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F Meloni

Publications and source records attributed to F Meloni.

123 records · Page 7Linked to original sources
PubMedDate not supplied

Proaggregating and procoagulant activities of human mesothelioma tumor cells at different stages of "in vitro" culture.

BACKGROUND: The mechanisms of the interactions between tumor cells and the hemostatic system are not completely understood; the purpose of this study was to elucidate whether tumor cells grown "in vitro" express the same proaggregating and procoagulant activities as cells isolated from tumor tissues, and whether the activities of such cultures are constant and consistent over time. METHODS: Tumor cells were collected and cultured from the pleural fluid of a 71-year-old patient with a sarcomatous malignant mesothelioma. Platelet aggregating activity was studied by adding tumor cells to platelet rich plasma or to washed, aequorin-loaded platelets. The procoagulant activity of the tumor cells was measured by the one-stage recalcification time of different humans plasma substrates. RESULTS: Cells harvested after 4 culture passages possessed low, ADP-dependent platelet aggregating activity, while those studied after 16 or 40 passages activated platelets through the production of thrombin. In the washed platelet system and in the presence of trace amounts of platelet poor plasma, the difference in the aggregating activity of various tumor cell populations was more evident. Normal mesothelial cells did not induce platelet aggregation. Procoagulant activity (tissue factor-like) was low in normal mesothelial cells and in tumor cells after 4 passages, and it was about 10 times higher in tumor cells after 16 or 40 passages. CONCLUSIONS: Results obtained with tumor cells cultured "in vitro" should be considered with caution because their effects are different from those of freshly isolated cells and may not be constant in the different culture passages.

Adult↗
PubMedDate not supplied

[The problem of the mandible in surgery of tonsillar tumors: proposal of a technique].

The Authors report a technique of a conservative transmandibular approach for the surgical treatment of tonsillar region malignancies. The procedure is based upon the preparation of a vascular mandibular flap through two osteotomies, which are performed, the first above the mandibular foramen and the second below the mental foramen. The main advantages of present technique are: lip-chin-splitting is avoided and, due to the preservation of mandibular vascular and nervous supply, it is possible to accomplish, without risk, postoperative radiotherapy. Moreover, if dictated by oncologic reasons, this conservative procedure may easily be transformed into a radical surgery (commando or neck-jaw operation).

Humans↗
PubMedDate not supplied

[Post-operative recurrence of naso-sinus polyposis].

Maxipolyposis, i.e. severe, diffuse nasosinusal polyposis, is generally treated with an onerous surgery. Therefore, recurrence, roughly rangling from 15% to 25%, are quite a disagreable outcome which is to be minimized. To this purpose, it may be useful to differentiate the residual from the recurrent polyposis, as is usually done in cases of cholesteatoma. Residual polyposis can be reduced by a thorough surgical resection. The authors detail their present technique, which joins microsurgery, used to perform ethmoidectomy, with endoscopic surgery, employed to manoeuvre within the sphenoid and maxillary sinus, as well as to drain the frontal sinus, i.e. to treat areas out of the direct view. Moreover, patients are warned of the need for close postoperative controls which should always be performed through telescopes in order to secure a sound inspection of the surgical cavities. Any slight, incipient recurrence should be immediately resected in the office by means of endoscopic technique. Recurrent polyposis must be treated with the drug therapies now in use, a waiting complete elucidation of the pathogenic mechanism. Association with systemic diseases, such as asthma, may contraindicate major surgery, as it increases the recurrence expectancy. Simple polypectomy often attains the same result in these cases, that is temporary ventilation of the nasal fossae.

Humans↗
PubMedDate not supplied

[Tumor necrosis factor alpha. Biological aspects].

Human Tumor Necrosis Factor-alpha (TNF-alpha) is a multifaceted cytokine mainly produced by activated monocytes or macrophages. Several recent studies have shown that TNF-alpha can exert a variety of in vitro and in vivo effects including: modulation of normal and malignant haemopoiesis, antineoplastic activity, activation of neutrophils, induction of IL-1 production, hyperpyrexia and induction of cachexia. Furthermore this cytokine is thought to play an important role in the pathogenesis of septic shock. The principal biochemical characteristics and biological activities of this cytokine will be here summarized.

Animals↗
PubMedDate not supplied

Human tumor cells cultured "in vitro" activate platelet function by producing ADP or thrombin.

We studied the effects on platelet function of different human tumour cells cultured "in vitro": Mo T lymphocyte cell line, NCI-N592 small cell lung carcinoma cell line, and 5637 bladder carcinoma cell line. Mo and NCI-N592 cells possessed a slight, dose-dependent platelet aggregating activity, which was completely abolished by apyrase and unaffected by hirudin. The cell-free supernatant also induced an aggregation response, which was very similar to that obtained with tumour cell suspensions. The presence of ADP in the cell-free supernatants of cell suspensions was confirmed by HPLC analysis. On the contrary, aggregation induced by 5637 cells was preceded by a significant lag phase; it was not affected by apyrase but it was abolished by hirudin, and the cell-free supernatant had no effect. These data suggest that Mo and NCI-N592 cells activate platelets by producing ADP, while 5637 cells stimulate platelet function by generating thrombin. The amount of ADP produced by the first two tumour cell lines was measured by bioassay: the extent of such production was similar for both cell lines and the maximum was reached after 60 minutes and maintained for up to 3 hours. These results suggest that neoplastic cells can activate platelets by different mechanisms: such investigations should be performed in homologous systems and in well-defined experimental conditions.

Adenosine Diphosphate↗
PubMedDate not supplied

Effect of interferon alpha, interferon gamma and tumor necrosis factor on the procoagulant activity of human cancer cells.

BACKGROUND: It is not known whether the different cytokines may influence the procoagulant activity of cancer cells; the purpose of this study was to investigate the effect of interferon alpha, interferon gamma and tumor necrosis factor on the procoagulation capacity of human cancer cells cultured "in vitro" or isolated from tumor tissues. METHODS: "In vitro" cultured tumor cell lines were derived from a patient with malignant mesothelioma and a patient with lung adenocarcinoma. Cells isolated from 6 carcinomas of different origin were also investigated. The procoagulant activity of the cells before and after treatment with the cytokines was expressed as RBT U/10(5) cells or RVV U/10(5) cells. RESULTS: Short-term incubation of tumor cells cultured "in vitro" with cytokines did not modify their procoagulant activity; after longer incubation however, interferon alpha induced a significant increase in the procoagulant activity of mesothelioma cells, while interferon gamma induced and increase in the procoagulant activity of lung adenocarcinoma cells. Furthermore, short-term incubation of cells isolated from tumor tissues with interferon gamma or tumor necrosis factor resulted in a significant increase of procoagulant activity, while interferon alpha had no effect. CONCLUSIONS: Altogether, these data demonstrate that the cytokines may influence the expression of the different procoagulant activities of tumor cells.

Blood Coagulation↗