Instantons and the Path to Intermittency in Turbulent Flows

Processes leading to anomalous fluctuations in turbulent flows, referred to as intermittency, are still challenging. We consider cascade trajectories through scales as realizations of a stochastic Langevin process for which multiplicative noise is an intrinsic feature of the turbulent state. The trajectories are conditioned on their entropy exchange. Such selected trajectories concentrate around an optimal path, called instanton, which is the minimum of an effective action. The action is derived from the Langevin equation, estimated from measured data. In particular instantons with negative entropy pinpoint the trajectories responsible for the emergence of non-Gaussian statistics at small scales.

PRRSV detection by qPCR in processing fluids and serum samples collected in a positive stable breeding herd following mass vaccination of sows with a modified live vaccine

In the last two decades, in France, Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) stabilization protocols have been implemented using mass vaccination with a modified live vaccine (MLV), herd closure and biosecurity measures. Efficient surveillance for PRRSV is essential for generating evidence of absence of viral replication and transmission in pigs. The use of processing fluid (PF) was first described in 2018 in the United States and was demonstrated to provide a higher herd-level sensitivity compared with blood samples (BS) for PRRSV monitoring. In the meantime, data on vertical transmission of MLV viruses are rare even as it is a major concern. Therefore, veterinarians usually wait for several weeks after a sow mass vaccination before starting a stability monitoring. This clinical study was conducted in a PRRSV-stable commercial 1000-sow breed-to-wean farm. This farm suffered from a PRRS outbreak in January 2018. After implementing a stabilisation protocol, this farm was controlled as stable for more than 9 months before the beginning of the study. PF and BS at weaning were collected in four consecutive batches born after a booster sow mass MLV vaccination. We failed to detect PRRSV by qPCR on PF and BS collected in a positive-stable breeding herd after vaccination with ReproCyc® PRRS EU (Boehringer Ingelheim, Ingelheim, Germany).

[Can positron emission tomography assessment of response to treatment help to individualize use of erlotinib in non-small cell lung cancer?]

Erlotinib can be prescribed in the treatment of locally advanced or metastatic non-small lung cancer cell (NSCLC) after failure of at least one prior chemotherapy regimen on the basis of the BR-21 study. Several publications have recently questioned these results. The metabolic imaging of solid tumours by positron emission tomography is a research field that could help customize the treatment of NSCLC and so complement the treatment approaches allowed by genetic analyses. This strategy is part of an innovative "early metabolic look" approach. The primary objective of this study is to determine if metabolic progression observed between the 7th and 14th day after initiation of treatment with erlotinib by 3'-Deoxy-3'-[18F]-Fluorothymidine PET in patients with EGFR naive NSCLC is predictive for morphological progression after 6 to 8 weeks of treatment. A health economic analysis will be conducted. This study is particularly innovative because it begins the exploration of the era of metabolic evaluation of therapeutic response in NSCLC.

Abstract P4-01-05: 3’-deoxy-3’-[18F]fluoro-thymidine (18F-FLT) positron emission tomography (PET): An accurate and effective tool for assessing tumor response in breast cancer

Objectives : A French multicenter study was promoted by the national French cancer federation (Unicancer R&D) to assess the potential of [18F]FLT (positron emission tomography (PET) biomarker of proliferation)to manage breast cancer neoadjuvant chemotherapy (NAC). The main objective was to compare changes in tumor [18F]FLT uptake to histopathological changes induced by NAC, assuming an arrest of tumor growth related to the effectiveness of NAC.

Methods : 97 patients (age 48.6 +/- 10.2 y.) were included in 13 nuclear medicine centers. All patients were eligible to anthracycline-based NAC for a de novo unifocal breast cancer (ductal n = 84, lobular = 11, other type = 2; stage II n = 75, stage III n = 21 et stage IV n = 1). 90 patients underwent a baseline PET before the onset of NAC (PET1) and a final PET after the end of NAC and before surgery (PET3). PET acquisitions were performed 60±7min after FLT injection. SUVmax (maximum standardized uptake value), SUVpeak (1 cm3 ROI including pixel max) and SUV41 (isocontour 41% of pixel max) were computed. Changes in SUV on PET3 vs PET1 were analyzed in relation to histopathological findings at the end of NAC (Sataloff criteria).

