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Biomedical subjects

G Pérez

Publications and source records attributed to G Pérez.

At least 19 recordsLinked to original sources
PubMed2006

Trypanosomiasis in Venezuelan water buffaloes: association of packed-cell volumes with seroprevalence and current trypanosome infection.

The seroprevalence of trypanosomiasis and the prevalence of current trypanosome infection in water buffaloes from the most important livestock areas of Venezuela were evaluated by IFAT and the microhaematocrit centrifugation technique, respectively. The usefulness of a PCR-based assay for identifying the trypanosome species in the buffaloes was also evaluated. Of the 644 animals investigated, 40 (6.2%) were found infected with trypanosomes by blood centrifugation, and 196 (30.4%) were found positive for anti-trypanosome antibodies, by IFAT. The results of the PCR-based assay indicated that 92.5% of the animals with current infections were infected with Trypanosoma vivax and the rest with T. theileri (the first molecular confirmation of T. theileri in Venezuelan water buffaloes). The national programme to treat and prevent trypanosome infections in the buffaloes does not appear to be meeting with great success, even though it is focused on T. vivax. Although the level of parasitaemia was categorized as low for 28 (70%) of the infections detected (and packed-cell volumes appeared to be unassociated with IFAT result, and uncorrelated, in the infected animals, with level of parasitaemia), the 40 infected buffaloes had a significantly lower mean packed-cell volume than the uninfected animals (P<0.05). Farmers should therefore be made aware of the probability of trypanosome-attributable losses in buffalo productivity.

Animals↗
PubMed2006

Antioxidant status in patients with sleep apnoea and impact of continuous positive airway pressure treatment.

The episodes of hypoxia/re-oxygenation associated with the respiratory disturbances observed in patients with obstructive sleep apnoea syndrome (OSAS) may induce the generation of oxygen free radicals. Indeed, several studies suggest that OSAS is associated with oxidative stress. The present study tested the hypothesis that patients with OSAS have an alteration in antioxidant defences. The plasma levels of total antioxidant status (TAS), glutathione peroxidase (GPX), gamma-glutamyltransferase (GGT), vitamins A, E, B12 and folate, and homocysteine were determined in 47 patients with OSAS and 37 healthy subjects. Of these, 27 patients who used continuous positive airway pressure (CPAP) for >4 h.night-1 were re-examined 12 months later. Patients with OSAS had lower TAS (1.4+/-0.16 versus 1.50+/-0.10 mmol.L-1), vitamin A (64+/-19 versus 74+/-17 microg.dL-1) and vitamin E levels (1,525+/-499 versus 1,774+/-503 microg.dL-1), and increased values of GGT (42+/-22 versus 32+/-16 U.L-1) than controls. There was no difference between groups in GPX, homocysteine, vitamin B12 and folate plasma levels. CPAP treatment normalised the levels of TAS (1.50+/-0.13 mmol.L-1) and the activity of GGT (30+/-14 U.L-1) without any influence on vitamins levels. In conclusion, the results indicate that patients with obstructive sleep apnoea syndrome have a decreased antioxidant capacity that is partially reversed by continuous positive airway pressure treatment.

Adult↗
PubMed2004

Determination of pollution trends in an abandoned mining site by application of a multivariate statistical analysis to heavy metals fractionation using SM&T-SES.

The mobility, availability and persistence of Heavy Metals (HMs), As, Cd, Cu, Ni, Pb and Zn, in contaminated soils of a former abandoned mining area were evaluated by means of a sequential extraction scheme (SES) and applying a multivariate statistical analysis to the obtained data. Chemical partitioning of HMs in each sample was determined in four fractions (acid-soluble, reducible, oxidable and residual) following the Standard Measurements and Testing (SM&T) SES, formerly BCR-SES. Statistical evaluation of results by pattern recognition techniques allowed identification of groups of samples with similar characteristics and observations of correlations between variables, determining the pollution trends and distribution of HMs within the studied area. Typical metal-fraction association and metal availability characteristics of heavy metals have been depicted. The obtained results indicate an urgent need to attenuate the hazard in that area posed by high concentrations of toxic metals, which exceed the limits specified by different European legislations on soil reclamation.

Chemistry Techniques, Analytical↗
PubMed2002

Random amplified polymorphic DNA analysis for differentiation of Leuconostoc mesenteroides subspecies isolated from Tenerife cheese.

