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L M Stoolman

Publications and source records attributed to L M Stoolman.

44 records · Page 3Linked to original sources
PubMed1985

Flow cytometric analysis of DNA in diagnostic cytology.

Flow cytometric analysis of nuclear DNA content and cell surface immunologic phenotyping were used in the evaluation of cytologic samples obtained from four patients. In each sample, a lymphoid cell population was present, which was difficult to evaluate by traditional cytopathologic methods. In two of the cases, the flow cytometric demonstration of monoclonal populations of lymphoid cells characterized by abnormal amounts of nuclear DNA gave support to the cytologic interpretation of malignancy. In a third sample, a lymphoid cell population that could not be cytologically distinguished from malignant lymphoma cells of small lymphoid cell type was shown to be composed of euploid, polyclonal cells. In the fourth case, the demonstration of euploidy in morphologically distinctive cell populations was helpful in interpreting the fine-needle aspirate of the thyroid gland. The authors conclude that flow cytometry can be used to great advantage in the evaluation of cytologic samples as well as in predicting biologic behavior.

Adult↗
PubMed1984

Phosphomannosyl receptors may participate in the adhesive interaction between lymphocytes and high endothelial venules.

Normal and malignant lymphocytes can migrate from the bloodstream into lymph nodes and Peyer's patches. This process helps distribute normal lymphocytes throughout the lymphoid system and may provide a portal of entry for circulating malignant cells. An adhesive interaction between lymphocytes and the endothelium of postcapillary venules is the first step in the migratory process. We have recently shown that the simple sugars L-fucose and D-mannose, and an L-fucose-rich polysaccharide (fucoidin), can inhibit this adhesive interaction in vitro. We now report that mannose-6-phosphate, the structurally related sugar fructose-1-phosphate, and a phosphomannan, core polysaccharide from the yeast Hansenula holstii (PPME) are also potent inhibitors. Inhibitory activity was assessed by incubating freshly prepared suspensions of lymphocytes, containing the various additives, over air-dried, frozen sections of syngeneic lymph nodes at 7-10 degrees C. Sections were then evaluated in the light microscope for the binding of lymphocytes to postcapillary venules. Mannose-6-phosphate and fructose-1-phosphate were potent inhibitors of lymphocyte attachment (one-half maximal inhibition at 2-3 mM). Mannose-1-phosphate and fructose-6-phosphate had slight inhibitory activity, while glucose-1-phosphate, glucose-6-phosphate, galactose-1-phosphate, and galactose-6-phosphate had no significant activity (at 10 mM). In addition, the phosphomannan core polysaccharide was a potent inhibitor (one-half maximal inhibition at 10-20 micrograms/ml); dephosphorylation with alkaline phosphatase resulted in loss of its inhibitory activity. Preincubation of the lymphocytes, but not the lymph node frozen sections, with PPME resulted in persistent inhibition of binding. Neither the monosaccharides nor the polysaccharide suppressed protein synthesis nor decreased the viability of the lymphocytes. Furthermore, inhibitory activity did not correlate with an increase in negative charge on the lymphocyte surface (as measured by cellular electrophoresis). These data suggest that a carbohydrate-binding molecule on the lymphocyte surface, with specificity for mannose-phosphates and structurally related carbohydrates, may be involved in the adhesive interaction mediating lymphocyte recirculation.

Animals↗
PubMed1983

Time-dependent decreases in binding affinity of agonists for beta-adrenergic receptors of intact S49 lymphoma cells. A mechanism of desensitization.

Studies of beta-adrenergic receptors on several types of intact target cells indicate that agonists, but not antagonists, show prominent KD/Kact discrepancies--lower affinities (KD) in equilibrium binding studies (i.e. in competition with antagonist radioligands) than in functional assays (Kact). In this report we show that intact S49 lymphoma cells initially bind beta-adrenergic agonists in a high affinity manner but that this high affinity binding rapidly converts to a low affinity state. This time course is similar to that of agonist-mediated desensitization in S49 cells. In competitive binding studies conducted with [125I]iodocyanopindolol or [125I]iodohydroxybenzylpindolol, IC50 values for beta-adrenergic agonists increased 13-200-fold between 1 and 60 min, whereas antagonists yielded similar IC50 values at the two time points. The binding of antagonists, but not agonists, could be simulated by a computer model based on the law of mass action. In contrast with results in intact S49 cells, crude membrane fractions yielded similar IC50 values for agonists in 1- and 60-min incubations with [125I]iodocyanopindolol. Moreover, time-dependent decreases in apparent affinity of the agonist (-)-isoproterenol were observed not only in wild type S49 cells but also in several S49 variants (UNC, cyc-, H21a) having defects in Ns, the guanine nucleotide binding protein that couples receptors to activation of adenylate cyclase, and in Kin-, an S49 variant with absent cAMP-dependent protein kinase activity. These results show that beta-adrenergic receptors of intact S49 cells demonstrate a prominent time-dependent decrease in apparent affinity for agonists and that this decrease in affinity does not require cAMP generation, the Ns components defective in several S49 variants or cAMP-dependent protein kinase. The rapid conversion of agonist binding from high to low affinity can account for the rapid desensitization of intact cells to catecholamines and probably explains previously reported KD/Kact discrepancies of intact cells.

