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Biomedical subjects

S Bonavita

Publications and source records attributed to S Bonavita.

18 recordsLinked to original sources
PubMed2003

GABA(B) receptor 1 polymorphism (G1465A) is associated with temporal lobe epilepsy.

BACKGROUND: Dysfunction of gamma-aminobutyric acid (GABA) (B) receptors has been implicated in the pathogenesis of temporal lobe epilepsy (TLE). OBJECTIVE: To evaluate the genetic contribution of cloned human GABA(B) receptors to TLE. METHODS: The authors genotyped 141 patients (78 women and 63 men; mean age = 49.1 +/- 18.0 years) with nonlesional TLE and 372 age- and sex-matched normal individuals for the known polymorphism G1465A in the human GABA(B) receptor 1 [GABA(B[1])] gene. RESULTS: There was a highly significant overrepresentation of the G1465A heterozygote in patients with TLE compared with controls. The A/G genotype was found in 17% of the 141 patients with TLE and in only 0.5% of the 372 controls (p < 0.0001). The authors also found that patients carrying the A allele had a significantly higher risk (p = 0.003, OR = 6.47, 95% CI = 2.02 to 20.76) of developing drug-resistant TLE. Furthermore, the age at onset of seizures tended to be lower in patients with A/G genotype, but the difference was not significant. CONCLUSIONS: The results of this study indicate that the GABA(B[1]) polymorphism (G1465A) confers a highly increased susceptibility to TLE. Moreover, it seems to influence the severity of this common epileptic disorder.

Age of Onset↗
PubMed2002

Genetic association of alpha2-macroglobulin polymorphisms with AD in southern Italy.

The authors investigated the segregation of two polymorphisms of the alpha2-macroglobulin gene (A2M-I/D and A2M-Ile1000Val) in patients with sporadic AD from southern Italy. The A2M-I and A2M-Val1000 alleles were more frequent in cases than in controls, and this effect was independent from the APOE-epsilon4 status as well as from the age at onset of AD. Moreover, subjects carrying the A2M genotype I/I-Val/Val had a threefold increase of risk for AD. These data support a population-based susceptibility for AD linked to A2M polymorphisms.

Aged↗
PubMed2002

Proton MR spectroscopic imaging in multiple sclerosis.

We studied 24 patients with multiple sclerosis (MS) by proton magnetic resonance spectroscopic imaging (1H-MRSI) to assess the neurochemical pathology of the white-matter lesions (WML) and normal-appearing white matter (NAWM). Our 1H-MRSI technique allowed simultaneous measurement of N-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine plus phosphocreatine (Cr) signal intensities from four 15-mm slices divided into 0.84 ml single-volume elements. In WML we found significantly lower NAA/Cr and NAA/Cho ratios and a significantly higher Cho/Cr ratio than in NAWM or control white matter. In NAWM, NAA/Cr and Cho/Cr were significantly lower than in control white matter. 1H-MRSI was compatible with damage to myelin in WML, and with axonal damage and/or dysfunction in WML and NAWM. These findings extend data on involvement of NAWM in MS beyond the abnormalities visible on MRI.

Adult↗
PubMed2002

Anti-GM1 ganglioside antibodies in Parkinson's disease.

OBJECTIVES: To determine whether anti-GM1 antibodies are increased in Parkinson's disease (PD). METHODS: Serum immunoglobulin M (IgM) and IgG anti-GM1 antibodies were detected by enzyme-linked immunosorbent assay (ELISA) in 147 patients with PD and in 186 age-matched normal control subjects. Sera were assayed at initial dilution of 1:800 for IgM and 1:200 for IgG and were considered positive at absorbance values exceeding the value of 0.05 for IgM and 0.1 for IgG. RESULTS: Forty patients with PD (27.2%) had sera positive for IgM anti-GM1 antibodies, whereas only five normal controls (2.7%) resulted positive (P < 0.0001). Most of patients (75%) with positive sera had a tremor-dominant form of PD. Only two patients with PD (1.4%) and none of normal controls had sera positive for IgG anti-GM1 antibodies. CONCLUSION: A consistent portion of parkinsonians, mainly with a tremor-dominant form of PD, may have increased circulating IgM anti-GM1 antibodies.

