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Biomedical subjects

A Galindo

Publications and source records attributed to A Galindo.

At least 55 records · Page 3Linked to original sources
PubMed1980

Lumbar epidural anaesthesia and sensory profiles in term pregnant patients.

Sensory profiles of lumbar epidural anaesthesia were studied in 57 patients, during active labour. The local anaesthetics used were chloroprocaine three per cent with and without epinephrine, chloroprocaine two per cent, bupivacaine 0.25 per cent and a mixture of chloroprocaine three per cent and bupivacaine 0.5 per cent. A common pattern of spread was found for all local anaesthetic solutions with the onset of the block affecting the dermatomes innervated by the thinnest nerve roots (T12L1). There was a percentage of failure to block the thickest nerve root (S1). Inguinal and suprapubic discomfort ("missing segment") occurred when S1 was not blocked. Under the conditions of this experiment, the addition of bupivacaine to chloroprocaine did not increase the duration of the blockade significantly.

Anesthesia, Epidural↗
PubMed1980

Mechanism of action of gallamine.

The mechanisms of action of gallamine on nerve terminals, cholinergic receptors, and the threshold for propagation of end-plate potentials to the muscle fiber were investigated in rat phrenic nerve-diaphragm preparations. Intracellular studies were made with glass microelectrodes to determine changes in end-plate potentials and miniature end-plate potentials produced by gallamine at concentrations between 10(-7) M to 10(-4) M. Gallamine excited and then depressed the release of transmitter from nerve terminals. This effect was clearly seen at rapid rate of stimulation and during studies of refractoriness using paried stimulation tests. Gallamine had no significant effects on the electrogenic properties of the excitable membranes of motor nerve terminals and muscle fibers; this compound depressed the response of postsynaptic receptors to action of acetylcholine as seen by the reduction in miniature end-plate potentials amplitude. Reduction in muscle twitch was caused solely by failure of propagation of end-plate potentials as muscle action potentials.

Animals↗
PubMed1980

Mixtures of local anesthetics: bupivacaine-chloroprocaine.

Experiments were performed in a rat sciatic nerve preparation to determine the characteristics of nerve blocks produced by a combination of commercially available solutions of bupivacaine and chloroprocaine. A mixture of equal parts of commercially available chloroprocaine 2% and bupivacaine 0.5% resulted in a nerve blockade with characteristics of a chloroprocaine block. Changing the pH value of this mixture from 3.60 to 5.56 changed these characteristics to a blockade resembling that produced by bupivacaine. It is concluded that the nerve blockades obtained by mixing commercially available solutions of local anesthetics are unpredictable and may depend on a number of factors which include not only the types of drugs but the pH of the mixture.

Action Potentials↗
PubMed1975

Quality of spinal extradural anaesthesia: the influence of spinal nerve root diameter.

Profiles on the progress of spinal extradural anaesthesia were made in 246 patients using various concentrations of lignocaine, bupivacaine and etidocaine. The advance of analgesia through the different dermatomes showed a consistent and orderly spread on the upper lumbar and thoracic segments. This spread was irregular through the lower lumbar and upper sacral segments. The first sacral segment was especially difficult to block with an overall failure rate of 17.53% with presently available concentrations of various local anaesthetics. This failure was abolished with the use of etidocaine 1.5%. The presence of a delay or failure at the level of L5-S2 is probably related to the larger diameter of these nerve roots as ascertained from measurements in 11 cadavers.

Acetanilides↗
PubMed1975

Neuromuscular transmission in a mammalian preparation during exposure to enflurane.

The effects of enflurane on motor nerve terminals and muscle endplates were studied in the rat phrenic nerve-diaphragm preparation using standard microelectrode recording techniques. Muscle endplate interaction with enflurane was suggested by depression of the amplitude of miniature endplate potentials (MEPP's) without change in frequency, increased duration of MEPP's and endplate potentials (EPP's) increased threshold for generation of muscle action potentials, and inhibition of the endplate depolarization induced by succinylcholine. Evidence of nerve terminal effects of enflurane was limited to a greater relative decline of EPP amplitude during tetanus, indicative of failure to maintain transmitter output at rapid rates of stimulation. It is concluded that the depressant effect of enflurane on indirectly elicited muscle twitch is primarily due to an impairment of the action of muscle endplate on adjacent membrane; however, the relative importance of prejunctional depression, seen only during rapid nerve stimulation, cannot be assessed from the present data.

Action Potentials↗
PubMed1972

Curare and pancuronium compared: effects on previously undepressed mammalian myoneural junctions.

Curare and pancuronium have multiple effects on previously undepressed rat diaphragm; these include depression of transmitter output and prolongation of the refractory period of prejunctional structures. The effect of curare on motor nerve terminals is greater than that of pancuronium. Both drugs depress postjunctional receptors; but curare, in addition, raises the threshold for the generation of muscle action potentials. In addition, these results raise questions about the validity of statistical methods used to calculate transmitter output.

Action Potentials↗