Biomedical subjects

A Domínguez

Publications and source records attributed to A Domínguez.

At least 55 records · Page 3Linked to original sources

PubMed2002

The epidemiology of invasive Streptococcus pneumoniae disease in Catalonia (Spain). A hospital-based study.

The aim of this study was to investigate the incidence of invasive pneumococcal disease (IPD) in Catalonia. A hospital-based incidence study of the period 1997-1999 was carried out by reviewing the isolations of Streptococcus pneumoniae obtained from normally sterile sites reported by the hospitals that voluntarily participate in the Microbiological Reporting System of Catalonia (MRSC), and those obtained by active retrospective surveillance of cases recorded by microbiology laboratories of the remaining hospitals. Cases of pneumonia were included only if the blood culture was positive. The age, sex and clinical presentation of each patient were recorded. The global incidence of hospital-based IPD was 10.5 per 100,000 persons-year, and was much higher in subjects <2 years of age (59.6) and in those aged > or = 65 years (27.9). In subjects > or = 65 years, bacteremic pneumococcal pneumonias were more frequent in the months from December to March than they were in children <2 years of age (P<0.0001). The global incidence of IPD (10.5 per 100,000 persons-year) is high in Catalonia, greater than that of meningococcal or Haemophilus influenzae invasive disease. In children <2 years, the incidence is nearly six times higher (59.6 per 100,000 persons-year) with pneumonias (rate of 26.2 per 100,000 persons-year) and non-focal bacteremias (rate of 22.1 per 100,000 persons-year) being especially frequent.

Adolescent↗

PubMed2002

Regeneration of transgenic citrus plants under non selective conditions results in high-frequency recovery of plants with silenced transgenes.

Insertion of foreign DNA into plant genomes frequently results in the recovery of transgenic plants with silenced transgenes. To investigate to what extent regeneration under selective conditions limits the recovery of transgenic plants showing gene silencing in woody species, Mexican lime [ Citrus aurantifolia (Christm.) Swing.] plants were transformed with the p25 coat protein gene of Citrus tristeza virus (CTV) with or without selection for nptII and uidA. Strikingly, more than 30% of the transgenic limes regenerated under non-selective conditions had silenced transgenes, and in all cases silencing affected all the three transgenes incorporated. These results indicate that the frequency of transgene silencing may be greatly underestimated when the rate of silencing is estimated from the number of regenerants obtained under selective conditions. To our knowledge, this is the first report in which the frequency of gene silencing after transformation has been quantified. When the integration pattern of T-DNA was analyzed in silenced and non-silenced lines, it was observed that inverted repeats as well as direct repeats and even single integrations were able to trigger gene silencing. Gene silencing has often been associated with the insertion of DNA sequences as inverted repeats. Interestingly, here, direct repeats and single-copy insertions were found in both silenced and non-silenced lines, suggesting that the presence of inverted-repeat T-DNAs and the subsequent formation of dsRNAs triggering gene silencing cannot account for all silencing events.

Citrus↗

PubMed2002

Production of manganese-dependent peroxidase in a new solid-state bioreactor by Phanerochaete chrysosporium grown on wood shavings. Application to the decolorization of synthetic dyes.

The production of manganese-dependent peroxidase (MnP) by Phanerochaete chrysosporium in a new solid-state bioreactor, the immersion bioreactor, operating with lignocellulosic waste, such as wood shavings, was investigated. Maximum MnP and lignin peroxidase (LiP) activity of 13.4 and 8.48 mukat/L were obtained, respectively. The in vitro decolorization of several synthetic dyes by the extracellular liquid produced in the above-mentioned bioreactor (containing mainly MnP) was carried out and its degrading ability was assessed. The highest decolorization was reached with Indigo Carmine (98%) followed by Bromophenol Blue (56%) and Methyl Orange (36%), whereas Gentian Violet was hardly decolorized (6%).

Biodegradation, Environmental↗

PubMed2002

Impact of highly active antiretroviral therapy on fever of unknown origin in HIV-infected patients.

