Human brains preserve in diverse environments for at least 12 000 years

The brain is thought to be among the first human organs to decompose after death. The discovery of brains preserved in the archaeological record is therefore regarded as unusual. Although mechanisms such as dehydration, freezing, saponification, and tanning are known to allow for the preservation of the brain on short time scales in association with other soft tissues (≲4000 years), discoveries of older brains, especially in the absence of other soft tissues, are rare. Here, we collated an archive of more than 4400 human brains preserved in the archaeological record across approximately 12 000 years, more than 1300 of which constitute the only soft tissue preserved amongst otherwise skeletonized remains. We found that brains of this type persist on time scales exceeding those preserved by other means, which suggests an unknown mechanism may be responsible for preservation particular to the central nervous system. The untapped archive of preserved ancient brains represents an opportunity for bioarchaeological studies of human evolution, health and disease.

Fossilisation processes and our reading of animal antiquity

Estimates for animal antiquity exhibit a significant disconnect between those from molecular clocks, which indicate crown animals evolved ∼800 million years ago (Ma), and those from the fossil record, which extends only ∼574 Ma. Taphonomy is often held culpable: early animals were too small/soft/fragile to fossilise, or the circumstances that preserve them were uncommon in the early Neoproterozoic. We assess this idea by comparing Neoproterozoic fossilisation processes with those of the Cambrian and its abundant animal fossils. Cambrian Burgess Shale-type (BST) preservation captures animals in mudstones showing a narrow range of mineralogies; yet, fossiliferous Neoproterozoic mudstones rarely share the same mineralogy. Animal fossils are absent where BST preservation occurs in deposits ≥789 Ma, suggesting a soft maximum constraint on animal antiquity.

The role of clay minerals in the preservation of Precambrian organic-walled microfossils

Precambrian organic-walled microfossils (OWMs) are primarily preserved in mudstones and shales that are low in total organic carbon (TOC). Recent work suggests that high TOC may hinder OWM preservation, perhaps because it interferes with chemical interactions involving certain clay minerals that inhibit the decay of microorganisms. To test if clay mineralogy controls OWM preservation, and if TOC moderates the effect of clay minerals, we compared OWM preservational quality (measured by pitting on fossil surfaces and the deterioration of wall margins) to TOC, total clay, and specific clay mineral concentrations in 78 shale samples from 11 lithologic units ranging in age from ca. 1650 to 650 million years ago. We found that the probability of finding well-preserved microfossils positively correlates with total clay concentrations and confirmed that it negatively correlates with TOC concentrations. However, we found no evidence that TOC influences the effect of clay mineral concentrations on OWM preservation, supporting an independent role of both factors on preservation. Within the total clay fraction, well-preserved microfossils are more likely to occur in shales with high illite concentrations and low berthierine/chamosite concentrations; however, the magnitude of their effect on preservation is small. Therefore, there is little evidence that bulk clay chemistry is important in OWM preservation. Instead, we propose that OWM preservation is largely regulated by physical properties that isolate organic remains from microbial degradation such as food scarcity (low TOC) and low sediment permeability (high total clay content): low TOC increases the diffusive distances between potential carbon sources and heterotrophic microbes (or their degradative enzymes), while high clay concentrations reduce sediment pore space, thereby limiting the diffusion of oxidants and degradative enzymes to the sites of decay.

A7 OPPORTUNISTIC PATHOGEN MODULATION OF GLUTEN-REACTIVE CD4+ T CELL ACTIVATION BY DQ2-EXPRESSING ORGANOID MONOLAYERS

Background

Bacteria have recently emerged as additional modulators of inflammation in CeD. We have shown that the elastase-like producing opportunistic pathogen, Pseudomonas (P) aeruginosa, partially metabolizes gluten into peptides that translocate the mucosal barrier and retain their immunogenicity. We previously demonstrated that organoid monolayers derived from DR3-DQ2 mice carrying the CeD risk gene HLA-DQ2 express MHC class II (HLA-DQ2) and co-stimulatory molecules under induced inflammatory conditions, priming the monolayers for gluten antigen presentation. Here we investigate the activation of human (h)CD4⁺ T cell co-cultured with DQ2 monolayers stimulated with gluten pre-digested, or not, by bacterial elastase.

Purpose

To investigate whether organoid monolayers expressing DQ2 activate T cell differentially in the presence of gluten metabolized by elastase-like producing Pseudomonas aeruginosa.

Method

Organoid monolayers were derived from the duodenum and proximal jejunum of gluten-sensitized DR3-DQ2 mice, following the gluten sensitization protocol previously described¹. Monolayers were then stimulated with IFN-γ for 24h to induce MHC-II and co-stimulatory molecules expression. Splenic T-cell expressing hCD4 from gluten-sensitized DR3-DQ2-hCD4 mice were then co-cultured with monolayers in the presence of deamidated pepsin-trypsin-digested (DAPT)-gluten or Pseudomonas aeruginosa PA14 (WT)-digested DAPT-gluten. As a control, DAPT-gluten was incubated with a P. aeruginosa lasB mutant strain that lacks elastase-like activity (lasB^△/△). Co-cultures stimulated with DAPT-gluten alone or WT-media were used as additional controls.

Result(s)

Increased hCD4⁺ T-cell proliferation was observed in co-cultures stimulated with WT-digested gluten compared with lasB^△/△-digested gluten (p<0.0001), gluten alone (p=0.0002) or WT-media (p<0.0001). hCD4⁺ T cell co-cultured with organoid monolayers stimulated with WT-digested gluten, had an activated phenotype with increased expression of CD69, CD44 and CD25 versus those stimulated with gluten, lasB^△/△-digested gluten, or WT-media. Increased levels of pro-inflammatory and T helper type 1 (Th1)-associated cytokines were detected in the supernatant of the co-cultures stimulated with WT-digested gluten, including IL-2, IFN-γ, IL-6, TNF-α, IL-1α, IL-β, and IL-15.

Conclusion(s)

Using a novel HLA-DQ2-expressing organoid monolayer, we demonstrate elastase-like producing P. aeruginosa, enhanced activation and proliferation of hCD4⁺ T cell through gluten metabolism. This in vitro model constitutes a relevant tool for studying microbial triggers and drivers of intestinal epithelial dysfunction in CeD.

