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Biomedical subjects

J E Pope

Publications and source records attributed to J E Pope.

At least 37 records · Page 2Linked to original sources
PubMed1995

Variability of skin scores and clinical measurements in scleroderma.

OBJECTIVE: To determine the variability of several clinical outcome measurements commonly used in scleroderma clinical trials. METHODS: Ten researchers, members of a multicenter placebo controlled trial of methotrexate in early diffuse scleroderma, studied the intraobserver and interobserver variability of variables used to assess efficacy in scleroderma trials. RESULTS: For most measures, the variability within an observer was less than that found between observers, and therefore the intraobserver reliability was better than the interobserver reliability. The reliability of the modified Rodnan skin score exceeded the Rodnan skin score. Measures with inherent interpretation such as global assessments and skin scores had more variability than easily performed measurements such as grip strength and oral opening. CONCLUSION: Some of our variability was higher than variability previously reported; this could be due to the large number of examiners and patients in our study.

Female↗
PubMed1995

The dental health of single male hostel dwellers in Leeds.

Attitudes and behaviour towards oral health among 104 homeless men in Leeds were assessed at interview. Of these, 101 agreed to a subsequent dental examination. The findings confirmed a high level of normative need despite a low level of felt need. Appointments were offered at two local community dental clinics, but the majority of men failed to attend. Appropriate provision of dental care is discussed and recommendations made for future developments.

Adolescent↗
PubMed1995

Sample size calculations in scleroderma: a rational approach to choosing outcome measurements in scleroderma trials.

Subjects with both diffuse and limited scleroderma were studied to calculate the baseline characteristics of several commonly used outcome measurements in order to provide parameters for sample size calculations for scleroderma clinical trials. From these estimates, outcome measurements were chosen as potentially responsive to change in clinical trials if their sample sizes were not prohibitively large. Forty-five patients with scleroderma were systematically assessed to determine the means and standard deviations whereby sample size calculations can be performed using this information. Examples of sample sizes were determined for the entire group, and for 2 subsets: those with diffuse scleroderma and those with diffuse disease of recent onset. Many baseline characteristics were significantly different in patients with diffuse compared to limited systemic sclerosis. The baseline values were different for the Health Assessment Questionnaire (HAQ) disability score, Functional Index, grip strength, oral aperture, finger-to-palm distance, skin score, and physician global assessment. Sample sizes can vary widely depending upon the outcome measurement chosen and the range of deltas used within the different scleroderma subsets. Sample size requirements for many outcome measures are extremely large due to marked variability in the baseline measures. Primary outcome measures in scleroderma trials should be chosen which have adequate power to detect a minimal clinically relevant change in the primary outcome measurements at the sample sizes employed. All other outcome measures should be ranked as secondary. Skin scores, global assessments, and grip strength measurements require smaller sample sizes than the other outcome measurements which were studied. Sample sizes in future trials will vary depending upon the proportion of patients with diffuse and limited scleroderma who are included.

Female↗
PubMed1994

Simultaneous ST-segment measurements using standard and monitoring-compatible torso limb lead placements at rest and during coronary occlusion.

Electrocardiographic recordings used to assess ST-segment deviation are performed using both standard and torso limb lead positions, where bony prominences give more artifact-free signal. Whereas significant QRS artifact can be introduced by such changes in lead location, the impact on ST-segment measurements has never been assessed. Digital electrocardiographic recordings were performed in 29 patients throughout elective angioplasty balloon inflation in the left anterior descending (n = 12), right coronary (n = 14), and circumflex (n = 3) arteries. In all cases, unipolar leads V1, V4, and V6 were affixed to the torso lead positions, allowing reconstruction of simultaneously acquired standard and modified 9-lead electrocardiograms (ECGs). ST levels in the 26 patients who had ST deviation during angioplasty were compared at both baseline and peak ischemia of up to 1,046 microV in the anterior, and 551 microV in the inferior leads. Differences in recorded ST levels for modified versus standard lead locations were all < 100 microV, even at peak ischemia. Although ST-segment elevation in the inferior leads appeared to show slightly more pronounced differences between lead sets than did anterior elevation, all differences were < 100 microV. Thus, measurement of ST-segment levels appears unlikely to be importantly affected by the intermixture of ECGs recorded with standard lead positions and ECGs recorded with monitoring-compatible lead positions on the torso. Recalibration of ST-segment measurements may be necessary for meticulous quantification of ischemia, infarct size, or other measurements that might be affected by variations < 100 microV.

