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Biomedical subjects

D Guerry

Publications and source records attributed to D Guerry.

At least 91 records · Page 5Linked to original sources
PubMed1979

Human monocyte-lymphocyte interaction and its enhancement by levamisole.

We investigated the role of monocyte-lymphocyte interaction in the transformation of human peripheral blood lymphocytes by the mitogen concanavalin A (Con A). Human monocytes were separated from lymphocytes and were transiently exposed to Con A. The Con A-pretreated monocytes were able to subsequently bind autologus lymphocytes by a process that was selective for T cells. This interaction required the initial presence of Con A at the monocyte surface, and became independent of surface bound ligand after 72 hr. Levamisole, an agent thought to facilitate the participation of monocytes in the cellular immune response, enhanced the binding of lymphocytes to monocytes at low concentration of Con A (5--10 micrograms/ml). Levamisole did not lead to mitogen independent lymphocyte binding. The association between lymphocytes and Con A-pretreated monocytes resulted in the mitogenic transformation of lymphocytes in the absence of soluble Con A in the medium. These results suggest that, in addition to any possible soluble mediators, direct lymphocyte-monocyte contact is required for optimal mitogenic transformation. This T-cell-monocyte interaction over time becomes independent of cell-surface mitogen. The ability of levamisole to enhance this interaction may explain levamisole's capacity to stimulate lymphocyte proliferation.

Adult↗
PubMed1978

Dural arteriovenous fistula and spontaneous choroidal detachment: new cause of an old disease.

A case is presented in which bilateral spontaneous choroidal detachments appear to be the direce result of bilateral dural arteriovenous fistula of the cavernous sinus region. Rapid resolution of the clinical signs followed bilateral orbital decompression via the transfrontal approach. Similarities in clinical presentation of both entities are reviewed and a premise for their cause-and-effect relationship elaborated. A literature search for similar unrecognised cases is discussed. The paper suggests that this association may be more frequent than published reports would imply.

Aged↗
PubMed1977

A randomized clinical trial of granulocyte transfusions for infection in acute leukemia.

In a prospective, controlled, randomized study to evaluate the efficacy of filtration-leukapheresis granulocytes in granulocytopenic, febrile patients with leukemia, 19 patients received antibiotics alone, and 12 received antibiotics plus daily granulocyte transfusions from ABO-matched donors. In skin-chamber studies the granulocytes appeared at sites of inflammation for at least six hours after transfusion. Infected subjects survived longer if they received granulocytes. Differences between control and transfused patients were greatest in patients with persistent bone-marrow failure, the 21-day survival being 20 per cent in controls, and 75 per cent in transfused patients. Granulocytes appeared to have no effect on the outcome of febrile episodes in which infection was not documented, the 21-day survival being 79 per cent for controls and 88 per cent for transfused patients. The transfusion of granulocytes thus appears to offer a survival advantage to infected, persistently granulocytopenic patients.

Acute Disease↗
PubMed1977

Effect of cytochalasin B on human monocyte binding and sphering of IgG-coated human erythrocytes.

The ability of human mononuclear phagocytic cells to bind IgG-coated human erythrocytes (EA) and to cause bound EA to become osmotically fragile (sphered) was investigated in the presence of cytochalasin B, a known inhibitor of phagocytosis. Cytochalasin B inhibited the binding of EA to mononuclear cells in a dose-dependent fashion; 80% inhibition of binding was observed at a concentration of 5 mug/ml. This profound effect on EA binding together with presently available data suggested a role for IgG receptor mobility in the macrophage binding of IgG-coated erythrocytes. Cytochalasin B, however, had a minimal effect on the capacity of mononuclear cells to sphere adherent EA, suggesting that the processes involved in macrophage-induced spherocytosis may differ from those operable in phagocytosis.

Cell Adhesion↗
PubMed1976

Concanavalin A-mediated binding and sphering of human red blood cells by homologous monocytes.

Human red blood cells sensitized with concanavalin A became bound to homologous peripheral blood monocytes. Binding occured at a concentration of 10(5) molecules of tetrameric Con A per red blood cell (RBC) and increased with additional Con A. RBC binding began within 5 min and was maximal at 90 min. Phagocytosis of sensitized RBCs was minimal. RBC attachment was prevented by 0.01 M alpha-methyl-D-mannopyranoside, and, once the RBC-monocyte rosette was established, bound RBCs were largely removed with this specific saccharide inhibitor of Con A. RBCs attached to monocytes became spherocytic and osmotically fragile. The recognition of concanavalin A (Con A)-coated RBCs was not mediated through the monocyte IgG-Fc receptor. These studies demonstrate that, like IgG and C3b, Con A is capable of mediating the binding of human RBCs to human monocytes. Red cells so bound are damaged at the monocyte surface.

Binding Sites↗
PubMed1973

Periodic hematopoiesis in human cyclic neutropenia.

Human cyclic neutropenia is characterized by severe depression of blood neutrophil levels approximately every 21 days. To investigate the mechanism of cyclic neutropenia four patients were studied with daily complete blood counts, serial bone marrow examinations, marrow reserve testing, serum muramidase determinations, DF(22)P granulocytokinetic studies, and, in one patient, in vivo [(3)H]TdR labeling. Periodogram analysis of the serial blood counts in the latter patient and visual inspection of multiple cycles in the others revealed periodic fluctuations in the levels of blood neutrophils, monocytes, lymphocytes, reticulocytes, and platelets. Rhythmic changes in the morphologic and radioisotopic studies as well as the marrow reserve tests and muramidase measurements were consonant with a mechanism of periodic failure of marrow production rather than peripheral destruction. Human cyclic neutropenia is analogous to cyclic neutropenia in the grey collie dog and may be viewed as the consequence of cyclic hematopoiesis.

Agranulocytosis↗