Biomedical subjects

L A Silva

Publications and source records attributed to L A Silva.

At least 37 records · Page 2Linked to original sources

PubMed1996

Anaerobic microorganisms in root canals of human teeth with chronic apical periodontitis detected by indirect immunofluorescence.

Aiming to assess the presence of selected anaerobic microorganisms in root canals of human teeth with chronic apical periodontitis. 25 central and lateral upper incisors presenting with radiographic evidence of chronic apical periodontitis were studied. The pulp chamber was opened under aseptic conditions and samples of the root canal content were collected with sterile absorbent paper points, which were placed and dispersed in test tubes containing reduced transport medium RTT. Aliquots were dried on glass slides and stained by indirect immunofluorescence for detection of Actinomyces viscosus, Fusobacterium nucleatum, Porphyromonas gingivalis and Prevotella intermedia. The results showed a positive indirect immunofluorescence reaction in 24 of the 25 samples. Fourteen were positive for the specie Actinomyces viscosus, 12 for Prevotella intermedia, 10 for Fusobacterium nucleatum and 4 for Porphyromonas gingivalis. A semiquantitative assay was easily implemented for assessment of degree of infection by the organisms in individual cases.

Actinomyces viscosus↗

PubMed1996

Effect of fasting on insulin signaling in the aorta of intact rats.

Insulin stimulates the tyrosine kinase activity of its receptor, resulting in the phosphorylation of its cytosolic substrate, insulin receptor substrate 1 (IRS-1). Previous studies have demonstrated a tissue-specific regulation of IRS-1. In the present study we investigated the levels and phosphorylation state of IRS-1 after insulin stimulation in the rat aorta in vivo, and the modulation of this protein after 72 h of fasting, using immunoprecipitation and immunoblotting with anti-insulin receptor, anti-IRS-1 and antiphosphotyrosine antibodies. We show that IRS-1 is present in rat aorta, and is tyrosine phosphorylated after insulin stimulation. After insulin stimulation, rats fasted for 72 h showed an increase in insulin receptor (100 +/- 45%, P < 0.05) and IRS-1 phosphorylation (68 +/- 24%, P < 0.05) in aorta, compared to fed rats. There was no change in insulin receptor of IRS-1 protein levels in fasted rats. In summary, the present study demonstrated that proteins involved in the early steps of insulin signal transduction are present in the rat aorta and can be modulated by fasting. It will be of interest to study the regulation of these proteins in the aorta of animal models of hypertension and/or atherosclerosis.

Animals↗

PubMed1993

Randomized trial of direct coronary angioplasty versus intravenous streptokinase in acute myocardial infarction.

OBJECTIVES: The objective of this study was to obtain preliminary data on the relative clinical utility of direct coronary angioplasty compared with that of intravenous thrombolytic therapy for patients with acute myocardial infarction. BACKGROUND: The relative merits of intravenous thrombolytic therapy and direct coronary angioplasty as treatment for acute myocardial infarction are incompletely understood, and randomized trials of these treatments have been extremely limited. METHODS: One hundred patients with ST segment elevation presenting to a single high volume interventional center within 6 h of the onset of chest pain were randomized to receive either streptokinase (1.2 million U intravenously over 1 h) or immediate catheterization and direct coronary angioplasty. Patients were excluded for age > or = 75 years, prior bypass surgery, Q wave infarction in the region of ischemia or excessive risk of bleeding. All patients were then treated with aspirin (325 mg orally/day) and heparin (1,000 U intravenously/h) for 48 h until catheterization was performed to determine the primary study end point, namely, infarct-related artery patency at 48 h. Secondary end points were in-hospital death, left ventricular ejection fraction at 48 h and time to treatment. RESULTS: There was no difference in the baseline characteristics of the two treatment groups. Overall patient age was 56 +/- 10 years, 83% of patients were male, 11% had prior infarction, 40% had anterior infarction and 97% were in Killip class I or II. Although time to treatment was delayed in the angioplasty group (238 +/- 112 vs. 179 +/- 98 min, p = 0.005), there was no difference in 48-h infarct-related artery patency or left ventricular ejection fraction (patency 74% vs. 80%; ejection fraction 59 +/- 13% vs. 57 +/- 13%; angioplasty vs. streptokinase, p = NS for both). There were no major bleeding events, and the mortality rate with angioplasty (6%) and streptokinase (2%) did not differ (p = NS). CONCLUSIONS: These results suggest that intravenous thrombolytic therapy might be preferred over coronary angioplasty for most patients because of the often shorter time to treatment.

Aged↗

PubMed1993

Aetiology of acute diarrhoea in hospitalized children in Rio de Janeiro City, Brazil.