Constriction↗
PubMed1994

Comparison of continuous ST-segment recovery analysis with methods using static electrocardiograms for noninvasive patency assessment during acute myocardial infarction. Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) 7 Study Group.

Continuous ST-segment recovery analysis and 5 static methods using ST-segment comparison between a pre- and post-treatment electrocardiogram were compared for their ability to predict infarct-related artery patency in 82 patients with acute myocardial infarction who underwent angiography a median of 124 minutes after onset of thrombolytic treatment. Accuracy at the moment of angiography was 85% (95% confidence interval [CI] 77% to 93%) for the continuous method, and 68% (CI 57% to 78%), 78% (CI 69% to 87%), 83% (CI 74% to 91%), 82% (CI 73% to 90%), and 80% (CI 71% to 89%) for the static methods. At the moment of angiography the most accurate static method and the continuous method agreed in patency assessment in 90% of the patients (CI 84% to 97%). Agreement was reduced to 83% (CI 75% to 91%) of patients when a patency assessment was performed earlier at 90 minutes after treatment onset, and was only 77% (CI 68% to 86%), at 60 minutes. Early disagreement was mainly seen when the continuous ST recording showed ST recovery from a delayed peak ST elevation after the pretreatment static electrocardiogram or when dynamic ST changes suggesting cyclic reperfusion occurred. Continuous ST-segment recovery analysis appears to be as accurate as the most accurate static methods. Continuously updated reference points appear to give important additional information when ST recovery follows a delayed peak ST elevation or when re-elevation occurs, suggesting cyclic flow changes. Such findings appear to affect about half of patients with acute myocardial infarction treated with intravenous thrombolysis, particularly early after administration of therapy.

Aged↗
PubMed1994

Platelet calcium transport in hypertension.

To determine platelet Ca2+ transport entities involved in increased cytosolic Ca2+ in the platelets of hypertensive individuals, we studied the relations between blood pressure and Ca2+ transporters in platelet membranes from 22 white male volunteers 32 to 68 years old. We used thapsigargin, a specific inhibitor of the internal membrane Ca(2+)-ATPase, to differentiate between plasma membrane and internal membrane Ca(2+)-ATPases. Inositol 1,4,5-trisphosphate-mediated and Ca2+ ionophore (A23187)-induced Ca2+ release was also assayed in membrane preparations using rhod-2, a fluorescent Ca2+ indicator. Levels of glycoprotein IIIa, a possible component of agonist-mediated Ca2+ influx, were measured by immunoblotting. The results show that plasma membrane Ca(2+)-ATPase is decreased as a function of diastolic blood pressure (P < .002), whereas the internal membrane Ca(2+)-ATPase is not (P < .148). Neither activity is correlated with age or systolic blood pressure. However, inositol trisphosphate-mediated Ca2+ release is negatively correlated with age (P < .024) but not blood pressure. Glycoprotein IIIa levels and A23187-induced Ca2+ release were not related to age or blood pressure, demonstrating that inhibition of the plasma membrane Ca(2+)-ATPase was not a result of differences in the proportion of plasma membrane in the preparation or differences in intravesicular Ca2+ concentration. Inhibition of the plasma membrane Ca(2+)-ATPase could directly cause elevation of cytoplasmic Ca2+ and enhancement of platelet sensitivity.

Adult↗
PubMed1994

The impact of autoperfusion on quantitative electrocardiographic parameters of ischemia severity, extent, and "burden" during salvage of elective coronary angioplasty.

