A new species of the genus Pseudocrangonyx (Crustacea: Amphipoda: Pseudocrangonyctidae) from subterranean waters of Japan.

A new species of pseudocrangonyctid amphipod, Pseudocrangonyx asuwaensis, is described from subterranean water in a quarry on Mt. Asuwa "Nanatsuo-guchi", Fukui Prefecture, Japan. Pseudocrangonyx asuwaensis sp. nov. differs from its congeners in various morphological features, such as head without eyes, relative length of antennae 1, female antenna 2 without calceoli, length ratio of mandibular palp articles, setal numbers on maxillae 1 and 2 inner plates, absence of sternal gills, armature of urosomite 1, and shape of telson. Molecular phylogenetic analyses suggest that P. asuwaensis sp. nov. is clustered with P. komaii Tomikawa & Nakano, 2018, Pseudocrangonyx sp. 7 and Pseudocrangonyx sp. 8, and was the first of these species to diverge.

[A Ruptured Vertebral Artery Dissecting Aneurysm Involving the Anterior Spinal Artery:A Case Report].

A 50-year-old woman presented with a subarachnoid hemorrhage caused by a ruptured vertebral artery dissecting aneurysm(VADA)involving the anterior spinal artery(ASA). The ASA branched at the proximal component of the dissecting aneurysm. The rupture point was presumed to be the distal region of the dissecting aneurysm. We performed coil embolization of the distal part only in order to prevent rebleeding and preserve the ASA. The patient showed no neurological deficits. Six months after the procedure, an angiogram demonstrated occlusion of a distal portion of the right vertebral artery. However, the ASA was still patent. No rebleeding occurred, and the patient has remained neurologically symptom-free for 3 years from the treatment. ASA-involved VADAs are extremely rare. Treatment strategy is difficult because there are no options for bypass surgery and occlusion of the ASA may lead to quadriplegia unless there is collateral flow to the ASA. Although the outcome of the patient was good with partial coil embolization in this case, the treatment strategy should be carefully considered for ASA-involved VADAs.

Reappraisal of primary balloon angioplasty without stenting for patients with symptomatic middle cerebral artery stenosis.

There is a controversy regarding the safety and efficacy of intracranial stenting. We describe our experience with primary balloon angioplasty without stenting for symptomatic middle cerebral artery (MCA) stenosis. All patients who underwent balloon angioplasty without stenting for MCA stenosis between 1996 and 2010 were retrospectively reviewed. We evaluated technical success rates, degrees of stenosis, and stroke or death within 30 days. Among patients who were followed-up for > 1 year we evaluated latest functional outcomes, stroke recurrence at 1 year, and restenosis. In total 45/47 patients (95.7%) were successfully treated. Average pre- and postprocedure stenosis rates were 79.9% and 39.5%, respectively. Three neurological complications occurred within 30 days: one thromboembolism during the procedure; one lacunar infarction; and one fatal intraparenchymal hemorrhage after the procedure. Stroke or death rate within 30 days was 6.4%. Thirty-three patients were available for follow-up analysis with a mean period of 51.5 months. The combined rate of stroke or death within 30 days and ipsilateral ischemic stroke of the followed-up patients within 1 year beyond 30 days was 9.4%. Restenosis was observed in 26.9% of patients and all remained asymptomatic. In our retrospective series, balloon angioplasty without stenting was a safe, effective modality for symptomatic MCA stenosis. For patients refractory to medical therapy, primary balloon angioplasty may offer a better supplemental treatment option.

Hemodynamic effects of stent struts versus straightening of vessels in stent-assisted coil embolization for sidewall cerebral aneurysms.

