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Biomedical subjects

R Di Primio

Publications and source records attributed to R Di Primio.

At least 37 records · Page 2Linked to original sources
PubMed1993

Inositol lipid-mediated intranuclear signalling: a comparative analysis of in vivo labelling in interferon alpha-sensitive and -resistant Daudi lymphoma cells.

Changes in inositol lipid and diacylglycerol metabolism have been analysed in Daudi lymphoma cells treated up to 24 h with human DNA recombinant interferon alpha. Results showing a different response of nuclear phosphoinositides and diacylglycerol, compared to whole cells, suggest that the intranuclear signalling system activated by interferon in Daudi cells involves nuclear inositol lipid metabolism. A well-characterized clone of Daudi cells selected for resistance to the antiproliferative action of interferon provided controls for the specificity of results.

Adolescent↗
PubMed1993

Decrease in nuclear phospholipids associated with DNA replication.

Lipid metabolism in nuclei is very active and appears involved in the transduction of signals to the genome in response to agonists acting at the plasma membrane level. However, the precise topology of nuclear lipid metabolism and the relationship between nuclear lipids and crucial events of the cell function, such as DNA replication, have not been fully elucidated. By using a recently developed cytochemical method for detecting phospholipids inside the nucleus of intact cells at the electron microscope level, we have analyzed the changes in intranuclear phospholipids in DNA-replicating versus resting cells, which are both present in the same sample of regenerating liver after partial hepatectomy. The pattern of DNA synthesis in replicating cells has been monitored by electron microscope immunocytochemistry after bromodeoxyuridine (BrdU) labeling. The data obtained, which allow a fine localization and a quantitative analysis of both DNA synthesis and phospholipid distribution, indicate a significant reduction in the phospholipids detectable inside the nucleus in all steps of the S phase. This could depend on an increased nuclear phospholipid hydrolysis, whose products should in turn activate some of the enzymes involved in the control of DNA replication.

Animals↗
PubMed1993

Phorbol ester induces changes in the synthesis of nuclear polyphosphoinositides and expression of terminal deoxynucleotidil transferase (TdT) in nuclei of KM-3 cells.

Terminal deoxynucleotidyl Transferase (TdT) play an essential role in the immune system differentiation. KM-3 cells are lymphoblastoid cells expressing the TdT and when induced to differentiate by phorbol ester (PMA) they loose this enzyme. Therefore, because of the suggested involvement of polyphosphoinositide in controlling the nuclear events it has been analyzed the phosphorylation of nuclear polyphosphoinositides during KM-3 differentiation. When the differentiated state is reached the phosphorylation level of PIP2 increases in isolated nuclei and this is accompanied by a concomitant decrease of PIP and PA, hinting at a correlation between polyphosphoinositide metabolism and TdT expression.

Cell Differentiation↗
PubMed1992

Mouse and human hemopoietic cell lines of erythroid lineage express lamins A,B and C.

Using monoclonal antibodies, we have studied the expression of lamins A,B,C and vimentin in mouse and human erythroleukemia cells. We have found that in contrast with previous reports these cells have all three lamins. Mouse cells lack vimentin, whereas human cells express it. Lamins B and C are the most abundant lamins, whereas considerably less lamin A is detectable. Our results argue that some mouse and human hemopoietic cells can express all three lamins and that production of vimentin does not necessarily precede that of lamins A/C, as other reports have suggested in the past. The data also show that the absence of a salt resistant inner nuclear matrix is not always related with the lack of lamins A/C and vimentin, as recently proposed.

Animals↗
PubMed1992

Intracellular localization of terminal transferase during the cell cycle.

Changes in the localization of terminal transferase during the cell cycle in random cultures of human pre-T leukemia line RPMI-8402 were examined by light and electron microscopy on immunoperoxidase-stained preparations. Paraformaldehyde-fixed and saponin-permeabilized human cells were used with a monoclonal anti-human terminal deoxynucleotidyl transferase (TdT) primary reagent to demonstrate changes in enzyme distribution occurring between interphase and mitosis. Nuclear localization is found uniformly during interphase. At metaphase, however, the majority of TdT staining appears randomly distributed in the cytoplasm and traces of TdT staining remain associated with mitotic chromatin. At later phases, when the daughter cells are forming, the enzyme again appears to be restricted to the new nuclear structure.

