Pulmonary diffusion capacity for carbon monoxide (DLCO), regional electrical impedance (Z0), and the distribution of technetium-99m-labeled erythrocytes together with concentration of plasma atrial natriuretic peptide (ANP) were determined before and after a 6-min "all-out" row in nine oarsmen and in six control subjects. Two and one-half hours after exercise in the upright seated position, DLCO was reduced by 6 (-2 to 21; median and range) %, the thoracic-to-thigh electrical impedance ratio (Z0 thorax/Z0 thigh) rose by 14 (-1 to 29) %, paralleled by a 7 (-3 to 11) % decrease and a 3 (-5 to 12) % increase in the thoracic and thigh blood volume, respectively. These responses were associated with a decrease in the plasma ANP concentration from 15 (13-31) to 12 (9-27) pmol/l (P < 0.05). Similarly, in the supine position, Z0 thorax/Z0 thigh increased by 10 (-5 to 28) % when DLCO was reduced 12 (6-26) % (P < 0.05), whereas DLCO remained stable in the control group. The increase in Z0 thorax/Z0 thigh and the corresponding redistribution of the blood volume in both body positions show that approximately one-half of the postexercise reduction of DLCO is explained by a decrease in the pulmonary blood volume. The role of a reduced postexercise central blood volume is underscored by the lower plasma ANP, which aids in upregulating the blood volume after exercise in athletes.

Correct staging is crucial for the management and prognosis of patients with malignant melanoma. The aim of this prospective study was to compare staging by whole-body positron emission tomography using fluorine-18 fluorodeoxyglucose (18F-FDG) with staging by conventional methods. Thirty-eight patients with malignant melanoma of clinical stage II (local recurrence, in-transit and regional lymph node metastases) or III (metastases to other sites than in stage II) were included in the study. The results of the PET scans were compared with those obtained by clinical examination, computed tomography, ultrasound, radiography, and liver function tests and histology or clinical follow-up. With 18F-FDG PET we found for all foci a sensitivity of 97% and a specificity of 56%, compared with 62% and 22%, respectively, when using routine methods. For intra-abdominal foci, the sensitivity and specificity were 100% for both 18F-FDG PET and routine methods. Corresponding figures for pulmonary/intrathoracic foci were 100% and 33%, respectively. Of the patients included in this study, 34% would not have been staged correctly by conventional methods alone. We conclude from this study that 18F-FDG PET is a sensitive method superior to conventional methods for detecting widespread metastases from malignant melanoma. Mutilating surgery of no benefit can thereby be avoided. 18F-FDG PET is useful as a supplement to clinical examination in melanoma staging.

Physical work capacity was evaluated by a multistage bicycle exercise test in 29 patients, 22 men and seven women aged 35-61 years (mean 49) with alcoholic liver cirrhosis and in a sex- and age-matched control group. The maximal work load was reduced in the patient group, mean 122 vs. 186 watts in men (P less than 0.001), and 60 vs. 119 watts in women (P less than 0.005). Resting heart rate was higher in patients (91 vs. 78 beats X min-1, P less than 0.005), and the maximal heart rate was lower (159 vs. 170 beats X min-1, P less than 0.001) compared with controls. Thirteen of 29 (45%) patients compared with 5 of 29 (17%) control subjects had an increase in left ventricular ejection fraction of less than or equal to 5% during exercise (P less than 0.05). The present results suggest that an impaired capacity of the cardiac function to respond adequately to physical stress may at times contribute to the reduced physical work capacity seen in patients with alcoholic liver cirrhosis.

After an intravenous injection of a tracer that is removed from the body solely by filtration in the kidneys, the glomerular filtration rate (GFR) can be determined from its plasma clearance. The method requires a great number of blood samples but collection of urine is not needed. In the present investigation the total plasma clearance of 51Cr-EDTA (ethylenediaminetetra-acetate) was assessed from 13 blood samples taken 5-300 min post-injection in 44 adult patients with GFR greater than 15 ml min-1. In 34 of these patients the plasma clearance of 99Tcm-DTPA (diethylenetriaminepenta-acetate) was determined simultaneously. Using these clearance values as reference the accuracy of six simplified methods were studied: five single-sample methods and one five-sample method. The standard error of estimate (SEE) of the single-sample methods ranged from 4.2 to 7.5 ml min-1 using EDTA, and from 3.8 to 6.3 ml min-1 using DTPA. SEE of the five-samples method was 3.0 ml min-1 (EDTA) and 3.1 ml min-1 (DTPA). The single-sample methods given by Christensen & Groth (1986) and by Tauxe (1986) are recommended for daily use, as SEE was small even at low GFR values. In patients with GFR less than 80 ml min-1, in whom a highly accurate determination is needed, a multiple samples method is recommended, e.g., Brøchner-Mortensen (1972).

