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Biomedical subjects

A M Dalix

Publications and source records attributed to A M Dalix.

28 records · Page 2Linked to original sources
PubMed1983

Competition between ABO and Le gene specified enzymes. I. A Lewis related difference in the amount of A antigen in saliva of A1 and A2 secretors.

Radioimmunoassays were prepared using two anti-A and one anti-B reagents. The specificity of the procedures was assessed with 13 artificial antigens. The amounts of A and B natural antigens in saliva of ABH secretors of known Lewis phenotype were measured with these assays. The results confirmed that the average amount of A antigen is lower in Lewis-positive (Leb) than in Lewis-negative (Led) donors and in A2 than in A1 donors. However, the differences among the four combined A and Lewis phenotypes were only supported by significantly lower amounts of A antigenic determinants in A2Leb as compared to the other three phenotypes (A1Leb, A1Led and A2Led) that had similar amounts of A antigenic determinants. No Lewis-related difference could be detected in the amounts of B antigens between BLeb and BLed donors. The results are discussed in terms of competition between A, B and Lewis-gene-specified enzymes for their common acceptors. The difference in the efficiency of the A2 enzyme as compared to that of the A1 enzyme is proposed as a possible explanation for the A1-A2 phenotypic difference.

ABO Blood-Group System↗
PubMed1983

Competition between ABO and Le gene specified enzymes. II. Quantitative analysis of A and B antigens in saliva of ABH nonsecretors.

One B- and two A-specific radioimmunoassays detected A and B antigenic determinants in saliva of ABH nonsecretors. The A or B antigens found in saliva of nonsecretors had lower efficiency and higher heterogeneity, in the inhibition of the A or B assays, as compared to A or B antigens in saliva of ABH secretors. In the 3 assays, samples of nonsecretor Lewis positive donors (Lea) had less A or B antigens than samples of nonsecretor Lewis negative donors (Lec), suggesting that there is a competition between A or B and Le gene-specified products.

ABO Blood-Group System↗
PubMed1983

H-deficient blood groups of Reunion island. II. Differences between Indians (Bombay Phenotype) and whites (Reunion phenotype).

Two variants of recessive, H-deficient nonsecretor individuals (h/h, se/se) were identified on Reunion Island: (1) H-negative individuals corresponding to the classical Bombay phenotypes (OhO, OhA, OhB, OhAB) who lack completely the H antigen on their red cells; all of them were Indian and had strong anti-H antibodies reacting with normal O and Oh red cells from whites; and (2) H-weak individuals (Oh, Ah, Bh, ABh). This phenotype represented the majority (85%) of the H-deficient phenotypes on Reunion Island, and all of them were white. They had only a weak expression of the H antigen and showed small but detectable amounts of ABH antigens on their red cells. Their anti-H antibodies reacted with normal O erythrocytes, but failed to react with Oh red cells, regardless of the ethnic origin of the donor. They were all from the same geographical area on the Island (Cilaos) and showed homogeneous titers of anti-H antibodies in sera. We propose to call this particular variant of weak H phenotype, belonging to the so-called para-Bombay series, Reunion.

ABO Blood-Group System↗
PubMed1982

Distribution of H type 1 and H type 2 antigenic determinants in human sera and saliva.

A radioimmunoassay specific for the H type 1 antigenic determinant demonstrated that the H type 1 antigen is under the strict control of the Se gene in both serum and saliva. Similar amounts of H type 1 antigenic determinants were found in saliva from Se/-, le/le donors and in saliva from Se/-, Le/- donors. However, sera from Se/-, le/le donors were about 100 times more efficient in inhibiting the H type 1 assay than were sera from Se/-, Le/- donors. A radioimmunoassay, based on the binding of Ulex europaeus with the H type 2 antigenic determinant, showed that all the H type 2 antigen in saliva is under the control of the Se gene, while only one-third of the H type 2 antigen present in serum is under the control of this gene. The remaining two-thirds of H type 2 antigen in sera is independent of the ABH secretor status of the donor. The amount of H type 2 antigen in both serum and saliva is independent of the Le gene. These results are compatible with the existence of two alpha (1 leads to 2) fucosyl-transferases but suggest that the enzyme of epithelial origin, coded by the Se gene, should be able to transform both type 1 and type 2 natural substrates, while the enzyme of mesodermic origin, coded by the H gene, would work preferentially on the natural type 2 substrates.