Enteropathogens were investigated in 406 children aged 0-3 years with diarrhoea attending the Salles Neto Municipal Hospital. Enteric bacterial pathogens were isolated from 49 per cent of the children. Enterotoxigenic Escherichia coli (ETEC) (20.9 per cent), enteropathogenic E. coli (EPEC) (16.5 per cent), rotavirus (11.6 per cent), and Campylobacter (9.9 per cent) were the most common agents. Among clinical features, vomiting and fever were significantly associated with Rotavirus isolation (50.0 per cent), respiratory infection with Adenovirus (14.3 per cent), bloody diarrhoea with Campylobacter (12.5 per cent), and dehydration with EPEC (71.6 per cent).

Adenoviridae↗

PubMed1993

Viral, bacterial and parasitic pathogens associated with severe diarrhoea in the city of São Paulo, Brazil.

Viral, bacterial and parasitic pathogens associated with diarrhoea were studied in infants and young children admitted to the paediatric clinic of the University Hospital of São Paulo during the period of 13 months. A recognised pathogenic organism was detected in 78% of the diarrhoeic patients, 6% of whom had a mixed infection with two agents. Enteropathogenic E. coli (EPEC) was the most common enteropathogen detected (22%), followed by rotavirus (19%) and adenovirus (10%). Altogether 6% had diarrhoea associated with Salmonella or Shigella and 3% showed diarrhoeal illness associated with astrovirus. Infants less than 6 months of age were most commonly infected with enterobacteria (35%), mainly enteropathogenic E. coli (30%), whereas children 6 months to 2 years presented more often with viruses (38%), mainly rotaviruses (25%). Enteropathogens were found during all seasons of the year and rotaviruses showed a seasonal variation.

Acute Disease↗

PubMed1993

[Detection of myocardial ischemia during dobutamine stress echocardiography. Correlation with coronary cineangiography].

PURPOSE: To detect myocardial ischemia during dobutamine stress echocardiography (DSE). METHODS: Two hundred and seventy one patients were studied; 63 (23%) underwent coronary angiography within a month of DSE. Angiograms were analyzed independently by 3 angiographers, and coronary lesions larger than 50% of luminal occlusion were considered likely to cause ischemia. RESULTS: The global sensitivity and specificity were 95% and 75% respectively, with 89% accuracy. Of 43 patients showing obstructive coronary artery disease, there were 2 false negatives. One of 5 false positives had ischemic cardiomyopathy and another a technically difficult exam. The symptoms and side effects in decreasing order of occurrence are as follows: palpitation 46%; arrhythmia 24%; mild hypotension 24%; chest pain 8%; hypertension 5%; facial paresthesia 4%; chills 1.8%; nausea 1.8%; headache 1.4%; dyspnea 0.4% and severe hypotension 0.4%. CONCLUSION: Considering the results, the small number of complications and the feasibility, DSE seems to be a safe and promising method for detecting myocardial ischemia.

Adult↗

PubMed1992

[Evaluation of household chemical disinfectants for Vibrio cholerae EL TOR (non toxigenic strain)].

The methodology of microbiological evaluation of disinfectants in permanently being questioned because the laboratorial protocols do not correspond to the real conditions under which these products are used. In 1985 the Use-Dilution method of AOAC was adopted in Brazil for microbiological qualification of chemical disinfectants for commercial purposes. Domestic disinfectants are tested in this way against Salmonella choleraesuis and Staphylococcus aureus ATCC strains, was chosen for this evaluation Vibrio cholerae in view of its current importance in Brazil, in terms of Public Health associated with the study of the disinfectant's antimicrobial activities. Nineteen disinfectant products for domestic use for available to the public were evaluated microbiologically by means of simplified Use-Dilution test with 10 carriers. The active compounds of the products included formaldehyde, phenols, cresols, quaternary ammonium compounds, chlorine and ethanol. Seven were mixtures of these. According to the recommendations for their use, sixteen products should be used undiluted. Under these conditions, 9 disinfectants were vibriocides and 7 did not demonstrate this antibacterial activity. Four products in dilutions not clearly specified were also ineffective. The vibriocide products which must used without dilution were tested again, diluted at 1:2. These solutions did not inactivate V. cholerae showing that, microbiologically, their active compounds are used in limited concentrations. Commercial alcohol (95.5 degrees GL) at 1:3, chlorine 2.8% Agua sanitária at 1:200 and Lysoform at 1:20 came up to the standards required by the test.

Disinfectants↗

PubMed1991

[Thrombolysis with intravenous APSAC in patients with acute myocardial infarction].

