Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Migration patterns”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,027 records · Page 57Linked to original sources
PubMed1997

Molecular population studies of Simulium damnosum s.l. (Diptera: Simuliidae) using a novel interspersed repetitive DNA marker.

Simulium damnosum s.l., the vector of West African onchocerciasis, has been the target of a major insect control initiative for the past 20 years. However, attempts to study the migration patterns of reinvading infective flies into controlled areas have been restricted by the lack of suitable genetic markers. Here, the results of the first population-level study of S. damnosum s.l. using a repetitive DNA marker, pSO11, are presented. Sequence analysis of pSO11 revealed a complex internal pattern of repetition and an open reading frame with 56.8 per cent similarity to a mouse retrotransposon protein. Combined with an interspersed genomic distribution, the internal structure of pSO11 suggested that it represents the 5' half of a transposable element. The genomic diversity of the sequence was analysed using Southern blot analysis of genomic DNA. Data were collected from 475 individuals from the island of Bioko (in Equatorial Guinea), Cameroon, Côte d'Ivoire and Sierra Leone. The results indicate that pSO11 is useful as an indicator of genomic diversity and that the experimental design used here permits comparison of an approximately random sample of chromosomal loci. Making this assumption, estimates of homozygosity based on pSO11 diversity were used to study inter- and intraspecific variability. The results indicate that pSO11 is potentially useful for studying population-level processes in S. damnosum s.l.

Animals↗
PubMed2005

Magnetic resonance tracking of dendritic cells in melanoma patients for monitoring of cellular therapy.

The success of cellular therapies will depend in part on accurate delivery of cells to target organs. In dendritic cell therapy, in particular, delivery and subsequent migration of cells to regional lymph nodes is essential for effective stimulation of the immune system. We show here that in vivo magnetic resonance tracking of magnetically labeled cells is feasible in humans for detecting very low numbers of dendritic cells in conjunction with detailed anatomical information. Autologous dendritic cells were labeled with a clinical superparamagnetic iron oxide formulation or (111)In-oxine and were co-injected intranodally in melanoma patients under ultrasound guidance. In contrast to scintigraphic imaging, magnetic resonance imaging (MRI) allowed assessment of the accuracy of dendritic cell delivery and of inter- and intra-nodal cell migration patterns. MRI cell tracking using iron oxides appears clinically safe and well suited to monitor cellular therapy in humans.

Cell Movement↗
PubMed2003

Radiation-hypersensitive cancer patients do not manifest protein expression abnormalities in components of the nonhomologous end-joining (NHEJ) pathway.

Radiation therapy (RT) is utilised for the treatment of around half of all oncology patients during the course of their illness. Despite great clinical progress in the rational deployment of RT, the underlying molecular basis for its efficacy and toxicity are currently imperfectly understood. In this study, we took a biochemical approach to evaluate the potential role of key ionising radiation repair proteins in the treatment outcomes of patients with severe acute or late RT side effects. Lymphoblastoid cell lines were established from blood samples from 36 radiosensitive cases and a number of controls (the latter had had RT but did not develop significant toxicity). The expression level and migration of key proteins from the nonhomologous end-joining (NHEJ) pathway was evaluated by Western blot analysis on cases and controls. We did not observe any abnormalities in expression level or migration pattern of the following NHEJ proteins in radiosensitive cancer cases: Ku70, Ku80, XRCC4, DNA Ligase IV. These important negative results provide evidence that mutations that affect protein expression of these NHEJ components are unlikely to underlie clinical radiation sensitivity.

Cohort Studies↗
PubMed2004

Normal expression of DNA repair proteins, hMre11, Rad50 and Rad51 but protracted formation of Rad50 containing foci in X-irradiated skin fibroblasts from radiosensitive cancer patients.

