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E Foster

Publications and source records attributed to E Foster.

At least 19 recordsLinked to original sources
PubMed2003

The new RENT family of repetitive elements in Nicotiana species harbors gene regulatory elements related to the tCUP cryptic promoter.

The tCUP cryptic constitutive promoter was discovered in the tobacco genome by T-DNA (transfer DNA) tagging with a promoterless GUS-nos gene. Here, we show that the portion of the tCUP sequence containing a variety of cryptic gene regulatory elements is related to a new family of moderately repetitive sequences (10(2) copies), the RENT (repetitive element from Nicotiana tabacum) family. The RENT family is found only in certain Nicotiana species. Five RENT elements were cloned and sequenced. The RENT elements are a minimum of 5 kb in length and share 80-90% sequence similarity throughout their length. The 5' termini are the same in the isolated RENT family members and are characterized by a conserved border sequence (TGTTGA(T or C)ACCCAATTTT(T or C)). The 3' ends of RENT sequence similarity vary in location and sequence. The tCUP cryptic promoter originated from a unique truncated RENT element that interrupts a phytochelatin synthase-like gene that may have undergone rearrangements prior to or resulting from T-DNA insertion. No evidence was found for expressed coding regions within the RENT elements; however, like the cryptic gene regulatory elements within the tCUP sequence, the isolated RENT elements possess promoter activity and translational enhancer activity.

Base Sequence↗
PubMed2001

Usefulness of stroke distance by echocardiography as a surrogate marker of cardiac output that is independent of gender and size in a normal population.

Left ventricular outflow tract stroke distance (SD) can be measured using pulsed-wave Doppler echocardiography, and is independent of body size. Moreover, persons with structurally normal hearts (heart rate < 55 beats/min) had SD > 0.18 m, and those with a heart rate > 95 beats/min had SD < 0.22 m; outside of these parameters, low- and high-output states are likely to exist, and suspicion of these can be confirmed by calculation of minute distance (normal range 9.7 to 20.5 m/min).

Adult↗
PubMed2001

Enhancers and core promoter elements are essential for the activity of a cryptic gene activation sequence from tobacco, tCUP.

Cryptic gene regulatory elements are sequences that are inactive at their native locations in the genome but have the ability to become functional when positioned adjacent to genes. We have recently isolated such a cryptic sequence from tobacco, tCUP, that can act as a promoter. A 135-bp fragment spanning extending from position -197 to -62, relative to the transcription start site, was found to promote GUS expression in all of the major organs of transgenic Arabidopsis plants. Furthermore, this 135-bp fragment complemented the -46 minimal promoter of CaMV 35S and conferred constitutive expression on transgenic Arabidopsis plants. An electrophoretic mobility-shift assay showed that nuclear proteins prepared from tobacco leaves interact with the 135-bp fragment. tCUP has a core promoter that lacks the TATA consensus sequence but addition of a TATA-box sequence increased the core promoter activity by three-fold. The sequence surrounding the transcription start site of tCUP has sequence similarity with the initiator element (Inr), and deletion of this sequence significantly reduced promoter activity, suggesting that an essential Inr element may exist in the tCUP core promoter. Fusion of the GCC-box enhancer element from pathogenesis-related genes to the core promoter elevated tCUP core promoter activity. Our study indicates that cryptic promoters are similar in composition and organization to promoters associated with expressed genes and that their promoter elements can be combined to create composite promoters that are fully functional. This data provides direct evidence that the expression pattern of plant genes can be influenced by cryptic gene regulatory elements when they are brought into juxtaposition with genes through DNA rearrangements.

Arabidopsis↗
PubMed2001

Non-diabetic relatives of Type 2 diabetic families: dietary intake contributes to the increased risk of diabetes.

