Biomedical subjects

P A Schachern

Publications and source records attributed to P A Schachern.

At least 19 recordsLinked to original sources

PubMed1996

Temporal bone study of Down's syndrome.

OBJECTIVE: To study temporal bone histopathologic characteristics of the inner ear and middle ear cleft of patients with Down's syndrome. DESIGN: Sixteen temporal bones from eight patients with Down's syndrome were studied. Ten temporal bones from subjects without pathologic ear lesions but with congenital heart disease served as controls. The two-dimensional graphic reconstruction method proposed by Guild and modified by Schuknecht was used to study the cochleas; measurement of the vestibules was based on Igarashi's method. SETTING: The temporal bone collection of the Otitis Media Research Center, Department of Otolaryngology, University of Minnesota School of Medicine, Minneapolis. RESULTS: Six bones showed short cochlea, and four of six had Mondini's cochlea. The overall cochlear lengths in this study group were notably shorter than those of the controls. The spiral ganglion cell population and two of three vestibular dimensions also were notably less than the controls. Middle ear findings included residual mesenchyme, stapes abnormality, otitis media, and large facial canal dehiscence. CONCLUSIONS: The difficulties encountered in rehabilitation of patients with Down's syndrome caused by mental retardation can be compounded by the hearing loss caused by middle and inner ear abnormalities. A complete evaluation of hearing loss and therapy before starting the rehabilitation gives the most favorable outcome.

Adolescent↗

PubMed1996

Developmental anatomy of the supratubal recess in temporal bones from fetuses and children.

The supratubal recess (STR), located superior to the bony eustachian tube and anterior to the attic and often the site of disease, is clearly separated from the attic by the presence of a bony partition. Its anatomic development in childhood, however, remains nuclear. We reviewed serial horizontal sections of fetal and children's temporal bones from the collection of the Otopathology Laboratory, University of Minnesota. Apparently, upward expansion of the bony eustachian tube begins at a late fetal stage and continues throughout childhood, thus forming the STR. Our finding that the STR had already developed in temporal bones without pneumatization of petrous bone suggests that its formation is independent of the air-cell system. Absorption of mesenchymal tissue in the STR tends to be slower than elsewhere in the temporal bone. Surrounded solely by petrous bone, the STR seems, both developmentally and anatomically, a distinctive compartment of the middle ear.

Child↗

PubMed1994

Micropathologic changes of pars tensa in children with otitis media with effusion.

Clinical studies have supported a relationship between otitis media with effusion in children and chronic otitis media in adults. Although clinical studies are numerous, relatively little is known about the histopathologic changes of the tympanic membrane in otitis media with effusion. Tympanic membranes were taken from the intermediate zone of the anteroinferior quadrant of the tympanic membrane during surgery for placement of tympanostomy tubes in 30 children (age range, 4 to 10 years) who did not show any improvement after 3 months of conservative treatment for otitis media with effusion. Control specimens were taken from normal temporal bones at autopsy. All specimens were observed with light and electron microscopy. Histologic degeneration of the tympanic membrane of patients with otitis media with effusion occurred most often in the lamina propria and the submucosal layer. There was an increase in the thickness of the tympanic membrane as a result of edema and fibrosis of the submucosal layer. A decrease in the thickness of the outer and inner fibrous layers occurred in the lamina propria. The histopathologic changes observed in the lamina propria may result in a change in the elastic properties of the tympanic membrane.

Adult↗

PubMed1994

Cytokeratin patterns of normal middle ear epithelia in humans, cats, and chinchillas.

We describe the cytokeratin patterns of epithelia from the tympanic orifice, tympanic cavity, and mastoid cavity of humans, cats, and chinchillas, and compare these findings with those of tracheal epithelium and external canal epidermis. Our findings are as follows: 1) middle ear epithelium from all locations demonstrates some type of cytokeratin staining, 2) broad-spectrum cytokeratin antibodies stain epithelia of middle ear cleft, tracheal epithelium, and external canal epidermis in all species, 3) specific cytokeratin antibodies reveal species-related differences in middle ear and tracheal epithelia, 4) middle ear and tracheal epithelia usually have the same pattern, and 5) none of the monospecific cytokeratin antibodies have a positive reaction with external canal epidermis. These findings suggest that the cytokeratin patterns of middle ear epithelium are useful in studying the hyperplastic and metaplastic changes in otitis media; however, caution must be exercised when making interspecies comparisons.

