Patterns of migration propensity for black and white American men. Evidence from a cohort analysis.
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Adolescent↗
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Cell patterning in migrating slugs of Dictyostelium discoideum.
When front quarters of migrating slugs of Dictyostelium discoideum are isolated by surgery and induced to friut immediately they produce fruiting bodies with disproportionately large stalks (Raper, 1940). The data in this communication show that the 'stalky' character of fruits derived from front quarters persists even if the cells of the front quarter are disaggregated and hence to reaggregate before fruiting. The data also demonstrate that friuts derived from rear quarters of slugs have disproportionately large spore heads, and that this effect becomes more pronounced with increasing age of the slugs. These observations support the view that the cells of the front and rear of migrating slugs are to some extent committed to different fates.
Cell Differentiation↗
Diversity of some gene frequencies in European and Asian populations. V. Steep multilocus clines.
Regions of abrupt genetic change, which result from either rapid spatial change of selective pressures or limited admixture, were investigated in Europe and Asia on the basis of eight red cell markers typed in 960 samples. Two methods were employed, one based on genetic distances and one on evaluation of the first derivative of the surfaces representing allele-frequency variation. Genetic divergence tends to be maximal between populations that are separated by physical factors (mountain ranges and seas) but also separated by cultural barriers (different language affiliation). This suggests that mating isolation, rather than adaptive response to environmental change, accounts for spatially abrupt genetic change at the loci studied and that cultural differences associated with language contribute to isolating populations. Although selection may have determined two wide allele-frequency gradients, the genetic structure of European and Asian populations seems primarily to reflect isolation by distance when investigated on a small scale and migration patterns (or absence of migration) when investigated on a larger scale.
Alleles↗
Early patterns of migration, morphogenesis, and intermediate filament expression of subventricular zone cells in the postnatal rat forebrain.
Recent studies using retroviral labeling of subventricular zone (SVZ) progenitors in vivo in neonatal rats have directly demonstrated the generation of both astrocytes and oligodendrocytes from these progenitors. In the present study, we used a recombinant retroviral vector encoding beta-galactosidase, and analyzed brains within the first week after retroviral injection to trace the early routes that SVZ cells take as they migrate into white matter and cortex and characterized the early morphological and antigenic changes that accompanied their differentiation. SVZ cells follow specifically definable migratory routes as they colonize the cortex and subcortical white matter. Glial progenitors do not populate the cortex in a systematic, laminar fashion, as do neuroblasts. The abundance of labeled progenitors in radial arrangements and the close apposition of many immature cells to vimentin+ radial glial processes, suggest that glial progenitors migrate along radial glia. Labeled SVZ cells, which displayed a simple, unipolar or bipolar morphology, lacked detectable vimentin and nestin intermediate filaments. Similarly, beta-galactosidase-positive cells in white matter lacked these filaments. In contrast, labeled, multipolar cells in the cortex, and a few of the immature-appearing cortical cells expressed nestin and vimentin. At these early time points, GFAP was not detected in beta-galactosidase-labeled cells. Multipolar cells in cortex frequently displayed processes extending toward and contacting blood vessels. These observations suggest that the expression of nestin and vimentin occurs after progenitors emigrate from the SVZ and that filament expression and contact with blood vessels represent an early stage of astrocyte differentiation.
Animals↗
Changing patterns of migration between metropolitan and nonmetropolitan areas in the United States: recent evidence.
Data from the 1975 Current Population Survey confirm that, during 1970-1975, there was a reversal of the traditional net migration stream between metropolitan and nonmetropolitan areas in the United States. During this period, there was net in-migration of 1,600,000 persons to nonmetropolitan areas, in contrast to net out-migration of 350,000 persons from these areas in 1965-1970. Reversal was caused by a 12 percent decrease in the number of nonmetropolitan out-migrants and a 23 percent increase in the number of SMSA residents moving to nonmetropolitan territory over 1965-1970 levels. While some changes in the size of migration streams were due to changes in age structures and population bases in metropolitan and nonmetropolitan areas, they were caused primarily by real shifts in out-migration propensities at practically all ages in both areas.
Age Factors↗
Relationship between pattern of cell migration from the germinal layer and changing patterns of differentiation in the lizard epidermis.
