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Human brain preparations obtained from either the putamen, thalamus, hippocampus or lateral occipital gyrus p-hydroxylate phenylethylamine to tyramine, a reaction carried out by a microsomal (100,000 xg pellet) membrane bound, NADPH-requiring enzyme. This is a minor metabolic pathway occurring in chronic psychiatric patients, as well as in age-comparable controls. 相似文献
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M Mason M E Wolf A D Mosnaim 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1983,76(1):215-219
The mechanism of phenylethylamine (PEA) uptake by in vitro rabbit erythrocyte preparations involve both a larger component of passive diffusion and an Na+-dependent facilitated transport system. This is reflected by the fast rate and lack of saturation of PEA erythrocyte uptake, and by the decrease in PEA tissue/medium ratio when the amine was incubated in an Na+-free medium or in the presence of ouabain. Results obtained after the addition of iodoacetamide or by the use of glucose-free medium suggest the Na+-K+ gradient as the driving force responsible for operation of the carrier mechanism. Preliminary results indicate that amphetamine PEA share a similar mechanism for their uptake by rabbit erythrocytes. At the levels normally present in rabbit blood (c. 1 X 10(-8)M), about one-third of the PEA is found in the serum and only a very small portion of it (less than 1%) is present as the "biologically active" non-ionized amine. Most of the remaining phenylethylamine is bound to plasma protein or inside the erythrocytes. 相似文献
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An efficient and specific extraction procedure is described for the isolation of 2-phenylethylamine (PEA) from biological material. The method employed, which involves n-hexane extraction from highly alkalinized samples, substantially eliminates most of catecholamines, indoleamines, their presumed metabolites and amino acid precursors as well as those of PEA itself.Characteristics of a chemical reaction used for the quantitation of this amine, which involves a pH and chloride ion dependent oxidation of this compound by Ce(SO4)2, are also described. This reaction could also be used for the quantitation of 2-hydroxy-2-phenylethylamine, phenylacetic acid, phenylacetaldehyde and phenylethanol. Using the described procedure, PEA levels were determined in different human, cat and rabbit organs, including brain, of nonpretreated animals as well as in human urine. 相似文献
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Biosynthesis of brain 2-phenylethylamine: influence of decarboxylase inhibitors and D-amphetamine 总被引:1,自引:0,他引:1
2-Phenylethylamine (PEA) is an endogenous brain amine which probably modulates affective behavior. Using a gas-liquid chromatographic method for the quantification of PEA (as its dinitrophenyl-sulfonic acid derivative), we found in rabbits 340.9 ± 45.8 ng of PEA/g of wet brain. Brain PEA levels were markedly decreased by the ip administration of 200 mg/Kg, 4 hrs before sacrifice, of the L-aromatic amino acid decarboxylase inhibitors α-methyldopa (28.2 ± 5.1 ng/g), L-α-methyldopa hydrazine (MK-486 [66.9 ± 13.0 ng/g]) or a combination of both (30.0 ± 3.3 ng/g). Since MK-486 inhibits only peripheral decarboxylase, brain PEA must be in part of peripheral origin. Another decarboxylase inhibitor, RO 4-4602 mg/Kg, 4 hrs before sacrifice) failed to affect brain PEA content. D-amphetamine (10 mg/Kg) induced a small depletion of PEA after 30 min in untreated animals; when given in combination with RO 4-4602, brain PEA content was markedly decreased. This supports the view that amphetamine releases PEA and stimulates its synthesis. 相似文献
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AB Zarafi AM Emechebe AD Akpa O Alabi 《Archives Of Phytopathology And Plant Protection》2013,46(4):261-268
Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight. 相似文献
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Background
Organisms are capable of developing different phenotypes by altering the genes they express. This phenotypic plasticity provides a means for species to respond effectively to environmental conditions. One of the most dramatic examples of phenotypic plasticity occurs in the highly social hymenopteran insects (ants, social bees, and social wasps), where distinct castes and sexes all arise from the same genes. To elucidate how variation in patterns of gene expression affects phenotypic variation, we conducted a study to simultaneously address the influence of developmental stage, sex, and caste on patterns of gene expression in Vespula wasps. Furthermore, we compared the patterns found in this species to those found in other taxa in order to investigate how variation in gene expression leads to phenotypic evolution. 相似文献7.
Ballard C Lana MM Theodoulou M Douglas S McShane R Jacoby R Kossakowski K Yu LM Juszczak E;Investigators DART AD 《PLoS medicine》2008,5(4):e76
Background
There have been increasing concerns regarding the safety and efficacy of neuroleptics in people with dementia, but there are very few long-term trials to inform clinical practice. The aim of this study was to determine the impact of long-term treatment with neuroleptic agents upon global cognitive decline and neuropsychiatric symptoms in patients with Alzheimer disease.Methods and Findings
Design: Randomised, blinded, placebo-controlled parallel two-group treatment discontinuation trial.Setting: Oxfordshire, Newcastle and Gateshead, London and Edinburgh, United Kingdom.Participants: Patients currently prescribed the neuroleptics thioridazine, chlorpromazine, haloperidol trifluoperazine or risperidone for behavioural or psychiatric disturbance in dementia for at least 3 mo.Interventions: Continue neuroleptic treatment for 12 mo or switch to an identical placebo.Outcome measures: Primary outcome was total Severe Impairment Battery (SIB) score. Neuropsychiatric symptoms were evaluated with the Neuropsychiatric Inventory (NPI).Results: 165 patients were randomised (83 to continue treatment and 82 to placebo, i.e., discontinue treatment), of whom 128 (78%) commenced treatment (64 continue/64 placebo). Of those, 26 were lost to follow-up (13 per arm), resulting in 51 patients per arm analysed for the primary outcome. There was no significant difference between the continue treatment and placebo groups in the estimated mean change in SIB scores between baseline and 6 mo; estimated mean difference in deterioration (favouring placebo) −0.4 (95% confidence interval [CI] −6.4 to 5.5), adjusted for baseline value (p = 0.9). For neuropsychiatric symptoms, there was no significant difference between the continue treatment and placebo groups (n = 56 and 53, respectively) in the estimated mean change in NPI scores between baseline and 6 mo; estimated mean difference in deterioration (favouring continue treatment) −2.4 (95% CI −8.2 to 3.5), adjusted for baseline value (p = 0.4). Both results became more pronounced at 12 mo. There was some evidence to suggest that those patients with initial NPI ≥ 15 benefited on neuropsychiatric symptoms from continuing treatment.Conclusions
For most patients with AD, withdrawal of neuroleptics had no overall detrimental effect on functional and cognitive status. Neuroleptics may have some value in the maintenance treatment of more severe neuropsychiatric symptoms, but this benefit must be weighed against the side effects of therapy.Trial registration: Cochrane Central Registry of Controlled Trials/National Research Register (#ISRCTN33368770). 相似文献8.
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Kate L E Phillips Neil Chiverton Anthony LR Michael Ashley A Cole Lee M Breakwell Gail Haddock Rowena AD Bunning Alison K Cross Christine L Le Maitre 《Arthritis research & therapy》2013,15(6):R213