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Biomedical subjects

M Ferrer

Publications and source records attributed to M Ferrer.

At least 55 records · Page 3Linked to original sources
PubMed2001

Adaptation of the Asthma Quality of Life Questionnaire to a second language preserves its critical properties: the Spanish version.

To test the metric proprieties of the Spanish version of the Juniper Asthma Quality of Life Questionnaire (AQLQ), we studied 116 adult asthmatic patients with a wide range of disease severity (53 patients were recruited from the respiratory outpatient department, 38 from a primary health care centre and 25 were patients admitted into hospital due to acute asthma). The patients were assessed twice, at recruitment and after 2 months. The AQLQ showed a high internal consistency (Cronbach's alpha = 0.78 to 0.96) and a high 2-week reproducibility (ICC = 0.82 to 0.92). Expected significant differences in AQLQ scores were observed according to disease severity as measured by symptoms, medication, use of services and recruitment setting. The cross-sectional and longitudinal correlations between AQLQ and the overall St. George's Respiratory Questionnaire were strong, moderate to strong between AQLQ and dyspnea and weak to moderate between AQLQ and FEV(1). The changes in AQLQ scores were significantly different in patients who either improved or deteriorated from those patients who remained stable (P <.0001 and P <.01, respectively, for the overall AQLQ). We conclude that the Spanish version of the AQLQ is reliable, valid and sensitive to changes.

Activities of Daily Living↗
PubMed2001

The spanish version of the paediatric asthma quality of life questionnaire (PAQLQ): metric characteristics and equivalence with the original version.

UNLABELLED: The Paediatric Asthma Quality of Life Questionnaire (PAQLQ), developed by Juniper et al., assesses the impact of asthma on children's daily life. It contains 23 items, covering three dimensions: symptoms, activities limitation and emotional function. AIMS: To develop an equivalent Spanish version of the PAQLQ, and to assess its measurement characteristics. METHODS: The forward and back-translation method was used for the adaptation. A longitudinal study (assessments at the 1st and 5th weeks), with patients from the emergency and outpatient departments of three Spanish hospitals, was designed to test the properties of the new adapted version. At each visit, a trained interviewer administered the PAQLQ, a Global Index of Change and a General Health Perception scale. The Peak Expiratory Flow Rate (PEFR) was also recorded daily, together with symptoms, during the prior week. RESULTS: Ninety-nine patients (66.7% males, 42.4% suffering an exacerbation, mean age of 11.3 years) with the following types of asthma were evaluated: mild intermittent (31.3%), mild persistent (36.4%), moderate persistent (29.3%) and severe persistent (3%). At the 1st visit, the mean pre-bronchodilator %PEFR was 87.3%. The Cronbach's alpha ranged from 0.86 to 0.95. As expected, correlations between the PAQLQ scores, and the Asthma Control Score (0.53-0.67), the General Health Perception (0.34-0.55), and the %PEFR (0.44-0.55) were moderate. The PAQLQ scores remained unchanged in stable patients while increased significantly in those showing improvements. CONCLUSIONS: After a standard cross-cultural adaptation process, the Spanish version of the PAQLQ has shown to be equivalent to the original, with similar internal consistency reliability, validity and sensitivity to clinical changes.

Adolescent↗
PubMed2001

Microbial investigation in ventilator-associated pneumonia.

