Transient Cerebral Arteriopathy (TCA) is one of the main causes of childhood stroke. Here we present an unusual case of Arterial Ischemic Stroke (AIS) caused by a TCA of posterior flow and originally located in the right thalamus. The detection of enterovirus in the cerebrospinal fluid allowed us to suppose a probable post infectious etiology. The course of symptoms was self-limited and the child had a complete clinical recovery after five days. A new ischemic lesion on the antero-inferior paravermian region of the left cerebellum was revealed by a following brain Magnetic Resonance Imaging (MRI) three months later and these findings were reported by further brain MRI control performed after 15 months. Comparing follow up Magnetic Resonance Angiography (MRA) with previous High Resolution Vessel Wall Magnetic Resonance Imaging (HRMI), we found a vessel narrowing at the level of the Posterior Inferior Cerebellar Artery that might explain the arteriopathy process. In conclusion, clinical and radiological course allow us to speculate that this multifocal cerebral arteriopathy might be a transient lesion due to enterovirus infection. To our knowledge, there are only three articles describing TCA enterovirus-related, and brain MRA was performed in only one case; in addition, no one with the involvement of the posterior circulation.
Benign childhood epilepsy with centrotemporal spikes (BECTS) has been investigated through EEG-fMRI with the aim of localizing the generators of the epileptic activity, revealing, in most cases, the activation of the sensory-motor cortex ipsilateral to the centrotemporal spikes (CTS). In this case report, we investigated the brain circuits hemodynamically involved by CTS recorded during wakefulness and sleep in one boy with CTS and a language disorder but without epilepsy. For this purpose, the patient underwent EEG-fMRI coregistration. During the "awake session", fMRI analysis of right-sided CTS showed increments of BOLD signal in the bilateral sensory-motor cortex. During the "sleep session", BOLD increments related to right-sided CTS were observed in a widespread bilateral cortical-subcortical network involving the thalamus, basal ganglia, sensory-motor cortex, perisylvian cortex, and cerebellum. In this patient, who fulfilled neither the diagnostic criteria for BECTS nor that for electrical status epilepticus in sleep (ESES), the transition from wakefulness to sleep was related to the involvement of a widespread cortical-subcortical network related to CTS. In particular, the involvement of a thalamic-perisylvian neural network similar to the one previously observed in patients with ESES suggests a common sleep-related network dysfunction even in cases with milder phenotypes without seizures. This finding, if confirmed in a larger cohort of patients, could have relevant therapeutic implication.
Two major isoforms of aquaporin-4 (AQP4) have been described in human tissue. Here we report the identification and functional analysis of an alternatively spliced transcript of human AQP4, AQP4-Δ4, that lacks exon 4. In transfected cells AQP4-Δ4 is mainly retained in the endoplasmic reticulum and shows no water transport properties. When AQP4-Δ4 is transfected into cells stably expressing functional AQP4, the surface expression of the full-length protein is reduced. Furthermore, the water transport activity of the cotransfectants is diminished in comparison to transfectants expressing only AQP4. The observed down-regulation of both the expression and water channel activity of AQP4 is likely to originate from a dominant-negative effect caused by heterodimerization between AQP4 and AQP4-Δ4, which was detected in coimmunoprecipitation studies. In skeletal muscles, AQP4-Δ4 mRNA expression inversely correlates with the level of AQP4 protein and is physiologically associated with different types of skeletal muscles. The expression of AQP4-Δ4 may represent a new regulatory mechanism through which the cell-surface expression and therefore the activity of AQP4 can be physiologically modulated.