Photosynthetic pigments in sediments: development of applications in archaeology and compound-specific radiocarbon analysis

Photosynthetic pigments derived from oxygenic aquatic photoautotrophs are biosynthesised from dissolved carbon dioxide that reflects atmospheric concentrations of radiocarbon (14C). Sedimentary pigment signatures are not influenced by a terrestrial signal as terrestrial photosynthetic pigments are overwhelmingly destroyed by photo-oxidation. These properties have been exploited by this study to reveal the presence of archaeological water features and to radiocarbon date the timing of a geochemically significant event. A new approach for identifying archaeological structures suggested to represent former aquatic features has been developed. HPLC and LC-MSn analysis of sediment extracts from several suspected water features revealed the presence of photosynthetic pigment derivatives, thus providing evidence of the occurrence of photoautotrophic and heterotrophic aquatic organisms at the time the sediment was deposited. Chlorophyll derivatives diagnostic of heterotrophic communities and bacteriochlorophyll derivatives which provide information on photic zone anoxia and eutrophication have been detected in some sites. Thus, the detection of photosynthetic pigments in archaeological sediments provides a geochemical method for investigating the existence and evolution of water features in past landscapes. Photosynthetic pigments are ideal candidates for compound specific radiocarbon analysis (CSRA) as they have known primary sources of carbon. Sediments from Kirisjes Pond Antarctica, which have been previously radiocarbon dated using bulk organic material, were extracted and individual pigments isolated and purified by a preparative HPLC system that had been validated with test samples. The younger CSRA results obtained from each layer were more credible than bulk measurements due to the age sequence determined within the section examined, which led to differences in age of up to ca. 1500 years between measurements. CSRA of isolates was used to constrain the timing of a marine incursion to between 7736 and 4688 years before present. Comparison of 14C dates from algal and bacterial pigments suggest a reservoir effect of between ca. 5500 to 6000 years. Radiocarbon measurements of standards showed that no isotopic fractionation had occurred during preparative HPLC

Revisiting the equity debate in COVID-19 : ICU is no panacea

Copyright information No commercial re-use. See rights and permissions. Published by BMJ. This article is made freely available for use in accordance with BMJ's website terms and conditions for the duration of the covid-19 pandemic or until otherwise determined by BMJ. You may use, download and print the article for any lawful, non-commercial purpose (including text and data mining) provided that all copyright notices and trade marks are retained. https://bmj.com/coronavirus/usagePeer reviewedPostprin

Quality and safety of genetic testing in Australia and New Zealand: a review of the current regulatory framework

This paper provides an overview of the regulation of quality assurance for genetic testing in Australia and New Zealand and outlines the steps currently being taken to critically appraise and improve the regulatory framework in each country. It aims to contextualize this framework within the broader context of quality and patient safety concerns; and to draw together the concerns and recommendations of the various organizations that have been working to improve quality assurance in this area

The gastric acid pocket is attenuated in H. pylori infected subjects

Objective Gastric acid secretory capacity in different anatomical regions, including the postprandial acid pocket, was assessed in Helicobacter pylori positive and negative volunteers in a Western population. Design We studied 31 H. pylori positive and 28 H. pylori negative volunteers, matched for age, gender and body mass index. Jumbo biopsies were taken at 11 predetermined locations from the gastro-oesophageal junction and stomach. Combined high-resolution pH metry (12 sensors) and manometry (36 sensors) was performed for 20 min fasted and 90 min postprandially. The squamocolumnar junction was marked with radio-opaque clips and visualised radiologically. Biopsies were scored for inflammation and density of parietal, chief and G cells immunohistochemically. Results Under fasting conditions, the H. pylori positives had less intragastric acidity compared with negatives at all sensors >1.1 cm distal to the peak lower oesophageal sphincter (LES) pressure (p<0.01). Postprandially, intragastric acidity was less in H. pylori positives at sensors 2.2, 3.3 and 4.4 cm distal to the peak LES pressure (p<0.05), but there were no significant differences in more distal sensors. The postprandial acid pocket was thus attenuated in H. pylori positives. The H. pylori positives had a lower density of parietal and chief cells compared with H. pylori negatives in 10 of the 11 gastric locations (p<0.05). 17/31 of the H. pylori positives were CagA-seropositive and showed a more marked reduction in intragastric acidity and increased mucosal inflammation. Conclusions In population volunteers, H. pylori positives have reduced intragastric acidity which most markedly affects the postprandial acid pocket

Neurological impairment in nephropathic cystinosis: motor coordination deficits

Nephropathic cystinosis is a rare genetic metabolic disorder that results in accumulation of the amino acid cystine in lysosomes due to lack of a cystine-specific transporter protein. Cystine accumulates in cells throughout the body and causes progressive damage to multiple organs, including the brain. Neuromotor deficits have been qualitatively described in individuals with cystinosis. This study quantitatively examined fine-motor coordination in individuals with cystinosis. Brain magnetic resonance imaging (MRI) scans were also performed to determine whether structural changes were associated with motor deficits. Participants were 52 children and adolescents with infantile nephropathic cystinosis and 49 controls, ages 2–17 years, divided into preacademic and school-age groups. Results indicated that both the preacademic and school-age cystinosis groups performed significantly more poorly than their matched control groups on the Motor Coordination Test. Further, the level of performance was not significantly different between the preacademic and school-age groups. There were no significant differences in motor coordination scores based on MRI findings. This is the first study to document a persistent, nonprogressive, fine-motor coordination deficit in children and adolescents with cystinosis. The fact that these difficulties are present in the preschool years lends further support to the theory that cystinosis adversely affects neurological functioning early in development. The absence of a relationship between brain structural changes and motor function suggests that an alternative cause for motor dysfunction must be at work in this disorder

