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Biomedical subjects

F Calleja

Publications and source records attributed to F Calleja.

15 recordsLinked to original sources
PubMed2006

Real-space direct visualization of the layer-dependent roughening transition in nanometer-thick Pb films.

By means of variable-temperature scanning tunneling microscopy and spectroscopy we studied the thickness-dependent roughening temperature of Pb films grown on Cu(111), whose electronic structure and total energy is controlled by quantum well states created by the spatial confinement of electrons. Large scale STM images are employed to quantify the layer population, i.e., the fraction of the surface area covered by different Pb thicknesses, directly in the real space as a function of temperature. The roughening temperature oscillates repeatedly with bilayer periodicity plus a longer beating period, mirroring the thickness dependence of surface energy calculations. Conditions have been found to stabilize at 300 K Pb films of particular magic thicknesses, atomically flat over microns.

Journal Article↗
PubMed2004

Contrast reversal and shape changes of atomic adsorbates measured with scanning tunneling microscopy.

Systematic, quantitative comparisons between scanning tunneling microscopy (STM) experiments and first principles simulations of O(2 x 2)/Ru(0001) have been performed. The shape of the atomic adsorbates in the images depends strongly on the tunneling resistance and changes reversibly from circular (high resistance) to triangular (low resistance). In addition, after adsorption of oxygen on the STM tip we observe a contrast reversal on the surface, confirmed by extensive numerical simulations.

Journal Article↗
PubMed1996

Mitral valve surgery through right thoracotomy.

UNLABELLED: Two years ago we had, for technical reason to resuscitate right thoracotomy (RT) to approach the mitral valve. Since then we have used it in 23 patients. 18 of them had had at least one operation through a medium sternotomy. In 5 cases the right approach was electively used, as first choice to repair or replace the mitral valve. Intracardiac surgery was performed routinely with moderate hypothermia and controlled ventricular fibrillation with the aorta unclamped. Only in one case, an unexpected aortic incompetence forced us to cross-clamp the aorta and replace the valve using crystalloid cold cardioplegia. 14 patients underwent mitral valve replacement. In 5 cases a leaking mitral prosthesis was successfully reattached and in 4 cases the native valve was repaired. 2 patients died (9%) for reasons unrelated to the technique. We did not have any case of air embolism. CONCLUSION: 1) RT is very useful to approach the mitral valve, specially in patients who previously had: a) several sternotomies, b) postoperative mediastinitis, specially if treated by omentoplasty, c) coronary artery bypass; 2) the good view to the mitral valve obtained with the aorta unclamped, make us think if the mitral repair should elective done through this approach.

Female↗
PubMed1994

Comparative evaluation of pentoxifylline, buflomedil, and nifedipine in the treatment of intermittent claudication of the lower limbs.

In the light of the current controversy surrounding the use of hemorheologic and vasodilator drugs in the treatment of peripheral arteriosclerosis, a comparative study was designed in order to evaluate the efficacy of pentoxifylline, buflomedil, and nifedipine in 45 patients with peripheral arterial disease (Fontaine stage II). The patients in this prospective randomized study were divided into three groups: 15 patients received pentoxifylline treatment (1,200 mg/day), 15 were treated with buflomedil (600 mg/day), and 15 with nifedipine (60 mg/day). Response to treatment was assessed at the start of the study and after forty-five and ninety days, by clinical examination, Doppler test, strain test, and digital occlusion plethysmography using a strain gauge ring. Pentoxifylline was significantly more effective (P < 0.05) than buflomedil and nifedipine at ninety days in improving walking performance, resting toe pressure, resting and postexercise ankle/brachial pressure ratio, and basal/postischemic toe-pulse ratio. Significant differences within groups were also noted for initial claudication, toe peak-flow time, pulse reappearance time (PRT/2), and maximum postischemic flow time, together with significant intergroup variables. In conclusion, pentoxifylline proved more effective than the other drugs tested in: 1. improving distal pressure and resting microcirculatory blood flow; 2. increasing postexercise distal flow, ratios, and pressures and enabling faster recuperation of basal pulse rates; 3. increasing initial claudication distance in the strain test within the test group and achieving a greater absolute subjective claudication distance than that obtained using the other treatments.

Adult↗
PubMed1994

Operative management of a persistent sciatic artery aneurysm.

A 60-year-old man with a painful pulsatile mass approximately 8 cm in diameter in the right buttock was diagnosed using angiography as having a complete unilateral persistent sciatic artery aneurysm. The lesion was obliterated by proximal and distal ligation of the sciatic artery at the pelvis and the adductor magnus canal. A femoropopliteal bypass was performed with inverted autologous saphenous vein. The residual mass was subsequently drained because of persistent symptoms. Postoperative recovery was good.

