FRI0612-HPR EFFECT OF THERMOFORMABLE ORTHOSES ON FOOT FUNCTION IN RHEUMATOID ARTHRITIS PATIENTS: PRELIMINARY RESULTS FROM AN OPEN CLINICAL TRIAL

Background:

Orthoses and footwear can play an important role in managing foot pathology in patients whose systemic disease is controlled. Foot orthoses are frequently prescribed in clinical practice as an intervention for people with rheumatoid arthritis (RA).

Objectives:

The aim of our study is to evaluate the impact of thermoformable orthoses on the functional index of the foot (FFI) in patients with rheumatoid arthritis.

Methods:

We conducted an open clinical trial, having consecutively included 14 patients (85.7% female, average age 54.8 ± 10 years) suffering from rheumatoid arthritis (median progression time of 9 years [5 - 12]). The average DAS28 was 2.7 ± 1.2 and the functional impact objectified by the Health Assessment Questionnaire (HAQ) was on average 0.9 ± 0.7.

The median deadline from the start of RA and the onset of the foot problem was 3 years [0 – 7,75]. The foot problem was bilateral in 100% of the cases and inaugural in 85.7% of the cases.

We evaluated the functional impact of foot injury for all our patients at baseline and 8 weeks after the use of thermoformable orthoses, based on the FFI (Foot function Index) measuring the impact of foot pathology on function in terms of pain, disability and activity limitation.

The comparison of the FFI domains before and after the use of orthoses was carried out using parametric or nonparametric paired tests using The SPSS statistical software.

Results:

With the use of foot orthoses, FFI values decreased in all subscales (p=0,024) (pain, disability and activity limitation). This reduction was significant for disability (0,011) but not for pain and activity limitation.

There were no significant correlations between the global FFI and the progression of RA, the duration of foot damage and the functional impact measured by the HAQ.

Table 1. The comparison of the FFI domains before and after the use of orthoses.

psignificatif if< 0,05; Test used: Non-parametric test for two linked samples.

Conclusion:

Foot orthoses were effective as an adjuvant in the management of rheumatoid foot. They significantly reduced disability as measured by the FFI. The absence of factors associated with pain and limitation of activity could possibly be related to the small sample size.

Disclosure of Interests:

None declared

FRI0620-HPR THE EFFECT OF THERMOFORMABLE FOOT ORTHOSES ON WALKING IN RHEUMATOID ARTHRITIS PATIENTS: PRELIMINARY RESULTS FROM AN OPEN CLINICAL TRIAL

Background:

Foot pain is common in rheumatoid arthritis and appears to persist despite modern day medical management.

Objectives:

To evaluate the impact of thermoformable foot orthoses on walking in rheumatoid arthritis (RA) patients.

Methods:

This is a open clinical trial, that included 14 consecutive patients (85,7% female, mean age 54,8 ± 10 years) with RA (median duration of progression of 9 [5-12] years), the average DAS28 was 2,7+/-1,2 and the functional impact objectified by the Health Assessment Questionnaire (HAQ) was on average 0.9 ± 0.7.

The foot problem was bilateral in 100% and inaugural in 85.7% of the cases.

The 14 rheumatoid subjects were examined and appropriate foot orthoses were prescribed according to each patient’s needs. All the patients were evaluated at baseline and 8 weeks after use of orthoses. Gait pain, difficulty walking and the 10 Meter Walk test were noted at each appointment.

We used dynamic baropodometric analysis to assess postural evaluation. We calculated the lateral-medial index of each foot before and after the use of orthoses.

Table 1.

Assessment of walking before and after the use of orthoses

Before orthosesAfter orthosespPain when walking*(EVA 0-10)5 [3-5,2]0 [0-2]0,002Difficulty walking* (0-10)- In house4 [3-5,2]2 [0-2]0,002- Outside6 [4,7-7]2 [1,5-2,5]0,0210 Meter Walk test**(Normal comfortable speed)- Nomber of steps18,64 ± 3,716,9 ± 50,2- Duration (sec)11,9 ± 4,611,8 ± 5,20,9- Walking speed (m/min)56,4 ±17,758,6 ± 20,30,6latero-medial (L/M) index**- L/M index of the right foot1,18 ± 0,171,23 ± 0,230,1- L/M index of the left foot1,25 ± 0,171,26 ± 0,190,9

*median and quartile

**average and standard deviation

p significant if< 0,05

Results:

A significant decrease in walking pain (p = 0.002) and difficulty walking (p = 0.02) was found with the use of orthoses. The variations in 10 meter walk test and dynamic baropodometric parameters were not significant (p>0,05).