Ventilator-associated pneumonia (VAP) is a serious infectious condition in intensive care unit (ICU) patients, currently related to a high mortality rate. Therefore, this complication of mechanical ventilation requires a prompt diagnosis and adequate antibiotic treatment. The detection of the causative organism is imperative for guiding an appropriate therapy as there is strong evidence of the adverse effect of inadequate empirical treatment on outcome. The major difficulty of the microbial investigation is to obtain the sample from the lower respiratory tract, mainly because of the potential contamination with upper airways flora, which may result in a misinterpretation of the cultures. Microbial investigation in VAP is based on the culture of samples obtained from lower respiratory tract by noninvasive or invasive methods. The most common techniques of sampling are the endotracheal aspirate (ETA), which is considered a noninvasive method, the protected specimen brush (PSB) and the bronchoalveolar lavage (BAL), both being invasive methods of investigation. The latter were designed as an attempt to avoid the colonizing flora of the upper airways. The best of these diagnostic approaches is still controversial. In terms of outcome, there is strong evidence that the impact of both invasive and noninvasive methods seems to be similar. In terms of cost, however, the endotracheal aspirate is less expensive compared to BAL or PSB. On the other hand, invasive methods could be particularly beneficial in patients who are not responding to the initial empirical antibiotic treatment. The rationale for the quantitative culture of the respiratory samples is to differentiate between infection and colonization of lower airways, because the bacterial colonization is a frequent event in mechanically ventilated patients. The thresholds currently employed for the diagnosis of the pneumonia are the following: ETA samples, > or = 10(5)-10(6) colony forming units (cfu).mL(-1); PSB samples, > or =10(3) cfu.mL(-1); and BAL samples, > or =10(4) cfu.mL(-1). Intending to provide a practical approach to the issue, the present manuscript reviews the available noninvasive (blood culture, endotracheal aspirate) and invasive (protected specimen brush, bronchoalveolar lavage, blinded methods and lung biopsy) techniques used for the diagnosis of ventilator-associated pneumonia.

Bacteriological Techniques↗
PubMed2001

Aging alters neuronal nitric oxide release from rat mesenteric arteries: role of presynaptic beta-adrenoceptors.

This study examines the influence of aging on the neuronal nitric oxide (NO) and noradrenaline (NA) release elicited by electrical field stimulation (EFS; 200 mA, 0.3 ms, 1-16 Hz, 30 s) in endothelium-denuded mesenteric arteries from young and old rats, as well as the influence of the presynaptic beta-adrenoceptors in that release. EFS induced frequency-dependent contractions. N(G)-nitro-l-arginine methyl ester (l-NAME) only enhanced EFS-elicited contractions in arteries from young rats. Capsaicin did not alter the EFS-induced contractions in either age group. Clenbuterol did not modify the contraction elicited by EFS in arteries from young or old rats either. A subsequent addition of l-NAME also induced an increase in the EFS-induced response in arteries from both age groups. In old rats, the presence of propranolol did not alter the response induced by EFS, and the subsequent addition of clenbuterol or clenbuterol plus l-NAME did not affect this response. In precontracted segments, sodium nitroprusside or clenbuterol induced similar relaxation in both age groups. None of the drugs used altered the response to exogenous NA or basal tone. In arteries preincubated with [(3)H]NA, EFS induced (3)H release, which remained unmodified in the presence of clenbuterol or propranolol in young rats, whereas clenbuterol increased the (3)H overflow in old rats, and this effect was abolished by propranolol. These drugs did not alter the basal (3)H efflux and indicate that in rat mesenteric arteries EFS induces NA release in both age groups, and only NO release in young animals. Activation of presynaptic beta-adrenoceptors increased NA and probably NO release in aged rats.

Adrenergic beta-Agonists↗
PubMed2001

Study of the in vitro sulphidoleukotriene production in food-allergic patients.

OBJECTIVE AND DESIGN: To study in vitro sulphidoleukotriene (sLT) production by food allergic patients using cellular allergen stimulation test (CAST)-ELISA and to evaluate the reliability of this technique for diagnosing food allergic reactions. SUBJECTS: Forty patients with adverse reactions after food intake, 20 healthy controls, and 15 individuals sensitized to inhalant allergens as atopic controls. METHODS: Skin tests, serum-specific IgE, histamine release test (HRT), CAST-ELISA and food challenges. One-way ANOVA was used to compare tests results between patients and controls and to study mediator release and specific IgE, related to the severity of clinical pictures. Sensitivity and specificity were analyzed by ROC curves. RESULTS: Food allergic patients showed higher (p < 0.05) Ag-dependent sLT production (836.2 +/- 664.1 pg/ml) (mean +/- standard deviation) than both control groups. After stimulus with anti-IgE antibodies, sLT production was higher (p < 0.05) by atopic controls (1630.8 +/- 696.5 pg/ml) compared to patients and healthy controls. Patients with anaphylactic reactions showed higher Ag-specific and anti-IgE sLT and histamine production than patients with less severe manifestations. Mean serum-specific IgE was significantly lower (p < 0.05) in patients presenting oral allergy syndrome compared to patients with more severe clinical pictures. CAST-ELISA was the most sensitive method. Prick by prick test was the most specific. CONCLUSIONS: CAST-ELISA may provide a useful tool for diagnosing food allergy. Enhanced cell releasability may be linked to the severity of the clinical response to foods.