About 5% of oncology patients treated by radiation therapy develop acute or late radiotoxic effects whose molecular mechanisms remain poorly understood. In this study, we evaluated the potential role of DNA repair proteins in the hypersensitivity of cancer patients to radiation therapy. The expression levels and focal nuclear distribution of DNA repair proteins, hMre11, Rad50 and Rad51 were investigated in skin fibroblasts strains derived from cancer patients with adverse early skin reaction to radiotherapy using Western blot and foci immunofluorescence techniques, respectively. Cells from cancer patients with normal reaction to radiotherapy as well as cells from apparently healthy subjects served as controls. Cellular radiosensitivity after in vitro irradiation was assessed by the clonogenic survival assay. The clonogenic survival assay and Western blot analysis of the DNA repair proteins did not reveal any abnormalities in cellular radiosensitivity in vitro and in protein expression levels or their migration patterns in the fibroblasts derived from cancer patients with hypersensitive reaction to radiotherapy. In contrast, in vitro irradiated cells from radiosensitive patients exhibited a significantly higher number of nuclei with focally concentrated Rad50 protein than in both control groups. The observed alteration of the distribution of radiation-induced Rad50 foci in cells derived from cancer patients with acute side reactions to radiotherapy might contribute to their radiation therapy outcome. These data suggest the usefulness of the Rad50 foci analysis for predicting clinical response of cancer patients to radiotherapy.

Acid Anhydride Hydrolases↗
PubMed2000

mtDNA hypervariable region II (HVII) sequences in human evolution studies.

Variation in human mitochondrial DNA (mtDNA) has been used to infer the origin and migration patterns in human populations. mtDNA analysis has been focused mainly on the first hypervariable region (HVI). Nevertheless, although many studies of the second hypervariable region (HVII) have been carried out during recent years, the correlation between the first and the second hypervariable regions has not been well established. We have analysed 71 individuals from a relatively isolated region at the westernmost edge of continental Europe (Galicia, NW Iberian peninsula) and we have used available HVII sequence information from another 17 European and African populations. The results show high concordance between the two hypervariable regions, not only in variability levels but also in other phylogenetic aspects. The study of the population structure through an AMOVA analysis shows a low level of heterogeneity in the European populations. Nevertheless, we have found some inconsistency in the results, which are related to the mutation rate in these two hypervariable regions. These results are compatible with a high heterogeneity of mutation rates across the HVII region and stress the interest of HVII in population and forensic genetics.

Base Sequence↗
PubMed2001

Loss of heterozygosity at 4p16.3 and mutation of FGFR3 in transitional cell carcinoma.

4p16.3 has previously been identified as a region of non-random LOH in transitional cell carcinoma, suggesting the presence of a tumour suppressor gene. One candidate within this region is fibroblast growth factor receptor 3 (FGFR3). Germline mutations in FGFR3 are known to cause several autosomal dominant skeletal dysplasias, the severity of which depends on the position and nature of the mutation in the protein. We investigated the frequency and nature of FGFR3 mutations in a panel of transitional cell carcinomas and cell lines and studied the possible link between mutation and loss of heterozygosity (LOH) on 4p16.3. FGFR3 coding sequence from 63 transitional cell carcinomas (TCC) of various stages and grades, and 18 cell lines was analysed by fluorescent SSCP. Samples with abnormal migration patterns were sequenced to identify the mutation or polymorphism. Thirty-one of the 63 tumours had previously been assessed to have LOH at 4p16.3. Twenty-six of the 63 tumours (41%) and 4/18 (22%) of the cell lines had missense mutations in FGFR3. All mutations detected in our panel have been reported in the germline where all apart from one cause lethal conditions. One tumour contained K652Q which has recently been identified in less severe cases of skeletal dysplasia. Tumours with and without LOH at 4p16.3 had mutations in FGFR3 suggesting that these two events are not causally linked. The frequency of FGFR3 mutation indicates that this protein plays an important role in TCC.

Carcinoma, Transitional Cell↗
PubMed1984

Separation of radiolabelled glycosaminoglycan oligosaccharides by polyacrylamide-gel electrophoresis.

