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Biomedical subjects

M Tettamanti

Publications and source records attributed to M Tettamanti.

At least 19 recordsLinked to original sources
PubMed2006

Evaluating the environmental impact of various dietary patterns combined with different food production systems.

OBJECTIVE: Recent studies support the hypothesis that plant-based diets are environmentally better than meat-based diets. This study aims to further explore this topic and to compare different environmental impacts resulting from different dietary patterns (omnivorous, vegetarian, vegan) and methods of production (conventional farming and organic agriculture). DESIGN: Three weekly balanced diets, equivalent to one another for energetic and nutrient content, have been planned: an omnivorous one, a vegetarian one and a vegan one. For each one, the Life Cycle Assessment (LCA) method has been applied in order to calculate the environmental impact, expressed in 'points'. INTERVENTIONS: The software we selected to carry out the Inventory Analysis and the Impact Assessment is SimaPro5. The Assessment phase has been conducted using Ecoindicator 99, a damage-oriented method, which analyses the impact according to three large damage categories, each of them subsuming various impact categories.

Agriculture↗
PubMed2003

A fMRI study of word retrieval in aphasia.

The neural mechanisms underlying recovery of cognitive functions are incompletely understood. Aim of this study was to assess, using functional magnetic resonance (fMRI), the pattern of brain activity during covert word retrieval to letter and semantic cues in five aphasic patients after stroke, in order to assess the modifications of brain function which may be related to recovery. Four out of five patients had undergone language recovery, according to standard testing, after at least 6 months of rehabilitation. The cerebral activation of each patient was evaluated and compared with the activation pattern of normal controls studied with the same fMRI paradigm. In the patients, the pattern of brain activation was influenced by the site and extent of the lesion, by the degree of recovery of language, as reflected by task performance outside the scanner, and by task requirements. In the case of word retrieval to letter cues, a good performance was directly related to the activation in Broca's area, or in the right-sided homologue. On the other hand, in the case of semantic fluency, the relationship between performance level and activation was less clear-cut, because of extensive recruitment of frontal areas in patients with defective performance. These findings suggest that the performance in letter fluency is dependent on the integrity of the left inferior frontal cortex, with the participation of the homologous right hemispheric region when the left inferior frontal cortex is entirely of partially damaged. Semantic fluency, which engages the distributed network of semantic memory, is also associated with more extensive patterns of cerebral activation, which however appear to reflect retrieval effort rather than retrieval success.

Aged↗
PubMed2002

Supercritical fluid extraction: an innovative tool for a fly ash-like model support.

The performance of the supercritical fluid extraction (SFE) technique to obtain a new and more appropriate model support for PCDD/F formation studies was investigated. To characterize fly ash and model supports and relate their chemical-physical properties, surface area and pore size were determined. To evaluate the influence on reactivity of the different model supports with respect to raw fly ash, a kinetic study of the thermal behavior of dibenzofuran (DF) was performed. Rate constants as well as the activation and thermodynamic parameters for the different systems were also compared. The model support obtained from SFE was very similar to raw fly ash from the structural, physical-chemical, and kinetic points of view.

Benzofurans↗
PubMed2002

Peripheral inflammatory response in Alzheimer's disease and multiinfarct dementia.

Whether peripheral inflammatory molecules can be considered markers of dementia is still an open issue. We have investigated the presence of circulating cytokines and the ability of blood cells to release them in response to an inflammatory stimulus in patients with different types of dementia and in age-matched controls. A significant increase in circulating interleukin-1beta in moderate Alzheimer and in multiinfarct (145 and 224 times control concentration, respectively) dementia and in circulating tumor necrosis factor-alpha concentration in multiinfarct dementia patient group (156%) were found. Tumor necrosis factor-alpha and interleukin-6 released from blood cells after exposure to lipopolysaccharide were significantly reduced in moderate Alzheimer (60%, both cytokines) and multiinfarct patients (71 and 50%, respectively), while interleukin-10 was decreased only in multiinfarct patients (61%). The results show that patients with Alzheimer disease or multiinfarct dementia have an upregulation of circulating cytokines and a downregulation of cytokines released by blood cells.

Alzheimer Disease↗
PubMed2002

Interhemispheric transmission of visuomotor information in humans: fMRI evidence.