In order to assess the impact of highly active antiretroviral therapy (HAART) on the frequency and etiology of fever of unknown origin in HIV-infected patients, a retrospective study was performed on cases of fever of unknown origin observed from January 1997 to December 1999 in seven hospitals in five cities in Andalusia, Spain. During the period specified, a total of 4,858 HIV-infected patients receiving HAART and 2,787 HIV-infected individuals not receiving HAART were studied. The frequency of fever of unknown origin was 0.6% in patients receiving HAART and 3% in non-HAART patients (P=0.001). Human immunodeficiency virus infection was the only cause of fever found more frequently in the non-HAART patient group (P=0.07). The study findings suggest that the use of HAART has reduced the frequency of fever of unknown origin in HIV-infected patients, but the etiology of the condition remains mostly unchanged.

Adult↗

PubMed2002

Photocatalytic degradation of dyes in aqueous solution operating in a fluidised bed reactor.

This work reports a preliminary design of a new photochemical reactor and its application to photochemical degradation of two dyes, Crystal Violet and Azure B, operating in both batch and continuous processes. A novel kind of photocatalyst, consisting of ZnO immobilised in alginate gel beads, which is able to photodegrade organic dyes effectively, has been employed in the present study. When this photocatalyst, at a concentration of 1 g of ZnO per litre of alginate gel at 3%, was employed in batch process, almost total decolourisation of Crystal Violet in reaction times lower than 120 min was observed. Operating in continuous process at different residence times, it was possible to achieve a total decolourisation of both Crystal Violet and Azure B. Moreover, the total organic carbon content (TOC) was reduced to 90% in the former and to 52% in the latter. These results indicated that the photoreactor developed in the present work was able to degrade effectively dyes of different structures, revealing the non-specificity of the system.

Alginates↗

PubMed2002

[Tuberculin test responses of tuberculosis patients].

OBJECTIVE: To determine the response of tuberculosis patients to tuberculin skin tests. METHOD: The results of skin tests used for initial assessment of tuberculosis patients in Catalonia were reviewed (Multicenter Tuberculosis Research Project). Negative skin tests were those with indurations < 5 mm; positive tests were those with indurations measuring > or = 5 mm. Individuals were classed as having or not having risk factors for developing tuberculosis and those without risk factors were classified by age, location and extension of tuberculosis. RESULTS: Negative skin tests were seen in 1,566 patients (23%). Negative tests were more common in patients with risk factors, significantly so in those undergoing immunosuppressant therapy (50%) or with HIV infection (61%). Negative tests were less prevalent in patients with no risk factors (13%) and, among them, in children (1%), in patients between 15 and 29 years of age (10%) or in those with non-pulmonary forms (10%). Negative tests were significantly more prevalent among patients 60 to 74 years of age (27%), those over 74 (44%), and those whose disease was pulmonary and extrapulmonary (26%) or disseminated (64%). No significant differences in induration size of positive skin tests were observed for patients with and without risk factors (including HIV infection or non-infection). A normal distribution of induration size was observed in all groups. CONCLUSIONS: A negative tuberculin skin test for initial assessment should be interpreted in function of the presence or absence of risk factors, age, location or extension of tuberculosis. When a skin test is positive, the response will be similar whether or not an immunodepressant factor is present.

Adolescent↗

PubMed2002

Tuberculosis in Spain: epidemiological pattern and clinical practice.

