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At least 109 records · Page 6Linked to original sources
PubMed1975

[The second electromyographic study of surgical curarization with AH.8165, a new pachycurare derivative of azobis-arylimidazo(1-2a) pyridinium].

This second electromyographic study of AH-8165, a product derived from azobis-arymilidazo-(1-2a) pyridinium, carried out with a special apparatus which both stimulates and records, specifies the characteristics of the neuro-muscular block induced by this new non-depolarizing type curarizing substance while taking into account the usual factors of the curarimimetic variability of action. After an initial dose of 1 mg per kg of bodyweight, we notice particularly: -the lapse of time required for a complete block (90 s), its intensity and duration (normally total during at least one hour) -the morphology of the electromyogram during the curarization and the decurarization either spontaneous or induced by Neostigmin with in particular -the muscular fatigability after repeated stimulation following curarization and chiefly during decurarization, chronological data und electro-myographic aspects which are found as well after a reinjection of AH-8165 equivalent to the half of the previous one.

Action Potentials↗
PubMed1984

Ventilatory response to progressive curarization in patients during light halothane, N2O in O2 anaesthesia.

The effects of progressive curarization on spontaneous ventilation were studied in 23 patients during light halothane-nitrous oxide-oxygen anaesthesia. In 11 patients, in whom the end-expiratory CO2 concentration and evoked mechanical response were recorded, increasing curarization caused first a slow CO2 accumulation and later an abrupt ventilatory impairment at a twitch tension of between 5 and 50% of original muscle strength. In 12 patients, in whom the evoked integrated hypothenar EMG, spontaneous frontal EMG and mean frequency and amplitude of the EEG were recorded, the spontaneous frontal EMG and ventilation diminished within 3 min, following the first 5 mg dose of tubocurarine. At this stage muscle strength, indicated by the amplitude of the evoked EMG and the train-of-four ratio, was unchanged. Repeated 5 mg doses of tubocurarine caused an almost linear decrease in ventilation and an increase in end-tidal CO2 concentration without affecting the rate of breathing until the sudden impairment of ventilation that occurred usually after the fourth dose of tubocurarine. The EEG changes during curarization were minimal and no common trend was seen. The results suggest that tubocurarine may be given to anaesthetized patients in a dose which is too small to produce, using the evoked EMG, a detectable neuromuscular block, but is sufficient to cause ventilatory depression without a compensatory increase in the rate of breathing.

Adult↗
PubMedDate not supplied

The regional curare test and electrophysiologic diagnosis of myasthenia gravis: further studies.

Five hundred consecutive patients were evaluated for myasthenia gravis with repetitive stimulation of the median and ulnar nerves. Axillary nerve stimulation and repeated stimulation of wrist nerves following regional curare administration to the hand were performed when necessary. Abnormal responses were seen in 95% of 297 patients with generalized disease and in 35% of 54 patients with ocular disease, all of whom were clinically responsive to anticholinesterases. Identical responses were also seen in 32% of 124 patients with possible generalized disease, all of whom lacked clinical responsiveness to anticholinesterases. Abnormalities occurred following regional curare administration in 29% of 224 patients with normal responses during repetitive stimulation alone. This program for evaluating patients with suspected myasthenia gravis continues to be successful, safe, and practical.

Curare↗
PubMed1988

Regenerated fibers of the lamprey spinal cord can coordinate fictive swimming in the presence of curare.

Recently evidence was presented that, following transection, spinal cords of larval lampreys could regenerate functional connections. The demonstration in isolated spinal cord-notochord preparations consisted of fictive swimming coordinated across the lesion site. In the study reported here curare was added to the bath to eliminate the possible contribution from reflexes mediated by contractions from any remaining muscle fibers attached to the notochord. Coordination remained in the presence of curare, adding further evidence that indeed the regenerated fibers formed functionally appropriate connections.

Animals↗
PubMed1993

Magnetic resonance imaging of the fetus: a study of 20 cases performed without curarization.

