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At least 253 records · Page 14Linked to original sources
PubMed2001

SDF-1-induced actin polymerization and migration in human hematopoietic progenitor cells.

OBJECTIVE: The capacity of hematopoietic progenitor cells (HPCs; CD34(+) cells) to respond to chemotactic stimulation is essential for their homing efficiency, e.g., during stem cell transplantation. Previous studies established that stromal cell-derived factor-1 (SDF-1) and its receptor CXCR-4 play an important role in the homing of HPCs. The aim of the present study was to analyze SDF-1-induced actin polymerization and migration of HL-60 cells and primary human CD34(+) cells. MATERIALS AND METHODS: SDF-1-induced migration of CD34(+) cells from cord blood (CB) and peripheral blood (PB) across fibronectin-coated filters was measured in a Transwell assay. Actin polymerization was detected using fluorescent phalloidin and analyzed by confocal microscopy and FACS analysis. RESULTS: SDF-1 induced a rapid and transient increase in actin polymerization and in polarization of the actin cytoskeleton in primary CD34(+) cells and HL-60 cells. SDF-1 was found to induce significantly more actin polymerization in CB CD34(+) cells that show fast migration in vitro compared to slow migrating PB CD34(+) cells. Moreover, CB CD34(+) cells that had migrated toward SDF-1 showed an elevated and prolonged rise in F-actin upon second exposure to SDF-1 compared to nonmigrated cells, although both cell types expressed equal levels of the SDF-1 receptor CXCR-4. CONCLUSIONS: The relatively high migratory capacity of CB-derived human HPCs is not related to cellular polarization or high expression of the SDF-1 receptor but is largely determined by their capacity to efficiently polymerize F-actin in response to SDF-1.

Actins↗
PubMed2004

Apparatus and initial results for pressurized planar electrochromatography.

Pressurized planar electrochromatography (PPEC) is a new planar chromatographic technique in which the mobile phase is driven by electroosmotic flow, while the sorbent layer is pressurized in a manner that allows heat to flow from the layer through an electrically insulating, thermally conducting, sheet of aluminum nitride ceramic. A prototype apparatus for performing PPEC is described. Separation by PPEC is faster than by conventional TLC, and an example is presented of a 24-fold enhancement in the speed of separation. PPEC was performed on both regular and high-performance C18 layers, and the latter yield substantially faster separation. The sorbent layer requires conditioning at elevated temperature before use, and solute migration velocity increases with this temperature. The flow rate increases in a linear manner with increasing voltage and diminishes in a nonlinear manner with increasing pressure. Both electrical current and Joule heating diminish with increasing pressure, and the diminution of flow at high pressure can be compensated by an increase in voltage. PPEC is more efficient than classical TLC. Theoretical plate heights diminish with increasing Rf and are in the range 29-21 and 55-27 microm for the high-performance and regular plates, respectively. PPEC retains the advantages of classical TLC but has the ability to separate a substantially higher number of samples simultaneously. An example is presented on the separation of nine samples in 1 min on a 2.5 cm x 10 cm sorbent layer.

Journal Article↗
PubMed2006

The metastasis-associated gene S100A4 is a novel target of beta-catenin/T-cell factor signaling in colon cancer.

