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C J Edgell

Publications and source records attributed to C J Edgell.

28 records · Page 2Linked to original sources

Prostacyclin expression by a continuous human cell line derived from vascular endothelium.

Prostacyclin is primarily an endothelial cell product. It contributes to the important role of endothelium in maintaining the fluidity of blood by inhibiting platelet aggregation and by promoting vasodilation. Endothelial cells in culture tend to senesce, and the level of prostacyclin expression decreases. A permanent human cell line, EA.hy 926, derived from a fusion of primary endothelial cells with cells of a less differentiated line, has been found to sustain basal and stimulated levels of prostacyclin synthesis.

6-Ketoprostaglandin F1 alpha↗

Characterization of human blood coagulation factor XII cDNA. Prediction of the primary structure of factor XII and the tertiary structure of beta-factor XIIa.

A human liver cDNA library was screened by colony hybridization with two mixtures of synthetic oligodeoxyribonucleotides as probes. These oligonucleotides encoded regions of beta-factor XIIa as predicted from the amino acid sequence. Four positive clones were isolated that contained DNA coding for most of factor XII mRNA. DNA sequence analysis of these overlapping clones showed that they contained DNA coding for part of an amino-terminal extension, the complete amino acid sequence of plasma factor XII, a TGA stop codon, a 3' untranslated region of 150 nucleotides, and a poly(A)+ tail. The cDNA sequence predicts that plasma factor XII consists of 596 amino acid residues. Within the predicted amino acid sequence of factor XII, we have identified three peptide bonds that are cleaved by kallikrein during the formation of beta-factor XIIa. Comparison of the structure of factor XII with other proteins revealed extensive sequence identity with regions of tissue-type plasminogen activator (the epidermal growth factor-like region and the kringle region) and fibronectin (type I and type II homologies). As the type II region of fibronectin contains a collagen-binding site, the homologous region in factor XII may be responsible for the binding of factor XII to collagen. The carboxyl-terminal region of factor XII shares considerable amino acid sequence homology with other serine proteases including trypsin and many clotting factors. A preliminary structural model of beta-factor XIIa is proposed based on the known high resolution x-ray diffraction structures of trypsin, chymotrypsin, and elastase.

Amino Acid Sequence↗

Coagulation factor XIII: a useful polymorphic genetic marker.

The plasmas of two groups of subjects were examined for blood coagulation Factor XIII-A (FXIII-A, F13A) by electrophoresis in agarose using a Tris-EDTA-borate buffer to separate the common variants, F13A*1, F13A*2, and F13A*3. Dimeric subunits were visualized in UV light as monodansyl cadaverine bound to casein at the position of the transglutaminase activity representing F13A. One test group consisted of 307 members of three large Caucasian families. The other consisted of 148 consecutive patients whose plasmas had been sent to the clinical laboratory for determination of prothrombin time. Segregation analysis and father-to-son transmission confirmed that F13A is inherited as an autosomal co-dominant trait. The allelic frequencies in the random sample were F13A*1 = 0.82 and F13A*2 = 0.18. This sample included both blacks and whites, and the gene frequencies were not significantly different in the two races. The gene frequencies among the unrelated spouses of the three white families were A*1 = 0.75, A*2 = 0.24, A*3 = 0.01. Genetic equilibrium was present in both groups. The degree of polymorphism, the availability of blood, the ease of assessment, the absence of selective pressure, and the uniformity of gene frequencies in two major American ethnic groups make F13A a very useful marker for linkage studies and paternity testing. F13A has been provisionally assigned to chromosome 6. Linkage analysis of our family data did not provide evidence of linkage to two chromosome 6 markers, properdin factor B (BF) and glyoxalase 1 (GLO). The highest lod score (Z) was between F13A and the Kidd (Jk) blood group (theta = 0.68 at = 0.24).

Alleles↗

Permanent cell line expressing human factor VIII-related antigen established by hybridization.

A permanent human cell line, EA . hy 926, has been established that expresses at least one highly differentiated function of vascular endothelium, factor VIII-related antigen. This line was derived by fusing human umbilical vein endothelial cells with the permanent human cell line A549. Hybrid cells that survived in selective medium had more chromosomes than either progenitor cell type and included a marker chromosome from the A549 line. Factor VIII-related antigen can be identified intracellularly in the hybrids by immunofluorescence and accumulates in the culture fluid. Expression of factor VIII-related antigen by these hybrid cells has been maintained for more than 100 cumulative population doublings, including more than 50 passages and three cloning steps. This is evidence that EA . hy 926 represents a permanent line.

Antigens↗

Human endothelial cell culture plaques induced by Rickettsia rickettsii.

