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Cortical Plate (cortical + plate)

Distribution by Scientific Domains

Life Sciences	61%
Medical Sciences	38%

Selected Abstracts

Single cause, polymorphic neuronal migration disorders: an animal model

DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 10 2000
Glenn D Rosen PhD
Injury to the developing cortical plate can result in a variety of neuronal migration disorders. The results are reported of experimental research aimed at determining whether these different types of neocortical malformations are the consequence of comparable injury of varying intensity. Freezing probes were placed on the skulls of 44 newborn rats (age equivalent to 4 to 5 months of gestation in humans) and induced either one or two freezing injuries of durations ranging from 2 to 20 seconds. A variety of cortical malformations including minor laminar dysplasias, molecular layer ectopias, microgyria, and porencephalic cysts were seen in the brains of these animals when they were examined on postnatal day (P)2, P21, and P60. The severity of the malformation was directly related to the strength (number of hits and duration) of the freezing injury. These results suggest that a single etiologic event of varying severity during neuronal migration to the neocortex can induce widely disparate malformations of the cortex. [source]

Cortical radial glial cells in human fetuses: Depth-correlated transformation into astrocytes

DEVELOPMENTAL NEUROBIOLOGY, Issue 3 2003
Leonardo C. deAzevedo
Abstract In the human brain, the transformation of radial glial cells (RGC) into astrocytes has been studied only rarely. In this work, we were interested in studying the morphologic aspects underlying this transformation during the fetal/perinatal period, particularly emphasizing the region-specific glial fiber anatomy in the medial cortex. We have used carbocyanine dyes (DiI/DiA) to identify the RGC transitional forms and glial fiber morphology. Immunocytochemical markers such as vimentin and glial fibrillary acidic protein (GFAP) were also employed to label the radial cells of glial lineage and to reveal the early pattern of astrocyte distribution. Neuronal markers such as neuronal-specific nuclear protein (NeuN) and microtubule-associated protein (MAP-2) were employed to discern whether or not these radial cells could, in fact, be neurons or neuronal precursors. The main findings concern the beginning of RGC transformation showing loss of the ventricular fixation in most cases, followed by transitional figures and the appearance of mature astrocytes. In addition, diverse fiber morphology related to depth within the cortical mantle was clearly demonstrated. We concluded that during the fetal/perinatal period the cerebral cortex is undergoing the final stages of radial neuronal migration, followed by involution of RGC ventricular processes and transformation into astrocytes. None of the transitional or other radial glia were positive for neuronal markers. Furthermore, the differential morphology of RGC fibers according to depth suggests that factors may act locally in the subplate and could have a role in the process of cortical RGC transformation and astrocyte localization. The early pattern of astrocyte distribution is bilaminar, sparing the cortical plate. Few astrocytes (GFAP+) in the upper band could be found with radial processes at anytime. This suggests that astrocytes in the marginal zone could be derived from different precursors than those that differentiate from RGCs during this period. © 2003 Wiley Periodicals, Inc. J Neurobiol 55: 288,298, 2003 [source]

Aberrant trajectory of thalamocortical axons associated with abnormal localization of neurocan immunoreactivity in the cerebral neocortex of reeler mutant mice

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2005
Hong-Peng Li
Abstract We examined the molecular mechanisms underlying the formation of the thalamocortical pathway in the cerebral neocortex of normal and reeler mutant mice. During normal development of the mouse neocortex, thalamic axons immunoreactive for the neural cell adhesion molecule L1 rarely invaded the cortical plate and ran centered in the subplate which is immunoreactive for neurocan, a brain-specific chondroitin sulfate proteoglycan. On the other hand, in homozygous reeler mutant mice, thalamic axons took an aberrant course to run obliquely through the cortical plate. Injection of bromodeoxyuridine at embryonic day 11 specifically labeled subplate neurons in normal mice, whilst in the reeler neocortex it labeled cells scattered in the cortical plate as well as in the superficial layer (superplate). Neurocan immunoreactivity was associated with the bromodeoxyuridine-positive cells in the superplate, as well as being present in oblique bands within the cortical plate, along which L1-bearing thalamic axons preferentially ran. The present results support our previous hypothesis proposed for normal rats that a heterophilic molecular interaction between L1 and neurocan is involved in determining the thalamocortical pathway within the neocortical anlage [T. Fukuda et al. (1997)Journal of Comparative Neurology, 382, 141,152]. [source]

A radialization factor in normal cortical plate restores disorganized radial glia and disrupted migration in a model of cortical dysplasia

