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Biomedical subjects

M Almeida

Publications and source records attributed to M Almeida.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Implantable cardioverter-defibrillators in patients resuscitated from sudden death and in patients with sustained refractory ventricular tachycardia].

OBJECTIVE: The aim of this study was to evaluate the results of our experience with implantable cardioverter-defibrillator therapy. PATIENT SELECTION: We treated with implantable cardioverter-defibrillator (ICD) 18 patients, 15 male and 3 female, mean age 51 years, ranging from 12 to 76 years, with life threatening ventricular arrhythmias. Eleven patients were resuscitated from cardiac arrest and seven had refractory ventricular tachycardia. The underlying condition was coronary artery disease in 12 patients, dilated cardiomyopathy in two, congenital long QT syndrome in one, mitral regurgitation in one and idiopathic in two patients. METHODS: All patients underwent cardiac catheterization and electrophysiological study before ICD implantation. In the first patient epicardial leads were used, but a transvenous approach was used in the remaining 17 patients. The device was implanted in an abdominal position in all patients. Defibrillation and pacing threshold tests were performed during the implantation procedure and whenever necessary. After implantation, patients were followed up in an outpatient basis, with evaluation of therapy efficacy and reprogramming of the device if required. The mean follow-up time was 16 months, ranging from 1 to 40 months. RESULTS: The implantation was successful and without complications in all patients. Defibrillation threshold was considered within normal range, with an electrode impedance ranging from 40 to 65 Ohms. During the follow-up period no deaths occurred, 8 patients (44%) had episodes of VT or VF that were successfully treated, with shock in six patients, with antitachycardia pacing in one and with both modalities in another patient. Inappropriate shocks were observed in three patients (16%). The device was reprogrammed in five patients. CONCLUSIONS: Our experience with implantable ICD in patients who survived cardiac arrest or with refractory VT has shown a low surgical risk with no mortality. The incidence of ICD discharges was high, with a satisfactory efficacy rate and the number of inappropriate shocks was acceptable. The careful patient selection made possible a good cost/benefit relation.

Adolescent↗
PubMed1996

[The radiofrequency catheter ablation of ventricular tachycardia].

OBJECTIVE: The aim of this study was to evaluate our results of radiofrequency catheter ablation (RFCA) of ventricular tachycardia. PATIENT SELECTION: We treated with RFCA nine patients, six male and three female, mean age 36 +/- 12 years with ventricular tachycardia (VT), who fulfilled the following criteria; 1) recurrent VT; 2) resistant fo medical therapy despite the use of more than one antiarrhythmic drug; 3) inducible by programmed ventricular stimulation; 4) hemodynamically well tolerated. The VT etiology was coronary artery disease (CAD) in three patients, dilated cardiomyopathy in one, right ventricular dysplasia in one and it was idiopathic in four (being fascicular in three and catecholaminergic right ventricular outflow tract VT in one). METHODS: The RFCA was performed under antiarrhythmic medication. The adequate ablation site was obtained by mapping of the VT, looking for the earliest ventricular activation, identification of isolated mid-diastolic potentials during sinus rhythm or presystolic during VT, good pace mapping (at least 10 of the 12 standard ECG leads), and high frequency short duration spikes, the so called P potentials in fascicular VT. Primary success achieved when occurred termination of VT during application of RF energy and/or VT was no longer inducible by programmed stimulation with the same stimulation protocol. RESULTS: Global primary success rate was 89%, being 100% in idiopathic VT, and 80% in VT associated with structural heart disease. In a follow-up period of 12 +/- 14 months all patients were alive, 75% free of VT in the idiopathic VT group; and 50% in patients with structural heart disease. One of these patients underwent cardioverter defibrillator implantation to treat a fast VT with a new morphology not treated by ablation, and the other two had VT modification with a significant reduction in the number of episodes. CONCLUSIONS: Radiofrequency catheter ablation of VT has shown a good success rate, and it is a valuable alternative in patients with hemodynamically tolerable VT, refractory to drug treatment, highly symptomatic and without surgical indication. In cases of idiopathic VT we had a high rate success and we think that RFCA will probably become the primary indication in symptomatic patients.

Adult↗
PubMed1996

Autocrine secretion of osteopontin by vascular smooth muscle cells regulates their adhesion to collagen gels.

