Eosinophils adhesion assay as a tool for phenotypic drug screening - The pharmacology of 1,3,5 – Triazine and 1H-indole like derivatives against the human histamine H4 receptor

Histamine is a pleiotropic biogenic amine, having affinity towards four distinct histamine receptors. The existing pharmacological studies suggest the usefulness of histamine H4 receptor ligands in the treatment of many inflammatory and immunomodulatory diseases, including allergic rhinitis, asthma, atopic dermatitis, colitis or pruritus. Up to date, several potent histamine H4 receptor ligands were developed, none of which was registered as a drug yet. In this study, a series of potent indole-like and triazine derivatives were tested, in radioligand displacement and functional assays at histamine H4 receptor, as well as in human eosinophils adhesion assay to endothelium. For selected compounds permeability, cytotoxicity, metabolic and in vivo studies were conducted. Adhesion assay differentiated the activity of different groups of compounds with a known affinity towards the histamine H4 receptor. Most of the tested compounds downregulated the number of adherent cells. However, adhesion assay revealed additional properties of tested compounds that had not been detected in radioligand displacement and aequorin-based functional assays. Furthermore, for some tested compounds, these abnormal effects were confirmed during the in vivo studies. In conclusion, eosinophils adhesion assay uncovered pharmacological activity of histamine H4 receptor ligands that has been later confirmed in vivo, underscoring the value of well-suited cell-based phenotypic screening approach in drug discovery

Crystal structure and directed evolution of specificity of NlaIV restriction endonuclease

Specificity engineering is challenging, and particularly difficult for enzymes that have the catalytic machinery and specificity determinants in close proximity. Restriction endonucleases have been used as a paradigm for protein engineering, but successful cases are rare. Here, we present the results of a directed evolution approach to the engineering of a dimeric, blunt end cutting restriction enzyme NlaIV (GGN/NCC). Based on the remote similarity to EcoRV endonuclease, regions for random mutagenesis and in vitro evolution were chosen. The obtained variants cleaved target sites with an up to 100-fold kcat/KM preference for AT or TA (GGW/WCC) over GC or CG (GGS/SCC) in the central dinucleotide step, compared to the only ~17-fold preference of the wild-type enzyme. To understand the basis of the increased specificity, we determined the crystal structure of NlaIV. Despite the presence of DNA in the crystallization mix, the enzyme crystallized in the free form. We therefore constructed a computational model of the NlaIV-DNA complex. According to the model, the mutagenesis of the regions that were in the proximity of DNA did not lead to the desired specificity change, which was instead conveyed in an indirect manner by substitutions in the more distant regions

Cross Section Limits for the 208^{208}Pb(86^{86}Kr,n)293^{293}118 Reaction

In April-May, 2001, the previously reported experiment to synthesize element 118 using the $^{208}$Pb($^{86}$Kr,n)$^{293}$118 reaction was repeated. No events corresponding to the synthesis of element 118 were observed with a total beam dose of 2.6 x 10$^{18}$ ions. The simple upper limit cross sections (1 event) were 0.9 and 0.6 pb for evaporation residue magnetic rigidities of 2.00 $T m$ and 2.12 $T m$, respectively. A more detailed cross section calculation, accounting for an assumed narrow excitation function, the energy loss of the beam in traversing the target and the uncertainty in the magnetic rigidity of the Z=118 recoils is also presented. Re-analysis of the primary data files from the 1999 experiment showed the reported element 118 events are not in the original data. The current results put constraints on the production cross section for synthesis of very heavy nuclei in cold fusion reactions.Comment: 7 pages, 2 figures. Submitted to EPJ

Scaling Laws and Transient Times in 3He Induced Nuclear Fission

Fission excitation functions of compound nuclei in a mass region where shell effects are expected to be very strong are shown to scale exactly according to the transition state prediction once these shell effects are accounted for. The fact that no deviations from the transition state method have been observed within the experimentally investigated excitation energy regime allows one to assign an upper limit for the transient time of 10 zs.Comment: 7 pages, TeX type, psfig, submitted to Phys. Rev. C, also available at http://csa5.lbl.gov/moretto/ps/he3_paper.p

