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Biomedical subjects

A Villena

Publications and source records attributed to A Villena.

59 records · Page 4Linked to original sources
PubMed1982

Increase in size of sonicated phospholipid vesicles in the presence of detergents.

Triton X-100, sodium dodecylsulphate, sodium cholate, and beta-octylglucoside increase the size of sonicated, but not of unsonicated, phospholipid vesicles above the Tc gel to liquid-crystalline transition temperature. Lysophosphatidylcholine or glyceryl monooleate do not increase liposome size under these circumstances. The observed phenomenon of vesicle growth is virtually unaffected by phospholipid composition, surface potential, calcium ions, EDTA, or albumin. The presence of cholesterol makes the vesicles more susceptible to detergent-induced growth. The presence of detergents, even at concentrations much lower than required to observe any increase in vesicle size, favors the liberation of vesicle contents. These results may have implications concerning membrane fusion as well as the reconstitution of membrane proteins in the presence of detergents.

Calcium↗
PubMed1981

Ultrastructure of the jugular body of Rana pipiens.

The jugular bodies in adult Rana pipiens, are surrounded by a capsule of mesothelium and connective tissue, and their parenchyma consists of cell cords arranged in a sinusoidal network. The cell cords are formed by irregular reticular cells, showing numerous filaments and joined together by zonulae adherents. The intercellular spaces are filled by reticular fibres and free cells. These latter are small and medium lymphocytes, lymphoblasts, and developing and mature plasma cells. Additionally, free macrophages, neutrophils and acidophils also occur. Sinusoidal blood vessels show thin walls with numerous filaments and pinocytotic vesicles. They exhibit a discontinuous basement membrane, and tight junctions frequently occur between endothelial cells. Occasionally, lymphatic vessels are found and the innervation is principally vasomotor, although nerve endings appear remarkably near reticular cells and lymphocytes. The jugular bodies of adult R. pipiens are plasma cell and antibody-forming organs, whose functional significance is discussed in relation to their ultrastructural organization.

Animals↗
PubMedDate not supplied

Two different subpopulations of Ig-bearing cells in lymphoid organs of rainbow trout.

In a previous report we described the existence of two structural and antigenic variants of light chains in serum trout Igs, defined by mAbs 2H9 and 2A1. In this report, we analyse the cell distribution, the "in vitro" kinetics of production, and the ontogenic appearance of these two variants. Both variants were already present at day 8 before hatching and their kinetics of appearance correlated with that of total Ig, showing a peak around hatching. These mAbs stained two distinct lymphoid cell populations in the pronephros, mesonephros, spleen, and peripheral blood. Both mAbs reacted with approximately 1% of thymocytes. The ratio between these two cell populations (2A1+/2H9+) was about 2/1 in the lymphoid organs analysed. No differences were found between the profiles of the "in vitro" production of these variants in pronephric cell cultures stimulated with LPS. In these cultures, the 2A1 and 2H9 Igs together accounted for 10-70% of the total trout Ig produced, suggesting the existence of at least one additional L chain variant.

Animals↗