Biomedical subjects

E Díaz

Publications and source records attributed to E Díaz.

At least 19 recordsLinked to original sources

PubMed2006

Energy balance and physical activity in obese children attending day-care centres.

OBJECTIVE: To evaluate energy balance and physical activity in obese preschool children attending day-care centres. DESIGN: Cross-sectional study. SUBJECTS: Twenty-four 3-5 years old obese children selected at random from four different day-care centres in Santiago City, Chile. Total energy expenditure (TEE) was measured by doubly labelled water and physical activity as recorded by TRITRAC R3D motion sensor. Energy intake was assessed by measuring food intake while at the centre, along with the recording of additional food intake in the home. RESULTS: Obese children had a 5.4% higher weighed energy intake than their energy requirements 2001. Energy intake during the week was 7716+/-1092 kJ/day and 7401+/-1023 kJ/day in boys and girls, respectively. Minimal activity was higher in the day-care centres (62%) compared to 52% during the weekend at home. Light activity was higher during the weekend at home than during the week (25 versus 20%), but moderate-intense activity was similar (3-5%). CONCLUSIONS: Reduction in dietary energy provided at the day-care centres helps to balance energy requirements during the week. Obese children had marked sedentary characteristics with regards to physical activity, although children are more active at home in weekends. This situation suggests that educators and parents need to improve children's physical activity levels and nutrition habits.

Child Day Care Centers↗

PubMed2005

Localisation of COX-2 protein is different in breast ductal carcinoma and adjacent non-tumour ductal epithelium.

INTRODUCTION: A number of findings suggest that cyclooxygenase-2 (COX-2) is overexpressed in breast tumours. However, there is a lack of consensus in the literature regarding the pattern of expression of this protein in invasive breast ductal carcinoma and in the adjacent non-tumour ductal epithelium. This study compares the expression of COX-2 mRNA and protein in breast ductal carcinoma relative to non-tumour breast tissue. MATERIAL AND METHODS: We analysed the expression of COX-2 mRNA by quantitative PCR, and COX-2 protein by immunohistochemistry in invasive ductal carcinoma as well as in non-tumour adjacent ductal epithelium from 34 breast biopsies diagnosed as being invasive ductal carcinoma. As control, we analysed expression of COX-2 protein by immunohistochemistry in surgically-resected benign breast lesions. RESULTS: Our results show that COX-2 mRNA and protein are overexpressed in non-tumour ductal epithelium compared with invasive ductal carcinoma. However, the pattern of the protein expression is different in tumour and non-tumour tissue: COX-2 protein is expressed predominantly in the membrane of the non-tumour ductal epithelium (including in benign breast lesions) while, in invasive ductal carcinoma cells, it is localised in the cytoplasm. CONCLUSIONS: The non-tumour ductal epithelium adjacent to invasive ductal carcinoma shows a higher COX-2 expression than does the invasive ductal carcinoma. However, the different localisation of the immunohistochemically-detected protein suggests a possible post-translational regulation of the protein.

Adult↗

PubMed2005

(1)H, (13)C NMR and X-ray crystallographic studies of highly polyhalogenated derivatives of costunolide lactone.

The costunolide lactone, a sesquiterpene compound isolated from Zaluzania triiloba species, reacted with several dihalocarbene sources produced by trihaloform-NaOH under successive phase transfer reactions yielding mono-, bis- and tris-dihalocyclopropane adducts. The structures, as well as the configurational assignments of the different derivatives, were established by (1)H and (13)C NMR spectroscopy and assisted by X-ray crystallographic and molecular modelling studies. The specific shielding of protons in the neighbourhood of different halogens on the cyclopropane moieties was correlated to the pseudocontact interactions.

Anthelmintics↗

PubMed2005

Dermatophytes growth curve and in vitro susceptibility test: a broth micro-titration method.

The introduction of systemic antifungal drugs which act upon different targets is the main issue of the in vivo antifungal resistance control. Different factors, such as growth curve phase, quality of the specimen, quantity of the inoculum, temperature, pH, culture medium composition, incubation duration and solvent, are believed important factors affecting minimum inhibitory concentration (MIC) value to most of the antifungal agents. We assayed an in vitro susceptibility test with 40 isolates of dermatophytes: Microsporum canis, Trichophyton rubrum, Trichophyton mentagrophytes and Epidermophyton floccosum against griseofulvin, fluconazole, itraconazole and terbinafine, using the guidelines of the M38-P document approved by the NCCLS. We determined the growth curves, to estimate the specific growth rate (mu max) and the generation time (G) of each dermatophyte, using dry weight and spectrophotometry methods. We demonstrate that, at 192 h, all fungi tested had a constant growth curve and we considered this as the optimal time for MIC determination. Terbinafine, griseofulvin and itraconazole possessed the highest antifungal activity against the four groups of dermatophytes studied. Fluconazole demonstrated no efficacy. Our MIC results differ from other authors and this difference is due to the timing of the MIC determination based on the growth curve of each fungi tested.

