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Biomedical subjects

E Vázquez

Publications and source records attributed to E Vázquez.

At least 19 recordsLinked to original sources
PubMed2000

Weaning induces an increase in the number of specific cytokine-secreting intestinal lymphocytes in mice.

Intestinal immunity differs from systemic immunity in several aspects and is frequently studied separately. In this work we have analysed the frequency of mononuclear cells spontaneously secreting the cytokines IL-2, IL-4, IL-5, IL-6, IL-10, interferon gamma (IFN-gamma) and tumour necrosis factor (TNF-alpha), in Peyer's patches and lamina propria of small intestine in mice by enzyme linked immunosorbent spot (ELISPOT) during 1 month after weaning. We have found a high percentage of spontaneous Th(1)as well as Th(2)cytokine-secreting lymphocytes in both populations, Peyer's patches and lamina propria. An increase in the number of the lymphocytes secreting most of the studied cytokines, at 1 and 2 weeks after weaning, was also observed. These results suggest that the increase in the number of cytokine secreting lymphocytes may be one of the potential mechanisms involved in the development of the intestinal immune system at weaning.

Animals↗
PubMed2000

Comparative toxicity of dissolved metals to early larval stages of Palaemon serratus, Maja squinado, and Homarus gammarus (Crustacea:Decapoda).

The acute lethal toxicities of mercury, copper, and cadmium to the first larval stage of the prawn (Palaemon serratus), spider crab (Maja squinado), and lobster (Homarus gammarus) were tested. Chromium was also tested with the prawn. Mortality was recorded after 48 h (for lobster) or 72 h (for other species) incubation at 18 degrees C, and the median lethal concentrations (LC(50) +/- 95% confidence intervals) per individual and per mass unit were calculated. The LC(50) values were, 74 microg Hg/L, 3,304 microg Cu/L, 1,686 microg Cd/L, 12,486 microg Cr/L for prawn; 72 microg Hg/L, 50 microg Cu/L, 158 microg Cd/L for spider crab; and 48 microg Hg/L, 46 microg Cu/L, 34 microg Cd/L for lobster. Therefore, larvae of spider crab and lobster were markedly more sensitive than prawn to heavy metals and thus more suitable to use in seawater quality bioassays. Of these two species, spider crab is recommended due to its abundance, easier maintenance, and higher fecundity. The mercury LC(50) values for different larval stages of P. serratus (zoea I, II, V, and VI) were obtained, and no ontogenetic change in sensitivity to the metal could be detected.

Animals↗
PubMed2000

Stability and folding of the protein complexes of barnase.

Native-like complexes of proteins, formed by the association of two complementary fragments comprising the entire sequence of the protein, can be used to gain insight into the stability and folding of the intact protein. We have studied the structural, thermodynamic and kinetic properties of four barnase complexes, with the cleavage site at different positions of the amino-acid chain (CB36, at position 36; CB56, at position 56; CB68, at position 68; and CB79, at position 79). The four barnase complexes have native-like structure as shown by fluorescence, far-and near-UV CD, size-exclusion chromatography and NMR. The NMR characterization indicated that the structural changes were mainly located in regions close to the cleavage site. The main core of the protein was fully formed and the overall structure was similar to that of intact barnase. The thermal and chemical denaturation showed that all complexes were substantially destabilized. CB56 displayed two denaturation transitions, probably because of the presence of partially folded conformations around the cleavage site. The rate constant for the association/folding of fragments decreased with the decreasing length of the C-terminal fragment. Thus, the larger the fragment (and, consequently, the larger the amount of residual native-like structure), the faster the association. These findings are consistent with the proposed model of barnase folding.

Bacterial Proteins↗
PubMed2000

Influence of atrial fibrillation on the morbido-mortality of patients on hemodialysis.

