Myasthenia gravis without chronic GVHD after allogeneic bone marrow transplantation.

in Bone Marrow Transplantation (1998), 22(2), 197-200

A 20-year-old man with aplastic anemia developed myasthenia gravis (MG) 7 months after bone marrow transplantation (BMT) from an HLA one locus-mismatched sister. Proximal muscle weakness (predominant in ... [more ▼]

A 20-year-old man with aplastic anemia developed myasthenia gravis (MG) 7 months after bone marrow transplantation (BMT) from an HLA one locus-mismatched sister. Proximal muscle weakness (predominant in the lower limbs) and dysphagia occurred without any other sign of graft-versus-host disease (GVHD), 1 month after cessation of immunosuppression with cyclosporine. The diagnosis of MG was based on clinical symptoms and on neurophysiologic investigations showing a significant increase of the Jitter in single-fiber electromyography and a significant decremental response during repetitive stimulation at slow rates, but antibodies against the acetylcholine receptor (AchRab) were negative. All clinical and neurophysiological signs normalized within 1 month of treatment with low-dose prednisolone and pyridostigmine, and the patient is perfectly well 1 year after cessation of all therapy. All cases of BMT-associated MG previously published are reviewed in comparison with ours. The originality of this new observation is that this case is the only one not associated with chronic GVHD and negative for AchRab. Alternatively, MG may have been the sole manifestation of chronic GVHD in this patient. [less ▲]

Myasthenia gravis without chronic GVHD after allogenic bone marrow transplantation

Conference (1997)

Serotonin 5HT2 receptor imaging in the human brain using positron emission tomography and a new radioligand, [18F]altanserin: results in young normal controls.

in Journal of Cerebral Blood Flow & Metabolism (1995), 15(5), 787-97

Changes in serotonin-2 receptors have been demonstrated in brain autopsy material from patients with various neurodegenerative and affective disorders. It would be desirable to locate a ligand for the ... [more ▼]

Changes in serotonin-2 receptors have been demonstrated in brain autopsy material from patients with various neurodegenerative and affective disorders. It would be desirable to locate a ligand for the study of these receptors in vivo with positron emission tomography (PET). Altanserin is a 4-benzoylpiperidine derivative with a high affinity and selectivity for S2 receptors in vitro. Dynamic PET studies were carried out in nine normal volunteers with high-specific activity (376-1,680 mCi/mumol) [18F]altanserin. Arterial blood samples were obtained and the plasma time-activity curves were corrected for the presence of labeled metabolites. Thirty minutes after injection, selective retention of the radioligand was observed in cortical areas, while the cerebellum, caudate, and thalamus had low radioactivity levels. Specific binding reached a plateau between 30 and 65 min postinjection at 1.8% of the injected dose/L of brain and then decreased, indicating the reversibility of the binding. The total/nonspecific binding ratio reached 2.6 for times between 50 and 70 min postinjection. The graphical analysis proposed by Logan et al. allowed us to estimate the binding potential (Bmax/KD). Pretreatment with ketanserin was given to three volunteers and brain activity remained uniformly low. An additional study in one volunteer showed that [18F]altanserin can be displaced from the receptors by large doses of ketanserin. At the end of the study, unchanged altanserin was 57% of the total plasma activity. These results suggest that [18F]altanserin is selective for S2 receptors in vivo as it is in vitro. They indicate that [18F]altanserin is suitable for imaging and quantifying S2 receptors with PET in humans. [less ▲]

Differential diagnosis of Alzheimer's disease with PET.

in Journal of Nuclear Medicine : Official Publication, Society of Nuclear Medicine (1994), 35(3), 391-8

PET studies have demonstrated bilateral temporo-parietal hypoperfusion and hypometabolism in probable and definite Alzheimer's disease (AD), a pattern that may help differentiate AD from other dementias ... [more ▼]

PET studies have demonstrated bilateral temporo-parietal hypoperfusion and hypometabolism in probable and definite Alzheimer's disease (AD), a pattern that may help differentiate AD from other dementias. METHODS: To evaluate the diagnostic power of cerebral metabolic distribution patterns for "cortical" degenerative dementias, PET scans obtained from 129 patients referred for differential diagnosis of dementia were analyzed visually. RESULTS: Sixty-five patients had a final clinical diagnosis of probable AD. Ninety-seven percent (97%) of those had abnormal metabolic scans and 94% showed a suggestive pattern of bilateral or unilateral temporo-parietal hypometabolism (with or without frontal involvement). Hypometabolism was unilateral in 23% of patients. Five subjects with a neuropathologically proven diagnosis of Alzheimer's disease had a suggestive metabolic pattern. One of those was an early case with frontal hypometabolism exceeding temporo-parietal involvement. Two patients with Alzheimer's-type dementia had isolated bilateral frontal hypometabolism. CONCLUSIONS: This alternative metabolic pattern may correspond to a non-Alzheimer pathology occurring in 10%-20% of patients suffering from clinically probable Alzheimer's disease. Most of the patients with possible but atypical Alzheimer's-type dementia showed isolated bilateral frontal involvement. This metabolic pattern probably corresponds to different diseases, such as Pick's disease, frontal lobe dementia or progressive subcortical gliosis. [less ▲]

