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Biomedical subjects

C Ordóñez

Publications and source records attributed to C Ordóñez.

At least 19 recordsLinked to original sources
PubMed2003

Cytotoxic effects of two antimolting insecticides in mammalian CHO-K1 cells.

Cytotoxicity of two insect growth regulators, diflubenzuron, a benzoylphenylurea derivative that inhibits the synthesis of new chitin in target organisms, and pyriproxyfen, an insect juvenile hormone analogue, were tested on CHO-K1 cultures, using the neutral red incorporation assay. Both compounds displayed cytotoxic effects that rise with time exposure. The presence of either fetal calf serum or bovine serum albumin diminished significantly the cytotoxicity of both compounds, thus pointing to a strong protein binding. In addition, extensive metabolization with rat liver submitochondrial fraction gave rise to metabolites less toxic than the parent compounds, implying the relative safety of both diflubenzuron and pyriproxyfen in mammals.

Animals↗
PubMed2002

Alterations of the glutathione-redox balance induced by metals in CHO-K1 cells.

The effects of cadmium (Cd(2+)), mercury (Hg(2+)), lead (Pb(2+)), copper (Cu(2+)) and nickel (Ni(2+)) on the glutathione (GSH)-redox cycle were assessed in CHO-K1 by the neutral red uptake inhibition (NR) assay (NR(6.25), NR(12.5) and NR(25)). Mercury proved to be the most and lead the least toxic of the metals tested. The effects on GSH content and intracellular specific activities of enzymes involved in the GSH-redox balance were measured after a 24-h exposure. Total GSH content increased significantly in cultures exposed to the lowest metal concentration assayed (NR(6.25)), but fell to below control values when exposed to concentrations equivalent to NR(25). Oxidised glutathione content dropped significantly at NR(6.25), while somewhat higher values were obtained for cultures exposed to higher doses. Glutathione peroxidase (Gpx) activities were 1.2-, 1.5-, 1.6-, 2.0- and 2.5-fold higher than untreated controls for cadmium, copper, mercury, nickel and lead, respectively, at concentrations equivalent to NR(6.25). Gpx activity declined at metal concentrations equivalent to NR(12.5) and NR(25). Glutathione reductase activity remained almost unchanged except at low doses of mercury, nickel and lead. Glutathione-S-transferase activity decreased at rising metal concentrations. The results suggest that a homeostatic defence mechanism was activated when cells were exposed to doses equivalent to NR(6.25) while the ability of the cells to respond weakened as the dose increased. A close relationship was also observed between metal cytotoxicity, total GSH content and the dissociation energy of the sulphur-metal bonds. These facts confirm the involvement of antioxidant defence mechanisms in the toxic action of these ions.

Animals↗
PubMed2002

Changes in glutathione-redox balance induced by hexachlorocyclohexane and lindane in CHO-K1 cells.

1. The basal cytotoxic effect of the organochlorine pesticides hexachlorocyclohexane and lindane on CHO-K1 cultures was assessed at fractions of their lethal doses as determined by the neutral red incorporation (NRI) assay (NRI(6.25), NRI(12.5) and NRI(25)). The sulphur-redox cycle enzymes glutathione peroxidase, glutathione reductase and glutathione S-transferase, and total and oxidized glutathione were evaluated at several points during the standard growth curve of the cultures. 2. After incubation with each compound for 24 h, both glutathione peroxidase and reductase showed a substantial increase at the lowest exposure doses (NRI(6.25))--more significantly for lindane than for 1,2,3,4,5,6-hexachlorocyclohexane (HCH)--and dropped at higher doses of both compounds. The reduced and oxidized glutathione content was greatly diminished at the lower exposures, whereas the total glutathione content was higher at NRI(12.5) values. 3. Changes in cell membrane integrity were assessed for a wide range of pesticide concentrations with the lactate dehydrogenase release assay and lipid peroxidation. Membrane leakage and peroxide production were significantly enhanced at concentrations of HCH 50 microg ml(-1), although this effect was not significant at lindane concentrations < 200 microg ml(-1). 4. Lipid peroxidation increased with exposure to HCH at concentrations as low as NRI(6.25), whereas in the case of lindane, this increase was only significant at doses of NRI(25) and above.

