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At least 37 records · Page 2Linked to original sources
PubMed1981

[Congenital functional disorders of the hypothalamus caused by a development disorder of the prosencephalon].

The case histories of three boys with a micropenis, abnormal facial features and congenital hypopituitarism are described. Two of the boys in addition had congenital deformities of the feet. A prolonged neonatal jaundice or a neonatal hepatitis, and an abnormal mental development was also found. This complicated syndrome is caused by impaired development of the prosencephalon. The ensuing anatomical changes have been called holoprosencephaly. Early recognition of this syndrome rests on the micropenis and the abnormal facial features.

Abnormalities, Multiple↗
PubMed2002

Temporal sequence of gene expression leading caudal prosencephalon to develop a midbrain/hindbrain phenotype.

Transplantation of prosomeres 1-2 into the cerebellar plate were used, by using chick/quail chimeras, to analyse the temporal sequence of the genetic cascade leading the graft to develop a midbrain/hindbrain phenotype. Our results show that (1) at Hamburger and Hamilton (HH) stage 13, Pax2 and En2 are already induced within the graft, before all other genes of the cascade, whereas misexpression of Fgf8 is also observed within the contiguous host cerebellar plate; (2) within the graft, Otx2 repression and Gbx2 induction (see Hidalgo-Sánchez et al. [1999] Development 126:3191-3203) are secondary events that affect, from stages HH14-15, the areas in contact with the host Gbx2/Fgf8-expressing cerebellar plate; (3) at these stages, the repressed Otx2 territory extends beyond the areas induced to express Gbx2, with the two territories not abutting before HH17-18; (4) Fgf8 expression becomes progressively induced within the Otx2-repressed/Gbx2-induced territory, starting at HH15-16. Our results support the hypothesis that the host-Gbx2/graft-Otx2 interface could trigger the genetic cascade induced within the graft and that the Gbx2-induced domain could play a key role during the establishment of the induced intragraft midbrain/hindbrain boundary.

Animals↗
PubMed1999

Distribution patterns of vimentin-immunoreactive structures in the human prosencephalon during the second half of gestation.

Neuronal migration is guided by long radially oriented glial fibres. During late stages of development radial glial cells are transformed into astrocytes. A predominant intermediate filament protein within radial glial cells and immature astrocytes is vimentin. In this study fetal brain sections were used to demonstrate the transient features of vimentin-positive radial glia. In the lower half of the cerebral wall of the 6th gestational month bundles, curvature, and crossing of vimentin-positive fibres are regularly seen. Moreover, fibres terminating on vessels are observed. In the upper half fibres are radially oriented; when ascending towards the pial surface the number and diameter of fibres appears conspicuously decreased. Radially aligned fibres display numerous varicosities. In the 8th month the bulk of vimentin-positive fibres is encountered next to the ganglionic eminence and below isocortical cerebral fissures. The dentate gyrus is conspicuous due to its high amount of immunolabelled fibres. Furthermore, densely packed fibres are visible within the internal and external capsule and in the vicinity of the anterior commissure. Radial glial somata are found in the proliferative areas as well as in the adjacent white matter. In the latter location bipolar, monopolar and stellate vimentin-positive cells are present. The results demonstrate an area-specific distribution pattern of vimentin-positive structures which can be correlated with migrational events. Areas maturing late in development for instance, reveal dense immunolabelling in the 8th month. The orientation and position of radial fibres point to an additional developmental role of these fibres, i.e. their involvement in the guidance of growing axons. Moreover, the arrangement and morphology of vimentin-positive fibres, such as retraction of fibres or occurrence of varicosities, are indicative of degenerative events. Accordingly, a transformation of radial glial somata, their displacement towards the white matter and finally the growth of stellate processes can clearly be demonstrated.

Astrocytes↗
PubMed1985

The cerebellar and vestibular nuclear complexes in the turtle. II. Projections to the prosencephalon.

Prosencephalic projections from the cerebellar and vestibular nuclear complexes in the turtle Pseudemys scripta elegans were investigated with anterograde tracing. Following injections of 35S-methionine at various locations within the cerebellar and vestibular nuclear complexes, labeled ascending fibers were found to arise from the lateral cerebellar and the rostral (superior and/or dorsolateral) vestibular nuclei. The great majority of these fibers coursed within the ipsilateral ascending periventricular tract. There were possible terminations in the hypothalamosuprapeduncular region, the ovalis-complex, and the nucleus commissuralis anterior, but scarcely any indication of terminal labeling within the dorsal thalamus. The labeled fibers, however, continued rostralward, entered the lateral forebrain bundle, and terminated in the anterior dorsal ventricular ridge--in all but one case, exclusively ipsilaterally. The terminal area within the lateral division (referred to as area L) of the anterior dorsal ventricular ridge was sharply delimited, being situated ventrolateral to the visually oriented area D of the anterior dorsal ventricular ridge (Balaban and Ulinski, '81), medial to the lateral cortex, and ventral to the pallial thickening (motor pallium of Johnston, '16). The findings are compared with related ones in mammals, particularly those pertaining to telencephalic somatosensorimotor regions and their interactions with the vestibular nuclear complex and the cerebellum.

Animals↗
PubMed1985

Mapping of the early neural primordium in quail-chick chimeras. I. Developmental relationships between placodes, facial ectoderm, and prosencephalon.

Defined fragments of the anterolateral neural ridge and of the associated region of the neural plate of presomitic to three-somite stage quail embryos were grafted isotopically and isochronically into chick hosts. This resulted in the development of apparently normal brain and facial structures to which the contribution of the grafted tissue could be observed by means of the quail nuclear marker. It was shown that the anterolateral neural ridge contains the progenitor cells of the adenohypophyseal and olfactory placodes and also of the superficial ectoderm lining the nasal cavity and conchae and the superficial ectoderm of the beak. When the appropriate region of the neural ridge was involved in the quail-chick substitution, the egg tooth was made up of graft-derived cells. Grafting of the neural plate area adjacent to the "ridge" territory containing the placodal ectoderm revealed that the presumptive region of the hypothalamus is in contiguity with that of the adenohypophyseal placode. The same observation was made for the olfactory placode and the floor of the telencephalon from which the olfactive bulb later develops.

Animals↗