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I J Namer

Publications and source records attributed to I J Namer.

At least 37 records · Page 2Linked to original sources
PubMed1994

Magnetic resonance imaging of antibody-mediated demyelinating experimental allergic encephalomyelitis.

Two models of demyelinating experimental allergic encephalomyelitis (EAE) were studied on Lewis rats in whom the disease was induced by injections of either (i) lentil-lectin binding myelin glycoproteins plus myelin basic protein (MBP)-specific T cells (36 rats), or (ii) myelin/oligodendrocyte glycoprotein-specific monoclonal antibody plus MBP-specific T cells (16 rats). In our 24 control rats, 20 received MBP-specific T cells only, and four received myelin glycoproteins plus purified protein derivative-specific T cells. The extent of the resulting blood-brain barrier (BBB) permeability, vasogenic oedema and/or demyelination was assessed in vivo using magnetic resonance imaging (MRI) techniques. The results show that in both demyelinating EAE models the disease appeared more quickly, progressed very rapidly and was more severe than when induced with a similar number of MBP-specific T cells alone. Almost all animals developed hyperacute EAE, with a very high mortality rate. MRI showed a very intense BBB breakdown and vasogenic oedema in all the normally 'leaky' areas of the central nervous system, and focal lesions corresponding to plaque formation in the brain stem or spinal cord near the 'leaky' areas. During the 40-day observation period, the rare survivors of this hyperacute form of EAE presented a chronic form of EAE with serious sequelae. Our results demonstrate that the synergistic effect observed between MBP-specific T cells and antibodies to myelin glycoproteins, especially to myelin/oligodendrocyte glycoprotein, does not only induce demyelinating lesions and chronic clinical signs, but is further responsible, via the normally 'leaky areas', for the fatal increase of the BBB breakdown and vasogenic oedema of which there are ample acute clinical signs.

Animals↗
PubMed1994

The role of Mycobacterium tuberculosis in experimental allergic encephalomyelitis.

Various detergents used in preparative membrane protein chemistry were added to a complete Freund's adjuvant/water emulsion in order to increase the solubility and/or immunologic availability of the Mycobacterium tuberculosis membrane and to explain its role in blood-brain barrier (BBB) permeability. Magnetic resonance imaging was used for in vivo determination of the BBB breakdown and cerebral edema. The results showed that with 1% 10 tridecyl ether, which increases emulsion stability, abundant BBB breakdown and cerebral edema were observed, similar to those encountered in experimental allergic encephalomyelitis (EAE). We suggest that the immunologic response triggered off by M. tuberculosis largely contributes to the BBB permeability changes observed during EAE, probably by an action on the endothelial cells of the cerebral blood vessels.

Animals↗
PubMed1994

[Magnetic Resonance Imaging study of the role of the blood-brain barrier in the pathogenesis of experimental allergic encephalomyelitis: application to multiple sclerosis].

Nuclear magnetic resonance imaging (MRI) proved to be, from the first, a very sensitive method, allowing the visualisation of multiple sclerosis lesions, yet which never permitted to establish a non equivocal relationship between the semeiology of such lesions and the clinical signs. The multifocal aspect of disseminated multiple sclerosis lesions is probably one of several factors accounting for this discrepancy. The study of an autoimmune disease, experimental allergic encephalomyelitis (EAE), regarded as a suitable model for multiple sclerosis in humans, has been performed using MRI in order to unravel the pathogenesis of the disease and apprehend the mechanisms responsible for the formation of multiple sclerosis lesions. The study focused on the part played by the blood-brain barrier (BBB) in the induction process of an autoimmune disease, since the central nervous system is normally screened from immunological supervision, by this barrier. Models both of acute EAE, induced by active or passive transfer of the antigen (myelin basic protein-MBP)--and chronic EAE, induced by passive transfer of MBP-specific T cells and myelin glycoproteins or MOG-specific monoclonal antibodies, have been reproduced, and their evolution followed up using high field MRI. Every time, the crucial role of the BBB was evidenced by the synchronism existing between the clinical signs, the appearance of lesions, preferentially in the most sensitive or permeable areas, and the BBB breakdown encouraged by the action of adjuvants. The physiopathological study of EAE using MRI is suggestive of the concept of systemic disease for multiple sclerosis, according to a two-step process, involving, in a first stage some primary viral or bacterial infection, causing T-cells to be sensitized to the host's own proteins by molecular mimicry, and in a second stage some bacterial infection or accidental circumstances which, resulting in a BBB breakdown, would provide immunocompetent cells with an opportunity to reach their target.