There were no significant correlations between pain and difficulty walking, the progression of RA, the duration of foot damage and the functional impact measured by the HAQ.

Conclusion:

Thermoformable foot orthoses significantly reduced pain and difficulty walking. The absence of factors associated with pain and difficulty walking could possibly be related to the small sample size.

Disclosure of Interests:

None declared

Adenosine plasma level correlates with homocysteine and uric acid concentrations in patients with coronary artery disease

The role of hyperhomocysteinemia in coronary artery disease (CAD) patients remains unclear. The present study evaluated the relationship between homocysteine (HCys), adenosine plasma concentration (APC), plasma uric acid, and CAD severity evaluated using the SYNTAX score. We also evaluated in vitro the influence of adenosine on HCys production by hepatoma cultured cells (HuH7). Seventy-eight patients (mean age ± SD: 66.3 ± 11.3; mean SYNTAX score: 19.9 ± 12.3) and 30 healthy subjects (mean age: 61 ± 13) were included. We incubated HuH7 cells with increasing concentrations of adenosine and addressed the effect on HCys level in cell culture supernatant. Patients vs. controls had higher APC (0.82 ± 0.5 μmol/L vs 0.53 ± 0.14 μmol/L; p < 0.01), HCys (15 ± 7.6 μmol/L vs 6.8 ± 3 μmol/L, p < 0.0001), and uric acid (242.6 ± 97 vs 202 ± 59, p < 0.05) levels. APC was correlated with HCys and uric acid concentrations in patients (Pearson's R = 0.65 and 0.52; p < 0.0001, respectively). The SYNTAX score was correlated with HCys concentration. Adenosine induced a time- and dose-dependent increase in HCys in cell culture. Our data suggest that high APC is associated with HCys and uric acid concentrations in CAD patients. Whether the increased APC participates in atherosclerosis or, conversely, is part of a protective regulation process needs further investigations.

A2A adenosine receptor function in patients with vasovagal syncope

AIMS

Adenosine is a possible mediator in vasovagal syncope (VVS) via the activation of its receptors. High expression of adenosine A2A receptors (A2AR) has been reported in VVS. The function of these over-expressed receptors in this population has never been evaluated.

METHODS AND RESULTS

We used Adonis, a specific-made antibody with A2AR agonist properties, to evaluate binding parameters (i.e. dissociation constant KD) and cAMP production (i.e. EC50) by peripheral blood mononuclear cells of 16 VVS patients. Eight healthy volunteers served as controls. A2AR expression was higher in patients than controls; mean: 11.5 ± 1.2 vs. 7.7 ± 0.8 AU, P = 0.04. Also, KD values were higher in patients than controls: 2.1 ± 0.02 × 10(-7) vs. 5 ± 1 × 10(-8) M, P < 0.01 In controls, KD values were lower than EC50 (5 ± 1.7 × 10(-8) vs. 2.8 ± 0.4 10(-7) M, P < 0.01), but in patients, KD values did not differ from EC50: 2. ± 0.2 × 10(-7) vs. 2.5 ± 0.4 × 10(-7) M, P > 0.05. However, four patients had lower EC50 (3.5 ± 0.3 × 10(-8) M) than KD (2.9 ± 1.2 × 10(-7) M; KD/EC50 = 9.6), suggesting the presence of spare receptors.

CONCLUSION

The function of A2AR of patients with VVS was preserved since their stimulation by Adonis led to cAMP production with an EC50 comparable with those in controls. However, their affinity was lower than those of controls. Our results suggest that A2AR are implicated in the physiopathology of VVS.

