Analysis of the Hyalinization Reaction in Otosclerosis.

Importance: Otosclerotic bone has been observed to penetrate the endosteal layer of the cochlea, resulting in direct contact with the soft-tissue structures of the inner ear. Sensorineural hearing loss has been observed in some, but not all, of these cases. The development of histologic changes occurring in the cochlear soft tissues at the site of otosclerotic endosteal penetration has been descriptively referred to as a hyalinization reaction.

Cochlear nucleus neuron analysis in individuals with presbycusis.

Objectives/hypothesis: The aim of this study was to analyze the cochlear nucleus neuron population in individuals with normal hearing and presbycusis.

Study Design: Retrospective study of archival human temporal bone and brain stem tissues.

Methods: Using strict inclusion criteria, the temporal bones and cochlear nuclei from six normal hearing individuals and four individuals with presbycusis were selected for analysis.

Duplex real-time PCR assay for quantifying mitochondrial DNA deletions in laser microdissected single spiral ganglion cells.

Laser microdissection (LMD) has been used to isolate groups of cells and single cells from numerous tissues. In this chapter, we describe a technique for isolating individual spiral ganglion cells from archival formalin-fixed, celloidin-embedded (FFCE) human temporal bone sections. The DNA isolated from these single cells is suitable for analysis with a duplex real-time polymerase chain reaction (PCR) methodology to quantify the mitochondrial DNA (mtDNA) deletion level present.

Dual immunofluorescence staining of proteoglycans in human temporal bones.

Objectives/hypothesis: Immunofluorescence staining methods have been developed to study the distribution of macromolecules in archival formalin-fixed celloidin-embedded human temporal bone tissues. The aim of this study was to investigate the feasibility of utilizing this approach to evaluate the codistribution of more than one molecule of interest in a single tissue section.

Study Design: Retrospective study of proteoglycan codistribution in archival human temporal bone tissues.

Proteomic analysis of formalin-fixed celloidin-embedded whole cochlear and laser microdissected spiral ganglion tissues.

Conclusion: The results of this study demonstrate that proteomic analysis can be successfully performed on formalin-fixed celloidin-embedded (FFCE) archival human cochlear tissues.

Objective: To investigate the feasibility of analyzing protein expression in archival cochlear tissues.

Material And Methods: A new methodology, referred to as Liquid Tissue(TM), was used to extract proteins from human cochlear tissue sections and spiral ganglion tissue isolated by laser microdissection (LMD).

Major arc mitochondrial DNA deletions in cytochrome c oxidase-deficient human cochlear spiral ganglion cells.

Conclusions: This study suggests that cytochrome c oxidase subunit 3 (COX 3) expression is diminished in spiral ganglion cells from individuals with presbycusis. In addition to the mitochondrial DNA (mtDNA) common deletion (CD), other deletions involving the mtDNA major arc contribute to the observed deficit in COX 3 expression.

Objectives: To assess COX 3 deficiency in spiral ganglion cells from individuals with presbycusis and to determine whether deletions other than the CD contribute to this deficiency.

Quantification of the mitochondrial DNA common deletion in presbycusis.

Objectives/hypothesis: This study was conducted to evaluate the association between the mitochondrial DNA (mtDNA) common deletion (CD) level in cochlear tissue and the severity of hearing loss in individuals with presbycusis.

Study Design: Nineteen individuals with presbycusis, ranging from 60 to 87 years of age, who met strict audiometric criteria were compared with four age frequency-matched normal hearing controls ranging from 51 to 76 years of age. Five additional normal hearing individuals, ranging from 9 to 50 years of age, were also studied.

Technical report: laser microdissection of cochlear structures from celloidin embedded human temporal bone tissues and detection of the mitochondrial DNA common deletion using real time PCR.

Laser microdissection (LMD) has been used to isolate groups of cells and single cells from numerous tissues. In this study, we describe a technique for isolating cochlear structures and individual spiral ganglion cells from archival celloidin embedded human temporal bone sections. The specimens isolated are suitable for quantifying the mitochondrial DNA (mtDNA) common deletion (CD) within these tissues using a real time polymerase chain reaction (PCR) assay.

Technical report: immunofluorescence and TUNEL staining of celloidin embedded human temporal bone tissues.

The large archival human temporal bone collections of the world have been fixed in formalin and embedded in celloidin. These treatments have created challenges to the use of contemporary probes, which are routinely used in the evaluation of fresh and frozen tissues, for the analysis of archival temporal bone tissues. Formalin alters the configuration of proteins and can obscure antigens by modifying the epitopes recognized by antibodies.

Detection of mitochondrial DNA deletions in the cochlea and its structural elements from archival human temporal bone tissue.

Large-scale deletions of mitochondrial DNA (mtDNA) have been associated with aging and disease in post-mitotic tissues. These post-mitotic tissues, including skeletal muscle, heart and brain, are heavily dependent on intact functional mitochondria. The cochlear tissues are known to contain an abundance of mitochondria.

Presbycusis: a human temporal bone study of individuals with downward sloping audiometric patterns of hearing loss and review of the literature.

Objective: The purpose of this retrospective case review was to identify patterns of cochlear element degeneration in individuals with presbycusis exhibiting downward sloping audiometric patterns of hearing loss and to correlate these findings with those reported in the literature to clarify conflicting concepts regarding the association between hearing loss and morphologic abnormalities.

Methods: Archival human temporal bones from individuals with presbycusis were selected on the basis of strict audiometric criteria for downward-sloping audiometric thresholds. Twenty-one temporal bones that met these criteria were identified and compared with 10 temporal bones from individuals with normal hearing.

Questioning the relationship between cochlear otosclerosis and sensorineural hearing loss: a quantitative evaluation of cochlear structures in cases of otosclerosis and review of the literature.

Background: The literature provides conflicting information regarding the prevalence and cause of sensorineural hearing loss (HL) in individuals with otosclerosis.

Objective: The purpose of this study was to further evaluate the association between involvement of the cochlear endosteal layer with otosclerosis and sensorineural HL.

Study Design: Retrospective case review.

Presbycusis: a human temporal bone study of individuals with flat audiometric patterns of hearing loss using a new method to quantify stria vascularis volume.

Objective: The purpose of this study was to determine the prevalence of stria vascularis atrophy in individuals with presbycusis and flat audiometric patterns of hearing loss. Individuals with presbycusis have historically been categorized by the shape of their audiograms, and flat audiometric thresholds have been reported to be associated with atrophy of the stria vascularis. Stria vascularis volume was not measured in these studies.