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Results for “Cell Tracking”

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At least 199 records · Page 11Linked to original sources

PubMed1996

Long-term hematopoietic culture-initiating cells are more abundant in mobilized peripheral blood grafts than in bone marrow but have a more limited ex vivo expansion potential.

Mobilized peripheral blood hematopoietic progenitor cells obtained from cancer patients treated with high-dose cyclophosphamide (7g/m2) followed by G-CSF, GM-CSF, IL-3, PIXY321, or combinations of these cytokines have been successfully used for autologous stem cell transplantation. We investigated the ability of hematopoietic progenitor cells (HPC) derived from mobilized peripheral blood (PB) to undergo ex vivo expansion in short term cultures by enumerating numbers of de novo generated CD34+ cells, assayable progenitor cells, and the frequency of long-term hematopoietic culture-initiating cells (LTHC-IC). These parameters were examined in CD34+ cells generated in culture through the use of cell tracking with the membrane dye PKH2. Fresh isolated mobilized CD34+ cells contained 0.49 +/- 0.36% LTHC-IC. However, due to the high number of total CD34+ cells in mobilized PB, the absolute number of LTHC-IC was higher than that contained in a bone marrow (BM) harvest. Mobilized CD34+ cells were stained with PKH2 and incubated with SCF, IL-3, and IL-6. After 5 to 6 days, numbers of total CD34+ cells and clonogenic progenitors increased 1.4- and 2.2-fold, respectively. Numbers of total progenitors continued to increase such that 10 to 12 days after the initiation of cultures a 6.4-fold increase was demonstrable. However, between days 5 and 7 of culture, the frequency of LTHC-IC in CD34+PKH2bright cells (cells which did not divide) was less than 50% of that determined for fresh cells, while the frequency among CD34+PKH2dim cells (cells that had divided) was very low or undetectable. However, moderately higher frequencies of LTHC-IC were detected following expansion for 48 hours only. In similar assays, both BM and cord blood cells were capable of generating LTHC-IC in CD34+PKH2dim cells but not to expand the overall number of these progenitors. These observations suggest that although mobilized PB CD34+ cells contain large numbers of LTHC-IC, these cells might not be capable of further ex vivo expansion and generation of additional LTHC-IC in vitro. Furthermore, these data indicate that mobilized PB CD34+ cells may have undergone maximal "in vivo expansion" such that additional ex vivo expansion of primitive progenitor cells may not be possible.

Antigens, CD34↗

PubMed1992

Effect of scatter factor and hepatocyte growth factor on motility and morphology of MDCK cells.

We investigated the effects of human placental scatter factor (hSF), mouse scatter factor (mSF) and recombinant human hepatocyte growth factor (HGF) on motility and morphology of individual Madin-Darby canine kidney cells using a computerized cell tracking system. All three factors increased the velocity of individual cells and the ratio of moving to stationary cells. Similarly, all three factors caused changes in morphologic features of cells, leading to increased area, flatness, and polarity. Increases in area and flatness but not polarity were slightly greater with HGF than with hSF or mSF. These results suggest that SFs and HGF have similar effects on motility and morphology of isolated epithelial cells.

Animals↗

PubMed2003

Labeling embryonic stem cells with enhanced green fluorescent protein on the hypoxanthineguanine phosphoribosyl transferase locus.

OBJECTIVE: To label embryonic stem (ES) cells with enhanced green fluorescent protein (EGFP) on the hypoxanthineguanine phosphoribosyl transferase (HPRT) gene locus for the first time to provide a convenient and efficient way for cell tracking and manipulation in the studies of transplantation and stem cell therapy. METHODS: Homologous fragments were obtained by polymerase chain reaction (PCR), from which the gene targeting vector pHPRT-EGFP was constructed. The linearized vector was introduced into ES cells by electroporation. The G418(r)6TG(r) cell clones were obtained after selection with G418 and 6TG media. The integration patterns of these resistant cell clones were identified with Southern blotting. RESULTS: EGFP expressing ES cells on the locus of HPRT were successfully generated. They have normal properties, such as karyotype, viability and differentiation ability. The green fluorescence of EGFP expressing cells was maintained in propagation of the ES cells for more than 30 passages and in differentiated cells. Cultured in suspension, the "green" ES cells aggregated and formed embryoid bodies, retaining the green fluorescence at varying developmental stages. The "green" embryoid bodies could expand and differentiate into various types of cells, exhibiting ubiquitous green fluorescence. CONCLUSIONS: This generation of "green" targeted ES cells is described in an efficient protocol for obtaining the homologous fragments by PCR. Introducing the marker gene in the genome of ES cells, we should be able to manipulate them in vitro and use them as vehicles in cell-replacement therapy as well as for other biomedical and research purposes.