Long angioplasty inflations have been reported using an autoperfusion system that delivers oxygenated blood distal to the balloon segment. The safety and efficacy of this system has been demonstrated in anatomically selected patients. The clinical use, however, is frequently to stabilize intimal dissection in unselected patients. We reviewed 12-lead continuous electrocardiographic (ECG) recordings in 40 patients in whom prolonged salvage with autoperfusion was attempted. Sub-optimal results were stabilized in 36 of 40, while 4 patients had urgent bypass. The presence of ischemia, as > or = 100 uV ST elevation over the 12 lead ECG, and the total ST deviation over all leads over the entire inflation period (total ischemic "burden") were compared within each patient between the longest standard balloon and autoperfusion inflations. Median duration of inflation was 3.03 min. with balloon vs. 15.6 min. with autoperfusion (p < 0.00002). Of the 40 patients, 35 (87%) had ECG ischemia with balloon vs. 18 (45%) with autoperfusion (p < .00002). Median severity of peak ST deviation was 321 uV with balloon vs. 132 uV with autoperfusion (p = 0.0001). Median extent of ST elevation was 3 leads with balloon vs. 0 leads with autoperfusion (p = 0.0001). Median total ischemic burden was similar with balloon (1173 uVmin) and autoperfusion (1083 uVmin, NS) despite the fivefold longer inflation duration with autoperfusion. Thus, in patients selected by clinical necessity rather than optimal anatomy, severity and extent of ST elevation were significantly reduced, although not entirely eliminated, by autoperfusion.

Angioplasty, Balloon, Coronary↗
PubMed1993

A meta-analysis of the effects of nonsteroidal anti-inflammatory drugs on blood pressure.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) have well-known gastrointestinal and renal toxic reactions. Effects of NSAIDs on blood pressure are less appreciated. A meta-analysis was performed to determine the hypertensive effects of NSAIDs and rank them by magnitude of change in mean arterial pressure (MAP). METHODS: A literature search of published English-language studies of NSAIDs and their effects on blood pressure was done. Studies were included if they met the following criteria: (1) the studies were intervention studies; (2) NSAIDs at any dose or aspirin at doses of 1.5 g/d or greater were included; (3) documentation of blood pressure was provided; and (4) the studies were 24 hours in duration. Studies were excluded if 20% or more of their participants dropped out or if the dose of antihypertensive drugs was adjusted while the subjects were taking NSAIDs. The major outcome was change in MAP while patients were receiving NSAIDs. Each NSAID arm was extracted from its trial. Information on possible confounders, including subject age, trial quality, amount of dietary salt intake, and whether study subjects were hypertensive or normotensive, was recorded. We calculated the average change in MAP on each NSAID, adjusting for confounders. RESULTS: Fifty-four studies with 123 NSAID treatment arms met inclusion criteria. The mean age of subjects was 46 years. Of the 1324 participants, 1213 subjects (92%) were hypertensive. The effects of NSAIDs on blood pressure were found solely in hypertensive subjects. Among these, the increase in MAP after adjusting for amount of dietary salt intake was 3.59 mm Hg for indomethacin (57 treatment arms), 374 mm Hg for naproxen (four arms), and 0.49 mm Hg for piroxicam (four arms). The MAP decreased by 2.59 mm Hg for placebo (10 arms), 0.83 mm Hg for ibuprofen (six arms), 1.76 mm Hg for aspirin (four arms), and 0.16 mm Hg for sulindac (23 arms). The effects on MAP by using placebo, sulindac, and aspirin were statistically significantly different from indomethacin. CONCLUSIONS: In short-term use, NSAIDs vary considerably in their effect on blood pressure. Of the drugs studied, indomethacin and naproxen were associated with the largest increases in blood pressure. The average effects of piroxicam, aspirin, ibuprofen, and sulindac were negligible.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1993

Continuously updated 12-lead ST-segment recovery analysis for myocardial infarct artery patency assessment and its correlation with multiple simultaneous early angiographic observations.

