Nouvelles molécules non émettrices de positons : traceurs gamma

The dramatic development of PET tracers, together with doubts related to gamma emitters (especially when considering the molybden production crisis) have questioned the future of such single-photon emitters tracers, mainly when thinking about new and innovative molecules. This paper offers several ways for discussion, and aims to demonstrate that such tracers will have for long time still great interest and usefulness, being complementary rather than alternative with PET tracers.     

Nouveaux traceurs en tomographie par émission de positons : un second souffle pour le ciblage de l’hypoxie tumorale ?

There is an increasing interest for targeting of tumor hypoxia and our paper aimed to emphasize the main points of this topic. We review new insights at cellular level and focus on the leading part of hypoxia inducible factor one alpha and its connections with angiogenesis. We shortly describe different methods to assess tissue hypoxia then zoom on to positron emission tomography and its acknowledged tracers ¹⁸F-fluoromisonidazole and ¹⁸F-fluoroerythronitroimidazole. Recent studies concerning two new promising tracers Cu(II)-diacetyl-bis(N(4)-methylthiosemicarbazone) and FAZA are reviewed, and the respective value of the tracers is discussed.     

Prise en charge des cancers de la prostate : points de vue du radiothérapeute

In 2011, the prostate cancer positions itself clearly like a problem of public health. The radiotherapy has shown these twenty last years significant improvements with the advent of the three-dimensional conformation radiotherapy as a standard in the treatment of the adenocarcinoma prostate cancer, and now with the contribution of the modulation of intensity which makes it possible to consider an increment of amount on estimated target volume without toxicity added to the organs at risks. Radio-hormonotherapy association for high-risk cancers also went to current practice. The nuclear medicine through new tracers and new indications probably will allow the experts dealing with these patients to better define the indications and to better distinguish the patients who will profit authentically from a therapeutic strategy more than of another, and even to associate them…     

Cancer de la prostate : utilité de la TEP-TDM à la F-fluorocholine

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.     

Guías clínicas de fractura de cadera. Comparación de sus principales recomendaciones

Hip fracture is the most severe complication of osteoporosis, and despite being a frequent health problem, there is a wide variability in both the health care provided to these patients and the results achieved after their treatment. Clinical guidelines are a tool that helps to reduce this variability. The authors of this review try to give a panoramic and comparative view of the key recommendations proposed by the main guidelines for the hospital care of hip fracture patients. Recommendations on the care in the acute phase are reviewed, particularly the initial hospital management, use of tools, preventive measures to avoid medical complications, surgery related aspects, treatment of usual clinical problems, and shared orthopaedic and geriatric care. Circulating and putting into practice the main recommendations will help to improve the health care provided to these patients and obtain better outcomes.     

Elaboración de una herramienta para la estimación del riesgo de mortalidad a corto y medio plazo tras el alta de una Unidad de Hospitalización de Agudos de Geriatría

Objectives

To identify predictive factors for 6 and 12-months mortality after discharge from a geriatric acute care unit, and from these, derive a mortality-risk index.

Methods and analysis

Prospective cohort study will be conducted on patients over 70 years-old admitted to a geriatric acute care unit and survived to hospital discharge. The main outcome measure will be mortality at 6 months and 12 months after discharge. Independent variables include sociodemographics, functional status, comorbidities, and clinical and laboratory characteristics. Risk factors associated with mortality will be constructed using multivariate logistic regression models. To build the mortality index, points will be assigned to each risk factor by dividing each beta coefficient in the logistic model by the lowest beta coefficient. A score will be assigned to each subject by adding up the points for each risk factor present in the model. The predictive accuracy of the model will be determined by comparing the predicted versus observed mortality in the study population and calculating the area under the ROC curves in both populations.

Conclusions

The risk-mortality index developed would allow an easy estimate to be made of individual risk of death at 6 months and 12 months after discharge from a geriatric acute care unit, with the purpose of establishing care plans and individualising treatment, according to real objectives.     

