PubMed Health⌕ Search

Biomedical subjects

G Presani

Publications and source records attributed to G Presani.

At least 19 recordsLinked to original sources
PubMed1994

Simultaneous measurement by flow cytometry of phagocytosis and metabolic burst induced in phagocytic cells in whole blood by Borrelia burgdorferi.

This paper describes the interactions between a strain of Borrelia burgdorferi and phagocytic cells, measured in whole blood, by a two-color flow cytometric method, which allowed the simultaneous quantification of both the phagocytosis rate and the oxidative burst activation. The data obtained indicated that: a) phagocytosis and metabolic activation increased as a function of spirochete concentration; b) the number of ingesting cells peaked within 10 min but activation followed later, and did not involve all the phagocytosing cells; c) opsonization of borreliae with a patient's serum enhanced the two cellular activities, mostly phagocytosis. The intensity of such functions was lower than those found for Staphylococcus aureus. The flow cytometric assay of phagocytes interactions with Borrelia burgdorferi assessed in whole blood represents an experimental approach which simulates the physiological conditions in nature.

Blood↗
PubMed1994

A new flow cytometric assay for the evaluation of phagocytosis and the oxidative burst in whole blood.

Phagocytes play an important role in host defence against microorganisms and different techniques are needed to evaluate their functional activities. Here we describe a rapid, simple and reliable one step procedure to measure the phagocytosis rate and oxidative burst activation of both polymorphonuclear leukocytes (PMN) and monocytes, by means of flow cytometry using only small quantities of whole blood. The two species of bacteria employed as test microorganisms, Staphylococcus aureus and Candida albicans showed a somewhat different behaviour. We found that the present method could be used as an alternative test in the diagnosis of chronic granulomatous disease (CGD). Moreover we were able to analyse, in a one step procedure, defective phagocyte functions in a group of paediatric patients suffering from recurrent microbial infections.

Bacterial Infections↗
PubMed1993

Biological activity of a peptidoglycan extracted from Leptospira interrogans: in vitro studies.

Peptidoglycan (PG) has been isolated from some species of spirochaetes, including Leptospira interrogans. Although leptospiral PG has been chemically characterized, no study has been carried out on its potential biological activity. Since PG of Treponema and Borrelia is biologically active both in vivo and in vitro, we investigated the capacity of a leptospiral PG preparation to induce relevant biological effects. PG extracted from L. interrogans strain Teramo was mitogenic at 0.1 microgram ml-1 for human peripheral blood mononuclear cells (PBMC) since it increased the PBMC fraction positive for Ki-67, an antigen expressed by human proliferating cells; at 4 micrograms ml-1, PG was able to induce complement consumption and to stimulate leucocyte phagocytosis and the metabolic burst of resting as well as phagocytosing leucocytes. These findings indicate that Leptospira PG may play a role in modulating the immunocompetent cell functions and suggest that PG can contribute to the host response during Leptospira infection.

Cell Division↗
PubMed1992

ELISA method for quantitative measurement of IgA and IgG specific anti-gliadin antibodies.

In this study we describe the application of an enzyme-linked immunosorbent assay (ELISA) for the measurement of anti-alpha-gliadin antibodies (AGA) in absolute units (microgram protein/ml). Enriched samples of IgA and IgG AGA were obtained by means of protein A chromatography after immunoaffinity purification of pooled sera from untreated celiac patients. No cross-reactivity with other food antigens (beta-lactalbumin, soya proteins, ovalbumin) was detected. The quantitative evaluation of protein content in IgA and IgG AGA samples obtained by immunoaffinity chromatography, was performed by means of ELISA sandwich method using a reference curve obtained with pure standard human immunoglobulins. Scalar concentrations of purified IgA and IgG were then used to obtain a reference standard curve by means of an ELISA method. Such standard curve was utilized for titrating AGA in 214 sample sera. The minimal detectable concentration of IgA and IgG AGA was 0.02 micrograms/ml. The reproducibility of within- and between-assay resulted very good for IgA-AGA and acceptable for IgG-AGA. The method here described seems to be satisfactory not only for quantitative diagnostic purposes in routine screenings but also in epidemiological studies. Moreover, it can constitute a suitable way to solve practical problems of quality control of AGA ELISA assay.

Antibodies↗
PubMed1991

Simultaneous flow cytometric method to measure phagocytosis and oxidative products by neutrophils.

