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Biomedical subjects

R Ferri

Publications and source records attributed to R Ferri.

At least 19 recordsLinked to original sources
PubMed2003

Reversion of transformed phenotype in ovarian cancer cells by intracellular expression of anti folate receptor antibodies.

The alpha-folate receptor (FR) is selectively overexpressed in 90% of nonmucinous ovarian carcinomas, whereas no expression is detectable in normal ovarian surface epithelium (OSE). Indirect evidence suggests that FR expression is associated with tumor progression and affects cell proliferation. To evaluate better the role of FR, we developed an approach based on intracellular expression of single-chain (sc) antibodies (intrabody) to downmodulate membrane expression of FR in ovary cancer cells. IGROV-1 and SKOV3 ovarian carcinoma cell lines were transfected with an anti-FR intrabody. Transfectants and parental cells were tested for FR, integrins and anti-FR intrabody expression by fluorescence-activated cell sorting (FACS), reverse transcription and polymerase chain reaction (RT-PCR) and/or immunoblotting. Cell growth characteristics and adhesion properties were evaluated in liquid, semisolid and organotypic cultures. The anti-FR scFv inhibited FR expression from 60 to 99%. At physiological concentrations of folate, proliferation varied directly as a function of FR expression. FR downmodulation was accompanied by reduced colony-forming ability in soft agar, morphological change of the cells, significant enhanced adhesion to laminin or Matrigel, a two- to three-fold increase in alpha6beta4 integrin expression, and a marked reduction in laminin production. In three-dimensional organotypic cultures, anti-FR intrabody-transfected IGROV1 cells grew as a single-ordered layer, reminiscent of normal OSE growth in vivo. In conclusion, the anti-FR intrabody reverses the transformed phenotype in ovary cancer cells and may provide an efficient means to inhibit selectively the growth of these cells.

Antibodies, Monoclonal↗
PubMed2002

Transcranial magnetic stimulation after pure motor stroke.

OBJECTIVES: The objective of this study was to assess the sensitivity of motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) in demonstrating the possible subclinical impairment of the corticospinal pathway after recovery, in patients with a clinical history of pure motor stroke (PMS) due to a single lacunar infarct detectable by magnetic resonance imaging (MRI). METHODS: MEPs were recorded from the first dorsal interosseous muscle of 20 healthy subjects and 40 patients, 6 months or more after PMS onset. Patients were evaluated clinically by means of the NIH stroke scale, the Medical Research Council (MRC) scale and the Barthel Index. The patients with full hand strength recovery and the normal controls were also tested by means of the 9-hole peg test. RESULTS: Motor threshold (MT), MEP amplitude and central motor conduction time (CMCT) of the affected side were significantly different from those of the normal side and of the control subjects. MT, MEP amplitude and CMCT obtained after stimulation of the affected hemisphere were significantly correlated with the MRC scale values of the affected hand. Eighty-six percent of patients with persistent hand strength deficit showed MEP abnormalities. In 21 patients with complete clinical recovery, a significant increase in MT and decrease in MEP amplitude on the affected side were observed. CONCLUSIONS: After PMS, neurophysiological changes may persist despite complete clinical recovery. TMS represents a sensitive tool that enables to demonstrate objectively the clinical and subclinical impairment of the corticospinal pathway.

Adult↗
PubMed2001

Transcranial magnetic stimulation in Alzheimer disease: motor cortex excitability and cognitive severity.

To study the possible changes of cortical excitability in the Alzheimer disease (AD) by transcranial magnetic stimulation (TMS) and to evaluate their eventual correlation with its stage twenty-one AD patients and 18 normal controls underwent TMS. Motor threshold, amplitudes of motor evoked potentials (MEPs), central motor conduction time (CMCT) and silent period (SP) were considered. The motor threshold in AD patients was lower than in normal subjects with a significant correlation between the stage of cognitive severity. The amplitude of MEPs was increased and the SP duration was reduced in AD patients. No significant differences were obtained for CMCT. These findings could suggest a correlation between increased motor cortical excitability and cognitive severity. Moreover, the increased cortical excitability could represent a key to understand the mechanism of AD and may have implication for novel treatment strategies.

Aged↗
PubMed2001

Regional cerebral hyperperfusion and nitric oxide pathway dysregulation in Fabry disease: reversal by enzyme replacement therapy.

