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Biomedical subjects

R Farré

Publications and source records attributed to R Farré.

At least 19 recordsLinked to original sources
PubMed2006

The effect of bolus viscosity on swallowing function in neurogenic dysphagia.

AIM: To assess the pathophysiology and treatment of neurogenic dysphagia. METHODS: 46 patients with brain damage, 46 with neurodegenerative diseases and eight healthy volunteers were studied by videofluoroscopy while swallowing 3-20 mL liquid (20.4 mPa s), nectar (274.4 mPa s) and pudding (3931.2 mPa s) boluses. RESULTS: Volunteers presented a safe and efficacious swallow, short swallow response (< or =740 ms), fast laryngeal closure (< or =160 ms) and strong bolus propulsion (> or =0.33 mJ). Brain damage patients presented: (i) 21.6% aspiration of liquids, reduced by nectar (10.5%) and pudding (5.3%) viscosity (P < 0.05) and (ii) 39.5% oropharyngeal residue. Neurodegenerative patients presented: (i) 16.2% aspiration of liquids, reduced by nectar (8.3%) and pudding (2.9%) viscosity (P < 0.05) and (ii) 44.4% oropharyngeal residue. Both group of patients presented prolonged swallow response (> or =806 ms) with a delay in laryngeal closure (> or =245 ms), and weak bolus propulsion forces (< or =0.20 mJ). Increasing viscosity did not affect timing of swallow response or bolus kinetic energy. CONCLUSIONS: Patients with neurogenic dysphagia presented high prevalence of videofluoroscopic signs of impaired safety and efficacy of swallow, and were at high risk of respiratory and nutritional complications. Impaired safety is associated with slow oropharyngeal reconfiguration and impaired efficacy with low bolus propulsion. Increasing bolus viscosity greatly improves swallowing function in neurological patients.

Adult↗
PubMed2006

Analysis of phytosterols in foods.

Phytosterols are bioactive compounds, one of their most studied and outstanding properties being their cholesterol-lowering activity. This explains the growing interest in the phytosterol contents of foods as either intrinsic or added components. The different steps (extraction, saponification, clean up, chromatographic determination) of plant sterol determination are reviewed, and emphasis is placed on the methods used to assay different phytosterols in food.

Animals↗
PubMed2006

Absence of veno-occlussive disease in a cohort of multiple myeloma patients undergoing autologous stem cell transplantation with targeted busulfan dosage.

BACKGROUND: Plasma concentrations of oral busulfan (BU) were measured in multiple myeloma (MM) patients undergoing autologous peripheral blood stem cell transplantation (ASCT) with a double alkylating conditioning protocol in order to individualise doses of BU based on individual pharmacokinetic parameters and to reduce toxicities related to BU exposure. PATIENTS AND METHODS: Forty-four consecutive patients with MM participating in the co-operative Spanish protocol were prospectively evaluated. Conditioning regimen prior to autologous infusion consisted of BU followed by melphalan. BU pharmacokinetic parameters were estimated for each patient after the first dose based on measured concentrations and subsequent doses were modified as necessary to achieve target exposure. RESULTS: Mean BU exposure (AUCss) (+/-DS) before dosage modification range from 3192 to 12 180 ng h/mL. Twenty-six out of 44 (59%) patients required dose adjustment. None of the patients developed hepatic veno-occlusive disease (VOD). Grade > or = II oropharyngeal mucositis was observed in the majority of patients (95%) and the severity of mucositis increased with increasing average steady-state BU plasma concentration. There were four treatment-related deaths: two patients died from multiorgan failure and two of respiratory infections. Of the remaining 40 patients, 15 were in complete remission with negative immunofixation, 21 in partial remission and four in stable disease 3 months after ASCT. CONCLUSIONS: The results of the present study show the variability in BU pharmacokinetic parameters and suggest the possible relationship between toxicities and BU exposure. Individualising BU dosage in MM patients undergoing ASCT we observed the absence of VOD.

Adult↗
PubMed2006

Performance of mechanical ventilators at the patient's home: a multicentre quality control study.

