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Skull
Kinds of Skull Terms modified by Skull Selected AbstractsAmeloblastic Carcinoma of the Mandible Metastatic to SkullTHE LARYNGOSCOPE, Issue S1 2009Christie L. Morgan MS No abstract is available for this article. [source] A Landmark Analysis-Based Approach to Age and Sex Classification of the Skull of the Mediterranean Monk Seal (Monachus monachus) (Hermann, 1779)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2009C. Brombin Summary This work aimed at applying geometric morphometric analysis techniques to the skull of the Mediterranean monk seal (Monachus monachus, Hermann, 1779). Inferential analyses were performed using a non-parameteric permutation framework based on a series of skulls of different age classes belonging to individuals of both sexes. Our goal was to establish whether a statistical approach based on osteometric measurements and surface analysis of photographs of the left lateral plane of the skull may lead to a different and scientifically sound method of age and sex classification in this critically endangered marine mammal. Our data indicate that non-parametric combination methodology enables the researcher to give local assessment using a combination with domains. Developing geometric morphometric techniques in a non-parametric permutation framework could be useful in solving high dimensional and small sample size problems as well as classification problems, including zoological classification of specimens within a specific population. The Mediterranean monk seal is believed to be the world's rarest pinniped and one of the most endangered mammals of the world, with fewer than 600 individuals currently surviving. The use of shape analysis would allow new insights into the biological characteristics of the monk seal by simply extracting potentially new information on age and size from museal specimens. [source] Conformation of the Equine Skull: A Morphometric StudyANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 4 2006K. E. Evans Summary There is a lack of an established method for quantifying equine skull morphology. This study proposes a method that is valid for use on both live and deceased horses. A total of nine head measurements (skull length, cranial length, nasal length, ratio of cranial:nasal length, cranial width, zygomatic width, mandibular depth, nasal profile area, cranial profile area) and six indices (skull index, cranial index, nasal index, mandibular index, nasal profile index, cranial profile index) were recorded from 30 horses from a variety of breeds whilst the soft tissues of the head were intact. A line was drawn level with the palpable notches caudal to the caudal lacrimal process of each orbit to estimate the suture line of the nasal and frontal bones and distinguish between the neurocranium and splanchnocranium. There were positive correlations between many of the head measurements. This method also illustrated significant differences in the skull morphology of three breeds (Arabians, thoroughbreds and standardbreds). [source] Comparative Anatomical Study on Fissura Nasolacrimalis and Nasomaxillaris in Skull of the Korean Native Goat (Capra hircus)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 3 2001S. J. Yi We found specific anatomical strucutre on the fissura nasolacrimalis and fissura nasomaxillaris of the skull of the Korean native goat. It has quite a wide opening on each side of the os nasale and could be classified into four types according to various patterns of articulations of the neighbouring bones. [source] Photocrosslinkable Chitosan Hydrogel Can Prevent Bone Formation in Both Rat Skull and Fibula Bone DefectsARTIFICIAL ORGANS, Issue 1 2009Yoshifumi Tsuda Abstract UV light irradiation to a photocrosslinkable chitosan (Az-CH-LA) resulted in an insoluble and flexible hydrogel within 30 s. The purpose of this study was to evaluate the ability of the photocrosslinkable chitosan to inhibit bone formation in the bone defects. A 5-mm-diameter defect was made in the rat calvarium, and then photocrosslinkable chitosan was implanted and irradiated with UV for 30 s. Furthermore, a 2-mm defect was made in the fibula of a rat hind leg, and then photocrosslinkable chitosan was implanted and irradiated with UV. Bone formations in the rat skull and fibula defects with photocrosslinkable chitosan hydrogel were significantly prevented for 8 weeks. Thus, the chitosan hydrogel has an inhibitory effect on bone formation. [source] Enantiornithine Bird with Diapsidian Skull and Its Dental Development in the Early Cretaceous in Liaoning, ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2004GONG Enpu Abstract A large number of enantiornithine birds are discovered from the Early Cretaceous Jiufutang Formation in western Liaoning, China. They are all small-sized birds with a few small teeth. The enantiornithine bird from the Jiufutang Formation in the Shangheshou area, Chaoyang, Liaoning Province reported in this paper is the largest individual known in all enantiornithine birds of the Early Cretaceous. However, its teeth possess a feature of pseudoheterodont. Some different development stages of the new teeth substitute the earlier stages and the stages of development are preserved in this specimen. This development pattern is similar to that of Archaeopteryx and