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PubMed2003

Hip revision with impacted morselized allografts: unrestricted weight-bearing and restricted weight-bearing have similar effect on migration. A radiostereometry analysis.

BACKGROUND: No consensus exists as to whether to let patients bear weight or not after revision of a loosened hip prosthesis using morselized and impacted allograft bone and cement. In the original description of the method, the patients were advised not to bear weight for 3 months postoperatively. Theoretically, bone graft remodeling is enhanced by mechanical load, but an increased migration of the prosthesis within the graft can also be anticipated. In addition, practicing restricted weight-bearing is cumbersome for the patients. METHODS: The present study was initiated to evaluate the migration, as measured by radiostereometry analysis (RSA), in patients mobilized with unrestricted weight-bearing after a hip revision using the X-change Revision Instruments System. This group was compared with a previous series with restricted weight-bearing for the initial 3 months postoperatively. Seven stems and 12 sockets were evaluated by RSA over 2 years. Only patients without intraoperative complications were mobilized with unrestricted weight-bearing. RESULTS: All 7 stems migrated in the distal direction (median 2.6 mm; range 0.8-16.5 mm) and in the posterior direction (median 2.3 mm; range 0.7-22.1 mm). Eleven of the 12 sockets migrated in the proximal direction (median 2.5 mm; range 0.2-8.1 mm). The migration rate decreased gradually in all directions, but 3 stems and 5 sockets still migrated between the 1.5- and 2-year follow-ups. There were no significant differences in migration in any direction for either the stems or the sockets compared to the group with restricted weight-bearing. CONCLUSION: No increased migration occurred in the group free to bear weight as compared to restricted weight-bearing. We shall continue to allow unrestricted weight-bearing in cases where the femoral bone feels competent to withstand the initial load. It simplifies the postoperative mobilization, and we speculate that it might increase the remodeling of the graft.

Arthroplasty, Replacement, Hip↗
PubMed1999

Migration of transformed renal epithelial cells is regulated by K+ channel modulation of actin cytoskeleton and cell volume.

Migration of transformed renal epithelial (MDCK-F) cells depends on the polarized activity of a Ca2+-sensitive K+ channel (IK channel; Pflügers Arch 432:R87-R93, 1996). This study was aimed at elucidating the functional link between the IK channel and the actin cytoskeleton which is required for cell locomotion. We monitored migration of MDCK-F cells with video microscopy, quantified filamentous actin with phalloidin binding, and measured the intracellular Ca2+ concentration ([Ca2+]i) with the fluorescent dye fura-2/AM. We compared the effects of IK channel activation or inhibition with those of hypotonic swelling or hypertonic shrinkage. IK channel inhibition with charybdotoxin (CTX) or cell swelling (omission of up to 50 mmol/l NaCl) as well as IK channel activation with 1-ethyl-2-benzimidazolinone (1-EBIO) or cell shrinkage (addition of up to 100 mmol/l mannitol) reduce the rate of migration dose-dependently by up to 80%, i.e., to the same extent as cytochalasin D. Inhibition of migration is accompanied either by actin depolymerization (CTX and cell swelling) or by actin polymerization (1-EBIO and cell shrinkage). Changes of migration and phalloidin binding induced by CTX and cell swelling or by 1-EBIO and cell shrinkage, respectively, are linearly correlated with each other. CTX and cell swelling elicit a rise of [Ca2+]i whereas 1-EBIO and cell shrinkage induce a slight decrease of [Ca2+]i in most MDCK-F cells. Taken together IK-channel-dependent perturbations of cell volume and anisotonicity elicit virtually identical effects on migration, actin filaments and [Ca2+]i. We therefore suggest that cell volume - possibly via [Ca2+]i - is the link between IK channel activity, actin filaments and migration. We propose a model for how temporal and local changes of cell volume can support the migration of MDCK-F cells.

Actins↗
PubMed2004

Directional migration in the Hindu castes: inferences from mitochondrial, autosomal and Y-chromosomal data.