Aged↗
PubMed2001

Evidence for neuroaxonal injury in patients with proteolipid protein gene mutations.

The authors used proton MRS to investigate neuropathologic correlates in nine patients with proteolipid protein (PLP) gene mutations who did not show cerebral atrophy on cranial MRI. When compared with 16 age-matched control participants, patients with PLP mutations had significant and widespread decreased brain N-acetyl aspartate, a neuronal marker. The authors conclude that PLP mutations cause neuroaxonal injury, which in turn contributes to the neurologic deficit observed in these patients.

Adolescent↗
PubMed2000

Spectroscopic imaging of radiation-induced effects in the white matter of glioma patients.

External radiation therapy of brain tumors may cause adverse effects on normal brain tissue, resulting in severe neuropsychological and cognitive impairment. We investigated the late delayed radiation effects in the white matter (WM) using (1)H magnetic resonance spectroscopic imaging ((1)HMRSI). Nine glioma patients with local radiation-induced signal abnormalities in the T(2)-weighted MR images were studied with nine age- and sex-matched controls. The metabolite ratios in the radiation-induced hyper intensity area (RIHA) and in the normal appearing white matter (NAWM) of the patients were compared with respective WM areas of the controls. In RIHA, choline/creatine (Cho/Cr) was 17% decreased (1.22 +/- 0.13 vs 1.47 +/- 0.16, p = 0.0027, significant (s), unpaired Student's t test with Bonferroni correction) in the patients compared to the controls, while there was no difference in N-acetyl aspartate/Cr (NAA/Cr) (2.49 +/- 0.57 vs 2.98 +/- 0.32, p = 0.039) or NAA/Cho (2. 03 +/- 0.40 vs 2.04 +/- 0.17, p = 0.95). In NAWM, Cho/Cr was 24% decreased (1.21 +/- 0.15 vs 1.59 +/- 0.13, p < 0.0001, s) and NAA/Cho was 20% increased (2.49 +/- 0.49 vs 1.98 +/- 0.15, p = 0. 0082, s) in the patients compared to the controls, while there was no difference in NAA/Cr (2.99 +/- 0.46 vs 3.16 +/- 0.32, p = 0.38). NAA(RIHA)/NAA(NAWM) was 25% decreased (0.75 +/- 0.20 vs 1.00 +/- 0. 12, p = 0.0043, s) and Cr(RIHA)/Cr(NAWM) was 16% decreased (0.89 +/- 0.15 vs 1.06 +/- 0.10, p = 0.013, s) in the patients compared to the controls, while there was no difference in Cho(RIHA)/Cho(NAWM) (0.92 +/- 0.23 vs 0.98 +/- 0.10, p = 0.47). (1)HMRSI reveals widespread chemical changes in the WM after radiation therapy. In RIHA, there is loss of NAA, Cho, and Cr implying axonal and membrane damage and in NAWM, there is loss of Cho, reflecting membrane damage.

Adult↗
PubMed1999

Diffuse central neuronal involvement in Fabry disease: a proton MRS imaging study.

BACKGROUND: The in vivo determination of parenchymal involvement is important to evaluate disease burden. Proton MRS imaging (1H-MRSI) permits simultaneous measurement of N-acetylaspartate (NA), a putative neuron-specific molecule, choline-containing compounds, creatine-phosphocreatine, and lactate from four 15-mm slices divided into 0.84-mL single-volume elements. OBJECTIVE: To assess the cortical and subcortical neuropathology in Fabry disease (FD). METHODS: Regions of interest (ROIs) were selected from several cortical and subcortical locations in nine FD patients. Mean ROI metabolite ratios were compared with control values. RESULTS: FD patients showed a widespread pattern of cortical and subcortical NA reduction. Seven patients showed discrete MRI abnormalities consisting of white matter hyperintensities or basal ganglia infarcts. CONCLUSION: We found diffuse neuronal involvement in FD extending beyond the areas of MRI-visible cerebrovascular abnormalities. 1H-MRSI may become useful in therapeutic trials.