Animals↗

PubMed1999

Real-time imaging of the dynamics of secretory granules in growth cones.

Secretory granules containing a hybrid protein consisting of the regulated secretory protein tissue plasminogen activator and an enhanced form of green fluorescent protein were tracked at high spatial resolution in growth cones of differentiated PC12 cells. Tracking shows that granules, unlike synaptic vesicles, generally are mobile in growth cones. Quantitative analysis of trajectories generated by granules revealed two dominant modes of motion: diffusive and directed. Diffusive motion was observed primarily in central and peripheral parts of growth cones, where most granules diffused two to four orders of magnitude more slowly than comparably sized spheres in dilute solution. Directed motion was observed primarily in proximal parts of growth cones, where a subset of granules underwent rapid, directed motion at average speeds comparable to those observed for granules in neurites. This high-resolution view of the dynamics of secretory granules in growth cones provides insight into granule organization and release at nerve terminals. In particular, the mobility of granules suggests that granules, unlike synaptic vesicles, are not tethered stably to cytoskeletal structures in nerve terminals. Moreover, the slow diffusive nature of this mobility suggests that secretory responses involving centrally distributed granules in growth cones will occur slowly, on a time scale of minutes or longer.

Animals↗

PubMed1998

The effects of delta rays on the number of particle-track traversals per cell in laboratory and space exposures.

It is a common practice to estimate the number of particle-track traversals per cell or cell nucleus as the product of the ion's linear energy transfer (LET) and cell area. This practice ignores the effects of track width due to the lateral extension of delta rays. We make estimates of the number of particle-track traversals per cell, which includes the effects of delta rays using radial cutoffs in the ionization density about an ion's track of 1 mGy and 1 cGy. Calculations for laboratory and space radiation exposures are discussed, and show that the LET approximation provides a large underestimate of the actual number of particle-track traversals per cell from high-charge and energy (HZE) ions. In light of the current interest in the mechanisms of radiation action, including signal transduction and cytoplasmic damage, these results should be of interest for radiobiology studies with HZE ions.

Cells↗

PubMed2006

Analysis and visualization of cell movement in the developing zebrafish brain.

Detailed reconstruction of the spatiotemporal history of embryonic cells is key to understanding tissue formation processes but is often complicated by the large number of cells involved, particularly so in vertebrates. Through a combination of high-resolution time-lapse lineage tracing and antibody staining, we have analyzed the movement of mesencephalic and metencephalic cell populations in the early zebrafish embryo. To facilitate the analysis of our cell tracking data, we have created TracePilot, a software tool that allows interactive manipulation and visualization of tracking data. We demonstrate its utility by showing novel visualizations of cell movement in the developing zebrafish brain. TracePilot (http://www.mpi-cbg.de/tracepilot) is Java-based, available free of charge, and has a program structure that allows the incorporation of additional analysis tools.

Animals↗

PubMed2002

Neural cells derived from adult bone marrow and umbilical cord blood.

Under experimental conditions, tissue-specific stem cells have been shown to give rise to cell lineages not normally found in the organ or tissue of residence. Neural stem cells from fetal brain have been shown to give rise to blood cell lines and conversely, bone marrow stromal cells have been reported to generate skeletal and cardiac muscle, oval hepatocytes, as well as glia and neuron-like cells. This article reviews studies in which cells from postnatal bone marrow or umbilical cord blood were induced to proliferate and differentiate into glia and neurons, cellular lineages that are not their normal destiny. The review encompasses in vitro and in vivo studies with focus on experimental variables, such as the source and characterization of cells, cell-tracking methods, and markers of neural differentiation. The existence of stem/progenitor cells with previously unappreciated proliferation and differentiation potential in postnatal bone marrow and in umbilical cord blood opens up the possibility of using stem cells found in these tissues to treat degenerative, post-traumatic and hereditary diseases of the central nervous system.

Adult↗

PubMed1997

Locomotory phenotypes of human tumor cell lines and T lymphocytes in a three-dimensional collagen lattice.

