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Biomedical subjects

L Santos

Publications and source records attributed to L Santos.

At least 91 records · Page 5Linked to original sources
PubMed1996

[The radiofrequency catheter ablation of occult accessory atrioventricular pathways].

OBJECTIVE: The aim of this study was to evaluate our results of radiofrequency catheter ablation (RFCA) of concealed accessory atrioventricular pathways (CP). PATIENT SELECTION: We treated with RFCA 19 patients, with 21 CP, 10 men and 9 women, mean age 37 +/- 16 years, with supraventricular tachycardia (SVT) and absence of ventricular pre-excitation in the electrocardiogram (ECG). These patients comprised 50% of the patients who underwent RFCA for SVT and had no ventricular pre-excitation in the ECG. The diagnosis of CP was made by electrophysiologic study, based on the demonstration of a pathway capable of retrograde conduction only. METHODS: The RFCA was performed without antiarrhythmic drugs in the same session of the electrophysiologic diagnosis. The location of the CP site was obtained by catheter mapping, looking for the earliest atrial retrograde activation during tachycardia or ventricular pacing. RESULTS: The CP had a right-sided location in only 2 patients who had an incessant form of SVT, the CP in these patients exhibit decremental conduction--permanent junctional reciprocating tachycardia. In the other patients the CP was left-sided, lateral in 11 patients, posterior in 3, postero-septal in 3 and medial septal in one patient. In 9 patients there was a simultaneous ventricular activation in the his bundle electrogram and in the electrogram of the ablation site, suggesting partial anterograde penetration of the stimuli on the accessory pathway. Success criteria were achieved in 18 patients (95%) corresponding to 20 CP. CONCLUSIONS: The prevalence of CP in the presence of SVT without ventricular pre-excitation is high, almost all left-sided. The CP displays eccentric atrial activation during SVT. It is possible that CP are capable of partial anterograde conduction as well. The success rate of RFCA is high.

Adolescent↗
PubMed1996

[Orthotopic hepatic transplant in chronic hepatopathy of alcoholic origin].

Liver transplantation for alcoholic cirrhosis remains controversial at some transplantation centers. We compared resource utilization and outcome in alcoholic and non-alcoholic cirrhotic patients undergoing liver transplantation. From April 1990 to November 1994, 60 patients received orthotopic liver transplants for end-stage alcoholic liver disease, and 119 transplants were performed in 103 patients for non-alcoholic liver disease. No significant differences were noted in resource utilization of the variables examined. The outcome of liver transplantation (early graft function, frequency of sepsis, incidence of rejection, renal function, arterial hypertension...) was equivalent or better in alcoholic patients. Postoperative mortality was higher in non-alcoholic population (25.2% vs 16.7%). One-year and three year actuarial survival was not significantly different, but it was higher in the alcoholic group (77% vs 67% and 74% vs 64% respectively). The recurrence rate of alcohol in take has been 9.09%, with most patients drinking only socially. We conclude that liver transplantation for end-stage alcohol-related cirrhosis provides excellent results and resource utilization appears to be equivalent to that for patients undergoing transplantation for non-alcohol-related cirrhosis.

Female↗
PubMed1996

Ten basic World-Wide Web sites for Florida physicians.

The Internet is a rapidly growing information resource for rapid publication and access to information. While it has attracted a certain mystique and is undoubtedly attractive as an information source, its rapid and chaotic growth mitigates against ease of use for novices. The authors-all associated with health-care providers in the Dade/Broward market-offer the novice user their best assessment for initial Web sites to explore for health care information, and general guidance on using Internet search engines to direct effective searches.

Computer Communication Networks↗
PubMed1995

[The evolution of the arterial pressure during a stress test in patients with hypertrophic myocardiopathy].

OBJECTIVES: To study the exercise blood pressure response in patients with hypertrophic cardiomyopathy (HC) and its relationship with sudden death. DESIGN: Retrospective study. POPULATION: We studied 51 patients (P) with HC: 18 women and 33 men. Their average age was 45 +/- 14 years, with a mean follow-up of 55 +/- 37 months. METHODS: Every patient had been subjected to a treadmill stress-test, a 24-hour Holter monitoring and an echocardiographic examination. Particular emphasis was given to blood pressure increments (BPI) during stress-test, the existence of premature ventricular contractions with a frequency of 10 or more per hour (PVC > or = 10), the occurrence of couplets (C) and/or non-sustained ventricular tachycardia (NSVT) on a 24-hour Holter. Finally, the finding of systolic anterior motion (SAM) of the mitral valve, in the routine echocardiogram, was valued. RESULTS: Four patterns of BPI were identified: "1": normal evolution (27 P); "2": plateau type increment (16 P); "3": fall in blood pressure during exercise (6 P); "4": abnormal BPI during recovery (2 P). Two groups were considered: group N-normal BPI, group A-patients with abnormal blood pressure responses. There were no significant differences among therapeutic agents, between the two groups, when the stress-test was performed. SAM was found in 21 P. Only 8 P registered ventricular arrhythmias, half of them with NSVT. No statistical relations were found between BPI and P age, the presence of SAM, PVC > or = 10, C, or NSVT. We found 78% of P in group N in NYHA class I. In contrast, in group A only 46% were in class I (p = 0.04). Only one death, of non cardiac cause, occurred (group A). CONCLUSIONS: There is a large number of patients with HC and abnormal BPI. This is, seemingly, not influenced either by a dynamic left ventricular gradient or by ventricular ectopic beat occurrence. However, a relation appears to exist between the abnormal response and functional class, not explained by the usual (noninvasive) clinical tests.

