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Biomedical subjects

C Wolfe

Publications and source records attributed to C Wolfe.

At least 19 recordsLinked to original sources
PubMed1995

The SF-36 health survey questionnaire: is it suitable for use with older adults?

An Anglicized version of the SF-36, a recently developed generic health status measure, was tested among people aged 65 years and over in hospital outpatient and general practice settings as both a self-completed and interview-administered instrument. The SF-36 was quick to complete, with 84% completed in 10 minutes or less (median time 8 minutes), while the distribution of scores provided further evidence of its sensitivity and validity. As an interview-administered instrument the SF-36 was acceptable among all age groups, although 32% of outpatients and 10% of general-practice patients, consisting predominantly of people aged 75 years and over with poor physical or mental health scores, felt unable to self-complete the questionnaire. In addition, 26% of respondents missed out at least one of the 36 statements, with missing items being significantly related to older age and self-completion. Missing responses were mainly concentrated on a small number of questions whose emphasis on work or vigorous activities meant that they were frequently regarded as not applicable by elderly people. Suggested modifications to these questions for elderly respondents are given. With these changes the SF-36 is regarded as suitable for use as a self-completed questionnaire among the younger age group of elderly people, although some assistance may often be required by people aged 75 years and over and especially those with poor physical or mental health.

Activities of Daily Living↗
PubMed1995

Stroke care in Europe. Can we learn lessons from the different ways stroke is managed in different countries?

Stroke is a major health care problem in the European Union and consumes significant resources. The mortality rates from stroke and treatment strategies vary significantly between member states. Only by comparison between centres in different member states with differing health care delivery can the effect of these varying approaches to the management of stroke on outcome be assessed. Conducting a study on a European wide basis in centres which are known to differ in terms of treatment strategies and outcomes allows an immediate analysis of the effectiveness, resource requirements and cost of different methods of managing stroke patients. This paper addresses the current burden of stroke and strategies for its management. An outline of a European Union project, assessing how stroke is managed in different countries, is provided with the aim of indicating a strategy for discovering and promoting more cost-effective services for stroke care in the future.

Aged↗
PubMed1992

First steps in the development of an information and counselling service for women with an abnormal smear result.

A study was conducted to develop and evaluate an information leaflet and to investigate the acceptability of a counselling service for women with an abnormal smear result. A newly constructed information leaflet which addressed concerns related to receipt of an abnormal smear result and its medical management was compared for ease of readability with five other leaflets in current use and found to be superior. 144 women were given the leaflet either prior to a colposcopy examination or outpatient ablative treatment and randomly assigned to two recruitment strategies to examine the acceptability of a counselling interview. There was no significant difference between the two strategies and an uptake rate of 80% suggested that women welcomed such an opportunity. An interview evaluation schedule yielded a 98% positive response rate which indicated that the women were satisfied with the counsellor and found the interview useful. Significant differences emerged before and after medical intervention. Patients reported less anxiety, improved mood, and less distress related to the smear result and subsequent medical procedures immediately after the medical interventions (P less than 0.001).

Anxiety↗
PubMed1991

Desmethylimipramine promotes recovery of self-stimulation from the prefrontal cortex following footshock.

Intracranial self-stimulation (ICSS) was assessed from the prefrontal cortex in CD-1 mice immediately (0 h), 24 h and 168 h following exposure to uncontrollable footshock. Marked reductions in ICSS rates were observed in all mice immediately following the stressor. Although the ICSS alterations were transient in some animals, ICSS rates were reduced in the majority of animals 24-h and 168-h poststressor. Mice of either the shock or no shock treatment groups were administered either saline or desmethylimipramine (DMI, 5 mg/kg x 2) for 20 consecutive days. Chronic DMI ameliorated the stressor-induced ICSS deficits from the prefrontal cortex. Potential explanations for the stressor-provoked variations in ICSS and the effects of DMI are discussed.

Animals↗
PubMed1990

Effects of nicardipine, a calcium antagonist, on myocardial salvage and high energy phosphate stores in reperfused myocardial injury.

