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Biomedical subjects

F Rossi

Publications and source records attributed to F Rossi.

At least 685 records · Page 38Linked to original sources
PubMed1983

The NADPH oxidase of guinea pig polymorphonuclear leucocytes. Properties of the deoxycholate extracted enzyme.

NADPH oxidase from stimulated guinea pig granulocytes was extracted with deoxycholate. The solubilized enzyme was stable in 20% glycerol. Solubilized enzyme was free of myeloperoxidase activity. The properties of the deoxycholate solubilized enzyme indicated that it is a high molecular weight complex with a flavoprotein, calmodulin and cytochrome b possibly forming part of the complex. Maximum activity was between pH 7.0 and 7.5. The Km value was 15.8 microM for NADPH and 434 microM for NADH indicating that NADPH is the preferential substrate.

Animals↗
PubMed1983

Studies on gliadin related peptides. I. Synthesis, purification and 1H n.m.r. characterization of the pentapeptide H-Tyr-(Gln)3-Pro-OH.

The pentapeptide H-Tyr-(Gln)3-Pro-OH has been recently postulated to be the basic repetitive unit of a sequential polypeptide contained in wheat bread alpha-gliadins, which are believed to be toxic factors in coeliac disease, gluten-dependent enteropathy. Solid-phase synthesis, purification and 1H n.m.r. characterization in water solution of this peptide are described.

Chromatography, High Pressure Liquid↗
PubMed1983

Enzymatic activation of lymphoid population following inflammatory reactions in the human appendix.

We have histochemically evaluated the LAP, AP and ANE activities of the human appendix in 100 surgical specimens. The mucosa has been particularly investigated for its different aspects during inflammatory conditions. Two main facts have been ascertained: the subepithelial location of macrophages, and the AP and ANE activities of two groups of cells in the germinal centers. Subepithelial macrophages show conspicuous AP activity that correlates with the degree of inflammatory response and of exposure to luminal antigens. In the germinal centers, AP and ANE activities disclose two further groups of positive cells, probably the same cells reacting to both technics. One group is rooted to the core of the germinal center; the other to the intermediate area between the germinal center and the follicular mantle.

Acid Phosphatase↗
PubMed1983

A contribution to the therapy of cervicocarcinoma: remarks on 40 patients presenting paraaortic metastases (1970-1979).

The Authors report survival data concerning 40 patients affected by cervicocarcinoma who, between 1970 and 1979, underwent exploratory laparotomy after pelvic radiotherapy, with detection of paraaortic lymphnode metastases. The patients subjected to laparotomy only (21 cases) have a 9-month average survival, which increases to 24 months in those with lymphadenectomy and complete pelvic surgery. While all the patients in the first group have died, in the second 3 survive at 5 years and 3 show no evidence of disease at 52,46 and 35 months from surgery. Hysterectomy with pelvic and lomboaortic lymphadenectomy, whether therapeutical or palliative, seems to be in patients with paraortic metastases provided surgery is feasable.

Adult↗
PubMed1982

[Blood sugar control in diabetics with the insulin pump. Comparison with discontinuous injections].

Eighteen insulin-dependent diabetic patients received insulin in a continuous subcutaneous infusion delivered by a portable pump. Short-term glycemic control was evaluated on the average glycemia (serum glucose was assayed seven times per 24 hours for three to five days), on the MAGE coefficient which gives an estimate of glycemic lability, and, in eight patients, on serum C-peptide concentrations. Results were compared to those recorded with two daily subcutaneous injections of a combination of regular and intermediate insulin. The average glycemia and the MAGE coefficient were 1.32 + 0.05 milligram (m + SEM) and 1 + 0.05 milligram respectively under continuous infusion, compared to 2.05 + 0.12 and 1.76 + 0.12 milligram respectively under insulin injections. Insulin requirements were significantly lower under continuous infusion (0.99 + 0.08 U/kg versus 1.35 + 0.11 U/kg). In three patients with brittle diabetes the use of the pump ensured rapid metabolic control. The advantages and drawbacks of portable insulin pumps are discussed in the light of this experience.

Adolescent↗
PubMed1982

Plasma membrane and phagosome localisation of the activated NADPH oxidase in elicited peritoneal macrophages of the guinea-pig.

