Systemic β-Adrenergic Receptor Activation Augments the ex vivo Expansion and Anti-Tumor Activity of Vγ9Vδ2 T-Cells

TCR-gamma delta (γδ) T-cells are considered important players in the graft-vs.-tumor effect following allogeneic hematopoietic cell transplantation (alloHCT) and have emerged as candidates for adoptive transfer immunotherapy in the treatment of both solid and hematological tumors. Systemic β-adrenergic receptor (β-AR) activation has been shown to mobilize TCR-γδ T-cells to the blood, potentially serving as an adjuvant for alloHCT and TCR-γδ T-cell therapy. We investigated if systemic β-AR activation, using acute dynamic exercise as an experimental model, can increase the mobilization, ex vivo expansion, and anti-tumor activity of TCR-γδ T-cells isolated from the blood of healthy humans. We also sought to investigate the β-AR subtypes involved, by administering a preferential β1-AR antagonist (bisoprolol) and a non-preferential β1 + β2-AR antagonist (nadolol) prior to exercise as part of a randomized placebo controlled cross-over experiment. We found that exercise mobilized TCR-γδ cells to blood and augmented their ex vivo expansion by ~182% compared to resting blood when stimulated with IL-2 and ZOL for 14-days. Exercise also increased the proportion of CD56+, NKG2D+/CD62L-, CD158a/b/e+ and NKG2A- cells among the expanded TCR-γδ cells, and increased their cytotoxic activity against several tumor target cells (K562, U266, 221.AEH) in vitro by 40-60%. Blocking NKG2D on TCR-γδ cells in vitro eliminated the augmented cytotoxic effects of exercise against U266 target cells. Furthermore, administering a β1 + β2-AR (nadolol), but not a β1-AR (bisoprolol) antagonist prior to exercise abrogated the exercise-induced enhancement in TCR-γδ T-cell mobilization and ex vivo expansion. Furthermore, nadolol completely abrogated while bisoprolol partially inhibited the exercise-induced increase in the cytotoxic activity of the expanded TCR-γδ T-cells. We conclude that acute systemic β-AR activation in healthy donors markedly augments the mobilization, ex vivo expansion, and anti-tumor activity of TCR-γδ T-cells and that some of these effects are due to β2-AR signaling and phenotypic shifts that promote a dominant activating signal via NKG2D. These findings highlight β-ARs as potential targets to favorably alter the composition of allogeneic peripheral blood stem cell grafts and improve the potency of TCR-γδ T-cell immune cell therapeutics.

Oral β-blockade in relation to energy expenditure in clinically stable patients with liver cirrhosis: a double-blind randomized cross-over trial

Elevated resting energy expenditure (REE) is seen in liver cirrhosis and is associated with reduced transplant-free survival. Non-selective β-blockers reduce REE in acute hypermetabolic conditions. We examined whether non-selective β-blockers reduce REE in patients with stable liver cirrhosis. Twenty-two stable cirrhotic patients (Child-Pugh grading: 19A, 2B, 1C) were randomized to 3-month treatment with nadolol (titrated to decrease resting pulse rate by 20%) or placebo and after a 1-month washout period crossed to the alternative treatment for a further 3 months. REE was measured by indirect calorimetry and total body protein by neutron activation analysis at the beginning and end of each 3-month period of treatment. A predicted REE was calculated for each patient based on total body protein. A measured to predicted REE ratio >1.22 indicated significantly elevated REE. The primary outcome was REE at the end of 3-month treatment with nadolol compared with placebo. Elevated REE was seen in one patient at study entry. After 3 months on placebo REE was 1506±40 (SEM) kcal/d and on nadolol, 1476±40 kcal/d, a mean reduction of 31±16 kcal/d (P=.076). Total body protein changes were not significant. Nadolol was well tolerated with no increase in the rate of adverse events. In stable cirrhotic patients, nadolol was not associated with reduction in REE. A larger, longer-term study with different eligibility criteria is required to investigate whether this treatment offers benefits additional to its use for prevention of variceal hemorrhage.

The effects of acute and chronic nadolol treatment on β2AR signaling in HEK293 cells

Nadolol (NAD) is a β-adrenergic receptor blocker with inverse agonist activity at βARs. Previous studies in our laboratory showed that chronic treatment with NAD decreased airway resistance response (R (aw)) to the muscarinic agonist methacholine in a murine model of asthma while acute treatment with NAD increased R (aw) (Callaerts-Vegh et al., Proc Natl Acad Sci U S A 101:4948-4953, 2004). Chronic treatment with NAD also caused decreased airway inflammation and mucin content in a murine asthma model (Nguyen et al., Am J Respir Cell Mol Biol 38:256-262, 2008). In this study, we examined the effects of nadolol on β(2)AR levels and signaling components downstream of the β(2)AR using a line of HEK293 cells expressing human β(2)ARs. Chronic treatment with NAD increased β(2)AR protein levels and decreased receptor degradation, consistent with receptor stabilization by the inverse agonist. Basal cAMP levels decreased after 5 min of treatment with NAD but increased after a 24-h treatment. A 5-min treatment with NAD decreased forskolin-stimulated phosphorylation at the β(2)AR PKA site Ser 262 while a 24-h treatment with NAD increased it. In contrast, chronic treatment with NAD had no effect on phosphorylation of the β(2)AR GRK site at Ser 355, 356. Chronic treatment with NAD upregulated cellular levels of G(α)s but had no effect on G(α)i. Chronic NAD treatment therefore increases cellular cAMP levels by mechanisms that include the upregulation of β(2)AR and G(α)s. This effect may explain in part the beneficial effects of chronic nadolol treatment on airway contractility.

[Beta blockers in migraine prophylaxis]

Beta blockers (beta-adrenoceptor blockers) are known to be used for the prophylactic treatment of migraine. The improvement of migraine in the patients who recieved propranolol for angina pectoris revealed the effectiveness of propranolol in migraine prophylaxis. Many clinical trials have confirmed that propranolol is effective in the prophylactic treatment of migraine. Other beta-blocking drugs, namely nadolol, metoprolol, atenolol, timolol and bisoprolol, have also been demonstrated to be effective in the prophylaxis of migraine. In contrast, several beta blockers with intrinsic sympathetic activity (ISA), such as alprenolol, oxprenolol, pindolol and acebutolol, have not been demonstrated to be effective in migraine prophylaxis. In this review, we have descrived the pharmacologic background and pharmacokinetics of the beta blockers that demonstrated a prophylactic effect for migraine will be described. We have also reviewed the results of clinical trials of beta-blocking drugs for migraine.

Effect of nadolol injected prior to CRH on stress-induced plasma corticosterone level in rat

The proposed research is the part of our investigation of the role of catecholamines in the alterations provoked by stress. Especially, we elucidate if Nadolol injected prior to CRH ICV has some effect on plasma corticosterone level. 15 mg/kg of Nadolol (the dose sufficient to prevent CRH-induced increases in heart-rate for 2 hr), dissolved in saline was administered intraperitoneally, 30 minutes prior to CRH (The dose of interest for CRH - 1 mkg/kg - was determined earlier, as provoking the maximal increase of plasma corticosterone level after 20 minutes of its ICV injection). Whole blood was collected at 11.00 am, via indwelling jugular catheter at 0 (control) and 15 minutes after Nadolol injection, also 30 and 60 min after CRH injection. After centrifugation the plasma level of corticosterone was essayed using ELISA method. 15 minutes after Nadolol injection the level of plasma corticosterone in comparing with control wasn't changed, at subsequent time-points plasma corticosterone level was increased but significant difference was observed only after 30 minutes. Thus, according our results, 30 min after injection, the dose of Nadolol, sufficient to prevent CRH-induced increase in heart rate, doesn't preclude the CRH-induced increase of plasma corticosterone - one of key signs of the stress-axis activation. The results were discussed.

