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PubMed1999

Cytokine-induced sequential migration of neutrophils through endothelium and epithelium.

OBJECTIVE AND DESIGN: To better understand the mechanisms by which cytokines induced neutrophils to migrate into the airways, we constructed a novel in vitro model system. MATERIALS: Human umbilical vein endothelial cell (HUVE) monolayers were grown on top of permeable filters and human lung type II-like alveolar epithelial cell (A549) monolayers were grown on the undersurface of the filters. METHODS: The sequential migration of human neutrophils through the endothelium (apical to basal movement) and subsequently through the epithelium (basal to apical movement) in response to IL-1 beta or TNF alpha located basally to the epithelium was measured. RESULTS: We found that IL-1 beta and TNF alpha induced dose-responsive and time-dependent migration through the double monolayers-filter complex. The pattern of migration was similar, and the amount greater than or equal to that observed through either single monolayer/filter complex. Neutrophil migration through naked filters was generally less than that observed through the cellular barriers. The contribution of the monolayer orientation was also examined and found to favor the more physiologic directional migration of neutrophils through an endothelial and epithelial barrier, apical to basal and basal to apical, respectively. In contrast, FMLP-induced neutrophil migration was not dependent upon either the orientation or presence of the monolayer(s). CONCLUSIONS: Thus, we have established an in vitro model system to examine cytokine-induced sequential migration of neutrophils through endothelium and the respiratory epithelium in a manner analogous to that occurring with an in vivo airway stimulus causing neutrophil-rich airway inflammatory responses.

Cells, Cultured↗
PubMed2006

Uncemented HA-coated implant is the optimum fixation for TKA in the young patient.

UNLABELLED: Fixation of the tibial component in total knee arthroplasty in younger patients remains controversial. We evaluate the results of three different types of fixation of the Profix total knee arthroplasty in a randomized controlled trial of 97 consecutive knees (85 patients) with osteoarthrosis or inflammatory arthritis with 2-year followup of all patients. We randomized patients to three different types of fixation of the tibial component: cemented, uncemented (HA coated) with screws, or uncemented (HA coated) without screws. We performed clinical evaluations and radiostereometric analysis at 6 weeks, and 3, 6, 12 and 24 months postoperatively. The knees in the uncemented groups migrated more than those in the cemented group during the first 3 months, but at 2 years we observed no differences. The uncemented implants displayed all migration within the first 3 months. The cemented implants did not stabilize but had continuously increasing migration during the followup. Cementless implants without screws did not migrate more than implants with screws and displayed similar pattern of migration, indicating screws do not improve fixation. Uncemented fixation using hydroxyapatite-coated implants without screws seems to be the best solution for the younger patient. LEVEL OF EVIDENCE: Therapeutic Level I. See the Guidelines for Authors for a complete description of levels of evidence.

Adult↗
PubMed1985

Influenza virus-specific T cells fail to reduce lung virus titres in cyclosporin-treated, infected mice.

Cyclosporin A (CsA) inhibited the function(s) of transferred influenza-specific K,D-restricted cytotoxic T cells, which led to clearance of virus in the lungs of influenza virus-infected mice. CsA had no effect on the migration of the transferred cells to the lungs. The pattern of migration and the number of cells recovered from the lungs were similar when cells were transferred into normal, untreated, infected or CsA-treated, infected mice. CsA had no effect on the in vitro expression of cytotoxic activity by the K,D-restricted cytotoxic T cells. These findings strongly suggest that the in vivo clearance of influenza virus by K,D-restricted cytotoxic T cells involves a lymphokine mechanism.

Animals↗
PubMed1997

Aging, acculturation, salt intake, and hypertension in the Kuna of Panama.

