PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Cell Tracking”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources
PubMed2003

Apolipoprotein E (apoE) uptake and distribution in mammalian cell lines is dependent upon source of apoE and can be monitored in living cells.

As part of investigations of the cellular uptake of apolipoprotein E (apoE) relevant to Alzheimer's disease we have found that different preparations of apoE are handled differently by cells expressing the LDL-receptor. Comparing recombinant, cellular and native apoE, complexed with different preparations of lipid we find that only cellular and native apoE enter a vesicular compartment. Some, but not all of these apoE containing vesicles are lysosomes. In order to further examine the intracellular fate of apoE we demonstrate that apoE-Enhanced green fluorescent protein chimeric protein can be taken up from medium by recipient cells and tracked within these cells for extended periods.

Animals↗
PubMed2004

Tracking metastatic tumor cell extravasation with quantum dot nanocrystals and fluorescence emission-scanning microscopy.

Metastasis is an impediment to the development of effective cancer therapies. Our understanding of metastasis is limited by our inability to follow this process in vivo. Fluorescence microscopy offers the potential to follow cells at high resolution in living animals. Semiconductor nanocrystals, quantum dots (QDs), offer considerable advantages over organic fluorophores for this purpose. We used QDs and emission spectrum scanning multiphoton microscopy to develop a means to study extravasation in vivo. Although QD labeling shows no deleterious effects on cultured cells, concern over their potential toxicity in vivo has caused resistance toward their application to such studies. To test if effects of QD labeling emerge in vivo, tumor cells labeled with QDs were intravenously injected into mice and followed as they extravasated into lung tissue. The behavior of QD-labeled tumor cells in vivo was indistinguishable from that of unlabeled cells. QDs and spectral imaging allowed the simultaneous identification of five different populations of cells using multiphoton laser excitation. Besides establishing the safety of QDs for in vivo studies, our approach permits the study of multicellular interactions in vivo.

Animals↗
PubMed2003

Liver metastasis of cancer facilitated by chemokine receptor CCR6.

When injected subcutaneously, mouse plasmacytoma (MOPC315) grew rapidly in situ, and metastatic cells became detectable first in the lymph nodes (LNs) and bone marrow, and later in the liver and lungs. We studied MOPC315 cell migration by tracking metastatic cells labelled with green fluorescent protein (GFP). We measured the levels of their chemokine receptor mRNA (by semiquantitative and real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), because chemokines can regulate organ predilection of metastasis. Freshly sorted metastatic cells and tumour cell lines derived from the liver of BALB/c mice overexpressed functional CCR6 and CCR7 molecules compared with primary tumour. Preincubation with the CCR6 ligand (CCL20) induced liver-sorted tumour cells to preferentially colonize the liver, demonstrating an association between liver metastasis and CCR6 expression in the mouse. Because the liver is a common site for metastasis, second only to draining LNs, we wished to ascertain whether this finding could be generalized, i.e. whether other cancers can use the similar mechanism of metastasis to the liver, and whether it holds true for humans. We found that CCR6 is overexpressed in small liver metastases of colon, thyroid and ovarian carcinomas compared with normal liver. Because human liver constitutively expresses CCL20, it could attract and select CCR6+ cancer cells. We suggest that chemotaxis via CCR6 might be a common mechanism by which malignant cancers metastasize to the liver. As metastasis in patients with cancer poses the biggest peril for survival, inhibition of CCR6 signalling, either during or after medical or surgical treatment, might be useful in preventing liver metastasis.

Animals↗
PubMed2004

In vivo tracking of T cell development, ablation, and engraftment in transgenic zebrafish.

Transgenic zebrafish that express GFP under control of the T cell-specific tyrosine kinase (lck) promoter were used to analyze critical aspects of the immune system, including patterns of T cell development and T cell homing after transplant. GFP-labeled T cells could be ablated in larvae by either irradiation or dexamethasone added to the water, illustrating that T cells have evolutionarily conserved responses to chemical and radiation ablation. In transplant experiments, thymocytes from lck-GFP fish repopulated the thymus of irradiated wild-type fish only transiently, suggesting that the thymus contains only short-term thymic repopulating cells. By contrast, whole kidney marrow permanently reconstituted the T lymphoid compartment of irradiated wild-type fish, suggesting that long-term thymic repopulating cells reside in the kidney.

Animals↗
PubMed2003

Tracking the errant cell after the atomic bombings: what went wrong?

