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M L Scott

Publications and source records attributed to M L Scott.

171 records · Page 10Linked to original sources
PubMedDate not supplied

Effect of blood group active micro-organisms on the ABO grouping of human whole saliva.

Three saliva samples with false positive ABO grouping results were assayed for blood group active organisms, using a variety of selective media to isolate representative strains from the salivary microflora. Eight out of 40, 8 out of 40 and 4 out of 30 strains from the three samples, respectively, showed blood group activity, which correlated well with the false positive specificities of the saliva samples. In all cases the false reaction only lasted a few days. Investigation of one of these samples before and after the appearance of the false positive activity yielded only one out of 40 blood group active organisms, using the same methods. Similar investigation of two "normal" saliva samples found none out of 40 and one out of 40 blood group active organisms, respectively. It is concluded that occasional false positive ABO grouping reactions of saliva samples are probably caused by the presence of unusually high numbers of blood group active micro-organisms, due to disturbances in the ecological balance of the salivary microflora.

ABO Blood-Group System↗
PubMedDate not supplied

Standardization of papain reagents by measurement of active sites using a synthetic inhibitor, E-64.

L-trans-epoxysuccinyl-leucylamido (4-guanidino) butane (E-64) reacts rapidly and irreversibly in a one-to-one ratio with the active site of papain, causing complete inhibition of the enzyme. After the addition of various concentrations of E-64 to a papain preparation, the residual enzyme activity can be measured using an azoprotein technique. The molarity of E-64 required to cause complete inhibition of papain activity is equal to the molarity of papain-active sites. Preparations of papain from various sources were assayed for protease activity by hydrolysis of azoalbumin using several variants of the basic technique and also by hydrolysis of azocasein. For each variant of azoprotein assay procedure, the active sites of the papain were measured using E-64. All variations of the azoprotein technique yielded similar estimates of the active site molarity of the papain preparations, whereas the azoprotein assay results alone showed wide variation. Quantitation of the active-site molarity of various papain preparations using E-64 correlated with serologic efficacy.

Azo Compounds↗
PubMedDate not supplied

Analysis of the structure and activity of A and A,B immunoglobulin A monoclonal antibodies.

A study of the serologic activity and molecular structures of three spleen-derived mouse IgA monoclonal human blood group-specific supernatants was undertaken; this was part of an evaluation of these monoclonals as blood typing reagents. The monoclonal antibodies were eluted through a precalibrated size-exclusion column, and fractions were analyzed by immunoblotting, heavy and light chain-specific enzyme-linked immunosorbent assay, and liquid- and solid-phase serologic tests. Results indicated that one of the supernatants (anti-A specificity) contained tetrameric and monomeric forms of IgA, while the other two (anti-A,B specificity) contained three higher polymeric forms (1000-4000 kDa) and one dimeric form. The tetrameric and polymeric forms showed red cell agglutinating activity, whereas the dimeric and monomeric forms did not. All forms contained heavy and light chains. The monomeric anti-A showed specific binding to appropriate red cells in a solid-phase assay, but the dimeric anti-A,B fractions did not. Purified fractions stored at 4 degrees C did not show any equilibration toward other forms, which indicated that the molecules are stable once secreted. The use of such antibodies as blood grouping reagents requires careful monitoring to ensure that high proportions of nonagglutinating molecular weight forms are not produced, as they could compromise the performance of the reagent by binding to red cell antigen in competition with the agglutinating forms.

ABO Blood-Group System↗
PubMedDate not supplied

Cold agglutinin activity is common among human monoclonal IgM Rh system antibodies using the V4-34 heavy chain variable gene segment.

BACKGROUND: The V4-34 gene segment is commonly used by human monoclonal IgM alloantibodies against blood group antigens and by cold-reactive red cell autoantibodies with anti-I or anti-i specificity. This study was conducted to determine whether cold agglutinin activity is found among the V4-34-encoded alloantibodies. STUDY DESIGN AND METHODS: Fifty-four human IgM monoclonal antibodies (MoAbs) against Rh system antigens were tested for cold agglutinin activity against red cells lacking the relevant Rh system antigen and for reactivity with tissue I and/or i antigens using immunohistochemistry. The findings were correlated with the utilization of the V4-34 segment as determined in an enzyme-linked immunosorbent assay with an antibody (9G4) that is specific for this gene product and were also correlated with other serologic properties. RESULTS: Of the MoAbs, 59 percent were 9G4-positive. Of the 9G4-positive subset, 16 and 44 percent agglutinated native adult (express I) and cord (express i) cells, respectively, at 4 degrees C; these levels rose to 84 and 94 percent, respectively, with the use of papain-treated cells. The red cell antigens recognized at 4 degrees C were cleaved by endo-beta-galactosidase, which is consistent with their being I and i. Of the 9G4-positive subset, 53 percent bound to tissue i antigen. These reactivities were not found among 9G4-negative MoAbs. Endo-beta-galactosidase treatment of red cells enhanced Rh system antibody agglutination by 9G4-negative MoAbs. CONCLUSION: Anti-I/i reactivity is common among IgM Rh system MoAbs and is shown only by the V4-34-encoded subset. This finding has implications for the use of MoAbs for Rh system typing of blood.

Agglutinins↗
PubMedDate not supplied

Bypass to anterior descending coronary artery in patients with aneurysm or scarring of left ventricle.

Fifteen cases who have had myocardial infarction with aneurysm formation or severe scarring of the left ventricle as a result of occlusion of left anterior descending coronary artery are presented. Bypass to left anterior descending coronary artery using internal mammary artery or saphenous vein was done in all of these patients. Ten of these had plication or excision of the left ventricular aneurysm. All of them survived the operation and are doing well. Early results in this series of patients indicate that left anterior descending coronary artery bypass in these patients is of great value by allowing perfusion to patent brances of left anterior descending coronary artery.

Adult↗