Twenty patients underwent magnetic resonance imaging (MRI) at a mean gestational age of 32 weeks. There were 12 patients with suspected fetal brain abnormality and four with intrauterine growth retardation (IUGR), while the remaining four cases were studied for other reasons. The MRI examinations were performed on a 0.5 Tesla machine, with surface coils. One minute acquisition time T1 sequences were used. All the studies were performed without fetal curarization, and only under maternal sedation using flunitrazepam given per os 1 h before MRI examination. Three examinations were incomplete because of fetal movement artefacts. In the remaining cases, MRI allowed the examination of fetal brain anatomy. In five cases, it helped to differentiate isolated hydrocephalus and corpus callosum agenesis. Sub-ependymal nodules were depicted in a case of fetal tuberous sclerosis. One suspected arachnoid cyst was proved to be an ultrasound artefact. Decreased fetal fat on MR images was correlated with low birth weight in cases of IUGR. Due to its better spatial resolution, ultrasonography was more accurate for the diagnosis of facial and lumbar anomalies. Fetal MRI may be performed without curarization. Surface coils allow the detailed analysis of brain parenchyma, and thus MRI is especially useful in the difficult prenatal diagnosis of fetal brain abnormalities.

Adipose Tissue↗
PubMed1979

Activation of membrane Na+/K+-ATPase of mouse skeletal muscle by acetylcholine and its inhibition by alpha-bungarotoxin, curare and atropine.

The effect of acetylcholine and of three cholinolytic compounds (alpha-bungarotoxin, curare and atropine) on electrogenic Na+/K+ pump and activity of the membrane Na+/K+-ATPase of mouse skeletal muscles was studied. It was found that acetylcholine potentiated both the muscle electrogenic ionic pump and the Na+/K+-ATPase activity of crude membrane fractions. The cholinolytic drugs had inhibitory effects on both parameters, with the exception of curare which was ineffective in blocking the electrogenic ionic pump.

Acetylcholine↗
PubMed1975

A comparison of memory under three methods of anaesthesia with nitrous oxide and curare.

Sixty-three volunteer patients participated in an investigation disigned to evaluate memory of the surgical experinece with three different methods of balanced nitrous oxide-curare anaesthesia. Two of the methods (Liverpool and Roosevelt protocols) used thiopentone for induction but did not utilize any neuroleptic drug, while the third (Diazepam protocol) used the tranquilizer diazepam in combination with morphine for both premedication and induction. In general, the results suggest that all three variations are successful in producing anaesthesia and that patients have no recall of the major portion of the surgical procedure. The major differences among the groups were exhibited in the post-operative periods. These findings suggest that diazepam affects the emotional quality associated with memory and thus aids the patients by reducing both the incidence of noxious psychological reactions and the possibility of severe emotional trauma. Finally, the findings also suggest the importance of using a narcotic analgesic as part of nitrous oxide-curare anaesthesia.

Adjuvants, Anesthesia↗
PubMed1985

Life span and age-related changes in activity level of the rotifer Asplanchna brightwelli: influence of curare.

The rotifer Asplanchna brightwelli shows a continuous decline in swimming activity through the course of its 5-day life span. This activity loss occurs at a slower rate when rotifers are treated with very low dosages (0.00025% to 0.0005%) curare. Rotifers treated with these low dosages of curare have a significantly longer life span than that of untreated control rotifers.

Activity Cycles↗
PubMed1990

Normal expression of myosin fast alkali light chain 3 in the hindlimb muscle of chick embryos paralyzed with curare.

We have used a monoclonal antibody (Mab) raised against the fast alkali light chains of quail pectoral muscle myosin to study the expression of MLC1f and MLC3f in the hindlimb muscle of a staged series of control chick embryos and 16-day embryos that had been paralyzed with curare. The Mab (QBM-2) is highly specific for the fast myosin alkali light chains of chick, hamster, and human muscle myosin. On Western blots, MLC1f is detected in hindlimb actomyosin at all of the stages examined, whereas MLC3f cannot be detected until Embryonic Day 14 (E14). Most of the E16 embryos that had been paralyzed with curare since E4 express detectable levels of both MLC1f and MLC3f in their hindlimb muscles, even though embryos incubated under these conditions do not exhibit spontaneous limb movements. Contrary to other reports, our results demonstrate that muscle contraction is not required for the accumulation of MLC3f. In light of our previous finding that innervation is essential for MLC3f accumulation in limb buds grafted onto the chorioallantoic membrane of chick hosts, these results suggest that some neural influence other than contraction, possibly a trophic factor, may play a role in the developmentally regulated expression of MLC3f in avian limb muscle.

Animals↗
PubMed1996

[Gynecologic laparoscopy with or without curare].

