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Biomedical subjects

M R Soranzo

Publications and source records attributed to M R Soranzo.

At least 19 recordsLinked to original sources
PubMed1992

Eosinophil peroxidase deficiency: morphological and immunocytochemical studies of the eosinophil-specific granules.

Five eosinophil peroxidase (EPO)-deficient subjects were identified from 131,000 peripheral blood samples examined for routine automated analysis. The EPO-deficient eosinophils of these subjects met the main criteria established for EPO deficiency: absent or strongly decreased reaction for peroxidase, absent or strongly decreased staining with Sudan Black, and an increased ratio of the granule core volume to the total granule volume. In this report we show that this granule alteration is caused mainly by a decrease of its volume, particularly of the matrix, and that two other matrix proteins, eosinophil cationic protein and eosinophil derived neurotoxin, appear to be present in normal amounts in the EPO-deficient granules.

Adult↗
PubMed1991

Eosinophilic granuloma of the bone in Hand-Schüller-Christian disease: extensive in vivo eosinophil degranulation and subsequent binding of released eosinophil peroxidase (EPO) to other inflammatory cells.

The eosinophils from bone granuloma, bone marrow, and peripheral blood of a patient with Hand-Schüller-Christian disease (HSCD) were studied by electron microscopy and cytochemistry. Impressive eosinophil degranulation was observed. Extracellular release of eosinophil peroxidase (EPO) and EPO binding to surrounding cells were seen in the granuloma and bone marrow. Cells with peroxidase-positive plasma membrane were also observed in peripheral blood. The pattern of eosinophil degranulation showed quite different features from those described so far. In the granuloma, the process begins with intracytoplasmic release of the granule matrix content, as revealed by both extensive extragranular accumulation of EPO and progressive decrease of the matrix electron density. Core dissolution follows thereafter, leading to complete disappearance of the granules. At the end of the process, the cells show rupture of the plasma membrane and release of their content into the surrounding environment. This pattern of secretion was also observed in blood and marrow eosinophils of the patient. In view of the previously reported findings that EPO binding to inflammatory cells influences their functions, EPO release and binding to surrounding cells in HSCD may play a role in the evolution of the inflammatory lesion in the disease.

Bone Diseases↗
PubMed1989

Uptake of human eosinophil peroxidase and myeloperoxidase by cells involved in the inflammatory process.

We have recently shown that human neutrophils bind and internalize human eosinophil peroxidase (EPO) but not myeloperoxidase (MPO). In the present work, we studied the interactions of human EPO and MPO with other cells that may be involved in the inflammatory process, i.e., lymphocytes, monocytes, platelets, fibroblasts, and endothelial cells. The results indicate that EPO is bound by all the cell types considered, but is efficiently internalized only by lymphocytes, monocytes, and endothelial cells. Conversely, MPO binds appreciably only to fibroblasts and endothelial cells, although with a lower affinity than EPO, but its internalization by any of the cell types studied is hardly detectable. Furthermore, both peroxidases bind strongly to collagen fibers, whereas only EPO binds to elastin. The results suggest that EPO, owing to its high cytophilia, exerts its biological activity close to the site at which it is released from the eosinophil.

Blood Platelets↗
PubMed1986

Uptake of human eosinophil peroxidase by human neutrophils.

A cytochemical analysis was carried out for study of the interaction between human eosinophil peroxidase (EPO) and human neutrophils. To this end, neutrophils with a genetic deficiency of myeloperoxidase (MPO) were used to avoid the otherwise inevitable interference of the high endogenous MPO activity of normal neutrophils. The data show that human neutrophils incubated with EPO (1 GU/ml) rapidly bind the enzyme all over the cell surface and internalize it in small vesicles. Part of bound EPO concentrates in a limited area on the cell surface and is then internalized by means of coarse tubular channels. Fusion of the small vesicles to each other or possibly with the tubular channels gives rise ultimately to EPO-containing multivesicular bodies, which, after 30 minutes of incubation, are the only peroxidase-positive structures in the cytoplasm. Under identical experimental conditions, no binding of human MPO to the neutrophils was detected. At concentrations 10 times as high as those used for EPO, a minority of neutrophils bound MPO, but the binding pattern remained diffuse on the plasma membrane and the internalization was negligible. It seems, therefore, that the EPO trapping system of human neutrophils exhibits specificity at least among leukocyte peroxidases. Furthermore, it operates at much lower concentrations of EPO than those reported for EPO uptake by mast cells and basophils. The uptake of EPO by neutrophils may serve to sequester a potentially toxic agent, thus limiting damage to the tissue in eosinophil-rich inflammatory lesions.

Eosinophils↗
PubMed1985

Role of myeloperoxidase in respiratory burst of human polymorphonuclear leukocytes. Studies with myeloperoxidase-deficient subjects.

