The role of low-frequency ultrasound in the combined treatment of alveolitis]

The authors claim that combined use of a special therapeutic paste and low-frequency ultrasound for therapy of alveolitis help reduce the number of visits to a dentist and shorten the treatment duration. Fifteen patients were treated by this method. They had to visit the dentist two times less and the number of invalidity days was less by 2.2 days, on an average.     

Shape bistability of a membrane neck: a toggle switch to control vesicle content release

Shape dynamics and permeability of a membrane neck connecting a vesicle and plasma membrane are considered. The neck is modeled by a lipid membrane tubule extended between two parallel axisymmetric rings. Within a range of lengths, defined by system geometry and mechanical properties of the membrane, the tubule has two stable shapes: catenoidal microtubule and cylindrical nanotubule. The permeabilities of these two shapes, measured as ionic conductivity of the tubule interior, differ by up to four orders of magnitude. Near the critical length the transitions between the shapes occur within less than a millisecond. Theoretical estimates show that the shape switching is controlled by a single parameter, the tubule length. Thus the tubule connection can operate as a conductivity microswitch, toggling the release of vesicle content in such cellular processes as "kiss-and-run" exocytosis. In support of this notion, bistable behavior of membrane connections between vesicles and the cell plasma membrane in macrophages is demonstrated.     

Regulatory functions of alloreactive Th2 clones in human renal transplant recipients

BACKGROUND: Chronic allograft rejection is the major clinical problem in organ transplantation. There is evidence that indirect T cell recognition of donor-specific HLA peptides may play an important role in the immunopathogenesis of chronic allograft rejection. We have recently shown that HLA allopeptide-specific T cell clones generated from renal transplant recipients with chronic allograft nephropathy are of the Th1 phenotype, while those from stable patients are Th2. There is evidence in experimental animal models of autoimmunity and transplantation that Th2 cells may function to regulate immune responses, but the biological relevance of these observations in humans has not been reported. METHODS: The purpose of this study was to investigate the putative regulatory functions of alloreactive human Th2 clones. HLA-DR allopeptide-specific Th1 and Th2 cell clones were generated from peripheral blood lymphocytes of human renal allograft recipients with chronic allograft nephropathy (CAN) or with stable renal function (SRF), respectively. RESULTS: An in vitro co-culture system showed that the proliferative responses of Th1 clones from patients with CAN were significantly inhibited by the Th2 clones in response to the donor-derived HLA allopeptides. In addition, co-culture of the Th2 clones inhibited cytokine production (IFN-gamma) by the Th1 clones in response to the donor-specific peptides. The regulatory functions of Th2 clones were antigen-specific since they only occurred when both the Th1 and Th2 clones were reactive to the same HLA-DR allopeptide, and were mediated by IL-4 and IL-10. CONCLUSIONS: This is the first demonstration, to our knowledge, indicating that Th2 cells may function to regulate indirect Th1 alloimmune responses that are critical for the progression of CAN in humans.     

The role of the graft endothelium in transplant rejection: evidence that endothelial activation may serve as a clinical marker for the development of chronic rejection

In this review, we discuss the role of the allograft endothelium in the recruitment and activation of leukocytes during acute and chronic rejection. We discuss associations among endothelial activation responses, the expression of adhesion molecules, chemokines and chemokine receptors, and rejection; and we propose that endothelial vascular cellular adhesion molecule-1 (VCAM-1) may be used as a surrogate marker of acute rejection and allograft vasculopathy. In addition, we describe potential mechanistic interpretations of persistent endothelial cell (EC) expression of major histocompatibility complex (MHC) class II molecules in allorecognition. The graft endothelium may provide an antigen-specific signal to transmigrating, previously activated, T cells and may induce B7 expression on locally transmigrating leukocytes to promote costimulation. Taken together, these functions of the EC provide it with a potent regulatory role in rejection and in the maintenance of T-cell activation via the direct and/or the indirect pathways of allorecognition.