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003
Thomas A. Hasling
Abstract Treatment of pregnant ferrets on embryonic day 24 (E24) with the antimitotic methylazoxy methanol (MAM) leads to a specific constellation of effects in newborn kits, which include a very thin and poorly laminated neocortex, disruption of radial glial cell morphology with early differentiation into astrocytes, and abnormal positioning of Cajal,Retzius cells. We suggest that MAM treatment on E24 results in this model of cortical dysplasia by eliminating a population of cells that produce a factor capable of maintaining radial glia in their normal morphology. The abnormal radial glia, either alone or in combination with other abnormal features, are likely to prevent proper migration into the cortical plate. To test the possibility that normal cortex can provide the missing substance that influences radial glia, slices of E24 MAM-treated cortex were removed at postnatal day 0 (P0) and cultured adjacent to explants of P0 normal cortical plate. By labelling a small number of cells with injections of fluorescent dextrans into the cultured slices, we found that abnormal radial glia in MAM treated slices cocultured adjacent to normal cortical plate were restored toward normal, in comparison to E24 MAM treated slices cultured alone and in other control conditions. We also found that abnormally positioned Cajal,Retzius cells move into the marginal zone and that neurons are able to migrate into the cortical plate more effectively in the coculture condition. These data indicate that normal cortical plate of ferrets contains a factor causing radial glia to maintain their elongated morphology; the improved position of radial glia encourages repositioning of Cajal,Retzius cells and improved neuronal migration into the cortical plate. [source]

Disabled-1 mRNA and protein expression in developing human cortex

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003
Gundela Meyer
Abstract Disabled-1 (Dab1) forms part of the Reelin,Dab1 signalling pathway that controls neuronal positioning during brain development; Dab1 deficiency gives rise to a reeler-like inversion of cortical layers. To establish a timetable of Dab1 expression in developing human brain, Dab1 mRNA and protein expression were studied in prenatal human cortex. The earliest Dab1 signal was detected at 7 gestational weeks (GW), the stage of transition from preplate to cortical plate, suggesting a role of the Reelin,Dab1 signalling pathway in preplate partition. From 12 to 20 GW, the period of maximum cortical migration, Dab1 expression was prominent in the upper tiers of the cortical plate, to decline after midgestation. Radially orientated apical dendrites of Dab1-expressing neurons indicated a predominant pyramidal phenotype. Pyramidal cells in hippocampus and entorhinal cortex displayed a more protracted time of Dab1 expression compared to neocortex. In addition, at later stages (18,25 GW), Dab1 was also expressed in large neurons scattered throughout intermediate zone and subplate. From 14 to 22 GW, particularly high levels of Dab1 mRNA and protein were observed in cells of the ventricular/subventricular zone displaying the morphology of radial glia. The partial colocalization of vimentin and Dab1 in cells of the ventricular zone supported a radial glia phenotype. The concentration of Dab1 protein in ventricular endfeet and initial portions of radial processes of ventricular-zone cells points to a possible involvement of Dab1 in neurogenesis. Furthermore, a subset of Cajal,Retzius cells in the marginal zone colocalized Dab1 and Reelin, and may thus represent a novel target of the Reelin,Dab1 signalling pathway. [source]

Development of axonal pathways in the human fetal fronto-limbic brain: histochemical characterization and diffusion tensor imaging

JOURNAL OF ANATOMY, Issue 4 2010
Lana Vasung
Abstract The development of cortical axonal pathways in the human brain begins during the transition between the embryonic and fetal period, happens in a series of sequential events, and leads to the establishment of major long trajectories by the neonatal period. We have correlated histochemical markers (acetylcholinesterase (AChE) histochemistry, antibody against synaptic protein SNAP-25 (SNAP-25-immunoreactivity) and neurofilament 200) with the diffusion tensor imaging (DTI) database in order to make a reconstruction of the origin, growth pattern and termination of the pathways in the period between 8 and 34 postconceptual weeks (PCW). Histological sections revealed that the initial outgrowth and formation of joined trajectories of subcortico-frontal pathways (external capsule, cerebral stalk,internal capsule) and limbic bundles (fornix, stria terminalis, amygdaloid radiation) occur by 10 PCW. As early as 11 PCW, major afferent fibers invade the corticostriatal junction. At 13,14 PCW, axonal pathways from the thalamus and basal forebrain approach the deep moiety of the cortical plate, causing the first lamination. The period between 15 and 18 PCW is dominated by elaboration of the periventricular crossroads, sagittal strata and spread of fibers in the subplate and marginal zone. Tracing of fibers in the subplate with DTI is unsuccessful due to the isotropy of this zone. Penetration of the cortical plate occurs after 24,26 PCW. In conclusion, frontal axonal pathways form the periventricular crossroads, sagittal strata and ,waiting' compartments during the path-finding and penetration of the cortical plate. Histochemistry is advantageous in the demonstration of a growth pattern, whereas DTI is unique for demonstrating axonal trajectories. The complexity of fibers is the biological substrate of selective vulnerability of the fetal white matter. [source]

Habitual use of the primate forelimb is reflected in the material properties of subchondral bone in the distal radius

