Biomedical subjects

Marco Catani

Publications and source records attributed to Marco Catani.

10 recordsLinked to original sources

PubMed2003

Occipito-temporal connections in the human brain.

Diffusion tensor MRI (DT-MRI) provides information about the structural organization and orientation of white matter fibres and, through the technique of 'tractography', reveals the trajectories of cerebral white matter tracts. We used tractography in the living human brain to address the disputed issue of the nature of occipital and temporal connections. Classical anatomical studies described direct fibre connections between occipital and anterior temporal cortex in a bundle labelled the inferior longitudinal fasciculus (ILF). However, their presence has been challenged by more recent evidence suggesting that connections between the two regions are entirely indirect, conveyed by the occipito-temporal projection system--a chain of U-shaped association fibres. DT-MRI data were collected from 11 right-handed healthy subjects (mean age 33.3 +/- 4.7 years). Each data set was co-registered with a standard MRI brain template, and a group-averaged DT-MRI data set was created. 'Virtual' in vivo dissection of occipito-temporal connections was performed in the group-averaged data. Further detailed virtual dissection was performed on the single brain data sets. Our results suggest that in addition to the indirect connections of the occipito-temporal projection system: (i) a major associative connection between the occipital and anterior temporal lobe is provided by a fibre bundle whose origin, course and termination are consistent with classical descriptions of the ILF in man and with monkey visual anatomy; (ii) the tractography-defined ILF is structurally distinct from fibres of the optic radiation and from U-shaped fibres connecting adjacent gyri; (iii) it arises in extrastriate visual 'association' areas; and (iv) it projects to lateral and medial anterior temporal regions. While the function of the direct ILF pathway is unclear, it appears to mediate the fast transfer of visual signals to anterior temporal regions and neuromodulatory back-projections from the amygdala to early visual areas. Future tractography studies of patients with occipito-temporal disconnection syndromes may help define the functional roles of the direct and indirect occipito-temporal pathways.

Adult↗

PubMed2003

Axonal injury within language network in primary progressive aphasia.

Primary progressive aphasia (PPA) is characterized by an isolated progressive impairment of word use and comprehension reflecting the distribution of pathological processes within the left hemisphere. We used proton magnetic resonance spectroscopy (1H-MRS) to study in vivo the integrity of axonal fibers connecting perisylvian language areas in 11 patients with PPA, 11 subjects with Alzheimer's disease, and 22 controls. Brain metabolites (N-acetylaspartate, myoinositol, choline, creatine) were measured bilaterally within a volume of interest located in the central portion of the superior longitudinal fasciculus, a long associative bundle connecting Broca's area with Wernicke's area, and other language regions of the temporal lobe. In the PPA group, there was an asymmetrical N-acetylaspartate to creatine ratio reduction compared with Alzheimer's disease and controls, with greater changes on the left side. The myoinositol to creatine ratio was increased in the PPA group bilaterally compared with controls. The choline to creatine ratio did not differ among the three groups. These results indicate an asymmetrical focal axonal injury within the language network in PPA. The marked difference in the distribution of N-acetylaspartate to creatine between PPA and Alzheimer's disease suggests that proton magnetic resonance spectroscopy may help to differentiate between these two conditions.

Aged↗

PubMed2003

Validation of the five-item geriatric depression scale in elderly subjects in three different settings.

OBJECTIVES: To test the effectiveness of a five-item version of the Geriatric Depression Scale (GDS) for the screening of depression in community-dwelling older subjects, hospitalized older patients, and nursing home residents. DESIGN: A cross-sectional study. SETTING: A geriatric acute care ward, a geriatric outpatient clinic, and a nursing home. PARTICIPANTS: One hundred eighty-one cognitively intact older subjects. MEASUREMENT: All the participants had a comprehensive geriatric assessment including a neuropsychological evaluation by a geriatrician experienced in the management of depression. The five-item GDS was compared with the 15-item version of the GDS using the clinical diagnosis according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria as the criterion standard. The sensitivity, the specificity, the overall accuracy, positive and negative predictive values, and positive and negative likelihood ratios were calculated. The agreement between each of two different versions of the GDS and the clinical diagnosis and the test-retest and the interrater reliability of the five-item scale were also evaluated. RESULTS: In the whole sample, 48.1% of the subjects were depressed. The five-item GDS had a sensitivity of 0.94 (0.91-0.98), a specificity of 0.81 (0.75-0.87), a positive predictive value of 0.81 (0.75-0.87), a negative predictive value of 0.94 (0.90-0.97), a positive likelihood ratio of 4.92 (4.39-5.5), and a negative likelihood ratio of 0.07 (0.06-0.08). The five-item GDS and the 15-item GDS showed a significant agreement with the clinical diagnosis of depression (kappa = 0.74 for both scales). The five-item GDS had good interrater reliability (kappa = 0.88) and test-retest reliability (kappa = 0.84). Similar values were obtained in each setting and in both sexes. CONCLUSION: The five-item GDS is as effective as the 15-item GDS for the screening of depression in cognitively intact older subjects.