The effect of circulating adenosine on cerebral haemodynamics and headache generation in healthy subjects

Adenosine is an endogenous neurotransmitter that is released from the brain during hypoxia and relaxes isolated human cerebral arteries. Many cerebral artery dilators cause migraine attacks. However, the effect of intravenous adenosine on headache and cerebral artery diameter has not previously been investigated in man and reports regarding the effect of intravenous adenosine on cerebral blood flow are conflicting. Twelve healthy participants received adenosine 80, 120 microg kg(-1) min(-1) and placebo intravenously for 20 min, in a double-blind, three-way, crossover, randomized design. Headache was rated on a verbal scale (0-10). Regional cerebral blood flow (rCBF) with 133Xe inhalation and single-photon emission computed tomography (SPECT) and MCA flow velocity (V(MCA)) with transcranial Doppler, were measured in direct sequence. Six participants developed headache during 80 microg kg(-1) min(-1) and six during 120 microg kg(-1) min(-1) compared with none on placebo (P = 0.006). The headache was very mild and predominantly described as a pressing sensation. When correcting data for adenosine-induced hyperventilation, no significant changes in rCBF (P = 0.22) or V(MCA) (P = 0.16) were found between treatments. A significant dilation of the superficial temporal artery (STA) was seen (P < 0.001). These results show that circulating adenosine has no effect on rCBF or V(MCA), while it dilates the STA and causes very mild headache.

Evidence that free radical generation occurs during scorpion envenomation

Although it is well established that symptomatology, morbidity and death following scorpion envenomation are due to increases in neurotransmitter release secondary to toxins binding to voltage-sensitive sodium channels, the mechanism by which venom action is involved in damaging heart, liver, lungs and kidneys remains unclear. We hypothesized that scorpion toxins could induce the generation of high levels of free radicals responsible for membrane damage in organs targeted by venom action. We have investigated lipid peroxidation in different organs, through the evaluation of thiobarbituric acid reactive substances (TBARS), after experimental envenomation of rats by toxic fractions of Androctonus australis Hector venom. We have shown that scorpion toxins cause considerable lipid peroxidation in most vital organs. We also evaluated the protective effects of antioxidants in mice injected with lethal doses of toxins. Among the drugs tested, N-acetylcysteine (NAC) was effective in protecting the mice when injected prior to toxin application. However, the free radical scavenging properties of NAC seem less implicated in these protective effects than its ability to increase the fluidity of bronchial secretions. We therefore conclude that free radical generation only plays a minor role in the toxicity of scorpion venom.

Small conductance calcium-activated K+ channels, SkCa, but not voltage-gated K+ (Kv) channels, are implicated in the antinociception induced by CGS21680, a A2A adenosine receptor agonist

It has been shown that A2A adenosine receptors are implicated in pain modulation. The precise mechanism by which activation of A2A receptors produces analgesic effects, however, remains unclear. The aim of this study was to investigate the possible involvement of apamin-sensitive calcium-activated potassium channels (SKCa) and voltage-gated potassium (Kv) channels in A2A receptor activation-induced analgesic effects. Using mice, we evaluated the influence of apamin, a non specific blocker of SKCa channels, Lei-Dab7 (an analog of scorpion Leiurotoxin), a selective blocker of SKCa2 channels, and kaliotoxin (KTX) a Kv channel blocker, on the CGS 21680 (A2A adenosine receptor agonist)-induced increases in hot plate and tail pinch latencies. All drugs were injected in mice via the intracerebroventricular route. We found that apamin and Lei-Dab7, but not KTX, reduced antinociception produced by CGS21680 on the hot plate and tail pinch tests in a dose dependent manner. Lei-Dab 7 was more potent than apamin in this regard. We conclude that SKCa but not Kv channels are implicated in CGS 21680-induced antinociception.

In vivo neurotoxicity of Androctonus australis hector scorpion venom: evidence that the supra-thoracic nervous system is not implicated in the clinical manifestations

The severity of scorpion stings is related to the highly active neurotoxins in the venom. In this study, rats whose supra-spinal central nervous system was deprived of its peripheral connections were experimentally poisoned by the venom of Androctonus australis hector scorpion. Clinical signs of severity were not modified when the rats had previously undergone high medullar section. These results suggest that the supra-thoracic nervous system is not implicated in the neurotoxicity manifestations of scorpion envenomation.