BACKGROUND: Recent clinical studies have shown that recanalization rates are lower in stent-assisted coil embolization than in coiling alone in the treatment of cerebral aneurysms. OBJECTIVE: This study aimed to assess and compare the hemodynamic effect of stent struts and straightening of vessels by stent placement on reducing flow velocity in sidewall aneurysms, with the goal of reducing recanalization rates. METHODS: We evaluated 16 sidewall aneurysms treated with Enterprise stents. We performed computational fluid dynamics simulations using patient-specific geometries before and after treatment, with or without stent struts. RESULTS: Stent placement straightened vessels by a mean (±standard deviation) of 12.9° ± 13.1° 6 months after treatment. Placement of stent struts in the initial vessel geometries reduced flow velocity in aneurysms by 23.1% ± 6.3%. Straightening of vessels without stent struts reduced flow velocity by 9.6% ± 12.6%. Stent struts had significantly stronger effects on reducing flow velocity than straightening (P = 0.004, Wilcoxon test). Deviation of the effects was larger by straightening than by stent struts (P = 0.01, F-test). The combination of stent struts and straightening reduced flow velocity by 32.6% ± 12.2%. There was a trend that larger inflow angles produced a larger reduction in flow velocity by straightening of vessels (P = 0.16). CONCLUSION: In sidewall aneurysms, stent struts have stronger effects (approximately 2 times) on reduction in flow velocity than straightening of vessels. Hemodynamic effects by straightening vary in each case and can be predicted by inflow angles of pre-operative vessel geometry. These results may be useful to design a treatment strategy for reducing recanalization rates.

Retreatment of recanalized aneurysms after Y-stent-assisted coil embolization with double enterprise stents: case report and systematic review of the literature.

It is necessary to consider possibility of recanalization and retreatment after coil embolization for cerebral aneurysms. There is concern that retreatment for recanalized aneurysms after Y-stent-assisted coil embolization may be difficult because of double stents, especially in Y-stents with double closed-cell stents owing to narrowed structures. However, no detailed reports of retreatment after Y-stent have been reported. Between July 2010 and June 2013, we treated four aneurysms with Y-stent-assisted coil embolization using Enterprise closed-cell stents. Recanalization occurred in one case (25%), and retreatment was performed. We easily navigated a microcatheter into the target portions of the aneurysm through the Y-stent and occluded the aneurysm with coils. Additionally, by systematically searching in PubMed, we found 105 cases of Y-stent-assisted coil embolization using Enterprise stents or Neuroform stents with more than 6 months of follow-up. Among them, retreatment was performed in 10 cases (9.5%). There were no significant differences in retreatment rates among different stent combinations (P=0.91; Fisher's exact test). In conclusion, navigation of a microcatheter into the aneurysm through the Y-stent with double Enterprise stents was feasible, and retreatment rates after Y-stent-assisted coiling may not depend on stent combinations.

Non-enhanced magnetic resonance angiography can evaluate restenosis after carotid artery stenting with the Carotid Wallstent.

BACKGROUND: Carotid artery stenting (CAS) requires follow-up imaging to assess in-stent restenosis (ISR). This study aimed to determine whether non-enhanced magnetic resonance angiography (NE-MRA) is useful for evaluating ISR. METHOD: Between 2009 and 2013, we performed 118 consecutive CAS procedures using the Precise stent (n = 78) and the Carotid Wallstent (n = 40). We reviewed 1.5 T NE-MRA and examined visualization of the stent lumen and the degree of ISR if present. Other imaging modalities were used as references. RESULTS: NE-MRA performed just after CAS was not able to visualize the stent lumen in all patients because of metal artifacts. In the Carotid Wallstent group, follow-up NE-MRA was available in 22 patients. The stent lumen was visible more than three months after CAS in all patients. Among them, >40 % ISR was observed by other modalities in eight lesions. The degree of restenosis measured by NE-MRA (y%) had a linear relationship with that measured by conventional angiography (x%) (y = 0.97x-0.4, r = 0.79, P = 0.021). In one case among 17 without ISR (6 %), NE-MRA showed false ISR. In the Precise stent group, NE-MRA did not visualize the stent lumen in the follow-up period. CONCLUSIONS: NE-MRA can visualize the stent lumen in the Carotid Wallstent more than three months after CAS, but not in the Precise stent at follow-up. This delayed visualization might depend on endothelialization of the stent lumen. The degree of ISR measured by NE-MRA is comparable to that by conventional angiography. NE-MRA can evaluate ISR after CAS with the Carotid Wallstent (100 % sensitivity and 94 % specificity).

