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Biomedical subjects

B A Hodson

Publications and source records attributed to B A Hodson.

11 recordsLinked to original sources
PubMed1991

Novel affinity chromatographic system for the single-step purification of glycosaminoglycans from complex systems using volatile buffers.

A new system for the isolation and purification of glycosaminoglycans (GAGs) and related molecules from complex systems such as plasma is described. Affinity chromatography which exploits the very high affinity between the polymeric base Polybrene and sulphated polysaccharides was used. A novel volatile buffer system composed of ammonium formate and formic acid, which allows the complete recovery of samples, was developed, and elution conditions were optimised for the separation and purification of GAGs of different charge densities. Using this system the losses associated with dialysis and desalting, frequently necessary preliminaries to further analysis, are avoided.

Buffers↗
PubMed1989

The absorption, clearance and metabolic fate of dermatan sulphate administered to man--studies using a radioiodinated derivative.

An iodinated derivative of dermatan sulphate was administered by the intravenous, subcutaneous and oral routes to healthy human volunteers in conjunction with unlabelled dermatan sulphate. Following intravenous injection clearance of radiolabel and concentration as measured by competitive binding assay were highly correlated and displayed complex kinetics which were not dose-dependent. Intact 125I-dermatan sulphate was absorbed following both subcutaneous and oral administration, though there appeared to be selective uptake by the gut of a subfraction comprising the smaller or less sulphated molecules. The intact material was subsequently excreted unchanged in the urine. Degradation products of dermatan sulphate were not detected by either gel filtration or affinity chromatography on Polybrene-Sepharose at any time in either plasma or urine, indicating that administered dermatan sulphate is not catabolised by man.

Absorption↗
PubMed1986

Oligoclonal tumours.

Tumours are commonly classified as monoclonal or polyclonal. The question of how many clones are present in a polyclonal tumour is seldom asked; it is important, however, because the answer may show whether or not clones arise and develop independently, and whether the number of clones in tumours of a particular kind tends to increase or decrease with time. We have used two procedures to assess the clonality of chemically-induced murine fibrosarcomas, one based on the heterozygosity of the tumour hosts for an X-linked marker, the other on the expression of tumour-associated transplantation antigens (TATA) by the tumours. As we have reported previously, many of these tumours are pleoclonal. Evidence now presented suggests that the clones do not develop independently and that many of the tumours are biclonal.

Animals↗
PubMed1986

The effect of passage in vivo and in vitro on the properties of murine fibrosarcomas: III. Cell surface molecules and production of growth factors.

Three factors may be responsible for the sharp difference in tumourigenicity between cloned murine fibrosarcoma lines maintained in vitro, and cells of the same lines after in vivo passage, initially in a T cell deficient mouse and subsequently in normal mice: acquisition during passage of resistance to NC cells; acquisition during passage of a surface molecule, probably a sialic acid, which protects the cell against T cell-mediated lysis; and ability of the passaged cells, but not the non-passaged cells, to produce sufficient amounts of autocrine growth factors necessary for growth in vivo. The tumourigenicity of the passaged cells cannot be attributed to failure to express TATA or MHC class I molecules.

Animals↗
PubMed1985

The effect of passage in vitro and in vivo on the properties of murine fibrosarcomas. II. Sensitivity to cell-mediated cytotoxicity in vitro.

The sensitivity of cultured and mouse-passaged cloned lines of chemically-induced murine fibrosarcomas to killing by NK and NC cells, and to cell-mediated immunity, has been studied in in vitro assays, using target cells labelled with 51Cr or 125IUDR. None of the lines tested proved sensitive to NK cells. Three cultured lines were, at most, only slightly sensitive to NC cells; a fourth cultured line was moderately sensitive and became less so, but not completely insensitive, after passage in susceptible hosts. The primary object of these experiments was to test the hypothesis that cultured cell lines which ordinarily fail to grow in normal mice are able to grow after being passaged in a susceptible immunodeficient host because, during this passage, they become resistant to NK or NC cells. This has been shown to occur with one clone, but will not serve as a general explanation because, with other clones, both cultured and mouse-passaged lines were NC-insensitive. The cell-mediated immunity assays confirm our previous conclusion that cultured and mouse-passaged lines of the same clone differ little, if it all, in immunogenicity.

Animals↗
PubMed1985

The effect of passage in vitro and in vivo on the properties of murine fibrosarcomas I. Tumorigenicity and immunogenicity.

Cloned cell lines of chemically-induced murine fibrosarcomas maintained in tissue culture usually fail to grow when transplanted to normal syngeneic mice. They grow, however, in various categories of T cell deficient mice and after such passage grow readily in normal mice. Both cultured and mouse-passaged lines possess strong TATA. Three alternative explanations are suggested which might account for these findings. Emergence during the initial passage of a population of tumour cells resistant to NC cells. Acquisition during the initial passage of a protective surface molecule that interferes with the efferent side of the immune response when the tumour cells are subsequently transplanted to a normal host. Loss during the initial passage of a Class I MHC molecule which prevents dual recognition of the tumour cells by T cells when they are transplanted to a normal host. New experiments are proposed to distinguish between these possibilities.

Animals↗
PubMed1979

Accumulation of UDP-glucose pyrophosphorylase by axenically grown amoebae of Dictyostelium discoideum.

Amoebae of the slime mould Dictyostelium discoideum AX2 possess only low UDP-glucose pyrophosphorylase activity when grown on autoclaved Klebsiella aerogenes (approx. 30 units/mg of protein), but accumulate the enzyme to approx. 150-200 units/mg of protein during vegetative growth in axenic medium. The vegetative accumulation of UDP-glucose pyrophosphorylase by axenically grown cells is prevented if autoclaved K. aerogenes are included in the axenic medium, suggesting the absence of a specific inducer. Affinity chromatography using anti-(UDP-glucose pyrophosphorylase) antibody and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis indicate that the enzyme accumulated during axenic growth and that normally accumulated during development are immunologically cross-reactive and that both are composed of two subunits with mol.wts. 55,600 and 57,500 present in approximately equal amounts in the active enzyme.

Amoeba↗