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Biomedical subjects

J E Hansen

Publications and source records attributed to J E Hansen.

At least 145 records · Page 8Linked to original sources
PubMed1988

Effects of pulmonary emphysema on QRS infarct size score.

Pulmonary emphysema can produce false-positive electrocardiographic (ECG) changes of anterior myocardial infarction (MI). This problem was not addressed in earlier studies of the Selvester 54 Criteria/32 Point QRS score for MI size. The purpose of this study was to examine an automated Hewlett Packard ECG Computer Language (HP-ECL) implementation of the QRS score in the following groups of subjects. Patients who had been studied for possible lung disease with pulmonary tests, including lung volumes, were divided into two groups: group 1 (n = 133), with abnormal tests (emphysema); and group 2 (n = 102), with normal tests (no emphysema). Two other groups were studied: group 3 (positive controls, n = 44), with greater than 3 QRS points for MI on ECG and documented coronary disease with wall motion abnormalities on angiography; and group 4 (negative controls, n = 146), 49 house staff and 97 clinically normal men. A frontal plane P axis greater than 65 separated 90% of patients with emphysema from those without. Of 133 patients with emphysema, 60 (45%) had greater than 3 QRS points for MI on ECG, mainly from Q criteria in aVL and V1-V3; decreased R criteria 1 in V2, V3, and V6; and abnormal R/S criteria in V4-V6. Using HP-ECL, the QRS score was readily modified so that when P axis was greater than 65 these MI size criteria were suppressed. This resulted in a more appropriate incidence of MI diagnoses: 2% (down from 45%) in emphysema patients, no change in specificity, and minor reduction in sensitivity to MI in infarct controls from 100% to 96%.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocardiography↗
PubMed1988

Intra-arterial and cuff blood pressure responses during incremental cycle ergometry.

Brachial intra-arterial blood pressure [systolic (AS) and diastolic (AD)] and cuff blood pressure [systolic (CS) and fourth- and fifth-phase diastolic (CD)] were simultaneously measured by a single observer in 13 middle-aged men during 1-min incremental cycle exercise. On the average, the mean AS exceeded the mean CS by 10 to 11 mm Hg, while the mean AD exceeded the average fourth and fifth CD by 5 and 13 mm Hg, respectively. During incremental exercise, AS, CS, AD, and fourth-phase CD increased, while fifth-phase CD decreased. We also measured intra-arterial blood pressure in nine young adult men smokers during 1-min incremental cycle exercise. In both groups, the average intra-arterial blood pressures increased in a relatively linear fashion from rest to maximal exercise: AS change = 74 +/- 5 mm Hg (SE) and AD change = 28 +/- 3 mm Hg for young men; AS change = 59 +/- 5 mm Hg and AD change = 12 +/- 3 mm Hg for middle-aged men. In this population of middle-aged smokers, intra-arterial mean blood pressure during exercise approximated diastolic plus 2/5 pulse pressure for intra-arterial measures or diastolic plus 1/2 pulse pressure for cuff measures rather than the traditional formula of diastolic plus 1/3 pulse pressure.

Adult↗
PubMed1988

Blood gas quality control materials compared to tonometered blood in examining for interinstrument bias in PO2.

Although large differences in mean values and standard deviations of PO2 between models of blood gas instruments have been found in proficiency testing surveys employing commercial ampuled material, it is unknown whether or not equivalent differences would be found between instruments if a primary standard (tonometered fresh human blood) were used instead of ampules (secondary control specimens). Therefore, we compared the biases (differences between means) of six models of blood gas instruments using five varieties of ampuled quality control materials and a single source of tonometered fresh human blood at three levels of PO2 (67.5, 91.4, and 143.6 mm Hg). All materials correlated positively with blood, thus demonstrating consistency of machine biases. The coefficients of variation measuring blood and a perfluorocarbon mixture (abc) were not different, but were higher for aqueous and hemoglobin-containing mixtures. On average, at the PO2 levels tested, the differences among instruments were slightly smaller with abc than with blood, but larger with aqueous and hemoglobin-containing materials. Because abc "tracks" tonometered blood reasonably well at the PO2 levels tested, instrument differences in PO2 detected with abc are also likely to be seen with clinical blood samples. The other four quality control materials probably overestimate instrument differences in measuring PO2.

Blood Gas Analysis↗
PubMed1988

Penetrating intracranial wood wounds: clinical limitations of computerized tomography.