Central but not peripheral beta-adrenergic antagonism blocks reconsolidation for a morphine place preference

Blocking the process of memory reconsolidation by means of amnestic agents may prove to have therapeutic applications. Here we used a morphine-induced conditioned place preference as an index of drug seeking. After inducing in rats a preference for a distinctive compartment paired with morphine, the memory for drug experience was reactivated by a 20-min test session and saline, the beta-antagonist propranolol, or the peripherally acting beta-antagonist nadolol were administered. Animals which received saline or nadolol upon reactivation, or propanolol without memory reactivation, maintained their preference for the drug-paired compartment 24h and seven days later. However, animals that received propranolol upon reactivation no longer displayed a morphine preference on either test, although these animals once again expressed a preference when given a morphine-primed retest at 10 days. Our results suggest that beta-blockers may have potential for attenuating the impact of cue-induced craving which is a major cause of relapse in detoxified addicts.

Testing the combination beta-blocker plus topiramate in refractory migraine

OBJECTIVE

To test treatment combining a beta-blocker plus topiramate in migraine patients previously resistant to the two medications in monotherapy.

PATIENTS AND METHODS

Those patients who had not responded to a beta-blocker and topiramate received combined treatment.

RESULTS

Fifty-eight patients (47 women, age 25-76 years) received the combined treatment. Thirty-three (57%) met criteria for chronic migraine/medication overuse headache, 18 (31%) for migraine without aura and seven (12%) with aura. Ten (17%) discontinued due to adverse events. Among the 48 patients who tolerated the combination, 36 (75%, 62% of the total series) showed response (>50% reduction in frequency), while 12 (25%) did not. The number of days with headache/month decreased from 15.1 to 6.5 (-57%). Sixteen (44% of responders) showed an excellent (>75%) response. Eighteen patients (38%) experienced a total of 26 adverse events (mild-moderate).

CONCLUSIONS

The combination of beta-blocker plus topiramate showed a benefit in around 60% of patients who had not previously responded to monotherapy. Adverse events led to discontinuation in one out of six patients. From these open results, it seems reasonable to recommend this combination, complementary in terms of mechanism of action, as a potential strategy in patients with refractory migraine.

Comparison of endoscopic variceal ligation and nadolol plus isosorbide-5-mononitrate in the prevention of first variceal bleeding in cirrhotic patients

BACKGROUND

Both drug therapy and banding ligation are widely used in the prevention of first variceal bleeding. This study compared the efficacy and safety of band ligation vs. combination of beta-blocker and nitrate for the prevention of first bleeding in patients with cirrhosis and high-risk esophageal varices.

METHODS

A total of 61 patients with cirrhosis with moderate or severe esophageal varices associated with red color signs but without history of variceal bleeding were randomized to band ligation (30 patients) or treatment with nadolol plus isosorbide-5-mononitrate (ISMN) (31 patients). In the ligation group, multiband ligator with 4 elastic bands was applied during each session. Ligation was repeated at intervals of 4 weeks until variceal obliteration was achieved. In the combination group, the dose of nadolol was sufficient to reduce the pulse rate by 25%. ISMN 1 tablet 20 mg qd or bid was administered.

RESULTS

Both groups were similar in baseline characteristics. In the ligation group, variceal obliteration was achieved in 24 patients (80%), at a mean of 3.2 +/- 0.9 ligation sessions and 11.7 +/- 3.2 elastic bands. In the combination group, the mean daily doses of nadolol and ISMN administered were 40 +/- 14 mg and 40 +/- 12 mg, respectively. During a median follow-up of approximately 23 months, 5 patients (17%) in the ligation group and 8 patients (26%) in the combination group had upper-gastrointestinal bleeding (p = 0.53). Esophageal variceal bleeding occurred in 3 patients (10%) in the ligation group and 6 (19%) in the combination group (p = 0.42). By multivariate Cox analysis, presence of ascites was the only factor predictive of variceal bleeding. Minor complications were noted in 5 patients (17%) in the ligation group and 3 (10%) in the combination group (p = 0.47). Eight patients in the ligation group and 6 in the combination group died (p = 0.49). One (3%) patient in the ligation group and 3 (10%) in the combination group died of uncontrollable variceal bleeding.

CONCLUSION

Our preliminary results suggest that endoscopic variceal ligation is similar to the combination of nadolol plus ISMN with regard to effectiveness and safety in the prevention of first variceal bleeding in patients with cirrhosis.

Cirrhotic portal hypertension: current and future medical therapy for primary and secondary prevention of variceal bleeding

Portal hypertension (PHT) is the most common complication of chronic liver disease and develops in the vast majority of patients with cirrhosis. It is characterized by an increase of the portal vein pressure, and leads to the development of gastroesophageal varices, ascites, renal dysfunction and hepatic encephalopathy. Over the years, it has become clear that a decrease in portal pressure is not only protective against the risk of variceal (re)bleeding but is also associated with a lower long-term risk of developing other complications and with an improved long-term survival. At present, non-selective b-blockers remain the medical treatment of choice for both primary and secondary prophylaxis. However, recent advances in the knowledge of the pathophysiology of cirrhotic PHT have directed future therapy towards the increased intrahepatic vascular resistance, which in part is determined by an increased hepatic vascular tone. This increased vasculogenic component provides the motivation to the use of therapies aimed at increasing intrahepatic vasorelaxing capacity on the one hand and at antagonizing excessive intrahepatic vasoconstrictor force on the other hand. This review covers current and future developments in the treatment of PHT with regard to primary and secondary prophylaxis.

Evaluation of endoscopic variceal ligation (EVL) versus propanolol plus isosorbide mononitrate/nadolol (ISMN) in the prevention of variceal rebleeding: comparison of cirrhotic and noncirrhotic patients

Both EVL and drug therapy are effective in the prevention of variceal rebleeding. Comparisons between the two modalities are few, and only in cirrhotics. This prospective randomized controlled trial compared EVL with drug therapy (propranolol + ISMN) in the prevention of rebleeds from esophageal varices in cirrhotic and noncirrhotic portal hypertension (NCPH) patients. One hundred thirty-seven variceal bleeders were randomized to EVL (Group I; n = 71) or drug therapy (Group II; n = 66). In Group I, EVL was done every 2 weeks till obliteration of varices. In Group II, propranolol (dose sufficient to reduce heart rate to 55 bpm/maximum tolerated dose) and ISMN (incremental dose up to 20 mg BD) were administered. Group I and II patients had comparable baseline characteristics, follow-up (12.4 vs. 11.1 months), cirrhotics and noncirrhotics [50(70.4%) and 21(29.6%) vs. 51(77.3%) and 15(22.7%)] and frequency of Child's A (35 vs. 27), B (26 vs. 28), and C (9 vs. 11). The mean daily dose was 109 +/- 46 mg propranolol and 34 +/- 11 mg ISMN and was comparable in cirrhotic and NCPH patients. Upper GI bleeds occurred in 10 patients in Group I (5 from esophageal varices) and in 18 patients in Group II (15 from esophageal varices) (P = 0.06). The actuarial probability of rebleeding from esophageal varices at 24 months was 22% in Group I and 37% in Group II (P = 0.02). The probability of bleed was significantly higher in Child's C compared to Child's A/B cirrhotics (P = 0.02). On subgroup analysis, in NCPH patients, the actuarial probability of bleed at 24 months was significantly lower in Group I compared to Group II (25% vs 37%; P = 0.01). In cirrhotics, there was no difference in the probability of rebleeding between patients in Group I and those in Group II (P = 0.74). In Group II, 25.7% patients had adverse effects of drug therapy and 9% patients had to stop propranolol due to serious adverse effects, none required stopping ISMN. There were 10 deaths, 6 in Group I (bleed related, 1) and 4 in Group II (bleed related, 1); the actuarial probability of survival was comparable (P = 0.39). EVL and combination therapy are equally effective in the prevention of variceal rebleeding in cirrhotic patients. EVL is more effective than drug therapy in the prevention of rebleeds in patients with NCPH and, hence, recommended. However, in view of the small number of NCPH patients, further studies are needed before this can be stated conclusively.

