共查询到20条相似文献,搜索用时 31 毫秒
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A. BoubakerC. Houzard A. ZouhairP. Got M.V. OrcurtoF. Giammarile 《Médecine Nucléaire》2011,35(8):446-454
In oncology, positron emission computed tomography (PET/CT) has become an essential tool for initial staging, response evaluation and follow-up of cancer patients. Most of the frequent tumors (lung, breast, esophagus, and lymphomas) are highly avid for 18F-fluorodeoxyglucose (18FDG), but prostate cancer has not demonstrated significant uptake of FDG. The development of new tracers labeled with 18F such as choline analogs allowed already to obtain interesting results particularly in patients with biological relapse and inconclusive conventional imaging work-up. The impact of 18F-flurocholine PET/CT on patient management needs to be validated in large studies, but many centers use already this examination in order to guide further management, including radiotherapy planning. 相似文献
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Physicochemical studies of calf thymus chromatin were performed on micromicellar suspensions by thermal denaturation. These diluted suspensions were obtained, by a controlled shearing method, from a compact gel chromatin. Sedimentation and free-flow electrophoresis determined the size distribution of these particles. The most important result is a new transition on the melting profiles corresponding to a sudden increase of solution turbidity. This chromatin solution transition occurs at a higher temperature than usual DNA transition. The degree of « turbidity transitiondiminishes with micelle size but disappears when they are very mildly degraded by DNAases and when F1 histone fraction is removed.This transition is not only size dependent but also depends on the micellar structure. This phenomenon is interpreted as an excluded volume effect by contact between compact and native regions of nucleoprotein micelles and denatured coils of DNA. Our study tried to show that the degree of turbidity transition can be a criterion of chromatin native structure. 相似文献
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Alfonso J. Cruz-JentoftFederico Cuesta Triana Mari Carmen Gómez-CabreraAlfonso López-Soto Ferran MasanésPilar Matía Martín José Antonio Serra RexachDomingo Ruiz Hidalgo Antoni SalvàJosé Viña Francesc Formiga 《Revista espa?ola de geriatría y gerontología》2011,46(2):100
Sarcopenia is a common and prominent geriatric syndrome, of major interest for daily clinical practice of professionals working with older people. The number of affected individuals and its relation with disability, frailty, many chronic diseases, lifestyle and adverse outcomes are extremely relevant for geriatric care. Moreover, biological changes that lead to the loss of muscle mass and strength are intrinsically related to the mechanisms of aging. It is not therefore surprising that research in this field is growing exponentially in recent years, and sarcopenia has been placed in recent years in the forefront of research in geriatric medicine and gerontology.The Spanish Society of Geriatrics and Gerontology has recently created an Observatory of Sarcopenia, which aims to promote educational and research activities in this field. The first activity of the Observatory has been to offer the Spanish speaking scientific community a review of the current status of sarcopenia, that may allow unifying concepts and fostering interest in this promising field of geriatrics. 相似文献
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Ochoa G. Jos 《Biotropica》2000,32(1):146-164
The responses of small mammal communities to forest disturbance by logging were evaluated. The study area was located in the Imataca Forest Reserve (Venezuelan Guayana Region), where vegetation was predominantly lowland rain forest. Field analyses were based on a comparative inventory of species inhabiting primary forests and areas disturbed by selective logging. The taxonomic groups used as indicators of die ecological impact of logging belonged to the orders Didelphimorphia, Chiroptera, and Rodentia (families Sciuridae, Muridae, and Echimyidae). The following sampling methods were used: (1) mist nets; (2) traps in 2.4 ha grids (each with 120 stations: 60 at ground level and 60 in trees); and (3) diurnal and nocturnal sight surveys. Total sampling effort consisted of 1904 net‐hours, 10,320 trap‐nights, and 567 h of direct observations. At least 83 mammalian species inhabited die evaluated forests (74.7 percent corresponding to Chiroptera), of which 15.3 percent were restricted to primary forest. In logged areas, small mammal communities were characterized by: (1) higher abundances of individuals; (2) lower proportions of carnivorous and gleaning insectivorous bats; (3) increases in the relative abundance of frugivorous bat species that eat the fruits of colonizing plants; (4) higher proportions of aerial insectivores (Molossidae) at die lowest levels of die forest; (5) simplification in trophic structure of non‐volant species, widi semiarboreal predator‐omnivores being die dominant guild (followed by terrestrial frugivore‐omnivores); and (6) reduction in the relative abundance of mainly canopy‐associated species. These results are explained by: (1) lower availability of key resources associated with primary forest (e.g., roosts in hollow trunks of mature trees, canopy fruits, and tree‐crown continuity); (2) higher relative abundance of some food resources, such as terrestrial invertebrates and saprophytic plants, principally in areas where primary production is limited by low‐fertility soils; (3) increase of roosting sites under fallen trunks; (4) modification of microclimatic conditions at die understory level as a consequence of a greater incident sunlight after canopy opening; and (5) increase in density of early successional plants. The implications of these results to the conservation of biodiversity in forests managed for timber extraction in die Venezuelan Guayana Region are discussed. 相似文献
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André Fontaine 《L'Anthropologie》2011,(5):616
