Search PubMed⌕ Search

Biomedical subjects

S Seri

Publications and source records attributed to S Seri.

At least 37 records · Page 2Linked to original sources
PubMed1998

Frontal lobe epilepsy associated with tuberous sclerosis: electroencephalographic-magnetic resonance image fusioning.

We studied the topographic relationships between cortical and subcortical lesions shown on magnetic resonance images (MRI) and sources of epileptiform activity in a series of nine children with intractable epilepsy and tuberous sclerosis complex. Although video-electroencephalographic (EEG) monitoring was suggestive of a frontal seizure onset, interictal EEG was, in seven of nine cases, in the form of apparently bisynchronous discharges. In all cases, the use of a short time lag estimation procedure based on a nonlinear correlation function between surface recorded EEG signals allowed the detection of a lateralized onset of EEG paroxysmal activity. Furthermore, a computerized method based on a source localization EEG-MRI image fusioning procedure, has revealed a topographic concordance between well-defined frontal cortical lesions shown on MRI and site of onset of paroxysmal discharges. Lennox-like EEG patterns frequently reported in children with tuberous sclerosis complex could be the result of the tendency of frontal tubers to induce secondary bilateral synchrony, with implications in the medical and eventually surgical management of the often drug-resistant associated seizures.

Child↗
PubMed1997

Extracranial localization of intracranial interictal epileptiform activity using LORETA (low resolution electromagnetic tomography).

Besides the standard clinical methods of EEG waveshape analysis, mathematical models for reconstruction of dipolar sources from the digitized surface EEG have been introduced in epilepsy research. Although useful for localizing focal sources, these methods are inadequate for analyzing widespread epileptiform activity. A recently introduced alternative method called LORETA (low resolution electromagnetic tomography, Pascual-Marqui et al., 1994), directly computes the current distribution throughout the full brain volume, assuming that neighboring neuronal populations are simultaneously and synchronously activated. In mathematical terms the method selects the smoothest of all possible 3-dimensional current distributions, inherently introducing a certain amount of dispersion. In 7 patients, undergoing simultaneous EEG recording from 10 intracranial (subdural) and 22 extracranial electrodes, 111 subdural discharges (61 subtemporal and 50 lateral temporal) were identified. The exact time point of maximal intracranial activity was automatically identified, and the LORETA solution at that timepoint was computed from the surface EEG. Statistical comparison revealed significantly higher LORETA current density in the area corresponding to the subdurally recorded spike compared to other areas, and a more anterior and more medial LORETA location for subtemporal compared to lateral temporal spikes. This study indicates that the LORETA technique may become a useful method to localize electrical activity in the brain.

Adolescent↗
PubMed1996

Trace element content in human milk during lactation of preterm newborns.

The present study has been finalized to perform the content of Zn, Cu, Cr, Se, Mn, F, Mo, Ni, and B in the preterm human milk over 21 d of lactation. Trace element (TE) contents were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-MS), and median concentrations of Zn, Cu, Cr, Se, Mn, and F observed in preterm milk did not demonstrate significant differences in comparison to levels shown in term milk. A statistical significant difference (p < 0.05) has been found among Mo, Ni, and B content in preterm milk for every stage of lactation. TE content of infant blood founded concentrations of Mo in preterm babies significantly (p < 0.01) lower than in term offsprings. Similar values of other TE content were obtained in blood of preterm and term newborns. These findings point to the need for a considerable reassessment of the existing dietary recommendation for Mo content in infant feeding.

Adult↗
PubMed1996

Magnetic resonance imaging of cold injury-induced brain edema in rats.

The chronological changes of blood-brain barrier disruption, and diffusion and absorption of edema fluid were investigated in rats with cold-induced brain injury (vasogenic edema) using magnetic resonance imaging. Contrast medium was administered intravenously at 3 and 24 hours after lesioning as a tracer of edema fluid. Serial T1-weighted multiple-slice images were obtained for 180 minutes after contrast administration. Disruption of the blood-brain barrier was more prominent at 24 hours after lesioning than at 3 hours. Contrast medium leaked from the periphery of the injury and gradually diffused to the center of the lesion. Contrast medium diffused into the corpus callosum and the ventricular system (cerebrospinal fluid). Disruption of the blood-brain barrier induced by cold injury was most prominent at the periphery of the vasogenic edema. Edema fluid subsequently extended into the center of the lesion and was also absorbed by the ventricular system. Magnetic resonance imaging is a useful method to assess the efficacy of therapy for vasogenic edema.

Animals↗
PubMed1994

Computerized electroencephalographic assessment of congenital brain infarction.

