Expression of the Wnt inhibitor Dickkopf-1 is required for the induction of neural markers in mouse embryonic stem cells differentiating in response to retinoic acid

Cultured mouse D3 embryonic stem (ES) cells differentiating into embryoid bodies (EBs) expressed several Wnt isoforms, nearly all isotypes of the Wnt receptor Frizzled and the Wnt/Dickkopf (Dkk) co-receptor low-density lipoprotein receptor-related protein (LRP) type 5. A 4-day treatment with retinoic acid (RA), which promoted neural differentiation of EBs, substantially increased the expression of the Wnt antagonist Dkk-1, and induced the synthesis of the Wnt/Dkk-1 co-receptor LRP6. Recombinant Dkk-1 applied to EBs behaved like RA in inducing the expression of the neural markers nestin and distal-less homeobox gene (Dlx-2). Recombinant Dkk-1 was able to inhibit the Wnt pathway, as shown by a reduction in nuclear beta-catenin levels. Remarkably, the antisense- or small interfering RNA-induced knockdown of Dkk-1 largely reduced the expression of Dlx-2, and the neuronal marker beta-III tubulin in EBs exposed to RA. These data suggest that induction of Dkk-1 and the ensuing inhibition of the canonical Wnt pathway is required for neural differentiation of ES cells.

Eccentric atherosclerotic plaques with positive remodelling have a pericardial distribution: a permissive role of epicardial fat? A three-dimensional intravascular ultrasound study of left anterior descending artery lesions

AIMS

The transversal distribution of coronary atherosclerotic plaques (AP) (myocardial vs pericardial) affects vessel remodelling. The aim of this study was to define the impact of transversal lesion distribution on vessel remodelling in proximal and distal coronary segments using a 3D intravascular ultrasound (IVUS) reconstruction.

METHODS

The study group included 70 lesions located in the left anterior descending artery within 5mm of the septal take-off, and imaged using 3D-IVUS. The take-off of the septal branch was used to divide the plaque into a myocardial and pericardial surface. The IVUS index of vessel remodelling was calculated as: [narrowest external elastic membrane (EEM) site cross-sectional area (CSA)-reference EEM CSA)/reference EEM CSAx100]. The lesions with an intermediate vessel remodelling index (between -25% and +15%) were excluded from analysis.

RESULTS

Of the 38 APs with a pericardial distribution, 34 (89%) showed positive remodelling (P<0.001). The distal lesions had a positive vessel remodelling index regardless of transversal plaque distribution. At multivariate analysis, pericardial distribution and the distal location of AP were the only independent variables predictive of positive remodelling.

CONCLUSIONS

The transversal distribution of atherosclerotic plaque affects vessel remodelling in left anterior descending coronary lesions, probably because of an extravascular splinting effect. Distal lesions usually show positive remodelling regardless of transversal plaque distribution.

An Italian chart for cardiovascular risk prediction. Its scientific basis

A risk chart for primary prediction of major coronary and cerebrovascular events based on Italian population data was created. Material from three Italian population studies was available: the Italian Rural Areas of the Seven Countries Study (no. 1712), the Gubbio Study (no. 3061) and the ECCIS Study (no. 4998) for a total of 9771 men and women aged 35 to 74 years and followed-up from 5 to 15 years, for a total of over 55,000 person/years. Sex, age, diabetes, cigarette smoking, systolic blood pressure and serum cholesterol were selected as risk factors, while the endpoint was established as the occurrence of the first major coronary or cerebrovascular event in 10 years. The accelerated failure time model was used as the predictive model. Two models were adopted, i.e., for relatively younger subjects (45-59 years) and for relatively older subjects (60-74 years). Both produced highly significant coefficients for each of the selected risk factors. The two models carried a satisfactory discriminating power, with 40% to more than 50% of all events located in the upper quintile of the estimated risk. Sex, age (6 classes), diabetes, cigarette smoking (4 classes), systolic blood pressure (4 classes) and serum cholesterol (5 classes) were considered for the creation of a risk map derived from multivariate models. A total of 1920 cells were filled with different colors corresponding to 6 classes of absolute risk. A similar set of cells was filled with another color scale for the estimate of the relative risk versus subjects of the same age and sex carrying Italian mean levels of risk factors. The chart is being distributed to the Italian medical profession as a practical tool to select high-risk individuals for the primary prevention of major cardiovascular diseases.

Angiotensin-converting enzyme inhibitors and kidney protection: the AIPRI trial. The ACE Inhibition in Progressive Renal Insufficiency (AIPRI) Study Group

A protective effect of angiotensin-converting enzyme (ACE) inhibitors has been shown in patients with diabetic nephropathy but has not been clearly established in nondiabetic renal disease. A multicenter European study was designed to determine whether the ACE inhibitor benazepril was safe and effective in protecting residual renal function in patients with various renal diseases and mild to moderate renal failure. The trial involved 583 patients from 49 centers in Italy, France, and Germany. The patients were randomized to receive benazepril or placebo plus other antihypertensive agents, the target being a diastolic blood pressure of less than 90 mm Hg. Thirty-one patients in the benazepril group and 57 patients in the placebo group reached the end point [the time elapsed from entry to (a) doubling of serum creatinine (SCr) concentrations and (b) start of renal replacement therapy; p < 0.001 at 3 years]. The associated reduction in the relative risk of reaching the end point was 53% in benazepril-treated patients, with actuarial renal survival probability significantly better at 3 years. The best survival of renal function was observed in patients with chronic glomerular diseases and proteinuria greater than 1.0 g/24 h. Benazepril is effective in slowing the rate of progression and improving the survival of renal function in patients with renal diseases of various origins. This protective effect is associated with a clinically relevant decrease in both blood pressure and proteinuria.

Benazepril causes in hypertension a greater reduction in left ventricular mass than does nitrendipine: a randomized study using magnetic resonance imaging

To assess the comparative effects of benazepril and nitrendipine monotherapies on left ventricular mass index (LVMI) in hypertensive patients with echocardiographically determined left ventricular hypertrophy, patients with diastolic blood pressure (BP) > or = 100 mm Hg were randomized to benazepril, 10 mg, or nitrendipine, 20 mg, both given once or twice daily. After 4 weeks, only the responders (diastolic BP <90 mm Hg) entered a 5-month maintenance period. At baseline, and after 3 and 6 months, LVMI was blindly estimated by means of magnetic resonance imaging (MRI) and, for comparison, by means of echocardiography. Of the 50 randomized patients, three were excluded from the study as nonresponders after 4 weeks; moreover, two patients taking benazepril and one taking nitrendipine discontinued the treatment after 2 months for adverse effects. Both monotherapies reduced systolic and diastolic BP to a similar extent. After 3 months, MRI-estimated LVMI decreased by 21.5 g/m2 in the benazepril and 8.8 g/m2 in the nitrendipine group, with an adjusted mean difference between the two groups of 11.1 g/m2 (95% CI, 7.3-14.8 g/m2; p = 0.0001). After 6 months, it decreased by 23.6 g/m2 and 10.0 g/m2, respectively, with an adjusted mean difference of 11.3 g/m2 (95% CI, 7.5-15.5; p = 0.0001) in favor of benazepril. In conclusion, despite a similar antihypertensive effect, benazepril led to a greater reduction in MRI-measured LVMI than did nitrendipine (-16.2% vs. -7.2%) in hypertensive patients with left ventricular hypertrophy.

