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Biomedical subjects

E Navarro

Publications and source records attributed to E Navarro.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effects of alpha-tocopherol, beta-carotene and ascorbic acid on oxidative, hormonal and enzymatic exercise stress markers in habitual training activity of professional basketball players.

BACKGROUND: Intense physical exercise has been associated with an increase of free radical production. When the body's natural defense systems against free radicals are overwhelmed, oxidative stress increases. AIM OF THE STUDY: This study examined the effects of a vitamin antioxidant supplement, (composed of 600 mg alpha-tocopherol, 1000 mg ascorbic acid and 32 mg beta-carotene) on oxidative, hormonal, and enzymatic exercise stress markers during habitual training activity over 35 days. METHODS: The plasma concentrations of ascorbic acid, alpha-tocopherol, beta-carotene, testosterone, cortisol and lipid peroxides and the serum activities of lactate dehydrogenase and creatine kinase were measured at four time points: pre-supplementation (PS), pre-training (PT), after training (AT) and 24 h after training (24h-AT) in 13 professional basketball players of the first Spanish Basketball League (ACB). RESULTS: Antioxidant supplementation led to a significant increase of alpha-tocopherol and beta-carotene from PS to PT. Plasma lipid peroxides decreased about 27.7% after 35 days of antioxidant treatment. A significant decrease of lactate dehydrogenase serum activity was observed during the 24 h recuperation time. During this time the anabolic/catabolic balance increased about 29.8% in the antioxidant supplemented group, although this increase did not reach statistical significance. CONCLUSIONS: The results of the present study suggest that supplementation with alpha-tocopherol, beta-carotene and ascorbic acid might partially account for the hormonal and enzymatic stress marker profile observed during habitual training activity of professional basketball players.

Adult↗
PubMed2001

A negative regulator of light-inducible carotenogenesis in Mucor circinelloides.

Mucor circinelloides responds to blue light by activating carotene biosynthesis. Wild-type strains grown in darkness contain minimal amounts of beta-carotene because of the low levels of transcription of the structural genes for carotenogenesis. When exposed to a light pulse, the level of transcription of these genes increases strongly, leading to the formation of high concentrations of beta-carotene. The crgA gene is involved in the regulation of light-induced carotenoid biosynthesis. This gene, originally identified as a 3'-truncated ORF which causes carotene over-accumulation in the dark, encodes a protein with a cysteine-rich, zinc-binding, RING-finger motif, as found in diverse groups of regulatory proteins. The expression of the crgA gene is activated by a light pulse, with a time course similar to that of the structural genes for carotenogenesis. To understand the regulatory role of the crgA gene in carotenogenesis, we have used a genetic approach based on the construction of crgA null mutants by gene replacement. Lack of the crgA function provokes the over-accumulation of carotenoids both in the dark and the light. Introduction of the wild-type crgA allele into these mutants restores the wild-type phenotype for carotenogenesis. The high levels of carotenoid accumulation shown by the null crgA mutants are correlated with an increase in the expression of carotenogenic structural genes. These results strongly indicate that crgA acts as a negative regulator of light-inducible carotenogenesis in M. circinelloides.

Carotenoids↗
PubMed2001

A cytotoxic diarylheptanoid from Viscum cruciatum.

A diarylheptanoid, 1,7-di-(3',4'-dihydroxyphenyl)-4-hepten-3-one, hirsutanone, has been isolated from the methanolic extract of the aerial parts of Viscum cruciatum (Viscaceae) and characterized by spectroscopic methods and chemical transformations. This compound showed cytotoxic activity against melanoma (UACC-62), renal (TK-10) and breast (MCF-7) cancer cell lines.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Efficacy and safety of clozapine and olanzapine: an open-label study comparing two groups of Parkinson's disease patients with dopaminergic-induced psychosis.

