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Biomedical subjects

R Lafuente

Publications and source records attributed to R Lafuente.

At least 19 recordsLinked to original sources
PubMed2005

Adsorptive granulocyte/monocyte apheresis for the treatment of refractory rheumatoid arthritis: an open pilot multicentre trial.

OBJECTIVE: To assess the efficacy and safety of adsorptive granulocyte and monocyte apheresis (GCAP) in patients with refractory rheumatoid arthritis (RA). METHODS: Patients with active and refractory RA were treated with weekly GCAP sessions using a column filled with acetate beads (Adacolumn) over five consecutive weeks. Clinical assessments and response to therapy were analysed at weeks 5, 7, 12 and 20 in an open multicentre trial. The primary outcome measure of clinical response was 20% improvement in the American College of Rheumatology criteria (ACR20) at week 20. EULAR (European League Against Rheumatism) response criteria, based on the disease activity score for 28 joints (DAS28) and disability using the Health Assessment Questionnaire (HAQ), were also assessed. RESULTS: Of 27 patients, 81.5% were women with mean disease duration of 14.4 yr. The mean number of previous disease-modifying antirheumatic drugs (DMARDs) was 3.7, and 48.1% of patients had previously failed on biologicals. On an intention-to-treat basis, 40.7% of patients achieved an ACR20 and 44.4% a therapeutic EULAR response at week 20. These percentages were 50 and 54.5% in 22 patients who completed the trial. In the 10 completers who had previously failed on biologicals, an ACR response was achieved in four patients (ACR20, two; ACR50, one; ACR70, one). A significant decrease was recorded in different ACR response components, including the tender joint and swollen joint counts, pain score and patient and physician global disease assessments, as well as the DAS28 index; most of them improved after week 5. ESR and CRP, but not the HAQ score, had decreased significantly at week 20. The treatment was well tolerated and only one serious adverse event related to the study procedure was documented (sepsis due to a catheter infection). CONCLUSIONS: GCAP treatment led to significant clinical improvement in a subset of patients with RA who had failed to respond to DMARDs or biologicals. Further large, placebo-controlled studies are warranted to fully assess the therapeutic value of GCAP for refractory RA.

Adult↗
PubMed2000

Quantitative assessment of gait deviation: contribution to the objective measurement of disability.

Three biomechanical parameters based on force plate measurements were defined as indicators of gait deviation. Symmetry was specified as the relative difference in stance time and vertical impulse loading between both feet, constancy as the mean S.D. of the force curves for one subject under a specified gait condition and discrepancy as the average difference between the individual gait pattern and the expected force curves, normalised by the value of the S.D. in a control group. One hundred and forty four patients with osteoarthritis (OA) of the lower extremity and 144 control subjects were studied. There were 45 patients with OA of the hip, 54 of the knee and 45 of the ankle and their function was determined using the Harris Hip score, the hospital for special surgery knee score and the Mazur ankle score, respectively. The temporal asymmetry indicator was more sensitive to unilateral joint affliction, whereas the discrepancy indicators were sensitive to the presence of OA. Both correlated with the patient's function as measured by the relevant clinical score. A significant increase of gait discrepancy was detected in the arthritis group when patients were asked to walk at faster speeds; whilst walking barefoot led to an unexpected reduction of intra-subject kinetic variability. Our results confirm the validity and usefulness of the gait deviation concept in patients with OA.

Adolescent↗
PubMed1998

Design and test of neural networks and statistical classifiers in computer-aided movement analysis: a case study on gait analysis.

OBJECTIVE: To describe the methods for designing and testing diagnostic systems in movement analysis and to verify the clinical usefulness of neural networks and statistical classifiers in a case study. DESIGN: Connectionist and statistical models trained and tested with measured data. BACKGROUND: A basic need in rehabilitation and related fields is to efficiently manage the vast information obtained from a movement analysis laboratory. Many studies have dealt with the interpretation of measured variables in order to correlate objective descriptors to the presence and/or severity of specific neuromusculoskeletal disorders or their consequences. This traditional analytical approach has been complemented in the last decade by new non-linear classification tools called neural networks. METHODS: A gait analysis study on 148 lower limb arthrosis patients and 88 age-matched control subjects. Pathological and healthy gait patterns obtained from force plates wer discriminated by means of multilayer perceptrons and statistical classifiers. RESULTS: Ten input features were enough to train a multilayer perceptron with six hidden neurons. The discrimination rate of the neural net was 80% after cross-validation, significantly higher (P<0.05) than the performance of a Bayes quadratic classifier (about 75%). A great variance due to a small cross-validation set could be demonstrated. CONCLUSIONS: Strict statistical requirements must be observed for designing a neural network. Although these models attain a better performance than conventional statistical approaches, the benefits they bring are sometimes not sufficient to justify their use. Furthermore, clinicians routinely involved in critical decisions may not consider such diagnostic systems reliable enough.