Adenosine and hemodialysis in humans

BACKGROUND

Infections and hypotension are serious complications that develop during hemodialysis (HD) treatment. Adenosine (ADO), a strong hypotensive and immunosuppressive agent, may participate in these two HD complications, because high concentrations of ADO metabolites are found in dialyzed human plasma. ADO, which is released by endothelial cells, is quickly transformed into inosine (INO) by plasmatic ADO deaminase (ADA) and mononuclear cell ADO deaminase (MCADA). In plasma, the degradation of ADO into INO and its uptake by red blood cells (RBC) are both very rapid, resulting in the short half-life of ADO in blood.

METHODS

Using liquid chromatography, we evaluated ADO and INO plasma concentrations before and after HD session.

RESULTS

Before the HD session, ADO and INO plasma concentrations were higher in hemodialyzed patients than in controls and in peritoneally dialyzed patients. At the end of the HD session, ADO plasma concentration was increased. ADO plasma concentration for the undialyzed patients was in the same range as that of the controls. Before HD, ADA activity was higher in hemodialyzed patients (559 +/- 349 IU) than in controls (219 +/- 48 IU), and the activity rose during the session (665 +/- 135 IU). ADA activity in the undialyzed patients (222 +/- 80 IU) was in the same range as that of the controls (219 +/- 48 IU). Before the HD session, the MCADA activity (247 +/- 144 IU) was lower than in controls (624 +/- 99 IU). HD did not modify ADO RBC uptake. ADO inhibited mononuclear cell proliferation and interferon-gamma production in humans. Finally, as much as 50 microM INO does not inhibit ADO uptake by RBC and does not modify ADA and MCADA activities.

CONCLUSIONS

These data indicate that chronic HD inhibited MCADA activity and increased ADO plasma concentration. Both high ADO plasma concentration and low MCADA activity may be involved in dialysis-induced immune system failure and thereby favor infectious diseases.

High adenosine plasma concentration as a prognostic index for outcome in patients with septic shock

OBJECTIVE

Sepsis and septic shock are a common cause of mortality in critically ill patients. Many substances have been implicated in the pathophysiology of these syndromes. We postulated that adenosine may be implicated in the sepsis- or septic shock-induced blood pressure failure. Indeed, this nucleoside is a strong endogenous vasodilating agent released by endothelial cells and myocytes under circumstances of metabolic stress, such as during critical illness.

DESIGN

A prospective, comparative observational study.

SETTING

The adult intensive care unit of a tertiary care university hospital.

PATIENTS

We measured adenosine plasma concentration (APC) in patients with severe sepsis (n = 11), in patients with septic shock (n = 14), in patients with hemorrhagic traumatic shock (n = 14), and in 12 healthy volunteers. APC was evaluated every 12 hrs over 3 days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

At study entry, we found that APC was higher in patients with septic shock (mean +/- so = 8.4 +/-3.5 micromol/L) than in patients with hemorrhagic traumatic shock (1.1 +/- 0.6 micromol/L) and controls (0.8 +/- 0.3 micromol/L). Intermediate values (3.9 +/- 1.9 micromol/L) were found in patients with severe sepsis. APC in patients with traumatic shock did not differ from controls. In the course of the hospitalization, for both sepsis and septic shock patients, APC decreased significantly but remained higher than controls 72 hrs after entry into the study. In the septic shock group, APC was significantly higher in the nonsurvivor group (n = 6) than in the survivor group (n = 8), whatever the time of sample collection and assay.

CONCLUSIONS

High adenosine plasma concentrations are found in patients with septic shock but not during traumatic shock, or in healthy volunteers. Intermediate values of circulating adenosine are found in patients with severe sepsis. APC may be a prognostic index for outcome in septic patients, with much higher values being found in nonsurvivors.

Modulation of adenosine concentration by opioid receptor agonists in rat striatum

