Preparation of pH-Responsive Poly(γ-glutamic acid) Hydrogels by Enzymatic Cross-Linking.

pH-responsive hydrogels are important for oral drug release applications, and they are increasingly demanded to reduce the adverse side effects of drug release and improve drug absorption. In this study, a new type of pH-responsive hydrogel comprised of poly(γ-glutamic acid) modified with tyramine (PGA-Tyr) was developed through enzymatic cross-linking in the presence of horseradish peroxidase (HRP) and hydrogen peroxide (H2O2). The gelation rate, stiffness, swelling behavior, and pore size of the resulting hydrogels were tuned by changing the concentrations of HRP and H2O2 or the degree of substitution (DS) of PGA-Tyr. The pH responsiveness of the hydrogels was evaluated by the swelling ratio in solutions with various pH values, and their pH responsiveness exhibited a good reversibility in pH 2.0 and 7.0 solutions. The degradation rate of the hydrogels in simulated intestinal fluid (SIF) was faster than that in simulated gastric fluid (SGF). Moreover, indomethacin (IM), a hydrophobic drug model, was encapsulated in the hydrogels by rapid in situ gelation, and the pH-dependent drug release of IM-loaded hydrogels was achieved in SGF and SIF. Importantly, when IM was entrapped in pluronic F-127 to form drug micelles, the burst release of the IM-micelle-loaded hydrogels with a high DS of PGA-Tyr was remarkably decreased in SGF, and sustained drug release was presented in SIF. Thus, pH-responsive PGA-based hydrogels have tremendous promise for biomedical applications, especially oral drug delivery.

The Ivy Sign on Fluid Attenuated Inversion Recovery Images Related to Single-Photon Emission Computed Tomography Cerebral Blood Flow in Moyamoya Disease: A Case Report.

Moyamoya disease is an idiopathic progressive cerebrovascular steno-occlusive disorder characterized by the formation of numerous collaterals called Moyamoya vessels. Accurate evaluation of vascular status and cerebral blood flow (CBF) is needed for prompt treatment to prevent ischemic and/or hemorrhagic events. The pathogenesis of the ivy sign on fluid attenuated inversion recovery (FLAIR) images of Moyamoya disease patients is unclear. We report a Moyamoya disease case wherein the ivy sign changed in relation to single-photon emission computed tomography (SPECT)-measured CBF during progression and following treatment. A 49-year-old female presented with slight aphasia and right hemiparesis. Magnetic resonance imaging (MRI) diffusionweighted image revealed cerebral infarction in the left frontal lobe. Cerebral angiography images showed bilateral distal internal carotid artery stenosis and Moyamoya vessels. FLAIR images exhibited the ivy sign. We performed superficial temporal arteryâ€" middle cerebral artery (STA-MCA) bypass surgery with encephalogaleosynangiosis (EGS) and encephalomyosynangiosis (EMS) on the left side 6 months after first presentation. After operation, left-side resting CBF gradually improved on SPECT and the ivy sign decreased. On the other hand, right-side CBF gradually deteriorated at rest, and the ivy sign increased. Therefore, we performed STAâˆ'MCA bypass with EGS and EMS on the right side 4 years after first presentation. After the operation, the resting CBF increased and the ivy sign decreased. The FLAIR ivy sign may be a useful indicator of both deterioration and improvement of CBF status without the need for CBF imaging using contrast material.

The angiotensin II type I receptor antagonist losartan retards amygdala kindling-induced epileptogenesis.

