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Biomedical subjects

J E Perez

Publications and source records attributed to J E Perez.

At least 19 recordsLinked to original sources
PubMed2001

Variation in patient management and outcomes for acute coronary syndromes in Latin America and North America: results from the Platelet IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) trial.

BACKGROUND: Although more than 9500 patients have been enrolled in major clinical trials in Latin America, practice patterns in this region have rarely been examined. We sought to compare characteristics, resource utilization, and outcomes of patients treated for acute coronary syndromes in Latin America with those in North America. METHODS: The Platelet IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Theraphy Trial (PURSUIT) enrolled 10,948 patients with non-ST-segment elevation acute coronary syndromes, including 585 in Latin America and 4358 in North America. We analyzed regional differences in patient groups, treatment patterns, and outcomes and used logistic regression analysis to identify association of enrollment region and survival. RESULTS: For patients in Latin America, the length of hospital stay was significantly longer (10 [7, 15] days vs 6 [4, 9], P <.001). Angiograms, angioplasty, and bypass surgery were significantly less common in Latin America (46.2%, 17.6%, and 11.3% vs 79.4%, 33.6%, and 19.4%, P <.001). Thirty-day death/myocardial infarction was not significantly higher, although mortality alone was significantly higher (6.8% vs 3.1%, P <.001). After adjustment for baseline characteristics, enrollment in Latin America remained an independent predictor for death at 30 days (odds ratio [OR] [95% confidence interval (CI)] 2.42 [1.60-3.67]) and persisted at 6 months (OR [95% CI] 2.5 [1.8-3.4]). CONCLUSIONS: Latin American patients treated for acute coronary syndromes were managed less invasively and were twice as likely as their North American counterparts to die within 6 months. This mortality difference was not explained by imbalances in baseline risk.

Angina, Unstable↗
PubMed2001

Effects of aging on left atrial reservoir, conduit, and booster pump function: a multi-institution acoustic quantification study.

OBJECTIVE: To assess the feasibility of measuring left atrial (LA) function with acoustic quantification (AQ) and then assess the effects of age and sex on LA reservoir, conduit, and booster pump function. PATIENTS AND SETTING: 165 subjects without cardiovascular disease, 3-79 years old, were enrolled by six tertiary hospital centres. INTERVENTIONS: Continuous LA AQ area data were acquired and signal averaged to form composite waveforms which were analysed off-line. MAIN OUTCOME MEASURES: Parameters of LA performance according to age and sex. RESULTS: Signal averaged LA waveforms were sufficiently stable and detailed to allow automated analysis in all cases. An age related increase in LA area was noted. LA reservoir function did not vary with age or sex. All parameters of LA passive and active emptying revealed a significant age dependency. Overall, the passive emptying phase accounted for 66% of total LA emptying ranging from 76% in the youngest to 44% in the oldest decade. LA contraction accounted for 34% of atrial emptying in all subjects combined with the older subjects being more dependent on atrial booster pump function. When adjusted for atrial size, there were no sex related differences in LA function. CONCLUSIONS: LA reservoir, conduit, and booster pump function can be assessed with automated analysis of signal averaged LA area waveforms. As LA performance varies with age, establishment of normal values should enhance the evaluation of pathologic states in which LA function is important.

Acoustics↗
PubMed2001

Domestic and peridomestic transmission of American cutaneous leishmaniasis: changing epidemiological patterns present new control opportunities.

Predictions that deforestation would reduce American cutaneous leishmaniasis incidence have proved incorrect. Presentations at a recent international workshop, instead, demonstrated frequent domestication of transmission throughout Latin America. While posing new threats, this process also increases the effectiveness of vector control in and around houses. New approaches for sand fly control and effective targeting of resources are reviewed.

Animals↗
PubMed2000

Factor structure of the Beck Depression Inventory-Second Edition (BDI-II) in a student sample.

A confirmatory factor analysis was performed to evaluate the factorial validity of the Beck Depression Inventory-Second Edition (BDI-II) in a large sample of undergraduates (N = 576). Results suggest that the revised measure is internally consistent and consists of two underlying factors assessing cognitive-affective and somatic symptoms of depression. Results support the use of the BDI-II as a severity measure of symptoms of depression.

Adolescent↗
PubMed1999

Molecular analysis of chronic granulomatous disease caused by defects in gp91-phox.