Long-term progression of chronic renal insufficiency in the AIPRI Extension Study. The Angiotensin-Converting-Enzyme Inhibition in Progressive Renal Insufficiency Study Group

The Angiotensin-converting-enzyme Inhibition on Progressive Renal Insufficiency (AIPRI) Study showed that the ACE inhibitor benazepril provides protection against loss of renal function in patients with chronic renal insufficiency (CRI) caused by various renal diseases. As a result of unexpectedly low mortality in the placebo group, there was a substantial imbalance in mortality during the course of this study (8 patients on benazepril vs. 1 on placebo). The aim of the extension study was to follow-up the patients from the AIPRI core study until autumn 1996, focusing on CRI progression and mortality. Data collection was post hoc. Patients were treated according to investigators' usual practices, without knowledge of the core study trial medication or (initially) the core trial results. A new primary efficacy parameter was defined as the time from the start of core study treatment to the occurrence of the first event in the combined composite end-point of dialysis, renal transplantation or death related to renal disease. Serial serum creatinine levels and all-cause mortality were also recorded. The median total follow-up for core + extension periods was 6.6 years. Many patients from both treatment groups (64% on benazepril and 61% on placebo) received ACE inhibitors during follow-up. In the intention-to-treat analysis of the core + extension data, only 79 of 300 patients from the benazepril group, compared to 102 of the 283 patients from the placebo group needed dialysis or renal transplantation, or died related to renal disease (P < 0.013, log-rank test). The mortality imbalance seen in the core trial was not evident with the longer follow-up (25 deaths in the benazepril and 23 in the placebo group, before dialysis). These data clearly demonstrate a long-term beneficial effect in patients randomized to take benazepril during the core study, but because treatment during the extension period was not randomized, the results of this intention-to-treat analysis need to be interpreted with care.

Fixed combination of benazepril and low-dose amlodipine in the treatment of mild to moderate essential hypertension: evaluation by 24-hour noninvasive ambulatory blood pressure monitoring

The antihypertensive efficacy and tolerability of a fixed combination of benazepril (10 mg) and low-dose amlodipine (2.5 mg) were assessed in 24 patients (mean age, 43.9 years) with uncomplicated mild to moderate essential hypertension [supine diastolic blood pressure (DBP) > or = 95 and < or = 120 mm Hg)]. After 2 weeks of washout taking placebo, patients were randomized to receive the fixed combination or placebo, both administered once daily for 3 weeks, according to a double-blind, crossover design. Patients were checked at the end of the washout period and every 3 weeks thereafter. At each visit, 24-h ambulatory BP monitoring (ABPM) was performed by a noninvasive device (Spacelabs 90207); casual BP (by mercury sphygmomanometer), heart rate (HR), and body weight also were measured. The fixed combination significantly reduced systolic (SBP) and DBP values throughout the 24 h as compared with placebo, without affecting the normal BP circadian variability. The antihypertensive effect of the fixed combination could be observed to a similar extent during the day and night and was still significant 24 h after dosing. HR and body weight were not affected by the treatment. The fixed combination of benazepril 10 mg/amlodipine 2.5 mg was well tolerated, and no patient withdrew from the study because of side effects.

Effect of the angiotensin-converting-enzyme inhibitor benazepril on the progression of chronic renal insufficiency. The Angiotensin-Converting-Enzyme Inhibition in Progressive Renal Insufficiency Study Group

BACKGROUND

Drugs that inhibit angiotensin-converting enzyme slow the progression of renal insufficiency in patients with diabetic neuropathy. Whether these drugs have a similar action in patients with other renal diseases is not known. We conducted a study to determine the effect of the angiotensin-converting-enzyme inhibitor benazepril on the progression of renal insufficiency in patients with various underlying renal diseases.

METHODS

In a three-year trial involving 583 patients with renal insufficiency caused by various disorders, 300 patients received benazepril and 283 received placebo. The underlying diseases included glomerulopathies (in 192 patients), interstitial nephritis (in 105), nephrosclerosis (in 97), polycystic kidney disease (in 64), diabetic nephropathy (in 21), and miscellaneous or unknown disorders (in 104). The severity of renal insufficiency was classified according to the base-line creatinine clearance: 227 patients had mild insufficiency (creatinine clearance, 46 TO 60 ml per minute), and 356 had moderate insufficiency (creatinine clearance, 30 to 45 ml per minute). The primary end point was a doubling of the base-line serum creatine concentration or the need for dialysis.

RESULTS

At three years. 31 patients in the benazepril group and 57 in the placebo group had reached the primary end point (P<0.001). In the benazepril group, the reduction in the risk of reaching the end point was 53 percent overall (95 percent confidence interval, 27 to 70 percent), 71 percent (95 percent confidence interval, 21 to 90 percent) among the patients with mild renal insufficiency, and 46 percent (95 percent confidence interval, 12 to 67 percent) among those with moderate renal insufficiency. The reduction in risk was greatest among the male patients; those with glomerular diseases, diabetic nephropathy, or miscellaneous or unknown causes of renal disease; and those with base-line urinary protein excretion above 1 g per 24 hours. Benazepril was not effective in patients with polycystic disease. Diastolic pressure decreased by 3.5 to 5.0 mm Hg in the benazepril group and increased by 0.2 to 1.5 mm Hg in the placebo group.

CONCLUSIONS

Benazepril provides protection against the progression of renal insufficiency in patients with various renal diseases.

Antianginal effect of transdermal nitroglycerin and oral nitrates given for 24 hours a day in 2,456 patients with stable angina pectoris. The Italian Multicenter Study

The effect of transdermal and oral nitrates on anginal symptoms were compared in a randomized trial of 2,456 out-patients with stable angina pectoris recruited in 206 cardiological centers in Italy. Half of the patients had effort-induced angina, 12% rest angina and 38% "mixed angina". Before enrollment, all of the patients were on stable treatment with oral nitrates either as monotherapy or in combination with other antianginal agents. After a 2-week run-in period on the previous oral nitrate regimen, two thirds of the patients were randomized to receive a nitroglycerin patch 5 mg/24 hours for 2 weeks, the remaining one third continued their previous treatment. The patients subsequently reporting > or = 1 anginal attack/2 weeks were titrated to transdermal nitroglycerin 10 mg/24 hours or to the maximum dose of oral nitrates suggested by the manufacturer for the following 4 weeks; asymptomatic patients continued on the initial dosages. The 2-week anginal attack rate was reduced from 4.9 +/- 5.3 to 1.4 +/- 2.5 in the transdermal nitroglycerin group (-71%), and from 4.5 +/- 4.7 to 1.5 +/- 2.7 (-67%) in the oral nitrate group. The proportion of patients free of angina increased from 12% to 54% (+343%) with transdermal nitroglycerin and from 15% to 49% with oral nitrates (+218%) (p < 0.05). The reduction in angina frequency was similar during the day and during the night. Nocturnal angina was rare in patients with effort angina. However, about half of the patients with rest and "mixed" angina had had nocturnal episodes, the number of which was significantly reduced by both regimens: nighttime asymptomatic patients increased from 45% to 82% in the rest angina group, and from 50% to 83% in the "mixed" angina group, with no differences between treatments. Withdrawals due to side-effects were rare: 1.5% with transdermal nitroglycerin and 1.3% with oral nitrates. Headache was the most common side-effect and was more frequently reported with oral nitrates. Although the lack of a placebo control precludes an absolute evaluation of efficacy, the results of the present study suggest that both transdermal nitroglycerin and oral nitrates may provide relief of anginal symptoms over 24 hours in the majority of stable angina patients. Nocturnal angina, reported by 50% of the patients with rest and mixed angina, is effectively reduced by the administration of nitrates over 24 hours.

