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E Balzamo

Publications and source records attributed to E Balzamo.

At least 37 records · Page 2Linked to original sources
PubMed1991

Effects of breathing dense gas mixtures on cardiovascular function and EEG rhythms.

Gas mixtures containing oxygen and nitrogen or dense inert gases (sulfur hexafluoride, SF6, or argon, Ar) were inhaled by anaesthetized, artificially ventilated rabbits and cats. SF6 and Ar were compared to nitrous oxide (N2O), a dense inert gas well known for its anaesthetic properties. Concentrations in these gases were 50% (SF6) and 60% (Ar or N2O). In cats, there was a significant increase in total lung resistance with SF6 or Ar associated with a slight but significant drop in arterial blood pressure and heart rate (-5% and -10% with SF6 and Ar, respectively), with no change in electrocardiogram activity. N2O induced in some cats a slower electroencephalographic (EEG) pattern constituted by delta waves of higher amplitude, whereas neither SF6 nor Ar changed the EEG rhythms in this species. In the rabbits, the unsteadiness of the EEG rhythms did not make it possible to assess the cortical effects observed with SF6 or N2O.

Administration, Inhalation↗
PubMed1990

Pulmonary vagal sensory afferents and spontaneous EEG rhythms in the cat sensorimotor cortex.

Interactions between vagal afferent fibres and spontaneous electroencephalographic (EEG) activity, recorded on the sensorimotor cortex of the cat, were studied during the mechanical activation of pulmonary afferents. The interactions were compared to the cortical effects of the electrical stimulation of all vagal fibers or to the chemical activation of unmyelinated vagal afferents (C-fibers) by phenyldiguanide. The present study was performed on anesthetized cats, artificially ventilated with open chest. Over 60 locations were explored on the posterior sigmoid gyrus. Repetitive electrical stimulation (30 Hz, 0.8 ms shock duration) of the contralateral cervical vagus nerve or of both nerves induced within less than 5 s changes in the pattern and periodicity of EEG spindles, associated with depressed background rhythms or rhythmic EEG activities. Cortical responses were also observed after i.v. injection of phenyldiguanide. Changes in activity of pulmonary stretch receptors by lung hyperinflation or suppression of phasic lung inflations ('stop pump') had no effect on the EEG rhythms. On the other hand, expiratory threshold loading or passive hyperdeflation of the lungs elicited EEG changes similar to those obtained by electrical stimulation of all vagal fibers. After bilateral vagotomy, all these responses disappeared or were delayed. The present observations strongly suggest that sensory information carried by thin vagal fibers greatly influences cortical rhythms in the cat sensorimotor cortex.

Animals↗
PubMed1989

Vagal afferents and EEG rhythms in the Sl area in anesthetized cats: similarities between responses to electrical and chemical (phenyldiguanide) stimulations.

In anesthetized, artificially ventilated cats with open chest, bilateral stimulation of all afferent vagal fibres (pulse duration: 800 microseconds, 30 Hz, train duration 30 to 40 s) produced marked changes in the spontaneous EEG activities in the primary somatosensory cortex (Sl area). They were characterized by depressed background rhythms, with a tendency to desynchronization, decreased amplitude and number of spindles, with altered pattern, and/or evoked sustained fast rhythmic activities. These effects occurred within 1 to 5 sec during vagal stimulation. On the contrary, the EEG response was weaker or absent when only myelinated vagal afferents were stimulated (100 microseconds). I.v. injection of phenyldiguanide (PDG), used for stimulation of unmyelinated vagal sensory fibres and mainly of pulmonary afferents, induced EEG changes within the first 30 s, similar to those observed during electrical vagal stimulation. These EEG responses were unrelated to the induced hypotension. Cervical bivagotomy produced persistent changes in EEG activity, with enhancement of the magnitude, duration and number of spindles, which resembled the delayed effects induced by PDG. The present results obtained with three test agents (electrical or chemical vagal stimulation and bivagotomy) demonstrated that, in cats, vagal afferent information interacted with the spontaneous EEG rhythms in the Sl area.

Afferent Pathways↗
PubMed1982

[Facilitation of a state of wakefulness by semi-chronic treatment with sulbutiamin (Arcalion) in Macaca mulatta].

