UMLS:C0432222 - FACTA Search

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Query: UMLS:C0432222 (SEM)
47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We assessed the expression of the adhesion molecules leukocyte function antigen-1 (LFA-1, CD11a), intercellular adhesion molecule-1 (ICAM-1, CD54), homing-associated cell adhesion molecule (H-CAM, CD44), and c-kit (stem cell factor receptor) on the CD34+ progenitor population from the leukapheresis products of 23 patients (LP CD34+). For blood stem cell collection granulocyte colony-stimulating factor (G-CSF) or interleukin-3/granulocyte-macrophage colony-stimulating factor (IL-3/GM-CSF) was administered after cytotoxic chemotherapy. Furthermore, bone marrow- and blood-derived CD34+ progenitor cells from 6 normal volunteers (BM and PB CD34+) were analyzed. LFA-1 expression was higher on PB CD34+ (88.2 +/- 2.5%, mean +/- SEM) than on BM CD34+ (75.3 +/- 4.3%). Following cytokine administration, LFA-1 was expressed on only 59.7 +/- 3.7% of LP CD34+ at a low fluorescence intensity, suggesting that down-regulation of LFA-1 may facilitate the egress of cells from the bone marrow and prolong their circulation. In contrast, ICAM-1 was weakly positive on CD34+ cells from all sources. CD44 was expressed on the vast majority of CD34+ cells (> 95%) in all samples studied. The highest proportion of CD34+ cells costaining for c-kit was found in normal bone marrow (32.2 +/- 3.3%). In normal peripheral blood and after cytokine mobilization, fewer of the CD34+ cells weakly expressed c-kit (< 15%). The low percentage and level of c-kit expression may indicate that the majority of cytokine-mobilized CD34+ cells are lineage-committed progenitor cells, as reflected by the coexpression pattern for CD38, HLA-DR, and CD33.
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PMID:Expression of adhesion molecules and c-kit on CD34+ hematopoietic progenitor cells: comparison of cytokine-mobilized blood stem cells with normal bone marrow and peripheral blood. 752 8

The effect of different expansion protocols on the expression levels of CD49dw/CD29 (VLA-4), CD11a/CD18 (LFA-1), CD31 (PECAM-1), CD44, and CD34 was determined after cord blood CD34+ cells were cultured for defined periods with the following: 1) A growth factor mix (GFmix) containing interleukin (IL)-1, IL-3, IL-6, kit ligand (KL), G-CSF, GM-CSF, and erythropoietin (Epo); 2) IL-3 + KL; and 3) HS-5 (a human stromal cell line supernatant) + KL. Before culturing, cord blood CD34+ cells (> 95% purity) were 94 +/- 5% CD31+, 98 +/- 1% CD44+, 66 +/- 29% VLA-4+, and 68 +/- 18% LFA-1+ (mean +/- SEM). Immunophenotyping and morphological examination of pre- and post-cultured cells indicated that GFmix preferentially supported erythroid development, while IL-3+KL and HS-5+KL preferentially supported myeloid development. Similar to what other investigators have reported, there was an absolute increase in CD34+ cell numbers as well as clonogenic precursors with ex vivo expansion. However, the majority of clonogenic precursors post-expansion expressed CD34 antigen at reduced levels. Examination of adhesion molecules indicated that a majority of cells cultured with GFmix expressed PECAM-1 and LFA-1 at undetectable levels, but PECAM-1 and LFA-1 levels remained essentially unchanged when cells were cultured with IL-3+KL and HS-5+KL. Overall VLA-4 expression levels slightly increased and CD44 expression levels were more heterogeneous with ex vivo expansion. Nevertheless, LFA-1, VLA-4, PECAM-1, and CD44 expression levels remained essentially unchanged on cultured progeny retaining a CD34 phenotype, independent of the culture system used. Together these results indicate that differential modulation of adhesion markers occur with different culture conditions, yet adhesion receptor expression levels on progeny cells retaining a CD34 phenotype are essentially maintained independent of the culture conditions. And although there is an absolute increase in CD34+ cells after ex vivo expansion, a majority of clonogenic precursors have reduced levels of CD34 antigen.
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PMID:Differential modulation of adhesion markers with ex vivo expansion of human umbilical CD34+ progenitor cells. 931 Jan 90

