Origin matters: Differences in embryonic tissue origin and Wnt signaling determine the osteogenic potential and healing capacity of frontal and parietal calvarial bones

Calvarial bones arise from two embryonic tissues, namely, the neural crest and the mesoderm. In this study we have addressed the important question of whether disparate embryonic tissue origins impart variable osteogenic potential and regenerative capacity to calvarial bones, as well as what the underlying molecular mechanism(s). Thus, by performing in vitro and in vivo studies, we have investigated whether differences exist between neural crest–derived frontal and paraxial mesodermal–derived parietal bone. Of interest, our data indicate that calvarial bone osteoblasts of neural crest origin have superior potential for osteogenic differentiation. Furthermore, neural crest–derived frontal bone displays a superior capacity to undergo osseous healing compared with calvarial bone of paraxial mesoderm origin. Our study identified both in vitro and in vivo enhanced endogenous canonical Wnt signaling in frontal bone compared with parietal bone. In addition, we demonstrate that constitutive activation of canonical Wnt signaling in paraxial mesodermal–derived parietal osteoblasts mimics the osteogenic potential of frontal osteoblasts, whereas knockdown of canonical Wnt signaling dramatically impairs the greater osteogenic potential of neural crest–derived frontal osteoblasts. Moreover, fibroblast growth factor 2 (FGF‐2) treatment induces phosphorylation of GSK‐3β and increases the nuclear levels of β‐catenin in osteoblasts, suggesting that enhanced activation of Wnt signaling might be mediated by FGF. Taken together, our data provide compelling evidence that indeed embryonic tissue origin makes a difference and that active canonical Wnt signaling plays a major role in contributing to the superior intrinsic osteogenic potential and tissue regeneration observed in neural crest–derived frontal bone. © 2010 American Society for Bone and Mineral Research     

Attentional functions of parietal and frontal cortex

A model of normal attentional function, based on the concept of competitive parallel processing, is used to compare attentional deficits following parietal and frontal lobe lesions. Measurements are obtained for visual processing speed, capacity of visual short-term memory (VSTM), spatial bias (bias to left or right hemifield) and top-down control (selective attention based on task relevance). The results show important differences, but also surprising similarities, in parietal and frontal lobe patients. For processing speed and VSTM, deficits are selectively associated with parietal lesions, in particular lesions of the temporoparietal junction. We discuss explanations based on either grey matter or white matter lesions. In striking contrast, measures of attentional weighting (spatial bias and top-down control) are predicted by simple lesion volume. We suggest that attentional weights reflect competition between broadly distributed object representations. Parietal and frontal mechanisms work together, both in weighting by location and weighting by task context.     

Function of parietal and frontal shunts in childhood hydrocephalus

This study was performed to determine if cerebrospinal fluid (CSF) shunts inserted via the frontal and parietal regions function for similar lengths of time. The medical records of 114 children with CSF shunts were reviewed. In 83 of these cases computerized tomography scans were also available. Ninety percent of the operations were to insert the child's first shunt. The site of insertion, cause of hydrocephalus, patient's age, surgeon, duration of function (time from insertion to malfunction or to latest follow-up evaluation), presence of infection, catheter location within the ventricle, and duration of function of the subsequent shunt were recorded. Data were analyzed by the chi-square, logistic regression, and life-table methods. Shunts had been inserted via the frontal route in 62 children and via the parietal route in 52. The children's ages, causes of hydrocephalus, and infection rates were similar in both groups. Duration of shunt function was predicted by the site of shunt insertion and the catheter position within the ventricles: shunts inserted via the frontal region functioned significantly longer than parietally inserted shunts, both as the initial shunt (Wilcoxon, p = 0.0008) and after a malfunction, and catheters positioned within the ipsilateral frontal horn functioned significantly longer than those in other ventricular locations (Wilcoxon, p = 0.03).     