SETTING: Thirteen Autonomous Regions in Spain. OBJECTIVE: To study the incidence of all forms of tuberculosis (TB) and investigate clinical practice in TB. DESIGN: Cases of all forms of tuberculosis diagnosed in the study setting from May 1986 to April 1997 were identified though active search of different databases. Clinical and epidemiological information on cases was collected from clinical records or by interview with physicians. RESULTS: The overall incidence of all forms of tuberculosis was 38.5/100,000 and the incidence of smear-positive disease was 13.83/100,000. Most cases (97.1%) were Spanish nationals, with rates higher in men than in women (52.7/100,000 vs. 24.87/100,000) and in groups aged 25-34 and 75 years and over (61.35/100,000 and 59.35/100,000, respectively). Disseminated forms were frequent (6.6%), and the most common risk factor was human immunodeficiency virus (HIV) infection (17.7% of cases). Hospitalisation was common (71.6%). Microbiological confirmation of diagnosis was sought for 87.7% of the cases (91.8% of pulmonary vs. 75.5% of extra-pulmonary cases), and 65.2% were culture-positive (73.8% of pulmonary vs. 39.7% of extra-pulmonary cases). HIV-infected patients were treated in almost equal proportions with three or four drugs (49.7% and 48.2%, respectively), while HIV-negative cases or those whose HIV status was unknown were usually treated with three drugs. CONCLUSION: The epidemiological pattern of TB in Spain is different to other industrialised countries in the age distribution of cases and the proportions of foreigners and cases with HIV infection. Microbiological confirmation of diagnosis is more common in pulmonary than in extra-pulmonary disease, and treatment with four drugs more frequent in HIV-positive cases.

Adolescent↗

PubMed2001

The sequence of a 15 769 bp segment of Pichia anomala identifies the SEC61 and FBP1 genes and five new open reading frames.

We have determined the sequence of a 15 769 bp DNA segment of Pichia anomala. The sequence contains seven complete open reading frames (ORFs) longer than 100 amino acids and a putative tRNA gene. Two of the ORFs code for the well-characterized genes SEC61 (which codes for the core subunit of the ER translocation complex) and FBP1 (encoding fructose-1,6-bisphosphatase). A gene coding for a protein similar to S. cerevisiae YDL054c was found between the two genes. These three genes show a different organization (intermingled triples) in three yeast species: Saccharomyces cerevisiae, Candida albicans and P. anomala. Two out of the four remaining ORFs show weak homology with different proteins from other species and the other two show non-significant similarity with previously sequenced genes. The nucleotide sequence has been submitted to the EMBL database under Accession No. AJ306295.

Amino Acid Sequence↗

PubMed2001

Analysis of 41 kb of the DNA sequence from the right arm of chromosome II of Schizosaccharomyces pombe.

We report the complete sequence of cosmid c18A7 (41 046 bp insert), located on the right arm of chromosome II of the Schizosaccharomyces pombe genome. The sequence, which partially overlaps with cosmids SPBC4F6 and SPBC336, contains 16 open reading frames (ORFs) capable of coding for proteins of at least 100 amino acid residues in length (one partial) and one small nucleolar RNA (snoRNA). Four known genes were found: swi10 (encoding a mating-type switching protein also involved in nucleotide excision repair); dim1 (encoding a dimethyladenosine transferase); arf1 (encoding ADP-ribosylation factor 1); and pol3 (cdc6) the partial fragment, encoding the 125 kDa catalytic subunit of the DNA polymerase type B. Six ORFs similar to known proteins were found. They include a transporter of the major facilitator superfamily class, a vacuolar sorting protein, an asparagine synthase, a nuclear protein, a reticulum oxidoreductin and a heat shock protein. Each protein product of the other six ORFs has conserved domains and can be assigned a molecular, but not a biological, function. The sequence has been submitted to the EMBL database under Accession No. AL080287.

Amino Acid Sequence↗

PubMed2001

Two-stage cultures for the production of astaxanthin from Haematococcus pluvialis.

A two-stage culture system was established for the production of astaxanthin from Haematococcus pluvialis. In a first stage green vegetative cells were produced in semicontinuous cultures maintained with daily renewal rates between 10 and 40%. The steady-state cell density decreased with increasing renewal rates. Highest cell productivity, 64 x 10(6) cells l(-1) day(-1) was obtained with a daily renewal rate of 20%. In a second stage the harvested cultures were submitted to high light (240 micromol photon m(-2) s(-1)) under batch conditions for 15 days in order to stimulate the transition to the aplanospore stage and the accumulation of astaxanthin. No decrease in cell density was recorded during the induction period in any of the cultures. Cultures obtained at high renewal rates continued growing during the induction period and no astaxanthin was accumulated until all nitrogen in the media had been consumed. The final concentration of astaxanthin was inversely correlated to the growth rate at which first-stage cultures were maintained. Optimal renewal rate for maximal astaxanthin production depended on the duration of the induction period. After a 12-day induction period the highest astaxanthin production, 5.8 mg l(-1) of semi-continuous culture day -1, was obtained with cultures maintained at a renewal rate of 20%. When the induction period was increased to 15 days maximal astaxanthin productivity, 9.6 mg l(-1) of semi-continuous culture day -1, was obtained from cultures maintained at a renewal rate of 40% despite the much lower astaxanthin concentration achieved in these cultures. Results demonstrate the feasibility of semi-continuous cultivation of H. pluvialis for the two-stage production of astaxanthin.

