G-quadruplex DNA structure is a positive regulator of MYC transcription.

DNA structure can regulate genome function. Four-stranded DNA G-quadruplex (G4) structures have been implicated in transcriptional regulation; however, previous studies have not directly addressed the role of an individual G4 within its endogenous cellular context. Using CRISPR to genetically abrogate endogenous G4 structure folding, we directly interrogate the G4 found within the upstream regulatory region of the critical human MYC oncogene. G4 loss leads to suppression of MYC transcription from the P1 promoter that is mediated by the deposition of a de novo nucleosome alongside alterations in RNA polymerase recruitment. We also show that replacement of the endogenous MYC G4 with a different G4 structure from the KRAS oncogene restores G4 folding and MYC transcription. Moreover, we demonstrate that the MYC G4 structure itself, rather than its sequence, recruits transcription factors and histone modifiers. Overall, our work establishes that G4 structures are important features of transcriptional regulation that coordinate recruitment of key chromatin proteins and the transcriptional machinery through interactions with DNA secondary structure, rather than primary sequence.

Comprehensive assessment of tissue and serum parameters of bone metabolism in a series of orthopaedic patients.

Bone diseases represent an increasing health burden worldwide, and basic research remains necessary to better understand the complexity of these pathologies and to improve and expand existing prevention and treatment approaches. In the present study, 216 bone samples from the caput femoris and collum femoris of 108 patients with degenerative or dysplastic coxarthrosis, hip fracture, or osteonecrosis were evaluated for the proportion of trabecular bone (TB) and expression of parathyroid hormone (PTH) type 1 receptor (PTH1R), osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL). Serum levels of PTH, OPG, soluble RANKL (sRANKL), alkaline phosphatase (AP), osteocalcin, total procollagen type-1 intact N-terminal propeptide (TP1NP), tartrate-resistant acid phosphatase type 5b (TRAP5b), sclerostin, and C-telopeptide of type-1 collagen (ICTP) were also determined. Age was positively correlated with serum levels of PTH, OPG, and sclerostin but negatively associated with TB and sRANKL. Women exhibited less TB, lower sclerostin and ICTP, and higher TRAP5b. Impaired kidney function was associated with shorter bone decalcification time, less TB, lower sRANKL, and higher serum PTH, OPG, and sclerostin. Furthermore, correlations were observed between bone PTH1R and OPG expression and between serum PTH, OPG, and AP. There were also positive correlations between serum OPG and TP1NP; serum OPG and sclerostin; serum AP, osteocalcin, and TRAP5b; and serum sclerostin and ICTP. Serum OPG was negatively associated with sRANKL. In summary, clear relationships between specific bone metabolism markers were observed, and distinct influences of age, sex, and kidney function, thus underscoring their suitability as diagnostic or prognostic markers.

[Very severe thrombotic thrombocytopenic purpura (TTP) after H1N1 vaccination]. / Schwerste thrombotisch-thrombozytopenische Purpura (TTP) nach H1N1-Vakzinierung.

BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) is a severe disease with microthrombi in various organs. The idopathic subtype is characterized by reduced ADAMTS13 activity mediated via autoantibodies against this protease. Induction of autoantibodies mechanistically is incompletely understood, but certain drugs can induce anti-ADAMTS13 antibodies through hapten mechanisms. CASE REPORT: A 56-year-old man was admitted from an external hospital because of a rapidly worsening general condition, hemolytic anemia (hemoglobin 4.17 mmol/l, hematocrit 0.19), and thrombocytopenia (22 Gpt/l) for unknown reasons. Additionally, he was found to have an elevated lactate dehydrogenase (45.37 µmol/l/s). 13 days before hospitalization he had received vaccination against H1N1. Laboratory tests revealed an increased total bilirubin (126 µmol/l), and a decreased haptoglobin level (< 0.08 g/l). The blood smear showed 24% fragmentocytes. Direct and indirect Coombs test were negative. TPP was diagnosed based on the clinical presentation and the detection of ADAMTS13 antibodies. Despite daily plasma exchange via plasmapheresis and administration of corticosteroids, there was no significant rise in platelet counts. Immunosuppression with a total of four weekly doses of rituximab (375 mg/m(2) body surface area) was added. Over the next 5 weeks, the platelet count very slowly rose. After a total of 46 sessions, plasmapheresis was ended with complete remission of the disease. CONCLUSION: This report emphasizes the immunologic susceptibility of TTP, and suggests the potential, but not proven role of H1N1 vaccination in the pathogenesis of TTP, because no serum before vaccination was available. Severe autoantibody TTP can be successfully treated by administering rituximab in addition to standard treatment with plasmapheresis and corticosteroids.

Parenchymal and pleural findings in pulmonary embolism visualized by multi-channel detector computed tomography.

BACKGROUND: A normal computed tomography (CT) scan of the pulmonary arteries in the presence of parenchymal and pleural abnormalities may indicate a false-negative diagnosis of pulmonary embolism (PE). Multi-channel detector CT (MDCT) with thinner collimation may improve the detection of small peripheral PEs causing such abnormalities. PURPOSE: To investigate parenchymal and pleural findings visualized by contrast-enhanced MDCT in patients with and without PE, and to identify possible predictors of PE. MATERIAL AND METHODS: 129 patients with clinical signs of PE were included. In all patients an iopromide-enhanced 64-MDCT (64x0.625 mm collimation, pitch 1.375, overlapping reconstruction with a slice thickness of 0.625 mm, increment of overlapping slice reconstruction 0.43) was performed within 24 h after the onset of the symptoms. RESULTS: MDCT detected PE in 45 of the 129 patients (35%). PE and parenchymal/pleural findings were localized predominantly within the lower lobes. Wedge-shaped opacities were significantly associated with PE (OR =3.00; 95% confidence interval 1.13-7.91). Vascular signs were only visualized in patients with PE. Nodules, consolidations, atelectasis, or effusions were not predictive of PE. CONCLUSION: The present MDCT study verified that parenchymal and pleural findings can be found in patients with or without PE. Wedge-shaped opacities and vascular signs were significantly associated with PE and therefore can be potential predictors of PE.

Linear stability of an alternating-magnetic-field-driven flow in a spinning cylindrical container.

We present a numerical analysis of free-surface liquid metal flow and its three-dimensional linear stability. The flow is driven by an alternating magnetic field in a spinning cylindrical container. The electromagnetic and hydrodynamic fields are fully coupled via the shape of the liquid free surface. The hydrodynamic equations are solved by a spectral collocation method, and the alternating magnetic field distribution is found by a boundary-integral method. The flow stability is analyzed for various magnetohydrodynamic interaction parameters and Ekman numbers assuming a flat free surface. We find that only a sufficiently fast spinning suppresses and stabilizes the flow, but a moderate spinning can significantly destabilize it.