There is evidence that adenosine and morphine interact in the striatum. However, little is known about the precise role of the opioid receptor subtypes implicated in the modulation of adenosine tissue concentration and in adenosine receptor expression and function. We sought to evaluate, in the absence of withdrawal symptoms, the effects of the short-term administration of selective mu-, delta- or kappa-opioid receptor agonists on adenosine concentration and on adenosine A(2A) receptor function in rat striatum. Adenosine A(2A) receptor was chosen because the neuronal sub-population expressing this receptor coexpresses enkephalin, suggesting that adenosine A(2A) receptor may be regulated by opioid receptor agonists. Oxymorphone hydrochloride mu-opioid receptor agonist, 6 mg/kg/day), +[-(5 alpha,7 alpha, 8 beta)-(-)-N-methyl-N(7-(1-pyrrolidinyl)1-oxaspiro (4.5)dec-8-yl) benzenacetamide] (U69593) (kappa-opioid receptor agonist, 0.75 mg/kg/day), and (+)-4[(alpha R)-alpha-((2S,5R)-4-allyl-2, 5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide) (SNC80) (delta-opioid receptor agonist, 9 mm/kg/day), or vehicle, were administered i.p 3 x daily during 5 days to groups of rats (n=6). We also investigated the effects of opioid receptor agonists on adenosine uptake by striatal cell extracts. We found that administration of mu- or delta-opioid receptor agonists significantly decreased adenosine uptake in striatal cell extracts and increased adenosine concentration (mean+24% and +45% for mu- and delta-opioid receptor agonist, respectively, relative to controls). None of the receptor agonists tested induced obvious modifications of adenosine A(2A) receptor function. However, the delta-opioid receptor agonist induced an increase in adenosine A(2A) mRNA expression (mean 44%). We conclude that mu and delta receptor agonists inhibit adenosine uptake by striatal cell extracts and increase adenosine concentrations in rat striatum.

Toxicity during early development of the mouse nervous system of a scorpion neurotoxin active on sodium channels

The lethal effects of scorpion envenomation is due to neurotoxins active on voltage-sensitive sodium channels. Dysfunctions of the peripheral and central nervous systems with neurological manifestations are commonly observed after scorpion stings, specially in young children. Since the neurotoxicity of venom fraction is greatly higher by intracerebroventricular than by subcutaneous injections, a direct effect of venom on CNS cannot be excluded specially in infants where the blood-brain barrier is not fully functional. We investigated the activity of a neurotoxin from the scorpion Androctonus australis hector (AahII) in newborn mice at 3, 7 and 14 days after birth and in adults. Young mice (P3, P7) were more sensitive to AahII injected subcutaneously than were adults, but were less sensitive to intracerebroventricular injection. The affinity of AahII for its receptor site on brain synaptosomes from P3 and P7 mice was slightly higher and the density of the binding sites was half that of adult mice. After subcutaneous injection of [125I]-AahII it was also observed that a small amount of radioactivity was found in brains of neonate mice but not in that of adults. This amount is however extremely lower than the value of the LD50 determined by intracerebroventricular injection. Results are consistent with a peripheral action of AahII and show that its toxic activity changes during the mouse nervous system development.

Relationships between the anti-HIV V(3)-derived peptide SPC(3) and lymphocyte membrane properties involved in virus entry: SPC(3) interferes with CXCR(4)

SPC(3) is a multiple antigen peptide derived from the V(3) loop of human immunodeficiency virus (HIV) envelope (Env). It exerts a potent anti-HIV activity whereas it alters neither Env expression nor binding to CD(4). Here, SPC(3) binding characteristics, its subsequent intracellular fate and the fact that it inhibited SDF(1)alpha binding to the lymphocyte surface provided strong arguments to conclude that it exerts its anti-HIV activity through interference with the CXCR(4) coreceptor. In contrast, it interferes with none of the other major surface proteins and mechanisms involving V(3) and implicated in infection, as shown here. This work identifies the target mechanism of SPC(3).

Effects of percutaneous transluminal coronary angioplasty on coronary adenosine concentrations in humans

BACKGROUND

Even minimal amounts of adenosine is released during myocardial ischemia. Its role in coronary blood flow has been extensively studied, but little is known about its behaviour during percutaneous transluminal angioplasty (PTCA) in man.

MATERIAL AND METHODS

Using in situ samples the aim of this study was to evaluate adenosine plasma concentration before and after PTCA. Ten patients (8 men and 2 women, mean age 65 +/- 9 years) with a single stenosis of the left anterior descending coronary artery (LAD) of at least 70% and 10 healthy volunteers (4 men and 6 women, mean age 55 +/- 9 years) were included in the study.

RESULTS AND DISCUSSION

We found that there is a close relationship between the degree of the stenosis and the adenosine concentrations in the great cardiac vein and in the LAD, and that after PTCA there is a drop in adenosine concentration downstream from the stenosis. This study confirms the crucial role of adenosine in coronary blood flow control.

