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Biomedical subjects

M Fuentes

Publications and source records attributed to M Fuentes.

At least 19 recordsLinked to original sources
PubMed2006

Design of a continuous wave blood flow bi-directional Doppler system.

This paper describes the design of a continuous wave blood flow bi-directional Doppler system based on an open, high-resolution architecture that is portable and low cost. The system incorporates the advantages of expensive systems with dedicated hardware. The system is composed of a flow detector probe, a signal conditioning stage, a direction detection module, a signal processing stage and a graphic user interface. The direction detection of the signal is achieved using a fast digital phasing filter. The Doppler signal is processed using a short-time Fourier transform-based algorithm. This is commonly used as a reference. Nevertheless, the system allows us to incorporate alternative high-resolution spectral estimation methods that might offer more precise information to the specialist.

Algorithms↗
PubMed2006

Predictive factors for pressure ulcers in the ambulatory stage of spinal cord injury patients.

STUDY DESIGN: Case control study. OBJECTIVE: To determine the main risk factors for pressure ulcer (PU) in ambulatory spinal cord injury (SCI) patients. SETTING: Hospital del Trabajador, Santiago, (ACHS (Chilean Security Association), Chile. METHODS: We studied 41 patients for traumatic SCI, from Santiago, Chile, cared for in our hospital. The clinical histories were reviewed from first discharge to 1996. The patients were categorized into two groups: 18 cases with a previous history of PU, and 23 patients with no history of PU were considered as controls. Univariate analysis was performed, 18 variables per case, 10 of which were psychosocial factors. RESULTS: There were 37 men and four women. Average age was 41.7 years. Duration of SCI on average was 6.7 years. The distribution was complete paraplegia (CPP) 22 patients (54%), complete tetraplegia three patients (7%), incomplete paraplegia 11 patients (27%) and incomplete tetraplegia, five patients (12%). Four variables of the univariate analysis were significant: duration of cord injury (SCI time) >5 years, completeness of cord injury, paraplegia and not able to practice regular standing. There was a significant association in body morphology (endo or ectomorphic), being able to practice regular standing and personality disorder in CPP. CONCLUSIONS: The risk for developing PU was 4.3 times greater in CPP patients than is any other type of SCI. CPP patients who do not practice standing periodically, who have a personality disorder and have an ecto/endomorphic corporal morphology have a greater risk of suffering PU.

Adult↗
PubMed2006

Lack of association between the fatty acid binding protein 2 (FABP2) polymorphism with obesity and insulin resistance in two aboriginal populations from Chile.

The aim of this study was to assess the frequency of fatty acid binding protein 2 (FABP2) Ala54Thr genetic polymorphism and to evaluate its association with obesity and insulin resistance in Chilean aboriginal populations. A sample of 96 urban Aymara and 111 urban Mapuche subjects aged 20-80 years were recruited for this cross-sectional study. Glucose, insulin and lipid profile were measured in fasting plasma samples. Insulin resistance was estimated through the HOMA-IR model. FABP2 Ala54Thr genotypes were determined by PCR followed by RFLP analysis. The allele frequency of Thr54 variant was estimated as 18.2% in Aymara subjects, which is one of the lowest reported to date. The corresponding frequency in Mapuche subjects was 31.9% (p<0.002). Regarding genotype-phenotype associations, no significant differences were found in any of the anthropometric or metabolic variables according to Ala54Thr genotypes. After adjustment by BMI and metabolic variables through a logistic regression analysis, the association of the FABP2 polymorphism with ethnic group persisted (Mapuche group: OR=2.37, 95% CI 1.319-4.277, p=0.004) It is unlikely that Ala54Thr polymorphism of the FABP2 gene plays a relevant role in obesity and insulin resistance in Chilean ethnic groups.

Amino Acid Substitution↗
PubMed2005

Does an educational leaflet improve self-reported adherence to therapy in osteoporosis? The OPTIMA study.

