Platinum and microspherule peaks as chronostratigraphic markers for onset of the Younger Dryas at Wakulla Springs, Florida

Anomalous peak abundances of platinum and Fe-rich microspherules with high-temperature minerals have previously been demonstrated to be a chronostratigraphic marker for the lower Younger Dryas Boundary (YDB) dating to 12.8 ka. This study used Bayesian analyses to test this hypothesis in multiple sequences (units) of sandy, weakly stratified sediments at Wakulla Springs, Florida. Our investigations included platinum geochemistry, granulometry, optically stimulated luminescence (OSL) dating, and culturally dated lithics. In addition, sediments were analyzed using scanning electron microscopy and energy dispersive x-ray spectroscopy to investigate dendritic, iron-rich microspherules previously identified elsewhere in peak abundances at the onset of the Younger Dryas (YD) cool climatic episode. Our work has revealed this abundance peak in platinum and dendritic spherules in five sediment sequences at Wakulla Springs. A YDB age of ~ 12.8 ka for the platinum and spherule chronostratigraphic datum in these Wakulla Springs sequences is consistent with the archaeological data and OSL dating. This study confirms the utility of this YDB datum layer for intersequence correlation and for assessing relative ages of Paleoamerican artifacts, including those of likely Clovis, pre-Clovis, and post-Clovis age and their possible responses to environmental changes known to have occurred during the Younger Dryas cool climatic episode.

Paleoamerican exploitation of extinct megafauna revealed through immunological blood residue and microwear analysis, North and South Carolina, USA

Previous immunological studies in the eastern USA have failed to establish a direct connection between Paleoamericans and extinct megafauna species. The lack of physical evidence for the presence of extinct megafauna begs the question, did early Paleoamericans regularly hunt or scavenge these animals, or were some megafauna already extinct? In this study of 120 Paleoamerican stone tools from across North and South Carolina, we investigate this question using crossover immunoelectrophoresis (CIEP). We find immunological support for the exploitation of extant and extinct megafauna, including Proboscidea, Equidae, and Bovidae (possibly Bison antiquus), on Clovis points and scrapers, as well as possible early Paleoamerican Haw River points. Post-Clovis points tested positive for Equidae and Bovidae but not Proboscidea. Microwear results are consistent with projectile usage, butchery, fresh- and dry hide scraping, the use of ochre-coated dry hides for hafting, and dry hide sheath wear. This study represents the first direct evidence of the exploitation of extinct megafauna by Clovis and other Paleoamerican cultures in the Carolinas and more broadly, across the eastern United States, where there is generally poor to non-existent faunal preservation. Future CIEP analysis of stone tools may provide evidence on the timing and demography of megafaunal collapse leading to eventual extinction.

Age-related injury patterns resulting from knife violence in an urban population

Interpersonal violence involving knives is a major public health problem. The majority of patients are young people in urban areas, but little is known about age-specific patterns of injury and recent trends in injury characteristics. We performed a retrospective cohort study of all patients presenting to an urban major trauma centre with stab injuries resulting from assault between 2012 and 2018. A total of 3583 patients were included. Young people (age under 25) were more likely to have sustained multiple stab wounds compared to older people (43% vs 35%, p < 0.001) and had significantly higher rates of stab injuries involving the lower limbs, groin and buttocks. The annual number of injuries increased steadily during the study period in patients aged under 25 (r² = 0.82, p = 0.005) and those over 25 (r² = 0.95, p < 0.001). Over time, limb and junctional injuries accounted for an increasing proportion of stab wounds in young people, overtaking torso injuries as most common pattern of injury by the end of the study period. These findings illustrate the influence of age on injury patterns resulting from knife violence, and support the expansion of outreach initiatives promoting bystander-delivered haemorrhage control of extremity wounds.

1473 Urology Consent Forms at a District General Hospital – a Quality Improvement Project

Aim

Consent is a core component of interaction between patients and healthcare professionals. Prior to surgery, forms are completed to record patient consent. As well as containing risks and benefits of the procedure, the consent form, as per guidelines1,2, must be legible and suitable to a patient’s capacity. To evaluate compliance with local and national guidelines, a quality improvement project was undertaken at a district general hospital.

