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158 result(s) for "Nobuaki Matsui"
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Cortical Excitability and Activation of TrkB Signaling During Rebound Slow Oscillations Are Critical for Rapid Antidepressant Responses
Rapid antidepressant effects of ketamine become most evident when its psychotomimetic effects subside, but the neurobiological basis of this “lag” remains unclear. Laughing gas (N 2 O), another NMDA-R ( N -methyl- d -aspartate receptor) blocker, has been reported to bring antidepressant effects rapidly upon drug discontinuation. We took advantage of the exceptional pharmacokinetic properties of N 2 O to investigate EEG (electroencephalogram) alterations and molecular determinants of antidepressant actions during and immediately after NMDA-R blockade. Effects of the drugs on brain activity were investigated in C57BL/6 mice using quantitative EEG recordings. Western blot and qPCR were used for molecular analyses. Learned helplessness (LH) was used to assess antidepressant-like behavior. Immediate-early genes (e.g., bdnf ) and phosphorylation of mitogen-activated protein kinase—markers of neuronal excitability—were upregulated during N 2 O exposure. Notably, phosphorylation of BDNF receptor TrkB and GSK3β (glycogen synthase kinase 3β) became regulated only gradually upon N 2 O discontinuation, during a brain state dominated by slow EEG activity. Subanesthetic ketamine and flurothyl-induced convulsions (reminiscent of electroconvulsive therapy) also evoked slow oscillations when their acute pharmacological effects subsided. The correlation between ongoing slow EEG oscillations and TrkB-GSK3β signaling was further strengthened utilizing medetomidine, a hypnotic-sedative agent that facilitates slow oscillations directly through the activation of α 2 -adrenergic autoreceptors. Medetomidine did not, however, facilitate markers of neuronal excitability or produce antidepressant-like behavioral changes in LH. Our results support a hypothesis that transient cortical excitability and the subsequent regulation of TrkB and GSK3β signaling during homeostatic emergence of slow oscillations are critical components for rapid antidepressant responses.
Quasi-static analysis of soft rock failure characteristics targeted to cyclic direct shear test
In Japan, the disastrous effects of the 2011 Tohoku Earthquake has affected seismic design. Furthermore, there is an increasing need for dynamic nonlinear analysis that can consider large strain levels in assessing the seismic resilience of essential structures such as nuclear power plants. However, the applicability of dynamic nonlinear analysis methods to rock masses has not yet been fully evaluated. Their applicability needs to be confirmed by dynamic phenomena, such as shaking table tests. Herein, as a preliminary step, quasi-static analyses of cyclic direct shear tests were conducted to validate the constitutive model. Soft rock samples with relatively few fractures were used as the testing material. In the tests, the load was applied in multiple steps by increasing the loading amplitude at each step, with a loading frequency of 0.1 Hz. The quasi-static analyses revealed that, although an existing constitutive model generally reproduced the shear load–displacement relationship obtained in the tests from small displacement levels to peak strength, discrepancies emerged beyond peak strength. Therefore, we focused on the post-failure history damping characteristics of the soft rocks and added a damping constant after rock failure to the existing constitutive model. Consequently, the accuracy of the values of the stress history beyond peak strength was improved by more than 10%, and the reproducibility of the shear load–displacement relationship improved. Therefore, the applicability of the improved constitutive model was confirmed for conditions of quasi-static cyclic loading of soft rock with few fractures, from small displacement levels to beyond peak strength.
