摘要:

In order to determine the effects on the cochlea of circulatory disturbance in the basilar artery system, the cochlear action potential (AP) and the cochlear blood flow were measured in cats with the artery occluded. The occlusion was performed in the basilar, the anterior cerebellar and in the internal auditory arteries. During occlusion the decrease in the cochlear blood flow was greatest in the internal auditory artery and the least in the basilar artery. While the cochlear blood flow showed various levels of decrease depending on the occlusion site and the individual animal, the degree of AP alteration correlated with the decreased rate in the cochlear blood flow.

ISSN:0301-1569    

DOI:10.1159/000276226

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

Red cell basic ferritin (RCBF) was measured in 62 healthy subjects with normal hearing and 224 patients with different kinds of sensorineural hearing loss, compared with serum ferritin, haemoglobin, serum iron and circadian variation in the serum iron levels. The results showed that the RCBF concentrations in most kinds of sensorineural hearing loss were significantly lower than those in normal hearing status. It is conceivable that the RCBF assay can be used to evaluate the adequacy of iron stores that are useful in times of urgent iron needs and to diagnose relative iron deficiency in those patients with some other normal laboratory assays related to iron metabolism.

ISSN:0301-1569    

DOI:10.1159/000276227

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

Vancomycin (V) – a polypeptide antibiotic – is the drug of choice in severe infections with multiresistant staphylococcus spp. Due to the multimorbidity of the patients receiving V, the interactions with known ototoxic agents and the lack of an audiometric documentation, earlier clinical reports of V-associated hearing loss must be carefully interpreted. To elucidate this topic, a controlled animal study considering nonspecific effects was performed. 40 albino guinea pigs with positive Preyer’s reflex and normal hearing were used. The hearing function was controlled by means of brainstem auditory evoked potentials before and after intraperitoneal administration of V (75, 150, 300 mg/kg b.w. for 11–17 days), gentamicin (60 mg/kg b.w. for 26 days), neomycin (100 mg/kg b.w. for 17 days) and sodium chloride solution. The cochleas were dissected for hair cell counting by the surface preparation technique. Additionally, the serum concentrations of V were measured. As a result there was no significant difference in hearing loss between the controls and the animals treated with 75 and 150 mg V; toxic doses of 300 mg V led to a certain threshold elevation after click stimuli, but not after trapezoid stimuli of 1, 4 and 8 kHz. On the other hand, the aminoglycosides as a positive control caused an obvious hearing loss after click and trapezoid stimuli, which was correlated to the amount of outer hair cell loss. Renal damage could be excluded by histological examination of the kidneys and estimation of creatinine in serum. Therefore, treatment with moderate doses of V comparable to clinical conditions does not exhibit a specific ototoxicity as compared to the aminoglycosides. However, serum levels of V should be controlled as a safety measure in older patients and in patients with impaired renal f

ISSN:0301-1569    

DOI:10.1159/000276228

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

The fine structure of dark cells and melanocytes of the crista ampullaris was studied by using the freeze-fracture technique. For these studies we used normally pigmented guinea pigs, as well as those with experimentally induced endolymphatic hydrops. The results suggest the vestibular secretory region to be an area of unusually high dynamics. In the experimental animals the cell processes of the melanocytes gain closer contact with the dark cells as well as with the subepithelial capillaries. There is considerable evidence of secretory transfer of different substances, especially ions.

ISSN:0301-1569    

DOI:10.1159/000276229

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

An experiment was carried out to examine the effects of TRH on the acquisition of vestibular habituation in guinea pigs. Vestibular habituation was obtained in approximately 12 days by vestibular training of unidirectional velocity steps imposed 30 times daily for 15 days, and was retained for more than 2 weeks even though the daily vestibular training was ceased. When compared with the time to attain the maximum level of the vestibular habituation depicted through decrement of postrotatory nystagmus between control and thyrotropin-releasing hormone (TRH) injection groups, the TRH injection group took significantly longer than the control group. Thus the results have shown that the systemic administration of TRH could result in the retardation of the acquisition of vestibular habituation. This could be due to the depressant action of TRH on the cerebellar neurons.