Blood-brain barrier (BBB) breakdown and the subsequent exposure of the cerebral cortex to serum albumin are known to activate transforming growth factor ß (TGF-ß) signaling in astrocytes and to play key roles in epileptogenesis after brain injury. It was recently reported that the angiotensin II type I receptor antagonist losartan suppresses activation of TGF-ß signaling and prevents epileptogenesis in a rat vascular injury model. Here, we investigated the effects of losartan on epileptogenesis following amygdala kindling in rats. Systemic or intracerebroventricular (i.c.v.) administration of losartan significantly delayed the development of severe behavioral seizures and stimulus-induced seizures on EEG (afterdischarge) in the early stage of amygdala kindling, as assessed by electroencephalography. Losartan also significantly increased the number of stimulations required to reach the fully kindled state. However, losartan had no effects on the threshold for afterdischarge induction, the afterdischarge duration, or seizure severity in fully kindled rats. Evaluation of BBB permeability by Evans blue staining did not indicate BBB breakdown (extravasation of serum albumin) in any region of the brain in the fully kindled animals. Thus, losartan may be useful in preventing epileptogenesis, even in post brain-insult epilepsy, in the absence of BBB breakdown.

An intraoperative motor tract positioning method in brain tumor surgery: technical note.

Intraoperative 3D recognition of the motor tract is indispensable to avoiding neural fiber injury in brain tumor surgery. However, precise localization of the tracts is sometimes difficult with conventional mapping methods. Thus, the authors developed a novel brain mapping method that enables the 3D recognition of the motor tract for intrinsic brain tumor surgeries. This technique was performed in 40 consecutive patients with gliomas adjacent to motor tracts that have a risk of intraoperative pyramidal tract damage. Motor tracts were electrically stimulated and identified by a handheld brain-mapping probe, the NY Tract Finder (NYTF). Sixteen-gauge plastic tubes were mounted onto the NYTF and inserted in the estimated direction of the motor tract with reference to navigational information. Only the NYTF was removed, leaving the plastic tubes in their places, immediately after muscle motor evoked potentials were recorded at the minimum stimulation current. Motor tracts were electrically identified in all cases. Three-dimensional information on the position of motor tracts was given by plastic tubes that were neurophysiologically placed. Tips of tubes showed the resection limit during tumor removal. Safe tumor resection with an arbitrary safety margin can be performed by adjusting the length of the plastic tubes. The motor tract positioning method enabled the 3D recognition of the motor tract by surgeons and provided for safe resection of tumors. Tumor resections were performed safely before damaging motor tracts, without any postoperative neurological deterioration.

Serum glucose/potassium ratio as a clinical risk factor for aneurysmal subarachnoid hemorrhage.

OBJECTIVE: Aneurysmal subarachnoid hemorrhage (SAH) can result in poor outcomes, and biomarkers for predicting poor prognosis have not yet been established. The aim of this study was to clarify the significance of the serum glucose/potassium ratio for predicting the prognosis of aneurysmal SAH. METHODS: The authors retrospectively reviewed the records of 565 patients with aneurysmal SAH between 2006 and 2016. The patient group comprised 208 men and 357 women (mean age 61.5 years, range 10-95 years). A statistical analysis was conducted of the clinical and laboratory risk factors of poor outcome, including the serum glucose/potassium ratio. RESULTS: On estimation of the initial assessment using Hunt and Kosnik (H-K) grading, 233 patients (41.2%) were classified as the severe SAH group (H-K Grade IV or V). There were significant correlations between the severe SAH group and serum glucose/potassium ratio (p < 0.0001). Serum glucose/potassium ratio was elevated in an H-K grade-dependent manner (Spearman's r = 0.5374, p < 0.0001). With the estimation of the Glasgow Outcome Scale (GOS) score at discharge, 355 patients (62.8%) were classified as poor outcome (GOS score 1-3). The serum glucose/potassium ratio was elevated in a GOS score at discharge-dependent manner (Spearman's r = 0.4006, p < 0.0001), and was significantly elevated in the poor outcome group compared with the good outcome group (GOS score 4 or 5; p = 0.0245). There were significant correlations between poor outcome and serum glucose/potassium ratio (p < 0.0001), age (p < 0.0001), brain natriuretic peptide levels (p = 0.011), cerebral infarction due to vasospasm (p < 0.0001), and H-K grade (p < 0.0001). Multivariate logistic regression analyses showed significant correlations between poor outcome and serum glucose/potassium ratio (p = 0.009). CONCLUSIONS: In this study, the serum glucose/potassium ratio of patients with aneurysmal SAH at admission was significantly correlated with H-K grade and GOS score at discharge. Therefore, this ratio was useful for predicting prognosis of aneurysmal SAH, especially in severe cases.

