Biomedical subjects

I González

Publications and source records attributed to I González.

At least 19 recordsLinked to original sources

PubMed2006

Ultrasonic characterization of granites obtained from industrial quarries of Extremadura (Spain).

The industry of ornamental rocks, such as granites, represents one of the most important industrial activities in the region of Extremadura, SW Spain. A detailed knowledge of the intrinsic properties of this natural stone and its environmental evolution is a required goal in order to fully characterize its quality. In this work, two independent NDT acoustic techniques have been used to measure the acoustic velocity of longitudinal waves in different prismatic granitic-samples of industrial quarries. A low-frequency transceiver set-up, based on a high-voltage BPV Steinkamp instrument and two 50 kHz probes, has been used to measure pulse travel times by ultrasonic through-transmission testing. In complementary fashion, an Erudite MK3 test equipment with an electromagnetic vibrator and two piezoelectric sensors has also been employed to measure ultrasonic velocity by means of a resonance-based method, using the same types of granite varieties. In addition, a comprehensive set of physical/mechanical properties have also been analyzed, according to Spanish regulations in force, by means of alternative methods including destructive techniques such as strength, porosity, absorption, etc. A large number of samples, representing the most important varieties of granites from quarries of Extremadura, have been analyzed using the above-mentioned procedures. Some results obtained by destructive techniques have been correlated with those found using ultrasonic techniques. Our experimental setting allowed a complementary characterization of granite samples and a thorough validation of the different techniques employed, thus providing the industry of ornamental rocks with a non-destructive tool that will facilitate a more detailed insight on the properties of the rocks under study.

Journal Article↗

PubMed2006

Application of high intensity air-borne ultrasound for debubbling liquid coating layers.

In the coating processes, the formation of bubbles and microbubbles is relatively frequent inside the coating layer. Such bubbles, which are formed as a consequence of air retention, are difficult to remove and specifically in high-speed (quick-drying) industrial application where they cause permanent imperfections in the homogeneity of the layer. High-intensity air-borne ultrasound may represent a clean means to improve homogenization by quickly breaking the bubbles just when they are formed inside the coating film. This paper deals with the direct application of air-borne high-intensity ultrasonic radiation at a frequency of about 21 kHz over coating layers just immediately they have been deposited over wood substrates. Such novel process has been implemented and experimentally studied at laboratory and semi-industrial stages.

Coated Materials, Biocompatible↗

PubMed2006

The present environmental scenario of the Nador Lagoon (Morocco).

In this paper, we present a multivariate approach (waters, sediments, microfauna) concerning the environmental state of the Nador Lagoon (NE Morocco). The normal water quality parameters (salinity, pH, nutrients) of the dominant marine flows are altered by local fecal water effluents, urban discharges, sewages derived from a water treatment station, and residues originated in a slaughterhouse. The geochemical analyses carried out in surficial sediment samples show very high concentrations of all metals studied near an old iron mine and moderate contents between Nador and its treatment station. Ostracods are good bioindicators of these environmental impacts, with the presence of a highly brackish assemblage in the quieter, more confined areas or the appearance of opportunistic species under hypoxic conditions. In addition, these microcrustaceans are absent in polluted bottom sediments or areas with high hydrodynamic gradients, whereas they decrease in both density and diversity if the subaerial exposure increases.

Abattoirs↗

PubMed2006

Lateral root initiation in Arabidopsis: developmental window, spatial patterning, density and predictability.

