Role of neuroprotective drugs in acute ischemic stroke.
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Publications and source records attributed to V Gallai.
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Analysis of lymphocyte muscarinic cholinergic receptors using quantitative techniques such as radioligand binding assay is made difficult due to the low density of these sites and the lack of subtype-specific selectivity of most available muscarinic ligands. In this study, a combined kinetic and equilibrium labeling technique recently developed for brain tissue was used for labeling the five muscarinic cholinergic receptor subtypes in intact human peripheral blood lymphocytes. No specific muscarinic M1 receptor binding was detectable in human peripheral blood lymphocytes using [3H]-pirenzepine as a ligand. Labeling of M2-M5 muscarinic receptors using [3H]N-methyl-scopolamine (NMS) by occluding various receptor subtypes with muscarinic antagonist and mamba venom resulted in the labeling of M2-M5 receptors in brain as well as in human peripheral blood lymphocytes. The relative density of different receptor subtypes was M3 > M5 > M4 > M2. The development of a reproducible technique for assaying muscarinic cholinergic receptor subtypes expressed by human peripheral blood lymphocytes may contribute to clarify their role in lymphocyte function.
In the last few years, Indol-3-pyruvic acid (IPA) has been subjected to 5 pilot clinical trials in volunteers and a phase II study on patients affected by anxiety, with or without sleep problems. Overall, results indicated a very good safety profile, relief from anxiety and a better quality of sleep in patients treated with IPA. Moreover, the drug showed no withdrawal signs, but positive effects on mood, improving feelings of relaxation, calmness and happiness. The mechanism of action of IPA, depending on increased turnover of some indoles in the CNS, appears clearly distinct from that of benzodiazepines, suggesting that the drug might be used in the treatment of symptoms of mild anxiety and stress experienced by busy and anxious people.
A multicenter study was carried out in 10 Italian Headache Centers to investigate the prevalence of psychosocial stress and psychiatric disorders listed by the IHS classification as the "most likely causative factors" of tension-type headache (TTH). Two hundred and seventeen TTH adult outpatients consecutively recruited underwent a structured psychiatric interview (CIDI-c). The assessment of psychosocial stress events was carried out using an ad hoc questionnaire. The psychiatric disorders that we included in the three psychiatric items of the fourth digit of the IHS classification were depressive disorders for the item depression, anxiety disorders for the item anxiety, and somatoform disorders for the item headache as a delusion or an idea. Diagnoses were made according to DSM-III-R criteria. At least one psychosocial stress event or a psychiatric disorder was detected in 84.8% of the patients. Prevalence of psychiatric comorbidity was 52.5% for anxiety, 36.4% for depression, and 21.7% for headache as a delusion or an idea. Psychosocial stress was found in 29.5% of the patients and did not differ between patients with and without psychiatric comorbidity. Generalized anxiety disorder (83.3%) and dysthymia (45.6%) were the most frequent disorders within their respective psychiatric group. The high prevalence of psychiatric disorders observed in this wide sample of patients emphasizes the need for a systematic investigation of psychiatric comorbidity aimed at a more comprehensive and appropriate clinical management of TTH patients.
One-hundred-and-twenty-eight young headache outpatients underwent an electromyographical (EMG) ischemic test and determination of Mg++ levels in red and mononuclear blood cells. In migraine patients, with and without aura (MwA and MwoA), Mg++ concentration in the erythrocytes and in mononuclear cells was significantly reduced compared to tension-type headache (TTH) patients and healthy controls (p < 0.0001). The EMG ischemic test was positive in 71% of migraineurs, but only in 9.5% of TTH patients. Low intra-erythrocyte and mononuclear cell levels were evident in 84.3% and 81.2% of migraine patients, respectively; those whose ischemic tests were positive had intra-erythrocyte and mononuclear cell levels of Mg++ below the norm, respectively. However, reduced levels of Mg++ in erythrocytes were found in only two patients with TTH, and in mononuclear cells in one patient with TTH. These data provide further confirmation of the role of Mg++ in determining the status of neuromuscular hyperexcitability in about two-thirds of migraine patients, including childhood and adolescence. They also support the validity of carrying out EMG ischemic testing for distinguishing this condition, which can be corrected with adequate oral Mg++ supplementation and with a possible positive impact on headache.
