Analysis of the human a-wave ERG component.

The a-wave is one of the main issues of research in the field of ocular electrophysiology, since it is strictly connected with early photoreceptoral activities. The present study proposes mathematical methods that analyse this component in human subjects, and supports experimental evidence relating to possible correlations among the responses of photoreceptoral units under a light stimulus. The investigation is organized in two parts: the first part concerns the onset and the initial slope, up to the first minimum (about 10-15 ms), the second part deals with the main portion of the wave, up to about 30 ms. In both cases, the a-waves, recorded at various levels of luminance, have been fitted with a set of appropriate functions representing possible models of physiological behaviour which would take place in the early stages of phototransduction. The statistical nature of the underlying processes is also discussed. The results indicate that correlations occur in the early stages, whereas random processes are set up later.

[Effects of betamethasone on neuromuscular blockade induced by vecuronium in continuous infusion]. / Effetti del betametasone sul blocco neuromuscolare indotto con vecuronium in infusione continua.

The aim of the study was to determine a possible interaction between a corticosteroid (betamethasone) and vecuronium, a nondepolarizing muscle relaxant. The authors studied 20 patients, ASA I-II, aged 20-54, both sexes, scheduled for abdominal surgery. Mechanomyographic and clinical evaluation by single twitch and TOF stimulation of the ulnar nerve at the wrist and measurement of the concomitant abductor pollicis muscle was applied. The onset time of vecuronium after a single bolus dose of 0.08 mg/kg, duration of action to 10% single twitch recovery, duration of continuous infusion of 0.4-0.5 micrograms/kg/min of vecuronium started at 10% single twitch recovery, and the effects of 0.1 mg/kg betamethasone administration 10 min after continuous infusion were evaluated. The recovery rate of vecuronium after stopping infusion at 10% recovery was also evaluated. Corticosteroids may interact with non-depolarizing muscle relaxants both in prejunctional and postjunctional acetylcholine receptors by several mechanisms of action.

[Psycho-functional changes in attention and learning under the action of L-acetylcarnitine in 17 young subjects. A pilot study of its use in mental deterioration]. / Cambiamenti psicofunzionali dello stato di vigilanza e dell'apprendimento sotto l'azione della L-acetilcarnitina in 17 giovani soggetti. Studio pilota per l'impiego nel decadimento mentale.

The aim of the study was the investigation of the ability of L-acetylcarnitine (Acn; 1.5 g daily oral route for 1 month) to enhance some performances requiring a high level of attention and reflex velocity. The sample includes 17 healthy subjects, 8 males and 9 females, 22 to 27 years old; 10 of the subjects practice sports at agonistic level, while 7 have a sedentary life style. Reflexes have been measured, baseline and after 17 and 30 days of Acn administration, through a purposely constructed reflex-meter able to determine the latency (csec) of the reaction to an auditory stimulus. The ability as well as the time of learning was determined, before and after treatment, as the time and the number of errors to get out of the maze of a videogame (the test was also carried out by an untreated control group). Acn seems to induce an enhancement of reflex velocity, with complete annulment of the difference between the dominant and the opposite hand, as well as a significant reduction (3 to 4 times superior to controls) of both the errors and the time with the maze test.

[The effects of succinylcholine on heart rate and rhythm in infants]. / Studi sugli effetti della succinilcolina sulla frequenza e sul ritmo cardiaco del lattante.

The authors examined the possible variations of cardiac activity in 91 infants aged between a few days and six months in order to study the changes following administration of succinylcholine during general anaesthesia. No variations in rhythm and/or heart rate occurred, not even in those children to whom atropine had not been injected intravenously before succinylcholine.