Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “elevational migration”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 721 records · Page 40Linked to original sources
PubMedDate not supplied

Blood low shear rate rheometry: influence of fibrinogen level and hematocrit on slip and migrational effects.

Red blood cell (RBC) aggregation is of prime importance in vivo and in vitro for low flow rates. It may be estimated by rheometrical measurements at low shear rates, but these are perturbed by slip and migrational effects which have already been highlighted in the past. These effects lead to a torque decay with time so that the true value of the stress at low shear rates may be greatly underestimated. Elevated aggregation being associated with different diseases, pathological blood samples show more pronounced perturbing effects and a strong time dependency in low shear rate rheometry. To test the dependence of slip and migrational effects on RBC aggregation, and particularly to determine the way in which they depend upon fibrinogen concentration ([Fb]), a home-made measuring system with roughened internal and external walls (170 microns roughness) was used to study low shear rate rheometry for RBC suspensions in PBS buffer containing albumin (at 50 g/l) and fibrinogen at various concentrations. The influences of hematocrit, shear rate, and fibrinogen concentration were investigated. Particular attention was paid to data acquisition at low shear rates (10(-3) s-1 to 3 x 10(-2) s-1). The combined influence of hematocrit and fibrinogen was investigated by adjusting hematocrit to 44 or 57% and fibrinogen concentration ([Fb]) to 3.0-4.5-6.5 g/l. Microscopic observations of the blood samples at rest were performed. They showed that different structures were formed according to fibrinogen concentration. The rheometrical measurements indicated that torque decay with shearing duration was strongly dependent on fibrinogen concentration and on shear rate at fixed hematocrit. Migrational and slip effects were more pronounced as shear rate decreased, fibrinogen concentration was raised, and hematocrit was lowered. The results have been explained on the basis of the expected microstructure of flowing blood in relation to the microscopic observations at rest.

Erythrocyte Aggregation↗
PubMed2006

Adrenomedullin increases the expression of calcitonin-like receptor and receptor activity modifying protein 2 mRNA in human microvascular endothelial cells.

Adrenomedullin (AM) is a multifunctional peptide hormone, which plays a significant role in vasodilation and angiogenesis, implicating it in hypertension as well as in carcinogenesis. AM exerts its effects via the calcitonin receptor-like receptor (CRLR, now known as CL) complexed with either receptor activity modifying protein (RAMP) 2 or 3. We have investigated the effect of AM on immortalized human microvascular endothelial cells 1, since endothelial cells are a major source as well as a target of AM actions in vivo. Cells treated with AM showed elevated cAMP in a time (5-45 min)-dependent and dose (10(-6)-10(-14) M)-dependent manner. Pre-treatment with the AM receptor antagonist AM(22-52) partially suppressed the AM-induced increase in cAMP levels. An increase in extracellular signal-regulated kinase 1/2 phosphorylation was observed after 5 min of treatment with 10(-8) M AM. This phosphorylation was specific, since we were able to block the AM-induced effect with 1 microM U0126, a specific mitogen-activated protein/extracellular signal-regulated kinase kinase inhibitor. Using real-time PCR, we were able to show for the first time that AM upregulates peptide and mRNA expression of vascular endothelial growth factor (VEGF). However, AM treatment of cells did not result in increased cell proliferation. Instead, we observed that AM and VEGF induced cell migration, which could be inhibited by the AM(22-52) and anti-VEGF antibody respectively. AM also significantly elevated mRNA levels of CL (after 2 and 24 h treatment) and RAMP2 (after 1 and 24 h treatment). The upregulation of the AM receptor at two time points reflects possibly different cellular responses to short- and long-term exposure to AM.

Adrenomedullin↗
PubMed2006

Exposure in fetus of methylazoxymethanol in the rat alters brain neurotrophins' levels and brain cells' proliferation.