The indigenous Kuna who live on islands in the Panamanian Caribbean were among the first communities described with little age-related rise in blood pressure or hypertension. Our goals in this study were to ascertain whether isolated island-dwelling Kuna continue to show this pattern, whether migration to Panama City and its environs changed the patterns, and whether the island-dwelling Kuna have maintained their normal blood pressure levels despite partial acculturation, reflected in an increased salt intake. We enrolled 316 Kuna participants who ranged in age from 18 to 82 years. In 50, homogeneity was confirmed by documentation of an O+ blood group. In 92 island dwellers, diastolic hypertension was not identified and blood pressure levels were as low in volunteers over 60 years of age as in those between 20 and 30 years of age. In Panama City, conversely, hypertension prevalence was 10.7% and exceeded 45% in those over 60 years of age (P < .01), blood pressure levels were higher in the elderly, and there was a statistically significant positive relationship between age and blood pressure (P < .01). In Kuna Nega, a Panama City suburb designed to maintain a traditional Kuna lifestyle but with access to the city, all findings were intermediate. Sodium intake and excretion assessed in 50 island-dwelling Kuna averaged 135 +/- 15 mEq/g creatinine per 24 hours, exceeding substantially other communities free of hypertension and an age-related rise in blood pressure. Despite partial acculturation, the island-dwelling Kuna Indians are protected from hypertension and thus provide an attractive population for examining alternative mechanisms.

Acculturation↗
PubMedDate not supplied

The sequential migration of neutrophils through endothelium and epithelium: a new model system.

To better understand the mechanisms by which neutrophils migrate into the airways, we constructed a novel in vitro model system with human umbilical vein endothelial cell (HUVE) monolayers grown on top of permeable filters and human lung Type II-like alveolar epithelial cell (A549) monolayers grown on the undersurface of the filters. The sequential migration of human neutrophils through the endothelium (apical to basal movement) and subsequently through the epithelium (basal to apical movement) in response to a stimulus located basally to the epithelium was measured. We found that the neutrophil chemoattractants, formylmethionylleucylphenylalanine (FMLP), leukotriene B4 (LTB4), and interleukin-8 (IL-8), induced dose-responsive migration through the double monolayer-filter complex. The pattern of migration was similar to that observed through either a naked filter or single monolayer-filter complex. Maximal chemotaxis through the double monolayer-filter complex was observed by 3 hours. Thus, we have established an in vitro model system to examine the sequential migration of neutrophils through endothelium and the respiratory epithelium in a manner analogous to that occurring with an in vivo airway stimulus causing neutrophil-rich airway inflammatory responses.

Cell Line↗
PubMedDate not supplied

[Is migration really a survival strategy? The case of northern Oaxacan Mixteca].

"Since the 1950s more than 15 million Mexicans predominantly from the southern states of Guerrero and Oaxaca have...migrated to the United States. The article describes the patterns of migration in a Mixteco community of Oaxaca, where 90% of the men and a growing number of women migrate once a year to the United States for illegal seasonal work. The analysis of the causes and effects of migration focuses on the non-economic aspects of this phenomenon and emphasizes the ideological and social motives for migrating, especially those related to ethnic identity and to the establishment of indigenous communities in the Mexican Nation-State." (SUMMARY IN ENG)

Americas↗
PubMed1998

Migration decisions among settler families in the Ecuadorian Amazon: the second generation.

The authors use survey data collected in 1990 from 418 household heads of recent settlements in the Ecuadorian Amazon to study the extent of and reasons for out-migration of the settlers' children. "Our research identifies the types and incidence of out-migration of young adults from settler households in the Ecuadorian Amazon, as well as the effects of individual and household-level factors of out-migration. Important gender differences in both the levels and patterns of migration and in the factors affecting migration decisions are documented."

Adolescent↗
PubMed1979

The development of the hippocampus and dentate gyrus in normal and reeler mice.

