Effectiveness of donor natural killer cell alloreactivity in mismatched hematopoietic transplants

T cells that accompany allogeneic hematopoietic grafts for treating leukemia enhance engraftment and mediate the graft-versus-leukemia effect. Unfortunately, alloreactive T cells also cause graft-versus-host disease (GVHD). T cell depletion prevents GVHD but increases the risk of graft rejection and leukemic relapse. In human transplants, we show that donor-versus-recipient natural killer (NK)-cell alloreactivity could eliminate leukemia relapse and graft rejection and protect patients against GVHD. In mice, the pretransplant infusion of alloreactive NK cells obviated the need for high-intensity conditioning and reduced GVHD. NK cell alloreactivity may thus provide a powerful tool for enhancing the efficacy and safety of allogeneic hematopoietic transplantation.     

Effect of antagonistic Fusarium spp. and of different commercial biofungicide formulations on Fusarium wilt of basil (Ocimum basilicum L.)

The ability of antagonistic Fusarium spp. to control Fusarium wilt of basil caused by F. oxysporum f. sp. basilici was tested under glasshouse conditions from 1994 to 1996. Fusarium oxysporum antagonistic strain 251/2, a protoplast fusion-derived hybrid coded FI-11 and F. moniliforme strains TF4 and TF4 RB were able to decrease (P = 0.05) the incidence of Fusarium wilt significantly. Biocontrol was consistent, especially when the antagonists were applied by mixing a talc preparation of propagules in the substrate (10⁵ CFU/ml of substrate) 1–2 weeks before sowing or at sowing. Seed coating with the biocontrol strains (10⁸ CFU/g of seed) did not generally provide sufficient disease containment, whereas the combination of substrate treatment and seed coating did not improve wilt control in comparison with substrate treatment alone. Two commercial formulations, based on antagonistic F. oxysporum strains and one containing the antagonistic strain K61 of Streptomyces griseoviridis, were generally not sufficiently effective at the tested dosages.     

Formation of tetracycline degradation products in chicken and pig meat under different thermal processing conditions

Tetracycline (TC) and 4-epitetracycline (4eTC) degradation, as well as anhydrotetracycline (ATC) and 4-epianhydrotetracycline (4eATC) formation, has been evaluated in thermally treated chicken breast, pig loin, and pig loin with added back-fat. Samples containing TC and 4eTC residues were submitted to microwave or boiling heating, extracted with a mixture of McIlvaine buffer/methanol (75:25), and analyzed by high-performance liquid chromatography-diode array detection on a phenyl-hexyl reverse phase chromatographic column. The formation of ATC and 4eATC, as well as of two unidentified compounds, was described for the first time in edible meat samples submitted to mild thermal treatments, similar to those applied at home to cook foods. Degradation of TC and 4eTC and formation of ATC and 4eATC versus time of treatment fitted satisfactorily a first-order kinetic. Even if the potential toxic effects of these breakdown compounds should be further investigated, their formation in cooked meat should be taken into account when maximum residue limits are established.