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N Semeraro

Publications and source records attributed to N Semeraro.

At least 55 records · Page 3Linked to original sources
PubMed1988

Aggregation of human peripheral blood mononuclear cells by calcium ionophore A23187. Comparison with the aggregation of platelets and defective response in Glanzmann's thrombasthenia.

Following exposure to calcium ionophore A23187, washed peripheral blood mononuclear cells (MNC) aggregated and formed thromboxane, like platelets. However, while aspirin strongly inhibited platelet aggregation and thromboxane formation, it had a little effect on the aggregation of MNC. In about 50% of the samples studied, aggregation of MNC was associated with the secretion of ATP. However studies in which exogenous ATP or ADP were used, suggested that the aggregation of MNC is independent of the secretion of nucleotides. MNC from 2 thrombasthenic patients failed to aggregate and bound 9-10 fold less radiolabelled fibrinogen than those from normals when challenged with A23187. However, fibrinogen, which plays a major role in the aggregation of platelets, did not appear to be involved in the aggregation of MNC. A differing behavior of these two types of cells was also found when the effect of plasma was studied on the aggregation response to A23187. Indeed, citrated plasma greatly enhanced the aggregation of platelets while it suppressed the response to MNC. This inhibitory effect of plasma was not detected when heparinized plasma was substituted for citrated plasma. We conclude that the aggregation of MNC in response to A23187 does not involve basic events known to play a major role in the aggregation of platelets. The response to A23187 may be an important probe for understanding basic mechanisms and pathophysiological significance of the aggregation of MNC.

Adult↗
PubMed1988

Procoagulant activity of mouse transformed cells: different expression in freshly isolated or cultured cells.

This study was originally designed to investigate whether there is any correlation between the type of procoagulant activity (PCA) and the tumorigenicity of transformed cells. The data obtained are relevant to this question and to defining the differences in the expression of cellular activities depending on the in vitro system used. PCA was measured and characterized in normal, immortalized, and tumorigenic mouse fibroblasts. In all the cell lines studied the activity was of tissue factor type, as established with functional, enzymatic, and immunochemical criteria. However, the PCA of cells freshly isolated from the tumors induced by tumorigenic cell lines was of cancer procoagulant type, i.e. a cysteine protease with direct factor X activator activity. The same cells, when cultured in vitro, expressed again PCA of tissue-factor type. These results suggest that either a tumor-host interaction is required for the expression of cancer procoagulant or the latter activity, produced by tumor cells under in vitro conditions, is destroyed or inactivated during the culture period. Our findings caution against defining the procoagulant activity of tumors based on experiments on cultured cells.

Animals↗
PubMed1988

Treatment with cyclosporin A does not affect macrophage procoagulant activity and plasminogen activator inhibitor in mice.

Using a mouse model, we have investigated the in vivo effect of cyclosporin on macrophage procoagulant activity and on plasma levels of plasminogen activator inhibitor. Procoagulant activity of peritoneal macrophages was studied after treatment of mice with different regimens of cyclosporin (10 to 100 mg/kg body weight) for seven days. No significant difference was found between treated and control animals in both basal procoagulant activity and procoagulant activity generated during short-term culture in the absence or in the presence of endotoxin. These findings are in striking contrast with in vitro experiments showing that cyclosporin induced a significant increase in procoagulant activity when added to peritoneal macrophages from normal animals before challenge with endotoxin (p less than 0.01). Plasma levels of plasminogen activator inhibitor in cyclosporin-treated mice were not different from those of controls. It is suggested that factors other than monocyte-macrophage procoagulant activity or plasminogen activator inhibitor may be important for the postulated 'prothrombotic' action of cyclosporin.

Animals↗
PubMed1988

Different expression of procoagulant activity in macrophages associated with experimental and human tumors.

Mononuclear phagocytes, an integral part of the lymphoreticular infiltrate of human and experimental tumors, might contribute to fibrin deposition within malignant tissues through the production of procoagulant activity (PCA). Recent studies in different types of experimental tumors and in some cancer patients indicate that the functional status in terms of PCA of mononuclear phagocytes at 'peripheral' sites is not the same as that of macrophages at the tumor site (tumor-associated macrophages, TAM). Peripheral blood monocytes and/or peritoneal macrophages from V2-carcinoma-bearing rabbits and from mice bearing different types of tumors, like cells from normal animals, have low levels of basal PCA and are able to respond with a marked increase in PCA to in vitro stimulation. Likewise, in patients with primary lung cancer, pulmonary alveolar macrophages (PAM) obtained from the contralateral side of the neoplasm and blood monocytes behave essentially as cells from normal individuals. In contrast, profound changes in PCA have been found in TAM. In some experimental tumors and in a number of the patients, macrophages taken at the tumor site express high levels of basal PCA, which most probably reflect in vivo activation. Local activation of macrophages for PCA production might contribute to fibrin deposition at the tumor site. In the other experimental tumors studied and in the remaining patients, not only have macrophages low basal PCA but they also fail to respond to various stimulants in vitro. Although the mechanisms underlying these changes and their pathophysiological significance remain to be established, it is apparent that neoplastic growth may modulate the expression of macrophage PCA at the tumor site.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Induction of monocyte-macrophage procoagulant activity by transformed cell lines.

