Decoding the nexus:branched-chain amino acids and their connection with sleep,circadian rhythms,and cardiometabolic health

The sleep-wake cycle stands as an integrative process essential for sustaining optimal brain function and,either directly or indirectly,overall body health,encompassing metabolic and cardiovascular well-being.Given the heightened metabolic activity of the brain,there exists a considerable demand for nutrients in comparison to other organs.Among these,the branched-chain amino acids,comprising leucine,isoleucine,and valine,display distinctive significance,from their contribution to protein structure to their involvement in overall metabolism,especially in cerebral processes.Among the first amino acids that are released into circulation post-food intake,branched-chain amino acids assume a pivotal role in the regulation of protein synthesis,modulating insulin secretion and the amino acid sensing pathway of target of rapamycin.Branched-chain amino acids are key players in influencing the brain's uptake of monoamine precursors,competing for a shared transporter.Beyond their involvement in protein synthesis,these amino acids contribute to the metabolic cycles ofγ-aminobutyric acid and glutamate,as well as energy metabolism.Notably,they impact GABAergic neurons and the excitation/inhibition balance.The rhythmicity of branchedchain amino acids in plasma concentrations,observed over a 24-hour cycle and conserved in rodent models,is under circadian clock control.The mechanisms underlying those rhythms and the physiological consequences of their disruption are not fully understood.Disturbed sleep,obesity,diabetes,and cardiovascular diseases can elevate branched-chain amino acid concentrations or modify their oscillatory dynamics.The mechanisms driving these effects are currently the focal point of ongoing research efforts,since normalizing branched-chain amino acid levels has the ability to alleviate the severity of these pathologies.In this context,the Drosophila model,though underutilized,holds promise in shedding new light on these mechanisms.Initial findings indicate its potential to introduce novel concepts,particularly in elucidating the intricate connections between the circadian clock,sleep/wake,and metabolism.Consequently,the use and transport of branched-chain amino acids emerge as critical components and orchestrators in the web of interactions across multiple organs throughout the sleep/wake cycle.They could represent one of the so far elusive mechanisms connecting sleep patterns to metabolic and cardiovascular health,paving the way for potential therapeutic interventions.

数据挖掘与建模技术在食品嗅觉和味觉感知与情绪认知中的应用

随着食品嗅觉和味觉感官及情绪认知相关的科学技术水平的不断提升,越来越多的仪器分析方法和实验设备用于上述领域的研究。检测方法的多样化、全面化以及检测精度的提升,也伴随着风味感知相关数据规模的扩增。如何从食品风味仪器分析结果以及消费者的情绪认知行为相关研究中收集的大量数据中获得关键信息,并建立数据间的关联,越来越被研究人员所关注。食品领域的数据挖掘与建模技术是利用食品生产及流通过程中获得的大量数据,实时、准确地监控食品产业链的各个环节中的物理化学变化,并预测这些变化可能对消费者感官特征及情绪认知产生的影响。目前在食品嗅觉和味觉感知领域,数据挖掘与建模技术可为食品科研人员和消费者提供前所未有的洞察力和分析能力。本文在针对经典的机器学习方法中的有监督和无监督的数据挖掘与建模方法以及深度学习方法的基础上,对食品感官属性研究以及情绪认知方面的最新应用进展进行分析,并展望数据挖掘与建模技术在食品嗅觉和味觉感知领域的应用前景,助力食品行业的科技进步和产业升级。

常用的“静态”和动态感官描述方法综述

食品的感官特性已成为衡量食品品质的重要组成部分,感官特性的描述分析对于评价食品感官特性具有重要意义。目前常用的“静态”感官描述方法包括主要基于专家组的定量描述分析法和适用于专家或消费者的选择所有适合项法、所有适合项量化法等,以给产品总体感官特性进行画像。但由于饮食过程中食品的感官特性会随时间发生变化,以致“静态”感官描述方法不能完整准确地体现产品感官特性及细腻变化。因此,与时间结合的动态感官描述方法,如实时选择所有适合项法、时间强度法和实时感官主导法等能更准确完整地描述产品的感官特性,引起了人们的极大关注。本文对常见的几种“静态”和动态感官描述方法及其应用进行介绍,以期为国内产品感官特性的研究提供方法指导。