Osteopontin (OPN) is a secreted protein postulated to facilitate vascular smooth muscle cell (VSMC) adhesion and migration. Rat aortic VSMC lines were isolated after infection with recombinant retroviruses harboring OPN sense and antisense constructs. All lines grew normally in monolayer culture. On three-dimensional collagen gels, normal VSMCs and lines containing sense constructs (n=15) or empty vector (n=10) attached to gel and invaded the matrix. Four of five antisense clones did not adhere or invade. Antisense clones had lower OPN levels after stimulation with angiotensin II than sense clones or clones containing the empty vector (antisense, 257+/-102 ng/ml; sense, 473+/-104; vector, 434+/-66). Non-adhering antisense clones had lower mean OPN levels after angiotensin II stimulation (161+/-47 ng/ml) than sense or antisense lines with normal adhesion (486+/-63 ng/ml). The ability to adhere correlated with OPN levels >250 ng/ml. Adhesion and invasion were fully restored with addition of 100 to 200 ng/ml of exogenous OPN and were inhibited in normal VSMCs by incubation with 1 microgram/ml anti-OPN antibody. The autocrine secretion of OPN appears to play an important role in VSMC adhesion, spreading, and invasion.

Animals↗
PubMed1996

[Exertion syncopal crisis in the young, associated with idiopathic long QT syndrome].

The cases of two young patients with repetitive syncopal attacks due to idiopathic long QT syndrome (ILQTS) are reported. Both had been primarily misdiagnosed for seizures. In one of the cases the QT interval in the ECG at rest was normal. The same patient had a previous episode of cardiac arrest with ventricular fibrillation. The treadmill stress test was of great value, revealing polymorphic ventricular tachycardia induced by exercise, and evaluating the efficacy of beta-blocking therapy in the follow-up. The ILQTS should be considered a possible etiology in any patient presenting with new onset seizures, especially in the young. The treatments were different in both cases. In the first one, the treatment with nadolol (100 mg od) revealed to be very effective with total remission of symptoms. The treadmill stress test performed 15 days after the beginning of treatment did not show any ventricular arrhythmias, and it was assumed that the patient was effectively protected against ventricular arrhythmias. After 4.5 months of follow up, no syncopal episodes occurred. In the second case due to young age, the frequency, and the severity of the attacks (cardiac arrest with ventricular fibrillation), and the inefficacy of beta-adrenergic-blocking agents, the implantable cardioversor-defibrillator was the treatment chosen, although the beta blocking therapy was maintained to reduce the number of arrhythmic events. The ILQTS is a rare anomaly related to sudden cardiac death. The ILQTS is characterised by the association of several distinctive electrocardiographic features, among which prolongation of the QT interval is the best known. Life-threatening arrhythmia occurs usually under conditions of physical or psychological stress. Relatively effective therapies do exist and are represented by antiadrenergic interventions: beta-adrenergic-blocking agents are the treatment of choice. When they fail, left sympathetic denervation or the automatic implantable cardioversor-defibrillator have also proved to be effective.

Adult↗
PubMed1996

[Infectious endocarditis caused by Q fever. Apropos of a clinical case].

Endocarditis is a rare, but some times fatal, complication of Q fever. Its diagnosis is difficult and it is based on non-specific cardiac findings and a high title of phase I antibodies. The treatment is based on tetracyclines alone or in combination with cotrimoxazole, for long periods of time. The therapeutic efficacy is evaluated by the measurement of phase I antibodies, every three months. The relapses are frequent despite the long period of antibiotic therapy. We report what is probably the first case of Q fever prosthesis endocarditis in Portugal, as a complication following an acute episode of Q fever.

Adult↗
PubMed1996

[Atypical fibrous histiocytoma of the seminal vesicle].

OBJECTIVES: To describe a rare case of fibrous histiocytoma of the seminal vesicles. METHODS: A tumor occupying the entire hypogastrium, extending beyond the umbilical region were the only remarkable findings in our 47-year-old male patient that prompted us to perform complementary studies such as US, contrast-enhanced radiological evaluation (urography, cystography, colon enema and intestinal transit time) and laparoscopy that disclosed an extraperitoneal tumor with no precise location. A large tumor involving the seminal vesicles was found at surgery and resected. The histological analyses disclosed an atypical fibrous histiocytoma of the seminal vesicles. RESULTS: Patient outcome was satisfactory. CONCLUSIONS: Because tumors of the seminal vesicles are uncommon, it is practically impossible to diagnose this tumor type preoperatively.

Genital Neoplasms, Male↗
PubMed1996

[Experience with dl-sotalol in the treatment of supraventricular arrhythmia].

