Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0018133 (graft-versus-host disease)
 18,032 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

UVB irradiation of bone marrow or pancreatic islets has been shown to prevent GVHD and to induce transplant tolerance in experimental animal models. To clarify the underlying mechanism(s) responsible for these UVB effects we have examined in vitro cell function following UVB irradiation using LDA, FACS analysis, and DNA gel electrophoresis to assess the role of UVB-induced anergy and/or cell death. To extend our studies to the clinical setting and to promote chimerism and tolerance to organ allografts, we have further studied the effects of UVB irradiation combined with the commonly used immunosuppressive agents (cyclosporine, azathioprine, and methylprednisolone) on human T cells in proliferative in vitro assays. When cytotoxic and proliferative responses to allogeneic cells or to PHA stimulation were evaluated in LDA, the use of increasing doses of UVB irradiation resulted in a dose-dependent decrease in proliferative and cytotoxic responses of T-cells as seen by decreases in precursor frequencies. The results of proliferative T-cell assays suggest an additive immunosuppressive effect of various immunosuppressive drugs when combined with UVB irradiation. Gel electrophoresis of DNA derived from resting and activated, UVB-irradiated PBLs showed apoptosis at all UVB doses used. FACS analysis of UVB-treated CD2+ cells resulted in a UVB dose-related decrease in cell numbers that correlated with viability studies. It appears that UVB irradiation of both activated and resting PBLs induces programmed cell death but not anergy of T-cells.
 ...
PMID:UVB irradiation of human-derived peripheral blood lymphocytes induces apoptosis but not T-cell anergy: additive effects with various immunosuppressive agents. 864 Aug 73

Irradiation of whole blood and blood components before transfusion is currently the only accepted method to prevent Transfusion-Associated Graft-Versus-Host-Disease (TA-GVHD). However, choosing the appropriate technique to determine the dosimetric parameters associated with blood irradiation remains an issue. We propose a dosimetric system based on the standard Fricke Xylenol Gel (FXG) dosimeter and an appropriate phantom. The modified dosimeter was previously calibrated using a (60)Co teletherapy unit and its validation was accomplished with a (137)Cs blood irradiator. An ionization chamber, standard FXG, radiochromic film and thermoluminescent dosimeters (TLDs) were used as reference dosimeters to determine the dose response and dose rate of the (60)Co unit. The dose distributions in a blood irradiator were determined with the modified FXG, the radiochromic film, and measurements by TLD dosimeters. A linear response for absorbed doses up to 54 Gy was obtained with our system. Additionally, the dose rate uncertainties carried out with gel dosimetry were lower than 5% and differences lower than 4% were noted when the absorbed dose responses were compared with ionization chamber, film and TLDs.
 ...
PMID:Prevention of transfusion-associated graft-versus-host disease by irradiation: technical aspect of a new ferrous sulphate dosimetric system. 2376 45