Tomographie par émission de positons et cancer de la prostate

Positron emission tomography (PET) is a major imaging modality in oncology. Fluorodeoxyglucose (FDG) PET is of limited usefulness in prostate cancer, be it for initial staging or for detection of recurrence. New PET tracers could improve PET performances in prostate cancer staging and when recurrence is suspected. Lipid metabolism tracers, such as choline and fluorine-18-labelled choline analogues, seem to be promising in these indications. The impact of these PET examinations on patient management should be further evaluated, taking into consideration the new therapeutic strategies, in particular salvage local treatment in case of isolated local recurrence.     

Comment l’imagerie nucléaire modifie-t-elle la prise en charge par radiothérapie des cancers de prostate ?

Using new tracers such as fluorocholine or gallium-PSMA, the definition of localized prostate cancers and tumor relapses is profoundly altered. Moreover, the definition of intra-prostatic tumor volume makes dose-painting radiotherapy technically feasible. In case of local relapse, local aggressive treatments are now routinely offered. In case of oligometastatic disease, irradiation occupies a growing place, which benefits directly from the best targeting offered by these new tracers.     

Les examens cardiaques en tomographie par émission de positons

Cardiac positron emission tomography (PET) is yet considered as a reference imaging technique but remains poorly used in clinical practice. At the present time, the advantages of cardiac PET investigations are far to be evident, when compared with conventional tomoscintigraphy (SPECT), except for perfusion imaging in the obese and for viability assessment in case of very severe cardiac dysfunction. However, this situation might quickly move because of an enhanced availability of PET imaging, dramatic technical progresses and promising new tracers. In particular, the last-generation PET-cameras allow reaching spatial resolutions and detection sensitivities, which are now spectacularly higher than those from conventional SPECT imaging. In addition, the list mode recording allows the subsequent images reconstruction to be synchronized to cardiac cycle but also to respiratory cycle; and the quantifications of myocardial perfusion flow and of coronary flow reserve are now available in clinical routine. Furthermore, new tracers labelled with fluorine-18 are under development, especially for perfusion investigations, and kinetics properties of these new tracers are dramatically enhanced when compared with current perfusion SPECT tracers.     

Imagerie moléculaire de la maladie de Parkinson : données actuelles

During the last years, knowledge and concepts concerning Parkinson's disease and other parkinsonian syndromes have progressed: a concept of network pathology with different clinical presentations and evolutions, involving several neurotransmission pathways succeeeded the single dopaminergic lesion concept. Imaging also changed with the development of MRI. In this context, the aim of this work is to bring up-to-date methodology and clinical contribution of dopaminergic neuron imaging. Nigrostriatal neuron imaging (dopamine transporter imaging) contributes to diagnosis of Parkinson's disease and Lewy body dementia. Dopamine receptor imaging mainly helps in differential diagnosis of parkinsonian syndromes (Parkinson's disease and Parkinson plus syndromes). The ongoing development of dopaminergic, cholinergic, serotoninergic tracers and the recent emergence of amyloid plaques and neurofibrillary tangles imaging open perspectives for molecular imaging and care of neurodegenerative diseases.     

Modalités du transport et du métabolisme de l'AIA 14C ou AIA 3H en relation avec la morphogenèse des bourgeons axillaires chez le Scrophularia arguta

Modes of transport and metabolism of ¹⁴ C-IAA and ³ H-IAA in relation to morphogenesis of axillary buds in Scrophularia arguta. The main objectives of this study were to investigate the morphogenetic role of IAA on the growth and development of axillary buds. After foliar applications of radioactive IAA for 6 h on intact plants of Scrophularia arguta Sol. the characteristics of auxin transport were studied by liquid scintillation counting, thin layer chromatography and microautoradiography. The main part of the radioactivity moved at a mean rate of 7 mm/h. Over long periods of transport, the tracers accumulated at the base of the axis and in the roots. The nodes were a little richer in ³H or ¹⁴C than the internodes. This fact seemed to be correlated with the vascular organization of this part of the stem. A very weak proportion of tracers was found in axillary buds. The radioactivity was to about 50% associated with the IAA molecule; the rest corresponded essentially to indolyl-4-acetyl-l-aspartic acid and indolyl-3-aldehyde. Tracers were mainly concentrated in the phloem along the whole axis and, to a lesser extent in some of the young differentiating metaxylem vessels, and in the medullary rays. No radioactivity was found in the cambial zone and in the mature xylem, nor in the parenchymas. These results support the view of an indirect role of IAA on the axillary bud growth and morphogenesis.     