alligator but not dinosaur. A well-developed postorbital was also preserved in the skull, which was a diapsidian skull like that of Confuciusornis. Additionally, the distinctive preservation of its prefrontal distinguishes it from other enantiornithine birds of the Early Cretaceous. [source] The Craniofacial Reconstruction from the Local Structural Diversity of SkullsCOMPUTER GRAPHICS FORUM, Issue 7 2008Yuru Pei Abstract The craniofacial reconstruction is employed as an initialization of the identification from skulls in forensics. In this paper, we present a two-level craniofacial reconstruction framework based on the local structural diversity of the skulls. On the low level, the holistic reconstruction is formulated as the superimposition of the selected tissue map on the novel skull. The crux is the accurate map registration, which is implemented as a warping guided by the 2D feature curve patterns. The curve pattern extraction under an energy minimization framework is proposed for the automatic feature labeling on the skull depth map. The feature configuration on the warped tissue map is expected to resemble that on the novel skull. In order to make the reconstructed faces personalized, on the high level, the local facial features are estimated from the skull measurements via a RBF model. The RBF model is learnt from a dataset of the skull and the face feature pairs extracted from the head volume data. The experiments demonstrate the facial outlooks can be reconstructed feasibly and efficiently. [source] An examination of skulls from two British sites for possible evidence of scurvyINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 4 2003M. Melikian Abstract Skulls and mandibles from the Romano-British site of Poundbury, Dorset and a medieval site at Abingdon in Oxfordshire were examined for porosity which has been considered to be indicative of the presence of scurvy. In addition, a number of skulls from various locations in Peru were examined. Virtually all the skulls had porosity at at least one site and in all cases the palate was most frequently affected. The rank order of affected sites showed some differences between the three samples but the most striking change was the frequency with which the cranial vault and maxilla were affected in the Peruvian skulls compared with the British. The differences were not statistically significant, however. None of the appearances was consistent with those of known cases of infantile scurvy and we doubt whether scurvy can be diagnosed on the basis of porosity in the skull and mandible unless it conforms to recognized clinical patterns. Copyright © 2003 John Wiley & Sons, Ltd. [source] DTI in Context: Illustrating Brain Fiber Tracts In SituCOMPUTER GRAPHICS FORUM, Issue 3 2010Pjotr Svetachov Abstract We present an interactive illustrative visualization method inspired by traditional pen-and-ink illustration styles. Specifically, we explore how to provide context around DTI fiber tracts in the form of surfaces of the brain, the skull, or other objects such as tumors. These contextual surfaces are derived from either segmentation data or generated using interactive iso-surface extraction and are rendered with a flexible, slice-based hatching technique, controlled with ambient occlusion. This technique allows us to produce a consistent and frame-coherent appearance with precise control over the lines. In addition, we provide context through cutting planes onto which we render gray matter with stippling. Together, our methods not only facilitate the interactive exploration and illustration of brain fibers within their anatomical context but also allow us to produce high-quality images for print reproduction. We provide evidence for the success of our approach with an informal evaluation with domain experts. [source] The Craniofacial Reconstruction from the Local Structural Diversity of SkullsCOMPUTER GRAPHICS FORUM, Issue 7 2008Yuru Pei Abstract The craniofacial reconstruction is employed as an initialization of the identification from skulls in forensics. In this paper, we present a two-level craniofacial reconstruction framework based on the local structural diversity of the skulls. On the low level, the holistic reconstruction is formulated as the superimposition of the selected tissue map on the novel skull. The crux is the accurate map registration, which is implemented as a warping guided by the 2D feature curve patterns. The curve pattern extraction under an energy minimization framework is proposed for the automatic feature labeling on the skull depth map. The feature configuration on the warped tissue map is expected to resemble that on the novel skull. In order to make the reconstructed faces personalized, on the high level, the local facial features are estimated from the skull measurements via a RBF model. The RBF model is learnt from a dataset of the skull and the face feature pairs extracted from the head volume data. The experiments demonstrate the facial outlooks can be reconstructed feasibly and efficiently. [source] Radiological protection for diagnostic examination of pregnant womenCONGENITAL ANOMALIES, Issue 1 2002Tomoko Kusama ABSTRACT, Application of diagnostic X-ray examination to pregnant women is complicated since risks to both mother and embryo/fetus must be considered. Embryos and fetuses are more