The histogenesis, the time of origin and the pattern of migration of the cells in the hippocampus and dentate gyrus, have been studied in normal and reeler mice. The earliest indication of a defect in the reeler hippocampus is seen on the fifteenth embryonic day (E15) which is at least 24 hours after the first indication of a defect in the neocortex. It is not until E18, that the dentate gyrus shows signs of its incipient abnormality. It appears then, that in both the hippocampus and the dentate gyrus the gene defect first manifests itself at the stage at which the definitive cellular layers are assembled. Experiments involving the injection of 3H-thymidine (3H-TdR) at different developmental stages have confirmed that the site and rate of cellular proliferation in the reeler hippocampus and dentate gyrus are normal, as is the initial pattern of cell migration. However, in the reeler dentate gyrus, most postnatal cell proliferation occurs ectopically and in the hippocampus the normal "inside-out" sequence of neurogenesis is reversed, the earliest pyramidal cells generated coming to lie superficially within the stratum pyramidale and the later formed cells being added at progressively deeper levels. There is no discernible gradient in the time of origin of the granule cells in the radial dimension of the reeler dentate gyrus, whereas there is an obvious "outside-in" gradient in the normal animal. The characteristic gradients in cell proliferation seen in the transverse and longitudinal dimensions of the normal dentate gyrus are, however, also evident in the reeler mouse. Taken together, these observations suggest that the reeler gene exerts its effect on neuronal position only in the radial dimension, and does so at a stage of development subsequent to the proliferation and initial migration of the relevant neurons. Timm's sulfide silver preparations indicate that the characteristic staining patterns seen in the dentate gyrus and hippocampus appear at the same time, and mature at the same rate in normal and reeler mice.

Animals↗
PubMed2006

Human embryoid body-derived stem cells in tissue engineering-enhanced migration in co-culture with bladder smooth muscle and urothelium.

OBJECTIVES: To evaluate the affinity between human stem cells and human bladder cells by analyzing their migration and proliferation patterns in co-culture. Human stem cells have great potential for tissue engineering purposes. Co-culture of stem cells with mature cells may promote differentiation. METHODS: Equal numbers of green fluorescent protein-labeled human embryonic germ cell derivates (SDECs) were plated, either alone or in the presence of red fluorescence-labeled (PKH 26) human bladder smooth muscle cells (SMCs) or urothelial cells (UROs). The co-cultures shared the same media (EGM2MV). The migration patterns of the different cell lines were measured daily, using an integrated grid, for 8 days with fluorescence microscopy. RESULTS: SDECs, grown alone, had a robust basal migration rate of between 0.3 and 0.7 mm/day compared with SMCs, which had a rate of 0.1 to 0.3 mm/day and UROs with a rate of 0.1 to 0.2 mm/day. Stem cell migration was enhanced in co-culture with SMCs or UROs to 0.5 to 1.0 mm/day. Migration of SDECs was more linear, directed toward SMCs or UROs, compared with the circumferential growth when plated alone. SMCs, more than UROs, migrated more rapidly in the presence of stem cells. CONCLUSIONS: Human stem cells showed improved migration in the presence of mature human bladder cells and were attracted to them, as shown by the altered direction of growth. Thus, co-culture of human stem cells with host SMCs can enhance seeding of matrices due to positive chemotaxis. Identifying the responsible factors may help to augment chemotaxis between desired cell types and optimize tissue regeneration.

Cell Movement↗
PubMed2005

Selective modulation of integrin-mediated cell migration by distinct ADAM family members.

A disintegrin and a metalloprotease (ADAM) family members have been implicated in many biological processes. Although it is recognized that recombinant ADAM disintegrin domains can interact with integrins, little is known about ADAM-integrin interactions in cellular context. Here, we tested whether ADAMs can selectively regulate integrin-mediated cell migration. ADAMs were expressed in Chinese hamster ovary cells that express defined integrins (alpha4beta1, alpha5beta1, or both), and cell migration on full-length fibronectin or on its alpha4beta1 or alpha5beta1 binding fragments was studied. We found that ADAMs inhibit integrin-mediated cell migration in patterns dictated by the integrin binding profiles of their isolated disintegrin domains. ADAM12 inhibited cell migration mediated by the alpha4beta1 but not the alpha5beta1 integrin. ADAM17 had the reciprocal effect; it inhibited alpha5beta1- but not alpha4beta1-mediated cell migration. ADAM19 and ADAM33 inhibited migration mediated by both alpha4beta1 and alpha5beta1 integrins. A point mutation in the ADAM12 disintegrin loop partially reduced the inhibitory effect of ADAM12 on cell migration on the alpha4beta1 binding fragment of fibronectin, whereas mutations that block metalloprotease activity had no effect. Our results indicate that distinct ADAMs can modulate cell migration mediated by specific integrins in a pattern dictated, at least in part, by their disintegrin domains.

