Current methodologies for characterization of tympanic membranes (TMs) have some limitations. They: are qualitative rather than quantitative, consist of single point mobility measurements, or only include one-dimensional deformation measurements. Furthermore, none of the current clinical tools for diagnosis of hearing losses have the capability to measure the shape of TM, which is very useful for anatomical or pathological investigations. The multi-wavelength lensless digital holography system (MLDHS) reported in this work consists of laser delivery (LD), optical head (OH), and computing platform (CP) subsystems, with capabilities of real-time, non-contact, full-field of view measurements. One version of the LD houses two tunable near-infrared external-cavity diode lasers with central wavelengths of 780.24nm and 779.74nm respectively, an acousto-optic modulator, and a laser-to-fiber mechanism. The output of the LD is delivered to an ultra-fast MEMS-based fiber optic switch and the light beam is directed to the OH, which is arranged to perform imaging and measurements by phase-shifting holography. The second LD version subsystem contains one tunable near-infrared diode laser in the range from 770nm to 789nm, an anamorphic prism pair, an acousto-optic modulator, a half-wave plate, and a fiber coupler assembly. The output of the LD is delivered to the OH directly. The OH is designed by 3D optical ray tracing simulations in which components are rotated at specific angles to overcome reflection issues. A high-resolution digital camera with pixel size of 6.7μm by 6.7μm in the OH is used for image recording at high-rates while the CP acquires and processes images in either time-averaged or double-exposure modes. The choice of working version depends on the requirements of the measurement and the sample under test. MLDHS can obtain shape and one-dimensional deformations along one optical axis (z-axis). In order to recover 3D deformations, assumptions based on elasticity theory are prerequisites for the calculations: (a) the TM is analyzed as a thin shell; (b) shape before and after deformation is considered nearly the same since acoustic pressure typically introduces nanometer scale deformations; and (c) normal vectors remain perpendicular to the deformed mid-plane of the TM. Another part of this Thesis is the design and prototyping of the MLDHS, which translates this holographic platform into a simple and compact holographic instrument for measurements of the visible tympanic-membrane motions in live patients. Therefore, the OH subsystem needs to be light and portable, as it can be mounted on a robotic arm be near the ear canal, while the LD subsystem needs to be stable and safely protected. Preliminary results of acoustically induced 3D deformations and shape measurements by a single instrument that demonstrate the capabilities of the devices developed in this Thesis are presented.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Bibliography: leaves 255-256. / by Thomas Joseph Lynch III. / Ph.D.

Otitis media, which is an upper respiratory tract infection that affect the middle ear, is the second most common disease in childhood, outnumbered in prevalence only by the common cold. Diagnosis of middle ear inflammation is often performed in the primary healthcare where the normal procedure involves anamnesis and physical examination of the tympanic membranes (TM) of the patient, usually be means of otoscopy. The general aim of this thesis was to develop optical methods that enable quantification of TM characteristics associated with otitis media. Diffuse reflectance spectroscopy was applied to quantify TM erythema using previously suggested erythema detection algorithms. Healthy TM:s were significantly distinguished from TM:s with induced erythema (p < 0.01) and from TM:s in ears with mucous middle ear effusion (p < 0.05). A new technique for surface shape assessment based on an on-axis dual fibre array incorporated in an otoscope was developed and evaluated in ear models and on tympanic membranes from harvested temporal bones. The technique utilises the combined effects of source-detector fibre separation and fibre-to-sample distance on the detected light intensity. Optical phantoms, both polyacetal plastic solids and latex membranes, were utilised to demonstrate the ability of the surface shape assessment technique to differentiate between convex and concave surfaces – as a bulging tympanic membrane is typically associated with acute otitis media whereas a retracted eardrum is associated with otitis media with effusion. Monte Carlo simulations of the surface shape data were performed in order to validate the experimental results with a theoretical model that are consistent with light transport theory. Retracted and bulging tympanic membranes from harvested temporal bones could be separated with a single measurement, given that variations in measurement distance were accounted for and that measurement from normally positioned tympanic membranes were used for signal normalization. In conclusion, the studies implicate that for individual otitis diagnosis, the hyperaemic tympanic membrane was separated from the healthy by application of erythema indices using diffuse reflectance spectroscopy. Moreover, bulging and retracted positions of the tympanic membrane were separable by means of the source-detector intensity matrix. For further clinical studies it is reasonable to assume that data from both methods are needed for diagnosis.