Lectins or agglutinins are proteins with affinity for specific sugar residues. Peanut agglutinin (PNA) and the lectin from the edible mushroom (Agaricus bisporus, ABL) both bind to the disaccharide galactosyl beta-1,3-N-acetyl galactosamine alpha-. This is expressed in keratinocytes as an O-linked chain on CD44, a polymorphic membrane glycoprotein. Many lectins are mitogens and PNA is a mitogen for colonic epithelial cells. However, ABL reversibly inhibits proliferation of colonic cancer cell lines without cytotoxicity and thus has therapeutic potential in situations such as psoriasis where proliferation is increased. We have therefore investigated the effect of ABL on the growth of normal human cultured keratinocytes and a human papilloma virus (HPV)-transformed cell line. In a 5-day dose-response study, keratinocyte growth was greatly reduced by 1.0 microg/mL ABL and completely inhibited by 3.0 microg/mL ABL (ANOVA, P < 0.0001). Exposure to 1.0 microg/mL ABL for only 8 h gave the same growth inhibition as did continued exposure for 3 days. No cytotoxic or morphological changes were observed. An HPV-immortalized cell line was relatively resistant to ABL: in a 5-day dose-response study, exposure to 30 microg/mL was required to inhibit cell growth completely. Topical application of ABL 0.01% or 0.1% to normal human skin caused no change in skin erythema, blood flow or thickness compared with vehicle or baseline (n = 6). ABL 0. 1% in white soft paraffin was compared with vehicle in 11 psoriatic patients, using comparative contralateral plaques. Twice daily application for 2 weeks showed no significant difference from vehicle-treated sites, although the skin thickness of plaques fell from 5.3 +/- 0.4 (n = 11, mean +/- SEM) to 4.1 +/- 0.3 mm. In view of the in vitro results further studies are warranted, particularly if means can be found to improve the epidermal penetration of the relatively large ABL molecule (60 kDa).
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PMID:The antiproliferative effect of lectin from the edible mushroom (Agaricus bisporus) on human keratinocytes: preliminary studies on its use in psoriasis. 1021 68

Human mesenchymal stem/progenitor cells (MSCs) have been identified in adult bone marrow, but little is known about their presence during fetal life. MSCs were isolated and characterized in first-trimester fetal blood, liver, and bone marrow. When 10(6) fetal blood nucleated cells (median gestational age, 10(+2) weeks [10 weeks, 2 days]) were cultured in 10% fetal bovine serum, the mean number (+/- SEM) of adherent fibroblastlike colonies was 8.2 +/- 0.6/10(6) nucleated cells (69.6 +/- 10/microL fetal blood). Frequency declined with advancing gestation. Fetal blood MSCs could be expanded for at least 20 passages with a mean cumulative population doubling of 50.3 +/- 4.5. In their undifferentiated state, fetal blood MSCs were CD29(+), CD44(+), SH2(+), SH3(+), and SH4(+); produced prolyl-4-hydroxylase, alpha-smooth muscle actin, fibronectin, laminin, and vimentin; and were CD45(-), CD34(-), CD14(-), CD68(-), vWF(-), and HLA-DR(-). Fetal blood MSCs cultured in adipogenic, osteogenic, or chondrogenic media differentiated, respectively, into adipocytes, osteocytes, and chondrocytes. Fetal blood MSCs supported the proliferation and differentiation of cord blood CD34(+) cells in long-term culture. MSCs were also detected in first-trimester fetal liver (11.3 +/- 2.0/10(6) nucleated cells) and bone marrow (12.6 +/- 3.6/10(6) nucleated cells). Their morphology, growth kinetics, and immunophenotype were comparable to those of fetal blood-derived MSCs and similarly differentiated along adipogenic, osteogenic, and chondrogenic lineages, even after sorting and expansion of a single mesenchymal cell. MSCs similar to those derived from adult bone marrow, fetal liver, and fetal bone marrow circulate in first-trimester human blood and may provide novel targets for in utero cellular and gene therapy.
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PMID:Identification of mesenchymal stem/progenitor cells in human first-trimester fetal blood, liver, and bone marrow. 1158 36

Melanoma cells exhibit a high level of intrinsic or acquired resistance to the cytotoxic agents often associated with the over-expression of drug transporters such as P-glycoprotein (P-gp). In this in vitro study, we investigated the possible relationship between P-gp and CD44, the cell adhesion molecule involved in metastasis and tumor progression of melanoma cells. CD44 expression appeared to be similar in the parental sensitive M14 WT cells and in their resistant counterparts M14 ADR cells. Double-labeling of cryosectioned cells showed that P-gp and CD44 were transported from the synthesis loci to the cell periphery by different vesicles and began to coalesce in proximity of the plasma membrane; thus, P-gp and CD44 seemed to reach together the cell surface. Moreover, P-gp and CD44 appeared to be associated with ERM proteins. The invasive activities of both M14 WT and M14 ADR cells were analyzed by the "transwell chamber invasion" assay. M14 WT cells revealed low capacity to traverse the filters, both in the absence (motility) and in the presence (invasion) of a Matrigel coating. In comparison, M14 ADR cells displayed significantly higher motility and invasion. SEM observations showed that sensitive cells employed lamellar cytoplasmic extrusions to pass through the filter pores whereas resistant cells elongated along the hole through globular processes. In conclusion, the results herein reported suggest that drug resistance in melanoma cells appears associated with a more aggressive behaviour. P-gp and CD44 might cooperate to confer this more invasive phenotype.
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PMID:Invasive properties of multidrug resistant human melanoma cells. 1610 Oct 31