BACKGROUND: The consequences of atrial fibrillation (AF) on morbido-mortality of patients on hemodialysis have not been fully explored. The objective of this study was to determine the prevalence of AF in patients on hemodialysis and to evaluate its influence on the development of thromboembolic phenomena (TEP). METHODS: The incidence of AF in 190 patients in our hemodialysis program was assessed, and the patients were followed up for 1 year. Pertinent demographic and biochemical parameters were entered into univariate and multivariate statistical analyses to evaluate associations with overall mortality and TEP such as cerebrovascular accident, transitory ischemic accident, or peripheral embolism. RESULTS: In 13.6% of patients, AF was found; 9.4% of these were of the permanent type. In the multivariate analysis, only increased age was associated with a higher probability of having arrhythmia (odds ratio, 1.10; 95% confidence interval, 1.03-1.17; P =.003). During follow-up, 23% of the patients with AF died compared with 6% of those in sinus rhythm (P <.05), although AF did not appear to be an independent predictive factor for death. Thirty-five percent of the patients with AF and 4% with sinus rhythm had TEP (P <.01). In the multivariate analysis, AF was identified as the only independent predictor for TEP (odds ratio, 8; 95% CI, 2.3-27; P =.0008). CONCLUSIONS: AF is a frequent arrhythmia in patients on hemodialysis, and approximately 1 in 3 hemodialysis patients with AF had thromboembolic complications within 1 year of follow-up. These findings suggest that the consensus contraindication of prophylactic anticoagulation therapy for this group of patients may need to be redefined.

Adult↗
PubMed2000

Therapeutic effects of docosahexaenoic acid ethyl ester in patients with generalized peroxisomal disorders.

Generalized peroxisomal disorders are severe congenital diseases that involve the central nervous system, leading to severe psychomotor retardation, retinopathy, liver disease, and early death. In these disorders, peroxisomes are not normally formed and their enzymes are deficient. Characteristically, plasmalogen synthesis and beta-oxidation of very-long-chain fatty acids (VLCFAs) are affected. We found that patients with generalized peroxisomal disorders have a profound brain deficiency of docosahexaenoic acid (DHA; 22:6n-3) and low DHA concentrations in all tissues and the blood. Given the fundamental role of DHA in neuronal and retinal membranes, a DHA deficiency of this magnitude might be pathogenic. Thus, we studied the possible therapeutic effect of normalizing DHA concentrations in patients with peroxisomal disorders. We chose the DHA ethyl ester (DHA-EE) because of its high degree of purity at daily oral doses of 100-500 mg. This article summarizes the results of treatment of 13 patients with DHA-EE, with some follow-up evidence of clinical improvement. Supplementation with DHA-EE normalized blood DHA values within a few weeks. Plasmalogen concentrations increased in erythrocytes in most patients and after DHA concentrations were normalized, amounts of VLCFAs decreased in plasma. Liver enzymes returned almost to normal in most cases. From a clinical viewpoint, most patients showed improvement in vision, liver function, muscle tone, and social contact. In 3 patients, normalization of brain myelin was detected by magnetic resonance imaging. In 3 others, myelination improved. In a seventh patient, myelination is progressing at a normal rate. These results suggest a fundamental role of DHA in the pathogenesis of Zellweger syndrome. DHA therapy is thus strongly recommended, not only to alleviate symptoms in patients with life-threatening diseases, but also to clarify remaining questions regarding the role of DHA in health and disease.

Brain↗
PubMed2000

Murine CFTR channel and its role in regulatory volume decrease of small intestine crypts.

Cystic fibrosis (CF) is caused by mutations in the secretory Cl(-) channel CFTR (cystic fibrosis transmembrane conductance regulator). Variation in the severity of disease has been attributed to mutations in the CFTR gene that cause different degrees of dysfunction of the CFTR Cl(-) channel. However, studies of mouse models of CF indicate that the severity of intestinal pathology is not correlated with activity of the CFTR chloride channel. This observation suggests that other 'environmental' factors might be important in determining the severity of disease. In this respect, we have identified and characterised an additional cellular defect in intestinal epithelial cells of CF mice, the inability of these cells to regulate their volume after hypotonic challenge. Here, we review the function of murine CFTR as both a Cl(-) channel and as a regulator of volume-dependent homeostatic cell mechanisms.

Animals↗
PubMed1999

[Treatment of generalized peroxisomal disorders with docosahexaenoic acid ethyl ether].

