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Biomedical subjects

M Valero

Publications and source records attributed to M Valero.

At least 19 recordsLinked to original sources
PubMed2006

Synergistic bactericidal effect of carvacrol, cinnamaldehyde or thymol and refrigeration to inhibit Bacillus cereus in carrot broth.

Possible use of three different essential oil components as natural food preservatives was studied by examining their influence in the kinetics of growth from activated spores of four Bacillus cereus strains in tyndallized carrot broth over the temperature range 5-16 degrees C. Selected low concentrations of carvacrol, cinnamaldehyde, or thymol showed a clear antibacterial activity against B. cereus in the vegetable substrate. The addition of 2 microl cinnamaldehyde or 20 mg thymol to 100 ml of broth in combination with refrigeration temperatures (<or= 8 degrees C) was able to inhibit the outgrowth from activated spores of the psychrotrophic strain INRA TZ415 for at least 60 days, but only cinnamaldehyde did it even at the mild abuse temperature of 12 degrees C. Five microliters of carvacrol per 100 ml of inoculated carrot broth, however, were unable to inhibit bacterial growth at 8 degrees C.

Acrolein↗
PubMed2006

[SPECT and PET in neurology].

Both single photon emission computed tomography (SPECT) and positron emission tomography (PET) are helpful in the practice of neurology. Ictal SPECT is useful to determine the origin of focal seizures in the pre-surgical evaluation. In some centers, it is used to predict the likelihood of massive cerebral swelling after stroke and of cerebral infarction after a subarachnoid hemorrhage. It has also been used to study dopaminergic function in parkinsonian syndromes and in the evaluation of dementia. Given its higher resolution and some other factors, PET is more useful in the evaluation of brain tumors, dementia and the parkinsonian syndromes. It is also useful in the presurgical evaluation of epilepsy.

Brain Diseases↗
PubMed2005

Effects of antimicrobial components of essential oils on growth of Bacillus cereus INRA L2104 in and the sensory qualities of carrot broth.

The possible use of antimicrobials from seven plant essential oils as food preservatives was studied by examining their effects on the growth kinetics of activated Bacillus cereus INRA L2104 spores inoculated into tyndallized carrot broth. The effects of various concentrations of borneol, carvacrol, cinnamaldehyde, eugenol, menthol, thymol, and vanillin were determined. Five microliters of cinnamaldehyde, 15 microl of carvacrol, or 30 mg of thymol per 100 ml of inoculated carrot broth completely inhibited bacterial growth for more than 60 days at 16 degrees C. Lower concentrations of the three antimicrobials prolonged the lag phase and reduced both the exponential growth rate and the final population densities of cultures. The study of the sensory characteristics of the supplemented broths suggested that low concentration of cinnamaldehyde enhanced the taste of carrot broth, and that it did not have any adverse effect on the taste and smell of carrot broth at concentrations less than 6 microl 100 ml(-1).

Anti-Bacterial Agents↗
PubMed2005

Modeling the influence of electron beam irradiation on the heat resistance of Bacillus cereus spores.

The effect of electron beam irradiation (EBI) on Bacillus cereus spore heat resistance was investigated. Irradiation with accelerated electrons had an important heat-sensitizing effect on distilled-water spore suspensions. After irradiation doses of 1.3, 3.1, or 5.7 kGy followed by heating at 90 degrees C, calculated D(90)-values for strains Escuela Politécnica Superior de Orihuela (EPSO)-41WR and EPSO-50UR were reduced more than 1.3, 2.4, and 4.6 times, respectively. Plots of calculated log D(T)-values versus irradiation doses (1.3, 3.1, and 5.7 kGy) yielded straight parallel lines for the 85-100 degrees C heating temperature range, which made it possible to develop an equation to predict the changes in heat sensitivity of B. cereus spores that occurred with changing irradiation dose. Radiation-induced heat-sensitivity was characterized by a z(EBI)-value which was determined as the irradiation dose that should be required to reduce the decimal reduction time (D(T)) by one log(10) cycle when log(10)D(T) was plotted against irradiation treatment. A model is proposed to describe the influence of a pre-irradiation treatment with electron beams followed by heating on the heat resistance of B. cereus spores. This study also suggests the potential use of EBI followed by heating for food preservation.

Bacillus cereus↗
PubMed2004

Mating system and gene flow in the red seaweed Gracilaria gracilis: effect of haploid-diploid life history and intertidal rocky shore landscape on fine-scale genetic structure.