Animals↗

PubMed1994

The temporal bone in multiple myeloma.

Multiple myeloma is a malignant disease of the skeleton. Anatomically, any bone may ultimately come to be involved in a given case. In a literature review, no published series of temporal bone findings have been reported. In this study, oto-histopathologic changes associated with multiple myeloma are analyzed and reported in 15 temporal bones from 8 patients. The bone marrow of 13 temporal bones was involved by the tumor. Osteolysis was evident in 11 temporal bones. Serous otitis media (SOM) or purulent otitis media (POM) was seen in 13 ears with 12 showing mastoid effusions. Eight ears exhibited pathological changes in inner ears, including degeneration of the organ of Corti, atrophy of stria vascularis, decreased ganglion cells, and labyrinthine hydrops. The inner ear changes were most severe in 2 patients who had otologic symptoms. Infiltration of myeloma cells was not apparent in the middle ear mucosa or the inner ears.

Aged↗

PubMed1994

Otitis media (silent): a potential cause of childhood meningitis.

Sixteen temporal bones from 8 infants with otitis media, who died of meningitis, and 6 controls from infants with only otitis media, were studied histologically. All bones contained middle ear effusion and residual mesenchyme, but, unlike the controls, the meningitic cases showed considerable histopathological tissue changes of chronic and acute otitis media and chronic inflammatory cells in the round window membrane and within the perilymph, the modiolus, and the cochlear aqueduct, suggesting the latter as likely portals from the inner ear to the meninges. Since all tympanic membranes were intact and 3 were histologically normal, this silent route of infection warrants medical vigilance.

Acute Disease↗

PubMed1993

Pathogenesis of tympanosclerosis.

In spite of the wealth of information on the clinical, histologic, and pathologic aspects of tympanosclerosis, the pathogenesis of tympanosclerosis is still unclear. In an attempt to understand the pathogenesis, 319 human temporal bones from 196 individuals with otitis media were studied. The extent and nature of tympanosclerosis and the characteristics of the otitis media associated with it were studied. Forty-five temporal bones from 35 individuals with otitis media were found to have tympanosclerosis, giving an incidence of 14.1%. It was seen most commonly in individuals over 40 years of age (86.7%). The male-to-female ratio was 1.6:1. The most common site of occurrence was the tympanic membrane (88.9%). Tympanosclerosis was seen more often in the anterior and posterior inferior quadrants of the tympanic membrane and that, too, in a central position. Tympanosclerosis was seen more commonly in temporal bones with irreversible inflammatory changes, and in this group, late plaques were more commonly seen than early or intermediate plaques. Audiometric charts failed to show any direct relationship between extent of tympanosclerosis and the severity of hearing loss. The only audiometric finding of any consequence was a mixed hearing loss in the presence of middle ear tympanosclerosis.

Adult↗

PubMed1992

Bacterial tympanogenic labyrinthitis, meningitis, and sensorineural damage.

Pathologic changes (sensorineural hearing loss, labyrinthitis, meningitis) can follow otitis media. Various macromolecular substances demonstrably enter the inner ear via the round window membrane, but its permeability to bacteria is less known. We inoculated Streptococcus pneumoniae type 7F bilaterally into the middle ears of two groups of chinchillas, with and without grafted round window membranes. Inner ears of inoculated animals were observed by light and electron microscopy. None with continuous grafts had labyrinthitis. Bacteria penetrated all three layers of nongrafted round window membranes and into all cochlear turns, entering Schuknecht's channels and following neuronal pathways; nerves were often degenerated, hair cells were damaged or missing, and the stria vascularis was edematous and hemorrhagic. The neural damage suggests a mechanism for the hearing loss that can follow otitis media. Absence of labyrinthitis and meningitis in grafted animals suggests a tympanogenic pathway for the bacteria.

Animals↗

PubMed1992

Mechanisms of retraction pocket formation in the pediatric tympanic membrane.