Clozapine, an atypical neuroleptic agent, improves dopaminergic-induced psychosis in parkinsonian patients without increasing motor disability. However, because of the risk of agranulocytosis periodic hematological controls are mandatory. Olanzapine, another atypical neuroleptic, does not require such monitoring, which may represent a practical advantage. Therefore, for 12weeks we compared the tolerability and efficacy of clozapine and olanzapine in two groups of nine consecutive parkinsonian psychotic patients treated with these compounds. All the patients on clozapine (mean starting dose: 13.1+/-7.9mg/d) completed the study despite reporting a number of adverse events, including somnolence, falls, orthostatic hypotension, and syncope. In contrast, early withdrawal occurred in three of the nine patients receiving olanzapine, due to severe gait deterioration and drowsiness (mean starting dose: 3.9+/-1.3mg/d). Psychotic symptoms improved in both groups, as reflected by a reduction of 71.7% in clozapine and a 61.7% reduction in olanzapine, in five selected items from the Neuropsychiatric Inventory. On conclusion of the study, parkinsonism had improved in the clozapine group with a 19.7% decrease in the raw scores and a 7.9% decrease in the weighted scores according to the Cornell University Rating Scale for parkinsonism (mean dose: 16.9+/- 10.3mg/d). Conversely, the six patients receiving olanzapine who finished the study experienced aggravated parkinsonian symptoms, with a 25.5% worsening in the raw scores and a 24.6% worsening in the weighted scores (mean dose: 4.7+/-2.3mg/d). We postulate that the early drop-outs in the olanzapine-treated parkinsonian group may be attributable to a non-specific effect of the drug as a result of starting at too high a dose, and that the worsening of parkinsonism following prolonged treatment may have been caused by the drug's blocking effect on striatal D2 receptors.

Journal Article↗
PubMed2001

General behavior, toxicity, and cytotoxic activity of elenoside, a lignan from Justicia hyssopifolia.

Cytotoxicity, acute toxicity, and general pharmacological effects in mice of an arylnaphthalene lignan isolated from Jisticia hyssopifolia were studied. Elenoside was cytotoxic to human cancer cell lines in a range of concentrations from 10(-5) to 10(-4)M. It has an LD(50), ip in mice, of 305 mg/kg and central depressive properties at doses of 25, 50, and 100 mg/kg. Thus, elenoside appears to be a sedative with broad spectrum cytotoxicity.

Animals↗
PubMed2001

Pharmacological effects of elenoside, an arylnaphthalene lignan.

Acute toxicity (24 h) and general behavior in mice of a lignan from Justicia hyssopifolia, a beta-D-glucoside (elenoside), was studied, and the cytotoxic activity was performed. Elenoside (arylnaphthalene lignan) in mice showed a moderate toxicity order (305 mg/kg) and central depressive properties at doses of 25, 50, and 100 mg/kg. It also displayed cytotoxic activity in a range of concentration of 10(-5)-10(-4) M when studied in the human tumor cell line panel of the US National Cancer Institute (NCI). The results indicated that elenoside has central depressant effects, and the cytotoxic activity of elenoside suggests that this compound and its genin derivatives merit further investigation as antitumoral drugs.

Animals↗
PubMed2000

Acute and acclimated digestive responses of the cockle Cerastoderma edule (L.) to changes in food quality and quantity. I. Feeding and absorption of biochemical components.

