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Biomedical subjects

D Y Mason

Publications and source records attributed to D Y Mason.

321 records · Page 18Linked to original sources
PubMed1975

Effect of human lysozyme (muramidase) on potassium handling by the perfused rat kidney. A mechanism for renal damage in human monocytic leukaemia.

Purified human lysozyme (muramidase) stimulated potassium excretion by the isolated perfused rat kidney. Lysozyme is filtered and reabsorbed, without a tubular maximum. Over 90% of lysozyme filtered is retained within the kidney; 50% was recovered by enzymic assay and histologically localized to the proximal tubular cells. Hypokalaemia seen in some patients with myelomonocytic leukaemia may be directly attributed to an elevated circulating lysozyme level.

Animals↗
PubMed1970

Sensitivity of platelets to aspirin in von Willebrand's disease.

The sensitivity of collagen-induced platelet aggregation to aspirin was measured in vitro on platelet-rich plasma from 20 normal subjects and five patients with von Willebrand's disease. Although aspirin tolerance tests performed in vivo at the same time showed an abnormal prolongation of the bleeding time in three of the patients studied, no evidence was found for an enhanced sensitivity to aspirin in vitro.

Aspirin↗
PubMedDate not supplied

Evidence for the detection of the normal counterpart of Hodgkin and Sternberg-Reed cells.

To clarify the origin of Hodgkin (H) and Sternberg-Reed (SR) cells, frozen sections of lymph nodes from 30 patients with Hodgkin's disease were immunostained with a large panel of monoclonal antibodies reactive with cells of lymphoid tissue and granulopoiesis. The results showed that: (a) H and SR cells are devoid of markers specific to, or characteristic of B cells, macrophages, dendritic reticulum cells, interdigitating cells, or cells of erythropoietic or thrombopoietic origin; (b) the vast majority of H and SR cells contain granulocyte-related antigens detectable with the monoclonal antibodies TU9 and 3C4, but constantly lack other granulocytic cell markers (such as peroxidase and chloroacetate esterase). Monoclonal antibodies raised against a Hodgkin's disease-derived cell line included one, Ki-1, that was found to be selectively reactive with H and SR cells and a minute, but distinct cell population in normal lymphoid tissue and bone marrow. The latter, as yet unidentified cell population appears to be the normal equivalent of H and SR cells.

Animals↗
PubMedDate not supplied

In situ immunologic characterization of follicular lymphomas.

Surface markers were studied in a series of follicular lymphomas with immunofluorescence on frozen sections (39 cases) and on cell suspensions (21 cases), and with immunoperoxidase on frozen sections using a panel of 15 monoclonal antibodies (17 cases). With immunofluorescence on frozen sections, 22/39 cases showed monotypic sIg (IgMK: 14 cases, IgML: 7 cases, M: 1 case). In the remaining 17 cases the neoplastic follicles were negative. Nevertheless, even if sIg is not detected, the absence of an extracellular immunoglobulin network is indicative of the neoplastic, and not of the reactive nature of lymphoid follicles. The results obtained with immunofluorescence on frozen sections and on cell suspensions were identical in about half of the cases. In 9/21 cases monotypic sIg were detected by only one of these two methods. All the 17 cases studied with immunoperoxidase on frozen sections using monoclonal antibodies demonstrated monotypic sIg. On low magnification 6/17 sIg+ exhibited a nodular staining pattern while 7/17 cases this staining was diffuse. In 4/17 cases the staining pattern for heavy and light chains was different. A thin mantle zone, with sIgM plus sIgD cells, was observed in only 4 cases. Anti-HLA-DR and Leu-10 were positive in all cases. T cells positive for OKT3 were mainly distributed in the interfollicular areas; OKT4+ cells outnumbered OKT8+ cells. Within the neoplastic follicles, T cells stained mainly for OKT4 and OKT8+ cells were scarce. Leu-7+ cells predominated within the neoplastic nodules in 5 cases. With the anti-dendritic reticulum cell monoclonal antibody, all 17 cases showed a network, usually more loosely arranged than in reactive follicles. In 4 cases, of follicular and diffuse lymphoma, this network was extremely dissociated and in some areas these cells were scanty or lacking. We concluded that immunoperoxidase on frozen sections, using monoclonal antibodies, appears to be the most reliable method for the immunological phenotyping of follicular lymphomas.

Antibodies, Monoclonal↗
PubMedDate not supplied

Morphological and phenotypic features in pediatric large cell lymphoma and their correlation with ALK expression and the t(2;5)(p23;q35) translocation.

Anaplastic large cell lymphoma (ALCL) was proposed as a clinicopathologic entity over 14 years ago, but has been somewhat controversial due to the variability of its defining features and variable occurrence in different age-groups. To evaluate this entity in a pediatric population, 36 cases of childhood large cell lymphoma were evaluated for abnormalities of the anaplastic lymphoma kinase (ALK) gene that has been associated with ALCL morphology and immunophenotype. ALK abnormalities were evaluated by assay for the t(2;5)(p23;q35) translocation by RT-PCR and/or expression of NPM-ALK fusion protein by immunohistochemistry. Results showed 17 patients to have evidence of ALK gene expression. All of these children (mean age, 9.3 years) had tumors that were of T-cell phenotype (with the exception of a single case of null phenotype) and that expressed CD30. In contrast, 19 children with no evidence of ALK expression were older (mean, 12.7 years), and the majority (12/19) had tumors of B-cell phenotype. CD30 was also diffusely expressed in 8 of these 19 tumors. The difference in mean age between the two groups was statistically significant (P = 0.015). In three cases tested for both ALK and the t(2;5), ALK protein was detected in the absence of the t(2;5) translocation but no cases showed the reverse pattern, consistent with ALK fusion to genes other than NPM or activation of the ALK gene by another mechanism. These findings provide further support that ALK-positive ALCL is a distinct pathologic entity among pediatric large cell lymphomas primarily characterized by expression of T-cell markers, CD30, and EMA, and by a younger mean age.

Adolescent↗
PubMedDate not supplied

An immunoelectron microscopic study of human placenta using three monoclonal antibodies.

An immunoelectron microscopic technique was used to analyse the distribution in term human placentae at the ultrastructural level of three antigens recognized by recently developed monoclonal antibodies. Two of the antigens (recognized by NDOG-1 and NDOG-2) were present only on the outer villous membrane of the syncytiotrophoblast. The other (HLA-A, B, C) was absent from syncytiotrophoblast and present on some capillary endothelial cells and on Hofbauer cells in the villous stroma.

Antibodies, Monoclonal↗
PubMedDate not supplied

Transferrin receptor on endothelium of brain capillaries.

The blood/brain barrier prevents the passive diffusion of proteins and metabolites from cerebral blood vessels into tissue spaces around neuronal and glial cells. To provide nutrients for these cells, transport mechanisms must exist and indeed have been demonstrated for metabolites. We now show that monoclonal antibodies against rat and human transferrin receptors label blood capillaries in the brain but not in other tissues. In the rat this labelling occurs after injection of antibody into the blood, thus the receptors seem to be accessible at the endothelial surface. It is possible that transferrin receptors are expressed on these cells to allow transport of transferrin (and thus iron) into brain tissues.

Animals↗