A placebo-controlled clinical trial of nadolol in the prophylaxis of growth of small esophageal varices in cirrhosis

BACKGROUND & AIMS

Beta-blockers are extensively used to prevent variceal bleeding in patients with large esophageal varices. It is not established if beta-blockers delay the growth of small varices.

METHODS

A total of 161 patients with cirrhosis and small esophageal varices (F1 according to the classification of Beppu et al.) without previous bleeding were enrolled. A total of 83 patients were randomized to nadolol (dose adjusted to decrease resting heart rate by 25%; mean dose given, 62 +/- 25 mg/day) and 78 to placebo. The principal end point was occurrence of large esophageal varices (F2 or F3 according to the classification of Beppu et al.). Endoscopic examination was performed after 12, 24, 36, 48, and 60 months of follow-up. Mean follow-up was 36 months.

RESULTS

The 2 groups were well matched for demographic and clinical characteristics. During the study period, 9 patients randomized to nadolol and 29 randomized to placebo had growth of esophageal varices. At the end of follow-up, the cumulative risk was 20% versus 51% (P < 0.001) (absolute risk difference, 31%; 95% confidence interval, 17%-45%). When possible confounding factors were taken into account, treatment was a significant factor predicting growth of varices (odds ratio, 4.0; 95% confidence interval, 1.95-8.4). The cumulative probability of variceal bleeding was also lower in patients randomized to nadolol (P = 0.02). Survival was not different (P = 0.33). Adverse effects resulting in withdrawal of drug occurred in 9 in the nadolol group and one in the placebo group (P = 0.01).

CONCLUSIONS

This study suggests that beta-blocker prophylaxis of variceal bleeding in patients with compensated cirrhosis should be started when small esophageal varices are present.

Central beta-adrenergic modulation of cognitive flexibility

Situational stressors and anxiety impede performance on creativity tests requiring cognitive flexibility. Preliminary research revealed better performance on a task requiring cognitive flexibility, the anagram task, after propranolol (beta-adrenergic antagonist) than after ephedrine (beta-adrenergic agonist). However, propranolol and ephedrine have both peripheral and central beta-adrenergic effects. In order to determine whether noradrenergic modulation of cognitive flexibility is a centrally or peripherally mediated phenomenon, we compared the effects of propranolol (peripheral and central beta-blocker), nadolol (peripheral beta-blocker), and placebo on anagram task performance. Solution latency scores for each subject were compared across the drug conditions. Anagram solution latency scores after propranolol were significantly lower than after nadolol. This suggests a centrally mediated modulatory influence of the noradrenergic system on cognitive flexibility.

Nadolol is superior to isosorbide mononitrate for the prevention of the first variceal bleeding in cirrhotic patients with ascites

BACKGROUND/AIMS

beta-blockers effectively prevent first variceal bleeding (FVB) in cirrhotic patients. In patients with ascites, however, their use might be precluded by a high rate of contraindications and side effects. We compared the efficacy and applicability of nadolol and isosorbide-mononitrate (IsMn) in preventing FVB in a population of cirrhotic patients at high risk of variceal bleeding with ascites, who can be frequently intolerant to beta-blockers.

METHODS

A total of 80 consecutive cirrhotic patients with ascites and esophageal varices (25% average risk of bleeding at 1 year) were considered, 28 were excluded due to contraindications and 52 were randomly assigned to receive nadolol (n=25) or IsMn (n=27).

RESULTS

Frequency of contraindications was greater for beta-blockers than IsMn (35 versus 0%, P=0.001). During 21.3+/-11.6 months of follow-up, side effects forced six patients taking nadolol and four taking IsMn to stop treatment. Bleeding occurred in two patients taking nadolol and ten taking IsMn. The probability of bleeding was significantly lower in the nadolol group (P<0.05), whereas overall survival was similar (seven patients on IsMn and eight on nadolol died, P=0.3).

CONCLUSIONS

In patients with ascites IsMn is tolerated but ineffective while nadolol is effective but less tolerated.

Chemical sympathectomy has no effect on the severity of murine AIDS: murine AIDS alone depletes norepinephrine levels in infected spleen

Numerous studies have shown that alterations in sympathetic nervous system (SNS) function produced by beta-adrenergic receptor blockade or chemical sympathectomy can produce changes in T and B lymphocyte function and both innate and acquired immune responses. However, fewer studies have investigated changes in immune response following SNS alterations in animal models of disease. We tested whether blocking SNS activity using 6-OHDA or the beta-receptor antagonist nadolol alters the typical pattern in production of T helper 1 (Th1) and Th2 cytokines seen in cultures of spleen cells from C57BL/6 mice infected with murine AIDS (MAIDS). We found that neither method of sympathetic blockade affected cytokine response to MAIDS. We also found that the norepinephrine concentration and content of the spleen were reduced dramatically by the MAIDS infection itself at 3 and 6 weeks after LP-BM5 inoculation. This finding has not been previously reported in mice with MAIDS and suggests that the viral infection itself produces a functional sympathectomy in the spleen, a target of that infection.

Endoscopic ligation compared with combined treatment with nadolol and isosorbide mononitrate to prevent recurrent variceal bleeding

BACKGROUND

After an episode of acute bleeding from esophageal varices, patients are at high risk for recurrent bleeding and death. We compared two treatments to prevent recurrent bleeding--endoscopic ligation and combined medical therapy with nadolol and isosorbide mononitrate.

METHODS

We randomly assigned 144 patients with cirrhosis who were hospitalized with esophageal variceal bleeding to receive treatment with endoscopic ligation (72 patients) or the combined medical therapy (72 patients). Sessions of ligation were repeated every two to three weeks until the varices were eradicated. The initial dose of nadolol was 80 mg orally once daily, with adjustment according to the resting heart rate; isosorbide mononitrate was given in increasing doses, beginning at 20 mg once a day at bed time and rising over the course of one week to 40 mg orally twice a day, unless side effects occurred. The primary end points were recurrent bleeding, complications, and death.

RESULTS

The median follow-up period was 21 months. A total of 35 patients in the ligation group and 24 in the medication group had recurrent bleeding. The probability of recurrence was lower in the medication group, both for all episodes related to portal hypertension (P=0.04) and for recurrent variceal bleeding (P=0.04). There were major complications in nine patients treated with ligation (seven had bleeding esophageal ulcers and two had aspiration pneumonia) and two treated with medication (both had bradycardia and dyspnea) (P=0.05). Thirty patients in the ligation group died, as did 23 patients in the medication group (P=0.52). The probability of recurrent bleeding was lower for patients with a hemodynamic response to therapy, defined as a decrease in the hepatic venous pressure gradient of more than 20 percent from the base-line value or to less than 12 mm Hg (18 percent, vs. 54 percent in patients with no hemodynamic response at one year; P<0.001), and the probability of survival was higher (94 percent vs. 78 percent at one year, P=0.02).

CONCLUSIONS

Combined therapy with nadolol and isosorbide mononitrate is more effective than endoscopic ligation for the prevention of recurrent bleeding and is associated with a lower rate of major complications. A hemodynamic response to treatment is associated with a better long-term prognosis.

Comparison of the effects of nadolol and bisoprolol on the isoprenaline-evoked dilatation of the dorsal hand vein in man

AIMS

We attempted to explore the possible differential involvement of beta-adrenoceptor subtypes in the dilator response of the human dorsal hand vein to isoprenaline by examining the ability of bisoprolol, a selective beta1-adrenoceptor antagonist, and nadolol, a nonselective beta1/beta2-adrenoceptor antagonist, to antagonize the response.