A comparative study of the respiratory burst [monitored as superoxide (O2-) production] of normal and myeloperoxidase (MPO) -deficient polymorphonuclear leukocytes (PMNs) was carried out on 11 MPO-deficient subjects that represent the largest sample of this kind ever studied. The rate of O2- production by isolated PMNs and whole blood from normal and MPO-deficient subjects was comparable during the initial 30-40 min of incubation with serum-treated zymosan (STZ). Afterwards, the amount of O2- produced became progressively higher in MPO-deficient cells at least until 120 min incubation with STZ. On the contrary the rate of O2- production by both cell types in response to 4-beta-phorbol-12-myristate-13-acetate (PMA) was the same. The PMNs of four MPO-deficient subjects were tested for their ingestion ability by counting the number of ingested particles on toluidine blue-stained sections of epoxy-embedded PMN suspensions. Both cell types ingested STZ particles at a comparable rate at early postphagocytic times, whereas on prolonged incubation MPO-deficient PMNs ingested more STZ particles than normal PMNs. These results suggest that the ingestion capacity of normal cells may undergo a more rapid deterioration than that of MPO-deficient cells during incubation with STZ. Evidence for a higher deterioration of normal PMNs with respect to MPO-deficient PMNs was obtained also from studies on the effect of storage on O2- generation. After standing at melting ice temperature for 3 h, normal PMNs produced less O2- than MPO-deficient PMNs in response to PMA, and the difference in O2- production by the two cell types in response to STZ was evident at earlier postphagocytic periods than with freshly isolated cells. Taken all together these results suggest that normal PMNs and MPO-deficient PMNs do not intrinsically differ in O2- generating potential and that the difference in the respiratory burst observed during phagocytosis may be accounted for by a more marked deterioration, in normal PMNs, of one or more functions related to the respiratory burst.

Humans↗
PubMed1984

A simple reliable assay for myeloperoxidase activity in mixed neutrophil-eosinophil cell suspensions: application to detection of myeloperoxidase deficiency.

Quantitation of myeloperoxidase (MPO) activity by guaiacol peroxidation (GP) assay is profoundly affected by the peroxidase present in eosinophils (EPO) that contaminate the granulocyte suspensions. Inclusion of 3-amino-1,2,4-triazole (AMT) in the GP assay permits quantitation of MPO activity in mixed neutrophil-eosinophil suspension because of the differential inhibition of EPO and MPO by AMT. Results show that: (1) the peroxidase activity of eosinophil-free granulocyte suspensions is not appreciably affected by AMT; (2) in the presence of AMT the peroxidase activities of granulocyte preparations containing different numbers of eosinophils are similar on a neutrophil basis, regardless of the number of eosinophils and correspond with the activity of eosinophil-free granulocyte suspensions; (3) AMT almost completely inhibits the activity of partially purified EPO, only slightly affecting the catalytic activity of partially purified MPO; (4) AMT completely inhibits the residual peroxidase activity of granulocyte suspensions from MPO-deficient subjects contributed by contaminating eosinophils. The GP assay in the presence of AMT was used to study the pattern of hereditary transmission of MPO deficiency. The genealogy derived on the basis of this assay was compatible with an autosomal recessive inheritance, in agreement with previously reported results, while no definite pattern of inheritance could be established by use of the GP assay without AMT. We suggest that the GP assay supplemented with AMT is the method of choice for detection of MPO deficiency, particularly partial deficiency.

Amitrole↗
PubMed1984

Congenital dyserythropoietic anaemia type II associated with a new type of G6PD deficiency (G6PD Gabrovizza).

A 6-year-old boy with chronic haemolytic anaemia was found to have glucose 6-phosphate dehydrogenase (G6PD) deficiency and the morphological, ultrastructural and serological features of congenital dyserythropoietic anaemia (CDA) type II. The patient's mother was heterozygous for G6PD deficiency. G6PD from the patient's red cells, upon partial purification and full characterization, was found to be a new variant designated G6PD Gabrovizza. We conclude that two distinct genetic abnormalities coexisted in this patient. We suggest that CDA type II may become clinically more expressed when another abnormality of the erythrocytes coexists.

Anemia, Dyserythropoietic, Congenital↗
PubMed1984

Effect of gentamicin and sisomicin on the generation of superoxide by human monocytes.

The effect of gentamicin and sisomicin on the generation of superoxide anions by human monocytes exposed to a phagocytosing stimulus, i.e. serum treated zymosan, or a soluble stimulus, i.e. 4-beta-phorbol-12-myristate-13-acetate, has been studied. Neither sisomicin nor gentamicin affected the superoxide production by stimulated monocytes. The data suggest that the reported variability in the response to aminoglycoside antibiotic therapy in certain clinical situations cannot be attributed to interference with monocyte oxidative burst.

Gentamicins↗
PubMed1983

A new method for assessment of serum-induced damage to E. coli.

A simple and rapid spectrophotometric assay for the kinetic evaluation of serum-induced damage to E. coli is described, based on changes in the optical density (OD) of a bacterial suspension. Exposure of antibody-coated E. coli to human absorbed serum results in a diphasic response, namely an increase in OD, which reaches a maximum at about 17 min and is followed by a progressive decrease in OD until a minimum value is reached after 45 min. The increase and the decrease in OD are related to bacterial death and bacterial lysis, respectively.

