Biomedical subjects

J M Queraltó

Publications and source records attributed to J M Queraltó.

At least 19 recordsLinked to original sources

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↗

PubMed2001

The EC4 quality manual model.

One of the priorities of the European Confederation of Clinical Chemistry (EC4) is the harmonisation of the clinical laboratory profession in Europe. One of the first steps is to try to harmonise the quality systems, that is, the clinical laboratory organisational structure, responsibilities, procedures, processes and resources involved in quality management. The "EC4 Essential Criteria" were published by the Working Group on Harmonisation of Quality Systems in order to facilitate the development or the update of a quality system in a clinical laboratory, and to encourage international bodies to produce specific Standards for the clinical laboratory. Furthermore, the EC4 Working Group has produced a Quality Manual Model, which includes a sample of quality policy documents and some operational directions for an imaginary laboratory. This Quality Manual Model was prepared following the "EC4 Essential Criteria." Its purpose is that any quality system developed following the Manual could be accredited or certified against any Standard. The EC4 Quality Manual Model will be available, free of charge, to clinical laboratory professionals.

Accreditation↗

PubMed2000

A controlled trial of daily versus thrice-weekly buprenorphine administration for the treatment of opioid dependence.

This study was aimed at determining whether thrice-weekly administration of buprenorphine is as effective as daily administration for treating opioid dependence. A total of 60 treatment-seeking opioid addicts were randomly assigned to take buprenorphine tablets sublingually either every day (8 mg) or thrice-weekly (16 mg on Mondays and Wednesdays and 24 mg on Fridays) over the course of a 12-week, double-blind, parallel trial. The buprenorphine dosing schedule had no significant effect on treatment retention. The rates of opioid-positive urine tests were significantly higher among those subjects who were given buprenorphine thrice weekly (58.5%) than among those who took it daily (46.6%). An analysis of the completers did not detect a significant effect of buprenorphine dosing schedule. The results obtained in our clinical trials indicate the advisability of daily doses of buprenorphine, at least at the beginning of a maintenance programme.

Adult↗

PubMed2000

Prospective evaluation of the contribution of K-ras mutational analysis and CA 19.9 measurement to cytological diagnosis in patients with clinical suspicion of pancreatic cancer.

The aim of this study was to prospectively evaluate the diagnostic contribution of the detection of K-ras mutation and measurement of serum CA 19.9 concentrations to cytological diagnosis in patients with clinical suspicion of pancreatic cancer. These patients had either the presence or absence of a pancreatic mass as determined by imaging procedures. A total of 156 consecutive patients with clinical suspicion of pancreatic cancer or for confirmation and follow-up of their chronic pancreatitis disease were included: 84 patients presenting a pancreatic mass (group 1) and 72 patients without a pancreatic mass (group 2). K-ras mutations were detected by a restriction fragment length polymorphism/polymerase chain reaction (RFLP/PCR) method and CA 19.9 by an immunoluminometric assay. When a pancreatic mass was present, cytology offered a high sensitivity, but with a significant number of inconclusive results and K-ras mutational analysis offered a highly specific test. In the absence of a pancreatic mass, CA 19.9 (cut-off 100 U/ml) increased the sensitivity of the diagnosis by cytology and K-ras mutational analysis did not add significant information. Thus both tests contribute to the clinical decision process when pancreatic cancer is clinically suspected and the cytological report is not conclusive.

Adult↗

PubMed2000

Need for revisiting the concept of reference values.

The reference values concept has been adopted by health care professionals, including clinical chemists, laboratory scientists, and clinicians and simultaneously by all the official organizations in charge of the establishment of legislation. But the estimation of reference limits, and the evaluation of biological variability need to be improved at the level of the procedures, which are currently too long and too expensive and not feasible easily for all laboratories. The procedures for obtaining reference values, if we follow the original documents, are complex, and that is the main reason that clinical chemists or diagnostic kit manufacturers have not used them systematically. There is clearly a need that scientific societies and international organizations propose practical recommendations: 1) Recommendations to describe methods linked to systematic error. * How to transfer reference limits from one laboratory to another laboratory using different methods? * Should we determine reference limits for each method? * How can we differentiate bias due to the populations from these due to the method? Clear collaborations with manufacturers involved in kits and diagnostic systems are needed. 2) Practical recommendations linked to the reference population. * How to select a homogeneous population? (Careful recommendations on the choice between healthy individuals, blood donors and individuals hospitalised for other diseases should be given.) * How to estimate ethnic differences? * How to define the exclusion and inclusion criteria according to quantity? * How to deal with the question of reference limits for unstable periods, aging or old people particularly, when the difference between aging and disease is very difficult to define? 3) Practical recommendations on the statistical methods to be used. * How to make a good choice of the interquartile interval? Should we use and present only the centiles 2.5 or 97.5, or on the contrary should we give other centiles in addition, for example 5, 10, 75, 80, 85, 90? 4) Practical recommendations linked to the use of the concept of the reference values. * How to make this concept more concrete and to have official definitions which are better understandable and not only abstract? * How to demonstrate the value of using simultaneously reference limits and decision limits, and what does each of these limits bring to results interpretation? * How to improve the presentation of the results? How to give more information on biological variability in the laboratory data, taking into account the scientific validity of their determination? Should we use new information techniques and new communication systems for reaching these objectives? The responses to all these questions could only be provided if there is a concerted effort at the international level. Practical recommendations should be given, which would be very useful for a better understanding and use of reference values by laboratory scientists and clinicians.