Adult↗
PubMed1995

[Hypertensive colopathy: its endoscopic evaluation and evolution following a liver transplant].

In the last decade the association between intestinal vasculopathy and Portal Hypertension (PH) has been established on the basis of endoscopic, histological and histomorphometric examinations. We report the case of a patient with cirrhosis secondary to hepatitis C virus, in whom colonoscopy demonstrated the presence of colonic vascular lesions with cherry spots appearance in the rectum and left colon that vanished two weeks after liver transplantation. The disappearance of mucosal lesions after liver grafting suggest a relation ship among them and portal hypertension.

Colonic Diseases↗
PubMed1995

[The liver transplant program of the Hospital General Universitario Gregorio Marañón: an analysis of the first 100 patients].

During a 3-year period between 1990 and 1993, 100 patients received orthotopic liver transplantation at the "Gregorio Marañón" University General Hospital. The mean age of the patients was relatively high (46.9 +/- 10 years), with an important number of cirrhotic patients (91%). The rate of primary liver failure was relatively low (4.5% of transplantations) although 12 cases with more than 55 years were included in the present series. Eleven retransplantations were performed, 8 for early failure of the graft and 3 for chronic failure. Postoperative complications of the graft were vascular in 9 cases, biliary in 17 cases, and acute rejection (cellular) in 70 patients, although only 50 of these patients required treatment with steroid boluses. Infections were diagnosed in 60 cases with 80% of major infections, 6 of them caused by Aspergillus fumigatus that were lethal in all the cases. Postoperative survival was 82%, 72%, 69% and 69% at 1 month, 6 months, 1 year and 2 years respectively.

Adult↗
PubMed1995

Homocysteinaemia after methionine overload as a coronary artery disease risk factor: importance of age and homocysteine levels.

BACKGROUND: Homocysteinaemia is now accepted as an independent risk factor for coronary artery disease (CAD). Our goal was to study the influence of age plasma homocysteine level on the CAD risk attributable to homocysteinaemia. METHODS: We studied a group of 98 patients under 55 years of age who had suffered a myocardial infarction 3-12 months before the study. The patients were matched by sex and age with a group of 98 controls without vascular disease. We measured the plasma homocysteine levels 6h after a methionine overload of 0.1 g/kg body weight in patients and controls. Afterwards, the odds ratio for homocysteinaemia was determined by homocysteine level, and that for hyperhomocysteinaemia (homocysteine level > 34 mumol/l) by age group. RESULTS: After methionine loading, the homocysteine odds ratio varied from 0.47 (homocysteine level < 23 mumol/l) to 2.88 (homocysteine level > 34 mumol/l). In patients under the age of 46 the odds ratio for hyperhomocysteinaemia was 18.6. In patients between 46 and 55 years of age the odds ratio for hyperhomocysteinaemia was 1.2. CONCLUSIONS: Low homocysteine levels are protective against CAD, and the higher the homocysteine level the higher the coronary risk appears to be. This clearly means that heterozygosity for cystathionine beta synthase deficiency alone is not enough to explain the vascular risk associated with homocysteinaemia. Hyperhomocysteinemia was shown to be a significant risk factor only in patients under the age of 46 years old.

Age Factors↗
PubMed1994

Ocular blood flow velocity reduction after buckling surgery.

BACKGROUND: It has been reported that scleral buckling reduces the blood flow velocity in retinal vessels. Blood flow changes may also appear in other ocular and extraocular vessels. This study describes the blood flow velocity changes in the ophthalmic artery (OA) after performing this procedure. METHODS: The study was carried out in 12 patients (12 eyes) with rhegmatogenous retinal detachment. Color Doppler imaging was used to measure the peak and average blood flow velocity in the OA. Measurements were taken 1 day before and 2 days after scleral buckling surgery was performed. Intraocular pressure (IOP) was measured prior to each ultrasound study. RESULTS: We found that statistically significant reductions in the peak flow velocity (33%) and average flow velocity (31%) occur in the OA after scleral buckling. All patients showed an increase in IOP after surgery. CONCLUSION: Buckling surgery reduces the blood flow velocity in the OA. Since the OA is the origin of the arterial branches that supply blood to the eye, our results suggest that scleral buckling may decrease not only retinal but also choroidal blood perfusion. Some extraocular structures might also be affected.

Adult↗
PubMed1994

Attenuation of adjuvant arthritis in rats by treatment with oxygen radical scavengers.

