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At least 307 records · Page 17Linked to original sources
PubMed1996

Analysis of Epstein-Barr virus (EBV) type and variant in spontaneous lymphoblastoid cells and Hu-SCID mouse tumours.

Epstein-Barr virus (EBV) type and strain variations were examined using both lymphoblastoid cell lines (LCLs), spontaneously derived in vitro from peripheral blood mononuclear cells (PBMC) of 15 HIV-1-seropositive individuals; and SCID mouse tumours induced by inoculation of PBMC from 11 healthy human donors (Hu-SCID tumours). Polymerase chain reaction (PCR) analysis disclosed that all but one of the 26 EBV + samples harboured EBV nuclear antigen (EBNA) 2 and 3C type A virus. On the other hand, single strand conformation polymorphism (SSCP) analysis using Epstein-Barr encoded RNA (EBER) specific primers detected an AG876-like (type B) band pattern in 21 of the 26 EBV + samples. Three Hu-SCID tumours scored as B95.8-like (type A), and two showed neither a type A nor a type B SSCP migration pattern. Sequence analysis of the amplified EBER fragments confirmed the PCR-SSCP findings; moreover, additional mutations were present not only in the two EBV + samples with anomalous SSCP pattern, but also in two other samples with a standard SSCP profile. Thus, EBER analysis did not correlate with EBNA typing, and appeared to be unsuitable for EBV type assessment. Latent membrane protein (LMP) analysis disclosed, on the whole, sever size variants: as expected, the differences were due to the variable numbers of a 33-bp repeat in the amplified fragment, as assessed by direct sequencing. The broader variability detected by LMP analysis should prove more useful than typing for assessing the presence of single and/or mixed variants resulting from EBV reactivation and/or reinfection.

Animals↗
PubMed1996

branchless encodes a Drosophila FGF homolog that controls tracheal cell migration and the pattern of branching.

The molecular basis for patterning of complex organ structures like the lung and insect tracheal system is unknown. Here, we describe the Drosophila gene branchless (bnl) and demonstrate that it is a key determinant of the tracheal branching pattern. bnl is required for tracheal branching and is expressed dynamically in clusters of cells surrounding the developing tracheal system at each position where a new branch will form and grow out. Localized misexpression of bnl can direct branch formation and outgrowth to new positions. Generalized misexpression activates later programs of tracheal gene expression and branching, resulting in massive networks of branches. bnl encodes a homolog of mammalian fibroblast growth factors (FGFs) and appears to function as a ligand for the breathless receptor tyrosine kinase, an FGF receptor homolog expressed on developing tracheal cells. The results suggest that this FGF pathway specifies the tracheal branching pattern by guiding tracheal cell migration during primary branch formation and then activating later programs of finer branching at the ends of growing primary branches.

Animals↗
PubMed1995

Migration pathways of CD4 T cell subsets in vivo: the CD45RC- subset enters the thymus via alpha 4 integrin-VCAM-1 interaction.

