Search PubMed⌕ Search

Biomedical subjects

G Davey

Publications and source records attributed to G Davey.

36 records · Page 2Linked to original sources
PubMed1999

Reduced expression of (alpha)5(beta)1 integrin prevents spreading-dependent cell proliferation.

Cell adhesion to substratum results in the initiation of integrin signaling and an integrin-dependent organization of the cytoskeleton (cell spreading). To address the potential relationships between these events and cell proliferation, we transfected NRK fibroblasts with an antisense cDNA encoding a 1.3 kb ATG-spanning portion of (alpha)5 integrin subunit and obtained stable clones in which the surface expression of (alpha)5(beta)1 integrin was selectively reduced. (alpha)5-antisense NRK cells are less spread than the control transfectants, have poorly defined stress fibers, and an increased amount of cortical actin. The antisense clones remained anchorage-dependent, but they proliferated very slowly. Serum dose-response curves showed that they have an impaired response to mitogens. Importantly, cell spreading and stress fiber formation could be completely restored by plating the antisense cells on collagen, but cell spreading failed to rescue proliferation. These data indicate that cell spreading can be uncoupled from cell proliferation and that cytoskeletal organization is important for NRK cell proliferation because it enforces the proliferative effect of (alpha)5(beta)1 integrin. Our results also indicate that reduced surface expression of (alpha)5(beta)1 integrin is not sufficient to confer the anchorage-independent phenotype to nontransformed cells.

Animals↗
PubMed1998

Doping in sport.

Explore the source record for details and available documents.

Adult↗
PubMed1996

Stability of vitamins A, C, and E, carotenoids, lipids, and testosterone in whole blood stored at 4 degrees C for 6 and 24 hours before separation of serum and plasma.

To investigate whether overnight storage causes significant changes in whole blood, we measured serum and plasma concentrations of vitamins A, C, and E, carotenoids, lipids, and testosterone in whole blood samples stored in a refrigerator at 4 degrees C for 6 and 24 h before centrifugation, aliquoting and freezing them at -70 degrees C or below. In comparison with baseline samples prepared within 2 h, the mean percentage changes at 24 h were: -3.0% to +1.0% for retinol, alpha-tocopherol, and gamma-tocopherol in plasma; -8.7% to -0.1% for carotenoids in plasma; -7.2% for vitamin C in plasma and -1.8% for vitamin C in serum; -2.7% to +2.4% for lipids in serum; and +0.4% to +6.2% for testosterone in serum and plasma from men and women. Spearman's rank correlation coefficients between measurements made in the baseline samples and those made after storage for 24 h were greater than 0.9 for 11 analytes, between 0.8 and 0.9 for 7 analytes, and less than 0.8 for only 1 analyte (vitamin C in serum). The ratio of between-subject to within-subject coefficients of variation was greater than 3.0 for all analytes except lutein (ratio, 1.6), alpha-cryptoxanthin (ratio, 2.4) and vitamin C (ratio in serum, 3.0; ratio in plasma, 2.2). We conclude that storage of whole blood at 4 degrees C for 24 h before freezing does not cause important changes in the analytes studied and that this delay in processing may be incorporated in the design of large prospective studies.

Ascorbic Acid↗
PubMed1990

Lack of correlation between immunoglobulin and T cell receptor gene rearrangements and TdT expression in acute myeloid leukaemia.

Thirty-two cases of acute myeloid leukaemia (AML) were examined for expression of terminal deoxynucleotidyl transferase (TdT) and rearrangements of the genes coding for the immunoglobulin heavy chain and the beta chain of the T cell receptor, in order to establish whether these two forms of lineage infidelity are linked. In 17 cases of AML with greater than or equal to 10% TdT+ cells, three cases showed evidence of gene rearrangement, two having clonal rearrangements in the immunoglobulin gene and one with a rearranged T cell receptor gene. Among 15 AML cases without significant numbers of TdT-positive blasts, three cases had rearrangements in both immunoglobulin and T cell receptor genes, while a fourth case had an immunoglobulin gene rearrangement. No relationship was seen between lymphoid gene rearrangements and expression of the lymphoid surface antigens CD7 and CD10. The lack of association between TdT expression and gene rearrangements does not support the concept of an orderly activation of the recombinase machinery in those cases of AML with features of early lymphoid differentiation.

