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Biomedical subjects

M Napolitano

Publications and source records attributed to M Napolitano.

At least 73 records · Page 4Linked to original sources
PubMed1993

Immunological and clinical effects of intramuscular rIFN alpha-2a and low dose subcutaneous rIL-2 in patients with advanced malignant melanoma.

Fifteen patients with tumour recurrence following radical surgical excision of malignant melanoma were treated with a combination of interferon alpha-2a (rIFN alpha-2a) and interleukin-2 (rIL-2). Immunological monitoring (performed prior to therapy and on days 7, 21, and 28, of each course of treatment) showed significant changes of several parameters after rIFN alpha-2a and rIL-2 administration. A significant increase in cells expressing CD16 (cells bearing Fc receptor), CD25 (cells bearing IL-2 receptor), and CD56 (NK cells, activated lymphocytes), as well in levels of soluble IL-2 receptor, beta 2-microglobulin and neopterin was observed. Immunological changes were closely related to the injection of the biological agent and were more relevant during the first than the second cycle of treatment. rIFN alpha-2a and rIL-2 exerted a clear synergistic activity on the same immunological parameters. No major response was seen with the present approach: four subjects showed rapid progression of decrease during the first month of therapy, while of 11 patients who completed two courses of treatment, only five were considered in stable disease. In conclusion, our results suggest that a combination of rIFN alpha-2a and rIL-2, at dosages and schedules, used in this trial, was well-tolerated and immunologically active, but was clinically ineffective in the management of advanced melanoma.

Adult↗
PubMed1993

Uridine and stimulant-induced motor activity.

Chronic administration of uridine alters dopaminergic activity and related behavior. The present study investigated this effect using amphetamine and cocaine-induced activity and rotation in rats with unilateral dopaminergic lesions. Adult, female Sprague-Dawley rats with free access to food and water received daily intraperitoneal uridine (16 mg/kg) or an equal volume of saline. Activity was assessed for 10 min in a photocell chamber 30 min after intraperitoneal amphetamine or cocaine and 4 hr after the uridine or saline. Additional rats with unilateral dopaminergic lesions were treated comparably and assessed for stimulant-induced rotation. Uridine exerted no effect on body weight, activity, or rotation under baseline conditions. At higher doses, amphetamine and cocaine decreased activity and caused a dose-dependent increase in rotations. In the activity test, uridine-treated rats exhibited a significant increase in sensitivity to amphetamine but not to cocaine. In the rotation test, uridine-treated rats showed increased sensitivity to both stimulants. Finally, neurochemical analysis of a third set of comparably treated rats revealed that uridine blunted the amphetamine-induced increase in striatal dopamine. These observations are interpreted as indicating that chronic uridine modulates the stimulant-induced release of dopamine and, therefore, may be of therapeutic interest.

Amphetamines↗
PubMed1993

Characterization of a receptor for macrophage inflammatory protein 1 alpha and related proteins on human and murine cells.

Macrophage inflammatory protein 1 alpha (MIP-1 alpha) is a potent stem cell inhibitor and a member of a large and expanding family of related cytokines. In an effort to understand the molecular basis of the activities of MIP-1 alpha, we have sought to characterize the cellular receptors for this molecule. Our results demonstrate the presence of abundant MIP-1 alpha receptors on both human and murine cells. The receptor on K562 cells can bind a range of members of the MIP-1 alpha family and may thus be a general MIP-1 alpha family receptor. Murine FDCPmix cells also bind a range of members of this peptide family, although the receptor(s) that they express appear somewhat more selective for peptides capable of displaying stem cell inhibitory properties. The human and murine receptors do not bind members of the related interleukin 8 family of peptides and are thus distinct from the recently cloned interleukin 8 receptor. We suggest that the receptor on the murine cell is a candidate for the receptor responsible for articulating stem cell inhibitory signals following MIP-1 alpha binding.

Amino Acid Sequence↗
PubMed1992

Differences in membrane electrical properties between C3H 10T1/2 mouse embryo fibroblasts and their ionizing radiation and chemically transformed counterparts.

Membrane electrical properties of mouse embryo fibroblasts and their ionizing radiation and chemically transformed counterparts were investigated using dielectric relaxation measurements in the radio frequency range. This determination is possible because, in the radio frequency range, suspensions of cells in an electrolyte buffer show a conductivity dispersion due to interfacial polarization. An analysis of the experimental data based on a "single-shell" model showed that conductivity and permittivity of the membranes of both radiation and chemically transformed fibroblasts were lower than in normal cells. In addition, the conductivity of the cytoplasm was higher in both transformed cell types than in the normal mouse fibroblasts. We discuss the significance of these findings in view of the possible structural and functional modifications brought about by the process of neoplastic transformation.

Animals↗
PubMed1992

Inactivation of C3H 10T1/2 cells by monoenergetic high LET alpha-particles.