sensitive to radiation than adults or children. The threshold doses for fetal death, malformations and mental retardation which are deterministic effects, are reported to be 100,200 mGy or higher. The relative risk for childhood cancer due to radiation at an absorbed dose of 10 mGy during embryonic/fetal development has been estimated at 1.4. However, the absorbed dose of the embryo/fetus during X-ray diagnostic examination in which the X-ray beam does not irradiate the embryo/fetus directly such as maternal skull and chest X-ray is extremely low, less than 0.01 mGy. Thus these diagnostic procedures are not a problem from the perspective of radiological protection of the embryo/fetus. However, for pelvic CT scan and barium enema in which the uterus is directly within the X-ray beam, the absorbed doses to the embryo/fetus are about 20,80 mGy and 10,20 mGy, respectively. Therefore, medical staff must pay careful attention to the embryo/fetus in application of these examinations. Pregnant women who were not aware of pregnancy at the time of their diagnostic exposure have great anxiety about radiation from such X-ray examinations. However, fetal doses below 100 mGy should not be considered a reason for terminating a pregnancy. [source] Effectiveness of limited cone-beam computed tomography in the detection of horizontal root fractureDENTAL TRAUMATOLOGY, Issue 3 2009vanç Kamburo Root fractures were created in the horizontal plane in 18 teeth by a mechanical force and fragments were relocated. Another 18 intact teeth with no horizontal root fracture served as a control group. Thirty-six teeth were placed in the respective empty maxillary anterior sockets of a human dry skull in groups three by three. Intraoral radiographs were obtained in three different vertical views by utilizing Eastman Kodak E-speed film, CCD sensor, RVG 5.0 Trophy and a PSP sensor Digora, Optime. Cone beam CT images were taken with a unit (3D Accuitomo; J Morita MFG. Corp, Kyoto, Japan). Three dental radiologists separately examined the intraoral film, PSP, CCD and cone beam CT images for the presence of horizontal root fracture. Specificity and sensitivity for each radiographic technique were calculated. Kappa statistics was used for assessing the agreement between observers. Chi-square statistics was used to determine whether there were differences between the systems. Results were considered significant at P < 0.05. Cone beam CT images revealed significantly higher sensitivities (P < 0.05) than the intraoral systems between which no significant differences were found. Specificities did not show any statistically significant differences between any of the four systems. The kappa values for inter-observer agreement between observers (four pairs) ranged between 0.82,0.90 for the 3DX evaluations and between 0.63,0.71 for the different types of intraoral images. Limited cone beam CT, outperformed the two-dimensional intraoral, conventional as well as digital, radiographic methods in detecting simulated horizontal root fracture. [source] An experimentally calibrated finite element study of maxillary traumaDENTAL TRAUMATOLOGY, Issue 5 2007Michael J Casas Abstract,,, A baseball injury to an instrumented human cadaver maxillae was simulated with a regulation (142 g) baseball traveling at 14 m s,1. Measurements of strain were obtained with three-axis strain gauge rosettes located at the medial palate and both canine fossae. A three-dimensional finite element (FE) model of a dentate human maxilla was constructed from computed tomography scans of the skull of an adolescent. This three-dimensional mathematical model of the maxilla was deemed geometrically accurate by convergence testing when the model's degrees of freedom approximated 74 000. The simulated load case involved a transient dynamic impact to the medial maxilla with boundary conditions imposed at skeletal buttresses of the model. The model was calibrated through direct comparison with the displacements and principal strains gathered from experimental and epidemiological data. The comparison of experimental and calculated principal strains as a result of the simulated impacts revealed a 1.7,11.4% difference. [source] Identification of Tgf,1i4 as a downstream target of Foxc1DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 5 2006Paula Sommer Craniofacial development is severely affected by null mutations in Foxc1, indicating a multifunctional role for Foxc1 in ocular, maxilla and mandible, skull and facial gland development. To delineate signaling pathways in which Foxc1 is involved we compared the transcriptomes of whole heads of Foxc1+/+ and Foxc1,/, embryos using a candidate cDNA array comprising genes expressed in the head mesenchyme and ocular region, and a 7K oligo array. Absence of Foxc1 led to downregulation of Stat1 and Galnt4, and upregulation of Tgf,1i4 at embryonic day 13.5 in the developing head mesenchyme. Comparative analyses revealed differences in the expression pattern of Tgf,1i4 in the head mesenchyme of Foxc1,/, and Foxc1+/+ embryos. In the ocular regions of Foxc1,/, embryos, Tgf,1i4 was expressed in higher levels in the conjunctival epithelium and in the condensing mesenchyme on the nasal aspect of the developing eye while in wild-type embryos more intense expression was seen in the mesenchyme on the temporal aspect of the eye. Such