Use of organ-culture, irradiation and adoptive-transfer to investigate the role of the xenopus thymus in t lymphocyte development

This Thesis attempts to develop an amphibian model system for exploring the role of the thymus, particularly its stromal cells, in the acquisition of allotolerance. Inbred, clonal and cytogenetically- marked Xenopus are used in this work. The initial experiments (Chapter 2) describe in vitro attempts to deplete the larval and post-metamorphic thymus of its lymphocyte component, while leaving its stromal elements intact. The histologic effects of deoxyguanosine-treatment and 6 -irradiation on the organ-cultured thymus are examined in wax sections. In vivo whole-body irradiation (3000R) and subsequent in situ residence for ~ 10 days proves the most successful technique for depleting thymic lymphocyte numbers from the froglet thymus (Chapter 3). This technique provides a lymphocyte-depleted thymus with a fairly normal 3-d stromal network. Furthermore, these thymuses show no sign of lymphocyte regeneration when organ-cultured for ~ 2 weeks. In Chapter 3, 1 um sections and electron microscopy of plastic-embedded sections provides a detailed picture of the froglet thymus following irradiation. Chapters 4 and 5 employ ploidy labelling and the X. borealis (quinacrine-fluorescence) cell marker system, to show that larval and adult (normal or in vivo irradiated) thymuses, implanted to early- thymectomized Xenopus (MHC-compatible. or -incompatible), become infiltrated by host lymphoid cells, the thymic epithelium remaining donor-derived. A time-course study shows that for normal thymus implants, host cells begin to immigrate in good number only after metamorphosis is complete; with these thymus implants, donor-derived lymphocytes can still be found in the blood and spleen of thymectomized hosts several months post-implantation. Irradiated thymus implants attracted host cells more rapidly, their lymphoid complement becoming almost exclusively host-type within 2 weeks post-implantation when animals were at a late larval stage of development. Despite rapid colonization of irradiated implants by host lymphoid cells, these thymuses degenerate soon after metamorphosis, presumably due to irradiation damage of stromal elements. The experiments in Chapter 6 compare the proliferative responses of thymocytes from normal and organ-cultured thymuses. The technical conditions (e.g. cell numbers per well) for obtaining good stimulation indices with T cell mitogens, and in mixed leucocyte culture (MLC), are examined. Thymocytes organ-cultured for 12 days generally display elevated 3HTdR uptake compared with cells tested straight from the animal. Both control and experimental (mitogen- or alloantigen-treated) cultures of organ-cultured thymocytes show these elevated DPM. Surprisingly, in vivo-irradiated, organ-cultured thymocytes, are still stimulated by phytohaemagglutinin (PHA)-treatment. Chapter 7 investigates in vitro T-cell proliferative responses of splenocytes and thymocytes in allothymus-implanted, early- thymectomized Xenopus. Splenocyte reactivity to PHA and to third- party alloantigens (in MLC) is restored when normal allogeneic thymus is implanted ("adoptively-transferred"). However, MLC reactivity of thymocytes and splenocytes to thymus-donor strain cells is generally lacking; allothymus-implanted animals are also tolerant to thymus-donor strain skin grafts. Unfortunately, thymectomized animals implanted with in vivo irradiated, allothymuses died prior to in vitro assaying. Preliminary attempts to generate supernatants (by treating cultured splenocytes with PHA and/or phorbol myristate acetate) that would routinely enhance T cell proliferative responses of thymocytes, are outlined in Chapter 8. General conclusions to be drawn from this Thesis and suggestions for future work with this amphibian model are to be found in Chapter 9

A taphonomic approach to reconstructing Upper Palaeolithic hunter-gatherer fishing strategies. A load of old trout!

