Les vertébrés du Berriasiende Canjuers (Var,France) et leur environnement

The vertebrate fossil locality of Canjuers correspondsto a protected marine environment near an emersive zone, on the shelf of Middle Verdon, in communication with the open sea (toward the North) through channels. The fishes (carnivorous pelagic and planctonivorous pelagic) are the most abundant vertebrates. They were already dead when they reached the depositional area, together with the floated shells of ammonites. The necton, dependent on the bottom for its food and the fixed benthos are nearly absent. The free and sessile benthos, poor in species, shows adaptations to a muddy bottom and rare forms adapted to a hardened bottom. The microfauna is rare. The infauna (essentially horizontal) is present inside the channels. The water temperature, the very low hydrodynamism and the lack of infauna imply difficult conditions on the bottom (micrite beds and laminites in the lower part of the deposit). Tridactyle tracks of vertebrates confirm, on the other hand, the feeble depth of the water. The near supratidal zone was more or less colonised by vegetation and was occupied by a very differentiated reptilian fauna (flying forms, continental running and burrowing forms, swimming forms) corresponding to a continental environment. The biotic and abiotic factors show the occurence of four distinct environments: protected low depth marine, channels, supratidalintertidal and pure marine. The taphonomy corroborates that the deposit was a thanatocoenosis for the marine organisms, except when water movement permitted life.     

Scintigraphie cérébrale de perfusion et troubles cognitifs d’origine vasculaire

The vascular cognitive impairment (VCI) is a heterogeneous group of various etiologies, which share a presumed vascular cause. Although the age is the most important risk factor, the cardiovascular risk factors are also involved. A relatively high proportion of these cognitive disorders could be prevented or delayed. Only the treatment of arterial hypertension is recognized as a factor in preventing vascular dementia. MRI is the examination of choice for the investigation of cerebral vascular pathology. However, this morphological imaging is insufficient and does not provide useful functional information. Perfusion brain SPECT is not widely used in the exploration of VCI. Strategies for screening VCI are not standardized and long-term studies are needed to establish the better prevention of cognitive vascular disorders. This article aims to summarize the possible benefit of cerebral perfusion SPECT in the exploration of VCI.     

Évaluation de la fonction ventriculaire gauche par l’utilisation d’une caméra à semi-conducteur Cadmium Zinc Telluride (CZT) : impact de l’échantillonnage temporel (8 vs 16 intervalles)

BackgroundNew CZT cameras provide an increased spatial resolution and sensitivity. The tomographic acquisition “in list mode” allows the evaluation of the left ventricular function using 8–16 intervals per cycle with an increased spatial resolution. However, the impact of temporal sampling on evaluation of the contractile function remains uncertain.Method^99mTc-sestamibi SPECT studies were acquired in 99 consecutive patients (70 men, 29 women) using an ultrafast CZT Camera (D-Spectrum, Spectrum Dynamics) and processed using both 8- and 16-interval (int). All patients underwent a stress (2 MBq/kg)-rest (6 MBq/kg) single day (stop condition: 700 KCTS within a myocardial VOI). Left ventricular function was assessed using QGS^®. Perfusion was analyzed using QPS^® and quantified using Summed Stress Score (SSS), Summed Rest Score (SRS) and Summed Difference Score (SDS) (17 segments model) and the extent of perfusion defects (% of LV).ResultsEight intervals gating overestimated the end-systolic volumes (ESV) and underestimated the left ventricular ejection fraction (LVEF) compared to 16 intervals (respectively for eight and 16 intervals: at rest [VTS: 45 ± 25 mL vs 41 ± 24 mL, P < 0.0001, LVEF: 53 ± 10% vs 59 ± 10%, P < 0.0001], and post-stress [VTS: 43 ± 24. mL vs 39 ± 24 mL, P < 0.0001; LVEF: 58 ± 10% vs 61 ± 11%, P < 0.0001]). However, it was not found significant differences between end diastolic volumes (EDV) (at rest: EDV: 98 ± 33 mL vs 97 ± 33 mL, P = NS; and post-stress: EDV: 98 ± 33 ml vs 99 ± 34 mL, P = NS). Parameters of left ventricular function were consistent between eight and 16 intervals (EDV: CCC = 0.99, ESV: CCC = 0.98, LVEF: CCC = 0.92, P < 0.0001). Correlation could not be evidenced between the extent of perfusion defect and the difference between eight and 16 intervals for the different parameters of left ventricular function both at rest and post-stress.ConclusionIn our study, comparison between eight and 16 intervals showed an overestimation of the ESV and an underestimation of LVEF, without correlation with perfusion abnormalities. The estimation of LVEF on CZT camera should take into account the chosen temporal sampling.     