data indicate that Foxc1 regulation of Tgf,1i4 is complex and may be cell-type dependent. Analysis of the regulation of Tgf,1i4 by Foxc1 in a more homogenous cell population, mesenchymal cells isolated from the periocular region revealed that, in these cells, Foxc1 negatively regulated Tgf,1i4 expression, presumably via secreted factors such as TGF-,1. Since Foxc1 expression is essential for normal craniofacial development, it is possible that its downstream targets play a role in the development of the phenotypes associated with null mutations in Foxc1. [source] Papillary thyroid carcinoma with metastasis to the frontal skullDIAGNOSTIC CYTOPATHOLOGY, Issue 7 2009Dian Feng M.D., Ph.D. Abstract Papillary thyroid carcinoma with metastasis to the frontal skull is extremely rare. We report a case of unsuspected papillary thyroid carcinoma with frontal skull metastasis. The patient was a 62-year-old African American woman with presentation of a 4-cm firm, painless, immobile, ill-defined mass at the right forehead. Ultrasound and computer tonography detected a hypervascular and osteolytic tumor involving the skull and overlying skin. Fine-needle aspiration was performed followed by surgical biopsy. Cytologic examination revealed the presence of hypercellular and bloody material. The neoplasm showed glandular features and was composed of clusters of round to oval cells with pinkish squamoid cytoplasm, oval nuclei and inconspicuous nucleoli on smears and sections of cell block. With immunocytochemical stain, the neoplastic cells were positive for pancytokeratin and vimentin and focally positive for EMA, while they were negative for S100, HMB45, Melan-A, CD34, GFAP, CD10, LCA, RCC and CD138. The diagnosis was a metastatic carcinoma. Clinical follow up with surgical biopsy was recommended. Surgical biopsy demonstrated histological and cytological features of papillary thyroid carcinoma including prominent papillae, nuclear overlapping, grooves, and intranuclear pseudoinclusions. Thus, a diagnosis of metastatic papillary thyroid carcinoma was rendered. Though skull metastasis of thyroid carcinoma is rare, it should be considered in the differential diagnosis when a skull mass lesion is encountered. Diagn. Cytopathol. 2009. © 2009 Wiley-Liss, Inc. [source] The skull of Vanzosaura rubricauda (Squamata: Gymnophthalmidae)ACTA ZOOLOGICA, Issue 4 2009Cecilia Guerra Abstract A detailed description of the cranial osteology and chondrocranium of Vanzosaura rubricauda is made based both on articulated and partially disarticulated material of dry skeletons and cleared and stained specimens, and is compared with other previously studied gymnophthalmids. Some features of Vanzosaura are interesting, such as the reduction of the supratemporal fenestrae, that may reflect a process of miniaturization, and the fusion of the occipital bones in a single oto-occipital complex with no evident sutures. Based on the anatomical evidence, the skull of Vanzosaura is interpreted as amphikinetic. [source] Morphological variation of the five vole species of the genus Microtus (Mammalia, Rodentia, Arvicolinae) occurring in GreeceACTA ZOOLOGICA, Issue 3 2009Stella E. Fraguedakis-Tsolis Abstract Morphometric data for the five vole species of the genus Microtus living in Greece are old, sparse, poor and insufficiently analysed. This work aims to give the first comprehensive morphometric analysis of body and skull inter- and intraspecific variation for M. (M.) guentheri, M. (M.) rossiaemeridionalis, M. (Terricola) subterraneus, M. (T.) felteni and M. (T.) thomasi, applying multivariate statistics to 28 linear morphometric variables. It was based on ample material (202 adult individuals) using samples from localities that adequately cover the entire distributional range of each species in Greece. The five species and the two subgenera (Microtus and Terricola) were morphometrically clearly distinguished and discriminating variables were revealed. However, morphometrics did not provide robust criteria to infer phylogenetic relations among species. Furthermore, three species, M. (M.) guentheri, M. (M.) rossiaemeridionalis and M. (T.) thomasi, exhibited considerable intraspecific size or shape variation, which was mostly random and not associated with geographical proximity. Comparisons with data in the literature, mainly concerning populations of these species from adjacent areas, indicate that the Greek M. (M.) guentheri, M. (M.) rossiaemeridionalis and M. (T.) thomasi tend to be smaller than their conspecifics, while M. (T.) subterraneus and M. (T.) felteni are about equal in size to their Balkan relatives. [source] An enigmatic gnathostome vertebrate skull from the Middle Devonian of BoliviaACTA ZOOLOGICA, Issue 2009Alan Pradel Abstract A new taxon, Ramirosuarezia boliviana n. gen., n. sp. is erected for a single, articulated jawed fish (gnathostome) skull from the Middle Devonian (Eifelian) Icla Formation of Bolivia. The specimen displays an elasmobranch-like braincase, but lacks unambiguous elasmobranch and even chondrichthyan characters, although its peculiar tooth-bearing ,labial' elements evoke certain stem-holocephalans. Its endoskeletal elements seem lined with either perichondral bone or non-prismatic calcified cartilage, but show no evidence of endochondral bone. Although devoid of large dermal bones and