The case history of a patient with a periorbital penetrating wooden foreign body is presented. The computerized tomography (CT) densities of several different sources of wood were compared using an experimental model. The clinical usefulness and practical limitations of CT in the evaluation of intracranial foreign bodies is discussed, and the management of this type of injury is reviewed.

Brain Injuries↗
PubMed1987

Acute phase reaction, heterogeneity, and microheterogeneity of serum proteins as nonspecific tumor markers in lung cancer.

The acute phase proteins, orosomucoid, ceruloplasmin, antitrypsin, and haptoglobin were measured in serum from 54 patients with lung cancer, 16 patients with benign lung inflammation, and 30 healthy individuals. A statistical correlation was found between tumor size and acute phase protein level, which, however, was ascribed to nonspecific inflammation in the tissues surrounding the tumor. The patients who subsequently could not be radically treated by surgery had higher concentrations of orosomucoid and ceruloplasmin than the radically treated patients. No difference in acute phase protein concentration was found between benign and malignant disease. The glycan-dependent microheterogeneity of orosomucoid and ceruloplasmin was analyzed by crossed affinoimmunoelectrophoresis with lectins, and the patterns of the patients with benign inflammation and malignant disease were different. The heterogeneity of ceruloplasmin was also analyzed by crossed immunoelectrophoresis without lectin. This analysis, combined with the total serum concentration of ceruloplasmin, made it possible to discriminate the 54 cases of malignancy from the 46 cases of nonmalignancy with a sensitivity of 78% and a specificity of 93%. It is suggested that the simple electrophoretic analyses of (micro-)heterogeneity is a valuable supplement to the acute phase profile in isolating high-risk patients and in monitoring radically treated cancer patients for relapse.

Acute-Phase Proteins↗
PubMed1987

Diffusing capacity for carbon monoxide as a predictor of gas exchange during exercise.

In patients with pulmonary disease, the diffusing capacity for carbon monoxide has been used to predict abnormal gas exchange in the lung. However, abnormal values for arterial blood gases during exercise are likely to be the most sensitive manifestations of lung disease. We compared the single-breath diffusing capacity for carbon monoxide at rest with measurements of gas exchange during exercise, including arterial oxygen tension, the alveolar-arterial difference in oxygen tension, the arterial-end-tidal difference in carbon dioxide tension, and the dead-space/tidal-volume ratio in 276 current and former shipyard workers. Sixteen workers had a diffusing capacity for carbon monoxide below 70 percent of predicted; one or more measurements of gas exchange during exercise were abnormal in 14. In contrast, of 96 men who had abnormal gas exchange during exercise, only 14 had a diffusing capacity for carbon monoxide below 70 percent of predicted. Neither the type nor the degree of abnormality in gas exchange could be predicted from the diffusing capacity. We conclude that diffusing capacity for carbon monoxide at rest is a specific but insensitive predictor of abnormal gas exchange during exercise and that, if indicated, measurements of arterial blood gases should be obtained during exercise.

Asbestosis↗
PubMed1987

Relation of oxygen uptake to work rate in normal men and men with circulatory disorders.

The relation between the increase in oxygen uptake (VO2) and increase in work rate (WR) between unloaded pedaling and maximal work during incremental cycle ergometer exercise was studied in normal men, men with uncomplicated systemic hypertension and ambulatory men with various cardiovascular diseases. The postulation was that impaired peripheral oxygen delivery would reduce the ratio of the oxygen utilized relative to work performed. The ratio of increase in VO2 to increase in WR (delta VO2/delta WR) was relatively constant: 10.29 +/- 1.01 ml/min/W in normal men (n = 54) for exercise 6 to 14 minutes in duration with uniform work increments of 15, 20, 25 or 30 W/min, regardless of age. The value in men with uncomplicated systemic hypertension (n = 24) was not significantly different from that of normal men. However, more than half of the men with peripheral vascular disease (n = 7) or pulmonary vascular disease (n = 5) or men who had electrocardiographic abnormalities during exercise (n = 39) had a significantly lower delta VO2/delta WR, 8.29 +/- 1.17 ml/min/W (p less than 0.05) especially evident as maximal work rates were approached. Thus, delta VO2/delta WR during incremental exercise testing is predictable for normal men and a reduction in this ratio indicates cardiovascular dysfunction.

Adult↗
PubMed1987

Quantitative and qualitative binding characteristics of disopyramide in serum from patients with decreased renal and hepatic function.