AIMS: In the present study, a RAPD-PCR fingerprinting method was developed to assign Tenerife cheese Leuconostoc mesenteroides strains to its three subspecies (mesenteroides, cremoris and dextranicum). METHODS AND RESULTS: Arbitrarily primed-PCR gave different DNA banding patterns for each type strain of Leuc. mesenteroides subspecies consisting in three major and intense bands of: 1800, 1600 and 1150 bp for subspecies mesenteroides 1800, 1150 and approximately 350 bp for subspecies cremoris; and 1800, 1600 and 1500 bp for subspecies dextranicum. DNA fingerprints of Tenerife cheese Leuc. mesenteroides subspecies were coincident to that of their respective type strain. RAPD profiles were reproducible with DNA template obtained by two different extraction methods. CONCLUSIONS: Tenerife cheese Leuc. mesenteroides strains were rapidly and unequivocally assigned to one of the subspecies by comparing their RAPD-PCR fingerprints with those displayed by type strains used as standards. This technique can be applied to complement preliminary identification of Leuc. mesenteroides to the species level by other molecular methods such as protein fingerprinting. SIGNIFICANCE AND IMPACT OF THE STUDY: RAPD-PCR allows reliable, reproducible and rapid molecular differentiation of Tenerife cheese Leuc. mesenteroides subspecies with no need to use time-consuming and often ambiguous biochemical tests.

Bacterial Typing Techniques↗
PubMed2002

FDG-PET improves the management of patients with suspected recurrence of colorectal cancer.

This study aims to assess the influence of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) detection of recurrent disease on the management of patients with colorectal cancer and suspected recurrence. One hundred and twenty patients with suspected recurrence were studied with FDG-PET. Fifty-eight patients were referred for FDG-PET because of the elevation of serum tumour markers. Thirty-one patients were referred because of inconclusive results of conventional imaging modalities. Twenty-five patients had known recurrence and were referred for pre-surgical assessment. Six patients were referred because of abdominal pain. A major management change was considered when, as a consequence of FDG-PET results, medical treatment was changed to surgical, or surgical to medical or to no treatment. A minor management change was considered when changes were made within a treatment modality. Of the 58 patients with elevated serum carcinoembryonic antigen (CEA), FDG-PET detected recurrence and led to a major management change in 34 (58%). Eighteen underwent curative surgery and 16 were treated with systemic therapy. Of the 31 patients evaluated because of inconclusive results of conventional imaging modalities, FDG-PET was positive for recurrence in 24 and negative in seven. A major management change took place in 14 patients (45%). Of the 25 patients evaluated to rule out other sites of disease before surgery, FDG-PET did not show any other site of recurrence in 13 (52%) and showed more lesions in the remaining patients. Major management change took place in eight patients (32%). Overall, in the 120 patients studied, FDG-PET resulted in major management changes in 58 (48%), minor changes in four (3%) and no change in 54 (45%). It can be concluded that FDG-PET has a significant impact on the management of patients with suspected recurrence of colorectal cancer. FDG-PET detection of recurrence frequently allows curative surgical intervention. The early identification of distant metastases may also facilitate the implementation of systemic treatment.

Abdomen↗
PubMed2002

Vitamins and mineral intake in elderly people from Extremadura.

To evaluate the vitamin and mineral consumption of a group of elderly people of the Comunidad of Extremadura. 122 subjects 62.5+/-5.3 years (64 women, 57 men) responded to a survey on their food intake the day before. The vitamin and mineral intake was calculated using a computer program from the University of Granada. We found no statistically significant differences by gender in the intake of the following vitamins: niacin (24.5+/-10.1 vs 25.6+/-9.7 mg/day), B1 (1.6+/-0.6 vs 1.7+/-0.6 mg/day), B6 (1.7+/-0.6 vs 1.8+/-0.5 mg/day), C (129.5+/-82.1 vs 158.1+/-97.6 mg/day), D (4.4+/-7.5 vs 3.8+/-6.5 microg/day), E (7.8+/-4.1 vs 8.1+/-3.8v mg/day), and folic acid (326.6+/-164.0 vs 383.1+/-215.3 microg/day). We did find statistically significant differences in the intake of the vitamins: A (582.2+/-299.6 vs 771.8+/-602.2 microg/day, p<0.05), B12 (23.4+/-20.3 vs 13.1+/-12.1 microg/day, p<0.001) and B2 (1.6+/-0.4 vs 1.8+/-0.5 mg/day, p<0.05). With respect to mineral intake, we found no statistically significant differences by gender in the intake of the following minerals: calcium (1046.8+/-276.9 vs 1088.9+/-307.7 mg/day), iron (20.2+/-6.6 vs 18.5+/-8.6 mg/day), iodine (73.6+/-37.9 vs 73.8+/-41.1 mg/day), potassium (2804.6+/-1088 vs 2837.5+/-1035.8 mg/day), magnesium (405.4+/-155.3 vs 366.5+/-141.3 mg/day), phosphorus (1407.4+/-408.6 vs 1317.2+/-447.2 mg/day) and zinc (8.9+/-3.3 vs 8.0+/-2.7 mg/day). We found a statistically significant difference (p<0.05) for sodium (2124.9+/-1049.5 mg/day in men and 1728.4+/-992.5 mg/day in women). Our results showed an intake less than the RDA of vit.A, while the vit.B12 intake was greater than the RDA. The intake of the other parameters fitted the recommended values.