The biology of bones and of bone fracture healing

For the treatment of fractures several systems are available. Biological and biomechanical aspects have to be considered in order to obtain an optimal final result. The vascular supply of the intact and of the fractured bone is reviewed. The role of the fracture hematoma with a low pO2 and a pH below the physiological range are discussed. In bone remodelling tension forces and cyclic loading are important factors in resorption and regeneration. The influence of the periosteum in bone healing after internal fixation is described.     

Concerning the similarities between three alkaline phosphatases of human foetal parietal bones

Three alkaline phosphatases (I, II, and III), partially purified from human foetal parietal bones, were similarly active in identical conditions. The substrate constant,K _s, for the hydrolysis of a given substrate (-glyceryl phosphate, DL--glyceryl phosphate, glucose 1-phosphate. and p-nitrophenyl phosphate) was approximately the same for each of the enzymes studied, The values ofK _s for the first three substrates above were 0.08, 0.23, and 0.19 mM, respectively for all enzymes. For p-nitrophenyl phosphate the values were 0.029, 0.033, and 0.046 mM, for I, II, and III, respectively. The effect of several divalent metal cations, EDTA, phenylmethanesulphonyl fluoride,p-chloromercuribenzoate, N-ethylmaleimide, and other reagents was the same for all enzymes. Mg²⁺ and Ca²⁺ ions produced the highest rate of hydrolysis ofp-nitrophenyl phosphate. Phenylmethanesulphonyl fluoride inhibited non-competitively all enzymes (K _i=0.07 mM for I and II, and 0.05 mM for III). EDTA inhibited all enzymes, butp-chloromercuribenzote and N-ethylmaleimide caused no effect. L-Cystine inhibited noncompetitively all three phosphatases withK _i close to 0.02 mM for I, II, and III. The effect of quaternary ammonium compounds differed for each enzyme, -lecithin producing the strongest activation and phosphocholine inhibition in all cases. The differences were considered as physical properties, whereas the similarities were considered as substrate-binding and catalytic properties. The three enzymes were regarded as different phosphatases.

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Zusammenfassung Drei aus foetalen menschlichen Parietalknochen teilweise gereinigte alkalische Phosphatasen (I, II und III) waren gleicherweise, aktiv unter identischen Bedingungen. Die Substratkonstante,K _s, für die Hydrolyse eines gegebenen Substrates (-glycerylphosphat, DL--glycerylphosphat, Glucose-1-Phosphat undp-Nitrophenylphosphat) war annähernd dieselbe für jedes der untersuchten Enzyme. DieK _s-Werte für die ersten drei der obgenannten Substrate betrugen jeweils 0,08; 0,23 und 0,19 mM für alle Enzyme. Fürp-nitrophenylphosphat lagen die Werte jeweils bei 0,029; 0,033 und 0,046 mM. Die Wirkung von verschiedenen zweiwertigen Metallkationen (EDTA, Phenylmethansulfonylfluorid,p-Chloromercuribenzoat, N-Aethylmaleinimid und andere Reagenzien) war dieselbe für alle Enzyme. Mg²⁺-und Ca²⁺-Ionen bewirkten die größte Hydrolysegeschwindigkeit vonp-Nitrophenylphosphat. Phenylmethansulfonylfluorid hemmte alle Enzyme nicht kompetitiv (K _i=0,07 mM für I und II, und 0,05 mM für III). Alle Enzyme wurden durch EDTA gehemmt;p-Chloromercuribenzoat und N-Aethylmaleinimid hatten jedoch keine Wirkung. L-Cystin M hemmte alle drei Phosphatasen nicht kompetitiv mit einemK _i von annähernd 0,02 mM für I, II und III. Die Wirkung quaternärer Ammoniumverbindungen war für jedes Enzym verschieden, wobei -Lecithin die stärkste Aktivierung, Phosphocholin in allen Fällen eine Hemmung hervorrief. Die Unterschiede erschienen als physikalische Eigenschaften, während die Ähnlichkeiten als substratbindende und katalytische Eigenschaften angesehen wurden. Die 3 Enzyme wurden als verschiedene Phosphatasen betrachtet.

