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A R Dias

Publications and source records attributed to A R Dias.

At least 19 recordsLinked to original sources
PubMed2006

Does caffeine modify corticomotor excitability?

AIMS: To test the influence of caffeine on the lower and upper motor neuron excitability. METHODS: In Experiment A, 18 healthy subjects received 200 mg of caffeine or placebo, in a randomized, double-blind, placebo-controlled design protocol. Mean F-waves amplitude, amplitude of the motor response evoked by magnetic stimulation (MEP), MEP duration, cortical silent period (CSP), central conduction time, and cortical threshold were evaluated. In Experiment B, 6 healthy controls received 400 mg of caffeine, the peripheral silent period (PSP) and CSP were evaluated. CSP was recorded bilaterally in biceps brachii (intensity 10% above threshold) and abductor digiti minimi (ADM) (intensity at 10% and 50% above threshold). Muscle contraction was above 50% of the maximum force in both experiments. Latencies were defined by a technician who was not aware of this investigation. Serum caffeine level was evaluated. RESULTS: In Experiment A, only the CSP, recorded in both ADM with intensity at 10% above threshold showed a significant change after caffeine (decrease of 17.1+/-34.0 ms, about 12% reduction). In Experiment B, PSP did not change, but CSP tested with intensities 10% above threshold was significantly decreased by 20.8+/-34.4 ms in ADM and 13.5+/-13.8 ms in biceps (about 13 and 16%, respectively). Serum caffeine level clearly increased after consumption but no correlation could be found between these levels and CSP reduction. CONCLUSIONS: In our investigation, caffeine elicited a consistent decrease of the CSP, suggesting that caffeine increases cortical neuronal excitability.

Adult↗
PubMed2005

Chlorobis(dimethylamido)(eta5-2,5-dimethylpyrrolyl)titanium(IV), [Ti(NMe2)2(DMP)Cl].

The structure of the title compound, [Ti(C2H6N)2(C6H8N)Cl], displays a eta5-coordination mode for the pyrrolyl ring, confirmed by the values of the slip parameter [0.073 (9) A] and the fold angle [4.6 (6) degrees ]. This coordination is confirmed by NMR data, which point to the involvement of the complex in a fluxional process in solution above 285 K, passing through an intermediate involving simultaneously a metal-azaallyl and a metal-olefin bond.

Journal Article↗
PubMed2005

Effects of conjugated equine estrogens or raloxifene on lipid profile, coagulation and fibrinolysis factors in postmenopausal women.

OBJECTIVES: To compare the effect of conjugated equine estrogens (CEE) and raloxifene on lipid profile and hemostasis. MATERIALS AND METHODS: A double-blind, randomized and parallel study was performed with 90 healthy postmenopausal women, aged 54 +/- 5 years, divided into three groups and submitted to daily therapy with either CEE 0.625 mg, raloxifene 60 mg or placebo for 4 months. The lipid profile, coagulation and fibrinolytic factors were analyzed. RESULTS: CEE increased the levels of high density lipoprotein cholesterol (HDL-C) from 49.0 to 56.8 mg/dl (p < 0.001), very low density lipoprotein cholesterol (VLDL-C) from 17.2 to 22.3 mg/dl (p < 0.001), and triglycerides from 86.0 to 111.7 mg/dl (p < 0.001), and decreased the levels of low density lipoprotein cholesterol (LDL-C) from 121.0 to 106.5 mg/dl (p < 0.001). The only significant effect of raloxifene was an increase in the levels of HDL-C from 46.0 to 47.8 mg/dl (p = 0.019). There was no significant reduction in LDL-C, from 115.5 to 110.2 mg/dl (p = 0.06), VLDL-C, from 21.7 to 20.0 mg/dl (p = 0.201), and triglycerides, from 108 to 100 mg/dl (p = 0.201). CEE decreased the levels of fibrinogen, from 370.5 to 326.8 g/l (p = 0.039) and the levels of antithrombin III, from 99.5 to 93.2% (p < 0.001). Raloxifene decreased the levels of fibrinogen, from 354.7 to 302.0 g/l (p = 0.009) and the levels of antithrombin III, from 102.4 to 98.5% (p = 0.039). CEE increased levels of protein C from 103.7 to 115.3 mg/l (p < 0.001) and raloxifene did not change the levels of protein C (107.9 to 105.1 mg/l; p = 0.158). CEE decreased the antigen levels of tissue plasminogen activator (t-PA) from 8.8 to 6.8 U/ml (p < 0.001), and of plasminogen activator inhibitor (PAI-1) from 30.8 to 21.6 U/ml (p < 0.010), whereas raloxifene had no significant effect on either t-PA, from 9.6 to 9.2 U/ml (p = 0.235) or PAI-1 antigen levels, from 32.1 to 30.4 U/ml (p = 0.538). CONCLUSION Both CEE and raloxifene exert significant effects on the lipid and coagulation profile. CEE had a more significant effect on fibrinolysis than raloxifene. These effects may have a significant impact on the cardiovascular risk that needs to be confirmed in larger studies.

