Biomedical subjects

A M Luciani

Publications and source records attributed to A M Luciani.

22 records · Page 2Linked to original sources

PubMed1990

Soluble CD8 antigen in systemic sclerosis.

In 15 patients suffering from systemic sclerosis (PSS) the function of CD8+ circulating lymphocytes was assayed by determining soluble CD8 antigen (sCD8) both in sera and in 48 hr PHA-conditioned media of peripheral blood mononuclear cells (PBMCs). Furthermore, the frequency of circulating activated CD8+ cells, which express DR antigens, interleukin-2 receptor, and transferrin-receptor, was determined by cytofluorographic analysis. The results of this preliminary study indicate that only in 6 PSS sera sCD8 was elevated as compared to healthy controls; furthermore, we found slightly increased sCD8 in culture media from PSS patients. The frequency of circulating activated CD8+ cells was similar both in PSS patients and in controls. Overall, our findings suggest that CD8+ cell activation is not a major phenomenon in PSS.

Adult↗

PubMed1989

Biochemical and NMR studies on structure and release conditions of RNA-containing vesicles shed by human colon adenocarcinoma cells.

Large amounts of particulate material, mostly lipid vesicles, are released by human colon adenocarcinoma HCT-8R cells when they are packed at high density in saline solution. RNA is also present in the released structures. Vesicle sheding is displayed only by healthy and viable cells. The process, in our experimental conditions, lasts up to 40 min, and can be restored by supplementing cells with nutrients and oxygen. RNA and lipids give rise to IH and 3IP NMR signals. The process is somehow related to a thermotropic transition observed by means of IH NMR spectroscopy for peculiar lipid domains in the plasma membrane. Analysis of 3IP NMR spectra of the phosphodiester groups, upon pH variation, indicates strong interaction between RNA and proteins in an assembled structure. A constant amount of polyA+ RNA can be recovered from the vesicles. The electrophoretic pattern and in vitro protein synthesis indicate that mRNA can be isolated as a functionally active molecule with a major 5 Kb fraction.

Adenocarcinoma↗

PubMed1989

Characterization of vesicles, containing an acylated oligopeptide, released by human colon adenocarcinoma cells. NMR and biochemical studies.

RNA-containing vesicles, recovered from the supernatant of high-density cell samples of human colon carcinoma, produce a high-resolution 1H NMR spectrum of lipids characterized by isotropic tumbling; these vesicles contain large amounts of triglycerides and cholesterol esters. Both findings have strict analogies to what is displayed by the proteolipid complexes isolated from the sera of tumor-bearing patients [(1985) Proc. Natl. Acad. Sci. USA 82, 3455-3459; (1986) FEBS Lett. 203, 164-168]. Lipid analysis and enzymatic tests indicate that these vesicles are selected micromaps of plasma membranes, analogous to those that can be recovered from culture media in which tumor cells are grown [(1985) Dev. Biol. 3, 33-57]. Peculiar lipids, an acylated oligopeptide and a modified phospholipid, are also present in the vesicles.

Acylation↗

PubMed1988

RNA-lipid complexes released from the plasma membrane of human colon carcinoma cells.

Cultured cells from human colon adenocarcinoma spontaneously release structures which display an intense 31P NMR signal from RNA and mobile phospholipids. Furthermore, the DPH probe in the cell supernatant shows an intense fluorescence, thus indicating its insertion in lipid vesicles. The total membranes, prepared from the same cells, also release similar structures. The fatty acid chain signals from the mobile lipids, observable in the H NMR spectrum, and the fluorescence polarization of the DPH probe are strongly affected by RNAase digestion, thus indicating an association between RNA molecules and lipids. The enzymatic marker cytochrome c reductase was assayed to rule out possible contamination from endoplasmatic reticulum. A high alkaline phosphatase activity was instead found in the supernatant samples, thus indicating that the shed material is released by the plasma membrane.

Adenocarcinoma↗