The present investigation examines the localization and migration of purified T cell subsets in comparison with B cells, CD8 T cells and CD4+ CD8- single-positive thymocytes. CD4 T cell subsets in the rat are defined by mAb MRC OX22 (anti-CD45RC), which distinguishes resting CD4 T cells (CD45RC+) from those (CD45RC-) which have encountered antigen in the recent past--subpopulations often referred to as 'naive' and 'memory'. Purified, 51Cr-labelled CD45RC+ CD4 T cells broadly reflected the migration pattern of CD8 T cells and B cells. Early localization to the spleen was followed by a redistribution to mesenteric lymph nodes (MLN) and cervical lymph nodes (CLN), B cells migrating at a slightly slower tempo. There was almost no localization of these subpopulations to the small or large intestine [Peyer's patches (PP) excluded]. In contrast, CD45RC- CD4 T cells (indistinguishable in size from the CD45RC+ subset) localized in large numbers to the intestine; they were present here at the earliest time point (0.5 h), persisted for at least 48 h but did not accumulate, indicating a rapid exit. Numerically, localization of CD45RC- CD4 T cells in the MLN could be accounted for entirely by afferent drainage from the intestine. Unexpectedly, CD45RC- CD4 T cells (but not other subsets) localized and accumulated in the thymus. In vivo treatment with mAb HP2/1 against the integrin alpha 4 subunit inhibited almost entirely CD45RC- CD4 T cell migration into the PP (98.1%), intestine (87.1%), MLN (89.1%) and thymus (93.5%); migration into the CLN was only reduced by half. To distinguish between recognition of MAdCAM-1 and VCAM-1 by alpha 4-containing integrins, recipients were treated with mAb 5F10 against rat VCAM-1. Except for the thymus and a small reduction in CLN, localization of CD45RC- CD4 T cells was unaffected; entry to the thymus was almost completely blocked (92.3%) by anti-VCAM-1. The results indicated (i) that CD45RC- CD4 T cells alone showed enhanced localization to the gut and PP, probably via alpha 4 beta 7-MAdCAM-1 interaction; (ii) that many CD45RC- cells entered non-mucosal LN independently of alpha 4 integrin or VCAM-1; and (iii) that entry of mature recirculating CD45RC- CD4 T cells into the thymus across thymic endothelium was apparently regulated by alpha 4 integrin-VCAM-1 interaction.

Animals↗
PubMed1994

Anthropometric variation and population structure of the island of Pag, Croatia.

Anthropometric variation in the population of the island of Pag (eastern Adriatic, Croatia) was investigated by using data on 14 head and 24 body dimensions. The data were related to past and present migration patterns, geography, and linguistics. The analyses revealed heterogeneity among three population groups inhabiting geographically defined regions of the island and heterogeneity among the village populations. The congruence between anthropometric variation, migration history, geographic distances, and current linguistic features says much for the strength of the isolating factors on this ecologically uniform island, which have effected the genetic structure of the population.

Adult↗
PubMed1993

Clonal patterns of cell proliferation, migration, and dispersal in the brainstem of the chicken embryo.

Retroviral-mediated gene transfer was used to study clonal patterns of proliferation, migration, and dispersal in the brainstem of the chicken embryo. Clones were generated at stages 13-17 (Hamburger and Hamilton, 1951), a period of neurogenesis in the brainstem neural tube subsequent to the formation of rhombomeres. Clones were examined in separate experiments at stages 24-27, when many neurons migrate and differentiate; at stages 28-29, when brainstem nuclei begin to form; and at stages 34-35, when brainstem nuclei are fully formed. Stages 24-29 are characterized by a general variability in proliferative kinetics and migratory behavior. Clone sizes range from 1 to 29 cells, and migration patterns range from strictly radial (i.e., normal to the ventricular surface) to combined radial and tangential (i.e., perpendicular to the radial component). There is, however, an underlying systematic variation: (1) clones exhibiting tangential migration contain on average more cells than clones exhibiting only radial migration, and (2) the proportion of tangentially migrating clones increases from medial to lateral. By stages 34-35 some individual clones have apparently dispersed to disparate neuronal groups. The regional diversity observed among clones suggests that position along the mediolateral axis may determine the proliferative potential of progenitors and the migratory behavior and subsequent dispersal of their descendants.

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↗
PubMed1994

Geographical variation in a quantitative character.

A model for the evolution of the local averages of a quantitative character under migration, selection, and random genetic drift in a subdivided population is formulated and investigated. Generations are discrete and nonoverlapping; the monoecious, diploid population mates at random in each deme. All three evolutionary forces are weak, but the migration pattern and the local population numbers are otherwise arbitrary. The character is determined by purely additive gene action and a stochastically independent environment; its distribution is Gaussian with a constant variance; and it is under Gaussian stabilizing selection with the same parameters in every deme. Linkage disequilibrium is neglected. Most of the results concern the covariances of the local averages. For a finite number of demes, explicit formulas are derived for (i) the asymptotic rate and pattern of convergence to equilibrium, (ii) the variance of a suitably weighted average of the local averages, and (iii) the equilibrium covariances when selection and random drift are much weaker than migration. Essentially complete analyses of equilibrium and convergence are presented for random outbreeding and site homing, the Levene and island models, the circular habitat and the unbounded linear stepping-stone model in the diffusion approximation, and the exact unbounded stepping-stone model in one and two dimensions.

