Longterm survival of transplanted human corneal epithelial cells and corneal stem cells

PURPOSE: To investigate the survival of donor-derived epithelial cells in conventional penetrating keratoplasty (PKP) and in homologous penetrating central limbal keratoplasty (HPCLK). METHODS AND PATIENTS: Epithelial cells from 26 eyes of 26 patients were analysed. All cases were sex-mismatched (i.e. the transplant and patient were of different genders). At suture removal more than 1 year post surgery, epithelial cells were obtained by gently wiping the removed sutures on glass slides. The cell samples were analysed using fluorescent in situ hybridization (FISH) of the sex chromosomes. This technique makes it possible to allocate the origin of each cell nucleus to either the donor or the recipient. RESULTS: All 19 conventional PKPs were clear and seven had donor-derived epithelial cells at suture removal. Five of the seven HPCLK grafts were clear at the time of investigation (365-1355 days post surgery), and donor-derived epithelial cells were found in two grafts. CONCLUSION: Harvesting cells from removed sutures in combination with FISH enables the clinical study of cell survival in corneal transplants without jeopardizing functioning grafts. From the limited sample investigated, the following tentative conclusions can be made. Donor-derived epithelial cells can remain in conventional PKP for over 1 year. In combined stem cell and corneal grafts (HPCLK), donor-derived epithelial cells may also be retrieved at 1 year or beyond following surgery but the correlation between their presence and a remaining clear graft is uncertain.     

Two weeks of overfeeding with candy,but not peanuts,increases insulin levels and body weight

Objective: To study the effects of snacking based on fast acting carbohydrates (candy) or fat and protein (peanuts) in a prospective randomized, parallel intervention study. Methods: Basal metabolic rate (BMR) and cardiovascular risk factors were measured before and after hyper-alimentation by addition of 20kcal/kg (84kJ/kg) body weight of either candy or roasted peanuts, to the regular caloric intake, for two weeks in healthy subjects. Eleven men and 14 women completed the randomized study. Results: Energy-intake increased similarly in the groups (candy: +46.1±35%, peanuts: +46.8±28% p=0.96). Body-weight (candy: from 67.3±7.6kg to 68.1±7.3kg, p=0.01, nuts: from 68.7±6.1kg to 69.0±5.7kg p=0.3) and waist circumference increased significantly only in the candy group. At the end of the study LDL cholesterol (candy: 2.6±0.4mmol/l peanuts: 2.1±0.4mmol/l, p=0.005) and ApoB/ApoA-1-ratio (candy: 0.68±0.16 peanuts 0.53±0.11, p=0.01) were higher in the candy group than in the peanut group. On the other hand, BMR increased only in the peanut group (candy: from 6.657±1.1MJ/24h to 6.762±1.1MJ/24h, p=0.3 nuts: from 6.896±0.98MJ/24h to 7.256±1.1MJ/24h, p=0.02). Conclusion: Two weeks of snacking based on peanuts does not cause the same negative metabolic effects as an isocaloric diet in which the snacking is based on short acting carbohydrates in the form of candy in non-obese healthy subjects.     

Expression of mast cell tryptases in Hodgkin and Reed-Sternberg (HRS) cells

Tryptase is the most abundant protease in human mast cells, and is often used as a marker for the enumeration of mast cells in tissue. Here we report that tumour cells from Hodgkin lymphoma, the so called Hodgkin and Reed-Sternberg cells, can express tryptase. Hodgkin lymphoma cell lines expressed mRNA for both α- and β-tryptase and also produced the protein, although at much lower concentrations than mast cells. However, the frequency of tryptase positive HRS-cells in situ was very low. This report demonstrates that tumour cells of lymphoid origin can express tryptase in vitro and in situ .     