INTRODUCTION: Adherence to treatment in osteoporosis remains poor. The aim of this study was to evaluate the effects of an educational leaflet on adherence to medication and to assess the association between adherence and health-related quality of life (HRQOL). METHODS: A naturalistic, observational, multi-center, prospective study of 12 months' follow-up was performed. Consecutive post-menopausal women aged 50 years to 86 years starting treatment with raloxifene according to daily practice were enrolled from 126 primary care offices in Spain. The women were assigned to two study groups. Group A received an educational leaflet with general information about osteoporosis; group B followed current practice. To assess adherence to medication and HRQOL, the Morisky test and the EuroQoL questionnaire were administered. A total of 745 post-menopausal women (group A, n=366; group B n=379), with a mean age of 62 years, were included. RESULTS: Most patients in both study groups showed high adherence to raloxifene at the 3-month visit: 56.3% vs 62.7% for groups A and B, respectively; this proportion at the 12-month visit was 47.4% (P=0.15) and 52.5% (P=0.02), respectively. At baseline, "pain/discomfort" was the dimension showing the highest percentage of women reporting problems: 86.4% vs 83.2% in groups A and B, respectively (P=0.22). HRQOL improved in both groups throughout the study, with an overall mean increment in the EuroQoL visual analog scale (EQ VAS) of 9.2 at 12 months (P<0.01). Correlations between adherence and HRQOL were weak. After receiving an educational leaflet, young post-menopausal women suffering osteoporosis did not show improvement in adherence to therapy. HRQOL improved at 12-month follow-up under treatment. CONCLUSION: No consistent correlation between adherence and HRQOL was found.

Aged↗
PubMed2004

Structural and ultrastructural alterations in BALB/c mice: effects of Penicillium citrinum metabolites.

The aims of this work were to determine the effect of feeding BALB/c mice a diet containing culture materials of a citrinin producing strain of Penicillium citrinum (Thom). Changes in hematological parameters, serum chemistry and histological changes in liver, kidney and heart were determined. After 60 days, control treated (CT) mice appeared normal in all respects, whereas, the mice fed the feeds supplemented with Penicillium (CMT) showed decreased weight gain, lower hematocrits, increased serum alanine aminotransferase (ALT) and clear signs of renal and hepatotoxicity based on histological changes. Changes observed in the liver of CMT mice included portal and lobular infiltration of polymorphonuclear cells, with concomitant hepatocellular necrosis, hepatic steatosis, prominent Kupffer's cells, hemosiderin granules in the cytoplasm of periportal hepatocytes and other lipid inclusions in the surrounding mitochondria were also observed. Our findings suggest that in vivo, P. citrinum Thom metabolites, which contain citrinin, could cause illnesses such as toxic hepatitis or intravascular hemolysis.

Animal Feed↗
PubMed2003

Antifungal activities of nine traditional Mexican medicinal plants.

Eighteen plant extracts from nine traditional Mexican medicinal plants were tested for antifungal activity against two dermatophyte fungal species (Trichophyton mentagrophytes and Trichophyton rubrum), one non-dermatophyte (Aspergillus niger), and one yeast (Candida albicans). The strongest effect was manifested by the hexane extracts from Eupatorium aschenbornianum and Sedum oxypetalum, as well as the methanol extracts from Lysiloma acapulcensis and Annona cherimolia.

Antifungal Agents↗
PubMed2003

Increased carotid artery intima-media thickness may be associated with stroke in primary antiphospholipid syndrome.