Blood Bactericidal Activity↗
PubMed1982

Incidence of myeloperoxidase deficiency in an area of northern Italy: histochemical, biochemical and functional studies.

Forty-five subjects with a complete deficiency of myeloperoxidase were identified in an area of the region Friuli-Venezia Giulia in north-eastern Italy using the Hemalog D system as the screening technique. Histochemical and biochemical tests performed on the leucocytes of some of these subjects confirmed the defects shown by the Hemalog D system. The defect was of genetic origin in seven subjects. The genetic origin could be suspected in another eight subjects since more than two affected members were present in a given family. Eosinophil peroxidase, which is present in MPO deficient subjects, interfered with the guaiacol assay of MPO, and in several cases masked the genetic transmission. An assay was developed using o-dianisidine as the electron donor which considerably reduced the interference by EPO. With this assay an autosomal recessive pattern of inheritance was found. The MPO deficient leucocytes had a higher respiratory burst than control cells and an impaired bactericidal activity, at early post-phagocytic periods, which became comparable to that of control cells at later stages. Particle ingestion by the MPO-deficient cells was normal.

Blood Bactericidal Activity↗
PubMed1982

New approaches to the detection of myeloperoxidase deficiency.

Family studies on myeloperoxidase (MPO) deficiency have been carried out by quantitating the peroxidase activity of granulocyte preparations with three methods, namely guaiacol peroxidation, alanine decarboxylation, and spectroscopic analysis. The guaiacol assay failed to show a definite pattern of inheritance in two families with MPO-deficient subjects. Surprisingly, the granulocytes of three histochemically MPO-negative subjects had a peroxidase activity either half or even higher than that of control subjects. The peroxidase activity of these granulocyte preparations in these three subjects showed a positive correlation to the number of eosinophils. The possibility then considered was that eosinophils may have obscured the true pattern of inheritance in this assay. Two other methods of MPO assay, which are not influenced by the presence of eosinophil peroxidase (EPO), were therefore devised. One is based on the ability of MPO, but not EPO, to catalyze decarboxylation of L-alanine in the presence of Triton X-100, and the other relies on the different spectral properties of the two peroxidases. The results obtained with these two methods (1) were strictly comparable, (2) allowed detection of both totally and partially MPO-deficient subjects, (3) differed profoundly from those obtained with the guaiacol method when eosinophil-containing granulocyte preparations were used, and (4) revealed a pattern of autosomal recessive inheritance in the two families studied. The results of the three methods were comparable when eosinophil-free granulocyte preparations were assayed. It is concluded that failure to show a pattern of inheritance in some instances of primary MPO deficiency, or deviations from the autosomal recessive mode of transmission of this defect, may be attributed to interference by EPO. It is proposed that peroxidase assay methods not subject to EPO interference, such as the two described in this article, may be used, particularly in the detection of heterozygote subjects for MPO deficiency in the presence of high eosinophil counts.

Alanine↗
PubMed1981

Evidence that eosinophils catalyze the bromide-dependent decarboxylation of amino acids.

Human eosinophils from subjects with or without myeloperoxidase (MPO) deficiency and guinea pig eosinophils are able to decarboxylate L-alanine in the presence of the cationic detergent cetyltrimethylammonium bromide (CTAB) but not in the presence of the nonionic detergent Triton X-100. Instead, both normal human neutrophils and guinea pig neutrophils decarboxylate L-alanine in the presence of either detergent. When the non-bromide-containing cationic detergent cetyltrimethylammonium hydroxide (CTAOH) is used instead of CTAB, the eosinophils from MPO-deficient subjects are unable to decarboxylate L-alanine. Decarboxylation occurs with the combination CTAOH-Br-, but not with the combinations CTAOH-I-, CTAOH-CI-, or CTAOH-F-. Bromide in the absence of CTAOH does not promote decarboxylation. Triton X-100 and deoxycholate are much less effective in promoting decarboxylation in the presence of bromide. L-Lysine and L-aspartic acid are decarboxylated to a considerably lower rate than L-alanine in the presence of CTAOH and Br-. It is concluded that the eosinophils can catalyze the bromide-dependent decarboxylation of the apolar amino acid L-alanine in the presence of a cationic detergent.

Alanine↗
PubMed1977

Biochemical studies on the leukocytes in Chediak-Higashi syndrome.

Blood leukocytes from a patient with Chediak-Higashi syndrome (CHS) were compared with normal cells for their capacity of extruding (exocytosis) the lysosomal enzyme myeloperoxidase during phagocytosis or after a treatment with the ionophore A23187 and Ca2+. A decreased rate and extent of exocytosis in phagocytizing CHS cells was observed also with the Ca2+ ionophore. This suggests that a defect in Ca2+ mobilization is not responsible for the impaired secretion of granule content. Isolated granules of CHS cells and of leukocytes were treated with the detergent Triton X-100. Since the solubilization of myeloperoxidase from the CHS granules was much lower than from the normal ones, we suggest that the former organelles have a more resistant membrane.

Calcimycin↗