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Biomedical subjects

A C Carvalho

Publications and source records attributed to A C Carvalho.

At least 19 recordsLinked to original sources
PubMed2001

Acute precipitants of congestive heart failure exacerbations.

BACKGROUND: Few studies have prospectively and systematically explored the factors that acutely precipitate exacerbation of congestive heart failure (CHF) in patients with left ventricular dysfunction. Knowledge of such factors is important in designing measures to prevent deterioration of clinical status. The objective of this study was to prospectively describe the precipitants associated with exacerbation of CHF status in patients enrolled in the Randomized Evaluation of Strategies for Left Ventricular Dysfunction Pilot Study. METHODS: We conducted a 2-stage, multicenter, randomized trial in 768 patients with CHF who had an ejection fraction of less than 40%. Patients were randomly assigned to receive enalapril maleate, candesartan cilexetil, or both for 17 weeks, followed by randomization to receive metoprolol succinate or placebo for 26 weeks. Investigators systematically documented information on clinical presentation, management, and factors associated with the exacerbation for any episode of acute CHF during follow-up. RESULTS: A total of 323 episodes of worsening of CHF occurred in 180 patients during 43 weeks of follow-up; 143 patients required hospitalization, and 5 died. Factors implicated in worsening of CHF status included noncompliance with salt restriction (22%); other noncardiac causes (20%), notably pulmonary infectious processes; study medications (15%); use of antiarrhythmic agents in the past 48 hours (15%); arrhythmias (13%); calcium channel blockers (13%); and inappropriate reductions in CHF therapy (10%). CONCLUSIONS: A variety of factors, many of which are avoidable, are associated with exacerbation of CHF. Attention to these factors and patient education are important in the prevention of CHF deterioration.

Adrenergic beta-Antagonists↗
PubMed2001

Monitoring of intragraft and peripheral blood TIRC7 expression as a diagnostic tool for acute cardiac rejection in humans.

T-cell immune response cDNA 7 (TIRC7) is a recently described T-cell costimulatory molecule that exhibits a central role in T-cell activation in vitro and in vivo. The present study was undertaken to investigate association between intragraft and peripheral blood mononuclear cell (PBMC) TIRC7 mRNA levels and cardiac allograft rejection in humans. TIRC7 gene expression levels were determined by a quantitative-competitive reverse transcriptase-polymerase chain reaction (QC-RT-PCR) in endomyocardial biopsies and in PBMC from cardiac transplant recipients. Biopsies collected during rejection or up to 15 days before rejection showed heightened TIRC7 mRNA expression in comparison with biopsies without rejection. All prerejection and rejection biopsies showed TIRC7 mRNA upregulation, while this was present in only 30% of the biopsies without rejection. Regarding TIRC7 mRNA in PBMC, transplant recipients showed lower levels than healthy individuals and, in contrast to the results obtained in biopsies, the levels were lower during rejection than in rejection-free periods. In summary, TIRC7 mRNA expression levels increase in biopsies and decrease in peripheral blood during acute cardiac rejection. We conclude that intragraft detection of TIRC7 transcripts is a useful tool not only for the diagnosis but also for the prediction of acute heart allograft rejection episodes.

Gene Expression↗
PubMed2001

Cytokines and pediatric open heart surgery with cardiopulmonary bypass.

It is well known that, subsequent to cardiopulmonary bypass, and particularly in children, an inflammatory response within the body can often result in a characteristic syndrome. Recently, it has been suggested that this phenomenon is due to a systemic inflammatory response, with significant involvement of cytokines. With this in mind, we investigated the behavior of tumour necrosis factor-alpha and interleukin-6 during the operative and in the immediate postoperative period in a group of children submitted to open heart surgery. We investigated any possible relation between the levels of these cytokines in the serum and the length of cardiopulmonary bypass, with the serum levels of lactate, and with the extent of use of inotropic drugs in postoperative period. The cytokines were measured in samples withdrawn after induction of anesthesia, after 10 minutes of cardiopulmonary bypass, after re-establishment of circulation, and then 2 and 24 hours after the end of cardiopulmonary bypass. The levels of tumour necrosis factor-alpha and interleukin-6 increased between the beginning and at two hours of the end of cardiopulmonary bypass. There was no correlation between the levels of these cytokines in the serum and the length of cardiopulmonary bypass, although there was a positive relation between levels of interleukin-6 and lactate in samples withdrawn at two hours of the end of bypass, and the measured levels of the cytokines correlated with the extent of inotropic drugs employed in the postoperative period.