AIMS: Non-diabetic first degree relatives of Type 2 diabetic patients are at increased risk of developing diabetes and cardiovascular disease. This is assumed to reflect a shared genetic predisposition. The aim of this study was to test the hypothesis that lifestyle factors, specifically dietary factors, are also important to the increased risk in non-diabetic relatives. METHODS: Dietary intake was assessed using a validated food frequency questionnaire in 149 non-diabetic first degree relatives (age 20-65 years) from families of North European extraction with two or more living Type 2 diabetic family members, and 143 age- and sex-matched control subjects from the background population with no family history of diabetes. RESULTS: Relatives reported higher absolute intakes of total fat (mean (95% confidence intervals) 83 (76-91) vs. 71 (66-76) g/day, P = 0.01), saturated fat (SFA; 39 (36-43) vs. 33 (30-36) g/day, P < 0.01) and cholesterol (391 (354-427) vs. 318 (287-349) mg/day, P < 0.01), and a lower intake of non-starch polysaccharide (P < 0.05). Considered as percentage of total daily energy intake, relatives had higher intakes of total fat (P < 0.01) and SFA (P < 0.02), and a lower intake of carbohydrate (P < 0.02). These differences remained after exclusion of suspected under- and over-reporters of dietary intake. CONCLUSIONS: Non-diabetic relatives of Type 2 diabetic patients were found to consume diets that will promote rather than prevent the development of diabetes and cardiovascular disease. This suggests that the increased risk to non-diabetic relatives is therefore not entirely genetic, and there is scope for decreasing the risk through lifestyle modification.

Adult↗
PubMed2001

LV systolic performance improves with development of hypertrophy after transverse aortic constriction in mice.

Transverse aortic constriction (TAC) is an effective technique for inducing left ventricular (LV) hypertrophy in mice. With the use of transthoracic echocardiography and Doppler measurements, we studied the effects of an acute increase in pressure overload on LV contractile performance and peak systolic wall stress index (WSI) at early time points after TAC and the time course of the development of LV hypertrophy in mice. The LV mass index was similar between TAC and sham-operated mice at postoperative day 1 but progressively increased in TAC mice by day 10. There was no further increase in the LV mass index between postoperative days 10 and 20. On day 1, whereas peak systolic WSI increased significantly, the LV ejection fraction (LVEF) and percent fractional shortening (%FS) decreased in TAC mice compared with sham-operated mice. By day 10, peak systolic WSI, LVEF, and %FS had recovered to baseline levels and were not significantly different between postoperative days 10 and 20. Thus LV systolic performance in mice declines immediately after TAC, associated with increased peak systolic WSI, but recovers to baseline levels with the development of compensatory LV hypertrophy over 10-20 days.

Animals↗
PubMed2000

Cardiovascular effects of 3,4-methylenedioxymethamphetamine. A double-blind, placebo-controlled trial.

BACKGROUND: The psychoactive stimulant 3, 4-methylenedioxymethamphetamine (MDMA), also known as "ecstasy," is widely used in nonmedical settings. Little is known about its cardiovascular effects. OBJECTIVE: To evaluate the acute cardiovascular effects of MDMA by using transthoracic two-dimensional and Doppler echocardiography. DESIGN: Four-session, ascending-dose, double-blind, placebo-controlled trial. SETTING: Urban hospital. PATIENTS: Eight healthy adults who self-reported MDMA use. INTERVENTION: Echocardiographic effects of dobutamine (5, 20, and 40 microg/kg of body weight per minute) were measured in a preliminary session. Oral MDMA (0.5 and 1.5 mg/kg of body weight) or placebo was administered 1 hour before echocardiographic measurements in three weekly sessions. MEASUREMENTS: Heart rate and blood pressure were measured at regular intervals before and after MDMA administration. Echocardiographic measures of stroke volume, ejection fraction, cardiac output, and meridional wall stress were obtained 1 hour after MDMA administration and during dobutamine infusions. RESULTS: At a dose of 1.5 mg/kg, MDMA increased mean heart rate (by 28 beats/min), systolic blood pressure (by 25 mm Hg), diastolic blood pressure (by 7 mm Hg), and cardiac output (by 2 L/min). The effects of MDMA were similar to those of dobutamine, 20 and 40 microg/kg per minute. Inotropism, measured by using meridional wall stress corrected for ejection fraction, decreased after administration of dobutamine, 40 microg/kg per minute, but did not change after either dose of MDMA. CONCLUSIONS: Modest oral doses of MDMA increase heart rate, blood pressure, and myocardial oxygen consumption in a magnitude similar to dobutamine, 20 to 40 microg/kg per minute. In contrast to dobutamine, MDMA has no measurable inotropic effects.