Isospin-tracing: A probe of non-equilibrium in central heavy-ion collisions

Four different combinations of $^{96}_{44}$Ru and $^{96}_{40}$Zr nuclei, both as projectile and target, were investigated at the same bombarding energy of 400$A$ MeV using a $4 \pi$ detector. The degree of isospin mixing between projectile and target nucleons is mapped across a large portion of the phase space using two different isospin-tracer observables, the number of measured protons and the ${\rm t}/^{3}{\rm He}$ yield ratio. The experimental results show that the global equilibrium is not reached even in the most central collisions. Quantitative measures of stopping and mixing are extracted from the data. They are found to exhibit a quite strong sensitivity to the in-medium (n,n) cross section used in microscopic transport calculations.Comment: 4 pages RevTeX, 3 figures (ps files), submitted to Phys. Rev. Let

Isospin influences on particle emission and critical phenomenon in nuclear dissociation

Features of particle emission and critical point behavior are investigated as functions of the isospin of disassembling sources and temperature at a moderate freeze-out density for medium-size Xe isotopes in the framework of isospin dependent lattice gas model. Multiplicities of emitted light particles, isotopic and isobaric ratios of light particles show the strong dependence on the isospin of the dissociation source, but double ratios of light isotope pairs and the critical temperature determined by the extreme values of some critical observables are insensitive to the isospin of the systems. Values of the power law parameter of cluster mass distribution, mean multiplicity of intermediate mass fragments ($IMF$), information entropy ($H$) and Campi's second moment ($S_2$) also show a minor dependence on the isospin of Xe isotopes at the critical point. In addition, the slopes of the average multiplicites of the neutrons ($N_n$), protons ($N_p$), charged particles ($N_{CP}$), and IMFs ($N_{imf}$), slopes of the largest fragment mass number ($A_{max}$), and the excitation energy per nucleon of the disassembling source ($E^*/A$) to temperature are investigated as well as variances of the distributions of $N_n$, $N_p$, $N_{CP}$, $N_{IMF}$, $A_{max}$ and $E^*/A$. It is found that they can be taken as additional judgements to the critical phenomena.Comment: 9 Pages, 8 figure

The systematic study of the influence of neutron excess on the fusion cross sections using different proximity-type potentials

Using different types of proximity potentials, we have examined the trend of variations of barrier characteristics (barrier height and its position) as well as fusion cross sections for 50 isotopic systems including various collisions of C, O, Mg, Si, S, Ca, Ar, Ti and Ni nuclei with $1\leq N/Z < 1.6$ condition for compound systems. The results of our studies reveal that the relationships between increase of barrier positions and decrease of barrier heights are both linear with increase of $N/Z$ ratio. Moreover, fusion cross sections also enhance linearly with increase of this ratio.Comment: 28 pages, 7 figures, 5 Table

Neglected patellar tendon rupture: a case of reconstruction without quadriceps lengthening

Neglected rupture of the patellar tendon is a rare, can be easily missed in a group of patients. We present a 24 year old, male patient who sustained right femoral diaphyseal and tibial plateau fractures and a patellar tendon rupture following a motor vehicle accident. The fractures were treated by open reduction internal fixation but the patellar tendon rupture was missed and the diagnosis was delayed by 7 months. Patella was migrated proximally. It was moved distally to the original location and neglected patellar tendon rupture treated successfully with modified Ecker technique. Neither preoperative traction nor additional intraoperative procedures were performed to relocate the patella to its anatomic position in the extended knee and good functional result was achieved with intensive rehabilitation

Direct comparison of phase-space distributions of K- and K+ mesons in heavy-ion collisions at SIS energies - evidence for in-medium modifications of kaons ?

The ratio of K- to K+ meson yields has been measured in the systems RuRu at 1.69 A GeV, Ru+Zr at 1.69 A GeV, and Ni+Ni at 1.93 A GeV incident beam kinetic energy. The yield ratio is observed to vary across the measured phase space. Relativistic transport-model calculations indicate that the data are best understood if in-medium modifications of the kaons are taken into account.Comment: 14 pages including 3 figure