BACKGROUND: Fabry disease is an X-linked lysosomal deficiency of alpha-galactosidase A that results in cellular accumulation of galacto-conjugates such as globotriosylceramide, particularly in blood vessels. It is associated with early-onset stroke and kidney and heart failure. METHODS AND RESULTS: Using [(15)O] H(2)O and PET, we found increased resting regional cerebral blood flow in Fabry disease without evidence of occlusive vasculopathy or cerebral hypoperfusion. Because nitric oxide is known to play an important role in vascular tone and reactivity, we studied plasma nitrate, nitrite, and low-molecular-weight S-nitrosothiol levels by chemiluminescence. Skin biopsy specimens and archived brain tissue were also examined immunohistochemically for nitrotyrosine. Plasma nitrate, nitrite, and low-molecular-weight S-nitrosothiol were in the normal range; however, enhanced nitrotyrosine staining was observed in dermal and cerebral blood vessels. After a double-blind, placebo-controlled trial of alpha-galactosidase A therapy, the resting regional cerebral blood flow in the treated group was significantly reduced, with a notable decrease of nitrotyrosine staining in dermal blood vessels. CONCLUSIONS: These findings suggest a chronic alteration of the nitric oxide pathway in Fabry disease, with critical protein nitration that is reversible with enzyme replacement therapy.

Adult↗
PubMed2001

Relationship between Delta, Sigma, Beta, and Gamma EEG bands at REM sleep onset and REM sleep end.

OBJECTIVE: The aim of the present study was to analyze in detail the relationship of two newly introduced measures, related to the Beta and Gamma EEG bands during REM sleep, with Delta and Sigma activity at REM sleep onset and REM sleep end, in order to understand their eventual role in the sleep modulation mechanism. METHODS: For this purpose, power spectra of 1 EEG channel (C4, referred to A1) were obtained by means of the fast Fourier transform and the power of the bands ranging 0.75-4.50 Hz (Delta), 4.75-7.75 (Theta), 8.00-12.25 (Alpha), 12.50-15.00 (Sigma), 15.25-24.75 (Beta), 25.00-34.75 (Gamma 1), and 35.00-44.75 (Gamma 2) was calculated for the whole period of analysis (7 h), in 10 healthy subjects. Additionally, two other time series were calculated: the ratio between Beta and Gamma2, and between Gamma1 and Gamma2 (Beta and Gamma ratios). For each subject, we extracted 3 epochs of 30 min corresponding to the 15 min preceding and the 15 min following the onset of the first 3 REM episodes. Data were then averaged in order to obtain group mean values and standard deviation. The same process was applied to the 30-min epochs around REM sleep end. RESULTS: The course of the Delta band around REM sleep onset was found to be characterized by a first phase of slow decline lasting from the beginning of our window up to a few seconds before REM onset; this phase was followed by a sudden, short decrease centered around REM onset, lasting for approximately 1.5-2 min. At the end of this phase, the Delta band reached its lowest values and remained stable up to the end of the time window. The Sigma band showed a similar course with stable values before and after REM sleep onset. The Beta and Gamma ratios also showed a 3-phase course; the first phase, in this case, was characterized by stable low values, from the beginning of our window up to approximately 5 min before REM onset. The following second phase was characterized by an increase which reached its maximum shortly after REM sleep onset (approximately 1 min). In the last phase, both Beta and Gamma ratios showed stable high values, up to the end of our time window. At REM sleep end, the Delta band only showed a very small gradual increase, the Sigma band presented a more evident gradual increase; on the contrary, both Beta and Gamma ratios showed a small gradual decrease. CONCLUSIONS: The results of the present study show a different time synchronization of the changes in the Delta band and in Beta and Gamma ratios, at around REM sleep onset, and seem to suggest that the oscillations of these parameters might be modulated by mechanisms more complex than a simple reciprocity. All these considerations point to the fact that REM sleep can be considered as a complex phenomenon and the analysis of high-frequency EEG bands and of our Beta and Gamma ratios represent an additional important element to include in the study of this sleep stage.

Adult↗
PubMed2001

Non-linear EEG analysis in children with epilepsy and electrical status epilepticus during slow-wave sleep (ESES).