CD44, a transmembrane adhesion molecule involved in binding and metabolism of hyaluronan, has additional functions in inflammatory and immune responses, contributing to the ingestion and clearance of particles and apoptotic cells. Our goal was to determine the specific role of CD44 in phagocytosis and whether it functions as a primary or accessory phagocytic receptor. Using hyaluronan-coated beads and erythrocytes coated with antiCD44 antibodies as the phagocytic prey, we determined that CD44 mediates efficient phagocytosis in primary murine peritoneal macrophages and in the murine macrophage cell line RAW 264.7. In RAW cells, the phagocytic index for anti-CD44-coated erythrocytes was 25 +/- 3 (mean +/- SEM) compared with less than 1 for erythrocytes coated with isotype-matched control antibodies. Uptake of anti-CD44-coated erythrocytes was abrogated by pretreatment with a blocking antibody to CD44 and was absent in primary cultures of CD44-deficient murine macrophages. Down-regulation of Fc receptors by aggregated IgG-induced internalization, which blocks uptake of IgG-coated particles, had no effect on CD44-mediated particle engulfment. Using a combination of immunoprecipitation, pharmacologic inhibition, and genetic deletion, we determined that CD44-mediated phagocytosis involves Syk, Rac1, and phosphatidylinositol 3-kinase and induced activation of the phagocyte oxidase. We conclude that CD44 is a competent phagocytic receptor that efficiently mediates internalization of large particles.
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PMID:CD44 is a phagocytic receptor. 1645 48

Crosslinked gels (hylans) containing long-chain (MW>1 x 10(6)Da) hyaluronan (HA), a connective tissue GAG, show exceptional biocompatibility for vascular implantation but poorly interact with vascular endothelial cells (ECs). Previous studies showed in situ fragmentation of HA by UV light to bioactivate hylan gels and elicit enhanced EC responses. Since fragmented HA can be pro-inflammatory, it is important to define an optimal size distribution of HA fragments on the hylan surface that will recruit and support normally functional ECs and limit ulterior responses. Related studies have shown that exogenous models of HA do not necessarily replicate cell responses to HA scaffolds. Since scaffolds cannot be created based on fragmented HA alone, we sought to determine size-specific responses of ECs to HA substrates of defined fragment sizes by creation of HA-tethered culture surfaces. HA (1000, 200, 20 kDa) and an oligomer mixture were tethered onto an aminosilane (APTMS)-treated glass surfaces using a carbodiimide reaction. MALDI-TOF showed the HA digests to contain HA 4-8mers with a 75+/-0.4% w/w of 4mers. Immuno-fluorescence, SEM, AFM and XPS analysis revealed homogeneous amine and HA surfaces. An amine s-SDTB assay and HA fluorophore-assisted carbohydrate electrophoresis (FACE) indicated surface densities of 9+/-3 amine groups/nm(2) and 0.57+/-0.44 microg/cm(2), respectively. HA/HA fragments/oligomers were stable over 21 days of incubation in serum-free culture media. EC proliferation on these surfaces resulted was limited, a possible effect of smooth surface topography, high anionicity, and in case of 4mers, non-interaction with primary HA cell-surface receptors (CD44). This work is significant in that it allows testing of cell responses to substrates composed of single-sized fragments of HA that cannot by themselves be cross-linked into a gel. Future work in our lab will use this model to assess the effects of other HA oligomer sizes on EC behavior.
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PMID:A surface-tethered model to assess size-specific effects of hyaluronan (HA) on endothelial cells. 1704 32

