Animal Model for Persistent Tympanic Membrane Perforations

1993 ◽  
Vol 102 (6) ◽  
pp. 467-472 ◽  
Author(s):  
Odd Spandow ◽  
Sten Hellström
Keyword(s):  
Animal Model ◽  
Connective Tissue ◽  
Light Microscopy ◽  
Tympanic Membrane ◽  
Healing Rate ◽  
Epidermal Layer ◽  
Tissue Layer ◽  
Connective Tissue Layer ◽  
Once Daily ◽  
Tympanic Membrane Perforations

Topically applied hydrocortisone was used to develop an animal model for persistent tympanic membrane (TM) perforations. Hydrocortisone suspension was applied on the margins of TM perforations of standardized size in rats once daily for 10 days. The healing patterns of the TMs were mapped weekly and, when the perforations were about to close, daily. After 50 days, all hydrocortisone-treated perforations were open, whereas the controls closed within 9 to 12 days. At 3 months, when one third of the perforations still were open, the TMs were studied by otomicroscopy and light microscopy. All TMs were thickened and covered by keratin and wax. The thickened epidermal layer at the border of the TM perforations that remained open also draped the surface of the perforation facing the middle ear cavity. The thickened connective tissue layer contained abundant fibroblasts with their axes of length oriented at random. Both application of 1.4% hyaluronan and wounding of the perforation border enhanced the healing rate of the hydrocortisone-induced chronic TM perforation.

Histological considerations of the cleavage plane for preservation of facial and cochlear nerve functions in vestibular schwannoma surgery

2009 ◽  
Vol 110 (4) ◽  
pp. 648-655 ◽  
Author(s):  
Tomio Sasaki ◽  
Tadahisa Shono ◽  
Kimiaki Hashiguchi ◽  
Fumiaki Yoshida ◽  
Satoshi O. Suzuki
Keyword(s):  
Connective Tissue ◽  
Basic Protein ◽  
Cleavage Plane ◽  
Nerve Fibers ◽  
Vestibular Nerve ◽  
Cochlear Nerve ◽  
Tissue Layer ◽  
Connective Tissue Layer ◽  
Tumor Capsule ◽  
Tumor Parenchyma

Object The authors analyzed the tumor capsule and the tumor–nerve interface in vestibular schwannomas (VSs) to define the ideal cleavage plane for maximal tumor removal with preservation of facial and cochlear nerve functions. Methods Surgical specimens from 21 unilateral VSs were studied using classical H & E, Masson trichrome, and immunohistochemical staining against myelin basic protein. Results The authors observed a continuous thin connective tissue layer enveloping the surfaces of the tumors. Some nerve fibers, which were immunopositive to myelin basic protein and considered to be remnants of vestibular nerve fibers, were also identified widely beneath the connective tissue layer. These findings indicated that the socalled “tumor capsule” in VSs is the residual vestibular nerve tissue itself, consisting of the perineurium and underlying nerve fibers. There was no structure bordering the tumor parenchyma and the vestibular nerve fibers. In specimens of tumors removed en bloc with the cochlear nerves, the authors found that the connective tissue layer, corresponding to the perineurium of the cochlear nerve, clearly bordered the nerve fibers and tumor tissue. Conclusions Based on these histological observations, complete tumor resection can be achieved by removal of both tumor parenchyma and tumor capsule when a clear border between the tumor capsule and facial or cochlear nerve fibers can be identified intraoperatively. Conversely, when a severe adhesion between the tumor and facial or cochlear nerve fibers is observed, dissection of the vestibular nerve–tumor interface (the subcapsular or subperineurial dissection) is recommended for preservation of the functions of these cranial nerves.

Spontaneous healing of traumatic tympanic membrane perforations in man: A century of experience

1992 ◽  
Vol 106 (12) ◽  
pp. 1037-1050 ◽  
Author(s):  
Søren Kristensen
Keyword(s):  
Tympanic Membrane ◽  
Healing Rate ◽  
Reference Value ◽  
Spontaneous Healing ◽  
Clinical Value ◽  
Post Injury ◽  
Tympanic Membrane Perforations ◽  
Pressure Changes ◽  
Perforated Tympanic Membrane