1. Galipeau, H. J. et al. 1. Galipeau, H. J. et al. Sensitization to Gliadin Induces Moderate Enteropathy and Insulitis in Nonobese Diabetic-DQ8 Mice. J. Immunol.187, 4338–4346 (2011).

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Disclosure of Interest

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Whole blood interleukin-2 release test to detect and characterize rare circulating gluten-specific T cell responses in coeliac disease

Whole blood cytokine release assays (CRA) assessing cellular immunity to gluten could simplify the diagnosis and monitoring of coeliac disease (CD). We aimed to determine the effectiveness of electrochemiluminescence CRA to detect responses to immunodominant gliadin peptides. HLA-DQ2·5⁺ CD adults (cohort 1, n = 6; cohort 2, n = 12) and unaffected controls (cohort 3, n = 9) were enrolled. Cohort 1 had 3-day gluten challenge (GC). Blood was collected at baseline, and for cohort 1 also at 3 h, 6 h and 6 days after commencing 3-day GC. Gliadin peptide-stimulated proliferation, interferon (IFN)-γ enzyme-linked immunospot (ELISPOT) and 14- and 3-plex electrochemiluminescence CRA were performed. Poisson distribution analysis was used to estimate responding cell frequencies. In cohort 1, interleukin (IL)-2 dominated the gliadin peptide-stimulated cytokine release profile in whole blood. GC caused systemic IL-2 release acutely and increased gliadin peptide-stimulated IFN-γ ELISPOT and whole blood CRA responses. Whole blood CRA after GC was dominated by IL-2, but also included IFN-γ, C-X-C motif chemokine ligand 10/IFN-γ-induced protein 10 (CXCL10/IP-10), CXCL9/monokine induced by IFN-γ (MIG), IL-10, chemokine (C-C motif) ligand 3/macrophage inflammatory protein 1-alpha (CCL3/MIP-1α), TNF-α and IL-8/CXCL8. In cohorts 2 and 3, gliadin peptide-stimulated whole blood IL-2 release was 100% specific and 92% sensitive for CD patients on a gluten-free diet; the estimated frequency of cells in CD blood secreting IL-2 to α-gliadin peptide was 0·5 to 11 per ml. Whole blood IL-2 release successfully mapped human leucocyte antigen (HLA)-DQ2·5-restricted epitopes in an α-gliadin peptide library using CD blood before and after GC. Whole blood IL-2 release assay using electrochemiluminescence is a sensitive test for rare gliadin-specific T cells in CD, and could aid in monitoring and diagnosis. Larger studies and validation with tetramer-based assays are warranted.

Aluminosilicate haloes preserve complex life approximately 800 million years ago

Mudstone-hosted microfossils are a major component of the Proterozoic fossil record, particularly dominating the record of early eukaryotic life. Early organisms possessed no biomineralized parts to resist decay and controls on their fossilization in mudstones are poorly understood. Consequently, the Proterozoic fossil record is compromised-we do not know whether changing temporal/spatial patterns of microfossil occurrences reflect evolution or the distribution of favourable fossilization conditions. We investigated fossilization within the approximately 1000 Ma Lakhanda Group (Russia) and the approximately 800 Ma Svanbergfjellet and Wynniatt formations (Svalbard and Arctic Canada). Vertical sections of microfossils and surrounding matrices were extracted from thin sections by focused ion beam milling. Elemental mapping and synchrotron-based infrared microspectroscopy revealed that microfossils are surrounded by haloes rich in aluminium, probably hosted in kaolinite. Kaolinite has been implicated in Cambrian Burgess Shale-type (BST) fossilization and is known to slow the growth of degraders. The Neoproterozoic mudstone microfossil record may be biased to tropical settings conducive to kaolinite formation. These deposits lack metazoan fossils even though they share fossilization conditions with younger BST deposits that are capable of preserving non-mineralizing metazoans. Thus metazoans, at least those typically preserved in BST deposits, were probably absent from sedimentary environments before approximately 800 Ma.

Serum cytokines elevated during gluten-mediated cytokine release in coeliac disease

Cytokines have been extensively studied in coeliac disease, but cytokine release related to exposure to gluten and associated symptoms has only recently been described. Prominent, early elevations in serum interleukin (IL)-2 after gluten support a central role for T cell activation in the clinical reactions to gluten in coeliac disease. The aim of this study was to establish a quantitative hierarchy of serum cytokines and their relation to symptoms in patients with coeliac disease during gluten-mediated cytokine release reactions. Sera were analyzed from coeliac disease patients on a gluten free-diet (n = 25) and from a parallel cohort of healthy volunteers (n = 25) who underwent an unmasked gluten challenge. Sera were collected at baseline and 2, 4 and 6 h after consuming 10 g vital wheat gluten flour; 187 cytokines were assessed. Confirmatory analyses were performed by high-sensitivity electrochemiluminescence immunoassay. Cytokine elevations were correlated with symptoms. Cytokine release following gluten challenge in coeliac disease patients included significant elevations of IL-2, chemokine (C-C motif) ligand 20 (CCL20), IL-6, chemokine (C-X-C motif) ligand (CXCL)9, CXCL8, interferon (IFN)-γ, IL-10, IL-22, IL-17A, tumour necrosis factor (TNF)-α, CCL2 and amphiregulin. IL-2 and IL-17A were earliest to rise. Peak levels of cytokines were generally at 4 h. IL-2 increased most (median 57-fold), then CCL20 (median 10-fold). Cytokine changes were strongly correlated with one another, and the most severely symptomatic patients had the highest elevations. Early elevations of IL-2, IL-17A, IL-22 and IFN-γ after gluten in patients with coeliac disease implicates rapidly activated T cells as their probable source. Cytokine release after gluten could aid in monitoring experimental treatments and support diagnosis.

Understanding Policy Diffusion in the U.S.: An Information-Theoretical Approach to Unveil Connectivity Structures in Slowly Evolving Complex Systems

Detecting and explaining the relationships among interacting components has long been a focal point of dynamical systems research. In this paper, we extend these types of data-driven analyses to the realm of public policy, whereby individual legislative entities interact to produce changes in their legal and political environments. We focus on the U.S. public health policy landscape, whose complexity determines our capacity as a society to effectively tackle pressing health issues. It has long been thought that some U.S. states innovate and enact new policies, while others mimic successful or competing states. However, the extent to which states learn from others, and the state characteristics that lead two states to influence one another, are not fully understood. Here, we propose a model-free, information-theoretical method to measure the existence and direction of influence of one state's policy or legal activity on others. Specifically, we tailor a popular notion of causality to handle the slow time-scale of policy adoption dynamics and unravel relationships among states from their recent law enactment histories. The method is validated using surrogate data generated from a new stochastic model of policy activity. Through the analysis of real data in alcohol, driving safety, and impaired driving policy, we provide evidence for the role of geography, political ideology, risk factors, and demographic and economic indicators on a state's tendency to learn from others when shaping its approach to public health regulation. Our method offers a new model-free approach to uncover interactions and establish cause-and-effect in slowly-evolving complex dynamical systems.

