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PubMed1990

Timing and patterns of astrocyte migration from xenogeneic transplants of the cortex and corpus callosum.

The timing, pattern, and pathway of astrocyte migration were investigated in vivo by transplantation of CD-1 mouse cerebral cortex (E13-14) or corpus callosum (P2-3) into neonatal rat cortex. A monoclonal antibody specific for a mouse astrocyte surface antigen (M2) was used to identify the location of the grafts and the migrated donor astrocytes. Within the host cortex, astrocytes from cortical grafts began migration at post-transplantation day (PTD) 7. Over the next 4 days, the most distant displaced donor cells were found progressively further away from the grafts, migrating at a rate of about 220 microns/day. After PTD 11, the migration rate for the farthest displaced donor cells slowed to 25 microns/day, and the cells appeared to stop at about PTD 16 at a distance of 1,100 microns from the edge of the graft. Astrocytes had a faster migration speed in the white matter and covered a longer distance (5 mm) than those in the gray matter, extending on occasion into the contralateral hemisphere. The patterns of astrocyte migration differed depending on local cues around the transplant. Donor astrocytes that had been implanted into the host cortex migrated toward the host cortical surface, sometimes in several radial lines. Astrocytes from grafts, especially callosal grafts, placed in the subcortical white matter migrated along the host fiber tracts. Many astrocytes transplanted into the hippocampus formed laminar patterns close to the hippocampal neuronal layers. These results suggest that the direction, pattern, and speed of astrocyte migration are influenced by local substrates in the host brain.

Animals↗

PubMed1990

Elderly Hispanic migration in the United States.

The specific aim of this study was to extend the analysis of migration patterns to Hispanics (Mexican, Cuban, Puerto Rican, and Other Hispanic) over the age of 60. The 1980 Census public use sample provided the data for this study, which was structured by four research expectations derived from features of the Hispanic population and from migration concepts. First, because of population growth, migration from abroad was expected to be heavy, and about half came from abroad. Second, because of the pattern of Hispanic population concentration and the different settlement patterns of the four subgroups, a relatively small migration system with distinct subsystems for the four nationality groups was expected and found. Florida is the major ethnomagnet. Third, traditional family values, as reflected in dependent living arrangements, were expected to be more prevalent among migrants from abroad, and they were. Finally, returning to one's state of birth was highest among Mexican interstate migrants, as expected.

Aged↗

PubMed1991

Patterns of epithelial migration in the unaffected ear in patients with a history of unilateral cholesteatoma.

Epithelial migration in a centrifugal manner is an established phenomenon in the normal human tympanic membrane. This pattern of migration is symmetrical in both ears of any one individual. We present a prospective study on the pattern of tympanic ink dot migration on the normal drum, in patients with a history of cholesteatoma in one ear. It was demonstrated that patients who develop cholesteatoma have a normal migratory pattern and rate in the unaffected ear. The conclusion from this study is that defective migration is not the initiating factor in the development of acquired cholesteatoma.

Cell Movement↗

PubMed1985

Homozygosity, effective number of alleles, and interdeme differentiation in subdivided populations.

The amount and pattern of genetic variability in a geographically structured population at equilibrium under the joint action of migration, mutation, and random genetic drift is studied. The monoecious, diploid population is subdivided into panmictic colonies that exchange migrants. Self-fertilization does not occur; generations are discrete and nonoverlapping; the analysis is restricted to a single locus in the absence of selection; every allele mutates to new alleles at the same rate. It is shown that if the number of demes is finite and migration does not alter the deme sizes, then population subdivision produces interdeme differentiation and the mean homozygosity and the effective number of alleles exceed their panmictic values. A simple relation between the mean probability of identity and the mean homozygosity is established. The results apply to a dioecious population if the migration pattern and mutation rate are sex independent.

Alleles↗

PubMed1990

Enzymatic heterogeneity of seminomas.