化学计量学在食品风味领域的应用进展

风味物质影响食品的感官属性及消费者选择,风味物质分析对食品质量改善以及新产品开发都至关重要。然而,风味物质数据庞杂、统计分析运用不恰当极大程度限制了该领域发展,因此,正确、合理地使用新型化学计量学方法,如人工智能算法获取有效信息,在该领域至关重要。近年来化学计量学方法广泛应用于食品研究中,除降维、分类与回归方法外,多种神经网络方法也在食品领域研究中兴起,但对其合理应用的归纳总结较少。因此,本文对可用于研究食品风味的统计分析方法进行归纳总结,包括主成分分析和线性判别分析,线性回归方法如偏最小二乘回归系列,及非线性方法如模糊逻辑、人工神经网络等多种神经网络方法,对其原理进行讲解并进行应用举例,旨在为化学计量学在后续食品风味领域的研究提供有效的方法和思路。

GC-MS结合基于表情符号的消费者测评分析冷萃与热萃咖啡风味特征

为研究不同萃取温度的咖啡萃取液的香气差异及感官评价与香气物质之间的相关性,以3种商业冷萃咖啡和3种商业热萃咖啡为样品,通过基于表情符号的勾选所有适合项法进行香气感官评价,同时结合顶空固相微萃取-气相色谱-质谱联用技术对咖啡萃取液的香气成分进行测定,分析冷萃咖啡和热萃咖啡挥发性成分差异。结果表明:6种不同的咖啡萃取液共鉴定出93种挥发性成分,其中冷萃咖啡样品中大多数挥发性化合物含量高于热萃咖啡样品;在香气感官评价上,受试者对冷萃咖啡的整体喜好度高于热萃咖啡,受试者主要选择积极的表情符号来描述冷萃咖啡,而选择消极的表情符号描述热萃咖啡。基于表情符号的勾选所有适合项法通过表情符号使消费者表达了他们与不同咖啡萃取液相关的情绪,有助于更全面地了解消费者对产品的可接受性和理解消费者的产品体验。吡嗪类、呋喃类、醛类、酸类、酯类、酮类和醇类化合物赋予了冷萃咖啡坚果香、焦糖香、甜香和花香,使冷萃咖啡在风味上更胜一筹;热萃咖啡中的吡啶类、吡咯类和酚类化合物使热萃咖啡更偏向于木香、谷物香和烤香,具有一定的熏感和辛辣味。研究为探索冷萃咖啡与热萃咖啡萃取液的香气品质提供了数据参考,希望为冷萃咖啡与热萃咖啡的研究开发、改进与应用提供理论依据。

Vibrations induced by tunnel boring machine in urban areas: In situ measurements and methodology of analysis

Excavation with tunnel boring machine(TBM)can generate vibrations,causing damages to neighbouring buildings and disturbing the residents or the equipment.This problem is particularly challenging in urban areas,where TBMs are increasingly large in diameter and shallow in depth.In response to this problem,four experimental campaigns were carried out in different geotechnical contexts in France.The vibration measurements were acquired on the surface and inside the TBMs.These measurements are also complemented by few data in the literature.An original methodology of signal processing is pro-posed to characterize the amplitude of the particle velocities,as well as the frequency content of the signals to highlight the most energetic bands.The levels of vibrations are also compared with the thresholds existing in various European regulations concerning the impact on neighbouring structures and the disturbance to local residents.

