PubMed Health⌕ Search

Biomedical subjects

M Riu

Publications and source records attributed to M Riu.

11 recordsLinked to original sources
PubMed2006

Comparative study of two chromatographic methods for quantifying 2,4,6-trichloranisole in wines.

Here we present the validation and the comparative study of two chromatographic methods for quantifying 2,4,6-trichloroanisole (TCA) in wines (red, rosé and white wines). The first method involves headspace solid-phase microextraction and gas chromatography with electron-capture detection (ECD). The evaluation of the performance parameters shows limit of detection of 0.3 ng l(-1), limit of quantification of 1.0 ng l(-1), recoveries around 100% and repeatability of 10%. The second one implies a headspace solid-phase microextraction and gas chromatography with mass spectrometric detection. The performance parameters of this second method are limit of detection of 0.2 ng l(-1), limit of quantification of 0.8 ng l(-1) and repeatability of 10.1%. From the comparative study we can state that both methods provide similar results and the differences between them are the better sensitivity of the GC-ECD method and the very shorter chromatogram running time of the GC-MS method. The two methods are able to quantify TCA below the sensorial threshold in red, rosé and white wines using just a calibration graph, thus they could be a very good tool for quality control in wineries.

Anisoles↗
PubMed2006

Quantification of chloroanisoles in cork using headspace solid-phase microextraction and gas chromatography with electron capture detection.

Chloroanisoles can migrate from the cork stopper in wine bottles to the wine and give it a musty taint so it is important to find a method by which they can be determined. The aim of this paper is to develop a method for quantifying 2,4-dichloroanisole, 2,6-dichloroanisole, 2,4,6-trichloroanisole, 2,3,4,6-tetrachloroanisole and 2,3,4,5,6-pentachloroanisole in cork using headspace solid-phase microextraction and gas chromatography with electron capture detection. After we had prepared the cork standards that were so essential to the work we optimised the parameters that most influence headspace solid-phase microextraction: fibre coating, vial volume, cork, kind and volume of solvent to help the extraction, extraction temperature and time, ionic strength and stirring. The method quantifies the total amount of chloroanisoles in cork stoppers (natural, agglomerated, agglomerated with disks and sparkling wine stoppers), at suitable concentrations so that the capacity of these compounds to give wine a musty taint can be evaluated. The quantification limits are: 2,6-dichloroanisole (8.6 ng/g), 2,4,6-trichloroanisole (0.8 ng/g), 2,4-dichloroanisole (3.5 ng/g), 2,3,4,6-tetrachloroanisole (0.6 ng/g), 2,3,4,5,6-pentachloroanisole (0.8 ng/g). The other quality parameters are: recoveries (90.3-105.8%), repeatability (4-13% (RSD expressed)) and intermediate precision (5-14% (RSD expressed)).

Anisoles↗
PubMed2003

Fast screening method for determining 2,4,6-trichloroanisole in wines using a headspace-mass spectrometry (HS-MS) system and multivariate calibration.

The system based on coupling a headspace sampler to a mass spectrometer (HS-MS), which is considered one kind of electronic nose, is an emergent technique for ensuring and controlling quality in industry. It involves injecting the headspace of the sample into the ionization chamber of the mass spectrometer where the analytes are fragmented. The result is a complex mass spectrum for each sample analyzed. When several samples are analyzed the data matrix generated is processed with chemometric techniques to compare and classify the substances from their volatile composition, in other words, to compare and classify their flavor. So far, information from electronic nose applications has mainly been qualitative. In this paper we present a quantitative study that uses a multivariate calibration. We analyzed several white wines using HS-MS to determine 2,4,6-tricholoranisole (TCA). This is an off-flavor that is a serious problem for the wine industry. The method is simple because it does not require sample preparation, only addition of sodium chloride being necessary for sample conditioning. Also, it provides a fast screening (10 min/sample) of the quantity of TCA in wines at ultratrace (sub microg L(-1)) levels.

