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Biomedical subjects

G Monaco

Publications and source records attributed to G Monaco.

At least 55 records · Page 3Linked to original sources
PubMed1996

Movements and interactions of leukocytes in microgravity.

The mitogenic activation of human lymphocytes resuspended in vitro is dramatically reduced in microgravity. As cell-cell contacts are one of the elements essential for activation, the behaviour of human leukocytes (mainly lymphocytes and monocytes as accessory cells) in the presence of the mitogen concanavalin A was studied in the centrifuge microscope NIZEMI at 0 x g. Aggregates (formed by intercellular bindings of membrane glycoproteins via the tetravalent alpha-glucoside ligand concanavalin A) were found at 0 x g as well as at 1 x g already 12 h after the addition of the mitogen. In general, the aggregates observed at 0 x g after an incubation time of 46 and 78 h were smaller than the corresponding aggregates in the ground control. The findings are of primary importance since they confirm the indirect evidence we had from earlier Spacelab experiments and demonstrate that cell-cell contacts are occurring also in microgravity. In addition, single cells in 0 x g show a significant higher locomotion velocity than the cells at 1 x g. The fact that the locomotion capability is not decreased during the 78-h incubation with concanavalin A provides further evidence that the cells are not proceeding through the cell cycle.

Biotechnology↗
PubMed1995

p-type silicon detector for brachytherapy dosimetry.

The sensitivity of a cylindrical p-type silicon detector was studied by means of air and water measurements using different photon beams. A lead filter cap around the diode was used to minimize the dependence of the detector response as a function of the brachytherapy photon energy. The radial dose distribution of a high-activity 192Ir source in a brachytherapy phantom was measured by means of the shielded diode and the agreement of these data with theoretical evaluations confirms the method used to compensate diode response in the intermediate energy range. The diode sensitivity was constant over a wide range of dose rates of clinical interest; this allowed one to have a small detector calibrated in terms of absorbed dose in a medium. Theoretical evaluations showed that a single shielding filter around the p-type diode is sufficient to obtain accurate dosimetry for 192Ir, 137Cs, and 60Co brachytherapy sources.

Brachytherapy↗
PubMed1991

DiGeorge anomaly associated with 10p deletion.

DiGeorge anomaly (DGA) represents a heterogeneous entity, which is often sporadic, although familial cases and the association with monosomy 22q11 have been reported. Recently, a few patients with 10p deletion syndrome and immunological and other laboratory findings similar to DGA have been described. We report on an additional case of partial DGA associated with 10p deletion.

Child, Preschool↗
PubMed1990

Jejunal bacterial overgrowth and intestinal permeability in children with immunodeficiency syndromes.

Seventeen paediatric patients with immunodeficiency syndromes (10 with selective IgA deficiency, four with panhypogammaglobulinaemia, and three with selective T cell deficiency) were investigated for bacterial overgrowth of the small intestine and gut permeability to macromolecules. Five of 12 patients showed viable bacterial counts of more than 2 x 10(5)/ml in jejunal fluid. Bacterial overgrowth was also confirmed indirectly by breath hydrogen determination, which was higher than 10 ppm in four of the five patients with positive jejunal culture. Gut permeability to lactulose and L-rhamnose was abnormal in 16 of the 17 immunodeficient patients, who also had higher mean urinary excretion ratios than control subjects-mean (SD) values were 0.216 (0.160) and 0.029 (0.002), respectively. These studies indicate that bacterial overgrowth of the small intestine is a common feature in immunodeficient patients, regardless of the immunological abnormality. Moreover, these patients have an increased gut permeability to macromolecules.

Adolescent↗
PubMed1990

Penetration of cefonicid into human lung tissue and lymph nodes.

The present study was undertaken in order to investigate the penetration of cefonicid, a long-acting parenteral cephalosporin, with enhanced activity against most gram-positive and gram-negative pathogens, into human lung tissue and lymph nodes in patients undergoing open thoracotomy. Samples of lung tissue, lymph nodes and serum were obtained at various times after a single intramuscular dose of 1 g. The concentration of cefonicid was assayed by an agar diffusion method with Bacillus subtilis used as the test organism. The mean concentrations of cefonicid in serum at 2, 4, 8, 12 and 24 h after the injection were 91.5, 66.1, 35.7, 21.8 and 2.9 micrograms/ml, respectively. The mean levels of cefonicid into the hilar lymph nodes at the same times were 22.3, 18.7, 12.0, 6.9 and 1.5 micrograms/ml, respectively, while its concentrations in lung tissue were lower than those in lung lymph nodes up to the 12th hour (12.1, 14.6, 7.8, 5.4 and 1.9 micrograms/ml, respectively). Our results show that cefonicid was well distributed in interstitial fluid from which pulmonary lymph is formed and that its concentrations in lung tissue and lymph nodes were sufficient to inhibit most pathogens involved in respiratory tract infections. This finding was considered important, because it demonstrated that the high binding by plasma protein of cefonicid did not prevent it from entering lung tissue and fluids in useful quantities.

Adult↗
PubMed1989

Effect of prednisone on DR-positive T cells in children with chronic active hepatitis B.

