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PubMed1984

Changing patterns of migration to Australia and their influence on the health of migrants.

Whilst before World War II migration to Australia was almost entirely from the British Isles, over 60% of post-War II migrants came from other countries other than Britain. They arrived in Australia in distinct waves: Eastern European refugees were followed by migrants from Western Europe, who were later replaced by migrants from the Mediterranean Basin and finally by Asians, initially from the Indian subcontinent, afterwards from Lebanon and most recently from Indo-China. These patterns of migration were changing the numerical size, age distribution and length of residence in Australia of the different ethnic groups. The paper describes the influence of these changes on physical and mental health of the migrants. Physical morbidity was related to 'imported diseases', to the different physical and social environment and to differences and changes in eating and other habits. Psychiatric disorders were associated with traumatic experiences encountered prior to migration, and with stresses of migration and adjustment to the new country. Thus, in evaluating the health of immigrants, one has to take into account the sources from which the migrants were drawn, their situation in the host society, their numerical growth and age distribution, as well as acculturation to the country settlement.

Adolescent↗

PubMed1998

Cytokines stimulate matrix metalloproteinase production by human pulp cells during long-term culture.

Interleukin-1 and tumor necrosis factor-alpha are inflammatory cytokines that are known to be potent stimulators of mineralized tissue resorption. One of the mechanisms by which these cytokines induce this loss is through the stimulation of matrix metalloproteinase (MMP) production and secretion by the host cells present at the inflammatory site. We have previously shown that these cytokines have little effect on MMP production by human pulp cells in short-term culture (24 to 48 h). In this study, we examined the production of MMPs by human pulp cells in the presence and absence of interleukin-1 and tumor necrosis factor-alpha in long-term cultures (2 to 16 days) using substrate gel zymography. The major band present in all samples examined migrated at 68 kDa, corresponding to the migration pattern of MMP-2, whereas a minor band migrated at 90 kDa, corresponding to the migration pattern of MMP-9. In the presence of cytokines, elevated levels of MMP-2 and MMP-9 were apparent at days 9 through 16. In addition, a band migrating at 110 kDa was present. This study demonstrates that cytokines stimulate the production of elevated levels of MMPs by human pulp cells in long-term cultures and that these MMPs may play a role in pulpal inflammation.

Cells, Cultured↗

PubMed1988

Identity--lost and found: patterns of migration and psychological and psychosocial adjustment of migrants.

This paper focuses on patterns of integration in migrant individuals and families. The level of adjustment in traditional and Westernized families has been examined. Different factors affecting adjustment are pointed out. Migration process is interpreted as a transient and necessary crisis situation. Risk factors in the acculturation crisis are reported and predictive and preventive measures are suggested. Characteristics of migrant and remigrant groups are compared. The role of "homesickness" in clinical symptom formation is discussed.

Acculturation↗

PubMed2005

Conservation of genetic diversity in the Japanese Black cattle population by the construction of partially isolated lines.

In the Japanese Black cattle population, five genetically divergent sub-populations have played important roles as suppliers of breeding stocks to the entire breed. We supposed a situation where five lines were constructed from each of the five subpopulations, and applied to this set of lines a management plan to conserve genetic diversity. Assuming that the male migration pattern among the lines followed the island model, we assessed the optimum male migration rate and required male numbers in each line, satisfying the following three conditions simultaneously: (i) the rate of inbreeding in each line was below 0.01 per generation; (ii) at least 97% of the initial genetic diversity was preserved after 10 generations; and (iii) more than 50% of the genes in an initial line were retained in the line after 10 generations. We found that approximately one breeding male should be selected per year and one breeding male should be exchanged among the lines per generation in each line to satisfy these three conditions. Numerical analysis with the migration rates actually observed among the five subpopulations demonstrated that the initial genetic differentiation among the lines was rapidly decayed by an asymmetrical migration pattern. For a successful plan, migration among lines should be strictly managed.

Animals↗

PubMed1996

Regulated Breathless receptor tyrosine kinase activity required to pattern cell migration and branching in the Drosophila tracheal system.

