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Biomedical subjects

D D Mitsikostas

Publications and source records attributed to D D Mitsikostas.

At least 19 recordsLinked to original sources
PubMed2006

Methodology of clinical trials in multiple sclerosis.

The scope of the paper is to summarise key issues in methodology used in clinical trials on multiple sclerosis (MS) treatment and help clinicians to better understand articles reporting the results of these trials. Relapsing ratio and disability progression based on the Expanded Disability Status Scale are currently used as clinical efficacy primary outcomes, but more global measurements should be used in future such as the MS Functional Composite. For magnetic resonance imaging (MRI) outcomes, new MRI composites and indexes are already available (Z4 score, conventional MRI-derived end-points) that, together with new MRI techniques (magnetisation- transfer MRI and proton resonance spectroscopy), offer more precise neuroimaging assessments of the disease. These efficacy measurements should be presented in articles as number needed to treat, which assists the reader to calculate and compare the treatments' power and safety.

Clinical Trials as Topic↗
PubMed2006

Animal models of migraine: looking at the component parts of a complex disorder.

Animal models of human disease have been extremely helpful both in advancing the understanding of brain disorders and in developing new therapeutic approaches. Models for studying headache mechanisms, particularly those directed at migraine, have been developed and exploited efficiently in the last decade, leading to better understanding of the potential mechanisms of the disorder and of the action for antimigraine treatments. Model systems employed have focused on the pain-producing cranial structures, the large vessels and dura mater, in order to provide reproducible physiological measures that could be subject to pharmacological exploration. A wide range of methods using both in vivo and in vitro approaches are now employed; these range from manipulation of the mouse genome in order to produce animals with human disease-producing mutations, through sensitive immunohistochemical methods to vascular, neurovascular and electrophysiological studies. No one model system in experimental animals can explain all the features of migraine; however, the systems available have begun to offer ways to dissect migraine's component parts to allow a better understanding of the problem and the development of new treatment strategies.

Animals↗
PubMed2005

Add-on topiramate in the treatment of refractory partial-onset epilepsy: clinical experience of outpatient epilepsy clinics from 11 general hospitals.

An open, prospective, observational study was performed to assess efficacy and adverse-event profile of topiramate as add-on therapy in epilepsy. Outpatient neurology clinics from 11 general hospitals in Greece participated in the study. In total, 211 patients with treatment resistant partial-onset seizures who met the inclusion criteria, were studied. After baseline evaluation, topiramate was given at a target dose of 200mg/day over a 1-month titration period. In the subsequent maintenance period, the topiramate dose could be varied according to the clinical results. Patients were followed for in total 6 months, with monthly visits and regular physical, neurological and laboratory examinations. Seizure frequencies decreased to 35--40% of baseline values following 3 months of treatment and remained relatively constant thereafter. The average monthly seizure frequency over the 6-month study period was 4.61, compared to 9.21 at baseline. The number of responders (patients with at least 50% reduction in seizure frequency) followed a similar pattern, i.e., increase during the first 3 months levelling off at a final 80--85% response rate. Of those completing the study, 30% had been seizure-free for at least 3 months and 12% for 5 months. Topiramate was well tolerated, no deviations in laboratory values were found. Adverse events appeared to occur less frequently, and antiepileptic effects were more pronounced in this prospective open-label study than in earlier reports from randomised controlled trials. The nature of the patient population and the application of individualised dose optimisation are proposed as contributing factors to explain the favourable results of this study.

Adolescent↗
PubMed2005

Time perception in migraine sufferers: an experimental matched-pairs study.

Despite occasional case reports, the influence of migraine on time perception has not been systematically investigated. We used an experimental technique to study the estimation of auditory duration in 40 migraineurs at different tone intervals in the ms and in the 1-s range and compared their performance with 40 matched normal subjects. With a time awareness questionnaire we also evaluated the subjective experience of elapsing time for long durations involving long-term memory processes. Migraine did not influence temporal judgements in either of the tests, suggesting that migraineurs do not generally over- or underestimate temporal events. The subgroup of migraineurs with a depressive disorder, however, showed a marked speeding up of their internal timekeeping mechanisms, pointing to depression as an important covariable in time perception.