OBJECTIVE: To assess physiological changes and operating conditions during general anaesthesia with or without neuromuscular blockade in patients undergoing gynaecologic laparoscopy. STUDY DESIGN: Prospective, randomized, double-blind study. PATIENTS: Fifty non-obese patients, mean age 31 years, randomly allocated into either a group of 25 with curare (AC) or a group of 25 without curare (SC). METHODS: All patients were anaesthetized with propofol (2.5 mg.kg-1), sufentanil (0.4 microgram.kg-1) midazolam (2 mg) and N2O-O2. In addition, those of the AC group were given atracurium 0.25 mg.kg-1 for intubation, followed by additional boluses to maintain twitch height < 10% of the control value. Blood pressure, heart rate, peak airway pressure, end-tidal carbon dioxide pressure were recorded before and during pneumoperitoneum maintained at a pressure of 15 mmHg. Operating conditions were assessed at 10-min intervals, using a four point scale. RESULTS: In both groups, blood pressure and heart rate decreased following induction. The decrease in blood pressure was more important in the SC group at 5 min and before pneumoperitoneum (25 vs 15%); P < 0.05). The time course of PETCO2 and peak airway pressures were similar between groups. Operating conditions were not influenced by the muscle relaxant. CONCLUSIONS: Neuromuscular blockade influences neither most of the clinical haemodynamic and respiratory changes induced by pneumoperitoneum for gynaecologic laparoscopy not the operating conditions.

Adult↗
PubMed1989

Acetylcholinesterase in chick embryo latissimus dorsii muscles: effects of curarization and electrical stimulation.

The accumulation of acetylcholinesterase (AChE), the changes in AChE-specific activity and in AChE molecular form distribution were studied in slow-tonic anterior latissimus dorsi (ALD) and in fast-twitch posterior latissimus dorsi (PLD) muscles of the chick embryo. From stage 36 (day 11) to stage 42 (day 17) of Hamburger and Hamilton, the AChE-specific activity decreased, while the relative proportion of asymmetric A 12 and A 8 forms increased. Repetitive injection of curare resulted at stage 42 (day 17) in a decrease in AChE-specific activity, in the accumulation of the synaptic AChE and in the expression of AChE asymmetric forms. Electrical stimulation at a relatively high frequency (40 Hz) of curarized ALD and PLD muscles resulted in a normal increase in AChE asymmetric forms, whereas a lower frequency (5 Hz) resulted in a dominance of globular forms. Both patterns of stimulation partly prevented the loss in synaptic AChE accumulations. These results suggest that in chick embryo muscles, muscle activity and its rhythms are involved in the normal evolution of AChE.

Acetylcholinesterase↗
PubMed1966

Curare as a neuromuscular blocking agent in insects.

Topical application of curare produced no effects on electrical activity in single flight-muscle fibers of the fly Sarcophaga. However, the intraabdominal injection of curare induced a neuromuscular block similar to that described for vertebrates. The general refractoriness of some insects to chemical agents may well be due to the method of application.

Animals↗
PubMed1979

Membrane surface potential changes may alter drug interactions: an example, acetylcholine and curare.

Curare is known to be less effective as an acetycholine antagonist when the divalent cation concentration of the extracellular solution is increased. This observation can be accounted for by the negative surface potential on the end plate; an increase in divalent cation concentration decreases the negativity of the surface potential and thereby lowers the concentrations of cations at the membrane-solution interface. The concentration of divalent cations, such as curare, will be reduced more than the concentration of univalent cations, such as acetylcholine. The observations can be accounted for by a surface potential of about -50 millivolts. The same principle can explain the reported actions of divalent cations on the affinity of receptors for acetylcholine. The effects of surface potential on concentrations at active sites may play an important role in drug interactions.

Acetylcholine↗
PubMedDate not supplied

[French scientific contributions to anesthesia. Curares and the neuromuscular junction].

In France, a number of scientists from the fields of chemistry, physiology and surgery have been interested in anaesthesiology. Claude Bernard, who published in 1872 the most exhaustive studies on anaesthesia, was also interested from 1844 in drug curare. He created a methodology, studied pharmacology, including pharmacokinetics and demonstrated the specific action on motor nerves while muscle retained its irritability. It was however A. Vulpian who put forward the idea that curare does not affect the nerve itself but may act on a "linking substance" between nerve and muscle. In these times (1862), Rouget described the end apparatus at the nerve-muscle junction in a way which was finally accepted by German authors. Fifty years later, Couteaux achieved the microanatomic study of the end plate (1909). More recently (1972), Changeux and his team isolated the acetylcholine receptor from the electric organ of the torpedo fish.

