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Biomedical subjects

A C Bastos

Publications and source records attributed to A C Bastos.

13 recordsLinked to original sources
PubMed2004

Cortical malformations are associated with a rare polymorphism of cellular prion protein.

Studies in animals lacking the cellular prion protein (PrP(c)) gene (Prnp) showed higher neuronal excitability in vitro and increased sensitivity to seizures in vivo. The authors previously reported a rare polymorphism at codon 171 (Asn-->Ser) of human Prnp to be associated with mesial temporal lobe epilepsy related to hippocampal sclerosis. They demonstrated that the same variant allele is also associated with symptomatic epilepsies related to different forms of malformations of cortical development.

Adolescent↗
PubMed2004

Posterior cingulate metabolic changes occur in Parkinson's disease patients without dementia.

The basis for cognitive deficits in Parkinson's disease (PD) is unknown. Hippocampal atrophy has been shown in Alzheimer's disease (AD) and PD. N-Acetyl aspartate (NAA)/creatine (Cr) ratio in the posterior cingulate gyrus (PCG) is decreased in AD, but unknown in PD. Volumetric magnetic resonance (MR) imaging (at 1.5 T) determined corrected HC volume and MR spectroscopy (MRS) PCG metabolites in 12 non-demented mild to moderately affected PD patients (six male, six female) and ten controls (five male, five female). Age (PD=60.6 years, control=62.2; P=0.62), education (PD=14.1 years, controls=13.8; P=0.89) and global cognition (Mini-Mental State Exam score: PD=28.7, controls=29.6; P=0.14) did not differ. Only recall (CVLT-II, P=0.046) and NAA/Cr (PD=1.53, controls=1.78; P=0.03) were decreased in PD. Memory correlated with NAA/Cr (r=0.65, P=0.02) in PD. In conclusion, cingulate metabolic changes occur in PD.

Aged↗
PubMed2001

Typical and atypical perfusion patterns in periictal SPECT of patients with unilateral temporal lobe epilepsy.

PURPOSE: To characterize perfusion patterns of periictal single-photon emission tomography (SPECT) in patients with unilateral temporal lobe epilepsy (TLE) and to determine their relationship to the epileptogenic zone (EZ). METHODS: We studied periictal SPECT scans of 53 patients after anterior mesial temporal lobectomy who had good seizure outcome after surgery. Ictal SPECT scans were performed during video-EEG monitoring. Typical SPECT patterns consisted of ipsilateral ictal hyperperfusion or ipsilateral postictal hypoperfusion. Atypical ictal patterns included normal scans, bilateral temporal hyperperfusion, or contralateral patterns. These perfusion patterns were retrospectively analyzed searching for concordance rate with the EZ. RESULTS: We obtained 51 ictal and two early postictal scans. In the typical group, 40 (75.4%) patients had ipsilateral ictal temporal lobe hyperperfusion, and one (1.9%) patient had ipsilateral postictal temporal lobe hypoperfusion. Twelve (22.7%) patients exhibited atypical perfusion patterns: seven (13.2%) patients had bitemporal ictal hyperperfusion (four cases showed asymmetric temporal lobe changes), four (7.6%) patients had contralateral hyperperfusion, and one (1.9%) patient had a normal SPECT scan. All four patients with bitemporal asymmetric hyperperfusions showed greater perfusion lateralized to the side of the EZ. Three of the four patients who had contralateral hyperperfusion also had a complex postictal-like pattern in the ipsilateral temporal lobe consisting of anteromesial hyperperfusion with adjacent lateral hypoperfusion. CONCLUSIONS: This study analyzed typical and atypical perfusion patterns in unilateral TLE, and suggested that not only typical, but also some atypical perfusion patterns may contribute to the lateralization of EZ.

Adolescent↗
PubMed2001

Role of Tamm-Horsfall protein in the binding and in vivo phagocytosis of type 1 fimbriated Escherichia coli by mouse peritoneal macrophages.