Epidemiological data collected after the atomic-bomb blasts of Hiroshima and Nagasaki have established a link between radiation exposure and human cancer development and are the major source of information for current radiation-induced cancer risk assessment. To determine the mechanistic basis for radiation carcinogenesis, retrospective molecular analyses of archival hepatocellular carcinoma tissues from the atomic-bomb survivors were conducted. The tumor suppressor genes p53 and M6P/IGF2r were examined. HCC cases had either p53 mutations or M6P/IGF2r mutations, but rarely both. Moreover, the frequency of cases with M6P/ IGF2r mutations actually decreased with dose, while those for p53 increased. This implies two independent selection processes leading to liver cancer and that in radiation-induced HCC tumors the spectrum of molecular changes is different from that in "background" tumors.

Carcinoma, Hepatocellular↗
PubMed1989

Microcomputer-based interactive tracking of blood cells at biomaterial surfaces.

A microcomputer-based system for analyzing the motion of human platelets and leukocytes at synthetic surfaces from a sequence of video frames on tape is described. The software is designed to provide convenient interaction with an operator to reduce the burden of manual analysis. In addition, the system computes and stores the cell movement data on disk for subsequent statistical analysis. Measurement include the number and nature of cell-to-surface collisions, residence times, and distances traveled.

Biocompatible Materials↗
PubMed1987

Tracking of mouse cell lineage using microinjected DNA sequences: analyses using genomic Southern blotting and tissue-section in situ hybridizations.

We examined the feasibility of applying DNA microinjection to label cells for lineage studies of mouse embryos. Tissues from three transgenic mice mosaic due to the insertion of an exogenously introduced mouse beta-major globin gene were analyzed by genomic Southern-blotting and in situ hybridization. These studies allowed the direct quantification and localization of lineage descendants derived from the marked or transformed founder cells. The results of these studies suggested an early segregation of cells in the somatic vs. germ-cell lineages. The in situ hybridization data further demonstrated that cells of the transformed lineages were usually finely dispersed, indicative of extensive cell-cell mixing during mouse development. However, a notable exception to this was the patchy distribution of cells in the kidney (corresponding to individual nephrons), the clustering of transformed cells in individual villi of the small intestine, and the segregation of positive and negative seminiferous tubules in the testis. These data suggest a clonal basis for the organization of development in organs like the kidney, intestine, and testis.

Animals↗
PubMedDate not supplied

Evaluation of methods for estimating renal medullary blood flow.

Although only 10-15% of renal blood flow enters the medulla, renal medullary hemodynamics have been implicated as a key factor for the ability of the kidney to excrete concentrated or diluted urine and to be involved in sodium homeostasis. Due to the obvious importance of medullary hemodynamics, several methods have been developed or modified for estimating regional renal blood flow. The aim of the present paper is to evaluate critically the most commonly used methods available today. Those which are considered in this paper are: (1) albumin accumulation (Lilienfield), (2) rubidium-86 uptake, (3) transit time-indicator dilution, (4) red cell velocity tracking, (5) red cell flux (fluorescently labeled red cells) and (6) laser-Doppler flowmetry. Depending on the method of choice, the reported control values for renal medullary blood flow differ up to tenfold. Overall, it appears that the discrepancies in values obtained from the different methods will not be resolved until the methods are compared directly in the same animal and during different experimental conditions. Furthermore, one needs to understand and describe accurately the involved errors so that proper corrections can be made. It seems likely, however, that the majority of the techniques can be used to study relative changes, but attempts should not be made to draw conclusions about the absolute flow value. In this regard, the laser-Doppler method seems to be superior in its simplicity of use and its large advantage of continuous and relatively noninvasive measurement.

Animals↗
PubMed2005

T cell epitope immunotherapy induces a CD4+ T cell population with regulatory activity.

BACKGROUND: Synthetic peptides, representing CD4(+) T cell epitopes, derived from the primary sequence of allergen molecules have been used to down-regulate allergic inflammation in sensitised individuals. Treatment of allergic diseases with peptides may offer substantial advantages over treatment with native allergen molecules because of the reduced potential for cross-linking IgE bound to the surface of mast cells and basophils. METHODS AND FINDINGS: In this study we address the mechanism of action of peptide immunotherapy (PIT) in cat-allergic, asthmatic patients. Cell-division-tracking dyes, cell-mixing experiments, surface phenotyping, and cytokine measurements were used to investigate immunomodulation in peripheral blood mononuclear cells (PBMCs) after therapy. Proliferative responses of PBMCs to allergen extract were significantly reduced after PIT. This was associated with modified cytokine profiles generally characterised by an increase in interleukin-10 and a decrease in interleukin-5 production. CD4(+) cells isolated after PIT were able to actively suppress allergen-specific proliferative responses of pretreatment CD4(neg) PBMCs in co-culture experiments. PIT was associated with a significant increase in surface expression of CD5 on both CD4(+) and CD8(+) PBMCs. CONCLUSION: This study provides evidence for the induction of a population of CD4(+) T cells with suppressor/regulatory activity following PIT. Furthermore, up-regulation of cell surface levels of CD5 may contribute to reduced reactivity to allergen.

Allergens↗