Cockles Cerastoderma edule were fed two different concentrations ( approximately 0.8 and 2 mm(3) l(-1)) of two diets with different qualities ( approximately 10 and 60% of organic content) which were achieved by mixing different proportions of ashed silt particles with cells of the microalgae Tetraselmis suecica. Clearance, ingestion and absorption rates of organic matter and biochemical components were measured after 3 days (acute response) and 11 days (acclimated response) of exposure to the diets. With low quality diets cockles were found to reject part of the filtered matter ( approximately 25-35%) through pseudofaeces production both in the acute and acclimated responses. In the acute response, absorption rate of organic matter was positively dependent on food quality and quantity, but the physiological response to increasing food concentrations differed with food quality: with low qualities, increasing absorption rate resulted from the simultaneous increase of clearance ( approximately 2 times) and ingestion rate ( approximately 4 times) as well as absorption efficiency of organic matter ( approximately 22%). However, those fed high qualities, were found to compensate increasing food concentration by reducing ( approximately 50%) clearance rate. The resulting moderate increase of ingestion rate ( approximately 1.6 times) was accompanied with a reduction in absorption efficiency ( approximately 20%). Irrespective of food quality and quantity, protein and lipids were absorbed, respectively, with the highest (from 61.7 to 80.0%) and the lowest (from 42.6 to 66.8%) efficiency. Acclimated response was entirely affected by food quality: with low qualities, cockles greatly improved the energetic intake from available ration ( approximately 4 and 2 times, with low and high food concentrations, respectively). Both preingestive and digestive mechanisms were involved in this response: at the preingestive level, clearance rate and preingestive selection efficiency were significantly increased. At the digestive level, cockles were capable of maintaining absorption efficiency of organic matter with rising ingestion rate. On the contrary, acclimation to high quality diets brought about no significant increase in organic absorption rate: with low ration, clearance rate was kept constant, whereas with high ration the increase in clearance and ingestion rate ( approximately 2 times) promoted a compensatory reduction in absorption efficiency. However, the biochemical composition of the absorbed matter was found to be absolutely modified, both at low and high food rations, due to an strong reduction of lipid absorption efficiency. The observed modifications of absorption rate and/or the biochemical composition of the absorbed matter suggests the capability of cockles to adjust the digestive performance.

Journal Article↗
PubMed2000

Behavioral despair in mice after prenatal stress.

Maternal stress during pregnancy produced behavioral alterations in both sexes with regard to sexual behavior, aggressive, maternal, lateralization and depression. In the present paper, sex differences for depression in mice was studied. No sex differences between female and male mice groups were observed either in swimming-induced immobility or in the open-field test (ambulation, rearing and boluses). Prenatal stress produced: 1) an increase of immobility time in female mice for swimming-induced immobility, but not in male mice; 2) an increase of ambulation in female mice for open-field test, but not in male mice; 3) there were no significant differences in rearing and boluses between stress and control groups either for female or male mice. Prenatal stress increases the risk of depression and locomotor activity in adult female mice.

Animals↗
PubMed2000

Cardiovascular activity of a methanolic extract of Digitalis purpurea spp. heywoodii.

The paper deals with the effects of a glycosidal extract of Digitalis heywoodii, ssp. of Digitalis purpurea L., (Schrophulariaceae) grown in Badajoz (Spain), on isolated cardiac auricle of rabbits, urinary excretion of rats, as well as its emetic effect in pigeons. These effects using vehicle (propylene glycol-ethanol-water, 40:10:50) and digoxin as standards are presented. The extract at concentrations of 20 and 40 microg/ml produced an increase in the contraction force of auricles in a dose-dependent way. At doses of 15 and 30 mg/kg a slight diuretic and natriuretic effect was observed. The active dose range for emesis was 0.5-4 mg/kg and a decrease of the emesis time within 10 min of injection in dose-dependent manner was obtained. The pharmacological activity of the extract is related to gitoxin derivatives (digitalinum verum and strospeside), the most abundant compounds obtained from the leaves of Digitalis purpurea spp. heywoodii.

Animals↗
PubMed2000

Overexpression of the crgA gene abolishes light requirement for carotenoid biosynthesis in Mucor circinelloides.