Anisoles↗
PubMed2002

Determination of 2,4,6-trichloroanisole in wines by headspace solid-phase microextraction and gas chromatography-electron-capture detection.

One of the most important problems in the wine world, today, is cork taint, which often has been chemically identified as 2,4,6-trichloroanisole (TCA). The perception limit of this compound is very low (close to 10 and 40 ng/l for white and red wines, respectively), so, even at such low concentrations, its presence becomes a problem in wine quality. A method for the analysis of TCA in white and red wines has been developed in our laboratory, using headspace solid-phase microextraction and gas chromatography with electron-capture detection. The method, which has been optimized using an experimental design, involves the use of fibres coated with polydimethylsiloxane (PDMS) and allows the analysis of TCA at very low concentrations (under 500 ng/l) with good accuracy (RSD < or = 10%). The limits of quantification of the method are 5 and 8 ng/l for white and red wines, respectively, while the limit of detection is 1 ng/l for both types of wine.

Anisoles↗
PubMed1998

[Attitudes and knowledge of primary care physicians about community breast cancer screening programs].

OBJECTIVE: To find the view of Primary Care doctors in relation to the need for a community programme of breast cancer screening, its effectiveness and the criteria underlying its application. DESIGN: Crossover study. SETTING: Municipal districts of Ciutat Vella and Sant Martí, Barcelona. PARTICIPANTS: General Practitioners (GPs) in the programme. INTERVENTION: A self-filled questionnaire. The questions sought the level of agreement with 11 statements concerning: importance as health problem, effectiveness of the programmes, target population and role of GP. Results were compared for: year of graduation, sex and type of centre. MEASUREMENTS AND MAIN RESULTS: Of 140 doctors, 110 (78.6%) replied. There was majority agreement with all the statements, especially so in: "Breast cancer is one of the three main causes of death in women in Barcelona"; "screening of 50-64-year old women should be recommended"; and "GPs must recommend screening to their patients". CONCLUSION: The replies to the questionnaire indicated agreement with the programme's basic orientation, except for including 40 to 49-year old women in the programme, which the programme did not propose. Hopefully, this consensus will help Primary Care professionals become involved in the screening programme.

Adult↗
PubMed1996

[Relationship between average hospital stay and the rate of early readmissions].

BACKGROUND: To analyze the relationship between length of hospitalary stay and early readmission rate. To assess the hypothesis that those admissions with the lowest length of stay are associated with higher early readmission rate. PATIENTS AND METHODS: Retrospective study of 35,902 hospital admissions. A single admission was selected randomly for each patient. The readmission risk during 31 days were related with length of stay level. Logistic regression model was applied to adjusting by other variables (age, sex, admission year, emergency admission, patient residence, payer). RESULTS: The early readmission rate is lower in the admissions with low outlier length of stay than with not outlier length of stay (5.8% vs 9.8%). After adjusting for other variables the odds ratio is under 1 but not statically significant (0.90; 0.80-1.02). Admissions with high length of stay outlier haver higher early readmission rate (10.4%), with adjusted odds ratio of 1.14 (1.02-1.27). CONCLUSIONS: Admissions with lowest length of stay did not have a high early readmission risk.

Adult↗
PubMed1990

[The reasons for medical and nursing appointments in a primary health care center (Barcelona)].

The programmed visit, which is basically generated by the health care team, permits a rationalization of the demand and the introduction of health promoting activities. We have evaluated our motives (medical and nurse practices) for the appointment of patients during 1987. We have also recorded the age, sex, compliance and source of the appointment in a sample of 198 medical and 223 nurse appointments. 62.5% of the appointed visits corresponded to females and more than 50% to patients over 59 years. The most common type of appointment was to control chronic disease, owing to its high prevalence and the protocolization of its care. In individuals under 45 years appointments were mostly for diagnostic approach and to record the clinical history. The implementation of preventive measures appeared as one of the least common causes. Failure to comply was seen in 25%, being higher in patients under age 45 and in the appointments to record the clinical history. These results point to the need of restructuring the concertation priorities. The health problems of the population and its vulnerability are the factors that should guide health planning.

