Pneumatic processes in the temporal bone of chimpanzee (Pan troglodytes) and gorilla (Gorilla gorilla)

The ontogeny of human temporal bone pneumatization has been well studied from both comparative and clinical perspectives. While a difference in the extent of air cell distribution has been noted in our closest living relatives, chimpanzees and gorillas, the processes responsible have been relatively unexplored. To examine these processes, a large, age‐graded series of hominoid skulls was radiographed and the progress of pneumatization recorded. Additionally, a subsample of 30 chimpanzees and 12 gorillas was subjected to high‐resolution CT scanning. Neonatal specimens show a well‐developed mastoid antrum, as well as a capacious hypotympanum extending into the petrous apex. In African apes, as in humans, the mastoid antrum serves as the focus for air cell expansion into the mastoid and immediately adjacent areas. In chimpanzees and gorillas, however, a pronounced lateral structure, described as the squamous antrum, serves as the focus of pneumatization for anterior structures such as the squamous and zygomatic. The diminution of this structure in Homo sapiens explains the difference in air cell distribution in these regions. J. Morphol. 241:127–137, 1999. © 1999 Wiley‐Liss, Inc.     

Development of early melanocytic lesions in transgenic mice predisposed to melanoma

We have previously described a line of transgenic mice (TG3) that spontaneously develops heritable malignant melanoma. Histological analysis of these animals during the first postnatal month is described here. In the TG3 line, the number of melanocytes is increased at all anatomical sites to which neural-crest-derived melanocytes normally migrate. Clonal expansion and morphological changes of these melanocytes can be detected as early as postnatal day (PND) 15. By PND 30, cells morphologically indistinguishable from the tumor cells of adult transgenic mice were detected in the ear, eye lid and perianal region. These cells are believed to be the precursors of the primary tumors in adult mice. The stepwise development of melanoma in the TG3 line is similar to the stepwise development of melanoma in humans.     

Measurements of the tympanic cavity

The angle between the annulus fibrocartilaginous and the superior crest of the petrous bone was measured with 14 (10 to 19) degrees. The height of the annulus was in our material 10.04 mm, the width 9.45 mm. Measured were also the length of the plicae malleares and the height of the recessus membrane tympani anterior, posterior et superior with (2.5, 3.0 and 1.5 mm). In about 74%, the chorda tympani was imbedded in different zones of the plicae malleares. Its entrance and exit areas, the length of its intratympanal course and its width were measured. Included are also values of the ligaments of the otic ossicles, measurements of the ostium tympanicum tubae auditivae, of the epitympanic recess, the aditus ad antrum, and the antrum mastoideum. The eminentia pyramidalis, the sinus posterior and the sinus tympani, ponticuli and subicula, the fossula fenestrae cochleae and the fenestra cochleae, the fenestra vestibuli and prominences of the facial canal in the lateral semicircular canal have been researched and measured. Also the tympanic nerve and its course on the promontorium have been estimated.     

Ontogeny and cranial morphology of the tympanic region of the Tupaiidae, with special reference to Ptilocercus

The structure of the tympanic region of the skull of Ptilocercus lowii was studied in an embryo of 30 mm crown-rump length and in 5 osteocrania. As in Tupaia, the anterior wall of the bulla of Ptilocercus is not completed by a tympanic process of the alisphenoid, contrary to earlier reports. Ptilocercus resembles Tupaia in the following derived characters. The ventral wall of the tympanic cavity is formed by a rostral entotympanic and by a caudal tympanic process of the petrosal. The entotympanic develops in primary connection with the tubal cartilage. The tympanic aperture of the auditory tube is bordered by the entotympanic. The ring-shaped tympanicum is covered by the entotympanicum and is aphaneric. The musculus tensor tympani is lacking. Among mammals, these characters can be regarded as synapomorphic for the Tupaiidae, that is, to have been present in the common ancestor of the two subfamilies. From the evidence of the tympanic region, the Tupaiidae, therefore, form a monophyletic group. Besides these synapomorphies, there are remarkable differences between Ptilocercus and Tupaia in the structure of the bulla. In Ptilocercus the bulla is smaller and less pneumatized than in Tupaia. An anterior intrabullar septum, present in Tupaia, is lacking in Ptilocercus. The epitympanic wing of the alisphenoid is smaller in Ptilocercus than in Tupaia. A lateral prefacial commissure of the tegmen tympani is present in Ptilocercus, but absent in Tupaia. The caudal tympanic process of the petrosal is larger in Ptilocercus than in Tupaia. These characters are autapomorphic for the Ptilocercinae and for the Tupaiinae, respectively. They demonstrate that the auditory bulla of Ptilocercus and that of Tupaia have evolved independently to a considerable extent. An early phylogenetic separation of their respective ancestors seems likely. The tympanic region of the skull provides no evidence for close relationships of the tree shrews to the primates or to any other eutherians. The classification of the Tupaiidae in a separate order, Scandentia, is supported.     