Chlorophyta↗

PubMed2001

Gene order in a 10 275 bp fragment of Yarrowia lipolytica, including adjacent YlURA5 and YlSEC65 genes conserved in four yeast species.

We have determined the sequence of a 10275 bp DNA segment of Yarrowia lipolytica located on chromosome VI. The sequence contains six complete open reading frames (ORFs) longer than 100 amino acids and two more partial ORFs at both ends. Two of the ORFs encode for the well-characterized genes YlURA5 (orotate phosphoribosyltransferase) and YlSEC65 (encoding a subunit of the signal recognition particle). These two genes show an identical organization-located on opposite strands and in opposite orientations-in four yeast species: Saccharomyces cerevisiae, Kluyveromyces lactis, Candida albicans and Y. lipolytica. One ORF and the two partial ORFs code for putative proteins showing significant homology with proteins from other organisms. YlVI-108w (partial) and YlVI-103w show 39% and 54% identity, respectively, with YDR430c and YHR088w from S. cerevisiae. YlVI-102c (partial) shows significant homology with a matrix protein, lustrin A from Haliotis rufescens, and with the PGRS subfamily (Gly-rich proteins) of Mycobacterium tuberculosis. The three remaining ORFs show weak or non-significant homology with previously sequenced genes. The nucleotide sequence has been submitted to the EMBL database under Accession No. AI006754.

Amino Acid Sequence↗

PubMed2001

Gas chromatographic study of the volatile products from co-pyrolysis of coal and polyethylene wastes.

The aim of this study was to determine the volatile products distribution of co-processing of coal with two plastic wastes, low-density polyethylene from agriculture greenhouses and high-density polyethylene from domestic uses, in order to explain the observed decrease in coal fluidity caused by polyethylene waste addition. Polymeric materials, although they are not volatile themselves, may be analysed by gas chromatography through the use of pyrolysis experiments. In this way, a series of pyrolysis tests were performed at 400 and 500 degrees C in a Gray-King oven with each of the two plastic wastes, one high-volatile bituminous coal and blends made up of coal and plastic waste (9:1, w/w, ratio). The pyrolysis temperatures, 400 and 500 degrees C, were selected on the basis of the beginning and the end of the coal plastic stage. The organic products evolved from the oven were collected, dissolved in pyridine and analysed by capillary gas chromatography using a flame ionization detector. The analysis of the primary tars indicated that the amount of n-alkanes is always higher than that of n-alkenes and the formation of the alkenes is favoured by increasing the pyrolysis temperature. However, this effect may be influenced by the size of the hydrocarbon. Thus, the fraction C17-C31 showed a higher increase of n-alkenes/n-alkanes ratio than other fractions. On the other hand, the difference between the experimental and estimated values from tars produced from single components was positive for n-alkanes and n-alkenes, indicating that co-pyrolysis of the two materials enhanced the chemical reactivity during pyrolysis and produced a higher conversion than that from individual components.

Alkanes↗

PubMed2001

Human securin, hPTTG, is associated with Ku heterodimer, the regulatory subunit of the DNA-dependent protein kinase.

