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Biomedical subjects

M Moreno

Publications and source records attributed to M Moreno.

At least 19 recordsLinked to original sources
PubMed2006

Long-term evolution of serum and liver viral markers in patients treated for chronic hepatitis C and sustained response.

Few studies have analysed the evolution of HCV markers in chronic hepatitis C (CHC)-treated patients. We have evaluated the presence or absence of serum and liver HCV-RNA, the core antigen (HCV-cAg) and the loss of specific antibodies (anti-HCV), in long-term sustained responders (SR). One hundred and seventy-six patients (132 SR and 44 nonresponders (NR) were included in the study. HCV-RNA was determined in serum and liver by a commercial PCR-kit. HCV-Ag was determined by ELISA and specific antibodies against HCV by means of a commercial line immunoblot assay (LIA) technique. Serum HCVcAg was found positive in three (4.2%) SR and in one (4%) NR (NS). Four SR (3.6%) and 44 NR (100%) were also HCV-RNA (+) in liver tissue. Two patients were HCV-cAg (+). A good correlation was found between the serum levels of HCV-cAg and HCV-RNA (r = 0.847, P < 0.001). Specific antibodies (anti-HCV) were determined by LIA in 45 patients. A decrease was found in the number of patients who presented reactivity to bands E2 and NS4 when we compared SR with a follow-up of more than 5 years with NR and SR with a follow-up <5 years (P < 0.01 and 0.005). A good correlation was found between the HCV-cAg and HCV-RNA serum levels in CHC-treated patients (P < 0.001). Few SR (3.6%) had HCV-RNA in the liver, and HCV-cAg (1.8%) in serum. In SR with more than 5 years of follow-up a clear tendency exists in the trend to clarify the bands E2 and NS4 of anti-HCV in serum.

Adult↗
PubMed2005

Determination of amitrole and urazole in water samples by capillary zone electrophoresis using simultaneous UV and amperometrical detection.

In this paper, capillary zone electrophoresis with amperometric detection (CZE-AD) was first applied to the simultaneous separation and determination of amitrole and urazole in water samples. A simple end-column electrochemical detector was used in combination with a commercially available capillary electrophoresis instrument with UV detection. The effects of several important factors were investigated to find optimum conditions. A carbon disk electrode was used as working electrode. Separation and determination of these compounds in water samples were performed in 0.030 mol l(-1) acetate buffers at pH 4.5, 25 kV as separation voltage and the samples were introduced by hydrodynamic mode for 1.5 s. Most of the studies realized showed that the direct electrochemical detection is more sensitive and selective than UV detection. Under the optimum conditions, excellent linearity was observed between peak amperometric signal and analyte concentrations in the range of 0.19-1.35 mg l(-1) for amitrole and 0.20-1.62 mg l(-1) for urazole. The detection limits were 63 and 68 microg l(-1) for amitrole and urazole, respectively. The utility of this method was demonstrated by monitoring water samples, and the assay results were satisfactory. The detection limits using a previous preconcentration step for amitrole and urazole in spiked mineral water samples were 0.6 and 1.0 microg l(-1) for amitrole and urazole, respectively.

Amitrole↗
PubMed2005

Polarization of valence band holes in the (Ga,Mn)as diluted magnetic semiconductor.

We report on direct measurements of the impurity band hole polarization in the diluted magnetic semiconductor (Ga,Mn)As. The polarization of impurity band holes in a magnetic field is strongly enhanced by antiferromagnetic exchange interaction with Mn ions. The temperature dependence of the hole polarization shows a strong increase of this polarization below the Curie temperature. We show that the ground state of the impurity band is formed by uniaxial stress split F=+/-1 states of antiferromagnetically coupled Mn ions (S=5/2) and valence band holes (J=3/2). The gap between the Mn acceptor related impurity band and the valence band is directly measured in a wide range of Mn content.

Journal Article↗
PubMed2005

Thyroid-hormone effects on putative biochemical pathways involved in UCP3 activation in rat skeletal muscle mitochondria.

In vitro, uncoupling protein 3 (UCP3)-mediated uncoupling requires cofactors [e.g., superoxides, coenzyme Q (CoQ) and fatty acids (FA)] or their derivatives, but it is not yet clear whether or how such activators interact with each other under given physiological or pathophysiological conditions. Since triiodothyronine (T3) stimulates lipid metabolism, UCP3 expression and mitochondrial uncoupling, we examined its effects on some biochemical pathways that may underlie UCP3-mediated uncoupling. T3-treated rats (Hyper) showed increased mitochondrial lipid-oxidation rates, increased expression and activity of enzymes involved in lipid handling and increased mitochondrial superoxide production and CoQ levels. Despite the higher mitochondrial superoxide production in Hyper, euthyroid and hyperthyroid mitochondria showed no differences in proton-conductance when FA were chelated by bovine serum albumin. However, mitochondria from Hyper showed a palmitoyl-carnitine-induced and GDP-inhibited increased proton-conductance in the presence of carboxyatractylate. We suggest that T3 stimulates the UCP3 activity in vivo by affecting the complex network of biochemical pathways underlying the UCP3 activation.

