Stimulation of bovine monocyte-derived macrophages with lipopolysaccharide, interferon-ɣ, Interleukin-4 or Interleukin-13 does not induce detectable changes in nitric oxide or arginase activity

Background: Bacterial lipopolysaccharide and interferon-γ stimulation of rodent macrophages in vitro induces up-regulation of inducible nitric oxide synthase, whereas interleukin-4 stimulation results in increased activity of arginase-1. Thus different stimulants result in differing macrophage phenotypes, appropriate for responses to a range of pathogens. The current study was conducted in order to determine whether bovine macrophages derived from monocytes and spleen respond similarly. Results: Lipopolysaccharide and interferon-γ did not induce detectable increases in nitric oxide production by bovine monocyte-derived or splenic macrophages in vitro. Similarly, interleukin-4 and interleukin-13 did not affect arginase activity. However, changes in transcription of genes coding for these products were detected. Conclusion: Differences between macrophage activation patterns exist between cattle and other species and these differences may occur during the post-transcription phase

Does the frontal sensory organ in adults of the hoplonemertean Quasitetrastemma stimpsoni originate from the larval apical organ?

BACKGROUND: The apical organ is the most prominent neural structure in spiralian larvae. Although it has been thoroughly investigated in larvae of the class Pilidiophora in phylum Nemertea, studies on its structure in other nemertean larvae are limited. Most adult hoplonemertean worms have a frontal organ located in a position corresponding to that of the larval apical organ. The development and sensory function of the frontal organ has not been thoroughly characterized to date. RESULTS: The apical organ in the early rudiment stage of Quasitetrastemma stimpsoni larvae consists of an apical plate enclosed by ducts of frontal gland cells and eight apical neurons. The apical plate is abundantly innervated by neurites of apical neurons. During the late rudiment stage, the larval apical organ has external innervation from below by two subapical-plate neurons, along with 11 apical neurons, and its plate contains serotonin-like immunoreactive (5-HT-lir) cells. In the vermicular stage (free-swimming juvenile), the number of apical neurons is reduced, and their processes are resorbed. Serotonin is detected in the apical plate with no visible connection to apical neurons. In adult worms, the frontal organ has a small apical pit with openings for the frontal gland ducts. The organ consists of 8 to 10 densely packed 5-HT-lir cells that form the roundish pit. CONCLUSIONS: Although the ultrastructure of the Q. stimpsoni larval apical organ closely resembles that of the apical organ of Polycladida larvae, the former differs in the presence of flask-shaped neurons typical of Spiralia. Significant differences in the structure of the apical organs of hoplonemertean and pilidia larvae point to two different paths in the evolutionary transformation of the ancestral apical organ. Ultrastructural and immunoreactive analyses of the apical organ of a hoplonemertean larva in the late rudiment and vermicular stages and the frontal organ of the adult worms identified common morphological and functional features. Thus, we hypothesize that the larval apical organ is modified during morphogenesis to form the adult frontal organ, which fulfills a sensory function in the hoplonemertean worm. This unique developmental trait distinguishes the Hoplonemertea from other nemertean groups

Heat Transport in Spin Chains with Weak Spin-Phonon Coupling.

The heat transport in a system of S=1/2 large-J Heisenberg spin chains, describing closely Sr(2)CuO(3) and SrCuO(2) cuprates, is studied theoretically at T≪J by considering interactions of the bosonized spin excitations with optical phonons and defects. Treating rigorously the multiboson processes, we derive a microscopic spin-phonon scattering rate that adheres to an intuitive picture of phonons acting as thermally populated defects for the fast spin excitations. The mean-free path of the latter exhibits a distinctive T dependence reflecting a critical nature of spin chains and gives a close description of experiments. By the naturalness criterion of realistically small spin-phonon interaction, our approach stands out from previous considerations that require large coupling constants to explain the data and thus imply a spin-Peierls transition, absent in real materials

The formation of the superheavy hydrogen isotope H-6 in the absorption of stopped pi(-)-mesons by nuclei

An experimental search for the superheavy hydrogen isotope H-6 was conducted through studying the absorption of stopped pi(-)-mesons by Be-9 and B-11 nuclei. A structure in the missing mass spectrum caused by the resonance states of H-6 was observed in three reaction channels, namely, Be-9(pi(-), pd)X, B-11(pi(-), d(3)He)X, and B-11(pi(-), p(4)He)X. The parameters of the lowest state E-r = 6.6 +/- 0.7 MeV and Gamma = 5.5 +/- 2.0 MeV (E-r is the resonance energy with respect to the disintegration into the triton and three neutrons) are evidence that H-6 is a more weakly bound system than H-4 and H-5. Three excited states of H-6 were observed. Their resonance levels (E-1r = 10.7 +/- 0.7 MeV, Gamma(1r) = 4 +/- 2 MeV, E-2r = 15.3 +/- 0.7 MeV, Gamma(2r) = 3 +/- 2 MeV, and E-3r = 21.3 +/- 0.4 MeV, Gamma(3r) = 3.5 +/- 1.0 MeV) are energetically capable of disintegrating into six free nucleons. (C) 2003 MAIK "Nauka / Interperiodica"