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G C Barbieri

Publications and source records attributed to G C Barbieri.

14 recordsLinked to original sources
PubMed1991

Functional activity mapping of the rat spinal cord during formalin-induced noxious stimulation.

The functional activity pattern in the cervical enlargement of the spinal cord (as expressed by changes in local glucose utilization) was investigated by the semi-quantitative [14C]2-deoxyglucose technique 2 min ("early" group) or 60 min ("late" group) after injection of a small amount of dilute formalin (0.06-0.08 ml, 5%) in a forepaw of unanesthetized, freely-moving rats. Control animals were either injected with an equivalent volume of saline or simply handled. In both formalin groups a tonic flexion of the injected limb was present during the experiments, while supraspinal-integrated behavior (such as licking the affected paw) was sharply reduced in the late group. A bilateral increase of metabolic activity indexes, more pronounced on the ipsilateral side, was found in the "early" formalin-injected animals. The highest increase over control values was found in the medial part of the superficial (laminae I-II) region of the ipsilateral dorsal horn. However, the [14C]2-deoxyglucose uptake was found to be elevated over the whole extent of the dorsal horns, as well as in the gray matter surrounding the central canal, anterior horns and ipsilateral dorsolateral funiculus. In a parallel group of experiments performed in pentobarbital-anesthetized rats metabolic increases in the early period after formalin injection were less pronounced; they were only found in the ipsilateral side of the cord. In the "late" formalin group the overall metabolic changes were less conspicuous. They were mainly observed in the side ipsilateral to the injection, the highest increase being found in the deep portion (laminae V-VI) of the dorsal horn. Therefore, the spatial distribution of functional activation elicited during prolonged noxious stimulation in the spinal cord gray matter of unanesthetized rats varies according to time and changes in animal behavior.

Animals↗
PubMed1987

Beta-lipotropin is the major component of the plasma opioid response to surgical stress in humans.

There is growing experimental evidence that beta-endorphin immunoreactivity is raised by surgical stress in patients undergoing general anesthesia. As the assay methods employed to date did not allow to fully discriminate between beta-endorphin and its immediate precursor, beta-lipotropin, we have investigated in the present study plasma levels of these two peptides by separating them by chromatography on plasma extracts prior to radioimmunoassay in eighteen surgical patients under general anesthesia and eight under spinal anesthesia. Beta-lipotropin, but not beta-endorphin, plasma levels were found to be significantly elevated during surgery in the general anesthesia group, while no change was found in either peptide concentration in the spinal one. Cortisol plasma levels also increased significantly 90 minutes after the beginning of surgery, when they were positively correlated to beta-lipotropin ones. Although the sampling time we adopted may have prevented us from detecting an early peak of beta-endorphin during the first 30 minutes of surgery, the major component of the pituitary opioid response to surgical stress appears to be related to beta-lipotropin. This is in agreement with results of experimental work on various kinds of stress in animals and humans and seems to rule out a role for plasma beta-endorphin in post-operative analgesia.

Adult↗
PubMed1987

Ketamine effects on local cerebral blood flow and metabolism in the rat.

The effects of an anesthetic dose (100 mg/kg) of ketamine, a phencyclidine derivative, on local rates of cerebral glucose utilization (LCGU) and CBF (LCBF) have been investigated by the quantitative [14C]2-deoxy-glucose and [14C]iodoantipyrine techniques in the unparalyzed, spontaneously breathing rat. In ketamine-injected animals, LCGU was significantly increased in some limbic structures and decreased in inferior colliculus, vestibular, and cerebellar nuclei. The degree and spatial distribution of drug-induced changes was similar for local blood flow rates, LCBF being increased in limbic regions and decreased in the inferior colliculus. Although Paco2 values were higher in anesthetized animals, the pattern of LCBF/LCGU ratios was not significantly affected by ketamine in the 36 brain regions examined in this study. So, at least in the rat and at the anesthetic level studied here, a net vasodilatory in vivo effect was not observed. These results support the hypothesis that CBF changes induced by the drug in animals and man are primarily related to the metabolic effects exerted by ketamine on cerebral structures.

Animals↗
PubMed1986

Opioid control of LH secretion in humans: menstrual cycle, menopause and aging reduce effect of naloxone but not of morphine.

A number of studies have been made on the role played by endogenous opioid peptides in the secretion of LH in humans. However no previous studies have compared the effects of the most potent pharmacological agonist and antagonist, morphine and naloxone, in the same subjects. The present study examined the acute effects of injections of morphine and naloxone on plasma LH levels in 30 healthy subjects (18 women and 12 men). Fertile women were subdivided into follicular (n = 6) and luteal (n = 6) phase groups; the remaining 6 were postmenopausal women. The 12 men were sub-divided in two groups of 6 subjects according to age (24-33 years, and over 60 years). There was a two day interval between injection studies in the same subjects. Morphine significantly decreased plasma LH levels in all groups examined (P less than 0.01). On the other hand, naloxone caused a significant increase in plasma LH levels in fertile women during the luteal phase of the cycle, but not during the follicular phase or in postmenopausal subjects, and in young but not in aged men (P less than 0.01). These results indicate that in humans there is a change in the activity of the opioids regulating LH secretion during the menstrual cycle, after menopause and in aged men and that these may be studied by the use of naloxone. The inability of naloxone under certain conditions to increase LH levels reflects the decreased activity of the endogenous system, while morphine, being active in all the subjects, seems to be less discriminative, at least in physiological conditions.

Adult↗
PubMed1985

[Description of a case of type E botulism in Italy].

The authors report the first documented italian case of type E botulism. The initial symptoms were typical permitting prompt diagnosis; the symptoms became severe and the patient had to be moved to intensive care. Biological tests on guinea-pigs showed the presence of type E botulin toxin in the tuna (stored in oil) which the patient had eaten 24 hours prior to admission. This tuna had been caught near the mediterranean coast of Spain several months earlier and canned at home. The authors emphasize that, even though this fish was imported, there is a danger that this intoxication could, in the future, be more widely observed.

Adult↗