The entotympanic of Equus caballus (Perissodactyla,Mammalia)

In the majority of extant placental mammals the bulla tympanica is composed of two skeletal elements, the entotympanic and the ectotympanic. Former studies revealed that the presence of an entotympanic in the bulla tympanica of extant Perissodactyla is restricted to Rhinocerotidae. The existence of the entotympanic in Tapiridae and Equidae remained speculative. Here we present the first evidence of an entotympanic, strictly speaking rostral entotympanic, in the domestic horse, Equus caballus. The enchondrally ossified entotympanic can be easily separated from the desmal ectotympanic by its greater thickness and by its cancellous bone texture in a late fetal stage. Both elements are separated by a suture that is in the process of coalescence. The complete fusion of the two elements and the unification of bone texture are almost accomplished at birth but the entotympanic and ectotympanic assume the same thickness obviously not until early postnatal development. Based on modern phylogenetic hypotheses we can conclude that the common ancestor of Perissodactyla must have possessed a well-developed entotympanic, probably only evident in their fetal life. This must be considered as a plesiomorphic character state of this order, because the entotympanic is a neomorphic apomorphy of placental mammals. However, the prenatal fusion of the entotympanic and the ectotympanic is an apomorphy of Equus caballus and possibly of the Equidae as a whole.     

菱臼齿兽((犭亚)目、哺乳纲)耳区的骨骼结构

本文详细描述了菱臼齿兽耳区各个部分的基本结构;并指出了耳区结构与某些啮齿类的相似性,以及中耳鼓泡组成成份与戈壁(犭亚)兽(Anagale gobiensis)的区别。     

Defining subregions of Hensen's node essential for caudalward movement, midline development and cell survival.

Hensen's node, also called the chordoneural hinge in the tail bud, is a group of cells that constitutes the organizer of the avian embryo and that expresses the gene HNF-3(&bgr;). During gastrulation and neurulation, it undergoes a rostral-to-caudal movement as the embryo elongates. Labeling of Hensen's node by the quail-chick chimera system has shown that, while moving caudally, Hensen's node leaves in its wake not only the notochord but also the floor plate and a longitudinal strand of dorsal endodermal cells. In this work, we demonstrate that the node can be divided into functionally distinct subregions. Caudalward migration of the node depends on the presence of the most posterior region, which is closely apposed to the anterior portion of the primitive streak as defined by expression of the T-box gene Ch-Tbx6L. We call this region the axial-paraxial hinge because it corresponds to the junction of the presumptive midline axial structures (notochord and floor plate) and the paraxial mesoderm. We propose that the axial-paraxial hinge is the equivalent of the neuroenteric canal of other vertebrates such as Xenopus. Blocking the caudal movement of Hensen's node at the 5- to 6-somite stage by removing the axial-paraxial hinge deprives the embryo of midline structures caudal to the brachial level, but does not prevent formation of the neural tube and mesoderm located posteriorly. However, the whole embryonic region generated posterior to the level of Hensen's node arrest undergoes widespread apoptosis within the next 24 hours. Hensen's node-derived structures (notochord and floor plate) thus appear to produce maintenance factor(s) that ensures the survival and further development of adjacent tissues.     

Morphology and development of the cranium of Felis silvestris f. catus Linné 1758--a contribution to the comparative anatomy of the Carnivora. III: Ear region and occipital region

In Felis, the otic region of younger embryonic stages up to Felis 1 is characterized by extremely medial extended cochleae, compressing the basal plate to a slender trabeculum. As a result of a quite strong rostrad convergence of the long axis of the ear capsules, the Commissura praefacialis fuses with the Commissura orbitoparietalis laterally. Until now, this has been found in whales only. Continuing embryogenesis towards Felis 2, the cochlea moves laterally and slightly ventrally, so the angle of convergence between the whole Capsula otica and the skull base decreases. The problem of interpreting these positional changes of the Capsula otica during phylogenesis and ontogenesis is discussed in detail. Up to recent literature, there is a discussion about homology of the Foramen perilymphaticum and allied structures in reptiles referring to the openings in the Capsula otica in mammals. Configuration of these structures in fissiped carnivores and the appearance of a "limitating membrane" in Felis 2, gives reason for a new discussion of these problems. Composition of the Bulla tympani is a very important feature for investigation of phylogeny and systematics in fissiped carnivores. In Felis 2, there appears a caudal entotympanic, consisting of young cartilaginous tissue. The development of the caudal entotympanic has impact on 2 structures in the occipital region: The Lamina alaris and the Processus paracondyloideus. Felis 1 shows a distinct Lamina alaris and a short Processus paracondyloideus. With Felis 2, either element is reduced largely, probably to the extent as the caudal entotympanic develops.     

