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Background We report a rare case of unruptured middle cerebral artery aneurysm associated with moyamoya disease. Case Description A 48-year-old woman with an 8-year history of moyamoya disease developed a de novo aneurysm at the bifurcation of the right middle cerebral artery. The aneurysm showed rapid enlargement in size in 1 year and surgical treatment was performed. Preoperative images could not clearly define the anatomical relationship between the aneurysm and the surrounding vessels. Intraoperative findings indicated that segmental occlusion of normal arteries that was not visualized made it difficult to define the vascular anatomy. In addition, those occlusions accompanied by improved M1 flow after administration of cilostazol was speculated to have increased hemodynamic stress, leading to the relatively rapid progress of the aneurysm. Conclusions Understanding the complexity of such process may be valuable in proper decision-making in the management of moyamoya disease patients.

Oligodendrogliomas are diffuse gliomas located in the cerebral hemisphere, and the MRI typically show swollen cortex and subcortical white matter by the tumor cells. IDH mutation and 1p/19q co-deletion define oligodendrogliomas in WHO classification, and these genetic alterations are associated with good response to chemo-radiation therapy and better prognosis compared to the IDH-mutant astrocytomas. We reviewed MRI findings of 60 oligodendrogliomas with 1p/19q co-deleted tumors which were diagnosed at Dokkyo Medical University since 1999. Of those, 3 cases showed highly infiltrating pattern in which tumors were more predominant in the white matter than the cortex and the infiltration involved multiple lobes. We retrospectively investigated those 3 cases for histological features, treatment, and clinical outcome. There were 2 males and 1 female. MRI showed faint-brushed Gd enhancement around the center of the tumor-infiltrated area in 1 case, while there was no enhancing lesion in other 2 cases. All three underwent stereotactic biopsy. Histologically, all 3 cases lacked typical oligodendroglioma morphology: the tumor cells have irregular round, oval to elongated nuclei without perinuclear halo and had dense, closed chromatin similar to astrocytoma. Two cases underwent chemotherapy (TMZ and PAV accordingly), without radiation and 1 case underwent chemotherapy with radiation as the primary treatment. Interestingly, all three tumors responded well not only to the primary treatments but also to the radiation therapy administered after recurrence, although all eventually succumbed to the tumor. PFS were 16, 37, 67 months and OS were 104, 70, 115 months for each, which were at the worse end as oligodendrogliomas but are apparently better than astrocytomas. Highly infiltrating oligodendrogliomas appeared to show significantly different MRI and histological features from typical oligodendrogliomas that primarily involve cerebral cortex. The underlying mechanism of such differences might involve specific genetic alterations and/or gene expression alterations that may not affect treatment response.

The spontaneous activity pattern of cortical neurons in dissociated culture is characterized by burst firing that is highly synchronized among a wide population of cells. The degree of synchrony, however, is excessively higher than that in cortical tissues. Here, we employed polydimethylsiloxane (PDMS) elastomers to establish a novel system for culturing neurons on a scaffold with an elastic modulus resembling brain tissue, and investigated the effect of the scaffold's elasticity on network activity patterns in cultured rat cortical neurons. Using whole-cell patch clamp to assess the scaffold effect on the development of synaptic connections, we found that the amplitude of excitatory postsynaptic current, as well as the frequency of spontaneous transmissions, was reduced in neuronal networks grown on an ultrasoft PDMS with an elastic modulus of 0.5 kPa. Furthermore, the ultrasoft scaffold was found to suppress neural correlations in the spontaneous activity of the cultured neuronal network. The dose of GsMTx-4, an antagonist of stretch-activated cation channels (SACs), required to reduce the generation of the events below 1.0 event/min on PDMS substrates was lower than that for neurons on a glass substrate. This suggests that the difference in the baseline level of SAC activation is a molecular mechanism underlying the alteration in neuronal network activity depending on scaffold stiffness. Our results demonstrate the potential application of PDMS with biomimetic elasticity as cell-culture scaffold for bridging the in vivo-in vitro gap in neuronal systems., 23 pages, 6 figures

Multielectrode arrays (MEAs) are versatile tools that are used for chronic recording and stimulation of neural cells and tissues. Driven by the recent progress in understanding of how neuronal growth and function respond to scaffold stiffness, development of MEAs with a soft cell-to-device interface has gained importance not only for in vivo but also for in vitro applications. However, the passivation layer, which constitutes the majority of the cell-device interface, is typically prepared with stiff materials. Herein, a fabrication of an MEA device with an ultrasoft passivation layer is described, which takes advantage of inkjet printing and a polydimethylsiloxane (PDMS) gel with a stiffness comparable to that of the brain. The major challenge in using the PDMS gel is that it cannot be patterned to expose the sensing area of the electrode. This issue is resolved by printing 3D micropillars at the electrode tip. Primary cortical neurons are grown on the fabricated device, and effective stimulation of the culture confirms functional cell-device coupling. The 3D MEA device with an ultrasoft interface provides a novel platform for investigating evoked activity and drug responses of living neuronal networks cultured in a biomimetic environment for both fundamental research and pharmaceutical applications.