Cardiopulmonary Bypass↗
PubMed2001

Molecular characterization of invasive and noninvasive Campylobacter jejuni and Campylobacter coli isolates.

Campylobacter jejuni is one of the most common causes of bacterial diarrhea worldwide and is the primary bacterial cause of food-borne illness. Adherence to and invasion of epithelial cells are the most important pathogenic mechanisms of Campylobacter diarrhea. Molecular characterization of invasive and noninvasive Campylobacter isolates from children with diarrhea and symptom-free children was performed by random amplified polymorphic DNA techniques (RAPD). A distinct RAPD profile with a DNA band of 1.6 kb was observed significantly more frequently among invasive (63%) than among noninvasive (16%) Campylobacter isolates (P = 0.000005). The 1.6-kb band was named the invasion-associated marker (IAM). Using specifically designed primers, a fragment of 518 bp of the iam locus was amplified in 85% of invasive and 20% of noninvasive strains (P = 0.0000000). Molecular typing with a PCR-restriction fragment length polymorphism assay which amplified the entire iam locus showed a HindIII restriction fragment polymorphism pattern associated mainly with invasive strains. Although cluster analysis of the RAPD fingerprinting showed genetic diversity among strains, two main clusters were identified. Cluster I comprised significantly more pathogenic and invasive isolates, while cluster II grouped the majority of nonpathogenic, noninvasive isolates. These data indicate that most of the invasive Campylobacter strains could be differentiated from noninvasive isolates by RAPD analysis and PCR using specific primers that amplify a fragment of the iam locus.

Bacterial Proteins↗
PubMed2001

Is the number of microembolic signals related to neurologic outcome in coronary bypass surgery?

Coronary artery bypass surgery (CABG) without cardiopulmonary bypass (CPB) may potentially reduce the number of microembolic signals (MES) associated with aortic manipulation or generated by the pump circuit, resulting in a better neurologic outcome after surgery. Our aim was to compare the frequency of MES and neurologic complications in CABG with and without CPB. Twenty patients eligible to routine CABG without CPB were randomized to surgery with CPB and without CPB and continuously monitored by transcranial Doppler. Neurologic examination was performed in all patients before and after surgery. The two groups were similar with respect to demographics, risk factors, grade of aortic atheromatous disease and number of grafts. The frequency of MES in the nonCPB group was considerably lower than in CPB patients, however, we did not observe any change in the neurologic examination during the early postoperative period. Neurologic complications after CABG may be related to the size and composition of MES rather than to their absolute numbers. A large prospective multicentric randomized trial may help to elucidate this complex issue.

Aortic Diseases↗
PubMed2001

[Use of transesophageal echocardiography during implantation of aortic endoprosthesis (stent). Initial experience].

OBJECTIVE: To report the role played by transesophageal echocardiography during implantation of self-expanding aortic endoprostheses (stent) at a hemodynamics laboratory. METHODS: Thirteen patients underwent stent implantation in the descending thoracic aorta with the aid of transesophageal echocardiography during the entire procedure. Indications for stenting were as follows: 8 aortic dissections, 2 true aneurysms, 2 penetrating atherosclerotic ulcers, and 1 traumatic pseudoaneurysm. RESULTS: No complications resulting from the use of transesophageal echocardiography were observed. In 12 patients, the initial result was considered appropriate, with total or partial resolution of the major lesion confirmed by a posterior examination. In 1 patient, the procedure was suspended after transesophageal echocardiography and angiography showed that the proximal aortic diameter was inappropriate. Transesophageal echocardiography contributed to clarifying relevant points, such as aortic diameter, anatomic detail of the intimal lesion, and location and size of the communicating orifice. In addition, it facilitated placing the stent in the target lesion, reduced the time of exposure to radiation and the use of contrast medium, and provided rapid identification of intercurrent events, possibly reducing the total duration of the procedure. CONCLUSION: The use of transesophageal echocardiography during placement of aortic stents seems appropriate. The actual advantages of the procedure will be defined in a comparative prospective study.

