PubMed Health⌕ Search

Biomedical subjects

M Diomedi

Publications and source records attributed to M Diomedi.

At least 19 recordsLinked to original sources
PubMed2005

Sildenafil increases cerebrovascular reactivity: a transcranial Doppler study.

The authors performed a double-blind, placebo-controlled study in 28 patients to evaluate the effects of sildenafil on cerebral hemodynamics. A significant improvement of cerebrovascular reactivity, without any modification of other variables, was recorded 1 hour after the administration of 50 mg sildenafil. Further investigations are needed to evaluate whether cerebrovascular reactivity improvement could contribute to triggering sildenafil-induced migraine.

Aged↗
PubMed2005

Acanthocytosis as a predisposing factor for non-ketotic hyperglycaemia induced chorea-ballism.

BACKGROUND: Episodic non-ketotic hyperglycaemia in patients with diabetes may be responsible for a syndrome characterised by hemichorea-hemiballism associated with unique radiological features. OBJECTIVE: To investigate whether factors other than hyperglycaemia may be responsible for the neurological involvement. METHODS: Three patients who developed a persistent chorea-ballism syndrome triggered by a hyperglycaemic crisis were investigated. In these patients, the persistence of the involuntary movements required neuroleptic medication. RESULTS: T1 weighted magnetic resonance imaging revealed bilateral hyperintense lesions involving the striatum. Surprisingly, in these patients, the laboratory investigations revealed peripheral red blood cell acanthocytosis in a significant proportion of cells. CONCLUSION: Compared with the large population of patients with diabetes who do not show abnormal involuntary movements, unrecognised acanthocytosis in diabetes might render patients prone to develop hemichorea-hemiballism.

Aged↗
PubMed2004

CagA-positive Helicobacter pylori strains may influence the natural history of atherosclerotic stroke.

OBJECTIVE: To test the hypothesis that infection with virulent cytotoxin-associated gene-A (CagA)-bearing Helicobacter pylori strains influences the atherosclerotic process and the clinical course in atherosclerotic stroke patients. METHODS: ELISA was used to assess the seroprevalence of infection by H. pylori and CagA-positive strains in 185 patients. Intima-media thickness (IMT) was determined by Doppler ultrasound. Baseline, 1-week, and 1-month NIH Stroke Scale (NIHSS) scores were used to evaluate the short-term clinical course. RESULTS: H. pylori infection was found in 79% of patients; 58% of these tested positive for CagA. IMT was higher among CagA-positive patients than among CagA-negative ones (1.13 +/- 0.26 mm vs 0.97 +/- 0.15 mm; univariate analysis, p = 0.0001; multivariate analysis, odds ratio [OR], 2.36; 95% CI, 1.57 to 3.54; p = 0.0001) or H. pylori-negative ones (1.01 +/- 0.17 mm; univariate analysis, p = 0.007; multivariate analysis, OR, 1.90; 95% CI, 1.22 to 2.97; p = 0.005). CagA-positive patients had poorer initial outcomes based on serial measurements of the NIHSS score (repeated measures analysis of variance, p < 0.0001). No significant difference in IMT and NIHSS score was found between H. pylori-positive and H. pylori-negative patients. CONCLUSIONS: Infection with cytotoxin-associated gene-A-positive Helicobacter pylori strains in atherosclerotic stroke patients is associated with greater intima-media thickness and poorer short-term outcome compared with cytotoxin-associated gene-A-negative patients.

Aged↗
PubMed2002

Carotid artery intima-media thickness and lacunar versus nonlacunar infarcts.

BACKGROUND AND PURPOSE: Increases in the thickness of the intima and media of the carotid artery have been associated with an increased risk of myocardial infarction and stroke in subjects without a history of cardiovascular disease. Lacunar infarcts, one of the most common subtype of ischemic stroke, show unique pathological and clinicoradiological characteristics. The present study examines the relationship between vascular risk factors, including carotid artery intima-media thickness (IMT), and lacunar versus nonlacunar infarcts. METHODS: We collected data from patients with acute ischemic stroke admitted to hospital. Patients and 129 control subjects underwent B-mode ultrasonographic measurements of IMT of the common carotid artery. We examined the association of lacunar and nonlacunar infarcts with age, sex, and potential vascular risk factors. RESULTS: Of 292 adult patients with an acute first-ever ischemic stroke, 96 were considered lacunar and 196 were considered nonlacunar strokes. We did not find a significantly different percentage of diabetes, smoking, hypertension, dyslipidemia, myocardial infarction, and previous transient ischemic attack between the 2 groups of patients. The multinomial logistic regression procedure selected carotid artery IMT and atrial fibrillation as the only independent factors able to discriminate between lacunar and nonlacunar patients. IMT values were significantly higher in patients with nonlacunar stroke versus both those with lacunar stroke and control subjects. CONCLUSIONS: The present results indicate the usefulness of noninvasive measurement of IMT with ultrasonic techniques as a diagnostic tool that may help to identify different subtypes of ischemic stroke patients. The noninvasive measurements may have predictive power with respect to lacunar versus nonlacunar infarcts.