Differential transcriptional regulation of the NANOG gene in chicken primordial germ cells and embryonic stem cells

Background:NANOG is a core transcription factor(TF)in embryonic stem cells(ESCs)and primordial germ cells(PGCs).Regulation of the NANOG gene by TFs,epigenetic factors,and autoregulatory factors is well characterized in ESCs,and transcriptional regulation of NANOG is well established in these cells.Although NANOG plays a key role in germ cells,the molecular mechanism underlying its transcriptional regulation in PGCs has not been studied.Therefore,we investigated the mechanism that regulates transcription of the chicken NANOG(cNANOG)gene in PGCs and ESCs.Results:We first identified the transcription start site of cNANOG by 5′-rapid amplification of cDNA ends PCR analysis.Then,we measured the promoter activity of various 5′flanking regions of cNANOG in chicken PGCs and ESCs using the luciferase reporter assay.cNANOG expression required transcriptional regulatory elements,which were positively regulated by POU5F3(OCT4)and SOX2 and negatively regulated by TP53 in PGCs.The proximal region of the cNANOG promoter contains a positive transcriptional regulatory element(CCAAT/enhancer-binding protein(CEBP)-binding site)in ESCs.Furthermore,small interfering RNA-mediated knockdown demonstrated that POU5F3,SOX2,and CEBP played a role in cell type-specific transcription of cNANOG.Conclusions:We show for the first time that different trans-regulatory elements control transcription of cNANOG in a cell type-specific manner.This finding might help to elucidate the mechanism that regulates cNANOG expression in PGCs and ESCs.

Predictors of Clostridium difficile infection severity in patients hospitalised in medical intensive care

AIM:To describe and analyse factors associated with Clostridium difficile infection(CDI)severity in hospitalised medical intensive care unit patients.METHODS:We performed a retrospective cohort study of 40 patients with CDI in a medical intensive care unit(MICU)at a French university hospital.We include patients hospitalised between January 1,2007and December 31,2011.Data on demographics characteristics,past medical history,CDI description was collected.Exposure to risk factors associated with CDI within 8 wk before CDI was recorded,including previous hospitalisation,nursing home residency,antibiotics,antisecretory drugs,and surgical procedures.RESULTS:All included cases had their first episode of CDI.The mean incidence rate was 12.94 cases/1000admitted patients,and 14.93,8.52,13.24,19.70,and8.31 respectively per 1000 admitted patients annually from 2007 to 2011.Median age was 62.9[interquartile range(IQR)55.4-72.40]years,and 13(32.5%)were women.Median length of MICU stay was 14.0d(IQR 5.0-22.8).In addition to diarrhoea,the clinical symptoms of CDI were fever(>38℃)in 23 patients,abdominal pain in 15 patients,and ileus in 1 patient.The duration of diarrhoea was 13.0(8.0-19.5)d.In addition to diarrhoea,the clinical symptoms of CDI were fever(>38℃)in 23 patients,abdominal pain in 15 patients,and ileus in 1 patient.Prior to CDI,38patients(95.0%)were exposed to antibiotics,and 12(30%)received at least 4 antibiotics.Fluoroquinolones,3rdgeneration cephalosporins,coamoxiclav and tazocillin were prescribed most frequently(65%,55%,40%and 37.5%,respectively).The majority of cases were hospital-acquired(n=36,90%),with 5 cases(13.9%)being MICU-acquired.Fifteen patients had severe CDI.The crude mortality rate within 30 d after diagnosis was 40%(n=16),with 9 deaths(9 over 16;56.3%)related to CDI.Of our 40 patients,15(37.5%)had severe CDI.Multivariate logistic regression showed that male gender[odds ratio(OR):8.45;95%CI:1.06-67.16,P=0.044],rising serum C-reactive protein levels(OR=1.11;95%CI:1.02-1.21,P=0.021),and previous exposure to fluoroquinolones(OR=9.29;95%CI:1.16-74.284,P=0.036)were independently associated with severe CDI.CONCLUSION:We report predictors of severe CDI not dependent on time of assessment.Such factors could help in the development of a quantitative score in ICU’s patients.