Animals↗
PubMed1993

Cerebral fat embolism studied with MRI and SPECT.

In a patient with fat embolism to the brain CT showed no abnormality. MRI performed after recovery from coma, when the patient had aphasia and quadriparesis, demonstrated multiple high signal abnormalities in the white matter on both T1- and T2-weighted images. HMPAO-SPECT showed left-sided hypoperfusion which resolved in parallel with clinical improvement 1 month later.

Adult↗
PubMed1993

An evaluation of the significance of areas of intense signal in the MR brain images of patients with multiple sclerosis.

This study evaluates the distribution of areas of intense signal (AIS) in 189 patients with multiple sclerosis (MS) and 83 patients presenting high-risk factors of cerebrovascular injuries. Two multivariate statistical analyses (multifactorial discriminant analysis and logistic regression analysis) with two AIS scores and several subpopulations of patients (according to age and/or the number of AIS) were tested. The results of these analyses were expressed with the usual screening test. The results obtained in this study even without the help of any clinical information are very promising, since they established that the specificity of MRI could be improved by using the distribution of the AIS in the various anatomical areas as a criterion. Five regions of the brain display were particularly significant in the discrimination between MS and non-MS patients: In decreasing order we found that the temporal, occipital, brain stem, and parietal regions were more specific with respect to the diagnosis of MS, while only the basal ganglia could account for non-MS patients. With multifactorial discriminant analysis and logistic regression analysis respectively, 78.9 (+/- 2.8)% and 85.1 (+/- 2.8)% of the patients were correctly classified by MRI. The results obtained on the main group were confirmed by a predictive test carried out on an other population of 40 patients, which produced similar results. The comparison between our method and Fazekas's imaging criteria showed a 20% improvement in favour of our approach and it is hoped that it will contribute to make the most of MRI as a tool for the diagnosis of MS.

Adolescent↗
PubMed1993

Quantitative cerebral magnetic resonance imaging during ACTH treatment of multiple sclerosis.

Serial MR scans were performed with the 2DFT imaging method and the filtered backprojection imaging method on 12 patients with multiple sclerosis in acute phase, 4 in a relapsing/remitting form, and 8 in a progressive form, before, during and after ACTH treatment. Both T1 and T2mono relaxation times, obtained by fitting transverse magnetization decay curves with a monoexponential function within the apparently normal white matter and the areas of increased signal, were measured. With the backprojection method it was possible to fit the transverse magnetization decay curve with a biexponential function and obtain T2long and T2short relaxation times. The T2mono and T1 relaxation times of the apparently normal white matter were significantly different from those obtained for volunteers, but no significant differences were found before, during, or after treatment. The transverse magnetization decay curves of the areas of increased signal were better fitted by a biexponential function. No significant changes in these relaxation times were observed after ACTH treatment. These results argue against an anti-oedematous action of ACTH and may suggest that it has an immunosuppressant effect.

Adrenocorticotropic Hormone↗
PubMed1993

Blood-brain barrier breakdown in MBP-specific T cell induced experimental allergic encephalomyelitis. A quantitative in vivo MRI study.

Blood--brain barrier permeability in myelin basic protein (MBP)-specific T cell induced experimental allergic encephalomyelitis (EAE) was studied by magnetic resonance imaging (MRI) in Lewis rats. Myelin basic protein-specific T cells of different specificity and/or purified protein derivative (PPD)-specific T cells were used. During the course of EAE, the volume of the lesions and the T1 and T2 relaxation times were recorded and evaluated with respect to the clinical signs. The results showed that the severity of abnormalities seen on MRI, corresponding to the blood--brain barrier breakdown and cerebral oedema depended on the following two factors: (i) the specificity of the MBP-specific T cells used; (ii) the number of MBP-specific T cells transferred. It was also shown that the more specific the cells were, the less severe the cerebral blood--brain barrier rupture. Moreover, the blood--brain barrier breakdown increased when the number of cells increased. Our results demonstrated that a synergy exists between MBP and PPD-specific T cells which seems to result in an increase in central nervous system inflammation. This helps to explain the role of Mycobacterium tuberculosis in the induction of EAE.

