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G Rosadini

Publications and source records attributed to G Rosadini.

At least 37 records · Page 2Linked to original sources
PubMed1992

An EEG computerized system for the evaluation of hypnotic drugs.

Digital recording of sleep EEG allows computer analysis and quantitative evaluations of sleep disorders and pharmacological effects. A system for polygraphic signal acquisition and storage, which performs a Fourier transform to compute series of spectra representing the evolution of EEG frequency composition through different sleep stages is described. The time course of spectral descriptors like relative band power is used to study the cyclic patterns of sleep and to compute the DSRI (Delta Sleep Regularity Index), a synthetic measure of sleep quality. The method is compared with conventional sleep scoring and examples of applications to normal, pathological and pharmacological conditions are shown. The topographical distribution of spectral parameters is analyzed by means of mapping techniques, allowing the detection of regional variations of EEG in specific pharmacological conditions.

Brain Mapping↗
PubMed1992

Placebo effects in standard human neuropharmacological studies: effects of physiological variations of blood glucose and ammonia concentration on the electrophysiology of the visual system.

The effects on retinal and cortical visual evoked phenomena of the stimulus intensity/spatial frequency and of the spontaneous, physiological blood glucose/ammonia fluctuations were investigated comparatively in a pilot study on young male volunteers. Flash ERG and flash OPs to 5 different stimulus intensities and pattern VECP to 3 spatial frequencies were recorded at 2-hour intervals during a standard acute pharmaco-EEG experimental session (8 h) with administration of placebo; glucose and ammonia blood concentration levels were assessed concomitantly. The effects of the stimulus intensity/spatial frequency were statistically defined for each amplitude/latency measure by nonlinear regression analysis and were removed by computing the residuals from the regression function, which were then tested separately versus the glucose/ammonia concentration by linear regression. Glucose/ammonia statistically significant effects on the visual system were detected at concentration levels within the range of normality and were representative of a nonnegligeable portion of the data overall variance. These effects were selective on retinal/cortical evoked phenomena and it is conceivable that physiological or pathological metabolic changes might account for a still underestimated source of individual variability in human neuropharmacological studies otherwise adequately controlled.

Adult↗
PubMed1991

Effects of beta-adrenoreceptor antagonists on cerebral blood flow of cirrhotic patients with portal hypertension.

The current study evaluated the effect of two beta adrenergic-blocking agents, propranolol (PRP) and atenolol (ATN), versus placebo on cerebral blood flow (CBF) of three homogeneous groups of cirrhotic patients with portal hypertension. CBF was measured by the noninvasive 133-Xenon inhalation method at rest and 1 hour after a single oral dose of PRP (40 mg), or ATN (100 mg), or placebo. Blood pressure and heart rate (HR) were measured at the beginning of each examination, and end-tidal pCO2(PeCO2) was monitored. The HR decreased significantly in both the PRP and ATN groups (P less than .01), whereas no changes were recorded for both PeCO2 and mean arterial blood pressure (MABP). The comparisons of the CBF differences among groups (ANOVA with the significance levels adjusted by the Bonferroni's correction) showed a significant increase in CBF after ATN as compared with both placebo (P less than .02) and PRP (P less than .01), whereas no significant differences were seen after PRP as compared with placebo. Our results confirm that PRP does not significantly affect CBF, whereas ATN induces an increase in CBF, although the underlying mechanism is difficult to explain.

Adrenergic beta-Antagonists↗
PubMed1991

Regional cerebral blood flow asymmetries in a group of 189 normal subjects at rest.

Regional cerebral blood flow (rCBF) asymmetries were studied in 189 subjects (96 males and 93 females) at rest with the 133Xenon inhalation method using a fixed detector system. rCBF asymmetries in the resting condition were very small, nevertheless a significant (p less than 0.001) effect for their topographical distribution was present, reflecting higher rCBF in the right fronto-temporal and left parieto-occipital regions. rCBF asymmetries were not correlated with age, and there were no significant differences between males and females. Asymmetries are therefore useful from a statistical point of view in detecting rCBF abnormalities in the resting condition: they are more stable than absolute values in normal subjects and no matching according to age or sex is required when statistical comparisons are performed.

Adolescent↗
PubMed1991

Spinal cord stimulation and cerebral haemodynamics.

An increase of regional cerebral blood flow (rCBF) has been shown to occur in man during spinal cord stimulation (SCS) by Hosobuchi (1986) and by Meglio et al. (1988) using the 133-Xenon wash-out technique. In this paper we report the effects of SCS on CBF as measured by two different techniques: 8 patients were studied with the 133-Xe method and 28 with the transcranial doppler sonography (TCD), in two cases both studies were performed. The aim of our study was to: 1-verify the effect of SCS on CBF, 2-compare observations made by two different methods, and 3-evaluate a possible correlation between the stimulated spinal segmental level and the modification of CBF. The results of our study confirm that SCS interacts with the mechanisms of regulation of CBF. The stimulation of different spinal cord levels in the same patient can produce different effects and such effects are reproducible. An increase of CBF is more likely to occur with the stimulation of the cervical spinal cord. In patients studied by both methods the sign of CBF changes induced by SCS was the same. Finally, in two patients the effect of SCS on CO2 autoregulation was studied with TCD. The results of such a study, although preliminary, suggest that CO2 and SCS have a competitive effect upon the mechanisms of regulation of CBF.