Normal human subjects underwent functional magnetic resonance imaging (fMRI) while performing a simple visual manual reaction-time (RT) task with lateralized brief stimuli, the so-called Poffenberger's paradigm. This paradigm was employed to measure interhemispheric transmission (IT) time by subtracting mean RT for the uncrossed hemifield-hand conditions, that is, those conditions not requiring an IT, from the crossed hemifield-hand conditions, that is, those conditions requiring an IT to relay visual information from the hemisphere of entry to the hemisphere subserving the response. The obtained difference is widely believed to reflect callosal conduction time, but so far there is no direct physiological evidence in humans. The aim of our experiment was twofold: first, to test the hypothesis that IT of visuomotor information requires the corpus callosum and to identify the cortical areas specifically activated during IT. Second, we sought to discover whether IT occurs mainly at premotor or perceptual stages of information processing. We found significant activations in a number of frontal, parietal, and temporal cortical areas and in the genu of the corpus callosum. These activations were present only in the crossed conditions and therefore were specifically related to IT. No selective activation was present in the uncrossed conditions. The location of the activated callosal and cortical areas suggests that IT occurs mainly, but not exclusively, at premotor level. These results provide clear cut evidence in favor of the hypothesis that the crossed-uncrossed difference in the Poffenberger paradigm depends on IT rather than on a differential hemispheric activation.

Adult↗
PubMed2001

Thermal oxidation kinetics and mechanism of sludge from a wastewater treatment plant.

The organic fraction of a sludge from a wastewater biological treatment plant is characterized by the total organic carbon, TOC, content, cyclohexane and toluene extractions, and thermal desorptions in nitrogen and air flow at different temperatures. The inorganic fraction is characterized by water extraction, FT-IR spectroscopy, thermogravimetric analysis, and scanning electron microscopy/energy dispersion X-ray analysis. The thermal degradation rate of organic carbon is studied in batch experiments in air, in the 250-500 degrees C temperature range. The sample TOC is used to measure the decrease of reagent concentration with time. The TOC vs time data are well fitted by a generalized kinetic model, previously proposed for the MSWIs fly ash thermal degradation. The rate constants of the immediate carbon gasification, k2, and of the dissociative oxygen chemisorption, k1, followed by C(O) intermediate gasification, k3, together with activation and thermodynamic parameters are calculated. The rate determining step is the C(O) oxidation. The influence of desorbed or extracted organic compounds on kinetics and the role of the C(O) formation in explaining the reaction mechanism as well as the comparison with fly ash kinetics are discussed.

Gases↗
PubMed2001

Remodelling of sensorimotor maps in paraplegia: a functional magnetic resonance imaging study after a surgical nerve transfer.

The adult mammalian brain has the capacity of reorganising its neural connections in response to lesions/modifications of the peripheral and central nervous system. We show in vivo, using functional magnetic resonance imaging (fMRI), that in paraplegics the lower-limb sensorimotor cortex is invaded by the arm representation. This functional reshaping appears to be reversible. Indeed, surgical transfer of the ulnar nerve to the ipsilateral quadriceps and hip muscles allowed their contraction in a paraplegic patient. During fMRI, these voluntary movements activated the hip and thigh representation in sensorimotor cortex. We suggest that the functional recovery of the lower-limb functional maps might have been driven by the restored somatosensory inputs from the reactivated periphery. The voluntary movements of the lower-limbs are regained through the 're-awakening' of the corresponding sensorimotor cortex.

Adult↗
PubMed2001

Syntax and the brain: disentangling grammar by selective anomalies.

Many paradigms employed so far with functional imaging in language studies do not allow a clear differentiation of the semantic, morphological, and syntactic components, as traditionally defined within linguistic theory. In fact, many studies simply consider the brain's response to lists of unrelated words, rather than to syntactic structures, or do not neutralize the confounding effect of the semantic component. In the present PET experiment, we isolated the functional correlates of morphological and syntactic processing. The neutralization of the access to the lexical-semantic component was achieved by requiring the detection of anomalies in written sentences consisting of pseudowords. In both syntactic and morphosyntactic processing, the involvement of a selective deep component of Broca's area and of a right inferior frontal region was detected. In addition, within this system, the left caudate nucleus and insula were activated only during syntactic processing, indicating their role in syntactic computation. These findings provide original in vivo evidence that these brain structures, whose individual contribution has been highlighted by clinical studies, constitute a neural network selectively engaged in morphological and syntactic computation.