OBJECTIVES: To review the results of our experience with oral dl-sotalol for preventive treatment of supraventricular tachyarrhythmias (atrial fibrillation and paroxysmal supraventricular tachycardia). POPULATION: 51 patients, 28 female and 23 male, mean age 46.2 +/- 14.4 years, from outpatient arrhythmology clinics of our institution, with recurrent supraventricular tachyarrhythmias (atrial fibrillation in 24 patients and paroxysmal supraventricular tachycardia in 27). All the patients, but one, had normal left ventricular function. Dl-sotalol was first choice medication in only three patients. Previously 2 +/- 1.3 antiarrhythmic drugs had been used. METHODS: Retrospective evaluation of therapeutic response (number of clinical recurrences according to a semi-quantitative scale) and secondary effects of dl-sotalol during a minimum follow-up of 18 months. The mean daily dose was 205 +/- 90 mg (80 to 400 mg). RESULTS: In 37% of the patients there were no clinical recurrences of arrhythmia during follow-up. In 37% of the patients there was a significant reduction in recurrences. In 26% there was no change in the number of recurrences. There were no significant differences in response between patients with atrial fibrillation and those with paroxysmal supraventricular tachycardia. Secondary effects occurred in 16% of the patients: symptomatic bradycardia, asthma or sexual dysfunction. No patient had heart failure, torsades de pointes, syncope or death. CONCLUSIONS: From our experience, DL-sotalol seems to be a good therapeutic alternative for the preventive treatment of supraventricular tachyarrhythmias, with a low risk in patients with good ventricular function.

Adult↗
PubMed1995

Osteopontin expression in cardiovascular diseases.

Adhesive interactions are recognized requirements for cellular proliferation, migration and differentiation during normal morphogenesis as well as disease. By differential cloning, osteopontin was identified as an adhesive protein upregulated during vascular remodeling and neointima formation in both rat models and human vascular diseases including atherosclerosis and restenosis. In functional studies, purified osteopontin promoted adhesion, focal contact formation, and migration of vascular smooth muscle and endothelial cells. Utilizing neutralizing antibodies, three integrin-type receptors, alpha v beta 3, alpha v beta 1, and alpha v beta 5 were found to support cellular adhesion to osteopontin. In contrast, only cells containing the alpha v beta 3 integrin could migrate towards an osteopontin gradient, demonstrating for the first time that different functions of osteopontin are mediated via distinct receptors. These results suggest a model whereby osteopontin, via its integrin-type receptors, contributes to vascular remodeling during development and disease by facilitating smooth muscle migration and simultaneously promoting endothelial coverage of the affected area.

Angiotensin II↗
PubMed1994

Engulfment and killing capabilities of neutrophils and phagocytic splenic function in persons occupationally exposed to lead.

Phagocytosis and intracellular killing of Candida albicans and Candida pseudotropicalis by neutrophils as well as phagocytic splenic function from lead-exposed workers were studied. Two species of Candida were used since in individuals with myeloperoxidase deficiency neutrophils are unable to kill C. albicans, whereas C. pseudotropicalis can be effectively lysed. Phagocytosis with both antigens and phagocytic splenic function were normal in all the workers studied. However, lytic activity towards C. albicans, but not C. pseudotropicalis was impaired. This defect was observed in lead-exposed workers with blood lead levels and urinary delta-aminolevulinic acid (ALA-U) concentrations in the "safe" (below 60 micrograms/dl and 6 mg/l, respectively) and toxic ranges. An impaired ability to kill C. albicans suggests that lead exposure may lead to a myeloperoxidase deficiency. With the exception of blood lead levels and ALA-U concentrations, there was no correlation between any of the other parameters examined.

Adolescent↗
PubMed1994

Osteopontin promotes vascular cell adhesion and spreading and is chemotactic for smooth muscle cells in vitro.

Osteopontin is an Arg-Gly-Asp-containing acidic phosphoprotein recently shown to be upregulated in vascular smooth muscle during rat arterial neointima formation and in human atherosclerotic plaques. Functional studies showed that osteopontin promoted adhesion of both cultured aortic endothelial cells and aortic smooth muscle cells. Adhesion of vascular cells to osteopontin was dose dependent and half maximal when solutions containing 7 and 30 nmol/L osteopontin were used to coat wells for endothelial and smooth muscle cells, respectively. Smooth muscle cells adherent to osteopontin were spread after 60 minutes, whereas endothelial cells remained round, although flattened, at this time point but were spread at 90 minutes. Cell spreading on osteopontin was accompanied by the formation of focal adhesion plaques. A newly developed anti-osteopontin antibody completely inhibited adhesion of both cell types to osteopontin but not to fibronectin or vitronectin. In addition, the peptide GRGDSP blocked adhesion to osteopontin, suggesting that integrins mediate Arg-Gly-Asp-dependent adhesion. Indeed, an antibody against the alpha v beta 3 integrin neutralized adhesion of both endothelium and smooth muscle cells to osteopontin by approximately 50%, demonstrating that alpha v beta 3 is one osteopontin receptor on vascular cells. Osteopontin also promoted the migration of smooth muscle cells in a Boyden-type chamber, with half-maximal effects observed at 77 nmol/L osteopontin. Checkerboard analysis demonstrated that this stimulus was chemotactic in nature. Our findings suggest that osteopontin may be functionally important as an adhesive and chemotactic molecule for vascular cells, particularly when levels of osteopontin are dramatically increased, as is the case after arterial angioplasty and in atherosclerotic plaques.