Biological Evolution↗
PubMed2001

Retention of CXCR4 in the endoplasmic reticulum blocks dissemination of a T cell hybridoma.

The dissemination of T cell hybridomas to multiple nonhematopoietic tissues is blocked by pertussis toxin, suggesting the involvement of a chemokine. To study whether this chemokine is SDF-1, we employed a strategy proposed previously for gene therapy of AIDS, whereby the SDF-1 receptor CXCR4 (also a coreceptor for HIV) is retained in the endoplasmic reticulum (ER) and fails to reach the cell surface. We transfected SDF-1, carrying an ER retention sequence, into a T cell hybridoma. This altered chemokine is retained in the ER, where it binds CXCR4 and prevents the latter protein from reaching the surface. These cells failed to migrate toward SDF-1 or to invade fibroblast monolayers, although they could still migrate toward thymus and activation-regulated chemokine (TARC) and invade TARC-treated monolayers. Furthermore, the ability of the transfected cells to disseminate to multiple organs upon intravenous injection into mice was abolished. This dissemination reflects the in vivo migration patterns of activated and memory T cells into nonhematopoietic tissues, which is thus likely to depend on CXCR4. Attempts to block CXCR4 function as a therapy for AIDS may affect this migration with consequences for T cell function. Our results also suggest a decisive role for CXCR4 in the dissemination of hematopoietic malignancies expressing this receptor.

Animals↗
PubMed1995

The role of Hoxa-3 in mouse thymus and thyroid development.

Targeted disruption of Hoxa-3 results in a number of regionally restricted defects in tissues and structures derived from or patterned by mesenchymal neural crest. However, analysis of mutant embryos with injections of a carbocyanine dye or with molecular markers that label these cells indicates that neither the amount nor the migration patterns of this neural crest population are grossly affected. Therefore, it appears that the loss of Hoxa-3 affects the intrinsic capacity of this neural crest cell population to differentiate and/or to induce proper differentiation of the surrounding pharyngeal arch and pouch tissues. Hoxa-3 mutant mice are athymic and show thyroid hypoplasia. Thymus development is first evident as an expansion of mesenchymal neural crest in the posterior part of the 3rd pharyngeal pouch. Prior to this expansion, a marked reduction in pax-1 expression is observed in these cells in the mutant embryos. As pax-1 mutant mice also show thymic hypoplasia, these results suggest that Hoxa-3 may be required to maintain pax-1 expression in these cells and that the reduction of pax-1 expression is part of the athymic teleology in Hoxa-3 mutant mice. The thyroid gland is formed from the fusion of two structures of separate embryonic origin, the thyroid diverticulum, which is formed from endodermal epithelium in the floor of the pharynx, and the ultimobranchial body, formed from mesenchymal neural crest in the 4th pharyngeal pouch. Both of these sites express Hoxa-3 and are defective in mutant mice. Often a vesicle is observed in mutant mice that is exclusively composed of calcitonin-producing cells, suggesting the persistence of an ultimobranchial body. Both aspects of the thyroid phenotype show variable expressivity among mutant animals, even on the two sides of the same mutant animal. This variability suggests the presence of a compensating gene or genes, whose utilization is stochastic. A reasonable candidate for providing this compensatory function is the paralogous gene Hoxb-3.

Animals↗
PubMed1980

Migration of the acetabular socket after total hip replacement determined by roentgen stereophotogrammetry.