Heterogeneity of placental-like alkaline phosphatase (PLAP-like enzyme) in seminoma was studied. PLAP-like enzyme from seminoma tissues was separated into three areas with different proportions between tumors, while PLAP and PLAP-like enzymes in normal testes were separated into two areas on the basis of hydrophobicity. By use of lectin affinity chromatography, PLAP-like enzyme in seminoma revealed extra sugar chains compared to PLAP, indicating heterogeneity of the carbohydrate moiety. However, the glycosylation patterns were found to be essentially similar between seminoma and normal testis. On isoelectric focusing, differences in migration patterns of PLAP-like enzyme were revealed between seminoma and normal testis as well as between PLAP-like enzyme and PLAP. The differences in charge were mainly due to differences in sialylation of the molecules. The complex pattern on isoelectric focusing was not altered by neuraminidase treatment, indicating a considerable charge heterogeneity within the population of PLAP-like enzyme molecules from seminoma.

Alkaline Phosphatase↗

PubMed1991

Characterization of seminoma-derived placental-like alkaline phosphatase.

Characteristics of placental-like alkaline phosphatase (PLAP-like enzyme) in seminoma was studied. By use of lectin affinity chromatography, PLAP-like enzyme in seminoma revealed extra sugar chains compared to placental alkaline phosphatase (PLAP), indicating heterogeneity of the carbohydrate moiety. However, the glycosylation patterns were found to be essentially similar between seminoma and normal testis. On isoelectric focusing, differences in migration patterns were revealed between seminoma-derived and normal testis-derived PLAP-like enzyme as well as between PLAP-like enzyme and PLAP. The differences in charge were mainly due to differences in sialylation of the molecules. The complex pattern of PLAP-like enzyme from seminoma on isoelectric focusing was not altered by neuraminidase treatment, indicating a considerable charge heterogeneity within the population of the enzyme molecules from the tumor.

Alkaline Phosphatase↗

PubMed1975

The different migratory characteristics of lymphocyte populations from a whole spleen transplant.

Spleens from AS x BN donor rats labelled in vivo by multiple doses of [3H]thymidine were transplanted into syngeneic recipients by anastomosis to the abdominal great vessels. The recipients were killed 1-5 days after receiving the whole spleen transplants and the numbers and location of the [3H]thymidine-labelled cells which had migrated from the labelled donor spleen traced by means of autoradiographs of sections, imprints and smears of various recipient lymphoid tissues. These results were compared with the migration pattern of labelled dissociated spleen cell suspensions injected intravenously. The latter consists almost entirely of small lymphocytes which migrate to T or B areas of recipient spleen, lymph nodes and Peyer's patches. The labelled whole spleens also contained cells which migrated to the T and B areas of recipient lymphoid tissues, but in addition contained many lymphoid cells which migrated to the red pulp of the recipient spleen and to the lamina propria of the gut. These experiments showed, therefore, that the spleen contains mobile elements which have not been detected by transfer of spleen cell suspensions.

Animals↗

PubMed1992

Analysis of genetic variation of epizootic hemorrhagic disease virus and bluetongue virus field isolates by coelectrophoresis of their double-stranded RNA.

Thirty-two bovine field isolates of bluetongue virus (BTV), 6 field isolates of epizootic hemorrhagic disease virus (EHDV) from deer, 4 BTV prototype serotypes (10, 11, 13, and 17), and 2 EHDV prototype serotypes (1 and 2) were coelectrophoresed, using polyacrylamide gels. Field isolates were obtained from various regions of the United States. Analysis of polyacrylamide gels and scattered plots generated for comparison of migration patterns for different isolates within each serotype of BTV revealed wide variation among the individual segments. The BTV serotypes 10 and 11 had more variation, compared with BTV serotypes 13 and 17, especially for migration of genome segment 5. A definitive correlation was not seen between the double-stranded RNA migration profiles on polyacrylamide gel electrophoresis, geographic origin, herd of origin, or year of collection. One BTV field isolate contained more than 1 electropherotype, with 2 bands at the segment-7 position, and it was further characterized as BTV serotype 11. Segments 2 and 5 of EHDV isolates were more variable in their migration than were the other gene segments. Generally, migration profiles for EHDV double-stranded RNA were more variable, compared with those of BTV isolates. Although a correlation was found between migration profiles and serotype of 2 isolates of EHDV, a study of additional EHDV isolates is required before the diversity of electrophoretic patterns of EHDV can be determined.