OBJECTIVE: The objective of this work was to study the non-linear aspects of electroencephalography (EEG) in children with epilepsy and electrical status epilepticus during slow-wave sleep (ESES). METHODS: In this study, we recorded the sleep EEG in 5 subjects with ESES (4 males and one female, aged 6.5-10 years) who were also mentally retarded and affected by cerebral palsy (3 subjects) and hydrocephalus (two subjects). The signals were sampled at 128Hz and stored on hard disk. All the subsequent computational steps were performed on EEG epochs (4096 data points) selected from wakefulness and non-rapid eye movement (non-REM) (with ESES) or REM sleep. The dynamic properties of the EEG were assessed by means of the non-linear cross prediction (NLCP) test which uses 3 different 'model' time series in order to predict non-linearly the original data set (Pred, Ama and Tir). Pred is a measure of the predictability of the time series and Ama and Tir are measures of asymmetry, indicating non-linear structure. Moreover, the correlation dimension (D2) was estimated by means of the algorithm by for the epochs showing non-linear nature. RESULTS: The NLCP test provided evidence of significant non-linear dynamics in all epochs of non-REM sleep, when ESES was evident. Only during this stage, the possible presence of low-dimensional chaos could also be suspected (average D2=4.02; range 3.16-6.21). EEG without ESES could not be distinguished from linearly filtered noise. CONCLUSIONS: The results of the present study seem to indicate that subjects with ESES show a profound modification of their EEG dynamics with the occurrence, during sleep, of long periods characterized by non-linear dynamics and, probably, low-dimensional chaotic structure able to modify in a substantial way their brain functioning during sleep.

Child↗
PubMed2001

Nail pathology in patients with hemiplegia.

BACKGROUND: It is well known that nails can be involved in some diseases of the central nervous system; however, no systematic study has been carried out in order to evaluate the incidence and the possible mechanisms of these nail changes in hemiplegia. OBJECTIVES: To study the presence of nail pathology specifically associated with hemiplegia and to evaluate its incidence and its temporal relationship with the onset of the neurological deficit. METHODS: In an open study, fingernails and toenails were examined by a dermatologist; 108 were patients with hemiplegia due to a stroke, consecutively admitted to our Department of Neurology between 1995 and 1998, and 121 were normal controls. RESULTS: Onychodystrophy of fingernails and onychomycosis of toenails were found in both patients with hemiplegia and normal controls. However, three conditions (longitudinal reddish striation, neapolitan nails and unilateral clubbing) were only observed in some patients, always affecting fingernails of the limb affected by hemiplegia. Neapolitan nails were present in three (3%) patients with hemiplegia which had its onset 3-14 months earlier. Hemiplegia had occurred approximately 40 months earlier, on average, in six patients (6%) with longitudinal reddish striation, and 60-120 months prior to unilateral clubbing in another two patients (2%). CONCLUSIONS: In this study we were able to assess the presence of three different fingernail conditions that were characteristically associated with hemiplegia (longitudinal reddish striation, neapolitan nails and unilateral clubbing), to evaluate their incidence and to study the delay with which these changes occur after a stroke.

Adult↗
PubMed2001

Somatosensory evoked potentials in patients affected by unilateral cerebrovascular lesions with onset during the perinatal period or adulthood.

Unilateral cerebrovascular lesions occurring during adulthood have been reported to be accompanied by high-amplitude somatosensory evoked potentials over the nonaffected hemisphere; however, the mechanisms by which somatosensory evoked potential amplitude increases over the nonaffected hemisphere are still unclear. To investigate the eventual presence of similar amplitude abnormalities in children, we recorded somatosensory evoked potentials in three groups of patients: one with unilateral cerebrovascular lesions that occurred during the perinatal period and another two with unilateral cerebrovascular lesions occurring during late adulthood or old age. Group 1 was comprised of 12 children and young adults (age range 2 3/12-31 years, 6 males and 6 females) who suffered from unilateral cerebrovascular lesion with perinatal onset. Four control groups were arranged with age matched to that of the patients. Adult patients were subdivided into two subgroups (group 2: n = 10, all males; group 3: n = 18, 12 males and 6 females) on the basis of the presence or absence of sensory impairment over the hemiplegic side. In group 1, the four youngest subjects, aged less than 6 years, were found to show somatosensory evoked potentials of abnormally high amplitude over the nonaffected hemisphere, with a "giant" main negative wave at around 45 ms (range 38.7-49.2), strictly localized over the central areas contralateral to the lesion; in normal controls, there was no such wave. All patients in group 2 were found to be affected by large infarctions in the territory of the middle cerebral artery, whereas patients in group 3 presented with subcortical lesions of the internal capsule isolated or in association with an involvement of the frontal and/or temporal cortex. Regarding somatosensory evoked potential parameters measured over the nonaffected hemisphere in adult/elderly subjects, a significant difference was observed for N20 and P22 latency, which was longer in both groups of patients than in controls. There is a significant difference in the neurophysiologic consequences of unilateral cerebrovascular lesion, as well as over the nonaffected hemisphere, if it occurs during early infancy or during adulthood. Our findings show a new type of "giant" somatosensory evoked potentials in some children affected by unilateral cerebrovascular lesion with perinatal onset.