Antifungal Agents↗

PubMed2004

Anti-inflammatory activity of leaf extract and fractions of Bursera simaruba (L.) Sarg (Burseraceae).

Seeking for new medicinal compounds in plants used in traditional medicine, which grow in Venezuela, we investigated the anti-inflammatory activity of the leaf hexane extract (HE) and several fractions obtained from sp. Bursera simaruba (L.) Sarg. (Indio desnudo) using carrageenan-induced paw edema inflammation. Oral administration of leaf HE as well I (91-100) fraction, and compounds VIII 25-26 and VIII 29, inhibited the carrageenan-induced paw edema with different capacity and time course, over a period of 7h. The anti-inflammatory effect was comparable to that of the reference drug phenylbutazone (80 mg/kg, p.o.). Included in fraction I (91-100), Vitamin E was identified as one of its components and compound VIII 29 was identified as a methyl-beta-peltatin A. The comparison of the anti-inflammatory activity of VIII 29 fraction with the corresponding standard of methyl-beta-peltatin A, suggest that this compound could be one of the active principles involved in the anti-inflammatory activity of Bursera simaruba (L.) Sarg. leave. Our results contribute to the pharmacological support of the use of Bursera simaruba (L.) Sarg. as anti-inflammatory in the ethnomedicinal practice.

Administration, Oral↗

PubMed2003

1H,13C 2D NMR and X-ray studies of the products of the reaction between dibenzylidencyclohexanone and 6-amino-1,3-dimethyl uracil.

The reaction of the 6-amino-1,3-dimethyl uracil with the dibenzylidencyclohexanone (1), provided three adducts whose structures result from nucleophilic attack yielding the monoadduct 3 and two isomeric bisadducts (4 and 5) in moderate yields (50-60%). The structures obtained in this study were elucidated with 2D high resolution NMR experiments, variable temperature NMR and X-ray crystallographic studies. In compound 3, the tricyclic skeleton is essentially planar and the cyclohexane ring addopts an envelope conformation. The structures 4 and 5 correspond to two isomeric spiro compounds.

Crystallography, X-Ray↗

PubMed2003

Molecular ecology of anaerobic granular sludge grown at different conditions.

Qualitative and quantitative diversity of microorganisms present in anaerobic granular sludges fed with different substrates, as well as the structure of these granules have been studied using fluorescent 16S rRNA-targeted in situ hybridization and electron microscopy. The granules showed a multi-layered structure, in which both densely packed and loose micro-colonies, channels and holes could be observed. Only bacteria were found in the outer shell of the granules, while both archaea and bacteria were detected in the inner core. Although high cell density was found in the granules (more than 10(11) cells/gram, determined by DAPI-stain) only a low percentage of cells was able to hybridize with the rRNA-targeted probes. Significant quantitative and qualitative differences were observed in the composition of granules fed with different substrates (formate, acetate at high and low concentrations, propionate, sucrose, starch and peptone). Bacterial cells were mostly gram-positives. Active proteobacteria were scarce in the granules exposed to VFA. Syntrophobacteria became dominant in the propionate-grown biomass. Concerning methanogenic archaea, Methanosaeta was the predominant species using complex substrates or low acetate concentration fed granules, while Methanosarcina and members of Methanobacteriales were predominant in the granules grown at high concentration of acetate or formate, respectively. Other Methanomicrobiales and Methanococcales, have been detected in the anaerobic granular sludge in the conditions used in this work.

Bacteria, Anaerobic↗

PubMed2002

Associations between empirical antimicrobial therapy at the hospital and mortality in patients with severe community-acquired pneumonia.