ADAM Proteins↗
PubMed1987

Interdigestive contractile patterns of the ileum in dogs.

The aim of this study is to elucidate the nature of ileal interdigestive contractile patterns by the computerized analysis of the contraction spread and by videofluoroscopy. Conscious dogs equipped with closely spaced strain-gauge force transducers were used. Two patterns of repetitive, phasic contractions were recorded, migrating clusters and phase IIIs; both patterns consisted of repetitive, propagated contractions. Both patterns migrated aborad by sequential movement of contraction waves down the bowel. Consequently, the rate of migration of either of the entire patterns was slower than the propagation velocity of constituent, individual contraction waves. Both patterns differed in several parameters, especially the propagated contractions of the clusters spread over shorter distances (1.47 +/- 0.4 cm) than those of phase III (4.65 +/- 0.99 cm). Compared with these complex patterns, propagating power contractions represented single contractions that propagated aborad at the same velocity as the contraction waves of the complex patterns. All three patterns propelled luminal contents distally.

Animals↗
PubMed2005

Osteoblast alignment, elongation and migration on grooved polystyrene surfaces patterned by Langmuir-Blodgett lithography.

Topographically patterned surfaces are known to influence cellular behavior in a controllable manner. However, the relatively large surface areas (several cm2) required for many biomaterial applications are beyond the practical limits of traditional lithography. Langmuir-Blodgett lithography, a recently developed method, was used to fabricate regularly spaced grooves of different depths (50 and 150 nm) with a periodicity of 500 nm over several square centimeter on silicon surfaces. These topographies were transferred into polystyrene surfaces by means of nanoimprinting. Primary osteoblasts were cultured on the patterned polymer surfaces. They were observed to align, elongate and migrate parallel to the grooves. The combination of Langmuir-Blodgett lithography with nanoimprinting enables the fabrication of large, nanostructured surface areas on a wide spectrum of different biomaterials. Osteoblasts show a significant anisotropic behavior to these surfaces, which can enhance cell settlement on the surface or be used to direct tissue generation on the biomaterial interface.

Actinin↗
PubMed2003

Intraduodenal serotonin elicits non-propagating spike potentials in the small intestine of the rat.

Serotonin (5-hydroxytryptamine, 5-HT) is an endogenous signalling molecule capable of altering small intestinal motility. Serotonin is normally present in the intestinal lumen and released by enterochromaffin cells of the mucosal epithelium. We found that intraduodenal infusion of exogenous serotonin causes a dose-dependent myoelectric response in the smooth muscle of the small intestine in the conscious rat. The response consists of repetitive bursts of action potentials (RBAP) that are characterized as short bursts of non-propagative myoelectric spiking. RBAP occur intermittently and only during the first 15 min after intralumenal serotonin infusion. After the initial 15 min period, the frequency of RBAP declines, and the myoelectric pattern shifts to prolonged and continuous spiking, eliminating the interdigestive migrating myoelectric pattern. The effects of intralumenal serotonin are not replicated by parenteral or intraperitoneal infusion nor by intralumenal infusion of 5-hydroxytryptophan or 5-hydroxyindoleacetic acid. The response to intralumenal serotonin was eliminated by several specific 5-HT receptor antagonists. On repeated intralumenal administration of serotonin, the RBAP response decreased demonstrating a decreased sensitivity of the muscle contraction on re-exposure to serotonin. We conclude that intralumenal infusion of serotonin can temporarily initiate specific small intestinal muscle events that are not generated by serotonin from other non-lumenal administration sites. We speculate that an afferent neuro-pathway is necessary for the induction of RBAP, since RBAP are not observed from in vitro muscle preparations.