Left ventricular performance was studied non-invasively in 24 chronic alcoholics without liver disease. Twelve patients who had abstained from drinking for at least one month (group A) and 12 sex and age matched patients who had ceased drinking during the preceding 24 hours (group B) were studied at rest and during 50% submaximal exercise. Cardiac output and stroke volume were measured by first passage and left ventricular ejection fraction by multigated radionuclide cardiography. Twelve healthy sex and age matched controls were also studied. Haemodynamic variables were similar in group A and the controls, except that in group A left ventricular end systolic volume index did not decrease during exercise. In group B the heart rate was increased both at rest and during exercise and plasma noradrenaline concentrations were increased. The stroke volume index did not increase significantly during exercise in group B. In addition, the increase in left ventricular ejection fraction was smaller in group B than in controls. End systolic contraction was reduced in group B patients and diastolic blood pressure was increased. These results suggest that cardiac abnormalities in chronic alcoholics may be reversed after cessation of drinking if no chronic liver disease is present. Recent alcohol consumption increases sympathetic nervous activity, impairs cardiac contractility, and increases afterload during physical stress.

1. In plasma samples from normal subjects and patients with untreated essential hypertension, the concentration of inactive renin (as measured after acidification) was on average 4–5 times higher than the concentration of active renin (as measured without acidification). 2. Plasma angiotensin II concentration was correlated to active renin but not to inactive renin. 3. A hyperacute stimulation induced by infusion of saralasin resulted in a marked rise of active renin, whereas inactive renin remained unchanged. 4. An acute stimulation induced by frusemide and ambulation led to a considerable rise in active renin and a slight, but significant, rise of inactive renin. 5. Stimulation with oral thiazide over 5 days induced a seven-fold rise of active renin, with a doubling of inactive renin. Thiazide treatment for 3 months led to a four-fold rise of active renin and a three-fold rise of inactive renin. 6. There was no difference between the concentrations of inactive renin in systemic plasma, ipsilateral and contralateral renal venous plasma in 12 patients with renovascular hypertension, neither before nor after infusion of saralasin with the associated fall in blood pressure. 7. We conclude that the time constants pertinent to secretion or release of active and inactive renin in man are of different orders of magnitude.

We tested the hypothesis that low whole-body insulin sensitivity in patients with ischaemic heart disease and impaired left ventricular (LV) function is associated with abnormalities of insulin-mediated myocardial glucose uptake affecting outcome after coronary bypass surgery (CABG). We studied 29 patients with ischaemic heart disease and impaired LV ejection fraction (EF) and age-matched healthy volunteers ( n = 30). As assessed by euglycaemic glucose-insulin clamp, 15 patients had a low and 14 a normal whole-body insulin sensitivity. Using positron emission tomography, patterns of fluorine-18 fluorodeoxyglucose and nitrogen-13 ammonia uptake in addition to quantified glucose uptake, blood flow and hyperaemic blood flow were assessed before CABG in 16 myocardial segments of the left ventricle. Major adverse cardiac events and LVEF were evaluated 7 months after CABG. Glucose uptake in normokinetic PET-normal myocardium was found to be higher in patients with normal whole-body insulin sensitivity ( P < 0.001), whereas in patients with low whole-body insulin sensitivity more segments displayed a pattern of reduced glucose uptake in normoperfused myocardium (PET-reverse mismatch) ( P < 0.05). Hyperaemic blood flow was impaired in both patient groups. A major cardiac event after CABG could partly be predicted by the LV extent of normoperfused segments with PET-reverse mismatch. We conclude that low whole-body insulin sensitivity in patients with ischaemic heart disease and impaired LV function is associated with impaired insulin-mediated myocardial glucose uptake, which is partially predictive of a worse outcome after CABG.

Myocardial perfusion single-photon emission tomographic (SPET) imaging has been shown to be sensitive in the detection of coronary artery disease (CAD), whereas its specificity has been suboptimal. The aim of the present study was to study the frequency of abnormal bull's eye perfusion defects in a large age-stratified group of healthy subjects undergoing myocardial SPET assessed by comparison with two existing commercially available reference databases. One hundred and twenty-eight healthy volunteers (76 males and 52 females) with a less than 5% likelihood of CAD underwent rest and exercise technetium-99m sestamibi SPET. The false-positive response rate, defined as a significant reversible defect, was 12% when compared to the CEqual database and 29% when compared to the Cedars-Sinai database. With the CEqual program, rest defects occurred in 12% of the subjects. Defects occurred more often in women than in men, but the difference did not attain statistical significance. Significant defects were most frequent in the inferior wall and in women in the anterior wall as well. The distribution of defects was independent of age. Our results suggest that the specificity of 99mTc-sestamibi myocardial SPET using commercially available reference files is suboptimal. The risk of obtaining a false-positive test result in subjects undergoing 99mTc-sestamibi myocardial SPET with a very low likelihood of CAD was higher than anticipated. With both reference files false-positive test results were most frequently observed in the inferior wall. Our data suggest that commercial reference files for myocardial SPET need to be optimised, and should be used with caution. The use of attenuation correction may prove to be a major step forward.