Age Factors↗
PubMedDate not supplied

[Impact of aging on hospital caseload].

PURPOSE: The progressive ageing of the population has led to a rise in the number of hospital admissions among people older than 64 years. The present study analyses the impact of this phenomenon comparing the case-mix of patients older and younger than 65 years. METHODS: An analysis of the case-mix of all patients admitted to two acute hospitals of Barcelona Spain has been performed using the minimum basic data set of hospital discharges during 1997. The patients were grouped according to diagnosis-related groups (DRG). The characteristics of disease severity and complexity (admissions through emergencies department, DRG average weight, Charlson comorbidity index, average length of stay adjusted by case-mix, percentage of patients with an abnormal length of stay, readmissions and mortality rates were compared between the group of patients of 0-64 years and the group of 65 years and over. A further analysis was carried out for three subgroups of the aged patient population: 65-74, 75-84 and > 84 years. RESULTS: The patients group of 65 years and over presented, in comparison with the younger than 65 qulaction, a higher average weight (1.16 vs 0.96), a higher percentage of admissions through emergency department (49.2% vs 44.4%), more comorbidity (Charlson's Index of 0.98 vs 0.66), a higher average length of stay adjusted DRG (9.4 vs 8.1), a higher percentage of patients with an abnormal length of stay (4.7% vs 3.2%), a higher readmissions percentage (8.6% vs 7.5%) and a higher mortality (6.3% vs 1.6%). All observed differences between the two groups were statistically significant. The analysis of the three subgroups of patients of 65 years and over showed that the variables admissions through the emergency department, length of stay and rate of mortality were significantly related to ageing, while the factor of complexity of comorbidity remained stable for all the subgroup of patients. CONCLUSIONS: The case-mix of patients older than 65 years presents some characteristics associated with a higher complexity, severity and comorbidity, which imply more hospitalization days in relation to younger patients. Hospitals and the health care system at large should design specific strategies to face the fast and progressive ageing of patients admitted to hospitals, since this means a relevant change of the case-mix and the profile of health care requirements.

Age Factors↗
PubMedDate not supplied

Risk adjustment: beyond patient classification systems.

UNLABELLED: Diagnosis related groups (DRGs) are widely used in several countries. Their various versions aim to value the cost of hospital production. In Europe, the patient classification systems and standard weights used are usually the American originals. OBJECTIVES: The objective of this study was to analyse the extent to which DRGs and DRG-weights explain patient cost variability. Different components of patient cost (severity, comorbidities, complications and socioeconomic status), which are not well explained by DRG and which can be approximated by using administrative data, were also analysed. METHODS: A total of 35,262 discharges from two public hospitals in Barcelona were analysed. The Health Care Financing Administration (HCFA)-DRGs and the All Patient Refined (APR)- DRGs were calculated. Severity was adjusted by Disease Staging, and comorbidities and complications were calculated using Elixhauser and Charlson comorbidities groupings. An ecological socioeconomic status indicator was used. Linear regressions were estimated to explain per-patient cost variability. RESULTS: We found that Medicare's DRG-weights explained only 19% of cost variability. Cost-based weights explained nearly 40% (38-42%, depending on the DRG classification used). Exclusion of outliers increased explanatory power to R² = 47-48%. The remaining adjustment variables increased R² to 49-51%. DISCUSSION: Medicare's DRG-weights are not well-suited to Europe. Cost-based DRG-weights and outlier trimming have significantly greater explanatory power. The remaining clinical and socioeconomic variables have considerably less explanatory power but were statistically significant and behaved as expected. Spanish and other European health authorities should adapt DRG-classification systems to their environments for use in hospital production cost valuation.

Diagnosis-Related Groups↗