Administration, Oral↗
PubMed2000

Transesophageal echocardiography (TEE) in the evaluation of the coronary arteries.

With technical advancements, including high frequency, multiplane transducers, digital acquisition and display, and left-sided contrast agents, TEE is emerging as a promising method for evaluating coronary artery disease. Visualization of proximal coronary artery stenoses and coronary artery anomalies is already possible. Research studies using TEE measurement have contributed to understanding coronary artery physiology and may prove to be a valuable clinical tool in the future.

Coronary Disease↗
PubMed2000

Long-term outcome in congenitally corrected transposition of the great arteries: a multi-institutional study.

OBJECTIVES: The purpose of this study was to determine long-term outcome in adults with congenitally corrected transposition of the great arteries (CCTGA), with particular emphasis on systemic ventricular dysfunction and congestive heart failure (CHF). BACKGROUND: Patients with CCTGA have the anatomical right ventricle as their systemic pumping chamber, with ventricular dysfunction and CHF being relatively common in older adults. METHODS: Retrospective analysis of records of 182 patients from 19 institutions were reviewed to determine current status and possible risk factors for systemic ventricular dysfunction and CHF. Factors considered included age, gender, associated cardiac defects, operative history, heart block, arrhythmias and tricuspid (i.e., systemic atrioventricular) regurgitation (TR). RESULTS: Both CHF and systemic ventricular dysfunction were common in groups with or without associated cardiac lesions. By age 45, 67% of patients with associated lesions had CHF, and 25% of patients without associated lesions had this complication. The rates of systemic ventricular dysfunction and CHF were higher with increasing age, the presence of significant associated cardiac lesions, history of arrhythmia, pacemaker implantation, prior surgery of any type, and particularly with tricuspid valvuloplasty or replacement. Aortic regurgitation (a previously unreported problem) was also relatively common in this patient population. CONCLUSIONS: Patients with CCTGA are increasingly subject to CHF with advancing age; this complication is extremely common by the fourth and fifth decades. Tricuspid (systemic atrioventricular) valvular regurgitation is strongly associated with RV (anatomical right ventricle connected to aorta in CCTGA patients; systemic ventricle in CCTGA) dysfunction and CHF; whether it is causative or a secondary complication remains speculative.

Adult↗
PubMed1999

Best method in clinical practice and in research studies to determine left atrial size.

Although the anteroposterior dimension of the left atrium is universally used in clinical practice and research, we hypothesized that it may be an inaccurate surrogate for volume because its use is based on the unlikely assumption that there is a constant relation among atrial dimensions. The following measurements of the left atrium were made at end ventricular systole: (1) M-mode-derived anteroposterior linear dimension from the parasternal long-axis view; (2) digitized planimetry of the left atrial (LA) cavity from the apical 4-chamber view; and (3) digitized planimetry of the LA cavity from the apical 2-chamber view. The following volume calculations were obtained from these digital measurements: (1) volume derived from the M-mode dimension assuming a spherical shape; (2) volume derived from the single plane area-length of apical 4-chamber view, which assumes that LA geometry can be generalized from a single 2-dimensional plane; and (3) volume derived from the biplane method of discs. The correlation coefficient between the M-mode and biplane methods of determining LA volume was r = 0.76. The mean difference (+/-2 SDs) between these methods is -25 +/- 33 ml. The correlation coefficient between the single plane apical 4-chamber and biplane methods of determining LA volume is r = 0.97. The mean difference (+/-2 SDs) between these methods was -5.0 +/- 12 ml, indicating good agreement. The M-mode measure of the left atrium is an inaccurate representation of its size. Two-dimensional-derived LA volumes provide a more accurate measure of the true size of the left atrium and are more sensitive to changes in LA size. When an echocardiographic measure of LA size is made either in an individual patient or as a variable in a research study, the M-mode measure should be avoided.