An alteration in serotonin concentration has been found in patients with chronic headache caused by abuse of analgesic substances as well as an up-regulation of 5HT2 platelet receptors, which has been correlated with chronicization of the headache. In a previous study we demonstrated an increase in L-arginine/nitric oxide (NO) pathway activity in platelets from patients affected by migraine with or without aura, particularly during attacks. In the present research we assessed the variations in platelet L-arginine/NO pathway and cyclic guanosine monophosphate (cGMP) levels in 32 patients affected by chronic daily headache (CDH) (8 M, 24 F, age range 34-50 years) both during and between attacks. In these same patients, the platelet aggregation to different collagen concentrations (0.3, 1, 3 micrograms/ml) was determined as well as the intracellular platelet calcium concentration using fluorescence polarization spectrometry. These parameters were compared with those of an age- and sex-matched control group (n = 25; n = 10, n = 15, age range 35-51 years). A reduction found in platelet aggregation response to each collagen concentration used (p < 0.001) was coupled with an increased NO and cGMP production (NO: p < 0.0001; cGMP: p < 0.001). This was accompanied by a significant increase in intracytosolic Ca2+ (p < 0.0001) concentration and a reduced platelet serotonin content compared to those in control individuals (p < 0.0002). Changes in the above platelet parameters were accentuated more in patients with analgesic abuse than in CDH patients with no drug abuse. These findings suggest the occurrence of an activation of cGMP-Ca2+ mediated events in CDH patients with analgesic abuse. This physiologic compensatory mechanism, which intervenes in overcoming the increase in cytosolic Ca2+ levels, is not as efficient at limiting serotonin depletion by platelet dense bodies. A similar depletion in the central serotoninergic pathway can be assumed in the same patients.
The aim of this research was to obtain an absolute quantification of the N-acetyl-aspartate, choline, creatine and phosphocreatine levels in normal-appearing white matter by means of 1H magnetic resonance spectroscopy in a group of multiple sclerosis patients (27 with the relapsing-remitting form and 13 with the secondary progressive form). These values were compared with those of a group of 12 age-matched healthy control subjects. A significant decrease in the N-acetyl-aspartate concentration was found in normal-appearing white matter of frontal and parietal brain areas in multiple sclerosis patients compared with the same areas in control subjects. This reduction was more evident in progressive patients. The decrease in the N-acetyl-aspartate concentration in normal-appearing white matter significantly correlated with the Expanded Disability Status and the lesional load. No significant change was found in the concentration of creatine or choline. This finding concurs with previous evidence of heterogeneity in the multiple sclerosis pathological process which is not confined to the lesions and involves not only myelin, but also axons, even in white matter which appears normal on MRI.
OBJECTIVE: To undertake a pilot study before conducting a large European multicentre prospective study, to determine the proportion of patients with atrial fibrillation who were not receiving antithrombotic treatment before stroke onset, and their characteristics. DESIGN AND PATIENTS: The stroke in atrial fibrillation ensemble (SAFE) I study was an observational study conducted in 213 patients with atrial fibrillation consecutively admitted in 1997 to three European centres for an acute stroke or transient ischaemic attack (TIA). It was determined whether they were receiving prior antithrombotic treatment. RESULTS: Atrial fibrillation was known before stroke in 148 patients (69.5%). Of 213 patients, 34 (16.0%) were receiving anticoagulation treatment before stroke, but only six had an international normalised ratio between 2. 0 and 3.5; 65 (30.5%) were receiving antiplatelet treatment; and three (1.4%) were receiving both anticoagulation and antiplatelet treatment. Of 137 patients eligible for oral anticoagulation, 108 (78.8%) did not receive treatment. Of 142 patients eligible for any antithrombotic treatment, 62 (43.7%) were not treated. The logistic regression analysis, assuming anticoagulation treatment as a dependent variable, found digoxin treatment, absence of arterial hypertension, mitral stenosis, and cardioversion as independent factors. Assuming any antithrombotic treatment as a dependent variable, previously known atrial fibrillation, lower age, being a non-smoker, and absence of arterial hypertension were found to be independent factors. CONCLUSION: More than half of the patients with atrial fibrillation admitted for acute stroke or TIA were not receiving any antithrombotic treatment beforehand. New onset atrial fibrillation and contraindications account for a minority of non-prescriptions; thus, other reasons should be identified to improve stroke prevention in the community.