Adult↗
PubMed2001

Different brain correlates for watching real and virtual hand actions.

We investigated whether observation of actions reproduced in three-dimensional virtual reality would engage perceptual and visuomotor brain processes different from those induced by the observation of real hand actions. Participants were asked to passively observe grasping actions of geometrical objects made by a real hand or by hand reconstructions of different quality in 3D virtual reality as well as on a 2D TV screen. We found that only real actions in natural environment activated a visuospatial network including the right posterior parietal cortex. Observation of virtual-reality hand actions engaged prevalent visual perceptual processes within lateral and mesial occipital regions. Thus, only perception of actions in reality maps onto existing action representations, whereas virtual-reality conditions do not access the full motor knowledge available to the central nervous system.

Adult↗
PubMed2001

Inflammatory markers in Alzheimer's disease and multi-infarct dementia.

Inflammation has been involved in the pathogenesis of dementia. The study evaluates the presence and the source of pro- and anti- inflammatory cytokines in the blood of patients with Alzheimer's disease (AD), multi-infarct dementia (MID) or in non-demented elderly people (controls). Tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, IL-10, IL-1 receptor antagonist (IL-1Ra) and soluble TNF receptor I (sTNF-RI) plasma concentrations and release from blood cells stimulated with lipopolysaccharide (LPS, 1 microg/ml) were determined. The results show that TNF-alpha released from blood cells is significantly decreased (27%) in all demented patients compared to controls. Circulating TNF-alpha is increased (400%) only in MID patients. In these patients plasma levels of sTNF-RI are increased (53%) and IL-10 from stimulated blood cells decreased (47%) compared to non-demented subjects. The results show that: (1) peripheral production of TNF-alpha is blunted in demented (both AD and MID) patients compared to non-demented age-matched subjects; (2) AD patients have a selective disregulation of the peripheral TNF-alpha system; (3) different cytokines are up- or down- regulated in MID patients showing that in this condition the pro- and anti-inflammatory peripheral cytokine system is more widely affected.

Aged↗
PubMed2001

Acute effect of 3-(4-acetamido)-butyrril-lorazepam (DDS2700) on brain function assessed by PET at rest and during attentive tasks.

The aim of this study was to assess, by positron emission tomography (PET), the effect on cerebral functional activity of a new lorazepam-gamma-aminobutyric acid (GABA) conjugate [3-(4-acetamido)-butyrril lorazepam (DDS2700)]. Ten healthy volunteers were studied by PET and [18F]fluoro-deoxy-D-glucose ([18F]FDG) under baseline conditions and following the administration of DDS2700. Regional cerebral blood flow (rCBF) was measured by PET and 15O-water in three additional participants while they performed attentive tasks, before and after drug administration. DDS2700 induced a decrease in the regional cerebral metabolic rate of glucose (rCMRglu) in the thalamus (-17%), cerebellum (-11%) and caudate nucleus (-8%). The observed effects on glucose metabolism were probably related to the subjective sedation and tiredness reported by the participants. During the attentive tasks, rCBF increased in frontal and temporal regions associated with attentional processing of auditory material. These circuits were no longer active after DDS2700 administration, while rCBF increased in cingulate cortex, occipitoparietal regions, pons and cerebellum. These drug-induced activations might be directly related to intervening sleepiness and to the consequent effort in keeping attention focused on the tasks. The effects of DDS2700 on glucose metabolism at rest, and on rCBF during activation conditions, indicate a drug action on cerebral networks involved in alertness, vigilance and attention maintenance. PET assessment by [18F]FDG and water may provide complementary information in pharmacodynamic studies.

Adult↗
PubMed2000

Analytical characterization of municipal solid waste incinerator fly ash. Part II.

The synergy of the micro FT-IR (Fourier Transform-Infrared) and SEM-EDX (Scanning Electron Microscopy-Energy Dispersive X-ray) techniques has been shown to be particularly helpful and effective for the characterization of inorganic compounds in fly ashes. The experimental data obtained by these techniques have been interpreted in comparison with those of other techniques. The presence of calcium carbonate, some sulfates, ammonium nitrate, calcium hydrogen phosphate, some chlorides, some oxides and aluminium silicates have been verified.