Human peripheral blood monocytes and mature macrophages were found to produce significant procoagulant activity (PCA), identified as tissue factor, on exposure to a variety of human (K562, HL60, Raji) and murine (TU5, NS-1) transformed cell lines. The monocyte procoagulant response was vigorous, generating PCA to a level nearly comparable to the response to endotoxin, a known stimulant for monocyte PCA. The response was rapid and could be fully elicited, in a dose-dependent fashion, within 4 hr with HL60 and Raji cell lines and within 14 hr with K562, TU5, and NS-1 cells. The monocyte PCA-inducing activity was found to reside in the membrane fraction of transformed cells. Other transformed human (Laz 509, Laz 221, Laz 156, U937, CEM) and murine (L1210, P815, TLX9, WEHI 164) cell lines had little, if any, activity. The induction of monocyte PCA by transformed cells most probably was not due to an allogeneic signal, as 1) the K562 and HL60 cell lines were potent PCA inducers despite the lack of class II histocompatibility antigen expression, whereas Laz 156, which did express HLA antigens, was ineffective; 2) mouse peritoneal macrophages responded with the production of strong PCA to the syngeneic transformed cell lines TU5 and NS-1. The monocyte-macrophage procoagulant response to transformed cell lines appeared to be independent of T lymphocytes. Indeed, monocytes purified on the basis of reactivity with monoclonal antibody Mo2 and sorting or depleted of contaminating T cells by anti-T3 antibody and complement responded similarly to conventional monocyte preparations. The production of tissue factor by monocyte-macrophages in response to exposure to some tumor cells may represent a mechanism whereby blood coagulation is activated in malignancy.

Animals↗
PubMed1986

Procoagulant activity of human alveolar macrophages: different expression in patients with lung cancer.

Mononuclear phagocytes, an integral part of the lymphoreticular infiltrate of many malignant tissues, might contribute to tumor-associated fibrin deposition through the production of procoagulant activity (PCA). We have studied the PCA of human alveolar macrophages in 28 patients with primary lung cancer and in 9 control subjects. Alveolar macrophages (greater than 97% esterase positive) were isolated form bronchoalveolar lavage fluids by adherence onto plastic. PCA was evaluated by a one-stage clotting assay immediately after isolation (basal PCA) and after incubation (4 hr at 37 degrees C) in the absence and in the presence of endotoxin. Cells from control subjects had low basal PCA (3.9 +/- 1.0 units/5 X 10(4) cells) but, upon exposure to endotoxin, they displayed a 5- to 16-fold increase in PCA. In patients, different patterns of PCA were observed. In the 8 patients in whom lavage had been carried out on the contralateral side to the neoplasm, alveolar macrophages behaved essentially like those from controls. In contrast, in the 20 patients in whom macrophage populations close to the site of the tumor were examined, PCA was abnormal in many respects. In 12 of these, alveolar macrophages had basal PCA comparable to or somewhat lower than control cells, but exhibited a poor procoagulant response when incubated in vitro in the presence of endotoxin. Alveolar macrophages from the remaining 8 patients expressed far higher levels of basal PCA than control cells (25.1 +/- 5.9 units as compared to 3.9 +/- 1.0 units/5 X 10(4) cells). These cells retained their ability to respond to endotoxin in vitro with a 3-fold increase in PCA. In all instances, alveolar macrophage PCA had the characteristics of tissue factor. These data suggest that the presence of primary lung cancer may modulate the expression of PCA in alveolar macrophages close to the tumor site. PCA might be useful to better characterize the functional state of macrophages near the tumor.

Adult↗
PubMed1986

Vitamin E and vitamin C inhibit arachidonate-induced aggregation of human peripheral blood leukocytes in vitro.

