Involvement of Round and Oval Windows in the Vestibular Response to Pressure Changes in the Middle Ear of Guinea Pigs

Acute middle ear (ME) and inner ear changes following brief unilateral phasic ME pressure changes (up to ± 6000/mm H2O) were studied in the guinea pig. Middle ear findings included perforation of the tympanic membrane, serous and serosanguinous exudate and hemorrhage of tympanic membrane and periosteal vessels. Changes were related to magnitude of applied pressure. Perforation and hemorrhage were more commonly seen with negative rather than positive pressure. Air bubbles behind the round window were seen with positive pressures. Occasional distortion, but never perforation of the round window, was noted. Hemorrhage of the scala tympani was observed with both positive and negative pressures; scala vestibuli hemorrhage was found with negative ME pressure. In some instances pressure direction and magnitude related changes were seen in the contralateral ear.

Download Full-text

Effect of topically applied povidone-iodine on transient evoked otoacoustic emissions in guinea pigs

The Journal of Laryngology & Otology ◽

10.1258/002221503322334512 ◽

2003 ◽

Vol 117 (9) ◽

pp. 700-703 ◽

Cited By ~ 5

Author(s):

Recep Yagiz ◽

Abdullah Tas ◽

Cem Uzun ◽

Mustafa Kemal Adali ◽

Muhsin Koten ◽

...

Keyword(s):

Middle Ear ◽

Guinea Pigs ◽

Otoacoustic Emissions ◽

Povidone Iodine ◽

Positive Control ◽

Middle Ear Surgery ◽

Iodine Solution ◽

Before And After ◽

Transiently Evoked Otoacoustic Emissions ◽

Povidone Iodine Solution

The possible cochlear toxicity of topically applied povidone-iodine solution was investigated in guinea pigs by measuring transiently evoked otoacoustic emissions (TEOAEs). Seven adult pigmented guinea pigs (14 ears) with a normal acoustic pinna reflex were used. After the baseline TEOAE measurements, 0.1mL of povidone-iodine solution was applied transtympanically into the middle ear in the study group. Saline solution and gentamicin were used as negative and positive control, respectively. TEOAE measurements were repeated on the 10th day, and four weeks after the first application. Tympanometric measurements were also carried out for both ears of all animals at the end of the study. Responses in all ears, which had povidone-iodine applied to them, disappeared in a way similar to those recorded in gentamicin-treated ears. Tympanometric measurements at the end of the study showed ’type A’ tympanograms in all ears of all animals. The present study showed that povidone-iodine could have a cochleotoxic effect in guinea pigs. A study in humans with TEOAE before and after middle-ear surgery, where povidone-iodine can reach into the middle-ear cavity, may be useful for evaluating this result for clinical practice.

Download Full-text

Study of Toynbee Phenomenon by Combined Intranasopharyngeal and Tympanometric Measurements

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348948809700220 ◽

1988 ◽

Vol 97 (2) ◽

pp. 199-206 ◽

Cited By ~ 9

Author(s):

Yehuda Finkelstein ◽

Yuval Zohar ◽

Yoav P. Talmi ◽

Nelu Laurian

Keyword(s):

Middle Ear ◽

Negative Pressure ◽

Pressure Change ◽

Positive Pressure ◽

New Information ◽

Pressure Changes ◽

Rapid Pressure

The Toynbee maneuver, swallowing when the nose is obstructed, leads in most cases to pressure changes in one or both middle ears, resulting in a sensation of fullness. Since first described, many varying and contradictory comments have been reported in the literature concerning the type and amount of pressure changes both in the nasopharynx and in the middle ear. In our study, the pressure changes were determined by catheters placed into the nasopharynx and repeated tympanometric measurements. New information concerning the rapid pressure variations in the nasopharynx and middle ear during deglutition with an obstructed nose was obtained. Typical individual nasopharyngeal pressure change patterns were recorded, ranging from a maximal positive pressure of + 450 to a negative pressure as low as −320 mm H2O.

Download Full-text

Volume receptors in guinea pig labyrinth: relevance with respect to ADH and Na control

AJP Renal Physiology ◽

10.1152/ajprenal.1989.257.3.f341 ◽

1989 ◽

Vol 257 (3) ◽

pp. F341-F346 ◽

Cited By ~ 3

Author(s):

E. Bartoli ◽

A. Satta ◽

F. Melis ◽

M. A. Caria ◽

W. Masala ◽

...

