Comparaison de deux méthodes de mesure des TLG en TEP au 18-FDG dans le mélanome métastatique

IntroductionThere are many automated segmentation softwares in PET-CT, but none of them is used as gold standard. The aim of this study is to compare two segmentation softwares, one based on maximum intensity projection (MIP-based) and the second: PETVCAR^®, to measure TLG in patients with metastatic melanoma treated by vemurafenib.Materials and methodsSixteen patients were assessed by PET using 18-fluorodesoxyglucose (18-FDG) before and during the treatment with vemurafenib. TLG were measured by MIP-based and PETVCAR^® and then analysed in initial PET, all PET, by organ and added for each PET.ResultsThere is a good correlation between TLG in each method (r = 0.96 with P = 0 on 439 lesions on all PET). The mean difference between TLG PETVCAR^® and TLG MIP-based is negative. Segmentations are larger with MIP-based than with PETVCAR^® with discrepancies observed for larger and heterogeneous lesions. SUV_max doesn’t seem to be the factor causing these discrepancies. Correlation between the difference of TLG and their mean is also strong especially in bones, nodes and subcutaneous lesions.ConclusionBoth methods have a good correlation in spite of discrepancies observed for large or heterogeneous lesions. These lesions segmentations are larger with the method based on MIP than with PETVCAR^®.     

Changements de l'epithélium médian des bourgeons palatins de souris au stade de préfusion

Résumé Avant d'entrer en contact, les surfaces de fusion des processus palatins subissent des modifications. Certaines cellules épithéliales superficielles deviennent turgescentes, alors que d'autres conservent un aspect dense et aplati, elles se lysent et éclatent. Des noyaux semblables à ceux des assises profondes se retrouvent en surface, paraissant migrer vers le bourgeon antagoniste. Des projections filamenteuses apparaissent, quelques unes établissant un contact avec l'épithélium opposé, d'autres restant seulement sous forme d'expansion. Ces observations sont concordantes en microscopie photonique et en microscopie électronique à balayage.

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Modification of the medial epithelium of the palatal shelves of mice at the prefusion stage. A light and scanning electron microscopy study

Summary The fusion surfaces of the palatal processes are modified before coming into contact. Several superficial epithelial cells become hypertrophied, undergo lysis and burst, whereas others remain flattened and densely stained. Nuclei, similar to those localized in deeper layers are found on the surface and seem to migrate towards the opposite process. Filamentous projections appear and some establish a linkage with the opposite epithelium, whereas others expand freely from the surface. Light microscope observations agree with scanning electron microscopy findings.

     

Étude dosimétrique de préparations de médicaments radiopharmaceutiques au 68Ga

AimProduction of ⁶⁸Ga-radiopharmaceuticals is a rapidly growing field in France. However, operators may already be involved in other radiopharmaceutical activities. It is thus necessary to know the exposure of this new activity.Material and methodsFor passive dosimetry, a radiophotoluminescent (RPL) dosimeter, a thermoluminescent (TLD) chip, 2 TLD rings and a passive dosimeter for crystalline were used. For active dosimetry, an extremity dosimeter and a whole body dosimeter were used. This study was performed during semi-automatized production of ⁶⁸Ga-investigational medicinal products. Values were normalized to 500MBq manipulated (median activity using a 1850MBq ⁶⁸Ga-generator), 60 radiosynthesis (maximum enrollment ability of our center) and 2 operators. A LB123 proportional counter was used for quantification of external exposition to 10MBq ⁶⁸Ge and internal exposition by inhalation was theoretically assessed. ⁶⁸Ga emission attenuation by collective protection equipments was also discussed.ResultsConsidering passive dosimetry, the equivalent dose to extremities was 21.75 ± 0.34 mSv, the whole-body effective dose was 0.189 ± 0.011 mSv and the dose to crystalline was 0.925 ± 0.009 mSv. Considering active dosimetry, the equivalent dose to extremities was 8,75 ± 0.12 mSv and the whole-body effective dose was 0,088 ± 0.009 mSv. Total exposure to ⁶⁸Ge was 1.75 μSv.ConclusionIn our hands, ⁶⁸Ga is a directly transposable activity in radiopharmacies already equipped for ¹⁸F because of a dosimetry complying with regulatory limits and suitable radiation protection of collective equipments.     

Comparaison de différents indices métaboliques et de la méthode SULTAN dans l’évaluation de la réponse thérapeutique par TEP au 18FDG dans le cancer du sein métastatique

Objective18F-FDG PET is a valuable tool in the evaluation of therapeutic response in breast cancer. This retrospective study was designed to compare the performance of six metabolic indices and to define their optimal thresholds, in patients treated with chemotherapy or hormone therapy for metastatic breast cancer. The performances of a parametric analysis by SULTAN method were also evaluated.MethodsTwenty patients, who underwent from 2 to 7 PET during the follow-up were analyzed. For each target, six indices were measured: SUVmax (maximum Standardized Uptake Value), SUVpeak, SAM (Standardized Added Metabolic activity), metabolic volume (MV), SUVmean using an adaptive threshold, and TLG (total lesion glycolysis). The percentage change of each target between each PET was calculated. A method based on parametric imaging (SULTAN) was also applied to each patient. The results were compared to the gold standard, defined by clinical evaluation, biological and morphological imaging RECIST 1.1 criteria. A per-lesion and per-patient analysis were performed and the optimal thresholds for each indices were calculated.ResultsFor the per-lesion analysis, 61 targets and 111 evolutions with 67 responders (R) and 44 non-responders (NR) were studied. Using ROC curve analysis and intercomparison, SUVmax, SUVpeak and SUVmean were significantly better than SAM, TLG and VM (P < 0.05). Using the optimal thresholds of −21%, –21%, –34%, –48% and –23% for SUVmax, SUVpeak, SUVmean, SAM and TLG respectively, these five indices were significantly correlated with the gold standard. SUVmax, SUVpeak and SUVmean showed the best performances of sensitivity (88%, 87% and 78% respectively), specificity (93%, 93% and 98% respectively) and negative predictive value (NPV) (84%, 69% and 74% respectively). For the per-patient analysis, 42 pairs of PET with 22 R and 20 NR were studied. Only SUVmax and SUVpeak were correlated to gold standard with the 30%-PERCIST-threshold and with optimal thresholds with performances of sensitivity of 73% and 77%, specificity of 95% and NPV of 76% and 79%. Parametric analysis with SULTAN showed excellent performances in the per-lesion and per-patient analysis (sensitivity 84% and 82%, specificity 98% and 90%, NPV 80% and 82%, respectively).ConclusionSUVmax and SUVpeak appeared the best indices to evaluate metabolic response in metastatic breast cancer. The SULTAN method was a reliable method to assist interpretation.     

