Neutron observation of phase and amplitude modes in an n=4 incommensurate system.
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Journal Article↗
Biomedical subjects
P Launois
Publications and source records attributed to P Launois.
[Hepatocytic hamartomas of the liver].
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Adolescent↗
Phenolic glycolipid-1 from M. leprae inhibits oxygen free radical production by human mononuclear cells.
We studied the effect of PGL1, a phenolic glycolipid unique to Mycobacterium leprae, on the activation of the phagocyte oxidative respiratory burst, by measuring the chemiluminescence (CL) generated by normal mononuclear cells. PGL1 induced a decrease in oxygen free radical production stimulated by mycobacteria (M. leprae, BCG and M. kansasii) or by phorbol myristate acetate, but did not prevent the binding or ingestion of fluorescein-conjugated mycobacteria. In contrast, mycoside A from M. kansasii, a structurally related compound, did not alter the CL response. In addition, treatment of M. leprae with anti-PGL1 antibodies failed to restore the response to this microorganism. PGL1 could act as an oxygen species scavenger and protect M. leprae from killing by toxic oxygen metabolites.
Adult↗
Mycobacterium leprae-reactive T-cell clones isolated from polar lepromatous and tuberculoid leprosy patients.
T-cell clones capable of mounting a proliferative response to Mycobacterium leprae were obtained in three leprosy patients (two polar lepromatous and one polar tuberculoid) either from M. leprae-activated or from protein-purified derivative-activated polyclonal T lymphoblasts. All these clones expressed the CD4 surface marker. Some of them proliferated to the antigen only in the presence of interleukin-2. A majority expressed cross-reactive responses to other mycobacteria. Clones obtained from the lepromatous patients did not differ in any of these features from those obtained from the tuberculoid patient. M. leprae-reactive clones obtained from one lepromatous patient displayed strong antigen-specific cytotoxicity toward autologous antigen-coated target cells. This phenomenon was not observed for any clone of the other lepromatous patient and was seen only for one clone in the tuberculoid patient.
Antigens, Bacterial↗
Original magnetic alignment of a nematic phase containing single-walled nanotubes.
Dispersions of single-walled carbon nanotubes in a 4-pentyl-4'-cyano-biphenyl nematic liquid crystal matrix are studied by X-ray scattering. For some mixtures, the addition of nanotubes strongly modifies the properties of the matrix: under a magnetic field, the nematic director is aligned perpendicular to the field, whereas it is parallel to it for pure 4-pentyl-4'-cyano-biphenyl. This original modification of liquid crystal alignment by the addition of nanotubes raises new questions about nanotubes and liquid crystal interactions.
Anisotropy↗
Some of the early events underlying Th2 cell maturation and susceptibility to Leishmania major infection in BALB/c mice.
The first experimental evidence for the development of polarized CD4+ Th1 and Th2 responses in vivo has been obtained using the murine model of infection with Leishmania major, an intracellular parasite of macrophages in their vertebrate host. Genetically determined resistance and susceptibility to infection with this parasite have been clearly demonstrated to result from the development of polarized Th1 and Th2 responses, respectively. Using this model system, the dominant role of cytokines in the induction of polarized CD4+ responses has been validated in vivo. The requisite role of IL-4 in mediating both Th2 differentiation and susceptibility to infection in BALB/c mice has directed interest towards the search for evidence of IL-4 production early after infection and identification of its cellular source. We have been able to demonstrate a burst of IL-4 production in susceptible BALB/c mice within the first day of infection with L. major and could establish that this rapidly produced IL-4 instructed Th2 lineage commitment of subsequently activated CD4+ T cells and stabilized this commitment by downregulating IL-12 Rbeta2 chain expression, resulting in susceptibility to infection. Strikingly, this early IL-4 response to infection resulted from the cognate recognition of a single epitope in a distinctive antigen, LACK, from this complex microorganism by a restricted population of CD4+ T cells that express Vbeta4-Valpha8 T cell receptors.
Animals↗