Epilepsie frontale et trouble du comportement: diagnostic, exploration et traitement

in 30ème Congrès de l'Association des Pédiatres de Langue Française (1993)

Cerebral Glucose Utilization During Stage 2 Sleep in Man

in Brain Research (1992), 571(1), 149-53

Using [18F]fluorodeoxyglucose method and positron emission tomography, we performed paired determinations of the cerebral glucose utilization at one week intervals during sleep and wakefulness, in 12 ... [more ▼]

Using [18F]fluorodeoxyglucose method and positron emission tomography, we performed paired determinations of the cerebral glucose utilization at one week intervals during sleep and wakefulness, in 12 young normal subjects. During 6 of 28 sleep runs, a stable stage 2 SWS was observed that fulfilled the steady-state conditions of the model. The cerebral glucose utilization during stage 2 SWS was lower than during wakefulness, but the variation did not significantly differ from zero (mean variation: -11.5 +/- 25.57%, P = 0.28). The analysis of 89 regions of interest showed that glucose metabolism differed significantly from that observed at wake in 6 brain regions, among them both thalamic nuclei. We conclude that the brain energy metabolism is not homogeneous throughout all the stages of non-REMS but decreases from stage 2 SWS to deep SWS; we suggest that a low thalamic glucose metabolism is a metabolic feature common to both stage 2 and deep SWS, reflecting the inhibitory processes observed in the thalamus during these stages of sleep. Stage 2 SWS might protect the stability of sleep by insulating the subject from the environment and might be a prerequisite to the full development of other phases of sleep, especially deep SWS. [less ▲]

Plasticité des neurones sensoriels primaires chez le rat adulte. Etude in vitro et in vivo.

Conference (1991, November 16)

Decrease of Frontal Metabolism Demonstrated by Positron Emission Tomography in a Population of Healthy Elderly Volunteers

in Acta Neurologica Belgica (1991), 91(5), 288-95

Frontal metabolism measured with positron emission tomography is shown to be decreased relatively to that in other cortical or sub-cortical areas, in a population of healthy elderly compared to young ... [more ▼]

Frontal metabolism measured with positron emission tomography is shown to be decreased relatively to that in other cortical or sub-cortical areas, in a population of healthy elderly compared to young volunteers. Cortical atrophy or neuronal depopulation are unlikely to entirely explain this physiological phenomenon, and sub-cortico-cortical deactivation should play a role, analogous to that proposed in subcortical diseases. [less ▲]

[18F]Altansérine: nouveau radioligand des récepteurs sérotoninergiques pour la tomographie par émission de positons (TEP)

Poster (1990, August 22)

Cerebral Glucose Utilization During Sleep-Wake Cycle in Man Determined by Positron Emission Tomography and [18f]2-Fluoro-2-Deoxy-D-Glucose Method

in Brain Research (1990), 513(1), 136-43

Using the [18F]fluorodeoxyglucose method and positron emission tomography, we studied cerebral glucose utilization during sleep and wakefulness in 11 young normal subjects. Each of them was studied at ... [more ▼]

Using the [18F]fluorodeoxyglucose method and positron emission tomography, we studied cerebral glucose utilization during sleep and wakefulness in 11 young normal subjects. Each of them was studied at least thrice: during wakefulness, slow wave sleep (SWS) and rapid eye movement sleep (REMS), at 1 week intervals. Four stage 3-4 SWS and 4 REMS fulfilled the steady state conditions of the model. The control population consisted of 9 normal age-matched subjects studied twice during wakefulness at, at least, 1 week intervals. Under these conditions, the average difference between the first and the second cerebral glucose metabolic rates (CMRGlu was: -7.91 +/- 15.46%, which does not differ significantly from zero (P = 0.13). During SWS, a significant decrease in CMRGlu was observed as compared to wakefulness (mean difference: -43.80 +/- 14.10%, P less than 0.01). All brain regions were equally affected but thalamic nuclei had significantly lower glucose utilization than the average cortex. During REMS, the CMRGlu were as high as during wakefulness (mean difference: 4.30 +/- 7.40%, P = 0.35). The metabolic pattern during REMS appeared more heterogeneous than at wake. An activation of left temporal and occipital areas is suggested. It is hypothetized that energy requirements for maintaining membrane polarity are reduced during SWS because of a decreased rate of synaptic events. During REMS, cerebral glucose utilization is similar to that of wakefulness, presumably because of reactivated neurotransmission and increased need for ion gradients maintenance. [less ▲]