Acoustic Stimulation↗
PubMed2002

5-Hydroxytryptamine(1B/1D) and 5-hydroxytryptamine1F receptors inhibit capsaicin-induced c-fos immunoreactivity within mouse trigeminal nucleus caudalis.

In order to investigate the c-fos response within the trigeminal nucleus caudalis (Sp5C) after noxious meningeal stimulation, capsaicin (0.25, 0.5, 1 and 5 nmol) was administered intracisternally in urethane (1 g/kg) and alpha-chloralose (20 mg/kg) anaesthetized male mice. Capsaicin induced a robust and dose-dependent c-fos-like immunoreactivity (c-fos LI) within Sp5C. C-fos LI was observed within laminae I and II of the entire brain stem from the area postrema to C2 level, being maximum at the decussatio pyramidum level. The area postrema, solitary tract, medullary and lateral reticular nuclei were also labelled. The 5-hydroxytryptamine(1B/1D/1F) receptor agonist sumatriptan (0.01, 0.1, 1 and 10 mg/kg), administered intraperitoneally 15 min before capsaicin stimulation (1 nmol), decreased the c-fos response within Sp5C, but not within solitary tract. The novel specific 5-hydroxytryptamine1F agonist LY 344864 (0.1 and 1 mg/kg, i.p.) significantly decreased the c-fos LI within the Sp5C as well. These findings suggest that intracisternally administered capsaicin activates the trigeminovascular system and that the pain neurotransmission can be modulated by 5-hydroxytryptamine(1B/1D/1F) receptors in mice. Thus, the availability of this model in mice, taken together with the possibility of altering the expression of specific genes in this species, may help to investigate further the importance of distinct proteins in the neurotransmission of cephalic pain.

Anesthetics, General↗
PubMed2001

Receptor systems mediating c-fos expression within trigeminal nucleus caudalis in animal models of migraine.

In intracranial structures unmyelinated C- and Adelta-fibers of the trigeminal nerve transmit pain stimuli from meninges to the trigeminal nucleus caudalis (Sp5C). Peripheral nerve endings surround meningeal vessels (the so-called trigeminovascular system) and contain vasoactive neuropeptides (calcitonin gene-related peptide, substance P and neurokinin A). Activation of the trigeminovascular system promotes a meningeal sterile inflammatory response through the release of neuropeptides by peripheral endings. Orthodromic conduction along trigeminovascular fibers transmits information centrally with induction of immediate early c-fos gene within post-synaptic Sp5C neurons, as a marker of neuronal activity within central nociceptive pathways. In laboratory animals the system is activated by either electrical stimulation of the TG, chemical stimulation of the meninges, electrical or mechanical stimulation of the superior sagittal sinus or by induction of cortical spreading depression. All these techniques induce c-fos within Sp5C and are used as a rodent/feline model of vascular headache in humans. Up-to-date there is evidence that at least ten receptors (5-HT(1B), 5-HT(1D), 5-HT(lF), 5-HT(2B), NK-1, GABA(A), NMDA, AMPA, class III metabotropic glutamate receptors, and opioids mu receptors) modulate c-fos expression within Sp5C. These receptors represent potential targets for anti-migraine drugs as shown by triptans (5-HT(1B/1D/1F)) and ergot alkaloids (5-HT(1A1B/1D/1F)). This review discusses the importance of c-fos expression within Sp5C as a marker of cephalic nociception, the different cephalic pain models that induce c-fos within Sp5C, the receptors involved and their potential role as targets for anti-migraine drugs.

Animals↗
PubMed1999

Both 5-HT1B and 5-HT1F receptors modulate c-fos expression within rat trigeminal nucleus caudalis.

