Search PubMed⌕ Search

Biomedical subjects

G Comi

Publications and source records attributed to G Comi.

At least 37 records · Page 2Linked to original sources
PubMed2005

Electroencephalographic background desynchronization during cerebral blood flow reduction.

OBJECTIVE: The aim of this study is to evaluate the usefulness of a spectral function detecting cerebral hypoperfusion. METHODS: Continuous electroencephalographic monitoring was employed during 47 consecutive carotid endarterectomies. Patients were assigned to 3 different groups according to the entity of electroencephalographic changes during carotid clamping (major changes: group A; moderate changes: group B; no change: group C). The desynchronization function, indicating the reduction of the 8-15 Hz band power, and the desynchronization index were calculated. RESULTS: Group A function decreased within 20s from clamping, with a constant slope (7.14). Desynchronization indexes were: 76.85% (group A), 40.23% (group B) and 15.29% (group C). Difference among groups was statistically significant (P < 0.0001). A case of syncope due to asystole is also reported, showing the same pattern in the descending phase of the function. CONCLUSIONS: The stereotyped time course of the desynchronization function describes the cerebral reaction to significant blood flow reduction. Values of desynchronization index exceeding 65% seem to correctly detect patients with cerebral hypoxic risk. SIGNIFICANCE: The analysis of the 8-15 Hz band desynchronization is helpful in the evaluation of cerebral hypoperfusion during carotid endarterectomy. This method could be employed in monitoring different clinical situations of ischemia.

Aged↗
PubMed2005

A whole brain MR spectroscopy study from patients with Alzheimer's disease and mild cognitive impairment.

Brain damage in Alzheimer's disease (AD) and mild cognitive impairment (MCI) is widespread with involvement of large portions of the neocortex and the subcortical white matter. A quantitative measure of neuronal damage of the entire brain might be valuable in the context of large-scale, longitudinal studies of these patients. This study investigated the extent of neuroaxonal injury of patients with AD and MCI using a novel unlocalized proton magnetic resonance spectroscopy ((1)H-MRS) technique, which allows quantification of the concentration of N-acetylaspartate from the whole of the brain tissue (WBNAA). Conventional brain MRI and WBNAA were obtained from 28 AD patients, 27 MCI patients and 25 age-matched controls. Normalized brain volume (NBV) was also measured using an automated segmentation technique. WBNAA and NBV showed a significant heterogeneity between groups (P < 0.001). WBNAA concentration was different between controls and MCI patients (P = 0.003), but not between MCI and AD patients (P = 0.33). NBV differed both between controls and MCI patients (P = 0.02) and between MCI and AD patients (P = 0.03). A multivariate regression model retained WBNAA as the best MRI predictor of the Mini Mental State Examination score (P = 0.001). Significant neuronal damage, which is related to the extent of cognitive decline, can be quantified in the whole brain tissue of patients with AD, using a novel (1)H-MRS approach. The demonstration in patients with MCI of MR structural and metabolic findings, intermediate between those of healthy volunteers and those of AD patients, indicates that neuronal damage is already evident and widespread in individuals with MCI before they are clinically demented.

Aged↗
PubMed2005

Movement preparation is affected by tissue damage in multiple sclerosis: evidence from EEG event-related desynchronization.

OBJECTIVE: To investigate the impact of brain tissue damage in Multiple Sclerosis (MS) on the efficiency of programming of voluntary movement, assessed using event-related desynchronization of the EEG. METHODS: The onset latency of mu ERD (percent desyncronization of the mu rhythm preceding movement onset) to hand movement was studied in 34 MS patients. ERD onset was compared with normative data and correlated with T1 and T2 total lesion volume (TLV) at magnetic resonance imaging (MRI). RESULTS: ERD onset latency was significantly correlated with T1-TLV (r = 0.53, P = 0.001) and T2 lesion load (r = 0.5, P = 0.003), even after correcting for disability. Patients with higher T1-TLV had significantly delayed ERD onset compared with normal subjects and with patients with lower T1-TLV; patients with higher T2-TLV had significantly delayed ERD compared with normal subjects only. ERD onset latency was not correlated to clinical disability. CONCLUSIONS: Our finding of delayed ERD onset in patients with more severe measures of brain damage, independently from clinical disability, suggests that functional cortico-cortical and cortico-subcortical connections underlying the expression of ERD during programming of voluntary movement are disrupted by the MS related pathological process. Further, studies are needed to evaluate the role of specific anatomical cortico-subcortical circuits in determining this abnormality. SIGNIFICANCE: The extent of brain lesion load in multiple sclerosis affects cortical changes related to motor preparation, detected by analysis of onset latency of event-related desynchronization (ERD) of the mu rhythm to self-paced movement.

