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J M Bueno

Publications and source records attributed to J M Bueno.

12 recordsLinked to original sources
PubMed2001

Depolarization effects in the human eye.

We have studied the effects of depolarization in the living human eye by using a spatially resolved Mueller-matrix polarimeter [Opt. Lett. 24 (1999) 64]. Results show that the degree of polarization for the central part of double-pass images is about 0.85 and 0.70 for 2 mm and 5 mm of pupil, respectively. This parameter decreases towards the tails of the image. In the plane of the pupil, the degree of polarization also depends on the analyzed area, and it has been related to the different components of the light coming back from the retina. Values of polarizance suggest that the eye presents a slight polarizing power mainly due to the existence of both circular birefringence and dichroic properties. Polarizance is also larger at the central part of double-pass images (about 0.25 on average) and decreases along the radius. In addition, it has been shown that the major retinal layer where the light is reflected does not depend on the state of polarization of the incident light.

Eye↗
PubMed2001

Spatially resolved polarization properties for in vitro corneas.

Spatially resolved polarization properties of in vitro mammalian corneas have been studied by using a Mueller-matrix imaging polarimeter in transmission mode. Sixteen images corresponding to independent combinations of polarization states in the illumination and analyzing pathways are recorded. Spatially resolved Mueller matrices of the samples are calculated from them. Results show that the birefringence of the cornea is almost linear. Although the magnitude of retardation depends on the sample, it is approximately constant at the center and increases towards the periphery. Dichroism and polarizing power are negligible. Maps of the degree of polarization indicate that the cornea basically does not depolarize the totally polarized incident light.

Animals↗
PubMed2001

Polarization and retinal image quality estimates in the human eye.

We have previously studied how polarization affects the double-pass estimates of the retinal image quality by using an imaging polarimeter [Opt. Lett. 24, 64 (1999)]. A series of 16 images for independent combinations of polarization states in the polarimeter were recorded to obtain the spatially resolved Mueller matrices of the eye. From these matrices, double-pass images of a point source for light with different combinations of incoming (first-pass) and outcoming (second-pass) polarization states were reconstructed and their corresponding modulation transfer functions were calculated. We found that the retinal image or, alternatively, the ocular aberrations, are nearly independent of the state of polarization of the incident light (in the first pass). This means that a significant improvement in the ocular optics by using a specific type of polarized light could not be achieved. However, quite different estimates of the retinal image quality are obtained for combinations of polarization states in both the first and the second passes in the double-pass apparatus.

Humans↗
PubMed2000

[The QUALI Project: a quality study of the structure of the primary care teams (PCT) of Catalonia. The Quality Improvement Commission of the Societat Catalana de Medicina Familiar i Comunitària].

OBJECTIVE: To analyse the compliance with the primary health care quality criteria of the Committee for Quality Improvement of the Catalan Society of Family and Community Medicine. DESIGN: Cross-sectional descriptive study. SETTING: Reformed primary care centres (PCC) in Catalonia (186), of which 73 (39.2%) filled out the disk with the results. MEASUREMENTS AND MAIN RESULTS: A total of 202 criteria, divided into five sections (structure and material resources, human resources, work organisation, systems of recording and access, and continuity, confidentiality and participation), were self-evaluated in each PCC. These criteria were defined as basic or optimal and compliance with them was graded from 1 to 4. 72.8% of the criteria were fully complied with. In 7.4% there was partial compliance, and in 19.7% non-compliance. The basic criteria had 74% total compliance, whereas the optimal criteria had 51.9%. The groups with least compliance (sum of the total plus the partial) were records systems (68.6%) and human resources (73.5%). The organisation group had the best compliance (85.5%). By sub-groups, the greatest compliance was found in privacy (93.7%), direct care (89.2%) and recording actions (89.1%). Sub-groups with least compliance were long-term treatments (61.8%), vaccinations (46.4%) and storage (42%). Eight of the 18 criteria not complied with by 50% or more were considered responsibility of the team. There was 37.8% total compliance and 24% partial in the criteria referring to the specific training of primary care professionals. Up to 80% non-compliance was found in quality of long-term prescription records, vaccinations and storage. CONCLUSIONS: The high level of compliance in the sections which depend most on professionals should be noted (accessibility-continuity and organisation). This study is a first approach towards understanding the quality of the structure of PC in Catalonia, and enables proposals for improvement to be set up.

Community Medicine↗
PubMed2000

[Diagnosis of dyslipidemia in primary care: a service to be improved. Results of a multicenter evaluation].

OBJECTIVE: The variability of the quality of care in the primary care procedures to diagnose lipaemia was evaluated. DESIGN: Observation, multi-centred and retrospective study. SETTING: Random sample of 10 primary care centres in the Murcia region. PATIENTS AND OTHER PARTICIPANTS: Patients over 19 with lipaemia detected over the previous twelve months in the general medical clinics at health centres. 500 cases in all were studied (50 per centre). MEASUREMENTS AND MAIN RESULTS: Compliance with criteria of good clinical practice was evaluated. These criteria were formulated by health centre doctors and included: adequate diagnosis, classification into primary or secondary, phenotype, recording of cardiovascular risk factors and assessment of cardiovascular (CV) risk. The differences between the centres studied and the effect of the centre's characteristics (teaching, location, existence of lipaemia programme) and of the patients' (age and gender) were also examined. We found that none of the cases evaluated satisfied the five quality criteria at the same time. Assessment of CV risk and the aetiopathogenic classification were the criteria least complied with (1.5% +/- 1.0). Centres varied considerably. Their characteristics affected the quality of the procedure evaluated, which in all centres had a lot of room for improvement. CONCLUSIONS: The quality of the procedures for diagnosing lipaemia can be considerably improved. It varies a lot from centre to centre.