INTRODUCTION: The aim of the study was to examine different antibiotic choices and their relation to outcomes. METHODS: We reviewed patients with severe community-acquired pneumonia (SCAP) from two multicenter studies. Empirical antimicrobial regimens were classified as: macrolides alone (group M); macrolides plus betalactams (group MB); macrolides plus betalactam/betalactamase inhibitor (group MBI); every regimen including aminoglycosides (group A); non-pseudomonal third-generation cephalosporins alone (group C); another betalactam alone (first- and second-generation cephalosporins, or betalactam/betalactamase inhibitor) (group B); fluoroquinolones (group F); and other regimens (group Misc). RESULTS: Initial distribution of regimens was: group MB: 261 patients; group A: 65 patients; group C: 31 patients; group B: 23 patients; group M: 18 patients; group MBI: 13 patients; group F: 11 patients; group Misc: 38 patients. The lowest overall mortality was associated with initial treatment with a macrolide plus other agent (or alone). No deaths were documented among the 13 patients receiving amoxicillin/clavulanate plus a macrolide. The excess mortality for initial treatment with group A was significantly higher (14.2%; CI 95% 27.3-1.1) than the overall mortality rate between patients receiving a macrolide plus other agents. No significant differences were documented when mortality was adjusted for intubated patients. CONCLUSION: Clinicians select the empirical antibiotic regimen after classifying patients according to likely pathogens and prognosis. The inclusion of a macrolide as part of the initial therapeutic regimen for SCAP appears to be as safe and effective as alternative options. Addition of a macrolide agent to a betalactam/betalactamase inhibitor or using a macrolide alone was a marker for less severe disease.

Adolescent↗

PubMed2002

Age differences in neurokinin A and substance P from the hypothalamus, pituitary, pineal gland, and striatum of the rat. Effect of exogenous melatonin.

Previous data showed that aging of the central nervous system (CNS) is associated with widespread changes in tachykinin gene expression. However, there are no data about the possible role of exogenous melatonin in modulating the tachykinergic system during aging. The aim of this work was to analyze the age-dependent changes on neurokinin A (NKA) and substance P (SP) levels in hypothalamus, pituitary, pineal gland and striatum and the role of exogenous melatonin on these changes. We studied female rats at three different ages: 5-month-old (cyclic), 15-month-old (preacyclic) and 25-month-old (acyclic). Hypothalamic tachykinin levels increase when female rats reached acyclicity, this increase was blunted in acyclic-melatonin-treated rats. However, melatonin treatment in young cyclic rats resulted in significantly increased values as compared to controls. Pituitary NKA concentrations did no show age-dependent changes in control rats, however, in both, preacyclic and acyclic-melatonin-treated rats significantly increased values of pituitary NKA were found compared to controls. In the pineal gland, a marked decrease of NKA levels was observed in acyclic-control rats. Melatonin treatment did not alter this decrease. In the striatum, NKA and SP concentrations were significantly reduced in preacyclic- and acyclic-control rats compared to young cyclic rats, melatonin had no effect on striatal tachykinins. Our results indicate that melatonin may regulate tachykinin stores during aging mainly on structures of the neuroendocrine-reproductive axis.

Aging↗

PubMed2002

2D 1H and 13C NMR evidences of the [2 + 2] autodimerization of 2-benzyl-5-benzylidene cyclopentanone yielding two different diphenyl, dispiro cyclobutane derivatives.

The ene-ene [2 + 2] cycloaddition of 2-benzyl-5-benzylidenecyclopentanone proceeds smoothly and spontaneously in benzene-d6 or deuteriochloroform solution to give two different diphenyl dispiro [4.1.4.1] dodecan-4,11-diones. Detailed 1H and 13C 2DNMR spectroscopy (COSY, HMQC, HMBC) were performed in order to prove the existence in solution of two cyclobutane derivatives, one a previously described photodimer obtained by the UV irradiation of crystals of 2-benzyl-5-benzylidenecyclopentanone.

Carbon Isotopes↗

PubMed2002

Production of culture filtrates of Sporothrix schenckii in diverse culture media.

Mycelial-form Sporothrix schenckii was studied to determine if growth in complex (Sabouraud-dextrose) or defined culture media (minimal medium, Gibco Medium 199 with and without Hepes buffer) with differing initial pH levels would affect expression of antigen components. Cultures were evaluated by continuous monitoring and serial sampling for various parameters. Great variation was seen in the protein and antigenic patterns induced by the different media. The expression of a 55 kDa component accompanied by significant acidification of the culture medium at the beginning of the stationary growth phase was notable in Sabouraud medium. In the chemically defined media, a 90 kDa component was expressed that reacted with sera from patients with sporotrichosis. The pH in these media showed little change during the different growth phases of the fungus. Among the media studied, minimal medium favored the expression of the greatest number of antigenic components. In all of the assays, the stationary growth phase appeared to be optimal for content of antigenic components. Cross reactions were not observed with any of the culture filtrates using sera from patients with other mycoses.