Animals↗
PubMed1992

In vivo dynamic MR imaging of MBP-induced acute experimental allergic encephalomyelitis in Lewis rat.

A dynamic in vivo study by MRI consisting of the measurement of relaxation times and in the visualization of the BBB permeability by Gd-DOTA was performed in an MBP-induced acute EAE model of Lewis rat. Fourteen rats were immunized with an MBP/CFA mixture, eight by CFA alone, and three control rats were used to test the harmless effect of repeatedly performed MRI examinations. Beginning on the 8th or 9th days and in parallel with the emergence of clinical signs, rats immunized by the MBP/CFA mixture showed slight increases of relaxation times and of the BBB permeability. These abnormalities, which always remain localized in the periventricular regions, become more pronounced toward the 10th and 11th days, just before (or at the same time) as paraplegia manifestations. After a plateau of a few days, they diminish with the clinical signs. This close correlation found in vivo establishes the essential role of BBB in the pathogenesis of clinical signs of this EAE model.

Animals↗
PubMed1991

Nuclear magnetic resonance T2 relaxation times in multiple sclerosis.

An original method was used to carry out the mathematical analysis of T2 transverse magnetization decay curves and the measure of T2 relaxation times on multiple sclerosis (MS) patients. The presumably normal white matter (WM) of these patients presented higher T2 relaxation times (98.6 msec), in comparison with that found in a population sample (88 msec). In this case, magnetization decay curves remain mostly monoexponential and are characterized by a single T2. On the other hand, areas of increased signal (AIS) curves are always better fitted by a biexponential function characterized by a short (82 msec) and a long (greater than 200 msec) T2. The spreading out of long T2 varies from one AIS to another in the same patient and among different patients; values of long T2 also vary with time, but without any correlation with the clinical state. In fact, no correlation was been established between relaxation times and clinical parameters. Quantitative MRI therefore enables a different approach to interpret MRI images; results suggest that several histobiochemical parameters play a role in the pathogenesis of an AIS and that MS is a dynamic and constantly evolving disease.

Adult↗
PubMed1991

The prognosis of subacute sclerosing panencephalitis in adults. Report of 8 cases and review of the literature.

In this article, 8 cases of subacute sclerosing panencephalitis (SSPE) are presented with a review of the literature. The symptoms developed during pregnancy in 2 cases. All of the patients died within 1 year duration except one. According to the reviewed literature, the prognosis in the adult cases is worse than in children; the two sexes are equally affected in adult SSPE.

Adolescent↗
PubMed1990

[A case of hemiballismus during cryptococcal meningitis].

We present a case of hemiballismus related to cryptococcal meningitis. A 23 year-old man was hospitalized because of involuntary movements of his left side, confusion, hyperpyrexia, neck stiffness, bilateral papilledema, right hemiparesis and bilateral pyramidal signs. Diagnosis was made by CSF examination demonstrating cryptococci by india ink. CT with contrast showed hyperdense lesions in the head of the right caudate nucleus, in the left internal capsule and in the frontal and occipital lobes. After treatment with amphotericin B, 5-fluorocytosine and haloperidol, he experienced rapid recovery with disappearance of hemiballismus. To our knowledge, this is the first report of hemiballismus caused by cryptococcal meningitis.

Adult↗
PubMed1989

Intravenously and iontophoretically administered naloxone reverses ischemic changes in rat hippocampus.