Adolescent↗
PubMed2000

Eyelid myoclonia with absences in three subjects with mental retardation.

Eyelid myoclonia with absences is a rare epileptic syndrome, characterized by eyelid myoclonia, absences, and photosensitivity. On the basis of its clinical and EEG features, this syndrome has been classified as a specific new entity among the idiopathic generalized epilepsies. We report three subjects, aged 4, 16, and 31 years, respectively, with eyelid myoclonia, and absences, mental retardation and other abnormalities of the central nervous system. Our findings suggest that, at least in some cases, eyelid myoclonia and absences can represent a peculiar phenomenon of symptomatic epilepsies.

Adolescent↗
PubMed2000

Sleep in subjects with autistic disorder: a neurophysiological and psychological study.

Polysomnography (EOG, EEG, EMG) was carried out in 17 male children and adolescents with autistic disorder, in seven patients with mental retardation and fragile X syndrome, and in five age- and sex-matched normal male subjects. Density of rapid eye movements was not significantly different in the three groups of subjects; however, some sleep parameters such as time in bed, sleep period time, and total sleep time were significantly lower in subjects with autistic disorder than in normal controls; moreover, patients with autistic disorder showed values of sleep period time, first REM latency and percent (%) sleep stage 1 lower than those of patients with fragile X syndrome with mental retardation. Density of muscle twitches was significantly higher in patients with autistic disorder than in normal controls. In contrast only minor differences were observed between patients with autistic disorder and those with fragile X syndrome with mental retardation. Furthermore, some psychoeducational profile-revised items such as perception and eye-hand coordination, showed significant correlation with some sleep parameters (time in bed, sleep latency, stage shifts, first REM latency and wakefulness after sleep onset). Childhood Autism Rating Scale (CARS) scores to visual response and non-verbal communication showed significant correlation with some tonic sleep parameters, such as sleep period time, wakefulness after sleep onset, and total sleep time. Relating to people and activity level items were found to be significantly correlated with rapid eye movement density. Our results suggest the existence of a sleep pattern in autistic patients different from that observed in subjects with mental retardation and from that of normal controls. In addition, these findings indicate that sleep parameters in these patients are correlated with some psychological indices generally used for the diagnosis of autistic disorder; for this reason, polysomnographies might be useful in the comprehension of the neurophysiological mechanisms underlying this condition.

Adolescent↗
PubMed2000

The time course of high-frequency bands (15-45 Hz) in all-night spectral analysis of sleep EEG.

OBJECTIVE: The EEG spectral content of all-night sleep recordings obtained in 7 healthy young subjects, aged 18-20 years, including frequencies up to 45 Hz, was studied in order to detect eventual changes in the high-frequency range similar to those reported by magnetic field recording during REM sleep at 40 Hz. METHODS: For this purpose, power spectra were calculated with a fast Fourier transform and the power of the bands ranging 0.75-4.50 Hz (Delta), 4.75-7.75 (Theta), 8.00-12.25 (Alpha), 12.50-15.00 (Sigma), 15.25-24.75 (Beta), 25.00-34.75 (Gamma1), and 35.00-44.75 (Gamma 2) was calculated for-the whole period of analysis (7 h). Also two additional time series: the ratio between Beta and Gamma2, and between Gamma1 and Gamma2 were calculated (Beta and Gamma ratios). RESULTS: Beta and Gamma1 showed small changes with a tendency to increase during REM sleep; Gamma2, on the contrary, showed small changes with a tendency to decrease during REM sleep. Beta and Gamma ratio peaks were clearly correlated with the occurrence of REM sleep. The small changes shown by Beta, Gamma1 and Gamma2 were not statistically significant; on the contrary, Beta ratio and Gamma ratio showed the most important statistical significance values being highest during REM sleep and lowest during slow-wave sleep. Finally, the calculation of the linear correlation coefficient and of the cross-correlation between the different bands showed a clear reciprocity between Delta and Beta and Gamma ratios. CONCLUSIONS: Our study shows a new method for the analysis of high frequencies (up to 45 Hz) in the scalp-recorded sleep EEG which allowed us to better define, as compared to previous studies on the same topic, the changes in power characteristically associated with REM sleep and correlated with the REM/non-REM ultradian rhythm, and to propose it as a tool for future studies.

Activity Cycles↗