The healing of tympanic membrane (TM) perforations is a complex wound healing process including inflammation, migration of keratinocytes and tissue remodelling. Most TM perforations in human heal spontaneously, however some perforations become chronic, and the reason to why is still largely unknown. In cutaneous wound healing plasminogen (plg) has been shown to play an important role. Plg is converted into the protease plasmin regulated by two plasminogen activators (PA), urokinase type PA (uPA) and tissue-type PA (tPA). The aim of the present thesis was to evaluate the role of plg in healing of TM perforations, both in vivo and in vitro. The main objectives were to determine the healing capacity of the TM, the involvement of keratinocytes, fibrin(ogen) and inflammatory cells in the healing process. The studies were performed in plg deficient and uPA deficient mice, with littermate wild type (wt) mice as controls It was shown that myringotomies of the TMs in plg deficient mice still remained open 143 days following a perforation. The wound area was characterized by an abundant recruitment and accumulation of inflammatory cells; mainly macrophages and neutrophils, an arrested keratinocyte migration and a fibrin deposition covering the surface of the TM. The TM perforations in the wt mice all healed within 11 days. Interestingly, the myringotomies of the plg deficient mice could be closed by reconstitution with systemic injections of plg, whereas injections of PBS had no affect on the healing. To characterize mechanisms involved in the development of persistent TM perforations in plg deficient mice after a myringotomy the early inflammatory response during the first 48 hours was studied. The recruitment and accumulation of inflammatory cells in the perforated TMs was found to be similar between the plg deficient and the wt mice. Myringotomized TMs in uPA deficient mice healed similar to perforations of wt controls. Neither did the keratinocyte migration nor the occurrence of inflammatory cells differ between these genotypes. In the in vitro experiments TMs from plg deficient and wt mice, were dissected out, perforated and cultured in absence or surplus of plg. A decrease in perforation size was seen in all groups regardless of genotype or amount of plg in the medium. In conclusion, the present studies show: • Plg is essential for the healing of TM perforations in mice. • The altered healing process after a myringotomy in plg deficient mice involves a disturbed keratinocyte migration, a massive deposition of fibrin and an abundant accumulation of inflammatory cells in the wound area. • Plasminogen deficiency does not alter the early inflammatory response, following a myringotomy. • Deficiency of uPA does not influence the healing of TM perforations. • During in vitro conditions healing of TM perforations is initiated irrespectively of genotype of the explant (plg deficient or wt) or supply of plg. The increased knowledge of the involvement of plg in the healing of TM perforations may open therapeutical possibilities in the treatment of chronic TM perforations in humans.

A prerequisite for a functioning middle ear is an air-filled middle ear cavity. Aeration of the middle ear cavity is controlled by the Eustachian tube. Dysfunction of the Eustachian tube has long been acknowledged as a significant etiological factor in disorders of the middle ear, especially middle ear effusions. Artificial ventilation of the middle ear through the tympanic membrane has been practised for almost two centuries, but with varying degrees of success. In 1954, Armstrong reintroduced the method of inserting a transmyringeal tympanostomy tube into the ear drum. Since that time this ventilatory device has gained wide popularity and several types of tube have been designed. However, an increasing number of clinical reports have shown treatment with tympanostomy tubes to be followed by complications such as tympanosclerosis, atrophy, persistent perforations and cholesteatomas. In the present thesis, experiments were outlined in which the tympanostomy tube - tympanic membrane interaction was studied and in which tympanostomy tubes were also applied in a well-defined type of otitis media. Furthermore, alternative transmyringeal ventilatory procedures such as myringotomies with a delayed healing time were investigated. The results were evaluated with morphological and microbiological methods. Repeated tympanostomy tube insertions in ears of healthy rats caused a remarkable thickening (about 30-fold) of the tympanic membrane of the tubulated quadrants, but even the untouched quadrants were affected. The thickened areas were characterized mainly by an increase in dense connective tissue which also contained sclerotic plaques. The structural changes in the tympanic membrane were still present 3 months after the final ventilation episode. Cleavage of the rat soft palate caused an immediate accumulation of effusion material in the tympanic cavity due to disturbance of Eustachian tube function. The fluid turned purulent within one to two weeks. The microbial flora of the middle ear cavity correlated well with that of the nasopharynx, indicating an ascending infection. Insertion of a tympanostomy tube could prevent the accumulation of effusion material in the meso- and hypotympanon and significantly suppress bacterial growth in the middle ear cavity. Thermal energy-inflicted myringotomies were tested as an alternative method for establishing transmyringeal ventilation. Myringotomies performed either with a CCL-laser or by diathermy showed a delayed healing pattern, most probably due to widespread destruction of the outer keratinized squamous epithelium and damage to the vascular supply. Upon comparison, laser myringotomies appeared more favourable due to their longer closure times, whereas the perforations accomplished by diathermy were often complicated by otorrhea and showed more advanced structural changes. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1985, härtill 6 uppsatser.</p> / digitalisering@umu

No description available.