Active cellular locomotion is a feature of such diverse cell types as lymphocytes and cancer cells. The locomotory phenotype of a cell should ultimately reflect the biochemical basis of different migratory strategies. We investigated the locomotory behavior of five epithelial cell lines and one non-epithelial human cell-line as well as human CD4+ T lymphocytes in a three-dimensional collagen type I matrix using time-lapse video microscopy and computer assisted cell-tracking. Migration velocity was up to 70 times lower in tumor cells (0.1-0.3 microm/min) as compared to T lymphocytes (7-7.5 microm/min), whereas the percentage of spontaneously active cells was up to twice as high in tumor cells (80-90%) in comparison to T lymphocytes (54%). Persistence, i.e. the degree of roaming, varied appreciably between the different cell types. In conclusion, velocity and persistence may describe distinct migration strategies in different cell types, i.e. discerning T cell migration from tumor cell invasion.

Cell Movement↗

PubMed1996

The fate of self-reactive B cells depends primarily on the degree of antigen receptor engagement and availability of T cell help.

Self-reactive B cells from tolerant double-transgenic (Dbl-Tg) mice coexpressing hen egg lysozyme (HEL) and rearranged anti-HEL immunoglobulin genes have a relatively short life span when compared to normal B cells, irrespective of whether they are exposed to antigen in multivalent membrane-bound form (mHEL-Dbl-Tg mice) or soluble form (sHEL-Dbl-Tg mice). The factors responsible for determining the fate of these B cells after encounter with self-antigen were investigated using a cell-tracking technique in which anti-HEL Ig-Tg spleen cells were labeled with the intracellular dye 5-carboxyfluorescein diacetate-succinimidyl ester (CFSE) and injected either into non-Tg recipients or a variety of HEL-Tg hosts. In non-Tg recipients, HEL-binding B cells persisted in the circulation and could be detected in the follicles of the spleen for at least 5 d. On transfer into either mHEL-Tg or sHEL-Tg hosts, they underwent activation and then rapidly disappeared from the blood and spleen over the next 3 d, consistent with the short life span reported previously. Immunohistology of spleens from sHEL-Tg recipients indicated that the transferred B cells had migrated to the outer margins of the periarteriolar lymphoid sheath (PALS), where they were detectable for 24 h before being lost. The positioning of B cells in the outer PALS depended on a critical threshold of Ig receptor binding corresponding to a serum HEL concentration between 0.5 and 15 ng/ml, but was not restricted to endogenously expressed HEL in that the same migratory pattern was observed after transfer into non-Tg recipients given exogenous (foreign) HEL. Moreover, bone marrow-derived immature Ig-Tg B cells homed to the outer PALS of sHEL-Tg mice and then disappeared at the same rate as mature B cells, indicating that the stage of maturation did not influence the fate of self-reactive B cells in a tolerant environment. On the other hand, HEL-binding B cells transferred into sHEL-Dbl-Tg recipients persisted over the 3-d period of study, apparently due to insufficient availability of antigen, as indicated by the fact that the degree of Ig receptor downregulation on the transferred B cells was much less than in sHEL-Tg recipients. If T cell help was provided to Ig-Tg B cells at the time of transfer into sHEL-Tg recipients in the form of preactivated CD4+ T cells specific for major histocompatibility complex-peptide complexes on the B cell surface, HEL-binding B cells migrated through the outer PALS of the spleen to the follicle, where they formed germinal centers, or to adjacent red pulp, where they formed proliferative foci and secreted significant amounts of anti-HEL antibody. Taken together, these results indicated that the outcome of the interaction between self-antigen and B cells is largely determined by a combination of the degree of receptor engagement and availability of T cell help.

Amino Acid Sequence↗

PubMed2003

Direct visualization of a stratified epithelium reveals that wounds heal by unified sliding of cell sheets.

Observing cells in their original niche is a key link between the information gleaned from planar culture and in vivo physiology and pathology. A new approach combining the transparency of the cornea, Hoffman modulation optics, and digital imaging allowed movements of individual corneal cells to be viewed directly in situ. 3-Dimensional time-lapse movies imaging unstained cells within the stratified corneal epithelium during wound healing were made. Tracking cell movements dynamically provided a definitive answer to the long-standing question: does a stratified epithelium heal by "sliding" of cell sheets as a coherent unit or do individual cells "leap frog" each other at the wound margin? A wound in the corneal epithelium healed primarily by sliding of the whole epithelium, with approximately 95% of cells moving with similar speed and trajectories and with little change in their relative position. Only 5% of cells changed layers, with equal proportions moving up or down. Epithelial healing in situ occurred in three phases: a latency, migration, and reconstruction phase. This model provides a unique system to study the behaviors of individual cells in their original niche. It shows that cells slide into a wound as a unified unit to heal a stratified epithelium.

