Tetracycline marks visible in Baltic cod Gadus morhua otoliths stored for 40 years

Baltic cod Gadus morhua otoliths marked with oxytetracycline (OTC) in 1974-1975 had been sectioned and the sections stored in paper envelopes at room temperature in dry, dark conditions. After 40 years of storage, the historic OTC marks were still clearly visible showing that OTC is suitable for long-term chemical marking of otoliths. They were, however, noticeably paler than marks in recently recaptured and archived Baltic G. morhua otoliths, chemically tagged with tetracycline at similar dosage to the historic otoliths.

Automated otolith image classification with multiple views: an evaluation on Sciaenidae

Combined multiple 2D views (proximal, anterior and ventral aspects) of the sagittal otolith are proposed here as a method to capture shape information for fish classification. Classification performance of single view compared with combined 2D views show improved classification accuracy of the latter, for nine species of Sciaenidae. The effects of shape description methods (shape indices, Procrustes analysis and elliptical Fourier analysis) on classification performance were evaluated. Procrustes analysis and elliptical Fourier analysis perform better than shape indices when single view is considered, but all perform equally well with combined views. A generic content-based image retrieval (CBIR) system that ranks dissimilarity (Procrustes distance) of otolith images was built to search query images without the need for detailed information of side (left or right), aspect (proximal or distal) and direction (positive or negative) of the otolith. Methods for the development of this automated classification system are discussed.

Three-dimensional rendering of otolith growth using phase contrast synchrotron tomography

A three-dimensional computer reconstruction of a plaice Pleuronectes platessa otolith is presented from data acquired by the Diamond Light synchrotron, beamline I12, X-ray source, a high energy (53-150 keV) source particularly well suited to the study of dense objects. The data allowed non-destructive rendering of otolith structure, and for the first time allows otolith annuli (internal ring structures) to be analysed in X-ray tomographic images.

Three-dimensional cone beam computed tomography imaging of the membranous labyrinth in patients with Meniere's disease

CONCLUSION

Three-dimensional cone beam computed tomography (3DCT) images revealed characteristic malformations of the membranous labyrinth of the inner ear in Meniere's disease (MD). The morphology of the membranous region between the vestibular cecum of the cochlea and the saccule of ears with MD was compared to that of healthy ears. The present study supports the hypothesis proposed earlier that reuniting duct blockade is a result of the dislodgement of saccular otoconia.

OBJECTIVE

To visualize the membranous labyrinth using 3DCT and to investigate the pathology of MD.

METHODS

A preparatory study was conducted to determine the optimal 3DCT window settings for the detection of water, muscle, calcium carbonate (CaCO3), and bone. Based on this preparatory study, the ears of 13 healthy volunteers and 25 MD patients definitely diagnosed according to the criteria issued by the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology, Head and Neck Surgery (AAO-HNS), were visualized.

RESULTS

The differences in the membranous labyrinth between MD ears and healthy ears could be visualized using 3DCT. The images were classified into three types based on their morphological pattern. The ears of patients with MD were different from normal ears in terms of this classification.

Blockage pattern of longitudinal flow in Meniere's disease

CONCLUSION

In the present study, classification of the patterns of 3D CT images of the ductus reuniens (reuniting duct) (RD), saccular duct (SD), and endolymphatic sinus (ES) gave more precise information for assessing the pathological condition of Meniere's disease (MD) than our previous study.

OBJECTIVE

This study attempted to provide more detailed information on MD by classifying the patterns of 3D CT images of the RD, SD, and ES in patients with MD.

METHODS

We examined the ears of 62 patients with definitely diagnosed unilateral MD based on the criteria of the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) using 3D CT. The 3D CT images of bony grooves of RD, SD, and ES (BRD, BSD, and BES) were classified into patterns according to aspects of their patency.

RESULTS

BRD could be classified into six types by assessing their patency defined using the criteria in this study. In the ears on the affected side of patients with MD, the BRD, BSD, and BES lost continuity in 3D CT images along their bony routes and were significantly different from normal healthy ears (p < 0.01). There were no significant differences among each stage of MD in the distributions of BRD and BES except for BSD.

Assessment of Meniere's disease from a radiological aspect - saccular otoconia as a cause of Meniere's disease?

CONCLUSION

Significant reduced visualization of the reuniting duct (ductus reuniens; RD), saccular duct (SD) and endolymphatic sinus (ES) in Meniere's disease (MD) compared with normal control ears on three-dimensional (3D) CT imaging suggests the blockage of endolymphatic flow there with radiodense substances, which may be explained by dislodged otoconia from the saccule. These structures could be involved in the pathogenesis of MD.

OBJECTIVE

This study was designed to visualize and assess the RD, SD and ES in patients with MD using 3D CT.

METHODS

Sixty-two patients with a definite diagnose of unilateral MD, based on criteria proposed by the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS), were compared with contralateral ears and normal controls (26 ears) using 3D CT. The RD, SD and ES were scrutinized for patency on 3D CT images.

RESULTS

MD ears showed loss of continuity of the RD, SD and ES based on evaluation of 3D CT images, and differed significantly from normal healthy control ears (p < 0.01).