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Animals↗
Lymphocyte traffic and the skin.
Lymphocyte migration patterns into and within lymphoid organs and nonlymphoid organs such as the skin as highly regulated and controlled by a variety of factors, some of which we are beginning to understand at a basic cellular and molecular level. In the case of lymphocyte migration into lymphoid organs, recirculatory patterns and preferences appear to be mediated by selective recognition via lymphocyte membrane receptors of distinctive determinants expressed by specialized endothelial cells in different organ sites. A similar model in which endothelial cells in the skin share common determinants with endothelial cells in peripheral lymph nodes can be developed to explain the migration patterns of lymphocytes from the blood into the skin. Cells that have undergone blast transformation in the microenvironment of the skin or peripheral lymph nodes, or both, appear to recirculate selectively within this particular sphere of immunologic influence, whereas other cells that undergo this transformation in the microenvironment of the gastrointestinal tract and its draining mesenteric lymph nodes selectively recirculate within that sphere of immunologic influence. This preferential recirculation increases the probability that the immunologic defense needs of a given region or tissue such as the skin will be met efficiently and appropriately. Finally, some of the phenotypic characteristics favoring the movement of lymphocytes from the bloodstream into the dermis (such as recent stimulation and the presence of T-cell surface markers) also seem to favor lymphocyte migration into or retention in the epidermis. However, under appropriate circumstances, epidermotropism can be exhibited by both major subsets of T cells as well as a variety of non-T cells.
Animals↗
Characterization of rotavirus electropherotypes excreted by symptomatic and asymptomatic infants.
Human rotavirus isolates from 1100 stool samples were analyzed by polyacrylamide gel electrophoresis, and 48 different migration patterns were detected. Heterogeneity in the migration of segment 10 was observed in both long and short electropherotypes in which three long and two short patterns were identified. In spite of these variations all short and long electropherotypes were subgrouped by enzyme immunoassay as subgroups I and II respectively. Mixed infections were detected in 17% of cases and the subgrouping correlated with the corresponding electropherotypes. The same electropherotypes were present in severe, mild and asymptomatic cases and no electropherotype was particularly associated with greater virulence. Furthermore, the electropherotypes isolated from nosocomial asymptomatic cases were the same as those detected from those admitted with severe diarrhea. It seems unlikely that electropherotyping can be used to identify more virulent strains of rotavirus.
Carrier State↗
Migrating interstitial cells differentiate into neurons in hydra.
Interstitial cell migration has been observed numerous times in grafted hydra, but the extent to which graft injuries might stimulate the migration of otherwise nonmotile cells was unknown. The present study describes the migration and differentiation of vital dye-labeled interstitial cells in intact, normal hydra. Interstitial cells, stained with a fluorescent vital dye, migrated away from a labeled patch of ectodermal cells and subsequently were found throughout the body column. Shortly thereafter, labeled neurons began to appear among the migrating cells. The number of migrating interstitial cells remained constant over 5 days, whereas the number of labeled neurons increased. Labeled interstitial cells and neurons accumulated primarily in the head and peduncle, as observed in previous studies of short-term migration patterns in grafted hydra. The present study shows that migration of interstitial cells occurs in normal nongrafted hydra and that the accumulation patterns parallel results from graft experiments. The population of migrating cells appears to be limited to neuron precursors.
Animals↗
The migration of Langerhans' cells into and out of lymph nodes draining normal, carcinogen and antigen-treated sheep skin.
Epidermal Langerhans' cell (LC) migration to the regional lymph node and beyond into central lymph was examined in sheep following topical application of the complete chemical carcinogen 7,12-dimethylbenz(a)anthracene (DMBA) or the contact sensitizing antigen 2,4,6-trinitrochlorobenzene (TNCB). This was facilitated by cannulating previously constructed pseudoafferent lymphatic vessels draining the skin treated with these agents or alternatively, the efferent lymphatic vessel of the regional lymph node. Application of DMBA resulted in a biphasic increase in LC migration. There was an initial increase in LC migration at 25 h with the maximum response (3.6 x 10(7) LC/h) occurring approximately 5 days after DMBA treatment. In contrast, the contact sensitizing antigen TNCB caused enhanced LC migration within minutes of the application of antigen (3.3 x 10(6) LC/h) and peak migration at 8-12 h. Examination of efferent lymph cells from the regional lymph node after DMBA treatment showed uncharacteristically large numbers of LC traversing the lymph node. These LC migration patterns suggest different mechanisms may trigger the migration of LC from skin after the application of DMBA to those associated with the normal processes of antigen presentation.
