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INTRODUCTION: The use of immune checkpoint inhibitors (ICIs) is rapidly expanding in cancer treatment. ICIs have a unique safety profile, characterised by immune-related adverse events (irAEs). The safety profile of ICIs lacks patient experience and perspectives. This study primarily aims to obtain a database for descriptive research on the status of irAEs using the Patient-Reported Outcomes version of the Common Terminology Criteria (PRO-CTCAE) in patients with gastrointestinal cancer, lung cancer and malignant pleural mesothelioma treated with regimens containing ICIs. METHODS AND ANALYSIS: This is an ongoing, multicentre, observational study in Japan. Eligible patients must be at least 20 years old and have been diagnosed with lung cancer, malignant pleural mesothelioma or gastrointestinal cancer and plan to use ICIs. Participants will install the electronic PRO (ePRO) application and report adverse events via ePRO using PRO-CTCAE once weekly for up to 48 weeks. A registry will be established using background information obtained from medical records. The sample size is determined by 1 year projection without using statistical methods. Statistical analyses will include point estimates and 95% CIs for the incidence of each adverse event by cancer type and regimen at each time point. ETHICS AND DISSEMINATION: This research will be conducted per the Declaration of Helsinki, the Ethical Guidelines for Life Science and Medical Research Involving Human Subjects issued by the Ministry of Education, Culture, Sports, Science and Technology and the Ministry of Health, Labor and Welfare, and the revised Personal Information Protection Law. The study protocol was approved by the Ethics Committee (approval ID T2021-0180) of Tokyo Medical University Hospital on 15 October 2021. REGISTRATION DETAILS: The study began enrolling patients in December 2021. The target enrolment is 260; as of October 2022, 141 have been enrolled, and the enrolment is scheduled to end on 30 June 2023. TRIAL REGISTRATION NUMBER: UMIN000046418.
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Neoplasias Gastrointestinales , Neoplasias Pulmonares , Mesotelioma Maligno , Humanos , Adulto Joven , Adulto , Inhibidores de Puntos de Control Inmunológico/efectos adversos , Estudios de Cohortes , Medición de Resultados Informados por el Paciente , Estudios Observacionales como Asunto , Estudios Multicéntricos como AsuntoRESUMEN
BACKGROUND: Olanzapine treatment prevents chemotherapy-induced nausea and vomiting (CINV) in patients receiving highly emetogenic chemotherapy (HEC). However, its role in the secondary prevention of breakthrough CINV in real-world cancer care should be further evaluated. METHOD: We conducted a retrospective study on patients receiving olanzapine to prevent breakthrough CINV refractory to standard antiemetic therapy. The major outcome was improvement in CINV, defined as any downgrade in CINV symptoms, according to the Common Terminology Criteria for Adverse Events. Comprete response was defined as no symptoms in CINV, i.e., Grade 0. These outcomes were compared in the HEC versus non-HEC groups and the standard- (5 or 10 mg/day) versus low- (2.5 mg/day) dose groups. The other outcome measurement was adverse events (AEs). RESULTS: We analyzed 127 patients, including 92 women, with a median age of 50 years (range: 19-89 years). Baseline CINV severity was grade 1, 2, and 3 in 18%, 69%, and 13% of the patients, respectively. After prophylaxis with olanzapine at doses of 2.5, 5, or 10 mg/day, improvement was observed in 105 (83%) patients, with a complete response in 42 patients (33%). The improvement and complete remission rates for the HEC (n = 96) and non-HEC (n = 31) groups were 86% and 71% (p = 0.048) versus 38% and 19% (p = 0.062), respectively. The rates for the standard- (n = 98) and low- (n = 29) dose groups were 86% and 82% (p = 0.568) versus 28% and 52% (p = 0.015), respectively. Thirty-four patients (27%) experienced olanzapine-related AEs, mainly somnolence (n = 28). Grade 3 or higher AEs were not observed. CONCLUSION: Our study results support the clinical application of olanzapine for the secondary prevention of breakthrough CINV.