Acute Disease↗
PubMed2001

Influence of physiologic oscillation of estrogens on cerebral hemodynamics.

The interactions between estrogens and the cerebrovascular system are complex and not fully understood. There are evidences suggesting that the hormones confer protection against cerebral ischemia. Our aim in this study was to investigate the effects of physiological variations of estradiol plasmatic concentration on cerebral hemodynamics. We investigated cerebrovascular reactivity to hypercapnia with transcranial Doppler ultrasonography and the breath-holding index method in the right middle cerebral artery of 20 young women during the menstrual and the ovulatory phase. Data were compared with those of 20 men matched for age. The mean value of the breath-holding index was significantly higher (p<0.001) in females during the ovulatory phase than in the menstrual phase. In men, values were similar to those of women during the menstrual phase. These results suggest that estrogens influence the adaptation capacity of the cerebrovascular system. The possible pathophysiological implications of the relationships between sex hormones and cerebral hemodynamics deserve further investigation.

Adult↗
PubMed2001

Cerebrovascular reactivity and subcortical infarctions.

OBJECTIVES: To investigate the association between different kinds of ischemic lesions and cerebrovascular reactivity (CR) and to evaluate their relationships with the major risk factors for stroke. SUBJECTS AND METHODS: We evaluated CR using the breath-holding index technique during bilateral transcranial Doppler monitoring of flow velocity in the middle cerebral arteries of 41 consecutive patients attending our clinic for a recent, first-ever, ischemic stroke and in 15 control subjects. Based on the location of the lesion determined by computed tomography, the following 3 types of infarctions were identified: cortical (or territorial), single subcortical, and subcortical with multiple silent subcortical infarctions. Patients with a condition of severe carotid artery stenosis or occlusion, which in itself could account for altered CR, were excluded from this study. All physiological and pathologic conditions that could possibly cause an impairment in CR were recorded. RESULTS: The breath-holding index was significantly lower in the multiple subcortical infarctions group than in the control subjects (P < .001), single subcortical infarctions group (P < .01), and cortical infarctions group (P < .01). In all of the groups male sex (P < .05) and a history of hypertension (P < .05), regardless of whether hypertension was treated, correlated with low CR. The multiple regression analysis indicated that the only significant factor able to influence the breath-holding index was the type of lesion. CONCLUSIONS: Nonstenotic patients with first-ever stroke who had a recent symptomatic subcortical infarction associated with multiple silent infarctions seem to have an impaired cerebrovascular reserve capacity. The strong association of subcortical infarctions with multiple silent infarctions with low CR indicates the role of small vessel vasculopathy and hypoperfusion as possible pathogenetic mechanisms of subcortical infarctions with multiple silent infarctions.

Adult↗
PubMed2001

Cerebral hemodynamics in patients with carotid artery occlusion and contralateral moderate or severe internal carotid artery stenosis.

OBJECT: The purpose of this study was to evaluate cerebral hemodynamics in patients suffering from occlusion of the carotid artery (CA) and contralateral CA stenosis. METHODS: Using transcranial Doppler ultrasonography, the cerebrovascular reactivity to hypercapnia in the middle cerebral arteries was evaluated by calculating the breath-holding index (BHI) of 69 symptomatic patients suffering from internal CA (ICA) occlusion and moderate or severe contralateral ICA stenosis. To evaluate which variables influenced BHIs ipsilateral to the site of ICA occlusion, a multiple stepwise linear regression analysis was performed that included the following factors: patient age, percentage of contralateral ICA stenosis, contralateral BHI, number of collateral pathways, and presence of hypertension, diabetes, smoking, and hyperlipidemia. An analysis of variance was conducted to evaluate the impact of the type of collateral vessels on the BHI. A regression analysis showed that the BHI ipsilateral to the site of ICA occlusion could be accounted for by the contralateral BHI (which was entered at the first step of the analysis, p < 0.001) and by the number of collateral pathways (which was entered at the second step, p = 0.033). Neither the degree of contralateral ICA stenosis nor the other variables could be added to improve the model. The analysis demonstrated that the absence of collateral pathways and the presence of the anterior communicating artery (ACoA) alone were associated with lower BHI values than those found in the presence of two or three collateral vessels, regardless of the presence of an anterior collateral pathway. CONCLUSIONS: On the basis of these data one can infer that the cerebral hemodynamic status of patients with occlusive disease of the CA is influenced by individual anatomical and functional characteristics. Because improvement in contralateral hemodynamics after surgical correction of an ICA stenosis can only be expected in the presence of an ACoA, the planning of strategies for influencing cerebral blood flow distal to an ICA occlusion and, in particular, the consideration of a contralateral carotid endarterectomy, should be preceded by a careful evaluation of the intracranial hemodynamic adaptive status of the patient. Particular attention should be paid to cerebrovascular reactivity and the number and type of collateral vessels that are present.