scales, R. boliviana shares with certain ,ostracoderms', placoderms and holocephalans the lack of an otico-occipital fissure, but lacks a hypophysial fenestra. Certain features (elongated braincase, ,labial elements', sharp denticles and teeth) are also suggestive of the equally enigmatic coeval stensioellids, once regarded as either primitive placoderms or stem holocephalans. The jaws are armed with platelets that bear blunt to pointed and sharp teeth, in which synchrotron radiation microtomography yields evidence of a large pulp cavity, a possibly osteichthyan-like character. No character clearly supports affinities of R. boliviana to any of the currently known major gnathostome groups. Tenuous hints suggest a relationship to the enigmatic fossil Zamponiopteron, from the Eifelian of Bolivia, known by peculiar calcified ,fin plates' and isolated shoulder girdles. [source] Heddleichthys, a new tristichopterid genus from the Dura Den Formation, Midland Valley, Scotland (Famennian, Late Devonian)ACTA ZOOLOGICA, Issue 2009Daniel Snitting Abstract A new tristichopterid genus, Heddleichthys, from the Famennian of Scotland is described based on material previously assigned to a number of different genera, including Glyptopomus, Gyroptychius and Eusthenopteron. The validity of the new genus is established by a discussion of the reasons for the invalidity of the previous assignments. Heddleichthys is characterized by a combination of derived and primitive tristichopterid features. Derived features include the presence of symphyseal dentary fangs and premaxillary pseudofangs, a diamond-shaped symmetric caudal fin, a low posterodorsal expansion of the maxilla, and a posteriorly positioned kite-shaped pineal series. Primitive features include a postorbital and jugal contribution to the orbital margin and a parasphenoid with a ventral keel. External dermal bones are rather poorly preserved in the referred material, with few easily discernible sutures. The holotype specimen, a three-dimensionally preserved skull, was scanned by computed tomography to reveal well-preserved internal dermal bones, including entopterygoids, vomers and parasphenoid. There is no preserved endoskeletal material. As the first representative of derived tristichopterids described from Britain, Heddleichthys lends support to the idea that faunal dispersion between Gondwana and Laurussia in the Late Devonian was widespread. Derived tristichopterids have been described from all continents except South America. In contrast, the basal tristichopterids Eusthenopteron and Tristichopterus are still only described from Laurussia. [source] A new specimen of Baphetes from Ný,any, Czech Republic and the intrinsic relationships of the BaphetidaeACTA ZOOLOGICA, Issue 2009Angela C. Milner Abstract ,Loxomma'bohemicum from the Upper Carboniferous assemblage from Ný,any, Czech Republic, is a nomen dubium restricted to the type and only specimen. The new binomen Baphetes orientalis is created for a skull referred to Baphetes bohemicus by later authors. A previously undescribed baphetid specimen from Ný,any is referred to B. orientalis despite differences in skull proportions. It comprises a skull in dorsal aspect, mandibles and some associated postcranial elements. The skull possesses sclerotic ring elements within the orbital region of the dorsal fenestration of the skull, confirming the eye location. The elongate gastralia are arranged perpendicular to the interclavicle edge in contrast to the condition in temnospondyls and colosteids. Cladistic analysis of 24 characters of 11 baphetoids was carried out using Acanthostega and Crassigyrinus as outgroups. Eucritta was the most primitive baphetoid, with Spathicephalus being the sister-taxon to the remaining taxa, justifying a monotypic Spathicephalidae as a sister-taxon to the Baphetidae. The Baphetidae are divided into a subfamily Baphetinae nom.nov. containing two Baphetes species; and a subfamily Loxommatinae with Loxomma as a paraphyletic grade leading to a Megalocephalus +Kyrinion clade. The Linton taxon ,Baphetes' lintonensis is transferred to the genus Loxomma to give the new combination Loxomma lintonensis. [source] Comparative growth in the postnatal skull of the extant North American turtle Pseudemys texana (Testudinoidea: Emydidae)ACTA ZOOLOGICA, Issue 2 2008Gabe S. Bever Abstract Bever, G.S. 2007. Comparative growth in the postnatal skull of the extant North American turtle Pseudemys texana (Testudinoidea: Emydidae). ,Acta Zoologica (Stockholm) 88: 000,000 Postnatal growth is one of the many aspects of developmental morphology that remains distinctly understudied in reptiles. Variation and ontogenetic scaling within the skull of the extant emydid turtle, Pseudemys texana is described based on 25 continuous characters. Results indicate that skull shape in this species changes little during postnatal growth relative to the only cryptodire taxa for which comparable datasets are available (Apalone ferox and Sternotherus odoratus). This relative lack of change results in the paedomorphic retention of a largely juvenile appearance in the adult form of P. texana. The skulls of males and females, despite the presence of distinct sexual dimorphism in size, grow with similar scaling patterns, and the few observed differences appear to reflect alteration of the male growth