Results : Tumor FLT uptake decreased markedly between TEP1 and TEP3 (SUVmax = 6.2±4.8 vs 1.3±1.2 respectively; SUVpeak = 4.6±3.2 vs 0.9±0.9; SUV41 = 3.6±2.8 vs 0.8±0.7). Total or near-total therapeutic effect (grade A) were obtained in 20 patients, more than 50% therapeutic effect but less than total or near-total effect (grade B) in 37 patients, less than 50% therapeutic effect but visible effect (grade C) in 22 patients, or no therapeutic effect (grade D) in 11 patients. SUVmax decreased dramatically (87.5%) to background levels in all patients with a complete response (grade A). Overall, changes in SUV differed depending on the type of histological response (p<0.01) i.e. SUVmax changes were more pronounced as pathological responses were good: 61% for grade D; 65.7% grade C and 69.8% grade B. The same results were obtained with the two other SUV types.

Conclusions : Pathologic response to NAC in breast cancer can be assessed accurately by FLT.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-01-05.

A starch-based microparticulate system dedicated to diagnostic and therapeutic nuclear medicine applications

The aim of this work was to develop a new microparticulate system able to form a complex with radionuclides with a high yield of purity for diagnostic or therapeutic applications. Owing to its properties potato starch was chosen as starting material and modified by oxidization and coupling of a ligand (polyamine) enabling modified starch to chelate radionuclides. The choice of suitable experiments was based on a combination of a Rechtschaffner experimental design and a surface response design to determine the influence of experimental parameters and to optimize the final product. Starch-based microparticle formulations from the experimental plans were compared and characterized through particle size analysis, scanning electron microscopy, elemental analysis and, for the most promising formulations, by in vitro labeling stability studies and determination of free polyamine content or in vivo imaging studies. The mechanism of starch-based microparticle degradation was identified by means of size measurements. The results of the Rechtschaffner design showed the positive qualitative effect of the temperature and the duration of coupling reaction whereas surface response analysis clearly showed that, by increasing the oxidization level and starch concentration, the nitrogen content in the final product is increased. In vitro and in vivo characterization led to identification of the best formulation. With a size around 30 μm, high radiochemical purity (over 95%) and a high signal-to-noise ratio (over 600), the new starch-based microparticulate system could be prepared as ready-to-use kits and sterilized without modification of its characteristics, and thus meet the requirement for in vivo diagnostic and therapeutic applications.

Feedback modulates gamma oscillations in a hypothesis testing paradigm

We analyzed the time-varying modulation of gamma (>30 Hz) electroencephalographic (EEG) activity exerted by positive and negative feedback in a hypothesis testing paradigm. Ten college students serially tested hypotheses concerning a hidden rule by judging its presence or absence in triplets of digits and revised them on the basis of an exogenous performance feedback. The EEG signal was convolved with a family of complex wavelets and brain potentials were extracted in the gamma range. Feedback-related modulations were found as early as 100 ms after feedback onset, as well as in the 300-600 ms time-window. The results were discussed in terms of functional and neurophysiological models of feedback.

Modulation of late alpha band oscillations by feedback in a hypothesis testing paradigm

We used the electroencephalogram (EEG) to investigate whether positive and negative performance feedbacks differentially modulate late time-locked oscillatory brain activity in hypothesis testing. Ten college students serially tested hypotheses concerning a hidden rule by judging its presence or absence in triplets of digits, and revised them on the basis of an exogenous performance feedback. The EEG signal was convolved with a family of complex wavelets and induced brain potentials were extracted in the alpha range (8-13 Hz). The time-varying modulation of alpha activity time-locked to positive and negative feedback was analyzed in the 350-700 ms time-window. The results showed differential feedback-induced modulations of upper-alpha rhythms (> or =10 Hz) between 450 and 700 ms in parieto-occipital and central regions, and of lower-alpha rhythms (<10 Hz) between 350 and 450 ms in central regions. These results were interpreted in terms of differential functional roles of feedback in short-term memory and active inhibition/disinhibition of resources for subsequent hypothesis testing. Some implications for cognitive models of feedback are discussed.