Aorta, Thoracic↗
PubMed2001

Expression of CD40 ligand, interferon-gamma and Fas ligand genes in endomyocardial biopsies of human cardiac allografts: correlation with acute rejection.

The purpose of the present study was to investigate the expression (mRNA) of CD40 ligand (CD40L), interferon-gamma (IFN-gamma) and Fas ligand (FasL) genes in human cardiac allografts in relation to the occurrence of acute cardiac allograft rejection as well as its possible value in predicting acute rejection. The mRNA levels were determined by a semiquantitative reverse transcriptase-polymerase chain reaction method in 39 samples of endomyocardial biopsies obtained from 10 adult cardiac transplant recipients within the first six months after transplantation. Biopsies with ongoing acute rejection showed significantly higher CD40L, IFN-gamma and FasL mRNA expression than biopsies without rejection. The median values of mRNA expression in biopsies with and without rejection were 0.116 and zero for CD40L (P<0.003), 0.080 and zero for IFN-gamma (P<0.0009), and 0.156 and zero for FasL (P<0.002), respectively. In addition, the levels of IFN-gamma mRNA were significantly increased 7 to 15 days before the appearance of histological evidence of rejection (median of 0.086 in pre-rejection biopsies), i.e., they presented a predictive value. This study provides further evidence of heightened expression of immune activation genes during rejection and shows that some of these markers may present predictive value for the occurrence of acute rejection.

Acute Disease↗
PubMed2001

Conventional and conventional plus modified ultrafiltration during cardiac surgery in high-risk congenital heart disease.

BACKGROUND: This prospective nonrandomized study is the critical assessment of conventional ultrafiltration (CUF) and modified ultrafiltration (MUF) techniques and their efficiency in congenital heart disease surgeries. Use of cardiopulmonary bypass (CPB) in children is associated with body water retention as a consequence of prime volume and systemic inflammatory reaction. The CUF during CPB has reduced body water excess and the MUF after CPB, removes inflammatory mediators, improves hemodynamic performance, and decreases transfusion requirements. METHODS: Forty-one patients, aged 9 to 36 months, submitted to surgical correction for cardiac defects, using CPB, were divided into 2 similar groups: CUF (21 patients) operated between 1996-1997 were ultrafiltered during CPB, and CUF+MUF, (20 patients) operated between 1997-1998 and ultrafiltered during and after CPB. Postoperative duration of ventilator support, pediatric intensive care unit stay (PICU), hospital stay of the groups with and without preoperative pulmonary hypertension (PH), as well as transfusion requirement, hematocrit and platelet counts were compared. RESULTS: There were no technical complications and a significant ultrafiltrate in the CUF+MUF group was observed as compared to the CUF group. No significant differences were observed between the CUF and CUF+MUF groups regarding ventilatory support, PICU stay and hospital stay. Requirements for red cell transfusion, Ht and platelet counts were not statistically different. CONCLUSIONS: CUF and CUF+MUF were safe and efficient methods for patient stabilization independent of diagnosis and complexity of surgery. Future clinical evaluation should address a larger population of patients to research the different variables.

Algorithms↗
PubMed2000

Reconstruction of the pulmonary valve and outflow tract with bicuspid prosthesis in tetralogy of Fallot.

BACKGROUND: Right ventricular outflow tract and pulmonary valve implant in patients with tetralogy of Fallot may be required to avoid late postoperative right ventricular impairment. The use of porcine bicuspid prosthesis might be a technical alternative, although comprehensive studies on the long-term use of these prostheses are not available. METHODS: Sixty-three patients (aged 5 months to 34 years; mean, 6 years) with tetralogy of Fallot and pulmonary hypoplasia underwent surgical repair and enlargement of the right ventricular outflow using preserved porcine pulmonary bicuspid prostheses. Fifty-two patients (82.5%) were followed and underwent clinical evaluation and serial Doppler echocardiography. The first 15 patients (29.4%), with ages ranging from 5 to 16 years (mean, 8.2 years) and postoperative follow-up of 48 to 87 months (mean, 65.1 months) underwent hemodynamic and cineangiographic evaluations. RESULTS: There were 11 deaths (17.4%) in the early postoperative period. Of the 52 surviving patients (82.5%), 51 (80.9%) were followed for 1 to 87 months (mean, 42.0 months). Four patients (7.6%) had additional treatment. Of the 15 patients (29.1%) undergoing hemodynamic evaluation, 9 (60%), had mild valvular pulmonary insufficiency and 6 (40%) had moderate insufficiency. Only the right ventricle-to-pulmonary artery pressure gradients and the right ventricular ejection fraction showed statistically significant differences between groups. Right ventricular dimension, although increased in all patients, did not show statistically significant differences. CONCLUSIONS: Right ventricular outflow tract and pulmonary valve repair in patients with tetralogy of Fallot using a bicuspid porcine pulmonary prosthesis is a simple, reliable procedure with good results in postoperative medium term follow-up.