Chronic granulomatous disease (CGD) is an uncommon inherited disorder of phagocytic cells in which a defective respiratory burst leads to severe recurrent bacterial and fungal infections. The disease is a consequence of mutations in one of the four molecules that constitute the NADPH oxidase system of electron transport, whose most critical component is an unusual flavocytochrome b localized in the plasma and specific granule membranes. Mutations in the CYBB gene (localized in the short arm of the X chromosome) encoding the beta-subunit of this flavocytochrome (gp91-phox), which is are responsible for 60-65% of all cases of CGD. In this paper, we report the molecular characterization of seven unrelated kindreds native from Colombia and Brazil with CGD caused by gp91-phox deficiency. The exons with the possible mutation were identified by single-strand conformational polymorphism (SSCP) of genomic DNA and then confirmed by DNA sequencing. In one patient we found a substitution of A to G in the penultimate nucleotide of intron 12 (IVS12-2A-->G). In four other cases, four different nonsense mutations were detected: R91X, W106X, R157X, and R290X and the other two patients showed missense substitutions: E225V and C244Y. In six of these kindreds, all mothers were carriers but one that did not present any change in the gp91-phox gene, which indicates a de novo mutation in this kindred. Then, these family-specific mutations in gp91-phox produce different structural defects that alter the expression or function of an essential component of phagocyte oxidase.

Adolescent↗
PubMed1998

Phase III multicenter trial comparing the efficacy of 2% dodecafluoropentane emulsion (EchoGen) and sonicated 5% human albumin (Albunex) as ultrasound contrast agents in patients with suboptimal echocardiograms.

OBJECTIVES: This study was performed to compare the safety and efficacy of intravenous 2% dodecafluoropentane (DDFP) emulsion (EchoGen) with that of active control (sonicated human albumin [Albunex]) for left ventricular (LV) cavity opacification in adult patients with a suboptimal echocardiogram. BACKGROUND: The development of new fluorocarbon-based echocardiographic contrast agents such as DDFP has allowed opacification of the left ventricle after peripheral venous injection. We hypothesized that DDFP was clinically superior to the Food and Drug Administration-approved active control. METHODS: This was a Phase III, multicenter, single-blind, active controlled trial. Sequential intravenous injections of active control and DDFP were given 30 min apart to 254 patients with a suboptimal echocardiogram, defined as one in which the endocardial borders were not visible in at least two segments in either the apical two- or four-chamber views. Studies were interpreted in blinded manner by two readers and the investigators. RESULTS: Full or intermediate LV cavity opacification was more frequently observed after DDFP than after active control (78% vs. 31% for reader A; 69% vs. 34% for reader B; 83% vs. 55% for the investigators, p < 0.0001). LV cavity opacification scores were higher with DDFP (2.0 to 2.5 vs. 1.1 to 1.5, p < 0.0001). Endocardial border delineation was improved by DDFP in 88% of patients versus 45% with active control (p < 0.001). Similar improvement was seen for duration of contrast effect, salvage of suboptimal echocardiograms, diagnostic confidence and potential to affect patient management. There was no difference between agents in the number of patients with adverse events attributed to the test agent (9% for DDFP vs. 6% for active control, p = 0.92). CONCLUSIONS: This Phase III multicenter trial demonstrates that DDFP is superior to sonicated human albumin for LV cavity opacification, endocardial border definition, duration of effect, salvage of suboptimal echocardiograms, diagnostic confidence and potential to influence patient management. The two agents had similar safety profiles.

Adult↗
PubMed1998

Effects of myocardial fiber orientation in echocardiography: quantitative measurements and computer simulation of the regional dependence of backscattered ultrasound in the parasternal short-axis view.

We measured the regional disparity in backscattered ultrasound by means of obtaining integrated backscatter images of 10 healthy subjects and placing a region of interest in 18 distinct positions. A computer model simulating the short-axis view was implemented on the basis of previously measured values for the anisotropic ultrasonic properties of myocardium. Measurements showed that the integrated backscatter value was greatest for the anterior septum and decreased by 15.9 +/- 3.5 dB for the lateral wall and 17.7 +/- 3.5 dB for the inferior septum. The value in the posterior wall was 8.1 +/- 3.8 dB below the value for the anterior septum. The regional variation of backscatter predicted with the simulation correlated well with the clinical measurements. These results suggested that analyses based on measurements of backscatter may require compensation for the inherent anisotropic properties of myocardium.

Adult↗
PubMed1998

Double modulation of 5-fluorouracil by methotrexate and high-dose L-leucovorin in advanced colorectal cancer.