Digital contact tracing and exposure notification: ethical guidance for trustworthy pandemic management

10.1007/s10676-020-09566-8Ethics and Information Technology233285-29

Differences in responses of platelets to fluid shear stress in patients with peripheral artery disease (PAD) and coronary artery disease (CAD).

Information on differences in platelet function between patients with peripheral arterial disease (PAD) and patients with coronary artery disease (CAD) is limited. We sought to examine the differences in the platelets response to shear stress in patients with PAD compared to those with CAD. Men with symptomatic PAD (ankle brachial index [ABI] \u3c 0.9; n = 29) were compared with similarly aged men with CAD (post coronary artery bypass grafting; n = 40) but without PAD. All participants were on aspirin, and none were on clopidogrel. We measured changes in shear-induced platelet aggregation (SIPA) and shear-induced P-selectin expression (SIPE) under fluid shear rates of 5000 and 10,000 s(-1)which are typically found in arterioles and stenosed arteries, respectively. Aggregation was also induced by a combined stimulation of collagen, fluid shear stress, and adenosine diphosphate (ADP) or epinephrine using a platelet function analyzer (PFA-100) as well as optical aggregometry (arachidonic acid, collagen and epinephrine). Analyses of covariance adjusted for age, aspirin dose, and statin use were used to estimate differences between the groups. Values of SIPA at fluid shear rates of 5000 and 10,000 s(-1) were significantly higher in the PAD group, while there were no differences between the PAD and CAD groups in SIPE at both fluid shear rates. However, baseline shear-induced P-selectin expression was higher in patients with PAD than CAD (mean fluorescence intensity [MFI] = 2.93 +/- 1.37 vs.1.94 +/- 0.67; p = 0.01), while the percentage increases in SIPA and SIPE at fluid shear rates of 5000 and 10,000 s(-1) were significantly higher in patients with CAD when compared to PAD (p \u3c 0.001 for all comparisons). Although there were several similarities in platelet function between men with PAD and men with CAD, significant differences in platelet responses to shear stress were observed in men with PAD when compared to those with CAD. Although the mechanism for these observed differences are not clear, we hypothesize that in vivo platelet activation in PAD patients may contribute to the differences and will need to be further investigated

Equity in vaccine trials for higher weight people? A rapid review of weight-related inclusion and exclusion criteria for COVID-19 clinical trials

Higher weight status, defined as body mass index (BMI) ≥ 30 kg/m2, is frequently described as a risk factor for severity and susceptibility to severe acute respiratory syndrome coron-avirus 2 (SARS-CoV-2) disease (known as COVID-19). Therefore, study groups in COVID-19 vaccine trials should be representative of the weight spectrum across the global population. Appropriate subgroup analysis should be conducted to ensure equitable vaccine outcomes for higher weight people. In this study, inclusion and exclusion criteria of registered clinical trial protocols were reviewed to determine the proportion of trials including higher weight people, and the proportion of trials conducting subgroup analyses of efficacy by BMI. Eligibility criteria of 249 trial protocols (phase I, II, III and IV) were analysed; 51 protocols (20.5%) specified inclusion of BMI > 30, 73 (29.3%) specified exclusion of BMI > 30, and 125 (50.2%) did not specify whether BMI was an inclusion or exclusion criterion, or if BMI was included in any ‘health’ screenings or physical examinations during recruitment. Of the 58 protocols for trials in phase III and IV, only 2 (3.4%) indicated an intention to report subgroup analysis of vaccine efficacy by weight status. Higher weight people appear to be significantly under-represented in the majority of vaccine trials. This may result in reduced efficacy and acceptance of COVID-19 vaccines for higher weight people and exacerbation of health inequities within this population group. Explicit inclusion of higher weight people in COVID-19 vaccine trials is required to reduce health inequities

Disability Rights as a Necessary Framework for Crisis Standards of Care and the Future of Health Care

In this essay, we suggest practical ways to shift the framing of crisis standards of care toward disability justice. We elaborate on the vision statement provided in the 2010 Institute of Medicine (National Academy of Medicine) “Summary of Guidance for Establishing Crisis Standards of Care for Use in Disaster Situations,” which emphasizes fairness; equitable processes; community and provider engagement, education, and communication; and the rule of law. We argue that interpreting these elements through disability justice entails a commitment to both distributive and recognitive justice. The disability rights movement\u27s demand “Nothing about us, without us” requires substantive inclusion of disabled people in decision-making related to their interests, including in crisis planning before, during, and after a pandemic like Covid-19