Adolescent↗
PubMed1999

Diagnostic accuracy of pediatric echocardiograms performed in adult laboratories.

Although cardiologists who treat adults have been evaluating pediatric patients using echocardiography since the early 1980s, the diagnostic accuracy of such studies has never been tested. To prospectively assess diagnostic accuracy of pediatric echocardiograms performed in adult laboratories (adult-lab echos) compared with evaluations of the same patients in pediatric laboratories (pediatric-lab echos), we gathered data from 66 patients, ages 1 day to 18 years (median 19 months), who underwent adult-lab echos in community hospitals or private offices before evaluation by a pediatric cardiologist; subsequently, 65 underwent pediatric-lab echos in a university hospital laboratory. Echocardiographic diagnoses were compared with (1) diagnoses proved by catheterization or surgery (25 patients), and (2) echocardiographic diagnoses verified by blinded duplicate-observer review (41 patients). Eighteen patients had no cardiac disease; 42 had simple lesions, 5 had intermediate lesions, and 1 had a complex lesion. In 25 patients with 46 procedure-proven diagnoses, the most important error per adult-lab echo was major in 11 (44%), moderate in 7 (28%), and minor in 3 (12%); in pediatric-lab echos it was major in 0 (0%), moderate in 1 (4%), and minor in 1 (4%). In 41 patients with 62 duplicate-observer-verified diagnoses, the most important error per adult-lab echo was major in 5 (12%), moderate in 12 (29%), and minor in 5 (12%); pediatric-lab echos had no errors. In 35 of 66 adult-lab echos (53%), the most important error was major or moderate. Of these, 71% were interpretive, 17% technical, and 11% both. Error incidences were not related to patient age, study year, use of color Doppler, or complexity of diagnoses. In 29 of these 35 patients, pediatric-lab echos resulted in altered clinical management, including 12 surgeries and 2 averted surgeries. In 3 of the 29, delayed diagnoses were associated with fixed pulmonary vascular disease, hypoxemic spells, and vascular collapse with severe metabolic acidosis. This study reveals a high incidence of diagnostic errors in pediatric echocardiograms performed in community-based adult laboratories, despite a preponderance of patients with simple diagnoses or no heart disease.

Adolescent↗
PubMed1999

Echocardiography in patients with suspected endocarditis: a cost-effectiveness analysis.

PURPOSE: We sought to determine the appropriate use of echocardiography for patients with suspected endocarditis. PATIENTS AND METHODS: We constructed a decision tree and Markov model using published data to simulate the outcomes and costs of care for patients with suspected endocarditis. RESULTS: Transesophageal imaging was optimal for patients who had a prior probability of endocarditis that is observed commonly in clinical practice (4% to 60%). In our base-case analysis (a 45-year-old man with a prior probability of endocarditis of 20%), use of transesophageal imaging improved quality-adjusted life expectancy (QALYs) by 9 days and reduced costs by $18 per person compared with the use of transthoracic echocardiography. Sequential test strategies that reserved the use of transesophageal echocardiography for patients who had an inadequate transthoracic study provided similar QALYs compared with the use of transesophageal echocardiography alone, but cost $230 to $250 more. For patients with prior probabilities of endocarditis greater than 60%, the optimal strategy is to treat for endocarditis without reliance on echocardiography for diagnosis. Patients with a prior probability of less than 2% should receive treatment for bacteremia without imaging. Transthoracic imaging was optimal for only a narrow range of prior probabilities (2% or 3%) of endocarditis. CONCLUSION: The appropriate use of echocardiography depends on the prior probability of endocarditis. For patients whose prior probability of endocarditis is 4% to 60%, initial use of transesophageal echocardiography provides the greatest quality-adjusted survival at a cost that is within the range for commonly accepted health interventions.

Adult↗