A phase II trial was performed to evaluate the efficacy and toxicity of a double modulation of 5-fluorouracil (5-FU) by methotrexate (MTX) and L-leucovorin (L-LV) in patients with advanced recurrent (inoperable) or metastatic colorectal carcinoma (ACC). Between July 1993 and October 1995, 41 patients with ACC received a regimen that consisted of MTX 150 mg/m2 i.v., infused over a 20-minute period at hour 0, followed 19 hours later by L-LV 250 mg/m2 in a 2-hour i.v. infusion. 5-FU, 900 mg/m2, was administered by i.v. push injection at hour 20. Beginning 24 hours after MTX administration, all patients received four doses of L-LV, 15 mg/m2 i.m., every 6 hours. Cycles were repeated every 15 days. Two patients were not assessable for response. Objective regression was observed in 11 of 39 (28%) patients, [95% confidence interval (CI), 14-42%]. One (2%) patient achieved complete response (CR) and 10 (26%) partial response (PR). No change was recorded in 15 (39%) patients and progressive disease was noted in 13 (33%) patients. The median time to treatment failure was 6 months and the median survival time was 10 months. Toxicity was within acceptable limits, but one therapy-related death due to severe leukopenia was observed. The dose-limiting toxicity was mucositis. Eight episodes of grade 3 or 4 stomatitis were observed, and were responsible for dosage modifications of MTX and 5-FU. In conclusion, further in experimental and clinical studies are clearly necessary in order to design the best modulatory strategy of 5-FU.

Adult↗
PubMed1998

Effects of tissue anisotropy on the spectral characteristics of ultrasonic backscatter measured with a clinical imaging system.

In this paper, we report the effects of inherent tissue anisotropy on the spectral properties of backscattered ultrasound when measured with a commercially-available imaging system. We insonified five specimens of bovine tendon immersed in a water tank and rotated in 10 degrees increments while being imaged with a Hewlett-Packard Sonos 1500 system. The backscattered RF signals corresponding to each angle of insonification were digitized and the spectral characteristics of the backscattered ultrasound were determined. The mean anisotropy, defined as the average difference between values at perpendicular and parallel insonification, for band-limited estimates of backscattered power, centroid frequency, upper-band to lower-band power ratio, and upper-band to total-band power ratio were found to be 24.6 +/- 1.1 dB, 142 +/- 27 kHz, 32 +/- 13%, and 22 +/- 5%, respectively (mean +/- SE). The magnitude of each of these backscatter spectral parameters was larger at perpendicular insonification compared with the corresponding values at parallel insonification, consistent with previous measurements of the inherent anisotropy of ultrasonic attenuation and backscatter in tissue.

Animals↗
PubMed1997

Comparison of integrated backscatter values obtained with acoustic densitometry with values derived from spectral analysis of digitized signals from a clinical imaging system.

Time-domain-based integrated backscatter values obtained with the use of acoustic densitometry (AD) were compared with values determined from a spectral-based analysis of the radio-frequency (RF) signals with a modified Hewlett-Packard Sonos 1500 imaging system. Integrated backscatter images of five specimens of bovine tendon were acquired in the AD acquisition mode, and the corresponding signals related to the backscattered RF were digitized for each angle of insonification as the specimens were rotated in 10-degree increments. The integrated backscatter images were analyzed with the AD analysis package, and the corresponding values determined from the RF power spectra were obtained from the digitized ultrasonic signals. Good agreement was found between the two methods over the entire range of measured values. The mean anisotropy in the measured integrated backscatter (mean +/- standard error) was found to be 27 +/- 2 dB for time-domain-based analysis and 25 +/- 2 dB for RF spectral-based analysis.

Acoustics↗
PubMed1997

Anisotropy of the apparent frequency dependence of backscatter in formalin fixed human myocardium.

Measurements of the frequency dependence of ultrasonic backscatter are presented for specific angles of insonification for regions of infarcted and noninfarcted human myocardium. A 5-MHz transducer was used to insonify cylindrical cores taken from 7 noninfarcted regions and 12 infarcted regions of the left ventricular free wall of 6 formalin-fixed human hearts explanted because of ischemic cardiomyopathy. The dependence of apparent (uncompensated for diffraction effects and attenuation) backscatter on frequency was approximated by a power-law dependence, magnitude of B(f)2 = afn. Under ideal conditions in a lossless medium, the effect of not compensating for the effects of diffraction and attenuation leads to the value of n to be 2.0 for Rayleigh scatterers while the frequency dependence of the fully compensated backscatter coefficient would be f4. The value of n was determined over the frequency range, 3-7 MHz. Both nonifarcted and infarcted myocardium exhibited anisotropy of the frequency dependence of backscatter, with maxima occurring at angles that were perpendicular to the predominant myofiber direction and minima when parallel to the fibers. Perpendicular insonification yielded results for n of 1.8 +/- 0.1 for noninfarcted myocardium and 1.2 +/- 0.1 for infarcted myocardium while parallel insonification yielded results of 0.4 +/- 0.1 for noninfarcted and 0.0 +/- 0.1 for infarcted myocardium. The functional form of the angle-dependent backscatter is similar for both noninfarcted and infarcted myocardium, although the frequency dependence is clearly different for both tissue states for all angles of insonification. The results of this study indicate that the anisotropy of the frequency dependence of backscatter may play a significant role in ultrasonic imaging and is an important consideration for ultrasonic tissue characterization in myocardium.