Acoustically induced streaming flows near a model cod otolith and their potential implications for fish hearing

The ears of fishes are remarkable sensors for the small acoustic disturbances associated with underwater sound. For example, each ear of the Atlantic cod (Gadus morhua) has three dense bony bodies (otoliths) surrounded by fluid and tissue, and detects sounds at frequencies from 30 to 500 Hz. Atlantic cod have also been shown to localize sounds. However, how their ears perform these functions is not fully understood. Steady streaming, or time-independent, flows near a 350% scale model Atlantic cod otolith immersed in a viscous fluid were studied to determine if these fluid flows contain acoustically relevant information that could be detected by the ear's sensory hair cells. The otolith was oscillated sinusoidally at various orientations at frequencies of 8-24 Hz, corresponding to an actual frequency range of 280-830 Hz. Phase-locked particle pathline visualizations of the resulting flows give velocity, vorticity, and rate of strain fields over a single plane of this mainly two-dimensional flow. Although the streaming flows contain acoustically relevant information, the displacements due to these flows are likely too small to explain Atlantic cod hearing abilities near threshold. The results, however, may suggest a possible mechanism for detection of ultrasound in some fish species.

Blockage of reuniting duct in Meniere's disease

CONCLUSION

The bony saccular orifice to the bony groove of the ductus reuniens (reuniting duct) could not be visualized in the Meniere's ear with significantly greater frequency compared with normal subjects, which suggests that the reuniting duct is affected by radio-opaque substances in CT findings.

OBJECTIVE

This study investigated a more specific, objective, and simpler strategy to diagnose Meniere's disease by assessing the reuniting duct.

SUBJECTS AND METHODS

We examined the ears of 12 patients with definitely diagnosed unilateral Meniere's disease in stage 3 based on Meniere's disease criteria proposed by the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS), and the ears of 12 normal control subjects using three-dimensional (3D) cone beam CT.

RESULTS

The bony groove of the reuniting duct between the saccule and cochlea was visualized in all control subjects. However, the bony saccular orifice to the bony groove could not be visualized in the lesional ear of Meniere's patients with significantly greater frequency compared with those of the contralateral non-lesional ears and control ears (p < 0.01). This orifice was not patent in 66.7% (8 of 12 ears) on the lesional side but all contralateral non-lesional ears of the patients and normal control ears were patent.

Otolithiasis in three dogs

Mineral opacities within the tympanic bullae, termed otoliths, were detected in three dogs by means of radiography and computed tomography. Radiographic signs of otitis externa were present in two dogs. One dog had clinical signs of vestibular disease, whereas the other two dogs had no clinical evidence of ear disease. Otolithiasis may represent mineralized necrotic material of a current or previous case of otitis media.

The otoliths of the antarctic teleost Trematomus bernacchii: scanning electron microscopy and X-ray diffraction studies

The authors studied the otoliths of the Nototheniid Trematomus bernacchii with scanning electron microscopy and X-ray diffraction analysis. Results obtained reveal that three otoliths are present: a large sagitta, a lapillus and a fragile asteriscus. Their sensorial faces appear finely decorated as shown by scanning electron microscopy (SEM). The sagitta and the lapillus are aragonitic while the asteriscus is vateritic, as demonstrated by X-ray diffraction.

Crystallographic and chemical composition of otoconia in the salamander Pleurodeles waltl

The aim of the present study was to define the morphology and the crystallographic and chemical composition of otoconia in different regions of the inner ear in Pleurodeles waltl (urodele amphibian). The inner ear of adults was microdissected and otoconia were analyzed by scanning electron microscopy (SEM), X-ray diffraction, energy dispersive X-ray (EDX) and transmission electron microscopy. Two types of crystals were detected by SEM. Otoconia had different shapes depending on their location in the membranous labyrinth. One type had a cylindrical body with a triplanar smooth facet at each end, the other ones had either a prismatic shape with flat sides and end faces or a fusiform shape with rounded body and pointed end. The forms corresponded to those previously identified by other authors. These two types of otoconia had different X-ray diffraction patterns. The cylindrical otoconia were calcitic and located in the utricle, the other ones were aragonitic and located in the saccule, lagena and endolymphatic sac. An analysis by EDX indicated that both types of otoconia contained about 95% calcium with trace quantities of sodium, magnesium, phosphorus, sulfur, chlorine and potassium. Trace amounts of strontium was only found in the aragonitic otoconia.

Non-invasive assessment of otolith formation during development of the Japanese red-bellied newt, Cynops pyrrhogaster

Pre-mated adult female newts and embryos have been flown on the International Microgravity Laboratory-2 (IML-2) Space Shuttle flight in 1994 (Wiederhold et al., 1992b). With the specimens available from this flight, the calcification of otoliths, ulna, radius and backbone of the flown larvae and adult newts were analyzed. The experiments presented here studied the development of the otoliths on the ground. Otoliths of living newts, from embryo to adult, were observed in situ with the application of a new X-ray and bio-imaging analyzer system. For the establishment of this method, newts at different developmental stages were used. An imaging plate temporarily stores the X-ray energy pattern at the bio-imaging analyzer. A latent image on the imaging plate was transformed into a digital time series signal with an image reader. Acquired digital information was computed with the image processor. The processed information was recorded on film with an image recorder, in order to visualize it on an enlargement computed radiograph. To analyze development of the otoliths, photo-stimulated luminescence level was detected by an image analyzer, using transmitted X-ray photons. A single clump of otoconia could first be seen at stage 33. Stage-36 embryos first have distinguishable otoliths, with the utricle in front and saccule behind. Our results show that this X-ray method detects the otoliths equally as well as sectioning. In the newt, the mandibular/maxillary bone formed before the spine. It is suspected that for the newt embryo, living in water, feeding becomes necessary prior to support of the body.