Distribution physiologique cérébrale et corps entier du 18F-DPA-714 en TEP/TDM

ObjectiveTo investigate the physiological biodistribution of N,N-diethyl-2-(2 – (4 – (2-fluoroethoxy) phenyl) -5,7-dimethylpyrazolo [1,5] pyrimidin-3-yl) acetamide labeled with fluorine 18 (¹⁸F-DPA-714) in humans, by PET/CT in the brain and the whole body. The DPA-714 is a ligand of the translocator protein (Translocator Protein kDa or TSPO), protein overexpressed by microglia in case of neuroinflammation.Materials and methodsDynamic PET/CT brain acquisitions were performed in six healthy volunteers for 90 minutes after intravenous injection of ¹⁸F-DPA-714. Brain biodistribution of ¹⁸F-DPA-714 was assessed visually and using regions of interest (ROI), according to MNI AAL guidelines in order to obtain the activity/time curves for each brain region predefined. One of the subjects was also included whole body PET/CT acquisitions 1 hour after injection of ¹⁸F-DPA-714, allowing visual analysis and semi-quantitative distribution of the tracer, by definition of ROI and SUVs max computation.ResultsThe maximum brain uptake of ¹⁸F-DPA-714 was visualized at 3.5 minutes after injection, gray matter, mostly thalamic. This peak was followed by two elimination phases: an initial rapid phase (3.5 to 35 minutes) and a slower phase until the end of recording. Uptake of ¹⁸F-DPA-714 was generally consistent across brain structures analyzed. The whole body images show significant activity in the gallbladder, spine and salivary glands under the jaw, in accordance with previous published studies using other radioligands for TSPO.ConclusionThis very preliminary study confirms that the brain biodistribution of ¹⁸F-DPA-714 makes it an interesting marker of neuroinflammation. This work allows to recommend a PET protocol acquisition. However, it now seems necessary to implement these findings in patients referred for brain conditions.     

La séquence mésolithique et néolithique du Trou Al’Wesse (Belgique) : résultats pluridisciplinaires

The site of Trou Al’Wesse has been interpreted as a site of possible contact between Mesolithic and Neolithic populations, given the discovery of Neolithic ceramics and Mesolithic tools in stratum 4. However, recent excavations have also revealed the presence of three Early Mesolithic facies overlain by a Neolithic layer, while a Late Mesolithic presence is suggested for a fourth facies at the base of the terrace slope. Lithic and faunal analyses, as well as spatial analysis of the stratigraphic position of material recovered, indicate a clear separation of Mesolithic and Neolithic occupations. We present a new interpretation of the sequence of Holocene human occupations at Trou Al’Wesse in light of these data, arguing that the site was regularly occupied during the Early Mesolithic, forming a palimpsest of these visits, followed by an occupational hiatus and then reoccupation during the Late Mesolithic. The Early Neolithic is a separate occupation clearly unrelated to the Early Mesolithic underlying it, but ongoing fieldwork may recover data concerning the Final Mesolithic and its relation to the Early Neolithic at the site.     

Les premiers vertébrés et les premières étapes de l’évolution du crâne

The earliest vertebrates and the first steps of the evolution of the skull. Vertebrates are one of the few metazoan taxa, which display a well-corroborated phylogenetic pattern, a good and anatomically informative fossil record, and a relatively slow ontogenetic development. They are thus a favourite taxon for illustrating evolution as a historical process, although the stem of the vertebrate tree remains poorly documented by fossils, except for some Early Cambrian forms. Therefore, the characterization of the vertebrates now rests essentially on a small number of developmental characters, mostly involved in the rise of the skull, and whose precursors may occur in other chordates. The tree of the crown-group vertebrates also shows some major morphological gaps due to early extinctions, but a number of Palaeozoic stem gnathostome taxa helps in documenting the agnathan-gnathostome evolutionary transition. However, stem cyclostomes remain elusive.     