We have previously isolated the hpttg proto-oncogene, which is expressed in normal tissues containing proliferating cells and in several kinds of tumors. In fact, expression of hPTTG correlates with cell proliferation in a cell cycle-dependent manner. Recently it was reported that PTTG is a vertebrate analog of the yeast securins Pds1 and Cut2, which are involved in sister chromatid separation. Here we show that hPTTG binds to Ku, the regulatory subunit of the DNA-dependent protein kinase (DNA-PK). hPTTG and Ku associate both in vitro and in vivo and the DNA-PK catalytic subunit phosphorylates hPTTG in vitro. Furthermore, DNA double-strand breaks prevent hPTTG-Ku association and disrupt the hPTTG-Ku complexes, indicating that genome damaging events, which result in the induction of pathways that activate DNA repair mechanisms and halt cell cycle progression, might inhibit hPTTG-Ku interaction in vivo. We propose that hPTTG might connect DNA damage-response pathways with sister chromatid separation, delaying the onset of mitosis while DNA repair occurs.

Animals↗

PubMed2001

Multicenter randomized study comparing initial daily induction with high dose lymphoblastoid interferon vs. standard interferon treatment for chronic hepatitis C.

One hundred fifty-five chronic hepatitis C patients were assigned at random to receive natural lymphoblastoid interferon (IFN)alpha-n1, s.c., for 13 months in one of three treatment regimens: initial daily induction with 10 million units (MU) followed (group 1, n = 50) or not (group 2, n = 52) by 1 month of rest and then three times weekly 10 MU (2 months), 5 MU (2 months), and 3 MU (8 months); group 3 (n = 53) received tiw 5 MU (2 months) followed by 3 MU (11 months). By intention-to-treat analysis, ALT normalization at completion of treatment was greater in patients who received continuous IFNalpha-n1 therapy with initial daily induction (group 2: 24/52, 46%) compared with those given intermittent therapy with initial daily induction (group 1: 17/50, 34%) and those who received standard IFNalpha-n1 therapy (group 3, 18/53, 34%; P not significant). The sustained ALT response was 26%, 27% and 21% and the sustained virological response was 20%, 27%, and 19%, in groups 1, 2, and 3, respectively. A trend was observed towards a higher biochemical and virological end-of-treatment response in patients given induction therapy (17%) compared with standard therapy (6%, P = 0.053). Sustained biochemical and virological responses were 20%, 27%, and 17% in groups 1, 2, and 3, respectively. Platelet and leukocyte counts decreased following daily high-dose treatment and remained low until therapy cessation (P < 0.001). The data suggest that daily s.c. induction with 10 MU IFNalpha-n1 followed by intermittent or continuous maintenance therapy for 1 year does not improve the results achieved with the standard 1-year IFNalpha course in the treatment of chronic hepatitis C patients.

Adolescent↗

PubMed2001

Community-based seroepidemiological survey of HCV infection in Catalonia, Spain.

The objective of this study was to investigate the prevalence of antibodies against the hepatitis C virus (anti-HCV) and the associated risk factors in a representative sample of the population of Catalonia, Spain. Serum samples from 2,142 subjects aged between 5 and 70 years, selected at random from urban and rural habitats, were studied. Multiple logistic regression analysis was carried out to determine variables associated independently with the presence of HCV antibodies. The age and gender standardized prevalence of anti-HCV was 2.5% (95% confidence interval, 1.8-3.2). Prevalence increased significantly with age (P < 0.001), but no other sociodemographic variables were associated with HCV infection. Tattoos (OR: 6.2), blood transfusions (OR: 5.0) intravenous drug use (OR: 4.9) and antecedents of hospitalization (OR: 2.3) were variables associated independently with infection. HCV infection affects mainly elderly people in Spain and spares children and adolescents. This suggests that major exposure to HCV may have occurred many years ago, when infection was more widespread than in recent years.

Adolescent↗

PubMed2001

Factors affecting the morphogenetic switch in Yarrowia lipolytica.