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BACKGROUND: Pegfilgrastim is widely used for the prevention of febrile neutropenia (FN) in patients receiving myelosuppressive chemotherapy for various types of cancer. However, pegfilgrastim-induced bone pain (PIBP) is a relevant adverse event occurring during cancer treatment. Thus, we aimed to determine the risk factors for PIBP in real-world clinical practice. MAIN BODY: We retrospectively collected the clinical records of patients who received pegfilgrastim to support myelosuppressive chemotherapy with at least a 10% risk of FN between 2015 and 2018 at our center. Patients received pegfilgrastim 3.6 mg between days 2 and 7 after chemotherapy administration (day 1) for primary or secondary prophylaxis against FN. All adverse events were recorded according to the Common Terminology Criteria for Adverse Events. Patients who experienced intermittent bone pain in the back, femur, or other anatomic sites after the pegfilgrastim administration were considered to have PIBP. To evaluate the relationship between PIBP incidence and patient characteristics, we performed univariate and multivariate logistic regression analyses to calculate the odds ratios (ORs) of possible risk factors for PIBP. We analyzed the data of 305 patients (median age: 63 years), who underwent 1220 chemotherapy cycles with pegfilgrastim per cycle. Univariate analysis revealed that female sex (vs. male sex), younger age (< 55 years vs. ≥ 55 years), and solid cancers (vs. hematologic cancers) had significantly higher ORs (p < 0.05). However, only younger age (< 55 years) was an independent risk factor for PIBP on multivariate analysis (OR 3.62, 95% confidence interval 1.51-8.69, p = 0.004). CONCLUSIONS: Younger age (< 55 years) was significantly associated with a higher risk of PIBP among patients receiving chemotherapy with a ≥ 10% risk of FN. Therefore, oncologists should meticulously formulate management plan for PIBP in younger patients after administering pegfilgrastim.
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Background Infusion-related reactions (IRRs) during rituximab administration are occasionally severe and remain problematic in oncology practice. Aim To establish a safer, risk-stratified rituximab protocol for patients with B-cell lymphoma. Method We stratified patients into low-, moderate-, and high-risk groups according to the number of risk factors for IRRs, specifically, low-grade histology and bulky tumors (> 10 cm): Then, the administrating schedule of rituximab (375 mg/m2, diluted in 1 mg/mL concentration) was individualized. For the first rituximab cycle, the low- and moderate-risk groups underwent conventional infusion #1 (25-200 mg/h, ~4.3 h), and the high-risk group underwent long infusion (25-100 mg/h, 6.8 h). Patients in the low-, moderate-, and high-risk groups without IRRs in the first cycle underwent short infusion (100-400 mg/h, 2.3 h), conventional infusion #2 (100-200 mg/h, 3.5 h), and conventional infusion #1, respectively. Patients with IRRs in the first cycle received a second rituximab cycle with the same schedule as the first cycle. The procedure for the third cycle was at the attending physician's discretion. Results Among 81 patients, the overall incidence of IRRs was 28%. IRR incidences in the low- (n = 39), moderate- (n = 35), and high-risk groups (n = 7) were 31%, 20%, and 57%, respectively. All IRRs were grade ≤ 2. The overall conversion rate to short infusion in the third cycle was 54%, without any IRRs. Conclusions Our step-by-step rituximab protocol demonstrated a fewer incidence of severe IRRs among B-cell lymphoma patients receiving rituximab.
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Antineoplásicos , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Linfoma de Células B , Antineoplásicos/efectos adversos , Humanos , Incidencia , Linfoma de Células B/tratamiento farmacológico , Factores de Riesgo , Rituximab/efectos adversosRESUMEN
Patients who undergo multiple-day chemotherapy sessions experience hard-to-treat nausea and vomiting. Currently, there is no effective standard treatment for this condition. This study compared the preventive effect of first-generation 5-hydroxytryptamine 3 receptor antagonists (5-HT3 RAs) and second-generation 5-HT3 RAs palonosetron in multiple-day chemotherapy-induced nausea and vomiting. The design of this study was a retrospective case-control study of patients who received a five-day cisplatin-based chemotherapy and were treated with aprepitant, dexamethasone, granisetron, and ramosetron or palonosetron. The patients were divided into two groups: patients given granisetron and ramosetron (the first-generation group), and those given palonosetron (palonosetron group). The percentage of patients with a complete response or total control was assessed. They were divided into three phases: 0-216 h (overall phase), 0-120 h (remedial phase), and 120-216 h (after phase). The remedial phase was further divided into 0-24 h (early phase) and 24-120 h (later phase). Moreover, the nutritional status of each patient was assessed by noting the patients' total calorie-intake per day and total parenteral nutrition. First-generation 5-HT3 RAs and palonosetron were used for treatment in 18 and 28 patients, respectively. The complete response rate and caloric oral intake of the later phase were higher in the palonosetron group than in the first-generation group. We conclude that palonosetron treatment was more effective than first-generation 5-HT3 RAs in controlling multiple-day chemotherapy-induced nausea and vomiting.
