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Query: UMLS:C0026837 (muscle rigidity)
 1,077 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In cats decerebrated by a midcollicular section, decerebrate rigidity developed that was not alleviated by phenytoin even in doses as great as 60 mg per kilogram. Chlorpromazine that depresses decerebrate rigidity in a dose-related fashion requires 1.5 to 2.0 mg per kilogram to exhibit an appreciable effect. In the presence of 20 mg per kilogram phenytoin, however, as little as 0.1 mg per kilogram chlorpromazine markedly reduces decerebrate rigidity. This drug combination did not impair neuromuscular transmission nor did it severely impair motor coordination in cats. Although phenytoin depressed muscle spindle discharges, this peripheral suppression was insufficient to abolish the rigidity. Phenytoin with or without chlorpromazine may be of value in suppressing muscle rigidity in some disorders of upper motor neuron lesions.
Neurology 1976 Sep
PMID:Suppression of decerebrate rigidity by phenytoin and chlorpromazine. 13 1

Emperor penguins breed during the cold antarctic winter. The males incubate the single egg while fasting for up to 4 mo and losing some 20 kg of their body mass. Fasting captive birds under outdoor conditions lost from 0.145 to 0.434 kg day -1. Mean resting metabolic rate, 49.06 W for 24.8 kg body mass, is 7 and 27%, respectively, higher than predicted from general metabolic equations for birds. Minimal thermal conductance, 1.31 W m-2 degrees C-1, is within the range for other birds. The lower critical temperature is about -10 degrees C; this can be related to large body size (20-40 kg) and to body shape, giving a smaller relative surface area than for other birds. Rigidity of the feathers explains why winds of moderate speed (up to 5 m s-1) have little effect on heat loss. At very low temperatures the behavior of huddling close together is essential in reducing metabolic rate. Without this behavior, survival during the long fast (up to four mo) at winter temperatures would be impossible.
Am J Physiol 1976 Sep
PMID:Thermoregulation in fasting emperor penguins under natural conditions. 97 Apr 75

Results from studies of cohort differences suggest that older and younger volunteers may differ in aspects other than age. In this study subjects, who had or had not been promised $10.00 payment for their participation, were compared on certain personality and intelligence factors. No differences between incentive conditions were observed for 2466 potential subjects on willingness to participate, nor for 591 subjects eventually tested on their scores on the Primary Mental Abilities Test, the Test of Behavioral Rigidity and Cattell's 16 PF. However, differences by incentive condition were observed on the intercorrelation matrices for women on Form B of the 16 PF. Results of these analyses suggest that, with few exceptions, supplying a monetary incentive to induce subjects to participate in a study does not significantly alter the characteristics of a volunteer sample with regard to age or sex.
Exp Aging Res 1976 Sep
PMID:Monetary incentive, age, and cognition. 101 61

The health condition of female cash register operators in relation to their working conditions was investigated. A questionnaire study revealed that cash register operators more frequently complained of general fatigue, headache, sleeplessness, and low back pain than female office machine operators or other female workers. Dullness and pain in the shoulder, arm, hand, and fingers especially on the right side were characteristic of cash register operators. Physical examinations in 1973 showed that 31.3% of 371 cash register operators suffered from muscle rigidity or tenderness; 13 were severely afficted and, 69 operators had to be either laid off, reassigned to other jobs, or given shorter working hours. Occupational cervicobrachial disorders were suggested to have been caused by repetitive upper limb motions combined with static load, an unfavorable working environment, and mental stress. Implementation of some improvements including shorter operation time, worker rotation, and adoption of electronic registers proved effective in reducing the number of sufferers of cervicobrachial disorders found during the 1975 physical examinations. But the improvements were not effective enough to alleviate fatigue of the neck, shoulder, and back due presumably to sustaining upper limbs while operating the keyboard.
J Hum Ergol (Tokyo) 1976 Sep
PMID:Health hazard among cash register operators and the effect of improved working conditions. 102 12