MRI Findings of Otic and Sinus Barotrauma in Patients with Carbon Monoxide Poisoning during Hyperbaric Oxygen Therapy

Background and Purpose

To study the MRI findings of otic and sinus barotrauma in patients with carbon monoxide(CO) poisoning during hyperbaric oxygen (HBO) therapy and examine the discrepancies of otic and sinus abnormalities on MRI between barotrauma and acute otitis media with effusion.

Materials and Methods

Eighty patients with CO-poisoning diagnosed with otic and sinus barotrauma after HBO therapy were recruited. Brain MRI was performed to predict delayed encephalopathy. Over the same period, 88 patients with acute otitis media with effusion on MRI served as control. The abnormalities of the middle ear and paranasal sinuses on MRI were noted and were compared between groups. Nine patients with barotrauma were followed up by MRI.

Results

In the barotrauma group, 92.5% of patients had bilateral middle ear abnormalities on MRI, and 60% of patients had both middle ear cavity and mastoid cavity abnormalities on MRI in both ears. Both rates were higher than those in the control group (p = 0.000). In the two groups, most abnormalities on MRI were observed in the mastoid cavity. The rate of sinus abnormalities of barotrauma was 66.3%, which was higher than the 50% in the control group (p = 0.033). In the nine patients with barotrauma followed up by MRI, the otic barotrauma and sinus abnormalities had worsened in 2 patients and 5 patients, respectively.

Conclusion

MRI is able to depict the abnormalities of otic and sinus barotrauma in patients with CO-poisoning during HBO therapy and to differentiate these from acute otitis media with effusion.     

Early steps in neural development

We studied early neurulation events in vitro by transplanting quail Hensen's node, central prenodal regions (before the nodus as such develops), or upper layer parts of it on the not yet definitively committed upper layer of chicken anti-sickle regions (of unincubated blastoderms), eventually associated with central blastoderm fragments. We could demonstrate by this quail-chicken chimera technique that after the appearance of a pronounced thickening of the chicken upper layer by the early inductive effect of neighboring endophyll, a floor plate forms by insertion of Hensen's node-derived quail cells into the median part of the groove. This favors, at an early stage, the floor plate "allocation" model that postulates a common origin for notochord and median floor plate cells from the vertebrate's secondary major organizer (Hensen's node in this case). A comparison is made with results obtained after transplantation of similar Hensen's nodes in isolated chicken endophyll walls or with previously obtained results after the use of the grafting procedure in the endophyll walls of whole chicken blastoderms.     

Identification of chick frizzled-10 expressed in the developing limb and the central nervous system

We have identified chick frizzled (Fz)-10, encoding a Wnt receptor, and examined the expression pattern during embryogenesis. Fz-10 is expressed in the region posterior to the Hensen's node at stage 6. Fz-10 expression is detected in the dorsal domain of the neural tube and the central nervous system of the developing embryo. In the developing limb, Fz-10 expression starts at stage 18 in the posterior-dorsal region of the distal mesenchyme, and gradually expands to the anterior-distal region. Fz-10 is also expressed in the feather bud and branchial arch. Implantation of Sonic hedgehog (Shh)-expressing cells into the anterior margin of the limb bud resulted in the induction of Fz-10 expression in anterior-dorsal mesenchyme.     

Potentialities of temporal bone CT in the diagnosis of chronic purulent otitis media and its complications

