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M Wallis

Publications and source records attributed to M Wallis.

116 records · Page 7Linked to original sources
PubMed1966

A chromatographic preparation of ox growth hormone.

1. A method is described for the chromatographic preparation of ox growth hormone. It involves chromatography of an extract of anterior pituitary lobes on DEAE-cellulose, followed by rechromatography on a dextran gel of low cross-linkage (Sephadex G-100). 2. The product is highly active in growth-hormone assays, and is obtained in good yield. It was homogeneous by several criteria, but showed some heterogeneity on starch-gel electrophoresis. 3. The molecular weight of the hormone was estimated from its behaviour on gel-filtration columns under various conditions. Evidence that the hormone may dissociate into sub-units under some conditions is presented.

Journal Article↗
PubMedDate not supplied

Binding specificity of monoclonal antibodies towards the size variants of human growth hormone.

The expression of antigenic determinants on size variants of human growth hormone (hGH) has been investigated using monoclonal antibodies of distinct combining-site specificity. Monomeric, dimeric, trimeric and polymeric (very high-molecular-weight) forms of hGH were separated by gel filtration on Sephadex G-100, and their antigenic potency was determined quantitatively by competition with 125I-labelled hGH for binding to each of four different monoclonal antibodies. With three of these antibodies the potencies of monomeric, dimeric and trimeric hGH were not significantly different, and the polymeric material was 11-13% as potent as the monomer. However, using one antibody (NA 71) the antigenic potencies of dimeric and trimeric hGH were lower (30-50%) than that of the monomer, and the polymeric material was only about 5% as potent as the monomer. These results suggest that the determinant with which antibody NA 71 interacts is close to the site of interaction between hGH monomers and apparently partially 'masked' in dimers, trimers and polymeric hGH.

Antibodies, Monoclonal↗
PubMedDate not supplied

Involvement of calcium ions in dopamine inhibition of prolactin secretion from sheep pituitary cells.

The involvement of calcium in the regulation of prolactin secretion and a possible inhibitory mechanism of action for dopamine have been investigated. Basal prolactin secretion from cultured ovine pituitary cells was dependent on the concentration of calcium ions (Ca2+) in the medium and was inhibited by the presence of verapamil (10 microM). The divalent cation ionophore A23187 (1 microM) caused a rapid stimulation of prolactin release from the cells. The effect was essentially complete within 10 min and subsequently secretion of prolactin occurred at close to the basal rate. A23187 had no effect on cell cyclic AMP levels. Dopamine (0.1 microM) but not verapamil (10 microM) inhibited the A23187 (10 microM) induced release of prolactin. Inhibition of basal and A23187 (1 microM) stimulated prolactin secretion occurred over a similar range of dopamine concentrations. The dopamine receptor antagonist haloperidol (1 microM) reversed the inhibitory effect of dopamine (0.1 microM) on A23187-stimulated prolactin release. These results provide evidence to support the concept that control of Ca2+ handling by lactotrophs may be of fundamental importance in the regulation of prolactin secretion.

Animals↗
PubMedDate not supplied

Deep vein thrombosis: clinical nursing management.

The occurrence of a deep vein thrombosis is potentially life threatening and rapid assessment and treatment are essential to prevent development of a pulmonary embolism. Prophylaxis and risk assessment are important aspects of DVT management.

Anticoagulants↗