Electrochemistry in bicontinuous microemulsions derived from two immiscible electrolyte solutions for a membrane-free redox flow battery

HYPOTHESES

Bicontinuous microemulsions (BMEs) have attracted attention as unique heterogeneous mixture for electrochemistry. An interface between two immiscible electrolyte solutions (ITIES) is an electrochemical system that straddles the interface between a saline and an organic solvent with a lipophilic electrolyte. Although most BMEs have been reported with nonpolar oils, such as toluene and fatty acids, it should be possible to construct a sponge-like three-dimensionally expanded ITIES comprising a BME phase.

EXPERIMENTS

Dichloromethane (DCM)-water microemulsions stabilized by a surfactant were investigated in terms of the concentrations of co-surfactants and hydrophilic/lipophilic salts. A Winsor III microemulsion three-layer system, consisting of an upper saline phase, a middle BME phase, and a lower DCM phase, was prepared, and electrochemistry was conducted in each phase.

FINDINGS

We found the conditions for ITIES-BME phases. Regardless of where the three electrodes were placed in the macroscopically heterogeneous three-layer system, electrochemistry was possible, as in a homogeneous electrolyte solution. This indicates that the anodic and cathodic reactions can be divided into two immiscible solution phases. A redox flow battery comprising a three-layer system with a BME as the middle phase was demonstrated, paving the way for applications such as electrolysis synthesis and secondary batteries.

Paraneoplastic Neuromyelitis Optica Spectrum Disorder Related to Glucose-regulated Protein 78 (GRP78) Autoantibodies in a Patient with Lynch Syndrome-associated Colorectal Cancer

Neuromyelitis optica spectrum disorders have been previously reported in a paraneoplastic context, although there is no clear consensus on their pathogenesis. We herein report a case of aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder in a 64-year-old woman with colorectal cancer. She underwent tumor resection, resulting in serum aquaporin-4 antibody titers subsequently becoming negative. Serum samples were also positive for glucose-regulated protein 78 antibody, which has recently been suggested to be a novel factor in the disruption of the blood-brain barrier. Serological and pathological investigations in this case highlight the role and involvement of aquaporin-4 and glucose-regulated protein 78 antibodies in paraneoplastic conditions.

Vertically Oriented Metallic Heterodimer Array Semiembedded in Flat Conductive Carbon Film for Electrochemical Application

General synthesis of a highly oriented metallic heterodimer array based on a selective electrodeposition technique onto a metal nanoparticle-embedded carbon film is proposed, which enables the preparation of heterodimers with a wide variety of metal combinations. This method requires no surfactant, capping agent, organic solvent, or heat treatment. As a representative metal combination, a nickel (Ni)/palladium (Pd) heterodimer array was prepared by selective electrodeposition of Ni nanoparticles (Ni NPs) on top of partially exposed Pd NPs embedded in carbon film electrodes fabricated by a cosputtering technique. Such a selective electrodeposition becomes possible by utilizing the difference in electrodeposition overpotentials between carbon and Pd NP surfaces. X-ray photoelectron spectroscopy revealed a charge transfer from Ni NPs to Pd NPs, implying that the catalytic and optical properties can be expected to be controllable. The formed heterodimer array structure was mechanically stable against ultrasonication in ethanol for over 1 h because most parts of the Pd NPs were tightly embedded in the carbon film. After conversion from Ni to nickel hydroxide (Ni(OH)₂), the electrode showed high electrocatalytic activity toward glucose oxidation, with a higher turnover rate and lower overpotential compared to Ni(OH)₂ electrodeposited on pure carbon film electrodes.