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Antieméticos/administración & dosificación , Bencimidazoles/administración & dosificación , Granisetrón/administración & dosificación , Náusea/tratamiento farmacológico , Palonosetrón/administración & dosificación , Antagonistas del Receptor de Serotonina 5-HT3/administración & dosificación , Vómitos/tratamiento farmacológico , Adulto , Antineoplásicos/efectos adversos , Bleomicina/efectos adversos , Quimioterapia Combinada , Etopósido/efectos adversos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Náusea/inducido químicamente , Neoplasias de Células Germinales y Embrionarias/tratamiento farmacológico , Neoplasias Ováricas/tratamiento farmacológico , Compuestos de Platino/efectos adversos , Estudios Retrospectivos , Neoplasias Testiculares/tratamiento farmacológico , Vómitos/inducido químicamenteRESUMEN
Most excitatory synapses in the brain form on dendritic spines. Two-photon uncaging of glutamate is widely utilized to characterize the structural plasticity of dendritic spines in brain slice preparations in vitro. In the present study, glutamate uncaging was used to investigate spine plasticity, for the first time, in vivo. A caged glutamate compound was applied to the surface of the mouse visual cortex in vivo, revealing the successful induction of spine enlargement by repetitive two-photon uncaging in a magnesium free solution. Notably, this induction occurred in a smaller fraction of spines in the neocortex in vivo (22%) than in hippocampal slices (95%). Once induced, the time course and mean long-term enlargement amplitudes were similar to those found in hippocampal slices. However, low-frequency (1-2 Hz) glutamate uncaging in the presence of magnesium caused spine shrinkage in a similar fraction (35%) of spines as in hippocampal slices, though spread to neighboring spines occurred less frequently than it did in hippocampal slices. Thus, the structural plasticity may occur similarly in the neocortex in vivo as in hippocampal slices, although it happened less frequently in our experimental conditions.
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Espinas Dendríticas/fisiología , Ácido Glutámico/metabolismo , Potenciación a Largo Plazo , Neocórtex/fisiología , Animales , Espinas Dendríticas/metabolismo , Hipocampo/citología , Hipocampo/metabolismo , Hipocampo/fisiología , Magnesio/metabolismo , Ratones , Neocórtex/citología , Neocórtex/metabolismo , Corteza Visual/citología , Corteza Visual/metabolismo , Corteza Visual/fisiologíaRESUMEN
Background Pegfilgrastim is widely used for prophylaxis of febrile neutropenia (FN) in cancer patients receiving chemotherapies. However, the optimal timing of pegfilgrastim administration has not been established. Objective We investigated the effect of the timing of pegfilgrastim administration on the prevention of FN in patients with breast cancer undergoing intermediate-risk chemotherapies. Method We retrospectively analysed the incidence of FN in patients with breast cancer treated at our institution with intermediate-risk chemotherapies and primary or secondary prophylactic pegfilgrastim between 2015 and 2017. The impact of the timing of pegfilgrastim administration on the incidence of FN was evaluated by univariate and multivariate logistic regression analyses. Results Overall, 87 patients received a total of 318 chemotherapy cycles with pegfilgrastim, and 14 patients (16%) experienced FN. In univariate analyses, day 2 pegfilgrastim administration, age of > 65 years, baseline haemoglobin < 12 g/dL, prior history of FN, and presence of recurrent/metastatic disease trended toward an association with FN. Adjustment for these confounding risk factors revealed that day 2 pegfilgrastim administration was associated with a significantly increased risk of FN (odds ratio 11.0, p = 0.009). Conclusion Administrating pegfilgrastim on day 3 or later may prevent FN more effectively among Japanese breast cancer patients receiving intermediate-risk chemotherapies.