METHODS

Twelve healthy male volunteers participated in four weekly sessions. In the preliminary session a dose-response curve to the vasoconstrictor effect of phenylephrine was constructed and the dose producing 50-75% maximal response was determined for each individual. In each of the remaining three (treatment) sessions, nadolol (40 mg), bisoprolol (5 mg) or placebo was ingested, and isoprenaline hydrochloride (3.33-1000 ng min(-1)) was infused locally into the dorsal hand vein along with a constant dose of phenylephrine hydrochloride (to preconstrict the vein) 2 h after the ingestion of the drugs. Changes in vein diameter were monitored with the dorsal hand vein compliance technique. Subjects were allocated to treatment session according to a double-blind balanced cross-over design. Systolic and diastolic blood pressure, and heart rate were also measured.

RESULTS

Isoprenaline produced dose-dependent venodilatation which was antagonized by nadolol but remained unaffected by bisoprolol (ANOVA with repeated measures: P < 0.025; Dunnett's test: placebo vs nadolol, P < 0.01; placebo vs bisoprolol, P = NS). Mean log ED50 (ng min-1) was significantly increased in the presence of nadolol and remained unchanged in the presence of bisoprolol (ANOVA, P < 0.025; Dunnett's test: placebo vs nadolol, P < 0.005; placebo vs bisoprolol, P = NS; differences between mean log ED50 [95% CI]: placebo vs bisoprolol -0.11 [-0.38, 0.16], placebo vs nadolol 0.32[0.09, 0.72], bisoprolol vs nadolol -0.43 [-0.71, -0.15]). Mean Emax did not differ in the three treatment conditions.

CONCLUSIONS

The failure of bisoprolol to attenuate isoprenaline-evoked venodilatation in the human dorsal hand vein argues against the involvement of a beta1-adrenoceptor-mediated component in the isoprenaline-evoked venodilatory responses. The possibility cannot be excluded that the consequences of beta1-adrenoceptor blockade by bisoprolol might have been obscured by a possible venodilator effect of bisoprolol.

Ion-exchange fibers and drugs: an equilibrium study

The purpose of this study was to investigate the mechanisms of drug binding into and drug release from cation-exchange fibers in vitro under equilibrium conditions. Ion-exchange groups of the fibers were weakly drug binding carboxylic acid groups (-COOH), strongly drug binding sulphonic acid groups (-SO(3)H), or combinations thereof. Parameters determining the drug absorption and drug release properties of the fibers were: (i) the lipophilicity of the drug (tacrine and propranolol are lipophilic compounds, nadolol is a relatively hydrophilic molecule), (ii) the ion-exchange capacity of the fibers, which was increased by activating the cation-exchange groups with NaOH, (iii) the ionic strength of the extracting salt (NaCl), which was studied in a range of 1.5 mM to 1.5 M, and finally (iv) the effect of divalent calcium ions (CaCl(2)) on the release of the model drugs, which was tested and compared to monovalent sodium ions (NaCl), and combinations thereof. It was found that the lipophilic drugs, tacrine and propranolol, were retained in the fibers more strongly and for longer than the more hydrophilic nadolol. The more hydrophilic nadolol was released to a greater extent from the fibers containing strong ion-exchange groups (-SO(3)H), whereas the lipophilic drugs were attached more strongly to strong ion-exchange groups and released more easily from the weak (-COOH) ion-exchange groups. The salt concentration and the choice of the salt also had an effect: at lower NaCl concentrations more drug was released as a result of the influence of both electrostatic and volume effects (equimolar drug:salt ratio). Incorporation of CaCl(2) in the bathing solution increased drug release considerably as compared to NaCl alone. The equilibrium distribution of the drug species between the fiber and external solution phases was also simulated and it was found that the theoretical modelling proposed describes adequately the basic trends of the behavior of these systems.

The sixth Carlos E. Rubio Memorial Lecture. Prevention and treatment of variceal hemorrhage

The medical treatment of portal hypertension has experienced a marked progress in the past decade due to the introduction of effective portal hypotensive therapy. This has been possible because of the better understanding of the pathophysiological mechanisms leading to portal hypertension. A major step forward was the introduction of beta-blockers for the prevention of bleeding and rebleeding from gastroesophageal varices. Effective therapy requires the reduction of the hepatic venous pressure gradient (HVPG) to 12 mmHg or below, or at least by 20% of baseline values. Unfortunately, this is only achieved in 1/3 to 1/2 of patients. Combination therapy, associating isosorbide-5-mononitrate and propranolol or nadolol administration enhances the reduction in portal pressure and increases the number of patients in whom HVPG decreases by more than 20% of baseline values and below 12 mmHg. Randomized clinical trials (RCT's) do support the concept that combination therapy is more effective than propranolol or nadolol alone, significantly better than sclerotherapy, and probably than endoscopic banding ligation. Therapy may be complemented by the association of spironolactone. The main inconvenience of pharmacological therapy is that there is no non-invasive method available to detect non-responders to treatment. Failures of drug therapy should be managed endoscopically. Failures of endoscopic treatment require 'rescue' by means of TIPS or shunt surgery. Patients with advanced liver failure should be considered for orthotopic liver transplantation, and put into a waiting list if eligible. In the treatment of acute variceal bleeding pharmacological therapy offer the unique advantage of allowing to provide specific therapy immediately after arrival to hospital, or even during transferral to hospital by ambulance, since it does not require sophisticated equipment and highly qualified medical staff. Vasopressin has been abandoned because of its toxicity, although this can be reduced by the combined administration of transdermal nitroglycerin. Terlipressin has longer effects and is more effective and safer than vasopressin alone or in combination with nitroglycerin. It has proved to be effective and to decrease mortality from bleeding in double-blind studies. RCT's have shown that this drug is as effective and safer than emergency sclerotherapy. Therapy should be maintained for five days to prevent early rebleeding. Somatostatin is probably as effective as terlipressin. Octreotide is probably useful after endoscopic therapy but can not be recommended as first line treatment. Endoscopic injection sclerotherapy and endoscopic banding ligation are very effective, but require well trained medical staff. There is an increasing trend for initiating therapy with a pharmacological agent, followed by semi-emergency endoscopic therapy as soon as a well trained endoscopist is available (within 12-24 hours), while maintaining drug therapy for 5 days. Failures of medical therapy may be treated by a second session of endoscopic treatment, but if this fails TIPS of emergency surgery should be done. In high-risk situations, such as bleeding from gastric varices or in patients with advanced liver failure, the decision for TIPS or surgery should be done earlier, after failure of the initial treatment.

Effectiveness and limitations of beta-blocker therapy in congenital long-QT syndrome

BACKGROUND

beta-blockers are routinely prescribed in congenital long-QT syndrome (LQTS), but the effectiveness and limitations of beta-blockers in this disorder have not been evaluated.

METHODS AND RESULTS

The study population comprised 869 LQTS patients treated with beta-blockers. Effectiveness of beta-blockers was analyzed during matched periods before and after starting beta-blocker therapy, and by survivorship methods to determine factors associated with cardiac events while on prescribed beta-blockers. After initiation of beta-blockers, there was a significant (P<0.001) reduction in the rate of cardiac events in probands (0.97+/-1.42 to 0.31+/-0.86 events per year) and in affected family members (0. 26+/-0.84 to 0.15+/-0.69 events per year) during 5-year matched periods. On-therapy survivorship analyses revealed that patients with cardiac symptoms before beta-blockers (n=598) had a hazard ratio of 5.8 (95% CI, 3.7 to 9.1) for recurrent cardiac events (syncope, aborted cardiac arrest, or death) during beta-blocker therapy compared with asymptomatic patients; 32% of these symptomatic patients will have another cardiac event within 5 years while on prescribed beta-blockers. Patients with a history of aborted cardiac arrest before starting beta-blockers (n=113) had a hazard ratio of 12.9 (95% CI, 4.7 to 35.5) for aborted cardiac arrest or death while on prescribed beta-blockers compared with asymptomatic patients; 14% of these patients will have another arrest (aborted or fatal) within 5 years on beta-blockers.