Journal Article↗
PubMed1998

Application of fuzzy logic techniques for the qualitative interpretation of preferences in a collective questionnaire for users of wheelchairs.

Active participation of users in the evaluation of technical aids is essential, since they are part of the interface with the system and constitute a fundamental source of design criteria. In this study, 88 active users of wheelchairs were interviewed by means of a written questionnaire about their opinion concerning the adaptation of his/her wheelchair to the office workplace. A conceptual framework was introduced linking objective measurements of the user-wheelchair interface to the subjective preferences expressed by the user. Discriminant analysis was used in order to select and quantify the importance of the most significant factors influencing the user's opinions. Fuzzy logic was introduced for the qualitative interpretation of the relationship between those significant factors, based on an inductive algorithm for generating fuzzy rules. Fuzzy logic enables a person to model the uncertainty within the subjective formulation of knowledge or opinions. From the results, a mismatch between actual performance of conventional wheelchairs and requirements of office work became evident. The proposed methods make it possible to determine reliable rules explaining subjective preferences; thus, they provide a flexible means of interpreting user questionnaires and obtaining new design criteria.

Equipment Design↗
PubMed1990

Abnormal chromatin clumping in leucocytes: a clue to a new subtype of myelodysplastic syndrome.

We report 6 patients with myelodysplastic syndrome, all of whom showed a bizarre nuclear anomaly within the neutrophils that was characterized by extensive clumping of chromatin into large blocks separated by clear zones, generally associated with a lack of segmentation. Anaemia, thrombocytopenia, variable leucocyte counts with leucoerythroblastic picture, marrow hypercellularity with granulocytic hyperplasia and moderate dysplastic changes in erythroblastic and megakaryocytic lines were present at diagnosis. 2 patients had normal karyotypes and a 3 showed a deletion of chromosome 14. 5 out of 6 patients had pneumonia at diagnosis. The median survival was short (5 months) and haemorrhagic complications were the cause of death in 4 patients. The clinical features and the evolution of these and other reported cases suggest that the presence of abnormal chromatin clumping in leucocytes might be a clue to a new subtype of myelodysplastic syndrome.

Aged↗
PubMed1990

[Erythroid colonies derived from BFU-E from the bone marrow in a patient with type I congenital dyserythropoietic anemia].

The findings of in vitro culture of bone-marrow BFU-E from a patient with type I dyserythropoietic anaemia are reported, scarce data being seemingly available in the literature. The number of BFU-E in the culture was increased four-fold with respect to the normal values. The morphologic study of the colonies showed in all cases varying number of erythroblasts with internuclear bridges (5-20%). Upon ultrastructural examination of the colonies, a great number of erythroblasts exhibited morphologic alterations, spongy chromatin and internuclear bridges being commonest. These findings suggest that an alteration of the progenitor erythroid cells exists in type I dyserythropoietic anaemia, whereas the morphological defects appreciated show great variation in the progeny of each BFU-E.

Adult↗
PubMed1989

[Pseudohemopathy caused by rhabdomyosarcoma].

A 26-year-old male with a primary rhabdomyosarcoma of maxillary sinus is reported. The tumor was initially mistaken for an anaplastic Ki-1 positive anaplastic lymphoma in the histological preparation, owing to its high indifferentiation degree. After a smear study it was categorized as IEA, and chemotherapy of CHOP type was started; after two courses, local telecobalt therapy was given. After this was completed, the disease showed a progression, involving the bone marrow and resulting in clinical and cytological features consistent with acute leukemia. At that time we saw the patient for the first time. He is presently in complete remission after having started polychemotherapy of CVADIC type. After a commentary on the major study steps that led to the diagnosis, the crucial role of electron microscopy and, particularly, immunocytology for the correct identification of anaplastic tumors is emphasized.

Adult↗
PubMed1989

Circulating erythroid and megakaryocytic progenitors in polycythaemia vera and essential thrombocythaemia.

We studied the behaviour in culture of erythroid and megakaryocyte progenitor cells (BFU-E, CFU-MK) obtained from peripheral blood (PB) in 38 patients: 15 with essential thrombocythaemia, 3 with reactive thrombocytosis, 16 with polycythaemia vera and 4 with secondary polyglobulia. Clonal erythroid growth without added erythropoietin was observed in all patients with polycythaemia vera and in 5 out of 15 with essential thrombocythaemia, but in none of the patients with reactive thrombocytosis or secondary polyglobulia or in controls. When the CFU-MK were cultured without phytohaemagglutinin-stimulated medium (PHA-LCM), all patients with essential thrombocythaemia and 7 out of 16 with polycythaemia vera showed circulating CFU-MK but none of those with reactive thrombocytosis or secondary polyglobulia or controls did so. This study indicates that the growth in vitro of megakaryocytic and erythroid progenitors from such a readily available source as peripheral blood can be valuable in the diagnosis of certain borderline cases of thrombocytosis or erythrocytosis.

Cells, Cultured↗