Inhibition of EBV-induced lymphoproliferation by CD4(+) T cells specific for an MHC class II promiscuous epitope

Posttransplant lymphoproliferative disorder (PTLD) and B cell lymphomas induced by EBV continue to be a major life-threatening complication in transplant patients. The establishment and enhancement of T cell immunity to EBV before transplantation and immunosuppressive therapy could help diminish these complications, but the lack of an effective vaccine has limited this prophylactic approach. We describe here the identification of a peptide epitope from the EBV EBNA2 Ag that is capable of inducing in vitro CD4(+) T cell responses that inhibit the EBV-mediated B lymphocyte proliferation associated with PTLD. Most significantly, T cell responses to the EBNA2 epitope were found to be restricted by numerous MHC class II alleles (DR1, DR7, DR16, DR52, DQ2, and DQ7), indicating that this peptide is highly promiscuous and would be recognized by a large proportion (>50%) of the general population. These results are relevant for the design of a simple, inexpensive and widely applicable peptide-based vaccine to prevent PTLD in solid organ transplant patients.     

Fatigue complaints among female shift workers in a computer factory of Japan

For female workers in a computer factory in Japan, consisting of 41 daytime workers and 74 weekly-rotating shift workers (of whom, 37 each were engaged in, respectively, early-shift work and late-shift work during the survey week), within-day variations in the number of fatigue complaints were elucidated. Based on a repeated questionnaire survey, changes of fatigue complaints in a day were evaluated at three occasions, i.e., just before work, just after work, and before retiring, for three working days and one off day. The occasions of fatigue feelings differed among the three work groups: the complaints were significantly more frequent before work in the early-shift workers, after work in the late-shift workers, and before retiring in the daytime workers. Feeling of fatigue before and after work may be disadvantageous to safety and efficiency of work.     

Tyr-199 and charged residues of pharaonis Phoborhodopsin are important for the interaction with its transducer

pharaonis Phoborhodopsin (ppR; also pharaonis sensory rhodopsin II, psRII) is a retinal protein in Natronobacterium pharaonis and is a receptor of negative phototaxis. It forms a complex with its transducer, pHtrII, in membranes and transmits light signals by protein-protein interaction. Tyr-199 is conserved completely in phoborhodopsins among a variety of archaea, but it is replaced by Val (for bacteriorhodopsin) and Phe (for sensory rhodopsin I). Previously, we (Sudo, Y., M. Iwamoto, K. Shimono, and N. Kamo, submitted for publication) showed that analysis of flash-photolysis data of a complex between D75N and the truncated pHtrII (t-Htr) give a good estimate of the dissociation constant K(D) in the dark. To investigate the importance of Tyr-199, K(D) of double mutants of D75N/Y199F or D75N/Y199V with t-Htr was estimated by flash-photolysis and was approximately 10-fold larger than that of D75N, showing the significant contribution of Tyr-199 to binding. The K(D) of the D75N/t-Htr complex increased with decreasing pH, and the data fitted well with the Henderson-Hasselbach equation with a single pK(a) of 3.86 +/- 0.02. This suggests that certain deprotonated carboxyls at the surface of the transducer (possibly Asp-102, Asp-104, and Asp-106) are needed for the binding.     

Differences between maize and rice in N-use efficiency for photosynthesis and protein allocation

The N-use efficiency for photosynthesis was higher in a C(4) plant, maize, than in a C(3) plant, rice, including rbcS antisense rice with optimal ribulose-1,5-bisphosphate carboxylase (Rubisco) content for CO(2)-saturated photosynthesis, even when photosynthesis was measured under saturating CO(2) conditions. The N cost for the C(4) cycle enzymes in maize was not large, and the lower amount of Rubisco allowed a greater N investment in the thylakoid components. This greater content of the thylakoid components as well as the CO(2) concentrating mechanism may support higher N-use efficiency for photosynthesis in maize.     

Effect of polyethylene glycol and dimethyl sulfoxide on the fusion of bovine nuclear transfer using mammary gland epithelial cells