CONCLUSIONS

beta-blockers are associated with a significant reduction in cardiac events in LQTS patients. However, syncope, aborted cardiac arrest, and LQTS-related death continue to occur while patients are on prescribed beta-blockers, particularly in those who were symptomatic before starting this therapy.

Long-term follow-up of patients with long-QT syndrome treated with beta-blockers and continuous pacing

BACKGROUND

The long-QT syndrome is associated with sudden cardiac death. Combination of beta-blocker and pacing therapy has been proposed for treatment of drug-resistant patients. The purpose of this study was to summarize our long-term experience with combined therapy in patients with long-QT syndrome.

METHODS AND RESULTS

A total of 37 patients with idiopathic long-QT syndrome were treated with combined therapy consisting of continuous cardiac pacing and maximally tolerated beta-blocker therapy and followed up for 6.3+/-4. 6 years (mean+/-SD). The group consisted of 32 female and 5 male patients with a mean age of 31.6 years. The mean paced rate was 82+/-7 bpm (range, 60 to 100 bpm). On follow-up, recurrent symptoms caused by pacemaker malfunction were documented in 3 patients. Four patients died during the follow-up period: 2 adolescents stopped beta-blocker therapy, 1 patient died suddenly while treated with combined therapy, and 1 patient died of unrelated causes. In addition, 3 patients had resuscitated cardiac arrest while on combined therapy, and 1 patient had repeated, appropriate implantable cardioverter-defibrillator discharges on follow-up.

CONCLUSIONS

Because 28 of 37 patients remain without symptoms with beta-blocker therapy and continuous pacing, combined therapy appears to provide reasonable, long-term control for this high-risk group. However, the incidence of sudden death and aborted sudden death (24% in all patients and 17% in compliant patients) strongly suggests the use of a "back-up" defibrillator, particularly in noncompliant adolescent patients. Implantable cardioverter-defibrillator therapy, however, may be associated with recurrent shocks in susceptible patients.

Effect of beta-adrenoreceptor blockade with nadolol on the duration of local anesthesia

BACKGROUND

beta-adrenoreceptor blockers, or beta-blockers, are drugs commonly prescribed for hypertension, angina and migraine headaches. In a patient taking beta-blocker medication, administration of a local anesthetic containing a vasoconstrictor could result in an adverse interaction.

METHODS

The authors conducted a double-blind, randomized, crossover, placebo-controlled study to test the hypothesis that a nonselective beta-blocker--nadolol--enhances vasoconstriction induced by the epinephrine contained in local anesthetic, thus resulting in an increased duration of anesthesia. Ten healthy male volunteers were given either a placebo or a single, standard oral dose of nadolol (80 milligrams). The upper lateral incisor teeth were anesthetized using lidocaine with or without epinephrine.

RESULTS

The mean duration of pulpal and soft-tissue anesthesia was increased in subjects who took nadolol compared with those who took placebo by 17 minutes (58 percent) and 16.5 minutes (19 percent), respectively, when they received 1 milliliter of lidocaine containing 1:100,000 epinephrine. These differences were both clinically and statistically significant (P = .007). Using lidocaine without epinephrine produced no clinically or statistically significant difference in duration of pulpal or soft-tissue anesthesia in the two groups of subjects. The authors noted no significant changes in blood pressure or pulse rate.

CONCLUSIONS

Administration of local anesthetic containing epinephrine to subjects receiving a beta-blocker increased the duration of pulpal and soft-tissue anesthesia. There was no difference in duration of anesthesia between groups when local anesthetic without epinephrine was used.

CLINICAL IMPLICATIONS

Use of local anesthetic containing a vasoconstrictor should be avoided in patients taking beta-blocker medication because of a possible adverse drug interaction. However, when a vasoconstrictor is indicated for hemostasis, the local anesthetic should be administered slowly and in small amounts as pulse rate and blood pressure are being monitored. The patient should be informed that the duration of anesthesia might be prolonged.

Inotropic and sympathetic responses to the intracoronary infusion of a beta2-receptor agonist: a human in vivo study

BACKGROUND

On the basis of the presence of beta2-receptors within the sympathetic nervous system, beta2-stimulation may increase cardiac sympathetic outflow. We addressed the hypothesis that sympathoexcitatory beta2-receptors are present in the human left ventricle.

METHODS AND RESULTS

The beta2-agonist salbutamol was infused into the left coronary artery in 3 groups of patients: group 1 (n=9, no beta-blocker therapy), group 2 (n=7, beta1-selective blockade with atenolol), and group 3 (n=6, nonselective beta-blockade with nadolol). Left ventricular +dP/dt in response to increasing concentrations of salbutamol was measured in all groups, and cardiac norepinephrine spillover was measured in group 1. There were no systemic hemodynamic changes in any group. Salbutamol resulted in a 44+/-6% increase in +dP/dt in group 1, a 25+/-6% increase in group 2 (P<0.05 versus group 1), and no increase in group 3. Salbutamol also resulted in a 124+/-37% increase in cardiac norepinephrine spillover in group 1 (P<0.05).

CONCLUSIONS

Evidence that salbutamol increased norepinephrine release from cardiac sympathetic nerves was provided by the observations that atenolol suppressed the salbutamol inotropic response, demonstrating that this response was mediated in part by beta1-receptors and that salbutamol also resulted in an increase in cardiac norepinephrine spillover. This result provides in vivo evidence, in humans, for the role of sympathoexcitatory cardiac beta2-receptors.

The autonomic nervous control of heart rate in ducks during voluntary diving

Autonomic nervous control of heart rate was studied in voluntarily diving ducks (Aythya affinis). Ducks were injected with the muscarinic blocker atropine, the beta-adrenergic blocker nadolol, the beta-adrenergic agonist isoproterenol, and a combination of both atropine and nadolol. Saline injection was used as a control treatment. The reduction in heart rate (from the predive level) normally seen during a dive was abolished by atropine. Nadolol reduced heart rate during all phases of diving activity-predive, dive, and postdive-indicating that sympathetic output to the heart was not withdrawn during diving. Isoproterenol increased heart rate before, during, and after the dive, although the proportional increase in heart rate was not as high during the dive as compared with the increase in routine heart rate or heart rate during the predive or postdive phase. The parasympathetic system predominates in the control of heart rate during diving despite the maintenance of efferent sympathetic influences to the heart, perhaps due to accentuated antagonism between the two branches of the autonomic nervous system.

[Verapamil-responsive ventricular tachycardia in small children: a case report and review of the literature]

A case of verapamil-responsive incessant ventricular tachycardia in a 4-year-old girl is reported. Oral verapamil alone failed in maintaining stable sinus rhythm. With association of oral verapamil and betablockers (nadolol) the patient remained asymptomatic without recurrence of ventricular tachycardia over a follow-up of 1 year. In case of failure of monotherapy with verapamil or betablockers alone, an association of both can be effective and safe also in pediatric age. Radiofrequency catheter ablation should be reserved, especially in pediatric age, only to patients with impaired ventricular function who are not responsive to medical therapy.

