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M T Nava

Publications and source records attributed to M T Nava.

5 recordsLinked to original sources
PubMed1985

Scanning immunoelectron microscopy of hairy cell leukemia.

Scanning electron microscopy has shown a typical cell surface morphology in hairy cell leukemia. Scanning immunoelectron microscope techniques, utilizing monoclonal antibodies and colloidal gold particles, have recently become available. Eight patients with hairy cell leukemia have been studied with a panel of monoclonal antibodies of which B1, BA1, OKM1, anti-TAC and LeuM5 were shown to be suitable for scanning immunoelectron microscopy and reactive with hairy cells. The combination of typical cell surface features with reactivity for the B1 and LeuM5 monoclonal antibodies permits accurate diagnosis of hairy cell leukemia, particularly when low percentages of hairy cells are present as in hypocellular or in interferon-treated patients.

Antibodies, Monoclonal↗
PubMed1985

Scanning electron microscope cytochemistry of blood cells.

The backscattered electron imaging (BEI) mode of scanning electron microscopy (SEM) has been applied to study various histo-cytochemical reactions in biological specimens since the early seventies. Due to numerous, recent technical improvements the BEI mode of SEM now belongs to the routine of many SEM laboratories. For cytochemistry, BEI has been mainly used to: visualize intracellular structures and organelles; recognize the different cell types in heterogeneous populations or tissues; study the correlations between enzymatic activities and cell surface features. We have evaluated the most relevant results obtained in the study of blood cells and the possible future applications of these techniques.

Blood Cells↗
PubMed1983

Cytochemical methods for the backscattered electron imaging mode of scanning electron microscopy: further applications to the study of human leukemic cells.

The Backscattered Electron Imaging (BEI) mode of Scanning Electron Microscopy (SEM) has been applied to the study of cells stained with various heavy metals in cytochemical reactions. Improvements or modifications of some of these methods and their application to the study of normal and leukemic leukocytes have been evaluated in this report. The results obtained after staining peroxidase-positive granules with osmium, copper, cobalt-nickel and gold-cobalt are compared. Granules containing non-specific esterase activity were demonstrated in the BEI mode after incubation of the cells in Hanker medium and staining with osmium. While sites of acid phosphatase activity were easily localized with a conventional lead method, alkaline phosphatase activity was demonstrated only in the phagocytic vacuoles of cells previously incubated with latex particles and subsequently stained with lead. Cell nuclei were identified in the BEI mode after silver methenamine or bismuth staining. Combining their cell surface and cytochemical characteristics a more accurate identification of the different blood cell types with the SEM becomes possible.

Acid Phosphatase↗
PubMed1979

Ultrastructural study of leukemic cell phagocytosis using the myeloperoxidase reaction.

The phagocytosis (in the absence of serum factors) of zymosan particles by peripheral leukocytes isolated from ten patients with acute leukemia (AMbL, AMoL, AMML, AUL, ALL and CML-BC) was studied at the electron microscope. An evident phagocytic activity was observed only in the cells in which cytochemical and ultrastructural features suggested that the blast elements belonged to the monocytic series. However, no phagocytosis by unclassifiable leukemic blasts was observed, even though they had some submicroscopic characteristics of the monocytic series. These findings suggest that phagocytic capacity develops during the course of cell differentiation, becoming striking only when the blast cell acquires the ultrastructural features of the pro-monocytic stage. Using the myeloperoxidase reaction, this study also demonstrates a morphological alteration in the degranulation process after the ingestion of zymosan particles in both the blasts and the mature PMN cells of leukemic patients. This defect could be related to the susceptibility to severe infections usually found in subjects with hematological malignancies.

Humans↗