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S Miscia

Publications and source records attributed to S Miscia.

49 records · Page 3Linked to original sources
PubMed1989

Influence of phosphatidylcholine on two protein mRNA levels in interferon treated Daudi cells.

Evidence related to nuclear structure and metabolism have shown the presence of a chromatin lipid fraction which may be involved in the events of cell proliferation and differentiation (Maraldi et al., 1984, Cocco et al., 1987). The relative amounts of these molecules have been reported to be modified in different metabolic conditions of normal and neoplastic cells (Coetzee et al., 1975; Manzoli et al., 1982). Phospholipids have also been found among the components of the nuclear matrix where they seem to play a role in the interactions between nucleic acids and proteins (Berezney, 1984; Cocco et al., 1987). In this paper we report that the transcriptional induction of two genes (pIFN-IND-1 and pIFN-IND-2) produced by interferon in Daudi lymphoma cells is influenced by addition, in the transcriptional assay, of phosphatidylcholine (PC) liposomes which have been reported to be able to enter nuclei (Maraldi et al., 1984; Maraldi et al., 1982).

Cell Line↗
PubMed1988

Evidence for a reduction of the replicative activity of matrix-bound DNA polymerase alpha following treatment with phospholipase C.

Since phospholipids have been suggested to play some role in the molecular organisation of the nuclear matrix, the effect of their removal by means of phospholipase C has been investigated in regenerating rat liver nuclear matrix. The matrix-bound DNA polymerase alpha shows an almost complete loss of activity following the digestion with phospholipase C. Since the polymerase activity is restored by adding exogenous DNA, we suggest that the effect is due to the removal of matrix residual DNA, which is in some way linked to the nuclear matrix by means of hydrophobic interactions.

Animals↗
PubMed1987

Phospholipids as components of the nuclear matrix: their possible biological significance.

The phospholipid involvement in the regulation of the functional and structural properties of the nuclear matrix is discussed analysing the results obtained with the enzymic removal of these molecules. Namely phospholipids seem to mediate hydrophobic interactions between nucleic acids and matrix fibrils either directly or indirectly through an association with the non-histone proteins of the matrix.

Animals↗
PubMed1987

The application of flow cytometry to the study of nuclear matrix. A multiparametric analysis.

The nuclear matrix, which in situ corresponds essentially to the interchromatin ribonucleoprotein particles, once isolated appears constituted by a peripheral lamina connected to the nucleolar remnant by a fibrous network. The features of the matrix components depend on the procedure employed during its purification, a multistep method commonly involving nuclease digestion, low and high salt extractions and treatment with a non ionic detergent. Here is reported the application of flow cytometry to the analysis of matrix purification. The experimental data indicate that, despite deep changes of the nuclear content due to the selective extraction of almost all nucleohistone and membrane components, the scatter pattern of the matrix, which is drastically lowered as the nucleic acid content decreases, closely resembles that of the starting nuclei. This behaviour permits one to follow the different matrix populations deriving from diploid and polyploid parenchymal liver nuclei throughout the isolation procedure and confirms the feasibility of flow cytometry for both analysis and sorting of nuclei and nuclear matrices. In addition, an ultrastructural analysis on thin sections and a morphometric study by means of semiautomated image analysis of phase contrast micrographs have been performed. The image analysis showed a decrease in particle dimension to about 50% of the nuclear value, which could partially explain the reduction of forward light scatter.

Animals↗
PubMed1981

[Karyotype in chronic myeloid leukemia in a blastic crisis. II. Trisomy 17].

One case of a patient with Chronic Granulocytic Leukemia showing a double Ph' together with trisomy 17 during blastic crisis is reported. The Ph' chromosome resulting from a standard translocation of the chromosomes 9 and 22 was present in all the 16 mitoses observed, while the trisomy 17 was found in 15. This case is an additional contribution which demonstrates the presence of the alterations of the chromosome group E during the blastic crisis.

Chromosomes, Human, 16-18↗
PubMed1981

Effect of phospholipid vesicles on endogenous RNA polymerase activity of isolated rat liver nuclei.

Negatively charged phosphatidylserine vesicles increase RNA polymerase activity of isolated rat liver nuclei, whereas inhibition is obtained with sphingomyelin, phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol vesicles. The effect of phosphatidylserine on template activity is dose-dependent and similar to that reported for acidic polymers like heparin. These data indicate that the nature of the polar head is mainly responsible for the different effects and suggest that the phospholipids may be involved in mediating gene expression.

Animals↗
PubMed1981

Interactions among DNA, metallic ions, and lipids.

Interactions amond DNA, phospholipids, and Cu2+ ions have been investigated by means of thermal denaturation technique. The results indicate that phosphatidylserine and sphingomyelin interact with Cu2+ ions, which are able to prevent the chance of binding of the phospholipids to the double helix. This interaction is strictly dependent upon the concentration of the divalent cation and reduces the capability of the employed phospholipids to modify the thermal stability of DNA.