Evaluation by 24-hour ambulatory blood pressure monitoring of efficacy of benazepril 20 mg plus hydrochlorothiazide 25 mg fixed combination as compared to captopril 50 mg [corrected] plus hydrochlorothiazide 25 mg fixed combination in treating mild to moderate hypertension: a double-blind, within-patient, placebo-controlled study

In a double-blind, placebo-controlled, three-period cross-over, randomized study we evaluated the efficacy and tolerability of a fixed combination of benazepril 20 mg and hydrochlorothiazide 25 mg (BN + HCT) as compared with the fixed combination of captopril 50 mg and hydrochlorothiazide 25 mg (CP + HCT) by ambulatory blood pressure monitoring (ABPM) in patients with mild to moderate hypertension. Eighteen outpatients, 16 men and 2 women aged 41-58 years, were randomized to receive BN + HCT, CP + HCT, or placebo, all administered once daily for 4 weeks according to a three-period cross-over arranged in a 3 x 3 latin square design. Patients were checked after an initial 3-week washout period and every 4 weeks thereafter. At each visit, 24-h ABPM was performed by a noninvasive device (Spacelabs 5300); causal BP and heart rate (HR) were also measured. Both fixed combinations had a clear-cut antihypertensive effect in comparison with placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Fixed combination of benazepril and very low dose hydrochlorothiazide in the treatment of mild to moderate essential hypertension: evaluation by 24-hour non invasive ambulatory blood pressure monitoring

A double-blind, crossover, placebo-controlled study was undertaken in order to assess the antihypertensive efficacy of a fixed combination of benazepril and hydrochlorothiazide in two different dosages by ambulatory blood pressure monitoring (ABPM). After a three-week placebo wash-out period, 18 patients with mild to moderate essential hypertension, all males, aged 41-60 years, were randomized to receive benazepril 5 mg + hydrochlorothiazide 6.25 mg, benazepril 10 mg + hydrochlorothiazide 12.5 mg or placebo, all given once daily for 4 weeks, according to a 3 crossover period, arranged in a 3 x 3 latin square design. Patients were checked after the wash-out period and every 4 weeks thereafter. At each visit, 24-hour ABPM was performed by a non-invasive device (Spacelabs 90202); causal BP (by mercury sphygmomanometer) and HR were also measured. Both dosages of the fixed combination were equally effective in reducing systolic and diastolic BP values throughout the 24-hour period as compared to the placebo. The antihypertensive effect of the drug could be observed to a similar extent both during the day and night and was still significant 24-hour post-dosing. In addition, the fixed combination did not affect the normal BP circadian variability.

Effects of benazepril on stress testing blood pressure in essential hypertension

The effects of different doses of the angiotensin-converting enzyme inhibitor benazepril on cardiovascular response to a set of standardized laboratory tasks were analyzed. Eighteen patients (15 men and 3 women) with mild-to-moderate essential hypertension were randomly allocated to receive 10 or 20 mg of benazepril, or placebo, each administered once daily for 2 weeks, according to a double-blind, 3-period design. At the end of each treatment period, patients were examined at resting baseline and while performing mental arithmetic, handgrip and cycle ergometry tests. In comparison with placebo, the average reductions in resting systolic blood pressure (BP) were 8.7 mm Hg (95% confidence intervals [CI] -15.2 to -2.1) with 10 mg of benazepril, and 7.8 mm Hg (95% CI -14.4 to -1.3) with 20 mg; the corresponding reductions in resting diastolic BP were 5.1 mm Hg (95% CI -8.7 to -1.4) and 6.8 mm Hg (95% CI -10.4 to -3.1) (all p < 0.05). During mental arithmetic, the reductions in systolic BP were 10.4 mm Hg (95% CI -17.4 to -3.4) with 10 mg of benazepril, and 13.8 mm Hg (95% CI -20.8 to -6.8) with 20 mg; diastolic BP was reduced by 4.5 mm Hg (95% CI -8.5 to -0.5) and 8.3 mm Hg (95% CI -13.2 to -4.3), respectively (all p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of evening versus morning benazepril on 24-hour blood pressure: a comparative study with continuous intraarterial monitoring

In a single-blind, in-patient, crossover study, the influence on the circadian blood pressure (BP) profile of the 9:00 a.m. versus the 9:00 p.m. acute administration of a single dose of benazepril 10 mg, a new angiotensin-converting-enzyme inhibitor, was assessed in 10 hypertensive patients by means of 24-hour intraarterial ambulatory BP monitoring. Mean 24-hour BP for the three treatments (placebo, benazepril a.m., benazepril p.m.) were 155/93, 131/83 and 138/86 mmHg, respectively. No significant differences between the two benazepril schedules were found in terms of either 24-hour or day-time and night-time mean BP values. However, hourly averages showed that benazepril a.m. had a more sustained antihypertensive effect than benazepril p.m., where a loss of efficacy was observed 19 hours after the administration. BP responses to static and dynamic exercise and to cold pressor test were unchanged after both benazepril schedules, as were BP peaks. These results demonstrate that acute benazepril administration markedly reduces systolic and diastolic BP. The morning administration is preferable because it more effectively covers the whole 24 hours than an evening dose.

Effect of cigarette smoking and of a transdermal nicotine delivery system on glucoregulation in type 2 diabetes mellitus

The effect of nicotine absorbed transdermally from a patch (TNS) and from cigarette smoking on insulin secretion and action in Type 2 diabetes has been compared. Twelve Type 2 diabetic smoking patients, aged 51 y, with diabetes for 9 y, treated either with diet and/or oral hypoglycaemic agents, were studied on three occasions, according to a double-blind, placebo-controlled, cross-over design. The subjects were investigated 12 h after their last cigarette or application of one patch of TNS 30 cm2 or TNS placebo, or whilst smoking their usual cigarette. Insulin secretion was assessed by a glucagon (1 mg IV) stimulation test. On a second occasion, insulin action was assessed by a hyperglycaemic-hyperinsulinaemic clamp, the spontaneous hyperglycaemia of the fasting state (8.61 mmol.l-1) being maintained during a 4 h insulin infusion (at 0.1 mU.kg-1.min-1 for the initial 2 h, and 1 mU.kg-1.min-1 during the last 2 h). TNS and the cigarette did not affect endogenous insulin secretion as compared to placebo. During the initial 2 h of the clamp study, plasma insulin increased from 88 to 155 pmol.l-1, hepatic glucose production (3-3H-glucose) was less suppressed after TNS (4.31 mumol.kg-1.min-1) than after placebo (2.5 mumol.kg-1.min-1), but was more suppressed than after cigarette smoking (5.61 mumol.kg-1.min-1). In the last 2 h of the clamp (plasma insulin 646 pmol.l-1), glucose utilization was less stimulated after TNS (36.1 mumol.kg-1.min-1) vs placebo (39.8 mumol.kg-1.min-1), but more than after cigarette smoking (33.6 mumol.kg-1.min-1), primarily because of a decrease in glucose storage.(ABSTRACT TRUNCATED AT 250 WORDS)

