Heavy-flavour and quarkonium production in the LHC era: from proton-proton to heavy-ion collisions.

This report reviews the study of open heavy-flavour and quarkonium production in high-energy hadronic collisions, as tools to investigate fundamental aspects of Quantum Chromodynamics, from the proton and nucleus structure at high energy to deconfinement and the properties of the Quark-Gluon Plasma. Emphasis is given to the lessons learnt from LHC Run 1 results, which are reviewed in a global picture with the results from SPS and RHIC at lower energies, as well as to the questions to be addressed in the future. The report covers heavy flavour and quarkonium production in proton-proton, proton-nucleus and nucleus-nucleus collisions. This includes discussion of the effects of hot and cold strongly interacting matter, quarkonium photoproduction in nucleus-nucleus collisions and perspectives on the study of heavy flavour and quarkonium with upgrades of existing experiments and new experiments. The report results from the activity of the SaporeGravis network of the I3 Hadron Physics programme of the European Union 7[Formula: see text] Framework Programme.

Observation of direct photons in central 158A GeV (208)P(208)b+Pb collisions

A measurement of direct photon production in 208Pb+208Pb collisions at 158A GeV has been carried out in the CERN WA98 experiment. The invariant yield of direct photons in central collisions is extracted as a function of transverse momentum in the interval 0.51.5 GeV/c. The result constitutes the first observation of direct photons in ultrarelativistic heavy-ion collisions. It could be significant for diagnosis of quark-gluon-plasma formation.

Interference in exclusive vector meson production in heavy-Ion collisions

Vector mesons are produced copiously in peripheral relativistic heavy-ion collisions. Virtual photons from one ion can fluctuate into quark-antiquark pairs and scatter from the second ion, emerging as vector mesons. The emitter and target are indistinguishable, so emission from the two ions will interfere. Vector mesons have negative parity so the interference is destructive, reducing the production of mesons with small transverse momentum. The mesons are short lived, and decay before emission from the two ions can overlap. However, the decay-product wave functions overlap and interfere since they are produced in an entangled state, providing an example of the Einstein-Podolsky-Rosen paradox.

Serum tryptase measured with B12 and G5 antibody-based immunoassays in mastocytosis patients and its relation to histamine turnover.

Serum tryptase was measured with the B12 and G5 antibody-based immunoassays in 25 adult patients with mastocytosis and in 18 controls. Twelve patients had uncomplicated cutaneous mastocytosis (urticaria pigmentosa) and 13 had urticaria pigmentosa with systemic symptoms. Tryptase levels were compared with histamine turnover estimated as urinary excretion of the main histamine metabolite tele-methylimidazoleacetic acid. Elevated B12 tryptase levels (> 20 microg/L) were found in most mastocytosis patients, including five of eight patients with only cutaneous manifestations who had a low urinary histamine metabolite excretion. This indicated a higher sensitivity for diagnosing mild mastocytosis on the basis of levels of serum tryptase as opposed to urinary methylimidazoleacetic acid. However, the serum B12 tryptase assay could not differentiate between urticaria pigmentosa patients with and without systemic disease: the measurement of histamine metabolite excretion probably reflects the mast cell burden more accurately. Serum G5 tryptase levels were generally low in both controls and mastocytosis patients.

Radioimmunoassay of human eosinophil cationic protein (ECP) by an improved method. Establishment of normal levels in serum and turnover in vivo.

A radioimmunoassay was developed allowing measurement of the cytotoxic cationic ECP. The assay, which has a total incubation time of 3.5 hr, is a double antibody assay with radiolabelled ECP, covering the concentration range of 2-200 micrograms/l. Performance data show a detection limit of less than 2 micrograms/l and a cross-reactivity with eosinophil protein X (EPX/EDN) of less than 0.06%. The coefficient of variation (%) within the measuring range was, within assay 4.8-10.4, and total 6.6-12.0. The assay is useful for measurement in various body fluids including serum, nasal secretions and bronchoalveolar lavage fluid, and dilution of samples prior to analysis was generally not required. Sera from 100 apparently healthy individuals revealed a geometric mean of 6.0 micrograms ECP/l and a range (95%) of 2.3-15.9 micrograms/l. The elimination rate of ECP, t1/2, in vivo was estimated to be 65 min when ECP was measured in serum. Comparisons between this assay and a method previously described showed that the new method is superior with regard to precision and assay procedure.

Evaluation of mast cell activation (tryptase) in two patients suffering from drug-induced hypotensoid reactions.

Tryptase is predominantly found in mast cells, where it resides in secretory granules, and is released with other mediators during mast cell degranulation. By using a newly developed commercial assay for measurements of tryptase levels we have investigated two cases of suspected drug-induced anaphylaxis. Each patient had a similar clinical presentation, consisting of hypotension and cyanosis after administration of thiopentone and suxamethonium. One of the patients showed a highly elevated serum level of tryptase reaching 26 micrograms/l 30 min after the initial reaction. In addition, slightly elevated levels of specific IgE antibodies to thiopentone were detected. The other patient with similar symptoms showed no increase in the level of tryptase, nor any specific IgE to thiopentone or suxamethonium. These data indicate the patient I suffered from true anaphylaxis, whereas the reaction of patient II occurred by a different mechanism.

A new radioimmunoassay for human mast cell tryptase using monoclonal antibodies.

A solid phase immunoradiometric assay was developed for the quantitation of tryptase released from activated human mast cells. Tryptase exhibits a linear dose-response curve over the standard range of 2-50 micrograms/l in buffer, serum, and plasma. The dose-response curve approached a plateau at a tryptase concentration of 100 micrograms/l and exhibited partial inhibition at concentrations above 10,000 micrograms/l. The sensitivity of the assay was 0.2-0.4 micrograms/l, and the intra-assay and interassay coefficients of variation were below 4% at 2 micrograms/l or higher tryptase concentrations. The recovery of known amounts of purified tryptase added to serum ranged from 91 to 115%. Detection of tryptase was evaluated with several body fluids and was accurate in sera, plasma, bronchoalveolar lavage fluid, nasal lavage fluid, and saliva. The concentration of tryptase was examined in serum samples from 100 healthy controls; in each case the level was less than 2 micrograms/l. The immunoassay also was utilized to examine serum levels of tryptase after the onset of a hypotensive reaction in one patient receiving general anesthesia. A maximally elevated level of tryptase (25 micrograms/l) was detected at the first time point, 0.5 h, and elevated levels persisted to 6 h before a return to normal levels was documented at 24 h. Thus, the involvement of mast cell activation in hypotensive subjects can be ascertained by this new tryptase radioimmunoassay.