Culture Media↗

PubMed2001

Multicolour imaging of post-Golgi sorting and trafficking in live cells.

The biogenesis and maintenance of asymmetry is crucial to many cellular functions including absorption and secretion, signalling, development and morphogenesis. Here we have directly visualized the segregation and trafficking of apical (glycosyl phosphatidyl inositol-anchored) and basolateral (vesicular stomatitis virus glycoprotein) cargo in living cells using multicolour imaging of green fluorescent protein variants. Apical and basolateral cargo segregate progressively into large domains in Golgi/trans-Golgi network structures, exclude resident proteins, and exit in separate transport containers. These remain distinct and do not merge with endocytic structures suggesting that lateral segregation in the trans-Golgi network is the primary sorting event. Fusion with the plasma membrane was detected by total internal reflection microscopy and reveals differences between apical and basolateral carriers as well as new 'hot spots' for exocytosis.

Adenoviridae↗

PubMed2001

Effects of acetoacetate on in vitro development of bovine embryos in medium containing citrate and myo-inositol.

This study investigated bovine embryo development in vitro in the presence of acetoacetate in serum-free medium. In vitro-matured and fertilized oocytes from ovaries of slaughtered cows were cultured in synthetic oviduct fluid (SOF) containing citrate, myo-inositol, lactate and pyruvate. In the medium with acetoacetate this compound replaced both lactate and pyruvate as energy sources. Three experiments were carried out: (1) to test development in medium with acetoacetate and bovine serum albumin; (2) to analyse the effects of acetoacetate that were dependent upon citrate and myo-inositol; and (3) to determine the effects of acetoacetate in the presence of serum. Blastocyst development was recorded at day 8 and the number of cells of expanded blastocysts obtained were counted. Blastocysts development was reduced in medium with 1.8, 3.6 or 7.2 mM acetoacetate in comparison with the control with or without lactate and pyruvate. The detrimental effect of acetoacetate was independent of the presence of citrate and myo-inositol, but serum added to culture medium protected against this effect. Citrate and myo-inositol did not improve blastocyst formation. Morphological quality and cell number of blastocysts were similar between groups.

Acetoacetates↗

PubMed2001

Biodegradation of aromatic compounds by Escherichia coli.

Although Escherichia coli has long been recognized as the best-understood living organism, little was known about its abilities to use aromatic compounds as sole carbon and energy sources. This review gives an extensive overview of the current knowledge of the catabolism of aromatic compounds by E. coli. After giving a general overview of the aromatic compounds that E. coli strains encounter and mineralize in the different habitats that they colonize, we provide an up-to-date status report on the genes and proteins involved in the catabolism of such compounds, namely, several aromatic acids (phenylacetic acid, 3- and 4-hydroxyphenylacetic acid, phenylpropionic acid, 3-hydroxyphenylpropionic acid, and 3-hydroxycinnamic acid) and amines (phenylethylamine, tyramine, and dopamine). Other enzymatic activities acting on aromatic compounds in E. coli are also reviewed and evaluated. The review also reflects the present impact of genomic research and how the analysis of the whole E. coli genome reveals novel aromatic catabolic functions. Moreover, evolutionary considerations derived from sequence comparisons between the aromatic catabolic clusters of E. coli and homologous clusters from an increasing number of bacteria are also discussed. The recent progress in the understanding of the fundamentals that govern the degradation of aromatic compounds in E. coli makes this bacterium a very useful model system to decipher biochemical, genetic, evolutionary, and ecological aspects of the catabolism of such compounds. In the last part of the review, we discuss strategies and concepts to metabolically engineer E. coli to suit specific needs for biodegradation and biotransformation of aromatics and we provide several examples based on selected studies. Finally, conclusions derived from this review may serve as a lead for future research and applications.

Amines↗

PubMed2001

[Digestive refeeding in acute pancreatitis. When and how?].