Changes during gestation have been shown to induce brain maldevelopment associated with changes in neurotrophins as nerve growth factor (NGF), brain derived neurotrophic factor (BDNF) and neuropsychiatric disorders in humans. A rat model of altered prenatal brain development resembling the onset of schizophrenia has been obtained by administering in fetus methylazoxymethanol (MAM) at gestational day 12 which impairs the growth of limbic pathways between the entorhinal cortex and the hippocampus. Using the MAM model we studied in young rats the brain levels of both NGF/BDNF and their main receptors, TrkA/TrkB, to investigate whether or not changes in neurotrophins could affect the presence of brain BrdU positive cells. We found increased NGF and BDNF protein levels, associated with elevated TrkA and TrkB expression, in the hippocampus, entorhinal cortex, olfactory lobes and subventricular zone (SVZ), brain areas playing a key role in the production and migration of new dividing cells. We also found higher levels of BrdU positive cells in the SVZ and hippocampus but not a significant potentiation in the entorhinal cortex and olfactory lobes. All together the findings indicate that prenatal MAM exposure in young rats may elicit both neurotrophins' elevation and cell proliferation in limbic brain areas.

Analysis of Variance↗
PubMed2003

A role for alphabeta1 integrins in focal adhesion function and polarized cytoskeletal dynamics.

alphabeta1 integrins have been implicated in the survival, spreading, and migration of cells and tissues. To explore the underlying biology, we identified conditions where primary beta1 null keratinocytes adhere, proliferate, and display robust alphavbeta6 integrin-induced, peripheral focal contacts associated with elaborate stress fibers. Mechanistically, this appears to be due to reduced FAK and Src and elevated RhoA and Rock activities. Visualization on a genetic background of GFPactin shows that beta1 null keratinocytes spread, but do so aberrantly, and when induced to migrate from skin explants in vitro, the cells are not able to rapidly reorient their actin cytoskeleton toward the polarized movement. As judged by RFPzyxin/GFPactin videomicroscopy, the alphavbeta6-actin network does not undergo efficient turnover. Without the ability to remodel their integrin-actin network efficiently, alphabeta1-deficient keratinocytes cannot respond dynamically to their environment and polarize movements.

Actins↗
PubMed2005

Significance of macrophage inflammatory protein-1 alpha (MIP-1alpha) in multiple myeloma.

Macrophage inflammatory protein-1 alpha (MIP-1alpha) is a member of the CC chemokine family and is primarily associated with cell adhesion and migration. It is produced by myeloma (MM) cells and directly stimulates osteoclast formation and differentiation in a dose dependent way. MIP-1alpha protein levels were elevated in the bone marrow plasma of MM patients and correlated with disease stage and activity. MIP-1alpha was also elevated in the serum of myeloma patients with severe bone disease and correlated positively with bone resorption markers providing evidence for a causal role of MIP-1alpha in the development of lytic bone lesions in MM. MIP-1alpha has also been found to stimulate proliferation, migration and survival of plasma cells. Mice, which were inoculated with myeloma cells and treated with a monoclonal rat anti-mouse MIP-1alpha antibody, showed a reduction of both paraprotein and lytic lesions. In addition, MIP-1alpha enhanced adhesive interactions between myeloma and marrow stromal cells, increasing the expression of RANKL and IL-6, which further increased bone destruction and tumor burden. Myeloma patients with high MIP-1alpha serum levels have poor prognosis. The positive correlation between MIP-1alpha and beta(2)-microglobulin that has been observed in MM patients at diagnosis further supports the notion that MIP-1alpha is not only a chemokine with osteoclast activity function but is also implicated in myeloma growth and survival. Therefore, MIP-1alpha pathway may serve as a target for the development of novel anti-myeloma therapies.

Animals↗
PubMed1989

Late passage cells display an increase in contractile behavior.

During aging, alterations in the extracellular matrix and cytoskeleton have been noted. Aging affects both the structure and the biological activity of fibronectin as well as the cellular content and organization of f-actin. The purpose of this study was to examine the functional significance of such alterations. Assays for cell migration, cell spreading, collagen gel contraction, and f-actin organization were conducted using diploid cells strains of high and low population doubling level (PDL). First, an assessment of cell spreading behavior revealed that high PDL cells spread more than low PDL cells. Second, analyses performed with a modified phagokinetic track assay indicate that high PDL cells migrate (phagocytize) faster than low PDL cells. Lastly, it was found that high PDL cells contract collagen gels faster than low PDL cells. Therefore, high PDL cells are capable of exerting more force upon their extracellular matrix than low PDL cells. In agreement with previous observations, we found by phalloidin staining that the f-actin content of high PDL cells was substantially greater than that of low PDL cells. The elevated f-actin content of high PDL cells could promote increased cellular contractility thereby leading to the increase in cell spreading, migration, and collagen gel contraction observed here.