Cardioembolic Stroke Due to Cardiac Sarcoidosis Diagnosed by Pathological Evaluation of the Retrieved Thrombus

A 70-year-old woman undergoing glucocorticoid therapy for cardiac sarcoidosis was brought to our hospital with the sudden onset of right hemiplegia and aphasia. Brain magnetic resonance imaging showed a high diffusion-weighted imaging signal in the left frontotemporal lobe and disruption of blood flow in the M1 segment of the left middle cerebral artery. Hence, she underwent thrombolysis and mechanical thrombectomy, resulting in marked improvement in her neurological symptoms. A pathologic evaluation of the thrombus suggested its cardiogenicity, and the absence of any obvious abnormality other than a left ventricular aneurysm indicated stroke due to a cardioembolic etiology secondary to cardiac sarcoidosis.

Lipophilic Vitamin E Diffusion through Bicontinuous Microemulsions

We studied the diffusion properties of lipophilic vitamin E (VE) through bicontinuous microemulsions (BME) using both electrochemical and fluorescence correlation spectroscopy (FCS) measurements. We investigated the effect of different composition ratios of micro-water and micro-oil phases in BMEs (W/O_BME). When we employed the BME with a lower W/O_BME value of 40/60 (oil-rich BME) as an electrolyte solution, we obtained a larger current response from VE at a fluorinated nanocarbon film electrode. Further voltammetric studies revealed that a higher VE diffusion coefficient was observed in the oil-rich BME. The FCS results also exhibited faster diffusion through the oil-rich BME, which played a significant role in accelerating the VE diffusion probably due to the widening of the micro-oil phase pathway in the BME. Moreover, the effect of increasing the VE diffusion was pronounced at the interface between the electrode surface and the BME solution. These results indicate that controlling the conditions of the BME as the measurement electrolyte is very effective for achieving superior electrochemical measurements in a BME.

Suppression of Surface Oxygen on Nanocarbon Film Electrodes for Maintaining Electrode Activity

We investigated sputtered nanocarbon films with respect to the effect of suppressing surface oxygen on their electrochemical properties. The nanocarbon film consisted of nanocrystallites with mixed sp² and sp³ bonds formed by unbalanced magnetron sputtering. Ultraviolet/ozone (UV/O₃) irradiation and electrochemical pretreatment (ECP) were conducted to change the surface oxygen concentration of nanocarbon film. X-ray photoelectron spectroscopy (XPS) measurements revealed that nanocarbon films with different amounts of surface oxygen could be prepared. In addition, we observed no significant increase of the surface roughness (R_a) at the angstrom level after treatments, owing to a stable structure containing 40% of sp³ bonds. The electrode characteristics, including the potential window and electrochemical properties for some redox species, such as Ru(NH₃)₆^3+/2+, were investigated. Some electrochemical measurements of zinc ions (Zn²⁺) and hydrogen peroxide (H₂O₂) showed that the electrochemical reaction was improved by suppressing the surface oxygen. These results clearly indicated that the low surface oxygen concentration plays an important role in these electrochemical reactions.

Hybrid Carbon Film Electrodes for Electroanalysis

Carbon materials have been widely used for electrochemical analysis and include carbon nanotubes, graphene, and boron-doped diamond electrodes in addition to conventional carbon electrodes, such as those made of glassy carbon and graphite. Of the carbon-based electrodes, carbon film has advantages because it can be fabricated reproducibly and micro- or nanofabricated into electrodes with a wide range of shapes and sizes. Here, we report two categories of hybrid-type carbon film electrodes for mainly electroanalytical applications. The first category consists of carbon films doped or surface terminated with other atoms such as nitrogen, oxygen and fluorine, which can control surface hydrophilicity and lipophilicity or electrocatalytic performance, and are used to detect various electroactive biochemicals. The second category comprises metal nanoparticles embedded in carbon film electrodes fabricated by co-sputtering, which exhibits high electrocatalytic activity for environmental and biological samples including toxic heavy metal ions and clinical sugar markers, which are difficult to detect at pure carbon-based electrodes.

