Dopamine transporter SPECT using fast kinetic ligands: 123I-FP-beta-CIT versus 99mTc-TRODAT-1.

A comparative study was carried out on two promising presynaptic dopamine transporter single-photon emission tomography (SPECT) radioligands with a fast pharmacokinetic profile, 123I-FP-beta-CIT (FP) and 99mTc-TRODAT-1 (TR), in order to assess their differential diagnostic power in early parkinsonism and their sensitivity for detection of disease progression. This cross-sectional study was conducted on 96 patients with early-stage parkinsonism referred in a tertiary clinical setting. Mean disease duration was 2.0+/-1.3 years, and patients had a modified Hoehn and Yahr (H&Y) stage of 1-2 (average 1.2). Forty-seven patients received TR, and 49 received FP. In both groups, ten patients with normal presynaptic function were included as a control population; all other patients were clinically diagnosed as having idiopathic Parkinson's disease. Groups were matched for gender, age, disease duration and modified H&Y stage. Triple-head gamma camera SPECT was analysed using a semiquantitative index of transporter binding (BI). Discriminant analysis with cross-validation resulted in a maximal classification accuracy for FP of 93% (sensitivity 95% and specificity 86%) for the contralateral putamen BI. For TR, the corresponding values were 87% accuracy, 92% sensitivity and 70% specificity. For FP, disease duration was correlated with both the putamen BI (-8.8%/year, rho=-0.41, P=0.025) and the putamen/caudate ratio (-7.4%/year, rho=-0.51, P=0.004), but for TR no significant correlation was found (all P values >0.5). In conclusion, both FP and TR show high sensitivity in a clinically relevant setting, but FP has superior accuracy for early differential diagnosis of idiopathic parkinsonism and non-degenerative extrapyramidal disorders, as well as better sensitivity for disease follow-up.

RP-HPLC separation of the diastereomers of technetium-99m labelled tropanes and identity confirmation using radio-LC-MS.

99mTc-TRODAT-1 (technetium(V)-oxo-2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-yl]methyl](2-mercaptoethyl)amino]ethyl]]amino]-ethanethiolato(3-)) and 99mTc-TRODAT-M, the 4-methylphenyl derivative of 99mTc-TRODAT-1, are at this moment being evaluated in clinical trials as imaging agents for the central nervous dopamine transporter system. Both compounds are formed as a mixture of two major diastereomers. As the tracer concentration in preparations for clinical investigations is very low (30-150 pmol/ml), identification of these 99mTc-complexes was, up to now, carried out indirectly using X-ray diffraction analysis of the corresponding rhenium complexes which can be synthesized in gram amounts. In this study, we developed a convenient and practical reversed phase HPLC-method for purification and isolation of the respective diastereomers of 99mTc-TRODAT-1 and three of its derivatives using mixtures of solvents which are compatible with biological studies, i.e. aqueous buffers and ethanol. Furthermore, direct identity confirmation of the 99mTc-complexes using radio-LC-MS was successfully elaborated.

An efficient HPLC method for the analysis of isomeric purity of technetium-99m-exametazime and identity confirmation using LC-MS.

99mTc-exametazime (99mTc-d,l-HMPAO, 99mTc-d,l-hexamethylpropyleneamine oxime) is a neutral rather unstable complex of short-lived 99mTc (t(1/2)=6 h) with the d,l-isomer (mixture of D,D- and L,L-isomers) of a bis-amine bis-oxime tetraligand. It is widely used for measurement of regional cerebral perfusion in nuclear medicine. The meso-isomer (D,L-form) should not be present in a preparation as it is not retained in brain and thus does not provide clinically useful information. Meso-HMPAO is removed from the ligand during the synthesis procedure by repeated recrystallization, but can still be present as impurity in d,l-isomer. Due to the lack of a suitable chromatographic method for analysis of the isomeric purity of 99mTc-exametazime preparations, United States Pharmacopoeia 25 (USP 25) prescribes a biological test in rats for quality control purpose. In this study, we developed a suitable high-performance liquid chromatography (HPLC) method which allows to demonstrate the relative amounts of d,l- and meso-isomer in 99mTc-exametazime and so obviates the need for a biodistribution test in animals as part of the quality control. Due to the low concentrations in which 99mTc-d,l-HMPAO is obtained (typically 2-6 ng/ml), confirmation of the identity of 99mTc-d,l-HMPAO in the monograph of the European Pharmacopoeia is now performed only indirectly by TLC and assessment of its retention time on RP-HPLC. To investigate the potential of radio-LC-MS for assessment of the identity of 99mTc-exametazime, 99mTc-d,l-HMPAO and 99mTc-meso-HMPAO prepared using a Tc-rich eluate were analyzed using a radio-LC-MS system equipped with a time-of-flight mass spectrometer with electrospray ionization. The main peak in the radiometric channel coincided with the molecular ion mass of 99mTc-d,l-HMPAO in the mass spectrometer channel and the measured accurate mass differed only by 0.26 ppm from the theoretical mass. The identity of 99mTc-meso-HMPAO was also confirmed. Thus, radio-LC-MS allowed to obtain strong evidence for the structure of 99mTc-d,l-HMPAO and 99mTc-meso-HMPAO at nanomolar concentration. It is concluded that radio-LC-MS can become a sensitive aid in quality control of "no carrier added" radiopharmaceutical preparations.