Blood Flow Velocity↗
PubMed1991

Brain functional imaging in senile psychopathology.

Quantified electroencephalogram (EEG) and regional cerebral blood flow (rCBF) measurements are reliable and currently employed techniques in the functional exploration of the aging brain; they can be routinely employed, since discomfort to the patient is minimal. Topographical analysis of EEG and rCBF results is performed in our laboratory by a fully automated mapping system, which also enables statistical comparisons in real time. The goal of our study is to ascertain if there are systematic modifications in the topographic distribution of rCBF and EEG parameters in normal aging, dementia, cerebrovascular disease and in conditions of increased risk for cerebral pathology (e.g. hypertension). Dementias and cerebrovascular pathologies present characteristic brain functional abnormalities, which can be detected by comparing the patient data to an age-matched normal population by the appropriate statistical tests; therefore, the accurate selection of healthy aged controls appears as a crucial issue in order to improve the sensitivity of statistics.

Adult↗
PubMed1991

Judo and choking: EEG and regional cerebral blood flow findings.

Ten judoka were examined at rest by EEG and regional Cerebral Blood Flow (rCBF) (133-Xenon inhalation method); in seven of them a syncope was induced by choking and EEG was recorded during the loss of consciousness while rCBF was measured immediately after recovery. Baseline EEG and rCBF examinations were normal. During choking, EEG showed diffuse 2-3 Hz. high voltage waves, predominantly in the anterior regions, then the EEG gradually recovered to normal. After choking, rCBF decreased in all but one subject, slightly in four and more markedly in two. Our findings suggest that there is no evidence of permanent CNS functional changes due to judo practice and choking. The variable rCBF features soon after choking-induced syncope may reflect a different timing of recovery from cerebral ischemia for each subject.

Adolescent↗
PubMed1990

Regional cerebral blood flow after omental transposition to the ischaemic brain in man. A five year follow-up study.

Regional cerebral blood flow, recorded by the 133Xenon inhalation method, was measured preoperatively and over a five years postoperative period in six patients with completed stroke and stabilized neurological deficits, who had undergone omental transposition for revascularization of the ischaemic brain. Comparisons of the preoperative blood flow values with those recorded following surgery demonstrate a postoperative increase of blood flow in five patients, with a high statistical degree of significance in four of them at the final examination. The flow increase was noted over the infarcted areas of the brain, upon which the omentum had been placed, as well as areas of the ischaemic hemisphere without omental placement and the contralateral hemisphere. Out of the five patients who demonstrated preoperative flow values below the expected norm for age, four showed final postoperative cerebral blood flow within the normal limits for their age. The results are consistent with the assumption that the transposed omentum played a role in postoperative blood flow increase, by adding collateral circulation to the ischaemic brain.

Adolescent↗
PubMed1990

Primary dysautonomia: cerebral blood flow and hemodynamic findings. Case report.

In a man with orthostatic and effort syncopes due to primary dysautonomia, we measured cerebral blood flow (CBF)--by the 133-Xenon inhalation method--in supine and in sitting positions, and after the i.v. administration of Acetazolamide, a potent cereal vasodilator. Heart rate (HR) and blood pressure (BP) were monitored over the 24 hours by a non-invasive device. The CBF was normal in supine position and significantly reduced when the patient was sitting. Despite che sympathetic denervation, good response to acetazolamide infusion was seen. BP changed with the position of the subject according to gravity, and HR was unresponsive to orthostatic and effort stimuli.

Acetazolamide↗
PubMed1990

Acute effects of acetyl-L-carnitine on regional cerebral blood flow in patients with brain ischaemia.

Ten male patients with brain ischaemia were studied. Regional cerebral blood flow (rCBF) was measured in the resting condition and 1 h after intravenous infusion of 1500 mg acetyl-L-carnitine. rCBF values were compared to those of a control population of the same age decade by a computer mapping system of our own design, which enables rapid visual inspection of cerebral blood flood values distribution and of statistical significance of differences. Beneficial effects of the drug were observed in at least four patients, especially in the affected hemisphere, in another four, rCBF elevations in the areas which were lowest on resting examination were observed, which was paralleled by reductions in surrounding zones. In two patients no modification of rCBF values after acetylcarnitine was seen.

Acetylcarnitine↗
PubMed1989

Cerebral blood flow and plasma free tryptophan in cirrhotics with and without hepatic encephalopathy.

Cerebral blood flow (CBF), measured by the non-invasive 133-Xenon inhalation method, plasma levels of ammonia (NH3) and free tryptophan (fTRP) were determined in 30 cirrhotic patients without overt encephalopathy. Psychometric evaluation detected subclinical hepatic encephalopathy (SHE) in 20 of them, and was normal in the other 10. A significant CBF difference (p less than 0.05) was found between the SHE and the non-SHE patients. fTRP levels were significantly (p less than 0.05) higher in patients with SHE than in those without SHE, and a significant negative correlation (p = 0.003) was found between CBF values and fTRP in the whole group of patients. NH3 did not differ in the two subgroups and did not correlate with CBF values. It is concluded that CBF could have some implications in SHE, although its relevance is still unclear. The negative correlation between CBF and fTRP prompts further investigation concerning the relationships between plasma fTRP, brain serotonin, cerebral metabolism and blood flow in the development of brain derangement during cirrhosis.