Aluminum Silicates↗
PubMed1999

Word and picture matching: a PET study of semantic category effects.

We report two positron emission tomography (PET) studies of cerebral activation during picture and word matching tasks, in which we compared directly the processing of stimuli belonging to different semantic categories (animate and inanimate) in the visual (pictures) and verbal (words) modality. In the first experiment, brain activation was measured in eleven healthy adults during a same/different matching task for textures, meaningless shapes and pictures of animals and artefacts (tools). Activations for meaningless shapes when compared to visual texture discrimination were localized in the left occipital and inferior temporal cortex. Animal picture identification, either in the comparison with meaningless shapes and in the direct comparison with non-living pictures, involved primarily activation of occipital regions, namely the lingual gyrus bilaterally and the left fusiform gyrus. For artefact picture identification, in the same comparison with meaningless shape-baseline and in the direct comparison with living pictures, all activations were left hemispheric, through the dorsolateral frontal (Ba 44/6 and 45) and temporal (Ba 21, 20) cortex. In the second experiment, brain activation was measured in eight healthy adults during a same/different matching task for visually presented words referring to animals and manipulable objects (tools); the baseline was a pseudoword discrimination task. When compared with the tool condition, the animal condition activated posterior left hemispheric areas, namely the fusiform (Ba 37) and the inferior occipital gyrus (Ba 18). The right superior parietal lobule (Ba 7) and the left thalamus were also activated. The reverse comparison (tools vs animals) showed left hemispheric activations in the middle temporal gyrus (Ba 21) and precuneus (Ba 7), as well as bilateral activation in the occipital regions. These results are compatible with different brain networks subserving the identification of living and non-living entities; in particular, they indicate a crucial role of the left fusiform gyrus in the processing of animate entities and of the left middle temporal gyrus for tools, both from words and pictures. The activation of other areas, such as the dorsolateral frontal cortex, appears to be specific for the semantic access of tools only from pictures.

Adult↗
PubMed1999

The neural correlates of verb and noun processing. A PET study.

The hypothesis that categorical information, distinguishing among word classes, such as nouns, verbs, etc., is an organizational principle of lexical knowledge in the brain, is supported by the observation of aphasic subjects who are selectively impaired in the processing of nouns and verbs. The study of lesion location in these patients has suggested that the left temporal lobe plays a crucial role in processing nouns, while the left frontal lobe is necessary for verbs. To delineate the brain areas involved in the processing of different word classes, we used PET to measure regional cerebral activity during tasks requiring reading of concrete and abstract nouns and verbs for lexical decision. These tasks activated an extensive network of brain areas, mostly in the left frontal and temporal cortex, which represents the neural correlate of single word processing. Some left hemispheric areas, including the dorsolateral frontal and lateral temporal cortex, were activated only by verbs, while there were no brain areas more active in response to nouns. Furthermore, the comparison of abstract and concrete words indicated that abstract word processing was associated with selective activations (right temporal pole and amygdala, bilateral inferior frontal cortex), while no brain areas were more active in response to concrete words. There were no significant interaction effects between word class and concreteness. Taken together, these findings are compatible with the view that lexical-semantic processing of words is mediated by an extensive, predominantly left hemispheric network of brain structures. Additional brain activations appear to be related to specific semantic content, or, in the case of verbs, may be associated with the automatic access of syntactic information.

Adult↗
PubMed1998

The effects of semantic category and knowledge type on lexical-semantic access: a PET study.

Neuropsychological studies of patients with category-specific recognition disorders, as well as PET investigations of semantic category effects in visual recognition tasks, have led some authors to the hypothesis that visual-perceptual knowledge plays a crucial role in the recognition of natural items, such as animals, while functional-associative information is more important for the recognition of man-made tools. To study the cerebral correlates of the retrieval of different types of semantic knowledge about living and nonliving entities, we performed a PET experiment in which normal subjects were required to access visual- and functional-associative information related to visually presented words corresponding to animals and tools. The experimental conditions were the following: (1) Rest. (2) Baseline: letter detection in pseudo-words. (3) Animal, visual knowledge: decide whether the animal has a long or short tail with respect to the body. (4) Animal, associative knowledge: decide whether the animal is typically found in Italy. (5) Tool, visual knowledge: decide whether the object is longer than wider or vice versa. (6) Tool, functional knowledge: decide whether the object is typically used as a kitchen tool. Lexical-semantic access (all lexical conditions pooled) activated the prefrontal cortex on the left and the parietal-occipital junction and posterior cingulate cortex bilaterally. An analysis of the individual experimental conditions in comparison with the nonword baseline showed that accessing visual versus associative knowledge was associated with different activation patterns: predominantly frontal in the case of visual features, temporoparietal for associative knowledge. While the activation patterns involved similar areas for living and nonliving entities, in the case of the latter they were restricted to the left hemisphere. The analysis of main effects confirmed these findings: there were several significant differences in the visual-associative comparison, while category-related differences were less prominent. These findings indicate that the retrieval of different types of knowledge is associated with distinct patterns of brain activation; on the other hand, category-related differences were less evident than in picture matching and naming tasks.