BACKGROUND: Quality control procedures vary considerably among the providers of equipment for home mechanical ventilation (HMV). METHODS: A multicentre quality control survey of HMV was performed at the home of 300 patients included in the HMV programmes of four hospitals in Barcelona. It consisted of three steps: (1) the prescribed ventilation settings, the actual settings in the ventilator control panel, and the actual performance of the ventilator measured at home were compared; (2) the different ventilator alarms were tested; and (3) the effect of differences between the prescribed settings and the actual performance of the ventilator on non-programmed readmissions of the patient was determined. RESULTS: Considerable differences were found between actual, set, and prescribed values of ventilator variables; these differences were similar in volume and pressure preset ventilators. The percentage of patients with a discrepancy between the prescribed and actual measured main ventilator variable (minute ventilation or inspiratory pressure) of more than 20% and 30% was 13% and 4%, respectively. The number of ventilators with built in alarms for power off, disconnection, or obstruction was 225, 280 and 157, respectively. These alarms did not work in two (0.9%), 52 (18.6%) and eight (5.1%) ventilators, respectively. The number of non-programmed hospital readmissions in the year before the study did not correlate with the index of ventilator error. CONCLUSIONS: This study illustrates the current limitations of the quality control of HMV and suggests that improvements should be made to ensure adequate ventilator settings and correct ventilator performance and ventilator alarm operation.

Analysis of Variance↗
PubMed2006

Noninvasive detection of expiratory flow limitation in COPD patients during nasal CPAP.

The difference between mean inspiratory and expiratory respiratory reactance (delta(rs)) measured with forced oscillation technique (FOT) at 5 Hz allows the detection of expiratory flow limitation (EFL) in chronic obstructive pulmonary disease (COPD) patients breathing spontaneously. This aim of this study was to evaluate whether this approach can be applied to COPD patients during noninvasive pressure support. Delta(rs) was measured in seven COPD patients subjected to nasal continuous positive airway pressure (CPAP) at 0, 4, 8 and 12 cmH2O in sitting and supine positions. Simultaneous recording of oesophageal pressure and the Mead and Whittenberger (M-W) method provided a reference for scoring each breath as flow-limited (FL), non-flow-limited (NFL) or indeterminate (I). For each patient, six consecutive breaths were analysed for each posture and CPAP level. According to M-W scoring, 47 breaths were FL, 166 NFL and 51 I. EFL scoring using FOT coincided with M-W in 94.8% of the breaths. In the four patients who were FL in at least one condition, delta(rs) was reduced with increasing CPAP. These data suggest that the forced oscillation technique may be useful in chronic obstructive pulmonary disease patients on nasal pressure support by identifying continuous positive airway pressure levels that support breathing without increasing lung volume, which in turn increase the work of breathing and reduce muscle effectiveness and efficiency.

Aged↗
PubMed2004

Gas chromatographic determination of organochlorine pesticides in cow milk.

A gas chromatographic method of use in determining the following organochlorine pesticides in cow milk has been adapted and validated: alpha-hexachlorocyclohexane (alpha-HCH), beta-HCH, lindane, delta-HCH, hexachlorobenzene, aldrin, heptachlor, heptachlor epoxide, mirex, 2,4-dichlorodiphenyltrichloroethane (2,4-DDT), 4,4-DDT, 2,4-dichlorodiphenyldichloroethane (2,4-DDD), 4,4-DDD, 2,4-dichlorodiphenylethane (2,4-DDE) and 4,4-DDE. The method studied consists of three steps: the extraction of fat by centrifugation, mixing with anhydrous sodium sulfate, and transfer to a glass column and elution with hexane; purification of the extract via concentrated sulfuric acid treatment; and determination of the organochlorine pesticides by gas chromatography equipped with an electron capture detector. The analytical parameters determined to estimate the quality of the method yielded the following results: correlation coefficients (r) of the calibration curves were greater than 0.996, the variation coefficients of the response factors were less than 4.90%--with the exception of aldrin (5.53%) and lindane (5.75%)--the relative standard deviation of the slope (Sm rel) being < or =1.52%. Zero was included in the confidence limits of the independent term range. The method repeatability and reproducibility values were < or =4.73% and < or =5.79%, respectively. The recovery values of the pesticides analyzed were in the range of 81.92% (alpha-HCH) to 105.49% (4,4-DDT), except in the case of aldrin and heptachlor epoxide, which yielded recovery values of under 40%. The quantification limits of the method were < or =1 ng/g, with the exception of mirex (5 ng/g).

