Everbach, E. Carr

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Swarthmore CollegeWorksEngineering Faculty Works Engineering6-1-1991Report Of The 12th F.V. Hunt Postdoctoral Fellow(1989-1990)E. Carr EverbachSwarthmore College, ceverba1@swarthmore.eduFollow this and additional works at: http://works.swarthmore.edu/fac-engineeringPart of the Engineering CommonsThis Article is brought to you for free and open access by the Engineering at Works. It has been accepted for inclusion in Engineering Faculty Works byan authorized administrator of Works. For more information, please contact myworks@swarthmore.edu.Recommended CitationE. Carr Everbach. (1991). "Report Of The 12th F.V. Hunt Postdoctoral Fellow (1989-1990)". Journal Of The Acoustical Society OfAmerica. Volume 89, Issue 6. 3011-3012.http://works.swarthmore.edu/fac-engineering/45ware was presented in a previous article by the author. 5 These are to be used also in teaching vibration and sound. •Announcer of the American Association of Physics Teachers, 20(4), 58-60 (1990), Session CB•Instructional Uses of Video. 2Announcer ofthe American Association of Physics Teachers, 20(4), 107- 108 (1990), Session GGmSymposium on National Interactive Media Pro- ject. 3j. Acoust. Soc. Am. Suppl. 1 88, S40-S41 (1990), Session 3ED--Educa- tion in Acoustics: Videotapes for Teaching Acoustics. 4T. D. Rossing, Teaching the Science of Sound (Rossing, De Kalb, IL, 1982); write to T. Rossing, Physics Department, Northern Illinois Univer- sity, De Kalb, IL 60115. 5F. B. Stumpf, J. Acoust. Soc. Am. 77, 1989-1990 (1985). Report of the 12th F. V. Hunt Postdoctoral Fellow (1989-1990) [43.05.Pc] Erich Carr Everbach Department of Engineer/ng, Swarthmore Co//ege, Swarthmore, Pennsy/vania 19081 (Received 18 December 1990; accepted for publication 6 February 1991 ) The main goal of my research at the University of Roch- ester during my year as Hunt Fellow was to determine the physical mechanisms of kidney and gallstone destruction by acoustic lithotripsy. I was fortunate in being able to collabo- rate with members of the Rochester Center for Biomedical Ultrasound such as Edwin Carstensen, Sally Child, Sheryl Gracewski, Stephen Burns, and Nimish Vakil. Dr. Vakil, a gastroenterologist and clinical gallstone lithotripsy expert, was instrumental inallowing me to have access to two clini- cal lithotripters in regular use at the Strong Memorial Hos- pital. In early studies of the destruction of model stone mate- rials in the clinical lithotropters, we began to realize the importance of the material properties of the stone in deter- mining the success of lithotropsy. A paper I was submitted describing the importance of careful preparation of sample materials and the influence of stone properties on the mecha- nisms of destruction. These findings led us to seek experts who could help us determine the mechanical properties of gallstones. We were fortunate to enlist the aid of a materials scientist (Stephen Burns) and a geologist an d specialist on crystal structure (Asish Basu). After an extensive experi- mental study of the microhardness of gallstones, we submit- ted another paper 2 detailing some of our measurements. Much work is still ongoing to determine other properties such as the fracture toughness and dynamic critical fracture stress of gallstones; during 1989-1990 much of the ground- work (including construction of apparatus) was laid. An- other fruitful line of investigation developed when we dis- covered that some of the gallstones we were using for in vitro lithotripsy experiments floated prior to the first shock wave application and sank afterward. A paper 3describing the gas content of human gallstones and its implications in favoring one mechanism over another in acoustic lithotripsy was sub- mitted. During 1989-1990, aspects of the lithotripsy re- search were presented by my colleagues and me at various meetings. 4-11 During my year at Rochester, I designed and built pro- totypes of an inexpensive wide-bandwidth hydrophone for lithotripsy research. The resulting instrument repregents a significant improvement over existing hydrophones com- monly used by researchers to determine the acoustic field of a lithotripter. Currently, I am still refining the design of the piezoelectric opolymer that is the hydrophone's active ele- ment, and expect to submit soon for publication a complete description of the device. The basic design of the hydro- phone was outlined in an abstract and accompanying pre- sentation at the spring 1990 Acoustical Society meeting at Penn State. 12 Although the lithostripsy research was my main focus during my year as Hunt Fellow, I found the research envi- ronment at the University of Rochester so fertile that I par- ticipated in several other projects. I collaborated on an inves- tigation of the properties of echo-contrast agents reported at meetings of cardiologists uch as the American Heart Asso- ciation. 