The epidemiological nature of acquired cholesteatoma in children has shown that it occurs more often in the posterosuperior quadrant of the pars tensa and in the pars flaccida. This type of cholesteatoma is rarely seen before the age of 3 years, and serous otitis media is the most important risk factor for its occurrence. In an attempt to present a pathological rationale for these clinical findings, tympanic membranes from 11 temporal bones with purulent otitis media and 13 with serous otitis media were evaluated light microscopically and compared with 14 temporal bones without disease. Ages ranged from newborn to 3 years 6 months. The persistence of mesenchyme and greater inflammatory reaction observed in the pars flaccida and the posterosuperior quadrant of the pars tensa and changes in collagen and elastin observed in purulent otitis media and serous otitis media may represent a pathological rationale for the epidemiological nature of cholesteatoma in children.

Age Factors↗

PubMed1992

Temporal bone histopathology in chronically infected ears with intact and perforated tympanic membranes.

Chronic suppurative otitis media has been clinically defined as a chronic discharge from the middle ear in the presence of a perforation of the tympanic membrane. However, irreversible tissue pathology in the middle ear or mastoid can occur behind an intact tympanic membrane. One hundred forty-four human temporal bones with chronic otitis media were divided into two groups: those with perforated (28) and those with nonperforated (116) tympanic membranes. The histopathological findings of their middle ears were compared. Granulation tissue in various degrees was the most prominent pathological feature. It was observed in 96% of temporal bones with perforation of the tympanic membrane, and in 97% of those without perforation. Also found were ossicular bony changes (96% with perforation; 90.5% without), middle ear effusion (93% with perforation; 89% without), cholesterol granuloma (21% with perforation; 12% without), cholesteatoma (36% with perforation; 4% without), and tympanosclerosis (43% with perforation; 20% without). This study shows that the histopathological changes of the middle ear are similar in temporal bones with and without perforation of the tympanic membrane. The clinician should, therefore, be aware that an intact tympanic membrane does not necessarily preclude the presence of gross pathological changes of the middle ear cleft.

Adolescent↗

PubMed1991

Age-related morphologic changes in the human tympanic membrane. A light and electron microscopic study.

To our knowledge, the normal changes that occur in the tympanic membrane after birth have not been described, despite several reports that their otoscopic appearance in healthy, full-term infants is different from that in adults. To provide such a description, the tympanic membranes of 54 temporal bones that had no pathologic evidence of otologic diseases, from patients aged 33 weeks' gestation to 91 years, were examined with light or electron microscopy. The changes encountered in thickness, cellularity, vascularity, collagen, and elastin indicated beyond the first year of life and into old age.

Adolescent↗

PubMed1991

Cellular changes in Reissner's membrane in endolymphatic hydrops.

A quantitative morphologic study of the cellular changes in human Reissner's membrane (RM) was performed under light microscopy on 30 normal temporal bones from 15 subjects, and on 20 temporal bones from 10 subjects with endolymphatic hydrops. The cellular density of the epithelial and mesothelial layers of normal RMs decreased with increasing age. In endolymphatic hydrops, cellular proliferation and decreased cellular density of a distended RM were observed, and these changes occurred more remarkably in epithelial cells. Decreased cellular density in RM was correlated to the degree of endolymphatic hydrops. These findings indicate an involvement of the epithelial cellular changes in the pathogenesis of endolymphatic hydrops. Our results suggest that cellular changes in RM may cause dysfunction of radial flow leading to ionic disturbance of endolymph, which provides a possible mechanism of hearing loss in endolymphatic hydrops.

Adolescent↗

PubMed1990

Histopathology of the tensor tympani muscle in otitis media.

Involvement of the tensor tympani muscle (TTM) and tendon in otitis media have been suggested both clinically and experimentally. Extensive postmortem histopathological studies of the human TTM in cases with known otitis media have not been done. One-hundred-five human temporal bones with and without otitis media were evaluated using light microscopy to determine the pathological changes of the TTM and tendon. Fatty cell infiltration and degenerative changes of the muscle fibers were observed in non-otitis and otitis media groups, but were greater in those cases with otitis media. Inflammatory cell infiltration and fibroblastic reactions occurred more often in chronic and purulent otitis media, and hypercontracted fibers were more frequent in serous and chronic otitis media. This study indicates that the human TTM and tendon are pathologically involved in the inflammatory process of otitis media.