In vivo beta-adrenergic stimulation suppresses natural killer activity and compromises resistance to tumor metastasis in rats

The sympathetic nervous system has been implicated in mediating stress-induced alterations in NK cell activity, particularly through stimulation of beta-adrenergic receptors. However, because catecholamines induce time-dependent alterations in the distribution of NK cells, the impact of beta-adrenergic stimulation on individual NK cell cytotoxicity is not clear, nor are its implications regarding host resistance to metastatic spread. To address these issues, we used the beta-adrenergic agonist, metaproterenol (MP), in F344 rats. The number of blood NK cells doubled within 10 min of MP administration and returned to baseline levels within 1 h. By this time, MP suppressed blood NK activity in a dose-dependent manner. Two beta-adrenergic antagonists, propranolol, which crosses the blood-brain barrier, and nadolol, which does not, blocked this suppression. Corresponding findings were obtained using an NK-sensitive tumor model, the MADB106. MP caused an up to 10 times increase in the number of tumor cells retained in the lungs 1 day after inoculation and a similar rise in the number of consequent lung metastases detected 3 wk later. These effects were dose dependent and nadolol reversible. NK cells appear to play a central role in mediating the tumor-enhancing effects of MP because their selective depletion nearly abolished this effect. Overall, our findings suggest that independent of the transitory increase in numbers of blood NK cells, in vivo beta-adrenergic stimulation suppresses NK activity in the rat. This suppression is induced peripherally and can compromise host resistance to NK-sensitive tumors. Homologies to studies in humans and clinical relevance are discussed.

Prolonged treatment with beta-adrenoceptor antagonists counteracts the aggression deficit induced by chronic stress

Chronic stress-induced behavioral disturbances have been used as experimental models of depression. One of them is the deficit of fighting behavior induced by 16-day application of various unpredictable stressors. In the present study we investigated the effect of beta-adrenoceptor antagonists (propranolol, pindolol, nadolol and acebutolol) on electric footshock-induced fighting behavior in chronically stressed (14 various stressors over 16 days) male Wistar rats. It was found that the number of fighting attacks was reduced by about 50-80% in the rats submitted to chronic stress. Prolonged, 14-day, but not acute, treatment with propranolol, pindolol or nadolol (but not acebutolol) counteracted the deficit of aggression induced by chronic stress. It is suggested that beta-adrenoceptor antagonists which penetrate the blood-brain barrier may prevent the behavioral changes induced by chronic stress.

[The effects of chronic beta-blocker administration on respiratory sinus arrhythmia]

The results of studies on the effect of beta-adrenergic blockade on respiratory sinus arrhythmia (RSA) are discordant. In some studies in which an increased RSA was reported, central vagotonic activity has been proposed. The aim of this study was to verify whether chronic beta-adrenergic blockade is capable of increasing RSA, and therefore vagal outflow, and to analyze whether the mechanism of action is central or peripheral. Twenty normal subjects (mean age 28 +/- 2 years) were randomized to receive a hydrophilic (nadolol, N), a lipophilic (metoprolol, M) beta-blocker and placebo (PL). After 1 week of therapy a spectral analysis was made of the variability in heart rate and systolic blood pressure (SBP) while they controlled their breathing at 16 breaths/min for a period of 5 min. The high frequency component was calculated for the RR interval (HF-RR, RSA measure) and SBP (HF-SBP), and the squared coherence (K2) and phase functions (phi HF) were assessed between RR and SBP fluctuations in the respiratory band (RR-SBP); a negative phi HF means that RR changes follow SBP changes. The alpha HF (an index of the baroreflex gain) was also calculated. Both beta-blockers increased the mean RR interval (PL 808 +/- 21, N 1054 +/- 30, M 1031 +/- 27 ms; p < 0.0001), HF-RR (PL 6.3 +/- 0.3, N 7.1 +/- 0.3, M 7.2 +/- 0.3 ln-ms2; p = 0.002) and alpha HF (PL 13.6 +/- 1.5, N 21.9 +/- 2.8, M 24.5 +/- 3.6 ms/mmHg; p < 0.002), and both modified phi HF (PL -0.23 +/- 0.05, N -0.02 +/- 0.05, M -0.03 +/- 0.04 s; p < 0.0001). No difference was found between N and M. Chronic beta-adrenergic blockade enhanced RSA and baroreflex gain and reduced the phase between the RR interval and SBP oscillations. Since no difference was found between the hydrophilic and the lipophilic beta-blockers, these changes seem to be due to a peripheral effect.

Randomised trial of nadolol alone or with isosorbide mononitrate for primary prophylaxis of variceal bleeding in cirrhosis. Gruppo-Triveneto per L'ipertensione portale (GTIP)

BACKGROUND

The risk of having a first cirrhosis-associated variceal bleed is lowered by about 50% by beta-blockers. Use of beta-blockers is currently recommended for patients with cirrhosis and oesophageal varices that are at risk of bleeding. We aimed to test the effectiveness of isosorbide mononitrate as an adjunct to the beta-blocker nadolol in the prophylaxis of first variceal bleeding in these patients.

METHODS

We did a randomised multicentre study to compare the non-selective beta-blocker, nadolol, with nadolol plus isosorbide mononitrate in 146 relatively well (Child-Pugh score < or = 11) patients who had oesophageal varices at risk of bleeding. Patients on nadolol alone received a single oral 40 mg daily dose. Every second day the dose was titrated to achieve 20-25% decrease in resting heart rate (maximum dose 160 mg daily). Patients receiving both drugs received nadolol as above then isosorbide mononitrate was added starting with 10 mg orally twice daily, which was increased to 20 mg unless hypotension or severe headache occurred. The main endpoint was the occurrence of variceal bleeding of any severity. Patients were followed up for up to 40 months.

FINDINGS

During the study period 11 of 74 patients from the nadolol alone group and four of 72 from the nadolol plus isosorbide mononitrate group had variceal bleeding (log-rank test p = 0.03). Cumulative risk of variceal bleeding was 18% in the nadolol group and 7.5% in the combined treatment group (95% CI for difference 1-25%). Two patients in each group had a non-variceal bleed related to portal hypertension. 14 patients from the nadolol only group and eight from the combined treatment group died during the study period (log-rank test p = 0.09). Four and eight patients, respectively, had to discontinue one of the drugs because of side-effects.

INTERPRETATION

Nadolol plus isosorbide mononitrate is significantly more effective than nadolol alone in the primary prophylaxis of variceal bleeding in relatively well patients with cirrhosis, and has few side-effects.

Sleep suppression of ventricular arrhythmias: a predictor of beta-blocker efficacy

It has been reported that the frequency of premature ventricular contractions in some patients tend to decrease during the hours of sleep when modifications in autonomic tone and bradycardia occur. The aim of this study was to evaluate whether the phenomenon of sleep suppression may be a sensitive and specific parameter for predicting the antiarrhythmic effect of beta-blockers on premature ventricular contractions. The presence of sleep suppression was evaluated in 45 patients (mean age 50 +/- 17 years) with frequent premature ventricular contractions at two baseline Holter recordings. Sleep suppression was defined as > 50% reduction in the number of nighttime as opposed to day-time premature ventricular contractions. Three groups of patients were identified: those with sleep suppression at both Holter recordings (group 1); those with sleep suppression at only one Holter recording (group 2); and those without sleep suppression at either Holter recording (group 3). A third Holter was performed 5 days after nadolol administration. In group 1, nadolol led to a mean reduction in the number of premature ventricular contractions of 90% (> 70% in 21/23 patients). In group 2, the mean reduction was 76% (> 70% in three out of six patients). In group 3, there was a mean increase in the number of premature ventricular contractions of 33%. The positive predictive accuracy of sleep suppression in relation to the antiarrhythmic efficacy of nadolol is very high (88%) when sleep suppression is present during two baseline Holter recordings. Sleep suppression is a sensitive parameter for identifying the premature ventricular contractions likely to benefit from beta-blocker administration.