Adult↗
PubMed2005

Quantification of cervical cord pathology in primary progressive MS using diffusion tensor MRI.

OBJECTIVE: To investigate the extent and severity of cervical cord damage using diffusion tensor MRI (DT-MRI) and histogram analysis in patients with primary progressive MS (PPMS). METHODS: Diffusion-weighted sensitivity-encoded (SENSE) echoplanar images of the cervical cord and brain dual-echo and diffusion-weighted scans were acquired from 24 patients with PPMS and 13 healthy controls. Cord and brain mean diffusivity and fractional anisotropy histograms were produced. An analysis of variance model, adjusting for cord volume, was used to compare cord DT-MRI parameters from controls and patients. RESULTS: Compared to healthy controls, PPMS patients had reduced cervical cord cross-sectional area and average cord fractional anisotropy (p = 0.007), and increased cord mean diffusivity (p = 0.024). No correlations were found between DT-MRI metrics of the cord and quantities obtained from conventional and DT-MRI of the brain. CONCLUSIONS: DT-MRI of the cervical cord can quantify the extent of diffuse cord pathology in patients with PPMS. Such cord diffusivity changes in patients with PPMS are likely to reflect irreversible axonal injury and reactive gliosis and seem to be independent of brain damage.

Adult↗
PubMed2005

Induction versus escalation therapy.

Most of the consensus groups in Europe and America support an early decision-making therapeutic approach in patients with a diagnosis of multiple sclerosis (MS), either with interferon-beta or glatiramer acetate, which have been demonstrated to be a reasonable therapeutic strategy because of their benefit. The "treat-early approach" within disease management is based on the assumption, particularly during the early phase of the disease, of the reduction of both relapse rate and of the ongoing inflammatory processes may delay irreversible neurological damages. As soon as the MS diagnosis is certain or even in patients with a first episode suggestive of MS, with negative prognostic factors and a typical presentation, "induction therapy", which is more aggressive on the immune system, seems to have more relevant short- and long-lasting beneficial effects. However, if the disease course is suboptimally controlled, an "escalating strategy", using mitoxantrone, cyclophosphamide, various other immunoactive agents or a combination of different drugs, is suggested. The current challenge in therapeutic strategy is to identify the most effective drug, or combination of drugs, during a specific phase of the disease for each single patient. Anyhow, the decision to adopt a combination therapy in patients with a low response to monotherapy should not be delayed until severe irreversible disability is evident.

Adjuvants, Immunologic↗
PubMed2005

Dominant LMNA mutations can cause combined muscular dystrophy and peripheral neuropathy.

The coexistence of neurogenic and myogenic features in scapuloperoneal syndrome is rarely ascribed to a single gene. Defects in the nuclear envelope protein lamin A/C, encoded by the LMNA gene, have been shown to be associated with a variety of disorders affecting mainly the muscular and adipose tissues and, more recently, with autosomal recessive Charcot-Marie-Tooth type 2 neuropathy. This report is about a patient presenting features of myopathy and neuropathy due to a dominant LMNA mutation, suggesting that the peripheral nerve might be affected in primary LMNA myopathy. Our observations further support the marked intrafamilial and interfamilial phenotypic heterogeneity associated with lamin A/C defects.

Adolescent↗
PubMed2005

Imaging spinal cord damage in multiple sclerosis.

During the past 2 decades, the considerable improvement of magnetic resonance (MR) technology and the development of new MR strategies capable of providing an in vivo overall assessment of multiple sclerosis (MS) pathology have allowed us to obtain important novel pieces of information on disease evolution in the brain. However, despite this, the correlation between brain MR imaging metrics and clinical disability are still suboptimal. A reason for this discrepancy might be the involvement of clinically eloquent structures, such as the spinal cord, which owing to technical challenges have not been extensively studied using MR imaging until very recently. An objective and accurate estimate of the presence and extent of spinal cord damage might indeed contribute to increasing the strength of the correlations between clinical and MRI metrics. This review summarizes the main results obtained from the application of conventional and modern MR-based techniques for the evaluation of spinal cord damage in MS.

