AIMS: (i) Evaluation of delayed time to blood culture extraction by the Sepsityper kit and impact of shipping pellets off‐site for MALDI‐TOF MS analysis. (ii) Comparison of Sepsityper and ...laboratory‐developed extraction methods from a literature review. METHODS AND RESULTS: Using two blood culture systems (BD BACTEC and VersaTREK), we extracted 411 positive blood cultures using the Sepsityper kit to mimic a potential protocol for institutions without a MALDI‐TOF MS. Extracted pellets were shipped and analysed on the Bruker UltraflexIII. Successful extraction of 358 (87·1%) samples was determined by the presence of detectable proteins. MALDI‐TOF MS correctly identified 332 (80·8%) samples. CONCLUSIONS: Delayed time to extraction did not affect Sepsityper extraction or MALDI‐TOF MS accuracy. The extracted pellets remain stable and provide accurate results by MALDI‐TOF MS when shipped at room temperature to off‐site reference laboratories. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study to show that institutions without a MALDI‐TOF MS can take advantage of this innovative technology by shipping a volume of blood to an off‐site laboratory for extraction and MALDI‐TOF MS analysis. We also performed a literature review to compare various extraction methods.
Widespread and persistent organochlorine (OC) contaminants, such as polychlorinated biphenyls (PCBs) and pesticides, are known to have broad-ranging toxicities in wildlife. In this study we ...investigated, for the first time, their possible health effects on loggerhead sea turtles (Caretta caretta). Nonlethal fat biopsies and blood samples were collected from live turtles for OC contaminant analysis, and concentrations were compared with clinical health assessment data, including hematology, plasma chemistry, and body condition. Concentrations of total PCBs (ΣPCBs), ΣDDTs, Σchlordanes, dieldrin, and mirex were determined in 44 fat biopsies and 48 blood samples. Blood concentrations of Σchlordanes were negatively correlated with red blood cell counts, hemoglobin, and hematocrit, indicative of anemia. Positive correlations were observed between most classes of OC contaminants and white blood cell counts and between mirex and ΣTCDD-like PCB concentrations and the heterophil:lymphocyte ratio, suggesting modulation of the immune system. All classes of OCs in the blood except dieldrin were correlated positively with aspartate aminotransferase (AST) activity, indicating possible hepatocellular damage. Mirex and ΣTCDD-like PCB blood concentrations were negatively correlated with alkaline phosphatase (ALP) activity. Significant correlations to levels of certain OC contaminant classes also suggested possible alteration of protein (↑ blood urea nitrogen, ↓ albumin:globulin ratio), carbohydrate (↓ glucose), and ion (↑ sodium, ↓ magnesium) regulation. These correlations suggest that OC contaminants may be affecting the health of loggerhead sea turtles even though sea turtles accumulate lower concentrations of OCs compared with other wildlife.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The performance characteristics of HIV rapid diagnostic tests (RDTs) vary by test and by population. We assessed five commercial RDTs in Uganda where all but one RDT (Determine; Abbott Laboratories, ...Germany) performed close to manufacturer's expectations. Determine had low specificity (85.2%, positive predictive value 67.3%) due to false-positive results with weak-positive bands. Properly trained staff, good quality control programmes and validation of RDTs with laboratories having confirmatory testing capacity may be warranted to assure accuracy in each setting.
Human trichomoniasis is the most common non-viral sexually transmitted disease, yet immune responses are not well studied.
Since the Trichomonas vaginalis lipophosphoglycan (TvLPG) is an important ...virulence factor, a bank of eight monoclonal antibodies was generated to define the antigen in clinical isolates. The TvLPG-specific antibody response of women who were culture positive (n=33) or negative (n=33) for T vaginalis infection was determined by isotype-specific ELISA.
The bank of monoclonal antibodies reacted with conserved surface TvLPG epitopes in 27 isolates from pregnant women at their first prenatal visit. Conserved TvLPG epitopes were shown to be surface exposed by immunofluorescence. Sera collected from the same patients at the same time were assayed for specific antibodies. Serum and vaginal secretions from 33 T vaginalis-positive women had statistically higher IgG anti-TvLPG levels than age-matched and race-matched negative controls in the same clinical study (p<0.01). Vaginal IgA anti-TvLPG levels of the women with trichomoniasis were almost significantly higher than controls (p=0.055). Infected women with normal pregnancies had significantly higher vaginal IgG anti-TvLPG values than infected women with adverse outcomes of pregnancy.
