Ketamine as an Alternative Anesthetic for Augmenting Seizure Durations During Electroconvulsive Therapy : A Retrospective Observational Study

Objective: Electroconvulsive therapy (ECT) is highly effective for severe psychiatric disorders; however, short seizure durations may lead to ineffective therapy. This retrospective study aimed to examine the risks and benefits of switching to ketamine anesthesia to augment seizure durations during an acute course of ECT. Methods: We included 33 patients who underwent ketamine anesthesia due to suboptimal seizures during an acute course of ECT. We assessed seizure duration, stimulus dose, hemodynamic variability, and post-seizure complications before and after switching to ketamine. Results: Age was significantly associated with suboptimal seizures during ECT (p = 0.040). After switching to ketamine, 32 patients (97%) experienced prolonged seizure duration. Ketamine significantly prolonged both electroencephalogram and motor seizure durations with a mean difference of 34.6 s (95% CI, 26.4 to 42.7; p < 0.001) and 26.6 s (95% CI, 19.6 to 33.6; p < 0.001), respectively. It also significantly reduced stimulus dose (mean difference: −209.5 mC [95% CI, −244.9 to −174.1], p < 0.001). Additionally, maximum changes in systolic blood pressure and heart rate during ECT sessions significantly increased with ketamine (mean difference: 27.2 mmHg [95% CI, 12.0 to 42.4; p = 0.001]; 25.7 bpm [95% CI, 14.5 to 36.8; p < 0.001], respectively). Patients reported more headaches with ketamine (p = 0.041). Conclusions: Our results provide evidence that ketamine as an alternative anesthetic can augment seizure durations in specific patients experiencing suboptimal seizures during an acute course of ECT. However, its use requires greater attention to circulatory management and post-seizure complications

Fluorescence modulation by fast photochromism of a [2.2]paracyclophane-bridged imidazole dimer possessing a perylene bisimide moiety

© 2018 The Royal Society of Chemistry. The development of single-molecule imaging and super-resolution microscopy techniques has promoted the study of fluorescence switchable molecules that have been important for the in-depth understanding of the activities of organelles and the geometries of materials in the nano- and microscale. The utilization of photochromic compounds as the photo-switching trigger is an efficient strategy to reversibly control the fluorescent "ON" and "OFF" states. In this study, we demonstrated the red-color fluorescence switching of a perylene bisimide (PBI) derivative by using a fast photochromic [2.2]paracyclophane-bridged imidazole dimer. The transient colored biradical species as the fluorescence quencher is generated upon UV light irradiation. Because the biradical species has broad absorption bands in the whole visible light and the near-infrared regions (500-900 nm), the fluorescence of PBI could be efficiently quenched by Förster resonance energy transfer (FRET). The fluorescence intensity was switched by means of fast photochromic cycles within a few tens of milliseconds. The potential capability of the transient biradical species to switch the fluorescence in the visible and NIR regions will open up new possibilities in multicolor fluorescence imaging.status: publishe

Rapid Fluorescence Switching by Using a Fast Photochromic [2.2]Paracyclophane-Bridged Imidazole Dimer

Recently, we have developed a series of fast photochromic imidazole dimers with a [2.2]­paracyclophane ([2.2]­PC) moiety that bridge diphenylimidazole units and succeeded the acceleration of the thermal decoloration rate. The colorless [2.2]­PC-bridged imidazole dimers show a photoinduced homolytic bond cleavage of the C–N bond between the imidazole rings to give a pair of colored imidazolyl radicals upon UV light irradiation, followed by the radical–radical coupling reaction to form the initial C–N bond between the imidazole rings. The decoloration reaction to give the initial imidazole dimer proceeds only thermally. The high quantum yield close to unity of the photochromic reaction and the large extinction coefficient of the radical achieve both high optical density at the photostationary state and rapid switching speed. The application to rapid fluorescence switching has been investigated to develop a new type of photochromic fluorescence switching molecule applicable to super-resolution microscopy. The widespread absorption of the colored radical lying between 500 and 900 nm enables the efficient quenching of the excited electronic state of the fluorophores by Förster resonance energy transfer (FRET) from the fluorophores to the radical moiety. We successfully developed a [2.2]­PC-bridged imidazole dimer possessing a fluorescein moiety as a fluorescence unit. This photochromic dye shows fast photochromism to give a pair of imidazolyl radicals that quench the fluorescence from the fluorescent unit by the FRET mechanism. The fluorescence intensity can be switched rapidly with the fast photochromism