Method

Over a three-week period 30 urology consent forms were selected to assess adherence to local and national guidelines. The appropriateness of consent form, patient signature, legibility, acronym use and whether the patient was offered a carbon copy were assessed. After initial data collection, all urology staff consenting patients were notified of the findings and how best to improve guideline adherence. A further three-week data collection was undertaken, though the sample set was small due to Coronavirus and Christmas.

Results

The results confirmed that patients had appropriate consent forms filled out and were signed appropriately. After intervention, there was clear improvement in legibility, with no low legibility consent forms, and 100% vs 83% high or moderate legibility between data sets. Intervention also resulted in significant reduction of acronym use; 33% vs 60%. More patients were also offered to retain a carbon copy; 89% vs 40%.

Conclusions

Through this intervention of highlighting local and national guidance as compared to current practice, compliance drastically improved. As the pandemic subsides, we hope regular emails to surgical teams will improve consent form completion to better patient care.

Evidence of Cosmic Impact at Abu Hureyra, Syria at the Younger Dryas Onset (~12.8 ka): High-temperature melting at >2200 °C

At Abu Hureyra (AH), Syria, the 12,800-year-old Younger Dryas boundary layer (YDB) contains peak abundances in meltglass, nanodiamonds, microspherules, and charcoal. AH meltglass comprises 1.6 wt.% of bulk sediment, and crossed polarizers indicate that the meltglass is isotropic. High YDB concentrations of iridium, platinum, nickel, and cobalt suggest mixing of melted local sediment with small quantities of meteoritic material. Approximately 40% of AH glass display carbon-infused, siliceous plant imprints that laboratory experiments show formed at a minimum of 1200°-1300 °C; however, reflectance-inferred temperatures for the encapsulated carbon were lower by up to 1000 °C. Alternately, melted grains of quartz, chromferide, and magnetite in AH glass suggest exposure to minimum temperatures of 1720 °C ranging to >2200 °C. This argues against formation of AH meltglass in thatched hut fires at 1100°-1200 °C, and low values of remanent magnetism indicate the meltglass was not created by lightning. Low meltglass water content (0.02-0.05% H₂O) is consistent with a formation process similar to that of tektites and inconsistent with volcanism and anthropogenesis. The wide range of evidence supports the hypothesis that a cosmic event occurred at Abu Hureyra ~12,800 years ago, coeval with impacts that deposited high-temperature meltglass, melted microspherules, and/or platinum at other YDB sites on four continents.

Sediment Cores from White Pond, South Carolina, contain a Platinum Anomaly, Pyrogenic Carbon Peak, and Coprophilous Spore Decline at 12.8 ka

A widespread platinum (Pt) anomaly was recently documented in Greenland ice and 11 North American sedimentary sequences at the onset of the Younger Dryas (YD) event (~12,800 cal yr BP), consistent with the YD Impact Hypothesis. We report high-resolution analyses of a 1-meter section of a lake core from White Pond, South Carolina, USA. After developing a Bayesian age-depth model that brackets the late Pleistocene through early Holocene, we analyzed and quantified the following: (1) Pt and palladium (Pd) abundance, (2) geochemistry of 58 elements, (3) coprophilous spores, (4) sedimentary organic matter (OC and sedaDNA), (5) stable isotopes of C (δ13C) and N (δ15N), (6) soot, (7) aciniform carbon, (8) cryptotephra, (9) mercury (Hg), and (10) magnetic susceptibility. We identified large Pt and Pt/Pd anomalies within a 2-cm section dated to the YD onset (12,785 ± 58 cal yr BP). These anomalies precede a decline in coprophilous spores and correlate with an abrupt peak in soot and C/OC ratios, indicative of large-scale regional biomass burning. We also observed a relatively large excursion in δ15N values, indicating rapid climatic and environmental/hydrological changes at the YD onset. Our results are consistent with the YD Impact Hypothesis and impact-related environmental and ecological changes.