Protein binding of disopyramide, binding capacities, affinity constants and serum concentrations of alpha 1-acid glycoprotein (AAG) were studied in five groups of patients. A: young healthy volunteers (n = 8); B: elderly patients with minor symptoms of ischaemic heart disease (n = 9); C: patients with cirrhosis of the liver and normal values of coagulation factors (II, VII and X), albumin and immunoglobulin G (n = 8); D: patients with cirrhosis and at least two abnormal of the previously mentioned values (n = 9) and E: eleven patients with severely impaired renal function. Subfractions of AAG (Fr1, Fr2 and Fr3) were determined by affinoimmunoelectrophoresis. AAG concentration was significantly (P less than 0.005) elevated in group E patients and decreased (P less than 0.025) in group D patients. Fr2 is probably associated with the high affinity, first binding site of disopyramide to AAG. Earlier observations of a reduced qualitative binding of disopyramide in patients with cirrhosis can be explained by a significant decrease in Fr2 (P less than 0.001) in group D patients. The protein binding of disopyramide in patients with uraemia was significantly increased due to a significant (P less than 0.005) increase in AAG concentration in spite of a smaller (P less than 0.025) affinity constant. Suggestions for therapeutic drug monitoring based on total serum concentrations are given.

Adult↗
PubMed1987

The role of exercise testing in impairment evaluation.

To examine the usefulness of exercise testing in impairment evaluation, we reviewed the evaluation of 348 asbestos-exposed shipyard workers. We compared work capacity predicted from history, physical examination, chest roentgenogram, resting electrocardiogram, and resting pulmonary function tests with measured work capacity during an incremental cycle exercise test. The predicted work capacity was often incorrect when compared with measured maximal oxygen uptake (VO2). One third (22 of 66) of those predicted to have reduced work capacity had normal measured work capacity, and 46 of 148 workers (31%) predicted to have normal work capacity were found to have low maximal VO2 during exercise. Of 134 men for whom predicted work capacity was uncertain, maximal VO2 during exercise was low in 49 (37%), normal in 81 (60%), and remained indeterminate in 4 (3%). Thus, of the 138 workers who had low measured VO2, 43 were correctly predicted to have normal work capacity, 46 were incorrectly predicted, and the prediction was uncertain in 49. Only a few were limited by respiratory disease, and cardiovascular disorders limited 69% of those with a low maximal VO2 during exercise. Accordingly, resting VC, FEV1, and DLCO had a poor correlation with exercise performance. Finally, we found that resting DLCO was a poor predictor of abnormal exercise AaPO2, dead-space/tidal volume ratio, or arterial end-tidal PCO2 difference. We conclude that exercise testing is needed for accurate work capacity assessment in impairment evaluation. Exercise testing also facilitates the identification of the major limiting system in those with low work capacity.

Asbestosis↗
PubMed1987

Validity of ear oximetry in clinical exercise testing.

Because of suspicion that the ear oximeter might measure the oxyhemoglobin saturation of arterial blood inaccurately during heavy exercise, we made concurrent ear oximetric and blood measurements on 14 consecutive patients with arterial catheters during clinical exercise tests. After correcting for carboxyhemoglobin, the estimated and measured values for the oxyhemoglobin saturation of the blood agreed well, as did resting ear and blood values; however, during heavy exercise, ear oximetric values were falsely elevated in two patients with interstitial pulmonary disease and were falsely depressed in five patients with cardiovascular limitation to exercise. In another patient, ear oximetric values declined during heavy exercise despite mild hyperoxia, suggesting hypoperfusion of the ear. Considering the clinical and physiologic importance of oxyhemoglobin saturation, ear oximetric values during heavy exercise should be cautiously interpreted.

Adult↗
PubMed1987

Thyroid size and goitre frequency in hyperthyroidism.

Thyroid function, the clinical occurrence of goitre and thyroid gland volume, ultrasonically determined, were investigated in 310 consecutive untreated patients with hyperthyroidism. Of 173 patients with Graves' disease (39%), 67 had no goitre, while 53 patients (31%) had a normal thyroid volume. Twenty-three of 91 patients with multinodular glands (25%) had no goitre and ten patients (11%) had a normal thyroid volume. Of 46 patients with solitary autonomous nodules (7%), three had no goitre while six (13%) had a normal thyroid volume. Out of all the hyperthyroid patients (30%), 93 had no clinically detectable goitre, and 69 (22%) had a normal thyroid volume. The lack of a goitre in a large portion of patients with hyperthyroidism could be responsible for delayed diagnosis and subsequent treatment of these patients.

