The mechanism of chronic rejection of transplanted human kidneys is unknown. An understanding of this process is important because, chronic rejection ultimately leads to loss of the kidney allograft in most transplants. One feature of chronic rejection is the infiltration of ectopic B-cell clusters that are clonal into the transplanted kidney. We now show that the antibodies produced by these B-cells react strongly with the core carbohydrate region of LPS. Since LPS is a costimulatory immunogen that can react with both the B-cell receptor (BCR) and the Toll-like receptor 4 (TLR4), these results suggest a mechanism for the selective pressure that leads to clonality of these B-cell clusters and opens the possibility that infection and the attendant exposure to LPS plays a role in the chronic rejection of human kidney transplants. If confirmed by clinical studies, these results suggest that treating patients with signs of chronic rejection with antibiotics may improve kidney allograft survival.

Background

The diagnosis of blunt abdominal trauma can be challenging and resource intensive. Observation with serial clinical assessments plays a major role in the evaluation of these patients, but the time required for intra-abdominal injury to become clinically apparent is unknown. The purpose of this study was to determine the amount of time required for an intra-abdominal injury to become clinically apparent after blunt abdominal trauma via physical examination or commonly followed clinical values.

Methods

A retrospective review of patients who sustained blunt trauma resulting in intra-abdominal injury between June 2010 and June 2012 at a Level 1 academic trauma center was performed. Patient demographics, injuries, and the amount of time from emergency department admission to sign or symptom development and subsequent diagnosis were recorded. All diagnoses were made by computed tomography or at the time of surgery. Patient transfers from other hospitals were excluded.

Results

Of 3,574 blunt trauma patients admitted to the hospital, 285 (8%) experienced intra-abdominal injuries. The mean (SD) age was 36 (17) years, the majority were male (194 patients, 68%) and the mean (SD) Injury Severity Score (ISS) was 21 (14). The mean (SD) time from admission to diagnosis via computed tomography or surgery was 74 (55) minutes. Eighty patients (28%) required either surgery (78 patients, 17%) or radiographic embolization (2 patients, 0.7%) for their injury. All patients who required intervention demonstrated a sign or symptom of their intra-abdominal injury within 60 minutes of arrival, although two patients were intervened upon in a delayed fashion. All patients with a blunt intra-abdominal injury manifested a clinical sign or symptom of their intra-abdominal injury, resulting in their diagnosis within 8 hours 25 minutes of arrival to the hospital.

Conclusion

All diagnosed intra-abdominal injuries from blunt trauma manifested clinical signs or symptoms that could prompt imaging or intervention, leading to their diagnosis within 8 hours 25 minutes of arrival to the hospital. All patients who required an intervention for their injury manifested a sign or symptom of their injury within 60 minutes of arrival.

Level of evidence

Therapeutic study, level IV. Epidemiologic study, level III.

Peatlands are crucial sinks for atmospheric carbon but are critically threatened due to warming climates. Sphagnum (peat moss) species are keystone members of peatland communities where they actively engineer hyperacidic conditions, which improves their competitive advantage and accelerates ecosystem-level carbon sequestration. To dissect the molecular and physiological sources of this unique biology, we generated chromosome-scale genomes of two Sphagnum species: S. divinum and S. angustifolium. Sphagnum genomes show no gene colinearity with any other reference genome to date, demonstrating that Sphagnum represents an unsampled lineage of land plant evolution. The genomes also revealed an average recombination rate an order of magnitude higher than vascular land plants and short putative U/V sex chromosomes. These newly described sex chromosomes interact with autosomal loci that significantly impact growth across diverse pH conditions. This discovery demonstrates that the ability of Sphagnum to sequester carbon in acidic peat bogs is mediated by interactions between sex, autosomes and environment.

Polyploidy results from whole-genome duplication and is a unique form of heritable variation with pronounced evolutionary implications. Different ploidy levels, or cytotypes, can exist within a single species, and such systems provide an opportunity to assess how ploidy variation alters phenotypic novelty, adaptability, and fitness, which can, in turn, drive the development of unique ecological niches that promote the coexistence of multiple cytotypes. Switchgrass, Panicum virgatum, is a widespread, perennial C4 grass in North America with multiple naturally occurring cytotypes, primarily tetraploids (4×) and octoploids (8×). Using a combination of genomic, quantitative genetic, landscape, and niche modeling approaches, we detect divergent levels of genetic admixture, evidence of niche differentiation, and differential environmental sensitivity between switchgrass cytotypes. Taken together, these findings support a generalist (8×)–specialist (4×) trade-off. Our results indicate that the 8× represent a unique combination of genetic variation that has allowed the expansion of switchgrass’ ecological niche and thus putatively represents a valuable breeding resource.

For nearly 50 years, the vision of using single molecules in circuits has been seen as providing the ultimate miniaturization of electronic chips. An advanced example of such a molecular electronics chip is presented here, with the important distinction that the molecular circuit elements play the role of general-purpose single-molecule sensors. The device consists of a semiconductor chip with a scalable array architecture. Each array element contains a synthetic molecular wire assembled to span nanoelectrodes in a current monitoring circuit. A central conjugation site is used to attach a single probe molecule that defines the target of the sensor. The chip digitizes the resulting picoamp-scale current-versus-time readout from each sensor element of the array at a rate of 1,000 frames per second. This provides detailed electrical signatures of the single-molecule interactions between the probe and targets present in a solution-phase test sample. This platform is used to measure the interaction kinetics of single molecules, without the use of labels, in a massively parallel fashion. To demonstrate broad applicability, examples are shown for probe molecule binding, including DNA oligos, aptamers, antibodies, and antigens, and the activity of enzymes relevant to diagnostics and sequencing, including a CRISPR/Cas enzyme binding a target DNA, and a DNA polymerase enzyme incorporating nucleotides as it copies a DNA template. All of these applications are accomplished with high sensitivity and resolution, on a manufacturable, scalable, all-electronic semiconductor chip device, thereby bringing the power of modern chips to these diverse areas of biosensing.