ISSN:0301-1569    

DOI:10.1159/000276230

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

Sectioning of the unilateral vestibular nerve of the bull frog resulted in tilting of the head and the body. The angle of head tilt was periodically measured. The angle returned to 0° in an average of 7.3 weeks. A morphological study demonstrated normal structure of the sensory epithelia and a well-regenerated nerve bundle. Also, discrete action potentials could be recorded from the nerve centrally to the cut site of the vestibular nerve. These results indicate that recovery from the tilting involves two mechanisms, one being central compensation and the other reactivation of the sensory cell-nerve unit

ISSN:0301-1569    

DOI:10.1159/000276231

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

Dynamic posturography (PG) is a new objective method to study functional performance in diseases affecting balance. It measures muscle response latencies and sway angles to standardized alterations of a moveable platform and moveable surroundings. Twenty-eight patients with polyneuropathy (PN) were studied by clinical investigation, vibrametry, neurography, and dynamic PG. The results of dynamic PG and vibrametry were compared with those of 29 healthy controls. In the patients with PN, clinical scores correlated to the latencies of the muscle response when the platform was suddenly moved forward, and to equilibrium performance (sway angles) in dynamic PG test conditions with eyes closed and the platform either stable or ‘sway-referenced’. That is, the platform moves in response to the patient’s anterior-posterior sway, creating a disturbed proprioceptive input to the brain. Clinical scores also correlated to the equilibrium performance when both platform and surroundings were sway-referenced. In conclusion dynamic PG, in addition to clinical investigations and neurophysiology, is a valuable and objective method for estimating the equilibrium performance in patients wi

ISSN:0301-1569    

DOI:10.1159/000276232

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

The histochemical properties of mucosubstances within the sinus mucosa were examined in rabbits affected with experimental sinusitis, induced either by blocking the maxillary sinus ostium (occlusion group) or in addition by an inoculation of Streptococcus pneumoniae (pneumococcal group). An increase in periodic acid-Schiff positive epithelial secretory cells was found, as well as regeneration of goblet cells in the epithelium from the 2nd week. The goblet cells proved to contain periodate-reactive acid mucins, particularly during the early stages, as well as periodate-unreactive, purely acid mucins which were prevalent throughout the study. Among the alcian blue positive goblet cells, 0–40% (usually 5–20%) contained acid sialomucins, while the rest stained positive for sulpho-mucins. The submucosal glands and the large lateral nasal and maxillary glands were not histochemically influenced by the induced inflammatory state. No obvious difference in the histochemical staining pattern was seen between the two groups. A comparative microbiological analysis of the groups was also included in the st

ISSN:0301-1569    

DOI:10.1159/000276233

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

The evolution of crushed cartilage grafts in a growing nasal septum of young rabbits was histologically investigated. Crushing leads to necrosis of the greater part of the graft. The characteristic distribution of surviving cells in isolated areas at the surface of the graft reflects different mechanical properties of the centrally and peripherally located cartilage. The necrotic parts are eliminated and replaced by new cartilage formed by surviving chondrocytes or perichondrium. The result is a complex structure composed of two types of cartilage and of fibrous tissue without any distinct organization, but nevertheless capable of growth. However, it lacks strength to transform growth into adequate lengthening of the septum. Subsequently, this will lead to the development of multiple deviations. It is concluded that crushed cartilage is no suitable implant for the reconstruction of parts of the septum which are essential in supporting the outgrowth of the nose.

ISSN:0301-1569    

DOI:10.1159/000276234

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

The cartilaginous nasal septum of the child is often involved in trauma or congenital deformation. In perspective of its role in postnatal growth of the midface, the wound healing of septal cartilage in reaction to various surgical procedures was studied in young rabbits. It was concluded that (1) elevation of mucoperichondrium does not induce significant histologic reactions in the septal cartilage and (2) the wound reaction of cut edges includes only a ± 0.8-mm-deep zone and lasts no longer than 2 weeks, resulting in a stump, encapsulated by fibrous tissue. Reconnection of separated parts occurs 2 weeks after surgery, mostly by merging of the perichondrial layers. Reimplantation of resected cartilage does not lead to normalisation of septal growth. This is not caused by extensive necrosis, loss of morphological organisation or decreased growth potential of the reimplanted cartilage. The essential factor seems to be dislocation (duplication, angulation) of the implant versus the non-mobilised parts of the septum preventing the growth of the implant to contribute fully to the lengthening of the total septum

ISSN:0301-1569    

DOI:10.1159/000276235

出版商:S. Karger AG    

年代:1991

数据来源: Karger