About
Investigator:
Fred H. Linthicum, Jr., M.D.
Research Summary:
The mission of the Temporal Bone Laboratory of the Cell Biology and Genetics Division is to investigate the causes of hearing and balance disorders by microscopically examining the middle and inner ear structures, contained in the temporal bone, of deceased individuals. The development of treatment for the various ear disturbances depends on learning their causes.
Examination of temporal bones has been made possible by a pledge program begun in 1946 when patients of the House Clinic, with various types of ear problems, are asked to pledge their temporal bones for future research. To date, over 4,000 individuals have signed temporal bone pledges and, over the 60 years of the program, more than 800 pairs of bones have been processed and examined. The preparation of the each bone for microscopic evaluation requires almost a year because of the slow decalcification other techniques needed to make the middle and inner ear structures suitable for microscopic analysis.
The clinical history, including hearing and balance testing, when indicated, and the microscopic analysis findings are recorded in a computer data base that also contains microscopic images of pertinent findings. The data base makes possible searches for various combinations of symptoms and microscopic findings that help define a specific disease process. A large number of specimens are needed when a specific disease is evaluated for over a lifetime patients develop several other abnormalities that can overshadow more subtle changes of an individual abnormality, but by examining several bones with similar clinical findings, a definite conclusion may be reached.
In the last few years, more advanced analytical methods are being employed in the analysis of the temporal bones, both newly acquired and those processed in the past. These techniques include: 1. Immunohistochemical analysis that allows us to identify specific substances within cells. 2. DNA extraction that helps identify hereditary ear abnormalities. 3. Computer aided three dimensional reconstruction of microscopic structure that helps us to better conceptualize the configuration of formations too small to see normally. 4. Proteomic analysis that will allow us to determine the various proteins involved in cell structure and function.
Over 250 scientific papers and book chapters have been written using material from the temporal bone laboratory. Findings from the laboratory have been instrumental in establishing medical treatment for advanced otosclerosis, and modifying surgical approaches of cochlear implants, endolymphatic sacs, neurofibromatosis 2, and the vestibular nerve.