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Biomedical subjects

A B Rodríguez

Publications and source records attributed to A B Rodríguez.

33 records · Page 2Linked to original sources
PubMed1997

Effect of serum from breast- or formula-fed infants on polymorphonuclear leukocyte function.

The aim of the present study was to determine the influence of serum from formula and breast-fed infants on neutrophil function (as measured by the attachment and phagocytosis of Candida albicans) as well as the chemoattractant activity of the serum. The results indicate that: (a) serum from breast-fed infants induces a greater chemoattractant activity in neutrophils than serum from 3-month-old formula-fed infants; (b) the highest values of the attachment capacity were obtained after incubation of neutrophils with serum from 1-month-old breast-fed infants; and (c) serum from breast-fed infants induces a greater phagocytic capacity against C. albicans in neutrophils than serum from formula-fed infants.

Adult↗
PubMed1997

Melatonin and the phagocytic process of heterophils from the ring dove (Streptopelia risoria).

A functional connection between the pineal gland and the immune system in mammals and birds has been established. This study investigates the effect of melatonin upon the non-specific immunity of heterophils isolated from the ring dove. The different stages of the phagocytic process: adherence to nylon fiber, spontaneous and induced mobility, ingestion of latex beads and digestion were evaluated for heterophils incubated in the presence of 5, 25, 50, 75, or 100 microM of melatonin. In addition, the chemoattractant power of the hormone for heterophils was studied. The 100 microM melatonin dose possessed a significant chemoattractant ability for heterophils whilst ingestion of latex particles was enhanced at all doses studied. The superoxide anion level, as measured by the free radicals produced during the metabolic burst, is decreased after incubation with 100 microM of melatonin.

Animals↗
PubMed1996

In vivo effect of teicoplanin and vancomycin upon haemolytic and bactericidal activity of serum against Staphylococcus aureus.

The present study was undertaken to determine whether teicoplanin and vancomycin influence the hemolytic and bactericidal activity of serum obtained from mice (Swiss, aged 15 +/- 2 weeks). Haemolytic activity was measured in CH-50 units (which represents the capacity of serum complement to lyse 50% of sheep red blood cells in the presence of specific antibody) and the bactericidal activity was estimated from the number of colony-forming units (CFU/ml) of Staphylococcus aureus that survived after 24 h of incubation in the presence of serum. The results indicate that (1) teicoplanin and vancomycin increase the haemolytic activity of serum; (2) in the serum from animals treated with both teicoplanin or vancomycin, the number of CFU/ml of Staphylococcus aureus declines; and (3) these antibiotics appear to have a similar effect upon the complement system.

Animals↗
PubMed1996

Comparative study of the effect of teicoplanin and vancomycin upon the phagocytic process of peritoneal macrophages.

The effect of Teicoplanin and Vancomycin upon the phagocytic process was compared by evaluating the different activities of the peritoneal macrophage phagocytic function from mice treated with these antibiotics. The results indicated that teicoplanin and vancomycin increased both the substrate adherence and chemotaxis of peritoneal macrophages and that neither antibiotic, at the concentrations of 10, 25, 50, 75 and 100 mg/l, had any chemoattractant capacity for peritoneal macrophages. There was an increase in the attachment of Candida albicans only in the macrophages from mice treated with vancomycin. The phagocytosis of C. albicans, Staphylococcus aureus, Escherichia coli and inert particles as well, as the nitroblue tetrazolium reduction capacity (microbicide capacity) increased in the presence of both antibiotics. The C. albicans digestion capacity increased only in the peritoneal macrophages from mice treated with teicoplanin.

Animals↗
PubMed1994

Decline in the phagocytic function of alveolar macrophages from mice exposed to cigarette smoke.

An investigation was made of the effects of a short and acute exposure to cigarette smoke on the capacity of alveolar macrophages from mice to carry out all stages of the phagocytic process. Cigarettes were commercial 80 mm filter cigarettes that contained 17 mg of tar and 1.1 mg of nicotine per cigarette. The acute exposure of each animal was with one cigarette for 15 min (until the complete consumption of the cigarette) in a box-shaped plastic chamber, 7732 cm3 vol and 450 cm2 floor surface, with a 3 cm dia airhole. Animals were sacrificed immediately after the exposure to the smoke. The results showed no differences either in the adherence or in the chemotaxis capacities between alveolar macrophages from control mice and from mice exposed to cigarette smoke. However, there was a significant decline both in attachment capacity and in ingestion capacity for Candida albicans. The reason for this was a decline in the number of macrophages with phagocytic capacity (percent of phagocytosis) and in the number of C. albicans phagocytized per cell (phagocytic efficiency). The conclusion is that a short, acute exposure to a smoke-filled atmosphere induced a decrease in the phagocytic function of alveolar macrophages.

