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Acute effects of theanine, caffeine and theanine-caffeine combination on attention.
Kahathuduwa, CN, Dassanayake, TL, Amarakoon, AMT, Weerasinghe, VS
Nutritional neuroscience. 2017;(6):369-377
Abstract
OBJECTIVE l-theanine is a constituent of tea which is claimed to enhance cognitive functions. We aimed to determine whether theanine and theanine-caffeine combination have acute positive effects on cognitive and neurophysiological measures of attention, compared to caffeine (a positive control) and a placebo in healthy individuals. DESIGN In a placebo-controlled, five-way crossover trial in 20 healthy male volunteers, we compared the effects of l-theanine (200 mg), caffeine (160 mg), their combination, black tea (one cup) and a placebo (distilled water) on cognitive (simple [SVRT] and recognition visual reaction time [RVRT]) and neurophysiological (event-related potentials [ERPs]) measures of attention. We also recorded visual (VEPs) and motor evoked potentials (MEPs) to examine any effects of treatments on peripheral visual and motor conduction, respectively. RESULTS Mean RVRT was significantly improved by theanine (P = 0.019), caffeine (P = 0.043), and theanine-caffeine combination (P = 0.001), but not by tea (P = 0.429) or placebo (P = 0.822). VEP or MEP latencies or SVRT did not show significant inter-treatment differences. Theanine (P = 0.001) and caffeine (P = 0.001) elicited significantly larger mean peak-to-peak N2-P300 ERP amplitudes than the placebo, whereas theanine-caffeine combination elicited a significantly larger mean N2-P300 amplitude than placebo (P < 0.001), theanine (P = 0.029) or caffeine (P = 0.005). No significant theanine × caffeine interaction was observed for RVRT or N2-P300 amplitude. DISCUSSION A dose of theanine equivalent of eight cups of back tea improves cognitive and neurophysiological measures of selective attention, to a degree that is comparable with that of caffeine. Theanine and caffeine seem to have additive effects on attention in high doses.
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Assessing the effects of caffeine and theanine on the maintenance of vigilance during a sustained attention task.
Foxe, JJ, Morie, KP, Laud, PJ, Rowson, MJ, de Bruin, EA, Kelly, SP
Neuropharmacology. 2012;(7):2320-7
Abstract
Caffeine and L-theanine, both naturally occurring in tea, affect the ability to make rapid phasic deployments of attention to locations in space as reflected in behavioural performance and alpha-band oscillatory brain activity (8-14 Hz). However, surprisingly little is known about how these compounds affect an aspect of attention that has been more popularly associated with tea, namely vigilant attention: the ability to maintain focus on monotonous tasks over protracted time-periods. Twenty-seven participants performed the Sustained Attention to Response Task (SART) over a two-hour session on each of four days, on which they were administered caffeine (50 mg), theanine (100 mg), the combination, or placebo in a double-blind, randomized, cross-over fashion. Concurrently, we recorded oscillatory brain activity through high-density electroencephalography (EEG). We asked whether either compound alone, or both in combination, would affect performance of the task in terms of reduced error rates over time, and whether changes in alpha-band activity would show a relationship to such changes in performance. When treated with placebo, participants showed a rise in error rates, a pattern that is commonly observed with increasing time-on-task, whereas after caffeine and theanine ingestion, error rates were significantly reduced. The combined treatment did not confer any additional benefits over either compound alone, suggesting that the individual compounds may confer maximal benefits at the dosages employed. Alpha-band oscillatory activity was significantly reduced on ingestion of caffeine, particularly in the first hour. This effect was not changed by addition of theanine in the combined treatment. Theanine alone did not affect alpha-band activity.
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L-theanine relieves positive, activation, and anxiety symptoms in patients with schizophrenia and schizoaffective disorder: an 8-week, randomized, double-blind, placebo-controlled, 2-center study.
Ritsner, MS, Miodownik, C, Ratner, Y, Shleifer, T, Mar, M, Pintov, L, Lerner, V
The Journal of clinical psychiatry. 2011;(1):34-42
Abstract
OBJECTIVE L-theanine is a unique amino acid present almost exclusively in the tea plant. It possesses neuroprotective, mood-enhancing, and relaxation properties. This is a first study designed to evaluate the efficacy and tolerability of L-theanine augmentation of antipsychotic treatment of patients with chronic schizophrenia and schizoaffective disorder. METHOD 60 patients with DSM-IV schizophrenia or schizoaffective disorder participated in an 8-week, double-blind, randomized, placebo-controlled study. 400 mg/d of L-theanine was added to ongoing antipsychotic treatment from February 2006 until October 2008. The outcome measures were the Positive and Negative Syndrome Scale (PANSS), the Hamilton Anxiety Rating Scale (HARS), the Cambridge Neuropsychological Test Automated Battery (CANTAB) for neurocognitive functioning, and additional measures of general functioning, side effects, and quality of life. RESULTS 40 patients completed the study protocol. Compared with placebo, L-theanine augmentation was associated with reduction of anxiety (P = .015; measured by the HARS scale) and positive (P = .009) and general psychopathology (P < .001) scores (measured by the PANSS 3-dimensional model). According to the 5-dimension model of psychopathology, L-theanine produced significant reductions on PANSS positive (P = .004) and activation factor (P = .006) scores compared to placebo. The effect sizes (Cohen d) for these differences ranged from modest to moderate (0.09-0.39). PANSS negative and CANTAB task scores, general functioning, side effect, and quality of life measures were not affected by L-theanine augmentation. L-theanine was found to be a safe and well-tolerated medication. CONCLUSIONS L-theanine augmentation of antipsychotic therapy can ameliorate positive, activation, and anxiety symptoms in schizophrenia and schizoaffective disorder patients. Further long-term studies of L-theanine are needed to substantiate the clinically significant benefits of L-theanine augmentation.