BACKGROUND: Digestive refeeding in acute pancreatitis represent a difficult issue. It requires the resolution of intestinal ileus and carries a risk of reactivation. AIM: To evaluate criteria that may guide in early refeeding avoiding unnecessary prolonged fasting. PATIENTS AND METHODS: Thirty patients with acute pancreatitis were evaluated in a prospective trial. The severity of the pancreatitis was evaluated according to APACHE II score and Balthazar CT scan alterations. The criteria proposed to start early refeeding were absence of nausea and vomiting, decreased abdominal pain, presence of bowel sounds and lowering of serum amylase levels. Balthazar CT scan classification, was used to decide between oral or enteral refeeding. RESULTS: Eighty percent of patients had alterations in pancreatic density, necrosis or pancreatic or peripancreatic liquid collections in the CT scan (corresponding to Balthazar stages C, D, or E). Ten patients fullfilled the criteria for enteral refeeding at 8.1 +/- 3.5 days (range 3 to 15 days), and 21 patients fulfilled criteria fo enteral refeeding at 8.7 +/- 4.5 (range 4-19). No patient had a reactivation of his pancreatitis. CONCLUSIONS: Digestive refeeding can be done safely by using the criteria proposed in this study. Pancreatic necrosis or peripancreatic fluid collections do not contraindicate refeeding. Oral feeding may be employed (as the first option) in selected patients, without increasing the risk of complication, regardless of CT scan alterations of the pancreas.

Acute Disease↗

PubMed2000

Prenatal melatonin exposure affects luteinizing hormone and hypothalamic and striatal neuropeptide Y in the male rat offspring.

The present study examines the influence of prenatal melatonin on the hypothalamic and striatal neuropeptide Y (NPY) concentrations as well as on luteinizing hormone (LH) levels. Male rat offspring of control and melatonin treated mother rats were studied at different ages of the sexual development: infantile, prepubertal, pubertal and adult ages. Hypothalamic NPY levels were much higher during the juvenile than throughout the infantile period. After prenatal melatonin treatment significantly higher values since day 15 up to 35, also at 60 days of age were found, as compared with controls. Striatal NPY levels were lower than in hypothalamus. Again, NPY in the striatum from offspring of melatonin treated mother rats showed significantly higher values than the respective controls at most of the ages studied. However, prenatal melatonin exerted an inhibitory influence upon LH secretion pattern, since decreased concentrations up to 25 days of age and delayed peak values at pubertal age were observed. The present study also suggest that the effect of NPY upon LH secretion is related to sexual development, since NPY exerted opposite effect in infantile than in pubertal period and melatonin administration during intrauterine life prevented this effect.

Aging↗

PubMed2000

Transcriptional regulation of the divergent paa catabolic operons for phenylacetic acid degradation in Escherichia coli.

The expression of the divergently transcribed paaZ and paaABCDEFGHIJK catabolic operons, which are responsible for phenylacetic acid (PA) degradation in Escherichia coli, is driven by the Pz and Pa promoters, respectively. To study the transcriptional regulation of the inducible paa catabolic genes, genetic and biochemical approaches were used. Gel retardation assays showing that the PaaX regulator binds specifically to the Pa and Pz promoters were complemented with in vivo experiments that indicated a PaaX-mediated repression effect on the expression of Pa-lacZ and Pz-lacZ reporter fusions. The region within the Pa and Pz promoters that is protected by the PaaX repressor in DNase I footprinting assays contains a conserved 15-base pair imperfect palindromic sequence motif that was shown, through mutational analysis, to be indispensable for PaaX binding and repression. PA-coenzyme A (PA-CoA), but not PA, specifically inhibited binding of PaaX to the target sequences, thus confirming the first intermediate of the pathway as the true inducer and PaaX as the only bacterial regulatory protein described so far that responds to an aryl-CoA compound. Superimposed in the specific PaaX-mediated regulation is transcriptional activation by the cAMP receptor protein and the integration host factor protein. These global regulators may adjust the transcriptional output from Pa and Pz promoters to the overall growth status of the cell.

Acetyl Coenzyme A↗

PubMed2000

Antifungal monoterpene production in elicited cell suspension cultures of Piqueria trinervia.

Cell suspension cultures of the traditional medicinal plant Piqueria trinervia Cav., which synthesizes monoterpene piquerol A, were established. A defense response was induced in the cultures when eight homogenized fungi isolated from wild populations of P. trinervia were added. Piquerol A was not produced in the elicited system, while four other substances were synthesized de novo. They were excreted into the medium and inhibited in vitro fungal growth. The most abundant substance produced in this system was a new monoterpene: 2-methylene-7,7-dimethylbicyclo (3,3,1) heptane-4,6-diol. Monoterpenes in the cell suspension culture reported here were produced via two metabolic channels: the first acted constitutively and expressed in liquid and solid cultures, the second is inducible in response to several pathogens and elicitor substances.

Antifungal Agents↗