The effect of short-term immunosuppressive treatment on the percentage of circulating DR-bearing T cells was investigated in 16 children with HBsAg-positive chronic active hepatitis. DR-positive T cells, thought to represent activated T cells, were significantly increased in all patients as compared to 10 age-matched controls [14.5 +/- 4.2% (mean +/- SD) vs. 0.4 +/- 0.1%, p less than 0.001]. Fifty-six percent of patients showed a decrease in the percentage of DR-positive T cells after 72 h of prednisone therapy. A response did not correlate with the presence of HBeAg, anti-HBeAg, or anti-delta antibodies. There was an inverse relationship (r = -0.56; p less than 0.05) between the decrease of the percent of DR-positive T cells during immunosuppression and pretreatment alanine aminotransferase levels. The persistence of high levels of circulating DR-bearing T cells during therapy may represent the immunological counterpart of more severe disease, and of nonresponsiveness to corticosteroids.

Adolescent↗
PubMed1988

[Primary intestinal lymphomas. Review of the literature apropos of a clinical case].

A rare case of primary lymphoma of the bowel in a 26 year old woman is reported and the complex problems of diagnosis and treatment are examined. The importance of establishing the primary or secondary nature of this tumour of the small bowel is emphasised. This is because primary intestinal tumours require the most radical treatment possible even in advanced stages of the disease in order to avoid complications and to identify the areas involved in the proliferative process. Finally the importance of continuing surgery with drug and radiation treatment in order to improve prognosis is emphasised.

Adult↗
PubMed1987

Action of anticytoskeletal compounds on in vitro cytopathic effect, phagocytosis, and adhesiveness of Trichomonas vaginalis.

The cytopathic effects of Trichomonas vaginalis treated with inhibitory concentrations of anticytoskeletal compounds (mebendazole, griseofulvin, colchicine, taxol, and cytochalasin B) were studied in mouse CLID fibroblast cultures. The evaluation, at different times, of cell numbers and morphological alterations showed that cytopathic effect was considerably reduced when protozoa were pretreated with mebendazole and griseofulvin, whereas colchicine, taxol, and cytochalasin B had less effect. Furthermore, treatment with mebendazole, griseofulvin, and colchicine decreased adhesiveness of the protozoan, whereas treatment with cytochalasin B and colchicine completely inhibited its phagocytic activity. From these results it may be concluded that alterations induced in the trichomonal cytoskeleton may affect its adhesiveness and its in vitro cytopathic effect, but there is no direct correlation between protozoan phagocytosis and its in vitro pathogenic effect.

Alkaloids↗
PubMed1986

Inhibition of Trichomonas vaginalis replication by the microtubule stabilizer taxol.

Taxol, a plant alkaloid stabilizer of microtubules, inhibits in vitro the replication of the human pathogenic flagellate Trichomonas vaginalis in a dose-dependent fashion. Micromolar concentrations of the drug induce massive assembly of microtubules, resistant to antimicrotubule agents, and block the mitosis of the protozoa at an early stage preceding the formation of the spindle fibers and the depolymerization of the axostylar microtubules. Some hypotheses involving the inactivation of the microtubule-organizing centers and the stabilization of axostylar microtubules are formulated to explain the mechanism of action of taxol.

Alkaloids↗
PubMed1986

Evaluation of Pseudomonas aeruginosa influence on the cytoskeleton of Hep-2 cells.

The cell cytoskeleton (microtubules, microfilaments and intermediate filaments) plays an important role in many cell functions, such as maintenance of cell locomotion, movement and compartimentalization of intracellular organelles and cell-to-cell interaction. Therefore, cytoskeleton alterations may result in sever impairment of cell functions. The aim of this paper was to study the in vitro effects of Pseudomonas aeruginosa on the cytoskeleton of cultivated Hep-2 cells. Cytoskeleton modifications were evidenced by immunofluorescence using monoclonal and polyclonal antibodies against tubulin and vimentin, and rhodamine conjugated phalloidin, that specifically binds to actin microfilaments. We report here that P. aeruginosa has a strong cytopathic effect on monolayers within a few hours of contact with the cells, and influences the organization of microfilaments, but has no discernable effect on microtubules or intermediate filaments.

Actin Cytoskeleton↗
PubMed1985

Impaired suppressor activity in children affected by coeliac disease.

Immunoregulatory cells were enumerated in 19 coeliac disease children on a gluten free diet by means of monoclonal antibodies that define total T lymphocytes (T3), helper/inducer T cells (T4), suppressor/cytotoxic T cells (T8) and monocytes (M1), as well as by means of surface receptors for Fc fragments of IgM and IgG (T mu and T gamma, respectively). In addition, suppressor cell function was assessed in 17 coeliac disease patients by examining the ability of concanavalin-A (Con-A)-activated suppressor cells to inhibit autologous cell response to mitogenic stimulus as compared with age-matched controls. No statistically significant differences were found in the percentages of subsets defined by monoclonal antibodies between coeliac disease patients and age-matched controls, whereas coeliac disease patients had a significant decrease of the subpopulation bearing membrane receptor for Fc fragment of IgG. Mean value was 8.5% in coeliac patients versus 13.4% in age-matched controls. In the functional assay, mononuclear cells from 10 out of 17 coeliac disease patients either totally or partially failed to suppress responder cells after Con-A-activation. This defect is not related to HLA-DR status, because no difference was found between patients-HLA-matched and unmatched normal individuals. In this assay, mononuclear cells of three coeliac disease patients with low suppressor activity were able to inhibit responder cells to the same extent as controls, when indomethacin was used to block prostaglandin production in the induction phase of Con-A-activated suppressor cells. Our results suggest that an abnormality in immunoregulation may play a role in the pathogenesis of coeliac disease.

Adult↗