Small angle X-ray diffraction studies on the topography of cannabinoids in synaptic plasma membranes

In a previous publication, we have described in detail how we used small angle x-ray diffraction to determine the topography of (-)-Δ8-tetrahydrocannabinol (Δ8-THC) in dimyristoylphophatidylcholine (DMPC) bilayers, and to deduce the conformation of the THC side chain by using the iodo-analog (5′-I-Δ8-THC) in the model membrane. We have now extended our studies to synaptic plasma membrane systems where the cannabinoids are believed to exert part of their pharmacological effects. Synaptic plasma membranes (SPM) were isolated from fresh bovine brains and Δ8-THC was incorporated into the membranes. By comparing the electron density profiles of drug free and drug-containing SPM preparations, we observed an electron density increase due to the presence of Δ8-THC in a region centered at 9.2 Å from the terminal methyl groups of the membrane bilayer. In an attempt to dissect the effects of different membrane components on the topography of Δ8-THC, we carried out parallel experiments using membrane preparations from the synaptosomal membrane total lipid extract (TLX) as well as from bovine brain phosphatidyl choline extract (PCX) containing 30 mole percent cholesterol (Chol). Our results regarding the topography of Δ8-THC and 5′-I-Δ8-THC in these lipid membranes show that the TLX bilayer simulates the natural membrane environment very closely whereas in the PCX/Chol bilayer Δ8-THC resides at a location approximately 4 Å closer to the membrane interface, similar to that found in our previous study using DMPC model membrane. These x-ray diffraction results provide insights regarding the location of the binding sites on the cannabinoid receptor and indicate that preparations of the total lipid extract from synaptosomal membranes duplicate very well the properties of the intact membrane preparation

Finding Oxford’s medieval Jewry using organic residue analysis, faunal records and historical documents

Food is often one of the most distinctive expressions of social, religious, cultural or ethnic groups. However, the archaeological identification of specific religious dietary practices, including the Jewish tradition of keeping kosher, associated with ritual food practices and taboos, is very rare. This is arguably one of the oldest known diets across the world and, for an observant Jew, maintaining dietary laws (known as Kashruth) is a fundamental part of everyday life. Recent excavations in the early medieval Oxford Jewish quarter yielded a remarkable assemblage of animal bones, marked by a complete absence of pig specimens and a dominance of kosher (permitted) birds, domestic fowl and goose. To our knowledge, this is the first identification of a Jewish dietary signature in British zooarchaeology, which contrasted markedly with the previous Saxon phase where pig bones were present in quantity and bird bones were barely seen. Lipid residue analysis of pottery from St Aldates showed that vessels from the possible Jewish houses were solely used to process ruminant carcass products, with an avoidance of pig product processing, correlating well with the faunal data. In contrast, lipid analysis of pottery from comparative assemblages from the previous Saxon phase at the site and a contemporaneous site in the city, The Queen’s College, shows that the majority of these vessels appear to have been used to process mixtures of both ruminant and non-ruminant (pig) products. Here, the combination of organic residue analysis, site excavation and animal and fish bone evidence was consistent with the presence of Jewish houses in eleventh- and twelfth-century St Aldates, Oxford, hitherto only suspected through documentary information. This is the first identification of specific religious dietary practices using lipid residue analysis, verifying that, at least 800 years ago, medieval Jewish Oxford communities practised dietary laws known as Kashruth

Assessing the Validity of Adult-derived Prognostic Models for Primary Sclerosing Cholangitis Outcomes in Children

Background:Natural history models for primary sclerosing cholangitis (PSC) are derived from adult patient data, but have never been validated in children. It is unclear how accurate such models are for children with PSC.Methods:We utilized the pediatric PSC consortium database to assess the Revised Mayo Clinic, Amsterdam-Oxford, and Boberg models. We calculated the risk stratum and predicted survival for each patient within each model using patient data at PSC diagnosis, and compared it with observed survival. We evaluated model fit using the c-statistic.Results:Model fit was good at 1 year (c-statistics 0.93, 0.87, 0.82) and fair at 10 years (0.78, 0.75, 0.69) in the Mayo, Boberg, and Amsterdam-Oxford models, respectively. The Mayo model correctly classified most children as low risk, whereas the Amsterdam-Oxford model incorrectly classified most as high risk. All of the models underestimated survival of patients classified as high risk. Albumin, bilirubin, AST, and platelets were most associated with outcomes. Autoimmune hepatitis was more prevalent in higher risk groups, and over-weighting of AST in these patients accounted for the observed versus predicted survival discrepancy.Conclusions:All 3 models offered good short-term discrimination of outcomes but only fair long-term discrimination. None of the models account for the high prevalence of features of autoimmune hepatitis overlap in children and the associated elevated aminotransferases. A pediatric-specific model is needed. AST, bilirubin, albumin, and platelets will be important predictors, but must be weighted to account for the unique features of PSC in children. © ESPGHAN and NASPGHAN. All rights reserved

The Sclerosing Cholangitis Outcomes in Pediatrics (SCOPE) Index: A Prognostic Tool for Children

Background and Aims: Disease progression in children with primary sclerosing cholangitis (PSC) is variable. Prognostic and risk-stratification tools exist for adult-onset PSC, but not for children. We aimed to create a tool that accounts for the biochemical and phenotypic features and early disease stage of pediatric PSC. Approach and Results: We used retrospective data from the Pediatric PSC Consortium. The training cohort contained 1,012 patients from 40 centers. We generated a multivariate risk index (Sclerosing Cholangitis Outcomes in Pediatrics [SCOPE] index) that contained total bilirubin, albumin, platelet count, gamma glutamyltransferase, and cholangiography to predict a primary outcome of liver transplantation or death (TD) and a broader secondary outcome that included portal hypertensive, biliary, and cancer complications termed hepatobiliary complications (HBCs). The model stratified patients as low, medium, or high risk based on progression to TD at rates of <1%, 3%, and 9% annually and to HBCs at rates of 2%, 6%, and 13% annually, respectively (P < 0.001). C-statistics to discriminate outcomes at 1 and 5 years were 0.95 and 0.82 for TD and 0.80 and 0.76 for HBCs, respectively. Baseline hepatic fibrosis stage was worse with increasing risk score, with extensive fibrosis in 8% of the lowest versus 100% with the highest risk index (P < 0.001). The model was validated in 240 children from 11 additional centers and performed well. Conclusions: The SCOPE index is a pediatric-specific prognostic tool for PSC. It uses routinely obtained, objective data to predict a complicated clinical course. It correlates strongly with biopsy-proven liver fibrosis. SCOPE can be used with families for shared decision making on clinical care based on a patient’s individual risk, and to account for variable disease progression when designing future clinical trials. © 2020 by the American Association for the Study of Liver Diseases