Genetic, ethnographic, and historical evidence suggests that the Hindu castes have been highly endogamous for several thousand years and that, when movement between castes does occur, it typically consists of females joining castes of higher social status. However, little is known about migration rates in these populations or the extent to which migration occurs between caste groups of low, middle, and high social status. To investigate these aspects of migration, we analyzed the largest collection of genetic markers collected to date in Hindu caste populations. These data included 45 newly typed autosomal short tandem repeat polymorphisms (STRPs), 411 bp of mitochondrial DNA sequence, and 43 Y-chromosomal single-nucleotide polymorphisms that were assayed in more than 200 individuals of known caste status sampled in Andrah Pradesh, in South India. Application of recently developed likelihood-based analyses to this dataset enabled us to obtain genetically derived estimates of intercaste migration rates. STRPs indicated migration rates of 1-2% per generation between high-, middle-, and low-status caste groups. We also found support for the hypothesis that rates of gene flow differ between maternally and paternally inherited genes. Migration rates were substantially higher in maternally than in paternally inherited markers. In addition, while prevailing patterns of migration involved movement between castes of similar rank, paternally inherited markers in the low-status castes were most likely to move into high-status castes. Our findings support earlier evidence that the caste system has been a significant, long-term source of population structuring in South Indian Hindu populations, and that patterns of migration differ between males and females.

Adult↗
PubMed2005

Role of the beta1-integrin subunit in the adhesion, extravasation and migration of T24 human bladder carcinoma cells.

The abilities of tumor cells to extravasate from the blood vessel system and to migrate through the connective tissue are prerequisites in metastasis formation. Both processes are chiefly mediated by integrins, which mediate both cell-cell and cell-matrix interactions. We investigated the role of integrin subunits in the adhesion, extravasation and migration of the highly invasive human bladder carcinoma cell line T24. Here we show that inhibition of the beta(1)-integrin subunit using the specific beta(1)-integrin blocking antibody 4B4 significantly reduces the adhesion to HUVEC and transmigratory activity of T24 cells. The blockade of the beta(1)-integrin subunit also resulted in a significantly reduced locomotory activity of T24 cells. A detailed cell migration analysis on a single cell level revealed that blockade of the beta(1)-integrin subunit leads to an altered migration pattern of single cells but does not influence migration per se. Migration parameters such as time active, velocity and distance migrated were significantly reduced as compared to untreated control cells. Our observations strongly suggest a central role for the beta(1)-integrin subunit in forming the cell-cell and cell-matrix bonds necessary for adhesion, extravasation and migration.

Carcinoma↗
PubMed1989

Stimulation of lymphocyte migration by endotoxin, tumor necrosis factor, and interferon.

Since several studies have demonstrated that lipopolysaccharide (LPS), tumor necrosis factor (TNF), and interleukin-1 (IL-1) enhanced lymphocyte binding to endothelial cells in vitro, we examined the effects of these agents on lymphocyte migration in vivo. Small peritoneal exudate lymphocytes (sPEL), which perferentially migrate into inflammatory sites, were radiolabeled with 111In and injected iv into rats. The id injection of LPS was a strong stimulus for the migration of these cells into the skin. TNF alpha was also a good stimulator of lymphocyte migration, while TNF beta and IL-1 alpha were weak or nearly inactive. Kinetic analysis demonstrated that migration to TNF was rapid, with a peak at 6 hr, followed by a steady decline, while migration to LPS was sustained for 24 hr. TNF alpha, TNF beta, and IL-1 alpha, when combined with interferon-gamma (IFN-gamma) or IFN-alpha/beta produced striking synergistic increases in lymphocyte migration. Combinations of the TNFs and IL-1 had less than additive effects, as did combinations of the IFNs. Qualitatively similar migration responses were found when spleen T cells instead of sPEL were studied.

Animals↗
PubMed1995

The role of calcium ions in DEAE-dextran-induced stimulation of neutrophil migration.