Cortical electroencephalographic (EEG) activities and nycthemeral states of vigilance organization were studied in 6 adult rhesus monkeys during subchronic administration (10 days) of Sulbutiamin, a synthesized derivative of thiamine (300 mg/kg/day). Sulbutiamin induced the following modifications: (1) In the EEG activities: increase in occurrence of fast rhythms (over 28 c/sec) during waking and also during slow sleep (SS) in which their amplitude doubled. SS spindles increased in number and amplitude. (2) In vigilance organization: waking was enhanced all along the 24 h recording and SS was reorganized (particularly at night), mostly light sleep: large decrease in stage 2 duration, increase in stage 1. REM sleep duration remained stable. These changes, occurring at around day 5 of the treatment, were more pronounced on day 10 and disappeared 2-5 days after withdrawal. This study demonstrated the clear action of Sulbutiamin upon the mechanisms regulating waking and light sleep.

Animals↗
PubMed1981

[Peculiar and random activity in Macaca: delta rhythm at the vertex].

Despite the fact that waking and sleeping EEG activities are well known in cercopithecinae, a striking random activity was noted in 3 macaque species: M. mulatta, M. fascicularis, M. nemestrina. It occurred in bursts of monophasic slow waves (250-400 msec) at 3/sec (2.5-4/sec, according to the moment and the individual at 50-480 microV amplitude, with a waxing and waning aspect. The duration was 2-24 sec. It predominated along the midline, in the precentral and supplementary motor areas; hence its name, the delta vertex rhythm. It occurred either isolated or several times within the same REM or waking episode. In some monkeys it was more or less frequent on different recording nights; however, in other monkeys it could be totally absent. Its mean total duration, for a 12 h recording, was 0.45% for M. mulatta and 0.065% for M. fascicularis. No significant correlations were found between its occurrence and the age, sex, the moment of occurrence of eye movements and sawtooth waves.

Animals↗
PubMed1981

[Observation of a photosensitive syndrome in Macaca nemestrina (author's transl)].

Out of a group of 12 M. nemestrina (originating from Malaysia), 9 adults had shown clinical signs induced by ILS at 25 c/sec. Six of them (3 males, 3 females) were very photosensitive; however, only 2 presented eyelid and/or head jerks after the end of ILS (level 4), but never a generalized seizure. Tactile periorbital stimuli favoured myoclonus. In all but the two of level 4, the intensity of clinical signs varied from one day to the next. In all implanted adult macaques, spontaneous paroxysmal EEG activities were seen during slow sleep in mostly anterior areas, but also during waking and REM sleep in some of them; however, their occurrence depended upon the individual and were not in all cases related to their level of photosensitivity. During ILS, paroxysmal discharges (spikes and waves and/or polyspikes and waves), isolated or in bursts at 3-4/sec were bilateral and symmetrical. They started in fronto-rolandic regions, then became generalized. This observation constitutes a new fact since the discovery, in 1966, of the photomyoclonic syndrome of Papio papio, Macaca nemestrina being another species of subhuman primates with a marked predisposition to photosensitive epilepsy.

Aging↗
PubMed1981

[Night sleep study in chronic psychotics under long term flupenthixol treatment (author's transl)].

Ten chronic psychotics under long term Flupentixol treatment were recorded by series of 3 consecutive nights (8 h.). Only minor sleep organization disturbances were found: decrease of total sleep time (stages 1, 3, 4) and lengthening of sleep onset latency. Total REM duration remained close related to control one. However, intermediary phases were frequent and over 20 min. by night. The "first night effect" was to the second but only slow sleep was implicated.

Adult↗
PubMed1980

[States of wakefulness and ponto-geniculo-cortical activities (PGC) in Papio anubis (author's transl)].

EEG, sleep-waking organization and phasic sleep activities (PGC) were studied in 6 adult female Papio anubis with chronically implanted electrodes and partially constrained. Papio anubis shows a well characterized sleep (besides an individuality peculiar to each baboon): short sleep latency (18 +/- 14 min), very brief REM latency (5 +/- 5 min), stable stage 1 (86 +/- 11 min), REM duration with little variation (70 +/- 15 min) and abundant deep sleep (stage 4 = 79 +/- 44 min). Geniculate spikes, in general biphasic, occur in great number in this species: 34,778 +/- 7355 per night (44.6% of them in REM). The frequency of spike discharges per minute in REM reaches a mean of 218 +/- 10. In true slow sleep (SS 1), 4--5 spikes per group prevail; in slow sleep followed by a REM episode (SS 2), 6--10 spikes per group are the most numerous. REM is characterized by groups of 6--10 or more spikes. Several specific features are seen: (1) alternation and/or asymmetry of the bursts from the 2 lateral geniculate (LG) nuclei during SS 2 and REM, tendency towards symmetry in SS 1; (2) inversion of spike polarity in the lowest LG layers; (3) variation in spike form from one instant to another and from one LG to the other; (4) presence of spikes in the optic tract. At the cortical level, PGC phasic activities resemble the 'saw tooth waves' described in man. The PGC activities of various primates, and particularly of Papio anubis, seem, by their complexity, to reflect a more elaborated evolution of this particular phenomenon of sleep and differ from those of cat. The monkey lends itself, hence, as a better model for any extrapolation to man. Finally these results raise the question of species within a single genus.

