Effects of retinal laser photocoagulation on photoreceptor basic fibroblast growth factor and survival

PURPOSE: In an unpublished study, the authors found that immunoreactivity for basic fibroblast growth factor (bFGF) is increased in rod photoreceptors adjacent to long-standing laser burns in human diabetic retinas. The goal of this study was to determine whether laser photocoagulation produces a similar increase in photoreceptor bFGF and promotes survival of these cells in dystrophic rodent retinas. METHODS: Threshold (whitening) and subthreshold (nonwhitening) laser burns were made in retinas of normal and Royal College of Surgeons (RCS) rats and normal and rds mice. The retinas were processed for immunocytochemical and morphometric analyses. RESULTS: In nonlasered normal rat and mouse retinas, bFGF immunoreactivity was prominent in the nuclei of Müller cells and astrocytes. Photoreceptors were bFGF negative except for a zone of bFGF-immunoreactive rods near the ora serrata. Some photoreceptors in nonlasered retinas of RCS rats and rds mice became bFGF immunoreactive. After laser treatment, bFGF immunoreactivity was markedly increased in all photoreceptors flanking the threshold burns and within the subthreshold burns in normal and mutant rats and mice. In RCS rat retinas, photoreceptor bFGF immunoreactivity remained elevated within subthreshold burns and flanking the threshold burns, and photoreceptor survival was prolonged. In rds mouse retinas, increased bFGF immunoreactivity in photoreceptors was not sustained and their degeneration was not retarded. CONCLUSIONS: Laser treatment of RCS rat retinas produced a sustained increase in bFGF immunoreactivity in photoreceptors and prolonged their survival, but laser treatment of rds mouse retinas did not have a long-term effect on photoreceptor bFGF immunoreactivity or survival. Although species differences in laser effects on photoreceptor bFGF and survival are apparent, the finding that rods flanking laser burns in human retinas have sustained increases in bFGF immunoreactivity suggests that laser treatment may be useful for prolonging survival of mutant photoreceptors in retinas of patients with retinitis pigmentosa.     

Interleukin-1 in multiple myeloma: producer cells and their role in the control of IL-6 production

We studied the role of interleukin (IL)-1beta in patients with multiple myeloma. By in situ hybridization and immunochemistry, myeloid and megakaryocytic cells expressed high levels of the IL-1beta gene and produced IL-1beta. Myeloma cells less potently expressed the IL-1beta gene and IL-1beta protein. IL-1beta gene expression was not constitutive since it was detected in the bone marrow myeloma cells of two patients, unlike circulating tumoural cells. In addition, nine myeloma cell lines failed to express the IL-1beta gene and this expression could not be induced by 12 different cytokines. We demonstrated that IL-1 was mainly responsible for IL-6 production in the tumoural environment through a PGE2 loop. In fact, an IL-1 receptor antagonist (IL-1RA) blocked PGE2 synthesis and IL-6 production by 80%; this blockage could be reversed by adding synthetic PGE2. Similar findings were found with indomethacin, an inhibitor of cyclooxygenase that blocks PGE2 synthesis. Taken together, these data emphasize the possibility of blocking IL-1 by using IL-1RA or other antagonists in order to block IL-6 production, which is a major tumoural survival and proliferation factor.     

Technical advances in digital audio radio broadcasting

The move to digital is a natural progression taking place in all aspects of broadcast media applications from document processing in newspapers to video processing in television distribution. This is no less true for audio broadcasting which has taken a unique development path in the United States. This path has been heavily influenced by a combination of regulatory and migratory requirements specific to the U.S. market. In addition, competition between proposed terrestrial and satellite systems combined with increasing consumer expectations have set ambitious, and often changing, requirements for the systems. The result has been a unique set of evolving requirements on source coding, channel coding, and modulation technologies to make these systems a reality. This paper outlines the technical development of the terrestrial wireless and satellite audio broadcasting systems in the U.S., providing details on specific source and channel coding designs and adding perspective on why specific designs were selected in the final systems. These systems are also compared to other systems such as Eureka-147, DRM, and Worldspace, developed under different requirements.     

On computing the spectral radius of the Hankel plus Toeplitzoperator

The square root of the spectral radius of the Hankel plus Toeplitz operator has been shown to be the achievable performance of the mixed-sensitivity H^∞ design. The computation of the spectral radius is the bottleneck in the synthesis of the H ^∞ controller. In this paper, the spectral properties of the Hankel plus Toeplitz operator are investigated. A finite procedure for computing the spectral radius of the Hankel plus Toeplitz operator is proposed     

Effects of tumor necrosis factor of TMJ in temporomandibular joint disturbance syndrome

The synovial fluids from 17 cases of TMJ disturbance syndrome (TMJDS) and 5 normal persons were studied. The results show that TNF present in the synovial fluid of TMJDS patients. There is no significant difference between the cases of internal derangement and osteoarthritis. The concentration of TNF is associated with the bone destruction, local pain, open limit and the illness period. The authors consider that the TNF may take part in the autoimmunity of this disease and the destructive process of articular tissues.     

Relationship between autoregressive model coefficients of EMG and its potentials of jaw closing muscles at rest position and clenching

At rest position and varied clenching levels at intercuspal position, autoregressive (AR) models of myoelectrical activities of both masseter and anterior temporal muscles of 11 healthy subjects with intact natural dentitions were established. The relationship between the AR model coefficients of surface EMGs and their potentials was analyzed by multiple linear regression. It was found that the fourth order coefficient of AR had the greatest effect on the EMG potential levels and their relationship was positive in all recorded muscles. The results indicate the AR coefficients may become a characteristic parameter to describe myoelectrical activity of jaw closing muscles.