Surface tension determines tissue shape and growth kinetics

The collective self-organization of cells into three-dimensional structures can give rise to emergent physical properties such as fluid behavior. Here, we demonstrate that tissues growing on curved surfaces develop shapes with outer boundaries of constant mean curvature, similar to the energy minimizing forms of liquids wetting a surface. The amount of tissue formed depends on the shape of the substrate, with more tissue being deposited on highly concave surfaces, indicating a mechano-biological feedback mechanism. Inhibiting cell-contractility further revealed that active cellular forces are essential for generating sufficient surface stresses for the liquid-like behavior and growth of the tissue. This suggests that the mechanical signaling between cells and their physical environment, along with the continuous reorganization of cells and matrix is a key principle for the emergence of tissue shape.

Impact-related microspherules in Late Pleistocene Alaskan and Yukon "muck" deposits signify recurrent episodes of catastrophic emplacement

Large quantities of impact-related microspherules have been found in fine-grained sediments retained within seven out of nine, radiocarbon-dated, Late Pleistocene mammoth (Mammuthus primigenius) and bison (Bison priscus) skull fragments. The well-preserved fossils were recovered from frozen “muck” deposits (organic-rich silt) exposed within the Fairbanks and Klondike mining districts of Alaska, USA, and the Yukon Territory, Canada. In addition, elevated platinum abundances were found in sediment analysed from three out of four fossil skulls. In view of this new evidence, the mucks and their well-preserved but highly disrupted and damaged vertebrate and botanical remains are reinterpreted in part as blast deposits that resulted from several episodes of airbursts and ground/ice impacts within the northern hemisphere during Late Pleistocene time (~46–11 ka B.P.). Such a scenario might be explained by encounters with cometary debris in Earth-crossing orbits (Taurid Complex) that was generated by fragmentation of a large short-period comet within the inner Solar System.

ecancermedicalscience.. [PMID: 22276069 PMCID: PMC3239171 DOI: 10.3332/ecancer.2011.237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Details on the 28-year treatment history of a patient with an endocrine-responsive breast cancer are provided. She was originally diagnosed as having a T1N0M0 cancer after a modified radical mastectomy at age 41. Fifteen years later, in 1998, she presented with hemoptysis and pleuritic chest pain: a 10 cm right atrial tumor and estrogen receptor (ER) positive endobronchial and adjacent lung parenchyma adenocarcinoma were documented. Epithelial markers normalized as she manifested a partial response (PR) lasting 3 years with tamoxifen treatment. From 2001 to 2007 she benefitted from exemestane treatment. Upon progression in the previous lung area and left adrenal, exemestane withdrawal led to transient decrease in markers. Six months later (in July 2008), with growth in her adrenal tumor, laparoscopic adrenalectomy was performed: in addition to ER positivity, the tumor showed Her2 overexpression and amplification. She has subsequently had some control of disease with fulvestrant, letrozole + trastuzumab, and subsequently letrozole + lapatinib. In addition to the chronicity of disease, this history illustrates the expanding range of treatments available for endocrine-responsive breast cancer commensurate to our greater understanding of tumor biology.

OPTIMUM: a protocol for a multicentre randomised controlled trial comparing Out Patient Talc slurry via Indwelling pleural catheter for Malignant pleural effusion vs Usual inpatient Management

INTRODUCTION

The development of malignant pleural effusion (MPE) results in disabling breathlessness, pain and reduced physical capability with treatment a palliative strategy. Ambulatory management of MPE has the potential to improve quality of life (QoL). The OPTIMUM trial is designed to determine whether full outpatient management of MPE with an indwelling pleural catheter (IPC) and pleurodesis improves QoL compared with traditional inpatient care with a chest drain and talc pleurodesis. OPTIMUM is currently open for any centres interested in collaborating in this study.

METHODS AND ANALYSIS

OPTIMUM is a multicentre non-blinded randomised controlled trial. Patients with a diagnosis of MPE will be identified and screened for eligibility. Consenting participants will be randomised 1:1 either to an outpatient ambulatory pathway using IPCs and talc pleurodesis or standard inpatient treatment with chest drain and talc pleurodesis as per British Thoracic Society guidelines. The primary outcome measure is global health-related QoL at 30 days measured using the EORTC QLQ-C30 questionnaire. Secondary outcome measures include breathlessness and pain measured using a 100 mm Visual Analogue Scale and health-related QoL at 60 and 90 days. A sample size of 142 patients is needed to demonstrate a clinically significant difference of 8 points in global health status at 30 days, for an 80% power and a 5% significance level.