Stent-assisted coil embolization for cavernous carotid artery aneurysms.

Internal carotid artery (ICA) occlusion with or without a bypass surgery is the traditional treatment for cavernous sinus (CS) aneurysms with cranial nerve (CN) dysfunction. Coil embolization without stents frequently requires retreatment because of the large size of CS aneurysms. We report the mid-term results of six unruptured CS aneurysms treated with stent-assisted coil embolization (SACE). The mean age of the patients was 72 years. The mean size of the aneurysms was 19.8 mm (range: 13-26 mm). Before treatment, four patients presented with CN dysfunction and two patients had no symptoms. SACE was performed under local or general anesthesia in three patients each. Mean packing density was 29.1% and tight packing was achieved. There were no neurological complications. CN dysfunction was cured in three patients (75%) and partly resolved in one patient (25%). Transient new CN dysfunction was observed in two patients (33%). Clinical and imaging follow-up ranged from 6 to 26 months (median: 16 months). Recanalization was observed in three patients (50%; neck remnant in two patients and dome filling in one patient), but no retreatment has yet been required. No recurrence of CN dysfunction has occurred yet. In summary, SACE increases packing density and may reduce requirement of retreatment with an acceptable cure rate of CN dysfunction. SACE may be a superior treatment for coiling without stents and be an alternative treatment of ICA occlusion for selected patients, such as older patients and those who require a high-flow bypass surgery or cannot receive general anesthesia.

Preoperative simulations of endovascular treatment for a cerebral aneurysm using a patient-specific vascular silicone model.

Silicone models of cerebral aneurysms are used for evaluation of devices, training, or hemodynamic studies. We report preoperative simulations of endovascular treatment for a case with an unruptured wide-neck aneurysm of the anterior communicating artery using a patient-specific silicone model. Using a rapid prototyping system, we created a silicone model based on the vascular image obtained by three-dimensional rotational angiogram. The aneurysm and vessels formed a cavity in the silicone block model. We performed endovascular simulations using several difference devices and attempted possible methods for coil embolization. We designed treatment strategies based on the simulations and performed balloon-assisted coil embolization of the aneurysm. The simulations were especially useful in navigation of a microcatheter by planning the shape of its tip beforehand. There was one significant difference between the silicone model simulations and actual treatment: the shape of the vessel in the silicone block model was not changed by insertion of a catheter or guidewire. This is the first study to describe preoperative endovascular simulations using a patient-specific silicone model. Our methods of creating a patient-specific model are relatively simple and easy. Although this is a single case, we demonstrate that the simulations are feasible and helpful for designing a treatment strategy and safe manipulation of endovascular devices by experiencing their behavior before actual treatment.

Triple antiplatelet therapy with addition of cilostazol to aspirin and clopidogrel for Y-stent-assisted coil embolization of cerebral aneurysms.