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Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Neoplasias de la Mama/tratamiento farmacológico , Filgrastim/administración & dosificación , Neutropenia/inducido químicamente , Neutropenia/tratamiento farmacológico , Polietilenglicoles/administración & dosificación , Adulto , Anciano , Neoplasias de la Mama/epidemiología , Bases de Datos Factuales , Esquema de Medicación , Femenino , Humanos , Persona de Mediana Edad , Neutropenia/epidemiología , Estudios Retrospectivos , Factores de TiempoRESUMEN
Background Infusion-related reactions (IRRs) are a major adverse event of rituximab. Objective To develop a prediction model for IRRs to rituximab among patients with B cell non- Hodgkin's lymphomas (B-NHL). Setting A 1000-bed university hospital in Tokyo. Methods Patients with B-NHL treated with rituximab at our institution from 2004 to 2014 were retrospectively analysed. Chills, fever, rash, nausea, asthenia, headache, cardiovascular symptoms, and respiratory symptoms of any grade, in association with rituximab infusion, were identified as IRRs. Risk factors for IRRs to rituximab found in the intergroup analysis were subsequently evaluated by using multivariate analysis. Main outcome measure Occurrence of IRRs to rituximab. Results A total of 140 patients with various types of B-NHL, including 74% with diffuse large Bcell lymphoma, were analysed. Among them, 55 and 85 patients were assigned to the IRR group and the non-IRR group, respectively. Indolent histological subtypes, bulky disease (>10 cm), B symptoms, higher serum soluble interleukin-2 receptor concentration, and bone marrow involvement were more common in the IRR group. The multivariate logistic regression analysis identified low-grade lymphomas [odds ratio (OR) 2.81, p = 0.017] and bulky disease (OR 2.52, p = 0.037) as independent risk factors for IRRs to rituximab. The incidence rates of IRRs to rituximab among patients with neither, one, or both of these risk factors were 26, 54, and 78%, respectively (χ2 = 16.4, p < 0.001). Conclusions A simple combination of histopathological subtype and bulkiness of disease could predict the risk of IRRs to rituximab among patients with B-NHL.
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Infusiones Intravenosas/efectos adversos , Modelos Estadísticos , Rituximab/administración & dosificación , Adulto , Anciano , Estudios de Casos y Controles , Femenino , Humanos , Incidencia , Linfoma de Células B/tratamiento farmacológico , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de RiesgoRESUMEN
Dendritic spines are the postsynaptic sites of most excitatory synapses in the brain, and spine enlargement and shrinkage give rise to long-term potentiation and depression of synapses, respectively. Because spine structural plasticity is accompanied by remodeling of actin scaffolds, we hypothesized that the filamentous actin regulatory protein cofilin plays a crucial role in this process. Here we investigated the diffusional properties of cofilin, the actin-severing and depolymerizing actions of which are activated by dephosphorylation. Cofilin diffusion was measured using fluorescently labeled cofilin fusion proteins and two-photon imaging. We show that cofilins are highly diffusible along dendrites in the resting state. However, during spine enlargement, wild-type cofilin and a phosphomimetic cofilin mutant remain confined to the stimulated spine, whereas a nonphosphorylatable mutant does not. Moreover, inhibition of cofilin phosphorylation with a competitive peptide disables spine enlargement, suggesting that phosphorylated-cofilin accumulation is a key regulator of enlargement, which is localized to individual spines. Conversely, spine shrinkage spreads to neighboring spines, even though triggered by weaker stimuli than enlargement. Diffusion of exogenous cofilin injected into a pyramidal neuron soma causes spine shrinkage and reduced PSD95 in spines, suggesting that diffusion of dephosphorylated endogenous cofilin underlies the spreading of spine shrinkage and long-term depression.
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Factores Despolimerizantes de la Actina/metabolismo , Actinas/metabolismo , Espinas Dendríticas/metabolismo , Destrina/metabolismo , Animales , Líquido Cefalorraquídeo/metabolismo , Femenino , Hipocampo/metabolismo , Potenciación a Largo Plazo/fisiología , Depresión Sináptica a Largo Plazo/fisiología , Masculino , Plasticidad Neuronal/fisiología , Neuronas/metabolismo , Fosforilación/fisiología , Ratas Sprague-Dawley , Sinapsis/metabolismoRESUMEN
Mutations in presenilin 1 (PS1) and presenilin 2 (PS2) are known to cause early onset of Alzheimer's disease (AD). These proteins comprise the catalytic domain of γ-secretase, which catalyzes the cleavage of ß-amyloid (Aß) from amyloid precursor protein (APP). In recent reports, PS1 and PS2 were linked to the modulation of intracellular calcium ion (Ca(2+)) dynamics, a key regulator of synaptic function. Ca(2+) dysregulation and synaptic dysfunction are leading hypothesis of cognitive dysfunctions during aging and AD progression. Accordingly, manipulations of presenilins by small molecules may have therapeutic potential for the treatment of cognitive dysfunction. In an accompanying report, we showed that chronic treatment with compound-1, a novel γ-secretase modulator (GSM), reduced Aß production and ameliorated cognitive dysfunction in Tg2576 APP transgenic mice. Accordingly, in the present study we showed that single oral administration of compound-1 at 1 and 3mg/kg ameliorated cognitive dysfunction in aged non-transgenic mice. Moreover, compound-1 enhanced synaptic plasticity in hippocampal slices from aged C57BL/6J mice and increased messenger RNA (mRNA) expression of the immediate early gene c-fos, which has been shown to be related to synaptic plasticity in vivo. Finally, compound-1 modulated Ca(2+) signals through PS1 in mouse embryonic fibroblast cells. Taken together, compound-1 ameliorates both Aß pathology and age-related cognitive dysfunctions. Hence, compound-1 may have potential as an early intervention for the cognitive declines that are commonly diagnosed in aged subjects, such as mild cognitive impairment (MCI) and prodromal AD.