Animals↗

PubMed2005

3D culture model and computer-assisted videomicroscopy to analyze migratory behavior of noninvasive and invasive bronchial epithelial cells.

To date, most of the studies in the field of cell migration have been applied to two-dimensional (2D) models. To mimic the three-dimensional (3D) conditions similar to those observed in vivo during tumor invasion, we developed a 3D model of cell migration in which cells were embedded in a collagen I matrix placed in a double-compartment chamber. Using time-lapse videomicroscopy and interactive cell tracking in a four-dimensional data set, we determined the cell trajectories and their migration kinetics. We compared the 2D and 3D migratory behavior of a noninvasive cell line (16HBE) with the migratory behavior of an invasive cell line (BZR). Our results show that the 3D migration kinetics of the noninvasive cell line were lower than the migration kinetics of the invasive cell line. In contrast, in 2D models, no significant difference was observed between the two cell lines. To validate our 3D model, we further investigated the effect of epidermal growth factor (EGF), a promoter of tumor cell motility and invasion on the noninvasive cell line (16HBE). EGF increased significantly the migration kinetics of the noninvasive cell line. Our results show that the 3D model of cell migration allowed us to differentiate the migratory behavior of invasive and noninvasive cells and that such a model can help in the development of molecular targeted therapy as it approaches the in vivo conditions.

Bronchi↗

PubMed2005

[Myoblast transplantation for heart failure: where are we heading?].

Cell therapy in cardiology is already a reality, as evidenced by the number of ongoing clinical trials. These studies entail administration of either skeletal myoblasts in patients with severe ischemic left ventricular dysfunction or of bone marrow-derived cells in patients with acute myocardial infarction and in whom cell therapy is an adjunct to a percutaneous revascularization procedure. The techniques of preparation, expansion and storage of myoblasts are now quite effective. The problem is simpler for bone marrow cells as in most studies, the procedure is limited to an iliac crest biopsy followed by reinjection of the crude, unfractionated bone marrow, as routinely done in clinical haematology since many years. The results of these studies are not yet fully available. Some of them have been enthusiastically reported to be positive but should be interpreted cautiously because of the usually small sample sizes and the common lack of randomisation and double-blind assessment of outcomes. Thus, the fact that cell therapy has now become a reality should not lead to underscore the yet unsettled fundamental issue, i.e., the ability of this novel mode of therapy to truly regenerate areas of necrotic myocardium and restore function in once akinetic territories. From this standpoint, cell therapy is still a dream. Since the beginning, it has been clear that myoblasts were exclusively committed to differentiate into myotubes, without any evidence for a phenotypic conversion into cardiomyocytes. Although the debate is more controversial for bone marrow cells, the reliance on accurate genetic methods of cell tracking has led to increasingly challenge the purported plasticity of these cells. This by no means implies that cell therapy does not exert beneficial effects that could be mediated by alternate mechanisms like limitation of remodelling of paracrine effects. The basic point is that neither skeletal myoblasts nor bone marrow cells fulfill the major criteria required for a true cardiac regeneration: a coupling of the grafted cells with those of the recipient myocardium and the subsequent generation of a contractile force. It is therefore critical to go on exploring other paths, among which embryonic stem cells are particularly attractive.

Bone Marrow Cells↗

PubMedDate not supplied

Use of a rat cDNA probe specific for the Y chromosome to detect male-derived cells.