These antibody responses show that infected women can respond to the conserved TvLPG antigen. Since antibodies to trichomonad surface LPG protect in a bovine model of trichomoniasis, the role of these antibodies in the human disease should be investigated.
Antibodies result from the competition of B cell lineages evolving under selection for improved antigen recognition, a process known as affinity maturation. High-affinity antibodies to pathogens such ...as HIV, influenza, and SARS-CoV-2 are frequently reported to arise from B cells whose receptors, the precursors to antibodies, are encoded by particular immunoglobulin alleles. This raises the possibility that the presence of particular germline alleles in the B cell repertoire is a major determinant of the quality of the antibody response. Alternatively, initial differences in germline alleles’ propensities to form high-affinity receptors might be overcome by chance events during affinity maturation. We first investigate these scenarios in simulations: when germline-encoded fitness differences are large relative to the rate and effect size variation of somatic mutations, the same germline alleles persistently dominate the response of different individuals. In contrast, if germline-encoded advantages can be easily overcome by subsequent mutations, allele usage becomes increasingly divergent over time, a pattern we then observe in mice experimentally infected with influenza virus. We investigated whether affinity maturation might nonetheless strongly select for particular amino acid motifs across diverse genetic backgrounds, but we found no evidence of convergence to similar CDR3 sequences or amino acid substitutions. These results suggest that although germline-encoded specificities can lead to similar immune responses between individuals, diverse evolutionary routes to high affinity limit the genetic predictability of responses to infection and vaccination.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We have produced Bose-Einstein condensates in a ring-shaped magnetic waveguide. The few-millimeter diameter, nonzero-bias ring is formed from a time-averaged quadrupole ring. Condensates that ...propagate around the ring make several revolutions within the time it takes for them to expand to fill the ring. The ring shape is ideally suited for studies of vorticity in a multiply connected geometry and is promising as a rotation sensor.
A quantum dipolar spin liquid Yao, N. Y.; Zaletel, M. P.; Stamper-Kurn, D. M. ...
Nature physics,
04/2018, Letnik:
14, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Quantum spin liquids are a class of magnetic ground states reliant on non-local entanglement. Motivated by recent advances in the control of ultracold polar molecules and the development of dipolar ...quantum materials, we show that dipolar interactions between S = 1/2 moments stabilize spin liquids on the triangular and kagome lattices. In the latter case, the moments spontaneously break time-reversal, forming a chiral spin liquid with robust edge modes and emergent semions. We propose a simple route toward synthesizing a dipolar Heisenberg antiferromagnet from lattice-trapped polar molecules using only a single pair of rotational states and a constant electric field.
Dissecting the evolution of memory B cells (MBCs) against SARS-CoV-2 is critical for understanding antibody recall upon secondary exposure. Here, we used single-cell sequencing to profile ...SARS-CoV-2-reactive B cells in 38 COVID-19 patients. Using oligo-tagged antigen baits, we isolated B cells specific to the SARS-CoV-2 spike, nucleoprotein (NP), open reading frame 8 (ORF8), and endemic human coronavirus (HCoV) spike proteins. SARS-CoV-2 spike-specific cells were enriched in the memory compartment of acutely infected and convalescent patients several months post symptom onset. With severe acute infection, substantial populations of endemic HCoV-reactive antibody-secreting cells were identified and possessed highly mutated variable genes, signifying preexisting immunity. Finally, MBCs exhibited pronounced maturation to NP and ORF8 over time, especially in older patients. Monoclonal antibodies against these targets were non-neutralizing and non-protective in vivo. These findings reveal antibody adaptation to non-neutralizing intracellular antigens during infection, emphasizing the importance of vaccination for inducing neutralizing spike-specific MBCs.
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•Simultaneous capture of B cell transcripts, BCR sequence, and specificity in COVID-19•ASCs reactive to HCoV dominate the early response to severe acute infection•MBCs targeting NP and ORF8 adapt over time and are increased in older patients•Anti-NP and ORF8 mAbs given prophylactically in animal infection models do not protect
Dugan et al. use a multi-antigen bait sorting and single-cell sequencing approach to profile B cell immunodominance upon SARS-CoV-2 infection, revealing a dynamic response that evolves toward internal virus proteins over time. Antibodies to internal proteins were non-protective in vivo, highlighting the importance of vaccination for generating spike-dominated immune memory.
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