morphogenetic movements that allow formation of the neural tube. Classically, primary and secondary neurulations are opposed. It is now well established that the two modes of neurulation obey the same basic rules. The problem of segmentation of the central nervous system during embryogenesis could be easily studied for the rhombencephalon. This structure is formed by repetitive subunits called rhombomeres. Each rhombomere corresponds to a compartment separated from the others. In addition, each rhombomere expresses specific genes, and the invalidation of some of them leads to the absence of these rhombomeres. However, the situation is much more complex with regions specified very early during development and acting on adjacent regions to induce a specific pattern. The last part of my paper concerns the development of the cortex. During the last 50 years, all the classic concepts have been challenged. The fixed law of radial migration has been extensively discussed, and it is now admitted that other kinds of migration do take place during corticogenesis. These results force us to reconsider the interpretations of some cortical malformations. It seems reasonable to adopt descriptive terms for a malformative syndrome instead of terms based on putative mechanisms.
Abnormalities, Multiple↗
Craniosynostosis: from a clinical description to an understanding of bone formation of the skull.
The genetic studies of syndromic craniosynostoses lead to the characterisation of genes that regulate the correct development of the bones of the skull. From these studies, it appears that FGF/FGFR signalling has a crucial role in this problem. Numerous mutations affecting the genes coding for FGFR1, 2 or 3 are responsible for these syndromes. It is interesting to note that some identical mutations produced various different phenotypes, suggesting that other genes modulate the phenotypic expressivity. The other involved genes in these syndromes code for such proteins as Msx2 or Twist that interact in the cellular pathways responsible for FGF action. From these genetic studies, it is now important to establish the role of these proteins during the development of the skull. Msx2 plays a repressive role in osteogenesis, whereas FGFRs act as promoting proteins. In the near future, it will be very important to improve our understanding of these phenomena in order to test specific treatments to prevent the development of such syndromes.
Animals↗
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↗
Spinal melanotic schwannoma: a tumour with poor prognosis.
AIM: To clarify the prognosis of melanotic schwannoma. This is a rare tumour which is generally considered as a benign lesion, reported in many cases with a short follow-up only. METHODS AND RESULTS: Five cases of spinal melanotic schwannoma were retrospectively studied. The tumours were examined using standard histological, immunohistochemical and ultrastructural methods. No features of malignancy (high mitotic count, atypia or necrosis) were found in the primary tumours. The follow-up period ranged from 3 to 7 years. Malignant clinical behaviour was clear-cut in four cases: three patients died from metastases to various sites and one presented several discrete spinal tumours of the same type seven years after the first operation. Only one patient presented no recurrence and was free of disease 6 years after initial diagnosis. The review of 57 cases of the literature (including our cases), showed that 15% of the cases had recurrences and 26.3% were complicated by metastasis. Only 53% of the cases followed for more than 5 years, were free of disease vs. 67.5% of the cases with shorter follow-up. Twenty additional cases had no follow-up. CONCLUSION: Appropriate long-term follow-up is required for all melanotic schwannomas, as it may recur or metastasize after more than 5 years, even in the absence of overt malignant histological features.
Adult↗
Primary double teeth. A retrospective clinical study of their morphological characteristics and associated anomalies.
AIM: To investigate the relationship between morphology and position of double teeth, and the occurrence of other dental anomalies in the same subjects and in their siblings. SAMPLE OF CHILDREN AND METHODS: Fifty-three double teeth in a group of 50 Spanish children were included in the study. All of these children were examined clinically and had radiographs and photographs taken at the time of examination. Twenty-two of the children had a total of 30 siblings who were also examined for the presence of anomalies. RESULTS: Of the 50 subjects, 47 had one and three subjects had two double teeth. Statistically there were no significant differences in occurrence between boys and girls, left and right sides or between maxilla and mandible. Four morphological types were identified: type I, bifid crown-single root; type II, large crown-large root; type III, two fused crowns-single root; type IV, two fused crowns-two fused roots. Type I was seen only in the maxilla and types II and III only in the mandible. Type IV was seen mostly in the maxilla. More than half of the cases showed associated anomalies in the permanent dentition and anomalies of number or shape were also present in six of the siblings. CONCLUSION: It is suggested that both double teeth and other anomalies in the same children or in their siblings may be manifestations of a primary abnormality in the distribution of dental material.
Child↗
[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↗
[How sex dimorphism is established in the spinal nucleus of Onuf?].
Some perineal muscles are only present in males. They are innervated by motoneurons located in the ventral horn of the sacral spinal cord in the so-called Onuf's nucleus. This nucleus displays anatomical differences between male and female, constituting a sexual dimorphism. It has been experimentally demonstrated that androgens play a crucial role in the development of this dimorphism. Both proliferation and differentiation of motoneurons in this region are similar in male and female. However, in absence of androgens, motoneurons vanish by programmed cell death, the spinal nucleus after this phase contains a low number of neurons. On the contrary, in presence of androgens, motoneurons survive and the spinal nucleus contains a great number of cells. This hormonal effect is not vehiculated via direct action of androgens on motoneurons but by favoring the survival of striated muscle fibers of perineal muscles. These fibers secrete a trophic factor which acts on motoneurons. CNTF (Ciliary Neurotrophic Factor) is thought to play, at least partially, such a role. At last, after this stage of survival, androgens are involved in dendritic growth of these motoneurons. This effect is mediated by the transformation of androgens into estrogens by neuronal aromatase.
Cell Differentiation↗
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↗