13.14 1 also investigated the color of the stomach lin- ing as an indicator of pathology, 15 worked on improving the design of a device for removing bubbles from blood acousti- cally, and did preliminary experiments to determine the role of acoustic cavitation in the ablation of arterial plaque. Per- haps most important, however, was the long-term collabora- tion that I have established with the researchers atthe Uni- versity of Rochester. I accepted a nontenure appointment as an Adjunct Professor of Electrical Engineering at Rochester to allow me to spend my summers and sabbatical years from Swarthmore College at the University of Rochester. I look forward to years of productive research on topics of biomedi- cal acoustics. None of this would have been possible without the help of the F. V. Hunt Fellowship, and I remain most grateful for the opportunities it afforded me. IN. Vakil, S. Gracewski, and E. Carr Everbach, "Relationship of model stone properties to fragmentation mechanisms during lithotripsy," J. Lithotripsy Stone Disease, to be published ( 1991 ). 2S. M. Gracewski, N. Vakil, E. Carr Everbach, M. E. Davis, and S. J. Burns, "Microhardness properties of human gallstones and synthetic stones," submitted to J. Biomech. Eng. October (1990). 3N. Vakil and E. Carr Everbach, "Gas in gallstones: quantitative determi- nations and effects on fragmentation by shock waves," submitted to Gas- troenterology (1990). 4S. J. Burns, S. M. Gracewski, E. C. Everbach, N. Vakil, and A. R. Basu, "Dynamic failure mechanisms in gallstones using lithotripsy," Intl. Smnr. Dynam. Failure Materials, Paper presented at the ISDFM meeting in Vi- enna, Austria ( 1991 ). 5S. J. Burns, S. M. Gracewski, E. C. Everbach, N. Vakil, and A. R. Basu, "Dynamic failure mechanisms in gallstones using lithotripsy," Intl. Smnr. Dynam. Failure Materials, Paper presented at the ISDFM meeting in Vi- enna, Austria ( 1991 ). 6S. M. Gracewski, N. Vakil, E. Carr Everbach, and S. J. Burns, "Micro- hardness properties of gallstones and synthetic stones," Int. Conf. IEEE Eng. Med. Biol. Soc., Paper presented at the 12th annual meeting of the IEEE in Philadelphia, PA (1990). 7E. Carr Everbach, S. M. Gracewski, and N. Vakil, "Properties of gall- stones and their relationship to destruction mechanisms in acoustic litho- tripsy," J. Acoust. Soc. Am. Suppl. 1 87, S 141 (1990). BE. Carr Everbach, S. M. Gracewski, and N. Vakil, "Mechanisms of stone destruction by shock waves," Gastroenterology 98 (5), A574 (1990). 9S. M. Gracewski, S. J. Burns, E." ....... u•u and N. x;•w• ,,•,•,• mechanical properties of gallstones and their relationship to lithotripsy," Gastroenterology 98 ( 5 ), A590 (1990). •øN. Vakil and E. Carr Everbach, "Quantitative determinations of gas in human gallstones," Gastroenterology 98 (5), A641 (1990). •lR. S. Meltzer, K. Q. Schwarz, J. G. Mottley, and E. Carr Everbach, "The 3011 J. Acoust. Soc. Am. 89(6), June 1991 0001-4966/91/063011-02500.80 © 1991 Acoust. Soc. Am; Forum 3011  Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP:  130.58.65.20 On: Wed, 14 Jan 2015 16:32:44potential of therapeutic cardiac ultrasound," Am. Coll. Cardiol., Paper presented at March 1990 meeting in Atlanta, GA. •2E. Carr Everbach, "An inexpensive wide-bandwidth hydrophone for lith- otripsy research," J. Acoust. Soc. Am. Suppl. 1 87, S 128 (1990). •3R. S. Meltzer, S. Gottlieb, J. Mottley, A. Ernst, E. C. Everbach, R. Schlief, K. Q. Schwarz, and J. R. Shapiro, "Pressure sensitivity of sonicated albu- min and saccharide contrast agents," Feinstein Meeting on Echocontrast, Chicago, IL (1990). •4j. Mottley, E. C. Everbach, K. Q. Schwarz, R. Schlief, and R. S. Meltzer, "Decay of ultrasound integrated backscatter from a saccharide contrast agent is accelerated by increased pressure," American Heart Association, Paper presented at AHA meeting in Dallas, TX (1990). •SN. Vakil and E. C. Everbach, "Color of gastrointestinal tissues and its use in diagnosis," Advances in Gastroenterology (book chapter), London (1991). Report of the 1 l th F. V. Hunt Postdoctoral Fellowship (1988-1989) [43.05.Pc] Elizabeth C. Oesterle Department of Oto/aryngo/ogy, Un/vers/ty of Wash/ngton, Seat#e, Wash/ngton 98195 (Received 5 October 1990; accepted for publication 6 February 1991 ) Previously, during my Ph.D. thesis, research with Dr. Peter Dallos (Northwestern University, Evanston, IL), I recorded intracellularly from cells in the organ of Corti and attempted to determine the origins of sound-induced poten- tial changes recordable in the supporting cells of the organ. Findings demonstrated the existence of potentials that ap- peared to emanate from the supporting cells themselves and were reminiscent of slow electrical potential changes that occur in central nervous