ETHICS AND DISSEMINATION

The study has been approved by the NRES Committee South East Coast-Brighton and Sussex (reference 15/LO/1018). The trial results will be published in peer-reviewed journals and presented at scientific conferences.

TRIAL REGISTRATION NUMBERS

UKCRN19615 and ISRCTN15503522; Pre-results.

A proteomic approach for the rapid, multi-informative and reliable identification of blood

Blood evidence is frequently encountered at the scene of violent crimes and can provide valuable intelligence in the forensic investigation of serious offences.

The influence of mothers' and fathers' sensitivity in the first year of life on children's cognitive outcomes at 18 and 36 months

BACKGROUND

There has been increasing interest in the relative effects of mothers' and fathers' interactions with their infants on later development. However to date there has been little work on children's cognitive outcomes.

METHODS

We examined the relative influence of fathers' and mothers' sensitivity during interactions with their children at the end of the child's first year (10-12 months, n = 97), on child general cognitive development at 18 months and language at 36 months.

RESULTS

Both parents' sensitivity was associated with cognitive and language outcomes in univariate analyses. Mothers' sensitivity, however, appeared to be associated with family socio-demographic factors to a greater extent that fathers' sensitivity. Using path modelling the effect of paternal sensitivity on general cognitive development at 18 months and language at 36 months was significantly greater than the effect of maternal sensitivity, when controlling for socio-demographic background. In relation to language at 36 months, there was some evidence that sensitivity of one parent buffered the effect of lower sensitivity of the other parent.

CONCLUSIONS

These findings suggest that parental sensitivity can play an important role in children's cognitive and language development, and that higher sensitivity of one parent can compensate for the lower sensitivity of the other parent. Replication of these findings, however, is required in larger samples.

Pneumoperitoneum without visceral trauma: an under-recognised phenomenon after blast injury?

OBJECTIVES

The management of patients who have sustained blast injuries poses an important challenge for military healthcare professionals. Current military operations are generating large numbers of casualties and modern military healthcare facilities are increasingly using CT scanning to facilitate their management. This small case series serves to draw attention to a rare (or possibly under-reported) phenomenon after blast injury.

METHODS AND RESULTS

We report two patients exposed to blast who had pneumoperitoneum identified by CT scan but who did not have abdominal visceral injury or ballistic peritoneal violation.

DISCUSSION

The use of cross-sectional imaging is leading to the recognition of otherwise occult injury. Military practitioners should be aware of this injury pattern when using CT to help select patients for conservative management after abdominal blast injury.

Npas4 is activated by melatonin, and drives the clock gene Cry1 in the ovine pars tuberalis

Seasonal mammals integrate changes in the duration of nocturnal melatonin secretion to drive annual physiologic cycles. Melatonin receptors within the proximal pituitary region, the pars tuberalis (PT), are essential in regulating seasonal neuroendocrine responses. In the ovine PT, melatonin is known to influence acute changes in transcriptional dynamics coupled to the onset (dusk) and offset (dawn) of melatonin secretion, leading to a potential interval-timing mechanism capable of decoding changes in day length (photoperiod). Melatonin offset at dawn is linked to cAMP accumulation, which directly induces transcription of the clock gene Per1. The rise of melatonin at dusk induces a separate and distinct cohort, including the clock-regulated genes Cry1 and Nampt, but little is known of the up-stream mechanisms involved. Here, we used next-generation sequencing of the ovine PT transcriptome at melatonin onset and identified Npas4 as a rapidly induced basic helix-loop-helix Per-Arnt-Sim domain transcription factor. In vivo we show nuclear localization of NPAS4 protein in presumptive melatonin target cells of the PT (α-glycoprotein hormone-expressing cells), whereas in situ hybridization studies identified acute and transient expression in the PT of Npas4 in response to melatonin. In vitro, NPAS4 forms functional dimers with basic helix loop helix-PAS domain cofactors aryl hydrocarbon receptor nuclear translocator (ARNT), ARNT2, and ARNTL, transactivating both Cry1 and Nampt ovine promoter reporters. Using a combination of 5′-deletions and site-directed mutagenesis, we show NPAS4-ARNT transactivation to be codependent upon two conserved central midline elements within the Cry1 promoter. Our data thus reveal NPAS4 as a candidate immediate early-response gene in the ovine PT, driving molecular responses to melatonin.