ABO Blood-Group System↗
PubMed1980

Distribution of blood group antigen A in normal and pathologic human kidneys.

We tested this distribution with an indirect immunofluorescent technique using purified rabbit anti-A antiserum on 21 whole normal kidneys (a group, N equal to 18; AB group, N equal to 1; O group, N equal to 2) and on 349 kidney biopsy samples (A group, N equal to 140; AB group, N equal to 14; O or B group, N equal to 195) representing a large spectrum of renal diseases. In normal kidneys from A and AB groups, the A antigen was detected in the whole vascular endothelium and in the convoluted distal tubules. In secretors, collecting tubules were brightly positive. Epithelial staining was more diffuse in the inner part than it was in the outer part of the medulla. The basement membrane of the inner collecting tubules was positive in frozen sections but not in paraffin sections. In pathologic kidneys, modifications were obvious: (1) The thickened basement membrane of atrophic convoluted distal tubules was brightly stained. (2) Endothelial staining allowed a precise appreciation of the glomerular and interstitial vasculature. (3) In proliferative changes such as arterial intimal proliferation, proliferative glomerulonephritis, and interstitial cell infiltration, endothelial cells do not proliferate. This routine staining technique of endothelial cells by anti-A antiserum provide information not obtainable with light microscopy.

ABO Blood-Group System↗
PubMed1977

Radioimmunoassay of the WZ polymorphic antigens of normal human colon and their relationship with ABH antigenic determinants.

Heat resistant, high mol. wt glycoproteins of the three WZ phenotypes (W+Z+, W-Z+ and W-Z-) were extracted from normal human colonic mucosa and labelled with 125I. More than 80 per cent of the radioactivity of the W+Z+ antigens labelled with I125, was precipitated by natural or immune anti-W antibodies. About 60 per cent of the W-Z+ 125I-labelled antigens were precipitated by immune anti-Z antibodies. No specific precipitation could be detected with W-Z- 125I-labelled antigens. All the precipitin reactions were quantitatively inhibited with the crude antigen extracts of the corresponding phenotypes. The W and Z antigens were only found in the intestinal mucosa and there was a 100-fold increase in the relative concentrations between the small bowel and the rectum. As opposed to this, the ABH antigens were found in all the digestive secretions studied, except those of the rectum, and their relative concentrations progressively decreased by about 100 between the small intestine and the recutm. The decrease in ABH concentration seems to be correlated to a WZ increase in the same regions.

ABO Blood-Group System↗
PubMed1977

Differences in the maturation of the immune response of A- and A+ rabbits. Good and poor responders respectively for the A antigen.

The amount, avidity and specificity of anti-A antibodies produced by rabbits having the A substance in their secretions (A+) and rabbits lacking this antigen (A-), were studied with a series of antigens chemically related to the A substance. Both A- and A+ rabbits produced specific anti-A antibodies but the amount, maturation of avidity and specificity of these antibodies was completely different. These results suggest that the difference between the immune response of A+ and A- animals is not based on a genetically determined inability of A+ rabbits to recognize the self antigen, but rather on differences in the regulatory mechanism(s) controlling the maturation process of the anti-A response.

Animals↗
PubMedDate not supplied

Palatability and intake relationships in free-living humans. characterization and independence of influence in North Americans.

In order to investigate palatability influences on the ad lib eating behavior of free-living humans, 564 participants were paid to maintain food intake diaries for 7 days. They recorded their intake along with a global rating of the palatability of the entire meal on a seven-point scale. It was found that most meals that are self-selected are palatable and that only 9.3% are rated as unpalatable. Meals that were highest in palatability were 44% larger than meals that were low in palatability, but palatability only accounted for around 4% of the variance in meal sizes. Multiple regression demonstrated that palatability appears to act on intake independent of the levels of other influential factors. These results were very similar to those observed for the French and suggest that palatability operates similarly on intake regardless of culture. Palatability appears to be an influence on the amounts ingested by free-living humans in their natural environments but appears to be only one of many influential factors and accounts for only a small proportion of the variance in intake.

Adolescent↗