Temporal bone CT was used to examine a group of 87 patients with chronic purulent otitis media (103 temporal bones). The patients' age ranged from 2 to 74 years. A scheme was developed and proposed to evaluate the temporal bone by CT. The CT signs of chronic purulent otitis media uncomplicated by cholesteatoma and those of cholesteatomic purulent otitis were identified. The CT symptomatology of chronic purulent otitis includes: sclerotic changes in the bone tissue of the mastoid process, impaired pneumatization of the cavities of the middle ear, including the tympanic cavity, destructive changes in auditory ossicles, carious changes in the walls of the cavities of the middle ear. The CT semiotics of cholesteatoma depends on its site and spread into the temporal bone and includes as follows: deformation of the epitympanum due to soft tissue mass-induced destruction of the lateral wall; the dilated entrance into the antrum; the presence of a cavity with the sclerosed walls in the antromastoid area; carious changes in the auditory ossicles; the displacement of a chain of ossicles medially or laterally in relation to the initial site of cholesteatoma. CT reflects carious changes in the walls of the cavities of the middle ear, including the roof and labyrinthine wall of the tympanum, which allows labyrinthine fistula and intracranial cholesteatomic complications. The study of the temporal bone by the proposed scheme may reveal anomalies and the specific features of its structure: the presentation of the sigmoid sinus, the high elevation of the bulb of the jugular vein, diverticulum of the latter, the low standing of the bottom of the ACH.     

The Entotympanic of Pangolins and the Phylogeny of the Pholidota (Mammalia)

Entotympanics are independent elements present in the auditory bullae of various eutherians. An entotympanic has been reported for extant pangolins of the Order Pholidota, but the actual distribution of this element remains uncertain, in part, because it is a small, loosely attached structure that is often lost in macerated skulls. Consequently, it is unknown whether or not the entotympanic characterizes Pholidota primitively or has evolved within the group. This report addresses the morphology and distribution of the entotympanic among living and extinct pholidotans. An entotympanic occurs in the African pangolins Manis gigantea, M. temminckii, and in one specimen of M. tricuspis. In each, it is a small, nodular bone that occupies a distinct fossa primarily on the basioccipital, the presence of which allows us to assess the occurrence of an entotympanic even in specimens in which the bone has fallen out. Both the entotympanic and the basioccipital facet are lacking in the four remaining extant pangolin species and in the late Eocene pangolin Patriomanis. To assess the significance of this entotympanic distribution, a phylogenetic analysis of extant pangolins plus Patriomanis based on 67 cranial characters was performed. Four different outgroup analyses all resulted in the same single most parsimonious tree, in which the three extant Asian pangolins form a monophyletic clade and the four extant African pangolins fall into a paraphyletic assemblage. Optimization of the entotympanic distribution onto this tree results in two patterns, dependent on the outgroup choice. If Patriomanis is the sole outgroup to the extant pangolins, the entotympanic arises within pangolins as a synapomorphy of Manis gigantea and M. temminckii, convergently acquired in some M. tricuspis. If Xenarthra and Palaeanodonta are employed as outgroups, the entotympanic optimization is ambiguous: the pattern is either as above or the entotympanic is present primitively within Pholidota and lost secondarily in Patriomanis and a clade comprising M. tricuspis, M. tetradactyla, and the Asian forms.     

耳后头皮推进瓣急诊即刻修复创伤性耳郭部分缺损的临床效果观察

目的:探讨耳后头皮瓣急诊即刻修复耳郭部分缺损的可行性与临床效果。方法:对2013年1-12月来我院急诊的7例外伤后耳郭部分缺损的患者(均为男性,年龄22-50岁;其中右耳4例,左耳3例)采用耳后头皮推进瓣即刻修复,以耳郭缺损耳后皮肤及头皮皮肤做推进瓣,将断离的耳郭去皮保留软骨与耳郭断端软骨缝合形成软骨支架,推进皮瓣部分卷曲缝合形成耳轮结构修复耳郭缺损。结果:7例耳郭部分缺损均在急诊环境下即刻修复,耳郭大小和形态满意,颅耳角略变小,随访3~6月耳郭形态稳定。结论:耳后头皮推进瓣卷曲缝合可在急诊条件下即刻修复耳郭部分缺损,具有治疗周期短,一次达到较满意外形的优点,对于无条件行二期手术的患者具有较大意义,其远期效果尚有待进一步随访。     

The entotympanic in late fetal artiodactyla (Mammalia)

The entotympanic is a neomorphic component of the bulla tympanica of placental mammals. Ontogenetically, its rostral component seems to be derived from the tubal cartilage, whereas its caudal component is normally connected with the sheath of the tympanohyal; the present study indicates additional sources of the caudal entotympanic. The entotympanics develop in late fetal or early postnatal life as cartilaginous structures, but in most taxa they ossifiy endochondrally as “os bullae”. This skeletal element is absent only in a few placental orders, among them the Artiodactyla. Because it is present in their sister taxa within the Scrotifera, it is likely to be reduced secondarily in the even‐toed mammals. The study of histological serial sections of late fetal stages of several artiodactyl species shows that vestigial cartilaginous homologues of the entotympanics are invariably present, contrary to statements in the literature. In a few perinatal stages even secondary ossifications or calcifications of the entotympanic cartilages can be observed. The tubal cartilage of artiodactyls also continues into an anterior tegmen tympani (new term) that forms the floor of the fossa muscularis major. J. Morphol. 274:926–939, 2013. © 2013 Wiley Periodicals, Inc.     

