Compounding vulnerabilities: Syndemics and the social determinants of disease in the past

Objective: This article explores the theory and utility of a syndemic approach for the study of disease in the past. Syndemic principles are examined alongside other theoretical developments within bioarchaeology. Two case studies are provided to illustrate the efficacy of this approach: Tuberculosis and vitamin D deficiency in 18th and 19th century England, and malaria and helminth infections in Early Medieval England. Materials: Public health studies of present syndemics, in addition to published bioarchaeological, clinical and social information relating to the chosen case studies. Methods: The data from these two historical examples are revisited within a syndemic framework to draw deeper conclusions about disease clustering and heterogeneity in the past. Results: A syndemic framework can be applied to past contexts using clinical studies of diseases in a modern context and relevant paleopathological, archaeological, and historical data. Conclusions: This approach provides a means for providing a deeper, contextualised understanding ancient diseases, and integrates well with extant theoretical tools in bioarchaeology Significance: Syndemics provides scholars a deep-time perspective on diseases that still impact modern populations. Limitations: Many of the variables essential for a truly syndemic approach cannot be obtained from current archaeological, bioarchaeological, or historical methods. Suggestions for further research: More detailed and in-depth analysis of specific disease clusters within the past and the present, which draws on a comprehensive analysis of the social determinants of health

The Children of the Reformation: Childhood Palaeoepidemiology in Britain, ad 1000–1700

CHILDHOOD IS A TIME of rapid biological growth and development, and a stage of the life course during which bodies are particularly sensitive to social and environmental stressors. As a consequence, events which may impact upon a child’s care and treatment can become physically embodied within their bones and teeth. The skeletal remains of children have been neglected within archaeological discourse until recently, but they are, in fact, a particularly important demographic for understanding the impact of social processes on past population health. This research examines the prevalence of skeletal disease in children (≤16 years) in Britain (England, Wales and Scotland) between ad 1000 and 1700. Data for a total of 4,626 children from 95 sites were collated from published and unpublished skeletal reports and analysed for evidence of skeletal changes reflecting disease. A biocultural approach was adopted in which the evidence was interpreted in relation to ecological, social, economic and environmental conditions. It was observed that childhood levels of skeletal stress did increase significantly after 1540. It was noted that during the Reformation sociocultural and economic factors added to stressors in the ecology of the medieval child. The effects of the Reformation were found to be the greatest aggravator in the rise of morbidity prevalence over seven centuries. Differences in morbidity patterns between non-adult age categories indicated that a state of ‘childhood’ existed until at least eleven years of age, after which there appears to have been a gradual transition into adolescence and adulthood

Alloparenting Adolescents: Evaluating the Social and Biological Impacts of Leprosy on Young People in Saxo-Norman England (9th to 12th Centuries AD) through Cross-Disciplinary Models of Care

The majority of historical sources describe past attitudes towards people with leprosy as negative, focussing on ostracism and damnation, and this is thought to have impacted on the care that sufferers received. More recent historical and archaeological evidence challenges this longstanding perspective, portraying a very different view of care for those with this potentially debilitating and disfiguring disease (Roberts 2002; Rawcliffe 2006; Roberts 2013; Roberts 2018). This paper aims to explore the social and biological impacts of adolescents with leprosy in SaxoNorman England (9th – 12th centuries AD). The intersection of youth, chronic infection, aspects of care (inclusive of medical, surgical, and daily support), and cultural identity has only been tangentially explored in the past (e.g see Redfern and Gowland 2011; Roberts and Bernard 2015; Lewis 2017). Studies that integrate these entwined themes can, however, provide a more holistic view of societal responses to wider encultured disease identities. This study utilises multiple lines of evidence for medical care and social treatment to evaluate the validity of dominant historical narratives about leprosy, i.e. that people in the past with leprosy were not cared for or treated well. In order to achieve this, the notion of past requirements of care and treatment through an alloparental model will be introduced. This is followed by a review of the existing historiographical evidence for medical care for young people in the medieval period to better understand systems of care provision and parental reactions to their sick children at this time. Discussions of leprosy in young people in the present and past will help contribute to longitudinal views of the biological impacts of leprosy and help the necessity for care in relation to certain pathological responses (i.e. the manifestation of lepromatous leprosy). To apply this framework to the past, palaeopathological and archaeological evidence from adolescent individuals excavated from the North Cemetery of St. Mary Magdalen leprosy hospital will be analysed. The presence of both leprosy and alloparental care for adolescents in the Saxo-Norman transition at this hospital is demonstrated. Finally, the construction of a theoretical model of required clinical care and provisions, such as the Index of Care framework, helps interpret the evidence for care in alloparental institutions such as leprosaria. The treatment of people with leprosy in the medieval period is often cited as a justification for the continuing stigma and community expulsion of family members with leprosy in some parts of the world (World Health Organization 2015). Therefore, it is worth examining the social milieu of this disease in which young people with leprosy in the past lived, and the models of care and treatment that may be interpreted from these data in order to dispel this longstanding stigma