Adolescent↗

PubMed1990

Otopathologic correlates of the continuum of otitis media.

It has been our hypothesis that different types of middle ear effusions and the clinical manifestations with which they are associated represent the typical inflammatory response. Employing an animal model under controlled conditions, we present statistical evidence that change in the mucosa of the middle ear in otitis media can occur along a continuum, with early forms regressing to more chronic stages of the disease. We also demonstrate an increase in the thickness and a decrease in the permeability of the round window membrane in a longitudinal study of otitis media in the same animal model. Histopathologic changes in human temporal bones with otitis media with effusion or chronic otitis media are similar to the changes in the animal models. These results support a concept that all categories of otitis media (serous, purulent, mucoid, and chronic) represent different stages in a continuum of events.

Adolescent↗

PubMed1990

Morphometric studies of the continuum of otitis media.

Morphometric changes in the epithelium and subepithelium of the middle ear mucosa from children younger than 10 years of age were measured at the promontory in 85 temporal bones with otitis media and in 29 normal temporal bones by use of quantitative and semiquantitative methods. Comparisons of morphologic analysis in different otitis media types showed that acute inflammatory changes were usually seen in purulent otitis media with effusion and serous otitis media with effusion, and chronic inflammatory changes were more severe in mucoid otitis media with effusion and chronic otitis media. There were overlaps, however, in histopathologic findings between different types of otitis media that suggest a continuum of otitis media types, with one type of otitis media changing into another type.

Child↗

PubMed1990

Otosclerosis involving the vestibular aqueduct and Menière's disease.

The coexistence of otosclerosis and endolymphatic hydrops in the temporal bone have been described; however, the mechanism for the development of endolymphatic hydrops in otosclerosis remains unknown. Among 128 temporal bones with otosclerosis, involvement of the vestibular aqueduct by otosclerosis was observed in four temporal bones from two patients. In all four, the vestibular aqueduct was filled with active otosclerotic foci; the lumen of the endolymphatic duct and sac was narrowed as a result of fibrosis, and endolymphatic hydrops, more severe in the pars inferior than the pars superior, was observed. Collapse of the ductus reuniens and dilated saccule was seen in three temporal bones. Our study indicates that otosclerotic obstruction of the vestibular aqueduct may create a disturbance of the outflow and/or absorption of endolymph, leading to the development of endolymphatic hydrops and Meniere's disease, thus supporting the theory of longitudinal flow of endolymph.

Aged↗

PubMed1990

Histopathology of sudden hearing loss.

Eleven temporal bones from eight patients who had clinical histories of sudden hearing loss (SHL) were studied to assess the possible etiopathogenesis. The origin of SHL in seven ears from five patients was obscure, but appeared to be due to multiple causes. Common histopathologic changes in the cochlea, although complex, included atrophy of the organ of Corti and loss of cochlear neurons. Loss of cochlear neurons was the main finding in ears of viral infection. Labyrinthine fibrosis and formation of new bone were seen in two ears associated with vascular insult and in two ears of autoimmune disease. Different histopathologic findings causing SHL were observed even in cases with the same etiology. A case of SHL showing endolymphatic hydrops as the main histopathologic finding is described.

Adolescent↗

PubMed1989

Otologic histopathology of Fabry's disease.

Fabry's disease is a rare progressive X-linked recessive disorder of glycosphingolipid metabolism. The accumulation of glycosphingolipids occurs in virtually all areas of the body, including the endothelial, perithelial, and smooth-muscle cells of blood vessels, the ganglion cells of the autonomic nervous system, and the glomeruli and tubules of the kidney. Although otologic symptoms have been described in these patients, to our knowledge there have been no temporal bone histopathologic reports. We describe the clinical histories, audiometric results, and temporal bone findings of two patients with this rare disorder. Both patients demonstrated a bilateral sloping sensorineural hearing loss audiometrically. Middle ear findings of seropurulent effusions and hyperplastic mucosa were seen in all four temporal bones. Strial and spiral ligament atrophy in all turns, and hair cell loss mainly in the basal turns, were also common findings. The number of spiral ganglion cells was reduced in all temporal bones; however, evidence of glycosphingolipid accumulation was not observed in the spiral ganglia.

Audiometry↗