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Biomedical subjects

M M Ricetti

Publications and source records attributed to M M Ricetti.

27 records · Page 2Linked to original sources
PubMed1983

Interactions between tumor cells and vascular endothelium.-II) Light and electron microscopic studies.

Electron microscope technique was used to investigate the passage across the endothelial monolayer by murine tumor lines. After the initial adhesion, cancer cells induce a retraction of endothelium and migrate under vascular intima. Subsequently they spread on basement membrane showing a flattened shape, meanwhile endothelial cells reconstitute the monolayer. The four tumor lines show a similar behaviour being able to induce endothelial retraction and exposure of extracellular matrix and cross through the monolayer. The technique appears useful to study in details this multi-step process.

Animals↗
PubMed1983

Interactions between neoplastic cells with different metastasizing capacity and platelet function.

We have examined the effects on platelet function of two sublines (M4 and M9) derived from spontaneous lung nodules of a benzopyrene-induced murine fibrosarcoma (m FS6). The subline M4 was more metastatic and the subline M9 less metastatic than the primary tumour. Only the more malignant cells were able to induce irreversible aggregation of human platelets; this effect was concentration-dependent and was associated with the release of serotonin by platelets. Both aggregation and release were inhibited by preincubation of platelets with ASA, not by preincubation of the cells. The supernatants of cell suspensions had no aggregating activity. However, the neoplastic cells in culture media released an activity directly stimulating platelet aggregation and potentiating the platelet response to ADP; again, this activity was higher for the more malignant cells and the effects were inhibited by preincubation of platelets with ASA. These results suggest a role for platelets in the development of tumour metastases.

Adenosine Diphosphate↗
PubMedDate not supplied

Selenium enhances glutathione peroxidase activity and prostacyclin release in cultured human endothelial cells. Concurrent effects on mRNA levels.

Selenium (Se) is an essential component of glutathione peroxidase (GSH-Px), an enzyme that protects cells by reducing intracellular peroxides. Impaired Se status and GSH-Px activity seem associated with increased risk of atherosclerotic vascular diseases. This study reports the effects of Se supplementation on GSH-Px activity, on prostacyclin (PGI2) production, on 12-hydroxy-eicosatetraenoic acid (12-HETE) levels, and on GSH-Px mRNA expression in cultured human umbilical vein endothelial cells (HUVEC). Se-enriched HUVEC showed significant increase of both GSH-Px activity and thrombin-stimulated production of PGI2 in the presence of stable concentrations of 12-HETE. On the other hand, an inverse correlation between Se concentrations in culture media and GSH-Px mRNA levels in Northern blot analysis was shown; this suggests that a major degree of regulation for GSH-Px expression by Se is most likely exerted at the posttranscriptional level. These observations may help to explain the increased incidence of atherosclerosis described in Se-deficient individuals.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMedDate not supplied

Improved prognosis of Pseudomonas aeruginosa bacteremia in 127 consecutive neutropenic patients with hematologic malignancies.

OBJECTIVES: Although decreasing in frequency, Pseudomonas aeruginosa bacteremia is still a major challenge for neutropenic cancer patients. In patients with hematologic malignancies, the prognosis of P. aeruginosa bacteremia is particularly poor due to the prolonged and severe neutropenia, mucosal damage, and other defects in immunity related both to the underlying disease and to the cytotoxic therapy. METHODS: To verify the outcome of P. aeruginosa bacteremia and to try to define possible prognostic factors, the authors reviewed the medical records of 127 consecutive episodes of P. aeruginosa bacteremia observed in the hematologic unit of the Verona University School of Medicine. RESULTS: Presence of pneumonia and septic shock, persistence and severity of neutropenia, delayed and inappropriate antibiotic therapy, and unresponsive underlying disease had negative impact on clinical outcome of P. aeruginosa bacteremia. CONCLUSIONS: With recognition of the risk factors and more careful management, the prognosis of P. aeruginosa bacteremia in neutropenic patients with hematologic malignancies has improved in recent years.

Adolescent↗
PubMedDate not supplied

Preferential release of high amounts of interleukin-8 by myeloid blasts showing monocytic differentiation.

BACKGROUND: In myeloid blasts, the expression and release of the multifunctional chemokine IL-8 could be expected to be differentiation-associated. METHODS: We investigated the profile of interleukin-8 (IL-8) expression and release by leukemic cells obtained at diagnosis from 42 untreated adult patients with acute myeloid leukemia of various FAB subtypes (2 M0, 7 M1, 6 M2, 6 M3, 10 M4 and 11 M5). IL-8 transcripts were evaluated by Northern blot and densitometric analysis. IL-8 release by myeloid blasts was evaluated by a specific ELISA either in sera at diagnosis or in supernatants (SN) obtained from cultured leukemic cells. RESULTS: In basal conditions, Northern blot analysis revealed detectable IL-8 transcripts in 15/29 cases, eleven of which were classified as M4-M5 and 4 as FAB M0-M3. Densitometric analysis of IL-8 transcript bands showed higher expression in M4-M5 than in M0-M3 cases (mean values +/- SD: 16.5 +/- 21 and 0.77 +/- 1.36 densitometric units, respectively; p = 0.012). Higher IL-8 serum levels were observed in leukemic patients as opposed to normal controls (mean values +/- SD: 0.53 +/- 0.75 vs 0.003 +/- 0.014 ng/mL, respectively; p = 0.006). Furthermore, a trend (though not of statistical significance) towards higher IL-8 serum values was observed in M4-M5 as opposed to M0-M3 subtypes. After 24 hours of culture, the majority of myeloid blasts (95%) spontaneously released detectable amounts of IL-8 into SN. However, M4-M5 released substantially higher amounts of IL-8 than M0-M3 blasts (mean +/- SD: 68 +/- 46 and 8.5 +/- 12 ng/mL, respectively; p < 0.001). This difference between M0-M3 and M4-M5 blasts was already observed after 6 hours of culture and increased over 72 hours. CONCLUSIONS: Our findings confirm and further support the preferential release of high levels of IL-8 by myeloid blasts showing monocytic differentiation.

Acute Disease↗