Stand-Alone Semi-Solid-State Electrochemical Systems Based on Bicontinuous Microemulsion Gel Films

Bicontinuous microemulsion (BME)-based hydrogel films were integrated with screen-printed electrodes (SPEs) comprising working, counter, and reference electrodes to form stand-alone, semi-solid-state electrochemical systems that do not require an outer electrolyte solution. The gel network of the BME hydrogel only exists in the microaqueous phase and retains the structure of the entire BME gel. Following gelation, a microaqueous phase with sufficient ionic strength ensured effective ionic conductivity, even in thin gel films. This enabled the electrochemical reaction to proceed using a thin gel film as an electrolyte solution. However, an intact micro-oil phase with no gel network enabled efficient extraction from an external oil solution and exhibited rapid electrochemistry that was comparable to that of a BME solution. Cyclic voltammograms of lipophilic redox species in oil using the gel-integrated SPE system demonstrated successfully in the oil itself and in the air with dropped oil onto the system.

Controlling Surface Oxygen Concentration of a Nanocarbon Film Electrode for Improvement of Target Analytes

A nanocarbon film consisting of nanocrystallites with mixed sp² and sp³ bonds formed by unbalanced magnetron sputtering, was studied with respect to changes in the characteristics caused by the surface oxygen concentration. An electrochemical pretreatment (ECP) was conducted to change the surface oxygen concentration of the nanocarbon film. X-ray photoelectron spectroscopy (XPS) measurements revealed that nanocarbon films with different amounts of surface oxygen could be prepared. In addition, we observed no significant increase of surface roughness (R_a) at the angstrom level after ECP, owing to a stable structure containing 40% of sp³ bonds. The electrode characteristics, including the potential window, and electrochemical properties for some redox species, such as Ru(NH₃)₆^3+/2+, Fe(CN)₆^3-/4- and some biomolecules, were investigated. The anodic potential limit became wider and ΔE_p of Fe(CN)₆^3-/4- became smaller at the treated nanocarbon film electrode than those of the as-deposited nanocarbon film electrode. Based on these results, we realized to measure uridylic acid (UMP) and inosine triphosphate (ITP) with a high oxidation potential by direct oxidation, which was difficult to measure at the as-deposited nanocarbon film electrode.

[Investigation into the Effect of Shitei Extract, a Traditional Chinese Medicine Formulation, on Hiccups]

Hiccups are occasionally experienced by most individuals, and although not life-threatening, they may leadto a decline in quality of life. Shitei extract(shitei, persimmon calyx)may be usedfor the treatment of hiccups. The effects of shitei extract were investigatedin patients admittedto the Japanese RedCross Musashino Hospital between October 2011 andM ay 2016. Numerous prescriptions for shitei extract were reportedin the Department of Respiratory Organs andNeurosurgery. The primary causes of hiccups were chemotherapy andbrain disease. Of 149 patients, 107(71.8%)sufferedfrom hiccups. None of the patients reported adverse events related to the administration of shitei extract. The incidence of hiccups was significantly higher in patients with brain disease(p=0.0075), treatedwith chemotherapy for cancer(p=0.0402), or requiring the insertion of a gastric tube(p=0.0065). Among those treatedwith chemotherapy for cancer, shitei extract was effective against hiccups in 82.0% patients(45 of 55). Furthermore, four patients receivedprophylaxis with shitei extract for the prevention of hiccups after chemotherapy. In conclusion, these results indicate that shitei extract is an effective and safe therapeutic drug for the treatment of hiccups. In particular, shitei extract was effective in the prevention of hiccups after chemotherapy.

Atrial fibrillation type matters: greater infarct volume and worse neurological defects seen in acute cardiogenic cerebral embolism due to persistent or permanent rather than paroxysmal atrial fibrillation

Aims

Some studies have shown that the type of atrial fibrillation (AF), whether paroxysmal AF (PAF) or persistent or permanent AF (PeAF), affects the incidence of ischaemic stroke. This study sought to determine the relationship between the AF pattern and the severity and brain volume of infarction in an AF population including transient ischaemic attack (TIA) patients.