Animals↗

PubMed1991

Generation of avian cells resembling osteoclasts from mononuclear phagocytes.

Several lines of indirect evidence suggest that a monocyte family precursor gives rise to the osteoclast, although this hypothesis is controversial. Starting with a uniform population of nonspecific esterase positive, tartrate-sensitive, acid phosphatase-producing, mannose receptor-bearing mononuclear cells, prepared from dispersed marrow of calcium-deprived laying hens by cell density separation and selective cellular adherence, we generated multinucleated cells in vitro. When cultured with devitalized bone, these cells show, by electron microscopy, the characteristic osteoclast morphology in that they are mitochondria-rich, multinucleated, and, most importantly, develop characteristic ruffled membranes at the matrix attachment site. Moreover, as documented by scanning electron microscopy, these cells pit bone slices in a manner identical to freshly isolated osteoclasts. In addition, isoenzymes of acid phosphatase from generated osteoclasts, separated by 7.5% polyacrylamide gel electrophoresis at pH 4, are identical to those of mature osteoclasts in migration pattern and tartrate resistance, although the precursor cells from which the osteoclasts are generated produce an entirely different isoenzyme, which is tartrate-sensitive and migrates less rapidly at pH 4. The fused cells also exhibit a cAMP response to prostaglandin E2. Therefore, osteoclast-like cells can be derived by in vitro culture of a marrow-derived monocyte cell population.

Animals↗

PubMed1990

In vivo migration and tissue localization of highly purified lymphokine-activated killer cells (A-LAK cells) in tumor-bearing rats.

Our laboratory has previously reported that the adoptive transfer of highly purified lymphokine-activated killer cells (adherent-LAK, A-LAK) into Fischer 344 (F344) rats bearing established lung or liver micrometastases effectively reduced the resultant tumor growth more than 90%, leading to significant increases in animal survival (Cancer Res. 49, 1441, 1989). To begin to investigate the mechanism(s) by which A-LAK cells mediate this anti-tumor effect, we studied their migration patterns in F344 rats bearing experimentally induced lung and liver metastases as well as subcutaneous tumors. A-LAK cells which were phenotypically 95 to 100% natural killer cells/large granular lymphocytes were labeled with either 51Chromium or fluorescein diacetate (so as to be visualized microscopically). Intravenous injection of such labeled A-LAK cells did not show significant differences in their tissue distribution patterns in tumor-bearing versus normal rats, even when high levels of exogenous recombinant interleukin-2 (rIL-2) was administered. A-LAK cells first migrated to the lungs and then subsequently migrated to the liver and spleen as early as 2 to 6 hr following iv injection. The kinetics of exit of A-LAK cells from the pulmonary capillary beds was not significantly different in rats bearing 3-day micrometastases or 14-day macrometastases compared to normal rats. Moreover, the presence of metastases in the liver did not alter the extent or kinetics of entry of A-LAK cells into the liver even in the presence of exogenously administered rIL-2. Finally, in rats bearing subcutaneous tumors, no evidence could be obtained that A-LAK cells were selectively localized to the tumor site. Tissue sections of livers from metastases-bearing animals injected with fluorescein diacetate labeled A-LAK cells did not demonstrate significant numbers of A-LAK cells infiltrating tumor nests with or without the administration of exogenous IL-2. These data suggest that A-LAK cells may mediate tumor regression in vivo by direct and indirect mechanisms, possibly through the secretion of cytokines and/or the recruitment of secondary effector cells.

Adenocarcinoma↗

PubMed1989

[Transplantation of embryonic cerebella into adult rat cerebella].