A cDNA probe that exhibits specificity for the rat Y chromosome was generated by using a set of primers specific to the murine Sry gene, the sex-determining region of the Y chromosome. A 459-base pair (bp) DNA fragment was obtained by polymerase chain reaction (PCR) amplification from male, but not female, rat genomic DNA (EMBL Nucleotide Sequence Database accession number X89730). This DNA fragment was purified, cloned using a vector, and digested with EcoR1 to yield a 270-bp DNA fragment. This 270-bp cDNA fragment, when used as a probe in Southern blot analysis of rat DNA, was observed to bind to three separate bands of approximately 2.3, 5.0, and 7.0 kb in size. The binding was demonstrated with male, but not female, genomic DNA. Another set of primers was generated to sequences within the 270-bp fragment that produced a PCR product of 104 bp. This DNA fragment, when used as a probe in Southern blot analysis, enabled PCR detection of at least 0.1% male cells in a mixed population of female cells. These cDNA probes should prove useful in studies designed to track cell populations (e.g., tumor metastasis and hemopoietic cells after bone marrow transplantation) in syngeneic male/female pairs. In addition, a cDNA probe that is specific for the rat Sry gene might be valuable in studies of fetal male sexual development or the study of spermiogenesis.

Animals↗

PubMed2006

[Tracking neural progenitor cells transplanted into rabbit spinal cord by detection of dopamine receptor 2 with positron emission computed tomography].

OBJECTIVE: To explore the effect of in vivo positron emission computed tomography (PET) in tracking the stem cells transplanted into spinal cord. METHODS: Telomerase-immortalized human neural progenitor cells of the line hNPC-TERT were cultured. HeLa cells were used as control cells. RT-PCR was used to detect the mRNA expression of dopamine receptor 2 (D(2)) in both cell lines. (3)H-raclopride was added into the suspensions of these 2 cell lines. RT-PCR was used to detect the mRNA expression of D(2), and immunofluorescent staining was conducted on the cells to detect the protein expression of D(2). Twenty-two New Zealand rabbits were randomly divided into 4 groups to undergo transplantation of hNPC-TERT cell suspension into the spinal cord at the segment T10, or transplantation of HeLa cells. Two day after the transplantation some rabbits were killed to take out the spinal cord at the segment T10 to undergo immunofluorescent staining to examine the radioactivity in the spinal cord. Some rabbits were injected with (11)C-raclopride intravenously and then underwent PET imaging. RESULTS: RT-PCR showed that mRNA expression was positive in the hNPC-TERT cells but negative in the HeLa cells, and immunofluorescent staining showed protein expression of D(2) in the in the hNPC-TERT cells and not in the HeLa cells. The spinal cords specimens taken 2 days after transplantation had human-specific nuclear (HN) antigen positive and D(2) positive cells. Fluorescent microscopy showed that the hNPC-TERT cells in the injection site did not migrate remarkably; and showed that the D(2) staining was negative and HN antigen was positive in the HeLa cells. (11)C-raclopride PET imaging of the live rabbits showed accumulation of radioactivity at the hNPC-TERT cell injection site with a standard uptake value significantly higher than that of the HeLa cell transplantation group (P < 0.01). (11)C-raclopride PET imaging of the isolated spinal cords showed rounded focal image of increased radioactivity in the hNPC-TERT cell transplantation group and linear image of radioactivity without clear border in the HeLa cell transplantation group. CONCLUSION: PET imaging with as radiotracer targeting at specific cellular marker is effective in tracking cells into the body and in vivo visual evaluation of stem cell transplantation.

Animals↗

PubMed1998

CD4+ T lymphocytes migrating in three-dimensional collagen lattices lack focal adhesions and utilize beta1 integrin-independent strategies for polarization, interaction with collagen fibers and locomotion.

Cell migration may depend on integrin-mediated adhesion to and deadhesion from extracellular matrix ligands. This concept, however, has not yet been confirmed for T lymphocytes migrating in three-dimensional extracellular matrices. We investigated receptor involvement in T cell migration combining a three-dimensional collagen matrix model with time-lapse videomicroscopy, computer-assisted cell tracking and confocal microscopy. In collagen lattices, the migration of CD4+ T cells (1) involved interactions with collagen fibers at the leading edge and uropod likewise, (2) occurred independently of the co-clustering of beta1, beta2, or beta3 integrins with F-actin, focal adhesion kinase, and phosphotyrosine at interactions with collagen fibers, (3) was counteracted by high-affinity beta1 integrin binding induced by antibody TS2/16; however, (4) the migration could not be blocked by a combination of adhesion-perturbing anti-beta1, -beta2, -beta3, and alpha v integrin antibodies. Integrin blocking neither affected cell polarization, interaction with fibers, beta1 integrin distribution, migration velocity, path structure, nor the number of locomoting cells in spontaneously migrating or concanavalin A-activated cells. Hence, T lymphocytes migrating in three-dimensional collagen matrices may utilize highly transient interactions with collagen fibers of low adhesivity, thereby differing from focal adhesion-dependent migration strategies employed by other cells.