Methods and results

This was a retrospective observational study. We studied 161 consecutive patients who were admitted to our stroke care unit with cardiogenic embolism or TIA related to non-valvular AF (age 79 ± 9.5, 78 females, and 87 PAF patients). We evaluated the differences in severity and infarct volume between the types of AF. Additionally, we divided the patients into three groups according to severe stroke (n = 38), TIA (n = 28), and those who were neither (stroke, n = 95) for the assessment of the predictors of severe stroke and TIA. Persistent or permanent atrial fibrillation patients with acute cardiogenic stroke or TIA had worse peak National Institute of Health Stroke Scale (NIHSS) scores [PAF median 4 (range 3-14), PeAF 17 (5.8-25); P < 0.0001] and worse NIHSS scores at discharge [PAF 2.0 (1-7), PeAF 11 (3-22); P < 0.0001]. Their infarct brain volume assessed by computed tomography or magnetic resonance imaging was also larger [PAF 4.4 (1.1-32) mL, PeAF 64 (6.9-170) mL; P < 0.0001]. Multivariate analysis of severe stroke vs. non-severe stroke patients showed that having PeAF was the only independent predictor of severe stroke [odds ratio (OR) 4.27, 95% confidence interval (CI) 1.91-10.2; P = 0.0003]. Comparison of TIA vs. non-TIA patients showed that PeAF (OR 0.120, 95% CI 0.0230-0.444; P = 0.0008) and anticoagulant use (OR 8.24, 95% CI 2.15-40.8; P = 0.0018) were independent predictors of TIA.

Conclusion

Cardiogenic emboli due to non-valvular PeAF are associated with a worse acute clinical course and greater volume of infarction than those due to PAF.

Electrochemical performance at sputter-deposited nanocarbon film with different surface nitrogen-containing groups

Carbon materials containing nitrogen have been extensively studied as electrode materials for use in non-platinum cathodes of fuel cells due to their high electrocatalytic activity for oxygen reduction. The activity is strongly dependent on the structure of surface nitrogen-containing functional groups. Carbon film containing nitrogen is also suitable for analytical applications because of its low background noise and its electrocatalytic activity, which is superior to that of pure carbon film. Here, we fabricated sputter-deposited nanocarbon film with a nitrogen-containing group and estimated the efficacy of a surface nitrogen-containing group for detecting biomolecules. Two types of carbon films, one rich in graphite-like nitrogen-containing bonds and the other rich in pyridine-like bonds, were successfully fabricated without changing their nitrogen concentration, sp2/sp3 ratio or surface flatness. The carbon film rich in pyridine-like bonds shows a positive oxygen reduction peak of about 250 mV compared with pure carbon film and is also 200 mV more positive compared with film with graphite-like nitrogen-containing bonds. This indicates that pyridine-like bonds contribute more effectively to electrocatalytic activity than graphite-like nitrogen-containing bonds. For detecting biomolecules, carbon film rich in pyridine-like bonds also exhibits more negative peak potentials for the oxidation of NADH and l-ascorbic acid, suggesting that carbon film rich in pyridine-like bonds will show improved performance for detecting electroactive biomolecules.

Increased electrode activity during geosmin oxidation provided by Pt nanoparticle-embedded nanocarbon film

The musty odor compound geosmin was electrochemically detected by using Pt nanoparticle (PtNP)-embedded nanocarbon (Pt-C) films formed with unbalanced magnetron (UBM) co-sputtering. The sputtered Pt components formed NPs (typically 1.53-4.75 nm in diameter) spontaneously in the carbon films, owing to the poor intermiscibility of Pt with carbon. The surface concentrations of PtNPs embedded in the nanocarbon film were widely controllable (Pt = 4.8-35.9 at%) by regulating the target powers of the Pt and carbon individually. The obtained film had a flat surface (Ra = 0.17-0.18 nm) despite the fact the PtNPs were partially exposed at the surface. Compared with a Pt film electrode, some Pt-C films exhibited higher electrode activity against geosmin although the surface Pt concentrations of these Pt-C films were much lower than that of the Pt film electrode, thanks to the wider potential window and lower background current that resulted from the ultraflat and stable carbon-based film prepared by UBM co-sputtering. Computational experiments revealed that the theoretical oxidation potential (Eox) value for geosmin was relatively similar to that obtained in electrochemical experiments using our Pt-C film electrode. Moreover, we also theoretically estimated the possible oxidation site of geosmin molecules and the advantage of the NP shape of the electroactive Pt parts as regards the electrochemical oxidation of geosmin. We successfully used the Pt-C film (10.6 at%) electrode to detect geosmin in combination with HPLC at a low detection limit of 100 ng L-1.