Cerebellar primordia of rat embryos (embryonic days of 14-20) were transplanted into mature cerebella of normal adult rats (Fischer 344). After 1-12 months, animals were sacrificed, and the development of grafts and the interaction between host and graft were examined by light and electron microscopy. Grafts from E14 rat cerebella showed the highest survival rate (85%), which decreased with increasing donor age. In some experiments, the donor tissue developed and differentiated to form folia with the trilaminar organization of the cerebellar cortex. Synaptic connections between neuronal elements in the graft showed basically the normal pattern. Thus, mossy terminals formed synaptic contacts with dendrites of granule cells, and axons of basket cells made synaptic contacts with somata of Purkinje cells. Many spines of Purkinje dendrites were contacted with parallel fibers, while others were surrounded by processes of astroglia. Migration of donor Purkinje and granule cells in the host molecular layer was frequently observed. Some donor granule cells, implanted in the superficial aspect of the host molecular layer, migrated down along processes of Bergmann glia, which resembled the migration pattern of the normal development. Other granule cells attached to neuroglial processes which ensheathed capillary walls. While the migration of granule cells was found to be glial-dependent, the glial role in the migration of Purkinje cells was not clear. Purkinje cells probably migrated into the host molecular layer under favorable conditions where the loss of host Purkinje cells had been occurred to some extent and consequently followed by the increase of free axon endings of parallel fibers and interneurons of the host.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1977

Decay of genetic variability in geographically structured populations.

The ultimate rate and pattern of approach to equilibrium of a diploid, monoecious population subdivided into a finite number of equal, large, panmictic colonies are calculated. The analysis is restricted to a single locus in the absence of selection, and every mutant is assumed to be new to the population. It is supposed that either the time-independent backward migration pattern is symmetric in the sense that the probability that an individual at position x migrated from y equals the probability that one at y migrated from x, or it depends only on displacements and not on initial and final positions. Generations are discrete and nonoverlapping. Asymptotically, the rate of convergence is approximately (I-u)2t[I-(2NT)-1]t, where u, NT, and t denote the mutation rate, total population size, and time in generations, respectively; the transient part of the probability that two homologous genes are the same allele is approximately independent of their spatial separation. Thus, in this respect the population behaves as if it were panmictic.

Genetic Variation↗

PubMed1985

Spatial distribution of immature Culicoides variipennis (Coq.).

Circadian fluctuation in the spatial distribution of immature Culicoides variipennis (Coq.) was studied in Saltville, Virginia, USA during the summer of 1983. Pupae and early instar larvae (1st and 2nd) were localized above the shoreline in the top cm of mud and displayed little migration from this region during the 24 hr sampling period, however, later instar larvae (3rd and 4th) showed marked migration patterns. Most larval movement was horizontal rather than vertical and was confined to the top cm of mud. Late instar larvae moved towards the water during the day but migrated up above shoreline during the night. Seasonal fluctuation in larval spatial distribution was also studied. Larvae appeared to move progressively downward into the mud during the autumn. However, when the site became frozen the majority of larvae occupied a narrow liquid interface between the ice cover and the frozen mud beneath.

Animals↗

PubMedDate not supplied

A spatial analysis of 100 surnames in England and Wales.

Spatial patterns are described and analysed for the 84 most common surnames in England and Wales, as well as 16 others selected for various reasons. At least three-quarters of the surname frequencies show spatial structure and are heterogeneous over the area of study. While they do not exhibit clines extending over the entire area of study, they do divide into four characteristics patterns. Spatial autocorrelation, while significant, is relatively low; similarity in surname frequency does not extend much beyond 100 km. Correlograms could be clustered to yield groups of surfaces denoting partial clines, isolation by distance, and differentiation at far distances. A method for detecting zones of rapid change found 21 such zones, mostly near the periphery of the study area. These boundaries do not indicate barriers to gene flow, but appear to be patterns brought about by historical factors. There are diffusion patterns between areas that differ greatly in surname composition, such as Wales and central England. There is little evidence of long-distance movements involving several surnames. At least three characteristic migration patterns, east-west and north-south diffusion and local dispersal, were found.