Antibodies, Monoclonal↗

PubMed2006

Dendritic morphogenesis of cerebellar Purkinje cells through extension and retraction revealed by long-term tracking of living cells in vitro.

Cerebellar Purkinje cells have the most elaborate dendritic trees among the neurons in the CNS. To investigate the dynamic aspects of dendritic morphogenesis of Purkinje cells, we performed a long-term analysis of living cells in cerebellar cell cultures derived from glutamate decarboxylase 67-green fluorescent protein mice. Most Purkinje cells had several primary dendrites during the 25-day culture period. Repeated observation of green fluorescent protein-expressing Purkinje cells over a period of 10-25 days in vitro demonstrated that not only extension, but also retraction of primary dendrites occurred during this culture period. Interestingly, both extension and retraction of primary dendrites were active between 10 and 15 days in vitro, and retraction of a primary dendrite occurred concomitantly with elongation of other primary dendrites in the same cell. Analysis of the morphological characteristics of the retracted primary dendrites demonstrated that shorter and less branched primary dendrites tended to retract. Furthermore, treatment with an inhibitor of calcium/calmodulin-dependent protein kinase II reduced the number of primary dendrites specifically during 5-15 days in vitro, the culture period when the extension and retraction of primary dendrites occurred actively. Blockade of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate-type glutamate receptors also reduced the number of primary dendrites during the same culture period, while inhibition of glutamate transporters increased the number. These findings suggest that the final morphology of Purkinje cells is achieved not only through extension, but also through retraction of their dendrites, and that calcium/calmodulin-dependent protein kinase II and neuronal activity are involved in this dendritic morphogenesis.

Animals↗

PubMedDate not supplied

Evaluation of eluents from separations of CD34+ cells from human cord blood using a commercial, immunomagnetic cell separation system.

Human CD34+ cells from cord blood were separated in a two-step process using a commercial, immunomagnetic cell retention system. The performance of the system was evaluated by analyzing a number of eluents from the separations with a number of analytical techniques. In addition to cell counts and flow cytometry analysis, a new experimental technique that is undergoing development, cell tracking velocimetry (CTV), was used. CTV measures the degree to which a cell is immunomagnetically labeled, known as the magnetophoretic mobility, of a population of cells on a cell-by-cell basis and presents the results in the form of a histogram similar to flow cytometry data. The average recovery and purity of CD34+ cells from 10 separations was 52% and 60%, respectively. CTV analysis indicated that the mean magnetophoretic mobility of the positively enriched CD34 cells was 9.64 x 10(-5) mm3/T-A-s, while the mean mobility from negative eluents was -2.02 x 10(-6) mm3/T-A-s, very similar to the mobility of unlabeled cells. Within the positive eluents, the range of magnetophoretic mobility was approximately 50-fold, representing a plausible 50-fold range in surface CD34 antigen expression. CTV analysis also indicated that in some separations, positive cells were not retained by the immunomagnetic cell retention system. Finally, preliminary studies indicate that monocytes might be a primary cause in the lower purities and recoveries seen in this study. It is suggested that the monocytes phagocytose the magnetic nanobeads and become sufficiently magnetized to be retained within the Miltenyi column, reducing the purity of the positive eluent.

Antigens, CD34↗

PubMed2006

In situ labeling of immune cells with iron oxide particles: an approach to detect organ rejection by cellular MRI.

In vivo cell tracking by MRI can provide means to observe biological processes and monitor cell therapy directly. Immune cells, e.g., macrophages, play crucial roles in many pathophysiological processes, including organ rejection, inflammation, autoimmune diseases, cancer, atherosclerotic plaque formation, numerous neurological disorders, etc. The current gold standard for diagnosing and staging rejection after organ transplantation is biopsy, which is not only invasive, but also prone to sampling errors. Here, we report a noninvasive approach using MRI to detect graft rejection after solid organ transplantation. In addition, we present the feasibility of imaging individual macrophages in vivo by MRI in a rodent heterotopic working-heart transplantation model using a more sensitive contrast agent, the micrometer-sized paramagnetic iron oxide particle, as a methodology to detect acute cardiac rejection.

Animals↗