Forty rats under urethane anesthesia were subjected to cerebral ischemia by ligation of the right carotid, the right plus the left carotid, or the right carotid plus two vertebral arteries. Ischemia caused three types of changes in the field potential of the right hippocampal CA1 region evoked by fimbrial stimulation: 1) completely reversible deterioration (57% and 16% of the rats with unilateral and bilateral carotid artery ligation, respectively), 2) moderate deterioration (37% and 24% of the rats with unilateral and bilateral carotid artery ligation) and 3) irreversible loss of the evoked activity (6% and 60% of the rats with unilateral and bilateral carotid artery ligation and all the rats subjected to three-vessel occlusion). Naloxone improved the moderate deterioration in 10 of 11 rats (1-3 mg/kg i.v.) and in 15 of 16 (50-150 nA) iontophoretic applications, but naloxone did not restore the lost evoked activity. Intravenous morphine (10 mg/kg) aggravated the ischemic changes, and this effect was reversed by naloxone, while iontophoretic administration of morphine caused only excitation. These findings suggest that naloxone has a favorable effect on cerebral ischemia not severe enough to cause transmission failure. The reversal of ischemic changes by iontophoretic naloxone indicates that its site of action is at the neuronal or microcirculatory level.

Animals↗
PubMed1987

Spinal meningiomas.

Between the years of 1970-1982 29 spinal meningioma cases were operated on; 22 cases (76%) were female and 7 (24%) were male. The youngest patient was 16, and the oldest was 68 years old. On neurological examination, patients had neurological deficits in varying degrees. Diagnosis were done by myelography in all cases. Laminectomy was performed in all cases. 34.4% of cases were situated in cervical region and 65.6% were in thoracic region. 14% of the tumours were located extradurally and 68% were intradural. Multiple spinal meningioma was seen in only one case. One case died after operation; the mortality rate is 4%. 22 cases came for follow-up examination, 86.5% of them were in excellent or good condition. Only three cases showed no improvement.

Adolescent↗
PubMed1987

Peripheral nervous system involvement in Behçet's disease. Case report and review of the literature.

Central nervous system complication of Behçet's disease are well recognized. However, peripheral nervous system involvement has been rarely observed. A case of Behçet's disease with prominent peripheral nervous system involvement is reported in this article. The results of clinical, electromyographic, immunologic and electron-microscopic findings of a nerve biopsy are presented and discussed in the light of the literature.

Behcet Syndrome↗
PubMed1986

[Idiopathic localized paroxysmal hyperhidrosis. Treatment with clonidine].

Paroxysmal localized hyperhidrosis is a rare sign of a disorder of the autonomic nervous system. It has been reported in association with peripheral nerve, spinal cord and hypothalamic lesions and in some cases the etiology is unidentified. We present 12 cases of idiopathic paroxysmal localized hyperhidrosis and discuss the therapeutic effect and possible mechanism of clonidine which is a specific central nervous system alpha 2--adrenergic receptor agonist.

Acute Disease↗
PubMed1986

[Complex partial epileptic seizures as the initial symptom of subacute sclerosing panencephalitis].

A 18 year-old boy, without a previous history, presented with psychomotor seizures and, 4 months after, mental deterioration. EEG showed focal epileptic abnormalities characterized by high amplitude spike waves in the left temporal region. Periodic complexes appeared after administration of Diazepam. CT scan showed mild cortical atrophy in the left temporal region. Measles virus HI antibody titers were 1/2048 in the serum and 1/64 in the CSF. The patient died one year after the first complex partial seizures.

Adolescent↗
PubMed1985

[Primary carcinoma of the choroid plexus. 2 case reports and review of the literature].

Primary Carcinomas of Choroid Plexus are seen rarely. In previous literature there were 37 cases which were reported according to Lewis and Russel-Rubinstein malignancy criterias. In this article, we describe 5 years old boy and 1.5 year old girl who suffered from cerebellar ataxia and intracranial pressure increase syndrome. In case 1, the tumor of the fourth ventricle was diagnosed by brachial angiography and ventriculography. In case 2, the diagnosis was established by CT scan. In case 1, the patient died during the postoperative course. In case 2, the postoperative time was unremarkable. A radiotherapy of 3 000 rads was applied to the posterior fossa. One year later, the patient had only mild ataxia.

Adolescent↗