Cell Cycle↗
PubMed1992

Ultrastructural localization of Terminal deoxynucleotidyl Transferase (TdT) in rat thymocytes.

TdT positive cells in rat thymus belong to distinct subsets as shown by light and electron microscopic immunocytochemistry. Using polyclonal antibodies to calf TdT and peroxidase labeled goat anti-rabbit IgG it has been possible to identify several subpopulations of TdT positive thymocytes. Large blasts corresponding to thymocytes at early maturational stages, are strongly positive for TdT which is diffusely distributed in both the nucleus and the cytoplasm. Smaller cells which correspond presumably to more advanced stages of maturation display nuclear TdT only, or are negative. Ultrastructural analyses of TdT indicate that the localization of the enzyme is related to the morphological features of the cells and TdT expression corresponds to maturational stages of T-cells.

Animals↗
PubMed1991

Association between nuclear matrix and terminal transferase: an electron microscope immunocytochemical analysis.

Nuclear matrix extracted from KM-3, a human pre-B leukemia cell line, appears to have a site of linkage for terminal deoxynucleotidyl transferase (TdT). The immunocytochemical analysis of the distribution of TdT using a rabbit polyclonal antibody which recognizes human terminal transferase, shows that the nuclear framework of these cells contains sites of immunoreactivity that appear uniformly distributed on the matrix fibres, while the nucleolar region is unreactive. This evidence points out the possibility that TdT could reside in the proteinaceous scaffold of the nucleus defined as nuclear matrix, thus strengthening the evidence for the metabolic and regulatory roles ascribed to this nuclear framework.

Cell Line↗
PubMed1989

[A new type of small calibre carbon fiber arterial prosthesis].

A new type of vascular prosthesis, made of pyrolytic carbon fibres, was tested on growing pigs. Fourteen grafts (4 x 33 mm) were implanted on the infrarenal aorta and removed 15 s, 60 m and 7, 15, 30, 60 and 120 days after surgery. Specimens were examined by light and scanning electron microscopy. As controls ten pigs underwent excision and re-implantation of a 30 mm segment of infrarenal aorta. Autografts were removed 7 to 120 days after surgery. All but one carbon grafts, as well as all autografts were patent at the time of removal. Basic characteristics of carbon grafts, as shown by the present study, may be summarized as follows: 1) thromboresistance of the inner surface, at the time of implantation, 2) development of a thin neo-intima, 3) rapid and complete endothelialization of the flow surface, 4) good viability of the inner layers and 5) solid anchorage to peri-graft tissues.

Animals↗
PubMed1989

[Carbon fiber composite biomaterials in the substitution of the inferior vena cava].

A new type of vascular prosthesis made of pyrolytic carbon fibres, was tested on growing pigs. Fourteen graft (8 x 30 mm) were implanted as inferior vena cava (IVC) substitutes. The blood conduits were removed 15 s, 60 min and 7, 15, 30, 60 and 120 days after implantation. Specimens were examined by light and scanning electron microscopy. Ten similar pigs underwent excision and re-implantation of 30 mm segment of IVC, and where used as controls. Carbon fibres grafts removed within 7 days after implantation were patent: at the subsequent observation times, the prosthetic segments appeared completely or partially thrombosed. Four of the 10 venous autografts failed. Shortly after implantation, a thick neointimal layer covered the inner surface of carbon grafts. This phenomenon delayed organization and neo-endothelialization of the neointima, exposing carbon segments to blood deposits.

Animals↗
PubMed1987

Immunoenzymatic method for detection of terminal deoxynucleotidyl transferase by light and electron microscopy.

Methods for using rabbit polyclonal and mouse monoclonal antibodies to detect terminal deoxynucleotidyl transferase (TdT) in human leukemia lines were developed. Use of 1% paraformaldehyde in 0.1 M Na cacodylate buffer, pH 7.6, as a fixative provides a procedure that can be used for immunofluorescence, immunoalkaline phosphatase (APAAP), or horseradish peroxidase conjugate detection procedures in these cell lines. The peroxidase procedure can also be used for electron microscopy, clearly demonstrating nuclear localization of TdT in interphase nuclei of TdT-positive cells.