The polycation DEAE-dextran caused a strong enhancement of non-directed migration of rabbit peritoneal neutrophils. The activating effect on migration was completely annulled in the presence of the polyanion poly-D-glutamic acid, indicating that the effect depended on the positive charge of the macromolecule. Chemotaxis activated by the chemotactic peptide fMLP was only slightly affected by the polycation. In contrast with fMLP-activation, stimulation of migration by DEAE-dextran was dependent on the presence of extracellular Ca2+. DEAE-dextran also stimulated migration of electroporated neutrophils. The stimulation was absent when calcium was not present; the increase of migration was strongest at Ca(2+)-concentrations between 100 nM and 1 microM Ca2+. This indicates that the requirement for extracellular Ca2+ in intact cells is a reflection of the intracellular requirement. Several types of calcium blockers gave a moderate inhibition of DEAE-dextran activated migration. Activation of migration by DEAE-dextran of electroporated neutrophils was completely inhibited by calcium channel blockers, at very low concentrations. The results suggest that both Ca(2+)-fluxes across the plasma membrane and Ca2+ from intracellular stores are required for DEAE-activated migration, and that the calcium from the intracellular source is required on a place where the extracellular Ca2+ has no, or limited, admittance.

Animals↗
PubMed1988

Neural crest migration in 3D extracellular matrix utilizes laminin, fibronectin, or collagen.

The trunk neural crest originates by transformation of dorsal neuroepithelial cells into mesenchymal cells that migrate into embryonic interstices. Fibronectin (FN) is thought to be essential for the process, although other extracellular matrix (ECM) molecules are potentially important. We have examined the ability of three dimensional (3D) ECM to promote crest formation in vitro. Neural tubes from stage 12 chick embryos were suspended within gelling solutions of either basement membrane (BM) components or rat tail collagen, and the extent of crest outgrowth was measured after 22 hr. Fetal calf serum inhibits outgrowth in both gels and was not used unless specified. Neither BM gel nor collagen gel contains fibronectin. Extensive crest migration occurs into the BM gel, whereas outgrowth is less in rat tail collagen. Addition of fibronectin or embryo extract (EE), which is rich in fibronectin, does not increase the extent of neural crest outgrowth in BM, which is already maximal, but does stimulate migration into collagen gel. Removal of FN from EE with gelatin-Sepharose does not remove the ability of EE to stimulate migration. Endogenous FN is localized by immunofluorescence to the basal surface of cultured neural tubes, but is not seen in the proximity of migrating neural crest cells. Addition of the FN cell-binding hexapeptide GRGDSP does not affect migration into either the BM gel or the collagen gel with EE, although it does block spreading on FN-coated plastic. Thus, although crest cells appear to use exogenous fibronectin to migrate on planar substrata in vitro, they can interact with 3D collagenous matrices in the absence of exogenous or endogenous fibronectin. In BM gels, the laminin cell-binding peptide, YIGSR, completely inhibits migration of crest away from the neural tube, suggesting that laminin is the migratory substratum. Indeed, laminin as well as collagen and fibronectin is present in the embryonic ECM. Thus, it is possible that ECM molecules in addition to or instead of fibronectin may serve as migratory substrata for neural crest in vivo.

Animals↗
PubMed1992

Quantitative analysis of autocrine-regulated, matrix-induced, and tumor cell-stimulated endothelial cell migration using a silicon template compartmentalization technique.

Autocrine-regulated, matrix-induced, and tumor cell-stimulated endothelial cell migration was quantitatively analyzed using a two-dimensional, two-compartment coculture system. Silicon templates were used to subdivide 35-mm tissue culture dishes into two separate compartments. Endothelial cells were grown to confluence in the inner compartment and released from growth arrest by removal of the silicon template. The distance of endothelial cell outgrowth from the monolayer was measured in 24-h intervals. Endothelial cells from different vascular beds migrated with different migration rates (large vessel endothelial cells greater than hemangioendothelioma cells greater than microvessel endothelial cells). Prior coating of tissue culture wells with fibronectin, type I collagen, or type IV collagen and increasing serum concentrations strongly enhanced endothelial cell migration. Seeding tumor cells into the outer compartment prior to removal of the silicon template permitted the direct coculture analysis of tumor cell-induced endothelial cell migration. Microvascular endothelial cell migration was stimulated in a tumor cell number-dependent fashion, whereas large vessel endothelial cells could not consistently be stimulated by coculture with tumor cells. It is concluded that silicon templates offer a useful approach for the quantitative study of migration of anchorage-dependent cells, permitting follow-up measurements over several days, the study of matrix effects, and the direct coculture analysis of cell migration.

Blood Proteins↗
PubMed1991

Enhancement of migration in bovine endothelial cells by eicosapentaenoic acid pretreatment.