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Enfermedad de Alzheimer , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Hipocampo/efectos de los fármacos , Plasticidad Neuronal/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Piridinas/farmacología , Triazoles/farmacología , Animales , Cognición/efectos de los fármacos , Trastornos del Conocimiento/etiología , Modelos Animales de Enfermedad , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Técnicas de Placa-ClampRESUMEN
Neurons connect and transmit information via synapses. The major excitatory and inhibitory (E-I) neurotransmitters are glutamate and γ-amino butyric acid (GABA), respectively. The E-I balance plays an important role in various brain functions. In this review, we summarize the role of GABA on synaptic integration and synaptic plasticity by introducing our own recent findings. In synaptic integration, GABA is considered to inhibit depolarization induced by glutamate and suppress action potentials. We found that GABA also has a more direct role on the synaptic plasticity of excitatory inputs. GABA effectively promotes the shrinkage and elimination of synapses by suppressing local dendritic Ca(2+) signaling, while keeping the Ca(2+) domain of the NMDA receptors intact. In this manner, GABA promoted the activation of calcineurin, which in turn activated cofilin. Interestingly, shrinkage tended to spread, likely due to the spread of cofilin, and induced competitive selection of synapses via its phosphorylation and dephosphorylation. The selection of synapses is key to the reorganization of the central nervous system during development and in adulthood, and GABA plays key roles in various mental disorders, such as autism and schizophrenia. Our results account well for the in vivo GABA functions on synaptic selection, and may help to develop new therapeutic compounds.
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Plasticidad Neuronal/fisiología , Neuronas/metabolismo , Sinapsis/metabolismo , Ácido gamma-Aminobutírico/metabolismo , Potenciales de Acción/fisiología , Animales , Ácido Glutámico/metabolismo , HumanosRESUMEN
Activity-dependent competition of synapses plays a key role in neural organization and is often promoted by GABA; however, its cellular bases are poorly understood. Excitatory synapses of cortical pyramidal neurons are formed on small protrusions known as dendritic spines, which exhibit structural plasticity. We used two-color uncaging of glutamate and GABA in rat hippocampal CA1 pyramidal neurons and found that spine shrinkage and elimination were markedly promoted by the activation of GABAA receptors shortly before action potentials. GABAergic inhibition suppressed bulk increases in cytosolic Ca(2+) concentrations, whereas it preserved the Ca(2+) nanodomains generated by NMDA-type receptors, both of which were necessary for spine shrinkage. Unlike spine enlargement, spine shrinkage spread to neighboring spines (<15 µm) and competed with their enlargement, and this process involved the actin-depolymerizing factor ADF/cofilin. Thus, GABAergic inhibition directly suppresses local dendritic Ca(2+) transients and strongly promotes the competitive selection of dendritic spines.
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Señalización del Calcio/fisiología , Espinas Dendríticas/fisiología , Ácido gamma-Aminobutírico/fisiología , Animales , Espinas Dendríticas/patología , Femenino , Hipocampo/metabolismo , Hipocampo/patología , Masculino , Técnicas de Cultivo de Órganos , Ratas , Ratas Sprague-DawleyRESUMEN
GABA (γ-amino-butylic acid)-mediated inhibition in the dendrites of CA1 pyramidal neurons was characterized by two-photon uncaging of a caged-GABA compound, BCMACM-GABA, and one-photon uncaging of RuBi-GABA in rat hippocampal slice preparations. Although we found that GABA(A)-mediated currents were diffusely distributed along the dendrites, currents elicited at the branch points of the apical dendritic trunk were approximately two times larger than those elsewhere in the dendrite. We examined the inhibitory action of the GABA-induced currents on Ca(2+) transients evoked with a single back-propagating action potential (bAP) in oblique dendrites. We found that GABA uncaging selectively inhibited the Ca(2+) transients in the region adjacent (<20 µm) to the uncaging site, and that GABA uncaging was effective only within a short period after bAP (<20 ms). The strength of inhibition was linearly related to the amplitudes of the GABA currents, suggesting that the currents inhibited a sustained, subthreshold after-depolarization without preventing propagation of bAP. GABA uncaging at the dendritic branch points inhibited Ca(2+) transients farther into dendritic branches (>20 µm). Our data indicate that GABA inhibition results in spatially confined inhibition of Ca(2+) transients shortly after bAP, and suggest that this effect is particularly potent at the dendritic branch points where GABA receptors cluster.