Influence of filtering on the effective concentration and sterility of a 2% cyclosporine ophthalmic solution: a quality improvement perspective
Background Pharmaceutical companies do not sell formulations for all diseases; thus, healthcare workers have to treat some diseases by concocting in-hospital preparations. An example is the high-concentration 2% cyclosporine A (CyA) ophthalmic solution. Utilizing a filter in sterility operations is a general practice for concocting in-hospital preparations, as is the case for preparing a 2% CyA ophthalmic solution. However, whether filtering is appropriate concerning the active ingredient content and bacterial contamination according to the post-preparing quality control of a 2% CyA ophthalmic solution is yet to be verified. Methods We conducted particle size, preparation concentration, and bacterial contamination studies to clarify aforementioned questions. First, we measured the particle size of CyA through a laser diffraction particle size distribution. Next, we measured the concentration after preparation with or without a 0.45-µm filter operation using an electrochemiluminescence immunoassay. Finally, bacterial contamination tests were conducted using an automated blood culture system to prepare a 2% CyA ophthalmic solution without a 0.45 μm filtering. Regarding the pore size of the filter in this study, it was set to 0.45 μm with reference to the book (the 6th edition) with recipes for the preparation of in-hospital preparations edited by the Japanese Society of Hospital Pharmacists. Results CyA had various particle sizes; approximately 30% of the total particles exceeded 0.45 μm. The mean ± standard deviation of filtered and non-filtered CyA concentrations in ophthalmic solutions were 346.51 ± 170.76 and 499.74 ± 76.95ng/mL, respectively ( p  = 0.011). Regarding bacterial contamination tests, aerobes and anaerobes microorganisms were not detected in 14 days of culture. Conclusions Due to the results of this study, the concentration of CyA may be reduced by using a 0.45-µm filter during the preparation of CyA ophthalmic solutions, and furthermore that the use of a 0.45-µm filter may not contribute to sterility when preparing CyA ophthalmic solutions.
Nimodipine Activates TrkB Neurotrophin Receptors and Induces Neuroplastic and Neuroprotective Signaling Events in the Mouse Hippocampus and Prefrontal Cortex
The L-type calcium channel blocker nimodipine improves clinical outcome produced by delayed cortical ischemia or vasospasm associated with subarachnoid hemorrhage. While vasoactive mechanisms are strongly implicated in these therapeutic actions of nimodipine, we sought to test whether nimodipine might also regulate neurotrophic and neuroplastic signaling events associated with TrkB neurotrophin receptor activation. Adult male mice were acutely treated with vehicle or nimodipine (10 mg/kg, s.c., 1.5 h) after which the phosphorylation states of TrkB, cyclic-AMP response element binding protein (CREB), protein kinase B (Akt), extracellular regulated kinase (ERK), mammalian target of rapamycin (mTor) and p70S6 kinase (p70S6k) from prefrontal cortex and hippocampus were assessed. Nimodipine increased the phosphorylation of the TrkB catalytic domain and the phosphoslipase-Cγ1 (PLCγ1) domain, whereas phosphorylation of the TrkB Shc binding site remained unaltered. Nimodipine-induced TrkB phosphorylation was associated with increased phosphorylation levels of Akt and CREB in the prefrontal cortex and the hippocampus whereas phosphorylation of ERK, mTor and p70S6k remained unaltered. Nimodipine-induced TrkB signaling was not associated with changes in BDNF mRNA or protein levels. These nimodipine-induced changes on TrkB signaling mimic those produced by antidepressant drugs and thus propose common mechanisms and long-term functional consequences for the effects of these medications. This work provides a strong basis for investigating the role of TrkB-associated signaling underlying the neuroprotective and neuroplastic effects of nimodipine in translationally relevant animal models of brain trauma or compromised synaptic plasticity.