This work describes the isolation and characterization of crgA, a Mucor circinelloides gene, which has a dominant-positive effect on light-regulated carotenogenesis. The crgA gene was originally identified in a transformation experiment as a 3'-truncated open reading frame which caused carotenoid overaccumulation in the dark. The complete cloning and sequencing of crgA revealed that its putative product presented several recognizable structural domains: a RING-finger zinc binding domain near the N-terminus, a putative nuclear localization signal, two stretches of acidic amino acids, glutamine-rich regions and a putative isoprenylation motif. The expression of exogenous copies of the complete crgA gene or two different 3'-truncated versions, produced a similar dominant-positive effect on the light-inducible carotenogenesis of M. circinelloides. The presence of these exogenous sequences also caused a missregulation of the endogenous crgA gene, resulting in its overexpression. Collectively, these observations suggest that crgA is involved in the regulation of carotenoid biosynthesis by light.

Amino Acid Sequence↗
PubMed2000

Randomized comparative trial of triflusal and aspirin following acute myocardial infarction.

AIMS: To compare the efficacy and tolerability of the antiplatelet agent triflusal with aspirin in the prevention of cardiovascular events following acute myocardial infarction. METHODS AND RESULTS: In this double-blind, multicentre, sequential design study, patients were randomized within 24 h of acute myocardial infarction symptom onset to receive triflusal 600 mg or aspirin 300 mg once daily for 35 days. The primary end-point was death, non-fatal myocardial reinfarction or a non-fatal cerebrovascular event. The incidences of these individual outcomes and urgent revascularization were secondary end-points. The null hypothesis of no difference between treatments in the primary combined end-point was accepted with 80% power after recruiting 2124 validated patients (odds ratio (OR) for failure [95% confidence interval (CI)]: 0.882 [0.634-1.227]). Non-fatal cerebrovascular events were significantly less frequent with triflusal (OR [95% CI]: 0.364 [0.146-0.908]; P = 0.030). There was no significant difference between treatments for death (OR [95% CI]: 0.816 [0.564-1.179]; P = 0.278), non-fatal reinfarction (OR [95% CI]: 1.577 [0.873-2.848]; P = 0.131) or revascularization (OR [95% CI]: 0.864 [0.644-1.161]; P = 0.334). Overall, both drugs were well tolerated, although there was a trend towards fewer bleeding episodes with triflusal; significantly fewer central nervous system bleeding episodes were observed in triflusal-treated patients (0.27% vs. 0.97%; P = 0.033). CONCLUSION: Triflusal and aspirin have similar efficacy in preventing further cardiovascular events after acute myocardial infarction, but triflusal showed a more favourable safety profile. Triflusal significantly reduced the incidence of non-fatal cerebrovascular events compared with aspirin.

Aged↗
PubMed2000

Nutrition antioxidant status and oxidative stress in professional basketball players: effects of a three compound antioxidative supplement.

Professional basketball players of the First Spanish League (ACB) are highly trained athletes performing high training loads and competition sessions. As intense physical activity has been suggested to increase free radical production, we examined the effects of a vitamin antioxidant mixture on the degree of oxidative stress in these athletes. Subjects received either 600 mg alpha-tocopherol, 1,000 mg vitamin C and 32 mg beta-carotene, or a placebo over 32 days during a regular competition season. Plasma concentrations of alpha-tocopherol, vitamin C, beta-carotene, retinol, lipoperoxides (LPO), and the total antioxidant status (TAS) were analysed before and after treatment. Lipoperoxide plasma levels decreased significantly (p < 0.05) in the vitamin antioxidant supplemented group. The LPO/TAS ratio decreased about 15.3% in this group indicating a reduction in oxidative stress. Vitamin C dropped dramatically (p < 0.03, mean 15.4 micromol/L) in the placebo group leading to a marginal plasma vitamin C concentration (from 11 to less than 28 micromol/L). The results of this study suggest that the administered vitamin antioxidant mixture decreases oxidative stress and avoids the development of a marginal vitamin C status in professional basketball player during habitual training.

Adult↗
PubMed2000

Improving quality of expressed sequence tag (EST) databases: recovery of reversed, antisense cDNA sequences.