Anisotropy↗
PubMed1997

Vinorelbine as neoadjuvant chemotherapy in advanced cervical carcinoma.

PURPOSE: To evaluate the efficacy and toxicity of vinorelbine (VNB) as single-agent neoadjuvant chemotherapy in advanced cervical carcinoma (ACC). PATIENTS AND METHODS: Between December 1993 and October 1995, 43 untreated patients with stages IIB to IVA squamous cell cervical cancer were entered onto this study. Forty-two patients are assessable for response and 43 for toxicity. The median age was 46 years (range, 28 to 65). Distribution by stages (International Federation of Gynecology and Obstetrics [FIGO]) was as follows: IIB, 18 patients; IIIA, one; IIIB, 19; and IVA, five. Therapy consisted of VNB 30 mg/m2 by 20-minute intravenous (IV) infusion repeated weekly for 12 injections and followed by radical surgery if feasible or definitive radiotherapy. Both staging and response assessment were performed by a multidisciplinary team. RESULTS: One patient was considered not assessable for response. A total of 493 cycles of therapy were administered and objective remissions were observed in 19 of 42 patients (45%; 95% confidence interval, 30% to 60%). Two patients (5%) had a complete response (CR) and 17 (40%) a partial response (PR); no change (NC) was observed in 16 (38%) and progressive disease (PD) in seven (17%). Six of 19 patients (32%) who achieved objective responses (ORs) underwent surgery. The median time to failure and median survival time have not been reached yet. There were no therapy-related deaths. The dose-limiting toxicity was myelosuppression. Leukopenia occurred in 35 patients (81%) and was grade 3 or 4 in seven (17%). Twelve patients (28%) developed peripheral neuropathy, while myalgias occurred in 10 (23%). Constipation was observed in nine patients (21%), one with a prolonged ileum. Phlebitis was recorded in 18 patients (41%). In contrast, emesis and mucositis were rarely observed. No patient developed alopecia grade 3. By the end of the twelfth course of treatment, the average received dose-intensity was 85.4% of that projected. CONCLUSION: VNB is an active drug against ACC with moderate toxicity. Its activity is among the highest reported for single agents. Further evaluation in association with other agents is clearly justified.

Adult↗
PubMed1997

Cardiac and glycemic benefits of troglitazone treatment in NIDDM. The Troglitazone Study Group.

Troglitazone is a thiazolidinedione under development for the treatment of NIDDM and potentially other insulin-resistant disease states. Treatment with troglitazone is associated with an improvement in hyperglycemia, hyperinsulinemia, and insulin-mediated glucose disposal. No significant side effects have been observed in humans. Because of reported cardiac changes in animals treated with drugs of this class, this multicenter 48-week study was conducted to evaluate whether NIDDM patients treated with troglitazone develop any cardiac mass increase or functional impairment. A total of 154 NIDDM patients were randomized to receive troglitazone 800 mg q.d. or glyburide titrated to achieve glycemic control (< or =20 mg b.i.d. or q.d.). Two-dimensional echocardiography and pulsed Doppler were used to measure left ventricular mass index (LVMI), cardiac index (CI), and stroke volume index (SVI). All echocardiograms were performed at each center (baseline, 12, 24, 36, and 48 weeks), recorded on videotape, and forwarded to a blinded central echocardiographic interpreter for analysis. The results showed that LVMI of patients treated with troglitazone was not statistically or clinically different from baseline after 24 or 48 weeks. Statistically significant increases in SVI and CI and a statistically significant decrease in diastolic pressure and estimated peripheral resistance were observed in troglitazone-treated patients. These results were not sex-specific. Glycemic benefits of troglitazone treatment were observed as evidenced by long-term improvement of HbA1c and C-peptide levels. Furthermore, triglycerides were significantly lower, and HDL was significantly higher at weeks 24 and 48. In conclusion, NIDDM patients treated with troglitazone do not show any cardiac mass increase or cardiac function impairment. Conversely, patients on troglitazone benefited from enhanced cardiac output and stroke volume, possibly as a result of decreased peripheral resistance. Treatment with troglitazone appears to have a favorable impact on known cardiovascular risk factors and could potentially lower cardiovascular morbidity in NIDDM patients.