BACKGROUND AND AIMS: The basic regulatory mechanisms that control lateral root (LR) initiation are still poorly understood. An attempt is made to characterize the pattern and timing of LR initiation, to define a developmental window in which LR initiation takes place and to address the question of whether LR initiation is predictable. METHODS: The spatial patterning of LRs and LR primordia (LRPs) on cleared root preparations were characterized. New measures of LR and LRP densities (number of LRs and/or LRPs divided by the length of the root portions where they are present) were introduced and illustrate the shortcomings of the more customarily used measure through a comparative analysis of the mutant aux1-7. The enhancer trap line J0121 was used to monitor LR initiation in time-lapse experiments and a plasmolysis-based method was developed to determine the number of pericycle cells between successive LRPs. KEY RESULTS: LRP initiation occurred strictly acropetally and no de novo initiation events were found between already developed LRs or LRPs. However, LRPs did not become LRs in a similar pattern. The longitudinal spacing of lateral organs was variable and the distance between lateral organs was proportional to the number of cells and the time between initiations of successive LRPs. There was a strong tendency towards alternation in LR initiation between the two pericycle cell files adjacent to the protoxylem poles. LR density increased with time due to the emergence of slowly developing LRPs and appears to be unique for individual Arabidopsis accessions. CONCLUSIONS: In Arabidopsis there is a narrow developmental window for LR initiation, and no specific cell-count or distance-measuring mechanisms have been found that determine the site of successive initiation events. Nevertheless, the branching density and lateral organ density (density of LRs and LRPs) are accession-specific, and based on the latter density the average distance between successive LRs can be predicted.

Arabidopsis↗

PubMed2006

First 100 liver transplants at the medico-surgical research center (CIMEQ).

In July 1999 we began a liver transplant program that to October 2005 has included 100 liver transplants in 92 patients, eight retransplants, and two combined liver and kidney grafts. Twelve transplants were in pediatric patients, who showed a 92% survival rate in the first year. Fifty-four percent of the patients were male and 46% female. The most frequent etiologies of cirrhosis were 27% hepatitis virus C, 18% alcoholic, 13% cryptogenic, and 11% autoimmune. In 95% of the patients, we preserved the retrohepatic vena cava. The bile duct was reconstructed with a Kehr tube in 46% of patients with 31% using end-to-end suture with a tutor and 15% an end-to-end suture without a tutor. A hepaticojejunostomy was performed in 8%. The immunosuppression included cyclosporine (Neoral) or Prograf combined with mycophenolate mofetil or mycophenolate sodium and steroids. The most frequent biliary complications were local anastomosis leaks (6%) and stenosis (10%). The overall 1-year survival rate was 72%.

Cuba↗

PubMed2006

Immediate hypersensitivity to corticosteroids.

INTRODUCTION: In comparison with the extremely frequent use of corticosteroids in different diseases, immediate allergic reactions remain uncommon. In addition to the steroid molecule, the causative agent of these reactions can be an excipient. MATERIAL AND METHODS: We report seven cases of immediate reactions induced by different preparations of corticosteroids. Skin tests with the suspected steroid and excipients were carried out. In patients with negative skin tests, oral or parenteral challenges were performed with the drug and the excipients involved. Challenge tests with at least two other corticosteroids belonging to another or even the same group of the Coopman classification were carried out. RESULTS: Of the 7 patients, six had positive skin tests with the suspected preparation of corticoid: three cases with methylprednisolone acetate, two cases with carboxymethylcellulose and one case with the complete triamcinolone preparation. Only in one case did we have to challenge with the suspected steroid preparation to confirm the diagnosis. All challenge tests with other corticosteroids belonging to another or to the same group of the Coopman classification were negative. CONCLUSIONS: The reactions were caused by the steroid molecule (Triamcinolone or methylprednisolone succinate) in four patients, by an excipient (carboxymethylcellulose) in another two patients and we could not identify the sensitized molecule in one patient. We did not demonstrate cross-reactivity between different corticosteroids.

Adrenal Cortex Hormones↗

PubMed2005

Scleroderma with type III glomerulonephritis and MPO-ANCA antibodies in the serum.

Scleroderma is an autoimmune disease characterized by early inflammatory infiltrates followed by fibrosis in the skin and internal organs. CREST is a relatively benign cutaneous variant of scleroderma that features calcinosis, Raynaud's phenomenon, oesophageal dysfunction, sclerodactyly and telangiectases. Glomerulonephritis is a rare association of CREST. We are reporting a patient with CREST who developed glomerulonephritis and had anticentromere and antineutrophil cytoplasmic autoantibodies (ANCA) in her serum.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed2005

Application of polymerase chain reaction to detect adulteration of sheep's milk with goats' milk.

