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Biomedical subjects

G Cavallo

Publications and source records attributed to G Cavallo.

At least 73 records · Page 4Linked to original sources
PubMed1987

Interferon-gamma inhibits cell replication, but not pp60src activity of RSV-transformed fibroblasts.

The present study analyzes the effect of murine IFN-gamma on DNA synthesis, ornithine decarboxylase activity and phosphorylation of pp60src of Rouse sarcoma virus transformed cells. When natural or recombinant IFN-gamma was added to quiescent SR-BALB or L1210 cells, stimulated with fetal calf serum, only the highest IFN-gamma concentrations (2000 U/ml) inhibited DNA synthesis of both tumor lines. By contrast, lower IFN-concentrations (20-200 U/ml) inhibited the DNA synthesis of L1210 but not of SR-BALB tumor cells. A similar pattern of inhibition was observed when ornithine decarboxylase activity was analyzed. Finally, when the levels of phosphorylation in SR-BALB cells were analyzed after IFN-gamma treatment, no difference with untreated controls was observed, even at the highest concentrations. These results suggest that SR-BALB tumor cells are insensitive to IFN-gamma and that src oncogene activity is not affected at IFN-concentrations inhibiting cell growth.

Animals↗
PubMed1986

Supraceliac aorta-to-lower extremity arterial bypass.

From 1979 to 1986, ten patients had a revascularization procedure using the supraceliac portion of the aorta. Six patients had aortofemoral or aortoiliac bypasses and four others had additional procedures for revascularization of the lower extremities or of the visceral arteries. The latter included four renal, three superior mesenteric and three hepatic artery revascularizations. There were no postoperative deaths. One patient with chronic renal failure underwent temporary hemodialysis after the operation. The postoperative course was uneventful in the nine remaining patients. Postoperative arteriograms showed all visceral artery revascularizations to be patent. All patients were symptom-free at follow-up (mean 3.8 years, range 1 month to 7 years). One patient had a successful percutaneous balloon angioplasty for a late anastomotic stenosis in a renal artery. The operative technique is described and the specific indications for the technique are discussed in patients with renal and suprarenal aortic disease.

Adolescent↗
PubMed1986

Binding of murine 125I-labelled natural interferon-gamma to murine cell receptors.

Natural murine interferon-gamma (naMuIFN-gamma) produced by T-lymphoma cells (L12-R4) stimulated with phorbol myristic acetate was purified by use of an anti-MuIFN-gamma immunoadsorbent and was labelled with 125I to study its binding to murine cell receptors. All the cell lines examined bound naMuIFN-gamma, although the binding affinity varied considerably. By adding increasing concentrations of unlabelled naMuIFN-gamma in competition binding assays we determined dissociation constants (KD) of 8.2 X 10(-10) and 7.4 X 10(-10) M for L1210 and TS/A cells, respectively, and of 6.5 X 10(-9)M for L-929 cells. The numbers of receptors present per cell of these lines were 3000, 1000 2000 respectively. Highly purified naMuIFN-gamma as well as recombinant MuIFN-gamma competed for binding sites with 125I-labelled IFN-gamma on L1210 cells, although the latter displayed a KD greater than the former (5.8 X 10(-9) M compared to 8.2 X 10(-10) M). Moreover, protease, but not endoglycosidase, treatment of target cells prevented the subsequent binding of 125I-labelled IFN-gamma, suggesting that a protein moiety is involved in the binding of the ligand. These studies demonstrate that naMuIFN-gamma binds in a specific manner and with high affinity to murine cell receptors.

Animals↗
PubMed1985

Natural murine interferon-gamma. Evidence for post-translational proteolytic processing.

Murine interferon-gamma (MuIFN-gamma), produced by the T-cell lymphoma, L12-R4, and stimulated with phorbol myristic acetate, was purified by rat monoclonal antibodies AN-18.17.24. The purified product retained its biologic activity and consisted of two proteins (Mr = 17,500 and 16,500), as determined by sodium dodecyl sulfate-gel electrophoresis. Both species were found to be glycosylated, since their Mr values decreased to 14,500 and 13,500 when the producing cells were stimulated in the presence of tunicamycin. Analysis of intracellular and secreted forms in the presence of [35S] methionine revealed that MuIFN-gamma is synthetized as a single peptide of Mr = 17,500 and undergoes proteolytic cleavage during or after secretion. Peptide mapping by reverse phase high pressure liquid chromatography showed indeed that the peptide profile of both species is very similar, suggesting a high degree of homology in the primary structure. These results demonstrate that the molecular heterogeneity of the MuIFN-gamma is probably the outcome of proteolytic processing during or after secretion.