Aneurysm↗
PubMed1993

Early open mitral commissurotomy: long-term results.

It has frequently been suggested that early mitral commissurotomy could improve long-term results in patients with severe mitral stenosis. However, the real advantages of this procedure have yet to be demonstrated. To evaluate this hypothesis, we retrospectively studied 397 patients who underwent operation for mitral stenosis in our unit between 1978 and 1988. Forty of these patients (group I) fulfilled the criteria for early mitral commissurotomy: being young (average age 33 years), being asymptomatic or showing few symptoms, and being in sinus rhythm. The remaining 357 patients who underwent operation during the same period of time served as control (group II). Mitral valve replacement (p < 0.05) and associated tricuspid annuloplasty (p < 0.05) occurred less frequently in patients from group I than it did in patients from group II. Survival after 11 years for patients with early mitral commissurotomy was 100%, 90% of whom were in functional class I, were in sinus rhythm, and were receiving no medication whatsoever. Ninety-six percent of these patients were free of complications after 11 years, compared with 73% of patients in group II (p < 0.05). In our opinion, these results support the use of early mitral commissurotomy for young patients in sinus rhythm, who are symptom free, who are and who have a mitral valve area is 1.3 cm2 or less.

Adolescent↗
PubMed1993

[Orthotopic heart transplant. Study of early morbimortality (< or = 30 days). Experience at the Reina Sofía Hospital (Córdoba)].

From may 1986 to december 1991, we have performed 90 heart transplantation in the Hospital "Reina Sofía" from Córdoba. In the present study we analyze the early morbidity and mortality in a retrospective study on complications and factors determining its incidence. Seventy patients were male (86%) and 13 female (14%). Age ranged from 12 and 65 years. The 31% of patients needed in pharmacological support before transplantation, 15 of them were operated in a emergency situation because of cardiogenic shock. The pulmonary resistances oscillated between 0.5 and 8.7 units/m2 (Wood) (mean 2.5 +/- 1.4 units/m2). The mean time of ischaemia was 136 +/- 38 minutes (range 5-255 min). Hospital mortality (< or = 30 days) was 8.8% (8/90). No predictive factors from donor and recipient were found. Three main influences on complications were analyzed: a) influence of myocardial temperature, b) role of hematic cardioplegia, and c) usefulness of Aprotinin. Eighteen patients (20%) developed severe bradyarrhythmia needing a pacemaker in the post-operative period. We found a significant relationship with myocardial temperature (4.3 +/- 2.1 vs 6.2 +/- 2.6; p < 0.05) and transport solution temperature (5.8 +/- 2.3 vs 7.3 +/- 1.9; p < 0.05). No significant influence was found on the time of ischaemia, previous heart disease, previous treatment with Amiodarona, clinical condition, etc.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Myocardial revascularization and complete correction of tetralogy of Fallot in an adult. A case report].

The case is reported of a 62 year-old male having a clinical history of grade II dyspnoea from 9 year ago and recently showing grade II angina. He had presented mild cyanosis. Suspecting the existence of coronary arteriosclerosis, and with the clinical diagnosis of tetralogy of Fallot based particularly on two-dimensional and M-mode echocardiography, and angio-hemodynamic study was made which confirmed the presence of congenital heart disease and also revealed significant coronary lesions of the circumflex and right coronary arteries. The patient underwent surgery which involved complete correction of the tetralogy of Fallot and the placing of two aortocoronary grafts onto the circumflex and right coronary arteries. Favorable progress was noted both immediately after operation and 6 months later. Although cases have been described of Fallot disease associated with acute myocardial infarction, we believe that this is the first time a patient has undergone myocardial revascularization at the same time as undergoing complete correction of the congenital heart disease.

Coronary Artery Bypass↗
PubMed1990

Aberrant right subclavian artery associated with common carotid trunk. A rare cause of vascular ring.

We have reviewed four cases of incomplete vascular rings caused by the presence of a common carotid trunk from which arose both carotid arteries associated with an aberrant right subclavian artery. The patients were aged between 3 and 9 months. All patients presented with recurrent respiratory tract infections. Three patients showed signs of malnutrition and failure to thrive caused by episodes of bronchial aspiration from extrinsic compression of the oesophagus. One patient presented with dyspnoea induced by feeding and another had stridor. A common carotid trunk associated with an aberrant subclavian artery was confirmed in all cases. No other associated anomaly was observed in any patient. Ligature and section of the anomalous right subclavian artery was performed in all patients. The low incidence of this type of vascular ring, its physiopathological mechanism and surgical management are discussed.