Aged↗
PubMed2000

Effect of antiepileptic drugs on sleep.

The interactions between sleep and epilepsy are well known. A nodal point of the relationship between sleep and epilepsy is represented by pharmacological treatment. Sleep disturbances such as drowsiness are among the most frequent side effects of treatment with antiepileptic drugs, since they can deeply modify both sleep architecture and the sleep-wake cycle. Severe daytime somnolence affects patients' activities and it may facilitate the occurrence of seizures. These considerations underline the importance of antiepileptic drugs having anticonvulsant properties that do not negatively influence sleep and daytime somnolence. In this paper we review some relevant aspects of the effects of antiepileptic drugs on sleep.

Anticonvulsants↗
PubMed2000

Effects of lamotrigine on nocturnal sleep, daytime somnolence and cognitive functions in focal epilepsy.

OBJECTIVES: The aim of our study was to evaluate possible changes in nocturnal sleep, daytime somnolence and cognitive functions induced by add-on therapy with lamotrigine (LTG). MATERIAL AND METHODS: Thirteen patients affected by seizures resistant to common antiepileptic drugs (AEDs) underwent nocturnal polysomnographic monitorings, daytime somnolence evaluations and a neuropsychological battery before and after 3 months of treatment with LTG. RESULTS: With LTG therapy we observed a significant increase in REM sleep and a significant reduction in the number of entries into REM and stage shifts. No significant correlation was observed between the decrease in nocturnal epileptiform activity and the increase in REM sleep. Other sleep parameters were unmodified. No significant changes were observed in daytime somnolence and in cognitive performances. CONCLUSION: LTG may produce positive effects on epileptic seizures and interictal abnormalities without interfering negatively on REM sleep, with improvement of sleep stability and without changes in daytime somnolence and neuropsychological performances. For these reasons it could be an important drug for improving epileptic patients' quality of life.

Adolescent↗
PubMed2000

Effect of anticonvulsants on nocturnal sleep in epilepsy.

Our objective was to determine, in three separate studies, the effects of controlled-release carbamazepine (CBZ-CR), lamotrigine (LTG), and gabapentin (GBP) on nocturnal sleep in epilepsy. Antiepileptic drugs (AEDs) control seizures and also modify hypnic structure. Despite widespread clinical use, their effects on sleep are not well known. PSG was performed in all three studies as follows: CBZ-CR: at baseline, after initial administration of CBZ-CR 400 mg, and after 1 month of CBZ-CR treatment (400 mg BID) in a sample of seven temporal lobe epileptic (TLE) patients. Results were compared with those of nine healthy volunteers; LTG: at baseline, after 3 months of stable treatment with LTG (300 mg/day); GBP: at baseline, after 3 months of stable treatment with GBP (1800 mg/day). Significant findings are as follows for each study. The acute administration of CBZ-CR increased number of stage shifts, reduced REM sleep, and increased REM sleep fragmentation. In the TLE group, these effects were almost completely reversed after chronic treatment. LTG increased REM sleep, reduced number of entries into REM sleep, decreased number of phase shifts, and decreased percentage of slow-wave sleep. GBP increased REM sleep percentage, increased mean duration of REM periods, reduced number of awakenings, and reduced stage 1 sleep percentage. We conclude that CBZ-CR disrupts REM sleep, but only during acute administration. LTG and GBP improve sleep stability while reducing seizures.

Acetates↗
PubMed1999

Association of trisomy 9p and band heterotopia.

Patients with the trisomy 9p syndrome and CNS abnormalities have been poorly assessed. We report a patient with trisomy 9p who showed band heterotopia on MRI. Abnormal neuronal migration is sufficiently frequent in patients with the trisomy 9p syndrome that brain MRI should be routinely considered in all patients with this syndrome.

Adult↗
PubMed1999

Sleep abnormalities in mentally retarded autistic subjects: Down's syndrome with mental retardation and normal subjects.

