Conformational equilibria in monomeric alpha-synuclein at the single molecule level

Natively unstructured proteins defy the classical "one sequence-one structure" paradigm of protein science. Monomers of these proteins in pathological conditions can aggregate in the cell, a process that underlies socially relevant neurodegenerative diseases such as Alzheimer and Parkinson. A full comprehension of the formation and structure of the so-called misfolded intermediates from which the aggregated states ensue is still lacking. We characterized the folding and the conformational diversity of alpha-synuclein (aSyn), a natively unstructured protein involved in Parkinson disease, by mechanically stretching single molecules of this protein and recording their mechanical properties. These experiments permitted us to directly observe directly and quantify three main classes of conformations that, under in vitro physiological conditions, exist simultaneously in the aSyn sample, including disordered and "beta-like" structures. We found that this class of "beta-like" structures is directly related to aSyn aggregation. In fact, their relative abundance increases drastically in three different conditions known to promote the formation of aSyn fibrils: the presence of Cu2+, the occurrence of the pathogenic A30P mutation, and high ionic strength. We expect that a critical concentration of aSyn with a "beta-like" structure must be reached to trigger fibril formation. This critical concentration is therefore controlled by a chemical equilibrium. Novel pharmacological strategies can now be tailored to act upstream, before the aggregation process ensues, by targeting this equilibrium. To this end, Single Molecule Force Spectroscopy can be an effective tool to tailor and test new pharmacological agents.Comment: 37 pages, 9 figures (including supplementary material

Long-term results of the HD2000 trial comparing ABVD versus BEACOPP versus COPP-EBV-CAD in untreated patients with advanced hodgkin lymphoma: A study by fondazione Italiana Linfomi

Purpose The randomized HD2000 trial compared six cycles of ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine), four escalated plus two standard cycles of BEACOPP (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone), and six cycles of COPPEBV- CAD (cyclophosphamide, lomustine, vindesine, melphalan, prednisone, epidoxorubicin, vincristine, procarbazine, vinblastine, and bleomycin; CEC) in patients with advanced-stage Hodgkin lymphoma. After a median follow-up of 42 months, patients who received BEACOPP were reported to have experienced better progression-free survival (PFS) but not better overall survival (OS) results than those receiving ABVD. Wehere report a post hoc analysis of this trial after a median follow-up of 10 years. Patients and Methods Three hundred seven patients were enrolled, 295 of whom were evaluable. At the time of our analysis, the median follow-up for the entire group was 120 months (range, 4 to 169 months). Results The 10-year PFS results for the ABVD, BEACOPP, and CEC arms were 69%, 75%, and 76%, respectively; corresponding OS results were 85%, 84%, and 86%. Overall, 13 second malignancies were reported: one in the ABVD arm and six each in the BEACOPP and CEC arms. The cumulative risk of developing secondmalignancies at 10 years was 0.9%, 6.6%, and 6% with ABVD, BEACOPP, and CEC, respectively; the risk with either BEACOPP or CEC was significantly higher than that reported with ABVD (P = .027 and .02, respectively). Conclusion With these mature results, we confirm that patients with advanced Hodgkin lymphoma have similar OS results when treated with ABVD, BEACOPP, or CEC. However, with longer follow-up, we were not able to confirm the superiority of BEACOPP over ABVD in terms of PFS, mainly because of higher mortality rates resulting from second malignancies observed after treatment with BEACOPP and CEC

Diagnosis and Treatment of Chronic Neuropathic and Mixed Pain in Children and Adolescents: Results of a Survey Study amongst Practitioners

Validated diagnostic tools to diagnose chronic neuropathic and mixed pain in children are missing. Therapeutic options are often derived from therapeutics for adults. To investigate the international practice amongst practitioners for the diagnosis and treatment of chronic, neuropathic pain in children and adolescents, we performed a survey study among members of learned societies or groups whose members are known to treat pediatric pain. The survey included questions concerning practitioners and practice characteristics, assessment and diagnosis, treatment and medication. We analyzed 117 returned questionnaires, of which 41 (35%) were fully completed and 76 (65%) were partially completed. Most respondents based the diagnosis of neuropathic pain on physical examination (68 (58.1%)), patient history (67 (57.3%)), and underlying disease (59 (50.4%)) combined. Gabapentin, amitriptyline, and pregabalin were the first-choice treatments for moderate neuropathic pain. Tramadol, ibuprofen, amitriptyline, and paracetamol were the first-choice treatments for moderate mixed pain. Consensus on the diagnostic process of neuropathic pain in children and adolescents is lacking. Drug treatment varies widely for moderate, severe neuropathic, and mixed pain. Hence, diagnostic tools and therapy need to be harmonized and validated for use in children