Acute Poststroke Depression Is Associated with Thalamic Lesions and Clinical Outcomes: A Case-Control Study.

BACKGROUND: We investigated the role of acute-phase stroke lesions and patient characteristics in poststroke depression (PSD) and its effect on the clinical outcome. PATIENTS AND METHODS: Five and 30 days after admission, 175 patients self-reported their depressive symptoms on the Patient Health Questionnaire-9. We compared the clinical characteristics and outcomes in patients with (n = 41) and without PSD (n = 134). Stroke severity was assessed with the National Institutes of Health Stroke Scale (NIHSS); the modified Rankin Scale (mRS) was used to determine the functional outcome. RESULTS: There was no significant difference between patients with and without PSD in the age, gender ratio, lesion side, and the history of hypertension, diabetes mellitus, alcohol and tobacco use, and previous stroke. Thalamic lesions were significantly associated with PSD (P = .03), although there was no significant difference in both the NIHSS score and the final mRS score of patients with thalamic lesions. Backward stepwise logistic regression analysis showed that a higher NIHSS score and thalamic lesions were independent predictors of PSD. Total hospitalization was significantly longer in patients with PSD. At the time of admission, the NIHSS score was significantly higher in patients who developed moderate to severe PSD than in those with mild PSD or without PSD. CONCLUSIONS: PSD in the acute phase was associated with thalamic lesions and severe stroke. Hospitalization was significantly longer in patients with PSD and their functional disability was more severe, suggesting that PSD played a role in the unsatisfactory results of poststroke rehabilitation.

Intracerebral Hemorrhage Caused by Cerebral Hyperperfusion after Superficial Temporal Artery to Middle Cerebral Artery Bypass for Atherosclerotic Occlusive Cerebrovascular Disease.

Few papers have reported detailed accounts of intracerebral hemorrhage caused by cerebral hyperperfusion after superficial temporal artery to middle cerebral artery bypass (STA-MCA) bypass for atherosclerotic occlusive cerebrovascular disease. We report a case of vasogenic edema and subsequent intracerebral hemorrhage caused by the cerebral hyperperfusion syndrome (CHS) after STA-MCA bypass for atherosclerotic occlusive cerebrovascular disease disease without intense postoperative blood pressure control. A 63-year-old man with repeating left hemiparesis underwent magnetic resonance angiography (MRA), which revealed right internal carotid artery (ICA) occlusion. We performed a double bypass superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery for the M2 and M3 branches. While the patient's postoperative course was relatively uneventful, he suffered generalized convulsions, and computed tomography revealed a low area in the right frontal lobe on Day 4 after surgery. We considered this lesion to be pure vasogenic edema caused by cerebral hyperperfusion after revascularization. Intravenous drip infusion of a free radical scavenger (edaravone) and efforts to reduce systolic blood pressure to <120 mmHg were continued. The patient experienced severe left hemiparesis and disturbance of consciousness on Day 8 after surgery, due to intracerebral hemorrhage in the right frontal lobe at the site of the earlier vasogenic edema. Brain edema associated with cerebral hyperperfusion after STA-MCA bypass for atherosclerotic occlusive cerebrovascular disease should be recognized as a risk factor for intracerebral hemorrhage. The development of brain edema associated with CHS after STA-MCA bypass for atherosclerotic occlusive cerebrovascular disease requires not only intensive control of blood pressure, but also consideration of sedation therapy with propofol.

Quantitative Comparison of the Intraoperative Utility of Indocyanine Green and Fluorescein Videoangiographies in Cerebrovascular Surgery.