MHC class I cross-talk with CD2 and CD28 induces specific intracellular signalling and leads to growth retardation and apoptosis via a p56(lck)-dependent mechanism

Ligation of the major histocompatibility complex class I molecules (MHC-I) on human T lymphoma cells (Jurkat) initiates p56(lck)-dependent intracellular signalling events (phosphotyrosine kinase activity; [Ca(2+)](i)) and leads to augmented growth inhibition and apoptosis. MHC-I ligation in concert with ligation of CD2 or CD28 augments, changes or modifies the pattern of activation. Ligation of MHC-I and CD2 alone resulted in growth inhibition, whereas CD28 ligation alone had no effect on cell proliferation. Ligation of MHC-I together with CD2 augmented growth inhibition and enhanced the level of apoptosis. In parallel experiments with the p56(lck)-negative Jurkat mutant cell, JCaM1.6, cross-linking neither influenced cell signalling nor cellular growth functions, indicating a cardinal role of the src kinases in signal transduction via MHC-I, CD2 and CD28 molecules. The results presented here provide evidence for the involvement of MHC-I molecules in the modulation of signal transduction via the CD2 and CD28 costimulatory molecules. Copyright Copyright 1999 S. Karger AG, Basel     

Expression of cyclo-oxygenase-2 in human atherosclerotic carotid arteries.

OBJECTIVES: the preventive effect of acetylsalicylic acid in cardiovascular disease may be due to inhibition of platelet aggregation mediated by COX-1, but may in addition be due to anti-inflammatory effects by inhibition of COX-2. The objective of this study was to analyse the expression of COX-1 and COX-2 in atherosclerotic and healthy vascular walls. DESIGN: the expression COX-1 and COX-2 was analysed in biopsies from human atherosclerotic carotid arteries and from healthy mammary arteries and saphenous veins. Materials: vascular biopsies were obtained from patients undergoing carotid endarterectomy or coronary bypass surgery. METHODS: RT-PCR was used for mRNA analysis and for localization of proteins we used immunohistochemistry. RESULTS: COX-2 was found in atherosclerotic plaques: in macrophages, in some smooth muscle cells and in endothelial cells of small vessels in the lesions. In non-atherosclerotic blood vessels, COX-2 was detected in the endothelium of the vasa vasorum in the adventitia. COX-1 was found in the endothelium in healthy and in atherosclerotic vessels. CONCLUSIONS: the expression of COX-2 by inflammatory and vascular cells in atherosclerotic arteries suggests that products of this enzyme may be important in the pathogenesis of atherosclerosis.     

Tumor-associated antigens identified by mRNA expression profiling induce protective anti-tumor immunity

Defined tumor-associated antigens (TAA) are attractive targets for anti-tumor immunotherapy. Here, we describe a novel genome-wide approach to identify multiple TAA from any given tumor. A panel of transplantable thymomas was established from an inbred p53-/- mouse strain. The resulting tumors were examined for gene expression by mRNA microarray scanning. This analysis revealed heterogeneity of the tumors in agreement with the assumption that they represent different tumorigenic events. Several genes were overexpressed in one or more of the tumors. To examine whether overexpressed genes might be used to identify TAA, mice were immunized with mixtures of peptides representing putative cytotoxic T cell epitopes derived from one of the gene products. Indeed, such immunized mice were partially protected against subsequent tumor challenge. Despite being immunized with bona fide self antigens, no clinical signs of autoimmune reactions were observed. Thus, it appears possible to evaluate the entire metabolism of any given tumor and use this information rationally to identify multiple epitopes of value in the generation of tumor-specific immunotherapy. We expect that human tumors express similar tumor-specific metabolic imprints, which may be used to identify patient-specific arrays of TAA. This may enable a multi-epitope based immunotherapy with improved prospects of clinical tumor rejection.     

T-cell activation. I. Evidence for a functional linkage between class I MHC antigens and the Tc-Ti complex

This paper examines the possibility of a functional linkage between class I MHC molecules and the T-cell receptor complex for antigen (T3-Ti). A newly developed anti-CD3 antibody (500A2) was used as an activation signal for EL4 lymphoma cells and allospecific cytotoxic T-cell clones (CTL), and the production of IL-2/IL-2 receptor in EL4 cells and serine esterase in CTL was determined. Anti-CD3 antibody-induced activation of both EL4 and CTL cells was enhanced in the presence of immunologically cross-linked and immobilized anti-H-2 (class I) antibody reactive against the H-2 haplotype of the responding T cells. A number of H-2-negative and H-2-positive EL4 subclones were generated and tested for anti-CD3 antibody-induced IL-2/IL-2 receptor production. Although both H-2-positive and -negative subclones expressed CD3 antigen and produced IL-2 after activation with the phorbol ester TPA, only the H-2-positive cell clones produced IL-2 and expressed IL-2 receptor after anti-CD3 antibody induction. Our results are compatible with the existence of a functional linkage between the class I and the CD3 molecules on the surface of T cells.