INTRODUCTION: We found that patients with the Zellweger syndrome and other generalized peroxisomal disorders have a dramatic decrease of docosahexaenoic acid (DHA, 22:6n-3) in the blood, brain, retina and other tissues. DHA is believed to play an important role in the brain and retina. DEVELOPMENT: Patients with the Zellweger syndrome and its variants have severe cerebral and retinal defects that could be related to their DHA deficiency. With this rationale, we have been treating peroxisomal-disorder patients with a DHA derivative of a high degree of purity (DHA ethyl ester, > 90% pure) since 1991. So far, we have treated 13 DHA-deficient peroxisomal patients, one with the classic Zellweger syndrome and 12 with milder variants of the disease. This paper presents the follow-up of these DHA-treated patients. In summary, we have found important improvements in liver function, in the plasmalogen levels and in the two ratios 26:0/22:0 y 26:1/22:0, diagnostic of the disease. We have also found clear clinical improvements in most cases. Most significantly, magnetic resonance imaging has shown advances in brain myelination, so far in 6 of the treated patients. CONCLUSION: We strongly recommend treatment with DHA ethyl ester in all DHA-deficient patients with generalized peroxisomal disorders. Logically, treatment should be started as soon as possible, in the hope of preventing cerebral and visual damage.

Brain↗
PubMed1998

Is the malaria diagnosis expensive?

Malaria remains the most important of the tropical diseases, widespread throughout the tropics, but also occurring in many temperate regions. The disease causes a heavy toll of illness and death, among children in endemic areas. It also poses a risk to business travellers, tourists and immigrants and imported cases of malaria are increasingly seen in non-endemic areas. We discuss here how microscopical diagnosis is essential for identifying Plasmodium species responsible of the infection and discarding possible mixed infections. Thus, a correct treatment can be administered in 30 min, avoiding secondary stays and saving important amounts of money. Problems of drug resistance have to be distinguished from those arising due to erroneous diagnosis.

Adult↗
PubMed1998

Non-operative management of traumatic pancreatic pseudocysts associated with pancreatic duct laceration in children.

Objective. To assess the successful non-operative management in traumatic pancreatic pseudocysts (TPP) associated with duct laceration in children. Surgical therapy (cystogastrostomy or distal pancreatectomy with splenic salvage) has been classically considered the treatment of choice for those pseudocysts. Materials and methods. This report presents the clinical and imaging findings in two children with TPP and pancreatic duct disruption observed either on endoscopic retrograde cholangiopancreatography or injection via catheter drainage. Results. Both children responded to long-term cyst drainage. Conclusion. Although the experience is limited, the authors suggest that pancreatic injury associated with duct laceration can respond to non-operative management.

Adolescent↗
PubMed1998

Pediatric pancreas: an overview.

Pancreatic disorders are not rare in children. Modern imaging equipment allows recognition of many pancreatic diseases that were difficult to identify in the past and therefore were considered to be unusual. Within the scope of this article we include information on imaging modalities for studying the pancreas and a description of the radiologic manifestations of the most common congenital, inflammatory, tumoral, traumatic and systemic disorders.

Child↗
PubMed1998

[Infectious endocarditis caused by Leuconostoc mesenteroides].

BACKGROUND: Leuconostoc spp. are gram-positive coccobacilli, catalase and oxidase negative, vancomycin resistant, with a not clearly defined role in human infectious. Cases of infection have been reported previously but it has not been described confirmed infective endocarditis due to Leuconostoc mesenteroides. METHODS: We describe a case of prosthetic valve endocarditis in a 72-years-old woman with a long previous history of cardiac disease but without other immunological disorders. She developed a heart failure because of prosthetic aortic valve dysfunction. CONCLUSIONS: Leuconostoc mesenteroides should be considered as a potential cause of infective endocarditis and listed in the group of vancomycin-resistant microorganism.

Aged↗
PubMed1997

Expression of the cytoskeletal protein MAP5 and its regulation by neurotrophin 3 (NT3) in the inner ear sensory neurons.