trajectory. Comparisons with A. ferox and S. odoratus reveal a number of similarities and differences that are here interpreted within a phylogenetic context. These preliminary hypotheses constitute predictive statements that phylogenetically bracket the majority of extant cryptodire species and provide baseline comparative data that are necessary for the future recognition of apomorphic transformations. Plasticity of ontogenetic scaling as a response to the homeostatic needs and behaviour of individuals commonly is evoked as a limitation of ontogenetic scaling as a means to inform phylogenetic studies. These evocations are largely unfounded considering that variability itself can evolve and thus be phylogenetically informative. [source] Diet-induced phenotypic plasticity in the skull morphology of hatchery-reared Florida largemouth bass, Micropterus salmoides floridanusECOLOGY OF FRESHWATER FISH, Issue 4 2005A. P. Wintzer Abstract , Hatchery-reared Florida largemouth bass, Micropterus salmoides floridanus, feed on inert pellet food while their wild counterparts capture elusive prey. Differences in levels of prey elusivity often mandate the use of alternate methods of prey capture. This study examines whether elusivity-based variation in prey capture translates to a phenotypic change during skull development, and if this change results in a functional difference in the feeding mechanism. The developmental pattern of the skull was conserved between hatchery and wild bass until 80,99 mm TL. At this point, wild bass quickly developed morphological changes of the jaw apparatus including a more fusiform head and elongated jaw structures. Natural development in hatchery bass, however, was retarded at this size. Post-release, the skulls of hatchery fish converged towards those of wild bass by 135 mm TL. Despite variation in skull development, no theoretical advantage in food capture was found between these two groups. Resumen 1. Los individuos de Micropterus salmoides floridanus criados en cautividad se alimentan de cápsulas inertes de comida mientras que sus congéneres salvajes capturan presas elusivas. A menudo diferencias en los niveles de elusividad de las presas permiten la utilización de métodos alternativos para capturar presas. Este estudio examina si la variación basada en la elusividad de la captura de presas se traduce en un cambio fenotípico durante el desarrollo del cráneo y si este cambio resulta en una diferencia funcional en el mecanismo de alimentación. 2. El patrón de desarrollo del cráneo se mantuvo entre individuos criados en cautividad y en individuos salvajes hasta los 80,99 mm longitud total. En este punto, los individuos salvajes desarrollaron rápidamente cambios en el aparato mandibular incluyendo una cabeza más fusiforme y estructuras mandibulares mas alargadas. Sin embargo, en individuos de cautiverio, el desarrollo natural se retrasó en este tamaño. 3. Tras una suelta, los cráneos de individuos procedentes de cautiverio convergieron hacia los individuos salvajes en los 135 mm longitud total. A pesar de la variación en el desarrollo del cráneo, no encontramos ninguna ventaja teórica en la captura de alimento entre estos dos grupos. [source] Application of the equivalent multipole moment method with polar translations to forward calculation of neuromagnetic fieldsELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 4 2008Shoji Hamada Abstract This paper describes an application of the equivalent multipole moment method (EMMM) with polar translations to calculation of magnetic fields induced by a current dipole placed in a human head model. Although the EMMM is a conventional Laplacian field solver based on spherical harmonic functions, the polar translations enable it to treat eccentric and exclusive spheres in arbitrary arrangements. The head model is composed of seven spheres corresponding to skin, two eyeballs, skull, cerebral spinal fluid, gray matter, and white matter. The validity of the calculated magnetic fields and the magnetic flux linkages with a loop coil located near the model is successfully confirmed by the reciprocity theorem derived by Eaton. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(4): 34,44, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10079 [source] Development of Amygdaloid Kindling in Histidine Decarboxylase,deficient and Histamine H1 Receptor,deficient MiceEPILEPSIA, Issue 4 2004Tadashi Hirai Summary: Purpose: This study attempted to clarify the role of histamine or histamine H1 receptors in the development of amygdaloid kindling by using histidine decarboxylase (HDC)-deficient and histamine H1 receptor (H1R)-deficient mice. Methods: Under pentobarbital anesthesia, mice were fixed to a stereotaxic apparatus, and bipolar electrodes were implanted into the right amygdala. Electrodes were connected to a miniature receptacle, which was embedded in the skull with dental cement. A bipolar electroencephalogram was recorded; bipolar stimulation of the amygdala was applied every day with a constant-current stimulator and continued until a generalized convulsion was obtained. Results: The development of amygdaloid kindling in HDC-deficient and H1R-deficient mice was significantly accelerated compared with that in their respective wild-type mice. In addition, the afterdischarge (AD) duration and generalized seizure duration in