PURPOSE: Analysis of the first 20 patients with acute myocardial infarction (AMI) who were treated with intravenous APSAC. METHODS: Twenty patients with AMI less than 6 hours of duration of symptoms were treated with IV APSAC bolus of 30 mg. Seventeen were males, ages ranging between 40 and 73 (mean 54) years. The first angiographic study was performed in 90 minutes and 5-7 days after drug administration. RESULTS: In the angiographic study performed at 90 minutes the infarct--related artery were left anterior descending (LAD) in 7 patients (35%), right coronary artery (RCA) in 9 (45%) and left circumflex (LCX) in 4 (20%). In 14 (70%) of the patients had patent infarct-related artery and the mean of left ventricular ejection fraction (LVEF) was 0.49 +/- 0.15. In six non recanalized patients the mean LVEF was 0.40 +/- 0.14. No complications were observed, and in the second angiographic study one patient showed reocclusion of the infarct-related artery. CONCLUSION: Because of easy application (IV bolus), no complication and high rate of early recanalization, IV APSAC seems to be an efficient thrombolytic agent in the treatment of patients with AMI.

Adult↗

PubMed1991

[Myocardial revascularization after reperfusion in the acute phase of myocardial infarction].

PURPOSE: To evaluate the coronary artery bypass grafting (CABG) after successful coronary reperfusion (CR) by streptokinase and/or percutaneous transluminal coronary angioplasty in acute myocardial infarction (AMI). PATIENTS AND METHODS: During 65-months period, 245 patients underwent CR during AMI. In 47 (19.2%) CABG were performed in the acute period due to multi-vessel disease (31%), residual lesion (20%) and post-reperfusion angina (17%). There were two distinct periods: in the first, between Jun/81 and Jun/83, 34 patients underwent CABG, 47 hours average after reperfusion; in the second, between Jul/83 and Nov/86, 13 patients underwent CABG, 7 days average after reperfusion. RESULTS: There were 7 deaths (21%) in the first period and 1 (8%) in the second one. CONCLUSION: After a multifactorial analysis the authors concluded that better results with inferior mortality (p less than 0.05) were obtained when CABG was performed later (mean 7 days) than in the immediate post-reperfusion period (mean 47 hours).

Adult↗

PubMed1990

[Thrombolysis in acute myocardial infarction. Streptokinase or r-TPA?].

PURPOSE: To compare the results of intravenous thrombolytic therapy with streptokinase (SK), with those of the recombinant human tissue-type plasminogen activator (r-TPA), in acute myocardial infarction (AMI). MATERIAL AND METHODS: One hundred patients with AMI of less than 6 hours duration were randomized in two groups: 50 patients were allocated to 1.200.000 IU of SK (Group SK) and 50 patients received 100 mg of r-TPA over 180 minutes. The two groups were similar respecting age, sex, location and previous infarction. The angiographic study was performed 48 h after the thrombolytic therapy. RESULTS: In the angiographic study, 85% of the Group SK vs 66% of Group r-TPA had patient infarct-related vessel (p = 0.025). Reocclusion was 6.6% in Group SK vs 19% in Group r-TPA and hospital mortality was similar in the two groups. CONCLUSION: In the late angiographic evaluation (48 h), the frequency of coronary patency was found to be higher after intravenous SK than after intravenous r-TPA.

Blood Pressure↗

PubMed1989

[Treatment of pulmonary thromboembolism with extrinsic plasminogen activator. A case report].

A 49 year-old woman with acute pulmonary thromboembolism and severe hemodynamic impairment was successfully treated with tissue-type plasminogen activator (r-TPA). She did not have previous pulmonary or cardiac diseases. Thirty days after immobilization of the right ankle, she had a sudden onset of dyspnea, epigastrial pain and syncope. As heparin therapy was unsuccessful, 90 mg of IV r-TPA was administered. There was rapid clinical and hemodynamic improvement of her condition. Pulmonary scanning one week later was normal and she was discharged without symptoms 12 days after the acute episode.

Electrocardiography↗

PubMed1989

[Coronary angioplasty in elderly patients. A therapeutic option].

Of 304 consecutive percutaneous transluminal coronary angioplasties (PTCA) performed between March 86 and March 88, 61 patients were 65 years or older. The indications for PTCA were: stable angina, unstable angina and acute myocardial infarction with suitable anatomy. In elderly patients, the female sex, and the calcific deposits, were more frequent than in the younger group (p less than 0.0001). Primary success was achieved in 82%, vs 88% in patients younger than 65 years; complications and mortality were also statistically irrelevant between the two groups. Late clinical follow-up ranging from 3 to 36 months (mean 10) showed that symptomatic improvement was achieved in 86% of elderly patients in whom PTCA was successful (vs 80% in the younger group). These data support the safety and clinical effectiveness of PTCA in elderly symptomatic patients with suitable anatomy.

Age Factors↗

PubMed1988