Artificial Neural Network Modeling of Healthy Risk Level Induced by Aircraft Pollutant Impacts around Soekarno Hatta International Airport

Aircraft pollutant emissions are an important part of sources of pollution that directly or indirectly affect human health and ecosystems. This research suggests an Artificial Neural Network model to determine the healthy risk level around Soekarno Hatta International Airport-Cengkareng Indonesia. This ANN modeling is a flexible method, which enables to recognize highly complex non-linear correlations. The network was trained with real measurement data and updated with new measurements, enhancing its quality and making it the ideal method for this research. Measurements of aircraft pollutant emissions are carried out with the aim to be used as input data and to validate the developed model. The obtained results concerned the improved ANN architecture model based on pollutant emissions as input variables. ANN model processes variables—hidden layers—and gives an output variable corresponding to a healthy risk level. This model is characterized by a 4-10-1 scheme. Based on ANN criteria, the best validation performance is achieved at epoch 28 from 34 epochs with the Mean Squared Error (MSE) of 9 × 10-3. The correlation between targets and outputs is confirmed. It validated a close relationship between targets and outputs. The network output errors value approaches zero. Further research is needed with the aim to enlarge the scheme of the ANN model by increasing its input variables. This is one of the major key defining environmental capacities of an airport that should be applied by Indonesian airport authorities. These would institute policies to manage or reduce pollutant emissions considering population and income growth to be socially positive.

Ⅱ型糖尿病患者微粒体甘油三酯转移蛋白基因多态性与肝脂肪变生物学表征间的联系

非酒精性脂肪肝(NASH)指在组织学上与酒精性肝脏疾病相似,但患者无过量使用酒精史. 诊断NASH有两个必需的组织学标准:脂肪变性和炎症或纤维化.后一条标准把NASH与单纯脂肪肝区别开来.在西方国家,NASH是肝脏酶学升高的主要原因,仅次于饮酒和丙型肝炎.它与肥胖(40%)、Ⅱ型糖尿病(20%)、高脂血症(20%)有关,最终有多达20%～30%的NASH 患者可发生肝硬化.NASH的发生可能需要经过两个过程.第一个过程导致肝脂肪变性,第二个过程是由脂肪变性变为NASH.可能导致NASH发生的因素包括:①胰岛素抵抗、异常脂肪酸代谢和肝内甘油三酯沉积等代谢紊乱;②氧化张力升高;③细胞因子产量增加.

The IMPAQT Project:Reflections on a Participatory Research Mechanism

Over the last forty years,many methodologies have been initiated within the framework of the participatory approach,the objective of which is to encourage the involvement of citizens in the definition and implementation of projects and policies concerning them.The implementation of these participatory approaches in the field of interventional research in population health reveals several scientific,organizational,inter-individual,and ethical issues that must be discussed.Thus,we propose to present here the fruit of a collective reflection of the members of a research group,composed of patient-researchers and researchers in social psychology,on the implementation of the IMPAQT research project,which aimed to promote a community-based research approach in oncology.The discussion will be structured around three topics:the implementation of the participatory research mechanism,the sustainability of the commitment involved in participating in research,and the valorization of the participation of the patient-researchers.These issues are particularly important to consider in guiding the implementation of a solid and balanced partnership with those concerned in the co-construction of interventional research devices in cancerology.

Review of source-monitoring processes in obsessive-compulsive disorder

Obsessive-compulsive disorder(OCD)is a severe mental illness characterized by persistent,intrusive and distressing obsessions and/or compulsions.Such symptoms have been conceptualized as resulting from a failure in sourcemonitoring processes,suggesting that patients with OCD fail to distinguish actions they perform from those they just imagine doing.In this study,we aimed to provide an updated and exhaustive review of the literature examining the relationship between source-monitoring and OCD.A systematic search in the literature through January 2019 allowed us to identify 13 relevant publications investigating source-monitoring abilities in patients with OCD or participants with subclinical compulsive symptoms.Most of the retrieved studies did not report any source-monitoring deficits in clinical and subclinical subjects compared with healthy volunteers.However,most of the studies reported that patients with OCD and subclinical subjects displayed reduced confidence in source-monitoring judgments or global cognitive confidence compared to controls.The present review highlighted some methodological and statistical limitations.Consequently,further studies are needed to explore source monitoring with regard to the subcategories of OCD symptoms(i.e.,symmetryordering,contamination-washing,hoarding,aggressive obsession-checking,sexual-religious thoughts)and to clarify the relationship between sourcemonitoring subtypes(i.e.,reality or internal source-monitoring)and confidence in these populations.

