Search PubMed⌕ Search

Biomedical subjects

J Abreu

Publications and source records attributed to J Abreu.

At least 19 recordsLinked to original sources
PubMed2006

[Effects of nasal positive airway pressure treatment on oxidative stress in patients with sleep apnea-hypopnea syndrome].

OBJECTIVE: To analyze whether nasal continuous positive airway pressure (CPAP) reduces oxidative stress in patients with sleep apnea-hypopnea syndrome (SAHS). PATIENTS AND METHODS: Thirty-six patients with SAHS requiring nasal CPAP treatment and 10 controls in whom SAHS was ruled out were enrolled. Oxidative stress was evaluated by measuring plasma malondialdehyde (MDA) concentrations to assess lipid peroxidation at the beginning of the study and then again after a mean (SD) of 2.9 (0.6) months of nasal CPAP. Plasma MDA concentrations were determined by measuring thiobarbituric acid reactive substances. We controlled for the following factors known to influence oxidative stress: age, sex, use of vitamin supplements, smoking habit, body mass index (kg/m2), ischemic cardiopathy, hypertension, diabetes, and hypercholesterolemia. RESULTS: The mean age of patients with SAHS was 51.4 (9.9) years and the mean body mass index was 32.9 (5.3) kg/m2. Nasal CPAP was titrated to a mean pressure of 8.9 (3.4) cm H2O. The mean score on the Epworth sleepiness scale was 10.2 (4.3) before treatment and 4.2 (2.8) after treatment (P<.001). The apnea-hypopnea index decreased from 43.7 (22.6) before treatment to 4 (3.5) after treatment (P<.001). Mean MDA concentrations in patients with SAHS were 2.0 (1.1) micromol/mL before treatment and decreased significantly to 1.6 (.07) micromol/mL after treatment, whereas MDA concentrations remained unchanged in control subjects. CONCLUSIONS: Nasal CPAP treatment significantly reduced oxidative stress in patients with SAHS in our study.

Adult↗
PubMed2001

Molecular mechanisms of cell-cell signaling by the Spemann-Mangold organizer.

We review how studies on the first Spemann-Mangold organizer marker, the homeobox gene goosecoid, led to the discovery of secreted factors that pattern the vertebrate embryo. Microinjection of goosecoid mRNA formed secondary axes and recruited neighboring cells. These non-cell autonomous effects are mediated in part by the expression of secreted factors such as chordin, cerberus and Frzb-1. Unexpectedly, many of the molecules secreted by the Spemann-Mangold organizer turned out to be antagonists that bind growth factors in the extracellular space and prevent them from binding to their receptors. The case of chordin is reviewed in detail, for this molecule has provided biochemical insights into how patterning by Spemann's organizer can be regulated by diffusion and proteolytic control. The study of the BMP-binding repeats of Chordin, which are present in many extracellular proteins, may provide a new paradigm for how cell-cell signaling is regulated in the extracellular space not only in embryos, but also in adult tissues.

Amino Acid Sequence↗
PubMed2000

Long-term controlled trial of nocturnal nasal positive pressure ventilation in patients with severe COPD.

STUDY OBJECTIVES: To determine the 1-year efficacy of noninvasive positive pressure ventilation (NPPV) added to long-term oxygen therapy (LTOT) in patients with stable severe COPD. PATIENT SELECTION AND METHODS: We prospectively randomized 52 patients with severe COPD (FEV(1) < 45%) to either NPPV plus "standard care" (96% patients with LTOT) or to standard care alone (93% patients with LTOT). The outcomes measured included the following: rate of acute COPD exacerbations; hospital admissions; intubations; and mortality at 3 months, 6 months, and 12 months. The patients were also evaluated at 3 months and 6 months for dyspnea using the Medical Research Council and Borg scales, gas exchange, hematocrit, pulmonary function, cardiac function with echocardiogram, and neuropsychological performance. RESULTS: One-year survival was similar in both groups (78%). The number of acute exacerbations was similar at all time points in patients receiving NPPV, compared with control subjects. The number of hospital admissions was decreased at 3 months in the NPPV group (5% vs 15% of patients, p < 0.05), but this difference was not seen at 6 months (18% vs 19%, respectively). The only beneficial differences were observed in the Borg dyspnea rating, which dropped from 6 to 5 (p < 0.039), and in one of the neuropsychological tests (psychomotor coordination) for the NPPV group at 6 months. CONCLUSIONS: Our study indicates that over 1 year, NPPV does not affect the natural course of the disease and is of marginal benefit in outpatients with severe COPD who are in stable condition.

Acute Disease↗
PubMed2000

Cardiac output quantification by Doppler echocardiography in intensive care--limitations and validation.