Actins↗
PubMed1975

Elevation of a serum component in periodontal disease capable of modulating chemotactic infiltration.

Serum from dental patients was examined for its capacity to affect migration of polymorphonuclear leukocytes toward a complement-independent chemotactic factor, bacterial filtrate of Escherichia coli, (BF). Seven subjects with advanced periodontitis, documented with clinical measurements of pocket depth, loss of attachment, indices for gingival inflammation and oral hygiene, were paired with normal subjects of similar age and sex. This study shows that patients whose only apparent clinical symptom was severe periodontal inflammation harbor a heat-stable, serum component which neutralizes factors chemotactic for polymorphonuclear leukocytes. A role for this component in modulation of inflammatory infiltration is discussed.

Chemotaxis↗
PubMed1997

Cross talk between adhesion molecules: control of N-cadherin activity by intracellular signals elicited by beta1 and beta3 integrins in migrating neural crest cells.

During embryonic development, cell migration and cell differentiation are associated with dynamic modulations both in time and space of the repertoire and function of adhesion receptors, but the nature of the mechanisms responsible for their coordinated occurrence remains to be elucidated. Thus, migrating neural crest cells adhere to fibronectin in an integrin-dependent manner while maintaining reduced N-cadherin-mediated intercellular contacts. In the present study we provide evidence that, in these cells, the control of N-cadherin may rely directly on the activity of integrins involved in the process of cell motion. Prevention of neural crest cell migration using RGD peptides or antibodies to fibronectin and to beta1 and beta3 integrins caused rapid N-cadherin-mediated cell clustering. Restoration of stable intercellular contacts resulted essentially from the recruitment of an intracellular pool of N-cadherin molecules that accumulated into adherens junctions in tight association with the cytoskeleton and not from the redistribution of a preexisting pool of surface N-cadherin molecules. In addition, agents that cause elevation of intracellular Ca2+ after entry across the plasma membrane were potent inhibitors of cell aggregation and reduced the N-cadherin- mediated junctions in the cells. Finally, elevated serine/ threonine phosphorylation of catenins associated with N-cadherin accompanied the restoration of intercellular contacts. These results indicate that, in migrating neural crest cells, beta1 and beta3 integrins are at the origin of a cascade of signaling events that involve transmembrane Ca2+ fluxes, followed by activation of phosphatases and kinases, and that ultimately control the surface distribution and activity of N-cadherin. Such a direct coupling between adhesion receptors by means of intracellular signals may be significant for the coordinated interplay between cell-cell and cell-substratum adhesion that occurs during embryonic development, in wound healing, and during tumor invasion and metastasis.

Animals↗
PubMed1997

Migration studies from paper and board food packaging materials. 1. Compositional analysis.

A survey of 32 paper and board materials intended for food contact has been undertaken. Sample composition was analysed to identify chemicals with a potential to migrate to foods. Representative materials covering a range of uses such as aqueous and fatty foods, and use at ambient and elevated temperatures, were obtained from industry. The samples were examined in their unfinished state, even where the final form would have included lamination to plastics, printing, or other treatments. A comprehensive and systematic analytical approach was applied which included determination of volatiles by headspace GC-MS, extraction using water, ethanol and chloroform with subsequent analysis by GC-MS and HPLC, and multi-element screening by ICP-MS. The solvent extracts were also weighed to determine the total amount of material available for migration. A large number of volatile substances were identified with alkyl and aryl aldehydes predominating in the majority of samples. Substances identified in solvent extracts included 2,6-di-tert-butyl-4-hydroxytoluene (BHT), di-tert-butylphenol, benzophenone, 4,4'-bis(dimethyl amino) benzophenone (Michler's ketone), triphenyl methane, bicyclohexylphenylphenanthrene carboxylic acid (and its methyl ester) and abietic acid. Levels of these substances were however generally below 1 mg/kg paper. Of the inorganic elements, arsenic and mercury were not detected above the limits of determination of 1.8 and 0.4 mg/kg respectively in any of the 10 samples examined. Cadmium was detected in teabag tissue and in unbleached Kraft paper at 0.3 mg/kg. Chromium was present in seven samples at 1.1-7.8 mg/kg, whilst lead was present in nine of the 10 samples at levels ranging from 0.3 to 5.9 mg/kg.