BACKGROUND: Dual antiplatelet therapy for stent-assisted coiling of cerebral aneurysms is essential to prevent thromboembolic complications. There is concern that Y-stent-assisted coiling may increase thromboembolic complications compared with coiling with a single stent. Several reports have demonstrated that cilostazol may improve clopidogrel responsiveness. We investigated whether triple antiplatelet therapy with addition of cilostazol to aspirin plus clopidogrel for Y-stents can prevent thromboembolic events. METHODS: Between July 2010 and October 2012, we treated 40 consecutive aneurysms with coil embolization using Enterprise stents. At the peri-procedural period, dual antiplatelet agents (100 mg aspirin and 75 mg clopidogrel) were used for the single stent group (n = 36), and triple antiplatelet agents (addition of 200 mg cilostazol) were used for the Y-stent group (n = 4). We evaluated post-operative diffusion-weighted imaging (DWI) and any complications. We assessed the following for statistical analysis: age, sex, aneurysm location, shape, and size, neck size, size of parent vessels, and stent length. RESULTS: We found two neurological peri-procedural complications: one transient ischemic attack and one infarction. Both complications belonged to the Y-stent group, which was a significant factor of thromboembolic events (P = 0.008). There were no other significant factors related to neurological complications or positive DWI. For subgroup analysis of the single stent group, stent length was significantly longer in positive DWI than negative DWI (P = 0.04). In the follow-up period of 20 ± 8.6 months, there were no symptomatic late complications in any patients. CONCLUSIONS: Although the number of patients in the Y-stent group is small, this group had a significantly higher risk of thromboembolic complications. While our protocol of a routine dose of dual antiplatelet therapy may be sufficient for single stent therapy, our protocol of a routine dose of triple antiplatelet therapy for Y-stents may not prevent thromboembolic events. This suggests that evaluation of platelet function may be essential, especially for Y-stents.

Delayed in-stent occlusion due to stent-related changes in vascular geometry after cerebral aneurysm treatment.

Stent-assisted coil embolization has been recently accepted as a treatment option for wide-neck or complex cerebral aneurysms. Delayed in-stent occlusion is described due to stent-related changes in vascular geometry. A 66-year-old man underwent stent-assisted coil embolization for an unruptured aneurysm of the vertebral artery. The treatment was successfully performed using the Enterprise stent. Follow-up angiography at 6 months showed asymptomatic in-stent occlusion. Three-dimensional analysis of the vascular geometry revealed that the left vertebral artery was straightened by 40° due to the stent placement. Such straightening of the vessel presumably caused kinking and occlusion of the vessel. Stent-related changes in vascular geometry may cause kinking of a vessel and result in occlusion after the treatment of cerebral aneurysms. Pre-treatment strategy may avoid this risk.

Stent-assisted coil embolization and computational fluid dynamics simulations of bilateral vertebral artery dissecting aneurysms presenting with subarachnoid hemorrhage: case report.

BACKGROUND AND IMPORTANCE: A vertebral artery dissecting aneurysm (VADA) is a relatively rare cause of subarachnoid hemorrhage. Bilateral VADAs are even rarer, and management strategies are controversial. We report a case of bilateral VADAs presenting with subarachnoid hemorrhage. We treated the patient by stent-assisted coil embolization of both aneurysms at a single session on the basis of results of preoperative computational fluid dynamic simulations. CLINICAL PRESENTATION: A 48-year-old man presented with subarachnoid hemorrhage resulting from bilateral VADAs. We treated the patient by stent-assisted coil embolization of both aneurysms at a single session. Before the treatment, we performed computational fluid dynamics simulations to predict the ruptured side. We also estimated the increase in wall shear stress on an aneurysm in case of trapping of another aneurysm, which might cause enlargement and rupture of the aneurysm. The treatment was performed successfully. The patient remains neurologically intact at 14 months from the onset. CONCLUSION: Stent-assisted coil embolization of subarachnoid hemorrhage with bilateral VADAs for both sides is a reasonable treatment because it prevents rebleeding and preserves bilateral vertebral arteries without increasing hemodynamic stress. To the best of our knowledge, this is the first report to describe this type of treatment for bilateral VADAs with subarachnoid hemorrhage. Computational fluid dynamics simulations may be useful for developing treatment strategies for aneurysms.

Hemodynamic characteristics at the rupture site of cerebral aneurysms: a case study.

