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The protozoan parasite Trypanosoma bruceievades clearance by the host immune system through antigenic variation of its dense variant surface glycoprotein (VSG) coat, periodically ‘switching’ expression of the VSG using a large genomic repertoire of VSG-encoding genes1, 2, 3, 4, 5–6. Recent studies of antigenic variation in vivo have focused near exclusively on parasites in the bloodstream6, 7–8, but research has shown that many, if not most, parasites reside in the interstitial spaces of tissues9, 10, 11, 12–13. We sought to explore the dynamics of antigenic variation in extravascular parasite populations using VSG-seq7, a high-throughput sequencing approach for profiling VSGs expressed in populations of T. brucei. Here we show that tissues, not the blood, are the primary reservoir of antigenic diversity during both needle- and tsetse bite-initiated T. bruceiinfections, with more than 75% of VSGs found exclusively within extravascular spaces. We found that this increased diversity is correlated with slower parasite clearance in tissue spaces. Together, these data support a model in which the slower immune response in extravascular spaces provides more time to generate the antigenic diversity needed to maintain a chronic infection. Our findings reveal the important role that extravascular spaces can have in pathogen diversification.

The increasing analytical speed of mass-spectrometry imaging (MSI) has led to growing interest in the medical field. Acute kidney injury is a severe disease with high morbidity and mortality. No reliable cut-offs are known to estimate the severity of acute kidney injury. Thus, there is a need for new tools to rapidly and accurately assess acute ischemia, which is of clinical importance in intensive care and in kidney transplantation. We investigated the value of MSI to assess acute ischemic kidney tissue in a porcine model. A perfusion model was developed where paired kidneys received warm (severe) or cold (minor) ischemia (n= 8 per group). First, ischemic tissue damage was systematically assessed by two blinded pathologists. Second, MALDI-MSI of kidney tissues was performed to study the spatial distributions and compositions of lipids in the tissues. Histopathological examination revealed no significant difference between kidneys, whereas MALDI-MSI was capable of a detailed discrimination of severe and mild ischemia by differential expression of characteristic lipid-degradation products throughout the tissue within 2 h. In particular, lysolipids, including lysocardiolipins, lysophosphatidylcholines, and lysophosphatidylinositol, were dramatically elevated after severe ischemia. This study demonstrates the significant potential of MSI to differentiate and identify molecular patterns of early ischemic injury in a clinically acceptable time frame. The observed changes highlight the underlying biochemical processes of acute ischemic kidney injury and provide a molecular classification tool that can be deployed in assessment of acute ischemic kidney injury.

Many evolutionarily distant pathogenic organisms have evolved similar survival strategies to evade the immune responses of their hosts. These include antigenic variation, through which an infecting organism prevents clearance by periodically altering the identity of proteins that are visible to the immune system of the host1. Antigenic variation requires large reservoirs of immunologically diverse antigen genes, which are often generated through homologous recombination, as well as mechanisms to ensure the expression of one or very few antigens at any given time. Both homologous recombination and gene expression are affected by three-dimensional genome architecture and local DNA accessibility2,3. Factors that link three-dimensional genome architecture, local chromatin conformation and antigenic variation have, to our knowledge, not yet been identified in any organism. One of the major obstacles to studying the role of genome architecture in antigenic variation has been the highly repetitive nature and heterozygosity of antigen-gene arrays, which has precluded complete genome assembly in many pathogens. Here we report the de novo haplotype-specific assembly and scaffolding of the long antigen-gene arrays of the model protozoan parasite Trypanosoma brucei, using long-read sequencing technology and conserved features of chromosome folding4. Genome-wide chromosome conformation capture (Hi-C) reveals a distinct partitioning of the genome, with antigen-encoding subtelomeric regions that are folded into distinct, highly compact compartments. In addition, we performed a range of analyses—Hi-C, fluorescence in situ hybridization, assays for transposase-accessible chromatin using sequencing and single-cell RNA sequencing—that showed that deletion of the histone variants H3.V and H4.V increases antigen-gene clustering, DNA accessibility across sites of antigen expression and switching of the expressed antigen isoform, via homologous recombination. Our analyses identify histone variants as a molecular link between global genome architecture, local chromatin conformation and antigenic variation.

Continuous Flight Auger (CFA) and drilled displacement (DD) piles in the San Francisco (California, USA) area are typically designed using a combination of side- and end resistances. For moderately-sized buildings, these piles are typically 50 to 100 ft (about 15 to 30 m) in length and often bear in Pleistocene epoch alluvium consisting primarily of clay with interbedded sand seams. It can be unconservative to rely upon the higher consistency sand seams because their depth, thickness, and consistency can vary dramatically over short distances. A more robust design approach assigns an end resistance based on the strength of the clay. The fully mobilised end resistance from fifteen (15) high quality axial compression loading tests performed on cast-in-place piles are compared to the average net cone resistance for one diameter below the pile tip. The comparison suggests that direct estimation of the end resistance using local load testing data will result in higher end resistances than will the conventional bearing factor of 9 times the estimated undrained shear strength derived from the cone penetration test.