Sex determination of human remains from peptides in tooth enamel

The assignment of biological sex to archaeological human skeletons is a fundamental requirement for the reconstruction of the human past. It is conventionally and routinely performed on adults using metric analysis and morphological traits arising from postpubertal sexual dimorphism. A maximum accuracy of ∼95% is possible if both the cranium and os coxae are present and intact, but this is seldom achievable for all skeletons. Furthermore, for infants and juveniles, there are no reliable morphological methods for sex determination without resorting to DNA analysis, which requires good DNA survival and is time-consuming. Consequently, sex determination of juvenile remains is rarely undertaken, and a dependable and expedient method that can correctly assign biological sex to human remains of any age is highly desirable. Here we present a method for sex determination of human remains by means of a minimally destructive surface acid etching of tooth enamel and subsequent identification of sex chromosome-linked isoforms of amelogenin, an enamel-forming protein, by nanoflow liquid chromatography mass spectrometry. Tooth enamel is the hardest tissue in the human body and survives burial exceptionally well, even when the rest of the skeleton or DNA in the organic fraction has decayed. Our method can reliably determine the biological sex of humans of any age using a body tissue that is difficult to cross-contaminate and is most likely to survive. The application of this method will make sex determination of adults and, for the first time, juveniles a reliable and routine activity in future bioarcheological and medico-legal science contexts

The effect of isocapnic hyperoxia on neurophysiology as measured with MRI and MEG

The physiological effect of hyperoxia has been poorly characterised, with studies reporting conflicting results on the role of hyperoxia as a vasoconstrictor. It is not clear whether hyperoxia is the primary contributor to vasoconstriction or whether induced changes in CO2 that commonly accompany hyperoxia are a factor. As calibrated BOLD fMRI based on hyperoxia becomes more widely used, it is essential to understand the effects of oxygen on resting cerebral physiology. This study used a RespirActTM system to deliver a repeatable isocapnic hyperoxia stimulus to investigate the independent effect of O2 on cerebral physiology, removing any potential confounds related to altered CO2. T1-independent Phase Contrast MRI was used to demonstrate that isocapnic hyperoxia has no significant effect on carotid blood flow (normoxia 201 ± 11 ml/min, -0.3 ± 0.8 % change during hyperoxia, p = 0.8), whilst Look Locker ASL was used to demonstrate that there is no significant change in arterial cerebral blood volume (normoxia 1.3 ± 0.4 %, -0.5 ± 5 % change during hyperoxia). These are in contrast to significant changes in blood flow observed for hypercapnia (6.8 ± 1.5 %/mmHg CO2). In addition, magnetoencephalography provided a method to monitor the effect of isocapnic hyperoxia on neuronal oscillatory power. In response to hyperoxia, a significant focal decrease in oscillatory power was observed across the alpha, beta and low gamma bands in the occipital lobe, compared to a more global significant decrease on hypercapnia. This work suggests that isocapnic hyperoxia provides a more reliable stimulus than hypercapnia for calibrated BOLD, and that previous reports of vasoconstriction during hyperoxia probably reflect the effects of hyperoxia-induced changes in CO2. However, hyperoxia does induce changes in oscillatory power consistent with an increase in vigilance, but these changes are smaller than those observed under hypercapnia. The effect of this change in neural activity on calibrated BOLD using hyperoxia or combined hyperoxia and hypercapnia needs further investigation

Towards a best practice for the use of active non-contact surface scanning to record human skeletal remains from archaeological contexts

Active surface scanners emit light or a laser stripe to record the exterior surface of an object or landscape, providing results in three dimensions. The use of active surface scanners to record anthropological and archaeological contexts has increased within the last few years, creating a number of sub-contexts within these disciplines, and allowing a further development of certain applications, such as quantitative analysis, the use of replicas in education and museums, and the creation of digital databases archived in institutions. However with guidance, this paper aims to assess the advantages and disadvantages of active surface scanning and the potential for research with regards to the recording and analysis of human skeletal remains. The key advantages and uses identified include: quantitative digitisation, geometric morphometric studies, conservation, preservation, documentation, and reconstruction. However, surface scanning also has some limitations, including: cost, technological expertise, the need for a power source, computing requirements, and data size. Overall, the application of active surface scanning technology to archaeological skeletal remains will provide a vital digital archive that will serve to preserve the integrity of this fragile and finite resource for future generations. This is particularly important within the current developer-funded environment in which many skeletal collections, including those yielding unique or unusual pathological or morphological features, are re-buried, with only very limited time for analysis