Short-term metabolic effects of the ACE-inhibitor benazepril in type 2 diabetes mellitus associated with arterial hypertension

To assess the short-term metabolic effects a long-acting non-sulphydryl ACE-inhibitor benazepril on glycaemic control in Type 2 diabetes mellitus and arterial hypertension, 10 hypertensive diabetic patients treated with glibenclamide were studied in a double-blind, crossover fashion over two 10-day periods in which either benazepril (10 mg/day) or placebo was given. At the end of the 10 day treatment, both blood pressure and plasma glucose concentrations were lower after benazepril versus placebo (benazepril, blood pressure: 143 +/- 11/83 +/- 5 mmHg, plasma glucose: 7.1 +/- 1.2 mmol/l; placebo: blood pressure: 157 +/- 10/99 +/- 2 mmHg, plasma glucose: 8.2 +/- 1 mmol/l, p < 0.05). In response to an oral glucose tolerance test combined with 1 mg intravenous glibenclamide, plasma glucose levels were lower after benazepril versus placebo (0-460 min: 8.4 +/- 0.8 versus 10.5 +/- 0.9 mmol/l, p < 0.05), whereas plasma insulin, C-peptide and glibenclamide concentrations were not different. It is concluded that a short-term administration of benazepril in Type 2 diabetes mellitus reduces blood pressure and improves blood glucose control, most likely by decreasing insulin resistance.

Long-term effects of benazepril on ambulatory blood pressure, left ventricular mass, diastolic filling and aortic flow in essential hypertension

We investigated the long-term effects of benazepril, a new non-sulfydryl angiotensin converting enzyme inhibitor, on ambulatory blood pressure (BP) and left ventricular (LV) anatomy and function in 13 never treated hypertensive patients (mean age 55 years--SD 9). Non-invasive ambulatory BP monitoring (Spacelabs 90202, a reading every 15 min for 24 hours) and standard and pulsed Doppler echocardiography were performed basally and after 12 months of therapy. Echocardiography was performed also at the end of 18th month of treatment. Eleven patients required a single daily dose of benazepril 10 (n = 9) or 20 (n = 2) mg, and two patients of 20 mg plus chlorthalidone 25 mg, to achieve clinical BP control. Average 24 h systolic/diastolic BP was 156/100 mmHg (SD 17/5) basally and 144/90 mmHg (SD 16/7) at the end of the 12th month of treatment (all p less than 0.01), LV mass index was 133 g/m2 basally and 113 g/m2 at the 12th month (p less than 0.01), early transmitral flow velocity (peak E) was 0.43 m/s (SD 0.11) basally and 0.62 (SD 0.13) m/s at the 12th month (p less than 0.01), and late transmitral flow velocity (peak A) did not change [0.67 (SD 0.10) m/s basally and 0.64 (SD 0.11) m/s at the 12th month]. Peak A/peak E ratio decreased from 1.69 (SD 0.57) to 1.31 (SD 0.37) (p less than 0.01). Peak aortic velocity, aortic acceleration time and aortic acceleration did not change. The per cent reduction of LV mass index was more closely related to the reduction of average 24 h systolic (r = 0.66, p = 0.013) and diastolic (r = 0.72, p = 0.005) BP than to the reduction of casual systolic (r = 0.37, p = NS) and diastolic (r = 0.42, p = NS) BP. None of the echocardiographic indices changed between the 12th and 18th month of treatment. In a control group of 13 age- and sex-matched healthy normotensive volunteers who underwent 24 h ambulatory BP monitoring and echocardiography twice, 12 months apart, there were no statistically significant BP or echographic changes. In summary, long-term antihypertensive treatment with benazepril provided and effective 24 h BP control, associated with regression of LV hypertrophy and improvement in LV diastolic filling, without changes in LV systolic function.

A comparison of metoprolol OROS with antenolol in the treatment of effort angina pectoris: a randomized double-blind study

The antianginal efficacy of metoprolol OROS has been investigated in comparison with that of atenolol in a multicenter double-blind cross-over trial carried out in patients with stable effort angina. OROS (ORally OSmotic) is a new semi-permeable delivery system with very slow osmotic release of the active drug, which is maintained at virtually constant plasma levels throughout the 24 hours. At the end of a 2-week run-in period, 53 patients with chronic coronary artery disease and documented ischemia during bicycleergometric exercise test were given, on double-blind condition, metoprolol OROS 21/285 and atenolol 100 mg in random order for 4 weeks each. On the last day of each cross-over period, patients underwent a bicycleergometric exercise test 24 hours after the last drug intake. The mean number of anginal attacks (2.54 during the 2-week run-in period) decreased under both metoprolol OROS (1.29 and 1.13 after 2 and 4 weeks of treatment, respectively) and atenolol (1.29 and 0.73 after 2 and 4 weeks of treatment, respectively), with no difference between the two beta-blockers. The same behaviour was observed as regards the nitroglycerin tablets consumption. The exercise test variables (i.e. duration of exercise, maximum workload and peak exercise values of systolic and diastolic blood pressure, heart rate and ST-segment depression) did not differ between the two treatments and did not show a time-effect. The percentage of patients reporting adverse effects was low with both treatments. Two patients were withdrawn from the study during atenolol (gastralgia and heartburn, respectively), and one during metoprolol OROS (gastralgia).(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of cadralazine in a large group of hypertensive patients chronically treated with cadralazine: advantage over a conventional study in a small group of patients

The concentrations of cadralazine in plasma were studied in 101 hypertensive patients treated with oral doses of 10, 15, or 20 mg of cadralazine once daily. Most of the patients received additionally a beta-blocking drug (n = 87) and a diuretic (n = 52). Few blood samples were collected in each patient on several occasions during the treatment, which usually lasted for more than 6 months. No accumulation of cadralazine in plasma occurred in any of the patients and the maximum concentrations were similar to those recorded in a small sample of healthy volunteers. The terminal half-life of elimination (3.6 h) was longer than that observed in healthy subjects (approximately 2.5 h). Conversely, the total clearance (197 ml/min) was lower (285 ml/min in healthy). The half-life and the total clearance in plasma were not dose dependent. In the patients treated for more than 6 months, no change in the pharmacokinetics of cadralazine was detected. The description of the distribution of concentrations showed that one-half of the patients behaved similarly to healthy subjects concerning half-life and total clearance. The other half presented a slower elimination of the drug (t 1/2 = 4.4 h and ClT = 130 ml/min) and these patients were significantly older (p = 0.01) than the former. This suggests that special attention should be paid to old hypertensive patients when a dose higher than 15 mg once daily is prescribed. Though concentrations were proportional to the dose, the body weight was not found to be a determining factor for dose adjustment.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of left ventricular ejection fraction by magnetic resonance imaging and radionuclide ventriculography in idiopathic dilated cardiomyopathy