JOURNAL OF ANATOMY, Issue 6 2006
Kristian J. Carlson
Abstract Bone mineral density is directly proportional to compressive strength, which affords an opportunity to estimate in vivo joint load history from the subchondral cortical plate of articular surfaces in isolated skeletal elements. Subchondral bone experiencing greater compressive loads should be of relatively greater density than subchondral bone experiencing less compressive loading. Distribution of the densest areas, either concentrated or diffuse, also may be influenced by the extent of habitual compressive loading. We evaluated subchondral bone in the distal radius of several primates whose locomotion could be characterized in one of three general ways (quadrupedal, suspensory or bipedal), each exemplifying a different manner of habitual forelimb loading (i.e. compression, tension or non-weight-bearing, respectively). We employed computed tomography osteoabsorptiometry (CT-OAM) to acquire optical densities from which false-colour maps were constructed. The false-colour maps were used to evaluate patterns in subchondral density (i.e. apparent density). Suspensory apes and bipedal humans had both smaller percentage areas and less well-defined concentrations of regions of high apparent density relative to quadrupedal primates. Quadrupedal primates exhibited a positive allometric effect of articular surface size on high-density area, whereas suspensory primates exhibited an isometric effect and bipedal humans exhibited no significant relationship between the two. A significant difference between groups characterized by predominantly compressive forelimb loading regimes vs. tensile or non-weight-bearing regimes indicates that subchondral apparent density in the distal radial articular surface distinguishes modes of habitually supporting of body mass. [source]

Microglial colonization of the developing mouse brain: the effect of CD11b deletion

NEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 2 2002
J. K. Jeetle
Introduction:, Microglia are resident mononuclear phagocytes of the central nervous system, which colonize the brain both prenatally and after birth. It is proposed that they enter the brain initially via the surrounding mesenchyme, via ventricles and later through blood vessels, but the mechanisms of entry and signals used for migration are still to be established. Previous studies have shown that ligands for some integrin adhesion molecules expressed on blood vessels in the developing nervous system (particularly ICAM-1 and ICAM-2 which bind CD11a/LFA-1 and CD11b/Mac-1), may act as potential recruiting signals for microglial precursors. This study addressed whether CD11b is influential on the migration of microglial precursors into the developing CNS. Material and methods:,Ricinus communis agglutinin-1 (RCA-1) lectin histochemistry was employed to anatomically map the distribution of amoeboid and ramified microglia from embryonic day 15 (E15) to birth. Embryonic mouse brains from CD11b knockout (,/,) (n = 42), and heterozygote (+/,) (n = 52) mice generated on a C57/BL6 background (Melo et al. Cell Immunol 2000; 205: 13,23) and wild-type (+/+) (n = 37) litter mates were fixed in Bouin's solution, processed to paraffin wax and serially sectioned at 15,40 µm. To investigate further potential signals for recruiting microglial precursors, brains were immunochemically screened for integrins CD11a, CD11b, CD18, ,X, VLA-4 and the chemokine MCP-1. Results:, Microscopic analysis revealed the morphological transition of microglia from predominantly amoeboid forms at E15,E16 to a flourishing population of ramified cells at E19,E20. RCA-1 histochemistry showed no clear differences in microglial distribution or timing of colonization between CD11b (,/,) and wild-type mice from E15 to birth. Although CD11b deletion did not influence the timing of microglial ramification, there appeared to be fewer ramified cells in (,/,) mice within comparative brain regions. This requires further quantitative morphometric analysis. Of the integrins investigated, none were restricted to microglia and only VLA-4 and ,X showed reactivity within the CNS. However, MCP-1 was notably localized to the cortical plate within all genotypes, consistent with previous findings in human foetal CNS (Rezaie & Male. Microsc Res Tech 1999; 45: 359,382). Conclusion:, The results suggest that CD11b has little influence on the timing or regional distribution of microglia in the developing murine CNS. It is more likely that CD11b is only one of several factors that influence the migration and differentiation of these cells. [source]

Distinct roles of neuropilin 1 signaling for radial and tangential extension of callosal axons

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 4 2009
Yumiko Hatanaka
Abstract Cortical excitatory neurons migrate from their origin in the ventricular zone (VZ) toward the pial surface. During migration, these neurons exhibit a stellate shape in the intermediate zone (IZ), transform into bipolar cells, and then initiate radial migration, extending a trailing process, which may lead to an axon. Here we examined the role of neuropilin 1 (NRP1) in these developmental events. Both NRP1 mRNA and protein were highly expressed in the IZ, where stellate-shaped cells were located. DiI labeling experiments showed that neuronal migration occurred normally in Nrp1 mutant mice up to embryonic day (E) 14.5, the latest day to which the mutant survives, with only subtle axonal defasciculation. However, interference with Nrp1 signaling at a later stage caused pathfinding errors: when a dominant negative form of Nrp1 was electroporated into the cortical VZ cells at E12.5 or E15.5 and examined perinatally, guidance errors were found in tangential axonal extension toward the midline. In contrast, no significant effect was noted on the migration of cortical excitatory neurons. These findings indicate that NRP1 plays an important role in the guidance of callosal axons originating from cortical excitatory neurons but does not support a role in their migration. Moreover, insofar as radial axonal extension within the cortical plate was unaffected, the present findings imply that molecular mechanisms for the axonal extension of excitatory neurons within the cortical plate are distinct from those in the white matter. J. Comp. Neurol. 514:215,225, 2009. © 2009 Wiley-Liss, Inc. [source]