Generation of Mast Cells from Mouse Fetus: Analysis of Differentiation and Functionality, and Transcriptome Profiling Using Next Generation Sequencer
While gene knockout technology can reveal the roles of proteins in cellular functions, including in mast cells, fetal death due to gene manipulation frequently interrupts experimental analysis. We generated mast cells from mouse fetal liver (FLMC), and compared the fundamental functions of FLMC with those of bone marrow-derived mouse mast cells (BMMC). Under electron microscopy, numerous small and electron-dense granules were observed in FLMC. In FLMC, the expression levels of a subunit of the FcεRI receptor and degranulation by IgE cross-linking were comparable with BMMC. By flow cytometry we observed surface expression of c-Kit prior to that of FcεRI on FLMC, although on BMMC the expression of c-Kit came after FcεRI. The surface expression levels of Sca-1 and c-Kit, a marker of putative mast cell precursors, were slightly different between bone marrow cells and fetal liver cells, suggesting that differentiation stage or cell type are not necessarily equivalent between both lineages. Moreover, this indicates that phenotypically similar mast cells may not have undergone an identical process of differentiation. By comprehensive analysis using the next generation sequencer, the same frequency of gene expression was observed for 98.6% of all transcripts in both cell types. These results indicate that FLMC could represent a new and useful tool for exploring mast cell differentiation, and may help to elucidate the roles of individual proteins in the function of mast cells where gene manipulation can induce embryonic lethality in the mid to late stages of pregnancy.
Health-related quality of life of colorectal cancer patients receiving oral UFT plus leucovorin compared with those with surgery alone
Background Adjuvant chemotherapy of oral uracil/ftorafur (UFT) plus leucovorin (LV) has been accepted as the standard of care in the treatment of patients with stage II and III carcinoma of the colon. The objective of the study was to compare HRQOL reported by patients receiving oral UFT plus LV (UFT/LV group) versus no adjuvant treatment (control group) following surgery for colorectal cancer. Methods Ninety nine patients in the UFT/LV group and 83 in the control group participated. HRQOL was assessed with the European Organization for Research and Treatment of Cancer QLQ-C30 and HRQOL data measured longitudinally following surgery were compared between the groups. Results Eighty-eight percent (87 of 99) received all scheduled doses of UFT plus LV during the first three cycles, and 82 percent (81 of 99) did so for five cycles. The most common type of toxicity in the UFT/LV group was fatigue, which was generally mild. Six patients each had grade 3 diarrhea or anorexia. There were significant differences in the scores for role function, and specific limitations such as fatigue, nausea, and vomiting, dyspnoea, appetite loss, and financial difficulties, which deteriorated in the UFT/LV group. Conclusions HRQOL in colorectal cancer patients with adjuvant chemotherapy with oral UFT plus LV deteriorated during this phase of treatment compared with those with surgery alone, despite the biased stage of tumor between the groups. Symptom management and social support would improve HRQOL in such a group of patients.
Health-related quality of life in patients with advanced colorectal cancer : results from a phase II study of S-1 combined with irinotecan (CPT-11)
Background We carried out this study to examine the health-related quality of life (HRQOL) of patients with advanced colorectal cancer treated with the oral fluoropyrimidine S-1 plus irinotecan (CPT-11). Methods HRQOL was assessed at baseline (pretreatment) and at 5-week intervals during treatment, using the European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-CR38 questionnaires. The HRQOL data for 12 preselected scales and 21 courses of treatment were then analyzed longitudinally. Results Thirty-seven patients completed the baseline and post-treatment HRQOL assessments. Statistically significant differences between the baseline and post-treatment HRQOL scores were observed for the global QOL, social function, and pain scales (all QLQ-C30), as well as the body image, future perspective, gastrointestinal tract symptoms, weight loss, and chemotherapy side effects scales (all QLQ-CR38); favorable post-treatment results were observed for all the scales except for body image and chemotherapy side effects, for which post-treatment deteriorations were observed. The changes in body image, future perspective, weight loss, and chemotherapy side effects were each greater than ten points and seemed clinically significant. Conclusion Combined treatment with S-1 plus CPT-11 resulted in an acceptable deterioration in HRQOL functioning and symptoms, compared with baseline levels.