Arachidonate induces aggregation of human polymorphonuclear (PMN) and mononuclear (MNL) blood leukocytes. This is mediated by the lipoxygenase pathway, as it is prevented by lipoxygenase inhibitors and can also be induced by leukotriene B4 (LTB4). Vitamin E and vitamin C have profound effects on the functional state of leukocytes, some of which may involve the lipoxygenase pathway. This study shows that both vitamins inhibit arachidonate-induced aggregation of PMN and MNL, in a concentration-dependent way. BW-755, previously shown to inhibit arachidonate-induced PMN and NML aggregation, was found to potentiate the inhibitory activity of both vitamins. When LTB4 was used as an aggregating agent, vitamin E markedly inhibited PMN and MNL aggregation, whereas vitamin C was ineffective. The prevention of PMN and MNL aggregation by vitamin E might account, at least partially, for the reported beneficial effects of vitamin E supplementation in some experimental syndromes characterized by leukocyte activation.

Arachidonic Acid↗
PubMed1986

Generation of procoagulant activity by hairy cells in response to endotoxin and phorbol esters.

Several investigators have suggested that hairy cells are neoplastic B lymphocytes. These cells, however, also share some biological properties with mononuclear phagocytes. A property of these cells is the capacity to generate procoagulant activity (PCA) in response to a variety of stimuli. In this study we investigated the PCA of peripheral blood hairy cells in 19 consecutive patients with hairy cell leukaemia (HCL). Monocyte-depleted blood mononuclear cells, tested immediately after isolation, expressed little, if any, activity. However, after exposure to endotoxin, a marked increase in PCA was observed (42.1 +/- 8.7 vs 1.3 +/- 0.2 units/5 X 10(1) hairy cells). A significant correlation was found between the number of lymphocytes/hairy cell and the level of endotoxin-induced PCA suggesting that lymphocytes potentiate the procoagulant response of hairy cells. When stimulated with 12-0-tetradecanoyl-phorbol-13-acetate (TPA), patients' cells produced about 2-8 times more PCA than endotoxin-stimulated cells. The PCA induced by endotoxin and TPA was identified as tissue factor. These findings suggest some further relationship between hairy cells and monocytes.

Adult↗
PubMed1986

Increased monocyte procoagulant activity (tissue factor) in patients with essential mixed cryoglobulinemia.

Procoagulant activity (PCA) of peripheral blood mononuclear cells was studied in vitro in 14 consecutive patients with essential mixed cryoglobulinemia (EMC). Mononuclear cells tested immediately after isolation expressed significantly higher PCA than cells from a matched control group (P less than 0.01). PCA generated by patients' cells after incubation at 37 degrees C for four hours without any stimulant was significantly higher than that produced by control cells (P less than 0.001). Lower mononuclear cell PCA was observed in the subgroup of patients treated with low doses of prednisone than in untreated patients. In two patients given high-dosage prednisone, cell PCA was markedly reduced. These findings suggest that mononuclear cells may be activated for PCA production in vivo by cryoglobulins or other unknown stimuli. Mononuclear phagocytes, by producing PCA in vivo, might be directly implicated in the local fibrin deposition in tissue lesions of EMC.

Adult↗
PubMed1986

Vitamin K-dependent procoagulant in cancer cells: a potential target for the antimetastatic effect of warfarin?

Anticoagulants of the coumarin type have long been reported to inhibit metastasis growth in experimental animals; however, the mechanisms of such effects has not been clarified. Systemic anticoagulation per se does not appear to account completely for such metastasis growth depression. More recent information gathered on a cell procoagulant activity, which is vitamin K-dependent, could probably supply a fresh insight into this problem. Indeed, vitamin K deficiency induced either dietarily or pharmacologically by warfarin, does inhibit the activity of a cysteine protease with direct factor-X-activating properties. This protease is only present in warfarin-sensitive tumors. The correlation of this activity with cancer cell invasiveness is supported by experimental data in metastatic variants and, lately, also by the observation of markedly higher cancer procoagulant activity in extracts from metastases than from primary human melanomas.

Animals↗
PubMed1986

Cancer procoagulant in human tumor cells: evidence from melanoma patients.

It has repeatedly been proposed that fibrin plays a role in tumor growth and metastasis. Among tumor cell products or activities which may promote clot formation, cancer procoagulant (CP), a direct activator of coagulation factor X, has been suggested to be selectively associated with the malignant phenotype. We report here the enzymatic and immunological identification of this cysteine proteinase procoagulant in extracts and cells from human melanoma. CP activity was independent of both the intrinsic and extrinsic pathways of blood coagulation, using factor IX and factor VII deficient plasmas, and was inhibited by the cysteine proteinase inhibitors iodoacetamide and HgCl2. CP activity was detectable in extracts and cell suspensions from all 32 patients studied and was higher in extracts from metastases (14.8 +/- 3.9 units/mg protein) than from the primary tumors (3.7 +/- 1.0 units/mg protein). CP activity was not affected by an anti-apoprotein III antibody or by concanavalin A, a known inhibitor of thromboplastin. In contrast, no CP activity or antigen was detected in extracts from six benign melanocytic lesions. The procoagulant activity was dependent on factor VII and was inhibited by anti-apoprotein III antibody and by concanavalin A, properties that suggest that the procoagulant was tissue thromboplastin. These data indicate that CP can be expressed by human tumor cells and that, among melanotic lesions, its presence is associated with the malignant phenotype and its activity is particularly high in metastatic cells.