Distinct migratory behavior of early- and late-born neurons derived from the cortical ventricular zone

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2004
Yumiko Hatanaka
Abstract Time-lapse studies indicate that ventricular zone (VZ)-derived cells show two migratory modes in the cerebral cortex at different stages of mammalian embryogenesis: somal translocation and locomotion. We carried out a systematic analysis to examine whether the migratory behavior of cortical neurons derived from the cortical VZ is stage-dependent. We labeled VZ cells of mouse embryos with green fluorescent protein (gfp) -encoding plasmids by in utero electroporation and evaluated the labeled cells after appropriate survival periods. After electroporation at either embryonic day (E) 12.5 or E15.5, GFP+ VZ cells were initially spindle-shaped and radially oriented. After leaving the VZ, they transformed into round or horizontally oriented fusiform neurons with many short processes. They then seemed to gradually change into radially oriented bipolar cells as they moved upward. Whereas the earliest emigrants from the VZ labeled at E12.5 (early-born neurons) reached the top of the cortical plate (CP) after these changes, VZ cells labeled at E15.5 (late-born neurons) further migrated along the length of radial fibers to reach the top of the CP. A dominant negative form of the gene for cyclin-dependent kinase 5 (Cdk5DN) was then introduced into VZ cells. Transfection of E12.5 VZ with cdk5dn did not disrupt the migration of the early-born neurons. However, this caused a failure in migration of the late-born neurons, although they transformed into bipolar shapes in the intermediate zone. Thus, there appear to be at least two distinct migratory phases of cortical neurons: one common to the early- and late-born neurons, and the other specific to late-born neurons and Cdk5-dependent. J. Comp. Neurol. 479:1,14, 2004. © 2004 Wiley-Liss, Inc. [source]

The development of the subplate and thalamocortical connections in the human foetal brain

ACTA PAEDIATRICA, Issue 8 2010
Ivica Kostovi
Abstract The aim of this review is to present clinically relevant data on prenatal development of thalamocortical connections in the human brain. The analysis is based on extensive Zagreb Neuroembryological Collection, including more than 500 prenatal human brains stained with various classical neurohistological, as well as modern histochemical and immunohistochemical methods. The connection of thalamocortical axons during the ,waiting' period with transient cortical subplate zone and subsequent synaptic engagement in the cortical plate is the main connectivity event in the late foetus and preterm infant. This connectivity is the structural substrate for the endogeneous subplate and sensory-driven circuitry generating transient electrical phenomena and may represent a transient network in the developmental history of consciousness. Conclusion:, Findings presented in this review should be considered in the management of pain in preterm infants, in searching for the vulnerability of the subplate zone in diagnostic procedures using the in vivo MRI and in revealing the developmental origin of cognitive and mental disorders. [source]

Surgical advantages with ITI TE® implants placement in conjunction with split crest technique

CLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2005
18-month results of an ongoing prospective study
Abstract: Implant rehabilitation of the edentulous maxilla may be somewhat problematic because of anatomic situations involving insufficient bone thickness. One approach in this situation is localized ridge augmentation with the split crest technique. This surgical approach allows the external cortical plate of the maxilla to be moved in a labial direction to gain an increase in width to introduce implants of appropriate diameter. This ongoing prospective study evaluated: (i) the surgical advantages that the new ITI TE® implants have showed compared with the ITI standard solid-screw implants when placed in conjunction with the split crest technique and (ii) the implant success rate associated with 42 ITI TE® implants and 40 ITI standard solid-screw implants placed in 40 patients in conjunction with the split crest technique. ITI TE® implants have shown direct and indirect advantages in reducing the risk of fracture of the labial cortical plate during all the three fundamental surgical steps of this technique: (a) the ridge expansion with osteotomes; (b) implant site preparation with drills and (c) implant insertion. The overall success rates of ITI TE® implants and standard screw implants were 100% and 95%, respectively. Based on the preliminary results of the present study, it can be concluded that ITI TE® implants inserted in conjunction with split crest technique seem to be a promising surgical procedure to treat selected anatomic situations involving insufficient maxillary bone thickness. Résumé La réhabilitation implantaire du maxillaire édenté peut être problèmatique à cause des situations anatomiques comportant une insuffisance de l'épaisseur osseuse. Une approche de cette situation est d'effectuer un épaississement du rebord localisé avec la technique du rebord osseux fendu. Cette approche chirurgicale permet au plateau cortical externe du maxillaire d'être déplacé en une direction linguale pour augmenter la largeur afin de pouvoir ensuite placer des implants d'un diamètre approprié. Cette étude prospective encore en cours a évalué 1) les avantages chirurgicaux des nouveaux implants ITI TE comparés aux implants ITI en vis solide ITI standard lorsqu'ils étaient placés en association avec cette technique de rebord osseux fendu et 2) le taux de succès implantaire associé avec 42 implants ITI TE et 40 implants vis solides ITI standard placés chez 40 patients en association avec cette technique de rebord osseux fendu. Les implants ITI TE ont montré des avantages directs et indirects en réduisant le risque de fracture de la corticale linguale durant les trois étapes chirurgicales fondamentales de cette technique : a) l'expansion du rebord alvéolaire avec les ostétomes, b) la préparation des sites implantaires avec les forets et c) l'insertion implantaire. Les taux de succès généraux des implants ITI TE et des implants vis standards étaient respectivement de 100 % et 95%. Basé sur le résultat préléminaire de cette étude, il peut être conclu que les implants ITI TE insérés en association avec la technique du rebord osseux fendu semble être un processus chirurgical prometteur pour traiter des situations anatomiques sélectionnées qui comportent une épaisseur osseuse insuffisante du maxillaire. Zusammenfassung Die Rekonstruktion einer zahnlosen Situation im Oberkiefer ist dann etwas problematischer, wenn anatomisch ungünstige Gegebenheiten wie zum Beispiel eine ungenügende vertikale Breite des Alveolarknochens besteht. Eine mögliche Vorgehensweise in dieser Situation ist die lokale Knochenaugmentation mittels Spaltung und Spreizung der Knochenkortikalis. Diese chirurgische Methode erlaubt uns, die äussere Kortikalis des Oberkiefers in labialer Richtung abzuspreizen und somit ein genügend breites Knochenbett zu erhalten, um Implantate mit dem geeigneten Durchmesser setzen zu können. Diese noch weiterverfolgte Langzeitstudie untersuchte: (i) die chirurgischen Vorteile, die uns das neue ITI TE-Implantat verglichen mit der Vollschraube des ITI-Standardimplantates in Verbindung mit der Kortikalisspreiztechnik bringt und (ii) die Implantaterfolgsrate von 42 ITI TE-Implantaten und 40 Vollschrauben der ITI-Standartimplantate, die man bei 40 Patienten in Verbindung mit der Kortikalisspreiztechnik gesetzt hat. Die ITI TE-Implantate zeigten direkte und indirekte Vorteile bei der Verminderung des Frakturrisikos in der labialen Kortikalisplatte während den drei grundlegenden Schritten dieser Technik: (a) Spreizung des Knochenkamms mit Osteotomen; (b) Vorbohren des Implantatbettes und (c) Eindrehen der Implantate. Die Erfolgsrate lag bei den ITI TE-Implantaten bei 100% und bei den Standartschraubenimplantaten bei 95%. Basierend auf diesen ersten Resultaten der Studie kann man schliessen, dass es sich bei ITI TE-Implantate, die in Verbindung mit der Kortikalisspreiztechnik eingesetzt worden waren, um eine vielversprechende chirugische Technik handelt, um ausgewählte anatomische Situationen, wie zu Beispiel eine ungenügende vertikale Breite des Alveolarknochens im Oberkiefer, zu behandeln. Resumen La rehabilitación con implantes del maxilar edéntulo puede ser un tanto problemática debido a situaciones anatómicas que comprenden situaciones de grosor óseo insuficiente. Un enfoque en esta situación, es el aumento localizado de la cresta con la técnica de cresta dividida. Este enfoque quirúrgico permite mover la placa cortical externa del maxilar en dirección labial para ganar un aumento en anchura para introducir implantes del diámetro apropiado. Este estudio prospectivo continuado evaluó: i) los avances quirúrgicos que los nuevos implantes ITI TE han mostrado en comparación con los implantes macizos roscados ITI estándar al colocarse en combinación con la técnica de cresta dividida y ii) el índice de éxito del implante asociado con 42 implantes ITI TE y 40 implantes macizos roscados estándar colocados en 40 pacientes en combinación con la técnica de cresta dividida. Los implantes ITI TE han mostrado ventajas directas e indirectas en reducir el riesgo de fractura de la placa cortical labial durante los tres pasos quirúrgicos fundamentales de esta técnica: a) expansión de la cresta con osteotomos; b) preparación del lecho implantario con fresas y c) inserción del implante. El índice total de éxito de los implantes ITI TE y de los implantes estándar roscados fue del 100% y del 95% respectivamente. Basado en los resultados preliminares del presente estudio, se puede concluir que los implantes ITI TE insertados en combinación con la técnica de cresta dividida parece ser un procedimiento quirúrgico prometedor para tratar situaciones anatómicas determinadas que conllevan un grosor óseo maxilar insuficiente. [source]