BACKGROUND AND IMPORTANCE: Hemodynamics play an important role in the mechanisms of aneurysm formation, growth, and rupture. However, little is known about the hemodynamics of rupture sites. CLINICAL PRESENTATION: We incidentally acquired 3-dimensional images before and at the moment of rebleeding of a cerebral aneurysm in a patient. Comparison of these 2 images enabled precise identification of the rupture site. On the basis of computational fluid dynamics simulation, we propose that there are characteristic hemodynamic parameters of the rupture site in cerebral aneurysms. We evaluated flow velocity, wall shear stress (WSS), pressure, and the oscillatory shear index to determine characteristic parameters at the rupture site. Among the hemodynamic parameters in the cardiac cycle, the rupture site was most markedly distinguished by a combination of low WSS at end diastole and high pressure at peak systole. The flow patterns around the rupture site uniquely changed in the cardiac cycle. The rupture site was an impingement zone at peak systole. Flow separation at the rupture site was observed at end diastole. CONCLUSION: In this case, a region with low WSS at end diastole and high pressure at peak systole was at the rupture site. A possible mechanism of rupture in this particular aneurysm is that low WSS at end diastole caused degeneration and thinning of the aneurysm wall and that high pressure at peak systole (impingement zone) resulted in rupture of the thinning wall.

Endovascular recanalization of the completely occluded internal carotid artery using a flow reversal system at the subacute to chronic stage.

OBJECT: The efficacy and pitfalls of endovascular recanalization were evaluated in cases of internal carotid artery (ICA) occlusion in the subacute to chronic stage. METHODS: Fourteen cases (15 lesions) of symptomatic ICA occlusion with hemodynamic compromise or recurrent symptoms were treated at the subacute to chronic stage using an endovascular technique. The Parodi embolic protection system was used during the recanalization procedure to prevent embolic stroke by reversing the flow from the distal ICA to the common carotid artery. RESULTS: Recanalization of the occluded ICA was possible in 14 of 15 lesions. The occlusion points were 10 cervical ICAs and 4 petrous/cavernous ICAs in successfully recanalized cases. Ischemic symptoms disappeared completely after the treatment, and new ischemic symptoms did not appear related to the treated lesion. Single photon emission computed tomography findings demonstrated the improvement of hemodynamic compromise in all cases. One case showed right middle cerebral artery branch occlusion during the procedure, but this patient's neurological symptoms were stable due to preexisting hemiparesis. Endovascular recanalization was possible and effective in improving hemodynamic compromise. However, there are still several problems with this technique, such as hyperperfusion syndrome after recanalization, cerebral embolism during treatment, durability after treatment, and identification of the occlusion point before treatment. CONCLUSIONS: Endovascular recanalization using an embolic protection device can be considered as an alternative treatment for symptomatic ICA occlusion with hemodynamic compromise or refractoriness to antiplatelet therapy, even in the subacute to chronic stage of the illness.

Generation of dopamine neurons from embryonic stem cells in the presence of the neuralizing activity of bone marrow stromal cells derived from adult mice.

Stromal cell lines such as PA6 and MS5 have been employed for generating dopamine (DA) neurons from embryonic stem (ES) cells. The present study was designed to test whether bone marrow stromal cells (BMSC) derived from adult mice might be available as a feeder layer to produce DA cells efficiently from ES cells. When ES cells were grown on BMSC in the presence of fibroblast growth factor 8 (FGF8) and sonic hedgehog (SHH), about 40% of TuJ1-positive neurons expressed tyrosine hydroxylase (TH). Because these cells labeled with TH were negative for dopamine-beta-hydroxylasae (DBH), the marker for noradrenergic and adrenergic neurons, the TH-positive cells were most likely DA neurons. They indeed expressed midbrain DA neuron markers such as Nurr 1, Ptx-3, and c-ret and were capable of synthesizing and releasing DA in vitro. Furthermore, DA neurons differentiated from ES cells in this differentiation protocol survived transplantation in rats with 6-hydroxydopamine lesions and reversed the lesion-induced circling behavior. The data indicate that BMSC can facilitate an efficient induction of DA neurons from ES cells and that the generated DA neurons are biologically functional both in vitro and in vivo. Insofar as BMSC have recently been employed in autologous cell therapy for ischemic heart and arteriosclerotic limb diseases, the present study raises the possibility that autologous BMSC can be applied in future cell transplantation therapy in Parkinson's disease.