The effects of polyethylene glycol and dimethyl sulfoxide (PEG/DMSO) treatment of donor cells on the fusion and subsequent development of bovine nuclear transfer embryos using mammary gland epithelial (MGE) cells before electrofusion (fresh MGE cells) was studied. The same study was conducted on those cells that were frozen and stored in liquid nitrogen, and then thawed (frozen-thawed MGE cells). Experiment 1 showed that the exposure time and pH of PEG/DMSO solution affected the fusion of nuclear transfer, and that a higher fusion rate was obtained when fresh MGE cells were exposed to PEG/DMSO solution at pH 8.0 for 5 min. In Experiment 2, the proportion of fused oocytes with fresh PEG/DMSO-treated cells (70 +/- 6%) was significantly higher than that with non-treated cells (50 +/- 13%, p < 0.05). The same tendency was observed when frozen-thawed cells as donor nuclei were used (48 +/- 6% vs. 34 +/- 12%, p < 0.05). In addition, PEG/DMSO treatment has neither harmful nor beneficial effects on the cleavage and development of the blastocyst stage of reconstructed embryos (p > 0.05). The fusion and cleavage rates of frozen-thawed cells were significantly lower than those of fresh cells (p < 0.05). After 10 blastocysts, derived from fresh PEG/DMSO-treated cells, were transferred to five recipient heifers, one live female calf was obtained. Experiment 3 showed that PEG/DMSO treatment reduced the viability of both fresh and frozen-thawed MGE cells (p < 0.05). We conclude that the PEG/DMSO treatment of fresh MGE cells, as well as the frozen-thawed cells, before electrofusion has a positive effect on the fusion of nuclear transfer without decreasing the in vitro development of reconstructed embryos.     

Suppression by Hydrangeae Dulcis Folium of D-galactosamine-induced liver injury in vitro and in vivo

Hydrangeae Dulcis Folium, the fermented and dried leaves of Hydrangea macrophylla SER. var. thunbergii MAKINO, suppressed D-galactosamine-induced liver injury by 85.2% when added to the diet at 1% and fed to rats for fifteen days. The hepatoprotective effect is more potent than that of a milk thistle extract and turmeric powder. Some fractionated extracts showed hepatoprotective activity in the D-galactosamine-induced in vitro liver injury model.     

Inhibitory effects of brown algal phlorotannins on secretory phospholipase A2s, lipoxygenases and cyclooxygenases

The inhibitory effects of brown algal phlorotannins on secretory phospholipase A₂s (sPLA₂s), lipoxygenases (LOXs) and cyclooxygenases (COXs) were determined with an in vitro assay. Oligomers of phloroglucinol; eckol (a trimer), phlorofucofuroeckol A (a pentamer), dieckol (a hexamer) and 8,8-bieckol (a hexamer) isolated from the brown alga Eisenia bicyclis had pronounced inhibitory effects on sPLA₂ from porcine pancreas and bee venom (IC₅₀ 100–200 M). The phlorotannins inhibited LOX activity more effectively than the well-known LOX inhibitors; resveratrol and epigallocatechin gallate. 8,8-Bieckol, the strongest LOX inhibitor in this study, inhibited soybean LOX and 5-LOX with IC₅₀ values of 38 and 24 M, respectively. Negligible or very weak effects of the phlorotannins on COX-1 and COX-2 were found, except for an inhibitory effect of dieckol on COX-1 (74.7%) and of eckol on COX-2 (43.2%) at 100 M.     

Annexin XI may be involved in Ca2+ - or GTP-gammaS-induced insulin secretion in the pancreatic beta-cell

The aim of this study was to investigate possible involvement of annexin XI in the insulin secretory machinery. In fluorescence immunocytochemistry, annexin XI was found in the cytoplasm of pancreatic endocrine cells and a pancreatic beta-cell line, MIN6, in a granular pattern. MIN6 cells also possessed weak and diffused annexin XI immunoreactivity in the cytoplasm. Immunoelectron microscopy revealed annexin XI in the insulin granules. Insulin secretion from streptolysin-O-permeabilized MIN6 cells was inhibited by anti-annexin XI antibody, when the release was stimulated by either Ca2+ or GTP-gammaS, but not by a protein kinase C-activating phorbol ester. Inhibition of insulin release by anti-annexin XI antibody was reproduced in permeabilized rat islets. These findings suggest that annexin XI may be involved in the regulation of insulin secretion from the pancreatic beta-cells.     

Gene expression profiles of cryopreserved CD34 human umbilical cord blood cells are related to their bone marrow reconstitution abilities in mouse xenografts

Human umbilical cord blood (UCB) cells are an alternative source of hematopoietic stem cells for treatment of leukemia and other diseases. It is very difficult to assess the quality of UCB cells in the clinical situation. Here, we sought to assess the quality of UCB cells by transplantation to immunodeficient mice. Cryopreserved CD34⁺ UCB cells from twelve different human donors were transplanted into sublethally irradiated NOD/shi-scid Jic mice. In parallel, the gene expression profiles of the UCB cells were determined from oligonucleotide microarrays. UCB cells from three donors failed to establish an engraftment in the host mice, while the other nine succeeded to various extents. Gene expression profiling indicated that 71 genes, including HOXB4, C/EBP-β, and ETS2, were specifically overexpressed and 23 genes were suppressed more than 2-fold in the successful UCB cells compared to those that failed. Functional annotation revealed that cell growth and cell cycle regulators were more abundant in the successful UCB cells. Our results suggest that hematopoietic ability may vary among cryopreserved UCB cells and that this ability can be distinguished by profiling expression of certain sets of genes.