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Biomedical subjects

G Hansen

Publications and source records attributed to G Hansen.

154 records · Page 9Linked to original sources
PubMedDate not supplied

When engineered to produce latent TGF-beta1, antigen specific T cells down regulate Th1 cell-mediated autoimmune and Th2 cell-mediated allergic inflammatory processes.

To determine whether T cells which produce large amounts of latent TGF-beta1 are capable of down-regulating autoimmune and allergic disease, myelin basic protein (MBP)-specific and ovalbumin (OVA)-specific BALB/c cloned Th1 cells were transduced with cDNA for murine TGF-beta1 by coculture with fibroblasts producing a genetically engineered retrovirus. The transduced MBP-specific Th1 cells were found to lose the capacity to provoke EAE in BALB/c mice, and to gain instead the ability to protect against EAE in (SJLxBALB/c) F1 mice immunized with proteolipid protein (PLP). This protective effect was not obtained with OVA-specific TGF-beta1 transduced Th1 cells. The transduced OVA-specific Th1 cells did protect against airway hyperreactivity induced by Th2-cell mediated responses to inhaled OVA. This effect was again antigen specific and it also could not be obtained with untransduced OVA-specific Th1 cells. In both cases these effects of antigen specific TGF-beta1 transduced T cells were nullified by administration of neutralizing anti-TGF-beta mAb. Thus, the antigen specificity of the cloned T cells allows the site-specific local delivery of therapeutic active TGF-beta1 to both Th1 and Th2 cell-mediated inflammatory infiltrates.

Animals↗
PubMedDate not supplied

GC-MS-MS confirmation of unusually high delta 9-tetrahydrocannabinol levels in two postmortem blood samples.

Unusually high levels of delta 9-tetrahydrocannabinol (delta 9-THC) were detected in two postmortem blood samples. Because of sample decomposition, the major metabolite, 11-nor-9-carboxy-tetrahydrocannabinol (delta 9-THCCOOH), could not be determined using the routine EI-MS technique, which cast some doubt on the delta 9-THC result. Analysis of the sample extracts by GC-MS-MS confirmed the presence of delta 9-THC, although no delta 9-THCCOOH was detected.

Dronabinol↗
PubMedDate not supplied

Hemodynamic comparisons of polyurethane trileaflet and bioprosthetic heart valves.

Hemodynamic comparison of two polyurethane prosthetic heart valves with a bioprosthetic valve is presented. The valves were incorporated in a pulse duplicator simulating physiologic pulsatile flow, and comparisons between the valves were made on the transvalvular pressure drop, percent regurgitation, valve orifice area, rate of opening and closing as well as the performance index. The results showed that the functional characteristics of the polyurethane valve compared favorably with that of the bioprosthetic valve. The polyurethane valve can be a viable and inexpensive alternative, especially for short-term use in a total artificial heart as a bridge to transplant.

Bioprosthesis↗
PubMedDate not supplied

The characterization of crude products from solid-phase peptide synthesis by mu-HPLC/fast atom bombardment mass spectrometry.

Crude product mixtures from the solid-phase synthesis of a series of peptides were analyzed by on-line packed, fused silica column mu-HPLC/Continuous Flow Fast Atom Bombardment Mass Spectrometry (mu-HPLC/CF-FABMS). The technique is superior to the direct FAB analysis of crude product mixtures since competitive ionization and suppression effects are not generally observed. Positive correlation between a chromatographic peak and the desired synthetic product may be obtained. An accurate assessment of peptide deprotection can be made without ambiguity arising from the MS fragmentation of the more labile t-butyl and BOC protecting groups used in FMOC-based solid-phase peptide synthesis strategies. mu-HPLC combined with in-line UV detection and MS analysis allows the use of minimum sample and injection volumes, typically 10-50 pmol contained in 0.2-0.5 microliters.

Amino Acid Sequence↗
PubMedDate not supplied

Deposition of blood elements on vacuum-formed ventricles in calves. A gross and electron microscopic study.

The thrombogenicity of the Philadelphia Heart System was evaluated by implanting left and right ventricles in calves for periods ranging from 1.5 hours to 128 days. Explanted hearts were examined grossly and by scanning and transmission electron microscopy for accumulation of thrombus and ingrowth of pseudoneointima. Visible material was essentially limited to inflow and outflow valves, atrial cuff, and a circumferential band of white thrombus around the junction of the blood diaphragm with the housing. The band was barely visible at 33 days, but was 1 to 3 mm wide at 128 days. SEM examination revealed microscopic deposits of blood elements, mostly platelets, that were present between 10 days and 128 days. The deposits were rather uniformly distributed over the blood contacting surface and remained constant over time. At 128 days, the Dacron (Meadox Medical, Oakland, NJ) graft was partly covered by a thin layer of tissue composed of multiple layers of cells separated by collagen. New blood vessels were frequently found, but fibrin-rich thrombus was present in some areas. Thus, this system was capable of minimizing thrombus accumulation and remained stable for 4 months.

Animals↗