Biomedical subjects

M M Wilkinson

Publications and source records attributed to M M Wilkinson.

23 records · Page 2Linked to original sources

PubMed1983

Organ-related differences in binding of Dolichos biflorus agglutinin to vascular endothelium.

We screened cryostat sections of tissues from 10 inbred strains of mice with a panel of conjugated lectins, in a search for polymorphisms which could be used as markers in mouse chimeras. In DDK and RIII mice, but not the other strains tested, there are binding sites on the membrane of vascular endothelial cells for Dolichos biflorus agglutinin (DBA), which is specific for terminal nonreducing N-acetyl galactosamine residues. The expression of DBA binding sites on RIII and DDK endothelium is not, however, uniform: there are consistent differences between blood vessels in different organs. These observations provide evidence of an organ-related heterogeneity in vascular endothelium which is open to biochemical analysis, and which raises the possibility that endothelial cells carry a "tissue address."

Animals↗

PubMed1983

Immunohistochemical demonstration of H2 antigens in mouse tissue sections.

The immunohistological demonstration of H2 antigens in cryostat sections of a wide variety of mouse tissues is reported. The purpose in developing the method was to use H2 antigens as cellular markers in studies of mouse chimeras. Monoclonal anti-H2 antibodies were used, either with a hapten-sandwich technique using biotin or arsanilate, or as direct enzyme conjugates. The direct antibody-enzyme conjugates were simpler to use, provided an intensity of specific staining which was comparable to that obtained with the hapten-sandwich systems, and gave fewer problems of background when simultaneous double staining was attempted. The results provide a description of the distribution of H2 antigens in many of these tissues. The intensity of H2 staining varied widely from tissue to tissue, but also within tissues and between individual mice of the same litter. Quantitation by autoradiography suggests that there is a fivefold variation in available H2 antigen between tissues which are stained strongly or weakly by our technique.

Animals↗

PubMed1983

H-2 antigens as markers of cellular genotype in chimaeric mice.

We describe an immunohistochemical method, using monoclonal anti-H-2 antibodies, for demonstrating H-2 antigens in cryostat sections of a variety of mouse tissues. Double staining allows simultaneous demonstration of both cell populations in tissue sections from H-2b in equilibrium H-2k aggregation chimaeras.

Animals↗

PubMed1981

Inhibition of endogenous tissue alkaline phosphatase with the use of alkaline phosphatase conjugates in immunohistochemistry.

In mammals there are two forms of alkaline phosphatase, one of which is widely distributed in a variety of tissues, and one of which is confined to intestine. Levamisole (1-tetramisole) inhibits the nonintestinal form of the enzyme, but is without effect on the intestinal form. We have exploited this difference by using conjugates made with calf intestinal alkaline phosphatase for immunohistochemical demonstration of H2 antigens in frozen section of mouse tissues. The alkaline phosphatase staining is performed in the presence of 1 mm levamisole, which inhibits the endogenous tissue enzyme without loss of staining by the conjugate. Endogenous enzyme can be inhibited by other means, such as exposure to 20% acetic acid, but labile antigens may be destroyed.

Acetates↗

PubMedDate not supplied

Derivation of mouse intestinal crypts from single progenitor cells.

Adult intestinal epithelium consists of a sheet of single-cell thickness which is morphologically highly organized into tubular invaginations (crypts) and finger-like projections (villi). Proliferation of the cells is confined to the base of the crypts, from which cells migrate to the villi, where they are shed. The villi are formed during embryogenesis from a multilayered epithelium. In mice, crypts develop at about the time of birth from the epithelium between the villi, which by this stage is no longer multilayered. So far it has remained unknown how many progenitor cells contribute to each crypt, and whether they develop by the proliferation of already committed progenitors, or as a result of local inductive tissue interactions. Here, we have used mouse aggregation chimaeras as an experimental system to demonstrate immunohistochemically that the epithelium of individual crypts in small and large intestine of adult mice is always composed of cells of a single parental type. We have confirmed that this result is not an artefact of the chimaeric system by examining female mice that are mosaic for the X-linked alleles Pgk-1a and Pgk-1b. We conclude that the epithelium of each adult crypt is derived from a single progenitor cell.

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