Glycosaminoglycan oligosaccharides generated by treatment of biosynthetically radiolabelled dermatan sulphate and hyaluronic acid with chondroitin AC lyase or testicular hyaluronidase may be resolved into a series of discrete bands by polyacrylamide-gel electrophoresis. Bands were identified by fixation in glacial acetic acid containing 20% (w/v) 2,5-diphenyloxazole followed by fluorography. The bands represented glycans which differed in size by one disaccharide unit. For the larger oligosaccharides (decasaccharides and above) of similar charge: mass ratio, there was a linear relationship between electrophoretic mobility and log Mr. However, the smaller species showed anomalous migration patterns. Consideration of the structures of the fragments produced by the different enzyme treatments suggests that copolymeric and homopolymeric oligosaccharides may be separated by polyacrylamide-gel electrophoresis. There are many potential applications of this technique, foremost amongst them being studies on the molecular size heterogeneity and patterns of enzyme-mediated depolymerization of native glycosaminoglycan chains and investigations into rates of polymer chain elongation and post-polymerization modification reactions so essential to glycosaminoglycan function.

Chromatography, Gel↗
PubMed1992

Simultaneous presence of two distinct endoplasmic-reticulum-type calcium-pump isoforms in human cells. Characterization by radio-immunoblotting and inhibition by 2,5-di-(t-butyl)-1,4-benzohydroquinone.

Phosphorylation, immunoblotting, limited proteolysis and drug-sensitivity analysis were used to characterize the sarcoendoplasmic-reticulum Ca2+ ATPases in a variety of human cell types. In platelets, several megakaryoblastoid and lymphoblastoid cell lines two distinct autophosphorylated forms of these ATPases with molecular mass of 100 and 97 kDa could be observed, whereas in several other cell types the 97 kDa form was absent. On immunoblots the 97 kDa species was specifically recognized by an inhibitory monoclonal antibody raised against the Ca2+ pump of platelet internal membranes, yielded on trypsinolysis a major fragment of 80 kDa, exhibited a distinct electrophoretic migration pattern as compared with the skeletal-, cardiac- and smooth-muscle Ca2+ pumps, and its autophosphorylation was strongly inhibited by the Ca(2+)-mobilizing agent 2,5-di-(t-butyl)-1,4-benzohydroquinone (tBHQ). The 100 kDa species reacted with an antibody specific for the cardiac- and smooth-muscle Ca2+ pumps, yielded on trypsinolysis fragments of 55 and 35 kDa, and its autophosphorylation was much less sensitive to tBHQ inhibition. These findings indicate the simultaneous presence of two different endoplasmic-reticulum Ca2+ pumps in a variety of human cell types, and may explain the previously observed differences in the Ca(2+)-handling characteristics of different intracellular Ca2+ pools and cell types.

Antibodies, Monoclonal↗
PubMed2003

Neuron-glia interactions during axon guidance in Drosophila.

Axons navigate to trace stereotypic trajectories over an environment often rich in glial cells. Once axonal trajectories are defined, their structuring proceeds through multiple fasciculation and defasciculation events, to finally establish the mature bundles. Fasciculation and ensheathment also proceed in close association between axons and glial cells, and ultimately require glia. The cross-talk between axons and glia during axon guidance is manifested in: (i) axonal fasciculation and bundling, promoted by glia; (ii) growth cone guidance, as glia function as guidepost cells at choice points; (iii) glial migration patterns, which are influenced by neurons; (iv) cell survival control, which constrains position and number of both cell types; and (iv) connectivity, where an axon contacts its final target aided by glial cells. Understanding the reciprocal interactions between neurons and glia during guidance and fasciculation is absolutely necessary to implement repair of axonal trajectories upon damage. Drosophila can be used as a model system for these purposes.

Animals↗
PubMed1997

Differential titin isoform expression in human skeletal muscle.