All the better to see you with: eyes and claws reveal the evolution of divergent ecological roles in giant pterygotid eurypterids

Pterygotid eurypterids have traditionally been interpreted as active, high-level, visual predators; however, recent studies of the visual system and cheliceral morphology of the pterygotid Acutiramus contradict this interpretation. Here, we report similar analyses of the pterygotids Erettopterus, Jaekelopterus and Pterygotus, and the pterygotid sister taxon Slimonia. Representative species of all these genera have more acute vision than A. cummingsi. The visual systems of Jaekelopterus rhenaniae and Pterygotus anglicus are comparable to that of modern predatory arthropods. All species of Jaekelopterus and Pterygotus have robust crushing chelicerae, morphologically distinct from the weaker slicing chelicerae of Acutiramus. Vision in Erettopterus osiliensis and Slimonia acuminata is more acute than in Acutiramus cummingsi, but not to the same degree as in modern active predators, and the morphology of the chelicerae in these genera suggests a grasping function. The pterygotids evolved with a shift in ecology from generalized feeder to specialized predator. Pterygotid eurypterids share a characteristic morphology but, although some were top predators, their ecology differs radically between genera.

The 'Tully monster' is a vertebrate

Problematic fossils, extinct taxa of enigmatic morphology that cannot be assigned to a known major group, were once a major issue in palaeontology. A long-favoured solution to the 'problem of the problematica', particularly the 'weird wonders' of the Cambrian Burgess Shale, was to consider them representatives of extinct phyla. A combination of new evidence and modern approaches to phylogenetic analysis has now resolved the affinities of most of these forms. Perhaps the most notable exception is Tullimonstrum gregarium, popularly known as the Tully monster, a large soft-bodied organism from the late Carboniferous Mazon Creek biota (approximately 309-307 million years ago) of Illinois, USA, which was designated the official state fossil of Illinois in 1989. Its phylogenetic position has remained uncertain and it has been compared with nemerteans, polychaetes, gastropods, conodonts, and the stem arthropod Opabinia. Here we review the morphology of Tullimonstrum based on an analysis of more than 1,200 specimens. We find that the anterior proboscis ends in a buccal apparatus containing teeth, the eyes project laterally on a long rigid bar, and the elongate segmented body bears a caudal fin with dorsal and ventral lobes. We describe new evidence for a notochord, cartilaginous arcualia, gill pouches, articulations within the proboscis, and multiple tooth rows adjacent to the mouth. This combination of characters, supported by phylogenetic analysis, identifies Tullimonstrum as a vertebrate, and places it on the stem lineage to lampreys (Petromyzontida). In addition to increasing the known morphological disparity of extinct lampreys, a chordate affinity for T. gregarium resolves the nature of a soft-bodied fossil which has been debated for more than 50 years.

What big eyes you have: the ecological role of giant pterygotid eurypterids

Eurypterids are a group of extinct chelicerates that ranged for over 200 Myr from the Ordovician to the Permian. Gigantism is common in the group; about 50% of families include taxa over 0.8 m in length. Among these were the pterygotids (Pterygotidae), which reached lengths of over 2 m and were the largest arthropods that ever lived. They have been interpreted as highly mobile visual predators on the basis of their large size, enlarged, robust chelicerae and forward-facing compound eyes. Here, we test this interpretation by reconstructing the visual capability of Acutiramus cummingsi (Pterygotidae) and comparing it with that of the smaller Eurypterus sp. (Eurypteridae), which lacked enlarged chelicerae, and other arthropods of similar geologic age. In A. cummingsi, there is no area of lenses differentiated to provide increased visual acuity, and the interommatidial angles (IOA) do not fall within the range of high-level modern arthropod predators. Our results show that the visual acuity of A. cummingsi is poor compared with that of co-occurring Eurypterus sp. The ecological role of pterygotids may have been as predators on thin-shelled and soft-bodied prey, perhaps in low-light conditions or at night.

A jump persistent turning walker to model zebrafish locomotion

Zebrafish are gaining momentum as a laboratory animal species for the investigation of several functional and dysfunctional biological processes. Mathematical models of zebrafish behaviour are expected to considerably aid in the design of hypothesis-driven studies by enabling preliminary in silico tests that can be used to infer possible experimental outcomes without the use of zebrafish. This study is motivated by observations of sudden, drastic changes in zebrafish locomotion in the form of large deviations in turn rate. We demonstrate that such deviations can be captured through a stochastic mean reverting jump diffusion model, a process that is commonly used in financial engineering to describe large changes in the price of an asset. The jump process-based model is validated on trajectory data of adult subjects swimming in a shallow circular tank obtained from an overhead camera. Through statistical comparison of the empirical distribution of the turn rate against theoretical predictions, we demonstrate the feasibility of describing zebrafish as a jump persistent turning walker. The critical role of the jump term is assessed through comparison with a simplified mean reversion diffusion model, which does not allow for describing the heavy-tailed distributions observed in the fish turn rate.

