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Biomedical subjects

R Tello

Publications and source records attributed to R Tello.

At least 19 recordsLinked to original sources
PubMed2004

Chronic cyclosporine-induced nephrotoxiciy in heart transplant patients: long-term benefits of treatment with mycophenolate mofetil and low-dose cyclosporine.

BACKGROUND: Cyclosporine-induced nephropathy is a major limitation in heart transplant patients. Cyclosporine dose reduction may lead to substantial early improvement in renal function. Our aim was to study the long-term benefits of therapy with low doses of cyclosporine plus mycophenolate mofetil in heart transplant patients with drug-induced nephrotoxicity. METHODS: Twenty-five adult heart transplant patients with cyclosporine-related nephrotoxicity (mean posttransplant = 41.7 +/- 25.7 months) were included in the retrospective analysis (22 men, mean age = 58.8 +/- 7.9 years.). Patients were switched from azathioprine to mycophenolate mofetil (1 to 3 g/d), followed by a stepwise reduction in cyclosporine dosage (trough cyclosporine level maintained around 100 ng/mL). Renal function was determined by serial measurements of serum creatinine and glomerular filtration rate at 3-month intervals. RESULTS: With a mean follow-up of 30 +/- 13 months, the baseline creatinine of 2.37 +/- 0.5 mg/dL decreased to 1.59 +/- 0.40 mg/dL (P < .0001). The baseline glomerular filtration rate of 36.77 +/- 10.10 mL/min improved to 54.98 +/- 13.80 mL/min (P < .0001). The cyclosporine level was the unique independent variable associated with renal functional improvement (partial R(2) = 0.4). Within the first 3 months, renal function displayed a rapid improvement after conversion to mycophenolate mofetil (P < .001), reaching a plateau, without further significant improvement over the course of time. CONCLUSIONS: Cyclosporine-induced nephrotoxicity is not a progressive, irreversible disease. Reduction in cyclosporine exposure by addition of mycophenolate mofetil is useful to achieve long-term renal functional improvement, thereby avoiding chronic renal failure. A unique, significant factor associated with this improvement was the reduction in cyclosporine level.

Adult↗
PubMed2001

Impact of mild pulmonary hypertension on mortality and pulmonary artery pressure profile after heart transplantation.

BACKGROUND: Pulmonary hypertension is a risk factor for early mortality after transplantation, but the risk threshold is debated. Also, little is known about the evolution of pulmonary circulation after transplantation. The aim of this study was to determine the influence of current risk pulmonary pressure parameters on early post-operative mortality and to assess the time-related changes in pulmonary pressure after surgery. METHODS: One hundred twelve consecutive transplanted patients were studied retrospectively to determine the influence of trans-pulmonary gradient of >12 mm Hg and pulmonary vascular resistance of >2.5 Wood units, at baseline or after vasodilator test, on early mortality. A multivariate analysis was used to study the hemodynamic parameters associated with early mortality. The pulmonary pressures of all surviving patients were studied for up to 3 years after surgery. RESULTS: Early mortality in the groups with and without pulmonary hypertension were 24.4% and 5.6%, respectively (p =.009). The only variable that was independently associated with early mortality was the pulmonary vascular resistance index (odds ratio = 1.459). Mild pulmonary hypertension disappeared 1 year after heart transplantation. CONCLUSIONS: Mild pulmonary hypertension is a risk factor for early postoperative mortality. The hemodynamic parameter most closely associated with early mortality is pulmonary vascular resistance index. The hemodynamic profile of pulmonary circulation after heart transplantation is partially dependent on the level of pulmonary hypertension before transplantation, at least during the first year after surgery.

Adolescent↗
PubMed2001

Incidence of adrenal masses in patients referred for renal artery stenosis screening MR.

