Biomedical subjects

J J de Lima

Publications and source records attributed to J J de Lima.

At least 19 recordsLinked to original sources

PubMed1999

Blood pressure and the risk of complex arrhythmia in renal insufficiency, hemodialysis, and renal transplant patients.

Complex arrhythmia is frequent in hemodialysis patients but it is not clear if this is a consequence of dialysis or uremia or is secondary to the hemodynamic and cardiovascular alterations often associated with chronic renal failure. The incidence of complex ventricular arrhythmia (frequent multiform premature beats, couplets, and runs) in 31 subjects who had their uremic status recently corrected by renal transplant (Group 1) and in 23 predialysis (Group 2) and 73 hemodialysis (Group 3) chronic renal failure patients were studied with 24-h Holter monitoring. Patients were not receiving antiarrhythmic drugs or digitalis and significant coronary artery disease was excluded by clinical and noninvasive methods. Complex arrhythmia was two times more frequent in dialysis patients but the difference did not reach statistical significance (Group 1: 16%; Group 2: 17%; Group 3: 34%; chi2 4.9, P = .086). The stepwise model of logistic regression analysis identified systolic blood pressure (odds ratio 1.015, 95% confidence interval [CI] 1.001-1.027, P = .03) and left ventricular systolic dysfunction (odds ratio 7.04, 95% CI 1.3-36.7, P = .02) as the only factors that independently influenced the probability of complex arrhythmia. Age, gender, race, diabetes, smoking status, body mass index, diastolic blood pressure, serum creatinine, hematocrit, left ventricular mass index, and use of diuretics, beta-blockers, angiotensin converting enzyme (ACE) inhibitors, sympatolytics, and calcium channel blockers did not influence the occurrence of complex arrhythmia. The data indicate that blood pressure and myocardial dysfunction are more important determinants of complex arrhythmia than dialysis or uremia in chronic renal disease patients.

Adult↗

PubMed1998

Cardiac lymphatic dynamics after ischemia and reperfusion--experimental model.

ABSTRACT. The aim of the present study was to investigate the lymphatic cardiac circulation in an experimental model of ischemia plus reperfusion in mongrel dogs (Canis familiaris L). As radiotracer we used 0.2-0.25 ml (111 MBq) of 99mTc-Re2S7 colloid (+/-10 microm), injected subcapsullary below the second diagonal of the descending anterior ligated coronary artery with a special needle. A gamma-camera/Starport + DecStation were used for data acquisition. Four experimental groups with five animals each were established: G I = controls; G II = immediately after acute myocardial infarction (AMI); G III = late infarction (5 days after AMI); G IV = ischemia (90 min) + reperfusion. Four regions of interest (ROIs) were chosen: injection area (ZA), above (ZB), near right (ZD), and far right (ZC) from ZA. Mean disappearance times in ZA and dynamic parameters in the other ROIs were determined from activity/time curves drawn in each area, using homemade software. The results obtained seem to indicate that the methodology is appropriate to a detailed study of lymphatic drainage in pathological situations in animal models.

Animals↗

PubMed1996

Arterial blood pressure and left ventricular hypertrophy in haemodialysis patients.

OBJECTIVE: To test the hypothesis that there is an association between arterial blood pressure and left ventricular hypertrophy and patterns of ventricular geometry, defined echocardiographically, in a group of stable haemodialysis patients with a low prevalence of extrarenal diseases. DESIGN AND METHODS: Patients with end-stage renal failure treated by regular haemodialysis (aged 44.3 +/- 12.9 years, n = 103, among whom 52 men and 23 blacks, dialysis duration 49.8 +/- 35.3 months) were subjected to echocardiographic evaluation (M-mode, bidimensional and Doppler) on the day preceding dialysis. The average of all predialysis blood pressure determinations during the 3 months preceding the tests (34-38 determinations in each patient) were used as baseline data. Univariate and multivariate tests were used to assess the main variables associated with echocardiographically defined cardiac alterations and with patterns of ventricular geometry. RESULTS: The systolic blood pressure was significantly associated with the left ventricular mass index and was significantly and independently correlated with left ventricular hypertrophy, posterior wall hypertrophy, left ventricle dilation and increased relative wall thickness. Other significant correlations were between the haematocrit level and left ventricular hypertrophy and between age and altered systolic and diastolic functions. Concentric ventricular hypertrophy was observed only in patients with a history of hypertension, whereas the prevalence of normal geometry was higher in patients without a history of hypertension. CONCLUSION: The systolic blood pressure is an important factor influencing the occurrence of left ventricular hypertrophy in haemodialysis patients and also affects the left ventricle geometry in this population.