La redécouverte du site de Moulin Quignon (Somme) et les premiers Acheuléens du Nord-Ouest de l’Europe (650 ka)

New surveys were undertaken in Abbeville in 2016 and 2017 on the site of the Moulin Quignon discovered before 1850 by Boucher de Perthes, relocated thanks to the archival work carried out by MNHN researchers. This research led 150 years later to the rediscovery of this emblematic Paleolithic site. Test pits and extensive excavation have led to the discovery of alluvial levels in situ and a lithic series composed of 254 fragments, 15 cores and 5 bifaces. The cores and flakes attest to in situ debitage on flint nodules according mainly to unipolar and centripetal unifacial technology, except for one core, which indicates a management on several debitage surfaces. The bifaces are diversified morphologically and technically (shaping modes). They attest to a general management of the bifacial volume and geometry of the tool, to the care taken at the tip of the tool and to the regularisation of the often peripheral edges. They resemble those discovered by Boucher de Perthes in 1837–1868 and described in the past as “Abbevillian”. Stratigraphic and ESR age studies on quartz date human occupation between 670 and 650 ka. These artifacts belong to the earliest Acheulean occupation ever dated in the Somme basin and more generally north of the 50th parallel north. The lithic series discovered at Moulin Quignon is indisputable proof of the presence of human occupations dated at more than 650 ka in the Somme valley, a natural pathway to northern sectors, present-day Great Britain. This discovery thus ages (1) the age of the oldest occupation in the North of France (previously 550 ka) and (2) the age of the oldest bifaces for Northwest Europe (100 ka older than the bifaces in Great Britain).     

Le bassin lacustre miocène de Bes-Konak (anatolie-turquie): Géologie et introduction a la paléontologie des vertébrés

The tertiary lacustrine and marshy facies ofBes-Konak (Ankara-district) has provided a rich fauna of Vertebrates preserved as molds and casts in Diatomites and volcano-sedimentary beds.In this assemblage are: Cyprinid fishes (Leuciscus(P.) etiliusRückert Ulkümen) with among them a new species of Barbus, some Amphibians both Urodela (mature Triturinae) and Anura (larval forms of Pelobates sp. and mature Rana sp.), a Turtle (Chelydridae-Chelydropsis sp.) a Snake (Colubroïde-Colubridae or Viperidae) and Birds (among them a new species of cormorant).According to the others various data resulting from palaebotanical, palynological and structural investigations, this fauna is clearly suggestive of a lower or middle Miocene deposit. It supports readily the climatic features (local sub-tropical microclimate inside a regional hot-temperate context) as invertebrates, macro and microflora and sedimentology had already shown.Once more, it points out the peculiar trophic type of the limnic area of Bes-Konak and its evolution to a well-marked eutrophic condition.     

Sur l’existence de deux espèces d’Eremotherium E. rusconii (Schaub, 1935) et E. laurillardi (Lund, 1842) dans le Pléistocène supérieur du Brésil intertropical

Two recent discoveries in two “lagoas” of southeastern Piauí (North East of Brazil) allow us to describe and compare two very small-sized hemimandibles of two Megatheriidae. We attribute the first one, from the Lagoa dos Porcos, to a very young specimen of Eremotherium rusconii (Schaub, 1935), the gigantic Eremotherium well known in South America. We determine the other one, from the Lagoa do Quari, as an adult specimen of the small Eremotherium laurillardi (Lund, 1842). We confirm hereby our idea, written in 2000, of the reality of the latter species, which was not defined, like many authors think, on a juvenile tooth of the large species. The mandible of E. laurillardi is described for the first time. The mandible of the very young specimen of E. rusconii is also a rare piece.     