Mammalian skeletal muscle expresses at least two isoforms of the cytoskeletal protein titin (connectin; MW approximately 3000 kDa). These isoforms are associated with different passive force curves, and thus may affect physical performance. To study the distribution of titin and its possible influence on performance in humans, muscle biopsies were obtained from 15 males (mean +/- SE; age = 25.4 +/- 2.9 years, height = 177.7 +/- 1.8 cm, weight = 76.5 +/- 2.2 kg). Two biopsies were obtained on separate occasions from both the right and left vastus lateralis, and one biopsy each from the lateral head of the right gastrocnemius and the right soleus, with all biopsies handled identically. Fibre type analyses were performed via mATPase histochemistry. Expression of titin and myosin heavy chain isoforms were determined by SDS-PAGE. Titin bands in the resulting gels were highly repeatable and were verified by migration patterns, as well as Western blot analysis. Two groups of subjects were identified: group 1 (n = 10) expressed only one titin isoform (titin-1) in all biopsies, and group 2 (n = 5) expressed two titin isoforms (titin-1 and titin-2) in all biopsies. No significant differences (P > 0.05) between groups were observed for percentage fibre types, percentage fibre type areas, fibre type cross-sectional areas, and percentage myosin heavy chain expression when comparing individual muscles, sampling times or bilateral comparisons. This is the first report of differential titin isoform expression in healthy, mature human skeletal muscle, but it is not clear why this occurs or what influence this may have on performance.

Adult↗
PubMed1996

Molecular characterization of haemophilia A in southern Chinese.

41 unrelated southern Chinese haemophilia A patients were studied. The 5' promoter region, all 26 exons, their immediate 5' and 3' flanking splice junctions and the 3' untranslated region of the FVIII gene were amplified (including 16 different segments of exon 14) using GC-clamped primers. The GC-clamped PCR products were screened by denaturing gradient gel electrophoresis (DGGE) and fragments showing an abnormal migration pattern were sequenced. 17 mutations were identified, of which four were splicing defects, involving the first 1-6 nucleotide (nt) in the intervening sequences (IVS), six missense mutations, three nonsense mutations and four frameshift mutations. 14 other patients carried the type 1 inversion, affecting the distal copy of the FSA gene at the telomere of the X chromosome and the same gene in intron 22 of the FVIII gene. All the mothers studied (12/14) were carriers of the inversion. Two of these patients with inversion also have a co-existing missense mutation. In most cases the clinical severity of the disease corresponds to the genotype.

Base Sequence↗
PubMed1999

A novel mutation of delta-aminolaevulinate dehydratase in a healthy child with 12% erythrocyte enzyme activity.

Cloning, expression and phenotype studies of the defective gene for delta-aminolaevulinate dehydratase (ALAD) in a family with an asymptomatic girl who had ALAD deficiency were carried out. The proband was identified by neonatal ALAD screening, and had erythrocyte ALAD activity at 12% of the normal control. She was heterozygous for ALAD deficiency, which was inherited from her father. Nucleotide sequence analysis of the cloned ALAD cDNA revealed C36 to G and T168 to C mutations on the same allele. The former mutation resulted in F12L substitution, whereas the latter was a silent mutation. All family members who had decreased ALAD activity had the same mutation. Expression of the mutant ALAD cDNA in Chinese hamster ovary cells produced an ALAD protein without significant enzyme activity. Additionally, the mutant ALAD cDNA which encodes F12L substitution produced an aberrant migration pattern in polyacrylamide gel electrophoresis under denaturing conditions. This finding probably reflects an abnormal folding of the F12L protein, since the mutation occurred in the alpha1 helix of the N-terminal arm of the enzyme, which is involved in the extensive quaternary interactions among the subunits. This is also the first report of ALAD gene mutation in an asymptomatic subject.

DNA, Complementary↗
PubMed1997

Mutation screening of interferon-gamma (IFNgamma) as a candidate gene for asthma.