Rapid Fluorescence Switching by Using a Fast Photochromic [2.2]Paracyclophane-Bridged Imidazole Dimer

Recently, we have developed a series of fast photochromic imidazole dimers with a [2.2]­paracyclophane ([2.2]­PC) moiety that bridge diphenylimidazole units and succeeded the acceleration of the thermal decoloration rate. The colorless [2.2]­PC-bridged imidazole dimers show a photoinduced homolytic bond cleavage of the C–N bond between the imidazole rings to give a pair of colored imidazolyl radicals upon UV light irradiation, followed by the radical–radical coupling reaction to form the initial C–N bond between the imidazole rings. The decoloration reaction to give the initial imidazole dimer proceeds only thermally. The high quantum yield close to unity of the photochromic reaction and the large extinction coefficient of the radical achieve both high optical density at the photostationary state and rapid switching speed. The application to rapid fluorescence switching has been investigated to develop a new type of photochromic fluorescence switching molecule applicable to super-resolution microscopy. The widespread absorption of the colored radical lying between 500 and 900 nm enables the efficient quenching of the excited electronic state of the fluorophores by Förster resonance energy transfer (FRET) from the fluorophores to the radical moiety. We successfully developed a [2.2]­PC-bridged imidazole dimer possessing a fluorescein moiety as a fluorescence unit. This photochromic dye shows fast photochromism to give a pair of imidazolyl radicals that quench the fluorescence from the fluorescent unit by the FRET mechanism. The fluorescence intensity can be switched rapidly with the fast photochromism

The Safety and Strategies for Reinitiating Electroconvulsive Therapy (ECT) After ECT-Induced Takotsubo Cardiomyopathy : A Case Report and Systematic Review

Objectives: Takotsubo cardiomyopathy (TCM) is a life-threatening complication of electroconvulsive therapy (ECT). We report the case of a 66-year-old woman who was re-challenged with ECT after ECT-induced TCM. Moreover, we have made a systematic review to assess the safety of and strategies for re-initiating ECT after TCM. Methods: We searched for published reports on ECT-induced TCM since 1990 in MEDLINE (PubMed), Scopus, Cochrane Library, ICHUSHI, and CiNii Research. Results: A total of 24 ECT-induced TCM cases were identified. Patients who developed ECT-induced TCM were predominantly middle-aged and older women. There was no specific trend in anesthetic agents used. Seventeen (70.8%) cases developed TCM by the third session in the acute ECT course. Eight (33.3%) cases developed ECT-induced TCM despite the use of β-blockers. Ten (41.7%) cases developed cardiogenic shock or abnormal vital signs related to cardiogenic shock. All cases recovered from TCM. Eight (33.3%) cases tried to receive ECT retrial. The duration until ECT retrial was between 3 weeks and 9 months. The most common preventive measures during ECT retrial were related to β-blockers; however, the type, dose, and route of administration of β-blockers varied. In all cases, ECT could be re-performed without TCM recurrence. Conclusions: ECT-induced TCM is more likely to cause cardiogenic shock than non-perioperative cases; nevertheless, it has good prognosis. Cautious re-initiation of ECT after TCM recovery is possible. Further studies are required to determine preventive measures for ECT-induced TCM

Fast Photochromism Involving Thermally-Activated Valence Isomerization of Phenoxyl-Imidazolyl Radical Complex Derivatives