9,10-Dimethyl-1,2-benzanthracene↗
Mark-release-recapture studies with Aedes dorsalis (Diptera: Culicidae) in coastal northern California.
Two mark-release-recapture studies were conducted along the Sacramento-San Joaquin River Delta in northern California to describe the population ecology and dispersal pattern of Aedes dorsalis (Meigen). Immature Ae. dorsalis were collected from saline tidal marshes, reared to adults, marked, and released. Recapture grids during the July and September studies were within 8.0 and 2.4 km of the release sites, and recapture rates were 0.1 and 1.2%, respectively. The longest recorded flight was 5.8 km, and mosquitoes were recaptured up to 15 d after release. In September, 84% of the marked mosquitoes were recaptured within 2.0 km of the release site, and the mean dispersal distance was 1.9 km. Marked mosquitoes flew predominantly downwind to the east. There was no evidence that Ae. dorsalis traversed the 1.6-km-wide river from Contra Costa to Solano County. Temporal and spatial recapture patterns indicated a possible short-range migration pattern from oviposition sites to upland host-seeking areas. Changes in the recapture rate with cohort age delineated a 7-d gonotrophic cycle during September.
Aedes↗
RNA electropherotypes of human rotaviruses from North and South America.
Between April 1979 and December 1982, viral agents were found in 231 of 695 children admitted to the Texas Children's Hospital with gastroenteritis. Electron microscopic analysis showed that rotaviruses were the most common viral agents, and a seasonal pattern of rotavirus disease was observed. The migration patterns of the RNA segments of these rotaviruses on electrophoresis in polyacrylamide gels were compared with those of rotaviruses collected from other areas of the United States of America and from Argentina, Colombia and Mexico. A number of different RNA electropherotypes were found, including some patterns not previously reported.
Child↗
Schistosoma haematobium, S. intercalatum, S. japonicum, S. mansoni, and S. rodhaini in mice: relationship between patterns of lung migration by schistosomula and perfusion recovery of adult worms.
The development of five schistosome species was compared in mice by the recovery of schistosomula from chopped lung tissue and of adult worms by portal perfusion. Three developmental patterns appeared. (1) Schistosoma japonicum was unique in showing an early establishment of schistosomula in and a rapid departure from the lungs together with the highest worm recovery; (2) S. haematobium contrasted by establishing later and persisting in the lungs for at least 2 weeks while yielding the lowest adult worm recovery; and (3) S. intercalatum, S. mansoni, and S. rodhaini had an intermediate pattern--they resided in the lungs for several days, then disappeared and produced intermediate numbers of adults. Lung petechiae, known to accompany the migration of S. japonicum, were never detected after infection with the other species. We speculate that the three migration patterns of schistosomes are related to the size of the relative spectra of naturally infected definitive hosts.
Animals↗
Analysis of genetic structure and dispersal patterns in a population of sea beet.
A model of the migration pattern in a metapopulation of sea beet (Beta vulgaris L. ssp. maritima), based on the continuous distributions of seed and pollen movements, is fitted to gene frequency data at 12 isozyme and RFLP loci by maximum likelihood by using an approximation of the simultaneous equilibrium distribution of the gene frequencies generated by the underlying multivariate stochastic process of genetic drift in the population. Several alternative restrictions of the general model are fitted to the data, including the island model, a model of complete isolation, and a model in which the seed and pollen dispersal variances are equal. Several likelihood ratio tests between these alternatives are performed, and median bias in the estimated parameters is corrected by using parametric bootstrapping. To assess the fit of the selected model, the predicted covariances are compared with covariances computed from the data directly. The dependency of estimated parameters on the ratio between effective and absolute subpopulation sizes, which is treated as a known parameter in the analysis, is also examined. Finally, we note that the data also appear to contain some information about this ratio.