The polymerase chain reaction has been applied for the specific detection of goats' milk in sheep's milk using primers targeting the mitochondrial 12S ribosomal RNA gene. The use of goat-specific primers yielded a 122-bp fragment from goats' milk DNA, whereas no amplification signal was obtained in sheep's, cows', and water buffaloes' milk DNA. Polymerase chain reaction analysis of raw and heat-treated milk binary mixtures of sheep/goat enabled the specific detection of goats' milk with a sensitivity threshold of 0.1%. This study demonstrates the usefulness of the proposed polymerase chain reaction assay for authentication of milk products in routine analysis.

Animals↗

PubMed2005

Immediate hypersensitivity to quinolones: moxifloxacin cross-reactivity.

INTRODUCTION: Immediate hypersensitivity reactions to quinolones are rare. Moxifloxacin is an quinolone chemically different from other fluoroquinolones. We report 6 patients diagnosed with hypersensitivity to different fluoroquinolones in whom the response to moxifloxacin and cross-reactivity with other quinolones was studied. MATERIAL-METHODS: An allergenic study was made by prick and intradermal test with different fluoroquinolones, in all the patients. Single blind oral challenge tests were performed with moxifloxacin in all the patients, with ciprofloxacin in five patients, with levofloxacin in three patients and with ofloxacin in one patient. RESULTS: The skin test performed with moxifloxacin was positive in five patients, and the oral challenge test was positive in all six patients. All the patients had at least one positive skin test with some of the other fluoroquinolones. CONCLUSION: The skin test with different quinolones seems to be sensitive at showing group hypersensitivity, but not at predicting specific tolerance of each drug. We found a high degree of cross-reactivity among fluoroquinolones, so we currently recommend to avoid the group. We did not find that moxifloxacin differed from other fluoroquinolones so we cannot recommend it as a valid therapeutic alternative in patients sensitized to other quinolones.

Adult↗

PubMed2005

Occupational asthma caused by white mushroom.

The commercial growing of white mushroom (Agaricus bisporus) is a frequent activity in certain Spain regions as La Rioja. We report two cases of white mushroom workers suffering from asthma caused by hypersensitivity to basidiocarp and spores of white mushroom.

Adult↗

PubMed2004

Tridimensional animated brain mapping from conventional paper-ink EEG recordings.

One of the most powerful functional evaluations of the electrical activity of the brain is the EEG imaging, but wide clinical use is limited by its costs. It is also of clinical, academic and scientific interest to obtain brain electrical maps from old paper/ink, patient recordings. The aim of the present study was the development of a computer system designed to obtain bidimensional and tridimensional maps, continuous movie map display and mosaic presentation from conventional paper/ink EEG recordings. The wave amplitude was manually measured with a translucent template from conventional 8- to 16-channel EEG paper recordings using 10-20 monopolar montage for one or both hemispheres. The computer system allows the selection of the number and location of electrodes, input of amplitude values, and the map display mode. The electrical brain field was generated from amplitude measurements by a spherical splines interpolation algorithm on a conventional Pentium-based computer. The interpolated surface was represented on a semi-sphere modeled skull. The EEG maps displayed with pseudo-color or gray scales can be rotated, zoomed in or zoomed out and/or printed for clinical reports. Movie animation or mosaic display of space-temporal EEG voltage changes were generated by processing sequential amplitude measurements. This system represents a cost-effective method for EEG mapping from conventional paper/Ink EEG equipments.

Brain Mapping↗

PubMed2004

Electrochemical treatments for selective growth of different calcium carbonate allotropic forms on carbon steel.

Different allogropic forms of calcium carbonate scales (calcite and aragonite) were electrochemically deposited on carbon steel surfaces, using different electrochemical techniques: cyclic voltammetry or potentiostatic pulses. To simulate conditions of Mexican refinery cooling systems, this study was performed in the presence of known concentrations of other salts at pH 7.8 and 40 degrees C with low and high calcium carbonate concentrations. Reduction reactions for dissolved oxygen and water occurring in such systems modified the pH at the substrate-solution interface to promote scaling of the calcium carbonate present. A systematic scanning electron microscopy and X-ray diffraction analysis of the carbon steel surface showed that the formation of calcite and aragonite depended on the initial state of substrate surface (clean or damaged) and on the concentration of calcium carbonate present in the system.