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Résumé Trois phosphatases alcalines (I, II et III), partiellement purifiées, d'os pariétal humain ftal, sont également actives dans des conditions identiques. La constante de subtratK _s, pour l'hydrolyse d'un substrat donné (-glyceryl phosphate, DL--glycery. phosphate, glucose-1-phosphate, etp-nitrophenyl phosphate) est approximativement la même pour chaque enzyme, étudiée. Les valeurs deK _s pour les trois premiers substrats, mentionnés ci-dessus, sont respectivement de 0.08, 0.23 et 0.19 mM pour chaque enzyme. Pourp-nitrophenyl phosphate, les valeurs sont 0.029, 0.033 et 0.046 mM pour I, II, III respectivement. L'effet de plusieurs cations métalliques divalents, de l'EDTA, du fluorure de phenylmethanesulphonyle, dep-chloromercuribenzoate, de N-ethylmaleimide et d'autres réactifs est identique pour chaque enzyme. Mg²⁺ produisent l'hydrolyse le plus accentuée dup-nitrophenyl phosphate. Le fluorure de phenylmethane sulphonyle inhibe, de façon non compétitive, toutes les enzymes (K _i=0.07 mM pour I et II, et 0.05 mM pour III). L'EDTA inhibe chaque enzyme, maisp-chloromercuribenzoate et N-ethylmaleimide n'ont aucun effet. L-cystine M inhibe, de façon non compétitive, les trois phosphatases avecK _i près de 0.02 mM pour I, II et III. L'effet, de composés d'ammonium quaternaires est différent pour chaque enzyme: -Lècithine active le plus et la phosphocholine inhibe le plus. Les différences paraissent liéer aux propriétés physiques, alors que les similitudes paraissent liées aux propriétès catalytiques et aux substrats. Les trois enzymes sont considérées comme des phosphatases différentes.

     

Agenesis of parietal bones with restoration of the cranial vault. Case report.

Complete agenesis of both parietal bones was found as a single anomaly in an otherwise healthy boy. The defect in the cranial vault was restored with performed methyl methacrylate onlay plates.     

Lipid changes in the bones of the healing vitamin D-deficient phosphate-deficient rat

The bones of vitamin D-deficient, phosphate-deficient rats have a lipid composition that is significantly different from that of normal bones. Specifically, these bones have elevated cholesterol and reduced lysophosphatide and free fatty acid contents. Treatment of these animals with a single dose of vitamin D and phosphate produces healing within 72 h and causes rapid corrections of alterations in growth plate and cancellous bone lipid composition. Healing of the rachitic/osteomalacic state in these animals was demonstrated radiographically and histologically. Histomorphometric measurements showed that the relative osteoid volume of the cancellous bone rapidly approached the 7% value of normal controls, decreasing from 29% in the rachitic animals to 16% by 12 h and 8.5% by 72 h. Significant changes in ash weight, Ca:P ratio, and crystal-lite size and perfection were detectable at 12 h, with these parameters approaching values found in normal animals within 72 h. Calcium-acidic phospholipid-phosphate complexes, which are known to promote hydroxyapatite formation, peaked in concentration at 12 h in epiphysis, cancellous, and cortical bone, returning rapidly to normal values after that time. In untreated animals the complexed acidic phospholipid content of the nonmineralized epiphysis was comparable to that in normal mineralizing epiphysis, whereas the content of the complexes was reduced in the cancellous bones of the untreated animals.     

创面愈合过程中内源性EGF变化的研究

为探讨创面愈合的机理，本实验采用免疫组织化学方法，对大鼠中厚皮片供皮区创面愈合过程中第４、８、１２和１６天创面内源性表皮生长因子（Ｅｐｉｄｅｒｍａｌｇｒｏｗｔｈｆａｃｔｏｒ，ＥＧＦ）的变化进行了研究。结果表明，创面愈合过程中内源性ＥＧＦ含量表现有规律性变化，以伤后第８天含量最多，伤后早期和晚期次之，创面愈合后其含量进一步减少。结论：创面愈合过程中，内源性ＥＧＦ的变化促进了创面愈合，是创面愈合的机理之一，结合内源性ＥＧＦ变化，合理外用ＥＧＦ对创面愈合可能会取得促进的效果。     