Tamm-Horsfall glycoprotein (THP) contains manno-oligosaccharides that are recognized by type 1 fimbriae (F1) of Escherichia coli. In the present study, we examined the in vivo phagocytic activity of mouse peritoneal macrophages after treatment of bacteria with THP. At low THP concentrations (12.5 microg/ml and 50 microg/ml) no significant difference was observed in the phagocytosis of E. coli F1+. However, at high THP concentrations (500 microg/ml and 1250 microg/ml) we obtained a reduction of bacterial phagocytosis by mouse peritoneal macrophages.

Adjuvants, Immunologic↗
PubMed2000

Familial perisylvian polymicrogyria: a new familial syndrome of cortical maldevelopment.

Two familial X-linked dominant syndromes of cortical maldevelopment have recently been described: double cortex/lissencephaly syndrome and bilateral periventricular nodular heterotopia. We report on 12 kindreds with familial perisylvian polymicrogyria (FPP) presenting at 10 centers, examine the clinical presentation in these familial cases, and propose a possible mode of inheritance. The clinical and radiological pattern was variable among the 42 patients, with clinical differences among the families and even within members of the same family. Pseudobulbar signs, cognitive deficits, epilepsy, and perisylvian abnormalities on imaging studies were not found in all patients. When present, they displayed a spectrum of severity. The only clear correlation in this study was between bilateral imaging findings and abnormal tongue movements and/or pronounced dysarthria. Most of the families provided evidence suggestive of, or compatible with, X-linked transmission. On the other hand, the pedigrees of 2 families ruled out X-linked inheritance. The most likely mode of inheritance for these 2 families was autosomal dominant with decreased penetrance; however, autosomal recessive inheritance with pseudodominance could not be ruled out in 1 family. We conclude that FPP appears to be genetically heterogeneous. However, most of the families probably represent a third previously undescribed X-linked syndrome of cortical maldevelopment.

Adolescent↗
PubMed1999

Diagnosis of subtle focal dysplastic lesions: curvilinear reformatting from three-dimensional magnetic resonance imaging.

Focal cortical dysplasia is a frequent cause of medically intractable partial epilepsy. These lesions are being increasingly identified by high quality images provided by magnetic resonance imaging (MRI), resulting in improved seizure control of surgically treated patients. Small dysplastic lesions are often missed by conventional MRI methods. The identification of subtle structural abnormalities by rectilinear slices is often limited by the complex convolutional pattern of the brain. We developed a method of curvilinear reformatting of three-dimensional MRI data that improves the anatomical display of the gyral structure of the hemispheric convexities. It also reduces the asymmetric sampling of gray-white matter that may lead to false-positive results. We present 5 patients in whom conventional two-dimensional and three-dimensional MRI with multiplanar reformatting was initially considered normal. Subsequent studies using curvilinear reformatting identified lesions in all. Four patients underwent surgery with histological diagnosis of focal cortical dysplasia. Three patients are seizure-free and 1 had significant improvement in seizure control. These results indicate that an increase in the detection of subtle focal dysplastic lesions may be accomplished when one improves the anatomical display of the brain gyral structure by performing curvilinear reformatting.

Adolescent↗
PubMed1998

Topographic analysis of the gyral patterns of the central area.

Great advances in imaging technology allows the surgeon to visualize the entire brain surface during surgery. However, the cerebral convolutions are extremely complex, so that it is often difficult to define the central area precisely. Using the curvilinear reconstruction technique (Gyroview) and MRI, we have analyzed the gyral anatomy of the central area in 20 normal brans and have recognized several patterns of topographic organization and have classified them into several categories. We divided the central area into anterior and posterior subregions with the central sulcus as the main landmark. More specifically, we studied how the pre- and postcentral gyri merge into the frontal and parietal lobe proper by anatomical bridges (roots). We describe three anterior and two main posterior roots which originate from the precentral and the postcentral gyrus, respectively. We found four different types of pattern for the anterior roots and as many as 10 different patterns for the posterior roots. The arterior roots are relatively constant, compared to the posterior ones. The most frequent pattern (type 1) was found in 33 hemispheres among the 40 analyzed (82.5%). Four main posterior root patterns were recognized in 32 hemispheres of the 40 analyzed (80%). Thus, although gyral variability was encountered for the posterior roots, a very constant global pattern was seen for the central area. One of the most important steps of frameless stereotactic-guided epilepsy surgery is the precise localization of the central area. Therefore, a knowledge of gyral patterns of the central area is essential not only for the resective epilepsy surgery, but also for the successful removal of a variety of lesions in the central area.