The impact of haploid-diploidy and the intertidal landscape on a fine-scale genetic structure was explored in a red seaweed Gracilaria gracilis. The pattern of genetic structure was compared in haploid and diploid stages at a microgeographic scale (< 5 km): a total of 280 haploid and 296 diploid individuals located in six discrete, scattered rock pools were genotyped using seven microsatellite loci. Contrary to the theoretical expectation of predominantly endogamous mating systems in haploid-diploid organisms, G. gracilis showed a clearly allogamous mating system. Although within-population allele frequencies were similar between haploids and diploids, genetic differentiation among haploids was more than twice that of diploids, suggesting that there may be a lag between migration and (local) breeding due to the long generation times in G. gracilis. Weak, but significant, population differentiation was detected in both haploids and diploids and varied with landscape features, and not with geographic distance. Using an assignment test, we establish that effective migration rates varied according to height on the shore. In this intertidal species, biased spore dispersal may occur during the transport of spores and gametes at low tide when small streams flow from high- to lower-shore pools. The longevity of both haploid and diploid free-living stages and the long generation times typical of G. gracilis populations may promote the observed pattern of high genetic diversity within populations relative to that among populations.

Diploidy↗
PubMed2003

Antibacterial activity of 11 essential oils against Bacillus cereus in tyndallized carrot broth.

The antibacterial activity of 11 essential oils from aromatic plants against the strain INRA L2104 of the foodborne pathogen Bacillus cereus grown in carrot broth at 16 degrees C was studied. The quantity needed by the essential oils of nutmeg, mint, clove, oregano, cinnamon, sassafras, sage, thyme or rosemary to produce 14-1110% relative extension of the lag phase was determined. Total growth inhibition of bacterial spores was observed for some of the antimicrobial agents assayed. The addition of 5 microl cinnamon essential oil per 100 ml of broth in combination with refrigeration temperatures of <or=8 degrees C produced the conditions necessary to inhibit the growth of B. cereus for at least 60 days in a model, refrigerated minimally processed food product, made with carrots and tyndallized. This is especially important considering that the psychrotrophic enterotoxigenic strain of B. cereus INRA TZ415 was able to grow in this substrate at low temperatures in the absence of any essential oil. Furthermore, the study of the sensory characteristics of the final product suggests that the use of cinnamon essential oil can be considered as an alternative to "traditional food preservatives".

Bacillus cereus↗
PubMed2003

Influence of pH and temperature on growth of Bacillus cereus in vegetable substrates.

Bacillus cereus is a food-borne pathogen which most often contaminates foods of plant origin. Spores of psychrotrophic strains have the ability to germinate and grow at refrigeration temperatures in different vegetable substrates, such as carrot broth, zucchini broth, and cooked carrot purée. In some circumstances, factors such as pH, heat treatment, and storage temperature play a fundamental role in controlling the growth of these psychrotrophic strains and in extending the shelf life of refrigerated, minimally processed vegetable-based products in relation to pathogenic spore-forming bacteria. The combination of mild acidification (pH 5.0) and refrigeration (</=8 degrees C) inhibited B. cereus growth for at least 60 days in vegetable substrates similar to those mentioned above. This protection was maintained even when the temperature to which the food was exposed reached 12 degrees C. Psychrotrophic strains of B. cereus were inhibited in carrot broth by heating at 90 degrees C for 7.5 min, if the broth was refrigerated at a temperature of 8 degrees C or lower. If the vegetable product was exposed to temperatures of mild abuse (12 degrees C), it was necessary to implement a more drastic heat treatment (90 degrees C for 30 min).

Bacillus cereus↗
PubMed2002

Comparison of doses for pulmonary embolism detection with helical CT and pulmonary angiography.

The objective of this study was to compare the radiation exposure delivered by helical CT and pulmonary angiography (PA) for the detection of pulmonary embolism (PE), with an anthropomorphic phantom. A preliminary survey defined a representative standard procedure for helical CT and PA ( n=148) by choosing the exposure settings most frequently used. Then, radiation doses were measured with thermoluminescent dosimeters TLD 100 (Lif) introduced into the depth of an anthropomorphic phantom. Average doses were approximately five times smaller with helical CT than with PA (6.4+/-1.5 and 28+/-7.6 mGy, respectively). The most important doses were abreast the pulmonary apex for CT, and abreast the pulmonary arteries for PA. Compared with PA, helical CT dose distribution was relatively uniform (10-13 mGy). Finally, concerning abdomen and pelvis, doses were more important for PA than for CT scan (0.06-2.86 and 0.2-11.5 mGy, respectively). For the diagnostics of PE, radiation exposure is five times smaller with helical CT than with pulmonary angiography.

