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C Crespi

Publications and source records attributed to C Crespi.

59 records · Page 4Linked to original sources
PubMedDate not supplied

Role of target and effector cell structures in natural killer-mediated cytotoxicity.

An analysis of target and effector cell structures involved in the in vitro natural killer (NK)-mediated cytotoxicity has been performed. The degree of surface expression of transferrin receptor (TR) was only in part correlated with that of cell lysis. Moreover, the lysis could not be blocked by treating target cells with two anti-TR monoclonal antibodies. Finally, cell lines poorly affected by NK cells express TR only at the cytoplasmic level. As to the effector cells, the integrity of cytoskeleton components (especially microtubules) was found to be essential for the occurrence of cell lysis. In fact, vinblastine, an anti-microtubule agent, was able to significantly reduce the percentage cell lysis. This effect was not due to a selective depletion in NK cells induced by the drug. It is concluded that the mechanisms underlying NK activity are complex and involve both target and effector cell structures.

Cell Line↗
PubMedDate not supplied

A simple method for purification of human monocytes and evaluation of IgG Fc-receptor-mediated phagocytosis.

A simple and reproducible, although not completely original method for purification of human monocytes and evaluation of IgG Fc-receptor-mediated phagocytosis has been set up and is described here. The purity of monocyte preparations obtained by the use of this method is quite elevated (over 95%), but the yield, although satisfactory for this purpose, is rather poor. As to the test of phagocytosis, a time-response curve using opsonized sheep erythrocytes showed that 10-min incubation gives the best and most reproducible results. A peroxidase reaction is suggested in order to obtain a better evaluation of erythrocytes within monocytes. The test has been proved suitable for evaluation of Fc-receptor function of monocytes in primary biliary cirrhosis, an immunological liver disease, and might be also useful in immune complexes-mediated conditions.

Adult↗
PubMedDate not supplied

Relationships between smooth muscle and cytoskeleton antibodies in human serum samples.

In order to characterize the relationship between smooth muscle antibodies (SMA) and antibodies directed to the cytoskeleton components (microfilaments, intermediate filaments and microtubules), 338 serum samples from patients with various diseases and from healthy control subjects were tested for SMA and anti-cytoskeleton antibodies using a conventional immunofluorescence method employing traditional substrates and vinblastine-treated fibroblasts. The correspondence between SMA and these antibodies turned out to be incomplete and more evident for anti-microfilaments and anti-microtubules than for anti-intermediate filaments antibodies. Our data confirm that SMA are a quite heterogeneous family of antibodies, whose specificities are not entirely related to the cytoskeleton components. Studies with purified antigens will probably characterize these specificities.

Antibodies↗
PubMedDate not supplied

Thyroid hormone and thyrotropin regulate intracellular free calcium concentrations in human polymorphonuclear leukocytes: in vivo and in vitro studies.

Intracellular free calcium concentrations (Ca++i) were studied in polymorphonuclear leukocytes (PMNs) from 13 athyreotic patients who had been previously treated by total thyroidectomy and radioiodine therapy for differentiated thyroid carcinoma, and from age- and sex-matched euthyroid healthy controls. Patients were studied twice, when hypothyroid (visit 1) and after restoration of euthyroidism by L-T4 TSH-suppressive therapy (visit 2). PMNs from patients at visit 1 had significantly lower resting (Ca++)i levels compared to both visit 2 and controls. Values at visit 2 did not differ from those of the controls. Stimulus-induced (Ca++)i rise was also significantly blunted at visit 1 and normalized at visit 2, possibly through a differential contribution of distinct intracellular Ca++ stores, as suggested by the response pattern to the chemotactic agent, N-formyl-Met-Leu-Phe (fMLP), to the selective SERCA pump inhibitor, thapsigargine, and to the mitochondrial uncoupler, carbonyl cyanide p-trifluoromethoxyphenyl-hydrazone (FCCP). In vitro treatment of PMNs from healthy subjects with high TSH concentrations impaired intracellular Ca++ store function. Both resting (Ca++)i levels and fMLP-induced (Ca++)i rise increased in the presence either of low-concentration TSH or of T4, but effects of TSH and T4 were not additive. T3, rT3, and TRIAC had no effect. In conclusion, this study provides evidence for a direct relationship between thyroid status and (Ca++)i homeostasis in human PMNs, mainly related to direct actions of TSH and T4 on these cells.

Adult↗