Adult↗

PubMed1995

Plasma lipid profile and coronary artery disease in Brazilian hemodialysis patients.

We studied the prevalence of lipid disorders and of coronary artery disease and the main factors affecting plasma lipids in a cohort of Brazilian hemodialysis patients. The investigation comprised 75 adult hemodialysis patients and 200 normal controls matched for age, sex, race and body mass index. Mean values for plasma lipids were within normal limits in the dialysis group. Total cholesterol (184 +/- 44 vs. 201 +/- 46 mg/dl), LDL (110 +/- 36 vs. 131 +/- 44 mg/dl) and HDL (40 +/- 13 vs. 47 +/- 12 mg/dl) were significantly lower in the dialysis patients (P < 0.01), whereas VLDL (32 +/- 14 vs. 21 +/- 12 mg/dl) and triglyceride (161 +/- 71 vs. 111 +/- 70 mg/dl) were increased (P < 0.01). Increased triglyceride was observed in 24% of the dialysis patients, a prevalence two to three times lower than that reported in the literature. In the dialysis group, the variables positively related to total cholesterol were hypertension (P < 0.05) and gender (female) (P < 0.05); to LDL and HDL, hypertension (P < 0.05 and P < 0.01, respectively); and to triglyceride, use of propranolol (P < 0.01). Age, race, duration of hemodialysis, body mass index and plasma creatinine did not affect plasma lipids. The prevalence of coronary artery disease, established by invasive and noninvasive methods, was 10.7% while in the literature 20-35% of the unselected hemodialysis patients present obstructive coronariopathy. We conclude that the plasma lipid profile of Brazilian hemodialysis patients is similar to those reported in American and European literature, whereas the prevalence of hypertriglyceridemia and of coronary artery disease appears to be reduced.

Adult↗

PubMed1993

Evaluation of pulmonary systemic blood flow using ECG gated acquisition.

We propose a functional parametric analysis method using ECG-gated 99mTc-labeled red blood cell (RBC) imaging for detection and characterization of periodic variations in local blood activity in the lungs during cardiac cycle. We validated in animal experiments that such count variations correlate with cyclical pulmonary blood flow and may be used for evaluation of systemic-to-pulmonary shunts. Clinical studies were performed in 48 patients. After labeling the RBC pool with 99mTc, ECG-gated gamma camera images of both lung fields were acquired and processed to obtain Fourier transforms of time/activity functions in selected regions. The first harmonic parametric images of amplitude and phase were derived. There was an excellent correlation (r = 0.92) between activity variations and pulsatile flow measured by our method with that obtained by the thermodilution method in dog experiments (n = 10) after implantation of a systemic-to-pulmonary shunt. Patient studies showed the technique to be sensitive in detecting and quantifying abnormal systemic-to-pulmonary blood flow. Lung pulsatile flow can thus be noninvasively measured from functional parametric phase and amplitude images; the technique may be useful for detecting and quantifying abnormal systemic-to-pulmonary blood flow in man.

Animals↗

PubMed1991

Ventilation and perfusion display in a single image.

A new method of ventilation and perfusion display onto a single image is presented. From the data on regions of interest of the lungs, three-dimensional histograms are created, containing as parameters X and Y for the position of the pixels, Z for the perfusion and colour for local ventilation. The perfusion value is supplied by sets of curves having Z proportional to the local perfusion count rate. Ventilation modulates colour. Four perspective views of the histogram are simultaneously displayed to allow visualization of the entire organ. Information about the normal ranges for both ventilation and perfusion is also provided in the histograms.