Animals↗
PubMed2004

Noninvasive monitoring of respiratory mechanics during sleep.

The sleep apnoea-hypopnoea syndrome is characterised by recurrent obstructions of the upper airway, resulting in sleep disruption and arterial oxygen desaturations. Noninvasive assessment of respiratory mechanics during sleep is helpful in facilitating the diagnosis and treatment of patients with sleep apnoea-hypopnoea syndrome. This series summarises the different tools that are currently available to noninvasively assess respiratory mechanics during sleep breathing disturbances. These techniques are classified according to the main variable monitored: ventilation, breathing effort or airway obstruction. Changes in patient ventilation are assessed by recording flow or volume signals by means of pneumotachographs, thermistors or thermocouples, nasal prongs or thoraco-abdominal bands. Common tools to noninvasively assess breathing efforts are the thoraco-abdominal bands and the pulse transit time technique. Upper airway obstruction is noninvasively characterised by its upstream resistance and its critical pressure or by means of the forced oscillation technique. Given the technical and practical limitations of each technique, combining different tools improves the reliability and robustness of patient assessment during sleep.

Humans↗
PubMed2003

Estimation of arsenic bioaccessibility in edible seaweed by an in vitro digestion method.

The aim of this study was to examine the bioaccessibility (maximum soluble concentration in gastrointestinal medium) of total (AsT) and inorganic (AsI) arsenic contents and the effect on them of cooking edible seaweed, a food of great interest because of its high As content. An in vitro gastrointestinal digestion (pepsin, pH 2, and pancreatin-bile extract, pH 7) was applied to obtain the mineral soluble fraction of three seaweeds (Hizikia fusiforme, Porphyra sp., and Enteromorpha sp.). AsT was determined by dry-ashing flow injection hydride generation atomic absorption spectrometry. AsI was determined by acid digestion, solvent extraction, and flow injection hydride generation atomic absorption spectrometry. The bioaccessibility of AsI increased significantly after cooking, attaining 73% in Porphyra sp. and 88% in H. fusiforme. For cooked H. fusiforme, the AsI attained in the bioaccessible fraction was 26 microg g(-1) seaweed, a concentration that is a warning of the toxicological risk of this food.

Arsenic↗
PubMed2003

[Protocol to evaluate automatic continuous positive airway pressure. Assessment of the usefulness of the Autoset-T device to determine optimal pressure for treating sleep apnea/hypopnea syndrome].

INTRODUCTION: Given the high prevalence of sleep apnea/hypopnea syndrome (SAHS) and great demand for conventional polysomnography (PSG) and long waiting lists, alternative means for diagnosing SAHS and titrating continuous positive airway pressure (CPAP) are needed. Automatic CPAP may play a role in meeting the last objective, not only for treatment but also for suggesting the optimum CPAP setting. OBJECTIVES: a) To define a protocol to assess the functioning of an automatic CPAP device by means of a mechanical model; b) to determine the behavior of automatically adjusted CPAP during PSG; c) to define the usefulness of automatic CPAP for indicating optimal CPAP pressure for patients with SAHS; d) to evaluate the efficacy of the automatically indicated pressure setting against conventional PSG. METHODS: Four protocols were carried out using the Autoset-T (AT) device. 1. Apneas, hypopneas, flow limitation, snoring and normal flow were simulated in a laboratory using a mechanical model in order to check AT functioning. 2. The behavior of the automatically adjusted CPAP was observed in real time during PSG in 12 patients with severe SAHS. 3. The agreement of CPAP titrated with the AT and with PSG was checked in a group of 39 patients with SAHS. 4. The efficacy of the CPAP pressure recommended by the AT was checked by PSG in a group of 14 patients with SAHS. RESULTS: With the AT, CPAP increased rapidly in response to apneas or snoring in the mechanical model and during conventional PSG; it took only a mean 2.8 3.1 min to rise from a baseline pressure of 4 cm H2O to a near-optimum pressure of 11 1 cm H2O. Once normal flow was reached CPAP slowly decreased, responding with great sensitivity to the slightest abnormality, especially snoring, but not changing in response to certain types of flow limitation. The pressure read visually on the AT was similar to the one recommended by PSG in most of the 39 patients (71%). The PSG performed after one month of using AT-recommended CPAP titration confirmed that the number of apneas, hypopneas (apnea/hypopnea index 6(1) and arousals (8 2) was normal for these SAHS patients. CONCLUSIONS: The AT increases pressure rapidly in the presence of respiratory events and maintains a normal breathing pattern in most patients. Visual reading of the AT pressure allows correct identification of the optimal CPAP setting for SAHS treatment.