Adolescent↗
PubMed1986

Bronchodilatation and attenuation of exercise-induced bronchospasm by PY 108-068, a new calcium antagonist.

The effect of a new dihydropyridine-derivative calcium antagonist, PY 108-068, on resting and postexercise flow rates was evaluated in 12 adult asthmatic subjects in a double-blind, randomized, placebo-controlled, cross-over study. The study consisted of 2 periods, each lasting for 3 days. For a given period a single dose of PY 108-068 (or placebo) was given orally, 75 mg on the first day and 150 mg on the second and third day. Spirometry was obtained at 30-min intervals thereafter. On Day 3, 75 min after the medication was given, a 6-min treadmill exercise test was performed breathing dry air. The mean maximal FEV1 recorded after 150 mg of PY 108-068 on Day 2 was 15 +/- 4% higher than the daily baseline (p less than 0.05), whereas after placebo the maximal FEV1 value was not different from the daily baseline. Also, the mean FEV1 values, expressed as percent of the daily predrug baseline, were significantly higher at 2 and 3 h after 150 mg of PY 108-068 than the respective values after placebo (110 +/- 4 compared with 95 +/- 1, and 106 +/- 5 compared with 91 +/- 3, respectively). Exercise-induced bronchospasm (EIB), expressed as maximal percent fall in FEV1 from preexercise baseline, was attenuated by PY 108-068 as compared with placebo (% delta FEV1 of 20 +/- 6 and 40 +/- 4, respectively; p less than 0.001). Protection against EIB did not correlate with the resting bronchodilation induced by PY 108-068, but was more likely if the patient had eosinophilia. Thus, PY 108-068 not only attenuates EIB but also causes resting bronchodilation, a unique finding for calcium channel blockers.

Adult↗
PubMed1986

Proficiency testing materials for pH and blood gases. The California Thoracic Society experience.

The California Thoracic Society Blood Gas Proficiency Testing Program distributed ampules from three separate lots of quality control products every three months as unknowns to participating clinical (survey) laboratories and ten selected reference laboratories. For eight quarters, aqueous buffers were distributed. For each lot, PCO2 and pH measurements varied within narrow ranges between laboratories. Concurrently, the PO2 measurements varied widely between reference laboratories as well as survey laboratories, but varied minimally when repeatedly assessed on each reference laboratory machine. Change to a fluorocarbon-containing emulsion as a testing medium resulted in a significant reduction in within model and overall variability for PO2. We attribute this reduction in variability to the higher O2 content and decreased temperature sensitivity for PO2 of the fluorocarbon-containing emulsion. Because we have no evidence that the magnitude of the interinstrument differences in PO2 found with these materials would be found with fresh human blood we recommend that regulatory agencies use the results of proficiency testing for PO2 cautiously.

Blood↗
PubMed1986

Comparison of PY 108-068, a new calcium antagonist, with nifedipine in exercise-induced asthma.

Several calcium antagonists, each with significantly different chemical structures, have demonstrated variable attenuation of exercise-induced asthma. Quantitative comparisons have been hampered by differences in the intensity of challenge and the severity of the underlying disease between groups of patients. In 12 asthmatic adults with relatively severe exercise-induced asthma, we compared the effect of a new calcium antagonist, PY 108-068, in doses of 75 mg and 150 mg with nifedipine (30 mg) and placebo on resting flow rates and flow rates after exercise. Over a three-week period, each patient completed a four-day, randomized, double-blind Latin-square study. After receiving one of four oral drugs, spirometry was repeated every 30 minutes for two hours, followed by a six-minute treadmill exercise test breathing dry air. The exercise tests were well matched for work rate, ventilation, heart rate, and oxygen uptake. Spirometry was then repeated seven times over the next 30 minutes after exercise. Though both 150 mg of PY 108-068 and nifedipine were associated with mild bronchodilation before exercise, only the latter was significant (p less than 0.05). Exercise-induced asthma (expressed as maximal percent fall in the forced expiratory volume in one second from before baseline) was significantly attenuated only by 150 mg of PY 108-068 compared to placebo (24 +/- 13 vs 40 +/- 16; p less than 0.05). Headache, which occurred in six subjects after nifedipine, five after 150 mg of PY 108-068, one after 75 mg of PY 108-068, and none after placebo, was subjectively more severe after nifedipine. We conclude that in these patients, there was a tendency for mild bronchodilation before exercise with both 150 mg of PY 108-068 and nifedipine, but only the 150-mg dose provided significant protection against exercise-induced asthma two hours after the drug.