UNLABELLED: Cardiac output (CO) quantification is primordial to the evaluation of patients with heart failure who are on tailored therapy and under invasive hemodynamic monitoring. Doppler echocardiography can be used to access CO noninvasively, but the concordance between its results and those obtained by invasive methods in paired measurements is still controversial. To our knowledge, no previous studies have assessed the clinical relevance of Doppler echocardiography for CO serial evaluation in patients submitted to tailored therapy. AIM: To evaluate the usefulness of echo-Doppler in the assessment of CO and quantification of changes in CO, compared to thermodilution, in patients with advanced heart failure under hemodynamic monitoring to guide tailored therapy. METHODS: In 20 patients (14 male, 62 +/- 14 years old, all in sinus rhythm), with dilated cardiomyopathy and NYHA IV, admitted to the intensive care unit (ICU), CO was simultaneously determined by Doppler echocardiography (dpCO) and thermodilution (tdCO) in three serial evaluations (overall 60). The dpCO was calculated by multiplying the aortic orifice area by the velocity-time integral of aortic continuous wave Doppler flow and by the heart rate. A difference between tdCO and dpCO of more than 20% was considered a major error. RESULTS: In the overall evaluations, dpCO systematically overestimates tdCO (p = 0.026). The correlation between tdCO and dpCO was 0.81, the mean difference between measurements was 0.40 +/- 0.61 l/min (mean -2SD = -1.62 mean +2SD = 0.81) and 19 (32%) major errors occurred. No significant difference was found between CO percentual variation values assessed by both methods, with a stronger correlation (r = 0.92-p = 0.014) compared to that found for absolute values. On using the dpCO/tdCO ratio in the first evaluation to correct subsequent dpCO, the correlation was fairly good (r = 0.96-p = 0.0002 versus corrected dpCO). The mean difference between paired measurements was significantly lower (0.12 +/- 0.28 l/min-mean 2SD = -0.44 mean +2SD = 0.67), and there were no errors. CONCLUSIONS: CO estimated by Doppler echocardiography has a good correlation with thermodilution although with a weak concordance between paired results in patients with dilated cardiomyopathy and advanced heart failure admitted to the ICU for tailored therapy. Our results with dpCO percentual change in repeated evaluations and with corrected dpCO value after a single simultaneous invasive determination suggest that Doppler echocardiography is a valid method for clinical purposes, allowing us to propose a reduction in the time period of invasive hemodynamic monitoring.

Adult↗
PubMed1999

[Isolated left anterior artery disease: angiographic features and clinical evolution of patients submitted to surgical myocardial revascularization or angioplasty].

The option for revascularization and the choice of intervention in isolated left anterior descending artery disease may be controversial. We decided to study retrospectively a group of revascularized patients (PTCA or surgery), with previous isolated LAD disease, to evaluate the angiographic features of LAD lesion, its contribution to the persistence of symptoms after revascularization and also to compare the occurrence of cardiac events in the two subgroups (PTCA and surgery). We studied 87 patients (mean age 57 +/- 10 years) submitted to myocardial revascularization (68 PTCA; 19 surgery), whose clinical evolution was followed for a mean period of 49 +/- 10 months (cardiac events: death, myocardial infarction, angina, heart failure, PTCA, surgery). We evaluated in cineangiography angiographic features of LAD lesions (degree of stenosis, lesion length and diameter, ectasia, luminal irregularity, ulcerated plaque, eccentricity, thrombus, calcification, type of lesion). On comparing angiographic features, we noted coronary lesions were longer in operated patients (p < 0.05) and a tendency for more complex lesions in this group (p = 0.08). After revascularization, 65% of PTCA patients and 26% of operated patients maintained angina (p < 0.01). The frequency of events was significantly higher in patients submitted to PTCA (84%) due to the greater occurrence of angina (65%). Sixteen percent PTCA were redilated and 6% operated whereas 11% of the surgical group were reoperated, without statistical difference regarding reintervention between the two groups. In the PTCA group, the greater frequency of angina and the necessity of a new PTCA could reflect restenosis. The disappearance of angina in operated patients may reflect probable patency of coronary bypass.

Aged↗
PubMed1999

[The semiquantitative evaluation of systemic vascular resistances in heart failure via an analysis of Doppler aortic flow].