Adult↗
PubMed1999

MR image segmentation and tissue metabolite contrast in 1H spectroscopic imaging of normal and aging brain.

The impact of image segmentation on 0.84-ml nominal voxel volume proton spectroscopic imaging in normal brain and in age-related cortical atrophy was investigated. Segmentation improved the gray matter-white matter (GM-WM) contrast for N-acetyl aspartate (NAA)/creatine (Cr) and choline (Cho)/Cr in normal brain, and for NAA/Cho and NAA/Cr in atrophic brain. NAA(GM/WM) (approximately 0.7), Cho(GM/WM) (approximately 0.8), and Cr(GM/WM) (approximately 1.3) in normal brain obtained with segmentation agreed with values obtained with quantitative magnetic resonance spectroscopy. Age-related cortical atrophy led to decreased cortical GM NAA/Cho and NAA/Cr; no changes were evident in WM or in NAA(GM/WM), Cho(GM/WM), or Cr(GM/WM). GM/WM metabolite analysis may be of limited use in conditions in which parallel metabolite changes occur in WM and GM.

Adult↗
PubMed1999

Exploring brain function with magnetic resonance imaging.

Since its invention in the early 1990s, functional magnetic resonance imaging (fMRI) has rapidly assumed a leading role among the techniques used to localize brain activity. The spatial and temporal resolution provided by state-of-the-art MR technology and its non-invasive character, which allows multiple studies of the same subject, are some of the main advantages of fMRI over the other functional neuroimaging modalities that are based on changes in blood flow and cortical metabolism. This paper describes the basic principles and methodology of fMRI and some aspects of its application to functional activation studies. Attention is focused on the physiology of the blood oxygenation level-dependent (BOLD) contrast mechanism and on the acquisition of functional time-series with echo planar imaging (EPI). We also provide an introduction to the current strategies for the correction of signal artefacts and other image processing techniques. In order to convey an idea of the numerous applications of fMRI, we will review some of the recent results in the fields of cognitive and sensorimotor psychology and physiology.

Artifacts↗
PubMed1999

Proton MRS in neurological disorders.

Proton magnetic resonance spectroscopy (1H MRS) permits the acquisition of the signal arising from several brain metabolites. At long echo-time (TE) 1H MRS can detect N-acetyl-aspartate containing compounds, choline containing compounds, creatine + phosphocreatine and lactate. At short TE, lipids, tryglicerides, alanine, glutamate, glutamine, GABA, scyllo-inositol, glucose, myo-inositol, carnosine and histydine are visible. 1H MRS can be performed with single-voxel, multivoxel, single slice and multislice techniques. With single voxel 1H MRS it is possible to measure metabolites relaxation time, which allows the measurement of metabolite concentrations. This technique can be useful in the study of focal lesions in the central nervous system (CNS) such as epilepsy (pre-surgical identification of epileptic focus), brain tumors (evaluation of recurrence and radiation necrosis), stroke, multiple sclerosis, etc. Single slice and multislice 1H MRS imaging (1H MRSI) can be performed only at long TE and permits the mapping of the brain metabolites distribution which makes them particularly useful in studying diffuse diseases and heterogeneous lesions of the CNS. 1H MRS can also be useful in the evaluation of 'ischemic penumbra' of stroke; developmental (myelin and neuronal dysgenesis); head trauma (evaluation of cerebral damage not visible with MRI); degenerative disorders (identification of microscopic pathology not visible with MRI); and metabolic diseases (metabolic disturbances with specific metabolic patterns).

Brain↗
PubMed1998

Proton magnetic resonance spectroscopic imaging in the clinical evaluation of patients with Niemann-Pick type C disease.