Expressed sequence tag (EST) databases contain a significant number (5-20%) of reversed, antisense, cDNA sequences that can be recognized by the label "reversed clone: similarity on wrong strand" in the annotations to the sequence. Despite this high number of altered sequences, no attempt has been made to explain the alteration in molecular terms, or to evaluate their effect on the quality of the information curated in EST databases. In this paper we try to explain the way these altered sequences are originated, and propose a plausible mechanism: a "double priming" of the first strand oligo-dT primer at both ends of nascent cDNAs. In this way, a symmetrical cDNA intermediate is generated, an intermediate that can be cloned after partial digestion with the restriction enzyme used for the directional cloning. Furthermore, when "secondary" priming takes place inside the cDNA, the chain synthesized is prone to be truncated prematurely, with the subsequent loss of upstream information. One of the most subtle effects of this cloning alteration is the generation of virtual open reading frames (ORFs) in sequences with no homologues available for comparison. Nevertheless, and according to our model and our data, the "double priming mechanism" does not shift the ORF effected, so antisense sequences should be considered as normal ones after a simple transformation in their inverse-complementary forms.

Artifacts↗
PubMed2000

Effect of olive oil on early and late events of colon carcinogenesis in rats: modulation of arachidonic acid metabolism and local prostaglandin E(2) synthesis.

BACKGROUND: Animal model studies have shown that the colon tumour promoting effect of dietary fat depends not only on the amount but on its fatty acid composition. With respect to this, the effect of n9 fatty acids, present in olive oil, on colon carcinogenesis has been scarcely investigated. AIMS: To assess the effect of an n9 fat diet on precancer events, carcinoma development, and changes in mucosal fatty acid composition and prostaglandin (PG)E(2) formation in male Sprague-Dawley rats with azoxymethane induced colon cancer. METHODS: Rats were divided into three groups to receive isocaloric diets (5% of the energy as fat) rich in n9, n3, or n6 fat, and were administered azoxymethane subcutaneously once a week for 11 weeks at a dose rate of 7.4 mg/kg body weight. Vehicle treated groups received an equal volume of normal saline. Groups of animals were colectomised at weeks 12 and 19 after the first dose of azoxymethane or saline. Mucosal fatty acids were assessed at 12 and 19 weeks. Aberrant crypt foci and the in vivo intracolonic release of PGE(2) were assessed at week 12, and tumour formation at week 19. RESULTS: Rats on the n6 diet were found to have colonic aberrant crypt foci and adenocarcinomas more often than those consuming either the n9 or n3 diet. There were no differences between the rats on the n9 and n3 diets. On the other hand, administration of both n9 and n3 diets was associated with a decrease in mucosal arachidonate concentrations as compared with the n6 diet. Carcinogen treatment induced an appreciable increase in PGE(2) formation in rats fed the n6 diet, but not in those fed the n3 and n9 diets. CONCLUSIONS: Dietary olive oil prevented the development of aberrant crypt foci and colon carcinomas in rats, suggesting that olive oil may have chemopreventive activity against colon carcinogenesis. These effects may be partly due to modulation of arachidonic acid metabolism and local PGE(2) synthesis.

Adenocarcinoma↗
PubMed2000

Abnormal fatty acid pattern in rheumatoid arthritis. A rationale for treatment with marine and botanical lipids.

OBJECTIVE: To assess the fatty acid pattern in plasma and synovial fluid (SF) in rheumatoid arthritis (RA) and to determine clinical factors related to possible abnormalities. METHODS: Thirty-nine patients with RA were included. SF samples were obtained from 9 patients. Disease activity was assessed using the Ritchie Articular Index and erythrocyte sedimentation rate. Fatty acids were assayed with gas liquid chromatography. RESULT: Decreased levels of eicosapentaenoic acid (p < 0.0001) and total n3 polyunsaturated fatty acids (p < 0.05) were observed in plasma and in joint fluid, respectively. An increase of the substrates of delta-5-desaturase (C20:3n6 and C20:2n6) and decrease of their products (C20:4n6 and C22:4n6) was observed in plasma total lipids and phospholipids. The long chain mono-unsaturated fatty acids (C20: 1n9, C22: 1n9, C24: ln9) were increased in the joint fluid and in plasma phospholipids. Patients with active disease showed a mild decrease of several saturated fatty acids, n3, and n6 polyunsaturated fatty acids. Minor abnormalities or no changes in fatty acid profile were found related to use of steroids, nonsteroidal antiinflammatory drugs, and gold salts, or malnutrition. CONCLUSION: The fatty acid pattern found in RA (decreased levels of n3 polyunsaturated fatty acids) may explain the beneficial effect of fish oil. Changes in n6 polyunsaturated fatty acids suggest that delta-5 desaturation is decreased and this might facilitate the antiinflammatory effect of botanical lipids in RA.