Time-frequency intracranial source localization of feedback-related EEG activity in hypothesis testing

The neural correlates of the response to performance feedback have been the object of numerous neuroimaging studies. However, the precise timing and functional meaning of the resulting activations are poorly understood. We studied the electroencephalographic response time locked to positive and negative performance feedback in a hypothesis testing paradigm. The signal was convoluted with a family of complex wavelets. Intracranial sources of activity at various narrow-band frequencies were estimated in the 100- to 400-ms time window following feedback onset. Positive and negative feedback were associated to 1) early parahippocampo-cingular sources of alpha oscillations, more posteriorly located and long lasting for negative feedback and to 2) late partially overlapping neural circuits comprising regions in prefrontal, cingular, and temporal cortices but operating at feedback-specific latencies and frequencies. The results were interpreted in the light of neurophysiological models of feedback and were used to discuss methodological issues in the study of high-level cognitive functions, including reasoning and decision making.

Lésions mammaires impalpables et macrobiopsies stéréotaxiques avec le Mammotome® 11 G : faut-il opérer après diagnostic d’hyperplasie canalaire atypique ?

Atypical ductal hyperplasia (ADH) of the breast is a difficult histologic diagnosis. It is usually found, but not always, on clusters of microcalcifications. The subsequent risk of breast carcinoma is 4 to 5 times more important and the carcinoma can arise in the same breast or in the contralateral breast. Diagnosis can be establish on core needle biopsy with Mammotome 11G. The risk of under-estimation (ductal carcinoma in situ or invasive carcinoma) is about 20%. This risk is drastically decreased if the target (the calcifications) is completely removed by the Mammotome. This study includes 62 cases of ADH found on 633 calcifications biopsied by Mammotome 11G. In 31 cases, surgery was performed and ADH was confirmed in 25 cases (6 cases was under-estimated). In the other 31 cases, all calcifications were removed, there was no other risk factor and follow-up was suggested. Like after surgery, yearly bilateral mammography during about 20 years is recommended. In this last group, there was no false-negative result, median follow-up: 35,5 months (22-62).

[Palaeoparasitological study of atypical elements of the low and High Nile Valley]

Paleoparasitology in the Old World has mainly concerned the study of latrine sediments and coprolites collected from mummified bodies or archaeological strata, mostly preserved by natural conditions. For the first time, different unusual archaeological samples were studied to look for the eggs of helminths parasites (embalming reject jar, canopic package, shroud). Now, samples of organic matter have been successfully processed in order to extract helminths eggs, following the protocol of BOUCHET 2001 (4). Helminth eggs are frequently preserved in the late Quaternary archaeological contexts because of their hard-wearing chitin shell. Six types of eggs were revealed (Schistosoma mansoni, Schistosoma haematobium, Taenia, Enterobius vermicularis, Ascaris lumbricoides and Trichuris trichiura). This study allows to enlarge the Palaeoparasitological research with material never exploited. Moreover, if we take into account identified parasite and geography, it's possible to enlarge the debate to parasite spatio-temporal migration. Considering the particular context of samples preservation, it's interesting to observe an exceptional conservation of parasitological sign related to excellent taphonomic condition (aridity anaeroby, rapid interruption of thanatomorphosis, natural "mummification").

Les opacités et les microcalcifications de la classification ACR 3 liées à un cancer

At screening mammography, lesions must be assigned to BI-RADS classification. Category 3 is used for nonpalpable probably benign lesions. This category is defined either by a subset of lesions that are so likely to be benign that follow-up is a reasonable alternative to immediate biopsy, or by a less than 2% malignancy rate for American BI-RADS, or than 5% for French ANAES. The initial work-up to analyze the lesion must be complete, not only with four screening standard views but with magnification views and sonography if necessary. The risk of malignancy is very low and the pronostic factors are the same as in screening detected carcinomas.

Dioctophymidae eggs in coprolites from Neolithic site of Arbon-Bleiche 3 (Switzerland)

Dioctophymidae eggs were found in human coprolites dated from 3,384 to 3,370 BC from the site Arbon-Bleiche 3, Switzerland. This is the first record of dioctophymiasis in archaeological material. The important percentage of this disease in the studied coprolites raises the question of a higher prevalence during the Neolithic than at present.

[Spleno-gonadal fusion: differential diagnosis of a testicular tumor in an infant]

The authors report the case of a one-year-old infant in whom routine examination by the paediatrician demonstrated left testicular swelling. Subsequent assessment (scrotal ultrasound and laboratory tests) revealed only a moderate increase of alpha-foetoprotein levels. Orchidectomy was performed due to a suspicion of vitelline tumour. Histological examination revealed splenogonadal fusion. In the light of this case, the authors discuss the modalities of early diagnosis of this embryonic anomaly for which orchidectomy appears to be excessive, even when the testicular parenchyma has an immature appearance.