Quelques considérations sur l'enseignement de la médecine physique et de la réhabilitation

Particularly since World War II physical medicine and rehabilitation have assumed a growing importance. The efforts of the Canadian Association of Physical Medicine and Rehabilitation, following a survey of Canadian universities, to increase the theoretical and practical teaching of physiatrics are emphasized. It is considered important that the teaching of physical medicine and rehabilitation should be carried out concurrently with other medical and surgical teaching programs. Paramedical and auxiliary rehabilitation personnel should participate in the teaching program. The number of hours devoted to physiatrics should be increased, and the medical student should be permitted to choose physical medicine and rehabilitation as a part of his internship program.     

Structure fine de l'eminence médiane de souris au cours de son ontogenese

Résumé Les fibres nerveuses renfermant des vésicules granuleuses et des vésicules de type synaptique apparaissent dans l'éminence médiane de foetus de 14 jours. Dés le 18è jour foetal, de véritables terminaisons nerveuses sont au contact des capillaires du plexus intercalaire, constituant une charnière neurohémale. Les anses intrainfundibulaires commencent à pénétrer dans l'éminence médiane à la naissance mais ce n'est que chez des souris de 5 jours qu'elles deviennent très nombreuses. — Nous discuterons sur des critères morphologiques, de la possibilité d'un contrôle hypothalamique sur l'adénohypophyse avant la naissance.

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Fine structure of the mouse median eminence during early stages of its ontogenesis

Summary Nerve fibers containing granular vesicles and vesicles closely resembling synaptic vesicles appear in the median eminence of 14 days old mouse fetuses. At 18th fetal day true nerve endings have been observed which are located close to the capillaries of the superficial plexus forming a neurovascular link. The capillary loops penetrate into the median eminence at the time of parturition but only in 5 days old mice they can be observed more frequently. — On the basis of the morphological observations presented the question is discussed whether the hypothalamus can influence pituitary hormone secretion before birth.

     

Une nouvelle méthode de marquage pour certains groupes d'Insectes et de Crustacés

A new technique of labelling, based on making series of microscars on the compound eye of immature insects, allows to recognize individual specimens, even after several moults.

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Une nouvelle méthode de marquage pour certains groupes d'Insectes et de Crustacés

     

Principes de la lecture critique de la littérature médicale: Illustration urologique

There has been an enormous expansion in scientific literature, especially in the area of health and medicine. At the same time the complexity of the research has increased. Through the reading of medical literature of his field of interest, the physician is in search of useful information. However, reading medical papers is very time consuming and most physicians, for their usual literature review, content themselves with the titles and the abstracts. Moreover, quality and relevancy of the publications vary greatly and the reader must be able to “separate the wheat from the chaff”. Thus the reading of literature needs selection and evaluation. As a result, physicians require critical appraisal skills. The principle of appraisal of medical literature is to assess the value of publications which will influence the medical practice of the reader. The reader has a double objective: to assess the credibility of the publications, and to define the applicability of the publication information. By following eight steps the reader is able to quickly rule out from his reading what is not valid and have an objective look at the quality of the results which are proposed to him. These eight steps comprise the assessment of the study objectives, the study design, the study factor(s), the outcome factor(s), the study population and sample, the confounding factor(s) and bias, the results with their statistical and clinical significance and the power of the study, and, lastly, the synthesis of the reader's judgment. The last word belongs to the clinician facing his patient.     

Etude de la migration des cellules somitiques dans le mésoderme somatopleural de l'ébauche de l'aile

Summary In chick embryos, observations were made on serial semithin transverse sections of the wing level. In addition homo- or heterotopic replacements of the wing or leg somitic mesoderm by labelled somitic or nonsomitic mesoderm were made in 2-to 2.5-day embryos. The nuclear label used was either natural (quail donor embryos in heterotopic transplantations) or isotopic (chick donors labelled with tritiated thymidine).Histological examination revealed that the first somitic cells to leave somite 15 apparently did so at the 20 to 22 somite stage, while the last ones to leave somite 20 apparently did so shortly before the 36 somite stage.Transplantation experiments with labelled donor cells revealed the routes of migratory somitic cells and the time-course of their invasion into the outgrowing limb bud (non-somitic graft cells did not noticeably invade the limb anlage). They showed furthermore that the somitic mesoderm is not regionalized with respect to its limb myogenic properties.These results are compared with those obtained in other classes of vertebrates.

Ce travail a été subventionné en partie par la D.G.R.S.T. et le C.N.R.S.