The contribution of reactive oxygen species (ROS), in particular hydroxyl radical (OH.), to joint inflammation was examined in rats developing adjuvant arthritis (AA) by treatment with ROS scavengers dimethylthiourea (DMTU) and DMSO. Adjuvant arthritis was induced in Sprague-Dawley (SD) rats by a single intradermal (i.d.) injection of Mycobacterium tuberculosis (MT) in oil on day 0. By day 14, all rats exhibited arthritis in the hindlimbs and the majority had involvement of the forelimbs. A marked inflammatory cell influx (75% neutrophils) was present in the synovial fluid. These cells, in vitro, spontaneously produced OH. (0.96 +/- 0.28 OH. units/h per 10(5) cells). In contrast, spontaneous OH. production by normal circulating leucocytes was absent (0.07 +/- 0.03 OH. units/h per 10(5) cells). Adjuvant-injected rats were treated with DMTU (500, 250 and 100 mg/kg), DMSO (330 and 165 mg/kg) or saline (disease control) once daily on days 8, 9 and 10 and twice daily on days 11, 12 and 13 postadjuvant injection. Both DMTU and DMSO significantly reduced the clinical evidence of arthritis (clinical scores: DMTU [500 mg/kg] = 0, P < 0.0001; DMSO [3.0 mL/kg] = 0.4 +/- 0.3, P < 0.01, compared with disease control = 2.3 +/- 0.3). Synovial fluid cell accumulation was also significantly reduced (DMTU [500 mg+kg] = 0.5 +/- 0.1 x 10(5) cells/four joints, P < 0.0001; DMSO [3.0 mL/kg] 2.75 +/- 1.9 x 10(5) cells/four joints, P < 0.01 compared with disease control = 11.76 +/- 1.7 x 10(5) cells/four joints). Neither treatment inhibited cutaneous delayed type hypersensitivity (DTH) to the disease inducing antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

T (Thomsen-Friedenreich) antigen and other simple mucin-type carbohydrate antigens in precursor lesions of gastric carcinoma.

In a previous report we suggested that T antigen appeared to be associated with gastric carcinoma. To verify this hypothesis and characterize the pattern of expression of simple-mucin type carbohydrate antigens (Tn,sialyl-Tn and T before and after neuraminidase) in normal gastric mucosa and precursor lesions of gastric carcinoma, we studied the mucosa adjacent to 100 cases of gastric carcinoma, gastric biopsies of 60 dyspeptic patients, eight adenomatous polyps and eight hyperplastic polyps. The expression of the antigens was more related to the cell type and underlying lesions than to the coexistence of carcinoma. The most distinctive findings concerned intestinal metaplasia, dysplasia and hyperplastic lesions. In intestinal metaplasia, Tn was found mostly in columnar cells and sialyl-Tn in goblet cells. T was more prevalent in incomplete intestinal metaplasia than in complete. A high prevalence of sialyl-Tn expression and cell membrane immunoreactivity for T antigen, similar to those previously found in gastric carcinomas, were observed in three adenomatous polyps, one hyperplastic polyp, five cases of adenomatous dysplasia in the neighbourhood of intestinal carcinomas and four cases of marked foveolar hyperplasia, three of which were from the mucosa adjacent to diffuse carcinomas. We conclude that adenomatous and hyperplastic lesions share with gastric carcinomas features of aberrant glycosylation, namely the cell membrane expression of T antigen.

Adenocarcinoma↗
PubMed1994

Oral tolerance: immunologic mechanisms and treatment of animal and human organ-specific autoimmune diseases by oral administration of autoantigens.

Oral tolerance is a long recognized method to induce peripheral immune tolerance. The primary mechanisms by which orally administered antigen induces tolerance are via the generation of active suppression or clonal anergy. Low doses of orally administered antigen favor active suppression whereas higher doses favor clonal anergy. The regulatory cells that mediate active suppression act via the secretion of suppressive cytokines such as TGF beta and IL-4 after being triggered by the oral tolerogen. Furthermore, antigen that stimulates the gut-associated lymphoid tissue preferentially generates a Th2 type response. Because the regulatory cells generated following oral tolerization are triggered in an antigen-specific fashion but suppress in an antigen nonspecific fashion, they mediate "bystander suppression" when they encounter the fed autoantigen at the target organ. Thus it may not be necessary to identify the target autoantigen to suppress an organ-specific autoimmune disease via oral tolerance; it is necessary only to administer orally a protein capable of inducing regulatory cells that secrete suppressive cytokines. Orally administered autoantigens suppress several experimental autoimmune models in a disease- and antigen-specific fashion; the diseases include experimental autoimmune encephalomyelitis (EAE), uveitis, and myasthenia, collagen- and adjuvant-induced arthritis, and diabetes in the NOD mouse. In addition, orally administered alloantigen suppresses alloreactivity and prolongs graft survival. Initial clinical trials of oral tolerance in multiple sclerosis, rheumatoid arthritis, and uveitis have demonstrated positive clinical effects with no apparent toxicity and decreases in T cell autoreactivity.

Administration, Oral↗