创面愈合过程中内源性FGF含量变化的研究

为探讨创面愈合的机制，本实验通过免疫组织化学方法，对大鼠断层供皮区创面愈合过程中伤后４天，８天，１２天和１６天创面内源性成纤维细胞生长因子（ＦｉｂｒｏｂｌａｓｔＧｒｏｗｔｈＦａｃｔｏｒ．ＦＧＦ）变化进行了研究。结果表明：创面愈合过程中内源性ＦＧＦ有规律性变化，以伤后８天时相对含量最多，伤后早期和伤后晚期次之，创面愈合后其内源性含量进一步减少。结论：创面愈合过程中，内源性ＦＧＦ的变化促进了创面愈合，是创面愈合的机制之一，结合内源性ＦＧＦ变化，合理外用ＦＧＦ对促进创面愈合可能会取得更好的效果。     

酸性成纤维细胞生长因子及表皮生长因子对兔韧带细胞增殖的影响

目的：观察酸性成纤维细胞生长因子(aFGF)和表皮生长因子(EGF)对内侧副韧带(MCL)和前十字韧带(ACL)细胞增殖行为的影响。方法：培养10周龄新西兰白兔内侧副韧带和前十字韧带细胞，在培养液中分别加入aFGF和EGF，以XTT方法测定细胞的增殖行为。结果：aFGF在1ng／ml时即对两种细胞具有显著的促进增殖作用，其浓度达50ng／ml时，对MCL细胞的促进作用最大，达100ng／ml时对ACL细胞的促进作用最大。EGF在0．78ng／ml时即对MCL细胞有显著的促增殖作用，在1．56ng／ml时始对ACL细胞有显著的促增殖作用，其浓度达3．125ng／ml时对2种细胞的促进作用最大。aFGF和EGF在超过其最佳浓度后，随浓度升高促进作用均下降。结论：aFGF和EGF可以促进韧带成纤维细胞增殖。     

Effect of dehydroepiandrosterone sulfate on the mineral accretion of chick embryo frontal bones cultivatedin vitro

Chick embryo frontal bones at 12 and 13 days of development cultivatedin vitro exhibit different patterns of glucose utilization, periosteal cellular density and calcium and hydroxyproline content. When dehydroepiandrosterone sulfate is added to the medium at a concentration 1 mM, 12-day frontals engage primarily in osteoid tissue synthesis while 13-day frontals calcify at a significantly greater rate than controls. Measured with the ratio calcium/hydroxyproline, the calcification of 13-day frontals follows a linear function with the logarithm of the doses of dehydroepiandrosterone sulfate employed (0.5, 1.0 and 2.0 mM). The 13-day frontal bone cultivatedin vitro seems to be an adequate experimental model for the study of the effects of dehydroepiandrosterone sulfate on bone tissue because it reproduces the basic phenomenon (increased calcification) observed in man and animals treated with androgens.     

The healing potential of the periosteum molecular aspects

The presence of pluripotential mesenchymal cells in the under surface of the periosteum in combination with growth factors regularly produced or released after injury, provide this unique tissue with an important role in the healing of bone and cartilage. The periosteum contributes in the secondary callus formation with cells and growth factors and should always be preserved and protected when surgery is performed for the management of a fracture. The current evidence about the cellular interactions, the stimulants and the signalling pathways related to osteogenesis and chondrogenesis is described. An essential knowledge of the basics related to the contribution of the periosteum in the healing of fractures, osteotomies, during the process of distraction osteogenesis and in some degree in the repair of cartilagenous defects, provides the surgeons with a better insight to understand the upcoming "biological" interventions in the management of skeletal injuries.     

