Both in children and adults, acute leukemia may present with extremely high blast counts; a phenomenon known as hyperleukocytosis. Respiratory failure, intracranial bleeding, and severe metabolic abnormalities frequently occur in acute hyperleukocytic leukemias (AHLs) and are the primary determinants of the high early mortality (20% to 40%) observed. The process leading to these complications has long been known as leukostasis, but the biological mechanisms underlying its development and progression have remained unclear. Traditionally, leukostasis has been attributed to overcrowding of leukemic blasts in the microcirculation, and its treatment has focused on prompt leukocytoreduction. However, it is becoming increasingly evident that leukostasis results from the adhesive interactions between leukemic blasts and the endothelium; a mechanism that none of the current therapies directly addresses. The endothelial damage associated with leukostasis is likely to be mediated by cytokines released in situ and by subsequent migration of leukemic blasts in the perivascular space. The adhesion molecules displayed by the leukemic blasts and their chemotactic response to the cytokines in the vascular microenvironment are probably more important in causing leukostasis than the cell number. This may explain why leukostasis may develop in some patients with AHL and not in others, and why some patients with acute leukemia without hyperleukocytosis (<50,000 blasts/mm3) develop leukostasis and respond to leukocytoreduction. Leukapheresis effectively reduces the blast count in many patients with AHL and is routinely used for immediate leukocytoreduction. However, the most appropriate use of leukapheresis in acute leukemia remains unclear, and the procedure may not prevent early death more efficiently than fluid therapy, hydroxyurea, and prompt induction chemotherapy. The use of cranial irradiation remains very controversial and is not generally recommended. The identification of the adhesion molecules, soluble cytokines, and chemotactic ligand‐receptor pairs mediating endothelial cell damage in AHL should become a priority if better outcomes are desired.

The diagnosis of glomerulonephritis flares in systemic lupus erythematosus (SLE) is usually based on whether the magnitude of proteinuria has changed. Our study tests two methods to assess proteinuric change: protein/creatinine (P/C) ratios of intended 24-h urine collections or that of spot urine samples. Sixty-four patients with glomerulonephritis due to SLE followed in the Ohio SLE Study provided bimonthly paired spot and intended 24-h urine collections. Completeness of each collection was estimated as the ratio of the measured creatinine to the expected creatinine based upon Cockroft-Gault. Intended 24-h urine collections with measured/expected creatinine ratios between 0.5 and 0.9 (237 samples overall) showed ratios that were not significantly different from ratios of complete 24-h urine collections with ratios of 0.9-1.1 (159 samples). To compare spot and 24 h P/C ratios, we randomly selected pairs of samples with measured/expected ratios above 0.75. Consistent with previous studies, spot and 24-h urine P/C ratios showed good correlation over the range of values as well as reasonably strong concordance. Over the range of most SLE glomerulonephritis flares, however, correlation was present but concordance was poor. Our work suggests that the use of spot urine P/C ratios will yield more false-positive and -negative diagnoses of glomerulonephritis flares in patients with SLE than the ratio in 24-h urines.

The Synthetic Biology Open Language (SBOL) is a standard that enables collaborative engineering of biological systems across different institutions and tools. SBOL is developed through careful consideration of recent synthetic biology trends, real use cases, and consensus among leading researchers in the field and members of commercial biotechnology enterprises. We demonstrate and discuss how a set of SBOL-enabled software tools can form an integrated, cross-organizational workflow to recapitulate the design of one of the largest published genetic circuits to date, a 4-input AND sensor. This design encompasses the structural components of the system, such as its DNA, RNA, small molecules, and proteins, as well as the interactions between these components that determine the system's behavior/function. The demonstrated workflow and resulting circuit design illustrate the utility of SBOL 2.0 in automating the exchange of structural and functional specifications for genetic parts, devices, and the biological systems in which they operate.

To cite this article: Jin M, Cataland S, Bissell M, Wu HM. A rapid test for the diagnosis of thrombotic thrombocytopenic purpura using surface Summary. Background: Thrombotic thrombocytopenic purpura (TTP), a life-threatening thrombotic microangiopathy, requires immediate diagnosis and plasma exchange therapy. Development of TTP is related to functional deficiency of ADAMTS-13 protease that leads to the accumulation of ultra large von Willebrand factor (VWF) and subsequent platelet thrombosis. Currently no clinical test is available for the rapid detection of ADAMTS-13 activity. Objectives: The goal is to devise a novel method to rapidly detect functional activity of ADAMTS-13 and improve clinical outcome. Methods and results: A recombinant VWF substrate containing the ADAM-TS-13 cleavage site and a 6X Histidine tag was cleaved by ADAMTS-13 in a dose-dependent manner, generating approximately 7739 Da peptide containing a 6X Histidine tag. This cleaved peptide, bound to an IMAC/Nickel ProteinChip, was quantified using Surface Enhanced Laser Desorption/Ionization Time-of-flight Mass Spectrometry (SELDI-TOF-MS). The assay is capable of quantifying ADAMTS-13 activity as low as 2.5% in plasma within 4 h. When the cleaved peptide was quantified as a ratio of an internal control peptide, the test displayed good reproducibility, with an average interassay coefficient of variation (CV) of < 33%. Further validation revealed a mean ADAMTS-13 activity of 92.5% ± 16.6% in 39 healthy donors. Sixteen patients with idiopathic TTP displayed mean ADAMTS-13 activity of 1.73% ± 3.62%. Further utility of this novel method includes determining the inhibitory titer of ADAMTS-13 antibody in cases of acquired TTP. Conclusions: We have devised a novel SELDI-TOF-MS assay that offers a rapid, cost-effective, and functionally relevant test for timely diagnosis and management of TTP.

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