Keyword(s):

Inner Ear ◽

Guinea Pigs ◽

Control Mechanism ◽

Extracellular Fluid ◽

Urine Osmolality ◽

Neural Pathways ◽

Group Of Seven ◽

Before And After ◽

Pressure Changes ◽

Inner Ear Pressure

We tested the hypothesis that changes in extracellular fluid volume are reflected by pressure changes within structures of the inner ear and that through neural pathways, a control mechanism exerts an influence on antidiuretic hormone (ADH) release and Na excretion. The study was performed on 35 guinea pigs. In protocol 1, 13 animals were studied before and after decompression of the inner ear by bilateral fluid withdrawal in an experimental setting of sustained isotonic expansion that kept the osmoreceptor partially activated and the intrathoracic volume receptors suppressed. A group of six sham-operated animals served as control. In protocol 2, nine animals were studied before and after a unilateral rise in their inner ear pressure during slightly hypertonic low-rate infusions that kept the osmoreceptor and thoracic volume receptors stimulated. A group of seven sham-operated guinea pigs served as controls. Decompression of the inner ear was attended by a rise in plasma ADH from 11.9 +/- 2.4 to 29.1 +/- 6.9 pg/ml, in urine osmolality (Uosmol) from 470 +/- 48 to 712 +/- 46 mosmol/kg (P less than 0.001), and a fall in urine flow rate (V) from 184 +/- 47 to 71 +/- 11 microliters/min (P less than 0.01), whereas plasma Na (PNa) and osmolality (Posmol) did not change. During inner ear hypertension, plasma ADH fell from 25.6 +/- 3.9 to 18.4 +/- 3.1, Uosmol from 829 +/- 58 to 627 +/- 43 (P less than 0.001), and V rose from 51 +/- 11 to 130 +/- 23 (P less than 0.001), whereas glomerular filtration rate, PNa, and Posmol did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Download Full-text

The Response to Human rIL-1, rIL-2, and rTNF in the Middle Ear of Guinea Pigs

The Laryngoscope ◽

10.1288/00005537-199103000-00008 ◽

1991 ◽

Vol 101 (3) ◽

pp. 271???275 ◽

Cited By ~ 28

Author(s):

Antonino Catanzaro ◽

Allen Ryan ◽

Sharon Batcher ◽

Stephen I. Wasserman

Keyword(s):

Middle Ear ◽

Guinea Pigs

Download Full-text

Histopathological Effects of Boric Acid Solution on Middle Ear Mucosa in Guinea Pigs

Eurasian Journal of Medical Investigation ◽

10.14744/ejmi.2021.49333 ◽

2021 ◽

Author(s):

Ahmet Yukkaldiran

Keyword(s):

Acid Solution ◽

Boric Acid ◽

Middle Ear ◽

Guinea Pigs ◽

Boric Acid Solution ◽

Middle Ear Mucosa ◽

Histopathological Effects

Download Full-text

Chronic exposure to ozone causes tolerance to airway hyperresponsiveness in guinea pigs: lack of SOD role

Journal of Applied Physiology ◽

10.1152/jappl.1998.84.5.1749 ◽

1998 ◽

Vol 84 (5) ◽

pp. 1749-1755 ◽

Cited By ~ 6

Author(s):

Mario H. Vargas ◽

Laura Romero ◽

Bettina Sommer ◽

Pedro Zamudio ◽

Pascal Gustin ◽

...

Keyword(s):

Guinea Pigs ◽

Airway Hyperresponsiveness ◽

Chronic Exposure ◽

Neutral Endopeptidase ◽

Respiratory Effects ◽

Functional Changes ◽

Independent Mechanism ◽

Increased Sensitivity ◽

Pressure Changes

Tolerance to respiratory effects of O3 has been demonstrated for anatomic and functional changes, but information about tolerance to O3-induced airway hyperresponsiveness (AHR) is scarce. In guinea pigs exposed to air or O3 (0.3 parts/million, 4 h/day, for 1, 3, 6, 12, 24, or 48 days, studied 16–18 h later), pulmonary insufflation pressure changes induced by intravenous substance P (SP, 0.032–3.2 μg/kg) were measured, then the animals were subjected to bronchoalveolar lavage (BAL). Bronchial rings with or without phosphoramidon were also evaluated 3 h after air or a single O3 exposure. O3 caused in vivo AHR (increased sensitivity) to SP after 1, 3, 6, 12, and 24 days of exposure compared with control. However, after 48 days of exposure, O3 no longer caused AHR. Total cell, macrophage, neutrophil, and eosinophil counts in BAL were increased in most O3-exposed groups. When data from all animals were pooled, we found a highly significant correlation between degree of airway responsiveness and total cells ( r = 0.55), macrophages ( r = 0.54), neutrophils ( r = 0.47), and eosinophils ( r = 0.53), suggesting that airway inflammation is involved in development of AHR to SP. Superoxide dismutase (SOD) levels in BAL fluids were increased ( P < 0.05) after 1, 3, 6, and 12 days of O3 exposure and returned to basal levels after 24 and 48 days of exposure. O3 failed to induce hyperresponsiveness to SP in bronchial rings, and phosphoramidon increased responses to SP in air- and O3-exposed groups, suggesting that neutral endopeptidase inactivation was not involved in O3-induced AHR to SP in vivo. We conclude that chronic exposure to 0.3 ppm O3, a concentration found in highly polluted cities, resulted in tolerance to AHR to SP in guinea pigs by an SOD-independent mechanism.

Download Full-text