Development and function of T cells in mice rendered interleukin-2 deficient by gene targeting.

Interleukin-2 (IL-2) is a lymphocytotropic hormone which is thought to have a key role in the immune response of mammalian cells. It is produced by a subpopulation of activated T-lymphocytes and acts in vitro as the principal auto- and paracrine T-cell growth factor (for reviews see refs 1-3). IL-2 is, however, not the sole T-cell growth factor, nor does it act exclusively on T cells, also promoting growth of NK cells and differentiation of B cells. A role for IL-2 in T-cell development has been postulated but remains controversial. Here we test the requirement for IL-2 in vivo using IL-2-deficient mice generated by targeted recombination. We find that mice homozygous for the IL-2 gene mutation are normal with regard to thymocyte and peripheral T-cell subset composition, but that a dysregulation of the immune system is manifested by reduced polyclonal in vitro T-cell responses and by dramatic changes in the isotype levels of serum immunoglobulins.     

The Huntington's disease candidate region exhibits many different haplotypes.

Analysis of 78 Huntington's disease (HD) chromosomes with multi-allele markers revealed 26 different haplotypes, suggesting a variety of independent HD mutations. The most frequent haplotype, accounting for about one third of disease chromosomes, suggests that the disease gene is between D4S182 and D4S180. However, the paucity of an expected class of chromosomes that can be related to this major haplotype by assuming single crossovers may reflect the operation of other mechanisms in creating haplotype diversity. Some of these mechanisms sustain alternative scenarios that do not require a multiple mutational origin for HD and/or its positioning between D4S182 and D4S180.     

Hydrobiologische Anstalt Plön der Max-Planck-Gesellschaft zur Förderung der Wissenschaften

Ohne Zusammenfassung     

Réactions cytologiques à l'introduction pulmonaire expérimentale de particules de silicium métalloïdique

Summary By means of intratracheal injection, particles of metalloid silicium about five microns in size are introduced into the lungs of guinea pigs, and the secondary parenchymatous reactions are studied from 10 minutes to 105 days. In the dust cells, the silicium is progressively broken up into very small particles of less than 1 micron in size. The cells do not show degeneration or mummification as the ordinary silica cells (Mavrogordato) do.     

Rare Earth Doped Polymer Waveguide Materials and Devices

1 Results Rare earth doped waveguide amplifiers and devices have been demonstrated in silica, crystal and other glass hosts. These rare earth doped optical waveguide devices are based on inorganic materials. Many processing steps are required and can lead to long fabrication time and low yield.Polymer materials offer many distinct properties compared to inorganic materials, such as ease of fabrication, low production costs, simple processing steps, and compatibility with micro-fabrication technologies. ...     

La structure de certaines terminaisons nerveuses montre des variations cycliques

Summary All sensory endings of the trigeminal nerve in the dura mater of the rat are formed by a small swelling, from which continues themetaterminal apparatus, fine filaments at the limit of visibility. Periodically the fine granules at the extremity of the filaments swell, whereas the fibrils themselves disappear, leaving a small, round, argentophil mass. Later the filaments reappear, then redeposit their debris, which persists for a time.Thus the metaterminal apparatus manifests cyclic variations, which recall the transitory existence of collaterals observed duringin vivo orin vitro development of nerve fibres.