BACKGROUND: Reduced levels of interferon gamma (IFNgamma) mRNA and protein have been detected in the bronchoalveolar lavage fluid of atopic asthmatics. IFNgamma is secreted by TH1 cells while IL-4 and IL-5 are secreted by TH2 cells and an imbalance in the TH1/TH2 response may be responsible for atopic asthma. The gene for IFNgamma is located on chromosome 12; a region of the genome which has been shown in linkage studies to be associated with asthma. OBJECTIVE: To determine if there are any mutations present in the coding exons and 5' flanking region of the IFNgamma gene in atopic asthmatic subjects compared with controls to explain the lower levels of this cytokine as an inherited, rather than acquired, factor in the asthmatic subjects. METHODS: The four exons and 5' flanking region of the IFNgamma gene were amplified by polymerase chain reaction (PCR) from genomic DNA of 265 individuals from a Western Australian and a Venezuelan population. The PCR products were examined by single strand conformational polymorphism and heteroduplex analyses to see if there were any changes in the DNA migration patterns which would suggest the presence of a sequence variation. RESULTS: The four exons and the 5' flanking region of the IFNgamma gene were amplified from 265 individuals from two populations. Single strand conformational polymorphism and heteroduplex analyses did not reveal any mutations in the regions examined. CONCLUSION: The gene for IFNgamma appears to be highly conserved as no sequence variations were detected in 265 individuals. These results suggest that mutations of the IFNgamma gene are unlikely to be a significant cause of an inherited asthma diathesis.

Adolescent↗
PubMed2003

Postglacial population growth of Cunninghamia konishii (Cupressaceae) inferred from phylogeographical and mismatch analysis of chloroplast DNA variation.

Phylogeographical and mismatch analysis of chloroplast DNA (cpDNA) variation were used to infer the temporal dynamics of distributional and demographic history of Taiwan fir (Cunninghamia konishii). We examined 64 and 52 trees from 17 populations of C. konishii and 14 provenances of C. lanceolata, respectively, by sequencing three intergenic spacers and one intron using cpDNA universal primers. Of the aligned 1888 base pairs (bp) sequence, 30 varied among 28 haplotypes, which consisted of three transitions, 14 transversions and 13 indels. One ancestral haplotype was found in 86 individuals across the surveyed range of both species, C. konishii and C. lanceolata, which was distributed in all populations and provenances. The 28 haplotypes also included 15 C. konishii specific and 12 C. lanceolata-specific haplotypes. Ancestral haplotype was found fixed in five populations of C. konishii and five provenances of C. lanceolata. Other haplotypes occurred mainly as singletons. The levels of population differentiation studied are relatively low in both Cunninghamia species. The nucleotide diversity (theta) of chloroplast DNA sequences within C. konishii was slightly higher than that of C. lanceolata. Excess in singletons as well as star-like phylogeny of haplotypes suggested no clearcut migration patterns of C. konishii after glacial maximum. One probable demographic history of C. konishii is the postglacial population growth of C. konishii after a glacial bottleneck event. This inference is supported by the combined results of fossil pollen record, low nucleotide diversity, significant Tajima's d-value, phylogeographical analysis and unimodal mismatch distribution. Similarities and discrepancies between our results and those of Lu et al. (2001) are discussed.

Climate↗
PubMed1997

Membrane cofactor protein (MCP or CD46) is a cellular pilus receptor for pathogenic Neisseria.

Pili of Neisseria gonorrhoeae and Neisseria meningitidis mediate binding of the bacteria to human cell-surface receptors. We found that purified pili bound to a 55- to 60-kDa doublet band on SDS-PAGE of separated human epithelial cell extracts. This is a migration pattern typical of membrane cofactor protein (MCP or CD46). MCP is a widely distributed human complement regulatory protein. Attachment of the bacteria to epithelial cells was blocked by polyclonal and monoclonal antibodies directed against MCP, suggesting that this complement regulator is a receptor for piliated Neisseria. We proved this hypothesis by demonstrating that piliated, but not non-piliated, gonococci bound to CHO cells transfected with human MCP-cDNA. We also demonstrated a direct interaction between purified recombinant MCP and piliated Neisseria. Finally, recombinant MCP protein produced in E. coli inhibited attachment of the bacteria to target cells. Taken together, our data show that MCP is a human cell-surface receptor for piliated pathogenic Neisseria.

Animals↗
PubMed2003

The identification of circular extrachromosomal DNA in the nuclear genome of Trypanosoma brucei.