Beta-adrenoceptor antagonists suppress elevation in body temperature and increase in plasma IL-6 in rats exposed to open field

The purpose of these studies was to assess the involvement of beta-adrenoceptors in the development of psychological stress-induced elevation in body temperature (Tb) and rise in circulating interleukin-6 (IL-6). We selected three drugs to attempt to block the rise in body temperature and plasma IL-6; L-propranolol, D-propranolol and nadolol. Both stereoisomers of propranolol have "local anesthetic' membrane-stabilizing activity and are capable of penetrating into the brain. However, D-propranolol has significantly lower beta-blocking activity than L-propranolol. Nadolol has beta-blocking activity similar to L-propranolol without membrane-stabilizing activity. Furthermore, nadolol does not cross the blood-brain barrier. All beta-blockers were injected intraperitoneally (i.p. 7.5 mg/kg) or into the third cerebral ventricle (i.c.v., 5 or 50 micrograms/animal), 20 min or just before exposure of rats to an open field, respectively. Blood samples for measurement of plasma IL-6 activity (IL-6-dependent B9 cell bioassay) were taken from rats immediately following exposure to the open field. After exposure to the open field, rats not treated with beta-blockers responded with a rapid rise in Tb measured by biotelemetry as well as with an increase in plasma IL-6 activity. The increase in Tb of open field-exposed rats was significantly suppressed by L-propranolol injected i.p. (delta Tmax = 0.14 +/- 0.15 degrees C for L-propranolol vs. 0.78 +/- 0.15 degrees C for vehicle-treated rats). Neither i.p. injection of D-propranolol nor nadolol had any effect on the increase in Tb induced by exposure to the open field. Both i.c.v. doses of L-propranolol and nadolol markedly attenuated the open field-induced rise in Tb. The large i.c.v. dose of D-propranolol (50 micrograms) did, whereas the lower dose (5 micrograms) did not suppress the elevation in Tb in open field exposed rats. The open field-exposed rats injected with L-propranolol (both i.p. or i.c.v.) had lower plasma IL-6 activity than that of open field-exposed rats injected with vehicle (for i.p. injection: 5.2 +/- 1.3 U/ml for L-propranolol vs. 17.4 +/- 3.8 U/ml for vehicle; for i.c.v. injection: 3.5 +/- 2.3 U/ml for L-propranolol vs. 24.4 +/- 7.2 U/ml for vehicle). Nadolol blocked the open field-induced rise in plasma IL-6 only when injected i.c.v. but no i.p. Neither i.p. nor i.c.v. D-propranolol injection had an effect on plasma IL-6 activity in open field-exposed rats. These data show that beta-adrenoceptors in the central nervous system are involved in the psychological stress-induced elevation in Tb and rise in plasma IL-6 activity caused by exposure to an open field.

Duplex Doppler ultrasonography allows a multiorgan noninvasive approach to splanchnic pharmacodynamics in patients with cirrhosis

Duplex Doppler ultrasonography (DDU) is a suitable method to evaluate acute splanchnic hemodynamic effects of vasoactive drugs. It allows the contemporary evaluation of arterial and venous splanchnic parameters. Forty-six cirrhotic patients with esophageal varices were investigated by DDU. Portal blood flow mean velocity (PBV) (cm/s), portal blood flow volume (PBF) (ml/min), pulsatility index (PI) [(maximum-minimum)/mean velocity] in the superior mesenteric artery, in intrahepatic arteries (main branches), in an instrasplenic artery, and in interlobar arteries of the kidneys were measured before and 120-180 min after the administration of nadolol (80 mg p.o.) in 24 patients, and before and 120 min after placebo administration in 9 patients. In 13 patients who were chronically treated with nadolol, DDU parameters were evaluated before and 90 min after the administration of isosorbide-5-mononitrate (20 mg p.o.).

RESULTS

placebo caused no hemodynamic change. After nadolol, heart rate decreased (-22 +/- 8%), and so did PBV and PBF (8.8 +/- 3.4 vs. 10.9 +/- 3.2, -20 +/- 17%, p < 0.0001; 660 +/- 347 vs. 852 +/- 371, -24 +/- 18%, p < 0.0001). Mesenteric PI increased (2.72 +/- 0.67 vs. 2.28 +/- 0.56, +21 +/- 25%, p = 0.005). Hepatic, splenic, and renal PIs showed slight, not significant changes (1.42 +/- 0.41 vs. 1.38 +/- 0.32, p = NS; 1.05 +/- 0.23 vs. 0.99 +/- 0.21, p = NS; 1.24 +/- 0.26 vs. 1.19 +/- 0.20, p = NS, respectively). After the administration of isosorbide-5-mononitrate, PBV decreased (8.2 +/- 2.0 vs. 9.4 +/- 2.3, -12 +/- 13%, p = 0.006), while PBF did not modify (648 +/- 189 vs. 711 +/- 209, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Duplex Doppler sonographic evaluation of splanchnic and renal effects of single agent and combined therapy with nadolol and isosorbide-5-mononitrate in cirrhotic patients

Thirty-eight cirrhotic patients with esophageal varices were investigated by duplex Doppler sonography. In every patient, the portal blood flow mean velocity (cm/sec) and portal blood flow volume (ml/min) were measured. In addition, the pulsatility index [(maximum-minimum)/mean velocity] was measured in the superior mesenteric artery, in the hepatic arteries, in an intrasplenic artery, and in intrarenal arteries. These parameters were measured again 120 to 180 minutes after administration of nadolol (80 mg orally) in 22 patients, 90 minutes after administration of isosorbide-5-mononitrate (20 mg orally) in nine patients, and subsequently after administration of isosorbide 5-mononitrate to 10 of the 22 patients treated earlier with nadolol. Duplex Doppler sonographic parameters also were evaluated in seven patients 120 minutes after administration of a placebo. In five of the 22 patients treated acutely with nadolol, the same parameters were measured again after 60 minutes without any additional drug administration. No hemodynamic changes occurred in response to the placebo. Portal blood flow mean velocity and portal blood flow volume decreased after nadolol and isosorbide-5-mononitrate; mesenteric pulsatility index increased after both nadolol and isosorbide-5-mononitrate. After combined therapy, we observed a further reduction in portal blood flow mean velocity and portal blood flow volume and a significant increase in hepatic, splenic, and mesenteric pulsatility indices. The addition of isosorbide-5-mononitrate to nadolol caused a decrease in portal blood flow mean velocity of more than 17% in all patients. Nadolol caused a slight increase in renal pulsatility index, which was amplified by the addition of isosorbide-5-mononitrate, suggesting a decrease in renal blood flow.

The effects of lower than conventional doses of oral nadolol on relative beta 1/beta 2-adrenoceptor blockade

1. The aim of the present study was to evaluate the relative beta 1/beta 2 antagonist selectivity of the beta-adrenoceptor blocker nadolol, in lower than conventional clinical doses. 2. Eight normal volunteers received single oral doses of either placebo (PL), nadolol 5 mg (N5), 20 mg (N20) or 80 mg (N80) in a single-blind, randomised crossover design. beta 1-adrenoceptor antagonism was assessed by attenuation of exercise tachycardia, and beta 2-adrenoceptor blockade by effects on salbutamol-induced chronotropic, hypokalaemic and finger tremor responses. The relative percentage attenuation of beta 2 and beta 1-mediated responses was calculated and expressed as beta 2:beta 1 selectivity ratios. 3. Nadolol produced dose-related reductions in exercise tachycardia in keeping with increasing beta 1-adrenoceptor blockade; mean % reduction (95% CI) compared with placebo: N5 10.7 (6.6 to 14.8), N20 21.4 (17.3 to 25.4), N80 38.9 (34.8 to 42.9). However, even the lowest dose of nadolol (5 mg) produced almost complete blunting of beta 2-mediated effects and significantly increase exercise hyperkalaemia; peak exercise hyperkalaemia (mmol l-1) (means and 95% CI): PL 4.88 (4.68 to 5.07), N5 5.36 (5.17 to 5.55), N20 5.48 (5.28 to 5.67), N80 5.42 (5.22 to 5.61). beta 2:beta 1 selectivity ratios significantly increased as the dose of nadolol was reduced. 4. These data suggest that whereas in the clinical dose range nadolol behaves as a non-selective beta-adrenoceptor antagonist, as the dose is reduced this drug demonstrates an increasing degree of selectivity for the beta 2-adrenoceptor.(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian and power spectral changes of RR and QT intervals during treatment of patients with angina pectoris with nadolol providing evidence for differential autonomic modulation of heart rate and ventricular repolarization