BACKGROUND: A quantitative analysis comparing indocyanine green videoangiography (ICG-VAG) and fluorescein videoangiography (FL-VAG) in cerebrovascular surgery has not been reported so far. OBJECTIVE: To clear the differences of characteristics of ICG-VAG and FL-VAG by quantitative assessment. METHODS: We prospectively analyzed results from 23 patients (3 males; mean age at surgery: 60.9 years, range: 14-75 years) at our hospital from August 2014 to July 2015. Eighteen patients had cerebral aneurysms for clipping, and 5 had intracranial arterial stenosis for superficial temporal artery (STA)-middle cerebral artery bypass. We imported data from the operative image data, converted by Audio Video Interleave to Aquacosmos as picture fluorescence intensity-analyzing software. Regions of interest were set at the parent artery, dome of aneurysms, and perforating artery in cases of clipping of aneurysms, and setting at 3 points in STA, in case of bypass. The transition of fluorescence intensity at each region of interest was calculated and plotted using Aquacosmos. RESULTS: Thick-walled artery, such as parent artery ( P = .0017) and STA ( P = .0182), was more significantly visualized by ICG-VAG than FL-VAG, whereas the perforating artery, especially in deep surgical fields, such as anterior communicating artery, internal carotid artery, and basilar artery, was better visualized by FL-VAG than ICG-VAG ( P < .0001). CONCLUSION: In this quantitative analysis of fluorescence study, ICG-VAG showed greater efficacy than FL-VAG in visualizing relatively thick arteries, such as parent artery and STA. However, FL-VAG has greater efficacy than ICG-VAG in visualizing perforating artery, especially in deep surgical fields with characteristic vessel walls.

Adenosine A1 receptors measured with 11 C-MPDX PET in early Parkinson's disease.

Adenosine A1 receptors (A1 Rs) interact negatively with dopamine D1 receptors (D1 Rs) in neurons of the basal ganglia's direct pathway, while adenosine A2A receptors (A2A Rs) negatively interact with dopamine D2 receptors (D2 Rs) in indirect-pathway neurons. The aim of this study was to investigate the cerebral density of A1 Rs in Parkinson's disease (PD) in its early stages, using PET scans with the radioligand 8-dicyclopropylmethyl-1-11 C-methyl-3-propylxanthine (11 C-MPDX). We studied 10 drug-naïve patients with early PD. Each patient was also examined for dopamine transporters (DATs) and D2 Rs by PET using 11 C-2-ß-carbomethoxy-3-ß-(4-fluorophenyl)-tropane (11 C-CFT) and 11 C-raclopride (11 C-RAC), respectively. Ten elderly, healthy volunteers were recruited as controls for 11 C-MPDX PET scanning and eight elderly volunteers were recruited as controls for 11 C-CFT and 11 C-RAC PET scanning. The PET scans revealed a decrease in the uptake ratio index (URI) of 11 C-CFT and an increase in the URI of 11 C-RAC in patients. In the temporal lobe, the binding potential for 11 C-MPDX was higher in the patient group than in healthy subjects, but not in the other regions examined, including the striatum. In patients, we observed motor-symptom asymmetry and a relationship between parkinsonism and the striatal density of DATs, but not A1 R density. In the putamen of early PD, asymmetrical down-regulation of A2A Rs is likely a compensatory mechanism in response to a decrease in dopamine. However, our study suggests that A1 Rs are unaltered in the putamen of early PD.

Environmental and Clinical Risk Factors for Delirium in a Neurosurgical Center: A Prospective Study.