BACKGROUND & AIMS: Activation of the Wnt/beta-catenin pathway is frequently observed in colorectal cancers. Our aim was to elucidate the impact of gain-of-function beta-catenin on the metastasis-associated gene S100A4 in human colon cancer cell lines and tumors. METHODS: We analyzed cell lines heterozygous for gain-of-function and wild-type beta-catenin, and variants homozygous for gain- or loss-of-function mutation in beta-catenin, for S100A4 expression, cell motility, and in vivo metastasis. beta-catenin-mediated S100A4 promoter activation was tested by reporter assays. For human colon carcinomas, S100A4 expression, beta-catenin genotype, and metachronous metastasis were correlated. RESULTS: We identified S100A4 as the most regulated gene by gain-of-function beta-catenin using a 10K microarray. Cell lines with gain-of-function beta-catenin expressed up to 60-fold elevated S100A4 levels, displayed strongly increased migration and invasion in vitro, and induced metastasis in mice. S100A4 small interfering RNA, beta-catenin small interfering RNA, or dominant negative T-cell factor (TCF) knocked down S100A4 and blocked biological effects. S100A4 complementary DNA transfection increased migration and invasion. We identified a TCF binding site within the S100A4 promoter and demonstrated the direct binding of heterodimeric beta-catenin/TCF complexes. Reporter assays confirmed the beta-catenin-induced S100A4 promoter activity. Furthermore, S100A4 mRNA expression was increased in primary colon cancers, which later developed distant metastases, compared to non-metastasizing tumors. Colon tumors heterozygous for gain-of-function beta-catenin showed concomitant nuclear beta-catenin localization, high S100A4 expression, and metastases. CONCLUSIONS: S100A4 is a direct beta-catenin/TCF target, induces migration and invasion in vitro and metastasis in vivo, and has value for prognosis of metastasis formation in colon cancer patients.

Cell Movement↗
PubMed2002

Endotoxin potentiates ozone-induced pulmonary chemokine and inflammatory responses.

Urban air consists of a combination of environmental pollutants. Recent studies have suggested that normally innocuous doses of a particular pollutant may be rendered more toxic to the lung if primed by earlier events. Pulmonary inflammation has been observed in humans and in many animal species after endotoxin and ozone exposures. The present study was designed to test the hypothesis that inhalation of low levels of endotoxin following ozone exposure will potentiate ozone-induced lung injury. We exposed 8-week-old C57BL/6J mice to 1 ppm ozone for 24 hours; inhalation of low-dose endotoxin (37.5 EU) for 10 minutes; or 1 ppm ozone immediately followed by endotoxin inhalation (37.5 EU). The mice were examined 4 or 24 hours post exposure. After 24 hours of recovery, significant increases were measured in bronchoalveolar lavage (BAL) fluid levels of protein and lavageable polymorphonuclear neutrophils (PMNs) after coexposure to ozone followed immediately by endotoxin inhalation as compared to exposures individually. Messages encoding macrophage inflammatory protein (MIP)-1beta, MIP-1alpha, MIP-2, monocyte chemoattractant protein (MCP)-1, interleukin (IL)-1alpha, IL-1beta, IL-1Ra, IL-6, and Macrophage Migration Inhibitory Factor (MIF) were significantly elevated 24 hours post ozone followed by endotoxin as compared to exposure to ozone or endotoxin individually. These results demonstrate that preexposure to ozone, which primarily attacks the epithelium, can cause sensitization to a secondary stimulus through a mechanism that culminates in a greater and prolonged onset of inflammatory cell recruitment, pulmonary edema, and increased expression of chemokine and cytokine messages.

Animals↗
PubMed1993

Inactivation of YME1, a member of the ftsH-SEC18-PAS1-CDC48 family of putative ATPase-encoding genes, causes increased escape of DNA from mitochondria in Saccharomyces cerevisiae.

The yeast nuclear gene YME1 was one of six genes recently identified in a screen for mutations that elevate the rate at which DNA escapes from mitochondria and migrates to the nucleus. yme1 mutations, including a deletion, cause four known recessive phenotypes: an elevation in the rate at which copies of TRP1 and ARS1, integrated into the mitochondrial genome, escape to the nucleus; a heat-sensitive respiratory-growth defect; a cold-sensitive growth defect on rich glucose medium; and synthetic lethality in rho- (cytoplasmic petite) cells. The cloned YME1 gene complements all of these phenotypes. The gene product, Yme1p, is immunologically detectable as an 82-kDa protein present in mitochondria. Yme1p is a member of a family of homologous putative ATPases, including Sec18p, Pas1p, Cdc48p, TBP-1, and the FtsH protein. Yme1p is most similar to the Escherichia coli FtsH protein, an essential protein involved in septum formation during cell division. This observation suggests the hypothesis that Yme1p may play a role in mitochondrial fusion and/or division.

ATP-Dependent Proteases↗
PubMed2006

Low-level laser therapy applied transcranially to rats after induction of stroke significantly reduces long-term neurological deficits.