This study evaluates the effects of autonomic manipulation by chronic beta blockade with nadolol on the circadian and power spectral changes of heart rate and QT interval. It was hypothesized that differential innervation of the atria and ventricles by sympathetic and parasympathetic fibers may produce differential effects on heart rate and QT interval variabilities. Holter recordings of 12 male patients (age 63 +/- 7 years) with stable angina were analyzed before and after 3 weeks of nadolol therapy. The QT intervals were individually normalized by an exponential formula to study the circadian variation of QTc. Power spectra of RR and uncorrected QT intervals were obtained by fast-Fourier analysis from 256 consecutive sinus beats during the day at maximal heart rate and during the night at minimal heart rate. Frequency-specific variability was determined from areas under the spectral plots. Both heart rate and QTc exhibited significant circadian patterns (p < 0.01) in opposite phase with each other. Mean heart rate was significantly reduced with nadolol (81 +/- 12 vs 67 +/- 12 beats/min, p < 0.001), with greater reduction during daytime. The mean QTc was unexpectedly reduced after nadolol treatment, with borderline significance (p = 0.06). The RR variability in the frequency range of 0.05 to 0.25 Hz was significantly increased with nadolol at 3:00 A.M. (p < 0.01) but not at 1:00 P.M. The QT variability in the same frequency range of was not significantly increased with nadolol. The power spectra of RR and QT intervals were dissimilar except at the lower frequencies around 0.05 Hz.(ABSTRACT TRUNCATED AT 250 WORDS)

Usefulness of amlodipine for angina pectoris

Calcium antagonists are effective antianginal agents in the treatment of patients with stable exercise-induced angina pectoris. A series of randomized, double-blind, placebo-controlled studies with the novel, once-daily calcium antagonist amlodipine have been completed in a large number of patients with stable exercise-induced angina pectoris. Compared with placebo, once-daily amlodipine demonstrated a significant dose-related extension in exercise duration and workload accomplished, and reduction in number of anginal attacks and associated glyceryl trinitrate consumption. The clinical antianginal attributes of amlodipine were accompanied by significant reductions in electrocardiographic evidence of myocardial ischemia. In comparison with other antianginal drugs, once-daily amlodipine at a dosage range of 5-10 mg demonstrated antianginal activity comparable to thrice-daily diltiazem and once-daily nadolol. Amlodipine administered once daily achieves symptomatic and electrocardiographic amelioration of myocardial ischemic episodes induced by exercise in the majority of patients with stable angina pectoris. Amlodipine does not depress left ventricular pumping activity, and its side-effect profile does not differ substantially from that of placebo.

[The pharmacokinetics and pharmacodynamics of the prolonged-action beta-adrenoblocker nadolol at rest after a single administration to hypertension patients]

The pharmacokinetics and pharmacodynamics of nadolol given in a single dose of 80 mg to 17 patients with mild hypertension were studied by echocardiography at rest. The major pharmacokinetic parameters for nadolol did not differ greatly from those reported in the literature and obtained from volunteers. No correlation was found between endogenous creatine clearance and renal nadolol clearance. How the hemodynamic effect developed and whether it was related to blood nadolol concentrations in time after single administration were followed up and discussed. There was a significant decline in blood pressure 2 hours after the drug. There was a clock-wise hysteresis in the relationship between the changes in cardiac output and nadolol levels. Changes in blood pressure were shown to significantly correlate with those in cardiac output.

Enalapril versus combined enalapril and nadolol treatment: effects on blood pressure, heart rate, humoral variables, and plasma potassium at rest and during exercise in hypertensive patients

The effect of enalapril alone and in combination with nadolol on resting and exercising blood pressure, heart rate, plasma renin activity, aldosterone, noradrenaline, and potassium levels was studied in 10 hypertensive patients (diastolic blood pressure between 95 and 114 mmHg). Patients received placebo for 4 weeks, enalapril (mean daily dose 24.5 mg) for 8 weeks, and nadolol, 40 mg once daily, was added for the remaining 8 weeks of the study. Exercise testing (modified Bruce, treadmill) was conducted at the end of the placebo run-in phase and at the end of each treatment period. Enalapril reduced resting and exercising blood pressure independent of any change in heart rate: This effect was increased with combination treatment. Plasma renin activity at rest and during exercise was increased by enalapril. Combination treatment attenuated this response and significantly reduced plasma aldosterone. Neither treatment had any effect on plasma noradrenaline levels. Resting plasma potassium levels were increased with combination treatment, whereas both treatment regimens increased plasma potassium levels during exercise. There were no clinically relevant episodes of hyperkalemia. Further investigation is required to qualify the nature of the blood pressure and plasma potassium response with combination treatment.

[The pharmacokinetics of the prolonged-action beta-adrenoblocker nadolol in hypertension patients after a single administration]

The pharmacokinetics of the beta-adrenoceptor blocker nadolol was studied in 30 patients suffering from mild hypertension given a single 80 mg dose of the drug. It has been shown that distribution of the pharmacokinetic parameters in this sample can be assumed normal. Their averages are similar to the reported data on healthy subjects. The mean retention time of nadolol in the body was estimated for the first time. The absorption of the drug was shown to be slow, which together with a low degree of bioavailability, may be associated with its low lipophility. A close correlation was demonstrated between the half-life and the mean absorption time estimates computed from blood serum and nadolol excretion with urine. The conclusion is made that glomerular filtration plays the key role in the drug elimination.

Efficacy and safety of intravenous and oral nadolol for supraventricular tachycardia in children

The efficacy and safety of oral nadolol in supraventricular tachycardia were evaluated prospectively in 27 children (median age 5.5 years). Fifteen patients had an unsuccessful trial of digoxin therapy. Intravenous nadolol was given to seven patients during electrophysiologic study; five of these had an excellent response and two had a partial response (25% decrease in tachycardia rate). Six of these patients had a similar response to oral nadolol. Twelve patients received both propranolol and nadolol. Among six patients, intravenous propranolol was successful in four and unsuccessful in two; all six had a similar response to oral nadolol. With oral propranolol, tachycardia was well controlled in four patients and persistent in two; five of five patients had a similar response to oral nadolol. Twenty-six patients were treated with oral nadolol; the arrhythmia was well controlled in 23, 2 had recurrent tachycardia and 1 patient had tachycardia at a 25% slower rate. The effective dose of nadolol ranged between 0.5 and 2.5 mg/kg body weight once daily (median dose 1 mg/kg per day). During follow-up (3 to 36 months), compliance and tolerance were excellent; excluding 2 patients with reactive airway disease who developed wheezing, only 3 (12%) of 24 had side effects necessitating a change in drug therapy. Once a day nadolol is a safe and effective agent in the management of supraventricular tachycardia in children. Its long-term efficacy can be predicted by the short-term response to intravenous nadolol or propranolol during programmed electrophysiologic study.

[Effect of long-term treatment with prazosin and its combination with nadolol on the levels of blood hormones of the hypophyseal- gonadal system in patients with hypertension]

The levels of pituitary and gonadal hormones were measured by radioimmunoassay during a long-term (12-month) therapy with prazosin and its combination in 23 patients aged 30-59 years who suffered from Stage II hypertensive disease. Prazosin monotherapy resulted in a significant decrease in prolactin levels, followed by inhibited elaboration of luteinizing, follicle-stimulating, and testicular hormones in the first 6 months of therapy without changing estradiol levels. The hypoprolactinemic effect of prazosin was significantly enhanced with an increase in therapy duration and more profound in patients who had high baseline prolactin levels and in younger patients. Prazosin in combination with nadolol was found to level off the hyperprolactinemic effect of the latter without potentiating the reduction in the levels of follicle-stimulating, luteinizing, and testicular hormones which was observed during therapy with each drug alone.