UNLABELLED: In order to evaluate the feasibility of a roentgen stereophotogrammetric method for the analysis of the migration pattern of joint prostheses, tantalum balls were implanted into the acetabular socket and the pelvic bone during total hip replacement in four patients with rheumatoid arthritis. During the postoperative period, the migration of the acetabular socket was determined. The observation period varied from 5-24 months. No clinical or radiographic signs of mechanical loosening or infection were noted. All the investigated patients showed a gradual migration of the acetabular socket. The cranial migration measured up to 1.8 mm in 2 years. The migration along the transverse and sagittal axes was less but not constantly directed. The rotatory movements about the three axes varied and measured up to 5.5 degrees in 2 years. The translation and rotation were greatest during the first few months. The results indicate a gradual migration of the acetabular socket in hip arthroplasty in the osteopenic skeleton in rheumatoid arthritis. IN CONCLUSION: roentgen stereophotogrammetry may prove to be a valuable means of analysing the migration of implanted prostheses and detecting prosthetic loosening, thereby increasing the possibility of early and correct diagnosis and therapy.

Acetabulum↗
PubMed1984

Fasting canine biliary secretion and the sphincter of Oddi.

This study correlates duodenal bile acid delivery with motility of the sphincter of Oddi during the fasting state. Dogs were prepared with a functional cholecystectomy, a duodenal cannula for direct vision cannulation of the common bile duct, and 12 bipolar electrodes serosally implanted from stomach to terminal ileum. In one set of experiments, the bile acid pool was depleted, and during a continuous i.v. infusion of sodium taurocholate (20 mumol/min), duodenal bile acid delivery was assessed over 6 h by a marker perfusion technique. In other experiments, a double-lumen continuously perfused manometry catheter was placed to record motility in the bile duct and sphincter of Oddi for a period of 6 h. Station pull-throughs of the sphincter of Oddi were performed in each phase of the migrating motor complex. Bile acid secretion rates fluctuated about the i.v. infusion rate during duodenal phase I and II, peaked in late phase II, and then fell to barely detectable levels during duodenal phase III. There was no peristaltic contractile activity in the common bile duct in any phase of the migrating motor complex. The sphincter of Oddi maintained a baseline pressure above common bile duct pressure. It was highest during phase III. Phasic contractions of the sphincter of Oddi were intermittent during phase I, increasingly frequent during phase II, and continuous during duodenal phase III of the migrating motor complex. Contractions were frequently peristaltic. We concluded that the occurrence and amplitude of phasic peristaltic contractions of the sphincter of Oddi are cyclically coordinated with the fasting intestinal motor pattern (migrating motor complex), and with cyclical variations in the delivery of bile acids into the duodenum. Both resting pressure and phasic contractions of the sphincter appear to play a role in coordinating the cyclic delivery of bile acids into the duodenum with the migrating motor complex. Intense phasic motor activity appears to impede bile flow, and less intense activity allows or facilitates flow.

Action Potentials↗
PubMed1996

Murine p53 is phosphorylated within the PAb421 epitope by protein kinase C in vitro, but not in vivo, even after stimulation with the phorbol ester o-tetradecanoylphorbol 13-acetate.

The p53 tumour suppressor protein is thought to play a major role in the defence of the cell against agents which damage DNA. p53 is phosphorylated at multiple sites in vivo and by several different protein kinases in vitro. In this report, we have examined the phosphorylation of murine p53 by protein kinase C (PKC). Phosphopeptide mapping, phosphoamino acid analysis and radiosequence analysis of p53 phosphorylated by PKC in vitro indicated that serine 370 and threonine 377 were the major targets for phosphorylation and suggested that serine 372 and threonines 365 and 371 were minor phosphorylation sites. Site-directed mutagenesis confirmed that residues 370-372, all of which lie within the epitope for monoclonal antibody PAb421, were phosphorylated in vitro. The p53 from 32P-labelled SV3T3 cells showed a phosphopeptide pattern which includes peptides with mobilities similar to those arising from phosphorylation of residues 370-372 by PKC in vitro. Only two of these in vivo-labelled phosphopeptides co-migrated in two dimensions with peptides labelled in vitro within the PAb421 epitope and their phosphorylation was not stimulated by the addition of the PKC activator o-tetradecanoylphorbol 13-acetate (TPA) to the cells, even though this treatment led to a fourfold stimulation of p53 phosphorylation by MAP kinase. Moreover, when the p53 proteins containing mutations at residues 370-372 were expressed in COS cells, there was no loss of any of the in vivo phosphopeptides, indicating that phosphorylation within the PAb42I epitope was undetectable in the cell. These data suggest that p53 and PKC may not interact in vivo. The two-dimensional migration pattern of the novel group of peptides is consistent with phosphorylation of previously uncharacterised sites within the central DNA binding region of p53.