UNLABELLED: In patients with advanced heart failure (HF) submitted to tailored therapy, monitoring of systemic vascular resistance (SVR) is essential to establish an adequate hemodynamic response, being one of the end-points to achieve SVR < 18 Wood U (WU). PURPOSE: To correlate SVR value with parameters derived from the analysis of echo-Doppler aortic flow in patients with HF on tailored therapy, in order to allow a non-invasive semiquantitative evaluation of this hemodynamic end-point. METHODS: In 13 patients with dilated cardiomyopathy (eight idiopathic, five ischemic) and advanced HF (mean age 60 +/- 10 years, 10 male, all in sinus rhythm, NYHA class IV), admitted in the ICU and submitted to tailored therapy, serial simultaneous hemodynamic and echocardiographic studies were performed (2 to 5 per patient, overall 43 evaluations). The following parameters derived from the analysis of continuous wave aortic Doppler flow were analysed: peak velocity, acceleration, deacceleration and ejection times, systolic time intervals ratio, mean acceleration, mean deacceleration, acceleration, deacceleration and overall systolic flow velocity time integrals. RESULTS: SVR ranged from 10.4 to 41.9 WU (mean = 21.7, SD = 6.9). A significant correlation was found only with mean deacceleration (MnDc)-r = -0.60. MnDc ranged from 362 to 1162 cm/s2 (mean = 667, SD = 188) and proved to be independent from heart rate, systolic, diastolic and mean blood pressure, capillary wedge pressure, cardiac output, cardiac index and ejection volume. MnDc < 700 cm.s2 occurred in 25/28 evaluations with SVR > 18 WU and only in 3/15 evaluations with SVR < 18 WU-p = 0.00003. A MnDc value < 700 cm.s2 showed sensitivity = 89%, specificity = 80%, and predictive value = 89% for SVR > 18 WU (Kappa index = 0.693). CONCLUSION: Mean deacceleration of aortic continuous wave flow is reliable for semiquantitative evaluation of systemic vascular resistance and can be particularly useful for patients with advanced heart failure submitted to tailored therapy.

Adult↗
PubMed1999

[The sinus venosus type of interatrial communication: its diagnosis by transesophageal echocardiography].

Transthoracic echocardiography has important limitations in the diagnosis of sinus venosus atrial septal defects in adults because of the posterior location of the defect. We review the role of transesophageal echocardiography in the diagnosis of this congenital heart disease in nine patients, as well as in the identification of associated abnormal pulmonary venous connections.

Adult↗
PubMed1999

[A pseudoaneurysm of the mitral-aortic intervalvular fibrosis after aortic valve replacement].

A 58-year-old male underwent a transesophageal echocardiogram for suspected aortic valve infective endocarditis, four years after surgery. The examination, performed with a multiplane probe, showed a pulsatile (systolic expansion) echo-free cavity in the intervalvular mitral-aortic region, communicating with the left ventricle outflow tract, with no signs of rupture to the left atrium or the aorta. These findings meet the criteria for the diagnosis of pseudoaneurysm of the mitral-aortic intervalvular fibrosa.

Aneurysm, False↗
PubMed1998

[Clinical manifestations and therapeutic of isolated infective endocarditis of the tricuspid valve].

We reviewed the records of patients admitted to our centre with the diagnosis of isolated tricuspid valve infective endocarditis and analysed the clinical presentation, etiopathogenic agent, echocardiographic features and therapeutic approach, namely the indication for cardiac surgery. Between 1988 and 1996, 11 cases of confirmed tricuspid valve endocarditis were identified, corresponding to 5% of the cases of endocarditis admitted to our centre in the same period. A predisposing factor was found in ten of the patients, half of them intravenous drug addicts and Staphylococcus aureus was the most frequent agent isolated. Fever and pleuro-pulmonary manifestations were predominant clinical features. Transthoracic echocardiography had a crucial role in the diagnosis and transesophageal echocardiography was important to characterize vegetations. Four patients underwent cardiac surgery, for persistent infection. In two cases, excision of the vegetations and ring annuloplasty was performed. In two patients not addicted to drugs, the tricuspid valve was replaced with a bioprosthesis, since the extension of the damage to the valve did not allow repair. One patient, with early endocarditis of a tricuspid bioprosthesis died before surgery was attempted.

Endocarditis, Bacterial↗
PubMed1998

[Biological prostheses in the tricuspid position. The immediate and follow-up results].

The results of bioprostheses in the tricuspid position were analysed in 42 patients. 79% were in NYHA class III-IV and 43% had previous cardiac surgery. Concomitant surgical procedures were performed in 86% of the cases. Surgical mortality was 14.3%. Mean follow-up was 54 +/- 31 months. Eight patients were reoperated (5.1%/patient/year), but only 3 for the tricuspid prosthesis. Four patients, with left-sided mechanical prostheses, had systemic thromboembolic events (3.8%/patient/year) and 3 on oral anticoagulation had major haemorrhage (2.8%/patient/year). Primary tricuspid valve dysfunction occurred in two patients (1.2%/patient/year). There were no cases of tricuspid valve thrombosis. For hospital survivors, 5 and 8 years survival was 91.4 +/- 10.3% and 76.2 +/- 10.4%, respectively. The only preoperative predictor of decreased survival was pulmonary artery systolic pressure > or = 50 mmHg. Tricuspid valve replacement with a bioprosthesis was usually performed in the set of multiple-valve operation, with previous cardiac surgery in a high percentage of patients, carrying a significant surgical mortality. However, the long-term survival and the low rate of events related to the tricuspid bioprosthesis favours its use, when conservative surgery is not feasible.