RATIONALE AND OBJECTIVES: Prior work has shown the efficacy of magnetic resonance (MR) in renal artery stenosis evaluation. The increasing role of renal artery stenosis in the differential diagnostic evaluation of hypertension raises the question of whether MR should be used as a screening modality. This project evaluated the additional potential benefits of MR by determining the incidence of adrenal masses in this selected population. METHODS: A 2-year retrospective study analysis of patients who failed to respond to antihypertensive medical management and were referred for renal MR for hypertension amassed 77 subjects ranging in age from 18 to 88 years. A masked analysis for adrenal masses was performed on this data set. Magnetic resonance techniques included T2-weighted turbo spin-echo (repetition time [TR] 2000-4000 ms, echo time [TE] 80-100 ms, turbo factor 2-16), T1-weighted spin-echo (TR 200-500 ms, TE 10-30 ms), gradient-echo time-of-flight (TR 26 ms, TE 6.9 ms, 40 degrees flip angle, 2 excitations), and dynamic gadopentetate dimeglumine-enhanced MR angiography (three-dimensional gradient recalled echo, TR 10 ms, TE 3 ms, 40 degrees flip angle, 1 excitation). RESULTS: Thirty-three patients had renal artery disease, 44 had normal renal arteries, and 7 had adrenal masses. Forty-three percent of patients who underwent renal MR had disease of the renal arteries detected, and 9% of patients referred for MR had adrenal masses that would have been missed with scintigraphy and/or angiography, of which 57% were responsible for hypertension. CONCLUSIONS: The ability to evaluate renal artery and adrenal anatomy globally can be useful, as exemplified in the current series, and the adrenals should be examined carefully in any renal MR in a hypertensive patient.

Adolescent↗
PubMed2001

Prediction rule for characterization of hepatic lesions revealed on MR imaging: estimation of malignancy.

OBJECTIVE: Our aims were to establish factors that are most predictive of hepatic lesion malignancy and to formulate a prediction rule. MATERIALS AND METHODS: A cross-sectional study of 227 abdominal MR imaging examinations revealed 85 lesions in 67 patients (29 men, 38 women; age range, 29-78 years; mean age, 51.4 years) who were being examined for primary malignancy (n = 42) or unknown lesion characterization (n = 25). All were referred for MR imaging after CT or sonography. Patient demographics (age, sex, history of malignancy), lesion size and morphology, quantitative T2 calculation, and pattern of enhancement on gadopentetate dimeglumine administration were evaluated for predictive ability. RESULTS: Thirty-two liver lesions were malignant (eight colon cancer, five breast cancer, four cervical cancer, three renal cancer, three lung cancer, and nine miscellaneous cancers), 53 were benign (37 hemangiomas, 15 cysts, and one focal nodular hyperplasia). Calculated T2 relaxation times (mean +/- standard deviation [SD]) were as follows: malignant tumors (91.72 +/- 21.9 msec), hemangiomas (136.1 +/- 26.3 msec), cysts (284.1 +/- 38.2 msec) (p < 0.001). Logistic regression analysis indicated that lesion size and sex and age of patient were not significant independent predictors (p > 0.05). However, the combination of a history of malignancy, T2 value, and gadopentetate dimeglumine-enhancement pattern allowed generation of a prediction rule with an area under the receiver operating characteristic curve of 0.95. The patient's weight, lesion morphology, and cell type of the primary malignancy did not provide additional predictive information (p > 0.2). CONCLUSION: We recommend using the combination of T2 quantification and patient history of malignancy before deciding to administer gadopentetate dimeglumine for optimal lesion characterization, especially for equivocal lesions with T2 values between 90 and 130 msec. These factors allowed the construction of a prediction rule for lesion characterization.

Adult↗
PubMed2000

World Wide Web program for optimizing and assessing medical student performance during the radiology clerkship.

