On the quantification of [F-18]MPPF binding to 5-HT1A receptors in the human brain

Previous studies have shown that 4-(2 ' -methoxyphenyl)-1 [2 '-(N-2 "- pyridinyl)-p- [F-18]fluorobenzamido]ethylpiperazine ([F-18]MPPF) binds with high selectivity to serotonin (5-HT1A) receptors in man. However, in these studies, the calculation of the binding potential (BP, which equals receptor density divided by equilibrium dissociation constant) used a metabolite-corrected arterial input. The aim of this study was to determine whether metabolite correction and arterial sampling are essential for the assessment of BP. Methods: Five analytic methods using full datasets obtained from 6 healthy volunteers were compared. In addition, the clinical applicability of these methods was appraised. Three methods were based on Logan analysis of the dynamic PET data using metabolite-corrected and uncorrected arterial plasma input and cerebellar input. The other 2 methods consisted of a simplified reference tissue model and standard compartmental modeling. Results: A high correlation was found between BP calculated with Logan analysis using the metabolite-corrected plasma input (used as the reference method for this study) and Logan analysis using either the uncorrected arterial plasma input (r(2) = 0.95, slope = 0.85) or cerebellar input (r(2) = 0.98, slope = 0.91), A high correlation was also found between our reference method and the simplified reference tissue model (r(2) = 0.94, slope = 0.92). In contrast, a poor correlation was observed between our reference method and the standard compartmental model (r(2) = 0.45, slope = 1.59). Conclusion: These results indicate that neither metabolite analysis nor arterial sampling is necessary for clinical evaluation of BP in the human brain with [18F]MPPF. Both the Logan analysis method with cerebellar input and the simplified reference tissue method can be applied clinically

On the quantification of [F-18]MPPF binding to 5-HT1A receptors in the human brain

Previous studies have shown that 4-(2 ' -methoxyphenyl)-1 [2 '-(N-2 "- pyridinyl)-p- [F-18]fluorobenzamido]ethylpiperazine ([F-18]MPPF) binds with high selectivity to serotonin (5-HT1A) receptors in man. However, in these studies, the calculation of the binding potential (BP, which equals receptor density divided by equilibrium dissociation constant) used a metabolite-corrected arterial input. The aim of this study was to determine whether metabolite correction and arterial sampling are essential for the assessment of BP. Methods: Five analytic methods using full datasets obtained from 6 healthy volunteers were compared. In addition, the clinical applicability of these methods was appraised. Three methods were based on Logan analysis of the dynamic PET data using metabolite-corrected and uncorrected arterial plasma input and cerebellar input. The other 2 methods consisted of a simplified reference tissue model and standard compartmental modeling. Results: A high correlation was found between BP calculated with Logan analysis using the metabolite-corrected plasma input (used as the reference method for this study) and Logan analysis using either the uncorrected arterial plasma input (r(2) = 0.95, slope = 0.85) or cerebellar input (r(2) = 0.98, slope = 0.91), A high correlation was also found between our reference method and the simplified reference tissue model (r(2) = 0.94, slope = 0.92). In contrast, a poor correlation was observed between our reference method and the standard compartmental model (r(2) = 0.45, slope = 1.59). Conclusion: These results indicate that neither metabolite analysis nor arterial sampling is necessary for clinical evaluation of BP in the human brain with [18F]MPPF. Both the Logan analysis method with cerebellar input and the simplified reference tissue method can be applied clinically

Roman aqueduct maintenance in the water supply system of Divona, France

Carbonate deposits formed in Roman aqueducts provide a window onto the environment and water management in antiquity. These laminated archives precipitated over a period of decades to centuries and are a potential high-resolution source of unwritten history. However, their use as environmental archives is hampered by local and partial removal during maintenance work in some aqueducts. This apparent problem, however, creates a unique opportunity to study Roman water management. We present the discovery of traces of regular maintenance in carbonate deposits of the Roman aqueduct of Divona (Cahors, France). The main objective of this study is to determine the periodicity of local carbonate removal and repairs in this aqueduct. Traces such as tool marks, calcite deformation twins, debris from cleaning and repairs are attested in the deposits as proof of periodic manual carbonate removal by Roman maintenance teams. The δ 18 O profile, recording at least 88 years of deposition, shows that maintenance work was done at intervals of 1–5 years. The undisturbed periodicity of the δ 18 O profile indicates that work was carried out rapidly and never in summer, consonant with the advice of the Roman author Frontinus about maintenance of the aqueducts of the city of Rome. Maintenance intervals lengthened and cleaning became less frequent close to the final years of the aqueduct. This change in maintenance policy gives insight into changing local population and socioeconomic dynamics in late antiquity

Late Quaternary dynamics of the Lambert Glacier-Amery Ice Shelf system, East Antarctica