Animals↗
PubMed2001

Analysis of pyridoquinoline derivatives by liquid chromatography/atmospheric pressure chemical ionization mass spectrometry.

A method using liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (LC/APCI-MS) has been developed for the characterization and determination of pyridoquinoline derivatives 4,6-bis(dimethylaminoethylamino)-2,8,10-trimethylpyrido[3,2-g]quinoline, 4,6-bis(dimethylaminoethoxy)-2,8,10-trimethylpyrido[3,2-g]quinoline and 4,6-bis[(dimethylaminoethyl)thio]-2,8,10-trimethylpyrido[3,2-g] quinoline, all with potential antitumor properties. LC separation was performed on a conventional C18 column using a binary mobile phase composed of acetonitrile and 50 mM aqueous ammonium formate at pH 3. The APCI mass spectra obtained showed that proton addition giving [M + H]+ was the common mode of ionization to the amino- and thiopyridoquinolines, whereas the alkoxypyridoquinoline was identified by the main formation of the [M - (C2H3)N(CH3)2 + H]+, followed by the [M + H]+ ion. The LC separation conditions and MS detection parameters were optimized for the determination. The analytical method was also applied to the determination of these pyridoquinoline derivatives in fetal calf serum using liquid-liquid extraction with dichloromethane. Acceptable recovery values were obtained, ranging between 45 and 98%.

Acetonitriles↗
PubMed2001

Obtaining a protein concentrate from integral defatted sunflower flour.

Proteins which are found in integral defatted sunflower flour (27% of protein in dry weight) allow us to produce a protein concentrate by means of extraction of proteins with a basic pH solution, followed by their precipitation with an acid pH solution. Once the suitable conditions for pH and temperature were fixed in order to carry out these processes, a solid proteic concentrate (71% of protein in dry weight) was obtained which was rich in glutamic and aspartic acids, with a liquid supernatant very rich in phosphorus and potassium, which might be used as an agricultural fertilizer.

Amino Acids↗
PubMed2001

Cyclodiene organochlorine insecticide-induced alterations in the sulfur-redox cycle in CHO-K1 cells.

The effect of the cyclodiene organochlorine pesticides aldrin, dieldrin and endosulfan was assessed on CHO-K1 cultures at fractions of their lethal doses, determined by the neutral red (NRI) incorporation assay (NRI6.25, NRI12.5 and NRI25). Glutathione peroxidase, reductase and S-transferase, and total and oxidised glutathione were evaluated along the standard growth curve of the cultures. After a 24-h incubation with each insecticide, glutathione peroxidase incurred a large increase, while glutathione reductase and S-transferase activities were slightly higher than untreated controls. Unlike oxidised glutathione, the content of total glutathione declined significantly after exposure to cyclodiene insecticides. Changes in cell membrane integrity were assessed by the lactate dehydrogenase (LDH) release assay and lipid peroxidation for a wide range of pesticide concentrations. Membrane leakage and peroxide production were significantly enhanced at concentrations of aldrin and as low as 12.5 microg/ml, whereas dieldrin and endosulfan increased membrane fragility at much higher concentrations.

Aldrin↗
PubMed2000

Muscle and serum changes with salbutamol administration in aerobically exercised rats.

Treatment of experimental animals subjected to 90 days physical training programme plus repeated doses of salbutamol, a beta-adrenergic agonist, administered under two different regimes: therapeutic (16 microg/kg body weight, twice a day) and doping (3 mg/kg body weight, twice a day), caused a marked increase in size of skeletal (soleus, gastrocnemius and plantaris) leg muscles. Adrenergic involvement of salbutamol-linked hypertrophy was demonstrated by co-administration of the non-specific beta-adrenergic antagonist D,L-propranolol (10 mg/kg body weight twice a day). The salbutamol-induced muscle hypertrophy was associated with an early increase in creatine phosphokinase (CK) and its myocardial isozyme (CKmb), without significant changes in lactate dehydrogenase (LDH), alanine aminotransferase (AAT) and aspartate aminotransferase (DAT). The induction of muscle-injury biomarkers was completely abolished by co-administration of propranolol, thus suggesting the adrenergic involvement of these alterations.