It has been recognized that endothelial cell migration is an important process in the regeneration of injury in blood vessels. In this study, we examined the effects of polyunsaturated fatty acids on the migration of cultured endothelial cells using a modified Boyden chamber. When endothelial cells isolated from bovine carotid artery were pretreated for 2 days with 5 micrograms/ml of either arachidonic acid, eicosapentaenoic acid or docosahexaenoic acid, every polyunsaturated fatty acid was incorporated substantially into cellular phospholipids. The content of arachidonic acid increased from 9.27 to 23.9% by the arachidonic acid pretreatment, and that of eicosapentaenoic acid and docosahexaenoic acid increased from 9.57 to 11.85% by the eicosapentaenoic acid pretreatment and from 5.56 to 18.40% by the docosahexaenoic acid pretreatment, respectively. Pretreatment of the cells with 0.5-5.0 micrograms/ml of eicosapentaenoic acid resulted in a dose-dependent increase in endothelial migration in response to fetal bovine serum. In contrast, pretreatment of the cells with arachidonic acid and docosahexaenoic acid had no effects on the cell migration. If eicosapentaenoic acid, however, was added directly to the migration assay system instead of the pretreatment, it did not show a profile of chemotactic factor. The eicosapentaenoic acid pretreatment also potentiated cell migration activity in response to several other chemotactic factors such as basic fibroblast growth factor, tumor necrosis factor-alpha and leukotriene C4. The effect of eicosapentaenoic acid on porcine smooth muscle cell migration was also examined. Although eicosapentaenoic acid was similarly incorporated into cellular phospholipids of smooth muscle cells by the pretreatment for 2 days, no stimulative effect was observed in the migration of smooth muscle cells at any doses (0.5-5.0 microns/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Simultaneous determination of the migration coefficient of each base in heterogeneous oligo-DNA by gel filled capillary electrophoresis.

The direct determination of migration coefficients was achieved by analysing the migration time of heterogeneous oligo-DNA with a gel filled capillary using the Gauss least-squares method for the observation functions, assuming that the migration time of oligo-DNA is dependent on its base composition and chain length. By using the coefficients obtained, the migration time of oligo-DNA of any known sequence that does not have a secondary structure can be estimated with an accuracy of less than 0.5-mer of cytidine. In addition, from the deviation of the actual migration time from the calculated migration time in certain specially designed base sequences, the existence of a secondary structure such as a hairpin structure was strongly suggested even in the presence of 7 M urea. From the investigation of the effects of secondary structure on migration time, it was concluded that this approach will give qualitative information on secondary structure, which may be applicable in work such as single strand conformational polymorphism (SSCP) analysis or antisense DNA analysis, in which secondary structure plays an important role in accelerating or decelerating migration times. The results of the analysis also predict the apparent chain length reversal from short to long together with a reduction in the actual chain length in DNA sequencing using capillary electrophoresis.

Base Composition↗
PubMed1983

Quantitation of polymorphonuclear leukocyte migration under agarose by enzyme assay.

Migration of polymorphonuclear leukocytes under agarose is widely used to assay the mobility of these cells. We modified this assay so that directed and random migration of polymorphonuclear leukocytes might be quantitated rapidly and objectively by an enzyme method. The optimal method used gelatin-agarose (0.25% gelatin; 0.875% agarose) gel layered on glass coverslips. At the end of the migration period, the leukocytes which had not migrated under the agarose were removed by aspiration and washing. The remaining leukocytes were solubilized with Triton X-100 and the myeloperoxidase activity on the coverslips determined. With appropriate standards, this activity could be used to estimate the number of polymorphonuclear leukocytes which had migrated in a random or in a directed (chemotactic) manner. Excellent correlation was observed between the myeloperoxidase method and direct microscopic counting of the number of cells that had migrated. The sensitivity of the assay could be enhanced by inducing bidirectional migration under 2 simultaneous gradients of chemotactic factor situated 180 degrees apart. This assay is objective, reproducible and combines the simplicity of assessing migration by measuring distance of the 'leading cell front' with the accuracy of individual cell counting.

Cell Movement↗
PubMed1991

Identification and quantification of human peripheral blood lymphocytes and monocytes following migration into nitrocellulose filters.