Microtubule-associated proteins (MAPs) are essential cytoskeletal components during development for neurogenesis and neuronal plasticity. Inner ear innervation is accomplished by cochleovestibular ganglion (CVG) neurons in a highly specific, well-defined pattern, which is regulated by neurotrophic factors belonging to the neurotrophin family. The inner ear offers a suitable model for studying the expression of MAPs and assessing their role in neurotrophin-induced effects that are required for neuron-target innervation. The present study was undertaken to analyze the expression and localization of MAP5 isoforms during development of CVG neurons in vivo an in vitro; as well as the regulation of MAP5 by neurotrophin-3 (NT3) in cell culture. MAP5 expression in the inner ear of chick embryos and postnatal specimens was monitored using immunoblots and immunohistochemistry on frozen sections. MAP5 was highly expressed during the early stages of CVG development, at embryonic day (E)4, being located in both neuronal perikarya and neurites. Expression was maintained during the neurite outgrowth phase (E6-E12), when strong MAP5 immunostaining was observed at the same cellular locations. MAP5 expression decreased suddenly at E14, after the establishment of specific connections between the CVG neurons and their targets, the sensory epithelium of the inner ear. In cultured CVG neurons addition of NT3 led to increased MAP5 expression and produced neurite outgrowth. Both effects are differentially regulated in parallel by low (0.5 ng/ml) and high (5 ng/ml) NT3 concentrations. Present results suggest that MAP5 may be involved in neurotrophin-induced microtubule bundling during neurite outgrowth of auditory neurons.

Age Factors↗
PubMed1997

Presynaptic modulation of glutamate release targets different calcium channels in rat cerebrocortical nerve terminals.

We have studied which type/s of Ca2+-channel/s support glutamate exocytosis and its modulation by presynaptic receptors in cerebrocortical nerve terminals. Depolarization of nerve terminals with 30 mM KCl induced a Ca2+-dependent release of 3.64 +/- 0.25 nmol/mg of protein. The addition of either 2 microM omega-conotoxin-GVIA or 200 nM omega-agatoxin-IVA reduced the KCl-evoked release by 47.7 +/- 3.5% and 70.4 +/- 8.9% respectively, and by 85.7 +/- 4.1% when both toxins were co-applied. The activation of adenosine A1 receptors with N6-cyclohexyladenosine or the activation of metabotropic glutamate receptors with L(+)-2-amino-4-phosphonobutyrate inhibited the KCl-evoked release by 41.0 +/- 5.9 and 54.3 +/- 10% respectively. The extent of these inhibitions was not altered by the prior addition of 2 microM omega-conotoxin-GVIA but they were significantly enhanced when omega-agatoxin-IVA was added together with the adenosine A1 receptor agonist or the metabotropic glutamate receptor agonist, suggesting that omega-conotoxin-GVIA-sensitive and not omega-agatoxin-IVA-sensitive Ca2+-channels are involved in the action of these inhibitory receptors. By contrast, the facilitation of glutamate release that follows the activation of the protein kinase C, either with phorbol esters or with the stimulation of phospholipase C-linked metabotropic receptors, was expressed by both omega-conotoxin-GVIA-sensitive and omega-agatoxin-sensitive Ca2+-channels. It is concluded that different Ca2+-channels support the modulation of glutamate release by presynaptic receptors.

Adenosine↗
PubMed1997

Differential expression of microtubule associated protein MAP-2 in developing cochleovestibular neurons and its modulation by neurotrophin-3.

Microtubule associated proteins (MAPs) are essential cytoskeletal proteins in developing neurons. The present study was undertaken to analyze the expression of MAP2 and its isoforms (a,b,c) during the embryonal and early post-hatching development of chicken cochleovestibular ganglion (CVG) neurons. Moreover, we have investigated MAP2 expression in primary cultures of CVG neurons, and whether it is regulated by neurotrophin-3 (NT3). The expression of MAP2 immunoreactivity (IR) was studied using both Western blot and immunohistochemistry on tissue sections and primary cultures. In vivo MAP2c was expressed from incubation day 4 (E4) to E10, and MAP2b was found in all embryonal stages studied and at post-hatching day 10 (P10), whereas MAP2a was restricted to the post-hatching periods. The cellular localization of IR was in the neuronal perikarya and their peripheral processes (dendrites) but not in axons. Primary cultures matched the in vivo pattern of MAP2 expression, and IR was localized in neuronal cell bodies and the initial segment of the neuronal processes. Exogenous NT3 regulated the expression of MAP2 isoforms in a dose dependent manner. At the survival dose of 0.5 ng/ml NT3, the main MAP2 expression was MAP2c. Conversely, at the neuritogenic dose of 5 ng/ml NT3 increased MAP2b and MAP2a expression, but not MAP2c. The present results demonstrate that MAP2 isoforms are developmentally regulated, thus suggesting that each isoform is specifically involved in CVG neuron maturation. Furthermore, we provide evidence of MAP2 regulation in culture by the neurotrophic factor NT3.