Ex-vivo whole blood secretion of interferon (IFN)-γ and IFN-γ-inducible protein-10 measured by enzyme-linked immunosorbent assay are as sensitive as IFN-γ enzyme-linked immunospot for the detection of gluten-reactive T cells in human leucocyte antigen (HLA)-DQ2·5(+) -associated coeliac disease

T cell cytokine release assays are used to diagnose infectious diseases, but not autoimmune or allergic disease. Coeliac disease (CD) is a common T cell-mediated disease diagnosed by the presence of gluten-dependent intestinal inflammation and serology. Many patients cannot be diagnosed with CD because they reduce dietary gluten before medical workup. Oral gluten challenge in CD patients treated with gluten-free diet (GFD) mobilizes gluten-reactive T cells measurable by interferon (IFN)-γ enzyme-linked immunospot (ELISPOT) or major histocompatibility complex (MHC) class II tetramers. Immunodominant peptides are quite consistent in the 90% of patients who possess HLA-DQ2·5. We aimed to develop whole blood assays to detect gluten-specific T cells. Blood was collected before and after gluten challenge from GFD donors confirmed to have CD (n = 27, all HLA-DQ2·5(+) ), GFD donors confirmed not to have CD (n = 6 HLA-DQ2·5(+) , 11 HLA-DQ2·5(-) ) and donors with CD not following GFD (n = 4, all HLA-DQ2·5(+) ). Plasma IFN-γ and IFN-γ inducible protein-10 (IP-10) were measured by enzyme-linked immunosorbent assay (ELISA) after whole blood incubation with peptides or gliadin, and correlated with IFN-γ ELISPOT. No T cell assay could distinguish between CD patients and controls prior to gluten challenge, but after gluten challenge the whole blood IFN-γ ELISA and the ELISPOT were both 85% sensitive and 100% specific for HLA-DQ2·5(+) CD patients; the whole blood IP-10 ELISA was 94% sensitive and 100% specific. We conclude that whole blood cytokine release assays are sensitive and specific for detection of gluten-reactive T cells in CD; further clinical studies addressing the utility of these tests in patients with an uncertain diagnosis of CD is warranted.

A scripted control system for autonomous hardware-timed experiments

We present the labscript suite, an open-source experiment control system for automating shot-based experiments and their analysis. Experiments are composed as Python code, which is used to produce low-level hardware instructions. They are queued up and executed on the hardware in real time, synchronized by a pseudoclock. Experiment parameters are manipulated graphically, and analysis routines are run as new data are acquired. With this system, we can easily automate exploration of parameter spaces, including closed-loop optimization.

A versatile high resolution objective for imaging quantum gases

We present a high resolution objective lens made entirely from catalog singlets that has a numerical aperture of 0.36. It corrects for aberrations introduced by a glass window and has a long working distance of 35 mm, making it suitable for imaging objects within a vacuum system. This offers simple high resolution imaging for many in the quantum gas community. The objective achieves a resolution of 1.3 μm at the design wavelength of 780 nm, and a diffraction-limited field of view of 360 μm when imaging through a 5 mm thick window. Images of a resolution target and a pinhole show quantitative agreement with the simulated lens performance. The objective is suitable for diffraction-limited monochromatic imaging on the D2 line of all the alkalis by changing only the aperture diameter, retaining numerical apertures above 0.32. The design corrects for window thicknesses of up to 15 mm if the singlet spacings are modified.

Dissecting the T-cell response to hordeins in coeliac disease can develop barley with reduced immunotoxicity

BACKGROUND

Wheat, rye and barley prolamins are toxic to patients with coeliac disease. Barley is diploid with pure inbred cultivars available, and is attractive for genetic approaches to detoxification.

AIM

To identify barley hordein fractions which activated the interferon-γ (IFN-γ) secreting peripheral blood T-cells from coeliac volunteers, and compare immunotoxicity of hordeins from experimental barley lines.

METHODS

To reactivate a T-cell response to hordein, volunteers underwent a 3-day oral barley challenge. Peripheral blood mononuclear cells (PBMC) were isolated from twenty-one HLA DQ2(+) patients with confirmed coeliac disease. IFN-γ ELISpot assays enumerated T-cells activated by purified prolamins and positive controls.

RESULTS

Hordein-specific T-cells were induced by oral barley challenge. All prolamin fractions were immunotoxic, but D- and C-hordeins were most active. Barley lines lacking B- and C-hordeins had a 5-fold reduced hordein-content, and immunotoxicity of hordein extracts were reduced 20-fold compared with wild-type barley.

CONCLUSIONS

In vivo oral barley challenge offers a convenient and rapid approach to test the immunotoxicity of small amounts of purified hordeins using fresh T-cells from patients in high throughput overnight assays. Barley lines that did not accumulate B- and C-hordeins were viable, yet had substantially reduced immunotoxicity. Creation of hordein-free barley may therefore be possible.

Coeliac disease: current approach and future prospects

Public anxiety over gluten has fuelled widespread demand for gluten-free food, yet coeliac disease remains significantly underdiagnosed and some confusion remains regarding optimal diagnostic practices. Small bowel histology is the gold standard for diagnosis. High-quality commercial enzyme-linked immunosorbent assays for transglutaminase immunoglobulin A and deamidated gliadin immunoglobulin A and G are sensitive tools for screening, but almost 10% of coeliac disease is seronegative and serological testing is unreliable in the very young, in people already following a gluten-reduced diet, and those using immunosuppressive medications. HLA DQA and DQB genotyping to show that alleles encoding HLA DQ2 and DQ8 are absent virtually excludes coeliac disease. Confirming histological remission reduces the risks of later complications, such as osteoporosis and cancer. Monitoring remission by serology is unreliable. Because gluten is an exogenous antigen and the small intestine is readily accessible, the immunopathogenesis of coeliac disease is better understood than other strongly major histocompatibility complex class II-associated diseases, such as type 1 diabetes mellitus. Therapeutic targets have been identified and drugs are under development to supplement or even replace gluten-free diet. With greater awareness and non-dietary therapeutics, diagnosis and treatment of coeliac disease will be increasingly prominent in medical practice.

Systematic review: The evidence base for long-term management of coeliac disease

BACKGROUND

While gluten-free diet is an effective treatment for coeliac disease, the need for and goals of long-term management of patients are poorly defined.

AIM

To review systematically the complications and associations of coeliac disease, to identify potential risk factors, to define ways of assessing risk factors and to provide a strategy for management.

METHODS

Review of medical literature from 1975.

RESULTS

There is an increasing list of potential complications and/or conditions associated with coeliac disease, in particular, autoimmune disease, malignancy and bone disease. Risk factors that may predict or influence long-term outcomes include genetic susceptibility, environmental factors predominantly gluten ingestion, persistent small intestinal inflammation/injury and nutritional deficiencies. Genotyping of patients is yet to have an established clinical role in long-term management. Assessment of adherence to the gluten-free diet largely relies upon skilled dietary history, but the ultimate test is duodenal histopathology, which is the only currently established means of assessing healing. Symptoms, serology or other non-invasive means are poor predictors of healing and the likelihood of complications.