Adrenergic beta-Agonists↗
PubMed2000

Alterations on polyamine content and glutathione metabolism induced by different concentrations of paraquat in CHO-K1 cells.

The effect of herbicide paraquat has been assessed on CHO-K1 cultures at different concentrations. Glutathione peroxidase, reductase and S-transferase, as well as total and oxidized glutathione, were evaluated along the standard growth curve of the cultures. Paraquat was then administered during mid-log phase at concentrations that produced a calculated lethality of 6.25%, 12.5% and 25%, using the lysosomal dye assay, neutral red. After 24hr of incubation with paraquat, glutathione peroxidase suffered a large dose-response increase, unlike glutathione reductase and S-transferase, the activities of which were lower than untreated controls. The profile of total glutathione content was similar to that found for glutathione peroxidase, increasing with the administered doses of the herbicide. Polyamine content has been also studied at the same concentrations of paraquat, showing that intracellular spermidine and spermine pools were negatively affected with paraquat in a dose-response manner, unlike putrescine, which maintained elevated pools at the three concentrations assayed.

Animals↗
PubMed1999

S-adenosylmethionine synthesis in Leishmania infantum promastigotes.

Methionine adenosyltransferase (MAT), S -adenosylmethionine (AdoMet), and S -adenosylhomocysteine (AdoHcy), have been analysed at different time-points during the growth curve of Leishmania infantum. MAT activity and AdoMet content peaked in the lag and early log phases, whereas higher levels of AdoHcy were found in stationary phase cells. MAT activity of cell extracts displayed hyperbolic kinetics for both its substrates, l -methionine and ATP, with km values of 35 microm and 5 m m, respectively. MAT has an absolute requirement for divalent cations, and is dependent on sulfydryl protective agents. Unlike other sources, L. infantum MAT activity seems to be transcriptionally regulated, with an accumulation of MAT-mRNA during rapid growth periods of promastigotes.

Adenosylmethionine Decarboxylase↗
PubMed1999

Early alterations of polyamine metabolism induced after acute administration of clenbuterol in mouse heart.

An acute treatment of mice with clenbuterol, a beta-adrenergic agonist, produced a marked increase of polyamines levels in heart, particularly during the early phase of administration of the drug. A single dose of 1.5 mg/kg caused as much as a 10 fold induction in activity of ornithine decarboxylase (ODC) and 3 to 4 fold increase in levels of putrescine, spermidine and spermine in mouse heart. Maximum changes were observed 3 to 4 hours post-administration of clenbuterol. This treatment did not produce any change in S-adenosylmethionine decarboxylase activity. The induction of cardiac ODC by clenbuterol was also dose dependent with a peak at about 5 micromol/kg. Co-administration of difluoromethylornithine, an irreversible inhibitor of ODC, or propranolol, a nonspecific beta-antagonist, with clenbuterol completely prevented the induction of ODC activity as well as the increase in polyamine levels in heart. However, pretreatment with alprenolol or metoprolol, the specific beta1 and beta2-antagonists, respectively, produced only partial prevention. The cardiac ODC from controls as well as clenbuterol treated mice exhibited similar affinity (Km) for its substrate, ornithine, while maximum enzyme activity (Vmax) was about 14 fold higher in clenbuterol treated mouse heart than in the control. Clenbuterol produced no change in the level of specific ODC mRNA or the protein, but the enzyme from the drug-treated mouse heart was considerably more stable than the control. Pretreatment of mice with either cycloheximide or actinomycin D followed by administration of clenbuterol could not prevent the induction in ODC activity suggesting that de novo biosynthesis of the enzyme protein or ODC mRNA was not responsible for induction of ODC activity. Post-translational changes in ODC may be responsible for an early increase of ODC activity due to clenbuterol treatment.