A possible mechanism of action of antimigraine drugs such as sumatriptan is inhibition of the trigeminovascular pathway. Sumatriptan's effects might be mediated by 5-HT1B, 5-HT1D or 5-HT1F receptors. To establish the relative importance of these subtypes, we compared the effects of sumatriptan with those of a selective 5-HT1F receptor agonist (LY 344864) on c-fos protein expression in the trigeminal nucleus caudalis. c-fos expression was induced in urethane-anaesthetized rats by intracisternal capsaicin administration. Sumatriptan and LY 344864 decreased the number of capsaicin-induced c-fos-like immunoreactive cells within trigeminal nucleus caudalis (ID50 = 0.04 and 0.6 mg kg(-1)). The effect of sumatriptan, but not of LY 344864, was prevented by pretreatment with the antagonist SDZ 21-009, which displays high affinity for rat 5-HT1B receptors. LY 344864 appears to attenuate c-fos-like immunoreactivity via 5-HT1F receptors, while sumatriptan acts via 5-HT1B receptors. The fact that activation of 5-HT1F receptors is sufficient to modulate the activity of the trigeminal system suggests that this receptor may be a target for antimigraine drugs with improved safety profile.

Adrenergic beta-Antagonists↗
PubMed1999

Non-NMDA glutamate receptors modulate capsaicin induced c-fos expression within trigeminal nucleus caudalis.

1. We examined the effects of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor antagonists 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzol[f]quinoxaline-7-sulpho namide (NBQX), the kainate receptor antagonists gamma-(R-)-glutamylaminomethanesulphonic acid (GAMS) and 6,7,8,9-tetrahydro-5-nitro-1H-benz[g]indole-2,3-dione-3-oxime (NS-102), and the group III metabotropic glutamate receptor (mGluR) agonist 2-amino-4-phosphono-S-butanoic acid (L-AP4) on c-fos-like immunoreactivity (c-fos LI) in trigeminal caudalis (Sp5C), lateral reticular (LRt), medullary reticular (Md) and solitary tract (Sol) nuclei, after intracisternal injection of capsaicin in urethane anaesthetized Sprague-Dawley rats. 2. Few c-fos labelled cells were observed within Sp5C in capsaicin-vehicle treated animals. The number of positive c-fos cells increased by 17 fold after intracisternal capsaicin (5 nmol) administration. 3. Pretreatment with CNQX (0.02, 0.1, 0.6, 3 and 15 mg kg-1) or NBQX (0.01, 0.1 and 1 mg kg-1), administered intraperitoneally 15 min before capsaicin, significantly reduced labelled cells within Sp5C by a maximum of 45 and 34%, respectively. The number of c-fox LI cells within LRt, Md and Sol was not affected. Pretreatment with L-AP4 (1, 3 and 10 mg kg-1) decreased the number of Sp5C c-fos LI cells by a maximum of 30%, whereas GAMS (1 and 10 mg kg-1) and NS-102 (1 and 5 mg kg-1) did not show any significant effect. 4. These results suggest that blockade of AMPA receptors, but not kainate receptors, or the activation of group III mGluRs, decrease the response of Sp5C neurons to trigeminovascular activation. Thus, in addition to NMDA receptors, mGluRs and AMPA receptors may modulate cephalic pain and may provide a potential therapeutic target for antimigraine drugs.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1999

Comorbidity of headache and depressive disorders.

The goal of the present study was to investigate the clinical profile of patients with primary headache syndromes who also suffer from mood disorders. Four-hundred-and-seventy headache outpatients (170M, 300F) and 150 age- and sex-matched healthy subjects were screened using a specific questionnaire that included the Hamilton rating scales for anxiety and depression. The average scores of the Hamilton rating scales for anxiety and depression were significantly higher in headache sufferers (17.4 and 14.2, respectively) than in healthy people (6.8 and 5.7, respectively). The frequency of headache attacks, the history of headaches, and gender (women more than men) were correlated with the score of the Hamilton rating scale for both anxiety and depression. Sixteen headache patients (3.4%) achieved the DSM-IV criteria for major depression or dysthymia versus one among headache-free subjects (0.6%; OR 5.2). Patients suffering from drug-overuse and migraine with aura showed the higher odds ratios (35 and 17, respectively). These results suggest that those headache patients with long history and high frequency of headaches, or patients suffering from migraine with aura and drug-overuse might benefit from psychiatric evaluation.