Cyclosporine A and purinergic receptors in rat kidney

Previous reports have demonstrated that Cyclosporine A (CyA) chronically administered induces an increase in adenosine plasma concentration by inhibiting adenosine uptake by red blood cells (RBC). We hypothesized that this effect may modulate, by a down regulation, the mRNA expression of adenosine receptors in rat kidney. Since high blood pressure (HBP) is a classical side effect of CyA treatment, nicardipine, a dihydropyridine calcium channel blocker, is often associated with CyA in treatment. To distinguish between the effects of CyA-induced HBP and the effects of CyA by itself, we have evaluated the effects of CyA and/or nicardipine on the mRNA expression of A1 and A2a adenosine receptors. The study was performed on five groups of rats (n= 8) receiving during 21 days either serum saline (0.5 ml i.p), CyA (12 mg/kg/day, i.p), nicardipine (1.2 mg/kg i.p) or nicardipine + CyA. The last (or fifth) group was injected with vehicle (0.5 ml i.p). Blood samples for adenosine assay were collected in the renal artery at day 21, just before the rat kidneys were removed for quantitation of adenosine A1 and A2a mRNA concentration by RT-PCR. We make two conclusions :i) Nicardipine induces a decrease in mRNA expression of A1 but not of A2a adenosine receptors. However, because nicardipine lowered both blood pressure and A1 mRNA expression, it is not possible to conclude if A1 mRNA decrease is implicated in the nicardipine effects on blood pressure.ii) CyA induces an increase in renal artery adenosine concentration and a decrease in mRNA expression of A1 and A2a adenosine receptors.

An ultrarapid prognostic index in microprolactinoma surgery

OBJECT

Prolactinomas account for approximately 40% of pituitary tumors. If the tumor does not exceed 10 mm at its largest diameter (microprolactinoma), the chances of definitive cure as a result of surgery alone vary from 62 to 89% depending on the series. Until now, however, there was no mechanism to predict whether total excision of a tumor had been accomplished. To improve the chances of total excision, we compared the peri- and postoperative kinetics of circulating prolactin (PRL) in patients judged to be cured and those not cured.

METHODS

The pre-, peri-, and postoperative variations in blood PRL concentrations were determined using assays conducted at 10-minute intervals. Of the 36 patients included in the study, 27 were considered cured (resumption of a normal menstrual cycle within 6 months, PRL concentration at 9 days [mean +/- standard deviation 2.5+/-2.1 ng/ml] and 12 months [4.5+/-2.2 ng/ml] after the operation < 10 ng/ml and normally stimulated by metoclopramide and thyrotropin-releasing hormone [TRH]). Nine patients were not cured (PRL 20+/-15.7 ng/ml at 9 days after surgery, with no response to metoclopramide and TRH). The kinetics of PRL decrease in definitively cured patients were characterized by the following: 1) the initial slope of the curve decreased by at least 11% within the first 10 minutes after resection, and 2) immediate postoperative PRL concentrations were 20 ng/ml or less.

CONCLUSIONS

The measurement of the kinetics of PRL decrease during surgery allows the chance of gross-total resection to be successfully predicted less than 25 minutes after excision of the adenoma. Provided an ultrarapid assay is available (the test used in the present study took < 15 minutes), this prognostic index would be useful to make a decision to continue the surgical procedure when the initial PRL slope is judged to be insufficient. Its use may also be extended to other pituitary tumors such as somatotropic adenoma and basophilic adenoma (Cushing's disease).

The hormonal response to stress is not modified by the dramatic decrease in prolactin plasma concentration during surgery for microprolactinoma

OBJECTIVES

To determine the endocrine response to surgical stress in a homogeneous population of 36 women with microprolactinomas, particularly to evaluate the effect of the sharp decrease in plasma prolactin on stress induced hormonal secretion. In addition, the effects of exogenous opiates on prolactin secretion were studied.

METHODS

The plasma kinetics of cortisol, prolactin, ACTH, GH, and beta-endorphin like immunoreactivity (beta-ELI) were analysed by including patients operated on with strict anaesthetic and surgical protocols, and by sampling blood every 10 minutes, starting at premedication up to 3 hours after induction.