BACKGROUND AND PURPOSE: Low-level laser therapy (LLLT) modulates various biological processes. In the present study, we assessed the hypothesis that LLLT after induction of stroke may have a beneficial effect on ischemic brain tissue. METHODS: Two sets of experiments were performed. Stroke was induced in rats by (1) permanent occlusion of the middle cerebral artery through a craniotomy or (2) insertion of a filament. After induction of stroke, a battery of neurological and functional tests (neurological score, adhesive removal) was performed. Four and 24 hours poststroke, a Ga-As diode laser was used transcranially to illuminate the hemisphere contralateral to the stroke at a power density of 7.5 mW/cm2. RESULTS: In both models of stroke, LLLT significantly reduced neurological deficits when applied 24 hours poststroke. Application of the laser at 4 hours poststroke did not affect the neurological outcome of the stroke-induced rats as compared with controls. There was no statistically significant difference in the stroke lesion area between control and laser-irradiated rats. The number of newly formed neuronal cells, assessed by double immunoreactivity to bromodeoxyuridine and tubulin isotype III as well as migrating cells (doublecortin immunoactivity), was significantly elevated in the subventricular zone of the hemisphere ipsilateral to the induction of stroke when treated by LLLT. CONCLUSIONS: Our data suggest that a noninvasive intervention of LLLT issued 24 hours after acute stroke may provide a significant functional benefit with an underlying mechanism possibly being induction of neurogenesis.

Animals↗
PubMed1997

Plasmin-mediated proteolysis of osteocalcin.

Plasmin cleaves osteocalcin at a site within its carboxyl end, thus creating an N-midterminal 1-43 and a short C-terminal 44-49 peptides. The products of the cleavage were identified by matrix assisted laser desorption ionization time of flight mass spectrophotometry and by reversed phase high performance liquid chromatography followed by N-terminal sequence determination. When separated by sodium dodecyl sulfide-polyacrylamide gel electrophoresis in the presence of reducing agents, large (LF; N-midterminal) and a small molecular weight (SF; C-terminal) fragments can be identified. The major cleavage site involves arg43-arg44 amino acid residues, and the resulting 44-49 C-terminal fragment appears as a slow migrating band on native gels (SFnat). Elevated levels of calcium ion inhibit the plasmin-mediated lysis of osteocalcin. Plasmin-mediated cleavage of osteocalcin occurs both in solution and when bound to hydroxyapatite. Both osteocalcin cleavage products detach from the hydroxyapatite substrate. Diisopropyl fluorophosphate-inhibited plasmin does not displace osteocalcin from the hydroxyapatite surface. Previously, the C-terminal pentapeptide has been shown to be chemotactic for bone cells while bone particles lacking osteocalcin were resistant to bone resorption. We therefore hypothesize that the plasmin-mediated digestion of free and hydroxyapatite-bound osteocalcin could play a role in the regulation of bone remodeling.

Amino Acid Sequence↗
PubMed1997

[Ceramic cups for hip endoprostheses. 3: On the problem of osseointegration of monolithic cups].

The combination of ceramic with ceramic offers the option of minimising wear and the need for revision in total hip replacement. At first, uncemented monolithic ceramic sockets were implanted. Some of these did not prove successful. The prerequisites for fixation of an implant by bony integration are discussed i.e. the structural and surface compatibility of an implant. The reasons for the high revision rate associated with monolithic ceramic sockets are discussed. Using monolithic ceramic sockets only contact osteogenesis can in principle be achieved, which does not suffice for good long-term fixation. In many cases, soft tissue can be found at the ceramic socket/bone interface, and the ceramic sockets may as a result migrate and penetrate, creating conditions that elevate the rate of wear to unacceptable levels.

Biomechanical Phenomena↗
PubMed1999

[Mechanism of atherosclerosis in diabetes: altered cytokine network in the vascular wall].

