Localisation of myocardial ischaemia from the magnetocardiogram using current density reconstruction method: computer simulation study

A computer simulation study is performed to investigate the method of current density reconstruction to localise myocardial ischaemia. A computer model of the entire human heart is used to simulate the excitation and repolarisation process in eight topographically different cases of myocardial ischaemia. The associated magnetocardiogram is calculated at 37 positions of the KRENIKON^* biomagnetic measurement equipment. The method of current density reconstruction is applied at the S-point (the last discemible deviation from the ST-segment at the end of the QRS-complex) of the MCG to find characteristics of the myocardial ischaemia simulated by the model. The results show that it is possible to determine the location of the ischaemia. The current density distribution may be interpreted physiologically in terms of the so-called ‘injury current’. This indicates that magnetocardiography might be a suitable method for noninvasive ischaemia diagnosis, and further investigations of the current density reconstruction method for the injury current should be performed on patients with ischaemic heart disease.     

Successful nonsibling bone marrow transplantation in severe combined immunodeficiency.

Severe combined immunodeficiency (SCID) was diagnosed in a girl immediately after birth; her older brother had SCID and was successfully reconstituted by bone marrow transplantation from his uncle. She was isolated in a laminar air flow bench and decontaminated. The father differed by one HLA-A antigen but was HLA-Dw2 homozygous like the patient; his lymphocytes showed a slight response to the patient's cells in mixed lymphocyte culture (MLC). At the age of 2 1/2 months and again at 5 months, she was given a bone marrow transplant from the father. During the entire course the patient had no infections, and apart from a transient eosinophilia she had no signs of graft-versus-host reaction. Immunological reconstitution was nearly complete at 9 months of age, when she was recontaminated. One year later plasma immunoglobulin concentrations are in the low normal range (IgG and IgM) or decreased (IgA); tests of cell-mediated immunity are normal. Apart from slight upper respiratory infections, the patient has been healthy. Physical and psychological development have been normal.     

Intracellular Lysozyme in Mature Neutrophils and Blast Cells in Acute Leukemia

Intracellular lysozyme (muramidase) activity was measured in leukemic blastsand mature neutrophilic granulocytes from20 patients with acute myeloblastic andmyelomonocytic leukemia and in 11 patients with acute lymphoblastic leukemiaafter differential centrifugation of cellsin Ficoll and extraction of lysozyme withn-butanol. Considerable abnormalities incellular lysozyme activity were found bothin qualitative and quantitative terms. Incontrast to normal myeloblasts, leukemicblasts of the myeloid series containedlysozyme in a considerable number ofcases. Although no clear-cut distinctionwas seen, those patients with positiveblast lysozyme reactivity tended to havethe highest plasma lysozyme levels,whereas no good correlation was foundbetween morphologic differentiationalong myeloblastic or monocytoblasticlines of blasts and lysozyme reactivity.Calculations of the magnitude of lysozymeproduction in acute leukemias with highplasma lysozyme concentration was compatible with the hypothesis that in thesecases lysozyme must be secreted by intactblasts and that, consequently, plasmalysozyme activity reflects the total leukemic cell mass. In mature neutrophilicgranulocytes from patients with acutemyeloblastic and myelomonocytic leukemia in relapse, the mean lysozyme activity was significantly decreased, although a great deal of variation wasfound. In remission, neutrophil lysozymeactivity seemed to increase; among several possibilities this might be a reflectionof different clones being operative in relapse and remission. In acute lymphoblastic leukemia, lysozyme activity inneutrophils was constantly low in relapseand increased to normal following induction of remission, which may be themain explanation of the low plasmalysozyme activity found in this type ofacute leukemia. It is unexplained andpuzzling why intraneutrophil lysozymeactivity is low in a leukemic type wherethe myeloid cells are not believed to beprimarily leukemic; one possible reasonmight be an effect of cell-to-cell interaction with the leukemic cell population.

Submitted on November 30, 1973 Revised on February 19, 1974 Accepted on February 20, 1974     

A monoclonal antibody (NAT-9 II:3F-6F) that identifies a differentiation antigen on human myeloid cells

A monoclonal antibody, designated NAT-9 II:3F-6F (IgM), was generated by hybridization of mouse myeloma cells with spleen cell from mice immunized with normal human bone marrow cells. The antibody reacted with 40-60% of bone marrow cells as analysed on samples from 40 normal individuals and only with a subpopulation of human acute myeloid leukemia (AML) cells of the M2 class (20/20 tested) and M4 class (12/12 tested) (subclasses of the French-American-British (FAB) classification), but not with leukemic cells of the M1 (0/12 tested) and M5 (0/12 tested) FAB subclasses. This is in contrast to many other myeloid-specific monoclonal antibodies. Fluorescence-activated cell sorter (FACS) analyses and morphological examination of cells stained with peroxidase as based on the NAT-9 II:3F-6F monoclonal antibody showed that this antibody reacted with a distant differentiation antigen which is absent on myeloblasts, but expressed on promyelocytes, myelocytes, metamyelocytes, band neutrophils, and on a minority of mature granulocytes. NAT-9 II:3F-6F did not bind to circulating monocytes, T and B cells, erythrocytes and a variety of different human cell culture lines. Immunoblotting demonstrated that the antibody bind to a cellular component with a Mr approximately 97.400 dalton. The antibody may be useful in immunological subclassification of non-lymphoid leukemias and in studies on hematopoiesis.     

Lösungs- und verdünnungswärmen von polyethylenglykolen in wasser und benzol, 1. Experimentelle ergebnisse

Dissolution and dilution enthalpies of poly(ethylene glycol)s were measured in water and benzene, resp., by microcalorimetry. The enthalpies depend on both solute concentration and molar mass, indicating interactions between hydroxyl endgroups, ether groups and solvent molecules. Low molar mass samples form hydrogen bonds between hydroxyl and ether groups at solute concentrations of 0,003 g/cm³ and higher. High molar mass samples form intermolecular associates through dispersion forces at concentrations above 0,06 (benzene) and 0,1 g/cm³ (water).