Early angiography may not adequately subgroup patients with myocardial infarction if cyclic changes in coronary flow occur frequently. From a pilot experience using a new 12-lead ST-segment monitor, a continuously updated, self-referenced ST-recovery analysis method was developed to quantify both instantaneous recovery, as a noninvasive marker of patency, and cumulative ST recovery over time, as a marker of the speed, stability and duration of reperfusion. In 22 patients with acute infarction in whom 44 observations of unique angiographic patency were noted within 6 hours of presentation, serial patency assessments simultaneous with all angiographic observations predicted coronary occlusion with 90% sensitivity and 92% specificity. Of the 22 patients, 11 (50%) had multiple ST trend transitions suggesting cyclic changes in coronary flow before catheterization. Speed, stability and duration of ST-segment recovery were defined by the time to first 50% ST recovery, total number of ST-trend transitions and patent physiology index (percentage of monitoring period showing ST recovery), respectively. Subgrouped angiographically, the median (interquartile range) for cumulative ST parameters with patent (n = 8) versus occluded (n = 14) arteries were, respectively--time to 50% recovery, 1.57 (1.16, 1.70) versus 0.17 (-0.47, 0.32) hours; number of reelevation/recovery events, 1.5 (1, 3) versus 3 (1, 3); and patent physiology index, 52 (47, 59) versus 50 (5, 73). Thus, continuous ST-segment recovery analysis appears to predict simultaneous angiographic patency over serial assessments, whereas cumulative parameters appear to contain independent information, probably because of patency changes before or after angiography.

Cardiac Catheterization↗
PubMed1993

Outcome measurement in scleroderma clinical trials.

Clinical trials in scleroderma were reviewed to assess the clinimetric properties of frequently used outcome measures. Twenty-seven controlled intervention studies were found in the English literature; nine demonstrated effective therapy. The outcome measures used included skin involvement, functional status, physical performance (grip strength, oral aperture), and internal organ involvement (pulmonary, gastrointestinal, renal, and cardiac). Very few outcome measures detected between- or within-group differences even when an active drug was compared with a placebo. Skin measures were found to yield statistical differences in seven studies, patient global assessment in three, and physician global assessments in four. Internal organ measures detected differences between groups only rarely; the pulmonary diffusing capacity was statistically different twice. Physical performance measures (eg, grip strength and oral aperture) never yielded statistical differences, and in only one of five trials did a functional assessment detect statistical differences. To show drug efficacy in future trials in scleroderma, better outcome measures need to be developed and a consensus obtained on which outcomes to use so that potentially effective therapies can be tested in a standardized fashion against a placebo or current therapy. Currently, because of a lack of clinimetric data on outcome measures, therapeutic inefficacy cannot be differentiated from a lack of sensitivity in the outcome measures used. In the future, outcome measures should be chosen on the basis of the adequacy of their reliability, construct, and content validity and be sensitive to change. Ideally, outcome measures also should have criterion validity, ie, show a strong association between the measure (such as a skin score) and an irrefutable gold standard (such as skin pathology).

Clinical Trials as Topic↗
PubMed1993

Continuous 12-lead ST-segment recovery analysis in the TAMI 7 study. Performance of a noninvasive method for real-time detection of failed myocardial reperfusion.

BACKGROUND: If a practical, reliable, noninvasive marker of failed reperfusion was available in real time, the benefits of further therapy in this patient subgroup could be tested. We developed a method of 12-lead ST-segment recovery analysis using continuously updated reference points to provide such a marker. METHODS AND RESULTS: In this study, our method was prospectively tested in 144 patients given thrombolytic therapy early in myocardial infarction. All patients had 12-lead continuous ST-segment monitoring and acute angiography, each analyzed in an independent, blinded core laboratory. ST-segment recovery and re-elevation were analyzed up to the moment of angiography, at which time patency was predicted. Predictions were correlated to angiographic infarct artery flow, with TIMI flow 0 to 1 as occluded and TIMI flow 2 to 3 as patent. Infarct artery occlusion was seen on first injection in 27% of patients. The positive predictive value of incomplete ST recovery or ST re-elevation by our method was 71%, negative predictive value 87%, with 90% specificity and 64% sensitivity for coronary occlusion. ST recovery analysis predicted patency in 94% of patients with TIMI 3 flow versus 81% of patients with TIMI 2 flow and predicted occlusion in 57% of patients with collateralized occlusion versus 72% of patients with non-collateralized occlusion. In a regression model including other noninvasive clinical descriptors, ST recovery alone contained the vast majority of predictive information about patency. CONCLUSIONS: In a blinded, prospective, angiographically correlated study design, 12-lead continuous ST-segment recovery analysis shows promise as a practical noninvasive marker of failed reperfusion that may contribute substantially to currently available bedside assessment. Our data also suggest that patients with TIMI 2 flow or with collateralized occlusions may represent a physiological spectrum definable with ST-segment recovery analysis.