Intérêt d’une semi-quantification et d’une analyse statistique automatique pour l’interprétation de la tomoscintigraphie cérébrale de perfusion dans la maladie d’Alzheimer

IntroductionAs the visual interpretation of the brain perfusion SPECT for the diagnosis of Alzheimer's disease might be difficult, it is wished to benefit from techniques allowing to improve the diagnostic accuracy especially for the inexperienced readers.Materials and methodsThree readers retrospectively interpreted 77 ^99mTc-ECD SPECT studies within the context of suspected neurodegenerative disease. The probability of Alzheimer's disease was quoted from 1 to 5, and the optimum sensitivity and specificity values were determined from ROC curves. The readers also attributed a hypoperfusion score to 13 brain regions; a diagnosis was obtained from this semi-quantification using a simple logic rule. The SPECT scans were also analyzed using the Planet Neuro software and a diagnosis was reached from a threshold for 2 of the 90 analyzed regions. The gold standard was established by a comprehensive neurological evaluation with at least 5 years of follow-up.ResultsThe sensitivities and specificities of the three readers were 50 %, 56 %, 28 % and 76 %, 83 % and 90 %, respectively. Using the semi-quantification they were 50 %, 67 %, 61 % and 54 %, 85 %, 69 %. The results of two readers were more in agreement. Using the automatic quantification, sensitivity was 78 % and specificity 81 %.ConclusionThe semi-quantification seems to ameliorate the results of and the agreement between certain readers. However, the automatic quantification seems to be the only way of assisting all of the readers to improve their diagnostic performances.     

L’assemblage à Cardioceras (Cardioceras) cordatum (J. Sowerby, 1812) et sa place au sein de la succession ammonitique de l’Oxfordien Inférieur (Jurassique Supérieur). Apport des données ardennaises (Province Subboréale)

Some temporary outcrops at Villers-le-Tourneur/Neuvizy (Ardennes, France), made possible the observation and biostratigraphical dating of Uppermost Callovian to Early Middle Oxfordian poorly known formations. Especially, the “Oolite Ferrugineuse de Villers-le-Tourneur–Neuvizy” is a quite thick marly unit, yielding some silicified fossils well known since the XIX^th century. With details, the Formation displays the succession of several faunal associations, characterizing the main subzones of the Cordatum Zone (Late Lower Oxfordian) and the Plicatilis Zone (Early Middle Oxfordian). Amongst many other species, Cardioceras cordatum (Sowerby, 1812) corresponds to a rare taxon or morphotype, yielded by the bottom part of the Formation. Then, the ultimate Lower Oxfordian faunal association is dominated by ammonites related to C. persecans. These Early Oxfordian are widely dominated by the family Cardioceratidae, commonly associated with Aspidoceratidae; such a structure is related to the “subboreal associations”, typically represented in Great Britain. Immediately after the Middle Oxfordian boundary, some “subtethysian” ammonites (mainly Perisphinctidae), occur in a larger number without being dominant, that emphasizing the northern location of the Ardennes margin. Then locally, two faunal associations succeed, which are characterized by C. cordatiforme (with Euaspidoceras perarmatum), and C. densiplicatum, respectively. Both are typical associations of the Vertebrale Subzone (Early Middle Oxfordian).     

Archéologie de l’art rupestre au Mato Grosso (Brésil) : la Chapada dos Guimarães

As part of the research program “Archaeology of rock art in Mato Grosso: the Chapada dos Guimarães National Park (Cuiabá, Brazil)” placed under the coordination of Patrick Paillet and Veronica Wesolowski, an integrated and interdisciplinary approach to the territory still largely unpublished rock art of the Chapada dos Guimarães, has been undertaken since 2020 by combining strictly archaeological research (surveys, excavations and prospecting-inventories), rock art studies (analysis and graphic, photographic and photogrammetric recording of representations) and geological analyzes and, to define and characterize the structure of its ornamented landscapes. Our program is an extension of other projects carried out from 1983 to 2013 under the direction of Agueda Vilhena-Vialou, Denis Vialou and Levy Figuti in the region of the Cidade de Pedra near Rondonópolis and at Santa Elina in the Serra das Araras (Jangada). The region of the Chapada dos Guimarães National Park (PNCG) was the subject of exploration and partial studies between 2017 and 2019 under the direction of Caroline Bachelet within the framework of the program “Prehistory and Paleoenvironments in the Pantanal region (Mato Grosso, Brazil)”. The pursuit of archaeological research in the PNCG contributes to better defining the chronology and the dynamics of occupations at local and regional scales, to characterizing chrono-culturally the settlements and their variability in the region, extending from the Rio Vermelho in the south to the Rio Cuiabá in the north, and to understand the processes of settlement and/or mobility of past populations along the firm lands and especially the hydrographic systems that border the floodplains of the Pantanal and which constitute the main routes of population movement.     