In many cases in the past fish bones recovered during archaeological excavations at Upper Palaeolithic sites were often assumed to result from human activity without any consideration for alternate accumulation processes. Many of these assemblages had not been analysed in a scientifically rigorous manner, with some receiving no consideration at all. A review of current evidence and results of new analyses indicate that salmonids (salmon and trout) are the most frequently recorded fish at the European Palaeolithic cave sites. Two potential accumulation agents for fish remains were explored: brown bears (Ursus arctos) and eagle owls (Bubo bubo). Controlled feeding experiments integrated with ecological studies indicate that salmonid remains survive the digestive systems of both species and result in distinctive patterning in assemblage characteristics. Post-depositional taphonomic processes, such as trampling, also produce distinct taphonomic signatures and are an agent of differential inter-species preservation. A thorough consideration of depositional and post-depositional processes of archaeological assemblages in central Italy (Grotta di Pozzo, Maritza, La Punta and Ortucchio) and Spain (El Juyo, Altamira, Salitre, Castillo and Rascaño) shows that the fish remains from these sites result from human activity. The overrepresentation of cranial elements at the Italian sites suggest that fish were processed by removing the head to perhaps smoke or dry before transportation to other locations for consumption. This research lead to improved methods of analysis, and thus enhanced understanding of the role of fishing and fish consumption in Upper Palaeolithic hunter-gatherer societies

Labanotation of Latvian Folk Dance: Tracing the Story of Cūkas Driķos Through the Notation Process

There are many versions of traditional Latvian dances, so determining what to notate becomes part of the process. Tracing the story of the dance Cūkas driķos [Pigs in a Buckwheat Field] for notation purposes became as valuable as the Labanotation score that resulted. The investigation began with a presentational, newer version of the dance, which led to examining the related contemporary, social versions. These were then compared to descriptions in field notes and historic folk dance publications to try to discern the most traditional version(s). In this journey, Labanotation helped illuminate distinctions between the presentational and the participatory versions, as well as clearly define standard participatory variations and their relationship to related documented dances. In this manner, the search for what to notate was aided by the notation process itself. Ideally, the Labanotation scores developed through this research process can then become another, perhaps more precise and clear, primary source for understanding traditional Latvian folk dances

Low-level lithium in drinking water and subsequent risk of dementia:Cohort study

Background: Lithium, a mood stabilizer, is known to exhibit neuroprotective effects in animal models and may have anti-dementia effects. Aims: We used data from Scottish Mental Survey 1932, a population-based cohort study, to investigate the association between lithium in drinking water and dementia rate in humans. Method: Lithium levels in drinking water from 285 sampling sites across Scotland dating from 2014 were obtained from the sole public water provider (Scottish Water). Dementia and non dementia cases were identified from cohort data by electronic health records until 2012, and linked to postcode. Results: The mean lithium level at all sampling sites was 1.45 μg /L (SD 1.83, range 0.5-18.2) and was 1.26 (SD 0.63, range 0.55-9.19) for sites matched to participant data. Of 37,597 study members, 3,605 developed dementia until June 2012. . Lithium levels were positively associated with the risk of dementia in women (highest in second quartile, HR 1.17, 95%CI 1.04-1.32), but there was no relationship in men (highest in second quartile, HR 0.95, 95% CI 0.81-1.12). The pattern of association was explored further by decile, and in females there was an association between lithium level and increased dementia risk compared to the lowest decile (0.55-0.68 μg/L) in all deciles except the highest, corresponding with lithium levels 0.68-2.1 μg/L. Conclusions: Lithium levels in drinking water are very low across Scotland which limited detection of potential effect. Our results do not support an association between extremely low levels of lithium and later dementia risk.. We found a trend to increased risk in females at lithium levels below but not above 2.1 μg/L

Aluminium and fluoride in drinking water in relation to later dementia risk

BACKGROUND: Environmental risk factors for dementia are poorly understood. Aluminium and fluorine in drinking water have been linked with dementia but uncertainties remain about this relationship. AIMS: In the largest longitudinal study in this context, we set out to explore the individual effect of aluminium and fluoride in drinking water on dementia risk and, as fluorine can increase absorption of aluminium, we also examine any synergistic influence on dementia. METHOD: We used Cox models to investigate the association between mean aluminium and fluoride levels in drinking water at their residential location (collected 2005–2012 by the Drinking Water Quality Regulator for Scotland) with dementia in members of the Scottish Mental Survey 1932 cohort who were alive in 2005. RESULTS: A total of 1972 out of 6990 individuals developed dementia by the linkage date in 2012. Dementia risk was raised with increasing mean aluminium levels in women (hazard ratio per s.d. increase 1.09, 95% CI 1.03–1.15, P < 0.001) and men (1.12, 95% CI 1.03–1.21, P = 0.004). A dose-response pattern of association was observed between mean fluoride levels and dementia in women (1.34, 95% CI 1.28–1.41, P < 0.001) and men (1.30, 95% CI 1.22–1.39, P < 0.001), with dementia risk more than doubled in the highest quartile compared with the lowest. There was no statistical interaction between aluminium and fluoride levels in relation with dementia. CONCLUSIONS: Higher levels of aluminium and fluoride were related to dementia risk in a population of men and women who consumed relatively low drinking-water levels of both. DECLARATION OF INTEREST: NONE