Previously, in order to evaluate the migration of specific types of lymphocytes (e.g., T or B cells, CD4 or CD8 subsets) using the Boyden chamber technique, the relevant cell populations have first been purified. We report here a method which permits identification of the lymphocytes following migration into the nitrocellulose filters. After fixation, the filters are exposed to specific anti-lymphocyte monoclonal antibodies and the reaction is visualized via a second gold-linked antibody. Monocyte-depleted lymphocytes isolated from human peripheral blood are routinely used for migration but mixed mononuclear cell preparations can also be used. This was shown by comparing lymphocyte migration in monocyte-containing and monocyte-depleted cell suspensions isolated from the same donor. The presence of monocytes did not influence the migration of normal resting T lymphocytes. With human peripheral blood as starting material the method is most suitable for the evaluation of T cell migration since, in most instances, T cells are the predominant lymphocyte population. When the B cell count is normal (5-10% total lymphocytes), quantification of B cell migration requires enrichment but not complete purification of this population. Migrating monocytes can also be identified. However, the antibody staining is less intense on the spread monocytes and, therefore, quantification must be performed by eye rather than with the Optomax image analyser.

Cell Movement↗
PubMed1994

An assay for the analysis of lymphocyte migration across cerebral endothelium in vitro.

We describe a recently developed assay for the analysis of leukocyte migration across cerebral endothelium in vitro. The endothelium is grown as monolayers on Goretex or Cyclopore membranes coated with extracellular matrix proteins and supported on inserts. This system permits the recovery and phenotyping of cells which migrate down through the endothelium. Using labelled lymphocytes we were able to differentiate four populations of cells, with differing degrees of mobility in the migration assay. We have compared the results from this system with those from conventional adhesion assays. Binding of cells to the endothelium is rapid, but is confined to a particular subpopulation of the applied lymphocytes. We have followed cell migration over 24 h in the system using normal and cytokine-activated endothelium and have found that whereas adhesion depends both on the state of lymphocyte activation and on the condition of the endothelium, the level of migration of stimulated lymphocytes is largely independent of endothelial activation. Moreover, whereas CD8+ cells bind well to the endothelium, it is the CD4+ cells which migrate most effectively. Comparison of brain and epididymal fat endothelium showed similar migration levels over 2 h, but migration was greater across epididymal fat endothelium at 24 h.

Adipose Tissue↗
PubMed1995

Uterine artery Doppler velocimetry in relation to trophoblast migration into the myometrium of the placental bed.

OBJECTIVE: To test the hypothesis that an abnormally high resistance in the uterine artery indicates impaired trophoblast migration into the myometrium of the placental bed. METHODS: Doppler velocimetry in the uterine artery was carried out in 43 pregnant women within 7 days before cesarean delivery and placental bed biopsy. A pathologist evaluated the placental bed biopsies histologically. Trophoblast migration was absent in 28 cases (impaired migration group) and present in 15 (migration group). Clinical characteristics were compared between these two groups. RESULTS: There was no significant difference in the mean gestational ages at delivery in the two groups, but those with impaired migration included a higher incidence of small for gestational age infants (46.4 versus 6.7%, P < .01) and a lower mean (+/- standard deviation) birth weight (1622 +/- 528 versus 2287 +/- 748 g, P < .01). The systolic-diastolic ratio (S/D) in the uterine artery was higher in the impaired migration group (2.45 +/- 0.81 versus 1.92 +/- 0.34, P < .05). The absence of migration could be deduced from the S/D of the uterine artery, with a predictive value of 92.3% when we set the cutoff value of the ratio at 2.5. CONCLUSION: The results suggest that abnormal uterine artery flow velocity waveforms may indicate impaired trophoblast migration into the myometrium of the placental bed.

Arteries↗
PubMed1996

Migration of cultured vascular smooth muscle cells into non-crosslinked fibrin gels.