EVOLUTION OF THE BLOOD INTERFACE USING AN AUTOLOGOUS VENOUS PATCH TO CORRECT AN AORTIC DEFECT IN RATS

In order to investigate the evolution of the venous patch blood inter face after implantation, an experimental model utilizing an autologous venous patch to repair an infrarenal abdominal aortic defect in rats was developed. A small piece of both the jugular vein and the aorta were first excised. After implantation and reestablishment of blood flow, the animals were subsequently sacrificed in groups of 3 at the following intervals: 10 seconds, 1, 10, 30 minutes, 1, 6, 12, 24 hours, 7, 30 and 90 days. All the patches and adjacent aortae were collected and studied using scanning electron microscopy. The results of our present show that: 1) the extensive endothelial lesion of both the autologous vein patch and the adjacent aorta is presented before implantation due to operative manipulation; 2) after blood flow reestablishment, the patch and the adjacent aortic interface are reactive to platelets and other blood cells; 3) the new cellular lining begins to appear from the 7th day after implantation, but it is not complete at 3 months; 4)from the model, the endothelial repair of autologous venous patch and its adjacent aorta is a very slow process.

Preliminary Results of DHEA in Poor Responders in IVF

Objective: Dehydroepiandrosterone (DHEA) has been previously reported to improve ovarian response in IVF for poor responders. Its effect remains uncertain. The purpose of this study was to evaluate the effect of DHEA given during two years in our unit, in order to build hypothesis for a future randomized controlled trial. Design: Cohort of exposed and non-exposed DHEA study. Patient(s): 224 patients with AMH under 1.6 ng/ml undergoing IVF with a short antagonist protocol adding FSH and LH rec were enrolled for 327 IVF cycles. 176 patients had been treated with DHEA before IVF, and 151 had not. Intervention(s): None. Main Outcome Measure(s): Cancellation cycle rate, amount of gonadotrophins used, estradiol level on day six of stimulation, number of oocytes retrieved, metaphase II oocytes, blastocysts and frozen embryos, clinical pregnancy rate and miscarriage rate. Results: The cancellation rate was significantly higher in the group without DHEA (29.8% versus 13.1%, p = 0.002). The amount of gonadotrophins used for stimulation, the estradiol level on day six of stimulation, the number of oocytes retrieved, metaphase II oocytes, blastocysts, frozen embryos and miscarriage rate were not different in both groups. The clinical pregnancy rate per included patient in the DHEA group was 17.1% versus 8.6% in the non-treated group (p = 0.02). Conclusion: DHEA appears to improve clinical pregnancy rate by decreasing the cancellation rate.

Recurrent hyphema after trabeculectomy: an atypical case of Swan syndrome

Dear Editor,Trabeculectomy is the gold standard surgery for treatment of glaucoma. Early complications include wound leaks, responsible for ocular hypotony and serous choroidal detachment, and bleb fibrosis. Postoperative hyphema is also a well-known complication, most frequently induced by iris bleeding from the peripheral iridotomy. In most cases, bleeding occurs in the first months after surgery.

