JC Virus Granule Cell Neuronopathy and Lymphoma.

Neurological opportunistic infections are going to increase. Clinicians should be aware of the neurological spectrum of JC virus manifestations, including granule cell neuronopathy. Detection of JC virus DNA by polymerase chain reaction in cerebrospinal fluid should be realized in the assessment of a progressive cerebellar ataxia in an immunocompromised patient.

Unusual Aspect of Posterior Reversible Encephalopathy Syndrome in an Elderly Adult.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) classically occurs in patients presenting with a sudden increase of arterial pressure or eclampsia, but the range of etiologies is very wide. Although the mechanisms underlying PRES remain unclear, research suggests that when the extent of hypertension exceeds the threshold of cerebral blood flow autoregulation, this induces blood-brain barrier disruption that leads to brain edema. Unusual presentations on magnetic resonance imaging (MRI) are possible, including the involvement of frontal or temporal lobes, cerebellar hemispheres, basal ganglia, brainstem, or deep white matter. However, in these atypical locations, edema is mostly accompanied by the classical parieto-occipital region involvement. CASE REPORT: We report the case of an elderly adult presenting with an unusual presentation of PRES with exclusive involvement of the frontal lobes, associated with severe hypertension. In our case, computed tomography and MRI abnormalities were exclusively localized in the frontal regions without involvement of the classical parieto-occipital regions. A favorable clinical course after hypertension management and complete clearance on an MRI scan at 3 months' follow-up confirmed the diagnosis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: PRES is a condition potentially encountered by many doctors, especially in the emergency department. However, atypical clinical or imaging presentations are possible and could delay the diagnosis. These must be known to begin adequate treatment as quickly as possible.

Voltage-gated potassium channel antibody paraneoplastic limbic encephalitis associated with acute myeloid leukemia.

Among paraneoplastic syndromes (PNS) associated with malignant hemopathies, there are few reports of PNS of the central nervous system and most of them are associated with lymphomas. Limbic encephalitis is a rare neurological syndrome classically diagnosed in the context of PNS. We report the case of a 81-year-old man who presented with a relapsed acute myeloid leukemia (AML) with minimal maturation. He was admitted for confusion with unfavorable evolution as he presented a rapidly progressive dementia resulting in death. A brain magnetic resonance imaging, performed 2 months after the onset, was considered normal. An electroencephalogram showed non-specific bilateral slow waves. We received the results of the blood screening of neuronal autoanti-bodies after the patient's death and detected the presence of anti-voltage-gated potassium channel (VGKC) antibodies at 102 pmol/l (normal at <30 pmol/l). Other etiologic studies, including the screening for another cause of rapidly progressive dementia, were negative. To our knowledge, this is the first case of anti-VGKC paraneoplastic limbic encephalitis related to AML.

A hierarchical modeling approach of hippocampus local circuit.

The modeling and simulation of a realistic nervous tissue are difficult because of the number of implied cell types (neuronal and glial), the topology of the networks, and the various heterogeneous molecular mechanisms. The MTIP (Mathematical Theory of Integrative Physiology) is used as a new modeling approach based on a representation in terms of functional interactions and a formalism (S-Propagator) related to n-level field theory. This work presents the passage from a theoretical description of the biological system to a computing implementation in the general case. The specific case of the hippocampus is presented, as well as how a drug allows learning and memory improvement in the local circuit of the CA1 area of the hippocampus. This in silico result is used to experimentally predict the drug effect in vitro to confirm the accuracy of MTIP.