Striatal Blood Flow Changes by Middle Cerebral Artery Occlusion and Its Effect on Neurological Deficits in Mice.

OBJECTIVE: We attempted to record the regional cerebral blood flow (CBF) simultaneously at various regions of the cerebral cortex and the striatum during middle cerebral artery (MCA) occlusion and to evaluate neurological deficits and infarct formation. METHODS: In male C57BL/6J mice, CBF was recorded in three regions including the ipsilateral cerebral cortex and the striatum with laser Doppler flowmeters, and the origin of MCA was occluded with a monofilament suture for 15-90 min. After 48 h, neurological deficits were evaluated, and infarct was examined by triphenyltetrazolium chloride (TTC) staining. RESULTS: CBF decrease in the striatum was approximately two-thirds of the MCA-dominant region of the cortex during MCA occlusion. The characteristic CBF fluctuation because of spontaneously occurred spreading depolarization observed throughout the cortex was not found in the striatum. Ischemic foci with slight lower staining to TTC were found in the ipsilateral striatum in MCA-occluded mice for longer than 30 min (n = 54). Twenty-nine among 64 MCA-occluded mice exhibited neurological deficits even in the absence of apparent infarct with minimum staining to TTC in the cortex, and the severity of neurological deficits was not correlated with the size of the cortical infarct. CONCLUSION: Neurological deficits might be associated with the ischemic striatum rather than with cortical infarction.

Severe complication subsequent to surgical site infection after cervical laminoplasty: a case report.

INTRODUCTION: Surgical site infections (SSI) following spinal surgery can result in serious complications. Although early detection and intensive care are essential to minimize possible sequelae, more than one surgical intervention is required to alleviate the infection in some cases. CASE PRESENTATION: A 66-year-old man with long-standing Parkinson's disease (PD) developed SSIs after cervical laminoplasty. Despite surgical debridement and irrigation, his neurological status worsened severely and anterior infectious involvement at the C4-5 level was identified by magnetic resonance imaging. He underwent another urgent surgery for anterior debridement and iliac bone grafting. His laboratory results gradually normalized with antibiotic therapy, and his neurological status improved. One year after surgery, he was ambulatory with walker assistance. However, his right hand remained difficult to control with significant sensory loss and numbness. DISCUSSION: To our knowledge, this is the first case of SSI that extended rapidly to the anterior side despite immediate and intensive treatment in a patient with PD after laminoplasty. During SSI treatment, meticulous observation should be performed to check for exacerbations.

Rivaroxaban Promotes Reduction of Embolus Size within Cerebrocortical Microvessels in a Mouse Model of Embolic Stroke.

Previous reports have suggested that direct oral anticoagulants exert a prothrombolytic effect against intracardiac thrombi. We hypothesized that these anticoagulants may also help recanalize occluded intracranial arteries via prothrombolytic effects. In this study, we evaluated the effects of rivaroxaban, a direct oral anticoagulant, on fibrin emboli within the cerebrocortical microvessels in a mouse model of embolic stroke. Fibrin emboli prepared ex vivo were injected into the common carotid artery of male C57BL/6 mice, and embolization in the microvessels on the brain surface was observed through a cranial window. Oral administration of rivaroxaban was initiated a week before injection of the emboli. The number and sizes of the emboli were measured at two time points: immediately after and 3 h after the embolus injection in the rivaroxaban-treated mice (n =6) and untreated mice (n =7). The rates of recanalization and change in the embolus size were analyzed between the two groups. Complete recanalization was observed only in the rivaroxaban group (three mice in the rivaroxaban group compared with none in the control group). A significantly higher rate of reduction of the embolus size was observed in the rivaroxaban group than in the control group (P=0.0216). No significant differences between the two groups were observed in the serum levels of the following coagulation markers: thrombin-antithrombin III complexes, D-dimers, or plasmin-α2-plasmin inhibitor complex. Our findings indicate that rivaroxaban may promote reduction in the size of stagnated fibrin emboli in cerebrocortical microvessels in cases of embolic stroke.

Neuroprotective Role of Astroglia in Parkinson Disease by Reducing Oxidative Stress Through Dopamine-Induced Activation of Pentose-Phosphate Pathway.