Lipoteichoic acid improves the capability of mast cells in the host defense system against bacteria
Objectives and design We investigated the effects of microbial components on the uptake of microbes by mast cells (MCs), and studied the change in cytokine production in MCs after bacterial uptake. Material or subjects LAD2 human mast cells, cord-blood and peripheral-blood derived MCs were employed to analyze their surface molecule expression and cytokine generation by flow cytometry. Bacterial internalization in these MCs was observed by confocal microscopy and flow cytometry. Results Complement receptor 3 expression was augmented by LTA but not by PGN or 3CpG-oligodeoxynucleotide. LTA also enhanced the uptake of opsonized bacteria (over twofold augmentation). After bacterial uptake, MCs augmented the production of chemoattractant cytokines for neutrophils, while Th1 and Th2 cytokine production showed little or no change. Conclusions LTA increases the capability of the MC as a sentinel in the host immune response, and some bacterial components direct human MC function towards innate immunity after pathogen infection.
P11 promoter methylation predicts the antidepressant effect of electroconvulsive therapy
Although electroconvulsive therapy (ECT) is among the most effective treatment options for pharmacoresistant major depressive disorder (MDD), some patients still remain refractory to standard ECT practise. Thus, there is a need for markers reliably predicting ECT non/response. In our study, we have taken a novel translational approach for discovering potential biomarkers for the prediction of ECT response. Our hypothesis was that the promoter methylation of p11, a multifunctional protein involved in both depressive-like states and antidepressant treatment responses, is differently regulated in ECT responders vs. nonresponders and thus be a putative biomarker of ECT response. The chronic mild stress model of MDD was adapted with the aim to obtain rats that are resistant to conventional antidepressant drugs (citalopram). Subsequently, electroconvulsive stimulation (ECS) was used to select responders and nonresponders, and compare p11 expression and promoter methylation. In the rat experiments we found that the gene promoter methylation and expression of p11 significantly correlate with the antidepressant effect of ECS. Next, we investigated the predictive properties of p11 promoter methylation in two clinical cohorts of patients with pharmacoresistant MDD. In a proof-of-concept clinical trial in 11 patients with refractory MDD, higher p11 promoter methylation was found in responders to ECT. This finding was replicated in an independent sample of 65 patients with pharmacoresistant MDD. This translational study successfully validated the first biomarker reliably predicting the responsiveness to ECT. Prescreening of this biomarker could help to identify patients eligible for first-line ECT treatment and also help to develop novel antidepressant treatment procedures for depressed patients resistant to all currently approved antidepressant treatments.
Physiological basis underlying antidepressant-induced activation of TrkB receptors
We show that both pharmacological and non-pharmacological treatments of depression activate TrkB receptors - a well-established target of antidepressants - by inducing a physiological response coupled to sedation. Several rapid-acting antidepressants trigger TrkB signaling by evoking a state associated with electroencephalographic slow-wave activity, behavioral immobility, reduced cerebral glucose utilization, and lowered body temperature. Remarkably, antidepressant-induced TrkB signaling was not compromised in animals exhibiting reduced activity-dependent release of BDNF but was diminished by maintaining animals in warm ambient temperature. Most importantly, prevention of the hypothermic response attenuated the behavioral effects produced by rapid-acting antidepressant nitrous oxide. Our results suggest that the phenomenon underlying TrkB transactivation - changes in energy expenditure and thermoregulation - is essential, but not sufficient, for antidepressant responses. Indeed, regardless of differential clinical and pharmacodynamic properties, all drugs that disrupt energy metabolism and induce hypothermia activated TrkB. This study challenges pharmacology-centric hypotheses regarding antidepressant effects and highlight the role of complex changes in bioenergetics and thermoregulation. Competing Interest Statement W.T., T.R. and S.K. are listed as co-inventors on a patent wherein new EEG-based tools enabling the development of rapid-acting antidepressants and the efficacy monitors thereof are disclosed. W.T., T.R. and S.K. have assigned their patent rights to the University of Helsinki but will share a percentage of any royalties that may be received by the University of Helsinki.