Animals↗
PubMed2005

Fungal communities in PAH-impacted sediments of Genoa-Voltri Harbour (NW Mediterranean, Italy).

Organic matter (in terms of carbohydrates and proteins), polycyclic aromatic hydrocarbons (PAHs) and bacterial density were investigated in the sediments of three stations in Genoa-Voltri Harbour (NW Mediterranean), and related to the sedimentary fungal community. Sites were significantly different in all investigated parameters (ANOVA, p<0.05), and a sharp gradient of impact in the area was found. All the 81 strains of filamentous fungi isolated, belonging to 7 genera, appeared to be linked with PAHs (p<0.05; r=0.95), whereas bacterial density was positively correlated with organic matter content (p<0.05; r=0.98). Within the fungal community, strains with a high capability to degrade xenobiotics were found. Among the genera identified, Penicillium, Mucor and Cladosporium showed the highest frequency in the sites where the heaviest concentrations of PAHs were recorded. This study suggests that fungal communities are important for in situ degradation of xenobiotics in impacted sediments.

Analysis of Variance↗
PubMed2005

Antennal phenotype of Triatoma dimidiata populations and its relationship with species of phyllosoma and protracta complexes.

Triatoma dimidiata (Latreille 1811) Reduviidae Triatominae is the main vector of Chagas disease in several countries of Latin America. As for other vector species, the characterization of T. dimidiata subpopulations within particular geographical regions or occupying different habitats could help in better planning of vector control actions. A first objective in this study was to evaluate the antennal phenotype as a phenetic marker to characterize populations of T. dimidiata collected in different geographic areas and domestic and sylvatic habitats. A second objective was to evaluate the phenetic relationships of T. dimidiata with other species of the phyllosoma complex: longipennis, pallidipennis, and phyllosoma. The antennal sensilla of T. dimidiata specimens collected in Mexico, Central America, and Colombia were analyzed and compared with the antennal sensilla of T. longipennis, T. pallidipennis, and T. phyllosoma. T. barberi was used as an outgroup in the analysis. For each specimen, the ventral side of the three distal segments of the antennae was drawn, identifying and counting four types of sensilla. In T. dimidiata, univariate and multivariate analysis showed differences between sexes, among populations collected in different habitats within the same region, and among populations collected in different geographic regions. Two types of antennal sensilla showed a latitudinal variation. Domestic specimens showed intermediate characteristics of the antennal phenotype, between sylvatic cave- and sylvatic forest-collected specimens. The antennal phenotypes show high similarities among T. pallidipennis, T. phyllosoma, and T. longipennis, with a better differentiation of T. pallidipennis. T. dimidiata is separated from the other members of the complex by a similar distance to T. barberi, of the protracta complex.

Animal Structures↗
PubMed2005

Long-term behavioural and neuroendocrine effects of perinatal activation or blockade of CB1 cannabinoid receptors.

The present work studied the long-term effects of chronic perinatal manipulation of cannabinoid CB1 receptors in male and female rats. Perinatal activation of cannabinoid CB1 receptors by chronic administration of delta9-tetrahydrocannabinol at different doses (0.1, 0.5, 2 mg/kg, p.o.) induced sexually dimorphic behavioural changes in adulthood, altering habituation of locomotion, immobility and exploratory activity. These behavioural effects were also accompanied by alterations in corticosterone levels in the adult period. Prenatal blockade of CB1 receptors by chronic administration of 3 mg/kg (s.c.) of SR141716A decreased immobility behaviour in male and female animals, without any significant changes in corticosterone plasma levels. Cannabinoid CB1 receptors appear to play an important role in the ontogeny of psychomotor behaviours, and activation or blockade of these receptors during stages of plasticity, such as the prenatal or perinatal periods, can induce long-term effects, as shown by sexually dimorphic changes in behavioural patterns in adulthood.

Adrenocorticotropic Hormone↗
PubMed2005

Behavioural effects of quinpirole following withdrawal of chronic treatment with the CB1 agonist, HU-210, in rats.

The present study investigated spontaneous and quinpirole-induced motor responses of in rats, following withdrawal from chronic treatment with the potent cannabinoid agonist HU-210. Withdrawal from chronic HU-210 (20 microg/kg daily, 14 days) produced a decrease in spontaneous activity at 1 and 2 days and enhanced the hyperactivity induced by acute administration of the dopamine D2 agonist quinpirole (0.5 mg/kg) at 4 days after the end of HU-210 treatment. Administration of quinpirole on day 4 of withdrawal from chronic HU-210 enhanced stereotyped responses and induced jumping behaviour. These results suggest that withdrawal from chronic exposure to cannabinoid agonists could induce a time-dependent alteration in dopamine D2 psychomotor function, leading to a behavioural disorganization, comparable to acute psychotic episodes after continuous cannabinoids.