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A phase II, open-label, randomized study to assess the efficacy and safety of AZD6244 (ARRY-142886) versus pemetrexed in patients with non-small cell lung cancer who have failed one or two prior chemotherapeutic regimens.
Hainsworth, JD, Cebotaru, CL, Kanarev, V, Ciuleanu, TE, Damyanov, D, Stella, P, Ganchev, H, Pover, G, Morris, C, Tzekova, V
Journal of thoracic oncology : official publication of the International Association for the Study of Lung Cancer. 2010;(10):1630-6
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Abstract
INTRODUCTION AZD6244 (ARRY-142886) is a potent, selective MEK inhibitor. This study aimed to evaluate the efficacy and safety of AZD6244 versus pemetrexed as second- or third-line treatment in patients with advanced non-small cell lung cancer (NSCLC). METHODS In this randomized phase II study, patients received either 100 mg oral AZD6244 free-base suspension twice daily or 500 mg/m(2) intravenous pemetrexed once every 3 weeks after pretreatment with a corticosteroid, folic acid, and vitamin B12. The primary end point of the study was the disease progression event count. RESULTS Eighty-four patients were randomized. Disease progression events were experienced by 28 (70%) and 26 (59%) patients in the AZD6244 and pemetrexed groups, respectively. Median progression-free survival was not statistically significantly different between the AZD6244 and pemetrexed groups (67 versus 90 days, respectively; hazard ratio 1.08, two-sided 80% confidence interval = 0.75-1.54; p = 0.79). Two patients in the AZD6244 group had a best response to treatment of partial response. In the pemetrexed group, one patient achieved a complete response and one patient a partial response. Dermatitis acneiform, diarrhea, nausea, and vomiting were the most frequently reported adverse events with AZD6244, compared with fatigue, anemia, nausea, anorexia, and dermatitis acneiform with pemetrexed. CONCLUSIONS Oral AZD6244 showed clinical activity as second- or third-line therapy for patients with advanced NSCLC. In an unselected NSCLC population, there is no suggestion that AZD6244 monotherapy offers any advantage over standard treatment with pemetrexed. Based on preclinical data and recent clinical observations, further development of AZD6244 in NSCLC should focus on BRAF or RAS mutation-positive patients and/or AZD6244-based combination regimens.
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Elderly patients benefit from second-line cytotoxic chemotherapy: a subset analysis of a randomized phase III trial of pemetrexed compared with docetaxel in patients with previously treated advanced non-small-cell lung cancer.
Weiss, GJ, Langer, C, Rosell, R, Hanna, N, Shepherd, F, Einhorn, LH, Nguyen, B, Paul, S, McAndrews, P, Bunn, PA, et al
Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2006;(27):4405-11
Abstract
PURPOSE Numerous prospective and retrospective studies have concluded that elderly patients (> or = 70 years old) achieve a similar survival benefit, with acceptable toxicity, from first-line cytotoxic chemotherapy for the treatment of advanced non-small-cell lung cancer (NSCLC) compared with their younger counterparts. However, few published data exist on the efficacy and tolerability of second-line cytotoxic therapy in this population. PATIENTS AND METHODS Retrospective analysis of a large second-line trial was performed. Data from 571 patients randomly assigned to docetaxel 75 mg/m2 or pemetrexed 500 mg/m2 every 3 weeks were analyzed for efficacy and toxicity comparisons between age groups and treatment arms. RESULTS Eighty-six of 571 patients (15%) were > or = 70 years old, similar to rates of elderly observed in the first-line setting. Elderly patients receiving pemetrexed (n = 47) or docetaxel (n = 39) had a median survival of 9.5 and 7.7 months compared with 7.8 and 8.0 months for younger patients receiving pemetrexed (n = 236) or docetaxel (n = 249), respectively. Elderly patients treated with pemetrexed had a longer time to progression and a longer survival than their counterpart patients treated with docetaxel (not statistically significant). Febrile neutropenia was less frequent in elderly patients treated with pemetrexed (2.5%) compared with docetaxel (19%; P = .025), with only one death as a result of toxicity (docetaxel arm). CONCLUSION Elderly patient participation was similar to rates observed in the first-line setting. There was no significant difference in outcome or toxicity between elderly and younger patients. For elderly patients with advanced NSCLC and good performance status, second-line cytotoxic therapy is appropriate. In this subset, pemetrexed produced a more favorable toxicity profile.