Optimizing seeding efficiency, reducing delayed culture periods and mimicking native tissue architecture are crucial requirements for the development of seeding procedures in tissue engineering. In vascular applications, the tubular geometry of the grafts further hampers the efficient delivery of cells onto the scaffold. To overcome these limitations, a novel technology based upon the use of magnetic fields is presented in this study: a radial magnetic force drives the cells immediately onto the luminal surface of a tubular scaffold and immobilizes the cells on the substrate's surface promoting cell attachment. Human smooth muscle cells (SMCs) labeled with CD44 magnetic Dynabeads were successively seeded onto the luminal surface of a tubular shaped collagen membrane. After 5 h, one additional layer of human umbilical vein endothelial cells (HUVECs) labeled with CD31 magnetic Dynabeads was seeded onto the luminal SMCs. The co-culture was incubated during 5 days prior to analysis. Cell viability and expression profiles were preserved during the entire seeding process. Histological examination of the constructs highlighted densely packed multilayers of SMCs covered by a monolayer of endothelial cells. SEM inspection confirmed a heterotypic multilayer assembly formed by multiple layers of elongated SMCs covered by a single layer of endothelial cells. Seeding kinetics of HUVECs and SMCs showed over 90% seeding efficiency after 20 and 40 min magnetic exposure respectively. Magnetically induced cell seeding provides a valuable tool for rapid seeding procedures of tubular scaffolds while complying with the histological architecture of tissue.
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PMID:Direct magnetic tubular cell seeding: a novel approach for vascular tissue engineering. 1710 86

We have previously shown that cells isolated from the outer ears of adult mice are a source of mesenchymal stem cells that can be induced to differentiate into adipo-, osteo-, and chondrocytes. In this study, we demonstrate that ear mesenchymal stem cells (EMSC) express stromal cell-associated markers (CD44, CD73) and stem cell marker Sca-1 and can be differentiated into spontaneously contracting muscle cells. Treatment of cells with epidermal growth factor (EGF) change their morphology from fibroblast shapes into stick-like structures that show repeated spontaneous contractions. Under conditions that promote myogenic differentiation, EMSC expressed mRNA for myoD and ventricular specific myosin light chain (MLC-2v) and protein for connexin 43, sarcomeric alpha-actinin, myocyte enhancer factor 2c (MEF2c), myosin heavy chain (MyHC), myogenin, and sarco-endoplasmic reticulum Ca(2+)ATPase (SERCA) 1. However, the cells were negative for Nkx2.5, GATA4, and ANP. Intracellular Ca(2+) transients in spontaneously beating EMSC, visualized by Fluo-3AM, showed a frequency of Ca(2+) oscillations ranging over 28-59/min (mean 41.17 +/- SEM 1.54). We also demonstrated that small pieces of ear tissues (ear punches) collected from live mice provide sufficient numbers of EMSC to isolate, culture and differentiate them into myocytes. Due to the ease of acquiring an expanding repertoire of differentiated EMSC cell types by a noninvasive surgical procedure, we conclude that the ear may prove to be a potential source of autologous cells for regenerative medicine, as supported by the fact that ears are one of the best sources of cells for somatic cell nuclear transfer (SCNT).
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PMID:Ear mesenchymal stem cells (EMSC) can differentiate into spontaneously contracting muscle cells. 1737 Mar 16

The fabrication of biodegradable 3-D scaffolds enriched with multipotent stem cells seems to be a promising strategy for the repair of irreversibly injured tissues. The fine mechanisms of the interaction of rat mesenchymal stem cells (rMSCs) with a hyaluronan-based scaffold, i.e. HYAFF(R)11, were investigated to evaluate the potential clinical application of this kind of engineered construct. rMSCs were seeded (2 x 10(6) cells cm(-2)) on the scaffold, cultured up to 21 days and analysed using appropriate techniques. Light (LM), scanning (SEM) and transmission (TEM) electron microscopy of untreated scaffold samples showed that scaffolds have a highly porous structure and are composed of 15-microm-thick microfibres having a rough surface. As detected by trypan blue stain, cell adhesion was high at day 1. rMSCs were viable up to 14 days as shown by CFDA assay and proliferated steadily on the scaffold as revealed by MTT assay. LM showed rMSCs in the innermost portions of the scaffold at day 3. SEM revealed a subconfluent cell monolayer covering 40 +/- 10% of the scaffold surface at day 21. TEM of early culture showed rMSCs wrapping individual fibres with regularly spaced focal contacts, whereas confocal microscopy showed polarized expression of CD44 hyaluronan receptor; TEM of 14-day cultures evidenced fibronexus formation. Immunohistochemistry of 21-day cultures showed that fibronectin was the main matrix protein secreted in the extracellular space; decorin and versican were seen in the cell cytoplasm only and type IV collagen was minimally expressed. The expression of CD90, a marker of mesenchymal stemness, was found unaffected at the end of cell culture. Our results show that HYAFF(R)11 scaffolds support the adhesion, migration and proliferation of rMSCs, as well as the synthesis and delivery of extracellular matrix components under static culture conditions without any chemical induction. The high retention rate and viability of the seeded cells as well as their fine modality of interaction with the substrate suggest that such scaffolds could be potentially useful when wide tissue defects are to be repaired as in the case of cartilage repair, wound healing and large vessel replacement.
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PMID:Mesenchymal stem cell interaction with a non-woven hyaluronan-based scaffold suitable for tissue repair. 1901 59

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