BACKGROUND: Few reports of delirium-related risk factors have focused on environmental risk factors and clinical risk factors, such as white matter signal abnormalities on magnetic resonance imaging fluid attenuated inversion recovery images. METHODS: We prospectively enrolled 253 patients admitted to our neurosurgical center between December 2014 and June 2015 and analyzed 220 patients (100 male patients; mean age, 64.1 years; age range, 17-92 years). An Intensive Care Delirium Screening Checklist score ≥4 points indicated delirium. We evaluated patient factors consisting of baseline characteristics and related factors, such as white matter lesions (WMLs), as well as the surrounding environment. RESULTS: Delirium occurred in 29/220 cases (13.2%). Regarding baseline characteristics, there were significant statistical correlations between delirium and age (P = 0.0187), Hasegawa Dementia Scale-Revised score (P = 0.0022) on admission, and WMLs (P < 0.0001). WMLs were related to age (P < 0.0001) and atherosclerotic disease (P = 0.004). Regarding related factors, there were significant statistical correlations between delirium and stay in a neurosurgical care unit (P = 0.0245). Multivariate logistic regression analyses showed statistically significant correlations of delirium with WMLs (P < 0.0001) and surrounding patients with delirium (P = 0.026). CONCLUSIONS: WMLs in patients and the surrounding environment are risk factors for delirium in a neurosurgical center. To prevent delirium, clinicians must recognize risk factors, such as high-grade WMLs, and manage environmental factors.

Superior Cluneal Nerve Entrapment Neuropathy and Gluteus Medius Muscle Pain: Their Effect on Very Old Patients with Low Back Pain.

OBJECTIVE: In the very elderly, their general condition and poor compliance with drug regimens can render the treatment of low back pain (LBP) difficult. We report the effectiveness of a less-invasive treatment for intractable LBP from superior cluneal nerve entrapment neuropathy (SCN-EN) and gluteus medius muscle (GMeM) pain. PATIENTS AND METHODS: Between April 2013 and March 2015, we treated 17 consecutive elders with LBP, buttock pain, and leg pain. They were 4 men and 13 women ranging in age from 85 to 91 years (mean 86.6 years). We carefully ascertained that their symptoms were attributable to SCN-EN and GMeM pain. The median follow-up period was 21.5 ± 12.2 months (range 2-35 months). RESULTS: SCN-EN was diagnosed in 15 patients (28 sites) and GMeM pain in 14 (27 sites). In 5 patients, we obtained symptom control by local block (Numerical Rating Scale for LBP: declined from 7.8 to 0.8 [P < 0.05], Roland-Morris Disability Questionnaire score: declined from 16.5 to 5.2). The other 12 were operated under local anesthesia (SCN neurolysis, GMeM decompression). As 3 patients reported the persistence of leg pain postoperatively, they subsequently underwent peroneal nerve neurolysis and surgery for tarsal tunnel syndrome. These treatments resulted in significantly symptom abatement (Numerical Rating Scale: from 8.2 to 1.7, Roland-Morris Disability Questionnaire score: from 12.8 to 8.6; P < 0.05). CONCLUSIONS: Even very old patients with intractable LBP, buttock pain, and leg pain due to SCN-EN or GMeM pain can be treated successfully by peripheral block and less-invasive surgery under local anesthesia.

Retrograde suction decompression of a large internal carotid aneurysm using a balloon guide catheter combined with a blood-returning circuit and STA-MCA bypass: a technical note.

It is difficult to treat large internal carotid aneurysms with simple surgical clipping. Here, we present a retrograde suction decompression (RSD) procedure for large internal carotid aneurysms using a balloon guide catheter combined with a blood-returning circuit and a superficial temporal artery to middle cerebral artery (STA-MCA) bypass.All patients underwent an STA-MCA bypass before the temporary occlusion of the internal carotid artery (ICA). A 6-French sheath was inserted into the common carotid artery (CCA), and a 6-French Patrive balloon catheter was placed into the ICA 5 cm past the bifurcation. Aneurysm exposure was obtained; temporary clips were placed on the proximal M1, A1, and posterior communicating (Pcom) segments; and an extension tube was then connected to the balloon catheter. A three-way stopcock was placed, and aspiration was performed through the device to collapse the aneurysm. The aspirated blood was returned to a venous line with an added heparin to prevent anemia after aspiration. During the decompression, the blood flow to the cortical area was supplied through the STA-MCA bypass. After the aneurysm collapse, the surgeon carefully dissected the perforating artery from the aneurysm dome or neck, and permanent clips were then placed on the aneurysm neck. Our procedure has several advantages, such as STA-MCA bypass without external carotid artery occlusion for preventing ischemic complications of the cortical area, anemia may be avoided because of the return of the aspirated blood, and a hybrid operation room is not required to perform this method.