CONCLUSION

Evidence (albeit limited) that adherence to a gluten-free diet and mucosal healing prevent and/or ameliorate complications indicates that a planned long-term strategy for follow-up is essential.

Antagonists and non-toxic variants of the dominant wheat gliadin T cell epitope in coeliac disease

BACKGROUND

Coeliac disease (CD) is due to an inappropriate T cell mediated response to specific gluten peptides. Measured by interferon gamma (IFN-gamma) ELISPOT, about half of the gliadin specific T cells induced with in vivo wheat gluten exposure in HLA-DQ2+ CD are specific for an alpha/beta-gliadin peptide (p57-73 QE65; QLQPFPQPELPYPQPQS) that includes two overlapping T cell epitopes (PFPQPELPY and PQPELPYPQ).

AIM

To define minimally substituted variants of p57-73 QE65 universally devoid of IFN-gamma stimulatory capacity but capable of antagonising IFN-gamma secretion from polyclonal T cells specific for p57-73 QE65.

METHODS

Peripheral blood mononuclear cells collected from 75 HLA-DQ2+ CD patients after in vivo gluten challenge were used in overnight ELISPOT assays to screen 218 single or double substituted variants of p57-73 QE65 for cytokine stimulatory and antagonist activity.

RESULTS

The region p60-71 (PFPQPELPYPQP) and especially p64-67 (PELP) was sensitive to substitution. Twelve substitutions in p64-67 stimulated no IFN-gamma ELISPOT response. Among 131 partial agonists identified, 45 produced statistically significant inhibition of IFN-gamma ELISPOT responses when cocultured in fivefold excess with p57-73 QE65 (n = 10). Four substituted variants of p57-73 QE65 were inactive by IFN-gamma ELISPOT but consistently antagonised IFN-gamma ELISPOT responses to p57-73 QE65, and also retained interleukin 10 stimulatory capacity similar to p57-73 QE65.

CONCLUSIONS

Altered peptide ligands of p57-73 QE65, identified using polyclonal T cells from multiple HLA-DQ2+ CD donors, have properties in vitro that suggest that a single substitution to certain alpha/beta-gliadins could abolish their capacity to stimulate IFN-gamma from CD4 T cells and also have anti-inflammatory or protective effects in HLA-DQ2+ CD.

T cells in peripheral blood after gluten challenge in coeliac disease

BACKGROUND

Current understanding of T cell epitopes in coeliac disease (CD) largely derives from intestinal T cell clones in vitro. T cell clones allow identification of gluten peptides that stimulate T cells but do not quantify their contribution to the overall gluten specific T cell response in individuals with CD when exposed to gluten in vivo.

AIMS

To determine the contribution of a putative dominant T cell epitope to the overall gliadin T cell response in HLA-DQ2 CD in vivo.

PATIENTS

HLA-DQ2+ individuals with CD and healthy controls.

METHODS

Subjects consumed 20 g of gluten daily for three days. Interferon gamma (IFN-gamma) ELISPOT was performed using peripheral blood mononuclear cells (PBMC) to enumerate and characterise peptide and gliadin specific T cells before and after gluten challenge.

RESULTS

In 50/59 CD subjects, irrespective of homo- or heterozygosity for HLA-DQ2, IFN-gamma ELISPOT responses for an optimal concentration of A-gliadin 57-73 Q-E65 were between 10 and 1500 per million PBMC, equivalent to a median 51% of the response for a "near optimal" concentration of deamidated gliadin. Whole deamidated gliadin and gliadin epitope specific T cells induced in peripheral blood expressed an intestinal homing integrin (alpha4beta7) and were HLA-DQ2 restricted. Peripheral blood T cells specific for A-gliadin 57-73 Q-E65 are rare in untreated CD but can be predictably induced two weeks after gluten exclusion.

CONCLUSION

In vivo gluten challenge is a simple safe method that allows relevant T cells to be analysed and quantified in peripheral blood by ELISPOT, and should permit comprehensive high throughput mapping of gluten T cell epitopes in large numbers of individuals with CD.

Actuarial and actual analysis of surgical results: empirical validation

This report validates the use of the Kaplan-Meier (actuarial) method of computing survival curves by comparing 12-year estimates published in 1978 with current assessments. It also contrasts cumulative incidence curves, referred to as "actual" analysis in the cardiac-related literature with Kaplan-Meier curves for thromboembolism and demonstrates that with the former estimate the percentage of events that will actually occur.

In vivo antigen challenge in celiac disease identifies a single transglutaminase-modified peptide as the dominant A-gliadin T-cell epitope

Celiac disease (CD) is an increasingly diagnosed enteropathy (prevalence, 1:200-1:300) that is induced by dietary exposure to wheat gliadins (as well as related proteins in rye and barley) and is strongly associated with HLA-DQ2 (alpha1*0501, beta1*0201), which is present in over 90% of CD patients. Because a variety of gliadin peptides have been identified as epitopes for gliadin-specific T-cell clones and as bioactive sequences in feeding studies and in ex vivo CD intestinal biopsy challenge, it has been unclear whether a 'dominant' T-cell epitope is associated with CD. Here, we used fresh peripheral blood lymphocytes from individual subjects undergoing short-term antigen challenge and tissue transglutaminase-treated, overlapping synthetic peptides spanning A-gliadin to demonstrate a transient, disease-specific, DQ2-restricted, CD4 T-cell response to a single dominant epitope. Optimal gamma interferon release in an ELISPOT assay was elicited by a 17-amino-acid peptide corresponding to the partially deamidated peptide of A-gliadin amino acids 57-73 (Q65E). Consistent with earlier reports indicating that host tissue transglutaminase modification of gliadin enhances gliadin-specific CD T-cell responses, tissue transglutaminase specifically deamidated Q65 in the peptide of A-gliadin amino acids 56-75. Discovery of this dominant epitope may allow development of antigen-specific immunotherapy for CD.

The STS National Database: current changes and challenges for the new millennium. Committee to Establish a National Database in Cardiothoracic Surgery, The Society of Thoracic Surgeons

BACKGROUND

The Society of Thoracic Surgeons (STS) established the National Database (NDB) for Cardiac Surgery in 1989. Since then it has grown to be the largest database of its kind in medicine. The NDB has been one of the pioneers in the analysis and reporting of risk-adjusted outcomes in cardiothoracic surgery.