Receptor tyrosine kinases (RTKs) are members of a diverse class of signaling molecules well known for their roles in cell fate specification, cell differentiation, and oncogenic transformation. Recently several RTKs have been implicated in cell and axon motility, and RTKs are known to mediate chemotactic guidance of tissue culture cells. We have investigated whether the Drosophila FGF receptor homolog, Breathless (BTL), whose activity is necessary for each phase of branching morphogenesis in the embryonic tracheal system, might play a role in guiding the directed migration of tracheal cells. We found that expression of a constitutively active receptor during tracheal development interfered with directed tracheal cell migration and led to extra secondary and terminal branch-forming cells. Reduction in endogenous BTL signaling enhanced the cell migration defects while suppressing the ectopic branching defects. These results are consistent with a model for tracheal development in which spatially regulated BTL activity guides tracheal cell migration and quantitatively regulated BTL activity determines the patterns of secondary and terminal branching cell fates.

Animals↗

PubMed2003

Stem cell-derived endothelial cells/progenitors migrate and pattern in the embryo using the VEGF signaling pathway.

Endothelial precursor cells respond to molecular cues to migrate and assemble into embryonic blood vessels, but the signaling pathways involved in vascular patterning are not well understood. We recently showed that avian vascular patterning cues are recognized by mammalian angioblasts derived from somitic mesoderm through analysis of mouse-avian chimeras. To determine whether stem cell-derived endothelial cells/progenitors also recognize global patterning signals, murine ES cell-derived embryoid bodies (EBs) were grafted into avian hosts. ES cell-derived murine endothelial cells/progenitors migrated extensively and colonized the appropriate host vascular beds. They also formed mosaic vessels with avian endothelial cells. Unlike somite derived-endothelial cells, ES cell-derived endothelial cells/progenitors migrated across the host embryonic midline to the contralateral side. To determine the role of VEGF signaling in embryonic vascular patterning, EBs mutant for a VEGF receptor (flk-1(-/-)) or a signal (VEGF-A(-/-)) were grafted into quail hosts. Flk-1(-/-) EB grafts produced only rare endothelial cells that did not migrate or assemble into vessels. In contrast, VEGF-A(-/-) EB grafts produced endothelial cells that resembled wild-type and colonized host vascular beds, suggesting that host-derived signals can partially rescue mutant graft vascular patterning. VEGF-A(-/-) graft endothelial cells/progenitors crossed the host midline with much lower frequency than wild-type EB grafts, indicating that graft-derived VEGF compromised the midline barrier when present. Thus, ES cell-derived endothelial cells/progenitors respond appropriately to global vascular patterning cues, and they require the VEGF signaling pathway to pattern properly. Moreover, EB-avian chimeras provide an efficient way to screen mutations for vascular patterning defects.

Animals↗

PubMed1996

Urban to urban migration: Soviet patterns and post-Soviet implications.

"In spite of extensive literature on migration in the Soviet Union, we know little about household-level decisions. This study specifies and estimates those variables important to understanding the migration decision. Using data from the Soviet Interview Project (SIP), we examine the forces influencing the decision to migrate or not to migrate, and in addition, for those who did migrate, the forces influencing the locational choices made. The results indicate that, while some of the traditional factors influencing migration are important, others are not, suggesting that in the post-Soviet era, differentiating the persistence of Soviet-type forces from emerging market-type forces will be important for an understanding of urban to urban migration."

Behavior↗

PubMed1997

Evidence for the involvement of 5-HT4 receptors in the 5-hydroxytryptamine-induced pattern of migrating myoelectric complex in sheep.

1. The effects induced by 5-hydroxytryptamine (5-HT) on gastrointestinal myoelectric activity in conscious sheep were recorded through electrodes chronically implanted and analysed by computer. The 5-HT receptors and the cholinergic neuronal pathways involved in these actions were investigated. 2. The intravenous (i.v.) administration of 5-HT (2, 4 and 8 micrograms kg-1 min-1, 5 min) induced an antral inhibition concomitant with a duodenal activity front that migrated to the jejunum, followed by a period of intestinal inactivity. This myoelectric pattern closely resembled that observed in the phases III and I of the migrating myoelectric complex (MMC) in sheep. The 0.5 microgram kg-1 min-1 dose evoked the same pattern in only two out of the six animals used. Likewise, the 1 microgram kg-1 min-1 dose similarly affected four of the six animals. In addition, a transient stimulation was observed in the antrum and jejunum when the two highest doses were used. 3. The 5-HT1 antagonist, methiothepin (0.1 mg kg-1), the 5-HT2 antagonists, ritanserin (0.1 mg kg-1) and ketanserin (0.3 mg kg-1), the 5-HT3 antagonists, granisetron (0.2 mg kg-1) and ondansetron (0.5 mg kg-1), as well as the 5-HT4 antagonist, GR113808 (0.2 mg kg-1), did not modify the spontaneous gastrointestinal myoelectric activity. However, the cholinoceptor antagonists, atropine (0.2 mg kg-1) and hexamethonium (2 mg kg-1), inhibited gastrointestinal activity. 4. When these antagonists were injected i.v. 10 min before 5-HT (2 or 4 micrograms kg-1 min-1, 5 min), only GR113808, atropine and hexamethonium were able to modify the 5-HT-induced actions, all of them being completely blocked by the three antagonists. 5. Our data show that 5-HT initiates a MMC-like pattern in the gastrointestinal area in sheep through 5-HT4 receptors. Furthermore, these actions are mediated by cholinergic neural pathways involving muscarinic and nicotinic receptors. However, our results do not indicate a role for either 5-HT1, 5-HT2 or 5-HT3 receptors in the 5-HT-induced effects.