The current study determined the effectiveness of nicardipine, a 1,4-dihydropyridine calcium antagonist, in preserving reperfused myocardium in a cat model of temporary coronary occlusion and ascertained if replenishment of myocardial phosphate stores during reperfusion as defined by phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy was indicative of salvage. Twenty open chest, anesthetized cats were studied with use of a snare ligature around the proximal left anterior descending coronary artery, with a coil sutured to the epicardial surface overlying the distribution of the artery. Peak areas of phosphocreatine, inorganic phosphate and adenosine triphosphate (ATP) NMR signals were measured during 1 h of occlusion followed by 1.5 h of reperfusion. Infarct size and jeopardy area were determined in vitro by simultaneous infusion of phthalocyanine blue dye and triphenyltetrazolium chloride into the aorta and the left anterior descending coronary artery, respectively, after 5 h of myocardial reperfusion. Nicardipine-treated and control groups had similar jeopardy area values (41.2 +/- 1.6% versus 47.4 +/- 3.1% of the left ventricle), but infarct area was significantly reduced in the nicardipine-treated group (3.2 +/- 1.1% versus 24.9 +/- 7.5% of jeopardy area, p less than 0.01). High energy phosphate compounds remained markedly altered during reperfusion in both groups. No significant improvement in phosphocreatine or inorganic phosphate recovery was observed in animals pretreated with nicardipine despite an 87% reduction in infarct size. Myocardial ATP was greater during reperfusion in the nicardipine-treated compared with the control group (average over initial 90 min of reperfusion 58 +/- 6% versus 46 +/- 3% of baseline values, p less than 0.05), suggesting improved recovery of ATP. However, the measured levels of high energy phosphate compounds during reperfusion and their ratios did not correlate with infarct size and thus were not predictive of myocardial salvage.

Adenosine Triphosphate↗
PubMed1990

Interstudy reproducibility of dimensional and functional measurements between cine magnetic resonance studies in the morphologically abnormal left ventricle.

The validity of geometric formulas to derive mass and volumes in the morphologically abnormal left ventricle is problematic. Imaging techniques that are tomographic and therefore inherently three-dimensional should be more reliable and reproducible between studies in such ventricles. Determination of reproducibility between studies is essential to define the limits of an imaging technique for evaluating the response to therapy. Sequential cine magnetic resonance (MR) studies were performed on patients with dilated cardiomyopathy (n = 11) and left ventricular hypertrophy (n = 8) within a short interval in order to assess interstudy reproducibility. Left ventricular mass, volumes, ejection fraction, and end-systolic wall stress were determined by two independent observers. Between studies, left ventricular mass was highly reproducible for hypertrophied and dilated ventricles, with percent variability less than 6%. Ejection fraction and end-diastolic volume showed close reproducibility between studies, with percent variability less than 5% End-systolic volume varied by 4.3% and 4.5% in dilated cardiomyopathy and 8.4% and 7.2% in left ventricular hypertrophy for the two observers. End-systolic wall stress, which is derived from multiple measurements, varied the greatest, with percent variability of 17.2% and 15.7% in dilated cardiomyopathy and 14.8% and 13% in left ventricular hypertrophy, respectively. The results of this study demonstrate that mass, volume, and functional measurements are reproducible in morphologically abnormal ventricles.

Adult↗
PubMed1990

Depression and recovery of right ventricular function after cardiopulmonary bypass.

Transient left ventricular dysfunction is commonly described in association with cardiopulmonary bypass (CPB). We evaluated changes in right ventricular (RV) function after elective cardiac surgery in 24 patients with normal preoperative cardiac function. In all, irrespective of distribution of coronary artery disease or use of pharmacologic support, a transient depression of RV systolic function with respect to both preinduction and initial postoperative (Postop) values occurred 262 +/- 116 min post-CPB as represented by a decrease in RV stroke volume index (25.0 +/- 1.7 vs. 33.4 +/- 1.9 ml/m2 Postop) and RV ejection fraction (31.0 +/- 2.2 vs. 45.6 +/- 2.5% Postop), and an increase in RV end-systolic and end-diastolic volume indices. This depression responded readily to pharmacologic therapy within 2 h, resolved within 24 h, and had no adverse consequences in these otherwise healthy patients. Further studies are needed to identify the cause of this phenomenon and its importance in patients with preexisting cardiac dysfunction.

Aged↗
PubMed1990

[Three-dimensional analysis of the regional contractility of the normal and the cardiomyopathic left ventricle using cine-magnetic resonance imaging].

The left ventricular regional contractile pattern, global function and mass of normal subjects and patients with idiopathic dilated cardiomyopathy was compared using cine magnetic resonance imaging (MRI) in a short-axis imaging plane. Left ventricular ejection fraction and mass were 64.3 +/- 2.5% and 115 +/- 10 g in normal hearts and 23.5 +/- 3.1% and 194 +/- 20 g in dilated cardiomyopathic hearts (p less than 0.001 and p less than 0.002). Left ventricular end-diastolic wall thickness was homogeneous in normal hearts except for the posterior wall at the basal level, which was significantly thinner compared to the anterolateral wall and the septum (p less than 0.02). End-diastolic wall thickness in the cardiomyopathic group was significantly more heterogeneous and was thinner at the apical compared to the basal level (p less than 0.02) as well as in the segment of the posterior compared to the anterolateral and septal wall (p less than 0.005 and p less than 0.03). In normal hearts, left ventricular end-systolic wall thickness was progressively greater from base to apex for the anterolateral (p less than 0.01) and posterior wall (p less than 0.02) and the septum (p less than 0.02). Such a uniform gradient of end-systolic wall thickness was not present in hearts with dilated cardiomyopathy. It was even reversed for the anterolateral wall with decreasing thickness from base to apex (p less than 0.03). Left ventricular mean systolic wall thickening increased progressively from base to apex (p less than 0.005) in normal hearts, whereas there was no significant gradient from base to apex in hearts with dilated cardiomyopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Noninvasive evaluation of global left ventricular function with use of cine nuclear magnetic resonance.