Calcium Carbonate↗

PubMed2004

Rapid detection of cows' milk in sheeps' and goats' milk by a species-specific polymerase chain reaction technique.

A polymerase chain reaction (PCR) assay was developed for the specific identification of cows' milk in sheep's and goats' milk by using primers targeting the mitochondrial 12S rRNA gene. The use of a forward primer complementary to a conserved DNA sequence, along with a reverse primer specific for cow, yielded a 223-bp fragment from cows' milk DNA, whereas no amplification signal was obtained in sheep's and goats' milk DNA. The technique was applied to raw, pasteurized, and sterilized milk binary mixtures of cow-sheep and cow-goat, enabling the specific detection of cows' milk with a good sensitivity threshold (0.1%). The proposed PCR assay represents a rapid and straightforward method applicable to the authentication of milk and other dairy products in routine analysis.

Animals↗

PubMed2003

Intestinal coccidia in Cuban pediatric patients with diarrhea.

From May to August 1999, we evaluated 401 patients from a pediatric hospital of Havana City. One group was composed of 113 patients with diarrhea admitted to the Gastroenterology ward and a second consisted of 288 patients without diarrhea, admitted for other reasons, and hospitalized within the same time period. Three stool samples were collected from each child and were examined using three parasitological techniques. When we compared the frequency of parasite species between both groups, we found Cryptosporidium spp. and Cyclospora cayetanensis, only in the group of children with diarrhea (P < 0.01). However, no significant differences were found in the occurrence of the other intestinal parasites (P > 0.05). In addition, in those children infected with Cryptosporidium, the diarrhea had a more prolonged duration (P < 0.01), while those infected with Cyclospora, the abdominal cramps or pain, and acute diarrhea were more frequently detected (P < 0.01). Our results showed that emerging intestinal coccidia are pathogens strongly associated in this group of children with diarrhea.

Animals↗

PubMed2003

Effects of beta-amyloid protein on serotoninergic, noradrenergic, and cholinergic markers in neurons of the pontomesencephalic tegmentum in the rat.

The effects on serotoninergic, noradrenergic and cholinergic markers on neurons of the pontomesencephalic tegmentum nuclei were studied in rats following local administration of fibrillar beta-amyloid peptide (Abeta1-40) into the left retrosplenial cortex. Focal deposition of Abeta in the retrosplenial cortex resulted in a loss of serotoninergic neurons in the dorsal and median raphe nuclei. The dorsal raphe nucleus showed a statistically significant reduction of 31.7% in the number of serotoninergic neurons and a decrease (up to 17.38%) in neuronal density in comparison with the same parameters in uninjected controls. A statistically significant reduction of 50.3%, together with a significant decrease of 53.94% in the density of serotoninergic neurons, was also observed in the median raphe nucleus as compared with control animals. Furthermore, a significant reduction of 35.07% in the number of noradrenergic neurons as well as a statistically significant decrease of 56.55% in the density of dopamine-beta-hydroxylase-immunoreactive neurons were also found in the locus coeruleus as compared with the corresponding hemisphere in uninjected controls. By contrast, a reduction of 24.37% in the number of choline acetyltransferase-positive neurons and a slight decrease (up to 22.28%) in the density of cholinergic neurons, which were not statistically significant, was observed in the laterodorsal tegmental nucleus in comparison with the same parameters in control animals. These results show that three different neurochemically defined populations of neurons in the pontomesencephalic tegmentum are affected by the neurotoxicity of Abeta in vivo and that Abeta might indirectly affect serotoninergic, noradrenergic and cholinergic innervation in the retrosplenial cortex.

Acetylcholine↗

PubMed2003

Patterns of antimicrobial activities from soil actinomycetes isolated under different conditions of pH and salinity.