Animals↗

PubMed1993

Migration of alveolar macrophages from alveolar space to paracortical T cell area of the draining lymph node.

In this report we studied the translocation of fluorescent particulate antigens to the draining lymph node, and the migration of fluorescent labeled alveolar macrophages (AM) and peritoneal macrophages (PM) in mice. The results show that intratracheally (IT) instilled particulate antigens translocate to the paracortical T cell area of the draining lymph node. When labeled AM were injected IT, they were found to migrate from the alveolar space into the paracortical T cell area of the draining lymph node. An identical localisation was found after IT injection of labeled PM. When either labeled AM, or PM were injected into the peritoneal cavity, a different migration pattern was observed. Via this route the labeled macrophages migrated to the subcapsular sinus and medulla of the draining lymph nodes. It is shown that the migrated cells are not dendritic cells (DC) present in the cell preparations. A possible role for the micro-environment of the injection site, and the significance of the specific migration pattern of AM is discussed.

Animals↗

PubMed2004

Movement pattern of the Exeter femoral stem; a radiostereometric analysis of 22 primary hip arthroplasties followed for 5 years..

BACKGROUND: The design of the Exeter stem may facilitate distal migration, but radiostereometric analysis (RSA) studies have been limited to 2 years of follow-up. PATIENTS AND METHODS: We followed migration of the Exeter femoral stems in 22 primary hip arthroplasties for 5 years with RSA. RESULTS: All stems migrated distally and the median migration at 2 years was 1.34 mm, while at 5 years it was 1.77 mm. 7 stems migrated above accuracy between 3 and 5 years. (RSA) evaluation of the cement mantle could be performed in 14 cases, and in 5 slight migration was found. Most of the stems rotated towards retroversion and the median rotation at 2 years was 1.2 degrees, while at 5 years it was 1.6 degrees. We found 1 patient with impending clinical failure but no deviation in the RSA migration pattern, and 1 patient with unstable migration pattern but no clinical symptoms. INTERPRETATION: We found a greater distal migration of the Exeter stem for longer periods of time than seen with other types of cemented implants.

Adult↗

PubMed1986

A reexamination of the O1 lipopolysaccharide antigen group of Escherichia coli.

A total of 64 Escherichia coli strains of the O1 serogroup were tested for the migration pattern of their lipopolysaccharides (LPS) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. O1:K1 and O1:K51 strains of the OMP5 outer membrane protein pattern possessed LPS with a doublet pattern (O1A1) or the lowermost band of the O1A1 doublet (O1A2). O1:K1 strains of the OMP9 pattern possessed LPS referred to as O1A, which corresponded to the uppermost band of the O1A1 doublet pattern. A few O1:K? strains possessed LPS of different migration patterns (O1B and O1C). O1A and O1A1 LPS were indistinguishable by chemical techniques, and both reacted with each of 10 different monoclonal antibodies tested. However, O1A1 had an additional epitope within the additional band in each doublet, as demonstrated by adsorption experiments with hyperimmune rabbit sera followed by Western blotting. Furthermore, purified polysaccharide from O1A bacteria was incapable of inhibition in enzyme-linked immunosorbent assays performed with O1A1 LPS as antigen and adsorbed, specific anti-O1A1 antibodies, whereas O1A1 polysaccharide inhibited this reaction. O1B and O1C LPS differed in all respects tested, including chemical composition, from O1A and O1A1 LPS.