We studied 12 children (8 female and 4 male) aged 2.2-14.3 years, whose computed tomographic (CT) examination had shown evidence of malacic and/or porencephalic outcomes of early vascular brain infarction. Topographic spectral electroencephalographic (EEG) analysis was performed in all patients in the awake state. The following spectral EEG variables were studied: topography, absolute and relative power of delta, theta, alpha, beta bands, overall power, and peak alpha frequency asymmetries. The results of topographic spectral EEG analysis were compared with the localization and nature of lesions as detected by CT scans. Depending on the nature of the lesions, we were able to identify two different spectral patterns. Porencephalic cysts were characterized by an increase in delta and theta bands in the areas surrounding the lesion sites, as identified by CT. Spectral EEG patterns of malacic outcomes resulted in a focal increase in theta and delta band power, corresponding to the topography of lesions. Moreover, in 9/12 subjects an asymmetry of alpha rhythm in occipital leads was found homolaterally to the lesion sites, associated with a decrease in power, without any CT evidence of an occipital lesion.

Adolescent↗
PubMed1994

Quantitative EEG modifications during the Cold Water Pressor Test: hemispheric and hand differences.

In a study designed to investigate the neurophysiological correlates of the Cold Water Pressor Test, a standardized experimental model of tonic pain, spectral EEGs were examined during the test in 15 young right-handed adults. Each subject performed a "cold water" and a "warm water" session. The subject immersed in cold water (0 degree C) either the right or the left hand alone, in a randomized way. EEG activity was recorded for an initial 3 min baseline and for the first and second minute epochs after immersion. A further EEG recording was obtained after a 30-min rest. Pain intensity was measured with a visual analogue scale. The EEG recordings showed several patterns of cortical activation during the test. Alpha 2 desynchronization was more evident on the contralateral parietal electrodes of the stimulated hand and lasted longer over all the right hemisphere. Delta activity increased bilaterally, predominantly in the frontal leads. Stimulation of the left hand resulted in a higher delta increase during the second minute after immersion.

Adult↗
PubMed1994

Effects of defined formula diets with and without fibre on ultratrace mineral serum levels in rats.

34 female Sprague-Dawley rats were randomly divided to receive one of 3 diets; a standard diet, a defined formula diet (DFD) or DFD plus fibre, which were administered through a catheter using a pump infusion system. Serum levels of selenium, molybdenum, and chromium were measured before and after 4 weeks of the respective diets. Rats fed the standard diet adequately maintained serum levels of the 3 minerals, but in those fed DFD the levels were reduced. Selenium levels declined by 14.5% in rats fed DFD and by 23.4% in rats fed DFD plus fibre. Molybdenum levels decreased by 23.6% and 22.8% in rats fed DFD with and without fibre, respectively. Chromium levels decreased by 45.5% in rats fed DFD and by 67.7% in rats fed DFD plus fibre. These results corroborate previous evidence that prolonged enteral or parenteral feeding may deplete ultratrace minerals and suggest that addition of ultratrace minerals to DFD may be beneficial.

Journal Article↗
PubMed1993

Computerized EEG topography in childhood migraine between and during attacks.

Topographic EEG mapping was performed in 58 migrainous children (mean age: 12.9 years; 39 without, 19 with aura) between attacks. Ten children were also recorded during an attack with visual aura. Between attacks there were no significant differences between migraineurs and age-matched controls. During visual aura a decrease in occipital alpha power contralateral to the affected hemifield was found in all patients. This was followed by a bilateral frontal increase in delta power, and, during the headache, by an increased delta activity in posterior-temporal and occipital electrode sites. The possible brain mechanisms underlying these EEG changes are discussed.

Adolescent↗
PubMed1993

Effects of zinc on hepatic ornithine transcarbamylase (OTC) activity.

The aim of the study was to examine the effects of oral zinc supplementation on liver ornithine transcarbamylase activity (OTC), a key enzyme in the urea cycle, in cirrhotic rats. OTC was studied in two groups of rats treated with carbon tetrachloride (CCl4): the first received zinc in the drinking water during the induction of cirrhosis; the second was the control group. Cirrhotic rats which received zinc supplementation showed an increase in liver OTC activity, positively correlated with serum and hepatic zinc content. The results suggest that zinc dietary supplementation may modify hepatic OTC activity and, therefore, plasma ammonia levels in cirrhotic rats.

Ammonia↗
PubMed1992

Study of lipid changes in freeze-dried fish during storage. I. The interaction of relative humidity and tissue lipids.

Several studies on lipid stability of freeze-dried fish pointed out the relationship between relative humidity (RH) and autoxidation of highly unsaturated fatty acids. The present study shows the changes of tissue lipids in two different fish, freeze-dried and stored under various RH conditions. Fillets of Scomber scomber L and Sardina pilchardus sardina were freeze-dried and stored for 1, 3, 6 and 9 months. periodically, the sample of both fish were analyzed to evaluate the autoxidation of lipids. The results show that the autoxidation of lipids is quicker during 1st-3rd month of storage, while in a high humidity environment the tissue lipids change slower. According to these results both time of storage and relative humidity must be controlled to maintain the nutritive value of freeze-dried fish.