OBJECTIVES: 10 patients with Niemann-Pick disease type C (NP-C) were studied by proton magnetic resonance spectroscopic imaging (1H-MRSI) to assess the biochemical pathology of the brain and to determine whether this method can be useful to clinically evaluate these patients. METHODS: 1H-MRSI permits the simultaneous measurement of N-acetyl aspartate (NA), compounds containing choline (Cho), creatine plus phosphocreatine (Cre), and lactate (Lac) signal intensities from four 15 mm slices divided into 0.84 ml single volume elements. Spectroscopic voxels were identified from seven regions of interest. RESULTS: In patients with NP-C, NA/Cre was significantly decreased in the frontal and parietal cortices, centrum semiovale, and caudate nucleus; Cho/Cre was significantly increased in the frontal cortex and centrum semiovale. Significant correlations were found between clinical staging scale scores and 1H-MRSI abnormalities. CONCLUSION: 1H-MRSI showed diffuse brain involvement in patients with NP-C consistent with the pathological features of the disease. 1H-MRSI is an objective and sensitive tool to neurologically evaluate patients with NP-C.

Adolescent↗
PubMed1997

White matter lesion detection in multiple sclerosis: improved interobserver concordance with multispectral MRI display.

An assessment of the detectability of white matter lesions and of concordance between observers with different levels of MRI reading experience was performed with comparative evaluation of spin-echo MRI images and of corresponding "multispectral" maps in 16 patients with definite multiple sclerosis (MS). Multispectral maps were obtained by means of a recently described post-processing technique based on the simultaneous display of MRI parameters and a standardized colour scale with red, green and blue coding for relaxation rates R1 and R2 and proton density, respectively. Spin-echo images on films and multispectral maps displayed on a personal computer were randomly rated at 2-month intervals. Interobserver concordance (k-test) was assessed among three readers with different levels of MRI experience (an experienced neuroradiologist, a radiology resident and a neurologist). For multispectral maps we found increased interobserver concordance with the experienced neuroradiologist (multispectral vs conventional images; k = 0.77 vs 0.66 for the radiology resident and 0.66 vs 0.56 for the neurologist), an increased number of detected lesions and decreased reading time. Multispectral maps permit easy detection of MS lesions and may improve interobserver concordance compared with conventional spinecho studies.

Adult↗
PubMed1997

Proton magnetic resonance spectroscopic imaging in progressive supranuclear palsy, Parkinson's disease and corticobasal degeneration.

We used proton magnetic resonance spectroscopic imaging (1H-MRSI) to assess the in vivo cortical and subcortical neuronal involvement in progressive supranuclear palsy, Parkinson's disease and corticobasal degeneration. This technique permitted the simultaneous measurement of compounds containing N-acetylaspartate (NA), choline (Cho), creatine-phosphocreatine (Cre) and lactate, from four 15-mm slices divided into 0.84-ml single-volume elements. The study included 12 patients with progressive supranuclear palsy, 10 with Parkinson's disease, nine with corticobasal degeneration and 11 age-matched normal control subjects. Regions of interest were selected from the brainstem, caudate, thalamus, lentiform nucleus, centrum semiovale, and from frontal, parietal, precentral, temporal and occipital cortices. Progressive supranuclear palsy patients, compared with control subjects, had significantly reduced NA/Cre in the brainstem, centrum semiovale, frontal and precentral cortex, and significantly reduced NA/Cho in the lentiform nucleus. Corticobasal degeneration patients, compared with control subjects, had significantly reduced NA/Cre in the centrum semiovale, and significantly reduced NA/Cho in the lentiform nucleus and parietal cortex. There were no significant differences between Parkinson's disease patients and control subjects, or between patients groups in any individual region of interest. In the parietal cortex of corticobasal degeneration patients, NA/Cho was significantly reduced contralateral to the most affected side. There were statistically significant group differences in the regional pattern of NA/Cre and NA/Cho reduction, comparing normal control subjects with all patient groups, Parkinson's disease with corticobasal degeneration, and Parkinson's disease with progressive supranuclear palsy. Although the occurrence of significant groups differences does not imply that it is possible to differentiate between individual patients using 1H-MRSI in progressive supranuclear palsy and corticobasal degeneration, detection of specific cortical and subcortical patterns of neuronal involvement is possible with this technique. We suggest that this regional pattern of neuronal involvement found in progressive supranuclear palsy and corticobasal degeneration may help in the diagnostic evaluation of affected individuals.

