PubMed Health⌕ Search

Biomedical subjects

G Viscomi

Publications and source records attributed to G Viscomi.

8 recordsLinked to original sources
PubMed2000

Efficient presentation of tumor idiotype to autologous T cells by CD83(+) dendritic cells derived from highly purified circulating CD14(+) monocytes in multiple myeloma patients.

To generate mature and fully functional CD83(+) dendritic cells derived from circulating CD14(+) cells highly purified from the leukapheresis products of multiple myeloma patients.CD14(+) monocytes were selected by high-gradient magnetic separation and differentiated to immature dendritic cells with granulocyte-macrophage colony-stimulating factor and interleukin-4 for 6-7 days and then induced to terminal maturation by the addition of tumor necrosis factor-alpha or stimulation with CD40 ligand. Dendritic cells were characterized by immunophenotyping, evaluation of soluble antigens uptake, cytokine secretion, capacity of stimulating allogeneic T cells, and ability of presenting nominal antigens, including tumor idiotype, to autologous T lymphocytes. Phenotypic analysis showed that 90% +/- 6% of cells recovered after granulocyte-macrophage colony-stimulating factor and interleukin-4 stimulation expressed all surface markers typical of immature dendritic cells and demonstrated a high capacity of uptaking soluble antigens as shown by the FITC-dextran assay. Subsequent exposure to maturation stimuli induced the downregulation of CD1a and upregulation of CD83, HLA-DR, costimulatory molecules and induced the secretion of large amounts of interleukin-12. Mature CD83(+) cells showed a diminished ability of antigen uptake whereas they proved to be potent stimulators of allogeneic T cells in a mixed lymphocyte reaction. Monocyte-derived dendritic cells, pulsed before the addition of maturation stimuli, were capable of presenting soluble proteins such as keyhole limpet hemocyanin and tetanus toxoid to autologous T cells for primary and secondary immune response, respectively. Conversely, pulsing of mature (CD83(+)) dendritic cells was less efficient for the induction of T-cell proliferation. More importantly, CD14(+) cells-derived dendritic cells stimulated autologous T-cell proliferation in response to a tumor antigen such as the patient-specific idiotype. Moreover, idiotype-pulsed dendritic cells induced the secretion of interleukin-2 and gamma-interferon by purified CD4(+) cells. T-cell activation was better achieved when Fab immunoglobulin fragments were used as compared with the whole protein. When dendritic cells derived from CD14(+) cells from healthy volunteers were analyzed, we did not find any difference with samples from myeloma patients as for cell yield, phenotypic profile, and functional characteristics. These studies demonstrate that mobilized purified CD14(+) cells represent the optimal source for the production of a homogeneous cell population of mature CD83(+) dendritic cells suitable for clinical trials in multiple myeloma.

Antigen Presentation↗
PubMed1999

Modifications in the metabolic pathways of benzene in streptozotocin-induced diabetic rat.

Benzene is a ubiquitous environmental pollutant primarily metabolized by a cytochrome P-450 (CYP-450) isoenzyme, CYP-450 IIE1. A consistent induction of CYP450 IIE1 has been observed in both rat and human affected by diabetes mellitus. The aim of this study was to evaluate whether streptozotocin (STZ)-induced diabetes determines modifications in the metabolic pathways of benzene in rat. Benzene (100 mg/kg per day, dissolved in corn oil) was administered i.p. once a day for 5 days. Urine samples were collected every day in STZ-treated and normoglycaemic animals, treated and untreated with benzene (n = 10). Urinary levels of trans,trans-muconic acid and of phenol, catechol and hydroquinone (free and conjugated with sulphuryl and glucuronic group) were measured by high-performance liquid chromatography (HPLC). In normoglycaemic rats during the 5 days of treatment with benzene we observed a progressive and significant decrement in the urinary excretion of phenol, phenyl sulphate and glucuronide, catechol, catechol glucuronide, hydroquinone, hydroquinone glucuronide and t,t-muconic acid (P < 0. 05). In the diabetic animals, conversely, the same metabolites showed progressively increasing urinary levels (P < 0.05). Catechol sulphate and hydroquinone sulphate levels were below the instrument's detection limit. In the comparison between diabetic and normoglycaemic benzene treated rats, the inter-group difference was significant (P < 0.05) from day 3 of treatment for t,t-muconic acid, and from day 1 for free and conjugated phenol, free and glucuronide catechol and free hydroquinone. In the normoglycaemic rat exposed to benzene the decreasing trend observed in urinary excretion of free and conjugated metabolites may be due to their capability to reduce cytochromial activity. Conversely, in the diabetic rat, urinary levels of benzene metabolites tended to increase progressively, probably due to the consistent induction of CYP-450 IIE1 observed in diabetes, which would overwhelm the inhibition of this isoenzyme caused by phenolic metabolites. Furthermore, the metabolic switch towards detoxification metabolites observed after administration of high doses of benzene is not allowed in the diabetic because of reduced glutathione-S-transferase activity. As a consequence, higher levels of hydroquinone, phenol and catechol, considered the actual metabolites responsible for benzene toxicity, will accumulate in the diabetic rat. Extrapolating these data to human, we may thus suggest that occupational exposure to benzene of a diabetic subject poses a higher risk level, as his metabolism tends to produce and accumulate higher levels of reactive benzene catabolites.