Nuclear extrachromosomal DNA elements have been identified in several kinetoplastids such as Leishmania and Trypanosoma cruzi, but never in Trypanosoma brucei. They can occur naturally or arise spontaneously as the result of sublethal drug exposure of parasites. In most cases, they are represented as circular elements and are mitotically unstable. In this study we describe the presence of circular DNA in the nucleus of Trypanosoma brucei. This novel type of DNA was termed NR-element (NlaIII repeat element). In contrast to drug-induced episomes in other kinetoplastids, the T. brucei extrachromosomal NR-element is not generated by drug selection. Furthermore, the element is stable during mitosis over many generations. Restriction analysis of tagged NR-element DNA, unusual migration patterns during pulsed field gel electrophoresis (PFGE) and CsCl/ethidium bromide equilibrium centrifugation demonstrates that the NR-element represents circular DNA. Whereas it has been found in all field isolates of the parasites we analysed, it is not detectable in some laboratory strains notably the genome reference strain 927. The DNA sequence of this element is related to a 29 bp repeat present in the subtelomeric region of VSG-bearing chromosomes of T. brucei. It has been suggested that this subtelomeric region is part of a transition zone on chromosomes separating the relatively stable telomeric repeats from the recombinationaly active region downstream of VSG genes. Therefore, we discuss a functional connection between the occurrence of this circular DNA and subtelomeric recombination events in T. brucei.

Animals↗
PubMed2002

A systematic review of current knowledge of HIV epidemiology and of sexual behaviour in Nepal.

OBJECTIVE: To systematically review information on HIV epidemiology and on sexual behaviour in Nepal with a view to identifying gaps in current knowledge. METHODS: Systematic review covering electronic databases, web-based information, personal contact with experts and hand searching of key journals. RESULTS: HIV-1 seroprevalence has been rising rapidly in association with high-risk behaviours, with current levels of 40% amongst the nation's injecting drug users and approaching 20% amongst Kathmandu's female commercial sex workers (FCSWs). HIV seroprevalence remains low in the general population (0.29% of 15-49 year olds). There are significant methodological limitations in many of the seroprevalence studies identified, and these estimates need to be treated with caution. There are extensive migration patterns both within the country and internationally which provide the potential for considerable sexual networking. However, studies of sexual behaviour have focused on FCSWs and the extent of sexual networks within the general population is largely unknown. CONCLUSIONS: Whilst some of the ingredients are present for an explosive HIV epidemic in Nepal, crucial knowledge on sexual behaviour in the general population is missing. Research on sexual networking is urgently required to guide HIV control in Nepal. There is also a need for further good-quality epidemiological studies of HIV seroprevalence.

Adolescent↗
PubMed2001

Migration of Langerhans cells and gammadelta dendritic cells from UV-B-irradiated sheep skin.

Depletion of dendritic cells from UV-B-irradiated sheep skin was investigated by monitoring migration of these cells towards regional lymph nodes. By creating and cannulating pseudoafferent lymphatic vessels draining a defined region of skin, migrating cells were collected and enumerated throughout the response to UV-B irradiation. In the present study, the effects of exposing sheep flank skin to UV-B radiation clearly demonstrated a dose-dependent increase in the migration of Langerhans cells (LC) from the UV-B-exposed area to the draining lymph node. The range of UV-B doses assessed in this study included 2.7 kJ/m2, a suberythemal dose; 8 kJ/m2, 1 minimal erythemal dose (MED); 20.1 kJ/m2; 40.2 kJ/m2; and 80.4 kJ/m2, 10 MED. The LC were the cells most sensitive to UV-B treatment, with exposure to 8 kJ/m2 or greater reproducibly causing a significant increase in migration. Migration of gammadelta+ dendritic cells (gammadelta+ DC) from irradiated skin was also triggered by exposure to UV-B radiation, but dose dependency was not evident within the range of UV-B doses examined. This, in conjunction with the lack of any consistent correlation between either the timing or magnitude of migration peaks of these two cell types, suggests that different mechanisms govern the egress of LC and gammadelta+ DC from the skin. It is concluded that the depression of normal immune function in the skin after exposure to erythemal doses of UV-B radiation is associated with changes in the migration patterns of epidermal dendritic cells to local lymph nodes.

Animals↗