Aged↗
PubMed2002

Bioavailability of ranitidine in healthy Mexican volunteers: effect of food.

Is well known that food can affect the bioavailability of several drugs, its impact is major for those drugs that have to act near of drug absorption. Documentation about alterations of ranitidine bioavailability by effect of food is poor. The purpose of this work was to evaluate the effect of food over the bioavailability of ranitidine. Twenty healthy Mexican volunteers were included for the study. The study was made in two stages, in the first one the volunteers had 12 hour fast and took a 300 mg of oral dose of ranitidine (without food, WOF) and blood samples were drawn. Two weeks later, the volunteers took a normal diet just before ranitidine intake (with food, WF). The area under the curve (AUC) was 30% greater in WOF, Cmax was 921.5 ng/ml (WF) vs. 1685.2 (WOF), and t1/2 was 2.70 +/- 1.38 (WF) h vs 3.66 +/- 1.34 (WOF). The AUC, Cmax and t1/2 were statistically different. It is evident that there are differences in the drug disposition due to the presence of food, then, it is possible that the efficacy of ranitidine as inhibitor of gastric secretion being limited by food.

Adolescent↗
PubMed2001

Clinical significance of donor-unrecognized bacteremia in the outcome of solid-organ transplant recipients.

We evaluated the clinical significance of unrecognized bacteremia in the organ donor (i.e., blood culture results that were reported to be positive after transplantation) on the outcome of transplant recipients. Twenty-nine of 569 liver and heart donors (5%) had bacteremia at the time of organ procurement, but there were no documented instances of transmission of the isolated bacteria from the donor to the recipient. Unrecognized bacteremia in the donor does not have a negative clinical impact on the outcome of organ transplant recipients.

Adolescent↗
PubMed2001

Stochastic analog to phase transitions in chaotic coupled map lattices.

Stochastic dynamical systems are shown to exhibit the same order-disorder phase transitions that have been found in chaotic map lattices. Phase diagrams are obtained for diffusively coupled two-dimensional (2D) lattices, using two stochastic maps and a chaotic one, for both square and triangular geometries, with simultaneous updating. We show how the use of triangular geometry reduces (or even eliminates) the reentrant behavior found in the phase diagrams for the square geometry. This is attributed to the elimination (via frustration) of the antiferromagnetic clusters common to simultaneous updating of square lattices. We also evaluate the critical exponents for the stochastic maps in the triangular lattices. The strong similarities in the phase diagrams and the consistency between the critical exponents of one stochastic map and the chaotic one, evaluated in an early work by Marcq et al. [Phys. Rev. Lett. 77, 4003 (1996); Phys. Rev. E 55, 2606 (1997)] suggest that the "sign-persistence," defined as the probability that the local map keeps the sign of the local variable in one iteration, plays a fundamental role in the presence of continuous phase transitions in coupled map lattices, and is a basic ingredient for models that belong to this weak Ising universality. However, the fact that the second stochastic map, which has an extremely simple local dynamics, seems to fall in the 2D Ising universality class, suggests that some minimal local complexity is also needed to generate the specific correlations that end up giving non-Ising critical behavior.

Journal Article↗
PubMed2001

Effect of Mangifera indica L. extract (QF808) on protein and hepatic microsome peroxidation.