Chemical Phenomena↗
PubMed1980

[Karyologic analysis in erythroleukemia].

We report the cytogenetic data of two patients with erythroleukemia showing the chromosome Ph'. In one case the chromosome Ph', as revealed with the GTG band technique was the result of a translocation involving the chromosomes 19 and 22. The aim of this work is to provide more contribution to the knowledge of the origin of the Ph' and to give data in the field of this disease for which few cytogenetic data are available after the introduction of the banding techniques.

Aged↗
PubMedDate not supplied

Novel shift of Jak/Stat signalling characterizes the protective effect of aurintricarboxylic acid (ATA) from tumor necrosis factor-alpha toxicity in human B lymphocytes.

Previous results demonstrated that the occurrence of death in human peripheral B lymphocytes by TNF-alpha was paralleled by the activation of the cytoplasmic Jak1 and Tyk2 protein kinases, along with the recruitment of transcription factors Stat3 and Stat5b. In this study we demonstrate that the balance of survival signals in the presence of TNF-alpha was altered by the addition of a salicylate compound, the endonuclease inhibitor aurintricarboxylic acid (ATA). Apoptosis effected by TNF-alpha alone was suppressed by ATA and this event was paralleled by phosphorylation and nuclear translocation of Jak2, Stat2, Stat4 and NF-kB, along with inhibition of caspase activation. These results confirm that among the different cellular responses evoked by TNF-alpha in human B cells, recruitment of Jak/Stat proteins and possible related gene modulation represent contributing factors and address the issue of the development of potential therapeutic strategies aimed at the control of systemic or local effects produced by TNF-alpha.

Aurintricarboxylic Acid↗
PubMedDate not supplied

Novel evidence of PLC delta2 involvement in the regulation of the differential evolution of human aneurysms.

The biological and molecular mechanisms which are responsible for the formation and possible evolution of human aneurysms are unknown. Previous investigations have pointed to the possible involvement of inositol specific-phospholipase C (PLC) in the mechanisms related to the formation or evolution of intracranial aneurysms, but, thus far, a relationship of one or more PLC isoforms with the biological signals influencing the fate of this lesion has not been demonstrated. The aim of this study was to investigate the expression, activity and possible modification of PLC isoforms in intracranial aneurysms in patients undergoing elective surgical repair after casual identification of unruptured aneurysms, or during emergency surgical repair of ruptured aneurysms. PLC and proliferating cell nuclear antigen (PCNA) expressions were detected by immunohistochemical analysis; PLC activity was obtained by measuring its hydrolytic activity on labelled PIP(2); PKC activity was measured by total kinase activity assay. Results indicated no substantial differences between controls and aneurysms, with the only exception being PLC delta2 which was nearly absent in controls and ruptured aneurysms, while strongly expressed and functionally active in almost all unruptured aneurysms. In addition, its expression always correlated with the proliferation cell marker PCNA, while its specific activity always correlated to PKC activity. PLC delta2 distribution, regulation and role in human tissues are still unknown Therefore, although preliminary, these data provide a novel insight into the signalling machinery influencing the aneurismal progression.

Adult↗
PubMedDate not supplied

Nuclear protein kinase C-delta: a possible check-point of cell cycle progression.

Protein kinase Cs (PKCs) belong to a serine/threonine kinase family, ubiquitously expressed and claimed to be involved in physiological processes including apoptosis, cell growth and differentiation. The question of the subcellular localization and activity of PKCs remains to be clarified. Here we report that nuclear PKC-delta cooperates to regulate the S-G2/M phase transition of cell cycle, apparently being associated to chromosome condensation and alignment on the metaphase plate.

Cell Cycle↗
PubMedDate not supplied

Engagement of DNA polymerases during apoptosis.

DNA replicative and repair machinery was investigated by means of different techniques, including in vitro nuclear enzymatic assays, immunoelectron microscopy and confocal microscopy, in apoptotic cell lines such as HL-60 treated with methotrexate, P815 and K562 exposed to low temperatures and Friend cells exposed to ionizing radiation. The results showed a shift of DNA polymerase alpha and beta activities. DNA polymerase alpha, which in controls was found to be the principal replicative enzyme driving DNA synthesis, underwent, upon apoptosis, a large decrease of its activity being replaced by DNA polymerase beta which is believed to be associated with DNA repair. Such a modulation was concomitant with a topographical redistribution of both DNA polymerase alpha and the incorporation of BrdUrd throughout the nucleus. Taken together, these results indicate the occurrence of a dramatic response of the DNA machinery, through a possible common or at least similar behaviour when different cell lines are triggered to apoptosis. Although this possibility requires further investigation, these findings suggest an extreme attempt of the cell undergoing apoptosis to preserve its nuclear environment by switching on a repair/defence mechanism during fragmentation and chromatin margination.

Animals↗