Carotid Arteries↗
PubMed1990

A comparison of repair and replacement for mitral stenosis with partially calcified valve.

From January 1978 to December 1987 we operated on 135 patients with calcified mitral stenosis. In 60 patients a conservative operation was performed (group I). Nine patients required mitral annuloplasty associated with the commissurotomy. The other 75 patients underwent mitral valve replacement (group II). In 37 patients a mechanical prosthesis was used and in 38 a biologic one. The patients given mitral valve replacement had a more heavily calcified valve than those undergoing a conservative procedure. Twenty-one patients (12 from group I and 13 from group II) required associated tricuspid annuloplasty. The mean follow-up time was 69.1 months (1 months to 10 years). There were no significant differences between the two groups in terms of operative death (0% and 4%, respectively), postoperative functional class, actuarial survival rate at 10 years (84% and 96%, respectively), and probability of freedom from thromboemboli at 10 years (98% and 96%, respectively). However, the probability of freedom from reoperation at 10 years significantly favored the conservative surgery group (84% and 69%, respectively, p less than 0.01). Finally, the probability of freedom from complications at 10 years was also significantly higher in the conservative surgery group (82% and 64%, respectively, p less than 0.005). Because of these results we believe that conservative surgery is, at present, a better alternative than mitral valve replacement for patients with partially calcified mitral stenosis.

Actuarial Analysis↗
PubMedDate not supplied

Pacing requirements after orthotopic heart transplantation: incidence and related factors.

To assess the incidence of severe bradyarrhythmia and pacing requirements after orthotopic heart transplantation, as well as the possible causal mechanisms, we have reviewed our experience on 52 consecutive transplant patients. The overall incidence of bradyarrhythmia requiring pacing for at least 24 hours after transplantation was 27% (14 patients). The conditions of three of them required pacing for less than 1 week; the conditions of the other 11 patients (21%) required pacing for more than 1 week. Normal sinus rhythm resumed in all but four patients within 3 weeks; a permanent pacemaker was implanted in these four patients (7.6% of all 52 patients and 28% of patients requiring temporary pacing). Late complete heart block associated with acute rejection developed in two patients whose conditions required implantation of a permanent pacemaker. The age and sex of the recipient and donor were similar for patients with or without bradyarrhythmia. The percentage of patients with or without bradyarrhythmias taking amiodarone before transplantation (57% and 46%, respectively), total ischemic time (133 +/- 33 and 123 +/- 37 minutes, respectively), and cardiopulmonary bypass time (117 +/- 17 and 132 +/- 65 minutes, respectively) were not significantly different for either group of patients. The initial temperature of cardioplegic solution for organ storage and the preimplantation myocardial temperature were, however, significantly lower in patients whose conditions required pacing immediately after transplantation than in those whose conditions did not require pacing (5.3 +/- 1.7 degrees C versus 6.5 +/- 1.5 degrees C, p less than 0.05, and 3.9 +/- 1.6 degrees C versus 5.7 +/- 2.6 degrees C, p less than 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Pulmonary valve endocarditis during puerperal sepsis.

A case of pulmonary valve endocarditis caused by Staphylococcus aureus during puerperal sepsis in a female patient is reported. The M-mode and two dimensional echocardiographic finding are described. A review of the literature shows that this entity is rare. A large vegetation in the leaflet of the pulmonary valve was excised and the patient recovered after a full course of antibiotics.

Adult↗
PubMedDate not supplied

Post-coronariography dissection of the right coronary artery.

The case of a patient undergoing an emergency aortocoronary bypass to the right coronary artery after its acute dissection at coronariography is presented. Surgery was carried out two hours after the incident. After successful recovery and postoperative study, it was concluded that the main technical problem posed by this operation which was whether or not to ligate proximally the right coronary was satisfactorily solved by the initial decision not to ligate it.

Adult↗
PubMedDate not supplied

Preliminary experience with deflazacort, a new synthetic steroid with fewer undesirable side effects, in heart transplant patients.

Prednisone is widely used by most heart transplant units, despite its frequent side effects. Deflazacort, a new oral synthetic steroid with fewer side effects, has not been studied in heart transplant patients. Our initial experience with 26 heart transplant patients in whom prednisone was replaced by deflazacort at 11 +/- 11 months after transplantation is reported. After the switch to deflazacort, a significant decreased was noted in glycemia, total cholesterol, and LDL-cholesterol (p < 0.001). No difference was noted in severity or frequency of rejection and infection between patients being treated with deflazacort and another 26 patients who continued to be treated with prednisone over a comparable period of time after transplantation.

Adult↗