Angiography↗
PubMed2002

[Spirometry: quality in the respiratory medicine clinics of a public health care area].

BACKGROUND: Spirometry can be considered a routine way to evaluate patients with respiratory complaints, both inside and outside the hospital setting. OBJECTIVE: To assess the quality of spirometry in a public health care area with respect to two factors: the technicians' performance and the calibration of spirometers. MATERIAL AND METHOD: Four health care clinics were studied. Four technicians participated and the four spirometers were tested at different volumes (calibration syringes 1L and 3L) and different flows (explosive decompression). Eight patients with COPD participated in the study of inter-technician variability. RESULTS: Agreement among the technicians was very high: 0.98-0.99 for FEV1 and 0.91-0.98 for FVC. The mean results obtained by the technicians were: FEV1 = 2.15 0.03, range 2.20-2.14; FVC = 3.25 0.05, range 3.30-3.21 (ns). Volumetric readings from the spirometers were correct for the 1I calibration syringe, but 2 out of 4 spirometers lost linearity with the 3I calibration syringe. One spirometer gave readings out of range for all flow levels, and 2 out of 4 spirometers were out of range at low flows. CONCLUSIONS: 1. Results obtained by different technicians were not significantly different and there was high agreement among them, confirming that performance of spirometry was good. 2. The spirometers showed poor linearity at low flows.

Aged↗
PubMed2002

Polymerase chain reaction-single strand conformation polymorphism analyses of nuclear and chloroplast DNA provide evidence for recombination, multiple introductions and nascent speciation in the Caulerpa taxifolia complex.

Independent lines of evidence support an Australian origin for the Mediterranean populations of the tropical alga Caulerpa taxifolia. To complement previous biogeographical studies based on nuclear rDNA internal transcribed spacer (ITS), a new chloroplast marker was developed--the cp 16S rDNA intron-2. Sequence variability for both nuclear and chloroplast markers were assessed in 110 individuals using single strand conformation polymorphism. Comparison of intrapopulation genetic diversity between invasive Mediterranean and 'native' Australian populations revealed the occurrence of two divergent and widespread clades. The first clade grouped nontropical invasive populations with inshore-mainland populations from Australia, while the second clustered all offshore-island populations studied so far. Despite our finding of nine distinct nuclear and five distinct chloroplast profiles, a single nucleocytoplasmic combination was characteristic of the invasive populations and sexual reproduction was found to be very rare. C. taxifolia is clearly a complex of genetically and ecologically differentiated sibling species or subspecies.

Australia↗
PubMed2001

Phylogenetic analyses of Caulerpa taxifolia (Chlorophyta) and of its associated bacterial microflora provide clues to the origin of the Mediterranean introduction.

The accidental introduction of Caulerpa taxifolia into the Mediterranean is no longer under dispute. What has eluded researchers until now, is definitive evidence for the original, biogeographical source population. Here we present two independent lines of evidence that support an Australian origin for the Mediterranean populations of C. taxifolia. First, we reanalysed algal rDNA-internal transcribed spacer (rDNA-ITS) sequences, combining previously published sequences from different studies with 22 new sequences. The ITS sequence comparison showed that the Australian sample is the sister group of the Mediterranean-aquarium clade. Second, cloned bacterial 16S rDNA gene sequences were analysed from the associated microflora of C. taxifolia collected from Australia, Tahiti, the Philippines and the Mediterranean. Five bacterial lineages were identified, of which three were dominant. Alpha Proteobacteria were the most abundant and were found in all samples. In contrast, members of the beta Proteobacterial line and Cytophaga-Flexibacter-Bacteroides line (CFB) were mainly associated with Mediterranean and Australian samples. Frequency distributions of the five bacterial lineages were significantly different among biogeographical locations. Phylogenetic analyses of the 54 bacterial sequences derived from the four C. taxifolia individuals resulted in a well-resolved tree with high bootstrap support. The topologies of the beta Proteobacteria and CFB mirror the geographical sources of their algal hosts. Bacterial-algal associations provide an identification tool that may have wide application for the detection of marine invasions.

Base Sequence↗
PubMed2001

The spatial structure of sexual and cytonuclear polymorphism in the gynodioecious Beta vulgaris ssp. maritima: I/ at a local scale.