To assess the validity of gated magnetic resonance imaging (MRI) in determining left ventricular (LV) ejection fraction (EF), MRI (Spin Echo, multislice-multiphase technique on the short-axis plane) was compared with equilibrium radionuclide ventriculography in 32 patients with idiopathic dilated cardiomyopathy. All patients underwent MRI and radionuclide ventriculography, performed consecutively on the same day (mean time interval between the 2 examinations: 40 minutes). Comparison with LVEF showed a high correlation (y = 0.79 X +3.51, r = 0.91; p less than 0.001). Mean difference between radionuclide ventriculography and MRI data was 1.7, with the 95% confidence interval 0.71 to 2.68: MRI slightly underestimated LVEF. MRI interobserver and intrapatient variability (assessed in 15 of 32 patients) showed a high correlation (r = 0.91, r = 0.98). In conclusion, data suggest that MRI, using the short-axis approach and the multislice-multiphase technique, is an accurate, noninvasive, highly reproducible method of evaluating LVEF in patients with idiopathic dilated cardiomyopathy.

Comparative evaluation of cardioselectivity of metoprolol OROS and atenolol: a double-blind, placebo-controlled crossover study

Cardioselectivity of a single oral dose of metoprolol oral osmotic (OROS) (14/190 mg) and atenolol (100 mg) was compared in 12 patients with reversible obstructive airway disease by assessing the dose-response curve to increasing doses of inhaled salbutamol. The beta-blocking activity of the two drugs, which was determined by measuring heart rate, blood pressure, and derived indexes at peak plasma drug levels, was similar. Both metoprolol and atenolol significantly reduced forced vital capacity and peak expiratory flow, with no difference between drugs. Atenolol but not metoprolol also significantly reduced forced expiratory volume in 1 second and specific airway conductance. Both metoprolol and atenolol shifted the dose-response curve of specific airway conductance to the right. The results indicate that the new OROS delivery system for metoprolol, which produces a relatively constant plasma drug level, provides a cardioselectivity comparable to or greater than that of atenolol at maximum plasma levels.

Transient myocardial ischaemia: a multivariate analysis on clinical, angiographic and ergometric variables

The availability of ambulatory ECG monitoring allows identification of transient myocardial ischaemia, the clinical relevance of which is currently being investigated. Ninety-four consecutive patients with ischaemic heart disease and a positive exercise test (greater than or equal to 1 mm ST-segment depression) were studied to evaluate the prevalence of transient myocardial ischaemia (either painless or painful) during 24-h dynamic electrocardiogram (ECG) and the clinical, angiographic and ergometric variables predicting its appearance. Two-hundred-and-eighty-one episodes of transient electocardiographic myocardial ischaemia were recorded in 69 patients (73.4% of all patients). Transient myocardial ischaemia was more frequent, although not significantly so, in patients with diabetes, with previous myocardial infarction, or with multivessel disease. When tested by multivariate analysis, neither the clinical variables nor the severity of coronary artery disease allowed prediction of the occurrence of transient myocardial ischaemia during dynamic ECG. The duration of exercise testing up to the ischaemic threshold (ST-segment depression = 1 mm) and the peak heart rate during exercise were more accurate predictors of transient myocardial ischaemia (P = 0.019 and 0.012 respectively). Patients with transient myocardial ischaemia had a lower ischaemic threshold (355 +/- 175 vs 498 +/- 150 s, mean +/- SD, P = 0.001) despite a lower peak heart rate (129 +/- 18 vs 137 +/- 12 beats min-1, P = 0.047) than patients without transient myocardial ischaemia. In conclusion, exercise testing may help select patients for examination by dynamic ECG.(ABSTRACT TRUNCATED AT 250 WORDS)

Blunting of atrial natriuretic factor response to volume expansion by benazepril in hypertensive patients

To verify the hypothesis that the angiotensin converting enzyme (ACE) level may affect the metabolism of circulating atrial natriuretic factor (ANF), the acute and chronic effects of benazepril on plasma ANF levels were studied in hypertensive patients under basal conditions and in response to acute volume expansion. Ten essential hypertensives entered a double-blind crossover study, and were randomly allocated either to placebo or to 10 mg benazepril orally once a day for 2 days; after a placebo washout period of 2 days the groups were crossed over. On the second day of each crossover period, volume expansion was induced by infusing 1 litre saline in 30 min, and blood samples for ANF measurements were drawn at times -5, 0, 5, 15, 30, 35, 40, 50 and 60 min. Oral benazepril at 10 mg/day was then given to all patients for 4 weeks, and the volume expansion with saline was repeated. After the 2-day acute benazepril treatment, blood pressure fell from 166.1 +/- 3.6/105.1 +/- 0.9 to 140.1 +/- 4.6/85.6 +/- 2.1 mmHg (P less than 0.01 for both systolic and diastolic blood pressure), whereas ANF fell from 29.4 +/- 3.6 to 24.1 +/- 3.7 pg/ml (NS) after the acute benazepril treatment and to 17.7 +/- 3.6 pg/ml (P less than 0.01) after the chronic benazepril treatment. The volume expansion itself did not induce significant changes in mean arterial pressure, either during the placebo treatment or during the acute chronic benazepril treatment. The rise in ANF values in response to saline infusion during placebo was prompt, beginning at min 15 and reaching a maximum at min 40.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional and systemic hemodynamic and humoral effects of transdermal nitroglycerin in mild hypertension

Venous distensibility, forearm blood flow (FBF, plethysmographic technique), systemic blood pressure (BP), and derived forearm vascular resistances were measured in 11 borderline-mild hypertensive, otherwise healthy male subjects for a 24-h period during either placebo or transdermally delivered nitroglycerin (NTG 10 mg/24 h). The drug caused arteriolar and venular forearm vasodilation and hypotension which, although persisting throughout the 24-h observation period, reached an apparent maximum during the first hours but later tended to wane. Since NTG plasma levels were constant at that time, the data may suggest development of vascular hyporesponsiveness during continuous exposure to NTG. Venous hematocrit (Hct) decreased during transdermal NTG, indicating the plasma volume expanding action of the drug, apparently dissociated from vasodilation per se. Because no significant changes in either plasma norepinephrine (NE) or plasma renin activity occurred in these subjects, counterregulatory sympathetic or angiotensin II (AII)-mediated vasoconstriction was probably not involved in the hemodynamic action of transdermally delivered NTG.