RESULTS AND CONCLUSIONS

(a) Surgical stress or opiate administration did not induce prolactin release in patients with microprolactinoma. (b) The dramatic decrease in prolactin concentrations have apparently no effect on the release of other hormones involved in stress. (c) The existence of an early GH peak, independently of any surgical procedure, strongly suggests that GH is released by surgical stress whereas beta-endorphin is secreted in response to pain. Thus GH may be a useful marker of surgical stress.

Adenosine and the nervous system: pharmacological data and therapeutic perspectives

1. Adenosine acts on a family of G-protein-coupled receptors called purinoreceptors. 2. Four subtypes have been cloned and pharmacologically characterized. 3. The principal pharmacological data and structure-function relations for agonist interactions with P1 receptors are presented. 4. We conclude that the potent role of adenosine in the nervous system may be interesting for the development of drugs targeted at purines and their receptors.

Adenosine and migraine

BACKGROUND

Adenosine is a powerful natural vasodilator that participates in the control of cerebral and meningeal blood flow. In this context, it could be involved in the pathophysiology of migraine, since it was previously reported that intravenous adenosine can precipitate crises in migraine patients.

METHODS

We have investigated circulating adenosine levels in 12 patients suffering from migraine without aura, during crises and in crisis-free periods, and have compared the levels noted to those of a population of 10 controls. To determine if there are interactions between adenosine and serotonin, we examined the effect of adenosine and antagonists on the uptake and the release of (14C) serotonin by platelets.

RESULTS AND CONCLUSION

We have reached a dual conclusion: 1) during migraine headaches there is an increase (mean 68%) in circulating adenosine levels and this increase may participate in cephalalgia; 2) activation of A2 receptors by adenosine causes a dose-dependent serotonin uptake by platelets. This inhibition of uptake could participate in the rapid elimination of serotonin in migraine sufferers. As a result of this, the use of adenosine antagonists could be an effective complementary treatment for migraine.

Pancreatic bile-salt-dependent lipase activity in serum of diabetic patients: is there a relationship with glycation?

1. Pancreatic bile-salt-dependent lipase has been detected in human plasma where it has the capability to modify normal low- and high-density lipoprotein composition and structure and to reduce the atherogenicity of oxidized low-density lipoprotein (Shamir R, Johnson WJ, Morlock-Fitzpatrick K, Zolfaghari R, Li L, Mas E, Lombardo D, Morel DW, Fisher EA. Pancreatic carboxyl ester lipase: a circulating enzyme that modifies normal and oxidized lipoproteins in vitro. J Clin Invest 1996; 97: 1696-704). 2. In the present study, we investigated the effect of glycation and particularly that of human serum albumin on the activity of bile-salt-dependent lipase. In vitro, bile-salt-dependent lipase activity decreased in the presence of human serum albumin; however, this was less pronounced in the presence of glycated human serum albumin. In vivo, bile-salt-dependent lipase specific activity was about 2-fold higher in the sera of diabetic patients than in the sera of normal subjects. 3. A significant increase in the specific activity of bile-salt-dependent lipase related to the serum level of glycation was observed. The increase in bile-salt-dependent lipase specific activity was not related to the glucose concentration in serum suggesting that glycation of bile-salt-dependent lipase could not be involved in the observed effects. Although the stability of serum bile-salt-dependent lipase was important enough to allow a systemic action of the enzyme on lipoproteins, it could not explain the higher activity of the enzyme in diabetic serum. 4. We concluded that bile-salt-dependent lipase could be helpful against the premature development of atherosclerosis in diabetes.