system (CNS) glial cells [E. C. Oesterle and P. Dallos, "Intracellular recordings from sup- porting cells in the guinea pig cochlea: AC potentials," J. Acoust. Soc. Am. 86, 1013-1032 (1989); E. C. Oesterle and P. Dallos, "Intracellular recordings from supporting cells in the guinea pig cochlea: DC potentials," J. Neurophysiology 64, 617-636 (1990) ]. The results were consistent with the hypothesis that some types of inner-ear supporting cells may function similarly to the glial cells of the CNS-•operating to maintain the homeostatic environment surrounding the hair cells and eighth-nerve ndings by participating in the uptake and inactivation of chemical transmitters from the extracel- lular spaces and/or buffering levels of extracellular ions. The F. V. Hunt postdoctoral fellowship gave me the opportunity to continue research in this area under the su- pervision of Dr. Edwin W. Rubel (Dept. of Otolaryngology, University of Washington, Seattle, WA). Research explor- ing possible similarities between inner-ear supporting cells and the better studied neuroglia was conducted during the fellowship period, June 1988 to August 1989. More specifi- cally, the hypoth•esis that proteins known to be present in CNS glia are also present in inner-ear supporting cells was investigated. Antibody labeling techniques were used to look for the existence of two classes of intermediate filaments in inner- ear supporting cells which are uniquely associated with glial cells in the CNS. Vimentin and glial fibrillary acidic protein (GFAP) are intermediate filament proteins present normal- ly in many types of neuroglia. During glial reactivity (when glial cells form scars in response to neural or sensory cell damage) dramatic increases in intermediate filament con- tent are observed, and increased GFAP and vimentin im- munostaining are seen. In response to photoreceptor degen- eration, retinal Muller cells express GFAP immunoreactivity even though they do not express this pro- tein normally. Since auditory support cells form phalangeal scars in response to hair-cell degeneration, it appeared plau- sible that GFAP and vimentin immunoreactivity might be expressed in auditory support cells in response to hair-cell injury. Studies of GFAP and vimentin expression in normal and experimentally damaged mammalian cochleas were completed. Findings were presented at several meetings [Oesterle et al., "Distribution of vimentin in the guinea-pig cochlea," Soc. Neurosci. Abstr. 14, 488 ( 1988); Y. Raphael and E. C. Oesterle, "The distribution of intermediate fila- ments in the organ of Corti," Assoc. Res. Otolaryngol. Abstr. 12, 111 (1989) ], and a paper was published [Oesterle et al., "Intermediate filaments in the inner ear of normal and experimentally damaged guinea pigs," Hear. Res. 47, 1-16 (1990) ]. Findings regarding the normal organ of Corti in adoles- cent and adult guinea pigs indicate that vimentin is present in two types of supporting cells, Deiters' cells and inner pil- lar cells. Our observations also suggest he existence of a differential distribution of vimentin immunoreactivity among Deiters' cells in the mature guinea-pig organ of Corti and raise questions regarding the possible existence of sub- classes of Deiters' cells. GFAP immunoreactivity was not detected in any supporting-cell type in the normal organ of Corti. Cochlear hair cells were unlabeled for either GFAP or vimentin. The expression of vimentin and GFAP in end or- gans, where hair-cell degeneration was experimentally in- duced, was not observed in phalangeal scars replacing lost hair cells. These findings concerning the absence (or pres- ence) of GFAP and vimentin in the auditory support cells suggest that auditory support cells do not use the same cyto- skeletal proteins as CNS neuroglia, thereby contributing to an understanding of the roles inner-ear support cells play in end-organ functioning. The F. V. Hunt fellowship provided the opportunity to conduct this research, and for this I am most grateful. In answering the experimental question, I acquired expertise with anatomical and immunocytochemical techniques and was exposed to a new research environment. I am presently applying the techniques learned during the fellowship year in my current studies of regeneration in the inner ear. I would like to offer a big "thank you" to the Hunt family and the Acoustical Society of America for making this possible. 3012 J. Acoust. Soc. Am. 89(6), June 1991 0001-4966/91/063012-01500.80 ¸ 1991 Acoust. Soc. Am; Forum 3012  Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP:  130.58.65.20 On: Wed, 14 Jan 2015 16:32:44

Report Of The 12th F.V. Hunt Postdoctoral Fellow (1989-1990)

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Report Of The 12th F.V. Hunt Postdoctoral Fellow (1989-1990)

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