The antioxidant activities of QF808, a steam bark extract of Mangifera indica L., were studied on hydroxyl-mediated oxidation of bovine serum albumin (BSA) and in a hepatic microsome system. The extract was effective in reducing the oxidation of BSA, since its half- maximal inhibition concentration (IC(50)) was 0.0049% w/v in the inhibition of carbonyl group formation and lower than 0.0025% w/v in the inhibition of sulfhydryl group loss. QF808 inhibited lipid peroxidation which was initiated enzymatically by reduced nicotinamide adenine dinucleotide phosphate (NADPH), IC(50)= 0.00075% w/v, or non-enzymatically by ascorbic acid, IC(50) = 0.0126% w/v. The extract tested did not inhibit NADPH-dependent cytochrome P-450 reductase activity, since it had no effect on the oxidation rate of NADPH. These results suggest that QF808 has an antioxidant activity, probably due to its ability to scavenge free radicals involved in microsome lipid peroxidation. In addition, QF808 antioxidant profile in vitro is probably similar to its principal polyphenolic component, mangiferin, a glycosylated xanthone.

Animals↗
PubMed2001

Disturbance of cellular iron uptake and utilisation by aluminium.

Aluminium (Al) affects erythropoiesis but the real mechanism of action is still unknown. Transferrin receptors (TfR) in K562 cells are able to bind Tf, when carrying either iron (Fe) or Al, with similar affinity. Then, the aim of this work was to determine whether Al could interfere with the cellular Fe uptake and utilisation. K562 cells were induced to erythroid differentiation by either haemin (H) or sodium butyrate (B) and cultured with and without Al. The effect of Al on cellular Fe uptake, Fe incorporation to haem and cell differentiation was studied. H- and B-stimulated cells grown in the presence of 10 microM Al showed a reduction in the number of haemoglobinised cells (by 18% and 56%, respectively) and high amounts of Al content. Al(2)Tf inhibited both the (59)Fe cellular uptake and its utilisation for haem synthesis. The removal of Al during the (59)Fe pulse, after a previous incubation with the metal, allowed the cells to acquire Fe quantities in the normal range or even exceeding the amounts incorporated by the respective control cells. However, the Fe incorporated to haem could not reach control values in B-stimulated cells despite enough Fe acquisition was observed after removing Al. Present results suggest that Al might exert either reversible or irreversible effects on the haemoglobin synthesis depending on cellular conditions.

Aluminum↗
PubMed2001

Psychometric properties of the Temperament and Character Inventory (TCI) questionnaire in a Spanish psychiatric population.

OBJECTIVE: The psychometric properties of the Spanish version of Cloninger's Temperament and Character Inventory (TCI) were examined in a psychiatric population. METHOD: Internal consistency, factor structure and concurrent validity were studied in a sample of 416 psychiatric patients. RESULTS: A moderate to high internal consistency for all personality dimensions was found, except for Persistence. A confirmatory factor analysis of the TCI performed at the subscale level revealed an uncertain factor structure. However, when analysed separately, both the 11 temperament subscales (plus Persistence) and the 13 character subscales shaped four and three factors, respectively, in agreement with the biosocial model of personality. Finally, concurrent validity analyses were conducted using EPQ, SPSR and SSS questionnaires showing results consistent with theory. CONCLUSION: The Spanish version of the TCI is a reliable and valid instrument, although the Persistence dimension might require further revision.

Adult↗
PubMed2001

Relationship between monokaryotic growth rate and mating type in the edible basidiomycete Pleurotus ostreatus.

The edible fungus Pleurotus ostreatus (oyster mushroom) is an industrially produced heterothallic homobasidiomycete whose mating is controlled by a bifactorial tetrapolar genetic system. Two mating loci (matA and matB) control different steps of hyphal fusion, nuclear migration, and nuclear sorting during the onset and progress of the dikaryotic growth. Previous studies have shown that the segregation of the alleles present at the matB locus differs from that expected for a single locus because (i) new nonparental B alleles appeared in the progeny and (ii) there was a distortion in the segregation of the genomic regions close to this mating locus. In this study, we pursued these observations by using a genetic approach based on the identification of molecular markers linked to the matB locus that allowed us to dissect it into two genetically linked subunits (matBalpha and matBbeta) and to correlate the presence of specific matBalpha and matA alleles with differences in monokaryotic growth rate. The availability of these molecular markers and the mating type dependence of growth rate in monokaryons can be helpful for marker-assisted selection of fast-growing monokaryons to be used in the construction of dikaryons able to colonize the substrate faster than the competitors responsible for reductions in the industrial yield of this fungus.

