Biomedical subjects

Roberto B Sassi

Publications and source records attributed to Roberto B Sassi.

24 records · Page 2Linked to original sources

PubMed2003

Anatomical MRI study of basal ganglia in major depressive disorder.

The basal ganglia form a part of the brain neuroanatomic circuits that may be involved in mood regulation. Decreases in basal ganglia volumes have been previously reported in major depressive disorder patients in comparison to healthy controls. In this study, we measured caudate, putamen, and globus pallidus volumes in 25 patients with major depressive disorder (4 M; age+/-S.D.=41+/-11 years) and 48 healthy controls (29 M; age+/-S.D.=35+/-10 years), using high-resolution magnetic resonance imaging (MRI), in an attempt to replicate prior findings. Unlike most previous studies, we did not find significant differences between patient and control groups in basal ganglia volumetric measures. Nonetheless, there was a significant interaction between diagnosis and cerebral hemisphere, with MDD patients showing decreased asymmetry in globus pallidus volumes in comparison with healthy controls. Furthermore, in the patient group, left putamen volumes correlated inversely with length of illness, and left globus pallidus volume correlated directly with number of prior depressive episodes. These findings suggest that abnormalities in lateralization and possibly neurodegenerative changes in basal ganglia structures participate in the pathophysiology of major depressive disorder.

Adolescent↗

PubMed2003

White matter hyperintensities in bipolar and unipolar patients with relatively mild-to-moderate illness severity.

BACKGROUND: Increased rates of white matter hyperintense lesions have been reported in mood disorder patients. However, the potential effects of age and illness severity on reported findings are not fully established. We examined the rates of hyperintense lesions in adult, non-elderly bipolar and unipolar patients, with a relatively mild-to-moderate illness severity, and in matched healthy controls. METHOD: We examined brain MRI images in 24 bipolar (19-56 years, mean+/-S.D.=34.2+/-9.9 years) and 17 unipolar patients (24-59 years, 42.8+/-9.2 years), and 38 healthy controls (21-59 years, 36.8+/-9.7 years). T2-weighted and proton-density axial MRI images were obtained at 1.5 Tesla. The lesions were rated by two independent raters, using a semi-quantitative rating scale. RESULTS: There were no significant differences in the frequency of hyperintensities between bipolar or unipolar patients and healthy controls. Age was related to the presence of subcortical gray matter hyperintensities for the whole sample. Among the unipolar patients, length of illness and presence of mood disorder in a first-degree relative were related to deep and periventricular white matter lesions, respectively. LIMITATIONS: The methodology utilized for measurement of the white matter hyperintensities was semi-quantitative. CONCLUSIONS: Increased rates of white matter hyperintensities do not appear to be present in a group of relatively young mood disorder patients, with relatively mild to moderate illness severity. These brain lesions may be more directly related to late-life and more severe cases of these illnesses.

Adult↗

PubMed2002

Increased gray matter volume in lithium-treated bipolar disorder patients.

Lithium's neurotrophic effects have been reported in several in vitro and ex vivo studies. Preliminary human studies with magnetic resonance imaging (MRI) and spectroscopy have recently provided evidence of lithium-induced increases in gray matter volumes and N-acetyl-aspartate levels. In order to further examine the hypothesis that lithium treatment would relate to detectable increases in gray matter brain content, we blindly measured gray and white matter volumes in MRI images of 12 untreated and 17 lithium-treated bipolar patients and 46 healthy controls. Using multivariate analysis of covariance with age and gender as covariates, we found that total gray matter volumes were significantly increased in lithium-treated (747.9 +/- 69.8 cm(3)) compared with untreated patients (639.2 +/- 91.2 cm(3); F = 10.6; d.f. = 1, 25; P = 0.003) and healthy individuals (675.8 +/- 61.8 cm(3); F = 17.4; d.f. = 1, 59; P < 0.001), suggesting in vivo effects of lithium on gray matter, which could possibly reflect lithium's neurotrophic effects.

Analysis of Variance↗

PubMed2002

Anatomical MRI study of subgenual prefrontal cortex in bipolar and unipolar subjects.