Antihypertensive effect of a new formulation of slow release oxprenolol in essential hypertension

To test whether a new formulation of a slow release oxprenolol (SLOx) can produce a steady 24-h antihypertensive effect, we recorded 24-h intraarterial blood pressure (Oxford technique) in eight ambulant inpatients (age 44.5 +/- 3.0 years, mean +/- SE) with a mild or moderate hypertension who were untreated since three weeks. The study was started seven days after hospitalization and was conducted according to a randomized doubleblind cross-over design. Blood pressure recordings were made after (a) a 7-day administration of SLOx in a single evening dose, and (b) a 7-day administration of placebo. This design allowed to determine the effect of SLOx without interference from nonspecific blood pressure lowering factors. Blood pressure effects of handgrip, submaximal cyclette exercise, and cold pressor test 20-24 h after the administration of SLOx and placebo were also evaluated. The blood pressure tracing was analyzed beat-to-beat by a computer which provided also the analysis of the heart rate data. The 24-h mean systolic and diastolic blood pressure measured during placebo were 144.6 +/- 6.4 and 81.1 +/- 3.9 mm Hg, the corresponding heart rate being 76.9 +/- 3.5 beats/min. SLOx reduced these values by 6.2, 10.6, and 4.8%, respectively, all effects being similarly evident throughout the blood pressure recording. The pressor responses to handgrip, cyclette exercise, and cold pressor test were not affected by SLOx. By contrast, the small tachycardic response to handgrip and the large tachycardic response to submaximal cyclette exercise were significantly reduced by the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Antihypertensive activity of a new vasodilator, cadralazine, administered alone or in combination with a beta-blocker

The antihypertensive activity of a new arterial dilator, cadralazine, was evaluated in 40 patients with mild-to-moderate arterial hypertension. Cadralazine was given once daily over 6 weeks, and blood pressure and heart rate were recorded 24-26 hours after dosing. Cadralazine dose was 10 mg daily initially, and 15 or 20 mg daily from the 3rd or 5th trial week according to a target diastolic pressure reduction to 95 mmHg or below. Slow-release metoprolol 200 mg once daily was added when heart rate increase exceeded 25% of the pretreatment value. Blood pressure showed a significant and progressive reduction throughout the study period, both in the patients receiving cadralazine as monotherapy (19 patients) and in those who added metoprolol (21 patients). The target diastolic pressure reduction was reached in 2 patients with the 10-mg dose, in 19 of the remaining 38 patients with the 15-mg dose, and in 13 of the other 19 patients with the 20-mg dose. Considering only those patients who did not add metoprolol, the target was reached in the 2 patients with the 10-mg dose, in 10 of the 19 patients with the 15-mg dose and in 7 of the 19 patients with the 20-mg dose. None of the laboratory tests showed clinically relevant changes. Neither LE cells nor antinuclear antibodies were found. In conclusion, cadralazine is a promising long-acting antihypertensive vasodilator. A clinically satisfactory antihypertensive effect is achieved mostly by a 15-mg or a 20-mg dose given once daily.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic effects of once a day administration of combined chlorthalidone and metoprolol slow-release in essential hypertension

The effects of a fixed combination of chlorthalidone (25 mg) and metoprolol slow-release (200 mg) (CM) on 24 hour blood pressure (BP) and heart rate (HR) values and their variabilities were evaluated in 6 ambulant hypertensives by the Oxford method, to obtain continuous intra-arterial recording and by computer to have a beat-to-beat analysis of the data. Compared to pre-treatment values, average 24 hour HR and mean BP recorded after 7-10 days of once daily CM orally administration were reduced by 18.4 +/- 3.1 and 14.7 +/- 3.0%, respectively. The effects of CM were also evident during isometric and dynamic exercise, whose pressor and tachycardic responses were left unimpaired (BP) or were only slightly reduced (HR) by CM. The long- and short-term BP and HR variabilities (calculated as variation coefficients among and within half hours, and within minutes) were also left unaffected by CM. These findings indicate that once a day administration of CM effectively reduces BP and HR over the 24 hours, without interfering with cardiovascular homeostasis. The effective and persistent reduction in both these variables (as well as their occurrence during exercise) suggests that the antihypertensive action of this treatment is accompanied by a clear-cut reduction in cardiac work.

Ventilatory effects of selective beta 1-(prenalterol) or beta 2-(salbutamol) adrenoceptor agonism in man

We compared the ventilatory effects of prenalterol (beta 1-selective adrenoceptor agonist) with those of salbutamol (beta 2-selective adrenoceptor agonist) in 6 healthy volunteers. Two intravenous doses of prenalterol (1 mg/60 min, 2 mg/60 min) and of salbutamol (300 micrograms/60 min, 600 micrograms/60 min) were given in random order in 4 separate sessions of 60 minutes each. Pulmonary ventilation per minute (V'E) increased only on the high dose of salbutamol. Mouth occlusion pressure (P0.1) did not vary either on prenalterol or on salbutamol. Only the high dose of salbutamol induced (1) an increase in tidal volume (VT) without changes in respiratory rate (RR), (2) an increase in mean inspiratory flow (VT/Ti) without changes in the fraction of inspiratory time to total cycle duration (Ti/Ttot). During forced expiration, salbutamol elicited a small bronchodilating effect at the level of both large (FEV1, FEF25-75, FEF50) and small (FEV3, FEF75-85, FEF75) airways. Prenalterol induced a very small dilatation of the large airways, and a somewhat more pronounced effect at the level of the small airways. Neither the indexes of ventilatory pattern nor those of bronchial tone showed any statistical or biological differences between values on prenalterol and values on salbutamol. However, both the former and the latter indexes showed a trend to be higher on salbutamol than on prenalterol. Results suggest that salbutamol-induced increase in pulmonary ventilation per minute in subjects without bronchial obstruction is likely the result of a reduced bronchomotor tone at rest, leading to an increase in tidal volume because of the rise in the VT/Ti ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular hypertrophy regression in hypertensive patients treated with metoprolol

The long-term effects of metoprolol monotherapy, 100 mg b.i.d., for 16-18 months, were investigated in 8 previously untreated essentially hypertensive patients (resting blood pressure greater than 155/95 mmHg) and echocardiographic evidence of left ventricular hypertrophy (LVH) (left ventricular mass by Penn Cube formula greater than 215 g). Echocardiographic studies, according to the American Society of Echocardiography recording techniques and measurements criteria, were performed before starting treatment and at the end of follow-up. Metoprolol induced a decrease in systolic and diastolic blood pressure and heart rate, accompanied by a reduction of interventricular septum and posterior wall thickness (from 1.21 cm to 1.10 cm, and from 1.15 cm to 1.06 cm, respectively), left ventricular mass index and mean wall stress. All these changes were significant (p less than 0.01). Cardiac index decreased from 3017 ml/m2 to 2632 ml/m2 (p less than 0.01), mostly because of the reduction in the heart rate. In fact, stroke index, ejection fraction and fractional shortening all slightly increased during treatment in respect to pre-treatment values. Plasma renin activity fell from 1.45 ng/ml/h to 0.81 ng/ml/h (p less than 0.01), whereas both plasma noradrenaline and adrenaline concentration at rest did not change. Results indicate that in essentially hypertensive patients who have already developed LVH as a consequence of the hypertension, a long-term metoprolol therapy can successfully induce a reversal of LVH together with an effective blood pressure control, without noticeable adverse effects of changes in cardiac performance.