Adolescent↗
PubMed2000

Inversion of stereospecificity of vanillyl-alcohol oxidase.

Vanillyl-alcohol oxidase (VAO) is the prototype of a newly recognized family of structurally related oxidoreductases sharing a conserved FAD-binding domain. The active site of VAO is formed by a cavity where the enzyme is able to catalyze many reactions with phenolic substrates. Among these reactions is the stereospecific hydroxylation of 4-ethylphenol-forming (R)-1-(4'-hydroxyphenyl)ethanol. During this conversion, Asp-170 is probably critical for the hydration of the initially formed p-quinone methide intermediate. By site-directed mutagenesis, the putative active site base has been relocated to the opposite face of the active site cavity. In this way, a change in stereospecificity has been achieved. Like native VAO, the single mutants T457E, D170A, and D170S preferentially converted 4-ethylphenol to the (R)-enantiomer of 1-(4'-hydroxyphenyl)ethanol. The double mutants D170A/T457E and D170S/T457E exhibited an inverted stereospecificity with 4-ethylphenol. Particularly, D170S/T457E was strongly (S)-selective, with an enantiomeric excess of 80%. The crystal structure of D170S/T457E, in complex with trifluoromethylphenol, showed a highly conserved mode of ligand binding and revealed that the distinctive catalytic properties of this mutant are not caused by major structural changes.

Alcohol Oxidoreductases↗
PubMed2000

Diabetes alters neuronal nitric oxide release from rat mesenteric arteries. Role of protein kinase C.

The objective of the present study was to assess the influence of diabetes in the neuronal nitric oxide (NO) release elicited by electrical field stimulation (EFS, 200 mA, 0.3 ms, 1-16 Hz, for 30 s, at 1 min interval) in endothelium-denuded mesenteric artery segments from control and streptozotocin-induced diabetic rats, assessing the influence of protein kinase C (PKC) in this release. N(G)-nitro-L-arginine-methyl ester (L-NAME, 10 microM, a NO synthase inhibitor) enhanced EFS-elicited contractions in control, and specially in diabetic rats, whereas they were unaltered by AMT (5 nM, an inducible NO synthase inhibitor) and capsaicin (0.5 microM, a sensory neurone toxin). Calphostin C (0.1 microM, a PKC inhibitor) increased the contraction elicited by EFS in both types of arteries. This increase was further enhanced by calphostin C + L-NAME in diabetic rats. Phorbol 12,13-dibutyrate (PDBu, 1 microM) reduced and unaltered EFS-induced contractions in control and diabetic rats, respectively. The further addition of L-NAME reversed the reduction obtained in control rats, and enhanced the response observed in diabetic rats. These results suggest that the EFS-induced NO release from perivascular nitrergic nerves, that negatively modulates the contraction, which is synthesized by neuronal constitutive NO synthase. The NO synthesis is positively stimulated by PKC. This NO release is increased in diabetes, likely due to an increase in the activity of this enzyme. The sensory nerves of these arteries do not seem to be involved in the contractile response.

Animals↗
PubMed2000

Evolution of self-rated health status in the elderly: cross-sectional vs. longitudinal estimates.

We assessed the perceived health status evolution among elderly subjects and examined the age-related differences in perceived health when comparing estimates obtained from cross-sectional and longitudinal approaches. Data come from a cohort of non-institutionalized individuals aged 65 years or older, living in Barcelona, Spain. One thousand three hundred fifteen (1315) elderly were successfully interviewed at baseline in 1986 and 754 (84.6% of the eligible) at the re-assessment (1993-1994). Estimates of change in perceived health status were calculated based on cross-sectional and longitudinal approaches. Cross-sectionally, no significant differences in the proportion of individuals with poor self-rated health were found (40.5 vs. 42.5%, P = 0.90). Among survivors, the proportion of individuals with poor health increased from 37.8% to 55.1% (P < 0.01), an 8.7-fold decline of perceived health when compared with the cross-sectional estimates. Comorbidity (aOR 2.1; 95%CI: 1.4-3.3) and no education (aOR 1.9; 95%CI: 1.1-3.2) were associated with a decline in health status after adjusting by baseline health status. We recommend the use of longitudinal studies to understand the evolution of perceived health in the elderly.