Common mental disorders and mortality in the West of Scotland Twenty-07 Study: comparing the General Health Questionnaire and the Hospital Anxiety and Depression Scale

Background While various measures of common mental disorders (CMD) have been found to be associated with mortality, a comparison of how different measures predict mortality may improve our understanding of the association. This paper compares how the Hospital Anxiety and Depression Scale (HADS) and the 30-item General Health Questionnaire (GHQ-30) predict all cause and cause-specific mortality. Methods Data on 2547 men and women from two cohorts, aged approximately 39 and 55 years, from the West of Scotland Twenty-07 Study who were followed up for mortality over an average of 18.9 (SD 5.0) years. Scores were calculated for HADS depression (HADS-D), HADS Anxiety (HADS-A) and GHQ-30. Cox Proportional Hazards Models were used to determine how each CMD measure predicted mortality. Results After adjusting for serious physical illness, smoking, social class, alcohol, obesity, pulse rate and living alone, HRs (95% CI) per SD increase in score for all-cause mortality were: 1.15 (1.07 to 1.25) for HADSD; 1.13 (1.04 to 1.23) for GHQ-30 and 1.05 (0.96 to 1.14) for HADS-A. After the same adjustments, cardiovascular disease mortality was also related to HADS-D (HR 1.24 (1.07 to 1.43)), to GHQ-30 (HR 1.24 (1.11 to 1.40)) and to HADS-A (HR 1.15 (1.01 to 1.32)); respiratory mortality to GHQ-30 (HR 1.33 (1.13 to 1.55)) and mortality from other causes, excluding injuries, to HADS-D (HR 1.28 (1.05 to 1.55)). Conclusions There were associations between CMD and both all-cause and cause-specific mortality which were broadly similar for GHQ-30 and HADS-D and were still present after adjustment for important confounders and mediators

DNA methylation of blood cells is associated with prevalent type 2 diabetes in a meta-analysis of four European cohorts

Background: Type 2 diabetes (T2D) is a heterogeneous disease with well-known genetic and environmental risk factors contributing to its prevalence. Epigenetic mechanisms related to changes in DNA methylation (DNAm), may also contribute to T2D risk, but larger studies are required to discover novel markers, and to confirm existing ones. Results: We performed a large meta-analysis of individual epigenome-wide association studies (EWAS) of prevalent T2D conducted in four European studies using peripheral blood DNAm. Analysis of differentially methylated regions (DMR) was also undertaken, based on the meta-analysis results. We found three novel CpGs associated with prevalent T2D in Europeans at cg00144180 (HDAC4), cg16765088 (near SYNM) and cg24704287 (near MIR23A) and confirmed three CpGs previously identified (mapping to TXNIP, ABCG1 and CPT1A). We also identified 77 T2D associated DMRs, most of them hypomethylated in T2D cases versus controls. In adjusted regressions among diabetic-free participants in ALSPAC, we found that all six CpGs identified in the meta-EWAS were associated with white cell-types. We estimated that these six CpGs captured 11% of the variation in T2D, which was similar to the variation explained by the model including only the common risk factors of BMI, sex, age and smoking (R2 = 10.6%). Conclusions: This study identifies novel loci associated with T2D in Europeans. We also demonstrate associations of the same loci with other traits. Future studies should investigate if our findings are generalizable in non-European populations, and potential roles of these epigenetic markers in T2D etiology or in determining long term consequences of T2D