Open-shell biradicals have received considerable attention in material science because of their high two-photon absorption cross sections and broad and high absorptive features over the visible region. However, the instability of the biradical caused by the open-shell nature was one of the drawbacks; therefore, novel radical compounds which can suppress unwanted reactions by tuning the open-shell features are desired to expand the versatility of the radical compounds. Here, we report a novel radical-dissociation-type photochromic compound whose photochromic reaction involves a valence isomerization from the open-shell biradical to closed-shell quinoidal forms by using a phenoxyl-imidazolyl radical complex framework. The valence isomerization from the biradical to quinoid forms effectively tunes the open-shell feature in time and drastically changes the spectral features, which were revealed by time-resolved Fourier transform infrared spectroscopy. This novel fast photochromic property not only is important for fundamental spin chemistry but also expands the versatility of the radical compounds for novel advanced photofunctional materials

Electrochemistry of Photochromic [2.2]Paracyclophane-Bridged Imidazole Dimers: Rational Understanding of the Electronic Structures

[2.2]­Paracyclophane-bridged imidazole dimers, which show unique fast photochromism, have various practical applications in industry. To put them to practical use, it is necessary to prepare various types of the imidazole dimers which have different color, reaction rate, sensitivity, etc. One of the simple methods for modulating the optical properties is to add substituents and sensitizers. However, it is difficult to estimate the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of the imidazole dimers by optical spectroscopy because the LUMO of the imidazole dimers are optically inactive. In the present study, we applied electrochemistry and density functional theory to reveal the effect of substituents on the electronic states of the imidazole dimers. We revealed that the HOMO and LUMO of the imidazole dimers are localized over only one of the imidazole rings of the imidazole dimer. By comparing the measured LUMO energies of the imidazole dimers and calculated LUMO energies of several visible sensitizers, we found which visible sensitizers work in the imidazole dimer systems. These fundamental insights provide useful information for understanding the electronic structures of the imidazole dimers and give a strategy for designing novel fast photochromic molecules whose photochromism is triggered by visible light

Fast Photochromism Involving Thermally-Activated Valence Isomerization of Phenoxyl-Imidazolyl Radical Complex Derivatives

Open-shell biradicals have received considerable attention in material science because of their high two-photon absorption cross sections and broad and high absorptive features over the visible region. However, the instability of the biradical caused by the open-shell nature was one of the drawbacks; therefore, novel radical compounds which can suppress unwanted reactions by tuning the open-shell features are desired to expand the versatility of the radical compounds. Here, we report a novel radical-dissociation-type photochromic compound whose photochromic reaction involves a valence isomerization from the open-shell biradical to closed-shell quinoidal forms by using a phenoxyl-imidazolyl radical complex framework. The valence isomerization from the biradical to quinoid forms effectively tunes the open-shell feature in time and drastically changes the spectral features, which were revealed by time-resolved Fourier transform infrared spectroscopy. This novel fast photochromic property not only is important for fundamental spin chemistry but also expands the versatility of the radical compounds for novel advanced photofunctional materials

Fast Photochromism Involving Thermally-Activated Valence Isomerization of Phenoxyl-Imidazolyl Radical Complex Derivatives

Open-shell biradicals have received considerable attention in material science because of their high two-photon absorption cross sections and broad and high absorptive features over the visible region. However, the instability of the biradical caused by the open-shell nature was one of the drawbacks; therefore, novel radical compounds which can suppress unwanted reactions by tuning the open-shell features are desired to expand the versatility of the radical compounds. Here, we report a novel radical-dissociation-type photochromic compound whose photochromic reaction involves a valence isomerization from the open-shell biradical to closed-shell quinoidal forms by using a phenoxyl-imidazolyl radical complex framework. The valence isomerization from the biradical to quinoid forms effectively tunes the open-shell feature in time and drastically changes the spectral features, which were revealed by time-resolved Fourier transform infrared spectroscopy. This novel fast photochromic property not only is important for fundamental spin chemistry but also expands the versatility of the radical compounds for novel advanced photofunctional materials