Inactivation of mouse C3H 10T1/2 cells in plateau-phase (7.8 x 10(4) cells/cm2) was studied by using alpha-particles from the irradiation facility installed for radiobiological experiments at the 3 MV Tandem accelerator, University of Naples. Silicon detectors and CR39 plastic track detectors were employed for dosimetric purposes. The cells were exposed to high LET monoenergetic alpha-particles (energy of 1.8 MeV at the centre of the cell nucleus, track-averaged LET of 177 keV/micron and dose-rate of 1.1 Gy/min) and low-LET 80 kVp X-rays. The X-ray survival curve showed a significant shoulder (alpha/beta = 9 Gy) while the survival curve for alpha-particles was close to exponential. The mean lethal dose of alpha-particles was 0.77 +/- 0.02 Gy and the RBE was 5.2 at 80% survival and 3.0 at 5% survival. Survival of exponentially growing cells (2 x 10(4) cells/cm2) following irradiation with the alpha-particle beam is also reported. The nuclear areas of 10T1/2 cells were measured as 299 +/- 9 micron 2 and 250 +/- 8 micron 2 for cells in log phase and plateau phase, respectively. The inactivation cross-section, obtained from the mean lethal dose, was 34 micron 2 and 37 micron 2 for cells in log phase and plateau phase, respectively. These values appear to be the maximum measured values for the inactivation cross-section of 10T1/2 cells as a function of the alpha-particle LET. This saturation cross-section is very similar to the saturation values reported in the literature for other mammalian cell lines.

Alpha Particles↗
PubMed1992

Chromosome damage induced by high-LET alpha-particles in plateau-phase C3H 10T1/2 cells.

Chromosome aberrations induced by X-rays and alpha-particles (LET = 177 keV/microns) were observed at the first mitosis in C3H 10T1/2 cells released from density-inhibited cultures. X-radiation induced more chromosome exchanges than breaks (71% vs 27% of total aberrations), while a predominance of breaks (63%) was observed after alpha-irradiation. A linear-quadratic dose-response relationship was obtained for X-rays, while that for alpha-particles was linear. The RBE values for total aberration induction (ranging from 5.1 at low doses to 4.4 at high doses) were very similar to the RBE for cell killing (from 5.2 to 4.3). The RBE for dicentric induction (approximately 2) was much lower than the RBE for the induction of both breaks (from 7 to 6) and interstitial deletions (from 9 to 7). This behaviour supports the hypothesis that chromosome deletions play a major role in the malignant transformation of 10T1/2 cells. A high correlation between cell killing and number of acentric fragments per cell was found. The number of acentrics/cell at the mean lethal dose was about 1.4. This number was reduced to 1.0 when asymmetrical interchanges, which generally result in very small deletions, were subtracted from acentrics. It could be hypothesized that very small deletions could not impair cell survival. However, an alternative hypothesis related to the aneuploid state of C3H 10T1/2 cells can be formulated. Robertsonian translocations were also observed at the first mitosis. The dose-response curve of these translocations appears to be very similar to the dose-response curve for induction of sister chromatid exchanges (observed at the second mitosis) reported by other authors studying the same cell line. This similarity could indicate a general mechanism of action of radiation on the process of recombination of genetic material.

Alpha Particles↗
PubMed1991

The gene encoding the Act-2 cytokine. Genomic structure, HTLV-I/Tax responsiveness of 5' upstream sequences, and chromosomal localization.

Act-2 is a cytokine that belongs to a superfamily of structurally related proteins. Act-2 expression is rapidly induced in T cells, B cells, and monocytes upon mitogenic stimulation. The Act-2 genomic locus is on chromosome 17q. The exons and exon/intron splice junctions have been sequenced, as have the sequences upstream of exon 1. A classical TATA box is located immediately upstream of the transcription initiation site. The upstream sequences possess promoter activity and can be functionally activated after treatment of Jurkat T cells with phythohemagglutinin plus phorbol myristrate acetate. In addition, Act-2 promoter chloramphenicol acetyltransferase constructs are expressed in human T cell lymphotropic virus type I (HTLV-I)-infected MT-2 cells and in Jurkat cells which can be induced to express the transactivator gene (tax) product of HTLV-I.

Amino Acid Sequence↗
PubMed1991

Repair of potentially lethal damage by introduction of T4 DNA ligase in eucaryotic cells.

The bacterial enzyme PvuII, which generates blunt-ended DNA double-strand breaks, and T4 DNA ligase, which seals adjacent DNA fragments in coupling to ATP cleavage, were introduced in mouse C3H10T1/2 fibroblasts using osmolytic shock of pinocytic vesicles. Cells were then assayed for their clonogenic ability. In agreement with previous studies by others, we find that the PvuII restriction endonuclease simulates ionizing radiation effects by causing a dose-dependent loss of reproductive capacity. Here we show that the concomitant treatment with DNA ligase considerably increases cell survival. Survival curves were shown to be dependent on the ligase enzyme dose and on ATP concentration in the hypertonic medium. We conclude that T4 DNA ligase is able to repair some of the potentially lethal damage produced by restriction endonucleases in eucaryotic cells.