Recovery of Visual and Ophthalmologic Symptoms After Treating Large or Giant Internal Carotid Artery Aneurysm by High-Flow Bypass with Cervical Ligation.

OBJECTIVE: Large or giant internal carotid artery (ICA) aneurysms often cause visual deficits and cranial nerve palsy. The aim of this study was to investigate the efficacy of ligation of the ICA with high-flow bypass. METHODS: We retrospectively analyzed the findings from patients with visual deficit and ophthalmologic symptoms due to ICA aneurysms. In addition, we analyzed the recovery factors associated with the visual deficit and ophthalmologic symptoms postoperatively, focusing on the type of cranial nerve palsy, aneurysm size, location, and the time to treatment from first symptoms. RESULTS: We identified 38 patients (35 women, 3 men) with a mean age at surgery of 63.6 years (range, 24-81 years) with visual and ophthalmologic symptoms due to large or giant internal carotid aneurysm. Aneurysms ranged in size from 15-50 mm (mean, 25.2 mm). Visual disturbance (7 cases, 18%) and ophthalmoplegia (31 cases, 82%) were the only preoperative cranial nerve palsies. Aneurysms were completely thrombosed in 94.7% of cases (36/38). Visual disturbance improved in 28.5% of cases (2/7), and ophthalmoplegia improved in 87.1% of cases (27/31). Time to therapy from developing a visual disturbance was longer than time to therapy from developing ophthalmoplegia (P = 0.001). Time to therapy was significantly associated with recovery from cranial nerve palsy (P < 0.0001). The recovery of visual disturbance was worse than that of ophthalmoplegia (P = 0.001). CONCLUSION: Early treatment is recommended when the visual and ophthalmologic symptoms are present because treatment delay is a risk factor for nonimprovement of symptoms.

The Impact of Tarsal Tunnel Syndrome on Cold Sensation in the Pedal Extremities.

OBJECTIVE: Tarsal tunnel syndrome (TTS) is an entrapment neuropathy of the posterior tibial nerve in the tarsal tunnel. It is not known whether vascular or neuropathic factors are implicated in the cause of a cold sensation experienced by patients. Therefore, we studied the cold sensation in the pedal extremities of patients who did or did not undergo TTS surgery. METHODS: Our study population comprised 20 patients with TTS (38 feet); 1 foot was affected in 2 patients and both feet in 18 patients. We acquired the toe-brachial pressure index to evaluate perfusion of the sole and toe perfusion under 4 conditions: the at-rest position (condition 1); the at-rest position with compression of the foot dorsal artery (condition 2); the Kinoshita foot position (condition 3); and the Kinoshita foot position with foot dorsal artery compression (condition 4). Patients who reported abatement in the cold sensation during surgery underwent intraoperative reocclusion of the tibial artery to check for the return of the cold sensation. RESULTS: The toe-brachial pressure index for conditions 1 and 3 averaged 0.82 ± 0.09 and 0.81 ± 0.11, respectively; for conditions 2 and 4, it averaged 0.70 ± 0.11 and 0.71 ± 0.09, respectively. Among the 16 operated patients, the cold sensation in 7 feet improved intraoperatively; transient reocclusion of the tibial artery did not result in the reappearance of the cold sensation. CONCLUSIONS: Our findings suggest that the cold sensation in the feet of our patients with TTS was associated with neuropathic rather than vascular factors.

[Prospective Study of the Causes of Limb Numbness in Patients with Diabetes].