The effect of dehydroepiandrosterone sulfate and testosterone on the development of chick embryo frontal bones in vitro

Chick embryo frontal bones at 12 days of development, cultivated in vitro on plasma clots with dehydroepiandrosterone sulfate in a concentration 1mM, exhibit periosteal hyperplasia and increased synthesis of osteoid tissue. These phenomena are not observed when 11-day frontals are cultivated in similar conditions. Testosterone produces the same effects as dehydroepiandrosterone sulfate. Both steroids seem to act directly on bone as can be inferred from the experimental conditions employed.The alkaline phosphatase activity of chick embryo frontal bones at 12 days of development is significantly increased when the rudiments are cultivated in a medium containing dehydro-epiandrosterone or testosterone. In both cases a) enzyme kinetics experiments revealed that there is activation of the enzyme and b) the apparent maximum velocities obtained are hihgly correlated with the logarithm of the doses employed. When assayed simultaneously, both steroids were found equally active in promoting the increase in alkaliue phosphatase activity.

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Zusammenfassung Wenn Stirnknochen von 12 Tage alten Hühnerembryonen in vitro auf koaguliertem Plasma mit Zusatz von 1 mM Dehydroepiandrosteronsulfat gezüchtet werden, so zeigen sie eine Hyperplasie des Periostes und eine erhöhte Synthese des Osteoidgewebes. Diese Erscheinung trifft nicht zu, ween 11 tägige Stirnknochen in gleicher Weise gezüchtet werden. Mit Testosteron werden gleiche Effekte wie mit Dehydroepiandrosteronsulfat erzielt. Aus den gewählten Versuchsverhältnissen kann abgeleitet werden, daß beide Steroide direkt auf den Knochen zu wirken scheinen.Die Aktivität der alkalischen Phosphatase im Stirnknochen des 12 Tage alten Hühnerembryos ist signifikant erhöht, wenn die Knochenansätze in einem Dehydroepiandrosteron oder Testosteron enthaltenden Medium gezüchtet werden. In beiden Fällen ergeben enzymkinetische Untersuchungen einerseits eine Aktivierung des Enzyms, andererseits eine gute Korrelation der erhaltenen scheinbaren Maximalgeschwindigkeiten mit dem Logarithmus der verwendeten Dosen. Bei gleichzeitiger Prüfung bewirkten beide Steroide gleichzeitig eine ähnliche Aktivitätszunahme der alkalischen Phosphatase.

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Résumé Les os frontaux d'embryons de poulet, de 12 jours de développement, cultivés sur coagulum de plasma avec sulfate de déhydroépiandrostérone (DS) en concentration 1 mM, montrent hyperplasie du périoste et synthèse augmentée du matrice osseuse. Ces phénomenes ne son pas vus quand on emploie les os frontaux de 11 jours de développement. La testostérone produit les mêmes effets que le DS. Le deux steroïdes semblent agir directement sur l'os selon on peut le déduire des conditions expérimentales.L'activité de la phosphatase alcaline des frontaux d'embryons de poulet de 12 jours de développement est augmentée de manière significative quand les rudiments son cultivés dans un milieu qui contient DS ou testostérone. Dans ces deux cas: a) on peut révéler l'activation de l'enzyme par des expériences de cinétique enzymatique et b) les vélocités maximes apparantes ont une grande correlation avec le logarithme des doses employées. Quand les deux steroïdes son essayés en conditions semblables, les deux produisent la même augmentation de l'activité phosphatasique.

     

碱性成纤维细胞生长因子和血管生成与胃癌发展的关系

目的:探讨碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)和血管生成与胃癌发展的关系.方法:应用免疫组织化学方法检测56例人胃癌组织碱性成纤维细胞生长因子表达和微血管密度(microvasculardensity,MVD),分析bFGF和MVD及其与胃癌组织学分型、浸润深度、生长方式、淋巴结转移、远处转移和预后的关系.结果:bFGF阳性者MVD值显著高于bFGF阴性者(P<0.01),MVD值和bFGF表达与胃癌浸润深度(P<0.05)、淋巴结转移(P<0.01)和远处转移(P<0.05)密切相关;MVD≥43或bFGF表达阳性的胃癌患者5年生存率较低.结论:血管生成在胃癌发展中具有重要作用,bFGF不仅与胃癌的血管生成有关,而且与胃癌的生长和浸润转移也有关,MVD或bFGF可作为判断胃癌患者预后的指标.