Adult↗
PubMed2004

Inclusion of lidocaine in cardioplegic solutions provides additional myocardial protection.

AIM: Lidocaine inhibits depolarization by blocking sodium and calcium influx and potassium release, abolishing the action potentials of cells in the Hiss-Purkinje system and myocit cells. As it can directly influence cardiac electric and mechanical activities, this study evaluated the efficacy of lidocaine in providing myocardial protection during normothermic blood cardioplegia. METHODS: Twenty-six dogs were randomly assigned to groups based on the cardioplegic induction solution they were to receive. Group I dogs (n=10) received a solution consisting of lidocaine (5 mg/kg), KCL (41.6 mEq/L) and 180 ml of normothermic blood. Group II dogs (n=10) received the same solution, except for the lidocaine and group III dogs (n=6) received only normothermic blood. In addition, 120 ml of normothermic blood was reinfused every 20 min. All dogs underwent cardiopulmonary bypass, 2 hours of global myocardial ischemia and 3 hours of reperfusion. Statistical differences were determined with the chi squared test, the two-way analysis of variance and Bonferroni's test. RESULTS: There were no deaths in group I. The survival rate in group II was 60%, and no dogs in group III survived (p=0.025). No difference in lactate liberation or left ventricular function (i.e., cardiac outflow and ejection fraction) was observed between groups. However, animals in group I demonstrated less enzymatic releases (troponin I, p=0.049 and CK, p=0.026) and less mitochondrial ultrastructural changes (p=0.022). CONCLUSIONS: Lidocaine offers myocardium additional protection against ischemia during cardiopulmonary bypass.

Animals↗
PubMed2001

Downmodulation of CD18 and CD86 on macrophages and VLA-4 on lymphocytes in experimental tuberculosis.

Development and evaluation of new vaccines and immunotherapy against tuberculosis demand a better understanding of the immune mechanisms in this disease. Costimulatory signals and intercellular contact seem to be pivotal in determining whether recognition of antigen by T cells leads to activation or anergy. In this paper, we show that virulent M. tuberculosis H37Rv downmodulates the ex vivo expression of CD18 and CD86 on peritoneal macrophages and VLA-4 on lymphocytes but does not disturb the in vitro production of interleukin (IL)-12 and interferon (IFN)-gamma after intraperitoneal infection. In addition, splenocytes from infected mice produce IL-10, while the expression of cell surface receptors is unchanged. The interplay among IL-12, IFN-gamma and IL-10 in vivo and the downmodulation of cell-surface receptors during the infection at the inflammatory site may contribute to the explanation of the maintenance of infection.

Animals↗
PubMed2001

Mini-sternotomy for the treatment of aortic valve lesions.

OBJECTIVE: To compare inverted-L mini-sternotomy performed above the sternal furcula with conventional sternotomy in patients with aortic valve diseases who undergo surgical treatment. METHODS: We operated upon 30 patients who had aortic valve lesions that had clinical and hemodynamic findings. All patients underwent inverted-L sternotomy, which extended from above the manubrium of the sternum to the 3rd right intercostal space, without opening the pleural cavity. Their ages ranged from 32 to 76 years, and 18 were males and 12 were females. We used negative pressure in a venous 1/4-inch cannula, and the patients were maintained in Trendelemburg's position. Twenty-seven patients received bioprostheses with diameters ranging from 23 to 29mm. Three patients underwent only removal of the calcifications of the aortic valve leaflets and aortic commissurotomy. RESULTS: The mean duration of anoxic cardiac arrest was 63.11min. Access was considered good in all patients. One death was due to pulmonary and renal problems not related to the incision. All patients had a better recovery in the intensive care unit, got out of bed sooner, coughed more easily, and performed prophylactic physiotherapeutic maneuvers for respiratory problems more easily and with less pain in the incision. Early ambulation was more easily carried out by all patients. CONCLUSION: Mini-sternotomy proved to be better than the conventional sternotomy because it provided more comfort for the patients in the early postoperative period, with less pain and greater desire for early ambulation and all its inherent advantages.