METHODS AND RESULTS

This report explains the numerous changes in the NDB and its structure that have occurred over the past 2 years. It highlights the benefits of these changes, both to the individual member participants and to the STS overall. Additionally, the vision changes to the NDB and reporting structure are identified. The individuals who have participated in this effort since 1989 are acknowledged, and the STS owes an enormous debt of gratitude to each of them.

CONCLUSIONS

Because of their collective efforts, the goal to establish the STS NDB as a "gold standard" worldwide for process and outcomes analysis related to cardiothoracic surgery is becoming a reality.

The use of micro-dose aprotinin with continuous infusion in coronary artery bypass surgery

BACKGROUND

To evaluate the efficacy of aprotinin at a dose far less than standard.

METHODS

EXPERIMENTAL DESIGN

Retrospective, case-control study.

SETTING

community-based, teaching hospital

PATIENTS

one hundred one patients undergoing primary, non-emergent, coronary artery bypass during two, six-month periods were studied.

INTERVENTIONS

during the first period aprotinin was not administered, and these patients served as controls (n = 52). During the second period all patients received aprotinin via a micro-dose regimen (n = 49).

MEASURES

postoperative bleeding and blood product usage served as determinants of efficacy.

RESULTS

A significant difference existed in postoperative bleeding with the mean thoracic drain outputs being reduced in the aprotinin group both at 6 hours (p = 0.0003) and in total (p = 0.0004). This was further supported by significantly higher hematocrits (p = 0.03) on the first postoperative day in patients receiving aprotinin. Likewise, there was a significant reduction in total blood product exposures (p = 0.04) and platelet usage (p = 0.02) in the aprotinin group with a tendency towards decreased red cell usage. Further, when all patients with a hematocrit < or =30% prior to bypass were excluded, the significant reduction in total blood product exposures persisted (p = 0.04), and there was a significant reduction in red cell usage (p = 0.04) with a trend towards decreased platelet usage (p = 0.06) in the aprotinin group.

CONCLUSIONS

Micro-dose aprotinin significantly reduces postoperative bleeding and blood product usage in primary, non-emergent, CABG patients.

Inflammatory bowel disease

IBD results from the interaction of genetic and environmental factors (e.g., smoking). Clinical suspicion is the key to diagnosis, which then rests on colonoscopy, histopathological examination of multiple biopsy specimens, small bowel barium radiology and faecal examination. The primary goal of treatment is remission--histological in ulcerative colitis and symptomatic in Crohn's disease. Treating active disease and maintaining remission require different approaches. For active disease, short term corticosteroids are the mainstay of treatment, while immunosuppressive drugs are important in chronically active disease. For maintenance, mesalazine-delivering drugs and immunosuppressive agents are efficacious in both ulcerative colitis and Crohn's disease; patients with Crohn's disease should not smoke.

Time-related analysis of nonfatal heart valve complications: cumulative incidence (actual) versus Kaplan-Meier (actuarial)

BACKGROUND

The cumulative incidence of a postoperative event is the percentage of patients who experience the event by postoperative time T. Its complete determination requires all patients to be followed until T. In ongoing series, the Kaplan-Meier method is employed because not all patients have been observed until T. When applied to nonfatal events, however, the Kaplan-Meier estimates probabilities as if the patients who die before they sustain an event continue to be at risk thereafter. It thus estimates risk in the unrealistic situation where death does not occur.

METHODS AND RESULTS

Cumulative incidence can be estimated directly, to provide the probability of actually experiencing an event before death, that is, when death properly eliminates patients from further risk of the event. We compare cumulative incidence and Kaplan-Meier estimates in two series of mitral valve replacement patients: thromboembolism in a completed series of ball valves implanted in relatively young patients and valve explant in an ongoing series of porcine valves in older patients. Kaplan-Meier estimated a higher event percentage than the cumulative incidence, and the difference was greater in the older patients, who had a higher death rate.

CONCLUSIONS

Cumulative incidence, unlike Kaplan-Meier, provides estimates of the percentage of patients who will actually sustain an event. Cumulative incidence is more meaningful for individual patient counseling and more useful for estimating resource utilization in a managed population.

Beta blockade to prevent atrial dysrhythmias following coronary bypass surgery

BACKGROUND

Atrial fibrillation and atrial flutter (AF) frequently complicate coronary artery bypass surgery (CABG) and increase hospital stay as well as morbidity. Studies of drug prophylaxis to prevent AF with beta-adrenergic blocking agents administered in fixed doses have had conflicting results.

METHODS

One hundred patients were randomized to receive metoprolol or placebo following CABG. A dosing algorithm was used to achieve clinically significant beta-adrenergic blockade.

RESULTS

There was no significant difference between the incidence of AF in the metoprolol (24%) and placebo (26%) groups. However, the incidence of AF in all patients having CABG at this institution declined over the period of the study from 31% to 23% (P < .025), in association with the adoption of a continuous technique of cardioplegia delivery.

CONCLUSIONS

Metoprolol is not efficacious for the prevention of post-CABG AF even when dosage is titrated to achieve clinical evidence of beta blockade. It is likely that the adoption of a continuous cardioplegia technique caused a reduction in our incidence of post-CABG AF.

The shift toward a managed care environment in a multispecialty group practice model. Looking for reciprocal benefits

Managed care is notably affecting the practice of surgery in the United States. Four principal elements are subject to change: (1) patient care patterns, (2) ethics, (3) education and research, and (4) surgeon compensation. The Virginia Mason Clinic, a multispecialty group practice, is adapting to the demands of managed and capitated care. With the patient as the primary focus of effort, the goal is to create optimum value in health care. The principles of Continuous Quality Improvement are used to increase value in health care by ensuring appropriate treatment with optimum outcome at reasonable cost. Practice patterns are shifting to provide value to patients and payers. Ethical conflicts threaten but have been avoided. Surgical education remains unaffected, but future funding is problematic. The emphasis in surgical research has shifted toward outcome-based studies. The conflict between work effort and resource conservation as determinants of physician compensation is less for surgical than for medical practitioners. Although the principal benefactors of the shift toward managed care have been the payers, patients have gained modestly through efficiencies in the health care process and more stable insurance premiums. The satisfaction level of the surgeons in our multispecialty group practice remains high. Surgical research is thriving, volumes and case mix remain excellent, and changes in practice pattern have enabled us to increase efficiency without compromising patient care.

