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D W James

Publications and source records attributed to D W James.

At least 37 records · Page 2Linked to original sources
PubMed1982

Rapid single-step method for purification of polymorphonuclear leucocytes from blood of patients with rheumatoid arthritis.

Previous studies have shown that blood samples from healthy subjects and patients with a variety of different diseases separate into distinct mononuclear leucocyte (MNL) and polymorphonuclear leucocyte (PMNL) bands when centrifuged on a Ficoll-Hypaque medium of density 1.114 g/ml. Results from the present study showed that blood samples from patients with rheumatoid arthritis (RA) failed to separate into discrete cellular fractions under the same conditions. In particular, the PMNL were not recoverable because the erythrocytes only partially sedimented. However, following modification of the separation medium involving (a) reduction in the final Ficoll concentration from 8% to 7%, and (b) an alteration in the ratio of meglumine Hypaque:sodium Hypaque from 5.7:2.8 to 2.0:7.5, a clear band of PMNL of high purity could be obtained with blood samples from patients with RA. The modification of this previously described, simple, brief, one-step, density gradient centrifugation method achieved separation of peripheral blood PMNL required for studies of leucocyte function in patients with RA.

Arthritis, Rheumatoid↗
PubMed1981

Affinity of chick microglia in vitro for ricin 120.

The distribution of binding sites for ricin 120 in cell cultures of spinal cord from the chick embryo was examined. A characteristic pattern was observed, which remained similar in cultures fixed by a variety of methods. Light microscopy demonstrated that the most prominent staining was of small rounded or amoeboid cells. Electron microscopy showed that ricin was bound over their entire surfaces. The ultrastructural characteristics of these cells suggest their identification as microglia.

Animals↗
PubMed1980

Tubulin immunohistochemistry. Fixation methods affect the response of spinal cord cells in vitro.

We report here the results observed when tubulin fluorescence immunohistochemistry is performed upon dissociated cultures of nervous tissue, principally of chick embryo spinal cord. When fixation includes nonpolar solvents or detergents, a uniform fluorescence is seen in neuron perikarya (with the exception of their nuclei), and the processes to which they give rise. Fixation with formaldehyde or glutaraldehyde alone, however, results in a discontinuous staining of neurites, and a less regular staining of their perikarya. The former pattern of response can be elicited if aldehyde fixation is followed by exposure to non-polar solvents. Such results are obtained both in thinly spread regions of the cultures, where neurons and their processes can easily be seen, and in the cell aggregates that also characterise them. Possible interpretations of these results are discussed.

Animals↗
PubMed1980

Effects of Several Tunicamycin-like Antibiotics on Glycoprotein Biosynthesis in Mung Beans and Suspension-cultured Soybean Cells.

The antibiotics Streptovirudin and 24010 were tested to determine their effects on the formation of lipid-linked saccharide intermediates associated with glycoprotein biosynthesis in mung bean (Vigna radiata) and suspension-cultured soybean cells (Glycine max cv. Mandarin). In vitro both compounds strongly inhibited the transfer of N-acetyl[(3)H]glucosamine from UDP-N-[(3)H]acetylglucosamine to N-acetylglucosaminyl-pyrophosphoryl-polyisoprenol and lipid-linked oligosaccharides, although they had no apparent effect on the incorporation of [(14)C]mannose from GDP-[(14)C]mannose into mannosyl-phosphoryl-dolichol with a small inhibition into lipid-linked oligosaccharides. In vivo, Streptovirudin and tunicamycin dramatically inhibited the incorporation of N-[(14)C]acetylglucosamine and [(3)H]mannose into Pronase-released material (glycoproteins), whereas there was no effect on [(3)H]leucine incorporation into Pronase-released material (protein). Because the action of Streptovirudin and antibiotic 24010 in plants and other systems is similar to that for tunicamycin, these antibiotics are believed to be closely related. The use of tunicamycin is discussed with respect to its importance in studying glycoprotein biosynthesis and function in animal and plant systems.

Journal Article↗
PubMed1980

Effect of cold on endogenous fucosyl transferase activity in corn roots.

