Modélisation de l'impact des mollusques cultivés sur la biomasse phytoplanctonique de l'étang de Thau (France)

A model coupling a 2D transport equation and a simple model of the nitrogen cycling was developed for the Thau lagoon (France). The model took into account the wind forcing on the hydrodynamism, the effect of the temperature on the biological processes, the input of the watershed area, the light dependence of the pelagic primary production and the prédation of the phytoplankton by the cultivated filter feeders. The model ran under two steady-state situations of wind with constant temperature and light values corresponding to spring weather conditions. Simulations showed that the biological flows were very sensitive to the wind. The budget of the nitrogen flows were computed for the three areas devoted to the filter feeder cultivation and the results highlighted the impact of cultivated oysters as a source of nutrients and an important nitrogen flow through the predation of phytoplankton.     

Impact de la méthode de segmentation dans la caractérisation des adénocarcinomes pulmonaires en TEP-TDM au 18FDG

ObjectiveThe treatment of lung adenocarcinomas is conditioned by the presence of certain genetic abnormalities. Certain quantitative parameters obtained from FDG PET-CT, at the voxel scale, provide tumour shape and texture characteristics and might predict their mutational status. Our objective was to determine the impact of the segmentation method in the characterization of lung adenocarcinomas in FDG PET-CT.MethodsForty-nine patients with pulmonary adenocarcinomas were retrospectively included, with their initial FDG PET-CT image. The studied tumours were big, heterogeneous and difficult to segment automatically. The automatic FLAB algorithm was used with and without manual adjustment. The parameters were extracted and compared to the ALK, PDL1, and KRAS status, in order to compare the performances of the two segmentation methods. Their performance was determined by the ROC curve method.ResultsSeveral parameters were significant to predict genetic status (AUC > 0.65). The best performing parameters were different according to the genes studied and according to the resampling methods used. The results were less dependent on resampling in automatic segmentation without manual adjustment. The best performing parameters were volume dependent parameters for segmentation with manual adjustment, and texture parameters for automatic segmentation without adjustment.ConclusionThe study of texture parameters is more efficient in automatic segmentation that is not manually adjusted, and it is advantageous to use a manual adjustment when studying volume-dependent parameters in the case of very heterogeneous tumors.     

Influence de la durée de l'éclairement sur la croissance du thalle de quelques algues (trois chaetophorales et une rhodophycee)

Thallus growth of some algae as a function of the light period (fluorescent white light about 1000 lux) shows that continuous light, or better 18 h of light, are the most effective; however short (1 or 2 h) and long dark periods inhibit growth. Except for Caespitella pascheri, monochromatic irradiations of 6 or 12 h (in addition to the 18 or 12 h of white light) inhibit the growth of algae. On the contrary, after 23 h of white light, monochromatic radiations stimulate growth and the more effective wavelengths are: 443, 475, 575 and 675 nm. With incandescent light (rich in near far-red and poor in blue light), the growth is low.     

Impact de la pollution sur les communautés zooplanctoniques dans la zone d'épandage de l'émissaire urbain de Marseille

Résumé Des prélèvements effectués le long du trajet d'une bouée larguée à proximité de l'émissaire de Marseille-Cortiou, ont permis d'étudier la distribution des populations zooplanctoniques en liaison avec la zonation des caractéristiques physico-chimiques de l'aire prospectée. Dans cette aire, on peut reconnaitre trois zones: — Une zone très polluée de 2 kms de largeur environ où ne sont abondantes que quelques espèces (Acartia clausi Giesbrecht, Oithona helgolandica Claus, Oïkopleura sp.); — une zone intermédiaire juxtaposée à la précédente dans laquelle on trouve, outre les espèces tolérantes précitées, des espèces qui le sont moins (Paracalanus parvus Claus, Clausocalanus sp., Centropages typicus Kröyer, Fritillaria sp.) dont le nombre augmente régulièrement dans la 3ème zone, la moins polluée. S'il n'existe pas d'espèces indicatrices d'eaux polluées, on remarque des associations d'espèces plus résistantes que les autres dans les milieux eutrophes et pollués.

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Zooplankton populations have been studied in a polluted area situated near the domestic sewage discharge of Marseilles.Samples were collected along a transect following the course of a float casted off close to the outlet. From this outlet, three zones, corresponding to decreasing pollution, appear in zooplankton populations: 1 — the most polluted one where few tolerant species are abundant (Acartia clausi, Oithona helgolandica, Oikopleura sp.); 2 — an intermediate one, where the densities of some less tolerant species increase (Paracalanus parvus, Clausocalanus sp., Centropages typicus, Oncaeidae and Corycaeidae); 3 — a third zone, where typically neritic populations are present, but can be subject to partial pollution because of residual polluted patches of water.