Actuarial Analysis↗
PubMed1997

[Mitral valve insufficiency caused by tendinous cord rupture and mitral valve aneurysm. Significance of the echocardiographic study].

Mitral valve aneurysm is a rare complication that may occur in a myxomatous valve. We report the case of a 73 year old male patient with severe mitral regurgitation and heart failure-class IV NYHA. Echocardiography showed perforation of an aneurysm of the anterior leaflet of the mitral valve associated with rupture of tendinous cords of the posterior mitral leaflet. Diagnosis was made by transthoracic echocardiography and confirmed by transesophageal echocardiography. The patient was urgently operated with success and a mitral valve prosthesis was implanted.

Aged↗
PubMed1995

[The QTc interval and its dispersion in hypertrophic myocardiopathy--its relation to complex ventricular arrhythmias and the effect of anti-arrhythmia agents].

UNLABELLED: The aim of the present study was to evaluate, in patients with hypertrophic cardiomyopathy (HCM): 1. The relation of rate corrected QT interval (QTc) and of QTc interlead variability (QTc dispersion) to complex ventricular arrhythmias (CVA); 2. The effects of amiodarone (Am), beta-blockers (beta B) and calcium antagonists (CA) on QTc and on QTc dispersion. Surface 12 leads ECG was analysed in 55 patients with HCM (39 +/- 12 years, 32 males). All patients were in sinus rhythm, without bundle branch block. Maximum (max), minimum (min) and mean QTc values were considered. QTc dispersion was calculated as: a) max QTc - min QTc (max-min); b) dispersion index (DI) = standard deviation of QTc/mean QTcx100. Patients groups were defined accordingly to: 1--the absence (group A1-35 patients) or the presence (group A2-20 patients) of CVA on 24 hours Holter monitoring; II--absence of cardioactive medication (group B1-20 patients) versus monotherapy with Am (group B3-10 patients), or beta B (group B4-15 patients), or CA (group B5-10 patients). Age, gender, type of HCM (asymmetric versus concentric) and echocardiographic fractional shortening were not different in the studied groups. RESULTS: [table: see text] CONCLUSIONS: 1. Maximum QTc interlead QTc dispersion are increased in patients with HCM that show CVA on Holter monitoring; 2. Amiodarone prolongs QTc but reduces QTc dispersion, while beta-blockers and calcium antagonists do not significantly change neither the duration nor the dispersion of ventricular repolarization.

Adrenergic beta-Antagonists↗
PubMed1995

[Emergency catheterization in a coronary intensive care unit. The diagnostic and therapeutic implications].

OBJECTIVE: to evaluate the diagnostic and therapeutic role of emergency hemodynamic studies, in the coronary intensive care (UCI). STUDY DESIGN: Retrospective study of--patients (P) submitted to emergency catheterization. PATIENTS: 183 P (152 M and 31 F), mean age 56 +/- 11.5 years, admitted to UCI of Hospital Santa Marta and who had cardiac catheterization performed, between October 88 and November 92. METHODS: Patient clinical files were reviewed. We considered the reasons for emergency cardiac catheterization; final diagnosis; complications in the first 24 hours; catheterization role in the therapeutic orientation. RESULTS: Reasons for hemodynamic study were: coronary artery disease (CAD) in 127 P (69%); aortic dissection in 33 P (18%); valvular disease in 19 P (10%) and other in 4 P (3%). Clinical diagnosis was confirmed in 92% and changed in 8% by hemodynamic study results. Left main coronary artery disease was diagnosed in 6.5% of CAD patients. Coronary artery disease was excluded in 5 P with previous CAD diagnosis, in 19 P with aortic dissection and in 11 valvular patients. 32% of P were sent to emergent surgery: 93% ascending aortic dissection and 20% of CAD, 76% of valvular disease. The hemodynamic study was decisive in the therapeutic option of myocardial revascularization in 77% of P with CAD: 39 emergent PTCA (31%), 13 primary (33%) and 14 P oriented to elective PTCA (11%); 26 emergent surgery and 19 P oriented to elective surgery (15%). The emergency cardiac catheterization mortality rate was 0.5%, and the morbidity 2.7%. CONCLUSIONS: The contribution of Hemodynamic Department to UCI was decisive in the diagnostic and therapeutic orientation of critical patients.

Adult↗