Animals↗
PubMed1980

Experimental kuru in the rhesus monkey. A clinical study.

Serial neurologic examinations of six rhesus monkeys inoculated with a strain of kuru revealed complex clinical signs falling into two distinct syndromes. Experimental kuru in the rhesus monkey is different from the disease in man and to a lesser extent in the chimpanzee. Two factors are proposed to account for these observations: modification of the strain, and specific host characteristics.

Animals↗
PubMed1980

[Night sleep study in acute and chronic psychosis (author's transl)].

A group of 22 psychotics (19 schizophrenics) was recorded in acute and/or chronic phase by series of 3 consecutive nights. Our main purposes were to study correlations between subgroups and sleep patterns and to follow the clinical evolution of these patients in looking at the quantitative and/or qualitative modifications of the various sleep states. Schizoaffective psychotics showed a lack of the "first night effect". The patients recorded in acute and in remission phases differ from unmedicated normal subjects: the former had less deep sleep and more "intermediate phases": the later presented an increase, sometimes very high, of REM total duration. Finally, within each subgroup, the analysis of individuals pointed out, for some of them, an evolution opposite to the general tendency.

Adult↗
PubMed1978

Experimental kuru in the rhesus monkey: a study of EEG modifications in the waking state and during sleep.

EEG patterns recorded in the waking state and during sleep were studied in 6 rhesus monkeys inoculated with a strain of Kuru previously passaged in rhesus monkey (ENAGE strain, rhesus L6 56). The onset of the disease was confirmed by the appearance of various clinical signs in 4 monkeys 15 months after inoculation. At the 16th month, the first EEG modifications appeared during sleep, which became lighter. The waking EEG was abnormal during the mature phase of the disease; it was characterized by slow anomalies and scattered spikes. The sleep EEG still presented 3 stages of Slow Wave Sleep which, however, were totally unlike the physiological stages. REM sleep rapidly disappeared, as did the cyclic organization pattern. Irritative phenomena became very significant and, in particular, very frequent 'tonic seizures' were observed. Experimental Kuru thus appears, in the rhesus monkey, as an epileptogenic encephalopathy, which is differentiated from both the human disease and the experimental disease in the chimpanzee.

Animals↗
PubMed1978

Appearance of EEG changes reminiscent of a secondary generalized epilepsy in a rhesus monkey inoculated with a strain of kuru.

In a group of rhesus monkeys (Macaca mulatta) inoculated intracerebrally and intravenously with a strain (Enage strain rhesus L6 56) of kuru already passaged in rhesus monkeys, 1 monkey presented the typical EEG pattern of epileptogenic encephalopathy reminiscent of the Lennox-Gastaut syndrome. This observation provides no direct evidence for the viral origin of epilepsies of this type. It does, however, show that it is possible to induce an epileptogenic encephalopathy by an unconventional infectious agent.

Animals↗
PubMed1977

[Sleep changes induced by chronic administration of S. 1694 (Survector) (author's transl)].

Five adult Macaca mulatta were studied during chronic administration (24 days) of S. 1694 (10 mg/kg, i.m.). This substance induced a significant increase of the first awakening (delaying sleep onset) and an enhancement of the duration of REM and stage 4 sleep. After withdrawal, the waking effect desappeared, but the increase in stage 4 sleep was maintained for one week and REM enhancement kept rising for 15 days. This observation of long-term action underlined the validity of drug experiments in chronic treatment: S. 1694 might set a new type of monoaminergic systems regulation.

Animals↗
PubMed1977

Nonhuman primates: laboratory animals of choice for neurophysiologic studies of sleep.