The activity of the acidic glycohydrolase beta-N-acetylhexosaminidase, an enzyme system normally participating in the stepwise degradation of glycoproteins, glycolipids, and proteoglycans, appears to be modulated in lymphocytes and monocytes from peripheral blood of patients affected by multiple sclerosis during different stages of the disease. In particular, a significant decrease in this enzyme activity, compared with healthy subjects, was observed in patients affected by the relapsing-remitting form both in a stable clinical status and during a relapse as well as in patients with the progressive form. The decrease in total intracellular hexosaminidase activity in lymphomonocytes of multiple sclerosis patients was accompanied by an enrichment of this activity associated with the plasma membrane fraction as demonstrated by experiments of subcellular fractionation. The analysis carried out using two synthetic substrates, 4-methylumbelliferyl N-acetyl-beta-D-glucosaminide and its sulfate derivative, enables us to demonstrate that this accumulation is mainly due to isoenzymes with a betabeta structure, whereas lysosomal fractions confirmed the classical presence of both alphabeta and betabeta forms (hexosaminidases A and B, respectively). This was particularly evident in the plasma membrane fraction from mononuclear cells of patients with a clinical exacerbation of the disease. Considered together, these observations provide additional insight into the abnormality of peripheral blood immune cells in multiple sclerosis and may contribute to the understanding of the basic mechanisms underlying the pathological events resulting in the demyelinating process.
BACKGROUND: In vivo magnetic resonance spectroscopy (MRS) has been widely used to assess biochemical changes which occur in demyelinating lesions in white matter of patients with multiple sclerosis. It has been suggested that metabolic variations evidenced by MRS are sensitive indicators of the effects of immunomodulatory treatments in this disease. Given the recent finding of an increase in the disease activity in patients with multiple sclerosis treated with interferon (IFN) beta-1a in the first period of treatment,1H MRS was used to investigate further the modification in brain metabolic indices, particularly in the first phase of IFN beta treatment. METHODS: A 1H MRS study was performed on five patients with relapsing-remitting multiple sclerosis who were being treated with intramuscular IFN beta-1a (6 million units/week) for six months and on five untreated patients. The mean age, duration of the disease, and expanded disability status scores (EDSS) of the two groups were similar. Patients were evaluated at the beginning of the study and in the first, third, and sixth months of treatment. RESULTS: In the multiple sclerosis white matter lesions, N-acetylaspartate (NAA), choline (Cho), inositol (Ins), and creatine (Cr) peaks did not vary significantly over the entire period of the study in the untreated group. In the treated group there was a significant increase in the Cho peak area at the first month compared with the pretreatment period, and this increase continued in the third and sixth months (p<0.001). A slight but not significant rise in the Cho peak was also found in normal appearing white matter in the patient group undergoing treatment with IFN beta-1a. The increase in Cho and the lack of significant changes in Cr and NAA peaks induced a significant rise in Cho/Cr and Cho/NAA ratios over the entire period of treatment compared with those at the beginning of the study (p<0.02 and p<0.005 respectively). In the treated group there was a slight but significant increase in the Ins peak in the first month (p<0.05) but in the third and sixth months of treatment the Ins values returned to the pretreatment range. CONCLUSIONS: IFN beta-1a has an impact on metabolite concentrations in multiple sclerosis lesions measured by proton MRS. The increase in Cho, Cho/NAA, and Cho/Cr ratios in multiple sclerosis lesions reinforces the view that they are an index of active or recent demyelination and could support the clinical, neuroradiological and immunological evidence showing an increase in disease activity during the first period of treatment with IFN beta-1a. On the other hand, the increase in the Cho peak could be indicative of a rise in membrane turnover in multiple sclerosis lesions or a remodelling of plaques which is not necessarily due to a de novo immune mediated demyelination.
The activity of the Golgi glycosyltransferase beta1,6 N-acetylglucosaminyltransferase (core 2 GlcNAc-T), which plays a role in T-cell activation and cell-cell adhesion, appears to be modulated in resting lymphomonocytes during different phases of multiple sclerosis (MS). In particular, a significant decrease (25-30%) of the enzyme activity was observed, with respect to healthy subjects, in MS patients who were in relapse or in the very early stages of remission. A similar trend was found to be associated with patients affected by active lesions. A statistically significant decrease in the enzyme activity was also observed in patients with the progressive form. By contrast, core 2 GlcNAc-T activity did not appear correlated with duration of the disease. Interestingly, MS individuals under treatment with IFN-beta1a, an immunosuppressive agent, showed levels of activity which were comparable with those observed in healthy subjects. Together, these observations suggest that down-regulation of core 2 GlcNAc-T activity is linked to the occurrence of acute phases in the relapsing-remitting form and to the progressive form of the disease, probably caused by altered expression of glycoproteins which are involved in lymphomonocyte activation and/or interaction with the endothelium. Additionally, it appears that the enzyme assay may provide a useful marker of the disease activity and the effects of therapeutical approaches.