Aged↗
PubMed2000

The structure of an HIV-1 specific cell entry inhibitor in complex with the HIV-1 gp41 trimeric core.

The three-dimensional structure of the complex between an HIV-1 cell-entry inhibitor selected from screening a combinatorial library of non-natural building blocks and the central, trimeric, coiled-coil core of HIV-1 gp41 has been determined by X-ray crystallography. The biased combinatorial library was designed to identify ligands binding in nonpolar pockets on the surface of the coiled-coil core of gp41. The crystal structure shows that the non-peptide moiety of the inhibitor binds to the targeted cavity in two different binding modes. This result suggests a strategy for increasing inhibitor potency by use of a second-generation combinatorial library designed to give simultaneous occupancy of both binding sites.

Anti-HIV Agents↗
PubMed2000

Noninvasive assessment of respiratory resistance in severe chronic respiratory patients with nasal CPAP.

Noninvasive measurement of respiratory resistance during nasal ventilatory support could be useful to assess the mechanical status of the patient and to optimize the ventilator settings. The aim was to investigate whether the forced oscillation technique (FOT) applied through a nasal mask allows reliable noninvasive estimation of respiratory resistance (Rrs) in patients with severe chronic respiratory disease. FOT Rrs (5 Hz) and lung resistance (R(L)) measured simultaneously from spontaneous breathing signals by an oesophageal balloon were compared in eight patients with chronic obstructive pulmonary disease and in six patients with a restrictive ventilatory defect due to chest wall disease. Measurements were performed in sitting and supine postures during application of nasal continuous positive airway pressure (CPAP): 4, 8 and 12 cmH2O in obstructive patients and 4 cmH2O in restrictive patients. In the restrictive patients Rrs and R(L) (in cmH2O x s x L(-1)) were virtually coincident: mean+/-SD, 12.6+/-6.1 and 11.6+/-6.6 (r=0.96) in sitting and 9.7+/-3.1 and 10.2+/-3.3 (r=0.92) in supine posture, respectively. In the obstructive patients (CPAP = 4 cmH2O), Rrs slightly underestimated R(L): mean+/-SD, 11.5+/-5.9 and 14.4+/-16.8 (r=0.92) in sitting and 15.0+/-9.8 and 21.1+/-12.6 (r=0.96) in supine posture, respectively. Similar results were found at CPAP = 8 and 12 cmH2O. The results obtained in patients with resistance values in the range typically found in nasal ventilatory support suggest that forced oscillation technique could be valuable to noninvasively estimate a patient's respiratory mechanical resistance.

Aged↗
PubMed2000

Increase in neurogenic nitric oxide metabolism by endothelin-1 in mesenteric arteries from hypertensive rats.

We investigated, in mesenteric arteries from hypertensive rats (SHRs), the possible changes in neurogenic nitric oxide (NO) release produced by endothelin-1 (ET-1), and the mechanisms involved in this process. The contractile response induced by electrical field stimulation (EFS; 200 mA, 0.3 ms, 1-16 Hz, for 30 s) in deendotheliumized mesenteric segments was abolished by tetrodotoxin and phentolamine. The NO synthase inhibitor N(G)-nitro-L-arginine (L-NAME, 10 microM) increased the contractions caused by EFS. ET-1 enhanced the contraction induced by EFS, which was unaltered by the subsequent addition of L-NAME. The ETA antagonist-receptor BQ-123 (1 microM) inhibited the effect of ET-1 on EFS response, whereas the ETB antagonist-receptor BQ-788 (3 microM) partially blocked it, and the subsequent addition of L-NAME restored the contractile response in both cases. SOD (25 unit/ml) decreased the response to EFS, and the subsequent addition of L-NAME increased this response. ET-1 did not modify the decrease in EFS response induced by SOD, and the addition of L-NAME increased the response. None of these drugs altered the response to exogenous noradrenaline (NA) or basal tone except SOD, which increased the basal tone, an effect blocked by phentolamine (1 microM). In arteries preincubated with [3H]NA, ET-1 did not modify the tritium efflux evoked by EFS, which was diminished by SOD. ET-1 did not alter basal tritium efflux, whereas SOD significantly increased the efflux. These results suggest that EFS of SHR mesenteric arteries releases neurogenic NO, the metabolism of which is increased in the presence of ET-1 by the generation of superoxide anions.