Aged↗
PubMed2000

[Validity of the Cognitive Mini-Exam of Lobo et al. for the detection of dementia-associated cognitive deterioration] .

BACKGROUND AND OBJECTIVES: The Mini-Examination Cognitive (MEC) of Lobo et al is widely used as a screening tool for dementia in epidemiological studies and in clinical context for the rapid evaluation of cases in whom there is a suspicion of cognitive deterioriation due to dementia. Nevertheless, the validity analysis in old people have not been accomplished. The objective of this study has been to validate the use of this instrument to detect cognitive deterioration associated with dementia in elderly people. PATIENTS AND METHODS: Ninety-five old people have participated, one group of patients of a Neurology Service and another group of healthy old people. All of them have been evaluated through a neuropsychological exploration protocol and the MEC. RESULTS: The results show a high validity of this test for the evaluation of the cognitive deterioration in this population, as in the correlation with the neurological tests used as in the ANOVA intergroups (with and without deterioration) executed; they also reflect the influence on the puntuations of variables such as the age and the educational level. CONCLUSIONS: The utility of this procedure for the Spanish population with a low cultural level and the necessity of working with different criteria depending on the age and the educational level of the patients evaluated is shown here.

Aged↗
PubMed1999

Expressed sequence tag (EST) phenotyping of HT-29 cells: cloning of ser/thr protein kinase EMK1, kinesin KIF3B, and of transcripts that include Alu repeated elements.

To study the mechanisms that control epithelial commitment and differentiation we have used undifferentiated HT-29 colon cancer cells and a subpopulation of mucus secreting cells obtained by selection of HT-29 cells in 10-6 M methotrexate (M6 cells) as experimental models. We isolated cDNAs encoding transcripts overexpressed in early confluent M6 cells regarding steady-state levels in HT-29 cells by subtractive hybridisation. Fifty-one cDNA clones, corresponding to 34 independent transcripts, were isolated, partially sequenced by their 5' end, and classified into four groups according to their identity: transcripts that included a repeated sequence of the Alu family (10 clones, among them those encoding ribonucleoprotein RNP-L and E-cadherin), transcripts encoded by the mitochondrial genome (nine clones), transcripts encoding components of the protein synthesis machinery (23 clones, including the human ribosomal protein L38 not previously cloned in humans) and nine additional cDNAs that could not be classified in the previous groups. These last included ferritin, cytokeratin 18, translationally controlled human tumour protein (TCHTP), mt-aldehyde dehydrogenase, as well as unknown transcripts (three clones), and the human homologues of the molecular motor kinesin KIF3B and of the ser/thr protein kinase EMK1. Spot dot and Northern blot analyses showed that ser/thr protein kinase EMK1 was differentially expressed in M6 cells when compared with parental HT-29 cells. Steady-state levels of EMK1 were higher in proliferating, preconfluent, M6 and HT-29 cells than in 2 days post confluence (dpc) and 8dpc M6 and HT-29 cells. Transcripts that included an Alu repeat were also shown to be differentially expressed and accumulated in differentiating M6 cells when analysed by Northern blot. The significance of the transcripts cloned is discussed in the context of the commitment and differentiation of the M6 cells to the mucus secreting lineage of epithelial cells.

Alu Elements↗