Animals↗
PubMed1983

Possible role for cell-surface carbohydrate-binding molecules in lymphocyte recirculation.

We are investigating the hypothesis that carbohydrate-binding molecules on the cell surface are involved in the recirculation of lymphocytes from the bloodstream into lymphoid organs. This phenomenon requires the specific attachment of circulating lymphocytes to the endothelial cells of postcapillary venules. Using an in vitro assay to measure the adhesive interaction between lymphocytes and postcapillary venules, we have found that L-fucose, D mannose, and the L-fucose-rich, sulfated polysaccharide fucoidin specifically inhibit this binding interaction. L-fucose shows stereo-selective inhibitory activity at concentrations greater than 18 mM while fucoidin produces 50% inhibition at approximately 1-5 X 10(-8) M. Fucoidin appears to interact with the lymphocyte, and not the postcapillary venule, to inhibit binding. These data suggest that cell surface carbohydrates (fucoselike) and carbohydrate-binding molecules (cell surface lectins) may contribute to the specific attachment of lymphocytes to postcapillary venules.

Agglutination↗
PubMedDate not supplied

Effects of tumor necrosis factor-alpha on the in vitro maturation of tumor-reactive effector T cells.

Culture methods that enhance the anti-tumor reactivity of primed T cells would be important in adoptive immunotherapy of cancer. Using several different syngeneic murine tumor models, the authors evaluated the effects of tumor necrosis factor-alpha (TNF-alpha) exposure on tumor-draining lymph node (TDLN) cells during in vitro activation. Mice were inoculated with weakly immunogenic (i.e., MCA 205, MCA 207 sarcoma) or the poorly immunogenic (i.e., D5 melanoma) tumor cells, and TDLN cells were harvested 9 or 10 days later for activation by an anti-CD3/interleukin-2 culture procedure. Human recombinant TNF-alpha (25 ng/mL) added during the activation culture resulted in a two-fold increase in interferon-gamma release (type 1 response) and a significant reduction of interleukin-10 (type 2 response) after tumor antigen stimulation. In an adoptive transfer model, TNF-alpha-cultured TDLN cells mediated significantly greater regression of established tumor than did TDLN cells cultured in the absence of TNF-alpha in five of five experiments. Neutralization of interleukin-10 monoclonal antibody further augmented the therapeutic efficacy of TNF-alpha-cultured TDLN cells. These studies document the ability of TNF-alpha to selectively promote a type 1 over a type 2 response in a bulk population of tumor-primed T cells during in vitro activation.

Animals↗
PubMedDate not supplied

Cytoimmunologic monitoring and heart transplantation.

Cytoimmunologic monitoring (CIM) combines morphological quantitation of activated lymphocytes and immunoblasts with immunophenotyping of peripheral blood in an effort to identify patients at risk for heart transplant rejection. In this study, CIM and endomyocardial biopsy (EMB) results were correlated in 55 paired blood and tissue specimens obtained from 18 heart transplant patients after operation. We found that 83% of patients with rejection and 81% of patients without rejection had increased levels of morphological activated lymphocytes. Multiple other criteria for determining levels of activation were used without improving the sensitivity or specificity. The use of CD4:CD8 ratios to discriminate between activation caused by rejection and those from viral infections and other inflammatory conditions yielded a sensitivity of 43% and specificity of 56%. The presence of activation markers such as I2, TAC, and T9 did not correlate with either CIM or EMB findings. CD4:CD8 alone was not predictive of cardiac rejection as increased, normal, and decreased CD4:CD8 ratios were seen in patients with and without rejection. Other measurements such as percentage of activated lymphocytes, total lymphocyte count, and whole blood cell count did not correlate with EMB or immunophenotypic findings. These results indicate that neither CIM, as currently conducted, nor immunophenotyping alone is sensitive or specific enough to substitute for EMB in screening for tissue rejection.

Antibodies, Monoclonal↗