Benzophenones↗
PubMed2000

Acetabular revision with use of a bilobed component inserted without cement in patients who have acetabular bone-stock deficiency.

BACKGROUND: Massive deficiency of acetabular bone stock is a challenging problem in the increasing number of patients who need a revision of a failed hip arthroplasty. The bilobed cup has been presented as one alternative reconstruction technique for hips with extensive acetabular bone loss. The purpose of this study was to assess the results with use of a bilobed acetabular component inserted without cement for revision reconstruction in hips with acetabular bone deficiency in order to clarify the indications for its use and to identify the factors that influence the clinical and radiographic outcome. METHODS: Forty-one hips in thirty-eight patients had an acetabular revision with a bilobed acetabular component inserted without cement between December 1991 and December 1995. These hips were a subset of the 414 hips treated with an acetabular revision during the same period of time. One patient was lost to follow-up, and one died during the study period. Two patients who could not return for radiographic evaluation completed questionnaires. The remaining thirty-four patients (thirty-seven hips) were evaluated radiographically and clinically and were followed for an average of forty-one months (range, twenty-four to sixty-six months). RESULTS: Radiographic analysis demonstrated an improvement in the average vertical displacement of the hip center. At the time of the latest follow-up examination, 76 percent (twenty-eight) of the thirty-seven cups were stable, 8 percent (three) were probably unstable with a change in the screw position but no definite migration of the cup, and 16 percent (six) were unstable. Eight of the nine loose or probably loose components were in patients who had more than two centimeters of superior migration of the component and disruption of Kohler's line on preoperative radiographs. Additionally, implants were more likely to become unstable (demonstrating more than 4 degrees of change in the abduction angle or more than four millimeters of radiographic migration) when the inferior aspect of the component did not extend to or distal to the interteardrop line, which indicated that the component was undersized. CONCLUSIONS: On the basis of our early rate of probable or definite loosening of 24 percent (nine of thirty-seven cups) and the technical difficulties involved, we do not recommend the routine use of this component. We believe that this device is indicated when a patient has an oblong-shaped acetabular defect and the surgeon wants to correct an elevated hip center. However, the medial wall of the acetabulum (Kohler's line) should be intact if the failed component has migrated more than two centimeters. An alternative reconstruction technique, such as use of a structural allograft with or without an acetabular cage, is also an option in this situation.

Acetabulum↗
PubMed2004

IFN-gamma stimulates the expression of a novel secretoglobin that regulates chemotactic cell migration and invasion.

IFNs are a family of cytokines that alert the immune system against viral infections of host cells. The IFNs (IFN-alpha, IFN-beta, and IFN-gamma) interact with specific cellular receptors and stimulate the production of second messengers, leading to the expression of antiviral and immunomodulatory proteins. We report in this study that IFN-gamma stimulates the expression of a novel gene that encodes a protein with 30% amino acid sequence identity with uteroglobin, the founding member of the newly formed Secretoglobin (SCGB) superfamily. We named this protein IFN-gamma-inducible SCGB (IIS), because its expression in lymphoblast cells is augmented by IFN-gamma treatment. IIS is expressed in virtually all tissues, and the highest level of expression is detectable in lymph nodes, tonsil, cultured lymphoblasts, and the ovary. Interestingly, although the expression of IIS mRNA is not significantly different in resting lymphoid cells, it is markedly elevated in activated CD8(+) and CD19(+) cells. Furthermore, treatment of lymphoblast cells with IIS antisense phosphorothioate (S)-oligonucleotides prevents chemotactic migration and invasion. Taken together, these results raise the possibility that this novel SCGB has immunological functions.

Amino Acid Sequence↗
PubMed2025

TPX2 promotes papillary renal cell carcinoma progression by forming a ceRNA with LINC00894.