Bone morphology and vascularization of untreated and guided bone augmentation-treated rabbit calvaria: evaluation of an augmentation model

CLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2005
Christer Slotte
Abstract Objectives: Cranial vault is widely used in experimental models on membranous bone healing in general, guided bone augmentation (GBA) studies being one example. To our knowledge, however, few studies on the characteristics of the untreated calvaria regarding bone density, vessel topography, and their intra/interindividual variations and associations are available. The aims of this investigation were to (1) map the large vessel topography of the skull vault, (2) describe the parietal bones of the adult rabbit histologically and morphometrically, and (3) histologically compare untreated parietal bone with parietal bone that had been treated with a GBA device. Material and methods: Ten adult untreated rabbits were microangiographed. General anesthesia was induced and the mediastinum was opened. Heparin and lidocaine were injected in the aorta followed by perfusion with India ink. After death, en bloc biopsies of the skull vault including the overlying soft tissues and dura mater were taken. The specimens were cleared with the Spalteholtz technique, microscopically examined, and digitally imaged. Thereafter, circular biopsies were harvested to obtain decalcified sections. In addition, sections from 14 GBA-treated rabbit skulls (of the same race, sex and age as the untreated animals) served as reference specimens for comparison. Histomorphometric examinations were carried out. Results: In the cleared specimens, all parietal bones were found to be supplied by one major branch of the meningeal artery. From each of these, separate branches supplied the dura wherein a fine vessel network covered the bone. No major vessels were found in the supracalvarial soft tissue. Numerous fine vessels were found within the periosteum and dura entering the cortical plates. The decalcified sections of the parietal bones revealed an outer and inner cortical plate enveloping a diploic space containing bone trabeculae, marrow tissue and larger sinusoids. Hollow connections were frequently found in both the outer and inner cortical plates in both the untreated and the GBA-treated specimens. These connections contained marrow tissue that extended to the periosteum and the dura. The morphometric measurements revealed similar proportions of cortical, trabecular, and marrow areas in the right and left untreated bones. The area of the outer cortical plate was significantly larger than the area of the inner cortical plate. Bone density was similar in the right and left untreated and GBA-treated specimens, as was the frequency and width of hollow connections through the cortical bone plates. Conclusions: The symmetry between the left and right parietal bones concerning the large vessel topography and the histomorphometric parameters assessed was high. Hollow connections in the cortical plates were frequently found. The bilateral use of the parietal bones is suggested to be reliable in experimental GBA models regarding the blood supply and bone quality. Résumé La voûte crânienne est souvent utilisée dans les modèles expérimentaux de guérison osseuse membranaire en général, l'augmentation osseuse guidée (GBA) étant un exemple. Peu d'études sur les crânes non-traités sont disponibles en ce qui concerne la densité osseuse, la topographie des vaisseaux et leurs variations intra/interindividuelles et leurs associations. Les buts de cette étude ont été 1) de cartographier la topographie des vaisseaux larges sur la voute crânienne, 2) de décrire les os pariétaux du lapin adulte histologiquement et morphométriquement et 3) de comparer histologiquement l'os pariétal non-traité avec celui traité par GBA. Dix lapins adultes non-traités ont subi une micro-angiographie. L'anesthésie générale a été effectuée et la partie médiane a été ouverte. De l'héparine et de la lidocaïne ont été injectées dans l'aorte suivies d'une perfusion avec de l'encre noire. Après la mort, des biopsies en blocs de la voûte crânienne comportant la dura mater et les tissus mous la recouvrant ont été prélevées. Les spécimens ont été estimés par la technique de Spalteholtz, examinés microscopiquement et des images digitales ont été réalisées. Des biopsies circulaires ont été prélevées pour obtenir des sections décalcifiées. Des sections de 14 crânes de lapins traités GBA (de même race, sexe et âge que les non-traités) ont servi de spécimens de référence pour comparaison. Des examens histomorphométriques ont été effectués. Dans les spécimens non-traités, tous les os pariétaux étaient irrigués par une branche majeure de l'artère méningée. De chacune de ces dernières, différentes branches abreuvaient la dura dans laquelle un réseau de vaisseau fins recouvrait l'os. Aucun vaisseau majeur n'a été trouvé dans le tissu mou ou sus-voûte. De nombreux vaisseaux fins ont été trouvés à l'intérieur du périoste et de la dura pénétrant qu'entre les bords corticaux. Les sections décalcifiées des os pariétaux ont révélé des bords corticaux interne et externe enveloppant un espace diploïque contenant de l'os trabéculaire, de la moelle osseuse et de larges sinusoïdes. Des connexions creuses étaient fréquemment trouvées tant dans les plaques corticales interne qu'externe et tant dans les spécimens non-traités que traités GBA. Ces connexions contenaient de la moelle qui allait jusqu'au périoste et la dura. Les mesures morphométriques ont révélé des proportions semblables de cortical, trabécules et moelle dans les les os non-traités. L'aire du bord cortical externe était significativement plus importante que l'aire du bord cortical interne. La densité osseuse était semblable dans les spécimens non-traités et traités GBA gauches et droits ainsi que la fréquence et la largeur des connexions creuses à travers les bords osseux corticaux. La symétrie entre les os pariétaux gauches et droits concernant la topographie des vaisseux larges et des paramètres histomorphométriques étaient importante. Les connexions creuses dans les bords corticaux était souvent trouvées. L'utilisation bilatérale des os pariétaux est proposée pour sa fiabilité dans les modèles GBA expérimentaux concernant l'apport sanguin et la qualité osseuse. Zusammenfassung Ziele:,Die Schädeldecke wird oft bei experimentellen Modellen zur bindegewebigen Knochenheilung verwendet. Ein Beispiel dafür sind Studien zur gesteuerten Knochenaugmentation (GBA). Soviel wir wissen, existieren