PubMed · 13288878
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
C WASASTJERNA, W NYBERG. 1956-01-12. A micro-hematocrit method.. https://pubmed.ncbi.nlm.nih.gov/13288878/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The possibility of measuring a full Doppler flow depth profile in parallel by use of frequency-domain optical coherence tomography is demonstrated. The method is based on a local phase analysis of the backscattered signal and allows for imaging of bidirectional Doppler flow. The Doppler frequency limit is 5 kHz for the presented measurements and is set by half of the frame rate of the CCD detector array. We measured the flow of 0.3-microm microspheres suspended in distilled water at controlled flow rates and in vitro human blood flow through a 200-microm capillary with a real-time color-encoded Doppler tomogram rate of 2-3/s.
It appears that there are two classes of human circulating endothelial cell (EC) progenitors, CD34+ and CD34-CD14+ cells. Attention has focused on CD34+ cells, yet CD34-CD14+ monocytic cells are far more abundant and may represent the most common class of circulating EC progenitor. Little is known about molecular or physiological factors that regulate putative CD34-CD14+ EC progenitor function, although factors secreted by other blood and cardiovascular cells to which they are exposed probably affect their behavior. Hypoxia and stretch are two important physiological stimuli known to trigger growth factors in cardiovascular cells and accordingly may modulate EC progenitors. To investigate the impact of these environmental parameters on EC progenitors, EC production in CD34-CD14+ cultures was evaluated. Our data indicate that neither stretch nor hypoxia alters EC production by EC progenitors directly but do so indirectly through their effects on cardiovascular cells. Conditioned media (CM) from coronary artery smooth muscle cells inhibit EC production in culture, and this inhibition is stronger if the coronary smooth muscle cells have been subjected to cyclic stretch. In contrast, cardiomyocyte CM increases EC cell number, an effect that is potentiated if the myocytes have been subjected to hypoxia. Significantly, EC progenitor responses to CM are altered by the presence of CD34-CD14- peripheral blood mononuclear cells (PBMCs). Moreover, CD34-CD14- PBMCs attenuate EC progenitor responsiveness to the angiogenic factors basic fibroblast growth factor (FGF-2), vascular endothelial cell growth factor-A165, and erythropoietin while inducing EC progenitor death in the presence of transforming growth factor-beta1 in vitro
BACKGROUND: Quantitation of antigen-specific T cells provides an insight into the development and dynamics of T-cell responses in tumor immunology and infectious diseases. Soluble major histocompatibility class I tetramers are widely used to monitor immune responses; however, variations due to handling and analysis are likely to confound comparisons between different experiments and laboratories. METHODS: Whole blood from healthy donors was stained with HLA-A*0201/tetramers specific for an epitope of phosphoprotein 65, the immunodominant antigen in cytomegalovirus infection. With the help of Trucount tubes, a single-platform, four-color flow cytometric assay was established to obtain absolute counts of tetramer-positive cells. Various staining and gating strategies were evaluated. RESULTS: The no-wash method was a quick and straightforward procedure for the quantitation of tetramer-positive events from whole blood. The level for background staining was low. This information about the intra-assay-related variation and the physiologic variation will allow validation and interpretation of data in future studies. CONCLUSIONS: The method is highly reliable and can be standardized for multiple experiments. It is therefore suitable for the direct ex vivo analysis of antigen-specific T cells in a variety of clinical settings such as infectious, autoimmune, or neoplastic diseases and can be implemented as a tool for multicenter studies.