Incubation of excised, 1-centimeter long root tips of corn in chilled distilled H(2)O increases the activity of extractable GDP fucose: polysaccharide fucosyl transferase. Enhancement of transferase activity is optimal at 10 C and incubation at this temperature for 8 hours causes a 3- to 5-fold stimulation of activity. Transfer of roots from 10 to 30 C reverses the enhancement of enzyme activity although reciprocal transfer of roots from 30 to 10 C does not stimulate the accumulation of transferase activity.

Journal Article↗
PubMed1980

Antirheumatic activity of fenclofenac.

This study has set out to establish whether fenclofenac has an antirheumatic effect in addition to its anti-inflammatory and analgesic activity. The results show that during the course of a 6-month study the drug improved clinical parameters, including the articular index, early morning stiffness, ring sizes, and grip strength, and produced changes in laboratory measurements such as the levels of C-reactive protein, IgG, and rheumatoid factor.

Adolescent↗
PubMed1979

Characterization of GDP-Fucose: Polysaccharide Fucosyl Transferase in Corn Roots (Zea mays L.).

The peripheral root cap cells of corn (cv. SX-17A) secrete a fucose-rich, high molecular weight, polysaccharide slime via the dictyosome pathway. To study the synthesis of this polysaccharide, a technique for isolating and assaying GDP-fucose:polysaccharide fucosyl transferase activity was developed. Corn roots were excised from germinated seeds, incubated 12 hours at 10 C in water, and ground in 100 millimolar Tris or Pipes buffer (pH 7.0) with or without 0.5 molar sucrose. The membrane-bound enzyme was solubilized by sonication in the presence of 2 molar urea and 1.5% (v/v) Triton X-100 and assayed by monitoring the incorporation of GDP-[(14)C]fucose into endogenous acceptors. Optimum enzyme activity is expressed at pH 7.0 and 30 C in the presence of 0.8% (v/v) Triton X-100. The enzyme does not require divalent cations for activation and is inhibited by concentrations of MnCl(2) or MgCl(2) greater than 1 millimolar. Corn root cap slime will serve as an exogenous acceptor for the enzyme if it is first hydrolyzed in 5 millimolar trifluoroacetic acid for 60 minutes at 18 pounds per square inch, 121 C. This procedure prepares the acceptor by removing terminal fucose residues from the slime molecule. Kinetics of fucose release during hydrolysis of native slime and in vitro synthesized product suggests that the two polymers possess similar linkages to fucose.

Journal Article↗
PubMed1979

Intracellular Localization of GDP-Fucose: Polysaccharide Fucosyl Transferase in Corn Roots (Zea mays L.).

The intracellular site of synthesis of the fucose-rich polysaccharide slime secreted by corn roots was localized by monitoring the distribution of GDP-fucose:polysaccharide fucosyl transferase activity in subcellular fractions of corn roots. Root tip sections were chopped in the presence of 0.56 molar sucrose and 100 millimolar Tris (pH 7.0). After a brief centrifugation, the homogenate was applied to a Sepharose 4B column (1.5 x 30 cm). The turbid, particulate portion of the supernatant fraction eluted at the void volume. Ninety per cent of the enzyme activity was found in the pooled particulate fractions. The particulate fraction was purified on linear sucrose gradients. Gradient fractions were characterized by buoyant density, 280 nanometer absorbance, electron microscope observation, and distributions of NADH-cytochrome c oxidoreductase and fucosyl transferase activities.TWO PEAKS OF FUCOSYL TRANSFERASE ACTIVITY WERE OBSERVED: one in fractions rich in smooth endoplasmic reticulum, and another in fractions rich in dictyosome cisternae and dictyosome vesicles. The data suggest that the synthesis of corn root slime begins in the endoplasmic reticulum and is completed in the dictyosomes prior to secretion; however, the possibility that more than one fucosyl transferase exists in corn roots is discusses.

Journal Article↗
PubMed1979

Directed migration of circulating polymorphonuclear leucocytes in patients with rheumatoid arthritis: a defect in the plasma.

