Biomedical subjects
Publications and source records attributed to R Teles.
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BACKGROUND: Cardiac Troponins (cTn) are useful in unstable angina (UA). Moreover the different elevation patterns that can be observed in this condition seem to have different prognostic implications. AIM: To study cTn kinetics and cTn nadir in patients with UA, defined as angina at rest within the last 24 hours before admission accompanied by ischemic ECG changes and no myocardial infarction (MI) enzymatic criteria. POPULATION AND METHODS: Samples were collected from 156 patients for cardiac enzymes and cTnI at admission and at 6, 12, 18 and 24 hours. The chemilluminescence method (Access/Sanofi Pasteur) was used for cTnI. The primary end-point at 30 days was the combined occurrence of death, MI and recurrent ischemia. RESULTS: All determinations were below 0.10 ng/ml (group N) in 114 patients and the other 42 pts (group P) had at least one value equal to or above 0.10 ng/ml. The primary endpoint was observed in 24.6% of group N pts compared with 45.2% of group P pts (p = 0.02). Three different patterns of cTnI kinetics were observed. This enabled the identification of a subgroup--group N pts with increasing cTnI values within the first 12 hours and a total differential value > or = 0.03 ng/ml--with an increased risk (50.0% versus 21.4%--p = 0.02--Kaplan-Meier test). CONCLUSION: Besides the prognostic value conferred by cTnI elevation, cTnI kinetics analysis established another sub-group of patients with an adverse prognosis at 30 days follow-up, despite having a negative cTnI.
The effectiveness of traditional endodontic intracanal medications in reducing bacterial numbers and preventing acute flare-ups and pain continues to be questioned. In the present study, a new local delivery device was developed that releases a substantive dose of clindamycin into root canals. Clindamycin-impregnated ethylene vinyl acetate (EVA) fibers were produced, and the sensitivity of common endodontic microbes to the fibers were established. An in vitro model was developed to persistently infect 32 extracted human teeth with endodontic pathogens to test the efficacy of the clindamycin/EVA fibers in reducing the number of colony-forming units. The clindamycin/EVA fibers were shown to be effective in reducing growth of common endodontic microbes on blood agar plates, and in significantly reducing growth of Prevotella intermedia, Fusobacterium nucleatum, and Streptococcus intermedius in extracted human teeth, thus indicating merit in further exploring the potential of these fibers as intracanal medications.
BACKGROUND: To assess the efficacy of a new catheter for intraoperative radiofrequency ablation. METHODS: We operated 35 mitral patients with atrial fibrillation of which 27 had chronic atrial fibrillation with a mean duration of 8 +/- 6 years. Most patients were in functional class III or IV. All patients were operated under cardiopulmonary bypass using sternotomy in 29 patients, right thoracotomy in 5 and left thoracotomy in 1. RESULTS: Bilateral pulmonary vein isolation with radiofrequency catheter ablation was achieved in 7 +/- 4 minutes. There was no mortality or morbidity. Out of the 27 patients with one to three months follow-up 60% were out of atrial fibrillation and 48% had both atria contracting (scores 3 and 4). A longer time is required to assess the end result of these techniques, because the complete healing of the ablation lesions takes 3 to 6 months. CONCLUSIONS: We conclude that with appropriate tools and settings the use of intraoperative radiofrequency catheter ablation is fast, safe and effective. Its indications can be extended to other types of atrial fibrillation patients.