Several experimental findings suggest a potential role of excessive nitric oxide (NO) production by macrophages, microglia and astrocytes in the pathogenesis of demyelinating lesions in MS. We assessed the production of nitrites by peripheral blood mononuclear cells (PBMCs) of 15 MS patients (10 F and 5 M) with the R-R form (EDSS: 1-3.0) and in 15 age-matched control subjects. 9 out of the 15 MS patients showed active lesions in MRI at the time of examination. 7 patients were also monitored at the onset, during and following a clinical relapse. Secretion of cytokines by PBMCs was assessed at the basal time and after 24 h of incubation with lipopolysaccharide (LPS). The production of nitrites in the supernatants of PBMCs stimulated and not stimulated with lipopolysaccharide was evaluated. The secretion of IL1 beta, IFN-gamma, TNF-alpha, IL-6 IL-10 and TGF-beta by PBMCs was detected using ELISA methods. The production of NO, both basal and stimulated, was significantly higher in the patients with active lesions than in those without active lesions (p < 0.01). No significant difference was evident between the basal and LPS-stimulated production of NO between control subjects and MS patients without active lesions. During relapses there was a significant increase in NO production by PBMCs compared to the clinical stable stage of the disease (p < 0.0001). This increase was significantly greater in the early stage of relapse than in the late stage (p < 0.04). A decline of NO levels was observed during recovery. Steroid treatment induced a significant decrease in the PBMC NO production of MS patients during exacerbations (p < 0.01). The levels of IL-1 beta, IFN-gamma and TNF-alpha are significantly higher in the supernatants of the PBMCs which produced greater amounts of NO (p < 0.02, p < 0.03, p < 0.01, respectively). On the other hand, NO levels were negatively related to IL-10 and TGF-beta production (R = -75, p < 0.0001 and R = -0.79, p < 0.0001, respectively). The increase production of NO by peripheral blood mononuclear cells demonstrated in our study to be associated with increased production of proinflammatory cytokines could therefore be considered to be a marker of mononuclear cell activation in the peripheral blood of MS patients and, indirectly, of disease activity. Its increased secretion during T cell and monocyte homing in the CNF could contribute to the damage to the blood-brain barrier and the subsequent cytokine-mediated cytotoxic effect to myelin and oligodendrocytes in the white matter of MS patients.
The pressure pain threshold of 30 patients affected by tension-type headache was assessed and the values compared with those of a group of 30 age-matched control subjects. In the patient group, pressure pain threshold values were related to the blood cell concentration of some neurotransmitters which are considered to be involved in the genesis and modulation of pain (beta-endorphin levels in peripheral blood mononuclear cells [PBMCs], substance P and serotonin concentrations in platelets). The pressure pain threshold was significantly lower in tension-type headache patients than in control subjects (P < 0.0006). Significantly lower levels of beta-endorphins in PBMCs and substance P in platelets, as well as significantly higher levels of serotonin in platelets were found in tension-type headache patients compared to the control subjects (P < 0.0001). A significant positive correlation was found between pressure pain threshold values and beta-endorphin levels in both control and patient groups (P < 0.0001). On the contrary, a statistically significant negative correlation was evident between pressure pain threshold values and substance P levels in platelets in both patients and control subjects (P < 0.01 and P < 0.001, respectively). In both groups, there was a negative correlation between beta-endorphins in PBMCs and substance P in platelets (patients P < 0.02, controls P < 0.001). The findings of altered beta-endorphin levels in blood mononuclear cells and substance P levels in platelets could be the peripheral biochemical reflection of the low pressure pain threshold values in tension-type headache patients, and support the hypothesis of an impairment of the antinociceptive systems in this form of headache.