3T3 Cells↗
PubMed1997

Sporadic phaeochromocytomas are rarely associated with germline mutations in the von Hippel-Lindau and RET genes.

OBJECTIVE: von Hippel-Lindau (VHL) disease and multiple endocrine neoplasia type 2 (MEN2) are autosomal dominant cancer syndromes. In both conditions, phaeochromocytoma is a prominent feature. It has recently been suggested that phaeochromocytoma can be the presenting and sole clinical manifestation of these multi-organ syndromes. The aim of this study was to ascertain the incidence of VHL and MEN2 among patients with sporadic phaeochromocytoma by mutational analysis. PATIENTS: Twenty-seven unrelated patients with biochemically and/or anatomically proven sporadic phaeochromocytoma were evaluated. DESIGN AND MEASUREMENTS: Constitutional DNA obtained from the patients was analysed by single stranded conformational analysis (SSCP) for mutations within the VHL gene coding sequence and by denaturing gradient gel electrophoresis (DGGE) for predominant mutations in exons 10, 11 and 16 of the RET proto-oncogene. The incidence of patients positive for either VHL or RET germline mutations was assessed. RESULTS: Twenty-six of 27 patients had normal SSCP patterns in all three VHL gene exon segments and only one patient, with an atypical clinical presentation, had an aberrant pattern in exon 3 which upon DNA sequencing was shown to harbor a G to A transversion mutation at nucleotide 695. All patients had normal RET exon 10, 11 and 16 DGGE migration patterns. CONCLUSION: Most, if not all, patients with typical unilateral sporadic phaeochromocytoma do not have von Hippel-Lindau disease or MEN2. Thus, clinical and/or molecular investigation for von Hippel-Lindau disease and MEN2 in this patient population does not appear to be indicated.

Adolescent↗
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↗
PubMedDate not supplied

Isoforms of heavy and light chains of cardiac myosins from rat and rabbit.

The light chains of myosin from atrial and ventricular tissues from rat and rabbit were examined by one- and two-dimensional polyacrylamide gel electrophoresis. The myosin heavy chains were electrophoretically isolated, digested after denaturation in sodium dodecyl sulfate with papain and proteinase from S. aureus V8, and the resulting peptides resolved in one-dimensional gel electrophoresis. The peptide patterns of myosin heavy chains from atrial and ventricular tissues of adult rabbits were different, indicating differences in their primary structures. No such differences could be detected in a total of around 180 peptides produced by the two proteinases from the myosin heavy chains of adult rat atrial and ventricular tissues. With regard to light chains, the same migration pattern was observed for atrial and ventricular tissues from both rat and rabbit. The atrial light chains ALC1 and ALC2 migrated with molecular weights lying between those of the ventricular light chains VLC1 and VLC2. In two-dimensional electrophoresis, the corresponding light chains from rat and rabbit co-migrated. An additional light chain was observed in foetal ventricles, which exhibited identical electrophoretic properties to ALC1 from adult atrial tissues. In rat myofibrillar preparations from atrium and ventricle, an unidentified protein (x) occurred in the region of light chain-1 but with a more acidic isoelectric point, which seems to be related to the developmental stage of these tissues and which could not be detected in rabbit heart tissues or in any skeletal muscles.

Animals↗
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↗