HDC-deficient and H1R-deficient mice were prolonged. Intraperitoneal injection of histidine resulted in an inhibition of amygdaloid kindled seizures in wild-type mice at doses that caused an increase in the histamine contents of the brain. However, no significant effect was observed with histidine in H1R-deficient mice at the same dose. Conclusions: These findings suggest that histaminergic mechanisms through H1 receptors play a crucial role not only in amygdaloid kindled seizures but also in the development of amygdaloid kindling. [source] Dipole Tracing Examination for the Electric Source of Photoparoxysmal Response Provoked by Half-Field StimulationEPILEPSIA, Issue 2000Kazuhiko Kobayashi Purpose: Dipole tracing (DT) is a computer-aidcd noninvasive method used to estimate the location of epileptic discharges from the scalp EEG. In DT equivalent current dipoles (ECDs), which rcflcct the electric source in the brain, are rcsponsible for the potential distribution on the scalp EEC. Thercfore, the DT method is useful to estimatc the focal paroxysmal discharges. In this study we examined the location of the clectric source of photoparoxysmal response (PPR) using scalpskull-brain dipolc tracing (SSB-DT) after hal[-field stimulation, which produced focal PPR on the scalp EEG. Methods: We studied 4 cases of photoscnsitive epilepsy. Wc performed 20 Hz red flicker and flickcring dot pattern half-ficld stimulation to provoke PPR. In this method, the loci of gcnerators corresponding to the paroxysmal discharges were estimated as ECDs by I - and 2-dipole analyses. Each location of the ECDs was estimated by iterative calculation. Algorithms minimizing the squarcd difference betwccn the electrical potentials recorded from the scalp EEG and those calculated theoretically from the voluntary dipoles were uscd. In the SSB model, the scalp shell was reconstructed from the helmet mcasurements, and the shapc of the skull and brain was 3-dimcnsionally reconstructed from CT images. A dipolarity larger than 98% w the accuracy of the estimation. We recorded thcir 2 I channel monopolar scalp EEG. Each spike was sampled analyzed at 10 points around the peaks of at least 10 spikes in each patient using the SSB-DT method. The ECDs were then supcrimposed on thc MRI of each palient to idcntify the more cxact anatomical region. Results: This study showed the location of cach focus and a dipolarity of greater than 98% in all cases, although the results from the 2-dipole method showed scattered location. We considered that the analyzed signals were generated from single source. PPR was elicitcd cross-lateral to the field stimulated. By red flicker half-field stimulation, EEG revealed eithcr focal spikes and waves in the contralatcral occipital, temporo-occipitel region, or diffuse spikes and wave complex bursts, sccn dominantly at the contralateral hcmisphere. The supcrimposed ESDs on MRI were located at the occipital or inferior temporal lobe. PPR, provoked by flickering dot pattern half-field stimulation, werc focal spikes and waves, mainly in the occipital, parieto-occipital region, or diffuse spikes and wave complcx bursts, seen dominantly at thc contralateral hcmiaphere. The ECDs of their PPRs were located in the occipital, inferior temporal, or inferior pirietal lobules on MRI. Conclusion: Our findings suggest that the inferior temporal and inferior parictal lobules which are important for the processing sequence of the visual system in addition to the occipital lobc, might he responsible for thc mechanism of PPR by half-ficld stimulation, espccially for electric source expansion. [source] A comparison between two-dimensional and three-dimensional cephalometry on frontal radiographs and on cone beam computed tomography scans of human skullsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2009Olivier J. C. Van Vlijmen The aim of this study was to evaluate whether measurements performed on conventional frontal radiographs are comparable to measurements performed on three-dimensional (3D) models of human skulls derived from cone beam computed tomography (CBCT) scans and if the latter can be used in longitudinal studies. Cone beam computed tomography scans and conventional frontal cephalometric radiographs were made of 40 dry human skulls. From the CBCT scan a 3D model was constructed. Standard cephalometric software was used to identify landmarks and to calculate ratios and angles. The same operator identified 10 landmarks on both types of cephalometric radiographs, and on all images, five times with a time interval of 1 wk. Intra-observer reliability was acceptable for all measurements. There was a statistically significant and clinically relevant difference between measurements performed on conventional frontal radiographs and on 3D CBCT-derived models of the same skull. There was a clinically relevant difference between angular measurements performed on conventional frontal cephalometric radiographs, compared with measurements performed on 3D models constructed from CBCT scans. We therefore recommend that 3D models should not be used for longitudinal research in cases where there are only two-dimensional (2D) records from the past. [source] SHAPE ANALYSIS OF SYMMETRIC STRUCTURES: QUANTIFYING VARIATION AMONG INDIVIDUALS AND ASYMMETRYEVOLUTION, Issue 10 2002Christian Peter Klingenberg Abstract., Morphometric