A systematic study was made of several nonhuman primates to learn more about their relative usefulness for studies of sleep. Species studied included the Guinea baboon (Papio papio), Kenya or yellow baboon (P cynocephalus), olive baboon (P anubis), sacred baboon (P hamadryas), vervet monkey (Cercopithecus aethiops), rhesus monkey (Macaca mulatta), bonnet monkey (M radiata), crab-eating monkey (M fascicularis), patas monkey (Erythrocebus patas), chimpanzee (Pan troglodytes), mongoose lemur (Lemur mongoz), black lemur (Lemur macaco fulvus), and bushbaby (Galago senegalensis). Comparisons were made of electroencephalographic activity, states of vigilance, and responses to sleep-waking drugs. The results showed that there were major similarities among the genera studied as well as individual intrageneric and intraspecies differences. It was concluded that the chimpanzee, olive baboon, and rhesus monkey were the best species for comparative studies, and that the rhesus monkey was the best single model because of its well defined sleep organization and ease of handling and housing.

5-Hydroxytryptophan↗
PubMed1975

[Evolution of visual evoked responses during various states of vigilance in Papio papio (author's transl)].

Averaged evoked responses (AER) to light flashes were recorded in baboons (Papio papio) during wakefulness, slow-wave sleep and rapid eye movement (REM) periods, at the visual cortex, retrocalcarine sulcus, optic tract (OT), lateral geniculate (LG) and pulvinar. Waking AERs were composed: in the OT, of a negative, low amplitude wave at 13.3 msec (I), a high amplitude wave at 34.8 msec (II), a negative wave at 72 msec (III) and a late component at 151 msec; in the LG, a small positive wave (II) with a peak latency of 40 msec, a high amplitude negative wave (III) with a latency of 70 msec and a late component; in the pulvinar of two low amplitude short latency waves (I and II), respectively negative and positive at 25 msec and 40 msec, then a high amplitude negative wave (III) at 75 msec and a late component; in the retrocalcarine sulcus 3 positive waves (I, II and III) were recorded at 25, 45 and 100 msec and a late component; in the visual cortex, 3 low amplitude negative waves (II, III and IV at 40, 50 and 54 msec, then a positive wave at 80 msec and some late components. In slow-wave sleep, AERs did not change in the OT, but in the LG and pulvinar, they showed an increase in the amplitude of wave II from stage 1 to stage 3. At the cortical level, early waves (II for the retrocalcarine sulcus, II and IV for the visual cortex) presented a marked increase in amplitude during stages 2 and 3, but only a slight increase for stage 1. Peak latency increase of each wave in cortical and subcortical AERs was seen during slow-wave sleep. REM AERs resembled, in amplitude and peak latency, those recorded in the LG and pulvinar during wakefulness; in the visual cortex and retrocalcarine sulcus, they were similar to those obtained during wakefulness and stage 1. In conclusion, a different evoked response was found between visual cortex and deep structures (except for the OT): firstly, during slow-wave sleep (the AERs showed a difference for stage 1 between the visual cortex or the retrocalcarine sulcus and the LG or the pulvinar), secondly, in REM (on the cortex, REM AERs looked like wakefulness and stage 1 responses); on the contrary, in the LG and pulvinar, REM AERs were similar only to those recorded during waking. Finally, it can be said that for Papio papio the differentiation and structural responses between the various stages of sleep (particularly light sleep and REM) were greater in the cortex than in the thalamic structures.

Animals↗
PubMed1975

The sleep of the baboon, Papio papio, under natural conditions and in the laboratory.

The sleep pattern of sixteen baboons (Papio papio) was studied under two very different conditions: (1) in a laboratory at Marseilles, the monkey being immobilized in a restraining chair in a soundproof cubicle; (2) in an African reserve, the monkey being housed in a large cage placed in its natural environment. Some very marked differences emerged. Sleep in the laboratory was longer (by 24 min) and richer in stage 3 and paradoxical sleep. In Africa, however, the sleep showed much more stage 1, was more fragmented and stages 2 and 3 and paradoxical sleep episodes were of shorter duration. Records made in Africa indicate that sleep is independent of slight environmental changes (day length, brightness of the moon, variations in temperature, calls of predators). But the comparison of the two series of results reveals the reorganization which occurs when the monkey is exposed to such different conditions. This adaptation to the environment affects, unequally, the various slow sleep stages and paradoxical sleep. In fact, the major modifications occur in stages 1 and 3 of slow sleep and in paradoxical sleep, while stage 2 appears to constitute the stable, unmodifiable nucleus of sleep.

Animals↗