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Biomedical subjects

A Campa

Publications and source records attributed to A Campa.

At least 55 records · Page 3Linked to original sources
PubMed1994

Human macrophage metabolism of low density lipoprotein oxidized by stimulated neutrophils and ferritin.

The metabolism of low density lipoprotein (LDL) oxidized with phorbol myristate acetate (PMA) stimulated neutrophils plus ferritin (LDLox) by human monocyte-derived macrophage (HMDM) was studied. Binding of 125I-labeled LDLox to HMDM and further uptake and degradation were higher than for native 125I-labeled LDL. LDLox seems to be taken up by HMDM through the scavenger receptor as indicated by competition studies with unlabeled native and autoxidized LDL. An increased concentration of cellular cholesteryl esters was observed in HMDM exposed to LDLox. Oxidative modification of LDL increased its electrophoretic migration on agarose gel and also the fragmentation of apolipoprotein B. Data suggest that LDLox is incorporated by human macrophages and can potentially induce foam-cell formation.

Binding, Competitive↗
PubMed1993

Circadian variations of superoxide dismutase activity in the rat pineal gland.

The 24 h profile of the activity of the antioxidant enzyme superoxide dismutase (SOD) in the pineal gland of rats was studied. Rhythmic analysis showed a significant 24 h rhythm with an amplitude of oscillation of 25% of the 24 h mean value, that was 100.34 +/- 1.6 U SOD (nitrite). An ultradian rhythm of 9 h was also detected. The diurnal profile of superoxide dismutase activity is discussed in relation to the oxidative metabolism of the pineal gland.

Activity Cycles↗
PubMed1993

In-vitro and in-vivo studies of the decrease of amphotericin B toxicity upon association with a triglyceride-rich emulsion.

The effects of amphotericin B associated with a triglyceride-rich emulsion (AB-emulsion), shown previously to behave like lymph chylomicrons, were evaluated in vitro and in vivo. Incorporation of amphotericin B to the emulsion was monitored by UV-visible spectrophotometry. Whilst conventional amphotericin B induced a considerable K+ efflux from erythrocytes, AB-emulsion had essentially no effect. In contrast, the K+ efflux from Candida albicans was similar upon incubation either with AB-emulsion or with conventional amphotericin B. Administration to rats showed reduced mortality due to AB-emulsion compared with conventional amphotericin B. Renal toxicity was also decreased upon AB-emulsion treatment, as evaluated by serum urea and creatinine levels. These data suggest that chylomicron-like emulsions could be utilized as vehicles for amphotericin B in antifungal therapy.

Amphotericin B↗
PubMed1992

Low density lipoprotein oxidation by stimulated neutrophils and ferritin.

Low density lipoprotein (LDL) oxidation mediated by phorbol myristate acetate (PMA)- and formylmethionylleucylphenylalanine (FMLP) -stimulated human neutrophils was enhanced by 70% in the presence of ferritin. Iron released from ferritin by the superoxide anion generated in the respiratory burst of stimulated neutrophils is shown to be involved in lipoprotein oxidation. Ascorbate (100 microM), superoxide dismutase (10 micrograms/ml) and uric acid (430 microM) showed inhibitory effects of 30% [corrected], 70% and 50% on LDL oxidation, respectively. Ceruloplasmin (2.7 microM) potentiated LDL oxidation by stimulated neutrophils and ferritin, both alone and in the presence of methionine. Methionine (1 mM) and catalase (30 micrograms/ml) increased LDL oxidation by stimulated neutrophils and ferritin. These data suggest that LDL oxidation by stimulated neutrophils and ferritin may be relevant in inflammation when both neutrophils and ferritin are increased.

Apoproteins↗
PubMed1992

Superoxide dismutase and glutathione peroxidase activities in rat pineal gland.

