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Biomedical subjects

G Carli

Publications and source records attributed to G Carli.

At least 55 records · Page 3Linked to original sources
PubMed1989

Changes in electromyographically recorded human monosynaptic reflex in relation to hypnotic susceptibility and hypnosis.

The aim of the present experiment was to study how hypnotic susceptibility and hypnosis affect motoneuron excitability. In a first trial, human subjects were selected according to their hypnotic susceptibility. In a second trial, the Hoffmann (H) reflex amplitude of the soleus muscle was studied in 3 groups: (1) highly susceptible subjects during hypnosis with standardized suggestions of simple relaxation, anesthesia, analgesia and paralysis (group I), (2) highly susceptible subjects (group II), and (3) non-susceptible subjects (group III) during long-lasting control conditions. Surface Ag/AgCl electrodes were used to stimulate the posterior tibial nerve using a constant current stimulator and to record the soleus EMG. Analysis of variance was performed on the data. The linear correlation coefficient within groups was evaluated. The H reflex amplitude decreased significantly during the recording session in groups I and II and there was no change in group III. In group I the effect of different suggestions could not be distinguished from the effect of hypnotic relaxation. The decrements in H amplitude did not differ between groups I and II, suggesting that the effect was related to personality traits rather than hypnotic induction.

Electric Stimulation↗
PubMed1988

Tonic pain and social behavior in male rabbits.

The 4 subjects each of 6 all-male colonies of rabbits studied in a seminatural setting rapidly established a dominance hierarchy. A combination of behavioral parameters obtained in two experimental situations was used to assign each individual a quantitative score of dominance. The situations were: 'intermale' activity between the residents and 'intruder test', i.e. the reactivity to the introduction of a male conspecific. Fifteen days later, tonic pain (formalin injection) was inflicted on the dominant, and the short-term effects on the treated animal and the social behavior of the group were studied. Licking of the injected foot was used to measure the intensity of pain; this reached a peak 4-8 h after injection and persisted with decreasing intensity into the second day. The painful condition resulted in a general dramatic decrease in motor and social activity including aggressive elements during the intruder test. A positive correlation was found between reduction in motor activity and pain intensity. However, the treated animals did not develop submissive behavior, while the untreated subordinates persisted in their prevalence of submissive over aggressive elements. This contributed to maintain in most cases the behavioral asymmetry of the agonistic activity of the different ranking animals. The possible mechanisms of the observed behavioral modifications are discussed.

Agonistic Behavior↗
PubMed1988

Response of hip joint afferent fibers to pressure and vibration in the cat.

Mechanical properties of 33 slowly adapting and 8 quickly adapting capsule receptors of the hip joint were investigated. All the slowly adapting receptors identified were of a limited range, discharging only when the femur was rotated to its limit of movement. They behaved as single-spot high-threshold pressure receptors as shown by the von Frey's hairs. In addition they showed a low sensitivity to vibratory stimuli applied perpendicularly to their receptive field. Only 14 out of 33 units were found to discharge following vibration; 11 could be driven 1:1 at different frequencies. There was a general trend to be entrained at lower amplitudes for higher frequencies of vibration. A positive correlation between the pressure threshold and both activation angle and vibration threshold was found. The mechanical properties of all the quickly adapting capsule receptors were found to be similar to those described in other tissues. Finally, unlike joint receptors, slowly adapting muscle afferents travelling in the same hip articular nerve were highly sensitive to pressure and vibratory stimuli.

Action Potentials↗
PubMed1986

Hormonal and metabolic effects following a football match.

Hormonal and metabolic parameters were studied for two teams after a football match. Blood samples were collected before the start, at half-time, at the end, and 45 and 90 min after the end of the game. In the first team, ACTH, cortisol, and lactate levels increased significantly during the whole match to resume basal levels in the fourth sample (45 min after the end of play). HGH, prolactin, and blood glucose were found to be increased only at half-time. The second team had an intense and long warm-up period before the match and the lactate concentrations were already elevated in the first sample. All the other parameters, except ACTH and glucose, displayed a pattern similar to that of the first team. The differences in the time courses of the hormonal and metabolic values are discussed.

Adrenocorticotropic Hormone↗
PubMed1985

Androgen levels following a football match.