Noninvasive assessment of chronotropic and inotropic response to preferential beta-1 and beta-2 adrenoceptor stimulation

The relative chronotropic and inotropic activity of preferential beta 1- and beta 2-adrenoceptor stimulation was investigated in seven healthy male subjects in a randomized within-subject, single-blind study. Two doses of beta 1-selective agonist prenalterol (1 mg/hr or 2 mg/hr) and of beta 2-selective agonist salbutamol (300 micrograms/hr or 600 micrograms/hr) were infused intravenously in four separate sessions, with intervals of at least 48 hr between sessions. At each session cuff blood pressure and heart rate (HR) were measured and some hemodynamic information on the inotropic state were derived by echocardiography. Both prenalterol and salbutamol induced increases in HR, but tachycardia was greater after salbutamol, whereas the positive inotropic response to beta-stimulation was greater after prenalterol. At comparable HR rises (prenalterol, from 66.0 +/- 5.5 to 72.2 +/- 4 bpm; salbutamol, from 64.6 +/- 6 to 70.0 +/- 7 bpm), inotropic response seemed to be greater after prenalterol than after salbutamol (systolic blood pressure [SBP]: 133.5 +/- 8 and 120.7 +/- 8 mm Hg; mean velocity of circumferential fiber shortening [Vcf]: 1.54 +/- 0.13 and 1.31 +/- 0.12 c/s; ejection fraction [EF]: 72.4% +/- 5% and 69.5% +/- 4%; stroke index: 47.4 +/- 4 and 41.7 +/- 3 ml/m2). In presence of a chronotropic effect (HR from 64.6 +/- 6 to 70.0 +/- 7 bpm), the low salbutamol dose did not induce any changes in the indices of inotropism (SBP: from 119.2 +/- 6 to 120.7 +/- 8 mm Hg; mean Vcf: from 1.28 +/- 0.11 to 1.31 +/- 0.12 c/s; EF: from 68.1% +/- 5% to 69.5% +/- 4%; stroke index: from 40.2 +/- 3 to 41.7 +/- 3 ml/m2.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma norepinephrine and left ventricular hypertrophy in systemic hypertension

The relations between some pressure and humoral factors, and some echocardiographic indexes of left ventricular (LV) hypertrophy were studied in 64 patients with essential hypertension. Fifty-seven percent of these patients showed echocardiographic evidence of LV hypertrophy (LV mass greater than 215 g). Multivariate stepwise regression analysis showed that only mean blood pressure (BP) and circulating norepinephrine (NE) levels were significantly related to LV mass index in the group of patients with LV hypertrophy. However, mean BP was the only factor related to LV mass index in the subgroup of patients with LV hypertrophy and plasma NE within the normal laboratory range, whereas NE was the sole factor related to LV mass index in the subgroup with LV hypertrophy and abnormally elevated NE levels (greater than mean + 2 standard deviations of the normal laboratory range). Correlation of LV mass index vs NE was -0.35 (not significant) in the former group of patients and 0.89 (p less than 0.01) in the latter group. NE showed no relation with the echocardiographic variables in the hypertensive patients without LV hypertrophy; in this group, diastolic BP was the only factor related to LV mass index. Circulating NE levels were slightly higher in patients with LV hypertrophy (213 +/- 68 ng/liter) than in those without LV hypertrophy (187 +/- 46 ng/liter), but differences were not significant when adjusting NE for age. Plasma renin activity was not dissimilar in the absence or presence of hypertrophy. In conclusion, our findings suggest that NE might be associated with pressure factors in regulating LV hypertrophy development only in a subgroup of hypertensive patients characterized by echocardiographic LV hypertrophy and abnormally elevated circulating NE levels.

[Continuous 24-hour registration of intra-arterial pressure in basal states and during therapy with a fixed slow-release oxprenolol-chlorthalidone combination, administered once a day]

Intra-arterial 24 hour blood pressure (BP) recording (OXFORD MEDILOG) was carried out in 10 patients with essential hypertension, 6 males and 4 females, aged between 41 and 58 years, 3 at WHO stage 1 and 7 at stage 2, in basal conditions and after 6 weeks of treatment with a fixed combination of 160 mg of slow-release oxprenolol and 20 mg of chlorthalidone per tablet (tb). The fixed combination was given once daily, in the morning, at the dosage of 1 tb, which was increased to 2 tbs o.d. after the first 2 weeks in 6 patients. Computer calculated mean BP and heart rate (HR) values from each consecutive hour of the day were obtained in all patients. Hourly trend of BP and HR were plotted and circadian variations were thus determined. Treatment with fixed combination o.d. significantly reduced systolic and diastolic BP, compared to pretreatment values, throughout of the 24 hours (p less than 0.01; p less than 0.001), without altering the circadian rhythm. Before and after 6 weeks of treatment, a bicycle exercise test was performed in 8 patients, who reached 85% of the maximal predicted HR. Pretreatment resting mean BP (+/- SD) was 190 +/- 31/108 +/- 10 mmHg (HR: 68 +/- 9 b/min) and those during the last minute of exercise 242 +/- 29/125 +/- 5 mmHg (HR: 147 +/- 13 b/min); posttreatment resting BP was 161 +/- 20/88 +/- 7 mmHg (HR: 58 +/- 7 b/min) and at peak exercise, 212 +/- 16/106 +/- 7 mmHg (p less than 0.025 for the systolic pressure; p less than 0.001 for the diastolic pressure).(ABSTRACT TRUNCATED AT 250 WORDS)

The adrenergic contribution to glucose counterregulation in type I diabetes mellitus. Dependency on A-cell function and mediation through beta 2-adrenergic receptors

In order to assess the adrenergic contribution to hypoglycemic glucose counterregulation in type I diabetes mellitus and to determine whether the adrenergic contribution is mediated through beta 1- or beta 2-adrenergic receptors, hypoglycemia was induced by an i.v. insulin infusion (30 mU/m2 x min) for 60 min in 11 insulin-dependent diabetic patients (IDDM), 5 with normal plasma glucagon responses and 6 with blunted responses, and also in 7 age-weight-matched nondiabetic subjects. Rates of plasma glucose decrease and postnadir increase, as well as plasma concentrations of free insulin and of counterregulatory hormones, were measured when insulin was infused alone, and when insulin was infused along with propranolol (a beta 1- and beta 2-adrenergic receptor antagonist) or metoprolol (a selective beta 1-antagonist). Postnadir plasma glucose recovery was decreased in IDDM with blunted plasma glucagon responses (21 +/- 0.8 mumol x L-1 x min-1, P less than 0.001), but was normal in patients with normal plasma glucagon responses (30 +/- 0.4 versus 33 +/- 0.5 mumol x L-1 x min-1 in nondiabetic subjects, P = NS). Postnadir plasma glucose recovery was not affected by either propranolol or metoprolol in normal subjects and in IDDM with normal glucagon responses. However, in IDDM with blunted plasma glucagon responses, postnadir plasma glucose recovery was further decreased by propranolol (14 +/- 0.6 mumol x L-1 x min-1, P less than 0.01), but was unaffected by metoprolol (22 +/- 0.9 mumol x L-1 x min-1, P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

[Early exercise test after myocardial infarct: prognostic stratification]