Clinical Chemistry Tests↗

PubMed2000

Usefulness of EC4 essential criteria for quality systems of medical laboratories as guideline to the ISO 15189 and ISO 17025 documents. European Community Confederation of Clinical Chemistry (EC4) Working Group on Harmonisation of Quality Systems and Accreditation.

Many medical laboratories have made a start with the introduction of quality management systems. However, it is still not clear against which standards such systems should be measured. The existing ISO and CEN standards do not cover essential aspects of medical laboratories. The publication of the EC4 Essential Criteria has stimulated the development of the ISO/Draft International Standard 15189. This standard seems adequate for our type of laboratories. However, it is not easy to read. The EC4 Essential Criteria could well serve as a guide, covering additional aspects, e.g. on total quality management and budget management as required in the EFQM model, that are not (yet) included in the ISO standard. In the present article the EC4 Essential Criteria are cross-referenced with two new international ISO standards, ISO/FDIS 15189 and ISO/FDIS 17025, the latter being the successor of ISO guide 25 and EN 45000. Both new ISO documents are in compliance with the new ISO 9000:2000 standard.

Europe↗

PubMed2000

Reference change value for HbA1c in patients with type 2 diabetes mellitus.

We estimated reference change value and steady state disease biological variation of glycohemoglobin (HbA1c) from serial measurements in 47 clinically stable type 2 diabetes patients whose home-measured capillary glucose was stable throughout the study. Whole blood HbA1c assays were performed by turbidimetric inhibition immunoassay. The analytical imprecision (coefficient of variation) was 7.1% and 5.0% for control materials with HbA1c of 5.1% and 10.7%, respectively (n=152). The sampling interval was 6 months. Patients were classified into three groups (good, acceptable and poor control) according to the American Diabetes Association (ADA) clinical practice recommendations of 1999 based on HbA1c reference interval. Steady state disease biological variation for each control group was 7.9%, 5.4% and 3.9%. HbA1c absolute reference change value was 1.42, 1.50 and 1.37%, or as relative reference change value, 29.1%, 24.4% and 17.8%, respectively. The analytical goal, defined as one-half of the biological variation, was lower than 3.9% for well-controlled patients.

Aged↗

PubMed1999

Neural networks for the biochemical prediction of bone mass loss.

Neural networks are specialized artificial intelligence techniques that have shown high efficiency in dealing with complex problems. Paradigms such as backpropagation have been successfully applied in a number of biomedical applications, but not in attempts to identify women at risk of postmenopausal osteoporotic complications. In this paper, several neural networks were trained using different combinations of biochemical variables as inputs. Bone densitometric measurements in Ward's triangle and in the spinal column were used as separate classification criteria (outputs) between slow and fast bone mass losers. The most parsimonious model with the best performance included plasma concentrations of estrone, estradiol, osteocalcin, parathyrin and urine concentrations of calcium and hydroxyproline (expressed as ratio to creatinine excretion) as input neurons; ten neurons in a single hidden layer; and one neuron in the output layer. Diagnostic efficiency was 76% in Ward's triangle and 74% in the spinal column; sensitivity was 70 and 81%, and specificity was 77 and 65%, respectively. Linear discriminant analysis showed a diagnostic efficiency of 66% in Ward's triangle and 64% in the spinal column, sensitivity was 55 and 86%, and specificity was 75 and 13%, respectively. We conclude that performance of the stepwise discriminant analysis was not superior to the neural networks.

Adult↗

PubMed1998

Additional Essential Criteria for Quality Systems of Medical Laboratories. European Community Confederation of Clinical Chemistry (EC4) Working Group on Harmonisation of Quality Systems and Accreditation.