Uneventful Pregnancy and Delivery after Thrombolysis Plus Thrombectomy for Acute Ischemic Stroke: Case Study and Literature Review

BACKGROUND

Intravenous thrombolysis with recombinant tissue plasminogen activator and endovascular mechanical thrombectomy are known to be the most effective treatments in the acute phase of ischemic stroke. However, the safety of intravenous systemic thrombolysis with recombinant tissue plasminogen and endovascular mechanical thrombectomy during pregnancy is not well-confirmed. We describe a case of an uneventful pregnancy and delivery after thrombolysis plus endovascular mechanical thrombectomy for acute ischemic stroke.

MATERIALS AND METHODS

The patient's medical records were reviewed retrospectively. A comprehensive systemic literature search of the PubMed database was conducted.

CASE PRESENTATION

A 36-year-old woman at 21 weeks gestation presented with a sudden headache, dysarthria, and right hemiparesis. Magnetic resonance angiography revealed occlusion of the left internal carotid artery. Recombinant tissue plasminogen activator was administered intravenously 193 minutes after symptom onset, and endovascular mechanical thrombectomy was started immediately. Recanalization of her left internal carotid artery was achieved. The patient continued to experience mild hemiparesis after the initial treatment and started rehabilitation. The fetus remained in satisfactory condition during the pregnancy and was delivered at 38 weeks without obvious maternal or neonatal complications. No apparent abnormality has been observed in the newborn in the first year of life.

CONCLUSIONS

Intravenous recombinant tissue plasminogen and endovascular mechanical thrombectomy could be considered as treatment for acute ischemic stroke during pregnancy unless high risks of hemorrhage or preterm labor are expected.

Association between Delirium and Prehospitalization Medication in Poststroke Patients

PURPOSE

Medication is an important risk factor for delirium; however, the association between delirium and prehospitalization medication is unclear. We investigated the association between prestroke medication and poststroke delirium.

MATERIALS AND METHODS

All patients hospitalized in the stroke care unit from September 2011 to September 2012 were selected, and their delirium symptoms, patient information, and pre- and poststroke medications were analyzed. Delirium was defined as a score of  4 or higher on the Intensive Care Delirium Screening Checklist. Factors that were related to delirium were extracted using univariate analysis, and the independent risk factors were determined using multivariate analysis.

RESULTS

Of the 269 patients analyzed, 97 (36%) experienced delirium. Univariate analysis revealed significant differences between the delirium and nondelirium groups in age, dementia, previous cerebrovascular disease, craniotomy, all insertion-tube types, and 6 categories of prestroke medication. Prestroke polypharmacy was associated with poststroke delirium (P = .002). Multivariate analysis showed that taking antianxiety agents or sleep aids was an independent risk factor for delirium (odds ratio: 3.17, 95% confidence interval: 1.16-8.82).

CONCLUSIONS

The present study suggests that prestroke medication affects the onset of poststroke delirium. These findings can contribute to the prediction and prevention of this condition.