Predictive Factors for Persistent Pain and Poor Recovery of Health Status 1 Year after Whiplash Injury (Quebec Grade 1 and 2): Results from the ESPARR Cohort

Background: A large number of studies have addressed whiplash injury, and many meta-analyses have sought to highlight chronicity factors;the implicated processes, however, remain a matter of debate. The present study used data from the ESPARR cohort (an on-going prospective study of a representative cohort of road accident victims in the Rh?ne administrative département of France). The objectives were to describe the consequences of whiplash injury and to determine prognostic factors for poor recovery and persistent pain at 1 year post-accident. Methods: The cohort included 255 “pure” whiplash victims, 173 of whom responded to the 1-year follow-up questionnaire. Correlations between explanatory variables and health and pain status were explored by modified Poisson regression to provide adjusted relative risk (RR) values. Results: Half of the victims had not fully recovered health status by 1 year. The main factor associated with non-recovery was pain (RR = 1.3;1.0-1.7). A birth in the family preceding the accident emerged as another factor (RR=1.5;1.2-1.9). Victims responsible for their accident were twice as likely to report being free of pain as those not responsible (RR = 0.5;0.3-0.8). No correlation emerged with accident-related characteristics or PTSD. Conclusions: The present results extend our understand- ing of whiplash injury. Residual pain is the fundamental factor causing whiplash victims to feel that they have not recovered good health. Our findings suggest this may be bound up with physical factors (gender susceptibility);external factors such as having to carry weights (such as a baby) and with perceiving oneself as a victim are not incompatible with this hypothesis.

Is There a Specific Profile of COVID-19 Risk Perception among People with Cancer?A Cross-Sectional Study

Aims:This study aimed to determine if people with cancer(PWC)exhibit a unique COVID-19 risk perception profile and identify psychosocial factors characterizing PWC who do not conform to the majority risk perception profile.Procedure:A cross-sectional online self-questionnaire study was conducted in France from April 25 to May 07,2020,with a sample(n=748)comprising PWC,individuals not currently receiving cancer treatment,and those without a history of cancer.Latent profiles of COVID-19 risk perception(PCRP)were established.Methods:A multivariate multinomial logistic regression was performed to assess the association between cancer status and PCRP membership.Characteristics of PWC across different profiles were compared.Results:Four profiles emerged,ranging from Low-Risk to High-Risk Perceivers.PWC were more likely to belong to the High-Risk Perceivers profile(aOR:3.02;p<0.001).PWC not conforming to this profile had a higher perceived socioeconomic level(PSL)(p<0.05).The majority of PWC demonstrated a specific COVID-19 risk perception profile,mainly influenced by medical knowledge linking cancer to increased COVID-19 severity.PSL was a key determinant in shaping risk perception among PWC.Conclusion:Interventions targeting COVID-19 risk perception modification should consider these factors,with particular emphasis on addressing concerns related to SARS-CoV-2 infection.

AB014.Impaired anti-saccade production in posterior parietal cortex damaged patients

Background:Performing an anti-saccade relies on two mechanisms:(I)inhibiting an automatic saccade to a target,and(II)generating,instead,a voluntary saccade to a location other than this visual target.It remains unclear where and how these two processes are implemented to ensure the production of correct anti-saccades.Previous research in optic ataxia has implicated the posterior parietal cortex(PPC)in anti-pointing,implying a possible role of the PPC in anti-saccade production.Methods:Here,we tested how three patients with unilateral or bilateral damage to the PPC,as well as six neurologically intact controls,perform different types of anti-saccade:classic anti-saccades(180°rotation)or mirror saccades(90°rotation)across and within hemi-fields.Results:We showed that PPC damaged patients were impaired in anti-saccade production for their contralesional visual fields.This was reflected in a longer period of erroneous pro-saccades,longer latencies associated with correct anti-saccades to the contralesional visual field and more imprecise anti-saccades.Conclusions:Our results thus suggest that PPC damage results in delayed and prolonged competing saccade planning processes between two locations(i.e.,visual target and saccade goal location).Taken together,our results provide evidence for a crucial role of the PPC in parallel mechanisms underlying anti-saccade performance.

