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S Ballesteros

Publications and source records attributed to S Ballesteros.

At least 19 recordsLinked to original sources
PubMed2006

Is it possible to reduce the number of endomyocardial biopsies with new immunosuppressive drugs?

INTRODUCTION: Using previous immunosuppressive regimens the considerable number of rejections of heart transplantations required routine surveillance myocardial biopsies, particularly during the early months. More effective immunosuppressive regimens would probably allow routine biopsies to be reduced. Our objectives were to assess the incidence of and the time to rejection with a new immunosuppressive protocol, considering the possibility of reducing the number of routine biopsies. MATERIALS AND METHODS: We undertook a retrospective study of patients who had undergone heart transplantation from January 2002 to August 2005 and who received induction therapy with Daclizumab (two doses) and maintenance therapy with tacrolimus + mycophenolate + low doses of steroids. RESULTS: Among 42 patients, 13 (31%) showed myocardial rejection in the first 3 months. All episodes were grade 3A and none had hemodynamic consequences. After 3 months, three patients (7.1%) experienced 3A rejection and 1 (2.4%), grade 4 acute rejection after ceasing medical treatment. Each episode of rejection was predictable, either owing to reduction in immunosuppression therapy or to a previous history of rejection. CONCLUSIONS: The majority of rejection episodes occur in the first 3 months posttransplantation. After that time, the incidence of rejection is less and clinically predictable. Therefore, surveillance biopsies should be limited to the first 3 months, and performed later either in symptomatic patients (with a history of previous rejection) or in those whose immunosuppressive therapy needs to be reduced.

Biopsy↗
PubMed2006

Combination therapy with sildenafil and bosentan reverts severe pulmonary hypertension and allows heart transplantation: case report.

INTRODUCTION: Severe pulmonary hypertension with no response to vasodilators on an acute hemodynamic study is a contraindication to cardiac transplantation. The development of oral pulmonary vasodilators improves the prognosis in these patients. We present the case of a patient whose admission to the waiting list for cardiac transplantation was possible after 6 months of combination therapy with Sildenafil and Bosentan. CASE REPORT: The patient was a 50-year-old man with severe dilated alcohol-induced cardiomyopathy. A pretransplantation study, including a right hemodynamic analysis, revealed irreversible pulmonary hypertension, with 59 mm Hg mean pulmonary artery pressure and 6.4 Wood IU pulmonary vascular resistance, with no response to acute vasodilators with nitric oxide or prostacyclin. Initially, heart transplantation was not possible and the patient started treatment with oral Sildenafil. After 6 months there was no improvement in echocardiographic or hemodynamic parameters, and combination therapy with Bosentan was started. With the combination therapy, the patient progressively improved clinically and hemodynamically, the pressures becoming normal at the sixth month, at which time he was included on the waiting list for a heart transplantation. Eight months later he received a graft with a good posttransplantation course, no right ventricular failure in the acute phase, and absence of pulmonary hypertension on echocardiogrphic and invasive studies. CONCLUSION: Combinations of an oral pulmonary vasodilator with diverse action mechanisms may represent an alternative for patients with irreversible pulmonary hypertension who do not respond to monotherapy.

Antihypertensive Agents↗
PubMed2005

Virological analysis in the diagnosis of sudden children death: a medico-legal approach.

Infections are considered to be an important cause of unexpected death in children. It has also been assumed that respiratory viruses are involved in the genesis of sudden infant death syndrome (SIDS). The Spanish National Institute of Toxicology and Forensic Sciences act as the forensic reference centre for Spain. We analyse the experience of this centre in the virological study of 64 cases of sudden children death where viral serology, virological cultures, herpesviruses polymerase chain reaction (PCR) and electron microscopy were performed. According to pathological findings, death could only be attributed to an adenovirus infection in one amygdalitis with upper airways stenosis and asphyxia. Human herpes virus 6 (HHV-6) was detected by PCR in one case with pathological findings characteristic of SIDS. Recent infection by respiratory syncytial virus (RSV), Epstein-Barr virus (EBV) and cytomegalovirus (CMV) were also detected. Meanwhile, 85.9% of the cases yielded negative viral results. Twenty-eight infants were finally categorised as SIDS. Pathological findings of infection were detected in 12 patients despite the negativity of viral analyses. Although viral infection is an uncommon cause of sudden children death, a complete microbiological investigation will help to solve the puzzle of SIDS. Definitive guidelines for microbiological analyses need to be updated whilst new pathogens are discovered or new techniques are implemented in order to clarify unsolved cases.

Child, Preschool↗
PubMed2005

Latex agglutination for bacterial antigens and meningococcus PCR: two useful tools in legal sudden deaths.

Bacterial infections are considered to be a major cause of sudden deaths. The recognition of infections caused by Neisseria meningitidis is an essential duty of medicolegal offices due to the risk of secondary cases. Since other microorganisms, such as Haemophilus influenzae and Streptococcus pneumoniae, are also involved in infectious sudden deaths, the identification of the pathogen responsible for death is essential in order to establish a positive diagnosis while also preventing secondary meningococcal cases. However, because of the unreliability of culture methods used for autopsy specimens and the fragile nature of the microorganisms, other techniques were used. In this study, the detection of specific antigens of N. meningitidis (serogroups A, B, C, Y and W135), H. influenzae type b, S. pneumoniae and Group B Streptococcus was undertaken in 40 samples from sudden death cases in legal procedures with a latex agglutination test. In addition, a meningococcus polymerase chain reaction (PCR) assay (ctrA, crgA and siaD genes) was also used as a corroboration method for positive N. meningitidis agglutinations. Eleven cases of sudden death were confirmed to be due to meningococcus while one case was confirmed to have been caused by H. influenzae type b fulminant epiglottitis. Rapid laboratory diagnosis of meningococcal infection allowed contacts management and notification to the health authorities. From the point of view of the authors, forensic diagnosis of unascertained deaths should include latex agglutination and meningococcus PCR when a fulminant infection by N. meningitidis or H. influenzae is suspected as well as in deaths where the cause is unclear.