Intracellular free Mg2+ concentration ([Mg2+]i) was measured in isolated single fibres of Xenopus muscle using the fluorescent Mg2+ indicator furaptra. In resting muscle the [Mg2+]i was 1.7 mM in a Mg(2+)-free Ringer solution. There was no significant change in [Mg2+]i over 2 h in Mg(2+)-free Ringer solution. Elevating extracellular [Mg2+] to 40 mM for 5 min caused a small rise (0.13 mM) in [Mg2+]i. There was no detectable rise in [Mg2+]i after 5 min in Na(+)-free Ringer solution. These results suggest that the membrane is relatively impermeable to Mg2+ and that there was no detectable Na(+)-Mg2+ exchange over 5 min. When muscle fibres were fatigued by repeated tetani continued until force declined to about 40% of control, [Mg2+]i showed characteristic changes. During the early period of fatigue when force first showed a small decline and then became almost stable, [Mg2+]i was unchanged; during the final period of fatigue when force declined more rapidly, [Mg2+]i increased by 0.8 mM. Recovery of [Mg2+]i took about 30 min. Recovery of force was complex: tetanic force first declined (post-contractile depression) and then slowly recovered to control. Since the minimum force occurred at about the time when [Mg2+]i had recovered, it seems unlikely that post-contractile depression is caused by elevated [Mg2+]i. Rigor, produced by inhibiting oxidative phosphorylation and glycolysis, was associated with a larger increase (1.6 mM) in [Mg2+]i than fatigue. The rise in [Mg2+]i during fatigue and metabolic blockade could be explained as release of Mg2+ normally bound to ATP. A model of the metabolic changes and the resulting increase in [Mg2+]i explains our results reasonably well.
Exp Physiol 1992 Sep
PMID:Myoplasmic Mg2+ concentration in Xenopus muscle fibres at rest, during fatigue and during metabolic blockade. 141 55

The interrelationship of measures of rigidity-flexibility and of psychometric intelligence is examined. The latent factors of Attitudinal Flexibility, Motor-Cognitive Flexibility, and Psychomotor Speed are derived from the Test of Behavioral Rigidity, and factors of Inductive Reasoning, Spatial Orientation, Verbal Ability, Numeric Ability, Verbal Memory, and Perceptual Speed are derived from the Thurstone Primary Mental Abilities Test and the Educational Testing Service Kit of Factor-Referenced Tests. The data base in this study comes from the fifth wave of the Seattle Longitudinal Study (N = 1,628; age range, 22-95 years). The Rigidity-Flexibility factors were found to be independent of the cognitive domain. Also, longitudinal stability of the factor structure of the rigidity-flexibility domain was confirmed for 837 participants tested in both 1977 and 1984.
Psychol Aging 1991 Sep
PMID:Relationship between rigidity-flexibility and cognitive abilities in adulthood. 193 Jul 54

Tardive dyskinesia is a disorder secondary to prolonged treatment (from 18 months to 3 years) with antipsychotic agents, affecting approximately 15% to 20% of patients. Tardive dyskinesia is characterized by difficulty controlling involuntary movements of the small muscle groups, producing tic-like reactions, muscle rigidity, and difficulty maintaining muscle tone. It is a chronic and unrelenting disorder which may be permanent if not successfully treated. The mechanism of action is thought to be secondary to dopamine hypersensitivity resulting from prolonged deprivation of dopamine on the part of dopamine-sensitive receptors. Theoretically, these receptors have been deprived of the neurotransmitter by chronic treatment with antipsychotic drugs, which are recognized as dopamine-blocking agents. We present a case in which alprazolam was successfully used in treating tardive dyskinesia.
J Natl Med Assoc 1990 Sep
PMID:Tardive dyskinesia successfully treated with alprazolam. 221 17