RATIONALE AND OBJECTIVES: The purpose of this study was to adapt the technology of the World Wide Web to the teaching and evaluation of medical students participating in the radiology clerkship at our institution. MATERIALS AND METHODS: Teaching modules were placed on a local intranet site. One hundred two student evaluations were conducted online as a standardized, written- and image-based test that was administered both before and after the clerkship. The computer-delivered test consisted of 40 standardized questions that were sorted by category (based on American College of Radiology code criteria) and randomly administered from a pool of 200 potential questions. Scores from before and after the clerkship were analyzed statistically to evaluate the effectiveness of the educational program and the student performance. Student case presentation scoring and clerkship administration tasks were also evaluated both before and after implementation of the modules during the first 12 months of this project (July 1997 to July 1998). RESULTS: A statistically significant (P < .001) improvement in test performance was found in 102 consecutive students, and all 102 students (100%) preferred the digital-testing format. The amount of time needed to tabulate the teacher evaluation, grade the test, and score the oral presentations decreased substantially with the digital system. CONCLUSION: An intranet-based method of evaluating students in an ongoing fashion allows for additional growth in content and ease of use during the radiology clerkship.

Attitude to Computers↗
PubMed2000

MR imaging of renal masses interpreted on CT to be suspicious.

OBJECTIVE: Prior studies have shown that renal MR contrast enhancement improves the efficacy of mass and proximal vascular evaluation. This study assessed the usefulness of different sequences for characterization of masses that appeared suspicious on CT and for prediction of their potential for malignancy. SUBJECTS AND METHODS: In a prospective manner 32 patients (age range, 26-78 years: average age, 54 years), each with at least one suspicious mass on CT, were examined with MR imaging. The following sequences were performed: conventional spin-echo with and without fat saturation, fast spin-echo, and dynamic gadopentetate dimeglumine-enhanced infusion using a 1.5-T superconducting magnet. Results were analyzed and compared with pathologic results after resection. RESULTS: A total of 65 renal masses of average size 2.6 cm (range, 1-10 cm) were detected with dynamic MR imaging. Seventeen of the 65 masses were malignant. Of the 17 malignant masses, three did not enhance on dynamic MR imaging (because of hemorrhage). Sixteen of the 17 malignant masses were heterogeneous on T2-weighted images. Three enhancing masses contained fat and all were angiomyolipomas. Thirty-five of the 65 masses (four with hemorrhage) did not show enhancement, all of which were homogeneous on T2-weighted images and were proven to be cysts. Five masses resulted from infections and had heterogeneous T2 appearance. The remaining masses were three hematomas with hemorrhage, one column of Bertin, and one aneurysm. CONCLUSION: Renal masses that are interpreted as suspicious on CT may lack MR enhancement because of hemorrhage effects; heterogeneity of their T2 appearance is thus critical in differentiating malignancy from benign disease. Odds-ratio calculations give an adjusted estimate of a 3.36-fold increase (95% confidence interval, 1.8-6.27) in the likelihood of malignancy when masses are heterogeneous on T2-weighted images and a 29-fold increase (95% confidence interval, 3.67-241.8) for predicting malignancy when enhancement is present.

Adult↗
PubMed2000

The virtual course: delivery of live and recorded continuing medical education material over the Internet.

OBJECTIVE: Our objective was to deliver live and recorded lectures from a continuing medical education course, including the representations of original slides, over the Internet, using streaming audio media. CONCLUSION: The streaming audio media, an emerging technology, not only delivers large lectures over the Internet using commercially available PCs and modems, but also allows review at any time by individuals with access to the Web. An interactive conference of continuing medical education curriculum can thus be delivered and continuing medical education credit earned without leaving home.

Education, Distance↗
PubMed1999

Interventional catheter magnetic resonance angiography with a conventional 1.5-T magnet: work in progress.