     

Influence de la méthode de fixation sur l'observation des divisions cellulaires dans l'adénohypophyse du rat mâle

Résumé Les mitoses de l'adénohypophyse du rat mâle ont été examinées comparativement après fixation par perfusion et après fixation par immersion.Après fixation par perfusion la répartition topographique des mitoses dans le parenchyme est homogène, et l'index mitotique est de 1,85 pour 1 000 cellules.Après fixation par immersion, la densité des mitoses décroit de la périphérie vers le centre, et l'index mitotique n'est que de 0,80 mitoses pour 1 000 cellules.La lenteur de pénétration du fixateur pendant l'immersion est tenue pour principal responsable des différences observées. Elle entraîne une modification de l'aspect des mitoses, telle que plus de la moitié d'entre elles ne sont pas identifiables et échappent aux comptages.

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Influence of fixation on the observation of mitoses in the male rat adenohypophysis

Summary The mitoses of the adenohypophysis in male rats have been observed comparatively after fixation by perfusion and fixation by immersion.After fixation by perfusion, the topographic distribution of mitoses throughout the parenchyma is homogenous and the mitotic index is 1.85 for 1 000 cells.After fixation by immersion, the density of the mitoses is decreasing from the periphery towards the center and the mitotic index is only 0.80 for 1 000 cells.The slow penetration of the fixative during fixation by immersion is considered to be the main cause in the differences observed. This slow action causes a modification in the aspect of the mitoses, and more than fifty percent of them cannot be identified and escape to the counts.

Avec la collaboration technique de Mademoiselle J. Rameau.     

Étude sur la végétation des hautes altitudes de l'île de la Réunion (Océan Indien)

Summary The high mountains of Reunion Island (Indian ocean) harbor an ericaceous vegetation dominated byPhilippia montana. After a brief survey of the chief ecological factors, the author describes the main plant communities. Their physiognomy, floristic structure and succession have a close relation with edaphic factors.

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Zusammenfassung Das Gipfelgebiet der beiden vulkanischen Bergst?cke der Insel Reunion (Indischer Ozean) tr?gt eine Erikazeenvegetation, in welcherPhilippia montana als vorwiegende Art erscheint. Nach einer kurzen Untersuchung der bedeutendsten ?kologischen Faktoren definiert der Autor die Pflanzengesellschaften deren Physiognomie, Blütenstruktur und Entwicklung mit den edaphischen Faktoren eng zusammenh?ngen.

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Pour le nomenclature de la plupart des espèces, voir les tableaux 3 et 4.     

Influence des conditions préalables de culture sur le métabolisme de l'éthanol et de l'acide acétique par la levure

Résumé Le milieu de croissance préalable semble intervenir sur l'aptitude des levures à métaboliser l'éthanol et l'acide acétique. Dans certains cas, les deux substrats activent l'oxydation des réserves. Ce phénomène se produit avec des levures cultivées sur milieu synthétique contenant du glucose 2% ou de l'éthanol 1%. Il ne se produit pas avec des levures cultivées sur ce même milieu synthétique contenant du glucose 0,5%. Il ne peut cependant être expliqué, ni par une richesse supérieure des cellules en réserves glucidiques, ni par un déséquilibre alimentaire, ni par une différence d'activité respiratoire.

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Influence of culture conditions on ethanol and acetic acid metabolism of yeast

Summary The medium in which yeasts are grown seems to modify their ability to metabolize ethanol and acetic acid. In certain cases, the two substrates activate the oxidation of reserves. The phenomenon is observed with yeasts grown on synthetic medium with glucose 2% or ethanol 1%. It is never observed with yeasts grown on the same medium with glucose 0.5%. It cannot be explained either by an elevated cellular level of carbohydrate reserves, by a nutritional imbalance, or by a difference in respiratory activity.

     

Etude du métabolisme des acides nucléiques et des protéines au cours de l'initiation de racines adventives

Summary Changes in the metabolism of nucleic acids and proteins were followed during the initiation of adventitious roots of Cicer arietinum. During the first 24 h, several phases of activation of the metabolism were found. The use of inhibitors of RNA synthesis showed that an early phase of incorporation of precursors into RNA is essential for the initiation phenomena. This phase is more sensitive to inhibitors and activators (hormones) than all other phases. The rapid turn-over of RNA synthesized during the first 6 h and the inefficience of inhibitors after this time suggested that a stable (non-RNA) factor maintains the activation. This factor must be synthesized soon after the stimulus of cutting.     

Interêts du dosage des adénosines 5′-phosphate pour l'étude de la dynamique des populations phytoplanctoniques lacustres (le Pavin - France)

A study on A.T.P., A.D.P. and A.M.P. in the phytoplankton of Lake Pavin was carried out from November 1976 to December 1977. Samples were collected at nine depths, between the surface and 50 m.A.T.P., A.D.P. and ( = A.T.P.+ A.D.P. + A.M.P.) show a similar behaviour in space and time but A.M.P. behaves independently. The A.M.P. concentration is high only when primary production of phytoplankton is high.The energy charge [CE = (ATP + % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSGaaeaaca% aIXaaabaGaaGOmaaaaaaa!3776!\[{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$2$}}\]ADP)/(ATP + ADP + AMP)] could be used as measure of adaptation in algal populations. Indeed, the energy charge increases as algal cells experience difficulty in maintaining themselves in the biotope.