Adult↗
PubMed2000

Measurement of parameters of polarization in the living human eye using imaging polarimetry.

An imaging polarimeter using liquid-crystal variable retarders (Bueno, J. M., Artal, P. (1999). Double-pass imaging polarimetry in the human eye. Optics Letters, 24, 64-66) has been used to study the parameters of polarization in the living human eye. Retardation introduced by birefringent structures of the eye has been calculated by using a spatially resolved collection of Mueller matrices obtained from series of 16 double-pass retinal images. Results for images with a 2-mm pupil diameter show that although the retardation introduced by the eye in a double-pass varies among individuals, at the central cornea the slow axis is directed along the upper-temporal to lower-nasal line and the ellipticity is close to zero, which indicates the presence of linear birefringence. As pupil size increased, the measured retardation also increased, while ocular birefringence remained linear and azimuthal angle changed without a clear tendency.

Adult↗
PubMed1999

[Fastrach intubation in patients with cervical disease].

The Fastrach laryngeal mask for intubation is a new device designed for blind orotracheal intubation in patients with criteria predictive of difficult airway control. The new device looks like the conventional laryngeal mask but offers a series of design changes that allow orotracheal intubation to be accomplished without visualization of the glottis. The rigid metal tube is bent and incorporates a metal handle; the two fixed bars that prevent the epiglottis from falling and blocking the opening have been replaced by a moveable bar that rises with the passage of the endotracheal tube and the exit of the V-shaped metal tube guides the endotracheal tube that was specially designed for this use. We describe three patients with cervical disease, one with advanced ankylosing spondylitis, one with traumatic luxation of the C6-C7 articulation and one diagnosed of two cervical disk hernias. All their tracheas were intubated without difficulty through the Fastrach mask with the patients' heads in neutral position. Although fiberoptic bronchoscopy is the method of choice in patients with cervical problems, the non-availability of the technique and the need for training in its use make the Fastrach mask an alternative worth considering for such patients.

Aged↗
PubMed1997

Human breast cancer cell metastasis to long bone and soft organs of nude mice: a quantitative assay.

Bone is a common metastatic site in human breast cancer (HBC). Since bone metastasis occurs very rarely from current spontaneous or experimental metastasis models of HBC cells in nude mice, an arterial seeding model involving the direct injection of the cells into the left ventricle has been developed to better understand the mechanisms involved in this process. We present here a sensitive polymerase chain reaction (PCR) method to detect and quantitate bone and soft organ metastasis in nude mice which have been intracardially inoculated with Lac Z transduced HBC cells. Amplification of genomically incorporated Lac Z sequences in MDA-MB-231-BAG HBC cells enables us to specifically detect these cells in mouse organs and bones. We have also created a competitive template to use as an internal standard in the PCR reactions, allowing us to better quantitate levels of HBC metastasis. The results of this PCR detection method correlate well with cell culture detection from alternate long bones from the same mice, and are more sensitive than gross Lac Z staining with X-gal or routine histology. Comparable qualitative results were obtained with PCR and culture in a titration experiment in which mice were inoculated with increasing numbers of cells, but PCR is more quantifiable, less time consuming, and less expensive. This assay can be employed to study the molecular and cellular aspects of bone metastasis, and could easily be used in conjunction with RT-PCR-based analyses of gene products which may be involved with HBC metastasis.

Animals↗
PubMed1997

3D reconstruction of tomographic images applied to largely spaced slices.

This paper presents a full reconstruction process of magnetic resonance images. The first step is to bring the acquired data from the frequency domain, using a Fast Fourier Transform algorithm. A Tomographic Image Interpolation is then used to transform a sequence of tomographic slices in an isotropic volume data set, a process also called 3D Reconstruction. This work describes an automatic method whose interpolation stage is based on a previous matching stage using Delaunay Triangulation. The reconstruction approach uses an extrapolation procedure that permits appropriate treatment of the boundaries of the object under analysis.

Algorithms↗
PubMed1993

[An evaluation study of a scale of diabetological education in primary care].

OBJECTIVE: To devise and evaluate a scale of measurement which would permit evaluation at primary care level, of the knowledge that diabetic patients have of diabetes. Secondly, to ascertain the level of knowledge of the sample of diabetic patients attending the Xixona Health Centre. DESIGN: Non-longitudinal, observational, descriptive study. SETTING: Primary health care (health centre). MEASUREMENTS AND MAIN RESULTS: The degree of internal consistency of the diabetes scale of knowledge (DISK) attained a Cronbach Alpha value of 0.87. The coefficients of correlation of each of the factors--defined a priori (general knowledge, diet, exercise, hygiene and self-regulation)--oscillated between 0.77 and 0.83. The Garret index of corrected difficulty was at 0.64. The homogeneity of each item with the questionnaire showed values above 0.31. The reliability measured by means of the KR20 index was 0.86. The odd-even coefficient of reliability was at 0.89. The mean level of correct answers was 70%. A relation was found between the level of knowledge and the variables age and years the patient had been subject to the condition. No relation was found with the treatment, sex, glycaemia or HbA1C level, nor educational level. CONCLUSIONS: The indices obtained by the scale can be considered to be judiciously acceptable, both in terms of their internal consistency and their ability to characterise. The DISK (ECODI) is, then, a valuable tool in the field of primary health care.

Diabetes Mellitus↗