摘要:

The endolymphatic space of pigeons was studied by using double-barrelled electrodes with a potassium liquid ion exchanger. The K+ activity of the endolymph was 155 mM in the cochlea and 133 mM in the ampulla, respectively. Positive DC potential in the cochlea (+14.5 mV) was much lower than in guinea pigs (+80 mV) whereas in the ampulla of pigeons the DC potential (+7.4 mV) was 2 times higher than that of guinea pigs (+3.9 mV). General application of ethacrynic acid in pigeons induced a weak change in DC potential and no typical intercellular edema in the cochlea and ampulla. Local application of ethacrynic acid and ouabain in the cochlea and ampulla of pigeons induced a negative DC potential of between ––30 and ––40 mV. This negative DC potential was higher than the anoxia-induced negative potential. Short hypoxia during a drug-induced DC potential resulted in a decrease in DC potential above the diffusion potential. Below the diffusion potential additional hypoxia increased the DC potential independent of the cause of intox

ISSN:0301-1569    

DOI:10.1159/000275899

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The cochlear microphonics (CM), endocochlear potential (EP) and potassium ion activities in the endolymph and perilymph were measured in guinea pigs which received daily successive intramuscular injections of 500 mg/kg of body weight of kanamycin sulfate. Preyer’s reflex threshold at 8 kHz began to increase after the 5th day of kanamycin treatment and disappeared on the 11 th day. The maximum output of CM at 8 kHz began to decrease with a time course similar to Preyer’s reflex. The potassium ion activities in the endolymph and perilymph and the EP did not change appreciably through all experimental days. The magnitude of the negative EP decreased in parallel with the reduction in CM and the relative potassium conductance (Gk) between the endolymph and perilymph. These results lend support to the hypothesis that the site of production of the negative EP is probably in the hair cells and that the negative EP is mainly dependent on the permeability of the potassium ions in the organ of Co

ISSN:0301-1569    

DOI:10.1159/000275900

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The cochlear and cerebral blood flow were simultaneously measured with the microsphere method in albino rabbits before and after administration of prazosin (0.5 mg/kg body weight) and before and during an increase in intracranial pressure (ICP) and intraco-chlear pressure. Increments in ICP were induced by intracranial infusion of Ringer solution prewarmed to body temperature. The increments were accompanied by an intravenous administration of prazosin to abolish the Cushing effect. The cochlear blood flow was unaffected by the intravenously administered prazosin. A decrease was found when the perfusion pressure of the cochlear, i.e. mean arterial blood pressure minus ICP fell below 5 kPa.

ISSN:0301-1569    

DOI:10.1159/000275901

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

A number of cases with typical positioning vertigo (BPPV) show a unilateral vestibular hypofunction (UVH) by caloric testing. However, treatment by habituation exercises (VHT) improves vertigo independently of the presence of UVH. Moreover, VHT has no influence upon the results of caloric and rotation tests. These findings prove the independence of the pathogenetic mechanisms of the peripheral vestibular disturbances UVH and BPPV.

ISSN:0301-1569    

DOI:10.1159/000275902

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Electrical brain activity and eye movements were recorded in 10 intact and 6 unilaterally labyrinthectomized rabbits, each with implanted electrodes. The frequency of optokinetic nystagmus (OKN) and a 10-second aggregate of theta waves in the dorsal hippocampus were determined after exposure of the animals to sound, vibration and optokinetic stimulation. Each stimulus used caused significant increases in OKN and theta activity. Vibratory stimuli caused stronger increases in OKN and theta activity than did sound stimuli. Not only was OKN significantly reduced after unilateral labyrinthectomy (UL), but alerting the rabbit with sound or vibration failed to restore the responses to normal, and hippocampal EEG responses to sound, vibration or optokinetic stimulus were significantly reduced. The findings indicate that a visual orientation reflex is normally improved by simultaneous sensory stimulation. Reduced response to stimuli after UL affects not only orientational reflexes but other sensory responses as well, and is accompanied by a reduced state of alertness.

ISSN:0301-1569    

DOI:10.1159/000275903

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The maximal expiratory flow-volume (MEFV) and maximal inspiratory flow-volume (MIFV) curve present maximal attainable flows, plotted against the displaced volume at the mouth during a forced expiratory manoeuvre from total lung capacity (TLC) and a subsequent forced inspiratory manoeuvre from residual volume (RV), respectively. Depending on the glottic resistance characteristics, the usual flow limitation may be absent during forced expiration, drastically influencing the form of MEFV curves. During forced inspiration however, the flow remains effort-dependent. We tested this hypothesis by comparing the form of MEFV and MIFV curves, and the glottic resistance characteristics, before and after an endolaryngeal superolateralisation of a vocal cord, in 12 patients with bilateral vocal-cord paralysis. Peak expiratory and inspiratory flows were estimated with the aid of the measured glottic resistance characteristics on the assumption that the maximal alveolar pressures were normal during the manoeuvres. The estimated values agreed well with measured values. The form of the MEFV and MIFV curves was also found to be closely linked to the glottic resistance characteristics. It is concluded that the MEFV and MIFV curves are sensitive indicators of flow limitation in patients with upper-airway obstructions.

ISSN:0301-1569    

DOI:10.1159/000275904

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

During a maximal forced expiration from total lung capacity (TLC) in normal human subjects flow limitation will occur (i.e., the flow will become independent of muscular effort) after the initial part of the expiratory manoeuvre. Flow limitation starts at the flow that causes a pressure drop in the bronchial tree large enough for the generation of a flow-limiting segment. In patients with upper-airway obstruction such as laryngeal obstruction or tracheal stenosis, the upper-airway resistance may keep the flow so low that flow limitation cannot arise. The present theoretical study confirms that glottic resistance does not prevent flow limitation from arising in normal human subjects. On the other hand, the mean glottic resistance characteristics measured for 19 patients with bilateral vocal-cord paralysis were found to be such as to prevent flow limitation. This means that in such patients and also in patients with other types of upper-airway obstruction flow may remain effort-dependent throughout the forced expiratory manoeuvre or in any case during much more of this manoeuvre than normal.

ISSN:0301-1569    

DOI:10.1159/000275905

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Strain 2 guinea pigs bearing an intradermally growing already lymphogenetically metastasized line 10 tumor received intralesional chemotherapy with either cisplatin or vincristine. After successful treatment with cisplatin and low-dose vincristine, nearly all animals developed tumor-specific immunity. This phenomenon was not observed in animals treated with high-dose vincristine. Possible mechanisms of generation and alteration of primary T-cell-induced posttherapeutic tumor immunity are discussed.

ISSN:0301-1569    

DOI:10.1159/000275906

出版商:S. Karger AG    

年代:1987

数据来源: Karger

ISSN:0301-1569    

DOI:10.1159/000275907

出版商:S. Karger AG    

年代:1987

数据来源: Karger