PURPOSE: Many patients with diabetes mellitus (DM) experience numbness in the extremities. This DM neuropathy may be complicated by peripheral entrapment neuropathy. We prospectively investigated the cause(s) of limb numbness in DM patients. MATERIALS AND METHODS: We enrolled 23 patients with uni- or bilateral limb numbness who were treated in our DM clinic. They were 10 men and 13 women; their average age was 63 years. The average duration of their neurological symptoms was 28.3 months. RESULTS: Numbness was located in the upper limb in 7 patients, the lower limb in 11, and both the upper and lower limbs in 5. Among the 12 patients with upper-limb numbness, 9 manifested carpal tunnel syndrome and one each cervical OPLL or cervical spondylosis. Of the 16 cases of lower limb numbness, 10 were attributable to tarsal tunnel syndrome, 7 to lumbar spinal disease, 3 to restless leg syndrome, 2 to piriformis syndrome, and 1 to peroneal nerve entrapment neuropathy. CONCLUSIONS: In 21 of the 23 patients with uni- or bilateral limb numbness, the cause was attributable to several kinds of etiology such as entrapment neuropathy. Consequently, other treatable peripheral nerve disorders, e.g. tarsal tunnel syndrome, must be considered when diagnosing DM patients with limb numbness. Our findings suggest that therapeutic intervention to address such diseases will affect the quality of life of DM patients with limb numbness.

Intraoperative middle cerebral artery pressure measurements during superficial temporal artery to middle cerebral artery bypass procedures in patients with cerebral atherosclerotic disease.

OBJECTIVE No previous study has monitored middle cerebral artery (MCA) pressure during the superficial temporal artery (STA)-MCA bypass procedure for cerebral atherosclerotic disease. In this paper, the authors describe their method of monitoring MCA pressure and report their initial data on intraoperative MCA pressure and its relationship with hemodynamics prior to and after the bypass procedures. METHODS The results from a total of 39 revascularization procedures performed between 2004 and 2014 were analyzed. The patient group included 27 men and 12 women, and their mean age at surgery was 67.6 years (range 39-83 years). The authors investigated the MCA pressure via the STA during STA-MCA bypass procedures. After one branch of the STA was anastomosed to the MCA, the other branch was connected to an arterial line, and a clip was placed temporally on the main STA trunk to monitor the pre-anastomosis MCA pressure. Simultaneously, the radial artery (RA) pressure was determined before removing the temporal clip to measure the post-anastomosis MCA pressure. The relationship between MCA pressures and single photon emission computed tomography findings and the risk factors for hyperperfusion after STA-MCA bypass were analyzed. RESULTS The MCA/RA (%) pressure was significantly correlated with that of the resting stenotic/normal side cerebral blood flow (CBF) ratio (%) in the linear regression analysis (slope 1.200, r2 = 0.3564, F = 20.49, p < 0.0001). The intraoperative MCA pressure was 39.3% of RA pressure in patients with Powers' Stage 2 cerebral atherosclerotic disease. After 1 branch of the STA was anastomosed, the intraoperative MCA pressure increased to 75.3% of the RA pressure. The rate of increase in pressure was significantly correlated with the increase in the STA diameter in the linear regression analysis (slope 2.59, r2 = 0.205, F = 9.549, p = 0.0038). Hyperperfusion occurred in 2 cases. When mean values for these 2 patients were compared with those for the 37 patients without hyperperfusion, significant differences were found in the stenotic/normal side CBF ratio (p = 0.0001), pre-anastomosis MCA pressure (p = 0.02), rate of increase in pressure (p = 0.02), pre-anastomotic MCA/RA pressure ratio (p = 0.01), vascular reserve (p = 0.0489), and STA diameter (p = 0.0002). CONCLUSIONS The measurement of intraoperative MCA pressure may be a useful technique to assess cerebral perfusion and for predicting the risk of hyperperfusion. Monitoring MCA pressure is recommended during STA-MCA bypass procedures for atherosclerotic disease.

Protection Device Made of a Modified Syringe for Muscle Protection During Cranial Perforation: Technical Note.