Opportunities for improvement in the management of patients who die from haemorrhage after trauma

BACKGROUND

Bleeding is the leading cause of preventable death after injury. This retrospective study aimed to characterize opportunities for performance improvement (OPIs) identified in patients who died from bleeding and were considered by the quality improvement system of a major trauma centre.

METHODS

All trauma deaths in 2006-2010 were discussed at the trauma morbidity and mortality meeting. Deaths from haemorrhage were identified and subjected to qualitative and quantitative evaluation. OPIs were identified and remedial action was taken.

RESULTS

During the study interval there were 7511 trauma team activations; 423 patients died. Haemorrhage was the second most common cause of death, in 112 patients, and made a substantial contribution to death in a further 15. For 84 of these 127 patients, a total of 150 OPIs were identified. Most arose in the emergency department, but involved personnel from many departments. Problems with decision-making were more common than errors in technical skill. OPIs frequently involved the decision between surgery, radiology and further investigation. Delayed and inappropriate surgery occurred even when investigation and diagnosis were appropriate. The mortality rate among patients presenting in shock fell significantly over the study interval (P < 0·026).

CONCLUSION

Problems with judgement are more common than those of skill. Death from traumatic haemorrhage is associated with identifiable, remediable failures in care. The implementation of a systematic trauma quality improvement system was associated with a fall in the mortality rate among patients presenting in shock.

Can residents be effective trauma team leaders in a major trauma centre?

OBJECTIVE

The overall objective of this study was to compare senior Emergency Department (ED) trainees (residents) with consultant trauma team leaders, assessing their influence on trauma team performance and patient outcomes. We aimed to identify the effect of seniority of leader on time-based performance measures and clinical outcomes.

METHODS

This retrospective study of prospectively collected data was conducted in an urban Major Trauma Centre which has a well-established trauma team. For the period covered by this study the trauma team was led by either an ED consultant or specialist registrar having completed a local trauma team leader development programme. Data from all adult trauma team activations for seriously injured trauma patients (ISS - Injury Severity Score >15) presenting between 1st January 2008 and 31st October 2009 were included. Performance measures included time to FAST, time to CT scan and time to haemorrhage control. Patient outcomes were mortality, critical care and hospital length of stay.

RESULTS

There were 579 patients seriously injured in the study period. Trainees led 126 (22%) of the trauma teams. Significant differences in times to diagnostics or haemorrhage control between trainees and consultants were only seen in patients presenting with shock. Compared with trainees, consultant team leaders were significantly more likely to achieve targets for diagnostic imaging (FAST <15 min: consultants 97% vs. 33% trainees, p<0.01; CT scan <60 min: 76% vs. 50%, p<0.01) and haemorrhage control (surgery or angiography <60 min: 82% vs. 54%, p<0.001). There was no significant difference in overall mortality between consultants and trainees (consultants 25% vs. trainees 27%, p 1.00). Critical care length of stay was also the same for both (consultants median 5 days vs. trainees median 5 days).

CONCLUSIONS

Consultant team leaders improve team performance, resulting in shorter times to diagnostic imaging, and faster transfer to haemorrhage control. The greatest benefit seems to be for bleeding patients. Clinical outcomes were similar for trainees and consultants in our major trauma centre.