Global intravascular and local hyperoxia contrast phase-based blood oxygenation measurements

AbstractThe measurement of venous cerebral blood oxygenation (Yv) has potential applications in the study of patient groups where oxygen extraction and/or metabolism are compromised. It is also useful for fMRI studies to assess the stimulus-induced changes in Yv, particularly since basal Yv partially accounts for inter-subject variation in the haemodynamic response to a stimulus. A range of MRI-based methods of measuring Yv have been developed recently. Here, we use a method based on the change in phase in the MR image arising from the field perturbation caused by deoxygenated haemoglobin in veins. We build on the existing phase based approach (Method I), where Yv is measured in a large vein (such as the superior sagittal sinus) based on the field shift inside the vein with assumptions as to the vein's shape and orientation. We demonstrate two novel modifications which address limitations of this method. The first modification (Method II), maps the actual form of the vein, rather than assume a given shape and orientation. The second modification (Method III) uses the intra and perivascular phase change in response to a known change in Yv on hyperoxia to measure normoxic Yv in smaller veins. Method III can be applied to veins whose shape, size and orientation are not accurately known, thus allowing more localised measures of venous oxygenation. Results demonstrate that the use of an overly fine spatial filter caused an overestimation in Yv for Method I, whilst the measurement of Yv using Method II was less sensitive to this bias, giving Yv=0.62±0.03. Method III was applied to mapping of Yv in local veins across the brain, yielding a distribution of values with a mode of Yv=0.661±0.008

Calibrated BOLD using direct measurement of changes in venous oxygenation

Calibration of the BOLD signal is potentially of great value in providing a closer measure of the underlying changes in brain function related to neuronal activity than the BOLD signal alone, but current approaches rely on an assumed relationship between cerebral blood volume (CBV) and cerebral blood flow (CBF). This is poorly characterised in humans and does not reflect the predominantly venous nature of BOLD contrast, whilst this relationship may vary across brain regions and depend on the structure of the local vascular bed. This work demonstrates a new approach to BOLD calibration which does not require an assumption about the relationship between cerebral blood volume and cerebral blood flow. This method involves repeating the same stimulus both at normoxia and hyperoxia, using hyperoxic BOLD contrast to estimate the relative changes in venous blood oxygenation and venous CBV. To do this the effect of hyperoxia on venous blood oxygenation has to be calculated, which requires an estimate of basal oxygen extraction fraction, and this can be estimated from the phase as an alternative to using a literature estimate. Additional measurement of the relative change in CBF, combined with the blood oxygenation change can be used to calculate the relative change in CMRO2 due to the stimulus. CMRO2 changes of 18 ± 8% in response to a motor task were measured without requiring the assumption of a CBV/CBF coupling relationship, and are in agreement with previous approaches

Delayed gastric emptying and reduced postprandial small bowel water content of equicaloric whole meal bread versus rice meals in healthy subjects: novel MRI insights

BACKGROUND/OBJECTIVES: Postprandial bloating is a common symptom in patients with functional gastrointestinal (GI) diseases. Whole meal bread (WMB) often aggravates such symptoms though the mechanisms are unclear. We used magnetic resonance imaging (MRI) to monitor the intragastric fate of a WMB meal (11% bran) compared to a rice pudding (RP) meal. SUBJECTS/METHODS: 12 healthy volunteers completed this randomised crossover study. They fasted overnight and after an initial MRI scan consumed a glass of orange juice with a 2267 kJ WMB or an equicaloric RP meal. Subjects underwent serial MRI scans every 45 min up to 270 min to assess gastric volumes and small bowel water content and completed a GI symptom questionnaire. RESULTS: The MRI intragastric appearance of the two meals was markedly different. The WMB meal formed a homogeneous dark bolus with brighter liquid signal surrounding it. The RP meal separated into an upper, liquid layer and a lower particulate layer allowing more rapid emptying of the liquid compared to solid phase (sieving). The WMB meal had longer gastric half emptying times (132±8 min) compared to the RP meal (104±7 min), P<0.008. The WMB meal was associated with markedly reduced MRI-visible small bowel free mobile water content compared to the RP meal, P<0.0001. CONCLUSIONS: WMB bread forms a homogeneous bolus in the stomach which inhibits gastric sieving and hence empties slower than the equicaloric rice meal. These properties may explain why wheat causes postprandial bloating and could be exploited to design foods which prolong satiation