Diffusion Magnetic Resonance Imaging↗
PubMed2005

Randomized study of once-weekly interferon beta-1la therapy in relapsing multiple sclerosis: three-year data from the OWIMS study.

BACKGROUND: Once weekly interferon beta-1a for multiple sclerosis (OWIMS) demonstrated modest, but significant, magnetic resonance imaging (MRI) benefit of once-weekly (qw) interferon (IFN) beta-1a at 48 weeks, but no significant effect on relapses. OBJECTIVE: An OWIMS extension permitted assessment of longer-term efficacy/safety of qw IFN beta-1a in relapsing-remitting multiple sclerosis (RRMS). METHODS: Placebo patients were rerandomized to IFN beta-1a, 22 or 44 mcg qw, for two additional 48-week intervals. Primary outcome was MRI lesion activity. Relapse rate and other MRI measures were secondary outcomes. RESULTS: After three years, median (mean) T2 lesion count/patient/scan was 1.3 (2.6) for 44 mcg, 1.7 (3.3) for 22 mcg, 1.7 (3.4) for placebo/22 mcg, 2.0 (3.6) for placebo/44 mcg (all differences not significant). Annualized relapse rates were lowest for 44 mcg (0.77) versus other groups (0.83-0.86, not significant). Persistent neutralizing antibodies did not affect relapse rates, but MRI active lesions were increased in antibody-positive patients receiving 44 mcg compared to antibody negative patients. CONCLUSIONS: In RRMS, once weekly IFN beta-1a, particularly 44 mcg, can induce a significant MRI, but not relapse, effect, compared with placebo. No significant dose effect was seen. In contrast to the significant effect observed with three-times-weekly dosing of subcutaneous IFN beta-1a compared with placebo, this study confirms the lack of meaningful clinical benefit with once-weekly dosing.

Adjuvants, Immunologic↗
PubMed2005

The distribution of the magnetic resonance imaging response to glatiramer acetate in multiple sclerosis.

We investigated the distribution of the magnetic resonance imaging (MRI)-measured response to glatiramer acetate (GA) treatment in multiple sclerosis (MS) using data from a clinical trial of relapsing-remitting (RR) MS. A fixed and a random effects model were used to quantify the between-patient heterogeneity in treatment response, expressed as new enhancing lesion percentage reduction. In 95% of the patients, lesion reduction due to treatment was estimated to range between -20% and -54%, indicating a rather homogeneous effect of GA on MRI-measured disease activity in RRMS.

Brain↗
PubMed2005

Disease-modifying drugs in childhood-juvenile multiple sclerosis: results of an Italian co-operative study.

OBJECTIVE: Immunomodulatory drugs (IDs) (interferon beta (IFNgamma) and glatiramer acetate (GA)) reduce relapse rate and disease progression in relapsing remitting multiple sclerosis (RRMS) but extensive data are not available on the effectiveness and tolerability of these drugs in childhood or adolescence. The aim of this study was to evaluate the impact of IFNbeta and GA in MS patients treated before 16 years of age. METHODS: A research group (Immunomodulatory Treatment of Early onset MS (ITEMS)) was promoted in Italy to collect a large series of patients affected by clinically definite and RRMS and treated with IDs before 16 years of age. Fifteen centres recognized subjects suitable for inclusion: 76 patients (52 females) were collected with a mean age at onset of 12.4 (SD 2.5) years, a mean disease duration of 18.6 (SD 14.7) and a relapse rate of 3.1 (SD 2.9). RESULTS: Results were evaluated in 65 (45 females) subjects with a pretreatment and a treatment duration >3 months: 38 were treated with IFNbeta-1a once weekly (Avonex), 18 with IFNbeta three times weekly (16 with Rebif, 2 with Betaferon) and nine with GA (Copaxone). The mean pretreatment period was respectively 20, 18 and 9.2 months. The treatment duration lasted respectively 23.3, 40.7 and 33.3 months. The mean annualized relapse rate decreased dramatically during the treatment: from 2.4 to 0.4 in the Avonex group, from 3.2 to 0.8 in the Rebif-Betaferon group and from 2.8 to 0.25 in the GA group. The mean final EDSS scores were respectively (in brackets the initial scores): 1.3 (1.4), 1.6 (1.8) and 0.6 (1.1). In the whole group, the final score was unchanged or reduced in all subjects except eight. Clinical side effects were recorded in 41/65 subjects (mainly in subjects treated with IFNbeta), abnormal laboratory findings were observed in 13/65 subjects: they were transient in most cases. IFNgamma was stopped in six cases: in four because of inefficacy and in two cases because of side effects. CONCLUSIONS: Sixty-five clinically definite MS subjects were treated during childhood or adolescence with IDs. The treatment reduced the relapse rate and the progression of the disease in most cases. Side effects were common in subjects treated with IFNbeta but were well tolerated in most cases.