Animals↗
PubMed2005

Psychometric field study of the new haemophilia quality of life questionnaire for adults: the 'Hemofilia-QoL'.

Although there is a worldwide interest in the assessment of health-related quality-of-life (HRQoL) in haemophilia patients, no non-disease specific instruments (for adults) are readily available. In this paper, a haemophilia-specific quality-of-life assessment measure for adults (the Hemofilia-QoL questionnaire) has been developed and tested for psychometric properties in 121 adults with haemophilia living in Spain. The Hemofilia-QoL questionnaire is a self-report modular instrument that assesses nine relevant HRQoL domains for patients with haemophilia (e.g. physical health, daily activities, joint damage, pain, treatment satisfaction, treatment difficulties, emotional functioning, mental health, relationships and social activity). Psychometric examination involved the assessment of data quality, scaling assumptions, reliability (internal consistency and test-retest) and validity (concurrent; external clinical criterion and sensitivity). The Hemofilia-QoL 36-item version questionnaire had acceptable internal consistency and retest reliability values. The questionnaire shows excellent concurrent validity (with the SF-36 Health Survey) and external clinical criterion validity (haemophilia clinical status) and sensitivity (health status changes) as well. The Hemofilia-QoL is now available for adult assessment and is ready for use in clinical research in Spain.

Adolescent↗
PubMed2005

Effects of angiotensin converting enzyme inhibitors in hypertensive patients with aortic valve stenosis: a drug withdrawal study.

OBJECTIVE: To determine the effects of angiotensin converting enzyme (ACE) inhibitors in hypertensive patients with aortic valve stenosis (AS). DESIGN: Observational, drug withdrawal, single blinded study, with randomisation of the order of tests. SETTING: Hypertension and asymptomatic AS. PATIENTS AND INTERVENTIONS: 20 patients (aged 73 (9) years, valve area 0.7 (0.3) cm2, left ventricular ejection fraction > or = 45%) were enrolled. Each patient underwent two sets of tests (with and without taking the drug), each of which included clinical evaluation, Doppler echocardiogram, and symptom limited exercise echocardiography. MAIN OUTCOME MEASURES: Functional and haemodynamic variables while taking and not taking ACE inhibitors. RESULTS: Drug intervention induced no change in patients' subjective functional class. While taking ACE inhibitors, patients had a lower systolic blood pressure (140 (18) mm Hg with ACE inhibitors v 159 (12) mm Hg without ACE inhibitors, p = 0.02), a higher mean pressure gradient (34 (15) mm Hg v 28 (18) mm Hg, p = 0.037), and a higher left ventricular stroke work loss (19 (6)% v 14 (10)%, p = 0.009). Other baseline functional and haemodynamic parameters were unmodified. Five patients had an abnormal blood pressure response during one of the exercise tests (two patients while taking the drug and three patients while not taking the drug). When taking ACE inhibitors, patients had a higher stroke volume at peak stress (59 (11) ml v 54 (25) ml, p = 0.046). All other stress variables remained constant. CONCLUSIONS: In AS, the afterload relief caused by ACE inhibitors is blunted by a parallel increase in the pressure gradient. However, ACE inhibitors favourably affect stress haemodynamic function in most hypertensive patients with AS and should not be discontinued.

Aged↗
PubMed2005

Effects of a non-selective beta-blocker on adult rat anterograde axonal transport and retinal ganglion layer after increased intraocular pressure.

The aim of this study was to examine the effects of timolol in an experimental model of elevated intraocular pressure (IOP). Three episcleral veins of rats with normal IOP were cauterized. Three months later we examined the effects on anterograde axonal transport from the retinal ganglion cells (RGCs) to the superior colliculus (SC) as well as on the number of neurons in the retinal ganglion layer (RGL). These parameters were also studied in a group of rats submitted to treatment with timolol after confirming that their IOP was still raised after two weeks. After the surgical procedure, the mean IOP of the experimental eyes increased to 33.5+/-1.06 mmHg (1.25 fold compared to the control group) and three months later the IOP remained significantly elevated; however, after a long period of treatment with timolol the IOP was 14.05+/-0.81 mmHg, similar to that of the control group. In the group with normal IOP, labelling with horseradish rabbit peroxidase (HRP) at 120 minutes and 24 hours postinjection showed continuous staining from the retina to the SC. In the experimental group the optic nerve head (ONH) was completely negative, although in the group treated with timolol there was partial block of axonal transport in the ONH, in which the staining was slightly more intense. The number of neurons in the RGL, counted by immunohistochemical labelling with Neu-N, showed that in eyes with normal and elevated IOP there were 423+/-11 neurons/mm(2) and 283+/-10 neurons/mm(2), respectively. After treatment with timolol the number of neurons (331+/-10 cells/mm(2) increased compared with elevated IOP eyes, although the number did not reach that of the control group. These results indicate that treatment with timolol, started two weeks after the surgical procedure, was partially neuroprotective because the loss of neurons in the RGL was lower than in untreated animals, though not sufficient to re-establish normal axonal transport.