Essential Criteria for Quality Systems of Medical Laboratories have been published recently by the European Community Confederation of Clinical Chemistry (EC4) Working Group on Harmonisation of Quality Systems and Accreditation. The Essential Criteria address the majority of critical aspects of quality management in the medical laboratory. They have been accepted by the EC4 General Assembly and are endorsed by the Forum of European Societies for Clinical Chemistry (FESCC). However, a supplement to the Essential Criteria was necessary, addressing two aspects, which are only partly covered by the Essential Criteria: the management of resources and point of care testing. Thus, the EC4 Working Group on Harmonisation of Quality Systems and Accreditation has decided to formulate Additional Essential Criteria for Quality Systems of Medical Laboratories, directed at the issues of management of resources and point of care testing. Criteria on management of resources address financial aspects, information logistics and acceptance by clients. Criteria on point of care testing address responsibilities, education of non-laboratory staff and operational aspects. The Additional Criteria are supplementary to the previously published Essential Criteria and should be read as an integral part of these.

Accreditation↗

PubMed1997

Predicting outcome of lithium added to antidepressants in resistant depression.

This study was conducted to assess the predictive value of different variables including the response to dexamethasone suppression test (DST), in 105 patients with resistant depression after the addition of lithium (600 to 800 mg/day) for 4 weeks to antidepressant medication. Clinical remission was observed in 57 patients and no improvement in 48. A dramatic and rapid relief of depression occurred in 12 patients. Variables with significant or marginally significant differences between responders and non-responders were included in a stepwise logistic regression model. Weight loss (P = 0.0013) and depressive psychomotor activity (P = 0.045) in the Newcastle diagnostic index (NDI) scale, and overall score of the Hamilton Rating Scale for Depression (HRSD) before adding the lithium (P = 0.0039) were significantly associated with clinical remission. The difference in post-DST cortisol plasma levels between both groups was marginally significant. The logistic equation resulted in a sensitivity of 78% and a specificity of 65% and total correct classification of the lithium-added response of 72%. The clinical profile of patients who improve with the addition of lithium may include significant weight loss, psychomotor retardation and possibly, poor control of cortisol secretion. Partial remission before adding lithium as well as endogenomorphic traits according to NDI may also be considered additional criteria for response.

Adolescent↗

PubMed1997

Within-subject variation of carcinoembryonic antigen in colorectal cancer -- application of reference of change values and individual reference ranges to patient follow-up.

Dynamic interpretation of results is an alternative approach to the conventional cut-off procedure. Reference change limit is a valuable reference point to interpret dynamically tumour marker values when only very few serial results can be obtained from a patient after treatment. In this paper, a reference change limit of 2.0 microg/l was estimated for carcinoembryonic antigen in patients with complete remission of colorectal cancer. This figure means that a difference greater than 2.0 microg/l has at least a chance of being statistically significant (at 0.05 probability). As complementary information to the reference change limits, with more than four successive results, a simple time series model can be used to obtain predictive limits for the next observation.

Adenocarcinoma↗

PubMed1997

Essential criteria for quality systems in medical laboratories.

The introduction of total quality systems in medical and clinical laboratories and accreditation of these laboratories is gaining more and more interest. In several countries laboratories have set up quality systems, and accrediation schemes are also operating. The standards of these schemes have much in common although several differences exist. There exists uncertainty in several countries on the choice of a system. Laboratory specialists are confronted with a new way of thinking concerning the management and daily practice of their laboratories. It is not clear, which standards should be used as a basis, and certainly not how to interpret such standards. Particulary in the European Union, harmonisation of criteria for quality systems is desirable. In the present paper, the document entitled "Essential Criteria for Quality Systems in Medical Laboratories" is presented. The document has been accepted in the general Assembly of the European Communities Confederation of Clinical Chemistry (EC4) and by the working group on Good Laboratory Services of the European Council on Laboratory Medicine (ECLM). The criteria in the document are focussed on the particular situation of medical laboratories, including pre- and post-analytical aspects. Reference is made, where applicable, to EN 45001, ISO 9001 and ISO guide 25 draft 3.

Chemistry, Clinical↗

PubMed1995

Quality and accreditation systems in clinical biochemistry in the European Union.

The European Community Confederation of Clinical Chemistry (EC4) formed in Nice in April 1993 has established a working group on laboratory accreditation. The aim of the group is to explore the possibilities for harmonisation of accreditation and quality systems in clinical laboratories in the European Community (EC). It is felt essential that professions should play a key role in the process, and that the principle of subsidiarity should be observed in relation to implementation and organisation in individual member states. The first task has been to collect information concerning such systems. In September 1993 a questionnaire was distributed to the twelve IFCC related societies for clinical chemistry in the EC. By December 1994 eleven societies had responded. The questionnaire related to the existence or planned introduction of quality and accreditation systems, the basis of the standards used and requirements for analytical aspects and qualifications of staff as well as professional aspects. Questions also addressed the way in which inspection were organised, the selection and training of inspectors, the organisation of systems and what interest there was in harmonisation. The results of this study are presented in this paper.

Accreditation↗

PubMed1994

Clinical biochemistry education in Spain.