PURPOSE: Papillary renal cell carcinoma (pRCC), particularly type 2, is associated with a poor prognosis. This study aimed to identify molecular mechanisms underlying pRCC progression and explore potential therapeutic targets to improve patient outcomes. METHODS: TPX2 expression was analyzed in tumor samples from patients with type 2 pRCC. In vitro experiments were conducted to assess the effects of TPX2 and LINC00894 knockdown and overexpression on the proliferation and migration of Caki-2 and ACHN cells. Immunohistochemical analysis of tissue microarrays was performed to evaluate the associations between TPX2 expression and clinicopathological characteristics in type 2 pRCC patients. RESULTS: Elevated TPX2 expression was significantly associated with a worse prognosis in type 2 pRCC patients and served as an independent risk factor for overall survival. Knockdown of TPX2 in Caki-2 and ACHN cells significantly reduced cell proliferation and migration. Additionally, LINC00894 was highly expressed in type 2 pRCC and correlated with poor prognosis. Mechanistically, miR-660-5p targeted the TPX2 3' UTR, promoting TPX2 degradation, while LINC00894 competitively bound to miR-660-5p, protecting TPX2 from miRNA-mediated degradation and exerting a pro-oncogenic effect. Immunohistochemical analysis revealed significant correlations between TPX2 expression and clinicopathological features, including tumor thrombus volume, tumor diameter, pathological TNM stage, and Fuhrman grade. CONCLUSION: This study underscores the critical role of TPX2 in type 2 pRCC progression and highlights its potential as a prognostic biomarker and therapeutic target. The TPX2/LINC00894/miR-660-5p regulatory axis provides novel insights into the molecular mechanisms driving pRCC and offers a promising avenue for improving patient prognosis.

Humans↗
PubMed1991

Dynamic morphology of metastatic mouse T-lymphoma cells invading through monolayers of 10T1/2 cells.

We have used an in vitro model system to analyze cytomechanical aspects of tissue infiltration by T-lymphocytes. The interaction of metastatic T-lymphoma cells with a precultured monolayer of 10T1/2 fibroblast-like cells was recorded in time-lapse video with alternating phase contrast and reflection interference contrast microscopy. Sectioning of embedded specimens as well as cytoskeletal stainings have been performed on matching cocultures. The lymphoma cells did not strongly attach or spread on the dorsal surface of the monolayer cells. Invasion started with the protrusion of a pseudopodium through a narrow gap, and conspicuous constriction of the invading cell's body and nucleus was a consistent feature during the later steps. Overt retraction of the target cells was not seen, but the invading lymphoma cells elevated the fibroblasts over relatively large areas, thereby creating dome-shaped open spaces, allowing for further migration under the monolayer with minimal resistance. Invasion was not unidirectional but was readily reversible at any stage. Due to this wavering character, an invasion event could take more than 1 hour, although the shape alterations involved were fast. Even after the invasion process had been completed, the lymphoma cells could come out from below the monolayer again. Therefore we propose that invasion in this model should be considered as a dynamic equilibrium. Invading T-lymphoma cells displayed diffuse F-actin staining and a well-organized microtubular complex with the centrosomes behind the nucleus in the uropod, which also contained most vesicular organelles.

Actins↗
PubMed2000

Corticosterone and nocturnal torpor in the rufous hummingbird (Selasphorus rufus).

Three experiments were designed to investigate whether corticosterone (CORT), known to have a role in restoration of energy homeostasis, regulates nocturnal torpor, an energy conservation state used by some small mammals and birds to offset environmental challenges to energy balance. In two experiments, one during autumn migration and one during early spring molt, captive rufous hummingbirds (Selasphorus rufus) were fed control and dilute (85% strength) nectar on alternate days. In migratory birds, torpor occurred more frequently over all, and nectar dilution resulted in increased torpor duration and increased concentration of CORT in evening but not midday cloacal fluid (CF) samples. In molting birds, torpor occurred infrequently on both control and food dilution days, but, although there was a significant increase in evening CF CORT on food dilution days, torpor duration did not increase significantly in response and there was no correlation between torpor duration and CF CORT at either time of day. Daily CF CORT patterns showed an increase from midday to evening during migration, but the reverse pattern during the molt. In a third experiment, CORT administered in the nectar elevated the use of torpor and depressed food intake. The results of these three experiments support the hypothesis that CORT is involved in the regulation of torpor, but suggest that some feature of the CORT signal other than concentration per se may be required to fully explain seasonal changes in the relations among energy challenge, CORT, and nocturnal torpor in hummingbirds.