Alleles↗
Distinctive ribonucleic acid patterns of human rotavirus subgroups 1 and 2.
The ribonucleic acid migration patterns of 7 subgroup 1 and 16 subgroup 2 human rotaviruses recovered from four geographic areas were compared. The subgroup 1 ribonucleic acid patterns had strikingly slower-moving segments 10 and 11, suggesting a correlation between the ribonucleic acid pattern and the subgroup specificity.
Electrophoresis, Polyacrylamide Gel↗
Isolation of two human tumor epithelial cell lines from solid breast carcinomas.
Most of the available human breast tumor cell lines have been derived from pleural effusions. The two cell lines herein described, BT-474 and BT-483, were derived from solid, invasive ductal breast carcinomas. Both are epithelial and neoplastic as judged by their general morphology, their fine structure, and their ability to produce growing nodules in nude mice and colonies in soft agar and methocel. BT-474 and BT-483 are human as expressed by chromosome morphology and aneuploid with a modal number of 55 and 72 chromosomes, respectively. Trypsin-Giemsa banding did not reveal the presence of obvious HeLa markers, and the glucose 6-phosphate dehydrogenase electrophoretic migration pattern was of the B-type. Furthermore, the migration of lactic dehydrogenase, malic dehydrogenase, and 6-phosphogluconate dehydrogenase isoenzymes was consistent with a human pattern and different from that of the mouse, rat, or hamster. Quarterly tests to detect the presence of aerobic and anaerobic mycoplasmas were repeatedly negative. A culture medium containing insulin, increased amounts of amino acids, vitamins, and glucose facilitated the isolation of the tumor cells. Cell replication was maintained with 10% fetal calf serum absorbed with activated charcoal and dextran. No production of alpha-lactalbumin was detected by radioimmunoassays, but high levels of progesterone receptors were found in both cell lines.
Animals↗
Migration properties of circular DNAs using orthogonal-field-alternation gel electrophoresis.
The migration of a series of supercoiled plasmids ranging in size from 4 to 91 kilobases (kb) has been analyzed by orthogonal-field-alternation gel electrophoresis (OFAGE). These circular DNAs enter OFAGE gels and are resolved over the same region of the gel as linear DNAs from 260 to 2200 kb. Furthermore, a distinct triphasic migration pattern was observed for the supercoiled DNAs. The migration of plasmids between 6 and 20, and 60 and 91 kb is inversely proportional to size, whereas the mobilities of plasmids between 20 and 60 kb increase with size. Unlike linear DNA molecules, the relative mobilities of these plasmids are constant over a broad range of pulse times, from 10 to 120s. Electrophoresis of supercoiled, relaxed, and nicked open circular forms as well as topoisomers of small plasmids shows that the extent of supercoiling has a dramatic effect on plasmid migration on OFAGE. Several practical applications for exploiting the different migration properties of circular and linear DNA molecules on OFAGE are presented.
Animals↗
[Population structure of the forest Nentsi: demographic characteristics, marriage structure, migration and an analysis of mixing].
This report is a third one in a series of works devoted to the genetic structure (biodemographic studies) of the Forest Nentsy. The main parameters of the population studied were as follows: the total number in seven subpopulations amounting to 1734 persons, the sex ratio 0.93, percentage of children in the group of 0 to 15 years old--39,1%, reproductive and effective sizes--29,5% and 22,0%, respectively, the mean number and variance of offspring per mating, when reproduction is completed being 2,7 (5,2). It has been shown that kin and territorial subdivision of the population contributes to the formation of conjugal pairs and migration pattern. Within-kin matings make 0,041, whereas, according to the panmixia hypothesis, this value would be 0,243. The average index of isolation for particular subpopulation is 62,7%. An exchange of migrants occurs between adjacent groups. Migration stream to the different subpopulations varies in volume and ethnic composition. Analysis of the admixture based on the pedigree isoname method has shown that the proportion of the Forest Nentsy gene contribution to their own population is 74,4%. Data on subpopulation size, patterns of matings, migration and admixture may serve as a basis to account for intrapopulation heterogeneity.
Adolescent↗