OBJECTIVE: To investigate the prevalence and clinical significance of carotid artery intima-media thickness (IMT) in patients with primary antiphospholipid syndrome (APS). METHODS: 28 patients with primary APS with at least a five year follow up, and 28 healthy subjects, matched by age and sex, were included in the study. Colour Doppler with high resolution B mode carotid ultrasonography and spectral analysis were performed in patients and controls. Information on cardiovascular risk factors and the clinical course were collected. RESULTS: The mean (SD) age of patients and controls (12 male, 16 female in each group) was 40 (8.5) years; the mean (SD) disease duration 7.7 (3) years. Carotid artery IMT was found in 23/28 patients (2.6 (1.14) mm) and 7/28 controls (1.2 (0.44)) (p=0.0001). A decrease in the lumen diameter was also found in 11/28 patients with primary APS without carotid atherosclerotic plaque, and 2/28 controls (p=0.004). Hyperlipidaemia, diabetes, smoking, obesity, and hypertension were not associated with carotid artery IMT. Patients with carotid artery IMT had arterial vascular disease more often than patients without: 9/23 v 0/5 (p<0.009). These patients had stroke (seven patients), myocardial infarction (one), and mesenteric thrombosis (one). Subjects with IMT had a threefold higher risk for stroke than those without IMT (95% CI 0.78 to 14.3). CONCLUSIONS: Patients with primary APS have a high prevalence of carotid artery IMT and a decreased lumen diameter. IMT in primary APS may be associated with stroke. Patients with primary APS with IMT must be considered as carriers of atherosclerosis.

Adult↗
PubMed2002

Dynamical effects induced by long range activation in a nonequilibrium reaction-diffusion system.

We show both experimentally and numerically that the time scales separation introduced by long range activation can induce oscillations and excitability in nonequilibrium reaction-diffusion systems that would otherwise only exhibit bistability. Namely, we show that in the chlorite-tetrathionate reaction, where the autocatalytic species H+ diffuses faster than the substrates, the spatial bistability domain in the nonequilibrium phase diagram is extended with oscillatory and excitability domains. A simple model and a more realistic model qualitatively account for the observed dynamical behavior. The latter model provides quantitative agreement with the experiments.

Journal Article↗
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↗
PubMed2001

Experimental evidence of stochastic resonance without tuning due to non-Gaussian noises.

In order to test theoretical predictions, we have studied the phenomenon of stochastic resonance in an electronic experimental system driven by white non-Gaussian noise. In agreement with the theoretical predictions our main findings are an enhancement of the sensibility of the system together with a remarkable widening of the response (robustness). This implies that even a single resonant unit can reach a marked reduction in the need for noise tuning.

Journal Article↗
PubMed2001

Panic and suicidal ideation in primary care.

The objective of this article is to examine the relationship between panic attacks, panic disorder, and suicidal ideation among primary care patients. A probability sample of 1,007 primary care attenders from a large urban university practice was assessed for current mental disorders and suicidal ideation (past 2 week prevalence) with the PRIME-MD Patient Health Questionnaire. Controlling for major depression, substance use disorders, and sociodemographic variables simultaneously, patients with either panic attacks or panic disorder had significantly increased risks of suicidal ideation. Suicidal ideation was highly associated with major depression and comorbid panic disorder (OR = 15.4) or panic attacks (OR = 7.9). There is need for detection and possible treatment of patients with panic attacks or disorder in primary care, especially among those with co-occurring major depression.

Adult↗
PubMed2001

Effect of budesonide and nedocromil sodium on IL-6 and IL-8 release from human nasal mucosa and polyp epithelial cells.

We investigated the effect of budesonide and nedocromil sodium on the secretion of IL-6 and IL-8 by cultured epithelial cells from healthy nasal mucosa and nasal polyps. Human epithelial cell conditioned media was generated with fetal calf serum (FCS) in the presence or absence of budesonide and/or nedocromil sodium. Budesonide inhibited FCS-induced IL-6 and IL-8 release in a dose-dependent manner. The IC25 (25% inhibitory concentration) of budesonide on IL-6 release was higher in nasal polyp than in nasal mucosa epithelial cells (34 nM vs. 200 pM). The IC25 of budesonide on IL-8 release was higher in nasal mucosa than in nasal polyps (145 pM vs. 4 pM). Nedocromil sodium caused a dose-related inhibitory effect on IL-8 release from nasal mucosa (IC25, 207 nM), while it only had a significant effect in nasal polyps at 10(-5) M. Nedocromil sodium had no effect on IL-6 release. The inhibitory effect of budesonide was higher than that of nedocromil sodium on both nasal polyps and nasal mucosa. Budesonide and nedocromil sodium may exert their anti-inflammatory action in the respiratory mucosa by modulating the secretion of IL-6 and IL-8. The different effect of budesonide and nedocromil sodium on IL-6 and IL-8 release may be explained by differences in the mechanisms which regulate the upregulation of these cytokines in inflammatory responses.

