SUMMARYLignin, one of the main structural polymer of plant cell walls, varies in amount and monomeric composition among tissue and cell types, as well as among plant species. However, few analytical methods are available that can conveniently and accurately determine the morphological distribution of lignin units at the cellular level. In this report, we used time-of-flight secondary ion mass spectrometry (TOF-SIMS) to directly map guaiacyl (G) and syringyl (S) lignin units in several successive growth rings of the maple xylem. TOF-SIMS imaging and a semiquantitative approach revealed clear difference in the annual distribution of lignins between the fiber and vessel. While the vessel walls were constantly G-rich with varied S/G ratios through a growth ring, the fibers showed fairly regular annual distribution of lignins in which the earlywood was S-rich with an almost constant S/G ratio and the latewood was G-rich resulting from a decrease of the S unit. The reliability of TOF-SIMS results was demonstrated by its high correlation with the results of thioacidolysis on radial distribution of the S/G ratio in several contiguous tree rings and also in the latewood and earlywood of each ring. These results indicate that TOF-SIMS allows direct visualization of lignin composition in plant tissues.

Perivascular regions of the brain harbor multipotent stem cells. We previously demonstrated that brain pericytes near blood vessels also develop multipotency following experimental ischemia in mice and these ischemia-induced multipotent stem cells (iSCs) can contribute to neurogenesis. However, it is essential to understand the traits of iSCs in the poststroke human brain for possible applications in stem cell-based therapies for stroke patients. In this study, we report for the first time that iSCs can be isolated from the poststroke human brain. Putative iSCs were derived from poststroke brain tissue obtained from elderly stroke patients requiring decompressive craniectomy and partial lobectomy for diffuse cerebral infarction. Immunohistochemistry showed that these iSCs were localized near blood vessels within poststroke areas containing apoptotic/necrotic neurons and expressed both the stem cell marker nestin and several pericytic markers. Isolated iSCs expressed these same markers and demonstrated high proliferative potential without loss of stemness. Furthermore, isolated iSCs expressed other stem cell markers, such as Sox2, c-myc, and Klf4, and differentiated into multiple cells in vitro, including neurons. These results show that iSCs, which are likely brain pericyte derivatives, are present within the poststroke human brain. This study suggests that iSCs can contribute to neural repair in patients with stroke.

The data of the nationwide prospective registry of acute cerebral large vessel occlusion (LVO; RESCUEJapan Registry) were analyzed to know the effect of edaravone, a free radical scavenger, on clinical outcome at 90 days after onset. In this registry, patients with acute cerebral LVO admitted within 24 h after onset were prospectively registered.

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Hyperperfusion syndrome (HPS) after carotid artery stenting (CAS) may cause hemorrhagic or ischemic events leading to serious sequelae. We previously reported the staged angioplasty (SAP) to prevent HPS. In the present study, we analyzed our treatment results of SAP to know its effectiveness and problems. The study included 43 patients scheduled for SAP in whom preoperative single photon emission computed tomography (SPECT) showed severely impaired cerebral blood flow (CBF). The analyzed subjects were 38 males and 4 females, mean age was 73 ± 8.5 years old. SAP was indicated for the patients whose CBF ratio in the affected/unaffected hemisphere (asymmetry index) was below 0.8, and cerebrovascular reactivity measured by acetazolamide challenge was below 10%. First, percutaneous transluminal angioplasty (PTA) was performed. If PTA was successful, CAS was performed 2 weeks later. If PTA was not successful due to inadequate dilatation or extensive dissection, a stent was placed. SPECT was performed immediately after PTA and CAS to confirm the presence or absence of hyperperfusion phenomenon (HPP) indicating radiologic hyperperfusion. In 39 of 43 patients (91%), SAP was successfully performed and HPP was not observed. On the other hand, in the other four patients (9%), immediate stent placement was added due to inadequate dilatations in three patients and vascular dissection in one. Among 43 candidates for SAP, 41 patients (95.4%) had favorable course, but one hemorrhagic and one ischemic complications were observed after PTA. SAP was a relatively simple procedure, and its clinical results seemed acceptable.