Crab louse infestation in pre-Columbian America

Until now, Pthirus pubis infestation in ancient human populations had only been recorded in the Old World. We found crab lice on South American mummified bodies from the Atacama Desert region. Crab louse eggs were found attached to the pubic hairs of a 2,000-yr-old Chilean mummy. Well-preserved adults were found in sediment and clothing from a Peruvian mummy dated 1,000 yr ago. Paleoparasitological evidence expands the knowledge of the distribution of this ectoparasite in ancient populations. As with many other parasites, pubic lice recorded in Andean populations show the antiquity of this parasite in the New World. It is likely that P. pubis entered the continent with early human migration to the New World.

[Stereotactic 11-gauge directional vacuum-assisted breast biopsy: experience with 249 patients]

PURPOSE

To assess the value of percutaneous vacuum-assisted core biopsy to improve the diagnosis of non palpable mammographic abnormalities.

MATERIALS AND METHODS

A total of 252 core biopsies using an 11G Mammotome((R))were performed in 249 patients. Stereotactic localization was performed in the prone position on a dedicated digital Fischer table.

RESULTS

Fifty-one, or 25%, of 200 clusters of microcalcifications corresponded to carcinomas: 126 benign lesions, 23 atypical hyperplasia and LCIS, 31 DCIS, 15 invasive ductal carcinomas, and 4 false negative biopsies. In these 4 last cases, surgery was performed because radiographs of the core biopsy showed no microcalcifications; carcinoma was confirmed at histology of the surgical specimen. Using the BI-RADS system, 7 lesions were category 3, 175 lesions were category 4, and 18 lesions were category 5. From a total of 52 masses, 31 were benign lesions, 2 were borderline lesions, and 19 were invasive carcinomas. From these, 5 lesions were category 3, 31 were category 4, and 16 were category 5. Diagnostic surgical biopsy was avoided in 161 cases (63%), in 152 cases for benign lesions including 151 lesions classified as category 4 lesions and in 9 cases for multifocal or recurrent malignant lesions.

CONCLUSION

When technical pitfalls are avoided and when presence of microcalcifications in the core biopsy sample is verified, vacuum assisted core biopsy with Mammotome((R)) 11G provides accurate diagnosis of non-palpable mammographic abnormalities.

First recovery of Schistosoma mansoni eggs from a latrine in Europe (15-16th centuries)

Schistosoma mansoni eggs were found in a latrine dated AD 1450-1550 in Montbéliard, France. This is the first record of intestinal schistosomiasis in archaeological material. Because the parasite has an African origin, its presence in Europe at that time may be due to African slaves. However, intestinal schistosomiasis has never been established in Europe.

Ancient DNA from Ascaris: extraction amplification and sequences from eggs collected in coprolites

On the Middle-Age site of Namur (Belgium) the analysis of coprolites revealed the presence of many well-preserved Ascaris eggs. Following rehydratation of the coprolite samples, 104 eggs were collected and extracted with an ultrasonication and phenol-chloroform based method. Three overlapping fragments of the 18S rRNA gene and one fragment of the cytochrome b gene have been reproducibly amplified, cloned and sequenced. The analysis of these sequences confirms the identification of the eggs as coming from Ascaris. Our study reveals that coprolites can be an interesting source of parasites that can be readily identified using molecular approaches. The study of ancient DNA from helminth parasites is of interest as it may answer long-standing questions in the history of infectious diseases and gives a possibility to compare these ancient sequences with those of modern populations.

Identification of parasitoses in a child burial from Adak Island (Central Aleutian Islands, Alaska)

Bothriocephalid (Diphyllobothrium pacificum) and Ascarid (Ascaris lumbricoides) eggs have been identified in a sample taken in the abdominal cavity of a child skeleton found in Zeto Point (ADK-011), an archaeological site on Adak Island in the Central Aleutian Islands (Alaska).

[Solenophagy and telmophagy: biting mechanisms among various hematophagous insects]

Blood-sucking insects do not all take blood from the host in the same way. Mechanisms are different according to capillary feeding or pool feeding and this explains the differences between clinical reactions. A better knowledge of the insect biology is helpful for an aetiological diagnosis. So, in the case of an allergic reaction, procedures of complementary investigations will be optimised.