The subcellular distribution of the NADPH oxidase of guinea-pig peritoneal-elicited macrophages was investigated. Post-nuclear supernatants obtained from PMA-stimulated macrophages were fractionated in discontinuous sucrose gradients. The NADPH oxidase was found to be enriched at the interface between 20 and 34 per cent sucrose. This interface was also enriched in 5'-nucleotidase, a plasma membrane marker and in glucose-6-phosphatase and NADPH-cytochrome c reductase, two endoplasmic reticulum markers. The distribution in the gradient of beta-glucuronidase, a marker of lysosomes and of succinate dehydrogenase, a marker of mitochondria was clearly different from that of NADPH oxidase and of the markers of plasma membrane and of endoplasmic reticulum. These results indicated that in stimulated-elicited macrophages the NADPH oxidase is associated with a membrane fraction. With the fractionation technique employed it was not possible to clarify whether the oxidase is located in the plasma membrane or in the endoplasmic reticulum. In order to clarify this matter the isolation of phagosomes was performed. NADPH oxidase was found to be enriched in the phagosomal fraction. Phagosomes were also found to be enriched in the plasma membrane marker 5'-nucleotidase. Glucose-6-phosphatase,, a marker of endoplasmic reticulum, and beta-glucuronidase, a marker of lysosomes were not enriched in the phagosomal fraction. The results obtained clearly suggest that the activated NADPH oxidase of peritoneal elicited macrophages of guinea pig is located in the plasma membrane.

Animals↗
PubMed1982

The respiratory burst of phagocytic cells: facts and problems.

1. The so called "soluble" oxidase(s) are not involved in the respiratory burst of guinea pig and human granulocytes and of guinea pig peritoneal resident and elicited macrophages. 2. The activation of the oxidation of NADPH by a membrane bound NAD(P)H oxidase is the main mechanism responsible for the activation of the respiration of phagocytes. 3. The oxidase is inactive in resting cells and the activated form works on the plasma membrane. 4. More than one mechanism is operative in the oxidation of NAD(P)H by cell free particles in vitro. These mechanisms vary in relation to the conditions of assay (pH and concentration of substrate). 5. Under optimal conditions in vitro the enzymatic oxidation of NADPH practically involves the univalent pathway of oxygen reduction with stoichiometry of two nanomoles of O2 formed for one nanomole of NADPH oxidized. 6. Also in intact cells all O2 is first univalently reduced to O2 and then discharged outside the cell or in the phagocytic vacuoles. 7. The main reactions involved in the O2 balance in intact cells are the univalent reduction of O2, the dismutation of O2 to H2O2 and the degradation of the peroxide through catalatic and peroxidatic mechanisms. 8. The total oxygen univalently reduced by the activated oxidase is 2-4 folds the net oxygen consumed by the cells, depending on the mechanism of H2O2 degradation. 9. All the rate of extrarespiration is accounted for by the rate of oxidation of physiological concentration of NADPH by the membrane-bound enzyme. This adequacy can be observed only under appropriate experimental conditions, because the high activity of the oxidase is not a permanent state.

Animals↗
PubMed1982

Selective enrichment of NADPH oxidase activity in phagosomes from guinea pig polymorphonuclear leukocytes.

Recent studies have demonstrated that the activated NADPH oxidase, the enzyme responsible for the stimulation of O2 consumption with O2 formation during phagocytosis, is located in the plasma membrane of leukocytes. The present work deals with whether the activation induced by phagocytosis involves the enzyme of the entire membrane or only that of the portion of the membrane that interacts with the phagocytosable particle and forms the phagosome. The results presented show that the activity of the NADPH oxidase of phagosomal membrane, isolated by centrifugation of homogenates on discontinuous sucrose gradients, is increased 12.6-fold with respect that of homogenate. In contrast, the activities of 5'-nucleotidase and of acid p-nitrophenyl phosphatase, enzyme markers of the plasma membrane not activated during phagocytosis and uniformly distributed on the entire membrane, are increased only about three-fold with respect to that of homogenate. These results indicate that during phagocytosis and activation of NADPH oxidase is a segmentary response that involves only the enzyme that forms the phagocytic vacuole. This fact is relevant for the function of toxic intermediates of oxygen reduction that are discharged in direct contact with the engulfed agent.

4-Nitrophenylphosphatase↗