Previous reports have validated the accuracy of nuclear magnetic resonance (NMR) imaging for quantitating ventricular volumes and myocardial mass. In this study, a new rapid NMR imaging method, cine NMR imaging, was used to compare left ventricular volumes determined from the transverse plane and short-axis plane in healthy volunteers and patients with dilated cardiomyopathy. With use of the short-axis plane, left ventricular mass at end-systole and end-diastole were determined and left ventricular systolic wall thickening at three different levels was assessed. For validation in the current study, cine NMR imaging and two-dimensional echocardiographic measurements of left ventricular volumes were correlated. Left ventricular volumes of the normal volunteers (end-systolic volume = 34 +/- 3.8 ml, end-diastolic volume = 90.4 +/- 7.2 ml) and patients with cardiomyopathy (end-systolic volume = 173 +/- 28.3 ml, end-diastolic volume = 219.5 +/- 29.6 ml) obtained in the transverse plane were nearly identical to those obtained in the short-axis plane (normal volunteers, end-systolic volume = 30.3 +/- 3.5 ml, end-diastolic volume = 84.7 +/- 7.0 ml and patients with cardiomyopathy, end-systolic volume = 179.1 +/- 27.8 ml, end-diastolic volume = 227 +/- 30.9 ml) and correlated highly (r = 0.91) with volumes obtained by two-dimensional echocardiography. Assessment of left ventricular mass over a broad range using cine NMR imaging in a short-axis plane was identical at end-systole (normal volunteers, 117 +/- 10 g; patients with cardiomyopathy, 202 +/- 20 g) and end-diastole (normal volunteers, 115 +/- 10 g; patients with cardiomyopathy, 194 +/- 21 g).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Cyclosporine versus azathioprine: a review of 200 consecutive cadaver renal transplant recipients.

Most renal transplant centers report an increase in graft survival when cyclosporine is used as a primary immunosuppressant. We report the outcome of 200 consecutive cadaver renal transplant recipients among whom initial immunosuppression and risk factors were similar except for the substitution of cyclosporine for azathioprine in the second 100 recipients. Azathioprine-treated recipients had significantly increased (p less than 0.05) mean hospital stays (31.9 versus 18.3 days), incidence of first rejection episodes (85 versus 31) and methylprednisolone dose (3.38 versus 0.06 gm. per patient). Cyclosporine-treated recipients had a significantly higher 1-year mean serum creatinine level (1.85 versus 1.56 mg. per dl.) and 1-year actual graft survival (83 versus 58 per cent). Despite mild nephrotoxicity, cyclosporine is superior to azathioprine as a primary immunosuppressant in cadaver kidney transplantation.

Azathioprine↗
PubMed1989

Demarcation of myocardial ischemia: magnetic susceptibility effect of contrast medium in MR imaging.

Dysprosium diethylenetriamine-pentaacetic acid-bis (methylamide) (DTPA-BMA), a new nonionic contrast medium for magnetic resonance (MR) imaging, produces signal loss on T2-weighted images because of induced magnetic field gradients. The potential of this agent to delineate myocardial ischemia was investigated in 10 rats with acute (30 minutes) occlusion of the left coronary artery. T2-weighted MR images were acquired before and for 1 hour after intravenous administration of 1 mmol/kg of Dy-DTPA-BMA. Before administration of the contrast medium, signal intensity (SI) in the ischemic region was significantly greater than that in the normal myocardium; however, the borders of the ischemic region were not consistently distinct. The contrast medium caused marked decrease in SI of normal myocardium (18% +/- 3% of the control value), only slight decrease in the jeopardized region (76% +/- 6% of the control value), and no discernible effects on heart rate or blood pressure. Substantial contrast between normal and ischemic myocardium persisted for 1 hour. Moderate signal loss was observed in skeletal muscle. Dy-DTPA-BMA has the potential to demarcate the myocardial area in jeopardy as a region of high signal intensity because it erases signal preferentially in the normal myocardium.

Animals↗
PubMed1987

Ventricular septal defect: visualization of shunt flow and determination of shunt size by cine MR imaging.