Two sibling cases of cerebrotendinous xanthomatosis with parkinsonism were reported. One was a woman of 39 years old, and another was her sister of 36 years old. In both cases, febrile convulsion appeared on 1.5 year old, and mental deterioration, ataxic -spastic gait, cataract and swelling of Achilles tendons developed in order since entrance into elementary school. Five years ago, while they were in hospital at the first time, they were diagnosed as cerebrotendinous xanthomatosis by mental disturbance, cerebellar ataxia, pyramidal tract sign, histologically xanthomatous granuloma of Achilles tendons and hypercholestanolemia and family history of autosomal recessive trait. After the second admission, parkinsonism was noticed in addition to those findings above. Parkinsonism consisted of the following: Resting tremor of parkinsonian type, mild muscle rigidity of forearm and intrinsic-plus hand were observed in the elder sister, and generalized severe rigidity and bradykinesia in the younger sister. In both cases, brain CT showed the pontocerebellar atrophy, and the bilateral low density area in corona radiata, posterior portion of internal capsule, cerebral peduncle, tegmentum of midbrain and deep matter of cerebellum. Brain MRI also showed abnormal intensity in the same regions as on the brain CT. Administration of anti-parkinsonian drugs was challenged for the parkinsonism. Oral L-dopa test (500 mg) moderately improved parkinsonism in both cases. Therapy of diphenylpyraline hydrochloride (10 mg/day) entirely inhibited parkinsonian tremor and mild rigidity in the elder sister but was less effective for severe rigidity in the younger sister than administration of L-dopa.(ABSTRACT TRUNCATED AT 250 WORDS)
Rinsho Shinkeigaku 1990 Sep
PMID:[Parkinsonism associated with cerebrotendinous xanthomatosis]. 226 9

Systemic pretreatment with ketanserin, a relatively specific type-2 serotonin receptor antagonist, significantly attenuated the muscle rigidity produced in rats by the potent short-acting opiate agonist alfentanil. Following placement of subcutaneous electrodes in each animal's left gastrocnemius muscle, rigidity was assessed by analyzing root-mean-square electromyographic activity. Intraperitoneal ketanserin administration at doses of 0.63 and 2.5 mg/kg prevented the alfentanil-induced increase in electromyographic activity compared with animals pretreated with saline. Chlordiazepoxide at doses up to 10 mg/kg failed to significantly influence the rigidity produced by alfentanil. Despite the absence of rigidity, animals that received ketanserin (greater than 0.31 mg/kg i.p.) followed by alfentanil were motionless, flaccid, and less responsive to external stimuli than were animals receiving alfentanil alone. Rats that received ketanserin and alfentanil exhibited less rearing and exploratory behavior at the end of the 60-min recording period than did animals that received ketanserin alone. These results, in combination with previous work, suggest that muscle rigidity, a clinically relevant side-effect of parenteral narcotic administration, may be partly mediated via serotonergic pathways. Pretreatment with type-2 serotonin antagonists may be clinically useful in attenuating opiate-induced rigidity, although further studies will be necessary to assess the interaction of possibly enhanced CNS, cardiovascular, and respiratory depression.
Anesthesiology 1987 Sep
PMID:Ketanserin pretreatment reverses alfentanil-induced muscle rigidity. 311 50

Reduction in the anesthetic requirement of halothane by narcotics has been studied extensively in humans and animals. Problems of respiratory depression, cardiovascular depression, muscle rigidity, and abuse potential make narcotics less than ideal as supplements to general anesthesia with inhalational agents. Spiradoline, a clinical candidate, is a highly potent and selective kappa-agonist. As such it was considered important to study the effects of spiradoline on the minimum anesthetic concentration (MAC) of halothane required to block responses to noxious stimulation. The results of these experiments in rats showed a dose and plasma concentration-dependent reduction in halothane MAC over a wide range of subcutaneous doses of spiradoline (0.03 to 300 mg/kg). A maximum MAC reduction of 70% was obtained. Plasma levels of spiradoline (6 to 1800 ng/ml) were linearly related to dose. Measurement of blood pressure, heart rate, and PCO2 determined over the course of each experiment showed minor variations which would be acceptable if observed in a clinical setting. It is concluded that spiradoline has promise as an anesthetic supplement.
Anesth Analg 1988 Sep
PMID:Enhancement of anesthetic effect of halothane by spiradoline, a selective kappa-agonist. 341 91


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