PubMed · 7433962
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Y L Jing. 1980. [Respiratory function under high air pressure].. https://pubmed.ncbi.nlm.nih.gov/7433962/
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In order to study interocular temporal coupling in the initiation of learned symmetrical blinking, experiments were carried out on cats trained to blink in response to a 500-ms tone paired with 100-ms airpuffs randomly delivered to either eye (alternate airpuff; 6 animals) or simultaneously directed to both eyes (bilateral airpuff; 4 animals) 400 ms after tone onset. In spite of the fact that differences in conditioned response (CR) latencies of the right and left eye varied in a wide range between positive and negative values in all subjects, a statistically significant difference between the mean CR latencies of the two eyes (further called side superiority) was found in 6 animals, of which 4 were trained by alternate airpuff and 2 by bilateral airpuff. Superiority of the right eye was found in 3 animals and the opposite was observed in the other 3. Analysis of the differences between CR latencies of the two eyes showed that side superiority was not due to the ability of one eye to give CRs consistently shorter than those of the other eye, but it crucially depended on the higher proportion of trials in which the superior eye led. The ability to give simultaneous CRs by the two eyes was found inversely related to the mean CR latency per session and subject. Regression analysis showed that power equations best described these relationships. In all animals, the frequency distribution of simultaneous CRs paralleled the frequency distribution of all CRs. In spite of a considerable trial-by-trial variability in the temporal relationships between CR latencies of the two eyes, clear-cut linear correlations were found by plotting the mean CR latencies of the right and left eye per both session and subject. The results reviewed in this paper are best accounted for by suggesting that blink onset of the two eyes is independently controlled by two distinct command signals and is modulated by bilaterally-balanced and lateralized influences.
OBJECTIVE: To report on the essential performance characteristics of two brands of disposable air turbine handpiece and on aspects of their safety and convenience for clinical use. MATERIALS AND METHODS: Oralsafe and Feathertouch disposable handpieces were characterised using a variety of techniques in respect of the following: turbine rotor radius, equivalent orifice radius, stall torque coefficient, pressure effectiveness, power index, efficiency index, sound level and instrument retention force. RESULTS: Free-running speed versus pressure curves for many of the disposable handpieces showed marked deviations from the expected smooth form. Considerable variation between examples of each type was found in most measured values. Evidence of eccentric rotors and high bearing friction was not found. CONCLUSIONS: Both brands of disposable handpiece had a number of problems: poor performance, vibration, excessive noise, variability of behaviour, poor bearings. Use of these devices is difficult to recommend. Improvement in design seems necessary.
Negative pressure (NP) within the upper airway (UA) excites the activity of the genioglossus muscle and other UA dilators. For unknown reasons this reflex response is attenuated during sleep. Sleep reduces skeletal muscle tone, therefore we hypothesized that the magnitude of the pressure reflex is modulated by muscle tension. We have compared the threshold and the magnitude of the reflex response to laryngeal NP before and during muscle relaxation in 16 rabbits. The threshold increased from 7 +/- 2 (mean +/- S.D.) to 17 +/- 4 cm H2O. Peak amplitude during NP pulse dropped from 167 to 139 arbitrary units (a.u.) for the hypoglossal nerve (n.XII) and from 134 to 114 a.u. for the facial nerve (n.VII). Independently of the pressure reflex muscle relaxation reduced the phasic n.XII activity by 18% and tonic activity by 20%. We conclude that muscle atonia attenuates n.XII activity and the response to UA pressure change. Our findings when extrapolated to state of sleep suggest that sleep-induced muscle relaxation may be an independent factor suppressing pressure reflex.