Adolescent↗
PubMed1998

Symmetry in haptic and in visual shape perception.

Four experiments tested the hypothesis that bilateral symmetry is an incidental encoding property in vision, but can also be elicited as an incidental effect in touch, provided that sufficient spatial reference information is available initially for haptic inputs to be organized spatially. Experiment 1 showed that symmetry facilitated processing in vision, even though the task required judgments of stimulus closure rather than the detection of symmetry. The same task and stimuli failed to show symmetry effects in tactual scanning by one finger (Experiment 2). Experiment 3 found facilitating effects for vertically symmetric open stimuli, although not for closed patterns, in two-forefinger exploration when the forefingers had previously been aligned to the body midaxis to provide body-centered spatial reference. The one-finger exploration condition again failed to show symmetry effects. Experiment 4 replicated the facilitating effects of symmetry for open symmetric shapes in tactual exploration by the two (previously aligned) forefingers. Closed shapes again showed no effect. Spatial-reference information, finger movements, and stimulus factors in shape perception by touch are discussed.

Form Perception↗
PubMed1997

Haptic discrimination of bilateral symmetry in 2-dimensional and 3-dimensional unfamiliar displays.

In five experiments, we tested the accuracy and sensitivity of the haptic system in detecting bilateral symmetry of raised-line shapes (Experiments 1 and 2) and unfamiliar 3-D objects (Experiments 3-5) under different time constraints and different modes of exploration. Touch was moderately accurate for detecting this property in raised displays. Experiment 1 showed that asymmetric judgments were systematically more accurate than were symmetric judgements with scanning by one finger. Experiments 2 confirmed the results of Experiment 1 but also showed that bimanual exploration facilitated processing of symmetric shapes without improving asymmetric detections. Bimanual exploration of 3-D objects was very accurate and significantly facilitated processing of symmetric objects under different time constraints (Experiment 3). Unimanual exploration did not differ from bimanual exploration (Experiment 4), but restricting hand movements to one enclosure reduced performance significantly (Experiment 5). Spatial reference information, signal detection measures, and hand movements in processing bilateral symmetry by touch are discussed.

Adult↗
PubMed1996

The effects of variation of an irrelevant dimension on same-different visual judgments.

In a series of experiments observers judged whether two visual tachistoscopically presented shapes were the same or different in a relevant dimension, and had to ignore the graded variation on an irrelevant dimension that appeared concurrently with the relevant dimension. Experimental results from judgments in orientation, size and brightness failed to support the normalization hypothesis. The hypothesis predicts a monotonous increase in RTs with the increasing degree of disparity in the irrelevant dimension in same as well as in different comparisons. The results were interpreted in terms of the type of dimensions used to construct the shapes. It was suggested that with separable stimulus dimensions normalization would not be necessary. However, interference might appear when the stimuli to be compared were generated from a combination of more integral dimensions.

Adult↗
PubMed1992

Priming and recognition of transformed three-dimensional objects: effects of size and reflection.

In 2 experiments exploring memory for unfamiliar 3-dimensional objects, Ss studied drawings under conditions that encouraged encoding of global object structure. Implicit memory for objects was assessed by a judgment of structural possibility; explicit memory was assessed by recognition. The principal manipulation was the relationship between the sizes or the left-right parities of the studied and tested objects. Priming was observed on the possible-impossible object decision task despite transformations of size or reflection. Recognition, by contrast, was significantly impaired by the transformations. These results suggest that a structural description system constructs representations of objects invariant over size and reflection, whereas a separable episodic system encodes these transformations as properties of an object's distinctive representation in memory.

Adult↗
PubMed1987

Visual hemispheric asymmetry and right-left confusion.

From 357 university students two groups of 8 women each were selected, one group with high right-left confusion and the other without such confusion according to self-reports. Reaction times to stimuli tachistoscopically presented in visual hemifields were recorded to estimate the relationship between perceptual asymmetry and right-left confusion. A significant difference between hemifields and an interaction of hemifield by group appeared, whereas asymmetry in the highly confused group was not so related. According to a model of cerebral functioning in the formation of the body image, these results suggest subjects with high right-left confusion have greater hemispheric bilateralization.

Adolescent↗
PubMedDate not supplied

Acute nitrobenzene poisoning with severe associated methemoglobinemia: identification in whole blood by GC-FID and GC-MS.

A rare fatal case of self-poisoning with nitrobenzene following oral ingestion is reported. On presentation to the hospital, severe methemoglobinemia (70%) was observed in an 82-year-old male who had ingested 250 mL of an unknown substance in the previous 24 h. Methylene blue and exchange transfusion were the therapeutic methods applied in the treatment of the methemoglobinemia. Forty-eight hours after ingestion, a blood sample was collected in ICU and sent to our laboratory. We detected that the blood contained 3.2 microg/mL of nitrobenzene. The determination of nitrobenzene was performed using the combination of GC-FID for screening analysis and quantitation and GC-MS for confirmation of the obtained results.

Administration, Oral↗