Blood Glucose↗
PubMed1997

Delayed tension pneumothorax after laparoscopy.

Laparoscopy is a safe and useful procedure in evaluating intraabdominal disease. Serious complications have been reported but are rare. Laparoscopy related pneumothorax is one such complication that may occur during the procedure or in the immediate period thereafter. This complication is typically neither hemodynamically significant nor tension in nature. We report the unique case of a 52-year-old woman who not only developed acute respiratory compromise from a tension pneumothorax but did so 3 h after the completion of a seemingly uneventful laparoscopic procedure. Prompt recognition of this potential complication may permit immediate and effective treatment of this life-threatening complication.

Female↗
PubMed1996

Delineation of myocardial stunning and hibernation by positron emission tomography in advanced coronary artery disease.

With positron emission tomography, the resting flow abnormalities underlying reversible left ventricular dysfunction in 17 patients with chronic coronary artery disease were delineated. The level of flow in reversible dysfuncTional segments (i.e., those demonstrating improvement after revascularization) was markedly variable, ranging from 0.32 to 1.25 ml/gm/min. In 20 of these segments, flow was preserved, whereas in 12 segments, flow was reduced, when compared with that in, age-matched controls. Preservation of flow was associated with preservation of myocardial oxygen consumption and no alterations in myocardial substrate use. In contrast, a reduction in flow resulted in a decrease myocardial oxygen consumption and an increase in myocardial glucose use. Thus resting reversible left ventricular dysfunction in patients with chronic coronary artery disease can reflect a diversity of resting flow abnormalities. Moreover, myocardial perfusion at rest is frequently within normal limits, suggesting that the reversible mechanical dysfunction in these patients is attributable to intermittent myocardial stunning and not hibernation.

Adult↗
PubMed1996

Ifosfamide and vinorelbine as first-line chemotherapy for metastatic breast cancer.

PURPOSE: To evaluate the efficacy and toxicity of the combination of ifosfamide (IFX) and vinorelbine (VNB) as first-line chemotherapy in metastatic breast cancer (MBC). PATIENTS AND METHODS: Between August 1993 and August 1995, 45 patients with untreated MBC received a regimen that consisted of IFX 2 g/m2 by 1-hour intravenous (i.v.) infusion on days 1 to 3, mesna 400 mg/m2 by i.v. bolus at hours 0 and 4 and 800 mg/m2 orally at hour 8 on days 1 to 3, and VNB 35 mg/m2 by 20-minute i.v. infusion on days 1 and 15. Courses were repeated every 28 days. During the first course only, half-dose VNB (17.5 mg/m2) was administered on days 8 and 22. The median age was 53 years and 30 patients (67%) were postmenopausal. Dominant sites of disease were soft tissue in nine patients, bone in seven, and visceral in 29. RESULTS: Objective responses (ORs) were recorded in 25 of 43 assessable patients (58%; 95% confidence interval, 43% to 73%). Complete remissions (CRs) occurred in six patients (14%) and partial remissions (PRs) in 19 (44%). No change (NC) was recorded in 10 patients (23%) and progressive disease (PD) in eight patients (19%). The median time to treatment failure was 12 months and the median survival duration 19 months. Myelosuppression was the limiting toxicity, mainly leukopenia in 32 patients (74%). In contrast, anemia and thrombocytopenia were mild. Other significant toxicities included peripheral neuropathy in nine patients (21%), constipation in 15 (35%), and myalgias in 11 (26%). CONCLUSION: IFX/VNB is an active combination against MBC with moderate toxicity and deserves further evaluation.

Adult↗
PubMed1995

Intravenous albunex during dobutamine stress echocardiography: enhanced localization of left ventricular endocardial borders.

Albunex is an intravenous contrast agent that opacifies the left ventricle (LV). This study evaluated the effect of Albunex on the enhancement of LV endocardial border localization during dobutamine stress echocardiography (DSE). Albunex was infused in 30 patients at baseline and with low- and high-dosage dobutamine. Apical two- and four-chamber views were divided into six segments each, and enhancement of LV border localization was compared with precontrast images graded as follows: 0 = none; 1 = faint; or 2 = optimal. The mean grade and percentage of segments with optimal localization of LV endocardial borders were determined. There was a significant increase in enhancement with low- and high-dosage dobutamine when compared with baseline. Of 179 segments with suboptimal enhancement at baseline, 137 (77%) became optimal during DSE with Albunex. We conclude that Albunex improves localization of LV endocardial borders and that this localization is enhanced during DSE.

Aged↗