Animals↗
PubMed1994

Effect of pinealectomy upon the nonspecific immune response of the ring-dove (Streptopelia risoria).

The different stages of the phagocytic process by granulocytes of pinealectomized or sham-pinealectomized ring doves (Streptopelia risoria) as well as hematological parameters (total white blood cells, smear, and total protein) and serum hormone levels (triiodothyronine (T3), thyroxine (T4), and corticosterone) were studied. A number of immunological parameters of the phagocytosis process, including adherence capacity, mobility rate, the phagocytosis capacity for inert particles and the digestion capacity of ingested material, were studied. Adult male ring doves were injected intravenously with either 0.1 ml of normal sheep serum (NSS) or saline (SS). Blood samples were collected before injection, and 1 hr, 3 hr, 24 hr, and 4 days afterwards. The results indicate that pinealectomy produces a significant increase in the number of total white blood cells and total protein concentration in plasma in addition to altering different stages of the phagocytic process. During the immunization study, a decrease in the percentage of leukocytes and lymphocytes and an increase in the percentage of heterophils accompanied by an increase in the concentration of serum corticosterone were observed 3 hr following treatment. For the immunological parameters, adherence capacity and latex bead ingestion were increased 3 hr after NSS injection and the NBT reduction test 3 and 24 hr after NSS treatment. In addition, the administration of NSS produced a significant increase in serum T3 and T4 concentrations 4 days following injection. These results show that pinealectomy has a marked effect on both the number and function of immune cells.

Animals↗
PubMed1994

Effect of cefepime (BMY-28142) on the hemolytic and bactericidal activity of serum in vivo and in vitro.

The present study was undertaken to determine whether cefepime (BMY-28142) could influence the hemolytic and bactericidal activity of serum both in vivo and in vitro. For the in vivo studies, mice (Swiss aged 15 +/- 2 weeks) were studied before and 1, 2, 4, 8, and 12 h after an intramuscular injection of 200 mg/kg of cefepime. Likewise, another group of mice were injected for 7 days with a daily injection of the same dose as before, and sacrificed one hour after the last injection. For the in vitro studies, samples were incubated in the presence and absence of cefepime (1/2, 1/4 and 1/8 MIC against Staphylococcus aureus) (2.5, 1.25 and 0.625 mg/l respectively). The results indicate that cefepime at sublethal concentrations increases the bactericidal activity of serum both in vivo and in vitro against S. aureus, but does not significantly modify the hemolytic activity of the complement.

Animals↗
PubMed1993

Stimulation of phagocytosis against Staphylococcus aureus by teicoplanin and vancomycin.

The constructive interference of teicoplanin with phagocytosis of Staphylococcus aureus by murine macrophages and human neutrophils, studied in vivo and in vitro respectively, was compared with that of vancomycin. Both teicoplanin and vancomycin increased the phagocytosis by macrophages. All the concentrations of teicoplanin increased the phagocytosis by neutrophils, but only the highest concentrations of vancomycin (50 mg/l and 100 mg/l) had this effect, greater values being found with teicoplanin in all cases.

Animals↗
PubMed1993

[Uptake and intraphagocytic activity of teicoplanin in human neutrophils].

The incorporation of antibiotics in phagocytes is necessary for their activity against intracellular microorganisms. The ability of Teicoplanin to enter in human polymorphonuclear leukocytes (PMNs) after infection with Candida albicans was investigated using an in vitro model previously described. Human PMNs were preincubated with Candida albicans for 30 min, after which antibiotic (100 mg/l) was added to cell suspension during 1, 5, 15, 30 and 60 min. The results were expressed as the ratio of the cellular concentration of antibiotic to the extracellular concentration (C/E). Teicoplanin bound rapidly to phagocytes (with a C/E = 2.12 after 1 min of incubation), being the cell-associated drug approximately similar during the entire incubation period. At the same time, Teicoplanin increases the percentage of mortality of Candida albicans previously ingested, which was dependent of the incubation period in its presence.

Adult↗
PubMed1992

Effect of aztreonam upon human polymorphonuclear leukocyte functions.

