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This paper presents the autoimmune lesions of the inner ear by using isologous inner ear antigen (IEAg) on the guinea pigs. The purposes of this study were to determine whether the inner ear is an immune response organ and what is the sequelae of the immune processes both on physiological and morphological changes in the inner ear. Animals were systemically sensitized with IEAg in complete Freund's adjuvant and boothed with IEAg in incomplete Freund's adjuvant three times in every 3-4 weeks and then allowed to survive 4-6 weeks. For the ABR measurement, 8 of 28 ears (28.6%) in the experimental group showed threshold enhancement greater than or equal to 10dB before the animal sacrifice and the mean threshold shift of the ABR 8 weeks post immunization and before sacrifice revealed significant difference. Histological specimens were processed for both light and electron microscopic study. In the LM study, it showed endolymphatic hydrops, local thickening of the Reissener's membrane, and spiral ganglion cells lost. In the SEM, disturbance and loss of the cilia of the outer hair cells of the cochlea and the type I and II sensory cells in the crista ampularis can be seen. Also, some otoconia showed numerous malformation.
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PMID:[Experimental autoimmune lesions of the inner ear]. 159 Oct 43

Newborn kittens were treated with the aminoglycoside amikacin to produce a bilateral high frequency cochlear hearing loss. The degree and stability of hearing loss were confirmed by recording auditory brainstem evoked potentials (ABR audiograms). After maturation, cochleotopic frequency representation within primary auditory cortex (AI) was mapped using standard microelectrode recording techniques. The cochlear sensory epithelium was assessed with SEM and the pattern of damage compared with the ABR audiograms and cortical frequency maps. Amikacin treatment resulted in various patterns of haircell damage towards the base of the cochlea. A relatively abrupt transition between damaged and undamaged haircell regions resulted in an ABR audiogram with normal threshold to low frequencies and a high frequency elevation with a steep cut-off slope. In the cortical map, low frequency representation was normal, but anterior areas contained only neurons tuned to a common frequency which corresponded to the frequency-place position of the boundary of the haircell lesion and to the cut-off frequency of the audiogram. A large transitional zone of the cochlear lesion correlated with a gradual cut-off slope to the audiogram and again a remapping of the anterior and normally high frequency area to a common lower frequency. Haircell loss or damage (i.e. disarray of stereocilia) in lower frequency regions of the cochlea correlated with a significant reorganization of the lower frequency bands in the cortical map. We conclude from this study that the pattern of cochleotopic organization of the cortex is dependent on the pattern of activity in the ascending sensory pathway during early stages of development.
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PMID:Correlation of cochlear pathology with auditory brainstem and cortical responses in cats with high frequency hearing loss. 182 32

Coenzyme Q10 (CoQ10) has already been favorably evaluated in the clinical treatment of heart disease. In the otolaryngological field, it has been reported that CoQ10 is effective in promoting recovery from acute sudden deafness. However, the pharmakinetics of CoQ10 in the inner ear is not yet clarified. The present study focuses upon the pharmacokinetics of CoQ10 using guinea pigs with acute sensorineural hearing loss artificially induced by hypoxia conditions. The respiration of the animals was controlled in an artificial respirator while the ABR, ECG and blood pressure were monitored. Repeated hypoxia caused a gradual disappearance of the ABR. After the experiments, the animals were sacrificed and brain and inner ear were examined by histological and histochemical methods as well as by SEM and TEM. The results indicated that CoQ10 is effective in promoting recovery from damage in auditory hairs as well as preventing respiratory metabolic impairment of hair cell due to hypoxia.
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PMID:Pharmacokinetics of coenzyme Q10 in recovery of acute sensorineural hearing loss due to hypoxia. 324 40

Forty-five guinea pigs were randomly divided into 2 groups: 15 in the control group and 30 in the experimental group. All animals were injected immediately with 400 mg/kg kanamycin for 10 days. At the same time, the experimental animals were given orally 10 mg/kg thyroxin every other day 5 times. All animals were decapitated 10 days after administration of drugs and measurement of ABR. Then, the specimens of cochlea were prepared for both SEM and TEM. The result of SEM showed that the degeneration and loss of stereocilium in each turn was significantly milder in the experimental group than in the control. Under TEM, outer and inner hair cells showed changes caused by kanamycin. In the experimental group, the mitochondrias were basically normal. The secondary lysosomes gathered under cuticular plate and supranuclear area. In the control group, the mitochondria showed pyknosis and high density, and multivesicular bodies were increased. The cytoplasm was swelling. There were many vacuoles produced by accumulation of liquid in the cytoplasm. Based on the findings of ultrastructural changes of cochlear hair cells, the mechanism of thyroxine against ototoxicity of kanamycin was discussed.
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PMID:[An electron microscopic study of thyroxine against ototoxicity of kanamycin]. 803 86