Preparation and preliminary evaluation of 99mTc-EC-For-MLFK.

For-Met-Leu-Phe-Lys (For-MLFK), a chemotactic peptide that binds with high affinity to granulocytes and monocytes, was labeled with 99mTc using ethylene dicysteine (EC) as the metal chelating system. EC was selected because of the rapid renal excretion of its 99mTc-complex and therefore, was expected to enhance the degree of urinary elimination of the peptide-conjugate. 99mTc-EC-For-MLFK was prepared using a preformed chelate approach. After incubation of 99mTc-EC-For-MLFK with total blood, 68.1% of the labeled peptide was associated with WBC and 86% of this cell-associated activity was bound to granulocytes. Biodistribution studies in normal mice revealed a very fast blood clearance (4.1% and 0.6% of I.D. in blood at respectively 5 and 60 min p.i.). However, elimination of the labeled peptide proceeds mainly via the hepatobiliary system (24.5% of I.D. in liver and 48.8% of I.D. in intestines at 60 min p.i.) and to a much lower degree via the kidneys (17.9% in renal system at 60 min p.i.). From these results, it is concluded that 99mTc-EC-For-MLFK is not suited to image infections, despite its high binding to granulocytes, since it leads to high, non-specific, abdominal activity.

Passage of inhaled particles into the blood circulation in humans.

BACKGROUND: Pollution by particulates has been consistently associated with increased cardiovascular morbidity and mortality. However, the mechanisms responsible for these effects are not well-elucidated. METHODS AND RESULTS: To assess to what extent and how rapidly inhaled pollutant particles pass into the systemic circulation, we measured, in 5 healthy volunteers, the distribution of radioactivity after the inhalation of "Technegas," an aerosol consisting mainly of ultrafine (99m)Technetium-labeled carbon particles (<100 nm). Radioactivity was detected in blood already at 1 minute, reached a maximum between 10 and 20 minutes, and remained at this level up to 60 minutes. Thin layer chromatography of blood showed that in addition to a species corresponding to oxidized (99m)Tc, ie, pertechnetate, there was also a species corresponding to particle-bound (99m)Tc. Gamma camera images showed substantial radioactivity over the liver and other areas of the body. CONCLUSIONS: We conclude that inhaled (99m)Tc-labeled ultrafine carbon particles pass rapidly into the systemic circulation, and this process could account for the well-established, but poorly understood, extrapulmonary effects of air pollution.

Passage of intratracheally instilled ultrafine particles from the lung into the systemic circulation in hamster.

The mechanisms of particulate pollution-related cardiovascular morbidity and mortality are not well understood. We studied the passage of radioactively labeled ultrafine particles after their intratracheal instillation. Hamsters received a single intratracheal instillation of 100 microg albumin nanocolloid particles (nominal diameter < or = 80 nm) labeled with 100 microCi technetium-99m and were killed after 5, 15, 30, and 60 min. In blood, radioactivity, expressed as percentage of total body radioactivity per gram blood, amounted to 2.88 +/- 0.80%, 1.30 +/- 0.17%, 1.52 +/- 0.46%, and 0.21 +/- 0.06% at 5, 15, 30, and 60 min, respectively. Thin-layer chromatography showed only one peak of radioactivity corresponding to unaltered (99m)Tc-albumin nanocolloid. In the liver, radioactivity, expressed as percentage of total radioactivity per organ, amounted to 0.10 +/- 0.07%, 0.23 +/- 0.06%, 1.24 +/- 0.27%, and 0.06 +/- 0.02% at 5, 15, 30, and 60 min, respectively. Lower values were observed in the heart, spleen, kidneys, and brain. Dose dependence was assessed at 30 min following instillation of 10 microg and 1 microg (99m)Tc-albumin per animal (n = 3 at each dose), and values of the same relative magnitudes as after instillation of 100 microg were obtained. We conclude that a significant fraction of (99m)Tc-albumin, taken as a model of ultrafine particles, rapidly diffuses from the lungs into the systemic circulation.

