Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Incus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed1996

Bilateral congenital cholesteatoma.

We report a case of bilateral congenital cholesteatoma in a 6-year-old boy. Cholesteatoma was present in both ears around the tympanic isthmus (the only open passage from the tympanic cavity to the attic), extending to behind the horizontal portion of the facial nerve. This patient underwent a total of three canal wall up operations on each side to remove the cholesteatoma completely and improve hearing. This case fulfills the criteria proposed by Derlacki and Clemis in 1965. Bilateral congenital cholesteatoma is a rare condition, but the incidence of congenital cholesteatoma in children has increased recently for the following reasons: Reassessment of the criteria, the introduction of computed tomography, and increased awareness of congenital cholesteatoma. When operating on patients with bilateral cholesteatoma, the best method for preservation of hearing should be chosen. We discuss these problems in the present report.

Cartilage↗
PubMed1999

Maintenance of regional histodifferentiation patterns and a spatially restricted expression of type X collagen in rat Meckel's cartilage explants in vitro.

The major, central portion of Meckel's cartilage undergoes fibrous transformation and contributes to the sphenomandibular ligament, whereas its distal end undergoes endochondral ossification ultimately giving rise to inner-ear ossicles. This regional histodifferentiation of Meckel's cartilage is known to be associated with the spatially restricted expression of type X collagen. The objective of this study was to determine if this unique histodifferentiation is regulated by local environmental factors or by a preprogrammed genetic mechanism. Meckel's cartilage, and condylar cartilage used for comparison, were isolated from 17-day-old rat embryos and from newborn rats, respectively. The cartilage explants were maintained in vitro for 50 days with or without supplementation with 10% fetal bovine serum. When the explants were cultured under serum-free conditions, well-regulated cartilage development was observed. Expression of type X collagen, a differentiation marker for hypertrophic cartilage, was restricted to the distal end of Meckel's cartilage, whereas type II and IX collagens were found uniformly along the entire explant. Matrix calcification was examined histochemically using alizarin red S staining and found to be restricted to the distal end of Meckel's cartilage. Both Meckel's and condylar cartilage cultured with 10% fetal bovine serum developed unregulated dysmorphogenesis. These data suggest that, although Meckel's cartilage has an intrinsic potential to differentiate to its terminal stage, external regulatory factors can significantly influence its normal development at the molecular level.

Animals↗
PubMed1999

Biomechanical properties of sterilized human auditory ossicles.

Bone allograft material is treated with sterilization methods to prevent the transmission of diseases from the donor to the recipient. The effect of some of these treatments on the integrity of the bone is unknown. This study was performed to evaluate the effect of several sterilization methods on the mechanical behaviour of human middle ear bones. Due to the size and composition of the bones (approximately 1.5 mm diameter by 4 mm long), mechanical testing options were limited to the traditional platens compression test. Experiments were first performed with synthetic bone to evaluate the precision of this test applied to small specimens. Following this, fresh frozen human ossicles were thawed and sterilized with (i) 1 N NaOH (n = 12); (ii) 0.9% LpH, a phenolic solution (n = 12); or (iii) steam at 134 degrees C (n = 18). A group of 26 control specimens did not receive any sterilization treatment. Material and structural properties were determined from axial compression testing. Results from the synthetic bone showed that the test was reproducible, with standard deviations less than 20% of the means. Significant differences occurred in stiffness and ultimate force values between NaOH-treated and autoclaved bones when compared to normals (p<0.05), but not for LpH-treated bones. LpH is not approved for medical use, so NaOH is the most appropriate of the treatments studied for the sterilization of ossicle allografts.

Analysis of Variance↗
PubMed1997

Surgical anatomy of the rat middle ear.

This study was designed to aid experimental otologic studies of the rat middle ear. The topographic anatomy of the albino rat middle ear is described. A set of microphotographs with matching illustrations presents the structural details at several surgical exposures. Anatomic differences between the rat, guinea pig, and cat are noted.

Anatomy, Comparative↗
PubMed1997

Anomalously coursing facial nerves above and below the oval window: three case reports.

Anomalous coursing of a dehiscent horizontal segment of the facial nerve, overlying or running below the oval window, is a rare phenomenon exclusively associated with conductive deafness caused by developmental abnormalities of the stapes and occasionally coincident with additional types of congenital auricular and nonauricular abnormalities. This article describes three new cases of this entity, including one previously unreported coincidence of an abnormally contracted tympanic ring, which should serve to alert the surgeon to the danger of surgical damage to a dehiscent, displaced facial nerve.

Adult↗
PubMed1975

Prebycusis: physiological or pathological.

A study was made on human temporal bones to elucidate the effects of aging on the auditory system. Ninety-six ears from 68 individuals, varying in age from infancy to 84 years, served as 'normal ears'. None of these cases had clinical or pathological evidence of specific ear diseases. 'Pathological ears' consisted of 89 ears from 58 individuals which exhibited slowly progressive hearing loss, and which had no specific known cause for the loss. Two aging phenomena were found to affect the human ear. The first is physiological, and has been called 'auditory senility'. It involves all the different parts of the auditory mechanism equally, and is responsible for the rise in auditory thresholds for the high frequencies, commonly seen in elderly people. The second phenomenon is pathological, and was termed 'auditory decay'. It involves only the perceptive system of the ear, and results in different types of clinical presentations, according to the morphological layer involved. Therefore, the recognition of two aging phenomena which affect the human ear may explain the reason for the wide variations in auditory acuity associated with old age.

Adolescent↗