Adenosylmethionine Decarboxylase↗
PubMed1998

Polyamine-mediated heart hypertrophy induced by clenbuterol in the mouse.

The use of beta-agonists as growth-promoting agents in cattle could lead to toxic side-effects in man. One such effect is the accumulation of polyamines which seem to be implicated in muscle and heart hypertrophy. We have studied the induction of cardiac hypertrophy after treatment with clenbuterol and the role of polyamines in this effect. Treatment of mice with repeated doses of clenbuterol, a specific beta-adrenergic agonist, resulted in a marked increase in heart muscle weight whereas total body weight did not change significantly. Clenbuterol-linked cardiac hypertrophy could be prevented by co-administration of either the non-specific beta-adrenergic antagonist, propranolol, or the irreversible inhibitor of ornithine decarboxylase, alpha-difluoromethylornithine. The clenbuterol-induced cardiac hypertrophy was associated with a corresponding increase in the level of the polyamines putrescine, spermidine and spermine. These observations are indicative of the role of polyamines in cardiac hypertrophy induced by clenbuterol.

Adrenergic beta-Agonists↗
PubMed1998

Plasma and muscle polyamine levels in aerobically exercised rats treated with salbutamol.

The induction of hypertrophy of cardiac and skeletal muscles has been studied after treatment with two different salbutamol dosages, therapeutic and doping. Treatment of rats subjected to a physical training schedule with repeated doses (16 microg kg(-1) per day or 3 mg kg(-1) per day) of salbutamol, a specific beta-adrenergic agonist, induced a marked increase in both skeletal and heart-muscle weight, whereas total body weight did not change significantly. Adrenergic involvement of salbutamol-linked muscle hypertrophy was demonstrated by co-administration of the non-specific beta-adrenergic antagonist, propranolol (20 mg kg(-1) per day). Salbutamol-induced muscle hypertrophy was associated with an increase in serum, skeletal-muscle and heart levels of the naturally occurring polyamines putrescine, spermidine and spermine. These observations suggest the involvement of polyamines in muscle hypertrophy and the possible role of blood polyamines as exposure biomarkers in beta-adrenergic-muscle hypertrophy.

Adrenergic beta-Agonists↗
PubMed1998

[Survey of sexually transmitted diseases in the region of Rio Cuarto].

Sexually transmitted diseases (STD) are acquired mainly through sexual intercourse, being one of the most frequent groups of infectious diseases worldwide and consequently an important public health problem. The aim of this paper was to determine the current state of STD and to compare different diagnostic methods in the population studied. A total of 1060 samples from vaginal flows, endocervical material and urethral discharge were studied during 3 years. Of the total samples, 583 were positive, 493 in women and 90 in men. Microorganisms found in women were: Gardnerella vaginalis (39.3%), Candida albicans (21.1%), Trichomonas vaginalis (17.3%), Candida trachomatis (11.3%), Neisseria gonorrhoeae (3.2%): Mycoplasma hominis and Ureaplasma urelyticum (6.5%) and Treponema pallidum (1.4%), the associations found were, Gardnerella vaginalis with Trichomonas vaginalis 5.5%; Gardnerella vaginalis with Candida albicans 4.9%; Trichomonas vaginalis with Neisseria gonorrhoeae (2.2%) and Gardnerella vaginalis with Chlamydia trachomatis (1.9%). In men, gonococcal urethritis (UG) represented 37.7% non UG 55.6% and Treponema pallidum 6.7%. These results indicate a decrease in sifilis and in UG when compared to previous studies showing that gonococcal cervicitis had also decreased. We found an important increase in the prevalence of urethritis and non gonococcal cervicitis in agreement with world statistics which consider these diseases as the most common venereal ones. It is necessary to increase the search for Chlamydia trachomatis in pregnant women due to vertical transmission. It should be noted that, in spite of certain fluctuations, the incidence of the STD in our area is still unacceptably high.

Adolescent↗