Scintigraphic evaluation in rabbits of nasal drug delivery systems based on carbopol 971p((R)) and carboxymethylcellulose.

The residence time of apomorphine mucoadhesive preparations incorporating 99mTc labeled colloidal albumin in rabbit nasal cavity was evaluated by gamma scintigraphy. This technique was used to compare the nasal clearance of preparations based either on Carbopol 971P((R)) or lactose (control), each with and without apomorphine, or carboxymethylcellulose with apomorphine. The planar 1-min images showed an excipient-dependent progressive migration of radioactivity with time from the nasal cavity to the stomach and intestine. Thirty minutes post insufflation, the percentages of the formulations cleared from the nasal cavity were 47% for lactose, 26% for lactose/apomorphine, 10% for Carbopol 971P((R)), and 3% for both Carbopol 971P((R))/apomorphine and carboxymethylcellulose/apomorphine. Three hours post insufflation, the percentages of the formulations cleared from the nasal cavity were 70% for lactose, 58% for lactose/apomorphine, 24% for Carbopol 971P((R)), 12% for Carbopol 971P((R))/apomorphine, and 27% for carboxymethylcellulose/apomorphine. Apomorphine inhibited nasal mucociliary clearance since migration of the radioactivity administered with apomorphine containing preparations was in all cases slower than that of the corresponding powder without apomorphine. The peak plasma concentration of apomorphine was attained while all the formulations were still within the nasal cavity. The use of mucoadhesive polymers such as Carbopol 971P((R)) or carboxymethylcellulose in nasal dosage forms increases their residence time within the nasal cavity and provides the opportunity for sustained nasal drug delivery.

Self-injection ictal SPECT during partial seizures.

The authors compared ictal SPECT injection performed by medical personnel with self-injection ictal SPECT in six patients with refractory temporal lobe epilepsy. Self-injection was safe and started faster. Self-injection subtraction ictal SPECT coregistered to MRI (SISCOM) was localizing in three patients who had a complex partial seizure, but only one of three patients who had a simple partial seizure, which may limit its usefulness in clinical practice. The localizing information of self-injection was better in three patients, and obviated the need for depth-EEG studies in one patient.

Synthesis and biological evaluation of the four isomers of technetium-99m labeled ethylenecysteamine cysteine ((99m)Tc-ECC), the mono-acid derivative of (99m)tc-L,L-ethylenedicysteine.

A few years ago (99m)Tc-ethylenedicysteine ((99m)Tc-L,L-EC) had been proposed as an interesting substitute for technetium-99m labeled mercaptoacetyltriglycine (MAG3) as renal function tracer agent. It possesses in its structure two carboxylate functions and is in this respect different from other renal tracers such as (99m)Tc-N, N'-bis-(mercaptoacetyl)-2,3-diaminopropionate ((99m)Tc-CO(2)DADS), (99m)Tc-MAG3, and Hippuran, which have only one carboxylic group. To study whether both carboxylic acid groups of (99m)Tc-L,L-EC contribute to the efficient renal handling of this compound we synthesized and biologically evaluated the technetium-99m labeled isomers of L- and D-ethylenecysteamine cysteine (ECC), the mono-acid derivative of (99m)Tc-L,L-EC. Labeling of L-ECC or D-ECC with (99m)Tc using a direct or exchange labeling method yields for each of them two diastereomeric (99m)Tc complexes (A and B, in the order of elution during reversed phase high performance liquid chromatography) in relative amounts depending on the pH during labeling. In mice, all four isomers of (99m)Tc-ECC (LA, LB, DA, and DB) are cleared rapidly from the blood, mainly by the renal system. The isomers LB and DB show the most efficient renal handling, but none of the mono-acid derivatives has a urinary excretion rate as high as that of (99m)Tc-L,L-EC. The renal handling of the isomers of (99m)Tc-ECC is partly due to tubular secretion because the urinary excretion of these compounds is significantly lower in mice pretreated with probenecid. In the baboon, isomers DA and DB show a plasma clearance comparable to that of (99m)Tc-L,L-EC. The plasma clearance of isomers LA and LB is lower but still comparable to or higher than that of (99m)Tc-MAG3. In a human volunteer, isomer DB shows a plasma clearance rate only slightly lower than that of (99m)Tc-L,L-EC. Thus, it appears that the presence of one carboxylate in (99m)Tc-EC-like compounds can be sufficient for efficient renal handling. However, it is also evident that the configuration at the chiral carbon atom and the orientation of the oxotechnetium core determine in a significant way the biological characteristics.

