| 1. |
- Persson, E, et al.
(författare)
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Plasma lipolytic activity and substrate oxidation after intravenous administration of heparin and a low molecular weight heparin fragment
- 1990
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Ingår i: Clinical Physiology. - 1365-2281. ; 10:6, s. 573-583
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Tidskriftsartikel (refereegranskat)abstract
- This study examines the effects of heparin and a low molecular weight heparin (LMWH) fragment on plasma lipolytic activity and substrate oxidation. Indirect calorimetry was performed continuously in healthy male subjects receiving a constant infusion of fat emulsion (0.2 g min-1) and glucose (0.8 g min-1) during a period of 4 h. After 2 h an infusion of heparin (n = 6) or LMWH (n = 6) (100 antifactor Xa units kg-1) or saline (n = 6) was given over 1 h. Plasma concentration of the fat emulsion decreased by 76 +/- 5% with heparin and by 12 +/- 7% with LMWH (P less than 0.01). In the case of LMWH the initial fall was followed by a consistent rise in fat emulsion concentration for the entire remaining study period. Compared to the control experiments, plasma FFA increased five times with heparin and three times with LMWH (P less than 0.05). The average respiratory quotient (RQ) and energy expenditure (EE) increased constantly during the study period and did not differ significantly between the groups. In all groups the average increase in glucose oxidation was 40-50%, while fat oxidation decreased to a comparable extent. Infusions of heparin and LMWH had no effect on RQ or EE. A microcalorimetric study on isolated rat adipocytes in buffer solutions containing glucose, fat emulsion, heparin or LMWH was also made. The heat output from the adipocytes was not influenced by the presence of heparin or LMWH. In conclusion, infusion of heparin resulted in a pronounced increase in FFA availability, whereas LMWH exerted a less marked lipolytic effect. However, the heparin-induced elevations in plasma FFA were not accompanied by measurable rises in lipid oxidation rate.
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| 2. |
- Chin, L. T., et al.
(författare)
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Site-directed primary in vitro immunization : Production of HIV-1 neutralizing human monoclonal antibodies from lymphocytes obtained from seronegative donors
- 1994
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Ingår i: Immunology. - 0019-2805. ; 81:3, s. 428-434
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Tidskriftsartikel (refereegranskat)abstract
- The design of an in vitro immunization system based on a synthetic heterotope immunogen, which was a peptide containing both T- and B-cell epitopes, that elicited a neutralizing, primary human humoral immune response against the human immunodeficiency virus (HIV-1) is reported here. This heterotope construct contained the major neutralizing B-cell epitope, within the V3 region of glycoprotein 120 (gp120), linked to a promiscuous helper T- cell epitope of tetanus toxin. The peptide was used to induce a human humoral in vitro immune response against the V3 region, using lymphocytes obtained from healthy, sero-negative blood donors. The in vitro immunized peripheral blood lymphocytes were Epstein-Barr virus infected and the antibody response to the synthetic peptide was evaluated using a solid-phase ELISA with the recombinant C-terminal fragment of gp120 (pB1, amino acid residues 287 467, derived from the HIV-1 LAI isolate). The heterotope construct yielded a significant frequency of specifically immunized B cells, in contrast to the control immunizations with individual T and B epitopes mixtures of these epitopes or no immunogen at all. This approach allowed us to generate human monoclonal antibodies, using lymphocytes derived from sero-negative donors, that cross-neutralized several HIV-1 strains, inhibited syncytia formation as well as prevented spreading of the viral infection from cell to cell. Thus, site-directed in vitro immunization using synthetic heterotopes might prove valuable in the dissection and induction of a protective humoral immune response.
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| 3. |
- Ohlin, M., et al.
(författare)
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Human MoAbs produced from normal, HIV-1-negative donors and specific for glycoprotein gp120 of the HIV-1 envelope
- 1992
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Ingår i: Clinical and Experimental Immunology. - : Oxford University Press (OUP). - 0009-9104 .- 1365-2249. ; 89:2, s. 290-295
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Tidskriftsartikel (refereegranskat)abstract
- Human MoAbs ofIgM class were developed against three regions of the HIV-1 envelope. Uninfected donor lymphocytes were immunized in vitro with recombinant protein pB1. Four out of five antibodies were directed to different parts of the V3 region, which contains a major neutralizing site. Two out of these antibodies were directed to more than one amino acid sequence, indicating reactivity to discontinuous sites. Two of the human MoAbs inhibited viral spread between cells in tissue culture, interpreted as reactivities to conserved amino acid sequences exposed during viral maturation. No MoAb neutralized virus, which may be explained by the relatively low avidity of the antibodies. One MoAb was directed to a region containing amino acids participating in CD4 binding. This technique appears to allow formation of antibodies with fine specificities other than those obtained in infected hosts.
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