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Biomedical subjects

L Rumi

Publications and source records attributed to L Rumi.

At least 19 recordsLinked to original sources
PubMed1998

Role of arachidonic acid metabolites in the action of a beta adrenergic agonist on human monocyte phagocytosis.

The mechanisms by which beta adrenergic stimulation regulates phagocytosis of Candida albicans by human peripheral monocytes (HPM) are characterized. Isoproterenol (ISO) inhibits phagocytosis in a concentration-dependent manner. This effect was blunted by propranolol, inhibitors of phospholipase A2 (PLA2), cyclooxygenase and verapamil, pointing to a participation of arachidonic acid (AA) metabolites and calcium in the phenomenon. Prostaglandin E2 (PGE2) and dibutyryl cyclic AMP (db-cAMP) also exerted the same inhibitory effect on phagocytosis. ISO interacts with beta adrenergic receptors of HPM increasing PGE2 and cAMP. We conclude that the mechanisms by which beta adrenergic stimulation regulates phagocytosis of Candida albicans by HPM appear to be secondary to beta adrenoceptor-mediated hydrolysis of AA accompanied by an increase in PGE2 generation and cAMP production. Both PGE2 and cAMP could act as mediators of the inhibitory action of beta agonists on the HPM-phagocytosis process.

Acetophenones↗
PubMed1994

Effects of sarcoma 180 growth on interleukin-1 and circulating immune complexes.

Cultured splenic mononuclear adherent cells (SMAc) from normal BALB/c mice as well as those from mice bearing 10-day sarcoma 180 (S180), exhibited a marked increase in Escherichia coli lipopolysaccharide-stimulated interleukin-1 (IL-1) production, when compared to spontaneous values. On days 20 and 30 following S180 challenge, a decrease in this effect on IL-1 production in treated and untreated SMAc was observed. Concomitantly with the alterations in the regulation of IL-1 production during tumor growth, an increase in the levels of prostaglandin E2 and serum immune complexes could be detected. These data suggest that the immunosuppression associated with later stages of tumor development may be due to direct effects on monocytes, by means of a down-regulation of IL-1 production.

Animals↗
PubMed1976

An improved method for PHA-culturing mouse lymphocytes using Ficoll-Hypaque gradient.

A simple, reproducible method is described for in vitro culture of mouse lymphocytes purified by differential centrifugation through Ficoll-Hypaque gradient. Peripheral blood, spleen and thymus purified lymphocytes responded well to in vitro PHA stimulation as measured by blast transformation and tritiated thymidine incorporation; the lowest values were observed with thymus lymphocytes.

Animals↗
PubMed1976

Phytohemagglutinin unresponsiveness of spleen cells of mice bearing an allogeneic lymphoma.

The in vitro response of spleen cells to phytohemagglutinin (PHA) was studied in BALB mice bearing an allogeneic AKR lymphoma (progressors). A significant decrease in blast transformation and DNA synthesis was observed in these animals as compared with those rejecting the tumor (regressors) or with unchallenged controls. It is postulated that either an alteration in PHA lymphocyte receptors or the presence of enhancing serum factors may be responsible for this decrease in PHA response.

Animals↗
PubMed1976

Conditions favoring immunological enhancement of a murine allogeneic lymphoma.

An in vivo model was used which permits the growth of AKR lymphoma allografts inoculated within a glass cylinder subcutaneously implanted in BALB mice. Pretreatment of the host with acellular tumor extracts or tumor cells enclosed within a diffusion chamber significantly increased tumor incidence. On the contrary, donor spleen extracts did not alter tumor incidence while viable spleen cells within a diffusion chamber even prevented tumor development. It can be concluded that in this model a condition of maximal tumor enhancement can be attained with soluble tumor antigen but not with normal spleen extracts.

Animals↗
PubMedDate not supplied

Effect of culture supernatants from two cancer cell lines on healthy donors' monocytes.

BACKGROUND: it is well known that culture cells secrete to their medium different factors that can alter their own as well as other cells' metabolism and functions. In the present study we evaluated the effect of culture supernatants originated from two cancer cell lines, Calu-1 (lung epidermoid carcinoma) and A-427 (lung adenocarcinoma) on peripheral blood monocytes (MO) from 20 healthy donors (HD). METHODS AND RESULTS: MO were incubated with supernatants or with medium only (controls) during 2 or 18 hours. There were determined the expression of HLA-DR antigen by indirect immunofluorescence technique, the formation of reactive oxygen intermediates (NBT reduction capacity) and the phagocytic capacity (Candida albicans- anti Candida albicans system). These determinations were made also in MO from 16 patients with advanced lung cancer (LCP). Percentages of expression (media +/- SE) were: HLA-DR (+) MO: Calu-1 = 30 +/- 2; A-427 = 31 +/- 2; LCP = 52 +/- 3 (p < 0.0001 vs HD: 77 +/- 1%) NBT (+)MO: Calu-1 = 47 +/- 1; A-427 = 49 +/- 1; LCP = 56 +/- 2 (p < 0.01 vs HD: 45 +/- 2%), Phagocytic MO: Calu-1 = 38 +/- 3; A-427 = 39 +/- 2; LCP = 32 +/- 3 (p < 0.0001 vs HD: 50 +/- 1%). CONCLUSIONS: we conclude that this in vitro model reproduced characteristics found in MO from lung cancer patients, since culture supernatants induced in normal MO phenotypic and functional characteristics also found in MO from patients analyzed.

Culture Media, Conditioned↗