No abstract

The utilization of tannic acid and guanidine hydrochloride as mordants for better osmium binding has been shown to serve as an excellent alternative to metal coating of organ tissue specimens for scanning electron microscopy (SEM). The present report describes the G T G O procedure, a modification of the TAO technique introduced by Murakami er al. (1977, 1978), which we have found successful for the Preparation of air dried peripheral blood leucocytes for SEM studies. Air dried, GTGO-treated leucocytes show excellent preservation of surface features with minimal cell shrinkage. When critical point dried, GTGO-treated cells are examined, they also show less shrinkage than cells prepared with standard glutaraldehyde fixation and critical point drying. T h e potential application of this air drying procedure (GTGO-AD) to other soft biological specimens is currently under investigation. This technique is recommended as a new and effective air drying procedure for the successful Preparation of cells for SEM.

A new cell line, HD-Mar, was established from a pleural effusion of a patient with Hodgkin's lymphoma. Formation of E rosettes, sensitivity to anti-T serum, elevated terminal deoxynucleotidyl transferase activity, presence of T-cell and the common ALL membrane antigens, morphology, and cytochemical staining indicate that the HD-Mar line is of thymic derivation. Absence of any immunoglobulin determinants, the lack of EBNA or any other EBV-associated antigen or function are also characteristics associated with established T-cell-derived lymphoma cell lines. Karyotype analysis indicated a tetraploid origin of the cell line.

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In the light of recent observations reporting that B-lymphocytic leukemia (B-CLL) cells may express a variety of myelomonocytic antigens, 28 patients with B-CLL and B-leukemic lymphocytic lymphoma were studied for the presence of these antigens using monoclonal antibodies to detect CD13, CD33, CD15 and CD14. Analysis of immunofluorescence (IF) was carried out by two procedures; one which employed the standard conventional method of gating used in our laboratory for flow cytometry, while the other procedure increased the sensitivity of the analysis, by moving the marker for IF to the left, so as to widen the gate to include more cells with low IF. Using the conventional methodology, the mean proportion of cells considered positive was less than 3% for any of the 4 markers studied. In only a few patients were 5% or more of the B-CLL cells positive for some of the markers studied (3 patients with 6.2-11.3% CD13+; 2 with 6.0-9.6% CD14+, and one with 11.8% CD15+ cells). No case had more than 2.5% + CD33+ cells. The second procedure with a wider gate to enhance sensitivity for less positive cells, increased the number of positive cells for any of the markers in only 4 patients. These results are contradictory to others reported recently, and some of the possible causes for this discrepancy are discussed. It is suggested that more useful data may be obtained if the level of staining intensity and patterns of positive staining are documented in the future.