Search PubMed⌕ Search

Biomedical subjects

R Guieu

Publications and source records attributed to R Guieu.

At least 37 records · Page 2Linked to original sources
PubMed1995

beta-Endorphin and blood pressure in multiple trauma victims.

In addition to pain and stress, endogenous opiates and in particular beta-endorphin could be involved in the modulation of cardiovascular parameters. Several studies have thus shown increases in plasma beta-endorphin levels in the course of septic or hypovolemic shock. Our study involving 44 multiple trauma patients indicates that even in the absence of any hemodynamic disorders, there is a correlation between systolic blood pressure and plasma beta-endorphins. These results argue in favor of the existence of feedback between systolic blood pressure and plasma beta-endorphins.

Adult↗
PubMed1994

The use of HPLC to evaluate the variations of blood coronary adenosine levels during percutaneous transluminal angioplasty.

Although it is well established that adenosine is released during acute ischemia, little is known of the behaviour of adenosine levels following treatment of coronary lesion by percutaneous transluminal coronary angioplasty (PTCA). Using high performance liquid chromatography, we measured intracoronary adenosine levels before and 5 min after PTCA in ten patients with one-vessel disease and a significant (> 70%) coronary stenosis. Adenosine levels decrease in all patients after PTCA. Nevertheless, more studies are now necessary to evaluate the possible predictive value (with regard to restenosis) of coronary adenosine levels after PTCA.

Adenosine↗
PubMed1994

Counter irritation test in primary fibromyalgia.

In primary fibromyalgia the main symptom is diffuse pain predominating at tender points which are sensitive to palpation. The aim of this study was to compare the effects on the amplitude of the nociceptive flexion reflex of the lower limb (RIII reflex) of applying painful pressure to the tender points with the effects of the same pressure applied to other points of the body or to the same part of the body in control subjects. This method was chosen because previous studies have shown that it was possible to activate the diffuse noxious inhibitory system using a "counter-irritation" stimulation. Our study was carried out on 18 fibromyalgic patients and on 12 control subjects. During the counter-irritation procedure, consisting of applying pressure with a mechanical dolorimeter to tender points, a clear cut and significant decrease in the amplitude of the RIII response was observed in 6 patients. In conclusion, in view of the subjective nature of the criteria used at present to diagnose primary fibromyalgia, we would like to suggest that a positive counter-irritation test be adopted as a further obligatory criterion, since it has been clearly established that the diffuse noxious inhibitory control responsible for the decrease in the RIII amplitude can be activated only when the subjects undergo intense nociceptive stimulation.

Adult↗
PubMed1994

Use of HPLC to measure circulating adenosine levels in migrainous patients.

Adenosine is a powerful natural vasodilator that could be involved in migraine. It is difficult to assay this nucleoside, however, because it has a short half-life. We have used HPLC to compare the concentrations of blood adenosine sampled in crisis-free intervals and during crisis periods in ten patients with common migraine and have compared these levels to those noted in a control population. Our sampling technique uses vacuum suction and enables rapid mixing of the blocking solution and whole venous blood. This results in reproducible HPLC assays. We also show that, during a migraine crisis, mean blood adenosine levels increase by 47%. However, the origin of this adenosine release is difficult to define.

Adenosine↗
PubMed1994

Adenosine in painful legs and moving toes syndrome.

Painful legs and moving toes is a rare syndrome with controversial physiopathology. We report two cases that were relieved by applying transcutaneous vibratory simulation. The pain relief was objectively evaluated using the nociceptive flexion reflex of the lower limb (RIII reflex). In these patients, we found a deficiency in circulating adenosine levels, which was not found in other chronic painful syndromes (sciatic pain). Based on these observations, we successfully treated patients with painful legs and moving toes by the administration of ATP. The deficit in blood adenosine may be an explanation of the physiopathology of this syndrome.

Adenosine↗
PubMed1994

Objective evaluation of pain perception in patients with schizophrenia.

The pain thresholds of patients with schizophrenia often seem to differ from those of healthy subjects. In the present study we assessed the pain thresholds of ten patients with schizophrenia, and of ten controls, by measuring the leg flexion nociceptive reflex threshold: the stimulation threshold at which this reflex is triggered, is known to be correlated with the pain threshold. Our conclusion is that, in most cases, the increase in pain threshold is the result of 'attitude' and not of alterations in brain function.

Adult↗
PubMed1994

Anticholinesterases and experimental envenomation by Naja.

Danger from snake bites, especially those of Elapidae, pose a public health problem in a large number of tropical and sub-tropical countries. Since the advent of serotherapy, the morality rate has decreased, but suitable sera are not always available, explaining the usefulness of developing symptomatic treatments. The present study is a test of the preventative and curative efficacy of anticholinesterases in the treatment of Naja haje haje venom envenomation. It is clearly shown that the early use of these products leads to a considerable increase in the LD50 in mice having undergone experimental envenomation.