Adjuvants, Immunologic↗
PubMed2005

Imaging the optic nerve in multiple sclerosis.

Although multiple sclerosis (MS) frequently involves the optic nerves, imaging this structure is not yet performed routinely in clinical practice. The recent improvement of magnetic resonance (MR) technology and the development of new MR strategies, capable of providing an, in vivo, overall assessment of MS pathology has allowed objective metrics to be obtained for monitoring disease evolution, essentially in the brain. However, despite this progress, the correlation between brain MR metrics of the disease and clinical disability are still disappointing. An objective and accurate estimate of the presence and extent of optic nerve involvement might help to overcome this clinical/MRI paradox. This review summarizes the main results obtained from the application of conventional and modern MR-based techniques for the evaluation of optic nerve damage in MS.

Atrophy↗
PubMed2004

An MT MRI study of the cervical cord in clinically isolated syndromes suggestive of MS.

Cervical cord magnetization transfer ratio (MTR) histograms were obtained from 45 patients at presentation with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS). The mean values of MTR histogram-derived metrics were not different between CIS patients and healthy control subjects or between patients with and without evidence of disease dissemination in time. Only three patients showed significantly lower cord MTR values than control subjects. These findings suggest the absence of intrinsic structural damage of the cervical cord soon after the onset of CIS suggestive of MS, even in those patients with an early evolution to MS.

Adolescent↗
PubMed2004

Similar low frequency of anti-MOG IgG and IgM in MS patients and healthy subjects.

The authors used a liquid-phase radiobinding assay to measure serum anti-myelin oligodendrocyte protein (MOG) immunoglobulin (Ig) G in 87 patients with multiple sclerosis (MS), in 12 patients with encephalomyelitis, and in 47 healthy subjects. Anti-MOG IgM was determined in samples obtained at onset from 40 of 87 patients with MS and in control subjects. The frequency of positive samples with low titers of anti-MOG IgG (< or =5.7%) and IgM (< or =8.3%) was similar in all the groups and subgroups. Binding competition experiments showed that these antibodies had low affinity. Anti-MOG antibodies are not disease specific.

Adolescent↗
PubMed2004

Measurement error of two different techniques for brain atrophy assessment in multiple sclerosis.

The measurement errors associated with two techniques for brain atrophy assessment in multiple sclerosis (MS) were estimated. The measurement error of a semiautomated, nonnormalized technique with partial brain coverage was about twofold higher than that of a fully automated, normalized technique with full brain coverage (Structural Image Evaluation of Normalized Atrophy software [SIENA]). As shown by the analysis of data from a clinical trial of glatiramer acetate, the use of SIENA increases the study power to detect a treatment effect on brain volume changes in MS patients.

Atrophy↗
PubMed2004

Late-onset cerebellar ataxia with hypogonadism and muscle coenzyme Q10 deficiency.

Two brothers had late-onset progressive ataxia, cerebellar atrophy, and hypergonadotropic hypogonadism associated with coenzyme Q10 (CoQ10) deficiency in skeletal muscle. Both patients improved on high-dose CoQ10 supplementation, stressing the importance of CoQ10 deficiency in the differential diagnosis of cerebellar ataxia, even when onset is late.

Adult↗
PubMed2004

Magnetization transfer and diffusion tensor MRI show gray matter damage in neuromyelitis optica.

Using magnetization transfer (MT) and diffusion tensor (DT) MRI, the authors assessed the extent of tissue damage of the brain normal-appearing white and gray matter (NAGM) in patients with neuromyelitis optica (NMO). Compared to healthy controls, patients with NMO showed reduced MT ratio and increased mean diffusivity of the NAGM. This challenges the classic notion of a sparing of the brain tissue in the course of NMO.

Adult↗