In the diabetic vascular complication, biochemical and mechanical injuries to endothelial cells are involved not only in the process of microangiopathy, but also in diabetic atherosclerosis (or arteriosclerosis) which is so-called macroangiopathy. In the presence of diabetes or persistent hyperglycemia, many cytokines including growth factors such as PDGF, HB-EGF, IL-1 beta and TNF alpha are upregulated in intimal cells of the arterial or aortic wall. These changes alter the cytokine network in the common mechanism of atherosclerosis, "Response-to-injury hypothesis", and further accelerate the formation of atherosclerotic lesion. In addition, diabetes causes abnormal responsibility to HB-EGF, PDGF and TGF-beta in medial smooth muscle cells leading to the elevated activity to their proliferation and migration into the intima. Thus, all cell types consisting arterial or aortic wall are involved in the process of diabetic atherosclerosis.

Arteries↗
PubMed2003

Stimulation of CD40 inhibits Fas- or chemotherapy-mediated apoptosis and increases cell motility in human gastric carcinoma cells.

The widespread expression of CD40, a member of the tumor necrosis factor (TNF) receptor (TNFR) superfamily, is likely to account for the central role of CD40 in the regulation of humoral immunity and host defense. Interestingly, the expression of the CD40 in various types of carcinoma cells was often observed and conveys signals regulating diverse cellular responses, ranging from proliferation to growth suppression. Thus, the biologic role of the CD40-CD40L interaction in solid tumors is still controversial. In this study, we investigated the expression and function of the CD40 in gastric carcinoma cells. In 3-4,5 dimethylthiozol-2-yl-2,5-diphenyl tetrazolium bromide (MTT) assay and Annexin V/propidium iodide staining, CD40 stimulation using a soluble form of CD40 ligand did not affect cell viability, but significantly inhibited Fas-mediated or chemotherapy-mediated apoptosis in three CD40-positive gastric cancer cell lines. Moreover, in migration assay, CD40 stimulation induced an elevation of cell motility in CD40-positive gastric carcinoma cells. Our results show that the CD40 expression on gastric carcinoma makes cells less vulnerable to apoptosis induced by Fas or chemotherapy. These results suggest that the CD40 expression on gastric carcinoma may be associated with cell survival and elevation of cell motility.

Antineoplastic Agents, Phytogenic↗
PubMed2004

[Effect of dachengqi granule on human gastrointestinal motility].

OBJECTIVE: To study the therapeutic effect and mechanism of Dachengqi granule (DCQG) on some digestive motility disturbed diseases. METHODS: Gastroduodenojejunal manometry, electrogastrography (EGG), RIA of motilin and orocecal transit time test were applied to directly observe the effect of DCQG on human gastrointestinal motility. RESULTS: DCQG could significantly improve the postoperational EGG disorder, elevate the amplitude and time of migrating motor complex (MMC) phase III, prevent gastrointestinal reversed peristalsis, increase the blood level of motilin, decrease the orocecal transit time, and promote the recovery of gastrointestinal motility. CONCLUSION: DCQG is an effective digestive kinetic agent, which could be medicated conveniently in treating digestive motility disturbed diseases.

Adult↗
PubMed1989

[A case of aseptic meningoencephalitis with recurrent abnormal behavior, status epilepticus and aphthous stomatitis, improved by acyclovir].

A case of aseptic meningoencephalitis with recurrent abnormal behavior, status epilepticus and aphthous stomatitis was described. A 39-year-old man, who had a history of low grade fever and abnormal behavior over 2 years without mucocutaneo-ocular symptoms, was admitted to Shinshu University Hospital because of status epilepticus. On admission, neurological examination revealed comatose state with neck stiffness, anisocoria (right greater than left), conjugate deviation to right and bilateral pyramidal tract signs. His cerebrospinal fluid examination revealed a total protein content of 206 mg/dl with 22 lymphocytes and 134 polymorphonuclear leukocytes/mm3. EEG recorded on the 3rd hospital day showed periodic sharp waves and polyspikes, occurring every 1 seconds, predominantly arise from the right hemisphere, which corresponds to periodic lateralized epileptiform discharges (PLEDs). Herpes simplex encephalitis was suspected and acyclovir was administered. Neck stiffness and cerebrospinal fluid findings were improved and PLEDs disappeared. But aphthous stomatitis appeared and meningoencephalitis was relapsed. Laboratory examination revealed erythrocyte sedimentation rate 40 mm/hr, positive C-reactive protein, elevated CH50 and sialic acid, enhanced migration of neutrophils and HLA-B 51. Neuro-Behçet's syndrome was strongly suspected with laboratory data but the clinical course was atypical. His clinical signs were markedly improved after administration of prednisolone. The present case suggests that neuro-Behçet's syndrome with only a part of major symptoms could be diagnosed as viral encephalitis and acyclovir may be effective for the treatment of neuro-Behçet's syndrome.