Anatomy, Artistic↗
PubMed1998

Neuronal metabolic dysfunction in patients with cortical developmental malformations: a proton magnetic resonance spectroscopic imaging study.

Cortical developmental malformations are best diagnosed by MRI and are often the cause of refractory epilepsy. Little is known about the metabolic cell function on MR spectroscopy of these types of brain anomaly. We studied 23 patients with cortical developmental malformations and refractory epilepsy using proton MR spectroscopic imaging. Mean age was 28 years (range, 9 to 47 years). The lesions examined were focal cortical dysplasia (n = 5), heterotopia (four band, six periventricular, two subcortical), polymicrogyria (n = 3), tuberous sclerosis (n = 2), and polymicrogyria and periventricular nodular heterotopia (n = 1). We measured the relative signal intensity of N-acetylaspartate/creatine (NAA/Cr) in the lesion, in the perilesional region, and in the region remote from the visible lesion. The values were compared with those from similar brain regions of 25 normal control subjects. The mean NAA/Cr z score values for the 23 patients were as follows: lesion, -2.20 +/- 0.32 (mean +/- SE), n = 21; perilesional region, -1.01 +/- 0.38, n = 15; and distant region, -0.03 +/- 0.34, n = 18 (p < 0.0002). Despite the presence of a large number of neurons, heterotopia showed a relative decrease of NAA in some patients, suggesting that the neurons present were dysfunctional. The maximal NAA/Cr decrease, indicating metabolic dysfunction, colocalized to the structural malformation as defined by MRI and extended to normal-appearing regions adjacent to the visible lesion.

Adolescent↗
PubMed1998

Late-onset temporal lobe epilepsy and dilatation of the hippocampal sulcus by an enlarged Virchow-Robin space.

MRI signal changes within the hippocampal sulcus have been attributed to a dilated Virchow-Robin space within that sulcus, but no clinical correlates have previously been described. We present a 64-year-old man who developed right temporal seizures. MRI revealed an unusually enlarged Virchow-Robin space within the hippocampus, suggesting space-occupying effect. Such an abnormality should be considered a possible etiology in patients with late-onset temporal lobe epilepsy.

Age of Onset↗
PubMed1995

Curvilinear reconstruction of 3D magnetic resonance imaging in patients with partial epilepsy: a pilot study.

In an attempt to better delineate the abnormalities associated with focal cortical dysgenesis, we performed curvilinear reformatting of the cortex from 3D magnetic resonance (MR) images. Illustrative patients with partial seizures and conventional orthogonal MRI evaluation show that small regions of cortical thickening suggestive of focal dysplastic lesions may not be recognized. In three such patients the curvilinear reformatting demonstrated two additional focal abnormalities of the cortical gyri and better defined the two focal lesions found on conventional orthogonal MR images. This method promises to be a useful tool in the evaluation of epileptic patients with proven or suspected subtle structure cortical abnormalities, particularly focal neuronal migration disorders where cortical thickening, abnormal gyral pattern, and poor delineation of the gray-white matter transition are the main findings.

Brain Damage, Chronic↗
PubMedDate not supplied

[Retention of knowledge. III--Gynecology program].

The authors present the result of an educational investigation of knowledge retention concerning a Gynecology program. The research was developed by comparing the marks obtained in the fourth, fifth and sixth years. The examinations had the same content but were not identical. Between the fourth and fifth year, the loss of knowledge observed was -45.0% +/- 1.4% (average +/- standard error) and was not influenced by the time between the two examinations. The examinations between the fifth and sixth years indicated a gain of knowledge of +72.8% +/- 11.1% (average +/- standard error) and was influenced by the time between the two examinations.

Education, Medical↗