Adenosine Triphosphate↗
PubMed1990

Identification of cell surface receptors for the Act-2 cytokine.

We have identified cell surface receptors for Act-2, a secreted protein expressed upon activation of T cells, B cells, and monocytes. Although 125I-Act-2 showed little, if any, specific binding to resting peripheral blood lymphocytes (PBL) receptors were readily detected on PHA/PMA-activated PBL and a variety of cell lines including MT-2, HL60, DMSO differentiated HL60, HeLa, and K562 cells. The equilibrium dissociation constant (Kd) is 3-12 nM for MT-2, K562, and PBL activated with PHA/PMA for 40-80 h. We have also identified a rabbit polyclonal antiserum that can block Act-2 binding to its receptors. The ability to detect specific Act-2 receptors and the development of a blocking antiserum should prove valuable in efforts to molecularly clone the Act-2 receptor and to dissect the biological actions of Act-2.

Amino Acid Sequence↗
PubMed1990

Structure, function, and regulation of the interleukin-2 receptor and identification of a novel immune activation gene.

This chapter is divided into two sections, the first dealing with a novel immune activation gene, denoted Act-2. This gene encodes a secreted protein that may represent a new cytokine. The Act-2 protein shares significant homology with proteins in two related families of small secreted proteins. Act-2 is rapidly synthesized by activated T cells, B cells and monocytes. The second section deals with interleukin-2 receptors. These receptors are now known to be comprised of three distinct classes of receptors, formed by various combinations of two IL-2 binding proteins, the alpha and beta chains. The low-affinity receptors contain alpha, but not beta chains; the intermediate-affinity receptors contain beta, but not alpha chains, and the high-affinity receptors contain both alpha and beta chains. The beta chain appears to be tyrosine phosphorylated. We discuss evidence for the existence of another protein of relative molecular mass 100,000, which appears to be a subunit of at least the high-affinity receptor.

Amino Acid Sequence↗
PubMed1989

A model for the relationship between the arterial pressure and the heart period.

This paper provides a simple model for predicting the relationship between steady-state heart rate and arterial blood pressure. Two current state-of-the-art models of the cardiovascular system as a pump operating in its circuit are reformulated and combined in order to highlight the role of the duration of the heart cycle. The proposed model establishes that the cardiac cycle lengthens linearly with the inverse of the average blood pressure. Experimental data are reported for sixteen preoperated conscious dogs resting quietly on their sides. Vagal and sympathetic blocks have been produced in four dogs in order to obtain a wide range of sympathetic and parasympathetic tones, namely, to cover the entire range of physiological values of the heart rate. For these dogs a comparison between the experimental values and the theoretical predictions shows a good agreement, the results of the linear regression model being statistically significant at the p = 0.001 level for three dogs and at the p = 0.01 level for the fourth dog.

Animals↗
PubMed1988

Urinary neopterin and immunological features in patients with Kaposi's sarcoma.

We studied neopterin excretion levels and immunological features of 20 patients affected by Kaposi's sarcoma (KS), compared to 30 normal controls. Eighteen patients had the classic form of Kaposi's sarcoma (CKS), while two patients were anti-human immunodeficiency virus (HIV) seropositive and affected by the epidemic form associated with the acquired immunodeficiency syndrome (AIDS). In CKS patients, a trend of an increase of neopterin levels with more advanced stages appeared from our data whereas a significant reduction in CD3+ and CD4+ lymphocytes subsets was observed already at early stages (P less than 0.01). CD8+ cells did not show significant variations. A significant increase in serum IgA immunoglobulins (P less than 0.05) was also observed. Comparative analysis of the two patients affected by AIDS/KS showed the profound deficit in T-cell immunity but also the prognostic value of neopterin monitoring. Furthermore these findings seem to confirm Kaposi's sarcoma as an 'opportunistic neoplasia' and indicate neopterin as a useful prognostic marker.

Aged↗
PubMed1988

Identification, cloning, and characterization of an immune activation gene.

We have identified an immune activation gene, denoted Act-2, by differential hybridization screening of an activated T-cell library. The gene is induced rapidly after T-cell activation with phytohemagglutinin, B-cell activation with Staphylococcus aureus Cowan I, and monocyte activation with lipopolysaccharide. We have isolated a cDNA containing the full-length coding region. The deduced amino acid sequence predicts an open reading frame of 92 amino acids, including a very hydrophobic N terminus, which by weight matrix score is predicted to be a signal peptide. Using a baculovirus expression system, we have shown that this gene encodes a secreted product. It is therefore possible that Act-2 represents a newly discovered cytokine.