Aged↗
PubMed2003

Unsupervised self-testing of airway obstruction by forced oscillation at the patient's home.

As active patient cooperation is not required, the forced oscillation technique (FOT) could be suitable for measuring airway obstruction in routine home applications. Nevertheless, FOT has never been used at the patient's home to date. The aim of this study was to assess the feasibility of FOT and the reproducibility of measured respiratory resistance (Rrs) in routine patient self-testing at home. Altogether, nine asthmatic patients self-measured their Rrs with a portable FOT device and spirometry for 10-14 days, in the morning and evening, and before and after bronchodilator inhalation. During each measurement session, the patients carried out four consecutive FOT measurements. Grubbs' discordancy test for detecting outliers was used to evaluate intermeasure reliability. Only 4.9% of Rrs data reported by patients were rejected as artefacts. The coefficient of variation of Rrs was 7.9 +/- 6.3% (mean +/- SD). When compared with spirometry, the per cent change in Rrs for detecting a positive bronchodilator response showed an 83% sensitivity and 72% specificity. Unsupervised self-measurement of respiratory resistance at the patient's home provided results similar to those obtained by a technician in a lung function lab. Forced oscillation technique could be a useful tool for the routine follow-up of asthmatic patients at home.

Adult↗
PubMed2003

The forced oscillation technique in clinical practice: methodology, recommendations and future developments.

The forced oscillation technique (FOT) is a noninvasive method with which to measure respiratory mechanics. FOT employs small-amplitude pressure oscillations superimposed on the normal breathing and therefore has the advantage over conventional lung function techniques that it does not require the performance of respiratory manoeuvres. The present European Respiratory Society Task Force Report describes the basic principle of the technique and gives guidelines for the application and interpretation of FOT as a routine lung function test in the clinical setting, for both adult and paediatric populations. FOT data, especially those measured at the lower frequencies, are sensitive to airway obstruction, but do not discriminate between obstructive and restrictive lung disorders. There is no consensus regarding the sensitivity of FOT for bronchodilation testing in adults. Values of respiratory resistance have proved sensitive to bronchodilation in children, although the reported cutoff levels remain to be confirmed in future studies. Forced oscillation technique is a reliable method in the assessment of bronchial hyperresponsiveness in adults and children. Moreover, in contrast with spirometry where a deep inspiration is needed, forced oscillation technique does not modify the airway smooth muscle tone. Forced oscillation technique has been shown to be as sensitive as spirometry in detecting impairments of lung function due to smoking or exposure to occupational hazards. Together with the minimal requirement for the subject's cooperation, this makes forced oscillation technique an ideal lung function test for epidemiological and field studies. Novel applications of forced oscillation technique in the clinical setting include the monitoring of respiratory mechanics during mechanical ventilation and sleep.

Adolescent↗
PubMed2002

Determination of liposoluble vitamins in cooked meals, milk and milk products by liquid chromatography.

A method for the simultaneous determination of liposoluble vitamins in cooked meals was established. Saponification was performed with 50% (w/v) KOH at 80 degrees C, and ascorbic acid was added as antioxidant. The subsequent extraction was carried out with diethyl ether. This was followed by a liquid chromatographic separation on a reversed-phase C18 column with methanol-water (94:6, v/v as the mobile phase. Retinyl acetate was used as the internal standard. The analytical parameters linearity, detection limit (0.19 and 8.33 microg/100 g for retinol and alpha-tocopherol, respectively), precision of the method (RSD=5.24 and 6.99% for retinol and alpha-tocopherol, respectively) and recovery assays (95.6 and 96.5% for retinol and alpha-tocopherol, respectively) show that the method studied is useful for measuring these compounds in foods and cooked meals.