Alkaline Phosphatase↗
PubMed1983

Analysis of human peripheral blood lymphocytes isolated by counterflow centrifugation-elutriation.

Human peripheral blood mononuclear cells isolated by Ficoll-Hypaque density gradient centrifugation have been fractionated by counterflow centrifugal elutriation (CCE). Six CCE fractions were obtained and subsequently analyzed as for their content of monocytes, T cells, NK cells and B cells. The various cell types were identified through the expression of specific surface membrane determinants or by cytochemical staining for alpha-naphthyl acid esterase (ANAE). Monocytes were elutriated at the highest counterflow rates whereas the majority of B cells were collected at the lowest counterflow rates. T cells as well as NK cells were mostly concentrated in the intermediate fractions. No differences in the elutriation profile of T cells with the helper-inducer or with the cytotoxic-suppressor surface phenotype were observed. However, the percentages of T cells as determined by surface marker expression decreased with increasing counterflow rates, whereas the percentage of ANAE-positive T cells increased. Yet, T cells recovered at the high counterflow rates had ANAE-reactive organelles larger than those of T cells collected at low counterflow rates. These findings suggest that T cells at different maturational stages could be separated by CCE.

B-Lymphocytes↗
PubMed1983

[Correlations between dietetic fiber and serum levels of total cholesterol and HDL-cholesterol].

We have studied 10 male subjects, in good health to look for a probable correlation between dietetic fibre and serum concentration of total cholesterol, cholesterol-HDL and triglycerides. The dosages have been made before and immediately after that the subjects had assumed, with a diet, during 13 weeks, 10 g for day of dietetic fibre. The results show a significative statistical decrease and increase. Show a significative statistical decrease (p less than 0,025) of total cholesterol and that in agreement with the literature, and an increase (p less than 0,0125) of cholesterol-HDL. Consequently it's possible to affirm that the dietetic fibre has an antiatherogenic capacity.

Adolescent↗
PubMed1982

[Study of T-lymphocyte subpopulations through monoclonal antibodies].

We studied the lymphocyte subpopulations T4+ and T8+ through monoclonal antibodies (McAb). The end of our study was focused in understanding the differences between the values mentioned by the literature and, consequently, determining our range of normality. Thus, we determined the subpopulations T4 and T8 using the antibodies OKT4 IND and OKT8 SUP, which define respectively the subpopulations T helper and T suppressor. Such determinations have been fulfilled whether on the total lymphocytes or on the lymphocytes T purified. Of course, the results obtained are different if we use the total lymphocytes or lymphocytes T purified. This confirms our suspect that the different values mentioned by the literature are determined by the two possible methods: T purified or total lymphocytes. In order to avoid interpretative mistakes, we suggest to express the values of T4+ and T8+ through the relation T4/T8; in fact, studying the single values obtained by the two different methods we proved they are different, but, at the same time, the relation T4/T8 remain unchanged in each method and is included in a "range of normality" from 1,4 to 1,7.

Antibodies, Monoclonal↗
PubMed1982

Receptors for the third complement component on a proportion of large granular lymphocytes from human peripheral blood.

Large granular lymphocytes (LGL) are nonadherent cells with cytoplasmic azurophilic granules, avid receptors for the Fc portion of IgG, and a paranuclear localization of alpha-naphthyl acid esterase or acid phosphatase. LGL constitute the bulk of TG cells (cells with receptors for sheep erythrocytes and for IgG molecules) and null cells (non-T, non-B cells). In the present study we demonstrate that 20-33% of the circulating human LGL express receptors for the third complement component (C3R). When TG cell or null cell fractions from normal individuals or non-T cells from a patient with infantile agammaglobulinaemia (which contained almost exclusively LGL) were rosetted with erythrocytes coated with antibody and complement, a variable number of C3R-bearing cells were detected. Such cells were isolated and analysed further; the great majority of them displayed the cytochemical and ultrastructural features of LGL.

Acid Phosphatase↗