Exercise testing in myocardial infarction before discharge has been used for treatment and exercise prescription in the post-hospital phase. Aim of this study was to investigate the prognostic significance, within one year after the infarction, of submaximal exercise testing before discharge. 428 patients performed the test 14.5 days after the acute episode and were followed for 12 months. The following variables were examined: heart rate, blood pressure, rate-pressure product at maximum exercise, total work and reasons for stopping the test (fatigue, submaximal HR, BP greater than or equal to 200/110, hypotension, ischemic or arrhythmic response). Two events were considered: 1) non fatal reinfarction; 2) cardiac death. Two methods of multivariate analysis (Cox's model regression analysis and discriminant analysis) were used. None of the considered variables was found to be predictive of non fatal reinfarction. According to Cox's model total performed work and hypertensive response were found to be predictive of cardiac death, while using discriminant analysis only total work had a predictive value (discriminant function: L = 0.00094 X total work performed + 1.48643; p less than 0.01). In detail, the higher the total work, the better the probabilities of survival, while in patients who stopped the test because of hypertension, the probabilities of cardiac death were lower. Exercise testing performed in uncomplicated myocardial infarction before hospital discharge provides, the basis for a more rational management of patients in the post-infarction phase, and contributes to identify a subset of high-risk patients.

Relationships between plasma catecholamines, renin, age and blood pressure in essential hypertension

The aim of this study was to examine the interrelationships between age, plasma catecholamines, plasma renin activity (PRA) and blood pressure in essential hypertensive (EH) patients. PRA, plasma noradrenaline (NA) and adrenaline (A) were measured in 76 consecutive EH patients (WHO stages 1-2, aged 24-66 years) and in 28 normotensive subjects (aged 25-64 years) studied at rest in supine position after 5 days of normal fixed sodium and potassium intake. Both plasma NA and A were slightly but significantly higher in EH patients (p less than 0.05). While no relationship was found between the various parameters in normotensive subjects, in EH patients, particularly those at WHO stage 2, plasma NA was directly related to mean blood pressure (MBP) (p less than 0.001) and PRA (p less than 0.01). Plasma A was weakly related to MBP (p less than 0.05); PRA was inversely related to age (p less than 0.01) but no relationship was found between NA or A and age. Partial correlation analysis confirmed all these relationships. In fact, NA was related to MBP also considering constant PRA (p less than 0.001) or age (p less than 0.001), and NA was related to PRA also considering constant MBP (p less than 0.01) or age (p less than 0.001). Acute pharmacological alpha- and beta-blockade, with labetalol 100 mg i.v., induced a reduction of MBP which was directly related to basal plasma NA (p less than 0.001). These results support the view that in EH the sympathetic nervous system might be in part responsible for PRA levels and for the severity of hypertension.

Antihypertensive activity of once daily metoprolol alone and with chlorthalidone and comparison with a twice daily regimen

In a multicentre, double-blind (DB), within-patient study, the antihypertensive effectiveness and tolerability of two oral administration schedules of metoprolol (M) 100 mg b.i.d. versus 200 mg once daily (o.d.), were investigated in 103 outpatients with mild to moderate essential hypertension. The study lasted 14 weeks and was divided into 3 periods: a) a weeks of single-blind (SB) placebo wash-out; b) 4 weeks of SB administration of M 100 mg b.i.d.; at the end of the second week of this period, chlorthalidone (C) 25 mg was added in patients with a recumbent diastolic blood pressure (BP) still greater than 95 mmHg and was continued throughout the following period; and c) DB cross-over administration of M 200 mg/d for 4 weeks on a b.i.d. schedule and 4 weeks on a once daily schedule. In comparison with pretreatment values, heart rate and systolic and diastolic BP were reduced (p less than 0.001) by both M administration schedules; there was no differences between the once and twice daily treatment regimens. During M once daily, betablockade was still maintained over 24 hours or longer, as the heart rate remained significantly lower than the basal value. In 57 patients, C was added at the end of the second week of SB M administration, and a further decrease in BP was observed; again, there was no significant change during once and twice daily M administration. Unwanted effects during M treatment were of minor severity, and the majority occurred when C, too, was added.

Interaction between oxprenolol and indomethacin on blood pressure in essential hypertensive patients

A double-blind, cross-over study in 16 patients with essential hypertension was carried out, to evaluate any possible interference by indomethacin, a known prostaglandin-synthetase inhibitor, with the antihypertensive effect of oxprenolol, a non-selective beta-adrenoceptor blocking agent. Both indomethacin and oxprenolol, as well as the two drugs combined, inhibited plasma renin activity; no change was found in urinary sodium excretion or body weight. Oxprenolol alone caused a highly significant decrease in the systolic ( - 10.4 mmHg, p less than 0.001), diastolic ( - 7.4 mmHg, p less than 0.001) and mean ( - 7.7 mmHg, p less than 0.01) blood pressures, whereas indomethacin did not influence blood pressure. When the two drugs were given in combination, blood pressure decreased (systolic: - 5.9 mmHg; diastolic: - 4.0 mmHg; mean: - 4.6 mmHg), but the changes induced in blood pressure were reduced by about 50% when compared with those in the oxprenolol alone period. The data show that indomethacin seems to interfere with the antihypertensive effect of oxprenolol, by an action which may be due to the inhibition of prostaglandin synthesis.

A fixed combination of oxprenolol slow-release and chlorthalidone once daily in treatment of mild to moderate hypertension

In a multicenter, single-blind, interpatient study, 103 outpatients with mild to moderate hypertension were given, after 2 weeks of placebo wash-out, 160 mg oxprenolol slow-release in fixed combination with chlorthalidone (20 mg per tablet) (SROC 160) once daily or conventional oxprenolol (80 mg) in fixed combination with chlorthalidone (10 mg per tablet) (COC 80) twice daily for 8 weeks. Throughout the study 22 of 51 patients on SROC 160 and 24 of 51 on COC 80 received 1 tablet once daily and, respectively, 1 tablet twice daily. The remaining patients of both groups double the corresponding dosage after the first 4 weeks. Systolic and diastolic blood pressure decreased on both treatments without and difference observed between the groups. Diastolic blood pressure normalization was achieved in both groups in the same number of patients (35). Minor side effects occurred on both treatments: only one patient on SROC 160 interrupted the study due to severe dizziness and fatigue. The advantages are discussed as regards patient's compliance with administration of fixed combination SROC 160 once daily in treatment of mild to moderate hypertension.

Antihypertensive effect of oxprenolol and chlorthalidone in fixed combination, given once daily

In a multicentre, single-blind, within-patient study, the effectiveness and tolerability of the fixed combination oxprenolol 80 mg + chlorthalidone 10 mg per tablet given once daily, compared to the well established b.i.d. schedule, has been investigated in forty out-patients with mild to moderate hypertension. After a two-weeks placebo wash-out, twenty patients were given 1 tablet b.i.d. of the fixed combination for 4 weeks and thereafter 2 tablets once-daily for a further 4 weeks; the remaining twenty patients were given the fixed combination in the reverse order. There was no significant difference in clinical response between the two treatment regimes, which were equally effective and well tolerated. However, patient compliance might be considerably improved with the once-daily dosage schedule of the fixed combination.