Hospitalisation for adverse events related to drug therapy: incidence, avoidability and costs

OBJECTIVES

To determine the incidence of hospital admissions for adverse events related to drug therapy, and to assess whether these drug-related admissions (DRAs) could have been reasonably prevented.

SETTING

A tertiary teaching hospital.

DESIGN AND PATIENTS

Prospective assessment of all admissions through the emergency department and resulting in a stay of more than 24 hours during 30 consecutive days in November and December 1994 to determine if the admission was related to drug therapy. Cases of intentional overdose were excluded.

MAIN OUTCOME MEASURES

The number, type, causality and avoidability of drug-related admissions.

RESULTS

Of 965 admissions, 55 (5.7%) were assessed as being drug-related. Drug-related admissions (DRAs) were designated possibly (38%), probably (46%) or definitely (16%) drug-related; caused by prescribing factors (26%), patient noncompliance (27%) and adverse drug reactions (47%); and classified as definitely (5.5%), possibly (60.0%) and not (34.5%) avoidable. The estimated annual cost to the hospital for all DRAs was $3,496,956 and for unavoidable DRAs was $1,629,494.

CONCLUSION

The DRA rate we found lies around the middle of the range of other published rates. Few DRAs were judged definitely avoidable and over one-third were unavoidable. Nevertheless, the largest proportion were judged possibly avoidable. As the drugs identified in this study are clearly needed in the community, efforts to reduce DRAs must concentrate on education, counselling and monitoring of drug therapy.

Volume requirements for cardiac surgery credentialing: a critical examination. The Ad Hoc Committee on Cardiac Surgery Credentialing of The Society of Thoracic Surgeons

New volume requirements for coronary artery bypass grafting are being imposed on cardiac surgeons by hospitals, managed care groups, and others. The rationale for this is unclear. The available literature as well as additional sources relating volume and outcomes in cardiac surgery were extensively reviewed and reexamined. There are no data to conclusively indicate that outcomes of cardiac operations are related to a specific minimum number of cases performed annually by a cardiac surgeon. Each cardiothoracic surgeon should participate in a national database that permits comparison of his or her outcomes on a risk-adjusted basis with other surgeons. Until conclusive data become available that link volume to outcome, volume should not be used as a criterion for credentialing of cardiac surgeons by hospitals, managed care groups, or others. Instead, each surgeon should be evaluated on his or her individual results.

Thoracic Surgery Workforce Report. The fourth report of the Thoracic Surgery Workforce Committee of The American Association for Thoracic Surgery and The Society of Thoracic Surgeons

To determine demographics, practice patterns, and work volume of North American thoracic surgeons, we sent a detailed survey to all members of The American Association for Thoracic Surgery and The Society of Thoracic Surgeons between January and May 1993 to determine data for 1992; 3049 of 3487 (87%) thoracic surgeons responded and 2677 (88%) were in active practice. Ninety-seven percent were male and 3% female, with a mean age of 52 years. Sixty-five percent considered fee-for-service as their primary compensation mode. Only 24% do isolated subspecialty work: 2% pediatric cardiac surgery. 10% general thoracic surgery, and 12% adult cardiac surgery. Seventy-six percent of respondents do both cardiac and thoracic operations. Workload data for adult cardiac, pediatric cardiac, general thoracic, peripheral vascular, and pacemaker operations were requested. Volume data were cross-correlated with age, 10 geographic regions including Canada, type of practice, and type of compensation and were cross-checked by hospital discharge data for 1992. These data were compared with data from similar surveys performed in 1976, 1980, and 1985, under the auspices of the same two societies; these latter surveys used diplomates of the American Board of Thoracic Surgery as their database. Workloads have increased over previous surveys. Most surgeons do a wide variety of thoracic operations, and exclusive designations are in the minority.

Amphotericin B toxicity reduced by administration in fat emulsion

OBJECTIVE

To report a patient with intolerance to amphotericin B reversed by preparing the antifungal in fat emulsion 20% and to review the medical literature on innovative formulations of amphotericin B.

CASE SUMMARY

A 51-year-old man diagnosed with acute myelogenous leukemia was treated with standard induction chemotherapy. Empiric antibiotic therapy was initiated 2 days postchemotherapy; however, the patient continued to be febrile until day 7. At this time amphotericin B 35 mg/250 mL D5W over 4 hours was administered. Despite premedication, the patient experienced severe rigors, chills, and fever. As the result of continuing infusion-related adverse events, the patient refused further therapy after the third daily dose. In an attempt to reduce the infusion-related events, a trial of amphotericin B 35 mg/35 mL of fat emulsion 20% was administered over 2 hours after patient consent was obtained. Premedication was administered and the patient tolerated therapy without adverse events. Amphotericin B dosage escalations to 50 and 70 mg were tolerated similarly. During this treatment the patient became afebrile and the serum creatinine concentration decreased to normal.

DISCUSSION

Despite significant toxicities and the development of newer antifungal agents, amphotericin B remains the drug of choice for the empiric coverage of suspected fungal infection in neutropenic patients. Amphotericin B often exacerbates the nephrotoxicity of other agents characteristically prescribed in these patients. Furthermore, infusion-related events, if not intolerable, can dramatically reduce the patient's quality of life. For these reasons, novel means of amphotericin B administration are being explored.

CONCLUSIONS

The delivery of amphotericin B in a lipid diluent may have substantial benefit in reducing the nephrotoxicity and infusion-related events associated with the antifungal. Prospective clinical trial comparing lipid-complexed amphotericin B with liposomal and approved formulations of amphotericin B are essential to define potential differences in toxicity and efficacy.

Treatment of calcified cephalohematoma

This is a case report concerning the surgical treatment of a calcified cephalohematoma, which was possibly caused by an intrauterine fetal monitor. This is the first report of this particular entity as a complication of an intrauterine fetal monitor. As far as we can determine, there is no detailed information available about surgical decision making or surgical techniques for removing such lesions. We operated because of the size and persistence of the lesion. We developed a procedure in which we used the bony cap of the cephalohematoma for a cranioplasty, securing it with microplates.