AB011.Reliance on central vs.peripheral vision for visual search in younger and older adults

Background:It has been suggested that older adults show a reduced attentional field compared to younger adults.This may be attributed to a poorer utilization of peripheral vision(i.e.,peripheral attentional allocation)and a higher reliance on central vision compared to younger adults.To test this,we examined the importance of central,peri-foveal and near periphery information in younger and older adults by comparing their visual search performance while their central vision was blocked,in the presence of different sized artificial central scotomas.We tested participants in two versions of visual search,pop-out and serial search,because they require a different use of central and peripheral attention.Pop-out search relies on processing of the entire visual scene(i.e.,global processing)whereas serial search requires processing of each feature serially(i.e.,local processing).Methods:Thirteen healthy younger(M=21.8,SD=1.5)and 15 older adults(M=69.1 years,SD=7.3)performed a pop-out and a serial version of a visual search task in the presence of different sized gaze-contingent artificial central scotomas(no scotoma,3°diameter,5°and 7°).Participants were asked to indicate as quickly as possible whether a target was present or not among distractors whose number varied(16,32 or 64 objects).Results:We found evidence for a greater decline in peripheral processing in older adults compared to younger in pop-out but not in serial search.For the pop-out condition with no scotoma,we found that the further the target in the periphery,the longer the search time,and that this increase was proportionally greater for older adults compared to younger adults.Further,increases in scotoma size were associated with a greater increase in reaction times for older adults compared to younger participants.For the serial condition,both groups showed similar increases in reaction times with target distance from center and scotoma size.We surmise that this may be due to task difficulty in serial search;central vision is necessary for both groups.Conclusions:In conclusion,these findings suggest that,in global processing,older adults distribute more resources towards central vision compared to younger adults.

FDG-PET可提高神经系统副肿瘤综合征患者的肿瘤检出率

To determine the usefulness of [18F]fluorodeoxyglucose (FDG) whole body FDG PET in the diagnosis of tumours in patients with paraneoplastic neurological syn dromes (PNS) , we prospectively studied 20 patients with paraneoplastic antibod ies in whom conventional imaging gave negative or inconclusive results for the p resence of tumour. All 20 patients had neurological manifestations compatible wi th PNS and well characterized paraneoplastic antibodies (12 anti Hu, one anti Hu and anti CV2, one anti CV2, four anti Yo, one anti Ri and one anti amp hiphysin). The mean delay between the onset of neurological symptoms and FDG PE T was 10 months (range 1-54). In these 20 patients, abnormal uptake was demonst rated in 18 patients, with some patients having abnormal signal in several areas . We observed abnormal uptake in the mediastinum (13 cases), lung (two cases), b reast (two cases), parotid gland (one case), or the cervical, supra clavicular or axillary lymph nodes (seven cases). Following FDG PET, the histological diag nosis of the tumour was made in 14 patients (small cell lung carcinoma in eight cases, breast adenocarcinoma in two, lung adenocarcinoma in two, axillary metast asis of ovary carcinoma in one, and malignant thymoma in one). Two other patient s with abnormal FDG uptake showed radiological evidence of lung cancer, but a hi stological diagnosis could not be obtained. In two other patients, initial FDG PET showed abnormal FDG uptake that was not confirmed a few months later by repe at FDG PET. In the two patients with negative FDG PET, peritoneal carcinomatos is was diagnosed in one and no tumour was found in the other. In our series, the sensitivity of FDG PET for tumour detection was >83%demonstrating a clear rol e of this technique in the management of patients with PNS. However, in our seri es, the specificity of FDG uptake was only 25%due to unexplained abnormal FDG u ptake in three patients and in abnormal FDG uptake due to a benign tumour in one patient. Over the study period, we saw 73 other patients with PNS and paraneopl astic antibodies. A tumour was demonstrated in 71 out of 73 by conventional tech niques. Since false positive and false negative results are possible with FDG PET and in most patients with PNS, the tumour is demonstrated by conventional techniques, we believe that FDG PET should be reserved, at the moment, for pati ents with well defined PNS antibodies when conventional imaging fails to identi fy a tumour or when lesions are difficult to biopsy.