Fate mapping and cell lineage analysis of Hensen's node in the chick embryo.

Fate maps of chick Hensen's node were generated using DiI and the lineage of individual cells studied by intracellular injection of lysine-rhodamine-dextran (LRD). The cell types contained within the node are organized both spatially and temporally. At the definitive primitive streak stage (Hamburger and Hamilton stage 4), Hensen's node contains presumptive notochord cells mainly in its anterior midline and presumptive somite cells in more lateral regions. Early in development it also contains presumptive endoderm cells. At all stages studied (stages 3-9), some individual cells contribute progeny to more than one of these tissues. The somitic precursors in Hensen's node only contribute to the medial halves of the somites. The lateral halves of the somites are derived from a separate region in the primitive streak, caudal to Hensen's node.     

Computed tomography in the diagnosis of exudative otitis media

Temporal bone computed tomography (CT) was used to examine 37 patients aged 2 to 55 years who had exudative otitis media; in 27 patients of them, a pathological process was bilateral. An analysis of 58 temporal bone CT scans identified the CT signs of chronic exudative otitis media. These included a partial or complete block of the osseous foramen of the auditory tube; impaired pneumatization of the tympanic cavity, mastoid process fenestrae, and antrum; pathological drawing-in of the tympanic membrane. The preservation of the auditory ossicles and the absence of destructive changes in the walls of the cavities of the middle ear were observed in most cases. Repeated temporal bone CT study was performed in 10 patients (14 temporal bones) in different periods (from 2 months to 3 years) after surgery. The results of tympanostomy were visually assessed. These included recovered pneumatization of middle ear cavities (7 temporal bones), a cicatricial process in the tympanic cavity (5 temporal bones), recurrence of the CT manifestations of exudative otitis media (2 temporal bones).     

Imaging electrically evoked micromechanical motion within the organ of corti of the excised gerbil cochlea

The outer hair cell (OHC) of the mammalian inner ear exhibits an unusual form of somatic motility that can follow membrane-potential changes at acoustic frequencies. The cellular forces that produce this motility are believed to amplify the motion of the cochlear partition, thereby playing a key role in increasing hearing sensitivity. To better understand the role of OHC somatic motility in cochlear micromechanics, we developed an excised cochlea preparation to visualize simultaneously the electrically-evoked motion of hundreds of cells within the organ of Corti (OC). The motion was captured using stroboscopic video microscopy and quantified using cross-correlation techniques. The OC motion at approximately 2-6 octaves below the characteristic frequency of the region was complex: OHC, Deiter's cell, and Hensen's cell motion were hundreds of times larger than the tectorial membrane, reticular lamina (RL), and pillar cell motion; the inner rows of OHCs moved antiphasic to the outer row; OHCs pivoted about the RL; and Hensen's cells followed the motion of the outer row of OHCs. Our results suggest that the effective stimulus to the inner hair cell hair bundles results not from a simple OC lever action, as assumed by classical models, but by a complex internal motion coupled to the RL.     

Hensen's node induces neural tissue in Xenopus ectoderm. Implications for the action of the organizer in neural induction.

The development of the vertebrate nervous system is initiated in amphibia by inductive interactions between ectoderm and a region of the embryo called the organizer. The organizer tissue in the dorsal lip of the blastopore of Xenopus and Hensen's node in chick embryos have similar neural inducing properties when transplanted into ectopic sites in their respective embryos. To begin to determine the nature of the inducing signals of the organizer and whether they are conserved across species we have examined the ability of Hensen's node to induce neural tissue in Xenopus ectoderm. We show that Hensen's node induces large amounts of neural tissue in Xenopus ectoderm. Neural induction proceeds in the absence of mesodermal differentiation and is accompanied by tissue movements which may reflect notoplate induction. The competence of the ectoderm to respond to Hensen's node extends much later in development than that to activin-A or to induction by vegetal cells, and parallels the extended competence to neural induction by axial mesoderm. The actions of activin-A and Hensen's node are further distinguished by their effects on lithium-treated ectoderm. These results suggest that neural induction can occur efficiently in response to inducing signals from organizer tissue arrested at a stage prior to gastrulation, and that such early interactions in the blastula may be an important component of neural induction in vertebrate embryos.