Acyclovir↗
PubMed1999

Altered actin cytoskeleton and inhibition of matrix metalloproteinase expression by vanadate and phenylarsine oxide, inhibitors of phosphotyrosine phosphatases: modulation of migration and invasion of human malignant glioma cells.

Cell-matrix interactions exert a profound influence on cell function and behavior. Our earlier observations suggested that disruption of the actin cytoskeleton results in the inhibition of phorbol ester-induced matrix metalloproteinase (MMP)-9 expression. In this study, to understand the role of protein tyrosine phosphatases in matrix metalloproteinase-9 expression, we treated glioblastoma cells with vanadate and phenylarsine oxide (PAO), which are inhibitors of protein tyrosine phosphatases. Vanadate and PAO inhibited expression of phorbol ester-induced MMP-9 as well as constitutive expression of matrix metalloproteinase-2 in a dose- and time-dependent fashion. An assay of the activity of phosphotyrosine phosphatase (PTPase) indicated that vanadate-treated cells had reduced PTPase activity compared with that of untreated controls. Vanadate and PAO also inhibited actin polymerization, cell spreading, migration, and invasion of glioma cells. Furthermore, elevated levels of protein tyrosine phosphorylation were observed in vanadate- and PAO-treated cells in both a concentration- and time-dependent fashion and were seen to have an inverse correlation with focal adhesion kinase protein expression. These results suggest that vanadate and PAO inhibited migration and invasion of glioma cells by their effect on the cytoskeleton and inhibition of MMP expression.

Actins↗
PubMed1981

Newborn factor VIII complex: elevated activities in term infants and alterations in electrophoretic mobility related to illness and activated coagulation.

The factor VIII coagulant activity (FVIII:C), factor VIII related antigen (FVIII:RAG), and factor VIII ristocetin cofactor activity (FVIII:RCF) was determined in the cord blood samples of 30 healthy term newborns. Sodium citrate anticoagulant, cold, and a proteolytic inhibitor were used in sample processing. All three factor VIII activities were elevated in infants compared to adults; additionally, FVIII:RAG was significantly higher in vaginally compared with caesarean section delivered infants. Crossed immunoelectrophoresis of the term infant plasma showed a consistently normal factor VIII mobility. An additional group of 22 sick premature and term infants had determinations of factor VIII antigen and crossed immunoelectrophoresis. The FVIII:RAG of sick infants was approximately twice that of the well term infants. Infants with severe lung disease, asphyxia, thrombosis and sepsis had normal electrophoretic mobility despite marked elevations in FVIII:RAG. Abnormal, symmetrical, more anodal migrations were seen only in a group of severely ill newborns with dissiminated intravascular coagulation (DIC) or signs of activated fibrinolysis. These results suggest that the elevated FVIII activities seen in well infants and most sick newborns are the result of increased release of a normal form of the FVIII molecule. Those elevations seen in sick newborns with DIC result from increased release and the production of an altered, faster moving FVIII molecule.

Adult↗
PubMed2006

Regulation of human vascular smooth muscle cell migration by beta-adrenergic receptors.