The measurement of the responses to different odour intensities of `boar taint' using a sensory panel and an electronic nose

This study explored the possibility of using an electronic nose (e-nose) with a 12-conducting-polymer sensor array combined with pattern recognition routines to discriminate between varying intensities of boar taint. A set of samples in a model system comprising a neutral lipid base containing varying combinations of androstenone and skatole were tested, as were pork fat samples. The e-nose responses for pork fat were calibrated against those given by a trained 10-member sensory panel for abnormal odour of the same samples from a total of 60 Large White cross-bred pigs. The e-nose responses related strongly to those of the sensory panel with a significant (p<0·01) canonical correlation of 0·78. The data set was used to develop a discriminant function for grouping pork samples into three `response classes': normal, doubtful and abnormal. Based on this, the e-nose identified all the abnormal samples correctly. However, 16% of the normal samples were also classified as abnormal. It was concluded that, in general, the electronic nose can discriminate between different levels of boar taint and that although a high specificity of sensors to androstenone and skatole may be desirable it may not be entirely important to the development and configuration of a boar taint sensor array.

Contrast ureteropyelography in theatre: standardised flowchart reporting

INTRODUCTION

Urologists perform retrograde contrast studies of the ureters and pelvicalyceal systems in the operating theatre, both for diagnostic purposes and to guide instrumentation. We describe the development of a set of guidelines that aim to standardise the diagnostic quality of these studies and to reduce radiation dose to the patient and theatre staff. The guidelines incorporate a reporting template that allows a urologist's written report to be made available on the picture archiving and com- munication system (PACS) for subsequent multidisciplinary review.

METHODS

Three cycles of audit were conducted to assess the implementation of the guidelines. An independent reviewer rated image quality and screening times. During the audit cycle, the presentation of the guidelines was honed. The end prod- uct is a flowchart and reporting template for use by urologists in the operating theatre.

RESULTS

Phase 1 of the audit included 63 studies, phase 2 included 42 studies and phase 3 included 46 studies. The results demonstrate significant improvements in the number of good quality studies and in the recording of control, contrast and post-procedure images. The mean screening time decreased from 5.0 minutes in phase 1 to 3.2 minutes in phase 3. In phase 3, when in-theatre reporting of the studies by the urologist was added, the handwritten report was scanned in and made available on PACS in 43 of 46 cases (93%). CONCLUSIONS Introduction of guidelines improved retrograde contrast study quality and reduced screening times. A system has been developed to store appropriate pictures and a urologist's report of the study on PACS.

Evidence from central Mexico supporting the Younger Dryas extraterrestrial impact hypothesis

We report the discovery in Lake Cuitzeo in central Mexico of a black, carbon-rich, lacustrine layer, containing nanodiamonds, microspherules, and other unusual materials that date to the early Younger Dryas and are interpreted to result from an extraterrestrial impact. These proxies were found in a 27-m-long core as part of an interdisciplinary effort to extract a paleoclimate record back through the previous interglacial. Our attention focused early on an anomalous, 10-cm-thick, carbon-rich layer at a depth of 2.8 m that dates to 12.9 ka and coincides with a suite of anomalous coeval environmental and biotic changes independently recognized in other regional lake sequences. Collectively, these changes have produced the most distinctive boundary layer in the late Quaternary record. This layer contains a diverse, abundant assemblage of impact-related markers, including nanodiamonds, carbon spherules, and magnetic spherules with rapid melting/quenching textures, all reaching synchronous peaks immediately beneath a layer containing the largest peak of charcoal in the core. Analyses by multiple methods demonstrate the presence of three allotropes of nanodiamond: n-diamond, i-carbon, and hexagonal nanodiamond (lonsdaleite), in order of estimated relative abundance. This nanodiamond-rich layer is consistent with the Younger Dryas boundary layer found at numerous sites across North America, Greenland, and Western Europe. We have examined multiple hypotheses to account for these observations and find the evidence cannot be explained by any known terrestrial mechanism. It is, however, consistent with the Younger Dryas boundary impact hypothesis postulating a major extraterrestrial impact involving multiple airburst(s) and and/or ground impact(s) at 12.9 ka.

A major trauma centre is a specialty hospital not a hospital of specialties

BACKGROUND

High estimates of preventable death rates have renewed the impetus for national regionalization of trauma care. Institution of a specialist multidisciplinary trauma service and performance improvement programme was hypothesized to have resulted in improved outcomes for severely injured patients.

METHODS

This was a comparative analysis of data from the Royal London Hospital (RLH) trauma registry and Trauma Audit and Research Network (England and Wales), 2000-2005. Preventable mortality was evaluated by prospective analysis of the RLH performance improvement programme.

