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Biomedical subjects

M L Subira

Publications and source records attributed to M L Subira.

12 recordsLinked to original sources
PubMed1994

The type of interaction with Fc gamma R in human monocytes determines the efficiency of the generation of oxidative burst.

Receptors for the Fc fragment of IgG (Fc gamma R) have a well-documented role in the generation of oxidative burst. It is tempting to speculate that the type of interaction with Fc gamma R could be a mechanism of regulation of this process. Here we report on a comparative study of the induction of oxidative burst in human monocytes activated by means of different types of interaction with Fc gamma R. We studied non-primed monocytes obtained by centrifugal elutriation from healthy donors. These cells were submitted to Fc gamma R interactions following two distinct models: one, using particulate material (IgG-SRBC leading to phagocytosis or rosetting), and another using soluble reagents followed by cross-linking of the receptors (monoclonal antibodies against Fc gamma RI and Fc gamma RII and natural ligands, namely several isotypes of murine and human IgG). Phagocytosis and oxidative burst were studied simultaneously in the monocytes, following the methodology described recently. Human non-primed monocytes were able to generate a very obvious oxidative burst response after activation of Fc gamma R by particulate material. The same response was observed when Fc gamma RII was blocked by monoclonal antibodies. Ingestion was not necessary for activation of the oxidative burst, since the model of rosetting induced a level of burst generation similar to the one obtained in the phagocytic process. Cross-linking of Fc gamma RI by soluble reagents induced production of reactive oxidative intermediates (ROI) only when the ligand-binding site of the receptor was involved. These data lead to the conclusion that Fc gamma R interaction with soluble or particulate material induces oxidative burst in non-primed human monocytes only when the binding site of natural ligands is involved. The type of interaction also determines the efficiency of the generation of ROI. This fact could represent a regulatory mechanism.

Cross-Linking Reagents↗
PubMed1993

Simultaneous evaluation of phagocytosis and Fc gamma R-mediated oxidative burst in human monocytes by a simple flow cytometry method.

In this study we describe a fast, simple, and objective flow cytometry method to quantify simultaneously phagocytosis and Fc gamma R-mediated oxidative burst in human monocytes. Peripheral blood monocytes isolated by elutriation were sequentially incubated with 2',7'-dichlorofluorescein-diacetate (DCFH-DA) and sheep erythrocytes opsonized with rabbit IgG (SRBC-IgG), and then analysed by flow cytometry. Two parameters were studied simultaneously in the same cell population: forward scatter modifications (grade of phagocytosis) and fluorescence intensity of DCFH oxidation (index of oxidative burst). We found a statistically significant correlation (r = 0.96274) between the forward scatter increase and the amount of phagocytosis as determined by light microscopy. We also found a significant correlation between the oxidative burst and phagocytosis studied both microscopically (r = 0.7714) and by flow cytometry (r = 0.78056). As the presence of DCFH did not impair monocyte phagocytosis, we conclude that this simple method could be a useful tool in functional studies of monocytes.

Animals↗
PubMed1983

[Mycosis fungoides. Clinical study and immunologic response to chemotherapy in 2 cases].

We have presented a study of two cases of Mycosis Fungoides with special emphasis on the staging of the disease as well as on the immunological findings and their modification with chemotherapy. Our objective, to relate the immunological response to clinical evolution, proposes a way of determining prognosis in the evolution of this poorly understood disease.

Adult↗
PubMed1976

[Standardization of in-vitro methods for diagnosing allergic disorders].

The various "in vitro" techniques were studied and the conclusion was reached that the hemagglutination and complement fixation tests were the most suitable for diagnosis. Sera were selected from 377 patients with very positive intracutaneous reactions to the antigens in question, the distribution being as follows: 110 sera positive to milk, 114 sera positive to eggs, 95 sera with a very marked intracutaneous reaction with gramineous pollen, and 58 with house dust. By means of the hemagglutionation technique of Boyden and the complement fixation test of Kolmer with these antigens, it was determined that the diagnostic reliability for food substances was 94,4% in the sera with positive anamnesis. For milk, there was 100% reliability in bronchial asthma and atopic dermatitis. With respect to pollen, hemagglutination gave 100% reliability in patients with positive anamnesis. The percentage with complement fixation was somewhat lower. Comparing the diagnostic reliability with hemagglutination, house dust gave an arithmetic average of 82,6% in positive anamnesis. With these antigens, hemagglutination by Boyden's technique appears the most suitable method.

Animals↗
PubMed1975

Aerosol chemotherapy in bronchopulmonary candidiasis.

One of the most frequent complications encountered in non-specific respiratory pathology of recent years is overinfection by Candida albicans. An important contributive factor is the recent massive antibiotherapy, above all with tetracyclines, favouring this overinfection. Since at present the treatment of bronchopulmonary processes is difficult owing to the lack of an effective oral or parenteral therapy, a study was carried out of 33 patients treated with nystatin and amphotericin B in aerosol form, with 3-4 sessions of treatment per day, during a minimum of 10 days. At each session either 50,000 U of nystatin or 5 mg of amphotericin B were administered. The results obtained showed that after treatment, C. albicans was no longer present in the sputum of 84% of cases treated. In view of these results it is considered that - at present - the two most suitable substances for the treatment of pulmonary candidiases are nystatin and amphotericin B in aerosol form.

Adolescent↗
PubMedDate not supplied

Humoral and cellular immunity in chronic urticaria.

In chronic recurrent urticaria of months' or years' duration, it is difficult to identify the causative factor. From an immunological point of view, various authors have attempted to demonstrate alterations in levels of immunoglobulins and complement fractions. We do not know of any previous studies of cellular immunity in this disorder. Fifty-one patients with chronic urticaria were studied, 22 females and 29 males, with ages ranging from 8 to 70 years. The patients were considered to be affected by recurrent or chronic urticaria with no clear allergic etiology. In all subjects a determination was made of serum levels of immunoglobulins G, A, M and E and of the complement fractions: C1 inhibitor, C1q, C3, C4 and C5. In addition, a study of cellular immunity was carried out on these patients. The results of tests of humoral immunity in the group of chronic urticarial patients studied showed only an increase of IgM in 41.7%. No significant changes were noted among the complement fractions. The study of cellular immunity gave normal figures for total and for B and T lymphocytes. The only finding which may be worthy of is a slight decrease in active T lymphocytes. The lymphocyte transformation test also gave a normal response to PHA and overall a normal cellular immunity was shown in these patients. At present we do not consider that the increased IgM in 40 to 45% of the cases has any pathogenic diagnostic value.

Adolescent↗