AIMS: To evaluate the patterns of the production of antimicrobial compounds by diverse collection of actinomycetes isolated from different geographies under alternative conditions of pH and salinity in the media. METHODS AND RESULTS: Actinomycetes were grouped based on their method of isolation and their phenotype diversity was determined by total fatty acid analysis. A total of 335 representative isolates, including 235 Streptomyces species and 100 actinomycetes from other taxa, were screened for the production of antimicrobial activities against a panel of bacteria, filamentous fungi and yeasts, including some of clinical relevance. Production of antimicrobial activities was detected in 230 strains. In the case of the genus Streptomyces, 181 antimicrobial activities (77% of the tested isolates) were recorded. The activities observed among the other actinomycetes taxa were lower (49% of the tested isolates). CONCLUSIONS: The results of this study support the idea that species of actinomycetes isolated in alternative selective conditions of pH and salinity present a significant capacity to produce compounds with antibacterial or antifungal activity. The best group of isolates in terms of production of active secondary metabolites was the one isolated in saline conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: The results demonstrate that these actinomycetes strains isolated in alternative selective conditions of pH and salinity and collected from diverse geographical locations present a significant capacity to produce compounds with antibacterial or antifungal activity.

Actinobacteria↗

PubMed2003

Hereditary angioedema and pneumomediastinum.

Gastrointestinal and respiratory involvement is common in hereditary angioedema, laryngeal edema being the main cause of mortality in these patients. We report the case of an 18 year-old woman with a history of hereditary angioedema, who presented an episode of coughing and vomiting the night before, and who was diagnosed with pneumomediastinum as a complication of an episode of angioedema. We review the causes and pathogenesis of the mediastinic emphysema.

Adolescent↗

PubMed2002

Relationship between molecular structure and electron targets in the electroreduction of benzocarbazolediones and anilinenaphthoquinones. Experimental and theoretical study.

We report the synthesis and voltamperometric reduction of 5H-benzo[b]carbazole-6,11-dione (BCD) and its 2-R-substituted derivatives (R = -OMe, -Me, -COMe, -CF(3)). The electrochemical behavior of BCDs was compared to that of the 2-[(R-phenyl)amine]-1,4-naphthalenediones (PANs) previously studied. Like PANs, BCDs exhibit two reduction waves in acetonitrile. The first reduction step for the BCDs represents formation of the radical anion, and the half-wave potential (E(1/2)) values for this step are less negative than for that of the PANs. The second reduction wave, corresponding to the formation of dianion hydroquinone, has E(1/2) values that shift to more negative potentials. A good linear Hammett-Zuman (E(1/2) vs sigma(p)) relationship, similar to that for the PAN series, was also obtained for the BCDs. However, unlike the PANs, in the BCDs, the first reduction wave was more susceptible to the effect of the substituent groups than was the second wave, suggesting that the ordering of the two successive one-electron reductions in BCDs is opposite that in PANs. This is explained by the fact that the electron delocalizations in the two systems are different; in the case of BCDs there is an extra aromatic indole ring, which resists loss of its aromatic character. The electronic structures of BCD compounds were, therefore, investigated within the framework of the density functional theory, using the B3LYP hybrid functional with a double zeta split valence basis set. Our theoretical calculations show that the O(1).H-N hydrogen bond, analogous to that previously described for the PAN series, is not observed in the BCDs. Laplacians of the critical points (nabla(2)rho) and the natural charges for the C-O bonds indicate that the first reduction wave for the BCDs corresponds to the C(4)-O(2) carbonyl, while in the PAN series the first one-electron transfer occurred at the C(1)-O(1) carbonyl. Natural bond orbital analysis showed that, in all the BCDs, the lowest unoccupied molecular orbital (LUMO) is located at C(4), whereas for the PANs, the LUMO is found at C(1). The good correlation between the LUMO energy values and the E(1/2) potentials (wave I) established that the first one-electron addition takes place at the LUMO. Analysis of the molecular geometry confirmed that, in both series of compounds, the effect of the substituent groups is mainly on the C(4)-O(2) carbonyl. These results explain the fact that reduction of the C(4)-O(2) carbonyl (voltammetric wave II in the PANs and voltammetric wave I in the BCDs) is more susceptible to the effect of the substituent groups than is reduction of the C(1)-O(1) carbonyl (wave I in the PANs and wave II in the BCDs).

Carbazoles↗