Aged↗
PubMed1997

Increased choline signal coinciding with malignant degeneration of cerebral gliomas: a serial proton magnetic resonance spectroscopy imaging study.

The authors tested the hypothesis that proton magnetic resonance spectroscopy (1H-MRS) imaging can be used as a supportive diagnostic tool to differentiate clinically stable brain tumors from those progressing as a result of low- to high-grade malignant transformation or posttherapeutic recurrence. Twenty-seven patients with cerebral gliomas verified on histological examination were studied repeatedly with 1H-MRS imaging over a period of 3.5 years. At the time of each 1H-MRS imaging study, clinical examination, MR imaging, positron emission tomography with 18F-fluorodeoxyglucose, and biopsy findings (when available) were used to categorize each patient as having either stable or progressive disease. Measures of the percentage changes in the choline (Cho) 1H-MRS imaging signal intensity between studies, which were obtained without knowledge of the clinical categorization, allowed the investigators to segregate the groups with a high degree of statistical significance. All progressive cases showed a Cho signal increase between studies of more than 45%, whereas all stable cases showed an elevation of less than 35%, no change, or even a decreased signal. The authors conclude that increased Cho levels coincide with malignant degeneration of cerebral gliomas and therefore may possibly be used as a supportive indicator of progression of these neoplasms.

Adult↗
PubMed1996

Proton magnetic resonance spectroscopic imaging in patients with cerebellar degeneration.

Using proton magnetic resonance spectroscopic imaging, we studied the cerebellum of 9 patients with cerebellar degeneration and of 9 age-matched normal control subjects. This technique permits the simultaneous measurement of N-acetylaspartate, choline-containing compounds, creatine/phosphocreatine, and lactate signal intensities from four 15-mm slices divided into 0.84-ml single-volume elements. Because patients with cerebellar degeneration often show substantial atrophy on magnetic resonance imaging (MRI), we specifically chose to analyze the spectroscopic signals only from tissue that did not have an atrophic appearance on the MRI. The spectroscopic findings showed a significant reduction of N-acetylaspartate in all parts of the cerebellum, a significant correlation with MRI scores of cerebellar atrophy, and a significant correlation with clinical rating scores of cerebellar disturbance. Our method of analysis suggests the presence of a neurodegenerative process in cerebellar areas that do not appear to be atrophic on the MRI. Some limitations of proton magnetic resonance spectroscopic imaging in the present study were related to the partial field inhomogeneity characteristics of the posterior fossa, the anatomical location of the cerebellum, and the particularly severe cerebellar atrophy in some of the patients.

Adult↗
PubMed1996

Cortical and subcortical chemical pathology in Alzheimer's disease as assessed by multislice proton magnetic resonance spectroscopic imaging.

BACKGROUND: Multislide proton magnetic resonance spectroscopic imaging (1H-MRSI) permits the simultaneous acquisition of N-acetylaspartate (NA), choline (Cho), creatine/phosphocreatine (Cre), and lactate (Lac) signal intensities from four 15-mm slices divided into 0.84-ml single-volume elements. NA is inferred to be a neuron-specific molecule, whereas Cho mainly reflects glycerophosphocholine and phosphocholine, compounds involved in phospholipid metabolism. OBJECTIVE: To assess whether 1H-MRSI could detect a regional pattern of cortical and subcortical involvement in the brain of Alzheimer's disease (AD) patients. METHODS: 1H-MRSI was performed in 15 patients with probable AD and 15 age-matched healthy controls. Regions of interest (ROIs) were selected from frontal (FC), temporal (TC), parietal (PC), occipital, and insular cortices, subcortical white matter (WM), and thalamus. RESULTS: In AD patients, we found a significant reduction of NA/Cre in the FC, TC, and PC and a significant reduction of Cho/Cre in the WM. CONCLUSIONS: This 1H-MRSI study of AD patients shows a regional pattern of neuronal damage in the associative cortices, as revealed by significant reduction of NA/Cre in the FC, TC, and PC, and regional derangement of phospholipid metabolism, as revealed by significant reduction of Cho/Cre in the WM.

Aged↗