Animals↗
PubMed1993

[Nociceptive flexion reflex of the leg. Use after surgical treatment of herniated disk].

In patients suffering from acute sciatica due to herniated disk Lasegue's manoeuvre inhibits the leg flexion nociceptive reflex (RIII reflex) in either the ipsilateral or the contralateral limb. This is thought to be due what is called "diffuse noxious inhibitor control" modulating the activity of a group of convergent spinal neurons. The purpose of this study was to determine whether surgical resection of the herniated disk in patients suffering from sciatica might relieve this so-called "counter-irritation". Among 10 patients whose sciatica resulted from herniated disk, the decrease in amplitude of the RIII response observed when Lasegue's manoeuvre is applied disappeared in 7 patients, 6 to 8 days after surgical resection of the herniated disk. These results suggest that this test might be a useful tool for postoperative prediction of radicular compression.

Adult↗
PubMed1993

Utilization of aspirin, quinine and verapamil in the prevention and treatment of scorpion venom intoxication.

Aside from serotherapy, the treatment of scorpion venom intoxication is symptomatic. The aim of this study was to compare the efficacy of drugs usually used in scorpion venom intoxications (atropine, propranolol) to that of other compounds, chosen in light of the pathophysiology of scorpion venom intoxication: dipyridamole, doxapram, quinine formate, lysine-acetyl-salicylate, valproate and verapamil. Using mice, the parameters evaluated were the preventive and therapeutic effects of drugs during experimental venom intoxication by Androctonus australis Hector and one of its toxins AaH 1, and by Buthus occitanus and Tityus serrulatus tunetanus on the other hand. It was found that although most of the drugs used could prolong the survival of the animals, the administration of verapamil and more so that of aspirin or quinine formate led to a 50 to 100% loss of venom and toxin toxicity, depending on the drug and the origin of the venom. In the case of propranolol, doxapram, atropine, dipyridamole and valproate, no or little protection were observed. If these results are confirmed in humans, the systematic use of these drugs could be a simple means for treating scorpion venom intoxication. The problem of scorpion venom intoxication poses a health problem both in the North African Maghreb and in the Americas. As a result of considerable information campaigns, the number of scorpion venom intoxications in Tunisia has dropped from 3000 in 1967 to 1000 per year in the 1980s. Serotherapy has reduced mortality to 0.35%, most deaths occurring in underweight children. In light of the large number of countries in which there is a risk of scorpion venom intoxication in the summertime, however, its prevention and treatment remain a major problem.

Animals↗
PubMed1993

Central analgesic effect of valproate in patients with epilepsy.

Clinical practitioners have often observed in the course of their daily work that the pain thresholds of epileptic patients seem to differ from those of healthy subjects. These patients can suffer from quite severe traumatic lesions without apparently experiencing any pain. Previous studies have shown that the absence of pain is due to treatment, since most antiepileptic drugs also have analgesic effects. In the present study, it was proposed to assess the pain thresholds of 15 epileptic patients (with tonic-clonic seizures generalized at outset) treated with valproate, by measuring the leg flexion nociceptive reflex (or RIII reflex) threshold: the stimulation threshold at which this reflex is triggered is known to be correlated with the pain threshold. The results were compared with 15 control subjects. The nociceptive threshold of the patients with valproate treatment was significantly higher than that of the control population. The nociceptive threshold was also in good correlation with the valproate plasma level. These data are discussed from the point of view of the gaba-ergic system and mechanisms possibly involved.

Adolescent↗
PubMed1993

Substance P-like immunoreactivity and analgesic effects of vibratory stimulation on patients suffering from chronic pain.

By applying vibratory stimulation to patients suffering from pain, it is possible to set up an inhibitory control on the pain pathways which is based on the activation of large-sized afferent fibres. The exact mechanisms responsible for these analgesic effects still remain to be determined, however. For this purpose, we investigated in the present study whether or not the analgesic effects were accompanied by a decrease in the CSF substance P-like immunoreactivity levels (SPLI) of seven patients suffering from chronic pain, who were fitted with a ventriculo-peritoneal drain. The SPLI levels were determined before and after 30-min vibratory stimulation sessions. The results show that the SPLI levels decreased as the result of the vibration, but this decrease seems to be too slight to account for the pain relief obtained.

Adult↗
PubMed1993

[Met-enkephalin and substance P. Comparison of CSF levels in patients with chronic pain based on a sampling procedure].

The purpose of this study was to evaluate the Met-enkephalin and the SP-like immunoreactivity levels in the CSF of 16 patients suffering from chronic sciatalgia and to compare them with those of 8 control subjects. Eight of the patients had a ventriculo-peritoneal shunt which made it possible to collect samples of CSF painlessly. For the others patients and controls, CSF samples were collected by lumbar puncture. The results showed that there was no difference in the Met-enkephalin and SP levels whatever the method of sample collection. On the other hand, SP-like immunoreactivity was lower in patients suffering from chronic pain.