O efeito do fator de crescimento epitelial e da pentoxifilina, isolados ou em associação, foi avaliado em perfurações subagudas de membranas timpânicas de chinchilas, comparando-se ao grupo controle. O fator de crescimento epitelial auxiliou o processo de cicatrização de perfurações subagudas de membranas timpânicas, o que não se observou com a pentoxifilina. O percentual de cicatrização das perfurações foi de 30,3%, 3,6%, 16,5% e 8,7% nos grupos fator de crescimento epitelial, pentoxifilina, fator de crescimento epitelial com pentoxifilina e controle, respectivamente / The effect of epidermal growth factor and pentoxifylline, in combination or alone, was evaluated in chinchillas with subacute tympanic membrane perforations, and compared with a control group. Epidermal growth factor helped in the healing of subacute tympanic membrane perforations, but the same was not observed for pentoxifylline. The healing rate of perforations was 30.3%, 3.6%, 16.5% and 8.7% for the following groups: epidermal growth factor, pentoxifylline, epidermal growth factor with pentoxifylline and untreated controls, respectively

O efeito do fator de crescimento epitelial e da pentoxifilina, isolados ou em associação, foi avaliado em perfurações subagudas de membranas timpânicas de chinchilas, comparando-se ao grupo controle. O fator de crescimento epitelial auxiliou o processo de cicatrização de perfurações subagudas de membranas timpânicas, o que não se observou com a pentoxifilina. O percentual de cicatrização das perfurações foi de 30,3%, 3,6%, 16,5% e 8,7% nos grupos fator de crescimento epitelial, pentoxifilina, fator de crescimento epitelial com pentoxifilina e controle, respectivamente / The effect of epidermal growth factor and pentoxifylline, in combination or alone, was evaluated in chinchillas with subacute tympanic membrane perforations, and compared with a control group. Epidermal growth factor helped in the healing of subacute tympanic membrane perforations, but the same was not observed for pentoxifylline. The healing rate of perforations was 30.3%, 3.6%, 16.5% and 8.7% for the following groups: epidermal growth factor, pentoxifylline, epidermal growth factor with pentoxifylline and untreated controls, respectively

Plasmin has been suggested to be involved in degradation of extracellular matrix (ECM) and tissue remodeling during a number of physiological and pathological processes. The aims of this thesis were to study the functional roles of plasmin during pathological inflammation in autoimmune and nonautoimmune disease models of rheumatoid arthritis (RA), multiple sclerosis (MS), wound healing and infection. In order to explain the obtained results in our functional studies as well as some previous results on the functional roles of plasmin during different tissue remodeling processes, I propose that there is a functional correlation between absence of plasmin and an inability to activate complement. The role of plasminogen during autoimmune collagen type II-induced arthritis (CIA) was studied first. The data revealed that whereas 83% of wild-type (plg+/+) mice developed CIA, none of the plasminogendeficient (plg-/-) mice got arthritis within a 40-day period. When plg+/+ mice were injected with a mixture of monoclonal antibodies against collagen type II they developed arthritis within a 5-day period, whereas no arthritis could be seen in plg-/- mice, although these mice had normal binding of antibody to the cartilage surface. These data suggest that plasmin plays an essential role in the step between antibody binding and inflammatory cell infiltration during CIA, probably during the step of complement activation. When plg+/+ and plg-/- mice were injected intra-articularly with collagen type II or 0.9% NaCl following CIA induction, plg-/- mice developed typical CIA, but the disease was less severe than in the plg+/+ mice and restricted to the injected joints. Sustained tissue necrosis was found only in the plg-/- mice after the local injection. When the antigen-induced arthritis (AIA) model was used, plg-/- mice developed a much more severe arthritis than the plg+/+ mice. These results indicate that different forms of pathogenesis exist for CIA and AIA, and further emphasize the importance of trauma in the induction of CIA in plg-/- mice. We further investigated the role of plasmin in experimental autoimmune encephalomyelitis (EAE), which is an autoimmune disease model for MS. During a 2-month period, the severity, incidence, mean onset day, mean maximal score and mean accumulative score of EAE were essentially identical in plg-/- and plg+/+ mice of B10.Q background. Histopathological studies revealed similar levels of inflammation and demyelination in plg-/- and plg+/+ mice. These data indicate that plasmin does not play an essential role in the development of EAE. The findings that plasmin is essential for the development of CIA but not needed for the development of EAE suggest that plasmin may play a pivotal role in autoimmune diseases where complement activation is critically involved in the pathogenesis. The role of plasmin was also studied in a tympanic membrane (TM) wound healing model. After TM perforations were performed, the plg+/+ TMs had all healed by day 11, whereas TM healing was completely arrested in plg-/- mice even as late as day 143. Immunohistochemical studies revealed a disturbed inflammation and tissue remodeling pattern in plg-/- mice. These data indicate that plasmin plays a central role in the healing of TM perforations. The involvement of plasminogen in ear infections was also investigated in plg-/- mice. During an 18-week experimental period, spontaneous otitis media (OM) was essentially developed in all of the plg-/- mice, whereas all of the plg+/+ mice kept a normal TM status. Positive bacterial growth was found in 5 out of 6 plg-/- mice, but only in 1 out of 6 plg+/+ mice. Immunohistochemical studies showed an accumulation of inflammatory cells, fibrin and also other extracellular matrix in the middle-ear cavity and the external-ear canal of plg-/- mice. These results show a spontaneous development of OM in plg-/- mice, but not in plg+/+ controls, suggesting that plasmin plays a critical role in the defense mechanisms during ear infections. Taken together, plasmin appears to play essential roles during autoimmune and non-autoimmune diseases in which complement activation is critical in the pathogenesis.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 5 uppsatser.