Cine MR imaging is a new, fast technique that employs low flip angles, short repetition and echo times, and gradient-refocused echoes. This technique was used in three patients with documented ventricular septal defects (VSDs) to obtain transverse and oblique sections of the heart spanning the cardiac cycle. In all patients, cine MR imaging showed high-velocity turbulent blood flow across the defect as areas of low signal intensity extending from the left ventricle to the right ventricle. In the oblique sections oriented parallel to the interventricular septum it was possible to identify the cross-sectional area of the VSD. Quantification of the left-to-right shunt was performed by comparing left and right ventricular stroke volumes determined from end-diastolic and end-systolic volumes of both ventricles. Cine MR imaging provides important functional information and anatomic detail in patients with VSD and may be useful for diagnosis, determination of severity, and noninvasive monitoring of the disease.

Coronary Circulation↗
PubMed1986

NADPH binding induced proton ionization as a cause of nonlinear heat capacity changes in glutamate dehydrogenase.

Functional group interactions involved in the formation of the glutamate dehydrogenase-NADPH binary complex have been studied by three independent but complementary approaches: the pH dependence of the overall dissociation constant measured by an improved differential spectroscopic technique; the pH dependence of the enthalpy of complex formation measured by flow calorimetry; and the pH dependence of the number of protons released to, or taken up from, the solvent in the complex formation reaction, measured by titration. We conclude that the coenzyme binds to the enzyme through three distinguishable interactions: a pH-independent process involving the binding of the reduced nicotinamide ring; a relatively weak "proton-stabilizing" process, occurring at low pH involving the shift at a pK of 6.3 in the free enzyme to 7.0 in the enzyme-NADPH complex; and a stronger "proton-destabilizing" process, occurring at a higher pH involving a shift of a pK of 8.5 in the enzyme down to 6.9 in the enzyme-NADPH complex. The proton ionization of the free enzyme involved in this third interaction exhibits some unusual thermodynamic parameters, having delta Go = +11.5 +/- 0.1 kcal mol-1, delta Ho = +19 +/- 1 kcal mol-1, and delta So = +23 eu. We show here that this proton ionization step is directly related to and indeed constitutes the "implicit" shift in enzyme macrostates which we have shown to be responsible for the existence of large highly nonlinear delta Cpo effects in the formation of this complex [Fisher, H. F., Colen, A. H., & Medary, R. T. (1981) Nature (London) 292, 271-272].

Animals↗
PubMed1985

Early positive technetium-99m stannous pyrophosphate images as a marker of reperfusion after thrombolytic therapy for acute myocardial infarction.

Fourteen patients with transmural acute myocardial infarction (AMI) were treated with intravenous streptokinase a mean of 4 +/- 1 hours after chest pain and underwent technetium-99m stannous pyrophosphate (Tc-99m-PPi) imaging 7 +/- 2 hours after the onset of chest pain. The early Tc-99m-PPi images were obtained to test the hypothesis that an early, strongly abnormal Tc-99m-PPi image suggests reperfusion. Eleven of 14 patients had early peaking (within 16 hours) serum creatine kinase isoenzyme levels (CK-B) at a mean of 11 +/- 3 hours. Ten of 14 patients had 3+ or 4+ acute Tc-99m-PPi images. Eight of 11 patients had patent infarct-related vessels at cardiac catheterization 15 days after AMI. One patient who had both an early positive Tc-99m-PPi image and CK-B peak level had an occluded infarct-related artery at catheterization. Acute left ventricular (LV) ejection fraction (EF) by radionuclide ventriculography was compared with LVEF on day 15, and improved from 0.37 +/- 0.13 to 0.50 +/- 0.16 (p = 0.004) in the 10 patients with strongly positive acute Tc-99m-PPi images. LVEF also improved from 0.37 +/- 0.12 to 0.49 +/- 0.15 (p = 0.003) in the 11 patients with early peaking serum CK-B values. Three patients without evidence of reperfusion failed to improve the LVEF from the initial value to the one obtained at hospital discharge. Six control patients had acute Tc-99m-PPi images 10 +/- 2 hours after chest pain; none had strongly positive acute Tc-99m-PPi images, and the mean time to peak CK-B was 19 +/- 5 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1982

Continuous noninvasive monitoring of left ventricular function during exercise by thoracic impedance cardiography-automated derivation of systolic time intervals.

Systolic time intervals (STI) obtained during exercise are useful as a method of estimating global left ventricular function. The conventional method, however, which requires a carotid pulse tracing as well as a phonocardiogram of high quality, is technically difficult under conditions of exercise. We have validated a new method of obtaining STI which employs the first derivative of thoracic electrical impedance (DZ/DT). The DZ/DT was recorded using surface electrodes and a microcomputer for automated signal processing. The new method was studied in 20 male normal subjects (aged 18 to 53 years) at rest and during increasing levels of upright exercise. Heart rate ranged from 61 to 173 beats/min. Results obtained simultaneously by both techniques showed no significant difference. Thus impedance cardiography allows continuous monitoring of STI during exercise and may prove to be a valuable addition to multistage stress testing.

Adolescent↗