Adult↗
PubMed1999

Perfusion weighted imaging during migraine: spontaneous visual aura and headache.

Using perfusion weighted imaging, we studied 28 spontaneous migraine episodes; 7 during visual aura (n = 6), 7 during the headache phase following visual aura (n = 3), and 14 cases of migraine without aura (n = 13). The data were analyzed using a region-of-interest-based approach. During aura, relative cerebral blood flow (rCBF) was significantly decreased (27% +/- 0.07) in occipital cortex contralateral to the affected hemifield. rCBV was decreased (15% +/- 0.12) and mean transit time increased (32% +/- 0.3), persisting up to 2.5 h into the headache phase. Other brain regions did not show significant perfusion changes. During migraine without aura, no significant hemodynamic changes were observed. In one patient who experienced both migraine with and without aura, perfusion deficits were observed only during migraine with aura. These findings suggest that decremental blood flow changes in occipital lobe are most characteristic of migraine with aura.

Adult↗
PubMed1998

Fasciculation potentials in healthy people.

The aim of this study was to investigate the fasciculation potentials (FPs) in the small-peripheral muscles of the foot and hand and the possible associated factors, in a healthy population. One hundred-twenty-two normal individuals (65 men and 57 women), aged 17-67 years (mean 39.96, SD=12.76) participated in the study. A special questionnaire consisting of 47 questions was devised as the basic instrument of the interview, which included the Hamilton anxiety rating scale. The extensor digitorum brevis (EDB), the flexor hallucis brevis (FHB) and the first dorsal interosseous (FDI) muscles were studied bilaterally using surface electrodes. In 94 (58 men and 36 women) from 122 participants (65 men and 57 women) FPs were recorded (men 89.2%, women 63.1%, all 77%). The mean FPs per minute and muscle, in all three muscles, was 8.0 (SD=4.6). More FPs were recorded in the muscles of foot than in FDI (p<0.01) and in FHB than in EDB (p<0.001). FPs were correlated to gender, body height and weight and to the score of the Hamilton scale (r2>0.1, p<0.01). The syndrome of benign FPs was observed in 2 men (1.6% of men). These results suggest that FPs are a very common phenomenon in the peripheral muscles of healthy persons.

Action Potentials↗
PubMed1998

The NMDA receptor antagonist MK-801 reduces capsaicin-induced c-fos expression within rat trigeminal nucleus caudalis.

The effect of the N-methyl-D-aspartate (NMDA) receptor antagonist (5R, 10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclo-hepten-5,10-i mine hydrogen maleate (MK-801) was examined on c-fos-like immunoreactivity (c-fos-LI) in urethane-anesthetized Sprague-Dawley rats using a polyclonal antibody. C-fos, an indicator of neuronal activation, was assessed within the trigeminal nucleus caudalis (TNC), area postrema. lateral reticular and solitary tract nuclei 2 h after intracisternal injection of capsaicin. C-fos-positive cells were counted at three representative levels corresponding to obex, -2.05 mm and -6.45 mm in 18 tissue sections (50 microm). A weighted average was obtained reflecting total brainstem expression within lamina I, II of TNC using a recently validated method. Capsaicin (0.1, 1, 5, 10 and 15 nmol) caused a dose-dependent labeling of cells in lamina I, II at obex similar to that previously reported after intracisternal blood or carrageenin administration in rats and guinea pigs. MK-801 (0.3, 1 and 3 mg/kg) administered i.p. 30 min before capsaicin (5 nmol in 100 microl artificial CSF) reduced significantly and dose-dependently (12%, 36% and 47%, respectively) the c-fos-LI cells in TNC at each level from rostral to caudal but not in solitary tract, area postrema and lateral reticular nuclei, and for unexplained reasons, increased c-fos-LI within the inferior olive. These results suggest that NMDA receptors provide a potential therapeutic target for cephalic pain (e.g. migraine) due to trigeminovascular activation from meningeal afferents.

Animals↗
PubMed1998

Headache in systemic lupus erythematosus: a controlled study.