Coronary radiation therapy with liquid rhenium-186: a first clinical experience.

BACKGROUND: Coronary radiation therapy (CRT) is a new, attractive approach for the treatment and prevention of restenosis after percutaneous coronary interventions (PCI). The RadioCath device consists of a standard balloon dilatation catheter that can be charged with a solution of sodium 186Re perrhenate, a predominant beta emitter. The safety and performance of this new device was evaluated in a pilot trial. METHODS AND RESULTS: Thirty-three patients with a de novo lesion in a native coronary artery were treated with the RadioCath device after successful angioplasty. The average dwell time to deliver a dose of 20 Gy at 0.5 mm into the vessel wall was 418+/-64 seconds. The treatment was well tolerated by most of the patients. In 79%, only one inflation cycle was required to deliver the prescribed dose. There were two procedural device-related complications (5.9%) and three minor procedural related in-hospital complications (9%). CONCLUSIONS: CRT using a balloon catheter device, charged with a sodium 186Re perrhenate solution, seems feasible and safe. Clinical and angiographic 6-month follow-up data are pending.

Synthesis and evaluation of the (99m)tc-complexes of L-cysteine acetyldiglycine (a hybrid of MAG3 and L,L-EC) and of L-beta-homocysteine acetyldiglycine.

L-Cysteine acetyldiglycine (L-CAG2), a hybrid compound of L,L-EC and MAG3, and its L-beta-homocysteine analogue L-HAG2 were synthesized. After labeling with (99m)Tc, (99m)Tc-L-CAG2 and (99m)Tc-L-HAG2 gave two peaks on high performance liquid chromatography. Urinary excretion of both isomers of (99m)Tc-L-CAG2 and (99m)Tc-L-HAG2 was slower than for the "parent" complexes (99m)Tc-MAG3 or (99m)Tc-L,L-EC. Isomer B of (99m)Tc-L-CAG2 showed pronounced kidney retention in mice (57% of ID in kidneys at 30 min postinjection), but further evaluation in baboon did not reproduce this phenomenon.

Reduction of contamination risks during clinical studies with technegas.

During patient studies with the Technegas equipment in our department, we regularly detected small to considerable contaminations of the operator and in the area surrounding the apparatus. These contaminations were found to be of different origin: residual activity in the tubing from the apparatus to the patient which diffuses after deconnection, residual activity and small particles of the destroyed carbon crucible in the apparatus which are dispersed during opening of the door of the gas preparation chamber, leakage at the patient site during studies in uncooperative patients and a dysfunctioning valve inside the apparatus. To reduce the contamination risks, we made some adaptations to the apparatus. In the first place, the dysfunctioning valve was replaced. In addition, a powerful air exhaust pump with an efficient filter was installed. It was connected with (1) a newly installed transparent box in front of the door of the gas preparation chamber, (2) a dome on a flexible arm which can be positioned above the patient's face during the examination and (3) a nipple on which the mouthpiece can be placed after the study. After these adaptations, a study showed the absence of measurable contamination on the clothing of the personnel handling the apparatus. Occasionally, considerable contamination was still measured on the gloves worn during filling of the carbon boat with generator eluate, but only small contaminations (up to 9.25 kBq) were measured on the mouthmask worn by the operator during administration of the Technegas. This results in a maximum effective dose equivalent from activity deposited in the lungs of 0.008 microSv per study. The total body dose of the operator from external radiation for one Technegas examination was determined to be 2 microSv. The highest dose rate was measured during filling of the crucible (0.2 mSv/h).

Importance of the two ester functions for the brain retention of 99mTc-labelled ethylene dicysteine diethyl ester (99mTc-ECD).