Analysis of Variance↗
PubMed2000

Quality of life and economic features in elderly asthmatics.

BACKGROUND: In the geriatric population, asthma tends to be overlooked. Moreover, typical symptoms of asthma may mimic chronic bronchitis and emphysema. OBJECTIVE: To compare the characteristics of asthma between elderly (>/=65 years) and adult (<65 years) asthma patients with regard to asthma severity, health-related quality of life, and direct expenditures for medical care generated by the disease. METHODS: A cross-sectional study was made in the asthmatic population older than 14 years in the area of Barcelona, Spain. Asthma severity was determined according to the International Consensus criteria of 1992. St. George's Respiratory Questionnaire (SGRQ) was used to measure the quality of life. Direct costs were calculated registering all costs generated by each patient per year. RESULTS: The study population consisted of 282 adult asthmatics and 51 elderly asthmatics. Asthma was more severe in the elderly group (mild 10%, moderate 35%, severe 55%) than in the adult group (mild 47%, moderate 35%, severe 18%). Elderly asthmatics had significantly higher total SGRQ scores (48 vs. 35, p < 0.001) than adult asthmatics, as well as significantly higher scores for all subscales. Asthma-derived direct costs in elderly asthmatics (mean USD 1,490 vs. USD 773) were double those in adult asthmatics, mainly due to higher costs of hospitalization and medication in the elderly. CONCLUSIONS: Asthma in elderly people as compared with asthma in adulthood was more severe and was associated with a worse health-related quality of life, and significantly higher expenditures for medical care.

Aged↗
PubMed2000

Pulmonary gas exchange response to oxygen breathing in acute lung injury.

The mechanisms and time course of the pulmonary gas exchange response to 100% O(2) breathing in acute respiratory failure needing mechanical ventilation were studied in eight patients with acute lung injury (ALI) (48 +/- 18 yr [mean +/- SD]) and in four patients (66 +/- 2 yr) with chronic obstructive pulmonary disease (COPD). We postulated that, in patients with ALI while breathing 100% O(2), the primary mechanism of hypoxemia, i.e., increased intrapulmonary shunt, would further worsen (increase) as a result of reabsorption atelectasis. Respiratory and inert gases, and systemic and pulmonary hemodynamics were measured at maintenance fraction of inspired oxygen (FI(O(2))-m), at 30 and 60 min while breathing 100% O(2), and then at 30 min of resuming FI(O(2))-m. During 100% O(2) breathing, in patients with ALI, Pa(O(2)) (by 207 and 204 mm Hg; p < 0.01 each), Pa(CO(2)) (by 4 mm Hg each) (p < 0.05 each), and intrapulmonary shunt (from 16 +/- 10% to 22 +/- 11% and 23 +/- 11%) (p < 0.05 each) increased respectively. By contrast, in patients with COPD, Pa(O(2)) (by 387 and 393 mm Hg; p < 0.001 each), Pa(CO(2)) (by 4 and 5 mm Hg) and the dispersion of pulmonary blood flow (log SDQ) (from 1.33 +/- 0.10 to 1.60 +/- 0.20 and 1.80 +/- 0.30 [p < 0.05]) increased, respectively. In patients with ALI, the breathing of 100% O(2) deteriorates intrapulmonary shunt owing to collapse of unstable alveolar units with very low ventilation-perfusion (V A/Q) ratios, as opposed to patients with COPD, in whom only the dispersion of the blood flow distribution is disturbed, suggesting release of hypoxic pulmonary vasoconstriction.

Aged↗
PubMed2000

Capnometric recirculation gas tonometry and weaning from mechanical ventilation.