Effets de l’âge et du genre sur la perfusion cérébrale régionale étudiée par deux méthodes d’analyse statistique voxel-par-voxel

Fully automated analysis programs have been applied more and more to aid for the reading of regional cerebral blood flow SPECT study. They are increasingly based on the comparison of the patient study with a normal database. In this study, we evaluate the ability of Three-Dimensional Stereotactic Surface Projection (3D-SSP) to isolate effects of age and gender in a previously studied normal population. The results were also compared with those obtained using Statistical Parametric Mapping (SPM99).MethodsEighty-nine ^99mTc-ECD-SPECT studies performed in carefully screened healthy volunteers (46 females, 43 males; age 20–81 years) were analysed using 3D-SSP. A multivariate analysis based on the general linear model was performed with regions as intrasubject factor, gender as intersubject factor and age as covariate.ResultsBoth age and gender had a significant interaction effect with regional tracer uptake. An age-related decline (p < 0.001) was found in the anterior cingulate gyrus, left frontal association cortex and left insula. Bilateral occipital association and left primary visual cortical uptake showed a significant relative increase with age (p < 0.001). Concerning the gender effect, women showed higher uptake (p < 0.01) in the parietal and right sensorimotor cortices. An age by gender interaction (p < 0.01) was only found in the left medial frontal cortex. The results were consistent with those obtained with SPM99.Conclusion3D-SSP analysis of normal rCBF variability is consistent with the literature and other automated voxel-based techniques, which highlight the effects of both age and gender.     

Découverte de vertébrés aquatiques présumés paléocènes dans les Andes septentrionales de Bolivie (Rio Suches,synclinorium de Putina)

The teleost fish Brychaetus and a dyrosaurid crocodilewere recognized among the aquatic vertebrates recently discovered in the northern area of the Titicaca lake (Bolivia). These fossils allow the presumption of a Paleocene age for the vertebrate bearing formation. The structural interpretation of this chronological data is discussed.     

Nouvelles données sur l’évolution paléoclimatique de l’époque magdalénienne,d’après l’étude lithostratigraphique du Roc-aux-Sorciers (Angles-sur-l’Anglin,Vienne, France)

Situated a few kilometres from Angles-sur-Anglin (Vienne, France), the Roc-aux-Sorciers cave has yielded in 1927 and 1950 industry of the Middle and Upper Magdalenian periods. Our analyses of the sedimentary filling, dated from isotope stage 2, demonstrate the existence of two climatic sequences in the six ensembles defined during the excavations. A first sequence, at the base of the cave filling, corresponds to the occupation levels of the Middle Magdalenian and of the early Upper Magdalenian. At that time, the climate was globally cold and particularly humid, a conclusion that does not support Bastin's 1975 hypothesis on the oscillation of Angles-sur-Anglin, which postulates a mild and humid climate. In fact, the climate evolved progressively towards a slight warming from the base to the top of the stratigraphy. During the second sequence, corresponding to the occupation period of the Upper Magdalenian, the relatively stable climate was slightly warmer and quite humid. Stratigraphical and sedimentological data thus provide new information on the conditions under which the filling was deposited and on the palaeoclimatology of the Poitou-Charentes region during Magdalenian occupation.     

Synthèse sur la diversité des préservations végétales du site d’Archingeay-Les Nouillers (France) : un Konservat-Lagerstätte pour les flores de l’Albien-Cénomanien

Since the end of the XXth century, the palaeontological site of Archingeay-Les Nouillers (Charente-Maritime, western France) continued to afford Albian-Cenomanian (ca 93–113 Ma) plant meso- and macroremains. The successive excavations provided numerous specimens useful for the reconstruction of mid-Cretaceous coastal forest ecosystems. However, one of the most remarkable features of this locality is the diversity of plant preservations. Unique in Europe from this point of view, the fossiliferous site of Archingeay-Les Nouillers yielded compressions with or without cuticle, impressions/imprints, and silicified permineralizations/petrifications. The quality of the silicified tissues and the cell preservation allow this locality to be considered as a plant Konservat-Lagerstätte.