16 research outputs found
What Is Direct Allorecognition?
Direct allorecognition is the process by which
donor-derived major histocompatibility complex (MHC)-peptide
complexes, typically presented by donor-derived âpassengerâ
dendritic cells, are recognised directly by recipient T cells.
In this review, we discuss the two principle theories which
have been proposed to explain why individuals possess a
high-precursor frequency of T cells with direct allospecificity
and how self-restricted T cells recognise allogeneic MHCpeptide
complexes. These theories, both of which are supported
by functional and structural data, suggest that T cells
recognising allogeneic MHC-peptide complexes focus either
on the allopeptides bound to the allo-MHC molecules or the
allo-MHC molecules themselves. We discuss how direct
alloimmune responses may be sustained long term, the consequences
of this for graft outcome and highlight novel strategies
which are currently being investigated as a potential
means of reducing rejection mediated through this pathway
Review of Technology: Planning for the Development of Telesonography
Teleradiology allows contemporaneous interpretation of imaging exams performed at some distance from the interpreting radiologist. The transmitted images are usually static. However, there is benefit to real-time review of full-motion ultrasound (US) exams as they are performed. Telesonography is transmission of full-motion sonographic data to a remote site. We hypothesize that US exams, read after having been compressed utilizing Motion Picture Experts Group version 4 (MPEG-4) compression scheme, transmitted over the Internet as streaming multimedia, decompressed, and displayed, are equivalent in diagnostic accuracy to reading the examinations locally. MPEG-4 uses variable compression on each image frame to achieve a constant output bit rate. With less compression, the bit rate rises, and the only way the encoder can contain bit rate within the set bandwidth is by lowering frame rate or reducing image quality. We review the relevant technologies and industry standard components that will enable low-cost telesonography