Aged↗

PubMed2003

Cathepsin D polymorphism in Italian elderly subjects with sporadic late-onset Alzheimer's disease.

Alzheimer's disease (AD) is the most frequent cause of dementia in elderly people. Different pathological pathways have been involved in the development of late-onset AD. Among them, numerous genes have been proposed as pathogenetic factors acting independently or interactively. It has been suggested that the cathepsin D gene (CTSD) is associated with late-onset AD. We analyzed an exonic polymorphism of the CTSD gene [C-->T (Ala-->Val) transition at position 224] in 142 AD patients and 120 controls. Our data indicate no significant association between this polymorphism and the risk of AD. Likewise there was no association between CTSD polymorphism and the apolipoprotein E genotype in the risk of developing AD.

Age of Onset↗

PubMed2003

Marked decrease in plasma antioxidants in aged osteoporotic women: results of a cross-sectional study.

Although recent epidemiological studies found a positive correlation between dietary vitamin C intake and bone mineral density, data on plasma levels of vitamin C or other antioxidants in osteoporotic subjects are scanty. The aim of this study was to evaluate whether antioxidant defenses are decreased in elderly osteoporotic women and, if this is the case, to understand whether osteoporosis is a condition characterized by increased oxidative stress. To answer these questions, plasma vitamins C, E, and A; uric acid; and the enzymatic activities of superoxide dismutase in plasma and erythrocytes and of glutathione peroxidase in plasma were measured in 75 subjects with osteoporosis and 75 controls. Dietary and endogenous antioxidants were consistently lower in osteoporotic than in control subjects. On the other hand, plasma levels of malondialdehyde, a byproduct of lipid peroxidation, did not differ between groups. Our results reveal that antioxidant defenses are markedly decreased in osteoporotic women. The mechanisms underlying antioxidant depletion and its relevance to the pathogenesis of osteoporosis deserve further investigation.

Activities of Daily Living↗

PubMed2002

Lymphocyte oxidative DNA damage and plasma antioxidants in Alzheimer disease.

CONTEXT: A large body of experimental evidence suggests that in Alzheimer disease (AD) pathogenesis an important role is played by oxidative stress, but there is still a lack of data on in vivo markers of free radical-induced damage. OBJECTIVES: To evaluate levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative damage to DNA, in peripheral lymphocytes; to measure plasma concentrations of several nonenzymatic antioxidants; and to assess the relationships between any observed changes in lymphocyte DNA 8-OHdG content and plasma antioxidant levels in patients with AD and healthy aged control subjects. SUBJECTS: Forty elderly outpatients with AD and 39 healthy age- and sex-matched controls were studied. MAIN OUTCOME MEASURES: The level of 8-OHdG was determined in DNA extracted from lymphocytes and plasma levels of vitamin C, vitamin A, vitamin E, and carotenoids (zeaxanthin, beta-cryptoxanthin, lycopene, lutein, and alpha- and beta-carotene) were measured by high-performance liquid chromatography. RESULTS: Lymphocyte DNA 8-OHdG content was significantly higher and plasma levels of antioxidants (with the exception of lutein) were significantly lower in patients with AD compared with controls. In patients with AD, a significant inverse relationship between lymphocyte DNA 8-OHdG content and plasma levels of lycopene, lutein, alpha-carotene, and beta-carotene, respectively, was observed. CONCLUSIONS: Markers of oxidative damage are increased in AD and correlate with decreased levels of plasma antioxidants. These findings suggest that lymphocyte DNA 8-OHdG content in patients with AD reflects a condition of increased oxidative stress related to a poor antioxidant status.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2002

Virtual in vivo interactive dissection of white matter fasciculi in the human brain.

This work reports the use of diffusion tensor magnetic resonance tractography to visualize the three-dimensional (3D) structure of the major white matter fasciculi within living human brain. Specifically, we applied this technique to visualize in vivo (i) the superior longitudinal (arcuate) fasciculus, (ii) the inferior longitudinal fasciculus, (iii) the superior fronto-occipital (subcallosal) fasciculus, (iv) the inferior frontooccipital fasciculus, (v) the uncinate fasciculus, (vi) the cingulum, (vii) the anterior commissure, (viii) the corpus callosum, (ix) the internal capsule, and (x) the fornix. These fasciculi were first isolated and were then interactively displayed as a 3D-rendered object. The virtual tract maps obtained in vivo using this approach were faithful to the classical descriptions of white matter anatomy that have previously been documented in postmortem studies. Since we have been able to interactively delineate and visualize white matter fasciculi over their entire length in vivo, in a manner that has only previously been possible by histological means, "virtual in vivo interactive dissection" (VIVID) adds a new dimension to anatomical descriptions of the living human brain.