[Allergy to the bites of blood-sucking insects: clinical manifestations]

Blood-sucking insects and other arthropods may occur allergic reactions when stinging. Usually, inflammatory symptoms are mild with a locoregional extension. Pruritus may be painful and sometimes patients experienced a functional impotency. Systemic reactions are possible. Anaphylaxis is rare and rather observed with ticks (Ixodes and Argas) and kissing-bugs. The circumstances and mechanisms of the sting related to the knowledge of the insect biology elicit the clinical symptoms. Skin prick-tests are usually not practicable. Indeed, the diagnosis remains based upon anamnestic and entomological data because the poor sensibility of in vitro tests. However, some immunological investigations gave signs of interest for prospective studies. Symptomatic drugs and prevention advices must be purchased for exposed patients.

First paleoparasitological analysis of a midden in the Aleutian Islands (Alaska): results and limits

Excavations on Buldir Island, Aleutian Islands, Alaska, have revealed the remains of several features dated between the 13th and 17th centuries A.D. Soil from an open-air workshop, represented by 2 excavated pits, and a structure built of whale bones were sampled for evidence of parasites and microfloristic remains. Two groups of helminth eggs (Diphyllobothrium and Ankylostomidae) were identified in samples from the open-air pits; microfloristical remains were found in all samples. This is the first paleoparasitological analysis conducted on an Aleutian midden.

Entropy maps characterize drug effects on brain dynamics in Alzheimer's disease

Non-linear quantifiers of brain electrical dynamics (entropy maps computed from the degradation of temporal forecasting of EEG signals) were studied in relation to drug treatment of Alzheimer's disease. A placebo condition was compared to three drug doses (50, 100 and 200 mg). A significant general effect of the drug was found when compared to placebo and specific contrasts between placebo and each of the three drug doses only reveal a significant entropy increase for the highest dose. These effects were localized bilaterally in fronto-temporal areas and support changes in the dynamics of the cerebral structures involved in memory processes.

[Helminth eggs: trace elements of neolithic and paleolithic parasitosis on French sites]

On the neolithic site of Chalain (Jura, France), the analysis of human coprolites has revealed the presence of many well preserved eggs of Helminths: eggs of Trichuris spP., Capillaria spp., Fasciola hepatica, Diphyllobothrium spP. In the paleolithic picturial sanctuary of the Grande Grotte at Arcy-sur-Cure (Yonne, France), eggs of Ascaris spP. have been discovered. The presence of these parasits open a new way of search about the knowledge of ancient populations.

Recovery of helminth eggs from archeological excavations of the Grand Louvre (Paris, France)

Archeological excavations at the Grand Louvre in Paris, France, during 1985-1990, provided an opportunity for paleoparasitological investigation at various ancient sites of habitation, dating from the 11th to the 16th centuries. Eggs of helminths were recovered by means of sedimentation and flotation. The genera of helminths represented were Ascaris, Trichuris, Heterakis, Metastrongylus, Fasciola, and Dicrocoelium.

[Paleoparasitology: presumption of a case with bilharzia of the 15th century at Montbéliard (Doubs, France)]

On the archeological site of Montbéliard, paleoparasitological and sedimentological analysis of cesspit deposits led to the detection of well preserved parasitological forms (remains of helminths with associated eggs). The morphology and morphometry of these forms point to a plausible case of bilharzia transmitted by Schistosoma haematobium. The chance of ancient or recent contamination of the sample is discussed.

[First paleoparasitologic approach of the neolithic site in Chalain (Jura, France)]

On the neolithic site of Chalain, the analysis of 12 human coprolites and of 10 sediment samples rich in organic matters has revealed the presence of many well preserved eggs of Helminths: eggs of Trichuris/Capillaria, Fasciola hepatica and Diphyllobothrium sp. The interest of palaeoparasitological analysis in Archaeology and the impact of taphonomical process on the parasitological material are discussed.

[Pattern of blood creatinine levels in 140 hypertensive patients after successful percutaneous transluminal angioplasty for renal artery stenosis]

Long term effects on creatinine serum level of successful percutaneous transluminal renal angioplasty were retrospectively studied in 140 patients. 3 groups were distinguished: the first one (80 patients) included unilateral renal angioplasties, with normal contralateral kidney and renal artery; the second group (35 patients) included bilateral renal angioplasties; the third group (25 patients) included solitary kidney renal artery angioplasties. In each group, subgroups were defined whether creatinine serum level was upper or lower than 130 mumol/l. Renal function was considered to be improved if serum creatinine was reduced by 20% or more, maintained if serum creatinine variations were below 20%, worsened if its increase was upper than 20%. Global complication rate was 4.9% (9 between 185 patients) of whom 1 (0.54%) needed a surgical revascularization. At the end of follow-up (mean between 4 and 10 months), subgroups improvement and stabilization rates varied between 67 and 100%, with the best scores in the second group (96.2 and 100%) and solitary kidney with renal insufficiency subgroup (77.25%).