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Liver grafts preserved in Celsior solution as source of hepatocytes for drug metabolism studies: comparison with surgical liver biopsies.
Donato, MT, Serralta, A, Jiménez, N, Pérez, G, Castell, JV, Mir, J, Gómez-Lechón, MJ
Drug metabolism and disposition: the biological fate of chemicals. 2005;(1):108-14
Abstract
Suitability of human liver grafts preserved in Celsior solution (CS) for preparing metabolically competent hepatocyte cultures has been examined. To this end, basal and induced activity and mRNA levels of major hepatic cytochrome P450 (P450) enzymes have been measured. By 24 h in culture, measurable levels of the 10 P450 mRNAs studied were found in all hepatocyte preparations examined, with CYP2E1, CYP2C9, and CYP3A4 mRNAs being the most abundant. Compared with hepatocytes obtained from surgical liver resections (SLRs), lower content of each P450 mRNA was found in hepatocytes from the CS group; however, the relative distribution of individual P450 mRNAs was similar. Similar results were observed after measuring P450 activities. CYP1A2, CYP2A6, CYP2C9, CYP2C19, CYP2E1, and CYP3A4 activities in hepatocytes from CS-flushed grafts were lower than but comparable with those of cultures prepared from SLRs. No differences in the metabolite profile of testosterone were found. Treatment of hepatocytes from CS-preserved grafts with model P450 inducers shows that 2 microM methylcholanthrene only increased CYP1A1 and CYP1A2 mRNAs (>100-fold over control), 1 mM phenobarbital markedly increased CYP2A6, CYP2B6, and CYP3A4 mRNA content (>7-fold), and 50 microM rifampicin highly increased CYP3A4 mRNA levels (>10-fold), whereas minor effects (<3-fold) were observed in CYP2A6, CYP2B6, and CYP2C9 mRNAs. This induction pattern of P450s was similar, in terms of magnitude, reproducibility, and specificity, to that shown in primary hepatocytes from surgical biopsies. Overall, our results indicate that, cold-preserved in CS, liver grafts constitute a valuable source of human hepatocytes for drug metabolism studies.
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Excitotoxicity in neonatal hypoxia.
Johnston, MV
Mental retardation and developmental disabilities research reviews. 2001;(4):229-34
Abstract
Hypoxic-ischemic encephalopathy (HIE) in neonates is a disorder of excessive neuronal excitation that includes seizures, abnormal EEG activity, and delayed failure of oxidative metabolism with elevated levels of lactic acid in the brain. Evidence from experimental models and clinical investigation indicates that HIE is triggered by a profound disruption in the function of glutamate synapses so that re-uptake of glutamate from the synapse is impaired and post-synaptic membranes containing glutamate receptors are depolarized. Severe hypoxemia preferentially depolarizes neuronal membranes, while ischemia probably has greater impact on the activity of glial glutamate re-uptake. Together, severe hypoxia and ischemia trigger a delayed cascade of events that may result in cell death by necrosis and/or apoptosis. Apoptosis is far more prominent in the neonate than in the adult and activation of cysteine proteases such as caspase-3 is a very important pathway in excitotoxic neonatal injury. Understanding the complex molecular networks triggered by an excitotoxic insult in the neonate provides insight into patterns of selective neuronal vulnerability and potential therapeutic strategies.
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Kidney preservation with university of Wisconsin and Celsior solution: a prospective multicenter randomized study.
Faenza, A, Catena, F, Nardo, B, Montalti, R, Capocasale, E, Busi, N, Boggi, U, Vistoli, F, Di Naro, A, Albertazzi, A, et al
Transplantation. 2001;(7):1274-7
Abstract
BACKGROUND Although the University of Wisconsin (U.W.) solution continues to be the most commonly used for intra-abdominal organs, a new solution, Celsior, already used for heart and lungs, has been proposed for kidney and liver preservation. The aim of this research was to assess the effect of Celsior as compared with U.W. on immediate graft function and a 2-year follow-up of kidney transplants. METHODS A prospective multicenter randomized study was designed to evaluate the efficacy of the Celsior solution in the clinical preservation of the kidney. In this report, we present the data collected as of September 2000. One hundred donors were included in the trial resulting in 187 renal transplants. Ninety-nine kidneys were stored in Celsior solution and 88 in U.W. solution. The groups were comparable with regard to donor and recipient characteristics. RESULTS Delayed graft function occurred in 31.3% of the Celsior group and in 33.9% of the U.W. group (P=n.s.). Mean serum creatinine levels and mean daily urinary output were also comparable. Two year graft survival in kidneys preserved with Celsior was 84% as compared with 75% for U.W.-preserved kidneys without any significant statistical difference. CONCLUSIONS Our data show that the preservation of kidneys in Celsior solution in a clinical setting is equivalent to that of U.W. solution. When using Celsior during multiple-organ donor harvesting it would be possible to perform an in situ flush of all intra-abdominal and intrathoracic organs with a single cold storage solution.