Aztreonam (SQ 26,776), a new synthetic monobactam with an excellent antibacterial spectrum was analyzed in vitro. In this paper, the effect of aztreonam on the phagocytic process of human neutrophils isolated from fifteen healthy volunteers was studied. Chemotaxis was not modified with aztreonam at any of the doses used (10, 20, 40, 60, 80 and 100 micrograms/ml). On the other hand, this antibiotic at 100 micrograms/ml significantly increases (P less than 0.05) Candida albicans ingestion as well as their digestion by neutrophils at 10 and 100 micrograms/ml.

Aztreonam↗
PubMed1992

Phagocytosis of latex beads by alveolar macrophages from mice exposed to cigarette smoke.

Cigarette smoking is known to alter the numerical presence and function of alveolar macrophages. It has been speculated that these cigarette-smoke-induced alterations contribute to the depressed pulmonary defence mechanism commonly demonstrated in smokers. Studies of the phagocytic and bactericidal activities of alveolar macrophages from smokers and non-smokers have yielded conflicting results. The purpose of this study was to investigate the phagocytic capacity of alveolar macrophages from mice exposed to cigarette smoke in relation to the ability to ingest inert particles (latex beads). Measurements were made before (basal values), immediately after, and 1, 12 or 24 h after exposure. Significant decreases were observed in the number of latex beads ingested by 100 macrophages (phagocytic index) and in the phagocytic efficiency for ingesting latex (mean number of latex beads ingested per activated macrophages) immediately after and 1 h after exposure, and in the number of activated macrophages (those with phagocytic activity) immediately after exposure.

Animals↗
PubMed1990

Changes in the number of leukocytes and lymphocyte subpopulations induced by exercise in sedentary young people.

The influence of physical exercise on the quantification of leukocytes and lymphocyte subpopulations has been studied. These cells were obtained from blood taken from eleven healthy young men and women who follow a sedentary life style, before and after vigorous exercise (running). The results indicate that physical activity increases the number of white blood cells and the concentrations of circulating lymphocytes. The proportion of T-lymphocytes, estimated as rosette forming cells with sheep red blood cells after cold incubation, is constant, whereas a corresponding increase in cells with receptors for C3b or Ig-Fc is also observed. The data indicate that physical activity leads to an irregular intravascular discharge in stored cells.

Adult↗
PubMedDate not supplied

Effect of prolactin, in vivo and in vitro, upon heterophil phagocytic function in the ring dove (Streptopelia risoria).

The purpose of this study was to investigate the effects of prolactin, both in vitro and in vivo, upon heterophil phagocytic activity of the ring dove, Streptopelia risoria. In vitro incubation of heterophils with either 0.1 or 100 micrograms/mL of ovine prolactin for 2 h-significantly increased both latex bead phagocytosis and Nitroblue tetrazolium (NBT) reduction, an index of phagocytic metabolic activity. Ring doves given antigen demonstrated an increase in latex bead phagocytosis and NBT reduction. The greatest increase in both of these parameters was observed in those birds which possessed elevated plasma prolactin concentrations, either through exogenous administration or naturally through being in the later stages of incubation. These results suggest that during the incubation period of the avian breeding cycle there is an increase in phagocytic activity which is a direct consequence of the elevation shown by these birds in the concentration of plasma prolactin.

Animals↗
PubMedDate not supplied

Mitogenic effect of naturally occurring elevated plasma prolactin on ring dove lymphocytes.

3H-thymidine incorporation into isolated ring dove lymphocytes in vitro was used as a measure of lymphocyte proliferation. Lymphocytes taken from doves with increased plasma concentrations of prolactin demonstrated significantly increased 3H-thymidine incorporation. In vitro incubation with mitogens significantly increased incorporation of 3H-thymidine into lymphocytes from non-breeding doves. However, similar treatment of lymphocytes taken from doves which had elevated levels of plasma prolactin failed to induce any further increase in the stimulation index. Antigen caused a significant increase in 3H-thymidine incorporation in non-breeding doves. Antigen administration also led to the production of specific antibodies. The titre of specific anti-human red blood cell (HRBC) agglutinins was greatest in those birds which also had elevated levels of plasma prolactin, reaching significance in the group of incubating doves with naturally occurring increased concentrations of plasma prolactin. The results presented here may be relevant to our understanding of the role of hormones such as prolactin on lymphocyte activation.

Analysis of Variance↗