Animals↗
PubMed1995

Sendai virus and herpes virus type 1 induce apoptosis in human peripheral blood mononuclear cells.

Recent reports suggest that several viruses, besides human immunodeficiency virus, induce apoptosis in infected cells. We report here that Sendai virus or Herpes simplex virus type 1 (HSV-1), two potent inducers of interferon-alpha, caused cell death in a consistent number of human peripheral blood mononuclear cells. A careful analysis of infected cells by different techniques, such as optical and electron microscopy, DNA agarose gel electrophoresis, and cytofluorimetric analysis of DNA content, showed that cell death was of apoptotic type. Sendai virus was more apoptogenic than HSV-1, and it was further studied to understand the mechanism(s) by which it induced apoptosis. Physical (uv and heat) and chemical (beta-propiolactone) inactivation reduced or abolished the apoptogenic power of Sendai virus. The use of a novel technique, which allows the study of mitochondrial membrane potential (MMP) in intact cells by flow cytometry, showed that a decrease of MMP is concomitant with the appearance of the hypodiploid peak. These results suggest that Sendai virus and HSV-1 can be added to the list of viruses causing apoptosis, which appears to be a general mechanism occurring during viral infection.

Apoptosis↗
PubMed1988

High-performance displacement chromatography of melanotropins and their derivatives.

Mixtures containing derivatives of the biological active peptide alpha-melanocyte stimulating hormone (alpha-MSH) or beta-melanocyte stimulating hormone (beta-MSH) were purified by using reversed-phase chromatography in the displacement mode. On a 250 x 4.6 mm octadecyl silica column and with instrumentation used in analytical high-performance liquid chromatography about 30 mg of the peptide mixture were separated by using an aqueous solution of benzyldimethyldodecylamonium bromide as the displacer in a single chromatographic run. The results demonstrate the advantages of displacement over elution in preparative chromatography of peptides on the scale of tens of milligrams that is typical for physiological tissue extracts and in solid-phase peptide synthesis.

Chromatography, High Pressure Liquid↗
PubMed1981

Ultrasound examination of pubertal girls and of patients with gonadal dysgenesis.

Girls with hypogonadism caused by hypothalamic lesions or chromosomal abnormalities need accurate pelvic exams to delinate pelvic structures. This work presents an evaluation of the usefulness of ultrasound examination of the pelvis in females with aberrant sexual development. Girls with these problems often need multiple pelvic examinations to monitor their uterine response to hormone therapy. Thirty-two patients with a variety of abnormalities including Mullerian agenesis and hypothalamic hypogonadism as well as patients with abnormal karyotype commonly associated with gonadal dysgenesis and male pseudohermaphrodism were studied. Repeat ultrasound scans were performed to quantitate uterine response to therapy. Ovarian visualization was usually possible, even in prepuberal girls. Following some patients at risk for gonadal tumors may be possible using repeat ultrasound examinations. The cooperation of the patients as well as of their families was gratifying, and the girls appeared to be more relaxed during ultrasound examination than during a pelvic examination.

Adolescent↗
PubMed1981

Sonographic transducer performance cannot be evaluated with clinical images.

A wide variety of in vitro tests, some too sophisticated to perform in a clinical setting, is available to provide information on the performance of sonographic transducers. However, it is a common belief among many clinicians that clinically generated in vivo images are a necessary and sufficient test of sonographic image quality. In order to examine the sensitivity and reliability of quality judgments made from clinical images, some transducers that failed elaborate in vitro tests were used to create clinical scans. In a discrimination test between clinical images created by normal and abnormal transducers, a panel of experienced sonographers was unable to consistently identify scans made by transducers with major flaws in the beam uniformity when the defect occurred only in the near field. The study confirms that rigorous in vitro tests provide unique information on transducer performance and can reveal performance flaws that are overlooked in routine clinical images.

Humans↗