Adult↗
PubMed1989

Regional cerebral blood flow and anxiety: a correlation study in neurologically normal patients.

Regional CBF (rCBF) was evaluated by the 133Xe inhalation method in 60 neurologically normal patients (30 men and 30 women) and hemispheric and regional values were correlated with anxiety measurements collected by a self-rating questionnaire before and after the examination. Statistically significant negative correlations between rCBF and anxiety measures were found. rCBF reduction for high anxiety levels is in line with results previously reported by others and could be related to lower performance levels for moderately high anxiety scores as those reported in the present population. This could perhaps be explained by rearrangement of flow from cortical zones to deeper areas of the brain, classically known to be implicated in the control of emotions. However, these results should be interpreted cautiously, since they were obtained in patients and not in normal subjects.

Adult↗
PubMed1989

Evaluation of cerebral blood flow data in stroke patients using a mapping system.

We retrospectively examined regional cerebral blood flow values in 78 patients in the stabilized phase of stroke to evaluate the consistency of lateralization compared with computed tomographic imaging. Examinations were performed using the xenon-133 inhalation technique, and the data were processed and displayed by a computer-assisted system of our own design that allows statistical analysis in real time and is suitable for clinical use. The consistency of lateralization correlated with computed tomographic findings was tested for absolute values, percent distribution, and asymmetries. The latter yielded the highest degree of sensitivity (in 83.3% of the patients the affected hemisphere was correctly identified). Absolute values showed at least one hypoperfused area in the affected hemisphere in 48.7% of the patients, and percent distribution did so in 57.7%. Furthermore, the combination of the three methods of data analysis yielded a sensitivity of 91%; the remaining 9% of the patients, however, exhibited some abnormalities of regional cerebral blood flow (bilateral or contralateral hypoperfusion). Although good agreement was found for lateralization by computed tomography and by the combined use of the three methods of analysis, a complete overlap between functional and structural examinations should not be expected. Problems concerning the sensitivity of the xenon-133 inhalation technique under conditions of low blood flow and the statistical analysis of regional cerebral blood flow data are discussed.

Administration, Inhalation↗
PubMed1988

Effects of intravenous L-acetylcarnitine on retinal oscillatory potentials.

L-acetylcarnitine is a compound with cholinergic properties and putative action on the visual system and the glucose metabolism. Ten healthy, emmertropic volunteers (age range: 21 to 28 years) were studied. Each subject was administered 5, 10, and 30 mg/kg acute intravenous doses of L-acetylcarnitine and matching placebo. Retinal oscillatory potentials to full-field flash stimulation were recorded before and 30, 60, and 120 min after administration. A systematic reduction of the implicit time of the P2 and N2 oscillatory potential components was observed after administration of the 10 and 30 mg/kg doses: significant changes were not evident at the 5 mg dose or after placebo. The latency reduction was significantly correlated with the postdrug increment of the L-acetylcarnitine plasma concentration. No other systematic modification in latency of amplitude was observed.

Acetylcarnitine↗
PubMed1988

Sex differences in regional cerebral blood flow.

Regional cerebral blood flow was measured by the 133-xenon inhalation method during resting in 38 healthy men and 38 healthy women matched pairwise for age in the range 18-72 years. The results showed 11% higher global flow level in the women in all ages. A similar and significant regression of flow by age was seen for both sexes. The regional flow distribution also showed some sex-related differences. Frontal regions showed an asymmetry in the men with higher values on the right side. The female flows were more symmetric. As a hypothesis, it is suggested that the higher flow level in women may be a systemic phenomenon. In fact, other authors have found a higher cardiac index in females. The sex differences in regional flow pattern might be due to differences in the functional organization of the cortex and/or to differences in the mental processes of the "resting" state.

Adolescent↗
PubMed1987

Effects of scopolamine parenteral administration on the electroretinogram, visual evoked potentials, and quantitative electroencephalogram of healthy volunteers.

Single intramuscular doses of scopolamine and matching placebo were administered to young, healthy, and emmetropic volunteers. Electroretinograms and visual evoked potentials (flash and pattern stimuli) were recorded prior to and 30, 90, and 120 min after administration. The effects of scopolamine at the central nervous system level were monitored also by quantitative electroencephalographic methods. Scopolamine reduced the peak-to-peak amplitude of the late components of the flash-evoked potential without affecting latencies. A decrease of the N75 latency and increment of N175 latency of pattern-evoked potentials were observed without any apparent modification of the amplitude values. These changes were not produced by administering topical cyclopentholate. Electroencephalographic effects were apparent with a longer delay after administration than were those on the visual evoked potentials. No significant modification was observed in the electroretinogram under these recording conditions.

Adult↗