Activities of the antioxidant enzymes superoxide dismutase (E.C.1.15.1.1) and glutathione peroxidase (E.C.1.11.1.9) were measured in the pineal gland of adult rats. For comparative purpose superoxide dismutase was also measured in the anterior hypothalamic area (suprachiasmatic region) and the liver and glutathione peroxidase in the liver. The mean activities obtained for superoxide dismutase were: pineal (103.13 +/- 4.70 N.U.), anterior hypothalamus (132.88 +/- 4.73 N.U.), liver (253.91 +/- 0.10 N.U.) and, for glutathione peroxidase were: pineal (0.027 +/- 0.005 I.U.) and liver (0.103 +/- 0.031 I.U.). It was shown for the first time that superoxide dismutase and glutathione peroxidase are present in pineal gland being part of its antioxidant defense system.

Animals↗
PubMed1989

Alpha-oxidation of alpha-hydroxyfatty acids in rat brain. Possible involvement of an alpha-peroxylactone.

Combined--but not individual--microsomal and supernatant fractions obtained from rat brains not only consume oxygen but also provoke emission from added chlorophyll. These results are consistent with literature data (Levis and Mead, J. Biol. Chem. 239, 77 [1964]) for trapping of radioactive 14CO2 following addition of alpha-hydroxy-[1-14C]stearic acid. The most plausible explanation for emission is the interaction of chlorophyll with an alpha-peroxylactone. An intermediary alpha-peroxylactone in alpha-oxidation is consistent with other available data (Salim-Hanna, Campa and Cilento, Photochem. Photobiol. 45, 849 [1987]; Campa, Salim-Hanna and Cilento, Photochem. Photobiol. 49, 349 [1989]) and, on chemical grounds, provides a feasible route to the final products.

Animals↗
PubMed1984

Low-level luminescence from microsomes exposed to enzymatic systems that generate triplet species.

Microsomes exposed to the propanal/horseradish peroxidase/O2 system develop a weak chemiluminescence. The underlying process is distinct from that occurring during lipid peroxidation because the emission intensity peaks at around 560 nm, rather than in the red, and no malonaldehyde is formed. Triplet acetaldehyde appears to be responsible for the induction of the process, which in turn leads to excitation of a component in microsomes, possibly a flavoprotein.

Aerobiosis↗
PubMedDate not supplied

Chemiluminescent determination of esterases in monocytes.

Esterase from monocytes promotes the hydrolysis of 2-methyl-1-propenylbenzoate (MPB) yielding 2-methyl-1-propenol, which is oxidized by horseradish peroxidase/H2O2 producing triplet acetone. The chemiluminescence of this reaction can be enhanced by the addition of 9,10-dibromoanthracene-2-sulphonate. The non-specific esterase present in monocytes is responsible for MPB hydrolysis, since (a) the chemiluminescence of the reaction was inhibited by fluoride, and (b) cells that do not contain a significant amount of non-specific esterases, e.g. lymphocytes and neutrophils, did not trigger light emission. The analytical application of this reaction is considered.

Benzoates↗
PubMedDate not supplied

Selective activity of butyrylcholinesterase in serum by a chemiluminescent assay.

In a previous study, we showed that purified commercial esterase activity can be detected in a chemiluminescent assay based on the hydrolysis of 2-methyl-1-propenylbenzoate (MPB) to 2-methyl-1-propenol, which is subsequently oxidized by the horseradish peroxidase (HRP)-H(2)O(2) system. The purpose of this study was to verify the applicability of this assay to human serum. The existence of an esterase activity capable of hydrolysing MPB is indicated by the fact that the MPB-serum-HRP-H(2)O(2) system consumes oxygen and emits light. Both signals were abolished by prior serum heat inactivation and were preserved when serum was stored at < or =4 degrees C. Addition of aliesterase inhibitors, such as fluoride ion and trichlorfon or the cholinesterase inhibitor eserine, totally prevents light emission. The butyrylcholinesterase-specific substrate benzoylcholine causes a delay in both O(2) uptake and light emission, while the specific acetylcholinesterase substrate, acetyl-beta-methylcholine, had practically no effect. Purified butyrylcholinesterase, but not acetylcholinesterase, triggered light emission. The finding that butyrylcholinesterase is responsible for the hydrolysis of MPB in serum should serve as the basis for the development of a specific chemiluminescent assay for this enzyme.

Animals↗