Magnetic resonance contrast enhancement depends on the relative timing of image acquisition. Limited human trials have demonstrated efficacy of intra-arterial gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) in delineating vascular anatomy with X-rays. The present study assessed the ability of dynamic MR during intra-arterial Gd-DTPA administration to demonstrate vascular anatomy compared to conventional angiography as the gold standard. As interventional MR techniques using dedicated magnets proliferate, the ability to perform invasive MR angiography with a conventional magnet would be of great utility at established sites. Four subjects referred for different types of angiography underwent dynamic MR studies, including one with iliac artery stenting (Palmaz P204, Johnson and Johnson). All were examined with conventional angiography, and again after dynamic intra-arterial (IA) Gd-DTPA infusion. Coronal MRI images of the body were acquired using a 1.5-T superconducting magnet (three with a GE Signa, one with Philips NT), fast spoiled gradient echo (FSPGR); echo time (TE) = 4.2 msec, repetition time (TR) = 68-150 msec, flip = 75 degrees, 0-600 s after dilute Gd-DTPA IA bolus injection during sequential breath-hold acquisitions of 13-32 s each. All arteries were detected with dynamic MR. The FSPGR MRI with IA Gd-DTPA administration can provide adequate time and spatial resolution to demonstrate arterial anatomy and arterial stent patency.

Carotid Artery Diseases↗
PubMed1999

Strongyloides stercoralis hyperinfection associated with human T cell lymphotropic virus type-1 infection in Peru.

A study was conducted in Lima, Peru to determine if patients with Strongyloides hyperinfection had human T cell lymphotropic virus type-1 (HTLV-I) infection. The study included patients with Strongyloides hyperinfection and a control group consisted of sex- and age-matched asymptomatic healthy individuals whose stools were negative for Strongyloides. A third group included patients with intestinal strongyloidiasis. Sera from each study subject were tested for HTLV-1/2I by an ELISA and Western blot. The HLTV-1 infection rates (85.7%, 18 of 21) were significantly (P < 0.001) associated with Strongyloides hyperinfection compared with the control group (4.7%, 1 of 21). The HTLV-1 rate (10%, 6 of 62) for patients with intestinal strongyloidiasis was significantly (P < 0.001) lower than patients with Strongyloides hyperinfection, but did not differ significantly (P > 0.05) from the control group. The association of HTLV-1 infection was observed among 17 of 19 patients more than 20 years of age and one of two younger patients. None had HTLV-2 infection. In conclusion, Strongyloides hyperinfection among Peruvian patients was highly associated with HTLV-1 infection.

Adult↗
PubMed1999

Use of three-dimensional MR angiography for tracking a contrast bolus in the carotid artery.

Contrast-bolus tracking in the carotid bifurcation was accomplished using an MR angiographic technique with a 3D turbo field-echo readout (TR/TE = 6/3, flip angle = 50 degrees) modified by a keyhole scheme. Optimal visibility of the contrast bolus was achieved by digital subtraction from a reference volume. This technique reliably time-resolves the carotid arteries from the jugular veins.

Adult↗
PubMed1998

Meta analysis of the relationship between tuberous sclerosis complex and renal cell carcinoma.

The association of angiomyolipoma with tuberous sclerosis complex (TSC) patients is well recognised. Some literature has suggested that patients with TSC are at increased risk of renal neoplasm, particularly since angiomyolipomas can be locally invasive and demonstrate tumor like neovascularity on angiography. In an attempt to place in context one case of metastatic renal cell carcinoma in a patient with TSC a meta analysis of the literature was performed. One pediatric patient with TSC and metastatic renal cell carcinoma was evaluated. Reviews and case reports of TSC and renal cell carcinoma and related imaging findings were identified by searching the MEDLINE database, the 'bibliography of reviews' in Index Medicus, personal files and the reference lists from all identified reviews. Individual cases suitable for review in the available literature from 1922 through 1993 comprised the data base. The data base was analysed with the method of proportions and unpaired two-tailed Student's t-test for different populations. A cumulative summary of the literature amassed 107 additional cases from 62 reports over 71 years. Our case is the 17th case, to our knowledge, of renal cell carcinoma in TSC. Analysis of the distribution of characteristics and incidence of; renal cysts, renal cell carcinoma, and lymph node involvement demonstrate no increased risk of renal cell carcinoma in patients with TSC (P = NS). Though anecdotal evidence has suggested a relationship between TSC and renal cell carcinoma, meta analysis of cases of coincident TSC renal complex, cystic changes, angiomyolipoma and renal cell carcinoma implies an identical, though small, risk of malignancy in TSC patients as compared with the normal population.

Adolescent↗