Amino Acid Sequence↗
PubMed1988

Establishment of a new Epstein-Barr virus-immortalized cell line from chronic lymphocytic leukemia with trisomy of chromosome 12 that produces monoclonal IgM against a sheep RBC antigen.

Leukemia cells from a patient with chronic lymphocytic leukemia (CLL) were found to bind sheep RBC (SRBC) through their monoclonal surface IgM. A lymphoblastoid cell line was obtained by immortalization of leukemic cells with Epstein-Barr virus (EBV). Cultured leukemic cells were found to have a supernumerary chromosome 12, an abnormality typical of CLL of the B cell type. To our knowledge, this is the first EBV-immortalized cell line from B-CLL cells of known SRBC specificity and the third reported CLL cell line carrying trisomy of chromosome 12.

Animals↗
PubMed1987

Phenotype of chronic lymphocytic leukemia (CLL) B-cells. B-CLL cells express the Leu-8 antigen.

In the present report we studied the phenotype of peripheral blood mononuclear cells (PBMC) from 25 patients with B-cell chronic lymphocytic leukemia (CLL). Cells from all the cases expressed monoclonal surface immunoglobulins (SmIg), formed rosettes with mouse erythrocytes (MRFC) and were positive with OKB 2 and OKIa monoclonal antibodies. In addition, CCB 1 monoclonal antibody was positive in 17 out of 20, Leu-1 in 18 out of 21 and Leu-8 in 23 out of 25 cases. Double labelling experiments confirmed that the Leu-8 antigen was co-expressed on Leu-1+, CCB2+, HLA-DR+ B-CLL cells. Thus, B-CLL cells generally express the SmIg+, MRFC+, Leu-1+, OKB2+, Leu-8+ phenotype. Since it is known that normal peripheral blood B cells may be divided into two subpopulations according to Leu-8 expression, our data indicate that B-CLL cells originate from the more immature Leu-8+ B-cell subset which will respond to anti-IgM, whereas it reacts poorly to pokeweed mitogen.

Aged↗
PubMed1985

Tac-positive, HTLV-negative, T helper phenotype chronic lymphocytic leukemia cells.

In this report we describe an Italian patient with chronic T cell leukemia whose proliferating cells were mature T lymphocytes with a helper phenotype (T helper phenotype chronic lymphocytic leukemia, or Thp-CLL). Unlike other reported cases of Thp-CLL, fresh leukemic cells from this patient were positive with the anti-Tac monoclonal antibody, which recognizes the receptor for interleukin-2 (IL-2). Thus, the phenotype of these cells was similar to that expressed by Japanese patients with adult T cell leukemia (ATL) (OKT3+, OKT4+, OKT8-, Tac+). However, the Italian patient had Thp-CLL, not ATL, since his cells, unlike ATL cells, lacked human T cell leukemia virus (HTLV-I)-related DNA sequences. The Tac receptor, which appears to be modulated in vitro by the anti-Tac antibody, was biologically inactive, since the patient's cells did not respond in vitro to IL-2. In addition, they also failed to demonstrate in vitro functional activities. The clinical course was aggressive, as usual, for both Thp-CLL and ATL. Taking advantage of the description of this case, some similarities and differences between Thp-CLL and ATL are discussed, focusing on the importance of screening of HTLV-I in the differential diagnosis.

Aged↗
PubMed1985

Impairment of cellular immunity and OKT4 lymphocytes in symptom-free hemophiliacs with antibodies to human T leukemia virus III (HTLV III).

Antibodies against the human T-leukemia virus III (HTLV III) were detected by immunofluorescence in the sera of 17 out of 48 hemophiliacs (35.4%) without AIDS or ARC, frozen in 1983-84. Immunological data collected at that time were re-evaluated by separating HTLV III-positive and negative subjects. HTLV III positive patients had significantly reduced OKT4 cells (both in %: 26.1 +/- 10.9 vs 41.2 +/- 15.2; P less than 0.01; and in absolute numbers: 469 +/- 291 vs 1,038 +/- 541; P less than 0.005) and OKT3 lymphocytes (in absolute numbers: 1,234 +/- 550 vs 2,050 +/- 1,067; P less than 0.01). Subpopulations identified by other monoclonal reagents (OKT8, Leu 7, OKM1, anti-Tac) showed no significant differences between the two groups. Patients subsequently found to be seropositive had significantly more frequent anergy to skin tests to recall antigens and often an impairment of in vitro response to phytohemagglutinin A. Despite these relevant defects of some tests of cell-mediated immunity, in HTLV III-positive cases no clinical progression toward AIDS-related complex was observed in a mean period of follow-up of more than 1.5 years.

Acquired Immunodeficiency Syndrome↗