Cowries in the archaeology of West Africa: the present picture

Despite the perceived importance of cowrie shells as indicators of long-distance connections in the West African past, their distribution and consumption patterns in archaeological contexts remain surprisingly underexplored, a gap that is only partly explicable by the sparse distribution of archaeological sites within the sub-continent. General writings on the timeline of importation of cowries into West Africa often fail to take into account the latest archaeological evidence and rely instead on accounts drawn from historical or ethnographic documents. This paper is based on a first-hand assessment of over 4500 shells from 78 sites across West Africa, examining chronology, shell species and processes of modification to assess what distribution patterns can tell us about the history of importation and usage of cowries. These first-hand analyses are paralleled by a consideration of published materials. We re-examine the default assumption that two distinct routes of entry existed — one overland from North Africa before the fifteenth century, another coming into use from the time sea links were established with the East African coast and becoming predominant by the middle of the nineteenth century. We focus on the eastern part of West Africa, where the importance of imported cowries to local communities in relatively recent periods is well known and from where we have a good archaeological sample. The conclusion is that on suitably large assemblages shell size can be an indication of provenance and that, while the present archaeological picture seems largely to confirm historical sources, much of this may be due to the discrepancy in archaeological data available from the Sahara/Sahel zone compared to the more forested regions of the sub-continent. Future archaeological work will clarify this matter

On the typology and the worship status of sacred trees with a special reference to the Middle East

This article contains the reasons for the establishment of sacred trees in Israel based on a field study. It includes 97 interviews with Muslim and Druze informants. While Muslims (Arabs and Bedouins) consider sacred trees especially as an abode of righteous figures' (Wellis') souls or as having a connection to their graves, the Druze relate sacred trees especially to the events or deeds in the lives of prophets and religious leaders. A literary review shows the existence of 24 known reasons for the establishment of sacred trees worldwide, 11 of which are known in Israel one of these is reported here for the first time. We found different trends in monotheistic and polytheistic religions concerning their current worship of sacred trees

p53 Status and Tumor Cell Response to Radioimmunotherapy using 125I-mAbs

Introduction: While radioimmunotherapy (RIT) of non-Hodgkins B-cell lymphoma with Zevalin® and Bexxar ® (anti-CD20 labelled to 90Y or 131I) has demonstrated its efficiency. However, new strategies must be developed in order to treat solid tumours by RIT. In a previous study, we proposed to use the highly cytotoxic Auger electrons emitted by 125I to overcome the radioresistance of solid tumours. We showed that tumour killing achieved with non-internalizing labeled monoclonal antibodies (mAbs) is more significant than that of internalizing 125I-mAbs. This suggests that while the nucleus remains the main target of irradiation, the membrane is also a sensitive target. In the present study, we investigated the role of the nuclear p53 protein and that of ceramide, a major mediator of apoptosis, in the cellular response to 125I mAbs exposure. Material and Methods: Two carcinoma colic cell lines, H3E5 (p53 wt) and HCT116-KO (p53 deficient) expressing cell surface HER1 and CEA receptors were exposed for 2 days to increasing activities (04 MBq/mL) of either internalizing (anti-HER1) or non-internalizing (anti-CEA) 125I-mAbs. Survival was assessed by standard clonogenic assay and dosimetry was investigated using the MIRD scheme. For this purpose, uptake of radioactivity per cell was measured, and S-factors for 125I were specifically calculated for cell surface and cell cytoplasm localisation. Then, first experiments were carried out with alkaline comet assay to observe DNA damage from RIT. Results: For both cell lines, we confirmed that the toxicity due to 125I decays was greater with non-internalizing rather than with internalizing 125I-mAbs. Moreover, we showed that H3E5 cell line was more sensitive to X-ray external beam irradiation rather than HCT116-KO. By contrast, for both 125I localisations, preliminary experiment showed no significant difference on the survival between the two cell lines. These results would indicate that p53 status does not mediate the response to RIT with Auger electrons. A tentative explanation may involve the low dose rate induced by RIT. Under these conditions, no detectable DNA damage was measured by the alkaline comet assay. Conclusion: Our preliminary results seem to indicate that p53 status does not interfere with tumour cell response to RIT. Ongoing experiments are assessing the role of ceramide as a mediator of apoptosis, to explain membrane irradiation efficiency

Assessment of a fully 3D Monte Carlo reconstruction method for preclinical PET with iodine-124

International audienceIodine-124 is a radionuclide well suited to the labeling of intact monoclonal antibodies. Yet, accurate quantification in preclinical imaging with I-124 is challenging due to the large positron range and a complex decay scheme including high-energy gammas. The aim of this work was to assess the quantitative performance of a fully 3D Monte Carlo (MC) reconstruction for preclinical I-124 PET. The high-resolution small animal PET Inveon (Siemens) was simulated using GATE 6.1. Three system matrices (SM) of different complexity were calculated in addition to a Siddon-based ray tracing approach for comparison purpose. Each system matrix accounted for a more or less complete description of the physics processes both in the scanned object and in the PET scanner. One homogeneous water phantom and three heterogeneous phantoms including water, lungs and bones were simulated, where hot and cold regions were used to assess activity recovery as well as the trade-off between contrast recovery and noise in different regions. The benefit of accounting for scatter, attenuation, positron range and spurious coincidences occurring in the object when calculating the system matrix used to reconstruct I-124 PET images was highlighted. We found that the use of an MC SM including a thorough modelling of the detector response and physical effects in a uniform water-equivalent phantom was efficient to get reasonable quantitative accuracy in homogeneous and heterogeneous phantoms. Modelling the phantom heterogeneities in the SM did not necessarily yield the most accurate estimate of the activity distribution, due to the high variance affecting many SM elements in the most sophisticated SM

Evidence of Extranuclear Cell Sensitivity to Alpha-particle Radiation Using a Microdosimetric Model - I - Presentation and Validation of a Microdosimetric Model

For short-range high-LET radiation therapy, the biological effects are strongly affected by the heterogeneity of the specific energy distribution delivered to tumor cells. Three-dimensional information at the cellular level is ideal for this type of study, but it is extremely difficult to obtain. In this paper, a novel microdosimetry analysis, which obtains the specific energy distribution directly from the morphological information in individual autoradiographic sections, is applied to in vivo human glioblastoma multiforme and normal brain tissue in boron neutron capture therapy. Specific energy distributions were obtained for both specimens, and they are consistent with a uniform boron microdistribution. We also used a biophysical model for cell survival analysis based on the specific energy and were able to bridge it with the model based on the corresponding macroscopic parameter (dose) using existing experimental data. The survival constant for the microscopic model was determined; cell survival curves were predicted for uniform and non-uniform source distributions, i.e., sources and cell nuclei bound together totally or only partially. The results indicate that the behavior of the survival curve can vary widely, which may have important clinical implications.JRC.E.5-Nuclear chemistr