Systematic survey of opinion regarding the thoracic surgery residency

To summarize this rather wide-ranging study, let us review the high points. The future practice of thoracic surgery will be increasingly affected by governmental factors and will have even greater technological dimensions. To do this work, we must continue to attract high-caliber individuals, and this is best accomplished by the early and continuing involvement in the educational process of strong role models from our field. These future surgeons must be motivated to do good work and should have high ethical standards as well as maturity and high intelligence. Experienced, involved faculty leading the residents through a broad program that offers graduated assumption of clinical and leadership responsibilities will facilitate the development of mature clinical judgment. Residents must be taught the clinical skills necessary to do all thoracic operations, leaving subspecialization to postresidency fellowships. The educational program should be humane in its demands and collegial in its application. It should incorporate experiences beyond the operating room, including the opportunity to read, think, and interact with local mentors and colleagues from around the country. The requirements of certification should not be so rigid as to preclude the development of different pathways to the same end. Likewise, although the accreditation process must protect the resident from exploitation, it must not be so restrictive that it does not allow for educational innovation and justifiable differences among programs. These are the thoughtful opinions of our colleagues. They deserve serious consideration.

Selection of patients for same-day coronary bypass operations

Between March 15, 1990, and December 31, 1991, we admitted to the Virginia Mason Hospital for isolated coronary bypass operations 175 consecutive patients with chronic, stable angina pectoris who had prior coronary arteriography. One hundred patients were admitted on the same day as their operations, and 75 patients, deemed to be at higher risk, were admitted 1 day before the operation. Postoperative progress of all patients was monitored by means of a clinical pathway form with physiologic and activity measures plotted against postoperative days. We found no difference in age, sex, or total number of comorbidity factors. Diabetes and ejection fraction less than 0.50 were significantly more common in preoperatively admitted patients and were independently predictive of admitting group. Significant differences between surgeons in the proportion of same-day patients admitted could not be explained by differences in common risk factors. There was no significant difference in postoperative major or minor complications or number of clinical pathway deviations, but two deaths occurred in patients admitted preoperatively. Average total hospital stay was 1 1/2 days less for same-day patients, a highly significant difference. Total hospital charges averaged $19,000 for the series and were $286 more for preoperatively admitted patients, a difference that was not statistically significant. Patients admitted selectively for same-day coronary bypass are not at risk for an increased number of complications. Although their hospital stay is reduced, the reduction of their hospital charges is minimal. Preoperative admission of patients with comorbidity requiring medical management or with physical incapacity remains justified, and admitting decisions should remain with the operating surgeon, not third parties.

Pharmacy-coordinated, multidisciplinary adverse drug reaction program

To date, the stated program objectives have been met. There is a heightened awareness of ADRs, and the program has had a positive impact on patient care. More work is needed in the prevention of ADRs as opposed to their tabulation. Future educational efforts will focus on how reporting suspected ADRs can positively impact patient care.

Mitral valve reconstruction

Modern repair techniques allow reconstruction rather than replacement of the mitral valve (MV) in the majority of patients requiring operation. Such patients are now older and more likely to have nonrheumatic MV disease than those treated in former years. A continuing experience with MV reconstruction was reviewed to determine its safety and efficacy. In 50 patients undergoing isolated MV reconstructions, there have been no postoperative deaths. In 36 patients undergoing mitral reconstruction combined with other cardiac procedures, there have been 5 deaths (14%). Three patients have required MV replacement for an inadequate repair as determined by evaluation during the repair or by intraoperative transesophageal echocardiography (TEE) following cardiopulmonary bypass. Overall complications have included five reoperations for bleeding, two perioperative myocardial infarctions, two strokes, and one aortic dissection. The majority of patients maintain an improved functional state after operation. Multiple reconstructive maneuvers are now available, and the elements of any given reconstruction depend on the pathoanatomy of the valve. Intraoperative TEE has been invaluable in planning, evaluating, and modifying repairs. At present, over 70% of all MV operations are reconstructions, and the most common recent indication for MV replacement is a malfunctioning prosthetic MV rather than native valve disease.

Continuing experience with the automatic implantable cardioverter defibrillator

The automatic implantable cardioverter defibrillator (AICD) is now used commonly in the management of malignant ventricular arrhythmias. Its use may obviate the need for antiarrhythmic drugs or endocardial resection. We reviewed our continuing experience with the AICD to determine its safety and efficacy. Since June 1987, 102 patients (mean age: 63 years) who survived out-of-hospital ventricular fibrillation or hemodynamically unstable ventricular tachycardia not associated with acute myocardial infarction underwent implantation of an AICD. There were three operative deaths and nine complications. Eighty-nine patients are alive. No patient has experienced sudden cardiac death. Forty-two patients (43%) have had 1 or more AICD discharges associated with symptoms of cardiac arrest. During AICD implantation, it appears preferable to configure lead placement by individual patient characteristics rather than by a rigid protocol. The relative safety and efficacy of the AICD support its use as an alternative to toxic medications or more dangerous endocardial resection in suboptimal candidates.

Hepatobiliary excretion of bacterial formyl-methionyl peptides in rat. Structure activity studies

The bacterial chemotactic peptide formyl-met-leu-phe and its radioiodinated analog formyl-met-leu-[125I]tyr are rapidly excreted by the liver into bile following portal or systemic venous infusions in rats or after absorption from the gut lumen. To determine the molecular structural requirements for hepatobiliary excretion of formyl-methionyl peptides, structure-activity studies using portal venous infusions of 24 structural analogs of formyl-met-leu-tyr were performed in rats with biliary cannulae. Hepatic extraction of peptides was studied in vivo using external gamma counting after portal infusion. Efficient hepatobiliary excretion was not restricted to bioactive formyl peptides, but showed a broad specificity for different amino-acylated (formyl, acetyl, propionyl, carbobenzoxy) di- and tripeptides and no requirement for methionine in position one or for a free carboxy terminus. However, nonacylated peptides and an acyl-amino acid showed little excretion. Hepatic extraction of peptide was also related to N-acylation. Hepatic extraction and excretion of N-acyl peptides were also related to hydrophobicity. Thus, the presence of an N-acyl group is the key determinant of biliary excretion of inflammatory bacterial f-met peptides in the rat.

Routine computed tomographic scans, selective mediastinoscopy, and other factors in evaluation of lung cancer

Routine computed tomographic scan is advocated as the best noninvasive method of evaluating mediastinal nodes for cancer spread. Positive studies should be confirmed histologically. Large size, central location, unfavorable cell type, poor cellular differentiation of the primary cancer, and weight loss also correlate with increased likelihood of mediastinal involvement.