RESULTS

Mortality from critical injury at the RLH was 48 per cent lower in 2005 than 2000 (17.9 versus 34.2 per cent; P = 0.001). Overall mortality rates were unchanged for acute hospitals (4.3 versus 4.4 per cent) and other multispecialty hospitals (8.7 versus 7.3 per cent). Secondary transfer mortality in critically injured patients was 53 per cent lower in the regional network than the national average (5.2 versus 11.0 per cent; P = 0.001). Preventable death rates fell from 9 to 2 per cent (P = 0.040) and significant gains were made in critical care and ward bed utilization.

CONCLUSION

Institution of a specialist trauma service and performance improvement programme was associated with significant improvements in outcomes that exceeded national variations.

Nanodiamonds in the Younger Dryas boundary sediment layer

We report abundant nanodiamonds in sediments dating to 12.9 +/- 0.1 thousand calendar years before the present at multiple locations across North America. Selected area electron diffraction patterns reveal two diamond allotropes in this boundary layer but not above or below that interval. Cubic diamonds form under high temperature-pressure regimes, and n-diamonds also require extraordinary conditions, well outside the range of Earth's typical surficial processes but common to cosmic impacts. N-diamond concentrations range from approximately 10 to 3700 parts per billion by weight, comparable to amounts found in known impact layers. These diamonds provide strong evidence for Earth's collision with a rare swarm of carbonaceous chondrites or comets at the onset of the Younger Dryas cool interval, producing multiple airbursts and possible surface impacts, with severe repercussions for plants, animals, and humans in North America.

Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling

A carbon-rich black layer, dating to approximately 12.9 ka, has been previously identified at approximately 50 Clovis-age sites across North America and appears contemporaneous with the abrupt onset of Younger Dryas (YD) cooling. The in situ bones of extinct Pleistocene megafauna, along with Clovis tool assemblages, occur below this black layer but not within or above it. Causes for the extinctions, YD cooling, and termination of Clovis culture have long been controversial. In this paper, we provide evidence for an extraterrestrial (ET) impact event at approximately equal 12.9 ka, which we hypothesize caused abrupt environmental changes that contributed to YD cooling, major ecological reorganization, broad-scale extinctions, and rapid human behavioral shifts at the end of the Clovis Period. Clovis-age sites in North American are overlain by a thin, discrete layer with varying peak abundances of (i) magnetic grains with iridium, (ii) magnetic microspherules, (iii) charcoal, (iv) soot, (v) carbon spherules, (vi) glass-like carbon containing nanodiamonds, and (vii) fullerenes with ET helium, all of which are evidence for an ET impact and associated biomass burning at approximately 12.9 ka. This layer also extends throughout at least 15 Carolina Bays, which are unique, elliptical depressions, oriented to the northwest across the Atlantic Coastal Plain. We propose that one or more large, low-density ET objects exploded over northern North America, partially destabilizing the Laurentide Ice Sheet and triggering YD cooling. The shock wave, thermal pulse, and event-related environmental effects (e.g., extensive biomass burning and food limitations) contributed to end-Pleistocene megafaunal extinctions and adaptive shifts among PaleoAmericans in North America.

Effects of rapid antigen degradation and VEE glycoprotein specificity on immune responses induced by a VEE replicon vaccine

Genetic vaccines are engineered to produce immunogens de novo in the cells of the host for stimulation of a protective immune response. In some of these systems, antigens engineered for rapid degradation have produced an enhanced cellular immune response by more efficient entry into pathways for processing and presentation of MHC class I peptides. VEE replicon particles (VRP), single cycle vaccine vectors derived from Venezuelan equine encephalitis virus (VEE), are examined here for the effect of an increased rate of immunogen degradation on VRP vaccine efficacy. VRP expressing the matrix capsid (MA/CA) portion of SIV Gag were altered to promote rapid degradation of MA/CA by various linkages to co-translated ubiquitin or by destabilizing mutations and were used to immunize BALB/c mice for quantitation of anti-MA/CA cellular and humoral immune responses. Rapid degradation by the N-end rule correlated with a dampened immune response relative to unmodified MA/CA when the VRP carried a glycoprotein spike from an attenuated strain of VEE. In contrast, statistically equivalent numbers of IFNgamma(+)T-cells resulted when VRP expressing unstable MA/CA were packaged with the wild-type VEE glycoproteins. These results suggest that the cell types targeted in vivo by VRP carrying mutant or wild type glycoprotein spikes are functionally different, and are consistent with previous findings suggesting that wild-type VEE glycoproteins preferentially target professional antigen presenting cells that use peptides generated from the degraded antigen for direct presentation on MHC.