Clinical biochemistry in Spain was first established in 1978 as an independent specialty. It is one of several clinical laboratory sciences specialties, together with haematology, microbiology, immunology and general laboratory (Clinical analysis, análisis clinicos). Graduates in Medicine, Pharmacy, Chemistry and Biological Sciences can enter post-graduate training in Clinical Chemistry after a nation-wide examination. Training in an accredited Clinical Chemistry department is 4 years. A national committee for medical and pharmacist specialties advises the government on the number of trainees, program and educational units accreditation criteria. Technical staff includes nurses and specifically trained technologists. Accreditation of laboratories is developed at different regional levels. The Spanish Society for Clinical Biochemistry and Molecular Pathology (SECQ), the national representative in the IFCC, has 1600 members, currently publishes a scientific journal (Química Clinica) and a newsletter. It organizes a continuous education program, a quality control program and an annual Congress.

Biochemistry↗

PubMed1994

Growth hormone response to growth hormone-releasing hormone stimulation in oligozoospermic patients.

OBJECTIVE: To evaluate the GH response to growth hormone-releasing hormone (GH-RH) stimulation in oligozoospermic men. SETTING: Outpatient Clinic of Andrology at the Fundación Puigvert and the Department of Clinical Chemistry, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. PATIENTS: Fifteen oligozoospermic patients and 15 normozoospermic fertile men matched for age and body mass index. INTERVENTION: Endocrine status was determined by assay of basal levels of gonadotropins (FSH, LH), T, E2, inhibin, and insulin-like growth factor I (IGF-I). Serum GH levels were measured before and after GH-RH administration. RESULTS: GH response to GH-RH was significantly greater in patients than in controls. There was a positive correlation between the GH response and IGF-I levels in oligozoospermic patients only. Regression analysis showed a significant negative association of GH peak with inhibin after controlling for IGF-I in oligozoospermic patients. CONCLUSION: The results indicate that there is an altered responsiveness of pituitary to GH-RH administration in oligozoospermic patients; this did not appear to be due to the influence of gonadal steroid levels but rather to inhibin or some related peptide.

Adult↗

PubMed1993

On the calculation of reference change values, with examples from a long-term study.

Reference change values (sometimes called critical differences) indicate statistically important changes between test values obtained on two occasions. They are commonly computed from the median (or mean) within-subject variance observed in repeated test measurements on a number of subjects. With this computational approach, all observed within-subject variances are assumed to be estimates of a constant true variance, the same for all individuals. Moreover, any possible correlation between successive values is almost always ignored. This simplified methodology differs from the method originally proposed for computing reference change values, which accounts for variability in true variances and for serial correlation. From data obtained from repeated measurements over 2 to 5 years in 72 physically healthy subjects, we computed and compared reference change values in 18 serum analytes, using the simplified method and the originally proposed procedure. Although the original method is more complicated and requires a computer program, we believe that it produces more-reliable reference change values than those obtained by the simplified approach. The former are generally larger, but remain sensitive to clinically important changes in the individual.

Adolescent↗

PubMed1993

Dipyrone interference on several common biochemical tests.

We studied the effect in vitro and in vivo of dipyrone on the determination of several biochemical tests in two analyzers, a Hitachi 747 and a Kodak Ektachem 700. From studies in vitro, we found significant interference by dipyrone (P < 0.05) in the determination of creatine kinase (CK), lactate dehydrogenase (LD), uric acid, triglycerides, cholesterol, aspartate aminotransferase, alanine aminotransferase, and urea nitrogen with both instruments, and in the determination of creatinine in the Ektachem analyzer. We also studied the effect of intravenously administered dipyrone in 14 patients. Dipyrone interfered significantly (P < 0.05) in the determination of CK, LD, uric acid, triglycerides, and cholesterol with both instruments, and creatinine only with the Ektachem analyzer. Using high-performance liquid chromatography (HPLC), we measured concentrations of dipyrone in the serum of patients who had received the drug and observed a negative correlation between the concentrations of dipyrone in the blood and the percentage of each analyte concentration.

Alanine Transaminase↗

PubMed1988

Urinary phenylacetic acid excretion in depressive patients.

Phenylacetic acid (PAA), a metabolite of phenylethylamine, has been found in the urine of depressed patients at lower levels than in control subjects. It has been suggested that the determination of PAA in urine could be used as a biological marker of the depressive condition. In this study the levels of PAA in urine were investigated by gas-liquid chromatography in 39 patients diagnosed as having major depression according to DSM-III criteria, and in 32 healthy subjects. The values found in the patients were markedly lower than in controls. No relationship was found between the decrease of PAA excretion and weight loss. Using a discriminant equation, a value of 69% was obtained for both sensitivity and specificity. The results suggest that the determination of urine PAA could be a biological parameter comparable to the dexamethasone suppression test.

Adult↗