Animals↗

PubMed2000

Patterns of migration and regulation of trunk neural crest cells in zebrafish (Danio rerio).

Regulation is the replacement of lost, undifferentiated embryonic cells by neighboring cells in response to environmental signals. Neural crest cells, embryonic cells unique to craniates, are good candidates for studies of regulation because they are pluripotent, and thus might be able to alter their behavior in response to environmental signals. This study investigated regulation for the loss of trunk neural crest (TNC) cells, specifically pigment derivatives, in the zebrafish, Danio rerio. The first part of the study clarifies and extends what has previously been described on normal patterns of TNC migration and differentiation. These data were then used to address the hypothesis that there is regulation for loss of TNC, and that regulation would vary with the amount removed, the position or stage of removal. Zebrafish TNC cells are large and numerous. SEM and Dil labeling revealed that TNC cells undergo several successive waves of 'sheet' and 'segmental' migration, beginning as early as the 12 somite stage. Dil-labeled TNC cells often migrated several somite lengths anteriorly and posteriorly along the trunk axis to form glial cells, ganglia, pigment, ectomesenchyme and tail reticular cells. Regulation occurred on a sliding scale, ranging from complete to incomplete. Defects in development and/or pigmentation occurred if large regions of TNC cells were removed, or if cells were removed from anterior (cardiac) and posterior (tail) extremities of the trunk. Melanophores were the cell type most visibly affected by TNC extirpations. Otherwise, pigmentation was remarkably normal. We propose that the completeness of regulation largely depends upon healing of the overlying epidermis.

Animals↗

PubMed1999

Identification of tissues and patterning events required for distinct steps in early migration of zebrafish primordial germ cells.

In many organisms, the primordial germ cells have to migrate from the position where they are specified towards the developing gonad where they generate gametes. Extensive studies of the migration of primordial germ cells in Drosophila, mouse, chick and Xenopus have identified somatic tissues important for this process and demonstrated a role for specific molecules in directing the cells towards their target. In zebrafish, a unique situation is found in that the primordial germ cells, as marked by expression of vasa mRNA, are specified in random positions relative to the future embryonic axis. Hence, the migrating cells have to navigate towards their destination from various starting positions that differ among individual embryos. Here, we present a detailed description of the migration of the primordial germ cells during the first 24 hours of wild-type zebrafish embryonic development. We define six distinct steps of migration bringing the primordial germ cells from their random positions before gastrulation to form two cell clusters on either side of the midline by the end of the first day of development. To obtain information on the origin of the positional cues provided to the germ cells by somatic tissues during their migration, we analyzed the migration pattern in mutants, including spadetail, swirl, chordino, floating head, cloche, knypek and no isthmus. In mutants with defects in axial structures, paraxial mesoderm or dorsoventral patterning, we find that certain steps of the migration process are specifically affected. We show that the paraxial mesoderm is important for providing proper anteroposterior information to the migrating primordial germ cells and that these cells can respond to changes in the global dorsoventral coordinates. In certain mutants, we observe accumulation of ectopic cells in different regions of the embryo. These ectopic cells can retain both morphological and molecular characteristics of primordial germ cells, suggesting that, in zebrafish at the early stages tested, the vasa-expressing cells are committed to the germ cell lineage.

Animals↗

PubMed1988

Patterns of femoral head migration in osteoarthritis of the hip: a reappraisal with CT and pathologic correlation.

Although medial, superior, and axial patterns of migration of the femoral head in osteoarthritis of the hip have been well described, it is not clear what anatomic and biomechanical factors determine the direction of migration. The authors studied 22 patients with bilateral (11 patients) or unilateral (11 patients) osteoarthritis by means of conventional radiography and computed tomography (CT) to define any relationships between migration in the coronal plane and that in the transverse plane and to determine whether femoral anteversion, acetabular anteversion, femoral neck-shaft angle, or acetabular inclination were related to particular migration patterns. Anterior migration was evident in 14 of the 19 hips with a superior migration pattern, whereas posterior migration was present in five of the seven hips with a medial migration pattern. In the remainder of cases, no migration in the transverse plane was present. Femoral anteversion as determined with CT, femoral neck-shaft angle, angle of acetabular inclination, and acetabular anteversion angle in this relatively small sample were all found to be within normal limits and appeared to have no influence on the occurrence of a specific pattern of femoral head migration.

Aged↗

PubMed2005

Guidance of trunk neural crest migration requires neuropilin 2/semaphorin 3F signaling.