Adolescent↗
PubMed2001

A comparison of three scales for assessing social functioning in primary care.

OBJECTIVE: Assessment of functional status is increasingly important in clinical trials and outcome research. Although several scales for assessing functioning are widely used, they vary in coverage, and direct comparisons among them are rare. Comparative information is useful in guiding selection of appropriate scales for research applications. METHOD: Results from three scales that measure functioning-the Medical Outcomes Study 36-item Short-Form Health Survey, the Social Adjustment Scale Self-Report, and the Social Adaptation Self-Evaluation Scale-were compared in a consecutively selected sample of 211 patients coming to primary care. Patients also received psychiatric assessments. RESULTS: All three scales were acceptable to patients, showed few significant correlations with demographic variables, and were able to differentiate psychiatrically ill and well patients. Correlations among scales, even among scale items that assessed similar domains of functioning, were modest. CONCLUSIONS: Although all three scales are presumed to assess functional status, their item content and coverage differ. Selection of a scale requires a review of the scale items and consideration of research priorities and the characteristics of the study group. If functional status is a critical outcome measure, use of more than one scale may be necessary.

Adult↗
PubMed2001

Freezing protects against allergy to Anisakis simplex.

BACKGROUND: Allergic reactions to Anisakis simplex have been described following ingestion of fish and were thought to be possible even if seafood is frozen or well-cooked. OBJECTIVE: This study aimed to confirm, by challenge test, that dead A. simplex larvae are not able to trigger allergic reactions in patients with proven hypersensitivity to this parasite. METHODS: Simple-blind, placebo-controlled, oral challenge tests with frozen A. simplex larvae were performed in 12 patients who had suffered severe anaphylactic reactions after ingestion of seafood and diagnosed of A. simplex hypersensitivity by skin prick test and specific IgE. If no reaction appeared, they were told to eat frozen seafood. 63 patients who had suffered urticaria or urticaria/angioedema by demonstratred hypersensitivity to A. simplex were also advised to eat frozen seafood. All of them were reevaluated 6 months later. RESULTS: All patients tolerated the dead larvae challenge test. After eating previously frozen seafood at least two times per week, all patients, including those who had suffered anaphylactic reactions and those who had only presented cutaneous manifestations, remained asymptomatic. CONCLUSIONS: Anisakis simplex-allergic patients tolerate ingestion of dead larvae. It is probable that these patients can eat frozen fish and that a seafood-free diet is not necessary.

Adult↗
PubMed2000

Inducible nitric oxide synthase inhibitors suppress airway inflammation in mice through down-regulation of chemokine expression.

Growing evidence demonstrates that inducible NO synthase (iNOS) is induced in the airways of asthmatic patients. However, the precise role of NO in the lung inflammation is unknown. This study investigated the effect of both selective and nonselective iNOS inhibitors in an allergen-driven murine lung inflammation model. OVA challenge resulted in an accumulation of eosinophils and neutrophils in the airways. Expression of iNOS immunostaining in lung sections together with an increase in calcium-independent NOS activity in lung homogenates was also observed after OVA challenge. Treatment with iNOS inhibitors from the day of challenge to the day of sacrifice resulted in an inhibition of the inflammatory cell influx together with a down-regulation of macrophage inflammatory protein-2 and monocyte chemoattractant protein-1 production. In contrast, eosinophilic and neutrophilic inhibition was not observed with treatment during the sensitization. Both treatments induced an increased production of Th2-type cytokines (IL-4 and IL-5) with a concomitant decrease in production of Th1-type cytokine (IFN-gamma). In vitro exposure of primary cultures of murine lung fibroblasts to a NO donor, hydroxylamine, induced a dose-dependent release of macrophage inflammatory protein-2 and monocyte chemoattractant protein-1. Our results suggest that lung inflammation after allergen challenge in mice is partially dependent on NO produced mainly by iNOS. NO appears to increase lung chemokine expression and, thereby, to facilitate influx of inflammatory cells into the airways.