Animals↗
PubMed1996

A clinical-parasitological monotherapy cure in the treatment of experimental infection by a highly virulent strain of Toxoplasma gondii.

Toxoplasmic encephalitis in patients with the acquired immunodeficiency syndrome (AIDS) is treated classically with pyrimethamine plus sulfadiazine. Unfortunately, up to 40% of these patients are unable to complete the course of therapy because of adverse reactions to sulfonamides. This study considers the possible usefulness of monotherapies in the treatment of acute toxoplasmosis, producing parasitological cures 2-3 months after the date of infection. With this therapy, the main adverse effects are suppressed. Groups of mice infected with the RH strain of Toxoplasma gondii were treated with pyrimethamine alone, sulfadiazine alone, and pyrimethamine plus sulfadiazine for 7 d. Treatment with pyrimethamine plus sulfadiazine produced clinical cures in 100% of the infected mice 1 month after infection. Treatment with pyrimethamine gave a 60% survival rate (clinical cure) at 1 month postinfection. Finally, treatment with sulfadiazine produced a 60% survival rate at 1 month postinfection. Although the antitoxoplasmic regimen with pyrimethamine plus sulfadiazine has proven to be effective in intensive treatment of toxoplasmic encephalitis, relapses occur in more than 80% of cases after cessation of antitoxoplasmic therapy, making secondary prophylaxis mandatory. In this study the efficacy of treatment was also evaluated in terms of parasitological cure. None of the three therapies showed parasitological cure after 1 month of treatment. When the intervals were extended to a 3-month observation, monotherapy with pyrimethamine and sulfadiazine alone produced a parasitological cure.

Animals↗
PubMed1996

Presynaptic receptors and the control of glutamate exocytosis.

When a typical glutamate-containing neurone fires, an action potential is propagated down the branching axon through more than a thousand varicosities. At each of these release sites the probability that a synaptic vesicle will be exocytosed into the synaptic cleft is individually controlled by means of presynaptic receptors: autoreceptors responding by positive or negative feedback to previously released transmitter, or heteroreceptors under the influence of other neurotransmitters or modulators. The simplest system in which to investigate presynaptic modulation is the isolated nerve terminal or synaptosome; studies with this preparation have revealed a complex interplay of signal-transduction pathways.

Animals↗
PubMed1996

Protein and microsatellite single locus variability in Salmo salar L. (Atlantic salmon).

We describe genetic variation at three microsatellite single loci and six allozyme loci of seven natural Atlantic salmon populations from Ireland and Spain. A comparison of genetic variability detected at both types of loci is performed. Also, the relative value of microsatellite single locus variability with regard to the identification of individual salmon populations is assessed. Microsatellite loci are shown to display higher levels of variation than allozyme loci. Mean number of alleles (6 +/- 1.53) and heterozygosity (0.46 +/- 0.04) at microsatellite loci are greater than those found for allozymes (1.85 +/- 0.05 and 0.21 +/- 0.03, respectively), and some microsatellite alleles appear to be specific for a location or geographical area. Allozyme and microsatellite variation show the same pattern of differentiation between populations with Irish and Spanish populations grouped into different clusters. However, greater values of genetic distance were found among microsatellite (D = 0.0747 +/- 0.011) rather than among allozyme loci (D = 0.0449 +/- 0.008). These results provide evidence that microsatellite-based analysis of genetic variation will be useful in the identification of individual populations of Atlantic salmon.

Alleles↗