The nuclear pore complex (NPC) is a macromolecular assembly embedded within the nuclear envelope that mediates bidirectional exchange of material between the nucleus and cytoplasm. Our recent work on the yeast NPC has revealed a simple modularity in its architecture and suggested a common evolutionary origin of the NPC and vesicle coating complexes in a progenitor protocoatomer. However, detailed compositional and structural information is currently only available for vertebrate and yeast NPCs, which are evolutionarily closely related. Hence our understanding of NPC composition in a full evolutionary context is sparse. Moreover despite the ubiquitous nature of the NPC, sequence searches in distant taxa have identified surprisingly few NPC components, suggesting that much of the NPC may not be conserved. Thus, to gain a broad perspective on the origins and evolution of the NPC, we performed proteomics analyses of NPC-containing fractions from a divergent eukaryote (Trypanosoma brucei) and obtained a comprehensive inventory of its nucleoporins. Strikingly trypanosome nucleoporins clearly share with metazoa and yeast their fold type, domain organization, composition, and modularity. Overall these data provide conclusive evidence that the majority of NPC architecture is indeed conserved throughout the Eukaryota and was already established in the last common eukaryotic ancestor. These findings strongly support the hypothesis that NPCs share a common ancestry with vesicle coating complexes and that both were established very early in eukaryotic evolution.

Human placenta insulin receptor was purified 11,000-fold to near homogeneity using DEAE-cellulose chromatography and affinity chromatography on insulin-Sepharose. Approximately 200 to 300 micrograms of purified receptor were obtained from a single placenta. In solution, the native receptor is a complex (Mr = 440,000) of an acidic, multi-subunit protein with a Mr of 350,000 and bound detergent accounting for the remainder of the mass. The receptor protein is asymmetric (f/f0 = 1.4) and consists of a single Coomassie blue staining polypeptide of Mr = 135,000. In addition to the 135,000-dalton polypeptide, two smaller polypeptides of Mr = 45,000 and 90,000 were observed upon autoradiography of 125I-labeled receptor subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These two smaller polypeptides did not stain with Coomassie blue but migrated with native receptor activity on isoelectric focusing gels and were coimmunoprecipitated with the 135,000-dalton polypeptide by anti-insulin receptor antibody. The 135,000-dalton subunit was specifically labeled by 125I-insulin using the bifunctional cross-linking reagent disuccinimidyl suberate (P. F. Pilch, and M. P. Czech, (1979) J. Biol. Chem. 254, 3375-3381), suggesting that this component contains the insulin binding domain.

Abstract: Colonogastric fistula, more commonly called “gastrocolic,” is a rare complication of Crohn's colitis. The 17th incidence of this fistula is reported. Fecal halitosis is a prominent symptom. Barium enema is the most accurate diagnostic tool. Colonoscopy plays a role in delineating surgical therapy. The stomach resection is described. Because of its pathogenesis, the authors prefer to call this “colonogastric” fistula, rather than gastrocolic fistula.

Insulin-binding activity was measured in hepatocyte suspensions and liver membrane preparations from newborn mice homozygous for a perinatal-lethal deletion at and around the albino locus in chromosome 7. Cell suspensions and membrane preparations from the mutant mice exhibited only 20-25% of the specific hormone-binding activity observed in comparable preparations from their homozygous normal and heterozygous littermates. The decrease in insulin-binding activity appears to be attributable to a decrease in the number of insulin receptor sites per cell rather than to a change in receptor affinity. Gene sequences deleted at and around the albino locus are therefore instrumental in the regulation of insulin receptor concentration rather than in coding for the insulin receptor itself. The results of the present studies extend the identification of the regulatory functions exerted by the genes around the albino locus of the mouse.

We present a case of a 78-year-old woman with abdominal-wall muscle paralysis following cutaneous herpes zoster in the T12-L1 dermatomes. An EMG confirmed paralysis, and a CT scan ruled out fascial defect. The paralysis had completely resolved 1 year later. A review of the literature regarding these unusual sequelae of herpes zoster is presented.

Percutaneous endoscopic gastrostomy (PEG) has become the procedure of choice for long-term enteral feeding. Complications are generally infrequent and often avoidable. We describe an unusual case in which a PEG tube bumper caused subcutaneous perforation of an ileostomy. After conservative treatment proved unsuccessful, revision of the ileostomy via a peristomal incision was performed, with good result. Caution must be exercised before considering the severance of a PEG tube at the skin, especially in patients with an ileostomy.

We have observed the signatures of quantum trajectories while generating harmonics in metal plasmas by using a high pulse repetition rate (1-kHz) Ti:sapphire laser source. We present how focusing conditions, laser intensity, plasma concentration, and the chirp of laser radiation influence the observation of separated quantum paths. Our studies demonstrate the clear fingerprints of the separated quantum paths in the case of an ionized medium. [ABSTRACT FROM AUTHOR]