In 18 trained football players, blood samples were collected before a football match, at half-time, at the end, and 45 and 90 min after the end of the match. The testosterone (T) level showed a decrease in the rest period. Dihydrotestosterone (DHT) increased during the match, but returned to initial levels in the last samples. The T/DHT ratio decreased, reached the minimal value at the end of the exercise, and returned to basal levels in the rest period. Cortisol and androstenedione levels increased during the match, but returned to control levels 45 and 90 min after the end of the match, respectively. It is suggested that during this type of exercise anabolic and catabolic hormones may be simultaneously activated.

Adult↗
PubMed1985

Reference equations for the single-breath diffusing capacity. A cross-sectional analysis and effect of body size and age.

A longitudinal study was implemented in an unpolluted rural area of northern Italy (near Venice), before the start of the operation of a large oil-burning thermoelectric power plant, in order to investigate the effects of the future exposure to air pollution and to elucidate the natural history of obstructive airways diseases. During the first cross-sectional survey, a sample of the general population (n=3,300, 8 to 64 yr of age) performed several lung function tests, and information on risk factors and on the presence of respiratory symptoms were obtained by a standardized questionnaire. There were 712 subjects who were classified as normal on the basis of rigid criteria and who were able to perform satisfactorily a single-breath CO diffusing capacity (DLCOsb) test. The DLCOsb values showed an increase with height and age early in life and a later decrease with age. Two age groups were selected to determine an age at which DLCOsb stopped increasing and began to decline. Reference equations were computed (using age and height) in these 2 different age groups in each of the sexes. Similar equations were calculated for the total lung capacity derived from single-breath helium dilution measurements. The DLCOsb values in this study were higher than reported by other investigators. The method of selection of the study population, the strict criteria for normal, as well as technical, differences probably explain this finding. Reference equations for diffusing capacity corrected to lung volume (DL/VA) were computed only for adults (much greater than 20) in both sexes, because age and height coefficients in young subjects were insignificant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Changes in brain serotonin and 5-hydroxyindolacetic acid levels in the rabbit following tonic immobility.

The effect of tonic immobility on serotonin (5-hydroxytryptamine, 5-HT) and on 5- hydroxyindolacetic acid (5-HIAA) levels in different brain areas has been investigated, following two different schedules of treatment. The massed treatment consisted of a series of consecutive trials up to 15 min, the spaced treatment in 4 series of trials within 24 hours. Massed treatment produced a decrease in 5-HT in the mesencephalon and of 5-HIAA in the pons-medullary area, but similar changes were also elicited in animals treated with the procedure of induction not followed by immobility. The spaced treatment, which resulted in a potentiation of the immobility duration, i.e., sensitization, produced a reduction of 5-HT levels in the mesencephalon and of 5-HT turnover in the striatum. The procedure of the induction per se acts preferentially on 5-HIAA by increasing its levels. In the striatum, which appears selectively responsive to the spaced treatment of immobility, a negative correlation has been found between serotonin levels and immobility duration. Results suggest that elicitation of tonic immobility is associated with reduced levels of 5-HT in the brain.

Animals↗
PubMed1984

Hippocampal electrical activity and behavior in the presence of novel environmental stimuli in rabbits.

Male rabbits have been used in a simultaneous study of their behavioral and neural activity in different experimental situations related to attention and emotionality. The electrical activity of the dorsal hippocampus and frontal cortex was recorded in the following experimental situations: Neutral Environment (response to a novel environment); Object (response to a novel stimulus); Stuffed sparrow hawk; and live cat. Results show that behavioral and electrical responses depend upon: (a) the nature of the stimulus; and (b) whether or not the stimulus is moving. As for the immobile stimuli, the stuffed animal presentation significantly reduced both behavioral activity and percentage and frequency of rhythmic slow activity (RSA); prolonged periods of ECoG synchronization were also recorded. The introduction of the live cat greatly increased the percentage and frequency of RSA, especially when the cat was looking at the rabbit. The experimental situations caused differences in the distribution of RSA frequencies as well. The percentage of high RSA frequencies (greater than 6.5 Hz during immobility; greater than 7.2 Hz during movement) recorded in response to the immobile stimuli was negatively correlated to the amount of RSA. Results are discussed in the light of attentional and emotional theories.

Animals↗
PubMed1984

Physiological characteristics of pressure immobility. Effects of morphine, naloxone and pain.