Animals↗
PubMed1985

Inhibition of interferon-gamma may suppress allograft reactivity by T lymphocytes in vitro and in vivo.

The addition to mixed-leukocyte reactions of monoclonal antibodies to interferon-gamma abrogated alloantigen recognition and induction of cytotoxic T lymphocytes by inducing early and highly effective suppressor T lymphocytes. This inhibitory activity was not confined to in vitro models, since daily injection of the antibodies into CBA/J mice blocked the usual rejection of allogenic tumor cells.

Animals↗
PubMed1985

Mast cell and neutrophil interactions: a role for superoxide anion and histamine.

Histamine inhibits superoxide anion (O-2) production from human neutrophils stimulated by N-formylmethionyl-leucyl-phenylalanine (FMLP). The effects of histamine are dose-dependent and competitively antagonized by cimetidine. When passively sensitized rat serosal mast cells and human neutrophils are mixed together, O-2 production from FMLP-activated granulocytes is significantly reduced, following mast cell degranulation by acetylcholine. These inhibitory effects can be counteracted by cimetidine. Exposure of non-sensitized rat mast cells to FMLP-stimulated human neutrophils causes histamine release. These results suggest bidirectional control mechanisms between mast cells and neutrophils, that further stress the role of histamine in regulating inflammatory processes.

Animals↗
PubMed1985

Morphine and methadone impact on human phagocytic physiology.

Human subjects submitted to treatment with morphine show a severe depression of phagocytosis, killing properties and superoxide production both of their polymorphonuclear leukocytes and monocytes. Polymorphonuclear leukocyte adherence, chemotaxis, random migration, myeloperoxidase content, lysozyme content and lymphocyte Rosette E formation were poorly influenced. Methadone-treated subjects show a similar effect at phagocytic level but far less evident. These results confirm those previously found in animals and reinforce the evidence of a depressive role of morphine on phagocytic physiology.

Cytotoxicity, Immunologic↗
PubMed1985

The penetration of rifampicin, pyrazinamide, and pyrazinoic acid into mouse macrophages.

The degree of penetration of rifampicin, pyrazinamide, and its metabolite pyrazinoic acid in mouse macrophages was evaluated over a period of 24 h. Cell cultures were exposed to 14C-labeled drugs at concentrations corresponding to peak, trough, and intermediate serum concentrations observed in humans after administration of therapeutic doses. The study was carried out with dead, resident, and stimulated peritoneal macrophages. The results indicated that the 3 compounds penetrate macrophages rapidly. At the lower concentrations, uptake of the 3 drugs is practically complete. With increasing concentrations, the absolute amount in the intracellular compartment increased. Comparison of the degree of penetration of the 3 drugs into dead, resident, and stimulated macrophages seems to suggest that the process of transfer through the macrophage wall is of a passive nature and not related to the metabolic state of the cells. Analysis of the binding of the 3 drugs to intracellular proteins indicated that more binding sites are probably available for rifampicin than for the other 2 drugs.

Animals↗
PubMed1985

Production of monoclonal antibodies against the carbohydrate of group A streptococci.

Mouse hybridomas were isolated by fusing P3.X63.Ag8-653 myeloma cells with spleen cells from BDF1 mice repeatedly immunized with Streptococcus pyogenes type 3 ATCC 12384. Two out of 480 growing cultures secreted antibodies against the bacterial strain used as immunogen, as evaluated by an ELISA assay. After cloning the most representative continuously growing clone, 1-181, the binding specificity of these monoclonal antibodies was determined using either Streptococci with carbohydrate of different group or different bacteria strains. Binding properties suggest that the 1.181 monoclonal antibodies specifically recognize the carbohydrate moiety of Streptococci group A.

Animals↗
PubMed1985

Susceptibility of clinical isolates of gram-positive and gram-negative organisms to cefatrizine.

The in vitro activity of cefatrizine was evaluated against 294 Gram-positive and 270 Gram-negative bacteria isolated from clinical specimens. Cefatrizine had excellent activity against Gram-positive cocci, inhibiting all except enterococci at minimal inhibitory concentrations below 1 mcg/ml. Moreover, cefatrizine was an effective antibacterial agent for most major Gram-negative species. Cefatrizine activity was tested against 34 strains of H. influenzae and 37 strains of K. pneumoniae and compared with that of other orally administered cephalosporins. Cefatrizine MIC50 values were much lower than those recorded for cephalexin and cefadroxil.

Cefatrizine↗