Anesthesia↗
PubMed1991

Instrumental conditioning of skin potential responses in curarized cats: non specific effects of a punishment procedure.

This study evaluates the effects of a punishment paradigm upon electrodermal activity (EDA) in curarized cats. In ten experimental subjects, any skin potential response (SPR) exceeding threshold value was punished by an electric shock. Ten control subjects received an electric shock or an electric stimulation of the mesencephalic reticular formation unrelated to the EDA. The results show that: a) No significant modifications of EDA occurred in subjects characterized by low initial activity; b) The frequency of SPR significantly decreased in high activity subjects used both for the experiments and the controls. Therefore, this diminution, in experimental subjects, cannot be due to a learning process. Neither can it be related to level of curarization or to rate of artificial ventilation. It is suggested that this effect results from a non-specific cortical inhibitory mechanism acting on the reticular activating system. The results obtained in three decorticated cats submitted to a punishment procedure are in accordance with such an hypothesis. Consequently the existence of operant autonomic learning remains unproven.

Analysis of Variance↗
PubMed1982

[Influence of curare and methohexital-Na on the content of energy-rich phosphates and substrates of glycolysis in rat liver (author's transl)].

Our investigations demonstrate that 7',12'-dihydroxy-6,6'-dimethoxy-2,2,2',2'-tetramethyl-tubocuraranium dihydroxide (D-tubocurarine, Curarin-Asta), in the following briefly called curare, and methohexital sodium influence glycolysis and energy metabolism of rat liver cells. Within the first 5 min after i.v. application of curare we observed a decrease of ATP levels due to either increased energy demands during cellular metabolism or to a decrease of ATP production in the respiratory chain. This effect was followed by an activation of glycolysis as demonstrated by a decrease of cytoplasmic glycogen and an increase of glucose-6-phosphate. Simultaneously, cytoplasmic lactate levels were increased and redox potentials significantly shifted. The latter effect is caused by alterations in the lactate-pyruvate ratios. In contrast, methohexital sodium induced a significant increase of cellular ATP levels. The observed low lactate-pyruvate ratio and the changes in the adenylate system following methohexital sodium suggest that this drug reduces energy consumption during cellular metabolism.

Adenosine Diphosphate↗
PubMed1993

[Anesthesia before and after curare].

Before the advent of curare, muscular relaxation essential for upper abdominal and intrathoracic surgery adequate operating conditions, could only be provided by deep ether or cyclopropane anaesthesia. The required depth of anaesthesia frequently caused severe cardiovascular depression, metabolic and respiratory acidosis and alteration of kidney and liver function. Ether, and especially cyclopropane sensitized the heart to the development of arrhythmias and the danger of explosion was never far away. For fear of anaesthetic mortality essential, life saving operations were often abandoned in poor risk patients. The administration of anaesthesia was more an art, mastered by relatively few, than a science that could be taught to many. It is a tribute to the early masters of anaesthesiology that they were able to carry their patients through the dangers associated with the provision of anaesthesia for major surgical procedures, with relatively low morbidity and mortality. The introduction of curare into anaesthetic practice, by Griffith and Johnson, in 1942, caused profound changes in the efficacy and safety of anaesthesiology. It made possible the development of true balanced anaesthesia, and the elimination of the explosive inhalation anaesthetics and the profound metabolic disturbances associated with their use. The concept of "inoperability," due to severe pathology or extremes of age became obsolete. It would be hard to envisage how open heart, organ transplant and radical brain and cranio-facial surgery could have developed without muscle relaxants.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesiology↗
PubMed1975

Regional curare test in evaluation of ocular myasthenia.

In 7 of 14 patients with clinically restricted ocular myasthenia gravis, the regional curare test showed latent peripheral involvement. The test consisted of the intravenous administration of 0.2 mg d-tubocurarine into an ischemic arm followed by repetitive supramaximal percutaneous electrical stimulation of the median or ulnar nerves. This produced a decrease in the amplitude of the initial evoked potential and a decrement of greater than 10% in the amplitude of the succeeding three to five potentials at rates of 3, 5, or 15 stimuli/sec. Three patients underwent transcervical thymectomy with subsequent improvement in both electrical and clinical findings. Evaluation of all patients with ocular myasthenia gravis should include regional curare testing of clinically uninvolved peripheral nerves. Thymectomy should be considered for patients with abnormal results.

Adult↗