Action Potentials↗
PubMed2003

Are colonic regular contractile frequency patterns in slow transit constipation a relevant pathophysiological phenomenon?

BACKGROUND: Pathogenesis of slow transit constipation still remains elusive. Some studies have shown several colonic motor abnormalities; however, it is not easy to understand the relative importance of the single ones. AIMS: Since it has been hypothesized that an excess of periodic distal motor activity may be of pathophysiological importance in patients with slow transit constipation, we evaluated regular colonic contractile frequencies in a homogeneous cohort of these patients. PATIENTS: A total of 26 female patients (age range 34 to 67 years) fulfilling the Rome II criteria for constipation entered the study. No patient had evidence of secondary forms of constipation and distal obstruction. METHODS: Twenty-four hour colonic manometric studies were obtained for each patient. Regular contractile patterns (with frequencies ranging from 2 to 8 cycles/min) were calculated for the entire recording period and in single colonic segments. RESULTS: Overall, regular patterns accounted for about 3% of the total colonic motor activity (average 30 min/day per subject), with the 3 cycles/min being the predominant contractile rhythm. Most of this activity was present in the sigmoid colon, accounting for >50% of the total amount of motility, and it was more prevalent than in the descending and transverse colon; no differences were revealed in the descending with respect to the transverse colon. No daily fluctuations of regular contractile activity, nor a cyclic pattern, nor migration between recording points were observed. CONCLUSIONS: Regular colonic frequency patterns are probably of minor pathophysiological importance in slow transit constipation, even in the light of the scant amount of such phenomena previously documented in healthy subjects.

Adult↗
PubMed1983

[The emigration of French Canadians to the United States, 1790-1940: a conceptual framework and some quantitative guesses].

"Using a Faucher-Dales approach to migration phenomena, the authors sketch a plausible scenario of the pattern of migration of French Canadians to the United States [from 1790 to 1940] as regulated by the size of the differential economic rent. Making use of all available data, the authors show that this approach would appear to be vindicated to the extent that the scenario it suggests is compatible with the available estimates of the migration flows." (summary in ENG)

Americas↗
PubMed1990

The context of migration: the example of Ireland in the nineteenth century.

"A classic case where out-migration interacted with many other geographical phenomena is provided by rural Ireland in the nineteenth century. The apparent turning point was the Great Famine of the 1840s, but the areas with the greatest suffering from starvation did not necessarily show the greatest population decline, suggesting that other forces were active. Considerable economic and social changes were already taking place before the Famine: fertility was being reduced, later marriage was becoming established and considerable emigration was already taking place. Immediately after the Famine those areas which had been hardest hit often reverted to pre-Famine conditions and did not show strong population decline until the 1870s. The Famine was a most serious event, but the modernization of Irish rural life, which linked emigration with changes in family structure, agriculture and population numbers, was more important in bringing about geographical change."

Conservation of Natural Resources↗
PubMed1996

Migration of cemented femoral components after THR. Roentgen stereophotogrammetric analysis.

We studied the migration of 58 cemented Hinek femoral components for total hip replacement, using roentgen stereophotogrammetric analysis over four years. The implants migrated faster during the first year than subsequently, and the pattern of migration in the second period was very different. During the first year they subsided, tilted into varus and internally rotated. After this there was slow distal migration with no change in orientation. None of the prostheses has yet failed. The early migration is probably caused by resorption of bone damaged by surgical trauma or the heat generated by the polymerisation of bone cement. Later migration may be due to creep in the bone cement or the surrounding fibrous membrane. The prosthesis which we studied allows the preservation of some of the femoral neck, and comparison with published migration studies of the Charnley stem suggests that this decreases rotation and may help to prevent loosening.

Adult↗