Animals↗
PubMed1992

Comparison of three different methods for evaluation of Helicobacter pylori (H.P.) in human dental plaque.

Helicobacter pylori (H.p.) is a microorganism involved in peptic ulcer disease. To clarify the role of human dental plaque as a reservoir of H.p. and to compare different methods of investigation the authors studied 20 patients, 17 males main age 56 +/- 12 and 3 females 52 +/- 7, gastro-duodenal H.p. positive. The trial was carried out by cultural, biochemical and microscopical plaque analysis. Cultural and microscopical method were H.p. positive in 80% patients, urease in 100%, alkaline phosphatase in 80%, gamma glutamyltransferase in 70%, nitrate in 70%. To minimize the possibility of false results in H.p. plaque analysis it is necessary to use the three methods simultaneously. Further trials both on human plaque and on food and beverages will be useful to clarify the role of H.p. in human pathology.

Adult↗
PubMed1991

Tuberous sclerosis: relationships between topographic mapping of EEG, VEPs and MRI findings.

A group of 10 patients suffering from tuberous sclerosis (TS) and epilepsy was studied by means of topographic mapping of EEG and visual evoked potentials. The localizing ability of the technique was compared to the topography of hyperintense T2-dependent areas seen on magnetic resonance images (MRI). Data were collected from 19 electrodes, free from interictal EEG transients and artifacts, spectral analysis was performed using the FFT algorithm and color maps were produced by specialized equipment. Data were analyzed with respect to the presence of interhemispheric asymmetries and significant differences with age-matched normal controls. The topography of slow frequency components was the best clue for localization, with a concordance between imaging and spectral EEG data in 76% of the lesions detected by MRI. In 7 patients topographic mapping revealed spectral abnormalities in areas where MRI was not able to detect morphological lesions. These abnormalities were characterized by an increased delta (5 patients), theta (4 patients), or lowered ipsilateral alpha (1 patient) power. Although full agreement between imaging and electrophysiological data was not observed, we believe that in patients with TS the study of EEG rhythm activity can add valuable information to the visual inspection of the tracings.

Adolescent↗
PubMed1989

Laterality of arm movement in full-term newborn.

We have investigated 20 healthy full-term newborns between the 4th and the 6th day of life in standard conditions for laterality of arm movements, before and after introduction of a target. The durations of recording were: (a) 5 min continuously before target introduction; (b) five 1-min units during target presentation. The movements studied were extension, flexion, movement with semiflexed arm with hand half-open or open toward the midline of the body, and total movements. Each of these items were counted separately and the counts were compared within and between sides. Spontaneous movements showed no side preference whereas in the presence of the target, movements toward the midline (target directed movements) showed a significant right-hand preference.

Arm↗
PubMed1989

Carbon tetrachloride-induced experimental cirrhosis in the rat: a reappraisal of the model.

The goal of this study was to evaluate the presence of extrahepatic damage and the uniformity and reversibility of the histological findings in CCl4-induced liver cirrhosis in the rat. To verify these findings rats were sacrificed 2 and 10 weeks after a treatment consisting of ten intragastric doses of CCl4, administered weekly. All treated rats developed an irreversible micronodular cirrhosis with no damage to the brain, kidney and pancreas. Moreover, rats sacrificed 2 weeks after the last CCl4 dose showed a number of functional alterations usually observed in man. In particular, low branched chain/aromatic amino acids (BCAA/AAA) plasma ratio, high ammonia, low zinc and high insulin with normal blood glucose were obtained.

Amino Acids↗
PubMed1989

Effects of low-fat diets on gastric stress-induced ulcers after barbiturate administration in rats.

The effect of low-fat diets on appearance of stress-induced gastric ulcers was tested in rats consuming phenobarbital (0.25 ml/100g/day) during 1 week. The results showed a significant increase of the ulcerated area in the stomachs of the rats fed by low-fat diets, versus controls. It seemed that a diet adequate in lipids may decrease the ulcerogenic effects induced by chronic use of phenobarbital.

Animals↗
PubMed1987

Personality inventory for children and childhood migraine. A case-controlled study.

The personality inventory for children (PIC), which is similar in structure to the MMPI and hence free from subjective interpretation, is applicable to children from 6 to 16 years of age. We used it in 40 children with common migraine aged 8 to 14 years and in 40 controls comparable in age, sex, and socioeconomic status. Although the migraine subjects did not emerge as globally different from the controls, they presented significantly higher scores on the Somatic concern, Depression, and Anxiety scales, irrespective of sex. These results underline the value of PIC in the diagnostic assessment of childhood migraine.

Adolescent↗