Adrenergic beta-Antagonists↗
PubMed2005

Long-term evolution of liver histopathology in patients with chronic hepatitis C and sustained response.

OBJECTIVE: To evaluate the evolution of histological changes observed in patients with chronic hepatitis C (CHC) and sustained response (SR) compared to non-responders (NR) to antiviral treatment. METHODS: A retrospective study was performed in a total of 176 patients with CHC. These were divided into two groups: 132 SR and 44 NR. All had undergone a basal liver biopsy prior to treatment onset. A second biopsy was performed in 143 patients, 104 SR and 39 NR. Inflammatory activity and the degree of liver fibrosis was measured by Metavir units (MU). The progression and regression index of fibrosis was calculated before and after treatment. The time elapsed between the two biopsies was 5.9 +/- 0.3 years for SR and 6.6 +/- 0.3 years for NR (NS). RESULTS: At baseline, 53% of SR patients had mild, chronic active hepatitis (CAH), while this was moderate in 43% of NR patients (p < 0.0001). The time elapsed between baseline and post-treatment liver biopsies was 5.9 +/- 0.3 years for SR subjects and 6.6 +/- 0.4 years for NR subjects (NS). After antiviral treatment 47% of SR subjects presented a normal liver or minimal changes, whilst mild CAH persisted in 34.4% and moderate CAH in 37.5% of NR subjects. Necro-inflammatory activity decreased by 50% in SR subjects and by 15% in NR subjects (p < 0.0001), and fibrosis decreased by 82% in SR subjects (p < 0.0001) and by 66% in NR subjects (p < 0.001). Fibrosis progression index was 0.14 MU/year in SR subjects and 0.21 MU/year in NR subjects (NS). Fibrosis regression index was -0.11 in SR subjects and -0.14 in NR subjects (NS). CONCLUSIONS: In our series of patients with CHC and SR, we observed histological normalization in approximately fifty per cent of cases during long-term follow-up. NR subjects also showed improvement, especially in the fibrosis score. Both groups showed a marked regression of liver fibrosis after treatment.

Adult↗
PubMed2004

Impurities in noncubic crystals: stabilization mechanisms for Jahn-Teller ions in layered perovskites.

Mechanisms responsible for the local geometry around Jahn-Teller impurities in K2NiF4 type lattices are shown to be different from those generating the warping in cubic crystals. The present density functional theory calculations reveal that the elastic anisotropy of the host lattice (visible for closed shell impurities) and the electric field created by the rest of lattice ions upon active electrons make it possible to have d(9) ions in an elongated geometry but with a A(1g) ground state. The puzzling difference between equilibrium geometries for Cu2+ and Ni+ in layered perovskites can reasonably be understood.

Journal Article↗
PubMed2004

Nanomechanics of the formation of DNA self-assembled monolayers and hybridization on microcantilevers.

Biomolecular interactions over the surface of a microcantilever can produce its bending motion via changes of the surface stress, which is referred to nanomechanical response. Here, we have studied the interaction forces responsible for the bending motion during the formation of a self-assembled monolayer of thiolated 27-mer single-stranded DNA on the gold-coated side of a microcantilever and during the subsequent hybridization with the complementary nucleic acid. The immobilization of the single-stranded DNA probe gives a mean surface stress of 25 mN/m and a mean bending of 23 nm for microcantilevers with a length and thickness of about 200 microm and 0.8 microm, respectively. The hybridization with the complementary sequence could not be inferred from the nanomechanical response. The nanomechanical response was compared with data from well-established techniques such as surface plasmon resonance and radiolabeling, to determine the surface coverage and study the intermolecular forces between neighboring DNA molecules anchored to the microcantilever surface. From both techniques, an immobilization surface density of 3 x 10(12) molecules/cm(2) and a hybridization efficiency of 40% were determined. More importantly, label-free hybridization was clearly detected in the same conditions with a conventional sensor based on surface plasmon resonance. The results imply that the nanomechanical signal during the immobilization process arises mainly from the covalent attachment to the gold surface, and the interchain interactions between neighboring DNA molecules are weak, producing an undetectable surface stress. We conclude that detection of nucleic acid hybridization with nanomechanical sensors requires reference cantilevers to remove nonspecific signals, more sensitive microcantilever geometries, and immobilization chemistries specially addressed to enhance the surface stress variations.

Base Sequence↗