Adolescent↗
PubMed2000

Right coronary artery fistula with congestive heart failure in the neonate. Doppler echocardiographic diagnosis and closure with detachable balloon.

We report here a case of coronary artery fistula in a neonate with clinical signs of heart failure. The electrocardiogram showed signs of left ventricular hypertrophy and diffuse alterations in ventricular repolarization. Chest X-ray showed an enlargement of the cardiac silhouette with an increase in pulmonary flow. After echocardiographic diagnosis and angiographic confirmation, closure of the fistulous trajectory was performed with a detachable balloon with an early and late successful outcome.

Arterio-Arterial Fistula↗
PubMed2000

Association of pulmonary atresia with intact ventricular septum and aortic valve stenosis. Prenatal diagnosis.

A rare association of pulmonary atresia with an intact septum was diagnosed through echocardiography in a fetus 32 weeks of gestational age. The diagnosis was later confirmed by echocardiography of the newborn infant and further on autopsy. The aortic valve was bicuspid with a pressure gradient of 81 mmHg, and the right ventricle was hypoplastic, as were the pulmonary trunk and arteries, and the blood flow was totally dependent on the ductus arteriosus.

Adult↗
PubMed2000

Structural and functional characteristics of rat hearts with and without myocardial infarct. Initial experience with Doppler echocardiography.

OBJECTIVE: To assess by Doppler echocardiography the structural and functional alterations of rat heart with surgical induced extensive myocardial infarction. METHODS: Five weeks after surgical ligature of the left coronary artery, 38 Wistar-EPM rats of both sexes, 10 of them with extensive infarction, undergone anatomical and functional evaluation by Doppler echocardiography and then euthanized for anatomopathological analysis. RESULTS: Echocardiography was 100% sensible and specific to anatomopathological confirmed extensive miocardial infarction. Extensive infarction lead to dilatation of left ventricle (diastolic diameter: 0.89 cm vs.0.64 cm; systolic: 0. 72 cm vs. 0.33 cm) and left atrium (0.55 cm vs. 0.33 cm); thinning of left ventricular anterior wall (systolic: 0.14 cm vs. 0.23 cm, diastolic: 0.11 cm vs. 0.14 cm); increased mitral E/ A wave relation (6.45 vs. 1.95). Signals of increased end diastolic ventricle pressure, B point in mitral valve tracing in 62.5% and signs of pulmonary hypertension straightening of pulmonary valve (90%) and notching of pulmonary systolic flow (60%) were observed in animals with extensive infarction. CONCLUSION: Doppler echocardiography has a high sensitivity and specificity for detection of chronic extensive infarction. Extensive infarction caused dilatation of left cardiac chambers and showed in Doppler signals of increased end diastolic left ventricular pressure and pulmonary artery pressure.

Animal Diseases↗
PubMed2000

Multiple arterial anomalies in the newborn infant. Echocardiographic and angiographic diagnosis.

Multiple arterial anomalies characterized by tortuosity and rolling of the pulmonary arteries and aorta were diagnosed on echocardiography in an asymptomatic newborn infant with a phenotype suggesting Ehlers-Danlos syndrome. These changes were later confirmed on angiography, which also showed peripheral vascular abnormalities. The electrocardiogram showed a probable hemiblock of the left anterosuperior branch, and the chest x-ray showed an excavated pulmonary trunk with normal pulmonary flow.

Abnormalities, Multiple↗
PubMed2000

Gap junctions in the cardiovascular and immune systems.