Adult↗

PubMed1988

Equations of simple kinetic models with Gaussian distributions in reaction constants.

The equations of some simple compartmental models obtained when the characteristic functional parameters are supposed to have a Gaussian distribution have been derived in the present paper. It is verified that for some of the studied models the curves that correspond to the equations of the system considering the functional parameters with a Gaussian distribution are different from those with constant parameters equal to the mean of the distribution. The alterations which can result from these distributions in some practical situations are discussed.

Body Fluid Compartments↗

PubMed1988

Cyclosporin A and pressor responsiveness in sheep.

Pressor response to graded infusion of angiotensin II, noradrenaline, arginine-vasopressin, and serotonin and blood pressure change following indomethacin, an inhibitor of cyclooxygenase, were examined in conscious sheep, before and during the development of cyclosporin A-induced hypertension. Cyclosporin caused an increase in mean blood pressure from 68 +/- 2 to 82 +/- 3 mm Hg (p less than 0.001) and in heart rate from 67 +/- 4 to 91 +/- 4 beats/min (p less than 0.001). Pressor and heart rate responses to all substances tested were not changed by cyclosporin treatment suggesting that changes in pressor responsiveness are unlikely to be involved in the development of cyclosporin hypertension in sheep.

Angiotensin II↗

PubMed1988

Dihydrocyclosporin D in sheep: haemodynamic and renal effects.

1. This study was designed to test the haemodynamic and renal effects in sheep of dihydrocyclosporin D (dCyD), an immunosuppressant agent derived from the fungus Tolypocladium inflatum Gams. 2. dCyD was infused for 5 days at 12 mg/kg per day. Mean arterial pressure (MAP) was elevated after 24 h, but thereafter returned to control levels. Heart rate was significantly elevated throughout the infusion and was still high 24 h postinfusion. Cardiac output rose after 5 days, but total peripheral resistance was unchanged during the infusion. 3. Glomerular filtration rate, renal blood flow and effective renal plasma flow remained unchanged, although urine sodium excretion rose for the first 48 h. 4. Infusion of the castor oil-based vehicle for cyclosporin, Cremaphore EL, for 5 days in four sheep did not produce any sustained changes in any of the parameters measured.

Animals↗

PubMed1987

Survival equations for red blood cells with statistical distributions in life spans.

The survival equations for labelled RBCs taking into account a hypothetical Gaussian (or binomial) statistical distribution for the life spans, with and without random destruction, have been derived in this paper. The numerical integration of these equations emphasises some particularities which will result from the existence of broad life span distributions. The differences between the results obtained with hypothetical populations of RBCs having statistical distributions for the life spans and hypothetical populations of RBCs with life spans equal to the distributions mean value for every cell are also discussed.

Erythrocyte Aging↗

PubMed1986

Dynamic imaging of the compliant perfusion of the lungs.

A method for the study of the dynamics of the perfusion of the compliant vascular tree of the lungs using in vivo labelled 99mTc red cells and ECG gating is presented. Following blood pool labelling, posterior, ECG gated gamma camera images were acquired in time intervals of about 40 ms for 1,000-2,000 cardiac cycles. The images show the lungs plus the heart and great vessels. The image sequence containing the periodic variation of the blood activity in the lungs during the cardiac cycle is analyzed to obtain volume curves and functional images of the amplitude and phase of the lung perfusion. The interference of the heart and great vessels with the left lung can be avoided by excluding the superimposed areas in the ROIs with the sacrifice of part of the left lung. This technique allows dynamic visualization of the perfusion process in the compliant arterial and venous vascular trees of the lungs. The results obtained with this method in normals and some pathologies are discussed.

Electrocardiography↗

PubMed1985

Renal gammagraphy with 99mTc-phosphomycin.

99mTc-Phosphomycin, a new radiopharmaceutical for kidney visualization, was used for animal experiments and tests of 171 patients. The results confirmed the usefulness of this product. The ease and yield of the labelling procedure, the low cost of the product, the excellent quality of the images and the functional information obtained showed that the use of 99mTc-phosphomycin as a radiopharmaceutical for kidney visualization has many advantages.

Adolescent↗

PubMed1983