The migration of peripheral polymorphonuclear leucocytes (PMNs) of patients with rheumatoid arthritis has been studied both in vivo and in vitro. A significant reduction in the accumulation of PMNs in skin chambers in patients with rheumatoid arthritis compared to controls was observed but no defect in cell movement was detected when the isolated PMNs from the patients were exposed to activated control plasma. However, when PMNs from the control group were tested against activated plasma from patients with rheumatoid arthritis there was a significant decrease in their chemotactic response. It is proposed that there is a humoral defect in the plasma of the patients.

Adult↗
PubMed1979

Abnormal polymorphonuclear leucocyte chemotaxis in Behçet's syndrome.

Experiments both in vitro and in vivo have been performed to study the chemotactic response of polymorphonuclear leucocytes (PMNs) in Behçet's syndrome. The experimental results were apparently contradictory. Using modified Boyden chambers we found that the PMNs from patients with Behçet's syndrome responded to a greater extent in vitro than normal cells, but with skin chambers placed over abrasions the in vivo response was less than normal. The significance of these findings is discussed and related to the histological appearances that may be seen in this condition.

Adult↗
PubMed1979

A comparison of two in vitro methods for studying a defect in leucocyte movement in rheumatoid arthritis.

Filter and agarose plate techniques have been used to study an abnormality of polymorphonuclear leucocyte movement in patients with rheumatoid arthritis. The chemotactic response of normal cells towards activated rheumatoid plasma was significantly less than that towards activated control plasma when examined in Boyden chambers. This defect was not observed using the agarose plate method where the response of both control and rheumatoid cells towards activated rheumatoid plasma was identical. The existence of the plasma defect, which has been shown to be cell-directed, would not have been apparent had the agarose plate method been used alone. The choice of suitable in vitro methodologies for studying leucocyte movement in pathological conditions is therefore of some importance.

Arthritis, Rheumatoid↗
PubMed1978

Gold lung.

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Adult↗
PubMed1977

The development and ultrastructure of previously dissociated foetal human cerebral cortical cells in vitro.

Cells from foetal human cerebral cortex were mechanically dissociated and subsequently maintained in vitro for periods ranging between three and twenty-eight days. The ultrastructure of these cells at different stages of their development in culture was extensively examined. Nuclear and cytoplasmic features were extremely variable and a wide range of cell types was evidently represented. Of the three principal cell types found i.e. neurons, neuroglia and mesenchymal cells, only a minority of cells was classified with confidence, particularly during the first two weeks in culture. Extensive intercellular junctions of the adhaerens variety, common after 14 days in vitro were present at an earlier stage of development than synaptic profiles. First indications of synapse formation were observed after 21 days in vitro and after 24 days presynaptic sites filled with synaptic vesicles and with well defined presynaptic and postsynaptic thickenings were found. The significance of some of the features observed are both considered and discussed.

Cerebral Cortex↗
PubMed1975

Myelin formation in cultures of previously dissociated mouse spinal cord.

Myelin formation in cultures of previously dissociated spinal cord from foetal mice is described. In addition to the expected pattern of myelination, in which axons are closely wrapped by myelin lamellae, redundant folds of myelin have been found, as have double sheaths surrounding a single axon. Hypotheses concerning the generation of these appearances are discussed. It is suggested that certain intracytoplasmic laminar bodies found in oligodendrocytes in vitro may be of mitochondrial origin.

Animals↗
PubMed1975

The culture of previously dissociated embryonic chick spinal cord cells on feeder layers of liver and kidney, and the development of paraformaldehyde induced fluorescence upon the former.

Spinal cord cells from embryonic chicks were cultured upon liver and kidney feeder layers of similar species origin. Successful cultures were obtained with inocula of cord cells containing as few as 15 000 cells ml(-1), whereas without feeder layers at least 200 000 ml(-1) are ordinarily required. Upon liver, many neurons and processes became intensely fluorescent, a property seldom shared by those grown upon kidney. Many processes upon liver contained large numbers of dense-cored vesicles, significantly larger and more numerous than in those grown upon kidney. We conclude that association with liver feeder layers has the consequence of producing in cord cells fluorescence and ultrastructural characteristics appropriate to catecholamine content, through a mechanism as yet unknown.

Animals↗