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M W Ho

Publications and source records attributed to M W Ho.

11 recordsLinked to original sources
PubMed1991

Mosaic pattern of lactase expression by villous enterocytes in human adult-type hypolactasia.

Immunohistological analysis of the expression of lactase protein in adults with hypolactasia has been carried out using monoclonal antibodies. Eight different antibodies that recognize at least three distinct epitopes on the lactase protein each gave the same result. Strong brush border staining was observed in all the lactase-persistent adults. No staining at all was detected in 9 of the hypolactasic subjects. In the remaining 12 individuals a mosaic pattern of expression was observed: small patches of enterocytes stained strongly, whereas the surrounding areas showed no staining at all. Sucrase-isomaltase, in contrast, showed no such mosaicism in these or in any of the other individuals. The mosaicism observed in the 12 hypolactasic individuals suggests that the differentiation of the columnar cells along the villus is not homogeneous. Furthermore, the existence of two patterns of expression of the lactase protein in the lactase-deficient individuals (i.e., absence of protein and mosaicism), if characteristic of the entire length of the intestine of the individuals tested, would suggest the existence of two phenotypes of adult-type hypolactasia in the population studied.

Antibodies, Monoclonal↗
PubMed1990

An exercise in rational taxonomy.

The quest for a rational taxonomy of living forms began in the 17th century. Since the general acceptance of Darwin's theory of descent with modification, however, students of morphology became preoccupied with a systematics based on the genealogy of groups; and the rise of molecular phylogenies in recent years results in a further decline in the science of morphology. Reconstructing phylogenies by itself brings us no closer to the goal of rational taxonomy, which is to uncover the natural order inherent in the forms of living things. It is proposed that the rational taxonomy of forms should be derived from a study of development, much as von Baer had envisaged. To illustrate the method, a set of segmentation abnormalities in Drosophila larvae (previously exposed to either vapour) is considered, which can be individually classified as distinct disturbances in the process responsible for establishing normal segmental pattern. The process consists of a hierarchy of four successive bifurcations dividing the embryo's body first into two parts, then four, eight, and finally 16 subdivisions or segments. This gives rise to a taxonomic map of all possible transformations which contains the "phylogeny" of the actual forms and provides a natural system for classifying them. Attempts to recover the "true" phylogeny by various numerical methods are summarized and their implications for the validity of the basic assumptions of contemporary systematics discussed.

Animals↗