Clinical validity of the Japanese version of WAIS-III short forms: Adaptation for patients with mild neurocognitive disorder and dementia

We investigated the Japanese WAIS-III short form utility in mild neurocognitive disorder and dementia. Our sample consisted of 108 old patients (ages: 65-89; mean age = 78.3). Fifteen short forms (SFs) and full-scale (FS) IQs were compared. The SFs included Dyads (SF1, SF2), Triads (SF3), Tetrads (SF4, SF5, SF6, SF7), Pentad (SF8), Six-subtest (SF9), Seven-subtests (SF10(a)(b), SF11(a)(b), SF12), and Nine-subtest (SF13). Correlations between SFIQs and FSIQ were all significant. Significant differences also were found in paired t-test between FSIQ and 5 SFIQs (SF2: t = -4.16, SF5: t = -7.06, SF7; t = 2.59, SF10(a): t = 2.56, SF12: t = -4.82; p < .05). On the point of clinical accuracy, two SFs led to an appropriate estimated IQ (SF11(a): 84.3%, SF13: 91.7%; within 95% confidence interval and 2 standard error of measurements of FSIQ). However, SF13 was considered to still have a long administration time. The present results suggest that SF11(a) could be the most useful to estimate IQ for Japanese speaking patients with mild neurocognitive disorder and dementia. SF11(a) consists of seven subtests of Similarities, Arithmetic, Digit Span, Information, Picture Completion, Digit Symbol-Coding, and Matrix Reasoning (Ryan & Ward, 1999), and the formula (Axelrod et al., 2001) should be adopted to convert scaled scores into estimated IQ scores.

Serum retinol levels are associated with brain volume loss in patients with multiple sclerosis

Background

Although predicting future brain volume loss (BVL) in patients with multiple sclerosis (MS) is important, studies have shown only a few biomarkers that can predict BVL.

Objectives

The aim of this study is to elucidate the association between longitudinal BVL and serum biomarker candidates.

Methods

This single-center, retrospective, observational study intended to cover MS patients during January 2008 to March 2016. Patients who underwent brain MRI two times at intervals of >24 months and had a blood test to measure biomarker candidates at the time or within three months of the MRI scan were included. Evaluation of brain volume was performed by using SIENAX and SIENA in the FMRIB software library.

Results

Twenty-three patients with MS were included in this study. We found that serum retinol binding protein (RBP) levels were significantly correlated with percentage brain volume change (PBVC) (p = 0.0079). Furthermore, best subset selection of multiple linear regression models identified baseline normalized brain volume and serum RBP as the best predictors of PBVC.

Conclusions

Our study shows that lower serum retinol levels are associated with greater longitudinal BVL and that serum RBP and can be a predictor of BVL.

Depressive disorder may be associated with raphe nuclei lesions in patients with brainstem infarction

BACKGROUND

Depression is a common symptom after stroke, but its neural substrates remain unclear. The ascending serotonergic system originates from the raphe nuclei in the brainstem. We hypothesized that depressive disorder due to brainstem infarction is associated with damage to the raphe nuclei.

METHODS

We prospectively enrolled 19 patients who had the first-ever acute isolated brainstem infarction in an observational cross-sectional study. All patients were evaluated by using the Montgomery Åsberg Depression Rating Scale (MADRS), the clinician-rated version of Apathy Evaluation Scale (AES-C) and Mini-Mental State Examination (MMSE). Depressive disorder was diagnosed according to DSM-5 and MADRS score of 12 or greater. Diffusion tensor imaging and proton density-weighted images were used to identify damage in the raphe nuclei. Accordingly, patients were classified into either the raphe-nuclei-damaged or intact group. Prevalence of depressive disorder and the MADRS, AES-C, and MMSE scores were compared between the two groups.

RESULTS

Depressive disorder was more frequent in the damaged group (n=6) than in the intact group (n=13) (83% vs. 15%; P=0.01). MADRS scores were higher in the damaged group than in the intact group (mean±1 SD, 17.5±7.9 vs. 7.0±4.4; P=0.002), whereas the AES-C and MMSE scores did not differ between groups.

LIMITATIONS

We did not assess the damage to the ascending projection fibers from the raphe nuclei.

CONCLUSIONS

Our results suggest that damage to the raphe nuclei underlies depressive disorder due to brainstem infarction, possibly via serotonergic denervation.