In vertebrate embryos, neural crest cells migrate only through the anterior half of each somite while avoiding the posterior half. We demonstrate that neural crest cells express the receptor neuropilin 2 (Npn2), while its repulsive ligand semaphorin 3F (Sema3f) is restricted to the posterior-half somite. In Npn2 and Sema3f mutant mice, neural crest cells lose their segmental migration pattern and instead migrate as a uniform sheet, although somite polarity itself remains unchanged. Furthermore, Npn2 is cell autonomously required for neural crest cells to avoid Sema3f in vitro. These data show that Npn2/Sema3f signaling guides neural crest migration through the somite. Interestingly, neural crest cells still condense into segmentally arranged dorsal root ganglia in Npn2 nulls, suggesting that segmental neural crest migration and segmentation of the peripheral nervous system are separable processes.

Animals↗

PubMed1982

Porcine pararotavirus: detection, differentiation from rotavirus, and pathogenesis in gnotobiotic pigs.

Some characteristics of a newly recognized porcine enteric virus are described. Tentatively, the virus was referred to as porcine pararotavirus (PaRV) because it resembled rotaviruses in respect to size, morphology, and tropism for villous enterocytes of the small intestine. However, it was antigenically distinct from porcine, human, and bovine rotaviruses and reoviruses 1, 2, and 3, and the electrophoretic migration pattern of PaRV double-stranded RNA was distinct from the electrophoretic migration patterns of the rotaviral and reoviral genomes. By passage in gnotobiotic pigs, PaRV was isolated from two suckling diarrheic pigs originating from two herds. After oral exposure of gnotobiotic pigs, villous enterocytes of the small intestines became infected as judged by immunofluorescence, resulting in villous atrophy and diarrhea. Mortality was high when gnotobiotic pigs less than 5 days old were infected. The C strain of this virus was serially passed 10 times in gnotobiotic pigs, and electron microscopy, immunofluorescence, and serological tests indicated no extraneous agents. The virus was serially passed five times in cell cultures which contained pancreatin in the medium, but replication was negligible or absent, as the number of immunofluorescent cells decreased with each passage. Since rotaviral infections are frequently diagnosed by direct electron microscopy of fecal specimens, the presence of other morphologically similar viruses, such as PaRV, should be considered. The use of immune electron microscopy is suggested as a means of helping recognize this situation.

Animals↗

PubMed1997

Migration and the life course: is there a retirement transition?

"This paper focuses on pre-elderly (ages 55-64) net migration in the United States for the period 1980-90, to explore the hypothesis that there exists a ¿retirement transition' that characterizes pre-elderly migration.... This research uses ordinary least squares regression to compare the effects of demographic, economic, and amenity factors on county-level net migration rates for five age groups: the young (25-44), the middle-aged (45-54), the pre-elderly (55-64), the young-old (65-74), and the old-old (75+). Pre-elderly migration patterns emerge as distinct from those of both younger and older age groups. Their net migration patterns are not fully shaped by labour force considerations. At the same time, pre-elderly migration appears to be driven by factors beyond retirement. These findings are discussed in the context of life-course change and their implications for the ageing baby-boom cohorts [considered]."

Age Factors↗

PubMed1988

Rotavirus epidemiology in Vellore, south India: group, subgroup, serotype, and electrophoretype.

Rotaviruses were detected in 163 of 916 (17.8%) specimens collected from children under 3 years of age with gastroenteritis in Vellore, South India, between August 1983 and July 1985. Rotaviruses were detected throughout the study period, with a peak prevalence in December to February (winter) and June to August (southwest monsoon season). A total of 117 rotavirus strains were tested for subgroup, serotype, and rotavirus double-stranded RNA electrophoretic migration pattern; 24.8% of the strains were subgroup I, 69.2% were subgroup II, and 6.0% were neither subgroup I nor subgroup II. Subgroup I and II strains were circulating concurrently throughout the study. Of the 117 rotavirus strains, 32 (27.4%) were serotyped; 15 were serotype 1, 3 were serotype 2, 2 were serotype 3, and 12 were serotype 4. Three serotypes were circulating concurrently during the periods of peak rotavirus prevalence. In 100 of the 117 strains (85.4%) an RNA pattern was detected. One unusual subgroup I group A rotavirus with a long migration pattern and four atypical rotaviruses serologically related to group C were also detected.

Child↗