Regulated RNA translation is critical to provide proteins needed to maintain persistent modification of synaptic strength, which underlies the molecular basis of long-term memory (LTM). Cytoplasmic polyadenylation element-binding proteins (CPEBs) are sequence-specific RNA-binding proteins and regulate translation in various tissues. All four CPEBs in vertebrates are expressed in the brain, including the hippocampal neurons, suggesting their potential roles in translation-dependent plasticity and memory. Although CPEB1 and CPEB3 have been shown to control specific kinds of hippocampus-related LTM, the role of CPEB2 and CPEB4 in learning and memory remains elusive. Thus, we generated CPEB4 knockout (KO) mice and analyzed them using several behavioral tests. No difference was found in the anxiety level, motor coordination, hippocampus-dependent learning and memory between the KO mice and their wild-type (WT) littermates. Electrophysiological recordings of multiple forms of synaptic plasticity in the Schaffer collateral pathway-CA1 neurons also showed normal responses in the KO hippocampal slices. Morphological analyses revealed that the CPEB4-lacking pyramidal neurons possessed slightly elongated dendritic spines. Unlike its related family members, CPEB1 and CPEB3, CPEB4 seems to be dispensable for hippocampus-dependent plasticity, learning and memory.

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Introduction: Hyperthyroidism-related anterior circulation ischemic events have been well documented; however, posterior circulation infarction is rarely reported, not to mention with superior mesenteric artery syndrome (SMAS), which has never been reported concurrently. We describe, to the best of our knowledge, the first case of hyperthyroidism-related cerebellar infarction accompanied with SMAS. Patient concerns: A 22-year-old women presented with palpitation, postprandial vomiting, and acute body weight loss. Enlarged thyroid gland was discovered in physical examination and Graves disease was diagnosed by blood test; therefore, Propylthiouracil and β-blocker were prescribed. Sudden onset conscious disturbance accompanied with apnea was noted during hospitalization. Diagnosis: Computed tomography (CT) revealed cerebellar infarction with severe cerebellar swelling and tonsil herniation; hence, emergent suboccipital craniotomy and bilateral tonsillectomy were performed. Interventions: Nevertheless, persisted poor passage of liquid diet during nasogastric tube feeding was noted after operation. CT of abdomen showed a sharp aorta-SMA angle (15°) and a short distance between aorta and SMA (6 mm) indicating a diagnosis of SMAS. Outcomes: After parental nutrition supplement and progressive rehabilitation program, she recovered to a modified Rankin Scale of 3. Conclusion: Although rarely reported, hyperthyroidism-related sympathetic hyperstimulation, vasculopathy could result in potentially deadly posterior circulation infarction. Furthermore, SMAS should be considered in the cases of hyperthyroidism with prolonged gastrointestinal symptoms even after treatment and should be treated simultaneously, since SMAS exacerbates depletion of intravascular volume. Further study to clarify the relation between hyperthyroidism and posterior circulation hemodynamic status is suggested.

This study proposed a new object feature extraction method that employs the quadtree decomposition. In the proposed method, we segmented the image into variable sized blocks, named homogeneous blocks, which are the units of feature extraction process. Because the quadtree decomposition can highlight the details of images, more feature information can be extracted from the visual important objects than from the monotone areas of the image. The experimental results show the image retrieval performance is effectively improved as compared with the pixel based method.

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