Administration, Intranasal↗
PubMed2000

Long-term hydroxytamoxifen treatment of an MCF-7-derived breast cancer cell line irreversibly inhibits the expression of estrogenic genes through chromatin remodeling.

Antiestrogen resistance is frequently observed in patients after longterm treatment with tamoxifen, a nonsteroidal antiestrogen widely used for endocrine therapy of breast cancer. In vitro studies in resistant cells showed that the expression of natural estrogen-responsive genes is frequently altered. Using MVLN cells, an MCF-7-derived cell model, we previously demonstrated that 4-hydroxytamoxifen (OHT) treatment irreversibly inactivated an estrogen-regulated chimeric luciferase response by a direct effect of the drug and not through a cell selection process (E. Badia et al., Cancer Res., 54: 5860-5866, 1994). In the present study, we present tamoxifen-resistant but still estrogen-dependent clones isolated after long-term treatment of MVLN cells with OHT and show that progesterone receptor (PR) expression was irreversibly decreased in some of these clones, whereas the PRA:PRB ratio of residual PR remained unchanged. The irreversible inactivation of both chimeric luciferase gene and PR gene expression was associated with the disappearance of DNase 1-hypersensitive sites. In the case of the chimeric gene, at least one of these sites was close to the estrogen responsive element. Genomic sequencing analysis of a clone with very low PR content did not reveal any methylation on CpG dinucleotides or any mutation in the PR gene promoter region. In all of the resistant clones tested and independently of their PR content, estrogen receptor expression was only lowered by half and remained functional, whereas pS2 expression was not modified. We also observed that the residual luciferase activity level (1-2%) of the MVLN clones, the luciferase expression of which had been irreversibly inactivated, was raised 4-fold by trichostatin A treatment. We conclude that long-term OHT treatment may modify the chromatin structure and thus could contribute to differentially silencing natural target genes.

Animals↗
PubMed2000

Systematic reviews and meta-analyses on treatment of asthma: critical evaluation.

OBJECTIVE: To evaluate the clinical, methodological, and reporting aspects of systematic reviews and meta-analyses on the treatment of asthma and to compare those published by the Cochrane Collaboration with those published in paper based journals. DESIGN: Analysis of studies identified from Medline, CINAHL, HealthSTAR, EMBASE, Cochrane Library, personal collections, and reference lists. STUDIES: Articles describing a systematic review or a meta-analysis of the treatment of asthma that were published as a full report, in any language or format, in a peer reviewed journal or the Cochrane Library. MAIN OUTCOME MEASURES: General characteristics of studies reviewed and methodological characteristics (sources of articles; language restrictions; format, design, and publication status of studies included; type of data synthesis; and methodological quality). RESULTS: 50 systematic reviews and meta-analyses were included. More than half were published in the past two years. Twelve reviews were published in the Cochrane Library and 38 were published in 22 peer reviewed journals. Forced expiratory volume in one second was the most frequently used outcome, but few reviews evaluated the effect of treatment on costs or patient preferences. Forty reviews were judged to have serious or extensive flaws. All six reviews associated with industry were in this group. Seven of the 10 most rigorous reviews were published in the Cochrane Library. CONCLUSIONS: Most reviews published in peer reviewed journals or funded by industry have serious methodological flaws that limit their value to guide decisions. Cochrane reviews are more rigorous and better reported than those published in peer reviewed journals.

Asthma↗