Adult↗

PubMed2002

Proton magnetic resonance spectroscopy reveals similar white matter biochemical changes in patients with chronic hypertension and early Alzheimer's disease.

OBJECTIVES: Hypertension is a risk factor for dementia and is associated with some of the brain changes that are found in Alzheimer's disease and other neurodegenerative diseases, such as atrophy and neurofibrillary tangles. We evaluated the cerebral white matter biochemical pattern in healthy older subjects, older patients with chronic hypertension, and patients with Alzheimer's disease (AD) using proton magnetic resonance spectroscopy (1H-MRS). DESIGN: Cross-sectional study. SETTING: University-affiliated outpatient clinic. PARTICIPANTS: Ten healthy older subjects, 10 cognitively intact older patients with chronic hypertension, and 10 older patients with early AD. MEASUREMENTS: All subjects underwent clinical examination, neuropsychological assessment, and 1H-MRS to measure N-acetylaspartate (NAA), myoinositol, choline, and creatine resonance signals in an 8-cm3 voxel located in the paratrigonal white matter region bilaterally. NAA/creatine, myoinositol/creatine, and choline/creatine ratios were measured, and the mean values were compared using one-way analysis of variance with Tukey test for post hoc analysis. RESULTS: A significantly higher mean myoinositol/creatine (ratio +/- standard deviation) was found in hypertensive patients (0.67 +/- 0.05) and in AD patients (0.68 +/- 0.08) than in controls (0.56 +/- 0.04) (P <.001). Conversely neither NAA/creatine ratio nor choline/creatine ratio differed among the three groups. CONCLUSIONS: In this study, cognitively intact chronic hypertensive older patients had a higher white matter myoinositol/creatine ratio compared with healthy older subjects, suggesting that myoinositol may be a sensitive marker of the effects of chronic hypertension on the brain. Moreover, the similar increase of myoinositol/creatine ratio in patients with hypertension and in those with early AD provides further evidence of common brain changes with these conditions.

Aged↗

PubMed2002

Spatial normalization and averaging of diffusion tensor MRI data sets.

Diffusion tensor magnetic resonance imaging (DT-MRI) is unique in providing information about both the structural integrity and the orientation of white matter fibers in vivo and, through "tractography", revealing the trajectories of white matter tracts. DT-MRI is therefore a promising technique for detecting differences in white matter architecture between different subject populations. However, while studies involving analyses of group averages of scalar quantities derived from DT-MRI data have been performed, as yet there have been no similar studies involving the whole tensor. Here we present the first step towards realizing such a study, i.e., the spatial normalization of whole tensor data sets. The approach is illustrated by spatial normalization of 10 DT-MRI data sets to a standard anatomical template. Both qualitative and quantitative approaches are described for assessing the results of spatial normalization. Techniques are then described for combining the spatially normalized data sets according to three definitions of average, i.e., the mean, median, and mode of a distribution of tensors. The current absence of, and hence need for, appropriate statistical tests for comparison of results derived from group-averaged DT-MRI data sets is then discussed. Finally, the feasibility of performing tractography on the group-averaged DT-MRI data set is investigated and the possibility and implications of generating a generic map of brain connectivity from a group of subjects is considered.

Adult↗

PubMedDate not supplied

[Treatment of esophageal perforations. Considerations on a clinical case].

The Authors describe a rare case of esophageal perforation occurred after Transoesophageal echocardiography in 68 years old patient and review the literature relating to the causes and management of this pathology. Transoesophageal echocardiography, which is a semi-invasive investigation increasingly used in cardiology and cardiac surgery and intensive care units, is a rare though extremely dangerous cause of such complications. Perforation of the esophagus continues to present a formidable diagnostic and therapeutic challenge. The diagnosis depends on a high degree of suspicion and on the recognition of clinical features and is confirmed by contrast esophagography. The outcome after esophageal perforation depends on the location of the injury, the presence or otherwise of concomitant esophageal disease and the time elapsing between the injury and inititian of treatment. Reinforced primary repair of the perforation is the procedure most frequently employed and preferred for the surgical management of the esophageal perforation. In the case reported here, early diagnosis and prompt surgical treatment consisting in primary repair of the esophageal perforation contributed to the successful management of this serious pathology.

Aged↗