Adult↗
PubMed1999

Immediate and long term evolution of valve replacement in children less than 12 years old.

OBJECTIVE: The aim of this work was the follow-up and evaluation of valve replacement in children under 12 years of age. METHODS: Forty-four children less than 12 years old were underwent valve replacement at INCOR-HCFMUSP between January 1986 and December 1992. Forty (91%) were rheumatic, 39 (88.7%) were in functional classes II or IV, 19 (43.2%) were operated upon on an emergency basis, and 6 (13.6%) had atrial fibrillation. Biological prostheses (BP) were employed in 26 patients (59.1%), and mechanical prostheses (MP) in 18 (40.9%). Mitral valves were replaced in 30 (68.7%), aortic valves in 8 (18.2%), a tricuspid valve in 1 (2.3%), and double (aortic and mitral) valves in 5 (11.4) of the patients. RESULTS: Hospital mortality was of 4.5% (2 cases). The mean follow-up period was 5.8 years. Re-operations occurred in 63.3% of the patients with BP and in 12.5% of those with MP (p=0.002). Infectious endocarditis was present in 26.3% of the BP, but in none of the cases of MP (p=0.049). Thrombosis occurred in 2 (12.5%) and hemorrhage in one (6.5%) of the patients with a MP. Delayed mortality occurred in 5 (11.9%) of the patients over a mean period of 2.6 years; four had had BP and one had a MP (NS). Actuarial survival and re-operation-free curves after 10 years were respectively, 82.5+/-7.7 (SD)% and 20.6+/-15.9%. CONCLUSION: Patients with MP required fewer re-operation, had less infectious endocarditis and lower late mortality rates compared with patients with bioprostheses. The former, therefore, appear to be the best valve replacement for pediatric patients.

Atrial Fibrillation↗
PubMed1994

[Ischemic mitral valve insufficiency. Incidence, diagnosis and surgical treatment].

PURPOSE: To study the incidence of ischemic mitral regurgitation (MR) and the mortality. METHODS: One-hundred-five cases of acute myocardial infarction (AMI) with MR were reviewed. Patients were divided in two groups: group A-59 (56.2%) necropsied patients without previous surgical procedures to correlate clinical pictures with the aim to determine the cause of death; group B-46 (43.8%) patients were submitted to surgical treatment. This group was subdivided in mild, moderate and severe forms of MR, and studied comparatively the type of surgical treatment and its evolution. RESULTS: Group A-23 (39%) patients with mild forms and predominant ischemic heart disease, responsible for death; 18 (30.5%) patients without previous diagnosis, masked by myocardial failure and 18 (30.5%) with severe MR and coronary heart disease; group B-14 (30.4%) patients died at the immediate post-operatory period. Higher mortality associated to ejection fraction (EF) below 35% (47.6%; p = 0.022), severe MR (41.7%; p = 0.044) and cardiogenic shock (52.9%; p = 0.14). In 41 (89.1%), the mitral valve repair was combined to coronary artery bypass grafting operation (CABG), in 4 (8.7%) this last procedure was made without mitral repair and in the remaining patients the surgery was limited to the valve. Mitral valvuloplasty was performed in 23 (50%) patients with 3 (13%) deaths, and in 19 (42.3%) the mitral valve was replaced with 9 (47.4%) deaths. CONCLUSION: The prognosis is related to the grade of EF and to the severity of MR. In mild to moderate forms, the surgical indication is due to the associated coronary heart disease and the valvuloplasty is preferred, in this instance. In severe forms, surgical intervention must be performed as soon as possible, before cardiogenic shock appears.

Adult↗