The Lambert Glacier-Amery Ice Shelf system (LGAISS) is the largest outlet glacier system in East Antarctica but its response to past climate variability is poorly constrained. In this study, we explore its dynamics over the last ∼520 thousand years using new high-resolution sedimentary records retrieved off Prydz Bay. Episodic occurrences of iceberg rafted debris indicate a dynamic ice sheet throughout this interval, while changes in clay mineral compositions provide detailed evidence on the waxing and waning of the LGAISS. Our data indicate that advance and retreat of the LGAISS was sensitive to oceanic forcing, but also responded to local summer insolation when insolation peaks combined with interglacial sea level high stands. Subglacial bed topography may have played an additional role in modulating the LGAISS behaviour, which could explain sectoral differences in the response of the East Antarctic Ice Sheet to climate change. Overall, our records indicate that the LGAISS advanced more extensively during previous late Quaternary glacial periods than during Marine Isotope Stages 2 and 4. Furthermore, the LGAISS retreated more significantly than present during Marine Isotope Stage 13, and only moderately during Marine Isotope Stage 7, which suggests that the duration of warm climatic states could be a key factor affecting the dynamics of the East Antarctic Ice Sheet

Reconstructing the hydraulics of the world’s first industrial complex, the second century CE Barbegal watermills, France

The Barbegal watermill complex, a unique cluster of 16 waterwheels in southern France, was the first known attempt in Europe to set up an industrial-scale complex of machines during the culmination of Roman Civilization in the second century CE. Little is known about the state of technological advance in this period, especially in hydraulics and the contemporary diffusion of knowledge. Since the upper part of the Barbegal mill complex has been destroyed and no traces of the wooden machinery survived, the mode of operation of these mills has long remained elusive. Carbonate incrustations that formed on the woodwork of the mills were used to reconstruct its structure and function, revealing a sophisticated hydraulic setup unique in the history of water mills. The lower mills used an elbow shaped flume to bring water onto overshot millwheels. This flume was specially adapted to the small water basins and serial arrangement of the mills on the slope. Carbonate deposits from ancient water systems are therefore a powerful tool in archaeological reconstructions and provide tantalizing insights into the skills of Roman engineers during a period of history that is the direct predecessor of our modern civilization

Mens (dood of levend) of dier? Attitudes over en morele implicaties van orgaanverwerving

Dit rapport is het verslag van een verkennende studie naar attitudes met betrekking tot orgaandonatie, en de morele implicaties hiervan. Psychologisch en ethisch onderzoek vullen elkaar in dit rapport aan. Er wordt aandacht geschonken aan twee ontwikkelingen op het gebied van orgaanverwerving: de toename van orgaandonaties bij leven, met name bij donatie van nieren en de verminderde interesse in de ontwikkeling van xenotransplantatie. Het psychologische deel van het rapport valt uiteen in literatuurstudie en eigen empirisch onderzoek. In dit deel wordt zowel de attitude van patiënten als de psychosociale belasting beschreven voor xenotransplantatie en voor nierdonatie bij leven. Patiënten zien nierdonatie bij leven in het algemeen als een wenselijk alternatief voor de wachtlijstsituatie, terwijl men in dit opzicht een stuk terughoudender is ten aanzien van xenotransplantatie. Om te bepalen welke rol van overheid, zorgverleners en onderzoekers gepast is, is het van belang te begrijpen hoe persoonlijke overtuigingen worden gevormd en kunnen veranderen. In het ethische, tweede deel van het rapport wordt dan ook meer aandacht besteed aan de verschillende motivaties voor orgaandonatie. Bij postmortale donatie worden vooral waarden als vrijwilligheid, anonimiteit en altruïsme genoemd. Bij familiedonatie doen begrippen als vanzelfsprekende solidariteit, morele plicht en lotsverbondenheid hun intrede, maar ook begrippen als eigenbelang, afhankelijkheid en wederkerigheid. Onderzocht wordt hoe de verschillende donatievormen zich tot elkaar verhouden, teneinde te bepalen op welke motivaties voor orgaandonatie we als maatschappij een beroep willen doen. Op dit punt wordt expliciet ingegaan op de rol van de overheid. Tevens is er een meer losstaand hoofdstuk gewijd aan commerciële orgaandonatie

De Behoefte aan Psychosociale Steun bij Deelnemers aan het Nederlandse Cross-over Transplantatie Programma

Final technical report of the project.The Dutch kidney exchange donation program started in January 2004. A literature review has shown that several factors of the exchange program could influence the psychological well being of participants, such as the loss of the possibility of a “medical excuse” for unwilling donors and the issue of anonymity. However, these factors have not been the subject of empirical study yet. We therefore studied these factors to determine whether additional psychosocial support is necessary for donors and recipients in the Dutch kidney exchange program. We used structured interviews for all 48 donors and recipients that had undergone exchange donation/ transplantation in 2004. A psychologist interviewed the participants before and 3 months after transplantation. We included a comparison group of 48 donors and recipients participating in the regular living kidney donation program. Donors did not experience additional pressure to donate due to the exchange donation. Most participants preferred anonymity between the couples. We found few needs for additional emotional support. In this respect the exchange group did not differ from the comparison group. We conclude that the psychosocial support offered to exchange couples can be comparable to the support normally offered to participants in the regular living kidney donation program