This article firstly summarizes the process of study of an old collection, which had not been considered since the excavations at the site Les Vachons, started before 1914 and completed around 1939. The studied collection of J. Coiffard, both excavator and inventor of this site, includes four-fifths of the artefacts because, in 1940, he donated approximately one fifth to the Eyzies Museum. For his part, J. Bouyssonie who participated in the excavations for 3 years gave the major part of his own collection to the Archaeological Society of Charentes Angouleme where its condition makes it difficult to analyze. Despite these restrictions, based on statistical comparisons with counts many other sites, I came to the conclusion that the top three layers of Les Vachons are a confirmation of the Gravettian model, developed by B. Bosselin and F. Djindjian through their factor analysis. This model seems much better suited to the stratigraphy of Les Vachons, than all assumptions made by previous analysts in their attempt to bring the industries from the three layers in what remains from the Peyrony model. 相似文献
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Myocardial 123-I-metaiodobenzylguanidine (MIBG) imaging enables the assessment of postganglionic sympathetic cardiac innervation. Recently myocardial 123-I-MIBG scintigraphy has been found to be useful to distinguishing Parkinsońs disease (PD) from other akinetic rigid syndromes. The absence of published guidelines for cardiac 123-I-MIBG imaging makes standardization of procedures among individual users of this technique even more important. Cardiac MIBG study showed markedly decreased uptake in PD, dementia with Lewy bodies (DLB) and pure autonomic failure, which is a common feature of Lewy body disease. The cardiac MIBG uptake is severely impaired even in the early disease stage. Atypical parkinsonian syndromes, including Multiple System Atrophy, Progressive Supranuclear Palsy, and other, show modest reduction of cardiac MIBG uptake. The MIBG study can be used for differentiating patients with extrapyramidal signs and dementia, and might provide useful diagnostic information to discriminate DLB and Alzheime?s disease. 相似文献
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Stimulation of de novo synthesis of δ-aminolevulinate dehydralasc of radishes grown under far-red light .
Density labelling studies of δ-aminolevulinate dehydratase (ALAD) in cotyledons of radish ( Raphanus sativus L. cv. Longue Rave Saumonée) seedlings demonstrate that far-red light stimulates de novo synthesis of ALAD and that the turn-over of this enzyme is very poor. Cycloheximide reduces considerably both the increase of ALAD activity and the incorporation of deuterium in ALAD, which indicates that ALAD synthesis depends upon cytoplasmic ribosomes. 相似文献
Density labelling studies of δ-aminolevulinate dehydratase (ALAD) in cotyledons of radish ( Raphanus sativus L. cv. Longue Rave Saumonée) seedlings demonstrate that far-red light stimulates de novo synthesis of ALAD and that the turn-over of this enzyme is very poor. Cycloheximide reduces considerably both the increase of ALAD activity and the incorporation of deuterium in ALAD, which indicates that ALAD synthesis depends upon cytoplasmic ribosomes. 相似文献
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Advantages are given to illustrate the possibilities of resonance Raman spectroscopy in the studies of biological systems.A relation giving the size of porphinato-core of metalloporphyrins from resonance Raman frequency is proposed. It can be applied to heme, even in lived state.By illuminating the sample through a microscope, resonance Raman effect can be collected from 1 (μm)2 of sample. Spectra of a vegetal-cell wall (pimento) and of a red corpuscle (hemoglobin) are shown as examples. 相似文献
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J Dognin J.L Girardet Y Chapron 《Biochimica et Biophysica Acta (BBA)/General Subjects》1973,297(2):276-284
Polarographic study of the mobilization of ferritin ironPolarographic study allows to propose a model for mobilization of ferritin iron: an equilibrium exists between iron core and small quantities of iron outside the protein.These iron atoms would be lying on electron acceptor sites including SH groups. The number of sites is dependent on iron content of ferritin.Therefore, the iron could be removed by the action of reducing agents such as xanthine oxidase or ascorbic acid, and then chelated by a complexing agent. 相似文献
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Modulation of the xylem response to different types of vascular aggressions The evolution of cells lining the vessels in the stem xylem of carnation was compared in sham-stressed (s. e.), V. dabliae-infected (i V. d.) and P. cinerescens-infected (i P. c.) plants. All experimental stresses triggered ultrastructural changes leading to the appearance of new cell types. In parallel, vacuolar polyphenols were metabolized and dense-core vesicles appeared. These were early and independant phenomena. In all cases the reactions of carnation xylem were stronger against Verticillium than against Phialophora. Differences in vascular gummosis were disclosed whatever the criterion used (speed of installation, relative importance of the phenomenon, level of structural complexity, dynamics of appearance of the different structures). The possible relations between cell structures and gummous secretions were investigated by means of comparison of an efficient defence system (i V. d.) with a deficient one (i P. c.). All the criteria selected for analysis confirm that faced with a specific parasite the host response was disrupted. In other words, the biosynthetic pathways normally used by the plant after a fungal aggression were blocked, slowed or diverted. The differences in the responses of carnation to Verticillium and Phialophora give a picture of parasite specificity in agreement with the model recently proposed by de Wit (1981) for tomato/Cladosporium fulvum. 相似文献
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Jordi Amblàs Novellas Joan Espaulella Panicot Carles Blay Pueyo Núria Molist Brunet Gianni E. Lucchetti d’Aniello Antoni Anglada Arisa Jordi Roca Casas 《Revista espa?ola de geriatría y gerontología》2013
Demographic changes and the economic situation of the recent years have conditioned a turning point in health policies, which have decided to progressively prioritize chronicity care programs. Given that hospital costs were concentrated in attention to patients with chronic diseases, reduction on admissions is now a priority target. 相似文献