AbstractWidespread controversy exists concerning the treatment of traumatic tympanic membrane perforations. To elucidate the issue, a reference value for the rate of spontaneous tympanic membrane closure in man, to which the healing rates following different techniques of early surgical repair should be compared, was established on the basis of a review of more than 500 texts covering a century's literature on the traumatically perforated tympanic membrane. The spontaneous healing rate appeared to be close to 80 (78.7 per cent) in 760 evaluable cases of traumatic tympanic membrane perforations of all sorts diagnosed within 14 days post injury. A relative, causal-related variation of spontaneous healing could be demonstrated, and a pathogenetic classification of direct traumatic tympanic membrane perforations into ruptures induced by air-pressure changes, heat or corrosives, solids, and water pressures, is of proved clinical value and may have medico-legal validity. There is an obvious need for clinically controlled studies on the spontaneous healing of all kinds of traumatic perforations of the tympanic membrane in humans, and important elements in the design of future studies are advocated.

scholarly journals Effect of Basic Fibroblast Growth Factor on Perforated Chinchilla Tympanic Membranes

1997 ◽  
Vol 76 (8) ◽  
pp. 559-564 ◽  
Author(s):  
Norman R. Friedman ◽  
Charles G. Wright ◽  
Karen S. Pawlowski ◽  
William L. Meyerhoff
Keyword(s):  
Growth Factor ◽  
Connective Tissue ◽  
Tympanic Membrane ◽  
Fibroblast Growth Factor ◽  
Basic Fibroblast Growth Factor ◽  
Healing Process ◽  
Fibroblast Growth ◽  
Short Term ◽  
Tympanic Membrane Perforations ◽  
Perforated Tympanic Membrane

Basic fibroblast growth factor (bFGF) is a polypeptide mitogen which stimulates proliferation of epidermal and connective tissue cells. When applied to tympanic membrane perforations it has been reported to enhance healing and produce connective tissue hyperplasia. Previous work with animal models has shown that hyperplastic alterations of the tympanic membrane play an essential role in cholesteatoma development. This study was designed to further investigate the hyperplastic effects of bFGF and to determine if it might induce cholesteatoma formation during the healing process. Ten chinchillas received bilateral tympanic membrane perforations. In each animal, three doses of bFGF (400 nanograms per dose) were applied to the perforated tympanic membrane on one side; the opposite (control) ear received saline alone. The animals were terminated at either two or four weeks and studied histologically. Although the dosage and administration schedule used were consistent with previous studies utilizing other rodent species, there was little evidence that bFGF affected tympanic membrane healing in chinchillas. In both control and bFGF-treated ears, dense connective tissue occupied the lamina propria of the tympanic membrane, providing an effective barrier against ingrowth of skin toward the middle ear. No cholesteatomas developed in any animals included in the study. The results of this work indicate that the risk of cholesteatoma formation following administration of bFGF is minimal when it is applied short-term to acute perforations.

Quantitative Ultrasound Imaging of Healthy and Reconstructed Cleft Lip: A Feasibility Study

2007 ◽  
Vol 44 (3) ◽  
pp. 261-268 ◽  
Author(s):  
Nancy J. M. van Hees ◽  
Johan M. Thijssen ◽  
Rinske W. Huyskens ◽  
Gert Weijers ◽  
Maartje M. Nillesen ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Cleft Lip ◽  
Scar Tissue ◽  
Noninvasive Evaluation ◽  
Central Position ◽  
Tissue Layer ◽  
Loose Connective Tissue ◽  
Connective Tissue Layer ◽  
Array Transducer ◽  
Orbicularis Oris Muscle

Objective: To investigate the feasibility of echographic imaging of healthy and reconstructed cleft lip and to estimate tissue dimensions and normalized echo level. Methods: Echographic images of the upper lip were made on three healthy subjects and two patients using a linear array transducer (7 to 11 MHz bandwidth) and a noncontact gel coupling. Tissue dimensions were measured using calipers. Echo levels were calibrated and were corrected for beam characteristics, gel path, and tissue attenuation using a tissue-mimicking phantom. Results: At the central position of the philtrum, mean thickness (SD) of lip loose connective tissue layer, orbicularis oris muscle, and dense connective layer was 4.0 (0.1) mm, 2.3 (0.7) mm, and 2.2 (0.7) mm, respectively, in healthy lip at rest; and 4.1 (0.9) mm, 3.8 (1.7) mm, and 2.6 (0.6) mm, respectively, in contracted lip. Mean (SD) echo level of muscle and dense connective tissue layer with respect to echo level of lip loose connective tissue layer was −19.3 (0.6) dB and −10.7 (4.0) dB, respectively, in relaxed condition and −20.7 (1.5) dB and −7.7 (2.3) dB, respectively, in contracted state. Color mode echo images were calculated, showing lip tissues in separate colors and highlighting details like discontinuity of the orbicularis oris muscle and presence of scar tissue. Conclusions: Quantitative assessment of thickness and echo level of various lip tissues is feasible after proper echographic equipment calibration. Diagnostic potentials of this method for noninvasive evaluation of cleft lip reconstruction outcome are promising.