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Región CA1 Hipocampal/citología , Calcio/metabolismo , Dendritas/metabolismo , Potenciales Postsinápticos Inhibidores , Receptores de GABA-A/metabolismo , Ácido gamma-Aminobutírico/metabolismo , Potenciales de Acción , Animales , Difusión , Conductividad Eléctrica , Transporte de Proteínas , Ratas , Ratas Sprague-DawleyRESUMEN
We investigated the cytotoxicity of six neolignans (1-6), which are similar in structure to furanocyclohexenone with an angular allyl group, in human neuroblastoma cell lines (IMR-32, LA-N-1, NB-39, SK-N-SH) and normal cells [human umbilical vein endothelial cells (HUVEC) and human dermal fibroblasts (HDF)] using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Two neolignans, ferrearin C (1) and 2, showed significant cytotoxicity in neuroblastoma cells. Typical morphologic features of apoptosis were observed for the ferrearin-type neolignans using Hoechst 33342, and apoptotic cytoplasmic membrane inversion was also induced by ferrearin-type neolignans in IMR-32. Furthermore, a Proteome Profiler Array showed that the ferrearin-type neolignans induced the marked expression of heme oxygenase-1 (HO-1). In a western blot analysis, ferrearin C (1) increased the level of Bax and reduced the level of survivin, indicating the activation of the mitochondrial pathway of apoptosis.
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Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Hemo-Oxigenasa 1/metabolismo , Lignanos/farmacología , Neuroblastoma/metabolismo , Antineoplásicos/química , Western Blotting , Línea Celular , Línea Celular Tumoral , Citometría de Flujo , Hemo-Oxigenasa 1/genética , Humanos , Proteínas Inhibidoras de la Apoptosis/genética , Proteínas Inhibidoras de la Apoptosis/metabolismo , Lignanos/química , Modelos Biológicos , Estructura Molecular , Survivin , Proteína X Asociada a bcl-2/genética , Proteína X Asociada a bcl-2/metabolismoRESUMEN
Structural plasticity of dendritic spines underlies learning, memory and cognition in the cerebral cortex. We here summarize fifteen rules of spine structural plasticity, or 'spine learning rules.' Together, they suggest how the spontaneous generation, selection and strengthening (SGSS) of spines represents the physical basis for learning and memory. This SGSS mechanism is consistent with Hebb's learning rule but suggests new relations between synaptic plasticity and memory. We describe the cellular and molecular bases of the spine learning rules, such as the persistence of spine structures and the fundamental role of actin, which polymerizes to form a 'memory gel' required for the selection and strengthening of spine synapses. We also discuss the possible link between transcriptional and translational regulation of structural plasticity. The SGSS mechanism and spine learning rules elucidate the integral nature of synaptic plasticity in neuronal network operations within the actual brain tissue.
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Espinas Dendríticas/fisiología , Espinas Dendríticas/ultraestructura , Aprendizaje/fisiología , Plasticidad Neuronal/fisiología , Animales , Encéfalo/citología , Encéfalo/fisiología , Humanos , Sinapsis/fisiología , Sinapsis/ultraestructuraRESUMEN
We have synthesized a photosensitive (or caged) 4-carboxymethoxy-5,7-dinitroindolinyl (CDNI) derivative of gamma-aminobutyric acid (GABA). Two-photon excitation of CDNI-GABA produced rapid activation of GABAergic currents in neurons in brain slices with an axial resolution of approximately 2 mum and enabled high-resolution functional mapping of GABA-A receptors. Two-photon uncaging of GABA, the main inhibitory neurotransmitter, should allow detailed studies of receptor function and synaptic integration with subcellular precision.