Oxidative stress plays an important role in the onset and progression of Parkinson disease. Although released dopamine at the synaptic terminal is mostly reabsorbed by dopaminergic neurons, some dopamine is presumably taken up by astroglia. This study examined the dopamine-induced astroglial protective function through the activation of the pentose-phosphate pathway (PPP) to reduce reactive oxygen species (ROS). In vitro experiments were performed using striatal neurons and cortical or striatal astroglia prepared from Sprague-Dawley rats or C57BL/6 mice. The rates of glucose phosphorylation in astroglia were evaluated using the [14C]deoxyglucose method. PPP activity was measured using [1-14C]glucose and [6-14C]glucose after acute (60 min) or chronic (15 hr) exposure to dopamine. ROS production was measured using 2',7'-dichlorodihydrofluorescein diacetate. The involvement of the Kelch-like ECH-associated protein 1 (Keap1) or nuclear factor-erythroid-2-related factor 2 (Nrf2) system was evaluated using Nrf2 gene knockout mice, immunohistochemistry, and quantitative reverse transcription polymerase chain reaction analysis for heme oxygenase-1. Acute exposure to dopamine elicited increases in astroglial glucose consumption with lactate release. PPP activity in astroglia was robustly enhanced independently of Na+-dependent monoamine transporters. In contrast, chronic exposure to dopamine induced moderate increases in PPP activity via the Keap1/Nrf2 system. ROS production from dopamine increased gradually over 12 hr. Dopamine induced neuronal cell damage that was prevented by coculturing with astroglia but not with Nrf2-deficient astroglia. Dopamine-enhanced astroglial PPP activity in both acute and chronic manners may possibly reduce neuronal oxidative stress.

Diameter of fluorescent microspheres determines their distribution throughout the cortical watershed area in mice.

A hemodynamic mechanism has long been assumed to play an important role in watershed infarction. In recent years, however, clinical evidence has indicated that an embolic mechanism is involved. The mechanism by which emboli are trapped preferentially in watershed areas remains unclear. In the present study, we developed a mouse embolus model using fluorescent microspheres with different diameters and evaluated the role of the microspheres' diameters in the generation of a watershed-patterned distribution. We injected fluorescent microspheres of four different diameters (i.e., 13, 24, 40, and 69 µm) into the internal carotid artery of C57BL/6 mice either (1) without ligation of the common carotid artery (normal perfusion pressure model: NPPM) or (2) with ligation of the common carotid artery (low perfusion pressure model: LPPM). Left common carotid artery ligation induced reductions in local cerebral blood flow in both the periphery and the core area of the left middle cerebral artery. A greater reduction in the border-zone area between the left anterior cerebral artery and the middle cerebral artery was also noted. After 24 h, the brains were removed and the distribution of the microspheres in the brain was evaluated using a fluorescence microscope. The 24-µm microspheres were distributed in the watershed area more frequently than the other microsphere sizes (P < .05, ANOVA followed by Tukey's test). Meanwhile, the distribution rates were similar between the NPPM and LPPM models for all microsphere sizes. This study suggested that the distribution pattern of the microspheres was only affected by the microspheres' diameters.

Osteochondral lesion of the tibial plafond treated with a retrograde osteochondral autograft: a report of two cases.

BACKGROUND: Osteochondral lesions (OCLs) of the tibial plafond (OLTPs) are rare, and few studies provide treatment recommendations. We describe two cases of an OLTP that were treated with retrograde osteochondral autograft. CASE REPORTS: The first case was a 27-year-old basketball player and the second case was a 38-year-old soccer player. We harvested osteochondral autografts from the nonweight-bearing area of the lateral femoral condyle of the patient's ipsilateral knees. The grafts were reversed and inserted into the bone tunnel reaching the OLTPs starting proximally and moving distally. The first patient was able to play professional basketball 14 months after the procedure and continues to play 5 years and 6 months later. The second patient was able to play recreational soccer 9 months after the procedure and continues to play 4 years later. CONCLUSION: Use of the retrograde osteochondral autograft produced satisfactory results including the return to sports. The retrograde osteochondral autograft can be considered recommendable for treating OLTPs.

Glomus Tumor in the Tarsal Tunnel: A Case Report.

Glomus tumors are painful benign neoplasms. They commonly present in the hand and are mostly solitary lesions. We report a rare case of multiple glomus tumors in the lower leg. Moreover, 1 of the tumors was in the tarsal tunnel. Resection of the tumors resulted in the early diagnosis of glomus tumors and complete symptom relief. Because of its rarity, diagnosing an extradigital glomus tumor is difficult. Recognition of glomus tumors allows for an early diagnosis and resection, and preoperative magnetic resonance imaging helps in the detection of multiple lesions. Before resection, we considered tarsal tunnel syndrome in the differential diagnosis because of the symptoms and location of the tumor. Tarsal tunnel syndrome is a comparatively well-known disease in the foot. When tarsal tunnel syndrome is suspected, a glomus tumor should also be considered in the differential diagnosis.