Animals↗
PubMed1981

Palate morphogenesis. VI. Identification of stellate cells in culture.

Mesenchymal cells from the palate of mouse embryos at day 14.5 of gestation produce a minor population of stellate cells in culture. These cells are often bipolar and spindle-shaped with long cytoplasmic processes similar to neural-crest cells. Culturing of explants of palatal mesenchyme enriched for this type of cell. Stellate cells were the first to migrate from explants, followed by fibroblast-like cells and then by squamous cells. The majority of the cells in the explant were fibroblast-like. Squamous cells were present mostly in the anterior and mid-palate and least frequently in those from the posterior palate. They may represent tooth-germ epithelium. When pieces of palate were dissected out and cultured for enrichment of non-muscle contractile systems, most of the migrating cells were stellate. These may represent the highly migratory cells that are, in part, responsible for elevation of the palate shelf. Serotonin was measured in cultured mesenchymal cells from the palate. Its occurrence is consistent with regulation of movement of palate cells.

Animals↗
PubMed1999

Immunomodulative effect of muramyldipeptide in mice with larval toxocarosis.

The phagocytic ability of polymorphonuclear leukocytes, the metabolic activity of peritoneal macrophages, the proliferative response of T- and B-cells, and the production of specific anti-Toxocara antibodies were studied in paratenic hosts with experimental larval toxocarosis after treatment with the immunomodulator muramyldipeptide for 119 days. Peroral infection of mice with 2,500 Toxocara canis eggs partially reduced the numbers of cells and inhibited the activity of all cellular immune-response parameters studied. During most of the experiment the greatest suppression was recorded for the peritoneal-macrophage metabolic activity. Parenteral administration of muramyldipeptide to mice at two doses prior to and after infection restored and significantly stimulated the parasite-inhibited phagocytic ability of blood polymorphonuclear leukocytes, metabolic activity of macrophages, and T-lymphocyte proliferative response. It also elevated the production of specific circulating anti-Toxocara antibodies. The immunomodulator significantly reduced the count of migrating T. canis larvae in the host organism (30.6%) and decreased by half the percentage of larvae in the brain.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1990

Atherogenesis, calcium and calcium antagonists.

Hypercholesterolemia and arterial hypertension are highly interrelated risk factors of atherosclerosis. Early lesions in nonhuman primates with dietary hypercholesterolemia resemble atherosclerotic lesions demonstrable in the arteries of American children with comparably elevated plasma cholesterol levels. Lesion formation depends upon calcium-regulated cellular processes such as chemotaxis, adhesion, migration, proliferation, lipid uptake and necrosis. Interventions acting on cell calcium uptake including treatment with calcium chelating agents, lanthanum trichloride, and calcium antagonists may retard atherogenesis in fat-fed animals in the absence of hypolipidemic effects. Recent controlled coronary angiographic trials in patients with coronary artery disease suggest that calcium antagonists may retard the progression of coronary atherosclerosis in humans. Large-scale long-term studies are needed to determine the utility of these agents for the treatment of coronary artery disease.

Animals↗
PubMed1989

SPARC: a Ca2+-binding extracellular protein associated with endothelial cell injury and proliferation.

SPARC (Secreted Protein that is Acidic and Rich in Cysteine) is a Ca2+-binding, stress-related protein released in vitro by both malignant and normal cells derived from all primordial germ layers. It is specifically elevated in endothelial cells as a result of "culture shock" (characterized by high levels of proliferation and migration) and exhibits density-dependent secretion. Exposure of bovine aortic endothelial cells to endotoxin results in a 70-100% increase in secreted protein, with a three-fold increase in SPARC. Immunofluorescence histochemistry on mouse tissues revealed (a) a preferential association of SPARC with highly proliferative cells (e.g., gut epithelia, mammary gland, and epidermis), (b) a cell surface or stromal location in thymus, lung, and salivary gland, (c) staining of epididymidal epithelium and testicular cells, and (d) an association with somites of 14 d mouse embryos. We envision SPARC as an extracellular modulator of Ca2+ and other cation-sensitive proteins/proteinases, that facilitates cellular proliferation in response to injury and to developmental signals.

Animals↗