studies often consider parts with internal left-right symmetry, for instance, the vertebrate skull. This type of symmetry is called object symmetry and is distinguished from matching symmetry, in which two separate structures exist as mirror images of each other, one on each body side. We explain a method for partitioning the total shape variation of landmark configurations with object symmetry into components of symmetric variation among individuals and asymmetry. This method is based on the Procrustes superimposition of the original and a reflected copy of each landmark configuration and is compatible with the two-factor ANOVA model customary in studies of fluctuating asymmetry. We show a fully multivariate framework for testing the effects in the two-factor model with MANOVA statistics, which also applies to shapes with matching symmetry. We apply the new methods in a small case study of pharyngeal jaws of the Neotropical cichlid fish Amphilophus citrinellus. The analysis revealed that the symmetric component of variation in the pharyngeal jaws is dominated by the contrast between two alternative trophic morphs in this species and that there is subtle but statistically significant directional asymmetry. Finally, we provide some general recommendations for morphometric studies of symmetric shapes. [source] Conditional alleles of Msx1 and Msx2,GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 8 2007Hualin Fu Abstract The msh-related homeobox genes, Msx1 and Msx2, have a variety functions during murine organogenesis, Msx1 in the development of the palate and teeth, Msx2 in the skull, teeth, and skin. Msx1 mutants die perinatally. Compound Msx1-2 mutants do not survive past late gestation. The multiplicity of functions of Msx1 and 2, as well as the lethality of Msx1 and Msx1-2 mutants limits the utility of the conventional knockouts. We therefore produced conditional alleles of Msx1 and Msx2. We constructed targeting vectors with LoxP sites flanking the homeodomain-encoding second exons and Frt sites flanking a neo gene. These vectors were used to produce targeted ES cells and mice with floxed alleles. The functionality of the LoxP sites in the floxed alleles was established by crosses with K14-Cre mice (epidermis-specific), and with an Msx2 -Cre line that produces a germline deletion. Analysis of progeny by PCR revealed correct Cre-mediated recombination, as well as expected phenotypes. genesis 45:477,481, 2007. Published 2007 Wiley-Liss, Inc. [source] Hyperostosis cranii in the elderly with various clinical symptomsGERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 1 2004Makoto Sohmiya We report three elderly patients with hyperostosis cranii. Patient 1 had two episodes of unconsciousness; Patient 2, headache; and Patient 3, dementia. On the basis of Moore's classification using skull films, Patients 1 and 2 showed hyperostosis frontoparietalis and Patient 3 had hyperostosis frontalis interna. Electroencephalography showed transient generalized spike and slow wave complexes over the frontal lobes in Patient 1. Magnetic resonance images showed frontal lobes compressed by the thickness of the frontal bones in all patients and the thickness of the parietal bones in Patients 1 and 2. Since the findings in the present cases and those in the literature suggest that hyperostosis cranii could show unexpected neuropsychiatric symptoms, hyperostosis cranii should be checked in elderly patients whose presenting symptoms include epilepsy, dementia, psychiatric disease, headache and so on. Magnetic resonance images should be helpful in examining the relationship between clinical symptoms and the deformation of the brain by the skull. [source] Management of complicated head and neck wounds with vacuum-assisted closure systemHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 11 2006Brian T. Andrews MD Abstract Background The vacuum-assisted closure system (V.A.C.), or negative pressure dressings, has been successfully used to manage complex wounds of the torso and extremities, but its role in the head and neck region has not been frequently described. Methods A retrospective study was performed. The V.A.C. system (Kinetic Concepts Inc., San Antonio, TX) was used at the University of Iowa Hospitals and Clinics for management of complicated head and neck wounds. Results The V.A.C. system was utilized at 13 sites for 12 patients. Nine subjects had exposed calvarium (4 had failed pedicled reconstructive flaps, 3 had ablative or Moh's defects, and 2 had traumatic scalping injuries) necessitating bony coverage. Three subjects had the V.A.C. system used as a bolster dressing placed over split-thickness skin grafts (STSGs) used to reconstruct large defects of the face and skull, and 1 patient had a large soft tissue neck defect after radical surgical resection for necrotizing fascitis. One subject used the V.A.C. system for the management of 2 distinct wounds. All patients had successful healing of their wounds with the V.A.C. system without complication. All STSGs had 100% viability after 5 to 7 days of the V.A.C. system use as a bolster dressing. Conclusion This study demonstrates the V.A.C. system is a valuable tool in the management of complicated head and neck wounds. © 2006 Wiley Periodicals, Inc. Head Neck, 2006 [source] | |||||||||||||||||||||||||||||||||||||||||||