Rôle de L'éthylène dans L'Accumulation de Capsidiol et la Sensibilité a Phytophthora capsici chez le Piment Traite par un Eliciteur

Role of ethylene in both the synthesis of capsidiol and the susceptibility to Phytophthora capsici of pepper treated with an elicitor With inoculated plants, there is a strong increase of ethylene, specially with Phyo 636. But, with plants inoculated and treated with G5 15 the quantities of ethylene are less important than with those ones inoculated and untreated with G5 15. After contamination (and only in this case), there is capsidiol synthesis as well wit h treated plants as with untreated ones, and the quantities are not significantly different. Generally, the level of induced resistance is higher wit h Phyo 636 (genetically resistant) than with Yolo Wonder (genetically susceptible). The adjunction of ethylene precursor (ACC) to G5 15 elicitor increases induced resistance with Yolo Wonder but decreases with Phyo 636: the inverse effect is observed when using ethylene inhibitor (AVG). It is suggested that, in the interaction Pepper—Phytophthora capsia, neither ethylene production nor capsidiol synthesis can be considered as biochemical tracers of induced resistance.     

Radio-anatomie de la prostate et du pelvis

Development and use of new tracers in tumoral prostatic exploration by nuclear medicine require specifying the pelvic anatomical knowledge. This article offers a reminder of the prostate–pelvic anatomy by studying CT-scanner and MRI to know the essential structures for the writing of the medical report.     

L'analogie et la représentation de l'art primitif à la fin du XIX siècle

In this paper, we will examine the foundations of Western representation of Paleolithic art at the end of the nineteenth century. Taking the period of 1864-1902 into account, we will prove the leading role of analogy between “modern primitive societies” and “prehistoric societies” in the very definition of “primitive art”. According to us, the representation of the “primitive artist” at that time was largely based in comparison between art which came from modern primitive societies living in Africa, Australia or America, and prehistoric art which was authenticated at about 1865. Through this examination, we will show the way in which analogy functions as a main category in the construction of scientific knowledge.     

Projections of Olfactory Bulbs and Non-Olfactory Telencephalic Structures in Amygdaloid Complex of the Turtle <Emphasis Type="Italic">Testudo horsfieldi</Emphasis>: A Study Using Anterograde Tracer Technique

To confirm the discrete character of projections of telencephalic olfactory and non-olfactory structures to the amygdaloid complex (AC) in the terrestrial turtle Testudo horsfieldi, a study was performed by the method of anterograde axonal transport of tracers (HRP, BDA). After a massive injection of the tracers into the main and accessory olfactory bulb, a dense accumulation of labeled fibers and terminals was found in ventral part of AC in the neuropil zones of nbam (J) and ncoam and very scanty—in nmam and ncam. After a massive injection of the tracers into non-olfactory telencephalic structures including dorsal cortex, pallidal enlargement, and ADVR, a very dense terminal field was observed in the dorsal AC part and a less dense one, with predominance of labeled fibers, in its ventral part. Local administration of the tracers separately into the dorsolateral (visual area) and the ventromedial (auditory-somatic area) parts of the ADVR allowed revealing discrete projections, respectively, to the laterocentral and mediocentral areas of the dorsal AC part with a relative overlapping in the central AC area. In all experiments, retrogradely labeled neurons in AC were also observed in zones of the corresponding bulbar and rostrotelencephalic projections. Thus, it has been shown that in the turtle AC there exist not only separation of direct olfactory and non-olfactory projections, but also discrete projections of different sensory areas of ADVR. Reciprocity of these connections is also confirmed. Organization of afferent olfactory and non-olfactory telencephalic connections in AC is similar in reptiles and in mammals.     

L’imagerie moléculaire de la démence : quels moyens pour répondre à quelles questions ?