Adolescent↗
PubMed1978

Adjustable lead glass shielding device for use with an over-the-table x-ray tube.

Sources of scattered radiation exposure to personnel from a ceiling-mounted x-ray tube were examined at the side of cardiac catheterization patients. A fully adjustable mounting for a lead glass shield was designed to afford maximum radiation protection to the attending physician's head and neck area, while minimizing interference with the procedure.

Glass↗
PubMed1975

Localisation and pathology of Mortierella wolfii toxin in mice.

Using 125I labelled M. wolfii toxin the site of action in mice was shown to be the kidney. Autoradiographic studies revealed the label to be localised in the proximal convoluted tubules of the kidney, where there was a marked necrosis and degeneration of the epithelium causing the tubules to become considerably distended. Although the distal and collecting tubules maintained their integrity, many contained amorphous casts. An injected dose of 1 toxic unit (10 mug protein) was sufficient to produce damage to the kidney with subsequent anaemia, azotemia and albuminuria. Other organs appeared to be essentially normal and renal failure was the probable cause of death of mice.

Animals↗
PubMed1973

Purification and properties of a toxin isolated from Mortierella wolfii.

A substance toxic for mice has been extracted from the washed mycelia of Mortierella wolfii. This toxin could also be demonstrated in culture fluids after spontaneous autolysis of the fungal hyphae. Purification of the toxin was carried out using Sephadex chromatography (G-200, G-50) and resulted in a single band on sodium dodecyl sulfate polyacrylamide gels. Properties of the toxin included heat lability at 60 C, trypsin sensitivity, activity over a wide pH range, and a molecular weight of 23,600. The mean lethal dose for 16-week-old male mice was 3.3 mug of protein.

Animals↗
PubMedDate not supplied

Cancer near nuclear installations.

The OPCS report on cancer incidence and mortality in the vicinity of nuclear installations in England and Wales provides a mass of information that is so large that it should be possible to detect quite small changes in disease levels with considerable confidence. The data on cancer mortality are less subject to selective bias than the registration data on which incidence rates are based, and they provide the firmest grounds on which evidence of any effect can be obtained. These data show conclusively that there has been no general increase in cancer mortality in the vicinity of nuclear installations in a 22-year period beginning several years after the opening of the installations that have released the largest amounts of radionuclides to the environment. On the contrary, the mortality from cancer has tended to be lower in the LAAs in the vicinity of nuclear installations than in control LAAs selected for their presumed comparability with the former. This is unlikely to be due to a protective effect of ionizing radiation and suggests that, despite the efforts that were made to choose comparable control areas, there were non-installation differences between the populations relevant to the risk of dying from one or other type of cancer. Detailed examination of the few types of cancer that were relatively more common in the installation areas suggest that several of the differences were most likely to be due to chance, diagnostic artefacts or social factors rather than to any hazard specifically related to the installations. One disease provides a possible exception: namely, leukaemia in the age group 0-24 years. Two other diseases need further investigation, multiple myeloma and Hodgkin's disease in the older age group 25-74 years. The excess mortality rates recorded from these cancers were not large, and it has yet to be established that they are not due to general confounding by other environmental or socio-economic factors.

Age Factors↗
PubMedDate not supplied

Significant endogenous synthesis of nitrate does not appear to be a feature of influenza A virus infection.

There is much concern about the role of nitrate in the formation of carcinogenic N-nitroso compounds. There has been renewed interest in the endogenous formation of nitrate arising as a host response to infection. This study was designed to investigate whether the large increases in nitrate excretion rate reported (6-15-fold) for certain infectious diseases is also a feature of systemic influenza infections. Volunteers were challenged either with an attenuated strain of influenza A virus or with saline; and excreted nitrate was measured in subsequent 24-h urine samples. Both with and without adjustment for potential confounding by dietary and other factors, it was clear that neither mild nor moderate influenza A virus infection resulted in substantial endogenous nitrate biosynthesis since all the variation in urinary nitrate excretion observed was within the range of normal daily fluctuations. It remains possible that a stronger and more consistent nitrate excretion response might be observed in other infectious illnesses with greater systemic disturbance.

Adult↗