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Biomedical subjects

G C Leslie

Publications and source records attributed to G C Leslie.

13 recordsLinked to original sources
PubMed1989

The effect of EU4093 (azumolene sodium) on the contraction of intrafusal muscle in the soleus muscle of the anaesthetized rat.

1. EU4093 (azumolene sodium) is a direct acting, skeletal muscle relaxant with structural similarities to dantrolene sodium in that the para-nitro phenyl group of dantrolene sodium is replaced by a para-bromo phenyl group. 2. The effect of EU4093 on the twitch of the intact rat soleus preparation is nearly maximal at a dose of 20 mg kg-1. This dose of EU4093 reduces the amplitude of the twitch to 31.9% of the control value. By comparison, dantrolene sodium reduced the twitch amplitude to 31.3% of the control value at a dose of 5 mg kg-1. 3. The contraction of intrafusal muscle as measured by the response of spindle afferent discharge was also reduced by EU4093. 4. The most significant difference between the effect of EU4093 and dantrolene sodium on the contraction of intrafusal muscle was that EU4093 had an appreciable depressant action at high stimulation frequencies at which dantrolene sodium had only a minimal relaxant effect on the intrafusal muscle contraction. 5. The significance of this difference in the actions of EU4093 and dantrolene sodium is discussed in terms of the possible effect of the drug in the intact animal and human patient. It is concluded that, because the discharge frequency is not likely to move into the high frequency range at which dantrolene sodium and EU4093 have significantly different effects, the overall effect of these two drugs is likely to be similar.

Anesthesia↗
PubMed1988

Observations on the applicability of the Wartenberg pendulum test to healthy, elderly subjects.

Wartenberg developed his pendulum test as a simple but precise test to assist examination of muscle tone in patients with Parkinson's disease. It has recently been reintroduced, and computerised, to evaluate spasticity in young hemiplegics. The results are reported on the highly successful application of this computerised test to large numbers of healthy, elderly subjects. The data have provided normal values for a number of measurements. Analysis of variance has shown that differences between individual subjects account for a major part of the total variabilities seen in all measurements taken. Factors such as position, leg and time trend contribute very little to total variation and, for practical purposes, can be ignored.

Adult↗
PubMed1988

Does the Wartenberg pendulum test differentiate quantitatively between spasticity and rigidity? A study in elderly stroke and Parkinsonian patients.

The results of applying the Wartenberg pendulum test to the assessment of muscle tone in populations of stroke and Parkinsonian patients are described. The test was able to distinguish between increased muscle tone of the spastic or rigid type. The Parkinsonian patients showed a marked reduction of the maximum velocity of the leg swing, with the relaxation index tending to a value of about one. In contrast the affected limb of stroke patients showed a lesser reduction of the velocity of the swing, the relaxation index tending to a value of less than one.

Aged↗
PubMed1986

How is ventilation maintained in the presence of the muscle relaxant, dantrolene sodium? A study in the anaesthetized rat.

The effects of intravenous injection of the muscle relaxant dantrolene sodium on ventilation, integrated EMG of external intercostal muscles and motor unit discharge in these muscles were measured in anaesthetized rats. Dantrolene sodium was administered in a carrier solution at pH 10. The carrier was not responsible for the effects seen on dantrolene sodium infusion. Dantrolene sodium (5 mg kg-1 body weight) reduced inspired ventilation (VI) on average from 308 +/- 106 ml min-1 (s.d., n = 8) in the control period to 247 +/- 118 ml min-1 (n = 8) after dantrolene sodium. Expired ventilation was reduced likewise from 274 +/- 132 ml min-1 (n = 8) to 229 +/- 109 ml min-1 (n = 8). These changes are significant at P less than 0.05. The integrated EMG was increased by 40.0 +/- 29.3% (n = 9), a change significant at P less than 0.001. Dantrolene sodium not only decreased the mean interspike interval of individual motor units by 16.2 +/- 11.1% (n = 13), a change significant at P less than 0.001, but also increased the duration of the burst of activity of each individual motor unit on average by 36.2 +/- 52.4% (n = 13), a change significant at P less than 0.05. The recruitment of additional motor units was also effected by dantrolene sodium. These units did not behave in any noticeably different manner from units previously active. It is concluded that the nervous system compensates for the effect of dantrolene sodium only to a limited extent by increasing the frequency of discharge of active motor units. Recruitment ofadditional motor units and increased burst duration play at least as important a role.

Anesthesia↗
PubMed1978

Some observations on the efferent innervation of rat soleus muscle spindles.

In the small segmental tail muscles of the rat beta fibres provide exclusively the dynamic fusimotor control, while gamma fibres provide exclusively the static fusimor control. The present experiments were made to investigate the fusimotor innervation of spindles in a large muscle of the rat, the soleus, and thus to determine the occurrence and significance of beta innervation in this muscle. Our results have revealed no case of beta innervation in the rat soleus. As a consequence of our experimental method, however, we would not claim that beta innervation does not exist in the soleus, only that it must play an insignificant role relative to that seen in the tail segmental muscles. Investigations of the fusimotor innervation of eight spindles were sufficiently complete to warrant detailed illustration. The number of gamma fibres ranged from two to four. In every case the slowest conducting gamma fibre was dynamic. However, the conduction velocity spectra for the static and dynamic gamma fibres to rat soleus overlap to such an extent that it is impossible to use conduction velocity as the sole guide to functional gamma fibre classification. The pooled results from the eight spindles fully investigated provide a ratio of static to dynamic gamma fibres of approximately 1:1. Other evidence discussed in the paper suggests that in the muscle nerve the ratio is considerably higher. These differences are reconciled if the dynamic gamma fibres branch more profusely and innervate more spindles than do the static gamma fibres.

Animals↗
PubMed1978

A low pass filter with amplifier for measurement of active and passive tensions of skeletal muscle in vitro.

When displaying and measuring passive and active twitch tensions developed by skeletal muscle in vitro, the problems of amplification may be resolved by recording two traces. One, recorded at relatively low gain, is used for measurements of twitch tension amplitude. The other, recorded simultaneously, is a modified version of the first trace, in which the voltage signals are passed through a suitably constructed low pass filter, amplified and displayed. This second trace, recorded at relatively high gain, is used for measurements of changes in passive tension and contracture responses of relatively small amplitude.

Amplifiers, Electronic↗