Laboratory rearing of Phlebotomus perniciosus (Diptera: Psychodidae) and fungal growth problems

One of the difficulties of growing sandflies in the laboratory is fungal contamination. This study of the laboratory rearing of Phlebotomus perniciosus reports on the nature and circumstances of fungal contamination. Fungal growth is favoured during winter and diapause. The harmful effects vary with the fungal species and the larval stages. The solution to the problem lies on the use of aseptic techniques and the avoidance of overfeeding.

Ultrastructural changes following treatment with a microwave pulse in the oocyst of Eimeria magna Perard, 1925

The ultrastructure of oocysts of Eimeria magna was studied before and after their exposure to unique pulse of microwaves (2.450 MHZ; 600 W) of different durations (10, 15 and 20 s). Following treatment, the progressive destruction of the three layers of the oocyst wall was observed, the innermost being destroyed first. Internal structures were also affected, resulting in swollen mitochondria, a loss of ribosomes and fragmentation of the rough endoplasmic reticulum; moreover, the wall-forming bodies were no longer identifiable. Further studies using microwave pulses on biological material should be carried out to improve our understanding of the consequences of such treatment and to investigate its utility in the control of transmissible pathogenic organisms.

Ultrastructural studies of alterations induced by microwaves in Toxocara canis eggs: prophylactic interest

The ultrastructure of Toxocara canis eggs is described before and after exposure to microwaves. The morphology of normal eggs is compared to that of eggs from other helminths. Following treatment, the complete disorganization of the surface structure of the shell and the loss of much turgidity of the egg are observed. The destruction of the internal structure is most marked in the center of the egg and is associated with the disappearance of some layers of the shell. In addition, there is substantial damage to the synthesis apparatus (ribosomes, endoplasmic reticulum, lipid cisternae). An explanation based on the specific action of microwaves and micro-overheating is proposed, and the prophylactic use of this technique is considered.

[Venous Doppler ultrasonography. Methods, indications and limits]

The analysis of velocities by the Doppler effect has limited applications in venous pathology. There are, however, many potential advantages: the introduction of deep venous catheters, early diagnosis of venous thrombosis, studies of venous incompetence, right sided cardiopathies, follow-up of medical and surgical treatment (thrombolytics, venous thrombectomy, bypass surgery, vena cava clips). The results in a series of venous thrombosis are reported: the correlation between Doppler and phlebography was 86,5% in 110 investigations. Doppler sensitivity was 86% and specificity 91%. These results are compared to other reports. A 90% correlation was found with isotope venography in 32 cases in which the permeability of vena cava clips was studied. The sensitivity of doppler in the diagnosis of thrombosis of the clip was 75% and its specificity 100%. The main limitations were the lack of sensitivity in the diagnosis of distal thrombosis and incomplete occlusion (floating thrombi). As a complement to occlusive plethysmography and other non-invasive investigations, Doppler ultrasonography helps determine the indications for phlebography. It is useful in detecting high risk patients and is a sensitive, effective non-invasive method of surveillance in the postoperative period.

[Exploration of major veins by Doppler ultrasonography. Indications and limits (author's transl)]

Doppler ultrasonography is a first-choice, non-invasive, inexpensive and repeatable procedure for exploring major veins and for detecting venous thrombosis, venous insufficiency and arterio-venous fistulae. It also provides invaluable information on post-operative haemodynamics in cases of thrombectomy, venous shunt and vena cava clip, and helps in evaluating the effectiveness of thrombolytic agents. Its sensitivity is satisfactory: in 110 patients with suspected phlebitis, there was an 86,5% agreement between the results of doppler ultrasonography and those of phlebography. False negative results are encountered with distal thromboses and, unfortunately, floating clots (there were 3 cases of undetected iliac vein floating clots in this series). It seems rational to use Doppler ultrasonography in patients with high risk venous diseases. The method will not replace phlebography, but when applied on correct indications, it may substantially reduce the number of negative or unassessable results.