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Interêts du dosage des adénosines 5-phosphate pour l'étude de la dynamique des populations phytoplanctoniques lacustres (le Pavin - France)

     

Nouvelles recherches sur la systématique et l'éthologie des Termites champignonnistes du genreBellicositermes Emerson

Sans résumé     

Impact diagnostique de l’imagerie hybride TEMP/TDM dans la prise en charge des neuroblastomes. Expérience du service de médecine nucléaire du CHU Mohammed VI de Marrakech

IntroductionThe neuroblastoma is a malignant pediatric tumor of the peripheral sympathetic nervous system. This is the pediatric solid extracranial tumor most common and accounts for approximately 8 to 10% of childhood cancers. The diagnosis is based on imaging showing a tumor developed at the expense of the sympathetic nervous system, increased urinary catecholamines, increased uptake of meta-iodo-benzylguanidine (MIBG) and histology who finds a malignant proliferation of small round cells. An assessment of the tumor mass and its extension are required to assess the prognosis and adapt the treatment. The MIBG scintigraphy is a non-invasive imaging technique that can evaluate with a single review the totality of the tumor extension. The single-photon emission computed tomography/computed tomography (SPECT/CT) improves the sensitivity of the examination, it allows an anatomical and functional study and improves the anatomical localization of scintigraphic uptake observed. The purpose of our work is to illustrate the contribution of the SPECT/CT in addition to the planar MIBG scintigraphy in the diagnosis and staging of neuroblastoma about four cases.Case reportClinical case 1: a 4-year old child, presented for 2 months abdominal pain. In the clinical examination, he presented a hard abdominal mass, painless and right paramedian. Abdominal ultrasound showed a right retroperitoneal mass with lymph nodes. The dosage of urinary catecholamines was increased. The ¹³¹I-MIBG scintigraphy showed an image for a right adrenal neuroblastoma measuring 8.6 × 4.5 cm. Surgical excision of the adrenal mass revealed in the anatomopathologic study a malignant tumoral proliferation with round cells compatible with a neuroblastoma. Clinical case 2: a 10-month old infant, presented since 15 days an exophtalmia with poor general status. The clinical examination showed a right abdominal mass and a bilateral periorbital ecchymosis. The radiography of the thorax showed a widening mediastinal. Abdominal echography showed a tissular mass of the right adrenal gland with retroperitoneal lymph nodes and an ascites. The dosage of urinary catecholamines was increased. The ¹³¹I-MIBG scintigraphy showed a right adrenal neuroblastoma measuring 6.4 × 2.7 cm with orbital bone metastases in favor of a Hutchinson syndrome. Clinical case 3: a 2-month old infant, followed since 1 month for bilateral adrenal neuroblastoma. The clinical examination showed an important abdominal distension with bluish nodules under skin. The abdominal echography and the abdomino-pelvic TDM showed two adrenal masses corresponding to a bilateral neuroblastoma with liver metastases. The ¹³¹I-MIBG scintigraphy showed two adrenal masses measuring respectively 6.5 × 3.4 cm and 8 × 6 cm, with liver and skin metastases in favor of 4S neuroblastoma with bilateral adrenal tumors. Clinical case 4: a 3-year old child, followed for left adrenal neuroblastoma with multiple bone metastases. The clinical examination showed a left abdominal mass with exophtalmia and right palpebral ecchymosis. The radiography of the thorax showed a widening of the mediastin with repression of the paravertebral right line. Abdominal echography showed a left retroperitoneal tissular mass measuring 9.2 × 5.2 cm. The abdomino-pelvic TDM showed a left adrenal tumor with lumbar vertebral bone metastases. A first ¹³¹I-MIBG scan showed a left neuroblastoma with multiple bone metastases in the right orbit, the right humerus, the occipital bone, the right scapula and spine (D10, D11, L1, L3, S1). The child was treated by 5 courses of chemotherapy (protocol HRNLB/10). The ¹³¹I-MIBG scan control showed a regression of neuroblastoma size (1.4 × 1.2 cm) with loss of bone metastases of the occipital bone, the right scapula and spine.DiscussionThe MIBG scintigraphy is a simple, non-invasive examination that has excellent sensitivity and specificity in detection of neuroblastoma and especially in invasion bone marrow and in evaluation of the therapeutic response. The hybrid SPECT/CT imaging improve the performance of the scintigraphy as well in sensibility, toward the deep localization, as in specificity for images poorly defined in planar imaging.