OBJECTIVE: To analyse the initial experience in peripheral arterial revascularization, using percutaneous techniques, by interventional cardiologists. DESIGN: Retrospective clinical study. SETTING: Cardiology department of a specialised public non-university hospital. PATIENTS: Twenty patients, 18 male and 2 female, with ages between 37 and 84 years, who underwent peripheral interventions between May 5 1989 and February 20 1998. INTERVENTIONS: Patients were subdivided into two groups: Group I, 9 patients, 8 male, average age of 56 +/- 13 years, undergoing renal artery angioplasty; Group II, 11 patients, 10 male, average age of 63 +/- 10 years, undergoing angioplasty of the distal aorta (1), of the right subclavian artery (1), of the iliac arteries (6) and of the femoral arteries (3). In Group I, 11 arteries were dilated, 6 by balloon angioplasty and 5 with stent implantation (Palmaz-Schatz--4 and Symphony--1). In Group II, 12 arteries were dilated, 5 by balloon angioplasty and 7 with 12 stent implantations (Palmaz-Schatz--6, Symphony--5 and NIRTM--1). In 8 patients, 1 of Group I and 7 of Group II, coronary angioplasty was also performed in 14 arteries and 18 segments, exclusively by balloon (3 patients) or with 10 stent implantations (5 patients). RESULTS: There was angiographic success in all patients (100%) and clinical success in 85% (17/20) of patients. All clinical complications occurred in Group I patients: retroperitoneal bleeding in one; right femoral artery pseudoaneurysm requiring surgery in one patient: acute renal failure in one patient. There were no cardiac complications in patients undergoing peripheral and cardiac angioplasties at the same stage. In the mean follow-up period of 26 months, one patient required reangioplasty of a right iliac artery and another underwent iliac-femoral bypass, both of Group II and before peripheral stents were available. CONCLUSIONS: Percutaneous peripheral arterial revascularization performed by experienced interventional cardiologists seems safe and efficient, being perfectly justified in patients requiring simultaneous coronary angioplasty.
Periapical inflammatory responses occur as a consequence of bacterial infection of the dental pulp, as a result of caries, trauma, or iatrogenic insult. Periapical inflammation stimulates the formation of granulomas and cysts, with the destruction of bone. These inflammatory responses are complex and consist of diverse elements. Immediate-type responses--including vasodilatation, increased vascular permeability, and leukocyte extravasation--are mediated by endogenous mediators, including prostanoids, kinins, and neuropeptides. Non-specific immune responses--including polymorphonuclear leukocyte and monocyte migration and activation, and cytokine production--are elicited in response to bacteria and their products. Interleukin-1 and prostaglandins in particular have been implicated as central mediators of periapical bone resorption. Chronic periapical inflammation further involves specific T- and B-cell-mediated anti-bacterial responses, and activates a network of regulatory cytokines which are produced by Th1- and Th2-type T-lymphocytes. Various naturally occurring and genetically engineered models of immunodeficiency are beginning to help elucidate those components of the immune system which protect the pulpal/periapical complex. Both specific and non-specific responses interface with and are regulated by the neural system. The modulation of these responses by immune response modifies, cytokine antagonists, and other novel therapeutic agents is discussed. As an experimental model, periapical inflammation has many advantages which permit it to be used in studies of microbial ecology and pathogenesis, host response, neuroimmunology, and bone resorption and regeneration.
Specific immunity has been implicated in the pathogenesis of periapical lesions, although the extent to which these mechanisms are actually involved in either protection or destruction of the pulp-periapex complex is yet to be established. To investigate this question we compared periapical-lesion pathogenesis in RAG-2 severe combined immunodeficient (SCID) mice with immunocompetent control mice following surgical pulp exposure. In order to equalize the bacterial challenge, an infection protocol using Prevotella intermedia, Fusobacterium nucleatum, Peptostreptococcus micros, and Streptococcus intermedius was devised. The results demonstrated that after infection, the proportion of the root canal flora represented by the four pathogens was almost identical in both groups (39.9 and 42.2% for RAG-2 and immunocompetent control mice, respectively). The effects of abrogation of T- and B-cell mechanisms on periapical pathogenesis were then assessed. Approximately one-third of the RAG-2 mice developed endodontic abscesses, while no immunocompetent controls had abscesses, results which indicated regional dissemination of the infection. A similar incidence of abscesses was found in two additional experiments. Abscessed RAG-2 teeth had significantly larger periapical lesions than did nonabscessed RAG-2 teeth (P < or = 0.05) and exposed immunocompetent controls (P < or = 0.01), whereas nonabscessed RAG-2 teeth were not significantly different from those of exposed immunocompetent controls in periapical-lesion size. We conclude that B- and T-cell-mediated immunity protects the host from the dissemination of endodontic infections and that RAG-2 mice are more susceptible to infection-induced pulp-periapex destruction.