Yarrowia lipolytica is a dimorphic yeast usually isolated from dairy products. Here we described methods for inducing in a homogeneous way a true yeast-hypha transition in liquid medium. As a first step, the cells must be synchronized in the G1 phase of the cell cycle by nitrogen starvation. Using either N-acetylglucosamine (GlcNAc) or serum as the only carbon sources, more than 90% of the cells form hypha after 4-6 h of incubation. Bovine albumin is also able to induce the yeast-hypha transition, although to a lesser extent. The addition of glucose to cultures growing with GlcNAc arrest the morphogenetic switch but not when added to cultures growing in the presence of serum. Serum also induces invasive growth in solid medium. Neither pH, nitrogen starvation, nor temperature play a relevant role in the morphogenetic switch. Our results suggest that, as occurs in Candida albicans, at least two morphogenetic signal pathways exist in Y. lipolytica.

Acetylglucosamine↗

PubMed2001

Growth Rate of the microalga Tetraselmis suecica changes the biochemical composition of Artemia species.

The impact of different microalgal semicontinuous cultures on growth and biochemical composition in the next link of the food chain was tested using the filter feeder Artemia species as a model. The marine microalga Tetraselmis suecica was cultured semicontinuously with renewal rates between 10% and 50% and used to feed Artemia. Microalgal cultures maintained with a low renewal rate that had biochemical composition similar to that of the stationary-phase cultures commonly used in aquaculture produced poor growth and survival and low food-conversion efficiency compared to cultures maintained with a high renewal rate. Changes in the renewal rate in microalgal cultures also resulted in important changes in the gross biochemical composition of the filter feeder. The gross biochemical composition of the Artemia resembled that of the microalgae used as food except for total lipid content. The percentage of protein in the organic fraction of Artemia increased from 45% to 65% of the organic weight with increasing renewal rates in the microalgal cultures, while the carbohydrate percentage decreased under the same conditions. Higher renewal rates resulted in higher lipid percentages in the microalga, but in Artemia the percentage of lipids decreased from 19% of the organic weight with a renewal rate of 10%, to 13% with a renewal rate of 50%. The percentage of all polyunsaturated fatty acids in Artemia, including 20:5n-3, increased slightly with increasing renewal rates in the microalgal cultures. Results emphasize the importance of controlling microalgal nutritional value for the success of aquaculture food chains in which filter feeders are involved.

Journal Article↗

PubMed2001

[Creatine kinase increases after coronary interventions].

INTRODUCTION AND OBJECTIVES: Percutaneous revascularization has led to an important change in the treatment of patients with symptomatic ischemic heart disease in recent years. There is controversy concerning the incidence and prognostic significance of postprocedural increases in creatine kinase. The aim of this study was to assess the incidence of these elevations and the related factors and to observe the prognosis of patients with and without creatin kinase elevations. METHODS: We reviewed 447 patients in whom an angioplasty was done in our department from January 1997 to June 1998, excluding 138 patients with myocardial infarction in the previous four days or unsuccessful angioplasty. Creatine kinase was measured in all patients at 0, 4, 8 and 24 hours after angioplasty. We analyzed the incidence of elevated levels of creatine kinase following coronary surgery and the characteristics of the patients in comparison with a control group made up of patients who, at a similar time had undergone a similar angioplasty procedure including, a similar vessel and type of lesion, and equivalent left ventricular function but without elevated serum levels of creatine kinase. Major adverse coronary events were defined as: cardiac death, nonfatal myocardial infarction, new revascularization and unstable angina in which hospitalization was required. RESULTS: Out of 309 patients studied, an elevation in creatine kinase was observed in 24 patients (7.7%). Complications related to the procedure were found in 50% of these elevations, most of which involved side branch occlusion. There were no differences with respect to the demographical or anatomical characteristics of the lesions in the groups studied. During the follow-up of 9.5 months, complications were observed in 37.5% of the group of patients with elevated creatine kinase levels and in 20% of the control group, but this difference did not achieve statistical significance. CONCLUSIONS: Creatine kinase elevations are produced in 7.7% of the patients after coronary angioplasty. Complications related to the procedure were observed in 50% of the cases, most being side branch occlusion and no complications were seen in the remaining patients. Continuous measurement of creatine kinase after angioplasty shows a low sensitivity for detecting complications during follow-up. New, more sensitive and specific cardiac markers, such as troponin, could define this group of patients.

Angioplasty, Balloon, Coronary↗