Primary cultures of human umbilical vein endothelial cells were inoculated with plaque-purified Rickettsia rickettsii. After adsorption of rickettsiae, monolayers were overlaid with medium containing 0.5% agarose. Small plaques appeared on day 4 postinoculation, and distinct 1- to 2-mm plaques were observed on day 5. Plaquing efficiency was less than that of primary chicken embryo cells in the same medium. Human endothelial cell monolayers were susceptible to infection by R. rickettsii and underwent necrosis as demonstrated by supravital staining. The topographic association of endothelial cell necrosis and rickettsial infection in the plaque model confirmed the direct cytopathic effect of R. rickettsii on human endothelium. Uninfected cells appeared normal by supravital staining and transmission electron microscopy. This model offers the possibility of investigating rickettsial pathogenesis and mechanisms of enhanced severity of Rocky Mountain spotted fever in specific genetically determined conditions.

Cells, Cultured↗

Endothelial cell hybrids and the suspension of factor VIII related antigen expression.

Hybrid somatic cell clones have been generated by fusing human vascular endothelial cells in primary culture to cells of four rodent lines. Factor VIII related antigen (VIIIR:Ag) was clearly demonstrable in the cultured endothelial cells, even when they had been co-cultured with rodent cells. But in none of 14 hybrid clones was VIIIR:Ag detectable. Isozyme analyses for human chromosome markers show that all the assayed human chromosomes were represented among the hybrids, and that various subsets of human chromosomes have been deleted from individual hybrid clones. It may be concluded, therefore, either that VIIIR:Ag production depends on a particular combination of human chromosomes not represented in any of the hybrids, or that the rodent cells contribute some agent which intracellularly blocks VIIIR:Ag expression.

Antigens↗

Expression of feline xenotropic RNA tumor virus in hybrids between permissive human and non-permissive mouse cells.

Somatic cell hybrids were generated by fusing human (A549) cells, cloned after infection with the feline xenotropic CCC virus, to mouse (3T3) cells which are non-permissive for this virus. Hybrid clones were found to be capable of expressing infectious virus. CCC virus expression, however, was regulated in the hybrid cells in such a way that 20-200 times less virus was released into the culture fluid than by the human parental line. Thus human permissiveness for this virus is co-expressed with murine restriction. Markers for twenty human chromosomes were assayed in the hybrid clones. No single human chromosome was found to be essential and sufficient for CCC virus production, since none of them was consistently present or lost in virus-positive and virus-negative clones, respectively.

Animals↗

Suppression of malignancy in human lung cancer (A549/8) times mouse fibroblast (3T3-4E) somatic cell hybrids.

Interspecies hybrid cells were formed by the fusion of two parent cells: 1) the human lung cancer (bronchioloalveolar) line A549/8, which is not contact inhibited, rapidly produces tumors in athymic nude (nu/nu) mice, and forms colonies in agarose, and 2) the mouse fibroblast line 3T3-4E, which is contact inhibited, is nontumorgenic in nuce mice, and does not form colonies in agarose. These hybrid cells were tested 40-50 generations after fusion. The presence of 20 of the 23 different human chromosomes was tested by isoenzyme analysis, and examples of expression of each isoenzyme marker were found in at least some hybrid clones. All 14 independent hybrid clones tested were nontumorigenic in nude mice. Testing of hybrid clones for their ability to form colonies in agarose revealed two distinct phenotypes: agarose (clones forming colonies at 1-4% of the plated cells) and agarose (no colonies formed/10(5) cells tested). These phenotypes were discordant with all human isoenzymes tested. Malignant human lung cancer A549/8 times non-malignant mouse 3T3-4E cell hybrids were nontumorigenic in nude mice; thus malignancy of the bronchioloalveolar lung cancer behaved as a recessive trait. This nontumorigenicity was not accounted for by an absolute loss of the human chromosomes tested, but gene dosage may play a role. In contrast, the ability to clone in agarose was expressed in some hybrids (and thus behaved as a dominant trait); at present, agarose clonability cannot be related to specific human chromosomes.

Animals↗

Prenatal diagnosis by linkage: hemophilia A and polymorphic glucose-6-phosphate deydrogenase.

Close linkage between the loci for G6PD and hemophilia A allows prenatal diagnosis of hemophilia in the fetuses of certain women who are heterozygous for two electrophoretic types of G6PD. A pregnant woman, whose mother was an obligate heterozygote for hemophilia, had factor VIII levels and a G6PD phenotype that failed to indicate clearly whether or not she was heterozygous for hemophilia. The G6PD phenotype of her male fetus revealed that the fetus was unlikely to have hemophilia.

Female↗