We compared sleep parameters in mentally retarded infantile autism (MRIA) and mentally retarded Down's syndrome (MRDS) by means of polysomnography, evaluating traditional analysis with particular attention to the phasic components in each disorder. Data were compared with those obtained in normal subjects matched for age and sex. Mental age, Intellectual Quotient and the Childhood Autism Rating Scale were performed to obtain an estimation of the neuropsychological deficit. Abnormalities of phasic components of sleep and the presence of REM sleep components into non-REM sleep were observed in both MRIA and MRDS even if in different ways. In fact, MRDS subjects presented a reduction of REM sleep percentage and R index (number of high frequency REMs against number of low frequency REMs) and this was positively correlated to a low IQ. Unlike MRDS subjects, MRIA subjects did not show any parallelism between intellectual abilities and REM sleep deficit. In addition, the presence of undifferentiated sleep in autistic subjects implies a maturational deficit that is still present in adulthood. Finally, a high R index in MRIA was observed. This finding, which is not present in MRDS, could represent an estimation of the disorganized arrival of information caused by a dyscontrol or a reduction of inhibitor pathway. With reference to sleep mechanisms, our results suggest that the cognitive deficit in MRIA may differ from that of MRDS subjects. A maturational deficit of CNS with a dysfunction of brainstem monoaminergic neurons could represent the underlying mechanism.

Adolescent↗
PubMed1999

Does the antimigraine action of flunarizine involve the dopaminergic system? A clinical-neuroendocrinological study.

We have investigated the prolactin response to bromocriptine (BRC), a D2 dopamine receptor agonist in migrainous women before and after treatment with flunarizine. We evaluated whether this test was predictive of therapeutic efficacy of flunarizine treatment and whether the therapeutic response to flunarizine treatment was related to its effect on dopaminergic system at tuberoinfundibular level. Ten migrainous women underwent a BRC test in the late follicular phase before and after 1 and 3 months of treatment with flunarizine 10 mg at bedtime. Blood samples of prolactin (PRL), growth hormone, follicle-stimulating hormone, luteinizing hormone, estradiol and progesterone were taken at basal condition. PRL was also evaluated 1 and 2 h after BRC (2.5 mg) administration. Each patient kept a daily headache diary for 1 month prior to the test and throughout the study. The level of PRL inhibition after BRC administration, observed before flunarizine treatment, was not predictive of the therapeutic response observed after 1 and 3 months of treatment. The effect of flunarizine on PRL level was not related to the therapeutic efficacy of the drug. These data suggest that flunarizine does not attenuate the activity of dopaminergic neurons in migrainous patients, and that the antimigraine effect of flunarizine does not seem related to its action on dopaminergic system at least at tuberoinfundibular level.

Adult↗
PubMed1998

Impairment of daytime cerebrovascular reactivity in patients with obstructive sleep apnoea syndrome.

Several studies have demonstrated a clear association between snoring, sleep apnoea and increased risk of stroke. However, the possible role of sleep apnoea in the pathophysiogenetic mechanisms of cerebrovascular disease is still unknown. Our aim in this study was to investigate cerebral haemodynamic changes during the waking state in eight patients with sleep apnoea syndrome (OSAS) by means of transcranial Doppler (TCD). In particular, we studied cerebral vascular reactivity (CVR) to hypercapnia calculated by means of the breath holding index (BHI). The investigation was performed in the early morning, soon after awakening, and in the late afternoon. Data were compared with those of eight healthy subjects matched for age and vascular risk factors. OSAS patients showed significantly lower BHI values with respect to controls both in the morning (0.56 vs. 1.36; P < 0.0001) and in the afternoon (1.12 vs. 1.53; P < 0.0001). In patients, BHI values in the afternoon were significantly higher than in the morning (P < 0.0001). These data demonstrate a diminished vasodilator reserve in OSAS patients, particularly evident in the morning. This reduction of the possibility of cerebral vessels to adapt functionally in response to stimulation could be linked to hyposensitivity of cerebrovascular chemoreceptors after the continuous stress caused by nocturnal hypercapnia.

Adult↗
PubMed1998

Bilateral hemispheric activation in the early recovery of motor function after stroke.