A histological and histochemical study of the development of the amnioallantois in the chick, Gallus domesticus

1970 ◽  
Vol 48 (5) ◽  
pp. 1079-1086 ◽  
Author(s):  
T. P. Kenny ◽  
M. A. Gibson
Keyword(s):  
Connective Tissue ◽  
Incubation Period ◽  
Histochemical Study ◽  
Secretory Granules ◽  
Lymphatic Vessels ◽  
Muscle Layer ◽  
Peak Activity ◽  
Tissue Layer ◽  
Connective Tissue Layer ◽  
Period 2

The amnioallantoic membrane is composed of four layers. (1) An inner amnionic epithelium which is a stratified layer during most of the incubation period. This layer stains positively for glycogen, ribonucleic acid, and neutral and acidic lipids and appears to be most active during the 15 to 17 days of incubation period. (2) A muscle layer composed of dorsoventrally and anteroposteriorly directed bands. During the early incubation stages these bands are organized to form the muscle configurations known as "cross-figures." During the later incubation stages, the organization of these muscle layers is disrupted by invasions of connective tissue and fat. (3) A connective tissue layer which includes blood and lymphatic vessels. (4) An outer allantoic epithelium which is rich in secretory granules. These granules include a sulfated mucopolysaccharide component. The activity of the allantoic epithelium increases progressively during the incubation period and is at peak activity at the 17- to 19-day incubation stage. During the final stages of incubation all layers show signs of decreased activity and degeneration.

The accumulation of ferric iron in the guts of some spatangoid echinoderms

1980 ◽  
Vol 60 (3) ◽  
pp. 631-640 ◽  
Author(s):  
J. B. Buchanan ◽  
B. E. Brown ◽  
T. L. Coombs ◽  
B. J. S. Pirie ◽  
J. A. Allen
Keyword(s):  
Connective Tissue ◽  
Ferric Iron ◽  
Dry Weight ◽  
Iron Deposit ◽  
Tissue Layer ◽  
Intestinal Tissue ◽  
Connective Tissue Layer ◽  
Ferrous Salt ◽  
Ferric Phosphate ◽  
Reducing Conditions

The connective tissue layer of the large intestines of Brissopsis and Echinocardium spp. is shown to contain a massive quantity of ferric iron in the form of ferric phosphate. The ferric phosphate is present as a granular extracellular deposit. In large mature specimens of Brissopsis, the weight of iron present may account for almost 30% of the dry weight of large intestinal tissue. The iron deposit appears to be cumulative with age. It is speculated that the deposit is derived from oxidative deposition of a soluble ferrous salt ingested in reducing conditions.

Cholinergic Motor Control of Sea Urchin Tube Feet: Evidence for Chemical Transmission without Synapses

1980 ◽  
Vol 88 (1) ◽  
pp. 281-292
Author(s):  
E. FLOREY ◽  
M. A. CAHILL
Keyword(s):  
Electrical Stimulation ◽  
Connective Tissue ◽  
Outer Surface ◽  
Muscle Fibres ◽  
Nerve Terminals ◽  
Tissue Layer ◽  
Connective Tissue Layer ◽  
Electrical Stimuli ◽  
Tube Feet ◽  
Chemical Transmission

Isolated tube feet of Strongylocentrotus franciscanus contract briefly when the outer epithelium is touched. Similar twitch-like contractions can be induced by electrical stimulation of the outer surface of the tube foot. These responses appear to be chemically mediated. The following evidence indicates that the transmitter substance may be acetylcholine (ACh): ACh causes muscle contraction. This effect and that of electrical stimuli is potentiated by anticholinesterase agents and is antagonized by cholinergic blocking agents. Anaesthesia with chloralhydrate or chloretone abolishes responsiveness to mechanical or electrical stimulation but not to ACh. Desensitization with carbachol prevents responses to ACh and to mechanical or electrical stimulation. There are no neuromuscular synapses and no axons can be detected which cross the connective tissue layer which separates the muscle fibres from the subepithelial nerve plexus. The latter is known to contain conspicuous amounts of ACh; nerve terminals containing clear vesicles invest the outer surface of the connective tissue layer. All evidence indicates that chemical transmission involves diffusion of ACh (released from activated nerve terminals) across this connective tissue layer which is around 5 μm thick in fully extended tube feet but may have a thickness of 20 or even 25 μm in less extended ones. Calculations based on equations describing transmitter diffusion prove the feasibility of such a mechanism. Note:

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