This study attempted to replicate previous findings of decreased gray matter content in the subgenual prefrontal cortex (SGPFC) in mood disorder patients. Eighteen DSM-IV unipolar patients, 27 DSM-IV bipolar patients, and 38 healthy controls were studied. A 1.5T GE Signa Imaging System with Signa 5.4.3 software was used. The semi-automated software MedX (Sensor Systems, Sterling, VA) was utilized for the anatomical measures of SGPFC volumes. There were no significant differences in SGPFC volumes in familial and non-familial unipolar and bipolar patients compared with healthy controls, nor between drug-free and lithium-treated bipolar patients (ANOVA, p >.05). In vivo abnormalities in the volumes of SGPFC were not identified in mildly depressed or euthymic unipolar or bipolar mood disorder outpatients, either familial or non-familial.

Adult↗

PubMed2001

Emerging therapeutic targets in bipolar mood disorder.

Bipolar mood disorder is a chronic, severe and life-threatening psychiatric illness, whose underlying pathophysiology is still obscure. Lithium is the mainstay of treatment for this illness, with robust acute antimanic and long-term prophylactic effects. Over the past decade, valproate has been another medication shown to have possibly similar mood-stabilising properties to lithium, in double-blind controlled trials. Nonetheless, among patients suffering from bipolar disorder, a substantial percentage appears to respond poorly to currently available pharmacological therapies, including lithium, valproate, carbamazepine and other newer compounds, clearly demonstrating that there is a substantial need for improved therapeutic agents. Very significant effort has been made in the past several years to elucidate the cellular mechanisms by which lithium and valproate produce their therapeutic effects. The available evidence points to a modulatory action of these compounds over multiple neural biochemical pathways and most investigations have found relevant actions of mood stabilisers on intracellular signal transduction mechanisms. Moreover, it has been shown in recent years that lithium and valproate lead to long-term changes in neural plasticity, with eventual neurotrophic and neuroprotective effects. Although these actions are not fully understood, stimulation of transcription factors and effects on gene expression are potentially involved. The search for the mechanisms of action of well-established mood-stabilisers has helped to reveal promising molecular targets to test novel therapeutic approaches. This review will examine the current investigations on the diverse biochemical and molecular pathways regulated by either lithium or valproate and highlight the potential cellular targets for the development of novel mood stabilisers.

Journal Article↗

PubMedDate not supplied

MRI investigation of temporal lobe structures in bipolar patients.

Previous anatomical MRI studies have suggested abnormalities in amygdala volumes in bipolar disorder, whereas hippocampus, temporal lobe (TL), and superior temporal gyri (STG) measures have been reported to be normal. This study further investigated the existence of anatomical abnormalities in these brain structures in bipolar subjects, to attempt to replicate previously reported findings. Twenty-four DSM-IV bipolar patients (mean age+/-S.D.=35+/-10 years) and 36 healthy controls (mean age+/-S.D.=37+/-10 years) were studied. 3D SPGR images were obtained with a 1.5T-GE Signa magnet (TR=25 ms, TE=5 ms, FOV=24 cm, slice-thickness=1.5 mm, matrix-size=256 x 192). Volumetric measurements of TL, hippocampus, amygdala, and STG were performed blindly, with a semi-automated software. Bipolar patients had significantly larger left amygdala volumes compared with controls (mean volumes+/-S.D.=2.57+/-0.69 vs. 2.17+/-0.58 ml, respectively; ANCOVA, age, gender, ICV as covariates; F=4.42, df=1/55, P=0.04). The volumes of the other temporal lobe structures did not differ significantly between the two groups (ANCOVA, age, gender, and ICV as covariates, P>0.05). Our findings of enlarged left amygdala in bipolar patients are in agreement with prior MRI studies, suggesting that abnormalities in this brain structure may be implicated in pathophysiology of the illness. Longitudinal studies in high-risk offspring and first-episode patients will be needed to examine whether such abnormalities precede the appearance of symptoms, or whether they may appear subsequently as a result of illness course.

Adult↗