Co-sputter deposited nickel-copper bimetallic nanoalloy embedded carbon films for electrocatalytic biomarker detection

We report the fabrication of a nickel (Ni)-copper (Cu) bimetallic nanoalloy (∼3 nm) embedded carbon film electrode with the unbalanced magnetron (UBM) co-sputtering technique, which requires only a one-step process at room temperature. Most of each nanoalloy body was firmly embedded in a chemically stable carbon matrix with an atomically flat surface (Ra: 0.21 nm), suppressing the aggregation and/or detachment of the nanoalloy from the electrode surface. The nanoalloy size and composition can be controlled simply by individually controlling the target powers of carbon, Ni and Cu, which also makes it possible to localize the nanoalloys near the electrode surface. This electrode exhibited excellent electrocatalytic activity for d-mannitol, which should be detected with a low detection limit in urine samples for the diagnosis of severe intestinal diseases. With a Ni/Cu ratio of around 64/36, the electrocatalytic current per metal area was 3.4 times larger than that of an alloy film electrode with a similar composition (∼70/30). This improved electrocatalytic activity realized higher stability (n = 60, relative standard deviation (RSD): 4.6%) than the alloy film (RSD: 32.2%) as demonstrated by continuous measurements of d-mannitol.

Au Nanoparticle-Embedded Carbon Films for Electrochemical As(3+) Detection with High Sensitivity and Stability

Au nanoparticle (AuNP)-embedded carbon films were formed with a one-step reproducible process by using unbalanced magnetron (UBM) cosputtering to make it possible to detect As(3+) in water. The sputtered Au components formed NPs (typically 5 nm in diameter) spontaneously in the carbon films, owing to the poor intermiscibility of Au with carbon. The surface contents of embedded AuNPs in the carbon film were widely controllable (Au = 13-21 at %) by regulating the target powers of Au and carbon individually. The obtained film had a flat surface (Ra = 0.1 nm) despite the fact the AuNPs were partially exposed at the surface. By anodic stripping voltammetry (ASV) As(3+) detection, a limit of detection of 0.55 ppb and linear dynamic range of 1-100 ppb were obtained with our electrode. These values meet the requirements imposed by international regulation. Moreover, our electrode structure realized good electrode stability for repetitive ASV measurements (relative standard deviation (RSD) = 11.7%, n = 15) because the partially embedded AuNP structures prevented the AuNPs from detaching from the surface. This result was achieved by the electrode recovery only by a potential scan from 0.1 to 1.5 V. Our electrodes can be stocked for a long time (2 years) with maintaining the electrode performance, which is very attractive for practical electrode. Selectivity test by using Tsukuba tap water added 10 ppb As(3+) and 1000 ppb Cu(2+) was successfully achieved with existence of 0.1 M EDTA (RSD = 2.6%, n = 3). The ASV results with tap water samples agreed well with those by the conventional ICPMS method.

Significance of Development and Reversion of Collaterals on MRI in Early Neurologic Improvement and Long-Term Functional Outcome after Intravenous Thrombolysis for Ischemic Stroke

BACKGROUND AND PURPOSE

Predicting response to rtPA is essential in the era of endovascular therapy for stroke. The purpose of this study was to elucidate prognostic factors of early neurologic improvement and long-term outcome with respect to the development and reversion of leptomeningeal collaterals in recanalization therapy after acute ischemic stroke.

MATERIALS AND METHODS

We analyzed consecutive patients with proximal MCA occlusion treated with rtPA from 2007 to 2012 at 2 hospital stroke centers. All patients routinely underwent brain MR imaging before rtPA. To assess the reversion of collateral signs, we included patients who underwent follow-up MR imaging. We assessed the development and reversion of collaterals by using a combination of 2 MR imaging collateral markers, the hyperintense vessel sign and the posterior cerebral artery laterality sign. Early neurologic improvement was defined as a decrease in the NIHSS score of ≥10 or a score of ≤2 at 24 hours of treatment.