Protection of dopamine neurons by bone marrow stromal cells.

Transplantation of bone marrow stromal cells (BMSC) has recently been demonstrated to provide neuroprotection in animal models of brain injuries such as ischemia and trauma. The present study was undertaken to explore whether BMSC can promote the survival of dopamine (DA) neurons in neuronal insult models in vitro. We also examined whether BMSC can increase the survival rate of embryonic DA neurons grafted into the striatum of a rat model of Parkinson's disease (PD). Treatment with conditioned media derived from BMSC cultures was found to significantly prevent the death of DA neurons in in vitro cell injury models such as serum deprivation and exposure to the neurotoxin 6-OHDA. In a transplantation study, we also found that the survival of grafted DA cells was significantly enhanced by treating donor cells with the conditioned media at the steps of both cell dissociation and implantation. The results suggest that BMSC may secrete diffusible factors able to protect DA neurons against neuronal injuries. Indeed, BMSC expressed mRNA encoding brain-derived neurotrophic factor, fibroblast growth factor-2 and glial cell line-derived neurotrophic factor, all of which have previously been shown to exhibit potent neurotrophic effects on DA cells. Enzyme-linked immunosorbent assay revealed that the cells release these growth factors into culture media. The present data indicate that BMSC may be a potential donor source of cell-based regenerative therapy for PD where the progressive loss of the midbrain DA neurons takes place.

[A case of spontaneous fusiform aneurysm in a middle cerebral artery branch which causes rapidly thrombosed formation in a short period].

A 61-year-old man presented with the complaint of headache. Investigations revealed a fusiform middle cerebral artery aneurysm at the M2 part. The formation of the aneurysm rapidly developed to a partially thrombosed aneurysm in the course of four months. As regards the treatment of the aneurysm, at first we tried surgery with a superficial temporal artery middle cerebral artery bypass (STA-MCA bypass) and trapping of the aneurysm. However, during the procedure, it was difficult to control bleeding from the temporal muscle, bone flap, and subdural space. Because of this, we finished the STA-MCA bypass without trapping of the aneurysm and then, four days later, we confirmed bypass patency and treated the aneurysm using endovascular coil embolization. Based on both surgical and interventional investigations in this case and a review of the reported literature, the authors propose that there are two mechanisms causing the middle cerebral artery fusiform aneurysm to develop thrombosed formation rapidly: (i) Peripheral middle cerebral artery branches demand less blood flow than other major trunk arteries. (ii) Bypass flow maintains perfusion to the distal branches. On the other hand, this flow alteration caused by surgical vascular bypass may promote the development of the aneurysm to thrombosed formation. The treatment of a fusiform middle cerebral artery aneurysm at the M2 part is also discussed.

Intraoperative hemorrhage in medulloblastoma: a case report and review of the literature.

OBJECT: We present the first case of intraoperative hemorrhage in a medulloblastoma. CASE REPORT: A 10-year-old girl presented with a 4-week history of headache, nausea, and vomiting. Radiological examination showed a space-occupying mass in the cerebellar vermis. Surgical removal was performed via a midline suboccipital approach. When the dura was incised and the occipital sinus was ligated after suboccipital craniectomy, bleeding occurred in the tumor. Macroscopically, hematoma was found only in the left part of the tumor and not in the right part. Microscopically, different architectures of tumor vessels, thin-walled and thick-walled, were found between the left part and the right part, respectively. The tumoral contents and hematoma were totally removed. Histological examination revealed a medulloblastoma. CONCLUSION: We experienced a very rare case of medulloblastoma in which intratumoral hemorrhage occurred during operation. We speculate that ligation of the occipital sinus and thin-walled vessels within the tumor might have caused the hemorrhage in our case.