Migration and proliferation of vascular smooth muscle cells (VSMCs) are two events involved in atherosclerosis, restenosis after balloon angioplasty, and stenosis of grafted vessels. Platelet-derived growth factor (PDGF) found in stenotic vessels is known to induce migration of VSMCs. VSMCs express both alpha- and beta-adrenergic receptors on their surface, and blood vessels are innervated by the adrenergic nervous system and exposed to circulating epinephrine. We examined the role of these receptors on PDGF-induced migration of VSMCs. VSMCs were cultured from saphenous vein segments. Migration was stimulated by PDGF. Effect of pretreatment of VSMCs with the beta-agonist isoproterenol, the alpha-agonist phenylephrine, or forskolin on PDGF-induced migration was examined with a modified Boyden chamber. Cell migration was quantitated by spectrophotometry. Intracellular cyclic AMP was determined by radioimmunoassay. PDGF significantly induced VSMC migration. Isoproterenol (0.1 and 1.0 microM) inhibited PDGF-induced migration by 30 per cent and 50 per cent, respectively. Forskolin (10 microM) completely blocked PDGF-induced migration. The migration inhibition by isoproterenol or forskolin was associated with a significant elevation of intracellular cyclic AMP. In contrast, phenylephrine had no effect on PDGF-induced migration or on cyclic AMP. Activation of beta-adrenergic receptors and the consequent rise in intracellular cyclic AMP inhibits migration of VSMCs induced by PDGF. These results are consistent with the notion that adrenergic agonists with substantial beta-receptor affinity, such as isoproterenol, can inhibit smooth muscle cell migration.

Adrenergic beta-Agonists↗
PubMed2005

Prognostic and functional significance of thromboxane synthase gene overexpression in invasive bladder cancer.

Thromboxane synthase (TXAS) is one of the enzymes downstream from cyclooxygenase-2 and catalyzes the synthesis of thromboxane A(2) (TXA(2)). TXAS was among the genes we identified based on its overexpression in invasive bladder tumors. TXAS is overexpressed in common forms of bladder tumors: 69 of 97 (71.1%) transitional cell carcinoma (TCC), 38 of 53 (71.6%) squamous cell carcinoma, and 5 of 11 (45.5%) adenocarcinoma relative to nontumor tissue. Overall, 112 of 161 (69.5%) invasive tumors exhibited elevated expression. Significantly, patients with tumors having >4-fold levels of TXAS expression showed significant statistical evidence of lower overall survival expressed by the estimated hazard ratio of 2.74 with P = 0.009 in Cox's regression analysis. TXAS mRNA expression was found to be an independent prognostic marker for patients with bladder cancer. Treatment of bladder cancer cell lines (T24 and TCC-SUP) with TXAS inhibitors and TXA(2) (TP) receptor antagonists reduced cell growth, migration, and invasion, whereas TP agonists stimulated cell migration and invasion. The positive correlation between elevated TXAS expression and shorter patient survival supports a potential role for TXAS-regulated pathways in tumor invasion and metastases and suggests that modulation of the TXAS pathway may offer a novel therapeutic approach.

Adenocarcinoma↗
PubMed2003

Stable isotopes as indicators of altitudinal distributions and movements in an Ecuadorean hummingbird community.

Altitudinal migration and dispersal is an important component of the life history of several temperate and tropical birds but remains poorly understood due to the limited success of mark and recapture techniques. Stable isotopes of hydrogen (deltaD) in rainfall, and to a lesser extent, carbon (delta13C) in plants are known to change with altitude and hence may provide the basis of a technique for tracking the altitudinal movements in birds and other wildlife. We investigated the potential for this technique by measuring delta13C, deltaD, and delta15N values in tail feathers of eight species of hummingbirds ( Phaethornis malaris, P. syrmatophorus, P. guy, Adelomyia melanogenys, Coeligena torquata, C. lutetiae, Metallura baroni, M. williami) along an altitudinal gradient (300-3,290 m asl) in the Andes Mountains of Ecuador. Feather delta13C and deltaD values were correlated and each changed significantly with elevation above 400 m. In general, we found good agreement between feather deltaD values and those predicted from a generalized relationship of precipitation and surface water deltaD with altitude. Similarly, feather delta13C values showed an enrichment of approximately 1.5 per thousand per 1,000 m over the linear portion of the elevational response. Stable-nitrogen isotope values were variable, and so did not provide useful information on elevation in birds, apart from trophic effects. Overall there appears to be good potential for using the (deltaD, delta13C) stable isotope approach to track altitudinal movements and to elucidate previously unrecognized patterns of life history variation in both temperate and tropical species that migrate across elevational isotopic gradients.

Altitude↗