Gap junctions are clusters of intercellular channels directly connecting the cytoplasm of adjacent cells. These channels are formed by proteins named connexins and are present in all metazoan organisms where they serve diverse functions ranging from control of cell growth and differentiation to electric conduction in excitable tissues. In this overview we describe the presence of connexins in the cardiovascular and lympho-hematopoietic systems giving the reader a summary of the topics to be covered throughout this edition and a historical perspective of the discovery of gap junctions in the immune system.

Animals↗
PubMed2000

Gap junction modulation by extracellular signaling molecules: the thymus model.

Gap junctions are intercellular channels which connect adjacent cells and allow direct exchange of molecules of low molecular weight between them. Such a communication has been described as fundamental in many systems due to its importance in coordination, proliferation and differentiation. Recently, it has been shown that gap junctional intercellular communication (GJIC) can be modulated by several extracellular soluble factors such as classical hormones, neurotransmitters, interleukins, growth factors and some paracrine substances. Herein, we discuss some aspects of the general modulation of GJIC by extracellular messenger molecules and more particularly the regulation of such communication in the thymus gland. Additionally, we discuss recent data concerning the study of different neuropeptides and hormones in the modulation of GJIC in thymic epithelial cells. We also suggest that the thymus may be viewed as a model to study the modulation of gap junction communication by different extracellular messengers involved in non-classical circuits, since this organ is under bidirectional neuroimmunoendocrine control.

Bone Marrow Cells↗
PubMed2000

The value of echocardiography in the diagnosis and followup of rheumatic carditis in children and adolescents: a 2 year prospective study.

OBJECTIVE: To evaluate echocardiographic/Doppler findings in patients with rheumatic fever whether or not clinical manifestations of carditis were present, and the followup of these findings 24 months after the acute phase. METHODS: Twenty-two patients with rheumatic fever (13 boys, 9 girls, mean age 11.0 years) were evaluated at baseline (at diagnosis) and after 3 and 6 mo of disease. Eighteen patients were reevaluated 24 mo later. The assessment included physical and cardiac examination, electrocardiogram, chest radiography, and color ECHO/Doppler performed blindly by different investigators. The control group included 15 healthy children. RESULTS: We observed clinical carditis in 8 patients (36.4%): Group 1, all with ECHO abnormalities. We observed no clinical cardiac manifestations in 14 patients (Group 2), but 5 (35.7%) had positive ECHO/Doppler abnormalities that persisted at least 6 mo in followup assessments. Mitral and aortic were the most frequently involved valves. In Group 1 we observed normalization of the ECHO/Doppler in 3 patients, improvement in 2, no change in 2, and worsening in one. Twelve of 14 patients without clinical carditis were reevaluated, including the 5 patients with ECHO/Doppler abnormalities during the initial evaluations; normalization or improvement was observed in 2 patients, no change in 2, and worsening in one. We observed no ECHO/Doppler abnormalities in the control group. CONCLUSION: This blind prospective study suggests the existence of asymptomatic carditis in some patients with rheumatic fever and the role ECHO/Doppler investigation could play in diagnosis and followup.

Adolescent↗
PubMed1999

Cholinergic stimulation with pyridostigmine blunts the cardiac responses to mental stress.

Mental stress may induce myocardial ischemia and ventricular arrhythmia in patients with coronary artery disease, and cholinergic stimulation is a potential protective mechanism. The purpose of this study was to determine the effect of pyridostigmine bromide (PYR), a reversible cholinesterase inhibitor, on the cardiac responses to a mental stress challenge. Twelve healthy young volunteers were submitted to a mental stress test (arithmetic test) 2 hours after the oral administration of either placebo or PYR (45 mg) on two separate days, following a randomized crossover double-blind protocol. Heart rate was reduced after both placebo and PYR (p < 0.05), but the cardiac responses to the mental stress were lower with PYR (p < 0.05): mean RR interval (mean +/- SE)-placebo: 730 +/- 19 msec; PYR: 769 +/- 21 msec; Peak systolic pressure-placebo: 129 +/- 4 mmHg; PYR: 124 +/- 3 mmHg; Peak diastolic pressure-placebo: 92 +/- 3 mmHg; PYR: 89 +/- 4 mmHg; Mean rate-pressure product-placebo: 10,496 +/- 412 bpm x mmHg; PYR: 9,746 +/- 383 bpm x mmHg. In conclusion, 45 mg of pyridostigmine blunted the pressor and chronotropic responses to mental stress in healthy young subjects.

Aged↗