The aim of this study was to describe changes in regional intramucosal PCO(2) (Pr(CO(2)) measured with capnometric recirculation gas tonometry [CRGT]) in patients with acute respiratory failure, who proceed from mechanical ventilation to weaning. In addition, we compared the predictive power for the weaning outcome of CRGT measurements obtained during mechanical ventilation to the frequency/ tidal volume (f/VT) ratio. A total of 24 patients (31 weaning trials) were included in the study, but four of the 24 patients (17%) were excluded because of extubation failure. Of the remaining 27 weaning trials in 20 patients, 12 (44%) were unsuccessful. Changes observed in patients with weaning failure (increase in Pr(CO(2)) from 60.4 +/- 15.0 mm Hg in mechanical ventilation to 67.4 +/- 21.0 mm Hg, in weaning) were significantly different (p = 0.046) from those observed in patients with weaning success (fall in Pr(CO(2)) from 61.5 +/- 15.0 mm Hg in mechanical ventilation to 56.3 +/- 16.7 mm Hg in weaning). However, absolute values of Pr(CO(2)) were not significantly different between patients with weaning success and failure, neither during mechanical ventilation (success, 61.5 +/- 15.0 versus failure, 60.4 +/- 15.0 mm Hg, p = 0.848) nor during weaning (success, 56.3 +/- 16.7 versus failure, 67.4 +/- 21.0 mm Hg, p = 0.135). The best single predictor for weaning outcome was the f/VT ratio measured early during weaning (area under the curve: 0.844 +/- 0.081; adjusted odds ratio for threshold value </= 105: 42.0, 95% CI 3.8 to 469.1, p = 0.002). CRGT could confirm a significant increase in Pr(CO(2)) during weaning in patients who finally failed the weaning trial. However, differences between patients with weaning success and failure were small and CRGT did not replace or improve the predictive power of the f/VT ratio for weaning outcome.

Acute Disease↗
PubMed2000

Role of protein kinase C in electrical-stimulation-induced neuronal nitric oxide release in mesenteric arteries from hypertensive rats.

This study examines the influence of hypertension on neuronal nitric oxide (NO) release and its modulation by protein kinase C (PKC). For this purpose, mesenteric segments without endothelium were obtained from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs), and neurogenic NO release induced by electrical field stimulation (EFS) was examined in these segments. EFS induced frequency-dependent contractions. The NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) and the sensorial neurotoxin capsaicin increased EFS-induced contractions in SHR segments, but did not affect these contractions in segments from WKY rats. In segments from SHRs, the increase in EFS-induced response by capsaicin was further increased by the combination of capsaicin and L-NAME. EFS-induced contractions in SHR arteries were unaltered by the protein synthesis inhibitor cycloheximide or by 2-amine-5,6-dihydro-6-methyl-4H-1,3-tiazine (AMT), an inhibitor of inducible NO synthase, and increased by the guanylate cyclase inhibitor Methylene Blue. In these arteries, capsaicin plus the PKC inhibitor calphostin C increased the contractions elicited by EFS; the addition of L-NAME did not affect this increase. Phorbol 12,13-dibutyrate (PDBu) did not modify the response to EFS in these arteries pretreated with capsaicin, although a combination of PDBu and L-NAME was effective. These results indicate that, in mesenteric arteries, EFS induces the release of NO from perivascular nitrergic nerves and of neuropeptides from sensory nerves, but only in hypertensive rats. The NO released is synthesized by constitutive neuronal NO synthase in a manner that is positively modulated by PKC, an enzyme that seems to be activated in hypertension.

Animals↗
PubMed1999

The mine tailing accident in Aznalcollar.

Massive amounts of acidic waters and mud (pH approximately 3) containing toxic metals such as zinc, lead, arsenic, copper, antimony, cobalt, thallium, bismuth, cadmium, silver, mercury and selenium were released in the surroundings of Doñana Park as a consequence of the mine tailings spill accident in Aznalcollar (SW Spain). This introductory paper describes the main characteristics of Doñana Park, the mine activities developed in Aznalcollar and their related environmental risks. The tailing spill accident and the first package of urgent actions undertaken for preventive and mitigation purposes are also summarized.

Accidents, Occupational↗