Intractable headaches, the so-called 'lupus headaches', have been long thought of as a common and characteristic manifestation of systemic lupus erythematosus (SLE). Seventy-eight patients with SLE, including 10 patients with definite central nervous system (CNS) involvement, and 89 healthy individuals matched for age, sex and socioeconomic status, were studied by a specific questionnaire addressing the characteristics and type of headache. Clinical features of SLE, neurological manifestations and treatment, disease severity and autoantibody profiles were correlated to the presence of headache. One year prevalence of headache was similar between patients (32%) and otherwise healthy individuals (30%). No significant differences regarding frequency, family history of headache and need for analgesic medication were observed. Headache refractory to analgesic treatment, but responsive to corticosteroid regimen, was recorded in only one patient. Clinical and serological features of SLE, including Raynaud's phenomenon and the presence of anticardiolipin antibodies, were not significantly different between headache sufferers and non-sufferers. In the majority of patients reporting headache, anxiety and/or depression co-existed. Episodic tension headache was the most frequent type, while migraine was traced in a quarter of headache sufferers. Neither the presence nor the clinical type of headache was related to, or predictive of, the development of seizures or psychosis. These results indicate that headache is not specifically related to SLE expression or severity, and suggest that accepting the presence even of a severe headache as a neurological manifestation of SLE in the absence of seizures or overt psychosis may result in overestimation of the disease status.

Adult↗
PubMed1997

Buspirone vs amitriptyline in the treatment of chronic tension-type headache.

OBJECTIVES: The aim of this study was to explore the efficacy of buspirone (BSR), in comparison with amitriptyline (AML) in the prophylactic treatment of chronic tension-type headache (CTH), in an open and randomized clinical trial. MATERIAL AND METHODS: Twenty-six CTH patients (10 men and 16 women) were treated with BSR (30 mg daily) for 12 weeks. A parallel group of 32 CTH patients (12 men and 20 women) was treated with AML (50 mg daily). The major clinical parameters evaluated were the headache index (days with headache per month), the frequency of drug use for the acute management of headaches, the patients' opinion for the treatment and the Hamilton anxiety and depression rating scales. RESULTS: During the study 9 patients dropped out (4 from the BSR group and 5 from the AML group). Twelve (54.4%) patients from the BSR group responded to treatment (> 50% reduction in the headache index), compared to 17 (60.7%) from the AML group. In the BSR group, 14 (53.8%) patients reported various mild side effects (nausea most frequently), vs 21 (65.5%) of the AML group (mouth dryness more frequently). Patients treated with AML had better opinion and used less drugs for the acute treatment of headaches than the BSR treated patients. CONCLUSION: These results suggest that BSR may be effective in the prophylactic treatment of CTH, and that further investigation in a placebo controlled study is needed.

Adult↗
PubMed1996

The effect of sumatriptan on brain monoamines in rats.

Clinical data suggests that sumatriptan is effective in the acute treatment of migraine. The vascular effects of the drug have been invoked to explain this antimigraine efficacy. However, the effect of sumatriptan on brain monoamines has not previously been investigated. In order to study these hypothetical effects, we administered the drug to 24 male rats, subcutaneously, at three doses (0.3, 0.6, and 0.9 mg/kg of body weight), and 30 minutes later, all animals were decapitated. Dopamine, serotonin, and their metabolites 3,4 dihydroxyphenylacetic acid, 5-hydroxyindoleacetic acid, and homovanillic acid concentrations were measured in the frontal cortex, hypothalamus, striatum, and hippocampus, by high performance liquid chromatography. Plasma concentrations of the drug were also determined. The control group was treated with NaCl 0.9%, given subcutaneously. Sumatriptan, at the dose of 0.3 mg/kg did not alter the brain monoamine concentrations; however, at the dose of 0.6 mg/kg, sumatriptan decreased serotonin concentration in the hypothalamus and increased the turnover of dopamine and serotonin in the hypothalamus and striatum, while at the dose of 0.9 mg/kg, it augmented only the turnover of serotonin in the hypothalamus. No dose-dependent effect of the drug was found. This subcortical antidopaminergic and antiserotoninergic effect of sumatriptan may be involved in its antimigraine action.

3,4-Dihydroxyphenylacetic Acid↗