In neurosurgical procedures, avoiding damage of surrounding tissues such as muscle and periosteum during a craniotomy is important for esthetic and other reasons. We devised a protection tool by using an amputated syringe barrel to cover the perforating drill and protect temporal muscle damage. This device made it possible to prevent damage to surrounding tissues, such as the muscle and periosteum, during cranial perforation. This method could be useful as it is cost-effective, simple, and versatile.

Enzymes as Green Catalysts for Precision Macromolecular Synthesis.

The present article comprehensively reviews the macromolecular synthesis using enzymes as catalysts. Among the six main classes of enzymes, the three classes, oxidoreductases, transferases, and hydrolases, have been employed as catalysts for the in vitro macromolecular synthesis and modification reactions. Appropriate design of reaction including monomer and enzyme catalyst produces macromolecules with precisely controlled structure, similarly as in vivo enzymatic reactions. The reaction controls the product structure with respect to substrate selectivity, chemo-selectivity, regio-selectivity, stereoselectivity, and choro-selectivity. Oxidoreductases catalyze various oxidation polymerizations of aromatic compounds as well as vinyl polymerizations. Transferases are effective catalysts for producing polysaccharide having a variety of structure and polyesters. Hydrolases catalyzing the bond-cleaving of macromolecules in vivo, catalyze the reverse reaction for bond forming in vitro to give various polysaccharides and functionalized polyesters. The enzymatic polymerizations allowed the first in vitro synthesis of natural polysaccharides having complicated structures like cellulose, amylose, xylan, chitin, hyaluronan, and chondroitin. These polymerizations are "green" with several respects; nontoxicity of enzyme, high catalyst efficiency, selective reactions under mild conditions using green solvents and renewable starting materials, and producing minimal byproducts. Thus, the enzymatic polymerization is desirable for the environment and contributes to "green polymer chemistry" for maintaining sustainable society.

The meningeal branches of the superior cerebellar artery: a surgical observation study.

OBJECT The tentorial branch of the posterior cerebral artery was first identified in a cadaver dissection study. However, the tentorial branch of the superior cerebellar artery (SCA) has not been clearly described in autopsy or normal anatomical studies. In this study, a dural branch of the SCA that was found during the surgical treatment of trigeminal neuralgia is described. METHODS Between April 2011 and March 2014, 70 patients with idiopathic trigeminal neuralgia underwent microvascular decompression. The records of 58 patients were reviewed to investigate the meningeal branch of the SCA. RESULTS The meningeal branch of the SCA was visualized in 15 of the 58 patients (25.9%). In 4 patients, it was necessary to divide this branch in order to achieve decompression of the trigeminal nerve without eliciting postoperative neurological deficits. CONCLUSIONS This is the first identification of the meningeal branch of the SCA in living subjects, and such branches were rather frequently found. Recognition of this branch is important for the management of lesions in the cerebellopontine angle and tentorial lesions, using either an open microsurgical or endovascular method.

Olfactory preservation during anterior interhemispheric approach for anterior skull base lesions: technical note.

Anosmia is not a rare complication of surgeries that employ the anterior interhemispheric approach. Here, we present a fibrin-gelatin fixation method that provides reinforcement and moisture to help preserve the olfactory nerve when using the anterior interhemispheric approach and describe the results and outcomes of this technique. We analyze the outcomes with this technique in 45 patients who undergo surgery for aneurysms, brain tumors, or other pathologies via the anterior interhemispheric approach. Anosmia occurred in 4 patients (8.8%); it was transient in 2 (4.4%) and permanent in the remaining 2 (4.4%). Brain tumors clearly attached to the olfactory nerve were resected in the patients with permanent anosmia. We found a significant difference in the presence of anosmia between patients with or without lesions that were attaching the olfactory nerve (p = 0.011). Our results suggested that fibrin-gelatin fixation method can reduce the reported risk of anosmia. However, the possibility of olfactory nerve damage is relatively high when operating on brain tumors attaching olfactory nerve.