Adult↗
PubMed1997

Drug use by the elderly in Italy.

OBJECTIVES: To evaluate drug consumption in the elderly aged 75 years or more living at home. DESIGN: Cross-sectional study. SETTING: Old-old (i.e., > or = 75 y) people living in central Turin, a city in northern Italy. PARTICIPANTS: Thirty-four general practitioners (GPs), with 50 or more old-old people in their patient list, randomly chosen among the GPs working in the Unità Socio-Sanitaria Locale I (Local Health Unit I) of Turin; 261 old-old people (135 men and 126 women) randomly selected from the practice records. METHODS: Data were collected by the GP through a structured questionnaire during an office visit and by a social worker in a home interview within 14 days of the GP visit. GPs were asked to record every diagnosis and drug currently taken by the patient; social workers were trained in the administration of a structured questionnaire exploring sociodemographic variables, drug use (following the medication inventory strategy), disability, cognitive functions, and depressive symptoms. RESULTS: Nearly all subjects (95% of the women and 91% of the men) were taking at least 1 drug. The overall number of drugs recorded was 917 (47.1% for men and 52.9% for women), of which 172 (18.8%) were not reported by the GP but were recorded during the social worker's visit. The mean number of drugs was 3.2 for men and 3.8 for women, with a statistically significant difference (p = 0.02), while the mean number of diagnoses was 2.3 and 2.6, respectively. The study of correlates of drug consumption showed a strong association with number of diagnoses at univariate analysis (p < 0.0001, with a linear correlation coefficient of 0.64). No multivariate model showed a clear superiority over the simple one containing only the number of diagnoses in predicting the total number of drugs taken. Cardiovascular, nervous system, and alimentary tract drugs were the most frequently used. A total of 107 subjects (41%) were taking at least 1 unreported drug. CONCLUSIONS: Our study shows high drug consumption among old-old people, with nearly 20% of drugs taken not reported by the GP. These results emphasize the need for an essential therapeutic approach in old-old people, prescribing only drugs of scientifically proven efficacy. Furthermore, the GP must make more effort when collecting a drug history from old-old patients.

Aged↗
PubMed1994

Multiple-dose pharmacokinetics and safety of a potential memory-enhancing compound, CL 275,838, in healthy male volunteers.

The pharmacokinetics and safety of CL 275,838, a new potential memory-enhancing compound, were examined after 14 daily doses (50 and 100 mg) in 16 healthy male volunteers, age 20 to 59 years, in a randomized, double-blind, placebo-controlled, parallel group study. Trough blood samples (predose) were collected on days 2, 4, 7, 10, and 14, and further samples were drawn after the final dose (day 14) to define the multiple-dose kinetics of the parent compound and its metabolites II and IV. Intercurrent clinical events, vital functions, EEG, ECG, and cognitive tests (attention, verbal memory, and spatial memory) were considered as outcome measures of safety. Performance in cognitive tests was also studied to collect preliminary information on possible therapeutic action. Predose plasma concentrations of the parent compound and its two metabolites increased approximately in proportion to the dose, and accumulation was complete within 7 days, regardless of the dose. At steady state, mean Cmax and AUC of the parent compound and its two metabolites were dose related. Mean wash-out t1/2 was 18 to 20 hours for the parent compound, 22-23 hours for metabolite II, and 28-33 hours for metabolite IV; these elimination t1/2 are comparable for the two doses, and are similar to those observed in single-dose studies. For the 50-mg-dose group, predicted and observed average plasma concentrations (Css) of CL 275,838 and its two metabolites did not differ significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