BACKGROUND AND PURPOSE: Functional recovery after cerebral infarction is a complex phenomenon that depends on various factors. The aim of this study was to investigate changes in cerebral perfusion during motor activity in stroke patients with very early recovery of motor function. METHODS: We included 9 consecutive patients hospitalized for acute-onset hemiparesis who showed complete functional recovery within 24 hours. CT of the brain showed an ischemic or hemorrhagic cerebral lesion in areas compatible with the symptomatology. Within 36 hours (range, 28 to 36) all patients were examined for the effects of a thumb-to-finger opposition task on cerebral blood flow in the middle cerebral arteries, evaluated by means of bilateral transcranial Doppler ultrasonography. Data were compared with those of 9 healthy subjects matched for age and sex. In patients, the evaluation was repeated 2 to 4 months later. RESULTS: A comparable increase in flow velocity (% mean+/-SD) was observed with respect to baseline in the contralateral middle cerebral artery during motor activity with patients' normal (8.8+/-2.0%) and recovered hand (9.7+/-4.1%) and with both hands of control subjects (10.6+/-1.4%). In the middle cerebral artery ipsilateral to the hand performing the motor task, the increase in flow velocity was significantly higher (P<0.0001) during movement of the recovered hand in patients (8.6+/-2.7%) than during movement of the normal hand in both patients (2.6+/-1.6%) and control subjects (1.4+/-0.7%). In patients, pattern of changes in flow velocity during motor performance remained the same in the second evaluation. CONCLUSIONS: These observations suggest that areas of the healthy hemisphere can be activated soon after a focal injury and contribute to the positive evolution of a functional deficit in some patients. This phenomenon of ipsilateral activation cannot be considered transient because it is evident months after stroke onset.

Aged↗
PubMed1998

Cerebral hemodynamic changes in sleep apnea syndrome and effect of continuous positive airway pressure treatment.

BACKGROUND AND OBJECTIVE: A clear association among snoring, sleep apnea, and increased risk of stroke has been shown by previous studies. However, the possible role played by sleep apnea in the pathogenesis of cerebrovascular disease is subject to debate. To evaluate the influence of hemodynamic changes caused by obstructive sleep apnea syndrome (OSAS), we investigated cerebrovascular reactivity to hypercapnia in patients with OSAS. METHODS: The study was performed at baseline and after 1 night and 1 month of nasal continuous positive airway pressure (n-CPAP) therapy, with patients in the waking state (8:00 to 8:30 AM and 5:30 to 6:00 PM) with transcranial Doppler ultrasonography. Cerebrovascular reactivity was calculated with the breath-holding index (BHI). RESULTS: In the baseline condition, compared with normal subjects, patients with OSAS showed significantly lower BHI values in both the morning (0.57 versus 1.40, p < 0.0001) and the afternoon (1.0 versus 1.51, p < 0.0001). Cerebrovascular reactivity was significantly higher in the afternoon than it was in the morning in both patients (p < 0.0001) and controls (p < 0.05). In patients, the BHI returned to normal values, comparable with those of control subjects, after both 1 night and 1 month of n-CPAP therapy. CONCLUSIONS: These findings suggest an association between OSAS and diminished cerebral vasodilator reserve. This condition may be related to the increased susceptibility to cerebral ischemia in patients with OSAS, particularly evident in the early morning.

Adult↗
PubMed1997

Nocturnal sleep and daytime somnolence in untreated patients with temporal lobe epilepsy: changes after treatment with controlled-release carbamazepine.

PURPOSE: To define sleep disturbances in patients with temporal lobe epilepsy (TLE) and explore the association between carbamazepine (CBZ) therapy, sleep, and daytime somnolence. METHODS: We recorded nocturnal polysomnography and measured subjective and objective daytime somnolence in a group of newly diagnosed TLE patients, who had no evidence of anatomic brain lesion on neuroimaging and had never been treated before. Recordings were performed at baseline, after the initial administration of 400 mg CBZ-controlled release (CR) and after 1 month of treatment (400 mg twice daily b.i.d.). The findings were compared with those of a group of young healthy volunteers, both at baseline and after the first administration of CBZ. The chronic effect of CBZ-CR treatment was evaluated only in TLE patients. RESULTS: At baseline, nocturnal sleep patterns of TLE patients did not show marked alterations when the influence of seizures, cerebral lesions, and drugs had been ruled out. In both the TLE and the control groups, initiation of CBZ therapy provoked a reduction and a fragmentation of rapid eye movement (REM) sleep and an increase in the number of sleep stage shifts. In the TLE group, these effects were almost completely reversed after 1 month of treatment, and no significant difference was noted between baseline condition and long-term follow-up. With regard to daytime sleepiness, initial administration of the drug caused an increase in objective sleepiness only in the control group. Subjective sleepiness was higher in the control group than in the TLE group but was not modified by the drug. CONCLUSIONS: We conclude that CBZ-CR has negative effects on REM sleep during initial administration but chronic treatment does not significantly modify nocturnal sleep or daytime somnolence.

Adult↗