Molecular imaging might address two different aspects of dementia management: the early and etiologic diagnosis of the neurodegenerative disease causing the troubles, and the follow-up and treatment evaluation of the disease. Tracers available for these different purposes target either specific processes, such as the presence of beta amyloid in the case of Alzheimer disease, or processes that relate to the global functional state of the brain. Benefits and disadvantages of these different tracers vary according to the function of the goals pursued.     

以标志物对长江上游漂流性鱼卵漂流方式的研究

2008年4月7日在长江上游重庆江津-珞璜31km的江段采用标志物对自然条件下大流量河流漂流性鱼卵的漂流方式进行模拟实验。结果显示在流量稳定的情况下, 在同一投放点投放的标志物的平均漂流速度具有显著差异, 标志物在河流中的漂流密度以高峰值和低峰值相间的方式出现, 高峰值随漂流时间的增加呈逐渐下降趋势。在水平方向上标志物的分布以主流水域的漂流密度高于缓流水域, 缓流水域未采集到标志物。采用传统产卵规模计算方法对标志物投放数量进行估算,各组的估算数量均小于实际投放数量, 估算数量的准确性随漂流时间的增加而降低, 总体估算数量为实际投放数量的16.6%。根据实验结果, 建议在长江上游鱼类产卵规模计算中引入时间系数以弥补随漂流时间的增加而引起的估算准确性降低。       

Application of Stable Isotope Tracers to Studies of Zooplankton Feeding,using the Rotifer <Emphasis Type="Italic">Brachionus calyciflorus</Emphasis> as an Example

We present a protocol and calculation methods for the determination of zooplankton ingestion and assimilation rates with stable isotope tracers. These methods have been developed from experiments with the rotifer Brachionus calyciflorus that had been fed ¹³C-labelled Scenedesmus obliquus. Stable isotope tracers offer the same advantages as radioisotopes. These include the possibility for direct and accurate quantification of ingestion and assimilation rates, short sample analysis times and low animal densities requirements. However, the use of stable isotope tracers requires relatively long sample preparation times and specialist equipment and is, thus, relatively costly for most laboratories. The application of stable isotope tracers in zooplankton feeding studies offers several advantages in comparison with radioisotopes. Firstly, they do not emit harmful radiation and can therefore be applied safely both in the laboratory and in the field. Secondly, the samples can be dried for safe storage and easy transportation. Thirdly, no aggressive chemicals are required for sample analysis.     

Imagerie scintigraphique de l’infection des prothèses de hanche et de genou

Despite preventive measures, joint infection is a rare but serious complication of surgery of hip or knee with a major psycho-socio-economic impact. Its diagnosis can be difficult and therefore requires further investigations. None of them has absolute diagnostic value. Only their association can give to the clinician a bundle of presumption. Among imaging techniques, isotopic tests can provide valuable assistance. Scintigraphy with radiolabeled leukocytes in an in vitro or in vivo manner remains the gold standard in association with bone scintigraphy with excellent diagnostic performances. Associated with hybrid imaging machine, it can guide the sampling, which alone, made under strict conditions, can confirm the diagnosis by isolating the microorganisms and determine the optimal patient management. The [¹⁸F]-FDG-PET seems a promising method but whose interpretation criteria need to be refined in order to evaluate clinical studies in a reproducible way. Finally, new PET tracers are being studied in order to increase specificity concerning the infection diagnosis in cases of complex musculoskeletal infection.     

Le gisement acheuléen de plein air de La Garde (Loire). Remarques sur une série lithique acheuléenne entre Rhône et Loire

The lithic assemblage of La Garde offers the opportunity to observe a Final Acheulean series located in the Loire department (south-east France). The site was probably a multi-activity place asking large tools and flakes, according to the strategies used by humans. Three main categories of large bifacial tools mainly made of flint can be described, with a triangular or oval shape and with a transversal cutting edge. These tools are more bifacial-tools than bifaces through the kind of shaping and the retouches on the cutting edges. The Levallois flaking is associated to various other types of knapping. The site, located along a small valley, suggests a human circulating between the Saône-Rhône corridor and the interior basins of the Massif Central Mountains. The Rhodanian corridor yielded little evidence of Acheulean settlements while in the Centre of France, they are numerous. La Garde proves that systematic prospecting in this area will permit in future to complete the map of the Acheulean occupations in south-east France.