This study is an attempt to detect the most important modifications of physiological parameters occurring during pressure immobility in rabbits and to compare them with those recorded during animal hypnosis. Like the latter, pressure immobility is characterized by the development of high voltage slow waves in the EEG, reduction in frequency and amount of rhythmic slow activity in the hippocampus (RSA) and depression of spinal polysynaptic reflexes. Systolic and diastolic blood pressures are not modified. Duration of two types of immobility is positively correlated within individuals. Treatment by a single dose of morphine (1 mg/kg) potentiates the duration and this effect is antagonized by naloxone (1 mg/kg). Repeated morphine injection up to tolerance reduces duration. Pressure immobility may also be produced under persistent nociceptive stimulation and is characterized by the development of high voltage slow waves in the EEG, as is typical in the absence of pain. Naloxone, (5 mg/kg) injected in a condition of persistent noxious stimulation, reduces immobility duration. In contrast to animal hypnosis, the duration of pressure immobility is neither potentiated by pain nor reduced by naloxone (1,5 or 20 mg/kg). It is suggested that the two immobilities are controlled by several mechanisms, some similar, some different.

Animals↗
PubMed1982

Hippocampal rhythmic slow activity (RSA) during animal hypnosis in the rabbit.

Hippocampal electrical activity has been studied in 12 unanaesthetized, unrestrained rabbits during hypnosis and spontaneous activity in the experimental cage, before and among hypnosis trials. Quantitative analyses showed that rhythmic slow activity (RSA) occurred during exploratory movements (mean frequency 7.2 Hz) and also during spontaneous immobility, but a lower percentage and frequency (6.5 Hz). RSA was always present during the induction of hypnosis, but its frequency decreased and disappeared at the beginning of immobility, when it was replaced by a large amplitude irregular activity (LIA). During hypnosis RSA occurred in short periods, at low frequency (5.7 Hz). During the initial part of hypnosis, the lowest percentage of RSA was recorded. In the sec ond and third part, RSA increased in number of episodes, total amount, duration of a single episode and mean frequency. RSA of higher frequency occurred at the end of hypnosis, preceding righting movements. The relationships between hippocampal RSA and animal hypnosis are discussed.

Animals↗
PubMed1982

Animal hypnosis: an attempt to reach a definition.

Animal hypnosis is a prolonged immobility response which may be defined according to several physiological parameters. In the rabbit, EEG, hyppocampal rhythmic activity, spinal reflexes and local cerebral glucose utilization are modified during this condition. The duration of the response is affected by persistent nociceptive stimuli. Corticosterone plasma levels are correlated with individual susceptibility and elevated when habituation to hypnosis occurs. Testosterone metabolism in the hypothalamus is found decreased after a single trial and increased following repeated trials. The possible importance of these modifications is discussed.

Animals↗
PubMed1981

Depression of cerebral glucose utilization during animal hypnosis in the rabbit.

The rates of local cerebral glucose utilization have been measured in normal conscious and hypnotized rabbits by the [14C]deoxyglucose method. In control rabbits the rates vary widely throughout the brain, with the values in gray matter broadly distributed around an average which is about 3 times greater than that of white matter. The higher values area in structures of auditory system (superior olive, inferior colliculus, auditory cortex). Animal hypnosis reduces the rates of glucose utilization in all structures of the rabbit brain, particularly in the caudate nucleus, putamen and sensory and motor cortices.

Animals↗
PubMed1981

Neuroendocrine changes following habituation of animal hypnosis in male rabbits.

Neuroendocrine changes have been studied in male rabbits during daily repeated inductions of animal hypnosis. All the animals attained the habituation but after different times, showing a different individual sensitivity to the treatment. Once habituation was reached, further treatment did not elicit any recovery. Corticosterone plasma levels gradually increased during treatment, reached a peak at habituation and did not change afterwards. Because corticosterone was not modified after habituation was established, despite further manipulation of the animals, it can be assumed that the increase of corticosterone is due to hypnosis. ACTH did not follow the same pattern of variation as corticosterone: an increase was found at habituation, but this was not statistically significant. Estradiol decreased and the testosterone/estradiol (T/E) ratio increased on the final day with respect to Day 1, whereas testosterone plasma levels were not modified by the treatment. However, there was a general increase of testosterone metabolites (dihydrotestosterone, estradiol) studied in vitro in the anterior hypothalamus of rabbits sacrificed at the end of the treatment. Thus the different responsiveness associated with repeated induction of animal hypnosis changes basal levels of ACTH, steroid hormones and central testosterone metabolism.

Adrenocorticotropic Hormone↗