Animals↗
PubMed1994

Immunoglobulin levels and cellular immune function in lead exposed workers.

The immunological status of lead acid battery workers with blood lead levels and urinary delta-aminolevulinic acid (ALA-U) concentrations ranging from safe to toxic levels has been examined and compared with those of non-exposed, age and sex matched controls. No differences in the serum concentrations of IgG, IgA and IgM between the populations were observed and there existed no correlation between blood lead level or ALA-U concentrations and serum immunoglobulin levels. In addition assessment was made of the capacity of peripheral blood mononuclear cells to respond to the mitogen phytohaemagglutinin (PHA), a correlate of T cell function. As before, there was no difference between exposed and control populations and no correlation between reactivity and blood lead concentration. Our data suggest that chronic exposure to lead fail to compromise lymphocyte function in man.

Aminolevulinic Acid↗
PubMed1994

Fine-needle aspiration biopsy cytology of myositis ossificans.

Increased utilization of fine-needle aspiration cytology to better define mass lesions before surgical excision can occasionally expose a cytologically worrisome yet biologically benign proliferative process. Such a proliferation may mimic a malignant neoplasm but is actually benign. Because of its limited exposure in the literature, we describe the cytopathology of two cases of myositis ossificans obtained by the fine-needle aspiration biopsy technique. Both lesions occurred in adolescents. One involved the deep muscle of the thigh, whereas the other was a superficial lesion of the anterior abdominal subcutaneous fat. In both instances a benign entity was favored, but in one case sarcoma could not be absolutely excluded by fine-needle aspiration cytology. Follow-up surgical excision in one case, and incisional biopsy in the other confirmed the diagnosis of myositis ossificans (MO). The cytologic differential diagnosis of this lesion is discussed.

Adolescent↗
PubMed1993

Defective neutrophil function in workers occupationally exposed to lead.

Chemotaxis and nitroblue tetrazolium reduction were measured in peripheral blood neutrophils of workers occupationally exposed to lead. These two neutrophil functions were significantly reduced, as compared to controls, even in those workers with blood lead levels and urinary delta-aminolevulinic acid (ALA-U) concentrations below the currently accepted biological limit values of 60 micrograms/dl and 6 mg/l, respectively. The immunosuppressive effects of relatively low level lead absorption suggests that immune dysfunction may be a sensitive indicator of lead exposure.

Adolescent↗
PubMed1993

Osteopontin is elevated during neointima formation in rat arteries and is a novel component of human atherosclerotic plaques.

In an earlier report, we used differential cloning to identify genes that might be critical in controlling arterial neointima formation (Giachelli, C., N. Bae, D. Lombardi, M. Majesky, and S. Schwartz. 1991. Biochem. Biophys. Res. Commun. 177:867-873). In this study, we sequenced the complete cDNA and conclusively identified one of these genes, 2B7, as rat osteopontin. Using immunochemistry and in situ hybridization, we found that medial smooth muscle cells (SMC) in uninjured arteries contained very low levels of osteopontin protein and mRNA. Injury to either the adult rat aorta or carotid artery using a balloon catheter initiated a qualitatively similar time-dependent increase in both osteopontin protein and mRNA in arterial SMC. Expression was transient and highly localized to neointimal SMC during the proliferative and migratory phases of arterial injury, suggesting a possible role for osteopontin in these processes. In vitro, basic fibroblast growth factor (bFGF), transforming growth factor-beta (TGF-beta), and angiotensin II (AII), all proteins implicated in the rat arterial injury response, elevated osteopontin expression in confluent vascular SMC. Finally, we found that osteopontin was a novel component of the human atherosclerotic plaque found most strikingly associated with calcified deposits. These data implicate osteopontin as a potentially important mediator of arterial neointima formation as well as dystrophic calcification that often accompanies this process.

Amino Acid Sequence↗