jedoch nur wenige Studien über die Charakteristiken der unbehandelten Kalvaria bezüglich Knochendichte, Gefässtopographie und deren intra-/interindividuelle Variationen und Assoziationen. Die Ziele dieser Untersuchung waren (1) die Topographie der grossen Gefässe der Schädeldecke aufzuzeichnen, (2) die parietalen Knochen des ausgewachsenen Kaninchens histologisch und histomorphometrisch zu beschreiben, und (3) histologisch den unbehandelten parietalen Knochen mit parietalem Knochen, der mit einer GBA Einrichtung behandelt worden war, zu vergleichen. Material und Methoden:,Zehn ausgewachsene Kaninchen wurden mikroangiographisch untersucht. In Narkose wurde das Mediastinum eröffnet. Es wurde Heparin und Lidocain in die Aorta injiziert, darauf folgte die Perfusion mit India Tinte. Nach dem Tod wurden Blockbiopsien der Schädeldecke inklusive bedeckende Weichgewebe und Dura mater entnommen. Die Präparate wurden mittels der Spaltenholztechink gereinigt, mikroskopisch untersucht und digital aufgezeichnet. Danach wurden zirkuläre Biopsien gewonnen, um entkalkte Schnitte herzustellen. Zusätzlich dienten Schnitte von 14 GBA-behandelten Kaninchenschädeln (gleiche Rasse, Geschlecht und Alter wie die unbehandelten Tiere) als Referenzpräparate zum Vergleich. Es wurden histomorphometrische Untersuchungen durchgeführt. Resultate:,In den gereinigten Präparaten konnte gesehen werden, dass alle parietalen Knochen durch einen grossen Ast der Meningalarterie versorgt wurden. Separate Aeste dieser Arterie versorgten die Dura, wobei ein feines Gefässnetz den Knochen bedeckte. In den Weichgeweben auf der Kalvaria konnten keine grossen Gefässe gefunden werden. Im Periost und in der Dura waren zahlreiche feine Gefässe zu sehen, welche in die kortikalen Platten eintraten. Die entkalkten Schnitte der parietalen Knochen zeigten eine äussere und innere kortikale Platte, welche einen abgeschlossenen Raum mit Knochentrabekeln, Markgewebe und grossen Hohlräumen umschlossen. In der inneren und in der äusseren kortikalen Platte konnten oft sowohl bei den unbehandelten als auch bei den GBA-behandelten Präparaten hohle Verbindungen gefunden werden. Diese Verbindungen enthielten Markgewebe, dass sich bis zum Periost und der Dura erstreckte. Die morphometrischen Messungen zeigten sowohl in den rechten als auch in den linken unbehandelten Knochen ähnliche Proportionen zwischen kortikalem Knochen, trabekulärem Knochen und den Markarealen. Die Fläche der äusseren kortikalen Platte war signifikant grösser als die Fläche der inneren kortikalen Platte. Die Knochendichte war in den rechten und linken unbehandelten und in den GBA-behandelten Präparaten ähnlich, ebenso die Häufigkeit und die Breite der hohlen Verbindungen durch die kortikalen Platten. Schlussfolgerungen:,Die Symmetrie zwischen den rechten und linken parietalen Knochen bezüglich Topographie der grossen Gefässe und der untersuchten histomorphometrischen Parameter war gross. In den kortikalen Platten konnten häufig hohle Verbindungen gefunden werden. Es wird vorgeschlagen, dass die bilaterale Verwendung von parietalen Knochen bei experimentellen GBA-Modellen zuverlässig ist bezüglich Blutversorgung und Knochenqualität. Resumen Objetivos:,La bóveda craneal es ampliamente usada en modelos experimentales en cicatrización de hueso membranoso en general, siendo un ejemplo los estudios de regeneración ósea guiada (GBA). Que sepamos, sin embargo, se dispone de pocos estudios sobre las características del calvario no tratado con respecto a la densidad ósea, la topografía vascular, y sus variaciones intra/interindividuo y sus asociaciones. Las intenciones de esta investigación fueron (1) cartografiar la topografía de grandes vasos de la bóveda craneal, (2) describir histológica y morfométricamente los huesos parietales del conejo adulto, y (3) comparar histológicamente el hueso parietal no tratado con el hueso parietal tratado con un dispositivo de GBA. Material y Métodos:,Se llevaron a cabo microangiografías a diez conejos adultos sin tratar. Se indujo anestesia general y se abrió el mediastino Se inyectaron heparina y lidocaina en la aorta seguida por infusión de tinta de India. Tras la muerte, se tomaron biopsias en bloque de la bóveda craneal incluyendo los tejidos blandos superpuestos y de la duramadre. Los especimenes se aclararon con la técnica de Spalteholtz, se examinaron microscópicamente, y se tomaron imágenes digitales. Más adelante, se recogieron biopsias circulares para obtener secciones descalcificadas. Además, secciones de los cráneos de los conejos tratados con 14secciones descalcificadas. Además, secciones de los cráneos de los conejos tratados con 14 GBA (de la misma raza, sexo y edad que los animales no tratados) sirvieron como especimenes de referencia para la comparación. Se llevaron a cabo exámenes histomorfométricos. Resultados:,En los especimenes aclarados, todos los huesos parietales se encontró que estaban irrigados por una rama principal de la arteria meníngea. De cada una de estas, ramas separadas irrigaron la dura en donde una fina red de vasos cubrió el hueso. No se encontraron vasos mayores en el tejido blando supracalvario. Se encontraron numerosos vasos dentro del periostio y la dura entrando en las placas corticales. Las secciones descalcificadas de los huesos parietales revelaron una placa cortical interna y externa envolviendo un espacio diploico conteniendo trabéculas óseas, tejido medular y grandes sinusoides. Frecuentemente se encontraron conexiones huecas en las placas corticales internas y externas tanto en los especimenes sin tratar como en los tratados con GBA. Estas conexiones contenían tejido medular que se extendió hasta el periostio y la dura. Las medidas morfogenéticas revelaron proporciones similares de áreas corticales trabeculares y medulares en los huesos derecho e izquierdo no tratados. El área de la placa cortical externa fue significativamente mayor que el área de placa cortical interna. La densidad ósea fue similar en el lado derecho e izquierdo no tratados y en los especimenes tratados con GBA, así como la frecuencia y la anchura de las conexiones huecas a lo largo de las placas óseas corticales. Conclusiones:,La simetría entre los huesos parietales izquierdos y derechos concernientes a la topografía vascular y los parámetros histomorfométricos valorados fue alta. Las conexiones huecas en las placas corticales se encontraron con frecuencia. Se sugiere que el uso bilateral de huesos parietales es fiable como modelo experimental GBA respecto al suministro de sangre y calidad ósea. [source]