99mTc-ethylene dicysteine diethyl ester (99mTc-L,L-ECD) is a neutral lipophilic tracer agent that crosses the blood-brain barrier and is retained in the brain of primates following enzymatic hydrolysis of one of the ester functions to the ionized mono-ester, mono-acid metabolite. Up to now, it is not clear whether the second ethylcarboxylate group is essential for brain uptake and retention. Therefore, we have synthesized and studied two derivatives of 99mTc-L,L-ECD that contain only one ethylcarboxylate function, namely 99mTc-labelled L- and D-ethylene cysteamine cysteine ethyl ester (99mTc-ECCE). Direct labelling of L- or D-ECCE at neutral pH and room temperature resulted for each of them in the formation of two probably diastereomeric 99mTc-complexes in a 1:1 ratio. This means that four different isomers could be isolated. The 99mTc-labelled complexes formed after labelling ECCE (A and B, in order of elution during HPLC) are slightly less lipophilic than 99mTc-L,L-ECD. In mice, all four isomers show a low brain activity at 10 min post injection (p.i.), approximately 0.1% to 0.3% of the injected dose versus 0.9% for 99mTc-L,L-ECD. The clearance from the blood is comparable with (isomers LA and LB) or slower (isomers DA and DB) than that of 99mTc-L,L-ECD. Isomers LA and DA show high liver uptake and rapid excretion to the intestines. Both 99mTc-ECCE-LB and 99mTc-ECCE-DB, the most lipophilic isomers, are cleared from the blood mainly by the kidneys and excreted more efficiently to the urine. 99mTc-ECCE-LB is characterized by a surprisingly high heart uptake (about 1.5% of i.d.) at 10 min p.i. versus 1.0% for 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) and 0.2-0.3% for the other isomers, but also lung uptake is relatively high. In the baboon, brain and heart uptake of isomers LA and LB of 99mTc-ECCE were negligible. Activity concentrated mostly in the hepatobiliary system for isomer LA and in the renal system for isomer LB. The results indicate a clear difference in biological behaviour between 99mTc-L,L-ECD and the four isomers of 99mTc-ECCE. This shows that the presence of both ester functions in 99mTc-L,L-ECD is an essential structural requirement for its brain uptake and retention in primates.

Effect of clopidogrel on naproxen-induced gastrointestinal blood loss in healthy volunteers.

The effect of clopidogrel, a potent inhibitor of platelet aggregation, on naproxen-induced faecal blood loss was investigated in 30 healthy volunteers in a randomized, double-blind, placebo-controlled, two parallel treatment groups study. All subjects first received naproxen 250 mg b.i.d. during 7 days, after which they were randomly allocated to additionally receive either clopidogrel 75 mg once daily (n = 15) or matching placebo (n = 15) for 11 days. Faecal blood loss was measured by the 51Cr-labelled erythrocyte method during the last four days of each of the four study periods, i.e. baseline, treatment with naproxen alone, combined treatment and wash-out. Mean daily faecal blood loss was below 0.5 ml/day during the baseline period in both treatment groups and increased during treatment with naproxen alone to (mean +/- SD) 1.14 +/- 0.58 ml/day in the naproxen + placebo group and to 1.93 +/- 1.51 ml/day in the naproxen + clopidogrel group. Addition of clopidogrel to naproxen treatment was associated with an increase of the mean daily blood loss to 6.83 +/- 9.32 ml/day, which was statistically significantly higher than 1.75 +/- 1.40 ml/day observed during treatment with naproxen + placebo. During the wash-out period, mean daily blood loss decreased to 0.98 +/- 0.51 ml/day in the naproxen + placebo group and to 1.07 +/- 0.46 ml/day in the naproxen + clopidogrel group. Based on these results, it can be concluded that clopidogrel increases naproxen-induced gastrointestinal blood loss in healthy volunteers. Caution should therefore be called for when these drugs are coadministered.

99Tcm-dimercaptopropionyl-HSA prepared from a labelling kit: preliminary investigations as a blood pool agent.

The blood retention of 99Tcm-dimercaptopropionyl human serum albumin (99Tcm-DMP-HSA), prepared from a kit, was compared with that of five other 99Tcm-labelled blood pool tracers in two healthy volunteers. 99Tcm-DMP-HSA showed an almost identical behaviour to in vitro labelled red blood cells (RBCs), which are generally considered the reference standard for blood pool agents. The mean apparent blood mass of 99Tcm-DMP-HSA was 2.1% higher 10 min post-injection (p.i.) than that of in vitro 99Tcm-RBCs, 2.0% higher 30 min p.i., 4.7% higher 60 min p.i. and 2.3% higher 120 min p.i. In vivo labelling of RBCs yielded a labelling efficiency of 75-98%, depending on the stannous agent used. About 20 min after pertechnetate administration, the intravascular activity as a percentage of injected dose stabilized at levels close to that of in vitro labelled RBCs. One commercially available 99Tcm-HSA kit was found to be unsuitable as a blood pool tracer. As 99Tcm-DMP-HSA offers the same practical advantages as 99Tcm-HSA, but better biological characteristics, it shows promise as a new tracer for radionuclide ventriculography and further large-scale investigations are warranted.