A human ImmunoChip cDNA microarray provides a comprehensive tool to study immune responses

DNA microarray technology has developed rapidly in recent years and has become an essential tool, providing novel approaches to biomedical research. In this paper, we describe a self-designed ImmunoChip cDNA array for immunological research. With a comprehensive selection of genes of interest, we can focus on key signalling pathways and molecular mechanisms at relatively low cost compared to commercial platforms which are usually targeted at global screening of gene expression. To validate the efficiency of the ImmunoChip, we studied T helper cell polarization to functionally distinct subsets (Th1 and Th2). We also developed a tool for quality control of cDNA microarrays that assesses the technical quality of an ImmunoChip. The information produced with the quality control tool is shown to be valuable for extracting correct information from cDNA microarrays. Gene expression measurements with ImmunoChip are in agreement with the results obtained using oligonucleotide microarrays and with published quantitative RT-PCR data. The ImmunoChip provides reliable measurements and gives new insights into various aspects of human immune responses.

Parkin-proven disease: common founders but divergent phenotypes

OBJECTIVE

To compare and contrast clinical and genetic findings in six probands with parkinsonism with a parkin exon 3 438- to 477-bp deletion (Ex3Delta40) to search for evidence of a common founder.

METHOD

Clinical review, parkin gene sequencing, dosage studies, and high-resolution genotype/haplotype analysis were performed.

RESULTS

All subjects had two or more signs consistent with a diagnosis of possible or probable PD with age at onset younger than 45 years (mean +/- SD 29.3 +/- 10.2 years, range 16 to 42 years). Affected individuals were either homozygotes, compound heterozygotes, or Ex3Delta40 carriers with one normal parkin allele. Haplotype analysis revealed both Ex3Delta40 and Ex7 924 C-->T (R275W) mutations originated from common founders, the former most probably of Irish descent. Although three cases had Ex7 924 C-->T (R275W) and Ex3Delta40 mutations, their clinical presentation and mode of inheritance were variable.

CONCLUSION

Parkin mutations on common parkin haplotypes provide testable hypotheses of parkin function in genetically defined parkinsonism.

Evidence to suggest biased phenotypes in children with Attention Deficit Hyperactivity Disorder from completely ascertained trios

The transmission disequilibrium test (TDT) is widely used as a robust statistical method to test for genetic association due to linkage based upon analysis of parent-proband trios. The TDT and other family-based tests (eg haplotype relative risk method) are commonly used in association studies including those of ADHD because of concerns that the case-control design has a strong tendency for false positives due to poor matching between cases and controls. Unfortunately, it is not always possible to obtain DNA from both parents in studies of this design, even where the onset of disorder is in childhood, and usually the missing parent is the father. Despite the fact that methods exist for analysis where one parent is missing, many family-based studies are based on the collection or analysis of complete trios only. However this selection process might potentially introduce bias, particularly for studies of behavioural phenotypes like ADHD because the phenotype of proband or parents might influence family stability and therefore complete parental ascertainment. We set out to examine whether children with ADHD and for whom DNA samples from fathers were missing ('duos') differed phenotypically from children for whom genotype information was available from both parents ('trios'). Children from duos showed a significantly higher frequency of DMS-IV ADHD-combined type, significantly more co-morbid conduct disorder and conduct disorder symptoms, and a trend for higher total ADHD symptom scores. Excluding duos from sample collection and analysis may result in systematic bias. If comorbid conduct disorder and ADHD-combined type index increased genetic liability, exclusion of duos could further reduce the power of the TDT (and similar tests) to detect susceptibility genes for ADHD, or replicate effects detected by case-control analysis.