Animals↗
PubMed2002

High-performance liquid chromatographic determination of furfural compounds in infant formulas. Changes during heat treatment and storage.

Furfural contents in adapted and follow-up infant formulas were measured by RP-HPLC. The evolution of furfural compound contents during storage (a year at 20 and 37 degrees C) was studied. 2-Furylmethylketone and 5-methyl-2-furaldehyde were not detectable in analysed samples. The differences in the furfural compounds at point zero between both infant formulas has to be ascribed to the differences in protein and iron contents. An increase in free 5-hydroxymethyl-2-furfuraldehyde (HMF), 2-furaldehyde (F) and HMF+F contents was observed in all samples, although the differences were not statistically significant. The storage temperature affected the total HMF content and the storage time affected the total HMF and F contents.

Chromatography, High Pressure Liquid↗
PubMed2002

High-performance liquid chromatographic determination of tocopherols in infant formulas.

A method for the simultaneous determination of alpha-tocopherol acetate and alpha-, delta-, and gamma-tocopherols by normal-phase high-performance liquid chromatography (HPLC) with a fluorescent detector in infant formula is proposed. The values obtained in the determination of the analytical parameters: linearity, precision, limit of detection and accuracy (analysis of a standard reference material, SRM 1846), confirm the quality of the method. The proposed method is useful for the determination of alpha-, delta-, and gamma-tocopherols and alpha-tocopherol acetate in infant formulas at a low cost and in a total time of 2 h.

Chromatography, High Pressure Liquid↗
PubMed2002

Effect of traditional, microwave and industrial cooking on inositol phosphate content in beans, chickpeas and lentils.

An high-performance liquid chromatography method for determining inositol phosphate fractions was adapted to legumes. The validity of the method was assessed by estimating the following analytical parameters: linearity (linear response between 125 and 5000 microg inositol hexaphosphate (IP(6))/ml); instrumental precision and method precision (relative standard deviation, %) were 1.9% (IP(6)) for instrumental, and 2.5% (IP(6)) and 8.2% (IP(5)) for method precision. An accuracy was estimated by percentage recovery (72 +/- 3%). The application of this method to raw, conventional, microwave-cooked and ready-to-eat beans, chickpeas and lentils gave IP(6) contents ranging from 0.63 g/100 g dry matter in ready-to-eat lentils to 1.87 g/100 g dry matter in raw beans. The IP(6) content was reduced by all the cooking procedures, while the relative percentage of inositol pentaphosphate increased in all the legumes studied, and reached the maximum of 31% (expressed in relation to dry matter) in ready-to-eat beans.

Chromatography, High Pressure Liquid↗
PubMed2002

A portable forced oscillation device for respiratory home monitoring.

The increase in the prevalence of chronic respiratory diseases has resulted in a rise in health services provided at home. The forced oscillation technique (FOT) proves to be a useful tool when it is desired to assess lung function noninvasively, and particularly for patients in whom spirometry cannot be applied. As no portable FOT device is currently available, the aim of this study was to design and test a portable FOT system for ambulatory and home care applications. The system devised is based on a microprocessor, which allows online computation of respiratory resistance (Rrs) and reactance (Xrs) and reliability indices. The portable device was compared with a conventional FOT system by using signals from 14 patients with chronic respiratory disease. This device has the same computation capabilities and flexibility as conventional FOT systems and meets the requirements for home application. Rrs (14.2 +/- 6.0 cmH2O x s x L(-1), mean +/- SD) and Xrs (-5.3 +/- 2.7 cmH2O x s x L(-1)) measured at 5 Hz by the portable system virtually coincided with those computed with the reference conventional FOT system: mean differences +/-SD were 0.074 +/- 0.025 and 0.005 +/- 0.009 cmH2O x s x L(-1), respectively. This portable forced oscillation technique device could be a useful tool for monitoring respiratory mechanics in ambulatory and home care applications.

Airway Resistance↗