We evaluated the migration of vascular smooth muscle cells into fibrin gels, using an in vitro assay system. Vascular smooth muscle cells from bovine fetal aorta migrated into fibrin gels and showed a characteristic elongated spindle-shaped appearance with long cytoplasmic processes. Varying the concentration of thrombin (0.05-1 NIHU/ml) used to form the fibrin gel had little effect on cell migration although higher concentrations of thrombin inhibited the migration. Migration of the cells into fibrin gels was dependent on RNA and protein synthesis but not on DNA synthesis. The addition of antithrombin III, hirudin, and D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone after gel formation had no effect, suggesting that residual thrombin in fibrin gels had no influence on subsequent cell migration. Neither the factor XIII-induced crosslinking of fibrin nor the fibrinopeptides released during gel formation were involved in the present migration assay system. Tranexamic acid, an inhibitor of plasminogen activator, or aprotinin, a plasmin inhibitor, also had no significant effect, suggesting that fibrinolysis induced by plasmin was not involved in this system. These findings showed that fibrin gels themselves induce the migration of vascular smooth muscle cells (haptotaxis) without other chemotactic or chemokinetic substances, suggesting an important role for fibrin in the development and progression of such vascular diseases as atherosclerosis, thrombosis and the development of restenosis following balloon angioplasty.

Animals↗
PubMed1993

The 'vapour-phase' migration of styrene from general purpose polystyrene and high impact polystyrene into cooking oil.

General purpose and high impact polystyrene (GPPS and HIPS, respectively) are used in many food packaging applications. In some packaging configurations, where there is no direct contact of a liquid surface with the polymer, 'vapour-phase' migration of styrene monomer from the polymer with subsequent absorption into food is thought to be a significant mode of transfer. Correlation of residual styrene concentrations in polystyrene with vapour-phase styrene migration is of interest in order to predict potential consumer exposure to styrene from food-packaging applications of this configuration. Studies of the migration of styrene from GPPS and HIPS into air with subsequent absorption of the monomer into cooking oil, 'vapour-phase' migration, was determined in a sealed system. The results showed that for both polymers the amount of styrene migrating from the polystyrene and being absorbed by the oil was proportional to the square root of the time of exposure. The diffusion coefficients calculated for the vapour-phase migration of styrene from both polymers were found to be in good agreement with the diffusion coefficients previously determined for the 'liquid-phase' migration of styrene from similar polymers where the polymers were completely submerged in the cooking oil. These results indicate that the styrene concentrations measured in both experiments were attributable to the intrinsic diffusion of styrene from polystyrene, and that contact with cooking oil did not accelerate migration in previous experiments.

Diffusion↗
PubMed1991

Human leucocyte migration through collagen matrices containing other extracellular matrix components.

The purpose of this study was to investigate the migration of human peripheral blood leucocytes through collagen gels containing extracellular matrix components in vitro. This further extends the findings of a previous study (Reid et al, 1990), using rabbit peritoneal neutrophils, in which it was found that increasing the mechanical strength of the gels decreased the cell migration. In the current study it was found that human neutrophil and lymphocyte migration through collagen matrices was inhibited by increasing the collagen concentration, whereas the presence of serum had no effect on migration. Incorporation of chondroitin sulphate into collagen gel matrices resulted in a slight increase in leucocyte migration. The presence of elastin had no effect on the migration of leucocytes through collagen matrices, whereas incorporation of hyaluronate into collagen matrices decreased leucocyte migration. The morphology of these matrices suggests that altered migration was not due to differences in pore size between fibres.

Cell Movement↗
PubMed1993

Transplantation of cultured type 1 astrocyte cell suspensions into young, adult and aged rat cortex: cell migration and survival.

The present study examined the fate and migration of transplanted astrocytes in different host ages. Additionally, the effect of donor cell age was examined in relation to cell migration. Cultured astrocytes from 5, 12 and 30 days in vitro were transplanted into young (postnatal day 5 and 21), adult (4.5 month), and aged (21 month) animals. The transplanted cells were labeled with Fast Blue, Fluorogold or DiI. The results confirmed previous studies demonstrating that transplanted cells were able to migrate successfully through host central nervous system and extended those findings to show that the age of the host significantly influenced donor cell migration distance. Migration was most extensive in young animals, as conditions supporting cell migration appeared to be lacking in older animals. Donor cells preferentially migrated on myelinated fiber tracts, rather than on unmyelinated fiber tracts or gray matter. The donor cells were not glial fibrillary acidic protein positive, indicating that either the cultured type 1 astrocytes did not survive transplantation or underwent significant remodeling of the intermediate filament network. It is also possible that a subpopulation of cells, possibly immature astrocytes which are present in the transplanted cell suspensions, flourished and subsequently migrated in the host brains.

Aging↗