We developed a rapid and sensitive two-color flow cytometric method which allows the simultaneous quantification of both the phagocytosis rate and the oxidative burst activation of polymorphonuclear leukocytes (PMNLs). The oxidation of hydroethidine (HE) to ethidium bromide (EB) was performed by the oxidative neutrophil products within the cells during the respiratory burst, which was stimulated by phagocytized fluorescein-labeled Staphylococcus aureus. By means of flow cytometry we measured red EB fluorescence emission together with green fluorescence, which was emitted by the ingested fluoresceinated bacteria. The fluorescence intensity was proportional to the number of bacteria ingested. Adherent bacteria were distinguished from the ingested ones. This two-color cellular staining permits measurement of two different functions of neutrophils in one step. This method could be of interest for the determination of the interactions between neutrophils and bacteria and for the investigations on infectious diseases in chronic granulomatous disease patients.

Ethidium↗
PubMed1989

Flow cytometric detection of anti-gliadin antibodies.

A very sensitive solid-phase fluorescent immunoassay to detect anti-alpha-gliadin IgA class antibodies is described. The solid phase consisted of polystyrene carboxylated microspheres, of 5 microns diameter, coated with alpha-gliadin. Serum-specific antibodies bound to the alpha-gliadin were measured by flow cytometry using fluorescein-conjugated anti-human IgA. 41 samples were tested and the results compared with those obtained by a standard method: an enzyme-linked immunosorbent assay (ELISA). A good correlation was found between the two techniques (r = 0.96). The sera of untreated coeliac children showed significantly higher antibody values than the sera of children on a gluten-free diet or healthy control groups. The flow cytometric method was more sensitive when the Kolgomorov/Smirnov test was used to analyse the histograms. This method provides an alternative screening test for coeliac disease and may also be used to confirm borderline results obtained in the ELISA test.

Celiac Disease↗
PubMed1989

Flow cytometric analysis of DNA content in cervical lesions.

Flow cytometry is used to screen gynaecologic specimens for Cervical Intraepithelial Neoplasia (CIN) and its precancerous lesions, possibly associated with human papilloma virus (HPV), in order to investigate the role of aneuploidy as a biological marker in HPV and CIN lesions. A total of 299 cervical samples was collected by scraping and the cellular DNA content was measured using the propidium iodide staining procedure. Two groups of patients were studied; a group of 142 negative controls for cytology and groups of patients assigned to mild, moderate or severe dysplasia, carcinoma in situ diagnosed by histologic classification according to the Papanicolaou staining technique. Pathological samples showing an alteration of the DNA index or perturbation of the cellular phase S compartment ranged from 6.4% to 41.9%. Our results confirm those obtained by other authors and suggest the hypothesis that aneuploidy is present with permanence of viral DNA in early stages of carcinogenesis, which can be used as a marker in the transition from benign to malignant cells. This work is of potential interest for the possible follow-up of patients having condyloma and could aid the early diagnosis of cervical carcinoma.

Aneuploidy↗
PubMed1989

Rapid flow cytometric studies of Borrelia burgdorferi phagocytosis by human polymorphonuclear leukocytes.

The interactions between a strain of Borrelia burgdorferi and human polymorphonuclear leukocytes were studied by flow cytometry in the presence of specific or non-specific opsonizing factors. The capacity of the borrelias to stimulate leukocyte metabolism was also investigated. The results indicated that a low phagocytosis by isolated purified polymorphonuclear leukocytes did occur in the presence or absence of specific antibodies. Within whole blood the percentages of phagocytosting leukocytes increased in the presence of non-specific opsonizing factors. No stimulation of the oxidative metabolism stimulated by Borrelia was observed and PMA or zymosan stimulation of leukocytes was inhibited by the spirochaetes.

Borrelia↗
PubMed1989

Evaluation of the serum T cell population variations induced by PUVA therapy.

In the present study we evaluated the effects of UVA irradiation on the serum T cell subpopulations (CD3, CD4, CD8, CD4/CD8, NK, T lymphocytes/mm3) by means of a Fluorescence Activate Cell Sorter (F.A.C.S. 420, Becton Dikinson). Twenty-eight psoriatic patients, never previously treated with PUVA, received UVA radiations (cabin Waldman 8001 K). Blood samples were taken before therapy and after 60 J/cm2 and 120 J/cm2 irradiations. Results were compared with those of our healthy control group of volunteers. A decrease of CD4 positive cells was observed in the psoriatic group before therapy. PUVA did not induce any statistically significant modification of the populations studied, except for a progressively increasing trend of CD4 positive cells. These data seem to stress that a medium-term PUVA therapy does not significantly modify the serum level of the T cell populations.

Adult↗
PubMed1986

Functional C8 associated with human platelets.