Adolescent↗
PubMed1993

ST-segment recovery as an endpoint in acute myocardial infarction trials. Past, present, and future.

Traditional, comparative acute myocardial infarction trials have used morbidity and mortality as endpoints, requiring large study populations. Left ventricular function and angiographic infarct-related artery patency have, therefore, been used as alternative endpoints. These assessments are costly, risk-laden, and put a large demand on resources not available in every hospital. This has led to an increased interest in noninvasive endpoints for comparative trials. This study describes the history and possibilities of ST-segment recovery analysis as an endpoint in acute myocardial infarction trials.

Electrocardiography↗
PubMed1992

Evolution of an automated ST-segment analysis program for dynamic real-time, noninvasive detection of coronary occlusion and reperfusion.

Patients in whom early and stable reperfusion through the infarct artery fails after thrombolytic treatment might benefit from further revascularization therapy. A reliable noninvasive technique able to detect both reperfusion and reocclusion would be useful to test this hypothesis. However, no such technique presently exists. ST-segment recovery analysis using continuous digital 12-lead ST monitoring has been shown to be an accurate predictor of infarct artery patency in real time. This method was dependent on a trained clinician's analysis of the recordings on a personal computer. For optimal bedside application, salient principles of this ST-segment recovery analysis were converted into algorithms and built into the ST monitor software. The essentials of these algorithms are described in this report.

Electrocardiography↗
PubMed1992

Performance of the automated complete Selvester QRS scoring system in normal subjects and patients with single and multiple myocardial infarctions.

The automated version of the complete Selvester QRS scoring system for estimation of myocardial infarct size was evaluated in 1,344 normal subjects, 706 patients with a single myocardial infarction (366 with inferior infarction, 277 with anterior infarction and 63 with posterolateral infarction) and 131 patients with combined inferior and anterior infarction. The presence and location were determined by angiographic and ventriculographic criteria. The performance of the overall 32-point system, each of the 19 criteria and the 13 criteria sets and each of the 35 criteria within the 13 sets was examined. The mean point scores were 1.7 for normal subjects, 3.7 for posterolateral infarction, 4.1 for inferior infarction, 6.3 for anterior infarction and 6.9 for multiple infarcts. A score greater than 4 yielded a sensitivity of 67% for anterior infarction, 41% for inferior infarction, 32% for posterolateral infarction and 72% for multiple infarcts. However, 7 of 32 criteria failed to achieve 95% specificity and 10 of 35 criteria in criteria sets had a sensitivity that was even lower than their false positive rate. The automated Selvester QRS scoring system currently has limitations that are attributable to development of the original system, which used manual scoring techniques and established criteria limits from middle-aged men. Future automated analysis should use gender- and age-dependent criteria limits.

Computer Simulation↗
PubMed1991

Specificity and sensitivity of QRS criteria for diagnosis of single and multiple myocardial infarcts.

A subset of 3 criteria from the complete Selvester scoring system has been proposed earlier for electrocardiographic screening of healed myocardial infarcts. This subset yielded 95% specificity and high sensitivity for single anterior and inferior infarcts. In the present study, an automated version of these criteria was applied to 1,344 electrocardiograms from normal subjects (473 normal subjects as determined by cardiac catheterization and 871 apparently normal subjects by history and physical examination), to 706 from subjects with single myocardial infarction, and to 131 from subjects with combined anterior and inferior myocardial infarcts. Of the single infarcts, 366 had inferior, 277 anterior and 63 posterolateral locations. Presence and location of infarcts were judged from left ventriculograms and coronary angiograms. Overall specificity was only 86%, whereas overall sensitivity for the infarct population was 77%. Specificity was lower in men than in women; it was also lower in older than in younger subjects. One of the screening criteria (R greater than or equal to 40 ms in V1) may possibly be eliminated to augment specificity; this can be done with only minor loss of sensitivity. Differences in wave form measurements between the manual and computer methods account for a large part of the deterioration of specificity in this study compared with previously published results. Computer application of the screening criteria requires altered criteria limits in comparison with those used in manual application. Probably sex- and age-dependent criteria limits should be used.

Age Factors↗