We have analyzed the spatial distribution of the sex phenotypes and of mitochondrial, chloroplast, and nuclear markers within two gynodioecious populations of Beta vulgaris ssp. maritima. Within both populations, sexual phenotype variation is controlled mainly by the cytoplasmic genotype, although in one study population a joint polymorphism of cytonuclear factors is clearly involved. In spite of contrasts in the ecology (mainly due to different habitats), a clear common feature in both populations is the highly patchy distribution of cytoplasmic haplotypes, contrasting with the wide distribution of nuclear diversity. This high contrast between cytoplasmic vs. nuclear spatial structure may have important consequences for the maintenance of gynodioecy. It provides opportunities for differential selection since nuclear restorer alleles are expected to be selected for in the presence of their specific cytoplasmic male sterile (CMS) type, but to be neutral (or selected against if there is a cost of restoration) in the absence of their CMS type. Selective processes in such a cytonuclear landscape may explain the polymorphism we observed at restorer loci for two CMS types.

Cell Nucleus↗
PubMed2000

A model for the evolution of high frequencies of males in an androdioecious plant based on a cross-compatibility advantage of males.

Lloyd's (1975) and Charlesworth & Charlesworth's (1978) phenotypic selection models for the maintenance of androdioecy predict that males (female-sterile individuals) must have an advantage in fertility (K) of at least two in order to invade a hermaphroditic population, and that their equilibrium frequency (x(eq)=(K - 2)/2(K - 1)) is always less than 0.5. In this paper, we develop a model in which male fertility is frequency-dependent, a situation not investigated in the previous models, to explore the conditions under which a high frequency of males (i.e. more than 50%) could be maintained at equilibrium. We demonstrate that a gametophytic self-incompatibility (GSI) locus linked to a nuclear sex determination locus can favour rare alleles through male function, by causing frequency-dependent selection. Thus, the spread of a female-sterility allele in a hermaphroditic population may be induced. In contrast with the previous models, our model can explain male frequencies greater than 50% in a functionally androdioecious species, as long as there is (i) dominance of female-sterility at the sex locus, and (ii) a few alleles at the self-incompatibility locus, even if the advantage in fertility of male phenotype is lower than two.

Biological Evolution↗
PubMed1999

Identification of random amplified polymorphic DNA (RAPD) markers highly linked to sex determination in the red alga Gracilaria gracilis.

The random amplified polymorphic DNA (RAPD) technique was employed in the haplo-diploid dioecious species Gracilaria gracilis to identify sex-linked PCR markers. Sixty-nine decamer oligonucleotide primers were tested on two bulks of DNA, one from five haploid males and the other from five haploid females. One of these primers (OPD13) generated a 430-bp fragment specific to males and a 620-bp fragment specific to females. The diploid individuals (tetrasporophytes) showed the co-occurrence of these two fragments. In order to verify the linkage between the sexual phenotypes and these markers, a progeny array of 59 haploid individuals (male and female) born on a diploid individual was analysed, in all of which the two markers produced by the OPD13 primer segregated perfectly with sex.

Base Sequence↗
PubMed1995

Hydrogen bonding in a non-steroidal anti-inflammatory drug--Naproxen.

Photophysical properties of a non-steroidal anti-inflammatory drug, Naproxen (6-methoxy alpha-methyl-2-naphthalene acetic acid sodium salt), were investigated in solvents of different polarity, hydrogen donor ability and also in cyclodextrins. The results indicate that in all cases the emitting state is the 1L(b) singlet. In alcoholic solvents, an intermolecular hydrogen bond is responsible for the observed photophysical behaviour of the probe whereas in non-protic solvents (polar and weakly polar) an intramolecular hydrogen bond type is postulated to rationalize the data found. In water, the non-radiative rate constant has a value similar to those found in aqueous solutions of alpha- and beta-cyclodextrins where the probe form complexes. The behaviour in water is explained by a water-structure enforced hydrophobic effect. The spectroscopic results are interpreted on the basis of a multiple-parameter model that considers specific solute-solvent interactions. These were also observed in the ground state and detected by Fourier transform infrared spectroscopy. Molecular mechanics (MM) and molecular orbital (AM1) calculations also support the existence of two conformations (rotamers) in Naproxen with non-equivalent intramolecular hydrogen bond-like formation.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1995

[The Royal Botanical Expedition to New Spain and the intention to start the Royal Botanical Garden in Havana].

The creation of a Botanical Garden in La Habana, at the beginning of the nineteenth century, was due to the efforts of the Real Sociedad Patriótica of La Havana and those of Martín de Sessé in 1795, member of the Botanical Expedition to Nueva España, who was commissioner for the recognition of natural productions and the organization of botanical studies and gardens at the colonies. The arrival of Sessé awakened the interest of some members of the Real Sociedad Patriótica with respect to the proposition made in 1793. A few years later, the Havana Garden was a reality.

Botany↗