Adolescent↗
PubMed1985

Influence of rifampicin and isoniazid on the kinetics of phenytoin.

Clearance of phenytoin after i.v. injection of 100 mg was studied in six patients before and after 2 weeks daily treatment with 450 mg rifampicin, and in 14 patients with tuberculosis receiving standard treatment with 450 mg rifampicin, 300 mg isoniazid, and 1200 mg ethambutol daily. Acetylator status was measured by urinary acetylated sulphadimidine. Clearance of phenytoin in patients receiving only rifampicin increased from 46.7 ml min-1 +/- 20.6 ml min-1 to 97.8 ml min-1 +/- 33.4 ml min-1 (P less than 0.01), while clearance in patients on three drugs increased from 47.1 +/- 23.4 ml min-1 to 81.3 ml min-1 +/- 41.6 ml min-1 (P less than 0.01). No significant differences were observed between the six fast acetylators and the eight slow acetylators. Phenytoin kinetics were unchanged after further 3 months of combined treatment. Rifampicin is a strong inducer of the elimination of phenytoin. Combined treatment with isoniazid has no counter-acting effect in either fast or slow acetylators.

Acetylation↗
PubMed1985

Immediate effects of cigarette smoking on cardiorespiratory responses to exercise.

To determine the acute action of cigarette smoking on cardiorespiratory function under stress, the immediate effects of cigarette smoking on the ventilatory, gas exchange, and cardiovascular responses to exercise were studied in nine healthy male subjects. Each subject performed an incremental exercise test to exhaustion on two separate days, one without smoking (control) and one after smoking 3 cigarettes/h for 5 h. The order of the two tests was randomized. Arterial blood gases and pH were measured during rest and all levels of exercise; CO blood levels confirmed the absorption of cigarette smoke. In addition, minute ventilation (VE), end-tidal PCO2 and PO2, O2 uptake (VO2), CO2 production, directly measured blood pressure, electrocardiogram, and heart rate (HR) were recorded every 30 s. The dead space-to-tidal volume ratio (VD/VT), maximal aerobic capacity (VO2max), and anaerobic threshold (AT) were determined from the gas exchange data. Cigarette smoking resulted in a significantly lower VO2max, AT, and VO2/HR (O2 pulse) and a significantly higher HR, pulse-pressure product, and pulse pressure (P less than 0.05) compared with the control. Additionally, a trend toward a higher VD/VT and arterial-end-tidal PCO2 difference was found during exercise after smoking. We conclude that cigarette smoking causes immediate detrimental effects on cardiovascular function during exercise, including tachycardia, increased pulse-pressure product, and impaired O2 delivery. The acute effects on respiratory function were less striking and primarily limited to abnormalities reflecting ventilation-perfusion mismatching.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Lung function and exercise performance in smoking and nonsmoking asbestos-exposed workers.

Evaluation of impairment caused by exposure to an occupational toxin can be complicated by additional exposure to other injurious agents. Because cigarette smoking is common and cigarettes are implicated in obstructive lung disease and cardiovascular diseases, we assessed the contribution of smoking to functional abnormalities in a group of asbestos-exposed shipyard workers. Seventy-three workers who never smoked were paired with 73 current smokers by age and asbestos exposure. Pulmonary function and performance during cycle incremental exercise were compared between the 2 groups. Nonsmokers had significantly higher VC, FEV1, FEV1/VC, and diffusing capacity for carbon monoxide than did smokers. Only 3 of the 73 nonsmokers but 23 of the 73 smokers had a FEV1/VC below the 95% confidence limit of predicted value. The FEF25-75%, on the other hand, failed to identify additional subjects with obstruction not found by the FEV1/VC. During exercise, despite no difference in maximal heart rate, the maximal O2 uptake (VO2max) and oxygen-pulse were lower among smokers. In addition, smokers more frequently had abnormal AaPO2 at maximal exercise. Of 33 smokers who had a VO2max less than 80% of predicted, 16 were judged to have cardiac disease, whereas only 2 appeared to be limited by obstruction. Only 15 of the 73 nonsmokers had a VO2max less than 80%. We conclude that cigarette smoking was the major contributing factor to the obstructive lung disease observed in asbestos workers, and it also had a strong influence on the occurrence, nature, and magnitude of exercise limitation. The history of cigarette smoking has an important effect on the assessment of impairment from asbestos.

Aged↗