Haemolytic assay for C8 revealed its association in functionally active form with washed human platelets. Platelet-bound C8 haemolytic activity was inhibited by F(ab')2 anti-C8 and was undetectable in the platelet suspension obtained from three C8 deficient patients. Incubation of platelets from C8 deficient individuals in normal plasma did not restore C8 haemolytic activity, indicating that platelets do not absorb C8 from plasma in vitro during platelet preparation. Thrombin, a mediator of the platelet release reaction, did not induce the release of C8 from normal platelets. Conversely, lysis of EAC1-7.9 by platelet bound C8 was not accompanied by release of beta-thromboglobulin or serotonin from the platelets. C8 was detected in a homogenate prepared from platelets as well as in the supernatant collected after high speed centrifugation of the homogenate. The association of C8 with platelets as an individual component rather than as part of the C5b-9 membrane-attack complex was supported by the following evidence: platelet bound C8 eluted from a Sephacryl S-200 column at the same volume as C8 from normal human serum; F(ab')2 anti-C8, but not F(ab')2 anti-C5, inhibited platelet C8 activity; the platelet homogenate, which lysed EAC1-7.9, had no effect on EAC43 which are susceptible to the lytic activity of the C5b-9 complex.

Blood Platelets↗
PubMed1983

An analysis of T-lymphocyte subpopulations in psoriasis using monoclonal antibodies.

We evaluated subpopulations of T-lymphocytes by using the monoclonal antibodies OKT3, OKT4 and OKT8 in two groups of psoriatic patients, with active and stable psoriasis respectively. Whereas data from the patients with stable psoriasis were similar to those obtained from the control group, the patients in an acute flare condition revealed a relative decrease in lymphocytes reactive with OKT8, and a slight increase in the proportion of lymphocytes reactive with OKT4. The results of this study are analysed.

Acute Disease↗
PubMedDate not supplied

Serum IgA and IgG antibodies to alpha-gliadin: comparison between two ELISA methods.

We have developed two ELISA methods, i.e., enzyme immunoassay (EIA) and fluorescence immunoassay (FIA), for the semiquantitative detection of specific IgA and IgG antibodies directed against alpha-gliadin. The tests differ only for the enzyme substrate and, when optimized, could be used in large routine screening of celiac disease. Several serum samples from patients with celiac disease and gastrointestinal disorders as well as from control subjects were tested. Both methods gave good correlation with clinical data, were easily performed and had some specificity features, while FIA proved to be more sensitive.

Adolescent↗
PubMedDate not supplied

[Effects of interferon on immunoglobulin production in normal subjects and in patients with selective IgA deficiency. An "in vitro" study].

The ability of Interferon (IFN) alpha, beta and gamma to induce IgA production from IgA deficient patients lymphocytes was tested "in vitro". In affected patients IgG and IgM production was similar to the normal cases but no effect on IgA production was observed. In normal cases variable concentration of alpha- beta- and gamma-IFN resulted in different immunoglobulin production. In IgA selective deficiency a low number of SmIgA bearing cells and defective transformation in IgA-plasma cells was noted as possible primary defect.

Adolescent↗
PubMedDate not supplied

Study of IL-2, IL-6, TNF alpha, IFN gamma and beta in the serum and synovial fluid of patients with juvenile chronic arthritis.

In the last few years the important role played by various cytokines in the pathogenesis of chronic inflammatory diseases has emerged. In the present study, serum and synovial fluid levels of IL-2, IL-6, TNF alpha, IFN beta and IFN gamma were evaluated in a group of 66 patients with juvenile chronic arthritis (JCA). At the same time the ESR, CRP, hemoglobin, immunoglobulins, platelet count and Ritchie index were measured. In the serum of pauciarticular patients, IL-6 and TNF alpha levels were only slightly elevated compared with controls, but there was no correlation between these cytokines and clinical and other laboratory parameters. Serum IL-2 and IFN gamma were undetectable. In contrast, in the synovial fluid IL-6 levels were very high in all of the patients examined and there was a significant correlation between synovial fluid IL-6 levels and Ritchie's articular index. TNF alpha tended to be elevated but to a lesser extent, while synovial fluid IL-2 and IFN gamma were undetectable or very low, as in the serum. In polyarticular and systemic patients, on the other hand, serum IL-6 was elevated and statistically correlated with the majority of the laboratory parameters and with the Ritchie articular index. TNF alpha levels were only slightly elevated; on the other hand, IL-2 and IFN gamma were undetectable. There was an inverse correlation between IFN beta levels and the Ritchie articular index and a significant correlation with hemoglobin levels. In conclusion, our study demonstrates that not only IL-1 (as shown in other studies), but also IL-6 and to a lesser extent TNF alpha play a central role in the pathogenesis of JCA. IFN beta on the other hand, would seem to play an anti-inflammatory role.

Adolescent↗