Isometric contraction to direct supramaximal tetanic stimulation of the anterior tibialis (AT) muscle was measured in 50 New Zealand White rabbits after ischemia and reperfusion. Ischemia was produced unilaterally by collateral ligation and temporary inflow control until AT muscle function decreased to < 5% of contralateral (control) AT muscle and the ischemic interval was recorded. Reperfusion was carried out in one of the following ways: group I (n = 20), release of vascular clamps (blood reperfusion [BR]); group II (n = 10), release of vascular clamps and simultaneous intraarterial administration of 50,000 units of urokinase (urokinase reperfusion [UR]); group III (n = 10), release of vascular clamps and simultaneous administration of 50,000 units of urokinase and 28 mg (5 units) of purified rabbit plasminogen (urokinase plasminogen reperfusion [UPR]); and group IV (n = 10), animals defibrinated to < 50 mg/dl with ancrod prior to ischemia and received BR (ancrod blood reperfusion [ABR]). During reperfusion, function was recorded every 60 min for 2 hr. Recovery of experimental muscle function is expressed as the percentage of contralateral control limb function. The mean ischemic interval (mean +/- SEM), to achieve < 5% of contralateral control limb function, was 206.7 +/- 9.9, 209.5 +/- 16.6, 221.7 +/- 12.5, and 272.0 +/- 14.2 min for animals in groups I-IV, respectively. The mean experimental muscle function (mean +/- SEM) following the ischemic interval was 3.2 +/- 0.8, 4.5 +/- 1.4, 4.4 +/- 1.2, and 3.3 +/- 1.0 for groups I-IV, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effect of hypofibrinogenemia and fibrinolysis on skeletal muscle function after ischemia and reperfusion. 827 73

Based on the SEM-images of mature granular sludge in ABR, the research process on fractal characteristics of these granules was built. The treatment and fractal dimensions calculation of the images were carried on through Photoshop, Newscan and Fips programs. The results showed that the boxing-counting dimensions of the mature granular sludge were more than 1.85, and the granules formed in the third and fifth compartments were more compact. The boundaries of the same granular sludge were fractal with the fractal dimensions of approximate 1.10, demonstrating the irregularity of the boundaries or surfaces, furthermore the surface of these granules formed in the first and fifth compartments was more irregular. It seemed that the compass dimensions of the granules boundary were a proof of irregularity of their surface. Moreover, there existed two scale scopes in calculating the compass dimensions of each granule, especially some of them with a range of one order of magnitude. A little discrepancy was appeared between box-counting and compass ways to calculating fractal dimensions. It will be important to build relationship between fractal dimensions with different scales and composition, structure, physico-chemical characteristics of granular sludge.
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PMID:[Fractal characteristics and scale dependence of mature granular sludge in anaerobic baffled reactor (ABR)]. 1621 80

Noise induced hearing loss (NIHL) is a disease that affects millions of Americans. Identifying genetic pathways that influence recovery from noise exposure is an important step forward in understanding NIHL. The transcription factor Foxo3 integrates the cellular response to oxidative stress and plays a role in extending lifespan in many organisms, including humans. Here we show that Foxo3 is required for auditory function after noise exposure in a mouse model system, measured by ABR. Absent Foxo3, outer hair cells are lost throughout the middle and higher frequencies. SEM reveals persistent damage to some surviving outer hair cell stereocilia. However, DPOAE analysis reveals that some function is preserved in low frequency outer hair cells, despite concomitant profound hearing loss. Inner hair cells, auditory synapses and spiral ganglion neurons are all present after noise exposure in the Foxo3KO/KO fourteen days post noise (DPN). We also report anti-Foxo3 immunofluorescence in adult human outer hair cells. Taken together, these data implicate Foxo3 and its transcriptional targets in outer hair cell survival after noise damage. An additional role for Foxo3 in preserving hearing is likely, as low frequency auditory function is absent in noise exposed Foxo3KO/KOs even though all cells and structures are present.
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PMID:Severe hearing loss and outer hair cell death in homozygous Foxo3 knockout mice after moderate noise exposure. 2843 53