Characteristics and biological behaviour of 99mTc-labelled hydroxyacetyltriglycine, a potential alternative to 99mTc-MAG3.

Substitution of the oxidation-sensitive thiol function of mercaptoacetyltriglycine (MAG3) by a hydroxyl group yields a tetraligand (hydroxyacetyltriglycine or HAG3) which is almost insensitive to oxidation and has the advantage over MAG3 that it can be stored safely without protection of the alcohol function. We found that deprotected HAG3 could be directly labelled at alkaline pH (pH>/=11.5) and room temperature in high yield (>95%). Results of electrophoresis experiments suggested a comparable structure for 99mTc-HAG3 and 99mTc-MAG3, namely binding of an oxotechnetium(V)core via three deprotonated amides and a deprotonated hydroxyl group. Biodistribution studies in mice at 10 min and 30 min p.i. showed a slightly higher urinary excretion, a faster renal transit and a significantly lower hepatobiliary handling for 99mTc-HAG3 than for 99mTc-MAG3. In a baboon, the 1-h plasma clearance of 99mTc-HAG3 was clearly higher than that of 99mTc-MAG3. Its plasma protein binding was in the same order as that of Hippuran and much lower than that of 99mTc-MAG3. Evaluation in a human volunteer confirmed the favourable biological characteristics of 99mTc-HAG3, namely a rapid renal excretion, a high 1-h plasma clearance and a negligible hepatobiliary handling. The results indicate that 99mTc-HAG3 may be an easy-to-prepare and practical substitute for 99mTc-MAG3 with improved renal excretion characteristics.

Influence of a 99mTcN core on the biological and physicochemical behavior of 99mTc complexes of L,L-EC and L,L-ECD.

99mTc-nitrido complexes of L,L-ethylene dicysteine (99mTcN-L,L-EC) and 99mTcN-L,L-ethylene dicysteine diethylester (99mTcN-L,L-ECD) were prepared and their characteristics compared to those of the respective 99mTc-oxo complexes. 99mTcN-L,L-EC and 99mTcO-L,L-EC migrate to similar extents during electrophoresis at pH 12, but, at pH6, 99mTcN-L,L-EC migrates further than 99mTcO-L,L-EC. Renal excretion of 99mTcN-L,L-EC is inferior to that of 99mTcO-L,L-EC, indicating that the TcN-glycine sequence has lower affinity for the renal tubular system. Both 99mTcO-L,L-ECD and 99mTcN-L,L-ECD are neutral, but 99mTcN-L,L-ECD is hydrophilic and shows minimal brain uptake in both mice and the baboon.

The effect of long-term treatment with spironolactone on variceal pressure in patients with portal hypertension without ascites.

The effect of spironolactone on esophageal variceal pressure (VP) in patients without ascites was investigated. VP was assessed using a noninvasive endoscopic gauge. Spironolactone was administered during a 6-week period at a dosage of 100 mg/d. This treatment decreased VP from 16.8 +/- 1.9 (SD) to 14.1 +/- 2.7 mm Hg (P < .001) in a group of 12 patients and from 18.6 +/- 2.1 to 13.7 +/- 4.1 mm Hg (P < .01) in another group of 8 patients who still had high VP despite chronic intake of propranolol. In both groups, placebo administration to 12 and 8 comparable patients did not significantly alter VP. Spironolactone induced a significant reduction of plasma volume (42.1 +/- 5.5 to 36.1 +/- 6.6 mL/kg body weight, P < .01) and of the concentration of alpha-atrial natriuretic peptide (alpha-ANP) (39.8 +/- 22 to 27.7 +/- 20 pg/mL, P < .01); in addition, a pronounced increase in plasma renin activity (PRA) (1.1 +/- 0.9 to 7.5 +/- 3.4 ng/mL/h, P < .001) was induced by the treatment. No significant changes in systemic hemodynamics were observed during the studies. Severe side effects were not observed except for a high incidence (55%) of painful gynecomasty in the male patients. In conclusion, chronic spironolactone administration effectively lowers VP, even in patients under chronic propranolol therapy. The combination of propranolol and spironolactone deserves further study as a prophylactic therapy of variceal hemorrhage, but development of gynecomasty might be a problem. Finally, we confirmed the reproducibility of VP measurements with the noninvasive gauge in chronic conditions.