Previous studies have reported the existence of an arginine/nitric oxide (NO) pathway and the involvement of a Ca2+, NADPH-dependent nitric oxide synthase enzyme (NOS) in the generation of NO in human platelets. In the present research, we determined the rate of production of NO and cGMP in the cytosol of platelets stimulated by collagen in 20 females with menstrual migraine (MM), (age range 24-40 years), assessed in the follicular and luteal phases, interictally and ictally in the latter period. The same patients were also assessed at mid-cycle. At the same time, the variations in the collagen response of platelets were evaluated. Moreover, these parameters were determined in the same periods in 20 age-matched control females and in 20 females affected by non-menstrually related migraine (nMM). The collagen-stimulated production of NO in the cytosol of the platelet cytosol was significantly higher in migraine patients with MM than in the control subjects. In MM patients, the increase was greater in the luteal phase of the cycle than during the follicular phase (p < 0.005). A rise in NO production in platelets was also present, although to a lesser extent, in females affected by nMM compared to the healthy females, but this rise was most evident at ovulation (p < 0.001). A slight but significant increase was also observed at mid-cycle in control women, but this increase did not reach the values determined in the migraine groups (p < 0.02). NO production in platelets stimulated by collagen was significantly increased during attacks with respect to the interictal period in both patient groups. Similar variations were observed in the production of cGMP in MM and nMM patients. The increase in NO production was accompanied by a decrease in platelet aggregation in the migraine groups compared with the control group; this decrease was most evident at mid-cycle in nMM patients and in the luteal phase in MM patients. These data suggest an activation of the L-arginine/ NO pathway in MM and nMM patients which could explain the modifications in the platelet response to collagen evidenced in migraine-free periods and during attacks. The activation of this pathway is more accentuated in the luteal phase in MM patients, and this could be the cause of the increased susceptibility to migraine attacks in perimenstrual and menstrual periods in these patients.
Headache has often been described in the hyperexcitability syndrome which recognizes an alteration of calcium and magnesium status in its etiopathogenesis. Moreover, in migraine patients magnesium has been shown to play an important role as a regulator of neuronal excitability and, therefore hypothetically, of headache. The present research involves a neurophysiological evaluation and magnesium status assessment of a group of headache patients. Nineteen patients (15 women and 4 men) with episodic tension-type headache and 30 patients (27 women and 3 men) with migraine without aura were examined. An ischemic test was carried out on the right arm with electromyographic (EMG) recording of motor unit potential activity during the interictal period. The determination of extracellular (serum and saliva) and intracellular (red and mononuclear blood cells) magnesium was also performed. The EMG test was positive in 25 of 30 migraine patients and in 2 of 19 tension-type headache patients. Between the two patient groups, there were no significant variations in the concentration of extracellular and white blood cell magnesium, while the red blood cell concentration of this mineral in the group of migraineurs was significantly reduced with respect to that in the group of tension-type headache patients (P < 0.05). The positive EMG test was significantly associated with a low concentration of red blood cell magnesium (P < 0.0001). These results confirm previous findings by demonstrating different etiopathogenic mechanisms as the basis of migraine and tension-type headache. Migraine seems to be related to an altered magnesium status, which manifests itself by a neuromuscular hyperexcitability and a reduced concentration in red blood cells.
Nitric oxide (NO) in platelets has been proposed as a promising tool for studying NO variations in migraine. In the present research the platelet response to collagen and the basal and collagen-induced production of NO and cGMP in platelet cytosol were assessed in migraine patients (25 with aura and 35 without aura) both interictally and ictally, and compared with the same parameters in 30 age-matched control subjects. A reduced responsiveness to collagen was found in migraine patients, particularly those with aura, and this was more marked during attacks (ANOVA interictal periods: p < 0.01, attacks: p < 0.02) The basal and collagen-stimulated production of NO and cGMP in the platelet cytosol was significantly higher in migraine patients with aura assessed in interictal periods than in control subjects, and this production was further increased during attacks (interictal period: NO ANOVA: p < 0.001, ictal period: p < 0.01; cGMP: interictal period p < 0.01, ictal period: p < 0.02). The increase in platelet NO and cGMP production was also evident, though to a lesser extent, in migraine patients without aura. The present research supports the hypothesis of an activation of the L-arginine/NO pathway in migraine patients, especially those with aura, and confirms the findings of a previous study of increased levels of L-arginine in platelets of migraine patients studied in headache free-periods, and decreased collagen aggregation in whole blood.