Adolescent↗
PubMed1985

Procoagulant activity of mouse and human cultured cells following various types of transformation.

The presence of fibrin deposits in the microenvironment of tumor cells has been reported repeatedly and considered to play an important role in tumor biology. Among the mechanisms by which fibrin may be deposited in tumors, procoagulant activities (PCA) of different types have been described in cancer cells. The present study was aimed at establishing whether the nature of cellular PCA was a characteristic associated with malignant transformation. PCA of normal and transformed cells was investigated on pairs of murine and human origin. The transformed counterparts were obtained after treatment with low-dose radiation, chemical carcinogen, viral infection or after in vitro spontaneous immortalization. Both before and after any type of transformation cell PCA was of the tissue thromboplastin type, identified on the basis of biological criteria: requirement of factor VII for its expression and lack of inhibition by the serine protease inhibitor diisopropylfluorophosphate (DFP). Transformed cells of murine origin showed significantly lower activity than their normal counterparts, whereas all the transformed human cell lines expressed significantly higher activity than normal. An inverse correlation between the levels of PCA and the cell density in culture was observed in all but one of the lines tested. These findings suggest that the factor X activating property described in some tumors or in transformed cells cannot be considered as a general marker of transformation.

Animals↗
PubMed1985

Failure to warfarin to affect the tissue factor activity and the metastatic potential of murine fibrosarcoma cells.

Vitamin K deficiency, either dietary or pharmacologically induced by warfarin, was unable to affect the metastatic capacity of cells from a benzopyrene-induced fibrosarcoma in C57BL/6J mice. The same cells had a procoagulant activity, of tissue thromboplastin type, which was also completely unaffected by vitamin K antagonism or deficiency. In another murine model of spontaneous metastasis we previously suggested that depression of a particular procoagulant such as a direct factor X activator might contribute to the antimetastatic activity of warfarin. The failure of vitamin K deficiency to affect both the procoagulant and the metastatic capacity of the model reported here offers strong negative support to the same concept.

Animals↗
PubMed1985

Production of interleukin 1 but not of procoagulant activity by large granular lymphocytes.

Large granular lymphocytes (LGL) share phenotypic and functional properties with monocytes. We have investigated the production of procoagulant activity (PCA), so far attributed to cells of the monocyte-macrophage lineage, by LGL. Endotoxin triggered interleukin (IL-1) release and PCA activity by highly purified monocyte preparations. In contrast, LGL exposed to endotoxin produced IL-1 but had no PCA activity. Similarly ineffective in inducing PCA in LGL were other stimuli that either triggered monocyte PCA or stimulated the natural killer cytotoxicity of LGL. Thus, although LGL share properties with monocytes such as the capacity to produce IL-1, PCA is confined, among circulating leukocytes, to cells of the monocyte lineage.

Antibodies, Monoclonal↗
PubMed1985

Increased in vitro and in vivo generation of procoagulant activity (tissue factor) by mononuclear phagocytes after intralipid infusion in rabbits.

Intralipid, a fat emulsion widely used in parenteral nutrition, can produce marked functional changes of the mononuclear phagocyte system. We investigated the effect of Intralipid administration on the generation of procoagulant activity by rabbit mononuclear phagocytes. Two groups of ten rabbits given either a single infusion of Intralipid 10% or a similar volume of sterile saline were studied before and after infusion. Procoagulant activity was measured on isolated blood mononuclear cells after incubation with and without endotoxin, using a one-stage clotting assay. Cells from animals infused with Intralipid produced significantly more procoagulant activity than controls (P less than .01). Results were similar when freshly collected whole blood was incubated with and without endotoxin, and procoagulant activity was measured on subsequently isolated mononuclear cells (P less than .01). In addition, when rabbits were given a single injection of endotoxin, blood and spleen mononuclear cells harvested 50 to 60 minutes after the injection from animals pretreated with Intralipid expressed five to seven times more procoagulant activity than did cells from animals pretreated with saline. In all instances, procoagulant activity was identified as tissue factor. These findings suggest that Intralipid may cause functional changes in mononuclear phagocytes, resulting in increased production of tissue factor on incubation in short-term culture in vitro and in response to endotoxin in vivo.

Animals↗