Interactions between cyclosporine A and adenosine in kidney transplant recipients

Adenosine is involved in a large number of physiological processes including immune response and vasomotor function. But its precise involvement in renal physiology is poorly understood. We have investigated the putative relationships between cyclosporine A (CsA) and adenosine (ADO) metabolism in kidney transplant recipients (KTR). We first compared ADO plasma levels in three groups of patients and in 10 controls: the first group (N = 14) was composed of CsA-treated KTR; the second group (N = 5) was KTR not treated with CsA, and the third (N = 6) was chronic kidney failure patients. We also measured ADO plasma level in two KTR treated with FK506, a CsA analog. ADO plasma levels in CsA-treated KTR were significantly higher (mean 0.76 microM +/- 0.27) than in the control group (mean 0.31 +/- 0.13; Mean-Whitney test, S = 8.5; P = 2.1 x 10(-4)) and than in the chronic kidney failure group (0.37 +/- 0.16, Mann-Whitney, S = 5.5; P = 1.6 x 10(-3)). In CsA-treated KTR, CsA and ADO plasma levels were significantly correlated (Spearman's, r = 0.8, P = 1.9 x 10(-3)). No significant differences in ADO plasma levels were found between patients with chronic kidney failure and controls (P < 0.05). ADO plasma levels in KTR not treated with CsA were in the same range as those in controls. Finally, the ADO plasma level was increased in the two FK506-treated patients. We also investigated the action of CsA on ADO plasma degradation and uptake by erythrocytes in vitro. No interaction between adenosine deaminase and CsA was found because CsA, in the presence of adenosine deaminase, did not modify the plasma half-life of ADO. Conversely, in the presence of CsA (500 and 1000 ng/ml), the uptake of ADO by erythrocytes was significantly decreased in adenosine deaminase-free samples (analysis of variance, P = 1.8.10(-3) and 1.2 x 10(-4), respectively). We conclude that ADO plasma levels are significantly elevated and correlate with CsA blood level in CsA-treated KTR, and that these high levels are due to CsA inhibition of ADO uptake by red cells. Since ADO and metabolites have well known immunosuppressive and vascular effects, ADO is likely to participate in the immune defect and in the vasoconstriction induced by CsA.

Adenosine and neuropathic pain

Recent studies have reported the possibilities of relieving neuropathic pain by administering adenosine or its analogs. In order to determine if there exists a metabolic anomaly of this nucleoside in patients with neuropathic pain, circulating adenosine levels were compared in three patient groups. The first was composed of individuals suffering from neuropathic pain, the second of patients with nervous system lesions in the absence of pain, and the third was composed of patients suffering from pain resulting from excessive nociception. The adenosine blood levels of these patients were compared to those of a control group. Finally, adenosine in the cerebrospinal fluid (CSF) of some patients was also assayed. The results show that there are reduced levels of blood and CSF adenosine in patients with neuropathic pain. This adenosine deficiency could explain the potential therapeutic effects of administering adenosine or its analogs.

Adenosine and the nervous system: clinical implications

After a review of the metabolism and pharmacology of adenosine, this work will examine the various therapeutic possibilities involving the use of agonists or antagonists of adenosine A1 or A2 receptors in neurological disorders. Promising preclinical results have been obtained with epilepsy, cerebral ischemia, alcoholism, and pain.

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.

Use of dantrolene in experimental scorpion envenomation by Androctonus australis hector

Hyperthermia and profuse perspiration are rarely absent in severe cases of scorpion envenomation. Based on these observations, the aim of this study was to determine the therapeutic effects of dantrolene, on experimental poisoning by the venom of Androctonus australis hector. Dantrolene is a directly acting muscle relaxant which lowers the body temperature in malignant hyperthermia. The results indicate that the early use of this drug raises the LD50 in experimentally poisoned mice. If these results are transposable to humans, dantrolene could be a useful therapeutic adjuvant.

Beta-endorphin in multiple trauma victims

BACKGROUND

In animals and in humans, stress is known to be accompanied by increased beta-endorphin secretion.

METHODS

Blood samples from 47 patients in a state of stress induced by multiple trauma were assessed for beta-endorphin concentration by radioimmunoassays.

RESULTS

We show that there is a clearcut correlation (Spearman's R = 0.72, P = 2.1 x 10(-6) between the level of consciousness evaluated with the Glasgow score and levels of circulating beta-endorphin. In addition, beta-endorphin levels are higher than normal in patients with Glasgow coma with scores higher than seven, and lower than normal in those with Glasgow coma scores of seven or less. Finally, in the complete absence of stress (shown by the lack of brain activity in six irreversible coma patients), there is a severe drop in the level of circulating beta-endorphin.

CONCLUSION

beta-endorphin serum levels correlate with the state of consciousness of multiple trauma patients.

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.

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.

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 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.

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.

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.

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.

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.

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.

[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.