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Pekka J Häyry: Influence Statistics

We have recently demonstrated that rat cytomegalovirus (RCMV) infection induces an early inflammatory response in the adventitia (perivasculitis) and in the subendothelial space (endothelialitis) as well as doubles smooth muscle cell (SMC) proliferation and intimal thickening of rat aortic allografts performed from the DA (AG-B4, RT1a) to the WF (AG-B2, RT1v) strain. In this study, the impact of RCMV infection on the structure of inflammation in the allograft adventitia and on the ...

We have investigated the immunogenic potential of rat heart vascular endothelial cells by their ability to induce an accelerated rejection of a relevant heart allograft, and related the immunogenic potential to the expression of class II major histocompatibility complex (MHC) antigens on the endothelial cell surface. Only 12% of freshly isolated rat vascular endothelial cells express class II antigens in serum-free medium, and the level of expression is low as judged by immunoperoxidase ...

Platelet-derived growth factors (PDGFs) and their receptors (PDGFRs) have been linked to vascular smooth muscle cell (SMC) migration and proliferation leading to atherosclerosis, restenosis, and chronic allograft rejection. This study describes the effect of CGP 53716, a specific PDGFR tyrosine kinase inhibitor on SMC proliferation and migration in vitro and in neointimal formation in vivo. CGP 53716 inhibited dose dependently tyrosine phosphorylation of both the known PDGFRs: the ...

Inbred DA (AG-B4, RT1a) and WF (AG-B2, RT1v) rats were used as donors and recipients of aortic allografts. The recipient rats were inoculated i.p. either on day 1 (early infection) or on day 60 (late infection) with 10(5) plaque-forming units of rat cytomegalovirus (RCMV). The control rats were left noninfected. The presence of viral infection was demonstrated by plaque assays from biopsies of the salivary glands, liver, and spleen at sacrifice. The rats received 300 microCi[3H]thymidine ...

This study is an investigation of whether a protocol biopsy may be used as surrogate to late graft survival in multicenter renal transplantation trials. During two mycophenolate mofetil trials, 621 representative protocol biopsies were obtained at baseline, 1 yr, and 3 yr. The samples were coded and evaluated blindly by two pathologists, and Chronic Allograft Damage Index (CADI) score was constructed. At 1 yr, only 20% of patients had elevated (>l.5 mg/100 ml) serum creatinine, whereas ...

Human natural killer cells cytotoxic against cell-line target cells (NK-CLT) were isolated and characterized by utilizing adsorption-elution of the effector cells from the K-562 target cells. The cell associated with the cytotoxicity was a large lymphocyte with pale and characteristically granular cytoplasm. Thus, its morphology was identical with that of the large granular lymphocyte (LGL) previously shown to be the principal cytotoxic NK cell against fetal fibroblasts (NK-FF). The ...

Summary. The long-term success of coronary angioplasty is limited by restonosis. This study was undertaken to investigate whether and to what extent the enhanced proliferative response observed in a balloon reinjury model of rat aorta is regulated by the PDGF receptor (PDGF-R). Balloon injury was performed to 14-day-old pre-existing neointimal lesion in rat aorta. PDGF receptor and ligand immunoreactivity were measured at several time points after the first and second injury, and PDGF-R ...

BACKGROUND: Porcine fetal pancreas is a potential source of beta cells for transplantation. The immaturity of the cells is a problem. We have defined the optimal conditions for in vitro propagation of this tissue before transplantation.

METHODS: Porcine fetal pancreas tissue was obtained for tissue culture at various stages of development. Serum-containing and serum-free media and a variety of potential differentiation factors were tested. In vitro, the numbers of endocrine islet cells ...

Accelerated allograft arteriosclerosis (chronic rejection) has emerged as a major factor affecting long-term survival of human cardiac allografts. The underlying mechanism of this disorder remains unclear. The purpose of this study was to investigate the effect of cyclosporine on the development of cardiac allograft arteriosclerosis at the cellular and molecular level. Heterotopic rat cardiac allografts from DA donors to WF recipients, with a strong genetic disparity in major ...

BACKGROUND: Cardiac allograft arteriosclerosis is a complex process of alloimmune response, chronic inflammation, and smooth muscle cell proliferation that includes cross talk between cytokines and growth factors.

METHODS AND RESULTS: Our results in rat cardiac allografts established alloimmune response as an alternative stimulus capable of inducing vascular endothelial growth factor (VEGF) mRNA and protein expression in cardiomyocytes and graft-infiltrating mononuclear inflammatory ...

In human kidney allografts, association of acute rejection and glomerulopathy with cytomegalovirus (CMV) infection has been demonstrated. To investigate the effect of CMV infection on the development of experimental chronic kidney allograft rejection, heterotopic kidney allografts from DA (Ag-B4, RT1a1) rat donors to WF (Ag-B2, RT1u) rat recipients were used. The animals received cyclosporine A (CsA) 5 mg/kg/day s.c. either for 1 or 12 weeks. Two groups of recipients were infected with ...

A group of renal pathologists, nephrologists, and transplant surgeons met in Banff, Canada on August 2-4, 1991 to develop a schema for international standardization of nomenclature and criteria for the histologic diagnosis of renal allograft rejection. Development continued after the meeting and the schema was validated by the circulation of sets of slides for scoring by participant pathologists. In this schema intimal arteritis and tubulitis are the principal lesions indicative of acute ...

We have isolated and identified the infiltrating inflammatory cells from rejecting rat kidney allografts. The first host cells to appear in the graft, already a few hours after the transplantation, are monocytes and lymphocytes. Both T and B lymphocytes contribute to the infiltrate: at early stages of rejection most of the infiltrating lymphocytes have the high electrophoretic mobility of (resting) T cells, whereas later during the rejection most of the infiltrating lymphocytes display ...

Chronic rejection has several histological appearances, depending on the type of organ graft. Common to all of them is transplant arteriosclerosis associated with an ongoing inflammatory response in the transplanted graft. To the contrary of classical atherosclerosis, in which the manifestations are mostly focal, proximal, and asymmetric, transplant arteriosclerosis is generalized, and the intimal thickening is concentric. In this article, we describe an experimental animal model whereby ...