RESULTS

Early neurologic improvement was observed in 22 of 48 eligible patients. The development of collaterals at arrival (15/22 versus 9/26, P = .042) was significantly associated with early neurologic improvement. Multivariate analysis adjusting for other variables showed that the development of collaterals at arrival (OR, 4.82; 95% CI, 1.34-19.98; P = .015) was independently associated with early neurologic improvement. Reversion of collaterals was significantly associated with successful recanalization (P < .001), and multivariate analysis showed that the reversion of collaterals was an independent prognostic factor of long-term functional outcome (OR, 5.07; 95% CI, 1.38-22.09; P = .013).

CONCLUSIONS

Our results indicate that the development of leptomeningeal collaterals plays a crucial role in achieving early neurologic improvement, and reversion of collaterals predicts a favorable outcome via arterial recanalization after rtPA treatment for acute stroke.

Spreading of amyotrophic lateral sclerosis lesions--multifocal hits and local propagation?

OBJECTIVE

To investigate whether or not the lesions in sporadic amyotrophic lateral sclerosis (ALS) originate from a single focal onset site and spread contiguously by prion-like cell-to-cell propagation in the rostrocaudal direction along the spinal cord, as has been hypothesised (the 'single seed and simple propagation' hypothesis).

METHODS

Subjects included 36 patients with sporadic ALS and initial symptoms in the bulbar, respiratory or upper limb regions. Abnormal spontaneous activities in needle electromyography (nEMG)-that is, fibrillation potentials, positive sharp waves (Fib/PSWs) or fasciculation potentials (FPs)-were compared among the unilateral muscles innervated by different spinal segments, especially between the T10 and L5 paraspinal muscles, and between the vastus medialis and biceps femoris. Axon length and the proportion of muscle fibre types, which are both related to motoneuronal vulnerability in ALS, are similar in the paired muscles.

RESULTS

Fourteen of 36 patients showed a non-contiguous distribution of nEMG abnormalities from the onset site, with skipping of intermediate segments. In eight of them, the non-contiguous pattern was evident between paired muscles with the same motoneuronal vulnerability. The non-contiguously affected lumbosacral lesions involved motoneuron columns horizontally or radially proximate to one another, appearing to form a cluster in four of the eight patients. FPs, known to precede Fib/PSWs, were shown more frequently than Fib/PSWs in all the lumbosacral segments but L5, suggesting that 2nd hits occur at L5 and then spread to other lumbosacral segments.

CONCLUSIONS

In sporadic ALS, the distribution of lower motoneuron involvement cannot be explained by the 'single seed and simple propagation' hypothesis alone. We propose a 'multifocal hits and local propagation' hypothesis instead.

Cytochrome P450 modified polycrystalline indium tin oxide film as a drug metabolizing electrochemical biosensor with a simple configuration

The development of a biocatalytic electrode consisting of cytochrome P450 (CYP) proteins would be a key technology with which to establish simple drug metabolizing biosensors or screening devices for drug inhibitors. We have successfully detected the direct electron transfer (DET) from a human CYP layer or a CYP microsome adsorbed on a bare indium tin oxide (ITO) film electrode without any modification layers and applied it to drug metabolism evaluation. We compared the electrocatalytic properties of the two ITO films with different surface nanostructures (polycrystalline or amorphous). CYP on polycrystalline ITO film enhanced the electron transfer rate of oxygen reduction about fifteen times more than with amorphous film. The polycrystalline ITO film was a suitable electrode for the adsorption of CYP proteins while maintaining efficient DET and enzymatic activity, probably because of its larger surface area and negatively charged surface. The oxygen reduction current at the polycrystalline ITO film electrodes had increased 3- to 4-fold, specifically coupled with the oxidation of drugs (testosterone and quinidine) by the monooxygenase activity of CYP. In contrast, the oxygen reduction current completely disappeared in the presence of the CYP inhibitor (ketoconazole). Similar results could be obtained from the CYP microsome with sufficiently clear responses. These results indicate that the CYP modified polycrystalline ITO electrode offers the potential for electrochemically evaluating CYP activity for drug metabolism with a simple configuration.