Alleles↗
PubMed2000

[Hematopoietic stem cell transplantation as salvage treatment in patients with aggressive non-Hodgkin's lymphoma].

BACKGROUND: The indication of early hematopoietic stem cell transplantation (HSCT) in patients with aggressive non-Hodgkin's lymphoma (LNH) is controversial. PATIENTS AND METHODS: Retrospective analysis of 86 patients with aggressive NHL treated with MACOP/VACOP-B chemotherapy. HSCT was performed as salvage treatment to patients under 65 years of age with progressive disease or chemosensitive relapse. Progression free survival (PFS) and overall survival (OS) were determined by the Kaplan-Meier method. Rates of response and survival functions were compared between the International Prognostic Index (IPI) groups using the Chi-square and log-rank tests, respectively. RESULTS: Patients median age was 48 years; 22% had T cell NHL and 57% had intermediate-high and high risk (high risk) IPI. There were 6 toxic deaths (7%), and treatment failure was observed in 42 patients (48.8%). Thirty one of them were candidates for TPH due to age under 65 years, although 21 were finally transplanted (including 13 with high risk IPI). A significant association between PFS and IPI was observed, 61.9% for low risk (low and low-intermediate) versus 28.2% for high risk groups (p = 0.0007). With a median follow up of 4.8 years, OS was 64%; 80.5% for low risk versus 52.6% for high risk IPI groups (p = 0.01), and 83.7% versus 62% for the same groups in patients under 65 years of age (p = 0.02). The median follow up after failure to chemotherapy was 42.7 months. CONCLUSIONS: In this retrospective study, OS rate in high risk IPI patients with NHL using HSCT as salvage treatment is similar to that reported using HSCT during earlier phases of treatment.

Adolescent↗
PubMed2000

Evaluation of the in vitro antioxidant activity of Mangifera indica L. extract (Vimang).

An extract of Mangifera indica L. (Vimang) was tested in vitro for its antioxidant activity using commonly accepted assays. It showed a powerful scavenger activity of hydroxyl radicals and hypochlorous acid and acted as an iron chelator. The extract also showed a significant inhibitory effect on the peroxidation of rat-brain phospholipid and inhibited DNA damage by bleomycin or copper-phenanthroline systems.

Animals↗
PubMed2000

Chagas' disease of the cervix uteri in a patient with acquired immunodeficiency syndrome.

A 27-year-old woman with the acquired immunodeficiency syndrome and endocervical Chagas' disease is reported. The patient was a cocaine addict, and her sexual partner was also human immunodeficiency virus (HIV)-positive. Her past medical history included a son who died 3 days after birth due to congenital Chagas' disease. Seven years later, through a cervical biopsy, a reactivation of Chagas' disease was diagnosed. Giant cells with typical amastigotes were seen; they strongly stained with antibodies against Trypanosoma cruzi. The patient died 5 months later of an acute chagasic myocardiopathy. To our knowledge, this is the first report of this parasitosis in the cervix uteri.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Inequalities in mortality by social class in men in Barcelona, Spain.

Most of the studies of inequalities in mortality carried out in Spain have been ecological, due to the difficulty of obtaining good quality socioeconomic information at individual level. The objective of this study was to describe inequalities in mortality by social class, based on occupation, among men residents of Barcelona in 1993. A representative sample was obtained of men residents of Barcelona who died during the year 1993, aged between 15 and 65 years. It was a retrospective interview given to relatives of the deceased, or other closely related persons. The variables analysed were: age, education level, underlying cause of death, and social class based on occupation (manual and non-manual workers). Rates, relative risks (RRs) and their 95% confidence intervals (95% CIs) are presented by age groups and cause of death. The main results show that among young people, the excess of mortality due to infectious diseases is notable (RR: 1.9; 95% CI: 1.6-2.2), and also due to external causes (RR: 2.1; 95% CI: 1.8-2.4) among manual workers with respect to non-manual workers, mainly due to AIDS and drug overdose. No significant differences were found in mortality due to tumours. For respiratory and cardiovascular causes, there is an increase in mortality in the less favoured social classes, as also occurs for mortality due to diseases of the digestive system, particularly among young manual workers, with an RR: 2.6 (95% CI: 1.5-3.6) compared to non-manual workers. This study shows that it is necessary to continue exploring inequalities in health, but above all it is necessary to implement efficient preventive measures addressed mainly at young people in situations of disadvantage, in order to avoid the excess of avoidable mortality which is found.

Adolescent↗