Phenotypic differences in the brains and limbs of mutant mice caused by differences of Gli3 gene expression levels

CONGENITAL ANOMALIES, Issue 2 2001
Ichiro Naruse
ABSTRACT, The genetic polydactyly/arhinencephaly mouse, Pdn/Pdn, exhibits severe polydactyly both in the fore-and hindlimbs, agenesis of the olfactory bulbs, corpus callosum, anterior commissure, and hydrocephalus. A candidate gene for the Pdn mouse has been speculated to be Gli3, because Pdn has been considered to be an allele of Xt whose responsible gene has been clarified to be Gli3. Recently, it has been cleared that retro-transposons are inserted into nitron 3, upstream of zinc finger domain, of the Gli3 gene in the Pdn mouse, resulting to the severe suppression of Gli3 gene expression in Pdn/Pdn embryos. Meanwhile, XtJ/XtJ mice exhibit more severe polydactyly than that of Pdn/Pdn. Arhinencephaly and microholoprosencephaly including agenesis of the olfactory bulbs, corpus callosum, anterior commissure, hippocampal commissure, habenular commissure, and posterior commissure, and moreover, the cerebral cortical plates and hippocampus are not formed in the XtJ/XtJ mice. The XtJ/XtJ mouse has a large deletion in Gli3 structural gene and shows null expression. From these corroborations, we speculated that the differences in the Gli3 gene expression levels resulted in the phenotypic differences between the Pdn/Pdn and XtJ/XtJ mice. [source]