Adult↗
PubMed1993

[Transcutaneous mechanical vibrations: analgesic effect and antinociceptive mechanisms].

Although vibration has been used empirically for a long time in medicine, it was only about ten years ago that it began to be investigated scientifically. In the first part of this paper, we review the main data showing that vibratory stimulations can relieve both acute and chronic pain. In the second part, we consider the mechanisms responsible for the observed analgesic effects and discuss the nature of the sensory receptors involved and the effects of their activation on the triggering of central pain control systems.

Analgesia↗
PubMed1993

Nociceptive threshold in hypothyroid patients.

The purpose of this study was to measure the nociceptive threshold in hypothyroid patients by determining when the nociceptive flexion reflex of the lower limb occurs under percutaneous electrical stimulation of the sural nerve, given that this threshold is well correlated with pain sensation. Twelve hypothyroid patients and twelve control subjects participated in the study. In the case of the hypothyroid patients, the nociceptive flexion reflex (or RIII reflex) was measured before and six weeks after the onset of substitution treatment. The results clearly indicate that the nociceptive threshold of the patients with hypothyroidism was significantly higher than that of the control subjects. After six weeks of substitution treatment, the RII threshold return to normal. The analgesia observed in the hypothyroid patients in this study do not appear to be correlated with the blood TSH level. The possible mechanisms of these analgesic effects are discussed.

Aged↗
PubMed1992

Nociceptive threshold in patients with epilepsy.

Clinical practitioners have often observed in the course of their daily work that the pain thresholds of epileptic patients seem to differ from those of healthy subjects. These patients can suffer from quite severe traumatic lesions without apparently experiencing any pain. Since they are usually under treatment for epilepsy, it is difficult to determine whether the absence of pain is due to these patients' epileptic condition or to its treatment, since most antiepileptic drugs also have analgesic effects. In the present study, it was proposed to assess the pain thresholds of 15 epileptic patients (10 with tonic-clonic seizures generalized at outset and 5 with temporal lobe epilepsy), by measuring the leg flexion nociceptive reflex (or RIII reflex) threshold: the stimulation threshold at which this reflex is triggered is known to be correlated with the pain threshold. The nociceptive threshold of the patients with generalized epilepsy was not found to differ from that of the control population, whereas that of the patients with temporal lobe epilepsy was spontaneously high and was not reversed upon injecting naloxone. These data are discussed from the point of view of the pain pathways and mechanisms possibly involved.

Adolescent↗
PubMed1992

Identifying the afferents involved in movement-induced pain alleviation in man.

It has been clearly established that the perception of nociceptive stimulus decreases in intensity when movement is initiated in the part of the body to which the stimulus is applied. The pain alleviation is probably at least partly due to the activation of afferents which occurs during the movement. The present experiments were carried out with a view to investigating which groups of afferent fibres is mainly responsible for the gating of the nociceptive messages which occurs during movements. In eight volunteers we investigated the changes in the amplitude of the nociceptive leg flexion reflex (RIII) when the subjects were at rest, when they were performing active or passive ankle movements and when the spindle proprioceptive pathway was mobilized by applying vibratory stimulation to the Achilles tendon. Similar experiments were also carried out with eight other volunteers after anaesthetizing the ankle skin mechanoreceptors. This method was chosen because a clear-cut correlation is known to exist between the amplitude of the nociceptive motor reflex and the intensity of the pain perceived by the subject. The data obtained clearly show that anaesthesia of cutaneous mechanoreceptors connected to the large diameter afferent fibres prevented the decrease in the motor response which otherwise accompanied both active and passive movements. Activation of the Ia fibre group by tendon vibration resulted on the contrary in an increase in the amplitude of the motor response. Movement-induced pain alleviation therefore does not mainly involve the activation of the Ia group of fibres.

Adult↗
PubMed1992

Analgesic effect of indomethacin shown using the nociceptive flexion reflex in humans.

This study investigated whether indomethacin has an analgesic effect on the central nervous system. As analgesics which affect the central nervous system produce a correlated decrease in the subjective sensation of pain and in the nociceptive reflex in humans, the amplitude of the nociceptive flexion of the biceps femoris was studied. Eight patients (six men, two women) aged 35-70 years (mean 51) with rheumatic diseases were included in the study. Each patient was his or her own control and was given a single intramuscular injection of either 50 mg of indomethacin or a placebo. A placebo controlled, double blind experimental design was used. Patients were evaluated before and 30, 60, and 75 minutes after the injection. Seventy five minutes after injection, indomethacin gave a 54% decrease in the amplitude of the nociceptive reflex, whereas the placebo produced a decrease of only 12%. This suggests that indomethacin exerts a depressive effect on the amplitude of the nociceptive reflex and affects the central nervous system as part of its analgesic action.

Adult↗