Differential acetylcholine and GABA release from cultured chick retina cells

In the present work we investigated the mechanisms controlling the release of acetylcholine (ACh) and of gamma-aminobutyric acid (GABA) from cultures of amacrine-like neurons, containing a subpopulation of cells which are simultaneously GABAergic and cholinergic. We found that 81.2 +/- 2.8% of the cells present in the culture were stained immunocytochemically with an antibody against choline acetyltransferase, and 38.5 +/- 4.8% of the cells were stained with an antibody against GABA. Most of the cells containing GABA (87.0 +/- 2.9%) were cholinergic. The release of acetylcholine and GABA was mostly Ca2+-dependent, although a significant release of [3H]GABA occurred by reversal of its transporter. Potassium evoked the Ca2+-dependent release of [3H]GABA and [3H]acetylcholine, with EC50 of 31.0 +/- 1.0 mm and 21.6 +/- 1.1 mm, respectively. The Ca2+-dependent release of [3H]acetylcholine was significantly inhibited by 1 micrometer tetrodotoxin and by low (30 nm) omega-conotoxin GVIA (omega-CgTx GVIA) concentrations, or by high (300 nm) nitrendipine (Nit) concentrations. On the contrary, the release of [14C]GABA was reduced by 30 nm nitrendipine, or by 500 nm omega-CgTx GVIA, but not by this toxin at 30 nm. The release of either transmitters was unaffected by 200 nm omega-Agatoxin IVA (omega-Aga IVA), a toxin that blocks P/Q-type voltage-sensitive Ca2+ channels (VSCC). The results show that Ca2+-influx through omega-CgTx GVIA-sensitive N-type VSCC and through Nit-sensitive L-type VSCC induce the release of ACh and GABA. However, the significant differences observed regarding the Ca2+ channels involved in the release of each neurotransmitter suggest that in amacrine-like neurons containing simultaneously GABA and acetylcholine the two neurotransmitters may be released in distinct regions of the cells, endowed with different populations of VSCC.     

Changes in bacterial species composition in enrichment cultures with various dilutions of inoculum as monitored by denaturing gradient gel electrophoresis

Denaturing gradient gel electrophoresis revealed changes in the bacterial species obtained from enrichment cultures with different inoculum dilutions. This inoculum dilution enrichment approach may facilitate the detection and isolation of a greater number of bacterial species than traditional enrichment techniques.     

The role of oncostatin M in animal and human connective tissue collagen turnover and its localization within the rheumatoid joint

OBJECTIVE: To study the interaction of interleukin-1alpha (IL-1alpha) and oncostatin M (OSM) in promoting cartilage collagen destruction. METHODS: Bovine, porcine, and human cartilage and human chondrocytes were studied in culture. The levels of collagenase (matrix metalloproteinase 1 [MMP-1]) and tissue inhibitor of metalloproteinases 1 (TIMP-1) were measured by bioassay and enzyme-linked immunosorbent assay (ELISA). The levels of OSM in rheumatoid synovial fluid were measured by ELISA. RESULTS: When combined with OSM, IL-1alpha, IL-1beta, and tumor necrosis factor alpha released proteoglycan and collagen from cartilage. OSM was the only member of the IL-6 family to have this effect. Human tendon also responded to IL-1alpha and OSM. OSM increased the production of MMP-1 and TIMP-1 but when combined with IL-1alpha, synergistically promoted MMP-1 production in human chondrocytes and synovial fibroblasts. High levels of OSM were found in human rheumatoid synovial fluids, and confocal microscopy showed that OSM was produced by macrophages in rheumatoid synovial tissue. CONCLUSION: These results highlight an important new mechanism by which there is irreversible loss of collagen from cartilage.     

Mesenteric venous thrombosis after appendicectomy in a child: clinical case and review of the literature

Mesenteric venous thrombosis (MVT) after appendicectomy has not been reported in the pediatric literature. This complication is associated with significant morbidity and mortality rates in adults. The report of this case attempts to analyze the features found in an appendicectomized child documented by radiological examination and surgery before and after starting heparin therapy. Anticoagulation treatment should be started as soon as possible and continued for a long time to decrease the risk of relapse.     

Segmentation by Continuous Latent Semantic Analysis for Multi-structure Model Fitting

International Journal of Computer Vision - In this paper, we propose a novel continuous latent semantic analysis fitting method, to efficiently and effectively estimate the parameters of model...     

Prevention of deposition and agglomeration of particles in suspensions used for direct absorption of concentrated solar radiation

In direct absorption of solar radiation for industrial purposes, by micron-size graphite particles suspended in nitrogen gas, agglomeration and deposition of these particles are the major problems. This paper discusses two methods for limitation of agglomeration and deposition. The first is to create a thermal repulsion force between the suspension and the surface to keep the particles away. The second is the surface coating of the particles with a very thin silicon-base layer of molecular order.

Theoretical calculations showed that the first method required an impracticably high temperature gradient. The second method reduced the risk of deposition by about five times while negligible change occurred in the size distribution of the particles.     

Production of human normal adult and fetal hemoglobins in Escherichia coli

A hemoglobin expression system in Escherichia coli is described. In order to produce authentic human hemoglobin, we need to co-express both methionine aminopeptidase and globin genes under the control of a strong promoter. We have constructed three plasmids, pHE2, pHE4 and pHE7, for the expression of human normal adult hemoglobin and a plasmid, pHE9, for the expression of human fetal hemoglobin, in high yields. The globin genes can be derived from either synthetic genes or human globin cDNAs. The extra amino-terminal methionine residues of the expressed globins can be removed by the co-expressed methionine aminopeptidase. The heme is inserted correctly into the expressed alpha- globin from our expression plasmids. A fraction (approximately 25%) of the heme is not inserted correctly into the expressed beta- or gamma- globin. However, the incorrectly inserted hemes can be converted into the correct conformation by carrying out a simple oxidation-reduction process on the purified hemoglobin molecule. We have investigated the functional properties of the expressed hemoglobins by measuring their oxygen-binding properties and their structural features by obtaining their 1H-NMR spectra. Our results show that authentic human normal adult and fetal hemoglobins can be produced from our expression plasmids in E. coli and in high yields. Our expression system allows us to design and to produce any recombinant hemoglobins needed for our research on the structure-function relationship in hemoglobin.      

Object detection by global contour shape

We present a method for object class detection in images based on global shape. A distance measure for elastic shape matching is derived, which is invariant to scale and rotation, and robust against non-parametric deformations. Starting from an over-segmentation of the image, the space of potential object boundaries is explored to find boundaries, which have high similarity with the shape template of the object class to be detected. An extensive experimental evaluation is presented. The approach achieves a remarkable detection rate of 83-91% at 0.2 false positives per image on three challenging data sets.