England↗

PubMedDate not supplied

Human semen prostaglandins do not affect sperm motility and migration.

Prostaglandin (PG) E2, PGF2 alpha and testosterone (T) concentrations were determined in the seminal plasma of 57 fertility-clinic patients. Results (mean less than SE) were: PGE2, 3.44 +/- 0.38 mu/ml; PGF2 alpha, 138 +/- 0.33 micrograms/ml; T, 429.54 +/- 14.01 pg/ml. The material was divided into 4 groups: normospermic, oligozoospermic, asthenozoospermic and azoospermic. No statistically significant differences were found among the values of the different groups, except for PGE2, which was found to be increased in the asthenozoospermic group. Sperm migration patterns were assessed in each semen sample, using the Kremer capillary tube test and human cervical mucus. Considering each semen sample individually, no correlations whatever were found among sperm count, motility and migration parameters and the respective concentrations of both PGs and T, nor was there a correlation among PGE2, PGF2 alpha, and T values of the same sample.

Dinoprost↗

PubMedDate not supplied

Differentiation of the sibling species Biomphalaria occidentalis and Biomphalaria tenagophila by the electrophoretic patterns of their hemoglobin.

A simple and rapid method for differentiating the sibling species Biomphalaria tenagophila and Biomphalaria occidentalis by agarose gel electrophoresis (AGE) is described. Snail hemolymph is used as the test sample and the red coloration of the hemoglobin fraction permits visualization of the migration patterns without resorting to specific stains. Moreover, hemolymph samples may be obtained without killing the snail, thus permitting its use for other studies or for breeding.

Animals↗

PubMedDate not supplied

Effects of migration on cancer incidence and resources for prevention and treatment in Florida.

Migration adds a complex dimension to the task of those who plan and allocate resources for health care. The authors offer a methodology for estimating the contribution of migration to the incidence of cancer, allow for age- and sex-specific cancer risks, and estimate, by country, the impact of recent migration on the annual incidence of cancer in Florida. Cancer and migration data were used to develop estimates of the number of cancer cases for Florida counties that were attributable to recent migrants. A net gain and loss ratio was calculated for new cancer cases in 1980 resulting from the 1975-80 migration pattern. Florida data was used because that State has one of the highest crude cancer incidence rates in the nation, is one of the most populous States, and has a population growth from migration rather than from natural increase. Preliminary findings on the relationship between cancer health services resources and net cancer rates from migration are discussed. County cancer health services resources had a strong positive relationship to population size, but the impact of migration on cancer incidence was in a curvilinear relationship to population size.

Cancer Care Facilities↗

PubMed1992

Phosphorylation by cAMP-dependent protein kinase inhibits the degradation of tau by calpain.

The effects of cAMP-dependent protein kinase (cAMP-PK) phosphorylation on the degradation of the microtubule-associated protein tau by calpain were studied. Purified bovine brain tau that had been phosphorylated by cAMP-PK had a slower migration pattern on sodium dodecyl sulfate-polyacrylamide gels and a more acidic, less heterogeneous pattern on two-dimensional, nonequilibrium pH gradient electrophoresis (NEPHGE) gels compared with untreated tau. Phosphorylation of tau by cAMP-PK significantly inhibited its proteolysis by calpain compared with untreated tau. To our knowledge this is the first demonstration that phosphorylation of tau by a specific kinase results in increased resistance to hydrolysis by calpain. Tau dephosphorylated by alkaline phosphatase migrated more rapidly on sodium dodecyl sulfate-polyacrylamide gels and also showed an altered two-dimensional NEPHGE pattern. Dephosphorylation of tau had no effect on its susceptibility to calpain proteolysis, indicating that regulation of the susceptibility to calpain hydrolysis is due to the phosphorylation of a specific site(s). These results suggest a role for phosphorylation in regulating the degradation of tau. Abnormal phosphorylation could result in a protease-resistant tau population which may contribute to the formation of paired helical filaments in Alzheimer's disease.

Animals↗